'revert network patch, added aufs2'

1 files changed, 24089 insertions, 0 deletions

diff --git a/patches/aufs2-standalone.patch b/patches/aufs2-standalone.patch
new file mode 100644
index 0000000..f10d542
--- /dev/null
+++ b/patches/aufs2-standalone.patch
@@ -0,0 +1,24089 @@
+aufs2 standalone patch for linux-2.6.28
+
+diff --git a/fs/Kconfig b/fs/Kconfig
+index 522469a..6ef091b 100644
+--- a/fs/Kconfig
++++ b/fs/Kconfig
+@@ -1122,6 +1122,8 @@ config UFS_DEBUG
+ 	  Y here.  This will result in _many_ additional debugging messages to be
+ 	  written to the system log.
+ 
++source "fs/aufs/Kconfig"
++
+ endmenu
+ 
+ menuconfig NETWORK_FILESYSTEMS
+diff --git a/fs/Makefile b/fs/Makefile
+index d9f8afe..1f206a2 100644
+--- a/fs/Makefile
++++ b/fs/Makefile
+@@ -122,3 +122,4 @@ obj-$(CONFIG_HPPFS)		+= hppfs/
+ obj-$(CONFIG_DEBUG_FS)		+= debugfs/
+ obj-$(CONFIG_OCFS2_FS)		+= ocfs2/
+ obj-$(CONFIG_GFS2_FS)           += gfs2/
++obj-$(CONFIG_AUFS_FS)           += aufs/
+diff --git a/fs/namei.c b/fs/namei.c
+index d34e0f9..2779304 100644
+--- a/fs/namei.c
++++ b/fs/namei.c
+@@ -341,6 +341,7 @@ int deny_write_access(struct file * file)
+ 
+ 	return 0;
+ }
++EXPORT_SYMBOL(deny_write_access);
+ 
+ /**
+  * path_get - get a reference to a path
+@@ -1212,7 +1213,7 @@ out:
+  * needs parent already locked. Doesn't follow mounts.
+  * SMP-safe.
+  */
+-static struct dentry *lookup_hash(struct nameidata *nd)
++struct dentry *lookup_hash(struct nameidata *nd)
+ {
+ 	int err;
+ 
+@@ -1221,8 +1222,9 @@ static struct dentry *lookup_hash(struct nameidata *nd)
+ 		return ERR_PTR(err);
+ 	return __lookup_hash(&nd->last, nd->path.dentry, nd);
+ }
++EXPORT_SYMBOL(lookup_hash);
+ 
+-static int __lookup_one_len(const char *name, struct qstr *this,
++int __lookup_one_len(const char *name, struct qstr *this,
+ 		struct dentry *base, int len)
+ {
+ 	unsigned long hash;
+@@ -1243,6 +1245,7 @@ static int __lookup_one_len(const char *name, struct qstr *this,
+ 	this->hash = end_name_hash(hash);
+ 	return 0;
+ }
++EXPORT_SYMBOL(__lookup_one_len);
+ 
+ /**
+  * lookup_one_len - filesystem helper to lookup single pathname component
+diff --git a/fs/open.c b/fs/open.c
+index 83cdb9d..bb43dab 100644
+--- a/fs/open.c
++++ b/fs/open.c
+@@ -222,6 +222,7 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
+ 	mutex_unlock(&dentry->d_inode->i_mutex);
+ 	return err;
+ }
++EXPORT_SYMBOL(do_truncate);
+ 
+ static long do_sys_truncate(const char __user *pathname, loff_t length)
+ {
+diff --git a/fs/super.c b/fs/super.c
+index 400a760..a1df361 100644
+--- a/fs/super.c
++++ b/fs/super.c
+@@ -270,6 +270,7 @@ int fsync_super(struct super_block *sb)
+ 	__fsync_super(sb);
+ 	return sync_blockdev(sb->s_bdev);
+ }
++EXPORT_SYMBOL(fsync_super);
+ 
+ /**
+  *	generic_shutdown_super	-	common helper for ->kill_sb()
+diff --git a/fs/sync.c b/fs/sync.c
+index 2967562..34040d6 100644
+--- a/fs/sync.c
++++ b/fs/sync.c
+@@ -104,6 +104,7 @@ long do_fsync(struct file *file, int datasync)
+ out:
+ 	return ret;
+ }
++EXPORT_SYMBOL(do_fsync);
+ 
+ static long __do_fsync(unsigned int fd, int datasync)
+ {
+diff --git a/include/linux/Kbuild b/include/linux/Kbuild
+index e531783..14ecb7c 100644
+--- a/include/linux/Kbuild
++++ b/include/linux/Kbuild
+@@ -34,6 +34,7 @@ header-y += atmppp.h
+ header-y += atmsap.h
+ header-y += atmsvc.h
+ header-y += atm_zatm.h
++header-y += aufs_type.h
+ header-y += auto_fs4.h
+ header-y += ax25.h
+ header-y += b1lli.h
+diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
+index 29aec6e..dfcb13b 100644
+--- a/include/linux/lockdep.h
++++ b/include/linux/lockdep.h
+@@ -58,7 +58,7 @@ enum lock_usage_bit
+ #define LOCKF_USED_IN_IRQ_READ \
+ 		(LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
+ 
+-#define MAX_LOCKDEP_SUBCLASSES		8UL
++#define MAX_LOCKDEP_SUBCLASSES		12UL
+ 
+ /*
+  * Lock-classes are keyed via unique addresses, by embedding the
+diff --git a/include/linux/namei.h b/include/linux/namei.h
+index 99eb803..f6cdf1c 100644
+--- a/include/linux/namei.h
++++ b/include/linux/namei.h
+@@ -75,6 +75,9 @@ extern struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry
+ extern struct file *nameidata_to_filp(struct nameidata *nd, int flags);
+ extern void release_open_intent(struct nameidata *);
+ 
++extern struct dentry *lookup_hash(struct nameidata *nd);
++extern int __lookup_one_len(const char *name, struct qstr *this,
++			    struct dentry *base, int len);
+ extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
+ extern struct dentry *lookup_one_noperm(const char *, struct dentry *);
+ 
+diff --git a/include/linux/splice.h b/include/linux/splice.h
+index 528dcb9..5123bc6 100644
+--- a/include/linux/splice.h
++++ b/include/linux/splice.h
+@@ -71,4 +71,10 @@ extern ssize_t splice_to_pipe(struct pipe_inode_info *,
+ extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
+ 				      splice_direct_actor *);
+ 
++extern long vfs_splice_from(struct pipe_inode_info *pipe, struct file *out,
++			   loff_t *ppos, size_t len, unsigned int flags);
++extern long vfs_splice_to(struct file *in, loff_t *ppos,
++			 struct pipe_inode_info *pipe, size_t len,
++			 unsigned int flags);
++
+ #endif
+diff --git a/security/security.c b/security/security.c
+index c0acfa7..b8106c5 100644
+--- a/security/security.c
++++ b/security/security.c
+@@ -434,6 +434,7 @@ int security_inode_readlink(struct dentry *dentry)
+ 		return 0;
+ 	return security_ops->inode_readlink(dentry);
+ }
++EXPORT_SYMBOL(security_inode_readlink);
+ 
+ int security_inode_follow_link(struct dentry *dentry, struct nameidata *nd)
+ {
+@@ -448,6 +449,7 @@ int security_inode_permission(struct inode *inode, int mask)
+ 		return 0;
+ 	return security_ops->inode_permission(inode, mask);
+ }
++EXPORT_SYMBOL(security_inode_permission);
+ 
+ int security_inode_setattr(struct dentry *dentry, struct iattr *attr)
+ {
+aufs2 standalone patch for linux-2.6.28
+
+diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
+index 89209f0..52a7c5f 100644
+--- a/fs/ecryptfs/inode.c
++++ b/fs/ecryptfs/inode.c
+@@ -430,9 +430,6 @@ out_lock:
+ 	unlock_dir(lower_dir_dentry);
+ 	dput(lower_new_dentry);
+ 	dput(lower_old_dentry);
+-	d_drop(lower_old_dentry);
+-	d_drop(new_dentry);
+-	d_drop(old_dentry);
+ 	return rc;
+ }
+ 
+@@ -444,7 +441,10 @@ static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
+ 	struct dentry *lower_dir_dentry;
+ 
+ 	lower_dir_dentry = lock_parent(lower_dentry);
++	dget(lower_dentry);
++	atomic_inc(&lower_dentry->d_inode->i_count);
+ 	rc = vfs_unlink(lower_dir_inode, lower_dentry);
++	dput(lower_dentry);
+ 	if (rc) {
+ 		printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
+ 		goto out_unlock;
+@@ -455,6 +455,7 @@ static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
+ 	dentry->d_inode->i_ctime = dir->i_ctime;
+ 	d_drop(dentry);
+ out_unlock:
++	iput(lower_dentry->d_inode);
+ 	unlock_dir(lower_dir_dentry);
+ 	return rc;
+ }
+@@ -538,8 +539,12 @@ static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
+ 	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
+ 	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
+ 	unlock_dir(lower_dir_dentry);
+-	if (!rc)
++	if (!rc) {
++		struct inode *inode = dentry->d_inode;
++		inode->i_nlink = ecryptfs_inode_to_lower(inode)->i_nlink;
++		inode->i_ctime = dir->i_ctime;
+ 		d_drop(dentry);
++	}
+ 	dput(dentry);
+ 	return rc;
+ }
+diff -uNr test/Documentation/filesystems/aufs/README aufs2-standalone/Documentation/filesystems/aufs/README
+--- test/Documentation/filesystems/aufs/README	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/Documentation/filesystems/aufs/README	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,253 @@
++
++Aufs2 -- advanced multi layered unification filesystem version 2
++http://aufs.sf.net
++Junjiro R. Okajima
++
++
++0. Introduction
++----------------------------------------
++In the early days, aufs was entirely re-designed and re-implemented
++Unionfs Version 1.x series. After many original ideas, approaches,
++improvements and implementations, it becomes totally different from
++Unionfs while keeping the basic features.
++Recently, Unionfs Version 2.x series begin taking some of the same
++approaches to aufs1's.
++Unionfs is being developed by Professor Erez Zadok at Stony Brook
++University and his team.
++
++This version of AUFS, aufs2 has several purposes.
++- to be reviewed easily and widely.
++- to make the source files simpler and smaller by dropping several
++  original features.
++
++Through this work, I found some bad things in aufs1 source code and
++fixed them. Some of the dropped features will be reverted in the future,
++but not all I'm afraid.
++Aufs2 supports linux-2.6.27 and later. If you want older kernel version
++support, try aufs1 from CVS on SourceForge.
++
++
++1. Features
++----------------------------------------
++- unite several directories into a single virtual filesystem. The member
++  directory is called as a branch.
++- you can specify the permission flags to the branch, which are 'readonly',
++  'readwrite' and 'whiteout-able.'
++- by upper writable branch, internal copyup and whiteout, files/dirs on
++  readonly branch are modifiable logically.
++- dynamic branch manipulation, add, del.
++- etc...
++
++Also there are many enhancements in aufs1, such as:
++- keep inode number by external inode number table
++- keep the timestamps of file/dir in internal copyup operation
++- seekable directory, supporting NFS readdir.
++- support mmap(2) including /proc/PID/exe symlink, without page-copy
++- whiteout is hardlinked in order to reduce the consumption of inodes
++  on branch
++- do not copyup, nor create a whiteout when it is unnecessary
++- revert a single systemcall when an error occurs in aufs
++- remount interface instead of ioctl
++- maintain /etc/mtab by an external shell script, /sbin/mount.aufs.
++- loopback mounted filesystem as a branch
++- kernel thread for removing the dir who has a plenty of whiteouts
++- support copyup sparse file (a file which has a 'hole' in it)
++- default permission flags for branches
++- selectable permission flags for ro branch, whether whiteout can
++  exist or not
++- export via NFS.
++- support <sysfs>/fs/aufs.
++- support multiple writable branches, some policies to select one
++  among multiple writable branches.
++- a new semantics for link(2) and rename(2) to support multiple
++  writable branches.
++- a delegation of the internal branch access to support task I/O
++  accounting, which also supports Linux Security Modules (LSM) mainly
++  for Suse AppArmor.
++- nested mount, i.e. aufs as readonly no-whiteout branch of another aufs.
++- copyup-on-open or copyup-on-write
++- show-whiteout mode
++- show configuration even out of kernel tree
++- no glibc changes are required.
++- pseudo hardlink (hardlink over branches)
++- allow a direct access manually to a file on branch, e.g. bypassing aufs.
++  including NFS or remote filesystem branch.
++- and more...
++
++Currently these features are dropped temporary from this version, aufs2.
++See design/08plan.txt in detail.
++- exporting via NFS
++- test only the highest one for the directory permission (dirperm1)
++- show whiteout mode (shwh)
++- copyup on open (coo=)
++- being another aufs's readonly branch (robr)
++- statistics of aufs thread (/sys/fs/aufs/stat)
++- delegation mode (dlgt)
++- intent.open/create (file open in a single lookup)
++
++Features or just an idea in the future (see also design/*.txt),
++- reorder the branch index without del/re-add.
++- permanent xino files
++- an option for refreshing the opened files after add/del branches
++- 'move' policy for copy-up between two writable branches, after
++  checking free space.
++- remount option copy/move between two branches. (almost done)
++- O_DIRECT
++- light version, without branch manipulation. (unnecessary?)
++- copyup in userspace
++- inotify in userspace
++- xattr, acl
++
++
++2. Download
++----------------------------------------
++Kindly one of aufs user, the Center for Scientific Computing and Free
++Software (C3SL), Federal University of Parana offered me a public GIT
++tree space.
++
++There are three GIT trees, aufs2-2.6, aufs2-standalone and aufs2-util.
++While the aufs2-util is always necessary, you need either of aufs2-2.6
++or aufs2-standalone.
++
++The aufs2-2.6 tree includes the whole linux-2.6 GIT tree,
++git://git.kernel.org/.../torvalds/linux-2.6.git.
++And you cannot select CONFIG_AUFS_FS=m for this version, eg. you cannot
++build aufs2 as an externel kernel module.
++If you already have linux-2.6 GIT tree, you may want to pull and merge
++the "aufs2" branch from this tree.
++
++On the other hand, the aufs2-standalone tree has only aufs2 source files
++and a necessary patch, and you can select CONFIG_AUFS_FS=m. In other
++words, the aufs2-standalone tree is generated from aufs2-2.6 tree by,
++- extract new files and modifications.
++- generate a single patch file from modifications.
++- generate a ChangeLog file from git-log.
++- commit the files newly and no log messages. this is not git-pull.
++
++Both of aufs2-2.6 and aufs2-standalone trees have a branch whose name is
++in form of "aufs2-xx" where "xx" represents the linux kernel version,
++"linux-2.6.xx".
++
++o aufs2-2.6 tree
++$ git clone --reference /your/linux-2.6/git/tree \
++	http://git.c3sl.ufpr.br/pub/scm/aufs/aufs2-2.6.git \
++	aufs2-2.6.git
++- if you don't have linux-2.6 GIT tree, then remove "--reference ..."
++$ cd aufs2-2.6.git
++$ git checkout origin/aufs2-xx	# for instance, aufs2-27 for linux-2.6.27
++				# aufs2 (no -xx) for the latest -rc version.
++
++o aufs2-standalone tree
++$ git clone http://git.c3sl.ufpr.br/pub/scm/aufs/aufs2-standalone.git \
++	aufs2-standalone.git
++$ cd aufs2-standalone.git
++$ git checkout origin/aufs2-xx	# for instance, aufs2-27 for linux-2.6.27
++- apply "aufs2-standalone.patch" to your kernel source files.
++
++o aufs2-util tree
++$ git clone http://git.c3sl.ufpr.br/pub/scm/aufs/aufs2-util.git \
++	aufs2-util.git
++$ cd aufs2-util.git
++- no particular tag/branch currently.
++
++
++3. Configuration and Compilation
++----------------------------------------
++For aufs2-2.6 tree,
++- enable CONFIG_EXPERIMENTAL and CONFIG_AUFS_FS.
++- set other aufs configurations if necessary.
++
++For aufs2-standalone tree,
++- enable CONFIG_EXPERIMENTAL and CONFIG_AUFS_FS, you can select =m.
++- edit fs/aufs/config.mk and set other aufs configurations if necessary.
++
++And then,
++- build your kernel (or a module) by "make"
++- install it and reboot your system
++- read README in aufs2-util, build and install it
++
++
++4. Usage
++----------------------------------------
++At first, make sure aufs2-util are installed, and please read the aufs
++manual, ./Documentation/filesystems/aufs/aufs.5.
++$ man -l aufs.5
++
++And then,
++$ mkdir /tmp/rw /tmp/aufs
++# mount -t aufs -o br=/tmp/rw:${HOME}=ro none /tmp/aufs
++
++Here is another example. The result is equivalent.
++# mount -t aufs -o br=/tmp/rw:${HOME} none /tmp/aufs
++  Or
++# mount -t aufs -o br:/tmp/rw none /tmp/aufs
++# mount -o remount,append:${HOME} /tmp/aufs
++
++Then, you can see whole tree of your home dir through /tmp/aufs. If
++you modify a file under /tmp/aufs, the one on your home directory is
++not affected, instead the same named file will be newly created under
++/tmp/rw. And all of your modification to a file will be applied to
++the one under /tmp/rw. This is called the file based Copy on Write
++(COW) method.
++Aufs mount options are described in aufs.5.
++
++Additionally, there are some sample usages of aufs which are a
++diskless system with network booting, and LiveCD over NFS.
++See sample dir in CVS tree on SourceForge.
++
++
++5. Contact
++----------------------------------------
++When you have any problems or strange behaviour in aufs, please let me
++know with:
++- /proc/mounts (instead of the output of mount(8))
++- /sys/fs/aufs/* (if you have them)
++- /sys/module/aufs/*
++- linux kernel version
++  if your kernel is not plain, for example modified by distributor,
++  the url where i can download its source is necessary too.
++- aufs version which was printed at loading the module or booting the
++  system, instead of the date you downloaded.
++- configuration (define/undefine CONFIG_AUFS_xxx)
++- kernel configuration or /proc/config.gz (if you have it)
++- behaviour which you think to be incorrect
++- actual operation, reproducible one is better
++- mailto: aufs-users at lists.sourceforge.net
++
++Usually, I don't watch the Public Areas(Bugs, Support Requests, Patches,
++and Feature Requests) on SourceForge. Please join and write to
++aufs-users ML.
++
++
++6. Acknowledgements
++----------------------------------------
++Thanks to everyone who have tried and are using aufs, whoever
++have reported a bug or any feedback.
++
++Especially donors:
++Tomas Matejicek(slax.org) made a donation (much more than once).
++Dai Itasaka made a donation (2007/8).
++Chuck Smith made a donation (2008/4, 10 and 12).
++Henk Schoneveld made a donation (2008/9).
++Chih-Wei Huang, ASUS, CTC donated Eee PC 4G (2008/10).
++Francois Dupoux made a donation (2008/11).
++Bruno Cesar Ribas and Luis Carlos Erpen de Bona, C3SL serves public GIT
++tree (2009/2).
++William Grant made a donation (2009/3).
++
++Thank you very much.
++Donations are always, including future donations, very important and
++helpful for me to keep on developing aufs.
++
++
++7.
++----------------------------------------
++If you are an experienced user, no explanation is needed. Aufs is
++just a linux filesystem.
++
++
++Enjoy!
++
++# Local variables: ;
++# mode: text;
++# End: ;
+diff -uNr test/Documentation/filesystems/aufs/aufs.5 aufs2-standalone/Documentation/filesystems/aufs/aufs.5
+--- test/Documentation/filesystems/aufs/aufs.5	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/Documentation/filesystems/aufs/aufs.5	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,1514 @@
++.ds AUFS_VERSION aufs2-base6
++.ds AUFS_XINO_FNAME .aufs.xino
++.ds AUFS_XINO_DEFPATH /tmp/.aufs.xino
++.ds AUFS_DIRWH_DEF 3
++.ds AUFS_WH_PFX .wh.
++.ds AUFS_WH_PFX_LEN 4
++.ds AUFS_WKQ_NAME aufsd
++.ds AUFS_NWKQ_DEF 4
++.ds AUFS_WH_DIROPQ .wh..wh..opq
++.ds AUFS_WH_BASE .wh..wh.aufs
++.ds AUFS_WH_PLINKDIR .wh..wh.plnk
++.ds AUFS_BRANCH_MAX 127
++.ds AUFS_MFS_SECOND_DEF 30
++.\".so aufs.tmac
++.
++.eo
++.de TQ
++.br
++.ns
++.TP \$1
++..
++.de Bu
++.IP \(bu 4
++..
++.ec
++.\" end of macro definitions
++.
++.\" ----------------------------------------------------------------------
++.TH aufs 5 \*[AUFS_VERSION] Linux "Linux Aufs User\[aq]s Manual"
++.SH NAME
++aufs \- another unionfs. version \*[AUFS_VERSION]
++
++.\" ----------------------------------------------------------------------
++.SH DESCRIPTION
++Aufs is a stackable unification filesystem such as Unionfs, which unifies
++several directories and provides a merged single directory.
++In the early days, aufs was entirely re-designed and re-implemented
++Unionfs Version 1.x series. After
++many original ideas, approaches and improvements, it
++becomes totally different from Unionfs while keeping the basic features.
++See Unionfs Version 1.x series for the basic features.
++Recently, Unionfs Version 2.x series begin taking some of same
++approaches to aufs\[aq]s.
++
++.\" ----------------------------------------------------------------------
++.SH MOUNT OPTIONS
++At mount-time, the order of interpreting options is,
++.RS
++.Bu
++simple flags, except xino/noxino and udba=inotify
++.Bu
++branches
++.Bu
++xino/noxino
++.Bu
++udba=inotify
++.RE
++
++At remount-time,
++the options are interpreted in the given order,
++e.g. left to right.
++.RS
++.Bu
++create or remove
++whiteout-base(\*[AUFS_WH_BASE]) and
++whplink-dir(\*[AUFS_WH_PLINKDIR]) if necessary
++.RE
++.
++.TP
++.B br:BRANCH[:BRANCH ...] (dirs=BRANCH[:BRANCH ...])
++Adds new branches.
++(cf. Branch Syntax).
++
++Aufs rejects the branch which is an ancestor or a descendant of anther
++branch. It is called overlapped. When the branch is loopback-mounted
++directory, aufs also checks the source fs-image file of loopback
++device. If the source file is a descendant of another branch, it will
++be rejected too.
++
++After mounting aufs or adding a branch, if you move a branch under
++another branch and make it descendant of anther branch, aufs will not
++work correctly.
++.
++.TP
++.B [ add | ins ]:index:BRANCH
++Adds a new branch.
++The index begins with 0.
++Aufs creates
++whiteout-base(\*[AUFS_WH_BASE]) and
++whplink-dir(\*[AUFS_WH_PLINKDIR]) if necessary.
++
++If there is the same named file on the lower branch (larger index),
++aufs will hide the lower file.
++You can only see the highest file.
++You will be confused if the added branch has whiteouts (including
++diropq), they may or may not hide the lower entries.
++.\" It is recommended to make sure that the added branch has no whiteout.
++
++If a process have once mapped a file by mmap(2) with MAP_SHARED
++and the same named file exists on the lower branch,
++the process still refers the file on the lower(hidden)
++branch after adding the branch.
++If you want to update the contents of a process address space after
++adding, you need to restart your process or open/mmap the file again.
++.\" Usually, such files are executables or shared libraries.
++(cf. Branch Syntax).
++.
++.TP
++.B del:dir
++Removes a branch.
++Aufs does not remove
++whiteout-base(\*[AUFS_WH_BASE]) and
++whplink-dir(\*[AUFS_WH_PLINKDIR]) automatically.
++For example, when you add a RO branch which was unified as RW, you
++will see whiteout-base or whplink-dir on the added RO branch.
++
++If a process is referencing the file/directory on the deleting branch
++(by open, mmap, current working directory, etc.), aufs will return an
++error EBUSY.
++.
++.TP
++.B mod:BRANCH
++Modifies the permission flags of the branch.
++Aufs creates or removes
++whiteout-base(\*[AUFS_WH_BASE]) and/or
++whplink-dir(\*[AUFS_WH_PLINKDIR]) if necessary.
++
++If the branch permission is been changing \[oq]rw\[cq] to \[oq]ro\[cq], and a process
++is mapping a file by mmap(2)
++.\" with MAP_SHARED
++on the branch, the process may or may not
++be able to modify its mapped memory region after modifying branch
++permission flags.
++(cf. Branch Syntax).
++.
++.TP
++.B append:BRANCH
++equivalent to \[oq]add:(last index + 1):BRANCH\[cq].
++(cf. Branch Syntax).
++.
++.TP
++.B prepend:BRANCH
++equivalent to \[oq]add:0:BRANCH.\[cq]
++(cf. Branch Syntax).
++.
++.TP
++.B xino=filename
++Use external inode number bitmap and translation table.
++It is set to
++<FirstWritableBranch>/\*[AUFS_XINO_FNAME] by default, or
++\*[AUFS_XINO_DEFPATH].
++Comma character in filename is not allowed.
++
++The files are created per an aufs and per a branch filesystem, and
++unlinked. So you
++cannot find this file, but it exists and is read/written frequently by
++aufs.
++(cf. External Inode Number Bitmap, Translation Table).
++.
++.TP
++.B noxino
++Stop using external inode number bitmap and translation table.
++
++If you use this option,
++Some applications will not work correctly.
++.\" And pseudo link feature will not work after the inode cache is
++.\" shrunk.
++(cf. External Inode Number Bitmap, Translation Table).
++.
++.TP
++.B trunc_xib
++Truncate the external inode number bitmap file. The truncation is done
++automatically when you delete a branch unless you do not specify
++\[oq]notrunc_xib\[cq] option.
++(cf. External Inode Number Bitmap, Translation Table).
++.
++.TP
++.B notrunc_xib
++Stop truncating the external inode number bitmap file when you delete
++a branch.
++(cf. External Inode Number Bitmap, Translation Table).
++.
++.TP
++.B create_policy | create=CREATE_POLICY
++.TQ
++.B copyup_policy | copyup | cpup=COPYUP_POLICY
++Policies to select one among multiple writable branches. The default
++values are \[oq]create=tdp\[cq] and \[oq]cpup=tdp\[cq].
++link(2) and rename(2) systemcalls have an exception. In aufs, they
++try keeping their operations in the branch where the source exists.
++(cf. Policies to Select One among Multiple Writable Branches).
++.
++.TP
++.B verbose | v
++Print some information.
++Currently, it is only busy file (or inode) at deleting a branch.
++.
++.TP
++.B noverbose | quiet | q | silent
++Disable \[oq]verbose\[cq] option.
++This is default value.
++.
++.TP
++.B sum
++df(1)/statfs(2) returns the total number of blocks and inodes of
++all branches.
++Note that there are cases that systemcalls may return ENOSPC, even if
++df(1)/statfs(2) shows that aufs has some free space/inode.
++.
++.TP
++.B nosum
++Disable \[oq]sum\[cq] option.
++This is default value.
++.
++.TP
++.B dirwh=N
++Watermark to remove a dir actually at rmdir(2) and rename(2).
++
++If the target dir which is being removed or renamed (destination dir)
++has a huge number of whiteouts, i.e. the dir is empty logically but
++physically, the cost to remove/rename the single
++dir may be very high.
++It is
++required to unlink all of whiteouts internally before issuing
++rmdir/rename to the branch.
++To reduce the cost of single systemcall,
++aufs renames the target dir to a whiteout-ed temporary name and
++invokes a pre-created
++kernel thread to remove whiteout-ed children and the target dir.
++The rmdir/rename systemcall returns just after kicking the thread.
++
++When the number of whiteout-ed children is less than the value of
++dirwh, aufs remove them in a single systemcall instead of passing
++another thread.
++This value is ignored when the branch is NFS.
++The default value is \*[AUFS_DIRWH_DEF].
++.
++.TP
++.B plink
++.TQ
++.B noplink
++Specifies to use \[oq]pseudo link\[cq] feature or not.
++The default is \[oq]plink\[cq] which means use this feature.
++(cf. Pseudo Link)
++.
++.TP
++.B clean_plink
++Removes all pseudo-links in memory.
++In order to make pseudo-link permanent, use
++\[oq]auplink\[cq] utility just before one of these operations,
++unmounting aufs,
++using \[oq]ro\[cq] or \[oq]noplink\[cq] mount option,
++deleting a branch from aufs,
++adding a branch into aufs,
++or changing your writable branch as readonly.
++If you installed both of /sbin/mount.aufs and /sbin/umount.aufs, and your
++mount(8) and umount(8) support them,
++\[oq]auplink\[cq] utility will be executed automatically and flush pseudo-links.
++(cf. Pseudo Link)
++.
++.TP
++.B udba=none | reval | inotify
++Specifies the level of UDBA (User\[aq]s Direct Branch Access) test.
++(cf. User\[aq]s Direct Branch Access and Inotify Limitation).
++.
++.TP
++.B diropq=whiteouted | w | always | a
++Specifies whether mkdir(2) and rename(2) dir case make the created directory
++\[oq]opaque\[cq] or not.
++In other words, to create \[oq]\*[AUFS_WH_DIROPQ]\[cq] under the created or renamed
++directory, or not to create.
++When you specify diropq=w or diropq=whiteouted, aufs will not create
++it if the
++directory was not whiteouted or opaqued. If the directory was whiteouted
++or opaqued, the created or renamed directory will be opaque.
++When you specify diropq=a or diropq==always, aufs will always create
++it regardless
++the directory was whiteouted/opaqued or not.
++The default value is diropq=w, it means not to create when it is unnecessary.
++If you define CONFIG_AUFS_COMPAT at aufs compiling time, the default will be
++diropq=a.
++You need to consider this option if you are planning to add a branch later
++since \[oq]diropq\[cq] affects the same named directory on the added branch.
++.
++.TP
++.B warn_perm
++.TQ
++.B nowarn_perm
++Adding a branch, aufs will issue a warning about uid/gid/permission of
++the adding branch directory,
++when they differ from the existing branch\[aq]s. This difference may or
++may not impose a security risk.
++If you are sure that there is no problem and want to stop the warning,
++use \[oq]nowarn_perm\[cq] option.
++The default is \[oq]warn_perm\[cq] (cf. DIAGNOSTICS).
++
++.\" ----------------------------------------------------------------------
++.SH Module Parameters
++.TP
++.B nwkq=N
++The number of kernel thread named \*[AUFS_WKQ_NAME].
++
++Those threads stay in the system while the aufs module is loaded,
++and handle the special I/O requests from aufs.
++The default value is \*[AUFS_NWKQ_DEF].
++
++The special I/O requests from aufs include a part of copy-up, lookup,
++directory handling, pseudo-link, xino file operations and the
++delegated access to branches.
++For example, Unix filesystems allow you to rmdir(2) which has no write
++permission bit, if its parent directory has write permission bit. In aufs, the
++removing directory may or may not have whiteout or \[oq]dir opaque\[cq] mark as its
++child. And aufs needs to unlink(2) them before rmdir(2).
++Therefore aufs delegates the actual unlink(2) and rmdir(2) to another kernel
++thread which has been created already and has a superuser privilege.
++
++If you enable CONFIG_SYSFS, you can check this value through
++<sysfs>/module/aufs/parameters/nwkq.
++
++.
++.TP
++.B brs=1 | 0
++Specifies to use the branch path data file under sysfs or not.
++
++If the number of your branches is large or their path is long
++and you meet the limitation of mount(8) ro /etc/mtab, you need to
++enable CONFIG_SYSFS and set aufs module parameter brs=1.
++If your linux version is linux\-2.6.24 and earlier, you need to enable
++CONFIG_AUFS_SYSAUFS too.
++
++When this parameter is set as 1, aufs does not show \[oq]br:\[cq] (or dirs=)
++mount option through /proc/mounts, and /sbin/mount.aufs does not put it
++to /etc/mtab. So you can keep yourself from the page limitation of
++mount(8) or /etc/mtab.
++Aufs shows branch paths through <sysfs>/fs/aufs/si_XXX/brNNN.
++Actually the file under sysfs has also a size limitation, but I don\[aq]t
++think it is harmful.
++
++The default is brs=0, which means <sysfs>/fs/aufs/si_XXX/brNNN does not exist
++and \[oq]br:\[cq] option will appear in /proc/mounts, and /etc/mtab if you
++install /sbin/mount.aufs.
++If you did not enable CONFIG_AUFS_SYSAUFS (for
++linux\-2.6.24 and earlier), this parameter will be
++ignored.
++
++There is one more side effect in setting 1 to this parameter.
++If you rename your branch, the branch path written in /etc/mtab will be
++obsoleted and the future remount will meet some error due to the
++unmatched parameters (Remember that mount(8) may take the options from
++/etc/mtab and pass them to the systemcall).
++If you set 1, /etc/mtab will not hold the branch path and you will not
++meet such trouble. On the other hand, the entires for the
++branch path under sysfs are generated dynamically. So it must not be obsoleted.
++But I don\[aq]t think users want to rename branches so often.
++.
++.TP
++.B sysrq=key
++Specifies MagicSysRq key for debugging aufs.
++You need to enable both of CONFIG_MAGIC_SYSRQ and CONFIG_AUFS_DEBUG.
++If your linux version is linux\-2.6.24 and earlier, you need to enable
++CONFIG_AUFS_SYSAUFS too.
++Currently this is for developers only.
++The default is \[oq]a\[cq].
++
++.\" ----------------------------------------------------------------------
++.SH Branch Syntax
++.TP
++.B dir_path[ =permission [ + attribute ] ]
++.TQ
++.B permission := rw | ro | rr
++.TQ
++.B attribute := wh | nolwh
++dir_path is a directory path.
++The keyword after \[oq]dir_path=\[cq] is a
++permission flags for that branch.
++Comma, colon and the permission flags string (including \[oq]=\[cq])in the path
++are not allowed.
++
++Any filesystem can be a branch, except aufs, sysfs, procfs and unionfs.
++If you specify such filesystems as an aufs branch, aufs will return an error
++saying it is unsupported.
++
++Cramfs in linux stable release has strange inodes and it makes aufs
++confused. For example,
++.nf
++$ mkdir -p w/d1 w/d2
++$ > w/z1
++$ > w/z2
++$ mkcramfs w cramfs
++$ sudo mount -t cramfs -o ro,loop cramfs /mnt
++$ find /mnt -ls
++    76    1 drwxr-xr-x   1 jro      232            64 Jan  1  1970 /mnt
++     1    1 drwxr-xr-x   1 jro      232             0 Jan  1  1970 /mnt/d1
++     1    1 drwxr-xr-x   1 jro      232             0 Jan  1  1970 /mnt/d2
++     1    1 -rw-r--r--   1 jro      232             0 Jan  1  1970 /mnt/z1
++     1    1 -rw-r--r--   1 jro      232             0 Jan  1  1970 /mnt/z2
++.fi
++
++All these two directories and two files have the same inode with one
++as their link count. Aufs cannot handle such inode correctly.
++Currently, aufs involves a tiny workaround for such inodes. But some
++applications may not work correctly since aufs inode number for such
++inode will change silently.
++If you do not have any empty files, empty directories or special files,
++inodes on cramfs will be all fine.
++
++A branch should not be shared as the writable branch between multiple
++aufs. A readonly branch can be shared.
++
++The maximum number of branches is configurable at compile time.
++The current value is \*[AUFS_BRANCH_MAX] which depends upon
++configuration.
++
++When an unknown permission or attribute is given, aufs sets ro to that
++branch silently.
++
++.SS Permission
++.
++.TP
++.B rw
++Readable and writable branch. Set as default for the first branch.
++If the branch filesystem is mounted as readonly, you cannot set it \[oq]rw.\[cq]
++.\" A filesystem which does not support link(2) and i_op\->setattr(), for
++.\" example FAT, will not be used as the writable branch.
++.
++.TP
++.B ro
++Readonly branch and it has no whiteouts on it.
++Set as default for all branches except the first one. Aufs never issue
++both of write operation and lookup operation for whiteout to this branch.
++.
++.TP
++.B rr
++Real readonly branch, special case of \[oq]ro\[cq], for natively readonly
++branch. Assuming the branch is natively readonly, aufs can optimize
++some internal operation. For example, if you specify \[oq]udba=inotify\[cq]
++option, aufs does not set inotify for the things on rr branch.
++Set by default for a branch whose fs-type is either \[oq]iso9660\[cq],
++\[oq]cramfs\[cq] or \[oq]romfs\[cq].
++
++When your branch exists on slower device and you have some
++capacity on your hdd, you may want to try ulobdev tool in ULOOP sample.
++It can cache the contents of the real devices on another faster device,
++so you will be able to get the better access performance.
++The ulobdev tool is for a generic block device, and the ulohttp is for a
++filesystem image on http server.
++If you want to spin down your hdd to save the
++battery life or something, then you may want to use ulobdev to save the
++access to the hdd, too.
++See $AufsCVS/sample/uloop in detail.
++
++.SS Attribute
++.
++.TP
++.B wh
++Readonly branch and it has/might have whiteouts on it.
++Aufs never issue write operation to this branch, but lookup for whiteout.
++Use this as \[oq]<branch_dir>=ro+wh\[cq].
++.
++.TP
++.B nolwh
++Usually, aufs creates a whiteout as a hardlink on a writable
++branch. This attributes prohibits aufs to create the hardlinked
++whiteout, including the source file of all hardlinked whiteout
++(\*[AUFS_WH_BASE].)
++If you do not like a hardlink, or your writable branch does not support
++link(2), then use this attribute.
++But I am afraid a filesystem which does not support link(2) natively
++will fail in other place such as copy-up.
++Use this as \[oq]<branch_dir>=rw+nolwh\[cq].
++Also you may want to try \[oq]noplink\[cq] mount option, while it is not recommended.
++
++.\" .SS FUSE as a branch
++.\" A FUSE branch needs special attention.
++.\" The struct fuse_operations has a statfs operation. It is OK, but the
++.\" parameter is struct statvfs* instead of struct statfs*. So almost
++.\" all user\-space implementaion will call statvfs(3)/fstatvfs(3) instead of
++.\" statfs(2)/fstatfs(2).
++.\" In glibc, [f]statvfs(3) issues [f]statfs(2), open(2)/read(2) for
++.\" /proc/mounts,
++.\" and stat(2) for the mountpoint. With this situation, a FUSE branch will
++.\" cause a deadlock in creating something in aufs. Here is a sample
++.\" scenario,
++.\" .\" .RS
++.\" .\" .IN -10
++.\" .Bu
++.\" create/modify a file just under the aufs root dir.
++.\" .Bu
++.\" aufs aquires a write\-lock for the parent directory, ie. the root dir.
++.\" .Bu
++.\" A library function or fuse internal may call statfs for a fuse branch.
++.\" The create=mfs mode in aufs will surely call statfs for each writable
++.\" branches.
++.\" .Bu
++.\" FUSE in kernel\-space converts and redirects the statfs request to the
++.\" user\-space.
++.\" .Bu
++.\" the user\-space statfs handler will call [f]statvfs(3).
++.\" .Bu
++.\" the [f]statvfs(3) in glibc will access /proc/mounts and issue
++.\" stat(2) for the mountpoint. But those require a read\-lock for the aufs
++.\" root directory.
++.\" .Bu
++.\" Then a deadlock occurs.
++.\" .\" .RE 1
++.\" .\" .IN
++.\" 
++.\" In order to avoid this deadlock, I would suggest not to call
++.\" [f]statvfs(3) from fuse. Here is a sample code to do this.
++.\" .nf
++.\" struct statvfs stvfs;
++.\" 
++.\" main()
++.\" {
++.\" 	statvfs(..., &stvfs)
++.\" 	or
++.\" 	fstatvfs(..., &stvfs)
++.\" 	stvfs.f_fsid = 0
++.\" }
++.\" 
++.\" statfs_handler(const char *path, struct statvfs *arg)
++.\" {
++.\" 	struct statfs stfs
++.\" 
++.\" 	memcpy(arg, &stvfs, sizeof(stvfs))
++.\" 
++.\" 	statfs(..., &stfs)
++.\" 	or
++.\" 	fstatfs(..., &stfs)
++.\" 
++.\" 	arg->f_bfree = stfs.f_bfree
++.\" 	arg->f_bavail = stfs.f_bavail
++.\" 	arg->f_ffree = stfs.f_ffree
++.\" 	arg->f_favail = /* any value */
++.\" }
++.\" .fi
++
++.\" ----------------------------------------------------------------------
++.SH External Inode Number Bitmap, Translation Table (xino)
++Aufs uses one external bitmap file and one external inode number
++translation table files per an aufs and per a branch
++filesystem by default.
++The bitmap is for recycling aufs inode number
++and the others
++are a table for converting an inode number on a branch to
++an aufs inode number. The default path
++is \[oq]first writable branch\[cq]/\*[AUFS_XINO_FNAME].
++If there is no writable branch, the
++default path
++will be \*[AUFS_XINO_DEFPATH].
++.\" A user who executes mount(8) needs the privilege to create xino
++.\" file.
++
++Those files are always opened and read/write by aufs frequently.
++If your writable branch is on flash memory device, it is recommended
++to put xino files on other than flash memory by specifying \[oq]xino=\[cq]
++mount option.
++
++The
++maximum file size of the bitmap is, basically, the amount of the
++number of all the files on all branches divided by 8 (the number of
++bits in a byte).
++For example, on a 4KB page size system, if you have 32,768 (or
++2,599,968) files in aufs world,
++then the maximum file size of the bitmap is 4KB (or 320KB).
++
++The
++maximum file size of the table will
++be \[oq]max inode number on the branch x size of an inode number\[cq].
++For example in 32bit environment,
++
++.nf
++$ df -i /branch_fs
++/dev/hda14           2599968  203127 2396841    8% /branch_fs
++.fi
++
++and /branch_fs is an branch of the aufs. When the inode number is
++assigned contiguously (without \[oq]hole\[cq]), the maximum xino file size for
++/branch_fs will be 2,599,968 x 4 bytes = about 10 MB. But it might not be
++allocated all of disk blocks.
++When the inode number is assigned discontinuously, the maximum size of
++xino file will be the largest inode number on a branch x 4 bytes.
++Additionally, the file size is limited to LLONG_MAX or the s_maxbytes
++in filesystem\[aq]s superblock (s_maxbytes may be smaller than
++LLONG_MAX). So the
++support-able largest inode number on a branch is less than
++2305843009213693950 (LLONG_MAX/4\-1).
++This is the current limitation of aufs.
++On 64bit environment, this limitation becomes more strict and the
++supported largest inode number is less than LLONG_MAX/8\-1.
++
++The xino files are always hidden, i.e. removed. So you cannot
++do \[oq]ls \-l xino_file\[cq].
++If you enable CONFIG_SYSFS, you can check these information through
++<sysfs>/fs/aufs/<si_id>/xino (for linux\-2.6.24 and earlier, you
++need to enable CONFIG_AUFS_SYSAUFS too).
++The first line in <sysfs>/fs/aufs/<si_id>/xino (and xigen) shows the
++information of the bitmap file, in the format of,
++
++.nf
++<blocks>x<block size> <file size>
++.fi
++
++Note that a filesystem usually has a
++feature called pre-allocation, which means a number of
++blocks are allocated automatically, and then deallocated
++silently when the filesystem thinks they are unnecessary.
++You do not have to be surprised the sudden changes of the number of
++blocks, when your filesystem which xino files are placed supports the
++pre-allocation feature.
++
++The rests are hidden xino file information in the format of,
++
++.nf
++<branch index>: <file count>, <blocks>x<block size> <file size>
++.fi
++
++If the file count is larger than 1, it means some of your branches are
++on the same filesystem and the xino file is shared by them.
++Note that the file size may not be equal to the actual consuming blocks
++since xino file is a sparse file, i.e. a hole in a file which does not
++consume any disk blocks.
++
++Once you unmount aufs, the xino files for that aufs are totally gone.
++It means that the inode number is not permanent.
++
++The xino files should be created on the filesystem except NFS.
++If your first writable branch is NFS, you will need to specify xino
++file path other than NFS.
++Also if you are going to remove the branch where xino files exist or
++change the branch permission to readonly, you need to use xino option
++before del/mod the branch.
++
++The bitmap file can be truncated.
++For example, if you delete a branch which has huge number of files,
++many inode numbers will be recycled and the bitmap will be truncated
++to smaller size. Aufs does this automatically when a branch is
++deleted.
++You can truncate it anytime you like if you specify \[oq]trunc_xib\[cq] mount
++option. But when the accessed inode number was not deleted, nothing
++will be truncated.
++If you do not want to truncate it (it may be slow) when you delete a
++branch, specify \[oq]notrunc_xib\[cq] after \[oq]del\[cq] mount option.
++
++If you do not want to use xino, use noxino mount option. Use this
++option with care, since the inode number may be changed silently and
++unexpectedly anytime.
++For example,
++rmdir failure, recursive chmod/chown/etc to a large and deep directory
++or anything else.
++And some applications will not work correctly.
++.\" When the inode number has been changed, your system
++.\" can be crazy.
++If you want to change the xino default path, use xino mount option.
++
++After you add branches, the persistence of inode number may not be
++guaranteed.
++At remount time, cached but unused inodes are discarded.
++And the newly appeared inode may have different inode number at the
++next access time. The inodes in use have the persistent inode number.
++
++When aufs assigned an inode number to a file, and if you create the
++same named file on the upper branch directly, then the next time you
++access the file, aufs may assign another inode number to the file even
++if you use xino option.
++Some applications may treat the file whose inode number has been
++changed as totally different file.
++
++.\" ----------------------------------------------------------------------
++.SH Pseudo Link (hardlink over branches)
++Aufs supports \[oq]pseudo link\[cq] which is a logical hard-link over
++branches (cf. ln(1) and link(2)).
++In other words, a copied-up file by link(2) and a copied-up file which was
++hard-linked on a readonly branch filesystem.
++
++When you have files named fileA and fileB which are
++hardlinked on a readonly branch, if you write something into fileA,
++aufs copies-up fileA to a writable branch, and write(2) the originally
++requested thing to the copied-up fileA. On the writable branch,
++fileA is not hardlinked.
++But aufs remembers it was hardlinked, and handles fileB as if it existed
++on the writable branch, by referencing  fileA\[aq]s inode on the writable
++branch as fileB\[aq]s inode.
++
++Once you unmount aufs, the plink info for that aufs kept in memory are totally
++gone.
++It means that the pseudo-link is not permanent.
++If you want to make plink permanent, try \[oq]auplink\[cq] utility just before
++one of these operations,
++unmounting your aufs,
++using \[oq]ro\[cq] or \[oq]noplink\[cq] mount option,
++deleting a branch from aufs,
++adding a branch into aufs,
++or changing your writable branch to readonly.
++
++This utility will reproduces all real hardlinks on a writable branch by linking
++them, and removes pseudo-link info in memory and temporary link on the
++writable branch.
++Since this utility access your branches directly, you cannot hide them by
++\[oq]mount \-\-bind /tmp /branch\[cq] or something.
++
++If you are willing to rebuild your aufs with the same branches later, you
++should use auplink utility before you umount your aufs.
++If you installed both of /sbin/mount.aufs and /sbin/umount.aufs, and your
++mount(8) and umount(8) support them,
++\[oq]auplink\[cq] utility will be executed automatically and flush pseudo-links.
++
++.nf
++# auplink /your/aufs/root flush
++# umount /your/aufs/root
++or
++# auplink /your/aufs/root flush
++# mount -o remount,mod:/your/writable/branch=ro /your/aufs/root
++or
++# auplink /your/aufs/root flush
++# mount -o remount,noplink /your/aufs/root
++or
++# auplink /your/aufs/root flush
++# mount -o remount,del:/your/aufs/branch /your/aufs/root
++or
++# auplink /your/aufs/root flush
++# mount -o remount,append:/your/aufs/branch /your/aufs/root
++.fi
++
++The plinks are kept both in memory and on disk. When they consumes too much
++resources on your system, you can use the \[oq]auplink\[cq] utility at anytime and
++throw away the unnecessary pseudo-links in safe.
++
++Additionally, the \[oq]auplink\[cq] utility is very useful for some security reasons.
++For example, when you have a directory whose permission flags
++are 0700, and a file who is 0644 under the 0700 directory. Usually,
++all files under the 0700 directory are private and no one else can see
++the file. But when the directory is 0711 and someone else knows the 0644
++filename, he can read the file.
++
++Basically, aufs pseudo-link feature creates a temporary link under the
++directory whose owner is root and the permission flags are 0700.
++But when the writable branch is NFS, aufs sets 0711 to the directory.
++When the 0644 file is pseudo-linked, the temporary link, of course the
++contents of the file is totally equivalent, will be created under the
++0711 directory. The filename will be generated by its inode number.
++While it is hard to know the generated filename, someone else may try peeping
++the temporary pseudo-linked file by his software tool which may try the name
++from one to MAX_INT or something.
++In this case, the 0644 file will be read unexpectedly.
++I am afraid that leaving the temporary pseudo-links can be a security hole.
++It makes sense to execute \[oq]auplink /your/aufs/root flush\[cq]
++periodically, when your writable branch is NFS.
++
++When your writable branch is not NFS, or all users are careful enough to set 0600
++to their private files, you do not have to worry about this issue.
++
++If you do not want this feature, use \[oq]noplink\[cq] mount option.
++
++.SS The behaviours of plink and noplink
++This sample shows that the \[oq]f_src_linked2\[cq] with \[oq]noplink\[cq] option cannot follow
++the link.
++
++.nf
++none on /dev/shm/u type aufs (rw,xino=/dev/shm/rw/.aufs.xino,br:/dev/shm/rw=rw:/dev/shm/ro=ro)
++$ ls -li ../r?/f_src_linked* ./f_src_linked* ./copied
++ls: ./copied: No such file or directory
++15 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ../ro/f_src_linked
++15 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ../ro/f_src_linked2
++22 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ./f_src_linked
++22 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ./f_src_linked2
++$ echo abc >> f_src_linked
++$ cp f_src_linked copied
++$ ls -li ../r?/f_src_linked* ./f_src_linked* ./copied
++15 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ../ro/f_src_linked
++15 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ../ro/f_src_linked2
++36 -rw-r--r--  2 jro jro 6 Dec 22 11:03 ../rw/f_src_linked
++53 -rw-r--r--  1 jro jro 6 Dec 22 11:03 ./copied
++22 -rw-r--r--  2 jro jro 6 Dec 22 11:03 ./f_src_linked
++22 -rw-r--r--  2 jro jro 6 Dec 22 11:03 ./f_src_linked2
++$ cmp copied f_src_linked2
++$
++
++none on /dev/shm/u type aufs (rw,xino=/dev/shm/rw/.aufs.xino,noplink,br:/dev/shm/rw=rw:/dev/shm/ro=ro)
++$ ls -li ../r?/f_src_linked* ./f_src_linked* ./copied
++ls: ./copied: No such file or directory
++17 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ../ro/f_src_linked
++17 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ../ro/f_src_linked2
++23 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ./f_src_linked
++23 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ./f_src_linked2
++$ echo abc >> f_src_linked
++$ cp f_src_linked copied
++$ ls -li ../r?/f_src_linked* ./f_src_linked* ./copied
++17 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ../ro/f_src_linked
++17 -rw-r--r--  2 jro jro 2 Dec 22 11:03 ../ro/f_src_linked2
++36 -rw-r--r--  1 jro jro 6 Dec 22 11:03 ../rw/f_src_linked
++53 -rw-r--r--  1 jro jro 6 Dec 22 11:03 ./copied
++23 -rw-r--r--  2 jro jro 6 Dec 22 11:03 ./f_src_linked
++23 -rw-r--r--  2 jro jro 6 Dec 22 11:03 ./f_src_linked2
++$ cmp copied f_src_linked2
++cmp: EOF on f_src_linked2
++$
++.fi
++
++.\"
++.\" If you add/del a branch, or link/unlink the pseudo-linked
++.\" file on a branch
++.\" directly, aufs cannot keep the correct link count, but the status of
++.\" \[oq]pseudo-linked.\[cq]
++.\" Those files may or may not keep the file data after you unlink the
++.\" file on the branch directly, especially the case of your branch is
++.\" NFS.
++
++If you add a branch which has fileA or fileB, aufs does not follow the
++pseudo link. The file on the added branch has no relation to the same
++named file(s) on the lower branch(es).
++If you use noxino mount option, pseudo link will not work after the
++kernel shrinks the inode cache.
++
++This feature will not work for squashfs before version 3.2 since its
++inode is tricky.
++When the inode is hardlinked, squashfs inodes has the same inode
++number and correct link count, but the inode memory object is
++different. Squashfs inodes (before v3.2) are generated for each, even
++they are hardlinked.
++
++.\" ----------------------------------------------------------------------
++.SH User\[aq]s Direct Branch Access (UDBA)
++UDBA means a modification to a branch filesystem manually or directly,
++e.g. bypassing aufs.
++While aufs is designed and implemented to be safe after UDBA,
++it can make yourself and your aufs confused. And some information like
++aufs inode will be incorrect.
++For example, if you rename a file on a branch directly, the file on
++aufs may
++or may not be accessible through both of old and new name.
++Because aufs caches various information about the files on
++branches. And the cache still remains after UDBA.
++
++Aufs has a mount option named \[oq]udba\[cq] which specifies the test level at
++access time whether UDBA was happened or not.
++.
++.TP
++.B udba=none
++Aufs trusts the dentry and the inode cache on the system, and never
++test about UDBA. With this option, aufs runs fastest, but it may show
++you incorrect data.
++Additionally, if you often modify a branch
++directly, aufs will not be able to trace the changes of inodes on the
++branch. It can be a cause of wrong behaviour, deadlock or anything else.
++
++It is recommended to use this option only when you are sure that
++nobody access a file on a branch.
++It might be difficult for you to achieve real \[oq]no UDBA\[cq] world when you
++cannot stop your users doing \[oq]find / \-ls\[cq] or something.
++If you really want to forbid all of your users to UDBA, here is a trick
++for it.
++With this trick, users cannot see the
++branches directly and aufs runs with no problem, except \[oq]auplink\[cq] utility.
++But if you are not familiar with aufs, this trick may make
++yourself confused.
++
++.nf
++# d=/tmp/.aufs.hide
++# mkdir $d
++# for i in $branches_you_want_to_hide
++> do
++>	mount -n --bind $d $i
++> done
++.fi
++
++When you unmount the aufs, delete/modify the branch by remount, or you
++want to show the hidden branches again, unmount the bound
++/tmp/.aufs.hide.
++
++.nf
++# umount -n $branches_you_want_to_unbound
++.fi
++
++If you use FUSE filesystem as an aufs branch which supports hardlink,
++you should not set this option, since FUSE makes inode objects for
++each hardlinks (at least in linux\-2.6.23). When your FUSE filesystem
++maintains them at link/unlinking, it is equivalent
++to \[oq]direct branch access\[cq] for aufs.
++
++.
++.TP
++.B udba=reval
++Aufs tests only the existence of the file which existed. If
++the existed file was removed on the branch directly, aufs
++discard the cache about the file and
++re-lookup it. So the data will be updated.
++This test is at minimum level to keep the performance and ensure the
++existence of a file.
++This is default and aufs runs still fast.
++
++This rule leads to some unexpected situation, but I hope it is
++harmless. Those are totally depends upon cache. Here are just a few
++examples.
++.
++.RS
++.Bu
++If the file is cached as negative or
++not-existed, aufs does not test it. And the file is still handled as
++negative after a user created the file on a branch directly. If the
++file is not cached, aufs will lookup normally and find the file.
++.
++.Bu
++When the file is cached as positive or existed, and a user created the
++same named file directly on the upper branch. Aufs detects the cached
++inode of the file is still existing and will show you the old (cached)
++file which is on the lower branch.
++.
++.Bu
++When the file is cached as positive or existed, and a user renamed the
++file by rename(2) directly. Aufs detects the inode of the file is
++still existing. You may or may not see both of the old and new files.
++Todo: If aufs also tests the name, we can detect this case.
++.RE
++
++If your outer modification (UDBA) is rare and you can ignore the
++temporary and minor differences between virtual aufs world and real
++branch filesystem, then try this mount option.
++.
++.TP
++.B udba=inotify
++Aufs sets `inotify' to all the accessed directories on its branches
++and receives the event about the dir and its children. It consumes
++resources, cpu and memory. And I am afraid that the performance will be
++hurt, but it is most strict test level.
++There are some limitations of linux inotify, see also Inotify
++Limitation.
++So it is recommended to leave udba default option usually, and set it
++to inotify by remount when you need it.
++
++When a user accesses the file which was notified UDBA before, the cached data
++about the file will be discarded and aufs re-lookup it. So the data will
++be updated.
++When an error condition occurs between UDBA and aufs operation, aufs
++will return an error, including EIO.
++To use this option, you need linux\-2.6.18 and later, and need to
++enable CONFIG_INOTIFY and CONFIG_AUFS_UDBA_INOTIFY.
++
++To rename/rmdir a directory on a branch directory may reveal the same named
++directory on the lower branch. Aufs tries re-lookuping the renamed
++directory and the revealed directory and assigning different inode
++number to them. But the inode number including their children can be a
++problem. The inode numbers will be changed silently, and
++aufs may produce a warning. If you rename a directory repeatedly and
++reveal/hide the lower directory, then aufs may confuse their inode
++numbers too. It depends upon the system cache.
++
++When you make a directory in aufs and mount other filesystem on it,
++the directory in aufs cannot be removed expectedly because it is a
++mount point. But the same named directory on the writable branch can
++be removed, if someone wants. It is just an empty directory, instead
++of a mount point.
++Aufs cannot stop such direct rmdir, but produces a warning about it.
++
++If the pseudo-linked file is hardlinked or unlinked on the branch
++directly, its inode link count in aufs may be incorrect. It is
++recommended to flush the psuedo-links by auplink script.
++
++.\" ----------------------------------------------------------------------
++.SH Linux Inotify Limitation
++Unfortunately, current inotify (linux\-2.6.18) has some limitations,
++and aufs must derive it.
++
++.SS IN_ATTRIB, updating atime
++When a file/dir on a branch is accessed directly, the inode atime (access
++time, cf. stat(2)) may or may not be updated. In some cases, inotify
++does not fire this event. So the aufs inode atime may remain old.
++
++.SS IN_ATTRIB, updating nlink
++When the link count of a file on a branch is incremented by link(2)
++directly,
++inotify fires IN_CREATE to the parent
++directory, but IN_ATTRIB to the file. So the aufs inode nlink may
++remain old.
++
++.SS IN_DELETE, removing file on NFS
++When a file on a NFS branch is deleted directly, inotify may or may
++not fire
++IN_DELETE event. It depends upon the status of dentry
++(DCACHE_NFSFS_RENAMED flag).
++In this case, the file on aufs seems still exists. Aufs and any user can see
++the file.
++
++.SS IN_IGNORED, deleted rename target
++When a file/dir on a branch is unlinked by rename(2) directly, inotify
++fires IN_IGNORED which means the inode is deleted. Actually, in some
++cases, the inode survives. For example, the rename target is linked or
++opened. In this case, inotify watch set by aufs is removed by VFS and
++inotify.
++And aufs cannot receive the events anymore. So aufs may show you
++incorrect data about the file/dir.
++
++.\" ----------------------------------------------------------------------
++.SH Copy On Write, or aufs internal copyup and copydown
++Every stackable filesystem which implements copy\-on\-write supports the
++copyup feature. The feature is to copy a file/dir from the lower branch
++to the upper internally. When you have one readonly branch and one
++upper writable branch, and you append a string to a file which exists on
++the readonly branch, then aufs will copy the file from the readonly
++branch to the writable branch with its directory hierarchy. It means one
++write(2) involves several logical/internal mkdir(2), creat(2), read(2),
++write(2) and close(2) systemcalls
++before the actual expected write(2) is performed. Sometimes it may take
++a long time, particulary when the file is very large.
++If CONFIG_AUFS_DEBUG is enabled, aufs produces a message saying `copying
++a large file.\[aq]
++
++You may see the message when you change the xino file path or
++truncate the xino/xib files. Sometimes those files can be large and may
++take a long time to handle them.
++
++.\" ----------------------------------------------------------------------
++.SH Policies to Select One among Multiple Writable Branches
++Aufs has some policies to select one among multiple writable branches
++when you are going to write/modify something. There are two kinds of
++policies, one is for newly create something and the other is for
++internal copy-up.
++You can select them by specifying mount option \[oq]create=CREATE_POLICY\[cq]
++or \[oq]cpup=COPYUP_POLICY.\[cq]
++These policies have no meaning when you have only one writable
++branch. If there is some meaning, it must hurt the performance.
++
++.SS Exceptions for Policies
++In every cases below, even if the policy says that the branch where a
++new file should be created is /rw2, the file will be created on /rw1.
++.
++.Bu
++If there is a readonly branch with \[oq]wh\[cq] attribute above the
++policy-selected branch and the parent dir is marked as opaque,
++or the target (creating) file is whiteouted on the ro+wh branch, then
++the policy will be ignored and the target file will be created on the
++nearest upper writable branch than the ro+wh branch.
++.RS
++.nf
++/aufs = /rw1 + /ro+wh/diropq + /rw2
++/aufs = /rw1 + /ro+wh/wh.tgt + /rw2
++.fi
++.RE
++.
++.Bu
++If there is a writable branch above the policy-selected branch and the
++parent dir is marked as opaque or the target file is whiteouted on the
++branch, then the policy will be ignored and the target file will be
++created on the highest one among the upper writable branches who has
++diropq or whiteout. In case of whiteout, aufs removes it as usual.
++.RS
++.nf
++/aufs = /rw1/diropq + /rw2
++/aufs = /rw1/wh.tgt + /rw2
++.fi
++.RE
++.
++.Bu
++link(2) and rename(2) systemcalls are exceptions in every policy.
++They try selecting the branch where the source exists as possible since
++copyup a large file will take long time. If it can\[aq]t be, ie. the
++branch where the source exists is readonly, then they will follow the
++copyup policy.
++.
++.Bu
++There is an exception for rename(2) when the target exists.
++If the rename target exists, aufs compares the index of the branches
++where the source and the target are existing and selects the higher
++one. If the selected branch is readonly, then aufs follows the copyup
++policy.
++
++.SS Policies for Creating
++.
++.TP
++.B create=tdp | top\-down\-parent
++Selects the highest writable branch where the parent dir exists. If
++the parent dir does not exist on a writable branch, then the internal
++copyup will happen. The policy for this copyup is always \[oq]bottom-up.\[cq]
++This is the default policy.
++.
++.TP
++.B create=rr | round\-robin
++Selects a writable branch in round robin. When you have two writable
++branches and creates 10 new files, 5 files will be created for each
++branch.
++mkdir(2) systemcall is an exception. When you create 10 new directories,
++all are created on the same branch.
++.
++.TP
++.B create=mfs[:second] | most\-free\-space[:second]
++Selects a writable branch which has most free space. In order to keep
++the performance, you can specify the duration (\[oq]second\[cq]) which makes
++aufs hold the index of last selected writable branch until the
++specified seconds expires. The first time you create something in aufs
++after the specified seconds expired, aufs checks the amount of free
++space of all writable branches by internal statfs call
++and the held branch index will be updated.
++The default value is \*[AUFS_MFS_SECOND_DEF] seconds.
++.
++.TP
++.B create=mfsrr:low[:second]
++Selects a writable branch in most-free-space mode first, and then
++round-robin mode. If the selected branch has less free space than the
++specified value \[oq]low\[cq] in bytes, then aufs re-tries in round-robin mode.
++.\" \[oq]G\[cq], \[oq]M\[cq] and \[oq]K\[cq] (case insensitive) can be followed after \[oq]low.\[cq] Or
++Try an arithmetic expansion of shell which is defined by POSIX.
++For example, $((10 * 1024 * 1024)) for 10M.
++You can also specify the duration (\[oq]second\[cq]) which is equivalent to
++the \[oq]mfs\[cq] mode.
++.
++.TP
++.B create=pmfs[:second]
++Selects a writable branch where the parent dir exists, such as tdp
++mode. When the parent dir exists on multiple writable branches, aufs
++selects the one which has most free space, such as mfs mode.
++
++.SS Policies for Copy-Up
++.
++.TP
++.B cpup=tdp | top\-down\-parent
++Equivalent to the same named policy for create.
++This is the default policy.
++.
++.TP
++.B cpup=bup | bottom\-up\-parent
++Selects the writable branch where the parent dir exists and the branch
++is nearest upper one from the copyup-source.
++.
++.TP
++.B cpup=bu | bottom\-up
++Selects the nearest upper writable branch from the copyup-source,
++regardless the existence of the parent dir.
++
++.\" ----------------------------------------------------------------------
++.SH Dentry and Inode Caches
++If you want to clear caches on your system, there are several tricks
++for that. If your system ram is low,
++try \[oq]find /large/dir \-ls > /dev/null\[cq].
++It will read many inodes and dentries and cache them. Then old caches will be
++discarded.
++But when you have large ram or you do not have such large
++directory, it is not effective.
++
++If you want to discard cache within a certain filesystem,
++try \[oq]mount \-o remount /your/mntpnt\[cq]. Some filesystem may return an error of
++EINVAL or something, but VFS discards the unused dentry/inode caches on the
++specified filesystem.
++
++.\" ----------------------------------------------------------------------
++.SH Compatible/Incompatible with Unionfs Version 1.x Series
++If you compile aufs with \-DCONFIG_AUFS_COMPAT, dirs= option and =nfsro
++branch permission flag are available. They are interpreted as
++br: option and =ro flags respectively.
++ \[oq]debug\[cq], \[oq]delete\[cq], \[oq]imap\[cq] options are ignored silently. When you
++compile aufs without \-DCONFIG_AUFS_COMPAT, these three options are
++also ignored, but a warning message is issued.
++
++Ignoring \[oq]delete\[cq] option, and to keep filesystem consistency, aufs tries
++writing something to only one branch in a single systemcall. It means
++aufs may copyup even if the copyup-src branch is specified as writable.
++For example, you have two writable branches and a large regular file
++on the lower writable branch. When you issue rename(2) to the file on aufs,
++aufs may copyup it to the upper writable branch.
++If this behaviour is not what you want, then you should rename(2) it
++on the lower branch directly.
++
++And there is a simple shell
++script \[oq]unionctl\[cq] under sample subdirectory, which is compatible with
++unionctl(8) in
++Unionfs Version 1.x series, except \-\-query action.
++This script executes mount(8) with \[oq]remount\[cq] option and uses
++add/del/mod aufs mount options.
++If you are familiar with Unionfs Version 1.x series and want to use unionctl(8), you can
++try this script instead of using mount \-o remount,... directly.
++Aufs does not support ioctl(2) interface.
++This script is highly depending upon mount(8) in
++util\-linux\-2.12p package, and you need to mount /proc to use this script.
++If your mount(8) version differs, you can try modifying this
++script. It is very easy.
++The unionctl script is just for a sample usage of aufs remount
++interface.
++
++Aufs uses the external inode number bitmap and translation table by
++default.
++
++The default branch permission for the first branch is \[oq]rw\[cq], and the
++rest is \[oq]ro.\[cq]
++
++The whiteout is for hiding files on lower branches. Also it is applied
++to stop readdir going lower branches.
++The latter case is called \[oq]opaque directory.\[cq] Any
++whiteout is an empty file, it means whiteout is just an mark.
++In the case of hiding lower files, the name of whiteout is
++\[oq]\*[AUFS_WH_PFX]<filename>.\[cq]
++And in the case of stopping readdir, the name is
++\[oq]\*[AUFS_WH_PFX]\*[AUFS_WH_PFX].opq\[cq] or
++\[oq]\*[AUFS_WH_PFX]__dir_opaque.\[cq] The name depends upon your compile
++configuration
++CONFIG_AUFS_COMPAT.
++.\" All of newly created or renamed directory will be opaque.
++All whiteouts are hardlinked,
++including \[oq]<writable branch top dir>/\*[AUFS_WH_BASE].\[cq]
++
++The hardlink on an ordinary (disk based) filesystem does not
++consume inode resource newly. But in linux tmpfs, the number of free
++inodes will be decremented by link(2). It is recommended to specify
++nr_inodes option to your tmpfs if you meet ENOSPC. Use this option
++after checking by \[oq]df \-i.\[cq]
++
++When you rmdir or rename-to the dir who has a number of whiteouts,
++aufs rename the dir to the temporary whiteouted-name like
++\[oq]\*[AUFS_WH_PFX]<dir>.<random hex>.\[cq] Then remove it after actual operation.
++cf. mount option \[oq]dirwh.\[cq]
++
++.\" ----------------------------------------------------------------------
++.SH Incompatible with an Ordinary Filesystem
++stat(2) returns the inode info from the first existence inode among
++the branches, except the directory link count.
++Aufs computes the directory link count larger than the exact value usually, in
++order to keep UNIX filesystem semantics, or in order to shut find(1) mouth up.
++The size of a directory may be wrong too, but it has to do no harm.
++The timestamp of a directory will not be updated when a file is
++created or removed under it, and it was done on a lower branch.
++
++The test for permission bits has two cases. One is for a directory,
++and the other is for a non-directory. In the case of a directory, aufs
++checks the permission bits of all existing directories. It means you
++need the correct privilege for the directories including the lower
++branches.
++The test for a non-directory is more simple. It checks only the
++topmost inode.
++
++statfs(2) returns the information of the first branch info except
++namelen when \[oq]nosum\[cq] is specified (the default). The namelen is
++decreased by the whiteout prefix length. And the block size may differ
++from st_blksize which is obtained by stat(2).
++
++Remember, seekdir(3) and telldir(3) are not defined in POSIX. They may
++not work as you expect. Try rewinddir(3) or re-open the dir.
++
++The whiteout prefix (\*[AUFS_WH_PFX]) is reserved on all branches. Users should
++not handle the filename begins with this prefix.
++In order to future whiteout, the maxmum filename length is limited by
++the longest value \- \*[AUFS_WH_PFX_LEN]. It may be a violation of POSIX.
++
++If you dislike the difference between the aufs entries in /etc/mtab
++and /proc/mounts, and if you are using mount(8) in util\-linux package,
++then try ./mount.aufs utility. Copy the script to /sbin/mount.aufs.
++This simple utility tries updating
++/etc/mtab. If you do not care about /etc/mtab, you can ignore this
++utility.
++Remember this utility is highly depending upon mount(8) in
++util\-linux\-2.12p package, and you need to mount /proc.
++
++Since aufs uses its own inode and dentry, your system may cache huge
++number of inodes and dentries. It can be as twice as all of the files
++in your union.
++It means that unmounting or remounting readonly at shutdown time may
++take a long time, since mount(2) in VFS tries freeing all of the cache
++on the target filesystem.
++
++When you open a directory, aufs will open several directories
++internally.
++It means you may reach the limit of the number of file descriptor.
++And when the lower directory cannot be opened, aufs will close all the
++opened upper directories and return an error.
++
++The sub-mount under the branch
++of local filesystem
++is ignored.
++For example, if you have mount another filesystem on
++/branch/another/mntpnt, the files under \[oq]mntpnt\[cq] will be ignored by aufs.
++It is recommended to mount the sub-mount under the mounted aufs.
++For example,
++
++.nf
++# sudo mount /dev/sdaXX /ro_branch
++# d=another/mntpnt
++# sudo mount /dev/sdbXX /ro_branch/$d
++# mkdir -p /rw_branch/$d
++# sudo mount -t aufs -o br:/rw_branch:/ro_branch none /aufs
++# sudo mount -t aufs -o br:/rw_branch/${d}:/ro_branch/${d} none /aufs/another/$d
++.fi
++
++There are several characters which are not allowed to use in a branch
++directory path and xino filename. See detail in Branch Syntax and Mount
++Option.
++
++The file-lock which means fcntl(2) with F_SETLK, F_SETLKW or F_GETLK, flock(2)
++and lockf(3), is applied to virtual aufs file only, not to the file on a
++branch. It means you can break the lock by accessing a branch directly.
++TODO: check \[oq]security\[cq] to hook locks, as inotify does.
++
++The I/O to the named pipe or local socket are not handled by aufs, even
++if it exists in aufs. After the reader and the writer established their
++connection if the pipe/socket are copied-up, they keep using the old one
++instead of the copied-up one.
++
++The fsync(2) and fdatasync(2) systemcalls return 0 which means success, even
++if the given file descriptor is not opened for writing.
++I am afraid this behaviour may violate some standards. Checking the
++behaviour of fsync(2) on ext2, aufs decided to return success.
++
++If you want to use disk-quota, you should set it up to your writable
++branch since aufs does not have its own block device.
++
++When your aufs is the root directory of your system, and your system
++tells you some of the filesystem were not unmounted cleanly, try these
++procedure when you shutdown your system.
++.nf
++# mount -no remount,ro /
++# for i in $writable_branches
++# do mount -no remount,ro $i
++# done
++.fi
++If your xino file is on a hard drive, you also need to specify
++\[oq]noxino\[cq] option or \[oq]xino=/your/tmpfs/xino\[cq] at remounting root
++directory.
++
++To rename(2) directory may return EXDEV even if both of src and tgt
++are on the same aufs. When the rename-src dir exists on multiple
++branches and the lower dir has child(ren), aufs has to copyup all his
++children. It can be recursive copyup. Current aufs does not support
++such huge copyup operation at one time in kernel space, instead
++produces a warning and returns EXDEV.
++Generally, mv(1) detects this error and tries mkdir(2) and
++rename(2) or copy/unlink recursively. So the result is harmless.
++If your application which issues rename(2) for a directory does not
++support EXDEV, it will not work on aufs.
++Also this specification is applied to the case when the src directroy
++exists on the lower readonly branch and it has child(ren).
++
++If a sudden accident such like a power failure happens during aufs is
++performing, and regular fsck for branch filesystems is completed after
++the disaster, you need to extra fsck for aufs writable branches. It is
++necessary to check whether the whiteout remains incorrectly or not,
++eg. the real filename and the whiteout for it under the same parent
++directory. If such whiteout remains, aufs cannot handle the file
++correctly.
++To check the consistency from the aufs\[aq] point of view, you can use a
++simple shell script called /sbin/auchk. Its purpose is a fsck tool for
++aufs, and it checks the illegal whiteout, the remained
++pseudo-links and the remained aufs-temp files. If they are found, the
++utility reports you and asks whether to delete or not.
++It is recommended to execute /sbin/auchk for every writable branch
++filesystem before mouting aufs if the system experienced crash.
++
++
++.\" ----------------------------------------------------------------------
++.SH EXAMPLES
++The mount options are interpreted from left to right at remount-time.
++These examples
++shows how the options are handled. (assuming /sbin/mount.aufs was
++installed)
++
++.nf
++# mount -v -t aufs br:/day0:/base none /u
++none on /u type aufs (rw,xino=/day0/.aufs.xino,br:/day0=rw:/base=ro)
++# mount -v -o remount,\\
++	prepend:/day1,\\
++	xino=/day1/xino,\\
++	mod:/day0=ro,\\
++	del:/day0 \\
++	/u
++none on /u type aufs (rw,xino=/day1/xino,br:/day1=rw:/base=ro)
++.fi
++
++.nf
++# mount -t aufs br:/rw none /u
++# mount -o remount,append:/ro /u
++different uid/gid/permission, /ro
++# mount -o remount,del:/ro /u
++# mount -o remount,nowarn_perm,append:/ro /u
++#
++(there is no warning)
++.fi
++
++.\" If you want to expand your filesystem size, aufs may help you by
++.\" adding an writable branch. Since aufs supports multiple writable
++.\" branches, the old writable branch can be being writable, if you want.
++.\" In this example, any modifications to the files under /ro branch will
++.\" be copied-up to /new, but modifications to the files under /rw branch
++.\" will not.
++.\" And the next example shows the modifications to the files under /rw branch
++.\" will be copied-up to /new/a.
++.\"
++.\" Todo: test multiple writable branches policy. cpup=nearest, cpup=exist_parent.
++.\"
++.\" .nf
++.\" # mount -v -t aufs br:/rw:/ro none /u
++.\" none on /u type aufs (rw,xino=/rw/.aufs.xino,br:/rw=rw:/ro=ro)
++.\" # mkfs /new
++.\" # mount -v -o remount,add:1:/new=rw /u
++.\" none on /u type aufs (rw,xino=/rw/.aufs.xino,br:/rw=rw:/new=rw:/ro=ro)
++.\" .fi
++.\"
++.\" .nf
++.\" # mount -v -t aufs br:/rw:/ro none /u
++.\" none on /u type aufs (rw,xino=/rw/.aufs.xino,br:/rw=rw:/ro=ro)
++.\" # mkfs /new
++.\" # mkdir /new/a new/b
++.\" # mount -v -o remount,add:1:/new/b=rw,prepend:/new/a,mod:/rw=ro /u
++.\" none on /u type aufs (rw,xino=/rw/.aufs.xino,br:/new/a=rw:/rw=ro:/new/b=rw:/ro=ro)
++.\" .fi
++
++When you use aufs as root filesystem, it is recommended to consider to
++exclude some directories. For example, /tmp and /var/log are not need
++to stack in many cases. They do not usually need to copyup or to whiteout.
++Also the swapfile on aufs (a regular file, not a block device) is not
++supported.
++In order to exclude the specific dir from aufs, try bind mounting.
++
++And there is a good sample which is for network booted diskless machines. See
++sample/ in detail.
++
++.\" ----------------------------------------------------------------------
++.SH DIAGNOSTICS
++When you add a branch to your union, aufs may warn you about the
++privilege or security of the branch, which is the permission bits,
++owner and group of the top directory of the branch.
++For example, when your upper writable branch has a world writable top
++directory,
++a malicious user can create any files on the writable branch directly,
++like copyup and modify manually. I am afraid it can be a security
++issue.
++
++When you mount or remount your union without \-o ro common mount option
++and without writable branch, aufs will warn you that the first branch
++should be writable.
++
++.\" It is discouraged to set both of \[oq]udba\[cq] and \[oq]noxino\[cq] mount options. In
++.\" this case the inode number under aufs will always be changed and may
++.\" reach the end of inode number which is a maximum of unsigned long. If
++.\" the inode number reaches the end, aufs will return EIO repeatedly.
++
++When you set udba other than inotify and change something on your
++branch filesystem directly, later aufs may detect some mismatches to
++its cache. If it is a critical mismatch, aufs returns EIO.
++
++When an error occurs in aufs, aufs prints the kernel message with
++\[oq]errno.\[cq] The priority of the message (log level) is ERR or WARNING which
++depends upon the message itself.
++You can convert the \[oq]errno\[cq] into the error message by perror(3),
++strerror(3) or something.
++For example, the \[oq]errno\[cq] in the message \[oq]I/O Error, write failed (\-28)\[cq]
++is 28 which means ENOSPC or \[oq]No space left on device.\[cq]
++
++.\" .SH Current Limitation
++.
++.\" ----------------------------------------------------------------------
++.\" SYNOPSIS
++.\" briefly describes the command or function\[aq]s interface.  For  commands,  this
++.\" shows the syntax of the command and its arguments (including options); bold-
++.\" face is used for as-is text and italics are  used  to  indicate  replaceable
++.\" arguments. Brackets ([]) surround optional arguments, vertical bars (|) sep-
++.\" arate choices, and ellipses (...) can be repeated.  For functions, it  shows
++.\" any required data declarations or #include directives, followed by the func-
++.\" tion declaration.
++.
++.\" DESCRIPTION
++.\" gives an explanation of what the command, function, or format does.  Discuss
++.\" how  it  interacts  with  files  and standard input, and what it produces on
++.\" standard output  or  standard  error.   Omit  internals  and  implementation
++.\" details  unless  they\[aq]re critical for understanding the interface.  Describe
++.\" the usual case; for information on options  use  the  OPTIONS  section.   If
++.\" there  is some kind of input grammar or complex set of subcommands, consider
++.\" describing them in a separate USAGE section (and just place an  overview  in
++.\" the DESCRIPTION section).
++.
++.\" RETURN VALUE
++.\" gives a list of the values the library routine will return to the caller and
++.\" the conditions that cause these values to be returned.
++.
++.\" EXIT STATUS
++.\" lists the possible exit status values or a program and the  conditions  that
++.\" cause these values to be returned.
++.
++.\" USAGE
++.\" describes the grammar of any sublanguage this implements.
++.
++.\" FILES
++.\" lists  the  files the program or function uses, such as configuration files,
++.\" startup files, and files the program directly operates on.   Give  the  full
++.\" pathname  of  these  files,  and  use the installation process to modify the
++.\" directory part to match user preferences.  For many  programs,  the  default
++.\" installation  location is in /usr/local, so your base manual page should use
++.\" /usr/local as the base.
++.
++.\" ENVIRONMENT
++.\" lists all environment variables that affect your program or function and how
++.\" they affect it.
++.
++.\" SECURITY
++.\" discusses security issues and implications.  Warn  about  configurations  or
++.\" environments  that should be avoided, commands that may have security impli-
++.\" cations, and so on, especially if they aren\[aq]t obvious.  Discussing  security
++.\" in  a  separate section isn\[aq]t necessary; if it\[aq]s easier to understand, place
++.\" security information in the other sections (such as the DESCRIPTION or USAGE
++.\" section).  However, please include security information somewhere!
++.
++.\" CONFORMING TO
++.\" describes any standards or conventions this implements.
++.
++.\" NOTES
++.\" provides miscellaneous notes.
++.
++.\" BUGS
++.\" lists  limitations,  known defects or inconveniences, and other questionable
++.\" activities.
++
++.SH COPYRIGHT
++Copyright \(co 2005\-2009 Junjiro R. Okajima
++
++.SH AUTHOR
++Junjiro R. Okajima
++
++.\" SEE ALSO
++.\" lists  related  man  pages in alphabetical order, possibly followed by other
++.\" related pages or documents.  Conventionally this is the last section.
+diff -uNr test/Documentation/filesystems/aufs/design/01intro.txt aufs2-standalone/Documentation/filesystems/aufs/design/01intro.txt
+--- test/Documentation/filesystems/aufs/design/01intro.txt	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/Documentation/filesystems/aufs/design/01intro.txt	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,128 @@
++
++# Copyright (C) 2005-2009 Junjiro R. Okajima
++# 
++# This program is free software; you can redistribute it and/or modify
++# it under the terms of the GNU General Public License as published by
++# the Free Software Foundation; either version 2 of the License, or
++# (at your option) any later version.
++
++Introduction
++----------------------------------------
++
++aufs [ei ju: ef es] | [a u f s]
++1. abbrev. for "advanced multi-layered unification filesystem".
++2. abbrev. for "another unionfs".
++3. abbrev. for "auf das" in German which means "on the" in English.
++   Ex. "Butter aufs Brot"(G) means "butter onto bread"(E).
++   But "Filesystem aufs Filesystem" is hard to understand.
++
++AUFS is a filesystem with features:
++- multi layered stackable unification filesystem, the member directory
++  is called as a branch.
++- branch permission and attribute, 'readonly', 'real-readonly',
++  'readwrite', 'whiteout-able', 'link-able whiteout' and their
++  combination.
++- internal "file copy-on-write".
++- logical deletion, whiteout.
++- dynamic branch manipulation, adding, deleting and changing permission.
++- allow bypassing aufs, user's direct branch access.
++- external inode number translation table and bitmap which maintains the
++  persistent aufs inode number.
++- seekable directory, including NFS readdir.
++- file mapping, mmap and sharing pages.
++- pseudo-link, hardlink over branches.
++- loopback mounted filesystem as a branch.
++- several policies to select one among multiple writable branches.
++- revert a single systemcall when an error occurs in aufs.
++- and more...
++
++
++Multi Layered Stackable Unification Filesystem
++----------------------------------------------------------------------
++Most people already knows what it is.
++It is a filesystem which unifies several directories and provides a
++merged single directory. When users access a file, the access will be
++passed/re-directed/converted (sorry, I am not sure which English word is
++correct) to the real file on the member filesystem. The member
++filesystem is called 'lower filesystem' or 'branch' and has a mode
++'readonly' and 'readwrite.' And the deletion for a file on the lower
++readonly branch is handled by creating 'whiteout' on the upper writable
++branch.
++
++On LKML, there have been discussions about UnionMount (Jan Blunck and
++Bharata B Rao) and Unionfs (Erez Zadok). They took different approaches
++to implement the merged-view.
++The former tries putting it into VFS, and the latter implements as a
++separate filesystem.
++(If I misunderstand about these implementations, please let me know and
++I shall correct it. Because it is a long time ago when I read their
++source files last time).
++UnionMount's approach will be able to small, but may be hard to share
++branches between several UnionMount since the whiteout in it is
++implemented in the inode on branch filesystem and always
++shared. According to Bharata's post, readdir does not seems to be
++finished yet.
++Unionfs has a longer history. When I started implementing a stacking filesystem
++(Aug 2005), it already existed. It has virtual super_block, inode,
++dentry and file objects and they have an array pointing lower same kind
++objects. After contributing many patches for Unionfs, I re-started my
++project AUFS (Jun 2006).
++
++In AUFS, the structure of filesystem resembles to Unionfs, but I
++implemented my own ideas, approaches and enhancements and it became
++totally different one.
++
++
++Several characters/aspects of aufs
++----------------------------------------------------------------------
++
++Aufs has several characters or aspects.
++1. a filesystem, callee of VFS helper
++2. sub-VFS, caller of VFS helper for branches
++3. a virtual filesystem which maintains persistent inode number
++4. reader/writer of files on branches such like an application
++
++1. Caller of VFS Helper
++As an ordinary linux filesystem, aufs is a callee of VFS. For instance,
++unlink(2) from an application reaches sys_unlink() kernel function and
++then vfs_unlink() is called. vfs_unlink() is one of VFS helper and it
++calls filesystem specific unlink operation. Actually aufs implements the
++unlink operation but it behaves like a redirector.
++
++2. Caller of VFS Helper for Branches
++aufs_unlink() passes the unlink request to the branch filesystem as if
++it were called from VFS. So the called unlink operation of the branch
++filesystem acts as usual. As a caller of VFS helper, aufs should handle
++every necessary pre/post operation for the branch filesystem.
++- acquire the lock for the parent dir on a branch
++- lookup in a branch
++- revalidate dentry on a branch
++- mnt_want_write() for a branch
++- vfs_unlink() for a branch
++- mnt_drop_write() for a branch
++- release the lock on a branch
++
++3. Persistent Inode Number
++One of the most important issue for a filesystem is to maintain inode
++numbers. This is particularly important to support exporting a
++filesystem via NFS. Aufs is a virtual filesystem which doesn't have a
++backend block device for its own. But some storage is necessary to
++maintain inode number. It may be a large space and may not suit to keep
++in memory. Aufs rents some space from its first writable branch
++filesystem (by default) and creates file(s) on it. These files are
++created by aufs internally and removed soon (currently) keeping opened.
++Note: Because these files are removed, they are totally gone after
++      unmounting aufs. It means the inode numbers are not persistent
++      across unmount or reboot. I have a plan to make them really
++      persistent which will be important for aufs on NFS server.
++
++4. Read/Write Files Internally (copy-on-write)
++Because a branch can be readonly, when you write a file on it, aufs will
++"copy-up" it to the upper writable branch internally. And then write the
++originally requested thing to the file. Generally kernel doesn't
++open/read/write file actively. In aufs, even a single write may cause a
++internal "file copy". This behaviour is very similar to cp(1) command.
++
++Some people may think it is better to pass such work to user space
++helper, instead of doing in kernel space. Actually I am still thinking
++about it. But currently I have implemented it in kernel space.
+diff -uNr test/Documentation/filesystems/aufs/design/02struct.txt aufs2-standalone/Documentation/filesystems/aufs/design/02struct.txt
+--- test/Documentation/filesystems/aufs/design/02struct.txt	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/Documentation/filesystems/aufs/design/02struct.txt	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,205 @@
++
++# Copyright (C) 2005-2009 Junjiro R. Okajima
++# 
++# This program is free software; you can redistribute it and/or modify
++# it under the terms of the GNU General Public License as published by
++# the Free Software Foundation; either version 2 of the License, or
++# (at your option) any later version.
++
++Basic Aufs Internal Structure
++
++Superblock/Inode/Dentry/File Objects
++----------------------------------------------------------------------
++As like an ordinary filesystem, aufs has its own
++superblock/inode/dentry/file objects. All these objects have a
++dynamically allocated array and store the same kind of pointers to the
++lower filesystem, branch.
++For example, when you build a union with one readwrite branch and one
++readonly, mounted /au, /rw and /ro respectively.
++- /au = /rw + /ro
++- /ro/fileA exists but /rw/fileA
++
++Aufs lookup operation finds /ro/fileA and gets dentry for that. These
++pointers are stored in a aufs dentry. The array in aufs dentry will be,
++- [0] = NULL
++- [1] = /ro/fileA
++
++This style of an array is essentially same to the aufs
++superblock/inode/dentry/file objects.
++
++Because aufs supports manipulating branches, ie. add/delete/change
++dynamically, these objects has its own generation. When branches are
++changed, the generation in aufs superblock is incremented. And a
++generation in other object are compared when it is accessed.
++When a generation in other objects are obsoleted, aufs refreshes the
++internal array.
++
++
++Superblock
++----------------------------------------------------------------------
++Additionally aufs superblock has some data for policies to select one
++among multiple writable branches, XIB files, pseudo-links and kobject.
++See below in detail.
++About the policies which supports copy-down a directory, see policy.txt
++too.
++
++
++Branch and XINO(External Inode Number Translation Table)
++----------------------------------------------------------------------
++Every branch has its own xino (external inode number translation table)
++file. The xino file is created and unlinked by aufs internally. When two
++members of a union exist on the same filesystem, they share the single
++xino file.
++The struct of a xino file is simple, just a sequence of aufs inode
++numbers which is indexed by the lower inode number.
++In the above sample, assume the inode number of /ro/fileA is i111 and
++aufs assigns the inode number i999 for fileA. Then aufs writes 999 as
++4(8) bytes at 111 * 4(8) bytes offset in the xino file.
++
++When the inode numbers are not contiguous, the xino file will be sparse
++which has a hole in it and doesn't consume as much disk space as it
++might appear. If your branch filesystem consumes disk space for such
++holes, then you should specify 'xino=' option at mounting aufs.
++
++Also a writable branch has three kinds of "whiteout bases". All these
++are existed when the branch is joined to aufs and the names are
++whiteout-ed doubly, so that users will never see their names in aufs
++hierarchy.
++1. a regular file which will be linked to all whiteouts.
++2. a directory to store a pseudo-link.
++3. a directory to store an "orphan-ed" file temporary.
++
++1. Whiteout Base
++   When you remove a file on a readonly branch, aufs handles it as a
++   logical deletion and creates a whiteout on the upper writable branch
++   as a hardlink of this file in order not to consume inode on the
++   writable branch.
++2. Pseudo-link Dir
++   See below, Pseudo-link.
++3. Step-Parent Dir
++   When "fileC" exists on the lower readonly branch only and it is
++   opened and removed with its parent dir, and then user writes
++   something into it, then aufs copies-up fileC to this
++   directory. Because there is no other dir to store fileC. After
++   creating a file under this dir, the file is unlinked.
++
++Because aufs supports manipulating branches, ie. add/delete/change
++dynamically, a branch has its own id. When the branch order changes, aufs
++finds the new index by searching the branch id.
++
++
++Pseudo-link
++----------------------------------------------------------------------
++Assume "fileA" exists on the lower readonly branch only and it is
++hardlinked to "fileB" on the branch. When you write something to fileA,
++aufs copies-up it to the upper writable branch. Additionally aufs
++creates a hardlink under the Pseudo-link Directory of the writable
++branch. The inode of a pseudo-link is kept in aufs super_block as a
++simple list. If fileB is read after unlinking fileA, aufs returns
++filedata from the pseudo-link instead of the lower readonly
++branch. Because the pseudo-link is based upon the inode, to keep the
++inode number by xino (see above) is important.
++
++All the hardlinks under the Pseudo-link Directory of the writable branch
++should be restored in a proper location later. Aufs provides a utility
++to do this. The userspace helpers executed at remounting and unmounting
++aufs by default.
++
++
++XIB(external inode number bitmap)
++----------------------------------------------------------------------
++Addition to the xino file per a branch, aufs has an external inode number
++bitmap in a superblock object. It is also a file such like a xino file.
++It is a simple bitmap to mark whether the aufs inode number is in-use or
++not.
++To reduce the file I/O, aufs prepares a single memory page to cache xib.
++
++Aufs implements a feature to truncate/refresh both of xino and xib to
++reduce the number of consumed disk blocks for these files.
++
++
++Virtual or Vertical Dir
++----------------------------------------------------------------------
++In order to support multiple layers (branches), aufs readdir operation
++constructs a virtual dir block on memory. For readdir, aufs calls
++vfs_readdir() internally for each dir on branches, merges their entries
++with eliminating the whiteout-ed ones, and sets it to file (dir)
++object. So the file object has its entry list until it is closed. The
++entry list will be updated when the file position is zero and becomes
++old. This decision is made in aufs automatically.
++
++The dynamically allocated memory block for the name of entries has a
++unit of 512 bytes (by default) and stores the names contiguously (no
++padding). Another block for each entry is handled by kmem_cache too.
++During building dir blocks, aufs creates hash list and judging whether
++the entry is whiteouted by its upper branch or already listed.
++
++Some people may call it can be a security hole or invite DoS attack
++since the opened and once readdir-ed dir (file object) holds its entry
++list and becomes a pressure for system memory. But I'd say it is similar
++to files under /proc or /sys. The virtual files in them also holds a
++memory page (generally) while they are opened. When an idea to reduce
++memory for them is introduced, it will be applied to aufs too.
++
++
++Workqueue
++----------------------------------------------------------------------
++Aufs sometimes requires privilege access to a branch. For instance,
++in copy-up/down operation. When a user process is going to make changes
++to a file which exists in the lower readonly branch only, and the mode
++of one of ancestor directories may not be writable by a user
++process. Here aufs copy-up the file with its ancestors and they may
++require privilege to set its owner/group/mode/etc.
++This is a typical case of a application character of aufs (see
++Introduction).
++
++Aufs uses workqueue synchronously for this case. It creates its own
++workqueue. The workqueue is a kernel thread and has privilege. Aufs
++passes the request to call mkdir or write (for example), and wait for
++its completion. This approach solves a problem of a signal handler
++simply.
++If aufs didn't adopt the workqueue and changed the privilege of the
++process, and if the mkdir/write call arises SIGXFSZ or other signal,
++then the user process might gain a privilege or the generated core file
++was owned by a superuser. But I have a plan to switch to a new
++credential approach which will be introduced in linux-2.6.29.
++
++Also aufs uses the system global workqueue ("events" kernel thread) too
++for asynchronous tasks, such like handling inotify, re-creating a
++whiteout base and etc. This is unrelated to a privilege.
++Most of aufs operation tries acquiring a rw_semaphore for aufs
++superblock at the beginning, at the same time waits for the completion
++of all queued asynchronous tasks.
++
++
++Whiteout
++----------------------------------------------------------------------
++The whiteout in aufs is very similar to Unionfs's. That is represented
++by its filename. UnionMount takes an approach of a file mode, but I am
++afraid several utilities (find(1) or something) will have to support it.
++
++Basically the whiteout represents "logical deletion" which stops aufs to
++lookup further, but also it represents "dir is opaque" which also stop
++lookup.
++
++In aufs, rmdir(2) and rename(2) for dir uses whiteout alternatively.
++In order to make several functions in a single systemcall to be
++revertible, aufs adopts an approach to rename a directory to a temporary
++unique whiteouted name.
++For example, in rename(2) dir where the target dir already existed, aufs
++renames the target dir to a temporary unique whiteouted name before the
++actual rename on a branch and then handles other actions (make it opaque,
++update the attributes, etc). If an error happens in these actions, aufs
++simply renames the whiteouted name back and returns an error. If all are
++succeeded, aufs registers a function to remove the whiteouted unique
++temporary name completely and asynchronously to the system global
++workqueue.
++
++
++Copy-up
++----------------------------------------------------------------------
++It is a well-known feature or concept.
++When user modifies a file on a readonly branch, aufs operate "copy-up"
++internally and makes change to the new file on the upper writable branch.
++When the trigger systemcall does not update the timestamps of the parent
++dir, aufs reverts it after copy-up.
+diff -uNr test/Documentation/filesystems/aufs/design/03lookup.txt aufs2-standalone/Documentation/filesystems/aufs/design/03lookup.txt
+--- test/Documentation/filesystems/aufs/design/03lookup.txt	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/Documentation/filesystems/aufs/design/03lookup.txt	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,95 @@
++
++# Copyright (C) 2005-2009 Junjiro R. Okajima
++# 
++# This program is free software; you can redistribute it and/or modify
++# it under the terms of the GNU General Public License as published by
++# the Free Software Foundation; either version 2 of the License, or
++# (at your option) any later version.
++
++Lookup in a Branch
++----------------------------------------------------------------------
++Since aufs has a character of sub-VFS (see Introduction), it operates
++lookup for branches as VFS does. It may be a heavy work. Generally
++speaking struct nameidata is a bigger structure and includes many
++information. But almost all lookup operation in aufs is the simplest
++case, ie. lookup only an entry directly connected to its parent. Digging
++down the directory hierarchy is unnecessary.
++
++VFS has a function lookup_one_len() for that use, but it is not usable
++for a branch filesystem which requires struct nameidata. So aufs
++implements a simple lookup wrapper function. When a branch filesystem
++allows NULL as nameidata, it calls lookup_one_len(). Otherwise it builds
++a simplest nameidata and calls lookup_hash().
++Here aufs applies "a principle in NFSD", ie. if the filesystem supports
++NFS-export, then it has to support NULL as a nameidata parameter for
++->create(), ->lookup() and ->d_revalidate(). So the lookup wrapper in
++aufs tests if ->s_export_op in the branch is NULL or not.
++
++When a branch is a remote filesystem, aufs trusts its ->d_revalidate().
++For d_revalidate, aufs implements three levels of revalidate tests. See
++"Revalidate Dentry and UDBA" in detail.
++
++
++Loopback Mount
++----------------------------------------------------------------------
++Basically aufs supports any type of filesystem and block device for a
++branch (actually there are some exceptions). But it is prohibited to add
++a loopback mounted one whose backend file exists in a filesystem which is
++already added to aufs. The reason is to protect aufs from a recursive
++lookup. If it was allowed, the aufs lookup operation might re-enter a
++lookup for the loopback mounted branch in the same context, and will
++cause a deadlock.
++
++
++Revalidate Dentry and UDBA (User's Direct Branch Access)
++----------------------------------------------------------------------
++Generally VFS helpers re-validate a dentry as a part of lookup.
++0. digging down the directory hierarchy.
++1. lock the parent dir by its i_mutex.
++2. lookup the final (child) entry.
++3. revalidate it.
++4. call the actual operation (create, unlink, etc.)
++5. unlock the parent dir
++
++If the filesystem implements its ->d_revalidate() (step 3), then it is
++called. Actually aufs implements it and checks the dentry on a branch is
++still valid.
++But it is not enough. Because aufs has to release the lock for the
++parent dir on a branch at the end of ->lookup() (step 2) and
++->d_revalidate() (step 3) while the i_mutex of the aufs dir is still
++held by VFS.
++If the file on a branch is changed directly, eg. bypassing aufs, after
++aufs released the lock, then the subsequent operation may cause
++something unpleasant result.
++
++This situation is a result of VFS architecture, ->lookup() and
++->d_revalidate() is separated. But I never say it is wrong. It is a good
++design from VFS's point of view. It is just not suitable for sub-VFS
++character in aufs.
++
++Aufs supports such case by three level of revalidation which is
++selectable by user.
++1. Simple Revalidate
++   Addition to the native flow in VFS's, confirm the child-parent
++   relationship on the branch just after locking the parent dir on the
++   branch in the "actual operation" (step 4). When this validation
++   fails, aufs returns EBUSY. ->d_revalidate() (step 3) in aufs still
++   checks the validation of the dentry on branches.
++2. Monitor Changes Internally by Inotify
++   Addition to above, in the "actual operation" (step 4) aufs re-lookup
++   the dentry on the branch, and returns EBUSY if it finds different
++   dentry.
++   Additionally, aufs sets the inotify watch for every dir on branches
++   during it is in cache. When the event is notified, aufs registers a
++   function to kernel 'events' thread by schedule_work(). And the
++   function sets some special status to the cached aufs dentry and inode
++   private data. If they are not cached, then aufs has nothing to
++   do. When the same file is accessed through aufs (step 0-3) later,
++   aufs will detect the status and refresh all necessary data.
++   In this mode, aufs has to ignore the event which is fired by aufs
++   itself.
++3. No Extra Validation
++   This is the simplest test and doesn't add any additional revalidation
++   test, and skip therevalidatin in step 4. It is useful and improves
++   aufs performance when system surely hide the aufs branches from user,
++   by over-mounting something (or another method).
+diff -uNr test/Documentation/filesystems/aufs/design/04branch.txt aufs2-standalone/Documentation/filesystems/aufs/design/04branch.txt
+--- test/Documentation/filesystems/aufs/design/04branch.txt	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/Documentation/filesystems/aufs/design/04branch.txt	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,67 @@
++
++# Copyright (C) 2005-2009 Junjiro R. Okajima
++# 
++# This program is free software; you can redistribute it and/or modify
++# it under the terms of the GNU General Public License as published by
++# the Free Software Foundation; either version 2 of the License, or
++# (at your option) any later version.
++
++Branch Manipulation
++
++Since aufs supports dynamic branch manipulation, ie. add/remove a branch
++and changing its permission/attribute, there are a lot of works to do.
++
++
++Add a Branch
++----------------------------------------------------------------------
++o Confirm the adding dir exists outside of aufs, including loopback
++  mount.
++- and other various attributes...
++o Initialize the xino file and whiteout bases if necessary.
++  See struct.txt.
++
++o Check the owner/group/mode of the directory
++  When the owner/group/mode of the adding directory differs from the
++  existing branch, aufs issues a warning because it may impose a
++  security risk.
++  For example, when a upper writable branch has a world writable empty
++  top directory, a malicious user can create any files on the writable
++  branch directly, like copy-up and modify manually. If something like
++  /etc/{passwd,shadow} exists on the lower readonly branch but the upper
++  writable branch, and the writable branch is world-writable, then a
++  malicious guy may create /etc/passwd on the writable branch directly
++  and the infected file will be valid in aufs.
++  I am afraid it can be a security issue, but nothing to do except
++  producing a warning.
++
++
++Delete a Branch
++----------------------------------------------------------------------
++o Confirm the deleting branch is not busy
++  To be general, there is one merit to adopt "remount" interface to
++  manipulate branches. It is to discard caches. At deleting a branch,
++  aufs checks the still cached (and connected) dentries and inodes. If
++  there are any, then they are all in-use. An inode without its
++  corresponding dentry can be alive alone (for example, inotify case).
++
++  For the cached one, aufs checks whether the same named entry exists on
++  other branches.
++  If the cached one is a directory, because aufs provides a merged view
++  to users, as long as one dir is left on any branch aufs can show the
++  dir to users. In this case, the branch can be removed from aufs.
++  Otherwise aufs rejects deleting the branch.
++
++  If any file on the deleting branch is opened by aufs, then aufs
++  rejects deleting.
++
++
++Modify the Permission of a Branch
++----------------------------------------------------------------------
++o Re-initialize or remove the xino file and whiteout bases if necessary.
++  See struct.txt.
++
++o rw --> ro: Confirm the modifying branch is not busy
++  Aufs rejects the request if any of these conditions are true.
++  - a file on the branch is mmap-ed.
++  - a regular file on the branch is opened for write and there is no
++    same named entry on the upper branch.
+diff -uNr test/Documentation/filesystems/aufs/design/05wbr_policy.txt aufs2-standalone/Documentation/filesystems/aufs/design/05wbr_policy.txt
+--- test/Documentation/filesystems/aufs/design/05wbr_policy.txt	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/Documentation/filesystems/aufs/design/05wbr_policy.txt	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,57 @@
++
++# Copyright (C) 2005-2009 Junjiro R. Okajima
++# 
++# This program is free software; you can redistribute it and/or modify
++# it under the terms of the GNU General Public License as published by
++# the Free Software Foundation; either version 2 of the License, or
++# (at your option) any later version.
++
++
++Policies to Select One among Multiple Writable Branches
++----------------------------------------------------------------------
++When the number of writable branch is more than one, aufs has to decide
++the target branch for file creation or copy-up. By default, the highest
++writable branch which has the parent (or ancestor) dir of the target
++file is chosen (top-down-parent policy).
++By user's request, aufs implements some other policies to select the
++writable branch, for file creation two policies, round-robin and
++most-free-space policies. For copy-up three policies, top-down-parent,
++bottom-up-parent and bottom-up policies.
++
++As expected, the round-robin policy selects the branch in circular. When
++you have two writable branches and creates 10 new files, 5 files will be
++created for each branch. mkdir(2) systemcall is an exception. When you
++create 10 new directories, all will be created on the same branch.
++And the most-free-space policy selects the one which has most free
++space among the writable branches. The amount of free space will be
++checked by aufs internally, and users can specify its time interval.
++
++The policies for copy-up is more simple,
++top-down-parent is equivalent to the same named on in create policy,
++bottom-up-parent selects the writable branch where the parent dir
++exists and the nearest upper one from the copyup-source,
++bottom-up selects the nearest upper writable branch from the
++copyup-source, regardless the existence of the parent dir.
++
++There are some rules or exceptions to apply these policies.
++- If there is a readonly branch above the policy-selected branch and
++  the parent dir is marked as opaque (a variation of whiteout), or the
++  target (creating) file is whiteout-ed on the upper readonly branch,
++  then the result of the policy is ignored and the target file will be
++  created on the nearest upper writable branch than the readonly branch.
++- If there is a writable branch above the policy-selected branch and
++  the parent dir is marked as opaque or the target file is whiteouted
++  on the branch, then the result of the policy is ignored and the target
++  file will be created on the highest one among the upper writable
++  branches who has diropq or whiteout. In case of whiteout, aufs removes
++  it as usual.
++- link(2) and rename(2) systemcalls are exceptions in every policy.
++  They try selecting the branch where the source exists as possible
++  since copyup a large file will take long time. If it can't be,
++  ie. the branch where the source exists is readonly, then they will
++  follow the copyup policy.
++- There is an exception for rename(2) when the target exists.
++  If the rename target exists, aufs compares the index of the branches
++  where the source and the target exists and selects the higher
++  one. If the selected branch is readonly, then aufs follows the
++  copyup policy.
+diff -uNr test/Documentation/filesystems/aufs/design/06fmode_exec.txt aufs2-standalone/Documentation/filesystems/aufs/design/06fmode_exec.txt
+--- test/Documentation/filesystems/aufs/design/06fmode_exec.txt	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/Documentation/filesystems/aufs/design/06fmode_exec.txt	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,24 @@
++
++# Copyright (C) 2005-2009 Junjiro R. Okajima
++# 
++# This program is free software; you can redistribute it and/or modify
++# it under the terms of the GNU General Public License as published by
++# the Free Software Foundation; either version 2 of the License, or
++# (at your option) any later version.
++
++FMODE_EXEC and deny_write()
++----------------------------------------------------------------------
++Generally Unix prevents an executing file from writing its filedata.
++In linux it is implemented by deny_write() and allow_write().
++When a file is executed by exec() family, open_exec() (and sys_uselib())
++they opens the file and calls deny_write(). If the file is aufs's virtual
++one, it has no meaning. The file which deny_write() is really necessary
++is the file on a branch. But the FMODE_EXEC flag is not passed to
++->open() operation. So aufs adopt a dirty trick.
++
++- in order to get FMODE_EXEC, aufs ->lookup() and ->d_revalidate() set
++  nd->intent.open.file->private_data to nd->intent.open.flags temporary.
++- in aufs ->open(), when FMODE_EXEC is set in file->private_data, it
++  calls deny_write() for the file on a branch.
++- when the aufs file is released, allow_write() for the file on a branch
++  is called.
+diff -uNr test/Documentation/filesystems/aufs/design/07mmap.txt aufs2-standalone/Documentation/filesystems/aufs/design/07mmap.txt
+--- test/Documentation/filesystems/aufs/design/07mmap.txt	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/Documentation/filesystems/aufs/design/07mmap.txt	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,44 @@
++
++# Copyright (C) 2005-2009 Junjiro R. Okajima
++# 
++# This program is free software; you can redistribute it and/or modify
++# it under the terms of the GNU General Public License as published by
++# the Free Software Foundation; either version 2 of the License, or
++# (at your option) any later version.
++
++mmap(2) -- File Memory Mapping
++----------------------------------------------------------------------
++In aufs, the file-mapped pages are shared between the file on a branch
++and the virtual one in aufs by overriding vm_operation, particularly
++->fault().
++
++In aufs_mmap(),
++- get and store vm_ops of the real file on a branch.
++- map the file of aufs by generic_file_mmap() and set aufs's vm
++  operations.
++
++In aufs_fault(),
++- get the file of aufs from the passed vma, sleep if needed.
++- get the real file on a branch from the aufs file.
++- a race may happen. for instance a multithreaded library. so some lock
++  is implemented.
++- call ->fault() in the previously stored vm_ops with setting the
++  real file on a branch to vm_file.
++- restore vm_file and wake_up if someone else got sleep.
++
++When a branch is added to or deleted from aufs, the same-named file may
++unveil and its contents will be replaced by the new one when a process
++read(2) through previously opened file.
++(Some users may not want to refresh the filedata. For such users, I
++have a plan to implement a mount option 'refrof' which decides to
++refresh the opened files or not. See plan.txt too.)
++In this case, an already mapped file will not be updated since the
++contents are a part of a process already and it should not be changed by
++aufs branch manipulation. (Even if MAP_SHARED is specified, currently).
++Of course, in case of the deleting branch has a busy file, it cannot be
++deleted from the union.
++
++In Unionfs, it took an approach which the memory pages mapped to
++filedata are copied from the lower (real) file into the Unionfs's
++virtual one and handles it by address_space operations. Recently Unionfs
++changed it to this approach which aufs adopted since Jul 2006.
+diff -uNr test/Documentation/filesystems/aufs/design/08plan.txt aufs2-standalone/Documentation/filesystems/aufs/design/08plan.txt
+--- test/Documentation/filesystems/aufs/design/08plan.txt	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/Documentation/filesystems/aufs/design/08plan.txt	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,169 @@
++
++# Copyright (C) 2005-2009 Junjiro R. Okajima
++# 
++# This program is free software; you can redistribute it and/or modify
++# it under the terms of the GNU General Public License as published by
++# the Free Software Foundation; either version 2 of the License, or
++# (at your option) any later version.
++
++Plan
++
++Restoring some features which was implemented in aufs1.
++They were dropped in aufs2 in order to make source files simpler and
++easier to be reviewed.
++
++
++Export Aufs via NFS
++----------------------------------------------------------------------
++Here is an approach I adopt in aufs1.
++- like xino/xib, add a new file 'xigen' which stores aufs inode
++  generation.
++- iget_locked(): initialize aufs inode generation for a new inode, and
++  store it in xigen file.
++- destroy_inode(): increment aufs inode generation and store it in xigen
++  file. it is necessary even if it is not unlinked, because any data of
++  inode may be changed by UDBA.
++- encode_fh(): for a root dir, simply return FILEID_ROOT. otherwise
++  build file handle by
++  + branch id (4 bytes)
++  + superblock generation (4 bytes)
++  + inode number (4 or 8 bytes)
++  + parent dir inode number (4 or 8 bytes)
++  + inode generation (4 bytes))
++  + return value of exportfs_encode_fh() for the parent on a branch (4
++    bytes)
++  + file handle for a branch (by exportfs_encode_fh())
++- fh_to_dentry():
++  + find the index of a branch from its id in handle, and check it is
++    still exist in aufs.
++  + 1st level: get the inode number from handle and search it in cache.
++  + 2nd level: if not found, get the parent inode number from handle and
++    search it in cache. and then open the parent dir, find the matching
++    inode number by vfs_readdir() and get its name, and call
++    lookup_one_len() for the target dentry.
++  + 3rd level: if the parent dir is not cached, call
++    exportfs_decode_fh() for a branch and get the parent on a branch,
++    build a pathname of it, convert it a pathname in aufs, call
++    path_lookup(). now aufs gets a parent dir dentry, then handle it as
++    the 2nd level.
++  + to open the dir, aufs needs struct vfsmount. aufs keeps vfsmount
++    for every branch, but not itself. to get this, (currently) aufs
++    searches in current->nsproxy->mnt_ns list. it may not be a good
++    idea, but I didn't get other approach.
++  + test the generation of the gotten inode.
++- every inode operation: they may get EBUSY due to UDBA. in this case,
++  convert it into ESTALE for NFSD.
++- readdir(): call lockdep_on/off() because filldir in NFSD calls
++  lookup_one_len(), vfs_getattr(), encode_fh() and others.
++
++
++Test Only the Highest One for the Directory Permission (dirperm1 option)
++----------------------------------------------------------------------
++Let's try case study.
++- aufs has two branches, upper readwrite and lower readonly.
++  /au = /rw + /ro
++- "dirA" exists under /ro, but /rw. and its mode is 0700.
++- user invoked "chmod a+rx /au/dirA"
++- then "dirA" becomes world readable?
++
++In this case, /ro/dirA is still 0700 since it exists in readonly branch,
++or it may be a natively readonly filesystem. If aufs respects the lower
++branch, it should not respond readdir request from other users. But user
++allowed it by chmod. Should really aufs rejects showing the entries
++under /ro/dirA?
++
++To be honest, I don't have a best solution for this case. So I
++implemented 'dirperm1' and 'nodirperm1' option in aufs1, and leave it to
++users.
++When dirperm1 is specified, aufs checks only the highest one for the
++directory permission, and shows the entries. Otherwise, as usual, checks
++every dir existing on all branches and rejects the request.
++
++As a side effect, dirperm1 option improves the performance of aufs
++because the number of permission check is reduced.
++
++
++Show Whiteout Mode (shwh)
++----------------------------------------------------------------------
++Generally aufs hides the name of whiteouts. But in some cases, to show
++them is very useful for users. For instance, creating a new middle layer
++(branch) by merging existing layers.
++
++(borrowing aufs1 HOW-TO from a user, Michael Towers)
++When you have three branches,
++- Bottom: 'system', squashfs (underlying base system), read-only
++- Middle: 'mods', squashfs, read-only
++- Top: 'overlay', ram (tmpfs), read-write
++
++The top layer is loaded at boot time and saved at shutdown, to preserve
++the changes made to the system during the session.
++When larger changes have been made, or smaller changes have accumulated,
++the size of the saved top layer data grows. At this point, it would be
++nice to be able to merge the two overlay branches ('mods' and 'overlay')
++and rewrite the 'mods' squashfs, clearing the top layer and thus
++restoring save and load speed.
++
++This merging is simplified by the use of another aufs mount, of just the
++two overlay branches using the 'shwh' option.
++# mount -t aufs -o ro,shwh,br:/livesys/overlay=ro+wh:/livesys/mods=rr+wh \
++	aufs /livesys/merge_union
++
++A merged view of these two branches is then available at
++/livesys/merge_union, and the new feature is that the whiteouts are
++visible!
++Note that in 'shwh' mode the aufs mount must be 'ro', which will disable
++writing to all branches. Also the default mode for all branches is 'ro'.
++It is now possible to save the combined contents of the two overlay
++branches to a new squashfs, e.g.:
++# mksquashfs /livesys/merge_union /path/to/newmods.squash
++
++This new squashfs archive can be stored on the boot device and the
++initramfs will use it to replace the old one at the next boot.
++
++
++Being Another Aufs's Readonly Branch (robr)
++----------------------------------------------------------------------
++Aufs1 allows aufs to be another aufs's readonly branch.
++This feature was developed by a user's request. But it may not be used
++currecnly.
++
++
++Copy-up on Open (coo=)
++----------------------------------------------------------------------
++By default the internal copy-up is executed when it is really necessary.
++It is not done when a file is opened for writing, but when write(2) is
++done. Users who have many (over 100) branches want to know and analyse
++when and what file is copied-up. To insert a new upper branch which
++contains such files only may improve the performance of aufs.
++
++Aufs1 implemented "coo=none | leaf | all" option.
++
++
++Refresh the Opened File (refrof)
++----------------------------------------------------------------------
++This option is implemented in aufs1 but incomplete.
++
++When user reads from a file, he expects to get its latest filedata
++generally. If the file is removed and a new same named file is created,
++the content he gets is unchanged, ie. the unlinked filedata.
++
++Let's try case study again.
++- aufs has two branches.
++  /au = /rw + /ro
++- "fileA" exists under /ro, but /rw.
++- user opened "/au/fileA".
++- he or someone else inserts a branch (/new) between /rw and /ro.
++  /au = /rw + /new + /ro
++- the new branch has "fileA".
++- user reads from the opened "fileA"
++- which filedata should aufs return, from /ro or /new?
++
++Some people says it has to be "from /ro" and it is a semantics of Unix.
++The others say it should be "from /new" because the file is not removed
++and it is equivalent to the case of someone else modifies the file.
++
++Here again I don't have a best and final answer. I got an idea to
++implement 'refrof' and 'norefrof' option. When 'refrof' (REFResh the
++Opened File) is specified (by default), aufs returns the filedata from
++/new.
++Otherwise from /new.
+diff -uNr test/fs/aufs/Kconfig aufs2-standalone/fs/aufs/Kconfig
+--- test/fs/aufs/Kconfig	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/Kconfig	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,78 @@
++config AUFS_FS
++	tristate "Aufs (Advanced multi layered unification filesystem) support"
++	depends on EXPERIMENTAL
++	help
++	Aufs is a stackable unification filesystem such as Unionfs,
++	which unifies several directories and provides a merged single
++	directory.
++	In the early days, aufs was entirely re-designed and
++	re-implemented Unionfs Version 1.x series. Introducing many
++	original ideas, approaches and improvements, it becomes totally
++	different from Unionfs while keeping the basic features.
++
++if AUFS_FS
++choice
++	prompt "Maximum number of branches"
++	default AUFS_BRANCH_MAX_127
++	help
++	Specifies the maximum number of branches (or member directories)
++	in a single aufs. The larger value consumes more system
++	resources and has a minor impact to performance.
++config AUFS_BRANCH_MAX_127
++	bool "127"
++	help
++	Specifies the maximum number of branches (or member directories)
++	in a single aufs. The larger value consumes more system
++	resources and has a minor impact to performance.
++config AUFS_BRANCH_MAX_511
++	bool "511"
++	help
++	Specifies the maximum number of branches (or member directories)
++	in a single aufs. The larger value consumes more system
++	resources and has a minor impact to performance.
++config AUFS_BRANCH_MAX_1023
++	bool "1023"
++	help
++	Specifies the maximum number of branches (or member directories)
++	in a single aufs. The larger value consumes more system
++	resources and has a minor impact to performance.
++config AUFS_BRANCH_MAX_32767
++	bool "32767"
++	help
++	Specifies the maximum number of branches (or member directories)
++	in a single aufs. The larger value consumes more system
++	resources and has a minor impact to performance.
++endchoice
++
++config AUFS_HINOTIFY
++	bool "Use inotify to detect actions on a branch"
++	depends on INOTIFY
++	help
++	If you want to modify files on branches directly, eg. bypassing aufs,
++	and want aufs to detect the changes of them fully, then enable this
++	option and use 'udba=inotify' mount option.
++	It will have a negative impact to the performance.
++	See detail in aufs.5.
++
++config AUFS_DEBUG
++	bool "Debug aufs"
++	help
++	Enable this to compile aufs internal debug code.
++	It will have a negative impact to the performance.
++
++config AUFS_MAGIC_SYSRQ
++	bool
++	depends on AUFS_DEBUG && MAGIC_SYSRQ
++	default y
++	help
++	Automatic configuration for internal use.
++	When aufs supports Magic SysRq, enabled automatically.
++
++config AUFS_BDEV_LOOP
++	bool
++	depends on BLK_DEV_LOOP
++	default y
++	help
++	Automatic configuration for internal use.
++	Convert =[ym] into =y.
++endif
+diff -uNr test/fs/aufs/Makefile aufs2-standalone/fs/aufs/Makefile
+--- test/fs/aufs/Makefile	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/Makefile	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,20 @@
++
++include ${src}/magic.mk
++-include ${src}/priv_def.mk
++
++obj-$(CONFIG_AUFS_FS) += aufs.o
++aufs-y := module.o sbinfo.o super.o branch.o xino.o sysaufs.o opts.o \
++	wkq.o vfsub.o dcsub.o \
++	cpup.o whout.o plink.o wbr_policy.o \
++	dinfo.o dentry.o \
++	finfo.o file.o f_op.o \
++	dir.o vdir.o \
++	iinfo.o inode.o i_op.o i_op_add.o i_op_del.o i_op_ren.o \
++	ioctl.o
++
++# all are boolean
++aufs-$(CONFIG_SYSFS) += sysfs.o
++aufs-$(CONFIG_AUFS_BDEV_LOOP) += loop.o
++aufs-$(CONFIG_AUFS_HINOTIFY) += hinotify.o
++aufs-$(CONFIG_AUFS_DEBUG) += debug.o
++aufs-$(CONFIG_AUFS_MAGIC_SYSRQ) += sysrq.o
+diff -uNr test/fs/aufs/aufs.h aufs2-standalone/fs/aufs/aufs.h
+--- test/fs/aufs/aufs.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/aufs.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,43 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * all header files
++ */
++
++#ifndef __AUFS_H__
++#define __AUFS_H__
++
++#ifdef __KERNEL__
++
++#include <linux/bug.h>
++
++#include "debug.h"
++
++#include "branch.h"
++#include "cpup.h"
++#include "dcsub.h"
++#include "dentry.h"
++#include "dir.h"
++#include "file.h"
++#include "fstype.h"
++#include "inode.h"
++#include "loop.h"
++#include "module.h"
++#include "opts.h"
++#include "rwsem.h"
++#include "spl.h"
++#include "super.h"
++#include "sysaufs.h"
++#include "vfsub.h"
++#include "whout.h"
++#include "wkq.h"
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_H__ */
+diff -uNr test/fs/aufs/branch.c aufs2-standalone/fs/aufs/branch.c
+--- test/fs/aufs/branch.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/branch.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,944 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * branch management
++ */
++
++#include "aufs.h"
++
++/*
++ * free a single branch
++ */
++static void au_br_do_free(struct au_branch *br)
++{
++	int i;
++	struct au_wbr *wbr;
++
++	if (br->br_xino.xi_file)
++		fput(br->br_xino.xi_file);
++	mutex_destroy(&br->br_xino.xi_nondir_mtx);
++
++	AuDebugOn(atomic_read(&br->br_count));
++
++	wbr = br->br_wbr;
++	if (wbr) {
++		for (i = 0; i < AuBrWh_Last; i++)
++			dput(wbr->wbr_wh[i]);
++		AuDebugOn(atomic_read(&wbr->wbr_wh_running));
++		au_rwsem_destroy(&wbr->wbr_wh_rwsem);
++	}
++
++	/* some filesystems acquire extra lock */
++	lockdep_off();
++	mntput(br->br_mnt);
++	lockdep_on();
++
++	kfree(wbr);
++	kfree(br);
++}
++
++/*
++ * frees all branches
++ */
++void au_br_free(struct au_sbinfo *sbinfo)
++{
++	aufs_bindex_t bmax;
++	struct au_branch **br;
++
++	bmax = sbinfo->si_bend + 1;
++	br = sbinfo->si_branch;
++	while (bmax--)
++		au_br_do_free(*br++);
++}
++
++/*
++ * find the index of a branch which is specified by @br_id.
++ */
++int au_br_index(struct super_block *sb, aufs_bindex_t br_id)
++{
++	aufs_bindex_t bindex, bend;
++
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++)
++		if (au_sbr_id(sb, bindex) == br_id)
++			return bindex;
++	return -1;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * add a branch
++ */
++
++static int test_overlap(struct super_block *sb, struct dentry *h_d1,
++			struct dentry *h_d2)
++{
++	if (unlikely(h_d1 == h_d2))
++		return 1;
++	return !!au_test_subdir(h_d1, h_d2)
++		|| !!au_test_subdir(h_d2, h_d1)
++		|| au_test_loopback_overlap(sb, h_d1, h_d2)
++		|| au_test_loopback_overlap(sb, h_d2, h_d1);
++}
++
++/*
++ * returns a newly allocated branch. @new_nbranch is a number of branches
++ * after adding a branch.
++ */
++static struct au_branch *au_br_alloc(struct super_block *sb, int new_nbranch,
++				     int perm)
++{
++	struct au_branch *add_branch;
++	struct dentry *root;
++
++	root = sb->s_root;
++	add_branch = kmalloc(sizeof(*add_branch), GFP_NOFS);
++	if (unlikely(!add_branch))
++		goto out;
++
++	add_branch->br_wbr = NULL;
++	if (au_br_writable(perm)) {
++		/* may be freed separately at changing the branch permission */
++		add_branch->br_wbr = kmalloc(sizeof(*add_branch->br_wbr),
++					     GFP_NOFS);
++		if (unlikely(!add_branch->br_wbr))
++			goto out_br;
++	}
++
++	if (unlikely(au_sbr_realloc(au_sbi(sb), new_nbranch)
++		     || au_di_realloc(au_di(root), new_nbranch)
++		     || au_ii_realloc(au_ii(root->d_inode), new_nbranch)))
++		goto out_wbr;
++	return add_branch; /* success */
++
++ out_wbr:
++	kfree(add_branch->br_wbr);
++ out_br:
++	kfree(add_branch);
++ out:
++	return ERR_PTR(-ENOMEM);
++}
++
++/*
++ * test if the branch permission is legal or not.
++ */
++static int test_br(struct inode *inode, int brperm, char *path)
++{
++	int err;
++
++	err = 0;
++	if (unlikely(au_br_writable(brperm) && IS_RDONLY(inode))) {
++		AuErr("write permission for readonly mount or inode, %s\n",
++		      path);
++		err = -EINVAL;
++	}
++
++	return err;
++}
++
++/*
++ * returns:
++ * 0: success, the caller will add it
++ * plus: success, it is already unified, the caller should ignore it
++ * minus: error
++ */
++static int test_add(struct super_block *sb, struct au_opt_add *add, int remount)
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct dentry *root;
++	struct inode *inode, *h_inode;
++
++	root = sb->s_root;
++	bend = au_sbend(sb);
++	if (unlikely(bend >= 0
++		     && au_find_dbindex(root, add->path.dentry) >= 0)) {
++		err = 1;
++		if (!remount) {
++			err = -EINVAL;
++			AuErr("%s duplicated\n", add->pathname);
++		}
++		goto out;
++	}
++
++	err = -ENOSPC; /* -E2BIG; */
++	if (unlikely(AUFS_BRANCH_MAX <= add->bindex
++		     || AUFS_BRANCH_MAX - 1 <= bend)) {
++		AuErr("number of branches exceeded %s\n", add->pathname);
++		goto out;
++	}
++
++	err = -EDOM;
++	if (unlikely(add->bindex < 0 || bend + 1 < add->bindex)) {
++		AuErr("bad index %d\n", add->bindex);
++		goto out;
++	}
++
++	inode = add->path.dentry->d_inode;
++	err = -ENOENT;
++	if (unlikely(!inode->i_nlink)) {
++		AuErr("no existence %s\n", add->pathname);
++		goto out;
++	}
++
++	err = -EINVAL;
++	if (unlikely(inode->i_sb == sb)) {
++		AuErr("%s must be outside\n", add->pathname);
++		goto out;
++	}
++
++	if (unlikely(au_test_fs_unsuppoted(inode->i_sb))) {
++		AuErr("unsupported filesystem, %s (%s)\n",
++		      add->pathname, au_sbtype(inode->i_sb));
++		goto out;
++	}
++
++	err = test_br(add->path.dentry->d_inode, add->perm, add->pathname);
++	if (unlikely(err))
++		goto out;
++
++	if (bend < 0)
++		return 0; /* success */
++
++	err = -EINVAL;
++	for (bindex = 0; bindex <= bend; bindex++)
++		if (unlikely(test_overlap(sb, add->path.dentry,
++					  au_h_dptr(root, bindex)))) {
++			AuErr("%s is overlapped\n", add->pathname);
++			goto out;
++		}
++
++	err = 0;
++	if (au_opt_test(au_mntflags(sb), WARN_PERM)) {
++		h_inode = au_h_dptr(root, 0)->d_inode;
++		if ((h_inode->i_mode & S_IALLUGO) != (inode->i_mode & S_IALLUGO)
++		    || h_inode->i_uid != inode->i_uid
++		    || h_inode->i_gid != inode->i_gid)
++			AuWarn("uid/gid/perm %s %u/%u/0%o, %u/%u/0%o\n",
++			       add->pathname,
++			       inode->i_uid, inode->i_gid,
++			       (inode->i_mode & S_IALLUGO),
++			       h_inode->i_uid, h_inode->i_gid,
++			       (h_inode->i_mode & S_IALLUGO));
++	}
++
++ out:
++	return err;
++}
++
++/*
++ * initialize or clean the whiteouts for an adding branch
++ */
++static int au_br_init_wh(struct super_block *sb, struct au_branch *br,
++			 int new_perm, struct dentry *h_root)
++{
++	int err, old_perm;
++	aufs_bindex_t bindex;
++	struct mutex *h_mtx;
++	struct au_wbr *wbr;
++	struct au_hinode *hdir;
++
++	wbr = br->br_wbr;
++	old_perm = br->br_perm;
++	br->br_perm = new_perm;
++	hdir = NULL;
++	h_mtx = NULL;
++	bindex = au_br_index(sb, br->br_id);
++	if (0 <= bindex) {
++		hdir = au_hi(sb->s_root->d_inode, bindex);
++		au_hin_imtx_lock_nested(hdir, AuLsc_I_PARENT);
++	} else {
++		h_mtx = &h_root->d_inode->i_mutex;
++		mutex_lock_nested(h_mtx, AuLsc_I_PARENT);
++	}
++	if (!wbr)
++		err = au_wh_init(h_root, br, sb);
++	else {
++		wbr_wh_write_lock(wbr);
++		err = au_wh_init(h_root, br, sb);
++		wbr_wh_write_unlock(wbr);
++	}
++	if (hdir)
++		au_hin_imtx_unlock(hdir);
++	else
++		mutex_unlock(h_mtx);
++	br->br_perm = old_perm;
++
++	if (!err && wbr && !au_br_writable(new_perm)) {
++		kfree(wbr);
++		br->br_wbr = NULL;
++	}
++
++	return err;
++}
++
++static int au_wbr_init(struct au_branch *br, struct super_block *sb,
++		       int perm, struct path *path)
++{
++	int err;
++	struct au_wbr *wbr;
++
++	wbr = br->br_wbr;
++	init_rwsem(&wbr->wbr_wh_rwsem);
++	memset(wbr->wbr_wh, 0, sizeof(wbr->wbr_wh));
++	atomic_set(&wbr->wbr_wh_running, 0);
++	wbr->wbr_bytes = 0;
++
++	err = au_br_init_wh(sb, br, perm, path->dentry);
++
++	return err;
++}
++
++/* intialize a new branch */
++static int au_br_init(struct au_branch *br, struct super_block *sb,
++		      struct au_opt_add *add)
++{
++	int err;
++
++	err = 0;
++	br->br_xino.xi_file = NULL;
++	mutex_init(&br->br_xino.xi_nondir_mtx);
++	br->br_perm = add->perm;
++	br->br_mnt = add->path.mnt; /* set first, mntget() later */
++	atomic_set(&br->br_count, 0);
++	br->br_xino_upper = AUFS_XINO_TRUNC_INIT;
++	atomic_set(&br->br_xino_running, 0);
++	br->br_id = au_new_br_id(sb);
++
++	if (au_br_writable(add->perm)) {
++		err = au_wbr_init(br, sb, add->perm, &add->path);
++		if (unlikely(err))
++			goto out;
++	}
++
++	if (au_opt_test(au_mntflags(sb), XINO)) {
++		err = au_xino_br(sb, br, add->path.dentry->d_inode->i_ino,
++				 au_sbr(sb, 0)->br_xino.xi_file, /*do_test*/1);
++		if (unlikely(err)) {
++			AuDebugOn(br->br_xino.xi_file);
++			goto out;
++		}
++	}
++
++	sysaufs_br_init(br);
++	mntget(add->path.mnt);
++
++ out:
++	return err;
++}
++
++static void au_br_do_add_brp(struct au_sbinfo *sbinfo, aufs_bindex_t bindex,
++			     struct au_branch *br, aufs_bindex_t bend,
++			     aufs_bindex_t amount)
++{
++	struct au_branch **brp;
++
++	brp = sbinfo->si_branch + bindex;
++	memmove(brp + 1, brp, sizeof(*brp) * amount);
++	*brp = br;
++	sbinfo->si_bend++;
++	if (unlikely(bend < 0))
++		sbinfo->si_bend = 0;
++}
++
++static void au_br_do_add_hdp(struct au_dinfo *dinfo, aufs_bindex_t bindex,
++			     aufs_bindex_t bend, aufs_bindex_t amount)
++{
++	struct au_hdentry *hdp;
++
++	hdp = dinfo->di_hdentry + bindex;
++	memmove(hdp + 1, hdp, sizeof(*hdp) * amount);
++	au_h_dentry_init(hdp);
++	dinfo->di_bend++;
++	if (unlikely(bend < 0))
++		dinfo->di_bstart = 0;
++}
++
++static void au_br_do_add_hip(struct au_iinfo *iinfo, aufs_bindex_t bindex,
++			     aufs_bindex_t bend, aufs_bindex_t amount)
++{
++	struct au_hinode *hip;
++
++	hip = iinfo->ii_hinode + bindex;
++	memmove(hip + 1, hip, sizeof(*hip) * amount);
++	hip->hi_inode = NULL;
++	au_hin_init(hip, NULL);
++	iinfo->ii_bend++;
++	if (unlikely(bend < 0))
++		iinfo->ii_bstart = 0;
++}
++
++static void au_br_do_add(struct super_block *sb, struct dentry *h_dentry,
++			 struct au_branch *br, aufs_bindex_t bindex)
++{
++	struct dentry *root;
++	struct inode *root_inode;
++	aufs_bindex_t bend, amount;
++
++	root = sb->s_root;
++	root_inode = root->d_inode;
++	au_plink_block_maintain(sb);
++	bend = au_sbend(sb);
++	amount = bend + 1 - bindex;
++	au_br_do_add_brp(au_sbi(sb), bindex, br, bend, amount);
++	au_br_do_add_hdp(au_di(root), bindex, bend, amount);
++	au_br_do_add_hip(au_ii(root_inode), bindex, bend, amount);
++	au_set_h_dptr(root, bindex, dget(h_dentry));
++	au_set_h_iptr(root_inode, bindex, au_igrab(h_dentry->d_inode),
++		      /*flags*/0);
++}
++
++int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount)
++{
++	int err;
++	unsigned long long maxb;
++	aufs_bindex_t bend, add_bindex;
++	struct dentry *root, *h_dentry;
++	struct inode *root_inode;
++	struct au_branch *add_branch;
++
++	root = sb->s_root;
++	root_inode = root->d_inode;
++	IMustLock(root_inode);
++	err = test_add(sb, add, remount);
++	if (unlikely(err < 0))
++		goto out;
++	if (err) {
++		err = 0;
++		goto out; /* success */
++	}
++
++	bend = au_sbend(sb);
++	add_branch = au_br_alloc(sb, bend + 2, add->perm);
++	err = PTR_ERR(add_branch);
++	if (IS_ERR(add_branch))
++		goto out;
++
++	err = au_br_init(add_branch, sb, add);
++	if (unlikely(err)) {
++		au_br_do_free(add_branch);
++		goto out;
++	}
++
++	add_bindex = add->bindex;
++	h_dentry = add->path.dentry;
++	if (!remount)
++		au_br_do_add(sb, h_dentry, add_branch, add_bindex);
++	else {
++		sysaufs_brs_del(sb, add_bindex);
++		au_br_do_add(sb, h_dentry, add_branch, add_bindex);
++		sysaufs_brs_add(sb, add_bindex);
++	}
++
++	if (!add_bindex)
++		au_cpup_attr_all(root_inode, /*force*/1);
++	else
++		au_add_nlink(root_inode, h_dentry->d_inode);
++	maxb = h_dentry->d_sb->s_maxbytes;
++	if (sb->s_maxbytes < maxb)
++		sb->s_maxbytes = maxb;
++
++	/*
++	 * this test/set prevents aufs from handling unnecesary inotify events
++	 * of xino files, in a case of re-adding a writable branch which was
++	 * once detached from aufs.
++	 */
++	if (au_xino_brid(sb) < 0
++	    && au_br_writable(add_branch->br_perm)
++	    && !au_test_fs_bad_xino(h_dentry->d_sb)
++	    && add_branch->br_xino.xi_file
++	    && add_branch->br_xino.xi_file->f_dentry->d_parent == h_dentry)
++		au_xino_brid_set(sb, add_branch->br_id);
++
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * delete a branch
++ */
++
++/* to show the line number, do not make it inlined function */
++#define AuVerbose(do_info, fmt, args...) do { \
++	if (do_info) \
++		AuInfo(fmt, ##args); \
++} while (0)
++
++/*
++ * test if the branch is deletable or not.
++ */
++static int test_dentry_busy(struct dentry *root, aufs_bindex_t bindex,
++			    unsigned int sigen)
++{
++	int err, i, j, ndentry;
++	aufs_bindex_t bstart, bend;
++	unsigned char verbose;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry *d;
++	struct inode *inode;
++
++	err = au_dpages_init(&dpages, GFP_NOFS);
++	if (unlikely(err))
++		goto out;
++	err = au_dcsub_pages(&dpages, root, NULL, NULL);
++	if (unlikely(err))
++		goto out_dpages;
++
++	verbose = !!au_opt_test(au_mntflags(root->d_sb), VERBOSE);
++	for (i = 0; !err && i < dpages.ndpage; i++) {
++		dpage = dpages.dpages + i;
++		ndentry = dpage->ndentry;
++		for (j = 0; !err && j < ndentry; j++) {
++			d = dpage->dentries[j];
++			AuDebugOn(!atomic_read(&d->d_count));
++			inode = d->d_inode;
++			if (au_digen(d) == sigen && au_iigen(inode) == sigen)
++				di_read_lock_child(d, AuLock_IR);
++			else {
++				di_write_lock_child(d);
++				err = au_reval_dpath(d, sigen);
++				if (!err)
++					di_downgrade_lock(d, AuLock_IR);
++				else {
++					di_write_unlock(d);
++					break;
++				}
++			}
++
++			bstart = au_dbstart(d);
++			bend = au_dbend(d);
++			if (bstart <= bindex
++			    && bindex <= bend
++			    && au_h_dptr(d, bindex)
++			    && (!S_ISDIR(inode->i_mode) || bstart == bend)) {
++				err = -EBUSY;
++				AuVerbose(verbose, "busy %.*s\n", AuDLNPair(d));
++			}
++			di_read_unlock(d, AuLock_IR);
++		}
++	}
++
++ out_dpages:
++	au_dpages_free(&dpages);
++ out:
++	return err;
++}
++
++static int test_inode_busy(struct super_block *sb, aufs_bindex_t bindex,
++			   unsigned int sigen)
++{
++	int err;
++	struct inode *i;
++	aufs_bindex_t bstart, bend;
++	unsigned char verbose;
++
++	err = 0;
++	verbose = !!au_opt_test(au_mntflags(sb), VERBOSE);
++	list_for_each_entry(i, &sb->s_inodes, i_sb_list) {
++		AuDebugOn(!atomic_read(&i->i_count));
++		if (!list_empty(&i->i_dentry))
++			continue;
++
++		if (au_iigen(i) == sigen)
++			ii_read_lock_child(i);
++		else {
++			ii_write_lock_child(i);
++			err = au_refresh_hinode_self(i, /*do_attr*/1);
++			if (!err)
++				ii_downgrade_lock(i);
++			else {
++				ii_write_unlock(i);
++				break;
++			}
++		}
++
++		bstart = au_ibstart(i);
++		bend = au_ibend(i);
++		if (bstart <= bindex
++		    && bindex <= bend
++		    && au_h_iptr(i, bindex)
++		    && (!S_ISDIR(i->i_mode) || bstart == bend)) {
++			err = -EBUSY;
++			AuVerbose(verbose, "busy i%lu\n", i->i_ino);
++			ii_read_unlock(i);
++			break;
++		}
++		ii_read_unlock(i);
++	}
++
++	return err;
++}
++
++static int test_children_busy(struct dentry *root, aufs_bindex_t bindex)
++{
++	int err;
++	unsigned int sigen;
++
++	sigen = au_sigen(root->d_sb);
++	DiMustNoWaiters(root);
++	IiMustNoWaiters(root->d_inode);
++	di_write_unlock(root);
++	err = test_dentry_busy(root, bindex, sigen);
++	if (!err)
++		err = test_inode_busy(root->d_sb, bindex, sigen);
++	di_write_lock_child(root); /* aufs_write_lock() calls ..._child() */
++
++	return err;
++}
++
++static void au_br_do_del_brp(struct au_sbinfo *sbinfo,
++			     const aufs_bindex_t bindex,
++			     const aufs_bindex_t bend)
++{
++	struct au_branch **brp, **p;
++
++	brp = sbinfo->si_branch + bindex;
++	if (bindex < bend)
++		memmove(brp, brp + 1, sizeof(*brp) * (bend - bindex));
++	sbinfo->si_branch[0 + bend] = NULL;
++	sbinfo->si_bend--;
++
++	p = krealloc(sbinfo->si_branch, sizeof(*p) * bend, GFP_NOFS);
++	if (p)
++		sbinfo->si_branch = p;
++}
++
++static void au_br_do_del_hdp(struct au_dinfo *dinfo, const aufs_bindex_t bindex,
++			     const aufs_bindex_t bend)
++{
++	struct au_hdentry *hdp, *p;
++
++	hdp = dinfo->di_hdentry + bindex;
++	if (bindex < bend)
++		memmove(hdp, hdp + 1, sizeof(*hdp) * (bend - bindex));
++	dinfo->di_hdentry[0 + bend].hd_dentry = NULL;
++	dinfo->di_bend--;
++
++	p = krealloc(dinfo->di_hdentry, sizeof(*p) * bend, GFP_NOFS);
++	if (p)
++		dinfo->di_hdentry = p;
++}
++
++static void au_br_do_del_hip(struct au_iinfo *iinfo, const aufs_bindex_t bindex,
++			     const aufs_bindex_t bend)
++{
++	struct au_hinode *hip, *p;
++
++	hip = iinfo->ii_hinode + bindex;
++	if (bindex < bend)
++		memmove(hip, hip + 1, sizeof(*hip) * (bend - bindex));
++	iinfo->ii_hinode[0 + bend].hi_inode = NULL;
++	au_hin_init(iinfo->ii_hinode + bend, NULL);
++	iinfo->ii_bend--;
++
++	p = krealloc(iinfo->ii_hinode, sizeof(*p) * bend, GFP_NOFS);
++	if (p)
++		iinfo->ii_hinode = p;
++}
++
++static void au_br_do_del(struct super_block *sb, aufs_bindex_t bindex,
++			 struct au_branch *br)
++{
++	aufs_bindex_t bend;
++	struct au_sbinfo *sbinfo;
++	struct dentry *root;
++	struct inode *inode;
++
++	root = sb->s_root;
++	inode = root->d_inode;
++	au_plink_block_maintain(sb);
++	sbinfo = au_sbi(sb);
++	bend = sbinfo->si_bend;
++
++	dput(au_h_dptr(root, bindex));
++	au_hiput(au_hi(inode, bindex));
++	au_br_do_free(br);
++
++	au_br_do_del_brp(sbinfo, bindex, bend);
++	au_br_do_del_hdp(au_di(root), bindex, bend);
++	au_br_do_del_hip(au_ii(inode), bindex, bend);
++}
++
++int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount)
++{
++	int err, rerr, i;
++	unsigned int mnt_flags;
++	aufs_bindex_t bindex, bend, br_id;
++	unsigned char do_wh, verbose;
++	struct au_branch *br;
++	struct au_wbr *wbr;
++
++	err = 0;
++	bindex = au_find_dbindex(sb->s_root, del->h_path.dentry);
++	if (bindex < 0) {
++		if (remount)
++			goto out; /* success */
++		err = -ENOENT;
++		AuErr("%s no such branch\n", del->pathname);
++		goto out;
++	}
++	AuDbg("bindex b%d\n", bindex);
++
++	err = -EBUSY;
++	mnt_flags = au_mntflags(sb);
++	verbose = !!au_opt_test(mnt_flags, VERBOSE);
++	bend = au_sbend(sb);
++	if (unlikely(!bend)) {
++		AuVerbose(verbose, "no more branches left\n");
++		goto out;
++	}
++	br = au_sbr(sb, bindex);
++	i = atomic_read(&br->br_count);
++	if (unlikely(i)) {
++		AuVerbose(verbose, "%d file(s) opened\n", i);
++		goto out;
++	}
++
++	wbr = br->br_wbr;
++	do_wh = wbr && (wbr->wbr_whbase || wbr->wbr_plink || wbr->wbr_orph);
++	if (do_wh) {
++		for (i = 0; i < AuBrWh_Last; i++) {
++			dput(wbr->wbr_wh[i]);
++			wbr->wbr_wh[i] = NULL;
++		}
++	}
++
++	err = test_children_busy(sb->s_root, bindex);
++	if (unlikely(err)) {
++		if (do_wh)
++			goto out_wh;
++		goto out;
++	}
++
++	err = 0;
++	br_id = br->br_id;
++	if (!remount)
++		au_br_do_del(sb, bindex, br);
++	else {
++		sysaufs_brs_del(sb, bindex);
++		au_br_do_del(sb, bindex, br);
++		sysaufs_brs_add(sb, bindex);
++	}
++
++	if (!bindex)
++		au_cpup_attr_all(sb->s_root->d_inode, /*force*/1);
++	else
++		au_sub_nlink(sb->s_root->d_inode, del->h_path.dentry->d_inode);
++	if (au_opt_test(mnt_flags, PLINK))
++		au_plink_half_refresh(sb, br_id);
++
++	if (sb->s_maxbytes == del->h_path.dentry->d_sb->s_maxbytes) {
++		bend--;
++		sb->s_maxbytes = 0;
++		for (bindex = 0; bindex <= bend; bindex++) {
++			unsigned long long maxb;
++
++			maxb = au_sbr_sb(sb, bindex)->s_maxbytes;
++			if (sb->s_maxbytes < maxb)
++				sb->s_maxbytes = maxb;
++		}
++	}
++
++	if (au_xino_brid(sb) == br->br_id)
++		au_xino_brid_set(sb, -1);
++	goto out; /* success */
++
++ out_wh:
++	/* revert */
++	rerr = au_br_init_wh(sb, br, br->br_perm, del->h_path.dentry);
++	if (rerr)
++		AuWarn("failed re-creating base whiteout, %s. (%d)\n",
++		       del->pathname, rerr);
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * change a branch permission
++ */
++
++static int do_need_sigen_inc(int a, int b)
++{
++	return au_br_whable(a) && !au_br_whable(b);
++}
++
++static int need_sigen_inc(int old, int new)
++{
++	return do_need_sigen_inc(old, new)
++		|| do_need_sigen_inc(new, old);
++}
++
++static int au_br_mod_files_ro(struct super_block *sb, aufs_bindex_t bindex)
++{
++	int err;
++	unsigned long n, ul, bytes, files;
++	aufs_bindex_t bstart;
++	struct file *file, *hf, **a;
++	const int step_bytes = 1024, /* memory allocation unit */
++		step_files = step_bytes / sizeof(*a);
++
++	err = -ENOMEM;
++	n = 0;
++	bytes = step_bytes;
++	files = step_files;
++	a = kmalloc(bytes, GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	/* no need file_list_lock() since sbinfo is locked? defered? */
++	list_for_each_entry(file, &sb->s_files, f_u.fu_list) {
++		if (special_file(file->f_dentry->d_inode->i_mode))
++			continue;
++
++		AuDbg("%.*s\n", AuDLNPair(file->f_dentry));
++		fi_read_lock(file);
++		if (unlikely(au_test_mmapped(file))) {
++			err = -EBUSY;
++			FiMustNoWaiters(file);
++			fi_read_unlock(file);
++			goto out_free;
++		}
++
++		bstart = au_fbstart(file);
++		if (!S_ISREG(file->f_dentry->d_inode->i_mode)
++		    || !(file->f_mode & FMODE_WRITE)
++		    || bstart != bindex) {
++			FiMustNoWaiters(file);
++			fi_read_unlock(file);
++			continue;
++		}
++
++		hf = au_h_fptr(file, bstart);
++		FiMustNoWaiters(file);
++		fi_read_unlock(file);
++
++		if (n < files)
++			a[n++] = hf;
++		else {
++			void *p;
++
++			err = -ENOMEM;
++			bytes += step_bytes;
++			files += step_files;
++			p = krealloc(a, bytes, GFP_NOFS);
++			if (p) {
++				a = p;
++				a[n++] = hf;
++			} else
++				goto out_free;
++		}
++	}
++
++	err = 0;
++	for (ul = 0; ul < n; ul++) {
++		/* todo: already flushed? */
++		hf = a[ul];
++		hf->f_flags = au_file_roflags(hf->f_flags);
++		hf->f_mode &= ~FMODE_WRITE;
++		file_release_write(hf);
++		mnt_drop_write(hf->f_vfsmnt);
++	}
++
++ out_free:
++	kfree(a);
++ out:
++	return err;
++}
++
++int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
++	      int *do_update)
++{
++	int err, rerr;
++	aufs_bindex_t bindex;
++	struct dentry *root;
++	struct au_branch *br;
++
++	root = sb->s_root;
++	au_plink_block_maintain(sb);
++	bindex = au_find_dbindex(root, mod->h_root);
++	if (bindex < 0) {
++		if (remount)
++			return 0; /* success */
++		err = -ENOENT;
++		AuErr("%s no such branch\n", mod->path);
++		goto out;
++	}
++	AuDbg("bindex b%d\n", bindex);
++
++	err = test_br(mod->h_root->d_inode, mod->perm, mod->path);
++	if (unlikely(err))
++		goto out;
++
++	br = au_sbr(sb, bindex);
++	if (br->br_perm == mod->perm)
++		return 0; /* success */
++
++	if (au_br_writable(br->br_perm)) {
++		/* remove whiteout base */
++		err = au_br_init_wh(sb, br, mod->perm, mod->h_root);
++		if (unlikely(err))
++			goto out;
++
++		if (!au_br_writable(mod->perm)) {
++			/* rw --> ro, file might be mmapped */
++			DiMustNoWaiters(root);
++			IiMustNoWaiters(root->d_inode);
++			di_write_unlock(root);
++			err = au_br_mod_files_ro(sb, bindex);
++			/* aufs_write_lock() calls ..._child() */
++			di_write_lock_child(root);
++
++			if (unlikely(err)) {
++				rerr = -ENOMEM;
++				br->br_wbr = kmalloc(sizeof(*br->br_wbr),
++						     GFP_NOFS);
++				if (br->br_wbr)
++					rerr = au_br_init_wh
++						(sb, br, br->br_perm,
++						 mod->h_root);
++				if (unlikely(rerr)) {
++					AuIOErr("nested error %d (%d)\n",
++						rerr, err);
++					br->br_perm = mod->perm;
++				}
++			}
++		}
++	} else if (au_br_writable(mod->perm)) {
++		/* ro --> rw */
++		err = -ENOMEM;
++		br->br_wbr = kmalloc(sizeof(*br->br_wbr), GFP_NOFS);
++		if (br->br_wbr) {
++			struct path path = {
++				.mnt	= br->br_mnt,
++				.dentry	= mod->h_root
++			};
++
++			err = au_wbr_init(br, sb, mod->perm, &path);
++			if (unlikely(err)) {
++				kfree(br->br_wbr);
++				br->br_wbr = NULL;
++			}
++		}
++	}
++
++	if (!err) {
++		*do_update |= need_sigen_inc(br->br_perm, mod->perm);
++		br->br_perm = mod->perm;
++	}
++
++ out:
++	return err;
++}
+diff -uNr test/fs/aufs/branch.h aufs2-standalone/fs/aufs/branch.h
+--- test/fs/aufs/branch.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/branch.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,200 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * branch filesystems and xino for them
++ */
++
++#ifndef __AUFS_BRANCH_H__
++#define __AUFS_BRANCH_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/mount.h>
++#include <linux/sysfs.h>
++#include <linux/aufs_type.h>
++#include "rwsem.h"
++#include "super.h"
++
++/* ---------------------------------------------------------------------- */
++
++/* a xino file */
++struct au_xino_file {
++	struct file		*xi_file;
++	struct mutex		xi_nondir_mtx;
++
++	/* todo: make xino files an array to support huge inode number */
++};
++
++/* members for writable branch only */
++enum {AuBrWh_BASE, AuBrWh_PLINK, AuBrWh_ORPH, AuBrWh_Last};
++struct au_wbr {
++	struct rw_semaphore	wbr_wh_rwsem;
++	struct dentry		*wbr_wh[AuBrWh_Last];
++	atomic_t 		wbr_wh_running;
++#define wbr_whbase		wbr_wh[AuBrWh_BASE]	/* whiteout base */
++#define wbr_plink		wbr_wh[AuBrWh_PLINK]	/* pseudo-link dir */
++#define wbr_orph		wbr_wh[AuBrWh_ORPH]	/* dir for orphans */
++
++	/* mfs mode */
++	unsigned long long	wbr_bytes;
++};
++
++/* protected by superblock rwsem */
++struct au_branch {
++	struct au_xino_file	br_xino;
++
++	aufs_bindex_t		br_id;
++
++	int			br_perm;
++	struct vfsmount		*br_mnt;
++	atomic_t		br_count;
++
++	struct au_wbr		*br_wbr;
++
++	/* xino truncation */
++	blkcnt_t		br_xino_upper;	/* watermark in blocks */
++	atomic_t		br_xino_running;
++
++#ifdef CONFIG_SYSFS
++	/* an entry under sysfs per mount-point */
++	char			br_name[8];
++	struct attribute	br_attr;
++#endif
++};
++
++/* ---------------------------------------------------------------------- */
++
++/* branch permission and attribute */
++enum {
++	AuBrPerm_RW,		/* writable, linkable wh */
++	AuBrPerm_RO,		/* readonly, no wh */
++	AuBrPerm_RR,		/* natively readonly, no wh */
++
++	AuBrPerm_RWNoLinkWH,	/* un-linkable whiteouts */
++
++	AuBrPerm_ROWH,		/* whiteout-able */
++	AuBrPerm_RRWH,		/* whiteout-able */
++
++	AuBrPerm_Last
++};
++
++static inline int au_br_writable(int brperm)
++{
++	return brperm == AuBrPerm_RW || brperm == AuBrPerm_RWNoLinkWH;
++}
++
++static inline int au_br_whable(int brperm)
++{
++	return brperm == AuBrPerm_RW
++		|| brperm == AuBrPerm_ROWH
++		|| brperm == AuBrPerm_RRWH;
++}
++
++static inline int au_br_rdonly(struct au_branch *br)
++{
++	return ((br->br_mnt->mnt_sb->s_flags & MS_RDONLY)
++		|| !au_br_writable(br->br_perm))
++		? -EROFS : 0;
++}
++
++static inline int au_br_hinotifyable(int brperm __maybe_unused)
++{
++#ifdef CONFIG_AUFS_HINOTIFY
++	return brperm != AuBrPerm_RR && brperm != AuBrPerm_RRWH;
++#else
++	return 0;
++#endif
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* branch.c */
++struct au_sbinfo;
++void au_br_free(struct au_sbinfo *sinfo);
++int au_br_index(struct super_block *sb, aufs_bindex_t br_id);
++struct au_opt_add;
++int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount);
++struct au_opt_del;
++int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount);
++struct au_opt_mod;
++int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
++	      int *do_update);
++
++/* xino.c */
++int au_xib_trunc(struct super_block *sb);
++ssize_t xino_fread(au_readf_t func, struct file *file, void *buf, size_t size,
++		   loff_t *pos);
++ssize_t xino_fwrite(au_writef_t func, struct file *file, void *buf, size_t size,
++		    loff_t *pos);
++struct file *au_xino_create(struct super_block *sb, char *fname, int silent);
++ino_t au_xino_new_ino(struct super_block *sb);
++int au_xino_write0(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		   ino_t ino);
++int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		  ino_t ino);
++int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		 ino_t *ino);
++int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t hino,
++	       struct file *base_file, int do_test);
++int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex);
++
++struct au_opt_xino;
++int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount);
++void au_xino_clr(struct super_block *sb);
++struct file *au_xino_def(struct super_block *sb);
++int au_xino_path(struct seq_file *seq, struct file *file);
++
++/* ---------------------------------------------------------------------- */
++
++/* Superblock to branch */
++static inline
++aufs_bindex_t au_sbr_id(struct super_block *sb, aufs_bindex_t bindex)
++{
++	return au_sbr(sb, bindex)->br_id;
++}
++
++static inline
++struct vfsmount *au_sbr_mnt(struct super_block *sb, aufs_bindex_t bindex)
++{
++	return au_sbr(sb, bindex)->br_mnt;
++}
++
++static inline
++struct super_block *au_sbr_sb(struct super_block *sb, aufs_bindex_t bindex)
++{
++	return au_sbr_mnt(sb, bindex)->mnt_sb;
++}
++
++static inline void au_sbr_put(struct super_block *sb, aufs_bindex_t bindex)
++{
++	atomic_dec(&au_sbr(sb, bindex)->br_count);
++}
++
++static inline int au_sbr_perm(struct super_block *sb, aufs_bindex_t bindex)
++{
++	return au_sbr(sb, bindex)->br_perm;
++}
++
++static inline int au_sbr_whable(struct super_block *sb, aufs_bindex_t bindex)
++{
++	return au_br_whable(au_sbr_perm(sb, bindex));
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * wbr_wh_read_lock, wbr_wh_write_lock
++ * wbr_wh_read_unlock, wbr_wh_write_unlock, wbr_wh_downgrade_lock
++ */
++AuSimpleRwsemFuncs(wbr_wh, struct au_wbr *wbr, &wbr->wbr_wh_rwsem);
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_BRANCH_H__ */
+diff -uNr test/fs/aufs/cpup.c aufs2-standalone/fs/aufs/cpup.c
+--- test/fs/aufs/cpup.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/cpup.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,1028 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * copy-up functions, see wbr_policy.c for copy-down
++ */
++
++#include <linux/fs_stack.h>
++#include <linux/uaccess.h>
++#include "aufs.h"
++
++void au_cpup_attr_flags(struct inode *dst, struct inode *src)
++{
++	const unsigned int mask = S_DEAD | S_SWAPFILE | S_PRIVATE
++		| S_NOATIME | S_NOCMTIME;
++
++	dst->i_flags |= src->i_flags & ~mask;
++	if (au_test_fs_notime(dst->i_sb))
++		dst->i_flags |= S_NOATIME | S_NOCMTIME;
++}
++
++void au_cpup_attr_timesizes(struct inode *inode)
++{
++	struct inode *h_inode;
++
++	h_inode = au_h_iptr(inode, au_ibstart(inode));
++	fsstack_copy_attr_times(inode, h_inode);
++	vfsub_copy_inode_size(inode, h_inode);
++}
++
++void au_cpup_attr_nlink(struct inode *inode, int force)
++{
++	struct inode *h_inode;
++	struct super_block *sb;
++	aufs_bindex_t bindex, bend;
++
++	sb = inode->i_sb;
++	bindex = au_ibstart(inode);
++	h_inode = au_h_iptr(inode, bindex);
++	if (!force
++	    && !S_ISDIR(h_inode->i_mode)
++	    && au_opt_test(au_mntflags(sb), PLINK)
++	    && au_plink_test(inode))
++		return;
++
++	inode->i_nlink = h_inode->i_nlink;
++
++	/*
++	 * fewer nlink makes find(1) noisy, but larger nlink doesn't.
++	 * it may includes whplink directory.
++	 */
++	if (S_ISDIR(h_inode->i_mode)) {
++		bend = au_ibend(inode);
++		for (bindex++; bindex <= bend; bindex++) {
++			h_inode = au_h_iptr(inode, bindex);
++			if (h_inode)
++				au_add_nlink(inode, h_inode);
++		}
++	}
++}
++
++void au_cpup_attr_changeable(struct inode *inode)
++{
++	struct inode *h_inode;
++
++	h_inode = au_h_iptr(inode, au_ibstart(inode));
++	inode->i_mode = h_inode->i_mode;
++	inode->i_uid = h_inode->i_uid;
++	inode->i_gid = h_inode->i_gid;
++	au_cpup_attr_timesizes(inode);
++	au_cpup_attr_flags(inode, h_inode);
++}
++
++void au_cpup_igen(struct inode *inode, struct inode *h_inode)
++{
++	struct au_iinfo *iinfo = au_ii(inode);
++
++	iinfo->ii_higen = h_inode->i_generation;
++	iinfo->ii_hsb1 = h_inode->i_sb;
++}
++
++void au_cpup_attr_all(struct inode *inode, int force)
++{
++	struct inode *h_inode;
++
++	h_inode = au_h_iptr(inode, au_ibstart(inode));
++	au_cpup_attr_changeable(inode);
++	if (inode->i_nlink > 0)
++		au_cpup_attr_nlink(inode, force);
++	inode->i_rdev = h_inode->i_rdev;
++	inode->i_blkbits = h_inode->i_blkbits;
++	au_cpup_igen(inode, h_inode);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* Note: dt_dentry and dt_h_dentry are not dget/dput-ed */
++
++/* keep the timestamps of the parent dir when cpup */
++void au_dtime_store(struct au_dtime *dt, struct dentry *dentry,
++		    struct path *h_path)
++{
++	struct inode *h_inode;
++
++	dt->dt_dentry = dentry;
++	dt->dt_h_path = *h_path;
++	h_inode = h_path->dentry->d_inode;
++	dt->dt_atime = h_inode->i_atime;
++	dt->dt_mtime = h_inode->i_mtime;
++	/* smp_mb(); */
++}
++
++void au_dtime_revert(struct au_dtime *dt)
++{
++	struct iattr attr;
++	int err;
++
++	attr.ia_atime = dt->dt_atime;
++	attr.ia_mtime = dt->dt_mtime;
++	attr.ia_valid = ATTR_FORCE | ATTR_MTIME | ATTR_MTIME_SET
++		| ATTR_ATIME | ATTR_ATIME_SET;
++
++	err = vfsub_notify_change(&dt->dt_h_path, &attr);
++	if (unlikely(err))
++		AuWarn("restoring timestamps failed(%d). ignored\n", err);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static noinline_for_stack
++int cpup_iattr(struct dentry *dst, aufs_bindex_t bindex, struct dentry *h_src)
++{
++	int err, sbits;
++	struct iattr ia;
++	struct path h_path;
++	struct inode *h_isrc;
++
++	h_path.dentry = au_h_dptr(dst, bindex);
++	h_path.mnt = au_sbr_mnt(dst->d_sb, bindex);
++	h_isrc = h_src->d_inode;
++	ia.ia_valid = ATTR_FORCE | ATTR_MODE | ATTR_UID | ATTR_GID
++		| ATTR_ATIME | ATTR_MTIME
++		| ATTR_ATIME_SET | ATTR_MTIME_SET;
++	ia.ia_mode = h_isrc->i_mode;
++	ia.ia_uid = h_isrc->i_uid;
++	ia.ia_gid = h_isrc->i_gid;
++	ia.ia_atime = h_isrc->i_atime;
++	ia.ia_mtime = h_isrc->i_mtime;
++	sbits = !!(ia.ia_mode & (S_ISUID | S_ISGID));
++	au_cpup_attr_flags(h_path.dentry->d_inode, h_isrc);
++	err = vfsub_notify_change(&h_path, &ia);
++
++	/* is this nfs only? */
++	if (!err && sbits && au_test_nfs(h_path.dentry->d_sb)) {
++		ia.ia_valid = ATTR_FORCE | ATTR_MODE;
++		ia.ia_mode = h_isrc->i_mode;
++		err = vfsub_notify_change(&h_path, &ia);
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_do_copy_file(struct file *dst, struct file *src, loff_t len,
++			   char *buf, unsigned long blksize)
++{
++	int err;
++	size_t sz, rbytes, wbytes;
++	unsigned char all_zero;
++	char *p, *zp;
++	struct mutex *h_mtx;
++	/* reduce stack usage */
++	struct iattr *ia;
++
++	zp = page_address(ZERO_PAGE(0));
++	if (unlikely(!zp))
++		return -ENOMEM; /* possible? */
++
++	err = 0;
++	all_zero = 0;
++	while (len) {
++		AuDbg("len %lld\n", len);
++		sz = blksize;
++		if (len < blksize)
++			sz = len;
++
++		rbytes = 0;
++		/* todo: signal_pending? */
++		while (!rbytes || err == -EAGAIN || err == -EINTR) {
++			rbytes = vfsub_read_k(src, buf, sz, &src->f_pos);
++			err = rbytes;
++		}
++		if (unlikely(err < 0))
++			break;
++
++		all_zero = 0;
++		if (len >= rbytes && rbytes == blksize)
++			all_zero = !memcmp(buf, zp, rbytes);
++		if (!all_zero) {
++			wbytes = rbytes;
++			p = buf;
++			while (wbytes) {
++				size_t b;
++
++				b = vfsub_write_k(dst, p, wbytes, &dst->f_pos);
++				err = b;
++				/* todo: signal_pending? */
++				if (unlikely(err == -EAGAIN || err == -EINTR))
++					continue;
++				if (unlikely(err < 0))
++					break;
++				wbytes -= b;
++				p += b;
++			}
++		} else {
++			loff_t res;
++
++			AuLabel(hole);
++			res = vfsub_llseek(dst, rbytes, SEEK_CUR);
++			err = res;
++			if (unlikely(res < 0))
++				break;
++		}
++		len -= rbytes;
++		err = 0;
++	}
++
++	/* the last block may be a hole */
++	if (!err && all_zero) {
++		AuLabel(last hole);
++
++		err = 1;
++		if (au_test_nfs(dst->f_dentry->d_sb)) {
++			/* nfs requires this step to make last hole */
++			/* is this only nfs? */
++			do {
++				/* todo: signal_pending? */
++				err = vfsub_write_k(dst, "\0", 1, &dst->f_pos);
++			} while (err == -EAGAIN || err == -EINTR);
++			if (err == 1)
++				dst->f_pos--;
++		}
++
++		if (err == 1) {
++			ia = (void *)buf;
++			ia->ia_size = dst->f_pos;
++			ia->ia_valid = ATTR_SIZE | ATTR_FILE;
++			ia->ia_file = dst;
++			h_mtx = &dst->f_dentry->d_inode->i_mutex;
++			mutex_lock_nested(h_mtx, AuLsc_I_CHILD2);
++			err = vfsub_notify_change(&dst->f_path, ia);
++			mutex_unlock(h_mtx);
++		}
++	}
++
++	return err;
++}
++
++int au_copy_file(struct file *dst, struct file *src, loff_t len)
++{
++	int err;
++	unsigned long blksize;
++	unsigned char do_kfree;
++	char *buf;
++
++	err = -ENOMEM;
++	blksize = dst->f_dentry->d_sb->s_blocksize;
++	if (!blksize || PAGE_SIZE < blksize)
++		blksize = PAGE_SIZE;
++	AuDbg("blksize %lu\n", blksize);
++	do_kfree = (blksize != PAGE_SIZE && blksize >= sizeof(struct iattr *));
++	if (do_kfree)
++		buf = kmalloc(blksize, GFP_NOFS);
++	else
++		buf = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!buf))
++		goto out;
++
++	if (len > (1 << 22))
++		AuDbg("copying a large file %lld\n", (long long)len);
++
++	src->f_pos = 0;
++	dst->f_pos = 0;
++	err = au_do_copy_file(dst, src, len, buf, blksize);
++	if (do_kfree)
++		kfree(buf);
++	else
++		free_page((unsigned long)buf);
++
++ out:
++	return err;
++}
++
++/*
++ * to support a sparse file which is opened with O_APPEND,
++ * we need to close the file.
++ */
++static int au_cp_regular(struct dentry *dentry, aufs_bindex_t bdst,
++			aufs_bindex_t bsrc, loff_t len)
++{
++	int err, i;
++	enum { SRC, DST };
++	struct {
++		aufs_bindex_t bindex;
++		unsigned int flags;
++		struct dentry *dentry;
++		struct file *file;
++		void *label, *label_file;
++	} *f, file[] = {
++		{
++			.bindex = bsrc,
++			.flags = O_RDONLY | O_NOATIME | O_LARGEFILE,
++			.file = NULL,
++			.label = &&out,
++			.label_file = &&out_src
++		},
++		{
++			.bindex = bdst,
++			.flags = O_WRONLY | O_NOATIME | O_LARGEFILE,
++			.file = NULL,
++			.label = &&out_src,
++			.label_file = &&out_dst
++		}
++	};
++	struct super_block *sb;
++
++	/* bsrc branch can be ro/rw. */
++	sb = dentry->d_sb;
++	f = file;
++	for (i = 0; i < 2; i++, f++) {
++		f->dentry = au_h_dptr(dentry, f->bindex);
++		f->file = au_h_open(dentry, f->bindex, f->flags, /*file*/NULL);
++		err = PTR_ERR(f->file);
++		if (IS_ERR(f->file))
++			goto *f->label;
++		err = -EINVAL;
++		if (unlikely(!f->file->f_op))
++			goto *f->label_file;
++	}
++
++	/* try stopping to update while we copyup */
++	IMustLock(file[SRC].dentry->d_inode);
++	err = au_copy_file(file[DST].file, file[SRC].file, len);
++
++ out_dst:
++	fput(file[DST].file);
++	au_sbr_put(sb, file[DST].bindex);
++ out_src:
++	fput(file[SRC].file);
++	au_sbr_put(sb, file[SRC].bindex);
++ out:
++	return err;
++}
++
++static int au_do_cpup_regular(struct dentry *dentry, aufs_bindex_t bdst,
++			      aufs_bindex_t bsrc, loff_t len,
++			      struct inode *h_dir, struct path *h_path)
++{
++	int err, rerr;
++	loff_t l;
++
++	err = 0;
++	l = i_size_read(au_h_iptr(dentry->d_inode, bsrc));
++	if (len == -1 || l < len)
++		len = l;
++	if (len)
++		err = au_cp_regular(dentry, bdst, bsrc, len);
++	if (!err)
++		goto out; /* success */
++
++	rerr = vfsub_unlink(h_dir, h_path, /*force*/0);
++	if (rerr) {
++		AuIOErr("failed unlinking cpup-ed %.*s(%d, %d)\n",
++			AuDLNPair(h_path->dentry), err, rerr);
++		err = -EIO;
++	}
++
++ out:
++	return err;
++}
++
++static int au_do_cpup_symlink(struct path *h_path, struct dentry *h_src,
++			      struct inode *h_dir)
++{
++	int err, symlen;
++	mm_segment_t old_fs;
++	char *sym;
++
++	err = -ENOSYS;
++	if (unlikely(!h_src->d_inode->i_op->readlink))
++		goto out;
++
++	err = -ENOMEM;
++	sym = __getname();
++	if (unlikely(!sym))
++		goto out;
++
++	old_fs = get_fs();
++	set_fs(KERNEL_DS);
++	symlen = h_src->d_inode->i_op->readlink(h_src, (char __user *)sym,
++						PATH_MAX);
++	err = symlen;
++	set_fs(old_fs);
++
++	if (symlen > 0) {
++		sym[symlen] = 0;
++		err = vfsub_symlink(h_dir, h_path, sym);
++	}
++	__putname(sym);
++
++ out:
++	return err;
++}
++
++/* return with the lower dst inode is locked */
++static noinline_for_stack
++int cpup_entry(struct dentry *dentry, aufs_bindex_t bdst,
++	       aufs_bindex_t bsrc, loff_t len, unsigned int flags,
++	       struct dentry *dst_parent)
++{
++	int err;
++	umode_t mode;
++	unsigned int mnt_flags;
++	unsigned char isdir;
++	const unsigned char do_dt = !!au_ftest_cpup(flags, DTIME);
++	struct au_dtime dt;
++	struct path h_path;
++	struct dentry *h_src, *h_dst, *h_parent;
++	struct inode *h_inode, *h_dir;
++	struct super_block *sb;
++
++	/* bsrc branch can be ro/rw. */
++	h_src = au_h_dptr(dentry, bsrc);
++	h_inode = h_src->d_inode;
++	AuDebugOn(h_inode != au_h_iptr(dentry->d_inode, bsrc));
++
++	/* try stopping to be referenced while we are creating */
++	h_dst = au_h_dptr(dentry, bdst);
++	h_parent = h_dst->d_parent; /* dir inode is locked */
++	h_dir = h_parent->d_inode;
++	IMustLock(h_dir);
++	AuDebugOn(h_parent != h_dst->d_parent);
++
++	sb = dentry->d_sb;
++	h_path.mnt = au_sbr_mnt(sb, bdst);
++	if (do_dt) {
++		h_path.dentry = h_parent;
++		au_dtime_store(&dt, dst_parent, &h_path);
++	}
++	h_path.dentry = h_dst;
++
++	isdir = 0;
++	mode = h_inode->i_mode;
++	switch (mode & S_IFMT) {
++	case S_IFREG:
++		/* try stopping to update while we are referencing */
++		IMustLock(h_inode);
++		err = vfsub_create(h_dir, &h_path, mode | S_IWUSR);
++		if (!err)
++			err = au_do_cpup_regular
++				(dentry, bdst, bsrc, len,
++				 au_h_iptr(dst_parent->d_inode, bdst), &h_path);
++		break;
++	case S_IFDIR:
++		isdir = 1;
++		err = vfsub_mkdir(h_dir, &h_path, mode);
++		if (!err) {
++			/*
++			 * strange behaviour from the users view,
++			 * particularry setattr case
++			 */
++			if (au_ibstart(dst_parent->d_inode) == bdst)
++				au_cpup_attr_nlink(dst_parent->d_inode,
++						   /*force*/1);
++			au_cpup_attr_nlink(dentry->d_inode, /*force*/1);
++		}
++		break;
++	case S_IFLNK:
++		err = au_do_cpup_symlink(&h_path, h_src, h_dir);
++		break;
++	case S_IFCHR:
++	case S_IFBLK:
++		AuDebugOn(!capable(CAP_MKNOD));
++		/*FALLTHROUGH*/
++	case S_IFIFO:
++	case S_IFSOCK:
++		err = vfsub_mknod(h_dir, &h_path, mode, h_inode->i_rdev);
++		break;
++	default:
++		AuIOErr("Unknown inode type 0%o\n", mode);
++		err = -EIO;
++	}
++
++	mnt_flags = au_mntflags(sb);
++	if (!au_opt_test(mnt_flags, UDBA_NONE)
++	    && !isdir
++	    && au_opt_test(mnt_flags, XINO)
++	    && h_inode->i_nlink == 1
++	    /* todo: unnecessary? */
++	    /* && dentry->d_inode->i_nlink == 1 */
++	    && bdst < bsrc
++	    && !au_ftest_cpup(flags, KEEPLINO))
++		au_xino_write0(sb, bsrc, h_inode->i_ino, /*ino*/0);
++		/* ignore this error */
++
++	if (do_dt)
++		au_dtime_revert(&dt);
++	return err;
++}
++
++/*
++ * copyup the @dentry from @bsrc to @bdst.
++ * the caller must set the both of lower dentries.
++ * @len is for truncating when it is -1 copyup the entire file.
++ * in link/rename cases, @dst_parent may be different from the real one.
++ */
++static int au_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
++			  aufs_bindex_t bsrc, loff_t len, unsigned int flags,
++			  struct dentry *dst_parent)
++{
++	int err, rerr;
++	aufs_bindex_t old_ibstart;
++	unsigned char isdir, plink;
++	struct au_dtime dt;
++	struct path h_path;
++	struct dentry *h_src, *h_dst, *h_parent;
++	struct inode *dst_inode, *h_dir, *inode;
++	struct super_block *sb;
++
++	AuDebugOn(bsrc <= bdst);
++
++	sb = dentry->d_sb;
++	h_path.mnt = au_sbr_mnt(sb, bdst);
++	h_dst = au_h_dptr(dentry, bdst);
++	h_parent = h_dst->d_parent; /* dir inode is locked */
++	h_dir = h_parent->d_inode;
++	IMustLock(h_dir);
++
++	h_src = au_h_dptr(dentry, bsrc);
++	inode = dentry->d_inode;
++
++	if (!dst_parent)
++		dst_parent = dget_parent(dentry);
++	else
++		dget(dst_parent);
++
++	plink = !!au_opt_test(au_mntflags(sb), PLINK);
++	dst_inode = au_h_iptr(inode, bdst);
++	if (dst_inode) {
++		if (unlikely(!plink)) {
++			err = -EIO;
++			AuIOErr("i%lu exists on a upper branch "
++				"but plink is disabled\n", inode->i_ino);
++			goto out;
++		}
++
++		if (dst_inode->i_nlink) {
++			const int do_dt = au_ftest_cpup(flags, DTIME);
++
++			h_src = au_plink_lkup(inode, bdst);
++			err = PTR_ERR(h_src);
++			if (IS_ERR(h_src))
++				goto out;
++			if (unlikely(!h_src->d_inode)) {
++				err = -EIO;
++				AuIOErr("i%lu exists on a upper branch "
++					"but plink is broken\n", inode->i_ino);
++				dput(h_src);
++				goto out;
++			}
++
++			if (do_dt) {
++				h_path.dentry = h_parent;
++				au_dtime_store(&dt, dst_parent, &h_path);
++			}
++			h_path.dentry = h_dst;
++			err = vfsub_link(h_src, h_dir, &h_path);
++			if (do_dt)
++				au_dtime_revert(&dt);
++			dput(h_src);
++			goto out;
++		} else
++			/* todo: cpup_wh_file? */
++			/* udba work */
++			au_update_brange(inode, 1);
++	}
++
++	old_ibstart = au_ibstart(inode);
++	err = cpup_entry(dentry, bdst, bsrc, len, flags, dst_parent);
++	if (unlikely(err))
++		goto out;
++	dst_inode = h_dst->d_inode;
++	mutex_lock_nested(&dst_inode->i_mutex, AuLsc_I_CHILD2);
++
++	err = cpup_iattr(dentry, bdst, h_src);
++	isdir = S_ISDIR(dst_inode->i_mode);
++	if (!err) {
++		if (bdst < old_ibstart)
++			au_set_ibstart(inode, bdst);
++		au_set_h_iptr(inode, bdst, au_igrab(dst_inode),
++			      au_hi_flags(inode, isdir));
++		mutex_unlock(&dst_inode->i_mutex);
++		if (!isdir
++		    && h_src->d_inode->i_nlink > 1
++		    && plink)
++			au_plink_append(inode, bdst, h_dst);
++		goto out; /* success */
++	}
++
++	/* revert */
++	h_path.dentry = h_parent;
++	mutex_unlock(&dst_inode->i_mutex);
++	au_dtime_store(&dt, dst_parent, &h_path);
++	h_path.dentry = h_dst;
++	if (!isdir)
++		rerr = vfsub_unlink(h_dir, &h_path, /*force*/0);
++	else
++		rerr = vfsub_rmdir(h_dir, &h_path);
++	au_dtime_revert(&dt);
++	if (rerr) {
++		AuIOErr("failed removing broken entry(%d, %d)\n", err, rerr);
++		err = -EIO;
++	}
++
++ out:
++	dput(dst_parent);
++	return err;
++}
++
++struct au_cpup_single_args {
++	int *errp;
++	struct dentry *dentry;
++	aufs_bindex_t bdst, bsrc;
++	loff_t len;
++	unsigned int flags;
++	struct dentry *dst_parent;
++};
++
++static void au_call_cpup_single(void *args)
++{
++	struct au_cpup_single_args *a = args;
++	*a->errp = au_cpup_single(a->dentry, a->bdst, a->bsrc, a->len,
++				  a->flags, a->dst_parent);
++}
++
++int au_sio_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
++		       aufs_bindex_t bsrc, loff_t len, unsigned int flags,
++		       struct dentry *dst_parent)
++{
++	int err, wkq_err;
++	umode_t mode;
++	struct dentry *h_dentry;
++
++	h_dentry = au_h_dptr(dentry, bsrc);
++	mode = h_dentry->d_inode->i_mode & S_IFMT;
++	if ((mode != S_IFCHR && mode != S_IFBLK)
++	    || capable(CAP_MKNOD))
++		err = au_cpup_single(dentry, bdst, bsrc, len, flags,
++				     dst_parent);
++	else {
++		struct au_cpup_single_args args = {
++			.errp		= &err,
++			.dentry		= dentry,
++			.bdst		= bdst,
++			.bsrc		= bsrc,
++			.len		= len,
++			.flags		= flags,
++			.dst_parent	= dst_parent
++		};
++		wkq_err = au_wkq_wait(au_call_cpup_single, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	return err;
++}
++
++/*
++ * copyup the @dentry from the first active lower branch to @bdst,
++ * using au_cpup_single().
++ */
++static int au_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
++			  unsigned int flags)
++{
++	int err;
++	aufs_bindex_t bsrc, bend;
++
++	bend = au_dbend(dentry);
++	for (bsrc = bdst + 1; bsrc <= bend; bsrc++)
++		if (au_h_dptr(dentry, bsrc))
++			break;
++
++	err = au_lkup_neg(dentry, bdst);
++	if (!err) {
++		err = au_cpup_single(dentry, bdst, bsrc, len, flags, NULL);
++		if (!err)
++			return 0; /* success */
++
++		/* revert */
++		au_set_h_dptr(dentry, bdst, NULL);
++		au_set_dbstart(dentry, bsrc);
++	}
++
++	return err;
++}
++
++struct au_cpup_simple_args {
++	int *errp;
++	struct dentry *dentry;
++	aufs_bindex_t bdst;
++	loff_t len;
++	unsigned int flags;
++};
++
++static void au_call_cpup_simple(void *args)
++{
++	struct au_cpup_simple_args *a = args;
++	*a->errp = au_cpup_simple(a->dentry, a->bdst, a->len, a->flags);
++}
++
++int au_sio_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
++		       unsigned int flags)
++{
++	int err, wkq_err;
++	unsigned char do_sio;
++	struct dentry *parent;
++	struct inode *h_dir;
++
++	parent = dget_parent(dentry);
++	h_dir = au_h_iptr(parent->d_inode, bdst);
++	do_sio = !!au_test_h_perm_sio(h_dir, MAY_EXEC | MAY_WRITE);
++	if (!do_sio) {
++		/*
++		 * testing CAP_MKNOD is for generic fs,
++		 * but CAP_FSETID is for xfs only, currently.
++		 */
++		umode_t mode = dentry->d_inode->i_mode;
++		do_sio = (((mode & (S_IFCHR | S_IFBLK))
++			   && !capable(CAP_MKNOD))
++			  || ((mode & (S_ISUID | S_ISGID))
++			      && !capable(CAP_FSETID)));
++	}
++	if (!do_sio)
++		err = au_cpup_simple(dentry, bdst, len, flags);
++	else {
++		struct au_cpup_simple_args args = {
++			.errp		= &err,
++			.dentry		= dentry,
++			.bdst		= bdst,
++			.len		= len,
++			.flags		= flags
++		};
++		wkq_err = au_wkq_wait(au_call_cpup_simple, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	dput(parent);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * copyup the deleted file for writing.
++ */
++static int au_do_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst,
++			 struct dentry *wh_dentry, struct file *file,
++			 loff_t len)
++{
++	int err;
++	aufs_bindex_t bstart;
++	struct au_dinfo *dinfo;
++	struct dentry *h_d_dst, *h_d_start;
++
++	dinfo = au_di(dentry);
++	bstart = dinfo->di_bstart;
++	h_d_dst = dinfo->di_hdentry[0 + bdst].hd_dentry;
++	dinfo->di_bstart = bdst;
++	dinfo->di_hdentry[0 + bdst].hd_dentry = wh_dentry;
++	h_d_start = dinfo->di_hdentry[0 + bstart].hd_dentry;
++	if (file)
++		dinfo->di_hdentry[0 + bstart].hd_dentry
++			= au_h_fptr(file, au_fbstart(file))->f_dentry;
++	err = au_cpup_single(dentry, bdst, bstart, len, !AuCpup_DTIME,
++			     /*h_parent*/NULL);
++	if (!err && file) {
++		err = au_reopen_nondir(file);
++		dinfo->di_hdentry[0 + bstart].hd_dentry = h_d_start;
++	}
++	dinfo->di_hdentry[0 + bdst].hd_dentry = h_d_dst;
++	dinfo->di_bstart = bstart;
++
++	return err;
++}
++
++static int au_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
++		      struct file *file)
++{
++	int err;
++	struct au_dtime dt;
++	struct dentry *parent, *h_parent, *wh_dentry;
++	struct au_branch *br;
++	struct path h_path;
++
++	br = au_sbr(dentry->d_sb, bdst);
++	parent = dget_parent(dentry);
++	h_parent = au_h_dptr(parent, bdst);
++	wh_dentry = au_whtmp_lkup(h_parent, br, &dentry->d_name);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out;
++
++	h_path.dentry = h_parent;
++	h_path.mnt = br->br_mnt;
++	au_dtime_store(&dt, parent, &h_path);
++	err = au_do_cpup_wh(dentry, bdst, wh_dentry, file, len);
++	if (unlikely(err))
++		goto out_wh;
++
++	dget(wh_dentry);
++	h_path.dentry = wh_dentry;
++	err = vfsub_unlink(h_parent->d_inode, &h_path, /*force*/0);
++	if (unlikely(err)) {
++		AuIOErr("failed remove copied-up tmp file %.*s(%d)\n",
++			AuDLNPair(wh_dentry), err);
++		err = -EIO;
++	}
++	au_dtime_revert(&dt);
++	au_set_hi_wh(dentry->d_inode, bdst, wh_dentry);
++
++ out_wh:
++	dput(wh_dentry);
++ out:
++	dput(parent);
++	return err;
++}
++
++struct au_cpup_wh_args {
++	int *errp;
++	struct dentry *dentry;
++	aufs_bindex_t bdst;
++	loff_t len;
++	struct file *file;
++};
++
++static void au_call_cpup_wh(void *args)
++{
++	struct au_cpup_wh_args *a = args;
++	*a->errp = au_cpup_wh(a->dentry, a->bdst, a->len, a->file);
++}
++
++int au_sio_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
++		   struct file *file)
++{
++	int err, wkq_err;
++	struct dentry *parent, *h_orph, *h_parent, *h_dentry;
++	struct inode *dir, *h_dir, *h_tmpdir, *h_inode;
++	struct au_wbr *wbr;
++
++	parent = dget_parent(dentry);
++	dir = parent->d_inode;
++	h_orph = NULL;
++	h_parent = NULL;
++	h_dir = au_igrab(au_h_iptr(dir, bdst));
++	h_tmpdir = h_dir;
++	if (!h_dir->i_nlink) {
++		wbr = au_sbr(dentry->d_sb, bdst)->br_wbr;
++		h_orph = wbr->wbr_orph;
++
++		h_parent = dget(au_h_dptr(parent, bdst));
++		au_set_h_dptr(parent, bdst, NULL);
++		au_set_h_dptr(parent, bdst, dget(h_orph));
++		h_tmpdir = h_orph->d_inode;
++		au_set_h_iptr(dir, bdst, NULL, 0);
++		au_set_h_iptr(dir, bdst, au_igrab(h_tmpdir), /*flags*/0);
++
++		/* this temporary unlock is safe */
++		if (file)
++			h_dentry = au_h_fptr(file, au_fbstart(file))->f_dentry;
++		else
++			h_dentry = au_h_dptr(dentry, au_dbstart(dentry));
++		h_inode = h_dentry->d_inode;
++		IMustLock(h_inode);
++		mutex_unlock(&h_inode->i_mutex);
++		mutex_lock_nested(&h_tmpdir->i_mutex, AuLsc_I_PARENT2);
++		mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++	}
++
++	if (!au_test_h_perm_sio(h_tmpdir, MAY_EXEC | MAY_WRITE))
++		err = au_cpup_wh(dentry, bdst, len, file);
++	else {
++		struct au_cpup_wh_args args = {
++			.errp	= &err,
++			.dentry	= dentry,
++			.bdst	= bdst,
++			.len	= len,
++			.file	= file
++		};
++		wkq_err = au_wkq_wait(au_call_cpup_wh, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	if (h_orph) {
++		mutex_unlock(&h_tmpdir->i_mutex);
++		au_set_h_iptr(dir, bdst, NULL, 0);
++		au_set_h_iptr(dir, bdst, au_igrab(h_dir), /*flags*/0);
++		au_set_h_dptr(parent, bdst, NULL);
++		au_set_h_dptr(parent, bdst, h_parent);
++	}
++	iput(h_dir);
++	dput(parent);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * generic routine for both of copy-up and copy-down.
++ */
++/* cf. revalidate function in file.c */
++int au_cp_dirs(struct dentry *dentry, aufs_bindex_t bdst,
++	       int (*cp)(struct dentry *dentry, aufs_bindex_t bdst,
++			 struct dentry *h_parent, void *arg),
++	       void *arg)
++{
++	int err;
++	struct au_pin pin;
++	struct dentry *d, *parent, *h_parent, *real_parent;
++
++	err = 0;
++	parent = dget_parent(dentry);
++	if (IS_ROOT(parent))
++		goto out;
++
++	au_pin_init(&pin, dentry, bdst, AuLsc_DI_PARENT2, AuLsc_I_PARENT2,
++		    au_opt_udba(dentry->d_sb), AuPin_MNT_WRITE);
++
++	/* do not use au_dpage */
++	real_parent = parent;
++	while (1) {
++		dput(parent);
++		parent = dget_parent(dentry);
++		h_parent = au_h_dptr(parent, bdst);
++		if (h_parent)
++			goto out; /* success */
++
++		/* find top dir which is necessary to cpup */
++		do {
++			d = parent;
++			dput(parent);
++			parent = dget_parent(d);
++			di_read_lock_parent3(parent, !AuLock_IR);
++			h_parent = au_h_dptr(parent, bdst);
++			di_read_unlock(parent, !AuLock_IR);
++		} while (!h_parent);
++
++		if (d != real_parent)
++			di_write_lock_child3(d);
++
++		/* somebody else might create while we were sleeping */
++		if (!au_h_dptr(d, bdst) || !au_h_dptr(d, bdst)->d_inode) {
++			if (au_h_dptr(d, bdst))
++				au_update_dbstart(d);
++
++			au_pin_set_dentry(&pin, d);
++			err = au_do_pin(&pin);
++			if (!err) {
++				err = cp(d, bdst, h_parent, arg);
++				au_unpin(&pin);
++			}
++		}
++
++		if (d != real_parent)
++			di_write_unlock(d);
++		if (unlikely(err))
++			break;
++	}
++
++ out:
++	dput(parent);
++	return err;
++}
++
++static int au_cpup_dir(struct dentry *dentry, aufs_bindex_t bdst,
++		       struct dentry *h_parent __maybe_unused ,
++		       void *arg __maybe_unused)
++{
++	return au_sio_cpup_simple(dentry, bdst, -1, AuCpup_DTIME);
++}
++
++int au_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst)
++{
++	return au_cp_dirs(dentry, bdst, au_cpup_dir, NULL);
++}
++
++int au_test_and_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst)
++{
++	int err;
++	struct dentry *parent;
++	struct inode *dir;
++
++	parent = dget_parent(dentry);
++	dir = parent->d_inode;
++	err = 0;
++	if (au_h_iptr(dir, bdst))
++		goto out;
++
++	di_read_unlock(parent, AuLock_IR);
++	di_write_lock_parent(parent);
++	/* someone else might change our inode while we were sleeping */
++	if (!au_h_iptr(dir, bdst))
++		err = au_cpup_dirs(dentry, bdst);
++	di_downgrade_lock(parent, AuLock_IR);
++
++ out:
++	dput(parent);
++	return err;
++}
+diff -uNr test/fs/aufs/cpup.h aufs2-standalone/fs/aufs/cpup.h
+--- test/fs/aufs/cpup.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/cpup.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,68 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * copy-up/down functions
++ */
++
++#ifndef __AUFS_CPUP_H__
++#define __AUFS_CPUP_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/aufs_type.h>
++
++void au_cpup_attr_flags(struct inode *dst, struct inode *src);
++void au_cpup_attr_timesizes(struct inode *inode);
++void au_cpup_attr_nlink(struct inode *inode, int force);
++void au_cpup_attr_changeable(struct inode *inode);
++void au_cpup_igen(struct inode *inode, struct inode *h_inode);
++void au_cpup_attr_all(struct inode *inode, int force);
++
++/* ---------------------------------------------------------------------- */
++
++/* cpup flags */
++#define AuCpup_DTIME	1		/* do dtime_store/revert */
++#define AuCpup_KEEPLINO	(1 << 1)	/* do not clear the lower xino,
++					   for link(2) */
++#define au_ftest_cpup(flags, name)	((flags) & AuCpup_##name)
++#define au_fset_cpup(flags, name)	{ (flags) |= AuCpup_##name; }
++#define au_fclr_cpup(flags, name)	{ (flags) &= ~AuCpup_##name; }
++
++int au_copy_file(struct file *dst, struct file *src, loff_t len);
++int au_sio_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
++		       aufs_bindex_t bsrc, loff_t len, unsigned int flags,
++		       struct dentry *dst_parent);
++int au_sio_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
++		       unsigned int flags);
++int au_sio_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
++		   struct file *file);
++
++int au_cp_dirs(struct dentry *dentry, aufs_bindex_t bdst,
++	       int (*cp)(struct dentry *dentry, aufs_bindex_t bdst,
++			 struct dentry *h_parent, void *arg),
++	       void *arg);
++int au_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst);
++int au_test_and_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst);
++
++/* ---------------------------------------------------------------------- */
++
++/* keep timestamps when copyup */
++struct au_dtime {
++	struct dentry *dt_dentry;
++	struct path dt_h_path;
++	struct timespec dt_atime, dt_mtime;
++};
++void au_dtime_store(struct au_dtime *dt, struct dentry *dentry,
++		    struct path *h_path);
++void au_dtime_revert(struct au_dtime *dt);
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_CPUP_H__ */
+diff -uNr test/fs/aufs/dcsub.c aufs2-standalone/fs/aufs/dcsub.c
+--- test/fs/aufs/dcsub.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/dcsub.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,214 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * sub-routines for dentry cache
++ */
++
++#include "aufs.h"
++
++static void au_dpage_free(struct au_dpage *dpage)
++{
++	int i;
++	struct dentry **p;
++
++	p = dpage->dentries;
++	for (i = 0; i < dpage->ndentry; i++)
++		dput(*p++);
++	free_page((unsigned long)dpage->dentries);
++}
++
++int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp)
++{
++	int err;
++	void *p;
++
++	err = -ENOMEM;
++	dpages->dpages = kmalloc(sizeof(*dpages->dpages), gfp);
++	if (unlikely(!dpages->dpages))
++		goto out;
++
++	p = (void *)__get_free_page(gfp);
++	if (unlikely(!p))
++		goto out_dpages;
++
++	dpages->dpages[0].ndentry = 0;
++	dpages->dpages[0].dentries = p;
++	dpages->ndpage = 1;
++	return 0; /* success */
++
++ out_dpages:
++	kfree(dpages->dpages);
++ out:
++	return err;
++}
++
++void au_dpages_free(struct au_dcsub_pages *dpages)
++{
++	int i;
++	struct au_dpage *p;
++
++	p = dpages->dpages;
++	for (i = 0; i < dpages->ndpage; i++)
++		au_dpage_free(p++);
++	kfree(dpages->dpages);
++}
++
++static int au_dpages_append(struct au_dcsub_pages *dpages,
++			    struct dentry *dentry, gfp_t gfp)
++{
++	int err, sz;
++	struct au_dpage *dpage;
++	void *p;
++
++	dpage = dpages->dpages + dpages->ndpage - 1;
++	sz = PAGE_SIZE / sizeof(dentry);
++	if (unlikely(dpage->ndentry >= sz)) {
++		AuLabel(new dpage);
++		err = -ENOMEM;
++		sz = dpages->ndpage * sizeof(*dpages->dpages);
++		p = au_kzrealloc(dpages->dpages, sz,
++				 sz + sizeof(*dpages->dpages), gfp);
++		if (unlikely(!p))
++			goto out;
++
++		dpages->dpages = p;
++		dpage = dpages->dpages + dpages->ndpage;
++		p = (void *)__get_free_page(gfp);
++		if (unlikely(!p))
++			goto out;
++
++		dpage->ndentry = 0;
++		dpage->dentries = p;
++		dpages->ndpage++;
++	}
++
++	dpage->dentries[dpage->ndentry++] = dget(dentry);
++	return 0; /* success */
++
++ out:
++	return err;
++}
++
++int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
++		   au_dpages_test test, void *arg)
++{
++	int err;
++	struct dentry *this_parent = root;
++	struct list_head *next;
++	struct super_block *sb = root->d_sb;
++
++	err = 0;
++	spin_lock(&dcache_lock);
++ repeat:
++	next = this_parent->d_subdirs.next;
++ resume:
++	if (this_parent->d_sb == sb
++	    && !IS_ROOT(this_parent)
++	    && atomic_read(&this_parent->d_count)
++	    && this_parent->d_inode
++	    && (!test || test(this_parent, arg))) {
++		err = au_dpages_append(dpages, this_parent, GFP_ATOMIC);
++		if (unlikely(err))
++			goto out;
++	}
++
++	while (next != &this_parent->d_subdirs) {
++		struct list_head *tmp = next;
++		struct dentry *dentry = list_entry(tmp, struct dentry,
++						   d_u.d_child);
++		next = tmp->next;
++		if (/*d_unhashed(dentry) || */!dentry->d_inode)
++			continue;
++		if (!list_empty(&dentry->d_subdirs)) {
++			this_parent = dentry;
++			goto repeat;
++		}
++		if (dentry->d_sb == sb
++		    && atomic_read(&dentry->d_count)
++		    && (!test || test(dentry, arg))) {
++			err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
++			if (unlikely(err))
++				goto out;
++		}
++	}
++
++	if (this_parent != root) {
++		next = this_parent->d_u.d_child.next;
++		this_parent = this_parent->d_parent; /* dcache_lock is locked */
++		goto resume;
++	}
++ out:
++	spin_unlock(&dcache_lock);
++	return err;
++}
++
++int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
++		       int do_include, au_dpages_test test, void *arg)
++{
++	int err;
++
++	err = 0;
++	spin_lock(&dcache_lock);
++	if (do_include && (!test || test(dentry, arg))) {
++		err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
++		if (unlikely(err))
++			goto out;
++	}
++	while (!IS_ROOT(dentry)) {
++		dentry = dentry->d_parent; /* dcache_lock is locked */
++		if (!test || test(dentry, arg)) {
++			err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
++			if (unlikely(err))
++				break;
++		}
++	}
++
++ out:
++	spin_unlock(&dcache_lock);
++
++	return err;
++}
++
++struct dentry *au_test_subdir(struct dentry *d1, struct dentry *d2)
++{
++	struct dentry *trap, **dentries;
++	int err, i, j;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++
++	trap = ERR_PTR(-ENOMEM);
++	err = au_dpages_init(&dpages, GFP_NOFS);
++	if (unlikely(err))
++		goto out;
++	err = au_dcsub_pages_rev(&dpages, d1, /*do_include*/1, NULL, NULL);
++	if (unlikely(err))
++		goto out_dpages;
++
++	trap = d1;
++	for (i = 0; !err && i < dpages.ndpage; i++) {
++		dpage = dpages.dpages + i;
++		dentries = dpage->dentries;
++		for (j = 0; !err && j < dpage->ndentry; j++) {
++			struct dentry *d;
++
++			d = dentries[j];
++			err = (d == d2);
++			if (!err)
++				trap = d;
++		}
++	}
++	if (!err)
++		trap = NULL;
++
++ out_dpages:
++	au_dpages_free(&dpages);
++ out:
++	return trap;
++}
+diff -uNr test/fs/aufs/dcsub.h aufs2-standalone/fs/aufs/dcsub.h
+--- test/fs/aufs/dcsub.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/dcsub.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,43 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * sub-routines for dentry cache
++ */
++
++#ifndef __AUFS_DCSUB_H__
++#define __AUFS_DCSUB_H__
++
++#ifdef __KERNEL__
++
++#include <linux/dcache.h>
++
++struct au_dpage {
++	int ndentry;
++	struct dentry **dentries;
++};
++
++struct au_dcsub_pages {
++	int ndpage;
++	struct au_dpage *dpages;
++};
++
++/* ---------------------------------------------------------------------- */
++
++int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp);
++void au_dpages_free(struct au_dcsub_pages *dpages);
++typedef int (*au_dpages_test)(struct dentry *dentry, void *arg);
++int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
++		   au_dpages_test test, void *arg);
++int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
++		       int do_include, au_dpages_test test, void *arg);
++struct dentry *au_test_subdir(struct dentry *d1, struct dentry *d2);
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_DCSUB_H__ */
+diff -uNr test/fs/aufs/debug.c aufs2-standalone/fs/aufs/debug.c
+--- test/fs/aufs/debug.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/debug.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,406 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * debug print functions
++ */
++
++#include "aufs.h"
++
++atomic_t au_cond = ATOMIC_INIT(0);
++
++char *au_plevel = KERN_DEBUG;
++#define dpri(fmt, arg...) do { \
++	if (au_debug_test()) \
++		printk("%s" fmt, au_plevel, ##arg); \
++} while (0)
++
++/* ---------------------------------------------------------------------- */
++
++void au_dpri_whlist(struct au_nhash *whlist)
++{
++	int i;
++	struct hlist_head *head;
++	struct au_vdir_wh *tpos;
++	struct hlist_node *pos;
++
++	for (i = 0; i < AuSize_NHASH; i++) {
++		head = whlist->heads + i;
++		hlist_for_each_entry(tpos, pos, head, wh_hash)
++			dpri("b%d, %.*s, %d\n",
++			     tpos->wh_bindex,
++			     tpos->wh_str.len, tpos->wh_str.name,
++			     tpos->wh_str.len);
++	}
++}
++
++void au_dpri_vdir(struct au_vdir *vdir)
++{
++	int i;
++	union au_vdir_deblk_p p;
++	unsigned char *o;
++
++	if (!vdir || IS_ERR(vdir)) {
++		dpri("err %ld\n", PTR_ERR(vdir));
++		return;
++	}
++
++	dpri("nblk %d, deblk %p, last{%d, %p}, ver %lu\n",
++	     vdir->vd_nblk, vdir->vd_deblk,
++	     vdir->vd_last.i, vdir->vd_last.p.p, vdir->vd_version);
++	for (i = 0; i < vdir->vd_nblk; i++) {
++		p.deblk = vdir->vd_deblk[i];
++		o = p.p;
++		dpri("[%d]: %p\n", i, o);
++	}
++}
++
++static int do_pri_inode(aufs_bindex_t bindex, struct inode *inode,
++			struct dentry *wh)
++{
++	char *n = NULL;
++	int l = 0;
++
++	if (!inode || IS_ERR(inode)) {
++		dpri("i%d: err %ld\n", bindex, PTR_ERR(inode));
++		return -1;
++	}
++
++	/* the type of i_blocks depends upon CONFIG_LSF */
++	BUILD_BUG_ON(sizeof(inode->i_blocks) != sizeof(unsigned long)
++		     && sizeof(inode->i_blocks) != sizeof(u64));
++	if (wh) {
++		n = (void *)wh->d_name.name;
++		l = wh->d_name.len;
++	}
++
++	dpri("i%d: i%lu, %s, cnt %d, nl %u, 0%o, sz %llu, blk %llu,"
++	     " ct %lld, np %lu, st 0x%lx, f 0x%x, g %x%s%.*s\n",
++	     bindex,
++	     inode->i_ino, inode->i_sb ? au_sbtype(inode->i_sb) : "??",
++	     atomic_read(&inode->i_count), inode->i_nlink, inode->i_mode,
++	     i_size_read(inode), (unsigned long long)inode->i_blocks,
++	     (long long)timespec_to_ns(&inode->i_ctime) & 0x0ffff,
++	     inode->i_mapping ? inode->i_mapping->nrpages : 0,
++	     inode->i_state, inode->i_flags, inode->i_generation,
++	     l ? ", wh " : "", l, n);
++	return 0;
++}
++
++void au_dpri_inode(struct inode *inode)
++{
++	struct au_iinfo *iinfo;
++	aufs_bindex_t bindex;
++	int err;
++
++	err = do_pri_inode(-1, inode, NULL);
++	if (err || !au_test_aufs(inode->i_sb))
++		return;
++
++	iinfo = au_ii(inode);
++	if (!iinfo)
++		return;
++	dpri("i-1: bstart %d, bend %d, gen %d\n",
++	     iinfo->ii_bstart, iinfo->ii_bend, au_iigen(inode));
++	if (iinfo->ii_bstart < 0)
++		return;
++	for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend; bindex++)
++		do_pri_inode(bindex, iinfo->ii_hinode[0 + bindex].hi_inode,
++			     iinfo->ii_hinode[0 + bindex].hi_whdentry);
++}
++
++static int do_pri_dentry(aufs_bindex_t bindex, struct dentry *dentry)
++{
++	struct dentry *wh = NULL;
++
++	if (!dentry || IS_ERR(dentry)) {
++		dpri("d%d: err %ld\n", bindex, PTR_ERR(dentry));
++		return -1;
++	}
++	/* do not call dget_parent() here */
++	dpri("d%d: %.*s?/%.*s, %s, cnt %d, flags 0x%x\n",
++	     bindex,
++	     AuDLNPair(dentry->d_parent), AuDLNPair(dentry),
++	     dentry->d_sb ? au_sbtype(dentry->d_sb) : "??",
++	     atomic_read(&dentry->d_count), dentry->d_flags);
++	if (bindex >= 0 && dentry->d_inode && au_test_aufs(dentry->d_sb)) {
++		struct au_iinfo *iinfo = au_ii(dentry->d_inode);
++		if (iinfo)
++			wh = iinfo->ii_hinode[0 + bindex].hi_whdentry;
++	}
++	do_pri_inode(bindex, dentry->d_inode, wh);
++	return 0;
++}
++
++void au_dpri_dentry(struct dentry *dentry)
++{
++	struct au_dinfo *dinfo;
++	aufs_bindex_t bindex;
++	int err;
++
++	err = do_pri_dentry(-1, dentry);
++	if (err || !au_test_aufs(dentry->d_sb))
++		return;
++
++	dinfo = au_di(dentry);
++	if (!dinfo)
++		return;
++	dpri("d-1: bstart %d, bend %d, bwh %d, bdiropq %d, gen %d\n",
++	     dinfo->di_bstart, dinfo->di_bend,
++	     dinfo->di_bwh, dinfo->di_bdiropq, au_digen(dentry));
++	if (dinfo->di_bstart < 0)
++		return;
++	for (bindex = dinfo->di_bstart; bindex <= dinfo->di_bend; bindex++)
++		do_pri_dentry(bindex, dinfo->di_hdentry[0 + bindex].hd_dentry);
++}
++
++static int do_pri_file(aufs_bindex_t bindex, struct file *file)
++{
++	char a[32];
++
++	if (!file || IS_ERR(file)) {
++		dpri("f%d: err %ld\n", bindex, PTR_ERR(file));
++		return -1;
++	}
++	a[0] = 0;
++	if (bindex < 0
++	    && file->f_dentry
++	    && au_test_aufs(file->f_dentry->d_sb)
++	    && au_fi(file))
++		snprintf(a, sizeof(a), ", mmapped %d", au_test_mmapped(file));
++	dpri("f%d: mode 0x%x, flags 0%o, cnt %ld, pos %llu%s\n",
++	     bindex, file->f_mode, file->f_flags, (long)file_count(file),
++	     file->f_pos, a);
++	if (file->f_dentry)
++		do_pri_dentry(bindex, file->f_dentry);
++	return 0;
++}
++
++void au_dpri_file(struct file *file)
++{
++	struct au_finfo *finfo;
++	aufs_bindex_t bindex;
++	int err;
++
++	err = do_pri_file(-1, file);
++	if (err || !file->f_dentry || !au_test_aufs(file->f_dentry->d_sb))
++		return;
++
++	finfo = au_fi(file);
++	if (!finfo)
++		return;
++	if (finfo->fi_bstart < 0)
++		return;
++	for (bindex = finfo->fi_bstart; bindex <= finfo->fi_bend; bindex++) {
++		struct au_hfile *hf;
++
++		hf = finfo->fi_hfile + bindex;
++		do_pri_file(bindex, hf ? hf->hf_file : NULL);
++	}
++}
++
++static int do_pri_br(aufs_bindex_t bindex, struct au_branch *br)
++{
++	struct vfsmount *mnt;
++	struct super_block *sb;
++
++	if (!br || IS_ERR(br)
++	    || !(mnt = br->br_mnt) || IS_ERR(mnt)
++	    || !(sb = mnt->mnt_sb) || IS_ERR(sb)) {
++		dpri("s%d: err %ld\n", bindex, PTR_ERR(br));
++		return -1;
++	}
++
++	dpri("s%d: {perm 0x%x, cnt %d, wbr %p}, "
++	     "%s, dev 0x%02x%02x, flags 0x%lx, cnt(BIAS) %d, active %d, "
++	     "xino %d\n",
++	     bindex, br->br_perm, atomic_read(&br->br_count), br->br_wbr,
++	     au_sbtype(sb), MAJOR(sb->s_dev), MINOR(sb->s_dev),
++	     sb->s_flags, sb->s_count - S_BIAS,
++	     atomic_read(&sb->s_active), !!br->br_xino.xi_file);
++	return 0;
++}
++
++void au_dpri_sb(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++	aufs_bindex_t bindex;
++	int err;
++	/* to reuduce stack size */
++	struct {
++		struct vfsmount mnt;
++		struct au_branch fake;
++	} *a;
++
++	/* this function can be called from magic sysrq */
++	a = kzalloc(sizeof(*a), GFP_ATOMIC);
++	if (unlikely(!a)) {
++		dpri("no memory\n");
++		return;
++	}
++
++	a->mnt.mnt_sb = sb;
++	a->fake.br_perm = 0;
++	a->fake.br_mnt = &a->mnt;
++	a->fake.br_xino.xi_file = NULL;
++	atomic_set(&a->fake.br_count, 0);
++	smp_mb(); /* atomic_set */
++	err = do_pri_br(-1, &a->fake);
++	kfree(a);
++	dpri("dev 0x%x\n", sb->s_dev);
++	if (err || !au_test_aufs(sb))
++		return;
++
++	sbinfo = au_sbi(sb);
++	if (!sbinfo)
++		return;
++	dpri("nw %d, gen %u, kobj %d\n",
++	     atomic_read(&sbinfo->si_nowait.nw_len), sbinfo->si_generation,
++	     atomic_read(&sbinfo->si_kobj.kref.refcount));
++	for (bindex = 0; bindex <= sbinfo->si_bend; bindex++)
++		do_pri_br(bindex, sbinfo->si_branch[0 + bindex]);
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_dbg_sleep_jiffy(int jiffy)
++{
++	while (jiffy)
++		jiffy = schedule_timeout_uninterruptible(jiffy);
++}
++
++void au_dbg_iattr(struct iattr *ia)
++{
++#define AuBit(name)	if (ia->ia_valid & ATTR_ ## name) \
++				dpri(#name "\n")
++	AuBit(MODE);
++	AuBit(UID);
++	AuBit(GID);
++	AuBit(SIZE);
++	AuBit(ATIME);
++	AuBit(MTIME);
++	AuBit(CTIME);
++	AuBit(ATIME_SET);
++	AuBit(MTIME_SET);
++	AuBit(FORCE);
++	AuBit(ATTR_FLAG);
++	AuBit(KILL_SUID);
++	AuBit(KILL_SGID);
++	AuBit(FILE);
++	AuBit(KILL_PRIV);
++	AuBit(OPEN);
++	AuBit(TIMES_SET);
++#undef	AuBit
++	dpri("ia_file %p\n", ia->ia_file);
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_dbg_verify_dir_parent(struct dentry *dentry, unsigned int sigen)
++{
++	struct dentry *parent;
++
++	parent = dget_parent(dentry);
++	AuDebugOn(!S_ISDIR(dentry->d_inode->i_mode)
++		  || IS_ROOT(dentry)
++		  || au_digen(parent) != sigen);
++	dput(parent);
++}
++
++void au_dbg_verify_nondir_parent(struct dentry *dentry, unsigned int sigen)
++{
++	struct dentry *parent;
++
++	parent = dget_parent(dentry);
++	AuDebugOn(S_ISDIR(dentry->d_inode->i_mode)
++		  || au_digen(parent) != sigen);
++	dput(parent);
++}
++
++void au_dbg_verify_gen(struct dentry *parent, unsigned int sigen)
++{
++	int err, i, j;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry **dentries;
++
++	err = au_dpages_init(&dpages, GFP_NOFS);
++	AuDebugOn(err);
++	err = au_dcsub_pages_rev(&dpages, parent, /*do_include*/1, NULL, NULL);
++	AuDebugOn(err);
++	for (i = dpages.ndpage - 1; !err && i >= 0; i--) {
++		dpage = dpages.dpages + i;
++		dentries = dpage->dentries;
++		for (j = dpage->ndentry - 1; !err && j >= 0; j--)
++			AuDebugOn(au_digen(dentries[j]) != sigen);
++	}
++	au_dpages_free(&dpages);
++}
++
++void au_dbg_verify_hf(struct au_finfo *finfo)
++{
++	struct au_hfile *hf;
++	aufs_bindex_t bend, bindex;
++
++	if (finfo->fi_bstart >= 0) {
++		bend = finfo->fi_bend;
++		for (bindex = finfo->fi_bstart; bindex <= bend; bindex++) {
++			hf = finfo->fi_hfile + bindex;
++			AuDebugOn(hf->hf_file || hf->hf_br);
++		}
++	}
++}
++
++void au_dbg_verify_kthread(void)
++{
++	if (au_test_wkq(current)) {
++		au_dbg_blocked();
++		BUG();
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_debug_sbinfo_init(struct au_sbinfo *sbinfo __maybe_unused)
++{
++#ifdef AuForceNoPlink
++	au_opt_clr(sbinfo->si_mntflags, PLINK);
++#endif
++#ifdef AuForceNoXino
++	au_opt_clr(sbinfo->si_mntflags, XINO);
++#endif
++#ifdef AuForceNoRefrof
++	au_opt_clr(sbinfo->si_mntflags, REFROF);
++#endif
++#ifdef AuForceHinotify
++	au_opt_set_udba(sbinfo->si_mntflags, UDBA_HINOTIFY);
++#endif
++}
++
++int __init au_debug_init(void)
++{
++	aufs_bindex_t bindex;
++	struct au_vdir_destr destr;
++
++	bindex = -1;
++	AuDebugOn(bindex >= 0);
++
++	destr.len = -1;
++	AuDebugOn(destr.len < NAME_MAX);
++
++#ifdef CONFIG_4KSTACKS
++	AuWarn("CONFIG_4KSTACKS is defined.\n");
++#endif
++
++#ifdef AuForceNoBrs
++	sysaufs_brs = 0;
++#endif
++
++	return 0;
++}
+diff -uNr test/fs/aufs/debug.h aufs2-standalone/fs/aufs/debug.h
+--- test/fs/aufs/debug.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/debug.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,245 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * debug print functions
++ */
++
++#ifndef __AUFS_DEBUG_H__
++#define __AUFS_DEBUG_H__
++
++#ifdef __KERNEL__
++
++#include <linux/delay.h>
++#include <linux/fs.h>
++#include <linux/kd.h>
++#include <linux/vt_kern.h>
++#include <linux/sysrq.h>
++#include <linux/aufs_type.h>
++
++#ifdef CONFIG_AUFS_DEBUG
++#define AuDebugOn(a)		BUG_ON(a)
++extern atomic_t au_cond;
++static inline void au_debug(int n)
++{
++	atomic_set(&au_cond, n);
++	smp_mb();
++}
++
++static inline int au_debug_test(void)
++{
++	int ret;
++
++	ret = atomic_read(&au_cond);
++	smp_mb();
++	return ret;
++}
++#else
++#define AuDebugOn(a)		do {} while (0)
++#define au_debug()		do {} while (0)
++static inline int au_debug_test(void)
++{
++	return 0;
++}
++#endif /* CONFIG_AUFS_DEBUG */
++
++/* ---------------------------------------------------------------------- */
++
++/* debug print */
++
++#define AuDpri(lvl, fmt, arg...) \
++	printk(lvl AUFS_NAME " %s:%d:%s[%d]: " fmt, \
++	       __func__, __LINE__, current->comm, current->pid, ##arg)
++#define AuDbg(fmt, arg...) do { \
++	if (au_debug_test()) \
++		AuDpri(KERN_DEBUG, fmt, ##arg); \
++} while (0)
++#define AuLabel(l) 		AuDbg(#l "\n")
++#define AuInfo(fmt, arg...)	AuDpri(KERN_INFO, fmt, ##arg)
++#define AuWarn(fmt, arg...)	AuDpri(KERN_WARNING, fmt, ##arg)
++#define AuErr(fmt, arg...)	AuDpri(KERN_ERR, fmt, ##arg)
++#define AuIOErr(fmt, arg...)	AuErr("I/O Error, " fmt, ##arg)
++#define AuWarn1(fmt, arg...) do { \
++	static unsigned char _c; \
++	if (!_c++) \
++		AuWarn(fmt, ##arg); \
++} while (0)
++
++#define AuErr1(fmt, arg...) do { \
++	static unsigned char _c; \
++	if (!_c++) \
++		AuErr(fmt, ##arg); \
++} while (0)
++
++#define AuIOErr1(fmt, arg...) do { \
++	static unsigned char _c; \
++	if (!_c++) \
++		AuIOErr(fmt, ##arg); \
++} while (0)
++
++#define AuUnsupportMsg	"This operation is not supported." \
++			" Please report this application to aufs-users ML."
++#define AuUnsupport(fmt, args...) do { \
++	AuErr(AuUnsupportMsg "\n" fmt, ##args); \
++	dump_stack(); \
++} while (0)
++
++#define AuTraceErr(e) do { \
++	if (unlikely((e) < 0)) \
++		AuDbg("err %d\n", (int)(e)); \
++} while (0)
++
++#define AuTraceErrPtr(p) do { \
++	if (IS_ERR(p)) \
++		AuDbg("err %ld\n", PTR_ERR(p)); \
++} while (0)
++
++/* dirty macros for debug print, use with "%.*s" and caution */
++#define AuLNPair(qstr)		(qstr)->len, (qstr)->name
++#define AuDLNPair(d)		AuLNPair(&(d)->d_name)
++
++/* ---------------------------------------------------------------------- */
++
++struct au_sbinfo;
++struct au_finfo;
++#ifdef CONFIG_AUFS_DEBUG
++extern char *au_plevel;
++struct au_nhash;
++void au_dpri_whlist(struct au_nhash *whlist);
++struct au_vdir;
++void au_dpri_vdir(struct au_vdir *vdir);
++void au_dpri_inode(struct inode *inode);
++void au_dpri_dentry(struct dentry *dentry);
++void au_dpri_file(struct file *filp);
++void au_dpri_sb(struct super_block *sb);
++
++void au_dbg_sleep_jiffy(int jiffy);
++void au_dbg_iattr(struct iattr *ia);
++
++void au_dbg_verify_dir_parent(struct dentry *dentry, unsigned int sigen);
++void au_dbg_verify_nondir_parent(struct dentry *dentry, unsigned int sigen);
++void au_dbg_verify_gen(struct dentry *parent, unsigned int sigen);
++void au_dbg_verify_hf(struct au_finfo *finfo);
++void au_dbg_verify_kthread(void);
++
++int __init au_debug_init(void);
++void au_debug_sbinfo_init(struct au_sbinfo *sbinfo);
++#define AuDbgWhlist(w) do { \
++	AuDbg(#w "\n"); \
++	au_dpri_whlist(w); \
++} while (0)
++
++#define AuDbgVdir(v) do { \
++	AuDbg(#v "\n"); \
++	au_dpri_vdir(v); \
++} while (0)
++
++#define AuDbgInode(i) do { \
++	AuDbg(#i "\n"); \
++	au_dpri_inode(i); \
++} while (0)
++
++#define AuDbgDentry(d) do { \
++	AuDbg(#d "\n"); \
++	au_dpri_dentry(d); \
++} while (0)
++
++#define AuDbgFile(f) do { \
++	AuDbg(#f "\n"); \
++	au_dpri_file(f); \
++} while (0)
++
++#define AuDbgSb(sb) do { \
++	AuDbg(#sb "\n"); \
++	au_dpri_sb(sb); \
++} while (0)
++
++#define AuDbgSleep(sec) do { \
++	AuDbg("sleep %d sec\n", sec); \
++	ssleep(sec); \
++} while (0)
++
++#define AuDbgSleepJiffy(jiffy) do { \
++	AuDbg("sleep %d jiffies\n", jiffy); \
++	au_dbg_sleep_jiffy(jiffy); \
++} while (0)
++
++#define AuDbgIAttr(ia) do { \
++	AuDbg("ia_valid 0x%x\n", (ia)->ia_valid); \
++	au_dbg_iattr(ia); \
++} while (0)
++#else
++static inline void au_dbg_verify_dir_parent(struct dentry *dentry,
++					    unsigned int sigen)
++{
++	/* empty */
++}
++static inline void au_dbg_verify_nondir_parent(struct dentry *dentry,
++					   unsigned int sigen)
++{
++	/* empty */
++}
++static inline void au_dbg_verify_gen(struct dentry *parent, unsigned int sigen)
++{
++	/* empty */
++}
++static inline void au_dbg_verify_hf(struct au_finfo *finfo)
++{
++	/* empty */
++}
++static inline void au_dbg_verify_kthread(void)
++{
++	/* empty */
++}
++
++static inline int au_debug_init(void)
++{
++	return 0;
++}
++static inline void au_debug_sbinfo_init(struct au_sbinfo *sbinfo)
++{
++	/* empty */
++}
++#define AuDbgWhlist(w)		do {} while (0)
++#define AuDbgVdir(v)		do {} while (0)
++#define AuDbgInode(i)		do {} while (0)
++#define AuDbgDentry(d)		do {} while (0)
++#define AuDbgFile(f)		do {} while (0)
++#define AuDbgSb(sb)		do {} while (0)
++#define AuDbgSleep(sec)		do {} while (0)
++#define AuDbgSleepJiffy(jiffy)	do {} while (0)
++#define AuDbgIAttr(ia)		do {} while (0)
++#endif /* CONFIG_AUFS_DEBUG */
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_MAGIC_SYSRQ
++int __init au_sysrq_init(void);
++void au_sysrq_fin(void);
++
++#ifdef CONFIG_HW_CONSOLE
++#define au_dbg_blocked() do { \
++	WARN_ON(1); \
++	handle_sysrq('w', vc_cons[fg_console].d->vc_tty); \
++} while (0)
++#else
++#define au_dbg_blocked()	do {} while (0)
++#endif
++
++#else
++static inline int au_sysrq_init(void)
++{
++	return 0;
++}
++#define au_sysrq_fin()		do {} while (0)
++#define au_dbg_blocked()	do {} while (0)
++#endif /* CONFIG_AUFS_MAGIC_SYSRQ */
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_DEBUG_H__ */
+diff -uNr test/fs/aufs/dentry.c aufs2-standalone/fs/aufs/dentry.c
+--- test/fs/aufs/dentry.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/dentry.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,858 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * lookup and dentry operations
++ */
++
++#include "aufs.h"
++
++static void au_h_nd(struct nameidata *h_nd, struct nameidata *nd)
++{
++	if (nd) {
++		*h_nd = *nd;
++
++		/*
++		 * gave up supporting LOOKUP_CREATE/OPEN for lower fs,
++		 * due to whiteout and branch permission.
++		 */
++		h_nd->flags &= ~(/*LOOKUP_PARENT |*/ LOOKUP_OPEN | LOOKUP_CREATE
++				 | LOOKUP_FOLLOW);
++		/* unnecessary? */
++		h_nd->intent.open.file = NULL;
++	} else
++		memset(h_nd, 0, sizeof(*h_nd));
++}
++
++struct au_lkup_one_args {
++	struct dentry **errp;
++	struct qstr *name;
++	struct dentry *h_parent;
++	struct au_branch *br;
++	struct nameidata *nd;
++};
++
++struct dentry *au_lkup_one(struct qstr *name, struct dentry *h_parent,
++			   struct au_branch *br, struct nameidata *nd)
++{
++	struct dentry *h_dentry;
++	int err;
++	struct nameidata h_nd;
++
++	if (au_test_fs_null_nd(h_parent->d_sb))
++		return vfsub_lookup_one_len(name->name, h_parent, name->len);
++
++	au_h_nd(&h_nd, nd);
++	h_nd.path.dentry = h_parent;
++	h_nd.path.mnt = br->br_mnt;
++
++	err = __lookup_one_len(name->name, &h_nd.last, NULL, name->len);
++	h_dentry = ERR_PTR(err);
++	if (!err) {
++		path_get(&h_nd.path);
++		h_dentry = vfsub_lookup_hash(&h_nd);
++		path_put(&h_nd.path);
++	}
++
++	return h_dentry;
++}
++
++static void au_call_lkup_one(void *args)
++{
++	struct au_lkup_one_args *a = args;
++	*a->errp = au_lkup_one(a->name, a->h_parent, a->br, a->nd);
++}
++
++#define AuLkup_ALLOW_NEG	1
++#define au_ftest_lkup(flags, name)	((flags) & AuLkup_##name)
++#define au_fset_lkup(flags, name)	{ (flags) |= AuLkup_##name; }
++#define au_fclr_lkup(flags, name)	{ (flags) &= ~AuLkup_##name; }
++
++struct au_do_lookup_args {
++	unsigned int		flags;
++	mode_t			type;
++	struct nameidata	*nd;
++};
++
++/*
++ * returns positive/negative dentry, NULL or an error.
++ * NULL means whiteout-ed or not-found.
++ */
++static struct dentry*
++au_do_lookup(struct dentry *h_parent, struct dentry *dentry,
++	     aufs_bindex_t bindex, struct qstr *wh_name,
++	     struct au_do_lookup_args *args)
++{
++	struct dentry *h_dentry;
++	struct inode *h_inode, *inode;
++	struct qstr *name;
++	struct au_branch *br;
++	int wh_found, opq;
++	unsigned char wh_able;
++	const unsigned char allow_neg = !!au_ftest_lkup(args->flags, ALLOW_NEG);
++
++	name = &dentry->d_name;
++	wh_found = 0;
++	br = au_sbr(dentry->d_sb, bindex);
++	wh_able = !!au_br_whable(br->br_perm);
++	if (wh_able)
++		wh_found = au_wh_test(h_parent, wh_name, br, /*try_sio*/0);
++	h_dentry = ERR_PTR(wh_found);
++	if (!wh_found)
++		goto real_lookup;
++	if (unlikely(wh_found < 0))
++		goto out;
++
++	/* We found a whiteout */
++	/* au_set_dbend(dentry, bindex); */
++	au_set_dbwh(dentry, bindex);
++	if (!allow_neg)
++		return NULL; /* success */
++
++ real_lookup:
++	h_dentry = au_lkup_one(name, h_parent, br, args->nd);
++	if (IS_ERR(h_dentry))
++		goto out;
++
++	h_inode = h_dentry->d_inode;
++	if (!h_inode) {
++		if (!allow_neg)
++			goto out_neg;
++	} else if (wh_found
++		   || (args->type && args->type != (h_inode->i_mode & S_IFMT)))
++		goto out_neg;
++
++	if (au_dbend(dentry) <= bindex)
++		au_set_dbend(dentry, bindex);
++	if (au_dbstart(dentry) < 0 || bindex < au_dbstart(dentry))
++		au_set_dbstart(dentry, bindex);
++	au_set_h_dptr(dentry, bindex, h_dentry);
++
++	inode = dentry->d_inode;
++	if (!h_inode || !S_ISDIR(h_inode->i_mode) || !wh_able
++	    || (inode && !S_ISDIR(inode->i_mode)))
++		goto out; /* success */
++
++	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++	opq = au_diropq_test(h_dentry, br);
++	mutex_unlock(&h_inode->i_mutex);
++	if (opq > 0)
++		au_set_dbdiropq(dentry, bindex);
++	else if (unlikely(opq < 0)) {
++		au_set_h_dptr(dentry, bindex, NULL);
++		h_dentry = ERR_PTR(opq);
++	}
++	goto out;
++
++ out_neg:
++	dput(h_dentry);
++	h_dentry = NULL;
++ out:
++	return h_dentry;
++}
++
++/*
++ * returns the number of lower positive dentries,
++ * otherwise an error.
++ * can be called at unlinking with @type is zero.
++ */
++int au_lkup_dentry(struct dentry *dentry, aufs_bindex_t bstart, mode_t type,
++		   struct nameidata *nd)
++{
++	int npositive, err;
++	aufs_bindex_t bindex, btail, bdiropq;
++	unsigned char isdir;
++	struct qstr whname;
++	struct au_do_lookup_args args = {
++		.flags	= 0,
++		.type	= type,
++		.nd	= nd
++	};
++	const struct qstr *name = &dentry->d_name;
++	struct dentry *parent;
++	struct inode *inode;
++
++	err = -EPERM;
++	parent = dget_parent(dentry);
++	if (unlikely(!strncmp(name->name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)))
++		goto out;
++
++	err = au_wh_name_alloc(&whname, name);
++	if (unlikely(err))
++		goto out;
++
++	inode = dentry->d_inode;
++	isdir = !!(inode && S_ISDIR(inode->i_mode));
++	if (!type)
++		au_fset_lkup(args.flags, ALLOW_NEG);
++
++	npositive = 0;
++	btail = au_dbtaildir(parent);
++	for (bindex = bstart; bindex <= btail; bindex++) {
++		struct dentry *h_parent, *h_dentry;
++		struct inode *h_inode, *h_dir;
++
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (h_dentry) {
++			if (h_dentry->d_inode)
++				npositive++;
++			if (type != S_IFDIR)
++				break;
++			continue;
++		}
++		h_parent = au_h_dptr(parent, bindex);
++		if (!h_parent)
++			continue;
++		h_dir = h_parent->d_inode;
++		if (!h_dir || !S_ISDIR(h_dir->i_mode))
++			continue;
++
++		mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
++		h_dentry = au_do_lookup(h_parent, dentry, bindex, &whname,
++					&args);
++		mutex_unlock(&h_dir->i_mutex);
++		err = PTR_ERR(h_dentry);
++		if (IS_ERR(h_dentry))
++			goto out_wh;
++		au_fclr_lkup(args.flags, ALLOW_NEG);
++
++		if (au_dbwh(dentry) >= 0)
++			break;
++		if (!h_dentry)
++			continue;
++		h_inode = h_dentry->d_inode;
++		if (!h_inode)
++			continue;
++		npositive++;
++		if (!args.type)
++			args.type = h_inode->i_mode & S_IFMT;
++		if (args.type != S_IFDIR)
++			break;
++		else if (isdir) {
++			/* the type of lower may be different */
++			bdiropq = au_dbdiropq(dentry);
++			if (bdiropq >= 0 && bdiropq <= bindex)
++				break;
++		}
++	}
++
++	if (npositive) {
++		AuLabel(positive);
++		au_update_dbstart(dentry);
++	}
++	err = npositive;
++	if (unlikely(!au_opt_test(au_mntflags(dentry->d_sb), UDBA_NONE)
++		     && au_dbstart(dentry) < 0))
++		/* both of real entry and whiteout found */
++		err = -EIO;
++
++ out_wh:
++	kfree(whname.name);
++ out:
++	dput(parent);
++	return err;
++}
++
++struct dentry *au_sio_lkup_one(struct qstr *name, struct dentry *parent,
++			       struct au_branch *br)
++{
++	struct dentry *dentry;
++	int wkq_err;
++
++	if (!au_test_h_perm_sio(parent->d_inode, MAY_EXEC))
++		dentry = au_lkup_one(name, parent, br, /*nd*/NULL);
++	else {
++		struct au_lkup_one_args args = {
++			.errp		= &dentry,
++			.name		= name,
++			.h_parent	= parent,
++			.br		= br,
++			.nd		= NULL
++		};
++
++		wkq_err = au_wkq_wait(au_call_lkup_one, &args);
++		if (unlikely(wkq_err))
++			dentry = ERR_PTR(wkq_err);
++	}
++
++	return dentry;
++}
++
++/*
++ * lookup @dentry on @bindex which should be negative.
++ */
++int au_lkup_neg(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	int err;
++	struct dentry *parent, *h_parent, *h_dentry;
++	struct qstr *name;
++
++	name = &dentry->d_name;
++	parent = dget_parent(dentry);
++	h_parent = au_h_dptr(parent, bindex);
++	h_dentry = au_sio_lkup_one(name, h_parent,
++				   au_sbr(dentry->d_sb, bindex));
++	err = PTR_ERR(h_dentry);
++	if (IS_ERR(h_dentry))
++		goto out;
++	if (unlikely(h_dentry->d_inode)) {
++		err = -EIO;
++		AuIOErr("b%d %.*s should be negative.\n",
++			bindex, AuDLNPair(h_dentry));
++		dput(h_dentry);
++		goto out;
++	}
++
++	if (bindex < au_dbstart(dentry))
++		au_set_dbstart(dentry, bindex);
++	if (au_dbend(dentry) < bindex)
++		au_set_dbend(dentry, bindex);
++	au_set_h_dptr(dentry, bindex, h_dentry);
++	err = 0;
++
++ out:
++	dput(parent);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* subset of struct inode */
++struct au_iattr {
++	unsigned long		i_ino;
++	/* unsigned int		i_nlink; */
++	uid_t			i_uid;
++	gid_t			i_gid;
++	u64			i_version;
++/*
++	loff_t			i_size;
++	blkcnt_t		i_blocks;
++*/
++	umode_t			i_mode;
++};
++
++static void au_iattr_save(struct au_iattr *ia, struct inode *h_inode)
++{
++	ia->i_ino = h_inode->i_ino;
++	/* ia->i_nlink = h_inode->i_nlink; */
++	ia->i_uid = h_inode->i_uid;
++	ia->i_gid = h_inode->i_gid;
++	ia->i_version = h_inode->i_version;
++/*
++	ia->i_size = h_inode->i_size;
++	ia->i_blocks = h_inode->i_blocks;
++*/
++	ia->i_mode = (h_inode->i_mode & S_IFMT);
++}
++
++static int au_iattr_test(struct au_iattr *ia, struct inode *h_inode)
++{
++	return ia->i_ino != h_inode->i_ino
++		/* || ia->i_nlink != h_inode->i_nlink */
++		|| ia->i_uid != h_inode->i_uid
++		|| ia->i_gid != h_inode->i_gid
++		|| ia->i_version != h_inode->i_version
++/*
++		|| ia->i_size != h_inode->i_size
++		|| ia->i_blocks != h_inode->i_blocks
++*/
++		|| ia->i_mode != (h_inode->i_mode & S_IFMT);
++}
++
++static int au_h_verify_dentry(struct dentry *h_dentry, struct dentry *h_parent,
++			      struct au_branch *br)
++{
++	int err;
++	struct au_iattr ia;
++	struct dentry *h_d;
++	struct inode *h_inode;
++	struct super_block *h_sb;
++
++	err = 0;
++	memset(&ia, -1, sizeof(ia));
++	h_sb = h_dentry->d_sb;
++	h_inode = h_dentry->d_inode;
++	if (h_inode)
++		au_iattr_save(&ia, h_dentry->d_inode);
++	else if (au_test_nfs(h_sb) || au_test_fuse(h_sb))
++		/* nfs d_revalidate may return 0 for negative dentry */
++		/* fuse d_revalidate always return 0 for negative dentry */
++		goto out;
++
++	/* main purpose is namei.c:cached_lookup() and d_revalidate */
++	h_d = au_lkup_one(&h_dentry->d_name, h_parent, br, /*nd*/NULL);
++	err = PTR_ERR(h_d);
++	if (IS_ERR(h_d))
++		goto out;
++
++	err = 0;
++	if (unlikely(h_d != h_dentry
++		     || h_d->d_inode != h_inode
++		     || (h_inode && au_iattr_test(&ia, h_inode))))
++		err = -EBUSY;
++	dput(h_d);
++
++ out:
++	AuTraceErr(err);
++	return err;
++}
++
++int au_h_verify(struct dentry *h_dentry, unsigned int udba, struct inode *h_dir,
++		struct dentry *h_parent, struct au_branch *br)
++{
++	int err;
++
++	err = 0;
++	if (udba == AuOpt_UDBA_REVAL) {
++		IMustLock(h_dir);
++		err = (h_dentry->d_parent->d_inode != h_dir);
++	} else if (udba == AuOpt_UDBA_HINOTIFY)
++		err = au_h_verify_dentry(h_dentry, h_parent, br);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void au_do_refresh_hdentry(struct au_hdentry *p, struct au_dinfo *dinfo,
++				  struct dentry *parent)
++{
++	struct dentry *h_d, *h_dp;
++	struct au_hdentry tmp, *q;
++	struct super_block *sb;
++	aufs_bindex_t new_bindex, bindex, bend, bwh, bdiropq;
++
++	bend = dinfo->di_bend;
++	bwh = dinfo->di_bwh;
++	bdiropq = dinfo->di_bdiropq;
++	for (bindex = dinfo->di_bstart; bindex <= bend; bindex++, p++) {
++		h_d = p->hd_dentry;
++		if (!h_d)
++			continue;
++
++		h_dp = dget_parent(h_d);
++		if (h_dp == au_h_dptr(parent, bindex)) {
++			dput(h_dp);
++			continue;
++		}
++
++		new_bindex = au_find_dbindex(parent, h_dp);
++		dput(h_dp);
++		if (dinfo->di_bwh == bindex)
++			bwh = new_bindex;
++		if (dinfo->di_bdiropq == bindex)
++			bdiropq = new_bindex;
++		if (new_bindex < 0) {
++			au_hdput(p);
++			p->hd_dentry = NULL;
++			continue;
++		}
++
++		/* swap two lower dentries, and loop again */
++		q = dinfo->di_hdentry + new_bindex;
++		tmp = *q;
++		*q = *p;
++		*p = tmp;
++		if (tmp.hd_dentry) {
++			bindex--;
++			p--;
++		}
++	}
++
++	sb = parent->d_sb;
++	dinfo->di_bwh = -1;
++	if (bwh >= 0 && bwh <= au_sbend(sb) && au_sbr_whable(sb, bwh))
++		dinfo->di_bwh = bwh;
++
++	dinfo->di_bdiropq = -1;
++	if (bdiropq >= 0
++	    && bdiropq <= au_sbend(sb)
++	    && au_sbr_whable(sb, bdiropq))
++		dinfo->di_bdiropq = bdiropq;
++
++	bend = au_dbend(parent);
++	p = dinfo->di_hdentry;
++	for (bindex = 0; bindex <= bend; bindex++, p++)
++		if (p->hd_dentry) {
++			dinfo->di_bstart = bindex;
++			break;
++		}
++
++	p = dinfo->di_hdentry + bend;
++	for (bindex = bend; bindex >= 0; bindex--, p--)
++		if (p->hd_dentry) {
++			dinfo->di_bend = bindex;
++			break;
++		}
++}
++
++/*
++ * returns the number of found lower positive dentries,
++ * otherwise an error.
++ */
++int au_refresh_hdentry(struct dentry *dentry, mode_t type)
++{
++	int npositive, err;
++	unsigned int sigen;
++	aufs_bindex_t bstart;
++	struct au_dinfo *dinfo;
++	struct super_block *sb;
++	struct dentry *parent;
++
++	sb = dentry->d_sb;
++	AuDebugOn(IS_ROOT(dentry));
++	sigen = au_sigen(sb);
++	parent = dget_parent(dentry);
++	AuDebugOn(au_digen(parent) != sigen
++		  || au_iigen(parent->d_inode) != sigen);
++
++	dinfo = au_di(dentry);
++	err = au_di_realloc(dinfo, au_sbend(sb) + 1);
++	npositive = err;
++	if (unlikely(err))
++		goto out;
++	au_do_refresh_hdentry(dinfo->di_hdentry + dinfo->di_bstart, dinfo,
++			      parent);
++
++	npositive = 0;
++	bstart = au_dbstart(parent);
++	if (type != S_IFDIR && dinfo->di_bstart == bstart)
++		goto out_dgen; /* success */
++
++	npositive = au_lkup_dentry(dentry, bstart, type, /*nd*/NULL);
++	if (npositive < 0)
++		goto out;
++	if (dinfo->di_bwh >= 0 && dinfo->di_bwh <= dinfo->di_bstart)
++		d_drop(dentry);
++
++ out_dgen:
++	au_update_digen(dentry);
++ out:
++	dput(parent);
++	AuTraceErr(npositive);
++	return npositive;
++}
++
++static noinline_for_stack
++int au_do_h_d_reval(struct dentry *h_dentry, struct nameidata *nd,
++		    struct dentry *dentry, aufs_bindex_t bindex)
++{
++	int err, valid;
++	int (*reval)(struct dentry *, struct nameidata *);
++
++	err = 0;
++	reval = NULL;
++	if (h_dentry->d_op)
++		reval = h_dentry->d_op->d_revalidate;
++	if (!reval)
++		goto out;
++
++	AuDbg("b%d\n", bindex);
++	if (au_test_fs_null_nd(h_dentry->d_sb))
++		/* it may return tri-state */
++		valid = reval(h_dentry, NULL);
++	else {
++		struct nameidata h_nd;
++		int locked;
++		struct dentry *parent;
++
++		au_h_nd(&h_nd, nd);
++		parent = nd->path.dentry;
++		locked = (nd && nd->path.dentry != dentry);
++		if (locked)
++			di_read_lock_parent(parent, AuLock_IR);
++		BUG_ON(bindex > au_dbend(parent));
++		h_nd.path.dentry = au_h_dptr(parent, bindex);
++		BUG_ON(!h_nd.path.dentry);
++		h_nd.path.mnt = au_sbr(parent->d_sb, bindex)->br_mnt;
++		path_get(&h_nd.path);
++		valid = reval(h_dentry, &h_nd);
++		path_put(&h_nd.path);
++		if (locked)
++			di_read_unlock(parent, AuLock_IR);
++	}
++
++	if (unlikely(valid < 0))
++		err = valid;
++	else if (!valid)
++		err = -EINVAL;
++
++ out:
++	AuTraceErr(err);
++	return err;
++}
++
++/* todo: remove this */
++static int h_d_revalidate(struct dentry *dentry, struct inode *inode,
++			  struct nameidata *nd, int do_udba)
++{
++	int err;
++	umode_t mode, h_mode;
++	aufs_bindex_t bindex, btail, bstart, ibs, ibe;
++	unsigned char plus, unhashed, is_root, h_plus;
++	struct inode *first, *h_inode, *h_cached_inode;
++	struct dentry *h_dentry;
++	struct qstr *name, *h_name;
++
++	err = 0;
++	plus = 0;
++	mode = 0;
++	first = NULL;
++	ibs = -1;
++	ibe = -1;
++	unhashed = !!d_unhashed(dentry);
++	is_root = !!IS_ROOT(dentry);
++	name = &dentry->d_name;
++
++	/*
++	 * Theoretically, REVAL test should be unnecessary in case of INOTIFY.
++	 * But inotify doesn't fire some necessary events,
++	 *	IN_ATTRIB for atime/nlink/pageio
++	 *	IN_DELETE for NFS dentry
++	 * Let's do REVAL test too.
++	 */
++	if (do_udba && inode) {
++		mode = (inode->i_mode & S_IFMT);
++		plus = (inode->i_nlink > 0);
++		first = au_h_iptr(inode, au_ibstart(inode));
++		ibs = au_ibstart(inode);
++		ibe = au_ibend(inode);
++	}
++
++	bstart = au_dbstart(dentry);
++	btail = bstart;
++	if (inode && S_ISDIR(inode->i_mode))
++		btail = au_dbtaildir(dentry);
++	for (bindex = bstart; bindex <= btail; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++
++		AuDbg("b%d, %.*s\n", bindex, AuDLNPair(h_dentry));
++		h_name = &h_dentry->d_name;
++		if (unlikely(do_udba
++			     && !is_root
++			     && (unhashed != !!d_unhashed(h_dentry)
++				 || name->len != h_name->len
++				 || memcmp(name->name, h_name->name, name->len))
++			    )) {
++			AuDbg("unhash 0x%x 0x%x, %.*s %.*s\n",
++				  unhashed, d_unhashed(h_dentry),
++				  AuDLNPair(dentry), AuDLNPair(h_dentry));
++			goto err;
++		}
++
++		err = au_do_h_d_reval(h_dentry, nd, dentry, bindex);
++		if (unlikely(err))
++			/* do not goto err, to keep the errno */
++			break;
++
++		/* todo: plink too? */
++		if (!do_udba)
++			continue;
++
++		/* UDBA tests */
++		h_inode = h_dentry->d_inode;
++		if (unlikely(!!inode != !!h_inode))
++			goto err;
++
++		h_plus = plus;
++		h_mode = mode;
++		h_cached_inode = h_inode;
++		if (h_inode) {
++			h_mode = (h_inode->i_mode & S_IFMT);
++			h_plus = (h_inode->i_nlink > 0);
++		}
++		if (inode && ibs <= bindex && bindex <= ibe)
++			h_cached_inode = au_h_iptr(inode, bindex);
++
++		if (unlikely(plus != h_plus
++			     || mode != h_mode
++			     || h_cached_inode != h_inode))
++			goto err;
++		continue;
++
++	err:
++		err = -EINVAL;
++		break;
++	}
++
++	return err;
++}
++
++static int simple_reval_dpath(struct dentry *dentry, unsigned int sigen)
++{
++	int err;
++	struct dentry *parent;
++	struct inode *inode;
++
++	inode = dentry->d_inode;
++	if (au_digen(dentry) == sigen && au_iigen(inode) == sigen)
++		return 0;
++
++	parent = dget_parent(dentry);
++	di_read_lock_parent(parent, AuLock_IR);
++	AuDebugOn(au_digen(parent) != sigen
++		  || au_iigen(parent->d_inode) != sigen);
++	au_dbg_verify_gen(parent, sigen);
++
++	/* returns a number of positive dentries */
++	err = au_refresh_hdentry(dentry, inode->i_mode & S_IFMT);
++	if (err >= 0)
++		err = au_refresh_hinode(inode, dentry);
++
++	di_read_unlock(parent, AuLock_IR);
++	dput(parent);
++	return err;
++}
++
++int au_reval_dpath(struct dentry *dentry, unsigned int sigen)
++{
++	int err;
++	struct dentry *d, *parent;
++	struct inode *inode;
++
++	if (!au_ftest_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIRS))
++		return simple_reval_dpath(dentry, sigen);
++
++	/* slow loop, keep it simple and stupid */
++	/* cf: au_cpup_dirs() */
++	err = 0;
++	parent = NULL;
++	while (au_digen(dentry) != sigen
++	       || au_iigen(dentry->d_inode) != sigen) {
++		d = dentry;
++		while (1) {
++			dput(parent);
++			parent = dget_parent(d);
++			if (au_digen(parent) == sigen
++			    && au_iigen(parent->d_inode) == sigen)
++				break;
++			d = parent;
++		}
++
++		inode = d->d_inode;
++		if (d != dentry)
++			di_write_lock_child(d);
++
++		/* someone might update our dentry while we were sleeping */
++		if (au_digen(d) != sigen || au_iigen(d->d_inode) != sigen) {
++			di_read_lock_parent(parent, AuLock_IR);
++			/* returns a number of positive dentries */
++			err = au_refresh_hdentry(d, inode->i_mode & S_IFMT);
++			if (err >= 0)
++				err = au_refresh_hinode(inode, d);
++			di_read_unlock(parent, AuLock_IR);
++		}
++
++		if (d != dentry)
++			di_write_unlock(d);
++		dput(parent);
++		if (unlikely(err))
++			break;
++	}
++
++	return err;
++}
++
++/*
++ * if valid returns 1, otherwise 0.
++ */
++static int aufs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
++{
++	int valid, err;
++	unsigned int sigen;
++	unsigned char do_udba;
++	struct super_block *sb;
++	struct inode *inode;
++
++	err = -EINVAL;
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	aufs_read_lock(dentry, AuLock_FLUSH | AuLock_DW);
++	sigen = au_sigen(sb);
++	if (au_digen(dentry) != sigen) {
++		AuDebugOn(IS_ROOT(dentry));
++		if (inode)
++			err = au_reval_dpath(dentry, sigen);
++		if (unlikely(err))
++			goto out_dgrade;
++		AuDebugOn(au_digen(dentry) != sigen);
++	}
++	if (inode && au_iigen(inode) != sigen) {
++		AuDebugOn(IS_ROOT(dentry));
++		err = au_refresh_hinode(inode, dentry);
++		if (unlikely(err))
++			goto out_dgrade;
++		AuDebugOn(au_iigen(inode) != sigen);
++	}
++	di_downgrade_lock(dentry, AuLock_IR);
++
++	AuDebugOn(au_digen(dentry) != sigen);
++	AuDebugOn(inode && au_iigen(inode) != sigen);
++	err = -EINVAL;
++	do_udba = !au_opt_test(au_mntflags(sb), UDBA_NONE);
++	if (do_udba && inode) {
++		aufs_bindex_t bstart = au_ibstart(inode);
++
++		if (bstart >= 0
++		    && au_test_higen(inode, au_h_iptr(inode, bstart)))
++			goto out;
++	}
++
++	err = h_d_revalidate(dentry, inode, nd, do_udba);
++	if (unlikely(!err && do_udba && au_dbstart(dentry) < 0))
++		/* both of real entry and whiteout found */
++		err = -EIO;
++	goto out;
++
++ out_dgrade:
++	di_downgrade_lock(dentry, AuLock_IR);
++ out:
++	au_store_oflag(nd);
++	aufs_read_unlock(dentry, AuLock_IR);
++	AuTraceErr(err);
++	valid = !err;
++	if (!valid)
++		AuDbg("%.*s invalid\n", AuDLNPair(dentry));
++	return valid;
++}
++
++static void aufs_d_release(struct dentry *dentry)
++{
++	struct au_dinfo *dinfo;
++	aufs_bindex_t bend, bindex;
++
++	dinfo = dentry->d_fsdata;
++	if (!dinfo)
++		return;
++
++	/* dentry may not be revalidated */
++	bindex = dinfo->di_bstart;
++	if (bindex >= 0) {
++		struct au_hdentry *p;
++
++		bend = dinfo->di_bend;
++		p = dinfo->di_hdentry + bindex;
++		while (bindex++ <= bend) {
++			if (p->hd_dentry)
++				au_hdput(p);
++			p++;
++		}
++	}
++	kfree(dinfo->di_hdentry);
++	au_rwsem_destroy(&dinfo->di_rwsem);
++	au_cache_free_dinfo(dinfo);
++	au_hin_di_reinit(dentry);
++}
++
++struct dentry_operations aufs_dop = {
++	.d_revalidate	= aufs_d_revalidate,
++	.d_release	= aufs_d_release
++};
+diff -uNr test/fs/aufs/dentry.h aufs2-standalone/fs/aufs/dentry.h
+--- test/fs/aufs/dentry.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/dentry.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,213 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * lookup and dentry operations
++ */
++
++#ifndef __AUFS_DENTRY_H__
++#define __AUFS_DENTRY_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/namei.h>
++#include <linux/aufs_type.h>
++#include "rwsem.h"
++
++/* make a single member structure for future use */
++/* todo: remove this structure */
++struct au_hdentry {
++	struct dentry		*hd_dentry;
++};
++
++struct au_dinfo {
++	atomic_t		di_generation;
++
++	struct rw_semaphore	di_rwsem;
++	aufs_bindex_t		di_bstart, di_bend, di_bwh, di_bdiropq;
++	struct au_hdentry	*di_hdentry;
++};
++
++/* ---------------------------------------------------------------------- */
++
++/* dentry.c */
++extern struct dentry_operations aufs_dop;
++struct au_branch;
++struct dentry *au_lkup_one(struct qstr *name, struct dentry *h_parent,
++			   struct au_branch *br, struct nameidata *nd);
++struct dentry *au_sio_lkup_one(struct qstr *name, struct dentry *parent,
++			       struct au_branch *br);
++int au_h_verify(struct dentry *h_dentry, unsigned int udba, struct inode *h_dir,
++		struct dentry *h_parent, struct au_branch *br);
++
++int au_lkup_dentry(struct dentry *dentry, aufs_bindex_t bstart, mode_t type,
++		   struct nameidata *nd);
++int au_lkup_neg(struct dentry *dentry, aufs_bindex_t bindex);
++int au_refresh_hdentry(struct dentry *dentry, mode_t type);
++int au_reval_dpath(struct dentry *dentry, unsigned int sigen);
++
++/* dinfo.c */
++int au_alloc_dinfo(struct dentry *dentry);
++int au_di_realloc(struct au_dinfo *dinfo, int nbr);
++
++void di_read_lock(struct dentry *d, int flags, unsigned int lsc);
++void di_read_unlock(struct dentry *d, int flags);
++void di_downgrade_lock(struct dentry *d, int flags);
++void di_write_lock(struct dentry *d, unsigned int lsc);
++void di_write_unlock(struct dentry *d);
++void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir);
++void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir);
++void di_write_unlock2(struct dentry *d1, struct dentry *d2);
++
++struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex);
++aufs_bindex_t au_dbtail(struct dentry *dentry);
++aufs_bindex_t au_dbtaildir(struct dentry *dentry);
++
++void au_set_h_dptr(struct dentry *dentry, aufs_bindex_t bindex,
++		   struct dentry *h_dentry);
++void au_update_digen(struct dentry *dentry);
++void au_update_dbrange(struct dentry *dentry, int do_put_zero);
++void au_update_dbstart(struct dentry *dentry);
++void au_update_dbend(struct dentry *dentry);
++int au_find_dbindex(struct dentry *dentry, struct dentry *h_dentry);
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct au_dinfo *au_di(struct dentry *dentry)
++{
++	return dentry->d_fsdata;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* lock subclass for dinfo */
++enum {
++	AuLsc_DI_CHILD,		/* child first */
++	AuLsc_DI_CHILD2,	/* rename(2), link(2), and cpup at hinotify */
++	AuLsc_DI_CHILD3,	/* copyup dirs */
++	AuLsc_DI_PARENT,
++	AuLsc_DI_PARENT2,
++	AuLsc_DI_PARENT3
++};
++
++/*
++ * di_read_lock_child, di_write_lock_child,
++ * di_read_lock_child2, di_write_lock_child2,
++ * di_read_lock_child3, di_write_lock_child3,
++ * di_read_lock_parent, di_write_lock_parent,
++ * di_read_lock_parent2, di_write_lock_parent2,
++ * di_read_lock_parent3, di_write_lock_parent3,
++ */
++#define AuReadLockFunc(name, lsc) \
++static inline void di_read_lock_##name(struct dentry *d, int flags) \
++{ di_read_lock(d, flags, AuLsc_DI_##lsc); }
++
++#define AuWriteLockFunc(name, lsc) \
++static inline void di_write_lock_##name(struct dentry *d) \
++{ di_write_lock(d, AuLsc_DI_##lsc); }
++
++#define AuRWLockFuncs(name, lsc) \
++	AuReadLockFunc(name, lsc) \
++	AuWriteLockFunc(name, lsc)
++
++AuRWLockFuncs(child, CHILD);
++AuRWLockFuncs(child2, CHILD2);
++AuRWLockFuncs(child3, CHILD3);
++AuRWLockFuncs(parent, PARENT);
++AuRWLockFuncs(parent2, PARENT2);
++AuRWLockFuncs(parent3, PARENT3);
++
++#undef AuReadLockFunc
++#undef AuWriteLockFunc
++#undef AuRWLockFuncs
++
++#define DiMustNoWaiters(d)	AuRwMustNoWaiters(&au_di(d)->di_rwsem)
++
++/* ---------------------------------------------------------------------- */
++
++/* todo: memory barrier? */
++static inline unsigned int au_digen(struct dentry *d)
++{
++	return atomic_read(&au_di(d)->di_generation);
++}
++
++static inline void au_h_dentry_init(struct au_hdentry *hdentry)
++{
++	hdentry->hd_dentry = NULL;
++}
++
++static inline void au_hdput(struct au_hdentry *hd)
++{
++	dput(hd->hd_dentry);
++}
++
++static inline aufs_bindex_t au_dbstart(struct dentry *dentry)
++{
++	return au_di(dentry)->di_bstart;
++}
++
++static inline aufs_bindex_t au_dbend(struct dentry *dentry)
++{
++	return au_di(dentry)->di_bend;
++}
++
++static inline aufs_bindex_t au_dbwh(struct dentry *dentry)
++{
++	return au_di(dentry)->di_bwh;
++}
++
++static inline aufs_bindex_t au_dbdiropq(struct dentry *dentry)
++{
++	return au_di(dentry)->di_bdiropq;
++}
++
++/* todo: hard/soft set? */
++static inline void au_set_dbstart(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	au_di(dentry)->di_bstart = bindex;
++}
++
++static inline void au_set_dbend(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	au_di(dentry)->di_bend = bindex;
++}
++
++static inline void au_set_dbwh(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	/* dbwh can be outside of bstart - bend range */
++	au_di(dentry)->di_bwh = bindex;
++}
++
++static inline void au_set_dbdiropq(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	au_di(dentry)->di_bdiropq = bindex;
++}
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_HINOTIFY
++static inline void au_digen_dec(struct dentry *d)
++{
++	atomic_dec(&au_di(d)->di_generation);
++}
++
++static inline void au_hin_di_reinit(struct dentry *dentry)
++{
++	dentry->d_fsdata = NULL;
++}
++#else
++static inline void au_hin_di_reinit(struct dentry *dentry __maybe_unused)
++{
++	/* empty */
++}
++#endif /* CONFIG_AUFS_HINOTIFY */
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_DENTRY_H__ */
+diff -uNr test/fs/aufs/dinfo.c aufs2-standalone/fs/aufs/dinfo.c
+--- test/fs/aufs/dinfo.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/dinfo.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,351 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * dentry private data
++ */
++
++#include "aufs.h"
++
++int au_alloc_dinfo(struct dentry *dentry)
++{
++	struct au_dinfo *dinfo;
++	struct super_block *sb;
++	int nbr;
++
++	dinfo = au_cache_alloc_dinfo();
++	if (unlikely(!dinfo))
++		goto out;
++
++	sb = dentry->d_sb;
++	nbr = au_sbend(sb) + 1;
++	if (nbr <= 0)
++		nbr = 1;
++	dinfo->di_hdentry = kcalloc(nbr, sizeof(*dinfo->di_hdentry), GFP_NOFS);
++	if (unlikely(!dinfo->di_hdentry))
++		goto out_dinfo;
++
++	atomic_set(&dinfo->di_generation, au_sigen(sb));
++	/* smp_mb(); */ /* atomic_set */
++	init_rwsem(&dinfo->di_rwsem);
++	down_write_nested(&dinfo->di_rwsem, AuLsc_DI_CHILD);
++	dinfo->di_bstart = -1;
++	dinfo->di_bend = -1;
++	dinfo->di_bwh = -1;
++	dinfo->di_bdiropq = -1;
++
++	dentry->d_fsdata = dinfo;
++	dentry->d_op = &aufs_dop;
++	return 0; /* success */
++
++ out_dinfo:
++	au_cache_free_dinfo(dinfo);
++ out:
++	return -ENOMEM;
++}
++
++int au_di_realloc(struct au_dinfo *dinfo, int nbr)
++{
++	int err, sz;
++	struct au_hdentry *hdp;
++
++	err = -ENOMEM;
++	sz = sizeof(*hdp) * (dinfo->di_bend + 1);
++	if (!sz)
++		sz = sizeof(*hdp);
++	hdp = au_kzrealloc(dinfo->di_hdentry, sz, sizeof(*hdp) * nbr, GFP_NOFS);
++	if (hdp) {
++		dinfo->di_hdentry = hdp;
++		err = 0;
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void do_ii_write_lock(struct inode *inode, unsigned int lsc)
++{
++	switch (lsc) {
++	case AuLsc_DI_CHILD:
++		ii_write_lock_child(inode);
++		break;
++	case AuLsc_DI_CHILD2:
++		ii_write_lock_child2(inode);
++		break;
++	case AuLsc_DI_CHILD3:
++		ii_write_lock_child3(inode);
++		break;
++	case AuLsc_DI_PARENT:
++		ii_write_lock_parent(inode);
++		break;
++	case AuLsc_DI_PARENT2:
++		ii_write_lock_parent2(inode);
++		break;
++	case AuLsc_DI_PARENT3:
++		ii_write_lock_parent3(inode);
++		break;
++	default:
++		BUG();
++	}
++}
++
++static void do_ii_read_lock(struct inode *inode, unsigned int lsc)
++{
++	switch (lsc) {
++	case AuLsc_DI_CHILD:
++		ii_read_lock_child(inode);
++		break;
++	case AuLsc_DI_CHILD2:
++		ii_read_lock_child2(inode);
++		break;
++	case AuLsc_DI_CHILD3:
++		ii_read_lock_child3(inode);
++		break;
++	case AuLsc_DI_PARENT:
++		ii_read_lock_parent(inode);
++		break;
++	case AuLsc_DI_PARENT2:
++		ii_read_lock_parent2(inode);
++		break;
++	case AuLsc_DI_PARENT3:
++		ii_read_lock_parent3(inode);
++		break;
++	default:
++		BUG();
++	}
++}
++
++void di_read_lock(struct dentry *d, int flags, unsigned int lsc)
++{
++	down_read_nested(&au_di(d)->di_rwsem, lsc);
++	if (d->d_inode) {
++		if (au_ftest_lock(flags, IW))
++			do_ii_write_lock(d->d_inode, lsc);
++		else if (au_ftest_lock(flags, IR))
++			do_ii_read_lock(d->d_inode, lsc);
++	}
++}
++
++void di_read_unlock(struct dentry *d, int flags)
++{
++	if (d->d_inode) {
++		if (au_ftest_lock(flags, IW))
++			ii_write_unlock(d->d_inode);
++		else if (au_ftest_lock(flags, IR))
++			ii_read_unlock(d->d_inode);
++	}
++	up_read(&au_di(d)->di_rwsem);
++}
++
++void di_downgrade_lock(struct dentry *d, int flags)
++{
++	downgrade_write(&au_di(d)->di_rwsem);
++	if (d->d_inode && au_ftest_lock(flags, IR))
++		ii_downgrade_lock(d->d_inode);
++}
++
++void di_write_lock(struct dentry *d, unsigned int lsc)
++{
++	down_write_nested(&au_di(d)->di_rwsem, lsc);
++	if (d->d_inode)
++		do_ii_write_lock(d->d_inode, lsc);
++}
++
++void di_write_unlock(struct dentry *d)
++{
++	if (d->d_inode)
++		ii_write_unlock(d->d_inode);
++	up_write(&au_di(d)->di_rwsem);
++}
++
++void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir)
++{
++	AuDebugOn(d1 == d2
++		  || d1->d_inode == d2->d_inode
++		  || d1->d_sb != d2->d_sb);
++
++	if (isdir && au_test_subdir(d1, d2)) {
++		di_write_lock_child(d1);
++		di_write_lock_child2(d2);
++	} else {
++		/* there should be no races */
++		di_write_lock_child(d2);
++		di_write_lock_child2(d1);
++	}
++}
++
++void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir)
++{
++	AuDebugOn(d1 == d2
++		  || d1->d_inode == d2->d_inode
++		  || d1->d_sb != d2->d_sb);
++
++	if (isdir && au_test_subdir(d1, d2)) {
++		di_write_lock_parent(d1);
++		di_write_lock_parent2(d2);
++	} else {
++		/* there should be no races */
++		di_write_lock_parent(d2);
++		di_write_lock_parent2(d1);
++	}
++}
++
++void di_write_unlock2(struct dentry *d1, struct dentry *d2)
++{
++	di_write_unlock(d1);
++	if (d1->d_inode == d2->d_inode)
++		up_write(&au_di(d2)->di_rwsem);
++	else
++		di_write_unlock(d2);
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	struct dentry *d;
++
++	if (au_dbstart(dentry) < 0 || bindex < au_dbstart(dentry))
++		return NULL;
++	AuDebugOn(bindex < 0);
++	d = au_di(dentry)->di_hdentry[0 + bindex].hd_dentry;
++	AuDebugOn(d && (atomic_read(&d->d_count) <= 0));
++	return d;
++}
++
++aufs_bindex_t au_dbtail(struct dentry *dentry)
++{
++	aufs_bindex_t bend, bwh;
++
++	bend = au_dbend(dentry);
++	if (0 <= bend) {
++		bwh = au_dbwh(dentry);
++		if (!bwh)
++			return bwh;
++		if (0 < bwh && bwh < bend)
++			return bwh - 1;
++	}
++	return bend;
++}
++
++aufs_bindex_t au_dbtaildir(struct dentry *dentry)
++{
++	aufs_bindex_t bend, bopq;
++
++	bend = au_dbtail(dentry);
++	if (0 <= bend) {
++		bopq = au_dbdiropq(dentry);
++		if (0 <= bopq && bopq < bend)
++			bend = bopq;
++	}
++	return bend;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_set_h_dptr(struct dentry *dentry, aufs_bindex_t bindex,
++		   struct dentry *h_dentry)
++{
++	struct au_hdentry *hd = au_di(dentry)->di_hdentry + bindex;
++
++	if (hd->hd_dentry)
++		au_hdput(hd);
++	hd->hd_dentry = h_dentry;
++}
++
++void au_update_digen(struct dentry *dentry)
++{
++	atomic_set(&au_di(dentry)->di_generation, au_sigen(dentry->d_sb));
++	/* smp_mb(); */ /* atomic_set */
++}
++
++void au_update_dbrange(struct dentry *dentry, int do_put_zero)
++{
++	struct au_dinfo *dinfo;
++	struct dentry *h_d;
++
++	dinfo = au_di(dentry);
++	if (!dinfo || dinfo->di_bstart < 0)
++		return;
++
++	if (do_put_zero) {
++		aufs_bindex_t bindex, bend;
++
++		bend = dinfo->di_bend;
++		for (bindex = dinfo->di_bstart; bindex <= bend; bindex++) {
++			h_d = dinfo->di_hdentry[0 + bindex].hd_dentry;
++			if (h_d && !h_d->d_inode)
++				au_set_h_dptr(dentry, bindex, NULL);
++		}
++	}
++
++	dinfo->di_bstart = -1;
++	while (++dinfo->di_bstart <= dinfo->di_bend)
++		if (dinfo->di_hdentry[0 + dinfo->di_bstart].hd_dentry)
++			break;
++	if (dinfo->di_bstart > dinfo->di_bend) {
++		dinfo->di_bstart = -1;
++		dinfo->di_bend = -1;
++		return;
++	}
++
++	dinfo->di_bend++;
++	while (0 <= --dinfo->di_bend)
++		if (dinfo->di_hdentry[0 + dinfo->di_bend].hd_dentry)
++			break;
++	AuDebugOn(dinfo->di_bstart > dinfo->di_bend || dinfo->di_bend < 0);
++}
++
++void au_update_dbstart(struct dentry *dentry)
++{
++	aufs_bindex_t bindex, bend;
++	struct dentry *h_dentry;
++
++	bend = au_dbend(dentry);
++	for (bindex = au_dbstart(dentry); bindex <= bend; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++		if (h_dentry->d_inode) {
++			au_set_dbstart(dentry, bindex);
++			return;
++		}
++		au_set_h_dptr(dentry, bindex, NULL);
++	}
++}
++
++void au_update_dbend(struct dentry *dentry)
++{
++	aufs_bindex_t bindex, bstart;
++	struct dentry *h_dentry;
++
++	bstart = au_dbstart(dentry);
++	for (bindex = au_dbend(dentry); bindex <= bstart; bindex--) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++		if (h_dentry->d_inode) {
++			au_set_dbend(dentry, bindex);
++			return;
++		}
++		au_set_h_dptr(dentry, bindex, NULL);
++	}
++}
++
++int au_find_dbindex(struct dentry *dentry, struct dentry *h_dentry)
++{
++	aufs_bindex_t bindex, bend;
++
++	bend = au_dbend(dentry);
++	for (bindex = au_dbstart(dentry); bindex <= bend; bindex++)
++		if (au_h_dptr(dentry, bindex) == h_dentry)
++			return bindex;
++	return -1;
++}
+diff -uNr test/fs/aufs/dir.c aufs2-standalone/fs/aufs/dir.c
+--- test/fs/aufs/dir.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/dir.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,493 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * directory operations
++ */
++
++#include <linux/fs_stack.h>
++#include "aufs.h"
++
++void au_add_nlink(struct inode *dir, struct inode *h_dir)
++{
++	AuDebugOn(!S_ISDIR(dir->i_mode) || !S_ISDIR(h_dir->i_mode));
++
++	dir->i_nlink += h_dir->i_nlink - 2;
++	if (h_dir->i_nlink < 2)
++		dir->i_nlink += 2;
++}
++
++void au_sub_nlink(struct inode *dir, struct inode *h_dir)
++{
++	AuDebugOn(!S_ISDIR(dir->i_mode) || !S_ISDIR(h_dir->i_mode));
++
++	dir->i_nlink -= h_dir->i_nlink - 2;
++	if (h_dir->i_nlink < 2)
++		dir->i_nlink -= 2;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int reopen_dir(struct file *file)
++{
++	int err;
++	unsigned int flags;
++	aufs_bindex_t bindex, btail, bstart;
++	struct dentry *dentry, *h_dentry;
++	struct file *h_file;
++
++	/* open all lower dirs */
++	dentry = file->f_dentry;
++	bstart = au_dbstart(dentry);
++	for (bindex = au_fbstart(file); bindex < bstart; bindex++)
++		au_set_h_fptr(file, bindex, NULL);
++	au_set_fbstart(file, bstart);
++
++	btail = au_dbtaildir(dentry);
++	for (bindex = au_fbend(file); btail < bindex; bindex--)
++		au_set_h_fptr(file, bindex, NULL);
++	au_set_fbend(file, btail);
++
++	flags = file->f_flags;
++	for (bindex = bstart; bindex <= btail; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++		h_file = au_h_fptr(file, bindex);
++		if (h_file)
++			continue;
++
++		h_file = au_h_open(dentry, bindex, flags, file);
++		err = PTR_ERR(h_file);
++		if (IS_ERR(h_file))
++			goto out; /* close all? */
++		au_set_h_fptr(file, bindex, h_file);
++	}
++	au_update_figen(file);
++	/* todo: necessary? */
++	/* file->f_ra = h_file->f_ra; */
++	err = 0;
++
++ out:
++	return err;
++}
++
++static int do_open_dir(struct file *file, int flags)
++{
++	int err;
++	aufs_bindex_t bindex, btail;
++	struct dentry *dentry, *h_dentry;
++	struct file *h_file;
++
++	err = 0;
++	dentry = file->f_dentry;
++	au_set_fvdir_cache(file, NULL);
++	au_fi(file)->fi_maintain_plink = 0;
++	file->f_version = dentry->d_inode->i_version;
++	bindex = au_dbstart(dentry);
++	au_set_fbstart(file, bindex);
++	btail = au_dbtaildir(dentry);
++	au_set_fbend(file, btail);
++	for (; !err && bindex <= btail; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++
++		h_file = au_h_open(dentry, bindex, flags, file);
++		if (IS_ERR(h_file)) {
++			err = PTR_ERR(h_file);
++			break;
++		}
++		au_set_h_fptr(file, bindex, h_file);
++	}
++	au_update_figen(file);
++	/* todo: necessary? */
++	/* file->f_ra = h_file->f_ra; */
++	if (!err)
++		return 0; /* success */
++
++	/* close all */
++	for (bindex = au_fbstart(file); bindex <= btail; bindex++)
++		au_set_h_fptr(file, bindex, NULL);
++	au_set_fbstart(file, -1);
++	au_set_fbend(file, -1);
++	return err;
++}
++
++static int aufs_open_dir(struct inode *inode __maybe_unused,
++			 struct file *file)
++{
++	return au_do_open(file, do_open_dir);
++}
++
++static int aufs_release_dir(struct inode *inode __maybe_unused,
++			    struct file *file)
++{
++	struct au_vdir *vdir_cache;
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++
++	sb = file->f_dentry->d_sb;
++	si_noflush_read_lock(sb);
++	fi_write_lock(file);
++	vdir_cache = au_fvdir_cache(file);
++	if (vdir_cache)
++		au_vdir_free(vdir_cache);
++	if (au_fi(file)->fi_maintain_plink) {
++		sbinfo = au_sbi(sb);
++		au_fclr_si(sbinfo, MAINTAIN_PLINK);
++		wake_up_all(&sbinfo->si_plink_wq);
++	}
++	fi_write_unlock(file);
++	au_finfo_fin(file);
++	si_read_unlock(sb);
++	return 0;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_do_fsync_dir_no_file(struct dentry *dentry, int datasync)
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct inode *inode;
++	struct super_block *sb;
++
++	err = 0;
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	IMustLock(inode);
++	bend = au_dbend(dentry);
++	for (bindex = au_dbstart(dentry); !err && bindex <= bend; bindex++) {
++		struct path h_path;
++		struct inode *h_inode;
++		struct file_operations *fop;
++
++		if (au_test_ro(sb, bindex, inode))
++			continue;
++		h_path.dentry = au_h_dptr(dentry, bindex);
++		if (!h_path.dentry)
++			continue;
++		h_inode = h_path.dentry->d_inode;
++		if (!h_inode)
++			continue;
++
++		/* no mnt_want_write() */
++		/* cf. fs/nsfd/vfs.c and fs/nfsd/nfs4recover.c */
++		/* todo: inotiry fired? */
++		h_path.mnt = au_sbr_mnt(sb, bindex);
++		mutex_lock(&h_inode->i_mutex);
++		fop = (void *)h_inode->i_fop;
++		err = filemap_fdatawrite(h_inode->i_mapping);
++		if (!err && fop && fop->fsync)
++			err = fop->fsync(NULL, h_path.dentry, datasync);
++		if (!err)
++			err = filemap_fdatawrite(h_inode->i_mapping);
++		if (!err)
++			vfsub_update_h_iattr(&h_path, /*did*/NULL); /*ignore*/
++		mutex_unlock(&h_inode->i_mutex);
++	}
++
++	return err;
++}
++
++static int au_do_fsync_dir(struct file *file, int datasync)
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct file *h_file;
++	struct super_block *sb;
++	struct inode *inode;
++	struct mutex *h_mtx;
++
++	err = au_reval_and_lock_fdi(file, reopen_dir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	sb = file->f_dentry->d_sb;
++	inode = file->f_dentry->d_inode;
++	bend = au_fbend(file);
++	for (bindex = au_fbstart(file); !err && bindex <= bend; bindex++) {
++		h_file = au_h_fptr(file, bindex);
++		if (!h_file || au_test_ro(sb, bindex, inode))
++			continue;
++
++		err = (int)do_fsync(h_file, datasync);
++		if (!err) {
++			h_mtx = &h_file->f_dentry->d_inode->i_mutex;
++			mutex_lock(h_mtx);
++			vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL);
++			/*ignore*/
++			mutex_unlock(h_mtx);
++		}
++	}
++
++ out:
++	return err;
++}
++
++/*
++ * @file may be NULL
++ */
++static int aufs_fsync_dir(struct file *file, struct dentry *dentry,
++			  int datasync)
++{
++	int err;
++	struct super_block *sb;
++
++	IMustLock(dentry->d_inode);
++
++	err = 0;
++	sb = dentry->d_sb;
++	si_noflush_read_lock(sb);
++	if (file)
++		err = au_do_fsync_dir(file, datasync);
++	else {
++		di_write_lock_child(dentry);
++		err = au_do_fsync_dir_no_file(dentry, datasync);
++	}
++	au_cpup_attr_timesizes(dentry->d_inode);
++	di_write_unlock(dentry);
++	if (file)
++		fi_write_unlock(file);
++
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int aufs_readdir(struct file *file, void *dirent, filldir_t filldir)
++{
++	int err;
++	struct dentry *dentry;
++	struct inode *inode;
++	struct super_block *sb;
++
++	dentry = file->f_dentry;
++	inode = dentry->d_inode;
++	IMustLock(inode);
++
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	err = au_reval_and_lock_fdi(file, reopen_dir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++	err = au_vdir_init(file);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err))
++		goto out_unlock;
++
++	err = au_vdir_fill_de(file, dirent, filldir);
++	fsstack_copy_attr_atime(inode, au_h_iptr(inode, au_ibstart(inode)));
++
++ out_unlock:
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++ out:
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++#define AuTestEmpty_WHONLY	1
++#define AuTestEmpty_CALLED	(1 << 2)
++#define au_ftest_testempty(flags, name)	((flags) & AuTestEmpty_##name)
++#define au_fset_testempty(flags, name)	{ (flags) |= AuTestEmpty_##name; }
++#define au_fclr_testempty(flags, name)	{ (flags) &= ~AuTestEmpty_##name; }
++
++struct test_empty_arg {
++	struct au_nhash *whlist;
++	unsigned int flags;
++	int err;
++	aufs_bindex_t bindex;
++};
++
++static int test_empty_cb(void *__arg, const char *__name, int namelen,
++			 loff_t offset __maybe_unused, u64 ino __maybe_unused,
++			 unsigned int d_type __maybe_unused)
++{
++	struct test_empty_arg *arg = __arg;
++	char *name = (void *)__name;
++
++	arg->err = 0;
++	au_fset_testempty(arg->flags, CALLED);
++	/* smp_mb(); */
++	if (name[0] == '.'
++	    && (namelen == 1 || (name[1] == '.' && namelen == 2)))
++		goto out; /* success */
++
++	if (namelen <= AUFS_WH_PFX_LEN
++	    || memcmp(name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
++		if (au_ftest_testempty(arg->flags, WHONLY)
++		    && !au_nhash_test_known_wh(arg->whlist, name, namelen))
++			arg->err = -ENOTEMPTY;
++		goto out;
++	}
++
++	name += AUFS_WH_PFX_LEN;
++	namelen -= AUFS_WH_PFX_LEN;
++	if (!au_nhash_test_known_wh(arg->whlist, name, namelen))
++		arg->err = au_nhash_append_wh
++			(arg->whlist, name, namelen, arg->bindex);
++
++ out:
++	/* smp_mb(); */
++	AuTraceErr(arg->err);
++	return arg->err;
++}
++
++static int do_test_empty(struct dentry *dentry, struct test_empty_arg *arg)
++{
++	int err;
++	struct file *h_file;
++
++	h_file = au_h_open(dentry, arg->bindex,
++			   O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_LARGEFILE,
++			   /*file*/NULL);
++	err = PTR_ERR(h_file);
++	if (IS_ERR(h_file))
++		goto out;
++
++	err = 0;
++	if (!au_opt_test(au_mntflags(dentry->d_sb), UDBA_NONE)
++	    && !h_file->f_dentry->d_inode->i_nlink)
++		goto out_put;
++
++	do {
++		arg->err = 0;
++		au_fclr_testempty(arg->flags, CALLED);
++		/* smp_mb(); */
++		err = vfsub_readdir(h_file, test_empty_cb, arg);
++		if (err >= 0)
++			err = arg->err;
++	} while (!err && au_ftest_testempty(arg->flags, CALLED));
++
++ out_put:
++	fput(h_file);
++	au_sbr_put(dentry->d_sb, arg->bindex);
++ out:
++	return err;
++}
++
++struct do_test_empty_args {
++	int *errp;
++	struct dentry *dentry;
++	struct test_empty_arg *arg;
++};
++
++static void call_do_test_empty(void *args)
++{
++	struct do_test_empty_args *a = args;
++	*a->errp = do_test_empty(a->dentry, a->arg);
++}
++
++static int sio_test_empty(struct dentry *dentry, struct test_empty_arg *arg)
++{
++	int err, wkq_err;
++	struct dentry *h_dentry;
++	struct inode *h_inode;
++
++	h_dentry = au_h_dptr(dentry, arg->bindex);
++	h_inode = h_dentry->d_inode;
++	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++	err = au_test_h_perm_sio(h_inode, MAY_EXEC | MAY_READ);
++	mutex_unlock(&h_inode->i_mutex);
++	if (!err)
++		err = do_test_empty(dentry, arg);
++	else {
++		struct do_test_empty_args args = {
++			.errp	= &err,
++			.dentry	= dentry,
++			.arg	= arg
++		};
++		unsigned int flags = arg->flags;
++
++		wkq_err = au_wkq_wait(call_do_test_empty, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++		arg->flags = flags;
++	}
++
++	return err;
++}
++
++int au_test_empty_lower(struct dentry *dentry)
++{
++	int err;
++	aufs_bindex_t bindex, bstart, btail;
++	struct test_empty_arg arg;
++	struct au_nhash *whlist;
++
++	whlist = au_nhash_new(GFP_NOFS);
++	err = PTR_ERR(whlist);
++	if (IS_ERR(whlist))
++		goto out;
++
++	bstart = au_dbstart(dentry);
++	arg.whlist = whlist;
++	arg.flags = 0;
++	arg.bindex = bstart;
++	err = do_test_empty(dentry, &arg);
++	if (unlikely(err))
++		goto out_whlist;
++
++	au_fset_testempty(arg.flags, WHONLY);
++	btail = au_dbtaildir(dentry);
++	for (bindex = bstart + 1; !err && bindex <= btail; bindex++) {
++		struct dentry *h_dentry;
++
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (h_dentry && h_dentry->d_inode) {
++			arg.bindex = bindex;
++			err = do_test_empty(dentry, &arg);
++		}
++	}
++
++ out_whlist:
++	au_nhash_del(whlist);
++ out:
++	return err;
++}
++
++int au_test_empty(struct dentry *dentry, struct au_nhash *whlist)
++{
++	int err;
++	struct test_empty_arg arg;
++	aufs_bindex_t bindex, btail;
++
++	err = 0;
++	arg.whlist = whlist;
++	arg.flags = AuTestEmpty_WHONLY;
++	btail = au_dbtaildir(dentry);
++	for (bindex = au_dbstart(dentry); !err && bindex <= btail; bindex++) {
++		struct dentry *h_dentry;
++
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (h_dentry && h_dentry->d_inode) {
++			arg.bindex = bindex;
++			err = sio_test_empty(dentry, &arg);
++		}
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct file_operations aufs_dir_fop = {
++	.read		= generic_read_dir,
++	.readdir	= aufs_readdir,
++	.unlocked_ioctl	= aufs_ioctl_dir,
++	.open		= aufs_open_dir,
++	.release	= aufs_release_dir,
++	.flush		= aufs_flush,
++	.fsync		= aufs_fsync_dir
++};
+diff -uNr test/fs/aufs/dir.h aufs2-standalone/fs/aufs/dir.h
+--- test/fs/aufs/dir.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/dir.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,104 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * directory operations
++ */
++
++#ifndef __AUFS_DIR_H__
++#define __AUFS_DIR_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/aufs_type.h>
++
++/* ---------------------------------------------------------------------- */
++
++/* need to be faster and smaller */
++
++#define AuSize_DEBLK	512
++#define AuSize_NHASH	32
++
++typedef char au_vdir_deblk_t[AuSize_DEBLK];
++
++struct au_nhash {
++	struct hlist_head heads[AuSize_NHASH];
++};
++
++struct au_vdir_destr {
++	unsigned char	len;
++	char		name[0];
++} __packed;
++
++struct au_vdir_dehstr {
++	struct hlist_node	hash;
++	struct au_vdir_destr	*str;
++};
++
++struct au_vdir_de {
++	ino_t			de_ino;
++	unsigned char		de_type;
++	/* caution: packed */
++	struct au_vdir_destr	de_str;
++} __packed;
++
++struct au_vdir_wh {
++	struct hlist_node	wh_hash;
++	aufs_bindex_t		wh_bindex;
++	struct au_vdir_destr	wh_str;
++} __packed;
++
++union au_vdir_deblk_p {
++	unsigned char		*p;
++	au_vdir_deblk_t		*deblk;
++	struct au_vdir_de	*de;
++};
++
++struct au_vdir {
++	au_vdir_deblk_t	**vd_deblk;
++	int		vd_nblk;
++	struct {
++		int			i;
++		union au_vdir_deblk_p	p;
++	} vd_last;
++
++	unsigned long	vd_version;
++	unsigned long	vd_jiffy;
++};
++
++/* ---------------------------------------------------------------------- */
++
++/* dir.c */
++extern struct file_operations aufs_dir_fop;
++void au_add_nlink(struct inode *dir, struct inode *h_dir);
++void au_sub_nlink(struct inode *dir, struct inode *h_dir);
++int au_test_empty_lower(struct dentry *dentry);
++int au_test_empty(struct dentry *dentry, struct au_nhash *whlist);
++
++/* vdir.c */
++struct au_nhash *au_nhash_new(gfp_t gfp);
++void au_nhash_del(struct au_nhash *nhash);
++void au_nhash_init(struct au_nhash *nhash);
++void au_nhash_move(struct au_nhash *dst, struct au_nhash *src);
++void au_nhash_fin(struct au_nhash *nhash);
++int au_nhash_test_longer_wh(struct au_nhash *whlist, aufs_bindex_t btgt,
++			    int limit);
++int au_nhash_test_known_wh(struct au_nhash *whlist, char *name, int namelen);
++int au_nhash_append_wh(struct au_nhash *whlist, char *name, int namelen,
++		       aufs_bindex_t bindex);
++void au_vdir_free(struct au_vdir *vdir);
++int au_vdir_init(struct file *file);
++int au_vdir_fill_de(struct file *file, void *dirent, filldir_t filldir);
++
++/* ioctl.c */
++long aufs_ioctl_dir(struct file *file, unsigned int cmd, unsigned long arg);
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_DIR_H__ */
+diff -uNr test/fs/aufs/f_op.c aufs2-standalone/fs/aufs/f_op.c
+--- test/fs/aufs/f_op.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/f_op.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,551 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * file and vm operations
++ */
++
++#include <linux/fs_stack.h>
++#include <linux/poll.h>
++#include "aufs.h"
++
++/* common function to regular file and dir */
++int aufs_flush(struct file *file, fl_owner_t id)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	struct dentry *dentry;
++	struct file *h_file;
++
++	dentry = file->f_dentry;
++	si_noflush_read_lock(dentry->d_sb);
++	fi_read_lock(file);
++	di_read_lock_child(dentry, AuLock_IW);
++
++	err = 0;
++	bend = au_fbend(file);
++	for (bindex = au_fbstart(file); !err && bindex <= bend; bindex++) {
++		h_file = au_h_fptr(file, bindex);
++		if (!h_file || !h_file->f_op || !h_file->f_op->flush)
++			continue;
++
++		err = h_file->f_op->flush(h_file, id);
++		if (!err)
++			vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL);
++		/*ignore*/
++	}
++	au_cpup_attr_timesizes(dentry->d_inode);
++
++	di_read_unlock(dentry, AuLock_IW);
++	fi_read_unlock(file);
++	si_read_unlock(dentry->d_sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int do_open_nondir(struct file *file, int flags)
++{
++	int err;
++	aufs_bindex_t bindex;
++	struct file *h_file;
++	struct dentry *dentry;
++
++	err = 0;
++	dentry = file->f_dentry;
++	au_fi(file)->fi_h_vm_ops = NULL;
++	bindex = au_dbstart(dentry);
++	/* O_TRUNC is processed already */
++	BUG_ON(au_test_ro(dentry->d_sb, bindex, dentry->d_inode)
++	       && (flags & O_TRUNC));
++
++	h_file = au_h_open(dentry, bindex, flags, file);
++	if (IS_ERR(h_file))
++		err = PTR_ERR(h_file);
++	else {
++		au_set_fbstart(file, bindex);
++		au_set_fbend(file, bindex);
++		au_set_h_fptr(file, bindex, h_file);
++		au_update_figen(file);
++		/* todo: necessary? */
++		/* file->f_ra = h_file->f_ra; */
++	}
++	return err;
++}
++
++static int aufs_open_nondir(struct inode *inode __maybe_unused,
++			    struct file *file)
++{
++	return au_do_open(file, do_open_nondir);
++}
++
++static int aufs_release_nondir(struct inode *inode __maybe_unused,
++			       struct file *file)
++{
++	struct super_block *sb = file->f_dentry->d_sb;
++
++	si_noflush_read_lock(sb);
++	au_finfo_fin(file);
++	si_read_unlock(sb);
++	return 0;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static ssize_t aufs_read(struct file *file, char __user *buf, size_t count,
++			 loff_t *ppos)
++{
++	ssize_t err;
++	struct dentry *dentry;
++	struct file *h_file;
++	struct super_block *sb;
++
++	dentry = file->f_dentry;
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
++	if (unlikely(err))
++		goto out;
++
++	h_file = au_h_fptr(file, au_fbstart(file));
++	err = vfsub_read_u(h_file, buf, count, ppos);
++	/* todo: necessary? */
++	/* file->f_ra = h_file->f_ra; */
++	fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
++
++	di_read_unlock(dentry, AuLock_IR);
++	fi_read_unlock(file);
++ out:
++	si_read_unlock(sb);
++	return err;
++}
++
++static ssize_t aufs_write(struct file *file, const char __user *ubuf,
++			  size_t count, loff_t *ppos)
++{
++	ssize_t err;
++	aufs_bindex_t bstart;
++	struct au_pin pin;
++	struct dentry *dentry;
++	struct inode *inode;
++	struct super_block *sb;
++	struct file *h_file;
++	char __user *buf = (char __user *)ubuf;
++
++	dentry = file->f_dentry;
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	mutex_lock(&inode->i_mutex);
++	si_read_lock(sb, AuLock_FLUSH);
++
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	err = au_ready_to_write(file, -1, &pin);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err))
++		goto out_unlock;
++
++	bstart = au_fbstart(file);
++	h_file = au_h_fptr(file, bstart);
++	au_unpin(&pin);
++	err = vfsub_write_u(h_file, buf, count, ppos);
++	au_cpup_attr_timesizes(inode);
++	inode->i_mode = h_file->f_dentry->d_inode->i_mode;
++
++ out_unlock:
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++ out:
++	si_read_unlock(sb);
++	mutex_unlock(&inode->i_mutex);
++	return err;
++}
++
++static ssize_t aufs_splice_read(struct file *file, loff_t *ppos,
++				struct pipe_inode_info *pipe, size_t len,
++				unsigned int flags)
++{
++	ssize_t err;
++	struct file *h_file;
++	struct dentry *dentry;
++	struct super_block *sb;
++
++	dentry = file->f_dentry;
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
++	if (unlikely(err))
++		goto out;
++
++	err = -EINVAL;
++	h_file = au_h_fptr(file, au_fbstart(file));
++	if (au_test_loopback_kthread()) {
++		file->f_mapping = h_file->f_mapping;
++		smp_mb(); /* unnecessary? */
++	}
++	err = vfsub_splice_to(h_file, ppos, pipe, len, flags);
++	/* todo: necessasry? */
++	/* file->f_ra = h_file->f_ra; */
++	fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
++
++	di_read_unlock(dentry, AuLock_IR);
++	fi_read_unlock(file);
++
++ out:
++	si_read_unlock(sb);
++	return err;
++}
++
++static ssize_t
++aufs_splice_write(struct pipe_inode_info *pipe, struct file *file, loff_t *ppos,
++		  size_t len, unsigned int flags)
++{
++	ssize_t err;
++	struct au_pin pin;
++	struct dentry *dentry;
++	struct inode *inode;
++	struct super_block *sb;
++	struct file *h_file;
++
++	dentry = file->f_dentry;
++	inode = dentry->d_inode;
++	mutex_lock(&inode->i_mutex);
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	err = au_ready_to_write(file, -1, &pin);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err))
++		goto out_unlock;
++
++	h_file = au_h_fptr(file, au_fbstart(file));
++	au_unpin(&pin);
++	err = vfsub_splice_from(pipe, h_file, ppos, len, flags);
++	au_cpup_attr_timesizes(inode);
++	inode->i_mode = h_file->f_dentry->d_inode->i_mode;
++
++ out_unlock:
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++ out:
++	si_read_unlock(sb);
++	mutex_unlock(&inode->i_mutex);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static struct file *au_safe_file(struct vm_area_struct *vma)
++{
++	struct file *file;
++
++	file = vma->vm_file;
++	if (file->private_data && au_test_aufs(file->f_dentry->d_sb))
++		return file;
++	return NULL;
++}
++
++static void au_reset_file(struct vm_area_struct *vma, struct file *file)
++{
++	vma->vm_file = file;
++	/* smp_mb(); */ /* flush vm_file */
++}
++
++static int aufs_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
++{
++	int err;
++	static DECLARE_WAIT_QUEUE_HEAD(wq);
++	struct file *file, *h_file;
++	struct au_finfo *finfo;
++
++	/* todo: non-robr mode, user vm_file as it is? */
++	wait_event(wq, (file = au_safe_file(vma)));
++
++	/* do not revalidate, no si lock */
++	finfo = au_fi(file);
++	h_file = finfo->fi_hfile[0 + finfo->fi_bstart].hf_file;
++	AuDebugOn(!h_file || !au_test_mmapped(file));
++
++	fi_write_lock(file);
++	vma->vm_file = h_file;
++	err = finfo->fi_h_vm_ops->fault(vma, vmf);
++	/* todo: necessary? */
++	/* file->f_ra = h_file->f_ra; */
++	au_reset_file(vma, file);
++	fi_write_unlock(file);
++#if 0 /* def CONFIG_SMP */
++	/* wake_up_nr(&wq, online_cpu - 1); */
++	wake_up_all(&wq);
++#else
++	wake_up(&wq);
++#endif
++
++	return err;
++}
++
++static struct vm_operations_struct aufs_vm_ops = {
++	.fault		= aufs_fault
++};
++
++/* ---------------------------------------------------------------------- */
++
++static struct vm_operations_struct *au_vm_ops(struct file *h_file,
++					      struct vm_area_struct *vma)
++{
++	struct vm_operations_struct *vm_ops;
++	int err;
++
++	err = h_file->f_op->mmap(h_file, vma);
++	vm_ops = ERR_PTR(err);
++	if (unlikely(err))
++		goto out;
++	vm_ops = vma->vm_ops;
++	err = do_munmap(current->mm, vma->vm_start,
++			vma->vm_end - vma->vm_start);
++	if (unlikely(err)) {
++		AuIOErr("failed internal unmapping %.*s, %d\n",
++			AuDLNPair(h_file->f_dentry), err);
++		vm_ops = ERR_PTR(-EIO);
++	}
++
++ out:
++	return vm_ops;
++}
++
++static int aufs_mmap(struct file *file, struct vm_area_struct *vma)
++{
++	int err;
++	unsigned char wlock, mmapped;
++	struct dentry *dentry;
++	struct super_block *sb;
++	struct file *h_file;
++	struct vm_operations_struct *vm_ops;
++
++	dentry = file->f_dentry;
++	mmapped = !!au_test_mmapped(file); /* can be harmless race condition */
++	wlock = !!(file->f_mode & FMODE_WRITE);
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, wlock | !mmapped);
++	if (unlikely(err))
++		goto out;
++
++	if (wlock) {
++		struct au_pin pin;
++
++		err = au_ready_to_write(file, -1, &pin);
++		di_downgrade_lock(dentry, AuLock_IR);
++		if (unlikely(err))
++			goto out_unlock;
++		au_unpin(&pin);
++	} else if (!mmapped)
++		di_downgrade_lock(dentry, AuLock_IR);
++
++	h_file = au_h_fptr(file, au_fbstart(file));
++	if (au_test_fs_bad_mapping(h_file->f_dentry->d_sb)) {
++		/*
++		 * by this assignment, f_mapping will differs from aufs inode
++		 * i_mapping.
++		 * if someone else mixes the use of f_dentry->d_inode and
++		 * f_mapping->host, then a problem may arise.
++		 */
++		file->f_mapping = h_file->f_mapping;
++	}
++
++	vm_ops = NULL;
++	if (!mmapped) {
++		vm_ops = au_vm_ops(h_file, vma);
++		err = PTR_ERR(vm_ops);
++		if (IS_ERR(vm_ops))
++			goto out_unlock;
++	}
++
++	/*
++	 * unnecessary to handle MAP_DENYWRITE and deny_write_access()?
++	 * currently MAP_DENYWRITE from userspace is ignored, but elf loader
++	 * sets it. when FMODE_EXEC is set (by open_exec() or sys_uselib()),
++	 * both of the aufs file and the lower file is deny_write_access()-ed.
++	 * finally I hope we can skip handlling MAP_DENYWRITE here.
++	 */
++	err = generic_file_mmap(file, vma);
++	if (unlikely(err))
++		goto out_unlock;
++	vma->vm_ops = &aufs_vm_ops;
++	/* test again */
++	if (!au_test_mmapped(file))
++		au_fi(file)->fi_h_vm_ops = vm_ops;
++
++	vfsub_file_accessed(h_file);
++	fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
++
++ out_unlock:
++	di_read_unlock(dentry, AuLock_IR);
++	if (!wlock && mmapped)
++		fi_read_unlock(file);
++	else
++		fi_write_unlock(file);
++ out:
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static unsigned int aufs_poll(struct file *file, poll_table *wait)
++{
++	unsigned int mask;
++	int err;
++	struct file *h_file;
++	struct dentry *dentry;
++	struct super_block *sb;
++
++	/* We should pretend an error happened. */
++	mask = POLLERR /* | POLLIN | POLLOUT */;
++	dentry = file->f_dentry;
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
++	if (unlikely(err))
++		goto out;
++
++	/* it is not an error if h_file has no operation */
++	mask = DEFAULT_POLLMASK;
++	h_file = au_h_fptr(file, au_fbstart(file));
++	if (h_file->f_op && h_file->f_op->poll)
++		mask = h_file->f_op->poll(h_file, wait);
++
++	di_read_unlock(dentry, AuLock_IR);
++	fi_read_unlock(file);
++
++ out:
++	si_read_unlock(sb);
++	AuTraceErr((int)mask);
++	return mask;
++}
++
++static int aufs_fsync_nondir(struct file *file, struct dentry *dentry,
++			     int datasync)
++{
++	int err;
++	struct au_pin pin;
++	struct inode *inode;
++	struct file *h_file;
++	struct super_block *sb;
++
++	inode = dentry->d_inode;
++	IMustLock(file->f_mapping->host);
++	if (inode != file->f_mapping->host) {
++		mutex_unlock(&file->f_mapping->host->i_mutex);
++		mutex_lock(&inode->i_mutex);
++	}
++	IMustLock(inode);
++
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++
++	err = 0; /* -EBADF; */ /* posix? */
++	if (unlikely(!(file->f_mode & FMODE_WRITE)))
++		goto out;
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	err = au_ready_to_write(file, -1, &pin);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err))
++		goto out_unlock;
++	au_unpin(&pin);
++
++	err = -EINVAL;
++	h_file = au_h_fptr(file, au_fbstart(file));
++	if (h_file->f_op && h_file->f_op->fsync) {
++		struct dentry *h_d;
++		struct mutex *h_mtx;
++
++		/*
++		 * no filemap_fdatawrite() since aufs file has no its own
++		 * mapping, but dir.
++		 */
++		h_d = h_file->f_dentry;
++		h_mtx = &h_d->d_inode->i_mutex;
++		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++		err = h_file->f_op->fsync(h_file, h_d, datasync);
++		if (!err)
++			vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL);
++		/*ignore*/
++		au_cpup_attr_timesizes(inode);
++		mutex_unlock(h_mtx);
++	}
++
++ out_unlock:
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++ out:
++	si_read_unlock(sb);
++	if (inode != file->f_mapping->host) {
++		mutex_unlock(&inode->i_mutex);
++		mutex_lock(&file->f_mapping->host->i_mutex);
++	}
++	return err;
++}
++
++static int aufs_fasync(int fd, struct file *file, int flag)
++{
++	int err;
++	struct file *h_file;
++	struct dentry *dentry;
++	struct super_block *sb;
++
++	dentry = file->f_dentry;
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
++	if (unlikely(err))
++		goto out;
++
++	h_file = au_h_fptr(file, au_fbstart(file));
++	if (h_file->f_op && h_file->f_op->fasync)
++		err = h_file->f_op->fasync(fd, h_file, flag);
++
++	di_read_unlock(dentry, AuLock_IR);
++	fi_read_unlock(file);
++
++ out:
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct file_operations aufs_file_fop = {
++	/*
++	 * while generic_file_llseek/_unlocked() don't use BKL,
++	 * don't use it since it operates file->f_mapping->host.
++	 * in aufs, it may be a real file and may confuse users by UDBA.
++	 */
++	/* .llseek		= generic_file_llseek, */
++
++	.read		= aufs_read,
++	.write		= aufs_write,
++	.poll		= aufs_poll,
++	.mmap		= aufs_mmap,
++	.open		= aufs_open_nondir,
++	.flush		= aufs_flush,
++	.release	= aufs_release_nondir,
++	.fsync		= aufs_fsync_nondir,
++	.fasync		= aufs_fasync,
++	.splice_write	= aufs_splice_write,
++	.splice_read	= aufs_splice_read
++};
+diff -uNr test/fs/aufs/file.c aufs2-standalone/fs/aufs/file.c
+--- test/fs/aufs/file.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/file.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,551 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * handling file/dir, and address_space operation
++ */
++
++#include <linux/fsnotify.h>
++#include <linux/pagemap.h>
++#include "aufs.h"
++
++/*
++ * a dirty trick for handling deny_write_access().
++ * because FMODE_EXEC flag is not passed to f_op->open(),
++ * set it to file->private_data temporary.
++ */
++void au_store_oflag(struct nameidata *nd)
++{
++	if (nd
++	    && !(nd->flags & LOOKUP_CONTINUE)
++	    && (nd->flags & LOOKUP_OPEN))
++		nd->intent.open.file->private_data
++			= (void *)nd->intent.open.flags;
++	/* smp_mb(); */
++}
++
++/* drop flags for writing */
++unsigned int au_file_roflags(unsigned int flags)
++{
++	flags &= ~(O_WRONLY | O_RDWR | O_APPEND | O_CREAT | O_TRUNC);
++	flags |= O_RDONLY | O_NOATIME;
++	return flags;
++}
++
++/* common functions to regular file and dir */
++struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
++		       struct file *file)
++{
++	struct file *h_file;
++	struct dentry *h_dentry;
++	struct inode *h_inode;
++	struct super_block *sb;
++	struct au_branch *br;
++	int err;
++
++	h_dentry = au_h_dptr(dentry, bindex);
++	h_inode = h_dentry->d_inode;
++	/* a race condition can happen between open and unlink/rmdir */
++	h_file = ERR_PTR(-ENOENT);
++	if (unlikely((!d_unhashed(dentry) && d_unhashed(h_dentry))
++		     || !h_inode))
++		goto out;
++
++	sb = dentry->d_sb;
++	br = au_sbr(sb, bindex);
++	h_file = ERR_PTR(-EACCES);
++	if (file && (file->f_mode & FMODE_EXEC)
++	    && (br->br_mnt->mnt_flags & MNT_NOEXEC))
++		goto out;
++
++	/* drop flags for writing */
++	if (au_test_ro(sb, bindex, dentry->d_inode))
++		flags = au_file_roflags(flags);
++	flags &= ~O_CREAT;
++	atomic_inc(&br->br_count);
++	h_file = dentry_open(dget(h_dentry), mntget(br->br_mnt), flags);
++	if (IS_ERR(h_file))
++		goto out_br;
++
++	if (file && (file->f_mode & FMODE_EXEC)) {
++		h_file->f_mode |= FMODE_EXEC;
++		err = deny_write_access(h_file);
++		if (unlikely(err)) {
++			fput(h_file);
++			h_file = ERR_PTR(err);
++			goto out_br;
++		}
++	}
++	fsnotify_open(h_dentry);
++	goto out; /* success */
++
++ out_br:
++	atomic_dec(&br->br_count);
++ out:
++	return h_file;
++}
++
++int au_do_open(struct file *file, int (*open)(struct file *file, int flags))
++{
++	int err;
++	struct dentry *dentry;
++	struct super_block *sb;
++
++	dentry = file->f_dentry;
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	err = au_finfo_init(file);
++	if (unlikely(err))
++		goto out;
++
++	di_read_lock_child(dentry, AuLock_IR);
++	err = open(file, file->f_flags);
++	di_read_unlock(dentry, AuLock_IR);
++
++	fi_write_unlock(file);
++	if (unlikely(err))
++		au_finfo_fin(file);
++ out:
++	si_read_unlock(sb);
++	return err;
++}
++
++int au_reopen_nondir(struct file *file)
++{
++	int err;
++	aufs_bindex_t bstart, bindex, bend;
++	struct dentry *dentry;
++	struct file *h_file, *h_file_tmp;
++
++	dentry = file->f_dentry;
++	bstart = au_dbstart(dentry);
++	h_file_tmp = NULL;
++	if (au_fbstart(file) == bstart) {
++		h_file = au_h_fptr(file, bstart);
++		if (file->f_mode == h_file->f_mode)
++			return 0; /* success */
++		h_file_tmp = h_file;
++		get_file(h_file_tmp);
++		au_set_h_fptr(file, bstart, NULL);
++	}
++	AuDebugOn(au_fbstart(file) < bstart
++		  || au_fi(file)->fi_hfile[0 + bstart].hf_file);
++
++	h_file = au_h_open(dentry, bstart, file->f_flags & ~O_TRUNC, file);
++	err = PTR_ERR(h_file);
++	if (IS_ERR(h_file))
++		goto out; /* todo: close all? */
++
++	err = 0;
++	au_set_fbstart(file, bstart);
++	au_set_h_fptr(file, bstart, h_file);
++	au_update_figen(file);
++	/* todo: necessary? */
++	/* file->f_ra = h_file->f_ra; */
++
++	/* close lower files */
++	bend = au_fbend(file);
++	for (bindex = bstart + 1; bindex <= bend; bindex++)
++		au_set_h_fptr(file, bindex, NULL);
++	au_set_fbend(file, bstart);
++
++ out:
++	if (h_file_tmp)
++		fput(h_file_tmp);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_reopen_wh(struct file *file, aufs_bindex_t btgt,
++			struct dentry *hi_wh)
++{
++	int err;
++	aufs_bindex_t bstart;
++	struct au_dinfo *dinfo;
++	struct dentry *h_dentry;
++
++	dinfo = au_di(file->f_dentry);
++	bstart = dinfo->di_bstart;
++	dinfo->di_bstart = btgt;
++	h_dentry = dinfo->di_hdentry[0 + btgt].hd_dentry;
++	dinfo->di_hdentry[0 + btgt].hd_dentry = hi_wh;
++	err = au_reopen_nondir(file);
++	dinfo->di_hdentry[0 + btgt].hd_dentry = h_dentry;
++	dinfo->di_bstart = bstart;
++
++	return err;
++}
++
++static int au_ready_to_write_wh(struct file *file, loff_t len,
++				aufs_bindex_t bcpup)
++{
++	int err;
++	struct inode *inode;
++	struct dentry *dentry, *hi_wh;
++	struct super_block *sb;
++
++	dentry = file->f_dentry;
++	inode = dentry->d_inode;
++	hi_wh = au_hi_wh(inode, bcpup);
++	if (!hi_wh)
++		err = au_sio_cpup_wh(dentry, bcpup, len, file);
++	else
++		/* already copied-up after unlink */
++		err = au_reopen_wh(file, bcpup, hi_wh);
++
++	sb = dentry->d_sb;
++	if (!err && inode->i_nlink > 1 && au_opt_test(au_mntflags(sb), PLINK))
++		au_plink_append(inode, bcpup, au_h_dptr(dentry, bcpup));
++
++	return err;
++}
++
++/*
++ * prepare the @file for writing.
++ */
++int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin)
++{
++	int err;
++	aufs_bindex_t bstart, bcpup;
++	struct dentry *dentry, *parent, *h_dentry;
++	struct inode *h_inode, *inode;
++	struct super_block *sb;
++
++	dentry = file->f_dentry;
++	sb = dentry->d_sb;
++	bstart = au_fbstart(file);
++	inode = dentry->d_inode;
++	err = au_test_ro(sb, bstart, inode);
++	if (!err && (au_h_fptr(file, bstart)->f_mode & FMODE_WRITE)) {
++		err = au_pin(pin, dentry, bstart, AuOpt_UDBA_NONE, /*flags*/0);
++		goto out;
++	}
++
++	/* need to cpup */
++	parent = dget_parent(dentry);
++	di_write_lock_parent(parent);
++	err = AuWbrCopyup(au_sbi(sb), dentry);
++	bcpup = err;
++	if (unlikely(err < 0))
++		goto out_dgrade;
++	err = 0;
++
++	if (!au_h_dptr(parent, bcpup)) {
++		err = au_cpup_dirs(dentry, bcpup);
++		if (unlikely(err))
++			goto out_dgrade;
++	}
++
++	err = au_pin(pin, dentry, bcpup, AuOpt_UDBA_NONE,
++		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++	if (unlikely(err))
++		goto out_dgrade;
++
++	h_dentry = au_h_fptr(file, bstart)->f_dentry;
++	h_inode = h_dentry->d_inode;
++	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++	if (d_unhashed(dentry) /* || d_unhashed(h_dentry) */
++	    /* || !h_inode->i_nlink */) {
++		err = au_ready_to_write_wh(file, len, bcpup);
++		di_downgrade_lock(parent, AuLock_IR);
++	} else {
++		di_downgrade_lock(parent, AuLock_IR);
++		if (!au_h_dptr(dentry, bcpup))
++			err = au_sio_cpup_simple(dentry, bcpup, len,
++						 AuCpup_DTIME);
++		if (!err)
++			err = au_reopen_nondir(file);
++	}
++	mutex_unlock(&h_inode->i_mutex);
++
++	if (!err) {
++		au_pin_set_parent_lflag(pin, /*lflag*/0);
++		goto out_dput; /* success */
++	}
++	au_unpin(pin);
++	goto out_unlock;
++
++ out_dgrade:
++	di_downgrade_lock(parent, AuLock_IR);
++ out_unlock:
++	di_read_unlock(parent, AuLock_IR);
++ out_dput:
++	dput(parent);
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_file_refresh_by_inode(struct file *file, int *need_reopen)
++{
++	int err;
++	aufs_bindex_t bstart;
++	struct au_pin pin;
++	struct au_finfo *finfo;
++	struct dentry *dentry, *parent, *hi_wh;
++	struct inode *inode;
++	struct super_block *sb;
++
++	err = 0;
++	finfo = au_fi(file);
++	dentry = file->f_dentry;
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	bstart = au_ibstart(inode);
++	if (bstart == finfo->fi_bstart)
++		goto out;
++
++	parent = dget_parent(dentry);
++	if (au_test_ro(sb, bstart, inode)) {
++		di_read_lock_parent(parent, !AuLock_IR);
++		err = AuWbrCopyup(au_sbi(sb), dentry);
++		bstart = err;
++		di_read_unlock(parent, !AuLock_IR);
++		if (unlikely(err < 0))
++			goto out_parent;
++		err = 0;
++	}
++
++	di_read_lock_parent(parent, AuLock_IR);
++	hi_wh = au_hi_wh(inode, bstart);
++	if (au_opt_test(au_mntflags(sb), PLINK)
++	    && au_plink_test(inode)
++	    && !d_unhashed(dentry)) {
++		err = au_test_and_cpup_dirs(dentry, bstart);
++		if (unlikely(err))
++			goto out_unlock;
++
++		/* always superio. */
++		err = au_pin(&pin, dentry, bstart, AuOpt_UDBA_NONE,
++			     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++		if (!err)
++			err = au_sio_cpup_simple(dentry, bstart, -1,
++						 AuCpup_DTIME);
++		au_unpin(&pin);
++	} else if (hi_wh) {
++		/* already copied-up after unlink */
++		err = au_reopen_wh(file, bstart, hi_wh);
++		*need_reopen = 0;
++	}
++
++ out_unlock:
++	di_read_unlock(parent, AuLock_IR);
++ out_parent:
++	dput(parent);
++ out:
++	return err;
++}
++
++static void au_do_refresh_file(struct file *file)
++{
++	aufs_bindex_t bindex, bend, new_bindex, brid;
++	struct au_hfile *p, tmp, *q;
++	struct au_finfo *finfo;
++	struct super_block *sb;
++
++	sb = file->f_dentry->d_sb;
++	finfo = au_fi(file);
++	p = finfo->fi_hfile + finfo->fi_bstart;
++	brid = p->hf_br->br_id;
++	bend = finfo->fi_bend;
++	for (bindex = finfo->fi_bstart; bindex <= bend; bindex++, p++) {
++		if (!p->hf_file)
++			continue;
++
++		new_bindex = au_br_index(sb, p->hf_br->br_id);
++		if (new_bindex == bindex)
++			continue;
++		if (new_bindex < 0) {
++			au_set_h_fptr(file, bindex, NULL);
++			continue;
++		}
++
++		/* swap two lower inode, and loop again */
++		q = finfo->fi_hfile + new_bindex;
++		tmp = *q;
++		*q = *p;
++		*p = tmp;
++		if (tmp.hf_file) {
++			bindex--;
++			p--;
++		}
++	}
++
++	p = finfo->fi_hfile;
++	if (!au_test_mmapped(file) && !d_unhashed(file->f_dentry)) {
++		bend = au_sbend(sb);
++		for (finfo->fi_bstart = 0; finfo->fi_bstart <= bend;
++		     finfo->fi_bstart++, p++)
++			if (p->hf_file) {
++				if (p->hf_file->f_dentry
++				    && p->hf_file->f_dentry->d_inode)
++					break;
++				else
++					au_hfput(p, file);
++			}
++	} else {
++		bend = au_br_index(sb, brid);
++		for (finfo->fi_bstart = 0; finfo->fi_bstart < bend;
++		     finfo->fi_bstart++, p++)
++			if (p->hf_file)
++				au_hfput(p, file);
++		bend = au_sbend(sb);
++	}
++
++	p = finfo->fi_hfile + bend;
++	for (finfo->fi_bend = bend; finfo->fi_bend >= finfo->fi_bstart;
++	     finfo->fi_bend--, p--)
++		if (p->hf_file) {
++			if (p->hf_file->f_dentry
++			    && p->hf_file->f_dentry->d_inode)
++				break;
++			else
++				au_hfput(p, file);
++		}
++	AuDebugOn(finfo->fi_bend < finfo->fi_bstart);
++}
++
++/*
++ * after branch manipulating, refresh the file.
++ */
++static int refresh_file(struct file *file, int (*reopen)(struct file *file))
++{
++	int err, need_reopen;
++	struct dentry *dentry;
++	aufs_bindex_t bend, bindex;
++
++	dentry = file->f_dentry;
++	err = au_fi_realloc(au_fi(file), au_sbend(dentry->d_sb) + 1);
++	if (unlikely(err))
++		goto out;
++	au_do_refresh_file(file);
++
++	err = 0;
++	need_reopen = 1;
++	if (!au_test_mmapped(file))
++		err = au_file_refresh_by_inode(file, &need_reopen);
++	if (!err && need_reopen && !d_unhashed(dentry))
++		err = reopen(file);
++	if (!err) {
++		au_update_figen(file);
++		return 0; /* success */
++	}
++
++	/* error, close all lower files */
++	bend = au_fbend(file);
++	for (bindex = au_fbstart(file); bindex <= bend; bindex++)
++		au_set_h_fptr(file, bindex, NULL);
++
++ out:
++	return err;
++}
++
++/* common function to regular file and dir */
++int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
++			  int wlock)
++{
++	int err;
++	unsigned int sigen, figen;
++	aufs_bindex_t bstart;
++	unsigned char pseudo_link;
++	struct dentry *dentry;
++
++	err = 0;
++	dentry = file->f_dentry;
++	sigen = au_sigen(dentry->d_sb);
++	fi_write_lock(file);
++	figen = au_figen(file);
++	di_write_lock_child(dentry);
++	bstart = au_dbstart(dentry);
++	pseudo_link = (bstart != au_ibstart(dentry->d_inode));
++	if (sigen == figen && !pseudo_link && au_fbstart(file) == bstart) {
++		if (!wlock) {
++			di_downgrade_lock(dentry, AuLock_IR);
++			fi_downgrade_lock(file);
++		}
++		goto out; /* success */
++	}
++
++	AuDbg("sigen %d, figen %d\n", sigen, figen);
++	if (sigen != au_digen(dentry)
++	    || sigen != au_iigen(dentry->d_inode)) {
++		err = au_reval_dpath(dentry, sigen);
++		if (unlikely(err < 0))
++			goto out;
++		AuDebugOn(au_digen(dentry) != sigen
++			  || au_iigen(dentry->d_inode) != sigen);
++	}
++
++	err = refresh_file(file, reopen);
++	if (!err) {
++		if (!wlock) {
++			di_downgrade_lock(dentry, AuLock_IR);
++			fi_downgrade_lock(file);
++		}
++	} else {
++		di_write_unlock(dentry);
++		fi_write_unlock(file);
++	}
++
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* cf. aufs_nopage() */
++/* for madvise(2) */
++static int aufs_readpage(struct file *file __maybe_unused, struct page *page)
++{
++	unlock_page(page);
++	return 0;
++}
++
++/* they will never be called. */
++#ifdef CONFIG_AUFS_DEBUG
++static int aufs_write_begin(struct file *file, struct address_space *mapping,
++			    loff_t pos, unsigned len, unsigned flags,
++			    struct page **pagep, void **fsdata)
++{ AuUnsupport(); return 0; }
++static int aufs_write_end(struct file *file, struct address_space *mapping,
++			  loff_t pos, unsigned len, unsigned copied,
++			  struct page *page, void *fsdata)
++{ AuUnsupport(); return 0; }
++static int aufs_writepage(struct page *page, struct writeback_control *wbc)
++{ AuUnsupport(); return 0; }
++static void aufs_sync_page(struct page *page)
++{ AuUnsupport(); }
++
++static int aufs_set_page_dirty(struct page *page)
++{ AuUnsupport(); return 0; }
++static void aufs_invalidatepage(struct page *page, unsigned long offset)
++{ AuUnsupport(); }
++static int aufs_releasepage(struct page *page, gfp_t gfp)
++{ AuUnsupport(); return 0; }
++static ssize_t aufs_direct_IO(int rw, struct kiocb *iocb,
++			      const struct iovec *iov, loff_t offset,
++			      unsigned long nr_segs)
++{ AuUnsupport(); return 0; }
++#endif /* CONFIG_AUFS_DEBUG */
++
++struct address_space_operations aufs_aop = {
++	.readpage	= aufs_readpage,
++#ifdef CONFIG_AUFS_DEBUG
++	.writepage	= aufs_writepage,
++	.sync_page	= aufs_sync_page,
++	.set_page_dirty	= aufs_set_page_dirty,
++	.write_begin	= aufs_write_begin,
++	.write_end	= aufs_write_end,
++	.invalidatepage	= aufs_invalidatepage,
++	.releasepage	= aufs_releasepage,
++	.direct_IO	= aufs_direct_IO,
++#endif /* CONFIG_AUFS_DEBUG */
++};
+diff -uNr test/fs/aufs/file.h aufs2-standalone/fs/aufs/file.h
+--- test/fs/aufs/file.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/file.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,148 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * file operations
++ */
++
++#ifndef __AUFS_FILE_H__
++#define __AUFS_FILE_H__
++
++#ifdef __KERNEL__
++
++#include <linux/file.h>
++#include <linux/fs.h>
++#include <linux/aufs_type.h>
++#include "rwsem.h"
++
++struct au_branch;
++struct au_hfile {
++	struct file		*hf_file;
++	struct au_branch	*hf_br;
++};
++
++struct au_vdir;
++struct au_finfo {
++	atomic_t		fi_generation;
++
++	struct rw_semaphore	fi_rwsem;
++	struct au_hfile		*fi_hfile;
++	aufs_bindex_t		fi_bstart, fi_bend;
++
++	union {
++		/* non-dir only */
++		struct vm_operations_struct	*fi_h_vm_ops;
++
++		/* dir only */
++		struct {
++			struct au_vdir		*fi_vdir_cache;
++			int			fi_maintain_plink;
++		};
++	};
++};
++
++/* ---------------------------------------------------------------------- */
++
++/* file.c */
++extern struct address_space_operations aufs_aop;
++void au_store_oflag(struct nameidata *nd);
++unsigned int au_file_roflags(unsigned int flags);
++struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
++		       struct file *file);
++int au_do_open(struct file *file, int (*open)(struct file *file, int flags));
++int au_reopen_nondir(struct file *file);
++struct au_pin;
++int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin);
++int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
++			  int wlock);
++
++/* f_op.c */
++extern struct file_operations aufs_file_fop;
++int aufs_flush(struct file *file, fl_owner_t id);
++
++/* finfo.c */
++void au_hfput(struct au_hfile *hf, struct file *file);
++void au_set_h_fptr(struct file *file, aufs_bindex_t bindex,
++		   struct file *h_file);
++
++void au_update_figen(struct file *file);
++
++void au_finfo_fin(struct file *file);
++int au_finfo_init(struct file *file);
++int au_fi_realloc(struct au_finfo *finfo, int nbr);
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct au_finfo *au_fi(struct file *file)
++{
++	return file->private_data;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * fi_read_lock, fi_write_lock,
++ * fi_read_unlock, fi_write_unlock, fi_downgrade_lock
++ */
++AuSimpleRwsemFuncs(fi, struct file *f, &au_fi(f)->fi_rwsem);
++
++#define FiMustNoWaiters(f)	AuRwMustNoWaiters(&au_fi(f)->fi_rwsem)
++
++/* ---------------------------------------------------------------------- */
++
++/* todo: hard/soft set? */
++static inline aufs_bindex_t au_fbstart(struct file *file)
++{
++	return au_fi(file)->fi_bstart;
++}
++
++static inline aufs_bindex_t au_fbend(struct file *file)
++{
++	return au_fi(file)->fi_bend;
++}
++
++static inline struct au_vdir *au_fvdir_cache(struct file *file)
++{
++	return au_fi(file)->fi_vdir_cache;
++}
++
++static inline void au_set_fbstart(struct file *file, aufs_bindex_t bindex)
++{
++	au_fi(file)->fi_bstart = bindex;
++}
++
++static inline void au_set_fbend(struct file *file, aufs_bindex_t bindex)
++{
++	au_fi(file)->fi_bend = bindex;
++}
++
++static inline void au_set_fvdir_cache(struct file *file,
++				      struct au_vdir *vdir_cache)
++{
++	au_fi(file)->fi_vdir_cache = vdir_cache;
++}
++
++static inline struct file *au_h_fptr(struct file *file, aufs_bindex_t bindex)
++{
++	return au_fi(file)->fi_hfile[0 + bindex].hf_file;
++}
++
++/* todo: memory barrier? */
++static inline unsigned int au_figen(struct file *f)
++{
++	return atomic_read(&au_fi(f)->fi_generation);
++}
++
++static inline int au_test_mmapped(struct file *f)
++{
++	return !!(au_fi(f)->fi_h_vm_ops);
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_FILE_H__ */
+diff -uNr test/fs/aufs/finfo.c aufs2-standalone/fs/aufs/finfo.c
+--- test/fs/aufs/finfo.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/finfo.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,126 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * file private data
++ */
++
++#include "aufs.h"
++
++void au_hfput(struct au_hfile *hf, struct file *file)
++{
++	if (file->f_mode & FMODE_EXEC)
++		allow_write_access(hf->hf_file);
++	fput(hf->hf_file);
++	hf->hf_file = NULL;
++	atomic_dec(&hf->hf_br->br_count);
++	hf->hf_br = NULL;
++}
++
++void au_set_h_fptr(struct file *file, aufs_bindex_t bindex, struct file *val)
++{
++	struct au_finfo *finfo = au_fi(file);
++	struct au_hfile *hf;
++
++	hf = finfo->fi_hfile + bindex;
++	if (hf->hf_file)
++		au_hfput(hf, file);
++	if (val) {
++		hf->hf_file = val;
++		hf->hf_br = au_sbr(file->f_dentry->d_sb, bindex);
++	}
++}
++
++void au_update_figen(struct file *file)
++{
++	atomic_set(&au_fi(file)->fi_generation, au_digen(file->f_dentry));
++	/* smp_mb(); */ /* atomic_set */
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_finfo_fin(struct file *file)
++{
++	struct au_finfo *finfo;
++	aufs_bindex_t bindex, bend;
++
++	fi_write_lock(file);
++	bend = au_fbend(file);
++	bindex = au_fbstart(file);
++	if (bindex >= 0)
++		/*
++		 * calls fput() instead of filp_close(),
++		 * since no dnotify or lock for the lower file.
++		 */
++		for (; bindex <= bend; bindex++)
++			au_set_h_fptr(file, bindex, NULL);
++
++	finfo = au_fi(file);
++	au_dbg_verify_hf(finfo);
++	kfree(finfo->fi_hfile);
++	fi_write_unlock(file);
++	au_rwsem_destroy(&finfo->fi_rwsem);
++	au_cache_free_finfo(finfo);
++}
++
++int au_finfo_init(struct file *file)
++{
++	struct au_finfo *finfo;
++	struct dentry *dentry;
++	union {
++		unsigned int u;
++		fmode_t m;
++	} u;
++
++	dentry = file->f_dentry;
++	finfo = au_cache_alloc_finfo();
++	if (unlikely(!finfo))
++		goto out;
++
++	finfo->fi_hfile = kcalloc(au_sbend(dentry->d_sb) + 1,
++				  sizeof(*finfo->fi_hfile), GFP_NOFS);
++	if (unlikely(!finfo->fi_hfile))
++		goto out_finfo;
++
++	init_rwsem(&finfo->fi_rwsem);
++	down_write(&finfo->fi_rwsem);
++	finfo->fi_bstart = -1;
++	finfo->fi_bend = -1;
++	atomic_set(&finfo->fi_generation, au_digen(dentry));
++	/* smp_mb(); */ /* atomic_set */
++
++	/* cf. au_store_oflag() */
++	u.u = (unsigned int)file->private_data;
++	file->f_mode |= (u.m & FMODE_EXEC);
++	file->private_data = finfo;
++	return 0; /* success */
++
++ out_finfo:
++	au_cache_free_finfo(finfo);
++ out:
++	return -ENOMEM;
++}
++
++int au_fi_realloc(struct au_finfo *finfo, int nbr)
++{
++	int err, sz;
++	struct au_hfile *hfp;
++
++	err = -ENOMEM;
++	sz = sizeof(*hfp) * (finfo->fi_bend + 1);
++	if (!sz)
++		sz = sizeof(*hfp);
++	hfp = au_kzrealloc(finfo->fi_hfile, sz, sizeof(*hfp) * nbr, GFP_NOFS);
++	if (hfp) {
++		finfo->fi_hfile = hfp;
++		err = 0;
++	}
++
++	return err;
++}
+diff -uNr test/fs/aufs/fstype.h aufs2-standalone/fs/aufs/fstype.h
+--- test/fs/aufs/fstype.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/fstype.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,404 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * judging filesystem type
++ */
++
++#ifndef __AUFS_FSTYPE_H__
++#define __AUFS_FSTYPE_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/cramfs_fs.h>
++#include <linux/magic.h>
++#include <linux/romfs_fs.h>
++#include <linux/aufs_type.h>
++
++static inline int au_test_aufs(struct super_block *sb)
++{
++	return sb->s_magic == AUFS_SUPER_MAGIC;
++}
++
++static inline const char *au_sbtype(struct super_block *sb)
++{
++	return sb->s_type->name;
++}
++
++static inline int au_test_iso9660(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_ROMFS_FS) || defined(CONFIG_ROMFS_FS_MODULE)
++	return sb->s_magic == ROMFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_romfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_ISO9660_FS) || defined(CONFIG_ISO9660_FS_MODULE)
++	return sb->s_magic == ISOFS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_cramfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_CRAMFS) || defined(CONFIG_CRAMFS_MODULE)
++	return sb->s_magic == CRAMFS_MAGIC;
++#endif
++	return 0;
++}
++
++static inline int au_test_nfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_NFS_FS) || defined(CONFIG_NFS_FS_MODULE)
++	return sb->s_magic == NFS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_fuse(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_FUSE_FS) || defined(CONFIG_FUSE_FS_MODULE)
++	return sb->s_magic == FUSE_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_xfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_XFS_FS) || defined(CONFIG_XFS_FS_MODULE)
++	return sb->s_magic == XFS_SB_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_tmpfs(struct super_block *sb __maybe_unused)
++{
++#ifdef CONFIG_TMPFS
++	return sb->s_magic == TMPFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_ecryptfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_ECRYPT_FS) || defined(CONFIG_ECRYPT_FS_MODULE)
++	return !strcmp(au_sbtype(sb), "ecryptfs");
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_smbfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_SMB_FS) || defined(CONFIG_SMB_FS_MODULE)
++	return sb->s_magic == SMB_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_ocfs2(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_OCFS2_FS) || defined(CONFIG_OCFS2_FS_MODULE)
++	return sb->s_magic == OCFS2_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_ocfs2_dlmfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_OCFS2_FS_O2CB) || defined(CONFIG_OCFS2_FS_O2CB_MODULE)
++	return sb->s_magic == DLMFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_coda(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_CODA_FS) || defined(CONFIG_CODA_FS_MODULE)
++	return sb->s_magic == CODA_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_v9fs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_9P_FS) || defined(CONFIG_9P_FS_MODULE)
++	return sb->s_magic == V9FS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_ext4(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_EXT4DEV_FS) || defined(CONFIG_EXT4DEV_FS_MODULE)
++	return sb->s_magic == EXT4_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_sysv(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_SYSV_FS) || defined(CONFIG_SYSV_FS_MODULE)
++	return !strcmp(au_sbtype(sb), "sysv");
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_ramfs(struct super_block *sb)
++{
++	return sb->s_magic == RAMFS_MAGIC;
++}
++
++static inline int au_test_ubifs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_UBIFS_FS) || defined(CONFIG_UBIFS_FS_MODULE)
++	return sb->s_magic == UBIFS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_procfs(struct super_block *sb __maybe_unused)
++{
++#ifdef CONFIG_PROC_FS
++	return sb->s_magic == PROC_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_sysfs(struct super_block *sb __maybe_unused)
++{
++#ifdef CONFIG_SYSFS
++	return sb->s_magic == SYSFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_configfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_CONFIGFS_FS) || defined(CONFIG_CONFIGFS_FS_MODULE)
++	return sb->s_magic == CONFIGFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_minix(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_MINIX_FS) || defined(CONFIG_MINIX_FS_MODULE)
++	return sb->s_magic == MINIX3_SUPER_MAGIC
++		|| sb->s_magic == MINIX2_SUPER_MAGIC
++		|| sb->s_magic == MINIX2_SUPER_MAGIC2
++		|| sb->s_magic == MINIX_SUPER_MAGIC
++		|| sb->s_magic == MINIX_SUPER_MAGIC2;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_cifs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_CIFS_FS) || defined(CONFIGCIFS_FS_MODULE)
++	return sb->s_magic == CIFS_MAGIC_NUMBER;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_fat(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_FAT_FS) || defined(CONFIG_FAT_FS_MODULE)
++	return sb->s_magic == MSDOS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_msdos(struct super_block *sb)
++{
++	return au_test_fat(sb);
++}
++
++static inline int au_test_vfat(struct super_block *sb)
++{
++	return au_test_fat(sb);
++}
++
++static inline int au_test_securityfs(struct super_block *sb __maybe_unused)
++{
++#ifdef CONFIG_SECURITYFS
++	return sb->s_magic == SECURITYFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++/* ---------------------------------------------------------------------- */
++/*
++ * they can't be an aufs branch.
++ */
++static inline int au_test_fs_unsuppoted(struct super_block *sb)
++{
++	return au_test_procfs(sb)
++		|| au_test_sysfs(sb)
++		|| au_test_configfs(sb)
++		|| au_test_securityfs(sb)
++		|| au_test_ramfs(sb)
++		/* || !strcmp(au_sbtype(sb), "unionfs") */
++		|| au_test_aufs(sb); /* will be supported in next version */
++}
++
++/*
++ * If the filesystem supports NFS-export, then it has to support NULL as
++ * a nameidata parameter for ->create(), ->lookup() and ->d_revalidate().
++ * We can apply this principle when we handle a lower filesystem.
++ */
++static inline int au_test_fs_null_nd(struct super_block *sb)
++{
++	return !!sb->s_export_op;
++}
++
++static inline int au_test_fs_remote(struct super_block *sb)
++{
++	return !au_test_tmpfs(sb)
++		&& !(sb->s_type->fs_flags & FS_REQUIRES_DEV);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * Note: these functions (below) are created after reading ->getattr() in all
++ * filesystems under linux/fs. it means we have to do so in every update...
++ */
++
++/*
++ * some filesystems require getattr to refresh the inode attributes before
++ * referencing.
++ * in most cases, we can rely on the inode attribute in NFS (or every remote fs)
++ * and leave the work for d_revalidate()
++ */
++static inline int au_test_fs_refresh_iattr(struct super_block *sb)
++{
++	return au_test_nfs(sb)
++		|| au_test_fuse(sb)
++		/* || au_test_smbfs(sb) */	/* untested */
++		/* || au_test_ocfs2(sb) */	/* untested */
++		/* || au_test_coda(sb) */	/* untested */
++		/* || au_test_v9fs(sb) */	/* untested */
++		;
++}
++
++/*
++ * filesystems which don't maintain i_size or i_blocks.
++ */
++static inline int au_test_fs_bad_iattr_size(struct super_block *sb)
++{
++	return au_test_xfs(sb)
++		/* || au_test_ext4(sb) */	/* untested */
++		/* || au_test_ocfs2(sb) */	/* untested */
++		/* || au_test_ocfs2_dlmfs(sb) */ /* untested */
++		/* || au_test_sysv(sb) */	/* untested */
++		/* || au_test_ramfs(sb)*/	/* unsupported */
++		/* || au_test_ubifs(sb) */	/* untested */
++		/* || au_test_minix(sb) */	/* untested */
++		;
++}
++
++/*
++ * filesystems which don't store the correct value in some of their inode
++ * attributes.
++ */
++static inline int au_test_fs_bad_iattr(struct super_block *sb)
++{
++	return au_test_fs_bad_iattr_size(sb)
++		/* || au_test_cifs(sb) */	/* untested */
++		|| au_test_fat(sb)
++		|| au_test_msdos(sb)
++		|| au_test_vfat(sb);
++}
++
++/*
++ * filesystems which sets S_NOATIME and S_NOCMTIME.
++ */
++static inline int au_test_fs_notime(struct super_block *sb)
++{
++	return au_test_nfs(sb)
++		|| au_test_fuse(sb)
++		/* || au_test_cifs(sb) */	/* untested */
++		/* || au_test_ubifs(sb) */	/* untested */
++		;
++}
++
++/*
++ * filesystems which requires replacing i_mapping.
++ */
++static inline int au_test_fs_bad_mapping(struct super_block *sb)
++{
++	return au_test_fuse(sb);
++}
++
++/* temporary support for i#1 in cramfs */
++static inline int au_test_fs_unique_ino(struct inode *inode)
++{
++	if (au_test_cramfs(inode->i_sb))
++		return inode->i_ino != 1;
++	return 1;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * the filesystem where the xino files placed must support i/o after unlink and
++ * maintain i_size and i_blocks.
++ */
++static inline int au_test_fs_bad_xino(struct super_block *sb)
++{
++	return au_test_fs_remote(sb)
++		|| au_test_fs_bad_iattr_size(sb)
++		|| !au_test_fs_null_nd(sb) /* to keep xino code simple */
++		/* don't want unnecessary work for xino */
++		|| au_test_aufs(sb)
++		|| au_test_ecryptfs(sb);
++}
++
++static inline int au_test_fs_trunc_xino(struct super_block *sb)
++{
++	return au_test_tmpfs(sb);
++}
++
++/*
++ * test if the @sb is real-readonly.
++ */
++static inline int au_test_fs_rr(struct super_block *sb)
++{
++	return au_test_iso9660(sb)
++		|| au_test_cramfs(sb)
++		|| au_test_romfs(sb);
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_FSTYPE_H__ */
+diff -uNr test/fs/aufs/hinotify.c aufs2-standalone/fs/aufs/hinotify.c
+--- test/fs/aufs/hinotify.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/hinotify.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,746 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * inotify for the lower directories
++ */
++
++#include "aufs.h"
++
++static const __u32 AuHinMask = (IN_MOVE | IN_DELETE | IN_CREATE);
++static struct inotify_handle *au_hin_handle;
++
++AuCacheFuncs(hinotify, HINOTIFY);
++
++int au_hin_alloc(struct au_hinode *hinode, struct inode *inode,
++		 struct inode *h_inode)
++{
++	int err;
++	struct au_hinotify *hin;
++	s32 wd;
++
++	err = -ENOMEM;
++	hin = au_cache_alloc_hinotify();
++	if (hin) {
++		AuDebugOn(hinode->hi_notify);
++		hinode->hi_notify = hin;
++		hin->hin_aufs_inode = inode;
++
++		inotify_init_watch(&hin->hin_watch);
++		wd = inotify_add_watch(au_hin_handle, &hin->hin_watch, h_inode,
++				       AuHinMask);
++		if (wd >= 0)
++			return 0; /* success */
++
++		err = wd;
++		put_inotify_watch(&hin->hin_watch);
++		au_cache_free_hinotify(hin);
++		hinode->hi_notify = NULL;
++	}
++
++	return err;
++}
++
++void au_hin_free(struct au_hinode *hinode)
++{
++	int err;
++	struct au_hinotify *hin;
++
++	hin = hinode->hi_notify;
++	if (hin) {
++		err = 0;
++		if (atomic_read(&hin->hin_watch.count))
++			err = inotify_rm_watch(au_hin_handle, &hin->hin_watch);
++		if (unlikely(err))
++			/* it means the watch is already removed */
++			AuWarn("failed inotify_rm_watch() %d\n", err);
++		au_cache_free_hinotify(hin);
++		hinode->hi_notify = NULL;
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_hin_ctl(struct au_hinode *hinode, int do_set)
++{
++	struct inode *h_inode;
++	struct inotify_watch *watch;
++
++	if (!hinode->hi_notify)
++		return;
++
++	h_inode = hinode->hi_inode;
++	IMustLock(h_inode);
++
++	/* todo: try inotify_find_update_watch()? */
++	watch = &hinode->hi_notify->hin_watch;
++	mutex_lock(&h_inode->inotify_mutex);
++	/* mutex_lock(&watch->ih->mutex); */
++	if (do_set) {
++		AuDebugOn(watch->mask & AuHinMask);
++		watch->mask |= AuHinMask;
++	} else {
++		AuDebugOn(!(watch->mask & AuHinMask));
++		watch->mask &= ~AuHinMask;
++	}
++	/* mutex_unlock(&watch->ih->mutex); */
++	mutex_unlock(&h_inode->inotify_mutex);
++}
++
++void au_reset_hinotify(struct inode *inode, unsigned int flags)
++{
++	aufs_bindex_t bindex, bend;
++	struct inode *hi;
++	struct dentry *iwhdentry;
++
++	bend = au_ibend(inode);
++	for (bindex = au_ibstart(inode); bindex <= bend; bindex++) {
++		hi = au_h_iptr(inode, bindex);
++		if (!hi)
++			continue;
++
++		/* mutex_lock_nested(&hi->i_mutex, AuLsc_I_CHILD); */
++		iwhdentry = au_hi_wh(inode, bindex);
++		if (iwhdentry)
++			dget(iwhdentry);
++		au_igrab(hi);
++		au_set_h_iptr(inode, bindex, NULL, 0);
++		au_set_h_iptr(inode, bindex, au_igrab(hi),
++			      flags & ~AuHi_XINO);
++		iput(hi);
++		dput(iwhdentry);
++		/* mutex_unlock(&hi->i_mutex); */
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int hin_xino(struct inode *inode, struct inode *h_inode)
++{
++	int err;
++	aufs_bindex_t bindex, bend, bfound, bstart;
++	struct inode *h_i;
++
++	err = 0;
++	if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
++		AuWarn("branch root dir was changed\n");
++		goto out;
++	}
++
++	bfound = -1;
++	bend = au_ibend(inode);
++	bstart = au_ibstart(inode);
++#if 0 /* reserved for future use */
++	if (bindex == bend) {
++		/* keep this ino in rename case */
++		goto out;
++	}
++#endif
++	for (bindex = bstart; bindex <= bend; bindex++) {
++		if (au_h_iptr(inode, bindex) == h_inode) {
++			bfound = bindex;
++			break;
++		}
++	}
++	if (bfound < 0)
++		goto out;
++
++	for (bindex = bstart; bindex <= bend; bindex++) {
++		h_i = au_h_iptr(inode, bindex);
++		if (!h_i)
++			continue;
++
++		err = au_xino_write0(inode->i_sb, bindex, h_i->i_ino, 0);
++		/* ignore this error */
++		/* bad action? */
++	}
++
++	/* children inode number will be broken */
++
++ out:
++	AuTraceErr(err);
++	return err;
++}
++
++static int hin_gen_tree(struct dentry *dentry)
++{
++	int err, i, j, ndentry;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry **dentries;
++
++	err = au_dpages_init(&dpages, GFP_NOFS);
++	if (unlikely(err))
++		goto out;
++	err = au_dcsub_pages(&dpages, dentry, NULL, NULL);
++	if (unlikely(err))
++		goto out_dpages;
++
++	for (i = 0; i < dpages.ndpage; i++) {
++		dpage = dpages.dpages + i;
++		dentries = dpage->dentries;
++		ndentry = dpage->ndentry;
++		for (j = 0; j < ndentry; j++) {
++			struct dentry *d;
++
++			d = dentries[j];
++			if (IS_ROOT(d))
++				continue;
++
++			d_drop(d);
++			au_digen_dec(d);
++			if (d->d_inode)
++				/* todo: reset children xino?
++				   cached children only? */
++				au_iigen_dec(d->d_inode);
++		}
++	}
++
++ out_dpages:
++	au_dpages_free(&dpages);
++
++	/* discard children */
++	dentry_unhash(dentry);
++	dput(dentry);
++ out:
++	return err;
++}
++
++/*
++ * return 0 if processed.
++ */
++static int hin_gen_by_inode(char *name, unsigned int nlen, struct inode *inode,
++			    const unsigned int isdir)
++{
++	int err;
++	struct dentry *d;
++	struct qstr *dname;
++
++	err = 1;
++	if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
++		AuWarn("branch root dir was changed\n");
++		err = 0;
++		goto out;
++	}
++
++	if (!isdir) {
++		AuDebugOn(!name);
++		au_iigen_dec(inode);
++		spin_lock(&dcache_lock);
++		list_for_each_entry(d, &inode->i_dentry, d_alias) {
++			dname = &d->d_name;
++			if (dname->len != nlen
++			    && memcmp(dname->name, name, nlen))
++				continue;
++			err = 0;
++			spin_lock(&d->d_lock);
++			__d_drop(d);
++			au_digen_dec(d);
++			spin_unlock(&d->d_lock);
++			break;
++		}
++		spin_unlock(&dcache_lock);
++	} else {
++		au_fset_si(au_sbi(inode->i_sb), FAILED_REFRESH_DIRS);
++		d = d_find_alias(inode);
++		if (!d) {
++			au_iigen_dec(inode);
++			goto out;
++		}
++
++		dname = &d->d_name;
++		if (dname->len == nlen && !memcmp(dname->name, name, nlen))
++			err = hin_gen_tree(d);
++		dput(d);
++	}
++
++ out:
++	AuTraceErr(err);
++	return err;
++}
++
++static int hin_gen_by_name(struct dentry *dentry, const unsigned int isdir)
++{
++	int err;
++	struct inode *inode;
++
++	inode = dentry->d_inode;
++	if (IS_ROOT(dentry)
++	    /* || (inode && inode->i_ino == AUFS_ROOT_INO) */
++		) {
++		AuWarn("branch root dir was changed\n");
++		return 0;
++	}
++
++	err = 0;
++	if (!isdir) {
++		d_drop(dentry);
++		au_digen_dec(dentry);
++		if (inode)
++			au_iigen_dec(inode);
++	} else {
++		au_fset_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIRS);
++		if (inode)
++			err = hin_gen_tree(dentry);
++	}
++
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* hinotify job flags */
++#define AuHinJob_XINO0		1
++#define AuHinJob_GEN		(1 << 1)
++#define AuHinJob_DIRENT		(1 << 2)
++#define AuHinJob_ISDIR		(1 << 3)
++#define AuHinJob_TRYXINO0	(1 << 4)
++#define AuHinJob_MNTPNT		(1 << 5)
++#define au_ftest_hinjob(flags, name)	((flags) & AuHinJob_##name)
++#define au_fset_hinjob(flags, name)	{ (flags) |= AuHinJob_##name; }
++#define au_fclr_hinjob(flags, name)	{ (flags) &= ~AuHinJob_##name; }
++
++struct hin_job_args {
++	unsigned int flags;
++	struct inode *inode, *h_inode, *dir, *h_dir;
++	struct dentry *dentry;
++	char *h_name;
++	int h_nlen;
++};
++
++static int hin_job(struct hin_job_args *a)
++{
++	const unsigned int isdir = au_ftest_hinjob(a->flags, ISDIR);
++
++	/* reset xino */
++	if (au_ftest_hinjob(a->flags, XINO0) && a->inode)
++		hin_xino(a->inode, a->h_inode); /* ignore this error */
++
++	if (au_ftest_hinjob(a->flags, TRYXINO0)
++	    && a->inode
++	    && a->h_inode) {
++		mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
++		if (!a->h_inode->i_nlink)
++			hin_xino(a->inode, a->h_inode); /* ignore this error */
++		mutex_unlock(&a->h_inode->i_mutex);
++	}
++
++	/* make the generation obsolete */
++	if (au_ftest_hinjob(a->flags, GEN)) {
++		int err = -1;
++		if (a->inode)
++			err = hin_gen_by_inode(a->h_name, a->h_nlen, a->inode,
++					       isdir);
++		if (err && a->dentry)
++			hin_gen_by_name(a->dentry, isdir);
++		/* ignore this error */
++	}
++
++	/* make dir entries obsolete */
++	if (au_ftest_hinjob(a->flags, DIRENT) && a->inode) {
++		struct au_vdir *vdir;
++
++		vdir = au_ivdir(a->inode);
++		if (vdir)
++			vdir->vd_jiffy = 0;
++		/* IMustLock(a->inode); */
++		/* a->inode->i_version++; */
++	}
++
++	/* can do nothing but warn */
++	if (au_ftest_hinjob(a->flags, MNTPNT)
++	    && a->dentry
++	    && d_mountpoint(a->dentry))
++		AuWarn("mount-point %.*s is removed or renamed\n",
++		       AuDLNPair(a->dentry));
++
++	return 0;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static char *in_name(u32 mask)
++{
++#ifdef CONFIG_AUFS_DEBUG
++#define test_ret(flag)	if (mask & flag) \
++				return #flag;
++	test_ret(IN_ACCESS);
++	test_ret(IN_MODIFY);
++	test_ret(IN_ATTRIB);
++	test_ret(IN_CLOSE_WRITE);
++	test_ret(IN_CLOSE_NOWRITE);
++	test_ret(IN_OPEN);
++	test_ret(IN_MOVED_FROM);
++	test_ret(IN_MOVED_TO);
++	test_ret(IN_CREATE);
++	test_ret(IN_DELETE);
++	test_ret(IN_DELETE_SELF);
++	test_ret(IN_MOVE_SELF);
++	test_ret(IN_UNMOUNT);
++	test_ret(IN_Q_OVERFLOW);
++	test_ret(IN_IGNORED);
++	return "";
++#undef test_ret
++#else
++	return "??";
++#endif
++}
++
++static struct dentry *lookup_wlock_by_name(char *name, unsigned int nlen,
++					   struct inode *dir)
++{
++	struct dentry *dentry, *d, *parent;
++	struct qstr *dname;
++
++	parent = d_find_alias(dir);
++	if (!parent)
++		return NULL;
++
++	dentry = NULL;
++	spin_lock(&dcache_lock);
++	list_for_each_entry(d, &parent->d_subdirs, d_u.d_child) {
++		/* AuDbg("%.*s\n", AuDLNPair(d)); */
++		dname = &d->d_name;
++		if (dname->len != nlen || memcmp(dname->name, name, nlen))
++			continue;
++		if (!atomic_read(&d->d_count) || !d->d_fsdata) {
++			spin_lock(&d->d_lock);
++			__d_drop(d);
++			spin_unlock(&d->d_lock);
++			continue;
++		}
++
++		dentry = dget(d);
++		break;
++	}
++	spin_unlock(&dcache_lock);
++	dput(parent);
++
++	if (dentry)
++		di_write_lock_child(dentry);
++
++	return dentry;
++}
++
++static struct inode *lookup_wlock_by_ino(struct super_block *sb,
++					 aufs_bindex_t bindex, ino_t h_ino)
++{
++	struct inode *inode;
++	ino_t ino;
++	int err;
++
++	inode = NULL;
++	err = au_xino_read(sb, bindex, h_ino, &ino);
++	if (!err && ino)
++		inode = ilookup(sb, ino);
++	if (!inode)
++		goto out;
++
++	if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
++		AuWarn("wrong root branch\n");
++		iput(inode);
++		inode = NULL;
++		goto out;
++	}
++
++	ii_write_lock_child(inode);
++
++ out:
++	return inode;
++}
++
++enum { CHILD, PARENT };
++struct postproc_args {
++	struct inode *h_dir, *dir, *h_child_inode;
++	u32 mask;
++	unsigned int flags[2];
++	unsigned int h_child_nlen;
++	char h_child_name[];
++};
++
++static void postproc(void *_args)
++{
++	struct postproc_args *a = _args;
++	struct super_block *sb;
++	aufs_bindex_t bindex, bend, bfound;
++	unsigned char xino, try_iput;
++	int err;
++	struct inode *inode;
++	ino_t h_ino;
++	struct hin_job_args args;
++	struct dentry *dentry;
++	struct au_sbinfo *sbinfo;
++
++	AuDebugOn(!_args);
++	AuDebugOn(!a->h_dir);
++	AuDebugOn(!a->dir);
++	AuDebugOn(!a->mask);
++	AuDbg("mask 0x%x %s, i%lu, hi%lu, hci%lu\n",
++	      a->mask, in_name(a->mask), a->dir->i_ino, a->h_dir->i_ino,
++	      a->h_child_inode ? a->h_child_inode->i_ino : 0);
++
++	inode = NULL;
++	dentry = NULL;
++	/*
++	 * do not lock a->dir->i_mutex here
++	 * because of d_revalidate() may cause a deadlock.
++	 */
++	sb = a->dir->i_sb;
++	AuDebugOn(!sb);
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!sbinfo);
++	/* big aufs lock */
++	si_noflush_write_lock(sb);
++
++	ii_read_lock_parent(a->dir);
++	bfound = -1;
++	bend = au_ibend(a->dir);
++	for (bindex = au_ibstart(a->dir); bindex <= bend; bindex++)
++		if (au_h_iptr(a->dir, bindex) == a->h_dir) {
++			bfound = bindex;
++			break;
++		}
++	ii_read_unlock(a->dir);
++	if (unlikely(bfound < 0))
++		goto out;
++
++	xino = !!au_opt_test(au_mntflags(sb), XINO);
++	h_ino = 0;
++	if (a->h_child_inode)
++		h_ino = a->h_child_inode->i_ino;
++
++	if (a->h_child_nlen
++	    && (au_ftest_hinjob(a->flags[CHILD], GEN)
++		|| au_ftest_hinjob(a->flags[CHILD], MNTPNT)))
++		dentry = lookup_wlock_by_name(a->h_child_name, a->h_child_nlen,
++					      a->dir);
++	try_iput = 0;
++	if (dentry)
++		inode = dentry->d_inode;
++	if (xino && !inode && h_ino
++	    && (au_ftest_hinjob(a->flags[CHILD], XINO0)
++		|| au_ftest_hinjob(a->flags[CHILD], TRYXINO0)
++		|| au_ftest_hinjob(a->flags[CHILD], GEN))) {
++		inode = lookup_wlock_by_ino(sb, bfound, h_ino);
++		try_iput = 1;
++	    }
++
++	args.flags = a->flags[CHILD];
++	args.dentry = dentry;
++	args.inode = inode;
++	args.h_inode = a->h_child_inode;
++	args.dir = a->dir;
++	args.h_dir = a->h_dir;
++	args.h_name = a->h_child_name;
++	args.h_nlen = a->h_child_nlen;
++	err = hin_job(&args);
++	if (dentry) {
++		if (dentry->d_fsdata)
++			di_write_unlock(dentry);
++		dput(dentry);
++	}
++	if (inode && try_iput) {
++		ii_write_unlock(inode);
++		iput(inode);
++	}
++
++	ii_write_lock_parent(a->dir);
++	args.flags = a->flags[PARENT];
++	args.dentry = NULL;
++	args.inode = a->dir;
++	args.h_inode = a->h_dir;
++	args.dir = NULL;
++	args.h_dir = NULL;
++	args.h_name = NULL;
++	args.h_nlen = 0;
++	err = hin_job(&args);
++	ii_write_unlock(a->dir);
++
++ out:
++	au_nwt_done(&sbinfo->si_nowait);
++	si_write_unlock(sb);
++
++	iput(a->h_child_inode);
++	iput(a->h_dir);
++	iput(a->dir);
++	kfree(a);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void aufs_inotify(struct inotify_watch *watch, u32 wd __maybe_unused,
++			 u32 mask, u32 cookie __maybe_unused,
++			 const char *h_child_name, struct inode *h_child_inode)
++{
++	struct au_hinotify *hinotify;
++	struct postproc_args *args;
++	int len, wkq_err;
++	unsigned char isdir, isroot, wh;
++	char *p;
++	struct inode *dir;
++	unsigned int flags[2];
++
++	/* if IN_UNMOUNT happens, there must be another bug */
++	AuDebugOn(mask & IN_UNMOUNT);
++	if (mask & (IN_IGNORED | IN_UNMOUNT)) {
++		put_inotify_watch(watch);
++		return;
++	}
++#ifdef AuDbgHinotify
++	au_debug(1);
++	if (1 || !h_child_name || strcmp(h_child_name, AUFS_XINO_FNAME)) {
++		AuDbg("i%lu, wd %d, mask 0x%x %s, cookie 0x%x, hcname %s,"
++		      " hi%lu\n",
++		      watch->inode->i_ino, wd, mask, in_name(mask), cookie,
++		      h_child_name ? h_child_name : "",
++		      h_child_inode ? h_child_inode->i_ino : 0);
++		WARN_ON(1);
++	}
++	au_debug(0);
++#endif
++
++	hinotify = container_of(watch, struct au_hinotify, hin_watch);
++	AuDebugOn(!hinotify || !hinotify->hin_aufs_inode);
++	dir = igrab(hinotify->hin_aufs_inode);
++	if (!dir)
++		return;
++
++	isroot = (dir->i_ino == AUFS_ROOT_INO);
++	len = 0;
++	wh = 0;
++	if (h_child_name) {
++		len = strlen(h_child_name);
++		if (!memcmp(h_child_name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
++			h_child_name += AUFS_WH_PFX_LEN;
++			len -= AUFS_WH_PFX_LEN;
++			wh = 1;
++		}
++	}
++
++	isdir = 0;
++	if (h_child_inode)
++		isdir = !!S_ISDIR(h_child_inode->i_mode);
++	flags[PARENT] = AuHinJob_ISDIR;
++	flags[CHILD] = 0;
++	if (isdir)
++		flags[CHILD] = AuHinJob_ISDIR;
++	switch (mask & IN_ALL_EVENTS) {
++	case IN_MOVED_FROM:
++	case IN_MOVED_TO:
++		AuDebugOn(!h_child_name || !h_child_inode);
++		au_fset_hinjob(flags[CHILD], GEN);
++		au_fset_hinjob(flags[CHILD], XINO0);
++		au_fset_hinjob(flags[CHILD], MNTPNT);
++		au_fset_hinjob(flags[PARENT], DIRENT);
++		break;
++
++	case IN_CREATE:
++		AuDebugOn(!h_child_name || !h_child_inode);
++		au_fset_hinjob(flags[PARENT], DIRENT);
++		au_fset_hinjob(flags[CHILD], GEN);
++		break;
++
++	case IN_DELETE:
++		/*
++		 * aufs never be able to get this child inode.
++		 * revalidation should be in d_revalidate()
++		 * by checking i_nlink, i_generation or d_unhashed().
++		 */
++		AuDebugOn(!h_child_name);
++		au_fset_hinjob(flags[PARENT], DIRENT);
++		au_fset_hinjob(flags[CHILD], GEN);
++		au_fset_hinjob(flags[CHILD], TRYXINO0);
++		au_fset_hinjob(flags[CHILD], MNTPNT);
++		break;
++
++	default:
++		AuDebugOn(1);
++	}
++
++	if (wh)
++		h_child_inode = NULL;
++
++	/* iput() and kfree() will be called in postproc() */
++	/*
++	 * inotify_mutex is already acquired and kmalloc/prune_icache may lock
++	 * iprune_mutex. strange.
++	 */
++	lockdep_off();
++	args = kmalloc(sizeof(*args) + len + 1, GFP_NOFS);
++	lockdep_on();
++	if (unlikely(!args)) {
++		AuErr1("no memory\n");
++		iput(dir);
++		return;
++	}
++	args->flags[PARENT] = flags[PARENT];
++	args->flags[CHILD] = flags[CHILD];
++	args->mask = mask;
++	args->dir = dir;
++	args->h_dir = igrab(watch->inode);
++	if (h_child_inode)
++		h_child_inode = igrab(h_child_inode); /* can be NULL */
++	args->h_child_inode = h_child_inode;
++	args->h_child_nlen = len;
++	if (len) {
++		p = (void *)args;
++		p += sizeof(*args);
++		memcpy(p, h_child_name, len + 1);
++	}
++
++	lockdep_off();
++	wkq_err = au_wkq_nowait(postproc, args, dir->i_sb);
++	lockdep_on();
++	if (unlikely(wkq_err))
++		AuErr("wkq %d\n", wkq_err);
++}
++
++static void aufs_inotify_destroy(struct inotify_watch *watch __maybe_unused)
++{
++	return;
++}
++
++static struct inotify_operations aufs_inotify_ops = {
++	.handle_event	= aufs_inotify,
++	.destroy_watch	= aufs_inotify_destroy
++};
++
++/* ---------------------------------------------------------------------- */
++
++static void au_hin_destroy_cache(void)
++{
++	kmem_cache_destroy(au_cachep[AuCache_HINOTIFY]);
++	au_cachep[AuCache_HINOTIFY] = NULL;
++}
++
++int __init au_hinotify_init(void)
++{
++	int err;
++
++	err = -ENOMEM;
++	au_cachep[AuCache_HINOTIFY] = AuCache(au_hinotify);
++	if (au_cachep[AuCache_HINOTIFY]) {
++		err = 0;
++		au_hin_handle = inotify_init(&aufs_inotify_ops);
++		if (IS_ERR(au_hin_handle)) {
++			err = PTR_ERR(au_hin_handle);
++			au_hin_destroy_cache();
++		}
++	}
++	AuTraceErr(err);
++	return err;
++}
++
++void au_hinotify_fin(void)
++{
++	inotify_destroy(au_hin_handle);
++	if (au_cachep[AuCache_HINOTIFY])
++		au_hin_destroy_cache();
++}
+diff -uNr test/fs/aufs/i_op.c aufs2-standalone/fs/aufs/i_op.c
+--- test/fs/aufs/i_op.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/i_op.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,858 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * inode operations (except add/del/rename)
++ */
++
++#include <linux/device_cgroup.h>
++#include <linux/fs_stack.h>
++#include <linux/uaccess.h>
++#include "aufs.h"
++
++static int h_permission(struct inode *h_inode, int mask,
++			struct vfsmount *h_mnt, int brperm)
++{
++	int err;
++	const unsigned char write_mask = !!(mask & (MAY_WRITE | MAY_APPEND));
++
++	err = -EACCES;
++	if ((write_mask && IS_IMMUTABLE(h_inode))
++	    || ((mask & MAY_EXEC)
++		&& S_ISREG(h_inode->i_mode)
++		&& ((h_mnt->mnt_flags & MNT_NOEXEC)
++		    || !(h_inode->i_mode & S_IXUGO))))
++		goto out;
++
++	/*
++	 * - skip the lower fs test in the case of write to ro branch.
++	 * - nfs dir permission write check is optimized, but a policy for
++	 *   link/rename requires a real check.
++	 */
++	if ((write_mask && !au_br_writable(brperm))
++	    || (au_test_nfs(h_inode->i_sb) && S_ISDIR(h_inode->i_mode)
++		&& write_mask && !(mask & MAY_READ))
++	    || !h_inode->i_op
++	    || !h_inode->i_op->permission) {
++		/* AuLabel(generic_permission); */
++		err = generic_permission(h_inode, mask, NULL);
++	} else {
++		/* AuLabel(h_inode->permission); */
++		err = h_inode->i_op->permission(h_inode, mask);
++		AuTraceErr(err);
++	}
++
++	if (!err)
++		err = devcgroup_inode_permission(h_inode, mask);
++	if (!err)
++		err = security_inode_permission
++			(h_inode, mask & (MAY_READ | MAY_WRITE | MAY_EXEC
++					  | MAY_APPEND));
++
++ out:
++	return err;
++}
++
++static int aufs_permission(struct inode *inode, int mask)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	const unsigned char isdir = !!S_ISDIR(inode->i_mode);
++	const unsigned char write_mask = !!(mask & (MAY_WRITE | MAY_APPEND));
++	struct inode *h_inode;
++	struct super_block *sb;
++	struct au_branch *br;
++
++	sb = inode->i_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	ii_read_lock_child(inode);
++
++	if (!isdir || write_mask) {
++		h_inode = au_h_iptr(inode, au_ibstart(inode));
++		AuDebugOn(!h_inode
++			  || ((h_inode->i_mode & S_IFMT)
++			      != (inode->i_mode & S_IFMT)));
++		err = 0;
++		bindex = au_ibstart(inode);
++		br = au_sbr(sb, bindex);
++		err = h_permission(h_inode, mask, br->br_mnt, br->br_perm);
++
++		if (write_mask && !err) {
++			/* test whether the upper writable branch exists */
++			err = -EROFS;
++			for (; bindex >= 0; bindex--)
++				if (!au_br_rdonly(au_sbr(sb, bindex))) {
++					err = 0;
++					break;
++				}
++		}
++		goto out;
++	}
++
++	/* non-write to dir */
++	err = 0;
++	bend = au_ibend(inode);
++	for (bindex = au_ibstart(inode); !err && bindex <= bend; bindex++) {
++		h_inode = au_h_iptr(inode, bindex);
++		if (h_inode) {
++			AuDebugOn(!S_ISDIR(h_inode->i_mode));
++			br = au_sbr(sb, bindex);
++			err = h_permission(h_inode, mask, br->br_mnt,
++					   br->br_perm);
++		}
++	}
++
++ out:
++	ii_read_unlock(inode);
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static struct dentry *aufs_lookup(struct inode *dir, struct dentry *dentry,
++				  struct nameidata *nd)
++{
++	struct dentry *ret, *parent;
++	struct inode *inode, *h_inode;
++	struct mutex *mtx;
++	struct super_block *sb;
++	int err, npositive;
++	aufs_bindex_t bstart;
++
++	IMustLock(dir);
++
++	sb = dir->i_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	err = au_alloc_dinfo(dentry);
++	ret = ERR_PTR(err);
++	if (unlikely(err))
++		goto out;
++
++	parent = dentry->d_parent; /* dir inode is locked */
++	di_read_lock_parent(parent, AuLock_IR);
++	npositive = au_lkup_dentry(dentry, au_dbstart(parent), /*type*/0, nd);
++	di_read_unlock(parent, AuLock_IR);
++	err = npositive;
++	ret = ERR_PTR(err);
++	if (unlikely(err < 0))
++		goto out_unlock;
++
++	inode = NULL;
++	if (npositive) {
++		bstart = au_dbstart(dentry);
++		h_inode = au_h_dptr(dentry, bstart)->d_inode;
++		if (!S_ISDIR(h_inode->i_mode)) {
++			/*
++			 * stop 'race'-ing between hardlinks under different
++			 * parents.
++			 */
++			mtx = &au_sbr(sb, bstart)->br_xino.xi_nondir_mtx;
++			mutex_lock(mtx);
++			inode = au_new_inode(dentry, /*must_new*/0);
++			mutex_unlock(mtx);
++		} else
++			inode = au_new_inode(dentry, /*must_new*/0);
++		ret = (void *)inode;
++	}
++	if (IS_ERR(inode))
++		goto out_unlock;
++
++	ret = d_splice_alias(inode, dentry);
++	if (unlikely(IS_ERR(ret) && inode))
++		ii_write_unlock(inode);
++	au_store_oflag(nd);
++
++ out_unlock:
++	di_write_unlock(dentry);
++ out:
++	si_read_unlock(sb);
++	return ret;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_wr_dir_cpup(struct dentry *dentry, struct dentry *parent,
++			  const unsigned char add_entry, aufs_bindex_t bcpup,
++			  aufs_bindex_t bstart)
++{
++	int err;
++	struct dentry *h_parent;
++	struct inode *h_dir;
++
++	if (add_entry) {
++		au_update_dbstart(dentry);
++		IMustLock(parent->d_inode);
++	} else
++		di_write_lock_parent(parent);
++
++	err = 0;
++	if (!au_h_dptr(parent, bcpup)) {
++		if (bstart < bcpup)
++			err = au_cpdown_dirs(dentry, bcpup);
++		else
++			err = au_cpup_dirs(dentry, bcpup);
++	}
++	if (!err && add_entry) {
++		h_parent = au_h_dptr(parent, bcpup);
++		h_dir = h_parent->d_inode;
++		mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
++		err = au_lkup_neg(dentry, bcpup);
++		/* todo: no unlock here */
++		mutex_unlock(&h_dir->i_mutex);
++		if (bstart < bcpup && au_dbstart(dentry) < 0) {
++			au_set_dbstart(dentry, 0);
++			au_update_dbrange(dentry, /*do_put_zero*/0);
++		}
++	}
++
++	if (!add_entry)
++		di_write_unlock(parent);
++	if (!err)
++		err = bcpup; /* success */
++
++	return err;
++}
++
++/*
++ * decide the branch and the parent dir where we will create a new entry.
++ * returns new bindex or an error.
++ * copyup the parent dir if needed.
++ */
++int au_wr_dir(struct dentry *dentry, struct dentry *src_dentry,
++	      struct au_wr_dir_args *args)
++{
++	int err;
++	aufs_bindex_t bcpup, bstart, src_bstart;
++	const unsigned char add_entry = !!au_ftest_wrdir(args->flags,
++							 ADD_ENTRY);
++	struct super_block *sb;
++	struct dentry *parent;
++	struct au_sbinfo *sbinfo;
++
++	sb = dentry->d_sb;
++	sbinfo = au_sbi(sb);
++	parent = dget_parent(dentry);
++	bstart = au_dbstart(dentry);
++	bcpup = bstart;
++	if (args->force_btgt < 0) {
++		if (src_dentry) {
++			src_bstart = au_dbstart(src_dentry);
++			if (src_bstart < bstart)
++				bcpup = src_bstart;
++		} else if (add_entry) {
++			err = AuWbrCreate(sbinfo, dentry,
++					  au_ftest_wrdir(args->flags, ISDIR));
++			bcpup = err;
++		}
++
++		if (bcpup < 0 || au_test_ro(sb, bcpup, dentry->d_inode)) {
++			if (add_entry)
++				err = AuWbrCopyup(sbinfo, dentry);
++			else {
++				if (!IS_ROOT(dentry)) {
++					di_read_lock_parent(parent, !AuLock_IR);
++					err = AuWbrCopyup(sbinfo, dentry);
++					di_read_unlock(parent, !AuLock_IR);
++				} else
++					err = AuWbrCopyup(sbinfo, dentry);
++			}
++			bcpup = err;
++			if (unlikely(err < 0))
++				goto out;
++		}
++	} else {
++		bcpup = args->force_btgt;
++		AuDebugOn(au_test_ro(sb, bcpup, dentry->d_inode));
++	}
++	AuDbg("bstart %d, bcpup %d\n", bstart, bcpup);
++	if (bstart < bcpup)
++		au_update_dbrange(dentry, /*do_put_zero*/1);
++
++	err = bcpup;
++	if (bcpup == bstart)
++		goto out; /* success */
++
++	/* copyup the new parent into the branch we process */
++	err = au_wr_dir_cpup(dentry, parent, add_entry, bcpup, bstart);
++
++ out:
++	dput(parent);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct dentry *au_pinned_h_parent(struct au_pin *pin)
++{
++	if (pin && pin->parent)
++		return au_h_dptr(pin->parent, pin->bindex);
++	return NULL;
++}
++
++void au_unpin(struct au_pin *p)
++{
++	if (au_ftest_pin(p->flags, MNT_WRITE))
++		mnt_drop_write(p->h_mnt);
++	if (!p->hdir)
++		return;
++
++	au_hin_imtx_unlock(p->hdir);
++	if (!au_ftest_pin(p->flags, DI_LOCKED))
++		di_read_unlock(p->parent, AuLock_IR);
++	iput(p->hdir->hi_inode);
++	dput(p->parent);
++	p->parent = NULL;
++	p->hdir = NULL;
++	p->h_mnt = NULL;
++}
++
++int au_do_pin(struct au_pin *p)
++{
++	int err;
++	struct super_block *sb;
++	struct dentry *h_dentry, *h_parent;
++	struct au_branch *br;
++	struct inode *h_dir;
++
++	err = 0;
++	sb = p->dentry->d_sb;
++	br = au_sbr(sb, p->bindex);
++	if (IS_ROOT(p->dentry)) {
++		if (au_ftest_pin(p->flags, MNT_WRITE)) {
++			p->h_mnt = br->br_mnt;
++			err = mnt_want_write(p->h_mnt);
++			if (unlikely(err)) {
++				au_fclr_pin(p->flags, MNT_WRITE);
++				goto out_err;
++			}
++		}
++		goto out;
++	}
++
++	h_dentry = NULL;
++	if (p->bindex <= au_dbend(p->dentry))
++		h_dentry = au_h_dptr(p->dentry, p->bindex);
++
++	p->parent = dget_parent(p->dentry);
++	if (!au_ftest_pin(p->flags, DI_LOCKED))
++		di_read_lock(p->parent, AuLock_IR, p->lsc_di);
++
++	h_dir = NULL;
++	h_parent = au_h_dptr(p->parent, p->bindex);
++	p->hdir = au_hi(p->parent->d_inode, p->bindex);
++	if (p->hdir)
++		h_dir = p->hdir->hi_inode;
++
++	/* udba case */
++	if (unlikely(!p->hdir || !h_dir)) {
++		err = -EBUSY;
++		if (!au_ftest_pin(p->flags, DI_LOCKED))
++			di_read_unlock(p->parent, AuLock_IR);
++		dput(p->parent);
++		p->parent = NULL;
++		goto out_err;
++	}
++
++	au_igrab(h_dir);
++	au_hin_imtx_lock_nested(p->hdir, p->lsc_hi);
++
++	if (h_dentry) {
++		err = au_h_verify(h_dentry, p->udba, h_dir, h_parent, br);
++		if (unlikely(err)) {
++			au_fclr_pin(p->flags, MNT_WRITE);
++			goto out_unpin;
++		}
++	}
++
++	if (au_ftest_pin(p->flags, MNT_WRITE)) {
++		p->h_mnt = br->br_mnt;
++		err = mnt_want_write(p->h_mnt);
++		if (unlikely(err)) {
++			au_fclr_pin(p->flags, MNT_WRITE);
++			goto out_unpin;
++		}
++	}
++	goto out; /* success */
++
++ out_unpin:
++	au_unpin(p);
++ out_err:
++	AuErr("err %d\n", err);
++	err = -EBUSY;
++ out:
++	return err;
++}
++
++void au_pin_init(struct au_pin *p, struct dentry *dentry,
++		 aufs_bindex_t bindex, int lsc_di, int lsc_hi,
++		 unsigned int udba, unsigned char flags)
++{
++	p->dentry = dentry;
++	p->udba = udba;
++	p->lsc_di = lsc_di;
++	p->lsc_hi = lsc_hi;
++	p->flags = flags;
++	p->bindex = bindex;
++
++	p->parent = NULL;
++	p->hdir = NULL;
++	p->h_mnt = NULL;
++}
++
++int au_pin(struct au_pin *pin, struct dentry *dentry, aufs_bindex_t bindex,
++	   unsigned int udba, unsigned char flags)
++{
++	au_pin_init(pin, dentry, bindex, AuLsc_DI_PARENT, AuLsc_I_PARENT2,
++		    udba, flags);
++	return au_do_pin(pin);
++}
++
++/* ---------------------------------------------------------------------- */
++
++#define AuIcpup_DID_CPUP	1
++#define au_ftest_icpup(flags, name)	((flags) & AuIcpup_##name)
++#define au_fset_icpup(flags, name)	{ (flags) |= AuIcpup_##name; }
++#define au_fclr_icpup(flags, name)	{ (flags) &= ~AuIcpup_##name; }
++
++struct au_icpup_args {
++	unsigned char flags;
++	unsigned char pin_flags;
++	aufs_bindex_t btgt;
++	struct au_pin pin;
++	struct path h_path;
++	struct inode *h_inode;
++};
++
++static int au_lock_and_icpup(struct dentry *dentry, struct iattr *ia,
++			     struct au_icpup_args *a)
++{
++	int err;
++	unsigned int udba;
++	loff_t sz;
++	aufs_bindex_t bstart;
++	struct dentry *hi_wh, *parent;
++	struct inode *inode;
++	struct au_wr_dir_args wr_dir_args = {
++		.force_btgt	= -1,
++		.flags		= 0
++	};
++
++	di_write_lock_child(dentry);
++	bstart = au_dbstart(dentry);
++	inode = dentry->d_inode;
++	if (S_ISDIR(inode->i_mode))
++		au_fset_wrdir(wr_dir_args.flags, ISDIR);
++	/* plink or hi_wh() case */
++	if (bstart != au_ibstart(inode))
++		wr_dir_args.force_btgt = au_ibstart(inode);
++	err = au_wr_dir(dentry, /*src_dentry*/NULL, &wr_dir_args);
++	if (unlikely(err < 0))
++		goto out_dentry;
++	a->btgt = err;
++	if (err != bstart)
++		au_fset_icpup(a->flags, DID_CPUP);
++
++	err = 0;
++	a->pin_flags = AuPin_MNT_WRITE;
++	parent = NULL;
++	if (!IS_ROOT(dentry)) {
++		au_fset_pin(a->pin_flags, DI_LOCKED);
++		parent = dget_parent(dentry);
++		di_write_lock_parent(parent);
++	}
++
++	udba = au_opt_udba(dentry->d_sb);
++	if (d_unhashed(dentry) || (ia->ia_valid & ATTR_FILE))
++		udba = AuOpt_UDBA_NONE;
++	err = au_pin(&a->pin, dentry, a->btgt, udba, a->pin_flags);
++	if (unlikely(err)) {
++		if (parent) {
++			di_write_unlock(parent);
++			dput(parent);
++		}
++		goto out_dentry;
++	}
++	a->h_path.dentry = au_h_dptr(dentry, bstart);
++	a->h_inode = a->h_path.dentry->d_inode;
++	mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
++	sz = -1;
++	if ((ia->ia_valid & ATTR_SIZE) && ia->ia_size < i_size_read(a->h_inode))
++		sz = ia->ia_size;
++
++	hi_wh = NULL;
++	if (au_ftest_icpup(a->flags, DID_CPUP) && d_unhashed(dentry)) {
++		hi_wh = au_hi_wh(inode, a->btgt);
++		if (!hi_wh) {
++			err = au_sio_cpup_wh(dentry, a->btgt, sz, /*file*/NULL);
++			if (unlikely(err))
++				goto out_unlock;
++			hi_wh = au_hi_wh(inode, a->btgt);
++			/* todo: revalidate hi_wh? */
++		}
++	}
++
++	if (parent) {
++		au_pin_set_parent_lflag(&a->pin, /*lflag*/0);
++		di_downgrade_lock(parent, AuLock_IR);
++		dput(parent);
++	}
++	if (!au_ftest_icpup(a->flags, DID_CPUP))
++		goto out; /* success */
++
++	if (!d_unhashed(dentry)) {
++		err = au_sio_cpup_simple(dentry, a->btgt, sz, AuCpup_DTIME);
++		if (!err)
++			a->h_path.dentry = au_h_dptr(dentry, a->btgt);
++	} else if (!hi_wh)
++		a->h_path.dentry = au_h_dptr(dentry, a->btgt);
++	else
++		a->h_path.dentry = hi_wh; /* do not dget here */
++
++ out_unlock:
++	mutex_unlock(&a->h_inode->i_mutex);
++	a->h_inode = a->h_path.dentry->d_inode;
++	if (!err) {
++		mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
++		goto out; /* success */
++	}
++
++	au_unpin(&a->pin);
++
++ out_dentry:
++	di_write_unlock(dentry);
++ out:
++	return err;
++}
++
++static int aufs_setattr(struct dentry *dentry, struct iattr *ia)
++{
++	int err;
++	struct inode *inode;
++	struct super_block *sb;
++	struct file *file;
++	struct au_icpup_args *a;
++
++	err = -ENOMEM;
++	a = kzalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	inode = dentry->d_inode;
++	IMustLock(inode);
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++
++	file = NULL;
++	if (ia->ia_valid & ATTR_FILE) {
++		/* currently ftruncate(2) only */
++		file = ia->ia_file;
++		fi_write_lock(file);
++		ia->ia_file = au_h_fptr(file, au_fbstart(file));
++	}
++
++	if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
++		ia->ia_valid &= ~ATTR_MODE;
++
++	err = au_lock_and_icpup(dentry, ia, a);
++	if (unlikely(err < 0))
++		goto out_si;
++	if (au_ftest_icpup(a->flags, DID_CPUP)) {
++		ia->ia_file = NULL;
++		ia->ia_valid &= ~ATTR_FILE;
++	}
++
++	a->h_path.mnt = au_sbr_mnt(sb, a->btgt);
++	if (ia->ia_valid & ATTR_SIZE) {
++		struct file *f;
++
++		if (ia->ia_size < i_size_read(inode)) {
++			/* unmap only */
++			err = vmtruncate(inode, ia->ia_size);
++			if (unlikely(err))
++				goto out_unlock;
++		}
++
++		f = NULL;
++		if (ia->ia_valid & ATTR_FILE)
++			f = ia->ia_file;
++		mutex_unlock(&a->h_inode->i_mutex);
++		err = vfsub_trunc(&a->h_path, ia->ia_size, ia->ia_valid, f);
++		mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
++	} else
++		err = vfsub_notify_change(&a->h_path, ia);
++	if (!err)
++		au_cpup_attr_changeable(inode);
++
++ out_unlock:
++	mutex_unlock(&a->h_inode->i_mutex);
++	au_unpin(&a->pin);
++	di_write_unlock(dentry);
++ out_si:
++	if (file) {
++		fi_write_unlock(file);
++		ia->ia_file = file;
++		ia->ia_valid |= ATTR_FILE;
++	}
++	si_read_unlock(sb);
++	kfree(a);
++ out:
++	return err;
++}
++
++static int au_getattr_lock_reval(struct dentry *dentry, unsigned int sigen)
++{
++	int err;
++	struct inode *inode;
++	struct dentry *parent;
++
++	err = 0;
++	inode = dentry->d_inode;
++	di_write_lock_child(dentry);
++	if (au_digen(dentry) != sigen || au_iigen(inode) != sigen) {
++		parent = dget_parent(dentry);
++		di_read_lock_parent(parent, AuLock_IR);
++		/* returns a number of positive dentries */
++		err = au_refresh_hdentry(dentry, inode->i_mode & S_IFMT);
++		if (err > 0)
++			err = au_refresh_hinode(inode, dentry);
++		di_read_unlock(parent, AuLock_IR);
++		dput(parent);
++		if (unlikely(!err))
++			err = -EIO;
++	}
++	di_downgrade_lock(dentry, AuLock_IR);
++
++	return err;
++}
++
++static void au_refresh_iattr(struct inode *inode, struct kstat *st,
++			     unsigned int nlink)
++{
++	inode->i_mode = st->mode;
++	inode->i_uid = st->uid;
++	inode->i_gid = st->gid;
++	inode->i_atime = st->atime;
++	inode->i_mtime = st->mtime;
++	inode->i_ctime = st->ctime;
++
++	au_cpup_attr_nlink(inode, /*force*/0);
++	if (S_ISDIR(inode->i_mode)) {
++		inode->i_nlink -= nlink;
++		inode->i_nlink += st->nlink;
++	}
++
++	spin_lock(&inode->i_lock);
++	inode->i_blocks = st->blocks;
++	i_size_write(inode, st->size);
++	spin_unlock(&inode->i_lock);
++}
++
++static int aufs_getattr(struct vfsmount *mnt __maybe_unused,
++			struct dentry *dentry, struct kstat *st)
++{
++	int err;
++	unsigned int mnt_flags;
++	aufs_bindex_t bindex;
++	unsigned char udba_none, positive, did_lock;
++	struct super_block *sb, *h_sb;
++	struct inode *inode;
++	struct vfsmount *h_mnt;
++	struct dentry *h_dentry;
++
++	err = 0;
++	did_lock = 0;
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	si_read_lock(sb, AuLock_FLUSH);
++	if (IS_ROOT(dentry)) {
++		/* lock free root dinfo */
++		h_dentry = dget(au_di(dentry)->di_hdentry->hd_dentry);
++		h_mnt = au_sbr_mnt(sb, 0);
++		goto getattr;
++	}
++
++	did_lock = 1;
++	mnt_flags = au_mntflags(sb);
++	udba_none = !!au_opt_test(mnt_flags, UDBA_NONE);
++
++	/* support fstat(2) */
++	if (!d_unhashed(dentry) && !udba_none) {
++		unsigned int sigen = au_sigen(sb);
++		if (au_digen(dentry) == sigen && au_iigen(inode) == sigen)
++			di_read_lock_child(dentry, AuLock_IR);
++		else {
++			err = au_getattr_lock_reval(dentry, sigen);
++			if (unlikely(err))
++				goto out;
++		}
++	} else
++		di_read_lock_child(dentry, AuLock_IR);
++
++	bindex = au_ibstart(inode);
++	h_mnt = au_sbr_mnt(sb, bindex);
++	h_sb = h_mnt->mnt_sb;
++	if (!au_test_fs_bad_iattr(h_sb) && udba_none)
++		goto out_fill; /* success */
++
++	if (au_dbstart(dentry) == bindex)
++		h_dentry = dget(au_h_dptr(dentry, bindex));
++	else if (au_opt_test(mnt_flags, PLINK) && au_plink_test(inode)) {
++		h_dentry = au_plink_lkup(inode, bindex);
++		if (IS_ERR(h_dentry))
++			goto out_fill; /* pretending success */
++	} else
++		/* illegally overlapped or something */
++		goto out_fill; /* pretending success */
++
++ getattr:
++	positive = !!h_dentry->d_inode;
++	if (positive)
++		err = vfs_getattr(h_mnt, h_dentry, st);
++	dput(h_dentry);
++	if (!err) {
++		if (positive)
++			au_refresh_iattr(inode, st, h_dentry->d_inode->i_nlink);
++		goto out_fill; /* success */
++	}
++	goto out;
++
++ out_fill:
++	generic_fillattr(inode, st);
++ out:
++	if (did_lock)
++		di_read_unlock(dentry, AuLock_IR);
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int h_readlink(struct dentry *dentry, int bindex, char __user *buf,
++		      int bufsiz)
++{
++	int err;
++	struct super_block *sb;
++	struct dentry *h_dentry;
++
++	err = -EINVAL;
++	h_dentry = au_h_dptr(dentry, bindex);
++	if (unlikely(/* !h_dentry
++		     || !h_dentry->d_inode
++		     || */ !h_dentry->d_inode->i_op
++		     || !h_dentry->d_inode->i_op->readlink))
++		goto out;
++
++	err = security_inode_readlink(h_dentry);
++	if (unlikely(err))
++		goto out;
++
++	sb = dentry->d_sb;
++	if (!au_test_ro(sb, bindex, dentry->d_inode)) {
++		vfsub_touch_atime(au_sbr_mnt(sb, bindex), h_dentry);
++		fsstack_copy_attr_atime(dentry->d_inode, h_dentry->d_inode);
++	}
++	err = h_dentry->d_inode->i_op->readlink(h_dentry, buf, bufsiz);
++
++ out:
++	return err;
++}
++
++static int aufs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
++{
++	int err;
++
++	aufs_read_lock(dentry, AuLock_IR);
++	err = h_readlink(dentry, au_dbstart(dentry), buf, bufsiz);
++	aufs_read_unlock(dentry, AuLock_IR);
++
++	return err;
++}
++
++static void *aufs_follow_link(struct dentry *dentry, struct nameidata *nd)
++{
++	int err;
++	char *buf;
++	mm_segment_t old_fs;
++
++	err = -ENOMEM;
++	buf = __getname();
++	if (unlikely(!buf))
++		goto out;
++
++	aufs_read_lock(dentry, AuLock_IR);
++	old_fs = get_fs();
++	set_fs(KERNEL_DS);
++	err = h_readlink(dentry, au_dbstart(dentry), (char __user *)buf,
++			 PATH_MAX);
++	set_fs(old_fs);
++	aufs_read_unlock(dentry, AuLock_IR);
++
++	if (err >= 0) {
++		buf[err] = 0;
++		/* will be freed by put_link */
++		nd_set_link(nd, buf);
++		return NULL; /* success */
++	}
++	__putname(buf);
++
++ out:
++	path_put(&nd->path);
++	AuTraceErr(err);
++	return ERR_PTR(err);
++}
++
++static void aufs_put_link(struct dentry *dentry __maybe_unused,
++			  struct nameidata *nd, void *cookie __maybe_unused)
++{
++	__putname(nd_get_link(nd));
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void aufs_truncate_range(struct inode *inode __maybe_unused,
++				loff_t start __maybe_unused,
++				loff_t end __maybe_unused)
++{
++	AuUnsupport();
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct inode_operations aufs_symlink_iop = {
++	.permission	= aufs_permission,
++	.setattr	= aufs_setattr,
++	.getattr	= aufs_getattr,
++	.readlink	= aufs_readlink,
++	.follow_link	= aufs_follow_link,
++	.put_link	= aufs_put_link
++};
++
++struct inode_operations aufs_dir_iop = {
++	.create		= aufs_create,
++	.lookup		= aufs_lookup,
++	.link		= aufs_link,
++	.unlink		= aufs_unlink,
++	.symlink	= aufs_symlink,
++	.mkdir		= aufs_mkdir,
++	.rmdir		= aufs_rmdir,
++	.mknod		= aufs_mknod,
++	.rename		= aufs_rename,
++
++	.permission	= aufs_permission,
++	.setattr	= aufs_setattr,
++	.getattr	= aufs_getattr
++};
++
++struct inode_operations aufs_iop = {
++	.permission	= aufs_permission,
++	.setattr	= aufs_setattr,
++	.getattr	= aufs_getattr,
++	.truncate_range	= aufs_truncate_range
++};
+diff -uNr test/fs/aufs/i_op_add.c aufs2-standalone/fs/aufs/i_op_add.c
+--- test/fs/aufs/i_op_add.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/i_op_add.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,625 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * inode operations (add entry)
++ */
++
++#include "aufs.h"
++
++/*
++ * final procedure of adding a new entry, except link(2).
++ * remove whiteout, instantiate, copyup the parent dir's times and size
++ * and update version.
++ * if it failed, re-create the removed whiteout.
++ */
++static int epilog(struct inode *dir, aufs_bindex_t bindex,
++		  struct dentry *wh_dentry, struct dentry *dentry)
++{
++	int err, rerr;
++	aufs_bindex_t bwh;
++	struct path h_path;
++	struct inode *inode, *h_dir;
++	struct dentry *wh;
++
++	bwh = -1;
++	if (wh_dentry) {
++		h_dir = wh_dentry->d_parent->d_inode; /* dir inode is locked */
++		IMustLock(h_dir);
++		AuDebugOn(au_h_iptr(dir, bindex) != h_dir);
++		bwh = au_dbwh(dentry);
++		h_path.dentry = wh_dentry;
++		h_path.mnt = au_sbr_mnt(dir->i_sb, bindex);
++		err = au_wh_unlink_dentry(au_h_iptr(dir, bindex), &h_path,
++					  dentry);
++		if (unlikely(err))
++			goto out;
++	}
++
++	inode = au_new_inode(dentry, /*must_new*/1);
++	if (!IS_ERR(inode)) {
++		d_instantiate(dentry, inode);
++		dir = dentry->d_parent->d_inode; /* dir inode is locked */
++		IMustLock(dir);
++		if (au_ibstart(dir) == au_dbstart(dentry))
++			au_cpup_attr_timesizes(dir);
++		dir->i_version++;
++		return 0; /* success */
++	}
++
++	err = PTR_ERR(inode);
++	if (!wh_dentry)
++		goto out;
++
++	/* revert */
++	/* dir inode is locked */
++	wh = au_wh_create(dentry, bwh, wh_dentry->d_parent);
++	rerr = PTR_ERR(wh);
++	if (IS_ERR(wh)) {
++		AuIOErr("%.*s reverting whiteout failed(%d, %d)\n",
++			AuDLNPair(dentry), err, rerr);
++		err = -EIO;
++	} else
++		dput(wh);
++
++ out:
++	return err;
++}
++
++/*
++ * simple tests for the adding inode operations.
++ * following the checks in vfs, plus the parent-child relationship.
++ */
++int au_may_add(struct dentry *dentry, aufs_bindex_t bindex,
++	       struct dentry *h_parent, int isdir)
++{
++	int err;
++	umode_t h_mode;
++	struct dentry *h_dentry;
++	struct inode *h_inode;
++
++	h_dentry = au_h_dptr(dentry, bindex);
++	h_inode = h_dentry->d_inode;
++	if (!dentry->d_inode) {
++		err = -EEXIST;
++		if (unlikely(h_inode))
++			goto out;
++	} else {
++		/* rename(2) case */
++		err = -EIO;
++		if (unlikely(!h_inode || !h_inode->i_nlink))
++			goto out;
++
++		h_mode = h_inode->i_mode;
++		if (!isdir) {
++			err = -EISDIR;
++			if (unlikely(S_ISDIR(h_mode)))
++				goto out;
++		} else if (unlikely(!S_ISDIR(h_mode))) {
++			err = -ENOTDIR;
++			goto out;
++		}
++	}
++
++	err = -EIO;
++	/* expected parent dir is locked */
++	if (unlikely(h_parent != h_dentry->d_parent))
++		goto out;
++	err = 0;
++
++ out:
++	return err;
++}
++
++/*
++ * initial procedure of adding a new entry.
++ * prepare writable branch and the parent dir, lock it,
++ * and lookup whiteout for the new entry.
++ */
++static struct dentry*
++lock_hdir_lkup_wh(struct dentry *dentry, struct au_dtime *dt,
++		  struct dentry *src_dentry, struct au_pin *pin,
++		  struct au_wr_dir_args *wr_dir_args)
++{
++	struct dentry *wh_dentry, *h_parent;
++	struct super_block *sb;
++	struct au_branch *br;
++	int err;
++	unsigned int udba;
++	aufs_bindex_t bcpup;
++
++	err = au_wr_dir(dentry, src_dentry, wr_dir_args);
++	bcpup = err;
++	wh_dentry = ERR_PTR(err);
++	if (unlikely(err < 0))
++		goto out;
++
++	sb = dentry->d_sb;
++	udba = au_opt_udba(sb);
++	err = au_pin(pin, dentry, bcpup, udba,
++		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++	wh_dentry = ERR_PTR(err);
++	if (unlikely(err))
++		goto out;
++
++	h_parent = au_pinned_h_parent(pin);
++	if (udba != AuOpt_UDBA_NONE
++	    && au_dbstart(dentry) == bcpup) {
++		err = au_may_add(dentry, bcpup, h_parent,
++				 au_ftest_wrdir(wr_dir_args->flags, ISDIR));
++		wh_dentry = ERR_PTR(err);
++		if (unlikely(err))
++			goto out_unpin;
++	}
++
++	br = au_sbr(sb, bcpup);
++	if (dt) {
++		struct path tmp = {
++			.dentry	= h_parent,
++			.mnt	= br->br_mnt
++		};
++		au_dtime_store(dt, au_pinned_parent(pin), &tmp);
++	}
++
++	wh_dentry = NULL;
++	if (bcpup != au_dbwh(dentry))
++		goto out; /* success */
++
++	wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, br);
++
++ out_unpin:
++	if (IS_ERR(wh_dentry))
++		au_unpin(pin);
++ out:
++	return wh_dentry;
++}
++
++/* ---------------------------------------------------------------------- */
++
++enum { Mknod, Symlink, Creat };
++struct simple_arg {
++	int type;
++	union {
++		struct {
++			int mode;
++			struct nameidata *nd;
++		} c;
++		struct {
++			const char *symname;
++		} s;
++		struct {
++			int mode;
++			dev_t dev;
++		} m;
++	} u;
++};
++
++static int add_simple(struct inode *dir, struct dentry *dentry,
++		      struct simple_arg *arg)
++{
++	int err;
++	aufs_bindex_t bstart;
++	unsigned char created;
++	struct au_dtime dt;
++	struct au_pin pin;
++	struct path h_path;
++	struct dentry *wh_dentry, *parent;
++	struct inode *h_dir;
++	struct au_wr_dir_args wr_dir_args = {
++		.force_btgt	= -1,
++		.flags		= AuWrDir_ADD_ENTRY
++	};
++
++	IMustLock(dir);
++
++	parent = dentry->d_parent; /* dir inode is locked */
++	aufs_read_lock(dentry, AuLock_DW);
++	di_write_lock_parent(parent);
++	wh_dentry = lock_hdir_lkup_wh(dentry, &dt, /*src_dentry*/NULL, &pin,
++				      &wr_dir_args);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out;
++
++	bstart = au_dbstart(dentry);
++	h_path.dentry = au_h_dptr(dentry, bstart);
++	h_path.mnt = au_sbr_mnt(dentry->d_sb, bstart);
++	h_dir = au_pinned_h_dir(&pin);
++	switch (arg->type) {
++	case Creat:
++		err = vfsub_create(h_dir, &h_path, arg->u.c.mode);
++		break;
++	case Symlink:
++		err = vfsub_symlink(h_dir, &h_path, arg->u.s.symname);
++		break;
++	case Mknod:
++		err = vfsub_mknod(h_dir, &h_path, arg->u.m.mode, arg->u.m.dev);
++		break;
++	default:
++		BUG();
++	}
++	created = !err;
++	if (!err)
++		err = epilog(dir, bstart, wh_dentry, dentry);
++
++	/* revert */
++	if (unlikely(created && err && h_path.dentry->d_inode)) {
++		int rerr;
++		rerr = vfsub_unlink(h_dir, &h_path, /*force*/0);
++		if (rerr) {
++			AuIOErr("%.*s revert failure(%d, %d)\n",
++				AuDLNPair(dentry), err, rerr);
++			err = -EIO;
++		}
++		au_dtime_revert(&dt);
++		d_drop(dentry);
++	}
++
++	au_unpin(&pin);
++	dput(wh_dentry);
++
++ out:
++	if (unlikely(err)) {
++		au_update_dbstart(dentry);
++		d_drop(dentry);
++	}
++	di_write_unlock(parent);
++	aufs_read_unlock(dentry, AuLock_DW);
++	return err;
++}
++
++int aufs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
++{
++	struct simple_arg arg = {
++		.type = Mknod,
++		.u.m = {
++			.mode	= mode,
++			.dev	= dev
++		}
++	};
++	return add_simple(dir, dentry, &arg);
++}
++
++int aufs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
++{
++	struct simple_arg arg = {
++		.type = Symlink,
++		.u.s.symname = symname
++	};
++	return add_simple(dir, dentry, &arg);
++}
++
++int aufs_create(struct inode *dir, struct dentry *dentry, int mode,
++		struct nameidata *nd)
++{
++	struct simple_arg arg = {
++		.type = Creat,
++		.u.c = {
++			.mode	= mode,
++			.nd	= nd
++		}
++	};
++	return add_simple(dir, dentry, &arg);
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct au_link_args {
++	aufs_bindex_t bdst, bsrc;
++	struct au_pin pin;
++	struct path h_path;
++	struct dentry *src_parent, *parent;
++};
++
++static int au_cpup_before_link(struct dentry *src_dentry,
++			       struct au_link_args *a)
++{
++	int err;
++	struct dentry *h_src_dentry;
++	struct mutex *h_mtx;
++
++	di_read_lock_parent(a->src_parent, AuLock_IR);
++	err = au_test_and_cpup_dirs(src_dentry, a->bdst);
++	if (unlikely(err))
++		goto out;
++
++	h_src_dentry = au_h_dptr(src_dentry, a->bsrc);
++	h_mtx = &h_src_dentry->d_inode->i_mutex;
++	err = au_pin(&a->pin, src_dentry, a->bdst,
++		     au_opt_udba(src_dentry->d_sb),
++		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++	if (unlikely(err))
++		goto out;
++	mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++	err = au_sio_cpup_simple(src_dentry, a->bdst, -1,
++				 AuCpup_DTIME /* | AuCpup_KEEPLINO */);
++	mutex_unlock(h_mtx);
++	au_unpin(&a->pin);
++
++ out:
++	di_read_unlock(a->src_parent, AuLock_IR);
++	return err;
++}
++
++static int au_cpup_or_link(struct dentry *src_dentry, struct au_link_args *a)
++{
++	int err;
++	unsigned char plink;
++	struct inode *h_inode, *inode;
++	struct dentry *h_src_dentry;
++	struct super_block *sb;
++
++	plink = 0;
++	h_inode = NULL;
++	sb = src_dentry->d_sb;
++	inode = src_dentry->d_inode;
++	if (au_ibstart(inode) <= a->bdst)
++		h_inode = au_h_iptr(inode, a->bdst);
++	if (!h_inode || !h_inode->i_nlink) {
++		/* copyup src_dentry as the name of dentry. */
++		au_set_dbstart(src_dentry, a->bdst);
++		au_set_h_dptr(src_dentry, a->bdst, dget(a->h_path.dentry));
++		h_inode = au_h_dptr(src_dentry, a->bsrc)->d_inode;
++		mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++		err = au_sio_cpup_single(src_dentry, a->bdst, a->bsrc, -1,
++					 AuCpup_KEEPLINO, a->parent);
++		mutex_unlock(&h_inode->i_mutex);
++		au_set_h_dptr(src_dentry, a->bdst, NULL);
++		au_set_dbstart(src_dentry, a->bsrc);
++	} else {
++		/* the inode of src_dentry already exists on a.bdst branch */
++		h_src_dentry = d_find_alias(h_inode);
++		if (!h_src_dentry && au_plink_test(inode)) {
++			plink = 1;
++			h_src_dentry = au_plink_lkup(inode, a->bdst);
++			err = PTR_ERR(h_src_dentry);
++			if (IS_ERR(h_src_dentry))
++				goto out;
++
++			if (unlikely(!h_src_dentry->d_inode)) {
++				dput(h_src_dentry);
++				h_src_dentry = NULL;
++			}
++
++		}
++		if (h_src_dentry) {
++			err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
++					 &a->h_path);
++			dput(h_src_dentry);
++		} else {
++			AuIOErr("no dentry found for hi%lu on b%d\n",
++				h_inode->i_ino, a->bdst);
++			err = -EIO;
++		}
++	}
++
++	if (!err && !plink)
++		au_plink_append(inode, a->bdst, a->h_path.dentry);
++
++out:
++	return err;
++}
++
++int aufs_link(struct dentry *src_dentry, struct inode *dir,
++	      struct dentry *dentry)
++{
++	int err, rerr;
++	struct au_dtime dt;
++	struct au_link_args *a;
++	struct dentry *wh_dentry, *h_src_dentry;
++	struct inode *inode;
++	struct super_block *sb;
++	struct au_wr_dir_args wr_dir_args = {
++		/* .force_btgt	= -1, */
++		.flags		= AuWrDir_ADD_ENTRY
++	};
++
++	IMustLock(dir);
++	inode = src_dentry->d_inode;
++	IMustLock(inode);
++
++	err = -ENOMEM;
++	a = kzalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	a->parent = dentry->d_parent; /* dir inode is locked */
++	aufs_read_and_write_lock2(dentry, src_dentry, /*AuLock_FLUSH*/0);
++	a->src_parent = dget_parent(src_dentry);
++	wr_dir_args.force_btgt = au_dbstart(src_dentry);
++
++	di_write_lock_parent(a->parent);
++	wr_dir_args.force_btgt = au_wbr(dentry, wr_dir_args.force_btgt);
++	wh_dentry = lock_hdir_lkup_wh(dentry, &dt, src_dentry, &a->pin,
++				      &wr_dir_args);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out_unlock;
++
++	err = 0;
++	sb = dentry->d_sb;
++	a->bdst = au_dbstart(dentry);
++	a->h_path.dentry = au_h_dptr(dentry, a->bdst);
++	a->h_path.mnt = au_sbr_mnt(sb, a->bdst);
++	a->bsrc = au_dbstart(src_dentry);
++	if (au_opt_test(au_mntflags(sb), PLINK)) {
++		if (a->bdst < a->bsrc
++		    /* && h_src_dentry->d_sb != a->h_path.dentry->d_sb */)
++			err = au_cpup_or_link(src_dentry, a);
++		else {
++			h_src_dentry = au_h_dptr(src_dentry, a->bdst);
++			err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
++					 &a->h_path);
++		}
++	} else {
++		/*
++		 * copyup src_dentry to the branch we process,
++		 * and then link(2) to it.
++		 */
++		if (a->bdst < a->bsrc
++		    /* && h_src_dentry->d_sb != a->h_path.dentry->d_sb */) {
++			au_unpin(&a->pin);
++			di_write_unlock(a->parent);
++			err = au_cpup_before_link(src_dentry, a);
++			if (!err) {
++				di_write_lock_parent(a->parent);
++				err = au_pin(&a->pin, dentry, a->bdst,
++					     au_opt_udba(sb),
++					     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++				if (unlikely(err))
++					goto out_wh;
++			}
++		}
++		if (!err) {
++			h_src_dentry = au_h_dptr(src_dentry, a->bdst);
++			err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
++					 &a->h_path);
++		}
++	}
++	if (unlikely(err))
++		goto out_unpin;
++
++	if (wh_dentry) {
++		a->h_path.dentry = wh_dentry;
++		err = au_wh_unlink_dentry(au_pinned_h_dir(&a->pin), &a->h_path,
++					  dentry);
++		if (unlikely(err))
++			goto out_revert;
++	}
++
++	dir->i_version++;
++	if (au_ibstart(dir) == au_dbstart(dentry))
++		au_cpup_attr_timesizes(dir);
++	inc_nlink(inode);
++	inode->i_ctime = dir->i_ctime;
++	if (!d_unhashed(a->h_path.dentry))
++		d_instantiate(dentry, au_igrab(inode));
++	else
++		/* some filesystem calls d_drop() */
++		d_drop(dentry);
++	goto out_unpin; /* success */
++
++ out_revert:
++	rerr = vfsub_unlink(au_pinned_h_dir(&a->pin), &a->h_path, /*force*/0);
++	if (!rerr)
++		goto out_dt;
++	AuIOErr("%.*s reverting failed(%d, %d)\n",
++		AuDLNPair(dentry), err, rerr);
++	err = -EIO;
++ out_dt:
++	d_drop(dentry);
++	au_dtime_revert(&dt);
++ out_unpin:
++	au_unpin(&a->pin);
++ out_wh:
++	dput(wh_dentry);
++ out_unlock:
++	if (unlikely(err)) {
++		au_update_dbstart(dentry);
++		d_drop(dentry);
++	}
++	di_write_unlock(a->parent);
++	dput(a->src_parent);
++	aufs_read_and_write_unlock2(dentry, src_dentry);
++	kfree(a);
++ out:
++	return err;
++}
++
++int aufs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
++{
++	int err, rerr;
++	aufs_bindex_t bindex;
++	unsigned char diropq;
++	struct au_pin pin;
++	struct path h_path;
++	struct dentry *wh_dentry, *parent, *opq_dentry;
++	struct mutex *h_mtx;
++	struct super_block *sb;
++	struct au_dtime dt;
++	struct au_wr_dir_args wr_dir_args = {
++		.force_btgt	= -1,
++		.flags		= AuWrDir_ADD_ENTRY | AuWrDir_ISDIR
++	};
++
++	IMustLock(dir);
++
++	aufs_read_lock(dentry, AuLock_DW);
++	parent = dentry->d_parent; /* dir inode is locked */
++	di_write_lock_parent(parent);
++	wh_dentry = lock_hdir_lkup_wh(dentry, &dt, /*src_dentry*/NULL, &pin,
++				      &wr_dir_args);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out;
++
++	sb = dentry->d_sb;
++	bindex = au_dbstart(dentry);
++	h_path.dentry = au_h_dptr(dentry, bindex);
++	h_path.mnt = au_sbr_mnt(sb, bindex);
++	err = vfsub_mkdir(au_pinned_h_dir(&pin), &h_path, mode);
++	if (unlikely(err))
++		goto out_unlock;
++
++	/* make the dir opaque */
++	diropq = 0;
++	h_mtx = &h_path.dentry->d_inode->i_mutex;
++	if (wh_dentry
++	    || au_opt_test(au_mntflags(sb), ALWAYS_DIROPQ)) {
++		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++		opq_dentry = au_diropq_create(dentry, bindex);
++		mutex_unlock(h_mtx);
++		err = PTR_ERR(opq_dentry);
++		if (IS_ERR(opq_dentry))
++			goto out_dir;
++		dput(opq_dentry);
++		diropq = 1;
++	}
++
++	err = epilog(dir, bindex, wh_dentry, dentry);
++	if (!err) {
++		inc_nlink(dir);
++		goto out_unlock; /* success */
++	}
++
++	/* revert */
++	if (diropq) {
++		AuLabel(revert opq);
++		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++		rerr = au_diropq_remove(dentry, bindex);
++		mutex_unlock(h_mtx);
++		if (rerr) {
++			AuIOErr("%.*s reverting diropq failed(%d, %d)\n",
++				AuDLNPair(dentry), err, rerr);
++			err = -EIO;
++		}
++	}
++
++ out_dir:
++	AuLabel(revert dir);
++	rerr = vfsub_rmdir(au_pinned_h_dir(&pin), &h_path);
++	if (rerr) {
++		AuIOErr("%.*s reverting dir failed(%d, %d)\n",
++			AuDLNPair(dentry), err, rerr);
++		err = -EIO;
++	}
++	d_drop(dentry);
++	au_dtime_revert(&dt);
++ out_unlock:
++	au_unpin(&pin);
++	dput(wh_dentry);
++ out:
++	if (unlikely(err)) {
++		au_update_dbstart(dentry);
++		d_drop(dentry);
++	}
++	di_write_unlock(parent);
++	aufs_read_unlock(dentry, AuLock_DW);
++	return err;
++}
+diff -uNr test/fs/aufs/i_op_del.c aufs2-standalone/fs/aufs/i_op_del.c
+--- test/fs/aufs/i_op_del.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/i_op_del.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,471 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * inode operations (del entry)
++ */
++
++#include "aufs.h"
++
++/*
++ * decide if a new whiteout for @dentry is necessary or not.
++ * when it is necessary, prepare the parent dir for the upper branch whose
++ * branch index is @bcpup for creation. the actual creation of the whiteout will
++ * be done by caller.
++ * return value:
++ * 0: wh is unnecessary
++ * plus: wh is necessary
++ * minus: error
++ */
++int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup)
++{
++	int need_wh, err;
++	aufs_bindex_t bstart;
++	struct super_block *sb;
++
++	sb = dentry->d_sb;
++	bstart = au_dbstart(dentry);
++	if (*bcpup < 0) {
++		*bcpup = bstart;
++		if (au_test_ro(sb, bstart, dentry->d_inode)) {
++			err = AuWbrCopyup(au_sbi(sb), dentry);
++			*bcpup = err;
++			if (unlikely(err < 0))
++				goto out;
++		}
++	} else
++		AuDebugOn(bstart < *bcpup
++			  || au_test_ro(sb, *bcpup, dentry->d_inode));
++	AuDbg("bcpup %d, bstart %d\n", *bcpup, bstart);
++
++	if (*bcpup != bstart) {
++		err = au_cpup_dirs(dentry, *bcpup);
++		if (unlikely(err))
++			goto out;
++		need_wh = 1;
++	} else {
++		aufs_bindex_t old_bend, new_bend, bdiropq = -1;
++
++		old_bend = au_dbend(dentry);
++		if (isdir) {
++			bdiropq = au_dbdiropq(dentry);
++			au_set_dbdiropq(dentry, -1);
++		}
++		need_wh = au_lkup_dentry(dentry, bstart + 1, /*type*/0,
++					 /*nd*/NULL);
++		err = need_wh;
++		if (isdir)
++			au_set_dbdiropq(dentry, bdiropq);
++		if (unlikely(err < 0))
++			goto out;
++		new_bend = au_dbend(dentry);
++		if (!need_wh && old_bend != new_bend) {
++			au_set_h_dptr(dentry, new_bend, NULL);
++			au_set_dbend(dentry, old_bend);
++		}
++	}
++	AuDbg("need_wh %d\n", need_wh);
++	err = need_wh;
++
++ out:
++	return err;
++}
++
++/*
++ * simple tests for the del-entry operations.
++ * following the checks in vfs, plus the parent-child relationship.
++ */
++int au_may_del(struct dentry *dentry, aufs_bindex_t bindex,
++	       struct dentry *h_parent, int isdir)
++{
++	int err;
++	umode_t h_mode;
++	struct dentry *h_dentry, *h_latest;
++	struct inode *h_inode;
++
++	h_dentry = au_h_dptr(dentry, bindex);
++	h_inode = h_dentry->d_inode;
++	if (dentry->d_inode) {
++		err = -ENOENT;
++		if (unlikely(!h_inode || !h_inode->i_nlink))
++			goto out;
++
++		h_mode = h_inode->i_mode;
++		if (!isdir) {
++			err = -EISDIR;
++			if (unlikely(S_ISDIR(h_mode)))
++				goto out;
++		} else if (unlikely(!S_ISDIR(h_mode))) {
++			err = -ENOTDIR;
++			goto out;
++		}
++	} else {
++		/* rename(2) case */
++		err = -EIO;
++		if (unlikely(h_inode))
++			goto out;
++	}
++
++	err = -ENOENT;
++	/* expected parent dir is locked */
++	if (unlikely(h_parent != h_dentry->d_parent))
++		goto out;
++	err = 0;
++
++	/*
++	 * rmdir a dir may break the consistency on some filesystem.
++	 * let's try heavy test.
++	 */
++	err = -EACCES;
++	if (unlikely(au_test_h_perm(h_parent->d_inode, MAY_EXEC | MAY_WRITE)))
++		goto out;
++
++	h_latest = au_sio_lkup_one(&dentry->d_name, h_parent,
++				   au_sbr(dentry->d_sb, bindex));
++	err = -EIO;
++	if (IS_ERR(h_latest))
++		goto out;
++	if (h_latest == h_dentry)
++		err = 0;
++	dput(h_latest);
++
++ out:
++	return err;
++}
++
++/*
++ * decide the branch where we operate for @dentry. the branch index will be set
++ * @rbcpup. after diciding it, 'pin' it and store the timestamps of the parent
++ * dir for reverting.
++ * when a new whiteout is necessary, create it.
++ */
++static struct dentry*
++lock_hdir_create_wh(struct dentry *dentry, int isdir, aufs_bindex_t *rbcpup,
++		    struct au_dtime *dt, struct au_pin *pin)
++{
++	struct dentry *wh_dentry;
++	struct super_block *sb;
++	struct path h_path;
++	int err, need_wh;
++	unsigned int udba;
++	aufs_bindex_t bcpup;
++
++	need_wh = au_wr_dir_need_wh(dentry, isdir, rbcpup);
++	wh_dentry = ERR_PTR(need_wh);
++	if (unlikely(need_wh < 0))
++		goto out;
++
++	sb = dentry->d_sb;
++	udba = au_opt_udba(sb);
++	bcpup = *rbcpup;
++	err = au_pin(pin, dentry, bcpup, udba,
++		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++	wh_dentry = ERR_PTR(err);
++	if (unlikely(err))
++		goto out;
++
++	h_path.dentry = au_pinned_h_parent(pin);
++	if (udba != AuOpt_UDBA_NONE
++	    && au_dbstart(dentry) == bcpup) {
++		err = au_may_del(dentry, bcpup, h_path.dentry, isdir);
++		wh_dentry = ERR_PTR(err);
++		if (unlikely(err))
++			goto out_unpin;
++	}
++
++	h_path.mnt = au_sbr_mnt(sb, bcpup);
++	au_dtime_store(dt, au_pinned_parent(pin), &h_path);
++	wh_dentry = NULL;
++	if (!need_wh)
++		goto out; /* success, no need to create whiteout */
++
++	wh_dentry = au_wh_create(dentry, bcpup, h_path.dentry);
++	if (!IS_ERR(wh_dentry))
++		goto out; /* success */
++	/* returns with the parent is locked and wh_dentry is dget-ed */
++
++ out_unpin:
++	au_unpin(pin);
++ out:
++	return wh_dentry;
++}
++
++/*
++ * when removing a dir, rename it to a unique temporary whiteout-ed name first
++ * in order to be revertible and save time for removing many child whiteouts
++ * under the dir.
++ * returns 1 when there are too many child whiteout and caller should remove
++ * them asynchronously. returns 0 when the number of children is enough small to
++ * remove now or the branch fs is a remote fs.
++ * otherwise return an error.
++ */
++static int renwh_and_rmdir(struct dentry *dentry, aufs_bindex_t bindex,
++			   struct au_nhash *whlist, struct inode *dir)
++{
++	int rmdir_later, err, dirwh;
++	struct dentry *h_dentry;
++	struct super_block *sb;
++
++	sb = dentry->d_sb;
++	h_dentry = au_h_dptr(dentry, bindex);
++	err = au_whtmp_ren(h_dentry, au_sbr(sb, bindex));
++	if (unlikely(err))
++		goto out;
++
++	/* stop monitoring */
++	au_hin_free(au_hi(dentry->d_inode, bindex));
++
++	if (!au_test_fs_remote(h_dentry->d_sb)) {
++		dirwh = au_sbi(sb)->si_dirwh;
++		rmdir_later = (dirwh <= 1);
++		if (!rmdir_later)
++			rmdir_later = au_nhash_test_longer_wh(whlist, bindex,
++							      dirwh);
++		if (rmdir_later)
++			return rmdir_later;
++	}
++
++	err = au_whtmp_rmdir(dir, bindex, h_dentry, whlist);
++	if (unlikely(err)) {
++		AuIOErr("rmdir %.*s, b%d failed, %d. ignored\n",
++			AuDLNPair(h_dentry), bindex, err);
++		err = 0;
++	}
++
++ out:
++	return err;
++}
++
++/*
++ * final procedure for deleting a entry.
++ * maintain dentry and iattr.
++ */
++static void epilog(struct inode *dir, struct dentry *dentry,
++		   aufs_bindex_t bindex)
++{
++	struct inode *inode;
++
++	/*
++	 * even if this is not a dir,
++	 * set S_DEAD here since we need to detect the dead inode.
++	 */
++	inode = dentry->d_inode;
++	if (!inode->i_nlink)
++		inode->i_flags |= S_DEAD;
++	d_drop(dentry);
++	inode->i_ctime = dir->i_ctime;
++
++	if (atomic_read(&dentry->d_count) == 1) {
++		au_set_h_dptr(dentry, au_dbstart(dentry), NULL);
++		au_update_dbstart(dentry);
++	}
++	if (au_ibstart(dir) == bindex)
++		au_cpup_attr_timesizes(dir);
++	dir->i_version++;
++}
++
++/*
++ * when an error happened, remove the created whiteout and revert everything.
++ */
++static int do_revert(int err, struct inode *dir, aufs_bindex_t bwh,
++		     struct dentry *wh_dentry, struct dentry *dentry,
++		     struct au_dtime *dt)
++{
++	int rerr;
++	struct path h_path = {
++		.dentry	= wh_dentry,
++		.mnt	= au_sbr_mnt(dir->i_sb, bwh)
++	};
++
++	rerr = au_wh_unlink_dentry(au_h_iptr(dir, bwh), &h_path, dentry);
++	if (!rerr) {
++		au_set_dbwh(dentry, bwh);
++		au_dtime_revert(dt);
++		return 0;
++	}
++
++	AuIOErr("%.*s reverting whiteout failed(%d, %d)\n",
++		AuDLNPair(dentry), err, rerr);
++	return -EIO;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int aufs_unlink(struct inode *dir, struct dentry *dentry)
++{
++	int err;
++	aufs_bindex_t bwh, bindex, bstart;
++	struct au_dtime dt;
++	struct au_pin pin;
++	struct path h_path;
++	struct inode *inode, *h_dir;
++	struct dentry *parent, *wh_dentry;
++
++	IMustLock(dir);
++	inode = dentry->d_inode;
++	if (unlikely(!inode))
++		return -ENOENT; /* possible? */
++	IMustLock(inode);
++
++	aufs_read_lock(dentry, AuLock_DW);
++	parent = dentry->d_parent; /* dir inode is locked */
++	di_write_lock_parent(parent);
++
++	bstart = au_dbstart(dentry);
++	bwh = au_dbwh(dentry);
++	bindex = -1;
++	wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/0, &bindex, &dt, &pin);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out;
++
++	h_path.mnt = au_sbr_mnt(dentry->d_sb, bstart);
++	h_path.dentry = au_h_dptr(dentry, bstart);
++	dget(h_path.dentry);
++	if (bindex == bstart) {
++		h_dir = au_pinned_h_dir(&pin);
++		err = vfsub_unlink(h_dir, &h_path, /*force*/0);
++	} else {
++		/* dir inode is locked */
++		h_dir = wh_dentry->d_parent->d_inode;
++		IMustLock(h_dir);
++		err = 0;
++	}
++
++	if (!err) {
++		drop_nlink(inode);
++		epilog(dir, dentry, bindex);
++
++		/* update target timestamps */
++		if (bindex == bstart) {
++			vfsub_update_h_iattr(&h_path, /*did*/NULL); /*ignore*/
++			inode->i_ctime = h_path.dentry->d_inode->i_ctime;
++		} else
++			/* todo: this timestamp may be reverted later */
++			inode->i_ctime = h_dir->i_ctime;
++		goto out_unlock; /* success */
++	}
++
++	/* revert */
++	if (wh_dentry) {
++		int rerr;
++
++		rerr = do_revert(err, dir, bwh, wh_dentry, dentry, &dt);
++		if (rerr)
++			err = rerr;
++	}
++
++ out_unlock:
++	au_unpin(&pin);
++	dput(wh_dentry);
++	dput(h_path.dentry);
++ out:
++	di_write_unlock(parent);
++	aufs_read_unlock(dentry, AuLock_DW);
++	return err;
++}
++
++int aufs_rmdir(struct inode *dir, struct dentry *dentry)
++{
++	int err, rmdir_later;
++	aufs_bindex_t bwh, bindex, bstart;
++	struct au_dtime dt;
++	struct au_pin pin;
++	struct inode *inode;
++	struct dentry *parent, *wh_dentry, *h_dentry;
++	struct au_whtmp_rmdir_args *args;
++	struct au_nhash *whlist;
++
++	IMustLock(dir);
++	inode = dentry->d_inode;
++	err = -ENOENT; /* possible? */
++	if (unlikely(!inode))
++		goto out;
++	IMustLock(inode);
++
++	whlist = au_nhash_new(GFP_NOFS);
++	err = PTR_ERR(whlist);
++	if (IS_ERR(whlist))
++		goto out;
++
++	err = -ENOMEM;
++	args = kmalloc(sizeof(*args), GFP_NOFS);
++	if (unlikely(!args))
++		goto out_whlist;
++
++	aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH);
++	parent = dentry->d_parent; /* dir inode is locked */
++	di_write_lock_parent(parent);
++	err = au_test_empty(dentry, whlist);
++	if (unlikely(err))
++		goto out_args;
++
++	bstart = au_dbstart(dentry);
++	bwh = au_dbwh(dentry);
++	bindex = -1;
++	wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/1, &bindex, &dt, &pin);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out_args;
++
++	h_dentry = au_h_dptr(dentry, bstart);
++	dget(h_dentry);
++	rmdir_later = 0;
++	if (bindex == bstart) {
++		err = renwh_and_rmdir(dentry, bstart, whlist, dir);
++		if (err > 0) {
++			rmdir_later = err;
++			err = 0;
++		}
++	} else {
++		/* stop monitoring */
++		au_hin_free(au_hi(inode, bstart));
++
++		/* dir inode is locked */
++		IMustLock(wh_dentry->d_parent->d_inode);
++		err = 0;
++	}
++
++	if (!err) {
++		clear_nlink(inode);
++		au_set_dbdiropq(dentry, -1);
++		epilog(dir, dentry, bindex);
++
++		if (rmdir_later) {
++			au_whtmp_kick_rmdir(dir, bstart, h_dentry, whlist,
++					    args);
++			args = NULL;
++		}
++
++		goto out_unlock; /* success */
++	}
++
++	/* revert */
++	AuLabel(revert);
++	if (wh_dentry) {
++		int rerr;
++
++		rerr = do_revert(err, dir, bwh, wh_dentry, dentry, &dt);
++		if (rerr)
++			err = rerr;
++	}
++
++ out_unlock:
++	au_unpin(&pin);
++	dput(wh_dentry);
++	dput(h_dentry);
++ out_args:
++	di_write_unlock(parent);
++	aufs_read_unlock(dentry, AuLock_DW);
++	kfree(args);
++ out_whlist:
++	au_nhash_del(whlist);
++ out:
++	return err;
++}
+diff -uNr test/fs/aufs/i_op_ren.c aufs2-standalone/fs/aufs/i_op_ren.c
+--- test/fs/aufs/i_op_ren.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/i_op_ren.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,929 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * inode operation (rename entry)
++ * todo: this is crazy monster
++ */
++
++#include "aufs.h"
++
++enum { AuSRC, AuDST, AuSrcDst };
++enum { AuPARENT, AuCHILD, AuParentChild };
++
++#define AuRen_ISDIR	1
++#define AuRen_ISSAMEDIR	(1 << 1)
++#define AuRen_WHSRC	(1 << 2)
++#define AuRen_WHDST	(1 << 3)
++#define AuRen_MNT_WRITE	(1 << 4)
++#define AuRen_DT_DSTDIR	(1 << 5)
++#define AuRen_DIROPQ	(1 << 6)
++#define AuRen_CPUP	(1 << 7)
++#define au_ftest_ren(flags, name)	((flags) & AuRen_##name)
++#define au_fset_ren(flags, name)	{ (flags) |= AuRen_##name; }
++#define au_fclr_ren(flags, name)	{ (flags) &= ~AuRen_##name; }
++
++struct au_ren_args {
++	struct {
++		struct dentry *dentry, *h_dentry, *parent, *h_parent,
++			*wh_dentry;
++		struct inode *dir, *inode;
++		struct au_hinode *hdir;
++		struct au_dtime dt[AuParentChild];
++		aufs_bindex_t bstart;
++	} sd[AuSrcDst];
++
++#define src_dentry	sd[AuSRC].dentry
++#define src_dir		sd[AuSRC].dir
++#define src_inode	sd[AuSRC].inode
++#define src_h_dentry	sd[AuSRC].h_dentry
++#define src_parent	sd[AuSRC].parent
++#define src_h_parent	sd[AuSRC].h_parent
++#define src_wh_dentry	sd[AuSRC].wh_dentry
++#define src_hdir	sd[AuSRC].hdir
++#define src_h_dir	sd[AuSRC].hdir->hi_inode
++#define src_dt		sd[AuSRC].dt
++#define src_bstart	sd[AuSRC].bstart
++
++#define dst_dentry	sd[AuDST].dentry
++#define dst_dir		sd[AuDST].dir
++#define dst_inode	sd[AuDST].inode
++#define dst_h_dentry	sd[AuDST].h_dentry
++#define dst_parent	sd[AuDST].parent
++#define dst_h_parent	sd[AuDST].h_parent
++#define dst_wh_dentry	sd[AuDST].wh_dentry
++#define dst_hdir	sd[AuDST].hdir
++#define dst_h_dir	sd[AuDST].hdir->hi_inode
++#define dst_dt		sd[AuDST].dt
++#define dst_bstart	sd[AuDST].bstart
++
++	struct dentry *h_trap;
++	struct au_branch *br;
++	struct au_hinode *src_hinode;
++	struct path h_path;
++	struct au_nhash whlist;
++	aufs_bindex_t btgt;
++
++	unsigned int flags;
++
++	struct au_whtmp_rmdir_args *thargs;
++	struct dentry *h_dst;
++};
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * functions for reverting.
++ * when an error happened in a single rename systemcall, we should revert
++ * everything as if nothing happend.
++ * we don't need to revert the copied-up/down the parent dir since they are
++ * harmless.
++ */
++
++#define RevertFailure(fmt, args...) do { \
++	AuIOErr("revert failure: " fmt " (%d, %d)\n", \
++		##args, err, rerr); \
++	err = -EIO; \
++} while (0)
++
++static void au_ren_rev_diropq(int err, struct au_ren_args *a)
++{
++	int rerr;
++
++	au_hin_imtx_lock_nested(a->src_hinode, AuLsc_I_CHILD);
++	rerr = au_diropq_remove(a->src_dentry, a->btgt);
++	au_hin_imtx_unlock(a->src_hinode);
++	if (rerr)
++		RevertFailure("remove diropq %.*s", AuDLNPair(a->src_dentry));
++}
++
++
++static void au_ren_rev_rename(int err, struct au_ren_args *a)
++{
++	int rerr;
++
++	a->h_path.dentry = au_lkup_one(&a->src_dentry->d_name, a->src_h_parent,
++				       a->br, /*nd*/NULL);
++	rerr = PTR_ERR(a->h_path.dentry);
++	if (IS_ERR(a->h_path.dentry)) {
++		RevertFailure("au_lkup_one %.*s", AuDLNPair(a->src_dentry));
++		return;
++	}
++
++	rerr = vfsub_rename(a->dst_h_dir,
++			    au_h_dptr(a->src_dentry, a->btgt),
++			    a->src_h_dir, &a->h_path);
++	d_drop(a->h_path.dentry);
++	dput(a->h_path.dentry);
++	/* au_set_h_dptr(a->src_dentry, a->btgt, NULL); */
++	if (rerr)
++		RevertFailure("rename %.*s", AuDLNPair(a->src_dentry));
++}
++
++static void au_ren_rev_cpup(int err, struct au_ren_args *a)
++{
++	int rerr;
++
++	a->h_path.dentry = a->dst_h_dentry;
++	rerr = vfsub_unlink(a->dst_h_dir, &a->h_path, /*force*/0);
++	au_set_h_dptr(a->src_dentry, a->btgt, NULL);
++	au_set_dbstart(a->src_dentry, a->src_bstart);
++	if (rerr)
++		RevertFailure("unlink %.*s", AuDLNPair(a->dst_h_dentry));
++}
++
++
++static void au_ren_rev_whtmp(int err, struct au_ren_args *a)
++{
++	int rerr;
++
++	a->h_path.dentry = au_lkup_one(&a->dst_dentry->d_name, a->dst_h_parent,
++				       a->br, /*nd*/NULL);
++	rerr = PTR_ERR(a->h_path.dentry);
++	if (IS_ERR(a->h_path.dentry)) {
++		RevertFailure("lookup %.*s", AuDLNPair(a->dst_dentry));
++		return;
++	}
++	if (a->h_path.dentry->d_inode) {
++		d_drop(a->h_path.dentry);
++		dput(a->h_path.dentry);
++		return;
++	}
++
++	rerr = vfsub_rename(a->dst_h_dir, a->h_dst, a->dst_h_dir, &a->h_path);
++	d_drop(a->h_path.dentry);
++	dput(a->h_path.dentry);
++	if (!rerr) {
++		au_set_h_dptr(a->dst_dentry, a->btgt, NULL);
++		au_set_h_dptr(a->dst_dentry, a->btgt, dget(a->h_dst));
++	} else
++		RevertFailure("rename %.*s", AuDLNPair(a->h_dst));
++}
++
++static void au_ren_rev_whsrc(int err, struct au_ren_args *a)
++{
++	int rerr;
++
++	a->h_path.dentry = a->src_wh_dentry;
++	rerr = au_wh_unlink_dentry(a->src_h_dir, &a->h_path, a->src_dentry);
++	if (rerr)
++		RevertFailure("unlink %.*s", AuDLNPair(a->src_wh_dentry));
++}
++
++static void au_ren_rev_drop(struct au_ren_args *a)
++{
++	struct dentry *d, *h_d;
++	int i;
++	aufs_bindex_t bend, bindex;
++
++	for (i = 0; i < AuSrcDst; i++) {
++		d = a->sd[i].dentry;
++		d_drop(d);
++		bend = au_dbend(d);
++		for (bindex = au_dbstart(d); bindex <= bend; bindex++) {
++			h_d = au_h_dptr(d, bindex);
++			if (h_d)
++				d_drop(h_d);
++		}
++	}
++
++	au_update_dbstart(a->dst_dentry);
++	if (a->thargs)
++		d_drop(a->h_dst);
++}
++#undef RevertFailure
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * when we have to copyup the renaming entry, do it with the rename-target name
++ * in order to minimize the cost (the later actual rename is unnecessary).
++ * otherwise rename it on the target branch.
++ */
++static int au_ren_or_cpup(struct au_ren_args *a)
++{
++	int err;
++	struct dentry *d;
++
++	d = a->src_dentry;
++	if (au_dbstart(d) == a->btgt) {
++		a->h_path.dentry = a->dst_h_dentry;
++		if (au_ftest_ren(a->flags, DIROPQ)
++		    && au_dbdiropq(d) == a->btgt)
++			au_fclr_ren(a->flags, DIROPQ);
++		AuDebugOn(au_dbstart(d) != a->btgt);
++		err = vfsub_rename(a->src_h_dir, au_h_dptr(d, a->btgt),
++				   a->dst_h_dir, &a->h_path);
++	} else {
++		struct mutex *h_mtx = &a->src_h_dentry->d_inode->i_mutex;
++
++		au_fset_ren(a->flags, CPUP);
++		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++		au_set_dbstart(d, a->btgt);
++		au_set_h_dptr(d, a->btgt, dget(a->dst_h_dentry));
++		err = au_sio_cpup_single(d, a->btgt, a->src_bstart, -1,
++					 !AuCpup_DTIME, a->dst_parent);
++		if (unlikely(err)) {
++			au_set_h_dptr(d, a->btgt, NULL);
++			au_set_dbstart(d, a->src_bstart);
++		}
++		mutex_unlock(h_mtx);
++	}
++
++	return err;
++}
++
++/* cf. aufs_rmdir() */
++static int au_ren_del_whtmp(struct au_ren_args *a)
++{
++	int err;
++	struct inode *dir;
++
++	dir = a->dst_dir;
++	if (!au_nhash_test_longer_wh(&a->whlist, a->btgt,
++				     au_sbi(dir->i_sb)->si_dirwh)
++	    || au_test_fs_remote(a->h_dst->d_sb)) {
++		err = au_whtmp_rmdir(dir, a->btgt, a->h_dst, &a->whlist);
++		if (unlikely(err))
++			AuWarn("failed removing whtmp dir %.*s (%d), "
++			       "ignored.\n", AuDLNPair(a->h_dst), err);
++	} else {
++		au_whtmp_kick_rmdir(dir, a->btgt, a->h_dst, &a->whlist,
++				    a->thargs);
++		dput(a->h_dst);
++		a->thargs = NULL;
++	}
++
++	return 0;
++}
++
++/* make it 'opaque' dir. */
++static int au_ren_diropq(struct au_ren_args *a)
++{
++	int err;
++	struct dentry *diropq;
++
++	err = 0;
++	a->src_hinode = au_hi(a->src_inode, a->btgt);
++	au_hin_imtx_lock_nested(a->src_hinode, AuLsc_I_CHILD);
++	diropq = au_diropq_create(a->src_dentry, a->btgt);
++	au_hin_imtx_unlock(a->src_hinode);
++	if (IS_ERR(diropq))
++		err = PTR_ERR(diropq);
++	dput(diropq);
++
++	return err;
++}
++
++static int do_rename(struct au_ren_args *a)
++{
++	int err;
++	struct dentry *d, *h_d;
++
++	/* prepare workqueue args for asynchronous rmdir */
++	h_d = a->dst_h_dentry;
++	if (au_ftest_ren(a->flags, ISDIR) && h_d->d_inode) {
++		err = -ENOMEM;
++		a->thargs = kmalloc(sizeof(*a->thargs), GFP_NOFS);
++		if (unlikely(!a->thargs))
++			goto out;
++		a->h_dst = dget(h_d);
++	}
++
++	/* create whiteout for src_dentry */
++	if (au_ftest_ren(a->flags, WHSRC)) {
++		a->src_wh_dentry
++			= au_wh_create(a->src_dentry, a->btgt, a->src_h_parent);
++		err = PTR_ERR(a->src_wh_dentry);
++		if (IS_ERR(a->src_wh_dentry))
++			goto out_thargs;
++	}
++
++	/* lookup whiteout for dentry */
++	if (au_ftest_ren(a->flags, WHDST)) {
++		h_d = au_wh_lkup(a->dst_h_parent, &a->dst_dentry->d_name,
++				 a->br);
++		err = PTR_ERR(h_d);
++		if (IS_ERR(h_d))
++			goto out_whsrc;
++		if (!h_d->d_inode)
++			dput(h_d);
++		else
++			a->dst_wh_dentry = h_d;
++	}
++
++	/* rename dentry to tmpwh */
++	if (a->thargs) {
++		err = au_whtmp_ren(a->dst_h_dentry, a->br);
++		if (unlikely(err))
++			goto out_whdst;
++
++		d = a->dst_dentry;
++		au_set_h_dptr(d, a->btgt, NULL);
++		err = au_lkup_neg(d, a->btgt);
++		if (unlikely(err))
++			goto out_whtmp;
++		a->dst_h_dentry = au_h_dptr(d, a->btgt);
++	}
++
++	/* cpup src */
++	if (a->dst_h_dentry->d_inode && a->src_bstart != a->btgt) {
++		struct mutex *h_mtx = &a->src_h_dentry->d_inode->i_mutex;
++
++		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++		err = au_sio_cpup_simple(a->src_dentry, a->btgt, -1,
++					 !AuCpup_DTIME);
++		mutex_unlock(h_mtx);
++		if (unlikely(err))
++			goto out_whtmp;
++	}
++
++	/* rename by vfs_rename or cpup */
++	d = a->dst_dentry;
++	if (au_ftest_ren(a->flags, ISDIR)
++	    && (a->dst_wh_dentry
++		|| au_dbdiropq(d) == a->btgt
++		/* hide the lower to keep xino */
++		|| a->btgt < au_dbend(d)
++		|| au_opt_test(au_mntflags(d->d_sb), ALWAYS_DIROPQ)))
++		au_fset_ren(a->flags, DIROPQ);
++	err = au_ren_or_cpup(a);
++	if (unlikely(err))
++		/* leave the copied-up one */
++		goto out_whtmp;
++
++	/* make dir opaque */
++	if (au_ftest_ren(a->flags, DIROPQ)) {
++		err = au_ren_diropq(a);
++		if (unlikely(err))
++			goto out_rename;
++	}
++
++	/* update target timestamps */
++	AuDebugOn(au_dbstart(a->src_dentry) != a->btgt);
++	a->h_path.dentry = au_h_dptr(a->src_dentry, a->btgt);
++	vfsub_update_h_iattr(&a->h_path, /*did*/NULL); /*ignore*/
++	a->src_inode->i_ctime = a->h_path.dentry->d_inode->i_ctime;
++
++	/* remove whiteout for dentry */
++	if (a->dst_wh_dentry) {
++		a->h_path.dentry = a->dst_wh_dentry;
++		err = au_wh_unlink_dentry(a->dst_h_dir, &a->h_path,
++					  a->dst_dentry);
++		if (unlikely(err))
++			goto out_diropq;
++	}
++
++	/* remove whtmp */
++	if (a->thargs)
++		au_ren_del_whtmp(a); /* ignore this error */
++
++	err = 0;
++	goto out_success;
++
++ out_diropq:
++	if (au_ftest_ren(a->flags, DIROPQ))
++		au_ren_rev_diropq(err, a);
++ out_rename:
++	if (!au_ftest_ren(a->flags, CPUP))
++		au_ren_rev_rename(err, a);
++	else
++		au_ren_rev_cpup(err, a);
++ out_whtmp:
++	if (a->thargs)
++		au_ren_rev_whtmp(err, a);
++ out_whdst:
++	dput(a->dst_wh_dentry);
++	a->dst_wh_dentry = NULL;
++ out_whsrc:
++	if (a->src_wh_dentry)
++		au_ren_rev_whsrc(err, a);
++	au_ren_rev_drop(a);
++ out_success:
++	dput(a->src_wh_dentry);
++	dput(a->dst_wh_dentry);
++ out_thargs:
++	if (a->thargs) {
++		dput(a->h_dst);
++		kfree(a->thargs);
++	}
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * test if @dentry dir can be rename destination or not.
++ * success means, it is a logically empty dir.
++ */
++static int may_rename_dstdir(struct dentry *dentry, struct au_nhash *whlist)
++{
++	return au_test_empty(dentry, whlist);
++}
++
++/*
++ * test if @dentry dir can be rename source or not.
++ * if it can, return 0 and @children is filled.
++ * success means,
++ * - it is a logically empty dir.
++ * - or, it exists on writable branch and has no children including whiteouts
++ *       on the lower branch.
++ */
++static int may_rename_srcdir(struct dentry *dentry, aufs_bindex_t btgt)
++{
++	int err;
++	aufs_bindex_t bstart;
++
++	bstart = au_dbstart(dentry);
++	if (bstart != btgt) {
++		struct au_nhash *whlist;
++
++		whlist = au_nhash_new(GFP_NOFS);
++		err = PTR_ERR(whlist);
++		if (IS_ERR(whlist))
++			goto out;
++		err = au_test_empty(dentry, whlist);
++		au_nhash_del(whlist);
++		goto out;
++	}
++
++	if (bstart == au_dbtaildir(dentry))
++		return 0; /* success */
++
++	err = au_test_empty_lower(dentry);
++
++ out:
++	if (err == -ENOTEMPTY) {
++		AuWarn1("renaming dir who has child(ren) on multiple branches,"
++			" is not supported\n");
++		err = -EXDEV;
++	}
++	return err;
++}
++
++/* side effect: sets whlist and h_dentry */
++static int au_ren_may_dir(struct au_ren_args *a)
++{
++	int err;
++	struct dentry *d;
++
++	err = 0;
++	au_nhash_init(&a->whlist);
++	d = a->dst_dentry;
++	if (au_ftest_ren(a->flags, ISDIR) && a->dst_inode) {
++		au_set_dbstart(d, a->dst_bstart);
++		err = may_rename_dstdir(d, &a->whlist);
++		au_set_dbstart(d, a->btgt);
++	}
++	a->dst_h_dentry = au_h_dptr(d, au_dbstart(d));
++	if (unlikely(err))
++		goto out;
++
++	d = a->src_dentry;
++	a->src_h_dentry = au_h_dptr(d, au_dbstart(d));
++	if (au_ftest_ren(a->flags, ISDIR)) {
++		err = may_rename_srcdir(d, a->btgt);
++		if (unlikely(err))
++			au_nhash_fin(&a->whlist);
++	}
++
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * simple tests for rename.
++ * following the checks in vfs, plus the parent-child relationship.
++ */
++static int au_may_ren(struct au_ren_args *a)
++{
++	int err, isdir;
++	struct inode *h_inode;
++
++	if (a->src_bstart == a->btgt) {
++		err = au_may_del(a->src_dentry, a->btgt, a->src_h_parent,
++				 au_ftest_ren(a->flags, ISDIR));
++		if (unlikely(err))
++			goto out;
++		err = -EINVAL;
++		if (unlikely(a->src_h_dentry == a->h_trap))
++			goto out;
++	}
++
++	err = 0;
++	if (a->dst_bstart != a->btgt)
++		goto out;
++
++	err = -EIO;
++	h_inode = a->dst_h_dentry->d_inode;
++	isdir = !!au_ftest_ren(a->flags, ISDIR);
++	if (!a->dst_dentry->d_inode) {
++		if (unlikely(h_inode))
++			goto out;
++		err = au_may_add(a->dst_dentry, a->btgt, a->dst_h_parent,
++				 isdir);
++	} else {
++		if (unlikely(!h_inode || !h_inode->i_nlink))
++			goto out;
++		err = au_may_del(a->dst_dentry, a->btgt, a->dst_h_parent,
++				 isdir);
++		if (unlikely(err))
++			goto out;
++		err = -ENOTEMPTY;
++		if (unlikely(a->dst_h_dentry == a->h_trap))
++			goto out;
++		err = 0;
++	}
++
++ out:
++	if (unlikely(err == -ENOENT || err == -EEXIST))
++		err = -EIO;
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * locking order
++ * (VFS)
++ * - src_dir and dir by lock_rename()
++ * - inode if exitsts
++ * (aufs)
++ * - lock all
++ *   + src_dentry and dentry by aufs_read_and_write_lock2() which calls,
++ *     + si_read_lock
++ *     + di_write_lock2_child()
++ *       + di_write_lock_child()
++ *	   + ii_write_lock_child()
++ *       + di_write_lock_child2()
++ *	   + ii_write_lock_child2()
++ *     + src_parent and parent
++ *       + di_write_lock_parent()
++ *	   + ii_write_lock_parent()
++ *       + di_write_lock_parent2()
++ *	   + ii_write_lock_parent2()
++ *   + lower src_dir and dir by vfsub_lock_rename()
++ *   + verify the every relationships between child and parent. if any
++ *     of them failed, unlock all and return -EBUSY.
++ */
++static void au_ren_unlock(struct au_ren_args *a)
++{
++	struct super_block *sb;
++
++	sb = a->dst_dentry->d_sb;
++	if (au_ftest_ren(a->flags, MNT_WRITE))
++		mnt_drop_write(a->br->br_mnt);
++	vfsub_unlock_rename(a->src_h_parent, a->src_hdir,
++			    a->dst_h_parent, a->dst_hdir);
++}
++
++static int au_ren_lock(struct au_ren_args *a)
++{
++	int err;
++	unsigned int udba;
++
++	err = 0;
++	a->src_h_parent = au_h_dptr(a->src_parent, a->btgt);
++	a->src_hdir = au_hi(a->src_dir, a->btgt);
++	a->dst_h_parent = au_h_dptr(a->dst_parent, a->btgt);
++	a->dst_hdir = au_hi(a->dst_dir, a->btgt);
++	a->h_trap = vfsub_lock_rename(a->src_h_parent, a->src_hdir,
++				      a->dst_h_parent, a->dst_hdir);
++	udba = au_opt_udba(a->src_dentry->d_sb);
++	if (au_dbstart(a->src_dentry) == a->btgt)
++		err = au_h_verify(a->src_h_dentry, udba,
++				  a->src_h_parent->d_inode, a->src_h_parent,
++				  a->br);
++	if (!err && au_dbstart(a->dst_dentry) == a->btgt)
++		err = au_h_verify(a->dst_h_dentry, udba,
++				  a->dst_h_parent->d_inode, a->dst_h_parent,
++				  a->br);
++	if (!err) {
++		err = mnt_want_write(a->br->br_mnt);
++		if (unlikely(err))
++			goto out_unlock;
++		au_fset_ren(a->flags, MNT_WRITE);
++		goto out; /* success */
++	}
++
++	err = -EBUSY;
++
++ out_unlock:
++	au_ren_unlock(a);
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void au_ren_refresh_dir(struct au_ren_args *a)
++{
++	struct inode *dir;
++
++	dir = a->dst_dir;
++	dir->i_version++;
++	if (au_ftest_ren(a->flags, ISDIR)) {
++		/* is this updating defined in POSIX? */
++		au_cpup_attr_timesizes(a->src_inode);
++		au_cpup_attr_nlink(dir, /*force*/1);
++		if (a->dst_inode) {
++			clear_nlink(a->dst_inode);
++			au_cpup_attr_timesizes(a->dst_inode);
++		}
++	}
++	if (au_ibstart(dir) == a->btgt)
++		au_cpup_attr_timesizes(dir);
++
++	if (au_ftest_ren(a->flags, ISSAMEDIR))
++		return;
++
++	dir = a->src_dir;
++	dir->i_version++;
++	if (au_ftest_ren(a->flags, ISDIR))
++		au_cpup_attr_nlink(dir, /*force*/1);
++	if (au_ibstart(dir) == a->btgt)
++		au_cpup_attr_timesizes(dir);
++}
++
++static void au_ren_refresh(struct au_ren_args *a)
++{
++	aufs_bindex_t bend, bindex;
++	struct dentry *d, *h_d;
++	struct inode *i, *h_i;
++	struct super_block *sb;
++
++	d = a->src_dentry;
++	au_set_dbwh(d, -1);
++	bend = au_dbend(d);
++	for (bindex = a->btgt + 1; bindex <= bend; bindex++) {
++		h_d = au_h_dptr(d, bindex);
++		if (h_d)
++			au_set_h_dptr(d, bindex, NULL);
++	}
++	au_set_dbend(d, a->btgt);
++
++	sb = d->d_sb;
++	i = a->src_inode;
++	if (au_opt_test(au_mntflags(sb), PLINK) && au_plink_test(i))
++		return; /* success */
++
++	bend = au_ibend(i);
++	for (bindex = a->btgt + 1; bindex <= bend; bindex++) {
++		h_i = au_h_iptr(i, bindex);
++		if (h_i) {
++			au_xino_write0(sb, bindex, h_i->i_ino, 0);
++			/* ignore this error */
++			au_set_h_iptr(i, bindex, NULL, 0);
++		}
++	}
++	au_set_ibend(i, a->btgt);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* mainly for link(2) and rename(2) */
++int au_wbr(struct dentry *dentry, aufs_bindex_t btgt)
++{
++	aufs_bindex_t bdiropq, bwh;
++	struct dentry *parent;
++	struct au_branch *br;
++
++	parent = dentry->d_parent;
++	IMustLock(parent->d_inode); /* dir is locked */
++
++	bdiropq = au_dbdiropq(parent);
++	bwh = au_dbwh(dentry);
++	br = au_sbr(dentry->d_sb, btgt);
++	if (au_br_rdonly(br)
++	    || (0 <= bdiropq && bdiropq < btgt)
++	    || (0 <= bwh && bwh < btgt))
++		btgt = -1;
++
++	AuDbg("btgt %d\n", btgt);
++	return btgt;
++}
++
++/* sets src_bstart, dst_bstart and btgt */
++static int au_ren_wbr(struct au_ren_args *a)
++{
++	int err;
++	struct au_wr_dir_args wr_dir_args = {
++		/* .force_btgt	= -1, */
++		.flags		= AuWrDir_ADD_ENTRY
++	};
++
++	a->src_bstart = au_dbstart(a->src_dentry);
++	a->dst_bstart = au_dbstart(a->dst_dentry);
++	if (au_ftest_ren(a->flags, ISDIR))
++		au_fset_wrdir(wr_dir_args.flags, ISDIR);
++	wr_dir_args.force_btgt = a->src_bstart;
++	if (a->dst_inode && a->dst_bstart < a->src_bstart)
++		wr_dir_args.force_btgt = a->dst_bstart;
++	wr_dir_args.force_btgt = au_wbr(a->dst_dentry, wr_dir_args.force_btgt);
++	err = au_wr_dir(a->dst_dentry, a->src_dentry, &wr_dir_args);
++	a->btgt = err;
++
++	return err;
++}
++
++static void au_ren_dt(struct au_ren_args *a)
++{
++	a->h_path.dentry = a->src_h_parent;
++	au_dtime_store(a->src_dt + AuPARENT, a->src_parent, &a->h_path);
++	if (!au_ftest_ren(a->flags, ISSAMEDIR)) {
++		a->h_path.dentry = a->dst_h_parent;
++		au_dtime_store(a->dst_dt + AuPARENT, a->dst_parent, &a->h_path);
++	}
++
++	au_fclr_ren(a->flags, DT_DSTDIR);
++	if (!au_ftest_ren(a->flags, ISDIR))
++		return;
++
++	a->h_path.dentry = a->src_h_dentry;
++	au_dtime_store(a->src_dt + AuCHILD, a->src_dentry, &a->h_path);
++	if (a->dst_h_dentry->d_inode) {
++		au_fset_ren(a->flags, DT_DSTDIR);
++		a->h_path.dentry = a->dst_h_dentry;
++		au_dtime_store(a->dst_dt + AuCHILD, a->dst_dentry, &a->h_path);
++	}
++}
++
++static void au_ren_rev_dt(int err, struct au_ren_args *a)
++{
++	struct dentry *h_d;
++	struct mutex *h_mtx;
++
++	au_dtime_revert(a->src_dt + AuPARENT);
++	if (!au_ftest_ren(a->flags, ISSAMEDIR))
++		au_dtime_revert(a->dst_dt + AuPARENT);
++
++	if (au_ftest_ren(a->flags, ISDIR) && err != -EIO) {
++		h_d = a->src_dt[AuCHILD].dt_h_path.dentry;
++		h_mtx = &h_d->d_inode->i_mutex;
++		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++		au_dtime_revert(a->src_dt + AuCHILD);
++		mutex_unlock(h_mtx);
++
++		if (au_ftest_ren(a->flags, DT_DSTDIR)) {
++			h_d = a->dst_dt[AuCHILD].dt_h_path.dentry;
++			h_mtx = &h_d->d_inode->i_mutex;
++			mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++			au_dtime_revert(a->dst_dt + AuCHILD);
++			mutex_unlock(h_mtx);
++		}
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++int aufs_rename(struct inode *_src_dir, struct dentry *_src_dentry,
++		struct inode *_dst_dir, struct dentry *_dst_dentry)
++{
++	int err;
++	/* reduce stack space */
++	struct au_ren_args *a;
++
++	IMustLock(_src_dir);
++	IMustLock(_dst_dir);
++
++	err = -ENOMEM;
++	BUILD_BUG_ON(sizeof(*a) > PAGE_SIZE);
++	a = kzalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	a->src_dir = _src_dir;
++	a->src_dentry = _src_dentry;
++	a->src_inode = a->src_dentry->d_inode;
++	a->src_parent = a->src_dentry->d_parent; /* dir inode is locked */
++	a->dst_dir = _dst_dir;
++	a->dst_dentry = _dst_dentry;
++	a->dst_inode = a->dst_dentry->d_inode;
++	a->dst_parent = a->dst_dentry->d_parent; /* dir inode is locked */
++	if (a->dst_inode) {
++		IMustLock(a->dst_inode);
++		au_igrab(a->dst_inode);
++	}
++
++	err = -ENOTDIR;
++	if (S_ISDIR(a->src_inode->i_mode)) {
++		au_fset_ren(a->flags, ISDIR);
++		if (unlikely(a->dst_inode && !S_ISDIR(a->dst_inode->i_mode)))
++			goto out_free;
++		aufs_read_and_write_lock2(a->dst_dentry, a->src_dentry,
++					  AuLock_DIR | AuLock_FLUSH);
++	} else
++		aufs_read_and_write_lock2(a->dst_dentry, a->src_dentry,
++					  AuLock_FLUSH);
++
++	au_fset_ren(a->flags, ISSAMEDIR); /* temporary */
++	di_write_lock_parent(a->dst_parent);
++
++	/* which branch we process */
++	err = au_ren_wbr(a);
++	if (unlikely(err < 0))
++		goto out_unlock;
++	a->br = au_sbr(a->dst_dentry->d_sb, a->btgt);
++	a->h_path.mnt = a->br->br_mnt;
++
++	/* are they available to be renamed */
++	err = au_ren_may_dir(a);
++	if (unlikely(err))
++		goto out_unlock;
++
++	/* prepare the writable parent dir on the same branch */
++	if (a->dst_bstart == a->btgt) {
++		au_fset_ren(a->flags, WHDST);
++	} else {
++		err = au_cpup_dirs(a->dst_dentry, a->btgt);
++		if (unlikely(err))
++			goto out_children;
++	}
++
++	if (a->src_dir != a->dst_dir) {
++		/*
++		 * this temporary unlock is safe,
++		 * because both dir->i_mutex are locked.
++		 */
++		di_write_unlock(a->dst_parent);
++		di_write_lock_parent(a->src_parent);
++		err = au_wr_dir_need_wh(a->src_dentry,
++					au_ftest_ren(a->flags, ISDIR),
++					&a->btgt);
++		di_write_unlock(a->src_parent);
++		di_write_lock2_parent(a->src_parent, a->dst_parent, /*isdir*/1);
++		au_fclr_ren(a->flags, ISSAMEDIR);
++	} else
++		err = au_wr_dir_need_wh(a->src_dentry,
++					au_ftest_ren(a->flags, ISDIR),
++					&a->btgt);
++	if (unlikely(err < 0))
++		goto out_children;
++	if (err)
++		au_fset_ren(a->flags, WHSRC);
++
++	/* lock them all */
++	err = au_ren_lock(a);
++	if (unlikely(err))
++		goto out_children;
++
++	if (!au_opt_test(au_mntflags(a->dst_dir->i_sb), UDBA_NONE)) {
++		err = au_may_ren(a);
++		if (unlikely(err))
++			goto out_hdir;
++	}
++
++	/* store timestamps to be revertible */
++	au_ren_dt(a);
++
++	/* here we go */
++	err = do_rename(a);
++	if (unlikely(err))
++		goto out_dt;
++
++	/* update dir attributes */
++	au_ren_refresh_dir(a);
++
++	/* dput/iput all lower dentries */
++	au_ren_refresh(a);
++
++	goto out_hdir; /* success */
++
++ out_dt:
++	au_ren_rev_dt(err, a);
++ out_hdir:
++	au_ren_unlock(a);
++ out_children:
++	au_nhash_fin(&a->whlist);
++ out_unlock:
++	if (unlikely(err && au_ftest_ren(a->flags, ISDIR))) {
++		au_update_dbstart(a->dst_dentry);
++		d_drop(a->dst_dentry);
++	}
++	if (!err) {
++		d_move(a->src_dentry, a->dst_dentry);
++		if (a->dst_inode
++		    && (a->dst_inode->i_nlink <= 1
++			|| au_ftest_ren(a->flags, ISDIR)))
++			a->dst_inode->i_flags |= S_DEAD;
++	}
++	if (au_ftest_ren(a->flags, ISSAMEDIR))
++		di_write_unlock(a->dst_parent);
++	else
++		di_write_unlock2(a->src_parent, a->dst_parent);
++	aufs_read_and_write_unlock2(a->dst_dentry, a->src_dentry);
++ out_free:
++	iput(a->dst_inode);
++	kfree(a);
++ out:
++	return err;
++}
+diff -uNr test/fs/aufs/iinfo.c aufs2-standalone/fs/aufs/iinfo.c
+--- test/fs/aufs/iinfo.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/iinfo.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,257 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * inode private data
++ */
++
++#include "aufs.h"
++
++struct inode *au_h_iptr(struct inode *inode, aufs_bindex_t bindex)
++{
++	struct inode *h_inode;
++
++	h_inode = au_ii(inode)->ii_hinode[0 + bindex].hi_inode;
++	AuDebugOn(h_inode && atomic_read(&h_inode->i_count) <= 0);
++	return h_inode;
++}
++
++/* todo: hard/soft set? */
++void au_set_ibstart(struct inode *inode, aufs_bindex_t bindex)
++{
++	struct au_iinfo *iinfo = au_ii(inode);
++	struct inode *h_inode;
++
++	iinfo->ii_bstart = bindex;
++	h_inode = iinfo->ii_hinode[bindex + 0].hi_inode;
++	if (h_inode)
++		au_cpup_igen(inode, h_inode);
++}
++
++void au_hiput(struct au_hinode *hinode)
++{
++	au_hin_free(hinode);
++	dput(hinode->hi_whdentry);
++	iput(hinode->hi_inode);
++}
++
++unsigned int au_hi_flags(struct inode *inode, int isdir)
++{
++	unsigned int flags;
++	const unsigned int mnt_flags = au_mntflags(inode->i_sb);
++
++	flags = 0;
++	if (au_opt_test(mnt_flags, XINO))
++		au_fset_hi(flags, XINO);
++	if (isdir && au_opt_test(mnt_flags, UDBA_HINOTIFY))
++		au_fset_hi(flags, HINOTIFY);
++	return flags;
++}
++
++void au_set_h_iptr(struct inode *inode, aufs_bindex_t bindex,
++		   struct inode *h_inode, unsigned int flags)
++{
++	struct au_hinode *hinode;
++	struct inode *hi;
++	struct au_iinfo *iinfo = au_ii(inode);
++
++	hinode = iinfo->ii_hinode + bindex;
++	hi = hinode->hi_inode;
++	AuDebugOn(h_inode && atomic_read(&h_inode->i_count) <= 0);
++	AuDebugOn(h_inode && hi);
++
++	if (hi)
++		au_hiput(hinode);
++	hinode->hi_inode = h_inode;
++	if (h_inode) {
++		int err;
++		struct super_block *sb = inode->i_sb;
++		struct au_branch *br;
++
++		if (bindex == iinfo->ii_bstart)
++			au_cpup_igen(inode, h_inode);
++		br = au_sbr(sb, bindex);
++		hinode->hi_id = br->br_id;
++		if (au_ftest_hi(flags, XINO)) {
++			err = au_xino_write(sb, bindex, h_inode->i_ino,
++					    inode->i_ino);
++			if (unlikely(err))
++				AuIOErr1("failed au_xino_write() %d\n", err);
++		}
++
++		if (au_ftest_hi(flags, HINOTIFY)
++		    && au_br_hinotifyable(br->br_perm)) {
++			err = au_hin_alloc(hinode, inode, h_inode);
++			if (unlikely(err))
++				AuIOErr1("au_hin_alloc() %d\n", err);
++		}
++	}
++}
++
++void au_set_hi_wh(struct inode *inode, aufs_bindex_t bindex,
++		  struct dentry *h_wh)
++{
++	struct au_hinode *hinode;
++
++	hinode = au_ii(inode)->ii_hinode + bindex;
++	AuDebugOn(hinode->hi_whdentry);
++	hinode->hi_whdentry = h_wh;
++}
++
++void au_update_iigen(struct inode *inode)
++{
++	atomic_set(&au_ii(inode)->ii_generation, au_sigen(inode->i_sb));
++	/* smp_mb(); */ /* atomic_set */
++}
++
++/* it may be called at remount time, too */
++void au_update_brange(struct inode *inode, int do_put_zero)
++{
++	struct au_iinfo *iinfo;
++
++	iinfo = au_ii(inode);
++	if (!iinfo || iinfo->ii_bstart < 0)
++		return;
++
++	if (do_put_zero) {
++		aufs_bindex_t bindex;
++
++		for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend;
++		     bindex++) {
++			struct inode *h_i;
++
++			h_i = iinfo->ii_hinode[0 + bindex].hi_inode;
++			if (h_i && !h_i->i_nlink)
++				au_set_h_iptr(inode, bindex, NULL, 0);
++		}
++	}
++
++	iinfo->ii_bstart = -1;
++	while (++iinfo->ii_bstart <= iinfo->ii_bend)
++		if (iinfo->ii_hinode[0 + iinfo->ii_bstart].hi_inode)
++			break;
++	if (iinfo->ii_bstart > iinfo->ii_bend) {
++		iinfo->ii_bstart = -1;
++		iinfo->ii_bend = -1;
++		return;
++	}
++
++	iinfo->ii_bend++;
++	while (0 <= --iinfo->ii_bend)
++		if (iinfo->ii_hinode[0 + iinfo->ii_bend].hi_inode)
++			break;
++	AuDebugOn(iinfo->ii_bstart > iinfo->ii_bend || iinfo->ii_bend < 0);
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_iinfo_init(struct inode *inode)
++{
++	struct au_iinfo *iinfo;
++	struct super_block *sb;
++	int nbr, i;
++
++	sb = inode->i_sb;
++	iinfo = &(container_of(inode, struct au_icntnr, vfs_inode)->iinfo);
++	nbr = au_sbend(sb) + 1;
++	if (unlikely(nbr <= 0))
++		nbr = 1;
++	iinfo->ii_hinode = kcalloc(nbr, sizeof(*iinfo->ii_hinode), GFP_NOFS);
++	if (iinfo->ii_hinode) {
++		for (i = 0; i < nbr; i++)
++			iinfo->ii_hinode[i].hi_id = -1;
++
++		atomic_set(&iinfo->ii_generation, au_sigen(sb));
++		/* smp_mb(); */ /* atomic_set */
++		init_rwsem(&iinfo->ii_rwsem);
++		iinfo->ii_bstart = -1;
++		iinfo->ii_bend = -1;
++		iinfo->ii_vdir = NULL;
++		return 0;
++	}
++	return -ENOMEM;
++}
++
++int au_ii_realloc(struct au_iinfo *iinfo, int nbr)
++{
++	int err, sz;
++	struct au_hinode *hip;
++
++	err = -ENOMEM;
++	sz = sizeof(*hip) * (iinfo->ii_bend + 1);
++	if (!sz)
++		sz = sizeof(*hip);
++	hip = au_kzrealloc(iinfo->ii_hinode, sz, sizeof(*hip) * nbr, GFP_NOFS);
++	if (hip) {
++		iinfo->ii_hinode = hip;
++		err = 0;
++	}
++
++	return err;
++}
++
++static int au_iinfo_write0(struct super_block *sb, struct au_hinode *hinode,
++			   ino_t ino)
++{
++	int err;
++	aufs_bindex_t bindex;
++	unsigned char locked;
++
++	err = 0;
++	locked = !!si_noflush_read_trylock(sb);
++	bindex = au_br_index(sb, hinode->hi_id);
++	if (bindex >= 0)
++		err = au_xino_write0(sb, bindex, hinode->hi_inode->i_ino, ino);
++	/* error action? */
++	if (locked)
++		si_read_unlock(sb);
++	return err;
++}
++
++void au_iinfo_fin(struct inode *inode)
++{
++	ino_t ino;
++	aufs_bindex_t bend;
++	unsigned char unlinked;
++	struct au_iinfo *iinfo;
++	struct au_hinode *hi;
++	struct super_block *sb;
++
++	iinfo = au_ii(inode);
++	/* bad_inode case */
++	if (!iinfo)
++		return;
++
++	if (iinfo->ii_vdir)
++		au_vdir_free(iinfo->ii_vdir);
++
++	if (iinfo->ii_bstart >= 0) {
++		sb = inode->i_sb;
++		unlinked = !inode->i_nlink;
++		ino = 0;
++		if (unlinked)
++			ino = inode->i_ino;
++		hi = iinfo->ii_hinode + iinfo->ii_bstart;
++		bend = iinfo->ii_bend;
++		while (iinfo->ii_bstart++ <= bend) {
++			if (hi->hi_inode) {
++				if (unlinked || !hi->hi_inode->i_nlink) {
++					au_iinfo_write0(sb, hi, ino);
++					/* ignore this error */
++					ino = 0;
++				}
++				au_hiput(hi);
++			}
++			hi++;
++		}
++	}
++
++	kfree(iinfo->ii_hinode);
++	au_rwsem_destroy(&iinfo->ii_rwsem);
++}
+diff -uNr test/fs/aufs/inode.c aufs2-standalone/fs/aufs/inode.c
+--- test/fs/aufs/inode.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/inode.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,356 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * inode functions
++ */
++
++#include "aufs.h"
++
++static void au_refresh_hinode_attr(struct inode *inode, int do_version)
++{
++	au_cpup_attr_all(inode, /*force*/0);
++	au_update_iigen(inode);
++	if (do_version)
++		inode->i_version++;
++}
++
++int au_refresh_hinode_self(struct inode *inode, int do_attr)
++{
++	int err;
++	aufs_bindex_t bindex, new_bindex;
++	unsigned char update;
++	struct inode *first;
++	struct au_hinode *p, *q, tmp;
++	struct super_block *sb;
++	struct au_iinfo *iinfo;
++
++	update = 0;
++	sb = inode->i_sb;
++	iinfo = au_ii(inode);
++	err = au_ii_realloc(iinfo, au_sbend(sb) + 1);
++	if (unlikely(err))
++		goto out;
++
++	p = iinfo->ii_hinode + iinfo->ii_bstart;
++	first = p->hi_inode;
++	err = 0;
++	for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend;
++	     bindex++, p++) {
++		if (!p->hi_inode)
++			continue;
++
++		new_bindex = au_br_index(sb, p->hi_id);
++		if (new_bindex == bindex)
++			continue;
++
++		if (new_bindex < 0) {
++			update++;
++			au_hiput(p);
++			p->hi_inode = NULL;
++			continue;
++		}
++
++		if (new_bindex < iinfo->ii_bstart)
++			iinfo->ii_bstart = new_bindex;
++		if (iinfo->ii_bend < new_bindex)
++			iinfo->ii_bend = new_bindex;
++		/* swap two lower inode, and loop again */
++		q = iinfo->ii_hinode + new_bindex;
++		tmp = *q;
++		*q = *p;
++		*p = tmp;
++		if (tmp.hi_inode) {
++			bindex--;
++			p--;
++		}
++	}
++	au_update_brange(inode, /*do_put_zero*/0);
++	if (do_attr)
++		au_refresh_hinode_attr(inode, update && S_ISDIR(inode->i_mode));
++
++ out:
++	return err;
++}
++
++int au_refresh_hinode(struct inode *inode, struct dentry *dentry)
++{
++	int err, update;
++	unsigned int flags;
++	aufs_bindex_t bindex, bend;
++	unsigned char isdir;
++	struct inode *first;
++	struct au_hinode *p;
++	struct au_iinfo *iinfo;
++
++	err = au_refresh_hinode_self(inode, /*do_attr*/0);
++	if (unlikely(err))
++		goto out;
++
++	update = 0;
++	iinfo = au_ii(inode);
++	p = iinfo->ii_hinode + iinfo->ii_bstart;
++	first = p->hi_inode;
++	isdir = S_ISDIR(inode->i_mode);
++	flags = au_hi_flags(inode, isdir);
++	bend = au_dbend(dentry);
++	for (bindex = au_dbstart(dentry); bindex <= bend; bindex++) {
++		struct inode *h_i;
++		struct dentry *h_d;
++
++		h_d = au_h_dptr(dentry, bindex);
++		if (!h_d || !h_d->d_inode)
++			continue;
++
++		if (iinfo->ii_bstart <= bindex && bindex <= iinfo->ii_bend) {
++			h_i = au_h_iptr(inode, bindex);
++			if (h_i) {
++				if (h_i == h_d->d_inode)
++					continue;
++				err = -EIO;
++				break;
++			}
++		}
++		if (bindex < iinfo->ii_bstart)
++			iinfo->ii_bstart = bindex;
++		if (iinfo->ii_bend < bindex)
++			iinfo->ii_bend = bindex;
++		au_set_h_iptr(inode, bindex, au_igrab(h_d->d_inode), flags);
++		update = 1;
++	}
++	au_update_brange(inode, /*do_put_zero*/0);
++
++	if (unlikely(err))
++		goto out;
++
++	au_refresh_hinode_attr(inode, update && isdir);
++
++ out:
++	return err;
++}
++
++static int set_inode(struct inode *inode, struct dentry *dentry)
++{
++	int err;
++	unsigned int flags;
++	umode_t mode;
++	aufs_bindex_t bindex, bstart, btail;
++	unsigned char isdir;
++	struct dentry *h_dentry;
++	struct inode *h_inode;
++	struct au_iinfo *iinfo;
++
++	err = 0;
++	isdir = 0;
++	bstart = au_dbstart(dentry);
++	h_inode = au_h_dptr(dentry, bstart)->d_inode;
++	mode = h_inode->i_mode;
++	switch (mode & S_IFMT) {
++	case S_IFREG:
++		btail = au_dbtail(dentry);
++		inode->i_op = &aufs_iop;
++		inode->i_fop = &aufs_file_fop;
++		inode->i_mapping->a_ops = &aufs_aop;
++		break;
++	case S_IFDIR:
++		isdir = 1;
++		btail = au_dbtaildir(dentry);
++		inode->i_op = &aufs_dir_iop;
++		inode->i_fop = &aufs_dir_fop;
++		break;
++	case S_IFLNK:
++		btail = au_dbtail(dentry);
++		inode->i_op = &aufs_symlink_iop;
++		break;
++	case S_IFBLK:
++	case S_IFCHR:
++	case S_IFIFO:
++	case S_IFSOCK:
++		btail = au_dbtail(dentry);
++		inode->i_op = &aufs_iop;
++		init_special_inode(inode, mode, h_inode->i_rdev);
++		break;
++	default:
++		AuIOErr("Unknown file type 0%o\n", mode);
++		err = -EIO;
++		goto out;
++	}
++
++	flags = au_hi_flags(inode, isdir);
++	iinfo = au_ii(inode);
++	iinfo->ii_bstart = bstart;
++	iinfo->ii_bend = btail;
++	for (bindex = bstart; bindex <= btail; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (h_dentry)
++			au_set_h_iptr(inode, bindex,
++				      au_igrab(h_dentry->d_inode), flags);
++	}
++	au_cpup_attr_all(inode, /*force*/1);
++
++ out:
++	return err;
++}
++
++/* successful returns with iinfo write_locked */
++static int reval_inode(struct inode *inode, struct dentry *dentry, int *matched)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	struct inode *h_inode, *h_dinode;
++
++	*matched = 0;
++
++	/*
++	 * before this function, if aufs got any iinfo lock, it must be only
++	 * one, the parent dir.
++	 * it can happen by UDBA and the obsoleted inode number.
++	 */
++	err = -EIO;
++	if (unlikely(inode->i_ino == parent_ino(dentry)))
++		goto out;
++
++	ii_write_lock_new_child(inode);
++	if (unlikely(IS_DEADDIR(inode)))
++		goto out_unlock;
++
++	err = 0;
++	h_dinode = au_h_dptr(dentry, au_dbstart(dentry))->d_inode;
++	bend = au_ibend(inode);
++	for (bindex = au_ibstart(inode); bindex <= bend; bindex++) {
++		h_inode = au_h_iptr(inode, bindex);
++		if (h_inode && h_inode == h_dinode) {
++			*matched = 1;
++			err = 0;
++			if (au_iigen(inode) != au_digen(dentry))
++				err = au_refresh_hinode(inode, dentry);
++			break;
++		}
++	}
++
++ out_unlock:
++	if (unlikely(err))
++		ii_write_unlock(inode);
++ out:
++	return err;
++}
++
++/* successful returns with iinfo write_locked */
++/* todo: return with unlocked? */
++struct inode *au_new_inode(struct dentry *dentry, int must_new)
++{
++	struct inode *inode;
++	struct dentry *h_dentry;
++	struct super_block *sb;
++	ino_t h_ino, ino;
++	int err, match;
++	aufs_bindex_t bstart;
++
++	sb = dentry->d_sb;
++	bstart = au_dbstart(dentry);
++	h_dentry = au_h_dptr(dentry, bstart);
++	h_ino = h_dentry->d_inode->i_ino;
++	err = au_xino_read(sb, bstart, h_ino, &ino);
++	inode = ERR_PTR(err);
++	if (unlikely(err))
++		goto out;
++ new_ino:
++	if (!ino) {
++		ino = au_xino_new_ino(sb);
++		if (unlikely(!ino)) {
++			inode = ERR_PTR(-EIO);
++			goto out;
++		}
++	}
++
++	AuDbg("i%lu\n", (unsigned long)ino);
++	inode = au_iget_locked(sb, ino);
++	err = PTR_ERR(inode);
++	if (IS_ERR(inode))
++		goto out;
++
++	AuDbg("%lx, new %d\n", inode->i_state, !!(inode->i_state & I_NEW));
++	if (inode->i_state & I_NEW) {
++		ii_write_lock_new_child(inode);
++		err = set_inode(inode, dentry);
++		unlock_new_inode(inode);
++		if (!err)
++			goto out; /* success */
++
++		iget_failed(inode);
++		ii_write_unlock(inode);
++		goto out_iput;
++	} else if (!must_new) {
++		err = reval_inode(inode, dentry, &match);
++		if (!err)
++			goto out; /* success */
++		else if (match)
++			goto out_iput;
++	}
++
++	if (unlikely(au_test_fs_unique_ino(h_dentry->d_inode)))
++		AuWarn1("Un-notified UDBA or repeatedly renamed dir,"
++			" b%d, %s, %.*s, hi%lu, i%lu.\n",
++			bstart, au_sbtype(h_dentry->d_sb), AuDLNPair(dentry),
++			(unsigned long)h_ino, (unsigned long)ino);
++	ino = 0;
++	err = au_xino_write0(sb, bstart, h_ino, 0);
++	if (!err) {
++		iput(inode);
++		goto new_ino;
++	}
++
++ out_iput:
++	iput(inode);
++	inode = ERR_PTR(err);
++ out:
++	return inode;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,
++	       struct inode *inode)
++{
++	int err;
++
++	err = au_br_rdonly(au_sbr(sb, bindex));
++
++	/* pseudo-link after flushed may happen out of bounds */
++	if (!err
++	    && inode
++	    && au_ibstart(inode) <= bindex
++	    && bindex <= au_ibend(inode)) {
++		/*
++		 * permission check is unnecessary since vfsub routine
++		 * will be called later
++		 */
++		struct inode *hi = au_h_iptr(inode, bindex);
++		if (hi)
++			err = IS_IMMUTABLE(hi) ? -EROFS : 0;
++	}
++
++	return err;
++}
++
++int au_test_h_perm(struct inode *h_inode, int mask)
++{
++	if (!current->fsuid)
++		return 0;
++	return inode_permission(h_inode, mask);
++}
++
++int au_test_h_perm_sio(struct inode *h_inode, int mask)
++{
++	if (au_test_nfs(h_inode->i_sb)
++	    && (mask & MAY_WRITE)
++	    && S_ISDIR(h_inode->i_mode))
++		mask |= MAY_READ; /* force permission check */
++	return au_test_h_perm(h_inode, mask);
++}
+diff -uNr test/fs/aufs/inode.h aufs2-standalone/fs/aufs/inode.h
+--- test/fs/aufs/inode.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/inode.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,471 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * inode operations
++ */
++
++#ifndef __AUFS_INODE_H__
++#define __AUFS_INODE_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/inotify.h>
++#include <linux/namei.h>
++#include <linux/aufs_type.h>
++#include "rwsem.h"
++
++struct au_hinotify {
++#ifdef CONFIG_AUFS_HINOTIFY
++	struct inotify_watch	hin_watch;
++	struct inode		*hin_aufs_inode;	/* no get/put */
++#endif
++};
++
++struct au_hinode {
++	struct inode		*hi_inode;
++	aufs_bindex_t		hi_id;
++#ifdef CONFIG_AUFS_HINOTIFY
++	struct au_hinotify	*hi_notify;
++#endif
++
++	/* reference to the copied-up whiteout with get/put */
++	struct dentry		*hi_whdentry;
++};
++
++struct au_vdir;
++struct au_iinfo {
++	atomic_t		ii_generation;
++	struct super_block	*ii_hsb1;	/* no get/put */
++
++	struct rw_semaphore	ii_rwsem;
++	aufs_bindex_t		ii_bstart, ii_bend;
++	__u32			ii_higen;
++	struct au_hinode	*ii_hinode;
++	struct au_vdir		*ii_vdir;
++};
++
++struct au_icntnr {
++	struct au_iinfo iinfo;
++	struct inode vfs_inode;
++};
++
++/* au_pin flags */
++#define AuPin_DI_LOCKED		1
++#define AuPin_MNT_WRITE		(1 << 1)
++#define au_ftest_pin(flags, name)	((flags) & AuPin_##name)
++#define au_fset_pin(flags, name)	{ (flags) |= AuPin_##name; }
++#define au_fclr_pin(flags, name)	{ (flags) &= ~AuPin_##name; }
++
++struct au_pin {
++	/* input */
++	struct dentry *dentry;
++	unsigned int udba;
++	unsigned char lsc_di, lsc_hi, flags;
++	aufs_bindex_t bindex;
++
++	/* output */
++	struct dentry *parent;
++	struct au_hinode *hdir;
++	struct vfsmount *h_mnt;
++};
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct au_iinfo *au_ii(struct inode *inode)
++{
++	struct au_iinfo *iinfo;
++
++	iinfo = &(container_of(inode, struct au_icntnr, vfs_inode)->iinfo);
++	if (iinfo->ii_hinode)
++		return iinfo;
++	return NULL; /* debugging bad_inode case */
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* inode.c */
++int au_refresh_hinode_self(struct inode *inode, int do_attr);
++int au_refresh_hinode(struct inode *inode, struct dentry *dentry);
++struct inode *au_new_inode(struct dentry *dentry, int must_new);
++int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,
++	       struct inode *inode);
++int au_test_h_perm(struct inode *h_inode, int mask);
++int au_test_h_perm_sio(struct inode *h_inode, int mask);
++
++/* i_op.c */
++extern struct inode_operations aufs_iop, aufs_symlink_iop, aufs_dir_iop;
++
++/* au_wr_dir flags */
++#define AuWrDir_ADD_ENTRY	1
++#define AuWrDir_ISDIR		(1 << 1)
++#define au_ftest_wrdir(flags, name)	((flags) & AuWrDir_##name)
++#define au_fset_wrdir(flags, name)	{ (flags) |= AuWrDir_##name; }
++#define au_fclr_wrdir(flags, name)	{ (flags) &= ~AuWrDir_##name; }
++
++struct au_wr_dir_args {
++	aufs_bindex_t force_btgt;
++	unsigned char flags;
++};
++int au_wr_dir(struct dentry *dentry, struct dentry *src_dentry,
++	      struct au_wr_dir_args *args);
++
++struct dentry *au_pinned_h_parent(struct au_pin *pin);
++void au_pin_init(struct au_pin *pin, struct dentry *dentry,
++		 aufs_bindex_t bindex, int lsc_di, int lsc_hi,
++		 unsigned int udba, unsigned char flags);
++int au_pin(struct au_pin *pin, struct dentry *dentry, aufs_bindex_t bindex,
++	   unsigned int udba, unsigned char flags) __must_check;
++int au_do_pin(struct au_pin *pin) __must_check;
++void au_unpin(struct au_pin *pin);
++
++/* i_op_add.c */
++int au_may_add(struct dentry *dentry, aufs_bindex_t bindex,
++	       struct dentry *h_parent, int isdir);
++int aufs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev);
++int aufs_symlink(struct inode *dir, struct dentry *dentry, const char *symname);
++int aufs_create(struct inode *dir, struct dentry *dentry, int mode,
++		struct nameidata *nd);
++int aufs_link(struct dentry *src_dentry, struct inode *dir,
++	      struct dentry *dentry);
++int aufs_mkdir(struct inode *dir, struct dentry *dentry, int mode);
++
++/* i_op_del.c */
++int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup);
++int au_may_del(struct dentry *dentry, aufs_bindex_t bindex,
++	       struct dentry *h_parent, int isdir);
++int aufs_unlink(struct inode *dir, struct dentry *dentry);
++int aufs_rmdir(struct inode *dir, struct dentry *dentry);
++
++/* i_op_ren.c */
++int au_wbr(struct dentry *dentry, aufs_bindex_t btgt);
++int aufs_rename(struct inode *src_dir, struct dentry *src_dentry,
++		struct inode *dir, struct dentry *dentry);
++
++/* iinfo.c */
++struct inode *au_h_iptr(struct inode *inode, aufs_bindex_t bindex);
++void au_hiput(struct au_hinode *hinode);
++void au_set_ibstart(struct inode *inode, aufs_bindex_t bindex);
++void au_set_hi_wh(struct inode *inode, aufs_bindex_t bindex,
++		  struct dentry *h_wh);
++unsigned int au_hi_flags(struct inode *inode, int isdir);
++
++/* hinode flags */
++#define AuHi_XINO	1
++#define AuHi_HINOTIFY	(1 << 1)
++#define au_ftest_hi(flags, name)	((flags) & AuHi_##name)
++#define au_fset_hi(flags, name)		{ (flags) |= AuHi_##name; }
++#define au_fclr_hi(flags, name)		{ (flags) &= ~AuHi_##name; }
++
++#ifndef CONFIG_AUFS_HINOTIFY
++#undef AuHi_HINOTIFY
++#define AuHi_HINOTIFY	0
++#endif
++
++void au_set_h_iptr(struct inode *inode, aufs_bindex_t bindex,
++		   struct inode *h_inode, unsigned int flags);
++
++void au_update_iigen(struct inode *inode);
++void au_update_brange(struct inode *inode, int do_put_zero);
++
++int au_iinfo_init(struct inode *inode);
++void au_iinfo_fin(struct inode *inode);
++int au_ii_realloc(struct au_iinfo *iinfo, int nbr);
++
++/* plink.c */
++void au_plink_block_maintain(struct super_block *sb);
++#ifdef CONFIG_AUFS_DEBUG
++void au_plink_list(struct super_block *sb);
++#else
++static inline void au_plink_list(struct super_block *sb)
++{
++	/* nothing */
++}
++#endif
++int au_plink_test(struct inode *inode);
++struct dentry *au_plink_lkup(struct inode *inode, aufs_bindex_t bindex);
++void au_plink_append(struct inode *inode, aufs_bindex_t bindex,
++		     struct dentry *h_dentry);
++void au_plink_put(struct super_block *sb);
++void au_plink_half_refresh(struct super_block *sb, aufs_bindex_t br_id);
++
++/* ---------------------------------------------------------------------- */
++
++/* lock subclass for iinfo */
++enum {
++	AuLsc_II_CHILD,		/* child first */
++	AuLsc_II_CHILD2,	/* rename(2), link(2), and cpup at hinotify */
++	AuLsc_II_CHILD3,	/* copyup dirs */
++	AuLsc_II_PARENT,	/* see AuLsc_I_PARENT in vfsub.h */
++	AuLsc_II_PARENT2,
++	AuLsc_II_PARENT3,	/* copyup dirs */
++	AuLsc_II_NEW_CHILD
++};
++
++/*
++ * ii_read_lock_child, ii_write_lock_child,
++ * ii_read_lock_child2, ii_write_lock_child2,
++ * ii_read_lock_child3, ii_write_lock_child3,
++ * ii_read_lock_parent, ii_write_lock_parent,
++ * ii_read_lock_parent2, ii_write_lock_parent2,
++ * ii_read_lock_parent3, ii_write_lock_parent3,
++ * ii_read_lock_new_child, ii_write_lock_new_child,
++ */
++#define AuReadLockFunc(name, lsc) \
++static inline void ii_read_lock_##name(struct inode *i) \
++{ \
++	down_read_nested(&au_ii(i)->ii_rwsem, AuLsc_II_##lsc); \
++}
++
++#define AuWriteLockFunc(name, lsc) \
++static inline void ii_write_lock_##name(struct inode *i) \
++{ \
++	down_write_nested(&au_ii(i)->ii_rwsem, AuLsc_II_##lsc); \
++}
++
++#define AuRWLockFuncs(name, lsc) \
++	AuReadLockFunc(name, lsc) \
++	AuWriteLockFunc(name, lsc)
++
++AuRWLockFuncs(child, CHILD);
++AuRWLockFuncs(child2, CHILD2);
++AuRWLockFuncs(child3, CHILD3);
++AuRWLockFuncs(parent, PARENT);
++AuRWLockFuncs(parent2, PARENT2);
++AuRWLockFuncs(parent3, PARENT3);
++AuRWLockFuncs(new_child, NEW_CHILD);
++
++#undef AuReadLockFunc
++#undef AuWriteLockFunc
++#undef AuRWLockFuncs
++
++/*
++ * ii_read_unlock, ii_write_unlock, ii_downgrade_lock
++ */
++AuSimpleUnlockRwsemFuncs(ii, struct inode *i, &au_ii(i)->ii_rwsem);
++
++#define IiMustNoWaiters(i)	AuRwMustNoWaiters(&au_ii(i)->ii_rwsem)
++
++/* ---------------------------------------------------------------------- */
++
++static inline unsigned int au_iigen(struct inode *inode)
++{
++	return atomic_read(&au_ii(inode)->ii_generation);
++}
++
++/* tiny test for inode number */
++/* tmpfs generation is too rough */
++static inline int au_test_higen(struct inode *inode, struct inode *h_inode)
++{
++	struct au_iinfo *iinfo;
++
++	iinfo = au_ii(inode);
++	return !(iinfo->ii_hsb1 == h_inode->i_sb
++		 && iinfo->ii_higen == h_inode->i_generation);
++}
++
++static inline struct inode *au_igrab(struct inode *inode)
++{
++	if (inode) {
++		AuDebugOn(!atomic_read(&inode->i_count));
++		atomic_inc(&inode->i_count);
++	}
++	return inode;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static inline aufs_bindex_t au_ii_br_id(struct inode *inode,
++					aufs_bindex_t bindex)
++{
++	return au_ii(inode)->ii_hinode[0 + bindex].hi_id;
++}
++
++static inline aufs_bindex_t au_ibstart(struct inode *inode)
++{
++	return au_ii(inode)->ii_bstart;
++}
++
++static inline aufs_bindex_t au_ibend(struct inode *inode)
++{
++	return au_ii(inode)->ii_bend;
++}
++
++static inline struct au_vdir *au_ivdir(struct inode *inode)
++{
++	return au_ii(inode)->ii_vdir;
++}
++
++static inline struct dentry *au_hi_wh(struct inode *inode, aufs_bindex_t bindex)
++{
++	return au_ii(inode)->ii_hinode[0 + bindex].hi_whdentry;
++}
++
++static inline void au_set_ibend(struct inode *inode, aufs_bindex_t bindex)
++{
++	au_ii(inode)->ii_bend = bindex;
++}
++
++static inline void au_set_ivdir(struct inode *inode, struct au_vdir *vdir)
++{
++	au_ii(inode)->ii_vdir = vdir;
++}
++
++static inline struct au_hinode *au_hi(struct inode *inode, aufs_bindex_t bindex)
++{
++	return au_ii(inode)->ii_hinode + bindex;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct dentry *au_pinned_parent(struct au_pin *pin)
++{
++	if (pin)
++		return pin->parent;
++	return NULL;
++}
++
++static inline struct inode *au_pinned_h_dir(struct au_pin *pin)
++{
++	if (pin && pin->hdir)
++		return pin->hdir->hi_inode;
++	return NULL;
++}
++
++static inline struct au_hinode *au_pinned_hdir(struct au_pin *pin)
++{
++	if (pin)
++		return pin->hdir;
++	return NULL;
++}
++
++static inline void au_pin_set_dentry(struct au_pin *pin, struct dentry *dentry)
++{
++	if (pin)
++		pin->dentry = dentry;
++}
++
++static inline void au_pin_set_parent_lflag(struct au_pin *pin,
++					   unsigned char lflag)
++{
++	if (pin) {
++		/* dirty macros require brackets */
++		if (lflag) {
++			au_fset_pin(pin->flags, DI_LOCKED);
++		} else {
++			au_fclr_pin(pin->flags, DI_LOCKED);
++		}
++	}
++}
++
++static inline void au_pin_set_parent(struct au_pin *pin, struct dentry *parent)
++{
++	if (pin) {
++		dput(pin->parent);
++		pin->parent = dget(parent);
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_HINOTIFY
++/* hinotify.c */
++int au_hin_alloc(struct au_hinode *hinode, struct inode *inode,
++		 struct inode *h_inode);
++void au_hin_free(struct au_hinode *hinode);
++void au_hin_ctl(struct au_hinode *hinode, int do_set);
++void au_reset_hinotify(struct inode *inode, unsigned int flags);
++
++int __init au_hinotify_init(void);
++void au_hinotify_fin(void);
++
++static inline
++void au_hin_init(struct au_hinode *hinode, struct au_hinotify *val)
++{
++	hinode->hi_notify = val;
++}
++
++static inline void au_iigen_dec(struct inode *inode)
++{
++	atomic_dec(&au_ii(inode)->ii_generation);
++}
++
++#else
++static inline
++int au_hin_alloc(struct au_hinode *hinode __maybe_unused,
++		 struct inode *inode __maybe_unused,
++		 struct inode *h_inode __maybe_unused)
++{
++	return -EOPNOTSUPP;
++}
++
++static inline void au_hin_free(struct au_hinode *hinode __maybe_unused)
++{
++	/* nothing */
++}
++
++static inline void au_hin_ctl(struct au_hinode *hinode __maybe_unused,
++			      int do_set __maybe_unused)
++{
++	/* nothing */
++}
++
++static inline void au_reset_hinotify(struct inode *inode __maybe_unused,
++				     unsigned int flags __maybe_unused)
++{
++	/* nothing */
++}
++
++static inline int au_hinotify_init(void)
++{
++	return 0;
++}
++
++#define au_hinotify_fin()	do {} while (0)
++
++static inline
++void au_hin_init(struct au_hinode *hinode __maybe_unused,
++		 struct au_hinotify *val __maybe_unused)
++{
++	/* empty */
++}
++#endif /* CONFIG_AUFS_HINOTIFY */
++
++static inline void au_hin_suspend(struct au_hinode *hdir)
++{
++	au_hin_ctl(hdir, /*do_set*/0);
++}
++
++static inline void au_hin_resume(struct au_hinode *hdir)
++{
++	au_hin_ctl(hdir, /*do_set*/1);
++}
++
++static inline void au_hin_imtx_lock(struct au_hinode *hdir)
++{
++	mutex_lock(&hdir->hi_inode->i_mutex);
++	au_hin_suspend(hdir);
++}
++
++static inline void au_hin_imtx_lock_nested(struct au_hinode *hdir,
++					   unsigned int sc __maybe_unused)
++{
++	mutex_lock_nested(&hdir->hi_inode->i_mutex, sc);
++	au_hin_suspend(hdir);
++}
++
++static inline void au_hin_imtx_unlock(struct au_hinode *hdir)
++{
++	au_hin_resume(hdir);
++	mutex_unlock(&hdir->hi_inode->i_mutex);
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_INODE_H__ */
+diff -uNr test/fs/aufs/ioctl.c aufs2-standalone/fs/aufs/ioctl.c
+--- test/fs/aufs/ioctl.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/ioctl.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,54 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++#include <linux/uaccess.h>
++#include "aufs.h"
++
++long aufs_ioctl_dir(struct file *file, unsigned int cmd,
++		    unsigned long arg __maybe_unused)
++{
++	long err;
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++
++	err = -EACCES;
++	if (!capable(CAP_SYS_ADMIN))
++		goto out;
++
++	err = 0;
++	sb = file->f_dentry->d_sb;
++	sbinfo = au_sbi(sb);
++	switch (cmd) {
++	case AUFS_CTL_PLINK_MAINT:
++		/*
++		 * pseudo-link maintenance mode,
++		 * cleared by aufs_release_dir()
++		 */
++		si_write_lock(sb);
++		if (!au_ftest_si(sbinfo, MAINTAIN_PLINK)) {
++			au_fset_si(sbinfo, MAINTAIN_PLINK);
++			au_fi(file)->fi_maintain_plink = 1;
++		} else
++			err = -EBUSY;
++		si_write_unlock(sb);
++		break;
++	case AUFS_CTL_PLINK_CLEAN:
++		if (au_opt_test(sbinfo->si_mntflags, PLINK)) {
++			aufs_write_lock(sb->s_root);
++			au_plink_put(sb);
++			aufs_write_unlock(sb->s_root);
++		}
++		break;
++	default:
++		err = -EINVAL;
++	}
++
++ out:
++	return err;
++}
+diff -uNr test/fs/aufs/loop.c aufs2-standalone/fs/aufs/loop.c
+--- test/fs/aufs/loop.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/loop.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,46 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * support for loopback block device as a branch
++ */
++
++#include <linux/loop.h>
++#include "aufs.h"
++
++/*
++ * test if two lower dentries have overlapping branches.
++ */
++int au_test_loopback_overlap(struct super_block *sb, struct dentry *h_d1,
++			     struct dentry *h_d2)
++{
++	struct inode *h_inode;
++	struct loop_device *l;
++
++	h_inode = h_d1->d_inode;
++	if (MAJOR(h_inode->i_sb->s_dev) != LOOP_MAJOR)
++		return 0;
++
++	l = h_inode->i_sb->s_bdev->bd_disk->private_data;
++	h_d1 = l->lo_backing_file->f_dentry;
++	/* h_d1 can be local NFS. in this case aufs cannot detect the loop */
++	if (unlikely(h_d1->d_sb == sb))
++		return 1;
++	return !!au_test_subdir(h_d1, h_d2);
++}
++
++/* true if a kernel thread named 'loop[0-9].*' accesses a file */
++int au_test_loopback_kthread(void)
++{
++	const char c = current->comm[4];
++
++	return current->mm == NULL
++	       && '0' <= c && c <= '9'
++	       && strncmp(current->comm, "loop", 4) == 0;
++}
+diff -uNr test/fs/aufs/loop.h aufs2-standalone/fs/aufs/loop.h
+--- test/fs/aufs/loop.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/loop.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,41 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * support for loopback mount as a branch
++ */
++
++#ifndef __AUFS_LOOP_H__
++#define __AUFS_LOOP_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++
++#ifdef CONFIG_AUFS_BDEV_LOOP
++/* loop.c */
++int au_test_loopback_overlap(struct super_block *sb, struct dentry *h_d1,
++			     struct dentry *h_d2);
++int au_test_loopback_kthread(void);
++#else
++static inline
++int au_test_loopback_overlap(struct super_block *sb, struct dentry *h_d1,
++			     struct dentry *h_d2)
++{
++	return 0;
++}
++
++static inline int au_test_loopback_kthread(void)
++{
++	return 0;
++}
++#endif /* BLK_DEV_LOOP */
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_LOOP_H__ */
+diff -uNr test/fs/aufs/magic.mk aufs2-standalone/fs/aufs/magic.mk
+--- test/fs/aufs/magic.mk	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/magic.mk	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,52 @@
++
++# defined in ${srctree}/fs/fuse/inode.c
++# tristate
++ifdef CONFIG_FUSE_FS
++ccflags-y += -DFUSE_SUPER_MAGIC=0x65735546
++endif
++
++# defined in ${srctree}/fs/ocfs2/ocfs2_fs.h
++# tristate
++ifdef CONFIG_OCFS2_FS
++ccflags-y += -DOCFS2_SUPER_MAGIC=0x7461636f
++endif
++
++# defined in ${srctree}/fs/ocfs2/dlm/userdlm.h
++# tristate
++ifdef CONFIG_OCFS2_FS_O2CB
++ccflags-y += -DDLMFS_MAGIC=0x76a9f425
++endif
++
++# defined in ${srctree}/fs/ramfs/inode.c
++# always true
++ccflags-y += -DRAMFS_MAGIC=0x858458f6
++
++# defined in ${srctree}/fs/cifs/cifsfs.c
++# tristate
++ifdef CONFIG_CIFS_FS
++ccflags-y += -DCIFS_MAGIC_NUMBER=0xFF534D42
++endif
++
++# defined in ${srctree}/fs/xfs/xfs_sb.h
++# tristate
++ifdef CONFIG_XFS_FS
++ccflags-y += -DXFS_SB_MAGIC=0x58465342
++endif
++
++# defined in ${srctree}/fs/configfs/mount.c
++# tristate
++ifdef CONFIG_CONFIGFS_FS
++ccflags-y += -DCONFIGFS_MAGIC=0x62656570
++endif
++
++# defined in ${srctree}/fs/9p/v9fs.h
++# tristate
++ifdef CONFIG_9P_FS
++ccflags-y += -DV9FS_MAGIC=0x01021997
++endif
++
++# defined in ${srctree}/fs/ubifs/ubifs.h
++# tristate
++ifdef CONFIG_UBIFS_FS
++ccflags-y += -DUBIFS_SUPER_MAGIC=0x24051905
++endif
+diff -uNr test/fs/aufs/module.c aufs2-standalone/fs/aufs/module.c
+--- test/fs/aufs/module.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/module.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,164 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * module global variables and operations
++ */
++
++#include <linux/module.h>
++#include <linux/seq_file.h>
++#include "aufs.h"
++
++void *au_kzrealloc(void *p, unsigned int nused, unsigned int new_sz, gfp_t gfp)
++{
++	if (new_sz <= nused)
++		return p;
++
++	p = krealloc(p, new_sz, gfp);
++	if (p)
++		memset(p + nused, 0, new_sz - nused);
++	return p;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * aufs caches
++ */
++struct kmem_cache *au_cachep[AuCache_Last];
++static int __init au_cache_init(void)
++{
++	au_cachep[AuCache_DINFO] = AuCache(au_dinfo);
++	if (au_cachep[AuCache_DINFO])
++		au_cachep[AuCache_ICNTNR] = AuCache(au_icntnr);
++	if (au_cachep[AuCache_ICNTNR])
++		au_cachep[AuCache_FINFO] = AuCache(au_finfo);
++	if (au_cachep[AuCache_FINFO])
++		au_cachep[AuCache_VDIR] = AuCache(au_vdir);
++	if (au_cachep[AuCache_VDIR])
++		au_cachep[AuCache_DEHSTR] = AuCache(au_vdir_dehstr);
++	if (au_cachep[AuCache_DEHSTR])
++		return 0;
++
++	return -ENOMEM;
++}
++
++static void au_cache_fin(void)
++{
++	int i;
++	for (i = 0; i < AuCache_Last; i++)
++		if (au_cachep[i]) {
++			kmem_cache_destroy(au_cachep[i]);
++			au_cachep[i] = NULL;
++		}
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_dir_roflags;
++
++/*
++ * functions for module interface.
++ */
++MODULE_LICENSE("GPL");
++/* MODULE_LICENSE("GPL v2"); */
++MODULE_AUTHOR("Junjiro R. Okajima");
++MODULE_DESCRIPTION(AUFS_NAME
++	" -- Advanced multi layered unification filesystem");
++MODULE_VERSION(AUFS_VERSION);
++
++/* it should be 'byte', but param_set_byte() prints it by "%c" */
++short aufs_nwkq = AUFS_NWKQ_DEF;
++MODULE_PARM_DESC(nwkq, "the number of workqueue thread, " AUFS_WKQ_NAME);
++module_param_named(nwkq, aufs_nwkq, short, S_IRUGO);
++
++/* this module parameter has no meaning when SYSFS is disabled */
++int sysaufs_brs = 1;
++MODULE_PARM_DESC(brs, "use <sysfs>/fs/aufs/si_*/brN");
++module_param_named(brs, sysaufs_brs, int, S_IRUGO);
++
++/* ---------------------------------------------------------------------- */
++
++static char au_esc_chars[0x20 + 3]; /* 0x01-0x20, backslash, del, and NULL */
++
++int au_seq_path(struct seq_file *seq, struct path *path)
++{
++	return seq_path(seq, path, au_esc_chars);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int __init aufs_init(void)
++{
++	int err, i;
++	char *p;
++
++	p = au_esc_chars;
++	for (i = 1; i <= ' '; i++)
++		*p++ = i;
++	*p++ = '\\';
++	*p++ = '\x7f';
++	*p = 0;
++
++	au_dir_roflags = au_file_roflags(O_DIRECTORY | O_LARGEFILE);
++
++	sysaufs_brs_init();
++	au_debug_init();
++
++	err = -EINVAL;
++	if (unlikely(aufs_nwkq <= 0))
++		goto out;
++
++	err = sysaufs_init();
++	if (unlikely(err))
++		goto out;
++	err = au_wkq_init();
++	if (unlikely(err))
++		goto out_sysaufs;
++	err = au_hinotify_init();
++	if (unlikely(err))
++		goto out_wkq;
++	err = au_sysrq_init();
++	if (unlikely(err))
++		goto out_hin;
++	err = au_cache_init();
++	if (unlikely(err))
++		goto out_sysrq;
++	err = register_filesystem(&aufs_fs_type);
++	if (unlikely(err))
++		goto out_cache;
++	pr_info(AUFS_NAME " " AUFS_VERSION "\n");
++	goto out; /* success */
++
++ out_cache:
++	au_cache_fin();
++ out_sysrq:
++	au_sysrq_fin();
++ out_hin:
++	au_hinotify_fin();
++ out_wkq:
++	au_wkq_fin();
++ out_sysaufs:
++	sysaufs_fin();
++ out:
++	return err;
++}
++
++static void __exit aufs_exit(void)
++{
++	unregister_filesystem(&aufs_fs_type);
++	au_cache_fin();
++	au_sysrq_fin();
++	au_hinotify_fin();
++	au_wkq_fin();
++	sysaufs_fin();
++}
++
++module_init(aufs_init);
++module_exit(aufs_exit);
+diff -uNr test/fs/aufs/module.h aufs2-standalone/fs/aufs/module.h
+--- test/fs/aufs/module.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/module.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,66 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * module initialization and module-global
++ */
++
++#ifndef __AUFS_MODULE_H__
++#define __AUFS_MODULE_H__
++
++#ifdef __KERNEL__
++
++#include <linux/slab.h>
++
++/* module parameters */
++extern short aufs_nwkq;
++extern int sysaufs_brs;
++
++/* ---------------------------------------------------------------------- */
++
++extern int au_dir_roflags;
++
++void *au_kzrealloc(void *p, unsigned int nused, unsigned int new_sz, gfp_t gfp);
++int au_seq_path(struct seq_file *seq, struct path *path);
++
++/* ---------------------------------------------------------------------- */
++
++/* kmem cache */
++enum {
++	AuCache_DINFO,
++	AuCache_ICNTNR,
++	AuCache_FINFO,
++	AuCache_VDIR,
++	AuCache_DEHSTR,
++#ifdef CONFIG_AUFS_HINOTIFY
++	AuCache_HINOTIFY,
++#endif
++	AuCache_Last
++};
++
++#define AuCache(type)	KMEM_CACHE(type, SLAB_RECLAIM_ACCOUNT)
++
++extern struct kmem_cache *au_cachep[];
++
++#define AuCacheFuncs(name, index) \
++static inline void *au_cache_alloc_##name(void) \
++{ return kmem_cache_alloc(au_cachep[AuCache_##index], GFP_NOFS); } \
++static inline void au_cache_free_##name(void *p) \
++{ kmem_cache_free(au_cachep[AuCache_##index], p); }
++
++AuCacheFuncs(dinfo, DINFO);
++AuCacheFuncs(icntnr, ICNTNR);
++AuCacheFuncs(finfo, FINFO);
++AuCacheFuncs(vdir, VDIR);
++AuCacheFuncs(dehstr, DEHSTR);
++
++/*  ---------------------------------------------------------------------- */
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_MODULE_H__ */
+diff -uNr test/fs/aufs/opts.c aufs2-standalone/fs/aufs/opts.c
+--- test/fs/aufs/opts.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/opts.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,1438 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * mount options/flags
++ */
++
++#include <linux/types.h> /* a distribution requires */
++#include <linux/parser.h>
++#include "aufs.h"
++
++/* ---------------------------------------------------------------------- */
++
++enum {
++	Opt_br,
++	Opt_add, Opt_del, Opt_mod, Opt_reorder, Opt_append, Opt_prepend,
++	Opt_idel, Opt_imod, Opt_ireorder,
++	Opt_dirwh, Opt_rdcache, Opt_deblk, Opt_nhash, Opt_rendir,
++	Opt_xino, Opt_zxino, Opt_noxino,
++	Opt_trunc_xino, Opt_trunc_xino_v, Opt_notrunc_xino,
++	Opt_trunc_xino_path, Opt_itrunc_xino,
++	Opt_trunc_xib, Opt_notrunc_xib,
++	Opt_plink, Opt_noplink, Opt_list_plink,
++	Opt_udba,
++	/* Opt_lock, Opt_unlock, */
++	Opt_cmd, Opt_cmd_args,
++	Opt_diropq_a, Opt_diropq_w,
++	Opt_warn_perm, Opt_nowarn_perm,
++	Opt_wbr_copyup, Opt_wbr_create,
++	Opt_refrof, Opt_norefrof,
++	Opt_verbose, Opt_noverbose,
++	Opt_sum, Opt_nosum, Opt_wsum,
++	Opt_tail, Opt_ignore, Opt_ignore_silent, Opt_err
++};
++
++static match_table_t options = {
++	{Opt_br, "br=%s"},
++	{Opt_br, "br:%s"},
++
++	{Opt_add, "add=%d:%s"},
++	{Opt_add, "add:%d:%s"},
++	{Opt_add, "ins=%d:%s"},
++	{Opt_add, "ins:%d:%s"},
++	{Opt_append, "append=%s"},
++	{Opt_append, "append:%s"},
++	{Opt_prepend, "prepend=%s"},
++	{Opt_prepend, "prepend:%s"},
++
++	{Opt_del, "del=%s"},
++	{Opt_del, "del:%s"},
++	/* {Opt_idel, "idel:%d"}, */
++	{Opt_mod, "mod=%s"},
++	{Opt_mod, "mod:%s"},
++	/* {Opt_imod, "imod:%d:%s"}, */
++
++	{Opt_dirwh, "dirwh=%d"},
++
++	{Opt_xino, "xino=%s"},
++	{Opt_noxino, "noxino"},
++	{Opt_trunc_xino, "trunc_xino"},
++	{Opt_trunc_xino_v, "trunc_xino_v=%d:%d"},
++	{Opt_notrunc_xino, "notrunc_xino"},
++	{Opt_trunc_xino_path, "trunc_xino=%s"},
++	{Opt_itrunc_xino, "itrunc_xino=%d"},
++	/* {Opt_zxino, "zxino=%s"}, */
++	{Opt_trunc_xib, "trunc_xib"},
++	{Opt_notrunc_xib, "notrunc_xib"},
++
++	{Opt_plink, "plink"},
++	{Opt_noplink, "noplink"},
++#ifdef CONFIG_AUFS_DEBUG
++	{Opt_list_plink, "list_plink"},
++#endif
++
++	{Opt_udba, "udba=%s"},
++
++	{Opt_diropq_a, "diropq=always"},
++	{Opt_diropq_a, "diropq=a"},
++	{Opt_diropq_w, "diropq=whiteouted"},
++	{Opt_diropq_w, "diropq=w"},
++
++	{Opt_warn_perm, "warn_perm"},
++	{Opt_nowarn_perm, "nowarn_perm"},
++
++	/* keep them temporary */
++	{Opt_ignore_silent, "coo=%s"},
++	{Opt_ignore_silent, "nodlgt"},
++	{Opt_ignore_silent, "nodirperm1"},
++	{Opt_ignore_silent, "noshwh"},
++	{Opt_ignore_silent, "noshwh"},
++	{Opt_ignore_silent, "clean_plink"},
++
++	{Opt_rendir, "rendir=%d"},
++
++	{Opt_refrof, "refrof"},
++	{Opt_norefrof, "norefrof"},
++
++	{Opt_verbose, "verbose"},
++	{Opt_verbose, "v"},
++	{Opt_noverbose, "noverbose"},
++	{Opt_noverbose, "quiet"},
++	{Opt_noverbose, "q"},
++	{Opt_noverbose, "silent"},
++
++	{Opt_sum, "sum"},
++	{Opt_nosum, "nosum"},
++	{Opt_wsum, "wsum"},
++
++	{Opt_rdcache, "rdcache=%d"},
++	{Opt_rdcache, "rdcache:%d"},
++
++	{Opt_wbr_create, "create=%s"},
++	{Opt_wbr_create, "create_policy=%s"},
++	{Opt_wbr_copyup, "cpup=%s"},
++	{Opt_wbr_copyup, "copyup=%s"},
++	{Opt_wbr_copyup, "copyup_policy=%s"},
++
++	/* internal use for the scripts */
++	{Opt_ignore_silent, "si=%s"},
++
++	{Opt_br, "dirs=%s"},
++	{Opt_ignore, "debug=%d"},
++	{Opt_ignore, "delete=whiteout"},
++	{Opt_ignore, "delete=all"},
++	{Opt_ignore, "imap=%s"},
++
++	{Opt_err, NULL}
++};
++
++/* ---------------------------------------------------------------------- */
++
++static const char *au_parser_pattern(int val, struct match_token *token)
++{
++	while (token->pattern) {
++		if (token->token == val)
++			return token->pattern;
++		token++;
++	}
++	BUG();
++	return "??";
++}
++
++/* ---------------------------------------------------------------------- */
++
++static match_table_t brperms = {
++	{AuBrPerm_RO, AUFS_BRPERM_RO},
++	{AuBrPerm_RR, AUFS_BRPERM_RR},
++	{AuBrPerm_RW, AUFS_BRPERM_RW},
++
++	{AuBrPerm_ROWH, AUFS_BRPERM_ROWH},
++	{AuBrPerm_RRWH, AUFS_BRPERM_RRWH},
++	{AuBrPerm_RWNoLinkWH, AUFS_BRPERM_RWNLWH},
++
++	{AuBrPerm_ROWH, "nfsro"},
++	{AuBrPerm_RO, NULL}
++};
++
++static int br_perm_val(char *perm)
++{
++	int val;
++	substring_t args[MAX_OPT_ARGS];
++
++	val = match_token(perm, brperms, args);
++	return val;
++}
++
++const char *au_optstr_br_perm(int brperm)
++{
++	return au_parser_pattern(brperm, (void *)brperms);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static match_table_t udbalevel = {
++	{AuOpt_UDBA_REVAL, "reval"},
++	{AuOpt_UDBA_NONE, "none"},
++#ifdef CONFIG_AUFS_HINOTIFY
++	{AuOpt_UDBA_HINOTIFY, "inotify"},
++#endif
++	{-1, NULL}
++};
++
++static int udba_val(char *str)
++{
++	substring_t args[MAX_OPT_ARGS];
++
++	return match_token(str, udbalevel, args);
++}
++
++const char *au_optstr_udba(int udba)
++{
++	return au_parser_pattern(udba, (void *)udbalevel);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static match_table_t au_wbr_create_policy = {
++	{AuWbrCreate_TDP, "tdp"},
++	{AuWbrCreate_TDP, "top-down-parent"},
++	{AuWbrCreate_RR, "rr"},
++	{AuWbrCreate_RR, "round-robin"},
++	{AuWbrCreate_MFS, "mfs"},
++	{AuWbrCreate_MFS, "most-free-space"},
++	{AuWbrCreate_MFSV, "mfs:%d"},
++	{AuWbrCreate_MFSV, "most-free-space:%d"},
++
++	{AuWbrCreate_MFSRR, "mfsrr:%d"},
++	{AuWbrCreate_MFSRRV, "mfsrr:%d:%d"},
++	{AuWbrCreate_PMFS, "pmfs"},
++	{AuWbrCreate_PMFSV, "pmfs:%d"},
++
++	{-1, NULL}
++};
++
++/* cf. linux/lib/parser.c */
++static int au_match_ull(substring_t *s, unsigned long long *result)
++{
++	int err;
++	unsigned int len;
++	char a[32];
++
++	err = -ERANGE;
++	len = s->to - s->from;
++	if (len + 1 <= sizeof(a)) {
++		memcpy(a, s->from, len);
++		a[len] = '\0';
++		err = strict_strtoull(a, 0, result);
++	}
++	return err;
++}
++
++static int au_wbr_mfs_wmark(substring_t *arg, char *str,
++			    struct au_opt_wbr_create *create)
++{
++	int err;
++	unsigned long long ull;
++
++	err = 0;
++	if (!au_match_ull(arg, &ull))
++		create->mfsrr_watermark = ull;
++	else {
++		AuErr("bad integer in %s\n", str);
++		err = -EINVAL;
++	}
++
++	return err;
++}
++
++static int au_wbr_mfs_sec(substring_t *arg, char *str,
++			  struct au_opt_wbr_create *create)
++{
++	int n, err;
++
++	err = 0;
++	if (!match_int(arg, &n) && 0 <= n)
++		create->mfs_second = n;
++	else {
++		AuErr("bad integer in %s\n", str);
++		err = -EINVAL;
++	}
++
++	return err;
++}
++
++static int au_wbr_create_val(char *str, struct au_opt_wbr_create *create)
++{
++	int err, e;
++	substring_t args[MAX_OPT_ARGS];
++
++	err = match_token(str, au_wbr_create_policy, args);
++	create->wbr_create = err;
++	switch (err) {
++	case AuWbrCreate_MFSRRV:
++		e = au_wbr_mfs_wmark(&args[0], str, create);
++		if (!e)
++			e = au_wbr_mfs_sec(&args[1], str, create);
++		if (unlikely(e))
++			err = e;
++		break;
++	case AuWbrCreate_MFSRR:
++		e = au_wbr_mfs_wmark(&args[0], str, create);
++		if (unlikely(e)) {
++			err = e;
++			break;
++		}
++		/*FALLTHROUGH*/
++	case AuWbrCreate_MFS:
++	case AuWbrCreate_PMFS:
++		create->mfs_second = AUFS_MFS_SECOND_DEF;
++		break;
++	case AuWbrCreate_MFSV:
++	case AuWbrCreate_PMFSV:
++		e = au_wbr_mfs_sec(&args[0], str, create);
++		if (unlikely(e))
++			err = e;
++		break;
++	}
++
++	return err;
++}
++
++const char *au_optstr_wbr_create(int wbr_create)
++{
++	return au_parser_pattern(wbr_create, (void *)au_wbr_create_policy);
++}
++
++static match_table_t au_wbr_copyup_policy = {
++	{AuWbrCopyup_TDP, "tdp"},
++	{AuWbrCopyup_TDP, "top-down-parent"},
++	{AuWbrCopyup_BUP, "bup"},
++	{AuWbrCopyup_BUP, "bottom-up-parent"},
++	{AuWbrCopyup_BU, "bu"},
++	{AuWbrCopyup_BU, "bottom-up"},
++	{-1, NULL}
++};
++
++static int au_wbr_copyup_val(char *str)
++{
++	substring_t args[MAX_OPT_ARGS];
++
++	return match_token(str, au_wbr_copyup_policy, args);
++}
++
++const char *au_optstr_wbr_copyup(int wbr_copyup)
++{
++	return au_parser_pattern(wbr_copyup, (void *)au_wbr_copyup_policy);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static const int lkup_dirflags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
++
++static void dump_opts(struct au_opts *opts)
++{
++#ifdef CONFIG_AUFS_DEBUG
++	/* reduce stack space */
++	union {
++		struct au_opt_add *add;
++		struct au_opt_del *del;
++		struct au_opt_mod *mod;
++		struct au_opt_xino *xino;
++		struct au_opt_xino_itrunc *xino_itrunc;
++		struct au_opt_wbr_create *create;
++	} u;
++	struct au_opt *opt;
++
++	opt = opts->opt;
++	while (opt->type != Opt_tail) {
++		switch (opt->type) {
++		case Opt_add:
++			u.add = &opt->add;
++			AuDbg("add {b%d, %s, 0x%x, %p}\n",
++				  u.add->bindex, u.add->pathname, u.add->perm,
++				  u.add->path.dentry);
++			break;
++		case Opt_del:
++		case Opt_idel:
++			u.del = &opt->del;
++			AuDbg("del {%s, %p}\n",
++			      u.del->pathname, u.del->h_path.dentry);
++			break;
++		case Opt_mod:
++		case Opt_imod:
++			u.mod = &opt->mod;
++			AuDbg("mod {%s, 0x%x, %p}\n",
++				  u.mod->path, u.mod->perm, u.mod->h_root);
++			break;
++		case Opt_append:
++			u.add = &opt->add;
++			AuDbg("append {b%d, %s, 0x%x, %p}\n",
++				  u.add->bindex, u.add->pathname, u.add->perm,
++				  u.add->path.dentry);
++			break;
++		case Opt_prepend:
++			u.add = &opt->add;
++			AuDbg("prepend {b%d, %s, 0x%x, %p}\n",
++				  u.add->bindex, u.add->pathname, u.add->perm,
++				  u.add->path.dentry);
++			break;
++		case Opt_dirwh:
++			AuDbg("dirwh %d\n", opt->dirwh);
++			break;
++		case Opt_rdcache:
++			AuDbg("rdcache %d\n", opt->rdcache);
++			break;
++		case Opt_xino:
++			u.xino = &opt->xino;
++			AuDbg("xino {%s %.*s}\n",
++				  u.xino->path,
++				  AuDLNPair(u.xino->file->f_dentry));
++			break;
++		case Opt_trunc_xino:
++			AuLabel(trunc_xino);
++			break;
++		case Opt_notrunc_xino:
++			AuLabel(notrunc_xino);
++			break;
++		case Opt_trunc_xino_path:
++		case Opt_itrunc_xino:
++			u.xino_itrunc = &opt->xino_itrunc;
++			AuDbg("trunc_xino %d\n", u.xino_itrunc->bindex);
++			break;
++
++		case Opt_noxino:
++			AuLabel(noxino);
++			break;
++		case Opt_trunc_xib:
++			AuLabel(trunc_xib);
++			break;
++		case Opt_notrunc_xib:
++			AuLabel(notrunc_xib);
++			break;
++		case Opt_plink:
++			AuLabel(plink);
++			break;
++		case Opt_noplink:
++			AuLabel(noplink);
++			break;
++		case Opt_list_plink:
++			AuLabel(list_plink);
++			break;
++		case Opt_udba:
++			AuDbg("udba %d, %s\n",
++				  opt->udba, au_optstr_udba(opt->udba));
++			break;
++		case Opt_diropq_a:
++			AuLabel(diropq_a);
++			break;
++		case Opt_diropq_w:
++			AuLabel(diropq_w);
++			break;
++		case Opt_warn_perm:
++			AuLabel(warn_perm);
++			break;
++		case Opt_nowarn_perm:
++			AuLabel(nowarn_perm);
++			break;
++		case Opt_refrof:
++			AuLabel(refrof);
++			break;
++		case Opt_norefrof:
++			AuLabel(norefrof);
++			break;
++		case Opt_verbose:
++			AuLabel(verbose);
++			break;
++		case Opt_noverbose:
++			AuLabel(noverbose);
++			break;
++		case Opt_sum:
++			AuLabel(sum);
++			break;
++		case Opt_nosum:
++			AuLabel(nosum);
++			break;
++		case Opt_wsum:
++			AuLabel(wsum);
++			break;
++		case Opt_wbr_create:
++			u.create = &opt->wbr_create;
++			AuDbg("create %d, %s\n", u.create->wbr_create,
++				  au_optstr_wbr_create(u.create->wbr_create));
++			switch (u.create->wbr_create) {
++			case AuWbrCreate_MFSV:
++			case AuWbrCreate_PMFSV:
++				AuDbg("%d sec\n", u.create->mfs_second);
++				break;
++			case AuWbrCreate_MFSRR:
++				AuDbg("%llu watermark\n",
++					  u.create->mfsrr_watermark);
++				break;
++			case AuWbrCreate_MFSRRV:
++				AuDbg("%llu watermark, %d sec\n",
++					  u.create->mfsrr_watermark,
++					  u.create->mfs_second);
++				break;
++			}
++			break;
++		case Opt_wbr_copyup:
++			AuDbg("copyup %d, %s\n", opt->wbr_copyup,
++				  au_optstr_wbr_copyup(opt->wbr_copyup));
++			break;
++		default:
++			BUG();
++		}
++		opt++;
++	}
++#endif
++}
++
++void au_opts_free(struct au_opts *opts)
++{
++	struct au_opt *opt;
++
++	opt = opts->opt;
++	while (opt->type != Opt_tail) {
++		switch (opt->type) {
++		case Opt_add:
++		case Opt_append:
++		case Opt_prepend:
++			path_put(&opt->add.path);
++			break;
++		case Opt_del:
++		case Opt_idel:
++			path_put(&opt->del.h_path);
++			break;
++		case Opt_mod:
++		case Opt_imod:
++			dput(opt->mod.h_root);
++			break;
++		case Opt_xino:
++			fput(opt->xino.file);
++			break;
++		}
++		opt++;
++	}
++}
++
++static int opt_add(struct au_opt *opt, char *opt_str, unsigned long sb_flags,
++		   aufs_bindex_t bindex)
++{
++	int err;
++	struct au_opt_add *add = &opt->add;
++	char *p;
++
++	add->bindex = bindex;
++	add->perm = AuBrPerm_Last;
++	add->pathname = opt_str;
++	p = strchr(opt_str, '=');
++	if (p) {
++		*p++ = 0;
++		if (*p)
++			add->perm = br_perm_val(p);
++	}
++
++	err = vfsub_kern_path(add->pathname, lkup_dirflags, &add->path);
++	if (!err) {
++		if (!p) {
++			add->perm = AuBrPerm_RO;
++			if (au_test_fs_rr(add->path.dentry->d_sb))
++				add->perm = AuBrPerm_RR;
++			else if (!bindex && !(sb_flags & MS_RDONLY))
++				add->perm = AuBrPerm_RW;
++		}
++		opt->type = Opt_add;
++		goto out;
++	}
++	AuErr("lookup failed %s (%d)\n", add->pathname, err);
++	err = -EINVAL;
++
++ out:
++	return err;
++}
++
++static int au_opts_parse_del(struct au_opt_del *del, substring_t args[])
++{
++	int err;
++
++	del->pathname = args[0].from;
++	AuDbg("del path %s\n", del->pathname);
++
++	err = vfsub_kern_path(del->pathname, lkup_dirflags, &del->h_path);
++	if (unlikely(err))
++		AuErr("lookup failed %s (%d)\n", del->pathname, err);
++
++	return err;
++}
++
++#if 0 /* reserved for future use */
++static int au_opts_parse_idel(struct super_block *sb, aufs_bindex_t bindex,
++			      struct au_opt_del *del, substring_t args[])
++{
++	int err;
++	struct dentry *root;
++
++	err = -EINVAL;
++	root = sb->s_root;
++	aufs_read_lock(root, AuLock_FLUSH);
++	if (bindex < 0 || au_sbend(sb) < bindex) {
++		AuErr("out of bounds, %d\n", bindex);
++		goto out;
++	}
++
++	err = 0;
++	del->h_path.dentry = dget(au_h_dptr(root, bindex));
++	del->h_path.mnt = mntget(au_sbr_mnt(sb, bindex));
++
++ out:
++	aufs_read_unlock(root, !AuLock_IR);
++	return err;
++}
++#endif
++
++static int au_opts_parse_mod(struct au_opt_mod *mod, substring_t args[])
++{
++	int err;
++	struct path path;
++	char *p;
++
++	err = -EINVAL;
++	mod->path = args[0].from;
++	p = strchr(mod->path, '=');
++	if (unlikely(!p)) {
++		AuErr("no permssion %s\n", args[0].from);
++		goto out;
++	}
++
++	*p++ = 0;
++	err = vfsub_kern_path(mod->path, lkup_dirflags, &path);
++	if (unlikely(err)) {
++		AuErr("lookup failed %s (%d)\n", mod->path, err);
++		goto out;
++	}
++
++	mod->perm = br_perm_val(p);
++	AuDbg("mod path %s, perm 0x%x, %s\n", mod->path, mod->perm, p);
++	mod->h_root = dget(path.dentry);
++	path_put(&path);
++
++ out:
++	return err;
++}
++
++#if 0 /* reserved for future use */
++static int au_opts_parse_imod(struct super_block *sb, aufs_bindex_t bindex,
++			      struct au_opt_mod *mod, substring_t args[])
++{
++	int err;
++	struct dentry *root;
++
++	err = -EINVAL;
++	root = sb->s_root;
++	aufs_read_lock(root, AuLock_FLUSH);
++	if (bindex < 0 || au_sbend(sb) < bindex) {
++		AuErr("out of bounds, %d\n", bindex);
++		goto out;
++	}
++
++	err = 0;
++	mod->perm = br_perm_val(args[1].from);
++	AuDbg("mod path %s, perm 0x%x, %s\n",
++	      mod->path, mod->perm, args[1].from);
++	mod->h_root = dget(au_h_dptr(root, bindex));
++
++ out:
++	aufs_read_unlock(root, !AuLock_IR);
++	return err;
++}
++#endif
++
++static int au_opts_parse_xino(struct super_block *sb, struct au_opt_xino *xino,
++			      substring_t args[])
++{
++	int err;
++	struct file *file;
++
++	file = au_xino_create(sb, args[0].from, /*silent*/0);
++	err = PTR_ERR(file);
++	if (IS_ERR(file))
++		goto out;
++
++	err = -EINVAL;
++	if (unlikely(file->f_dentry->d_sb == sb)) {
++		fput(file);
++		AuErr("%s must be outside\n", args[0].from);
++		goto out;
++	}
++
++	err = 0;
++	xino->file = file;
++	xino->path = args[0].from;
++
++ out:
++	return err;
++}
++
++static
++int au_opts_parse_xino_itrunc_path(struct super_block *sb,
++				   struct au_opt_xino_itrunc *xino_itrunc,
++				   substring_t args[])
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct path path;
++	struct dentry *root;
++
++	err = vfsub_kern_path(args[0].from, lkup_dirflags, &path);
++	if (unlikely(err)) {
++		AuErr("lookup failed %s (%d)\n", args[0].from, err);
++		goto out;
++	}
++
++	xino_itrunc->bindex = -1;
++	root = sb->s_root;
++	aufs_read_lock(root, AuLock_FLUSH);
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++) {
++		if (au_h_dptr(root, bindex) == path.dentry) {
++			xino_itrunc->bindex = bindex;
++			break;
++		}
++	}
++	aufs_read_unlock(root, !AuLock_IR);
++	path_put(&path);
++
++	if (unlikely(xino_itrunc->bindex < 0)) {
++		AuErr("no such branch %s\n", args[0].from);
++		err = -EINVAL;
++	}
++
++ out:
++	return err;
++}
++
++/* called without aufs lock */
++int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts)
++{
++	int err, n, token;
++	aufs_bindex_t bindex;
++	unsigned char skipped;
++	struct dentry *root;
++	struct au_opt *opt, *opt_tail;
++	char *opt_str;
++	/* reduce the stack space */
++	union {
++		struct au_opt_xino_itrunc *xino_itrunc;
++		struct au_opt_wbr_create *create;
++	} u;
++	struct {
++		substring_t args[MAX_OPT_ARGS];
++	} *a;
++
++	err = -ENOMEM;
++	a = kmalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	root = sb->s_root;
++	err = 0;
++	bindex = 0;
++	opt = opts->opt;
++	opt_tail = opt + opts->max_opt - 1;
++	opt->type = Opt_tail;
++	while (!err && (opt_str = strsep(&str, ",")) && *opt_str) {
++		err = -EINVAL;
++		skipped = 0;
++		token = match_token(opt_str, options, a->args);
++		switch (token) {
++		case Opt_br:
++			err = 0;
++			while (!err && (opt_str = strsep(&a->args[0].from, ":"))
++			       && *opt_str) {
++				err = opt_add(opt, opt_str, opts->sb_flags,
++					      bindex++);
++				if (unlikely(!err && ++opt > opt_tail)) {
++					err = -E2BIG;
++					break;
++				}
++				opt->type = Opt_tail;
++				skipped = 1;
++			}
++			break;
++		case Opt_add:
++			if (unlikely(match_int(&a->args[0], &n))) {
++				AuErr("bad integer in %s\n", opt_str);
++				break;
++			}
++			bindex = n;
++			err = opt_add(opt, a->args[1].from, opts->sb_flags,
++				      bindex);
++			if (!err)
++				opt->type = token;
++			break;
++		case Opt_append:
++			err = opt_add(opt, a->args[0].from, opts->sb_flags,
++				      /*dummy bindex*/1);
++			if (!err)
++				opt->type = token;
++			break;
++		case Opt_prepend:
++			err = opt_add(opt, a->args[0].from, opts->sb_flags,
++				      /*bindex*/0);
++			if (!err)
++				opt->type = token;
++			break;
++		case Opt_del:
++			err = au_opts_parse_del(&opt->del, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++#if 0 /* reserved for future use */
++		case Opt_idel:
++			del->pathname = "(indexed)";
++			if (unlikely(match_int(&args[0], &n))) {
++				AuErr("bad integer in %s\n", opt_str);
++				break;
++			}
++			err = au_opts_parse_idel(sb, n, &opt->del, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++#endif
++		case Opt_mod:
++			err = au_opts_parse_mod(&opt->mod, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++#ifdef IMOD /* reserved for future use */
++		case Opt_imod:
++			u.mod->path = "(indexed)";
++			if (unlikely(match_int(&a->args[0], &n))) {
++				AuErr("bad integer in %s\n", opt_str);
++				break;
++			}
++			err = au_opts_parse_imod(sb, n, &opt->mod, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++#endif
++		case Opt_xino:
++			err = au_opts_parse_xino(sb, &opt->xino, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++
++		case Opt_trunc_xino_path:
++			err = au_opts_parse_xino_itrunc_path
++				(sb, &opt->xino_itrunc, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++
++		case Opt_itrunc_xino:
++			u.xino_itrunc = &opt->xino_itrunc;
++			if (unlikely(match_int(&a->args[0], &n))) {
++				AuErr("bad integer in %s\n", opt_str);
++				break;
++			}
++			u.xino_itrunc->bindex = n;
++			aufs_read_lock(root, AuLock_FLUSH);
++			if (n < 0 || au_sbend(sb) < n) {
++				AuErr("out of bounds, %d\n", n);
++				aufs_read_unlock(root, !AuLock_IR);
++				break;
++			}
++			aufs_read_unlock(root, !AuLock_IR);
++			err = 0;
++			opt->type = token;
++			break;
++
++		case Opt_dirwh:
++			if (unlikely(match_int(&a->args[0], &opt->dirwh)))
++				break;
++			err = 0;
++			opt->type = token;
++			break;
++
++		case Opt_rdcache:
++			if (unlikely(match_int(&a->args[0], &opt->rdcache)))
++				break;
++			err = 0;
++			opt->type = token;
++			break;
++
++		case Opt_trunc_xino:
++		case Opt_notrunc_xino:
++		case Opt_noxino:
++		case Opt_trunc_xib:
++		case Opt_notrunc_xib:
++		case Opt_plink:
++		case Opt_noplink:
++		case Opt_list_plink:
++		case Opt_diropq_a:
++		case Opt_diropq_w:
++		case Opt_warn_perm:
++		case Opt_nowarn_perm:
++		case Opt_refrof:
++		case Opt_norefrof:
++		case Opt_verbose:
++		case Opt_noverbose:
++		case Opt_sum:
++		case Opt_nosum:
++		case Opt_wsum:
++			err = 0;
++			opt->type = token;
++			break;
++
++		case Opt_udba:
++			opt->udba = udba_val(a->args[0].from);
++			if (opt->udba >= 0) {
++				err = 0;
++				opt->type = token;
++			} else
++				AuErr("wrong value, %s\n", opt_str);
++			break;
++
++		case Opt_wbr_create:
++			u.create = &opt->wbr_create;
++			u.create->wbr_create
++				= au_wbr_create_val(a->args[0].from, u.create);
++			if (u.create->wbr_create >= 0) {
++				err = 0;
++				opt->type = token;
++			} else
++				AuErr("wrong value, %s\n", opt_str);
++			break;
++		case Opt_wbr_copyup:
++			opt->wbr_copyup = au_wbr_copyup_val(a->args[0].from);
++			if (opt->wbr_copyup >= 0) {
++				err = 0;
++				opt->type = token;
++			} else
++				AuErr("wrong value, %s\n", opt_str);
++			break;
++
++		case Opt_ignore:
++			AuWarn("ignored %s\n", opt_str);
++			/*FALLTHROUGH*/
++		case Opt_ignore_silent:
++			skipped = 1;
++			err = 0;
++			break;
++		case Opt_err:
++			AuErr("unknown option %s\n", opt_str);
++			break;
++		}
++
++		if (!err && !skipped) {
++			if (unlikely(++opt > opt_tail)) {
++				err = -E2BIG;
++				opt--;
++				opt->type = Opt_tail;
++				break;
++			}
++			opt->type = Opt_tail;
++		}
++	}
++
++	kfree(a);
++	dump_opts(opts);
++	if (unlikely(err))
++		au_opts_free(opts);
++
++ out:
++	return err;
++}
++
++static int au_opt_wbr_create(struct super_block *sb,
++			     struct au_opt_wbr_create *create)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++
++	err = 1; /* handled */
++	sbinfo = au_sbi(sb);
++	if (sbinfo->si_wbr_create_ops->fin) {
++		err = sbinfo->si_wbr_create_ops->fin(sb);
++		if (!err)
++			err = 1;
++	}
++
++	sbinfo->si_wbr_create = create->wbr_create;
++	sbinfo->si_wbr_create_ops = au_wbr_create_ops + create->wbr_create;
++	switch (create->wbr_create) {
++	case AuWbrCreate_MFSRRV:
++	case AuWbrCreate_MFSRR:
++		sbinfo->si_wbr_mfs.mfsrr_watermark = create->mfsrr_watermark;
++		/*FALLTHROUGH*/
++	case AuWbrCreate_MFS:
++	case AuWbrCreate_MFSV:
++	case AuWbrCreate_PMFS:
++	case AuWbrCreate_PMFSV:
++		sbinfo->si_wbr_mfs.mfs_expire = create->mfs_second * HZ;
++		break;
++	}
++
++	if (sbinfo->si_wbr_create_ops->init)
++		sbinfo->si_wbr_create_ops->init(sb); /* ignore */
++
++	return err;
++}
++
++/*
++ * returns,
++ * plus: processed without an error
++ * zero: unprocessed
++ */
++static int au_opt_simple(struct super_block *sb, struct au_opt *opt,
++			 struct au_opts *opts)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++
++	err = 1; /* handled */
++	sbinfo = au_sbi(sb);
++	switch (opt->type) {
++	case Opt_udba:
++		sbinfo->si_mntflags &= ~AuOptMask_UDBA;
++		sbinfo->si_mntflags |= opt->udba;
++		opts->given_udba |= opt->udba;
++		break;
++
++	case Opt_plink:
++		au_opt_set(sbinfo->si_mntflags, PLINK);
++		break;
++	case Opt_noplink:
++		if (au_opt_test(sbinfo->si_mntflags, PLINK))
++			au_plink_put(sb);
++		au_opt_clr(sbinfo->si_mntflags, PLINK);
++		break;
++	case Opt_list_plink:
++		if (au_opt_test(sbinfo->si_mntflags, PLINK))
++			au_plink_list(sb);
++		break;
++
++	case Opt_diropq_a:
++		au_opt_set(sbinfo->si_mntflags, ALWAYS_DIROPQ);
++		break;
++	case Opt_diropq_w:
++		au_opt_clr(sbinfo->si_mntflags, ALWAYS_DIROPQ);
++		break;
++
++	case Opt_warn_perm:
++		au_opt_set(sbinfo->si_mntflags, WARN_PERM);
++		break;
++	case Opt_nowarn_perm:
++		au_opt_clr(sbinfo->si_mntflags, WARN_PERM);
++		break;
++
++	case Opt_refrof:
++		au_opt_set(sbinfo->si_mntflags, REFROF);
++		break;
++	case Opt_norefrof:
++		au_opt_clr(sbinfo->si_mntflags, REFROF);
++		break;
++
++	case Opt_verbose:
++		au_opt_set(sbinfo->si_mntflags, VERBOSE);
++		break;
++	case Opt_noverbose:
++		au_opt_clr(sbinfo->si_mntflags, VERBOSE);
++		break;
++
++	case Opt_sum:
++		au_opt_set(sbinfo->si_mntflags, SUM);
++		break;
++	case Opt_wsum:
++		au_opt_clr(sbinfo->si_mntflags, SUM);
++		au_opt_set(sbinfo->si_mntflags, SUM_W);
++	case Opt_nosum:
++		au_opt_clr(sbinfo->si_mntflags, SUM);
++		au_opt_clr(sbinfo->si_mntflags, SUM_W);
++		break;
++
++	case Opt_wbr_create:
++		err = au_opt_wbr_create(sb, &opt->wbr_create);
++		break;
++	case Opt_wbr_copyup:
++		sbinfo->si_wbr_copyup = opt->wbr_copyup;
++		sbinfo->si_wbr_copyup_ops = au_wbr_copyup_ops + opt->wbr_copyup;
++		break;
++
++	case Opt_dirwh:
++		sbinfo->si_dirwh = opt->dirwh;
++		break;
++
++	case Opt_rdcache:
++		sbinfo->si_rdcache = opt->rdcache * HZ;
++		break;
++
++	case Opt_trunc_xino:
++		au_opt_set(sbinfo->si_mntflags, TRUNC_XINO);
++		break;
++	case Opt_notrunc_xino:
++		au_opt_clr(sbinfo->si_mntflags, TRUNC_XINO);
++		break;
++
++	case Opt_trunc_xino_path:
++	case Opt_itrunc_xino:
++		err = au_xino_trunc(sb, opt->xino_itrunc.bindex);
++		if (!err)
++			err = 1;
++		break;
++
++	case Opt_trunc_xib:
++		au_fset_opts(opts->flags, TRUNC_XIB);
++		break;
++	case Opt_notrunc_xib:
++		au_fclr_opts(opts->flags, TRUNC_XIB);
++		break;
++
++	default:
++		err = 0;
++		break;
++	}
++
++	return err;
++}
++
++/*
++ * returns tri-state.
++ * plus: processed without an error
++ * zero: unprocessed
++ * minus: error
++ */
++static int au_opt_br(struct super_block *sb, struct au_opt *opt,
++		     struct au_opts *opts)
++{
++	int err, do_refresh;
++
++	err = 0;
++	switch (opt->type) {
++	case Opt_append:
++		opt->add.bindex = au_sbend(sb) + 1;
++		if (opt->add.bindex < 0)
++			opt->add.bindex = 0;
++		goto add;
++	case Opt_prepend:
++		opt->add.bindex = 0;
++	add:
++	case Opt_add:
++		err = au_br_add(sb, &opt->add,
++				au_ftest_opts(opts->flags, REMOUNT));
++		if (!err) {
++			err = 1;
++			au_fset_opts(opts->flags, REFRESH_DIR);
++			if (au_br_whable(opt->add.perm))
++				au_fset_opts(opts->flags, REFRESH_NONDIR);
++		}
++		break;
++
++	case Opt_del:
++	case Opt_idel:
++		err = au_br_del(sb, &opt->del,
++				au_ftest_opts(opts->flags, REMOUNT));
++		if (!err) {
++			err = 1;
++			au_fset_opts(opts->flags, TRUNC_XIB);
++			au_fset_opts(opts->flags, REFRESH_DIR);
++			au_fset_opts(opts->flags, REFRESH_NONDIR);
++		}
++		break;
++
++	case Opt_mod:
++	case Opt_imod:
++		err = au_br_mod(sb, &opt->mod,
++				au_ftest_opts(opts->flags, REMOUNT),
++				&do_refresh);
++		if (!err) {
++			err = 1;
++			if (do_refresh) {
++				au_fset_opts(opts->flags, REFRESH_DIR);
++				au_fset_opts(opts->flags, REFRESH_NONDIR);
++			}
++		}
++		break;
++	}
++
++	return err;
++}
++
++static int au_opt_xino(struct super_block *sb, struct au_opt *opt,
++		       struct au_opt_xino **opt_xino,
++		       struct au_opts *opts)
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct dentry *root, *parent, *h_root;
++
++	err = 0;
++	switch (opt->type) {
++	case Opt_xino:
++		err = au_xino_set(sb, &opt->xino,
++				  !!au_ftest_opts(opts->flags, REMOUNT));
++		if (unlikely(err))
++			break;
++
++		*opt_xino = &opt->xino;
++		au_xino_brid_set(sb, -1);
++
++		/* safe d_parent access */
++		parent = opt->xino.file->f_dentry->d_parent;
++		root = sb->s_root;
++		bend = au_sbend(sb);
++		for (bindex = 0; bindex <= bend; bindex++) {
++			h_root = au_h_dptr(root, bindex);
++			if (h_root == parent) {
++				au_xino_brid_set(sb, au_sbr_id(sb, bindex));
++				break;
++			}
++		}
++		break;
++
++	case Opt_noxino:
++		au_xino_clr(sb);
++		au_xino_brid_set(sb, -1);
++		*opt_xino = (void *)-1;
++		break;
++	}
++
++	return err;
++}
++
++int au_opts_verify(struct super_block *sb, unsigned long sb_flags,
++		   unsigned int pending)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	unsigned char do_plink, skip, do_free;
++	struct au_branch *br;
++	struct au_wbr *wbr;
++	struct dentry *root;
++	struct inode *dir, *h_dir;
++	struct au_sbinfo *sbinfo;
++	struct au_hinode *hdir;
++
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!(sbinfo->si_mntflags & AuOptMask_UDBA));
++
++	if (unlikely(!(sb_flags & MS_RDONLY)
++		     && !au_br_writable(au_sbr_perm(sb, 0))))
++		AuWarn("first branch should be rw\n");
++
++	if (au_opt_test((sbinfo->si_mntflags | pending), UDBA_HINOTIFY)
++	    && !au_opt_test(sbinfo->si_mntflags, XINO))
++		AuWarn("udba=inotify requires xino\n");
++
++	err = 0;
++	root = sb->s_root;
++	dir = sb->s_root->d_inode;
++	do_plink = !!au_opt_test(sbinfo->si_mntflags, PLINK);
++	bend = au_sbend(sb);
++	for (bindex = 0; !err && bindex <= bend; bindex++) {
++		skip = 0;
++		h_dir = au_h_iptr(dir, bindex);
++		br = au_sbr(sb, bindex);
++		do_free = 0;
++
++		wbr = br->br_wbr;
++		if (wbr)
++			wbr_wh_read_lock(wbr);
++
++		switch (br->br_perm) {
++		case AuBrPerm_RO:
++		case AuBrPerm_ROWH:
++		case AuBrPerm_RR:
++		case AuBrPerm_RRWH:
++			do_free = !!wbr;
++			skip = (!wbr
++				|| (!wbr->wbr_whbase
++				    && !wbr->wbr_plink
++				    && !wbr->wbr_orph));
++			break;
++
++		case AuBrPerm_RWNoLinkWH:
++			/* skip = (!br->br_whbase && !br->br_orph); */
++			skip = (!wbr || !wbr->wbr_whbase);
++			if (skip && wbr) {
++				if (do_plink)
++					skip = !!wbr->wbr_plink;
++				else
++					skip = !wbr->wbr_plink;
++			}
++			break;
++
++		case AuBrPerm_RW:
++			/* skip = (br->br_whbase && br->br_ohph); */
++			skip = (wbr && wbr->wbr_whbase);
++			if (skip) {
++				if (do_plink)
++					skip = !!wbr->wbr_plink;
++				else
++					skip = !wbr->wbr_plink;
++			}
++			break;
++
++		default:
++			BUG();
++		}
++		if (wbr)
++			wbr_wh_read_unlock(wbr);
++
++		if (skip)
++			continue;
++
++		hdir = au_hi(dir, bindex);
++		au_hin_imtx_lock_nested(hdir, AuLsc_I_PARENT);
++		if (wbr)
++			wbr_wh_write_lock(wbr);
++		err = au_wh_init(au_h_dptr(root, bindex), br, sb);
++		if (wbr)
++			wbr_wh_write_unlock(wbr);
++		au_hin_imtx_unlock(hdir);
++
++		if (!err && do_free) {
++			kfree(wbr);
++			br->br_wbr = NULL;
++		}
++	}
++
++	return err;
++}
++
++int au_opts_mount(struct super_block *sb, struct au_opts *opts)
++{
++	int err;
++	unsigned int tmp;
++	aufs_bindex_t bend;
++	struct au_opt *opt;
++	struct au_opt_xino *opt_xino, xino;
++	struct au_sbinfo *sbinfo;
++
++	err = 0;
++	opt_xino = NULL;
++	opt = opts->opt;
++	while (err >= 0 && opt->type != Opt_tail)
++		err = au_opt_simple(sb, opt++, opts);
++	if (err > 0)
++		err = 0;
++	else if (unlikely(err < 0))
++		goto out;
++
++	/* disable xino and udba temporary */
++	sbinfo = au_sbi(sb);
++	tmp = sbinfo->si_mntflags;
++	au_opt_clr(sbinfo->si_mntflags, XINO);
++	au_opt_set_udba(sbinfo->si_mntflags, UDBA_REVAL);
++
++	opt = opts->opt;
++	while (err >= 0 && opt->type != Opt_tail)
++		err = au_opt_br(sb, opt++, opts);
++	if (err > 0)
++		err = 0;
++	else if (unlikely(err < 0))
++		goto out;
++
++	bend = au_sbend(sb);
++	if (unlikely(bend < 0)) {
++		err = -EINVAL;
++		AuErr("no branches\n");
++		goto out;
++	}
++
++	if (au_opt_test(tmp, XINO))
++		au_opt_set(sbinfo->si_mntflags, XINO);
++	opt = opts->opt;
++	while (!err && opt->type != Opt_tail)
++		err = au_opt_xino(sb, opt++, &opt_xino, opts);
++	if (unlikely(err))
++		goto out;
++
++	err = au_opts_verify(sb, sb->s_flags, tmp);
++	if (unlikely(err))
++		goto out;
++
++	/* restore xino */
++	if (au_opt_test(tmp, XINO) && !opt_xino) {
++		xino.file = au_xino_def(sb);
++		err = PTR_ERR(xino.file);
++		if (IS_ERR(xino.file))
++			goto out;
++
++		err = au_xino_set(sb, &xino, /*remount*/0);
++		fput(xino.file);
++		if (unlikely(err))
++			goto out;
++	}
++
++	/* restore udba */
++	sbinfo->si_mntflags &= ~AuOptMask_UDBA;
++	sbinfo->si_mntflags |= (tmp & AuOptMask_UDBA);
++	if (au_opt_test(tmp, UDBA_HINOTIFY)) {
++		struct inode *dir = sb->s_root->d_inode;
++		au_reset_hinotify(dir,
++				  au_hi_flags(dir, /*isdir*/1) & ~AuHi_XINO);
++	}
++
++ out:
++	return err;
++}
++
++int au_opts_remount(struct super_block *sb, struct au_opts *opts)
++{
++	int err, rerr;
++	struct inode *dir;
++	struct au_opt_xino *opt_xino;
++	struct au_opt *opt;
++	struct au_sbinfo *sbinfo;
++
++	dir = sb->s_root->d_inode;
++	sbinfo = au_sbi(sb);
++	err = 0;
++	opt_xino = NULL;
++	opt = opts->opt;
++	while (err >= 0 && opt->type != Opt_tail) {
++		err = au_opt_simple(sb, opt, opts);
++		if (!err)
++			err = au_opt_br(sb, opt, opts);
++		if (!err)
++			err = au_opt_xino(sb, opt, &opt_xino, opts);
++		opt++;
++	}
++	if (err > 0)
++		err = 0;
++	AuTraceErr(err);
++	/* go on even err */
++
++	rerr = au_opts_verify(sb, opts->sb_flags, /*pending*/0);
++	if (unlikely(rerr && !err))
++		err = rerr;
++
++	if (au_ftest_opts(opts->flags, TRUNC_XIB)) {
++		rerr = au_xib_trunc(sb);
++		if (unlikely(rerr && !err))
++			err = rerr;
++	}
++
++	/* will be handled by the caller */
++	if (!au_ftest_opts(opts->flags, REFRESH_DIR)
++	    && (opts->given_udba || au_opt_test(sbinfo->si_mntflags, XINO)))
++		au_fset_opts(opts->flags, REFRESH_DIR);
++
++	AuDbg("status 0x%x\n", opts->flags);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++unsigned int au_opt_udba(struct super_block *sb)
++{
++	return au_mntflags(sb) & AuOptMask_UDBA;
++}
+diff -uNr test/fs/aufs/opts.h aufs2-standalone/fs/aufs/opts.h
+--- test/fs/aufs/opts.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/opts.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,180 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * mount options/flags
++ */
++
++#ifndef __AUFS_OPTS_H__
++#define __AUFS_OPTS_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/namei.h>
++#include <linux/aufs_type.h>
++
++/* ---------------------------------------------------------------------- */
++
++/* mount flags */
++#define AuOpt_XINO		1		/* external inode number bitmap
++						   and translation table */
++#define AuOpt_TRUNC_XINO	(1 << 1)	/* truncate xino files */
++#define AuOpt_UDBA_NONE		(1 << 2)	/* users direct branch access */
++#define AuOpt_UDBA_REVAL	(1 << 3)
++#define AuOpt_UDBA_HINOTIFY	(1 << 4)
++#define AuOpt_PLINK		(1 << 5)	/* pseudo-link */
++#define AuOpt_DIRPERM1		(1 << 6)	/* unimplemented */
++#define AuOpt_REFROF		(1 << 7)	/* unimplemented */
++#define AuOpt_ALWAYS_DIROPQ	(1 << 8)	/* policy to creating diropq */
++#define AuOpt_SUM		(1 << 9)	/* summation for statfs(2) */
++#define AuOpt_SUM_W		(1 << 10)	/* unimplemented */
++#define AuOpt_WARN_PERM		(1 << 11)	/* warn when add-branch */
++#define AuOpt_VERBOSE		(1 << 12)	/* busy inode when del-branch */
++
++#ifndef CONFIG_AUFS_HINOTIFY
++#undef AuOpt_UDBA_HINOTIFY
++#define AuOpt_UDBA_HINOTIFY	0
++#endif
++
++#define AuOpt_Def	(AuOpt_XINO \
++			 | AuOpt_UDBA_REVAL \
++			 | AuOpt_PLINK \
++			 /* | AuOpt_DIRPERM1 */ \
++			 | AuOpt_WARN_PERM)
++#define AuOptMask_UDBA	(AuOpt_UDBA_NONE \
++			 | AuOpt_UDBA_REVAL \
++			 | AuOpt_UDBA_HINOTIFY)
++
++#define au_opt_test(flags, name)	(flags & AuOpt_##name)
++#define au_opt_set(flags, name) do { \
++	BUILD_BUG_ON(AuOpt_##name & AuOptMask_UDBA); \
++	((flags) |= AuOpt_##name); \
++} while (0)
++#define au_opt_set_udba(flags, name) do { \
++	(flags) &= ~AuOptMask_UDBA; \
++	((flags) |= AuOpt_##name); \
++} while (0)
++#define au_opt_clr(flags, name)		{ ((flags) &= ~AuOpt_##name); }
++
++/* ---------------------------------------------------------------------- */
++
++/* policies to select one among multiple writable branches */
++enum {
++	AuWbrCreate_TDP,	/* top down parent */
++	AuWbrCreate_RR,		/* round robin */
++	AuWbrCreate_MFS,	/* most free space */
++	AuWbrCreate_MFSV,	/* mfs with seconds */
++	AuWbrCreate_MFSRR,	/* mfs then rr */
++	AuWbrCreate_MFSRRV,	/* mfs then rr with seconds */
++	AuWbrCreate_PMFS,	/* parent and mfs */
++	AuWbrCreate_PMFSV,	/* parent and mfs with seconds */
++
++	AuWbrCreate_Def = AuWbrCreate_TDP
++};
++
++enum {
++	AuWbrCopyup_TDP,	/* top down parent */
++	AuWbrCopyup_BUP,	/* bottom up parent */
++	AuWbrCopyup_BU,		/* bottom up */
++
++	AuWbrCopyup_Def = AuWbrCopyup_TDP
++};
++
++/* ---------------------------------------------------------------------- */
++
++struct au_opt_add {
++	aufs_bindex_t	bindex;
++	char		*pathname;
++	int		perm;
++	struct path	path;
++};
++
++struct au_opt_del {
++	char		*pathname;
++	struct path	h_path;
++};
++
++struct au_opt_mod {
++	char		*path;
++	int		perm;
++	struct dentry	*h_root;
++};
++
++struct au_opt_xino {
++	char		*path;
++	struct file	*file;
++};
++
++struct au_opt_xino_itrunc {
++	aufs_bindex_t	bindex;
++};
++
++struct au_opt_wbr_create {
++	int			wbr_create;
++	int			mfs_second;
++	unsigned long long	mfsrr_watermark;
++};
++
++struct au_opt {
++	int type;
++	union {
++		struct au_opt_xino	xino;
++		struct au_opt_xino_itrunc xino_itrunc;
++		struct au_opt_add	add;
++		struct au_opt_del	del;
++		struct au_opt_mod	mod;
++		int			dirwh;
++		int			rdcache;
++		int			deblk;
++		int			nhash;
++		int			udba;
++		struct au_opt_wbr_create wbr_create;
++		int			wbr_copyup;
++	};
++};
++
++/* opts flags */
++#define AuOpts_REMOUNT		1
++#define AuOpts_REFRESH_DIR	(1 << 1)
++#define AuOpts_REFRESH_NONDIR	(1 << 2)
++#define AuOpts_TRUNC_XIB	(1 << 3)
++#define au_ftest_opts(flags, name)	((flags) & AuOpts_##name)
++#define au_fset_opts(flags, name)	{ (flags) |= AuOpts_##name; }
++#define au_fclr_opts(flags, name)	{ (flags) &= ~AuOpts_##name; }
++
++struct au_opts {
++	struct au_opt	*opt;
++	int		max_opt;
++
++	unsigned int	given_udba;
++	unsigned int	flags;
++	unsigned long	sb_flags;
++};
++
++/* ---------------------------------------------------------------------- */
++
++const char *au_optstr_br_perm(int brperm);
++const char *au_optstr_udba(int udba);
++const char *au_optstr_wbr_copyup(int wbr_copyup);
++const char *au_optstr_wbr_create(int wbr_create);
++
++void au_opts_free(struct au_opts *opts);
++int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts);
++int au_opts_verify(struct super_block *sb, unsigned long sb_flags,
++		   unsigned int pending);
++int au_opts_mount(struct super_block *sb, struct au_opts *opts);
++int au_opts_remount(struct super_block *sb, struct au_opts *opts);
++
++unsigned int au_opt_udba(struct super_block *sb);
++
++/* ---------------------------------------------------------------------- */
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_OPTS_H__ */
+diff -uNr test/fs/aufs/plink.c aufs2-standalone/fs/aufs/plink.c
+--- test/fs/aufs/plink.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/plink.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,335 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * pseudo-link
++ */
++
++#include "aufs.h"
++
++/*
++ * during a user process maintains the pseudo-links,
++ * prohibit adding a new plink and branch manipulation.
++ */
++void au_plink_block_maintain(struct super_block *sb)
++{
++	struct au_sbinfo *sbi = au_sbi(sb);
++	/* gave up wake_up_bit() */
++	wait_event(sbi->si_plink_wq, !au_ftest_si(sbi, MAINTAIN_PLINK));
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct pseudo_link {
++	struct list_head list;
++	struct inode *inode;
++};
++
++#ifdef CONFIG_AUFS_DEBUG
++void au_plink_list(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++	struct list_head *plink_list;
++	struct pseudo_link *plink;
++
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
++
++	plink_list = &sbinfo->si_plink.head;
++	spin_lock(&sbinfo->si_plink.spin);
++	list_for_each_entry(plink, plink_list, list)
++		AuDbg("%lu\n", plink->inode->i_ino);
++	spin_unlock(&sbinfo->si_plink.spin);
++}
++#endif
++
++/* is the inode pseudo-linked? */
++int au_plink_test(struct inode *inode)
++{
++	int found;
++	struct au_sbinfo *sbinfo;
++	struct list_head *plink_list;
++	struct pseudo_link *plink;
++
++	sbinfo = au_sbi(inode->i_sb);
++	AuDebugOn(!au_opt_test(au_mntflags(inode->i_sb), PLINK));
++
++	found = 0;
++	plink_list = &sbinfo->si_plink.head;
++	spin_lock(&sbinfo->si_plink.spin);
++	list_for_each_entry(plink, plink_list, list)
++		if (plink->inode == inode) {
++			found = 1;
++			break;
++		}
++	spin_unlock(&sbinfo->si_plink.spin);
++	return found;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * generate a name for plink.
++ * the file will be stored under AUFS_WH_PLINKDIR.
++ */
++/* 20 is max digits length of ulong 64 */
++#define PLINK_NAME_LEN	((20 + 1) * 2)
++
++static int plink_name(char *name, int len, struct inode *inode,
++		      aufs_bindex_t bindex)
++{
++	int rlen;
++	struct inode *h_inode;
++
++	h_inode = au_h_iptr(inode, bindex);
++	rlen = snprintf(name, len, "%lu.%lu", inode->i_ino, h_inode->i_ino);
++	return rlen;
++}
++
++/* lookup the plink-ed @inode under the branch at @bindex */
++struct dentry *au_plink_lkup(struct inode *inode, aufs_bindex_t bindex)
++{
++	struct dentry *h_dentry, *h_parent;
++	struct au_branch *br;
++	struct inode *h_dir;
++	char a[PLINK_NAME_LEN];
++	struct qstr tgtname = {
++		.name	= a
++	};
++
++	br = au_sbr(inode->i_sb, bindex);
++	h_parent = br->br_wbr->wbr_plink;
++	h_dir = h_parent->d_inode;
++	tgtname.len = plink_name(a, sizeof(a), inode, bindex);
++
++	/* always superio. */
++	mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_CHILD2);
++	h_dentry = au_sio_lkup_one(&tgtname, h_parent, br);
++	mutex_unlock(&h_dir->i_mutex);
++	return h_dentry;
++}
++
++/* create a pseudo-link */
++static int do_whplink(struct qstr *tgt, struct dentry *h_parent,
++		      struct dentry *h_dentry, struct au_branch *br)
++{
++	int err;
++	struct path h_path = {
++		.mnt = br->br_mnt
++	};
++	struct inode *h_dir;
++
++	h_dir = h_parent->d_inode;
++ again:
++	h_path.dentry = au_lkup_one(tgt, h_parent, br, /*nd*/NULL);
++	err = PTR_ERR(h_path.dentry);
++	if (IS_ERR(h_path.dentry))
++		goto out;
++
++	err = 0;
++	/* wh.plink dir is not monitored */
++	if (h_path.dentry->d_inode
++	    && h_path.dentry->d_inode != h_dentry->d_inode) {
++		err = vfsub_unlink(h_dir, &h_path, /*force*/0);
++		dput(h_path.dentry);
++		h_path.dentry = NULL;
++		if (!err)
++			goto again;
++	}
++	if (!err && !h_path.dentry->d_inode)
++		err = vfsub_link(h_dentry, h_dir, &h_path);
++	dput(h_path.dentry);
++
++ out:
++	return err;
++}
++
++struct do_whplink_args {
++	int *errp;
++	struct qstr *tgt;
++	struct dentry *h_parent;
++	struct dentry *h_dentry;
++	struct au_branch *br;
++};
++
++static void call_do_whplink(void *args)
++{
++	struct do_whplink_args *a = args;
++	*a->errp = do_whplink(a->tgt, a->h_parent, a->h_dentry, a->br);
++}
++
++static int whplink(struct dentry *h_dentry, struct inode *inode,
++		   aufs_bindex_t bindex, struct au_branch *br)
++{
++	int err, wkq_err;
++	struct au_wbr *wbr;
++	struct dentry *h_parent;
++	struct inode *h_dir;
++	char a[PLINK_NAME_LEN];
++	struct qstr tgtname = {
++		.name = a
++	};
++
++	wbr = au_sbr(inode->i_sb, bindex)->br_wbr;
++	h_parent = wbr->wbr_plink;
++	h_dir = h_parent->d_inode;
++	tgtname.len = plink_name(a, sizeof(a), inode, bindex);
++
++	/* always superio. */
++	mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_CHILD2);
++	if (!au_test_wkq(current)) {
++		struct do_whplink_args args = {
++			.errp		= &err,
++			.tgt		= &tgtname,
++			.h_parent	= h_parent,
++			.h_dentry	= h_dentry,
++			.br		= br
++		};
++		wkq_err = au_wkq_wait(call_do_whplink, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	} else
++		err = do_whplink(&tgtname, h_parent, h_dentry, br);
++	mutex_unlock(&h_dir->i_mutex);
++
++	return err;
++}
++
++/* free a single plink */
++static void do_put_plink(struct pseudo_link *plink, int do_del)
++{
++	iput(plink->inode);
++	if (do_del)
++		list_del(&plink->list);
++	kfree(plink);
++}
++
++/*
++ * create a new pseudo-link for @h_dentry on @bindex.
++ * the linked inode is held in aufs @inode.
++ */
++void au_plink_append(struct inode *inode, aufs_bindex_t bindex,
++		     struct dentry *h_dentry)
++{
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++	struct list_head *plink_list;
++	struct pseudo_link *plink;
++	int found, err, cnt;
++
++	sb = inode->i_sb;
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
++
++	err = 0;
++	cnt = 0;
++	found = 0;
++	plink_list = &sbinfo->si_plink.head;
++	spin_lock(&sbinfo->si_plink.spin);
++	list_for_each_entry(plink, plink_list, list) {
++		cnt++;
++		if (plink->inode == inode) {
++			found = 1;
++			break;
++		}
++	}
++	if (found) {
++		spin_unlock(&sbinfo->si_plink.spin);
++		return;
++	}
++
++	plink = NULL;
++	if (!found) {
++		plink = kmalloc(sizeof(*plink), GFP_ATOMIC);
++		if (plink) {
++			plink->inode = au_igrab(inode);
++			list_add(&plink->list, plink_list);
++			cnt++;
++		} else
++			err = -ENOMEM;
++	}
++	spin_unlock(&sbinfo->si_plink.spin);
++
++	if (!err) {
++		au_plink_block_maintain(sb);
++		err = whplink(h_dentry, inode, bindex, au_sbr(sb, bindex));
++	}
++
++	if (unlikely(cnt > AUFS_PLINK_WARN))
++		AuWarn1("unexpectedly many pseudo links, %d\n", cnt);
++	if (unlikely(err)) {
++		AuWarn("err %d, damaged pseudo link.\n", err);
++		if (!found && plink)
++			do_put_plink(plink, /*do_del*/1);
++	}
++}
++
++/* free all plinks */
++void au_plink_put(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++	struct list_head *plink_list;
++	struct pseudo_link *plink, *tmp;
++
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
++
++	plink_list = &sbinfo->si_plink.head;
++	/* no spin_lock since sbinfo is write-locked */
++	list_for_each_entry_safe(plink, tmp, plink_list, list)
++		do_put_plink(plink, 0);
++	INIT_LIST_HEAD(plink_list);
++}
++
++/* free the plinks on a branch specified by @br_id */
++void au_plink_half_refresh(struct super_block *sb, aufs_bindex_t br_id)
++{
++	struct au_sbinfo *sbinfo;
++	struct list_head *plink_list;
++	struct pseudo_link *plink, *tmp;
++	struct inode *inode;
++	aufs_bindex_t bstart, bend, bindex;
++	unsigned char do_put;
++
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
++
++	plink_list = &sbinfo->si_plink.head;
++	/* no spin_lock since sbinfo is write-locked */
++	list_for_each_entry_safe(plink, tmp, plink_list, list) {
++		do_put = 0;
++		inode = au_igrab(plink->inode);
++		ii_write_lock_child(inode);
++		bstart = au_ibstart(inode);
++		bend = au_ibend(inode);
++		if (bstart >= 0) {
++			for (bindex = bstart; bindex <= bend; bindex++) {
++				if (!au_h_iptr(inode, bindex)
++				    || au_ii_br_id(inode, bindex) != br_id)
++					continue;
++				au_set_h_iptr(inode, bindex, NULL, 0);
++				do_put = 1;
++				break;
++			}
++		} else
++			do_put_plink(plink, 1);
++
++		if (do_put) {
++			for (bindex = bstart; bindex <= bend; bindex++)
++				if (au_h_iptr(inode, bindex)) {
++					do_put = 0;
++					break;
++				}
++			if (do_put)
++				do_put_plink(plink, 1);
++		}
++		ii_write_unlock(inode);
++		iput(inode);
++	}
++}
+diff -uNr test/fs/aufs/rwsem.h aufs2-standalone/fs/aufs/rwsem.h
+--- test/fs/aufs/rwsem.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/rwsem.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,52 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * simple read-write semaphore wrappers
++ */
++
++#ifndef __AUFS_RWSEM_H__
++#define __AUFS_RWSEM_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++
++#define au_rwsem_destroy(rw)	AuDebugOn(rwsem_is_locked(rw))
++#define AuRwMustNoWaiters(rw)	AuDebugOn(!list_empty(&(rw)->wait_list))
++
++#define AuSimpleLockRwsemFuncs(prefix, param, rwsem) \
++static inline void prefix##_read_lock(param) \
++{ down_read(rwsem); } \
++static inline void prefix##_write_lock(param) \
++{ down_write(rwsem); } \
++static inline int prefix##_read_trylock(param) \
++{ return down_read_trylock(rwsem); } \
++static inline int prefix##_write_trylock(param) \
++{ return down_write_trylock(rwsem); }
++/* why is not _nested version defined */
++/* static inline void prefix##_read_trylock_nested(param, lsc)
++{ down_write_trylock_nested(rwsem, lsc)); }
++static inline void prefix##_write_trylock_nestd(param, lsc)
++{ down_write_trylock_nested(rwsem, lsc); } */
++
++#define AuSimpleUnlockRwsemFuncs(prefix, param, rwsem) \
++static inline void prefix##_read_unlock(param) \
++{ up_read(rwsem); } \
++static inline void prefix##_write_unlock(param) \
++{ up_write(rwsem); } \
++static inline void prefix##_downgrade_lock(param) \
++{ downgrade_write(rwsem); }
++
++#define AuSimpleRwsemFuncs(prefix, param, rwsem) \
++	AuSimpleLockRwsemFuncs(prefix, param, rwsem) \
++	AuSimpleUnlockRwsemFuncs(prefix, param, rwsem)
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_RWSEM_H__ */
+diff -uNr test/fs/aufs/sbinfo.c aufs2-standalone/fs/aufs/sbinfo.c
+--- test/fs/aufs/sbinfo.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/sbinfo.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,192 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * superblock private data
++ */
++
++#include "aufs.h"
++
++/*
++ * they are necessary regardless sysfs is disabled.
++ */
++void au_si_free(struct kobject *kobj)
++{
++	struct au_sbinfo *sbinfo;
++	struct super_block *sb;
++
++	sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
++	AuDebugOn(!list_empty(&sbinfo->si_plink.head));
++
++	sb = sbinfo->si_sb;
++	si_write_lock(sb);
++	au_xino_clr(sb);
++	au_br_free(sbinfo);
++	kfree(sbinfo->si_branch);
++	mutex_destroy(&sbinfo->si_xib_mtx);
++	si_write_unlock(sb);
++	au_rwsem_destroy(&sbinfo->si_rwsem);
++
++	kfree(sbinfo);
++}
++
++int au_si_alloc(struct super_block *sb)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++
++	err = -ENOMEM;
++	sbinfo = kmalloc(sizeof(*sbinfo), GFP_NOFS);
++	if (unlikely(!sbinfo))
++		goto out;
++
++	/* will be reallocated separately */
++	sbinfo->si_branch = kzalloc(sizeof(*sbinfo->si_branch), GFP_NOFS);
++	if (unlikely(!sbinfo->si_branch))
++		goto out_sbinfo;
++
++	memset(&sbinfo->si_kobj, 0, sizeof(sbinfo->si_kobj));
++	err = sysaufs_si_init(sbinfo);
++	if (unlikely(err))
++		goto out_br;
++
++	au_nwt_init(&sbinfo->si_nowait);
++	init_rwsem(&sbinfo->si_rwsem);
++	down_write(&sbinfo->si_rwsem);
++	sbinfo->si_generation = 0;
++	sbinfo->au_si_status = 0;
++	sbinfo->si_bend = -1;
++	sbinfo->si_last_br_id = 0;
++
++	sbinfo->si_wbr_copyup = AuWbrCopyup_Def;
++	sbinfo->si_wbr_create = AuWbrCreate_Def;
++	sbinfo->si_wbr_copyup_ops = au_wbr_copyup_ops + AuWbrCopyup_Def;
++	sbinfo->si_wbr_create_ops = au_wbr_create_ops + AuWbrCreate_Def;
++
++	sbinfo->si_mntflags = AuOpt_Def;
++
++	sbinfo->si_xread = NULL;
++	sbinfo->si_xwrite = NULL;
++	sbinfo->si_xib = NULL;
++	mutex_init(&sbinfo->si_xib_mtx);
++	sbinfo->si_xib_buf = NULL;
++	sbinfo->si_xino_brid = -1;
++	/* leave si_xib_last_pindex and si_xib_next_bit */
++
++	sbinfo->si_rdcache = AUFS_RDCACHE_DEF * HZ;
++	sbinfo->si_dirwh = AUFS_DIRWH_DEF;
++
++	au_spl_init(&sbinfo->si_plink);
++	init_waitqueue_head(&sbinfo->si_plink_wq);
++
++	/* leave other members for sysaufs and si_mnt. */
++	sbinfo->si_sb = sb;
++	sb->s_fs_info = sbinfo;
++	au_debug_sbinfo_init(sbinfo);
++	return 0; /* success */
++
++ out_br:
++	kfree(sbinfo->si_branch);
++ out_sbinfo:
++	kfree(sbinfo);
++ out:
++	return err;
++}
++
++int au_sbr_realloc(struct au_sbinfo *sbinfo, int nbr)
++{
++	int err, sz;
++	struct au_branch **brp;
++
++	err = -ENOMEM;
++	sz = sizeof(*brp) * (sbinfo->si_bend + 1);
++	if (unlikely(!sz))
++		sz = sizeof(*brp);
++	brp = au_kzrealloc(sbinfo->si_branch, sz, sizeof(*brp) * nbr, GFP_NOFS);
++	if (brp) {
++		sbinfo->si_branch = brp;
++		err = 0;
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++unsigned int au_sigen_inc(struct super_block *sb)
++{
++	unsigned int gen;
++
++	gen = ++au_sbi(sb)->si_generation;
++	au_update_digen(sb->s_root);
++	au_update_iigen(sb->s_root->d_inode);
++	sb->s_root->d_inode->i_version++;
++	return gen;
++}
++
++aufs_bindex_t au_new_br_id(struct super_block *sb)
++{
++	aufs_bindex_t br_id;
++	int i;
++	struct au_sbinfo *sbinfo;
++
++	sbinfo = au_sbi(sb);
++	for (i = 0; i <= AUFS_BRANCH_MAX; i++) {
++		br_id = ++sbinfo->si_last_br_id;
++		if (br_id && au_br_index(sb, br_id) < 0)
++			return br_id;
++	}
++
++	return -1;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* dentry and super_block lock. call at entry point */
++void aufs_read_lock(struct dentry *dentry, int flags)
++{
++	si_read_lock(dentry->d_sb, flags);
++	if (au_ftest_lock(flags, DW))
++		di_write_lock_child(dentry);
++	else
++		di_read_lock_child(dentry, flags);
++}
++
++void aufs_read_unlock(struct dentry *dentry, int flags)
++{
++	if (au_ftest_lock(flags, DW))
++		di_write_unlock(dentry);
++	else
++		di_read_unlock(dentry, flags);
++	si_read_unlock(dentry->d_sb);
++}
++
++void aufs_write_lock(struct dentry *dentry)
++{
++	si_write_lock(dentry->d_sb);
++	di_write_lock_child(dentry);
++}
++
++void aufs_write_unlock(struct dentry *dentry)
++{
++	di_write_unlock(dentry);
++	si_write_unlock(dentry->d_sb);
++}
++
++void aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int flags)
++{
++	si_read_lock(d1->d_sb, flags);
++	di_write_lock2_child(d1, d2, au_ftest_lock(flags, DIR));
++}
++
++void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2)
++{
++	di_write_unlock2(d1, d2);
++	si_read_unlock(d1->d_sb);
++}
+diff -uNr test/fs/aufs/spl.h aufs2-standalone/fs/aufs/spl.h
+--- test/fs/aufs/spl.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/spl.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,47 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * simple list protected by a spinlock
++ */
++
++#ifndef __AUFS_SPL_H__
++#define __AUFS_SPL_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++
++struct au_splhead {
++	spinlock_t		spin;
++	struct list_head	head;
++};
++
++static inline void au_spl_init(struct au_splhead *spl)
++{
++	spin_lock_init(&spl->spin);
++	INIT_LIST_HEAD(&spl->head);
++}
++
++static inline void au_spl_add(struct list_head *list, struct au_splhead *spl)
++{
++	spin_lock(&spl->spin);
++	list_add(list, &spl->head);
++	spin_unlock(&spl->spin);
++}
++
++static inline void au_spl_del(struct list_head *list, struct au_splhead *spl)
++{
++	spin_lock(&spl->spin);
++	list_del(list);
++	spin_unlock(&spl->spin);
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_SPL_H__ */
+diff -uNr test/fs/aufs/super.c aufs2-standalone/fs/aufs/super.c
+--- test/fs/aufs/super.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/super.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,846 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * mount and super_block operations
++ */
++
++#include <linux/buffer_head.h>
++#include <linux/seq_file.h>
++#include <linux/statfs.h>
++#include "aufs.h"
++
++/*
++ * super_operations
++ */
++static struct inode *aufs_alloc_inode(struct super_block *sb __maybe_unused)
++{
++	struct au_icntnr *c;
++
++	c = au_cache_alloc_icntnr();
++	if (c) {
++		inode_init_once(&c->vfs_inode);
++		c->vfs_inode.i_version = 1; /* sigen(sb); */
++		c->iinfo.ii_hinode = NULL;
++		return &c->vfs_inode;
++	}
++	return NULL;
++}
++
++static void aufs_destroy_inode(struct inode *inode)
++{
++	au_iinfo_fin(inode);
++	au_cache_free_icntnr(container_of(inode, struct au_icntnr, vfs_inode));
++}
++
++struct inode *au_iget_locked(struct super_block *sb, ino_t ino)
++{
++	struct inode *inode;
++	int err;
++
++	inode = iget_locked(sb, ino);
++	if (unlikely(!inode)) {
++		inode = ERR_PTR(-ENOMEM);
++		goto out;
++	}
++	if (!(inode->i_state & I_NEW))
++		goto out;
++
++	err = au_iinfo_init(inode);
++	if (!err)
++		inode->i_version++;
++	else {
++		iget_failed(inode);
++		inode = ERR_PTR(err);
++	}
++
++ out:
++	/* never return NULL */
++	AuDebugOn(!inode);
++	AuTraceErrPtr(inode);
++	return inode;
++}
++
++/* lock free root dinfo */
++static int au_show_brs(struct seq_file *seq, struct super_block *sb)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	struct path path;
++	struct au_hdentry *hd;
++	struct au_branch *br;
++
++	err = 0;
++	bend = au_sbend(sb);
++	hd = au_di(sb->s_root)->di_hdentry;
++	for (bindex = 0; !err && bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		path.mnt = br->br_mnt;
++		path.dentry = hd[bindex].hd_dentry;
++		err = au_seq_path(seq, &path);
++		if (err > 0)
++			err = seq_printf(seq, "=%s",
++					 au_optstr_br_perm(br->br_perm));
++		if (!err && bindex != bend)
++			err = seq_putc(seq, ':');
++	}
++
++	return err;
++}
++
++static void au_show_wbr_create(struct seq_file *m, int v,
++			       struct au_sbinfo *sbinfo)
++{
++	const char *pat;
++
++	seq_printf(m, ",create=");
++	pat = au_optstr_wbr_create(v);
++	switch (v) {
++	case AuWbrCreate_TDP:
++	case AuWbrCreate_RR:
++	case AuWbrCreate_MFS:
++	case AuWbrCreate_PMFS:
++		seq_printf(m, pat);
++		break;
++	case AuWbrCreate_MFSV:
++		seq_printf(m, /*pat*/"mfs:%lu",
++			   sbinfo->si_wbr_mfs.mfs_expire / HZ);
++		break;
++	case AuWbrCreate_PMFSV:
++		seq_printf(m, /*pat*/"pmfs:%lu",
++			   sbinfo->si_wbr_mfs.mfs_expire / HZ);
++		break;
++	case AuWbrCreate_MFSRR:
++		seq_printf(m, /*pat*/"mfsrr:%llu",
++			   sbinfo->si_wbr_mfs.mfsrr_watermark);
++		break;
++	case AuWbrCreate_MFSRRV:
++		seq_printf(m, /*pat*/"mfsrr:%llu:%lu",
++			   sbinfo->si_wbr_mfs.mfsrr_watermark,
++			   sbinfo->si_wbr_mfs.mfs_expire / HZ);
++		break;
++	}
++}
++
++static int au_show_xino(struct seq_file *seq, struct vfsmount *mnt)
++{
++	int err;
++	const int len = sizeof(AUFS_XINO_FNAME) - 1;
++	aufs_bindex_t bindex, brid;
++	struct super_block *sb;
++	struct qstr *name;
++	struct file *f;
++	struct dentry *d, *h_root;
++
++	err = 0;
++	sb = mnt->mnt_sb;
++	f = au_sbi(sb)->si_xib;
++	if (!f)
++		goto out;
++
++	/* stop printing the default xino path on the first writable branch */
++	h_root = NULL;
++	brid = au_xino_brid(sb);
++	if (brid >= 0) {
++		bindex = au_br_index(sb, brid);
++		h_root = au_di(sb->s_root)->di_hdentry[0 + bindex].hd_dentry;
++	}
++	d = f->f_dentry;
++	name = &d->d_name;
++	/* safe ->d_parent because the file is unlinked */
++	if (d->d_parent == h_root
++	    && name->len == len
++	    && !memcmp(name->name, AUFS_XINO_FNAME, len))
++		goto out;
++
++	seq_puts(seq, ",xino=");
++	err = au_xino_path(seq, f);
++
++ out:
++	return err;
++}
++
++/* seq_file will re-call me in case of too long string */
++static int aufs_show_options(struct seq_file *m, struct vfsmount *mnt)
++{
++	int err, n;
++	unsigned int mnt_flags, v;
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++
++#define AuBool(name, str) do { \
++	v = au_opt_test(mnt_flags, name); \
++	if (v != au_opt_test(AuOpt_Def, name)) \
++		seq_printf(m, ",%s" #str, v ? "" : "no"); \
++} while (0)
++
++#define AuStr(name, str) do { \
++	v = mnt_flags & AuOptMask_##name; \
++	if (v != (AuOpt_Def & AuOptMask_##name)) \
++		seq_printf(m, "," #str "=%s", au_optstr_##str(v)); \
++} while (0)
++
++	/* lock free root dinfo */
++	sb = mnt->mnt_sb;
++	si_noflush_read_lock(sb);
++	sbinfo = au_sbi(sb);
++	seq_printf(m, ",si=%lx", sysaufs_si_id(sbinfo));
++
++	mnt_flags = au_mntflags(sb);
++	if (au_opt_test(mnt_flags, XINO)) {
++		err = au_show_xino(m, mnt);
++		if (unlikely(err))
++			goto out;
++	} else
++		seq_puts(m, ",noxino");
++
++	AuBool(TRUNC_XINO, trunc_xino);
++	AuStr(UDBA, udba);
++	AuBool(PLINK, plink);
++	/* AuBool(DIRPERM1, dirperm1); */
++	/* AuBool(REFROF, refrof); */
++
++	v = sbinfo->si_wbr_create;
++	if (v != AuWbrCreate_Def)
++		au_show_wbr_create(m, v, sbinfo);
++
++	v = sbinfo->si_wbr_copyup;
++	if (v != AuWbrCopyup_Def)
++		seq_printf(m, ",cpup=%s", au_optstr_wbr_copyup(v));
++
++	v = au_opt_test(mnt_flags, ALWAYS_DIROPQ);
++	if (v != au_opt_test(AuOpt_Def, ALWAYS_DIROPQ))
++		seq_printf(m, ",diropq=%c", v ? 'a' : 'w');
++
++	n = sbinfo->si_dirwh;
++	if (n != AUFS_DIRWH_DEF)
++		seq_printf(m, ",dirwh=%d", n);
++
++	n = sbinfo->si_rdcache / HZ;
++	if (n != AUFS_RDCACHE_DEF)
++		seq_printf(m, ",rdcache=%d", n);
++
++	AuBool(SUM, sum);
++	/* AuBool(SUM_W, wsum); */
++	AuBool(WARN_PERM, warn_perm);
++	AuBool(VERBOSE, verbose);
++
++ out:
++	/* be sure to print "br:" last */
++	if (!sysaufs_brs) {
++		seq_puts(m, ",br:");
++		au_show_brs(m, sb);
++	}
++	si_read_unlock(sb);
++	return 0;
++
++#undef Deleted
++#undef AuBool
++#undef AuStr
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* sum mode which returns the summation for statfs(2) */
++
++static u64 au_add_till_max(u64 a, u64 b)
++{
++	u64 old;
++
++	old = a;
++	a += b;
++	if (old < a)
++		return a;
++	return ULLONG_MAX;
++}
++
++static int au_statfs_sum(struct super_block *sb, struct kstatfs *buf)
++{
++	int err;
++	u64 blocks, bfree, bavail, files, ffree;
++	aufs_bindex_t bend, bindex, i;
++	unsigned char shared;
++	struct vfsmount *h_mnt;
++	struct super_block *h_sb;
++
++	blocks = 0;
++	bfree = 0;
++	bavail = 0;
++	files = 0;
++	ffree = 0;
++
++	err = 0;
++	bend = au_sbend(sb);
++	for (bindex = bend; bindex >= 0; bindex--) {
++		h_mnt = au_sbr_mnt(sb, bindex);
++		h_sb = h_mnt->mnt_sb;
++		shared = 0;
++		for (i = bindex + 1; !shared && i <= bend; i++)
++			shared = (au_sbr_sb(sb, i) == h_sb);
++		if (shared)
++			continue;
++
++		/* sb->s_root for NFS is unreliable */
++		err = vfs_statfs(h_mnt->mnt_root, buf);
++		if (unlikely(err))
++			goto out;
++
++		blocks = au_add_till_max(blocks, buf->f_blocks);
++		bfree = au_add_till_max(bfree, buf->f_bfree);
++		bavail = au_add_till_max(bavail, buf->f_bavail);
++		files = au_add_till_max(files, buf->f_files);
++		ffree = au_add_till_max(ffree, buf->f_ffree);
++	}
++
++	buf->f_blocks = blocks;
++	buf->f_bfree = bfree;
++	buf->f_bavail = bavail;
++	buf->f_files = files;
++	buf->f_ffree = ffree;
++
++ out:
++	return err;
++}
++
++static int aufs_statfs(struct dentry *dentry, struct kstatfs *buf)
++{
++	int err;
++	struct super_block *sb;
++
++	/* lock free root dinfo */
++	sb = dentry->d_sb;
++	si_noflush_read_lock(sb);
++	if (!au_opt_test(au_mntflags(sb), SUM))
++		/* sb->s_root for NFS is unreliable */
++		err = vfs_statfs(au_sbr_mnt(sb, 0)->mnt_root, buf);
++	else
++		err = au_statfs_sum(sb, buf);
++	si_read_unlock(sb);
++
++	if (!err) {
++		buf->f_type = AUFS_SUPER_MAGIC;
++		buf->f_namelen -= AUFS_WH_PFX_LEN;
++		memset(&buf->f_fsid, 0, sizeof(buf->f_fsid));
++	}
++	/* buf->f_bsize = buf->f_blocks = buf->f_bfree = buf->f_bavail = -1; */
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* try flushing the lower fs at aufs remount/unmount time */
++
++static void au_fsync_br(struct super_block *sb)
++{
++	aufs_bindex_t bend, bindex;
++	int brperm;
++	struct au_branch *br;
++	struct super_block *h_sb;
++
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex < bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		brperm = br->br_perm;
++		if (brperm == AuBrPerm_RR || brperm == AuBrPerm_RRWH)
++			continue;
++		h_sb = br->br_mnt->mnt_sb;
++		if (bdev_read_only(h_sb->s_bdev))
++			continue;
++
++		lockdep_off();
++		down_write(&h_sb->s_umount);
++		shrink_dcache_sb(h_sb);
++		fsync_super(h_sb);
++		up_write(&h_sb->s_umount);
++		lockdep_on();
++	}
++}
++
++/*
++ * this IS NOT for super_operations.
++ * I guess it will be reverted someday.
++ */
++static void aufs_umount_begin(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++
++	sbinfo = au_sbi(sb);
++	if (!sbinfo)
++		return;
++
++	si_write_lock(sb);
++	au_fsync_br(sb);
++	if (au_opt_test(au_mntflags(sb), PLINK))
++		au_plink_put(sb);
++	if (sbinfo->si_wbr_create_ops->fin)
++		sbinfo->si_wbr_create_ops->fin(sb);
++	si_write_unlock(sb);
++}
++
++/* final actions when unmounting a file system */
++static void aufs_put_super(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++
++	sbinfo = au_sbi(sb);
++	if (!sbinfo)
++		return;
++
++	aufs_umount_begin(sb);
++	kobject_put(&sbinfo->si_kobj);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * refresh dentry and inode at remount time.
++ */
++static int do_refresh(struct dentry *dentry, mode_t type,
++		      unsigned int dir_flags)
++{
++	int err;
++	struct dentry *parent;
++
++	di_write_lock_child(dentry);
++	parent = dget_parent(dentry);
++	di_read_lock_parent(parent, AuLock_IR);
++
++	/* returns the number of positive dentries */
++	err = au_refresh_hdentry(dentry, type);
++	if (err >= 0) {
++		struct inode *inode = dentry->d_inode;
++		err = au_refresh_hinode(inode, dentry);
++		if (!err && type == S_IFDIR)
++			au_reset_hinotify(inode, dir_flags);
++	}
++	if (unlikely(err))
++		AuErr("unrecoverable error %d, %.*s\n", err, AuDLNPair(dentry));
++
++	di_read_unlock(parent, AuLock_IR);
++	dput(parent);
++	di_write_unlock(dentry);
++
++	return err;
++}
++
++static int test_dir(struct dentry *dentry, void *arg __maybe_unused)
++{
++	return S_ISDIR(dentry->d_inode->i_mode);
++}
++
++/* gave up consolidating with refresh_nondir() */
++static int refresh_dir(struct dentry *root, unsigned int sigen)
++{
++	int err, i, j, ndentry, e;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry **dentries;
++	struct inode *inode;
++	const unsigned int flags = au_hi_flags(root->d_inode, /*isdir*/1);
++
++	err = 0;
++	list_for_each_entry(inode, &root->d_sb->s_inodes, i_sb_list)
++		if (S_ISDIR(inode->i_mode) && au_iigen(inode) != sigen) {
++			ii_write_lock_child(inode);
++			e = au_refresh_hinode_self(inode, /*do_attr*/1);
++			ii_write_unlock(inode);
++			if (unlikely(e)) {
++				AuDbg("e %d, i%lu\n", e, inode->i_ino);
++				if (!err)
++					err = e;
++				/* go on even if err */
++			}
++		}
++
++	e = au_dpages_init(&dpages, GFP_NOFS);
++	if (unlikely(e)) {
++		if (!err)
++			err = e;
++		goto out;
++	}
++	e = au_dcsub_pages(&dpages, root, test_dir, NULL);
++	if (unlikely(e)) {
++		if (!err)
++			err = e;
++		goto out_dpages;
++	}
++
++	for (i = 0; !e && i < dpages.ndpage; i++) {
++		dpage = dpages.dpages + i;
++		dentries = dpage->dentries;
++		ndentry = dpage->ndentry;
++		for (j = 0; !e && j < ndentry; j++) {
++			struct dentry *d;
++
++			d = dentries[j];
++			au_dbg_verify_dir_parent(d, sigen);
++			if (au_digen(d) != sigen) {
++				e = do_refresh(d, S_IFDIR, flags);
++				if (unlikely(e && !err))
++					err = e;
++				/* break on err */
++			}
++		}
++	}
++
++ out_dpages:
++	au_dpages_free(&dpages);
++ out:
++	return err;
++}
++
++static int test_nondir(struct dentry *dentry, void *arg __maybe_unused)
++{
++	return !S_ISDIR(dentry->d_inode->i_mode);
++}
++
++static int refresh_nondir(struct dentry *root, unsigned int sigen,
++			  int do_dentry)
++{
++	int err, i, j, ndentry, e;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry **dentries;
++	struct inode *inode;
++
++	err = 0;
++	list_for_each_entry(inode, &root->d_sb->s_inodes, i_sb_list)
++		if (!S_ISDIR(inode->i_mode) && au_iigen(inode) != sigen) {
++			ii_write_lock_child(inode);
++			e = au_refresh_hinode_self(inode, /*do_attr*/1);
++			ii_write_unlock(inode);
++			if (unlikely(e)) {
++				AuDbg("e %d, i%lu\n", e, inode->i_ino);
++				if (!err)
++					err = e;
++				/* go on even if err */
++			}
++		}
++
++	if (!do_dentry)
++		goto out;
++
++	e = au_dpages_init(&dpages, GFP_NOFS);
++	if (unlikely(e)) {
++		if (!err)
++			err = e;
++		goto out;
++	}
++	e = au_dcsub_pages(&dpages, root, test_nondir, NULL);
++	if (unlikely(e)) {
++		if (!err)
++			err = e;
++		goto out_dpages;
++	}
++
++	for (i = 0; i < dpages.ndpage; i++) {
++		dpage = dpages.dpages + i;
++		dentries = dpage->dentries;
++		ndentry = dpage->ndentry;
++		for (j = 0; j < ndentry; j++) {
++			struct dentry *d;
++
++			d = dentries[j];
++			au_dbg_verify_nondir_parent(d, sigen);
++			inode = d->d_inode;
++			if (inode && au_digen(d) != sigen) {
++				e = do_refresh(d, inode->i_mode & S_IFMT,
++					       /*dir_flags*/0);
++				if (unlikely(e && !err))
++					err = e;
++				/* go on even err */
++			}
++		}
++	}
++
++ out_dpages:
++	au_dpages_free(&dpages);
++ out:
++	return err;
++}
++
++static void au_remount_refresh(struct super_block *sb, unsigned int flags)
++{
++	int err;
++	unsigned int sigen;
++	struct au_sbinfo *sbinfo;
++	struct dentry *root;
++	struct inode *inode;
++
++	au_sigen_inc(sb);
++	sigen = au_sigen(sb);
++	sbinfo = au_sbi(sb);
++	au_fclr_si(sbinfo, FAILED_REFRESH_DIRS);
++
++	root = sb->s_root;
++	DiMustNoWaiters(root);
++	inode = root->d_inode;
++	IiMustNoWaiters(inode);
++	au_reset_hinotify(inode, au_hi_flags(inode, /*isdir*/1));
++	di_write_unlock(root);
++
++	err = refresh_dir(root, sigen);
++	if (unlikely(err)) {
++		au_fset_si(sbinfo, FAILED_REFRESH_DIRS);
++		AuWarn("Refreshing directories failed, ignored (%d)\n", err);
++	}
++
++	if (au_ftest_opts(flags, REFRESH_NONDIR)) {
++		err = refresh_nondir(root, sigen, !err);
++		if (unlikely(err))
++			AuWarn("Refreshing non-directories failed, ignored"
++			       "(%d)\n", err);
++	}
++
++	/* aufs_write_lock() calls ..._child() */
++	di_write_lock_child(root);
++	au_cpup_attr_all(root->d_inode, /*force*/1);
++}
++
++/* stop extra interpretation of errno in mount(8), and strange error messages */
++static int cvt_err(int err)
++{
++	AuTraceErr(err);
++
++	switch (err) {
++	case -ENOENT:
++	case -ENOTDIR:
++	case -EEXIST:
++	case -EIO:
++		err = -EINVAL;
++	}
++	return err;
++}
++
++static int aufs_remount_fs(struct super_block *sb, int *flags, char *data)
++{
++	int err;
++	struct au_opts opts;
++	struct dentry *root;
++	struct inode *inode;
++	struct au_sbinfo *sbinfo;
++
++	err = 0;
++	root = sb->s_root;
++	if (!data || !*data) {
++		aufs_write_lock(root);
++		err = au_opts_verify(sb, *flags, /*pending*/0);
++		if (!err)
++			au_fsync_br(sb);
++		aufs_write_unlock(root);
++		goto out;
++	}
++
++	err = -ENOMEM;
++	memset(&opts, 0, sizeof(opts));
++	opts.opt = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!opts.opt))
++		goto out;
++	opts.max_opt = PAGE_SIZE / sizeof(*opts.opt);
++	opts.flags = AuOpts_REMOUNT;
++	opts.sb_flags = *flags;
++
++	/* parse it before aufs lock */
++	err = au_opts_parse(sb, data, &opts);
++	if (unlikely(err))
++		goto out_opts;
++
++	sbinfo = au_sbi(sb);
++	inode = root->d_inode;
++	mutex_lock(&inode->i_mutex);
++	aufs_write_lock(root);
++	au_fsync_br(sb);
++
++	/* au_opts_remount() may return an error */
++	err = au_opts_remount(sb, &opts);
++	au_opts_free(&opts);
++
++	if (au_ftest_opts(opts.flags, REFRESH_DIR)
++	    || au_ftest_opts(opts.flags, REFRESH_NONDIR))
++		au_remount_refresh(sb, opts.flags);
++
++	aufs_write_unlock(root);
++	mutex_unlock(&inode->i_mutex);
++
++ out_opts:
++	free_page((unsigned long)opts.opt);
++ out:
++	err = cvt_err(err);
++	AuTraceErr(err);
++	return err;
++}
++
++static struct super_operations aufs_sop = {
++	.alloc_inode	= aufs_alloc_inode,
++	.destroy_inode	= aufs_destroy_inode,
++	.drop_inode	= generic_delete_inode,
++	.show_options	= aufs_show_options,
++	.statfs		= aufs_statfs,
++	.put_super	= aufs_put_super,
++	.remount_fs	= aufs_remount_fs
++};
++
++/* ---------------------------------------------------------------------- */
++
++static int alloc_root(struct super_block *sb)
++{
++	int err;
++	struct inode *inode;
++	struct dentry *root;
++
++	err = -ENOMEM;
++	inode = au_iget_locked(sb, AUFS_ROOT_INO);
++	err = PTR_ERR(inode);
++	if (IS_ERR(inode))
++		goto out;
++
++	inode->i_op = &aufs_dir_iop;
++	inode->i_fop = &aufs_dir_fop;
++	inode->i_mode = S_IFDIR;
++	inode->i_nlink = 2;
++	unlock_new_inode(inode);
++
++	root = d_alloc_root(inode);
++	if (unlikely(!root))
++		goto out_iput;
++	err = PTR_ERR(root);
++	if (IS_ERR(root))
++		goto out_iput;
++
++	err = au_alloc_dinfo(root);
++	if (!err) {
++		sb->s_root = root;
++		return 0; /* success */
++	}
++	dput(root);
++	goto out; /* do not iput */
++
++ out_iput:
++	iget_failed(inode);
++	iput(inode);
++ out:
++	return err;
++
++}
++
++static int aufs_fill_super(struct super_block *sb, void *raw_data,
++			   int silent __maybe_unused)
++{
++	int err;
++	struct au_opts opts;
++	struct dentry *root;
++	struct inode *inode;
++	char *arg = raw_data;
++
++	if (unlikely(!arg || !*arg)) {
++		err = -EINVAL;
++		AuErr("no arg\n");
++		goto out;
++	}
++
++	err = -ENOMEM;
++	memset(&opts, 0, sizeof(opts));
++	opts.opt = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!opts.opt))
++		goto out;
++	opts.max_opt = PAGE_SIZE / sizeof(*opts.opt);
++	opts.sb_flags = sb->s_flags;
++
++	err = au_si_alloc(sb);
++	if (unlikely(err))
++		goto out_opts;
++
++	/* all timestamps always follow the ones on the branch */
++	sb->s_flags |= MS_NOATIME | MS_NODIRATIME;
++	sb->s_op = &aufs_sop;
++	sb->s_magic = AUFS_SUPER_MAGIC;
++	sb->s_maxbytes = 0;
++
++	err = alloc_root(sb);
++	if (unlikely(err)) {
++		si_write_unlock(sb);
++		goto out_info;
++	}
++	root = sb->s_root;
++	inode = root->d_inode;
++
++	/*
++	 * actually we can parse options regardless aufs lock here.
++	 * but at remount time, parsing must be done before aufs lock.
++	 * so we follow the same rule.
++	 */
++	ii_write_lock_parent(inode);
++	aufs_write_unlock(root);
++	err = au_opts_parse(sb, arg, &opts);
++	if (unlikely(err))
++		goto out_root;
++
++	/* lock vfs_inode first, then aufs. */
++	mutex_lock(&inode->i_mutex);
++	inode->i_op = &aufs_dir_iop;
++	inode->i_fop = &aufs_dir_fop;
++	aufs_write_lock(root);
++	err = au_opts_mount(sb, &opts);
++	au_opts_free(&opts);
++	if (unlikely(err))
++		goto out_unlock;
++	aufs_write_unlock(root);
++	mutex_unlock(&inode->i_mutex);
++	goto out_opts; /* success */
++
++ out_unlock:
++	aufs_write_unlock(root);
++	mutex_unlock(&inode->i_mutex);
++ out_root:
++	dput(root);
++	sb->s_root = NULL;
++ out_info:
++	kobject_put(&au_sbi(sb)->si_kobj);
++	sb->s_fs_info = NULL;
++ out_opts:
++	free_page((unsigned long)opts.opt);
++ out:
++	AuTraceErr(err);
++	err = cvt_err(err);
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int aufs_get_sb(struct file_system_type *fs_type, int flags,
++		       const char *dev_name __maybe_unused, void *raw_data,
++		       struct vfsmount *mnt)
++{
++	int err;
++	struct super_block *sb;
++
++	/* all timestamps always follow the ones on the branch */
++	/* mnt->mnt_flags |= MNT_NOATIME | MNT_NODIRATIME; */
++	err = get_sb_nodev(fs_type, flags, raw_data, aufs_fill_super, mnt);
++	if (!err) {
++		sb = mnt->mnt_sb;
++		si_write_lock(sb);
++		sysaufs_brs_add(sb, 0);
++		si_write_unlock(sb);
++	}
++	return err;
++}
++
++struct file_system_type aufs_fs_type = {
++	.name		= AUFS_FSTYPE,
++	.fs_flags	=
++		FS_RENAME_DOES_D_MOVE	/* a race between rename and others */
++		| FS_REVAL_DOT,		/* for NFS branch and udba */
++	.get_sb		= aufs_get_sb,
++	.kill_sb	= generic_shutdown_super,
++	/* no need to __module_get() and module_put(). */
++	.owner		= THIS_MODULE,
++};
+diff -uNr test/fs/aufs/super.h aufs2-standalone/fs/aufs/super.h
+--- test/fs/aufs/super.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/super.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,266 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * super_block operations
++ */
++
++#ifndef __AUFS_SUPER_H__
++#define __AUFS_SUPER_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/kobject.h>
++#include <linux/aufs_type.h>
++#include "rwsem.h"
++#include "spl.h"
++#include "wkq.h"
++
++typedef ssize_t (*au_readf_t)(struct file *, char __user *, size_t, loff_t *);
++typedef ssize_t (*au_writef_t)(struct file *, const char __user *, size_t,
++			       loff_t *);
++
++/* policies to select one among multiple writable branches */
++struct au_wbr_copyup_operations {
++	int (*copyup)(struct dentry *dentry);
++};
++
++struct au_wbr_create_operations {
++	int (*create)(struct dentry *dentry, int isdir);
++	int (*init)(struct super_block *sb);
++	int (*fin)(struct super_block *sb);
++};
++
++struct au_wbr_mfs {
++	struct mutex	mfs_lock; /* protect this structure */
++	unsigned long	mfs_jiffy;
++	unsigned long	mfs_expire;
++	aufs_bindex_t	mfs_bindex;
++
++	unsigned long long	mfsrr_bytes;
++	unsigned long long	mfsrr_watermark;
++};
++
++/* sbinfo status flags */
++/*
++ * set true when refresh_dirs() failed at remount time.
++ * then try refreshing dirs at access time again.
++ * if it is false, refreshing dirs at access time is unnecesary
++ */
++#define AuSi_FAILED_REFRESH_DIRS	1
++#define AuSi_MAINTAIN_PLINK		(1 << 1)	/* ioctl */
++#define au_ftest_si(sbinfo, name)	((sbinfo)->au_si_status & AuSi_##name)
++#define au_fset_si(sbinfo, name) \
++	{ (sbinfo)->au_si_status |= AuSi_##name; }
++#define au_fclr_si(sbinfo, name) \
++	{ (sbinfo)->au_si_status &= ~AuSi_##name; }
++
++struct au_branch;
++struct au_sbinfo {
++	/* nowait tasks in the system-wide workqueue */
++	struct au_nowait_tasks	si_nowait;
++
++	struct rw_semaphore	si_rwsem;
++
++	/* branch management */
++	unsigned int		si_generation;
++
++	/* see above flags */
++	unsigned char		au_si_status;
++
++	aufs_bindex_t		si_bend;
++	aufs_bindex_t		si_last_br_id;
++	struct au_branch	**si_branch;
++
++	/* policy to select a writable branch */
++	unsigned char		si_wbr_copyup;
++	unsigned char		si_wbr_create;
++	struct au_wbr_copyup_operations *si_wbr_copyup_ops;
++	struct au_wbr_create_operations *si_wbr_create_ops;
++
++	/* round robin */
++	atomic_t		si_wbr_rr_next;
++
++	/* most free space */
++	struct au_wbr_mfs	si_wbr_mfs;
++
++	/* mount flags */
++	/* include/asm-ia64/siginfo.h defines a macro named si_flags */
++	unsigned int		si_mntflags;
++
++	/* external inode number (bitmap and translation table) */
++	au_readf_t		si_xread;
++	au_writef_t		si_xwrite;
++	struct file		*si_xib;
++	struct mutex		si_xib_mtx; /* protect xib members */
++	unsigned long		*si_xib_buf;
++	unsigned long		si_xib_last_pindex;
++	int			si_xib_next_bit;
++	aufs_bindex_t		si_xino_brid;
++	/* reserved for future use */
++	/* unsigned long long	si_xib_limit; */	/* Max xib file size */
++
++	/* readdir cache time, max, in HZ */
++	unsigned long		si_rdcache;
++
++	/*
++	 * If the number of whiteouts are larger than si_dirwh, leave all of
++	 * them after au_whtmp_ren to reduce the cost of rmdir(2).
++	 * future fsck.aufs or kernel thread will remove them later.
++	 * Otherwise, remove all whiteouts and the dir in rmdir(2).
++	 */
++	unsigned int		si_dirwh;
++
++	/*
++	 * rename(2) a directory with all children.
++	 */
++	/* reserved for future use */
++	/* int			si_rendir; */
++
++	/* pseudo_link list */
++	struct au_splhead	si_plink;
++	wait_queue_head_t	si_plink_wq;
++
++	/*
++	 * sysfs and lifetime management.
++	 * this is not a small structure and it may be a waste of memory in case
++	 * of sysfs is disabled, particulary when many aufs-es are mounted.
++	 * but using sysfs is majority.
++	 */
++	struct kobject		si_kobj;
++
++	/* dirty, necessary for unmounting, sysfs and sysrq */
++	struct super_block	*si_sb;
++};
++
++/* ---------------------------------------------------------------------- */
++
++/* policy to select one among writable branches */
++#define AuWbrCopyup(sbinfo, args...) \
++	((sbinfo)->si_wbr_copyup_ops->copyup(args))
++#define AuWbrCreate(sbinfo, args...) \
++	((sbinfo)->si_wbr_create_ops->create(args))
++
++/* flags for si_read_lock()/aufs_read_lock()/di_read_lock() */
++#define AuLock_DW		1		/* write-lock dentry */
++#define AuLock_IR		(1 << 1)	/* read-lock inode */
++#define AuLock_IW		(1 << 2)	/* write-lock inode */
++#define AuLock_FLUSH		(1 << 3)	/* wait for 'nowait' tasks */
++#define AuLock_DIR		(1 << 4)	/* target is a dir */
++#define au_ftest_lock(flags, name)	((flags) & AuLock_##name)
++#define au_fset_lock(flags, name)	{ (flags) |= AuLock_##name; }
++#define au_fclr_lock(flags, name)	{ (flags) &= ~AuLock_##name; }
++
++/* ---------------------------------------------------------------------- */
++
++/* super.c */
++extern struct file_system_type aufs_fs_type;
++struct inode *au_iget_locked(struct super_block *sb, ino_t ino);
++
++/* sbinfo.c */
++void au_si_free(struct kobject *kobj);
++int au_si_alloc(struct super_block *sb);
++int au_sbr_realloc(struct au_sbinfo *sbinfo, int nbr);
++
++unsigned int au_sigen_inc(struct super_block *sb);
++aufs_bindex_t au_new_br_id(struct super_block *sb);
++
++void aufs_read_lock(struct dentry *dentry, int flags);
++void aufs_read_unlock(struct dentry *dentry, int flags);
++void aufs_write_lock(struct dentry *dentry);
++void aufs_write_unlock(struct dentry *dentry);
++void aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int isdir);
++void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2);
++
++/* wbr_policy.c */
++extern struct au_wbr_copyup_operations au_wbr_copyup_ops[];
++extern struct au_wbr_create_operations au_wbr_create_ops[];
++int au_cpdown_dirs(struct dentry *dentry, aufs_bindex_t bdst);
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct au_sbinfo *au_sbi(struct super_block *sb)
++{
++	return sb->s_fs_info;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* lock superblock. mainly for entry point functions */
++/*
++ * si_noflush_read_lock, si_noflush_write_lock,
++ * si_read_unlock, si_write_unlock, si_downgrade_lock
++ */
++AuSimpleLockRwsemFuncs(si_noflush, struct super_block *sb,
++		       &au_sbi(sb)->si_rwsem);
++AuSimpleUnlockRwsemFuncs(si, struct super_block *sb, &au_sbi(sb)->si_rwsem);
++
++static inline void si_read_lock(struct super_block *sb, int flags)
++{
++	if (au_ftest_lock(flags, FLUSH))
++		au_nwt_flush(&au_sbi(sb)->si_nowait);
++	si_noflush_read_lock(sb);
++}
++
++static inline void si_write_lock(struct super_block *sb)
++{
++	au_nwt_flush(&au_sbi(sb)->si_nowait);
++	si_noflush_write_lock(sb);
++}
++
++static inline int si_read_trylock(struct super_block *sb, int flags)
++{
++	if (au_ftest_lock(flags, FLUSH))
++		au_nwt_flush(&au_sbi(sb)->si_nowait);
++	return si_noflush_read_trylock(sb);
++}
++
++static inline int si_write_trylock(struct super_block *sb, int flags)
++{
++	if (au_ftest_lock(flags, FLUSH))
++		au_nwt_flush(&au_sbi(sb)->si_nowait);
++	return si_noflush_write_trylock(sb);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static inline aufs_bindex_t au_sbend(struct super_block *sb)
++{
++	return au_sbi(sb)->si_bend;
++}
++
++static inline unsigned int au_mntflags(struct super_block *sb)
++{
++	return au_sbi(sb)->si_mntflags;
++}
++
++static inline unsigned int au_sigen(struct super_block *sb)
++{
++	return au_sbi(sb)->si_generation;
++}
++
++static inline struct au_branch *au_sbr(struct super_block *sb,
++				       aufs_bindex_t bindex)
++{
++	return au_sbi(sb)->si_branch[0 + bindex];
++}
++
++static inline void au_xino_brid_set(struct super_block *sb, aufs_bindex_t brid)
++{
++	au_sbi(sb)->si_xino_brid = brid;
++}
++
++static inline aufs_bindex_t au_xino_brid(struct super_block *sb)
++{
++	return au_sbi(sb)->si_xino_brid;
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_SUPER_H__ */
+diff -uNr test/fs/aufs/sysaufs.c aufs2-standalone/fs/aufs/sysaufs.c
+--- test/fs/aufs/sysaufs.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/sysaufs.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,79 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * sysfs interface and lifetime management
++ * they are necessary regardless sysfs is disabled.
++ */
++
++#include <linux/fs.h>
++#include <linux/random.h>
++#include <linux/sysfs.h>
++#include "aufs.h"
++
++unsigned long sysaufs_si_mask;
++struct kset *sysaufs_ket;
++
++#define AuSiAttr(_name) { \
++	.attr   = { .name = __stringify(_name), .mode = 0444 },	\
++	.show   = sysaufs_si_##_name,				\
++}
++
++static struct sysaufs_si_attr sysaufs_si_attr_xino = AuSiAttr(xino);
++struct attribute *sysaufs_si_attrs[] = {
++	&sysaufs_si_attr_xino.attr,
++	NULL,
++};
++
++static struct sysfs_ops au_sbi_ops = {
++	.show   = sysaufs_si_show
++};
++
++static struct kobj_type au_sbi_ktype = {
++	.release	= au_si_free,
++	.sysfs_ops	= &au_sbi_ops,
++	.default_attrs	= sysaufs_si_attrs
++};
++
++/* ---------------------------------------------------------------------- */
++
++int sysaufs_si_init(struct au_sbinfo *sbinfo)
++{
++	int err;
++
++	sbinfo->si_kobj.kset = sysaufs_ket;
++	err = kobject_init_and_add(&sbinfo->si_kobj, &au_sbi_ktype,
++				   /*&sysaufs_ket->kobj*/NULL,
++				   "si_%lx", sysaufs_si_id(sbinfo));
++	return err;
++}
++
++void sysaufs_fin(void)
++{
++	sysfs_remove_group(&sysaufs_ket->kobj, sysaufs_attr_group);
++	kset_unregister(sysaufs_ket);
++}
++
++int __init sysaufs_init(void)
++{
++	int err;
++
++	get_random_bytes(&sysaufs_si_mask, sizeof(sysaufs_si_mask));
++
++	sysaufs_ket = kset_create_and_add(AUFS_NAME, NULL, fs_kobj);
++	err = PTR_ERR(sysaufs_ket);
++	if (IS_ERR(sysaufs_ket))
++		goto out;
++	err = sysfs_create_group(&sysaufs_ket->kobj, sysaufs_attr_group);
++	if (unlikely(err))
++		kset_unregister(sysaufs_ket);
++
++ out:
++	return err;
++}
+diff -uNr test/fs/aufs/sysaufs.h aufs2-standalone/fs/aufs/sysaufs.h
+--- test/fs/aufs/sysaufs.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/sysaufs.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,102 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * sysfs interface and mount lifetime management
++ */
++
++#ifndef __SYSAUFS_H__
++#define __SYSAUFS_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/sysfs.h>
++#include <linux/aufs_type.h>
++
++struct sysaufs_si_attr {
++	struct attribute attr;
++	int (*show)(struct seq_file *seq, struct super_block *sb);
++};
++
++/* ---------------------------------------------------------------------- */
++
++/* sysaufs.c */
++extern unsigned long sysaufs_si_mask;
++extern struct kset *sysaufs_ket;
++extern struct attribute *sysaufs_si_attrs[];
++int sysaufs_si_init(struct au_sbinfo *sbinfo);
++int __init sysaufs_init(void);
++void sysaufs_fin(void);
++
++/* ---------------------------------------------------------------------- */
++
++/* some people doesn't like to show a pointer in kernel */
++static inline unsigned long sysaufs_si_id(struct au_sbinfo *sbinfo)
++{
++	return sysaufs_si_mask ^ (unsigned long)sbinfo;
++}
++
++struct au_branch;
++#ifdef CONFIG_SYSFS
++/* sysfs.c */
++extern struct attribute_group *sysaufs_attr_group;
++extern struct kobj_type *sysaufs_ktype;
++
++int sysaufs_si_xino(struct seq_file *seq, struct super_block *sb);
++ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
++			 char *buf);
++
++void sysaufs_br_init(struct au_branch *br);
++void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex);
++void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex);
++
++#define sysaufs_brs_init()	do {} while (0)
++
++#else
++#define sysaufs_attr_group	NULL
++#define sysaufs_ktype		NULL
++
++static inline
++int sysaufs_si_xino(struct seq_file *seq, struct super_block *sb)
++{
++	return 0;
++}
++
++static inline
++ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
++			 char *buf)
++{
++	return 0;
++}
++
++static inline void sysaufs_br_init(struct au_branch *br)
++{
++	/* empty */
++}
++
++static inline void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
++{
++	/* nothing */
++}
++
++static inline void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
++{
++	/* nothing */
++}
++
++static inline void sysaufs_brs_init(void)
++{
++	sysaufs_brs = 0;
++}
++
++#endif /* CONFIG_SYSFS */
++
++#endif /* __KERNEL__ */
++#endif /* __SYSAUFS_H__ */
+diff -uNr test/fs/aufs/sysfs.c aufs2-standalone/fs/aufs/sysfs.c
+--- test/fs/aufs/sysfs.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/sysfs.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,308 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * sysfs interface
++ */
++
++#include <linux/fs.h>
++#include <linux/seq_file.h>
++#include <linux/sysfs.h>
++#include "aufs.h"
++
++#ifdef CONFIG_AUFS_DEBUG
++static ssize_t debug_show(struct kobject *kobj __maybe_unused,
++			  struct kobj_attribute *attr __maybe_unused,
++			  char *buf)
++{
++	return sprintf(buf, "%d\n", au_debug_test());
++}
++
++static ssize_t debug_store(struct kobject *kobj __maybe_unused,
++			   struct kobj_attribute *attr __maybe_unused,
++			   const char *buf, size_t sz)
++{
++	if (unlikely(!sz || (*buf != '0' && *buf != '1')))
++		return -EOPNOTSUPP;
++
++	if (*buf == '0')
++		au_debug(0);
++	else if (*buf == '1')
++		au_debug(1);
++	return sz;
++}
++
++static struct kobj_attribute au_debug_attr = __ATTR(debug, S_IRUGO | S_IWUSR,
++						    debug_show, debug_store);
++#endif
++
++static struct attribute *au_attr[] = {
++#ifdef CONFIG_AUFS_DEBUG
++	&au_debug_attr.attr,
++#endif
++	NULL,	/* need to NULL terminate the list of attributes */
++};
++
++static struct attribute_group sysaufs_attr_group_body = {
++	.attrs = au_attr
++};
++
++struct attribute_group *sysaufs_attr_group = &sysaufs_attr_group_body;
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * they are copied from linux/lib/kobject.c,
++ * and will be exported in the future.
++ */
++static ssize_t au_attr_show(struct kobject *kobj, struct attribute *attr,
++			    char *buf)
++{
++	struct kobj_attribute *kattr;
++	ssize_t ret = -EIO;
++
++	kattr = container_of(attr, struct kobj_attribute, attr);
++	if (kattr->show)
++		ret = kattr->show(kobj, kattr, buf);
++	return ret;
++}
++
++#ifdef CONFIG_AUFS_DEBUG
++static ssize_t au_attr_store(struct kobject *kobj, struct attribute *attr,
++			     const char *buf, size_t count)
++{
++	struct kobj_attribute *kattr;
++	ssize_t ret = -EIO;
++
++	kattr = container_of(attr, struct kobj_attribute, attr);
++	if (kattr->store)
++		ret = kattr->store(kobj, kattr, buf, count);
++	return ret;
++}
++#endif
++
++static struct sysfs_ops sysaufs_ops = {
++	.show   = au_attr_show,
++#ifdef CONFIG_AUFS_DEBUG
++	.store  = au_attr_store
++#endif
++};
++
++static struct kobj_type sysaufs_ktype_body = {
++	.sysfs_ops = &sysaufs_ops
++};
++struct kobj_type *sysaufs_ktype = &sysaufs_ktype_body;
++
++/* ---------------------------------------------------------------------- */
++
++static int sysaufs_sbi_xi(struct seq_file *seq, struct file *xf,
++			  struct kstat *st)
++{
++	int err;
++
++	err = vfs_getattr(xf->f_vfsmnt, xf->f_dentry, st);
++	if (!err) {
++		seq_printf(seq, "%llux%lu %lld",
++			   st->blocks, st->blksize, (long long)st->size);
++		seq_putc(seq, '\n');
++	} else
++		seq_printf(seq, "err %d\n", err);
++
++	return err;
++}
++
++int sysaufs_si_xino(struct seq_file *seq, struct super_block *sb)
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct kstat st;
++	struct au_sbinfo *sbinfo;
++	struct file *xf;
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	if (!au_opt_test(au_mntflags(sb), XINO))
++		goto out; /* success */
++
++	xf = sbinfo->si_xib;
++	err = au_xino_path(seq, xf);
++	seq_putc(seq, '\n');
++	if (!err)
++		err = sysaufs_sbi_xi(seq, xf, &st);
++
++	bend = au_sbend(sb);
++	for (bindex = 0; !err && bindex <= bend; bindex++) {
++		xf = au_sbr(sb, bindex)->br_xino.xi_file;
++		if (!xf)
++			continue;
++
++		seq_printf(seq, "%d: ", bindex);
++		err = vfs_getattr(xf->f_vfsmnt, xf->f_dentry, &st);
++		if (!err) {
++			seq_printf(seq, "%ld, %llux%lu %lld",
++				   (long)file_count(xf), st.blocks, st.blksize,
++				   (long long)st.size);
++			seq_putc(seq, '\n');
++		} else
++			seq_printf(seq, "err %d\n", err);
++	}
++
++ out:
++	return err;
++}
++
++/*
++ * the lifetime of branch is independent from the entry under sysfs.
++ * sysfs handles the lifetime of the entry, and never call ->show() after it is
++ * unlinked.
++ */
++#define SysaufsBr_PREFIX "br"
++static int sysaufs_sbi_br(struct seq_file *seq, struct super_block *sb,
++			  aufs_bindex_t bindex)
++{
++	int err;
++	struct path path;
++	struct dentry *root;
++	struct au_branch *br;
++
++	err = -ENOENT;
++	if (unlikely(au_sbend(sb) < bindex))
++		goto out;
++
++	err = 0;
++	root = sb->s_root;
++	di_read_lock_parent(root, !AuLock_IR);
++	br = au_sbr(sb, bindex);
++	path.mnt = br->br_mnt;
++	path.dentry = au_h_dptr(root, bindex);
++	au_seq_path(seq, &path);
++	di_read_unlock(root, !AuLock_IR);
++	seq_printf(seq, "=%s\n", au_optstr_br_perm(br->br_perm));
++
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static struct seq_file *au_seq(char *p, ssize_t len)
++{
++	struct seq_file *seq;
++
++	seq = kzalloc(sizeof(*seq), GFP_NOFS);
++	if (seq) {
++		/* mutex_init(&seq.lock); */
++		seq->buf = p;
++		seq->size = len;
++		return seq; /* success */
++	}
++
++	seq = ERR_PTR(-ENOMEM);
++	return seq;
++}
++
++/* todo: file size may exceed PAGE_SIZE */
++ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
++			 char *buf)
++{
++	ssize_t err;
++	long l;
++	struct au_sbinfo *sbinfo;
++	struct super_block *sb;
++	struct seq_file *seq;
++	char *name;
++	struct attribute **cattr;
++
++	sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
++	sb = sbinfo->si_sb;
++	si_noflush_read_lock(sb);
++
++	seq = au_seq(buf, PAGE_SIZE);
++	err = PTR_ERR(seq);
++	if (IS_ERR(seq))
++		goto out;
++
++	name = (void *)attr->name;
++	cattr = sysaufs_si_attrs;
++	while (*cattr) {
++		if (!strcmp(name, (*cattr)->name)) {
++			err = container_of(*cattr, struct sysaufs_si_attr, attr)
++				->show(seq, sb);
++			goto out_seq;
++		}
++		cattr++;
++	}
++
++	if (!strncmp(name, SysaufsBr_PREFIX, sizeof(SysaufsBr_PREFIX) - 1)) {
++		name += sizeof(SysaufsBr_PREFIX) - 1;
++		err = strict_strtol(name, 10, &l);
++		if (!err)
++			err = sysaufs_sbi_br(seq, sb, (aufs_bindex_t)l);
++		goto out_seq;
++	}
++	BUG();
++
++ out_seq:
++	if (!err) {
++		err = seq->count;
++		/* sysfs limit */
++		if (unlikely(err == PAGE_SIZE))
++			err = -EFBIG;
++	}
++	kfree(seq);
++ out:
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void sysaufs_br_init(struct au_branch *br)
++{
++	br->br_attr.name = br->br_name;
++	br->br_attr.mode = S_IRUGO;
++	br->br_attr.owner = THIS_MODULE;
++}
++
++void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
++{
++	struct au_sbinfo *sbinfo;
++	aufs_bindex_t bend;
++
++	if (!sysaufs_brs)
++		return;
++
++	sbinfo = au_sbi(sb);
++	bend = au_sbend(sb);
++	for (; bindex <= bend; bindex++)
++		sysfs_remove_file(&sbinfo->si_kobj,
++				  &au_sbr(sb, bindex)->br_attr);
++}
++
++void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
++{
++	int err;
++	aufs_bindex_t bend;
++	struct kobject *kobj;
++	struct au_branch *br;
++
++	if (!sysaufs_brs)
++		return;
++
++	kobj = &au_sbi(sb)->si_kobj;
++	bend = au_sbend(sb);
++	for (; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		snprintf(br->br_name, sizeof(br->br_name),
++			 SysaufsBr_PREFIX "%d", bindex);
++		err = sysfs_create_file(kobj, &br->br_attr);
++		if (unlikely(err))
++			AuWarn("failed %s under sysfs(%d)\n", br->br_name, err);
++	}
++}
+diff -uNr test/fs/aufs/sysrq.c aufs2-standalone/fs/aufs/sysrq.c
+--- test/fs/aufs/sysrq.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/sysrq.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,106 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * magic sysrq hanlder
++ */
++
++#include <linux/fs.h>
++#include <linux/module.h>
++#include <linux/moduleparam.h>
++/* #include <linux/sysrq.h> */
++#include "aufs.h"
++
++/* ---------------------------------------------------------------------- */
++
++static void sysrq_sb(struct super_block *sb)
++{
++	char *plevel;
++	struct au_sbinfo *sbinfo;
++	struct file *file;
++
++	plevel = au_plevel;
++	au_plevel = KERN_WARNING;
++	au_debug(1);
++
++	sbinfo = au_sbi(sb);
++	pr_warning("si=%lx\n", sysaufs_si_id(sbinfo));
++	pr_warning(AUFS_NAME ": superblock\n");
++	au_dpri_sb(sb);
++	pr_warning(AUFS_NAME ": root dentry\n");
++	au_dpri_dentry(sb->s_root);
++	pr_warning(AUFS_NAME ": root inode\n");
++	au_dpri_inode(sb->s_root->d_inode);
++#if 0
++	struct inode *i;
++	pr_warning(AUFS_NAME ": isolated inode\n");
++	list_for_each_entry(i, &sb->s_inodes, i_sb_list)
++		if (list_empty(&i->i_dentry))
++			au_dpri_inode(i);
++#endif
++	pr_warning(AUFS_NAME ": files\n");
++	list_for_each_entry(file, &sb->s_files, f_u.fu_list)
++		if (!special_file(file->f_dentry->d_inode->i_mode))
++			au_dpri_file(file);
++
++	au_plevel = plevel;
++	au_debug(0);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* module parameter */
++static char *aufs_sysrq_key = "a";
++module_param_named(sysrq, aufs_sysrq_key, charp, S_IRUGO);
++MODULE_PARM_DESC(sysrq, "MagicSysRq key for " AUFS_NAME);
++
++static void au_sysrq(int key __maybe_unused,
++		     struct tty_struct *tty __maybe_unused)
++{
++	struct kobject *kobj;
++	struct au_sbinfo *sbinfo;
++
++	/* spin_lock(&sysaufs_ket->list_lock); */
++	list_for_each_entry(kobj, &sysaufs_ket->list, entry) {
++		sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
++		sysrq_sb(sbinfo->si_sb);
++	}
++	/* spin_unlock(&sysaufs_ket->list_lock); */
++}
++
++static struct sysrq_key_op au_sysrq_op = {
++	.handler	= au_sysrq,
++	.help_msg	= "Aufs",
++	.action_msg	= "Aufs",
++	.enable_mask	= SYSRQ_ENABLE_DUMP
++};
++
++/* ---------------------------------------------------------------------- */
++
++int __init au_sysrq_init(void)
++{
++	int err;
++	char key;
++
++	err = -1;
++	key = *aufs_sysrq_key;
++	if ('a' <= key && key <= 'z')
++		err = register_sysrq_key(key, &au_sysrq_op);
++	if (unlikely(err))
++		AuErr("err %d, sysrq=%c\n", err, key);
++	return err;
++}
++
++void au_sysrq_fin(void)
++{
++	int err;
++	err = unregister_sysrq_key(*aufs_sysrq_key, &au_sysrq_op);
++	if (unlikely(err))
++		AuErr("err %d (ignored)\n", err);
++}
+diff -uNr test/fs/aufs/vdir.c aufs2-standalone/fs/aufs/vdir.c
+--- test/fs/aufs/vdir.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/vdir.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,776 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * virtual or vertical directory
++ */
++
++#include "aufs.h"
++
++static int calc_size(int namelen)
++{
++	int sz;
++	const int mask = sizeof(ino_t) - 1;
++
++	BUILD_BUG_ON(sizeof(ino_t) != sizeof(long));
++
++	sz = sizeof(struct au_vdir_de) + namelen;
++	if (sz & mask) {
++		sz += sizeof(ino_t);
++		sz &= ~mask;
++	}
++
++	AuDebugOn(sz % sizeof(ino_t));
++	return sz;
++}
++
++static int set_deblk_end(union au_vdir_deblk_p *p,
++			 union au_vdir_deblk_p *deblk_end)
++{
++	if (calc_size(0) <= deblk_end->p - p->p) {
++		p->de->de_str.len = 0;
++		/* smp_mb(); */
++		return 0;
++	}
++	return -1; /* error */
++}
++
++/* returns true or false */
++static int is_deblk_end(union au_vdir_deblk_p *p,
++			union au_vdir_deblk_p *deblk_end)
++{
++	if (calc_size(0) <= deblk_end->p - p->p)
++		return !p->de->de_str.len;
++	return 1;
++}
++
++static au_vdir_deblk_t *last_deblk(struct au_vdir *vdir)
++{
++	return vdir->vd_deblk[vdir->vd_nblk - 1];
++}
++
++void au_nhash_init(struct au_nhash *nhash)
++{
++	int i;
++	struct hlist_head *heads;
++
++	heads = nhash->heads;
++	for (i = 0; i < AuSize_NHASH; i++)
++		INIT_HLIST_HEAD(heads++);
++}
++
++struct au_nhash *au_nhash_new(gfp_t gfp)
++{
++	struct au_nhash *nhash;
++
++	nhash = kmalloc(sizeof(*nhash), gfp);
++	if (nhash) {
++		au_nhash_init(nhash);
++		return nhash;
++	}
++	return ERR_PTR(-ENOMEM);
++}
++
++void au_nhash_del(struct au_nhash *nhash)
++{
++	au_nhash_fin(nhash);
++	kfree(nhash);
++}
++
++void au_nhash_move(struct au_nhash *dst, struct au_nhash *src)
++{
++	int i;
++	struct hlist_head *dsth, *srch;
++
++	*dst = *src;
++	srch = src->heads;
++	dsth = dst->heads;
++	for (i = 0; i < AuSize_NHASH; i++) {
++		if (dsth->first)
++			dsth->first->pprev = &dsth->first;
++		dsth++;
++		INIT_HLIST_HEAD(srch++);
++	}
++	/* smp_mb(); */
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_nhash_fin(struct au_nhash *whlist)
++{
++	int i;
++	struct hlist_head *head;
++	struct au_vdir_wh *tpos;
++	struct hlist_node *pos, *n;
++
++	head = whlist->heads;
++	for (i = 0; i < AuSize_NHASH; i++) {
++		hlist_for_each_entry_safe(tpos, pos, n, head, wh_hash) {
++			/* hlist_del(pos); */
++			kfree(tpos);
++		}
++		head++;
++	}
++}
++
++int au_nhash_test_longer_wh(struct au_nhash *whlist, aufs_bindex_t btgt,
++			    int limit)
++{
++	int n, i;
++	struct hlist_head *head;
++	struct au_vdir_wh *tpos;
++	struct hlist_node *pos;
++
++	n = 0;
++	head = whlist->heads;
++	for (i = 0; i < AuSize_NHASH; i++) {
++		hlist_for_each_entry(tpos, pos, head, wh_hash)
++			if (tpos->wh_bindex == btgt && ++n > limit)
++				return 1;
++		head++;
++	}
++	return 0;
++}
++
++static unsigned int au_name_hash(const unsigned char *name, unsigned int len)
++{
++	return full_name_hash(name, len) % AuSize_NHASH;
++}
++
++/* returns found or not */
++int au_nhash_test_known_wh(struct au_nhash *whlist, char *name, int namelen)
++{
++	struct hlist_head *head;
++	struct au_vdir_wh *tpos;
++	struct hlist_node *pos;
++	struct au_vdir_destr *str;
++
++	head = whlist->heads + au_name_hash(name, namelen);
++	hlist_for_each_entry(tpos, pos, head, wh_hash) {
++		str = &tpos->wh_str;
++		AuDbg("%.*s\n", str->len, str->name);
++		if (str->len == namelen && !memcmp(str->name, name, namelen))
++			return 1;
++	}
++	return 0;
++}
++
++int au_nhash_append_wh(struct au_nhash *whlist, char *name, int namelen,
++		       aufs_bindex_t bindex)
++{
++	int err;
++	struct au_vdir_destr *str;
++	struct au_vdir_wh *wh;
++
++	err = -ENOMEM;
++	wh = kmalloc(sizeof(*wh) + namelen, GFP_NOFS);
++	if (unlikely(!wh))
++		goto out;
++
++	err = 0;
++	wh->wh_bindex = bindex;
++	str = &wh->wh_str;
++	str->len = namelen;
++	memcpy(str->name, name, namelen);
++	hlist_add_head(&wh->wh_hash,
++		       whlist->heads + au_name_hash(name, namelen));
++	/* smp_mb(); */
++
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_vdir_free(struct au_vdir *vdir)
++{
++	au_vdir_deblk_t **deblk;
++
++	deblk = vdir->vd_deblk;
++	while (vdir->vd_nblk--)
++		kfree(*deblk++);
++	kfree(vdir->vd_deblk);
++	au_cache_free_vdir(vdir);
++}
++
++static int append_deblk(struct au_vdir *vdir)
++{
++	int err, sz, i;
++	au_vdir_deblk_t **o;
++	union au_vdir_deblk_p p, deblk_end;
++
++	err = -ENOMEM;
++	sz = sizeof(*o) * vdir->vd_nblk;
++	o = au_kzrealloc(vdir->vd_deblk, sz, sz + sizeof(*o), GFP_NOFS);
++	if (unlikely(!o))
++		goto out;
++
++	vdir->vd_deblk = o;
++	p.deblk = kmalloc(sizeof(*p.deblk), GFP_NOFS);
++	if (p.deblk) {
++		i = vdir->vd_nblk++;
++		vdir->vd_deblk[i] = p.deblk;
++		vdir->vd_last.i = i;
++		vdir->vd_last.p.p = p.p;
++		deblk_end.deblk = p.deblk + 1;
++		err = set_deblk_end(&p, &deblk_end);
++	}
++
++ out:
++	return err;
++}
++
++static struct au_vdir *alloc_vdir(void)
++{
++	struct au_vdir *vdir;
++	int err;
++
++	err = -ENOMEM;
++	vdir = au_cache_alloc_vdir();
++	if (unlikely(!vdir))
++		goto out;
++
++	vdir->vd_deblk = kzalloc(sizeof(*vdir->vd_deblk), GFP_NOFS);
++	if (unlikely(!vdir->vd_deblk))
++		goto out_free;
++
++	vdir->vd_nblk = 0;
++	vdir->vd_version = 0;
++	vdir->vd_jiffy = 0;
++	err = append_deblk(vdir);
++	if (!err)
++		return vdir; /* success */
++
++	kfree(vdir->vd_deblk);
++
++ out_free:
++	au_cache_free_vdir(vdir);
++ out:
++	vdir = ERR_PTR(err);
++	return vdir;
++}
++
++static int reinit_vdir(struct au_vdir *vdir)
++{
++	int err;
++	union au_vdir_deblk_p p, deblk_end;
++
++	while (vdir->vd_nblk > 1) {
++		kfree(vdir->vd_deblk[vdir->vd_nblk - 1]);
++		vdir->vd_deblk[vdir->vd_nblk - 1] = NULL;
++		vdir->vd_nblk--;
++	}
++	p.deblk = vdir->vd_deblk[0];
++	deblk_end.deblk = p.deblk + 1;
++	err = set_deblk_end(&p, &deblk_end);
++	vdir->vd_version = 0;
++	vdir->vd_jiffy = 0;
++	vdir->vd_last.i = 0;
++	vdir->vd_last.p.deblk = vdir->vd_deblk[0];
++	/* smp_mb(); */
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void free_dehlist(struct au_nhash *dehlist)
++{
++	int i;
++	struct hlist_head *head;
++	struct au_vdir_dehstr *tpos;
++	struct hlist_node *pos, *n;
++
++	head = dehlist->heads;
++	for (i = 0; i < AuSize_NHASH; i++) {
++		hlist_for_each_entry_safe(tpos, pos, n, head, hash) {
++			/* hlist_del(pos); */
++			au_cache_free_dehstr(tpos);
++		}
++		head++;
++	}
++}
++
++/* returns found(true) or not */
++static int test_known(struct au_nhash *delist, char *name, int namelen)
++{
++	struct hlist_head *head;
++	struct au_vdir_dehstr *tpos;
++	struct hlist_node *pos;
++	struct au_vdir_destr *str;
++
++	head = delist->heads + au_name_hash(name, namelen);
++	hlist_for_each_entry(tpos, pos, head, hash) {
++		str = tpos->str;
++		AuDbg("%.*s\n", str->len, str->name);
++		if (str->len == namelen && !memcmp(str->name, name, namelen))
++			return 1;
++	}
++	return 0;
++
++}
++
++static int append_de(struct au_vdir *vdir, char *name, int namelen, ino_t ino,
++		     unsigned int d_type, struct au_nhash *delist)
++{
++	int err, sz;
++	union au_vdir_deblk_p p, *room, deblk_end;
++	struct au_vdir_dehstr *dehstr;
++
++	p.deblk = last_deblk(vdir);
++	deblk_end.deblk = p.deblk + 1;
++	room = &vdir->vd_last.p;
++	AuDebugOn(room->p < p.p || deblk_end.p <= room->p
++		  || !is_deblk_end(room, &deblk_end));
++
++	sz = calc_size(namelen);
++	if (unlikely(sz > deblk_end.p - room->p)) {
++		err = append_deblk(vdir);
++		if (unlikely(err))
++			goto out;
++
++		p.deblk = last_deblk(vdir);
++		deblk_end.deblk = p.deblk + 1;
++		/* smp_mb(); */
++		AuDebugOn(room->p != p.p);
++	}
++
++	err = -ENOMEM;
++	dehstr = au_cache_alloc_dehstr();
++	if (unlikely(!dehstr))
++		goto out;
++
++	dehstr->str = &room->de->de_str;
++	hlist_add_head(&dehstr->hash,
++		       delist->heads + au_name_hash(name, namelen));
++	room->de->de_ino = ino;
++	room->de->de_type = d_type;
++	room->de->de_str.len = namelen;
++	memcpy(room->de->de_str.name, name, namelen);
++
++	err = 0;
++	room->p += sz;
++	if (unlikely(set_deblk_end(room, &deblk_end)))
++		err = append_deblk(vdir);
++	/* smp_mb(); */
++
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_ino(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		  unsigned int d_type, ino_t *ino)
++{
++	int err;
++	struct mutex *mtx;
++	const int isdir = (d_type == DT_DIR);
++
++	/* prevent hardlinks from race condition */
++	mtx = NULL;
++	if (!isdir) {
++		mtx = &au_sbr(sb, bindex)->br_xino.xi_nondir_mtx;
++		mutex_lock(mtx);
++	}
++	err = au_xino_read(sb, bindex, h_ino, ino);
++	if (unlikely(err))
++		goto out;
++
++	if (!*ino) {
++		err = -EIO;
++		*ino = au_xino_new_ino(sb);
++		if (unlikely(!*ino))
++			goto out;
++		err = au_xino_write(sb, bindex, h_ino, *ino);
++		if (unlikely(err))
++			goto out;
++	}
++
++ out:
++	if (!isdir)
++		mutex_unlock(mtx);
++	return err;
++}
++
++#define AuFillVdir_CALLED	1
++#define au_ftest_fillvdir(flags, name)	((flags) & AuFillVdir_##name)
++#define au_fset_fillvdir(flags, name)	{ (flags) |= AuFillVdir_##name; }
++#define au_fclr_fillvdir(flags, name)	{ (flags) &= ~AuFillVdir_##name; }
++
++struct fillvdir_arg {
++	struct file		*file;
++	struct au_vdir		*vdir;
++	struct au_nhash		*delist;
++	struct au_nhash		*whlist;
++	aufs_bindex_t		bindex;
++	unsigned int		flags;
++	int			err;
++};
++
++static int fillvdir(void *__arg, const char *__name, int namelen,
++		    loff_t offset __maybe_unused, u64 h_ino,
++		    unsigned int d_type)
++{
++	struct fillvdir_arg *arg = __arg;
++	char *name = (void *)__name;
++	struct super_block *sb;
++	struct au_nhash *delist, *whlist;
++	ino_t ino;
++	aufs_bindex_t bindex, bend;
++
++	bend = arg->bindex;
++	arg->err = 0;
++	au_fset_fillvdir(arg->flags, CALLED);
++	/* smp_mb(); */
++	if (namelen <= AUFS_WH_PFX_LEN
++	    || memcmp(name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
++		delist = arg->delist;
++		for (bindex = 0; bindex < bend; bindex++)
++			if (test_known(delist++, name, namelen)
++			    || au_nhash_test_known_wh(arg->whlist + bindex,
++						      name, namelen))
++				goto out; /* already exists or whiteouted */
++
++		ino = 1; /* why does gcc warn? */
++		sb = arg->file->f_dentry->d_sb;
++		arg->err = au_ino(sb, bend, h_ino, d_type, &ino);
++		if (!arg->err)
++			arg->err = append_de(arg->vdir, name, namelen, ino,
++					     d_type, arg->delist + bend);
++	} else {
++		name += AUFS_WH_PFX_LEN;
++		namelen -= AUFS_WH_PFX_LEN;
++		whlist = arg->whlist;
++		for (bindex = 0; bindex < bend; bindex++)
++			if (au_nhash_test_known_wh(whlist++, name, namelen))
++				goto out; /* already whiteouted */
++
++		ino = 1; /* dummy */
++		if (!arg->err)
++			arg->err = au_nhash_append_wh
++				(arg->whlist + bend, name, namelen, bend);
++	}
++
++ out:
++	if (!arg->err)
++		arg->vdir->vd_jiffy = jiffies;
++	/* smp_mb(); */
++	AuTraceErr(arg->err);
++	return arg->err;
++}
++
++static int au_do_read_vdir(struct fillvdir_arg *arg)
++{
++	int err;
++	loff_t offset;
++	aufs_bindex_t bend, bindex, bstart;
++	struct file *hf, *file;
++	struct au_nhash *delist, *whlist;
++
++	err = -ENOMEM;
++	bend = au_fbend(arg->file);
++	arg->delist = kmalloc(sizeof(*arg->delist) * (bend + 1), GFP_NOFS);
++	if (unlikely(!arg->delist))
++		goto out;
++	arg->whlist = kmalloc(sizeof(*arg->whlist) * (bend + 1), GFP_NOFS);
++	if (unlikely(!arg->whlist))
++		goto out_delist;
++
++	err = 0;
++	delist = arg->delist;
++	whlist = arg->whlist;
++	for (bindex = 0; bindex <= bend; bindex++) {
++		au_nhash_init(delist++);
++		au_nhash_init(whlist++);
++	}
++
++	arg->flags = 0;
++	file = arg->file;
++	bstart = au_fbstart(file);
++	for (bindex = bstart; !err && bindex <= bend; bindex++) {
++		hf = au_h_fptr(file, bindex);
++		if (!hf)
++			continue;
++
++		offset = vfsub_llseek(hf, 0, SEEK_SET);
++		err = offset;
++		if (unlikely(offset))
++			break;
++
++		arg->bindex = bindex;
++		do {
++			arg->err = 0;
++			au_fclr_fillvdir(arg->flags, CALLED);
++			/* smp_mb(); */
++			err = vfsub_readdir(hf, fillvdir, arg);
++			if (err >= 0)
++				err = arg->err;
++		} while (!err && au_ftest_fillvdir(arg->flags, CALLED));
++	}
++
++	delist = arg->delist + bstart;
++	whlist = arg->whlist + bstart;
++	for (bindex = bstart; bindex <= bend; bindex++) {
++		free_dehlist(delist++);
++		au_nhash_fin(whlist++);
++	}
++	kfree(arg->whlist);
++
++ out_delist:
++	kfree(arg->delist);
++ out:
++	return err;
++}
++
++static int read_vdir(struct file *file, int may_read)
++{
++	int err;
++	unsigned long expire;
++	unsigned char do_read;
++	struct fillvdir_arg arg;
++	struct inode *inode;
++	struct au_vdir *vdir, *allocated;
++
++	err = 0;
++	inode = file->f_dentry->d_inode;
++	IMustLock(inode);
++	allocated = NULL;
++	do_read = 0;
++	expire = au_sbi(inode->i_sb)->si_rdcache;
++	vdir = au_ivdir(inode);
++	if (!vdir) {
++		do_read = 1;
++		vdir = alloc_vdir();
++		err = PTR_ERR(vdir);
++		if (IS_ERR(vdir))
++			goto out;
++		err = 0;
++		allocated = vdir;
++	} else if (may_read
++		   && (inode->i_version != vdir->vd_version
++		       || time_after(jiffies, vdir->vd_jiffy + expire))) {
++		do_read = 1;
++		err = reinit_vdir(vdir);
++		if (unlikely(err))
++			goto out;
++	}
++
++	if (!do_read)
++		return 0; /* success */
++
++	arg.file = file;
++	arg.vdir = vdir;
++	err = au_do_read_vdir(&arg);
++	if (!err) {
++		/* file->f_pos = 0; */
++		vdir->vd_version = inode->i_version;
++		vdir->vd_last.i = 0;
++		vdir->vd_last.p.deblk = vdir->vd_deblk[0];
++		if (allocated)
++			au_set_ivdir(inode, allocated);
++	} else if (allocated)
++		au_vdir_free(allocated);
++
++ out:
++	return err;
++}
++
++static int copy_vdir(struct au_vdir *tgt, struct au_vdir *src)
++{
++	int err, i, rerr, n;
++
++	AuDebugOn(tgt->vd_nblk != 1);
++
++	err = -ENOMEM;
++	if (tgt->vd_nblk < src->vd_nblk) {
++		au_vdir_deblk_t **p;
++
++		p = au_kzrealloc(tgt->vd_deblk, sizeof(*p) * tgt->vd_nblk,
++				 sizeof(*p) * src->vd_nblk, GFP_NOFS);
++		if (unlikely(!p))
++			goto out;
++		tgt->vd_deblk = p;
++	}
++
++	tgt->vd_nblk = src->vd_nblk;
++	n = src->vd_nblk;
++	memcpy(tgt->vd_deblk[0], src->vd_deblk[0], AuSize_DEBLK);
++	/* tgt->vd_last.i = 0; */
++	/* tgt->vd_last.p.deblk = tgt->vd_deblk[0]; */
++	tgt->vd_version = src->vd_version;
++	tgt->vd_jiffy = src->vd_jiffy;
++
++	for (i = 1; i < n; i++) {
++		tgt->vd_deblk[i] = kmalloc(AuSize_DEBLK, GFP_NOFS);
++		if (tgt->vd_deblk[i])
++			memcpy(tgt->vd_deblk[i], src->vd_deblk[i],
++			       AuSize_DEBLK);
++		else
++			goto out;
++	}
++	/* smp_mb(); */
++	return 0; /* success */
++
++ out:
++	rerr = reinit_vdir(tgt);
++	BUG_ON(rerr);
++	return err;
++}
++
++int au_vdir_init(struct file *file)
++{
++	int err;
++	struct inode *inode;
++	struct au_vdir *vdir_cache, *allocated;
++
++	err = read_vdir(file, !file->f_pos);
++	if (unlikely(err))
++		goto out;
++
++	allocated = NULL;
++	vdir_cache = au_fvdir_cache(file);
++	if (!vdir_cache) {
++		vdir_cache = alloc_vdir();
++		err = PTR_ERR(vdir_cache);
++		if (IS_ERR(vdir_cache))
++			goto out;
++		allocated = vdir_cache;
++	} else if (!file->f_pos && vdir_cache->vd_version != file->f_version) {
++		err = reinit_vdir(vdir_cache);
++		if (unlikely(err))
++			goto out;
++	} else
++		return 0; /* success */
++
++	inode = file->f_dentry->d_inode;
++	err = copy_vdir(vdir_cache, au_ivdir(inode));
++	if (!err) {
++		file->f_version = inode->i_version;
++		if (allocated)
++			au_set_fvdir_cache(file, allocated);
++	} else if (allocated)
++		au_vdir_free(allocated);
++
++ out:
++	return err;
++}
++
++static loff_t calc_offset(struct au_vdir *vdir)
++{
++	loff_t offset;
++	union au_vdir_deblk_p p;
++
++	p.deblk = vdir->vd_deblk[vdir->vd_last.i];
++	offset = vdir->vd_last.p.p - p.p;
++	offset += sizeof(*p.deblk) * vdir->vd_last.i;
++	return offset;
++}
++
++/* returns true or false */
++static int seek_vdir(struct file *file)
++{
++	int valid, i, n;
++	loff_t offset;
++	union au_vdir_deblk_p p, deblk_end;
++	struct au_vdir *vdir_cache;
++
++	valid = 1;
++	vdir_cache = au_fvdir_cache(file);
++	offset = calc_offset(vdir_cache);
++	AuDbg("offset %lld\n", offset);
++	if (file->f_pos == offset)
++		goto out;
++
++	vdir_cache->vd_last.i = 0;
++	vdir_cache->vd_last.p.deblk = vdir_cache->vd_deblk[0];
++	if (!file->f_pos)
++		goto out;
++
++	valid = 0;
++	i = file->f_pos / AuSize_DEBLK;
++	AuDbg("i %d\n", i);
++	if (i >= vdir_cache->vd_nblk)
++		goto out;
++
++	n = vdir_cache->vd_nblk;
++	for (; i < n; i++) {
++		p.deblk = vdir_cache->vd_deblk[i];
++		deblk_end.deblk = p.deblk + 1;
++		offset = i;
++		offset *= AuSize_DEBLK;
++		while (!is_deblk_end(&p, &deblk_end) && offset < file->f_pos) {
++			int l;
++
++			l = calc_size(p.de->de_str.len);
++			offset += l;
++			p.p += l;
++		}
++		if (!is_deblk_end(&p, &deblk_end)) {
++			valid = 1;
++			vdir_cache->vd_last.i = i;
++			vdir_cache->vd_last.p = p;
++			break;
++		}
++	}
++
++ out:
++	/* smp_mb(); */
++	AuTraceErr(!valid);
++	return valid;
++}
++
++int au_vdir_fill_de(struct file *file, void *dirent, filldir_t filldir)
++{
++	int err, l;
++	union au_vdir_deblk_p deblk_end;
++	struct au_vdir *vdir_cache;
++	struct au_vdir_de *de;
++
++	BUILD_BUG_ON(AuSize_DEBLK < NAME_MAX || PAGE_SIZE < AuSize_DEBLK);
++
++	vdir_cache = au_fvdir_cache(file);
++	if (!seek_vdir(file))
++		return 0;
++
++	while (1) {
++		deblk_end.deblk
++			= vdir_cache->vd_deblk[vdir_cache->vd_last.i] + 1;
++		while (!is_deblk_end(&vdir_cache->vd_last.p, &deblk_end)) {
++			de = vdir_cache->vd_last.p.de;
++			AuDbg("%.*s, off%lld, i%lu, dt%d\n",
++			      de->de_str.len, de->de_str.name,
++			      file->f_pos, (unsigned long)de->de_ino,
++			      de->de_type);
++			err = filldir(dirent, de->de_str.name, de->de_str.len,
++				      file->f_pos, de->de_ino, de->de_type);
++			if (unlikely(err)) {
++				AuTraceErr(err);
++				/* todo: ignore the error caused by udba? */
++				/* return err; */
++				return 0;
++			}
++
++			l = calc_size(de->de_str.len);
++			vdir_cache->vd_last.p.p += l;
++			file->f_pos += l;
++		}
++		if (vdir_cache->vd_last.i < vdir_cache->vd_nblk - 1) {
++			vdir_cache->vd_last.i++;
++			vdir_cache->vd_last.p.deblk
++				= vdir_cache->vd_deblk[vdir_cache->vd_last.i];
++			file->f_pos = sizeof(*vdir_cache->vd_last.p.deblk)
++				* vdir_cache->vd_last.i;
++			continue;
++		}
++		break;
++	}
++
++	/* smp_mb(); */
++	return 0;
++}
+diff -uNr test/fs/aufs/vfsub.c aufs2-standalone/fs/aufs/vfsub.c
+--- test/fs/aufs/vfsub.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/vfsub.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,639 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * sub-routines for VFS
++ */
++
++#include <linux/uaccess.h>
++#include "aufs.h"
++
++int vfsub_update_h_iattr(struct path *h_path, int *did)
++{
++	int err;
++	struct kstat st;
++	struct super_block *h_sb;
++
++	/* for remote fs, leave work for its getattr or d_revalidate */
++	/* for bad i_attr fs, handle them in aufs_getattr() */
++	/* still some fs may acquire i_mutex. we need to skip them */
++	err = 0;
++	if (!did)
++		did = &err;
++	h_sb = h_path->dentry->d_sb;
++	*did = (!au_test_fs_remote(h_sb) && au_test_fs_refresh_iattr(h_sb));
++	if (*did)
++		err = vfs_getattr(h_path->mnt, h_path->dentry, &st);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct file *vfsub_filp_open(const char *path, int oflags, int mode)
++{
++	struct file *file;
++
++	lockdep_off();
++	file = filp_open(path, oflags, mode);
++	lockdep_on();
++	if (IS_ERR(file))
++		goto out;
++	vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
++
++ out:
++	return file;
++}
++
++int vfsub_kern_path(const char *name, unsigned int flags, struct path *path)
++{
++	int err;
++
++	/* lockdep_off(); */
++	err = kern_path(name, flags, path);
++	/* lockdep_on(); */
++	if (!err && path->dentry->d_inode)
++		vfsub_update_h_iattr(path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++struct dentry *vfsub_lookup_one_len(const char *name, struct dentry *parent,
++				    int len)
++{
++	struct path path = {
++		.mnt = NULL
++	};
++
++	IMustLock(parent->d_inode);
++
++	path.dentry = lookup_one_len(name, parent, len);
++	if (IS_ERR(path.dentry))
++		goto out;
++	if (path.dentry->d_inode)
++		vfsub_update_h_iattr(&path, /*did*/NULL); /*ignore*/
++
++ out:
++	return path.dentry;
++}
++
++struct dentry *vfsub_lookup_hash(struct nameidata *nd)
++{
++	struct path path = {
++		.mnt = nd->path.mnt
++	};
++
++	IMustLock(nd->path.dentry->d_inode);
++
++	path.dentry = lookup_hash(nd);
++	if (!IS_ERR(path.dentry) && path.dentry->d_inode)
++		vfsub_update_h_iattr(&path, /*did*/NULL); /*ignore*/
++
++	return path.dentry;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct dentry *vfsub_lock_rename(struct dentry *d1, struct au_hinode *hdir1,
++				 struct dentry *d2, struct au_hinode *hdir2)
++{
++	struct dentry *d;
++
++	lockdep_off();
++	d = lock_rename(d1, d2);
++	lockdep_on();
++	au_hin_suspend(hdir1);
++	if (hdir1 != hdir2)
++		au_hin_suspend(hdir2);
++
++	return d;
++}
++
++void vfsub_unlock_rename(struct dentry *d1, struct au_hinode *hdir1,
++			 struct dentry *d2, struct au_hinode *hdir2)
++{
++	au_hin_resume(hdir1);
++	if (hdir1 != hdir2)
++		au_hin_resume(hdir2);
++	lockdep_off();
++	unlock_rename(d1, d2);
++	lockdep_on();
++}
++
++/* ---------------------------------------------------------------------- */
++
++int vfsub_create(struct inode *dir, struct path *path, int mode)
++{
++	int err;
++
++	IMustLock(dir);
++
++	if (au_test_fs_null_nd(dir->i_sb))
++		err = vfs_create(dir, path->dentry, mode, NULL);
++	else {
++		struct nameidata h_nd;
++
++		memset(&h_nd, 0, sizeof(h_nd));
++		h_nd.flags = LOOKUP_CREATE;
++		/* cf. fs/namei.c:open_to_namei_flags() */
++		h_nd.intent.open.flags = O_CREAT | O_RDONLY;
++		h_nd.intent.open.flags++;
++		h_nd.intent.open.create_mode = mode;
++		h_nd.path.dentry = path->dentry->d_parent;
++		h_nd.path.mnt = path->mnt;
++		path_get(&h_nd.path);
++		err = vfs_create(dir, path->dentry, mode, &h_nd);
++		path_put(&h_nd.path);
++	}
++
++	if (!err) {
++		struct path tmp = *path;
++		int did;
++
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = path->dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++
++	return err;
++}
++
++int vfsub_symlink(struct inode *dir, struct path *path, const char *symname)
++{
++	int err;
++
++	IMustLock(dir);
++
++	err = vfs_symlink(dir, path->dentry, symname);
++	if (!err) {
++		struct path tmp = *path;
++		int did;
++
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = path->dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++	return err;
++}
++
++int vfsub_mknod(struct inode *dir, struct path *path, int mode, dev_t dev)
++{
++	int err;
++
++	IMustLock(dir);
++
++	err = vfs_mknod(dir, path->dentry, mode, dev);
++	if (!err) {
++		struct path tmp = *path;
++		int did;
++
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = path->dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++	return err;
++}
++
++int vfsub_link(struct dentry *src_dentry, struct inode *dir, struct path *path)
++{
++	int err;
++
++	IMustLock(dir);
++
++	lockdep_off();
++	err = vfs_link(src_dentry, dir, path->dentry);
++	lockdep_on();
++	if (!err) {
++		struct path tmp = *path;
++		int did;
++
++		/* fuse has different memory inode for the same inumber */
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = path->dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++			tmp.dentry = src_dentry;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++	return err;
++}
++
++int vfsub_rename(struct inode *src_dir, struct dentry *src_dentry,
++		 struct inode *dir, struct path *path)
++{
++	int err;
++	struct path tmp = {
++		.dentry	= path->dentry->d_parent,
++		.mnt	= path->mnt
++	};
++
++	IMustLock(dir);
++	IMustLock(src_dir);
++
++	lockdep_off();
++	err = vfs_rename(src_dir, src_dentry, dir, path->dentry);
++	lockdep_on();
++	if (!err) {
++		int did;
++
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = src_dentry;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++			tmp.dentry = src_dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++	return err;
++}
++
++int vfsub_mkdir(struct inode *dir, struct path *path, int mode)
++{
++	int err;
++
++	IMustLock(dir);
++
++	err = vfs_mkdir(dir, path->dentry, mode);
++	if (!err) {
++		struct path tmp = *path;
++		int did;
++
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = path->dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++	return err;
++}
++
++int vfsub_rmdir(struct inode *dir, struct path *path)
++{
++	int err;
++
++	IMustLock(dir);
++
++	lockdep_off();
++	err = vfs_rmdir(dir, path->dentry);
++	lockdep_on();
++	if (!err) {
++		struct path tmp = {
++			.dentry	= path->dentry->d_parent,
++			.mnt	= path->mnt
++		};
++
++		vfsub_update_h_iattr(&tmp, /*did*/NULL); /*ignore*/
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++ssize_t vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
++		     loff_t *ppos)
++{
++	ssize_t err;
++
++	err = vfs_read(file, ubuf, count, ppos);
++	if (err >= 0)
++		vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++/* todo: kernel_read()? */
++ssize_t vfsub_read_k(struct file *file, void *kbuf, size_t count,
++		     loff_t *ppos)
++{
++	ssize_t err;
++	mm_segment_t oldfs;
++
++	oldfs = get_fs();
++	set_fs(KERNEL_DS);
++	err = vfsub_read_u(file, (char __user *)kbuf, count, ppos);
++	set_fs(oldfs);
++	return err;
++}
++
++ssize_t vfsub_write_u(struct file *file, const char __user *ubuf, size_t count,
++		      loff_t *ppos)
++{
++	ssize_t err;
++
++	lockdep_off();
++	err = vfs_write(file, ubuf, count, ppos);
++	lockdep_on();
++	if (err >= 0)
++		vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++ssize_t vfsub_write_k(struct file *file, void *kbuf, size_t count, loff_t *ppos)
++{
++	ssize_t err;
++	mm_segment_t oldfs;
++
++	oldfs = get_fs();
++	set_fs(KERNEL_DS);
++	err = vfsub_write_u(file, (const char __user *)kbuf, count, ppos);
++	set_fs(oldfs);
++	return err;
++}
++
++int vfsub_readdir(struct file *file, filldir_t filldir, void *arg)
++{
++	int err;
++
++	lockdep_off();
++	err = vfs_readdir(file, filldir, arg);
++	lockdep_on();
++	if (err >= 0)
++		vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++long vfsub_splice_to(struct file *in, loff_t *ppos,
++		     struct pipe_inode_info *pipe, size_t len,
++		     unsigned int flags)
++{
++	long err;
++
++	lockdep_off();
++	err = do_splice_to(in, ppos, pipe, len, flags);
++	lockdep_on();
++	if (err >= 0)
++		vfsub_update_h_iattr(&in->f_path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++long vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
++		       loff_t *ppos, size_t len, unsigned int flags)
++{
++	long err;
++
++	lockdep_off();
++	err = do_splice_from(pipe, out, ppos, len, flags);
++	lockdep_on();
++	if (err >= 0)
++		vfsub_update_h_iattr(&out->f_path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++/* cf. open.c:do_sys_truncate() and do_sys_ftruncate() */
++int vfsub_trunc(struct path *h_path, loff_t length, unsigned int attr,
++		struct file *h_file)
++{
++	int err;
++	struct inode *h_inode;
++	union {
++		unsigned int u;
++		fmode_t m;
++	} u;
++
++	h_inode = h_path->dentry->d_inode;
++	if (!h_file) {
++		err = mnt_want_write(h_path->mnt);
++		if (err)
++			goto out;
++		err = inode_permission(h_inode, MAY_WRITE);
++		if (err)
++			goto out_mnt;
++		err = get_write_access(h_inode);
++		if (err)
++			goto out_mnt;
++		u.m = FMODE_WRITE;
++		err = break_lease(h_inode, u.u);
++		if (err)
++			goto out_inode;
++	}
++
++	err = locks_verify_truncate(h_inode, h_file, length);
++	if (!err) {
++		lockdep_off();
++		err = do_truncate(h_path->dentry, length, attr, h_file);
++		lockdep_on();
++	}
++
++ out_inode:
++	if (!h_file)
++		put_write_access(h_inode);
++ out_mnt:
++	if (!h_file)
++		mnt_drop_write(h_path->mnt);
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct au_vfsub_mkdir_args {
++	int *errp;
++	struct inode *dir;
++	struct path *path;
++	int mode;
++};
++
++static void au_call_vfsub_mkdir(void *args)
++{
++	struct au_vfsub_mkdir_args *a = args;
++	*a->errp = vfsub_mkdir(a->dir, a->path, a->mode);
++}
++
++int vfsub_sio_mkdir(struct inode *dir, struct path *path, int mode)
++{
++	int err, do_sio, wkq_err;
++
++	do_sio = au_test_h_perm_sio(dir, MAY_EXEC | MAY_WRITE);
++	if (!do_sio)
++		err = vfsub_mkdir(dir, path, mode);
++	else {
++		struct au_vfsub_mkdir_args args = {
++			.errp	= &err,
++			.dir	= dir,
++			.path	= path,
++			.mode	= mode
++		};
++		wkq_err = au_wkq_wait(au_call_vfsub_mkdir, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	return err;
++}
++
++struct au_vfsub_rmdir_args {
++	int *errp;
++	struct inode *dir;
++	struct path *path;
++};
++
++static void au_call_vfsub_rmdir(void *args)
++{
++	struct au_vfsub_rmdir_args *a = args;
++	*a->errp = vfsub_rmdir(a->dir, a->path);
++}
++
++int vfsub_sio_rmdir(struct inode *dir, struct path *path)
++{
++	int err, do_sio, wkq_err;
++
++	do_sio = au_test_h_perm_sio(dir, MAY_EXEC | MAY_WRITE);
++	if (!do_sio)
++		err = vfsub_rmdir(dir, path);
++	else {
++		struct au_vfsub_rmdir_args args = {
++			.errp	= &err,
++			.dir	= dir,
++			.path	= path
++		};
++		wkq_err = au_wkq_wait(au_call_vfsub_rmdir, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct notify_change_args {
++	int *errp;
++	struct path *path;
++	struct iattr *ia;
++};
++
++static void call_notify_change(void *args)
++{
++	struct notify_change_args *a = args;
++	struct inode *h_inode;
++
++	h_inode = a->path->dentry->d_inode;
++	IMustLock(h_inode);
++
++	*a->errp = -EPERM;
++	if (!IS_IMMUTABLE(h_inode) && !IS_APPEND(h_inode)) {
++		lockdep_off();
++		*a->errp = notify_change(a->path->dentry, a->ia);
++		lockdep_on();
++		if (!*a->errp)
++			vfsub_update_h_iattr(a->path, /*did*/NULL); /*ignore*/
++	}
++	AuTraceErr(*a->errp);
++}
++
++int vfsub_notify_change(struct path *path, struct iattr *ia)
++{
++	int err;
++	struct notify_change_args args = {
++		.errp	= &err,
++		.path	= path,
++		.ia	= ia
++	};
++
++	call_notify_change(&args);
++
++	return err;
++}
++
++int vfsub_sio_notify_change(struct path *path, struct iattr *ia)
++{
++	int err, wkq_err;
++	struct notify_change_args args = {
++		.errp	= &err,
++		.path	= path,
++		.ia	= ia
++	};
++
++	wkq_err = au_wkq_wait(call_notify_change, &args);
++	if (unlikely(wkq_err))
++		err = wkq_err;
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct unlink_args {
++	int *errp;
++	struct inode *dir;
++	struct path *path;
++};
++
++static void call_unlink(void *args)
++{
++	struct unlink_args *a = args;
++	struct dentry *d = a->path->dentry;
++	struct inode *h_inode;
++	const int stop_sillyrename = (au_test_nfs(d->d_sb)
++				      && atomic_read(&d->d_count) == 1);
++
++	IMustLock(a->dir);
++
++	if (!stop_sillyrename)
++		dget(d);
++	h_inode = d->d_inode;
++	if (h_inode)
++		atomic_inc(&h_inode->i_count);
++
++	lockdep_off();
++	*a->errp = vfs_unlink(a->dir, d);
++	lockdep_on();
++	if (!*a->errp) {
++		struct path tmp = {
++			.dentry = d->d_parent,
++			.mnt	= a->path->mnt
++		};
++		vfsub_update_h_iattr(&tmp, /*did*/NULL); /*ignore*/
++	}
++
++	if (!stop_sillyrename)
++		dput(d);
++	if (h_inode)
++		iput(h_inode);
++
++	AuTraceErr(*a->errp);
++}
++
++/*
++ * @dir: must be locked.
++ * @dentry: target dentry.
++ */
++int vfsub_unlink(struct inode *dir, struct path *path, int force)
++{
++	int err;
++	struct unlink_args args = {
++		.errp	= &err,
++		.dir	= dir,
++		.path	= path
++	};
++
++	if (!force)
++		call_unlink(&args);
++	else {
++		int wkq_err;
++
++		wkq_err = au_wkq_wait(call_unlink, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	return err;
++}
+diff -uNr test/fs/aufs/vfsub.h aufs2-standalone/fs/aufs/vfsub.h
+--- test/fs/aufs/vfsub.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/vfsub.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,137 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * sub-routines for VFS
++ */
++
++#ifndef __AUFS_VFSUB_H__
++#define __AUFS_VFSUB_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/fs_stack.h>
++#include <linux/namei.h>
++#include <linux/security.h>
++#include <linux/splice.h>
++
++/* ---------------------------------------------------------------------- */
++
++/* lock subclass for lower inode */
++/* default MAX_LOCKDEP_SUBCLASSES(8) is not enough */
++/* reduce? gave up. */
++enum {
++	AuLsc_I_Begin = I_MUTEX_QUOTA, /* 4 */
++	AuLsc_I_PARENT,		/* lower inode, parent first */
++	AuLsc_I_PARENT2,	/* copyup dirs */
++	AuLsc_I_CHILD,
++	AuLsc_I_CHILD2,
++	AuLsc_I_End
++};
++
++/* to debug easier, do not make them inlined functions */
++#define MtxMustLock(mtx)	AuDebugOn(!mutex_is_locked(mtx))
++#define IMustLock(i)		MtxMustLock(&(i)->i_mutex)
++
++/* ---------------------------------------------------------------------- */
++
++static inline void vfsub_copy_inode_size(struct inode *inode,
++					 struct inode *h_inode)
++{
++	spin_lock(&inode->i_lock);
++	fsstack_copy_inode_size(inode, h_inode);
++	spin_unlock(&inode->i_lock);
++}
++
++int vfsub_update_h_iattr(struct path *h_path, int *did);
++struct file *vfsub_filp_open(const char *path, int oflags, int mode);
++int vfsub_kern_path(const char *name, unsigned int flags, struct path *path);
++struct dentry *vfsub_lookup_one_len(const char *name, struct dentry *parent,
++				    int len);
++struct dentry *vfsub_lookup_hash(struct nameidata *nd);
++
++/* ---------------------------------------------------------------------- */
++
++struct au_hinode;
++struct dentry *vfsub_lock_rename(struct dentry *d1, struct au_hinode *hdir1,
++				 struct dentry *d2, struct au_hinode *hdir2);
++void vfsub_unlock_rename(struct dentry *d1, struct au_hinode *hdir1,
++			 struct dentry *d2, struct au_hinode *hdir2);
++
++int vfsub_create(struct inode *dir, struct path *path, int mode);
++int vfsub_symlink(struct inode *dir, struct path *path,
++		  const char *symname);
++int vfsub_mknod(struct inode *dir, struct path *path, int mode, dev_t dev);
++int vfsub_link(struct dentry *src_dentry, struct inode *dir,
++	       struct path *path);
++int vfsub_rename(struct inode *src_hdir, struct dentry *src_dentry,
++		 struct inode *hdir, struct path *path);
++int vfsub_mkdir(struct inode *dir, struct path *path, int mode);
++int vfsub_rmdir(struct inode *dir, struct path *path);
++
++/* ---------------------------------------------------------------------- */
++
++ssize_t vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
++		     loff_t *ppos);
++ssize_t vfsub_read_k(struct file *file, void *kbuf, size_t count,
++			loff_t *ppos);
++ssize_t vfsub_write_u(struct file *file, const char __user *ubuf, size_t count,
++		      loff_t *ppos);
++ssize_t vfsub_write_k(struct file *file, void *kbuf, size_t count,
++		      loff_t *ppos);
++int vfsub_readdir(struct file *file, filldir_t filldir, void *arg);
++
++static inline void vfsub_file_accessed(struct file *h_file)
++{
++	file_accessed(h_file);
++	vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL); /*ignore*/
++}
++
++static inline void vfsub_touch_atime(struct vfsmount *h_mnt,
++				     struct dentry *h_dentry)
++{
++	struct path h_path = {
++		.dentry	= h_dentry,
++		.mnt	= h_mnt
++	};
++	touch_atime(h_mnt, h_dentry);
++	vfsub_update_h_iattr(&h_path, /*did*/NULL); /*ignore*/
++}
++
++long vfsub_splice_to(struct file *in, loff_t *ppos,
++		     struct pipe_inode_info *pipe, size_t len,
++		     unsigned int flags);
++long vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
++		       loff_t *ppos, size_t len, unsigned int flags);
++int vfsub_trunc(struct path *h_path, loff_t length, unsigned int attr,
++		struct file *h_file);
++
++/* ---------------------------------------------------------------------- */
++
++static inline loff_t vfsub_llseek(struct file *file, loff_t offset, int origin)
++{
++	loff_t err;
++
++	lockdep_off();
++	err = vfs_llseek(file, offset, origin);
++	lockdep_on();
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int vfsub_sio_mkdir(struct inode *dir, struct path *path, int mode);
++int vfsub_sio_rmdir(struct inode *dir, struct path *path);
++int vfsub_sio_notify_change(struct path *path, struct iattr *ia);
++int vfsub_notify_change(struct path *path, struct iattr *ia);
++int vfsub_unlink(struct inode *dir, struct path *path, int force);
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_VFSUB_H__ */
+diff -uNr test/fs/aufs/wbr_policy.c aufs2-standalone/fs/aufs/wbr_policy.c
+--- test/fs/aufs/wbr_policy.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/wbr_policy.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,628 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * policies for selecting one among multiple writable branches
++ */
++
++#include <linux/statfs.h>
++#include "aufs.h"
++
++/* subset of cpup_attr() */
++static noinline_for_stack
++int au_cpdown_attr(struct path *h_path, struct dentry *h_src)
++{
++	int err, sbits;
++	struct iattr ia;
++	struct inode *h_isrc;
++
++	h_isrc = h_src->d_inode;
++	ia.ia_valid = ATTR_FORCE | ATTR_MODE | ATTR_UID | ATTR_GID;
++	ia.ia_mode = h_isrc->i_mode;
++	ia.ia_uid = h_isrc->i_uid;
++	ia.ia_gid = h_isrc->i_gid;
++	sbits = !!(ia.ia_mode & (S_ISUID | S_ISGID));
++	au_cpup_attr_flags(h_path->dentry->d_inode, h_isrc);
++	err = vfsub_sio_notify_change(h_path, &ia);
++
++	/* is this nfs only? */
++	if (!err && sbits && au_test_nfs(h_path->dentry->d_sb)) {
++		ia.ia_valid = ATTR_FORCE | ATTR_MODE;
++		ia.ia_mode = h_isrc->i_mode;
++		err = vfsub_sio_notify_change(h_path, &ia);
++	}
++
++	return err;
++}
++
++#define AuCpdown_PARENT_OPQ	1
++#define AuCpdown_WHED		(1 << 1)
++#define AuCpdown_MADE_DIR	(1 << 2)
++#define AuCpdown_DIROPQ		(1 << 3)
++#define au_ftest_cpdown(flags, name)	((flags) & AuCpdown_##name)
++#define au_fset_cpdown(flags, name)	{ (flags) |= AuCpdown_##name; }
++#define au_fclr_cpdown(flags, name)	{ (flags) &= ~AuCpdown_##name; }
++
++struct au_cpdown_dir_args {
++	struct dentry *parent;
++	unsigned int flags;
++};
++
++static int au_cpdown_dir_opq(struct dentry *dentry, aufs_bindex_t bdst,
++			     struct au_cpdown_dir_args *a)
++{
++	int err;
++	struct dentry *opq_dentry;
++
++	opq_dentry = au_diropq_create(dentry, bdst);
++	err = PTR_ERR(opq_dentry);
++	if (IS_ERR(opq_dentry))
++		goto out;
++	dput(opq_dentry);
++	au_fset_cpdown(a->flags, DIROPQ);
++
++ out:
++	return err;
++}
++
++static int au_cpdown_dir_wh(struct dentry *dentry, struct dentry *h_parent,
++			    struct inode *dir, aufs_bindex_t bdst)
++{
++	int err;
++	struct path h_path;
++	struct au_branch *br;
++
++	br = au_sbr(dentry->d_sb, bdst);
++	h_path.dentry = au_wh_lkup(h_parent, &dentry->d_name, br);
++	err = PTR_ERR(h_path.dentry);
++	if (IS_ERR(h_path.dentry))
++		goto out;
++
++	err = 0;
++	if (h_path.dentry->d_inode) {
++		h_path.mnt = br->br_mnt;
++		err = au_wh_unlink_dentry(au_h_iptr(dir, bdst), &h_path,
++					  dentry);
++	}
++	dput(h_path.dentry);
++
++ out:
++	return err;
++}
++
++static int au_cpdown_dir(struct dentry *dentry, aufs_bindex_t bdst,
++			 struct dentry *h_parent, void *arg)
++{
++	int err, rerr;
++	aufs_bindex_t bend, bopq, bstart;
++	unsigned char parent_opq;
++	struct path h_path;
++	struct dentry *parent;
++	struct inode *h_dir, *h_inode, *inode, *dir;
++	struct au_cpdown_dir_args *args = arg;
++
++	bstart = au_dbstart(dentry);
++	/* dentry is di-locked */
++	parent = dget_parent(dentry);
++	dir = parent->d_inode;
++	h_dir = h_parent->d_inode;
++	AuDebugOn(h_dir != au_h_iptr(dir, bdst));
++	IMustLock(h_dir);
++
++	err = au_lkup_neg(dentry, bdst);
++	if (unlikely(err < 0))
++		goto out;
++	h_path.dentry = au_h_dptr(dentry, bdst);
++	h_path.mnt = au_sbr_mnt(dentry->d_sb, bdst);
++	err = vfsub_sio_mkdir(au_h_iptr(dir, bdst), &h_path,
++			      S_IRWXU | S_IRUGO | S_IXUGO);
++	if (unlikely(err))
++		goto out_put;
++	au_fset_cpdown(args->flags, MADE_DIR);
++
++	bend = au_dbend(dentry);
++	bopq = au_dbdiropq(dentry);
++	au_fclr_cpdown(args->flags, WHED);
++	au_fclr_cpdown(args->flags, DIROPQ);
++	if (au_dbwh(dentry) == bdst)
++		au_fset_cpdown(args->flags, WHED);
++	if (!au_ftest_cpdown(args->flags, PARENT_OPQ) && bopq <= bdst)
++		au_fset_cpdown(args->flags, PARENT_OPQ);
++	parent_opq = (au_ftest_cpdown(args->flags, PARENT_OPQ)
++		      && args->parent == dentry);
++	h_inode = h_path.dentry->d_inode;
++	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++	if (au_ftest_cpdown(args->flags, WHED)) {
++		err = au_cpdown_dir_opq(dentry, bdst, args);
++		if (unlikely(err)) {
++			mutex_unlock(&h_inode->i_mutex);
++			goto out_dir;
++		}
++	}
++
++	err = au_cpdown_attr(&h_path, au_h_dptr(dentry, bstart));
++	mutex_unlock(&h_inode->i_mutex);
++	if (unlikely(err))
++		goto out_opq;
++
++	if (au_ftest_cpdown(args->flags, WHED)) {
++		err = au_cpdown_dir_wh(dentry, h_parent, dir, bdst);
++		if (unlikely(err))
++			goto out_opq;
++	}
++
++	inode = dentry->d_inode;
++	if (au_ibend(inode) < bdst)
++		au_set_ibend(inode, bdst);
++	au_set_h_iptr(inode, bdst, au_igrab(h_inode),
++		      au_hi_flags(inode, /*isdir*/1));
++	goto out; /* success */
++
++	/* revert */
++ out_opq:
++	if (au_ftest_cpdown(args->flags, DIROPQ)) {
++		mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++		rerr = au_diropq_remove(dentry, bdst);
++		mutex_unlock(&h_inode->i_mutex);
++		if (unlikely(rerr)) {
++			AuIOErr("failed removing diropq for %.*s b%d (%d)\n",
++				AuDLNPair(dentry), bdst, rerr);
++			err = -EIO;
++			goto out;
++		}
++	}
++ out_dir:
++	if (au_ftest_cpdown(args->flags, MADE_DIR)) {
++		rerr = vfsub_sio_rmdir(au_h_iptr(dir, bdst), &h_path);
++		if (unlikely(rerr)) {
++			AuIOErr("failed removing %.*s b%d (%d)\n",
++				AuDLNPair(dentry), bdst, rerr);
++			err = -EIO;
++		}
++	}
++ out_put:
++	au_set_h_dptr(dentry, bdst, NULL);
++	if (au_dbend(dentry) == bdst)
++		au_update_dbend(dentry);
++ out:
++	dput(parent);
++	return err;
++}
++
++int au_cpdown_dirs(struct dentry *dentry, aufs_bindex_t bdst)
++{
++	int err;
++	struct au_cpdown_dir_args args = {
++		.parent	= dget_parent(dentry),
++		.flags	= 0
++	};
++
++	err = au_cp_dirs(dentry, bdst, au_cpdown_dir, &args);
++	dput(args.parent);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* policies for create */
++
++static int au_wbr_bu(struct super_block *sb, aufs_bindex_t bindex)
++{
++	for (; bindex >= 0; bindex--)
++		if (!au_br_rdonly(au_sbr(sb, bindex)))
++			return bindex;
++	return -EROFS;
++}
++
++/* top down parent */
++static int au_wbr_create_tdp(struct dentry *dentry, int isdir __maybe_unused)
++{
++	int err;
++	aufs_bindex_t bstart, bindex;
++	struct super_block *sb;
++	struct dentry *parent, *h_parent;
++
++	sb = dentry->d_sb;
++	bstart = au_dbstart(dentry);
++	err = bstart;
++	if (!au_br_rdonly(au_sbr(sb, bstart)))
++		goto out;
++
++	err = -EROFS;
++	parent = dget_parent(dentry);
++	for (bindex = au_dbstart(parent); bindex < bstart; bindex++) {
++		h_parent = au_h_dptr(parent, bindex);
++		if (!h_parent || !h_parent->d_inode)
++			continue;
++
++		if (!au_br_rdonly(au_sbr(sb, bindex))) {
++			err = bindex;
++			break;
++		}
++	}
++	dput(parent);
++
++	/* bottom up here */
++	if (unlikely(err < 0))
++		err = au_wbr_bu(sb, bstart - 1);
++
++ out:
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* an exception for the policy other than tdp */
++static int au_wbr_create_exp(struct dentry *dentry)
++{
++	int err;
++	aufs_bindex_t bwh, bdiropq;
++	struct dentry *parent;
++
++	err = -1;
++	bwh = au_dbwh(dentry);
++	parent = dget_parent(dentry);
++	bdiropq = au_dbdiropq(parent);
++	if (bwh >= 0) {
++		if (bdiropq >= 0)
++			err = min(bdiropq, bwh);
++		else
++			err = bwh;
++		AuDbg("%d\n", err);
++	} else if (bdiropq >= 0) {
++		err = bdiropq;
++		AuDbg("%d\n", err);
++	}
++	dput(parent);
++
++	if (err >= 0 && au_br_rdonly(au_sbr(dentry->d_sb, err)))
++		err = -1;
++
++	AuDbg("%d\n", err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* round robin */
++static int au_wbr_create_init_rr(struct super_block *sb)
++{
++	int err;
++
++	err = au_wbr_bu(sb, au_sbend(sb));
++	atomic_set(&au_sbi(sb)->si_wbr_rr_next, -err); /* less important */
++
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++static int au_wbr_create_rr(struct dentry *dentry, int isdir)
++{
++	int err, nbr;
++	unsigned int u;
++	aufs_bindex_t bindex, bend;
++	struct super_block *sb;
++	atomic_t *next;
++
++	err = au_wbr_create_exp(dentry);
++	if (err >= 0)
++		goto out;
++
++	sb = dentry->d_sb;
++	next = &au_sbi(sb)->si_wbr_rr_next;
++	bend = au_sbend(sb);
++	nbr = bend + 1;
++	for (bindex = 0; bindex <= bend; bindex++) {
++		if (!isdir) {
++			err = atomic_dec_return(next) + 1;
++			/* modulo for 0 is meaningless */
++			if (unlikely(!err))
++				err = atomic_dec_return(next) + 1;
++		} else
++			err = atomic_read(next);
++		AuDbg("%d\n", err);
++		u = err;
++		err = u % nbr;
++		AuDbg("%d\n", err);
++		if (!au_br_rdonly(au_sbr(sb, err)))
++			break;
++		err = -EROFS;
++	}
++
++ out:
++	AuDbg("%d\n", err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* most free space */
++static void au_mfs(struct dentry *dentry)
++{
++	struct super_block *sb;
++	struct au_branch *br;
++	struct au_wbr_mfs *mfs;
++	aufs_bindex_t bindex, bend;
++	int err;
++	unsigned long long b, bavail;
++	/* reduce the stack usage */
++	struct kstatfs *st;
++
++	st = kmalloc(sizeof(*st), GFP_NOFS);
++	if (unlikely(!st)) {
++		AuWarn1("failed updating mfs(%d), ignored\n", -ENOMEM);
++		return;
++	}
++
++	bavail = 0;
++	sb = dentry->d_sb;
++	mfs = &au_sbi(sb)->si_wbr_mfs;
++	mfs->mfs_bindex = -EROFS;
++	mfs->mfsrr_bytes = 0;
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		if (au_br_rdonly(br))
++			continue;
++
++		/* sb->s_root for NFS is unreliable */
++		err = vfs_statfs(br->br_mnt->mnt_root, st);
++		if (unlikely(err)) {
++			AuWarn1("failed statfs, b%d, %d\n", bindex, err);
++			continue;
++		}
++
++		/* when the available size is equal, select the lower one */
++		BUILD_BUG_ON(sizeof(b) < sizeof(st->f_bavail)
++			     || sizeof(b) < sizeof(st->f_bsize));
++		b = st->f_bavail * st->f_bsize;
++		br->br_wbr->wbr_bytes = b;
++		if (b >= bavail) {
++			bavail = b;
++			mfs->mfs_bindex = bindex;
++			mfs->mfs_jiffy = jiffies;
++		}
++	}
++
++	mfs->mfsrr_bytes = bavail;
++	AuDbg("b%d\n", mfs->mfs_bindex);
++	kfree(st);
++}
++
++static int au_wbr_create_mfs(struct dentry *dentry, int isdir __maybe_unused)
++{
++	int err;
++	struct super_block *sb;
++	struct au_wbr_mfs *mfs;
++
++	err = au_wbr_create_exp(dentry);
++	if (err >= 0)
++		goto out;
++
++	sb = dentry->d_sb;
++	mfs = &au_sbi(sb)->si_wbr_mfs;
++	mutex_lock(&mfs->mfs_lock);
++	if (time_after(jiffies, mfs->mfs_jiffy + mfs->mfs_expire)
++	    || mfs->mfs_bindex < 0
++	    || au_br_rdonly(au_sbr(sb, mfs->mfs_bindex)))
++		au_mfs(dentry);
++	mutex_unlock(&mfs->mfs_lock);
++	err = mfs->mfs_bindex;
++
++ out:
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++static int au_wbr_create_init_mfs(struct super_block *sb)
++{
++	struct au_wbr_mfs *mfs;
++
++	mfs = &au_sbi(sb)->si_wbr_mfs;
++	mutex_init(&mfs->mfs_lock);
++	mfs->mfs_jiffy = 0;
++	mfs->mfs_bindex = -EROFS;
++
++	return 0;
++}
++
++static int au_wbr_create_fin_mfs(struct super_block *sb __maybe_unused)
++{
++	mutex_destroy(&au_sbi(sb)->si_wbr_mfs.mfs_lock);
++	return 0;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* most free space and then round robin */
++static int au_wbr_create_mfsrr(struct dentry *dentry, int isdir)
++{
++	int err;
++	struct au_wbr_mfs *mfs;
++
++	err = au_wbr_create_mfs(dentry, isdir);
++	if (err >= 0) {
++		mfs = &au_sbi(dentry->d_sb)->si_wbr_mfs;
++		if (mfs->mfsrr_bytes < mfs->mfsrr_watermark)
++			err = au_wbr_create_rr(dentry, isdir);
++	}
++
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++static int au_wbr_create_init_mfsrr(struct super_block *sb)
++{
++	int err;
++
++	au_wbr_create_init_mfs(sb); /* ignore */
++	err = au_wbr_create_init_rr(sb);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* top down parent and most free space */
++static int au_wbr_create_pmfs(struct dentry *dentry, int isdir)
++{
++	int err, e2;
++	unsigned long long b;
++	aufs_bindex_t bindex, bstart, bend;
++	struct super_block *sb;
++	struct dentry *parent, *h_parent;
++	struct au_branch *br;
++
++	err = au_wbr_create_tdp(dentry, isdir);
++	if (unlikely(err < 0))
++		goto out;
++	parent = dget_parent(dentry);
++	bstart = au_dbstart(parent);
++	bend = au_dbtaildir(parent);
++	if (bstart == bend)
++		goto out_parent; /* success */
++
++	e2 = au_wbr_create_mfs(dentry, isdir);
++	if (e2 < 0)
++		goto out_parent; /* success */
++
++	/* when the available size is equal, select upper one */
++	sb = dentry->d_sb;
++	br = au_sbr(sb, err);
++	b = br->br_wbr->wbr_bytes;
++	AuDbg("b%d, %llu\n", err, b);
++
++	for (bindex = bstart; bindex <= bend; bindex++) {
++		h_parent = au_h_dptr(parent, bindex);
++		if (!h_parent || !h_parent->d_inode)
++			continue;
++
++		br = au_sbr(sb, bindex);
++		if (!au_br_rdonly(br) && br->br_wbr->wbr_bytes > b) {
++			b = br->br_wbr->wbr_bytes;
++			err = bindex;
++			AuDbg("b%d, %llu\n", err, b);
++		}
++	}
++
++ out_parent:
++	dput(parent);
++ out:
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* policies for copyup */
++
++/* top down parent */
++static int au_wbr_copyup_tdp(struct dentry *dentry)
++{
++	return au_wbr_create_tdp(dentry, /*isdir, anything is ok*/0);
++}
++
++/* bottom up parent */
++static int au_wbr_copyup_bup(struct dentry *dentry)
++{
++	int err;
++	aufs_bindex_t bindex, bstart;
++	struct dentry *parent, *h_parent;
++	struct super_block *sb;
++
++	err = -EROFS;
++	sb = dentry->d_sb;
++	parent = dget_parent(dentry);
++	bstart = au_dbstart(parent);
++	for (bindex = au_dbstart(dentry); bindex >= bstart; bindex--) {
++		h_parent = au_h_dptr(parent, bindex);
++		if (!h_parent || !h_parent->d_inode)
++			continue;
++
++		if (!au_br_rdonly(au_sbr(sb, bindex))) {
++			err = bindex;
++			break;
++		}
++	}
++	dput(parent);
++
++	/* bottom up here */
++	if (unlikely(err < 0))
++		err = au_wbr_bu(sb, bstart - 1);
++
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++/* bottom up */
++static int au_wbr_copyup_bu(struct dentry *dentry)
++{
++	int err;
++
++	err = au_wbr_bu(dentry->d_sb, au_dbstart(dentry));
++
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct au_wbr_copyup_operations au_wbr_copyup_ops[] = {
++	[AuWbrCopyup_TDP] = {
++		.copyup	= au_wbr_copyup_tdp
++	},
++	[AuWbrCopyup_BUP] = {
++		.copyup	= au_wbr_copyup_bup
++	},
++	[AuWbrCopyup_BU] = {
++		.copyup	= au_wbr_copyup_bu
++	}
++};
++
++struct au_wbr_create_operations au_wbr_create_ops[] = {
++	[AuWbrCreate_TDP] = {
++		.create	= au_wbr_create_tdp
++	},
++	[AuWbrCreate_RR] = {
++		.create	= au_wbr_create_rr,
++		.init	= au_wbr_create_init_rr
++	},
++	[AuWbrCreate_MFS] = {
++		.create	= au_wbr_create_mfs,
++		.init	= au_wbr_create_init_mfs,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_MFSV] = {
++		.create	= au_wbr_create_mfs,
++		.init	= au_wbr_create_init_mfs,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_MFSRR] = {
++		.create	= au_wbr_create_mfsrr,
++		.init	= au_wbr_create_init_mfsrr,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_MFSRRV] = {
++		.create	= au_wbr_create_mfsrr,
++		.init	= au_wbr_create_init_mfsrr,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_PMFS] = {
++		.create	= au_wbr_create_pmfs,
++		.init	= au_wbr_create_init_mfs,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_PMFSV] = {
++		.create	= au_wbr_create_pmfs,
++		.init	= au_wbr_create_init_mfs,
++		.fin	= au_wbr_create_fin_mfs
++	}
++};
+diff -uNr test/fs/aufs/whout.c aufs2-standalone/fs/aufs/whout.c
+--- test/fs/aufs/whout.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/whout.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,1010 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * whiteout for logical deletion and opaque directory
++ */
++
++#include <linux/fs.h>
++#include "aufs.h"
++
++#define WH_MASK			S_IRUGO
++
++/*
++ * If a directory contains this file, then it is opaque.  We start with the
++ * .wh. flag so that it is blocked by lookup.
++ */
++static struct qstr diropq_name = {
++	.name = AUFS_WH_DIROPQ,
++	.len = sizeof(AUFS_WH_DIROPQ) - 1
++};
++
++/*
++ * generate whiteout name, which is NOT terminated by NULL.
++ * @name: original d_name.name
++ * @len: original d_name.len
++ * @wh: whiteout qstr
++ * returns zero when succeeds, otherwise error.
++ * succeeded value as wh->name should be freed by kfree().
++ */
++int au_wh_name_alloc(struct qstr *wh, const struct qstr *name)
++{
++	char *p;
++
++	if (unlikely(name->len > PATH_MAX - AUFS_WH_PFX_LEN))
++		return -ENAMETOOLONG;
++
++	wh->len = name->len + AUFS_WH_PFX_LEN;
++	p = kmalloc(wh->len, GFP_NOFS);
++	wh->name = p;
++	if (p) {
++		memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
++		memcpy(p + AUFS_WH_PFX_LEN, name->name, name->len);
++		/* smp_mb(); */
++		return 0;
++	}
++	return -ENOMEM;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * test if the @wh_name exists under @h_parent.
++ * @try_sio specifies the necessary of super-io.
++ */
++int au_wh_test(struct dentry *h_parent, struct qstr *wh_name,
++	       struct au_branch *br, int try_sio)
++{
++	int err;
++	struct dentry *wh_dentry;
++	struct inode *h_dir;
++
++	h_dir = h_parent->d_inode;
++	if (!try_sio)
++		wh_dentry = au_lkup_one(wh_name, h_parent, br, /*nd*/NULL);
++	else
++		wh_dentry = au_sio_lkup_one(wh_name, h_parent, br);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out;
++
++	err = 0;
++	if (!wh_dentry->d_inode)
++		goto out_wh; /* success */
++
++	err = 1;
++	if (S_ISREG(wh_dentry->d_inode->i_mode))
++		goto out_wh; /* success */
++
++	err = -EIO;
++	AuIOErr("%.*s Invalid whiteout entry type 0%o.\n",
++		AuDLNPair(wh_dentry), wh_dentry->d_inode->i_mode);
++
++ out_wh:
++	dput(wh_dentry);
++ out:
++	return err;
++}
++
++/*
++ * test if the @h_dentry sets opaque or not.
++ */
++int au_diropq_test(struct dentry *h_dentry, struct au_branch *br)
++{
++	int err;
++	struct inode *h_dir;
++
++	h_dir = h_dentry->d_inode;
++	err = au_wh_test(h_dentry, &diropq_name, br,
++			 au_test_h_perm_sio(h_dir, MAY_EXEC));
++	return err;
++}
++
++/*
++ * returns a negative dentry whose name is unique and temporary.
++ */
++struct dentry *au_whtmp_lkup(struct dentry *h_parent, struct au_branch *br,
++			     struct qstr *prefix)
++{
++#define HEX_LEN	4
++	struct dentry *dentry;
++	int i;
++	char defname[AUFS_WH_PFX_LEN * 2 + DNAME_INLINE_LEN_MIN + 1
++		     + HEX_LEN + 1], *name, *p;
++	static unsigned short cnt;
++	struct qstr qs;
++
++	name = defname;
++	qs.len = sizeof(defname) - DNAME_INLINE_LEN_MIN + prefix->len - 1;
++	if (unlikely(prefix->len > DNAME_INLINE_LEN_MIN)) {
++		dentry = ERR_PTR(-ENAMETOOLONG);
++		if (unlikely(qs.len >= PATH_MAX))
++			goto out;
++		dentry = ERR_PTR(-ENOMEM);
++		name = kmalloc(qs.len + 1, GFP_NOFS);
++		if (unlikely(!name))
++			goto out;
++	}
++
++	/* doubly whiteout-ed */
++	memcpy(name, AUFS_WH_PFX AUFS_WH_PFX, AUFS_WH_PFX_LEN * 2);
++	p = name + AUFS_WH_PFX_LEN * 2;
++	memcpy(p, prefix->name, prefix->len);
++	p += prefix->len;
++	*p++ = '.';
++	AuDebugOn(name + qs.len + 1 - p <= HEX_LEN);
++
++	qs.name = name;
++	for (i = 0; i < 3; i++) {
++		sprintf(p, "%.*d", HEX_LEN, cnt++);
++		dentry = au_sio_lkup_one(&qs, h_parent, br);
++		if (IS_ERR(dentry) || !dentry->d_inode)
++			goto out_name;
++		dput(dentry);
++	}
++	/* AuWarn("could not get random name\n"); */
++	dentry = ERR_PTR(-EEXIST);
++	AuDbg("%.*s\n", AuLNPair(&qs));
++	BUG();
++
++ out_name:
++	if (name != defname)
++		kfree(name);
++ out:
++	return dentry;
++#undef HEX_LEN
++}
++
++/*
++ * rename the @h_dentry on @br to the whiteouted temporary name.
++ */
++int au_whtmp_ren(struct dentry *h_dentry, struct au_branch *br)
++{
++	int err;
++	struct path h_path = {
++		.mnt = br->br_mnt
++	};
++	struct inode *h_dir;
++	struct dentry *h_parent;
++
++	h_parent = h_dentry->d_parent; /* dir inode is locked */
++	h_dir = h_parent->d_inode;
++	IMustLock(h_dir);
++
++	h_path.dentry = au_whtmp_lkup(h_parent, br, &h_dentry->d_name);
++	err = PTR_ERR(h_path.dentry);
++	if (IS_ERR(h_path.dentry))
++		goto out;
++
++	/* under the same dir, no need to lock_rename() */
++	err = vfsub_rename(h_dir, h_dentry, h_dir, &h_path);
++	AuTraceErr(err);
++	dput(h_path.dentry);
++
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++/*
++ * functions for removing a whiteout
++ */
++
++static int do_unlink_wh(struct inode *h_dir, struct path *h_path)
++{
++	int force;
++
++	/*
++	 * forces superio when the dir has a sticky bit.
++	 * this may be a violation of unix fs semantics.
++	 */
++	force = (h_dir->i_mode & S_ISVTX)
++		&& h_path->dentry->d_inode->i_uid != current->fsuid;
++	return vfsub_unlink(h_dir, h_path, force);
++}
++
++int au_wh_unlink_dentry(struct inode *h_dir, struct path *h_path,
++			struct dentry *dentry)
++{
++	int err;
++
++	err = do_unlink_wh(h_dir, h_path);
++	if (!err && dentry)
++		au_set_dbwh(dentry, -1);
++
++	return err;
++}
++
++static int unlink_wh_name(struct dentry *h_parent, struct qstr *wh,
++			  struct au_branch *br)
++{
++	int err;
++	struct path h_path = {
++		.mnt = br->br_mnt
++	};
++
++	err = 0;
++	h_path.dentry = au_lkup_one(wh, h_parent, br, /*nd*/NULL);
++	if (IS_ERR(h_path.dentry))
++		err = PTR_ERR(h_path.dentry);
++	else {
++		if (h_path.dentry->d_inode
++		    && S_ISREG(h_path.dentry->d_inode->i_mode))
++			err = do_unlink_wh(h_parent->d_inode, &h_path);
++		dput(h_path.dentry);
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++/*
++ * initialize/clean whiteout for a branch
++ */
++
++static void au_wh_clean(struct inode *h_dir, struct path *whpath,
++			const int isdir)
++{
++	int err;
++
++	if (!whpath->dentry->d_inode)
++		return;
++
++	err = mnt_want_write(whpath->mnt);
++	if (!err) {
++		if (isdir)
++			err = vfsub_rmdir(h_dir, whpath);
++		else
++			err = vfsub_unlink(h_dir, whpath, /*force*/0);
++		mnt_drop_write(whpath->mnt);
++	}
++	if (unlikely(err))
++		AuWarn("failed removing %.*s (%d), ignored.\n",
++		       AuDLNPair(whpath->dentry), err);
++}
++
++static int test_linkable(struct dentry *h_root)
++{
++	struct inode *h_dir = h_root->d_inode;
++
++	if (h_dir->i_op && h_dir->i_op->link)
++		return 0;
++
++	AuErr("%.*s (%s) doesn't support link(2), use noplink and rw+nolwh\n",
++	      AuDLNPair(h_root), au_sbtype(h_root->d_sb));
++	return -ENOSYS;
++}
++
++/* todo: should this mkdir be done in /sbin/mount.aufs helper? */
++static int au_whdir(struct inode *h_dir, struct path *path)
++{
++	int err;
++
++	err = -EEXIST;
++	if (!path->dentry->d_inode) {
++		int mode = S_IRWXU;
++
++		if (au_test_nfs(path->dentry->d_sb))
++			mode |= S_IXUGO;
++		err = mnt_want_write(path->mnt);
++		if (!err) {
++			err = vfsub_mkdir(h_dir, path, mode);
++			mnt_drop_write(path->mnt);
++		}
++	} else if (S_ISDIR(path->dentry->d_inode->i_mode))
++		err = 0;
++	else
++		AuErr("unknown %.*s exists\n", AuDLNPair(path->dentry));
++
++	return err;
++}
++
++struct au_wh_base {
++	const struct qstr *name;
++	struct dentry *dentry;
++};
++
++static void au_wh_init_ro(struct inode *h_dir, struct au_wh_base base[],
++			  struct path *h_path)
++{
++	h_path->dentry = base[AuBrWh_BASE].dentry;
++	au_wh_clean(h_dir, h_path, /*isdir*/0);
++	h_path->dentry = base[AuBrWh_PLINK].dentry;
++	au_wh_clean(h_dir, h_path, /*isdir*/1);
++	h_path->dentry = base[AuBrWh_ORPH].dentry;
++	au_wh_clean(h_dir, h_path, /*isdir*/1);
++}
++
++/*
++ * returns tri-state,
++ * minus: error, caller should print the mesage
++ * zero: succuess
++ * plus: error, caller should NOT print the mesage
++ */
++static int au_wh_init_rw_nolink(struct dentry *h_root, struct au_wbr *wbr,
++				int do_plink, struct au_wh_base base[],
++				struct path *h_path)
++{
++	int err;
++	struct inode *h_dir;
++
++	h_dir = h_root->d_inode;
++	h_path->dentry = base[AuBrWh_BASE].dentry;
++	au_wh_clean(h_dir, h_path, /*isdir*/0);
++	h_path->dentry = base[AuBrWh_PLINK].dentry;
++	if (do_plink) {
++		err = test_linkable(h_root);
++		if (unlikely(err)) {
++			err = 1;
++			goto out;
++		}
++
++		err = au_whdir(h_dir, h_path);
++		if (unlikely(err))
++			goto out;
++		wbr->wbr_plink = dget(base[AuBrWh_PLINK].dentry);
++	} else
++		au_wh_clean(h_dir, h_path, /*isdir*/1);
++	h_path->dentry = base[AuBrWh_ORPH].dentry;
++	err = au_whdir(h_dir, h_path);
++	if (unlikely(err))
++		goto out;
++	wbr->wbr_orph = dget(base[AuBrWh_ORPH].dentry);
++
++ out:
++	return err;
++}
++
++/*
++ * for the moment, aufs supports the branch filesystem which does not support
++ * link(2). testing on FAT which does not support i_op->setattr() fully either,
++ * copyup failed. finally, such filesystem will not be used as the writable
++ * branch.
++ *
++ * returns tri-state, see above.
++ */
++static int au_wh_init_rw(struct dentry *h_root, struct au_wbr *wbr,
++			 int do_plink, struct au_wh_base base[],
++			 struct path *h_path)
++{
++	int err;
++	struct inode *h_dir;
++
++	err = test_linkable(h_root);
++	if (unlikely(err)) {
++		err = 1;
++		goto out;
++	}
++
++	/*
++	 * todo: should this create be done in /sbin/mount.aufs helper?
++	 */
++	err = -EEXIST;
++	h_dir = h_root->d_inode;
++	if (!base[AuBrWh_BASE].dentry->d_inode) {
++		err = mnt_want_write(h_path->mnt);
++		if (!err) {
++			h_path->dentry = base[AuBrWh_BASE].dentry;
++			err = vfsub_create(h_dir, h_path, WH_MASK);
++			mnt_drop_write(h_path->mnt);
++		}
++	} else if (S_ISREG(base[AuBrWh_BASE].dentry->d_inode->i_mode))
++		err = 0;
++	else
++		AuErr("unknown %.*s/%.*s exists\n",
++		      AuDLNPair(h_root), AuDLNPair(base[AuBrWh_BASE].dentry));
++	if (unlikely(err))
++		goto out;
++
++	h_path->dentry = base[AuBrWh_PLINK].dentry;
++	if (do_plink) {
++		err = au_whdir(h_dir, h_path);
++		if (unlikely(err))
++			goto out;
++		wbr->wbr_plink = dget(base[AuBrWh_PLINK].dentry);
++	} else
++		au_wh_clean(h_dir, h_path, /*isdir*/1);
++	wbr->wbr_whbase = dget(base[AuBrWh_BASE].dentry);
++
++	h_path->dentry = base[AuBrWh_ORPH].dentry;
++	err = au_whdir(h_dir, h_path);
++	if (unlikely(err))
++		goto out;
++	wbr->wbr_orph = dget(base[AuBrWh_ORPH].dentry);
++
++ out:
++	return err;
++}
++
++/*
++ * initialize the whiteout base file/dir for @br.
++ */
++int au_wh_init(struct dentry *h_root, struct au_branch *br,
++	       struct super_block *sb)
++{
++	int err, i;
++	const unsigned char do_plink
++		= !!au_opt_test(au_mntflags(sb), PLINK);
++	struct path path = {
++		.mnt = br->br_mnt
++	};
++	struct inode *h_dir;
++	struct au_wbr *wbr = br->br_wbr;
++	static const struct qstr base_name[] = {
++		[AuBrWh_BASE] = {
++			.name	= AUFS_BASE_NAME,
++			.len	= sizeof(AUFS_BASE_NAME) - 1
++		},
++		[AuBrWh_PLINK] = {
++			.name	= AUFS_PLINKDIR_NAME,
++			.len	= sizeof(AUFS_PLINKDIR_NAME) - 1
++		},
++		[AuBrWh_ORPH] = {
++			.name	= AUFS_ORPHDIR_NAME,
++			.len	= sizeof(AUFS_ORPHDIR_NAME) - 1
++		}
++	};
++	struct au_wh_base base[] = {
++		[AuBrWh_BASE] = {
++			.name	= base_name + AuBrWh_BASE,
++			.dentry	= NULL
++		},
++		[AuBrWh_PLINK] = {
++			.name	= base_name + AuBrWh_PLINK,
++			.dentry	= NULL
++		},
++		[AuBrWh_ORPH] = {
++			.name	= base_name + AuBrWh_ORPH,
++			.dentry	= NULL
++		}
++	};
++
++
++	h_dir = h_root->d_inode;
++	for (i = 0; i < AuBrWh_Last; i++) {
++		/* doubly whiteouted */
++		struct dentry *d;
++
++		d = au_wh_lkup(h_root, (void *)base[i].name, br);
++		err = PTR_ERR(d);
++		if (IS_ERR(d))
++			goto out;
++
++		base[i].dentry = d;
++		AuDebugOn(wbr
++			  && wbr->wbr_wh[i]
++			  && wbr->wbr_wh[i] != base[i].dentry);
++	}
++
++	if (wbr)
++		for (i = 0; i < AuBrWh_Last; i++) {
++			dput(wbr->wbr_wh[i]);
++			wbr->wbr_wh[i] = NULL;
++		}
++
++	err = 0;
++
++	switch (br->br_perm) {
++	case AuBrPerm_RO:
++	case AuBrPerm_ROWH:
++	case AuBrPerm_RR:
++	case AuBrPerm_RRWH:
++		au_wh_init_ro(h_dir, base, &path);
++		break;
++
++	case AuBrPerm_RWNoLinkWH:
++		err = au_wh_init_rw_nolink(h_root, wbr, do_plink, base, &path);
++		if (err > 0)
++			goto out;
++		else if (err)
++			goto out_err;
++		break;
++
++	case AuBrPerm_RW:
++		err = au_wh_init_rw(h_root, wbr, do_plink, base, &path);
++		if (err > 0)
++			goto out;
++		else if (err)
++			goto out_err;
++		break;
++
++	default:
++		BUG();
++	}
++	goto out; /* success */
++
++ out_err:
++	AuErr("an error(%d) on the writable branch %.*s(%s)\n",
++	      err, AuDLNPair(h_root), au_sbtype(h_root->d_sb));
++ out:
++	for (i = 0; i < AuBrWh_Last; i++)
++		dput(base[i].dentry);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++/*
++ * whiteouts are all hard-linked usually.
++ * when its link count reaches a ceiling, we create a new whiteout base
++ * asynchronously.
++ */
++
++struct reinit_br_wh {
++	struct super_block *sb;
++	struct au_branch *br;
++};
++
++static void reinit_br_wh(void *arg)
++{
++	int err;
++	aufs_bindex_t bindex;
++	struct path h_path;
++	struct reinit_br_wh *a = arg;
++	struct au_wbr *wbr;
++	struct inode *dir;
++	struct dentry *h_root;
++	struct au_hinode *hdir;
++
++	err = 0;
++	wbr = a->br->br_wbr;
++	/* big aufs lock */
++	si_noflush_write_lock(a->sb);
++	if (!au_br_writable(a->br->br_perm))
++		goto out;
++	bindex = au_br_index(a->sb, a->br->br_id);
++	if (unlikely(bindex < 0))
++		goto out;
++
++	dir = a->sb->s_root->d_inode;
++	/* ii_read_lock_parent(dir); */
++	hdir = au_hi(dir, bindex);
++	h_root = au_h_dptr(a->sb->s_root, bindex);
++
++	au_hin_imtx_lock_nested(hdir, AuLsc_I_PARENT);
++	wbr_wh_write_lock(wbr);
++	err = au_h_verify(wbr->wbr_whbase, au_opt_udba(a->sb), hdir->hi_inode,
++			  h_root, a->br);
++	if (!err) {
++		err = mnt_want_write(a->br->br_mnt);
++		if (!err) {
++			h_path.dentry = wbr->wbr_whbase;
++			h_path.mnt = a->br->br_mnt;
++			err = vfsub_unlink(hdir->hi_inode, &h_path, /*force*/0);
++			mnt_drop_write(a->br->br_mnt);
++		}
++	} else {
++		AuWarn("%.*s is moved, ignored\n", AuDLNPair(wbr->wbr_whbase));
++		err = 0;
++	}
++	dput(wbr->wbr_whbase);
++	wbr->wbr_whbase = NULL;
++	if (!err)
++		err = au_wh_init(h_root, a->br, a->sb);
++	wbr_wh_write_unlock(wbr);
++	au_hin_imtx_unlock(hdir);
++	/* ii_read_unlock(dir); */
++
++ out:
++	if (wbr)
++		atomic_dec(&wbr->wbr_wh_running);
++	atomic_dec(&a->br->br_count);
++	au_nwt_done(&au_sbi(a->sb)->si_nowait);
++	si_write_unlock(a->sb);
++	kfree(arg);
++	if (unlikely(err))
++		AuIOErr("err %d\n", err);
++}
++
++static void kick_reinit_br_wh(struct super_block *sb, struct au_branch *br)
++{
++	int do_dec, wkq_err;
++	struct reinit_br_wh *arg;
++
++	do_dec = 1;
++	if (atomic_inc_return(&br->br_wbr->wbr_wh_running) != 1)
++		goto out;
++
++	/* ignore ENOMEM */
++	arg = kmalloc(sizeof(*arg), GFP_NOFS);
++	if (arg) {
++		/*
++		 * dec(wh_running), kfree(arg) and dec(br_count)
++		 * in reinit function
++		 */
++		arg->sb = sb;
++		arg->br = br;
++		atomic_inc(&br->br_count);
++		wkq_err = au_wkq_nowait(reinit_br_wh, arg, sb);
++		if (unlikely(wkq_err)) {
++			atomic_dec(&br->br_wbr->wbr_wh_running);
++			atomic_dec(&br->br_count);
++			kfree(arg);
++		}
++		do_dec = 0;
++	}
++
++ out:
++	if (do_dec)
++		atomic_dec(&br->br_wbr->wbr_wh_running);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * create the whiteout @wh.
++ */
++static int link_or_create_wh(struct super_block *sb, aufs_bindex_t bindex,
++			     struct dentry *wh)
++{
++	int err;
++	struct path h_path = {
++		.dentry = wh
++	};
++	struct au_branch *br;
++	struct au_wbr *wbr;
++	struct dentry *h_parent;
++	struct inode *h_dir;
++
++	h_parent = wh->d_parent; /* dir inode is locked */
++	h_dir = h_parent->d_inode;
++	IMustLock(h_dir);
++
++	br = au_sbr(sb, bindex);
++	h_path.mnt = br->br_mnt;
++	wbr = br->br_wbr;
++	wbr_wh_read_lock(wbr);
++	if (wbr->wbr_whbase) {
++		err = vfsub_link(wbr->wbr_whbase, h_dir, &h_path);
++		if (!err || err != -EMLINK)
++			goto out;
++
++		/* link count full. re-initialize br_whbase. */
++		kick_reinit_br_wh(sb, br);
++	}
++
++	/* return this error in this context */
++	err = vfsub_create(h_dir, &h_path, WH_MASK);
++
++ out:
++	wbr_wh_read_unlock(wbr);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * create or remove the diropq.
++ */
++static struct dentry *do_diropq(struct dentry *dentry, aufs_bindex_t bindex,
++				unsigned int flags)
++{
++	struct dentry *opq_dentry, *h_dentry;
++	struct super_block *sb;
++	struct au_branch *br;
++	int err;
++
++	sb = dentry->d_sb;
++	br = au_sbr(sb, bindex);
++	h_dentry = au_h_dptr(dentry, bindex);
++	opq_dentry = au_lkup_one(&diropq_name, h_dentry, br, /*nd*/NULL);
++	if (IS_ERR(opq_dentry))
++		goto out;
++
++	if (au_ftest_diropq(flags, CREATE)) {
++		err = link_or_create_wh(sb, bindex, opq_dentry);
++		if (!err) {
++			au_set_dbdiropq(dentry, bindex);
++			goto out; /* success */
++		}
++	} else {
++		struct path tmp = {
++			.dentry = opq_dentry,
++			.mnt	= br->br_mnt
++		};
++		err = do_unlink_wh(au_h_iptr(dentry->d_inode, bindex), &tmp);
++		if (!err)
++			au_set_dbdiropq(dentry, -1);
++	}
++	dput(opq_dentry);
++	opq_dentry = ERR_PTR(err);
++
++ out:
++	return opq_dentry;
++}
++
++struct do_diropq_args {
++	struct dentry **errp;
++	struct dentry *dentry;
++	aufs_bindex_t bindex;
++	unsigned int flags;
++};
++
++static void call_do_diropq(void *args)
++{
++	struct do_diropq_args *a = args;
++	*a->errp = do_diropq(a->dentry, a->bindex, a->flags);
++}
++
++struct dentry *au_diropq_sio(struct dentry *dentry, aufs_bindex_t bindex,
++			     unsigned int flags)
++{
++	struct dentry *diropq, *h_dentry;
++
++	h_dentry = au_h_dptr(dentry, bindex);
++	if (!au_test_h_perm_sio(h_dentry->d_inode, MAY_EXEC | MAY_WRITE))
++		diropq = do_diropq(dentry, bindex, flags);
++	else {
++		int wkq_err;
++		struct do_diropq_args args = {
++			.errp		= &diropq,
++			.dentry		= dentry,
++			.bindex		= bindex,
++			.flags		= flags
++		};
++
++		wkq_err = au_wkq_wait(call_do_diropq, &args);
++		if (unlikely(wkq_err))
++			diropq = ERR_PTR(wkq_err);
++	}
++
++	return diropq;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * lookup whiteout dentry.
++ * @h_parent: lower parent dentry which must exist and be locked
++ * @base_name: name of dentry which will be whiteouted
++ * returns dentry for whiteout.
++ */
++struct dentry *au_wh_lkup(struct dentry *h_parent, struct qstr *base_name,
++			  struct au_branch *br)
++{
++	int err;
++	struct qstr wh_name;
++	struct dentry *wh_dentry;
++
++	err = au_wh_name_alloc(&wh_name, base_name);
++	wh_dentry = ERR_PTR(err);
++	if (!err) {
++		wh_dentry = au_lkup_one(&wh_name, h_parent, br, /*nd*/NULL);
++		kfree(wh_name.name);
++	}
++	return wh_dentry;
++}
++
++/*
++ * link/create a whiteout for @dentry on @bindex.
++ */
++struct dentry *au_wh_create(struct dentry *dentry, aufs_bindex_t bindex,
++			    struct dentry *h_parent)
++{
++	struct dentry *wh_dentry;
++	struct super_block *sb;
++	int err;
++
++	sb = dentry->d_sb;
++	wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, au_sbr(sb, bindex));
++	if (!IS_ERR(wh_dentry) && !wh_dentry->d_inode) {
++		err = link_or_create_wh(sb, bindex, wh_dentry);
++		if (!err)
++			au_set_dbwh(dentry, bindex);
++		else {
++			dput(wh_dentry);
++			wh_dentry = ERR_PTR(err);
++		}
++	}
++
++	return wh_dentry;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* Delete all whiteouts in this directory on branch bindex. */
++static int del_wh_children(struct dentry *h_dentry, struct au_nhash *whlist,
++			   aufs_bindex_t bindex, struct au_branch *br)
++{
++	int err, i;
++	struct qstr wh_name;
++	char *p;
++	struct hlist_head *head;
++	struct au_vdir_wh *tpos;
++	struct hlist_node *pos;
++	struct au_vdir_destr *str;
++
++	err = -ENOMEM;
++	p = __getname();
++	wh_name.name = p;
++	if (unlikely(!wh_name.name))
++		goto out;
++
++	err = 0;
++	memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
++	p += AUFS_WH_PFX_LEN;
++	head = whlist->heads;
++	for (i = 0; !err && i < AuSize_NHASH; i++, head++) {
++		hlist_for_each_entry(tpos, pos, head, wh_hash) {
++			if (tpos->wh_bindex != bindex)
++				continue;
++
++			str = &tpos->wh_str;
++			if (str->len + AUFS_WH_PFX_LEN <= PATH_MAX) {
++				memcpy(p, str->name, str->len);
++				wh_name.len = AUFS_WH_PFX_LEN + str->len;
++				err = unlink_wh_name(h_dentry, &wh_name, br);
++				if (!err)
++					continue;
++				break;
++			}
++			AuIOErr("whiteout name too long %.*s\n",
++				str->len, str->name);
++			err = -EIO;
++			break;
++		}
++	}
++	__putname(wh_name.name);
++
++ out:
++	return err;
++}
++
++struct del_wh_children_args {
++	int *errp;
++	struct dentry *h_dentry;
++	struct au_nhash *whlist;
++	aufs_bindex_t bindex;
++	struct au_branch *br;
++};
++
++static void call_del_wh_children(void *args)
++{
++	struct del_wh_children_args *a = args;
++	*a->errp = del_wh_children(a->h_dentry, a->whlist, a->bindex, a->br);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * rmdir the whiteouted temporary named dir @h_dentry.
++ * @whlist: whiteouted children.
++ */
++int au_whtmp_rmdir(struct inode *dir, aufs_bindex_t bindex,
++		   struct dentry *wh_dentry, struct au_nhash *whlist)
++{
++	int err;
++	struct path h_tmp;
++	struct inode *wh_inode, *h_dir;
++	struct au_branch *br;
++
++	h_dir = wh_dentry->d_parent->d_inode; /* dir inode is locked */
++	IMustLock(h_dir);
++
++	br = au_sbr(dir->i_sb, bindex);
++	wh_inode = wh_dentry->d_inode;
++	mutex_lock_nested(&wh_inode->i_mutex, AuLsc_I_CHILD);
++
++	/*
++	 * someone else might change some whiteouts while we were sleeping.
++	 * it means this whlist may have an obsoleted entry.
++	 */
++	if (!au_test_h_perm_sio(wh_inode, MAY_EXEC | MAY_WRITE))
++		err = del_wh_children(wh_dentry, whlist, bindex, br);
++	else {
++		int wkq_err;
++		struct del_wh_children_args args = {
++			.errp		= &err,
++			.h_dentry	= wh_dentry,
++			.whlist		= whlist,
++			.bindex		= bindex,
++			.br		= br
++		};
++
++		wkq_err = au_wkq_wait(call_del_wh_children, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++	mutex_unlock(&wh_inode->i_mutex);
++
++	if (!err) {
++		h_tmp.dentry = wh_dentry;
++		h_tmp.mnt = br->br_mnt;
++		err = vfsub_rmdir(h_dir, &h_tmp);
++		/* d_drop(h_dentry); */
++	}
++
++	if (!err) {
++		if (au_ibstart(dir) == bindex) {
++			au_cpup_attr_timesizes(dir);
++			drop_nlink(dir);
++		}
++		return 0; /* success */
++	}
++
++	AuWarn("failed removing %.*s(%d), ignored\n",
++	       AuDLNPair(wh_dentry), err);
++	return err;
++}
++
++static void au_whtmp_rmdir_free_args(struct au_whtmp_rmdir_args *args)
++{
++	au_nhash_fin(&args->whlist);
++	dput(args->wh_dentry);
++	iput(args->dir);
++	kfree(args);
++}
++
++static void call_rmdir_whtmp(void *args)
++{
++	int err;
++	struct au_whtmp_rmdir_args *a = args;
++	struct super_block *sb;
++	struct dentry *h_parent;
++	struct inode *h_dir;
++	struct au_branch *br;
++	struct au_hinode *hdir;
++
++	/* rmdir by nfsd may cause deadlock with this i_mutex */
++	/* mutex_lock(&a->dir->i_mutex); */
++	sb = a->dir->i_sb;
++	si_noflush_read_lock(sb);
++	err = au_test_ro(sb, a->bindex, NULL);
++	if (unlikely(err))
++		goto out;
++
++	err = -EIO;
++	br = au_sbr(sb, a->bindex);
++	ii_write_lock_parent(a->dir);
++	h_parent = dget_parent(a->wh_dentry);
++	h_dir = h_parent->d_inode;
++	hdir = au_hi(a->dir, a->bindex);
++	au_hin_imtx_lock_nested(hdir, AuLsc_I_PARENT);
++	err = au_h_verify(a->wh_dentry, au_opt_udba(sb), h_dir, h_parent, br);
++	if (!err) {
++		err = mnt_want_write(br->br_mnt);
++		if (!err) {
++			err = au_whtmp_rmdir(a->dir, a->bindex, a->wh_dentry,
++					     &a->whlist);
++			mnt_drop_write(br->br_mnt);
++		}
++	}
++	au_hin_imtx_unlock(hdir);
++	dput(h_parent);
++	ii_write_unlock(a->dir);
++
++ out:
++	/* mutex_unlock(&a->dir->i_mutex); */
++	au_nwt_done(&au_sbi(sb)->si_nowait);
++	si_read_unlock(sb);
++	au_whtmp_rmdir_free_args(a);
++	if (unlikely(err))
++		AuIOErr("err %d\n", err);
++}
++
++void au_whtmp_kick_rmdir(struct inode *dir, aufs_bindex_t bindex,
++			 struct dentry *wh_dentry, struct au_nhash *whlist,
++			 struct au_whtmp_rmdir_args *args)
++{
++	int wkq_err;
++
++	IMustLock(dir);
++
++	/* all post-process will be done in do_rmdir_whtmp(). */
++	args->dir = au_igrab(dir);
++	args->bindex = bindex;
++	args->wh_dentry = dget(wh_dentry);
++	au_nhash_init(&args->whlist);
++	au_nhash_move(&args->whlist, whlist);
++	wkq_err = au_wkq_nowait(call_rmdir_whtmp, args, dir->i_sb);
++	if (unlikely(wkq_err)) {
++		AuWarn("rmdir error %.*s (%d), ignored\n",
++		       AuDLNPair(wh_dentry), wkq_err);
++		au_whtmp_rmdir_free_args(args);
++	}
++}
+diff -uNr test/fs/aufs/whout.h aufs2-standalone/fs/aufs/whout.h
+--- test/fs/aufs/whout.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/whout.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,78 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * whiteout for logical deletion and opaque directory
++ */
++
++#ifndef __AUFS_WHOUT_H__
++#define __AUFS_WHOUT_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/aufs_type.h>
++#include "dir.h"
++
++/* whout.c */
++int au_wh_name_alloc(struct qstr *wh, const struct qstr *name);
++struct au_branch;
++int au_wh_test(struct dentry *h_parent, struct qstr *wh_name,
++	       struct au_branch *br, int try_sio);
++int au_diropq_test(struct dentry *h_dentry, struct au_branch *br);
++struct dentry *au_whtmp_lkup(struct dentry *h_parent, struct au_branch *br,
++			     struct qstr *prefix);
++int au_whtmp_ren(struct dentry *h_dentry, struct au_branch *br);
++int au_wh_unlink_dentry(struct inode *h_dir, struct path *h_path,
++			struct dentry *dentry);
++int au_wh_init(struct dentry *h_parent, struct au_branch *br,
++	       struct super_block *sb);
++
++/* diropq flags */
++#define AuDiropq_CREATE	1
++#define au_ftest_diropq(flags, name)	((flags) & AuDiropq_##name)
++#define au_fset_diropq(flags, name)	{ (flags) |= AuDiropq_##name; }
++#define au_fclr_diropq(flags, name)	{ (flags) &= ~AuDiropq_##name; }
++
++struct dentry *au_diropq_sio(struct dentry *dentry, aufs_bindex_t bindex,
++			     unsigned int flags);
++struct dentry *au_wh_lkup(struct dentry *h_parent, struct qstr *base_name,
++			  struct au_branch *br);
++struct dentry *au_wh_create(struct dentry *dentry, aufs_bindex_t bindex,
++			    struct dentry *h_parent);
++
++/* real rmdir for the whiteout-ed dir */
++struct au_whtmp_rmdir_args {
++	struct inode *dir;
++	aufs_bindex_t bindex;
++	struct dentry *wh_dentry;
++	struct au_nhash whlist;
++};
++
++int au_whtmp_rmdir(struct inode *dir, aufs_bindex_t bindex,
++		   struct dentry *wh_dentry, struct au_nhash *whlist);
++void au_whtmp_kick_rmdir(struct inode *dir, aufs_bindex_t bindex,
++			 struct dentry *wh_dentry, struct au_nhash *whlist,
++			 struct au_whtmp_rmdir_args *args);
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct dentry *au_diropq_create(struct dentry *dentry,
++					      aufs_bindex_t bindex)
++{
++	return au_diropq_sio(dentry, bindex, AuDiropq_CREATE);
++}
++
++static inline int au_diropq_remove(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	return PTR_ERR(au_diropq_sio(dentry, bindex, !AuDiropq_CREATE));
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_WHOUT_H__ */
+diff -uNr test/fs/aufs/wkq.c aufs2-standalone/fs/aufs/wkq.c
+--- test/fs/aufs/wkq.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/wkq.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,249 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * workqueue for asynchronous/super-io operations
++ * todo: try new dredential scheme
++ */
++
++#include "aufs.h"
++
++/* internal workqueue named AUFS_WKQ_NAME */
++static struct au_wkq {
++	struct workqueue_struct	*q;
++
++	/* balancing */
++	atomic_t		busy;
++} *au_wkq;
++
++struct au_wkinfo {
++	struct work_struct wk;
++	struct super_block *sb;
++
++	unsigned int flags; /* see wkq.h */
++
++	au_wkq_func_t func;
++	void *args;
++
++	atomic_t *busyp;
++	struct completion *comp;
++};
++
++/* ---------------------------------------------------------------------- */
++
++static int enqueue(struct au_wkq *wkq, struct au_wkinfo *wkinfo)
++{
++	wkinfo->busyp = &wkq->busy;
++	if (au_ftest_wkq(wkinfo->flags, WAIT))
++		return !queue_work(wkq->q, &wkinfo->wk);
++	else
++		return !schedule_work(&wkinfo->wk);
++}
++
++static void do_wkq(struct au_wkinfo *wkinfo)
++{
++	unsigned int idle, n;
++	int i, idle_idx;
++
++	while (1) {
++		if (au_ftest_wkq(wkinfo->flags, WAIT)) {
++			idle_idx = 0;
++			idle = UINT_MAX;
++			for (i = 0; i < aufs_nwkq; i++) {
++				n = atomic_inc_return(&au_wkq[i].busy);
++				if (n == 1 && !enqueue(au_wkq + i, wkinfo))
++					return; /* success */
++
++				if (n < idle) {
++					idle_idx = i;
++					idle = n;
++				}
++				atomic_dec(&au_wkq[i].busy);
++			}
++		} else
++			idle_idx = aufs_nwkq;
++
++		atomic_inc(&au_wkq[idle_idx].busy);
++		if (!enqueue(au_wkq + idle_idx, wkinfo))
++			return; /* success */
++
++		/* impossible? */
++		AuWarn1("failed to queue_work()\n");
++		yield();
++	}
++}
++
++static void wkq_func(struct work_struct *wk)
++{
++	struct au_wkinfo *wkinfo = container_of(wk, struct au_wkinfo, wk);
++
++	wkinfo->func(wkinfo->args);
++	atomic_dec(wkinfo->busyp);
++	if (au_ftest_wkq(wkinfo->flags, WAIT))
++		complete(wkinfo->comp);
++	else {
++		kobject_put(&au_sbi(wkinfo->sb)->si_kobj);
++		module_put(THIS_MODULE);
++		kfree(wkinfo);
++	}
++}
++
++/*
++ * Since struct completion is large, try allocating it dynamically.
++ */
++#if defined(CONFIG_4KSTACKS) || defined(AuTest4KSTACKS)
++#define AuWkqCompDeclare(name)	struct completion *comp = NULL
++
++static int au_wkq_comp_alloc(struct au_wkinfo *wkinfo, struct completion **comp)
++{
++	*comp = kmalloc(sizeof(**comp), GFP_NOFS);
++	if (*comp) {
++		init_completion(*comp);
++		wkinfo->comp = *comp;
++		return 0;
++	}
++	return -ENOMEM;
++}
++
++static void au_wkq_comp_free(struct completion *comp)
++{
++	kfree(comp);
++}
++
++#else
++
++/* no braces */
++#define AuWkqCompDeclare(name) \
++	DECLARE_COMPLETION_ONSTACK(_ ## name); \
++	struct completion *comp = &_ ## name
++
++static int au_wkq_comp_alloc(struct au_wkinfo *wkinfo, struct completion **comp)
++{
++	wkinfo->comp = *comp;
++	return 0;
++}
++
++static void au_wkq_comp_free(struct completion *comp __maybe_unused)
++{
++	/* empty */
++}
++#endif /* 4KSTACKS */
++
++static void au_wkq_run(struct au_wkinfo *wkinfo)
++{
++	au_dbg_verify_kthread();
++	INIT_WORK(&wkinfo->wk, wkq_func);
++	do_wkq(wkinfo);
++}
++
++int au_wkq_wait(au_wkq_func_t func, void *args)
++{
++	int err;
++	AuWkqCompDeclare(comp);
++	struct au_wkinfo wkinfo = {
++		.flags	= AuWkq_WAIT,
++		.func	= func,
++		.args	= args
++	};
++
++	err = au_wkq_comp_alloc(&wkinfo, &comp);
++	if (!err) {
++		au_wkq_run(&wkinfo);
++		/* no timeout, no interrupt */
++		wait_for_completion(wkinfo.comp);
++		au_wkq_comp_free(comp);
++	}
++
++	return err;
++
++}
++
++int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb)
++{
++	int err;
++	struct au_wkinfo *wkinfo;
++
++	atomic_inc(&au_sbi(sb)->si_nowait.nw_len);
++
++	/*
++	 * wkq_func() must free this wkinfo.
++	 * it highly depends upon the implementation of workqueue.
++	 */
++	err = 0;
++	wkinfo = kmalloc(sizeof(*wkinfo), GFP_NOFS);
++	if (wkinfo) {
++		wkinfo->sb = sb;
++		wkinfo->flags = !AuWkq_WAIT;
++		wkinfo->func = func;
++		wkinfo->args = args;
++		wkinfo->comp = NULL;
++		kobject_get(&au_sbi(sb)->si_kobj);
++		__module_get(THIS_MODULE);
++
++		au_wkq_run(wkinfo);
++	} else {
++		err = -ENOMEM;
++		atomic_dec(&au_sbi(sb)->si_nowait.nw_len);
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_nwt_init(struct au_nowait_tasks *nwt)
++{
++	atomic_set(&nwt->nw_len, 0);
++	/* smp_mb();*/ /* atomic_set */
++	init_waitqueue_head(&nwt->nw_wq);
++}
++
++void au_wkq_fin(void)
++{
++	int i;
++
++	for (i = 0; i < aufs_nwkq; i++)
++		if (au_wkq[i].q && !IS_ERR(au_wkq[i].q))
++			destroy_workqueue(au_wkq[i].q);
++	kfree(au_wkq);
++}
++
++int __init au_wkq_init(void)
++{
++	int err, i;
++	struct au_wkq *nowaitq;
++
++	/* '+1' is for accounting of nowait queue */
++	err = -ENOMEM;
++	au_wkq = kcalloc(aufs_nwkq + 1, sizeof(*au_wkq), GFP_NOFS);
++	if (unlikely(!au_wkq))
++		goto out;
++
++	err = 0;
++	for (i = 0; i < aufs_nwkq; i++) {
++		au_wkq[i].q = create_singlethread_workqueue(AUFS_WKQ_NAME);
++		if (au_wkq[i].q && !IS_ERR(au_wkq[i].q)) {
++			atomic_set(&au_wkq[i].busy, 0);
++			continue;
++		}
++
++		err = PTR_ERR(au_wkq[i].q);
++		au_wkq_fin();
++		goto out;
++	}
++
++	/* nowait accounting */
++	nowaitq = au_wkq + aufs_nwkq;
++	atomic_set(&nowaitq->busy, 0);
++	nowaitq->q = NULL;
++	/* smp_mb(); */ /* atomic_set */
++
++ out:
++	return err;
++}
+diff -uNr test/fs/aufs/wkq.h aufs2-standalone/fs/aufs/wkq.h
+--- test/fs/aufs/wkq.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/wkq.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,72 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * workqueue for asynchronous/super-io operations
++ * todo: try new credentials management scheme
++ */
++
++#ifndef __AUFS_WKQ_H__
++#define __AUFS_WKQ_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/sched.h>
++#include <linux/workqueue.h>
++#include <linux/aufs_type.h>
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * in the next operation, wait for the 'nowait' tasks in system-wide workqueue
++ */
++struct au_nowait_tasks {
++	atomic_t		nw_len;
++	wait_queue_head_t	nw_wq;
++};
++
++/* ---------------------------------------------------------------------- */
++
++typedef void (*au_wkq_func_t)(void *args);
++
++/* wkq flags */
++#define AuWkq_WAIT	1
++#define au_ftest_wkq(flags, name)	((flags) & AuWkq_##name)
++#define au_fset_wkq(flags, name)	{ (flags) |= AuWkq_##name; }
++#define au_fclr_wkq(flags, name)	{ (flags) &= ~AuWkq_##name; }
++
++/* wkq.c */
++int au_wkq_wait(au_wkq_func_t func, void *args);
++int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb);
++void au_nwt_init(struct au_nowait_tasks *nwt);
++int __init au_wkq_init(void);
++void au_wkq_fin(void);
++
++/* ---------------------------------------------------------------------- */
++
++static inline int au_test_wkq(struct task_struct *tsk)
++{
++	return !tsk->mm && !strcmp(tsk->comm, AUFS_WKQ_NAME);
++}
++
++static inline void au_nwt_done(struct au_nowait_tasks *nwt)
++{
++	if (!atomic_dec_return(&nwt->nw_len))
++		wake_up_all(&nwt->nw_wq);
++}
++
++static inline int au_nwt_flush(struct au_nowait_tasks *nwt)
++{
++	wait_event(nwt->nw_wq, !atomic_read(&nwt->nw_len));
++	return 0;
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_WKQ_H__ */
+diff -uNr test/fs/aufs/xino.c aufs2-standalone/fs/aufs/xino.c
+--- test/fs/aufs/xino.c	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/fs/aufs/xino.c	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,1180 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++/*
++ * external inode number translation table and bitmap
++ */
++
++#include <linux/seq_file.h>
++#include <linux/uaccess.h>
++#include "aufs.h"
++
++ssize_t xino_fread(au_readf_t func, struct file *file, void *buf, size_t size,
++		   loff_t *pos)
++{
++	ssize_t err;
++	mm_segment_t oldfs;
++
++	oldfs = get_fs();
++	set_fs(KERNEL_DS);
++	do {
++		/* todo: signal_pending? */
++		err = func(file, (char __user *)buf, size, pos);
++	} while (err == -EAGAIN || err == -EINTR);
++	set_fs(oldfs);
++
++#if 0 /* reserved for future use */
++	if (err > 0)
++		fsnotify_access(file->f_dentry);
++#endif
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static ssize_t do_xino_fwrite(au_writef_t func, struct file *file, void *buf,
++			      size_t size, loff_t *pos)
++{
++	ssize_t err;
++	mm_segment_t oldfs;
++
++	oldfs = get_fs();
++	set_fs(KERNEL_DS);
++	lockdep_off();
++	do {
++		/* todo: signal_pending? */
++		err = func(file, (const char __user *)buf, size, pos);
++	} while (err == -EAGAIN || err == -EINTR);
++	lockdep_on();
++	set_fs(oldfs);
++
++#if 0 /* reserved for future use */
++	if (err > 0)
++		fsnotify_modify(file->f_dentry);
++#endif
++
++	return err;
++}
++
++struct do_xino_fwrite_args {
++	ssize_t *errp;
++	au_writef_t func;
++	struct file *file;
++	void *buf;
++	size_t size;
++	loff_t *pos;
++};
++
++static void call_do_xino_fwrite(void *args)
++{
++	struct do_xino_fwrite_args *a = args;
++	*a->errp = do_xino_fwrite(a->func, a->file, a->buf, a->size, a->pos);
++}
++
++ssize_t xino_fwrite(au_writef_t func, struct file *file, void *buf, size_t size,
++		    loff_t *pos)
++{
++	ssize_t err;
++
++	/* todo: signal block and no wkq? */
++	/* todo: new credential scheme */
++	/*
++	 * it breaks RLIMIT_FSIZE and normal user's limit,
++	 * users should care about quota and real 'filesystem full.'
++	 */
++	if (!au_test_wkq(current)) {
++		int wkq_err;
++		struct do_xino_fwrite_args args = {
++			.errp	= &err,
++			.func	= func,
++			.file	= file,
++			.buf	= buf,
++			.size	= size,
++			.pos	= pos
++		};
++
++		wkq_err = au_wkq_wait(call_do_xino_fwrite, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	} else
++		err = do_xino_fwrite(func, file, buf, size, pos);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * create a new xinofile at the same place/path as @base_file.
++ */
++static struct file *au_xino_create2(struct file *base_file,
++				    struct file *copy_src)
++{
++	struct file *file;
++	struct dentry *base, *dentry, *parent;
++	struct inode *dir;
++	struct qstr *name;
++	int err;
++
++	base = base_file->f_dentry;
++	parent = base->d_parent; /* dir inode is locked */
++	dir = parent->d_inode;
++	IMustLock(dir);
++
++	file = ERR_PTR(-EINVAL);
++	name = &base->d_name;
++	dentry = vfsub_lookup_one_len(name->name, parent, name->len);
++	if (IS_ERR(dentry)) {
++		file = (void *)dentry;
++		AuErr("%.*s lookup err %ld\n", AuLNPair(name), PTR_ERR(dentry));
++		goto out;
++	}
++
++	/* no need to mnt_want_write() since we call dentry_open() later */
++	err = vfs_create(dir, dentry, S_IRUGO | S_IWUGO, NULL);
++	if (unlikely(err)) {
++		file = ERR_PTR(err);
++		AuErr("%.*s create err %d\n", AuLNPair(name), err);
++		goto out_dput;
++	}
++
++	file = dentry_open(dget(dentry), mntget(base_file->f_vfsmnt),
++			   O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE);
++	if (IS_ERR(file)) {
++		AuErr("%.*s open err %ld\n", AuLNPair(name), PTR_ERR(file));
++		goto out_dput;
++	}
++
++	err = vfsub_unlink(dir, &file->f_path, /*force*/0);
++	if (unlikely(err)) {
++		AuErr("%.*s unlink err %d\n", AuLNPair(name), err);
++		goto out_fput;
++	}
++
++	if (copy_src) {
++		/* no one can touch copy_src xino */
++		err = au_copy_file(file, copy_src,
++				   i_size_read(copy_src->f_dentry->d_inode));
++		if (unlikely(err)) {
++			AuErr("%.*s copy err %d\n", AuLNPair(name), err);
++			goto out_fput;
++		}
++	}
++	goto out_dput; /* success */
++
++ out_fput:
++	fput(file);
++	file = ERR_PTR(err);
++ out_dput:
++	dput(dentry);
++ out:
++	return file;
++}
++
++struct au_xino_lock_dir {
++	struct au_hinode *hdir;
++	struct dentry *parent;
++	struct mutex *mtx;
++};
++
++static void au_xino_lock_dir(struct super_block *sb, struct file *xino,
++			     struct au_xino_lock_dir *ldir)
++{
++	aufs_bindex_t brid, bindex;
++
++	ldir->hdir = NULL;
++	bindex = -1;
++	brid = au_xino_brid(sb);
++	if (brid >= 0)
++		bindex = au_br_index(sb, brid);
++	if (bindex >= 0) {
++		ldir->hdir = au_hi(sb->s_root->d_inode, bindex);
++		au_hin_imtx_lock_nested(ldir->hdir, AuLsc_I_PARENT);
++	} else {
++		ldir->parent = dget_parent(xino->f_dentry);
++		ldir->mtx = &ldir->parent->d_inode->i_mutex;
++		mutex_lock_nested(ldir->mtx, AuLsc_I_PARENT);
++	}
++}
++
++static void au_xino_unlock_dir(struct au_xino_lock_dir *ldir)
++{
++	if (ldir->hdir)
++		au_hin_imtx_unlock(ldir->hdir);
++	else {
++		mutex_unlock(ldir->mtx);
++		dput(ldir->parent);
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* trucate xino files asynchronously */
++
++int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex)
++{
++	int err;
++	aufs_bindex_t bi, bend;
++	struct au_branch *br;
++	struct file *new_xino, *file;
++	struct super_block *h_sb;
++	struct au_xino_lock_dir ldir;
++
++	err = -EINVAL;
++	bend = au_sbend(sb);
++	if (unlikely(bindex < 0 || bend < bindex))
++		goto out;
++	br = au_sbr(sb, bindex);
++	file = br->br_xino.xi_file;
++	if (!file)
++		goto out;
++
++	au_xino_lock_dir(sb, file, &ldir);
++	/* mnt_want_write() is unnecessary here */
++	new_xino = au_xino_create2(file, file);
++	au_xino_unlock_dir(&ldir);
++	err = PTR_ERR(new_xino);
++	if (IS_ERR(new_xino))
++		goto out;
++	err = 0;
++	fput(file);
++	br->br_xino.xi_file = new_xino;
++
++	h_sb = br->br_mnt->mnt_sb;
++	for (bi = 0; bi <= bend; bi++) {
++		if (unlikely(bi == bindex))
++			continue;
++		br = au_sbr(sb, bi);
++		if (br->br_mnt->mnt_sb != h_sb)
++			continue;
++
++		fput(br->br_xino.xi_file);
++		br->br_xino.xi_file = new_xino;
++		get_file(new_xino);
++	}
++
++ out:
++	return err;
++}
++
++struct xino_do_trunc_args {
++	struct super_block *sb;
++	struct au_branch *br;
++};
++
++static void xino_do_trunc(void *_args)
++{
++	struct xino_do_trunc_args *args = _args;
++	struct super_block *sb;
++	struct au_branch *br;
++	struct inode *dir;
++	int err;
++	aufs_bindex_t bindex;
++
++	err = 0;
++	sb = args->sb;
++	dir = sb->s_root->d_inode;
++	br = args->br;
++
++	si_noflush_write_lock(sb);
++	ii_read_lock_parent(dir);
++	bindex = au_br_index(sb, br->br_id);
++	err = au_xino_trunc(sb, bindex);
++	if (unlikely(err))
++		goto out;
++
++	if (br->br_xino.xi_file->f_dentry->d_inode->i_blocks
++	    >= br->br_xino_upper)
++		br->br_xino_upper += AUFS_XINO_TRUNC_STEP;
++
++ out:
++	ii_read_unlock(dir);
++	if (unlikely(err))
++		AuWarn("err b%d, (%d)\n", bindex, err);
++	atomic_dec(&br->br_xino_running);
++	atomic_dec(&br->br_count);
++	au_nwt_done(&au_sbi(sb)->si_nowait);
++	si_write_unlock(sb);
++	kfree(args);
++}
++
++static void xino_try_trunc(struct super_block *sb, struct au_branch *br)
++{
++	struct xino_do_trunc_args *args;
++	int wkq_err;
++
++	if (br->br_xino.xi_file->f_dentry->d_inode->i_blocks
++	    < br->br_xino_upper)
++		return;
++
++	if (atomic_inc_return(&br->br_xino_running) > 1)
++		goto out;
++
++	/* lock and kfree() will be called in trunc_xino() */
++	args = kmalloc(sizeof(*args), GFP_NOFS);
++	if (unlikely(!args)) {
++		AuErr1("no memory\n");
++		goto out_args;
++	}
++
++	atomic_inc(&br->br_count);
++	args->sb = sb;
++	args->br = br;
++	wkq_err = au_wkq_nowait(xino_do_trunc, args, sb);
++	if (!wkq_err)
++		return; /* success */
++
++	AuErr("wkq %d\n", wkq_err);
++	atomic_dec(&br->br_count);
++
++ out_args:
++	kfree(args);
++ out:
++	atomic_dec(&br->br_xino_running);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static const loff_t au_loff_max = LLONG_MAX;
++
++static int au_xino_do_write(au_writef_t write, struct file *file,
++			    ino_t h_ino, ino_t ino)
++{
++	loff_t pos;
++	ssize_t sz;
++
++	pos = h_ino;
++	if (unlikely(au_loff_max / sizeof(ino) - 1 < pos)) {
++		AuIOErr1("too large hi%lu\n", (unsigned long)h_ino);
++		return -EFBIG;
++	}
++	pos *= sizeof(ino);
++	sz = xino_fwrite(write, file, &ino, sizeof(ino), &pos);
++	if (sz == sizeof(ino))
++		return 0; /* success */
++
++	AuIOErr("write failed (%zd)\n", sz);
++	return -EIO;
++}
++
++/*
++ * write @ino to the xinofile for the specified branch{@sb, @bindex}
++ * at the position of @h_ino.
++ * even if @ino is zero, it is written to the xinofile and means no entry.
++ * if the size of the xino file on a specific filesystem exceeds the watermark,
++ * try truncating it.
++ */
++int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		  ino_t ino)
++{
++	int err;
++	unsigned int mnt_flags;
++	struct au_branch *br;
++
++	BUILD_BUG_ON(sizeof(long long) != sizeof(au_loff_max)
++		     || ((loff_t)-1) > 0);
++
++	mnt_flags = au_mntflags(sb);
++	if (!au_opt_test(mnt_flags, XINO))
++		return 0;
++
++	br = au_sbr(sb, bindex);
++	err = au_xino_do_write(au_sbi(sb)->si_xwrite, br->br_xino.xi_file,
++			       h_ino, ino);
++	if (!err) {
++		if (au_opt_test(mnt_flags, TRUNC_XINO)
++		    && au_test_fs_trunc_xino(br->br_mnt->mnt_sb))
++			xino_try_trunc(sb, br);
++		return 0; /* success */
++	}
++
++	AuIOErr("write failed (%d)\n", err);
++	return -EIO;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* aufs inode number bitmap */
++
++static const int page_bits = (int)PAGE_SIZE * BITS_PER_BYTE;
++static ino_t xib_calc_ino(unsigned long pindex, int bit)
++{
++	ino_t ino;
++
++	AuDebugOn(bit < 0 || page_bits <= bit);
++	ino = AUFS_FIRST_INO + pindex * page_bits + bit;
++	return ino;
++}
++
++static void xib_calc_bit(ino_t ino, unsigned long *pindex, int *bit)
++{
++	AuDebugOn(ino < AUFS_FIRST_INO);
++	ino -= AUFS_FIRST_INO;
++	*pindex = ino / page_bits;
++	*bit = ino % page_bits;
++}
++
++static int xib_pindex(struct super_block *sb, unsigned long pindex)
++{
++	int err;
++	loff_t pos;
++	ssize_t sz;
++	struct au_sbinfo *sbinfo;
++	struct file *xib;
++	unsigned long *p;
++
++	sbinfo = au_sbi(sb);
++	MtxMustLock(&sbinfo->si_xib_mtx);
++	AuDebugOn(pindex > ULONG_MAX / PAGE_SIZE
++		  || !au_opt_test(sbinfo->si_mntflags, XINO));
++
++	if (pindex == sbinfo->si_xib_last_pindex)
++		return 0;
++
++	xib = sbinfo->si_xib;
++	p = sbinfo->si_xib_buf;
++	pos = sbinfo->si_xib_last_pindex;
++	pos *= PAGE_SIZE;
++	sz = xino_fwrite(sbinfo->si_xwrite, xib, p, PAGE_SIZE, &pos);
++	if (unlikely(sz != PAGE_SIZE))
++		goto out;
++
++	pos = pindex;
++	pos *= PAGE_SIZE;
++	if (i_size_read(xib->f_dentry->d_inode) >= pos + PAGE_SIZE)
++		sz = xino_fread(sbinfo->si_xread, xib, p, PAGE_SIZE, &pos);
++	else {
++		memset(p, 0, PAGE_SIZE);
++		sz = xino_fwrite(sbinfo->si_xwrite, xib, p, PAGE_SIZE, &pos);
++	}
++	if (sz == PAGE_SIZE) {
++		sbinfo->si_xib_last_pindex = pindex;
++		return 0; /* success */
++	}
++
++ out:
++	AuIOErr1("write failed (%zd)\n", sz);
++	err = sz;
++	if (sz >= 0)
++		err = -EIO;
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_xino_write0(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		   ino_t ino)
++{
++	int err, bit;
++	unsigned long pindex;
++	struct au_sbinfo *sbinfo;
++
++	if (!au_opt_test(au_mntflags(sb), XINO))
++		return 0;
++
++	err = 0;
++	if (ino) {
++		sbinfo = au_sbi(sb);
++		xib_calc_bit(ino, &pindex, &bit);
++		AuDebugOn(page_bits <= bit);
++		mutex_lock(&sbinfo->si_xib_mtx);
++		err = xib_pindex(sb, pindex);
++		if (!err) {
++			clear_bit(bit, sbinfo->si_xib_buf);
++			sbinfo->si_xib_next_bit = bit;
++		}
++		mutex_unlock(&sbinfo->si_xib_mtx);
++	}
++
++	if (!err)
++		err = au_xino_write(sb, bindex, h_ino, 0);
++	return err;
++}
++
++/* get an unused inode number from bitmap */
++ino_t au_xino_new_ino(struct super_block *sb)
++{
++	ino_t ino;
++	unsigned long *p, pindex, ul, pend;
++	struct au_sbinfo *sbinfo;
++	struct file *file;
++	int free_bit, err;
++
++	if (!au_opt_test(au_mntflags(sb), XINO))
++		return iunique(sb, AUFS_FIRST_INO);
++
++	sbinfo = au_sbi(sb);
++	mutex_lock(&sbinfo->si_xib_mtx);
++	p = sbinfo->si_xib_buf;
++	free_bit = sbinfo->si_xib_next_bit;
++	if (free_bit < page_bits && !test_bit(free_bit, p))
++		goto out; /* success */
++	free_bit = find_first_zero_bit(p, page_bits);
++	if (free_bit < page_bits)
++		goto out; /* success */
++
++	pindex = sbinfo->si_xib_last_pindex;
++	for (ul = pindex - 1; ul < ULONG_MAX; ul--) {
++		err = xib_pindex(sb, ul);
++		if (unlikely(err))
++			goto out_err;
++		free_bit = find_first_zero_bit(p, page_bits);
++		if (free_bit < page_bits)
++			goto out; /* success */
++	}
++
++	file = sbinfo->si_xib;
++	pend = i_size_read(file->f_dentry->d_inode) / PAGE_SIZE;
++	for (ul = pindex + 1; ul <= pend; ul++) {
++		err = xib_pindex(sb, ul);
++		if (unlikely(err))
++			goto out_err;
++		free_bit = find_first_zero_bit(p, page_bits);
++		if (free_bit < page_bits)
++			goto out; /* success */
++	}
++	BUG();
++
++ out:
++	set_bit(free_bit, p);
++	sbinfo->si_xib_next_bit++;
++	pindex = sbinfo->si_xib_last_pindex;
++	mutex_unlock(&sbinfo->si_xib_mtx);
++	ino = xib_calc_ino(pindex, free_bit);
++	AuDbg("i%lu\n", (unsigned long)ino);
++	return ino;
++ out_err:
++	mutex_unlock(&sbinfo->si_xib_mtx);
++	AuDbg("i0\n");
++	return 0;
++}
++
++/*
++ * read @ino from xinofile for the specified branch{@sb, @bindex}
++ * at the position of @h_ino.
++ * if @ino does not exist and @do_new is true, get new one.
++ */
++int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		 ino_t *ino)
++{
++	int err;
++	ssize_t sz;
++	loff_t pos;
++	struct file *file;
++	struct au_sbinfo *sbinfo;
++
++	*ino = 0;
++	if (!au_opt_test(au_mntflags(sb), XINO))
++		return 0; /* no xino */
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	pos = h_ino;
++	if (unlikely(au_loff_max / sizeof(*ino) - 1 < pos)) {
++		AuIOErr1("too large hi%lu\n", (unsigned long)h_ino);
++		return -EFBIG;
++	}
++	pos *= sizeof(*ino);
++
++	file = au_sbr(sb, bindex)->br_xino.xi_file;
++	if (i_size_read(file->f_dentry->d_inode) < pos + sizeof(*ino))
++		return 0; /* no ino */
++
++	sz = xino_fread(sbinfo->si_xread, file, ino, sizeof(*ino), &pos);
++	if (sz == sizeof(*ino))
++		return 0; /* success */
++
++	err = sz;
++	if (unlikely(sz >= 0)) {
++		err = -EIO;
++		AuIOErr("xino read error (%zd)\n", sz);
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* create and set a new xino file */
++
++struct file *au_xino_create(struct super_block *sb, char *fname, int silent)
++{
++	struct file *file;
++	struct dentry *h_parent, *d;
++	struct inode *h_dir;
++	int err;
++
++	/*
++	 * at mount-time, and the xino file is the default path,
++	 * hinotify is disabled so we have no inotify events to ignore.
++	 * when a user specified the xino, we cannot get au_hdir to be ignored.
++	 */
++	file = vfsub_filp_open(fname, O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE,
++			       S_IRUGO | S_IWUGO);
++	if (IS_ERR(file)) {
++		if (!silent)
++			AuErr("open %s(%ld)\n", fname, PTR_ERR(file));
++		return file;
++	}
++
++	/* keep file count */
++	h_parent = dget_parent(file->f_dentry);
++	h_dir = h_parent->d_inode;
++	mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
++	/* mnt_want_write() is unnecessary here */
++	err = vfsub_unlink(h_dir, &file->f_path, /*force*/0);
++	mutex_unlock(&h_dir->i_mutex);
++	dput(h_parent);
++	if (unlikely(err)) {
++		if (!silent)
++			AuErr("unlink %s(%d)\n", fname, err);
++		goto out;
++	}
++
++	err = -EINVAL;
++	d = file->f_dentry;
++	if (unlikely(sb == d->d_sb)) {
++		if (!silent)
++			AuErr("%s must be outside\n", fname);
++		goto out;
++	}
++	if (unlikely(au_test_fs_bad_xino(d->d_sb))) {
++		if (!silent)
++			AuErr("xino doesn't support %s(%s)\n",
++			      fname, au_sbtype(d->d_sb));
++		goto out;
++	}
++	return file; /* success */
++
++ out:
++	fput(file);
++	file = ERR_PTR(err);
++	return file;
++}
++
++/*
++ * find another branch who is on the same filesystem of the specified
++ * branch{@btgt}. search until @bend.
++ */
++static int is_sb_shared(struct super_block *sb, aufs_bindex_t btgt,
++			aufs_bindex_t bend)
++{
++	aufs_bindex_t bindex;
++	struct super_block *tgt_sb = au_sbr_sb(sb, btgt);
++
++	for (bindex = 0; bindex < btgt; bindex++)
++		if (unlikely(tgt_sb == au_sbr_sb(sb, bindex)))
++			return bindex;
++	for (bindex++; bindex <= bend; bindex++)
++		if (unlikely(tgt_sb == au_sbr_sb(sb, bindex)))
++			return bindex;
++	return -1;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * initialize the xinofile for the specified branch @br
++ * at the place/path where @base_file indicates.
++ * test whether another branch is on the same filesystem or not,
++ * if @do_test is true.
++ */
++int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t h_ino,
++	       struct file *base_file, int do_test)
++{
++	int err;
++	ino_t ino;
++	aufs_bindex_t bend, bindex;
++	struct au_branch *shared_br, *b;
++	struct file *file;
++	struct super_block *tgt_sb;
++
++	shared_br = NULL;
++	bend = au_sbend(sb);
++	if (do_test) {
++		tgt_sb = br->br_mnt->mnt_sb;
++		for (bindex = 0; bindex <= bend; bindex++) {
++			b = au_sbr(sb, bindex);
++			if (tgt_sb == b->br_mnt->mnt_sb) {
++				shared_br = b;
++				break;
++			}
++		}
++	}
++
++	if (!shared_br || !shared_br->br_xino.xi_file) {
++		struct au_xino_lock_dir ldir;
++
++		au_xino_lock_dir(sb, base_file, &ldir);
++		/* mnt_want_write() is unnecessary here */
++		file = au_xino_create2(base_file, NULL);
++		au_xino_unlock_dir(&ldir);
++		err = PTR_ERR(file);
++		if (IS_ERR(file))
++			goto out;
++		br->br_xino.xi_file = file;
++	} else {
++		br->br_xino.xi_file = shared_br->br_xino.xi_file;
++		get_file(br->br_xino.xi_file);
++	}
++
++	ino = AUFS_ROOT_INO;
++	err = au_xino_do_write(au_sbi(sb)->si_xwrite, br->br_xino.xi_file,
++			       h_ino, ino);
++	if (!err)
++		return 0; /* success */
++
++
++ out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* trucate a xino bitmap file */
++
++/* todo: slow */
++static int do_xib_restore(struct super_block *sb, struct file *file, void *page)
++{
++	int err, bit;
++	ssize_t sz;
++	unsigned long pindex;
++	loff_t pos, pend;
++	struct au_sbinfo *sbinfo;
++	au_readf_t func;
++	ino_t *ino;
++	unsigned long *p;
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	p = sbinfo->si_xib_buf;
++	func = sbinfo->si_xread;
++	pend = i_size_read(file->f_dentry->d_inode);
++	pos = 0;
++	while (pos < pend) {
++		sz = xino_fread(func, file, page, PAGE_SIZE, &pos);
++		err = sz;
++		if (unlikely(sz <= 0))
++			goto out;
++
++		err = 0;
++		for (ino = page; sz > 0; ino++, sz -= sizeof(ino)) {
++			if (unlikely(*ino < AUFS_FIRST_INO))
++				continue;
++
++			xib_calc_bit(*ino, &pindex, &bit);
++			AuDebugOn(page_bits <= bit);
++			err = xib_pindex(sb, pindex);
++			if (!err)
++				set_bit(bit, p);
++			else
++				goto out;
++		}
++	}
++
++ out:
++	return err;
++}
++
++static int xib_restore(struct super_block *sb)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	void *page;
++
++	err = -ENOMEM;
++	page = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!page))
++		goto out;
++
++	err = 0;
++	bend = au_sbend(sb);
++	for (bindex = 0; !err && bindex <= bend; bindex++)
++		if (!bindex || is_sb_shared(sb, bindex, bindex - 1) < 0)
++			err = do_xib_restore
++				(sb, au_sbr(sb, bindex)->br_xino.xi_file, page);
++		else
++			AuDbg("b%d\n", bindex);
++	free_page((unsigned long)page);
++
++ out:
++	return err;
++}
++
++int au_xib_trunc(struct super_block *sb)
++{
++	int err;
++	ssize_t sz;
++	loff_t pos;
++	struct au_xino_lock_dir ldir;
++	struct au_sbinfo *sbinfo;
++	unsigned long *p;
++	struct file *file;
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	if (!au_opt_test(sbinfo->si_mntflags, XINO))
++		goto out;
++
++	file = sbinfo->si_xib;
++	if (i_size_read(file->f_dentry->d_inode) <= PAGE_SIZE)
++		goto out;
++
++	au_xino_lock_dir(sb, file, &ldir);
++	/* mnt_want_write() is unnecessary here */
++	file = au_xino_create2(sbinfo->si_xib, NULL);
++	au_xino_unlock_dir(&ldir);
++	err = PTR_ERR(file);
++	if (IS_ERR(file))
++		goto out;
++	fput(sbinfo->si_xib);
++	sbinfo->si_xib = file;
++
++	p = sbinfo->si_xib_buf;
++	memset(p, 0, PAGE_SIZE);
++	pos = 0;
++	sz = xino_fwrite(sbinfo->si_xwrite, sbinfo->si_xib, p, PAGE_SIZE, &pos);
++	if (unlikely(sz != PAGE_SIZE)) {
++		err = sz;
++		AuIOErr("err %d\n", err);
++		if (sz >= 0)
++			err = -EIO;
++		goto out;
++	}
++
++	mutex_lock(&sbinfo->si_xib_mtx);
++	/* mnt_want_write() is unnecessary here */
++	err = xib_restore(sb);
++	mutex_unlock(&sbinfo->si_xib_mtx);
++
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * xino mount option handlers
++ */
++static au_readf_t find_readf(struct file *h_file)
++{
++	const struct file_operations *fop = h_file->f_op;
++
++	if (fop) {
++		if (fop->read)
++			return fop->read;
++		if (fop->aio_read)
++			return do_sync_read;
++	}
++	return ERR_PTR(-ENOSYS);
++}
++
++static au_writef_t find_writef(struct file *h_file)
++{
++	const struct file_operations *fop = h_file->f_op;
++
++	if (fop) {
++		if (fop->write)
++			return fop->write;
++		if (fop->aio_write)
++			return do_sync_write;
++	}
++	return ERR_PTR(-ENOSYS);
++}
++
++/* xino bitmap */
++static void xino_clear_xib(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++
++	sbinfo = au_sbi(sb);
++	sbinfo->si_xread = NULL;
++	sbinfo->si_xwrite = NULL;
++	if (sbinfo->si_xib)
++		fput(sbinfo->si_xib);
++	sbinfo->si_xib = NULL;
++	free_page((unsigned long)sbinfo->si_xib_buf);
++	sbinfo->si_xib_buf = NULL;
++}
++
++static int au_xino_set_xib(struct super_block *sb, struct file *base)
++{
++	int err;
++	loff_t pos;
++	struct au_sbinfo *sbinfo;
++	struct file *file;
++
++	sbinfo = au_sbi(sb);
++	file = au_xino_create2(base, sbinfo->si_xib);
++	err = PTR_ERR(file);
++	if (IS_ERR(file))
++		goto out;
++	if (sbinfo->si_xib)
++		fput(sbinfo->si_xib);
++	sbinfo->si_xib = file;
++	sbinfo->si_xread = find_readf(file);
++	sbinfo->si_xwrite = find_writef(file);
++
++	err = -ENOMEM;
++	if (!sbinfo->si_xib_buf)
++		sbinfo->si_xib_buf = (void *)get_zeroed_page(GFP_NOFS);
++	if (unlikely(!sbinfo->si_xib_buf))
++		goto out_unset;
++
++	sbinfo->si_xib_last_pindex = 0;
++	sbinfo->si_xib_next_bit = 0;
++	if (i_size_read(file->f_dentry->d_inode) < PAGE_SIZE) {
++		pos = 0;
++		err = xino_fwrite(sbinfo->si_xwrite, file, sbinfo->si_xib_buf,
++				  PAGE_SIZE, &pos);
++		if (unlikely(err != PAGE_SIZE))
++			goto out_free;
++	}
++	err = 0;
++	goto out; /* success */
++
++ out_free:
++	free_page((unsigned long)sbinfo->si_xib_buf);
++	sbinfo->si_xib_buf = NULL;
++	if (err >= 0)
++		err = -EIO;
++ out_unset:
++	fput(sbinfo->si_xib);
++	sbinfo->si_xib = NULL;
++	sbinfo->si_xread = NULL;
++	sbinfo->si_xwrite = NULL;
++ out:
++	return err;
++}
++
++/* xino for each branch */
++static void xino_clear_br(struct super_block *sb)
++{
++	aufs_bindex_t bindex, bend;
++	struct au_branch *br;
++
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		if (!br || !br->br_xino.xi_file)
++			continue;
++
++		fput(br->br_xino.xi_file);
++		br->br_xino.xi_file = NULL;
++	}
++}
++
++static int au_xino_set_br(struct super_block *sb, struct file *base)
++{
++	int err;
++	ino_t ino;
++	aufs_bindex_t bindex, bend, bshared;
++	struct {
++		struct file *old, *new;
++	} *fpair, *p;
++	struct au_branch *br;
++	struct inode *inode;
++	au_writef_t writef;
++
++	err = -ENOMEM;
++	bend = au_sbend(sb);
++	fpair = kcalloc(bend + 1, sizeof(*fpair), GFP_NOFS);
++	if (unlikely(!fpair))
++		goto out;
++
++	inode = sb->s_root->d_inode;
++	ino = AUFS_ROOT_INO;
++	writef = au_sbi(sb)->si_xwrite;
++	for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++) {
++		br = au_sbr(sb, bindex);
++		bshared = is_sb_shared(sb, bindex, bindex - 1);
++		if (bshared >= 0) {
++			/* shared xino */
++			*p = fpair[bshared];
++			get_file(p->new);
++		}
++
++		if (!p->new) {
++			/* new xino */
++			p->old = br->br_xino.xi_file;
++			p->new = au_xino_create2(base, br->br_xino.xi_file);
++			err = PTR_ERR(p->new);
++			if (IS_ERR(p->new)) {
++				p->new = NULL;
++				goto out_pair;
++			}
++		}
++
++		err = au_xino_do_write(writef, p->new,
++				       au_h_iptr(inode, bindex)->i_ino, ino);
++		if (unlikely(err))
++			goto out_pair;
++	}
++
++	for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++) {
++		br = au_sbr(sb, bindex);
++		if (br->br_xino.xi_file)
++			fput(br->br_xino.xi_file);
++		get_file(p->new);
++		br->br_xino.xi_file = p->new;
++	}
++
++ out_pair:
++	for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++)
++		if (p->new)
++			fput(p->new);
++		else
++			break;
++	kfree(fpair);
++ out:
++	return err;
++}
++
++void au_xino_clr(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++
++	xino_clear_xib(sb);
++	xino_clear_br(sb);
++	sbinfo = au_sbi(sb);
++	/* lvalue, do not call au_mntflags() */
++	au_opt_clr(sbinfo->si_mntflags, XINO);
++}
++
++int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount)
++{
++	int err, skip;
++	struct dentry *parent, *cur_parent;
++	struct qstr *dname, *cur_name;
++	struct file *cur_xino;
++	struct inode *dir;
++	struct au_sbinfo *sbinfo;
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	parent = dget_parent(xino->file->f_dentry);
++	if (remount) {
++		skip = 0;
++		dname = &xino->file->f_dentry->d_name;
++		cur_xino = sbinfo->si_xib;
++		if (cur_xino) {
++			cur_parent = dget_parent(cur_xino->f_dentry);
++			cur_name = &cur_xino->f_dentry->d_name;
++			skip = (cur_parent == parent
++				&& dname->len == cur_name->len
++				&& !memcmp(dname->name, cur_name->name,
++					   dname->len));
++			dput(cur_parent);
++		}
++		if (skip)
++			goto out;
++	}
++
++	au_opt_set(sbinfo->si_mntflags, XINO);
++	dir = parent->d_inode;
++	mutex_lock_nested(&dir->i_mutex, AuLsc_I_PARENT);
++	/* mnt_want_write() is unnecessary here */
++	err = au_xino_set_xib(sb, xino->file);
++	if (!err)
++		err = au_xino_set_br(sb, xino->file);
++	mutex_unlock(&dir->i_mutex);
++	if (!err)
++		goto out; /* success */
++
++	/* reset all */
++	AuIOErr("failed creating xino(%d).\n", err);
++
++ out:
++	dput(parent);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * create a xinofile at the default place/path.
++ */
++struct file *au_xino_def(struct super_block *sb)
++{
++	struct file *file;
++	char *page, *p;
++	struct au_branch *br;
++	struct super_block *h_sb;
++	struct path path;
++	aufs_bindex_t bend, bindex, bwr;
++
++	br = NULL;
++	bend = au_sbend(sb);
++	bwr = -1;
++	for (bindex = 0; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		if (au_br_writable(br->br_perm)
++		    && !au_test_fs_bad_xino(br->br_mnt->mnt_sb)) {
++			bwr = bindex;
++			break;
++		}
++	}
++
++	if (bwr >= 0) {
++		file = ERR_PTR(-ENOMEM);
++		page = __getname();
++		if (unlikely(!page))
++			goto out;
++		path.mnt = br->br_mnt;
++		path.dentry = au_h_dptr(sb->s_root, bwr);
++		p = d_path(&path, page, PATH_MAX - sizeof(AUFS_XINO_FNAME));
++		file = (void *)p;
++		if (!IS_ERR(p)) {
++			strcat(p, "/" AUFS_XINO_FNAME);
++			AuDbg("%s\n", p);
++			file = au_xino_create(sb, p, /*silent*/0);
++			if (!IS_ERR(file))
++				au_xino_brid_set(sb, br->br_id);
++		}
++		__putname(page);
++	} else {
++		file = au_xino_create(sb, AUFS_XINO_DEFPATH, /*silent*/0);
++		if (IS_ERR(file))
++			goto out;
++		h_sb = file->f_dentry->d_sb;
++		if (unlikely(au_test_fs_bad_xino(h_sb))) {
++			AuErr("xino doesn't support %s(%s)\n",
++			      AUFS_XINO_DEFPATH, au_sbtype(h_sb));
++			fput(file);
++			file = ERR_PTR(-EINVAL);
++		}
++		if (!IS_ERR(file))
++			au_xino_brid_set(sb, -1);
++	}
++
++ out:
++	return file;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_xino_path(struct seq_file *seq, struct file *file)
++{
++	int err;
++
++	err = au_seq_path(seq, &file->f_path);
++	if (unlikely(err < 0))
++		goto out;
++
++	err = 0;
++#define Deleted "\\040(deleted)"
++	seq->count -= sizeof(Deleted) - 1;
++	AuDebugOn(memcmp(seq->buf + seq->count, Deleted,
++			 sizeof(Deleted) - 1));
++#undef Deleted
++
++ out:
++	return err;
++}
+diff -uNr test/include/linux/aufs_type.h aufs2-standalone/include/linux/aufs_type.h
+--- test/include/linux/aufs_type.h	1970-01-01 01:00:00.000000000 +0100
++++ aufs2-standalone/include/linux/aufs_type.h	2009-03-25 19:27:54.000000000 +0100
+@@ -0,0 +1,98 @@
++/*
++ * Copyright (C) 2005-2009 Junjiro R. Okajima
++ *
++ * This program, aufs is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License as published by
++ * the Free Software Foundation; either version 2 of the License, or
++ * (at your option) any later version.
++ */
++
++#ifndef __AUFS_TYPE_H__
++#define __AUFS_TYPE_H__
++
++#include <linux/ioctl.h>
++
++#define AUFS_VERSION	"2-standalone.tree-28-20090316"
++
++/* todo? move this to linux-2.6.19/include/magic.h */
++#define AUFS_SUPER_MAGIC	('a' << 24 | 'u' << 16 | 'f' << 8 | 's')
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_BRANCH_MAX_127
++/* some environments treat 'char' as 'unsigned char' by default */
++typedef signed char aufs_bindex_t;
++#define AUFS_BRANCH_MAX 127
++#else
++typedef short aufs_bindex_t;
++#ifdef CONFIG_AUFS_BRANCH_MAX_511
++#define AUFS_BRANCH_MAX 511
++#elif defined(CONFIG_AUFS_BRANCH_MAX_1023)
++#define AUFS_BRANCH_MAX 1023
++#elif defined(CONFIG_AUFS_BRANCH_MAX_32767)
++#define AUFS_BRANCH_MAX 32767
++#endif
++#endif
++
++#ifdef __KERNEL__
++#ifndef AUFS_BRANCH_MAX
++#error unknown CONFIG_AUFS_BRANCH_MAX value
++#endif
++#endif /* __KERNEL__ */
++
++/* ---------------------------------------------------------------------- */
++
++#define AUFS_NAME		"aufs"
++#define AUFS_FSTYPE		AUFS_NAME
++
++#define AUFS_ROOT_INO		2
++#define AUFS_FIRST_INO		11
++
++#define AUFS_WH_PFX		".wh."
++#define AUFS_WH_PFX_LEN		((int)sizeof(AUFS_WH_PFX) - 1)
++#define AUFS_XINO_FNAME		"." AUFS_NAME ".xino"
++#define AUFS_XINO_DEFPATH	"/tmp/" AUFS_XINO_FNAME
++#define AUFS_XINO_TRUNC_INIT	64 /* blocks */
++#define AUFS_XINO_TRUNC_STEP	4  /* blocks */
++#define AUFS_DIRWH_DEF		3
++#define AUFS_RDCACHE_DEF	10 /* seconds */
++#define AUFS_WKQ_NAME		AUFS_NAME "d"
++#define AUFS_NWKQ_DEF		4
++#define AUFS_MFS_SECOND_DEF	30 /* seconds */
++#define AUFS_PLINK_WARN		100 /* number of plinks */
++
++#define AUFS_DIROPQ_NAME	AUFS_WH_PFX ".opq" /* whiteouted doubly */
++#define AUFS_WH_DIROPQ		AUFS_WH_PFX AUFS_DIROPQ_NAME
++
++#define AUFS_BASE_NAME		AUFS_WH_PFX AUFS_NAME
++#define AUFS_PLINKDIR_NAME	AUFS_WH_PFX "plnk"
++#define AUFS_ORPHDIR_NAME	AUFS_WH_PFX "orph"
++
++/* doubly whiteouted */
++#define AUFS_WH_BASE		AUFS_WH_PFX AUFS_BASE_NAME
++#define AUFS_WH_PLINKDIR	AUFS_WH_PFX AUFS_PLINKDIR_NAME
++#define AUFS_WH_ORPHDIR		AUFS_WH_PFX AUFS_ORPHDIR_NAME
++
++/* branch permission */
++#define AUFS_BRPERM_RW		"rw"
++#define AUFS_BRPERM_RO		"ro"
++#define AUFS_BRPERM_RR		"rr"
++#define AUFS_BRPERM_WH		"wh"
++#define AUFS_BRPERM_NLWH	"nolwh"
++#define AUFS_BRPERM_ROWH	AUFS_BRPERM_RO "+" AUFS_BRPERM_WH
++#define AUFS_BRPERM_RRWH	AUFS_BRPERM_RR "+" AUFS_BRPERM_WH
++#define AUFS_BRPERM_RWNLWH	AUFS_BRPERM_RW "+" AUFS_BRPERM_NLWH
++
++/* ---------------------------------------------------------------------- */
++
++/* ioctl */
++enum {
++	AuCtl_PLINK_MAINT,
++	AuCtl_PLINK_CLEAN
++};
++
++#define AuCtlType		'A'
++#define AUFS_CTL_PLINK_MAINT	_IO(AuCtlType, AuCtl_PLINK_MAINT)
++#define AUFS_CTL_PLINK_CLEAN	_IO(AuCtlType, AuCtl_PLINK_CLEAN)
++
++#endif /* __AUFS_TYPE_H__ */