Initial import

1 files changed, 1319 insertions, 0 deletions

diff --git a/fs/aufs/cpup.c b/fs/aufs/cpup.c
new file mode 100644
index 000000000..3ea177a5d
--- /dev/null
+++ b/fs/aufs/cpup.c
@@ -0,0 +1,1319 @@
+/*
+ * Copyright (C) 2005-2015 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * copy-up functions, see wbr_policy.c for copy-down
+ */
+
+#include <linux/fs_stack.h>
+#include <linux/mm.h>
+#include "aufs.h"
+
+void au_cpup_attr_flags(struct inode *dst, unsigned int iflags)
+{
+	const unsigned int mask = S_DEAD | S_SWAPFILE | S_PRIVATE
+		| S_NOATIME | S_NOCMTIME | S_AUTOMOUNT;
+
+	BUILD_BUG_ON(sizeof(iflags) != sizeof(dst->i_flags));
+
+	dst->i_flags |= iflags & ~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);
+	fsstack_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;
+
+	/*
+	 * 0 can happen in revalidating.
+	 * h_inode->i_mutex may not be held here, but it is harmless since once
+	 * i_nlink reaches 0, it will never become positive except O_TMPFILE
+	 * case.
+	 * todo: O_TMPFILE+linkat(AT_SYMLINK_FOLLOW) bypassing aufs may cause
+	 *	 the incorrect link count.
+	 */
+	set_nlink(inode, 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->i_flags);
+}
+
+void au_cpup_igen(struct inode *inode, struct inode *h_inode)
+{
+	struct au_iinfo *iinfo = au_ii(inode);
+
+	IiMustWriteLock(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 = d_inode(h_path->dentry);
+	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;
+
+	/* no delegation since this is a directory */
+	err = vfsub_notify_change(&dt->dt_h_path, &attr, /*delegated*/NULL);
+	if (unlikely(err))
+		pr_warn("restoring timestamps failed(%d). ignored\n", err);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* internal use only */
+struct au_cpup_reg_attr {
+	int		valid;
+	struct kstat	st;
+	unsigned int	iflags; /* inode->i_flags */
+};
+
+static noinline_for_stack
+int cpup_iattr(struct dentry *dst, aufs_bindex_t bindex, struct dentry *h_src,
+	       struct au_cpup_reg_attr *h_src_attr)
+{
+	int err, sbits, icex;
+	unsigned int mnt_flags;
+	unsigned char verbose;
+	struct iattr ia;
+	struct path h_path;
+	struct inode *h_isrc, *h_idst;
+	struct kstat *h_st;
+	struct au_branch *br;
+
+	h_path.dentry = au_h_dptr(dst, bindex);
+	h_idst = d_inode(h_path.dentry);
+	br = au_sbr(dst->d_sb, bindex);
+	h_path.mnt = au_br_mnt(br);
+	h_isrc = d_inode(h_src);
+	ia.ia_valid = ATTR_FORCE | ATTR_UID | ATTR_GID
+		| ATTR_ATIME | ATTR_MTIME
+		| ATTR_ATIME_SET | ATTR_MTIME_SET;
+	if (h_src_attr && h_src_attr->valid) {
+		h_st = &h_src_attr->st;
+		ia.ia_uid = h_st->uid;
+		ia.ia_gid = h_st->gid;
+		ia.ia_atime = h_st->atime;
+		ia.ia_mtime = h_st->mtime;
+		if (h_idst->i_mode != h_st->mode
+		    && !S_ISLNK(h_idst->i_mode)) {
+			ia.ia_valid |= ATTR_MODE;
+			ia.ia_mode = h_st->mode;
+		}
+		sbits = !!(h_st->mode & (S_ISUID | S_ISGID));
+		au_cpup_attr_flags(h_idst, h_src_attr->iflags);
+	} else {
+		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;
+		if (h_idst->i_mode != h_isrc->i_mode
+		    && !S_ISLNK(h_idst->i_mode)) {
+			ia.ia_valid |= ATTR_MODE;
+			ia.ia_mode = h_isrc->i_mode;
+		}
+		sbits = !!(h_isrc->i_mode & (S_ISUID | S_ISGID));
+		au_cpup_attr_flags(h_idst, h_isrc->i_flags);
+	}
+	/* no delegation since it is just created */
+	err = vfsub_notify_change(&h_path, &ia, /*delegated*/NULL);
+
+	/* 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, /*delegated*/NULL);
+	}
+
+	icex = br->br_perm & AuBrAttr_ICEX;
+	if (!err) {
+		mnt_flags = au_mntflags(dst->d_sb);
+		verbose = !!au_opt_test(mnt_flags, VERBOSE);
+		err = au_cpup_xattr(h_path.dentry, h_src, icex, verbose);
+	}
+
+	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;
+			}
+			if (unlikely(err < 0))
+				break;
+		} 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_path.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 = &file_inode(dst)->i_mutex;
+			mutex_lock_nested(h_mtx, AuLsc_I_CHILD2);
+			/* no delegation since it is just created */
+			err = vfsub_notify_change(&dst->f_path, ia,
+						  /*delegated*/NULL);
+			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_path.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 au_cp_generic *cpg)
+{
+	int err, i;
+	enum { SRC, DST };
+	struct {
+		aufs_bindex_t bindex;
+		unsigned int flags;
+		struct dentry *dentry;
+		int force_wr;
+		struct file *file;
+		void *label;
+	} *f, file[] = {
+		{
+			.bindex = cpg->bsrc,
+			.flags = O_RDONLY | O_NOATIME | O_LARGEFILE,
+			.label = &&out
+		},
+		{
+			.bindex = cpg->bdst,
+			.flags = O_WRONLY | O_NOATIME | O_LARGEFILE,
+			.force_wr = !!au_ftest_cpup(cpg->flags, RWDST),
+			.label = &&out_src
+		}
+	};
+	struct super_block *sb;
+
+	/* bsrc branch can be ro/rw. */
+	sb = cpg->dentry->d_sb;
+	f = file;
+	for (i = 0; i < 2; i++, f++) {
+		f->dentry = au_h_dptr(cpg->dentry, f->bindex);
+		f->file = au_h_open(cpg->dentry, f->bindex, f->flags,
+				    /*file*/NULL, f->force_wr);
+		err = PTR_ERR(f->file);
+		if (IS_ERR(f->file))
+			goto *f->label;
+	}
+
+	/* try stopping to update while we copyup */
+	IMustLock(d_inode(file[SRC].dentry));
+	err = au_copy_file(file[DST].file, file[SRC].file, cpg->len);
+
+	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 au_cp_generic *cpg,
+			      struct au_cpup_reg_attr *h_src_attr)
+{
+	int err, rerr;
+	loff_t l;
+	struct path h_path;
+	struct inode *h_src_inode, *h_dst_inode;
+
+	err = 0;
+	h_src_inode = au_h_iptr(d_inode(cpg->dentry), cpg->bsrc);
+	l = i_size_read(h_src_inode);
+	if (cpg->len == -1 || l < cpg->len)
+		cpg->len = l;
+	if (cpg->len) {
+		/* try stopping to update while we are referencing */
+		mutex_lock_nested(&h_src_inode->i_mutex, AuLsc_I_CHILD);
+		au_pin_hdir_unlock(cpg->pin);
+
+		h_path.dentry = au_h_dptr(cpg->dentry, cpg->bsrc);
+		h_path.mnt = au_sbr_mnt(cpg->dentry->d_sb, cpg->bsrc);
+		h_src_attr->iflags = h_src_inode->i_flags;
+		if (!au_test_nfs(h_src_inode->i_sb))
+			err = vfs_getattr(&h_path, &h_src_attr->st);
+		else {
+			mutex_unlock(&h_src_inode->i_mutex);
+			err = vfs_getattr(&h_path, &h_src_attr->st);
+			mutex_lock_nested(&h_src_inode->i_mutex, AuLsc_I_CHILD);
+		}
+		if (unlikely(err)) {
+			mutex_unlock(&h_src_inode->i_mutex);
+			goto out;
+		}
+		h_src_attr->valid = 1;
+		err = au_cp_regular(cpg);
+		mutex_unlock(&h_src_inode->i_mutex);
+		rerr = au_pin_hdir_relock(cpg->pin);
+		if (!err && rerr)
+			err = rerr;
+	}
+	if (!err && (h_src_inode->i_state & I_LINKABLE)) {
+		h_path.dentry = au_h_dptr(cpg->dentry, cpg->bdst);
+		h_dst_inode = d_inode(h_path.dentry);
+		spin_lock(&h_dst_inode->i_lock);
+		h_dst_inode->i_state |= I_LINKABLE;
+		spin_unlock(&h_dst_inode->i_lock);
+	}
+
+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;
+	union {
+		char *k;
+		char __user *u;
+	} sym;
+	struct inode *h_inode = d_inode(h_src);
+	const struct inode_operations *h_iop = h_inode->i_op;
+
+	err = -ENOSYS;
+	if (unlikely(!h_iop->readlink))
+		goto out;
+
+	err = -ENOMEM;
+	sym.k = (void *)__get_free_page(GFP_NOFS);
+	if (unlikely(!sym.k))
+		goto out;
+
+	/* unnecessary to support mmap_sem since symlink is not mmap-able */
+	old_fs = get_fs();
+	set_fs(KERNEL_DS);
+	symlen = h_iop->readlink(h_src, sym.u, PATH_MAX);
+	err = symlen;
+	set_fs(old_fs);
+
+	if (symlen > 0) {
+		sym.k[symlen] = 0;
+		err = vfsub_symlink(h_dir, h_path, sym.k);
+	}
+	free_page((unsigned long)sym.k);
+
+out:
+	return err;
+}
+
+static noinline_for_stack
+int cpup_entry(struct au_cp_generic *cpg, struct dentry *dst_parent,
+	       struct au_cpup_reg_attr *h_src_attr)
+{
+	int err;
+	umode_t mode;
+	unsigned int mnt_flags;
+	unsigned char isdir, isreg, force;
+	const unsigned char do_dt = !!au_ftest_cpup(cpg->flags, DTIME);
+	struct au_dtime dt;
+	struct path h_path;
+	struct dentry *h_src, *h_dst, *h_parent;
+	struct inode *h_inode, *h_dir, *dir, *inode;
+	struct super_block *sb;
+
+	/* bsrc branch can be ro/rw. */
+	h_src = au_h_dptr(cpg->dentry, cpg->bsrc);
+	h_inode = d_inode(h_src);
+	AuDebugOn(h_inode != au_h_iptr(d_inode(cpg->dentry), cpg->bsrc));
+
+	/* try stopping to be referenced while we are creating */
+	h_dst = au_h_dptr(cpg->dentry, cpg->bdst);
+	if (au_ftest_cpup(cpg->flags, RENAME))
+		AuDebugOn(strncmp(h_dst->d_name.name, AUFS_WH_PFX,
+				  AUFS_WH_PFX_LEN));
+	h_parent = h_dst->d_parent; /* dir inode is locked */
+	h_dir = d_inode(h_parent);
+	IMustLock(h_dir);
+	AuDebugOn(h_parent != h_dst->d_parent);
+
+	sb = cpg->dentry->d_sb;
+	h_path.mnt = au_sbr_mnt(sb, cpg->bdst);
+	if (do_dt) {
+		h_path.dentry = h_parent;
+		au_dtime_store(&dt, dst_parent, &h_path);
+	}
+	h_path.dentry = h_dst;
+
+	isreg = 0;
+	isdir = 0;
+	mode = h_inode->i_mode;
+	switch (mode & S_IFMT) {
+	case S_IFREG:
+		isreg = 1;
+		err = vfsub_create(h_dir, &h_path, mode | S_IWUSR,
+				   /*want_excl*/true);
+		if (!err)
+			err = au_do_cpup_regular(cpg, h_src_attr);
+		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
+			 */
+			dir = d_inode(dst_parent);
+			if (au_ibstart(dir) == cpg->bdst)
+				au_cpup_attr_nlink(dir, /*force*/1);
+			inode = d_inode(cpg->dentry);
+			au_cpup_attr_nlink(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
+		|| (h_inode->i_state & I_LINKABLE))
+	    /* todo: unnecessary? */
+	    /* && d_inode(cpg->dentry)->i_nlink == 1 */
+	    && cpg->bdst < cpg->bsrc
+	    && !au_ftest_cpup(cpg->flags, KEEPLINO))
+		au_xino_write(sb, cpg->bsrc, h_inode->i_ino, /*ino*/0);
+		/* ignore this error */
+
+	if (!err) {
+		force = 0;
+		if (isreg) {
+			force = !!cpg->len;
+			if (cpg->len == -1)
+				force = !!i_size_read(h_inode);
+		}
+		au_fhsm_wrote(sb, cpg->bdst, force);
+	}
+
+	if (do_dt)
+		au_dtime_revert(&dt);
+	return err;
+}
+
+static int au_do_ren_after_cpup(struct au_cp_generic *cpg, struct path *h_path)
+{
+	int err;
+	struct dentry *dentry, *h_dentry, *h_parent, *parent;
+	struct inode *h_dir;
+	aufs_bindex_t bdst;
+
+	dentry = cpg->dentry;
+	bdst = cpg->bdst;
+	h_dentry = au_h_dptr(dentry, bdst);
+	if (!au_ftest_cpup(cpg->flags, OVERWRITE)) {
+		dget(h_dentry);
+		au_set_h_dptr(dentry, bdst, NULL);
+		err = au_lkup_neg(dentry, bdst, /*wh*/0);
+		if (!err)
+			h_path->dentry = dget(au_h_dptr(dentry, bdst));
+		au_set_h_dptr(dentry, bdst, h_dentry);
+	} else {
+		err = 0;
+		parent = dget_parent(dentry);
+		h_parent = au_h_dptr(parent, bdst);
+		dput(parent);
+		h_path->dentry = vfsub_lkup_one(&dentry->d_name, h_parent);
+		if (IS_ERR(h_path->dentry))
+			err = PTR_ERR(h_path->dentry);
+	}
+	if (unlikely(err))
+		goto out;
+
+	h_parent = h_dentry->d_parent; /* dir inode is locked */
+	h_dir = d_inode(h_parent);
+	IMustLock(h_dir);
+	AuDbg("%pd %pd\n", h_dentry, h_path->dentry);
+	/* no delegation since it is just created */
+	err = vfsub_rename(h_dir, h_dentry, h_dir, h_path, /*delegated*/NULL);
+	dput(h_path->dentry);
+
+out:
+	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.
+ * basic->bsrc can be larger than basic->bdst.
+ */
+static int au_cpup_single(struct au_cp_generic *cpg, struct dentry *dst_parent)
+{
+	int err, rerr;
+	aufs_bindex_t old_ibstart;
+	unsigned char isdir, plink;
+	struct dentry *h_src, *h_dst, *h_parent;
+	struct inode *dst_inode, *h_dir, *inode, *delegated, *src_inode;
+	struct super_block *sb;
+	struct au_branch *br;
+	/* to reuduce stack size */
+	struct {
+		struct au_dtime dt;
+		struct path h_path;
+		struct au_cpup_reg_attr h_src_attr;
+	} *a;
+
+	err = -ENOMEM;
+	a = kmalloc(sizeof(*a), GFP_NOFS);
+	if (unlikely(!a))
+		goto out;
+	a->h_src_attr.valid = 0;
+
+	sb = cpg->dentry->d_sb;
+	br = au_sbr(sb, cpg->bdst);
+	a->h_path.mnt = au_br_mnt(br);
+	h_dst = au_h_dptr(cpg->dentry, cpg->bdst);
+	h_parent = h_dst->d_parent; /* dir inode is locked */
+	h_dir = d_inode(h_parent);
+	IMustLock(h_dir);
+
+	h_src = au_h_dptr(cpg->dentry, cpg->bsrc);
+	inode = d_inode(cpg->dentry);
+
+	if (!dst_parent)
+		dst_parent = dget_parent(cpg->dentry);
+	else
+		dget(dst_parent);
+
+	plink = !!au_opt_test(au_mntflags(sb), PLINK);
+	dst_inode = au_h_iptr(inode, cpg->bdst);
+	if (dst_inode) {
+		if (unlikely(!plink)) {
+			err = -EIO;
+			AuIOErr("hi%lu(i%lu) exists on b%d "
+				"but plink is disabled\n",
+				dst_inode->i_ino, inode->i_ino, cpg->bdst);
+			goto out_parent;
+		}
+
+		if (dst_inode->i_nlink) {
+			const int do_dt = au_ftest_cpup(cpg->flags, DTIME);
+
+			h_src = au_plink_lkup(inode, cpg->bdst);
+			err = PTR_ERR(h_src);
+			if (IS_ERR(h_src))
+				goto out_parent;
+			if (unlikely(d_is_negative(h_src))) {
+				err = -EIO;
+				AuIOErr("i%lu exists on a upper branch "
+					"but not pseudo-linked\n",
+					inode->i_ino);
+				dput(h_src);
+				goto out_parent;
+			}
+
+			if (do_dt) {
+				a->h_path.dentry = h_parent;
+				au_dtime_store(&a->dt, dst_parent, &a->h_path);
+			}
+
+			a->h_path.dentry = h_dst;
+			delegated = NULL;
+			err = vfsub_link(h_src, h_dir, &a->h_path, &delegated);
+			if (!err && au_ftest_cpup(cpg->flags, RENAME))
+				err = au_do_ren_after_cpup(cpg, &a->h_path);
+			if (do_dt)
+				au_dtime_revert(&a->dt);
+			if (unlikely(err == -EWOULDBLOCK)) {
+				pr_warn("cannot retry for NFSv4 delegation"
+					" for an internal link\n");
+				iput(delegated);
+			}
+			dput(h_src);
+			goto out_parent;
+		} else
+			/* todo: cpup_wh_file? */
+			/* udba work */
+			au_update_ibrange(inode, /*do_put_zero*/1);
+	}
+
+	isdir = S_ISDIR(inode->i_mode);
+	old_ibstart = au_ibstart(inode);
+	err = cpup_entry(cpg, dst_parent, &a->h_src_attr);
+	if (unlikely(err))
+		goto out_rev;
+	dst_inode = d_inode(h_dst);
+	mutex_lock_nested(&dst_inode->i_mutex, AuLsc_I_CHILD2);
+	/* todo: necessary? */
+	/* au_pin_hdir_unlock(cpg->pin); */
+
+	err = cpup_iattr(cpg->dentry, cpg->bdst, h_src, &a->h_src_attr);
+	if (unlikely(err)) {
+		/* todo: necessary? */
+		/* au_pin_hdir_relock(cpg->pin); */ /* ignore an error */
+		mutex_unlock(&dst_inode->i_mutex);
+		goto out_rev;
+	}
+
+	if (cpg->bdst < old_ibstart) {
+		if (S_ISREG(inode->i_mode)) {
+			err = au_dy_iaop(inode, cpg->bdst, dst_inode);
+			if (unlikely(err)) {
+				/* ignore an error */
+				/* au_pin_hdir_relock(cpg->pin); */
+				mutex_unlock(&dst_inode->i_mutex);
+				goto out_rev;
+			}
+		}
+		au_set_ibstart(inode, cpg->bdst);
+	} else
+		au_set_ibend(inode, cpg->bdst);
+	au_set_h_iptr(inode, cpg->bdst, au_igrab(dst_inode),
+		      au_hi_flags(inode, isdir));
+
+	/* todo: necessary? */
+	/* err = au_pin_hdir_relock(cpg->pin); */
+	mutex_unlock(&dst_inode->i_mutex);
+	if (unlikely(err))
+		goto out_rev;
+
+	src_inode = d_inode(h_src);
+	if (!isdir
+	    && (src_inode->i_nlink > 1
+		|| src_inode->i_state & I_LINKABLE)
+	    && plink)
+		au_plink_append(inode, cpg->bdst, h_dst);
+
+	if (au_ftest_cpup(cpg->flags, RENAME)) {
+		a->h_path.dentry = h_dst;
+		err = au_do_ren_after_cpup(cpg, &a->h_path);
+	}
+	if (!err)
+		goto out_parent; /* success */
+
+	/* revert */
+out_rev:
+	a->h_path.dentry = h_parent;
+	au_dtime_store(&a->dt, dst_parent, &a->h_path);
+	a->h_path.dentry = h_dst;
+	rerr = 0;
+	if (d_is_positive(h_dst)) {
+		if (!isdir) {
+			/* no delegation since it is just created */
+			rerr = vfsub_unlink(h_dir, &a->h_path,
+					    /*delegated*/NULL, /*force*/0);
+		} else
+			rerr = vfsub_rmdir(h_dir, &a->h_path);
+	}
+	au_dtime_revert(&a->dt);
+	if (rerr) {
+		AuIOErr("failed removing broken entry(%d, %d)\n", err, rerr);
+		err = -EIO;
+	}
+out_parent:
+	dput(dst_parent);
+	kfree(a);
+out:
+	return err;
+}
+
+#if 0 /* reserved */
+struct au_cpup_single_args {
+	int *errp;
+	struct au_cp_generic *cpg;
+	struct dentry *dst_parent;
+};
+
+static void au_call_cpup_single(void *args)
+{
+	struct au_cpup_single_args *a = args;
+
+	au_pin_hdir_acquire_nest(a->cpg->pin);
+	*a->errp = au_cpup_single(a->cpg, a->dst_parent);
+	au_pin_hdir_release(a->cpg->pin);
+}
+#endif
+
+/*
+ * prevent SIGXFSZ in copy-up.
+ * testing CAP_MKNOD is for generic fs,
+ * but CAP_FSETID is for xfs only, currently.
+ */
+static int au_cpup_sio_test(struct au_pin *pin, umode_t mode)
+{
+	int do_sio;
+	struct super_block *sb;
+	struct inode *h_dir;
+
+	do_sio = 0;
+	sb = au_pinned_parent(pin)->d_sb;
+	if (!au_wkq_test()
+	    && (!au_sbi(sb)->si_plink_maint_pid
+		|| au_plink_maint(sb, AuLock_NOPLM))) {
+		switch (mode & S_IFMT) {
+		case S_IFREG:
+			/* no condition about RLIMIT_FSIZE and the file size */
+			do_sio = 1;
+			break;
+		case S_IFCHR:
+		case S_IFBLK:
+			do_sio = !capable(CAP_MKNOD);
+			break;
+		}
+		if (!do_sio)
+			do_sio = ((mode & (S_ISUID | S_ISGID))
+				  && !capable(CAP_FSETID));
+		/* this workaround may be removed in the future */
+		if (!do_sio) {
+			h_dir = au_pinned_h_dir(pin);
+			do_sio = h_dir->i_mode & S_ISVTX;
+		}
+	}
+
+	return do_sio;
+}
+
+#if 0 /* reserved */
+int au_sio_cpup_single(struct au_cp_generic *cpg, struct dentry *dst_parent)
+{
+	int err, wkq_err;
+	struct dentry *h_dentry;
+
+	h_dentry = au_h_dptr(cpg->dentry, cpg->bsrc);
+	if (!au_cpup_sio_test(pin, d_inode(h_dentry)->i_mode))
+		err = au_cpup_single(cpg, dst_parent);
+	else {
+		struct au_cpup_single_args args = {
+			.errp		= &err,
+			.cpg		= cpg,
+			.dst_parent	= dst_parent
+		};
+		wkq_err = au_wkq_wait(au_call_cpup_single, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	return err;
+}
+#endif
+
+/*
+ * copyup the @dentry from the first active lower branch to @bdst,
+ * using au_cpup_single().
+ */
+static int au_cpup_simple(struct au_cp_generic *cpg)
+{
+	int err;
+	unsigned int flags_orig;
+	struct dentry *dentry;
+
+	AuDebugOn(cpg->bsrc < 0);
+
+	dentry = cpg->dentry;
+	DiMustWriteLock(dentry);
+
+	err = au_lkup_neg(dentry, cpg->bdst, /*wh*/1);
+	if (!err) {
+		flags_orig = cpg->flags;
+		au_fset_cpup(cpg->flags, RENAME);
+		err = au_cpup_single(cpg, NULL);
+		cpg->flags = flags_orig;
+		if (!err)
+			return 0; /* success */
+
+		/* revert */
+		au_set_h_dptr(dentry, cpg->bdst, NULL);
+		au_set_dbstart(dentry, cpg->bsrc);
+	}
+
+	return err;
+}
+
+struct au_cpup_simple_args {
+	int *errp;
+	struct au_cp_generic *cpg;
+};
+
+static void au_call_cpup_simple(void *args)
+{
+	struct au_cpup_simple_args *a = args;
+
+	au_pin_hdir_acquire_nest(a->cpg->pin);
+	*a->errp = au_cpup_simple(a->cpg);
+	au_pin_hdir_release(a->cpg->pin);
+}
+
+static int au_do_sio_cpup_simple(struct au_cp_generic *cpg)
+{
+	int err, wkq_err;
+	struct dentry *dentry, *parent;
+	struct file *h_file;
+	struct inode *h_dir;
+
+	dentry = cpg->dentry;
+	h_file = NULL;
+	if (au_ftest_cpup(cpg->flags, HOPEN)) {
+		AuDebugOn(cpg->bsrc < 0);
+		h_file = au_h_open_pre(dentry, cpg->bsrc, /*force_wr*/0);
+		err = PTR_ERR(h_file);
+		if (IS_ERR(h_file))
+			goto out;
+	}
+
+	parent = dget_parent(dentry);
+	h_dir = au_h_iptr(d_inode(parent), cpg->bdst);
+	if (!au_test_h_perm_sio(h_dir, MAY_EXEC | MAY_WRITE)
+	    && !au_cpup_sio_test(cpg->pin, d_inode(dentry)->i_mode))
+		err = au_cpup_simple(cpg);
+	else {
+		struct au_cpup_simple_args args = {
+			.errp		= &err,
+			.cpg		= cpg
+		};
+		wkq_err = au_wkq_wait(au_call_cpup_simple, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	dput(parent);
+	if (h_file)
+		au_h_open_post(dentry, cpg->bsrc, h_file);
+
+out:
+	return err;
+}
+
+int au_sio_cpup_simple(struct au_cp_generic *cpg)
+{
+	aufs_bindex_t bsrc, bend;
+	struct dentry *dentry, *h_dentry;
+
+	if (cpg->bsrc < 0) {
+		dentry = cpg->dentry;
+		bend = au_dbend(dentry);
+		for (bsrc = cpg->bdst + 1; bsrc <= bend; bsrc++) {
+			h_dentry = au_h_dptr(dentry, bsrc);
+			if (h_dentry) {
+				AuDebugOn(d_is_negative(h_dentry));
+				break;
+			}
+		}
+		AuDebugOn(bsrc > bend);
+		cpg->bsrc = bsrc;
+	}
+	AuDebugOn(cpg->bsrc <= cpg->bdst);
+	return au_do_sio_cpup_simple(cpg);
+}
+
+int au_sio_cpdown_simple(struct au_cp_generic *cpg)
+{
+	AuDebugOn(cpg->bdst <= cpg->bsrc);
+	return au_do_sio_cpup_simple(cpg);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * copyup the deleted file for writing.
+ */
+static int au_do_cpup_wh(struct au_cp_generic *cpg, struct dentry *wh_dentry,
+			 struct file *file)
+{
+	int err;
+	unsigned int flags_orig;
+	aufs_bindex_t bsrc_orig;
+	struct dentry *h_d_dst, *h_d_start;
+	struct au_dinfo *dinfo;
+	struct au_hdentry *hdp;
+
+	dinfo = au_di(cpg->dentry);
+	AuRwMustWriteLock(&dinfo->di_rwsem);
+
+	bsrc_orig = cpg->bsrc;
+	cpg->bsrc = dinfo->di_bstart;
+	hdp = dinfo->di_hdentry;
+	h_d_dst = hdp[0 + cpg->bdst].hd_dentry;
+	dinfo->di_bstart = cpg->bdst;
+	hdp[0 + cpg->bdst].hd_dentry = wh_dentry;
+	h_d_start = NULL;
+	if (file) {
+		h_d_start = hdp[0 + cpg->bsrc].hd_dentry;
+		hdp[0 + cpg->bsrc].hd_dentry = au_hf_top(file)->f_path.dentry;
+	}
+	flags_orig = cpg->flags;
+	cpg->flags = !AuCpup_DTIME;
+	err = au_cpup_single(cpg, /*h_parent*/NULL);
+	cpg->flags = flags_orig;
+	if (file) {
+		if (!err)
+			err = au_reopen_nondir(file);
+		hdp[0 + cpg->bsrc].hd_dentry = h_d_start;
+	}
+	hdp[0 + cpg->bdst].hd_dentry = h_d_dst;
+	dinfo->di_bstart = cpg->bsrc;
+	cpg->bsrc = bsrc_orig;
+
+	return err;
+}
+
+static int au_cpup_wh(struct au_cp_generic *cpg, struct file *file)
+{
+	int err;
+	aufs_bindex_t bdst;
+	struct au_dtime dt;
+	struct dentry *dentry, *parent, *h_parent, *wh_dentry;
+	struct au_branch *br;
+	struct path h_path;
+
+	dentry = cpg->dentry;
+	bdst = cpg->bdst;
+	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 = au_br_mnt(br);
+	au_dtime_store(&dt, parent, &h_path);
+	err = au_do_cpup_wh(cpg, wh_dentry, file);
+	if (unlikely(err))
+		goto out_wh;
+
+	dget(wh_dentry);
+	h_path.dentry = wh_dentry;
+	if (!d_is_dir(wh_dentry)) {
+		/* no delegation since it is just created */
+		err = vfsub_unlink(d_inode(h_parent), &h_path,
+				   /*delegated*/NULL, /*force*/0);
+	} else
+		err = vfsub_rmdir(d_inode(h_parent), &h_path);
+	if (unlikely(err)) {
+		AuIOErr("failed remove copied-up tmp file %pd(%d)\n",
+			wh_dentry, err);
+		err = -EIO;
+	}
+	au_dtime_revert(&dt);
+	au_set_hi_wh(d_inode(dentry), bdst, wh_dentry);
+
+out_wh:
+	dput(wh_dentry);
+out:
+	dput(parent);
+	return err;
+}
+
+struct au_cpup_wh_args {
+	int *errp;
+	struct au_cp_generic *cpg;
+	struct file *file;
+};
+
+static void au_call_cpup_wh(void *args)
+{
+	struct au_cpup_wh_args *a = args;
+
+	au_pin_hdir_acquire_nest(a->cpg->pin);
+	*a->errp = au_cpup_wh(a->cpg, a->file);
+	au_pin_hdir_release(a->cpg->pin);
+}
+
+int au_sio_cpup_wh(struct au_cp_generic *cpg, struct file *file)
+{
+	int err, wkq_err;
+	aufs_bindex_t bdst;
+	struct dentry *dentry, *parent, *h_orph, *h_parent;
+	struct inode *dir, *h_dir, *h_tmpdir;
+	struct au_wbr *wbr;
+	struct au_pin wh_pin, *pin_orig;
+
+	dentry = cpg->dentry;
+	bdst = cpg->bdst;
+	parent = dget_parent(dentry);
+	dir = d_inode(parent);
+	h_orph = NULL;
+	h_parent = NULL;
+	h_dir = au_igrab(au_h_iptr(dir, bdst));
+	h_tmpdir = h_dir;
+	pin_orig = NULL;
+	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, dget(h_orph));
+		h_tmpdir = d_inode(h_orph);
+		au_set_h_iptr(dir, bdst, au_igrab(h_tmpdir), /*flags*/0);
+
+		mutex_lock_nested(&h_tmpdir->i_mutex, AuLsc_I_PARENT3);
+		/* todo: au_h_open_pre()? */
+
+		pin_orig = cpg->pin;
+		au_pin_init(&wh_pin, dentry, bdst, AuLsc_DI_PARENT,
+			    AuLsc_I_PARENT3, cpg->pin->udba, AuPin_DI_LOCKED);
+		cpg->pin = &wh_pin;
+	}
+
+	if (!au_test_h_perm_sio(h_tmpdir, MAY_EXEC | MAY_WRITE)
+	    && !au_cpup_sio_test(cpg->pin, d_inode(dentry)->i_mode))
+		err = au_cpup_wh(cpg, file);
+	else {
+		struct au_cpup_wh_args args = {
+			.errp	= &err,
+			.cpg	= cpg,
+			.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);
+		/* todo: au_h_open_post()? */
+		au_set_h_iptr(dir, bdst, au_igrab(h_dir), /*flags*/0);
+		au_set_h_dptr(parent, bdst, h_parent);
+		AuDebugOn(!pin_orig);
+		cpg->pin = pin_orig;
+	}
+	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 au_pin *pin,
+			 struct dentry *h_parent, void *arg),
+	       void *arg)
+{
+	int err;
+	struct au_pin pin;
+	struct dentry *d, *parent, *h_parent, *real_parent, *h_dentry;
+
+	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 */
+		h_dentry = au_h_dptr(d, bdst);
+		if (!h_dentry || d_is_negative(h_dentry)) {
+			if (h_dentry)
+				au_update_dbstart(d);
+
+			au_pin_set_dentry(&pin, d);
+			err = au_do_pin(&pin);
+			if (!err) {
+				err = cp(d, bdst, &pin, 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 au_pin *pin,
+		       struct dentry *h_parent __maybe_unused,
+		       void *arg __maybe_unused)
+{
+	struct au_cp_generic cpg = {
+		.dentry	= dentry,
+		.bdst	= bdst,
+		.bsrc	= -1,
+		.len	= 0,
+		.pin	= pin,
+		.flags	= AuCpup_DTIME
+	};
+	return au_sio_cpup_simple(&cpg);
+}
+
+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 = d_inode(parent);
+	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;
+}