Linux-libre 4.5.1-gnupck-4.5.1-gnu

1 files changed, 497 insertions, 0 deletions

diff --git a/fs/aufs/i_op_del.c b/fs/aufs/i_op_del.c
new file mode 100644
index 000000000..68741aadb
--- /dev/null
+++ b/fs/aufs/i_op_del.c
@@ -0,0 +1,497 @@
+/*
+ * Copyright (C) 2005-2016 Junjiro R. Okajima
+ */
+
+/*
+ * 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, d_inode(dentry))) {
+			err = AuWbrCopyup(au_sbi(sb), dentry);
+			*bcpup = err;
+			if (unlikely(err < 0))
+				goto out;
+		}
+	} else
+		AuDebugOn(bstart < *bcpup
+			  || au_test_ro(sb, *bcpup, d_inode(dentry)));
+	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 {
+		struct au_dinfo *dinfo, *tmp;
+
+		need_wh = -ENOMEM;
+		dinfo = au_di(dentry);
+		tmp = au_di_alloc(sb, AuLsc_DI_TMP);
+		if (tmp) {
+			au_di_cp(tmp, dinfo);
+			au_di_swap(tmp, dinfo);
+			/* returns the number of positive dentries */
+			need_wh = au_lkup_dentry(dentry, bstart + 1, /*type*/0);
+			au_di_swap(tmp, dinfo);
+			au_rw_write_unlock(&tmp->di_rwsem);
+			au_di_free(tmp);
+		}
+	}
+	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);
+	if (d_really_is_positive(dentry)) {
+		err = -ENOENT;
+		if (unlikely(d_is_negative(h_dentry)))
+			goto out;
+		h_inode = d_inode(h_dentry);
+		if (unlikely(!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(d_is_positive(h_dentry)))
+			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_opt_test(au_mntflags(dentry->d_sb), DIRPERM1)
+		     && au_test_h_perm(d_inode(h_parent),
+				       MAY_EXEC | MAY_WRITE)))
+		goto out;
+
+	h_latest = au_sio_lkup_one(&dentry->d_name, h_parent);
+	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_unpin;
+
+	/* returns with the parent is locked and wh_dentry is dget-ed */
+	goto out; /* success */
+
+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;
+	struct inode *inode;
+
+	sb = dentry->d_sb;
+	SiMustAnyLock(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 */
+	inode = d_inode(dentry);
+	au_hn_free(au_hi(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 %pd, b%d failed, %d. ignored\n",
+			h_dentry, bindex, err);
+		err = 0;
+	}
+
+out:
+	AuTraceErr(err);
+	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;
+
+	inode = d_inode(dentry);
+	d_drop(dentry);
+	inode->i_ctime = dir->i_ctime;
+
+	au_dir_ts(dir, bindex);
+	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 bindex,
+		     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, bindex)
+	};
+
+	rerr = au_wh_unlink_dentry(au_h_iptr(dir, bindex), &h_path, dentry);
+	if (!rerr) {
+		au_set_dbwh(dentry, bwh);
+		au_dtime_revert(dt);
+		return 0;
+	}
+
+	AuIOErr("%pd reverting whiteout failed(%d, %d)\n", dentry, err, rerr);
+	return -EIO;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int aufs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	int err;
+	aufs_bindex_t bwh, bindex, bstart;
+	struct inode *inode, *h_dir, *delegated;
+	struct dentry *parent, *wh_dentry;
+	/* to reuduce stack size */
+	struct {
+		struct au_dtime dt;
+		struct au_pin pin;
+		struct path h_path;
+	} *a;
+
+	IMustLock(dir);
+
+	err = -ENOMEM;
+	a = kmalloc(sizeof(*a), GFP_NOFS);
+	if (unlikely(!a))
+		goto out;
+
+	err = aufs_read_lock(dentry, AuLock_DW | AuLock_GEN);
+	if (unlikely(err))
+		goto out_free;
+	err = au_d_hashed_positive(dentry);
+	if (unlikely(err))
+		goto out_unlock;
+	inode = d_inode(dentry);
+	IMustLock(inode);
+	err = -EISDIR;
+	if (unlikely(d_is_dir(dentry)))
+		goto out_unlock; /* possible? */
+
+	bstart = au_dbstart(dentry);
+	bwh = au_dbwh(dentry);
+	bindex = -1;
+	parent = dentry->d_parent; /* dir inode is locked */
+	di_write_lock_parent(parent);
+	wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/0, &bindex, &a->dt,
+					&a->pin);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry))
+		goto out_parent;
+
+	a->h_path.mnt = au_sbr_mnt(dentry->d_sb, bstart);
+	a->h_path.dentry = au_h_dptr(dentry, bstart);
+	dget(a->h_path.dentry);
+	if (bindex == bstart) {
+		h_dir = au_pinned_h_dir(&a->pin);
+		delegated = NULL;
+		err = vfsub_unlink(h_dir, &a->h_path, &delegated, /*force*/0);
+		if (unlikely(err == -EWOULDBLOCK)) {
+			pr_warn("cannot retry for NFSv4 delegation"
+				" for an internal unlink\n");
+			iput(delegated);
+		}
+	} else {
+		/* dir inode is locked */
+		h_dir = d_inode(wh_dentry->d_parent);
+		IMustLock(h_dir);
+		err = 0;
+	}
+
+	if (!err) {
+		vfsub_drop_nlink(inode);
+		epilog(dir, dentry, bindex);
+
+		/* update target timestamps */
+		if (bindex == bstart) {
+			vfsub_update_h_iattr(&a->h_path, /*did*/NULL);
+			/*ignore*/
+			inode->i_ctime = d_inode(a->h_path.dentry)->i_ctime;
+		} else
+			/* todo: this timestamp may be reverted later */
+			inode->i_ctime = h_dir->i_ctime;
+		goto out_unpin; /* success */
+	}
+
+	/* revert */
+	if (wh_dentry) {
+		int rerr;
+
+		rerr = do_revert(err, dir, bindex, bwh, wh_dentry, dentry,
+				 &a->dt);
+		if (rerr)
+			err = rerr;
+	}
+
+out_unpin:
+	au_unpin(&a->pin);
+	dput(wh_dentry);
+	dput(a->h_path.dentry);
+out_parent:
+	di_write_unlock(parent);
+out_unlock:
+	aufs_read_unlock(dentry, AuLock_DW);
+out_free:
+	kfree(a);
+out:
+	return err;
+}
+
+int aufs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	int err, rmdir_later;
+	aufs_bindex_t bwh, bindex, bstart;
+	struct inode *inode;
+	struct dentry *parent, *wh_dentry, *h_dentry;
+	struct au_whtmp_rmdir *args;
+	/* to reuduce stack size */
+	struct {
+		struct au_dtime dt;
+		struct au_pin pin;
+	} *a;
+
+	IMustLock(dir);
+
+	err = -ENOMEM;
+	a = kmalloc(sizeof(*a), GFP_NOFS);
+	if (unlikely(!a))
+		goto out;
+
+	err = aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH | AuLock_GEN);
+	if (unlikely(err))
+		goto out_free;
+	err = au_alive_dir(dentry);
+	if (unlikely(err))
+		goto out_unlock;
+	inode = d_inode(dentry);
+	IMustLock(inode);
+	err = -ENOTDIR;
+	if (unlikely(!d_is_dir(dentry)))
+		goto out_unlock; /* possible? */
+
+	err = -ENOMEM;
+	args = au_whtmp_rmdir_alloc(dir->i_sb, GFP_NOFS);
+	if (unlikely(!args))
+		goto out_unlock;
+
+	parent = dentry->d_parent; /* dir inode is locked */
+	di_write_lock_parent(parent);
+	err = au_test_empty(dentry, &args->whlist);
+	if (unlikely(err))
+		goto out_parent;
+
+	bstart = au_dbstart(dentry);
+	bwh = au_dbwh(dentry);
+	bindex = -1;
+	wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/1, &bindex, &a->dt,
+					&a->pin);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry))
+		goto out_parent;
+
+	h_dentry = au_h_dptr(dentry, bstart);
+	dget(h_dentry);
+	rmdir_later = 0;
+	if (bindex == bstart) {
+		err = renwh_and_rmdir(dentry, bstart, &args->whlist, dir);
+		if (err > 0) {
+			rmdir_later = err;
+			err = 0;
+		}
+	} else {
+		/* stop monitoring */
+		au_hn_free(au_hi(inode, bstart));
+
+		/* dir inode is locked */
+		IMustLock(d_inode(wh_dentry->d_parent));
+		err = 0;
+	}
+
+	if (!err) {
+		vfsub_dead_dir(inode);
+		au_set_dbdiropq(dentry, -1);
+		epilog(dir, dentry, bindex);
+
+		if (rmdir_later) {
+			au_whtmp_kick_rmdir(dir, bstart, h_dentry, args);
+			args = NULL;
+		}
+
+		goto out_unpin; /* success */
+	}
+
+	/* revert */
+	AuLabel(revert);
+	if (wh_dentry) {
+		int rerr;
+
+		rerr = do_revert(err, dir, bindex, bwh, wh_dentry, dentry,
+				 &a->dt);
+		if (rerr)
+			err = rerr;
+	}
+
+out_unpin:
+	au_unpin(&a->pin);
+	dput(wh_dentry);
+	dput(h_dentry);
+out_parent:
+	di_write_unlock(parent);
+	if (args)
+		au_whtmp_rmdir_free(args);
+out_unlock:
+	aufs_read_unlock(dentry, AuLock_DW);
+out_free:
+	kfree(a);
+out:
+	AuTraceErr(err);
+	return err;
+}