dcache: d_splice_alias should ignore DCACHE_DISCONNECTED (da093a9b) · Commits · 戴 / test

Any IS_ROOT() alias should be safe to use; there's nothing special about DCACHE_DISCONNECTED dentries. Note that this is in fact useful for filesystems such as btrfs which can legimately encounter a directory with a preexisting IS_ROOT alias on a lookup that crosses into a subvolume. (Those aliases are currently marked DCACHE_DISCONNECTED--but not really for any good reason, and we'll change that soon.) Signed-off-by:

J. Bruce Fields <bfields@redhat.com> Signed-off-by:

Al Viro <viro@zeniv.linux.org.uk>

fs/dcache.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -2649,9 +2649,9 @@ static void __d_materialise_dentry(struct dentry dentry, struct dentry anon)
		* @inode: the inode which may have a disconnected dentry
		* @dentry: a negative dentry which we want to point to the inode.
		*
		* If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and
		* DCACHE_DISCONNECTED), then d_move that in place of the given dentry
		* and return it, else simply d_add the inode to the dentry and return NULL.
		* If inode is a directory and has an IS_ROOT alias, then d_move that in
		* place of the given dentry and return it, else simply d_add the inode
		* to the dentry and return NULL.
		*
		* If a non-IS_ROOT directory is found, the filesystem is corrupt, and
		* we should error out: directories can't have multiple aliases.
		@@ -2678,7 +2678,7 @@ struct dentry d_splice_alias(struct inode inode, struct dentry *dentry)
		spin_lock(&inode->i_lock);
		new = __d_find_any_alias(inode);
		if (new) {
		if (!IS_ROOT(new) \|\| !(new->d_flags & DCACHE_DISCONNECTED)) {
		if (!IS_ROOT(new)) {
		spin_unlock(&inode->i_lock);
		dput(new);
		return ERR_PTR(-EIO);

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