[Devel] [PATCH rh7 07/14] dcache: d_splice_alias should ignore DCACHE_DISCONNECTED

[Andrey Ryabinin]

From: "J. Bruce Fields" <bfields at redhat.com>

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 at redhat.com>
Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>
(cherry picked from commit da093a9b76efca0a7a217af538929e1ecb204466)
Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
---
 fs/dcache.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 549178a85e6c..f4b30d5d2a45 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2788,9 +2788,9 @@ 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.
@@ -2817,7 +2817,7 @@ 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);
-- 
2.21.0