[PATCH 3.12 118/142] CIFS: Fix directory rename error

[Jiri Slaby]

From: Pavel Shilovsky <pshilovsky@xxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

Commit a07d322059db66b84c9eb4f98959df468e88b34b upstream.

CIFS servers process nlink counts differently for files and directories.
In cifs_rename() if we the request fails on the existing target, we
try to remove it through cifs_unlink() but this is not what we want
to do for directories. As the result the following sequence of commands

mkdir {1,2}; mv -T 1 2; rmdir {1,2}; mkdir {1,2}; echo foo > 2/bar

and XFS test generic/023 fail with -ENOENT error. That's why the second
mkdir reuses the existing inode (target inode of the mv -T command) with
S_DEAD flag.

Fix this by checking whether the target is directory or not and
calling cifs_rmdir() rather than cifs_unlink() for directories.

Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
Signed-off-by: Steve French <smfrench@xxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 fs/cifs/inode.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 36d2b1d6d492..2a93255c0150 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1682,7 +1682,10 @@ cifs_rename(struct inode *source_dir, struct dentry *source_dentry,
 unlink_target:
 	/* Try unlinking the target dentry if it's not negative */
 	if (target_dentry->d_inode && (rc == -EACCES || rc == -EEXIST)) {
-		tmprc = cifs_unlink(target_dir, target_dentry);
+		if (S_ISDIR(target_dentry->d_inode->i_mode))
+			tmprc = cifs_rmdir(target_dir, target_dentry);
+		else
+			tmprc = cifs_unlink(target_dir, target_dentry);
 		if (tmprc)
 			goto cifs_rename_exit;
 		rc = cifs_do_rename(xid, source_dentry, from_name,
-- 
2.1.0

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