CIFS: Fix directory rename error

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@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 36d2b1d6d492d4fc06d5b45748fc34b486f851fc..2a93255c01508aa9e20f409b818de9e8e338eb31 100644 (file)
--- 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,