From: Jeff Layton <jlayton@redhat.com>
Date: Mon, 14 Jun 2010 13:20:25 -0400
Subject: [fs] cifs: don't try busy-file rename unless in same dir
Message-id: <1276521625-26149-1-git-send-email-jlayton@redhat.com>
Patchwork-id: 26114
O-Subject: [RHEL5.6 PATCH] BZ#603706: cifs: don't attempt busy-file rename
	unless it's in same directory
Bugzilla: 603706
RH-Acked-by: Steve Dickson <SteveD@redhat.com>

Older windows SMB servers typically refuse to allow files that are open
to be renamed as the underlying filesystem doesn't support it. If you
rename by filehandle however, you can generally rename files as long as
that doesn't cross directories.

The CIFS code is set up to try to rename by filehandle when renaming
by name fails, but it doesn't properly limit that code to renames
within the same directory. When that is attempted, the file is generally
renamed to the target name, but stays within the same directory.

The following patch is being pushed upstream for 2.6.35 and into stable
trees. It just prevents the busy-file rename code from being attempted
when the source and target have different parent directories.

----------------------[snip]---------------------

Busy-file renames don't actually work across directories, so we need
to limit this code to renames within the same dir.

This fixes the bug detailed here:

    https://bugzilla.redhat.com/show_bug.cgi?id=591938

Signed-off-by: Jeff Layton <jlayton@redhat.com>
CC: Stable <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 2e61150..10754a1 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1358,6 +1358,10 @@ cifs_do_rename(int xid, struct dentry *from_dentry, const char *fromPath,
 	if (rc == 0 || rc != -ETXTBSY)
 		return rc;
 
+	/* open-file renames don't work across directories */
+	if (to_dentry->d_parent != from_dentry->d_parent)
+		return rc;
+
 	/* open the file to be renamed -- we need DELETE perms */
 	rc = CIFSSMBOpen(xid, pTcon, fromPath, FILE_OPEN, DELETE,
 			 CREATE_NOT_DIR, &srcfid, &oplock, NULL,