[XFS] Fix hang after disallowed rename across directory quota domains

When project quota is active and is being used for directory tree
quota control, we disallow rename outside the current directory
tree. This requires a check to be made after all the inodes
involved in the rename are locked. We fail to unlock the inodes
correctly if we disallow the rename when the target is outside the
current directory tree. This results in a hang on the next access
to the inodes involved in failed rename.
Reported-by: Arkadiusz Miskiewicz <arekm@maven.pl>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Tested-by: Arkadiusz Miskiewicz <arekm@maven.pl>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

fs/xfs/xfs_rename.c

@@ -212,7 +212,7 @@ xfs_rename(
 	if (unlikely((target_dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
 		     (target_dp->i_d.di_projid != src_ip->i_d.di_projid))) {
 		error = XFS_ERROR(EXDEV);
-		xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
+		xfs_rename_unlock4(inodes, XFS_ILOCK_EXCL);
 		xfs_trans_cancel(tp, cancel_flags);
 		goto std_return;
 	}