ovl: disable decoding null uuid with redirect_dir

Currently decoding origin with lower null uuid is not allowed unless user
opted-in to one of the new features that require following the lower inode
of non-dir upper (index, xino, metacopy). Now we add redirect_dir too to
that feature list.
Signed-off-by: Vyacheslav Yurkov <Vyacheslav.Yurkov@bruker.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/super.c

@@ -1600,7 +1600,7 @@ static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid)
 	 * lower inode of non-dir upper.
 	 */
 	if (!ofs->config.index && !ofs->config.metacopy &&
-	    ofs->config.xino != OVL_XINO_ON &&
+	    !ofs->config.redirect_dir && ofs->config.xino != OVL_XINO_ON &&
 	    uuid_is_null(uuid))
 		return false;