btrfs_rename() does not release the subvol_sem if the transaction failed to start.
Signed-off-by: Johann Lombardi <johann@whamcloud.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
         * should cover the worst case number of items we'll modify.
         */
        trans = btrfs_start_transaction(root, 20);
-       if (IS_ERR(trans))
-               return PTR_ERR(trans);
+       if (IS_ERR(trans)) {
+                ret = PTR_ERR(trans);
+                goto out_notrans;
+        }
 
        btrfs_set_trans_block_group(trans, new_dir);
 
        }
 out_fail:
        btrfs_end_transaction_throttle(trans, root);
-
+out_notrans:
        if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
                up_read(&root->fs_info->subvol_sem);