private function notify_failure(stdClass $info, $reason = '') {
        $filedesc = $this->describe_alias($info);
        if ($reason) {
            $reason = ' ('.$reason.')';
        }
        $this->log('unable to restore alias'.$reason, backup::LOG_WARNING, $filedesc, 1);
        $this->add_result_item('file_aliases_restore_failures', $filedesc);
    }