public function validation($data, $files) {
        $errors = array();
        $draftitemid = $data['files_filemanager'];
        if (file_is_draft_area_limit_reached($draftitemid, $this->_customdata['options']['areamaxbytes'])) {
            $errors['files_filemanager'] = get_string('userquotalimit', 'error');
        }

        return $errors;
    }