Implements hook_field_insert().
function file_field_insert($entity_type, $entity, $field, $instance, $langcode, &$items) {
list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);
// Add a new usage of each uploaded file.
foreach ($items as $item) {
$file = (object) $item;
file_usage_add($file, 'file', $entity_type, $id);
}
}