'Run a single pass of the image cache manager.'

@periodic_task.periodic_task(spacing=CONF.image_cache_manager_interval, external_process_ok=True)
def _run_image_cache_manager_pass(self, context):

    if (not self.driver.capabilities['has_imagecache']):
        return
    storage_users.register_storage_use(CONF.instances_path, CONF.host)
    nodes = storage_users.get_storage_users(CONF.instances_path)
    filters = {'deleted': False, 'soft_deleted': True, 'host': nodes}
    filtered_instances = objects.InstanceList.get_by_filters(context, filters, expected_attrs=[], use_slave=True)
    self.driver.manage_image_cache(context, filtered_instances)
