'Retrieve stats info from filer.'

def _update_volume_stats(self, filter_function=None, goodness_function=None):

    self.vol_refresh_voluntary = True
    self._refresh_volume_info()
    LOG.debug('Updating    volume    stats')
    data = {}
    backend_name = self.configuration.safe_get('volume_backend_name')
    data['volume_backend_name'] = (backend_name or self.driver_name)
    data['vendor_name'] = 'NetApp'
    data['driver_version'] = self.VERSION
    data['storage_protocol'] = self.driver_protocol
    data['pools'] = self._get_pool_stats(filter_function=filter_function, goodness_function=goodness_function)
    data['sparse_copy_volume'] = True
    self._stats = data
