'Retrieve stats info from volume group.'

def _update_volume_stats(self):

    super(NfsDriver, self)._update_volume_stats()
    self._stats['sparse_copy_volume'] = True
    data = self._stats
    global_capacity = data['total_capacity_gb']
    global_free = data['free_capacity_gb']
    thin_enabled = self.configuration.nfs_sparsed_volumes
    if thin_enabled:
        provisioned_capacity = self._get_provisioned_capacity()
    else:
        provisioned_capacity = round((global_capacity - global_free), 2)
    data['provisioned_capacity_gb'] = provisioned_capacity
    data['max_over_subscription_ratio'] = self.max_over_subscription_ratio
    data['reserved_percentage'] = self.reserved_percentage
    data['thin_provisioning_support'] = thin_enabled
    data['thick_provisioning_support'] = (not thin_enabled)
    self._stats = data
