'Driver entry point to increase the size of a volume.'

def extend_volume(self, volume, new_size):

    extra_specs = na_utils.get_volume_extra_specs(volume)
    volume_copy = copy.copy(volume)
    volume_copy['size'] = new_size
    qos_policy_group_info = self._setup_qos_for_volume(volume_copy, extra_specs)
    qos_policy_group_name = na_utils.get_qos_policy_group_name_from_info(qos_policy_group_info)
    try:
        self._extend_volume(volume, new_size, qos_policy_group_name)
    except Exception:
        with excutils.save_and_reraise_exception():
            self._setup_qos_for_volume(volume, extra_specs)
