'Fail back all the volume on the secondary backend.'

def _replication_failback(self, ctxt, volumes):

    volumes_update = []
    if (not self._active_backend_id):
        LOG.info("Host    has    been    failed    back.    doesn't    need    to    fail    back    again")
        return (None, volumes_update)
    try:
        self._master_backend_helpers.get_system_info()
    except Exception:
        msg = _('Unable    to    failback    due    to    primary    is    not    reachable.')
        LOG.error(msg)
        raise exception.UnableToFailOver(reason=msg)
    (unrep_volumes, rep_volumes) = self._classify_volume(ctxt, volumes)
    self._sync_with_aux(ctxt, rep_volumes)
    self._wait_replica_ready(ctxt, rep_volumes)
    rep_volumes_update = self._failback_replica_volumes(ctxt, rep_volumes)
    volumes_update.extend(rep_volumes_update)
    unrep_volumes_update = self._failover_unreplicated_volume(unrep_volumes)
    volumes_update.extend(unrep_volumes_update)
    self._helpers = self._master_backend_helpers
    self._active_backend_id = None
    self._update_storwize_state()
    self._update_volume_stats()
    return (storwize_const.FAILBACK_VALUE, volumes_update)
