'Return model update from RBD for migrated volume.
This method should rename the back-end volume name(id) on the
destination host back to its original name(id) on the source host.
:param ctxt: The context used to run the method update_migrated_volume
:param volume: The original volume that was migrated to this backend
:param new_volume: The migration volume object that was created on
this backend as part of the migration process
:param original_volume_status: The status of the original volume
:returns: model_update to update DB with any needed changes'

def update_migrated_volume(self, ctxt, volume, new_volume, original_volume_status):

    name_id = None
    provider_location = None
    existing_name = (CONF.volume_name_template % new_volume.id)
    wanted_name = (CONF.volume_name_template % volume.id)
    with RADOSClient(self) as client:
        try:
            self.RBDProxy().rename(client.ioctx, utils.convert_str(existing_name), utils.convert_str(wanted_name))
        except self.rbd.ImageNotFound:
            LOG.error('Unable    to    rename    the    logical    volume    for    volume    %s.', volume.id)
            name_id = (new_volume._name_id or new_volume.id)
            provider_location = new_volume['provider_location']
    return {'_name_id': name_id, 'provider_location': provider_location}
