'Brings an existing storage object under Cinder management.'

@cinder_utils.synchronized('manage_existing')
def manage_existing(self, volume, existing_ref):

    vol = self._get_existing_vol_with_manage_ref(existing_ref)
    label = utils.convert_uuid_to_es_fmt(volume['id'])
    if (label == vol['label']):
        LOG.info('Volume    with    given    ref    %s    need    not    be    renamed    during    manage    operation.', existing_ref)
        managed_vol = vol
    else:
        managed_vol = self._client.update_volume(vol['id'], label)
    LOG.info('Manage    operation    completed    for    volume    with    new    label    %(label)s    and    wwn    %(wwn)s.', {'label': label, 'wwn': managed_vol[self.WORLDWIDENAME]})
