'The DotHill requires a volume to be dettached to clone it.
Make sure that the volume is not in use when trying to copy it.'

def _assert_source_detached(self, volume):

    if ((volume['status'] != 'available') or (volume['attach_status'] == fields.VolumeAttachStatus.ATTACHED)):
        LOG.error('Volume    must    be    detached    for    clone    operation.')
        raise exception.VolumeAttached(volume_id=volume['id'])
