'Create an attachment record for the specified volume.'

@wrap_check_policy
def attachment_create(self, ctxt, volume_ref, instance_uuid, connector=None):

    connection_info = {}
    attachment_ref = self._attachment_reserve(ctxt, volume_ref, instance_uuid)
    if connector:
        connection_info = self.volume_rpcapi.attachment_update(ctxt, volume_ref, connector, attachment_ref.id)
    attachment_ref.connection_info = connection_info
    attachment_ref.save()
    return attachment_ref
