func createBlockMetadata(mds torus.MetadataService, name string, vid torus.VolumeID) (blockMetadata, error) {
	switch mds.Kind() {
	case torus.EtcdMetadata:
		return createBlockEtcdMetadata(mds, name, vid)
	case torus.TempMetadata:
		return createBlockTempMetadata(mds, name, vid)
	default:
		return nil, errors.New("unimplemented for this kind of metadata")
	}
}