func getVolumeDeviceDataDir(specVolID string, host volume.VolumeHost) string {
	return filepath.Join(getVolumePluginDir(specVolID, host), "data")
}

// hasReadWriteOnce returns true if modes contains v1.ReadWriteOnce
func hasReadWriteOnce(modes []api.PersistentVolumeAccessMode) bool {
	if modes == nil {
		return false
	}
	for _, mode := range modes {
		if mode == api.ReadWriteOnce {
			return true
		}

	if c.spec.PersistentVolume != nil {
		if c.spec.PersistentVolume.Spec.AccessModes == nil {
			klog.V(4).Info(log("mounter.SetupAt WARNING: skipping fsGroup, access modes not provided"))
			return false
		}
		if !hasReadWriteOnce(c.spec.PersistentVolume.Spec.AccessModes) {
			klog.V(4).Info(log("mounter.SetupAt WARNING: skipping fsGroup, only support ReadWriteOnce access mode"))
			return false
		}
		return true