code: func makeVDPDNameInternal(host volume.VolumeHost, pool string, image string) string {
  	return filepath.Join(host.GetVolumeDevicePluginDir(rbdPluginName), pool+"-image-"+image)
  }
docs: // Make a directory like /var/lib/kubelet/plugins/kubernetes.io/rbd/volumeDevices/pool-image-image.