code: func (plugin *vsphereVolumePlugin) GetDeviceMountRefs(deviceMountPath string) ([]string, error) {
  	mounter := plugin.host.GetMounter(plugin.GetPluginName())
  	return mounter.GetMountRefs(deviceMountPath)
  }
docs: // GetMountDeviceRefs finds all other references to the device referenced
  // by deviceMountPath; returns a list of paths.