code: func (rbd *rbd) GetGlobalMapPath(spec *volume.Spec) (string, error) {
  	return rbd.rbdGlobalMapPath(spec)
  }
docs: // GetGlobalMapPath returns global map path and error
  // path: plugins/kubernetes.io/{PluginName}/volumeDevices/{rbd pool}-image-{rbd image-name}/{podUid}