code: func (m *csiBlockMapper) GetGlobalMapPath(spec *volume.Spec) (string, error) {
  	dir := getVolumeDevicePluginDir(spec.Name(), m.plugin.host)
  	klog.V(4).Infof(log("blockMapper.GetGlobalMapPath = %s", dir))
  	return dir, nil
  }
docs: // GetGlobalMapPath returns a global map path (on the node) to a device file which will be symlinked to
  // Example: plugins/kubernetes.io/csi/volumeDevices/{pvname}/dev