code: func GetInTreePluginNameFromSpec(pv *v1.PersistentVolume, vol *v1.Volume) (string, error) {
  	if pv != nil {
  		for _, curPlugin := range inTreePlugins {
  			if curPlugin.CanSupport(pv) {
  				return curPlugin.GetInTreePluginName(), nil
  			}
  		}
  		return "", fmt.Errorf("could not find in-tree plugin name from persistent volume %v", pv)
  	} else if vol != nil {
  		// TODO(dyzz): Implement inline volume migration support
  		return "", errors.New("inline volume migration not yet supported")
  	} else {
  		return "", errors.New("both persistent volume and volume are nil")
  	}
  }
docs: // GetInTreePluginNameFromSpec returns the plugin name