code: func loadVolumeData(dir string, fileName string) (map[string]string, error) {
  	// remove /mount at the end
  	dataFileName := filepath.Join(dir, fileName)
  	klog.V(4).Info(log("loading volume data file [%s]", dataFileName))
  
  	file, err := os.Open(dataFileName)
  	if err != nil {
  		klog.Error(log("failed to open volume data file [%s]: %v", dataFileName, err))
  		return nil, err
  	}
  	defer file.Close()
  	data := map[string]string{}
  	if err := json.NewDecoder(file).Decode(&data); err != nil {
  		klog.Error(log("failed to parse volume data file [%s]: %v", dataFileName, err))
  		return nil, err
  	}
  
  	return data, nil
  }
docs: // loadVolumeData loads volume info from specified json file/location