code: func findDeviceForPath(path string, io IoUtil) (string, error) {
  	devicePath, err := io.EvalSymlinks(path)
  	if err != nil {
  		return "", err
  	}
  	// if path /dev/hdX split into "", "dev", "hdX" then we will
  	// return just the last part
  	parts := strings.Split(devicePath, "/")
  	if len(parts) == 3 && strings.HasPrefix(parts[1], "dev") {
  		return parts[2], nil
  	}
  	return "", errors.New("Illegal path for device " + devicePath)
  }
docs: // findDeviceForPath Find the underlaying disk for a linked path such as /dev/disk/by-path/XXXX or /dev/mapper/XXXX
  // will return sdX or hdX etc, if /dev/sdX is passed in then sdX will be returned