code: func (handler *deviceHandler) FindMultipathDeviceForDevice(device string) string {
  	io := handler.getIo
  	disk, err := findDeviceForPath(device, io)
  	if err != nil {
  		return ""
  	}
  	sysPath := "/sys/block/"
  	if dirs, err := io.ReadDir(sysPath); err == nil {
  		for _, f := range dirs {
  			name := f.Name()
  			if strings.HasPrefix(name, "dm-") {
  				if _, err1 := io.Lstat(sysPath + name + "/slaves/" + disk); err1 == nil {
  					return "/dev/" + name
  				}
  			}
  		}
  	}
  	return ""
  }
docs: // FindMultipathDeviceForDevice given a device name like /dev/sdx, find the devicemapper parent