code: func GetFSMagic(rootpath string) (FsMagic, error) {
  	var buf unix.Statfs_t
  	if err := unix.Statfs(rootpath, &buf); err != nil {
  		return 0, err
  	}
  	return FsMagic(buf.Type), nil
  }
docs: // GetFSMagic returns the filesystem id given the path.