code: func (cfg *MountCfg) Opts() string {
  	opts := fmt.Sprintf(
  		"lowerdir=%s,upperdir=%s,workdir=%s",
  		sanitize(cfg.Lower), sanitize(cfg.Upper), sanitize(cfg.Work),
  	)
  
  	return label.FormatMountLabel(opts, cfg.Lbl)
  }
docs: // Opts returns options for mount system call.