code: func NewOptionsForDriver(spec *volume.Spec, host volume.VolumeHost, extraOptions map[string]string) (OptionsForDriver, error) {
  
  	volSourceFSType, err := getFSType(spec)
  	if err != nil {
  		return nil, err
  	}
  
  	readOnly, err := getReadOnly(spec)
  	if err != nil {
  		return nil, err
  	}
  
  	volSourceOptions, err := getOptions(spec)
  	if err != nil {
  		return nil, err
  	}
  
  	options := map[string]string{}
  
  	options[optionFSType] = volSourceFSType
  
  	if readOnly {
  		options[optionReadWrite] = "ro"
  	} else {
  		options[optionReadWrite] = "rw"
  	}
  
  	options[optionPVorVolumeName] = spec.Name()
  
  	for key, value := range extraOptions {
  		options[key] = value
  	}
  
  	for key, value := range volSourceOptions {
  		options[key] = value
  	}
  
  	return OptionsForDriver(options), nil
  }
docs: // NewOptionsForDriver create driver options given volume spec