code: func (h *fs) Chmod(file string, mode os.FileMode) error {
  	err := os.Chmod(file, mode)
  	if runtime.GOOS == "windows" && err == nil {
  		h.m.Lock()
  		h.fileModes[file] = mode
  		h.m.Unlock()
  		return nil
  	}
  	return err
  }
docs: // Chmod sets the file mode