code: func (daemon *Daemon) Unmount(container *container.Container) error {
  	if container.RWLayer == nil {
  		return errors.New("RWLayer of container " + container.ID + " is unexpectedly nil")
  	}
  	if err := container.RWLayer.Unmount(); err != nil {
  		logrus.Errorf("Error unmounting container %s: %s", container.ID, err)
  		return err
  	}
  
  	return nil
  }
docs: // Unmount unsets the container base filesystem