code: func (m *execMounter) Unmount(target string) error {
  	outputBytes, err := m.exec.Run("umount", target)
  	if err == nil {
  		klog.V(5).Infof("Exec unmounted %s: %s", target, string(outputBytes))
  	} else {
  		klog.V(5).Infof("Failed to exec unmount %s: err: %q, umount output: %s", target, err, string(outputBytes))
  	}
  
  	return err
  }
docs: // Unmount runs umount(8) using given exec interface.