code: func checkIfPathIsInAVolume(container *container.Container, absPath string) (bool, error) {
  	var toVolume bool
  	parser := volumemounts.NewParser(container.OS)
  	for _, mnt := range container.MountPoints {
  		if toVolume = parser.HasResource(mnt, absPath); toVolume {
  			if mnt.RW {
  				break
  			}
  			return false, ErrVolumeReadonly
  		}
  	}
  	return toVolume, nil
  }
docs: // checkIfPathIsInAVolume checks if the path is in a volume. If it is, it
  // cannot be in a read-only volume. If it  is not in a volume, the container
  // cannot be configured with a read-only rootfs.