code: protected void setLayoutVersion(Properties props, StorageDirectory sd)
        throws IncorrectVersionException, InconsistentFSStateException {
      int lv = Integer.parseInt(getProperty(props, sd, LAYOUT_VERSION));
      if (lv < FSConstants.LAYOUT_VERSION) { // future version
        throw new IncorrectVersionException(lv, "storage directory "
            + sd.root.getAbsolutePath());
      }
      layoutVersion = lv;
    }
docs: Validate and set layout version from {@link Properties}