code: protected void setStorageType(Properties props, StorageDirectory sd)
        throws InconsistentFSStateException {
      NodeType type = NodeType.valueOf(getProperty(props, sd, STORAGE_TYPE));
      if (!storageType.equals(type)) {
        throw new InconsistentFSStateException(sd.root,
            "node type is incompatible with others.");
      }
      storageType = type;
    }
docs: Validate and set storage type from {@link Properties}