code: static public boolean metaFileExists(FSDatasetInterface dataset, int namespaceId, Block b) throws IOException {
      return getMetaFile(dataset, namespaceId, b).exists();
    }
docs: Does the meta file exist for this block?
  @param namespaceId - parent namespace id
  @param b - the block
  @return true of the metafile for specified block exits
  @throws IOException