code: public static GenStampAndChecksum getGenStampAndChecksumFromInlineChecksumFile(
        String fileName) throws IOException {
      String[] vals = StringUtils.split(fileName, '_');
      if (vals.length != 6) {
        // blk, blkid, genstamp, version, checksumtype, byte per checksum
        throw new IOException("unidentified block name format: " + fileName);
      }
      if (Integer.parseInt(vals[3]) != FSDataset.FORMAT_VERSION_INLINECHECKSUM) {
        // We only support one version of meta version now.
        throw new IOException("Unsupported format version for file "
            + fileName);
  
      }
      return new GenStampAndChecksum(Long.parseLong(vals[2]),
              Integer.parseInt(vals[4]), Integer.parseInt(vals[5]));
    }
docs: Return the generation stamp from the name of the block file.