private ProcedureWALFile initOldLog(final FileStatus logFile, final Path walArchiveDir)
    throws IOException {
    final ProcedureWALFile log = new ProcedureWALFile(fs, logFile);
    if (logFile.getLen() == 0) {
      LOG.warn("Remove uninitialized log: {}", logFile);
      log.removeFile(walArchiveDir);
      return null;
    }
    LOG.debug("Opening Pv2 {}", logFile);
    try {
      log.open();
    } catch (ProcedureWALFormat.InvalidWALDataException e) {
      LOG.warn("Remove uninitialized log: {}", logFile, e);
      log.removeFile(walArchiveDir);
      return null;
    } catch (IOException e) {
      String msg = "Unable to read state log: " + logFile;
      LOG.error(msg, e);
      throw new IOException(msg, e);
    }

    try {
      log.readTracker();
    } catch (IOException e) {
      log.getTracker().reset();
      log.getTracker().setPartialFlag(true);
      LOG.warn("Unable to read tracker for {}", log, e);
    }

    log.close();
    return log;
  }
Loads given log file and it's tracker.
hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/store/wal/WALProcedureStore.java