protected void treeWriteLock()

in hbase-oss/src/main/java/org/apache/hadoop/hbase/oss/sync/TreeLockManager.java [265:305]
36 lines of code
11 McCabe index (conditional complexity)

  protected void treeWriteLock(Path path, Depth depth) throws IOException {
    int outerRetries = 0;
    long outerInitAttempt = System.currentTimeMillis();
    do {
      int innerRetries = 0;
      long innerInitAttempt = System.currentTimeMillis();
      do {
        // If there's already a write-lock above or below us in the tree, wait for it to leave
        if (writeLockAbove(path) || writeLockBelow(path, depth)) {
          if (this.warnIfAboveThreshold(innerInitAttempt,
            "Blocked on some parent write lock, waiting: {}", path.toString())) {
            innerInitAttempt = System.currentTimeMillis();
          }
          continue;
        }
        break;
      } while (retryBackoff(innerRetries++));
      // Try obtain the write lock just for our node
      writeLock(path);
      // If there's now a write-lock above or below us in the tree, release and retry
      if (writeLockAbove(path) || writeLockBelow(path, depth)) {
        if (this.warnIfAboveThreshold(outerInitAttempt,
          "Blocked on some other write lock, retrying: {}", path.toString())) {
          outerInitAttempt = System.currentTimeMillis();
        }
        writeUnlock(path);
        continue;
      }
      break;
    } while (retryBackoff(outerRetries++));

    // Once we know we're the only write-lock in our path, drain all read-locks below
    int drainReadLocksRetries = 0;
    do {
      if (readLockBelow(path, depth)) {
        LOG.warn("Blocked on some child read lock, writing: {}", path);
        continue;
      }
      break;
    } while (retryBackoff(drainReadLocksRetries++));
  }