public void stampedReadUnlock(long stamp) {
    lock.lock();
    try {
      if (readCnt.containsKey(stamp)) {
        if (readCnt.get(stamp) == 1) {
          readCnt.remove(stamp);
          if (readCnt.isEmpty() && writeWait > 0) {
            // no reader, then signal all writer
            okToWrite.signalAll();
          }
        } else {
          readCnt.put(stamp, readCnt.get(stamp) - 1);
        }
      }
    } finally {
      lock.unlock();
    }
  }
Attempts to release stamp-bound read lock.

@param stamp read lock stamp
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/pbtree/lock/StampedWriterPreferredLock.java