[HDFS-14843] Double Synchronization in BlockReportLeaseManager

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.3.0
• Hadoop Flags: Reviewed
• Assignee: David Mollitor
• Reporter: David Mollitor
• Created: 11/Sep/19 01:19
• Updated: 24/Sep/19 17:25
• Resolved: 24/Sep/19 16:58

Description

BlockReportLeaseManager.java

  private synchronized long getNextId() {
    long id;
    do {
      id = nextId++;
    } while (id == 0);
    return id;
  }

This is a private method and is synchronized, however, it is only be accessed from an already-synchronized method. No need to double-synchronize.

https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockReportLeaseManager.java#L183-L189

https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockReportLeaseManager.java#L227