[HDFS-16099] Make bpServiceToActive to be volatile

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.4.0
• Component/s: datanode
• Labels: pull-request-available
• Hadoop Flags: Reviewed
• Assignee: Shuyan Zhang
• Reporter: Shuyan Zhang
• Created: 30/Jun/21 06:23
• Updated: 01/Jul/21 15:54
• Resolved: 01/Jul/21 15:54

Description

BPOfferService#bpServiceToActive is not volatile, which may cause CommandProcessingThread to get the out-of-date active namenode.
When a failover occurs, the old ANN's CommandProcessingThread may read the outdated BPOfferService#bpServiceToActive and execute the NN's command. At this time, if the new ANN's CommandProcessingThread reads the new value of bpServiceToActive, split brain will occur; otherwise, the new ANN's commands cannot be executed normally, which is also unacceptable.

Issue Links

• links to: GitHub Pull Request #3159