[HDFS-1263] 0.20: in tryUpdateBlock, the meta file is renamed away before genstamp validation is done

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 0.20-append
• Fix Version/s: 0.20-append
• Component/s: datanode
• Assignee: Todd Lipcon
• Reporter: Todd Lipcon
• Created: 23/Jun/10 08:10
• Updated: 24/Jun/10 13:47
• Resolved: 24/Jun/10 13:47

Description

Saw an issue where multiple datanodes are trying to recover at the same time, and all of them failed. I think the issue is in FSDataset.tryUpdateBlock, we do the rename of blk_B_OldGS to blk_B_OldGS_tmpNewGS and then check that the generation stamp is moving upwards. Because of this, invalid update block calls are blocked, but they then cause future updateBlock calls to fail with "Meta file not found" errors.

Issue Links

• is related to: HDFS-1225 Block lost when primary crashes in recoverBlock
• relates to: HDFS-1260 0.20: Block lost when multiple DNs trying to recover it to different genstamps