[HDFS-15590] namenode fails to start when ordered snapshot deletion feature is disabled

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.4.0
• Component/s: snapshots
• Labels: pull-request-available
• Assignee: Shashikant Banerjee
• Reporter: Nilotpal Nandi
• Created: 22/Sep/20 05:24
• Updated: 25/Sep/20 13:33
• Resolved: 24/Sep/20 08:31

Description

1. Enabled ordered deletion snapshot feature.
2. Created snapshottable directory - /user/hrt_6/atrr_dir1
3. Created snapshots s0, s1, s2.
4. Deleted snapshot s2
5. Delete snapshot s0, s1, s2 again
6. Disable ordered deletion snapshot feature
5. Restart Namenode

Failed to start namenode.
org.apache.hadoop.hdfs.protocol.SnapshotException: Cannot delete snapshot s2 from path /user/hrt_6/atrr_dir2: the snapshot does not exist.
	at org.apache.hadoop.hdfs.server.namenode.snapshot.DirectorySnapshottableFeature.removeSnapshot(DirectorySnapshottableFeature.java:237)
	at org.apache.hadoop.hdfs.server.namenode.INodeDirectory.removeSnapshot(INodeDirectory.java:293)
	at org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotManager.deleteSnapshot(SnapshotManager.java:510)
	at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.applyEditLogOp(FSEditLogLoader.java:819)
	at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadEditRecords(FSEditLogLoader.java:287)
	at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadFSEdits(FSEditLogLoader.java:182)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:912)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:760)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:337)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFSImage(FSNamesystem.java:1164)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:755)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.loadNamesystem(NameNode.java:646)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:717)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:960)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:933)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1670)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1737)

Issue Links

• fixes: HDFS-15595 TestSnapshotCommands.testMaxSnapshotLimit fails in trunk
• links to: GitHub Pull Request #2326