Xiaoyu Yao created HDFS-13120:
---------------------------------

             Summary: Snapshot diff could be corrupted after concat
                 Key: HDFS-13120
                 URL: https://issues.apache.org/jira/browse/HDFS-13120
             Project: Hadoop HDFS
          Issue Type: Bug
          Components: namenode, snapshots
            Reporter: Xiaoyu Yao
            Assignee: Xiaoyu Yao


The snapshot diff can be corrupted after concat files. This could lead to 
Assertion upon DeleteSnapshot and getSnapshotDiff operations later. 

For example, we have seen customers hit stack trace similar to the one below 
but during loading edit entry of DeleteSnapshotOp. After the investigation, we 
found this is a regression caused by HDFS-3689 where the snapshot diff is not 
fully cleaned up after concat. 

I will post the unit test to repro this and fix for it shortly.

{code}
org.apache.hadoop.ipc.RemoteException(java.lang.AssertionError): Element 
already exists: element=0.txt, CREATED=[0.txt, 1.txt, 2.txt]
        at org.apache.hadoop.hdfs.util.Diff.insert(Diff.java:196)
        at org.apache.hadoop.hdfs.util.Diff.create(Diff.java:216)
        at org.apache.hadoop.hdfs.util.Diff.combinePosterior(Diff.java:463)
        at 
org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature$DirectoryDiff.combinePosteriorAndCollectBlocks(DirectoryWithSnapshotFeature.java:205)
        at 
org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature$DirectoryDiff.combinePosteriorAndCollectBlocks(DirectoryWithSnapshotFeature.java:162)
        at 
org.apache.hadoop.hdfs.server.namenode.snapshot.AbstractINodeDiffList.deleteSnapshotDiff(AbstractINodeDiffList.java:100)
        at 
org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature.cleanDirectory(DirectoryWithSnapshotFeature.java:728)
        at 
org.apache.hadoop.hdfs.server.namenode.INodeDirectory.cleanSubtree(INodeDirectory.java:830)
        at 
org.apache.hadoop.hdfs.server.namenode.snapshot.DirectorySnapshottableFeature.removeSnapshot(DirectorySnapshottableFeature.java:237)
        at 
org.apache.hadoop.hdfs.server.namenode.INodeDirectory.removeSnapshot(INodeDirectory.java:292)
        at 
org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotManager.deleteSnapshot(SnapshotManager.java:321)
        at 
org.apache.hadoop.hdfs.server.namenode.FSDirSnapshotOp.deleteSnapshot(FSDirSnapshotOp.java:249)
        at 
org.apache.hadoop.hdfs.server.namenode.FSNamesystem.deleteSnapshot(FSNamesystem.java:6566)
        at 
org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.deleteSnapshot(NameNodeRpcServer.java:1823)
        at 
org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.deleteSnapshot(ClientNamenodeProtocolServerSideTranslatorPB.java:1200)
        at 
org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
        at 
org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:524)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1007)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:873)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:819)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at 
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1965)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2679)

{code} 





--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org

Reply via email to