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https://issues.apache.org/jira/browse/HDFS-6527?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14046194#comment-14046194
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Aaron T. Myers commented on HDFS-6527:
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bq. In the meanwhile, in FSNamesystem#delete, maybe we should move
"dir.removeFromInodeMap(removedINodes)" into the fsnamesystem write lock? I
guess this will prevent similar issue in the future.
This currently is done under the write lock, but it's done after having dropped
the write lock briefly, so presumably you're proposing to make all of the
contents of {{deleteInternal}} happen under a single write lock? That seems
reasonable to me, but to be honest I'm not sure of the history of why this
deferred inode removal was done in the first place.
> Edit log corruption due to defered INode removal
> ------------------------------------------------
>
> Key: HDFS-6527
> URL: https://issues.apache.org/jira/browse/HDFS-6527
> Project: Hadoop HDFS
> Issue Type: Bug
> Affects Versions: 2.4.0
> Reporter: Kihwal Lee
> Assignee: Kihwal Lee
> Priority: Blocker
> Fix For: 3.0.0, 2.5.0
>
> Attachments: HDFS-6527-addendum-test.patch,
> HDFS-6527.branch-2.4.patch, HDFS-6527.trunk.patch, HDFS-6527.v2.patch,
> HDFS-6527.v3.patch, HDFS-6527.v4.patch, HDFS-6527.v5.patch
>
>
> We have seen a SBN crashing with the following error:
> {panel}
> \[Edit log tailer\] ERROR namenode.FSEditLogLoader:
> Encountered exception on operation AddBlockOp
> [path=/xxx,
> penultimateBlock=NULL, lastBlock=blk_111_111, RpcClientId=,
> RpcCallId=-2]
> java.io.FileNotFoundException: File does not exist: /xxx
> {panel}
> This was caused by the deferred removal of deleted inodes from the inode map.
> Since getAdditionalBlock() acquires FSN read lock and then write lock, a
> deletion can happen in between. Because of deferred inode removal outside FSN
> write lock, getAdditionalBlock() can get the deleted inode from the inode map
> with FSN write lock held. This allow addition of a block to a deleted file.
> As a result, the edit log will contain OP_ADD, OP_DELETE, followed by
> OP_ADD_BLOCK. This cannot be replayed by NN, so NN doesn't start up or SBN
> crashes.
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