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https://issues.apache.org/jira/browse/HDFS-2791?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13192778#comment-13192778
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Todd Lipcon commented on HDFS-2791:
-----------------------------------
>> Case 2) if the block has the correct generation stamp, ignore it (don't add
>> to block locations or mark it corrupt)
> This looks ok at first sight. If the generation stamp and length matches with
> what the NN has is it safe to add it to the blocksmap?
Yes, I think so. I had originally thought about doing that, but ATM convinced
me otherwise - our thinking is now that this case only occurs because of a
temporary delay in transmission of the "correct" state. So we'll always expect
to see the FINALIZED report come in soon after one of these RBW replicas. Given
that, I think it is simpler/safer to ignore it in all cases.
> If block report races with closing of file, replica is incorrectly marked
> corrupt
> ---------------------------------------------------------------------------------
>
> Key: HDFS-2791
> URL: https://issues.apache.org/jira/browse/HDFS-2791
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: data-node, name-node
> Affects Versions: 0.22.0, 0.23.0
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Attachments: hdfs-2791-test.txt, hdfs-2791.txt, hdfs-2791.txt,
> hdfs-2791.txt
>
>
> The following sequence of events results in a replica mistakenly marked
> corrupt:
> 1. Pipeline is open with 2 replicas
> 2. DN1 generates a block report but is slow in sending to the NN (eg some
> flaky network). It gets "stuck" right before the block report RPC.
> 3. Client closes the file.
> 4. DN2 is fast and sends blockReceived to the NN. NN marks the block as
> COMPLETE
> 5. DN1's block report proceeds, and includes the block in an RBW state.
> 6. (x) NN incorrectly marks the replica as corrupt, since it is an RBW
> replica on a COMPLETE block.
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