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https://issues.apache.org/jira/browse/HDFS-7707?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vinod Kumar Vavilapalli updated HDFS-7707:
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    Fix Version/s: 2.6.1

[~sjlee0] backported this to 2.6.1. I just pushed the commit to 2.6.1 after 
running compilation and TestCommitBlockSynchronization, TestDeleteRace which 
changed in the patch.


> Edit log corruption due to delayed block removal again
> ------------------------------------------------------
>
>                 Key: HDFS-7707
>                 URL: https://issues.apache.org/jira/browse/HDFS-7707
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: namenode
>    Affects Versions: 2.6.0
>            Reporter: Yongjun Zhang
>            Assignee: Yongjun Zhang
>              Labels: 2.6.1-candidate
>             Fix For: 2.7.0, 2.6.1
>
>         Attachments: HDFS-7707.001.patch, HDFS-7707.002.patch, 
> HDFS-7707.003.patch, reproduceHDFS-7707.patch
>
>
> Edit log corruption is seen again, even with the fix of HDFS-6825. 
> Prior to HDFS-6825 fix, if dirX is deleted recursively, an OP_CLOSE can get 
> into edit log for the fileY under dirX, thus corrupting the edit log 
> (restarting NN with the edit log would fail). 
> What HDFS-6825 does to fix this issue is, to detect whether fileY is already 
> deleted by checking the ancestor dirs on it's path, if any of them doesn't 
> exist, then fileY is already deleted, and don't put OP_CLOSE to edit log for 
> the file.
> For this new edit log corruption, what I found was, the client first deleted 
> dirX recursively, then create another dir with exactly the same name as dirX 
> right away.  Because HDFS-6825 count on the namespace checking (whether dirX 
> exists in its parent dir) to decide whether a file has been deleted, the 
> newly created dirX defeats this checking, thus OP_CLOSE for the already 
> deleted file gets into the edit log, due to delayed block removal.
> What we need to do is to have a more robust way to detect whether a file has 
> been deleted.



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