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https://issues.apache.org/jira/browse/HDFS-7587?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jing Zhao updated HDFS-7587:
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    Attachment: HDFS-7587.003.patch

Thanks for the review, Nicholas! Update the patch to address your comments. I 
will separate the truncate fix into another jira.

bq. Non-copy-on-truncate OR Copy-on-truncate for upgrade but not snapshot: 
Quota usage count is decreased. No quota check is needed.

We may also need to check/update the quota here since the current logic is to 
count UC block's storage usage using the preferred size.

> Edit log corruption can happen if append fails with a quota violation
> ---------------------------------------------------------------------
>
>                 Key: HDFS-7587
>                 URL: https://issues.apache.org/jira/browse/HDFS-7587
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: namenode
>            Reporter: Kihwal Lee
>            Assignee: Jing Zhao
>            Priority: Blocker
>         Attachments: HDFS-7587.001.patch, HDFS-7587.002.patch, 
> HDFS-7587.003.patch, HDFS-7587.patch
>
>
> We have seen a standby namenode crashing due to edit log corruption. It was 
> complaining that {{OP_CLOSE}} cannot be applied because the file is not 
> under-construction.
> When a client was trying to append to the file, the remaining space quota was 
> very small. This caused a failure in {{prepareFileForWrite()}}, but after the 
> inode was already converted for writing and a lease added. Since these were 
> not undone when the quota violation was detected, the file was left in 
> under-construction with an active lease without edit logging {{OP_ADD}}.
> A subsequent {{append()}} eventually caused a lease recovery after the soft 
> limit period. This resulted in {{commitBlockSynchronization()}}, which closed 
> the file with {{OP_CLOSE}} being logged.  Since there was no corresponding 
> {{OP_ADD}}, edit replaying could not apply this.



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