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https://issues.apache.org/jira/browse/HDFS-7611?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14292454#comment-14292454
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Jing Zhao commented on HDFS-7611:
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Thanks for digging into the issue, [~Byron Wong]!
So currently we have two ways to fix the issue:
# While applying the editlog, instead of calling {{INode#addSpaceConsumed}}, we
should use {{FSDirectory#updateCount}} which checks if image/editlog has been
loaded.
# We do not compute quota change and update quota usage in
{{FSDirectory#removeLastINode}} anymore. Instead, we move the quota
computation/update part to its caller. In this way, the quota usage change,
even if it's wrong, will not affect the real deletion.
Both changes actually are necessary. But #1 requires a lot of code refactoring.
Since #2 alone can also fix the reported bug, I guess we can do #1 in a
separate jira.
> deleteSnapshot and delete of a file can leave orphaned blocks in the
> blocksMap on NameNode restart.
> ---------------------------------------------------------------------------------------------------
>
> Key: HDFS-7611
> URL: https://issues.apache.org/jira/browse/HDFS-7611
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Affects Versions: 2.6.0
> Reporter: Konstantin Shvachko
> Assignee: Byron Wong
> Priority: Critical
> Attachments: blocksNotDeletedTest.patch, testTruncateEditLogLoad.log
>
>
> If quotas are enabled a combination of operations *deleteSnapshot* and
> *delete* of a file can leave orphaned blocks in the blocksMap on NameNode
> restart. They are counted as missing on the NameNode, and can prevent
> NameNode from coming out of safeMode and could cause memory leak during
> startup.
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