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https://issues.apache.org/jira/browse/HDFS-6618?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14049195#comment-14049195
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Kihwal Lee edited comment on HDFS-6618 at 7/1/14 7:06 PM:
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bq. can we move the following code into the writelock of FSNamesystem in
deleteInternal?
That can degrade performance when deleting a large tree. I also got worried
about similar kind of race during rename and others.
was (Author: kihwal):
bq. can we move the following code into the writelock of FSNamesystem in
deleteInternal?
That can degrade performance when deleting a large tree.
> Edit log corruption may still happen even after HDFS-6527
> ---------------------------------------------------------
>
> Key: HDFS-6618
> URL: https://issues.apache.org/jira/browse/HDFS-6618
> Project: Hadoop HDFS
> Issue Type: Bug
> Affects Versions: 2.5.0
> Reporter: Kihwal Lee
> Priority: Blocker
> Attachments: HDFS-6618.patch
>
>
> After HDFS-6527, we have not seen the edit log corruption for weeks on
> multiple clusters until yesterday. Previously, we would see it within 30
> minutes on a cluster.
> But the same condition was reproduced even with HDFS-6527. The only
> explanation is that the RPC handler thread serving {{addBlock()}} was
> accessing stale parent value. Although nulling out parent is done inside the
> {{FSNamesystem}} and {{FSDirectory}} write lock, there is no memory barrier
> because there is no "synchronized" block involved in the process.
> I suggest making parent volatile.
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