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Posted to common-dev@hadoop.apache.org by "Doug Cutting (JIRA)" <ji...@apache.org> on 2006/04/18 21:20:22 UTC
[jira] Commented: (HADOOP-139) Deadlock in LocalFileSystem
lock/release
[ http://issues.apache.org/jira/browse/HADOOP-139?page=comments#action_12374983 ]
Doug Cutting commented on HADOOP-139:
-------------------------------------
I just committed this. Thanks, Igor!
The patch did not apply directly, due to other changes made to Hadoop since you contributed it. So I had to apply parts of it manually. Please check that it still looks correct. Thanks!
> Deadlock in LocalFileSystem lock/release
> ----------------------------------------
>
> Key: HADOOP-139
> URL: http://issues.apache.org/jira/browse/HADOOP-139
> Project: Hadoop
> Type: Bug
> Components: fs
> Reporter: Igor Bolotin
> Attachments: deadlock.patch
>
> LocalFileSystem lock/release methods marked synchronized and inside they lock file channel - this produces deadlock situation. Let's see how it happens:
> 1. First thread locks the file and starts some long-running process.
> 2. Second thread tries to lock the file and it blocks inside channel lock method. It keeps LocalFileSystem instance "locked" as well.
> 3. First thread finished it's processing and tries to release lock - it blocks because LocalFileSystem instance is "locked" by second thread - both threads are waiting to each other.
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