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https://issues.apache.org/jira/browse/HADOOP-1513?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12508243
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Raghu Angadi commented on HADOOP-1513:
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Actually it should just be {{'if (!mkdirsWithExistsCheck()) { throw ...'}}.
Also could you explicitly note in the comment that this implementation is a
modification of Sun's File.mkdirs() implementation.
> A likely race condition between the creation of a directory and checking for
> its existence in the DiskChecker class
> -------------------------------------------------------------------------------------------------------------------
>
> Key: HADOOP-1513
> URL: https://issues.apache.org/jira/browse/HADOOP-1513
> Project: Hadoop
> Issue Type: Bug
> Components: fs
> Affects Versions: 0.14.0
> Reporter: Devaraj Das
> Assignee: Devaraj Das
> Priority: Critical
> Fix For: 0.14.0
>
> Attachments: 1513.patch, 1513.patch
>
>
> Got this exception in a job run. It looks like the problem is a race
> condition between the creation of a directory and checking for its existence.
> Specifically, the line:
> if (!dir.exists() && !dir.mkdirs()), doesn't seem safe when invoked by
> multiple processes at the same time.
> 2007-06-21 07:55:33,583 INFO org.apache.hadoop.mapred.MapTask:
> numReduceTasks: 1
> 2007-06-21 07:55:33,818 WARN org.apache.hadoop.fs.AllocatorPerContext:
> org.apache.hadoop.util.DiskChecker$DiskErrorException: can not create
> directory: /export/crawlspace/kryptonite/ddas/dfs/data/tmp
> at org.apache.hadoop.util.DiskChecker.checkDir(DiskChecker.java:26)
> at
> org.apache.hadoop.fs.LocalDirAllocator$AllocatorPerContext.createPath(LocalDirAllocator.java:211)
> at
> org.apache.hadoop.fs.LocalDirAllocator$AllocatorPerContext.getLocalPathForWrite(LocalDirAllocator.java:248)
> at
> org.apache.hadoop.fs.LocalDirAllocator$AllocatorPerContext.createTmpFileForWrite(LocalDirAllocator.java:276)
> at
> org.apache.hadoop.fs.LocalDirAllocator.createTmpFileForWrite(LocalDirAllocator.java:155)
> at
> org.apache.hadoop.dfs.DFSClient$DFSOutputStream.newBackupFile(DFSClient.java:1171)
> at org.apache.hadoop.dfs.DFSClient$DFSOutputStream.(DFSClient.java:1136)
> at org.apache.hadoop.dfs.DFSClient.create(DFSClient.java:342)
> at
> org.apache.hadoop.dfs.DistributedFileSystem$RawDistributedFileSystem.create(DistributedFileSystem.java:145)
> at
> org.apache.hadoop.fs.ChecksumFileSystem$FSOutputSummer.(ChecksumFileSystem.java:368)
> at
> org.apache.hadoop.fs.ChecksumFileSystem.create(ChecksumFileSystem.java:443)
> at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:254)
> at org.apache.hadoop.io.SequenceFile$Writer.(SequenceFile.java:675)
> at org.apache.hadoop.io.SequenceFile.createWriter(SequenceFile.java:165)
> at
> org.apache.hadoop.examples.RandomWriter$Map.map(RandomWriter.java:137)
> at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:46)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:189)
> at
> org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java:1740)
> 2007-06-21 07:55:33,821 WARN org.apache.hadoop.mapred.TaskTracker: Error
> running child
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