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https://issues.apache.org/jira/browse/HDFS-5657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13846807#comment-13846807
]
Jing Zhao commented on HDFS-5657:
---------------------------------
The solution looks good to me. Some comments:
# The writeAsync method can be deleted instead of commented out.
{code}
+/* void writeAsync(OpenFileCtx openFileCtx) {
if (LOG.isDebugEnabled()) {
LOG.debug("Scheduling write back task for fileId: "
+ openFileCtx.getLatestAttr().getFileId());
@@ -103,7 +103,7 @@ void writeAsync(OpenFileCtx openFileCtx) {
WriteBackTask wbTask = new WriteBackTask(openFileCtx);
execute(wbTask);
}
-
+*/
{code}
# The following section is very similar with the checkAndStartWrite method. You
may want to modify checkAndStartWrite and try to reuse it here.
{code}
+ if (!pendingWrites.isEmpty()
+ && pendingWrites.firstKey().getMin() == nextOffset.get()) {
+ LOG.info("Race happened: a sequential write was just added."
+ + " Start another async task.");
+ asyncStatus = true;
+ try {
+ ads.execute(new AsyncDataService.WriteBackTask(this, ads));
+ } catch (Throwable t) {
+ activeState = false;
+ // Can't set asyncStatus to false since task might be in queue
+ LOG.error("Can't reinvoke async task, fileId=" + fileId, t);
+ }
+ }
{code}
> race condition causes writeback state error in NFS gateway
> ----------------------------------------------------------
>
> Key: HDFS-5657
> URL: https://issues.apache.org/jira/browse/HDFS-5657
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: nfs
> Reporter: Brandon Li
> Assignee: Brandon Li
> Attachments: HDFS-5657.001.patch, HDFS-5657.002.patch
>
>
> A race condition between NFS gateway writeback executor thread and new write
> handler thread can cause writeback state check failure, e.g.,
> {noformat}
> 2013-11-26 10:34:07,859 DEBUG nfs3.RpcProgramNfs3
> (Nfs3Utils.java:writeChannel(113)) - WRITE_RPC_CALL_END______957880843
> 2013-11-26 10:34:07,863 DEBUG nfs3.OpenFileCtx
> (OpenFileCtx.java:offerNextToWrite(832)) - The asyn write task has no pending
> writes, fileId: 30938
> 2013-11-26 10:34:07,871 ERROR nfs3.AsyncDataService
> (AsyncDataService.java:run(136)) - Asyn data service got
> error:java.lang.IllegalStateException: The openFileCtx has false async status
> at
> com.google.common.base.Preconditions.checkState(Preconditions.java:145)
> at
> org.apache.hadoop.hdfs.nfs.nfs3.OpenFileCtx.executeWriteBack(OpenFileCtx.java:890)
> at
> org.apache.hadoop.hdfs.nfs.nfs3.AsyncDataService$WriteBackTask.run(AsyncDataService.java:134)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:662)
> 2013-11-26 10:34:07,901 DEBUG nfs3.RpcProgramNfs3
> (RpcProgramNfs3.java:write(707)) - requesed offset=917504 and current
> filesize=917504
> 2013-11-26 10:34:07,902 DEBUG nfs3.WriteManager
> (WriteManager.java:handleWrite(131)) - handleWrite fileId: 30938 offset:
> 917504 length:65536 stableHow:0
> {noformat}
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