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https://issues.apache.org/jira/browse/HDFS-3122?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13403169#comment-13403169
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Uma Maheswara Rao G commented on HDFS-3122:
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Hi Nicholas,
Do you have any solution for this?
One work around could be that, if reported block is having less genstamp and NN
is having higher then , how about adding them into some suspected corrupt list.
On next block report if the block is having correct genstamp(newer genstamp),
then we can just clean that block from suspectedCorruptMap. If block is having
still less genstamp and that entry already presents in suspectedCorruptMap,
then mark it as corrupt. But I am worrying to introduce one more datastructure
here.
Any suggestion on this would be appreciated.
Thanks,
Uma
> Block recovery with closeFile flag true can race with blockReport. Due to
> this blocks are getting marked as corrupt.
> --------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-3122
> URL: https://issues.apache.org/jira/browse/HDFS-3122
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: data-node, name-node
> Affects Versions: 0.23.0, 0.24.0
> Reporter: Uma Maheswara Rao G
> Assignee: Uma Maheswara Rao G
> Priority: Critical
> Attachments: blockCorrupt.txt
>
>
> *Block Report* can *race* with *Block Recovery* with closeFile flag true.
> Block report generated just before block recovery at DN side and due to N/W
> problems, block report got delayed to NN.
> After this, recovery success and generation stamp modifies to new one.
> And primary DN invokes the commitBlockSynchronization and block got updated
> in NN side. Also block got marked as complete, since the closeFile flag was
> true. Updated with new genstamp.
> Now blockReport started processing at NN side. This particular block from RBW
> (when it generated the BR at DN), and file was completed at NN side.
> Finally block will be marked as corrupt because of genstamp mismatch.
> {code}
> case RWR:
> if (!storedBlock.isComplete()) {
> return null; // not corrupt
> } else if (storedBlock.getGenerationStamp() !=
> iblk.getGenerationStamp()) {
> return new BlockToMarkCorrupt(storedBlock,
> "reported " + reportedState + " replica with genstamp " +
> iblk.getGenerationStamp() + " does not match COMPLETE block's " +
> "genstamp in block map " + storedBlock.getGenerationStamp());
> } else { // COMPLETE block, same genstamp
> {code}
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