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From "Uma Maheswara Rao G (Updated) (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HDFS-3122) Block recovery with closeFile flag true can race with blockReport. Due to this blocks are getting marked as corrupt.
Date Wed, 21 Mar 2012 05:43:42 GMT

     [ https://issues.apache.org/jira/browse/HDFS-3122?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Uma Maheswara Rao G updated HDFS-3122:
--------------------------------------

         Description: 
*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}






  was:
*Block Report* can *race* with *Block Recovery* with closeFile flag true.

 IF block report generated just befor recovery at DN side and due to N/W. This block report
got delayed to NN. Recovery success and generation stamp has been changed to new one. 
primary DN invokes the commitBlockSynchronization and block got updated in NN side. Also marked
as complete, since the closeFile flag is 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.

Since the genartion stamps are mismatching, block is getting marked as corrupt.

{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}






    Target Version/s: 0.24.0, 0.23.3  (was: 0.23.3, 0.24.0)
    
> 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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