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https://issues.apache.org/jira/browse/HDFS-13846?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16595669#comment-16595669
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Daniel Templeton commented on HDFS-13846:
-----------------------------------------
Great catch. Thanks for the patch. Here are some comments:
# In {{BlockManagerSafeMode.decrementSafeBlockCount()}} the javadoc says it
will, "decrement number of safe blocks if current block has fallen below
minimal replication," but the conditional only tests for equality:
{code:java}
blockManager.countNodes(b).liveReplicas() == safe - 1{code}
Which one is wrong?
# In {{BlockManagerSafeMode.decrementSafeBlockCount()}} I don't like the name
{{safe}}. I see you copied it from another method, but it sounds like a
boolean. Can you give it a name that's more obvious as to what it is?
# In {{BlockManagerSafeMode.assertSafeModeIsLeftAtThreshold()}}, please add
messages to the asserts.
Otherwise, looks good.
> Safe blocks counter is not decremented correctly if the block is striped
> ------------------------------------------------------------------------
>
> Key: HDFS-13846
> URL: https://issues.apache.org/jira/browse/HDFS-13846
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs
> Affects Versions: 3.1.0
> Reporter: Kitti Nanasi
> Assignee: Kitti Nanasi
> Priority: Major
> Attachments: HDFS-13846.001.patch, HDFS-13846.002.patch
>
>
> In BlockManagerSafeMode class, the "safe blocks" counter is incremented if
> the number of nodes containing the block equals to the number of data units
> specified by the erasure coding policy, which looks like this in the code:
> {code:java}
> final int safe = storedBlock.isStriped() ?
> ((BlockInfoStriped)storedBlock).getRealDataBlockNum() :
> safeReplication;
> if (storageNum == safe) {
> this.blockSafe++;
> {code}
> But when it is decremented the code does not check if the block is striped or
> not, just compares the number of nodes containing the block with 0
> (safeReplication - 1) if the block is complete, which is not correct.
> {code:java}
> if (storedBlock.isComplete() &&
> blockManager.countNodes(b).liveReplicas() == safeReplication - 1) {
> this.blockSafe--;
> assert blockSafe >= 0;
> checkSafeMode();
> }
> {code}
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