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https://issues.apache.org/jira/browse/HDFS-6577?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Arpit Agarwal resolved HDFS-6577.
---------------------------------
Resolution: Not a Problem
Resolving, feel free to respond if you disagree.
> Failure to create FinalizeCommand
> ---------------------------------
>
> Key: HDFS-6577
> URL: https://issues.apache.org/jira/browse/HDFS-6577
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Affects Versions: 2.4.0
> Reporter: Yongjun Zhang
> Assignee: Yongjun Zhang
>
> I visually see a bug in NameNodeRpcServer.java,
> {code}
> @Override // DatanodeProtocol
> public DatanodeCommand blockReport(DatanodeRegistration nodeReg,
> String poolId, StorageBlockReport[] reports) throws IOException {
> verifyRequest(nodeReg);
> if(blockStateChangeLog.isDebugEnabled()) {
> blockStateChangeLog.debug("*BLOCK* NameNode.blockReport: "
> + "from " + nodeReg + ", reports.length=" + reports.length);
> }
> final BlockManager bm = namesystem.getBlockManager();
> boolean noStaleStorages = false;
> for(StorageBlockReport r : reports) {
> final BlockListAsLongs blocks = new BlockListAsLongs(r.getBlocks());
> noStaleStorages = bm.processReport(nodeReg, r.getStorage(), poolId,
> blocks);
> metrics.incrStorageBlockReportOps();
> }
> if (nn.getFSImage().isUpgradeFinalized() &&
> !nn.isStandbyState() &&
> noStaleStorages) {
> return new FinalizeCommand(poolId);
> }
> return null;
> }
> {code}
> noStaleStorage is initialized to false, then in the for loop {{
> for(StorageBlockReport r : reports) {}} it could be changed to true.
> The problem is, since it's a loop of all reports, the value returned from the
> last blockreport (the last iteration) will set it to the final value. Even if
> it was set to true in the middle of a loop, the final iteration could
> overwrite it to false. Similarly, if it was set to false in the middle, and
> the final iter could overwrite it to true.
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