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https://issues.apache.org/jira/browse/HDFS-10348?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Rushabh S Shah updated HDFS-10348:
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Attachment: HDFS-10348-1.patch
> Namenode report bad block method doesn't check whether the block belongs to
> datanode before adding it to corrupt replicas map.
> ------------------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-10348
> URL: https://issues.apache.org/jira/browse/HDFS-10348
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Affects Versions: 2.7.0
> Reporter: Rushabh S Shah
> Assignee: Rushabh S Shah
> Attachments: HDFS-10348-1.patch, HDFS-10348.patch
>
>
> Namenode (via report bad block nethod) doesn't check whether the block
> belongs to the datanode before it adds to corrupt replicas map.
> In one of our cluster we found that there were 3 lingering corrupt blocks.
> It happened in the following order.
> 1. Two clients called getBlockLocations for a particular file.
> 2. Client C1 tried to open the file and encountered checksum error from
> node N3 and it reported bad block (blk1) to the namenode.
> 3. Namenode added that node N3 and block blk1 to corrrupt replicas map and
> ask one of the good node (one of the 2 nodes) to replicate the block to
> another node N4.
> 4. After receiving the block, N4 sends an IBR (with RECEIVED_BLOCK) to
> namenode.
> 5. Namenode removed the block and node N3 from corrupt replicas map.
> It also removed N3's storage from triplets and queued an invalidate
> request for N3.
> 6. In the mean time, Client C2 tries to open the file and the request went to
> node N3.
> C2 also encountered the checksum exception and reported bad block to
> namenode.
> 7. Namenode added the corrupt block blk1 and node N3 to the corrupt replicas
> map without confirming whether node N3 has the block or not.
> After deleting the block, N3 sends an IBR (with DELETED) and the namenode
> simply ignores the report since the N3's storage is no longer in the
> triplets(from step 5)
> We took the node out of rotation, but still the block was present only in the
> corruptReplciasMap.
> Since on removing the node, we only goes through the block which are present
> in the triplets for a given datanode.
> [~kshukla]'s patch fixed this bug via
> https://issues.apache.org/jira/browse/HDFS-9958.
> But I think the following check should be made in the
> BlockManager#markBlockAsCorrupt instead of
> BlockManager#findAndMarkBlockAsCorrupt.
> {noformat}
> if (storage == null) {
> storage = storedBlock.findStorageInfo(node);
> }
> if (storage == null) {
> blockLog.debug("BLOCK* findAndMarkBlockAsCorrupt: {} not found on {}",
> blk, dn);
> return;
> }
> {noformat}
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