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https://issues.apache.org/jira/browse/HDFS-16804?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17627109#comment-17627109
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ASF GitHub Bot commented on HDFS-16804:
---------------------------------------

Hexiaoqiao commented on code in PR #5033:
URL: https://github.com/apache/hadoop/pull/5033#discussion_r1010316878


##########
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java:
##########
@@ -452,6 +449,9 @@ private synchronized void activateVolume(
       throw new IOException(errorMsg);
     }
     volumeMap.mergeAll(replicaMap);
+    for (String bp : volumeMap.getBlockPoolList()) {

Review Comment:
   Could `storageMap` meet some concurrent-modify issues when move hold lock 
logic here? Thanks.





> AddVolume contains a race condition with shutdown block pool
> ------------------------------------------------------------
>
>                 Key: HDFS-16804
>                 URL: https://issues.apache.org/jira/browse/HDFS-16804
>             Project: Hadoop HDFS
>          Issue Type: Bug
>            Reporter: ZanderXu
>            Assignee: ZanderXu
>            Priority: Major
>              Labels: pull-request-available
>
> Add Volume contains a race condition with shutdown block pool, causing the 
> ReplicaMap still contains some blocks belong to the removed block pool.
> And the new volume still contains one unused BlockPoolSlice belongs to the 
> removed block pool, caused some problems, such as: incorrect dfsUsed, 
> incorrect numBlocks of the volume.
> Let's review the logic of addVolume and shutdownBlockPool respectively.
>  
> AddVolume Logic:
>  * Step1: Get all namespaceInfo from blockPoolManager
>  * Step2: Create one temporary FsVolumeImpl object
>  * Step3: Create some blockPoolSlice according to the namespaceInfo and add 
> them to the temporary FsVolumeImpl object
>  * Step4: Scan all blocks of the namespaceInfo from the volume and store them 
> by one temporary ReplicaMap
>  * Step5: Active the temporary FsVolumeImpl which created before (with 
> FsDatasetImpl synchronized lock)
>  ** Step5.1: Merge all blocks of the temporary ReplicaMap to the global 
> ReplicaMap
>  ** Step5.2: Add the FsVolumeImpl to the volumes
> ShutdownBlockPool Logic:(with blockPool write lock)
>  * Step1: Cleanup the blockPool from the global ReplicaMap
>  * Step2: Shutdown the block pool from all the volumes
>  ** Step2.1: do some clean operations for the block pool, such as 
> saveReplica, saveDfsUsed, etc
>  ** Step2.2: remove the blockPool from bpSlices
> The race condition can be reproduced by the following steps:
>  * AddVolume Step1: Get all namespaceInfo from blockPoolManager
>  * ShutdownBlockPool Step1: Cleanup the blockPool from the global ReplicaMap
>  * ShutdownBlockPool Step2: Shutdown the block pool from all the volumes
>  * AddVolume Step 2~5
> And result:
>  * The global replicaMap contains some blocks belong to the removed blockPool
>  * The bpSlices of the FsVolumeImpl contains one blockPoolSlice belong to the 
> removed blockPool
> Expected result:
>  * The global replicaMap shouldn't contain any blocks belong to the removed 
> blockPool
>  * The bpSlices of any FsVolumeImpl shouldn't contain any blockPoolSlice 
> belong to the removed blockPool



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