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https://issues.apache.org/jira/browse/HDFS-13243?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16441312#comment-16441312
 ] 

Daryn Sharp commented on HDFS-13243:
------------------------------------

Maybe I overlooked some details, but please summarize the problem.  As best I 
can tell:
* thread1 is writing and closes the stream
* thread2 is syncing the stream
* thread1 calls commits the block with size 141232
* thread2 fsyncs with size 2054413
* DNs report block with size 2054413, marked corrupt

Am I wrong?  If no, how on earth can the block be committed with a size _less_ 
than a racing fsync?  This sounds like a serious client-side issue.

Agree the server-side logic needs to be improved.  Note that 
{{FileUnderConstructionFeature#updateLengthOfLastBlock}} guards against some of 
the invalid/malicious cases but unfortunately via asserts.  They don't need to 
be quasi-duplicated in this patch.

We cannot simply return success in some invalid cases: ie. fsync when the file 
has no blocks, size is negative, size is less than less synced/committed size.  
That just masks bugs.

Also, we shouldn't need all the new factories.  The tests must verify that 
namesystem calls, in various specific orders, with specific arguments that are 
good/bad, either succeed or fail.  We can't rely on the behavior of writing to 
a stream to prove the correctness of the namesystem guarding against invalid 
input from the client.

> Get CorruptBlock because of calling close and sync in same time
> ---------------------------------------------------------------
>
>                 Key: HDFS-13243
>                 URL: https://issues.apache.org/jira/browse/HDFS-13243
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: namenode
>    Affects Versions: 2.7.2, 3.2.0
>            Reporter: Zephyr Guo
>            Assignee: Zephyr Guo
>            Priority: Critical
>         Attachments: HDFS-13243-v1.patch, HDFS-13243-v2.patch, 
> HDFS-13243-v3.patch, HDFS-13243-v4.patch, HDFS-13243-v5.patch, 
> HDFS-13243-v6.patch
>
>
> HDFS File might get broken because of corrupt block(s) that could be produced 
> by calling close and sync in the same time.
> When calling close was not successful, UCBlock status would change to 
> COMMITTED, and if a sync request gets popped from queue and processed, sync 
> operation would change the last block length.
> After that, DataNode would report all received block to NameNode, and will 
> check Block length of all COMMITTED Blocks. But the block length was already 
> different between recorded in NameNode memory and reported by DataNode, and 
> consequently, the last block is marked as corruptted because of inconsistent 
> length.
>  
> {panel:title=Log in my hdfs}
> 2018-03-05 04:05:39,261 INFO org.apache.hadoop.hdfs.StateChange: BLOCK* 
> allocate blk_1085498930_11758129\{UCState=UNDER_CONSTRUCTION, 
> truncateBlock=null, primaryNodeIndex=-1, 
> replicas=[ReplicaUC[[DISK]DS-32c7e479-3845-4a44-adf1-831edec7506b:NORMAL:10.0.0.219:50010|RBW],
>  
> ReplicaUC[[DISK]DS-a9a5d653-c049-463d-8e4a-d1f0dc14409c:NORMAL:10.0.0.220:50010|RBW],
>  
> ReplicaUC[[DISK]DS-f2b7c04a-b724-4c69-abbf-d2e416f70706:NORMAL:10.0.0.218:50010|RBW]]}
>  for 
> /hbase/WALs/hb-j5e517al6xib80rkb-006.hbase.rds.aliyuncs.com,16020,1519845790686/hb-j5e517al6xib80rkb-006.hbase.rds.aliyuncs.com%2C16020%2C1519845790686.default.1520193926515
> 2018-03-05 04:05:39,760 INFO org.apache.hadoop.hdfs.StateChange: BLOCK* 
> fsync: 
> /hbase/WALs/hb-j5e517al6xib80rkb-006.hbase.rds.aliyuncs.com,16020,1519845790686/hb-j5e517al6xib80rkb-006.hbase.rds.aliyuncs.com%2C16020%2C1519845790686.default.1520193926515
>  for DFSClient_NONMAPREDUCE_1077513762_1
> 2018-03-05 04:05:39,761 INFO 
> org.apache.hadoop.hdfs.server.namenode.FSNamesystem: BLOCK* 
> blk_1085498930_11758129\{UCState=COMMITTED, truncateBlock=null, 
> primaryNodeIndex=-1, 
> replicas=[ReplicaUC[[DISK]DS-32c7e479-3845-4a44-adf1-831edec7506b:NORMAL:10.0.0.219:50010|RBW],
>  
> ReplicaUC[[DISK]DS-a9a5d653-c049-463d-8e4a-d1f0dc14409c:NORMAL:10.0.0.220:50010|RBW],
>  
> ReplicaUC[[DISK]DS-f2b7c04a-b724-4c69-abbf-d2e416f70706:NORMAL:10.0.0.218:50010|RBW]]}
>  is not COMPLETE (ucState = COMMITTED, replication# = 0 < minimum = 2) in 
> file 
> /hbase/WALs/hb-j5e517al6xib80rkb-006.hbase.rds.aliyuncs.com,16020,1519845790686/hb-j5e517al6xib80rkb-006.hbase.rds.aliyuncs.com%2C16020%2C1519845790686.default.1520193926515
> 2018-03-05 04:05:39,761 INFO BlockStateChange: BLOCK* addStoredBlock: 
> blockMap updated: 10.0.0.220:50010 is added to 
> blk_1085498930_11758129\{UCState=COMMITTED, truncateBlock=null, 
> primaryNodeIndex=-1, 
> replicas=[ReplicaUC[[DISK]DS-32c7e479-3845-4a44-adf1-831edec7506b:NORMAL:10.0.0.219:50010|RBW],
>  
> ReplicaUC[[DISK]DS-a9a5d653-c049-463d-8e4a-d1f0dc14409c:NORMAL:10.0.0.220:50010|RBW],
>  
> ReplicaUC[[DISK]DS-f2b7c04a-b724-4c69-abbf-d2e416f70706:NORMAL:10.0.0.218:50010|RBW]]}
>  size 2054413
> 2018-03-05 04:05:39,761 INFO BlockStateChange: BLOCK 
> NameSystem.addToCorruptReplicasMap: blk_1085498930 added as corrupt on 
> 10.0.0.219:50010 by 
> hb-j5e517al6xib80rkb-006.hbase.rds.aliyuncs.com/10.0.0.219 because block is 
> COMMITTED and reported length 2054413 does not match length in block map 
> 141232
> 2018-03-05 04:05:39,762 INFO BlockStateChange: BLOCK 
> NameSystem.addToCorruptReplicasMap: blk_1085498930 added as corrupt on 
> 10.0.0.218:50010 by 
> hb-j5e517al6xib80rkb-004.hbase.rds.aliyuncs.com/10.0.0.218 because block is 
> COMMITTED and reported length 2054413 does not match length in block map 
> 141232
> 2018-03-05 04:05:40,162 INFO 
> org.apache.hadoop.hdfs.server.namenode.FSNamesystem: BLOCK* 
> blk_1085498930_11758129\{UCState=COMMITTED, truncateBlock=null, 
> primaryNodeIndex=-1, 
> replicas=[ReplicaUC[[DISK]DS-32c7e479-3845-4a44-adf1-831edec7506b:NORMAL:10.0.0.219:50010|RBW],
>  
> ReplicaUC[[DISK]DS-a9a5d653-c049-463d-8e4a-d1f0dc14409c:NORMAL:10.0.0.220:50010|RBW],
>  
> ReplicaUC[[DISK]DS-f2b7c04a-b724-4c69-abbf-d2e416f70706:NORMAL:10.0.0.218:50010|RBW]]}
>  is not COMPLETE (ucState = COMMITTED, replication# = 3 >= minimum = 2) in 
> file 
> /hbase/WALs/hb-j5e517al6xib80rkb-006.hbase.rds.aliyuncs.com,16020,1519845790686/hb-j5e517al6xib80rkb-006.hbase.rds.aliyuncs.com%2C16020%2C1519845790686.default.1520193926515
> {panel}



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