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https://issues.apache.org/jira/browse/HDFS-14941?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16966376#comment-16966376
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Hadoop QA commented on HDFS-14941:
----------------------------------

| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue}  0m 
50s{color} | {color:blue} Docker mode activated. {color} |
|| || || || {color:brown} Prechecks {color} ||
| {color:green}+1{color} | {color:green} @author {color} | {color:green}  0m  
0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green}  0m 
 0s{color} | {color:green} The patch appears to include 2 new or modified test 
files. {color} |
|| || || || {color:brown} trunk Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue}  1m 
11s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 19m 
37s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 16m 
13s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green}  2m 
42s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green}  2m 
32s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} shadedclient {color} | {color:green} 
18m 51s{color} | {color:green} branch has no errors when building and testing 
our client artifacts. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green}  4m  
6s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green}  2m 
50s{color} | {color:green} trunk passed {color} |
|| || || || {color:brown} Patch Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue}  0m 
58s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green}  1m 
47s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 15m 
36s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 15m 
36s{color} | {color:green} the patch passed {color} |
| {color:orange}-0{color} | {color:orange} checkstyle {color} | {color:orange}  
2m 42s{color} | {color:orange} root: The patch generated 2 new + 542 unchanged 
- 1 fixed = 544 total (was 543) {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green}  2m 
26s{color} | {color:green} the patch passed {color} |
| {color:red}-1{color} | {color:red} whitespace {color} | {color:red}  0m  
1s{color} | {color:red} The patch has 2 line(s) that end in whitespace. Use git 
apply --whitespace=fix <<patch_file>>. Refer https://git-scm.com/docs/git-apply 
{color} |
| {color:green}+1{color} | {color:green} shadedclient {color} | {color:green} 
13m  5s{color} | {color:green} patch has no errors when building and testing 
our client artifacts. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green}  4m 
18s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green}  2m 
43s{color} | {color:green} the patch passed {color} |
|| || || || {color:brown} Other Tests {color} ||
| {color:red}-1{color} | {color:red} unit {color} | {color:red}  8m 34s{color} 
| {color:red} hadoop-common in the patch failed. {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red}103m 29s{color} 
| {color:red} hadoop-hdfs in the patch failed. {color} |
| {color:red}-1{color} | {color:red} asflicense {color} | {color:red}  0m 
48s{color} | {color:red} The patch generated 1 ASF License warnings. {color} |
| {color:black}{color} | {color:black} {color} | {color:black}223m 16s{color} | 
{color:black} {color} |
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|| Reason || Tests ||
| Failed junit tests | hadoop.conf.TestCommonConfigurationFields |
|   | hadoop.hdfs.TestDFSInotifyEventInputStreamKerberized |
|   | hadoop.hdfs.tools.TestDFSZKFailoverController |
|   | hadoop.hdfs.TestDecommissionWithStriped |
|   | hadoop.hdfs.server.namenode.ha.TestPipelinesFailover |
|   | hadoop.hdfs.server.namenode.TestRedudantBlocks |
|   | hadoop.hdfs.server.namenode.ha.TestAddBlockTailing |
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|| Subsystem || Report/Notes ||
| Docker | Client=19.03.4 Server=19.03.4 Image:yetus/hadoop:104ccca9169 |
| JIRA Issue | HDFS-14941 |
| JIRA Patch URL | 
https://issues.apache.org/jira/secure/attachment/12984743/HDFS-14941.001.patch |
| Optional Tests |  dupname  asflicense  compile  javac  javadoc  mvninstall  
mvnsite  unit  shadedclient  findbugs  checkstyle  |
| uname | Linux 6e796882e44f 4.15.0-66-generic #75-Ubuntu SMP Tue Oct 1 
05:24:09 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/patchprocess/precommit/personality/provided.sh |
| git revision | trunk / d462308 |
| maven | version: Apache Maven 3.3.9 |
| Default Java | 1.8.0_222 |
| findbugs | v3.1.0-RC1 |
| checkstyle | 
https://builds.apache.org/job/PreCommit-HDFS-Build/28236/artifact/out/diff-checkstyle-root.txt
 |
| whitespace | 
https://builds.apache.org/job/PreCommit-HDFS-Build/28236/artifact/out/whitespace-eol.txt
 |
| unit | 
https://builds.apache.org/job/PreCommit-HDFS-Build/28236/artifact/out/patch-unit-hadoop-common-project_hadoop-common.txt
 |
| unit | 
https://builds.apache.org/job/PreCommit-HDFS-Build/28236/artifact/out/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt
 |
|  Test Results | 
https://builds.apache.org/job/PreCommit-HDFS-Build/28236/testReport/ |
| asflicense | 
https://builds.apache.org/job/PreCommit-HDFS-Build/28236/artifact/out/patch-asflicense-problems.txt
 |
| Max. process+thread count | 2770 (vs. ulimit of 5500) |
| modules | C: hadoop-common-project/hadoop-common 
hadoop-hdfs-project/hadoop-hdfs U: . |
| Console output | 
https://builds.apache.org/job/PreCommit-HDFS-Build/28236/console |
| Powered by | Apache Yetus 0.8.0   http://yetus.apache.org |


This message was automatically generated.



> Potential editlog race condition can cause corrupted file
> ---------------------------------------------------------
>
>                 Key: HDFS-14941
>                 URL: https://issues.apache.org/jira/browse/HDFS-14941
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: namenode
>            Reporter: Chen Liang
>            Assignee: Chen Liang
>            Priority: Major
>              Labels: ha
>         Attachments: HDFS-14941.001.patch
>
>
> Recently we encountered an issue that, after a failover, NameNode complains 
> corrupted file/missing blocks. The blocks did recover after full block 
> reports, so the blocks are not actually missing. After further investigation, 
> we believe this is what happened:
> First of all, on SbN, it is possible that it receives block reports before 
> corresponding edit tailing happened. In which case SbN postpones processing 
> the DN block report, handled by the guarding logic below:
> {code:java}
>       if (shouldPostponeBlocksFromFuture &&
>           namesystem.isGenStampInFuture(iblk)) {
>         queueReportedBlock(storageInfo, iblk, reportedState,
>             QUEUE_REASON_FUTURE_GENSTAMP);
>         continue;
>       }
> {code}
> Basically if reported block has a future generation stamp, the DN report gets 
> requeued.
> However, in {{FSNamesystem#storeAllocatedBlock}}, we have the following code:
> {code:java}
>       // allocate new block, record block locations in INode.
>       newBlock = createNewBlock();
>       INodesInPath inodesInPath = INodesInPath.fromINode(pendingFile);
>       saveAllocatedBlock(src, inodesInPath, newBlock, targets);
>       persistNewBlock(src, pendingFile);
>       offset = pendingFile.computeFileSize();
> {code}
> The line
>  {{newBlock = createNewBlock();}}
>  Would log an edit entry {{OP_SET_GENSTAMP_V2}} to bump generation stamp on 
> Standby
>  while the following line
>  {{persistNewBlock(src, pendingFile);}}
>  would log another edit entry {{OP_ADD_BLOCK}} to actually add the block on 
> Standby.
> Then the race condition is that, imagine Standby has just processed 
> {{OP_SET_GENSTAMP_V2}}, but not yet {{OP_ADD_BLOCK}} (if they just happen to 
> be in different setment). Now a block report with new generation stamp comes 
> in.
> Since the genstamp bump has already been processed, the reported block may 
> not be considered as future block. So the guarding logic passes. But 
> actually, the block hasn't been added to blockmap, because the second edit is 
> yet to be tailed. So, the block then gets added to invalidate block list and 
> we saw messages like:
> {code:java}
> BLOCK* addBlock: block XXX on node XXX size XXX does not belong to any file
> {code}
> Even worse, since this IBR is effectively lost, the NameNode has no 
> information about this block, until the next full block report. So after a 
> failover, the NN marks it as corrupt.
> This issue won't happen though, if both of the edit entries get tailed all 
> together, so no IBR processing can happen in between. But in our case, we set 
> edit tailing interval to super low (to allow Standby read), so when under 
> high workload, there is a much much higher chance that the two entries are 
> tailed separately, causing the issue.



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