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https://issues.apache.org/jira/browse/HDFS-8113?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14491960#comment-14491960
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Chengbing Liu commented on HDFS-8113:
-------------------------------------
The following code in {{BlockManager#processReportedBlock}} returns
{{BlockInfoContiguous}} with {{BlockCollection}} equal to {{null}}:
{code}
BlockInfoContiguous storedBlock = blocksMap.getStoredBlock(block);
{code}
There are two methods that can add entries to {{blocksMap}}:
- {{BlocksMap#addBlockCollection(BlockInfoContiguous b, BlockCollection bc)}},
we should check whether {{bc}} is {{null}}.
- {{BlocksMap#replaceBlock(BlockInfoContiguous newBlock)}}, we should check
whether {{newBlock.getBlockCollection()}} is {{null}}.
Both methods are called from many places. To get more debug information, I
think we should at least log it as WARN or ERROR if the {{BlockCollection}}
happens to be {{null}}.
> NullPointerException in BlockInfoContiguous causes block report failure
> -----------------------------------------------------------------------
>
> Key: HDFS-8113
> URL: https://issues.apache.org/jira/browse/HDFS-8113
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Affects Versions: 2.6.0
> Reporter: Chengbing Liu
> Assignee: Chengbing Liu
> Attachments: HDFS-8113.patch
>
>
> The following copy constructor can throw NullPointerException if {{bc}} is
> null.
> {code}
> protected BlockInfoContiguous(BlockInfoContiguous from) {
> this(from, from.bc.getBlockReplication());
> this.bc = from.bc;
> }
> {code}
> We have observed that some DataNodes keeps failing doing block reports with
> NameNode. The stacktrace is as follows. Though we are not using the latest
> version, the problem still exists.
> {quote}
> 2015-03-08 19:28:13,442 WARN org.apache.hadoop.hdfs.server.datanode.DataNode:
> RemoteException in offerService
> org.apache.hadoop.ipc.RemoteException(java.lang.NullPointerException):
> java.lang.NullPointerException
> at org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo.(BlockInfo.java:80)
> at
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager$BlockToMarkCorrupt.(BlockManager.java:1696)
> at
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.checkReplicaCorrupt(BlockManager.java:2185)
> at
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.processReportedBlock(BlockManager.java:2047)
> at
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.reportDiff(BlockManager.java:1950)
> at
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.processReport(BlockManager.java:1823)
> at
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.processReport(BlockManager.java:1750)
> at
> org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.blockReport(NameNodeRpcServer.java:1069)
> at
> org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolServerSideTranslatorPB.blockReport(DatanodeProtocolServerSideTranslatorPB.java:152)
> at
> org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos$DatanodeProtocolService$2.callBlockingMethod(DatanodeProtocolProtos.java:26382)
> at
> org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:587)
> at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1026)
> at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2013)
> at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2009)
> at java.security.AccessController.doPrivileged(Native Method)
> at javax.security.auth.Subject.doAs(Subject.java:415)
> at
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1623)
> at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2007)
> {quote}
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