[HDFS-16764] ObserverNamenode handles addBlock rpc and throws a FileNotFoundException

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.4.0, 3.3.6
• Fix Version/s: 3.4.0, 3.3.6
• Component/s: namenode
• Labels: pull-request-available
• Target Version/s: 3.4.0, 3.3.6
• Hadoop Flags: Reviewed
• Assignee: ZanderXu
• Reporter: ZanderXu
• Created: 08/Sep/22 03:26
• Updated: 16/Oct/24 18:29
• Resolved: 17/Jan/23 13:53

Description

ObserverNameNode currently can handle the addBlockLocation RPC, but it may throw a FileNotFoundException when it contains stale txid.

• AddBlock is not a coordinated method, so Observer will not check the statId.
• AddBlock does the validation with checkOperation(OperationCategory.READ)

So the observer can handle the addBlock rpc. If this observer cannot replay the edit of create file, it will throw a FileNotFoundException during doing validation.

The related code as follows:

checkOperation(OperationCategory.READ);
final FSPermissionChecker pc = getPermissionChecker();
FSPermissionChecker.setOperationType(operationName);
readLock();
try {
  checkOperation(OperationCategory.READ);
  r = FSDirWriteFileOp.validateAddBlock(this, pc, src, fileId, clientName,
                                        previous, onRetryBlock);
} finally {
  readUnlock(operationName);
} 

Issue Links

• links to: GitHub Pull Request #4872