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https://issues.apache.org/jira/browse/HDFS-16214?focusedWorklogId=738022&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-738022
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ASF GitHub Bot logged work on HDFS-16214:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 08/Mar/22 08:40
Start Date: 08/Mar/22 08:40
Worklog Time Spent: 10m
Work Description: zhuxiangyi commented on a change in pull request #3885:
URL: https://github.com/apache/hadoop/pull/3885#discussion_r821437088
##########
File path:
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirDeleteOp.java
##########
@@ -112,10 +110,76 @@ static BlocksMapUpdateInfo delete(
}
DFSUtil.checkProtectedDescendants(fsd, iip);
}
-
return deleteInternal(fsn, iip, logRetryCache);
}
+ /**
+ * Clean files and update Quota after collecting blcoks.
+ * <p>
+ * When it takes a long time to collect blocks when encountering
+ * a large directory, the collection block here adopts no lock。
+ * <p>
+ *
+ * @param fsn namespace
+ * @param iip inodes of a path to be deleted
+ * @return blocks collected from the deleted path
+ * @throws IOException
+ */
+ static BlocksMapUpdateInfo clearFileAndUpdateQuota(FSNamesystem fsn,
INodesInPath iip)
+ throws QuotaExceededException {
+ long filesRemoved = -1;
+ if (iip == null) {
+ return null;
+ }
+ // collect blocks no lock
+ INode.ReclaimContext context = FSDirDeleteOp.collectBlocks(fsn, iip);
+ filesRemoved = context.quotaDelta().getNsDelta();
+ if (filesRemoved < 0) {
+ return context.collectedBlocks;
+ }
+ // update Quota and clear UCFiles lease
+ fsn.writeLock();
+ try {
+ FSDirectory fsd = fsn.getFSDirectory();
+ fsd.removeInodeFromDeletingInodes(iip.getLastINode());
+ fsn.removeLeasesAndINodes(context.removedUCFiles,
+ context.removedINodes, true);
+ fsd.updateCount(iip, context.quotaDelta(), false);
+ incrDeletedFileCount(filesRemoved);
+
fsd.updateReplicationFactor(context.collectedBlocks().toUpdateReplicationInfo());
+ } finally {
+ fsn.writeUnlock();
+ }
+ return context.collectedBlocks;
+ }
+
+ /**
+ * Collect blocks from the deleted path.
+ *
+ * @param fsn namespace
+ * @param iip inodes of a path to be deleted
+ * @return blocks collected from the deleted path
+ */
+ static ReclaimContext collectBlocks(FSNamesystem fsn, INodesInPath iip) {
Review comment:
There may be problems in deleting the snapshot file without locking. I
reconstructed the logic of this part, put the deletion of the snapshot file
into the lock, and use asynchronous collection block and update quota.
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Issue Time Tracking
-------------------
Worklog Id: (was: 738022)
Time Spent: 50m (was: 40m)
> Asynchronously collect blocks and update quota when deleting
> ------------------------------------------------------------
>
> Key: HDFS-16214
> URL: https://issues.apache.org/jira/browse/HDFS-16214
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode
> Affects Versions: 3.4.0
> Reporter: Xiangyi Zhu
> Assignee: Xiangyi Zhu
> Priority: Major
> Labels: pull-request-available
> Time Spent: 50m
> Remaining Estimate: 0h
>
> The time-consuming deletion is mainly reflected in three logics , collecting
> blocks, deleting Inode from InodeMap, and deleting blocks. The current
> deletion is divided into two major steps. Step 1 acquires the lock, collects
> the block and inode, deletes the inode, and releases the lock. Step 2 Acquire
> the lock and delete the block to release the lock.
> Phase 2 is currently deleting blocks in batches, which can control the lock
> holding time. Here we can also delete blocks asynchronously.
> Now step 1 still has the problem of holding the lock for a long time.
> For stage 1, we can make the collection block not hold the lock. The process
> is as follows, step 1 obtains the lock, parent.removeChild, writes to
> editLog, releases the lock. Step 2 no lock, collects the block. Step 3
> acquire lock, update quota, release lease, release lock. Step 4 acquire lock,
> delete Inode from InodeMap, release lock. Step 5 acquire lock, delete block
> to release lock.
> There may be some problems following the above process:
> 1. When the /a/b/c file is writing, then delete the /a/b directory. If the
> deletion is performed to the collecting block stage, the client writes
> complete or addBlock to the /a/b/c file at this time. This step is not locked
> and delete /a/b and editLog has been written successfully. In this case, the
> order of editLog is delete /a/c and complete /a/b/c. In this case, the
> standby node playback editLog /a/b/c file has been deleted, and then go to
> complete /a/b/c file will be abnormal.
> *The process is as follows:*
> *write editLog order: delete /a/b/c -> delete /a/b -> complete /a/b/c*
> *replay editLog order:* *delete /a/b/c ->* *delete /a/b ->* *complete /a/b/c
> {color:#ff0000}(not found){color}*
> 2. If a delete operation is executed to the stage of collecting block, then
> the administrator executes saveNameSpace, and then restarts Namenode. This
> situation may cause the Inode that has been deleted from the parent childList
> to remain in the InodeMap.
> To solve the above problem, in step 1, add the inode being deleted to the
> Set. When there is a file WriteFileOp (logAllocateBlockId/logCloseFile
> EditLog), check whether there is this file and one of its parent Inodes in
> the Set, and throw it if there is. An exception FileNotFoundException
> occurred.
> In addition, the execution of saveNamespace needs to wait for all iNodes in
> Set to be removed before execution.
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