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https://issues.apache.org/jira/browse/HDFS-16214?focusedWorklogId=723426&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-723426
 ]

ASF GitHub Bot logged work on HDFS-16214:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 09/Feb/22 03:29
            Start Date: 09/Feb/22 03:29
    Worklog Time Spent: 10m 
      Work Description: jojochuang commented on a change in pull request #3885:
URL: https://github.com/apache/hadoop/pull/3885#discussion_r801406046



##########
File path: 
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirDeleteOp.java
##########
@@ -88,19 +88,17 @@ static long delete(FSDirectory fsd, INodesInPath iip,
    * @param recursive boolean true to apply to all sub-directories recursively
    * @param logRetryCache whether to record RPC ids in editlog for retry cache
    *          rebuilding
-   * @return blocks collected from the deleted path
    * @throws IOException
    */
-  static BlocksMapUpdateInfo delete(
+  static boolean delete(
       FSNamesystem fsn, FSPermissionChecker pc, String src, boolean recursive,
-      boolean logRetryCache) throws IOException {
+      boolean logRetryCache, INodesInPath iip) throws IOException {

Review comment:
       please update the javadoc for this new parameter

##########
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:
       I doubt this'll work without lock.




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Issue Time Tracking
-------------------

    Worklog Id:     (was: 723426)
    Time Spent: 40m  (was: 0.5h)

> Lock optimization for large deleteing, no locks on the collection block
> -----------------------------------------------------------------------
>
>                 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: 40m
>  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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