From fe069fcf71cb437c00520fe384214d831e1184d7 Mon Sep 17 00:00:00 2001
From: zeekling <lingzhaohui@zeekling.cn>
Date: Sat, 13 Apr 2024 22:08:29 +0800
Subject: [PATCH] =?UTF-8?q?FSDirectory=E8=AF=A6=E8=A7=A3:=E9=85=8D?=
 =?UTF-8?q?=E7=BD=AE=E5=92=8C=E5=8F=98=E9=87=8F?=
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---
 hdfs/FSDirectory详解.md | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/hdfs/FSDirectory详解.md b/hdfs/FSDirectory详解.md
index 6627c62..f931704 100644
--- a/hdfs/FSDirectory详解.md
+++ b/hdfs/FSDirectory详解.md
@@ -74,4 +74,25 @@ boolean delete(String src, boolean recursive, boolean logRetryCache) throws IOEx
 
 **FSDirDeleteOp.delete 实现逻辑**
 
+- 检查权限：调用FSDirectory的函数checkPermission检查权限。
+- 如果是非空的文件夹，检查是否有-r参数。如果没有-r参数则需要报错。
+- 调用deleteInternal，开始删除文件夹。核心删除代码如下：
+
+```java
+List<INodeDirectory> snapshottableDirs = new ArrayList<>();
+FSDirSnapshotOp.checkSnapshot(fsd, iip, snapshottableDirs);
+ReclaimContext context = new ReclaimContext(
+    fsd.getBlockStoragePolicySuite(), collectedBlocks, removedINodes,
+    removedUCFiles);
+// 更核心的删除代码再这个函数里面，会调用destroyAndCollectBlocks删除block,代码：targetNode.destroyAndCollectBlocks(reclaimContext);
+if (unprotectedDelete(fsd, iip, context, mtime)) {
+  filesRemoved = context.quotaDelta().getNsDelta();
+  fsn.removeSnapshottableDirs(snapshottableDirs);
+}
+fsd.updateReplicationFactor(context.collectedBlocks()
+                                .toUpdateReplicationInfo());
+fsd.updateCount(iip, context.quotaDelta(), false);
+```
+- 删除EditLog。
+- 调用incrDeletedFileCount更新metrics信息。