From 3da3a4a979565504ef917b1e94756117ab26d5cb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=A1=BE=E9=B9=8F?= <gupeng@gupengdeMacBook-Pro.local>
Date: Mon, 26 Aug 2024 11:43:19 +0800
Subject: [PATCH] Fix the issue of deleting empty directories failing due to
 cache eviction in CachingInodeStore.

---
 .../metastore/caching/CachingInodeStore.java  |  8 +++++--
 ...chingInodeStoreMockedBackingStoreTest.java | 24 ++++++++++++++++++-
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/core/server/master/src/main/java/alluxio/master/metastore/caching/CachingInodeStore.java b/core/server/master/src/main/java/alluxio/master/metastore/caching/CachingInodeStore.java
index 614e5683c34a..b7ed0de3534b 100644
--- a/core/server/master/src/main/java/alluxio/master/metastore/caching/CachingInodeStore.java
+++ b/core/server/master/src/main/java/alluxio/master/metastore/caching/CachingInodeStore.java
@@ -236,8 +236,7 @@ public boolean hasChildren(InodeDirectoryView inode, ReadOption option) {
     if (cached.isPresent()) {
       return !cached.get().isEmpty();
     }
-    return !mListingCache.getDataFromBackingStore(inode.getId(), option).isEmpty()
-        || mBackingStore.hasChildren(inode);
+    return !mListingCache.getDataFromBackingStore(inode.getId(), option).isEmpty();
   }
 
   @VisibleForTesting
@@ -854,6 +853,11 @@ private void evict() {
           mWeight.get(), System.currentTimeMillis() - startTime);
     }
 
+    @VisibleForTesting
+    void evictForTesting() {
+      evict();
+    }
+
     private int weight(ListingCacheEntry entry) {
       Preconditions.checkNotNull(entry);
       Preconditions.checkNotNull(entry.mChildren);
diff --git a/core/server/master/src/test/java/alluxio/master/metastore/caching/CachingInodeStoreMockedBackingStoreTest.java b/core/server/master/src/test/java/alluxio/master/metastore/caching/CachingInodeStoreMockedBackingStoreTest.java
index ab85e4fbb807..184405bb5110 100644
--- a/core/server/master/src/test/java/alluxio/master/metastore/caching/CachingInodeStoreMockedBackingStoreTest.java
+++ b/core/server/master/src/test/java/alluxio/master/metastore/caching/CachingInodeStoreMockedBackingStoreTest.java
@@ -70,7 +70,8 @@ public class CachingInodeStoreMockedBackingStoreTest {
       ImmutableMap.of(PropertyKey.MASTER_METASTORE_INODE_CACHE_MAX_SIZE, CACHE_SIZE,
           PropertyKey.MASTER_METASTORE_INODE_CACHE_EVICT_BATCH_SIZE, 5,
           PropertyKey.LEAK_DETECTOR_LEVEL, ResourceLeakDetector.Level.PARANOID,
-          PropertyKey.LEAK_DETECTOR_EXIT_ON_LEAK, true),
+          PropertyKey.LEAK_DETECTOR_EXIT_ON_LEAK, true,
+          PropertyKey.MASTER_METASTORE_INODE_CACHE_LOW_WATER_MARK_RATIO, 0),
       Configuration.modifiableGlobal());
 
   @Before
@@ -335,6 +336,27 @@ public void skipCache() throws Exception {
     assertEquals(0, mStore.mInodeCache.getCacheMap().size());
   }
 
+  @Test
+  public void evictInodeForTestHasChildren() throws Exception {
+    MutableInodeDirectory myTestdir =
+        MutableInodeDirectory.create(500, 0, "guptest", CreateDirectoryContext.defaults());
+    mStore.writeNewInode(myTestdir);
+    mStore.mListingCache.evictForTesting();
+    mStore.mEdgeCache.flush();
+    mStore.mInodeCache.flush();
+
+    long id = 6000;
+    MutableInodeFile child =
+        MutableInodeFile.create(id, 500, "child" + id, 0, CreateFileContext.defaults());
+    mStore.writeNewInode(child);
+    mStore.addChild(500, child);
+
+    mStore.mEdgeCache.flush();
+
+    mStore.removeInodeAndParentEdge(child);
+    assertEquals(false, mStore.hasChildren(myTestdir));
+  }
+
   private void verifyNoBackingStoreReads() {
     verify(mBackingStore, times(0)).getChild(anyLong(), anyString());
     verify(mBackingStore, times(0)).getChildId(anyLong(), anyString());