From b0bfd09c41a1afa2e019f8a2482f1689a348bbde Mon Sep 17 00:00:00 2001
From: ZanderXu <xuzengqiang5127@gmail.com>
Date: Sun, 9 Oct 2022 18:58:09 +0800
Subject: [PATCH] HDFS-16798. HDFS-16798. SerialNumberMap should decrease
 current counter if the item exist. (#4987). Contributed by ZanderXu.

Signed-off-by: He Xiaoqiao <hexiaoqiao@apache.org>
---
 .../org/apache/hadoop/hdfs/server/namenode/SerialNumberMap.java  | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberMap.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberMap.java
index d9a41428b5..ff116b5118 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberMap.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberMap.java
@@ -68,6 +68,7 @@ public int get(T t) {
       }
       Integer old = t2i.putIfAbsent(t, sn);
       if (old != null) {
+        current.getAndDecrement();
         return old;
       }
       i2t.put(sn, t);