From 99f6e064d4d080ea220c7934ce190d87573576c0 Mon Sep 17 00:00:00 2001
From: hunshenshi <289517357@qq.com>
Date: Tue, 12 Mar 2019 17:28:28 +0800
Subject: [PATCH] HDFS-14361:SNN will always upload fsimage

---
 .../hadoop/hdfs/server/namenode/ha/StandbyCheckpointer.java   | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyCheckpointer.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyCheckpointer.java
index 6f8ce91ee4c19..6f61e14de7135 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyCheckpointer.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyCheckpointer.java
@@ -165,6 +165,8 @@ private void doCheckpoint(boolean sendCheckpoint) throws InterruptedException, I
     // Acquire cpLock to make sure no one is modifying the name system.
     // It does not need the full namesystem write lock, since the only thing
     // that modifies namesystem on standby node is edit log replaying.
+    // checkpoint是namespace的一个快照，所以在dump快照的时候需要锁，避免修改namespace的内容，
+    // 这也是checkpoint要在snn上执行的一个原因
     namesystem.cpLockInterruptibly();
     try {
       assert namesystem.getEditLog().isOpenForRead() :
@@ -265,8 +267,8 @@ public TransferFsImage.TransferResult call()
       //Update only when response from remote about success or
       lastUploadTime = monotonicNow();
       // we are primary if we successfully updated the ANN
-      this.isPrimaryCheckPointer = success;
     }
+    this.isPrimaryCheckPointer = success;
     // cleaner than copying code for multiple catch statements and better than catching all
     // exceptions, so we just handle the ones we expect.
     if (ie != null || ioe != null) {