From 95a70c0fdfb2a2534a54d01012c49d4ff23117f6 Mon Sep 17 00:00:00 2001
From: Kihwal Lee <kihwal@apache.org>
Date: Fri, 16 Jul 2021 14:23:36 -0500
Subject: [PATCH] HDFS-16127. Improper pipeline close recovery causes a
 permanent write failure or data loss. Contributed by Kihwal Lee.

(cherry picked from commit 47002719f2aa4ff58378d528d38b0f0962a45c25)
---
 .../java/org/apache/hadoop/hdfs/DataStreamer.java  | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DataStreamer.java b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DataStreamer.java
index 110261b0d6b..e1d104e6529 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DataStreamer.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DataStreamer.java
@@ -778,7 +778,19 @@ public void run() {
         // Is this block full?
         if (one.isLastPacketInBlock()) {
           // wait for the close packet has been acked
-          waitForAllAcks();
+          try {
+            waitForAllAcks();
+          } catch (IOException ioe) {
+            // No need to do a close recovery if the last packet was acked.
+            // i.e. ackQueue is empty.  waitForAllAcks() can get an exception
+            // (e.g. connection reset) while sending a heartbeat packet,
+            // if the DN sends the final ack and closes the connection.
+            synchronized (dataQueue) {
+              if (!ackQueue.isEmpty()) {
+                throw ioe;
+              }
+            }
+          }
           if (shouldStop()) {
             continue;
           }