From ceec19e61a5eea6af749881429da1fa470d0dfc6 Mon Sep 17 00:00:00 2001
From: Kidd5368 <57645247+Kidd53685368@users.noreply.github.com>
Date: Fri, 23 Sep 2022 11:27:56 +0800
Subject: [PATCH] HDFS-16776 Erasure Coding: The length of targets should be
 checked when DN gets a reconstruction task (#4901)

(cherry picked from commit 9a29075f915173e24c77cf8aea2908da0aa328e3)
---
 .../server/datanode/erasurecode/StripedReconstructor.java     | 4 ++++
 .../hdfs/server/datanode/erasurecode/StripedWriter.java       | 4 +++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/erasurecode/StripedReconstructor.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/erasurecode/StripedReconstructor.java
index 06346c6b32..7f41dac591 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/erasurecode/StripedReconstructor.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/erasurecode/StripedReconstructor.java
@@ -277,6 +277,10 @@ RawErasureDecoder getDecoder() {
     return decoder;
   }
 
+  int getNumLiveBlocks(){
+    return liveBitSet.cardinality();
+  }
+
   void cleanup() {
     if (decoder != null) {
       decoder.release();
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/erasurecode/StripedWriter.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/erasurecode/StripedWriter.java
index 683b63fa14..4b7e1abdb1 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/erasurecode/StripedWriter.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/erasurecode/StripedWriter.java
@@ -82,8 +82,10 @@ class StripedWriter {
     assert targetStorageIds != null;
 
     writers = new StripedBlockWriter[targets.length];
-
     targetIndices = new short[targets.length];
+    Preconditions.checkArgument(
+            targetIndices.length <= dataBlkNum + parityBlkNum - reconstructor.getNumLiveBlocks(),
+            "Reconstruction work gets too much targets.");
     Preconditions.checkArgument(targetIndices.length <= parityBlkNum,
         "Too much missed striped blocks.");
     initTargetIndices();