From 22ed1471bd5ef5988432fb4ae8034f4f90185405 Mon Sep 17 00:00:00 2001
From: yliu <yliu@apache.org>
Date: Thu, 8 Oct 2015 10:26:30 +0800
Subject: [PATCH] HDFS-9137. DeadLock between DataNode#refreshVolumes and
 BPOfferService#registrationSucceeded. (Uma Maheswara Rao G via yliu)

---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt   |  3 +++
 .../hadoop/hdfs/server/datanode/DataNode.java | 25 ++++++++++++++-----
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 9250c2b0036..756052c190f 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -1169,6 +1169,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-9211. Fix incorrect version in hadoop-hdfs-native-client/pom.xml
     from HDFS-9170 branch-2 backport. (Eric Payne via wang)
 
+    HDFS-9137. DeadLock between DataNode#refreshVolumes and
+    BPOfferService#registrationSucceeded. (Uma Maheswara Rao G via yliu)
+
 Release 2.7.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
index d1e0160d03d..b9be20e2770 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
@@ -502,12 +502,29 @@ public class DataNode extends ReconfigurableBase
   public void reconfigurePropertyImpl(String property, String newVal)
       throws ReconfigurationException {
     if (property.equals(DFS_DATANODE_DATA_DIR_KEY)) {
+      IOException rootException = null;
       try {
         LOG.info("Reconfiguring " + property + " to " + newVal);
         this.refreshVolumes(newVal);
       } catch (IOException e) {
-        throw new ReconfigurationException(property, newVal,
-            getConf().get(property), e);
+        rootException = e;
+      } finally {
+        // Send a full block report to let NN acknowledge the volume changes.
+        try {
+          triggerBlockReport(
+              new BlockReportOptions.Factory().setIncremental(false).build());
+        } catch (IOException e) {
+          LOG.warn("Exception while sending the block report after refreshing"
+              + " volumes " + property + " to " + newVal, e);
+          if (rootException == null) {
+            rootException = e;
+          }
+        } finally {
+          if (rootException != null) {
+            throw new ReconfigurationException(property, newVal,
+                getConf().get(property), rootException);
+          }
+        }
       }
     } else {
       throw new ReconfigurationException(
@@ -689,10 +706,6 @@ public class DataNode extends ReconfigurableBase
       conf.set(DFS_DATANODE_DATA_DIR_KEY,
           Joiner.on(",").join(effectiveVolumes));
       dataDirs = getStorageLocations(conf);
-
-      // Send a full block report to let NN acknowledge the volume changes.
-      triggerBlockReport(new BlockReportOptions.Factory()
-          .setIncremental(false).build());
     }
   }