From 6151c2bea7bcd9e458b09a5bf5b1798ed6c0def9 Mon Sep 17 00:00:00 2001
From: Andrew Wang <wang@apache.org>
Date: Thu, 11 Sep 2014 10:59:09 -0700
Subject: [PATCH] HDFS-7045. Fix NameNode deadlock when opening file under
 /.reserved path. Contributed by Yi Liu.

(cherry picked from commit 1e684995d7ac20d1c27ca1c1bef37dd2ee00e630)
---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt   |  3 +++
 .../hdfs/server/namenode/FSNamesystem.java    |  2 +-
 .../java/org/apache/hadoop/hdfs/TestRead.java | 22 +++++++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 3b3a723e01d..6c8282c5926 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -383,6 +383,9 @@ Release 2.6.0 - UNRELEASED
     HDFS-6621. Hadoop Balancer prematurely exits iterations.
     (Rafal Wojdyla and Benjamin Bowman via wang)
 
+    HDFS-7045. Fix NameNode deadlock when opening file under /.reserved path.
+    (Yi Liu via wang)
+
     BREAKDOWN OF HDFS-6134 AND HADOOP-10150 SUBTASKS AND RELATED JIRAS
   
       HDFS-6387. HDFS CLI admin tool for creating & deleting an
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
index fa77526a50b..5b0c3f761cb 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
@@ -1824,8 +1824,8 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
         checkOperation(OperationCategory.WRITE);
         writeLock(); // writelock is needed to set accesstime
       }
-      src = resolvePath(src, pathComponents);
       try {
+        src = resolvePath(src, pathComponents);
         if (isReadOp) {
           checkOperation(OperationCategory.READ);
         } else {
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestRead.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestRead.java
index c8d50297b3d..378d8bba153 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestRead.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestRead.java
@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.hdfs;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 
@@ -80,4 +81,25 @@ public class TestRead {
     testEOF(cluster, 10000);   
     cluster.shutdown();
   }
+
+  /**
+   * Regression test for HDFS-7045.
+   * If deadlock happen, the test will time out.
+   * @throws Exception
+   */
+  @Test(timeout=60000)
+  public void testReadReservedPath() throws Exception {
+    Configuration conf = new Configuration();
+    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).
+        numDataNodes(1).format(true).build();
+    try {
+      FileSystem fs = cluster.getFileSystem();
+      fs.open(new Path("/.reserved/.inodes/file"));
+      Assert.fail("Open a non existing file should fail.");
+    } catch (FileNotFoundException e) {
+      // Expected
+    } finally {
+      cluster.shutdown();
+    }
+  }
 }