From 7354547a02998de0b8d79954421e3689c4e5accf Mon Sep 17 00:00:00 2001
From: Andrew Wang <wang@apache.org>
Date: Fri, 10 Jan 2014 20:10:44 +0000
Subject: [PATCH] HDFS-5756. hadoopRzOptionsSetByteBufferPool does not accept
 NULL argument, contrary to docs. Contributed by Colin Patrick McCabe.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1557244 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt   |  3 +++
 .../src/main/native/libhdfs/hdfs.c            | 20 ++++++++++---------
 .../libhdfs/test/test_libhdfs_zerocopy.c      |  6 ++++++
 3 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 0440ff73b2c..d1fd8ba7c9a 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -741,6 +741,9 @@ Release 2.4.0 - UNRELEASED
 
     HDFS-5449. WebHdfs compatibility broken between 2.2 and 1.x / 23.x (kihwal)
 
+    HDFS-5756. hadoopRzOptionsSetByteBufferPool does not accept NULL argument,
+    contrary to docs. (cmccabe via wang)
+
   BREAKDOWN OF HDFS-2832 SUBTASKS AND RELATED JIRAS
 
     HDFS-4985. Add storage type to the protocol and expose it in block report
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/hdfs.c b/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/hdfs.c
index bd1ae5d40ba..07088d09c41 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/hdfs.c
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/hdfs.c
@@ -2174,16 +2174,18 @@ int hadoopRzOptionsSetByteBufferPool(
         return -1;
     }
 
-    // Note: we don't have to call hadoopRzOptionsClearCached in this
-    // function, since the ByteBufferPool is passed separately from the
-    // EnumSet of ReadOptions.
+    if (className) {
+      // Note: we don't have to call hadoopRzOptionsClearCached in this
+      // function, since the ByteBufferPool is passed separately from the
+      // EnumSet of ReadOptions.
 
-    jthr = constructNewObjectOfClass(env, &byteBufferPool, className, "()V");
-    if (jthr) {
-        printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
-            "hadoopRzOptionsSetByteBufferPool(className=%s): ", className);
-        errno = EINVAL;
-        return -1;
+      jthr = constructNewObjectOfClass(env, &byteBufferPool, className, "()V");
+      if (jthr) {
+          printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
+              "hadoopRzOptionsSetByteBufferPool(className=%s): ", className);
+          errno = EINVAL;
+          return -1;
+      }
     }
     if (opts->byteBufferPool) {
         // Delete any previous ByteBufferPool we had.
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/test/test_libhdfs_zerocopy.c b/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/test/test_libhdfs_zerocopy.c
index b22fee12964..ba6ac0904bf 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/test/test_libhdfs_zerocopy.c
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/test/test_libhdfs_zerocopy.c
@@ -140,6 +140,12 @@ static int doTestZeroCopyReads(hdfsFS fs, const char *fileName)
     EXPECT_NULL(hadoopReadZero(file, opts, TEST_ZEROCOPY_FULL_BLOCK_SIZE));
     EXPECT_INT_EQ(EPROTONOSUPPORT, errno);
 
+    /* Verify that setting a NULL ByteBufferPool class works. */
+    EXPECT_ZERO(hadoopRzOptionsSetByteBufferPool(opts, NULL));
+    EXPECT_ZERO(hadoopRzOptionsSetSkipChecksum(opts, 0));
+    EXPECT_NULL(hadoopReadZero(file, opts, TEST_ZEROCOPY_FULL_BLOCK_SIZE));
+    EXPECT_INT_EQ(EPROTONOSUPPORT, errno);
+
     /* Now set a ByteBufferPool and try again.  It should succeed this time. */
     EXPECT_ZERO(hadoopRzOptionsSetByteBufferPool(opts,
           ELASTIC_BYTE_BUFFER_POOL_CLASS));