HDFS-7315. DFSTestUtil.readFileBuffer opens extra FSDataInputStream. Contributed by Plamen Jeliazkov.

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -375,6 +375,9 @@ Release 2.7.0 - UNRELEASED
     HDFS-7263. Snapshot read can reveal future bytes for appended files.
     (Tao Luo via shv)
 
+    HDFS-7315. DFSTestUtil.readFileBuffer opens extra FSDataInputStream.
+    (Plamen Jeliazkov via wheat9)
+
 Release 2.6.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/DFSTestUtil.java

@@ -267,7 +267,7 @@ public class DFSTestUtil {
     try {
       FSDataInputStream in = fs.open(fileName);
       try {
-        IOUtils.copyBytes(fs.open(fileName), os, 1024, true);
+        IOUtils.copyBytes(in, os, 1024, true);
         return os.toByteArray();
       } finally {
         in.close();