HDFS-6288. DFSInputStream Pread doesn't update ReadStatistics. Contributed by Juan Yu.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1590778 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -160,6 +160,9 @@ Release 2.5.0 - UNRELEASED
     HDFS-6218. Audit log should use true client IP for proxied webhdfs
     operations. (daryn via kihwal)
 
+    HDFS-6288. DFSInputStream Pread doesn't update ReadStatistics.
+    (Juan Yu via wang)
+
 Release 2.4.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java

@@ -1038,6 +1038,8 @@ implements ByteBufferReadable, CanSetDropBehind, CanSetReadahead,
             setConfiguration(dfsClient.getConfiguration()).
             build();
         int nread = reader.readAll(buf, offset, len);
+        updateReadStatistics(readStatistics, nread, reader);
+
         if (nread != len) {
           throw new IOException("truncated return from reader.read(): " +
                                 "excpected " + len + ", got " + nread);

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

@@ -94,11 +94,25 @@ public class TestPread {
   private void doPread(FSDataInputStream stm, long position, byte[] buffer,
                        int offset, int length) throws IOException {
     int nread = 0;
+    long totalRead = 0;
+    DFSInputStream dfstm = null;
+
+    if (stm.getWrappedStream() instanceof DFSInputStream) {
+      dfstm = (DFSInputStream) (stm.getWrappedStream());
+      totalRead = dfstm.getReadStatistics().getTotalBytesRead();
+    }
+
     while (nread < length) {
-      int nbytes = stm.read(position+nread, buffer, offset+nread, length-nread);
+      int nbytes =
+          stm.read(position + nread, buffer, offset + nread, length - nread);
       assertTrue("Error in pread", nbytes > 0);
       nread += nbytes;
     }
+
+    if (dfstm != null) {
+      assertEquals("Expected read statistic to be incremented", length, dfstm
+          .getReadStatistics().getTotalBytesRead() - totalRead);
+    }
   }
   
   private void pReadFile(FileSystem fileSys, Path name) throws IOException {