HDFS-14308. DFSStripedInputStream curStripeBuf is not freed by unbuffer() (#1667)

Reviewed-by: Aravindan Vijayan <avijayan@cloudera.com>
Reviewed-by: Wei-Chiu Chuang <weichiu@apache.org>
(cherry picked from commit 30db895b59d250788d029cb2013bb4712ef9b546)

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSStripedInputStream.java

@@ -70,7 +70,8 @@ public class DFSStripedInputStream extends DFSInputStream {
   private final int groupSize;
   /** the buffer for a complete stripe. */
   private ByteBuffer curStripeBuf;
-  private ByteBuffer parityBuf;
+  @VisibleForTesting
+  protected ByteBuffer parityBuf;
   private final ErasureCodingPolicy ecPolicy;
   private RawErasureDecoder decoder;
 
@@ -129,7 +130,7 @@ public class DFSStripedInputStream extends DFSInputStream {
     curStripeRange = new StripeRange(0, 0);
   }
 
-  protected ByteBuffer getParityBuffer() {
+  protected synchronized ByteBuffer getParityBuffer() {
     if (parityBuf == null) {
       parityBuf = BUFFER_POOL.getBuffer(useDirectBuffer(),
           cellSize * parityBlkNum);
@@ -554,4 +555,17 @@ public class DFSStripedInputStream extends DFSInputStream {
     throw new UnsupportedOperationException(
         "Not support enhanced byte buffer access.");
   }
+
+  @Override
+  public synchronized void unbuffer() {
+    super.unbuffer();
+    if (curStripeBuf != null) {
+      BUFFER_POOL.putBuffer(curStripeBuf);
+      curStripeBuf = null;
+    }
+    if (parityBuf != null) {
+      BUFFER_POOL.putBuffer(parityBuf);
+      parityBuf = null;
+    }
+  }
 }

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

@@ -627,4 +627,41 @@ public class TestDFSStripedInputStream {
       }
     }
   }
+
+  @Test
+  public void testUnbuffer() throws Exception {
+    final int numBlocks = 2;
+    final int fileSize = numBlocks * blockGroupSize;
+    DFSTestUtil.createStripedFile(cluster, filePath, null, numBlocks,
+        stripesPerBlock, false, ecPolicy);
+    LocatedBlocks lbs = fs.getClient().namenode.
+        getBlockLocations(filePath.toString(), 0, fileSize);
+
+    for (LocatedBlock lb : lbs.getLocatedBlocks()) {
+      assert lb instanceof LocatedStripedBlock;
+      LocatedStripedBlock bg = (LocatedStripedBlock)(lb);
+      for (int i = 0; i < dataBlocks; i++) {
+        Block blk = new Block(bg.getBlock().getBlockId() + i,
+            stripesPerBlock * cellSize,
+            bg.getBlock().getGenerationStamp());
+        blk.setGenerationStamp(bg.getBlock().getGenerationStamp());
+        cluster.injectBlocks(i, Arrays.asList(blk),
+            bg.getBlock().getBlockPoolId());
+      }
+    }
+      DFSStripedInputStream in = new DFSStripedInputStream(fs.getClient(),
+          filePath.toString(), false, ecPolicy, null);
+      ByteBuffer readBuffer = ByteBuffer.allocate(fileSize);
+      int done = 0;
+      while (done < fileSize) {
+        int ret = in.read(readBuffer);
+        assertTrue(ret > 0);
+        done += ret;
+      }
+      in.unbuffer();
+      ByteBuffer curStripeBuf = (in.getCurStripeBuf());
+      assertNull(curStripeBuf);
+      assertNull(in.parityBuf);
+      in.close();
+  }
 }