HDFS-14754. Erasure Coding : The number of Under-Replicated Blocks never reduced. Contributed by hemanthboyina.

(cherry picked from commit 4852a90e4b)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java

@@ -3440,8 +3440,7 @@ public class BlockManager implements BlockStatsMXBean {
   private boolean shouldProcessExtraRedundancy(NumberReplicas num,
       int expectedNum) {
     final int numCurrent = num.liveReplicas();
-    return numCurrent > expectedNum ||
-        (numCurrent == expectedNum && num.redundantInternalBlocks() > 0);
+    return numCurrent > expectedNum || num.redundantInternalBlocks() > 0;
   }
 
   /**

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestRedudantBlocks.java

@@ -0,0 +1,137 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.HashSet;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.DFSTestUtil;
+import org.apache.hadoop.hdfs.DistributedFileSystem;
+import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.apache.hadoop.hdfs.protocol.Block;
+import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
+import org.apache.hadoop.hdfs.protocol.LocatedBlock;
+import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
+import org.apache.hadoop.hdfs.protocol.LocatedStripedBlock;
+import org.apache.hadoop.hdfs.protocol.SystemErasureCodingPolicies;
+import org.apache.hadoop.hdfs.server.datanode.SimulatedFSDataset;
+import org.apache.hadoop.hdfs.util.StripedBlockUtil;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Test RedudantBlocks.
+ */
+public class TestRedudantBlocks {
+
+  private MiniDFSCluster cluster;
+  private DistributedFileSystem fs;
+  private final Path dirPath = new Path("/striped");
+  private Path filePath = new Path(dirPath, "file");
+  private final ErasureCodingPolicy ecPolicy =
+      SystemErasureCodingPolicies.getPolicies().get(1);
+  private final short dataBlocks = (short) ecPolicy.getNumDataUnits();
+  private final short parityBlocks = (short) ecPolicy.getNumParityUnits();
+  private final short groupSize = (short) (dataBlocks + parityBlocks);
+  private final int cellSize = ecPolicy.getCellSize();
+  private final int stripesPerBlock = 4;
+  private final int blockSize = stripesPerBlock * cellSize;
+  private final int numDNs = groupSize + 1;
+
+  @Before
+  public void setup() throws IOException {
+    Configuration conf = new Configuration();
+    conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, blockSize);
+    // disable block recovery
+    conf.setInt(DFSConfigKeys.DFS_NAMENODE_REDUNDANCY_INTERVAL_SECONDS_KEY, 1);
+    conf.setInt(DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_KEY, 1);
+    SimulatedFSDataset.setFactory(conf);
+    cluster = new MiniDFSCluster.Builder(conf).numDataNodes(numDNs).build();
+    cluster.waitActive();
+    fs = cluster.getFileSystem();
+    fs.enableErasureCodingPolicy(ecPolicy.getName());
+    fs.mkdirs(dirPath);
+    fs.getClient().setErasureCodingPolicy(dirPath.toString(),
+        ecPolicy.getName());
+  }
+
+  @After
+  public void tearDown() {
+    if (cluster != null) {
+      cluster.shutdown();
+      cluster = null;
+    }
+  }
+
+  @Test
+  public void testProcessOverReplicatedAndRedudantBlock() throws Exception {
+    long fileLen = dataBlocks * blockSize;
+    DFSTestUtil.createStripedFile(cluster, filePath, null, 1, stripesPerBlock,
+        false);
+    LocatedBlocks lbs = cluster.getNameNodeRpc()
+        .getBlockLocations(filePath.toString(), 0, fileLen);
+    LocatedStripedBlock bg = (LocatedStripedBlock) (lbs.get(0));
+    long gs = bg.getBlock().getGenerationStamp();
+    String bpid = bg.getBlock().getBlockPoolId();
+    long groupId = bg.getBlock().getBlockId();
+    Block blk = new Block(groupId, blockSize, gs);
+    int i = 0;
+    // one missing block
+    for (; i < groupSize - 1; i++) {
+      blk.setBlockId(groupId + i);
+      cluster.injectBlocks(i, Arrays.asList(blk), bpid);
+    }
+    cluster.triggerBlockReports();
+    // one redundant block
+    blk.setBlockId(groupId + 2);
+    cluster.injectBlocks(i, Arrays.asList(blk), bpid);
+
+    // update blocksMap
+    cluster.triggerBlockReports();
+    // add to invalidates
+    cluster.triggerHeartbeats();
+    // datanode delete block
+    cluster.triggerHeartbeats();
+    // update blocksMap
+    cluster.triggerBlockReports();
+
+    HashSet<Long> blockIdsSet = new HashSet<Long>();
+
+    lbs = cluster.getNameNodeRpc().getBlockLocations(filePath.toString(), 0,
+        fileLen);
+    bg = (LocatedStripedBlock) (lbs.get(0));
+
+    final LocatedBlock[] blocks = StripedBlockUtil.parseStripedBlockGroup(bg,
+        cellSize, dataBlocks, parityBlocks);
+
+    for (LocatedBlock dn : blocks) {
+      if (dn != null) {
+        blockIdsSet.add(dn.getBlock().getBlockId());
+      }
+    }
+    assertEquals(groupSize, blockIdsSet.size());
+
+  }
+}