HDFS-9600. do not check replication if the block is under construction (Contributed by Phil Yang)

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

@@ -3724,6 +3724,9 @@ Release 2.6.4 - UNRELEASED
 
   BUG FIXES
 
+    HDFS-9600. do not check replication if the block is under construction
+    (Phil Yang via vinayakumarb)
+
 Release 2.6.3 - 2015-12-17
 
   INCOMPATIBLE CHANGES

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

@@ -3946,7 +3946,8 @@ public class BlockManager implements BlockStatsMXBean {
    */
   boolean isNeededReplication(BlockInfo storedBlock, int current) {
     int expected = getExpectedReplicaNum(storedBlock);
-    return current < expected || !isPlacementPolicySatisfied(storedBlock);
+    return storedBlock.isComplete()
+        && (current < expected || !isPlacementPolicySatisfied(storedBlock));
   }
 
   public short getExpectedReplicaNum(BlockInfo block) {

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

@@ -243,8 +243,9 @@ public class DecommissionManager {
       NumberReplicas numberReplicas) {
     final int numExpected = blockManager.getExpectedReplicaNum(block);
     final int numLive = numberReplicas.liveReplicas();
-    if (!blockManager.isNeededReplication(block, numLive)) {
-      // Block doesn't need replication. Skip.
+    if (numLive >= numExpected
+        && blockManager.isPlacementPolicySatisfied(block)) {
+      // Block has enough replica, skip
       LOG.trace("Block {} does not need replication.", block);
       return true;
     }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockManager.java

@@ -32,6 +32,7 @@ import static org.mockito.Mockito.verify;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.EnumSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map.Entry;
@@ -48,16 +49,22 @@ import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.CreateFlag;
+import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.StorageType;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.DFSOutputStream;
 import org.apache.hadoop.hdfs.DFSTestUtil;
+import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.BlockListAsLongs;
+import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
+import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor.BlockTargetPair;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
 import org.apache.hadoop.hdfs.server.datanode.DataNodeTestUtils;
@@ -70,8 +77,11 @@ import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
 import org.apache.hadoop.hdfs.server.namenode.TestINodeFile;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeRegistration;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeStorage;
+import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocols;
 import org.apache.hadoop.hdfs.server.protocol.ReceivedDeletedBlockInfo;
 import org.apache.hadoop.hdfs.server.protocol.StorageReceivedDeletedBlocks;
+import org.apache.hadoop.io.EnumSetWritable;
+import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.ipc.RemoteException;
 import org.apache.hadoop.metrics2.MetricsRecordBuilder;
 import org.apache.hadoop.net.NetworkTopology;
@@ -397,6 +407,54 @@ public class TestBlockManager {
     assertFalse(bm.isNeededReplication(block, bm.countLiveNodes(block)));
   }
   
+  @Test(timeout = 60000)
+  public void testNeededReplicationWhileAppending() throws IOException {
+    Configuration conf = new HdfsConfiguration();
+    String src = "/test-file";
+    Path file = new Path(src);
+    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).build();
+    cluster.waitActive();
+    try {
+      BlockManager bm = cluster.getNamesystem().getBlockManager();
+      FileSystem fs = cluster.getFileSystem();
+      NamenodeProtocols namenode = cluster.getNameNodeRpc();
+      DFSOutputStream out = null;
+      try {
+        out = (DFSOutputStream) (fs.create(file).
+            getWrappedStream());
+        out.write(1);
+        out.hflush();
+        out.close();
+        FSDataInputStream in = null;
+        ExtendedBlock oldBlock = null;
+        try {
+          in = fs.open(file);
+          oldBlock = DFSTestUtil.getAllBlocks(in).get(0).getBlock();
+        } finally {
+          IOUtils.closeStream(in);
+        }
+
+        String clientName =
+            ((DistributedFileSystem) fs).getClient().getClientName();
+        namenode.append(src, clientName, new EnumSetWritable<>(
+            EnumSet.of(CreateFlag.APPEND)));
+        LocatedBlock newLocatedBlock =
+            namenode.updateBlockForPipeline(oldBlock, clientName);
+        ExtendedBlock newBlock =
+            new ExtendedBlock(oldBlock.getBlockPoolId(), oldBlock.getBlockId(),
+                oldBlock.getNumBytes(),
+                newLocatedBlock.getBlock().getGenerationStamp());
+        namenode.updatePipeline(clientName, oldBlock, newBlock,
+            newLocatedBlock.getLocations(), newLocatedBlock.getStorageIDs());
+        BlockInfo bi = bm.getStoredBlock(newBlock.getLocalBlock());
+        assertFalse(bm.isNeededReplication(bi, bm.countLiveNodes(bi)));
+      } finally {
+        IOUtils.closeStream(out);
+      }
+    } finally {
+      cluster.shutdown();
+    }
+  }
   
   /**
    * Tell the block manager that replication is completed for the given