HDFS-6923. Propagate LazyPersist flag to DNs via DataTransferProtocol. (Arpit Agarwal)

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs/CHANGES-HDFS-6581.txt
	hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSOutputStream.java
	hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/datatransfer/Receiver.java

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

@@ -360,6 +360,7 @@ public class DFSOutputStream extends FSOutputSummer
     private long restartDeadline = 0; // Deadline of DN restart
     private BlockConstructionStage stage;  // block construction stage
     private long bytesSent = 0; // number of bytes that've been sent
+    private final boolean isLazyPersistFile;
 
     /** Nodes have been used in the pipeline before and have failed. */
     private final List<DatanodeInfo> failed = new ArrayList<DatanodeInfo>();
@@ -377,14 +378,15 @@ public class DFSOutputStream extends FSOutputSummer
      * Default construction for file create
      */
     private DataStreamer() {
-      this(null);
+      this(null, null);
     }
 
     /**
      * construction with tracing info
      */
-    private DataStreamer(Span span) {
+    private DataStreamer(HdfsFileStatus stat, Span span) {
       isAppend = false;
+      isLazyPersistFile = stat.isLazyPersist();
       stage = BlockConstructionStage.PIPELINE_SETUP_CREATE;
       traceSpan = span;
     }
@@ -404,6 +406,7 @@ public class DFSOutputStream extends FSOutputSummer
       block = lastBlock.getBlock();
       bytesSent = block.getNumBytes();
       accessToken = lastBlock.getBlockToken();
+      isLazyPersistFile = stat.isLazyPersist();
       long usedInLastBlock = stat.getLen() % blockSize;
       int freeInLastBlock = (int)(blockSize - usedInLastBlock);
 
@@ -1396,7 +1399,7 @@ public class DFSOutputStream extends FSOutputSummer
           new Sender(out).writeBlock(blockCopy, nodeStorageTypes[0], accessToken,
               dfsClient.clientName, nodes, nodeStorageTypes, null, bcs, 
               nodes.length, block.getNumBytes(), bytesSent, newGS, checksum,
-              cachingStrategy.get());
+              cachingStrategy.get(), isLazyPersistFile);
   
           // receive ack for connect
           BlockOpResponseProto resp = BlockOpResponseProto.parseFrom(
@@ -1649,7 +1652,7 @@ public class DFSOutputStream extends FSOutputSummer
     if (Trace.isTracing()) {
       traceSpan = Trace.startSpan(this.getClass().getSimpleName()).detach();
     }
-    streamer = new DataStreamer(traceSpan);
+    streamer = new DataStreamer(stat, traceSpan);
     if (favoredNodes != null && favoredNodes.length != 0) {
       streamer.setFavoredNodes(favoredNodes);
     }
@@ -1726,7 +1729,7 @@ public class DFSOutputStream extends FSOutputSummer
     } else {
       computePacketChunkSize(dfsClient.getConf().writePacketSize,
           checksum.getBytesPerChecksum());
-      streamer = new DataStreamer(traceSpan);
+      streamer = new DataStreamer(stat, traceSpan);
     }
     this.fileEncryptionInfo = stat.getFileEncryptionInfo();
   }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/datatransfer/DataTransferProtocol.java

@@ -106,8 +106,8 @@ public interface DataTransferProtocol {
       final long maxBytesRcvd,
       final long latestGenerationStamp,
       final DataChecksum requestedChecksum,
-      final CachingStrategy cachingStrategy) throws IOException;
-
+      final CachingStrategy cachingStrategy,
+      final boolean allowLazyPersist) throws IOException;
   /**
    * Transfer a block to another datanode.
    * The block stage must be

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/datatransfer/Receiver.java

@@ -148,7 +148,8 @@ public abstract class Receiver implements DataTransferProtocol {
           fromProto(proto.getRequestedChecksum()),
           (proto.hasCachingStrategy() ?
               getCachingStrategy(proto.getCachingStrategy()) :
-            CachingStrategy.newDefaultStrategy()));
+            CachingStrategy.newDefaultStrategy()),
+            (proto.hasAllowLazyPersist() ? proto.getAllowLazyPersist() : false));
      } finally {
       if (traceScope != null) traceScope.close();
      }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/datatransfer/Sender.java

@@ -128,7 +128,8 @@ public class Sender implements DataTransferProtocol {
       final long maxBytesRcvd,
       final long latestGenerationStamp,
       DataChecksum requestedChecksum,
-      final CachingStrategy cachingStrategy) throws IOException {
+      final CachingStrategy cachingStrategy,
+      final boolean allowLazyPersist) throws IOException {
     ClientOperationHeaderProto header = DataTransferProtoUtil.buildClientHeader(
         blk, clientName, blockToken);
     
@@ -146,7 +147,8 @@ public class Sender implements DataTransferProtocol {
       .setMaxBytesRcvd(maxBytesRcvd)
       .setLatestGenerationStamp(latestGenerationStamp)
       .setRequestedChecksum(checksumProto)
-      .setCachingStrategy(getCachingStrategy(cachingStrategy));
+      .setCachingStrategy(getCachingStrategy(cachingStrategy))
+      .setAllowLazyPersist(allowLazyPersist);
     
     if (source != null) {
       proto.setSource(PBHelper.convertDatanodeInfo(source));

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java

@@ -2010,7 +2010,8 @@ public class DataNode extends ReconfigurableBase
 
         new Sender(out).writeBlock(b, targetStorageTypes[0], accessToken,
             clientname, targets, targetStorageTypes, srcNode,
-            stage, 0, 0, 0, 0, blockSender.getChecksum(), cachingStrategy);
+            stage, 0, 0, 0, 0, blockSender.getChecksum(), cachingStrategy,
+            false);
 
         // send data & checksum
         blockSender.sendBlock(out, unbufOut, null);

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataXceiver.java

@@ -544,7 +544,8 @@ class DataXceiver extends Receiver implements Runnable {
       final long maxBytesRcvd,
       final long latestGenerationStamp,
       DataChecksum requestedChecksum,
-      CachingStrategy cachingStrategy) throws IOException {
+      CachingStrategy cachingStrategy,
+      final boolean allowLazyPersist) throws IOException {
     previousOpClientName = clientname;
     updateCurrentThreadName("Receiving block " + block);
     final boolean isDatanode = clientname.length() == 0;
@@ -648,10 +649,11 @@ class DataXceiver extends Receiver implements Runnable {
               HdfsConstants.SMALL_BUFFER_SIZE));
           mirrorIn = new DataInputStream(unbufMirrorIn);
 
+          // Do not propagate allowLazyPersist to downstream DataNodes.
           new Sender(mirrorOut).writeBlock(originalBlock, targetStorageTypes[0],
               blockToken, clientname, targets, targetStorageTypes, srcDataNode,
               stage, pipelineSize, minBytesRcvd, maxBytesRcvd,
-              latestGenerationStamp, requestedChecksum, cachingStrategy);
+              latestGenerationStamp, requestedChecksum, cachingStrategy, false);
 
           mirrorOut.flush();
 

hadoop-hdfs-project/hadoop-hdfs/src/main/proto/datatransfer.proto

@@ -115,6 +115,13 @@ message OpWriteBlockProto {
   optional CachingStrategyProto cachingStrategy = 10;
   optional StorageTypeProto storageType = 11 [default = DISK];
   repeated StorageTypeProto targetStorageTypes = 12;
+
+  /**
+   * Hint to the DataNode that the block can be allocated on transient
+   * storage i.e. memory and written to disk lazily. The DataNode is free
+   * to ignore this hint.
+   */
+  optional bool allowLazyPersist = 13 [default = false];
 }
   
 message OpTransferBlockProto {

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

@@ -530,6 +530,6 @@ public class TestDataTransferProtocol {
         BlockTokenSecretManager.DUMMY_TOKEN, "cl",
         new DatanodeInfo[1], new StorageType[1], null, stage,
         0, block.getNumBytes(), block.getNumBytes(), newGS,
-        checksum, CachingStrategy.newDefaultStrategy());
+        checksum, CachingStrategy.newDefaultStrategy(), false);
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDiskError.java

@@ -152,7 +152,7 @@ public class TestDiskError {
         BlockTokenSecretManager.DUMMY_TOKEN, "",
         new DatanodeInfo[0], new StorageType[0], null,
         BlockConstructionStage.PIPELINE_SETUP_CREATE, 1, 0L, 0L, 0L,
-        checksum, CachingStrategy.newDefaultStrategy());
+        checksum, CachingStrategy.newDefaultStrategy(), false);
     out.flush();
 
     // close the connection before sending the content of the block