HDFS-6086. Fix a case where zero-copy or no-checksum reads were not allowed even when the block was cached. (cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1576533 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -598,6 +598,9 @@ Release 2.4.0 - UNRELEASED
     HDFS-6077. Running slive with webhdfs on secure HA cluster fails with unkown
     host exception. (jing9)
 
+    HDFS-6086. Fix a case where zero-copy or no-checksum reads were not allowed
+    even when the block was cached (cmccabe)
+
   BREAKDOWN OF HDFS-5698 SUBTASKS AND RELATED JIRAS
 
     HDFS-5717. Save FSImage header in protobuf. (Haohui Mai via jing9)

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

@@ -191,7 +191,15 @@ public class ShortCircuitReplica {
     if (slot == null) {
       return false;
     }
-    return slot.addAnchor();
+    boolean result = slot.addAnchor();
+    if (LOG.isTraceEnabled()) {
+      if (result) {
+        LOG.trace(this + ": added no-checksum anchor to slot " + slot);
+      } else {
+        LOG.trace(this + ": could not add no-checksum anchor to slot " + slot);
+      }
+    }
+    return result;
   }
 
   /**

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

@@ -261,8 +261,10 @@ class DataXceiver extends Receiver implements Runnable {
             "anything but a UNIX domain socket.");
       }
       if (slotId != null) {
+        boolean isCached = datanode.data.
+            isCached(blk.getBlockPoolId(), blk.getBlockId());
         datanode.shortCircuitRegistry.registerSlot(
-            ExtendedBlockId.fromExtendedBlock(blk), slotId);
+            ExtendedBlockId.fromExtendedBlock(blk), slotId, isCached);
       }
       try {
         fis = datanode.requestShortCircuitFdsForRead(blk, token, maxVersion);

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

@@ -287,12 +287,12 @@ public class ShortCircuitRegistry {
     return info;
   }
   
-  public synchronized void registerSlot(ExtendedBlockId blockId, SlotId slotId)
-      throws InvalidRequestException {
+  public synchronized void registerSlot(ExtendedBlockId blockId, SlotId slotId,
+      boolean isCached) throws InvalidRequestException {
     if (!enabled) {
       if (LOG.isTraceEnabled()) {
-        LOG.trace("registerSlot: ShortCircuitRegistry is " +
-            "not enabled.");
+        LOG.trace(this + " can't register a slot because the " +
+            "ShortCircuitRegistry is not enabled.");
       }
       throw new UnsupportedOperationException();
     }
@@ -303,8 +303,17 @@ public class ShortCircuitRegistry {
           "registered with shmId " + shmId);
     }
     Slot slot = shm.registerSlot(slotId.getSlotIdx(), blockId);
+    if (isCached) {
+      slot.makeAnchorable();
+    } else {
+      slot.makeUnanchorable();
+    }
     boolean added = slots.put(blockId, slot);
     Preconditions.checkState(added);
+    if (LOG.isTraceEnabled()) {
+      LOG.trace(this + ": registered " + blockId + " with slot " +
+        slotId + " (isCached=" + isCached + ")");
+    }
   }
   
   public synchronized void unregisterSlot(SlotId slotId)

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

@@ -320,6 +320,14 @@ public interface FsDatasetSpi<V extends FsVolumeSpi> extends FSDatasetMBean {
    */
   public void uncache(String bpid, long[] blockIds);
 
+  /**
+   * Determine if the specified block is cached.
+   * @param bpid Block pool id
+   * @param blockIds - block id
+   * @returns true if the block is cached
+   */
+  public boolean isCached(String bpid, long blockId);
+
     /**
      * Check if all the data directories are healthy
      * @throws DiskErrorException

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetCache.java

@@ -473,4 +473,10 @@ public class FsDatasetCache {
   public long getNumBlocksCached() {
     return numBlocksCached.get();
   }
+
+  public synchronized boolean isCached(String bpid, long blockId) {
+    ExtendedBlockId block = new ExtendedBlockId(blockId, bpid);
+    Value val = mappableBlockMap.get(block);
+    return (val != null) && val.state.shouldAdvertise();
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java

@@ -1271,6 +1271,10 @@ class FsDatasetImpl implements FsDatasetSpi<FsVolumeImpl> {
     }
   }
 
+  public boolean isCached(String bpid, long blockId) {
+    return cacheManager.isCached(bpid, blockId);
+  }
+
   @Override // FsDatasetSpi
   public synchronized boolean contains(final ExtendedBlock block) {
     final long blockId = block.getLocalBlock().getBlockId();

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/CacheManager.java

@@ -916,10 +916,12 @@ public final class CacheManager {
     if (metrics != null) {
       metrics.addCacheBlockReport((int) (endTime - startTime));
     }
-    LOG.info("Processed cache report from "
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("Processed cache report from "
           + datanodeID + ", blocks: " + blockIds.size()
           + ", processing time: " + (endTime - startTime) + " msecs");
     }
+  }
 
   private void processCacheReportImpl(final DatanodeDescriptor datanode,
       final List<Long> blockIds) {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/fs/TestEnhancedByteBufferAccess.java

@@ -607,7 +607,7 @@ public class TestEnhancedByteBufferAccess {
     conf.setLong(DFS_DATANODE_MAX_LOCKED_MEMORY_KEY,
         DFSTestUtil.roundUpToMultiple(TEST_FILE_LENGTH, 4096));
     MiniDFSCluster cluster = null;
-    ByteBuffer result = null;
+    ByteBuffer result = null, result2 = null;
     cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1).build();
     cluster.waitActive();
     FsDatasetSpi<?> fsd = cluster.getDataNodes().get(0).getFSDataset();
@@ -644,9 +644,22 @@ public class TestEnhancedByteBufferAccess {
     } catch (UnsupportedOperationException e) {
       Assert.fail("expected to be able to read cached file via zero-copy");
     }
-    // Verify result
     Assert.assertArrayEquals(Arrays.copyOfRange(original, 0,
         BLOCK_SIZE), byteBufferToArray(result));
+    // Test that files opened after the cache operation has finished
+    // still get the benefits of zero-copy (regression test for HDFS-6086)
+    FSDataInputStream fsIn2 = fs.open(TEST_PATH);
+    try {
+      result2 = fsIn2.read(null, TEST_FILE_LENGTH,
+          EnumSet.noneOf(ReadOption.class));
+    } catch (UnsupportedOperationException e) {
+      Assert.fail("expected to be able to read cached file via zero-copy");
+    }
+    Assert.assertArrayEquals(Arrays.copyOfRange(original, 0,
+        BLOCK_SIZE), byteBufferToArray(result2));
+    fsIn2.releaseBuffer(result2);
+    fsIn2.close();
+    
     // check that the replica is anchored 
     final ExtendedBlock firstBlock =
         DFSTestUtil.getFirstBlock(fs, TEST_PATH);

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

@@ -641,6 +641,11 @@ public class SimulatedFSDataset implements FsDatasetSpi<FsVolumeSpi> {
         "SimulatedFSDataset does not support uncache operation!");
   }
 
+  @Override // FSDatasetSpi
+  public boolean isCached(String bpid, long blockId) {
+    return false;
+  }
+
   private BInfo getBInfo(final ExtendedBlock b) {
     final Map<Block, BInfo> map = blockMap.get(b.getBlockPoolId());
     return map == null? null: map.get(b.getLocalBlock());