HDDS-211. Add a create container Lock. Contributed by Bharat Viswanadham

hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/impl/HddsDispatcher.java

@@ -119,8 +119,10 @@ public ContainerCommandResponseProto dispatch(
     responseProto = handler.handle(msg, container);
     if (responseProto != null) {
       metrics.incContainerOpsLatencies(cmdType, System.nanoTime() - startTime);
-    }
       return responseProto;
+    } else {
+      return ContainerUtils.unsupportedRequest(msg);
+    }
   }
 
   @Override

hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/interfaces/Handler.java

@@ -36,7 +36,7 @@
  * Dispatcher sends ContainerCommandRequests to Handler. Each Container Type
  * should have an implementation for Handler.
  */
-public class Handler {
+public abstract class Handler {
 
   protected final Configuration conf;
   protected final ContainerSet containerSet;
@@ -64,10 +64,8 @@ public static Handler getHandlerForContainerType(ContainerType containerType,
     }
   }
 
-  public ContainerCommandResponseProto handle(
+  public abstract ContainerCommandResponseProto handle(
-      ContainerCommandRequestProto msg, Container container) {
+      ContainerCommandRequestProto msg, Container container);
-    return null;
-  }
 
   public void setScmID(String scmId) {
     this.scmID = scmId;

hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/keyvalue/KeyValueHandler.java

@@ -62,6 +62,7 @@
 import org.apache.hadoop.ozone.container.keyvalue.helpers.KeyUtils;
 import org.apache.hadoop.ozone.container.keyvalue.interfaces.ChunkManager;
 import org.apache.hadoop.ozone.container.keyvalue.interfaces.KeyManager;
+import org.apache.hadoop.util.AutoCloseableLock;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -70,6 +71,7 @@
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.locks.ReentrantLock;
 
 import static org.apache.hadoop.hdds.protocol.datanode.proto.ContainerProtos
     .Result.CONTAINER_INTERNAL_ERROR;
@@ -102,6 +104,7 @@ public class KeyValueHandler extends Handler {
   private final ChunkManager chunkManager;
   private VolumeChoosingPolicy volumeChoosingPolicy;
   private final int maxContainerSizeGB;
+  private final AutoCloseableLock handlerLock;
 
 
   public KeyValueHandler(Configuration config, ContainerSet contSet,
@@ -115,6 +118,9 @@ public KeyValueHandler(Configuration config, ContainerSet contSet,
     maxContainerSizeGB = config.getInt(ScmConfigKeys
             .OZONE_SCM_CONTAINER_SIZE_GB, ScmConfigKeys
         .OZONE_SCM_CONTAINER_SIZE_DEFAULT);
+    // this handler lock is used for synchronizing createContainer Requests,
+    // so using a fair lock here.
+    handlerLock = new AutoCloseableLock(new ReentrantLock(true));
   }
 
   @Override
@@ -159,7 +165,6 @@ public ContainerCommandResponseProto handle(
     case GetSmallFile:
       return handleGetSmallFile(request, kvContainer);
     }
-
     return null;
   }
 
@@ -204,10 +209,19 @@ ContainerCommandResponseProto handleCreateContainer(
         newContainerData, conf);
 
     try {
+      handlerLock.acquire();
+      if (containerSet.getContainer(containerID) == null) {
         newContainer.create(volumeSet, volumeChoosingPolicy, scmID);
         containerSet.addContainer(newContainer);
+      } else {
+        throw new StorageContainerException("Container already exists with " +
+            "container Id " + containerID, ContainerProtos.Result
+            .CONTAINER_EXISTS);
+      }
     } catch (StorageContainerException ex) {
       return ContainerUtils.logAndReturnError(LOG, ex, request);
+    } finally {
+      handlerLock.release();
     }
 
     return ContainerUtils.getSuccessResponse(request);

hadoop-ozone/tools/src/main/java/org/apache/hadoop/ozone/genesis/BenchMarkDatanodeDispatcher.java

@@ -28,7 +28,6 @@
 import org.apache.commons.lang3.RandomUtils;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdds.client.BlockID;
-import org.apache.hadoop.hdfs.server.datanode.StorageLocation;
 import org.apache.hadoop.hdds.conf.OzoneConfiguration;
 
 import org.apache.hadoop.util.Time;
@@ -42,13 +41,11 @@
 import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.List;
 import java.util.Random;
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import static org.apache.hadoop.ozone.OzoneConsts.CONTAINER_ROOT_PREFIX;
 
 import org.apache.hadoop.hdds.protocol.proto.HddsProtos.LifeCycleState;
 import org.apache.hadoop.hdds.protocol.datanode.proto.ContainerProtos
@@ -106,10 +103,6 @@ public void initialize() throws IOException {
     // data directory
     conf.set("dfs.datanode.data.dir", baseDir + File.separator + "data");
 
-    // metadata directory
-    StorageLocation metadataDir = StorageLocation.parse(
-        baseDir + File.separator + CONTAINER_ROOT_PREFIX);
-
     ContainerSet containerSet = new ContainerSet();
     VolumeSet volumeSet = new VolumeSet(datanodeUuid, conf);