HDFS-4083. Protocol changes for snapshots. Contributed by Suresh Srinivas.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-2802@1400316 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-2802.txt

@@ -8,4 +8,4 @@ Branch-2802 Snapshot (Unreleased)
   HDFS-4086. Add editlog opcodes to allow and disallow snapshots on a 
   directory. (Brandon Li via suresh)
 
-
+  HDFS-4083. Protocol changes for snapshots. (suresh)

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

@@ -949,4 +949,20 @@ public void cancelDelegationToken(Token<DelegationTokenIdentifier> token)
    * @throws IOException
    */
   public DataEncryptionKey getDataEncryptionKey() throws IOException;
+  
+  /**
+   * Create a snapshot
+   * @param snapshotName name of the snapshot created
+   * @param snapshotRoot the path that is being snapshotted
+   */
+  public void createSnapshot(String snapshotName, String snapshotRoot)
+      throws IOException;
+  
+  /**
+   * Delete a snapshot
+   * @param snapshotName name of the snapshot to be deleted
+   * @param snapshotRoot the path where the snapshot exists
+   */
+  public void deleteSnapshot(String snapshotName, String snapshotRoot)
+      throws IOException;
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolServerSideTranslatorPB.java

@@ -46,10 +46,14 @@
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ConcatResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateSnapshotRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateSnapshotResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateSymlinkRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateSymlinkResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.DeleteRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.DeleteResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.DeleteSnapshotRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.DeleteSnapshotResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.FinalizeUpgradeRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.FinalizeUpgradeResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.FsyncRequestProto;
@@ -83,6 +87,8 @@
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetServerDefaultsResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCorruptFileBlocksRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCorruptFileBlocksResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListSnapshotsRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListSnapshotsResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MetaSaveRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MetaSaveResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MkdirsRequestProto;
@@ -147,6 +153,11 @@
 public class ClientNamenodeProtocolServerSideTranslatorPB implements
     ClientNamenodeProtocolPB {
   final private ClientProtocol server;
+  static final DeleteSnapshotResponseProto VOID_DELETE_SNAPSHOT_RESPONSE =
+      DeleteSnapshotResponseProto.newBuilder().build();
+  static final CreateSnapshotResponseProto VOID_CREATE_SNAPSHOT_RESPONSE =
+      CreateSnapshotResponseProto.newBuilder().build();
+  
 
   /**
    * Constructor
@@ -842,4 +853,35 @@ public GetDataEncryptionKeyResponseProto getDataEncryptionKey(
       throw new ServiceException(e);
     }
   }
+
+  @Override
+  public CreateSnapshotResponseProto createSnapshot(RpcController controller,
+      CreateSnapshotRequestProto request) throws ServiceException {
+    try {
+      server.createSnapshot(request.getSnapshotName(),
+          request.getSnapshotRoot());
+    } catch (IOException e) {
+      throw new ServiceException(e);
+    }
+    return VOID_CREATE_SNAPSHOT_RESPONSE;
+  }
+
+  @Override
+  public DeleteSnapshotResponseProto deleteSnapshot(RpcController controller,
+      DeleteSnapshotRequestProto request) throws ServiceException {
+    try {
+      server.deleteSnapshot(request.getSnapshotName(),
+          request.getSnapshotRoot());
+    } catch (IOException e) {
+      throw new ServiceException(e);
+    }
+    return VOID_DELETE_SNAPSHOT_RESPONSE;
+  }
+
+  @Override
+  public ListSnapshotsResponseProto listSnapshots(RpcController controller,
+      ListSnapshotsRequestProto request) throws ServiceException {
+    // TODO Auto-generated method stub
+    return null;
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolTranslatorPB.java

@@ -55,8 +55,10 @@
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CompleteRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ConcatRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateSnapshotRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateSymlinkRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.DeleteRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.DeleteSnapshotRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.FinalizeUpgradeRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.FsyncRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetAdditionalDatanodeRequestProto;
@@ -828,4 +830,28 @@ public Object getUnderlyingProxyObject() {
     return rpcProxy;
   }
 
+  @Override
+  public void createSnapshot(String snapshotName, String snapshotRoot)
+      throws IOException {
+    CreateSnapshotRequestProto req = CreateSnapshotRequestProto.newBuilder()
+        .setSnapshotName(snapshotName).setSnapshotRoot(snapshotRoot).build();
+    try {
+      rpcProxy.createSnapshot(null, req);
+    } catch (ServiceException e) {
+      throw ProtobufHelper.getRemoteException(e);
+    }
+  }
+
+  @Override
+  public void deleteSnapshot(String snapshotName, String snapshotRoot)
+      throws IOException {
+    DeleteSnapshotRequestProto req = DeleteSnapshotRequestProto.newBuilder()
+        .setSnapshotName(snapshotName).setSnapshotRoot(snapshotRoot).build();
+    try {
+      rpcProxy.deleteSnapshot(null, req);
+    } catch (ServiceException e) {
+      throw ProtobufHelper.getRemoteException(e);
+    }
+    
+  }
 }

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

@@ -1072,4 +1072,16 @@ private static String getClientMachine() {
   public DataEncryptionKey getDataEncryptionKey() throws IOException {
     return namesystem.getBlockManager().generateDataEncryptionKey();
   }
+
+  @Override
+  public void createSnapshot(String snapshotName, String snapshotRoot)
+      throws IOException {
+    // TODO Auto-generated method stub
+  }
+
+  @Override
+  public void deleteSnapshot(String snapshotName, String snapshotRoot)
+      throws IOException {
+    // TODO Auto-generated method stub
+  }
 }

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

@@ -442,6 +442,30 @@ message GetDataEncryptionKeyResponseProto {
   required DataEncryptionKeyProto dataEncryptionKey = 1;
 }
 
+message CreateSnapshotRequestProto {
+  required string snapshotName = 1;
+  required string snapshotRoot = 2;
+}
+
+message CreateSnapshotResponseProto { // void response
+}
+
+message DeleteSnapshotRequestProto {
+  required string snapshotName = 1;
+  required string snapshotRoot = 2;
+}
+
+message DeleteSnapshotResponseProto { // void response
+}
+
+message ListSnapshotsRequestProto {
+  required string snapshotRoot = 1;
+}
+
+message ListSnapshotsResponseProto {
+  repeated SnapshotInfoProto snapshots = 1;
+}
+
 service ClientNamenodeProtocol {
   rpc getBlockLocations(GetBlockLocationsRequestProto)
       returns(GetBlockLocationsResponseProto);
@@ -515,4 +539,10 @@ service ClientNamenodeProtocol {
       returns(SetBalancerBandwidthResponseProto);
   rpc getDataEncryptionKey(GetDataEncryptionKeyRequestProto)
       returns(GetDataEncryptionKeyResponseProto);
+  rpc createSnapshot(CreateSnapshotRequestProto)
+      returns(CreateSnapshotResponseProto);
+  rpc deleteSnapshot(DeleteSnapshotRequestProto)
+      returns(DeleteSnapshotResponseProto);
+  rpc listSnapshots(ListSnapshotsRequestProto)
+      returns(ListSnapshotsResponseProto);
 }

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

@@ -375,3 +375,15 @@ message VersionResponseProto {
   required NamespaceInfoProto info = 1;
 }
 
+/**
+ * Information related to a snapshot
+ * TODO: add more information
+ */
+message SnapshotInfoProto {
+  required string snapshotName = 1;
+  required FsPermissionProto permission = 2;
+  required string owner = 3;
+  required string group = 4;
+  // TODO: do we need access time?
+}
+