/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hdfs.server.protocol;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.ipc.VersionedProtocol;
/** An inter-datanode protocol for updating generation stamp
*/
public interface InterDatanodeProtocol extends VersionedProtocol {
public static final Log LOG = LogFactory.getLog(InterDatanodeProtocol.class);
/**
* 4: added a new RPC to copy blocks between datanodes on the same host.
*/
public static final long versionID = 4L;
/** @return the BlockMetaDataInfo of a block;
* null if the block is not found
*/
BlockMetaDataInfo getBlockMetaDataInfo(int namespaceId, Block block) throws IOException;
/**
* Begin recovery on a block - this interrupts writers and returns the
* necessary metadata for recovery to begin.
* @return the BlockRecoveryInfo for a block
* @return null if the block is not found
*/
BlockRecoveryInfo startBlockRecovery(int namespaceId, Block block) throws IOException;
/**
* Update the block to the new generation stamp and length.
*/
void updateBlock(int namespaceId, Block oldblock, Block newblock, boolean finalize) throws IOException;
/**
* Copies a local block from a datanode on the same host.
*
* @param srcFileSystem
* the file system that the src block belongs to
* @param srcNamespaceId
* the namespaceId of srcBlock
* @param srcBlock
* the block that needs to be copied
* @param dstNamespaceId
* the namespaceId of dstBlock
* @param dstBlock
* the block to which the srcBlock needs to be copied
* @param srcBlockFile
* the absolute path to the block data file on the datanode
* @throws IOException
*/
void copyBlockLocal(String srcFileSystem, int srcNamespaceId, Block srcBlock,
int dstNamespaceId, Block dstBlock,
String srcBlockFilePath) throws IOException;
}