ayushtkn commented on a change in pull request #1819: HDFS-14989. Add a 'swapBlockList' operation to Namenode. URL: https://github.com/apache/hadoop/pull/1819#discussion_r372980350
########## File path: hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SwapBlockListOp.java ########## @@ -0,0 +1,190 @@ +/** + * 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.namenode; + +import java.io.FileNotFoundException; +import java.io.IOException; + +import org.apache.hadoop.fs.FileAlreadyExistsException; +import org.apache.hadoop.fs.FileStatus; +import org.apache.hadoop.fs.permission.FsAction; +import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo; +import org.apache.hadoop.hdfs.server.namenode.FSDirectory.DirOp; +import org.apache.hadoop.hdfs.server.namenode.INodeFile.HeaderFormat; +import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot; +import org.apache.hadoop.util.Time; + +/** + * Class to carry out the operation of swapping blocks from one file to another. + * Along with swapping blocks, we can also optionally swap the block layout + * of a file header, which is useful for client operations like converting + * replicated to EC file. + */ +public final class SwapBlockListOp { + + private SwapBlockListOp() { + } + + static SwapBlockListResult swapBlocks(FSDirectory fsd, FSPermissionChecker pc, + String src, String dst, long genTimestamp) + throws IOException { + + final INodesInPath srcIIP = fsd.resolvePath(pc, src, DirOp.WRITE); + final INodesInPath dstIIP = fsd.resolvePath(pc, dst, DirOp.WRITE); + if (fsd.isPermissionEnabled()) { + fsd.checkAncestorAccess(pc, srcIIP, FsAction.WRITE); + fsd.checkAncestorAccess(pc, dstIIP, FsAction.WRITE); + } + if (NameNode.stateChangeLog.isDebugEnabled()) { + NameNode.stateChangeLog.debug("DIR* FSDirectory.swapBlockList: " + + srcIIP.getPath() + " and " + dstIIP.getPath()); + } + SwapBlockListResult result = null; + fsd.writeLock(); + try { + result = swapBlockList(fsd, srcIIP, dstIIP, genTimestamp); + } finally { + fsd.writeUnlock(); + } + return result; + } + + private static SwapBlockListResult swapBlockList(FSDirectory fsd, + final INodesInPath srcIIP, + final INodesInPath dstIIP, + long genTimestamp) + throws IOException { + + assert fsd.hasWriteLock(); + validateInode(srcIIP); + validateInode(dstIIP); + fsd.ezManager.checkMoveValidity(srcIIP, dstIIP); + + final String src = srcIIP.getPath(); + final String dst = dstIIP.getPath(); + if (dst.equals(src)) { + throw new FileAlreadyExistsException("The source " + src + + " and destination " + dst + " are the same"); + } + + INodeFile srcINodeFile = (INodeFile) srcIIP.getLastINode(); + INodeFile dstINodeFile = (INodeFile) dstIIP.getLastINode(); + + String errorPrefix = "DIR* FSDirectory.swapBlockList: "; + String error = "Swap Block List destination file "; + BlockInfo lastBlock = dstINodeFile.getLastBlock(); + if (lastBlock != null && lastBlock.getGenerationStamp() != genTimestamp) { + error += dstIIP.getPath() + + " has last block with different gen timestamp."; + NameNode.stateChangeLog.warn(errorPrefix + error); + throw new IOException(error); + } + + long mtime = Time.now(); + BlockInfo[] dstINodeFileBlocks = dstINodeFile.getBlocks(); + dstINodeFile.replaceBlocks(srcINodeFile.getBlocks()); + srcINodeFile.replaceBlocks(dstINodeFileBlocks); Review comment: I meant just refactor this too, srcINodeFile.getBlocks() as you did for dstINodeFile.getBlocks() into a variable, to match the code style with srcINodeFile.replaceBlocks(dstINodeFileBlocks); Optional stuff, If you prefer to do. :) ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org
