/**
* 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.datanode.fsdataset.impl;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.hdfs.DFSUtil;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.server.datanode.DataStorage;
import org.apache.hadoop.util.DiskChecker;
import org.apache.hadoop.util.DiskChecker.DiskErrorException;
/**
* A node type that can be built into a tree reflecting the
* hierarchy of replicas on the local disk.
*/
class LDir {
final File dir;
final int maxBlocksPerDir;
private int numBlocks = 0;
private LDir[] children = null;
private int lastChildIdx = 0;
LDir(File dir, int maxBlocksPerDir) throws IOException {
this.dir = dir;
this.maxBlocksPerDir = maxBlocksPerDir;
if (!dir.exists()) {
if (!dir.mkdirs()) {
throw new IOException("Failed to mkdirs " + dir);
}
} else {
File[] files = FileUtil.listFiles(dir);
List<LDir> dirList = new ArrayList<LDir>();
for (int idx = 0; idx < files.length; idx++) {
if (files[idx].isDirectory()) {
dirList.add(new LDir(files[idx], maxBlocksPerDir));
} else if (Block.isBlockFilename(files[idx])) {
numBlocks++;
}
}
if (dirList.size() > 0) {
children = dirList.toArray(new LDir[dirList.size()]);
}
}
}
File addBlock(Block b, File src) throws IOException {
//First try without creating subdirectories
File file = addBlock(b, src, false, false);
return (file != null) ? file : addBlock(b, src, true, true);
}
private File addBlock(Block b, File src, boolean createOk, boolean resetIdx
) throws IOException {
if (numBlocks < maxBlocksPerDir) {
final File dest = FsDatasetImpl.moveBlockFiles(b, src, dir);
numBlocks += 1;
return dest;
}
if (lastChildIdx < 0 && resetIdx) {
//reset so that all children will be checked
lastChildIdx = DFSUtil.getRandom().nextInt(children.length);
}
if (lastChildIdx >= 0 && children != null) {
//Check if any child-tree has room for a block.
for (int i=0; i < children.length; i++) {
int idx = (lastChildIdx + i)%children.length;
File file = children[idx].addBlock(b, src, false, resetIdx);
if (file != null) {
lastChildIdx = idx;
return file;
}
}
lastChildIdx = -1;
}
if (!createOk) {
return null;
}
if (children == null || children.length == 0) {
children = new LDir[maxBlocksPerDir];
for (int idx = 0; idx < maxBlocksPerDir; idx++) {
final File sub = new File(dir, DataStorage.BLOCK_SUBDIR_PREFIX+idx);
children[idx] = new LDir(sub, maxBlocksPerDir);
}
}
//now pick a child randomly for creating a new set of subdirs.
lastChildIdx = DFSUtil.getRandom().nextInt(children.length);
return children[ lastChildIdx ].addBlock(b, src, true, false);
}
void getVolumeMap(String bpid, ReplicaMap volumeMap, FsVolumeImpl volume
) throws IOException {
if (children != null) {
for (int i = 0; i < children.length; i++) {
children[i].getVolumeMap(bpid, volumeMap, volume);
}
}
recoverTempUnlinkedBlock();
volume.addToReplicasMap(bpid, volumeMap, dir, true);
}
/**
* Recover unlinked tmp files on datanode restart. If the original block
* does not exist, then the tmp file is renamed to be the
* original file name; otherwise the tmp file is deleted.
*/
private void recoverTempUnlinkedBlock() throws IOException {
File files[] = FileUtil.listFiles(dir);
for (File file : files) {
if (!FsDatasetUtil.isUnlinkTmpFile(file)) {
continue;
}
File blockFile = FsDatasetUtil.getOrigFile(file);
if (blockFile.exists()) {
// If the original block file still exists, then no recovery is needed.
if (!file.delete()) {
throw new IOException("Unable to cleanup unlinked tmp file " + file);
}
} else {
if (!file.renameTo(blockFile)) {
throw new IOException("Unable to cleanup detached file " + file);
}
}
}
}
/**
* check if a data diretory is healthy
* @throws DiskErrorException
*/
void checkDirTree() throws DiskErrorException {
DiskChecker.checkDir(dir);
if (children != null) {
for (int i = 0; i < children.length; i++) {
children[i].checkDirTree();
}
}
}
void clearPath(File f) {
String root = dir.getAbsolutePath();
String dir = f.getAbsolutePath();
if (dir.startsWith(root)) {
String[] dirNames = dir.substring(root.length()).
split(File.separator + DataStorage.BLOCK_SUBDIR_PREFIX);
if (clearPath(f, dirNames, 1))
return;
}
clearPath(f, null, -1);
}
/**
* dirNames is an array of string integers derived from
* usual directory structure data/subdirN/subdirXY/subdirM ...
* If dirName array is non-null, we only check the child at
* the children[dirNames[idx]]. This avoids iterating over
* children in common case. If directory structure changes
* in later versions, we need to revisit this.
*/
private boolean clearPath(File f, String[] dirNames, int idx) {
if ((dirNames == null || idx == dirNames.length) &&
dir.compareTo(f) == 0) {
numBlocks--;
return true;
}
if (dirNames != null) {
//guess the child index from the directory name
if (idx > (dirNames.length - 1) || children == null) {
return false;
}
int childIdx;
try {
childIdx = Integer.parseInt(dirNames[idx]);
} catch (NumberFormatException ignored) {
// layout changed? we could print a warning.
return false;
}
return (childIdx >= 0 && childIdx < children.length) ?
children[childIdx].clearPath(f, dirNames, idx+1) : false;
}
//guesses failed. back to blind iteration.
if (children != null) {
for(int i=0; i < children.length; i++) {
if (children[i].clearPath(f, null, -1)){
return true;
}
}
}
return false;
}
@Override
public String toString() {
return "FSDir{dir=" + dir + ", children="
+ (children == null ? null : Arrays.asList(children)) + "}";
}
}