| /** |
| * 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; |
| |
| import java.io.File; |
| import java.io.FileInputStream; |
| import java.io.FileNotFoundException; |
| import java.io.IOException; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.hdfs.protocol.Block; |
| import org.apache.hadoop.hdfs.protocol.ExtendedBlock; |
| import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi; |
| import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi; |
| import org.apache.hadoop.hdfs.server.datanode.fsdataset.LengthInputStream; |
| |
| /** Provide utility methods for Datanode. */ |
| @InterfaceAudience.Private |
| public class DatanodeUtil { |
| public static final String UNLINK_BLOCK_SUFFIX = ".unlinked"; |
| |
| public static final String DISK_ERROR = "Possible disk error: "; |
| |
| private static final String SEP = System.getProperty("file.separator"); |
| |
| /** Get the cause of an I/O exception if caused by a possible disk error |
| * @param ioe an I/O exception |
| * @return cause if the I/O exception is caused by a possible disk error; |
| * null otherwise. |
| */ |
| static IOException getCauseIfDiskError(IOException ioe) { |
| if (ioe.getMessage()!=null && ioe.getMessage().startsWith(DISK_ERROR)) { |
| return (IOException)ioe.getCause(); |
| } else { |
| return null; |
| } |
| } |
| |
| /** |
| * Create a new file. |
| * @throws IOException |
| * if the file already exists or if the file cannot be created. |
| */ |
| public static File createFileWithExistsCheck( |
| FsVolumeSpi volume, Block b, File f, |
| FileIoProvider fileIoProvider) throws IOException { |
| if (fileIoProvider.exists(volume, f)) { |
| throw new IOException("Failed to create temporary file for " + b |
| + ". File " + f + " should not be present, but is."); |
| } |
| // Create the zero-length temp file |
| final boolean fileCreated; |
| try { |
| fileCreated = fileIoProvider.createFile(volume, f); |
| } catch (IOException ioe) { |
| throw new IOException(DISK_ERROR + "Failed to create " + f, ioe); |
| } |
| if (!fileCreated) { |
| throw new IOException("Failed to create temporary file for " + b |
| + ". File " + f + " should be creatable, but is already present."); |
| } |
| return f; |
| } |
| |
| /** |
| * @return the meta name given the block name and generation stamp. |
| */ |
| public static String getMetaName(String blockName, long generationStamp) { |
| return blockName + "_" + generationStamp + Block.METADATA_EXTENSION; |
| } |
| |
| /** @return the unlink file. */ |
| public static File getUnlinkTmpFile(File f) { |
| return new File(f.getParentFile(), f.getName()+UNLINK_BLOCK_SUFFIX); |
| } |
| |
| /** |
| * Checks whether there are any files anywhere in the directory tree rooted |
| * at dir (directories don't count as files). dir must exist |
| * @return true if there are no files |
| * @throws IOException if unable to list subdirectories |
| */ |
| public static boolean dirNoFilesRecursive( |
| FsVolumeSpi volume, File dir, |
| FileIoProvider fileIoProvider) throws IOException { |
| File[] contents = fileIoProvider.listFiles(volume, dir); |
| if (contents == null) { |
| throw new IOException("Cannot list contents of " + dir); |
| } |
| for (File f : contents) { |
| if (!f.isDirectory() || |
| (f.isDirectory() && !dirNoFilesRecursive( |
| volume, f, fileIoProvider))) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /** |
| * Get the directory where a finalized block with this ID should be stored. |
| * Do not attempt to create the directory. |
| * @param root the root directory where finalized blocks are stored |
| * @param blockId |
| * @return |
| */ |
| public static File idToBlockDir(File root, long blockId) { |
| int d1 = (int) ((blockId >> 16) & 0x1F); |
| int d2 = (int) ((blockId >> 8) & 0x1F); |
| String path = DataStorage.BLOCK_SUBDIR_PREFIX + d1 + SEP + |
| DataStorage.BLOCK_SUBDIR_PREFIX + d2; |
| return new File(root, path); |
| } |
| |
| /** |
| * @return the FileInputStream for the meta data of the given block. |
| * @throws FileNotFoundException |
| * if the file not found. |
| * @throws ClassCastException |
| * if the underlying input stream is not a FileInputStream. |
| */ |
| public static FileInputStream getMetaDataInputStream( |
| ExtendedBlock b, FsDatasetSpi<?> data) throws IOException { |
| final LengthInputStream lin = data.getMetaDataInputStream(b); |
| if (lin == null) { |
| throw new FileNotFoundException("Meta file for " + b + " not found."); |
| } |
| return (FileInputStream)lin.getWrappedStream(); |
| } |
| |
| /** |
| * Call fsync on specified directories to sync metadata changes. |
| * @param fileIoProvider |
| * @param volume |
| * @param dirs |
| * @throws IOException |
| */ |
| public static void fsyncDirectory(FileIoProvider fileIoProvider, |
| FsVolumeSpi volume, File... dirs) throws IOException { |
| for (File dir : dirs) { |
| try { |
| fileIoProvider.dirSync(volume, dir); |
| } catch (IOException e) { |
| throw new IOException("Failed to sync " + dir, e); |
| } |
| } |
| } |
| } |