/**
* 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.util;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicReference;
import com.google.common.annotations.VisibleForTesting;
import org.apache.commons.io.FileUtils;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.fs.LocalFileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Class that provides utility functions for checking disk problem
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
public class DiskChecker {
public static final Logger LOG = LoggerFactory.getLogger(DiskChecker.class);
public static class DiskErrorException extends IOException {
public DiskErrorException(String msg) {
super(msg);
}
public DiskErrorException(String msg, Throwable cause) {
super(msg, cause);
}
}
public static class DiskOutOfSpaceException extends IOException {
public DiskOutOfSpaceException(String msg) {
super(msg);
}
}
// Provider that abstracts some FileOutputStream operations for
// testability.
private static AtomicReference<FileIoProvider> fileIoProvider =
new AtomicReference<FileIoProvider>(new DefaultFileIoProvider());
/**
* Create the directory if it doesn't exist and check that dir is readable,
* writable and executable
*
* @param dir
* @throws DiskErrorException
*/
public static void checkDir(File dir) throws DiskErrorException {
if (!mkdirsWithExistsCheck(dir)) {
throw new DiskErrorException("Cannot create directory: "
+ dir.toString());
}
checkAccessByFileMethods(dir);
doDiskIo(dir);
}
/**
* Create the local directory if necessary, check permissions and also ensure
* it can be read from and written into.
*
* @param localFS local filesystem
* @param dir directory
* @param expected permission
* @throws DiskErrorException
* @throws IOException
*/
public static void checkDir(LocalFileSystem localFS, Path dir,
FsPermission expected)
throws DiskErrorException, IOException {
mkdirsWithExistsAndPermissionCheck(localFS, dir, expected);
checkAccessByFileMethods(localFS.pathToFile(dir));
doDiskIo(localFS.pathToFile(dir));
}
/**
* Checks that the current running process can read, write, and execute the
* given directory by using methods of the File object.
*
* @param dir File to check
* @throws DiskErrorException if dir is not readable, not writable, or not
* executable
*/
private static void checkAccessByFileMethods(File dir)
throws DiskErrorException {
if (!dir.isDirectory()) {
throw new DiskErrorException("Not a directory: "
+ dir.toString());
}
if (!FileUtil.canRead(dir)) {
throw new DiskErrorException("Directory is not readable: "
+ dir.toString());
}
if (!FileUtil.canWrite(dir)) {
throw new DiskErrorException("Directory is not writable: "
+ dir.toString());
}
if (!FileUtil.canExecute(dir)) {
throw new DiskErrorException("Directory is not executable: "
+ dir.toString());
}
}
/**
* The semantics of mkdirsWithExistsCheck method is different from the mkdirs
* method provided in the Sun's java.io.File class in the following way:
* While creating the non-existent parent directories, this method checks for
* the existence of those directories if the mkdir fails at any point (since
* that directory might have just been created by some other process).
* If both mkdir() and the exists() check fails for any seemingly
* non-existent directory, then we signal an error; Sun's mkdir would signal
* an error (return false) if a directory it is attempting to create already
* exists or the mkdir fails.
* @param dir
* @return true on success, false on failure
*/
private static boolean mkdirsWithExistsCheck(File dir) {
if (dir.mkdir() || dir.exists()) {
return true;
}
File canonDir;
try {
canonDir = dir.getCanonicalFile();
} catch (IOException e) {
return false;
}
String parent = canonDir.getParent();
return (parent != null) &&
(mkdirsWithExistsCheck(new File(parent)) &&
(canonDir.mkdir() || canonDir.exists()));
}
/**
* Create the directory or check permissions if it already exists.
*
* The semantics of mkdirsWithExistsAndPermissionCheck method is different
* from the mkdirs method provided in the Sun's java.io.File class in the
* following way:
* While creating the non-existent parent directories, this method checks for
* the existence of those directories if the mkdir fails at any point (since
* that directory might have just been created by some other process).
* If both mkdir() and the exists() check fails for any seemingly
* non-existent directory, then we signal an error; Sun's mkdir would signal
* an error (return false) if a directory it is attempting to create already
* exists or the mkdir fails.
*
* @param localFS local filesystem
* @param dir directory to be created or checked
* @param expected expected permission
* @throws IOException
*/
static void mkdirsWithExistsAndPermissionCheck(
LocalFileSystem localFS, Path dir, FsPermission expected)
throws IOException {
File directory = localFS.pathToFile(dir);
boolean created = false;
if (!directory.exists())
created = mkdirsWithExistsCheck(directory);
if (created || !localFS.getFileStatus(dir).getPermission().equals(expected))
localFS.setPermission(dir, expected);
}
// State related to running disk IO checks.
private static final String DISK_IO_FILE_PREFIX =
"DiskChecker.OK_TO_DELETE_.";
@VisibleForTesting
static final int DISK_IO_MAX_ITERATIONS = 3;
/**
* Performs some disk IO by writing to a new file in the given directory
* and sync'ing file contents to disk.
*
* This increases the likelihood of catching catastrophic disk/controller
* failures sooner.
*
* @param dir directory to be checked.
* @throws DiskErrorException if we hit an error while trying to perform
* disk IO against the file.
*/
private static void doDiskIo(File dir) throws DiskErrorException {
try {
IOException ioe = null;
for (int i = 0; i < DISK_IO_MAX_ITERATIONS; ++i) {
final File file = getFileNameForDiskIoCheck(dir, i+1);
try {
diskIoCheckWithoutNativeIo(file);
return;
} catch (IOException e) {
// Let's retry a few times before we really give up and
// declare the disk as bad.
ioe = e;
}
}
throw ioe; // Just rethrow the last exception to signal failure.
} catch(IOException e) {
throw new DiskErrorException("Error checking directory " + dir, e);
}
}
/**
* Try to perform some disk IO by writing to the given file
* without using Native IO.
*
* @param file
* @throws IOException if there was a non-retriable error.
*/
private static void diskIoCheckWithoutNativeIo(File file)
throws IOException {
FileOutputStream fos = null;
try {
final FileIoProvider provider = fileIoProvider.get();
fos = provider.get(file);
provider.write(fos, new byte[1]);
fos.getFD().sync();
fos.close();
fos = null;
if (!file.delete() && file.exists()) {
throw new IOException("Failed to delete " + file);
}
file = null;
} finally {
IOUtils.cleanup(null, fos);
FileUtils.deleteQuietly(file);
}
}
/**
* Generate a path name for a test file under the given directory.
*
* @return file object.
*/
@VisibleForTesting
static File getFileNameForDiskIoCheck(File dir, int iterationCount) {
if (iterationCount < DISK_IO_MAX_ITERATIONS) {
// Use file names of the format prefix.001 by default.
return new File(dir,
DISK_IO_FILE_PREFIX + String.format("%03d", iterationCount));
} else {
// If the first few checks then fail, try using a randomly generated
// file name.
return new File(dir, DISK_IO_FILE_PREFIX + UUID.randomUUID());
}
}
/**
* An interface that abstracts operations on {@link FileOutputStream}
* objects for testability.
*/
interface FileIoProvider {
FileOutputStream get(File f) throws FileNotFoundException;
void write(FileOutputStream fos, byte[] data) throws IOException;
}
/**
* The default implementation of {@link FileIoProvider}.
*/
private static class DefaultFileIoProvider implements FileIoProvider {
/**
* See {@link FileOutputStream#FileOutputStream(File)}.
*/
@Override
public FileOutputStream get(File f) throws FileNotFoundException {
return new FileOutputStream(f);
}
/**
* See {@link FileOutputStream#write(byte[])}.
*/
@Override
public void write(FileOutputStream fos, byte[] data) throws IOException {
fos.write(data);
}
}
/**
* Replace the {@link FileIoProvider} for tests.
* This method MUST NOT be used outside of unit tests.
*
* @param newFosProvider
* @return the old FileIoProvider.
*/
@VisibleForTesting
static FileIoProvider replaceFileOutputStreamProvider(
FileIoProvider newFosProvider) {
return fileIoProvider.getAndSet(newFosProvider);
}
/**
* Retrieve the current {@link FileIoProvider}.
* This method MUST NOT be used outside of unit tests.
*
* @return the current FileIoProvider.
*/
@VisibleForTesting
static FileIoProvider getFileOutputStreamProvider() {
return fileIoProvider.get();
}
}