org.apache.hadoop.fs.ChecksumFileSystem Maven / Gradle / Ivy
Show all versions of hadoop-apache Show documentation
/**
* 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.fs;
import java.io.EOFException;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.nio.channels.ClosedChannelException;
import java.util.Arrays;
import java.util.List;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.permission.AclEntry;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.util.DataChecksum;
import org.apache.hadoop.util.Progressable;
/****************************************************************
* Abstract Checksumed FileSystem.
* It provide a basic implementation of a Checksumed FileSystem,
* which creates a checksum file for each raw file.
* It generates & verifies checksums at the client side.
*
*****************************************************************/
@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class ChecksumFileSystem extends FilterFileSystem {
private static final byte[] CHECKSUM_VERSION = new byte[] {'c', 'r', 'c', 0};
private int bytesPerChecksum = 512;
private boolean verifyChecksum = true;
private boolean writeChecksum = true;
public static double getApproxChkSumLength(long size) {
return ChecksumFSOutputSummer.CHKSUM_AS_FRACTION * size;
}
public ChecksumFileSystem(FileSystem fs) {
super(fs);
}
@Override
public void setConf(Configuration conf) {
super.setConf(conf);
if (conf != null) {
bytesPerChecksum = conf.getInt(LocalFileSystemConfigKeys.LOCAL_FS_BYTES_PER_CHECKSUM_KEY,
LocalFileSystemConfigKeys.LOCAL_FS_BYTES_PER_CHECKSUM_DEFAULT);
}
}
/**
* Set whether to verify checksum.
*/
@Override
public void setVerifyChecksum(boolean verifyChecksum) {
this.verifyChecksum = verifyChecksum;
}
@Override
public void setWriteChecksum(boolean writeChecksum) {
this.writeChecksum = writeChecksum;
}
/** get the raw file system */
@Override
public FileSystem getRawFileSystem() {
return fs;
}
/** Return the name of the checksum file associated with a file.*/
public Path getChecksumFile(Path file) {
return new Path(file.getParent(), "." + file.getName() + ".crc");
}
/** Return true iff file is a checksum file name.*/
public static boolean isChecksumFile(Path file) {
String name = file.getName();
return name.startsWith(".") && name.endsWith(".crc");
}
/** Return the length of the checksum file given the size of the
* actual file.
**/
public long getChecksumFileLength(Path file, long fileSize) {
return getChecksumLength(fileSize, getBytesPerSum());
}
/** Return the bytes Per Checksum */
public int getBytesPerSum() {
return bytesPerChecksum;
}
private int getSumBufferSize(int bytesPerSum, int bufferSize) {
int defaultBufferSize = getConf().getInt(
LocalFileSystemConfigKeys.LOCAL_FS_STREAM_BUFFER_SIZE_KEY,
LocalFileSystemConfigKeys.LOCAL_FS_STREAM_BUFFER_SIZE_DEFAULT);
int proportionalBufferSize = bufferSize / bytesPerSum;
return Math.max(bytesPerSum,
Math.max(proportionalBufferSize, defaultBufferSize));
}
/*******************************************************
* For open()'s FSInputStream
* It verifies that data matches checksums.
*******************************************************/
private static class ChecksumFSInputChecker extends FSInputChecker {
private ChecksumFileSystem fs;
private FSDataInputStream datas;
private FSDataInputStream sums;
private static final int HEADER_LENGTH = 8;
private int bytesPerSum = 1;
public ChecksumFSInputChecker(ChecksumFileSystem fs, Path file)
throws IOException {
this(fs, file, fs.getConf().getInt(
LocalFileSystemConfigKeys.LOCAL_FS_STREAM_BUFFER_SIZE_KEY,
LocalFileSystemConfigKeys.LOCAL_FS_STREAM_BUFFER_SIZE_DEFAULT));
}
public ChecksumFSInputChecker(ChecksumFileSystem fs, Path file, int bufferSize)
throws IOException {
super( file, fs.getFileStatus(file).getReplication() );
this.datas = fs.getRawFileSystem().open(file, bufferSize);
this.fs = fs;
Path sumFile = fs.getChecksumFile(file);
try {
int sumBufferSize = fs.getSumBufferSize(fs.getBytesPerSum(), bufferSize);
sums = fs.getRawFileSystem().open(sumFile, sumBufferSize);
byte[] version = new byte[CHECKSUM_VERSION.length];
sums.readFully(version);
if (!Arrays.equals(version, CHECKSUM_VERSION))
throw new IOException("Not a checksum file: "+sumFile);
this.bytesPerSum = sums.readInt();
set(fs.verifyChecksum, DataChecksum.newCrc32(), bytesPerSum, 4);
} catch (IOException e) {
// mincing the message is terrible, but java throws permission
// exceptions as FNF because that's all the method signatures allow!
if (!(e instanceof FileNotFoundException) ||
e.getMessage().endsWith(" (Permission denied)")) {
LOG.warn("Problem opening checksum file: "+ file +
". Ignoring exception: " , e);
}
set(fs.verifyChecksum, null, 1, 0);
}
}
private long getChecksumFilePos( long dataPos ) {
return HEADER_LENGTH + 4*(dataPos/bytesPerSum);
}
@Override
protected long getChunkPosition( long dataPos ) {
return dataPos/bytesPerSum*bytesPerSum;
}
@Override
public int available() throws IOException {
return datas.available() + super.available();
}
@Override
public int read(long position, byte[] b, int off, int len)
throws IOException {
// parameter check
if ((off | len | (off + len) | (b.length - (off + len))) < 0) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return 0;
}
if( position<0 ) {
throw new IllegalArgumentException(
"Parameter position can not to be negative");
}
ChecksumFSInputChecker checker = new ChecksumFSInputChecker(fs, file);
checker.seek(position);
int nread = checker.read(b, off, len);
checker.close();
return nread;
}
@Override
public void close() throws IOException {
datas.close();
if( sums != null ) {
sums.close();
}
set(fs.verifyChecksum, null, 1, 0);
}
@Override
public boolean seekToNewSource(long targetPos) throws IOException {
long sumsPos = getChecksumFilePos(targetPos);
fs.reportChecksumFailure(file, datas, targetPos, sums, sumsPos);
boolean newDataSource = datas.seekToNewSource(targetPos);
return sums.seekToNewSource(sumsPos) || newDataSource;
}
@Override
protected int readChunk(long pos, byte[] buf, int offset, int len,
byte[] checksum) throws IOException {
boolean eof = false;
if (needChecksum()) {
assert checksum != null; // we have a checksum buffer
assert checksum.length % CHECKSUM_SIZE == 0; // it is sane length
assert len >= bytesPerSum; // we must read at least one chunk
final int checksumsToRead = Math.min(
len/bytesPerSum, // number of checksums based on len to read
checksum.length / CHECKSUM_SIZE); // size of checksum buffer
long checksumPos = getChecksumFilePos(pos);
if(checksumPos != sums.getPos()) {
sums.seek(checksumPos);
}
int sumLenRead = sums.read(checksum, 0, CHECKSUM_SIZE * checksumsToRead);
if (sumLenRead >= 0 && sumLenRead % CHECKSUM_SIZE != 0) {
throw new ChecksumException(
"Checksum file not a length multiple of checksum size " +
"in " + file + " at " + pos + " checksumpos: " + checksumPos +
" sumLenread: " + sumLenRead,
pos);
}
if (sumLenRead <= 0) { // we're at the end of the file
eof = true;
} else {
// Adjust amount of data to read based on how many checksum chunks we read
len = Math.min(len, bytesPerSum * (sumLenRead / CHECKSUM_SIZE));
}
}
if(pos != datas.getPos()) {
datas.seek(pos);
}
int nread = readFully(datas, buf, offset, len);
if (eof && nread > 0) {
throw new ChecksumException("Checksum error: "+file+" at "+pos, pos);
}
return nread;
}
}
private static class FSDataBoundedInputStream extends FSDataInputStream {
private FileSystem fs;
private Path file;
private long fileLen = -1L;
FSDataBoundedInputStream(FileSystem fs, Path file, InputStream in) {
super(in);
this.fs = fs;
this.file = file;
}
@Override
public boolean markSupported() {
return false;
}
/* Return the file length */
private long getFileLength() throws IOException {
if( fileLen==-1L ) {
fileLen = fs.getContentSummary(file).getLength();
}
return fileLen;
}
/**
* Skips over and discards n bytes of data from the
* input stream.
*
*The skip method skips over some smaller number of bytes
* when reaching end of file before n bytes have been skipped.
* The actual number of bytes skipped is returned. If n is
* negative, no bytes are skipped.
*
* @param n the number of bytes to be skipped.
* @return the actual number of bytes skipped.
* @exception IOException if an I/O error occurs.
* ChecksumException if the chunk to skip to is corrupted
*/
@Override
public synchronized long skip(long n) throws IOException {
long curPos = getPos();
long fileLength = getFileLength();
if( n+curPos > fileLength ) {
n = fileLength - curPos;
}
return super.skip(n);
}
/**
* Seek to the given position in the stream.
* The next read() will be from that position.
*
* This method does not allow seek past the end of the file.
* This produces IOException.
*
* @param pos the postion to seek to.
* @exception IOException if an I/O error occurs or seeks after EOF
* ChecksumException if the chunk to seek to is corrupted
*/
@Override
public synchronized void seek(long pos) throws IOException {
if (pos > getFileLength()) {
throw new EOFException("Cannot seek after EOF");
}
super.seek(pos);
}
}
/**
* Opens an FSDataInputStream at the indicated Path.
* @param f the file name to open
* @param bufferSize the size of the buffer to be used.
*/
@Override
public FSDataInputStream open(Path f, int bufferSize) throws IOException {
FileSystem fs;
InputStream in;
if (verifyChecksum) {
fs = this;
in = new ChecksumFSInputChecker(this, f, bufferSize);
} else {
fs = getRawFileSystem();
in = fs.open(f, bufferSize);
}
return new FSDataBoundedInputStream(fs, f, in);
}
@Override
public FSDataOutputStream append(Path f, int bufferSize,
Progressable progress) throws IOException {
throw new IOException("Not supported");
}
@Override
public boolean truncate(Path f, long newLength) throws IOException {
throw new IOException("Not supported");
}
/**
* Calculated the length of the checksum file in bytes.
* @param size the length of the data file in bytes
* @param bytesPerSum the number of bytes in a checksum block
* @return the number of bytes in the checksum file
*/
public static long getChecksumLength(long size, int bytesPerSum) {
//the checksum length is equal to size passed divided by bytesPerSum +
//bytes written in the beginning of the checksum file.
return ((size + bytesPerSum - 1) / bytesPerSum) * 4 +
CHECKSUM_VERSION.length + 4;
}
/** This class provides an output stream for a checksummed file.
* It generates checksums for data. */
private static class ChecksumFSOutputSummer extends FSOutputSummer {
private FSDataOutputStream datas;
private FSDataOutputStream sums;
private static final float CHKSUM_AS_FRACTION = 0.01f;
private boolean isClosed = false;
public ChecksumFSOutputSummer(ChecksumFileSystem fs,
Path file,
boolean overwrite,
int bufferSize,
short replication,
long blockSize,
Progressable progress,
FsPermission permission)
throws IOException {
super(DataChecksum.newDataChecksum(DataChecksum.Type.CRC32,
fs.getBytesPerSum()));
int bytesPerSum = fs.getBytesPerSum();
this.datas = fs.getRawFileSystem().create(file, permission, overwrite,
bufferSize, replication, blockSize,
progress);
int sumBufferSize = fs.getSumBufferSize(bytesPerSum, bufferSize);
this.sums = fs.getRawFileSystem().create(fs.getChecksumFile(file),
permission, true, sumBufferSize,
replication, blockSize, null);
sums.write(CHECKSUM_VERSION, 0, CHECKSUM_VERSION.length);
sums.writeInt(bytesPerSum);
}
@Override
public void close() throws IOException {
try {
flushBuffer();
sums.close();
datas.close();
} finally {
isClosed = true;
}
}
@Override
protected void writeChunk(byte[] b, int offset, int len, byte[] checksum,
int ckoff, int cklen)
throws IOException {
datas.write(b, offset, len);
sums.write(checksum, ckoff, cklen);
}
@Override
protected void checkClosed() throws IOException {
if (isClosed) {
throw new ClosedChannelException();
}
}
}
@Override
public FSDataOutputStream create(Path f, FsPermission permission,
boolean overwrite, int bufferSize, short replication, long blockSize,
Progressable progress) throws IOException {
return create(f, permission, overwrite, true, bufferSize,
replication, blockSize, progress);
}
private FSDataOutputStream create(Path f, FsPermission permission,
boolean overwrite, boolean createParent, int bufferSize,
short replication, long blockSize,
Progressable progress) throws IOException {
Path parent = f.getParent();
if (parent != null) {
if (!createParent && !exists(parent)) {
throw new FileNotFoundException("Parent directory doesn't exist: "
+ parent);
} else if (!mkdirs(parent)) {
throw new IOException("Mkdirs failed to create " + parent
+ " (exists=" + exists(parent) + ", cwd=" + getWorkingDirectory()
+ ")");
}
}
final FSDataOutputStream out;
if (writeChecksum) {
out = new FSDataOutputStream(
new ChecksumFSOutputSummer(this, f, overwrite, bufferSize, replication,
blockSize, progress, permission), null);
} else {
out = fs.create(f, permission, overwrite, bufferSize, replication,
blockSize, progress);
// remove the checksum file since we aren't writing one
Path checkFile = getChecksumFile(f);
if (fs.exists(checkFile)) {
fs.delete(checkFile, true);
}
}
return out;
}
@Override
public FSDataOutputStream createNonRecursive(Path f, FsPermission permission,
boolean overwrite, int bufferSize, short replication, long blockSize,
Progressable progress) throws IOException {
return create(f, permission, overwrite, false, bufferSize, replication,
blockSize, progress);
}
abstract class FsOperation {
boolean run(Path p) throws IOException {
boolean status = apply(p);
if (status) {
Path checkFile = getChecksumFile(p);
if (fs.exists(checkFile)) {
apply(checkFile);
}
}
return status;
}
abstract boolean apply(Path p) throws IOException;
}
@Override
public void setPermission(Path src, final FsPermission permission)
throws IOException {
new FsOperation(){
@Override
boolean apply(Path p) throws IOException {
fs.setPermission(p, permission);
return true;
}
}.run(src);
}
@Override
public void setOwner(Path src, final String username, final String groupname)
throws IOException {
new FsOperation(){
@Override
boolean apply(Path p) throws IOException {
fs.setOwner(p, username, groupname);
return true;
}
}.run(src);
}
@Override
public void setAcl(Path src, final List aclSpec)
throws IOException {
new FsOperation(){
@Override
boolean apply(Path p) throws IOException {
fs.setAcl(p, aclSpec);
return true;
}
}.run(src);
}
@Override
public void modifyAclEntries(Path src, final List aclSpec)
throws IOException {
new FsOperation(){
@Override
boolean apply(Path p) throws IOException {
fs.modifyAclEntries(p, aclSpec);
return true;
}
}.run(src);
}
@Override
public void removeAcl(Path src) throws IOException {
new FsOperation(){
@Override
boolean apply(Path p) throws IOException {
fs.removeAcl(p);
return true;
}
}.run(src);
}
@Override
public void removeAclEntries(Path src, final List aclSpec)
throws IOException {
new FsOperation(){
@Override
boolean apply(Path p) throws IOException {
fs.removeAclEntries(p, aclSpec);
return true;
}
}.run(src);
}
@Override
public void removeDefaultAcl(Path src) throws IOException {
new FsOperation(){
@Override
boolean apply(Path p) throws IOException {
fs.removeDefaultAcl(p);
return true;
}
}.run(src);
}
/**
* Set replication for an existing file.
* Implement the abstract setReplication of FileSystem
* @param src file name
* @param replication new replication
* @throws IOException
* @return true if successful;
* false if file does not exist or is a directory
*/
@Override
public boolean setReplication(Path src, final short replication)
throws IOException {
return new FsOperation(){
@Override
boolean apply(Path p) throws IOException {
return fs.setReplication(p, replication);
}
}.run(src);
}
/**
* Rename files/dirs
*/
@Override
public boolean rename(Path src, Path dst) throws IOException {
if (fs.isDirectory(src)) {
return fs.rename(src, dst);
} else {
if (fs.isDirectory(dst)) {
dst = new Path(dst, src.getName());
}
boolean value = fs.rename(src, dst);
if (!value)
return false;
Path srcCheckFile = getChecksumFile(src);
Path dstCheckFile = getChecksumFile(dst);
if (fs.exists(srcCheckFile)) { //try to rename checksum
value = fs.rename(srcCheckFile, dstCheckFile);
} else if (fs.exists(dstCheckFile)) {
// no src checksum, so remove dst checksum
value = fs.delete(dstCheckFile, true);
}
return value;
}
}
/**
* Implement the delete(Path, boolean) in checksum
* file system.
*/
@Override
public boolean delete(Path f, boolean recursive) throws IOException{
FileStatus fstatus = null;
try {
fstatus = fs.getFileStatus(f);
} catch(FileNotFoundException e) {
return false;
}
if (fstatus.isDirectory()) {
//this works since the crcs are in the same
//directories and the files. so we just delete
//everything in the underlying filesystem
return fs.delete(f, recursive);
} else {
Path checkFile = getChecksumFile(f);
if (fs.exists(checkFile)) {
fs.delete(checkFile, true);
}
return fs.delete(f, true);
}
}
final private static PathFilter DEFAULT_FILTER = new PathFilter() {
@Override
public boolean accept(Path file) {
return !isChecksumFile(file);
}
};
/**
* List the statuses of the files/directories in the given path if the path is
* a directory.
*
* @param f
* given path
* @return the statuses of the files/directories in the given path
* @throws IOException
*/
@Override
public FileStatus[] listStatus(Path f) throws IOException {
return fs.listStatus(f, DEFAULT_FILTER);
}
/**
* List the statuses of the files/directories in the given path if the path is
* a directory.
*
* @param f
* given path
* @return the statuses of the files/directories in the given patch
* @throws IOException
*/
@Override
public RemoteIterator listLocatedStatus(Path f)
throws IOException {
return fs.listLocatedStatus(f, DEFAULT_FILTER);
}
@Override
public boolean mkdirs(Path f) throws IOException {
return fs.mkdirs(f);
}
@Override
public void copyFromLocalFile(boolean delSrc, Path src, Path dst)
throws IOException {
Configuration conf = getConf();
FileUtil.copy(getLocal(conf), src, this, dst, delSrc, conf);
}
/**
* The src file is under FS, and the dst is on the local disk.
* Copy it from FS control to the local dst name.
*/
@Override
public void copyToLocalFile(boolean delSrc, Path src, Path dst)
throws IOException {
Configuration conf = getConf();
FileUtil.copy(this, src, getLocal(conf), dst, delSrc, conf);
}
/**
* The src file is under FS, and the dst is on the local disk.
* Copy it from FS control to the local dst name.
* If src and dst are directories, the copyCrc parameter
* determines whether to copy CRC files.
*/
public void copyToLocalFile(Path src, Path dst, boolean copyCrc)
throws IOException {
if (!fs.isDirectory(src)) { // source is a file
fs.copyToLocalFile(src, dst);
FileSystem localFs = getLocal(getConf()).getRawFileSystem();
if (localFs.isDirectory(dst)) {
dst = new Path(dst, src.getName());
}
dst = getChecksumFile(dst);
if (localFs.exists(dst)) { //remove old local checksum file
localFs.delete(dst, true);
}
Path checksumFile = getChecksumFile(src);
if (copyCrc && fs.exists(checksumFile)) { //copy checksum file
fs.copyToLocalFile(checksumFile, dst);
}
} else {
FileStatus[] srcs = listStatus(src);
for (FileStatus srcFile : srcs) {
copyToLocalFile(srcFile.getPath(),
new Path(dst, srcFile.getPath().getName()), copyCrc);
}
}
}
@Override
public Path startLocalOutput(Path fsOutputFile, Path tmpLocalFile)
throws IOException {
return tmpLocalFile;
}
@Override
public void completeLocalOutput(Path fsOutputFile, Path tmpLocalFile)
throws IOException {
moveFromLocalFile(tmpLocalFile, fsOutputFile);
}
/**
* Report a checksum error to the file system.
* @param f the file name containing the error
* @param in the stream open on the file
* @param inPos the position of the beginning of the bad data in the file
* @param sums the stream open on the checksum file
* @param sumsPos the position of the beginning of the bad data in the checksum file
* @return if retry is neccessary
*/
public boolean reportChecksumFailure(Path f, FSDataInputStream in,
long inPos, FSDataInputStream sums, long sumsPos) {
return false;
}
}