/**
* Copy specified file into a temporary file. Then rename the temporary file to the original name.
* This will cause any hardlinks to the original file to be removed. The temporary files are
* created in the same directory. The temporary files will be recovered (especially on Windows) on
* datanode restart.
*/
private void unlinkFile(File file, Block b) throws IOException {
File tmpFile = DatanodeUtil.createTmpFile(b, DatanodeUtil.getUnlinkTmpFile(file));
try {
FileInputStream in = new FileInputStream(file);
try {
FileOutputStream out = new FileOutputStream(tmpFile);
try {
IOUtils.copyBytes(in, out, 16 * 1024);
} finally {
out.close();
}
} finally {
in.close();
}
if (file.length() != tmpFile.length()) {
throw new IOException(
"Copy of file "
+ file
+ " size "
+ file.length()
+ " into file "
+ tmpFile
+ " resulted in a size of "
+ tmpFile.length());
}
FileUtil.replaceFile(tmpFile, file);
} catch (IOException e) {
boolean done = tmpFile.delete();
if (!done) {
DataNode.LOG.info("detachFile failed to delete temporary file " + tmpFile);
}
throw e;
}
}
/**
* Remove a hard link by copying the block to a temporary place and then moving it back
*
* @param numLinks number of hard links
* @return true if copy is successful; false if it is already detached or no need to be detached
* @throws IOException if there is any copy error
*/
public boolean unlinkBlock(int numLinks) throws IOException {
if (isUnlinked()) {
return false;
}
File file = getBlockFile();
if (file == null || getVolume() == null) {
throw new IOException("detachBlock:Block not found. " + this);
}
File meta = getMetaFile();
if (HardLink.getLinkCount(file) > numLinks) {
DataNode.LOG.info("CopyOnWrite for block " + this);
unlinkFile(file, this);
}
if (HardLink.getLinkCount(meta) > numLinks) {
unlinkFile(meta, this);
}
setUnlinked();
return true;
}
/**
* Register the FSDataset MBean using the name
* "hadoop:service=DataNode,name=FSDatasetState-<storageid>"
*/
void registerMBean(final String storageId) {
// We wrap to bypass standard mbean naming convetion.
// This wraping can be removed in java 6 as it is more flexible in
// package naming for mbeans and their impl.
StandardMBean bean;
String storageName;
if (storageId == null || storageId.equals("")) { // Temp fix for the
// uninitialized storage
storageName = "UndefinedStorageId" + rand.nextInt();
} else {
storageName = storageId;
}
try {
bean = new StandardMBean(this, FSDatasetMBean.class);
mbeanName = MBeanUtil.registerMBean("DataNode", "FSDatasetState-" + storageName, bean);
} catch (NotCompliantMBeanException e) {
e.printStackTrace();
}
DataNode.LOG.info("Registered FSDatasetStatusMBean");
}
/**
* Start writing to a block file If isRecovery is true and the block pre-exists, then we kill all
* volumeMap.put(b, v); volumeMap.put(b, v); other threads that might be writing to this block,
* and then reopen the file.
*/
public BlockWriteStreams writeToBlock(Block b, boolean isRecovery) throws IOException {
//
// Make sure the block isn't a valid one - we're still creating it!
//
if (isValidBlock(b)) {
if (!isRecovery) {
throw new BlockAlreadyExistsException(
"Block " + b + " is valid, and cannot be written to.");
}
// If the block was successfully finalized because all packets
// were successfully processed at the Datanode but the ack for
// some of the packets were not received by the client. The client
// re-opens the connection and retries sending those packets.
// The other reason is that an "append" is occurring to this block.
detachBlock(b, 1);
}
long blockSize = b.getNumBytes();
//
// Serialize access to /tmp, and check if file already there.
//
File f = null;
List<Thread> threads = null;
synchronized (this) {
//
// Is it already in the create process?
//
ActiveFile activeFile = ongoingCreates.get(b);
if (activeFile != null) {
f = activeFile.file;
threads = activeFile.threads;
if (!isRecovery) {
throw new BlockAlreadyExistsException(
"Block "
+ b
+ " has already been started (though not completed), and thus cannot be created.");
} else {
for (Thread thread : threads) {
thread.interrupt();
}
}
ongoingCreates.remove(b);
}
FSVolume v = null;
if (!isRecovery) {
v = volumes.getNextVolume(blockSize);
// create temporary file to hold block in the designated volume
f = createTmpFile(v, b);
volumeMap.put(b, new DatanodeBlockInfo(v));
} else if (f != null) {
DataNode.LOG.info("Reopen already-open Block for append " + b);
// create or reuse temporary file to hold block in the
// designated volume
v = volumeMap.get(b).getVolume();
volumeMap.put(b, new DatanodeBlockInfo(v));
} else {
// reopening block for appending to it.
DataNode.LOG.info("Reopen Block for append " + b);
v = volumeMap.get(b).getVolume();
f = createTmpFile(v, b);
File blkfile = getBlockFile(b);
File oldmeta = getMetaFile(b);
File newmeta = getMetaFile(f, b);
// rename meta file to tmp directory
DataNode.LOG.debug("Renaming " + oldmeta + " to " + newmeta);
if (!oldmeta.renameTo(newmeta)) {
throw new IOException(
"Block "
+ b
+ " reopen failed. "
+ " Unable to move meta file "
+ oldmeta
+ " to tmp dir "
+ newmeta);
}
// rename block file to tmp directory
DataNode.LOG.debug("Renaming " + blkfile + " to " + f);
if (!blkfile.renameTo(f)) {
if (!f.delete()) {
throw new IOException(
"Block " + b + " reopen failed. " + " Unable to remove file " + f);
}
if (!blkfile.renameTo(f)) {
throw new IOException(
"Block "
+ b
+ " reopen failed. "
+ " Unable to move block file "
+ blkfile
+ " to tmp dir "
+ f);
}
}
volumeMap.put(b, new DatanodeBlockInfo(v));
}
if (f == null) {
DataNode.LOG.warn("Block " + b + " reopen failed " + " Unable to locate tmp file.");
throw new IOException("Block " + b + " reopen failed " + " Unable to locate tmp file.");
}
ongoingCreates.put(b, new ActiveFile(f, threads));
}
try {
if (threads != null) {
for (Thread thread : threads) {
thread.join();
}
}
} catch (InterruptedException e) {
throw new IOException("Recovery waiting for thread interrupted.");
}
//
// Finally, allow a writer to the block file
// REMIND - mjc - make this a filter stream that enforces a max
// block size, so clients can't go crazy
//
File metafile = getMetaFile(f, b);
DataNode.LOG.debug("writeTo blockfile is " + f + " of size " + f.length());
DataNode.LOG.debug("writeTo metafile is " + metafile + " of size " + metafile.length());
return createBlockWriteStreams(f, metafile);
}
/**
* We're informed that a block is no longer valid. We could lazily garbage-collect the block, but
* why bother? just get rid of it.
*/
public void invalidate(Block invalidBlks[]) throws IOException {
boolean error = false;
for (int i = 0; i < invalidBlks.length; i++) {
File f = null;
FSVolume v;
synchronized (this) {
f = getFile(invalidBlks[i]);
DatanodeBlockInfo dinfo = volumeMap.get(invalidBlks[i]);
if (dinfo == null) {
DataNode.LOG.warn(
"Unexpected error trying to delete block "
+ invalidBlks[i]
+ ". BlockInfo not found in volumeMap.");
error = true;
continue;
}
v = dinfo.getVolume();
if (f == null) {
DataNode.LOG.warn(
"Unexpected error trying to delete block "
+ invalidBlks[i]
+ ". Block not found in blockMap."
+ ((v == null) ? " " : " Block found in volumeMap."));
error = true;
continue;
}
if (v == null) {
DataNode.LOG.warn(
"Unexpected error trying to delete block "
+ invalidBlks[i]
+ ". No volume for this block."
+ " Block found in blockMap. "
+ f
+ ".");
error = true;
continue;
}
File parent = f.getParentFile();
if (parent == null) {
DataNode.LOG.warn(
"Unexpected error trying to delete block "
+ invalidBlks[i]
+ ". Parent not found for file "
+ f
+ ".");
error = true;
continue;
}
v.clearPath(parent);
volumeMap.remove(invalidBlks[i]);
}
File metaFile = getMetaFile(f, invalidBlks[i]);
long blockSize = f.length() + metaFile.length();
if (!f.delete() || (!metaFile.delete() && metaFile.exists())) {
DataNode.LOG.warn(
"Unexpected error trying to delete block " + invalidBlks[i] + " at file " + f);
error = true;
continue;
}
v.decDfsUsed(blockSize);
DataNode.LOG.info("Deleting block " + invalidBlks[i] + " file " + f);
if (f.exists()) {
//
// This is a temporary check especially for hadoop-1220.
// This will go away in the future.
//
DataNode.LOG.info("File " + f + " was deleted but still exists!");
}
}
if (error) {
throw new IOException("Error in deleting blocks.");
}
}
