/** Turn the block identifier into a filename. */
public synchronized File getFile(Block b) {
DatanodeBlockInfo info = volumeMap.get(b);
if (info != null) {
return info.getFile();
}
return null;
}
/**
* Make a copy of the block if this block is linked to an existing snapshot. This ensures that
* modifying this block does not modify data in any existing snapshots.
*
* @param block Block
* @param numLinks Detach if the number of links exceed this value
* @throws IOException
* @return - true if the specified block was detached
*/
public boolean detachBlock(Block block, int numLinks) throws IOException {
DatanodeBlockInfo info = null;
synchronized (this) {
info = volumeMap.get(block);
}
return info.detachBlock(block, numLinks);
}
synchronized File createTmpFile(FSVolume vol, Block blk) throws IOException {
if (vol == null) {
vol = volumeMap.get(blk).getVolume();
if (vol == null) {
throw new IOException("Could not find volume for block " + blk);
}
}
return vol.createTmpFile(blk);
}
/** Complete the block write! */
public synchronized void finalizeBlock(Block b) throws IOException {
ActiveFile activeFile = ongoingCreates.get(b);
if (activeFile == null) {
throw new IOException("Block " + b + " is already finalized.");
}
File f = activeFile.file;
if (f == null || !f.exists()) {
throw new IOException("No temporary file " + f + " for block " + b);
}
FSVolume v = volumeMap.get(b).getVolume();
if (v == null) {
throw new IOException("No volume for temporary file " + f + " for block " + b);
}
File dest = null;
dest = v.addBlock(b, f);
volumeMap.put(b, new DatanodeBlockInfo(v, dest));
ongoingCreates.remove(b);
}
public void map(LongWritable key, Text value, Context context)
throws IOException, InterruptedException {
Configuration c = context.getConfiguration();
String s = value.toString();
String input[] = s.split(",");
Text outputkey = new Text();
Text outputvalue = new Text();
double result = 0.0;
/* multiplies matrix and vector entry with matching column value */
result = (Double.parseDouble(input[2])) * (vector.get(Long.parseLong(input[1])));
outputkey.set(input[0]);
outputvalue.set(Double.toString(result));
context.write(outputkey, outputvalue);
}
/** {@inheritDoc} */
public void validateBlockMetadata(Block b) throws IOException {
DatanodeBlockInfo info = volumeMap.get(b);
if (info == null) {
throw new IOException("Block " + b + " does not exist in volumeMap.");
}
FSVolume v = info.getVolume();
File tmp = v.getTmpFile(b);
File f = getFile(b);
if (f == null) {
f = tmp;
}
if (f == null) {
throw new IOException("Block " + b + " does not exist on disk.");
}
if (!f.exists()) {
throw new IOException("Block " + b + " block file " + f + " does not exist on disk.");
}
if (b.getNumBytes() != f.length()) {
throw new IOException(
"Block "
+ b
+ " length is "
+ b.getNumBytes()
+ " does not match block file length "
+ f.length());
}
File meta = getMetaFile(f, b);
if (meta == null) {
throw new IOException("Block " + b + " metafile does not exist.");
}
if (!meta.exists()) {
throw new IOException("Block " + b + " metafile " + meta + " does not exist on disk.");
}
if (meta.length() == 0) {
throw new IOException("Block " + b + " metafile " + meta + " is empty.");
}
long stamp = parseGenerationStamp(f, meta);
if (stamp != b.getGenerationStamp()) {
throw new IOException(
"Block "
+ b
+ " genstamp is "
+ b.getGenerationStamp()
+ " does not match meta file stamp "
+ stamp);
}
}
/** Returns handles to the block file and its metadata file */
public synchronized BlockInputStreams getTmpInputStreams(Block b, long blkOffset, long ckoff)
throws IOException {
DatanodeBlockInfo info = volumeMap.get(b);
if (info == null) {
throw new IOException("Block " + b + " does not exist in volumeMap.");
}
FSVolume v = info.getVolume();
File blockFile = v.getTmpFile(b);
RandomAccessFile blockInFile = new RandomAccessFile(blockFile, "r");
if (blkOffset > 0) {
blockInFile.seek(blkOffset);
}
File metaFile = getMetaFile(blockFile, b);
RandomAccessFile metaInFile = new RandomAccessFile(metaFile, "r");
if (ckoff > 0) {
metaInFile.seek(ckoff);
}
return new BlockInputStreams(
new FileInputStream(blockInFile.getFD()), new FileInputStream(metaInFile.getFD()));
}
/** Sets the offset in the block to which the the next write will write data to. */
public void setChannelPosition(Block b, BlockWriteStreams streams, long dataOffset, long ckOffset)
throws IOException {
long size = 0;
synchronized (this) {
FSVolume vol = volumeMap.get(b).getVolume();
size = vol.getTmpFile(b).length();
}
if (size < dataOffset) {
String msg =
"Trying to change block file offset of block "
+ b
+ " to "
+ dataOffset
+ " but actual size of file is "
+ size;
throw new IOException(msg);
}
FileOutputStream file = (FileOutputStream) streams.dataOut;
file.getChannel().position(dataOffset);
file = (FileOutputStream) streams.checksumOut;
file.getChannel().position(ckOffset);
}
public void reduce(
IntWritable key,
Iterator<Text> values,
OutputCollector<IntWritable, Text> output,
Reporter reporter)
throws IOException {
HashMap<String, Integer> countries_map = new HashMap<String, Integer>();
ArrayList<Integer> counties = new ArrayList<>();
String cp = new String();
while (values.hasNext()) {
cp = values.next().toString();
if (countries_map.containsKey(cp)) {
countries_map.put(cp, countries_map.get(cp) + 1);
} else {
countries_map.put(cp, 1);
}
}
for (java.util.Map.Entry<String, Integer> entry : countries_map.entrySet()) {
counties.add(entry.getValue());
}
output.collect(
key,
new Text(
""
+ countries_map.entrySet().size()
+ " "
+ Collections.min(counties)
+ " "
+ median(counties)
+ " "
+ Collections.max(counties)
+ " "
+ mean(counties)
+ " "
+ standard_deviation(counties)));
}
/**
* 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);
}
/**
* Try to update an old block to a new block. If there are ongoing create threads running for the
* old block, the threads will be returned without updating the block.
*
* @return ongoing create threads if there is any. Otherwise, return null.
*/
private synchronized List<Thread> tryUpdateBlock(Block oldblock, Block newblock)
throws IOException {
// check ongoing create threads
final ActiveFile activefile = ongoingCreates.get(oldblock);
if (activefile != null && !activefile.threads.isEmpty()) {
// remove dead threads
for (Iterator<Thread> i = activefile.threads.iterator(); i.hasNext(); ) {
final Thread t = i.next();
if (!t.isAlive()) {
i.remove();
}
}
// return living threads
if (!activefile.threads.isEmpty()) {
return new ArrayList<Thread>(activefile.threads);
}
}
// No ongoing create threads is alive. Update block.
File blockFile = findBlockFile(oldblock.getBlockId());
if (blockFile == null) {
throw new IOException("Block " + oldblock + " does not exist.");
}
File oldMetaFile = findMetaFile(blockFile);
long oldgs = parseGenerationStamp(blockFile, oldMetaFile);
// rename meta file to a tmp file
File tmpMetaFile =
new File(
oldMetaFile.getParent(),
oldMetaFile.getName() + "_tmp" + newblock.getGenerationStamp());
if (!oldMetaFile.renameTo(tmpMetaFile)) {
throw new IOException("Cannot rename block meta file to " + tmpMetaFile);
}
// update generation stamp
if (oldgs > newblock.getGenerationStamp()) {
throw new IOException(
"Cannot update block (id="
+ newblock.getBlockId()
+ ") generation stamp from "
+ oldgs
+ " to "
+ newblock.getGenerationStamp());
}
// update length
if (newblock.getNumBytes() > oldblock.getNumBytes()) {
throw new IOException(
"Cannot update block file (="
+ blockFile
+ ") length from "
+ oldblock.getNumBytes()
+ " to "
+ newblock.getNumBytes());
}
if (newblock.getNumBytes() < oldblock.getNumBytes()) {
truncateBlock(blockFile, tmpMetaFile, oldblock.getNumBytes(), newblock.getNumBytes());
}
// rename the tmp file to the new meta file (with new generation stamp)
File newMetaFile = getMetaFile(blockFile, newblock);
if (!tmpMetaFile.renameTo(newMetaFile)) {
throw new IOException("Cannot rename tmp meta file to " + newMetaFile);
}
updateBlockMap(ongoingCreates, oldblock, newblock);
updateBlockMap(volumeMap, oldblock, newblock);
// paranoia! verify that the contents of the stored block
// matches the block file on disk.
validateBlockMetadata(newblock);
return null;
}
/**
* 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.");
}
}