/**
* 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.namenode;
import java.io.IOException;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.SortedSet;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.Options;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
import static org.apache.hadoop.util.ExitUtil.terminate;
import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.NamenodeRole;
import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory;
import static org.apache.hadoop.hdfs.server.common.Util.now;
import org.apache.hadoop.hdfs.server.namenode.NNStorage.NameNodeDirType;
import org.apache.hadoop.hdfs.server.namenode.metrics.NameNodeMetrics;
import org.apache.hadoop.hdfs.server.protocol.NamenodeRegistration;
import org.apache.hadoop.hdfs.server.protocol.RemoteEditLogManifest;
import org.apache.hadoop.hdfs.server.protocol.RemoteEditLog;
import org.apache.hadoop.security.token.delegation.DelegationKey;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableListMultimap;
import com.google.common.collect.Lists;
import com.google.common.collect.Multimaps;
import com.google.common.collect.Sets;
import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.*;
/**
* FSEditLog maintains a log of the namespace modifications.
*
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class FSEditLog {
static final String NO_JOURNAL_STREAMS_WARNING = "!!! WARNING !!!" +
" File system changes are not persistent. No journal streams.";
static final Log LOG = LogFactory.getLog(FSEditLog.class);
/**
* State machine for edit log.
* The log starts in UNITIALIZED state upon construction. Once it's
* initialized, it is usually in IN_SEGMENT state, indicating that edits
* may be written. In the middle of a roll, or while saving the namespace,
* it briefly enters the BETWEEN_LOG_SEGMENTS state, indicating that the
* previous segment has been closed, but the new one has not yet been opened.
*/
private enum State {
UNINITIALIZED,
BETWEEN_LOG_SEGMENTS,
IN_SEGMENT,
CLOSED;
}
private State state = State.UNINITIALIZED;
private List<JournalAndStream> journals = Lists.newArrayList();
// a monotonically increasing counter that represents transactionIds.
private long txid = 0;
// stores the last synced transactionId.
private long synctxid = 0;
// the first txid of the log that's currently open for writing.
// If this value is N, we are currently writing to edits_inprogress_N
private long curSegmentTxId = HdfsConstants.INVALID_TXID;
// the time of printing the statistics to the log file.
private long lastPrintTime;
// is a sync currently running?
private volatile boolean isSyncRunning;
// is an automatic sync scheduled?
private volatile boolean isAutoSyncScheduled = false;
// these are statistics counters.
private long numTransactions; // number of transactions
private long numTransactionsBatchedInSync;
private long totalTimeTransactions; // total time for all transactions
private NameNodeMetrics metrics;
private NNStorage storage;
private static class TransactionId {
public long txid;
TransactionId(long value) {
this.txid = value;
}
}
// stores the most current transactionId of this thread.
private static final ThreadLocal<TransactionId> myTransactionId = new ThreadLocal<TransactionId>() {
protected synchronized TransactionId initialValue() {
return new TransactionId(Long.MAX_VALUE);
}
};
FSEditLog(NNStorage storage) {
isSyncRunning = false;
this.storage = storage;
metrics = NameNode.getNameNodeMetrics();
lastPrintTime = now();
for (StorageDirectory sd : storage.dirIterable(NameNodeDirType.EDITS)) {
journals.add(new JournalAndStream(new FileJournalManager(sd)));
}
if (journals.isEmpty()) {
LOG.error("No edits directories configured!");
}
state = State.BETWEEN_LOG_SEGMENTS;
}
/**
* Initialize the output stream for logging, opening the first
* log segment.
*/
synchronized void open() throws IOException {
Preconditions.checkState(state == State.BETWEEN_LOG_SEGMENTS);
startLogSegment(getLastWrittenTxId() + 1, true);
assert state == State.IN_SEGMENT : "Bad state: " + state;
}
synchronized boolean isOpen() {
return state == State.IN_SEGMENT;
}
/**
* Shutdown the file store.
*/
synchronized void close() {
if (state == State.CLOSED) {
LOG.debug("Closing log when already closed");
return;
}
if (state == State.IN_SEGMENT) {
assert !journals.isEmpty();
waitForSyncToFinish();
endCurrentLogSegment(true);
}
state = State.CLOSED;
}
/**
* Write an operation to the edit log. Do not sync to persistent
* store yet.
*/
void logEdit(final FSEditLogOp op) {
synchronized (this) {
assert state != State.CLOSED;
// wait if an automatic sync is scheduled
waitIfAutoSyncScheduled();
if (journals.isEmpty()) {
throw new java.lang.IllegalStateException(NO_JOURNAL_STREAMS_WARNING);
}
long start = beginTransaction();
op.setTransactionId(txid);
mapJournalsAndReportErrors(new JournalClosure() {
@Override
public void apply(JournalAndStream jas) throws IOException {
if (!jas.isActive()) return;
jas.stream.write(op);
}
}, "logging edit");
endTransaction(start);
// check if it is time to schedule an automatic sync
if (!shouldForceSync()) {
return;
}
isAutoSyncScheduled = true;
}
// sync buffered edit log entries to persistent store
logSync();
}
/**
* Wait if an automatic sync is scheduled
* @throws InterruptedException
*/
synchronized void waitIfAutoSyncScheduled() {
try {
while (isAutoSyncScheduled) {
this.wait(1000);
}
} catch (InterruptedException e) {
}
}
/**
* Signal that an automatic sync scheduling is done if it is scheduled
*/
synchronized void doneWithAutoSyncScheduling() {
if (isAutoSyncScheduled) {
isAutoSyncScheduled = false;
notifyAll();
}
}
/**
* Check if should automatically sync buffered edits to
* persistent store
*
* @return true if any of the edit stream says that it should sync
*/
private boolean shouldForceSync() {
for (JournalAndStream jas : journals) {
if (!jas.isActive()) continue;
if (jas.getCurrentStream().shouldForceSync()) {
return true;
}
}
return false;
}
private long beginTransaction() {
assert Thread.holdsLock(this);
// get a new transactionId
txid++;
//
// record the transactionId when new data was written to the edits log
//
TransactionId id = myTransactionId.get();
id.txid = txid;
return now();
}
private void endTransaction(long start) {
assert Thread.holdsLock(this);
// update statistics
long end = now();
numTransactions++;
totalTimeTransactions += (end-start);
if (metrics != null) // Metrics is non-null only when used inside name node
metrics.addTransaction(end-start);
}
/**
* Return the transaction ID of the last transaction written to the log.
*/
synchronized long getLastWrittenTxId() {
return txid;
}
/**
* @return the first transaction ID in the current log segment
*/
synchronized long getCurSegmentTxId() {
Preconditions.checkState(state == State.IN_SEGMENT,
"Bad state: %s", state);
return curSegmentTxId;
}
/**
* Set the transaction ID to use for the next transaction written.
*/
synchronized void setNextTxId(long nextTxId) {
Preconditions.checkArgument(synctxid <= txid &&
nextTxId >= txid,
"May not decrease txid." +
" synctxid=%s txid=%s nextTxId=%s",
synctxid, txid, nextTxId);
txid = nextTxId - 1;
}
/**
* Blocks until all ongoing edits have been synced to disk.
* This differs from logSync in that it waits for edits that have been
* written by other threads, not just edits from the calling thread.
*
* NOTE: this should be done while holding the FSNamesystem lock, or
* else more operations can start writing while this is in progress.
*/
void logSyncAll() throws IOException {
// Record the most recent transaction ID as our own id
synchronized (this) {
TransactionId id = myTransactionId.get();
id.txid = txid;
}
// Then make sure we're synced up to this point
logSync();
}
/**
* Sync all modifications done by this thread.
*
* The internal concurrency design of this class is as follows:
* - Log items are written synchronized into an in-memory buffer,
* and each assigned a transaction ID.
* - When a thread (client) would like to sync all of its edits, logSync()
* uses a ThreadLocal transaction ID to determine what edit number must
* be synced to.
* - The isSyncRunning volatile boolean tracks whether a sync is currently
* under progress.
*
* The data is double-buffered within each edit log implementation so that
* in-memory writing can occur in parallel with the on-disk writing.
*
* Each sync occurs in three steps:
* 1. synchronized, it swaps the double buffer and sets the isSyncRunning
* flag.
* 2. unsynchronized, it flushes the data to storage
* 3. synchronized, it resets the flag and notifies anyone waiting on the
* sync.
*
* The lack of synchronization on step 2 allows other threads to continue
* to write into the memory buffer while the sync is in progress.
* Because this step is unsynchronized, actions that need to avoid
* concurrency with sync() should be synchronized and also call
* waitForSyncToFinish() before assuming they are running alone.
*/
public void logSync() {
long syncStart = 0;
// Fetch the transactionId of this thread.
long mytxid = myTransactionId.get().txid;
List<JournalAndStream> candidateJournals =
Lists.newArrayListWithCapacity(journals.size());
List<JournalAndStream> badJournals = Lists.newArrayList();
boolean sync = false;
try {
synchronized (this) {
try {
printStatistics(false);
// if somebody is already syncing, then wait
while (mytxid > synctxid && isSyncRunning) {
try {
wait(1000);
} catch (InterruptedException ie) {
}
}
//
// If this transaction was already flushed, then nothing to do
//
if (mytxid <= synctxid) {
numTransactionsBatchedInSync++;
if (metrics != null) // Metrics is non-null only when used inside name node
metrics.incrTransactionsBatchedInSync();
return;
}
// now, this thread will do the sync
syncStart = txid;
isSyncRunning = true;
sync = true;
// swap buffers
assert !journals.isEmpty() : "no editlog streams";
for (JournalAndStream jas : journals) {
if (!jas.isActive()) continue;
try {
jas.getCurrentStream().setReadyToFlush();
candidateJournals.add(jas);
} catch (IOException ie) {
LOG.error("Unable to get ready to flush.", ie);
badJournals.add(jas);
}
}
} finally {
// Prevent RuntimeException from blocking other log edit write
doneWithAutoSyncScheduling();
}
}
// do the sync
long start = now();
for (JournalAndStream jas : candidateJournals) {
if (!jas.isActive()) continue;
try {
jas.getCurrentStream().flush();
} catch (IOException ie) {
LOG.error("Unable to sync edit log.", ie);
//
// remember the streams that encountered an error.
//
badJournals.add(jas);
}
}
long elapsed = now() - start;
disableAndReportErrorOnJournals(badJournals);
if (metrics != null) { // Metrics non-null only when used inside name node
metrics.addSync(elapsed);
}
} finally {
// Prevent RuntimeException from blocking other log edit sync
synchronized (this) {
if (sync) {
try {
if (badJournals.size() >= journals.size() ||
candidateJournals.isEmpty()) {
final String msg =
"Could not sync enough journals to persistent storage. "
+ "Unsynced transactions: " + (txid - synctxid);
LOG.fatal(msg, new Exception());
terminate(1, msg);
}
} finally {
synctxid = syncStart;
// NB: do that if finally block because even if #terminate(2) called above, we must unlock the waiting threads:
isSyncRunning = false;
}
}
this.notifyAll();
}
}
}
//
// print statistics every 1 minute.
//
private void printStatistics(boolean force) {
long now = now();
if (lastPrintTime + 60000 > now && !force) {
return;
}
if (journals.isEmpty()) {
return;
}
lastPrintTime = now;
StringBuilder buf = new StringBuilder();
buf.append("Number of transactions: ");
buf.append(numTransactions);
buf.append(" Total time for transactions(ms): ");
buf.append(totalTimeTransactions);
buf.append("Number of transactions batched in Syncs: ");
buf.append(numTransactionsBatchedInSync);
buf.append(" Number of syncs: ");
for (JournalAndStream jas : journals) {
if (!jas.isActive()) continue;
buf.append(jas.getCurrentStream().getNumSync());
break;
}
buf.append(" SyncTimes(ms): ");
for (JournalAndStream jas : journals) {
if (!jas.isActive()) continue;
EditLogOutputStream eStream = jas.getCurrentStream();
buf.append(eStream.getTotalSyncTime());
buf.append(" ");
}
LOG.info(buf);
}
/**
* Add open lease record to edit log.
* Records the block locations of the last block.
*/
public void logOpenFile(String path, INodeFileUnderConstruction newNode) {
AddOp op = AddOp.getInstance()
.setPath(path)
.setReplication(newNode.getReplication())
.setModificationTime(newNode.getModificationTime())
.setAccessTime(newNode.getAccessTime())
.setBlockSize(newNode.getPreferredBlockSize())
.setBlocks(newNode.getBlocks())
.setPermissionStatus(newNode.getPermissionStatus())
.setClientName(newNode.getClientName())
.setClientMachine(newNode.getClientMachine());
logEdit(op);
}
/**
* Add close lease record to edit log.
*/
public void logCloseFile(String path, INodeFile newNode) {
CloseOp op = CloseOp.getInstance()
.setPath(path)
.setReplication(newNode.getReplication())
.setModificationTime(newNode.getModificationTime())
.setAccessTime(newNode.getAccessTime())
.setBlockSize(newNode.getPreferredBlockSize())
.setBlocks(newNode.getBlocks())
.setPermissionStatus(newNode.getPermissionStatus());
logEdit(op);
}
/**
* Add create directory record to edit log
*/
public void logMkDir(String path, INode newNode) {
MkdirOp op = MkdirOp.getInstance()
.setPath(path)
.setTimestamp(newNode.getModificationTime())
.setPermissionStatus(newNode.getPermissionStatus());
logEdit(op);
}
/**
* Add rename record to edit log
* TODO: use String parameters until just before writing to disk
*/
void logRename(String src, String dst, long timestamp) {
RenameOldOp op = RenameOldOp.getInstance()
.setSource(src)
.setDestination(dst)
.setTimestamp(timestamp);
logEdit(op);
}
/**
* Add rename record to edit log
*/
void logRename(String src, String dst, long timestamp, Options.Rename... options) {
RenameOp op = RenameOp.getInstance()
.setSource(src)
.setDestination(dst)
.setTimestamp(timestamp)
.setOptions(options);
logEdit(op);
}
/**
* Add set replication record to edit log
*/
void logSetReplication(String src, short replication) {
SetReplicationOp op = SetReplicationOp.getInstance()
.setPath(src)
.setReplication(replication);
logEdit(op);
}
/** Add set namespace quota record to edit log
*
* @param src the string representation of the path to a directory
* @param quota the directory size limit
*/
void logSetQuota(String src, long nsQuota, long dsQuota) {
SetQuotaOp op = SetQuotaOp.getInstance()
.setSource(src)
.setNSQuota(nsQuota)
.setDSQuota(dsQuota);
logEdit(op);
}
/** Add set permissions record to edit log */
void logSetPermissions(String src, FsPermission permissions) {
SetPermissionsOp op = SetPermissionsOp.getInstance()
.setSource(src)
.setPermissions(permissions);
logEdit(op);
}
/** Add set owner record to edit log */
void logSetOwner(String src, String username, String groupname) {
SetOwnerOp op = SetOwnerOp.getInstance()
.setSource(src)
.setUser(username)
.setGroup(groupname);
logEdit(op);
}
/**
* concat(trg,src..) log
*/
void logConcat(String trg, String [] srcs, long timestamp) {
ConcatDeleteOp op = ConcatDeleteOp.getInstance()
.setTarget(trg)
.setSources(srcs)
.setTimestamp(timestamp);
logEdit(op);
}
/**
* Add delete file record to edit log
*/
void logDelete(String src, long timestamp) {
DeleteOp op = DeleteOp.getInstance()
.setPath(src)
.setTimestamp(timestamp);
logEdit(op);
}
/**
* Add generation stamp record to edit log
*/
void logGenerationStamp(long genstamp) {
SetGenstampOp op = SetGenstampOp.getInstance()
.setGenerationStamp(genstamp);
logEdit(op);
}
/**
* Add access time record to edit log
*/
void logTimes(String src, long mtime, long atime) {
TimesOp op = TimesOp.getInstance()
.setPath(src)
.setModificationTime(mtime)
.setAccessTime(atime);
logEdit(op);
}
/**
* Add a create symlink record.
*/
void logSymlink(String path, String value, long mtime,
long atime, INodeSymlink node) {
SymlinkOp op = SymlinkOp.getInstance()
.setPath(path)
.setValue(value)
.setModificationTime(mtime)
.setAccessTime(atime)
.setPermissionStatus(node.getPermissionStatus());
logEdit(op);
}
/**
* log delegation token to edit log
* @param id DelegationTokenIdentifier
* @param expiryTime of the token
* @return
*/
void logGetDelegationToken(DelegationTokenIdentifier id,
long expiryTime) {
GetDelegationTokenOp op = GetDelegationTokenOp.getInstance()
.setDelegationTokenIdentifier(id)
.setExpiryTime(expiryTime);
logEdit(op);
}
void logRenewDelegationToken(DelegationTokenIdentifier id,
long expiryTime) {
RenewDelegationTokenOp op = RenewDelegationTokenOp.getInstance()
.setDelegationTokenIdentifier(id)
.setExpiryTime(expiryTime);
logEdit(op);
}
void logCancelDelegationToken(DelegationTokenIdentifier id) {
CancelDelegationTokenOp op = CancelDelegationTokenOp.getInstance()
.setDelegationTokenIdentifier(id);
logEdit(op);
}
void logUpdateMasterKey(DelegationKey key) {
UpdateMasterKeyOp op = UpdateMasterKeyOp.getInstance()
.setDelegationKey(key);
logEdit(op);
}
void logReassignLease(String leaseHolder, String src, String newHolder) {
ReassignLeaseOp op = ReassignLeaseOp.getInstance()
.setLeaseHolder(leaseHolder)
.setPath(src)
.setNewHolder(newHolder);
logEdit(op);
}
/**
* @return the number of active (non-failed) journals
*/
private int countActiveJournals() {
int count = 0;
for (JournalAndStream jas : journals) {
if (jas.isActive()) {
count++;
}
}
return count;
}
/**
* Used only by unit tests.
*/
@VisibleForTesting
List<JournalAndStream> getJournals() {
return journals;
}
/**
* Return a manifest of what finalized edit logs are available
*/
public synchronized RemoteEditLogManifest getEditLogManifest(
long fromTxId) throws IOException {
// Collect RemoteEditLogs available from each FileJournalManager
List<RemoteEditLog> allLogs = Lists.newArrayList();
for (JournalAndStream j : journals) {
if (j.getManager() instanceof FileJournalManager) {
FileJournalManager fjm = (FileJournalManager)j.getManager();
try {
allLogs.addAll(fjm.getRemoteEditLogs(fromTxId));
} catch (Throwable t) {
LOG.warn("Cannot list edit logs in " + fjm, t);
}
}
}
// Group logs by their starting txid
ImmutableListMultimap<Long, RemoteEditLog> logsByStartTxId =
Multimaps.index(allLogs, RemoteEditLog.GET_START_TXID);
long curStartTxId = fromTxId;
List<RemoteEditLog> logs = Lists.newArrayList();
while (true) {
ImmutableList<RemoteEditLog> logGroup = logsByStartTxId.get(curStartTxId);
if (logGroup.isEmpty()) {
// we have a gap in logs - for example because we recovered some old
// storage directory with ancient logs. Clear out any logs we've
// accumulated so far, and then skip to the next segment of logs
// after the gap.
SortedSet<Long> startTxIds = Sets.newTreeSet(logsByStartTxId.keySet());
startTxIds = startTxIds.tailSet(curStartTxId);
if (startTxIds.isEmpty()) {
break;
} else {
if (LOG.isDebugEnabled()) {
LOG.debug("Found gap in logs at " + curStartTxId + ": " +
"not returning previous logs in manifest.");
}
logs.clear();
curStartTxId = startTxIds.first();
continue;
}
}
// Find the one that extends the farthest forward
RemoteEditLog bestLog = Collections.max(logGroup);
logs.add(bestLog);
// And then start looking from after that point
curStartTxId = bestLog.getEndTxId() + 1;
}
RemoteEditLogManifest ret = new RemoteEditLogManifest(logs);
if (LOG.isDebugEnabled()) {
LOG.debug("Generated manifest for logs since " + fromTxId + ":"
+ ret);
}
return ret;
}
/**
* Finalizes the current edit log and opens a new log segment.
* @return the transaction id of the BEGIN_LOG_SEGMENT transaction
* in the new log.
*/
synchronized long rollEditLog() throws IOException {
LOG.info("Rolling edit logs.");
endCurrentLogSegment(true);
long nextTxId = getLastWrittenTxId() + 1;
startLogSegment(nextTxId, true);
assert curSegmentTxId == nextTxId;
return nextTxId;
}
/**
* Start writing to the log segment with the given txid.
* Transitions from BETWEEN_LOG_SEGMENTS state to IN_LOG_SEGMENT state.
*/
synchronized void startLogSegment(final long segmentTxId,
boolean writeHeaderTxn) throws IOException {
LOG.info("Starting log segment at " + segmentTxId);
Preconditions.checkArgument(segmentTxId > 0,
"Bad txid: %s", segmentTxId);
Preconditions.checkState(state == State.BETWEEN_LOG_SEGMENTS,
"Bad state: %s", state);
Preconditions.checkState(segmentTxId > curSegmentTxId,
"Cannot start writing to log segment " + segmentTxId +
" when previous log segment started at " + curSegmentTxId);
Preconditions.checkArgument(segmentTxId == txid + 1,
"Cannot start log segment at txid %s when next expected " +
"txid is %s", segmentTxId, txid + 1);
numTransactions = totalTimeTransactions = numTransactionsBatchedInSync = 0;
// TODO no need to link this back to storage anymore!
// See HDFS-2174.
storage.attemptRestoreRemovedStorage();
mapJournalsAndReportErrors(new JournalClosure() {
@Override
public void apply(JournalAndStream jas) throws IOException {
jas.startLogSegment(segmentTxId);
}
}, "starting log segment " + segmentTxId);
if (countActiveJournals() == 0) {
throw new IOException("Unable to start log segment " +
segmentTxId + ": no journals successfully started.");
}
curSegmentTxId = segmentTxId;
state = State.IN_SEGMENT;
if (writeHeaderTxn) {
logEdit(LogSegmentOp.getInstance(
FSEditLogOpCodes.OP_START_LOG_SEGMENT));
logSync();
}
}
/**
* Finalize the current log segment.
* Transitions from IN_SEGMENT state to BETWEEN_LOG_SEGMENTS state.
*/
synchronized void endCurrentLogSegment(boolean writeEndTxn) {
LOG.info("Ending log segment " + curSegmentTxId);
Preconditions.checkState(state == State.IN_SEGMENT,
"Bad state: %s", state);
if (writeEndTxn) {
logEdit(LogSegmentOp.getInstance(
FSEditLogOpCodes.OP_END_LOG_SEGMENT));
logSync();
}
printStatistics(true);
final long lastTxId = getLastWrittenTxId();
mapJournalsAndReportErrors(new JournalClosure() {
@Override
public void apply(JournalAndStream jas) throws IOException {
if (jas.isActive()) {
jas.close(lastTxId);
}
}
}, "ending log segment");
state = State.BETWEEN_LOG_SEGMENTS;
}
/**
* Abort all current logs. Called from the backup node.
*/
synchronized void abortCurrentLogSegment() {
mapJournalsAndReportErrors(new JournalClosure() {
@Override
public void apply(JournalAndStream jas) throws IOException {
jas.abort();
}
}, "aborting all streams");
state = State.BETWEEN_LOG_SEGMENTS;
}
/**
* Archive any log files that are older than the given txid.
*/
public void purgeLogsOlderThan(final long minTxIdToKeep) {
synchronized (this) {
// synchronized to prevent findbugs warning about inconsistent
// synchronization. This will be JIT-ed out if asserts are
// off.
assert curSegmentTxId == HdfsConstants.INVALID_TXID || // on format this is no-op
minTxIdToKeep <= curSegmentTxId :
"cannot purge logs older than txid " + minTxIdToKeep +
" when current segment starts at " + curSegmentTxId;
}
mapJournalsAndReportErrors(new JournalClosure() {
@Override
public void apply(JournalAndStream jas) throws IOException {
jas.manager.purgeLogsOlderThan(minTxIdToKeep);
}
}, "purging logs older than " + minTxIdToKeep);
}
/**
* The actual sync activity happens while not synchronized on this object.
* Thus, synchronized activities that require that they are not concurrent
* with file operations should wait for any running sync to finish.
*/
synchronized void waitForSyncToFinish() {
while (isSyncRunning) {
try {
wait(1000);
} catch (InterruptedException ie) {}
}
}
/**
* Return the txid of the last synced transaction.
* For test use only
*/
synchronized long getSyncTxId() {
return synctxid;
}
// sets the initial capacity of the flush buffer.
public void setOutputBufferCapacity(int size) {
for (JournalAndStream jas : journals) {
jas.manager.setOutputBufferCapacity(size);
}
}
/**
* Create (or find if already exists) an edit output stream, which
* streams journal records (edits) to the specified backup node.<br>
*
* The new BackupNode will start receiving edits the next time this
* NameNode's logs roll.
*
* @param bnReg the backup node registration information.
* @param nnReg this (active) name-node registration.
* @throws IOException
*/
synchronized void registerBackupNode(
NamenodeRegistration bnReg, // backup node
NamenodeRegistration nnReg) // active name-node
throws IOException {
if(bnReg.isRole(NamenodeRole.CHECKPOINT))
return; // checkpoint node does not stream edits
JournalAndStream jas = findBackupJournalAndStream(bnReg);
if (jas != null) {
// already registered
LOG.info("Backup node " + bnReg + " re-registers");
return;
}
LOG.info("Registering new backup node: " + bnReg);
BackupJournalManager bjm = new BackupJournalManager(bnReg, nnReg);
journals.add(new JournalAndStream(bjm));
}
synchronized void releaseBackupStream(NamenodeRegistration registration) {
for (Iterator<JournalAndStream> iter = journals.iterator();
iter.hasNext();) {
JournalAndStream jas = iter.next();
if (jas.manager instanceof BackupJournalManager &&
((BackupJournalManager)jas.manager).matchesRegistration(
registration)) {
jas.abort();
LOG.info("Removing backup journal " + jas);
iter.remove();
}
}
}
/**
* Find the JournalAndStream associated with this BackupNode.
* @return null if it cannot be found
*/
private synchronized JournalAndStream findBackupJournalAndStream(
NamenodeRegistration bnReg) {
for (JournalAndStream jas : journals) {
if (jas.manager instanceof BackupJournalManager) {
BackupJournalManager bjm = (BackupJournalManager)jas.manager;
if (bjm.matchesRegistration(bnReg)) {
return jas;
}
}
}
return null;
}
/**
* Write an operation to the edit log. Do not sync to persistent
* store yet.
*/
synchronized void logEdit(final int length, final byte[] data) {
long start = beginTransaction();
mapJournalsAndReportErrors(new JournalClosure() {
@Override
public void apply(JournalAndStream jas) throws IOException {
if (jas.isActive()) {
jas.getCurrentStream().writeRaw(data, 0, length); // TODO writeRaw
}
}
}, "Logging edit");
endTransaction(start);
}
//// Iteration across journals
private interface JournalClosure {
public void apply(JournalAndStream jas) throws IOException;
}
/**
* Apply the given function across all of the journal managers, disabling
* any for which the closure throws an IOException.
* @param status message used for logging errors (e.g. "opening journal")
*/
private void mapJournalsAndReportErrors(
JournalClosure closure, String status) {
List<JournalAndStream> badJAS = Lists.newLinkedList();
for (JournalAndStream jas : journals) {
try {
closure.apply(jas);
} catch (Throwable t) {
LOG.error("Error " + status + " (journal " + jas + ")", t);
badJAS.add(jas);
}
}
disableAndReportErrorOnJournals(badJAS);
}
/**
* Called when some journals experience an error in some operation.
* This propagates errors to the storage level.
*/
private void disableAndReportErrorOnJournals(List<JournalAndStream> badJournals) {
if (badJournals == null || badJournals.isEmpty()) {
return; // nothing to do
}
for (JournalAndStream j : badJournals) {
LOG.error("Disabling journal " + j);
j.abort();
}
}
/**
* Container for a JournalManager paired with its currently
* active stream.
*
* If a Journal gets disabled due to an error writing to its
* stream, then the stream will be aborted and set to null.
*/
static class JournalAndStream {
private final JournalManager manager;
private EditLogOutputStream stream;
private long segmentStartsAtTxId = HdfsConstants.INVALID_TXID;
private JournalAndStream(JournalManager manager) {
this.manager = manager;
}
private void startLogSegment(long txId) throws IOException {
Preconditions.checkState(stream == null);
stream = manager.startLogSegment(txId);
segmentStartsAtTxId = txId;
}
private void close(long lastTxId) throws IOException {
Preconditions.checkArgument(lastTxId >= segmentStartsAtTxId,
"invalid segment: lastTxId %s >= " +
"segment starting txid %s", lastTxId, segmentStartsAtTxId);
if (stream == null) return;
stream.close();
manager.finalizeLogSegment(segmentStartsAtTxId, lastTxId);
stream = null;
}
@VisibleForTesting
void abort() {
if (stream == null) return;
try {
stream.abort();
} catch (IOException ioe) {
LOG.error("Unable to abort stream " + stream, ioe);
}
stream = null;
segmentStartsAtTxId = HdfsConstants.INVALID_TXID;
}
private boolean isActive() {
return stream != null;
}
@VisibleForTesting
EditLogOutputStream getCurrentStream() {
return stream;
}
@Override
public String toString() {
return "JournalAndStream(mgr=" + manager +
", " + "stream=" + stream + ")";
}
@VisibleForTesting
void setCurrentStreamForTests(EditLogOutputStream stream) {
this.stream = stream;
}
@VisibleForTesting
JournalManager getManager() {
return manager;
}
private EditLogInputStream getInProgressInputStream() throws IOException {
return manager.getInProgressInputStream(segmentStartsAtTxId);
}
}
/**
* @return an EditLogInputStream that reads from the same log that
* the edit log is currently writing. This is used from the BackupNode
* during edits synchronization.
* @throws IOException if no valid logs are available.
*/
synchronized EditLogInputStream getInProgressFileInputStream()
throws IOException {
for (JournalAndStream jas : journals) {
if (!jas.isActive()) continue;
try {
EditLogInputStream in = jas.getInProgressInputStream();
if (in != null) return in;
} catch (IOException ioe) {
LOG.warn("Unable to get the in-progress input stream from " + jas,
ioe);
}
}
throw new IOException("No in-progress stream provided edits");
}
}