hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetAsyncDiskService.java - hadoop-common - Git at Google

 /**
  * 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.datanode.fsdataset.impl;

 import java.io.File;
 import java.io.FileDescriptor;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;

 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.server.datanode.DataNode;
 import org.apache.hadoop.hdfs.server.protocol.BlockCommand;
 import org.apache.hadoop.io.nativeio.NativeIO;
 import org.apache.hadoop.io.nativeio.NativeIOException;

 /**
  * This class is a container of multiple thread pools, each for a volume,
  * so that we can schedule async disk operations easily.
  *
  * Examples of async disk operations are deletion of block files.
  * We don't want to create a new thread for each of the deletion request, and
  * we don't want to do all deletions in the heartbeat thread since deletion
  * can be slow, and we don't want to use a single thread pool because that
  * is inefficient when we have more than 1 volume.  AsyncDiskService is the
  * solution for these.
  * Another example of async disk operation is requesting sync_file_range().
  *
  * This class and {@link org.apache.hadoop.util.AsyncDiskService} are similar.
  * They should be combined.
  */
 class FsDatasetAsyncDiskService {
   public static final Log LOG = LogFactory.getLog(FsDatasetAsyncDiskService.class);

   // ThreadPool core pool size
   private static final int CORE_THREADS_PER_VOLUME = 1;
   // ThreadPool maximum pool size
   private static final int MAXIMUM_THREADS_PER_VOLUME = 4;
   // ThreadPool keep-alive time for threads over core pool size
   private static final long THREADS_KEEP_ALIVE_SECONDS = 60;

   private final DataNode datanode;
   private final ThreadGroup threadGroup;
   private Map<File, ThreadPoolExecutor> executors
       = new HashMap<File, ThreadPoolExecutor>();

   /**
    * Create a AsyncDiskServices with a set of volumes (specified by their
    * root directories).
    *
    * The AsyncDiskServices uses one ThreadPool per volume to do the async
    * disk operations.
    */
   FsDatasetAsyncDiskService(DataNode datanode) {
     this.datanode = datanode;
     this.threadGroup = new ThreadGroup(getClass().getSimpleName());
   }

   private void addExecutorForVolume(final File volume) {
     ThreadFactory threadFactory = new ThreadFactory() {
       int counter = 0;

       @Override
       public Thread newThread(Runnable r) {
         int thisIndex;
         synchronized (this) {
           thisIndex = counter++;
         }
         Thread t = new Thread(threadGroup, r);
         t.setName("Async disk worker #" + thisIndex +
             " for volume " + volume);
         return t;
       }
     };

     ThreadPoolExecutor executor = new ThreadPoolExecutor(
         CORE_THREADS_PER_VOLUME, MAXIMUM_THREADS_PER_VOLUME,
         THREADS_KEEP_ALIVE_SECONDS, TimeUnit.SECONDS,
         new LinkedBlockingQueue<Runnable>(), threadFactory);

     // This can reduce the number of running threads
     executor.allowCoreThreadTimeOut(true);
     executors.put(volume, executor);
   }

   /**
    * Starts AsyncDiskService for a new volume
    * @param volume the root of the new data volume.
    */
   synchronized void addVolume(File volume) {
     if (executors == null) {
       throw new RuntimeException("AsyncDiskService is already shutdown");
     }
     ThreadPoolExecutor executor = executors.get(volume);
     if (executor != null) {
       throw new RuntimeException("Volume " + volume + " is already existed.");
     }
     addExecutorForVolume(volume);
   }

   synchronized long countPendingDeletions() {
     long count = 0;
     for (ThreadPoolExecutor exec : executors.values()) {
       count += exec.getTaskCount() - exec.getCompletedTaskCount();
     }
     return count;
   }

   /**
    * Execute the task sometime in the future, using ThreadPools.
    */
   synchronized void execute(File root, Runnable task) {
     if (executors == null) {
       throw new RuntimeException("AsyncDiskService is already shutdown");
     }
     ThreadPoolExecutor executor = executors.get(root);
     if (executor == null) {
       throw new RuntimeException("Cannot find root " + root
           + " for execution of task " + task);
     } else {
       executor.execute(task);
     }
   }

   /**
    * Gracefully shut down all ThreadPool. Will wait for all deletion
    * tasks to finish.
    */
   synchronized void shutdown() {
     if (executors == null) {
       LOG.warn("AsyncDiskService has already shut down.");
     } else {
       LOG.info("Shutting down all async disk service threads");

       for (Map.Entry<File, ThreadPoolExecutor> e : executors.entrySet()) {
         e.getValue().shutdown();
       }
       // clear the executor map so that calling execute again will fail.
       executors = null;

       LOG.info("All async disk service threads have been shut down");
     }
   }

   public void submitSyncFileRangeRequest(FsVolumeImpl volume,
       final FileDescriptor fd, final long offset, final long nbytes,
       final int flags) {
     execute(volume.getCurrentDir(), new Runnable() {
       @Override
       public void run() {
         try {
           NativeIO.POSIX.syncFileRangeIfPossible(fd, offset, nbytes, flags);
         } catch (NativeIOException e) {
           LOG.warn("sync_file_range error", e);
         }
       }
     });
   }

   /**
    * Delete the block file and meta file from the disk asynchronously, adjust
    * dfsUsed statistics accordingly.
    */
   void deleteAsync(FsVolumeImpl volume, File blockFile, File metaFile,
       ExtendedBlock block, String trashDirectory) {
     LOG.info("Scheduling " + block.getLocalBlock()
         + " file " + blockFile + " for deletion");
     ReplicaFileDeleteTask deletionTask = new ReplicaFileDeleteTask(
         volume, blockFile, metaFile, block, trashDirectory);
     execute(volume.getCurrentDir(), deletionTask);
   }

   /** A task for deleting a block file and its associated meta file, as well
    *  as decrement the dfs usage of the volume.
    *  Optionally accepts a trash directory. If one is specified then the files
    *  are moved to trash instead of being deleted. If none is specified then the
    *  files are deleted immediately.
    */
   class ReplicaFileDeleteTask implements Runnable {
     final FsVolumeImpl volume;
     final File blockFile;
     final File metaFile;
     final ExtendedBlock block;
     final String trashDirectory;

     ReplicaFileDeleteTask(FsVolumeImpl volume, File blockFile,
         File metaFile, ExtendedBlock block, String trashDirectory) {
       this.volume = volume;
       this.blockFile = blockFile;
       this.metaFile = metaFile;
       this.block = block;
       this.trashDirectory = trashDirectory;
     }

     @Override
     public String toString() {
       // Called in AsyncDiskService.execute for displaying error messages.
       return "deletion of block " + block.getBlockPoolId() + " "
           + block.getLocalBlock() + " with block file " + blockFile
           + " and meta file " + metaFile + " from volume " + volume;
     }

     private boolean deleteFiles() {
       return blockFile.delete() && (metaFile.delete() || !metaFile.exists());
     }

     private boolean moveFiles() {
       File trashDirFile = new File(trashDirectory);
       if (!trashDirFile.exists() && !trashDirFile.mkdirs()) {
         LOG.error("Failed to create trash directory " + trashDirectory);
         return false;
       }

       if (LOG.isDebugEnabled()) {
         LOG.debug("Moving files " + blockFile.getName() + " and " +
             metaFile.getName() + " to trash.");
       }

       File newBlockFile = new File(trashDirectory, blockFile.getName());
       File newMetaFile = new File(trashDirectory, metaFile.getName());
       return (blockFile.renameTo(newBlockFile) &&
               metaFile.renameTo(newMetaFile));
     }

     @Override
     public void run() {
       long dfsBytes = blockFile.length() + metaFile.length();
       boolean result;

       result = (trashDirectory == null) ? deleteFiles() : moveFiles();

       if (!result) {
         LOG.warn("Unexpected error trying to "
             + (trashDirectory == null ? "delete" : "move")
             + " block " + block.getBlockPoolId() + " " + block.getLocalBlock()
             + " at file " + blockFile + ". Ignored.");
       } else {
         if(block.getLocalBlock().getNumBytes() != BlockCommand.NO_ACK){
           datanode.notifyNamenodeDeletedBlock(block, volume.getStorageID());
         }
         volume.decDfsUsed(block.getBlockPoolId(), dfsBytes);
         LOG.info("Deleted " + block.getBlockPoolId() + " "
             + block.getLocalBlock() + " file " + blockFile);
       }
     }
   }
 }
	/**
	* 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.datanode.fsdataset.impl;

	import java.io.File;
	import java.io.FileDescriptor;
	import java.util.HashMap;
	import java.util.Map;
	import java.util.concurrent.LinkedBlockingQueue;
	import java.util.concurrent.ThreadFactory;
	import java.util.concurrent.ThreadPoolExecutor;
	import java.util.concurrent.TimeUnit;

	import org.apache.commons.logging.Log;
	import org.apache.commons.logging.LogFactory;
	import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
	import org.apache.hadoop.hdfs.server.datanode.DataNode;
	import org.apache.hadoop.hdfs.server.protocol.BlockCommand;
	import org.apache.hadoop.io.nativeio.NativeIO;
	import org.apache.hadoop.io.nativeio.NativeIOException;

	/**
	* This class is a container of multiple thread pools, each for a volume,
	* so that we can schedule async disk operations easily.
	*
	* Examples of async disk operations are deletion of block files.
	* We don't want to create a new thread for each of the deletion request, and
	* we don't want to do all deletions in the heartbeat thread since deletion
	* can be slow, and we don't want to use a single thread pool because that
	* is inefficient when we have more than 1 volume. AsyncDiskService is the
	* solution for these.
	* Another example of async disk operation is requesting sync_file_range().
	*
	* This class and {@link org.apache.hadoop.util.AsyncDiskService} are similar.
	* They should be combined.
	*/
	class FsDatasetAsyncDiskService {
	public static final Log LOG = LogFactory.getLog(FsDatasetAsyncDiskService.class);

	// ThreadPool core pool size
	private static final int CORE_THREADS_PER_VOLUME = 1;
	// ThreadPool maximum pool size
	private static final int MAXIMUM_THREADS_PER_VOLUME = 4;
	// ThreadPool keep-alive time for threads over core pool size
	private static final long THREADS_KEEP_ALIVE_SECONDS = 60;

	private final DataNode datanode;
	private final ThreadGroup threadGroup;
	private Map<File, ThreadPoolExecutor> executors
	= new HashMap<File, ThreadPoolExecutor>();

	/**
	* Create a AsyncDiskServices with a set of volumes (specified by their
	* root directories).
	*
	* The AsyncDiskServices uses one ThreadPool per volume to do the async
	* disk operations.
	*/
	FsDatasetAsyncDiskService(DataNode datanode) {
	this.datanode = datanode;
	this.threadGroup = new ThreadGroup(getClass().getSimpleName());
	}

	private void addExecutorForVolume(final File volume) {
	ThreadFactory threadFactory = new ThreadFactory() {
	int counter = 0;

	@Override
	public Thread newThread(Runnable r) {
	int thisIndex;
	synchronized (this) {
	thisIndex = counter++;
	}
	Thread t = new Thread(threadGroup, r);
	t.setName("Async disk worker #" + thisIndex +
	" for volume " + volume);
	return t;
	}
	};

	ThreadPoolExecutor executor = new ThreadPoolExecutor(
	CORE_THREADS_PER_VOLUME, MAXIMUM_THREADS_PER_VOLUME,
	THREADS_KEEP_ALIVE_SECONDS, TimeUnit.SECONDS,
	new LinkedBlockingQueue<Runnable>(), threadFactory);

	// This can reduce the number of running threads
	executor.allowCoreThreadTimeOut(true);
	executors.put(volume, executor);
	}

	/**
	* Starts AsyncDiskService for a new volume
	* @param volume the root of the new data volume.
	*/
	synchronized void addVolume(File volume) {
	if (executors == null) {
	throw new RuntimeException("AsyncDiskService is already shutdown");
	}
	ThreadPoolExecutor executor = executors.get(volume);
	if (executor != null) {
	throw new RuntimeException("Volume " + volume + " is already existed.");
	}
	addExecutorForVolume(volume);
	}

	synchronized long countPendingDeletions() {
	long count = 0;
	for (ThreadPoolExecutor exec : executors.values()) {
	count += exec.getTaskCount() - exec.getCompletedTaskCount();
	}
	return count;
	}

	/**
	* Execute the task sometime in the future, using ThreadPools.
	*/
	synchronized void execute(File root, Runnable task) {
	if (executors == null) {
	throw new RuntimeException("AsyncDiskService is already shutdown");
	}
	ThreadPoolExecutor executor = executors.get(root);
	if (executor == null) {
	throw new RuntimeException("Cannot find root " + root
	+ " for execution of task " + task);
	} else {
	executor.execute(task);
	}
	}

	/**
	* Gracefully shut down all ThreadPool. Will wait for all deletion
	* tasks to finish.
	*/
	synchronized void shutdown() {
	if (executors == null) {
	LOG.warn("AsyncDiskService has already shut down.");
	} else {
	LOG.info("Shutting down all async disk service threads");

	for (Map.Entry<File, ThreadPoolExecutor> e : executors.entrySet()) {
	e.getValue().shutdown();
	}
	// clear the executor map so that calling execute again will fail.
	executors = null;

	LOG.info("All async disk service threads have been shut down");
	}
	}

	public void submitSyncFileRangeRequest(FsVolumeImpl volume,
	final FileDescriptor fd, final long offset, final long nbytes,
	final int flags) {
	execute(volume.getCurrentDir(), new Runnable() {
	@Override
	public void run() {
	try {
	NativeIO.POSIX.syncFileRangeIfPossible(fd, offset, nbytes, flags);
	} catch (NativeIOException e) {
	LOG.warn("sync_file_range error", e);
	}
	}
	});
	}

	/**
	* Delete the block file and meta file from the disk asynchronously, adjust
	* dfsUsed statistics accordingly.
	*/
	void deleteAsync(FsVolumeImpl volume, File blockFile, File metaFile,
	ExtendedBlock block, String trashDirectory) {
	LOG.info("Scheduling " + block.getLocalBlock()
	+ " file " + blockFile + " for deletion");
	ReplicaFileDeleteTask deletionTask = new ReplicaFileDeleteTask(
	volume, blockFile, metaFile, block, trashDirectory);
	execute(volume.getCurrentDir(), deletionTask);
	}

	/** A task for deleting a block file and its associated meta file, as well
	* as decrement the dfs usage of the volume.
	* Optionally accepts a trash directory. If one is specified then the files
	* are moved to trash instead of being deleted. If none is specified then the
	* files are deleted immediately.
	*/
	class ReplicaFileDeleteTask implements Runnable {
	final FsVolumeImpl volume;
	final File blockFile;
	final File metaFile;
	final ExtendedBlock block;
	final String trashDirectory;

	ReplicaFileDeleteTask(FsVolumeImpl volume, File blockFile,
	File metaFile, ExtendedBlock block, String trashDirectory) {
	this.volume = volume;
	this.blockFile = blockFile;
	this.metaFile = metaFile;
	this.block = block;
	this.trashDirectory = trashDirectory;
	}

	@Override
	public String toString() {
	// Called in AsyncDiskService.execute for displaying error messages.
	return "deletion of block " + block.getBlockPoolId() + " "
	+ block.getLocalBlock() + " with block file " + blockFile
	+ " and meta file " + metaFile + " from volume " + volume;
	}

	private boolean deleteFiles() {
	return blockFile.delete() && (metaFile.delete() \|\| !metaFile.exists());
	}

	private boolean moveFiles() {
	File trashDirFile = new File(trashDirectory);
	if (!trashDirFile.exists() && !trashDirFile.mkdirs()) {
	LOG.error("Failed to create trash directory " + trashDirectory);
	return false;
	}

	if (LOG.isDebugEnabled()) {
	LOG.debug("Moving files " + blockFile.getName() + " and " +
	metaFile.getName() + " to trash.");
	}

	File newBlockFile = new File(trashDirectory, blockFile.getName());
	File newMetaFile = new File(trashDirectory, metaFile.getName());
	return (blockFile.renameTo(newBlockFile) &&
	metaFile.renameTo(newMetaFile));
	}

	@Override
	public void run() {
	long dfsBytes = blockFile.length() + metaFile.length();
	boolean result;

	result = (trashDirectory == null) ? deleteFiles() : moveFiles();

	if (!result) {
	LOG.warn("Unexpected error trying to "
	+ (trashDirectory == null ? "delete" : "move")
	+ " block " + block.getBlockPoolId() + " " + block.getLocalBlock()
	+ " at file " + blockFile + ". Ignored.");
	} else {
	if(block.getLocalBlock().getNumBytes() != BlockCommand.NO_ACK){
	datanode.notifyNamenodeDeletedBlock(block, volume.getStorageID());
	}
	volume.decDfsUsed(block.getBlockPoolId(), dfsBytes);
	LOG.info("Deleted " + block.getBlockPoolId() + " "
	+ block.getLocalBlock() + " file " + blockFile);
	}
	}
	}
	}