org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.ReplicaMap Maven / Gradle / Ivy
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* 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.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.locks.ReadWriteLock;
import org.apache.hadoop.HadoopIllegalArgumentException;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo;
import org.apache.hadoop.util.LightWeightResizableGSet;
import org.apache.hadoop.util.AutoCloseableLock;
/**
* Maintains the replica map.
*/
class ReplicaMap {
// Lock object to synchronize this instance.
private final AutoCloseableLock readLock;
private final AutoCloseableLock writeLock;
// Map of block pool Id to another map of block Id to ReplicaInfo.
private final Map> map =
new HashMap<>();
ReplicaMap(AutoCloseableLock rLock, AutoCloseableLock wLock) {
if (rLock == null || wLock == null) {
throw new HadoopIllegalArgumentException(
"Lock to synchronize on cannot be null");
}
this.readLock = rLock;
this.writeLock = wLock;
}
ReplicaMap(ReadWriteLock lock) {
this(new AutoCloseableLock(lock.readLock()),
new AutoCloseableLock(lock.writeLock()));
}
String[] getBlockPoolList() {
try (AutoCloseableLock l = readLock.acquire()) {
return map.keySet().toArray(new String[map.keySet().size()]);
}
}
private void checkBlockPool(String bpid) {
if (bpid == null) {
throw new IllegalArgumentException("Block Pool Id is null");
}
}
private void checkBlock(Block b) {
if (b == null) {
throw new IllegalArgumentException("Block is null");
}
}
/**
* Get the meta information of the replica that matches both block id
* and generation stamp
* @param bpid block pool id
* @param block block with its id as the key
* @return the replica's meta information
* @throws IllegalArgumentException if the input block or block pool is null
*/
ReplicaInfo get(String bpid, Block block) {
checkBlockPool(bpid);
checkBlock(block);
ReplicaInfo replicaInfo = get(bpid, block.getBlockId());
if (replicaInfo != null &&
block.getGenerationStamp() == replicaInfo.getGenerationStamp()) {
return replicaInfo;
}
return null;
}
/**
* Get the meta information of the replica that matches the block id
* @param bpid block pool id
* @param blockId a block's id
* @return the replica's meta information
*/
ReplicaInfo get(String bpid, long blockId) {
checkBlockPool(bpid);
try (AutoCloseableLock l = readLock.acquire()) {
LightWeightResizableGSet m = map.get(bpid);
return m != null ? m.get(new Block(blockId)) : null;
}
}
/**
* Add a replica's meta information into the map
*
* @param bpid block pool id
* @param replicaInfo a replica's meta information
* @return previous meta information of the replica
* @throws IllegalArgumentException if the input parameter is null
*/
ReplicaInfo add(String bpid, ReplicaInfo replicaInfo) {
checkBlockPool(bpid);
checkBlock(replicaInfo);
try (AutoCloseableLock l = writeLock.acquire()) {
LightWeightResizableGSet m = map.get(bpid);
if (m == null) {
// Add an entry for block pool if it does not exist already
m = new LightWeightResizableGSet();
map.put(bpid, m);
}
return m.put(replicaInfo);
}
}
/**
* Add a replica's meta information into the map, if already exist
* return the old replicaInfo.
*/
ReplicaInfo addAndGet(String bpid, ReplicaInfo replicaInfo) {
checkBlockPool(bpid);
checkBlock(replicaInfo);
try (AutoCloseableLock l = writeLock.acquire()) {
LightWeightResizableGSet m = map.get(bpid);
if (m == null) {
// Add an entry for block pool if it does not exist already
m = new LightWeightResizableGSet();
map.put(bpid, m);
}
ReplicaInfo oldReplicaInfo = m.get(replicaInfo);
if (oldReplicaInfo != null) {
return oldReplicaInfo;
} else {
m.put(replicaInfo);
}
return replicaInfo;
}
}
/**
* Add all entries from the given replica map into the local replica map.
*/
void addAll(ReplicaMap other) {
map.putAll(other.map);
}
/**
* Merge all entries from the given replica map into the local replica map.
*/
void mergeAll(ReplicaMap other) {
other.map.forEach(
(bp, replicaInfos) -> {
replicaInfos.forEach(
replicaInfo -> add(bp, replicaInfo)
);
}
);
}
/**
* Remove the replica's meta information from the map that matches
* the input block's id and generation stamp
* @param bpid block pool id
* @param block block with its id as the key
* @return the removed replica's meta information
* @throws IllegalArgumentException if the input block is null
*/
ReplicaInfo remove(String bpid, Block block) {
checkBlockPool(bpid);
checkBlock(block);
try (AutoCloseableLock l = writeLock.acquire()) {
LightWeightResizableGSet m = map.get(bpid);
if (m != null) {
ReplicaInfo replicaInfo = m.get(block);
if (replicaInfo != null &&
block.getGenerationStamp() == replicaInfo.getGenerationStamp()) {
return m.remove(block);
}
}
}
return null;
}
/**
* Remove the replica's meta information from the map if present
* @param bpid block pool id
* @param blockId block id of the replica to be removed
* @return the removed replica's meta information
*/
ReplicaInfo remove(String bpid, long blockId) {
checkBlockPool(bpid);
try (AutoCloseableLock l = writeLock.acquire()) {
LightWeightResizableGSet m = map.get(bpid);
if (m != null) {
return m.remove(new Block(blockId));
}
}
return null;
}
/**
* Get the size of the map for given block pool
* @param bpid block pool id
* @return the number of replicas in the map
*/
int size(String bpid) {
try (AutoCloseableLock l = readLock.acquire()) {
LightWeightResizableGSet m = map.get(bpid);
return m != null ? m.size() : 0;
}
}
/**
* Get a collection of the replicas for given block pool
* This method is not synchronized. It needs to be synchronized
* externally using the lock, both for getting the replicas
* values from the map and iterating over it. Mutex can be accessed using
* {@link #getLock()} method.
*
* @param bpid block pool id
* @return a collection of the replicas belonging to the block pool
*/
Collection replicas(String bpid) {
LightWeightResizableGSet m = null;
m = map.get(bpid);
return m != null ? m.values() : null;
}
void initBlockPool(String bpid) {
checkBlockPool(bpid);
try (AutoCloseableLock l = writeLock.acquire()) {
LightWeightResizableGSet m = map.get(bpid);
if (m == null) {
// Add an entry for block pool if it does not exist already
m = new LightWeightResizableGSet();
map.put(bpid, m);
}
}
}
void cleanUpBlockPool(String bpid) {
checkBlockPool(bpid);
try (AutoCloseableLock l = writeLock.acquire()) {
map.remove(bpid);
}
}
/**
* Get the lock object used for synchronizing ReplicasMap
* @return lock object
*/
AutoCloseableLock getLock() {
return writeLock;
}
/**
* Get the lock object used for synchronizing the ReplicasMap for read only
* operations.
* @return The read lock object
*/
AutoCloseableLock getReadLock() {
return readLock;
}
}