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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.namenode;
import java.util.*;
import org.apache.hadoop.hdfs.protocol.Block;
/* Class for keeping track of under replication blocks
* Blocks have replication priority, with priority 0 indicating the highest
* Blocks have only one replicas has the highest
*/
class UnderReplicatedBlocks implements Iterable {
static final int LEVEL = 4;
static public final int QUEUE_WITH_CORRUPT_BLOCKS = 2;
private List> priorityQueues = new ArrayList>();
/* constructor */
UnderReplicatedBlocks() {
for(int i=0; i());
}
}
/**
* Empty the queues.
*/
void clear() {
for(int i=0; i set:priorityQueues) {
if(set.contains(block)) { return true; }
}
return false;
}
/* Return the priority of a block
* @param block a under replication block
* @param curReplicas current number of replicas of the block
* @param expectedReplicas expected number of replicas of the block
*/
private int getPriority(Block block,
int curReplicas,
int decommissionedReplicas,
int expectedReplicas) {
assert curReplicas >= 0 : "Negative replicas!";
if (curReplicas >= expectedReplicas) {
return 3; // Block doesn't have enough racks
} else if(curReplicas==0) {
// If there are zero non-decommissioned replica but there are
// some decommissioned replicas, then assign them highest priority
if (decommissionedReplicas > 0) {
return 0;
}
return QUEUE_WITH_CORRUPT_BLOCKS; // keep these blocks in needed replication.
} else if(curReplicas==1) {
return 0; // highest priority
} else if(curReplicas*3= 0 : "Negative replicas!";
int priLevel = getPriority(block, curReplicas, decomissionedReplicas,
expectedReplicas);
if(priLevel != LEVEL && priorityQueues.get(priLevel).add(block)) {
if(NameNode.stateChangeLog.isDebugEnabled()) {
NameNode.stateChangeLog.debug(
"BLOCK* NameSystem.UnderReplicationBlock.add:"
+ block
+ " has only "+curReplicas
+ " replicas and need " + expectedReplicas
+ " replicas so is added to neededReplications"
+ " at priority level " + priLevel);
}
return true;
}
return false;
}
/* remove a block from a under replication queue */
synchronized boolean remove(Block block,
int oldReplicas,
int decommissionedReplicas,
int oldExpectedReplicas) {
int priLevel = getPriority(block, oldReplicas,
decommissionedReplicas,
oldExpectedReplicas);
return remove(block, priLevel);
}
/* remove a block from a under replication queue given a priority*/
boolean remove(Block block, int priLevel) {
if(priLevel >= 0 && priLevel < LEVEL
&& priorityQueues.get(priLevel).remove(block)) {
if(NameNode.stateChangeLog.isDebugEnabled()) {
NameNode.stateChangeLog.debug(
"BLOCK* NameSystem.UnderReplicationBlock.remove: "
+ "Removing block " + block
+ " from priority queue "+ priLevel);
}
return true;
} else {
// Try to remove the block from all queues if the block was
// not found in the queue for the given priority level.
for(int i=0; i {
private int level;
private boolean isIteratorForLevel = false;
private List> iterators = new ArrayList>();
BlockIterator()
{
level=0;
for(int i=0; i