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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.blockmanagement;
import java.io.IOException;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import com.google.common.base.Preconditions;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.fs.StorageType;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.protocol.BlockType;
import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.BlockUCState;
import org.apache.hadoop.util.LightWeightGSet;
import static org.apache.hadoop.hdfs.server.namenode.INodeId.INVALID_INODE_ID;
/**
* For a given block (or an erasure coding block group), BlockInfo class
* maintains 1) the {@link BlockCollection} it is part of, and 2) datanodes
* where the replicas of the block, or blocks belonging to the erasure coding
* block group, are stored.
*/
@InterfaceAudience.Private
public abstract class BlockInfo extends Block
implements LightWeightGSet.LinkedElement {
public static final BlockInfo[] EMPTY_ARRAY = {};
/**
* Replication factor.
*/
private short replication;
/**
* Block collection ID.
*/
private volatile long bcId;
/** For implementing {@link LightWeightGSet.LinkedElement} interface. */
private LightWeightGSet.LinkedElement nextLinkedElement;
/**
* This array contains triplets of references. For each i-th storage, the
* block belongs to triplets[3*i] is the reference to the
* {@link DatanodeStorageInfo} and triplets[3*i+1] and triplets[3*i+2] are
* references to the previous and the next blocks, respectively, in the list
* of blocks belonging to this storage.
*
* Using previous and next in Object triplets is done instead of a
* {@link LinkedList} list to efficiently use memory. With LinkedList the cost
* per replica is 42 bytes (LinkedList#Entry object per replica) versus 16
* bytes using the triplets.
*/
protected Object[] triplets;
private BlockUnderConstructionFeature uc;
/**
* Construct an entry for blocksmap
* @param size the block's replication factor, or the total number of blocks
* in the block group
*/
public BlockInfo(short size) {
this.triplets = new Object[3 * size];
this.bcId = INVALID_INODE_ID;
this.replication = isStriped() ? 0 : size;
}
public BlockInfo(Block blk, short size) {
super(blk);
this.triplets = new Object[3*size];
this.bcId = INVALID_INODE_ID;
this.replication = isStriped() ? 0 : size;
}
public short getReplication() {
return replication;
}
public void setReplication(short repl) {
this.replication = repl;
}
public long getBlockCollectionId() {
return bcId;
}
public void setBlockCollectionId(long id) {
this.bcId = id;
}
public void delete() {
setBlockCollectionId(INVALID_INODE_ID);
}
public boolean isDeleted() {
return bcId == INVALID_INODE_ID;
}
public Iterator getStorageInfos() {
return new BlocksMap.StorageIterator(this);
}
public DatanodeDescriptor getDatanode(int index) {
DatanodeStorageInfo storage = getStorageInfo(index);
return storage == null ? null : storage.getDatanodeDescriptor();
}
DatanodeStorageInfo getStorageInfo(int index) {
assert this.triplets != null : "BlockInfo is not initialized";
assert index >= 0 && index*3 < triplets.length : "Index is out of bound";
return (DatanodeStorageInfo)triplets[index*3];
}
BlockInfo getPrevious(int index) {
assert this.triplets != null : "BlockInfo is not initialized";
assert index >= 0 && index*3+1 < triplets.length : "Index is out of bound";
BlockInfo info = (BlockInfo)triplets[index*3+1];
assert info == null ||
info.getClass().getName().startsWith(BlockInfo.class.getName()) :
"BlockInfo is expected at " + index*3;
return info;
}
BlockInfo getNext(int index) {
assert this.triplets != null : "BlockInfo is not initialized";
assert index >= 0 && index*3+2 < triplets.length : "Index is out of bound";
BlockInfo info = (BlockInfo)triplets[index*3+2];
assert info == null || info.getClass().getName().startsWith(
BlockInfo.class.getName()) :
"BlockInfo is expected at " + index*3;
return info;
}
void setStorageInfo(int index, DatanodeStorageInfo storage) {
assert this.triplets != null : "BlockInfo is not initialized";
assert index >= 0 && index*3 < triplets.length : "Index is out of bound";
triplets[index*3] = storage;
}
/**
* Return the previous block on the block list for the datanode at
* position index. Set the previous block on the list to "to".
*
* @param index - the datanode index
* @param to - block to be set to previous on the list of blocks
* @return current previous block on the list of blocks
*/
BlockInfo setPrevious(int index, BlockInfo to) {
assert this.triplets != null : "BlockInfo is not initialized";
assert index >= 0 && index*3+1 < triplets.length : "Index is out of bound";
BlockInfo info = (BlockInfo) triplets[index*3+1];
triplets[index*3+1] = to;
return info;
}
/**
* Return the next block on the block list for the datanode at
* position index. Set the next block on the list to "to".
*
* @param index - the datanode index
* @param to - block to be set to next on the list of blocks
* @return current next block on the list of blocks
*/
BlockInfo setNext(int index, BlockInfo to) {
assert this.triplets != null : "BlockInfo is not initialized";
assert index >= 0 && index*3+2 < triplets.length : "Index is out of bound";
BlockInfo info = (BlockInfo) triplets[index*3+2];
triplets[index*3+2] = to;
return info;
}
public int getCapacity() {
assert this.triplets != null : "BlockInfo is not initialized";
assert triplets.length % 3 == 0 : "Malformed BlockInfo";
return triplets.length / 3;
}
/**
* Count the number of data-nodes the block currently belongs to (i.e., NN
* has received block reports from the DN).
*/
public abstract int numNodes();
/**
* Add a {@link DatanodeStorageInfo} location for a block
* @param storage The storage to add
* @param reportedBlock The block reported from the datanode. This is only
* used by erasure coded blocks, this block's id contains
* information indicating the index of the block in the
* corresponding block group.
*/
abstract boolean addStorage(DatanodeStorageInfo storage, Block reportedBlock);
/**
* Remove {@link DatanodeStorageInfo} location for a block
*/
abstract boolean removeStorage(DatanodeStorageInfo storage);
public abstract boolean isStriped();
public abstract BlockType getBlockType();
/** @return true if there is no datanode storage associated with the block */
abstract boolean hasNoStorage();
/**
* Find specified DatanodeStorageInfo.
* @return DatanodeStorageInfo or null if not found.
*/
DatanodeStorageInfo findStorageInfo(DatanodeDescriptor dn) {
int len = getCapacity();
DatanodeStorageInfo providedStorageInfo = null;
for(int idx = 0; idx < len; idx++) {
DatanodeStorageInfo cur = getStorageInfo(idx);
if(cur != null) {
if (cur.getStorageType() == StorageType.PROVIDED) {
// if block resides on provided storage, only match the storage ids
if (dn.getStorageInfo(cur.getStorageID()) != null) {
// do not return here as we have to check the other
// DatanodeStorageInfos for this block which could be local
providedStorageInfo = cur;
}
} else if (cur.getDatanodeDescriptor() == dn) {
return cur;
}
}
}
return providedStorageInfo;
}
/**
* Find specified DatanodeStorageInfo.
* @return index or -1 if not found.
*/
int findStorageInfo(DatanodeStorageInfo storageInfo) {
int len = getCapacity();
for(int idx = 0; idx < len; idx++) {
DatanodeStorageInfo cur = getStorageInfo(idx);
if (cur == storageInfo) {
return idx;
}
}
return -1;
}
/**
* Insert this block into the head of the list of blocks
* related to the specified DatanodeStorageInfo.
* If the head is null then form a new list.
* @return current block as the new head of the list.
*/
BlockInfo listInsert(BlockInfo head, DatanodeStorageInfo storage) {
int dnIndex = this.findStorageInfo(storage);
assert dnIndex >= 0 : "Data node is not found: current";
assert getPrevious(dnIndex) == null && getNext(dnIndex) == null :
"Block is already in the list and cannot be inserted.";
this.setPrevious(dnIndex, null);
this.setNext(dnIndex, head);
if (head != null) {
head.setPrevious(head.findStorageInfo(storage), this);
}
return this;
}
/**
* Remove this block from the list of blocks
* related to the specified DatanodeStorageInfo.
* If this block is the head of the list then return the next block as
* the new head.
* @return the new head of the list or null if the list becomes
* empy after deletion.
*/
BlockInfo listRemove(BlockInfo head, DatanodeStorageInfo storage) {
if (head == null) {
return null;
}
int dnIndex = this.findStorageInfo(storage);
if (dnIndex < 0) { // this block is not on the data-node list
return head;
}
BlockInfo next = this.getNext(dnIndex);
BlockInfo prev = this.getPrevious(dnIndex);
this.setNext(dnIndex, null);
this.setPrevious(dnIndex, null);
if (prev != null) {
prev.setNext(prev.findStorageInfo(storage), next);
}
if (next != null) {
next.setPrevious(next.findStorageInfo(storage), prev);
}
if (this == head) { // removing the head
head = next;
}
return head;
}
/**
* Remove this block from the list of blocks related to the specified
* DatanodeDescriptor. Insert it into the head of the list of blocks.
*
* @return the new head of the list.
*/
public BlockInfo moveBlockToHead(BlockInfo head, DatanodeStorageInfo storage,
int curIndex, int headIndex) {
if (head == this) {
return this;
}
BlockInfo next = this.setNext(curIndex, head);
BlockInfo prev = this.setPrevious(curIndex, null);
head.setPrevious(headIndex, this);
prev.setNext(prev.findStorageInfo(storage), next);
if (next != null) {
next.setPrevious(next.findStorageInfo(storage), prev);
}
return this;
}
@Override
public int hashCode() {
// Super implementation is sufficient
return super.hashCode();
}
@Override
public boolean equals(Object obj) {
// Sufficient to rely on super's implementation
return (this == obj) || super.equals(obj);
}
@Override
public LightWeightGSet.LinkedElement getNext() {
return nextLinkedElement;
}
@Override
public void setNext(LightWeightGSet.LinkedElement next) {
this.nextLinkedElement = next;
}
/* UnderConstruction Feature related */
public BlockUnderConstructionFeature getUnderConstructionFeature() {
return uc;
}
public BlockUCState getBlockUCState() {
return uc == null ? BlockUCState.COMPLETE : uc.getBlockUCState();
}
/**
* Is this block complete?
*
* @return true if the state of the block is {@link BlockUCState#COMPLETE}
*/
public boolean isComplete() {
return getBlockUCState().equals(BlockUCState.COMPLETE);
}
public boolean isUnderRecovery() {
return getBlockUCState().equals(BlockUCState.UNDER_RECOVERY);
}
public final boolean isCompleteOrCommitted() {
final BlockUCState state = getBlockUCState();
return state.equals(BlockUCState.COMPLETE) ||
state.equals(BlockUCState.COMMITTED);
}
/**
* Add/Update the under construction feature.
*/
public void convertToBlockUnderConstruction(BlockUCState s,
DatanodeStorageInfo[] targets) {
if (isComplete()) {
uc = new BlockUnderConstructionFeature(this, s, targets,
this.getBlockType());
} else {
// the block is already under construction
uc.setBlockUCState(s);
uc.setExpectedLocations(this, targets, this.getBlockType());
}
}
/**
* Convert an under construction block to complete.
*/
void convertToCompleteBlock() {
assert getBlockUCState() != BlockUCState.COMPLETE :
"Trying to convert a COMPLETE block";
uc = null;
}
/**
* Process the recorded replicas. When about to commit or finish the
* pipeline recovery sort out bad replicas.
* @param genStamp The final generation stamp for the block.
* @return staleReplica's List.
*/
public List setGenerationStampAndVerifyReplicas(
long genStamp) {
Preconditions.checkState(uc != null && !isComplete());
// Set the generation stamp for the block.
setGenerationStamp(genStamp);
return uc.getStaleReplicas(genStamp);
}
/**
* Commit block's length and generation stamp as reported by the client.
* Set block state to {@link BlockUCState#COMMITTED}.
* @param block - contains client reported block length and generation
* @return staleReplica's List.
* @throws IOException if block ids are inconsistent.
*/
List commitBlock(Block block) throws IOException {
if (getBlockId() != block.getBlockId()) {
throw new IOException("Trying to commit inconsistent block: id = "
+ block.getBlockId() + ", expected id = " + getBlockId());
}
Preconditions.checkState(!isComplete());
uc.commit();
this.setNumBytes(block.getNumBytes());
// Sort out invalid replicas.
return setGenerationStampAndVerifyReplicas(block.getGenerationStamp());
}
}
