org.apache.hadoop.hdfs.server.blockmanagement

Class BlockIdManager

java.lang.Object

org.apache.hadoop.hdfs.server.blockmanagement.BlockIdManager

public class BlockIdManager
extends Object

BlockIdManager allocates the generation stamps and the block ID. The FSNamesystem is responsible for persisting the allocations in the EditLog.

Constructor Summary

Constructors

Constructor and Description
BlockIdManager(org.apache.hadoop.hdfs.server.blockmanagement.BlockManager blockManager)

Method Summary

Methods

Modifier and Type	Method and Description
void	clear()
long	getGenerationStampAtblockIdSwitch() Gets the value of the generation stamp that delineates sequential and random block IDs.
long	getGenerationStampV1() Gets the current generation stamp for legacy blocks
long	getGenerationStampV1Limit()
long	getGenerationStampV2()
long	getLastAllocatedBlockId() Gets the maximum sequentially allocated block ID for this filesystem
boolean	isGenStampInFuture(org.apache.hadoop.hdfs.protocol.Block block)
boolean	isLegacyBlock(org.apache.hadoop.hdfs.protocol.Block block) Determine whether the block ID was randomly generated (legacy) or sequentially generated.
long	nextBlockId() Increments, logs and then returns the block ID
long	nextGenerationStamp(boolean legacyBlock) Increments, logs and then returns the stamp
void	setGenerationStampV1(long stamp) Sets the current generation stamp for legacy blocks
void	setGenerationStampV1Limit(long stamp) Sets the generation stamp that delineates random and sequentially allocated block IDs.
void	setGenerationStampV2(long stamp) Gets the current generation stamp for this filesystem
void	setLastAllocatedBlockId(long blockId) Sets the maximum allocated block ID for this filesystem.
long	upgradeGenerationStampToV2() Upgrades the generation stamp for the filesystem by reserving a sufficient range for all existing blocks.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BlockIdManager

public BlockIdManager(org.apache.hadoop.hdfs.server.blockmanagement.BlockManager blockManager)

Method Detail

upgradeGenerationStampToV2

public long upgradeGenerationStampToV2()

Upgrades the generation stamp for the filesystem by reserving a sufficient range for all existing blocks. Should be invoked only during the first upgrade to sequential block IDs.

setGenerationStampV1Limit

public void setGenerationStampV1Limit(long stamp)

Sets the generation stamp that delineates random and sequentially allocated block IDs.

Parameters:

stamp - set generation stamp limit to this value

getGenerationStampAtblockIdSwitch

public long getGenerationStampAtblockIdSwitch()

Gets the value of the generation stamp that delineates sequential and random block IDs.

setLastAllocatedBlockId

public void setLastAllocatedBlockId(long blockId)

Sets the maximum allocated block ID for this filesystem. This is the basis for allocating new block IDs.

getLastAllocatedBlockId

public long getLastAllocatedBlockId()

Gets the maximum sequentially allocated block ID for this filesystem

setGenerationStampV1

public void setGenerationStampV1(long stamp)

Sets the current generation stamp for legacy blocks

getGenerationStampV1

public long getGenerationStampV1()

Gets the current generation stamp for legacy blocks

setGenerationStampV2

public void setGenerationStampV2(long stamp)

Gets the current generation stamp for this filesystem

getGenerationStampV2

public long getGenerationStampV2()

nextGenerationStamp

public long nextGenerationStamp(boolean legacyBlock)
                         throws IOException

Increments, logs and then returns the stamp

Throws:

IOException

getGenerationStampV1Limit

public long getGenerationStampV1Limit()

isLegacyBlock

public boolean isLegacyBlock(org.apache.hadoop.hdfs.protocol.Block block)

Determine whether the block ID was randomly generated (legacy) or sequentially generated. The generation stamp value is used to make the distinction.

Returns:

true if the block ID was randomly generated, false otherwise.

nextBlockId

public long nextBlockId()

Increments, logs and then returns the block ID

isGenStampInFuture

public boolean isGenStampInFuture(org.apache.hadoop.hdfs.protocol.Block block)

clear

public void clear()