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HDDS-475. Block Allocation returns same BlockID on different keys creation.

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Contributed by Nanda Kumar.
This commit is contained in:
Anu Engineer 2018-09-17 14:08:39 -07:00
parent 26d0c63a1e
commit 23a6137a40
1 changed files with 118 additions and 86 deletions
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68
hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/block/BlockManagerImpl.java
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@ -48,8 +48,6 @@
import java.util.Map;
import java.util.Random;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import static org.apache.hadoop.hdds.scm.exceptions.SCMException.ResultCodes
.CHILL_MODE_EXCEPTION;
@ -76,7 +74,6 @@ public class BlockManagerImpl implements EventHandler<Boolean>,
private final NodeManager nodeManager;
private final Mapping containerManager;
private final ReadWriteLock lock;
private final long containerSize;
private final DeletedBlockLog deletedBlockLog;
@ -113,7 +110,6 @@ public BlockManagerImpl(final Configuration conf,
ScmConfigKeys.OZONE_SCM_CONTAINER_PROVISION_BATCH_SIZE,
ScmConfigKeys.OZONE_SCM_CONTAINER_PROVISION_BATCH_SIZE_DEFAULT);
rand = new Random();
this.lock = new ReentrantReadWriteLock();
mxBean = MBeans.register("BlockManager", "BlockManagerImpl", this);
@ -223,8 +219,6 @@ public AllocatedBlock allocateBlock(final long size,
ContainerWithPipeline containerWithPipeline;
lock.readLock().lock();
try {
// This is to optimize performance, if the below condition is evaluated
// to false, then we can be sure that there are no containers in
// ALLOCATED state.
@ -302,16 +296,9 @@ public AllocatedBlock allocateBlock(final long size,
// we have tried all strategies we know and but somehow we are not able
// to get a container for this block. Log that info and return a null.
LOG.error(
"Unable to allocate a block for the size: {}, type: {}, " +
"factor: {}",
size,
type,
factor);
"Unable to allocate a block for the size: {}, type: {}, factor: {}",
size, type, factor);
return null;
} finally {
lock.readLock().unlock();
}
}
/**
@ -330,9 +317,7 @@ private AllocatedBlock newBlock(ContainerWithPipeline containerWithPipeline,
}
// TODO : Revisit this local ID allocation when HA is added.
// TODO: this does not work well if multiple allocation kicks in a tight
// loop.
long localID = Time.getUtcTime();
long localID = UniqueId.next();
long containerID = containerInfo.getContainerID();
boolean createContainer = (state == HddsProtos.LifeCycleState.ALLOCATED);
@ -463,4 +448,51 @@ public boolean isScmInChillMode() {
public static Logger getLogger() {
return LOG;
}
/**
* This class uses system current time milliseconds to generate unique id.
*/
public static final class UniqueId {
/*
* When we represent time in milliseconds using 'long' data type,
* the LSB bits are used. Currently we are only using 44 bits (LSB),
* 20 bits (MSB) are not used.
* We will exhaust this 44 bits only when we are in year 2525,
* until then we can safely use this 20 bits (MSB) for offset to generate
* unique id within millisecond.
*
* Year : Mon Dec 31 18:49:04 IST 2525
* TimeInMillis: 17545641544247
* Binary Representation:
* MSB (20 bits): 0000 0000 0000 0000 0000
* LSB (44 bits): 1111 1111 0101 0010 1001 1011 1011 0100 1010 0011 0111
*
* We have 20 bits to run counter, we should exclude the first bit (MSB)
* as we don't want to deal with negative values.
* To be on safer side we will use 'short' data type which is of length
* 16 bits and will give us 65,536 values for offset.
*
*/
private static volatile short offset = 0;
/**
* Private constructor so that no one can instantiate this class.
*/
private UniqueId() {}
/**
* Calculate and returns next unique id based on System#currentTimeMillis.
*
* @return unique long value
*/
public static synchronized long next() {
long utcTime = Time.getUtcTime();
if ((utcTime & 0xFFFF000000000000L) == 0) {
return utcTime << Short.SIZE | (offset++ & 0x0000FFFF);
}
throw new RuntimeException("Got invalid UTC time," +
" cannot generate unique Id. UTC Time: " + utcTime);
}
}
}