* @ingroup LockManager
* @since 1.19
*/
-class LSLockManager extends LockManager {
+class LSLockManager extends QuorumLockManager {
/** @var Array Mapping of lock types to the type actually used */
protected $lockTypeMap = array(
self::LOCK_SH => self::LOCK_SH,
/** @var Array Map of server names to server config */
protected $lockServers; // (server name => server config array)
- /** @var Array Map of bucket indexes to peer server lists */
- protected $srvsByBucket; // (bucket index => (lsrv1, lsrv2, ...))
/** @var Array Map Server connections (server name => resource) */
protected $conns = array();
/**
* Construct a new instance from configuration.
- *
+ *
* $config paramaters include:
* 'lockServers' : Associative array of server names to configuration.
* Configuration is an associative array that includes:
* each having an odd-numbered list of server names (peers) as values.
* 'connTimeout' : Lock server connection attempt timeout. [optional]
*
- * @param Array $config
+ * @param Array $config
*/
public function __construct( array $config ) {
parent::__construct( $config );
$this->connTimeout = 3; // use some sane amount
}
- $this->session = '';
- for ( $i = 0; $i < 5; $i++ ) {
- $this->session .= mt_rand( 0, 2147483647 );
- }
- $this->session = wfBaseConvert( sha1( $this->session ), 16, 36, 31 );
+ $this->session = wfRandomString( 31 );
}
/**
- * @see LockManager::doLock()
- * @param $paths array
- * @param $type int
+ * @see QuorumLockManager::getLocksOnServer()
* @return Status
*/
- protected function doLock( array $paths, $type ) {
+ protected function getLocksOnServer( $lockSrv, array $paths, $type ) {
$status = Status::newGood();
- $pathsToLock = array();
- // Get locks that need to be acquired (buckets => locks)...
- foreach ( $paths as $path ) {
- if ( isset( $this->locksHeld[$path][$type] ) ) {
- ++$this->locksHeld[$path][$type];
- } elseif ( isset( $this->locksHeld[$path][self::LOCK_EX] ) ) {
- $this->locksHeld[$path][$type] = 1;
- } else {
- $bucket = $this->getBucketFromKey( $path );
- $pathsToLock[$bucket][] = $path;
- }
- }
+ // Send out the command and get the response...
+ $type = ( $type == self::LOCK_SH ) ? 'SH' : 'EX';
+ $keys = array_unique( array_map( 'LockManager::sha1Base36', $paths ) );
+ $response = $this->sendCommand( $lockSrv, 'ACQUIRE', $type, $keys );
- $lockedPaths = array(); // files locked in this attempt
- // Attempt to acquire these locks...
- foreach ( $pathsToLock as $bucket => $paths ) {
- // Try to acquire the locks for this bucket
- $res = $this->doLockingRequestAll( $bucket, $paths, $type );
- if ( $res === 'cantacquire' ) {
- // Resources already locked by another process.
- // Abort and unlock everything we just locked.
- foreach ( $paths as $path ) {
- $status->fatal( 'lockmanager-fail-acquirelock', $path );
- }
- $status->merge( $this->doUnlock( $lockedPaths, $type ) );
- return $status;
- } elseif ( $res !== true ) {
- // Couldn't contact any servers for this bucket.
- // Abort and unlock everything we just locked.
- foreach ( $paths as $path ) {
- $status->fatal( 'lockmanager-fail-acquirelock', $path );
- }
- $status->merge( $this->doUnlock( $lockedPaths, $type ) );
- return $status;
- }
- // Record these locks as active
+ if ( $response !== 'ACQUIRED' ) {
foreach ( $paths as $path ) {
- $this->locksHeld[$path][$type] = 1; // locked
+ $status->fatal( 'lockmanager-fail-acquirelock', $path );
}
- // Keep track of what locks were made in this attempt
- $lockedPaths = array_merge( $lockedPaths, $paths );
}
return $status;
}
/**
- * @see LockManager::doUnlock()
- * @param $paths array
- * @param $type int
+ * @see QuorumLockManager::freeLocksOnServer()
* @return Status
*/
- protected function doUnlock( array $paths, $type ) {
+ protected function freeLocksOnServer( $lockSrv, array $paths, $type ) {
$status = Status::newGood();
- foreach ( $paths as $path ) {
- if ( !isset( $this->locksHeld[$path] ) ) {
- $status->warning( 'lockmanager-notlocked', $path );
- } elseif ( !isset( $this->locksHeld[$path][$type] ) ) {
- $status->warning( 'lockmanager-notlocked', $path );
- } else {
- --$this->locksHeld[$path][$type];
- if ( $this->locksHeld[$path][$type] <= 0 ) {
- unset( $this->locksHeld[$path][$type] );
- }
- if ( !count( $this->locksHeld[$path] ) ) {
- unset( $this->locksHeld[$path] ); // no SH or EX locks left for key
- }
- }
- }
+ // Send out the command and get the response...
+ $type = ( $type == self::LOCK_SH ) ? 'SH' : 'EX';
+ $keys = array_unique( array_map( 'LockManager::sha1Base36', $paths ) );
+ $response = $this->sendCommand( $lockSrv, 'RELEASE', $type, $keys );
- // Reference count the locks held and release locks when zero
- if ( !count( $this->locksHeld ) ) {
- $status->merge( $this->releaseLocks() );
+ if ( $response !== 'RELEASED' ) {
+ foreach ( $paths as $path ) {
+ $status->fatal( 'lockmanager-fail-releaselock', $path );
+ }
}
return $status;
}
/**
- * Get a connection to a lock server and acquire locks on $paths
- *
- * @param $lockSrv string
- * @param $paths Array
- * @param $type integer LockManager::LOCK_EX or LockManager::LOCK_SH
- * @return bool Resources able to be locked
+ * @see QuorumLockManager::releaseAllLocks()
+ * @return Status
*/
- protected function doLockingRequest( $lockSrv, array $paths, $type ) {
- if ( $type == self::LOCK_SH ) { // reader locks
- $type = 'SH';
- } elseif ( $type == self::LOCK_EX ) { // writer locks
- $type = 'EX';
- } else {
- return true; // ok...
+ protected function releaseAllLocks() {
+ $status = Status::newGood();
+
+ foreach ( $this->conns as $lockSrv => $conn ) {
+ $response = $this->sendCommand( $lockSrv, 'RELEASE_ALL', '', array() );
+ if ( $response !== 'RELEASED_ALL' ) {
+ $status->fatal( 'lockmanager-fail-svr-release', $lockSrv );
+ }
}
- // Send out the command and get the response...
- $keys = array_unique( array_map( 'LockManager::sha1Base36', $paths ) );
- $response = $this->sendCommand( $lockSrv, 'ACQUIRE', $type, $keys );
+ return $status;
+ }
- return ( $response === 'ACQUIRED' );
+ /**
+ * @see QuorumLockManager::isServerUp()
+ * @return bool
+ */
+ protected function isServerUp( $lockSrv ) {
+ return (bool)$this->getConnection( $lockSrv );
}
/**
return trim( $response );
}
- /**
- * Attempt to acquire locks with the peers for a bucket
- *
- * @param $bucket integer
- * @param $paths Array List of resource keys to lock
- * @param $type integer LockManager::LOCK_EX or LockManager::LOCK_SH
- * @return bool|string One of (true, 'cantacquire', 'srverrors')
- */
- protected function doLockingRequestAll( $bucket, array $paths, $type ) {
- $yesVotes = 0; // locks made on trustable servers
- $votesLeft = count( $this->srvsByBucket[$bucket] ); // remaining peers
- $quorum = floor( $votesLeft/2 + 1 ); // simple majority
- // Get votes for each peer, in order, until we have enough...
- foreach ( $this->srvsByBucket[$bucket] as $lockSrv ) {
- // Attempt to acquire the lock on this peer
- if ( !$this->doLockingRequest( $lockSrv, $paths, $type ) ) {
- return 'cantacquire'; // vetoed; resource locked
- }
- ++$yesVotes; // success for this peer
- if ( $yesVotes >= $quorum ) {
- return true; // lock obtained
- }
- --$votesLeft;
- $votesNeeded = $quorum - $yesVotes;
- if ( $votesNeeded > $votesLeft ) {
- // In "trust cache" mode we don't have to meet the quorum
- break; // short-circuit
- }
- }
- // At this point, we must not have meet the quorum
- return 'srverrors'; // not enough votes to ensure correctness
- }
-
/**
* Get (or reuse) a connection to a lock server
*
return $this->conns[$lockSrv];
}
- /**
- * Release all locks that this session is holding
- *
- * @return Status
- */
- protected function releaseLocks() {
- $status = Status::newGood();
- foreach ( $this->conns as $lockSrv => $conn ) {
- $response = $this->sendCommand( $lockSrv, 'RELEASE_ALL', '', array() );
- if ( $response !== 'RELEASED_ALL' ) {
- $status->fatal( 'lockmanager-fail-svr-release', $lockSrv );
- }
- }
- return $status;
- }
-
- /**
- * Get the bucket for resource path.
- * This should avoid throwing any exceptions.
- *
- * @param $path string
- * @return integer
- */
- protected function getBucketFromKey( $path ) {
- $prefix = substr( sha1( $path ), 0, 2 ); // first 2 hex chars (8 bits)
- return intval( base_convert( $prefix, 16, 10 ) ) % count( $this->srvsByBucket );
- }
-
/**
* Make sure remaining locks get cleared for sanity
*/
function __destruct() {
- $this->releaseLocks();
+ $this->releaseAllLocks();
foreach ( $this->conns as $conn ) {
fclose( $conn );
}
/**
* Lock the resources at the given abstract paths
- *
+ *
* @param $paths Array List of resource names
* @param $type integer LockManager::LOCK_* constant
- * @return Status
+ * @return Status
*/
final public function lock( array $paths, $type = self::LOCK_EX ) {
wfProfileIn( __METHOD__ );
/**
* Unlock the resources at the given abstract paths
- *
+ *
* @param $paths Array List of storage paths
* @param $type integer LockManager::LOCK_* constant
- * @return Status
+ * @return Status
*/
final public function unlock( array $paths, $type = self::LOCK_EX ) {
wfProfileIn( __METHOD__ );
/**
* Get the base 36 SHA-1 of a string, padded to 31 digits
- *
+ *
* @param $path string
* @return string
*/
/**
* Lock resources with the given keys and lock type
- *
+ *
* @param $paths Array List of storage paths
* @param $type integer LockManager::LOCK_* constant
* @return string
/**
* Unlock resources with the given keys and lock type
- *
+ *
* @param $paths Array List of storage paths
* @param $type integer LockManager::LOCK_* constant
* @return string
}
/**
- * Self releasing locks
+ * Self-releasing locks
*
* LockManager helper class to handle scoped locks, which
* release when an object is destroyed or goes out of scope.
* Get a ScopedLock object representing a lock on resource paths.
* Any locks are released once this object goes out of scope.
* The status object is updated with any errors or warnings.
- *
+ *
* @param $manager LockManager
* @param $paths Array List of storage paths
* @param $type integer LockManager::LOCK_* constant
}
}
+/**
+ * Version of LockManager that uses a quorum from peer servers for locks.
+ * The resource space can also be sharded into separate peer groups.
+ *
+ * @ingroup LockManager
+ * @since 1.20
+ */
+abstract class QuorumLockManager extends LockManager {
+ /** @var Array Map of bucket indexes to peer server lists */
+ protected $srvsByBucket = array(); // (bucket index => (lsrv1, lsrv2, ...))
+
+ /**
+ * @see LockManager::doLock()
+ * @param $paths array
+ * @param $type int
+ * @return Status
+ */
+ final protected function doLock( array $paths, $type ) {
+ $status = Status::newGood();
+
+ $pathsToLock = array(); // (bucket => paths)
+ // Get locks that need to be acquired (buckets => locks)...
+ foreach ( $paths as $path ) {
+ if ( isset( $this->locksHeld[$path][$type] ) ) {
+ ++$this->locksHeld[$path][$type];
+ } elseif ( isset( $this->locksHeld[$path][self::LOCK_EX] ) ) {
+ $this->locksHeld[$path][$type] = 1;
+ } else {
+ $bucket = $this->getBucketFromKey( $path );
+ $pathsToLock[$bucket][] = $path;
+ }
+ }
+
+ $lockedPaths = array(); // files locked in this attempt
+ // Attempt to acquire these locks...
+ foreach ( $pathsToLock as $bucket => $paths ) {
+ // Try to acquire the locks for this bucket
+ $status->merge( $this->doLockingRequestBucket( $bucket, $paths, $type ) );
+ if ( !$status->isOK() ) {
+ $status->merge( $this->doUnlock( $lockedPaths, $type ) );
+ return $status;
+ }
+ // Record these locks as active
+ foreach ( $paths as $path ) {
+ $this->locksHeld[$path][$type] = 1; // locked
+ }
+ // Keep track of what locks were made in this attempt
+ $lockedPaths = array_merge( $lockedPaths, $paths );
+ }
+
+ return $status;
+ }
+
+ /**
+ * @see LockManager::doUnlock()
+ * @param $paths array
+ * @param $type int
+ * @return Status
+ */
+ final protected function doUnlock( array $paths, $type ) {
+ $status = Status::newGood();
+
+ $pathsToUnlock = array();
+ foreach ( $paths as $path ) {
+ if ( !isset( $this->locksHeld[$path][$type] ) ) {
+ $status->warning( 'lockmanager-notlocked', $path );
+ } else {
+ --$this->locksHeld[$path][$type];
+ // Reference count the locks held and release locks when zero
+ if ( $this->locksHeld[$path][$type] <= 0 ) {
+ unset( $this->locksHeld[$path][$type] );
+ $bucket = $this->getBucketFromKey( $path );
+ $pathsToUnlock[$bucket][] = $path;
+ }
+ if ( !count( $this->locksHeld[$path] ) ) {
+ unset( $this->locksHeld[$path] ); // no SH or EX locks left for key
+ }
+ }
+ }
+
+ // Remove these single locks if the medium supports it
+ foreach ( $pathsToUnlock as $bucket => $paths ) {
+ $status->merge( $this->doUnlockingRequestBucket( $bucket, $paths, $type ) );
+ }
+
+ // Reference count the locks held and release locks when zero
+ if ( !count( $this->locksHeld ) ) {
+ $status->merge( $this->releaseAllLocks() );
+ }
+
+ return $status;
+ }
+
+ /**
+ * Attempt to acquire locks with the peers for a bucket.
+ * This is all or nothing; if any key is locked then this totally fails.
+ *
+ * @param $bucket integer
+ * @param $paths Array List of resource keys to lock
+ * @param $type integer LockManager::LOCK_EX or LockManager::LOCK_SH
+ * @return Status
+ */
+ final protected function doLockingRequestBucket( $bucket, array $paths, $type ) {
+ $status = Status::newGood();
+
+ $yesVotes = 0; // locks made on trustable servers
+ $votesLeft = count( $this->srvsByBucket[$bucket] ); // remaining peers
+ $quorum = floor( $votesLeft/2 + 1 ); // simple majority
+ // Get votes for each peer, in order, until we have enough...
+ foreach ( $this->srvsByBucket[$bucket] as $lockSrv ) {
+ if ( !$this->isServerUp( $lockSrv ) ) {
+ --$votesLeft;
+ $status->warning( 'lockmanager-fail-svr-acquire', $lockSrv );
+ continue; // server down?
+ }
+ // Attempt to acquire the lock on this peer
+ $status->merge( $this->getLocksOnServer( $lockSrv, $paths, $type ) );
+ if ( !$status->isOK() ) {
+ return $status; // vetoed; resource locked
+ }
+ ++$yesVotes; // success for this peer
+ if ( $yesVotes >= $quorum ) {
+ return $status; // lock obtained
+ }
+ --$votesLeft;
+ $votesNeeded = $quorum - $yesVotes;
+ if ( $votesNeeded > $votesLeft ) {
+ break; // short-circuit
+ }
+ }
+ // At this point, we must not have met the quorum
+ $status->setResult( false );
+
+ return $status;
+ }
+
+ /**
+ * Attempt to release locks with the peers for a bucket
+ *
+ * @param $bucket integer
+ * @param $paths Array List of resource keys to lock
+ * @param $type integer LockManager::LOCK_EX or LockManager::LOCK_SH
+ * @return Status
+ */
+ final protected function doUnlockingRequestBucket( $bucket, array $paths, $type ) {
+ $status = Status::newGood();
+
+ foreach ( $this->srvsByBucket[$bucket] as $lockSrv ) {
+ if ( !$this->isServerUp( $lockSrv ) ) {
+ $status->fatal( 'lockmanager-fail-svr-release', $lockSrv );
+ // Attempt to release the lock on this peer
+ } else {
+ $status->merge( $this->freeLocksOnServer( $lockSrv, $paths, $type ) );
+ }
+ }
+
+ return $status;
+ }
+
+ /**
+ * Get the bucket for resource path.
+ * This should avoid throwing any exceptions.
+ *
+ * @param $path string
+ * @return integer
+ */
+ protected function getBucketFromKey( $path ) {
+ $prefix = substr( sha1( $path ), 0, 2 ); // first 2 hex chars (8 bits)
+ return (int)base_convert( $prefix, 16, 10 ) % count( $this->srvsByBucket );
+ }
+
+ /**
+ * Check if a lock server is up
+ *
+ * @param $lockSrv string
+ * @return bool
+ */
+ abstract protected function isServerUp( $lockSrv );
+
+ /**
+ * Get a connection to a lock server and acquire locks on $paths
+ *
+ * @param $lockSrv string
+ * @param $paths array
+ * @param $type integer
+ * @return Status
+ */
+ abstract protected function getLocksOnServer( $lockSrv, array $paths, $type );
+
+ /**
+ * Get a connection to a lock server and release locks on $paths
+ *
+ * @param $lockSrv string
+ * @param $paths array
+ * @param $type integer
+ * @return Status
+ */
+ abstract protected function freeLocksOnServer( $lockSrv, array $paths, $type );
+
+ /**
+ * Release all locks that this session is holding
+ *
+ * @return Status
+ */
+ abstract protected function releaseAllLocks();
+}
+
/**
* Simple version of LockManager that does nothing
* @since 1.19
dépôts / lhc / web / wiklou.git / commitdiff