diff options
Diffstat (limited to 'includes/filebackend/lockmanager/LockManager.php')
| -rw-r--r-- | includes/filebackend/lockmanager/LockManager.php | 324 |
1 files changed, 40 insertions, 284 deletions
diff --git a/includes/filebackend/lockmanager/LockManager.php b/includes/filebackend/lockmanager/LockManager.php index 07853f87..0512a01b 100644 --- a/includes/filebackend/lockmanager/LockManager.php +++ b/includes/filebackend/lockmanager/LockManager.php @@ -53,6 +53,9 @@ abstract class LockManager { /** @var Array Map of (resource path => lock type => count) */ protected $locksHeld = array(); + protected $domain; // string; domain (usually wiki ID) + protected $lockTTL; // integer; maximum time locks can be held + /* Lock types; stronger locks have higher values */ const LOCK_SH = 1; // shared lock (for reads) const LOCK_UW = 2; // shared lock (for reads used to write elsewhere) @@ -61,14 +64,29 @@ abstract class LockManager { /** * Construct a new instance from configuration * + * $config paramaters include: + * - domain : Domain (usually wiki ID) that all resources are relative to [optional] + * - lockTTL : Age (in seconds) at which resource locks should expire. + * This only applies if locks are not tied to a connection/process. + * * @param $config Array */ - public function __construct( array $config ) {} + public function __construct( array $config ) { + $this->domain = isset( $config['domain'] ) ? $config['domain'] : wfWikiID(); + if ( isset( $config['lockTTL'] ) ) { + $this->lockTTL = max( 1, $config['lockTTL'] ); + } elseif ( PHP_SAPI === 'cli' ) { + $this->lockTTL = 2*3600; + } else { + $met = ini_get( 'max_execution_time' ); // this is 0 in CLI mode + $this->lockTTL = max( 5*60, 2*(int)$met ); + } + } /** * Lock the resources at the given abstract paths * - * @param $paths Array List of resource names + * @param array $paths List of resource names * @param $type integer LockManager::LOCK_* constant * @return Status */ @@ -82,7 +100,7 @@ abstract class LockManager { /** * Unlock the resources at the given abstract paths * - * @param $paths Array List of storage paths + * @param array $paths List of storage paths * @param $type integer LockManager::LOCK_* constant * @return Status */ @@ -94,308 +112,46 @@ abstract class LockManager { } /** - * Get the base 36 SHA-1 of a string, padded to 31 digits + * Get the base 36 SHA-1 of a string, padded to 31 digits. + * Before hashing, the path will be prefixed with the domain ID. + * This should be used interally for lock key or file names. * * @param $path string * @return string */ - final protected static function sha1Base36( $path ) { - return wfBaseConvert( sha1( $path ), 16, 36, 31 ); + final protected function sha1Base36Absolute( $path ) { + return wfBaseConvert( sha1( "{$this->domain}:{$path}" ), 16, 36, 31 ); } /** - * Lock resources with the given keys and lock type + * Get the base 16 SHA-1 of a string, padded to 31 digits. + * Before hashing, the path will be prefixed with the domain ID. + * This should be used interally for lock key or file names. * - * @param $paths Array List of storage paths - * @param $type integer LockManager::LOCK_* constant + * @param $path string * @return string */ - abstract protected function doLock( array $paths, $type ); + final protected function sha1Base16Absolute( $path ) { + return sha1( "{$this->domain}:{$path}" ); + } /** - * Unlock resources with the given keys and lock type + * Lock resources with the given keys and lock type * - * @param $paths Array List of storage paths + * @param array $paths List of storage paths * @param $type integer LockManager::LOCK_* constant * @return string */ - abstract protected function doUnlock( array $paths, $type ); -} - -/** - * Self-releasing locks - * - * LockManager helper class to handle scoped locks, which - * release when an object is destroyed or goes out of scope. - * - * @ingroup LockManager - * @since 1.19 - */ -class ScopedLock { - /** @var LockManager */ - protected $manager; - /** @var Status */ - protected $status; - /** @var Array List of resource paths*/ - protected $paths; - - protected $type; // integer lock type - - /** - * @param $manager LockManager - * @param $paths Array List of storage paths - * @param $type integer LockManager::LOCK_* constant - * @param $status Status - */ - protected function __construct( - LockManager $manager, array $paths, $type, Status $status - ) { - $this->manager = $manager; - $this->paths = $paths; - $this->status = $status; - $this->type = $type; - } + abstract protected function doLock( array $paths, $type ); /** - * 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. + * Unlock resources with the given keys and lock type * - * @param $manager LockManager - * @param $paths Array List of storage paths + * @param array $paths List of storage paths * @param $type integer LockManager::LOCK_* constant - * @param $status Status - * @return ScopedLock|null Returns null on failure - */ - public static function factory( - LockManager $manager, array $paths, $type, Status $status - ) { - $lockStatus = $manager->lock( $paths, $type ); - $status->merge( $lockStatus ); - if ( $lockStatus->isOK() ) { - return new self( $manager, $paths, $type, $status ); - } - return null; - } - - function __destruct() { - $wasOk = $this->status->isOK(); - $this->status->merge( $this->manager->unlock( $this->paths, $this->type ) ); - if ( $wasOk ) { - // Make sure status is OK, despite any unlockFiles() fatals - $this->status->setResult( true, $this->status->value ); - } - } -} - -/** - * 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 specific locks if possible, or at least release - // all locks once this process is currently not holding any locks. - foreach ( $pathsToUnlock as $bucket => $paths ) { - $status->merge( $this->doUnlockingRequestBucket( $bucket, $paths, $type ) ); - } - 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. - * - * Subclasses must effectively implement this or releaseAllLocks(). - * - * @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. - * - * Subclasses must effectively implement this or freeLocksOnServer(). - * - * @return Status + * @return string */ - abstract protected function releaseAllLocks(); + abstract protected function doUnlock( array $paths, $type ); } /** |