includes/filebackend/FileBackendMultiWrite.php

   1 <?php
   2 /**
   3  * Proxy backend that mirrors writes to several internal backends.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup FileBackend
  22  * @author Aaron Schulz
  23  */
  24
  25 /**
  26  * @brief Proxy backend that mirrors writes to several internal backends.
  27  *
  28  * This class defines a multi-write backend. Multiple backends can be
  29  * registered to this proxy backend and it will act as a single backend.
  30  * Use this when all access to those backends is through this proxy backend.
  31  * At least one of the backends must be declared the "master" backend.
  32  *
  33  * Only use this class when transitioning from one storage system to another.
  34  *
  35  * Read operations are only done on the 'master' backend for consistency.
  36  * Write operations are performed on all backends, in the order defined.
  37  * If an operation fails on one backend it will be rolled back from the others.
  38  *
  39  * @ingroup FileBackend
  40  * @since 1.19
  41  */
  42 class FileBackendMultiWrite extends FileBackend {
  43         /** @var Array Prioritized list of FileBackendStore objects */
  44         protected $backends = array(); // array of (backend index => backends)
  45         protected $masterIndex = -1; // integer; index of master backend
  46         protected $syncChecks = 0; // integer; bitfield
  47         protected $autoResync = false; // boolean
  48
  49         /** @var Array */
  50         protected $noPushDirConts = array();
  51         protected $noPushQuickOps = false; // boolean
  52
  53         /* Possible internal backend consistency checks */
  54         const CHECK_SIZE = 1;
  55         const CHECK_TIME = 2;
  56         const CHECK_SHA1 = 4;
  57
  58         /**
  59          * Construct a proxy backend that consists of several internal backends.
  60          * Locking, journaling, and read-only checks are handled by the proxy backend.
  61          *
  62          * Additional $config params include:
  63          *   - backends       : Array of backend config and multi-backend settings.
  64          *                      Each value is the config used in the constructor of a
  65          *                      FileBackendStore class, but with these additional settings:
  66          *                        - class         : The name of the backend class
  67          *                        - isMultiMaster : This must be set for one backend.
  68          *                        - template:     : If given a backend name, this will use
  69          *                                          the config of that backend as a template.
  70          *                                          Values specified here take precedence.
  71          *   - syncChecks     : Integer bitfield of internal backend sync checks to perform.
  72          *                      Possible bits include the FileBackendMultiWrite::CHECK_* constants.
  73          *                      There are constants for SIZE, TIME, and SHA1.
  74          *                      The checks are done before allowing any file operations.
  75          *   - autoResync     : Automatically resync the clone backends to the master backend
  76          *                      when pre-operation sync checks fail. This should only be used
  77          *                      if the master backend is stable and not missing any files.
  78          *                      Use "conservative" to limit resyncing to copying newer master
  79          *                      backend files over older (or non-existing) clone backend files.
  80          *                      Cases that cannot be handled will result in operation abortion.
  81          *   - noPushQuickOps : (hack) Only apply doQuickOperations() to the master backend.
  82          *   - noPushDirConts : (hack) Only apply directory functions to the master backend.
  83          *
  84          * @param Array $config
  85          * @throws MWException
  86          */
  87         public function __construct( array $config ) {
  88                 parent::__construct( $config );
  89                 $this->syncChecks = isset( $config['syncChecks'] )
  90                         ? $config['syncChecks']
  91                         : self::CHECK_SIZE;
  92                 $this->autoResync = isset( $config['autoResync'] )
  93                         ? $config['autoResync']
  94                         : false;
  95                 $this->noPushQuickOps = isset( $config['noPushQuickOps'] )
  96                         ? $config['noPushQuickOps']
  97                         : false;
  98                 $this->noPushDirConts = isset( $config['noPushDirConts'] )
  99                         ? $config['noPushDirConts']
 100                         : array();
 101                 // Construct backends here rather than via registration
 102                 // to keep these backends hidden from outside the proxy.
 103                 $namesUsed = array();
 104                 foreach ( $config['backends'] as $index => $config ) {
 105                         if ( isset( $config['template'] ) ) {
 106                                 // Config is just a modified version of a registered backend's.
 107                                 // This should only be used when that config is used only by this backend.
 108                                 $config = $config + FileBackendGroup::singleton()->config( $config['template'] );
 109                         }
 110                         $name = $config['name'];
 111                         if ( isset( $namesUsed[$name] ) ) { // don't break FileOp predicates
 112                                 throw new MWException( "Two or more backends defined with the name $name." );
 113                         }
 114                         $namesUsed[$name] = 1;
 115                         // Alter certain sub-backend settings for sanity
 116                         unset( $config['readOnly'] ); // use proxy backend setting
 117                         unset( $config['fileJournal'] ); // use proxy backend journal
 118                         $config['wikiId'] = $this->wikiId; // use the proxy backend wiki ID
 119                         $config['lockManager'] = 'nullLockManager'; // lock under proxy backend
 120                         if ( !empty( $config['isMultiMaster'] ) ) {
 121                                 if ( $this->masterIndex >= 0 ) {
 122                                         throw new MWException( 'More than one master backend defined.' );
 123                                 }
 124                                 $this->masterIndex = $index; // this is the "master"
 125                                 $config['fileJournal'] = $this->fileJournal; // log under proxy backend
 126                         }
 127                         // Create sub-backend object
 128                         if ( !isset( $config['class'] ) ) {
 129                                 throw new MWException( 'No class given for a backend config.' );
 130                         }
 131                         $class = $config['class'];
 132                         $this->backends[$index] = new $class( $config );
 133                 }
 134                 if ( $this->masterIndex < 0 ) { // need backends and must have a master
 135                         throw new MWException( 'No master backend defined.' );
 136                 }
 137         }
 138
 139         final protected function doOperationsInternal( array $ops, array $opts ) {
 140                 $status = Status::newGood();
 141
 142                 $mbe = $this->backends[$this->masterIndex]; // convenience
 143
 144                 // Get the paths to lock from the master backend
 145                 $realOps = $this->substOpBatchPaths( $ops, $mbe );
 146                 $paths = $mbe->getPathsToLockForOpsInternal( $mbe->getOperationsInternal( $realOps ) );
 147                 // Get the paths under the proxy backend's name
 148                 $paths['sh'] = $this->unsubstPaths( $paths['sh'] );
 149                 $paths['ex'] = $this->unsubstPaths( $paths['ex'] );
 150                 // Try to lock those files for the scope of this function...
 151                 if ( empty( $opts['nonLocking'] ) ) {
 152                         // Try to lock those files for the scope of this function...
 153                         $scopeLockS = $this->getScopedFileLocks( $paths['sh'], LockManager::LOCK_UW, $status );
 154                         $scopeLockE = $this->getScopedFileLocks( $paths['ex'], LockManager::LOCK_EX, $status );
 155                         if ( !$status->isOK() ) {
 156                                 return $status; // abort
 157                         }
 158                 }
 159                 // Clear any cache entries (after locks acquired)
 160                 $this->clearCache();
 161                 $opts['preserveCache'] = true; // only locked files are cached
 162                 // Get the list of paths to read/write...
 163                 $relevantPaths = $this->fileStoragePathsForOps( $ops );
 164                 // Check if the paths are valid and accessible on all backends...
 165                 $status->merge( $this->accessibilityCheck( $relevantPaths ) );
 166                 if ( !$status->isOK() ) {
 167                         return $status; // abort
 168                 }
 169                 // Do a consistency check to see if the backends are consistent...
 170                 $syncStatus = $this->consistencyCheck( $relevantPaths );
 171                 if ( !$syncStatus->isOK() ) {
 172                         wfDebugLog( 'FileOperation', get_class( $this ) .
 173                                 " failed sync check: " . FormatJson::encode( $relevantPaths ) );
 174                         // Try to resync the clone backends to the master on the spot...
 175                         if ( !$this->autoResync || !$this->resyncFiles( $relevantPaths )->isOK() ) {
 176                                 $status->merge( $syncStatus );
 177                                 return $status; // abort
 178                         }
 179                 }
 180                 // Actually attempt the operation batch on the master backend...
 181                 $masterStatus = $mbe->doOperations( $realOps, $opts );
 182                 $status->merge( $masterStatus );
 183                 // Propagate the operations to the clone backends if there were no unexpected errors
 184                 // and if there were either no expected errors or if the 'force' option was used.
 185                 // However, if nothing succeeded at all, then don't replicate any of the operations.
 186                 // If $ops only had one operation, this might avoid backend sync inconsistencies.
 187                 if ( $masterStatus->isOK() && $masterStatus->successCount > 0 ) {
 188                         foreach ( $this->backends as $index => $backend ) {
 189                                 if ( $index !== $this->masterIndex ) { // not done already
 190                                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 191                                         $status->merge( $backend->doOperations( $realOps, $opts ) );
 192                                 }
 193                         }
 194                 }
 195                 // Make 'success', 'successCount', and 'failCount' fields reflect
 196                 // the overall operation, rather than all the batches for each backend.
 197                 // Do this by only using success values from the master backend's batch.
 198                 $status->success = $masterStatus->success;
 199                 $status->successCount = $masterStatus->successCount;
 200                 $status->failCount = $masterStatus->failCount;
 201
 202                 return $status;
 203         }
 204
 205         /**
 206          * Check that a set of files are consistent across all internal backends
 207          *
 208          * @param array $paths List of storage paths
 209          * @return Status
 210          */
 211         public function consistencyCheck( array $paths ) {
 212                 $status = Status::newGood();
 213                 if ( $this->syncChecks == 0 || count( $this->backends ) <= 1 ) {
 214                         return $status; // skip checks
 215                 }
 216
 217                 $mBackend = $this->backends[$this->masterIndex];
 218                 foreach ( $paths as $path ) {
 219                         $params = array( 'src' => $path, 'latest' => true );
 220                         $mParams = $this->substOpPaths( $params, $mBackend );
 221                         // Stat the file on the 'master' backend
 222                         $mStat = $mBackend->getFileStat( $mParams );
 223                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 224                                 $mSha1 = $mBackend->getFileSha1Base36( $mParams );
 225                         } else {
 226                                 $mSha1 = false;
 227                         }
 228                         // Check if all clone backends agree with the master...
 229                         foreach ( $this->backends as $index => $cBackend ) {
 230                                 if ( $index === $this->masterIndex ) {
 231                                         continue; // master
 232                                 }
 233                                 $cParams = $this->substOpPaths( $params, $cBackend );
 234                                 $cStat = $cBackend->getFileStat( $cParams );
 235                                 if ( $mStat ) { // file is in master
 236                                         if ( !$cStat ) { // file should exist
 237                                                 $status->fatal( 'backend-fail-synced', $path );
 238                                                 continue;
 239                                         }
 240                                         if ( $this->syncChecks & self::CHECK_SIZE ) {
 241                                                 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
 242                                                         $status->fatal( 'backend-fail-synced', $path );
 243                                                         continue;
 244                                                 }
 245                                         }
 246                                         if ( $this->syncChecks & self::CHECK_TIME ) {
 247                                                 $mTs = wfTimestamp( TS_UNIX, $mStat['mtime'] );
 248                                                 $cTs = wfTimestamp( TS_UNIX, $cStat['mtime'] );
 249                                                 if ( abs( $mTs - $cTs ) > 30 ) { // outdated file somewhere
 250                                                         $status->fatal( 'backend-fail-synced', $path );
 251                                                         continue;
 252                                                 }
 253                                         }
 254                                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 255                                                 if ( $cBackend->getFileSha1Base36( $cParams ) !== $mSha1 ) { // wrong SHA1
 256                                                         $status->fatal( 'backend-fail-synced', $path );
 257                                                         continue;
 258                                                 }
 259                                         }
 260                                 } else { // file is not in master
 261                                         if ( $cStat ) { // file should not exist
 262                                                 $status->fatal( 'backend-fail-synced', $path );
 263                                         }
 264                                 }
 265                         }
 266                 }
 267
 268                 return $status;
 269         }
 270
 271         /**
 272          * Check that a set of file paths are usable across all internal backends
 273          *
 274          * @param array $paths List of storage paths
 275          * @return Status
 276          */
 277         public function accessibilityCheck( array $paths ) {
 278                 $status = Status::newGood();
 279                 if ( count( $this->backends ) <= 1 ) {
 280                         return $status; // skip checks
 281                 }
 282
 283                 foreach ( $paths as $path ) {
 284                         foreach ( $this->backends as $backend ) {
 285                                 $realPath = $this->substPaths( $path, $backend );
 286                                 if ( !$backend->isPathUsableInternal( $realPath ) ) {
 287                                         $status->fatal( 'backend-fail-usable', $path );
 288                                 }
 289                         }
 290                 }
 291
 292                 return $status;
 293         }
 294
 295         /**
 296          * Check that a set of files are consistent across all internal backends
 297          * and re-synchronize those files againt the "multi master" if needed.
 298          *
 299          * @param array $paths List of storage paths
 300          * @return Status
 301          */
 302         public function resyncFiles( array $paths ) {
 303                 $status = Status::newGood();
 304
 305                 $mBackend = $this->backends[$this->masterIndex];
 306                 foreach ( $paths as $path ) {
 307                         $mPath = $this->substPaths( $path, $mBackend );
 308                         $mSha1 = $mBackend->getFileSha1Base36( array( 'src' => $mPath, 'latest' => true ) );
 309                         $mStat = $mBackend->getFileStat( array( 'src' => $mPath, 'latest' => true ) );
 310                         if ( $mStat === null || ( $mSha1 !== false && !$mStat ) ) { // sanity
 311                                 $status->fatal( 'backend-fail-internal', $this->name );
 312                                 continue; // file is not available on the master backend...
 313                         }
 314                         // Check of all clone backends agree with the master...
 315                         foreach ( $this->backends as $index => $cBackend ) {
 316                                 if ( $index === $this->masterIndex ) {
 317                                         continue; // master
 318                                 }
 319                                 $cPath = $this->substPaths( $path, $cBackend );
 320                                 $cSha1 = $cBackend->getFileSha1Base36( array( 'src' => $cPath, 'latest' => true ) );
 321                                 $cStat = $cBackend->getFileStat( array( 'src' => $cPath, 'latest' => true ) );
 322                                 if ( $cStat === null || ( $cSha1 !== false && !$cStat ) ) { // sanity
 323                                         $status->fatal( 'backend-fail-internal', $cBackend->getName() );
 324                                         continue; // file is not available on the clone backend...
 325                                 }
 326                                 if ( $mSha1 === $cSha1 ) {
 327                                         // already synced; nothing to do
 328                                 } elseif ( $mSha1 !== false ) { // file is in master
 329                                         if ( $this->autoResync === 'conservative'
 330                                                 && $cStat && $cStat['mtime'] > $mStat['mtime'] )
 331                                         {
 332                                                 $status->fatal( 'backend-fail-synced', $path );
 333                                                 continue; // don't rollback data
 334                                         }
 335                                         $fsFile = $mBackend->getLocalReference(
 336                                                 array( 'src' => $mPath, 'latest' => true ) );
 337                                         $status->merge( $cBackend->quickStore(
 338                                                 array( 'src' => $fsFile->getPath(), 'dst' => $cPath )
 339                                         ) );
 340                                 } elseif ( $mStat === false ) { // file is not in master
 341                                         if ( $this->autoResync === 'conservative' ) {
 342                                                 $status->fatal( 'backend-fail-synced', $path );
 343                                                 continue; // don't delete data
 344                                         }
 345                                         $status->merge( $cBackend->quickDelete( array( 'src' => $cPath ) ) );
 346                                 }
 347                         }
 348                 }
 349
 350                 return $status;
 351         }
 352
 353         /**
 354          * Get a list of file storage paths to read or write for a list of operations
 355          *
 356          * @param array $ops Same format as doOperations()
 357          * @return Array List of storage paths to files (does not include directories)
 358          */
 359         protected function fileStoragePathsForOps( array $ops ) {
 360                 $paths = array();
 361                 foreach ( $ops as $op ) {
 362                         if ( isset( $op['src'] ) ) {
 363                                 // For things like copy/move/delete with "ignoreMissingSource" and there
 364                                 // is no source file, nothing should happen and there should be no errors.
 365                                 if ( empty( $op['ignoreMissingSource'] )
 366                                         || $this->fileExists( array( 'src' => $op['src'] ) ) )
 367                                 {
 368                                         $paths[] = $op['src'];
 369                                 }
 370                         }
 371                         if ( isset( $op['srcs'] ) ) {
 372                                 $paths = array_merge( $paths, $op['srcs'] );
 373                         }
 374                         if ( isset( $op['dst'] ) ) {
 375                                 $paths[] = $op['dst'];
 376                         }
 377                 }
 378                 return array_values( array_unique( array_filter( $paths, 'FileBackend::isStoragePath' ) ) );
 379         }
 380
 381         /**
 382          * Substitute the backend name in storage path parameters
 383          * for a set of operations with that of a given internal backend.
 384          *
 385          * @param array $ops List of file operation arrays
 386          * @param FileBackendStore $backend
 387          * @return Array
 388          */
 389         protected function substOpBatchPaths( array $ops, FileBackendStore $backend ) {
 390                 $newOps = array(); // operations
 391                 foreach ( $ops as $op ) {
 392                         $newOp = $op; // operation
 393                         foreach ( array( 'src', 'srcs', 'dst', 'dir' ) as $par ) {
 394                                 if ( isset( $newOp[$par] ) ) { // string or array
 395                                         $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
 396                                 }
 397                         }
 398                         $newOps[] = $newOp;
 399                 }
 400                 return $newOps;
 401         }
 402
 403         /**
 404          * Same as substOpBatchPaths() but for a single operation
 405          *
 406          * @param array $ops File operation array
 407          * @param FileBackendStore $backend
 408          * @return Array
 409          */
 410         protected function substOpPaths( array $ops, FileBackendStore $backend ) {
 411                 $newOps = $this->substOpBatchPaths( array( $ops ), $backend );
 412                 return $newOps[0];
 413         }
 414
 415         /**
 416          * Substitute the backend of storage paths with an internal backend's name
 417          *
 418          * @param array|string $paths List of paths or single string path
 419          * @param FileBackendStore $backend
 420          * @return Array|string
 421          */
 422         protected function substPaths( $paths, FileBackendStore $backend ) {
 423                 return preg_replace(
 424                         '!^mwstore://' . preg_quote( $this->name ) . '/!',
 425                         StringUtils::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
 426                         $paths // string or array
 427                 );
 428         }
 429
 430         /**
 431          * Substitute the backend of internal storage paths with the proxy backend's name
 432          *
 433          * @param array|string $paths List of paths or single string path
 434          * @return Array|string
 435          */
 436         protected function unsubstPaths( $paths ) {
 437                 return preg_replace(
 438                         '!^mwstore://([^/]+)!',
 439                         StringUtils::escapeRegexReplacement( "mwstore://{$this->name}" ),
 440                         $paths // string or array
 441                 );
 442         }
 443
 444         protected function doQuickOperationsInternal( array $ops ) {
 445                 $status = Status::newGood();
 446                 // Do the operations on the master backend; setting Status fields...
 447                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 448                 $masterStatus = $this->backends[$this->masterIndex]->doQuickOperations( $realOps );
 449                 $status->merge( $masterStatus );
 450                 // Propagate the operations to the clone backends...
 451                 if ( !$this->noPushQuickOps ) {
 452                         foreach ( $this->backends as $index => $backend ) {
 453                                 if ( $index !== $this->masterIndex ) { // not done already
 454                                         $realOps = $this->substOpBatchPaths( $ops, $backend );
 455                                         $status->merge( $backend->doQuickOperations( $realOps ) );
 456                                 }
 457                         }
 458                 }
 459                 // Make 'success', 'successCount', and 'failCount' fields reflect
 460                 // the overall operation, rather than all the batches for each backend.
 461                 // Do this by only using success values from the master backend's batch.
 462                 $status->success = $masterStatus->success;
 463                 $status->successCount = $masterStatus->successCount;
 464                 $status->failCount = $masterStatus->failCount;
 465                 return $status;
 466         }
 467
 468         /**
 469          * @param string $path Storage path
 470          * @return bool Path container should have dir changes pushed to all backends
 471          */
 472         protected function replicateContainerDirChanges( $path ) {
 473                 list( , $shortCont, ) = self::splitStoragePath( $path );
 474                 return !in_array( $shortCont, $this->noPushDirConts );
 475         }
 476
 477         protected function doPrepare( array $params ) {
 478                 $status = Status::newGood();
 479                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 480                 foreach ( $this->backends as $index => $backend ) {
 481                         if ( $replicate || $index == $this->masterIndex ) {
 482                                 $realParams = $this->substOpPaths( $params, $backend );
 483                                 $status->merge( $backend->doPrepare( $realParams ) );
 484                         }
 485                 }
 486                 return $status;
 487         }
 488
 489         protected function doSecure( array $params ) {
 490                 $status = Status::newGood();
 491                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 492                 foreach ( $this->backends as $index => $backend ) {
 493                         if ( $replicate || $index == $this->masterIndex ) {
 494                                 $realParams = $this->substOpPaths( $params, $backend );
 495                                 $status->merge( $backend->doSecure( $realParams ) );
 496                         }
 497                 }
 498                 return $status;
 499         }
 500
 501         protected function doPublish( array $params ) {
 502                 $status = Status::newGood();
 503                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 504                 foreach ( $this->backends as $index => $backend ) {
 505                         if ( $replicate || $index == $this->masterIndex ) {
 506                                 $realParams = $this->substOpPaths( $params, $backend );
 507                                 $status->merge( $backend->doPublish( $realParams ) );
 508                         }
 509                 }
 510                 return $status;
 511         }
 512
 513         protected function doClean( array $params ) {
 514                 $status = Status::newGood();
 515                 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
 516                 foreach ( $this->backends as $index => $backend ) {
 517                         if ( $replicate || $index == $this->masterIndex ) {
 518                                 $realParams = $this->substOpPaths( $params, $backend );
 519                                 $status->merge( $backend->doClean( $realParams ) );
 520                         }
 521                 }
 522                 return $status;
 523         }
 524
 525         public function concatenate( array $params ) {
 526                 // We are writing to an FS file, so we don't need to do this per-backend
 527                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 528                 return $this->backends[$this->masterIndex]->concatenate( $realParams );
 529         }
 530
 531         public function fileExists( array $params ) {
 532                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 533                 return $this->backends[$this->masterIndex]->fileExists( $realParams );
 534         }
 535
 536         public function getFileTimestamp( array $params ) {
 537                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 538                 return $this->backends[$this->masterIndex]->getFileTimestamp( $realParams );
 539         }
 540
 541         public function getFileSize( array $params ) {
 542                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 543                 return $this->backends[$this->masterIndex]->getFileSize( $realParams );
 544         }
 545
 546         public function getFileStat( array $params ) {
 547                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 548                 return $this->backends[$this->masterIndex]->getFileStat( $realParams );
 549         }
 550
 551         public function getFileContentsMulti( array $params ) {
 552                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 553                 $contentsM = $this->backends[$this->masterIndex]->getFileContentsMulti( $realParams );
 554
 555                 $contents = array(); // (path => FSFile) mapping using the proxy backend's name
 556                 foreach ( $contentsM as $path => $data ) {
 557                         $contents[$this->unsubstPaths( $path )] = $data;
 558                 }
 559                 return $contents;
 560         }
 561
 562         public function getFileSha1Base36( array $params ) {
 563                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 564                 return $this->backends[$this->masterIndex]->getFileSha1Base36( $realParams );
 565         }
 566
 567         public function getFileProps( array $params ) {
 568                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 569                 return $this->backends[$this->masterIndex]->getFileProps( $realParams );
 570         }
 571
 572         public function streamFile( array $params ) {
 573                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 574                 return $this->backends[$this->masterIndex]->streamFile( $realParams );
 575         }
 576
 577         public function getLocalReferenceMulti( array $params ) {
 578                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 579                 $fsFilesM = $this->backends[$this->masterIndex]->getLocalReferenceMulti( $realParams );
 580
 581                 $fsFiles = array(); // (path => FSFile) mapping using the proxy backend's name
 582                 foreach ( $fsFilesM as $path => $fsFile ) {
 583                         $fsFiles[$this->unsubstPaths( $path )] = $fsFile;
 584                 }
 585                 return $fsFiles;
 586         }
 587
 588         public function getLocalCopyMulti( array $params ) {
 589                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 590                 $tempFilesM = $this->backends[$this->masterIndex]->getLocalCopyMulti( $realParams );
 591
 592                 $tempFiles = array(); // (path => TempFSFile) mapping using the proxy backend's name
 593                 foreach ( $tempFilesM as $path => $tempFile ) {
 594                         $tempFiles[$this->unsubstPaths( $path )] = $tempFile;
 595                 }
 596                 return $tempFiles;
 597         }
 598
 599         public function getFileHttpUrl( array $params ) {
 600                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 601                 return $this->backends[$this->masterIndex]->getFileHttpUrl( $realParams );
 602         }
 603
 604         public function directoryExists( array $params ) {
 605                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 606                 return $this->backends[$this->masterIndex]->directoryExists( $realParams );
 607         }
 608
 609         public function getDirectoryList( array $params ) {
 610                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 611                 return $this->backends[$this->masterIndex]->getDirectoryList( $realParams );
 612         }
 613
 614         public function getFileList( array $params ) {
 615                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 616                 return $this->backends[$this->masterIndex]->getFileList( $realParams );
 617         }
 618
 619         public function clearCache( array $paths = null ) {
 620                 foreach ( $this->backends as $backend ) {
 621                         $realPaths = is_array( $paths ) ? $this->substPaths( $paths, $backend ) : null;
 622                         $backend->clearCache( $realPaths );
 623                 }
 624         }
 625
 626         public function getScopedLocksForOps( array $ops, Status $status ) {
 627                 $fileOps = $this->backends[$this->masterIndex]->getOperationsInternal( $ops );
 628                 // Get the paths to lock from the master backend
 629                 $paths = $this->backends[$this->masterIndex]->getPathsToLockForOpsInternal( $fileOps );
 630                 // Get the paths under the proxy backend's name
 631                 $paths['sh'] = $this->unsubstPaths( $paths['sh'] );
 632                 $paths['ex'] = $this->unsubstPaths( $paths['ex'] );
 633                 return array(
 634                         $this->getScopedFileLocks( $paths['sh'], LockManager::LOCK_UW, $status ),
 635                         $this->getScopedFileLocks( $paths['ex'], LockManager::LOCK_EX, $status )
 636                 );
 637         }
 638 }