src/store_dir.cc

   1
   2 /*
   3  * $Id$
   4  *
   5  * DEBUG: section 47    Store Directory Routines
   6  * AUTHOR: Duane Wessels
   7  *
   8  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   9  * ----------------------------------------------------------
  10  *
  11  *  Squid is the result of efforts by numerous individuals from
  12  *  the Internet community; see the CONTRIBUTORS file for full
  13  *  details.   Many organizations have provided support for Squid's
  14  *  development; see the SPONSORS file for full details.  Squid is
  15  *  Copyrighted (C) 2001 by the Regents of the University of
  16  *  California; see the COPYRIGHT file for full details.  Squid
  17  *  incorporates software developed and/or copyrighted by other
  18  *  sources; see the CREDITS file for full details.
  19  *
  20  *  This program is free software; you can redistribute it and/or modify
  21  *  it under the terms of the GNU General Public License as published by
  22  *  the Free Software Foundation; either version 2 of the License, or
  23  *  (at your option) any later version.
  24  *
  25  *  This program is distributed in the hope that it will be useful,
  26  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *  GNU General Public License for more details.
  29  *
  30  *  You should have received a copy of the GNU General Public License
  31  *  along with this program; if not, write to the Free Software
  32  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  33  *
  34  */
  35
  36 #include "squid.h"
  37 #include "Store.h"
  38 #include "MemObject.h"
  39 #include "MemStore.h"
  40 #include "mem_node.h"
  41 #include "SquidMath.h"
  42 #include "SquidTime.h"
  43 #include "SwapDir.h"
  44 #include "swap_log_op.h"
  45
  46 #if HAVE_STATVFS
  47 #if HAVE_SYS_STATVFS_H
  48 #include <sys/statvfs.h>
  49 #endif
  50 #endif /* HAVE_STATVFS */
  51 /* statfs() needs <sys/param.h> and <sys/mount.h> on BSD systems */
  52 #if HAVE_SYS_PARAM_H
  53 #include <sys/param.h>
  54 #endif
  55 #if HAVE_SYS_MOUNT_H
  56 #include <sys/mount.h>
  57 #endif
  58 /* Windows and Linux use sys/vfs.h */
  59 #if HAVE_SYS_VFS_H
  60 #include <sys/vfs.h>
  61 #endif
  62
  63 #include "StoreHashIndex.h"
  64
  65 static STDIRSELECT storeDirSelectSwapDirRoundRobin;
  66 static STDIRSELECT storeDirSelectSwapDirLeastLoad;
  67
  68 /*
  69  * store_dirs_rebuilding is initialized to _1_ as a hack so that
  70  * storeDirWriteCleanLogs() doesn't try to do anything unless _all_
  71  * cache_dirs have been read.  For example, without this hack, Squid
  72  * will try to write clean log files if -kparse fails (becasue it
  73  * calls fatal()).
  74  */
  75 int StoreController::store_dirs_rebuilding = 1;
  76
  77 StoreController::StoreController() : swapDir (new StoreHashIndex())
  78         , memStore(NULL)
  79 {}
  80
  81 StoreController::~StoreController()
  82 {
  83     delete memStore;
  84 }
  85
  86 /*
  87  * This function pointer is set according to 'store_dir_select_algorithm'
  88  * in squid.conf.
  89  */
  90 STDIRSELECT *storeDirSelectSwapDir = storeDirSelectSwapDirLeastLoad;
  91
  92 void
  93 StoreController::init()
  94 {
  95     if (Config.memShared && IamWorkerProcess()) {
  96         memStore = new MemStore;
  97         memStore->init();
  98     }
  99
 100     swapDir->init();
 101
 102     if (0 == strcasecmp(Config.store_dir_select_algorithm, "round-robin")) {
 103         storeDirSelectSwapDir = storeDirSelectSwapDirRoundRobin;
 104         debugs(47, 1, "Using Round Robin store dir selection");
 105     } else {
 106         storeDirSelectSwapDir = storeDirSelectSwapDirLeastLoad;
 107         debugs(47, 1, "Using Least Load store dir selection");
 108     }
 109 }
 110
 111 void
 112 StoreController::createOneStore(Store &aStore)
 113 {
 114     /*
 115      * On Windows, fork() is not available.
 116      * The following is a workaround for create store directories sequentially
 117      * when running on native Windows port.
 118      */
 119 #if !_SQUID_MSWIN_
 120
 121     if (fork())
 122         return;
 123
 124 #endif
 125
 126     aStore.create();
 127
 128 #if !_SQUID_MSWIN_
 129
 130     exit(0);
 131
 132 #endif
 133 }
 134
 135 void
 136 StoreController::create()
 137 {
 138     swapDir->create();
 139
 140 #if !_SQUID_MSWIN_
 141
 142     pid_t pid;
 143
 144     do {
 145         int status;
 146 #if _SQUID_NEXT_
 147
 148         pid = wait3(&status, WNOHANG, NULL);
 149 #else
 150
 151         pid = waitpid(-1, &status, 0);
 152 #endif
 153
 154     } while (pid > 0 || (pid < 0 && errno == EINTR));
 155
 156 #endif
 157 }
 158
 159 /**
 160  * Determine whether the given directory can handle this object
 161  * size
 162  *
 163  * Note: if the object size is -1, then the only swapdirs that
 164  * will return true here are ones that have min and max unset,
 165  * ie any-sized-object swapdirs. This is a good thing.
 166  */
 167 bool
 168 SwapDir::objectSizeIsAcceptable(int64_t objsize) const
 169 {
 170     // If the swapdir has no range limits, then it definitely can
 171     if (min_objsize <= 0 && max_objsize == -1)
 172         return true;
 173
 174     /*
 175      * If the object size is -1 and the storedir has limits we
 176      * can't store it there.
 177      */
 178     if (objsize == -1)
 179         return false;
 180
 181     // Else, make sure that the object size will fit.
 182     if (max_objsize == -1 && min_objsize <= objsize)
 183         return true;
 184     else
 185         return min_objsize <= objsize && max_objsize > objsize;
 186 }
 187
 188
 189 /*
 190  * This new selection scheme simply does round-robin on all SwapDirs.
 191  * A SwapDir is skipped if it is over the max_size (100%) limit, or
 192  * overloaded.
 193  */
 194 static int
 195 storeDirSelectSwapDirRoundRobin(const StoreEntry * e)
 196 {
 197     static int dirn = 0;
 198     int i;
 199     int load;
 200     RefCount<SwapDir> sd;
 201
 202     // e->objectLen() is negative at this point when we are still STORE_PENDING
 203     ssize_t objsize = e->mem_obj->expectedReplySize();
 204     if (objsize != -1)
 205         objsize += e->mem_obj->swap_hdr_sz;
 206
 207     for (i = 0; i < Config.cacheSwap.n_configured; i++) {
 208         if (++dirn >= Config.cacheSwap.n_configured)
 209             dirn = 0;
 210
 211         sd = dynamic_cast<SwapDir *>(INDEXSD(dirn));
 212
 213         if (!sd->canStore(*e, objsize, load))
 214             continue;
 215
 216         if (load < 0 || load > 1000) {
 217             continue;
 218         }
 219
 220         return dirn;
 221     }
 222
 223     return -1;
 224 }
 225
 226 /*
 227  * Spread load across all of the store directories
 228  *
 229  * Note: We should modify this later on to prefer sticking objects
 230  * in the *tightest fit* swapdir to conserve space, along with the
 231  * actual swapdir usage. But for now, this hack will do while
 232  * testing, so you should order your swapdirs in the config file
 233  * from smallest maxobjsize to unlimited (-1) maxobjsize.
 234  *
 235  * We also have to choose nleast == nconf since we need to consider
 236  * ALL swapdirs, regardless of state. Again, this is a hack while
 237  * we sort out the real usefulness of this algorithm.
 238  */
 239 static int
 240 storeDirSelectSwapDirLeastLoad(const StoreEntry * e)
 241 {
 242     int64_t most_free = 0;
 243     ssize_t least_objsize = -1;
 244     int least_load = INT_MAX;
 245     int load;
 246     int dirn = -1;
 247     int i;
 248     RefCount<SwapDir> SD;
 249
 250     // e->objectLen() is negative at this point when we are still STORE_PENDING
 251     ssize_t objsize = e->mem_obj->expectedReplySize();
 252
 253     if (objsize != -1)
 254         objsize += e->mem_obj->swap_hdr_sz;
 255
 256     for (i = 0; i < Config.cacheSwap.n_configured; i++) {
 257         SD = dynamic_cast<SwapDir *>(INDEXSD(i));
 258         SD->flags.selected = 0;
 259
 260         if (!SD->canStore(*e, objsize, load))
 261             continue;
 262
 263         if (load < 0 || load > 1000)
 264             continue;
 265
 266         if (load > least_load)
 267             continue;
 268
 269         const int64_t cur_free = SD->maxSize() - SD->currentSize();
 270
 271         /* If the load is equal, then look in more details */
 272         if (load == least_load) {
 273             /* closest max_objsize fit */
 274
 275             if (least_objsize != -1)
 276                 if (SD->max_objsize > least_objsize || SD->max_objsize == -1)
 277                     continue;
 278
 279             /* most free */
 280             if (cur_free < most_free)
 281                 continue;
 282         }
 283
 284         least_load = load;
 285         least_objsize = SD->max_objsize;
 286         most_free = cur_free;
 287         dirn = i;
 288     }
 289
 290     if (dirn >= 0)
 291         dynamic_cast<SwapDir *>(INDEXSD(dirn))->flags.selected = 1;
 292
 293     return dirn;
 294 }
 295
 296 /*
 297  * An entry written to the swap log MUST have the following
 298  * properties.
 299  *   1.  It MUST be a public key.  It does no good to log
 300  *       a public ADD, change the key, then log a private
 301  *       DEL.  So we need to log a DEL before we change a
 302  *       key from public to private.
 303  *   2.  It MUST have a valid (> -1) swap_filen.
 304  */
 305 void
 306 storeDirSwapLog(const StoreEntry * e, int op)
 307 {
 308     assert (e);
 309     assert(!EBIT_TEST(e->flags, KEY_PRIVATE));
 310     assert(e->swap_filen >= 0);
 311     /*
 312      * icons and such; don't write them to the swap log
 313      */
 314
 315     if (EBIT_TEST(e->flags, ENTRY_SPECIAL))
 316         return;
 317
 318     assert(op > SWAP_LOG_NOP && op < SWAP_LOG_MAX);
 319
 320     debugs(20, 3, "storeDirSwapLog: " <<
 321            swap_log_op_str[op] << " " <<
 322            e->getMD5Text() << " " <<
 323            e->swap_dirn << " " <<
 324            std::hex << std::uppercase << std::setfill('0') << std::setw(8) << e->swap_filen);
 325
 326     dynamic_cast<SwapDir *>(INDEXSD(e->swap_dirn))->logEntry(*e, op);
 327 }
 328
 329 void
 330 StoreController::stat(StoreEntry &output) const
 331 {
 332     storeAppendPrintf(&output, "Store Directory Statistics:\n");
 333     storeAppendPrintf(&output, "Store Entries          : %lu\n",
 334                       (unsigned long int)StoreEntry::inUseCount());
 335     storeAppendPrintf(&output, "Maximum Swap Size      : %"PRIu64" KB\n",
 336                       maxSize() >> 10);
 337     storeAppendPrintf(&output, "Current Store Swap Size: %.2f KB\n",
 338                       currentSize() / 1024.0);
 339     storeAppendPrintf(&output, "Current Capacity       : %.2f%% used, %.2f%% free\n",
 340                       Math::doublePercent(currentSize(), maxSize()),
 341                       Math::doublePercent((maxSize() - currentSize()), maxSize()));
 342
 343     if (memStore)
 344         memStore->stat(output);
 345
 346     /* now the swapDir */
 347     swapDir->stat(output);
 348 }
 349
 350 /* if needed, this could be taught to cache the result */
 351 uint64_t
 352 StoreController::maxSize() const
 353 {
 354     /* TODO: include memory cache ? */
 355     return swapDir->maxSize();
 356 }
 357
 358 uint64_t
 359 StoreController::minSize() const
 360 {
 361     /* TODO: include memory cache ? */
 362     return swapDir->minSize();
 363 }
 364
 365 uint64_t
 366 StoreController::currentSize() const
 367 {
 368     return swapDir->currentSize();
 369 }
 370
 371 uint64_t
 372 StoreController::currentCount() const
 373 {
 374     return swapDir->currentCount();
 375 }
 376
 377 int64_t
 378 StoreController::maxObjectSize() const
 379 {
 380     return swapDir->maxObjectSize();
 381 }
 382
 383 void
 384 SwapDir::diskFull()
 385 {
 386     if (currentSize() >= maxSize())
 387         return;
 388
 389     max_size = currentSize();
 390
 391     debugs(20, 1, "WARNING: Shrinking cache_dir #" << index << " to " << currentSize() / 1024.0 << " KB");
 392 }
 393
 394 void
 395 storeDirOpenSwapLogs(void)
 396 {
 397     for (int dirn = 0; dirn < Config.cacheSwap.n_configured; ++dirn)
 398         dynamic_cast<SwapDir *>(INDEXSD(dirn))->openLog();
 399 }
 400
 401 void
 402 storeDirCloseSwapLogs(void)
 403 {
 404     for (int dirn = 0; dirn < Config.cacheSwap.n_configured; ++dirn)
 405         dynamic_cast<SwapDir *>(INDEXSD(dirn))->closeLog();
 406 }
 407
 408 /*
 409  *  storeDirWriteCleanLogs
 410  *
 411  *  Writes a "clean" swap log file from in-memory metadata.
 412  *  This is a rewrite of the original function to troll each
 413  *  StoreDir and write the logs, and flush at the end of
 414  *  the run. Thanks goes to Eric Stern, since this solution
 415  *  came out of his COSS code.
 416  */
 417 int
 418 storeDirWriteCleanLogs(int reopen)
 419 {
 420     const StoreEntry *e = NULL;
 421     int n = 0;
 422
 423     struct timeval start;
 424     double dt;
 425     RefCount<SwapDir> sd;
 426     int dirn;
 427     int notdone = 1;
 428
 429     if (StoreController::store_dirs_rebuilding) {
 430         debugs(20, 1, "Not currently OK to rewrite swap log.");
 431         debugs(20, 1, "storeDirWriteCleanLogs: Operation aborted.");
 432         return 0;
 433     }
 434
 435     debugs(20, 1, "storeDirWriteCleanLogs: Starting...");
 436     getCurrentTime();
 437     start = current_time;
 438
 439     for (dirn = 0; dirn < Config.cacheSwap.n_configured; dirn++) {
 440         sd = dynamic_cast<SwapDir *>(INDEXSD(dirn));
 441
 442         if (sd->writeCleanStart() < 0) {
 443             debugs(20, 1, "log.clean.start() failed for dir #" << sd->index);
 444             continue;
 445         }
 446     }
 447
 448     /*
 449      * This may look inefficient as CPU wise it is more efficient to do this
 450      * sequentially, but I/O wise the parallellism helps as it allows more
 451      * hdd spindles to be active.
 452      */
 453     while (notdone) {
 454         notdone = 0;
 455
 456         for (dirn = 0; dirn < Config.cacheSwap.n_configured; dirn++) {
 457             sd = dynamic_cast<SwapDir *>(INDEXSD(dirn));
 458
 459             if (NULL == sd->cleanLog)
 460                 continue;
 461
 462             e = sd->cleanLog->nextEntry();
 463
 464             if (!e)
 465                 continue;
 466
 467             notdone = 1;
 468
 469             if (!sd->canLog(*e))
 470                 continue;
 471
 472             sd->cleanLog->write(*e);
 473
 474             if ((++n & 0xFFFF) == 0) {
 475                 getCurrentTime();
 476                 debugs(20, 1, "  " << std::setw(7) << n  <<
 477                        " entries written so far.");
 478             }
 479         }
 480     }
 481
 482     /* Flush */
 483     for (dirn = 0; dirn < Config.cacheSwap.n_configured; dirn++)
 484         dynamic_cast<SwapDir *>(INDEXSD(dirn))->writeCleanDone();
 485
 486     if (reopen)
 487         storeDirOpenSwapLogs();
 488
 489     getCurrentTime();
 490
 491     dt = tvSubDsec(start, current_time);
 492
 493     debugs(20, 1, "  Finished.  Wrote " << n << " entries.");
 494     debugs(20, 1, "  Took "<< std::setw(3)<< std::setprecision(2) << dt <<
 495            " seconds ("<< std::setw(6) << ((double) n / (dt > 0.0 ? dt : 1.0)) << " entries/sec).");
 496
 497
 498     return n;
 499 }
 500
 501 StoreSearch *
 502 StoreController::search(String const url, HttpRequest *request)
 503 {
 504     /* cheat, for now you can't search the memory hot cache */
 505     return swapDir->search(url, request);
 506 }
 507
 508 StorePointer
 509 StoreHashIndex::store(int const x) const
 510 {
 511     return INDEXSD(x);
 512 }
 513
 514 SwapDir &
 515 StoreHashIndex::dir(const int i) const
 516 {
 517     SwapDir *sd = dynamic_cast<SwapDir*>(INDEXSD(i));
 518     assert(sd);
 519     return *sd;
 520 }
 521
 522 void
 523 StoreController::sync(void)
 524 {
 525     if (memStore)
 526         memStore->sync();
 527     swapDir->sync();
 528 }
 529
 530 /*
 531  * handle callbacks all avaliable fs'es
 532  */
 533 int
 534 StoreController::callback()
 535 {
 536     /* This will likely double count. Thats ok. */
 537     PROF_start(storeDirCallback);
 538
 539     /* mem cache callbacks ? */
 540     int result = swapDir->callback();
 541
 542     PROF_stop(storeDirCallback);
 543
 544     return result;
 545 }
 546
 547 int
 548 storeDirGetBlkSize(const char *path, int *blksize)
 549 {
 550 #if HAVE_STATVFS
 551
 552     struct statvfs sfs;
 553
 554     if (statvfs(path, &sfs)) {
 555         debugs(50, 1, "" << path << ": " << xstrerror());
 556         *blksize = 2048;
 557         return 1;
 558     }
 559
 560     *blksize = (int) sfs.f_frsize;
 561 #else
 562
 563     struct statfs sfs;
 564
 565     if (statfs(path, &sfs)) {
 566         debugs(50, 1, "" << path << ": " << xstrerror());
 567         *blksize = 2048;
 568         return 1;
 569     }
 570
 571     *blksize = (int) sfs.f_bsize;
 572 #endif
 573     /*
 574      * Sanity check; make sure we have a meaningful value.
 575      */
 576
 577     if (*blksize < 512)
 578         *blksize = 2048;
 579
 580     return 0;
 581 }
 582
 583 #define fsbtoblk(num, fsbs, bs) \
 584     (((fsbs) != 0 && (fsbs) < (bs)) ? \
 585             (num) / ((bs) / (fsbs)) : (num) * ((fsbs) / (bs)))
 586 int
 587 storeDirGetUFSStats(const char *path, int *totl_kb, int *free_kb, int *totl_in, int *free_in)
 588 {
 589 #if HAVE_STATVFS
 590
 591     struct statvfs sfs;
 592
 593     if (statvfs(path, &sfs)) {
 594         debugs(50, 1, "" << path << ": " << xstrerror());
 595         return 1;
 596     }
 597
 598     *totl_kb = (int) fsbtoblk(sfs.f_blocks, sfs.f_frsize, 1024);
 599     *free_kb = (int) fsbtoblk(sfs.f_bfree, sfs.f_frsize, 1024);
 600     *totl_in = (int) sfs.f_files;
 601     *free_in = (int) sfs.f_ffree;
 602 #else
 603
 604     struct statfs sfs;
 605
 606     if (statfs(path, &sfs)) {
 607         debugs(50, 1, "" << path << ": " << xstrerror());
 608         return 1;
 609     }
 610
 611     *totl_kb = (int) fsbtoblk(sfs.f_blocks, sfs.f_bsize, 1024);
 612     *free_kb = (int) fsbtoblk(sfs.f_bfree, sfs.f_bsize, 1024);
 613     *totl_in = (int) sfs.f_files;
 614     *free_in = (int) sfs.f_ffree;
 615 #endif
 616
 617     return 0;
 618 }
 619
 620 void
 621 allocate_new_swapdir(SquidConfig::_cacheSwap * swap)
 622 {
 623     if (swap->swapDirs == NULL) {
 624         swap->n_allocated = 4;
 625         swap->swapDirs = static_cast<SwapDir::Pointer *>(xcalloc(swap->n_allocated, sizeof(SwapDir::Pointer)));
 626     }
 627
 628     if (swap->n_allocated == swap->n_configured) {
 629         swap->n_allocated <<= 1;
 630         SwapDir::Pointer *const tmp = static_cast<SwapDir::Pointer *>(xcalloc(swap->n_allocated, sizeof(SwapDir::Pointer)));
 631         memcpy(tmp, swap->swapDirs, swap->n_configured * sizeof(SwapDir *));
 632         xfree(swap->swapDirs);
 633         swap->swapDirs = tmp;
 634     }
 635 }
 636
 637 void
 638 free_cachedir(SquidConfig::_cacheSwap * swap)
 639 {
 640     int i;
 641     /* DON'T FREE THESE FOR RECONFIGURE */
 642
 643     if (reconfiguring)
 644         return;
 645
 646     for (i = 0; i < swap->n_configured; i++) {
 647         /* TODO XXX this lets the swapdir free resources asynchronously
 648         * swap->swapDirs[i]->deactivate();
 649         * but there may be such a means already.
 650         * RBC 20041225
 651         */
 652         swap->swapDirs[i] = NULL;
 653     }
 654
 655     safe_free(swap->swapDirs);
 656     swap->swapDirs = NULL;
 657     swap->n_allocated = 0;
 658     swap->n_configured = 0;
 659 }
 660
 661 /* this should be a virtual method on StoreEntry,
 662  * i.e. e->referenced()
 663  * so that the entry can notify the creating Store
 664  */
 665 void
 666 StoreController::reference(StoreEntry &e)
 667 {
 668     /* Notify the fs that we're referencing this object again */
 669
 670     if (e.swap_dirn > -1)
 671         swapDir->reference(e);
 672
 673     // Notify the memory cache that we're referencing this object again
 674     if (memStore && e.mem_status == IN_MEMORY)
 675         memStore->reference(e);
 676
 677     // TODO: move this code to a non-shared memory cache class when we have it
 678     if (e.mem_obj) {
 679         if (mem_policy->Referenced)
 680             mem_policy->Referenced(mem_policy, &e, &e.mem_obj->repl);
 681     }
 682 }
 683
 684 bool
 685 StoreController::dereference(StoreEntry & e)
 686 {
 687     bool keepInStoreTable = false;
 688
 689     /* Notify the fs that we're not referencing this object any more */
 690
 691     if (e.swap_filen > -1)
 692         keepInStoreTable = swapDir->dereference(e) || keepInStoreTable;
 693
 694     // Notify the memory cache that we're not referencing this object any more
 695     if (memStore && e.mem_status == IN_MEMORY)
 696         keepInStoreTable = memStore->dereference(e) || keepInStoreTable;
 697
 698     // TODO: move this code to a non-shared memory cache class when we have it
 699     if (e.mem_obj) {
 700         if (mem_policy->Dereferenced)
 701             mem_policy->Dereferenced(mem_policy, &e, &e.mem_obj->repl);
 702     }
 703
 704     return keepInStoreTable;
 705 }
 706
 707 StoreEntry *
 708 StoreController::get(const cache_key *key)
 709 {
 710     if (StoreEntry *e = swapDir->get(key)) {
 711         // TODO: ignore and maybe handleIdleEntry() unlocked intransit entries
 712         // because their backing store slot may be gone already.
 713         debugs(20, 3, HERE << "got in-transit entry: " << *e);
 714         return e;
 715     }
 716
 717     if (memStore) {
 718         if (StoreEntry *e = memStore->get(key)) {
 719             debugs(20, 3, HERE << "got mem-cached entry: " << *e);
 720             return e;
 721         }
 722     }
 723
 724     // TODO: this disk iteration is misplaced; move to StoreHashIndex when
 725     // the global store_table is no longer used for in-transit objects.
 726     if (const int cacheDirs = Config.cacheSwap.n_configured) {
 727         // ask each cache_dir until the entry is found; use static starting
 728         // point to avoid asking the same subset of disks more often
 729         // TODO: coordinate with put() to be able to guess the right disk often
 730         static int idx = 0;
 731         for (int n = 0; n < cacheDirs; ++n) {
 732             idx = (idx + 1) % cacheDirs;
 733             SwapDir *sd = dynamic_cast<SwapDir*>(INDEXSD(idx));
 734             if (!sd->active())
 735                 continue;
 736
 737             if (StoreEntry *e = sd->get(key)) {
 738                 debugs(20, 3, HERE << "cache_dir " << idx <<
 739                        " got cached entry: " << *e);
 740                 return e;
 741             }
 742         }
 743     }
 744
 745     debugs(20, 4, HERE << "none of " << Config.cacheSwap.n_configured <<
 746            " cache_dirs have " << storeKeyText(key));
 747     return NULL;
 748 }
 749
 750 void
 751 StoreController::get(String const key, STOREGETCLIENT aCallback, void *aCallbackData)
 752 {
 753     fatal("not implemented");
 754 }
 755
 756 void
 757 StoreController::handleIdleEntry(StoreEntry &e)
 758 {
 759     bool keepInLocalMemory = false;
 760     if (memStore) {
 761         memStore->considerKeeping(e);
 762         // leave keepInLocalMemory false; memStore maintains its own cache
 763     } else {
 764         keepInLocalMemory = e.memoryCachable() && // entry is in good shape and
 765                             // the local memory cache is not overflowing
 766                             (mem_node::InUseCount() <= store_pages_max);
 767     }
 768
 769     // An idle, unlocked entry that belongs to a SwapDir which controls
 770     // its own index, should not stay in the global store_table.
 771     if (!dereference(e)) {
 772         debugs(20, 5, HERE << "destroying unlocked entry: " << &e << ' ' << e);
 773         destroyStoreEntry(static_cast<hash_link*>(&e));
 774         return;
 775     }
 776
 777     // TODO: move this into [non-shared] memory cache class when we have one
 778     if (keepInLocalMemory) {
 779         e.setMemStatus(IN_MEMORY);
 780         e.mem_obj->unlinkRequest();
 781     } else {
 782         e.purgeMem(); // may free e
 783     }
 784 }
 785
 786 StoreHashIndex::StoreHashIndex()
 787 {
 788     if (store_table)
 789         abort();
 790     assert (store_table == NULL);
 791 }
 792
 793 StoreHashIndex::~StoreHashIndex()
 794 {
 795     if (store_table) {
 796         hashFreeItems(store_table, destroyStoreEntry);
 797         hashFreeMemory(store_table);
 798         store_table = NULL;
 799     }
 800 }
 801
 802 int
 803 StoreHashIndex::callback()
 804 {
 805     int result = 0;
 806     int j;
 807     static int ndir = 0;
 808
 809     do {
 810         j = 0;
 811
 812         for (int i = 0; i < Config.cacheSwap.n_configured; i++) {
 813             if (ndir >= Config.cacheSwap.n_configured)
 814                 ndir = ndir % Config.cacheSwap.n_configured;
 815
 816             int temp_result = store(ndir)->callback();
 817
 818             ++ndir;
 819
 820             j += temp_result;
 821
 822             result += temp_result;
 823
 824             if (j > 100)
 825                 fatal ("too much io\n");
 826         }
 827     } while (j > 0);
 828
 829     ndir++;
 830
 831     return result;
 832 }
 833
 834 void
 835 StoreHashIndex::create()
 836 {
 837     for (int i = 0; i < Config.cacheSwap.n_configured; i++) {
 838         if (dir(i).active())
 839             store(i)->create();
 840     }
 841 }
 842
 843 /* Lookup an object in the cache.
 844  * return just a reference to object, don't start swapping in yet. */
 845 StoreEntry *
 846 StoreHashIndex::get(const cache_key *key)
 847 {
 848     PROF_start(storeGet);
 849     debugs(20, 3, "storeGet: looking up " << storeKeyText(key));
 850     StoreEntry *p = static_cast<StoreEntry *>(hash_lookup(store_table, key));
 851     PROF_stop(storeGet);
 852     return p;
 853 }
 854
 855 void
 856 StoreHashIndex::get(String const key, STOREGETCLIENT aCallback, void *aCallbackData)
 857 {
 858     fatal("not implemented");
 859 }
 860
 861 void
 862 StoreHashIndex::init()
 863 {
 864     /* Calculate size of hash table (maximum currently 64k buckets).  */
 865     /* this is very bogus, its specific to the any Store maintaining an
 866      * in-core index, not global */
 867     size_t buckets = (Store::Root().maxSize() + Config.memMaxSize) / Config.Store.avgObjectSize;
 868     debugs(20, 1, "Swap maxSize " << (Store::Root().maxSize() >> 10) <<
 869            " + " << ( Config.memMaxSize >> 10) << " KB, estimated " << buckets << " objects");
 870     buckets /= Config.Store.objectsPerBucket;
 871     debugs(20, 1, "Target number of buckets: " << buckets);
 872     /* ideally the full scan period should be configurable, for the
 873      * moment it remains at approximately 24 hours.  */
 874     store_hash_buckets = storeKeyHashBuckets(buckets);
 875     debugs(20, 1, "Using " << store_hash_buckets << " Store buckets");
 876     debugs(20, 1, "Max Mem  size: " << ( Config.memMaxSize >> 10) << " KB" <<
 877            (Config.memShared ? " [shared]" : ""));
 878     debugs(20, 1, "Max Swap size: " << (Store::Root().maxSize() >> 10) << " KB");
 879
 880     store_table = hash_create(storeKeyHashCmp,
 881                               store_hash_buckets, storeKeyHashHash);
 882
 883     for (int i = 0; i < Config.cacheSwap.n_configured; i++) {
 884         /* this starts a search of the store dirs, loading their
 885          * index. under the new Store api this should be
 886          * driven by the StoreHashIndex, not by each store.
 887         *
 888         * That is, the HashIndex should perform a search of each dir it is
 889         * indexing to do the hash insertions. The search is then able to
 890         * decide 'from-memory', or 'from-clean-log' or 'from-dirty-log' or
 891         * 'from-no-log'.
 892         *
 893          * Step 1: make the store rebuilds use a search internally
 894         * Step 2: change the search logic to use the four modes described
 895         *         above
 896         * Step 3: have the hash index walk the searches itself.
 897          */
 898         if (dir(i).active())
 899             store(i)->init();
 900     }
 901 }
 902
 903 uint64_t
 904 StoreHashIndex::maxSize() const
 905 {
 906     uint64_t result = 0;
 907
 908     for (int i = 0; i < Config.cacheSwap.n_configured; i++) {
 909         if (dir(i).doReportStat())
 910             result += store(i)->maxSize();
 911     }
 912
 913     return result;
 914 }
 915
 916 uint64_t
 917 StoreHashIndex::minSize() const
 918 {
 919     uint64_t result = 0;
 920
 921     for (int i = 0; i < Config.cacheSwap.n_configured; i++) {
 922         if (dir(i).doReportStat())
 923             result += store(i)->minSize();
 924     }
 925
 926     return result;
 927 }
 928
 929 uint64_t
 930 StoreHashIndex::currentSize() const
 931 {
 932     uint64_t result = 0;
 933
 934     for (int i = 0; i < Config.cacheSwap.n_configured; i++) {
 935         if (dir(i).doReportStat())
 936             result += store(i)->currentSize();
 937     }
 938
 939     return result;
 940 }
 941
 942 uint64_t
 943 StoreHashIndex::currentCount() const
 944 {
 945     uint64_t result = 0;
 946
 947     for (int i = 0; i < Config.cacheSwap.n_configured; i++) {
 948         if (dir(i).doReportStat())
 949             result += store(i)->currentCount();
 950     }
 951
 952     return result;
 953 }
 954
 955 int64_t
 956 StoreHashIndex::maxObjectSize() const
 957 {
 958     int64_t result = -1;
 959
 960     for (int i = 0; i < Config.cacheSwap.n_configured; i++) {
 961         if (dir(i).active() && store(i)->maxObjectSize() > result)
 962             result = store(i)->maxObjectSize();
 963     }
 964
 965     return result;
 966 }
 967
 968 void
 969 StoreHashIndex::stat(StoreEntry & output) const
 970 {
 971     int i;
 972
 973     /* Now go through each store, calling its stat routine */
 974
 975     for (i = 0; i < Config.cacheSwap.n_configured; i++) {
 976         storeAppendPrintf(&output, "\n");
 977         store(i)->stat(output);
 978     }
 979 }
 980
 981 void
 982 StoreHashIndex::reference(StoreEntry &e)
 983 {
 984     e.store()->reference(e);
 985 }
 986
 987 bool
 988 StoreHashIndex::dereference(StoreEntry &e)
 989 {
 990     return e.store()->dereference(e);
 991 }
 992
 993 void
 994 StoreHashIndex::maintain()
 995 {
 996     int i;
 997     /* walk each fs */
 998
 999     for (i = 0; i < Config.cacheSwap.n_configured; i++) {
1000         /* XXX FixMe: This should be done "in parallell" on the different
1001          * cache_dirs, not one at a time.
1002          */
1003         /* call the maintain function .. */
1004         store(i)->maintain();
1005     }
1006 }
1007
1008 void
1009 StoreHashIndex::sync()
1010 {
1011     for (int i = 0; i < Config.cacheSwap.n_configured; ++i)
1012         store(i)->sync();
1013 }
1014
1015 StoreSearch *
1016 StoreHashIndex::search(String const url, HttpRequest *)
1017 {
1018     if (url.size())
1019         fatal ("Cannot search by url yet\n");
1020
1021     return new StoreSearchHashIndex (this);
1022 }
1023
1024 CBDATA_CLASS_INIT(StoreSearchHashIndex);
1025
1026 StoreSearchHashIndex::StoreSearchHashIndex(RefCount<StoreHashIndex> aSwapDir) : sd(aSwapDir), _done (false), bucket (0)
1027 {}
1028
1029 /* do not link
1030 StoreSearchHashIndex::StoreSearchHashIndex(StoreSearchHashIndex const &);
1031 */
1032
1033 StoreSearchHashIndex::~StoreSearchHashIndex()
1034 {}
1035
1036 void
1037 StoreSearchHashIndex::next(void (aCallback)(void *), void *aCallbackData)
1038 {
1039     next();
1040     aCallback (aCallbackData);
1041 }
1042
1043 bool
1044 StoreSearchHashIndex::next()
1045 {
1046     if (entries.size())
1047         entries.pop_back();
1048
1049     while (!isDone() && !entries.size())
1050         copyBucket();
1051
1052     return currentItem() != NULL;
1053 }
1054
1055 bool
1056 StoreSearchHashIndex::error() const
1057 {
1058     return false;
1059 }
1060
1061 bool
1062 StoreSearchHashIndex::isDone() const
1063 {
1064     return bucket >= store_hash_buckets || _done;
1065 }
1066
1067 StoreEntry *
1068 StoreSearchHashIndex::currentItem()
1069 {
1070     if (!entries.size())
1071         return NULL;
1072
1073     return entries.back();
1074 }
1075
1076 void
1077 StoreSearchHashIndex::copyBucket()
1078 {
1079     /* probably need to lock the store entries...
1080      * we copy them all to prevent races on the links. */
1081     debugs(47, 3, "StoreSearchHashIndex::copyBucket #" << bucket);
1082     assert (!entries.size());
1083     hash_link *link_ptr = NULL;
1084     hash_link *link_next = NULL;
1085     link_next = hash_get_bucket(store_table, bucket);
1086
1087     while (NULL != (link_ptr = link_next)) {
1088         link_next = link_ptr->next;
1089         StoreEntry *e = (StoreEntry *) link_ptr;
1090
1091         entries.push_back(e);
1092     }
1093
1094     bucket++;
1095     debugs(47,3, "got entries: " << entries.size());
1096 }