sys/vfs/hammer2/hammer2_bulkfree.c

   1 /*
   2  * Copyright (c) 2013-2018 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@dragonflybsd.org>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/kernel.h>
  37 #include <sys/fcntl.h>
  38 #include <sys/buf.h>
  39 #include <sys/proc.h>
  40 #include <sys/namei.h>
  41 #include <sys/mount.h>
  42 #include <sys/vnode.h>
  43 #include <sys/mountctl.h>
  44 #include <vm/vm_kern.h>
  45 #include <vm/vm_extern.h>
  46
  47 #include "hammer2.h"
  48
  49 /*
  50  * XXX I made a mistake and made the reserved area begin at each LEVEL1 zone,
  51  *     which is on a 1GB demark.  This will eat a little more space but for
  52  *     now we retain compatibility and make FMZONEBASE every 1GB
  53  */
  54 #define H2FMZONEBASE(key)         ((key) & ~HAMMER2_FREEMAP_LEVEL1_MASK)
  55 #define H2FMBASE(key, radix)    ((key) & ~(((hammer2_off_t)1 << (radix)) - 1))
  56 #define H2FMSHIFT(radix)        ((hammer2_off_t)1 << (radix))
  57
  58 /*
  59  * breadth-first search
  60  */
  61 typedef struct hammer2_chain_save {
  62         TAILQ_ENTRY(hammer2_chain_save) entry;
  63         hammer2_chain_t *chain;
  64         int pri;
  65 } hammer2_chain_save_t;
  66
  67 TAILQ_HEAD(hammer2_chain_save_list, hammer2_chain_save);
  68 typedef struct hammer2_chain_save_list hammer2_chain_save_list_t;
  69
  70 typedef struct hammer2_bulkfree_info {
  71         hammer2_dev_t           *hmp;
  72         kmem_anon_desc_t        kp;
  73         hammer2_off_t           sbase;          /* sub-loop iteration */
  74         hammer2_off_t           sstop;
  75         hammer2_bmap_data_t     *bmap;
  76         int                     depth;
  77         long                    count_10_00;    /* staged->free      */
  78         long                    count_11_10;    /* allocated->staged */
  79         long                    count_00_11;    /* (should not happen) */
  80         long                    count_01_11;    /* (should not happen) */
  81         long                    count_10_11;    /* staged->allocated */
  82         long                    count_l0cleans;
  83         long                    count_linadjusts;
  84         long                    count_inodes_scanned;
  85         long                    count_dirents_scanned;
  86         long                    count_dedup_factor;
  87         long                    count_bytes_scanned;
  88         long                    count_chains_scanned;
  89         long                    count_chains_reported;
  90         long                    bulkfree_calls;
  91         int                     bulkfree_ticks;
  92         hammer2_off_t           adj_free;
  93         hammer2_tid_t           mtid;
  94         hammer2_tid_t           saved_mirror_tid;
  95         time_t                  save_time;
  96         hammer2_chain_save_list_t list;
  97         hammer2_dedup_t         *dedup;
  98         int                     pri;
  99 } hammer2_bulkfree_info_t;
 100
 101 static int h2_bulkfree_test(hammer2_bulkfree_info_t *info,
 102                         hammer2_blockref_t *bref, int pri);
 103
 104 /*
 105  * General bulk scan function with callback.  Called with a referenced
 106  * but UNLOCKED parent.  The parent is returned in the same state.
 107  */
 108 static
 109 int
 110 hammer2_bulk_scan(hammer2_chain_t *parent,
 111                   int (*func)(hammer2_bulkfree_info_t *info,
 112                               hammer2_blockref_t *bref),
 113                   hammer2_bulkfree_info_t *info)
 114 {
 115         hammer2_blockref_t bref;
 116         hammer2_chain_t *chain;
 117         int first = 1;
 118         int rup_error;
 119         int error;
 120
 121         ++info->pri;
 122
 123         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS |
 124                                    HAMMER2_RESOLVE_SHARED);
 125         chain = NULL;
 126         rup_error = 0;
 127         error = 0;
 128
 129         /*
 130          * Generally loop on the contents if we have not been flagged
 131          * for abort.
 132          *
 133          * Remember that these chains are completely isolated from
 134          * the frontend, so we can release locks temporarily without
 135          * imploding.
 136          */
 137         for (;;) {
 138                 error |= hammer2_chain_scan(parent, &chain, &bref, &first,
 139                                             HAMMER2_LOOKUP_NODATA |
 140                                             HAMMER2_LOOKUP_SHARED);
 141
 142                 /*
 143                  * Handle EOF or other error at current level.  This stops
 144                  * the bulkfree scan.
 145                  */
 146                 if (error)
 147                         break;
 148
 149                 /*
 150                  * Account for dirents before thre data_off test, since most
 151                  * dirents do not need a data reference.
 152                  */
 153                 if (bref.type == HAMMER2_BREF_TYPE_DIRENT)
 154                         ++info->count_dirents_scanned;
 155
 156                 /*
 157                  * Ignore brefs without data (typically dirents)
 158                  */
 159                 if ((bref.data_off & ~HAMMER2_OFF_MASK_RADIX) == 0)
 160                         continue;
 161
 162                 /*
 163                  * Process bref, chain is only non-NULL if the bref
 164                  * might be recursable (its possible that we sometimes get
 165                  * a non-NULL chain where the bref cannot be recursed).
 166                  */
 167                 ++info->pri;
 168                 if (h2_bulkfree_test(info, &bref, 1))
 169                         continue;
 170
 171                 if (bref.type == HAMMER2_BREF_TYPE_INODE)
 172                         ++info->count_inodes_scanned;
 173
 174                 error |= func(info, &bref);
 175                 if (error)
 176                         break;
 177
 178                 /*
 179                  * A non-null chain is always returned if it is
 180                  * recursive, otherwise a non-null chain might be
 181                  * returned but usually is not when not recursive.
 182                  */
 183                 if (chain == NULL)
 184                         continue;
 185
 186                 if (chain) {
 187                         info->count_bytes_scanned += chain->bytes;
 188                         ++info->count_chains_scanned;
 189
 190                         if (info->count_chains_scanned >=
 191                             info->count_chains_reported + 50000) {
 192                                 kprintf(" chains %-7ld inodes %-7ld "
 193                                         "dirents %-7ld bytes %5ldMB\n",
 194                                         info->count_chains_scanned,
 195                                         info->count_inodes_scanned,
 196                                         info->count_dirents_scanned,
 197                                         info->count_bytes_scanned / 1000000);
 198                                 info->count_chains_reported += 50000;
 199                         }
 200                 }
 201
 202
 203                 /*
 204                  * Else check type and setup depth-first scan.
 205                  *
 206                  * Account for bytes actually read.
 207                  */
 208                 switch(chain->bref.type) {
 209                 case HAMMER2_BREF_TYPE_INODE:
 210                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
 211                 case HAMMER2_BREF_TYPE_INDIRECT:
 212                 case HAMMER2_BREF_TYPE_VOLUME:
 213                 case HAMMER2_BREF_TYPE_FREEMAP:
 214                         ++info->depth;
 215                         if (info->depth > 16) {
 216                                 hammer2_chain_save_t *save;
 217                                 save = kmalloc(sizeof(*save), M_HAMMER2,
 218                                                M_WAITOK | M_ZERO);
 219                                 save->chain = chain;
 220                                 hammer2_chain_ref(chain);
 221                                 TAILQ_INSERT_TAIL(&info->list, save, entry);
 222
 223                                 /* guess */
 224                                 info->pri += 10;
 225                         } else {
 226                                 int savepri = info->pri;
 227
 228                                 hammer2_chain_unlock(chain);
 229                                 hammer2_chain_unlock(parent);
 230                                 info->pri = 0;
 231                                 rup_error |=
 232                                         hammer2_bulk_scan(chain, func, info);
 233                                 info->pri += savepri;
 234                                 hammer2_chain_lock(parent,
 235                                                    HAMMER2_RESOLVE_ALWAYS |
 236                                                    HAMMER2_RESOLVE_SHARED);
 237                                 hammer2_chain_lock(chain,
 238                                                    HAMMER2_RESOLVE_ALWAYS |
 239                                                    HAMMER2_RESOLVE_SHARED);
 240                         }
 241                         --info->depth;
 242                         break;
 243                 case HAMMER2_BREF_TYPE_DATA:
 244                         break;
 245                 default:
 246                         /* does not recurse */
 247                         break;
 248                 }
 249                 if (rup_error & HAMMER2_ERROR_ABORTED)
 250                         break;
 251         }
 252         if (chain) {
 253                 hammer2_chain_unlock(chain);
 254                 hammer2_chain_drop(chain);
 255         }
 256
 257         /*
 258          * Save with higher pri now that we know what it is.
 259          */
 260         h2_bulkfree_test(info, &parent->bref, info->pri + 1);
 261
 262         hammer2_chain_unlock(parent);
 263
 264         return ((error | rup_error) & ~HAMMER2_ERROR_EOF);
 265 }
 266
 267 /*
 268  * Bulkfree algorithm
 269  *
 270  * Repeat {
 271  *      Chain flush (partial synchronization) XXX removed
 272  *      Scan the whole topology - build in-memory freemap (mark 11)
 273  *      Reconcile the in-memory freemap against the on-disk freemap.
 274  *              ondisk xx -> ondisk 11 (if allocated)
 275  *              ondisk 11 -> ondisk 10 (if free in-memory)
 276  *              ondisk 10 -> ondisk 00 (if free in-memory) - on next pass
 277  * }
 278  *
 279  * The topology scan may have to be performed multiple times to window
 280  * freemaps which are too large to fit in kernel memory.
 281  *
 282  * Races are handled using a double-transition (11->10, 10->00).  The bulkfree
 283  * scan snapshots the volume root's blockset and thus can run concurrent with
 284  * normal operations, as long as a full flush is made between each pass to
 285  * synchronize any modified chains (otherwise their blocks might be improperly
 286  * freed).
 287  *
 288  * Temporary memory in multiples of 64KB is required to reconstruct the leaf
 289  * hammer2_bmap_data blocks so they can later be compared against the live
 290  * freemap.  Each 64KB block represents 128 x 16KB x 1024 = ~2 GB of storage.
 291  * A 32MB save area thus represents around ~1 TB.  The temporary memory
 292  * allocated can be specified.  If it is not sufficient multiple topology
 293  * passes will be made.
 294  */
 295
 296 /*
 297  * Bulkfree callback info
 298  */
 299 static void hammer2_bulkfree_thread(void *arg __unused);
 300 static void cbinfo_bmap_init(hammer2_bulkfree_info_t *cbinfo, size_t size);
 301 static int h2_bulkfree_callback(hammer2_bulkfree_info_t *cbinfo,
 302                         hammer2_blockref_t *bref);
 303 static int h2_bulkfree_sync(hammer2_bulkfree_info_t *cbinfo);
 304 static void h2_bulkfree_sync_adjust(hammer2_bulkfree_info_t *cbinfo,
 305                         hammer2_off_t data_off, hammer2_bmap_data_t *live,
 306                         hammer2_bmap_data_t *bmap, hammer2_key_t alloc_base);
 307
 308 void
 309 hammer2_bulkfree_init(hammer2_dev_t *hmp)
 310 {
 311         hammer2_thr_create(&hmp->bfthr, NULL, hmp,
 312                            hmp->devrepname, -1, -1,
 313                            hammer2_bulkfree_thread);
 314 }
 315
 316 void
 317 hammer2_bulkfree_uninit(hammer2_dev_t *hmp)
 318 {
 319         hammer2_thr_delete(&hmp->bfthr);
 320 }
 321
 322 static void
 323 hammer2_bulkfree_thread(void *arg)
 324 {
 325         hammer2_thread_t *thr = arg;
 326         hammer2_ioc_bulkfree_t bfi;
 327         uint32_t flags;
 328
 329         for (;;) {
 330                 hammer2_thr_wait_any(thr,
 331                                      HAMMER2_THREAD_STOP |
 332                                      HAMMER2_THREAD_FREEZE |
 333                                      HAMMER2_THREAD_UNFREEZE |
 334                                      HAMMER2_THREAD_REMASTER,
 335                                      hz * 60);
 336
 337                 flags = thr->flags;
 338                 cpu_ccfence();
 339                 if (flags & HAMMER2_THREAD_STOP)
 340                         break;
 341                 if (flags & HAMMER2_THREAD_FREEZE) {
 342                         hammer2_thr_signal2(thr, HAMMER2_THREAD_FROZEN,
 343                                                  HAMMER2_THREAD_FREEZE);
 344                         continue;
 345                 }
 346                 if (flags & HAMMER2_THREAD_UNFREEZE) {
 347                         hammer2_thr_signal2(thr, 0,
 348                                                  HAMMER2_THREAD_FROZEN |
 349                                                  HAMMER2_THREAD_UNFREEZE);
 350                         continue;
 351                 }
 352                 if (flags & HAMMER2_THREAD_FROZEN)
 353                         continue;
 354                 if (flags & HAMMER2_THREAD_REMASTER) {
 355                         hammer2_thr_signal2(thr, 0, HAMMER2_THREAD_REMASTER);
 356                         bzero(&bfi, sizeof(bfi));
 357                         bfi.size = 8192 * 1024;
 358                         /* hammer2_bulkfree_pass(thr->hmp, &bfi); */
 359                 }
 360         }
 361         thr->td = NULL;
 362         hammer2_thr_signal(thr, HAMMER2_THREAD_STOPPED);
 363         /* structure can go invalid at this point */
 364 }
 365
 366 int
 367 hammer2_bulkfree_pass(hammer2_dev_t *hmp, hammer2_chain_t *vchain,
 368                       hammer2_ioc_bulkfree_t *bfi)
 369 {
 370         hammer2_bulkfree_info_t cbinfo;
 371         hammer2_chain_save_t *save;
 372         hammer2_off_t incr;
 373         size_t size;
 374         int error;
 375
 376         /*
 377          * We have to clear the live dedup cache as it might have entries
 378          * that are freeable as of now.  Any new entries in the dedup cache
 379          * made after this point, even if they become freeable, will have
 380          * previously been fully allocated and will be protected by the
 381          * 2-stage bulkfree.
 382          */
 383         hammer2_dedup_clear(hmp);
 384
 385         /*
 386          * Setup for free pass
 387          */
 388         bzero(&cbinfo, sizeof(cbinfo));
 389         size = (bfi->size + HAMMER2_FREEMAP_LEVELN_PSIZE - 1) &
 390                ~(size_t)(HAMMER2_FREEMAP_LEVELN_PSIZE - 1);
 391         if (size < 1024 * 1024)
 392                 size = 1024 * 1024;
 393         if (size > 64 * 1024 * 1024)
 394                 size = 64 * 1024 * 1024;
 395
 396         cbinfo.hmp = hmp;
 397         cbinfo.bmap = kmem_alloc_swapbacked(&cbinfo.kp, size, VM_SUBSYS_HAMMER);
 398         cbinfo.saved_mirror_tid = hmp->voldata.mirror_tid;
 399
 400         cbinfo.dedup = kmalloc(sizeof(*cbinfo.dedup) * HAMMER2_DEDUP_HEUR_SIZE,
 401                                M_HAMMER2, M_WAITOK | M_ZERO);
 402
 403         /*
 404          * Normalize start point to a 2GB boundary.  We operate on a
 405          * 64KB leaf bitmap boundary which represents 2GB of storage.
 406          */
 407         cbinfo.sbase = bfi->sbase;
 408         if (cbinfo.sbase > hmp->voldata.volu_size)
 409                 cbinfo.sbase = hmp->voldata.volu_size;
 410         cbinfo.sbase &= ~HAMMER2_FREEMAP_LEVEL1_MASK;
 411         TAILQ_INIT(&cbinfo.list);
 412
 413         cbinfo.bulkfree_ticks = ticks;
 414
 415         /*
 416          * Loop on a full meta-data scan as many times as required to
 417          * get through all available storage.
 418          */
 419         error = 0;
 420         while (cbinfo.sbase < hmp->voldata.volu_size) {
 421                 /*
 422                  * We have enough ram to represent (incr) bytes of storage.
 423                  * Each 64KB of ram represents 2GB of storage.
 424                  *
 425                  * We must also clean out our de-duplication heuristic for
 426                  * each (incr) bytes of storage, otherwise we wind up not
 427                  * scanning meta-data for later areas of storage because
 428                  * they had already been scanned in earlier areas of storage.
 429                  * Since the ranging is different, we have to restart
 430                  * the dedup heuristic too.
 431                  */
 432                 cbinfo_bmap_init(&cbinfo, size);
 433                 bzero(cbinfo.dedup, sizeof(*cbinfo.dedup) *
 434                                     HAMMER2_DEDUP_HEUR_SIZE);
 435                 cbinfo.count_inodes_scanned = 0;
 436                 cbinfo.count_dirents_scanned = 0;
 437                 cbinfo.count_bytes_scanned = 0;
 438                 cbinfo.count_chains_scanned = 0;
 439                 cbinfo.count_chains_reported = 0;
 440
 441                 incr = size / HAMMER2_FREEMAP_LEVELN_PSIZE *
 442                        HAMMER2_FREEMAP_LEVEL1_SIZE;
 443                 if (hmp->voldata.volu_size - cbinfo.sbase < incr)
 444                         cbinfo.sstop = hmp->voldata.volu_size;
 445                 else
 446                         cbinfo.sstop = cbinfo.sbase + incr;
 447                 if (hammer2_debug & 1) {
 448                         kprintf("bulkfree pass %016jx/%jdGB\n",
 449                                 (intmax_t)cbinfo.sbase,
 450                                 (intmax_t)incr / HAMMER2_FREEMAP_LEVEL1_SIZE);
 451                 }
 452
 453                 /*
 454                  * Scan topology for stuff inside this range.
 455                  *
 456                  * NOTE - By not using a transaction the operation can
 457                  *        run concurrent with the frontend as well as
 458                  *        with flushes.
 459                  *
 460                  *        We cannot safely set a mtid without a transaction,
 461                  *        and in fact we don't want to set one anyway.  We
 462                  *        want the bulkfree to be passive and no interfere
 463                  *        with crash recovery.
 464                  */
 465 #undef HAMMER2_BULKFREE_TRANS   /* undef - don't use transaction */
 466 #ifdef HAMMER2_BULKFREE_TRANS
 467                 hammer2_trans_init(hmp->spmp, 0);
 468                 cbinfo.mtid = hammer2_trans_sub(hmp->spmp);
 469 #else
 470                 cbinfo.mtid = 0;
 471 #endif
 472                 cbinfo.pri = 0;
 473                 error |= hammer2_bulk_scan(vchain, h2_bulkfree_callback,
 474                                            &cbinfo);
 475
 476                 while ((save = TAILQ_FIRST(&cbinfo.list)) != NULL &&
 477                        error == 0) {
 478                         TAILQ_REMOVE(&cbinfo.list, save, entry);
 479                         cbinfo.pri = 0;
 480                         error |= hammer2_bulk_scan(save->chain,
 481                                                      h2_bulkfree_callback,
 482                                                      &cbinfo);
 483                         hammer2_chain_drop(save->chain);
 484                         kfree(save, M_HAMMER2);
 485                 }
 486                 while (save) {
 487                         TAILQ_REMOVE(&cbinfo.list, save, entry);
 488                         hammer2_chain_drop(save->chain);
 489                         kfree(save, M_HAMMER2);
 490                         save = TAILQ_FIRST(&cbinfo.list);
 491                 }
 492
 493                 kprintf("bulkfree lastdrop %d %d error=0x%04x\n",
 494                         vchain->refs, vchain->core.chain_count, error);
 495
 496                 /*
 497                  * If complete scan succeeded we can synchronize our
 498                  * in-memory freemap against live storage.  If an abort
 499                  * did occur we cannot safely synchronize our partially
 500                  * filled-out in-memory freemap.
 501                  */
 502                 if (error == 0) {
 503                         error = h2_bulkfree_sync(&cbinfo);
 504
 505                         hammer2_voldata_lock(hmp);
 506                         hammer2_voldata_modify(hmp);
 507                         hmp->voldata.allocator_free += cbinfo.adj_free;
 508                         hammer2_voldata_unlock(hmp);
 509                 }
 510
 511                 /*
 512                  * Cleanup for next loop.
 513                  */
 514 #ifdef HAMMER2_BULKFREE_TRANS
 515                 hammer2_trans_done(hmp->spmp);
 516 #endif
 517                 if (error)
 518                         break;
 519                 cbinfo.sbase = cbinfo.sstop;
 520                 cbinfo.adj_free = 0;
 521         }
 522         kmem_free_swapbacked(&cbinfo.kp);
 523         kfree(cbinfo.dedup, M_HAMMER2);
 524         cbinfo.dedup = NULL;
 525
 526         bfi->sstop = cbinfo.sbase;
 527
 528         incr = bfi->sstop / (hmp->voldata.volu_size / 10000);
 529         if (incr > 10000)
 530                 incr = 10000;
 531
 532         kprintf("bulkfree pass statistics (%d.%02d%% storage processed):\n",
 533                 (int)incr / 100,
 534                 (int)incr % 100);
 535
 536         if (error) {
 537                 kprintf("    bulkfree was aborted\n");
 538         } else {
 539                 kprintf("    transition->free   %ld\n", cbinfo.count_10_00);
 540                 kprintf("    transition->staged %ld\n", cbinfo.count_11_10);
 541                 kprintf("    ERR(00)->allocated %ld\n", cbinfo.count_00_11);
 542                 kprintf("    ERR(01)->allocated %ld\n", cbinfo.count_01_11);
 543                 kprintf("    staged->allocated  %ld\n", cbinfo.count_10_11);
 544                 kprintf("    ~2MB segs cleaned  %ld\n", cbinfo.count_l0cleans);
 545                 kprintf("    linear adjusts     %ld\n",
 546                         cbinfo.count_linadjusts);
 547                 kprintf("    dedup factor       %ld\n",
 548                         cbinfo.count_dedup_factor);
 549         }
 550
 551         return error;
 552 }
 553
 554 static void
 555 cbinfo_bmap_init(hammer2_bulkfree_info_t *cbinfo, size_t size)
 556 {
 557         hammer2_bmap_data_t *bmap = cbinfo->bmap;
 558         hammer2_key_t key = cbinfo->sbase;
 559         hammer2_key_t lokey;
 560         hammer2_key_t hikey;
 561
 562         lokey = (cbinfo->hmp->voldata.allocator_beg + HAMMER2_SEGMASK64) &
 563                 ~HAMMER2_SEGMASK64;
 564         hikey = cbinfo->hmp->voldata.volu_size & ~HAMMER2_SEGMASK64;
 565
 566         bzero(bmap, size);
 567         while (size) {
 568                 bzero(bmap, sizeof(*bmap));
 569                 if (lokey < H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX))
 570                         lokey = H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX);
 571                 if (lokey < H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64)
 572                         lokey = H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64;
 573                 if (key < lokey || key >= hikey) {
 574                         memset(bmap->bitmapq, -1,
 575                                sizeof(bmap->bitmapq));
 576                         bmap->avail = 0;
 577                         bmap->linear = HAMMER2_SEGSIZE;
 578                 } else {
 579                         bmap->avail = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 580                 }
 581                 size -= sizeof(*bmap);
 582                 key += HAMMER2_FREEMAP_LEVEL0_SIZE;
 583                 ++bmap;
 584         }
 585 }
 586
 587 static int
 588 h2_bulkfree_callback(hammer2_bulkfree_info_t *cbinfo, hammer2_blockref_t *bref)
 589 {
 590         hammer2_bmap_data_t *bmap;
 591         hammer2_off_t data_off;
 592         uint16_t class;
 593         size_t bytes;
 594         int radix;
 595
 596         /*
 597          * Check for signal and allow yield to userland during scan.
 598          */
 599         if (hammer2_signal_check(&cbinfo->save_time))
 600                 return HAMMER2_ERROR_ABORTED;
 601
 602         /*
 603          * Deal with kernel thread cpu or I/O hogging by limiting the
 604          * number of chains scanned per second to hammer2_bulkfree_tps.
 605          * Ignore leaf records (DIRENT and DATA), no per-record I/O is
 606          * involved for those since we don't load their data.
 607          */
 608         if (bref->type != HAMMER2_BREF_TYPE_DATA &&
 609             bref->type != HAMMER2_BREF_TYPE_DIRENT) {
 610                 ++cbinfo->bulkfree_calls;
 611                 if (cbinfo->bulkfree_calls > hammer2_bulkfree_tps) {
 612                         int dticks = ticks - cbinfo->bulkfree_ticks;
 613                         if (dticks < 0)
 614                                 dticks = 0;
 615                         if (dticks < hz) {
 616                                 tsleep(&cbinfo->bulkfree_ticks, 0,
 617                                        "h2bw", hz - dticks);
 618                         }
 619                         cbinfo->bulkfree_calls = 0;
 620                         cbinfo->bulkfree_ticks = ticks;
 621                 }
 622         }
 623
 624         /*
 625          * Calculate the data offset and determine if it is within
 626          * the current freemap range being gathered.
 627          */
 628         data_off = bref->data_off & ~HAMMER2_OFF_MASK_RADIX;
 629         if (data_off < cbinfo->sbase || data_off >= cbinfo->sstop)
 630                 return 0;
 631         if (data_off < cbinfo->hmp->voldata.allocator_beg)
 632                 return 0;
 633         if (data_off >= cbinfo->hmp->voldata.volu_size)
 634                 return 0;
 635
 636         /*
 637          * Calculate the information needed to generate the in-memory
 638          * freemap record.
 639          *
 640          * Hammer2 does not allow allocations to cross the L1 (2GB) boundary,
 641          * it's a problem if it does.  (Or L0 (2MB) for that matter).
 642          */
 643         radix = (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
 644         KKASSERT(radix != 0);
 645         bytes = (size_t)1 << radix;
 646         class = (bref->type << 8) | hammer2_devblkradix(radix);
 647
 648         if (data_off + bytes > cbinfo->sstop) {
 649                 kprintf("hammer2_bulkfree_scan: illegal 2GB boundary "
 650                         "%016jx %016jx/%d\n",
 651                         (intmax_t)bref->data_off,
 652                         (intmax_t)bref->key,
 653                         bref->keybits);
 654                 bytes = cbinfo->sstop - data_off;       /* XXX */
 655         }
 656
 657         /*
 658          * Convert to a storage offset relative to the beginning of the
 659          * storage range we are collecting.  Then lookup the level0 bmap entry.
 660          */
 661         data_off -= cbinfo->sbase;
 662         bmap = cbinfo->bmap + (data_off >> HAMMER2_FREEMAP_LEVEL0_RADIX);
 663
 664         /*
 665          * Convert data_off to a bmap-relative value (~4MB storage range).
 666          * Adjust linear, class, and avail.
 667          *
 668          * Hammer2 does not allow allocations to cross the L0 (4MB) boundary,
 669          */
 670         data_off &= HAMMER2_FREEMAP_LEVEL0_MASK;
 671         if (data_off + bytes > HAMMER2_FREEMAP_LEVEL0_SIZE) {
 672                 kprintf("hammer2_bulkfree_scan: illegal 4MB boundary "
 673                         "%016jx %016jx/%d\n",
 674                         (intmax_t)bref->data_off,
 675                         (intmax_t)bref->key,
 676                         bref->keybits);
 677                 bytes = HAMMER2_FREEMAP_LEVEL0_SIZE - data_off;
 678         }
 679
 680         if (bmap->class == 0) {
 681                 bmap->class = class;
 682                 bmap->avail = HAMMER2_FREEMAP_LEVEL0_SIZE;
 683         }
 684
 685         /*
 686          * NOTE: bmap->class does not have to match class.  Classification
 687          *       is relaxed when free space is low, so some mixing can occur.
 688          */
 689 #if 0
 690         /*
 691          * XXX removed
 692          */
 693         if (bmap->class != class) {
 694                 kprintf("hammer2_bulkfree_scan: illegal mixed class "
 695                         "%016jx %016jx/%d (%04x vs %04x)\n",
 696                         (intmax_t)bref->data_off,
 697                         (intmax_t)bref->key,
 698                         bref->keybits,
 699                         class, bmap->class);
 700         }
 701 #endif
 702
 703         /*
 704          * Just record the highest byte-granular offset for now.  Do not
 705          * match against allocations which are in multiples of whole blocks.
 706          *
 707          * Make sure that any in-block linear offset at least covers the
 708          * data range.  This can cause bmap->linear to become block-aligned.
 709          */
 710         if (bytes & HAMMER2_FREEMAP_BLOCK_MASK) {
 711                 if (bmap->linear < (int32_t)data_off + (int32_t)bytes)
 712                         bmap->linear = (int32_t)data_off + (int32_t)bytes;
 713         } else if (bmap->linear >= (int32_t)data_off &&
 714                    bmap->linear < (int32_t)data_off + (int32_t)bytes) {
 715                 bmap->linear = (int32_t)data_off + (int32_t)bytes;
 716         }
 717
 718         /*
 719          * Adjust the hammer2_bitmap_t bitmap[HAMMER2_BMAP_ELEMENTS].
 720          * 64-bit entries, 2 bits per entry, to code 11.
 721          *
 722          * NOTE: data_off mask to 524288, shift right by 14 (radix for 16384),
 723          *       and multiply shift amount by 2 for sets of 2 bits.
 724          *
 725          * NOTE: The allocation can be smaller than HAMMER2_FREEMAP_BLOCK_SIZE.
 726          *       also, data_off may not be FREEMAP_BLOCK_SIZE aligned.
 727          */
 728         while (bytes > 0) {
 729                 hammer2_bitmap_t bmask;
 730                 int bindex;
 731
 732                 bindex = (int)data_off >> (HAMMER2_FREEMAP_BLOCK_RADIX +
 733                                            HAMMER2_BMAP_INDEX_RADIX);
 734                 bmask = (hammer2_bitmap_t)3 <<
 735                         ((((int)data_off & HAMMER2_BMAP_INDEX_MASK) >>
 736                          HAMMER2_FREEMAP_BLOCK_RADIX) << 1);
 737
 738                 /*
 739                  * NOTE! The (avail) calculation is bitmap-granular.  Multiple
 740                  *       sub-granular records can wind up at the same bitmap
 741                  *       position.
 742                  */
 743                 if ((bmap->bitmapq[bindex] & bmask) == 0) {
 744                         if (bytes < HAMMER2_FREEMAP_BLOCK_SIZE) {
 745                                 bmap->avail -= HAMMER2_FREEMAP_BLOCK_SIZE;
 746                         } else {
 747                                 bmap->avail -= bytes;
 748                         }
 749                         bmap->bitmapq[bindex] |= bmask;
 750                 }
 751                 data_off += HAMMER2_FREEMAP_BLOCK_SIZE;
 752                 if (bytes < HAMMER2_FREEMAP_BLOCK_SIZE)
 753                         bytes = 0;
 754                 else
 755                         bytes -= HAMMER2_FREEMAP_BLOCK_SIZE;
 756         }
 757         return 0;
 758 }
 759
 760 /*
 761  * Synchronize the in-memory bitmap with the live freemap.  This is not a
 762  * direct copy.  Instead the bitmaps must be compared:
 763  *
 764  *      In-memory       Live-freemap
 765  *         00             11 -> 10      (do nothing if live modified)
 766  *                        10 -> 00      (do nothing if live modified)
 767  *         11             10 -> 11      handles race against live
 768  *                        ** -> 11      nominally warn of corruption
 769  *
 770  * We must also fixup the hints in HAMMER2_BREF_TYPE_FREEMAP_LEAF.
 771  */
 772 static int
 773 h2_bulkfree_sync(hammer2_bulkfree_info_t *cbinfo)
 774 {
 775         hammer2_off_t data_off;
 776         hammer2_key_t key;
 777         hammer2_key_t key_dummy;
 778         hammer2_bmap_data_t *bmap;
 779         hammer2_bmap_data_t *live;
 780         hammer2_chain_t *live_parent;
 781         hammer2_chain_t *live_chain;
 782         int bmapindex;
 783         int error;
 784
 785         kprintf("hammer2_bulkfree - range ");
 786
 787         if (cbinfo->sbase < cbinfo->hmp->voldata.allocator_beg)
 788                 kprintf("%016jx-",
 789                         (intmax_t)cbinfo->hmp->voldata.allocator_beg);
 790         else
 791                 kprintf("%016jx-",
 792                         (intmax_t)cbinfo->sbase);
 793
 794         if (cbinfo->sstop > cbinfo->hmp->voldata.volu_size)
 795                 kprintf("%016jx\n",
 796                         (intmax_t)cbinfo->hmp->voldata.volu_size);
 797         else
 798                 kprintf("%016jx\n",
 799                         (intmax_t)cbinfo->sstop);
 800
 801         data_off = cbinfo->sbase;
 802         bmap = cbinfo->bmap;
 803
 804         live_parent = &cbinfo->hmp->fchain;
 805         hammer2_chain_ref(live_parent);
 806         hammer2_chain_lock(live_parent, HAMMER2_RESOLVE_ALWAYS);
 807         live_chain = NULL;
 808         error = 0;
 809
 810         /*
 811          * Iterate each hammer2_bmap_data_t line (128 bytes) managing
 812          * 4MB of storage.
 813          */
 814         while (data_off < cbinfo->sstop) {
 815                 /*
 816                  * The freemap is not used below allocator_beg or beyond
 817                  * volu_size.
 818                  */
 819
 820                 if (data_off < cbinfo->hmp->voldata.allocator_beg)
 821                         goto next;
 822                 if (data_off >= cbinfo->hmp->voldata.volu_size)
 823                         goto next;
 824
 825                 /*
 826                  * Locate the freemap leaf on the live filesystem
 827                  */
 828                 key = (data_off & ~HAMMER2_FREEMAP_LEVEL1_MASK);
 829
 830                 if (live_chain == NULL || live_chain->bref.key != key) {
 831                         if (live_chain) {
 832                                 hammer2_chain_unlock(live_chain);
 833                                 hammer2_chain_drop(live_chain);
 834                         }
 835                         live_chain = hammer2_chain_lookup(
 836                                             &live_parent,
 837                                             &key_dummy,
 838                                             key,
 839                                             key + HAMMER2_FREEMAP_LEVEL1_MASK,
 840                                             &error,
 841                                             HAMMER2_LOOKUP_ALWAYS);
 842                         if (error) {
 843                                 kprintf("hammer2_bulkfree: freemap lookup "
 844                                         "error near %016jx, error %s\n",
 845                                         (intmax_t)data_off,
 846                                         hammer2_error_str(live_chain->error));
 847                                 break;
 848                         }
 849                 }
 850                 if (live_chain == NULL) {
 851                         /*
 852                          * XXX if we implement a full recovery mode we need
 853                          * to create/recreate missing freemap chains if our
 854                          * bmap has any allocated blocks.
 855                          */
 856                         if (bmap->class &&
 857                             bmap->avail != HAMMER2_FREEMAP_LEVEL0_SIZE) {
 858                                 kprintf("hammer2_bulkfree: cannot locate "
 859                                         "live leaf for allocated data "
 860                                         "near %016jx\n",
 861                                         (intmax_t)data_off);
 862                         }
 863                         goto next;
 864                 }
 865                 if (live_chain->error) {
 866                         kprintf("hammer2_bulkfree: unable to access freemap "
 867                                 "near %016jx, error %s\n",
 868                                 (intmax_t)data_off,
 869                                 hammer2_error_str(live_chain->error));
 870                         hammer2_chain_unlock(live_chain);
 871                         hammer2_chain_drop(live_chain);
 872                         live_chain = NULL;
 873                         goto next;
 874                 }
 875
 876                 bmapindex = (data_off & HAMMER2_FREEMAP_LEVEL1_MASK) >>
 877                             HAMMER2_FREEMAP_LEVEL0_RADIX;
 878                 live = &live_chain->data->bmdata[bmapindex];
 879
 880                 /*
 881                  * Shortcut if the bitmaps match and the live linear
 882                  * indicator is sane.  We can't do a perfect check of
 883                  * live->linear because the only real requirement is that
 884                  * if it is not block-aligned, that it not cover the space
 885                  * within its current block which overlaps one of the data
 886                  * ranges we scan.  We don't retain enough fine-grained
 887                  * data in our scan to be able to set it exactly.
 888                  *
 889                  * TODO - we could shortcut this by testing that both
 890                  * live->class and bmap->class are 0, and both avails are
 891                  * set to HAMMER2_FREEMAP_LEVEL0_SIZE (4MB).
 892                  */
 893                 if (bcmp(live->bitmapq, bmap->bitmapq,
 894                          sizeof(bmap->bitmapq)) == 0 &&
 895                     live->linear >= bmap->linear) {
 896                         goto next;
 897                 }
 898                 if (hammer2_debug & 1) {
 899                         kprintf("live %016jx %04d.%04x (avail=%d)\n",
 900                                 data_off, bmapindex, live->class, live->avail);
 901                 }
 902
 903                 hammer2_chain_modify(live_chain, cbinfo->mtid, 0, 0);
 904                 live_chain->bref.check.freemap.bigmask = -1;
 905                 cbinfo->hmp->freemap_relaxed = 0;       /* reset heuristic */
 906                 live = &live_chain->data->bmdata[bmapindex];
 907
 908                 h2_bulkfree_sync_adjust(cbinfo, data_off, live, bmap,
 909                                         live_chain->bref.key +
 910                                         bmapindex *
 911                                         HAMMER2_FREEMAP_LEVEL0_SIZE);
 912 next:
 913                 data_off += HAMMER2_FREEMAP_LEVEL0_SIZE;
 914                 ++bmap;
 915         }
 916         if (live_chain) {
 917                 hammer2_chain_unlock(live_chain);
 918                 hammer2_chain_drop(live_chain);
 919         }
 920         if (live_parent) {
 921                 hammer2_chain_unlock(live_parent);
 922                 hammer2_chain_drop(live_parent);
 923         }
 924         return error;
 925 }
 926
 927 /*
 928  * Merge the bulkfree bitmap against the existing bitmap.
 929  */
 930 static
 931 void
 932 h2_bulkfree_sync_adjust(hammer2_bulkfree_info_t *cbinfo,
 933                         hammer2_off_t data_off, hammer2_bmap_data_t *live,
 934                         hammer2_bmap_data_t *bmap, hammer2_key_t alloc_base)
 935 {
 936         int bindex;
 937         int scount;
 938         hammer2_off_t tmp_off;
 939         hammer2_bitmap_t lmask;
 940         hammer2_bitmap_t mmask;
 941
 942         tmp_off = data_off;
 943
 944         for (bindex = 0; bindex < HAMMER2_BMAP_ELEMENTS; ++bindex) {
 945                 lmask = live->bitmapq[bindex];  /* live */
 946                 mmask = bmap->bitmapq[bindex];  /* snapshotted bulkfree */
 947                 if (lmask == mmask) {
 948                         tmp_off += HAMMER2_BMAP_INDEX_SIZE;
 949                         continue;
 950                 }
 951
 952                 for (scount = 0;
 953                      scount < HAMMER2_BMAP_BITS_PER_ELEMENT;
 954                      scount += 2) {
 955                         if ((mmask & 3) == 0) {
 956                                 /*
 957                                  * in-memory 00         live 11 -> 10
 958                                  *                      live 10 -> 00
 959                                  *
 960                                  * Storage might be marked allocated or
 961                                  * staged and must be remarked staged or
 962                                  * free.
 963                                  */
 964                                 switch (lmask & 3) {
 965                                 case 0: /* 00 */
 966                                         break;
 967                                 case 1: /* 01 */
 968                                         kprintf("hammer2_bulkfree: cannot "
 969                                                 "transition m=00/l=01\n");
 970                                         break;
 971                                 case 2: /* 10 -> 00 */
 972                                         live->bitmapq[bindex] &=
 973                                             ~((hammer2_bitmap_t)2 << scount);
 974                                         live->avail +=
 975                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
 976                                         if (live->avail >
 977                                             HAMMER2_FREEMAP_LEVEL0_SIZE) {
 978                                                 live->avail =
 979                                                     HAMMER2_FREEMAP_LEVEL0_SIZE;
 980                                         }
 981                                         cbinfo->adj_free +=
 982                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
 983                                         ++cbinfo->count_10_00;
 984                                         hammer2_io_dedup_assert(
 985                                                 cbinfo->hmp,
 986                                                 tmp_off |
 987                                                 HAMMER2_FREEMAP_BLOCK_RADIX,
 988                                                 HAMMER2_FREEMAP_BLOCK_SIZE);
 989                                         break;
 990                                 case 3: /* 11 -> 10 */
 991                                         live->bitmapq[bindex] &=
 992                                             ~((hammer2_bitmap_t)1 << scount);
 993                                         ++cbinfo->count_11_10;
 994                                         hammer2_io_dedup_delete(
 995                                                 cbinfo->hmp,
 996                                                 HAMMER2_BREF_TYPE_DATA,
 997                                                 tmp_off |
 998                                                 HAMMER2_FREEMAP_BLOCK_RADIX,
 999                                                 HAMMER2_FREEMAP_BLOCK_SIZE);
1000                                         break;
1001                                 }
1002                         } else if ((mmask & 3) == 3) {
1003                                 /*
1004                                  * in-memory 11         live 10 -> 11
1005                                  *                      live ** -> 11
1006                                  *
1007                                  * Storage might be incorrectly marked free
1008                                  * or staged and must be remarked fully
1009                                  * allocated.
1010                                  */
1011                                 switch (lmask & 3) {
1012                                 case 0: /* 00 */
1013                                         ++cbinfo->count_00_11;
1014                                         cbinfo->adj_free -=
1015                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1016                                         live->avail -=
1017                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1018                                         if ((int32_t)live->avail < 0)
1019                                                 live->avail = 0;
1020                                         break;
1021                                 case 1: /* 01 */
1022                                         ++cbinfo->count_01_11;
1023                                         break;
1024                                 case 2: /* 10 -> 11 */
1025                                         ++cbinfo->count_10_11;
1026                                         break;
1027                                 case 3: /* 11 */
1028                                         break;
1029                                 }
1030                                 live->bitmapq[bindex] |=
1031                                         ((hammer2_bitmap_t)3 << scount);
1032                         }
1033                         mmask >>= 2;
1034                         lmask >>= 2;
1035                         tmp_off += HAMMER2_FREEMAP_BLOCK_SIZE;
1036                 }
1037         }
1038
1039         /*
1040          * Determine if the live bitmap is completely free and reset its
1041          * fields if so.  Otherwise check to see if we can reduce the linear
1042          * offset.
1043          */
1044         for (bindex = HAMMER2_BMAP_ELEMENTS - 1; bindex >= 0; --bindex) {
1045                 if (live->bitmapq[bindex] != 0)
1046                         break;
1047         }
1048         if (bindex < 0) {
1049                 /*
1050                  * Completely empty, reset entire segment
1051                  */
1052 #if 0
1053                 kprintf("hammer2: cleanseg %016jx.%04x (%d)\n",
1054                         alloc_base, live->class, live->avail);
1055 #endif
1056                 live->avail = HAMMER2_FREEMAP_LEVEL0_SIZE;
1057                 live->class = 0;
1058                 live->linear = 0;
1059                 ++cbinfo->count_l0cleans;
1060         } else if (bindex < 7) {
1061                 /*
1062                  * Partially full, bitmapq[bindex] != 0.  The live->linear
1063                  * offset can legitimately be just about anything, but
1064                  * our bulkfree pass doesn't record enough information to
1065                  * set it exactly.  Just make sure that it is set to a
1066                  * safe value that also works in our match code above (the
1067                  * bcmp and linear test).
1068                  *
1069                  * We cannot safely leave live->linear at a sub-block offset
1070                  * unless it is already in the same block as bmap->linear.
1071                  *
1072                  * If it is not in the same block, we cannot assume that
1073                  * we can set it to bmap->linear on a sub-block boundary,
1074                  * because the live system could have bounced it around.
1075                  * In that situation we satisfy our bcmp/skip requirement
1076                  * above by setting it to the nearest higher block boundary.
1077                  * This alignment effectively kills any partial allocation it
1078                  * might have been tracking before.
1079                  */
1080                 if (live->linear < bmap->linear &&
1081                     ((live->linear ^ bmap->linear) &
1082                      ~HAMMER2_FREEMAP_BLOCK_MASK) == 0) {
1083                         live->linear = bmap->linear;
1084                         ++cbinfo->count_linadjusts;
1085                 } else {
1086                         live->linear =
1087                                 (bmap->linear + HAMMER2_FREEMAP_BLOCK_MASK) &
1088                                 ~HAMMER2_FREEMAP_BLOCK_MASK;
1089                         ++cbinfo->count_linadjusts;
1090                 }
1091         } else {
1092                 /*
1093                  * Completely full, effectively disable the linear iterator
1094                  */
1095                 live->linear = HAMMER2_SEGSIZE;
1096         }
1097
1098 #if 0
1099         if (bmap->class) {
1100                 kprintf("%016jx %04d.%04x (avail=%7d) "
1101                         "%08x %08x %08x %08x %08x %08x %08x %08x\n",
1102                         (intmax_t)data_off,
1103                         (int)((data_off &
1104                                HAMMER2_FREEMAP_LEVEL1_MASK) >>
1105                               HAMMER2_FREEMAP_LEVEL0_RADIX),
1106                         bmap->class,
1107                         bmap->avail,
1108                         bmap->bitmap[0], bmap->bitmap[1],
1109                         bmap->bitmap[2], bmap->bitmap[3],
1110                         bmap->bitmap[4], bmap->bitmap[5],
1111                         bmap->bitmap[6], bmap->bitmap[7]);
1112         }
1113 #endif
1114 }
1115
1116 /*
1117  * BULKFREE DEDUP HEURISTIC
1118  *
1119  * WARNING! This code is SMP safe but the heuristic allows SMP collisions.
1120  *          All fields must be loaded into locals and validated.
1121  */
1122 static
1123 int
1124 h2_bulkfree_test(hammer2_bulkfree_info_t *cbinfo, hammer2_blockref_t *bref,
1125                  int pri)
1126 {
1127         hammer2_dedup_t *dedup;
1128         int best;
1129         int n;
1130         int i;
1131
1132         n = hammer2_icrc32(&bref->data_off, sizeof(bref->data_off));
1133         dedup = cbinfo->dedup + (n & (HAMMER2_DEDUP_HEUR_MASK & ~7));
1134
1135         for (i = best = 0; i < 8; ++i) {
1136                 if (dedup[i].data_off == bref->data_off) {
1137                         if (dedup[i].ticks < pri)
1138                                 dedup[i].ticks = pri;
1139                         if (pri == 1)
1140                                 cbinfo->count_dedup_factor += dedup[i].ticks;
1141                         return 1;
1142                 }
1143                 if (dedup[i].ticks < dedup[best].ticks)
1144                         best = i;
1145         }
1146         dedup[best].data_off = bref->data_off;
1147         dedup[best].ticks = pri;
1148
1149         return 0;
1150 }