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 + 1000000 ||
 192                             (info->count_chains_scanned < 1000000 &&
 193                              info->count_chains_scanned >=
 194                              info->count_chains_reported + 100000)) {
 195                                 kprintf(" chains %-7ld inodes %-7ld "
 196                                         "dirents %-7ld bytes %5ldMB\n",
 197                                         info->count_chains_scanned,
 198                                         info->count_inodes_scanned,
 199                                         info->count_dirents_scanned,
 200                                         info->count_bytes_scanned / 1000000);
 201                                 info->count_chains_reported =
 202                                         info->count_chains_scanned;
 203                         }
 204                 }
 205
 206
 207                 /*
 208                  * Else check type and setup depth-first scan.
 209                  *
 210                  * Account for bytes actually read.
 211                  */
 212                 switch(chain->bref.type) {
 213                 case HAMMER2_BREF_TYPE_INODE:
 214                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
 215                 case HAMMER2_BREF_TYPE_INDIRECT:
 216                 case HAMMER2_BREF_TYPE_VOLUME:
 217                 case HAMMER2_BREF_TYPE_FREEMAP:
 218                         ++info->depth;
 219                         if (info->depth > 16) {
 220                                 hammer2_chain_save_t *save;
 221                                 save = kmalloc(sizeof(*save), M_HAMMER2,
 222                                                M_WAITOK | M_ZERO);
 223                                 save->chain = chain;
 224                                 hammer2_chain_ref(chain);
 225                                 TAILQ_INSERT_TAIL(&info->list, save, entry);
 226
 227                                 /* guess */
 228                                 info->pri += 10;
 229                         } else {
 230                                 int savepri = info->pri;
 231
 232                                 hammer2_chain_unlock(chain);
 233                                 hammer2_chain_unlock(parent);
 234                                 info->pri = 0;
 235                                 rup_error |=
 236                                         hammer2_bulk_scan(chain, func, info);
 237                                 info->pri += savepri;
 238                                 hammer2_chain_lock(parent,
 239                                                    HAMMER2_RESOLVE_ALWAYS |
 240                                                    HAMMER2_RESOLVE_SHARED);
 241                                 hammer2_chain_lock(chain,
 242                                                    HAMMER2_RESOLVE_ALWAYS |
 243                                                    HAMMER2_RESOLVE_SHARED);
 244                         }
 245                         --info->depth;
 246                         break;
 247                 case HAMMER2_BREF_TYPE_DATA:
 248                         break;
 249                 default:
 250                         /* does not recurse */
 251                         break;
 252                 }
 253                 if (rup_error & HAMMER2_ERROR_ABORTED)
 254                         break;
 255         }
 256         if (chain) {
 257                 hammer2_chain_unlock(chain);
 258                 hammer2_chain_drop(chain);
 259         }
 260
 261         /*
 262          * Save with higher pri now that we know what it is.
 263          */
 264         h2_bulkfree_test(info, &parent->bref, info->pri + 1);
 265
 266         hammer2_chain_unlock(parent);
 267
 268         return ((error | rup_error) & ~HAMMER2_ERROR_EOF);
 269 }
 270
 271 /*
 272  * Bulkfree algorithm
 273  *
 274  * Repeat {
 275  *      Chain flush (partial synchronization) XXX removed
 276  *      Scan the whole topology - build in-memory freemap (mark 11)
 277  *      Reconcile the in-memory freemap against the on-disk freemap.
 278  *              ondisk xx -> ondisk 11 (if allocated)
 279  *              ondisk 11 -> ondisk 10 (if free in-memory)
 280  *              ondisk 10 -> ondisk 00 (if free in-memory) - on next pass
 281  * }
 282  *
 283  * The topology scan may have to be performed multiple times to window
 284  * freemaps which are too large to fit in kernel memory.
 285  *
 286  * Races are handled using a double-transition (11->10, 10->00).  The bulkfree
 287  * scan snapshots the volume root's blockset and thus can run concurrent with
 288  * normal operations, as long as a full flush is made between each pass to
 289  * synchronize any modified chains (otherwise their blocks might be improperly
 290  * freed).
 291  *
 292  * Temporary memory in multiples of 64KB is required to reconstruct the leaf
 293  * hammer2_bmap_data blocks so they can later be compared against the live
 294  * freemap.  Each 64KB block represents 128 x 16KB x 1024 = ~2 GB of storage.
 295  * A 32MB save area thus represents around ~1 TB.  The temporary memory
 296  * allocated can be specified.  If it is not sufficient multiple topology
 297  * passes will be made.
 298  */
 299
 300 /*
 301  * Bulkfree callback info
 302  */
 303 static void hammer2_bulkfree_thread(void *arg __unused);
 304 static void cbinfo_bmap_init(hammer2_bulkfree_info_t *cbinfo, size_t size);
 305 static int h2_bulkfree_callback(hammer2_bulkfree_info_t *cbinfo,
 306                         hammer2_blockref_t *bref);
 307 static int h2_bulkfree_sync(hammer2_bulkfree_info_t *cbinfo);
 308 static void h2_bulkfree_sync_adjust(hammer2_bulkfree_info_t *cbinfo,
 309                         hammer2_off_t data_off, hammer2_bmap_data_t *live,
 310                         hammer2_bmap_data_t *bmap, hammer2_key_t alloc_base);
 311
 312 void
 313 hammer2_bulkfree_init(hammer2_dev_t *hmp)
 314 {
 315         hammer2_thr_create(&hmp->bfthr, NULL, hmp,
 316                            hmp->devrepname, -1, -1,
 317                            hammer2_bulkfree_thread);
 318 }
 319
 320 void
 321 hammer2_bulkfree_uninit(hammer2_dev_t *hmp)
 322 {
 323         hammer2_thr_delete(&hmp->bfthr);
 324 }
 325
 326 static void
 327 hammer2_bulkfree_thread(void *arg)
 328 {
 329         hammer2_thread_t *thr = arg;
 330         hammer2_ioc_bulkfree_t bfi;
 331         uint32_t flags;
 332
 333         for (;;) {
 334                 hammer2_thr_wait_any(thr,
 335                                      HAMMER2_THREAD_STOP |
 336                                      HAMMER2_THREAD_FREEZE |
 337                                      HAMMER2_THREAD_UNFREEZE |
 338                                      HAMMER2_THREAD_REMASTER,
 339                                      hz * 60);
 340
 341                 flags = thr->flags;
 342                 cpu_ccfence();
 343                 if (flags & HAMMER2_THREAD_STOP)
 344                         break;
 345                 if (flags & HAMMER2_THREAD_FREEZE) {
 346                         hammer2_thr_signal2(thr, HAMMER2_THREAD_FROZEN,
 347                                                  HAMMER2_THREAD_FREEZE);
 348                         continue;
 349                 }
 350                 if (flags & HAMMER2_THREAD_UNFREEZE) {
 351                         hammer2_thr_signal2(thr, 0,
 352                                                  HAMMER2_THREAD_FROZEN |
 353                                                  HAMMER2_THREAD_UNFREEZE);
 354                         continue;
 355                 }
 356                 if (flags & HAMMER2_THREAD_FROZEN)
 357                         continue;
 358                 if (flags & HAMMER2_THREAD_REMASTER) {
 359                         hammer2_thr_signal2(thr, 0, HAMMER2_THREAD_REMASTER);
 360                         bzero(&bfi, sizeof(bfi));
 361                         bfi.size = 8192 * 1024;
 362                         /* hammer2_bulkfree_pass(thr->hmp, &bfi); */
 363                 }
 364         }
 365         thr->td = NULL;
 366         hammer2_thr_signal(thr, HAMMER2_THREAD_STOPPED);
 367         /* structure can go invalid at this point */
 368 }
 369
 370 int
 371 hammer2_bulkfree_pass(hammer2_dev_t *hmp, hammer2_chain_t *vchain,
 372                       hammer2_ioc_bulkfree_t *bfi)
 373 {
 374         hammer2_bulkfree_info_t cbinfo;
 375         hammer2_chain_save_t *save;
 376         hammer2_off_t incr;
 377         size_t size;
 378         int error;
 379
 380         /*
 381          * We have to clear the live dedup cache as it might have entries
 382          * that are freeable as of now.  Any new entries in the dedup cache
 383          * made after this point, even if they become freeable, will have
 384          * previously been fully allocated and will be protected by the
 385          * 2-stage bulkfree.
 386          */
 387         hammer2_dedup_clear(hmp);
 388
 389         /*
 390          * Setup for free pass.  Maximum buffer memory is 1/4 physical
 391          * memory.
 392          */
 393         bzero(&cbinfo, sizeof(cbinfo));
 394         size = (bfi->size + HAMMER2_FREEMAP_LEVELN_PSIZE - 1) &
 395                ~(size_t)(HAMMER2_FREEMAP_LEVELN_PSIZE - 1);
 396         if (size < 1024 * 1024)
 397                 size = 1024 * 1024;
 398         if (size > kmem_lim_size() * 1024 * 1024 / 4) {
 399                 size = kmem_lim_size() * 1024 * 1024 / 4;
 400                 kprintf("hammer2: Warning: capping bulkfree buffer at %jdM\n",
 401                         (intmax_t)size / (1024 * 1024));
 402         }
 403
 404         cbinfo.hmp = hmp;
 405         cbinfo.bmap = kmem_alloc_swapbacked(&cbinfo.kp, size, VM_SUBSYS_HAMMER);
 406         cbinfo.saved_mirror_tid = hmp->voldata.mirror_tid;
 407
 408         cbinfo.dedup = kmalloc(sizeof(*cbinfo.dedup) * HAMMER2_DEDUP_HEUR_SIZE,
 409                                M_HAMMER2, M_WAITOK | M_ZERO);
 410
 411         /*
 412          * Normalize start point to a 2GB boundary.  We operate on a
 413          * 64KB leaf bitmap boundary which represents 2GB of storage.
 414          */
 415         cbinfo.sbase = bfi->sbase;
 416         if (cbinfo.sbase > hmp->voldata.volu_size)
 417                 cbinfo.sbase = hmp->voldata.volu_size;
 418         cbinfo.sbase &= ~HAMMER2_FREEMAP_LEVEL1_MASK;
 419         TAILQ_INIT(&cbinfo.list);
 420
 421         cbinfo.bulkfree_ticks = ticks;
 422
 423         /*
 424          * Loop on a full meta-data scan as many times as required to
 425          * get through all available storage.
 426          */
 427         error = 0;
 428         while (cbinfo.sbase < hmp->voldata.volu_size) {
 429                 /*
 430                  * We have enough ram to represent (incr) bytes of storage.
 431                  * Each 64KB of ram represents 2GB of storage.
 432                  *
 433                  * We must also clean out our de-duplication heuristic for
 434                  * each (incr) bytes of storage, otherwise we wind up not
 435                  * scanning meta-data for later areas of storage because
 436                  * they had already been scanned in earlier areas of storage.
 437                  * Since the ranging is different, we have to restart
 438                  * the dedup heuristic too.
 439                  */
 440                 cbinfo_bmap_init(&cbinfo, size);
 441                 bzero(cbinfo.dedup, sizeof(*cbinfo.dedup) *
 442                                     HAMMER2_DEDUP_HEUR_SIZE);
 443                 cbinfo.count_inodes_scanned = 0;
 444                 cbinfo.count_dirents_scanned = 0;
 445                 cbinfo.count_bytes_scanned = 0;
 446                 cbinfo.count_chains_scanned = 0;
 447                 cbinfo.count_chains_reported = 0;
 448
 449                 incr = size / HAMMER2_FREEMAP_LEVELN_PSIZE *
 450                        HAMMER2_FREEMAP_LEVEL1_SIZE;
 451                 if (hmp->voldata.volu_size - cbinfo.sbase < incr)
 452                         cbinfo.sstop = hmp->voldata.volu_size;
 453                 else
 454                         cbinfo.sstop = cbinfo.sbase + incr;
 455                 kprintf("hammer2: bulkfree buf=%5jdM "
 456                         "pass %016jx-%016jx (%jdGB of media)\n",
 457                         (intmax_t)size / (1024 * 1024),
 458                         (intmax_t)cbinfo.sbase,
 459                         (intmax_t)cbinfo.sstop,
 460                         (intmax_t)incr / (1024L*1024*1024));
 461
 462                 /*
 463                  * Scan topology for stuff inside this range.
 464                  *
 465                  * NOTE - By not using a transaction the operation can
 466                  *        run concurrent with the frontend as well as
 467                  *        with flushes.
 468                  *
 469                  *        We cannot safely set a mtid without a transaction,
 470                  *        and in fact we don't want to set one anyway.  We
 471                  *        want the bulkfree to be passive and no interfere
 472                  *        with crash recovery.
 473                  */
 474 #undef HAMMER2_BULKFREE_TRANS   /* undef - don't use transaction */
 475 #ifdef HAMMER2_BULKFREE_TRANS
 476                 hammer2_trans_init(hmp->spmp, 0);
 477                 cbinfo.mtid = hammer2_trans_sub(hmp->spmp);
 478 #else
 479                 cbinfo.mtid = 0;
 480 #endif
 481                 cbinfo.pri = 0;
 482                 error |= hammer2_bulk_scan(vchain, h2_bulkfree_callback,
 483                                            &cbinfo);
 484
 485                 while ((save = TAILQ_FIRST(&cbinfo.list)) != NULL &&
 486                        error == 0) {
 487                         TAILQ_REMOVE(&cbinfo.list, save, entry);
 488                         cbinfo.pri = 0;
 489                         error |= hammer2_bulk_scan(save->chain,
 490                                                      h2_bulkfree_callback,
 491                                                      &cbinfo);
 492                         hammer2_chain_drop(save->chain);
 493                         kfree(save, M_HAMMER2);
 494                 }
 495                 while (save) {
 496                         TAILQ_REMOVE(&cbinfo.list, save, entry);
 497                         hammer2_chain_drop(save->chain);
 498                         kfree(save, M_HAMMER2);
 499                         save = TAILQ_FIRST(&cbinfo.list);
 500                 }
 501
 502                 kprintf("bulkfree lastdrop %d %d error=0x%04x\n",
 503                         vchain->refs, vchain->core.chain_count, error);
 504
 505                 /*
 506                  * If the complete scan succeeded we can synchronize our
 507                  * in-memory freemap against live storage.  If an abort
 508                  * occured we cannot safely synchronize our partially
 509                  * filled-out in-memory freemap.
 510                  */
 511                 if (error == 0) {
 512                         error = h2_bulkfree_sync(&cbinfo);
 513
 514                         hammer2_voldata_lock(hmp);
 515                         hammer2_voldata_modify(hmp);
 516                         hmp->voldata.allocator_free += cbinfo.adj_free;
 517                         hammer2_voldata_unlock(hmp);
 518                 }
 519
 520                 /*
 521                  * Cleanup for next loop.
 522                  */
 523 #ifdef HAMMER2_BULKFREE_TRANS
 524                 hammer2_trans_done(hmp->spmp, 0);
 525 #endif
 526                 if (error)
 527                         break;
 528                 cbinfo.sbase = cbinfo.sstop;
 529                 cbinfo.adj_free = 0;
 530         }
 531         kmem_free_swapbacked(&cbinfo.kp);
 532         kfree(cbinfo.dedup, M_HAMMER2);
 533         cbinfo.dedup = NULL;
 534
 535         bfi->sstop = cbinfo.sbase;
 536
 537         incr = bfi->sstop / (hmp->voldata.volu_size / 10000);
 538         if (incr > 10000)
 539                 incr = 10000;
 540
 541         kprintf("bulkfree pass statistics (%d.%02d%% storage processed):\n",
 542                 (int)incr / 100,
 543                 (int)incr % 100);
 544
 545         if (error) {
 546                 kprintf("    bulkfree was aborted\n");
 547         } else {
 548                 kprintf("    transition->free   %ld\n", cbinfo.count_10_00);
 549                 kprintf("    transition->staged %ld\n", cbinfo.count_11_10);
 550                 kprintf("    ERR(00)->allocated %ld\n", cbinfo.count_00_11);
 551                 kprintf("    ERR(01)->allocated %ld\n", cbinfo.count_01_11);
 552                 kprintf("    staged->allocated  %ld\n", cbinfo.count_10_11);
 553                 kprintf("    ~2MB segs cleaned  %ld\n", cbinfo.count_l0cleans);
 554                 kprintf("    linear adjusts     %ld\n",
 555                         cbinfo.count_linadjusts);
 556                 kprintf("    dedup factor       %ld\n",
 557                         cbinfo.count_dedup_factor);
 558         }
 559
 560         return error;
 561 }
 562
 563 static void
 564 cbinfo_bmap_init(hammer2_bulkfree_info_t *cbinfo, size_t size)
 565 {
 566         hammer2_bmap_data_t *bmap = cbinfo->bmap;
 567         hammer2_key_t key = cbinfo->sbase;
 568         hammer2_key_t lokey;
 569         hammer2_key_t hikey;
 570
 571         lokey = (cbinfo->hmp->voldata.allocator_beg + HAMMER2_SEGMASK64) &
 572                 ~HAMMER2_SEGMASK64;
 573         hikey = cbinfo->hmp->voldata.volu_size & ~HAMMER2_SEGMASK64;
 574
 575         bzero(bmap, size);
 576         while (size) {
 577                 bzero(bmap, sizeof(*bmap));
 578                 if (lokey < H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX))
 579                         lokey = H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX);
 580                 if (lokey < H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64)
 581                         lokey = H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64;
 582                 if (key < lokey || key >= hikey) {
 583                         memset(bmap->bitmapq, -1,
 584                                sizeof(bmap->bitmapq));
 585                         bmap->avail = 0;
 586                         bmap->linear = HAMMER2_SEGSIZE;
 587                 } else {
 588                         bmap->avail = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 589                 }
 590                 size -= sizeof(*bmap);
 591                 key += HAMMER2_FREEMAP_LEVEL0_SIZE;
 592                 ++bmap;
 593         }
 594 }
 595
 596 static int
 597 h2_bulkfree_callback(hammer2_bulkfree_info_t *cbinfo, hammer2_blockref_t *bref)
 598 {
 599         hammer2_bmap_data_t *bmap;
 600         hammer2_off_t data_off;
 601         uint16_t class;
 602         size_t bytes;
 603         int radix;
 604
 605         /*
 606          * Check for signal and allow yield to userland during scan.
 607          */
 608         if (hammer2_signal_check(&cbinfo->save_time))
 609                 return HAMMER2_ERROR_ABORTED;
 610
 611         /*
 612          * Deal with kernel thread cpu or I/O hogging by limiting the
 613          * number of chains scanned per second to hammer2_bulkfree_tps.
 614          * Ignore leaf records (DIRENT and DATA), no per-record I/O is
 615          * involved for those since we don't load their data.
 616          */
 617         if (bref->type != HAMMER2_BREF_TYPE_DATA &&
 618             bref->type != HAMMER2_BREF_TYPE_DIRENT) {
 619                 ++cbinfo->bulkfree_calls;
 620                 if (cbinfo->bulkfree_calls > hammer2_bulkfree_tps) {
 621                         int dticks = ticks - cbinfo->bulkfree_ticks;
 622                         if (dticks < 0)
 623                                 dticks = 0;
 624                         if (dticks < hz) {
 625                                 tsleep(&cbinfo->bulkfree_ticks, 0,
 626                                        "h2bw", hz - dticks);
 627                         }
 628                         cbinfo->bulkfree_calls = 0;
 629                         cbinfo->bulkfree_ticks = ticks;
 630                 }
 631         }
 632
 633         /*
 634          * Calculate the data offset and determine if it is within
 635          * the current freemap range being gathered.
 636          */
 637         data_off = bref->data_off & ~HAMMER2_OFF_MASK_RADIX;
 638         if (data_off < cbinfo->sbase || data_off >= cbinfo->sstop)
 639                 return 0;
 640         if (data_off < cbinfo->hmp->voldata.allocator_beg)
 641                 return 0;
 642         if (data_off >= cbinfo->hmp->voldata.volu_size)
 643                 return 0;
 644
 645         /*
 646          * Calculate the information needed to generate the in-memory
 647          * freemap record.
 648          *
 649          * Hammer2 does not allow allocations to cross the L1 (2GB) boundary,
 650          * it's a problem if it does.  (Or L0 (2MB) for that matter).
 651          */
 652         radix = (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
 653         KKASSERT(radix != 0);
 654         bytes = (size_t)1 << radix;
 655         class = (bref->type << 8) | hammer2_devblkradix(radix);
 656
 657         if (data_off + bytes > cbinfo->sstop) {
 658                 kprintf("hammer2_bulkfree_scan: illegal 2GB boundary "
 659                         "%016jx %016jx/%d\n",
 660                         (intmax_t)bref->data_off,
 661                         (intmax_t)bref->key,
 662                         bref->keybits);
 663                 bytes = cbinfo->sstop - data_off;       /* XXX */
 664         }
 665
 666         /*
 667          * Convert to a storage offset relative to the beginning of the
 668          * storage range we are collecting.  Then lookup the level0 bmap entry.
 669          */
 670         data_off -= cbinfo->sbase;
 671         bmap = cbinfo->bmap + (data_off >> HAMMER2_FREEMAP_LEVEL0_RADIX);
 672
 673         /*
 674          * Convert data_off to a bmap-relative value (~4MB storage range).
 675          * Adjust linear, class, and avail.
 676          *
 677          * Hammer2 does not allow allocations to cross the L0 (4MB) boundary,
 678          */
 679         data_off &= HAMMER2_FREEMAP_LEVEL0_MASK;
 680         if (data_off + bytes > HAMMER2_FREEMAP_LEVEL0_SIZE) {
 681                 kprintf("hammer2_bulkfree_scan: illegal 4MB boundary "
 682                         "%016jx %016jx/%d\n",
 683                         (intmax_t)bref->data_off,
 684                         (intmax_t)bref->key,
 685                         bref->keybits);
 686                 bytes = HAMMER2_FREEMAP_LEVEL0_SIZE - data_off;
 687         }
 688
 689         if (bmap->class == 0) {
 690                 bmap->class = class;
 691                 bmap->avail = HAMMER2_FREEMAP_LEVEL0_SIZE;
 692         }
 693
 694         /*
 695          * NOTE: bmap->class does not have to match class.  Classification
 696          *       is relaxed when free space is low, so some mixing can occur.
 697          */
 698 #if 0
 699         /*
 700          * XXX removed
 701          */
 702         if (bmap->class != class) {
 703                 kprintf("hammer2_bulkfree_scan: illegal mixed class "
 704                         "%016jx %016jx/%d (%04x vs %04x)\n",
 705                         (intmax_t)bref->data_off,
 706                         (intmax_t)bref->key,
 707                         bref->keybits,
 708                         class, bmap->class);
 709         }
 710 #endif
 711
 712         /*
 713          * Just record the highest byte-granular offset for now.  Do not
 714          * match against allocations which are in multiples of whole blocks.
 715          *
 716          * Make sure that any in-block linear offset at least covers the
 717          * data range.  This can cause bmap->linear to become block-aligned.
 718          */
 719         if (bytes & HAMMER2_FREEMAP_BLOCK_MASK) {
 720                 if (bmap->linear < (int32_t)data_off + (int32_t)bytes)
 721                         bmap->linear = (int32_t)data_off + (int32_t)bytes;
 722         } else if (bmap->linear >= (int32_t)data_off &&
 723                    bmap->linear < (int32_t)data_off + (int32_t)bytes) {
 724                 bmap->linear = (int32_t)data_off + (int32_t)bytes;
 725         }
 726
 727         /*
 728          * Adjust the hammer2_bitmap_t bitmap[HAMMER2_BMAP_ELEMENTS].
 729          * 64-bit entries, 2 bits per entry, to code 11.
 730          *
 731          * NOTE: data_off mask to 524288, shift right by 14 (radix for 16384),
 732          *       and multiply shift amount by 2 for sets of 2 bits.
 733          *
 734          * NOTE: The allocation can be smaller than HAMMER2_FREEMAP_BLOCK_SIZE.
 735          *       also, data_off may not be FREEMAP_BLOCK_SIZE aligned.
 736          */
 737         while (bytes > 0) {
 738                 hammer2_bitmap_t bmask;
 739                 int bindex;
 740
 741                 bindex = (int)data_off >> (HAMMER2_FREEMAP_BLOCK_RADIX +
 742                                            HAMMER2_BMAP_INDEX_RADIX);
 743                 bmask = (hammer2_bitmap_t)3 <<
 744                         ((((int)data_off & HAMMER2_BMAP_INDEX_MASK) >>
 745                          HAMMER2_FREEMAP_BLOCK_RADIX) << 1);
 746
 747                 /*
 748                  * NOTE! The (avail) calculation is bitmap-granular.  Multiple
 749                  *       sub-granular records can wind up at the same bitmap
 750                  *       position.
 751                  */
 752                 if ((bmap->bitmapq[bindex] & bmask) == 0) {
 753                         if (bytes < HAMMER2_FREEMAP_BLOCK_SIZE) {
 754                                 bmap->avail -= HAMMER2_FREEMAP_BLOCK_SIZE;
 755                         } else {
 756                                 bmap->avail -= bytes;
 757                         }
 758                         bmap->bitmapq[bindex] |= bmask;
 759                 }
 760                 data_off += HAMMER2_FREEMAP_BLOCK_SIZE;
 761                 if (bytes < HAMMER2_FREEMAP_BLOCK_SIZE)
 762                         bytes = 0;
 763                 else
 764                         bytes -= HAMMER2_FREEMAP_BLOCK_SIZE;
 765         }
 766         return 0;
 767 }
 768
 769 /*
 770  * Synchronize the in-memory bitmap with the live freemap.  This is not a
 771  * direct copy.  Instead the bitmaps must be compared:
 772  *
 773  *      In-memory       Live-freemap
 774  *         00             11 -> 10      (do nothing if live modified)
 775  *                        10 -> 00      (do nothing if live modified)
 776  *         11             10 -> 11      handles race against live
 777  *                        ** -> 11      nominally warn of corruption
 778  *
 779  * We must also fixup the hints in HAMMER2_BREF_TYPE_FREEMAP_LEAF.
 780  */
 781 static int
 782 h2_bulkfree_sync(hammer2_bulkfree_info_t *cbinfo)
 783 {
 784         hammer2_off_t data_off;
 785         hammer2_key_t key;
 786         hammer2_key_t key_dummy;
 787         hammer2_bmap_data_t *bmap;
 788         hammer2_bmap_data_t *live;
 789         hammer2_chain_t *live_parent;
 790         hammer2_chain_t *live_chain;
 791         int bmapindex;
 792         int error;
 793
 794         kprintf("hammer2_bulkfree - range ");
 795
 796         if (cbinfo->sbase < cbinfo->hmp->voldata.allocator_beg)
 797                 kprintf("%016jx-",
 798                         (intmax_t)cbinfo->hmp->voldata.allocator_beg);
 799         else
 800                 kprintf("%016jx-",
 801                         (intmax_t)cbinfo->sbase);
 802
 803         if (cbinfo->sstop > cbinfo->hmp->voldata.volu_size)
 804                 kprintf("%016jx\n",
 805                         (intmax_t)cbinfo->hmp->voldata.volu_size);
 806         else
 807                 kprintf("%016jx\n",
 808                         (intmax_t)cbinfo->sstop);
 809
 810         data_off = cbinfo->sbase;
 811         bmap = cbinfo->bmap;
 812
 813         live_parent = &cbinfo->hmp->fchain;
 814         hammer2_chain_ref(live_parent);
 815         hammer2_chain_lock(live_parent, HAMMER2_RESOLVE_ALWAYS);
 816         live_chain = NULL;
 817         error = 0;
 818
 819         /*
 820          * Iterate each hammer2_bmap_data_t line (128 bytes) managing
 821          * 4MB of storage.
 822          */
 823         while (data_off < cbinfo->sstop) {
 824                 /*
 825                  * The freemap is not used below allocator_beg or beyond
 826                  * volu_size.
 827                  */
 828
 829                 if (data_off < cbinfo->hmp->voldata.allocator_beg)
 830                         goto next;
 831                 if (data_off >= cbinfo->hmp->voldata.volu_size)
 832                         goto next;
 833
 834                 /*
 835                  * Locate the freemap leaf on the live filesystem
 836                  */
 837                 key = (data_off & ~HAMMER2_FREEMAP_LEVEL1_MASK);
 838
 839                 if (live_chain == NULL || live_chain->bref.key != key) {
 840                         if (live_chain) {
 841                                 hammer2_chain_unlock(live_chain);
 842                                 hammer2_chain_drop(live_chain);
 843                         }
 844                         live_chain = hammer2_chain_lookup(
 845                                             &live_parent,
 846                                             &key_dummy,
 847                                             key,
 848                                             key + HAMMER2_FREEMAP_LEVEL1_MASK,
 849                                             &error,
 850                                             HAMMER2_LOOKUP_ALWAYS);
 851                         if (error) {
 852                                 kprintf("hammer2_bulkfree: freemap lookup "
 853                                         "error near %016jx, error %s\n",
 854                                         (intmax_t)data_off,
 855                                         hammer2_error_str(live_chain->error));
 856                                 break;
 857                         }
 858                 }
 859                 if (live_chain == NULL) {
 860                         /*
 861                          * XXX if we implement a full recovery mode we need
 862                          * to create/recreate missing freemap chains if our
 863                          * bmap has any allocated blocks.
 864                          */
 865                         if (bmap->class &&
 866                             bmap->avail != HAMMER2_FREEMAP_LEVEL0_SIZE) {
 867                                 kprintf("hammer2_bulkfree: cannot locate "
 868                                         "live leaf for allocated data "
 869                                         "near %016jx\n",
 870                                         (intmax_t)data_off);
 871                         }
 872                         goto next;
 873                 }
 874                 if (live_chain->error) {
 875                         kprintf("hammer2_bulkfree: unable to access freemap "
 876                                 "near %016jx, error %s\n",
 877                                 (intmax_t)data_off,
 878                                 hammer2_error_str(live_chain->error));
 879                         hammer2_chain_unlock(live_chain);
 880                         hammer2_chain_drop(live_chain);
 881                         live_chain = NULL;
 882                         goto next;
 883                 }
 884
 885                 bmapindex = (data_off & HAMMER2_FREEMAP_LEVEL1_MASK) >>
 886                             HAMMER2_FREEMAP_LEVEL0_RADIX;
 887                 live = &live_chain->data->bmdata[bmapindex];
 888
 889                 /*
 890                  * Shortcut if the bitmaps match and the live linear
 891                  * indicator is sane.  We can't do a perfect check of
 892                  * live->linear because the only real requirement is that
 893                  * if it is not block-aligned, that it not cover the space
 894                  * within its current block which overlaps one of the data
 895                  * ranges we scan.  We don't retain enough fine-grained
 896                  * data in our scan to be able to set it exactly.
 897                  *
 898                  * TODO - we could shortcut this by testing that both
 899                  * live->class and bmap->class are 0, and both avails are
 900                  * set to HAMMER2_FREEMAP_LEVEL0_SIZE (4MB).
 901                  */
 902                 if (bcmp(live->bitmapq, bmap->bitmapq,
 903                          sizeof(bmap->bitmapq)) == 0 &&
 904                     live->linear >= bmap->linear) {
 905                         goto next;
 906                 }
 907                 if (hammer2_debug & 1) {
 908                         kprintf("live %016jx %04d.%04x (avail=%d)\n",
 909                                 data_off, bmapindex, live->class, live->avail);
 910                 }
 911
 912                 hammer2_chain_modify(live_chain, cbinfo->mtid, 0, 0);
 913                 live_chain->bref.check.freemap.bigmask = -1;
 914                 cbinfo->hmp->freemap_relaxed = 0;       /* reset heuristic */
 915                 live = &live_chain->data->bmdata[bmapindex];
 916
 917                 h2_bulkfree_sync_adjust(cbinfo, data_off, live, bmap,
 918                                         live_chain->bref.key +
 919                                         bmapindex *
 920                                         HAMMER2_FREEMAP_LEVEL0_SIZE);
 921 next:
 922                 data_off += HAMMER2_FREEMAP_LEVEL0_SIZE;
 923                 ++bmap;
 924         }
 925         if (live_chain) {
 926                 hammer2_chain_unlock(live_chain);
 927                 hammer2_chain_drop(live_chain);
 928         }
 929         if (live_parent) {
 930                 hammer2_chain_unlock(live_parent);
 931                 hammer2_chain_drop(live_parent);
 932         }
 933         return error;
 934 }
 935
 936 /*
 937  * Merge the bulkfree bitmap against the existing bitmap.
 938  */
 939 static
 940 void
 941 h2_bulkfree_sync_adjust(hammer2_bulkfree_info_t *cbinfo,
 942                         hammer2_off_t data_off, hammer2_bmap_data_t *live,
 943                         hammer2_bmap_data_t *bmap, hammer2_key_t alloc_base)
 944 {
 945         int bindex;
 946         int scount;
 947         hammer2_off_t tmp_off;
 948         hammer2_bitmap_t lmask;
 949         hammer2_bitmap_t mmask;
 950
 951         tmp_off = data_off;
 952
 953         for (bindex = 0; bindex < HAMMER2_BMAP_ELEMENTS; ++bindex) {
 954                 lmask = live->bitmapq[bindex];  /* live */
 955                 mmask = bmap->bitmapq[bindex];  /* snapshotted bulkfree */
 956                 if (lmask == mmask) {
 957                         tmp_off += HAMMER2_BMAP_INDEX_SIZE;
 958                         continue;
 959                 }
 960
 961                 for (scount = 0;
 962                      scount < HAMMER2_BMAP_BITS_PER_ELEMENT;
 963                      scount += 2) {
 964                         if ((mmask & 3) == 0) {
 965                                 /*
 966                                  * in-memory 00         live 11 -> 10
 967                                  *                      live 10 -> 00
 968                                  *
 969                                  * Storage might be marked allocated or
 970                                  * staged and must be remarked staged or
 971                                  * free.
 972                                  */
 973                                 switch (lmask & 3) {
 974                                 case 0: /* 00 */
 975                                         break;
 976                                 case 1: /* 01 */
 977                                         kprintf("hammer2_bulkfree: cannot "
 978                                                 "transition m=00/l=01\n");
 979                                         break;
 980                                 case 2: /* 10 -> 00 */
 981                                         live->bitmapq[bindex] &=
 982                                             ~((hammer2_bitmap_t)2 << scount);
 983                                         live->avail +=
 984                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
 985                                         if (live->avail >
 986                                             HAMMER2_FREEMAP_LEVEL0_SIZE) {
 987                                                 live->avail =
 988                                                     HAMMER2_FREEMAP_LEVEL0_SIZE;
 989                                         }
 990                                         cbinfo->adj_free +=
 991                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
 992                                         ++cbinfo->count_10_00;
 993                                         hammer2_io_dedup_assert(
 994                                                 cbinfo->hmp,
 995                                                 tmp_off |
 996                                                 HAMMER2_FREEMAP_BLOCK_RADIX,
 997                                                 HAMMER2_FREEMAP_BLOCK_SIZE);
 998                                         break;
 999                                 case 3: /* 11 -> 10 */
1000                                         live->bitmapq[bindex] &=
1001                                             ~((hammer2_bitmap_t)1 << scount);
1002                                         ++cbinfo->count_11_10;
1003                                         hammer2_io_dedup_delete(
1004                                                 cbinfo->hmp,
1005                                                 HAMMER2_BREF_TYPE_DATA,
1006                                                 tmp_off |
1007                                                 HAMMER2_FREEMAP_BLOCK_RADIX,
1008                                                 HAMMER2_FREEMAP_BLOCK_SIZE);
1009                                         break;
1010                                 }
1011                         } else if ((mmask & 3) == 3) {
1012                                 /*
1013                                  * in-memory 11         live 10 -> 11
1014                                  *                      live ** -> 11
1015                                  *
1016                                  * Storage might be incorrectly marked free
1017                                  * or staged and must be remarked fully
1018                                  * allocated.
1019                                  */
1020                                 switch (lmask & 3) {
1021                                 case 0: /* 00 */
1022                                         ++cbinfo->count_00_11;
1023                                         cbinfo->adj_free -=
1024                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1025                                         live->avail -=
1026                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1027                                         if ((int32_t)live->avail < 0)
1028                                                 live->avail = 0;
1029                                         break;
1030                                 case 1: /* 01 */
1031                                         ++cbinfo->count_01_11;
1032                                         break;
1033                                 case 2: /* 10 -> 11 */
1034                                         ++cbinfo->count_10_11;
1035                                         break;
1036                                 case 3: /* 11 */
1037                                         break;
1038                                 }
1039                                 live->bitmapq[bindex] |=
1040                                         ((hammer2_bitmap_t)3 << scount);
1041                         }
1042                         mmask >>= 2;
1043                         lmask >>= 2;
1044                         tmp_off += HAMMER2_FREEMAP_BLOCK_SIZE;
1045                 }
1046         }
1047
1048         /*
1049          * Determine if the live bitmap is completely free and reset its
1050          * fields if so.  Otherwise check to see if we can reduce the linear
1051          * offset.
1052          */
1053         for (bindex = HAMMER2_BMAP_ELEMENTS - 1; bindex >= 0; --bindex) {
1054                 if (live->bitmapq[bindex] != 0)
1055                         break;
1056         }
1057         if (bindex < 0) {
1058                 /*
1059                  * Completely empty, reset entire segment
1060                  */
1061 #if 0
1062                 kprintf("hammer2: cleanseg %016jx.%04x (%d)\n",
1063                         alloc_base, live->class, live->avail);
1064 #endif
1065                 live->avail = HAMMER2_FREEMAP_LEVEL0_SIZE;
1066                 live->class = 0;
1067                 live->linear = 0;
1068                 ++cbinfo->count_l0cleans;
1069         } else if (bindex < 7) {
1070                 /*
1071                  * Partially full, bitmapq[bindex] != 0.  The live->linear
1072                  * offset can legitimately be just about anything, but
1073                  * our bulkfree pass doesn't record enough information to
1074                  * set it exactly.  Just make sure that it is set to a
1075                  * safe value that also works in our match code above (the
1076                  * bcmp and linear test).
1077                  *
1078                  * We cannot safely leave live->linear at a sub-block offset
1079                  * unless it is already in the same block as bmap->linear.
1080                  *
1081                  * If it is not in the same block, we cannot assume that
1082                  * we can set it to bmap->linear on a sub-block boundary,
1083                  * because the live system could have bounced it around.
1084                  * In that situation we satisfy our bcmp/skip requirement
1085                  * above by setting it to the nearest higher block boundary.
1086                  * This alignment effectively kills any partial allocation it
1087                  * might have been tracking before.
1088                  */
1089                 if (live->linear < bmap->linear &&
1090                     ((live->linear ^ bmap->linear) &
1091                      ~HAMMER2_FREEMAP_BLOCK_MASK) == 0) {
1092                         live->linear = bmap->linear;
1093                         ++cbinfo->count_linadjusts;
1094                 } else {
1095                         live->linear =
1096                                 (bmap->linear + HAMMER2_FREEMAP_BLOCK_MASK) &
1097                                 ~HAMMER2_FREEMAP_BLOCK_MASK;
1098                         ++cbinfo->count_linadjusts;
1099                 }
1100         } else {
1101                 /*
1102                  * Completely full, effectively disable the linear iterator
1103                  */
1104                 live->linear = HAMMER2_SEGSIZE;
1105         }
1106
1107 #if 0
1108         if (bmap->class) {
1109                 kprintf("%016jx %04d.%04x (avail=%7d) "
1110                         "%08x %08x %08x %08x %08x %08x %08x %08x\n",
1111                         (intmax_t)data_off,
1112                         (int)((data_off &
1113                                HAMMER2_FREEMAP_LEVEL1_MASK) >>
1114                               HAMMER2_FREEMAP_LEVEL0_RADIX),
1115                         bmap->class,
1116                         bmap->avail,
1117                         bmap->bitmap[0], bmap->bitmap[1],
1118                         bmap->bitmap[2], bmap->bitmap[3],
1119                         bmap->bitmap[4], bmap->bitmap[5],
1120                         bmap->bitmap[6], bmap->bitmap[7]);
1121         }
1122 #endif
1123 }
1124
1125 /*
1126  * BULKFREE DEDUP HEURISTIC
1127  *
1128  * WARNING! This code is SMP safe but the heuristic allows SMP collisions.
1129  *          All fields must be loaded into locals and validated.
1130  */
1131 static
1132 int
1133 h2_bulkfree_test(hammer2_bulkfree_info_t *cbinfo, hammer2_blockref_t *bref,
1134                  int pri)
1135 {
1136         hammer2_dedup_t *dedup;
1137         int best;
1138         int n;
1139         int i;
1140
1141         n = hammer2_icrc32(&bref->data_off, sizeof(bref->data_off));
1142         dedup = cbinfo->dedup + (n & (HAMMER2_DEDUP_HEUR_MASK & ~7));
1143
1144         for (i = best = 0; i < 8; ++i) {
1145                 if (dedup[i].data_off == bref->data_off) {
1146                         if (dedup[i].ticks < pri)
1147                                 dedup[i].ticks = pri;
1148                         if (pri == 1)
1149                                 cbinfo->count_dedup_factor += dedup[i].ticks;
1150                         return 1;
1151                 }
1152                 if (dedup[i].ticks < dedup[best].ticks)
1153                         best = i;
1154         }
1155         dedup[best].data_off = bref->data_off;
1156         dedup[best].ticks = pri;
1157
1158         return 0;
1159 }