module/zfs/ddt.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
  25  */
  26
  27 #include <sys/zfs_context.h>
  28 #include <sys/spa.h>
  29 #include <sys/spa_impl.h>
  30 #include <sys/zio.h>
  31 #include <sys/ddt.h>
  32 #include <sys/zap.h>
  33 #include <sys/dmu_tx.h>
  34 #include <sys/arc.h>
  35 #include <sys/dsl_pool.h>
  36 #include <sys/zio_checksum.h>
  37 #include <sys/zio_compress.h>
  38 #include <sys/dsl_scan.h>
  39 #include <sys/abd.h>
  40
  41 static kmem_cache_t *ddt_cache;
  42 static kmem_cache_t *ddt_entry_cache;
  43
  44 /*
  45  * Enable/disable prefetching of dedup-ed blocks which are going to be freed.
  46  */
  47 int zfs_dedup_prefetch = 0;
  48
  49 static const ddt_ops_t *ddt_ops[DDT_TYPES] = {
  50         &ddt_zap_ops,
  51 };
  52
  53 static const char *ddt_class_name[DDT_CLASSES] = {
  54         "ditto",
  55         "duplicate",
  56         "unique",
  57 };
  58
  59 static void
  60 ddt_object_create(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
  61     dmu_tx_t *tx)
  62 {
  63         spa_t *spa = ddt->ddt_spa;
  64         objset_t *os = ddt->ddt_os;
  65         uint64_t *objectp = &ddt->ddt_object[type][class];
  66         boolean_t prehash = zio_checksum_table[ddt->ddt_checksum].ci_flags &
  67             ZCHECKSUM_FLAG_DEDUP;
  68         char name[DDT_NAMELEN];
  69
  70         ddt_object_name(ddt, type, class, name);
  71
  72         ASSERT(*objectp == 0);
  73         VERIFY(ddt_ops[type]->ddt_op_create(os, objectp, tx, prehash) == 0);
  74         ASSERT(*objectp != 0);
  75
  76         VERIFY(zap_add(os, DMU_POOL_DIRECTORY_OBJECT, name,
  77             sizeof (uint64_t), 1, objectp, tx) == 0);
  78
  79         VERIFY(zap_add(os, spa->spa_ddt_stat_object, name,
  80             sizeof (uint64_t), sizeof (ddt_histogram_t) / sizeof (uint64_t),
  81             &ddt->ddt_histogram[type][class], tx) == 0);
  82 }
  83
  84 static void
  85 ddt_object_destroy(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
  86     dmu_tx_t *tx)
  87 {
  88         spa_t *spa = ddt->ddt_spa;
  89         objset_t *os = ddt->ddt_os;
  90         uint64_t *objectp = &ddt->ddt_object[type][class];
  91         uint64_t count;
  92         char name[DDT_NAMELEN];
  93
  94         ddt_object_name(ddt, type, class, name);
  95
  96         ASSERT(*objectp != 0);
  97         ASSERT(ddt_histogram_empty(&ddt->ddt_histogram[type][class]));
  98         VERIFY(ddt_object_count(ddt, type, class, &count) == 0 && count == 0);
  99         VERIFY(zap_remove(os, DMU_POOL_DIRECTORY_OBJECT, name, tx) == 0);
 100         VERIFY(zap_remove(os, spa->spa_ddt_stat_object, name, tx) == 0);
 101         VERIFY(ddt_ops[type]->ddt_op_destroy(os, *objectp, tx) == 0);
 102         bzero(&ddt->ddt_object_stats[type][class], sizeof (ddt_object_t));
 103
 104         *objectp = 0;
 105 }
 106
 107 static int
 108 ddt_object_load(ddt_t *ddt, enum ddt_type type, enum ddt_class class)
 109 {
 110         ddt_object_t *ddo = &ddt->ddt_object_stats[type][class];
 111         dmu_object_info_t doi;
 112         uint64_t count;
 113         char name[DDT_NAMELEN];
 114         int error;
 115
 116         ddt_object_name(ddt, type, class, name);
 117
 118         error = zap_lookup(ddt->ddt_os, DMU_POOL_DIRECTORY_OBJECT, name,
 119             sizeof (uint64_t), 1, &ddt->ddt_object[type][class]);
 120         if (error != 0)
 121                 return (error);
 122
 123         error = zap_lookup(ddt->ddt_os, ddt->ddt_spa->spa_ddt_stat_object, name,
 124             sizeof (uint64_t), sizeof (ddt_histogram_t) / sizeof (uint64_t),
 125             &ddt->ddt_histogram[type][class]);
 126         if (error != 0)
 127                 return (error);
 128
 129         /*
 130          * Seed the cached statistics.
 131          */
 132         error = ddt_object_info(ddt, type, class, &doi);
 133         if (error)
 134                 return (error);
 135
 136         error = ddt_object_count(ddt, type, class, &count);
 137         if (error)
 138                 return (error);
 139
 140         ddo->ddo_count = count;
 141         ddo->ddo_dspace = doi.doi_physical_blocks_512 << 9;
 142         ddo->ddo_mspace = doi.doi_fill_count * doi.doi_data_block_size;
 143
 144         return (0);
 145 }
 146
 147 static void
 148 ddt_object_sync(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
 149     dmu_tx_t *tx)
 150 {
 151         ddt_object_t *ddo = &ddt->ddt_object_stats[type][class];
 152         dmu_object_info_t doi;
 153         uint64_t count;
 154         char name[DDT_NAMELEN];
 155
 156         ddt_object_name(ddt, type, class, name);
 157
 158         VERIFY(zap_update(ddt->ddt_os, ddt->ddt_spa->spa_ddt_stat_object, name,
 159             sizeof (uint64_t), sizeof (ddt_histogram_t) / sizeof (uint64_t),
 160             &ddt->ddt_histogram[type][class], tx) == 0);
 161
 162         /*
 163          * Cache DDT statistics; this is the only time they'll change.
 164          */
 165         VERIFY(ddt_object_info(ddt, type, class, &doi) == 0);
 166         VERIFY(ddt_object_count(ddt, type, class, &count) == 0);
 167
 168         ddo->ddo_count = count;
 169         ddo->ddo_dspace = doi.doi_physical_blocks_512 << 9;
 170         ddo->ddo_mspace = doi.doi_fill_count * doi.doi_data_block_size;
 171 }
 172
 173 static int
 174 ddt_object_lookup(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
 175     ddt_entry_t *dde)
 176 {
 177         if (!ddt_object_exists(ddt, type, class))
 178                 return (SET_ERROR(ENOENT));
 179
 180         return (ddt_ops[type]->ddt_op_lookup(ddt->ddt_os,
 181             ddt->ddt_object[type][class], dde));
 182 }
 183
 184 static void
 185 ddt_object_prefetch(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
 186     ddt_entry_t *dde)
 187 {
 188         if (!ddt_object_exists(ddt, type, class))
 189                 return;
 190
 191         ddt_ops[type]->ddt_op_prefetch(ddt->ddt_os,
 192             ddt->ddt_object[type][class], dde);
 193 }
 194
 195 int
 196 ddt_object_update(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
 197     ddt_entry_t *dde, dmu_tx_t *tx)
 198 {
 199         ASSERT(ddt_object_exists(ddt, type, class));
 200
 201         return (ddt_ops[type]->ddt_op_update(ddt->ddt_os,
 202             ddt->ddt_object[type][class], dde, tx));
 203 }
 204
 205 static int
 206 ddt_object_remove(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
 207     ddt_entry_t *dde, dmu_tx_t *tx)
 208 {
 209         ASSERT(ddt_object_exists(ddt, type, class));
 210
 211         return (ddt_ops[type]->ddt_op_remove(ddt->ddt_os,
 212             ddt->ddt_object[type][class], dde, tx));
 213 }
 214
 215 int
 216 ddt_object_walk(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
 217     uint64_t *walk, ddt_entry_t *dde)
 218 {
 219         ASSERT(ddt_object_exists(ddt, type, class));
 220
 221         return (ddt_ops[type]->ddt_op_walk(ddt->ddt_os,
 222             ddt->ddt_object[type][class], dde, walk));
 223 }
 224
 225 int
 226 ddt_object_count(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
 227     uint64_t *count)
 228 {
 229         ASSERT(ddt_object_exists(ddt, type, class));
 230
 231         return (ddt_ops[type]->ddt_op_count(ddt->ddt_os,
 232             ddt->ddt_object[type][class], count));
 233 }
 234
 235 int
 236 ddt_object_info(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
 237     dmu_object_info_t *doi)
 238 {
 239         if (!ddt_object_exists(ddt, type, class))
 240                 return (SET_ERROR(ENOENT));
 241
 242         return (dmu_object_info(ddt->ddt_os, ddt->ddt_object[type][class],
 243             doi));
 244 }
 245
 246 boolean_t
 247 ddt_object_exists(ddt_t *ddt, enum ddt_type type, enum ddt_class class)
 248 {
 249         return (!!ddt->ddt_object[type][class]);
 250 }
 251
 252 void
 253 ddt_object_name(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
 254     char *name)
 255 {
 256         (void) snprintf(name, DDT_NAMELEN, DMU_POOL_DDT,
 257             zio_checksum_table[ddt->ddt_checksum].ci_name,
 258             ddt_ops[type]->ddt_op_name, ddt_class_name[class]);
 259 }
 260
 261 void
 262 ddt_bp_fill(const ddt_phys_t *ddp, blkptr_t *bp, uint64_t txg)
 263 {
 264         ASSERT(txg != 0);
 265
 266         for (int d = 0; d < SPA_DVAS_PER_BP; d++)
 267                 bp->blk_dva[d] = ddp->ddp_dva[d];
 268         BP_SET_BIRTH(bp, txg, ddp->ddp_phys_birth);
 269 }
 270
 271 /*
 272  * The bp created via this function may be used for repairs and scrub, but it
 273  * will be missing the salt / IV required to do a full decrypting read.
 274  */
 275 void
 276 ddt_bp_create(enum zio_checksum checksum,
 277     const ddt_key_t *ddk, const ddt_phys_t *ddp, blkptr_t *bp)
 278 {
 279         BP_ZERO(bp);
 280
 281         if (ddp != NULL)
 282                 ddt_bp_fill(ddp, bp, ddp->ddp_phys_birth);
 283
 284         bp->blk_cksum = ddk->ddk_cksum;
 285
 286         BP_SET_LSIZE(bp, DDK_GET_LSIZE(ddk));
 287         BP_SET_PSIZE(bp, DDK_GET_PSIZE(ddk));
 288         BP_SET_COMPRESS(bp, DDK_GET_COMPRESS(ddk));
 289         BP_SET_CRYPT(bp, DDK_GET_CRYPT(ddk));
 290         BP_SET_FILL(bp, 1);
 291         BP_SET_CHECKSUM(bp, checksum);
 292         BP_SET_TYPE(bp, DMU_OT_DEDUP);
 293         BP_SET_LEVEL(bp, 0);
 294         BP_SET_DEDUP(bp, 1);
 295         BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
 296 }
 297
 298 void
 299 ddt_key_fill(ddt_key_t *ddk, const blkptr_t *bp)
 300 {
 301         ddk->ddk_cksum = bp->blk_cksum;
 302         ddk->ddk_prop = 0;
 303
 304         ASSERT(BP_IS_ENCRYPTED(bp) || !BP_USES_CRYPT(bp));
 305
 306         DDK_SET_LSIZE(ddk, BP_GET_LSIZE(bp));
 307         DDK_SET_PSIZE(ddk, BP_GET_PSIZE(bp));
 308         DDK_SET_COMPRESS(ddk, BP_GET_COMPRESS(bp));
 309         DDK_SET_CRYPT(ddk, BP_USES_CRYPT(bp));
 310 }
 311
 312 void
 313 ddt_phys_fill(ddt_phys_t *ddp, const blkptr_t *bp)
 314 {
 315         ASSERT(ddp->ddp_phys_birth == 0);
 316
 317         for (int d = 0; d < SPA_DVAS_PER_BP; d++)
 318                 ddp->ddp_dva[d] = bp->blk_dva[d];
 319         ddp->ddp_phys_birth = BP_PHYSICAL_BIRTH(bp);
 320 }
 321
 322 void
 323 ddt_phys_clear(ddt_phys_t *ddp)
 324 {
 325         bzero(ddp, sizeof (*ddp));
 326 }
 327
 328 void
 329 ddt_phys_addref(ddt_phys_t *ddp)
 330 {
 331         ddp->ddp_refcnt++;
 332 }
 333
 334 void
 335 ddt_phys_decref(ddt_phys_t *ddp)
 336 {
 337         if (ddp) {
 338                 ASSERT(ddp->ddp_refcnt > 0);
 339                 ddp->ddp_refcnt--;
 340         }
 341 }
 342
 343 void
 344 ddt_phys_free(ddt_t *ddt, ddt_key_t *ddk, ddt_phys_t *ddp, uint64_t txg)
 345 {
 346         blkptr_t blk;
 347
 348         ddt_bp_create(ddt->ddt_checksum, ddk, ddp, &blk);
 349
 350         /*
 351          * We clear the dedup bit so that zio_free() will actually free the
 352          * space, rather than just decrementing the refcount in the DDT.
 353          */
 354         BP_SET_DEDUP(&blk, 0);
 355
 356         ddt_phys_clear(ddp);
 357         zio_free(ddt->ddt_spa, txg, &blk);
 358 }
 359
 360 ddt_phys_t *
 361 ddt_phys_select(const ddt_entry_t *dde, const blkptr_t *bp)
 362 {
 363         ddt_phys_t *ddp = (ddt_phys_t *)dde->dde_phys;
 364
 365         for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
 366                 if (DVA_EQUAL(BP_IDENTITY(bp), &ddp->ddp_dva[0]) &&
 367                     BP_PHYSICAL_BIRTH(bp) == ddp->ddp_phys_birth)
 368                         return (ddp);
 369         }
 370         return (NULL);
 371 }
 372
 373 uint64_t
 374 ddt_phys_total_refcnt(const ddt_entry_t *dde)
 375 {
 376         uint64_t refcnt = 0;
 377
 378         for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++)
 379                 refcnt += dde->dde_phys[p].ddp_refcnt;
 380
 381         return (refcnt);
 382 }
 383
 384 static void
 385 ddt_stat_generate(ddt_t *ddt, ddt_entry_t *dde, ddt_stat_t *dds)
 386 {
 387         spa_t *spa = ddt->ddt_spa;
 388         ddt_phys_t *ddp = dde->dde_phys;
 389         ddt_key_t *ddk = &dde->dde_key;
 390         uint64_t lsize = DDK_GET_LSIZE(ddk);
 391         uint64_t psize = DDK_GET_PSIZE(ddk);
 392
 393         bzero(dds, sizeof (*dds));
 394
 395         for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
 396                 uint64_t dsize = 0;
 397                 uint64_t refcnt = ddp->ddp_refcnt;
 398
 399                 if (ddp->ddp_phys_birth == 0)
 400                         continue;
 401
 402                 for (int d = 0; d < DDE_GET_NDVAS(dde); d++)
 403                         dsize += dva_get_dsize_sync(spa, &ddp->ddp_dva[d]);
 404
 405                 dds->dds_blocks += 1;
 406                 dds->dds_lsize += lsize;
 407                 dds->dds_psize += psize;
 408                 dds->dds_dsize += dsize;
 409
 410                 dds->dds_ref_blocks += refcnt;
 411                 dds->dds_ref_lsize += lsize * refcnt;
 412                 dds->dds_ref_psize += psize * refcnt;
 413                 dds->dds_ref_dsize += dsize * refcnt;
 414         }
 415 }
 416
 417 void
 418 ddt_stat_add(ddt_stat_t *dst, const ddt_stat_t *src, uint64_t neg)
 419 {
 420         const uint64_t *s = (const uint64_t *)src;
 421         uint64_t *d = (uint64_t *)dst;
 422         uint64_t *d_end = (uint64_t *)(dst + 1);
 423
 424         ASSERT(neg == 0 || neg == -1ULL);       /* add or subtract */
 425
 426         for (int i = 0; i < d_end - d; i++)
 427                 d[i] += (s[i] ^ neg) - neg;
 428 }
 429
 430 static void
 431 ddt_stat_update(ddt_t *ddt, ddt_entry_t *dde, uint64_t neg)
 432 {
 433         ddt_stat_t dds;
 434         ddt_histogram_t *ddh;
 435         int bucket;
 436
 437         ddt_stat_generate(ddt, dde, &dds);
 438
 439         bucket = highbit64(dds.dds_ref_blocks) - 1;
 440         ASSERT(bucket >= 0);
 441
 442         ddh = &ddt->ddt_histogram[dde->dde_type][dde->dde_class];
 443
 444         ddt_stat_add(&ddh->ddh_stat[bucket], &dds, neg);
 445 }
 446
 447 void
 448 ddt_histogram_add(ddt_histogram_t *dst, const ddt_histogram_t *src)
 449 {
 450         for (int h = 0; h < 64; h++)
 451                 ddt_stat_add(&dst->ddh_stat[h], &src->ddh_stat[h], 0);
 452 }
 453
 454 void
 455 ddt_histogram_stat(ddt_stat_t *dds, const ddt_histogram_t *ddh)
 456 {
 457         bzero(dds, sizeof (*dds));
 458
 459         for (int h = 0; h < 64; h++)
 460                 ddt_stat_add(dds, &ddh->ddh_stat[h], 0);
 461 }
 462
 463 boolean_t
 464 ddt_histogram_empty(const ddt_histogram_t *ddh)
 465 {
 466         const uint64_t *s = (const uint64_t *)ddh;
 467         const uint64_t *s_end = (const uint64_t *)(ddh + 1);
 468
 469         while (s < s_end)
 470                 if (*s++ != 0)
 471                         return (B_FALSE);
 472
 473         return (B_TRUE);
 474 }
 475
 476 void
 477 ddt_get_dedup_object_stats(spa_t *spa, ddt_object_t *ddo_total)
 478 {
 479         /* Sum the statistics we cached in ddt_object_sync(). */
 480         for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
 481                 ddt_t *ddt = spa->spa_ddt[c];
 482                 for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
 483                         for (enum ddt_class class = 0; class < DDT_CLASSES;
 484                             class++) {
 485                                 ddt_object_t *ddo =
 486                                     &ddt->ddt_object_stats[type][class];
 487                                 ddo_total->ddo_count += ddo->ddo_count;
 488                                 ddo_total->ddo_dspace += ddo->ddo_dspace;
 489                                 ddo_total->ddo_mspace += ddo->ddo_mspace;
 490                         }
 491                 }
 492         }
 493
 494         /* ... and compute the averages. */
 495         if (ddo_total->ddo_count != 0) {
 496                 ddo_total->ddo_dspace /= ddo_total->ddo_count;
 497                 ddo_total->ddo_mspace /= ddo_total->ddo_count;
 498         }
 499 }
 500
 501 void
 502 ddt_get_dedup_histogram(spa_t *spa, ddt_histogram_t *ddh)
 503 {
 504         for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
 505                 ddt_t *ddt = spa->spa_ddt[c];
 506                 for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
 507                         for (enum ddt_class class = 0; class < DDT_CLASSES;
 508                             class++) {
 509                                 ddt_histogram_add(ddh,
 510                                     &ddt->ddt_histogram_cache[type][class]);
 511                         }
 512                 }
 513         }
 514 }
 515
 516 void
 517 ddt_get_dedup_stats(spa_t *spa, ddt_stat_t *dds_total)
 518 {
 519         ddt_histogram_t *ddh_total;
 520
 521         ddh_total = kmem_zalloc(sizeof (ddt_histogram_t), KM_SLEEP);
 522         ddt_get_dedup_histogram(spa, ddh_total);
 523         ddt_histogram_stat(dds_total, ddh_total);
 524         kmem_free(ddh_total, sizeof (ddt_histogram_t));
 525 }
 526
 527 uint64_t
 528 ddt_get_dedup_dspace(spa_t *spa)
 529 {
 530         ddt_stat_t dds_total;
 531
 532         if (spa->spa_dedup_dspace != ~0ULL)
 533                 return (spa->spa_dedup_dspace);
 534
 535         bzero(&dds_total, sizeof (ddt_stat_t));
 536
 537         /* Calculate and cache the stats */
 538         ddt_get_dedup_stats(spa, &dds_total);
 539         spa->spa_dedup_dspace = dds_total.dds_ref_dsize - dds_total.dds_dsize;
 540         return (spa->spa_dedup_dspace);
 541 }
 542
 543 uint64_t
 544 ddt_get_pool_dedup_ratio(spa_t *spa)
 545 {
 546         ddt_stat_t dds_total = { 0 };
 547
 548         ddt_get_dedup_stats(spa, &dds_total);
 549         if (dds_total.dds_dsize == 0)
 550                 return (100);
 551
 552         return (dds_total.dds_ref_dsize * 100 / dds_total.dds_dsize);
 553 }
 554
 555 size_t
 556 ddt_compress(void *src, uchar_t *dst, size_t s_len, size_t d_len)
 557 {
 558         uchar_t *version = dst++;
 559         int cpfunc = ZIO_COMPRESS_ZLE;
 560         zio_compress_info_t *ci = &zio_compress_table[cpfunc];
 561         size_t c_len;
 562
 563         ASSERT(d_len >= s_len + 1);     /* no compression plus version byte */
 564
 565         c_len = ci->ci_compress(src, dst, s_len, d_len - 1, ci->ci_level);
 566
 567         if (c_len == s_len) {
 568                 cpfunc = ZIO_COMPRESS_OFF;
 569                 bcopy(src, dst, s_len);
 570         }
 571
 572         *version = cpfunc;
 573         /* CONSTCOND */
 574         if (ZFS_HOST_BYTEORDER)
 575                 *version |= DDT_COMPRESS_BYTEORDER_MASK;
 576
 577         return (c_len + 1);
 578 }
 579
 580 void
 581 ddt_decompress(uchar_t *src, void *dst, size_t s_len, size_t d_len)
 582 {
 583         uchar_t version = *src++;
 584         int cpfunc = version & DDT_COMPRESS_FUNCTION_MASK;
 585         zio_compress_info_t *ci = &zio_compress_table[cpfunc];
 586
 587         if (ci->ci_decompress != NULL)
 588                 (void) ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level);
 589         else
 590                 bcopy(src, dst, d_len);
 591
 592         if (((version & DDT_COMPRESS_BYTEORDER_MASK) != 0) !=
 593             (ZFS_HOST_BYTEORDER != 0))
 594                 byteswap_uint64_array(dst, d_len);
 595 }
 596
 597 ddt_t *
 598 ddt_select(spa_t *spa, const blkptr_t *bp)
 599 {
 600         return (spa->spa_ddt[BP_GET_CHECKSUM(bp)]);
 601 }
 602
 603 void
 604 ddt_enter(ddt_t *ddt)
 605 {
 606         mutex_enter(&ddt->ddt_lock);
 607 }
 608
 609 void
 610 ddt_exit(ddt_t *ddt)
 611 {
 612         mutex_exit(&ddt->ddt_lock);
 613 }
 614
 615 void
 616 ddt_init(void)
 617 {
 618         ddt_cache = kmem_cache_create("ddt_cache",
 619             sizeof (ddt_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
 620         ddt_entry_cache = kmem_cache_create("ddt_entry_cache",
 621             sizeof (ddt_entry_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
 622 }
 623
 624 void
 625 ddt_fini(void)
 626 {
 627         kmem_cache_destroy(ddt_entry_cache);
 628         kmem_cache_destroy(ddt_cache);
 629 }
 630
 631 static ddt_entry_t *
 632 ddt_alloc(const ddt_key_t *ddk)
 633 {
 634         ddt_entry_t *dde;
 635
 636         dde = kmem_cache_alloc(ddt_entry_cache, KM_SLEEP);
 637         bzero(dde, sizeof (ddt_entry_t));
 638         cv_init(&dde->dde_cv, NULL, CV_DEFAULT, NULL);
 639
 640         dde->dde_key = *ddk;
 641
 642         return (dde);
 643 }
 644
 645 static void
 646 ddt_free(ddt_entry_t *dde)
 647 {
 648         ASSERT(!dde->dde_loading);
 649
 650         for (int p = 0; p < DDT_PHYS_TYPES; p++)
 651                 ASSERT(dde->dde_lead_zio[p] == NULL);
 652
 653         if (dde->dde_repair_abd != NULL)
 654                 abd_free(dde->dde_repair_abd);
 655
 656         cv_destroy(&dde->dde_cv);
 657         kmem_cache_free(ddt_entry_cache, dde);
 658 }
 659
 660 void
 661 ddt_remove(ddt_t *ddt, ddt_entry_t *dde)
 662 {
 663         ASSERT(MUTEX_HELD(&ddt->ddt_lock));
 664
 665         avl_remove(&ddt->ddt_tree, dde);
 666         ddt_free(dde);
 667 }
 668
 669 ddt_entry_t *
 670 ddt_lookup(ddt_t *ddt, const blkptr_t *bp, boolean_t add)
 671 {
 672         ddt_entry_t *dde, dde_search;
 673         enum ddt_type type;
 674         enum ddt_class class;
 675         avl_index_t where;
 676         int error;
 677
 678         ASSERT(MUTEX_HELD(&ddt->ddt_lock));
 679
 680         ddt_key_fill(&dde_search.dde_key, bp);
 681
 682         dde = avl_find(&ddt->ddt_tree, &dde_search, &where);
 683         if (dde == NULL) {
 684                 if (!add)
 685                         return (NULL);
 686                 dde = ddt_alloc(&dde_search.dde_key);
 687                 avl_insert(&ddt->ddt_tree, dde, where);
 688         }
 689
 690         while (dde->dde_loading)
 691                 cv_wait(&dde->dde_cv, &ddt->ddt_lock);
 692
 693         if (dde->dde_loaded)
 694                 return (dde);
 695
 696         dde->dde_loading = B_TRUE;
 697
 698         ddt_exit(ddt);
 699
 700         error = ENOENT;
 701
 702         for (type = 0; type < DDT_TYPES; type++) {
 703                 for (class = 0; class < DDT_CLASSES; class++) {
 704                         error = ddt_object_lookup(ddt, type, class, dde);
 705                         if (error != ENOENT) {
 706                                 ASSERT0(error);
 707                                 break;
 708                         }
 709                 }
 710                 if (error != ENOENT)
 711                         break;
 712         }
 713
 714         ddt_enter(ddt);
 715
 716         ASSERT(dde->dde_loaded == B_FALSE);
 717         ASSERT(dde->dde_loading == B_TRUE);
 718
 719         dde->dde_type = type;   /* will be DDT_TYPES if no entry found */
 720         dde->dde_class = class; /* will be DDT_CLASSES if no entry found */
 721         dde->dde_loaded = B_TRUE;
 722         dde->dde_loading = B_FALSE;
 723
 724         if (error == 0)
 725                 ddt_stat_update(ddt, dde, -1ULL);
 726
 727         cv_broadcast(&dde->dde_cv);
 728
 729         return (dde);
 730 }
 731
 732 void
 733 ddt_prefetch(spa_t *spa, const blkptr_t *bp)
 734 {
 735         ddt_t *ddt;
 736         ddt_entry_t dde;
 737
 738         if (!zfs_dedup_prefetch || bp == NULL || !BP_GET_DEDUP(bp))
 739                 return;
 740
 741         /*
 742          * We only remove the DDT once all tables are empty and only
 743          * prefetch dedup blocks when there are entries in the DDT.
 744          * Thus no locking is required as the DDT can't disappear on us.
 745          */
 746         ddt = ddt_select(spa, bp);
 747         ddt_key_fill(&dde.dde_key, bp);
 748
 749         for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
 750                 for (enum ddt_class class = 0; class < DDT_CLASSES; class++) {
 751                         ddt_object_prefetch(ddt, type, class, &dde);
 752                 }
 753         }
 754 }
 755
 756 /*
 757  * Opaque struct used for ddt_key comparison
 758  */
 759 #define DDT_KEY_CMP_LEN (sizeof (ddt_key_t) / sizeof (uint16_t))
 760
 761 typedef struct ddt_key_cmp {
 762         uint16_t        u16[DDT_KEY_CMP_LEN];
 763 } ddt_key_cmp_t;
 764
 765 int
 766 ddt_entry_compare(const void *x1, const void *x2)
 767 {
 768         const ddt_entry_t *dde1 = x1;
 769         const ddt_entry_t *dde2 = x2;
 770         const ddt_key_cmp_t *k1 = (const ddt_key_cmp_t *)&dde1->dde_key;
 771         const ddt_key_cmp_t *k2 = (const ddt_key_cmp_t *)&dde2->dde_key;
 772         int32_t cmp = 0;
 773
 774         for (int i = 0; i < DDT_KEY_CMP_LEN; i++) {
 775                 cmp = (int32_t)k1->u16[i] - (int32_t)k2->u16[i];
 776                 if (likely(cmp))
 777                         break;
 778         }
 779
 780         return (TREE_ISIGN(cmp));
 781 }
 782
 783 static ddt_t *
 784 ddt_table_alloc(spa_t *spa, enum zio_checksum c)
 785 {
 786         ddt_t *ddt;
 787
 788         ddt = kmem_cache_alloc(ddt_cache, KM_SLEEP);
 789         bzero(ddt, sizeof (ddt_t));
 790
 791         mutex_init(&ddt->ddt_lock, NULL, MUTEX_DEFAULT, NULL);
 792         avl_create(&ddt->ddt_tree, ddt_entry_compare,
 793             sizeof (ddt_entry_t), offsetof(ddt_entry_t, dde_node));
 794         avl_create(&ddt->ddt_repair_tree, ddt_entry_compare,
 795             sizeof (ddt_entry_t), offsetof(ddt_entry_t, dde_node));
 796         ddt->ddt_checksum = c;
 797         ddt->ddt_spa = spa;
 798         ddt->ddt_os = spa->spa_meta_objset;
 799
 800         return (ddt);
 801 }
 802
 803 static void
 804 ddt_table_free(ddt_t *ddt)
 805 {
 806         ASSERT(avl_numnodes(&ddt->ddt_tree) == 0);
 807         ASSERT(avl_numnodes(&ddt->ddt_repair_tree) == 0);
 808         avl_destroy(&ddt->ddt_tree);
 809         avl_destroy(&ddt->ddt_repair_tree);
 810         mutex_destroy(&ddt->ddt_lock);
 811         kmem_cache_free(ddt_cache, ddt);
 812 }
 813
 814 void
 815 ddt_create(spa_t *spa)
 816 {
 817         spa->spa_dedup_checksum = ZIO_DEDUPCHECKSUM;
 818
 819         for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++)
 820                 spa->spa_ddt[c] = ddt_table_alloc(spa, c);
 821 }
 822
 823 int
 824 ddt_load(spa_t *spa)
 825 {
 826         int error;
 827
 828         ddt_create(spa);
 829
 830         error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
 831             DMU_POOL_DDT_STATS, sizeof (uint64_t), 1,
 832             &spa->spa_ddt_stat_object);
 833
 834         if (error)
 835                 return (error == ENOENT ? 0 : error);
 836
 837         for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
 838                 ddt_t *ddt = spa->spa_ddt[c];
 839                 for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
 840                         for (enum ddt_class class = 0; class < DDT_CLASSES;
 841                             class++) {
 842                                 error = ddt_object_load(ddt, type, class);
 843                                 if (error != 0 && error != ENOENT)
 844                                         return (error);
 845                         }
 846                 }
 847
 848                 /*
 849                  * Seed the cached histograms.
 850                  */
 851                 bcopy(ddt->ddt_histogram, &ddt->ddt_histogram_cache,
 852                     sizeof (ddt->ddt_histogram));
 853                 spa->spa_dedup_dspace = ~0ULL;
 854         }
 855
 856         return (0);
 857 }
 858
 859 void
 860 ddt_unload(spa_t *spa)
 861 {
 862         for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
 863                 if (spa->spa_ddt[c]) {
 864                         ddt_table_free(spa->spa_ddt[c]);
 865                         spa->spa_ddt[c] = NULL;
 866                 }
 867         }
 868 }
 869
 870 boolean_t
 871 ddt_class_contains(spa_t *spa, enum ddt_class max_class, const blkptr_t *bp)
 872 {
 873         ddt_t *ddt;
 874         ddt_entry_t *dde;
 875
 876         if (!BP_GET_DEDUP(bp))
 877                 return (B_FALSE);
 878
 879         if (max_class == DDT_CLASS_UNIQUE)
 880                 return (B_TRUE);
 881
 882         ddt = spa->spa_ddt[BP_GET_CHECKSUM(bp)];
 883         dde = kmem_cache_alloc(ddt_entry_cache, KM_SLEEP);
 884
 885         ddt_key_fill(&(dde->dde_key), bp);
 886
 887         for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
 888                 for (enum ddt_class class = 0; class <= max_class; class++) {
 889                         if (ddt_object_lookup(ddt, type, class, dde) == 0) {
 890                                 kmem_cache_free(ddt_entry_cache, dde);
 891                                 return (B_TRUE);
 892                         }
 893                 }
 894         }
 895
 896         kmem_cache_free(ddt_entry_cache, dde);
 897         return (B_FALSE);
 898 }
 899
 900 ddt_entry_t *
 901 ddt_repair_start(ddt_t *ddt, const blkptr_t *bp)
 902 {
 903         ddt_key_t ddk;
 904         ddt_entry_t *dde;
 905
 906         ddt_key_fill(&ddk, bp);
 907
 908         dde = ddt_alloc(&ddk);
 909
 910         for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
 911                 for (enum ddt_class class = 0; class < DDT_CLASSES; class++) {
 912                         /*
 913                          * We can only do repair if there are multiple copies
 914                          * of the block.  For anything in the UNIQUE class,
 915                          * there's definitely only one copy, so don't even try.
 916                          */
 917                         if (class != DDT_CLASS_UNIQUE &&
 918                             ddt_object_lookup(ddt, type, class, dde) == 0)
 919                                 return (dde);
 920                 }
 921         }
 922
 923         bzero(dde->dde_phys, sizeof (dde->dde_phys));
 924
 925         return (dde);
 926 }
 927
 928 void
 929 ddt_repair_done(ddt_t *ddt, ddt_entry_t *dde)
 930 {
 931         avl_index_t where;
 932
 933         ddt_enter(ddt);
 934
 935         if (dde->dde_repair_abd != NULL && spa_writeable(ddt->ddt_spa) &&
 936             avl_find(&ddt->ddt_repair_tree, dde, &where) == NULL)
 937                 avl_insert(&ddt->ddt_repair_tree, dde, where);
 938         else
 939                 ddt_free(dde);
 940
 941         ddt_exit(ddt);
 942 }
 943
 944 static void
 945 ddt_repair_entry_done(zio_t *zio)
 946 {
 947         ddt_entry_t *rdde = zio->io_private;
 948
 949         ddt_free(rdde);
 950 }
 951
 952 static void
 953 ddt_repair_entry(ddt_t *ddt, ddt_entry_t *dde, ddt_entry_t *rdde, zio_t *rio)
 954 {
 955         ddt_phys_t *ddp = dde->dde_phys;
 956         ddt_phys_t *rddp = rdde->dde_phys;
 957         ddt_key_t *ddk = &dde->dde_key;
 958         ddt_key_t *rddk = &rdde->dde_key;
 959         zio_t *zio;
 960         blkptr_t blk;
 961
 962         zio = zio_null(rio, rio->io_spa, NULL,
 963             ddt_repair_entry_done, rdde, rio->io_flags);
 964
 965         for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++, rddp++) {
 966                 if (ddp->ddp_phys_birth == 0 ||
 967                     ddp->ddp_phys_birth != rddp->ddp_phys_birth ||
 968                     bcmp(ddp->ddp_dva, rddp->ddp_dva, sizeof (ddp->ddp_dva)))
 969                         continue;
 970                 ddt_bp_create(ddt->ddt_checksum, ddk, ddp, &blk);
 971                 zio_nowait(zio_rewrite(zio, zio->io_spa, 0, &blk,
 972                     rdde->dde_repair_abd, DDK_GET_PSIZE(rddk), NULL, NULL,
 973                     ZIO_PRIORITY_SYNC_WRITE, ZIO_DDT_CHILD_FLAGS(zio), NULL));
 974         }
 975
 976         zio_nowait(zio);
 977 }
 978
 979 static void
 980 ddt_repair_table(ddt_t *ddt, zio_t *rio)
 981 {
 982         spa_t *spa = ddt->ddt_spa;
 983         ddt_entry_t *dde, *rdde_next, *rdde;
 984         avl_tree_t *t = &ddt->ddt_repair_tree;
 985         blkptr_t blk;
 986
 987         if (spa_sync_pass(spa) > 1)
 988                 return;
 989
 990         ddt_enter(ddt);
 991         for (rdde = avl_first(t); rdde != NULL; rdde = rdde_next) {
 992                 rdde_next = AVL_NEXT(t, rdde);
 993                 avl_remove(&ddt->ddt_repair_tree, rdde);
 994                 ddt_exit(ddt);
 995                 ddt_bp_create(ddt->ddt_checksum, &rdde->dde_key, NULL, &blk);
 996                 dde = ddt_repair_start(ddt, &blk);
 997                 ddt_repair_entry(ddt, dde, rdde, rio);
 998                 ddt_repair_done(ddt, dde);
 999                 ddt_enter(ddt);
1000         }
1001         ddt_exit(ddt);
1002 }
1003
1004 static void
1005 ddt_sync_entry(ddt_t *ddt, ddt_entry_t *dde, dmu_tx_t *tx, uint64_t txg)
1006 {
1007         dsl_pool_t *dp = ddt->ddt_spa->spa_dsl_pool;
1008         ddt_phys_t *ddp = dde->dde_phys;
1009         ddt_key_t *ddk = &dde->dde_key;
1010         enum ddt_type otype = dde->dde_type;
1011         enum ddt_type ntype = DDT_TYPE_CURRENT;
1012         enum ddt_class oclass = dde->dde_class;
1013         enum ddt_class nclass;
1014         uint64_t total_refcnt = 0;
1015
1016         ASSERT(dde->dde_loaded);
1017         ASSERT(!dde->dde_loading);
1018
1019         for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1020                 ASSERT(dde->dde_lead_zio[p] == NULL);
1021                 if (ddp->ddp_phys_birth == 0) {
1022                         ASSERT(ddp->ddp_refcnt == 0);
1023                         continue;
1024                 }
1025                 if (p == DDT_PHYS_DITTO) {
1026                         /*
1027                          * Note, we no longer create DDT-DITTO blocks, but we
1028                          * don't want to leak any written by older software.
1029                          */
1030                         ddt_phys_free(ddt, ddk, ddp, txg);
1031                         continue;
1032                 }
1033                 if (ddp->ddp_refcnt == 0)
1034                         ddt_phys_free(ddt, ddk, ddp, txg);
1035                 total_refcnt += ddp->ddp_refcnt;
1036         }
1037
1038         /* We do not create new DDT-DITTO blocks. */
1039         ASSERT0(dde->dde_phys[DDT_PHYS_DITTO].ddp_phys_birth);
1040         if (total_refcnt > 1)
1041                 nclass = DDT_CLASS_DUPLICATE;
1042         else
1043                 nclass = DDT_CLASS_UNIQUE;
1044
1045         if (otype != DDT_TYPES &&
1046             (otype != ntype || oclass != nclass || total_refcnt == 0)) {
1047                 VERIFY(ddt_object_remove(ddt, otype, oclass, dde, tx) == 0);
1048                 ASSERT(ddt_object_lookup(ddt, otype, oclass, dde) == ENOENT);
1049         }
1050
1051         if (total_refcnt != 0) {
1052                 dde->dde_type = ntype;
1053                 dde->dde_class = nclass;
1054                 ddt_stat_update(ddt, dde, 0);
1055                 if (!ddt_object_exists(ddt, ntype, nclass))
1056                         ddt_object_create(ddt, ntype, nclass, tx);
1057                 VERIFY(ddt_object_update(ddt, ntype, nclass, dde, tx) == 0);
1058
1059                 /*
1060                  * If the class changes, the order that we scan this bp
1061                  * changes.  If it decreases, we could miss it, so
1062                  * scan it right now.  (This covers both class changing
1063                  * while we are doing ddt_walk(), and when we are
1064                  * traversing.)
1065                  */
1066                 if (nclass < oclass) {
1067                         dsl_scan_ddt_entry(dp->dp_scan,
1068                             ddt->ddt_checksum, dde, tx);
1069                 }
1070         }
1071 }
1072
1073 static void
1074 ddt_sync_table(ddt_t *ddt, dmu_tx_t *tx, uint64_t txg)
1075 {
1076         spa_t *spa = ddt->ddt_spa;
1077         ddt_entry_t *dde;
1078         void *cookie = NULL;
1079
1080         if (avl_numnodes(&ddt->ddt_tree) == 0)
1081                 return;
1082
1083         ASSERT(spa->spa_uberblock.ub_version >= SPA_VERSION_DEDUP);
1084
1085         if (spa->spa_ddt_stat_object == 0) {
1086                 spa->spa_ddt_stat_object = zap_create_link(ddt->ddt_os,
1087                     DMU_OT_DDT_STATS, DMU_POOL_DIRECTORY_OBJECT,
1088                     DMU_POOL_DDT_STATS, tx);
1089         }
1090
1091         while ((dde = avl_destroy_nodes(&ddt->ddt_tree, &cookie)) != NULL) {
1092                 ddt_sync_entry(ddt, dde, tx, txg);
1093                 ddt_free(dde);
1094         }
1095
1096         for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
1097                 uint64_t add, count = 0;
1098                 for (enum ddt_class class = 0; class < DDT_CLASSES; class++) {
1099                         if (ddt_object_exists(ddt, type, class)) {
1100                                 ddt_object_sync(ddt, type, class, tx);
1101                                 VERIFY(ddt_object_count(ddt, type, class,
1102                                     &add) == 0);
1103                                 count += add;
1104                         }
1105                 }
1106                 for (enum ddt_class class = 0; class < DDT_CLASSES; class++) {
1107                         if (count == 0 && ddt_object_exists(ddt, type, class))
1108                                 ddt_object_destroy(ddt, type, class, tx);
1109                 }
1110         }
1111
1112         bcopy(ddt->ddt_histogram, &ddt->ddt_histogram_cache,
1113             sizeof (ddt->ddt_histogram));
1114         spa->spa_dedup_dspace = ~0ULL;
1115 }
1116
1117 void
1118 ddt_sync(spa_t *spa, uint64_t txg)
1119 {
1120         dsl_scan_t *scn = spa->spa_dsl_pool->dp_scan;
1121         dmu_tx_t *tx;
1122         zio_t *rio;
1123
1124         ASSERT(spa_syncing_txg(spa) == txg);
1125
1126         tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
1127
1128         rio = zio_root(spa, NULL, NULL,
1129             ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SELF_HEAL);
1130
1131         /*
1132          * This function may cause an immediate scan of ddt blocks (see
1133          * the comment above dsl_scan_ddt() for details). We set the
1134          * scan's root zio here so that we can wait for any scan IOs in
1135          * addition to the regular ddt IOs.
1136          */
1137         ASSERT3P(scn->scn_zio_root, ==, NULL);
1138         scn->scn_zio_root = rio;
1139
1140         for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
1141                 ddt_t *ddt = spa->spa_ddt[c];
1142                 if (ddt == NULL)
1143                         continue;
1144                 ddt_sync_table(ddt, tx, txg);
1145                 ddt_repair_table(ddt, rio);
1146         }
1147
1148         (void) zio_wait(rio);
1149         scn->scn_zio_root = NULL;
1150
1151         dmu_tx_commit(tx);
1152 }
1153
1154 int
1155 ddt_walk(spa_t *spa, ddt_bookmark_t *ddb, ddt_entry_t *dde)
1156 {
1157         do {
1158                 do {
1159                         do {
1160                                 ddt_t *ddt = spa->spa_ddt[ddb->ddb_checksum];
1161                                 int error = ENOENT;
1162                                 if (ddt_object_exists(ddt, ddb->ddb_type,
1163                                     ddb->ddb_class)) {
1164                                         error = ddt_object_walk(ddt,
1165                                             ddb->ddb_type, ddb->ddb_class,
1166                                             &ddb->ddb_cursor, dde);
1167                                 }
1168                                 dde->dde_type = ddb->ddb_type;
1169                                 dde->dde_class = ddb->ddb_class;
1170                                 if (error == 0)
1171                                         return (0);
1172                                 if (error != ENOENT)
1173                                         return (error);
1174                                 ddb->ddb_cursor = 0;
1175                         } while (++ddb->ddb_checksum < ZIO_CHECKSUM_FUNCTIONS);
1176                         ddb->ddb_checksum = 0;
1177                 } while (++ddb->ddb_type < DDT_TYPES);
1178                 ddb->ddb_type = 0;
1179         } while (++ddb->ddb_class < DDT_CLASSES);
1180
1181         return (SET_ERROR(ENOENT));
1182 }
1183
1184 /* BEGIN CSTYLED */
1185 ZFS_MODULE_PARAM(zfs_dedup, zfs_dedup_, prefetch, INT, ZMOD_RW,
1186         "Enable prefetching dedup-ed blks");
1187 /* END CSTYLED */