drivers/md/persistent-data/dm-space-map-common.c

   1 /*
   2  * Copyright (C) 2011 Red Hat, Inc.
   3  *
   4  * This file is released under the GPL.
   5  */
   6
   7 #include "dm-space-map-common.h"
   8 #include "dm-transaction-manager.h"
   9
  10 #include <linux/bitops.h>
  11 #include <linux/device-mapper.h>
  12
  13 #define DM_MSG_PREFIX "space map common"
  14
  15 /*----------------------------------------------------------------*/
  16
  17 /*
  18  * Index validator.
  19  */
  20 #define INDEX_CSUM_XOR 160478
  21
  22 static void index_prepare_for_write(struct dm_block_validator *v,
  23                                     struct dm_block *b,
  24                                     size_t block_size)
  25 {
  26         struct disk_metadata_index *mi_le = dm_block_data(b);
  27
  28         mi_le->blocknr = cpu_to_le64(dm_block_location(b));
  29         mi_le->csum = cpu_to_le32(dm_bm_checksum(&mi_le->padding,
  30                                                  block_size - sizeof(__le32),
  31                                                  INDEX_CSUM_XOR));
  32 }
  33
  34 static int index_check(struct dm_block_validator *v,
  35                        struct dm_block *b,
  36                        size_t block_size)
  37 {
  38         struct disk_metadata_index *mi_le = dm_block_data(b);
  39         __le32 csum_disk;
  40
  41         if (dm_block_location(b) != le64_to_cpu(mi_le->blocknr)) {
  42                 DMERR_LIMIT("index_check failed: blocknr %llu != wanted %llu",
  43                             le64_to_cpu(mi_le->blocknr), dm_block_location(b));
  44                 return -ENOTBLK;
  45         }
  46
  47         csum_disk = cpu_to_le32(dm_bm_checksum(&mi_le->padding,
  48                                                block_size - sizeof(__le32),
  49                                                INDEX_CSUM_XOR));
  50         if (csum_disk != mi_le->csum) {
  51                 DMERR_LIMIT("index_check failed: csum %u != wanted %u",
  52                             le32_to_cpu(csum_disk), le32_to_cpu(mi_le->csum));
  53                 return -EILSEQ;
  54         }
  55
  56         return 0;
  57 }
  58
  59 static struct dm_block_validator index_validator = {
  60         .name = "index",
  61         .prepare_for_write = index_prepare_for_write,
  62         .check = index_check
  63 };
  64
  65 /*----------------------------------------------------------------*/
  66
  67 /*
  68  * Bitmap validator
  69  */
  70 #define BITMAP_CSUM_XOR 240779
  71
  72 static void bitmap_prepare_for_write(struct dm_block_validator *v,
  73                                      struct dm_block *b,
  74                                      size_t block_size)
  75 {
  76         struct disk_bitmap_header *disk_header = dm_block_data(b);
  77
  78         disk_header->blocknr = cpu_to_le64(dm_block_location(b));
  79         disk_header->csum = cpu_to_le32(dm_bm_checksum(&disk_header->not_used,
  80                                                        block_size - sizeof(__le32),
  81                                                        BITMAP_CSUM_XOR));
  82 }
  83
  84 static int bitmap_check(struct dm_block_validator *v,
  85                         struct dm_block *b,
  86                         size_t block_size)
  87 {
  88         struct disk_bitmap_header *disk_header = dm_block_data(b);
  89         __le32 csum_disk;
  90
  91         if (dm_block_location(b) != le64_to_cpu(disk_header->blocknr)) {
  92                 DMERR_LIMIT("bitmap check failed: blocknr %llu != wanted %llu",
  93                             le64_to_cpu(disk_header->blocknr), dm_block_location(b));
  94                 return -ENOTBLK;
  95         }
  96
  97         csum_disk = cpu_to_le32(dm_bm_checksum(&disk_header->not_used,
  98                                                block_size - sizeof(__le32),
  99                                                BITMAP_CSUM_XOR));
 100         if (csum_disk != disk_header->csum) {
 101                 DMERR_LIMIT("bitmap check failed: csum %u != wanted %u",
 102                             le32_to_cpu(csum_disk), le32_to_cpu(disk_header->csum));
 103                 return -EILSEQ;
 104         }
 105
 106         return 0;
 107 }
 108
 109 static struct dm_block_validator dm_sm_bitmap_validator = {
 110         .name = "sm_bitmap",
 111         .prepare_for_write = bitmap_prepare_for_write,
 112         .check = bitmap_check
 113 };
 114
 115 /*----------------------------------------------------------------*/
 116
 117 #define ENTRIES_PER_WORD 32
 118 #define ENTRIES_SHIFT   5
 119
 120 static void *dm_bitmap_data(struct dm_block *b)
 121 {
 122         return dm_block_data(b) + sizeof(struct disk_bitmap_header);
 123 }
 124
 125 #define WORD_MASK_HIGH 0xAAAAAAAAAAAAAAAAULL
 126
 127 static unsigned bitmap_word_used(void *addr, unsigned b)
 128 {
 129         __le64 *words_le = addr;
 130         __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
 131
 132         uint64_t bits = le64_to_cpu(*w_le);
 133         uint64_t mask = (bits + WORD_MASK_HIGH + 1) & WORD_MASK_HIGH;
 134
 135         return !(~bits & mask);
 136 }
 137
 138 static unsigned sm_lookup_bitmap(void *addr, unsigned b)
 139 {
 140         __le64 *words_le = addr;
 141         __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
 142         unsigned hi, lo;
 143
 144         b = (b & (ENTRIES_PER_WORD - 1)) << 1;
 145         hi = !!test_bit_le(b, (void *) w_le);
 146         lo = !!test_bit_le(b + 1, (void *) w_le);
 147         return (hi << 1) | lo;
 148 }
 149
 150 static void sm_set_bitmap(void *addr, unsigned b, unsigned val)
 151 {
 152         __le64 *words_le = addr;
 153         __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
 154
 155         b = (b & (ENTRIES_PER_WORD - 1)) << 1;
 156
 157         if (val & 2)
 158                 __set_bit_le(b, (void *) w_le);
 159         else
 160                 __clear_bit_le(b, (void *) w_le);
 161
 162         if (val & 1)
 163                 __set_bit_le(b + 1, (void *) w_le);
 164         else
 165                 __clear_bit_le(b + 1, (void *) w_le);
 166 }
 167
 168 static int sm_find_free(void *addr, unsigned begin, unsigned end,
 169                         unsigned *result)
 170 {
 171         while (begin < end) {
 172                 if (!(begin & (ENTRIES_PER_WORD - 1)) &&
 173                     bitmap_word_used(addr, begin)) {
 174                         begin += ENTRIES_PER_WORD;
 175                         continue;
 176                 }
 177
 178                 if (!sm_lookup_bitmap(addr, begin)) {
 179                         *result = begin;
 180                         return 0;
 181                 }
 182
 183                 begin++;
 184         }
 185
 186         return -ENOSPC;
 187 }
 188
 189 /*----------------------------------------------------------------*/
 190
 191 static int sm_ll_init(struct ll_disk *ll, struct dm_transaction_manager *tm)
 192 {
 193         ll->tm = tm;
 194
 195         ll->bitmap_info.tm = tm;
 196         ll->bitmap_info.levels = 1;
 197
 198         /*
 199          * Because the new bitmap blocks are created via a shadow
 200          * operation, the old entry has already had its reference count
 201          * decremented and we don't need the btree to do any bookkeeping.
 202          */
 203         ll->bitmap_info.value_type.size = sizeof(struct disk_index_entry);
 204         ll->bitmap_info.value_type.inc = NULL;
 205         ll->bitmap_info.value_type.dec = NULL;
 206         ll->bitmap_info.value_type.equal = NULL;
 207
 208         ll->ref_count_info.tm = tm;
 209         ll->ref_count_info.levels = 1;
 210         ll->ref_count_info.value_type.size = sizeof(uint32_t);
 211         ll->ref_count_info.value_type.inc = NULL;
 212         ll->ref_count_info.value_type.dec = NULL;
 213         ll->ref_count_info.value_type.equal = NULL;
 214
 215         ll->block_size = dm_bm_block_size(dm_tm_get_bm(tm));
 216
 217         if (ll->block_size > (1 << 30)) {
 218                 DMERR("block size too big to hold bitmaps");
 219                 return -EINVAL;
 220         }
 221
 222         ll->entries_per_block = (ll->block_size - sizeof(struct disk_bitmap_header)) *
 223                 ENTRIES_PER_BYTE;
 224         ll->nr_blocks = 0;
 225         ll->bitmap_root = 0;
 226         ll->ref_count_root = 0;
 227         ll->bitmap_index_changed = false;
 228
 229         return 0;
 230 }
 231
 232 int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
 233 {
 234         int r;
 235         dm_block_t i, nr_blocks, nr_indexes;
 236         unsigned old_blocks, blocks;
 237
 238         nr_blocks = ll->nr_blocks + extra_blocks;
 239         old_blocks = dm_sector_div_up(ll->nr_blocks, ll->entries_per_block);
 240         blocks = dm_sector_div_up(nr_blocks, ll->entries_per_block);
 241
 242         nr_indexes = dm_sector_div_up(nr_blocks, ll->entries_per_block);
 243         if (nr_indexes > ll->max_entries(ll)) {
 244                 DMERR("space map too large");
 245                 return -EINVAL;
 246         }
 247
 248         for (i = old_blocks; i < blocks; i++) {
 249                 struct dm_block *b;
 250                 struct disk_index_entry idx;
 251
 252                 r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b);
 253                 if (r < 0)
 254                         return r;
 255                 idx.blocknr = cpu_to_le64(dm_block_location(b));
 256
 257                 r = dm_tm_unlock(ll->tm, b);
 258                 if (r < 0)
 259                         return r;
 260
 261                 idx.nr_free = cpu_to_le32(ll->entries_per_block);
 262                 idx.none_free_before = 0;
 263
 264                 r = ll->save_ie(ll, i, &idx);
 265                 if (r < 0)
 266                         return r;
 267         }
 268
 269         ll->nr_blocks = nr_blocks;
 270         return 0;
 271 }
 272
 273 int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result)
 274 {
 275         int r;
 276         dm_block_t index = b;
 277         struct disk_index_entry ie_disk;
 278         struct dm_block *blk;
 279
 280         b = do_div(index, ll->entries_per_block);
 281         r = ll->load_ie(ll, index, &ie_disk);
 282         if (r < 0)
 283                 return r;
 284
 285         r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr),
 286                             &dm_sm_bitmap_validator, &blk);
 287         if (r < 0)
 288                 return r;
 289
 290         *result = sm_lookup_bitmap(dm_bitmap_data(blk), b);
 291
 292         return dm_tm_unlock(ll->tm, blk);
 293 }
 294
 295 static int sm_ll_lookup_big_ref_count(struct ll_disk *ll, dm_block_t b,
 296                                       uint32_t *result)
 297 {
 298         __le32 le_rc;
 299         int r;
 300
 301         r = dm_btree_lookup(&ll->ref_count_info, ll->ref_count_root, &b, &le_rc);
 302         if (r < 0)
 303                 return r;
 304
 305         *result = le32_to_cpu(le_rc);
 306
 307         return r;
 308 }
 309
 310 int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result)
 311 {
 312         int r = sm_ll_lookup_bitmap(ll, b, result);
 313
 314         if (r)
 315                 return r;
 316
 317         if (*result != 3)
 318                 return r;
 319
 320         return sm_ll_lookup_big_ref_count(ll, b, result);
 321 }
 322
 323 int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
 324                           dm_block_t end, dm_block_t *result)
 325 {
 326         int r;
 327         struct disk_index_entry ie_disk;
 328         dm_block_t i, index_begin = begin;
 329         dm_block_t index_end = dm_sector_div_up(end, ll->entries_per_block);
 330
 331         /*
 332          * FIXME: Use shifts
 333          */
 334         begin = do_div(index_begin, ll->entries_per_block);
 335         end = do_div(end, ll->entries_per_block);
 336
 337         for (i = index_begin; i < index_end; i++, begin = 0) {
 338                 struct dm_block *blk;
 339                 unsigned position;
 340                 uint32_t bit_end;
 341
 342                 r = ll->load_ie(ll, i, &ie_disk);
 343                 if (r < 0)
 344                         return r;
 345
 346                 if (le32_to_cpu(ie_disk.nr_free) == 0)
 347                         continue;
 348
 349                 r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr),
 350                                     &dm_sm_bitmap_validator, &blk);
 351                 if (r < 0)
 352                         return r;
 353
 354                 bit_end = (i == index_end - 1) ?  end : ll->entries_per_block;
 355
 356                 r = sm_find_free(dm_bitmap_data(blk),
 357                                  max_t(unsigned, begin, le32_to_cpu(ie_disk.none_free_before)),
 358                                  bit_end, &position);
 359                 if (r == -ENOSPC) {
 360                         /*
 361                          * This might happen because we started searching
 362                          * part way through the bitmap.
 363                          */
 364                         dm_tm_unlock(ll->tm, blk);
 365                         continue;
 366
 367                 } else if (r < 0) {
 368                         dm_tm_unlock(ll->tm, blk);
 369                         return r;
 370                 }
 371
 372                 r = dm_tm_unlock(ll->tm, blk);
 373                 if (r < 0)
 374                         return r;
 375
 376                 *result = i * ll->entries_per_block + (dm_block_t) position;
 377                 return 0;
 378         }
 379
 380         return -ENOSPC;
 381 }
 382
 383 static int sm_ll_mutate(struct ll_disk *ll, dm_block_t b,
 384                         uint32_t (*mutator)(void *context, uint32_t old),
 385                         void *context, enum allocation_event *ev)
 386 {
 387         int r;
 388         uint32_t bit, old, ref_count;
 389         struct dm_block *nb;
 390         dm_block_t index = b;
 391         struct disk_index_entry ie_disk;
 392         void *bm_le;
 393         int inc;
 394
 395         bit = do_div(index, ll->entries_per_block);
 396         r = ll->load_ie(ll, index, &ie_disk);
 397         if (r < 0)
 398                 return r;
 399
 400         r = dm_tm_shadow_block(ll->tm, le64_to_cpu(ie_disk.blocknr),
 401                                &dm_sm_bitmap_validator, &nb, &inc);
 402         if (r < 0) {
 403                 DMERR("dm_tm_shadow_block() failed");
 404                 return r;
 405         }
 406         ie_disk.blocknr = cpu_to_le64(dm_block_location(nb));
 407
 408         bm_le = dm_bitmap_data(nb);
 409         old = sm_lookup_bitmap(bm_le, bit);
 410
 411         if (old > 2) {
 412                 r = sm_ll_lookup_big_ref_count(ll, b, &old);
 413                 if (r < 0)
 414                         return r;
 415         }
 416
 417         ref_count = mutator(context, old);
 418
 419         if (ref_count <= 2) {
 420                 sm_set_bitmap(bm_le, bit, ref_count);
 421
 422                 r = dm_tm_unlock(ll->tm, nb);
 423                 if (r < 0)
 424                         return r;
 425
 426                 if (old > 2) {
 427                         r = dm_btree_remove(&ll->ref_count_info,
 428                                             ll->ref_count_root,
 429                                             &b, &ll->ref_count_root);
 430                         if (r)
 431                                 return r;
 432                 }
 433
 434         } else {
 435                 __le32 le_rc = cpu_to_le32(ref_count);
 436
 437                 sm_set_bitmap(bm_le, bit, 3);
 438                 r = dm_tm_unlock(ll->tm, nb);
 439                 if (r < 0)
 440                         return r;
 441
 442                 __dm_bless_for_disk(&le_rc);
 443                 r = dm_btree_insert(&ll->ref_count_info, ll->ref_count_root,
 444                                     &b, &le_rc, &ll->ref_count_root);
 445                 if (r < 0) {
 446                         DMERR("ref count insert failed");
 447                         return r;
 448                 }
 449         }
 450
 451         if (ref_count && !old) {
 452                 *ev = SM_ALLOC;
 453                 ll->nr_allocated++;
 454                 le32_add_cpu(&ie_disk.nr_free, -1);
 455                 if (le32_to_cpu(ie_disk.none_free_before) == bit)
 456                         ie_disk.none_free_before = cpu_to_le32(bit + 1);
 457
 458         } else if (old && !ref_count) {
 459                 *ev = SM_FREE;
 460                 ll->nr_allocated--;
 461                 le32_add_cpu(&ie_disk.nr_free, 1);
 462                 ie_disk.none_free_before = cpu_to_le32(min(le32_to_cpu(ie_disk.none_free_before), bit));
 463         }
 464
 465         return ll->save_ie(ll, index, &ie_disk);
 466 }
 467
 468 static uint32_t set_ref_count(void *context, uint32_t old)
 469 {
 470         return *((uint32_t *) context);
 471 }
 472
 473 int sm_ll_insert(struct ll_disk *ll, dm_block_t b,
 474                  uint32_t ref_count, enum allocation_event *ev)
 475 {
 476         return sm_ll_mutate(ll, b, set_ref_count, &ref_count, ev);
 477 }
 478
 479 static uint32_t inc_ref_count(void *context, uint32_t old)
 480 {
 481         return old + 1;
 482 }
 483
 484 int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev)
 485 {
 486         return sm_ll_mutate(ll, b, inc_ref_count, NULL, ev);
 487 }
 488
 489 static uint32_t dec_ref_count(void *context, uint32_t old)
 490 {
 491         return old - 1;
 492 }
 493
 494 int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev)
 495 {
 496         return sm_ll_mutate(ll, b, dec_ref_count, NULL, ev);
 497 }
 498
 499 int sm_ll_commit(struct ll_disk *ll)
 500 {
 501         int r = 0;
 502
 503         if (ll->bitmap_index_changed) {
 504                 r = ll->commit(ll);
 505                 if (!r)
 506                         ll->bitmap_index_changed = false;
 507         }
 508
 509         return r;
 510 }
 511
 512 /*----------------------------------------------------------------*/
 513
 514 static int metadata_ll_load_ie(struct ll_disk *ll, dm_block_t index,
 515                                struct disk_index_entry *ie)
 516 {
 517         memcpy(ie, ll->mi_le.index + index, sizeof(*ie));
 518         return 0;
 519 }
 520
 521 static int metadata_ll_save_ie(struct ll_disk *ll, dm_block_t index,
 522                                struct disk_index_entry *ie)
 523 {
 524         ll->bitmap_index_changed = true;
 525         memcpy(ll->mi_le.index + index, ie, sizeof(*ie));
 526         return 0;
 527 }
 528
 529 static int metadata_ll_init_index(struct ll_disk *ll)
 530 {
 531         int r;
 532         struct dm_block *b;
 533
 534         r = dm_tm_new_block(ll->tm, &index_validator, &b);
 535         if (r < 0)
 536                 return r;
 537
 538         memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le));
 539         ll->bitmap_root = dm_block_location(b);
 540
 541         return dm_tm_unlock(ll->tm, b);
 542 }
 543
 544 static int metadata_ll_open(struct ll_disk *ll)
 545 {
 546         int r;
 547         struct dm_block *block;
 548
 549         r = dm_tm_read_lock(ll->tm, ll->bitmap_root,
 550                             &index_validator, &block);
 551         if (r)
 552                 return r;
 553
 554         memcpy(&ll->mi_le, dm_block_data(block), sizeof(ll->mi_le));
 555         return dm_tm_unlock(ll->tm, block);
 556 }
 557
 558 static dm_block_t metadata_ll_max_entries(struct ll_disk *ll)
 559 {
 560         return MAX_METADATA_BITMAPS;
 561 }
 562
 563 static int metadata_ll_commit(struct ll_disk *ll)
 564 {
 565         int r, inc;
 566         struct dm_block *b;
 567
 568         r = dm_tm_shadow_block(ll->tm, ll->bitmap_root, &index_validator, &b, &inc);
 569         if (r)
 570                 return r;
 571
 572         memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le));
 573         ll->bitmap_root = dm_block_location(b);
 574
 575         return dm_tm_unlock(ll->tm, b);
 576 }
 577
 578 int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm)
 579 {
 580         int r;
 581
 582         r = sm_ll_init(ll, tm);
 583         if (r < 0)
 584                 return r;
 585
 586         ll->load_ie = metadata_ll_load_ie;
 587         ll->save_ie = metadata_ll_save_ie;
 588         ll->init_index = metadata_ll_init_index;
 589         ll->open_index = metadata_ll_open;
 590         ll->max_entries = metadata_ll_max_entries;
 591         ll->commit = metadata_ll_commit;
 592
 593         ll->nr_blocks = 0;
 594         ll->nr_allocated = 0;
 595
 596         r = ll->init_index(ll);
 597         if (r < 0)
 598                 return r;
 599
 600         r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root);
 601         if (r < 0)
 602                 return r;
 603
 604         return 0;
 605 }
 606
 607 int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
 608                         void *root_le, size_t len)
 609 {
 610         int r;
 611         struct disk_sm_root *smr = root_le;
 612
 613         if (len < sizeof(struct disk_sm_root)) {
 614                 DMERR("sm_metadata root too small");
 615                 return -ENOMEM;
 616         }
 617
 618         r = sm_ll_init(ll, tm);
 619         if (r < 0)
 620                 return r;
 621
 622         ll->load_ie = metadata_ll_load_ie;
 623         ll->save_ie = metadata_ll_save_ie;
 624         ll->init_index = metadata_ll_init_index;
 625         ll->open_index = metadata_ll_open;
 626         ll->max_entries = metadata_ll_max_entries;
 627         ll->commit = metadata_ll_commit;
 628
 629         ll->nr_blocks = le64_to_cpu(smr->nr_blocks);
 630         ll->nr_allocated = le64_to_cpu(smr->nr_allocated);
 631         ll->bitmap_root = le64_to_cpu(smr->bitmap_root);
 632         ll->ref_count_root = le64_to_cpu(smr->ref_count_root);
 633
 634         return ll->open_index(ll);
 635 }
 636
 637 /*----------------------------------------------------------------*/
 638
 639 static int disk_ll_load_ie(struct ll_disk *ll, dm_block_t index,
 640                            struct disk_index_entry *ie)
 641 {
 642         return dm_btree_lookup(&ll->bitmap_info, ll->bitmap_root, &index, ie);
 643 }
 644
 645 static int disk_ll_save_ie(struct ll_disk *ll, dm_block_t index,
 646                            struct disk_index_entry *ie)
 647 {
 648         __dm_bless_for_disk(ie);
 649         return dm_btree_insert(&ll->bitmap_info, ll->bitmap_root,
 650                                &index, ie, &ll->bitmap_root);
 651 }
 652
 653 static int disk_ll_init_index(struct ll_disk *ll)
 654 {
 655         return dm_btree_empty(&ll->bitmap_info, &ll->bitmap_root);
 656 }
 657
 658 static int disk_ll_open(struct ll_disk *ll)
 659 {
 660         /* nothing to do */
 661         return 0;
 662 }
 663
 664 static dm_block_t disk_ll_max_entries(struct ll_disk *ll)
 665 {
 666         return -1ULL;
 667 }
 668
 669 static int disk_ll_commit(struct ll_disk *ll)
 670 {
 671         return 0;
 672 }
 673
 674 int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm)
 675 {
 676         int r;
 677
 678         r = sm_ll_init(ll, tm);
 679         if (r < 0)
 680                 return r;
 681
 682         ll->load_ie = disk_ll_load_ie;
 683         ll->save_ie = disk_ll_save_ie;
 684         ll->init_index = disk_ll_init_index;
 685         ll->open_index = disk_ll_open;
 686         ll->max_entries = disk_ll_max_entries;
 687         ll->commit = disk_ll_commit;
 688
 689         ll->nr_blocks = 0;
 690         ll->nr_allocated = 0;
 691
 692         r = ll->init_index(ll);
 693         if (r < 0)
 694                 return r;
 695
 696         r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root);
 697         if (r < 0)
 698                 return r;
 699
 700         return 0;
 701 }
 702
 703 int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
 704                     void *root_le, size_t len)
 705 {
 706         int r;
 707         struct disk_sm_root *smr = root_le;
 708
 709         if (len < sizeof(struct disk_sm_root)) {
 710                 DMERR("sm_metadata root too small");
 711                 return -ENOMEM;
 712         }
 713
 714         r = sm_ll_init(ll, tm);
 715         if (r < 0)
 716                 return r;
 717
 718         ll->load_ie = disk_ll_load_ie;
 719         ll->save_ie = disk_ll_save_ie;
 720         ll->init_index = disk_ll_init_index;
 721         ll->open_index = disk_ll_open;
 722         ll->max_entries = disk_ll_max_entries;
 723         ll->commit = disk_ll_commit;
 724
 725         ll->nr_blocks = le64_to_cpu(smr->nr_blocks);
 726         ll->nr_allocated = le64_to_cpu(smr->nr_allocated);
 727         ll->bitmap_root = le64_to_cpu(smr->bitmap_root);
 728         ll->ref_count_root = le64_to_cpu(smr->ref_count_root);
 729
 730         return ll->open_index(ll);
 731 }
 732
 733 /*----------------------------------------------------------------*/