drivers/md/persistent-data/dm-space-map-metadata.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.h"
   8 #include "dm-space-map-common.h"
   9 #include "dm-space-map-metadata.h"
  10
  11 #include <linux/list.h>
  12 #include <linux/slab.h>
  13 #include <linux/device-mapper.h>
  14
  15 #define DM_MSG_PREFIX "space map metadata"
  16
  17 /*----------------------------------------------------------------*/
  18
  19 /*
  20  * An edge triggered threshold.
  21  */
  22 struct threshold {
  23         bool threshold_set;
  24         bool value_set;
  25         dm_block_t threshold;
  26         dm_block_t current_value;
  27         dm_sm_threshold_fn fn;
  28         void *context;
  29 };
  30
  31 static void threshold_init(struct threshold *t)
  32 {
  33         t->threshold_set = false;
  34         t->value_set = false;
  35 }
  36
  37 static void set_threshold(struct threshold *t, dm_block_t value,
  38                           dm_sm_threshold_fn fn, void *context)
  39 {
  40         t->threshold_set = true;
  41         t->threshold = value;
  42         t->fn = fn;
  43         t->context = context;
  44 }
  45
  46 static bool below_threshold(struct threshold *t, dm_block_t value)
  47 {
  48         return t->threshold_set && value <= t->threshold;
  49 }
  50
  51 static bool threshold_already_triggered(struct threshold *t)
  52 {
  53         return t->value_set && below_threshold(t, t->current_value);
  54 }
  55
  56 static void check_threshold(struct threshold *t, dm_block_t value)
  57 {
  58         if (below_threshold(t, value) &&
  59             !threshold_already_triggered(t))
  60                 t->fn(t->context);
  61
  62         t->value_set = true;
  63         t->current_value = value;
  64 }
  65
  66 /*----------------------------------------------------------------*/
  67
  68 /*
  69  * Space map interface.
  70  *
  71  * The low level disk format is written using the standard btree and
  72  * transaction manager.  This means that performing disk operations may
  73  * cause us to recurse into the space map in order to allocate new blocks.
  74  * For this reason we have a pool of pre-allocated blocks large enough to
  75  * service any metadata_ll_disk operation.
  76  */
  77
  78 /*
  79  * FIXME: we should calculate this based on the size of the device.
  80  * Only the metadata space map needs this functionality.
  81  */
  82 #define MAX_RECURSIVE_ALLOCATIONS 1024
  83
  84 enum block_op_type {
  85         BOP_INC,
  86         BOP_DEC
  87 };
  88
  89 struct block_op {
  90         enum block_op_type type;
  91         dm_block_t block;
  92 };
  93
  94 struct bop_ring_buffer {
  95         unsigned begin;
  96         unsigned end;
  97         struct block_op bops[MAX_RECURSIVE_ALLOCATIONS + 1];
  98 };
  99
 100 static void brb_init(struct bop_ring_buffer *brb)
 101 {
 102         brb->begin = 0;
 103         brb->end = 0;
 104 }
 105
 106 static bool brb_empty(struct bop_ring_buffer *brb)
 107 {
 108         return brb->begin == brb->end;
 109 }
 110
 111 static unsigned brb_next(struct bop_ring_buffer *brb, unsigned old)
 112 {
 113         unsigned r = old + 1;
 114         return (r >= (sizeof(brb->bops) / sizeof(*brb->bops))) ? 0 : r;
 115 }
 116
 117 static int brb_push(struct bop_ring_buffer *brb,
 118                     enum block_op_type type, dm_block_t b)
 119 {
 120         struct block_op *bop;
 121         unsigned next = brb_next(brb, brb->end);
 122
 123         /*
 124          * We don't allow the last bop to be filled, this way we can
 125          * differentiate between full and empty.
 126          */
 127         if (next == brb->begin)
 128                 return -ENOMEM;
 129
 130         bop = brb->bops + brb->end;
 131         bop->type = type;
 132         bop->block = b;
 133
 134         brb->end = next;
 135
 136         return 0;
 137 }
 138
 139 static int brb_pop(struct bop_ring_buffer *brb, struct block_op *result)
 140 {
 141         struct block_op *bop;
 142
 143         if (brb_empty(brb))
 144                 return -ENODATA;
 145
 146         bop = brb->bops + brb->begin;
 147         result->type = bop->type;
 148         result->block = bop->block;
 149
 150         brb->begin = brb_next(brb, brb->begin);
 151
 152         return 0;
 153 }
 154
 155 /*----------------------------------------------------------------*/
 156
 157 struct sm_metadata {
 158         struct dm_space_map sm;
 159
 160         struct ll_disk ll;
 161         struct ll_disk old_ll;
 162
 163         dm_block_t begin;
 164
 165         unsigned recursion_count;
 166         unsigned allocated_this_transaction;
 167         struct bop_ring_buffer uncommitted;
 168
 169         struct threshold threshold;
 170 };
 171
 172 static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
 173 {
 174         int r = brb_push(&smm->uncommitted, type, b);
 175
 176         if (r) {
 177                 DMERR("too many recursive allocations");
 178                 return -ENOMEM;
 179         }
 180
 181         return 0;
 182 }
 183
 184 static int commit_bop(struct sm_metadata *smm, struct block_op *op)
 185 {
 186         int r = 0;
 187         enum allocation_event ev;
 188
 189         switch (op->type) {
 190         case BOP_INC:
 191                 r = sm_ll_inc(&smm->ll, op->block, &ev);
 192                 break;
 193
 194         case BOP_DEC:
 195                 r = sm_ll_dec(&smm->ll, op->block, &ev);
 196                 break;
 197         }
 198
 199         return r;
 200 }
 201
 202 static void in(struct sm_metadata *smm)
 203 {
 204         smm->recursion_count++;
 205 }
 206
 207 static int apply_bops(struct sm_metadata *smm)
 208 {
 209         int r = 0;
 210
 211         while (!brb_empty(&smm->uncommitted)) {
 212                 struct block_op bop;
 213
 214                 r = brb_pop(&smm->uncommitted, &bop);
 215                 if (r) {
 216                         DMERR("bug in bop ring buffer");
 217                         break;
 218                 }
 219
 220                 r = commit_bop(smm, &bop);
 221                 if (r)
 222                         break;
 223         }
 224
 225         return r;
 226 }
 227
 228 static int out(struct sm_metadata *smm)
 229 {
 230         int r = 0;
 231
 232         /*
 233          * If we're not recursing then very bad things are happening.
 234          */
 235         if (!smm->recursion_count) {
 236                 DMERR("lost track of recursion depth");
 237                 return -ENOMEM;
 238         }
 239
 240         if (smm->recursion_count == 1)
 241                 apply_bops(smm);
 242
 243         smm->recursion_count--;
 244
 245         return r;
 246 }
 247
 248 /*
 249  * When using the out() function above, we often want to combine an error
 250  * code for the operation run in the recursive context with that from
 251  * out().
 252  */
 253 static int combine_errors(int r1, int r2)
 254 {
 255         return r1 ? r1 : r2;
 256 }
 257
 258 static int recursing(struct sm_metadata *smm)
 259 {
 260         return smm->recursion_count;
 261 }
 262
 263 static void sm_metadata_destroy(struct dm_space_map *sm)
 264 {
 265         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 266
 267         kfree(smm);
 268 }
 269
 270 static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
 271 {
 272         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 273
 274         *count = smm->ll.nr_blocks;
 275
 276         return 0;
 277 }
 278
 279 static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
 280 {
 281         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 282
 283         *count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
 284                  smm->allocated_this_transaction;
 285
 286         return 0;
 287 }
 288
 289 static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
 290                                  uint32_t *result)
 291 {
 292         int r;
 293         unsigned i;
 294         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 295         unsigned adjustment = 0;
 296
 297         /*
 298          * We may have some uncommitted adjustments to add.  This list
 299          * should always be really short.
 300          */
 301         for (i = smm->uncommitted.begin;
 302              i != smm->uncommitted.end;
 303              i = brb_next(&smm->uncommitted, i)) {
 304                 struct block_op *op = smm->uncommitted.bops + i;
 305
 306                 if (op->block != b)
 307                         continue;
 308
 309                 switch (op->type) {
 310                 case BOP_INC:
 311                         adjustment++;
 312                         break;
 313
 314                 case BOP_DEC:
 315                         adjustment--;
 316                         break;
 317                 }
 318         }
 319
 320         r = sm_ll_lookup(&smm->ll, b, result);
 321         if (r)
 322                 return r;
 323
 324         *result += adjustment;
 325
 326         return 0;
 327 }
 328
 329 static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
 330                                               dm_block_t b, int *result)
 331 {
 332         int r, adjustment = 0;
 333         unsigned i;
 334         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 335         uint32_t rc;
 336
 337         /*
 338          * We may have some uncommitted adjustments to add.  This list
 339          * should always be really short.
 340          */
 341         for (i = smm->uncommitted.begin;
 342              i != smm->uncommitted.end;
 343              i = brb_next(&smm->uncommitted, i)) {
 344
 345                 struct block_op *op = smm->uncommitted.bops + i;
 346
 347                 if (op->block != b)
 348                         continue;
 349
 350                 switch (op->type) {
 351                 case BOP_INC:
 352                         adjustment++;
 353                         break;
 354
 355                 case BOP_DEC:
 356                         adjustment--;
 357                         break;
 358                 }
 359         }
 360
 361         if (adjustment > 1) {
 362                 *result = 1;
 363                 return 0;
 364         }
 365
 366         r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
 367         if (r)
 368                 return r;
 369
 370         if (rc == 3)
 371                 /*
 372                  * We err on the side of caution, and always return true.
 373                  */
 374                 *result = 1;
 375         else
 376                 *result = rc + adjustment > 1;
 377
 378         return 0;
 379 }
 380
 381 static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
 382                                  uint32_t count)
 383 {
 384         int r, r2;
 385         enum allocation_event ev;
 386         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 387
 388         if (smm->recursion_count) {
 389                 DMERR("cannot recurse set_count()");
 390                 return -EINVAL;
 391         }
 392
 393         in(smm);
 394         r = sm_ll_insert(&smm->ll, b, count, &ev);
 395         r2 = out(smm);
 396
 397         return combine_errors(r, r2);
 398 }
 399
 400 static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b)
 401 {
 402         int r, r2 = 0;
 403         enum allocation_event ev;
 404         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 405
 406         if (recursing(smm))
 407                 r = add_bop(smm, BOP_INC, b);
 408         else {
 409                 in(smm);
 410                 r = sm_ll_inc(&smm->ll, b, &ev);
 411                 r2 = out(smm);
 412         }
 413
 414         return combine_errors(r, r2);
 415 }
 416
 417 static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b)
 418 {
 419         int r, r2 = 0;
 420         enum allocation_event ev;
 421         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 422
 423         if (recursing(smm))
 424                 r = add_bop(smm, BOP_DEC, b);
 425         else {
 426                 in(smm);
 427                 r = sm_ll_dec(&smm->ll, b, &ev);
 428                 r2 = out(smm);
 429         }
 430
 431         return combine_errors(r, r2);
 432 }
 433
 434 static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
 435 {
 436         int r, r2 = 0;
 437         enum allocation_event ev;
 438         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 439
 440         r = sm_ll_find_free_block(&smm->old_ll, smm->begin, smm->old_ll.nr_blocks, b);
 441         if (r)
 442                 return r;
 443
 444         smm->begin = *b + 1;
 445
 446         if (recursing(smm))
 447                 r = add_bop(smm, BOP_INC, *b);
 448         else {
 449                 in(smm);
 450                 r = sm_ll_inc(&smm->ll, *b, &ev);
 451                 r2 = out(smm);
 452         }
 453
 454         if (!r)
 455                 smm->allocated_this_transaction++;
 456
 457         return combine_errors(r, r2);
 458 }
 459
 460 static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
 461 {
 462         dm_block_t count;
 463         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 464
 465         int r = sm_metadata_new_block_(sm, b);
 466         if (r) {
 467                 DMERR_LIMIT("unable to allocate new metadata block");
 468                 return r;
 469         }
 470
 471         r = sm_metadata_get_nr_free(sm, &count);
 472         if (r) {
 473                 DMERR_LIMIT("couldn't get free block count");
 474                 return r;
 475         }
 476
 477         check_threshold(&smm->threshold, count);
 478
 479         return r;
 480 }
 481
 482 static int sm_metadata_commit(struct dm_space_map *sm)
 483 {
 484         int r;
 485         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 486
 487         r = sm_ll_commit(&smm->ll);
 488         if (r)
 489                 return r;
 490
 491         memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
 492         smm->begin = 0;
 493         smm->allocated_this_transaction = 0;
 494
 495         return 0;
 496 }
 497
 498 static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
 499                                                    dm_block_t threshold,
 500                                                    dm_sm_threshold_fn fn,
 501                                                    void *context)
 502 {
 503         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 504
 505         set_threshold(&smm->threshold, threshold, fn, context);
 506
 507         return 0;
 508 }
 509
 510 static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
 511 {
 512         *result = sizeof(struct disk_sm_root);
 513
 514         return 0;
 515 }
 516
 517 static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
 518 {
 519         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 520         struct disk_sm_root root_le;
 521
 522         root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
 523         root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
 524         root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
 525         root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
 526
 527         if (max < sizeof(root_le))
 528                 return -ENOSPC;
 529
 530         memcpy(where_le, &root_le, sizeof(root_le));
 531
 532         return 0;
 533 }
 534
 535 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks);
 536
 537 static struct dm_space_map ops = {
 538         .destroy = sm_metadata_destroy,
 539         .extend = sm_metadata_extend,
 540         .get_nr_blocks = sm_metadata_get_nr_blocks,
 541         .get_nr_free = sm_metadata_get_nr_free,
 542         .get_count = sm_metadata_get_count,
 543         .count_is_more_than_one = sm_metadata_count_is_more_than_one,
 544         .set_count = sm_metadata_set_count,
 545         .inc_block = sm_metadata_inc_block,
 546         .dec_block = sm_metadata_dec_block,
 547         .new_block = sm_metadata_new_block,
 548         .commit = sm_metadata_commit,
 549         .root_size = sm_metadata_root_size,
 550         .copy_root = sm_metadata_copy_root,
 551         .register_threshold_callback = sm_metadata_register_threshold_callback
 552 };
 553
 554 /*----------------------------------------------------------------*/
 555
 556 /*
 557  * When a new space map is created that manages its own space.  We use
 558  * this tiny bootstrap allocator.
 559  */
 560 static void sm_bootstrap_destroy(struct dm_space_map *sm)
 561 {
 562 }
 563
 564 static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 565 {
 566         DMERR("bootstrap doesn't support extend");
 567
 568         return -EINVAL;
 569 }
 570
 571 static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
 572 {
 573         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 574
 575         *count = smm->ll.nr_blocks;
 576
 577         return 0;
 578 }
 579
 580 static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
 581 {
 582         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 583
 584         *count = smm->ll.nr_blocks - smm->begin;
 585
 586         return 0;
 587 }
 588
 589 static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
 590                                   uint32_t *result)
 591 {
 592         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 593
 594         *result = (b < smm->begin) ? 1 : 0;
 595
 596         return 0;
 597 }
 598
 599 static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
 600                                                dm_block_t b, int *result)
 601 {
 602         *result = 0;
 603
 604         return 0;
 605 }
 606
 607 static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
 608                                   uint32_t count)
 609 {
 610         DMERR("bootstrap doesn't support set_count");
 611
 612         return -EINVAL;
 613 }
 614
 615 static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
 616 {
 617         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 618
 619         /*
 620          * We know the entire device is unused.
 621          */
 622         if (smm->begin == smm->ll.nr_blocks)
 623                 return -ENOSPC;
 624
 625         *b = smm->begin++;
 626
 627         return 0;
 628 }
 629
 630 static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b)
 631 {
 632         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 633
 634         return add_bop(smm, BOP_INC, b);
 635 }
 636
 637 static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b)
 638 {
 639         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 640
 641         return add_bop(smm, BOP_DEC, b);
 642 }
 643
 644 static int sm_bootstrap_commit(struct dm_space_map *sm)
 645 {
 646         return 0;
 647 }
 648
 649 static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
 650 {
 651         DMERR("bootstrap doesn't support root_size");
 652
 653         return -EINVAL;
 654 }
 655
 656 static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
 657                                   size_t max)
 658 {
 659         DMERR("bootstrap doesn't support copy_root");
 660
 661         return -EINVAL;
 662 }
 663
 664 static struct dm_space_map bootstrap_ops = {
 665         .destroy = sm_bootstrap_destroy,
 666         .extend = sm_bootstrap_extend,
 667         .get_nr_blocks = sm_bootstrap_get_nr_blocks,
 668         .get_nr_free = sm_bootstrap_get_nr_free,
 669         .get_count = sm_bootstrap_get_count,
 670         .count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
 671         .set_count = sm_bootstrap_set_count,
 672         .inc_block = sm_bootstrap_inc_block,
 673         .dec_block = sm_bootstrap_dec_block,
 674         .new_block = sm_bootstrap_new_block,
 675         .commit = sm_bootstrap_commit,
 676         .root_size = sm_bootstrap_root_size,
 677         .copy_root = sm_bootstrap_copy_root,
 678         .register_threshold_callback = NULL
 679 };
 680
 681 /*----------------------------------------------------------------*/
 682
 683 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 684 {
 685         int r, i;
 686         enum allocation_event ev;
 687         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 688         dm_block_t old_len = smm->ll.nr_blocks;
 689
 690         /*
 691          * Flick into a mode where all blocks get allocated in the new area.
 692          */
 693         smm->begin = old_len;
 694         memcpy(sm, &bootstrap_ops, sizeof(*sm));
 695
 696         /*
 697          * Extend.
 698          */
 699         r = sm_ll_extend(&smm->ll, extra_blocks);
 700         if (r)
 701                 goto out;
 702
 703         /*
 704          * We repeatedly increment then commit until the commit doesn't
 705          * allocate any new blocks.
 706          */
 707         do {
 708                 for (i = old_len; !r && i < smm->begin; i++) {
 709                         r = sm_ll_inc(&smm->ll, i, &ev);
 710                         if (r)
 711                                 goto out;
 712                 }
 713                 old_len = smm->begin;
 714
 715                 r = apply_bops(smm);
 716                 if (r) {
 717                         DMERR("%s: apply_bops failed", __func__);
 718                         goto out;
 719                 }
 720
 721                 r = sm_ll_commit(&smm->ll);
 722                 if (r)
 723                         goto out;
 724
 725         } while (old_len != smm->begin);
 726
 727 out:
 728         /*
 729          * Switch back to normal behaviour.
 730          */
 731         memcpy(sm, &ops, sizeof(*sm));
 732         return r;
 733 }
 734
 735 /*----------------------------------------------------------------*/
 736
 737 struct dm_space_map *dm_sm_metadata_init(void)
 738 {
 739         struct sm_metadata *smm;
 740
 741         smm = kmalloc(sizeof(*smm), GFP_KERNEL);
 742         if (!smm)
 743                 return ERR_PTR(-ENOMEM);
 744
 745         memcpy(&smm->sm, &ops, sizeof(smm->sm));
 746
 747         return &smm->sm;
 748 }
 749
 750 int dm_sm_metadata_create(struct dm_space_map *sm,
 751                           struct dm_transaction_manager *tm,
 752                           dm_block_t nr_blocks,
 753                           dm_block_t superblock)
 754 {
 755         int r;
 756         dm_block_t i;
 757         enum allocation_event ev;
 758         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 759
 760         smm->begin = superblock + 1;
 761         smm->recursion_count = 0;
 762         smm->allocated_this_transaction = 0;
 763         brb_init(&smm->uncommitted);
 764         threshold_init(&smm->threshold);
 765
 766         memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
 767
 768         r = sm_ll_new_metadata(&smm->ll, tm);
 769         if (r)
 770                 return r;
 771
 772         if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
 773                 nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
 774         r = sm_ll_extend(&smm->ll, nr_blocks);
 775         if (r)
 776                 return r;
 777
 778         memcpy(&smm->sm, &ops, sizeof(smm->sm));
 779
 780         /*
 781          * Now we need to update the newly created data structures with the
 782          * allocated blocks that they were built from.
 783          */
 784         for (i = superblock; !r && i < smm->begin; i++)
 785                 r = sm_ll_inc(&smm->ll, i, &ev);
 786
 787         if (r)
 788                 return r;
 789
 790         r = apply_bops(smm);
 791         if (r) {
 792                 DMERR("%s: apply_bops failed", __func__);
 793                 return r;
 794         }
 795
 796         return sm_metadata_commit(sm);
 797 }
 798
 799 int dm_sm_metadata_open(struct dm_space_map *sm,
 800                         struct dm_transaction_manager *tm,
 801                         void *root_le, size_t len)
 802 {
 803         int r;
 804         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 805
 806         r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
 807         if (r)
 808                 return r;
 809
 810         smm->begin = 0;
 811         smm->recursion_count = 0;
 812         smm->allocated_this_transaction = 0;
 813         brb_init(&smm->uncommitted);
 814         threshold_init(&smm->threshold);
 815
 816         memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
 817         return 0;
 818 }