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_peek(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         return 0;
 151 }
 152
 153 static int brb_pop(struct bop_ring_buffer *brb)
 154 {
 155         if (brb_empty(brb))
 156                 return -ENODATA;
 157
 158         brb->begin = brb_next(brb, brb->begin);
 159
 160         return 0;
 161 }
 162
 163 /*----------------------------------------------------------------*/
 164
 165 struct sm_metadata {
 166         struct dm_space_map sm;
 167
 168         struct ll_disk ll;
 169         struct ll_disk old_ll;
 170
 171         dm_block_t begin;
 172
 173         unsigned recursion_count;
 174         unsigned allocated_this_transaction;
 175         struct bop_ring_buffer uncommitted;
 176
 177         struct threshold threshold;
 178 };
 179
 180 static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
 181 {
 182         int r = brb_push(&smm->uncommitted, type, b);
 183
 184         if (r) {
 185                 DMERR("too many recursive allocations");
 186                 return -ENOMEM;
 187         }
 188
 189         return 0;
 190 }
 191
 192 static int commit_bop(struct sm_metadata *smm, struct block_op *op)
 193 {
 194         int r = 0;
 195         enum allocation_event ev;
 196
 197         switch (op->type) {
 198         case BOP_INC:
 199                 r = sm_ll_inc(&smm->ll, op->block, &ev);
 200                 break;
 201
 202         case BOP_DEC:
 203                 r = sm_ll_dec(&smm->ll, op->block, &ev);
 204                 break;
 205         }
 206
 207         return r;
 208 }
 209
 210 static void in(struct sm_metadata *smm)
 211 {
 212         smm->recursion_count++;
 213 }
 214
 215 static int apply_bops(struct sm_metadata *smm)
 216 {
 217         int r = 0;
 218
 219         while (!brb_empty(&smm->uncommitted)) {
 220                 struct block_op bop;
 221
 222                 r = brb_peek(&smm->uncommitted, &bop);
 223                 if (r) {
 224                         DMERR("bug in bop ring buffer");
 225                         break;
 226                 }
 227
 228                 r = commit_bop(smm, &bop);
 229                 if (r)
 230                         break;
 231
 232                 brb_pop(&smm->uncommitted);
 233         }
 234
 235         return r;
 236 }
 237
 238 static int out(struct sm_metadata *smm)
 239 {
 240         int r = 0;
 241
 242         /*
 243          * If we're not recursing then very bad things are happening.
 244          */
 245         if (!smm->recursion_count) {
 246                 DMERR("lost track of recursion depth");
 247                 return -ENOMEM;
 248         }
 249
 250         if (smm->recursion_count == 1)
 251                 r = apply_bops(smm);
 252
 253         smm->recursion_count--;
 254
 255         return r;
 256 }
 257
 258 /*
 259  * When using the out() function above, we often want to combine an error
 260  * code for the operation run in the recursive context with that from
 261  * out().
 262  */
 263 static int combine_errors(int r1, int r2)
 264 {
 265         return r1 ? r1 : r2;
 266 }
 267
 268 static int recursing(struct sm_metadata *smm)
 269 {
 270         return smm->recursion_count;
 271 }
 272
 273 static void sm_metadata_destroy(struct dm_space_map *sm)
 274 {
 275         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 276
 277         kfree(smm);
 278 }
 279
 280 static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
 281 {
 282         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 283
 284         *count = smm->ll.nr_blocks;
 285
 286         return 0;
 287 }
 288
 289 static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
 290 {
 291         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 292
 293         *count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
 294                  smm->allocated_this_transaction;
 295
 296         return 0;
 297 }
 298
 299 static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
 300                                  uint32_t *result)
 301 {
 302         int r;
 303         unsigned i;
 304         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 305         unsigned adjustment = 0;
 306
 307         /*
 308          * We may have some uncommitted adjustments to add.  This list
 309          * should always be really short.
 310          */
 311         for (i = smm->uncommitted.begin;
 312              i != smm->uncommitted.end;
 313              i = brb_next(&smm->uncommitted, i)) {
 314                 struct block_op *op = smm->uncommitted.bops + i;
 315
 316                 if (op->block != b)
 317                         continue;
 318
 319                 switch (op->type) {
 320                 case BOP_INC:
 321                         adjustment++;
 322                         break;
 323
 324                 case BOP_DEC:
 325                         adjustment--;
 326                         break;
 327                 }
 328         }
 329
 330         r = sm_ll_lookup(&smm->ll, b, result);
 331         if (r)
 332                 return r;
 333
 334         *result += adjustment;
 335
 336         return 0;
 337 }
 338
 339 static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
 340                                               dm_block_t b, int *result)
 341 {
 342         int r, adjustment = 0;
 343         unsigned i;
 344         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 345         uint32_t rc;
 346
 347         /*
 348          * We may have some uncommitted adjustments to add.  This list
 349          * should always be really short.
 350          */
 351         for (i = smm->uncommitted.begin;
 352              i != smm->uncommitted.end;
 353              i = brb_next(&smm->uncommitted, i)) {
 354
 355                 struct block_op *op = smm->uncommitted.bops + i;
 356
 357                 if (op->block != b)
 358                         continue;
 359
 360                 switch (op->type) {
 361                 case BOP_INC:
 362                         adjustment++;
 363                         break;
 364
 365                 case BOP_DEC:
 366                         adjustment--;
 367                         break;
 368                 }
 369         }
 370
 371         if (adjustment > 1) {
 372                 *result = 1;
 373                 return 0;
 374         }
 375
 376         r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
 377         if (r)
 378                 return r;
 379
 380         if (rc == 3)
 381                 /*
 382                  * We err on the side of caution, and always return true.
 383                  */
 384                 *result = 1;
 385         else
 386                 *result = rc + adjustment > 1;
 387
 388         return 0;
 389 }
 390
 391 static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
 392                                  uint32_t count)
 393 {
 394         int r, r2;
 395         enum allocation_event ev;
 396         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 397
 398         if (smm->recursion_count) {
 399                 DMERR("cannot recurse set_count()");
 400                 return -EINVAL;
 401         }
 402
 403         in(smm);
 404         r = sm_ll_insert(&smm->ll, b, count, &ev);
 405         r2 = out(smm);
 406
 407         return combine_errors(r, r2);
 408 }
 409
 410 static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b)
 411 {
 412         int r, r2 = 0;
 413         enum allocation_event ev;
 414         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 415
 416         if (recursing(smm))
 417                 r = add_bop(smm, BOP_INC, b);
 418         else {
 419                 in(smm);
 420                 r = sm_ll_inc(&smm->ll, b, &ev);
 421                 r2 = out(smm);
 422         }
 423
 424         return combine_errors(r, r2);
 425 }
 426
 427 static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b)
 428 {
 429         int r, r2 = 0;
 430         enum allocation_event ev;
 431         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 432
 433         if (recursing(smm))
 434                 r = add_bop(smm, BOP_DEC, b);
 435         else {
 436                 in(smm);
 437                 r = sm_ll_dec(&smm->ll, b, &ev);
 438                 r2 = out(smm);
 439         }
 440
 441         return combine_errors(r, r2);
 442 }
 443
 444 static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
 445 {
 446         int r, r2 = 0;
 447         enum allocation_event ev;
 448         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 449
 450         /*
 451          * Any block we allocate has to be free in both the old and current ll.
 452          */
 453         r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, smm->begin, smm->ll.nr_blocks, b);
 454         if (r == -ENOSPC) {
 455                 /*
 456                  * There's no free block between smm->begin and the end of the metadata device.
 457                  * We search before smm->begin in case something has been freed.
 458                  */
 459                 r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, 0, smm->begin, b);
 460         }
 461
 462         if (r)
 463                 return r;
 464
 465         smm->begin = *b + 1;
 466
 467         if (recursing(smm))
 468                 r = add_bop(smm, BOP_INC, *b);
 469         else {
 470                 in(smm);
 471                 r = sm_ll_inc(&smm->ll, *b, &ev);
 472                 r2 = out(smm);
 473         }
 474
 475         if (!r)
 476                 smm->allocated_this_transaction++;
 477
 478         return combine_errors(r, r2);
 479 }
 480
 481 static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
 482 {
 483         dm_block_t count;
 484         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 485
 486         int r = sm_metadata_new_block_(sm, b);
 487         if (r) {
 488                 DMERR_LIMIT("unable to allocate new metadata block");
 489                 return r;
 490         }
 491
 492         r = sm_metadata_get_nr_free(sm, &count);
 493         if (r) {
 494                 DMERR_LIMIT("couldn't get free block count");
 495                 return r;
 496         }
 497
 498         check_threshold(&smm->threshold, count);
 499
 500         return r;
 501 }
 502
 503 static int sm_metadata_commit(struct dm_space_map *sm)
 504 {
 505         int r;
 506         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 507
 508         r = sm_ll_commit(&smm->ll);
 509         if (r)
 510                 return r;
 511
 512         memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
 513         smm->allocated_this_transaction = 0;
 514
 515         return 0;
 516 }
 517
 518 static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
 519                                                    dm_block_t threshold,
 520                                                    dm_sm_threshold_fn fn,
 521                                                    void *context)
 522 {
 523         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 524
 525         set_threshold(&smm->threshold, threshold, fn, context);
 526
 527         return 0;
 528 }
 529
 530 static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
 531 {
 532         *result = sizeof(struct disk_sm_root);
 533
 534         return 0;
 535 }
 536
 537 static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
 538 {
 539         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 540         struct disk_sm_root root_le;
 541
 542         root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
 543         root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
 544         root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
 545         root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
 546
 547         if (max < sizeof(root_le))
 548                 return -ENOSPC;
 549
 550         memcpy(where_le, &root_le, sizeof(root_le));
 551
 552         return 0;
 553 }
 554
 555 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks);
 556
 557 static struct dm_space_map ops = {
 558         .destroy = sm_metadata_destroy,
 559         .extend = sm_metadata_extend,
 560         .get_nr_blocks = sm_metadata_get_nr_blocks,
 561         .get_nr_free = sm_metadata_get_nr_free,
 562         .get_count = sm_metadata_get_count,
 563         .count_is_more_than_one = sm_metadata_count_is_more_than_one,
 564         .set_count = sm_metadata_set_count,
 565         .inc_block = sm_metadata_inc_block,
 566         .dec_block = sm_metadata_dec_block,
 567         .new_block = sm_metadata_new_block,
 568         .commit = sm_metadata_commit,
 569         .root_size = sm_metadata_root_size,
 570         .copy_root = sm_metadata_copy_root,
 571         .register_threshold_callback = sm_metadata_register_threshold_callback
 572 };
 573
 574 /*----------------------------------------------------------------*/
 575
 576 /*
 577  * When a new space map is created that manages its own space.  We use
 578  * this tiny bootstrap allocator.
 579  */
 580 static void sm_bootstrap_destroy(struct dm_space_map *sm)
 581 {
 582 }
 583
 584 static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 585 {
 586         DMERR("bootstrap doesn't support extend");
 587
 588         return -EINVAL;
 589 }
 590
 591 static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
 592 {
 593         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 594
 595         *count = smm->ll.nr_blocks;
 596
 597         return 0;
 598 }
 599
 600 static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
 601 {
 602         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 603
 604         *count = smm->ll.nr_blocks - smm->begin;
 605
 606         return 0;
 607 }
 608
 609 static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
 610                                   uint32_t *result)
 611 {
 612         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 613
 614         *result = (b < smm->begin) ? 1 : 0;
 615
 616         return 0;
 617 }
 618
 619 static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
 620                                                dm_block_t b, int *result)
 621 {
 622         *result = 0;
 623
 624         return 0;
 625 }
 626
 627 static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
 628                                   uint32_t count)
 629 {
 630         DMERR("bootstrap doesn't support set_count");
 631
 632         return -EINVAL;
 633 }
 634
 635 static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
 636 {
 637         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 638
 639         /*
 640          * We know the entire device is unused.
 641          */
 642         if (smm->begin == smm->ll.nr_blocks)
 643                 return -ENOSPC;
 644
 645         *b = smm->begin++;
 646
 647         return 0;
 648 }
 649
 650 static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b)
 651 {
 652         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 653
 654         return add_bop(smm, BOP_INC, b);
 655 }
 656
 657 static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b)
 658 {
 659         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 660
 661         return add_bop(smm, BOP_DEC, b);
 662 }
 663
 664 static int sm_bootstrap_commit(struct dm_space_map *sm)
 665 {
 666         return 0;
 667 }
 668
 669 static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
 670 {
 671         DMERR("bootstrap doesn't support root_size");
 672
 673         return -EINVAL;
 674 }
 675
 676 static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
 677                                   size_t max)
 678 {
 679         DMERR("bootstrap doesn't support copy_root");
 680
 681         return -EINVAL;
 682 }
 683
 684 static struct dm_space_map bootstrap_ops = {
 685         .destroy = sm_bootstrap_destroy,
 686         .extend = sm_bootstrap_extend,
 687         .get_nr_blocks = sm_bootstrap_get_nr_blocks,
 688         .get_nr_free = sm_bootstrap_get_nr_free,
 689         .get_count = sm_bootstrap_get_count,
 690         .count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
 691         .set_count = sm_bootstrap_set_count,
 692         .inc_block = sm_bootstrap_inc_block,
 693         .dec_block = sm_bootstrap_dec_block,
 694         .new_block = sm_bootstrap_new_block,
 695         .commit = sm_bootstrap_commit,
 696         .root_size = sm_bootstrap_root_size,
 697         .copy_root = sm_bootstrap_copy_root,
 698         .register_threshold_callback = NULL
 699 };
 700
 701 /*----------------------------------------------------------------*/
 702
 703 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 704 {
 705         int r, i;
 706         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 707         dm_block_t old_len = smm->ll.nr_blocks;
 708
 709         /*
 710          * Flick into a mode where all blocks get allocated in the new area.
 711          */
 712         smm->begin = old_len;
 713         memcpy(sm, &bootstrap_ops, sizeof(*sm));
 714
 715         /*
 716          * Extend.
 717          */
 718         r = sm_ll_extend(&smm->ll, extra_blocks);
 719         if (r)
 720                 goto out;
 721
 722         /*
 723          * We repeatedly increment then commit until the commit doesn't
 724          * allocate any new blocks.
 725          */
 726         do {
 727                 for (i = old_len; !r && i < smm->begin; i++)
 728                         r = add_bop(smm, BOP_INC, i);
 729
 730                 if (r)
 731                         goto out;
 732
 733                 old_len = smm->begin;
 734
 735                 r = apply_bops(smm);
 736                 if (r) {
 737                         DMERR("%s: apply_bops failed", __func__);
 738                         goto out;
 739                 }
 740
 741                 r = sm_ll_commit(&smm->ll);
 742                 if (r)
 743                         goto out;
 744
 745         } while (old_len != smm->begin);
 746
 747 out:
 748         /*
 749          * Switch back to normal behaviour.
 750          */
 751         memcpy(sm, &ops, sizeof(*sm));
 752         return r;
 753 }
 754
 755 /*----------------------------------------------------------------*/
 756
 757 struct dm_space_map *dm_sm_metadata_init(void)
 758 {
 759         struct sm_metadata *smm;
 760
 761         smm = kmalloc(sizeof(*smm), GFP_KERNEL);
 762         if (!smm)
 763                 return ERR_PTR(-ENOMEM);
 764
 765         memcpy(&smm->sm, &ops, sizeof(smm->sm));
 766
 767         return &smm->sm;
 768 }
 769
 770 int dm_sm_metadata_create(struct dm_space_map *sm,
 771                           struct dm_transaction_manager *tm,
 772                           dm_block_t nr_blocks,
 773                           dm_block_t superblock)
 774 {
 775         int r;
 776         dm_block_t i;
 777         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 778
 779         smm->begin = superblock + 1;
 780         smm->recursion_count = 0;
 781         smm->allocated_this_transaction = 0;
 782         brb_init(&smm->uncommitted);
 783         threshold_init(&smm->threshold);
 784
 785         memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
 786
 787         r = sm_ll_new_metadata(&smm->ll, tm);
 788         if (!r) {
 789                 if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
 790                         nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
 791                 r = sm_ll_extend(&smm->ll, nr_blocks);
 792         }
 793         memcpy(&smm->sm, &ops, sizeof(smm->sm));
 794         if (r)
 795                 return r;
 796
 797         /*
 798          * Now we need to update the newly created data structures with the
 799          * allocated blocks that they were built from.
 800          */
 801         for (i = superblock; !r && i < smm->begin; i++)
 802                 r = add_bop(smm, BOP_INC, i);
 803
 804         if (r)
 805                 return r;
 806
 807         r = apply_bops(smm);
 808         if (r) {
 809                 DMERR("%s: apply_bops failed", __func__);
 810                 return r;
 811         }
 812
 813         return sm_metadata_commit(sm);
 814 }
 815
 816 int dm_sm_metadata_open(struct dm_space_map *sm,
 817                         struct dm_transaction_manager *tm,
 818                         void *root_le, size_t len)
 819 {
 820         int r;
 821         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 822
 823         r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
 824         if (r)
 825                 return r;
 826
 827         smm->begin = 0;
 828         smm->recursion_count = 0;
 829         smm->allocated_this_transaction = 0;
 830         brb_init(&smm->uncommitted);
 831         threshold_init(&smm->threshold);
 832
 833         memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
 834         return 0;
 835 }