root/drivers/md/persistent-data/dm-space-map-metadata.c

DEFINITIONS

1. threshold_init
2. set_threshold
3. below_threshold
4. threshold_already_triggered
5. check_threshold
6. brb_init
7. brb_empty
8. brb_next
9. brb_push
10. brb_peek
11. brb_pop
12. add_bop
13. commit_bop
14. in
15. apply_bops
16. out
17. combine_errors
18. recursing
19. sm_metadata_destroy
20. sm_metadata_get_nr_blocks
21. sm_metadata_get_nr_free
22. sm_metadata_get_count
23. sm_metadata_count_is_more_than_one
24. sm_metadata_set_count
25. sm_metadata_inc_block
26. sm_metadata_dec_block
27. sm_metadata_new_block_
28. sm_metadata_new_block
29. sm_metadata_commit
30. sm_metadata_register_threshold_callback
31. sm_metadata_root_size
32. sm_metadata_copy_root
33. sm_bootstrap_destroy
34. sm_bootstrap_extend
35. sm_bootstrap_get_nr_blocks
36. sm_bootstrap_get_nr_free
37. sm_bootstrap_get_count
38. sm_bootstrap_count_is_more_than_one
39. sm_bootstrap_set_count
40. sm_bootstrap_new_block
41. sm_bootstrap_inc_block
42. sm_bootstrap_dec_block
43. sm_bootstrap_commit
44. sm_bootstrap_root_size
45. sm_bootstrap_copy_root
46. sm_metadata_extend
47. dm_sm_metadata_init
48. dm_sm_metadata_create
49. dm_sm_metadata_open

   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 #include <linux/kernel.h>
  15 
  16 #define DM_MSG_PREFIX "space map metadata"
  17 
  18 /*----------------------------------------------------------------*/
  19 
  20 /*
  21  * An edge triggered threshold.
  22  */
  23 struct threshold {
  24         bool threshold_set;
  25         bool value_set;
  26         dm_block_t threshold;
  27         dm_block_t current_value;
  28         dm_sm_threshold_fn fn;
  29         void *context;
  30 };
  31 
  32 static void threshold_init(struct threshold *t)
  33 {
  34         t->threshold_set = false;
  35         t->value_set = false;
  36 }
  37 
  38 static void set_threshold(struct threshold *t, dm_block_t value,
  39                           dm_sm_threshold_fn fn, void *context)
  40 {
  41         t->threshold_set = true;
  42         t->threshold = value;
  43         t->fn = fn;
  44         t->context = context;
  45 }
  46 
  47 static bool below_threshold(struct threshold *t, dm_block_t value)
  48 {
  49         return t->threshold_set && value <= t->threshold;
  50 }
  51 
  52 static bool threshold_already_triggered(struct threshold *t)
  53 {
  54         return t->value_set && below_threshold(t, t->current_value);
  55 }
  56 
  57 static void check_threshold(struct threshold *t, dm_block_t value)
  58 {
  59         if (below_threshold(t, value) &&
  60             !threshold_already_triggered(t))
  61                 t->fn(t->context);
  62 
  63         t->value_set = true;
  64         t->current_value = value;
  65 }
  66 
  67 /*----------------------------------------------------------------*/
  68 
  69 /*
  70  * Space map interface.
  71  *
  72  * The low level disk format is written using the standard btree and
  73  * transaction manager.  This means that performing disk operations may
  74  * cause us to recurse into the space map in order to allocate new blocks.
  75  * For this reason we have a pool of pre-allocated blocks large enough to
  76  * service any metadata_ll_disk operation.
  77  */
  78 
  79 /*
  80  * FIXME: we should calculate this based on the size of the device.
  81  * Only the metadata space map needs this functionality.
  82  */
  83 #define MAX_RECURSIVE_ALLOCATIONS 1024
  84 
  85 enum block_op_type {
  86         BOP_INC,
  87         BOP_DEC
  88 };
  89 
  90 struct block_op {
  91         enum block_op_type type;
  92         dm_block_t block;
  93 };
  94 
  95 struct bop_ring_buffer {
  96         unsigned begin;
  97         unsigned end;
  98         struct block_op bops[MAX_RECURSIVE_ALLOCATIONS + 1];
  99 };
 100 
 101 static void brb_init(struct bop_ring_buffer *brb)
 102 {
 103         brb->begin = 0;
 104         brb->end = 0;
 105 }
 106 
 107 static bool brb_empty(struct bop_ring_buffer *brb)
 108 {
 109         return brb->begin == brb->end;
 110 }
 111 
 112 static unsigned brb_next(struct bop_ring_buffer *brb, unsigned old)
 113 {
 114         unsigned r = old + 1;
 115         return r >= ARRAY_SIZE(brb->bops) ? 0 : r;
 116 }
 117 
 118 static int brb_push(struct bop_ring_buffer *brb,
 119                     enum block_op_type type, dm_block_t b)
 120 {
 121         struct block_op *bop;
 122         unsigned next = brb_next(brb, brb->end);
 123 
 124         /*
 125          * We don't allow the last bop to be filled, this way we can
 126          * differentiate between full and empty.
 127          */
 128         if (next == brb->begin)
 129                 return -ENOMEM;
 130 
 131         bop = brb->bops + brb->end;
 132         bop->type = type;
 133         bop->block = b;
 134 
 135         brb->end = next;
 136 
 137         return 0;
 138 }
 139 
 140 static int brb_peek(struct bop_ring_buffer *brb, struct block_op *result)
 141 {
 142         struct block_op *bop;
 143 
 144         if (brb_empty(brb))
 145                 return -ENODATA;
 146 
 147         bop = brb->bops + brb->begin;
 148         result->type = bop->type;
 149         result->block = bop->block;
 150 
 151         return 0;
 152 }
 153 
 154 static int brb_pop(struct bop_ring_buffer *brb)
 155 {
 156         if (brb_empty(brb))
 157                 return -ENODATA;
 158 
 159         brb->begin = brb_next(brb, brb->begin);
 160 
 161         return 0;
 162 }
 163 
 164 /*----------------------------------------------------------------*/
 165 
 166 struct sm_metadata {
 167         struct dm_space_map sm;
 168 
 169         struct ll_disk ll;
 170         struct ll_disk old_ll;
 171 
 172         dm_block_t begin;
 173 
 174         unsigned recursion_count;
 175         unsigned allocated_this_transaction;
 176         struct bop_ring_buffer uncommitted;
 177 
 178         struct threshold threshold;
 179 };
 180 
 181 static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
 182 {
 183         int r = brb_push(&smm->uncommitted, type, b);
 184 
 185         if (r) {
 186                 DMERR("too many recursive allocations");
 187                 return -ENOMEM;
 188         }
 189 
 190         return 0;
 191 }
 192 
 193 static int commit_bop(struct sm_metadata *smm, struct block_op *op)
 194 {
 195         int r = 0;
 196         enum allocation_event ev;
 197 
 198         switch (op->type) {
 199         case BOP_INC:
 200                 r = sm_ll_inc(&smm->ll, op->block, &ev);
 201                 break;
 202 
 203         case BOP_DEC:
 204                 r = sm_ll_dec(&smm->ll, op->block, &ev);
 205                 break;
 206         }
 207 
 208         return r;
 209 }
 210 
 211 static void in(struct sm_metadata *smm)
 212 {
 213         smm->recursion_count++;
 214 }
 215 
 216 static int apply_bops(struct sm_metadata *smm)
 217 {
 218         int r = 0;
 219 
 220         while (!brb_empty(&smm->uncommitted)) {
 221                 struct block_op bop;
 222 
 223                 r = brb_peek(&smm->uncommitted, &bop);
 224                 if (r) {
 225                         DMERR("bug in bop ring buffer");
 226                         break;
 227                 }
 228 
 229                 r = commit_bop(smm, &bop);
 230                 if (r)
 231                         break;
 232 
 233                 brb_pop(&smm->uncommitted);
 234         }
 235 
 236         return r;
 237 }
 238 
 239 static int out(struct sm_metadata *smm)
 240 {
 241         int r = 0;
 242 
 243         /*
 244          * If we're not recursing then very bad things are happening.
 245          */
 246         if (!smm->recursion_count) {
 247                 DMERR("lost track of recursion depth");
 248                 return -ENOMEM;
 249         }
 250 
 251         if (smm->recursion_count == 1)
 252                 r = apply_bops(smm);
 253 
 254         smm->recursion_count--;
 255 
 256         return r;
 257 }
 258 
 259 /*
 260  * When using the out() function above, we often want to combine an error
 261  * code for the operation run in the recursive context with that from
 262  * out().
 263  */
 264 static int combine_errors(int r1, int r2)
 265 {
 266         return r1 ? r1 : r2;
 267 }
 268 
 269 static int recursing(struct sm_metadata *smm)
 270 {
 271         return smm->recursion_count;
 272 }
 273 
 274 static void sm_metadata_destroy(struct dm_space_map *sm)
 275 {
 276         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 277 
 278         kfree(smm);
 279 }
 280 
 281 static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
 282 {
 283         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 284 
 285         *count = smm->ll.nr_blocks;
 286 
 287         return 0;
 288 }
 289 
 290 static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
 291 {
 292         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 293 
 294         *count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
 295                  smm->allocated_this_transaction;
 296 
 297         return 0;
 298 }
 299 
 300 static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
 301                                  uint32_t *result)
 302 {
 303         int r;
 304         unsigned i;
 305         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 306         unsigned adjustment = 0;
 307 
 308         /*
 309          * We may have some uncommitted adjustments to add.  This list
 310          * should always be really short.
 311          */
 312         for (i = smm->uncommitted.begin;
 313              i != smm->uncommitted.end;
 314              i = brb_next(&smm->uncommitted, i)) {
 315                 struct block_op *op = smm->uncommitted.bops + i;
 316 
 317                 if (op->block != b)
 318                         continue;
 319 
 320                 switch (op->type) {
 321                 case BOP_INC:
 322                         adjustment++;
 323                         break;
 324 
 325                 case BOP_DEC:
 326                         adjustment--;
 327                         break;
 328                 }
 329         }
 330 
 331         r = sm_ll_lookup(&smm->ll, b, result);
 332         if (r)
 333                 return r;
 334 
 335         *result += adjustment;
 336 
 337         return 0;
 338 }
 339 
 340 static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
 341                                               dm_block_t b, int *result)
 342 {
 343         int r, adjustment = 0;
 344         unsigned i;
 345         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 346         uint32_t rc;
 347 
 348         /*
 349          * We may have some uncommitted adjustments to add.  This list
 350          * should always be really short.
 351          */
 352         for (i = smm->uncommitted.begin;
 353              i != smm->uncommitted.end;
 354              i = brb_next(&smm->uncommitted, i)) {
 355 
 356                 struct block_op *op = smm->uncommitted.bops + i;
 357 
 358                 if (op->block != b)
 359                         continue;
 360 
 361                 switch (op->type) {
 362                 case BOP_INC:
 363                         adjustment++;
 364                         break;
 365 
 366                 case BOP_DEC:
 367                         adjustment--;
 368                         break;
 369                 }
 370         }
 371 
 372         if (adjustment > 1) {
 373                 *result = 1;
 374                 return 0;
 375         }
 376 
 377         r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
 378         if (r)
 379                 return r;
 380 
 381         if (rc == 3)
 382                 /*
 383                  * We err on the side of caution, and always return true.
 384                  */
 385                 *result = 1;
 386         else
 387                 *result = rc + adjustment > 1;
 388 
 389         return 0;
 390 }
 391 
 392 static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
 393                                  uint32_t count)
 394 {
 395         int r, r2;
 396         enum allocation_event ev;
 397         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 398 
 399         if (smm->recursion_count) {
 400                 DMERR("cannot recurse set_count()");
 401                 return -EINVAL;
 402         }
 403 
 404         in(smm);
 405         r = sm_ll_insert(&smm->ll, b, count, &ev);
 406         r2 = out(smm);
 407 
 408         return combine_errors(r, r2);
 409 }
 410 
 411 static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b)
 412 {
 413         int r, r2 = 0;
 414         enum allocation_event ev;
 415         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 416 
 417         if (recursing(smm))
 418                 r = add_bop(smm, BOP_INC, b);
 419         else {
 420                 in(smm);
 421                 r = sm_ll_inc(&smm->ll, b, &ev);
 422                 r2 = out(smm);
 423         }
 424 
 425         return combine_errors(r, r2);
 426 }
 427 
 428 static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b)
 429 {
 430         int r, r2 = 0;
 431         enum allocation_event ev;
 432         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 433 
 434         if (recursing(smm))
 435                 r = add_bop(smm, BOP_DEC, b);
 436         else {
 437                 in(smm);
 438                 r = sm_ll_dec(&smm->ll, b, &ev);
 439                 r2 = out(smm);
 440         }
 441 
 442         return combine_errors(r, r2);
 443 }
 444 
 445 static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
 446 {
 447         int r, r2 = 0;
 448         enum allocation_event ev;
 449         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 450 
 451         /*
 452          * Any block we allocate has to be free in both the old and current ll.
 453          */
 454         r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, smm->begin, smm->ll.nr_blocks, b);
 455         if (r)
 456                 return r;
 457 
 458         smm->begin = *b + 1;
 459 
 460         if (recursing(smm))
 461                 r = add_bop(smm, BOP_INC, *b);
 462         else {
 463                 in(smm);
 464                 r = sm_ll_inc(&smm->ll, *b, &ev);
 465                 r2 = out(smm);
 466         }
 467 
 468         if (!r)
 469                 smm->allocated_this_transaction++;
 470 
 471         return combine_errors(r, r2);
 472 }
 473 
 474 static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
 475 {
 476         dm_block_t count;
 477         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 478 
 479         int r = sm_metadata_new_block_(sm, b);
 480         if (r) {
 481                 DMERR_LIMIT("unable to allocate new metadata block");
 482                 return r;
 483         }
 484 
 485         r = sm_metadata_get_nr_free(sm, &count);
 486         if (r) {
 487                 DMERR_LIMIT("couldn't get free block count");
 488                 return r;
 489         }
 490 
 491         check_threshold(&smm->threshold, count);
 492 
 493         return r;
 494 }
 495 
 496 static int sm_metadata_commit(struct dm_space_map *sm)
 497 {
 498         int r;
 499         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 500 
 501         r = sm_ll_commit(&smm->ll);
 502         if (r)
 503                 return r;
 504 
 505         memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
 506         smm->begin = 0;
 507         smm->allocated_this_transaction = 0;
 508 
 509         return 0;
 510 }
 511 
 512 static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
 513                                                    dm_block_t threshold,
 514                                                    dm_sm_threshold_fn fn,
 515                                                    void *context)
 516 {
 517         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 518 
 519         set_threshold(&smm->threshold, threshold, fn, context);
 520 
 521         return 0;
 522 }
 523 
 524 static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
 525 {
 526         *result = sizeof(struct disk_sm_root);
 527 
 528         return 0;
 529 }
 530 
 531 static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
 532 {
 533         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 534         struct disk_sm_root root_le;
 535 
 536         root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
 537         root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
 538         root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
 539         root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
 540 
 541         if (max < sizeof(root_le))
 542                 return -ENOSPC;
 543 
 544         memcpy(where_le, &root_le, sizeof(root_le));
 545 
 546         return 0;
 547 }
 548 
 549 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks);
 550 
 551 static const struct dm_space_map ops = {
 552         .destroy = sm_metadata_destroy,
 553         .extend = sm_metadata_extend,
 554         .get_nr_blocks = sm_metadata_get_nr_blocks,
 555         .get_nr_free = sm_metadata_get_nr_free,
 556         .get_count = sm_metadata_get_count,
 557         .count_is_more_than_one = sm_metadata_count_is_more_than_one,
 558         .set_count = sm_metadata_set_count,
 559         .inc_block = sm_metadata_inc_block,
 560         .dec_block = sm_metadata_dec_block,
 561         .new_block = sm_metadata_new_block,
 562         .commit = sm_metadata_commit,
 563         .root_size = sm_metadata_root_size,
 564         .copy_root = sm_metadata_copy_root,
 565         .register_threshold_callback = sm_metadata_register_threshold_callback
 566 };
 567 
 568 /*----------------------------------------------------------------*/
 569 
 570 /*
 571  * When a new space map is created that manages its own space.  We use
 572  * this tiny bootstrap allocator.
 573  */
 574 static void sm_bootstrap_destroy(struct dm_space_map *sm)
 575 {
 576 }
 577 
 578 static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 579 {
 580         DMERR("bootstrap doesn't support extend");
 581 
 582         return -EINVAL;
 583 }
 584 
 585 static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
 586 {
 587         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 588 
 589         *count = smm->ll.nr_blocks;
 590 
 591         return 0;
 592 }
 593 
 594 static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
 595 {
 596         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 597 
 598         *count = smm->ll.nr_blocks - smm->begin;
 599 
 600         return 0;
 601 }
 602 
 603 static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
 604                                   uint32_t *result)
 605 {
 606         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 607 
 608         *result = (b < smm->begin) ? 1 : 0;
 609 
 610         return 0;
 611 }
 612 
 613 static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
 614                                                dm_block_t b, int *result)
 615 {
 616         *result = 0;
 617 
 618         return 0;
 619 }
 620 
 621 static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
 622                                   uint32_t count)
 623 {
 624         DMERR("bootstrap doesn't support set_count");
 625 
 626         return -EINVAL;
 627 }
 628 
 629 static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
 630 {
 631         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 632 
 633         /*
 634          * We know the entire device is unused.
 635          */
 636         if (smm->begin == smm->ll.nr_blocks)
 637                 return -ENOSPC;
 638 
 639         *b = smm->begin++;
 640 
 641         return 0;
 642 }
 643 
 644 static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b)
 645 {
 646         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 647 
 648         return add_bop(smm, BOP_INC, b);
 649 }
 650 
 651 static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b)
 652 {
 653         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 654 
 655         return add_bop(smm, BOP_DEC, b);
 656 }
 657 
 658 static int sm_bootstrap_commit(struct dm_space_map *sm)
 659 {
 660         return 0;
 661 }
 662 
 663 static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
 664 {
 665         DMERR("bootstrap doesn't support root_size");
 666 
 667         return -EINVAL;
 668 }
 669 
 670 static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
 671                                   size_t max)
 672 {
 673         DMERR("bootstrap doesn't support copy_root");
 674 
 675         return -EINVAL;
 676 }
 677 
 678 static const struct dm_space_map bootstrap_ops = {
 679         .destroy = sm_bootstrap_destroy,
 680         .extend = sm_bootstrap_extend,
 681         .get_nr_blocks = sm_bootstrap_get_nr_blocks,
 682         .get_nr_free = sm_bootstrap_get_nr_free,
 683         .get_count = sm_bootstrap_get_count,
 684         .count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
 685         .set_count = sm_bootstrap_set_count,
 686         .inc_block = sm_bootstrap_inc_block,
 687         .dec_block = sm_bootstrap_dec_block,
 688         .new_block = sm_bootstrap_new_block,
 689         .commit = sm_bootstrap_commit,
 690         .root_size = sm_bootstrap_root_size,
 691         .copy_root = sm_bootstrap_copy_root,
 692         .register_threshold_callback = NULL
 693 };
 694 
 695 /*----------------------------------------------------------------*/
 696 
 697 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 698 {
 699         int r, i;
 700         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 701         dm_block_t old_len = smm->ll.nr_blocks;
 702 
 703         /*
 704          * Flick into a mode where all blocks get allocated in the new area.
 705          */
 706         smm->begin = old_len;
 707         memcpy(sm, &bootstrap_ops, sizeof(*sm));
 708 
 709         /*
 710          * Extend.
 711          */
 712         r = sm_ll_extend(&smm->ll, extra_blocks);
 713         if (r)
 714                 goto out;
 715 
 716         /*
 717          * We repeatedly increment then commit until the commit doesn't
 718          * allocate any new blocks.
 719          */
 720         do {
 721                 for (i = old_len; !r && i < smm->begin; i++)
 722                         r = add_bop(smm, BOP_INC, i);
 723 
 724                 if (r)
 725                         goto out;
 726 
 727                 old_len = smm->begin;
 728 
 729                 r = apply_bops(smm);
 730                 if (r) {
 731                         DMERR("%s: apply_bops failed", __func__);
 732                         goto out;
 733                 }
 734 
 735                 r = sm_ll_commit(&smm->ll);
 736                 if (r)
 737                         goto out;
 738 
 739         } while (old_len != smm->begin);
 740 
 741 out:
 742         /*
 743          * Switch back to normal behaviour.
 744          */
 745         memcpy(sm, &ops, sizeof(*sm));
 746         return r;
 747 }
 748 
 749 /*----------------------------------------------------------------*/
 750 
 751 struct dm_space_map *dm_sm_metadata_init(void)
 752 {
 753         struct sm_metadata *smm;
 754 
 755         smm = kmalloc(sizeof(*smm), GFP_KERNEL);
 756         if (!smm)
 757                 return ERR_PTR(-ENOMEM);
 758 
 759         memcpy(&smm->sm, &ops, sizeof(smm->sm));
 760 
 761         return &smm->sm;
 762 }
 763 
 764 int dm_sm_metadata_create(struct dm_space_map *sm,
 765                           struct dm_transaction_manager *tm,
 766                           dm_block_t nr_blocks,
 767                           dm_block_t superblock)
 768 {
 769         int r;
 770         dm_block_t i;
 771         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 772 
 773         smm->begin = superblock + 1;
 774         smm->recursion_count = 0;
 775         smm->allocated_this_transaction = 0;
 776         brb_init(&smm->uncommitted);
 777         threshold_init(&smm->threshold);
 778 
 779         memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
 780 
 781         r = sm_ll_new_metadata(&smm->ll, tm);
 782         if (!r) {
 783                 if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
 784                         nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
 785                 r = sm_ll_extend(&smm->ll, nr_blocks);
 786         }
 787         memcpy(&smm->sm, &ops, sizeof(smm->sm));
 788         if (r)
 789                 return r;
 790 
 791         /*
 792          * Now we need to update the newly created data structures with the
 793          * allocated blocks that they were built from.
 794          */
 795         for (i = superblock; !r && i < smm->begin; i++)
 796                 r = add_bop(smm, BOP_INC, i);
 797 
 798         if (r)
 799                 return r;
 800 
 801         r = apply_bops(smm);
 802         if (r) {
 803                 DMERR("%s: apply_bops failed", __func__);
 804                 return r;
 805         }
 806 
 807         return sm_metadata_commit(sm);
 808 }
 809 
 810 int dm_sm_metadata_open(struct dm_space_map *sm,
 811                         struct dm_transaction_manager *tm,
 812                         void *root_le, size_t len)
 813 {
 814         int r;
 815         struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 816 
 817         r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
 818         if (r)
 819                 return r;
 820 
 821         smm->begin = 0;
 822         smm->recursion_count = 0;
 823         smm->allocated_this_transaction = 0;
 824         brb_init(&smm->uncommitted);
 825         threshold_init(&smm->threshold);
 826 
 827         memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
 828         return 0;
 829 }