drivers/md/dm-cache-metadata.c

   1 /*
   2  * Copyright (C) 2012 Red Hat, Inc.
   3  *
   4  * This file is released under the GPL.
   5  */
   6
   7 #include "dm-cache-metadata.h"
   8
   9 #include "persistent-data/dm-array.h"
  10 #include "persistent-data/dm-bitset.h"
  11 #include "persistent-data/dm-space-map.h"
  12 #include "persistent-data/dm-space-map-disk.h"
  13 #include "persistent-data/dm-transaction-manager.h"
  14
  15 #include <linux/device-mapper.h>
  16
  17 /*----------------------------------------------------------------*/
  18
  19 #define DM_MSG_PREFIX   "cache metadata"
  20
  21 #define CACHE_SUPERBLOCK_MAGIC 06142003
  22 #define CACHE_SUPERBLOCK_LOCATION 0
  23
  24 /*
  25  * defines a range of metadata versions that this module can handle.
  26  */
  27 #define MIN_CACHE_VERSION 1
  28 #define MAX_CACHE_VERSION 1
  29
  30 #define CACHE_METADATA_CACHE_SIZE 64
  31
  32 /*
  33  *  3 for btree insert +
  34  *  2 for btree lookup used within space map
  35  */
  36 #define CACHE_MAX_CONCURRENT_LOCKS 5
  37 #define SPACE_MAP_ROOT_SIZE 128
  38
  39 enum superblock_flag_bits {
  40         /* for spotting crashes that would invalidate the dirty bitset */
  41         CLEAN_SHUTDOWN,
  42 };
  43
  44 /*
  45  * Each mapping from cache block -> origin block carries a set of flags.
  46  */
  47 enum mapping_bits {
  48         /*
  49          * A valid mapping.  Because we're using an array we clear this
  50          * flag for an non existant mapping.
  51          */
  52         M_VALID = 1,
  53
  54         /*
  55          * The data on the cache is different from that on the origin.
  56          */
  57         M_DIRTY = 2
  58 };
  59
  60 struct cache_disk_superblock {
  61         __le32 csum;
  62         __le32 flags;
  63         __le64 blocknr;
  64
  65         __u8 uuid[16];
  66         __le64 magic;
  67         __le32 version;
  68
  69         __u8 policy_name[CACHE_POLICY_NAME_SIZE];
  70         __le32 policy_hint_size;
  71
  72         __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
  73         __le64 mapping_root;
  74         __le64 hint_root;
  75
  76         __le64 discard_root;
  77         __le64 discard_block_size;
  78         __le64 discard_nr_blocks;
  79
  80         __le32 data_block_size;
  81         __le32 metadata_block_size;
  82         __le32 cache_blocks;
  83
  84         __le32 compat_flags;
  85         __le32 compat_ro_flags;
  86         __le32 incompat_flags;
  87
  88         __le32 read_hits;
  89         __le32 read_misses;
  90         __le32 write_hits;
  91         __le32 write_misses;
  92
  93         __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
  94 } __packed;
  95
  96 struct dm_cache_metadata {
  97         atomic_t ref_count;
  98         struct list_head list;
  99
 100         struct block_device *bdev;
 101         struct dm_block_manager *bm;
 102         struct dm_space_map *metadata_sm;
 103         struct dm_transaction_manager *tm;
 104
 105         struct dm_array_info info;
 106         struct dm_array_info hint_info;
 107         struct dm_disk_bitset discard_info;
 108
 109         struct rw_semaphore root_lock;
 110         dm_block_t root;
 111         dm_block_t hint_root;
 112         dm_block_t discard_root;
 113
 114         sector_t discard_block_size;
 115         dm_dblock_t discard_nr_blocks;
 116
 117         sector_t data_block_size;
 118         dm_cblock_t cache_blocks;
 119         bool changed:1;
 120         bool clean_when_opened:1;
 121
 122         char policy_name[CACHE_POLICY_NAME_SIZE];
 123         unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
 124         size_t policy_hint_size;
 125         struct dm_cache_statistics stats;
 126
 127         /*
 128          * Reading the space map root can fail, so we read it into this
 129          * buffer before the superblock is locked and updated.
 130          */
 131         __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
 132 };
 133
 134 /*-------------------------------------------------------------------
 135  * superblock validator
 136  *-----------------------------------------------------------------*/
 137
 138 #define SUPERBLOCK_CSUM_XOR 9031977
 139
 140 static void sb_prepare_for_write(struct dm_block_validator *v,
 141                                  struct dm_block *b,
 142                                  size_t sb_block_size)
 143 {
 144         struct cache_disk_superblock *disk_super = dm_block_data(b);
 145
 146         disk_super->blocknr = cpu_to_le64(dm_block_location(b));
 147         disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 148                                                       sb_block_size - sizeof(__le32),
 149                                                       SUPERBLOCK_CSUM_XOR));
 150 }
 151
 152 static int check_metadata_version(struct cache_disk_superblock *disk_super)
 153 {
 154         uint32_t metadata_version = le32_to_cpu(disk_super->version);
 155         if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
 156                 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
 157                       metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
 158                 return -EINVAL;
 159         }
 160
 161         return 0;
 162 }
 163
 164 static int sb_check(struct dm_block_validator *v,
 165                     struct dm_block *b,
 166                     size_t sb_block_size)
 167 {
 168         struct cache_disk_superblock *disk_super = dm_block_data(b);
 169         __le32 csum_le;
 170
 171         if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
 172                 DMERR("sb_check failed: blocknr %llu: wanted %llu",
 173                       le64_to_cpu(disk_super->blocknr),
 174                       (unsigned long long)dm_block_location(b));
 175                 return -ENOTBLK;
 176         }
 177
 178         if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
 179                 DMERR("sb_check failed: magic %llu: wanted %llu",
 180                       le64_to_cpu(disk_super->magic),
 181                       (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
 182                 return -EILSEQ;
 183         }
 184
 185         csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 186                                              sb_block_size - sizeof(__le32),
 187                                              SUPERBLOCK_CSUM_XOR));
 188         if (csum_le != disk_super->csum) {
 189                 DMERR("sb_check failed: csum %u: wanted %u",
 190                       le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
 191                 return -EILSEQ;
 192         }
 193
 194         return check_metadata_version(disk_super);
 195 }
 196
 197 static struct dm_block_validator sb_validator = {
 198         .name = "superblock",
 199         .prepare_for_write = sb_prepare_for_write,
 200         .check = sb_check
 201 };
 202
 203 /*----------------------------------------------------------------*/
 204
 205 static int superblock_read_lock(struct dm_cache_metadata *cmd,
 206                                 struct dm_block **sblock)
 207 {
 208         return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 209                                &sb_validator, sblock);
 210 }
 211
 212 static int superblock_lock_zero(struct dm_cache_metadata *cmd,
 213                                 struct dm_block **sblock)
 214 {
 215         return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 216                                      &sb_validator, sblock);
 217 }
 218
 219 static int superblock_lock(struct dm_cache_metadata *cmd,
 220                            struct dm_block **sblock)
 221 {
 222         return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 223                                 &sb_validator, sblock);
 224 }
 225
 226 /*----------------------------------------------------------------*/
 227
 228 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
 229 {
 230         int r;
 231         unsigned i;
 232         struct dm_block *b;
 233         __le64 *data_le, zero = cpu_to_le64(0);
 234         unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
 235
 236         /*
 237          * We can't use a validator here - it may be all zeroes.
 238          */
 239         r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
 240         if (r)
 241                 return r;
 242
 243         data_le = dm_block_data(b);
 244         *result = true;
 245         for (i = 0; i < sb_block_size; i++) {
 246                 if (data_le[i] != zero) {
 247                         *result = false;
 248                         break;
 249                 }
 250         }
 251
 252         return dm_bm_unlock(b);
 253 }
 254
 255 static void __setup_mapping_info(struct dm_cache_metadata *cmd)
 256 {
 257         struct dm_btree_value_type vt;
 258
 259         vt.context = NULL;
 260         vt.size = sizeof(__le64);
 261         vt.inc = NULL;
 262         vt.dec = NULL;
 263         vt.equal = NULL;
 264         dm_array_info_init(&cmd->info, cmd->tm, &vt);
 265
 266         if (cmd->policy_hint_size) {
 267                 vt.size = sizeof(__le32);
 268                 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
 269         }
 270 }
 271
 272 static int __save_sm_root(struct dm_cache_metadata *cmd)
 273 {
 274         int r;
 275         size_t metadata_len;
 276
 277         r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
 278         if (r < 0)
 279                 return r;
 280
 281         return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
 282                                metadata_len);
 283 }
 284
 285 static void __copy_sm_root(struct dm_cache_metadata *cmd,
 286                            struct cache_disk_superblock *disk_super)
 287 {
 288         memcpy(&disk_super->metadata_space_map_root,
 289                &cmd->metadata_space_map_root,
 290                sizeof(cmd->metadata_space_map_root));
 291 }
 292
 293 static int __write_initial_superblock(struct dm_cache_metadata *cmd)
 294 {
 295         int r;
 296         struct dm_block *sblock;
 297         struct cache_disk_superblock *disk_super;
 298         sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
 299
 300         /* FIXME: see if we can lose the max sectors limit */
 301         if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
 302                 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
 303
 304         r = dm_tm_pre_commit(cmd->tm);
 305         if (r < 0)
 306                 return r;
 307
 308         /*
 309          * dm_sm_copy_root() can fail.  So we need to do it before we start
 310          * updating the superblock.
 311          */
 312         r = __save_sm_root(cmd);
 313         if (r)
 314                 return r;
 315
 316         r = superblock_lock_zero(cmd, &sblock);
 317         if (r)
 318                 return r;
 319
 320         disk_super = dm_block_data(sblock);
 321         disk_super->flags = 0;
 322         memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
 323         disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
 324         disk_super->version = cpu_to_le32(MAX_CACHE_VERSION);
 325         memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
 326         memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
 327         disk_super->policy_hint_size = 0;
 328
 329         __copy_sm_root(cmd, disk_super);
 330
 331         disk_super->mapping_root = cpu_to_le64(cmd->root);
 332         disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 333         disk_super->discard_root = cpu_to_le64(cmd->discard_root);
 334         disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
 335         disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
 336         disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
 337         disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
 338         disk_super->cache_blocks = cpu_to_le32(0);
 339
 340         disk_super->read_hits = cpu_to_le32(0);
 341         disk_super->read_misses = cpu_to_le32(0);
 342         disk_super->write_hits = cpu_to_le32(0);
 343         disk_super->write_misses = cpu_to_le32(0);
 344
 345         return dm_tm_commit(cmd->tm, sblock);
 346 }
 347
 348 static int __format_metadata(struct dm_cache_metadata *cmd)
 349 {
 350         int r;
 351
 352         r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 353                                  &cmd->tm, &cmd->metadata_sm);
 354         if (r < 0) {
 355                 DMERR("tm_create_with_sm failed");
 356                 return r;
 357         }
 358
 359         __setup_mapping_info(cmd);
 360
 361         r = dm_array_empty(&cmd->info, &cmd->root);
 362         if (r < 0)
 363                 goto bad;
 364
 365         dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
 366
 367         r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
 368         if (r < 0)
 369                 goto bad;
 370
 371         cmd->discard_block_size = 0;
 372         cmd->discard_nr_blocks = 0;
 373
 374         r = __write_initial_superblock(cmd);
 375         if (r)
 376                 goto bad;
 377
 378         cmd->clean_when_opened = true;
 379         return 0;
 380
 381 bad:
 382         dm_tm_destroy(cmd->tm);
 383         dm_sm_destroy(cmd->metadata_sm);
 384
 385         return r;
 386 }
 387
 388 static int __check_incompat_features(struct cache_disk_superblock *disk_super,
 389                                      struct dm_cache_metadata *cmd)
 390 {
 391         uint32_t features;
 392
 393         features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
 394         if (features) {
 395                 DMERR("could not access metadata due to unsupported optional features (%lx).",
 396                       (unsigned long)features);
 397                 return -EINVAL;
 398         }
 399
 400         /*
 401          * Check for read-only metadata to skip the following RDWR checks.
 402          */
 403         if (get_disk_ro(cmd->bdev->bd_disk))
 404                 return 0;
 405
 406         features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
 407         if (features) {
 408                 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
 409                       (unsigned long)features);
 410                 return -EINVAL;
 411         }
 412
 413         return 0;
 414 }
 415
 416 static int __open_metadata(struct dm_cache_metadata *cmd)
 417 {
 418         int r;
 419         struct dm_block *sblock;
 420         struct cache_disk_superblock *disk_super;
 421         unsigned long sb_flags;
 422
 423         r = superblock_read_lock(cmd, &sblock);
 424         if (r < 0) {
 425                 DMERR("couldn't read lock superblock");
 426                 return r;
 427         }
 428
 429         disk_super = dm_block_data(sblock);
 430
 431         /* Verify the data block size hasn't changed */
 432         if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
 433                 DMERR("changing the data block size (from %u to %llu) is not supported",
 434                       le32_to_cpu(disk_super->data_block_size),
 435                       (unsigned long long)cmd->data_block_size);
 436                 r = -EINVAL;
 437                 goto bad;
 438         }
 439
 440         r = __check_incompat_features(disk_super, cmd);
 441         if (r < 0)
 442                 goto bad;
 443
 444         r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 445                                disk_super->metadata_space_map_root,
 446                                sizeof(disk_super->metadata_space_map_root),
 447                                &cmd->tm, &cmd->metadata_sm);
 448         if (r < 0) {
 449                 DMERR("tm_open_with_sm failed");
 450                 goto bad;
 451         }
 452
 453         __setup_mapping_info(cmd);
 454         dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
 455         sb_flags = le32_to_cpu(disk_super->flags);
 456         cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
 457         return dm_bm_unlock(sblock);
 458
 459 bad:
 460         dm_bm_unlock(sblock);
 461         return r;
 462 }
 463
 464 static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
 465                                      bool format_device)
 466 {
 467         int r;
 468         bool unformatted = false;
 469
 470         r = __superblock_all_zeroes(cmd->bm, &unformatted);
 471         if (r)
 472                 return r;
 473
 474         if (unformatted)
 475                 return format_device ? __format_metadata(cmd) : -EPERM;
 476
 477         return __open_metadata(cmd);
 478 }
 479
 480 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
 481                                             bool may_format_device)
 482 {
 483         int r;
 484         cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
 485                                           CACHE_METADATA_CACHE_SIZE,
 486                                           CACHE_MAX_CONCURRENT_LOCKS);
 487         if (IS_ERR(cmd->bm)) {
 488                 DMERR("could not create block manager");
 489                 return PTR_ERR(cmd->bm);
 490         }
 491
 492         r = __open_or_format_metadata(cmd, may_format_device);
 493         if (r)
 494                 dm_block_manager_destroy(cmd->bm);
 495
 496         return r;
 497 }
 498
 499 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
 500 {
 501         dm_sm_destroy(cmd->metadata_sm);
 502         dm_tm_destroy(cmd->tm);
 503         dm_block_manager_destroy(cmd->bm);
 504 }
 505
 506 typedef unsigned long (*flags_mutator)(unsigned long);
 507
 508 static void update_flags(struct cache_disk_superblock *disk_super,
 509                          flags_mutator mutator)
 510 {
 511         uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
 512         disk_super->flags = cpu_to_le32(sb_flags);
 513 }
 514
 515 static unsigned long set_clean_shutdown(unsigned long flags)
 516 {
 517         set_bit(CLEAN_SHUTDOWN, &flags);
 518         return flags;
 519 }
 520
 521 static unsigned long clear_clean_shutdown(unsigned long flags)
 522 {
 523         clear_bit(CLEAN_SHUTDOWN, &flags);
 524         return flags;
 525 }
 526
 527 static void read_superblock_fields(struct dm_cache_metadata *cmd,
 528                                    struct cache_disk_superblock *disk_super)
 529 {
 530         cmd->root = le64_to_cpu(disk_super->mapping_root);
 531         cmd->hint_root = le64_to_cpu(disk_super->hint_root);
 532         cmd->discard_root = le64_to_cpu(disk_super->discard_root);
 533         cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
 534         cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
 535         cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
 536         cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
 537         strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
 538         cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
 539         cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
 540         cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
 541         cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
 542
 543         cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
 544         cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
 545         cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
 546         cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
 547
 548         cmd->changed = false;
 549 }
 550
 551 /*
 552  * The mutator updates the superblock flags.
 553  */
 554 static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
 555                                      flags_mutator mutator)
 556 {
 557         int r;
 558         struct cache_disk_superblock *disk_super;
 559         struct dm_block *sblock;
 560
 561         r = superblock_lock(cmd, &sblock);
 562         if (r)
 563                 return r;
 564
 565         disk_super = dm_block_data(sblock);
 566         update_flags(disk_super, mutator);
 567         read_superblock_fields(cmd, disk_super);
 568         dm_bm_unlock(sblock);
 569
 570         return dm_bm_flush(cmd->bm);
 571 }
 572
 573 static int __begin_transaction(struct dm_cache_metadata *cmd)
 574 {
 575         int r;
 576         struct cache_disk_superblock *disk_super;
 577         struct dm_block *sblock;
 578
 579         /*
 580          * We re-read the superblock every time.  Shouldn't need to do this
 581          * really.
 582          */
 583         r = superblock_read_lock(cmd, &sblock);
 584         if (r)
 585                 return r;
 586
 587         disk_super = dm_block_data(sblock);
 588         read_superblock_fields(cmd, disk_super);
 589         dm_bm_unlock(sblock);
 590
 591         return 0;
 592 }
 593
 594 static int __commit_transaction(struct dm_cache_metadata *cmd,
 595                                 flags_mutator mutator)
 596 {
 597         int r;
 598         struct cache_disk_superblock *disk_super;
 599         struct dm_block *sblock;
 600
 601         /*
 602          * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
 603          */
 604         BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
 605
 606         r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
 607                             &cmd->discard_root);
 608         if (r)
 609                 return r;
 610
 611         r = dm_tm_pre_commit(cmd->tm);
 612         if (r < 0)
 613                 return r;
 614
 615         r = __save_sm_root(cmd);
 616         if (r)
 617                 return r;
 618
 619         r = superblock_lock(cmd, &sblock);
 620         if (r)
 621                 return r;
 622
 623         disk_super = dm_block_data(sblock);
 624
 625         if (mutator)
 626                 update_flags(disk_super, mutator);
 627
 628         disk_super->mapping_root = cpu_to_le64(cmd->root);
 629         disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 630         disk_super->discard_root = cpu_to_le64(cmd->discard_root);
 631         disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
 632         disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
 633         disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
 634         strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
 635         disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
 636         disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
 637         disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
 638
 639         disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
 640         disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
 641         disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
 642         disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
 643         __copy_sm_root(cmd, disk_super);
 644
 645         return dm_tm_commit(cmd->tm, sblock);
 646 }
 647
 648 /*----------------------------------------------------------------*/
 649
 650 /*
 651  * The mappings are held in a dm-array that has 64-bit values stored in
 652  * little-endian format.  The index is the cblock, the high 48bits of the
 653  * value are the oblock and the low 16 bit the flags.
 654  */
 655 #define FLAGS_MASK ((1 << 16) - 1)
 656
 657 static __le64 pack_value(dm_oblock_t block, unsigned flags)
 658 {
 659         uint64_t value = from_oblock(block);
 660         value <<= 16;
 661         value = value | (flags & FLAGS_MASK);
 662         return cpu_to_le64(value);
 663 }
 664
 665 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
 666 {
 667         uint64_t value = le64_to_cpu(value_le);
 668         uint64_t b = value >> 16;
 669         *block = to_oblock(b);
 670         *flags = value & FLAGS_MASK;
 671 }
 672
 673 /*----------------------------------------------------------------*/
 674
 675 static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
 676                                                sector_t data_block_size,
 677                                                bool may_format_device,
 678                                                size_t policy_hint_size)
 679 {
 680         int r;
 681         struct dm_cache_metadata *cmd;
 682
 683         cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
 684         if (!cmd) {
 685                 DMERR("could not allocate metadata struct");
 686                 return ERR_PTR(-ENOMEM);
 687         }
 688
 689         atomic_set(&cmd->ref_count, 1);
 690         init_rwsem(&cmd->root_lock);
 691         cmd->bdev = bdev;
 692         cmd->data_block_size = data_block_size;
 693         cmd->cache_blocks = 0;
 694         cmd->policy_hint_size = policy_hint_size;
 695         cmd->changed = true;
 696
 697         r = __create_persistent_data_objects(cmd, may_format_device);
 698         if (r) {
 699                 kfree(cmd);
 700                 return ERR_PTR(r);
 701         }
 702
 703         r = __begin_transaction_flags(cmd, clear_clean_shutdown);
 704         if (r < 0) {
 705                 dm_cache_metadata_close(cmd);
 706                 return ERR_PTR(r);
 707         }
 708
 709         return cmd;
 710 }
 711
 712 /*
 713  * We keep a little list of ref counted metadata objects to prevent two
 714  * different target instances creating separate bufio instances.  This is
 715  * an issue if a table is reloaded before the suspend.
 716  */
 717 static DEFINE_MUTEX(table_lock);
 718 static LIST_HEAD(table);
 719
 720 static struct dm_cache_metadata *lookup(struct block_device *bdev)
 721 {
 722         struct dm_cache_metadata *cmd;
 723
 724         list_for_each_entry(cmd, &table, list)
 725                 if (cmd->bdev == bdev) {
 726                         atomic_inc(&cmd->ref_count);
 727                         return cmd;
 728                 }
 729
 730         return NULL;
 731 }
 732
 733 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
 734                                                 sector_t data_block_size,
 735                                                 bool may_format_device,
 736                                                 size_t policy_hint_size)
 737 {
 738         struct dm_cache_metadata *cmd, *cmd2;
 739
 740         mutex_lock(&table_lock);
 741         cmd = lookup(bdev);
 742         mutex_unlock(&table_lock);
 743
 744         if (cmd)
 745                 return cmd;
 746
 747         cmd = metadata_open(bdev, data_block_size, may_format_device, policy_hint_size);
 748         if (!IS_ERR(cmd)) {
 749                 mutex_lock(&table_lock);
 750                 cmd2 = lookup(bdev);
 751                 if (cmd2) {
 752                         mutex_unlock(&table_lock);
 753                         __destroy_persistent_data_objects(cmd);
 754                         kfree(cmd);
 755                         return cmd2;
 756                 }
 757                 list_add(&cmd->list, &table);
 758                 mutex_unlock(&table_lock);
 759         }
 760
 761         return cmd;
 762 }
 763
 764 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
 765 {
 766         if (cmd->data_block_size != data_block_size) {
 767                 DMERR("data_block_size (%llu) different from that in metadata (%llu)\n",
 768                       (unsigned long long) data_block_size,
 769                       (unsigned long long) cmd->data_block_size);
 770                 return false;
 771         }
 772
 773         return true;
 774 }
 775
 776 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
 777                                                  sector_t data_block_size,
 778                                                  bool may_format_device,
 779                                                  size_t policy_hint_size)
 780 {
 781         struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size,
 782                                                        may_format_device, policy_hint_size);
 783
 784         if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
 785                 dm_cache_metadata_close(cmd);
 786                 return ERR_PTR(-EINVAL);
 787         }
 788
 789         return cmd;
 790 }
 791
 792 void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
 793 {
 794         if (atomic_dec_and_test(&cmd->ref_count)) {
 795                 mutex_lock(&table_lock);
 796                 list_del(&cmd->list);
 797                 mutex_unlock(&table_lock);
 798
 799                 __destroy_persistent_data_objects(cmd);
 800                 kfree(cmd);
 801         }
 802 }
 803
 804 /*
 805  * Checks that the given cache block is either unmapped or clean.
 806  */
 807 static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
 808                                    bool *result)
 809 {
 810         int r;
 811         __le64 value;
 812         dm_oblock_t ob;
 813         unsigned flags;
 814
 815         r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
 816         if (r) {
 817                 DMERR("block_unmapped_or_clean failed");
 818                 return r;
 819         }
 820
 821         unpack_value(value, &ob, &flags);
 822         *result = !((flags & M_VALID) && (flags & M_DIRTY));
 823
 824         return 0;
 825 }
 826
 827 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
 828                                         dm_cblock_t begin, dm_cblock_t end,
 829                                         bool *result)
 830 {
 831         int r;
 832         *result = true;
 833
 834         while (begin != end) {
 835                 r = block_unmapped_or_clean(cmd, begin, result);
 836                 if (r)
 837                         return r;
 838
 839                 if (!*result) {
 840                         DMERR("cache block %llu is dirty",
 841                               (unsigned long long) from_cblock(begin));
 842                         return 0;
 843                 }
 844
 845                 begin = to_cblock(from_cblock(begin) + 1);
 846         }
 847
 848         return 0;
 849 }
 850
 851 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
 852 {
 853         int r;
 854         bool clean;
 855         __le64 null_mapping = pack_value(0, 0);
 856
 857         down_write(&cmd->root_lock);
 858         __dm_bless_for_disk(&null_mapping);
 859
 860         if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
 861                 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
 862                 if (r) {
 863                         __dm_unbless_for_disk(&null_mapping);
 864                         goto out;
 865                 }
 866
 867                 if (!clean) {
 868                         DMERR("unable to shrink cache due to dirty blocks");
 869                         r = -EINVAL;
 870                         __dm_unbless_for_disk(&null_mapping);
 871                         goto out;
 872                 }
 873         }
 874
 875         r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
 876                             from_cblock(new_cache_size),
 877                             &null_mapping, &cmd->root);
 878         if (!r)
 879                 cmd->cache_blocks = new_cache_size;
 880         cmd->changed = true;
 881
 882 out:
 883         up_write(&cmd->root_lock);
 884
 885         return r;
 886 }
 887
 888 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
 889                                    sector_t discard_block_size,
 890                                    dm_dblock_t new_nr_entries)
 891 {
 892         int r;
 893
 894         down_write(&cmd->root_lock);
 895         r = dm_bitset_resize(&cmd->discard_info,
 896                              cmd->discard_root,
 897                              from_dblock(cmd->discard_nr_blocks),
 898                              from_dblock(new_nr_entries),
 899                              false, &cmd->discard_root);
 900         if (!r) {
 901                 cmd->discard_block_size = discard_block_size;
 902                 cmd->discard_nr_blocks = new_nr_entries;
 903         }
 904
 905         cmd->changed = true;
 906         up_write(&cmd->root_lock);
 907
 908         return r;
 909 }
 910
 911 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
 912 {
 913         return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
 914                                  from_dblock(b), &cmd->discard_root);
 915 }
 916
 917 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
 918 {
 919         return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
 920                                    from_dblock(b), &cmd->discard_root);
 921 }
 922
 923 static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
 924                           bool *is_discarded)
 925 {
 926         return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
 927                                   from_dblock(b), &cmd->discard_root,
 928                                   is_discarded);
 929 }
 930
 931 static int __discard(struct dm_cache_metadata *cmd,
 932                      dm_dblock_t dblock, bool discard)
 933 {
 934         int r;
 935
 936         r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
 937         if (r)
 938                 return r;
 939
 940         cmd->changed = true;
 941         return 0;
 942 }
 943
 944 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
 945                          dm_dblock_t dblock, bool discard)
 946 {
 947         int r;
 948
 949         down_write(&cmd->root_lock);
 950         r = __discard(cmd, dblock, discard);
 951         up_write(&cmd->root_lock);
 952
 953         return r;
 954 }
 955
 956 static int __load_discards(struct dm_cache_metadata *cmd,
 957                            load_discard_fn fn, void *context)
 958 {
 959         int r = 0;
 960         dm_block_t b;
 961         bool discard;
 962
 963         for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
 964                 dm_dblock_t dblock = to_dblock(b);
 965
 966                 if (cmd->clean_when_opened) {
 967                         r = __is_discarded(cmd, dblock, &discard);
 968                         if (r)
 969                                 return r;
 970                 } else
 971                         discard = false;
 972
 973                 r = fn(context, cmd->discard_block_size, dblock, discard);
 974                 if (r)
 975                         break;
 976         }
 977
 978         return r;
 979 }
 980
 981 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
 982                            load_discard_fn fn, void *context)
 983 {
 984         int r;
 985
 986         down_read(&cmd->root_lock);
 987         r = __load_discards(cmd, fn, context);
 988         up_read(&cmd->root_lock);
 989
 990         return r;
 991 }
 992
 993 dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd)
 994 {
 995         dm_cblock_t r;
 996
 997         down_read(&cmd->root_lock);
 998         r = cmd->cache_blocks;
 999         up_read(&cmd->root_lock);
1000
1001         return r;
1002 }
1003
1004 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1005 {
1006         int r;
1007         __le64 value = pack_value(0, 0);
1008
1009         __dm_bless_for_disk(&value);
1010         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1011                                &value, &cmd->root);
1012         if (r)
1013                 return r;
1014
1015         cmd->changed = true;
1016         return 0;
1017 }
1018
1019 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1020 {
1021         int r;
1022
1023         down_write(&cmd->root_lock);
1024         r = __remove(cmd, cblock);
1025         up_write(&cmd->root_lock);
1026
1027         return r;
1028 }
1029
1030 static int __insert(struct dm_cache_metadata *cmd,
1031                     dm_cblock_t cblock, dm_oblock_t oblock)
1032 {
1033         int r;
1034         __le64 value = pack_value(oblock, M_VALID);
1035         __dm_bless_for_disk(&value);
1036
1037         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1038                                &value, &cmd->root);
1039         if (r)
1040                 return r;
1041
1042         cmd->changed = true;
1043         return 0;
1044 }
1045
1046 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1047                             dm_cblock_t cblock, dm_oblock_t oblock)
1048 {
1049         int r;
1050
1051         down_write(&cmd->root_lock);
1052         r = __insert(cmd, cblock, oblock);
1053         up_write(&cmd->root_lock);
1054
1055         return r;
1056 }
1057
1058 struct thunk {
1059         load_mapping_fn fn;
1060         void *context;
1061
1062         struct dm_cache_metadata *cmd;
1063         bool respect_dirty_flags;
1064         bool hints_valid;
1065 };
1066
1067 static bool policy_unchanged(struct dm_cache_metadata *cmd,
1068                              struct dm_cache_policy *policy)
1069 {
1070         const char *policy_name = dm_cache_policy_get_name(policy);
1071         const unsigned *policy_version = dm_cache_policy_get_version(policy);
1072         size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1073
1074         /*
1075          * Ensure policy names match.
1076          */
1077         if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1078                 return false;
1079
1080         /*
1081          * Ensure policy major versions match.
1082          */
1083         if (cmd->policy_version[0] != policy_version[0])
1084                 return false;
1085
1086         /*
1087          * Ensure policy hint sizes match.
1088          */
1089         if (cmd->policy_hint_size != policy_hint_size)
1090                 return false;
1091
1092         return true;
1093 }
1094
1095 static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1096 {
1097         return cmd->hint_root && cmd->policy_hint_size;
1098 }
1099
1100 static bool hints_array_available(struct dm_cache_metadata *cmd,
1101                                   struct dm_cache_policy *policy)
1102 {
1103         return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1104                 hints_array_initialized(cmd);
1105 }
1106
1107 static int __load_mapping(void *context, uint64_t cblock, void *leaf)
1108 {
1109         int r = 0;
1110         bool dirty;
1111         __le64 value;
1112         __le32 hint_value = 0;
1113         dm_oblock_t oblock;
1114         unsigned flags;
1115         struct thunk *thunk = context;
1116         struct dm_cache_metadata *cmd = thunk->cmd;
1117
1118         memcpy(&value, leaf, sizeof(value));
1119         unpack_value(value, &oblock, &flags);
1120
1121         if (flags & M_VALID) {
1122                 if (thunk->hints_valid) {
1123                         r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,
1124                                                cblock, &hint_value);
1125                         if (r && r != -ENODATA)
1126                                 return r;
1127                 }
1128
1129                 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;
1130                 r = thunk->fn(thunk->context, oblock, to_cblock(cblock),
1131                               dirty, le32_to_cpu(hint_value), thunk->hints_valid);
1132         }
1133
1134         return r;
1135 }
1136
1137 static int __load_mappings(struct dm_cache_metadata *cmd,
1138                            struct dm_cache_policy *policy,
1139                            load_mapping_fn fn, void *context)
1140 {
1141         struct thunk thunk;
1142
1143         thunk.fn = fn;
1144         thunk.context = context;
1145
1146         thunk.cmd = cmd;
1147         thunk.respect_dirty_flags = cmd->clean_when_opened;
1148         thunk.hints_valid = hints_array_available(cmd, policy);
1149
1150         return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);
1151 }
1152
1153 int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1154                            struct dm_cache_policy *policy,
1155                            load_mapping_fn fn, void *context)
1156 {
1157         int r;
1158
1159         down_read(&cmd->root_lock);
1160         r = __load_mappings(cmd, policy, fn, context);
1161         up_read(&cmd->root_lock);
1162
1163         return r;
1164 }
1165
1166 static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1167 {
1168         int r = 0;
1169         __le64 value;
1170         dm_oblock_t oblock;
1171         unsigned flags;
1172
1173         memcpy(&value, leaf, sizeof(value));
1174         unpack_value(value, &oblock, &flags);
1175
1176         return r;
1177 }
1178
1179 static int __dump_mappings(struct dm_cache_metadata *cmd)
1180 {
1181         return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1182 }
1183
1184 void dm_cache_dump(struct dm_cache_metadata *cmd)
1185 {
1186         down_read(&cmd->root_lock);
1187         __dump_mappings(cmd);
1188         up_read(&cmd->root_lock);
1189 }
1190
1191 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1192 {
1193         int r;
1194
1195         down_read(&cmd->root_lock);
1196         r = cmd->changed;
1197         up_read(&cmd->root_lock);
1198
1199         return r;
1200 }
1201
1202 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1203 {
1204         int r;
1205         unsigned flags;
1206         dm_oblock_t oblock;
1207         __le64 value;
1208
1209         r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1210         if (r)
1211                 return r;
1212
1213         unpack_value(value, &oblock, &flags);
1214
1215         if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1216                 /* nothing to be done */
1217                 return 0;
1218
1219         value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1220         __dm_bless_for_disk(&value);
1221
1222         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1223                                &value, &cmd->root);
1224         if (r)
1225                 return r;
1226
1227         cmd->changed = true;
1228         return 0;
1229
1230 }
1231
1232 int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
1233                        dm_cblock_t cblock, bool dirty)
1234 {
1235         int r;
1236
1237         down_write(&cmd->root_lock);
1238         r = __dirty(cmd, cblock, dirty);
1239         up_write(&cmd->root_lock);
1240
1241         return r;
1242 }
1243
1244 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1245                                  struct dm_cache_statistics *stats)
1246 {
1247         down_read(&cmd->root_lock);
1248         *stats = cmd->stats;
1249         up_read(&cmd->root_lock);
1250 }
1251
1252 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1253                                  struct dm_cache_statistics *stats)
1254 {
1255         down_write(&cmd->root_lock);
1256         cmd->stats = *stats;
1257         up_write(&cmd->root_lock);
1258 }
1259
1260 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1261 {
1262         int r;
1263         flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1264                                  clear_clean_shutdown);
1265
1266         down_write(&cmd->root_lock);
1267         r = __commit_transaction(cmd, mutator);
1268         if (r)
1269                 goto out;
1270
1271         r = __begin_transaction(cmd);
1272
1273 out:
1274         up_write(&cmd->root_lock);
1275         return r;
1276 }
1277
1278 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1279                                            dm_block_t *result)
1280 {
1281         int r = -EINVAL;
1282
1283         down_read(&cmd->root_lock);
1284         r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1285         up_read(&cmd->root_lock);
1286
1287         return r;
1288 }
1289
1290 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1291                                    dm_block_t *result)
1292 {
1293         int r = -EINVAL;
1294
1295         down_read(&cmd->root_lock);
1296         r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1297         up_read(&cmd->root_lock);
1298
1299         return r;
1300 }
1301
1302 /*----------------------------------------------------------------*/
1303
1304 static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1305 {
1306         int r;
1307         __le32 value;
1308         size_t hint_size;
1309         const char *policy_name = dm_cache_policy_get_name(policy);
1310         const unsigned *policy_version = dm_cache_policy_get_version(policy);
1311
1312         if (!policy_name[0] ||
1313             (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1314                 return -EINVAL;
1315
1316         if (!policy_unchanged(cmd, policy)) {
1317                 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1318                 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1319
1320                 hint_size = dm_cache_policy_get_hint_size(policy);
1321                 if (!hint_size)
1322                         return 0; /* short-circuit hints initialization */
1323                 cmd->policy_hint_size = hint_size;
1324
1325                 if (cmd->hint_root) {
1326                         r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1327                         if (r)
1328                                 return r;
1329                 }
1330
1331                 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root);
1332                 if (r)
1333                         return r;
1334
1335                 value = cpu_to_le32(0);
1336                 __dm_bless_for_disk(&value);
1337                 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0,
1338                                     from_cblock(cmd->cache_blocks),
1339                                     &value, &cmd->hint_root);
1340                 if (r)
1341                         return r;
1342         }
1343
1344         return 0;
1345 }
1346
1347 static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, uint32_t hint)
1348 {
1349         struct dm_cache_metadata *cmd = context;
1350         __le32 value = cpu_to_le32(hint);
1351         int r;
1352
1353         __dm_bless_for_disk(&value);
1354
1355         r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
1356                                from_cblock(cblock), &value, &cmd->hint_root);
1357         cmd->changed = true;
1358
1359         return r;
1360 }
1361
1362 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1363 {
1364         int r;
1365
1366         r = begin_hints(cmd, policy);
1367         if (r) {
1368                 DMERR("begin_hints failed");
1369                 return r;
1370         }
1371
1372         return policy_walk_mappings(policy, save_hint, cmd);
1373 }
1374
1375 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1376 {
1377         int r;
1378
1379         down_write(&cmd->root_lock);
1380         r = write_hints(cmd, policy);
1381         up_write(&cmd->root_lock);
1382
1383         return r;
1384 }
1385
1386 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1387 {
1388         return blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1389 }