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 2
  29
  30 /*
  31  *  3 for btree insert +
  32  *  2 for btree lookup used within space map
  33  */
  34 #define CACHE_MAX_CONCURRENT_LOCKS 5
  35 #define SPACE_MAP_ROOT_SIZE 128
  36
  37 enum superblock_flag_bits {
  38         /* for spotting crashes that would invalidate the dirty bitset */
  39         CLEAN_SHUTDOWN,
  40         /* metadata must be checked using the tools */
  41         NEEDS_CHECK,
  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          * This flag is only used by metadata format 1.
  57          */
  58         M_DIRTY = 2
  59 };
  60
  61 struct cache_disk_superblock {
  62         __le32 csum;
  63         __le32 flags;
  64         __le64 blocknr;
  65
  66         __u8 uuid[16];
  67         __le64 magic;
  68         __le32 version;
  69
  70         __u8 policy_name[CACHE_POLICY_NAME_SIZE];
  71         __le32 policy_hint_size;
  72
  73         __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
  74         __le64 mapping_root;
  75         __le64 hint_root;
  76
  77         __le64 discard_root;
  78         __le64 discard_block_size;
  79         __le64 discard_nr_blocks;
  80
  81         __le32 data_block_size;
  82         __le32 metadata_block_size;
  83         __le32 cache_blocks;
  84
  85         __le32 compat_flags;
  86         __le32 compat_ro_flags;
  87         __le32 incompat_flags;
  88
  89         __le32 read_hits;
  90         __le32 read_misses;
  91         __le32 write_hits;
  92         __le32 write_misses;
  93
  94         __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
  95
  96         /*
  97          * Metadata format 2 fields.
  98          */
  99         __le64 dirty_root;
 100 } __packed;
 101
 102 struct dm_cache_metadata {
 103         atomic_t ref_count;
 104         struct list_head list;
 105
 106         unsigned version;
 107         struct block_device *bdev;
 108         struct dm_block_manager *bm;
 109         struct dm_space_map *metadata_sm;
 110         struct dm_transaction_manager *tm;
 111
 112         struct dm_array_info info;
 113         struct dm_array_info hint_info;
 114         struct dm_disk_bitset discard_info;
 115
 116         struct rw_semaphore root_lock;
 117         unsigned long flags;
 118         dm_block_t root;
 119         dm_block_t hint_root;
 120         dm_block_t discard_root;
 121
 122         sector_t discard_block_size;
 123         dm_dblock_t discard_nr_blocks;
 124
 125         sector_t data_block_size;
 126         dm_cblock_t cache_blocks;
 127         bool changed:1;
 128         bool clean_when_opened:1;
 129
 130         char policy_name[CACHE_POLICY_NAME_SIZE];
 131         unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
 132         size_t policy_hint_size;
 133         struct dm_cache_statistics stats;
 134
 135         /*
 136          * Reading the space map root can fail, so we read it into this
 137          * buffer before the superblock is locked and updated.
 138          */
 139         __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
 140
 141         /*
 142          * Set if a transaction has to be aborted but the attempt to roll
 143          * back to the previous (good) transaction failed.  The only
 144          * metadata operation permissible in this state is the closing of
 145          * the device.
 146          */
 147         bool fail_io:1;
 148
 149         /*
 150          * Metadata format 2 fields.
 151          */
 152         dm_block_t dirty_root;
 153         struct dm_disk_bitset dirty_info;
 154
 155         /*
 156          * These structures are used when loading metadata.  They're too
 157          * big to put on the stack.
 158          */
 159         struct dm_array_cursor mapping_cursor;
 160         struct dm_array_cursor hint_cursor;
 161         struct dm_bitset_cursor dirty_cursor;
 162 };
 163
 164 /*-------------------------------------------------------------------
 165  * superblock validator
 166  *-----------------------------------------------------------------*/
 167
 168 #define SUPERBLOCK_CSUM_XOR 9031977
 169
 170 static void sb_prepare_for_write(struct dm_block_validator *v,
 171                                  struct dm_block *b,
 172                                  size_t sb_block_size)
 173 {
 174         struct cache_disk_superblock *disk_super = dm_block_data(b);
 175
 176         disk_super->blocknr = cpu_to_le64(dm_block_location(b));
 177         disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 178                                                       sb_block_size - sizeof(__le32),
 179                                                       SUPERBLOCK_CSUM_XOR));
 180 }
 181
 182 static int check_metadata_version(struct cache_disk_superblock *disk_super)
 183 {
 184         uint32_t metadata_version = le32_to_cpu(disk_super->version);
 185
 186         if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
 187                 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
 188                       metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
 189                 return -EINVAL;
 190         }
 191
 192         return 0;
 193 }
 194
 195 static int sb_check(struct dm_block_validator *v,
 196                     struct dm_block *b,
 197                     size_t sb_block_size)
 198 {
 199         struct cache_disk_superblock *disk_super = dm_block_data(b);
 200         __le32 csum_le;
 201
 202         if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
 203                 DMERR("sb_check failed: blocknr %llu: wanted %llu",
 204                       le64_to_cpu(disk_super->blocknr),
 205                       (unsigned long long)dm_block_location(b));
 206                 return -ENOTBLK;
 207         }
 208
 209         if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
 210                 DMERR("sb_check failed: magic %llu: wanted %llu",
 211                       le64_to_cpu(disk_super->magic),
 212                       (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
 213                 return -EILSEQ;
 214         }
 215
 216         csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 217                                              sb_block_size - sizeof(__le32),
 218                                              SUPERBLOCK_CSUM_XOR));
 219         if (csum_le != disk_super->csum) {
 220                 DMERR("sb_check failed: csum %u: wanted %u",
 221                       le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
 222                 return -EILSEQ;
 223         }
 224
 225         return check_metadata_version(disk_super);
 226 }
 227
 228 static struct dm_block_validator sb_validator = {
 229         .name = "superblock",
 230         .prepare_for_write = sb_prepare_for_write,
 231         .check = sb_check
 232 };
 233
 234 /*----------------------------------------------------------------*/
 235
 236 static int superblock_read_lock(struct dm_cache_metadata *cmd,
 237                                 struct dm_block **sblock)
 238 {
 239         return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 240                                &sb_validator, sblock);
 241 }
 242
 243 static int superblock_lock_zero(struct dm_cache_metadata *cmd,
 244                                 struct dm_block **sblock)
 245 {
 246         return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 247                                      &sb_validator, sblock);
 248 }
 249
 250 static int superblock_lock(struct dm_cache_metadata *cmd,
 251                            struct dm_block **sblock)
 252 {
 253         return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 254                                 &sb_validator, sblock);
 255 }
 256
 257 /*----------------------------------------------------------------*/
 258
 259 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
 260 {
 261         int r;
 262         unsigned i;
 263         struct dm_block *b;
 264         __le64 *data_le, zero = cpu_to_le64(0);
 265         unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
 266
 267         /*
 268          * We can't use a validator here - it may be all zeroes.
 269          */
 270         r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
 271         if (r)
 272                 return r;
 273
 274         data_le = dm_block_data(b);
 275         *result = true;
 276         for (i = 0; i < sb_block_size; i++) {
 277                 if (data_le[i] != zero) {
 278                         *result = false;
 279                         break;
 280                 }
 281         }
 282
 283         dm_bm_unlock(b);
 284
 285         return 0;
 286 }
 287
 288 static void __setup_mapping_info(struct dm_cache_metadata *cmd)
 289 {
 290         struct dm_btree_value_type vt;
 291
 292         vt.context = NULL;
 293         vt.size = sizeof(__le64);
 294         vt.inc = NULL;
 295         vt.dec = NULL;
 296         vt.equal = NULL;
 297         dm_array_info_init(&cmd->info, cmd->tm, &vt);
 298
 299         if (cmd->policy_hint_size) {
 300                 vt.size = sizeof(__le32);
 301                 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
 302         }
 303 }
 304
 305 static int __save_sm_root(struct dm_cache_metadata *cmd)
 306 {
 307         int r;
 308         size_t metadata_len;
 309
 310         r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
 311         if (r < 0)
 312                 return r;
 313
 314         return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
 315                                metadata_len);
 316 }
 317
 318 static void __copy_sm_root(struct dm_cache_metadata *cmd,
 319                            struct cache_disk_superblock *disk_super)
 320 {
 321         memcpy(&disk_super->metadata_space_map_root,
 322                &cmd->metadata_space_map_root,
 323                sizeof(cmd->metadata_space_map_root));
 324 }
 325
 326 static bool separate_dirty_bits(struct dm_cache_metadata *cmd)
 327 {
 328         return cmd->version >= 2;
 329 }
 330
 331 static int __write_initial_superblock(struct dm_cache_metadata *cmd)
 332 {
 333         int r;
 334         struct dm_block *sblock;
 335         struct cache_disk_superblock *disk_super;
 336         sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
 337
 338         /* FIXME: see if we can lose the max sectors limit */
 339         if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
 340                 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
 341
 342         r = dm_tm_pre_commit(cmd->tm);
 343         if (r < 0)
 344                 return r;
 345
 346         /*
 347          * dm_sm_copy_root() can fail.  So we need to do it before we start
 348          * updating the superblock.
 349          */
 350         r = __save_sm_root(cmd);
 351         if (r)
 352                 return r;
 353
 354         r = superblock_lock_zero(cmd, &sblock);
 355         if (r)
 356                 return r;
 357
 358         disk_super = dm_block_data(sblock);
 359         disk_super->flags = 0;
 360         memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
 361         disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
 362         disk_super->version = cpu_to_le32(cmd->version);
 363         memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
 364         memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
 365         disk_super->policy_hint_size = 0;
 366
 367         __copy_sm_root(cmd, disk_super);
 368
 369         disk_super->mapping_root = cpu_to_le64(cmd->root);
 370         disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 371         disk_super->discard_root = cpu_to_le64(cmd->discard_root);
 372         disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
 373         disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
 374         disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
 375         disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
 376         disk_super->cache_blocks = cpu_to_le32(0);
 377
 378         disk_super->read_hits = cpu_to_le32(0);
 379         disk_super->read_misses = cpu_to_le32(0);
 380         disk_super->write_hits = cpu_to_le32(0);
 381         disk_super->write_misses = cpu_to_le32(0);
 382
 383         if (separate_dirty_bits(cmd))
 384                 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
 385
 386         return dm_tm_commit(cmd->tm, sblock);
 387 }
 388
 389 static int __format_metadata(struct dm_cache_metadata *cmd)
 390 {
 391         int r;
 392
 393         r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 394                                  &cmd->tm, &cmd->metadata_sm);
 395         if (r < 0) {
 396                 DMERR("tm_create_with_sm failed");
 397                 return r;
 398         }
 399
 400         __setup_mapping_info(cmd);
 401
 402         r = dm_array_empty(&cmd->info, &cmd->root);
 403         if (r < 0)
 404                 goto bad;
 405
 406         if (separate_dirty_bits(cmd)) {
 407                 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
 408                 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root);
 409                 if (r < 0)
 410                         goto bad;
 411         }
 412
 413         dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
 414         r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
 415         if (r < 0)
 416                 goto bad;
 417
 418         cmd->discard_block_size = 0;
 419         cmd->discard_nr_blocks = 0;
 420
 421         r = __write_initial_superblock(cmd);
 422         if (r)
 423                 goto bad;
 424
 425         cmd->clean_when_opened = true;
 426         return 0;
 427
 428 bad:
 429         dm_tm_destroy(cmd->tm);
 430         dm_sm_destroy(cmd->metadata_sm);
 431
 432         return r;
 433 }
 434
 435 static int __check_incompat_features(struct cache_disk_superblock *disk_super,
 436                                      struct dm_cache_metadata *cmd)
 437 {
 438         uint32_t incompat_flags, features;
 439
 440         incompat_flags = le32_to_cpu(disk_super->incompat_flags);
 441         features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
 442         if (features) {
 443                 DMERR("could not access metadata due to unsupported optional features (%lx).",
 444                       (unsigned long)features);
 445                 return -EINVAL;
 446         }
 447
 448         /*
 449          * Check for read-only metadata to skip the following RDWR checks.
 450          */
 451         if (get_disk_ro(cmd->bdev->bd_disk))
 452                 return 0;
 453
 454         features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
 455         if (features) {
 456                 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
 457                       (unsigned long)features);
 458                 return -EINVAL;
 459         }
 460
 461         return 0;
 462 }
 463
 464 static int __open_metadata(struct dm_cache_metadata *cmd)
 465 {
 466         int r;
 467         struct dm_block *sblock;
 468         struct cache_disk_superblock *disk_super;
 469         unsigned long sb_flags;
 470
 471         r = superblock_read_lock(cmd, &sblock);
 472         if (r < 0) {
 473                 DMERR("couldn't read lock superblock");
 474                 return r;
 475         }
 476
 477         disk_super = dm_block_data(sblock);
 478
 479         /* Verify the data block size hasn't changed */
 480         if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
 481                 DMERR("changing the data block size (from %u to %llu) is not supported",
 482                       le32_to_cpu(disk_super->data_block_size),
 483                       (unsigned long long)cmd->data_block_size);
 484                 r = -EINVAL;
 485                 goto bad;
 486         }
 487
 488         r = __check_incompat_features(disk_super, cmd);
 489         if (r < 0)
 490                 goto bad;
 491
 492         r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 493                                disk_super->metadata_space_map_root,
 494                                sizeof(disk_super->metadata_space_map_root),
 495                                &cmd->tm, &cmd->metadata_sm);
 496         if (r < 0) {
 497                 DMERR("tm_open_with_sm failed");
 498                 goto bad;
 499         }
 500
 501         __setup_mapping_info(cmd);
 502         dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
 503         dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
 504         sb_flags = le32_to_cpu(disk_super->flags);
 505         cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
 506         dm_bm_unlock(sblock);
 507
 508         return 0;
 509
 510 bad:
 511         dm_bm_unlock(sblock);
 512         return r;
 513 }
 514
 515 static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
 516                                      bool format_device)
 517 {
 518         int r;
 519         bool unformatted = false;
 520
 521         r = __superblock_all_zeroes(cmd->bm, &unformatted);
 522         if (r)
 523                 return r;
 524
 525         if (unformatted)
 526                 return format_device ? __format_metadata(cmd) : -EPERM;
 527
 528         return __open_metadata(cmd);
 529 }
 530
 531 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
 532                                             bool may_format_device)
 533 {
 534         int r;
 535         cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
 536                                           CACHE_MAX_CONCURRENT_LOCKS);
 537         if (IS_ERR(cmd->bm)) {
 538                 DMERR("could not create block manager");
 539                 return PTR_ERR(cmd->bm);
 540         }
 541
 542         r = __open_or_format_metadata(cmd, may_format_device);
 543         if (r)
 544                 dm_block_manager_destroy(cmd->bm);
 545
 546         return r;
 547 }
 548
 549 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
 550 {
 551         dm_sm_destroy(cmd->metadata_sm);
 552         dm_tm_destroy(cmd->tm);
 553         dm_block_manager_destroy(cmd->bm);
 554 }
 555
 556 typedef unsigned long (*flags_mutator)(unsigned long);
 557
 558 static void update_flags(struct cache_disk_superblock *disk_super,
 559                          flags_mutator mutator)
 560 {
 561         uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
 562         disk_super->flags = cpu_to_le32(sb_flags);
 563 }
 564
 565 static unsigned long set_clean_shutdown(unsigned long flags)
 566 {
 567         set_bit(CLEAN_SHUTDOWN, &flags);
 568         return flags;
 569 }
 570
 571 static unsigned long clear_clean_shutdown(unsigned long flags)
 572 {
 573         clear_bit(CLEAN_SHUTDOWN, &flags);
 574         return flags;
 575 }
 576
 577 static void read_superblock_fields(struct dm_cache_metadata *cmd,
 578                                    struct cache_disk_superblock *disk_super)
 579 {
 580         cmd->version = le32_to_cpu(disk_super->version);
 581         cmd->flags = le32_to_cpu(disk_super->flags);
 582         cmd->root = le64_to_cpu(disk_super->mapping_root);
 583         cmd->hint_root = le64_to_cpu(disk_super->hint_root);
 584         cmd->discard_root = le64_to_cpu(disk_super->discard_root);
 585         cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
 586         cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
 587         cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
 588         cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
 589         strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
 590         cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
 591         cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
 592         cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
 593         cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
 594
 595         cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
 596         cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
 597         cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
 598         cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
 599
 600         if (separate_dirty_bits(cmd))
 601                 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
 602
 603         cmd->changed = false;
 604 }
 605
 606 /*
 607  * The mutator updates the superblock flags.
 608  */
 609 static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
 610                                      flags_mutator mutator)
 611 {
 612         int r;
 613         struct cache_disk_superblock *disk_super;
 614         struct dm_block *sblock;
 615
 616         r = superblock_lock(cmd, &sblock);
 617         if (r)
 618                 return r;
 619
 620         disk_super = dm_block_data(sblock);
 621         update_flags(disk_super, mutator);
 622         read_superblock_fields(cmd, disk_super);
 623         dm_bm_unlock(sblock);
 624
 625         return dm_bm_flush(cmd->bm);
 626 }
 627
 628 static int __begin_transaction(struct dm_cache_metadata *cmd)
 629 {
 630         int r;
 631         struct cache_disk_superblock *disk_super;
 632         struct dm_block *sblock;
 633
 634         /*
 635          * We re-read the superblock every time.  Shouldn't need to do this
 636          * really.
 637          */
 638         r = superblock_read_lock(cmd, &sblock);
 639         if (r)
 640                 return r;
 641
 642         disk_super = dm_block_data(sblock);
 643         read_superblock_fields(cmd, disk_super);
 644         dm_bm_unlock(sblock);
 645
 646         return 0;
 647 }
 648
 649 static int __commit_transaction(struct dm_cache_metadata *cmd,
 650                                 flags_mutator mutator)
 651 {
 652         int r;
 653         struct cache_disk_superblock *disk_super;
 654         struct dm_block *sblock;
 655
 656         /*
 657          * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
 658          */
 659         BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
 660
 661         if (separate_dirty_bits(cmd)) {
 662                 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
 663                                     &cmd->dirty_root);
 664                 if (r)
 665                         return r;
 666         }
 667
 668         r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
 669                             &cmd->discard_root);
 670         if (r)
 671                 return r;
 672
 673         r = dm_tm_pre_commit(cmd->tm);
 674         if (r < 0)
 675                 return r;
 676
 677         r = __save_sm_root(cmd);
 678         if (r)
 679                 return r;
 680
 681         r = superblock_lock(cmd, &sblock);
 682         if (r)
 683                 return r;
 684
 685         disk_super = dm_block_data(sblock);
 686
 687         disk_super->flags = cpu_to_le32(cmd->flags);
 688         if (mutator)
 689                 update_flags(disk_super, mutator);
 690
 691         disk_super->mapping_root = cpu_to_le64(cmd->root);
 692         if (separate_dirty_bits(cmd))
 693                 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
 694         disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 695         disk_super->discard_root = cpu_to_le64(cmd->discard_root);
 696         disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
 697         disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
 698         disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
 699         strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
 700         disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
 701         disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
 702         disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
 703
 704         disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
 705         disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
 706         disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
 707         disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
 708         __copy_sm_root(cmd, disk_super);
 709
 710         return dm_tm_commit(cmd->tm, sblock);
 711 }
 712
 713 /*----------------------------------------------------------------*/
 714
 715 /*
 716  * The mappings are held in a dm-array that has 64-bit values stored in
 717  * little-endian format.  The index is the cblock, the high 48bits of the
 718  * value are the oblock and the low 16 bit the flags.
 719  */
 720 #define FLAGS_MASK ((1 << 16) - 1)
 721
 722 static __le64 pack_value(dm_oblock_t block, unsigned flags)
 723 {
 724         uint64_t value = from_oblock(block);
 725         value <<= 16;
 726         value = value | (flags & FLAGS_MASK);
 727         return cpu_to_le64(value);
 728 }
 729
 730 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
 731 {
 732         uint64_t value = le64_to_cpu(value_le);
 733         uint64_t b = value >> 16;
 734         *block = to_oblock(b);
 735         *flags = value & FLAGS_MASK;
 736 }
 737
 738 /*----------------------------------------------------------------*/
 739
 740 static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
 741                                                sector_t data_block_size,
 742                                                bool may_format_device,
 743                                                size_t policy_hint_size,
 744                                                unsigned metadata_version)
 745 {
 746         int r;
 747         struct dm_cache_metadata *cmd;
 748
 749         cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
 750         if (!cmd) {
 751                 DMERR("could not allocate metadata struct");
 752                 return ERR_PTR(-ENOMEM);
 753         }
 754
 755         cmd->version = metadata_version;
 756         atomic_set(&cmd->ref_count, 1);
 757         init_rwsem(&cmd->root_lock);
 758         cmd->bdev = bdev;
 759         cmd->data_block_size = data_block_size;
 760         cmd->cache_blocks = 0;
 761         cmd->policy_hint_size = policy_hint_size;
 762         cmd->changed = true;
 763         cmd->fail_io = false;
 764
 765         r = __create_persistent_data_objects(cmd, may_format_device);
 766         if (r) {
 767                 kfree(cmd);
 768                 return ERR_PTR(r);
 769         }
 770
 771         r = __begin_transaction_flags(cmd, clear_clean_shutdown);
 772         if (r < 0) {
 773                 dm_cache_metadata_close(cmd);
 774                 return ERR_PTR(r);
 775         }
 776
 777         return cmd;
 778 }
 779
 780 /*
 781  * We keep a little list of ref counted metadata objects to prevent two
 782  * different target instances creating separate bufio instances.  This is
 783  * an issue if a table is reloaded before the suspend.
 784  */
 785 static DEFINE_MUTEX(table_lock);
 786 static LIST_HEAD(table);
 787
 788 static struct dm_cache_metadata *lookup(struct block_device *bdev)
 789 {
 790         struct dm_cache_metadata *cmd;
 791
 792         list_for_each_entry(cmd, &table, list)
 793                 if (cmd->bdev == bdev) {
 794                         atomic_inc(&cmd->ref_count);
 795                         return cmd;
 796                 }
 797
 798         return NULL;
 799 }
 800
 801 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
 802                                                 sector_t data_block_size,
 803                                                 bool may_format_device,
 804                                                 size_t policy_hint_size,
 805                                                 unsigned metadata_version)
 806 {
 807         struct dm_cache_metadata *cmd, *cmd2;
 808
 809         mutex_lock(&table_lock);
 810         cmd = lookup(bdev);
 811         mutex_unlock(&table_lock);
 812
 813         if (cmd)
 814                 return cmd;
 815
 816         cmd = metadata_open(bdev, data_block_size, may_format_device,
 817                             policy_hint_size, metadata_version);
 818         if (!IS_ERR(cmd)) {
 819                 mutex_lock(&table_lock);
 820                 cmd2 = lookup(bdev);
 821                 if (cmd2) {
 822                         mutex_unlock(&table_lock);
 823                         __destroy_persistent_data_objects(cmd);
 824                         kfree(cmd);
 825                         return cmd2;
 826                 }
 827                 list_add(&cmd->list, &table);
 828                 mutex_unlock(&table_lock);
 829         }
 830
 831         return cmd;
 832 }
 833
 834 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
 835 {
 836         if (cmd->data_block_size != data_block_size) {
 837                 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
 838                       (unsigned long long) data_block_size,
 839                       (unsigned long long) cmd->data_block_size);
 840                 return false;
 841         }
 842
 843         return true;
 844 }
 845
 846 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
 847                                                  sector_t data_block_size,
 848                                                  bool may_format_device,
 849                                                  size_t policy_hint_size,
 850                                                  unsigned metadata_version)
 851 {
 852         struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
 853                                                        policy_hint_size, metadata_version);
 854
 855         if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
 856                 dm_cache_metadata_close(cmd);
 857                 return ERR_PTR(-EINVAL);
 858         }
 859
 860         return cmd;
 861 }
 862
 863 void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
 864 {
 865         if (atomic_dec_and_test(&cmd->ref_count)) {
 866                 mutex_lock(&table_lock);
 867                 list_del(&cmd->list);
 868                 mutex_unlock(&table_lock);
 869
 870                 if (!cmd->fail_io)
 871                         __destroy_persistent_data_objects(cmd);
 872                 kfree(cmd);
 873         }
 874 }
 875
 876 /*
 877  * Checks that the given cache block is either unmapped or clean.
 878  */
 879 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
 880                                       bool *result)
 881 {
 882         int r;
 883         __le64 value;
 884         dm_oblock_t ob;
 885         unsigned flags;
 886
 887         r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
 888         if (r)
 889                 return r;
 890
 891         unpack_value(value, &ob, &flags);
 892         *result = !((flags & M_VALID) && (flags & M_DIRTY));
 893
 894         return 0;
 895 }
 896
 897 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
 898                                            dm_cblock_t begin, dm_cblock_t end,
 899                                            bool *result)
 900 {
 901         int r;
 902         *result = true;
 903
 904         while (begin != end) {
 905                 r = block_clean_combined_dirty(cmd, begin, result);
 906                 if (r) {
 907                         DMERR("block_clean_combined_dirty failed");
 908                         return r;
 909                 }
 910
 911                 if (!*result) {
 912                         DMERR("cache block %llu is dirty",
 913                               (unsigned long long) from_cblock(begin));
 914                         return 0;
 915                 }
 916
 917                 begin = to_cblock(from_cblock(begin) + 1);
 918         }
 919
 920         return 0;
 921 }
 922
 923 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
 924                                            dm_cblock_t begin, dm_cblock_t end,
 925                                            bool *result)
 926 {
 927         int r;
 928         bool dirty_flag;
 929         *result = true;
 930
 931         r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
 932                                    from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
 933         if (r) {
 934                 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__);
 935                 return r;
 936         }
 937
 938         r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin));
 939         if (r) {
 940                 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
 941                 dm_bitset_cursor_end(&cmd->dirty_cursor);
 942                 return r;
 943         }
 944
 945         while (begin != end) {
 946                 /*
 947                  * We assume that unmapped blocks have their dirty bit
 948                  * cleared.
 949                  */
 950                 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor);
 951                 if (dirty_flag) {
 952                         DMERR("%s: cache block %llu is dirty", __func__,
 953                               (unsigned long long) from_cblock(begin));
 954                         dm_bitset_cursor_end(&cmd->dirty_cursor);
 955                         *result = false;
 956                         return 0;
 957                 }
 958
 959                 begin = to_cblock(from_cblock(begin) + 1);
 960                 if (begin == end)
 961                         break;
 962
 963                 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
 964                 if (r) {
 965                         DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
 966                         dm_bitset_cursor_end(&cmd->dirty_cursor);
 967                         return r;
 968                 }
 969         }
 970
 971         dm_bitset_cursor_end(&cmd->dirty_cursor);
 972
 973         return 0;
 974 }
 975
 976 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
 977                                         dm_cblock_t begin, dm_cblock_t end,
 978                                         bool *result)
 979 {
 980         if (separate_dirty_bits(cmd))
 981                 return blocks_are_clean_separate_dirty(cmd, begin, end, result);
 982         else
 983                 return blocks_are_clean_combined_dirty(cmd, begin, end, result);
 984 }
 985
 986 static bool cmd_write_lock(struct dm_cache_metadata *cmd)
 987 {
 988         down_write(&cmd->root_lock);
 989         if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
 990                 up_write(&cmd->root_lock);
 991                 return false;
 992         }
 993         return true;
 994 }
 995
 996 #define WRITE_LOCK(cmd)                         \
 997         do {                                    \
 998                 if (!cmd_write_lock((cmd)))     \
 999                         return -EINVAL;         \
1000         } while(0)
1001
1002 #define WRITE_LOCK_VOID(cmd)                    \
1003         do {                                    \
1004                 if (!cmd_write_lock((cmd)))     \
1005                         return;                 \
1006         } while(0)
1007
1008 #define WRITE_UNLOCK(cmd) \
1009         up_write(&(cmd)->root_lock)
1010
1011 static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1012 {
1013         down_read(&cmd->root_lock);
1014         if (cmd->fail_io) {
1015                 up_read(&cmd->root_lock);
1016                 return false;
1017         }
1018         return true;
1019 }
1020
1021 #define READ_LOCK(cmd)                          \
1022         do {                                    \
1023                 if (!cmd_read_lock((cmd)))      \
1024                         return -EINVAL;         \
1025         } while(0)
1026
1027 #define READ_LOCK_VOID(cmd)                     \
1028         do {                                    \
1029                 if (!cmd_read_lock((cmd)))      \
1030                         return;                 \
1031         } while(0)
1032
1033 #define READ_UNLOCK(cmd) \
1034         up_read(&(cmd)->root_lock)
1035
1036 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1037 {
1038         int r;
1039         bool clean;
1040         __le64 null_mapping = pack_value(0, 0);
1041
1042         WRITE_LOCK(cmd);
1043         __dm_bless_for_disk(&null_mapping);
1044
1045         if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1046                 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
1047                 if (r) {
1048                         __dm_unbless_for_disk(&null_mapping);
1049                         goto out;
1050                 }
1051
1052                 if (!clean) {
1053                         DMERR("unable to shrink cache due to dirty blocks");
1054                         r = -EINVAL;
1055                         __dm_unbless_for_disk(&null_mapping);
1056                         goto out;
1057                 }
1058         }
1059
1060         r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1061                             from_cblock(new_cache_size),
1062                             &null_mapping, &cmd->root);
1063         if (r)
1064                 goto out;
1065
1066         if (separate_dirty_bits(cmd)) {
1067                 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1068                                      from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1069                                      false, &cmd->dirty_root);
1070                 if (r)
1071                         goto out;
1072         }
1073
1074         cmd->cache_blocks = new_cache_size;
1075         cmd->changed = true;
1076
1077 out:
1078         WRITE_UNLOCK(cmd);
1079
1080         return r;
1081 }
1082
1083 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1084                                    sector_t discard_block_size,
1085                                    dm_dblock_t new_nr_entries)
1086 {
1087         int r;
1088
1089         WRITE_LOCK(cmd);
1090         r = dm_bitset_resize(&cmd->discard_info,
1091                              cmd->discard_root,
1092                              from_dblock(cmd->discard_nr_blocks),
1093                              from_dblock(new_nr_entries),
1094                              false, &cmd->discard_root);
1095         if (!r) {
1096                 cmd->discard_block_size = discard_block_size;
1097                 cmd->discard_nr_blocks = new_nr_entries;
1098         }
1099
1100         cmd->changed = true;
1101         WRITE_UNLOCK(cmd);
1102
1103         return r;
1104 }
1105
1106 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1107 {
1108         return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
1109                                  from_dblock(b), &cmd->discard_root);
1110 }
1111
1112 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1113 {
1114         return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
1115                                    from_dblock(b), &cmd->discard_root);
1116 }
1117
1118 static int __discard(struct dm_cache_metadata *cmd,
1119                      dm_dblock_t dblock, bool discard)
1120 {
1121         int r;
1122
1123         r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1124         if (r)
1125                 return r;
1126
1127         cmd->changed = true;
1128         return 0;
1129 }
1130
1131 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1132                          dm_dblock_t dblock, bool discard)
1133 {
1134         int r;
1135
1136         WRITE_LOCK(cmd);
1137         r = __discard(cmd, dblock, discard);
1138         WRITE_UNLOCK(cmd);
1139
1140         return r;
1141 }
1142
1143 static int __load_discards(struct dm_cache_metadata *cmd,
1144                            load_discard_fn fn, void *context)
1145 {
1146         int r = 0;
1147         uint32_t b;
1148         struct dm_bitset_cursor c;
1149
1150         if (from_dblock(cmd->discard_nr_blocks) == 0)
1151                 /* nothing to do */
1152                 return 0;
1153
1154         if (cmd->clean_when_opened) {
1155                 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1156                 if (r)
1157                         return r;
1158
1159                 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1160                                            from_dblock(cmd->discard_nr_blocks), &c);
1161                 if (r)
1162                         return r;
1163
1164                 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1165                         r = fn(context, cmd->discard_block_size, to_dblock(b),
1166                                dm_bitset_cursor_get_value(&c));
1167                         if (r)
1168                                 break;
1169                 }
1170
1171                 dm_bitset_cursor_end(&c);
1172
1173         } else {
1174                 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1175                         r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1176                         if (r)
1177                                 return r;
1178                 }
1179         }
1180
1181         return r;
1182 }
1183
1184 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1185                            load_discard_fn fn, void *context)
1186 {
1187         int r;
1188
1189         READ_LOCK(cmd);
1190         r = __load_discards(cmd, fn, context);
1191         READ_UNLOCK(cmd);
1192
1193         return r;
1194 }
1195
1196 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1197 {
1198         READ_LOCK(cmd);
1199         *result = cmd->cache_blocks;
1200         READ_UNLOCK(cmd);
1201
1202         return 0;
1203 }
1204
1205 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1206 {
1207         int r;
1208         __le64 value = pack_value(0, 0);
1209
1210         __dm_bless_for_disk(&value);
1211         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1212                                &value, &cmd->root);
1213         if (r)
1214                 return r;
1215
1216         cmd->changed = true;
1217         return 0;
1218 }
1219
1220 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1221 {
1222         int r;
1223
1224         WRITE_LOCK(cmd);
1225         r = __remove(cmd, cblock);
1226         WRITE_UNLOCK(cmd);
1227
1228         return r;
1229 }
1230
1231 static int __insert(struct dm_cache_metadata *cmd,
1232                     dm_cblock_t cblock, dm_oblock_t oblock)
1233 {
1234         int r;
1235         __le64 value = pack_value(oblock, M_VALID);
1236         __dm_bless_for_disk(&value);
1237
1238         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1239                                &value, &cmd->root);
1240         if (r)
1241                 return r;
1242
1243         cmd->changed = true;
1244         return 0;
1245 }
1246
1247 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1248                             dm_cblock_t cblock, dm_oblock_t oblock)
1249 {
1250         int r;
1251
1252         WRITE_LOCK(cmd);
1253         r = __insert(cmd, cblock, oblock);
1254         WRITE_UNLOCK(cmd);
1255
1256         return r;
1257 }
1258
1259 struct thunk {
1260         load_mapping_fn fn;
1261         void *context;
1262
1263         struct dm_cache_metadata *cmd;
1264         bool respect_dirty_flags;
1265         bool hints_valid;
1266 };
1267
1268 static bool policy_unchanged(struct dm_cache_metadata *cmd,
1269                              struct dm_cache_policy *policy)
1270 {
1271         const char *policy_name = dm_cache_policy_get_name(policy);
1272         const unsigned *policy_version = dm_cache_policy_get_version(policy);
1273         size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1274
1275         /*
1276          * Ensure policy names match.
1277          */
1278         if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1279                 return false;
1280
1281         /*
1282          * Ensure policy major versions match.
1283          */
1284         if (cmd->policy_version[0] != policy_version[0])
1285                 return false;
1286
1287         /*
1288          * Ensure policy hint sizes match.
1289          */
1290         if (cmd->policy_hint_size != policy_hint_size)
1291                 return false;
1292
1293         return true;
1294 }
1295
1296 static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1297 {
1298         return cmd->hint_root && cmd->policy_hint_size;
1299 }
1300
1301 static bool hints_array_available(struct dm_cache_metadata *cmd,
1302                                   struct dm_cache_policy *policy)
1303 {
1304         return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1305                 hints_array_initialized(cmd);
1306 }
1307
1308 static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1309                              uint64_t cb, bool hints_valid,
1310                              struct dm_array_cursor *mapping_cursor,
1311                              struct dm_array_cursor *hint_cursor,
1312                              load_mapping_fn fn, void *context)
1313 {
1314         int r = 0;
1315
1316         __le64 mapping;
1317         __le32 hint = 0;
1318
1319         __le64 *mapping_value_le;
1320         __le32 *hint_value_le;
1321
1322         dm_oblock_t oblock;
1323         unsigned flags;
1324
1325         dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1326         memcpy(&mapping, mapping_value_le, sizeof(mapping));
1327         unpack_value(mapping, &oblock, &flags);
1328
1329         if (flags & M_VALID) {
1330                 if (hints_valid) {
1331                         dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1332                         memcpy(&hint, hint_value_le, sizeof(hint));
1333                 }
1334
1335                 r = fn(context, oblock, to_cblock(cb), flags & M_DIRTY,
1336                        le32_to_cpu(hint), hints_valid);
1337                 if (r) {
1338                         DMERR("policy couldn't load cache block %llu",
1339                               (unsigned long long) from_cblock(to_cblock(cb)));
1340                 }
1341         }
1342
1343         return r;
1344 }
1345
1346 static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1347                              uint64_t cb, bool hints_valid,
1348                              struct dm_array_cursor *mapping_cursor,
1349                              struct dm_array_cursor *hint_cursor,
1350                              struct dm_bitset_cursor *dirty_cursor,
1351                              load_mapping_fn fn, void *context)
1352 {
1353         int r = 0;
1354
1355         __le64 mapping;
1356         __le32 hint = 0;
1357
1358         __le64 *mapping_value_le;
1359         __le32 *hint_value_le;
1360
1361         dm_oblock_t oblock;
1362         unsigned flags;
1363         bool dirty;
1364
1365         dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1366         memcpy(&mapping, mapping_value_le, sizeof(mapping));
1367         unpack_value(mapping, &oblock, &flags);
1368
1369         if (flags & M_VALID) {
1370                 if (hints_valid) {
1371                         dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1372                         memcpy(&hint, hint_value_le, sizeof(hint));
1373                 }
1374
1375                 dirty = dm_bitset_cursor_get_value(dirty_cursor);
1376                 r = fn(context, oblock, to_cblock(cb), dirty,
1377                        le32_to_cpu(hint), hints_valid);
1378                 if (r) {
1379                         DMERR("policy couldn't load cache block %llu",
1380                               (unsigned long long) from_cblock(to_cblock(cb)));
1381                 }
1382         }
1383
1384         return r;
1385 }
1386
1387 static int __load_mappings(struct dm_cache_metadata *cmd,
1388                            struct dm_cache_policy *policy,
1389                            load_mapping_fn fn, void *context)
1390 {
1391         int r;
1392         uint64_t cb;
1393
1394         bool hints_valid = hints_array_available(cmd, policy);
1395
1396         if (from_cblock(cmd->cache_blocks) == 0)
1397                 /* Nothing to do */
1398                 return 0;
1399
1400         r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1401         if (r)
1402                 return r;
1403
1404         if (hints_valid) {
1405                 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1406                 if (r) {
1407                         dm_array_cursor_end(&cmd->mapping_cursor);
1408                         return r;
1409                 }
1410         }
1411
1412         if (separate_dirty_bits(cmd)) {
1413                 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1414                                            from_cblock(cmd->cache_blocks),
1415                                            &cmd->dirty_cursor);
1416                 if (r) {
1417                         dm_array_cursor_end(&cmd->hint_cursor);
1418                         dm_array_cursor_end(&cmd->mapping_cursor);
1419                         return r;
1420                 }
1421         }
1422
1423         for (cb = 0; ; cb++) {
1424                 if (separate_dirty_bits(cmd))
1425                         r = __load_mapping_v2(cmd, cb, hints_valid,
1426                                               &cmd->mapping_cursor,
1427                                               &cmd->hint_cursor,
1428                                               &cmd->dirty_cursor,
1429                                               fn, context);
1430                 else
1431                         r = __load_mapping_v1(cmd, cb, hints_valid,
1432                                               &cmd->mapping_cursor, &cmd->hint_cursor,
1433                                               fn, context);
1434                 if (r)
1435                         goto out;
1436
1437                 /*
1438                  * We need to break out before we move the cursors.
1439                  */
1440                 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1441                         break;
1442
1443                 r = dm_array_cursor_next(&cmd->mapping_cursor);
1444                 if (r) {
1445                         DMERR("dm_array_cursor_next for mapping failed");
1446                         goto out;
1447                 }
1448
1449                 if (hints_valid) {
1450                         r = dm_array_cursor_next(&cmd->hint_cursor);
1451                         if (r) {
1452                                 DMERR("dm_array_cursor_next for hint failed");
1453                                 goto out;
1454                         }
1455                 }
1456
1457                 if (separate_dirty_bits(cmd)) {
1458                         r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1459                         if (r) {
1460                                 DMERR("dm_bitset_cursor_next for dirty failed");
1461                                 goto out;
1462                         }
1463                 }
1464         }
1465 out:
1466         dm_array_cursor_end(&cmd->mapping_cursor);
1467         if (hints_valid)
1468                 dm_array_cursor_end(&cmd->hint_cursor);
1469
1470         if (separate_dirty_bits(cmd))
1471                 dm_bitset_cursor_end(&cmd->dirty_cursor);
1472
1473         return r;
1474 }
1475
1476 int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1477                            struct dm_cache_policy *policy,
1478                            load_mapping_fn fn, void *context)
1479 {
1480         int r;
1481
1482         READ_LOCK(cmd);
1483         r = __load_mappings(cmd, policy, fn, context);
1484         READ_UNLOCK(cmd);
1485
1486         return r;
1487 }
1488
1489 static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1490 {
1491         int r = 0;
1492         __le64 value;
1493         dm_oblock_t oblock;
1494         unsigned flags;
1495
1496         memcpy(&value, leaf, sizeof(value));
1497         unpack_value(value, &oblock, &flags);
1498
1499         return r;
1500 }
1501
1502 static int __dump_mappings(struct dm_cache_metadata *cmd)
1503 {
1504         return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1505 }
1506
1507 void dm_cache_dump(struct dm_cache_metadata *cmd)
1508 {
1509         READ_LOCK_VOID(cmd);
1510         __dump_mappings(cmd);
1511         READ_UNLOCK(cmd);
1512 }
1513
1514 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1515 {
1516         int r;
1517
1518         READ_LOCK(cmd);
1519         r = cmd->changed;
1520         READ_UNLOCK(cmd);
1521
1522         return r;
1523 }
1524
1525 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1526 {
1527         int r;
1528         unsigned flags;
1529         dm_oblock_t oblock;
1530         __le64 value;
1531
1532         r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1533         if (r)
1534                 return r;
1535
1536         unpack_value(value, &oblock, &flags);
1537
1538         if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1539                 /* nothing to be done */
1540                 return 0;
1541
1542         value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1543         __dm_bless_for_disk(&value);
1544
1545         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1546                                &value, &cmd->root);
1547         if (r)
1548                 return r;
1549
1550         cmd->changed = true;
1551         return 0;
1552
1553 }
1554
1555 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1556 {
1557         int r;
1558         unsigned i;
1559         for (i = 0; i < nr_bits; i++) {
1560                 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1561                 if (r)
1562                         return r;
1563         }
1564
1565         return 0;
1566 }
1567
1568 static int is_dirty_callback(uint32_t index, bool *value, void *context)
1569 {
1570         unsigned long *bits = context;
1571         *value = test_bit(index, bits);
1572         return 0;
1573 }
1574
1575 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1576 {
1577         int r = 0;
1578
1579         /* nr_bits is really just a sanity check */
1580         if (nr_bits != from_cblock(cmd->cache_blocks)) {
1581                 DMERR("dirty bitset is wrong size");
1582                 return -EINVAL;
1583         }
1584
1585         r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1586         if (r)
1587                 return r;
1588
1589         cmd->changed = true;
1590         return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1591 }
1592
1593 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1594                             unsigned nr_bits,
1595                             unsigned long *bits)
1596 {
1597         int r;
1598
1599         WRITE_LOCK(cmd);
1600         if (separate_dirty_bits(cmd))
1601                 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1602         else
1603                 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1604         WRITE_UNLOCK(cmd);
1605
1606         return r;
1607 }
1608
1609 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1610                                  struct dm_cache_statistics *stats)
1611 {
1612         READ_LOCK_VOID(cmd);
1613         *stats = cmd->stats;
1614         READ_UNLOCK(cmd);
1615 }
1616
1617 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1618                                  struct dm_cache_statistics *stats)
1619 {
1620         WRITE_LOCK_VOID(cmd);
1621         cmd->stats = *stats;
1622         WRITE_UNLOCK(cmd);
1623 }
1624
1625 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1626 {
1627         int r = -EINVAL;
1628         flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1629                                  clear_clean_shutdown);
1630
1631         WRITE_LOCK(cmd);
1632         if (cmd->fail_io)
1633                 goto out;
1634
1635         r = __commit_transaction(cmd, mutator);
1636         if (r)
1637                 goto out;
1638
1639         r = __begin_transaction(cmd);
1640 out:
1641         WRITE_UNLOCK(cmd);
1642         return r;
1643 }
1644
1645 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1646                                            dm_block_t *result)
1647 {
1648         int r = -EINVAL;
1649
1650         READ_LOCK(cmd);
1651         if (!cmd->fail_io)
1652                 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1653         READ_UNLOCK(cmd);
1654
1655         return r;
1656 }
1657
1658 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1659                                    dm_block_t *result)
1660 {
1661         int r = -EINVAL;
1662
1663         READ_LOCK(cmd);
1664         if (!cmd->fail_io)
1665                 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1666         READ_UNLOCK(cmd);
1667
1668         return r;
1669 }
1670
1671 /*----------------------------------------------------------------*/
1672
1673 static int get_hint(uint32_t index, void *value_le, void *context)
1674 {
1675         uint32_t value;
1676         struct dm_cache_policy *policy = context;
1677
1678         value = policy_get_hint(policy, to_cblock(index));
1679         *((__le32 *) value_le) = cpu_to_le32(value);
1680
1681         return 0;
1682 }
1683
1684 /*
1685  * It's quicker to always delete the hint array, and recreate with
1686  * dm_array_new().
1687  */
1688 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1689 {
1690         int r;
1691         size_t hint_size;
1692         const char *policy_name = dm_cache_policy_get_name(policy);
1693         const unsigned *policy_version = dm_cache_policy_get_version(policy);
1694
1695         if (!policy_name[0] ||
1696             (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1697                 return -EINVAL;
1698
1699         strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1700         memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1701
1702         hint_size = dm_cache_policy_get_hint_size(policy);
1703         if (!hint_size)
1704                 return 0; /* short-circuit hints initialization */
1705         cmd->policy_hint_size = hint_size;
1706
1707         if (cmd->hint_root) {
1708                 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1709                 if (r)
1710                         return r;
1711         }
1712
1713         return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1714                             from_cblock(cmd->cache_blocks),
1715                             get_hint, policy);
1716 }
1717
1718 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1719 {
1720         int r;
1721
1722         WRITE_LOCK(cmd);
1723         r = write_hints(cmd, policy);
1724         WRITE_UNLOCK(cmd);
1725
1726         return r;
1727 }
1728
1729 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1730 {
1731         int r;
1732
1733         READ_LOCK(cmd);
1734         r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1735         READ_UNLOCK(cmd);
1736
1737         return r;
1738 }
1739
1740 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1741 {
1742         WRITE_LOCK_VOID(cmd);
1743         dm_bm_set_read_only(cmd->bm);
1744         WRITE_UNLOCK(cmd);
1745 }
1746
1747 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1748 {
1749         WRITE_LOCK_VOID(cmd);
1750         dm_bm_set_read_write(cmd->bm);
1751         WRITE_UNLOCK(cmd);
1752 }
1753
1754 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1755 {
1756         int r;
1757         struct dm_block *sblock;
1758         struct cache_disk_superblock *disk_super;
1759
1760         WRITE_LOCK(cmd);
1761         set_bit(NEEDS_CHECK, &cmd->flags);
1762
1763         r = superblock_lock(cmd, &sblock);
1764         if (r) {
1765                 DMERR("couldn't read superblock");
1766                 goto out;
1767         }
1768
1769         disk_super = dm_block_data(sblock);
1770         disk_super->flags = cpu_to_le32(cmd->flags);
1771
1772         dm_bm_unlock(sblock);
1773
1774 out:
1775         WRITE_UNLOCK(cmd);
1776         return r;
1777 }
1778
1779 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1780 {
1781         READ_LOCK(cmd);
1782         *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1783         READ_UNLOCK(cmd);
1784
1785         return 0;
1786 }
1787
1788 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1789 {
1790         int r;
1791
1792         WRITE_LOCK(cmd);
1793         __destroy_persistent_data_objects(cmd);
1794         r = __create_persistent_data_objects(cmd, false);
1795         if (r)
1796                 cmd->fail_io = true;
1797         WRITE_UNLOCK(cmd);
1798
1799         return r;
1800 }