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 #include <linux/refcount.h>
  17
  18 /*----------------------------------------------------------------*/
  19
  20 #define DM_MSG_PREFIX   "cache metadata"
  21
  22 #define CACHE_SUPERBLOCK_MAGIC 06142003
  23 #define CACHE_SUPERBLOCK_LOCATION 0
  24
  25 /*
  26  * defines a range of metadata versions that this module can handle.
  27  */
  28 #define MIN_CACHE_VERSION 1
  29 #define MAX_CACHE_VERSION 2
  30
  31 /*
  32  *  3 for btree insert +
  33  *  2 for btree lookup used within space map
  34  */
  35 #define CACHE_MAX_CONCURRENT_LOCKS 5
  36 #define SPACE_MAP_ROOT_SIZE 128
  37
  38 enum superblock_flag_bits {
  39         /* for spotting crashes that would invalidate the dirty bitset */
  40         CLEAN_SHUTDOWN,
  41         /* metadata must be checked using the tools */
  42         NEEDS_CHECK,
  43 };
  44
  45 /*
  46  * Each mapping from cache block -> origin block carries a set of flags.
  47  */
  48 enum mapping_bits {
  49         /*
  50          * A valid mapping.  Because we're using an array we clear this
  51          * flag for an non existant mapping.
  52          */
  53         M_VALID = 1,
  54
  55         /*
  56          * The data on the cache is different from that on the origin.
  57          * This flag is only used by metadata format 1.
  58          */
  59         M_DIRTY = 2
  60 };
  61
  62 struct cache_disk_superblock {
  63         __le32 csum;
  64         __le32 flags;
  65         __le64 blocknr;
  66
  67         __u8 uuid[16];
  68         __le64 magic;
  69         __le32 version;
  70
  71         __u8 policy_name[CACHE_POLICY_NAME_SIZE];
  72         __le32 policy_hint_size;
  73
  74         __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
  75         __le64 mapping_root;
  76         __le64 hint_root;
  77
  78         __le64 discard_root;
  79         __le64 discard_block_size;
  80         __le64 discard_nr_blocks;
  81
  82         __le32 data_block_size;
  83         __le32 metadata_block_size;
  84         __le32 cache_blocks;
  85
  86         __le32 compat_flags;
  87         __le32 compat_ro_flags;
  88         __le32 incompat_flags;
  89
  90         __le32 read_hits;
  91         __le32 read_misses;
  92         __le32 write_hits;
  93         __le32 write_misses;
  94
  95         __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
  96
  97         /*
  98          * Metadata format 2 fields.
  99          */
 100         __le64 dirty_root;
 101 } __packed;
 102
 103 struct dm_cache_metadata {
 104         refcount_t ref_count;
 105         struct list_head list;
 106
 107         unsigned version;
 108         struct block_device *bdev;
 109         struct dm_block_manager *bm;
 110         struct dm_space_map *metadata_sm;
 111         struct dm_transaction_manager *tm;
 112
 113         struct dm_array_info info;
 114         struct dm_array_info hint_info;
 115         struct dm_disk_bitset discard_info;
 116
 117         struct rw_semaphore root_lock;
 118         unsigned long flags;
 119         dm_block_t root;
 120         dm_block_t hint_root;
 121         dm_block_t discard_root;
 122
 123         sector_t discard_block_size;
 124         dm_dblock_t discard_nr_blocks;
 125
 126         sector_t data_block_size;
 127         dm_cblock_t cache_blocks;
 128         bool changed:1;
 129         bool clean_when_opened:1;
 130
 131         char policy_name[CACHE_POLICY_NAME_SIZE];
 132         unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
 133         size_t policy_hint_size;
 134         struct dm_cache_statistics stats;
 135
 136         /*
 137          * Reading the space map root can fail, so we read it into this
 138          * buffer before the superblock is locked and updated.
 139          */
 140         __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
 141
 142         /*
 143          * Set if a transaction has to be aborted but the attempt to roll
 144          * back to the previous (good) transaction failed.  The only
 145          * metadata operation permissible in this state is the closing of
 146          * the device.
 147          */
 148         bool fail_io:1;
 149
 150         /*
 151          * Metadata format 2 fields.
 152          */
 153         dm_block_t dirty_root;
 154         struct dm_disk_bitset dirty_info;
 155
 156         /*
 157          * These structures are used when loading metadata.  They're too
 158          * big to put on the stack.
 159          */
 160         struct dm_array_cursor mapping_cursor;
 161         struct dm_array_cursor hint_cursor;
 162         struct dm_bitset_cursor dirty_cursor;
 163 };
 164
 165 /*-------------------------------------------------------------------
 166  * superblock validator
 167  *-----------------------------------------------------------------*/
 168
 169 #define SUPERBLOCK_CSUM_XOR 9031977
 170
 171 static void sb_prepare_for_write(struct dm_block_validator *v,
 172                                  struct dm_block *b,
 173                                  size_t sb_block_size)
 174 {
 175         struct cache_disk_superblock *disk_super = dm_block_data(b);
 176
 177         disk_super->blocknr = cpu_to_le64(dm_block_location(b));
 178         disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 179                                                       sb_block_size - sizeof(__le32),
 180                                                       SUPERBLOCK_CSUM_XOR));
 181 }
 182
 183 static int check_metadata_version(struct cache_disk_superblock *disk_super)
 184 {
 185         uint32_t metadata_version = le32_to_cpu(disk_super->version);
 186
 187         if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
 188                 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
 189                       metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
 190                 return -EINVAL;
 191         }
 192
 193         return 0;
 194 }
 195
 196 static int sb_check(struct dm_block_validator *v,
 197                     struct dm_block *b,
 198                     size_t sb_block_size)
 199 {
 200         struct cache_disk_superblock *disk_super = dm_block_data(b);
 201         __le32 csum_le;
 202
 203         if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
 204                 DMERR("sb_check failed: blocknr %llu: wanted %llu",
 205                       le64_to_cpu(disk_super->blocknr),
 206                       (unsigned long long)dm_block_location(b));
 207                 return -ENOTBLK;
 208         }
 209
 210         if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
 211                 DMERR("sb_check failed: magic %llu: wanted %llu",
 212                       le64_to_cpu(disk_super->magic),
 213                       (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
 214                 return -EILSEQ;
 215         }
 216
 217         csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 218                                              sb_block_size - sizeof(__le32),
 219                                              SUPERBLOCK_CSUM_XOR));
 220         if (csum_le != disk_super->csum) {
 221                 DMERR("sb_check failed: csum %u: wanted %u",
 222                       le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
 223                 return -EILSEQ;
 224         }
 225
 226         return check_metadata_version(disk_super);
 227 }
 228
 229 static struct dm_block_validator sb_validator = {
 230         .name = "superblock",
 231         .prepare_for_write = sb_prepare_for_write,
 232         .check = sb_check
 233 };
 234
 235 /*----------------------------------------------------------------*/
 236
 237 static int superblock_read_lock(struct dm_cache_metadata *cmd,
 238                                 struct dm_block **sblock)
 239 {
 240         return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 241                                &sb_validator, sblock);
 242 }
 243
 244 static int superblock_lock_zero(struct dm_cache_metadata *cmd,
 245                                 struct dm_block **sblock)
 246 {
 247         return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 248                                      &sb_validator, sblock);
 249 }
 250
 251 static int superblock_lock(struct dm_cache_metadata *cmd,
 252                            struct dm_block **sblock)
 253 {
 254         return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 255                                 &sb_validator, sblock);
 256 }
 257
 258 /*----------------------------------------------------------------*/
 259
 260 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
 261 {
 262         int r;
 263         unsigned i;
 264         struct dm_block *b;
 265         __le64 *data_le, zero = cpu_to_le64(0);
 266         unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
 267
 268         /*
 269          * We can't use a validator here - it may be all zeroes.
 270          */
 271         r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
 272         if (r)
 273                 return r;
 274
 275         data_le = dm_block_data(b);
 276         *result = true;
 277         for (i = 0; i < sb_block_size; i++) {
 278                 if (data_le[i] != zero) {
 279                         *result = false;
 280                         break;
 281                 }
 282         }
 283
 284         dm_bm_unlock(b);
 285
 286         return 0;
 287 }
 288
 289 static void __setup_mapping_info(struct dm_cache_metadata *cmd)
 290 {
 291         struct dm_btree_value_type vt;
 292
 293         vt.context = NULL;
 294         vt.size = sizeof(__le64);
 295         vt.inc = NULL;
 296         vt.dec = NULL;
 297         vt.equal = NULL;
 298         dm_array_info_init(&cmd->info, cmd->tm, &vt);
 299
 300         if (cmd->policy_hint_size) {
 301                 vt.size = sizeof(__le32);
 302                 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
 303         }
 304 }
 305
 306 static int __save_sm_root(struct dm_cache_metadata *cmd)
 307 {
 308         int r;
 309         size_t metadata_len;
 310
 311         r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
 312         if (r < 0)
 313                 return r;
 314
 315         return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
 316                                metadata_len);
 317 }
 318
 319 static void __copy_sm_root(struct dm_cache_metadata *cmd,
 320                            struct cache_disk_superblock *disk_super)
 321 {
 322         memcpy(&disk_super->metadata_space_map_root,
 323                &cmd->metadata_space_map_root,
 324                sizeof(cmd->metadata_space_map_root));
 325 }
 326
 327 static bool separate_dirty_bits(struct dm_cache_metadata *cmd)
 328 {
 329         return cmd->version >= 2;
 330 }
 331
 332 static int __write_initial_superblock(struct dm_cache_metadata *cmd)
 333 {
 334         int r;
 335         struct dm_block *sblock;
 336         struct cache_disk_superblock *disk_super;
 337         sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
 338
 339         /* FIXME: see if we can lose the max sectors limit */
 340         if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
 341                 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
 342
 343         r = dm_tm_pre_commit(cmd->tm);
 344         if (r < 0)
 345                 return r;
 346
 347         /*
 348          * dm_sm_copy_root() can fail.  So we need to do it before we start
 349          * updating the superblock.
 350          */
 351         r = __save_sm_root(cmd);
 352         if (r)
 353                 return r;
 354
 355         r = superblock_lock_zero(cmd, &sblock);
 356         if (r)
 357                 return r;
 358
 359         disk_super = dm_block_data(sblock);
 360         disk_super->flags = 0;
 361         memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
 362         disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
 363         disk_super->version = cpu_to_le32(cmd->version);
 364         memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
 365         memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
 366         disk_super->policy_hint_size = cpu_to_le32(0);
 367
 368         __copy_sm_root(cmd, disk_super);
 369
 370         disk_super->mapping_root = cpu_to_le64(cmd->root);
 371         disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 372         disk_super->discard_root = cpu_to_le64(cmd->discard_root);
 373         disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
 374         disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
 375         disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
 376         disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
 377         disk_super->cache_blocks = cpu_to_le32(0);
 378
 379         disk_super->read_hits = cpu_to_le32(0);
 380         disk_super->read_misses = cpu_to_le32(0);
 381         disk_super->write_hits = cpu_to_le32(0);
 382         disk_super->write_misses = cpu_to_le32(0);
 383
 384         if (separate_dirty_bits(cmd))
 385                 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
 386
 387         return dm_tm_commit(cmd->tm, sblock);
 388 }
 389
 390 static int __format_metadata(struct dm_cache_metadata *cmd)
 391 {
 392         int r;
 393
 394         r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 395                                  &cmd->tm, &cmd->metadata_sm);
 396         if (r < 0) {
 397                 DMERR("tm_create_with_sm failed");
 398                 return r;
 399         }
 400
 401         __setup_mapping_info(cmd);
 402
 403         r = dm_array_empty(&cmd->info, &cmd->root);
 404         if (r < 0)
 405                 goto bad;
 406
 407         if (separate_dirty_bits(cmd)) {
 408                 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
 409                 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root);
 410                 if (r < 0)
 411                         goto bad;
 412         }
 413
 414         dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
 415         r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
 416         if (r < 0)
 417                 goto bad;
 418
 419         cmd->discard_block_size = 0;
 420         cmd->discard_nr_blocks = 0;
 421
 422         r = __write_initial_superblock(cmd);
 423         if (r)
 424                 goto bad;
 425
 426         cmd->clean_when_opened = true;
 427         return 0;
 428
 429 bad:
 430         dm_tm_destroy(cmd->tm);
 431         dm_sm_destroy(cmd->metadata_sm);
 432
 433         return r;
 434 }
 435
 436 static int __check_incompat_features(struct cache_disk_superblock *disk_super,
 437                                      struct dm_cache_metadata *cmd)
 438 {
 439         uint32_t incompat_flags, features;
 440
 441         incompat_flags = le32_to_cpu(disk_super->incompat_flags);
 442         features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
 443         if (features) {
 444                 DMERR("could not access metadata due to unsupported optional features (%lx).",
 445                       (unsigned long)features);
 446                 return -EINVAL;
 447         }
 448
 449         /*
 450          * Check for read-only metadata to skip the following RDWR checks.
 451          */
 452         if (get_disk_ro(cmd->bdev->bd_disk))
 453                 return 0;
 454
 455         features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
 456         if (features) {
 457                 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
 458                       (unsigned long)features);
 459                 return -EINVAL;
 460         }
 461
 462         return 0;
 463 }
 464
 465 static int __open_metadata(struct dm_cache_metadata *cmd)
 466 {
 467         int r;
 468         struct dm_block *sblock;
 469         struct cache_disk_superblock *disk_super;
 470         unsigned long sb_flags;
 471
 472         r = superblock_read_lock(cmd, &sblock);
 473         if (r < 0) {
 474                 DMERR("couldn't read lock superblock");
 475                 return r;
 476         }
 477
 478         disk_super = dm_block_data(sblock);
 479
 480         /* Verify the data block size hasn't changed */
 481         if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
 482                 DMERR("changing the data block size (from %u to %llu) is not supported",
 483                       le32_to_cpu(disk_super->data_block_size),
 484                       (unsigned long long)cmd->data_block_size);
 485                 r = -EINVAL;
 486                 goto bad;
 487         }
 488
 489         r = __check_incompat_features(disk_super, cmd);
 490         if (r < 0)
 491                 goto bad;
 492
 493         r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
 494                                disk_super->metadata_space_map_root,
 495                                sizeof(disk_super->metadata_space_map_root),
 496                                &cmd->tm, &cmd->metadata_sm);
 497         if (r < 0) {
 498                 DMERR("tm_open_with_sm failed");
 499                 goto bad;
 500         }
 501
 502         __setup_mapping_info(cmd);
 503         dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
 504         dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
 505         sb_flags = le32_to_cpu(disk_super->flags);
 506         cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
 507         dm_bm_unlock(sblock);
 508
 509         return 0;
 510
 511 bad:
 512         dm_bm_unlock(sblock);
 513         return r;
 514 }
 515
 516 static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
 517                                      bool format_device)
 518 {
 519         int r;
 520         bool unformatted = false;
 521
 522         r = __superblock_all_zeroes(cmd->bm, &unformatted);
 523         if (r)
 524                 return r;
 525
 526         if (unformatted)
 527                 return format_device ? __format_metadata(cmd) : -EPERM;
 528
 529         return __open_metadata(cmd);
 530 }
 531
 532 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
 533                                             bool may_format_device)
 534 {
 535         int r;
 536         cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
 537                                           CACHE_MAX_CONCURRENT_LOCKS);
 538         if (IS_ERR(cmd->bm)) {
 539                 DMERR("could not create block manager");
 540                 r = PTR_ERR(cmd->bm);
 541                 cmd->bm = NULL;
 542                 return r;
 543         }
 544
 545         r = __open_or_format_metadata(cmd, may_format_device);
 546         if (r) {
 547                 dm_block_manager_destroy(cmd->bm);
 548                 cmd->bm = NULL;
 549         }
 550
 551         return r;
 552 }
 553
 554 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
 555 {
 556         dm_sm_destroy(cmd->metadata_sm);
 557         dm_tm_destroy(cmd->tm);
 558         dm_block_manager_destroy(cmd->bm);
 559 }
 560
 561 typedef unsigned long (*flags_mutator)(unsigned long);
 562
 563 static void update_flags(struct cache_disk_superblock *disk_super,
 564                          flags_mutator mutator)
 565 {
 566         uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
 567         disk_super->flags = cpu_to_le32(sb_flags);
 568 }
 569
 570 static unsigned long set_clean_shutdown(unsigned long flags)
 571 {
 572         set_bit(CLEAN_SHUTDOWN, &flags);
 573         return flags;
 574 }
 575
 576 static unsigned long clear_clean_shutdown(unsigned long flags)
 577 {
 578         clear_bit(CLEAN_SHUTDOWN, &flags);
 579         return flags;
 580 }
 581
 582 static void read_superblock_fields(struct dm_cache_metadata *cmd,
 583                                    struct cache_disk_superblock *disk_super)
 584 {
 585         cmd->version = le32_to_cpu(disk_super->version);
 586         cmd->flags = le32_to_cpu(disk_super->flags);
 587         cmd->root = le64_to_cpu(disk_super->mapping_root);
 588         cmd->hint_root = le64_to_cpu(disk_super->hint_root);
 589         cmd->discard_root = le64_to_cpu(disk_super->discard_root);
 590         cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
 591         cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
 592         cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
 593         cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
 594         strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
 595         cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
 596         cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
 597         cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
 598         cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
 599
 600         cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
 601         cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
 602         cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
 603         cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
 604
 605         if (separate_dirty_bits(cmd))
 606                 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
 607
 608         cmd->changed = false;
 609 }
 610
 611 /*
 612  * The mutator updates the superblock flags.
 613  */
 614 static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
 615                                      flags_mutator mutator)
 616 {
 617         int r;
 618         struct cache_disk_superblock *disk_super;
 619         struct dm_block *sblock;
 620
 621         r = superblock_lock(cmd, &sblock);
 622         if (r)
 623                 return r;
 624
 625         disk_super = dm_block_data(sblock);
 626         update_flags(disk_super, mutator);
 627         read_superblock_fields(cmd, disk_super);
 628         dm_bm_unlock(sblock);
 629
 630         return dm_bm_flush(cmd->bm);
 631 }
 632
 633 static int __begin_transaction(struct dm_cache_metadata *cmd)
 634 {
 635         int r;
 636         struct cache_disk_superblock *disk_super;
 637         struct dm_block *sblock;
 638
 639         /*
 640          * We re-read the superblock every time.  Shouldn't need to do this
 641          * really.
 642          */
 643         r = superblock_read_lock(cmd, &sblock);
 644         if (r)
 645                 return r;
 646
 647         disk_super = dm_block_data(sblock);
 648         read_superblock_fields(cmd, disk_super);
 649         dm_bm_unlock(sblock);
 650
 651         return 0;
 652 }
 653
 654 static int __commit_transaction(struct dm_cache_metadata *cmd,
 655                                 flags_mutator mutator)
 656 {
 657         int r;
 658         struct cache_disk_superblock *disk_super;
 659         struct dm_block *sblock;
 660
 661         /*
 662          * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
 663          */
 664         BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
 665
 666         if (separate_dirty_bits(cmd)) {
 667                 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
 668                                     &cmd->dirty_root);
 669                 if (r)
 670                         return r;
 671         }
 672
 673         r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
 674                             &cmd->discard_root);
 675         if (r)
 676                 return r;
 677
 678         r = dm_tm_pre_commit(cmd->tm);
 679         if (r < 0)
 680                 return r;
 681
 682         r = __save_sm_root(cmd);
 683         if (r)
 684                 return r;
 685
 686         r = superblock_lock(cmd, &sblock);
 687         if (r)
 688                 return r;
 689
 690         disk_super = dm_block_data(sblock);
 691
 692         disk_super->flags = cpu_to_le32(cmd->flags);
 693         if (mutator)
 694                 update_flags(disk_super, mutator);
 695
 696         disk_super->mapping_root = cpu_to_le64(cmd->root);
 697         if (separate_dirty_bits(cmd))
 698                 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
 699         disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 700         disk_super->discard_root = cpu_to_le64(cmd->discard_root);
 701         disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
 702         disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
 703         disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
 704         strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
 705         disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
 706         disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
 707         disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
 708         disk_super->policy_hint_size = cpu_to_le32(cmd->policy_hint_size);
 709
 710         disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
 711         disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
 712         disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
 713         disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
 714         __copy_sm_root(cmd, disk_super);
 715
 716         return dm_tm_commit(cmd->tm, sblock);
 717 }
 718
 719 /*----------------------------------------------------------------*/
 720
 721 /*
 722  * The mappings are held in a dm-array that has 64-bit values stored in
 723  * little-endian format.  The index is the cblock, the high 48bits of the
 724  * value are the oblock and the low 16 bit the flags.
 725  */
 726 #define FLAGS_MASK ((1 << 16) - 1)
 727
 728 static __le64 pack_value(dm_oblock_t block, unsigned flags)
 729 {
 730         uint64_t value = from_oblock(block);
 731         value <<= 16;
 732         value = value | (flags & FLAGS_MASK);
 733         return cpu_to_le64(value);
 734 }
 735
 736 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
 737 {
 738         uint64_t value = le64_to_cpu(value_le);
 739         uint64_t b = value >> 16;
 740         *block = to_oblock(b);
 741         *flags = value & FLAGS_MASK;
 742 }
 743
 744 /*----------------------------------------------------------------*/
 745
 746 static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
 747                                                sector_t data_block_size,
 748                                                bool may_format_device,
 749                                                size_t policy_hint_size,
 750                                                unsigned metadata_version)
 751 {
 752         int r;
 753         struct dm_cache_metadata *cmd;
 754
 755         cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
 756         if (!cmd) {
 757                 DMERR("could not allocate metadata struct");
 758                 return ERR_PTR(-ENOMEM);
 759         }
 760
 761         cmd->version = metadata_version;
 762         refcount_set(&cmd->ref_count, 1);
 763         init_rwsem(&cmd->root_lock);
 764         cmd->bdev = bdev;
 765         cmd->data_block_size = data_block_size;
 766         cmd->cache_blocks = 0;
 767         cmd->policy_hint_size = policy_hint_size;
 768         cmd->changed = true;
 769         cmd->fail_io = false;
 770
 771         r = __create_persistent_data_objects(cmd, may_format_device);
 772         if (r) {
 773                 kfree(cmd);
 774                 return ERR_PTR(r);
 775         }
 776
 777         r = __begin_transaction_flags(cmd, clear_clean_shutdown);
 778         if (r < 0) {
 779                 dm_cache_metadata_close(cmd);
 780                 return ERR_PTR(r);
 781         }
 782
 783         return cmd;
 784 }
 785
 786 /*
 787  * We keep a little list of ref counted metadata objects to prevent two
 788  * different target instances creating separate bufio instances.  This is
 789  * an issue if a table is reloaded before the suspend.
 790  */
 791 static DEFINE_MUTEX(table_lock);
 792 static LIST_HEAD(table);
 793
 794 static struct dm_cache_metadata *lookup(struct block_device *bdev)
 795 {
 796         struct dm_cache_metadata *cmd;
 797
 798         list_for_each_entry(cmd, &table, list)
 799                 if (cmd->bdev == bdev) {
 800                         refcount_inc(&cmd->ref_count);
 801                         return cmd;
 802                 }
 803
 804         return NULL;
 805 }
 806
 807 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
 808                                                 sector_t data_block_size,
 809                                                 bool may_format_device,
 810                                                 size_t policy_hint_size,
 811                                                 unsigned metadata_version)
 812 {
 813         struct dm_cache_metadata *cmd, *cmd2;
 814
 815         mutex_lock(&table_lock);
 816         cmd = lookup(bdev);
 817         mutex_unlock(&table_lock);
 818
 819         if (cmd)
 820                 return cmd;
 821
 822         cmd = metadata_open(bdev, data_block_size, may_format_device,
 823                             policy_hint_size, metadata_version);
 824         if (!IS_ERR(cmd)) {
 825                 mutex_lock(&table_lock);
 826                 cmd2 = lookup(bdev);
 827                 if (cmd2) {
 828                         mutex_unlock(&table_lock);
 829                         __destroy_persistent_data_objects(cmd);
 830                         kfree(cmd);
 831                         return cmd2;
 832                 }
 833                 list_add(&cmd->list, &table);
 834                 mutex_unlock(&table_lock);
 835         }
 836
 837         return cmd;
 838 }
 839
 840 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
 841 {
 842         if (cmd->data_block_size != data_block_size) {
 843                 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
 844                       (unsigned long long) data_block_size,
 845                       (unsigned long long) cmd->data_block_size);
 846                 return false;
 847         }
 848
 849         return true;
 850 }
 851
 852 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
 853                                                  sector_t data_block_size,
 854                                                  bool may_format_device,
 855                                                  size_t policy_hint_size,
 856                                                  unsigned metadata_version)
 857 {
 858         struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
 859                                                        policy_hint_size, metadata_version);
 860
 861         if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
 862                 dm_cache_metadata_close(cmd);
 863                 return ERR_PTR(-EINVAL);
 864         }
 865
 866         return cmd;
 867 }
 868
 869 void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
 870 {
 871         if (refcount_dec_and_test(&cmd->ref_count)) {
 872                 mutex_lock(&table_lock);
 873                 list_del(&cmd->list);
 874                 mutex_unlock(&table_lock);
 875
 876                 if (!cmd->fail_io)
 877                         __destroy_persistent_data_objects(cmd);
 878                 kfree(cmd);
 879         }
 880 }
 881
 882 /*
 883  * Checks that the given cache block is either unmapped or clean.
 884  */
 885 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
 886                                       bool *result)
 887 {
 888         int r;
 889         __le64 value;
 890         dm_oblock_t ob;
 891         unsigned flags;
 892
 893         r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
 894         if (r)
 895                 return r;
 896
 897         unpack_value(value, &ob, &flags);
 898         *result = !((flags & M_VALID) && (flags & M_DIRTY));
 899
 900         return 0;
 901 }
 902
 903 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
 904                                            dm_cblock_t begin, dm_cblock_t end,
 905                                            bool *result)
 906 {
 907         int r;
 908         *result = true;
 909
 910         while (begin != end) {
 911                 r = block_clean_combined_dirty(cmd, begin, result);
 912                 if (r) {
 913                         DMERR("block_clean_combined_dirty failed");
 914                         return r;
 915                 }
 916
 917                 if (!*result) {
 918                         DMERR("cache block %llu is dirty",
 919                               (unsigned long long) from_cblock(begin));
 920                         return 0;
 921                 }
 922
 923                 begin = to_cblock(from_cblock(begin) + 1);
 924         }
 925
 926         return 0;
 927 }
 928
 929 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
 930                                            dm_cblock_t begin, dm_cblock_t end,
 931                                            bool *result)
 932 {
 933         int r;
 934         bool dirty_flag;
 935         *result = true;
 936
 937         if (from_cblock(cmd->cache_blocks) == 0)
 938                 /* Nothing to do */
 939                 return 0;
 940
 941         r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
 942                                    from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
 943         if (r) {
 944                 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__);
 945                 return r;
 946         }
 947
 948         r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin));
 949         if (r) {
 950                 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
 951                 dm_bitset_cursor_end(&cmd->dirty_cursor);
 952                 return r;
 953         }
 954
 955         while (begin != end) {
 956                 /*
 957                  * We assume that unmapped blocks have their dirty bit
 958                  * cleared.
 959                  */
 960                 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor);
 961                 if (dirty_flag) {
 962                         DMERR("%s: cache block %llu is dirty", __func__,
 963                               (unsigned long long) from_cblock(begin));
 964                         dm_bitset_cursor_end(&cmd->dirty_cursor);
 965                         *result = false;
 966                         return 0;
 967                 }
 968
 969                 begin = to_cblock(from_cblock(begin) + 1);
 970                 if (begin == end)
 971                         break;
 972
 973                 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
 974                 if (r) {
 975                         DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
 976                         dm_bitset_cursor_end(&cmd->dirty_cursor);
 977                         return r;
 978                 }
 979         }
 980
 981         dm_bitset_cursor_end(&cmd->dirty_cursor);
 982
 983         return 0;
 984 }
 985
 986 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
 987                                         dm_cblock_t begin, dm_cblock_t end,
 988                                         bool *result)
 989 {
 990         if (separate_dirty_bits(cmd))
 991                 return blocks_are_clean_separate_dirty(cmd, begin, end, result);
 992         else
 993                 return blocks_are_clean_combined_dirty(cmd, begin, end, result);
 994 }
 995
 996 static bool cmd_write_lock(struct dm_cache_metadata *cmd)
 997 {
 998         down_write(&cmd->root_lock);
 999         if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
1000                 up_write(&cmd->root_lock);
1001                 return false;
1002         }
1003         return true;
1004 }
1005
1006 #define WRITE_LOCK(cmd)                         \
1007         do {                                    \
1008                 if (!cmd_write_lock((cmd)))     \
1009                         return -EINVAL;         \
1010         } while(0)
1011
1012 #define WRITE_LOCK_VOID(cmd)                    \
1013         do {                                    \
1014                 if (!cmd_write_lock((cmd)))     \
1015                         return;                 \
1016         } while(0)
1017
1018 #define WRITE_UNLOCK(cmd) \
1019         up_write(&(cmd)->root_lock)
1020
1021 static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1022 {
1023         down_read(&cmd->root_lock);
1024         if (cmd->fail_io) {
1025                 up_read(&cmd->root_lock);
1026                 return false;
1027         }
1028         return true;
1029 }
1030
1031 #define READ_LOCK(cmd)                          \
1032         do {                                    \
1033                 if (!cmd_read_lock((cmd)))      \
1034                         return -EINVAL;         \
1035         } while(0)
1036
1037 #define READ_LOCK_VOID(cmd)                     \
1038         do {                                    \
1039                 if (!cmd_read_lock((cmd)))      \
1040                         return;                 \
1041         } while(0)
1042
1043 #define READ_UNLOCK(cmd) \
1044         up_read(&(cmd)->root_lock)
1045
1046 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1047 {
1048         int r;
1049         bool clean;
1050         __le64 null_mapping = pack_value(0, 0);
1051
1052         WRITE_LOCK(cmd);
1053         __dm_bless_for_disk(&null_mapping);
1054
1055         if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1056                 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
1057                 if (r) {
1058                         __dm_unbless_for_disk(&null_mapping);
1059                         goto out;
1060                 }
1061
1062                 if (!clean) {
1063                         DMERR("unable to shrink cache due to dirty blocks");
1064                         r = -EINVAL;
1065                         __dm_unbless_for_disk(&null_mapping);
1066                         goto out;
1067                 }
1068         }
1069
1070         r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1071                             from_cblock(new_cache_size),
1072                             &null_mapping, &cmd->root);
1073         if (r)
1074                 goto out;
1075
1076         if (separate_dirty_bits(cmd)) {
1077                 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1078                                      from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1079                                      false, &cmd->dirty_root);
1080                 if (r)
1081                         goto out;
1082         }
1083
1084         cmd->cache_blocks = new_cache_size;
1085         cmd->changed = true;
1086
1087 out:
1088         WRITE_UNLOCK(cmd);
1089
1090         return r;
1091 }
1092
1093 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1094                                    sector_t discard_block_size,
1095                                    dm_dblock_t new_nr_entries)
1096 {
1097         int r;
1098
1099         WRITE_LOCK(cmd);
1100         r = dm_bitset_resize(&cmd->discard_info,
1101                              cmd->discard_root,
1102                              from_dblock(cmd->discard_nr_blocks),
1103                              from_dblock(new_nr_entries),
1104                              false, &cmd->discard_root);
1105         if (!r) {
1106                 cmd->discard_block_size = discard_block_size;
1107                 cmd->discard_nr_blocks = new_nr_entries;
1108         }
1109
1110         cmd->changed = true;
1111         WRITE_UNLOCK(cmd);
1112
1113         return r;
1114 }
1115
1116 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1117 {
1118         return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
1119                                  from_dblock(b), &cmd->discard_root);
1120 }
1121
1122 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1123 {
1124         return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
1125                                    from_dblock(b), &cmd->discard_root);
1126 }
1127
1128 static int __discard(struct dm_cache_metadata *cmd,
1129                      dm_dblock_t dblock, bool discard)
1130 {
1131         int r;
1132
1133         r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1134         if (r)
1135                 return r;
1136
1137         cmd->changed = true;
1138         return 0;
1139 }
1140
1141 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1142                          dm_dblock_t dblock, bool discard)
1143 {
1144         int r;
1145
1146         WRITE_LOCK(cmd);
1147         r = __discard(cmd, dblock, discard);
1148         WRITE_UNLOCK(cmd);
1149
1150         return r;
1151 }
1152
1153 static int __load_discards(struct dm_cache_metadata *cmd,
1154                            load_discard_fn fn, void *context)
1155 {
1156         int r = 0;
1157         uint32_t b;
1158         struct dm_bitset_cursor c;
1159
1160         if (from_dblock(cmd->discard_nr_blocks) == 0)
1161                 /* nothing to do */
1162                 return 0;
1163
1164         if (cmd->clean_when_opened) {
1165                 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1166                 if (r)
1167                         return r;
1168
1169                 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1170                                            from_dblock(cmd->discard_nr_blocks), &c);
1171                 if (r)
1172                         return r;
1173
1174                 for (b = 0; ; b++) {
1175                         r = fn(context, cmd->discard_block_size, to_dblock(b),
1176                                dm_bitset_cursor_get_value(&c));
1177                         if (r)
1178                                 break;
1179
1180                         if (b >= (from_dblock(cmd->discard_nr_blocks) - 1))
1181                                 break;
1182
1183                         r = dm_bitset_cursor_next(&c);
1184                         if (r)
1185                                 break;
1186                 }
1187
1188                 dm_bitset_cursor_end(&c);
1189
1190         } else {
1191                 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1192                         r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1193                         if (r)
1194                                 return r;
1195                 }
1196         }
1197
1198         return r;
1199 }
1200
1201 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1202                            load_discard_fn fn, void *context)
1203 {
1204         int r;
1205
1206         READ_LOCK(cmd);
1207         r = __load_discards(cmd, fn, context);
1208         READ_UNLOCK(cmd);
1209
1210         return r;
1211 }
1212
1213 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1214 {
1215         READ_LOCK(cmd);
1216         *result = cmd->cache_blocks;
1217         READ_UNLOCK(cmd);
1218
1219         return 0;
1220 }
1221
1222 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1223 {
1224         int r;
1225         __le64 value = pack_value(0, 0);
1226
1227         __dm_bless_for_disk(&value);
1228         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1229                                &value, &cmd->root);
1230         if (r)
1231                 return r;
1232
1233         cmd->changed = true;
1234         return 0;
1235 }
1236
1237 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1238 {
1239         int r;
1240
1241         WRITE_LOCK(cmd);
1242         r = __remove(cmd, cblock);
1243         WRITE_UNLOCK(cmd);
1244
1245         return r;
1246 }
1247
1248 static int __insert(struct dm_cache_metadata *cmd,
1249                     dm_cblock_t cblock, dm_oblock_t oblock)
1250 {
1251         int r;
1252         __le64 value = pack_value(oblock, M_VALID);
1253         __dm_bless_for_disk(&value);
1254
1255         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1256                                &value, &cmd->root);
1257         if (r)
1258                 return r;
1259
1260         cmd->changed = true;
1261         return 0;
1262 }
1263
1264 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1265                             dm_cblock_t cblock, dm_oblock_t oblock)
1266 {
1267         int r;
1268
1269         WRITE_LOCK(cmd);
1270         r = __insert(cmd, cblock, oblock);
1271         WRITE_UNLOCK(cmd);
1272
1273         return r;
1274 }
1275
1276 struct thunk {
1277         load_mapping_fn fn;
1278         void *context;
1279
1280         struct dm_cache_metadata *cmd;
1281         bool respect_dirty_flags;
1282         bool hints_valid;
1283 };
1284
1285 static bool policy_unchanged(struct dm_cache_metadata *cmd,
1286                              struct dm_cache_policy *policy)
1287 {
1288         const char *policy_name = dm_cache_policy_get_name(policy);
1289         const unsigned *policy_version = dm_cache_policy_get_version(policy);
1290         size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1291
1292         /*
1293          * Ensure policy names match.
1294          */
1295         if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1296                 return false;
1297
1298         /*
1299          * Ensure policy major versions match.
1300          */
1301         if (cmd->policy_version[0] != policy_version[0])
1302                 return false;
1303
1304         /*
1305          * Ensure policy hint sizes match.
1306          */
1307         if (cmd->policy_hint_size != policy_hint_size)
1308                 return false;
1309
1310         return true;
1311 }
1312
1313 static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1314 {
1315         return cmd->hint_root && cmd->policy_hint_size;
1316 }
1317
1318 static bool hints_array_available(struct dm_cache_metadata *cmd,
1319                                   struct dm_cache_policy *policy)
1320 {
1321         return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1322                 hints_array_initialized(cmd);
1323 }
1324
1325 static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1326                              uint64_t cb, bool hints_valid,
1327                              struct dm_array_cursor *mapping_cursor,
1328                              struct dm_array_cursor *hint_cursor,
1329                              load_mapping_fn fn, void *context)
1330 {
1331         int r = 0;
1332
1333         __le64 mapping;
1334         __le32 hint = 0;
1335
1336         __le64 *mapping_value_le;
1337         __le32 *hint_value_le;
1338
1339         dm_oblock_t oblock;
1340         unsigned flags;
1341         bool dirty = true;
1342
1343         dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1344         memcpy(&mapping, mapping_value_le, sizeof(mapping));
1345         unpack_value(mapping, &oblock, &flags);
1346
1347         if (flags & M_VALID) {
1348                 if (hints_valid) {
1349                         dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1350                         memcpy(&hint, hint_value_le, sizeof(hint));
1351                 }
1352                 if (cmd->clean_when_opened)
1353                         dirty = flags & M_DIRTY;
1354
1355                 r = fn(context, oblock, to_cblock(cb), dirty,
1356                        le32_to_cpu(hint), hints_valid);
1357                 if (r) {
1358                         DMERR("policy couldn't load cache block %llu",
1359                               (unsigned long long) from_cblock(to_cblock(cb)));
1360                 }
1361         }
1362
1363         return r;
1364 }
1365
1366 static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1367                              uint64_t cb, bool hints_valid,
1368                              struct dm_array_cursor *mapping_cursor,
1369                              struct dm_array_cursor *hint_cursor,
1370                              struct dm_bitset_cursor *dirty_cursor,
1371                              load_mapping_fn fn, void *context)
1372 {
1373         int r = 0;
1374
1375         __le64 mapping;
1376         __le32 hint = 0;
1377
1378         __le64 *mapping_value_le;
1379         __le32 *hint_value_le;
1380
1381         dm_oblock_t oblock;
1382         unsigned flags;
1383         bool dirty = true;
1384
1385         dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1386         memcpy(&mapping, mapping_value_le, sizeof(mapping));
1387         unpack_value(mapping, &oblock, &flags);
1388
1389         if (flags & M_VALID) {
1390                 if (hints_valid) {
1391                         dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1392                         memcpy(&hint, hint_value_le, sizeof(hint));
1393                 }
1394                 if (cmd->clean_when_opened)
1395                         dirty = dm_bitset_cursor_get_value(dirty_cursor);
1396
1397                 r = fn(context, oblock, to_cblock(cb), dirty,
1398                        le32_to_cpu(hint), hints_valid);
1399                 if (r) {
1400                         DMERR("policy couldn't load cache block %llu",
1401                               (unsigned long long) from_cblock(to_cblock(cb)));
1402                 }
1403         }
1404
1405         return r;
1406 }
1407
1408 static int __load_mappings(struct dm_cache_metadata *cmd,
1409                            struct dm_cache_policy *policy,
1410                            load_mapping_fn fn, void *context)
1411 {
1412         int r;
1413         uint64_t cb;
1414
1415         bool hints_valid = hints_array_available(cmd, policy);
1416
1417         if (from_cblock(cmd->cache_blocks) == 0)
1418                 /* Nothing to do */
1419                 return 0;
1420
1421         r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1422         if (r)
1423                 return r;
1424
1425         if (hints_valid) {
1426                 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1427                 if (r) {
1428                         dm_array_cursor_end(&cmd->mapping_cursor);
1429                         return r;
1430                 }
1431         }
1432
1433         if (separate_dirty_bits(cmd)) {
1434                 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1435                                            from_cblock(cmd->cache_blocks),
1436                                            &cmd->dirty_cursor);
1437                 if (r) {
1438                         dm_array_cursor_end(&cmd->hint_cursor);
1439                         dm_array_cursor_end(&cmd->mapping_cursor);
1440                         return r;
1441                 }
1442         }
1443
1444         for (cb = 0; ; cb++) {
1445                 if (separate_dirty_bits(cmd))
1446                         r = __load_mapping_v2(cmd, cb, hints_valid,
1447                                               &cmd->mapping_cursor,
1448                                               &cmd->hint_cursor,
1449                                               &cmd->dirty_cursor,
1450                                               fn, context);
1451                 else
1452                         r = __load_mapping_v1(cmd, cb, hints_valid,
1453                                               &cmd->mapping_cursor, &cmd->hint_cursor,
1454                                               fn, context);
1455                 if (r)
1456                         goto out;
1457
1458                 /*
1459                  * We need to break out before we move the cursors.
1460                  */
1461                 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1462                         break;
1463
1464                 r = dm_array_cursor_next(&cmd->mapping_cursor);
1465                 if (r) {
1466                         DMERR("dm_array_cursor_next for mapping failed");
1467                         goto out;
1468                 }
1469
1470                 if (hints_valid) {
1471                         r = dm_array_cursor_next(&cmd->hint_cursor);
1472                         if (r) {
1473                                 dm_array_cursor_end(&cmd->hint_cursor);
1474                                 hints_valid = false;
1475                         }
1476                 }
1477
1478                 if (separate_dirty_bits(cmd)) {
1479                         r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1480                         if (r) {
1481                                 DMERR("dm_bitset_cursor_next for dirty failed");
1482                                 goto out;
1483                         }
1484                 }
1485         }
1486 out:
1487         dm_array_cursor_end(&cmd->mapping_cursor);
1488         if (hints_valid)
1489                 dm_array_cursor_end(&cmd->hint_cursor);
1490
1491         if (separate_dirty_bits(cmd))
1492                 dm_bitset_cursor_end(&cmd->dirty_cursor);
1493
1494         return r;
1495 }
1496
1497 int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1498                            struct dm_cache_policy *policy,
1499                            load_mapping_fn fn, void *context)
1500 {
1501         int r;
1502
1503         READ_LOCK(cmd);
1504         r = __load_mappings(cmd, policy, fn, context);
1505         READ_UNLOCK(cmd);
1506
1507         return r;
1508 }
1509
1510 static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1511 {
1512         int r = 0;
1513         __le64 value;
1514         dm_oblock_t oblock;
1515         unsigned flags;
1516
1517         memcpy(&value, leaf, sizeof(value));
1518         unpack_value(value, &oblock, &flags);
1519
1520         return r;
1521 }
1522
1523 static int __dump_mappings(struct dm_cache_metadata *cmd)
1524 {
1525         return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1526 }
1527
1528 void dm_cache_dump(struct dm_cache_metadata *cmd)
1529 {
1530         READ_LOCK_VOID(cmd);
1531         __dump_mappings(cmd);
1532         READ_UNLOCK(cmd);
1533 }
1534
1535 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1536 {
1537         int r;
1538
1539         READ_LOCK(cmd);
1540         r = cmd->changed;
1541         READ_UNLOCK(cmd);
1542
1543         return r;
1544 }
1545
1546 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1547 {
1548         int r;
1549         unsigned flags;
1550         dm_oblock_t oblock;
1551         __le64 value;
1552
1553         r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1554         if (r)
1555                 return r;
1556
1557         unpack_value(value, &oblock, &flags);
1558
1559         if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1560                 /* nothing to be done */
1561                 return 0;
1562
1563         value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1564         __dm_bless_for_disk(&value);
1565
1566         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1567                                &value, &cmd->root);
1568         if (r)
1569                 return r;
1570
1571         cmd->changed = true;
1572         return 0;
1573
1574 }
1575
1576 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1577 {
1578         int r;
1579         unsigned i;
1580         for (i = 0; i < nr_bits; i++) {
1581                 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1582                 if (r)
1583                         return r;
1584         }
1585
1586         return 0;
1587 }
1588
1589 static int is_dirty_callback(uint32_t index, bool *value, void *context)
1590 {
1591         unsigned long *bits = context;
1592         *value = test_bit(index, bits);
1593         return 0;
1594 }
1595
1596 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1597 {
1598         int r = 0;
1599
1600         /* nr_bits is really just a sanity check */
1601         if (nr_bits != from_cblock(cmd->cache_blocks)) {
1602                 DMERR("dirty bitset is wrong size");
1603                 return -EINVAL;
1604         }
1605
1606         r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1607         if (r)
1608                 return r;
1609
1610         cmd->changed = true;
1611         return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1612 }
1613
1614 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1615                             unsigned nr_bits,
1616                             unsigned long *bits)
1617 {
1618         int r;
1619
1620         WRITE_LOCK(cmd);
1621         if (separate_dirty_bits(cmd))
1622                 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1623         else
1624                 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1625         WRITE_UNLOCK(cmd);
1626
1627         return r;
1628 }
1629
1630 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1631                                  struct dm_cache_statistics *stats)
1632 {
1633         READ_LOCK_VOID(cmd);
1634         *stats = cmd->stats;
1635         READ_UNLOCK(cmd);
1636 }
1637
1638 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1639                                  struct dm_cache_statistics *stats)
1640 {
1641         WRITE_LOCK_VOID(cmd);
1642         cmd->stats = *stats;
1643         WRITE_UNLOCK(cmd);
1644 }
1645
1646 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1647 {
1648         int r = -EINVAL;
1649         flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1650                                  clear_clean_shutdown);
1651
1652         WRITE_LOCK(cmd);
1653         if (cmd->fail_io)
1654                 goto out;
1655
1656         r = __commit_transaction(cmd, mutator);
1657         if (r)
1658                 goto out;
1659
1660         r = __begin_transaction(cmd);
1661 out:
1662         WRITE_UNLOCK(cmd);
1663         return r;
1664 }
1665
1666 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1667                                            dm_block_t *result)
1668 {
1669         int r = -EINVAL;
1670
1671         READ_LOCK(cmd);
1672         if (!cmd->fail_io)
1673                 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1674         READ_UNLOCK(cmd);
1675
1676         return r;
1677 }
1678
1679 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1680                                    dm_block_t *result)
1681 {
1682         int r = -EINVAL;
1683
1684         READ_LOCK(cmd);
1685         if (!cmd->fail_io)
1686                 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1687         READ_UNLOCK(cmd);
1688
1689         return r;
1690 }
1691
1692 /*----------------------------------------------------------------*/
1693
1694 static int get_hint(uint32_t index, void *value_le, void *context)
1695 {
1696         uint32_t value;
1697         struct dm_cache_policy *policy = context;
1698
1699         value = policy_get_hint(policy, to_cblock(index));
1700         *((__le32 *) value_le) = cpu_to_le32(value);
1701
1702         return 0;
1703 }
1704
1705 /*
1706  * It's quicker to always delete the hint array, and recreate with
1707  * dm_array_new().
1708  */
1709 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1710 {
1711         int r;
1712         size_t hint_size;
1713         const char *policy_name = dm_cache_policy_get_name(policy);
1714         const unsigned *policy_version = dm_cache_policy_get_version(policy);
1715
1716         if (!policy_name[0] ||
1717             (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1718                 return -EINVAL;
1719
1720         strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1721         memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1722
1723         hint_size = dm_cache_policy_get_hint_size(policy);
1724         if (!hint_size)
1725                 return 0; /* short-circuit hints initialization */
1726         cmd->policy_hint_size = hint_size;
1727
1728         if (cmd->hint_root) {
1729                 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1730                 if (r)
1731                         return r;
1732         }
1733
1734         return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1735                             from_cblock(cmd->cache_blocks),
1736                             get_hint, policy);
1737 }
1738
1739 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1740 {
1741         int r;
1742
1743         WRITE_LOCK(cmd);
1744         r = write_hints(cmd, policy);
1745         WRITE_UNLOCK(cmd);
1746
1747         return r;
1748 }
1749
1750 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1751 {
1752         int r;
1753
1754         READ_LOCK(cmd);
1755         r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1756         READ_UNLOCK(cmd);
1757
1758         return r;
1759 }
1760
1761 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1762 {
1763         WRITE_LOCK_VOID(cmd);
1764         dm_bm_set_read_only(cmd->bm);
1765         WRITE_UNLOCK(cmd);
1766 }
1767
1768 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1769 {
1770         WRITE_LOCK_VOID(cmd);
1771         dm_bm_set_read_write(cmd->bm);
1772         WRITE_UNLOCK(cmd);
1773 }
1774
1775 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1776 {
1777         int r;
1778         struct dm_block *sblock;
1779         struct cache_disk_superblock *disk_super;
1780
1781         WRITE_LOCK(cmd);
1782         set_bit(NEEDS_CHECK, &cmd->flags);
1783
1784         r = superblock_lock(cmd, &sblock);
1785         if (r) {
1786                 DMERR("couldn't read superblock");
1787                 goto out;
1788         }
1789
1790         disk_super = dm_block_data(sblock);
1791         disk_super->flags = cpu_to_le32(cmd->flags);
1792
1793         dm_bm_unlock(sblock);
1794
1795 out:
1796         WRITE_UNLOCK(cmd);
1797         return r;
1798 }
1799
1800 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1801 {
1802         READ_LOCK(cmd);
1803         *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1804         READ_UNLOCK(cmd);
1805
1806         return 0;
1807 }
1808
1809 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1810 {
1811         int r;
1812
1813         WRITE_LOCK(cmd);
1814         __destroy_persistent_data_objects(cmd);
1815         r = __create_persistent_data_objects(cmd, false);
1816         if (r)
1817                 cmd->fail_io = true;
1818         WRITE_UNLOCK(cmd);
1819
1820         return r;
1821 }