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 = 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                 return PTR_ERR(cmd->bm);
 541         }
 542
 543         r = __open_or_format_metadata(cmd, may_format_device);
 544         if (r)
 545                 dm_block_manager_destroy(cmd->bm);
 546
 547         return r;
 548 }
 549
 550 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
 551 {
 552         dm_sm_destroy(cmd->metadata_sm);
 553         dm_tm_destroy(cmd->tm);
 554         dm_block_manager_destroy(cmd->bm);
 555 }
 556
 557 typedef unsigned long (*flags_mutator)(unsigned long);
 558
 559 static void update_flags(struct cache_disk_superblock *disk_super,
 560                          flags_mutator mutator)
 561 {
 562         uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
 563         disk_super->flags = cpu_to_le32(sb_flags);
 564 }
 565
 566 static unsigned long set_clean_shutdown(unsigned long flags)
 567 {
 568         set_bit(CLEAN_SHUTDOWN, &flags);
 569         return flags;
 570 }
 571
 572 static unsigned long clear_clean_shutdown(unsigned long flags)
 573 {
 574         clear_bit(CLEAN_SHUTDOWN, &flags);
 575         return flags;
 576 }
 577
 578 static void read_superblock_fields(struct dm_cache_metadata *cmd,
 579                                    struct cache_disk_superblock *disk_super)
 580 {
 581         cmd->version = le32_to_cpu(disk_super->version);
 582         cmd->flags = le32_to_cpu(disk_super->flags);
 583         cmd->root = le64_to_cpu(disk_super->mapping_root);
 584         cmd->hint_root = le64_to_cpu(disk_super->hint_root);
 585         cmd->discard_root = le64_to_cpu(disk_super->discard_root);
 586         cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
 587         cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
 588         cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
 589         cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
 590         strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
 591         cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
 592         cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
 593         cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
 594         cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
 595
 596         cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
 597         cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
 598         cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
 599         cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
 600
 601         if (separate_dirty_bits(cmd))
 602                 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
 603
 604         cmd->changed = false;
 605 }
 606
 607 /*
 608  * The mutator updates the superblock flags.
 609  */
 610 static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
 611                                      flags_mutator mutator)
 612 {
 613         int r;
 614         struct cache_disk_superblock *disk_super;
 615         struct dm_block *sblock;
 616
 617         r = superblock_lock(cmd, &sblock);
 618         if (r)
 619                 return r;
 620
 621         disk_super = dm_block_data(sblock);
 622         update_flags(disk_super, mutator);
 623         read_superblock_fields(cmd, disk_super);
 624         dm_bm_unlock(sblock);
 625
 626         return dm_bm_flush(cmd->bm);
 627 }
 628
 629 static int __begin_transaction(struct dm_cache_metadata *cmd)
 630 {
 631         int r;
 632         struct cache_disk_superblock *disk_super;
 633         struct dm_block *sblock;
 634
 635         /*
 636          * We re-read the superblock every time.  Shouldn't need to do this
 637          * really.
 638          */
 639         r = superblock_read_lock(cmd, &sblock);
 640         if (r)
 641                 return r;
 642
 643         disk_super = dm_block_data(sblock);
 644         read_superblock_fields(cmd, disk_super);
 645         dm_bm_unlock(sblock);
 646
 647         return 0;
 648 }
 649
 650 static int __commit_transaction(struct dm_cache_metadata *cmd,
 651                                 flags_mutator mutator)
 652 {
 653         int r;
 654         struct cache_disk_superblock *disk_super;
 655         struct dm_block *sblock;
 656
 657         /*
 658          * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
 659          */
 660         BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
 661
 662         if (separate_dirty_bits(cmd)) {
 663                 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
 664                                     &cmd->dirty_root);
 665                 if (r)
 666                         return r;
 667         }
 668
 669         r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
 670                             &cmd->discard_root);
 671         if (r)
 672                 return r;
 673
 674         r = dm_tm_pre_commit(cmd->tm);
 675         if (r < 0)
 676                 return r;
 677
 678         r = __save_sm_root(cmd);
 679         if (r)
 680                 return r;
 681
 682         r = superblock_lock(cmd, &sblock);
 683         if (r)
 684                 return r;
 685
 686         disk_super = dm_block_data(sblock);
 687
 688         disk_super->flags = cpu_to_le32(cmd->flags);
 689         if (mutator)
 690                 update_flags(disk_super, mutator);
 691
 692         disk_super->mapping_root = cpu_to_le64(cmd->root);
 693         if (separate_dirty_bits(cmd))
 694                 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
 695         disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 696         disk_super->discard_root = cpu_to_le64(cmd->discard_root);
 697         disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
 698         disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
 699         disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
 700         strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
 701         disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
 702         disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
 703         disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
 704
 705         disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
 706         disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
 707         disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
 708         disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
 709         __copy_sm_root(cmd, disk_super);
 710
 711         return dm_tm_commit(cmd->tm, sblock);
 712 }
 713
 714 /*----------------------------------------------------------------*/
 715
 716 /*
 717  * The mappings are held in a dm-array that has 64-bit values stored in
 718  * little-endian format.  The index is the cblock, the high 48bits of the
 719  * value are the oblock and the low 16 bit the flags.
 720  */
 721 #define FLAGS_MASK ((1 << 16) - 1)
 722
 723 static __le64 pack_value(dm_oblock_t block, unsigned flags)
 724 {
 725         uint64_t value = from_oblock(block);
 726         value <<= 16;
 727         value = value | (flags & FLAGS_MASK);
 728         return cpu_to_le64(value);
 729 }
 730
 731 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
 732 {
 733         uint64_t value = le64_to_cpu(value_le);
 734         uint64_t b = value >> 16;
 735         *block = to_oblock(b);
 736         *flags = value & FLAGS_MASK;
 737 }
 738
 739 /*----------------------------------------------------------------*/
 740
 741 static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
 742                                                sector_t data_block_size,
 743                                                bool may_format_device,
 744                                                size_t policy_hint_size,
 745                                                unsigned metadata_version)
 746 {
 747         int r;
 748         struct dm_cache_metadata *cmd;
 749
 750         cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
 751         if (!cmd) {
 752                 DMERR("could not allocate metadata struct");
 753                 return ERR_PTR(-ENOMEM);
 754         }
 755
 756         cmd->version = metadata_version;
 757         refcount_set(&cmd->ref_count, 1);
 758         init_rwsem(&cmd->root_lock);
 759         cmd->bdev = bdev;
 760         cmd->data_block_size = data_block_size;
 761         cmd->cache_blocks = 0;
 762         cmd->policy_hint_size = policy_hint_size;
 763         cmd->changed = true;
 764         cmd->fail_io = false;
 765
 766         r = __create_persistent_data_objects(cmd, may_format_device);
 767         if (r) {
 768                 kfree(cmd);
 769                 return ERR_PTR(r);
 770         }
 771
 772         r = __begin_transaction_flags(cmd, clear_clean_shutdown);
 773         if (r < 0) {
 774                 dm_cache_metadata_close(cmd);
 775                 return ERR_PTR(r);
 776         }
 777
 778         return cmd;
 779 }
 780
 781 /*
 782  * We keep a little list of ref counted metadata objects to prevent two
 783  * different target instances creating separate bufio instances.  This is
 784  * an issue if a table is reloaded before the suspend.
 785  */
 786 static DEFINE_MUTEX(table_lock);
 787 static LIST_HEAD(table);
 788
 789 static struct dm_cache_metadata *lookup(struct block_device *bdev)
 790 {
 791         struct dm_cache_metadata *cmd;
 792
 793         list_for_each_entry(cmd, &table, list)
 794                 if (cmd->bdev == bdev) {
 795                         refcount_inc(&cmd->ref_count);
 796                         return cmd;
 797                 }
 798
 799         return NULL;
 800 }
 801
 802 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
 803                                                 sector_t data_block_size,
 804                                                 bool may_format_device,
 805                                                 size_t policy_hint_size,
 806                                                 unsigned metadata_version)
 807 {
 808         struct dm_cache_metadata *cmd, *cmd2;
 809
 810         mutex_lock(&table_lock);
 811         cmd = lookup(bdev);
 812         mutex_unlock(&table_lock);
 813
 814         if (cmd)
 815                 return cmd;
 816
 817         cmd = metadata_open(bdev, data_block_size, may_format_device,
 818                             policy_hint_size, metadata_version);
 819         if (!IS_ERR(cmd)) {
 820                 mutex_lock(&table_lock);
 821                 cmd2 = lookup(bdev);
 822                 if (cmd2) {
 823                         mutex_unlock(&table_lock);
 824                         __destroy_persistent_data_objects(cmd);
 825                         kfree(cmd);
 826                         return cmd2;
 827                 }
 828                 list_add(&cmd->list, &table);
 829                 mutex_unlock(&table_lock);
 830         }
 831
 832         return cmd;
 833 }
 834
 835 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
 836 {
 837         if (cmd->data_block_size != data_block_size) {
 838                 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
 839                       (unsigned long long) data_block_size,
 840                       (unsigned long long) cmd->data_block_size);
 841                 return false;
 842         }
 843
 844         return true;
 845 }
 846
 847 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
 848                                                  sector_t data_block_size,
 849                                                  bool may_format_device,
 850                                                  size_t policy_hint_size,
 851                                                  unsigned metadata_version)
 852 {
 853         struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
 854                                                        policy_hint_size, metadata_version);
 855
 856         if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
 857                 dm_cache_metadata_close(cmd);
 858                 return ERR_PTR(-EINVAL);
 859         }
 860
 861         return cmd;
 862 }
 863
 864 void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
 865 {
 866         if (refcount_dec_and_test(&cmd->ref_count)) {
 867                 mutex_lock(&table_lock);
 868                 list_del(&cmd->list);
 869                 mutex_unlock(&table_lock);
 870
 871                 if (!cmd->fail_io)
 872                         __destroy_persistent_data_objects(cmd);
 873                 kfree(cmd);
 874         }
 875 }
 876
 877 /*
 878  * Checks that the given cache block is either unmapped or clean.
 879  */
 880 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
 881                                       bool *result)
 882 {
 883         int r;
 884         __le64 value;
 885         dm_oblock_t ob;
 886         unsigned flags;
 887
 888         r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
 889         if (r)
 890                 return r;
 891
 892         unpack_value(value, &ob, &flags);
 893         *result = !((flags & M_VALID) && (flags & M_DIRTY));
 894
 895         return 0;
 896 }
 897
 898 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
 899                                            dm_cblock_t begin, dm_cblock_t end,
 900                                            bool *result)
 901 {
 902         int r;
 903         *result = true;
 904
 905         while (begin != end) {
 906                 r = block_clean_combined_dirty(cmd, begin, result);
 907                 if (r) {
 908                         DMERR("block_clean_combined_dirty failed");
 909                         return r;
 910                 }
 911
 912                 if (!*result) {
 913                         DMERR("cache block %llu is dirty",
 914                               (unsigned long long) from_cblock(begin));
 915                         return 0;
 916                 }
 917
 918                 begin = to_cblock(from_cblock(begin) + 1);
 919         }
 920
 921         return 0;
 922 }
 923
 924 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
 925                                            dm_cblock_t begin, dm_cblock_t end,
 926                                            bool *result)
 927 {
 928         int r;
 929         bool dirty_flag;
 930         *result = true;
 931
 932         r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
 933                                    from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
 934         if (r) {
 935                 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__);
 936                 return r;
 937         }
 938
 939         r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin));
 940         if (r) {
 941                 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
 942                 dm_bitset_cursor_end(&cmd->dirty_cursor);
 943                 return r;
 944         }
 945
 946         while (begin != end) {
 947                 /*
 948                  * We assume that unmapped blocks have their dirty bit
 949                  * cleared.
 950                  */
 951                 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor);
 952                 if (dirty_flag) {
 953                         DMERR("%s: cache block %llu is dirty", __func__,
 954                               (unsigned long long) from_cblock(begin));
 955                         dm_bitset_cursor_end(&cmd->dirty_cursor);
 956                         *result = false;
 957                         return 0;
 958                 }
 959
 960                 begin = to_cblock(from_cblock(begin) + 1);
 961                 if (begin == end)
 962                         break;
 963
 964                 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
 965                 if (r) {
 966                         DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
 967                         dm_bitset_cursor_end(&cmd->dirty_cursor);
 968                         return r;
 969                 }
 970         }
 971
 972         dm_bitset_cursor_end(&cmd->dirty_cursor);
 973
 974         return 0;
 975 }
 976
 977 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
 978                                         dm_cblock_t begin, dm_cblock_t end,
 979                                         bool *result)
 980 {
 981         if (separate_dirty_bits(cmd))
 982                 return blocks_are_clean_separate_dirty(cmd, begin, end, result);
 983         else
 984                 return blocks_are_clean_combined_dirty(cmd, begin, end, result);
 985 }
 986
 987 static bool cmd_write_lock(struct dm_cache_metadata *cmd)
 988 {
 989         down_write(&cmd->root_lock);
 990         if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
 991                 up_write(&cmd->root_lock);
 992                 return false;
 993         }
 994         return true;
 995 }
 996
 997 #define WRITE_LOCK(cmd)                         \
 998         do {                                    \
 999                 if (!cmd_write_lock((cmd)))     \
1000                         return -EINVAL;         \
1001         } while(0)
1002
1003 #define WRITE_LOCK_VOID(cmd)                    \
1004         do {                                    \
1005                 if (!cmd_write_lock((cmd)))     \
1006                         return;                 \
1007         } while(0)
1008
1009 #define WRITE_UNLOCK(cmd) \
1010         up_write(&(cmd)->root_lock)
1011
1012 static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1013 {
1014         down_read(&cmd->root_lock);
1015         if (cmd->fail_io) {
1016                 up_read(&cmd->root_lock);
1017                 return false;
1018         }
1019         return true;
1020 }
1021
1022 #define READ_LOCK(cmd)                          \
1023         do {                                    \
1024                 if (!cmd_read_lock((cmd)))      \
1025                         return -EINVAL;         \
1026         } while(0)
1027
1028 #define READ_LOCK_VOID(cmd)                     \
1029         do {                                    \
1030                 if (!cmd_read_lock((cmd)))      \
1031                         return;                 \
1032         } while(0)
1033
1034 #define READ_UNLOCK(cmd) \
1035         up_read(&(cmd)->root_lock)
1036
1037 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1038 {
1039         int r;
1040         bool clean;
1041         __le64 null_mapping = pack_value(0, 0);
1042
1043         WRITE_LOCK(cmd);
1044         __dm_bless_for_disk(&null_mapping);
1045
1046         if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1047                 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
1048                 if (r) {
1049                         __dm_unbless_for_disk(&null_mapping);
1050                         goto out;
1051                 }
1052
1053                 if (!clean) {
1054                         DMERR("unable to shrink cache due to dirty blocks");
1055                         r = -EINVAL;
1056                         __dm_unbless_for_disk(&null_mapping);
1057                         goto out;
1058                 }
1059         }
1060
1061         r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1062                             from_cblock(new_cache_size),
1063                             &null_mapping, &cmd->root);
1064         if (r)
1065                 goto out;
1066
1067         if (separate_dirty_bits(cmd)) {
1068                 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1069                                      from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1070                                      false, &cmd->dirty_root);
1071                 if (r)
1072                         goto out;
1073         }
1074
1075         cmd->cache_blocks = new_cache_size;
1076         cmd->changed = true;
1077
1078 out:
1079         WRITE_UNLOCK(cmd);
1080
1081         return r;
1082 }
1083
1084 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1085                                    sector_t discard_block_size,
1086                                    dm_dblock_t new_nr_entries)
1087 {
1088         int r;
1089
1090         WRITE_LOCK(cmd);
1091         r = dm_bitset_resize(&cmd->discard_info,
1092                              cmd->discard_root,
1093                              from_dblock(cmd->discard_nr_blocks),
1094                              from_dblock(new_nr_entries),
1095                              false, &cmd->discard_root);
1096         if (!r) {
1097                 cmd->discard_block_size = discard_block_size;
1098                 cmd->discard_nr_blocks = new_nr_entries;
1099         }
1100
1101         cmd->changed = true;
1102         WRITE_UNLOCK(cmd);
1103
1104         return r;
1105 }
1106
1107 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1108 {
1109         return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
1110                                  from_dblock(b), &cmd->discard_root);
1111 }
1112
1113 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1114 {
1115         return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
1116                                    from_dblock(b), &cmd->discard_root);
1117 }
1118
1119 static int __discard(struct dm_cache_metadata *cmd,
1120                      dm_dblock_t dblock, bool discard)
1121 {
1122         int r;
1123
1124         r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1125         if (r)
1126                 return r;
1127
1128         cmd->changed = true;
1129         return 0;
1130 }
1131
1132 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1133                          dm_dblock_t dblock, bool discard)
1134 {
1135         int r;
1136
1137         WRITE_LOCK(cmd);
1138         r = __discard(cmd, dblock, discard);
1139         WRITE_UNLOCK(cmd);
1140
1141         return r;
1142 }
1143
1144 static int __load_discards(struct dm_cache_metadata *cmd,
1145                            load_discard_fn fn, void *context)
1146 {
1147         int r = 0;
1148         uint32_t b;
1149         struct dm_bitset_cursor c;
1150
1151         if (from_dblock(cmd->discard_nr_blocks) == 0)
1152                 /* nothing to do */
1153                 return 0;
1154
1155         if (cmd->clean_when_opened) {
1156                 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1157                 if (r)
1158                         return r;
1159
1160                 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1161                                            from_dblock(cmd->discard_nr_blocks), &c);
1162                 if (r)
1163                         return r;
1164
1165                 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1166                         r = fn(context, cmd->discard_block_size, to_dblock(b),
1167                                dm_bitset_cursor_get_value(&c));
1168                         if (r)
1169                                 break;
1170                 }
1171
1172                 dm_bitset_cursor_end(&c);
1173
1174         } else {
1175                 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1176                         r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1177                         if (r)
1178                                 return r;
1179                 }
1180         }
1181
1182         return r;
1183 }
1184
1185 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1186                            load_discard_fn fn, void *context)
1187 {
1188         int r;
1189
1190         READ_LOCK(cmd);
1191         r = __load_discards(cmd, fn, context);
1192         READ_UNLOCK(cmd);
1193
1194         return r;
1195 }
1196
1197 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1198 {
1199         READ_LOCK(cmd);
1200         *result = cmd->cache_blocks;
1201         READ_UNLOCK(cmd);
1202
1203         return 0;
1204 }
1205
1206 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1207 {
1208         int r;
1209         __le64 value = pack_value(0, 0);
1210
1211         __dm_bless_for_disk(&value);
1212         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1213                                &value, &cmd->root);
1214         if (r)
1215                 return r;
1216
1217         cmd->changed = true;
1218         return 0;
1219 }
1220
1221 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1222 {
1223         int r;
1224
1225         WRITE_LOCK(cmd);
1226         r = __remove(cmd, cblock);
1227         WRITE_UNLOCK(cmd);
1228
1229         return r;
1230 }
1231
1232 static int __insert(struct dm_cache_metadata *cmd,
1233                     dm_cblock_t cblock, dm_oblock_t oblock)
1234 {
1235         int r;
1236         __le64 value = pack_value(oblock, M_VALID);
1237         __dm_bless_for_disk(&value);
1238
1239         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1240                                &value, &cmd->root);
1241         if (r)
1242                 return r;
1243
1244         cmd->changed = true;
1245         return 0;
1246 }
1247
1248 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1249                             dm_cblock_t cblock, dm_oblock_t oblock)
1250 {
1251         int r;
1252
1253         WRITE_LOCK(cmd);
1254         r = __insert(cmd, cblock, oblock);
1255         WRITE_UNLOCK(cmd);
1256
1257         return r;
1258 }
1259
1260 struct thunk {
1261         load_mapping_fn fn;
1262         void *context;
1263
1264         struct dm_cache_metadata *cmd;
1265         bool respect_dirty_flags;
1266         bool hints_valid;
1267 };
1268
1269 static bool policy_unchanged(struct dm_cache_metadata *cmd,
1270                              struct dm_cache_policy *policy)
1271 {
1272         const char *policy_name = dm_cache_policy_get_name(policy);
1273         const unsigned *policy_version = dm_cache_policy_get_version(policy);
1274         size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1275
1276         /*
1277          * Ensure policy names match.
1278          */
1279         if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1280                 return false;
1281
1282         /*
1283          * Ensure policy major versions match.
1284          */
1285         if (cmd->policy_version[0] != policy_version[0])
1286                 return false;
1287
1288         /*
1289          * Ensure policy hint sizes match.
1290          */
1291         if (cmd->policy_hint_size != policy_hint_size)
1292                 return false;
1293
1294         return true;
1295 }
1296
1297 static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1298 {
1299         return cmd->hint_root && cmd->policy_hint_size;
1300 }
1301
1302 static bool hints_array_available(struct dm_cache_metadata *cmd,
1303                                   struct dm_cache_policy *policy)
1304 {
1305         return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1306                 hints_array_initialized(cmd);
1307 }
1308
1309 static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1310                              uint64_t cb, bool hints_valid,
1311                              struct dm_array_cursor *mapping_cursor,
1312                              struct dm_array_cursor *hint_cursor,
1313                              load_mapping_fn fn, void *context)
1314 {
1315         int r = 0;
1316
1317         __le64 mapping;
1318         __le32 hint = 0;
1319
1320         __le64 *mapping_value_le;
1321         __le32 *hint_value_le;
1322
1323         dm_oblock_t oblock;
1324         unsigned flags;
1325
1326         dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1327         memcpy(&mapping, mapping_value_le, sizeof(mapping));
1328         unpack_value(mapping, &oblock, &flags);
1329
1330         if (flags & M_VALID) {
1331                 if (hints_valid) {
1332                         dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1333                         memcpy(&hint, hint_value_le, sizeof(hint));
1334                 }
1335
1336                 r = fn(context, oblock, to_cblock(cb), flags & M_DIRTY,
1337                        le32_to_cpu(hint), hints_valid);
1338                 if (r) {
1339                         DMERR("policy couldn't load cache block %llu",
1340                               (unsigned long long) from_cblock(to_cblock(cb)));
1341                 }
1342         }
1343
1344         return r;
1345 }
1346
1347 static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1348                              uint64_t cb, bool hints_valid,
1349                              struct dm_array_cursor *mapping_cursor,
1350                              struct dm_array_cursor *hint_cursor,
1351                              struct dm_bitset_cursor *dirty_cursor,
1352                              load_mapping_fn fn, void *context)
1353 {
1354         int r = 0;
1355
1356         __le64 mapping;
1357         __le32 hint = 0;
1358
1359         __le64 *mapping_value_le;
1360         __le32 *hint_value_le;
1361
1362         dm_oblock_t oblock;
1363         unsigned flags;
1364         bool dirty;
1365
1366         dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1367         memcpy(&mapping, mapping_value_le, sizeof(mapping));
1368         unpack_value(mapping, &oblock, &flags);
1369
1370         if (flags & M_VALID) {
1371                 if (hints_valid) {
1372                         dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1373                         memcpy(&hint, hint_value_le, sizeof(hint));
1374                 }
1375
1376                 dirty = dm_bitset_cursor_get_value(dirty_cursor);
1377                 r = fn(context, oblock, to_cblock(cb), dirty,
1378                        le32_to_cpu(hint), hints_valid);
1379                 if (r) {
1380                         DMERR("policy couldn't load cache block %llu",
1381                               (unsigned long long) from_cblock(to_cblock(cb)));
1382                 }
1383         }
1384
1385         return r;
1386 }
1387
1388 static int __load_mappings(struct dm_cache_metadata *cmd,
1389                            struct dm_cache_policy *policy,
1390                            load_mapping_fn fn, void *context)
1391 {
1392         int r;
1393         uint64_t cb;
1394
1395         bool hints_valid = hints_array_available(cmd, policy);
1396
1397         if (from_cblock(cmd->cache_blocks) == 0)
1398                 /* Nothing to do */
1399                 return 0;
1400
1401         r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1402         if (r)
1403                 return r;
1404
1405         if (hints_valid) {
1406                 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1407                 if (r) {
1408                         dm_array_cursor_end(&cmd->mapping_cursor);
1409                         return r;
1410                 }
1411         }
1412
1413         if (separate_dirty_bits(cmd)) {
1414                 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1415                                            from_cblock(cmd->cache_blocks),
1416                                            &cmd->dirty_cursor);
1417                 if (r) {
1418                         dm_array_cursor_end(&cmd->hint_cursor);
1419                         dm_array_cursor_end(&cmd->mapping_cursor);
1420                         return r;
1421                 }
1422         }
1423
1424         for (cb = 0; ; cb++) {
1425                 if (separate_dirty_bits(cmd))
1426                         r = __load_mapping_v2(cmd, cb, hints_valid,
1427                                               &cmd->mapping_cursor,
1428                                               &cmd->hint_cursor,
1429                                               &cmd->dirty_cursor,
1430                                               fn, context);
1431                 else
1432                         r = __load_mapping_v1(cmd, cb, hints_valid,
1433                                               &cmd->mapping_cursor, &cmd->hint_cursor,
1434                                               fn, context);
1435                 if (r)
1436                         goto out;
1437
1438                 /*
1439                  * We need to break out before we move the cursors.
1440                  */
1441                 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1442                         break;
1443
1444                 r = dm_array_cursor_next(&cmd->mapping_cursor);
1445                 if (r) {
1446                         DMERR("dm_array_cursor_next for mapping failed");
1447                         goto out;
1448                 }
1449
1450                 if (hints_valid) {
1451                         r = dm_array_cursor_next(&cmd->hint_cursor);
1452                         if (r) {
1453                                 DMERR("dm_array_cursor_next for hint failed");
1454                                 goto out;
1455                         }
1456                 }
1457
1458                 if (separate_dirty_bits(cmd)) {
1459                         r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1460                         if (r) {
1461                                 DMERR("dm_bitset_cursor_next for dirty failed");
1462                                 goto out;
1463                         }
1464                 }
1465         }
1466 out:
1467         dm_array_cursor_end(&cmd->mapping_cursor);
1468         if (hints_valid)
1469                 dm_array_cursor_end(&cmd->hint_cursor);
1470
1471         if (separate_dirty_bits(cmd))
1472                 dm_bitset_cursor_end(&cmd->dirty_cursor);
1473
1474         return r;
1475 }
1476
1477 int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1478                            struct dm_cache_policy *policy,
1479                            load_mapping_fn fn, void *context)
1480 {
1481         int r;
1482
1483         READ_LOCK(cmd);
1484         r = __load_mappings(cmd, policy, fn, context);
1485         READ_UNLOCK(cmd);
1486
1487         return r;
1488 }
1489
1490 static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1491 {
1492         int r = 0;
1493         __le64 value;
1494         dm_oblock_t oblock;
1495         unsigned flags;
1496
1497         memcpy(&value, leaf, sizeof(value));
1498         unpack_value(value, &oblock, &flags);
1499
1500         return r;
1501 }
1502
1503 static int __dump_mappings(struct dm_cache_metadata *cmd)
1504 {
1505         return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1506 }
1507
1508 void dm_cache_dump(struct dm_cache_metadata *cmd)
1509 {
1510         READ_LOCK_VOID(cmd);
1511         __dump_mappings(cmd);
1512         READ_UNLOCK(cmd);
1513 }
1514
1515 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1516 {
1517         int r;
1518
1519         READ_LOCK(cmd);
1520         r = cmd->changed;
1521         READ_UNLOCK(cmd);
1522
1523         return r;
1524 }
1525
1526 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1527 {
1528         int r;
1529         unsigned flags;
1530         dm_oblock_t oblock;
1531         __le64 value;
1532
1533         r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1534         if (r)
1535                 return r;
1536
1537         unpack_value(value, &oblock, &flags);
1538
1539         if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1540                 /* nothing to be done */
1541                 return 0;
1542
1543         value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1544         __dm_bless_for_disk(&value);
1545
1546         r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1547                                &value, &cmd->root);
1548         if (r)
1549                 return r;
1550
1551         cmd->changed = true;
1552         return 0;
1553
1554 }
1555
1556 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1557 {
1558         int r;
1559         unsigned i;
1560         for (i = 0; i < nr_bits; i++) {
1561                 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1562                 if (r)
1563                         return r;
1564         }
1565
1566         return 0;
1567 }
1568
1569 static int is_dirty_callback(uint32_t index, bool *value, void *context)
1570 {
1571         unsigned long *bits = context;
1572         *value = test_bit(index, bits);
1573         return 0;
1574 }
1575
1576 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1577 {
1578         int r = 0;
1579
1580         /* nr_bits is really just a sanity check */
1581         if (nr_bits != from_cblock(cmd->cache_blocks)) {
1582                 DMERR("dirty bitset is wrong size");
1583                 return -EINVAL;
1584         }
1585
1586         r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1587         if (r)
1588                 return r;
1589
1590         cmd->changed = true;
1591         return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1592 }
1593
1594 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1595                             unsigned nr_bits,
1596                             unsigned long *bits)
1597 {
1598         int r;
1599
1600         WRITE_LOCK(cmd);
1601         if (separate_dirty_bits(cmd))
1602                 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1603         else
1604                 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1605         WRITE_UNLOCK(cmd);
1606
1607         return r;
1608 }
1609
1610 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1611                                  struct dm_cache_statistics *stats)
1612 {
1613         READ_LOCK_VOID(cmd);
1614         *stats = cmd->stats;
1615         READ_UNLOCK(cmd);
1616 }
1617
1618 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1619                                  struct dm_cache_statistics *stats)
1620 {
1621         WRITE_LOCK_VOID(cmd);
1622         cmd->stats = *stats;
1623         WRITE_UNLOCK(cmd);
1624 }
1625
1626 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1627 {
1628         int r = -EINVAL;
1629         flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1630                                  clear_clean_shutdown);
1631
1632         WRITE_LOCK(cmd);
1633         if (cmd->fail_io)
1634                 goto out;
1635
1636         r = __commit_transaction(cmd, mutator);
1637         if (r)
1638                 goto out;
1639
1640         r = __begin_transaction(cmd);
1641 out:
1642         WRITE_UNLOCK(cmd);
1643         return r;
1644 }
1645
1646 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1647                                            dm_block_t *result)
1648 {
1649         int r = -EINVAL;
1650
1651         READ_LOCK(cmd);
1652         if (!cmd->fail_io)
1653                 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1654         READ_UNLOCK(cmd);
1655
1656         return r;
1657 }
1658
1659 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1660                                    dm_block_t *result)
1661 {
1662         int r = -EINVAL;
1663
1664         READ_LOCK(cmd);
1665         if (!cmd->fail_io)
1666                 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1667         READ_UNLOCK(cmd);
1668
1669         return r;
1670 }
1671
1672 /*----------------------------------------------------------------*/
1673
1674 static int get_hint(uint32_t index, void *value_le, void *context)
1675 {
1676         uint32_t value;
1677         struct dm_cache_policy *policy = context;
1678
1679         value = policy_get_hint(policy, to_cblock(index));
1680         *((__le32 *) value_le) = cpu_to_le32(value);
1681
1682         return 0;
1683 }
1684
1685 /*
1686  * It's quicker to always delete the hint array, and recreate with
1687  * dm_array_new().
1688  */
1689 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1690 {
1691         int r;
1692         size_t hint_size;
1693         const char *policy_name = dm_cache_policy_get_name(policy);
1694         const unsigned *policy_version = dm_cache_policy_get_version(policy);
1695
1696         if (!policy_name[0] ||
1697             (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1698                 return -EINVAL;
1699
1700         strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1701         memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1702
1703         hint_size = dm_cache_policy_get_hint_size(policy);
1704         if (!hint_size)
1705                 return 0; /* short-circuit hints initialization */
1706         cmd->policy_hint_size = hint_size;
1707
1708         if (cmd->hint_root) {
1709                 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1710                 if (r)
1711                         return r;
1712         }
1713
1714         return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1715                             from_cblock(cmd->cache_blocks),
1716                             get_hint, policy);
1717 }
1718
1719 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1720 {
1721         int r;
1722
1723         WRITE_LOCK(cmd);
1724         r = write_hints(cmd, policy);
1725         WRITE_UNLOCK(cmd);
1726
1727         return r;
1728 }
1729
1730 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1731 {
1732         int r;
1733
1734         READ_LOCK(cmd);
1735         r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1736         READ_UNLOCK(cmd);
1737
1738         return r;
1739 }
1740
1741 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1742 {
1743         WRITE_LOCK_VOID(cmd);
1744         dm_bm_set_read_only(cmd->bm);
1745         WRITE_UNLOCK(cmd);
1746 }
1747
1748 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1749 {
1750         WRITE_LOCK_VOID(cmd);
1751         dm_bm_set_read_write(cmd->bm);
1752         WRITE_UNLOCK(cmd);
1753 }
1754
1755 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1756 {
1757         int r;
1758         struct dm_block *sblock;
1759         struct cache_disk_superblock *disk_super;
1760
1761         WRITE_LOCK(cmd);
1762         set_bit(NEEDS_CHECK, &cmd->flags);
1763
1764         r = superblock_lock(cmd, &sblock);
1765         if (r) {
1766                 DMERR("couldn't read superblock");
1767                 goto out;
1768         }
1769
1770         disk_super = dm_block_data(sblock);
1771         disk_super->flags = cpu_to_le32(cmd->flags);
1772
1773         dm_bm_unlock(sblock);
1774
1775 out:
1776         WRITE_UNLOCK(cmd);
1777         return r;
1778 }
1779
1780 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1781 {
1782         READ_LOCK(cmd);
1783         *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1784         READ_UNLOCK(cmd);
1785
1786         return 0;
1787 }
1788
1789 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1790 {
1791         int r;
1792
1793         WRITE_LOCK(cmd);
1794         __destroy_persistent_data_objects(cmd);
1795         r = __create_persistent_data_objects(cmd, false);
1796         if (r)
1797                 cmd->fail_io = true;
1798         WRITE_UNLOCK(cmd);
1799
1800         return r;
1801 }