dm-cache-metadata.c revision c6b4fcbad044e6fffcc75bba160e720eb8d67d17
1/* 2 * Copyright (C) 2012 Red Hat, Inc. 3 * 4 * This file is released under the GPL. 5 */ 6 7#include "dm-cache-metadata.h" 8 9#include "persistent-data/dm-array.h" 10#include "persistent-data/dm-bitset.h" 11#include "persistent-data/dm-space-map.h" 12#include "persistent-data/dm-space-map-disk.h" 13#include "persistent-data/dm-transaction-manager.h" 14 15#include <linux/device-mapper.h> 16 17/*----------------------------------------------------------------*/ 18 19#define DM_MSG_PREFIX "cache metadata" 20 21#define CACHE_SUPERBLOCK_MAGIC 06142003 22#define CACHE_SUPERBLOCK_LOCATION 0 23#define CACHE_VERSION 1 24#define CACHE_METADATA_CACHE_SIZE 64 25 26/* 27 * 3 for btree insert + 28 * 2 for btree lookup used within space map 29 */ 30#define CACHE_MAX_CONCURRENT_LOCKS 5 31#define SPACE_MAP_ROOT_SIZE 128 32 33enum superblock_flag_bits { 34 /* for spotting crashes that would invalidate the dirty bitset */ 35 CLEAN_SHUTDOWN, 36}; 37 38/* 39 * Each mapping from cache block -> origin block carries a set of flags. 40 */ 41enum mapping_bits { 42 /* 43 * A valid mapping. Because we're using an array we clear this 44 * flag for an non existant mapping. 45 */ 46 M_VALID = 1, 47 48 /* 49 * The data on the cache is different from that on the origin. 50 */ 51 M_DIRTY = 2 52}; 53 54struct cache_disk_superblock { 55 __le32 csum; 56 __le32 flags; 57 __le64 blocknr; 58 59 __u8 uuid[16]; 60 __le64 magic; 61 __le32 version; 62 63 __u8 policy_name[CACHE_POLICY_NAME_SIZE]; 64 __le32 policy_hint_size; 65 66 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 67 __le64 mapping_root; 68 __le64 hint_root; 69 70 __le64 discard_root; 71 __le64 discard_block_size; 72 __le64 discard_nr_blocks; 73 74 __le32 data_block_size; 75 __le32 metadata_block_size; 76 __le32 cache_blocks; 77 78 __le32 compat_flags; 79 __le32 compat_ro_flags; 80 __le32 incompat_flags; 81 82 __le32 read_hits; 83 __le32 read_misses; 84 __le32 write_hits; 85 __le32 write_misses; 86} __packed; 87 88struct dm_cache_metadata { 89 struct block_device *bdev; 90 struct dm_block_manager *bm; 91 struct dm_space_map *metadata_sm; 92 struct dm_transaction_manager *tm; 93 94 struct dm_array_info info; 95 struct dm_array_info hint_info; 96 struct dm_disk_bitset discard_info; 97 98 struct rw_semaphore root_lock; 99 dm_block_t root; 100 dm_block_t hint_root; 101 dm_block_t discard_root; 102 103 sector_t discard_block_size; 104 dm_dblock_t discard_nr_blocks; 105 106 sector_t data_block_size; 107 dm_cblock_t cache_blocks; 108 bool changed:1; 109 bool clean_when_opened:1; 110 111 char policy_name[CACHE_POLICY_NAME_SIZE]; 112 size_t policy_hint_size; 113 struct dm_cache_statistics stats; 114}; 115 116/*------------------------------------------------------------------- 117 * superblock validator 118 *-----------------------------------------------------------------*/ 119 120#define SUPERBLOCK_CSUM_XOR 9031977 121 122static void sb_prepare_for_write(struct dm_block_validator *v, 123 struct dm_block *b, 124 size_t sb_block_size) 125{ 126 struct cache_disk_superblock *disk_super = dm_block_data(b); 127 128 disk_super->blocknr = cpu_to_le64(dm_block_location(b)); 129 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 130 sb_block_size - sizeof(__le32), 131 SUPERBLOCK_CSUM_XOR)); 132} 133 134static int sb_check(struct dm_block_validator *v, 135 struct dm_block *b, 136 size_t sb_block_size) 137{ 138 struct cache_disk_superblock *disk_super = dm_block_data(b); 139 __le32 csum_le; 140 141 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { 142 DMERR("sb_check failed: blocknr %llu: wanted %llu", 143 le64_to_cpu(disk_super->blocknr), 144 (unsigned long long)dm_block_location(b)); 145 return -ENOTBLK; 146 } 147 148 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { 149 DMERR("sb_check failed: magic %llu: wanted %llu", 150 le64_to_cpu(disk_super->magic), 151 (unsigned long long)CACHE_SUPERBLOCK_MAGIC); 152 return -EILSEQ; 153 } 154 155 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 156 sb_block_size - sizeof(__le32), 157 SUPERBLOCK_CSUM_XOR)); 158 if (csum_le != disk_super->csum) { 159 DMERR("sb_check failed: csum %u: wanted %u", 160 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); 161 return -EILSEQ; 162 } 163 164 return 0; 165} 166 167static struct dm_block_validator sb_validator = { 168 .name = "superblock", 169 .prepare_for_write = sb_prepare_for_write, 170 .check = sb_check 171}; 172 173/*----------------------------------------------------------------*/ 174 175static int superblock_read_lock(struct dm_cache_metadata *cmd, 176 struct dm_block **sblock) 177{ 178 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 179 &sb_validator, sblock); 180} 181 182static int superblock_lock_zero(struct dm_cache_metadata *cmd, 183 struct dm_block **sblock) 184{ 185 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 186 &sb_validator, sblock); 187} 188 189static int superblock_lock(struct dm_cache_metadata *cmd, 190 struct dm_block **sblock) 191{ 192 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 193 &sb_validator, sblock); 194} 195 196/*----------------------------------------------------------------*/ 197 198static int __superblock_all_zeroes(struct dm_block_manager *bm, int *result) 199{ 200 int r; 201 unsigned i; 202 struct dm_block *b; 203 __le64 *data_le, zero = cpu_to_le64(0); 204 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 205 206 /* 207 * We can't use a validator here - it may be all zeroes. 208 */ 209 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); 210 if (r) 211 return r; 212 213 data_le = dm_block_data(b); 214 *result = 1; 215 for (i = 0; i < sb_block_size; i++) { 216 if (data_le[i] != zero) { 217 *result = 0; 218 break; 219 } 220 } 221 222 return dm_bm_unlock(b); 223} 224 225static void __setup_mapping_info(struct dm_cache_metadata *cmd) 226{ 227 struct dm_btree_value_type vt; 228 229 vt.context = NULL; 230 vt.size = sizeof(__le64); 231 vt.inc = NULL; 232 vt.dec = NULL; 233 vt.equal = NULL; 234 dm_array_info_init(&cmd->info, cmd->tm, &vt); 235 236 if (cmd->policy_hint_size) { 237 vt.size = sizeof(__le32); 238 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); 239 } 240} 241 242static int __write_initial_superblock(struct dm_cache_metadata *cmd) 243{ 244 int r; 245 struct dm_block *sblock; 246 size_t metadata_len; 247 struct cache_disk_superblock *disk_super; 248 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT; 249 250 /* FIXME: see if we can lose the max sectors limit */ 251 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) 252 bdev_size = DM_CACHE_METADATA_MAX_SECTORS; 253 254 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 255 if (r < 0) 256 return r; 257 258 r = dm_tm_pre_commit(cmd->tm); 259 if (r < 0) 260 return r; 261 262 r = superblock_lock_zero(cmd, &sblock); 263 if (r) 264 return r; 265 266 disk_super = dm_block_data(sblock); 267 disk_super->flags = 0; 268 memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); 269 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); 270 disk_super->version = cpu_to_le32(CACHE_VERSION); 271 memset(disk_super->policy_name, 0, CACHE_POLICY_NAME_SIZE); 272 disk_super->policy_hint_size = 0; 273 274 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, 275 metadata_len); 276 if (r < 0) 277 goto bad_locked; 278 279 disk_super->mapping_root = cpu_to_le64(cmd->root); 280 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 281 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 282 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 283 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 284 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); 285 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); 286 disk_super->cache_blocks = cpu_to_le32(0); 287 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); 288 289 disk_super->read_hits = cpu_to_le32(0); 290 disk_super->read_misses = cpu_to_le32(0); 291 disk_super->write_hits = cpu_to_le32(0); 292 disk_super->write_misses = cpu_to_le32(0); 293 294 return dm_tm_commit(cmd->tm, sblock); 295 296bad_locked: 297 dm_bm_unlock(sblock); 298 return r; 299} 300 301static int __format_metadata(struct dm_cache_metadata *cmd) 302{ 303 int r; 304 305 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 306 &cmd->tm, &cmd->metadata_sm); 307 if (r < 0) { 308 DMERR("tm_create_with_sm failed"); 309 return r; 310 } 311 312 __setup_mapping_info(cmd); 313 314 r = dm_array_empty(&cmd->info, &cmd->root); 315 if (r < 0) 316 goto bad; 317 318 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 319 320 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); 321 if (r < 0) 322 goto bad; 323 324 cmd->discard_block_size = 0; 325 cmd->discard_nr_blocks = 0; 326 327 r = __write_initial_superblock(cmd); 328 if (r) 329 goto bad; 330 331 cmd->clean_when_opened = true; 332 return 0; 333 334bad: 335 dm_tm_destroy(cmd->tm); 336 dm_sm_destroy(cmd->metadata_sm); 337 338 return r; 339} 340 341static int __check_incompat_features(struct cache_disk_superblock *disk_super, 342 struct dm_cache_metadata *cmd) 343{ 344 uint32_t features; 345 346 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; 347 if (features) { 348 DMERR("could not access metadata due to unsupported optional features (%lx).", 349 (unsigned long)features); 350 return -EINVAL; 351 } 352 353 /* 354 * Check for read-only metadata to skip the following RDWR checks. 355 */ 356 if (get_disk_ro(cmd->bdev->bd_disk)) 357 return 0; 358 359 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; 360 if (features) { 361 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", 362 (unsigned long)features); 363 return -EINVAL; 364 } 365 366 return 0; 367} 368 369static int __open_metadata(struct dm_cache_metadata *cmd) 370{ 371 int r; 372 struct dm_block *sblock; 373 struct cache_disk_superblock *disk_super; 374 unsigned long sb_flags; 375 376 r = superblock_read_lock(cmd, &sblock); 377 if (r < 0) { 378 DMERR("couldn't read lock superblock"); 379 return r; 380 } 381 382 disk_super = dm_block_data(sblock); 383 384 r = __check_incompat_features(disk_super, cmd); 385 if (r < 0) 386 goto bad; 387 388 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 389 disk_super->metadata_space_map_root, 390 sizeof(disk_super->metadata_space_map_root), 391 &cmd->tm, &cmd->metadata_sm); 392 if (r < 0) { 393 DMERR("tm_open_with_sm failed"); 394 goto bad; 395 } 396 397 __setup_mapping_info(cmd); 398 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 399 sb_flags = le32_to_cpu(disk_super->flags); 400 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); 401 return dm_bm_unlock(sblock); 402 403bad: 404 dm_bm_unlock(sblock); 405 return r; 406} 407 408static int __open_or_format_metadata(struct dm_cache_metadata *cmd, 409 bool format_device) 410{ 411 int r, unformatted; 412 413 r = __superblock_all_zeroes(cmd->bm, &unformatted); 414 if (r) 415 return r; 416 417 if (unformatted) 418 return format_device ? __format_metadata(cmd) : -EPERM; 419 420 return __open_metadata(cmd); 421} 422 423static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, 424 bool may_format_device) 425{ 426 int r; 427 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE, 428 CACHE_METADATA_CACHE_SIZE, 429 CACHE_MAX_CONCURRENT_LOCKS); 430 if (IS_ERR(cmd->bm)) { 431 DMERR("could not create block manager"); 432 return PTR_ERR(cmd->bm); 433 } 434 435 r = __open_or_format_metadata(cmd, may_format_device); 436 if (r) 437 dm_block_manager_destroy(cmd->bm); 438 439 return r; 440} 441 442static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) 443{ 444 dm_sm_destroy(cmd->metadata_sm); 445 dm_tm_destroy(cmd->tm); 446 dm_block_manager_destroy(cmd->bm); 447} 448 449typedef unsigned long (*flags_mutator)(unsigned long); 450 451static void update_flags(struct cache_disk_superblock *disk_super, 452 flags_mutator mutator) 453{ 454 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); 455 disk_super->flags = cpu_to_le32(sb_flags); 456} 457 458static unsigned long set_clean_shutdown(unsigned long flags) 459{ 460 set_bit(CLEAN_SHUTDOWN, &flags); 461 return flags; 462} 463 464static unsigned long clear_clean_shutdown(unsigned long flags) 465{ 466 clear_bit(CLEAN_SHUTDOWN, &flags); 467 return flags; 468} 469 470static void read_superblock_fields(struct dm_cache_metadata *cmd, 471 struct cache_disk_superblock *disk_super) 472{ 473 cmd->root = le64_to_cpu(disk_super->mapping_root); 474 cmd->hint_root = le64_to_cpu(disk_super->hint_root); 475 cmd->discard_root = le64_to_cpu(disk_super->discard_root); 476 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); 477 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); 478 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); 479 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); 480 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); 481 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); 482 483 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); 484 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); 485 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); 486 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); 487 488 cmd->changed = false; 489} 490 491/* 492 * The mutator updates the superblock flags. 493 */ 494static int __begin_transaction_flags(struct dm_cache_metadata *cmd, 495 flags_mutator mutator) 496{ 497 int r; 498 struct cache_disk_superblock *disk_super; 499 struct dm_block *sblock; 500 501 r = superblock_lock(cmd, &sblock); 502 if (r) 503 return r; 504 505 disk_super = dm_block_data(sblock); 506 update_flags(disk_super, mutator); 507 read_superblock_fields(cmd, disk_super); 508 509 return dm_bm_flush_and_unlock(cmd->bm, sblock); 510} 511 512static int __begin_transaction(struct dm_cache_metadata *cmd) 513{ 514 int r; 515 struct cache_disk_superblock *disk_super; 516 struct dm_block *sblock; 517 518 /* 519 * We re-read the superblock every time. Shouldn't need to do this 520 * really. 521 */ 522 r = superblock_read_lock(cmd, &sblock); 523 if (r) 524 return r; 525 526 disk_super = dm_block_data(sblock); 527 read_superblock_fields(cmd, disk_super); 528 dm_bm_unlock(sblock); 529 530 return 0; 531} 532 533static int __commit_transaction(struct dm_cache_metadata *cmd, 534 flags_mutator mutator) 535{ 536 int r; 537 size_t metadata_len; 538 struct cache_disk_superblock *disk_super; 539 struct dm_block *sblock; 540 541 /* 542 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 543 */ 544 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 545 546 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 547 &cmd->discard_root); 548 if (r) 549 return r; 550 551 r = dm_tm_pre_commit(cmd->tm); 552 if (r < 0) 553 return r; 554 555 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 556 if (r < 0) 557 return r; 558 559 r = superblock_lock(cmd, &sblock); 560 if (r) 561 return r; 562 563 disk_super = dm_block_data(sblock); 564 565 if (mutator) 566 update_flags(disk_super, mutator); 567 568 disk_super->mapping_root = cpu_to_le64(cmd->root); 569 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 570 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 571 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 572 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 573 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 574 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 575 576 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 577 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 578 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 579 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 580 581 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, 582 metadata_len); 583 if (r < 0) { 584 dm_bm_unlock(sblock); 585 return r; 586 } 587 588 return dm_tm_commit(cmd->tm, sblock); 589} 590 591/*----------------------------------------------------------------*/ 592 593/* 594 * The mappings are held in a dm-array that has 64-bit values stored in 595 * little-endian format. The index is the cblock, the high 48bits of the 596 * value are the oblock and the low 16 bit the flags. 597 */ 598#define FLAGS_MASK ((1 << 16) - 1) 599 600static __le64 pack_value(dm_oblock_t block, unsigned flags) 601{ 602 uint64_t value = from_oblock(block); 603 value <<= 16; 604 value = value | (flags & FLAGS_MASK); 605 return cpu_to_le64(value); 606} 607 608static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 609{ 610 uint64_t value = le64_to_cpu(value_le); 611 uint64_t b = value >> 16; 612 *block = to_oblock(b); 613 *flags = value & FLAGS_MASK; 614} 615 616/*----------------------------------------------------------------*/ 617 618struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 619 sector_t data_block_size, 620 bool may_format_device, 621 size_t policy_hint_size) 622{ 623 int r; 624 struct dm_cache_metadata *cmd; 625 626 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 627 if (!cmd) { 628 DMERR("could not allocate metadata struct"); 629 return NULL; 630 } 631 632 init_rwsem(&cmd->root_lock); 633 cmd->bdev = bdev; 634 cmd->data_block_size = data_block_size; 635 cmd->cache_blocks = 0; 636 cmd->policy_hint_size = policy_hint_size; 637 cmd->changed = true; 638 639 r = __create_persistent_data_objects(cmd, may_format_device); 640 if (r) { 641 kfree(cmd); 642 return ERR_PTR(r); 643 } 644 645 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 646 if (r < 0) { 647 dm_cache_metadata_close(cmd); 648 return ERR_PTR(r); 649 } 650 651 return cmd; 652} 653 654void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 655{ 656 __destroy_persistent_data_objects(cmd); 657 kfree(cmd); 658} 659 660int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) 661{ 662 int r; 663 __le64 null_mapping = pack_value(0, 0); 664 665 down_write(&cmd->root_lock); 666 __dm_bless_for_disk(&null_mapping); 667 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), 668 from_cblock(new_cache_size), 669 &null_mapping, &cmd->root); 670 if (!r) 671 cmd->cache_blocks = new_cache_size; 672 cmd->changed = true; 673 up_write(&cmd->root_lock); 674 675 return r; 676} 677 678int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 679 sector_t discard_block_size, 680 dm_dblock_t new_nr_entries) 681{ 682 int r; 683 684 down_write(&cmd->root_lock); 685 r = dm_bitset_resize(&cmd->discard_info, 686 cmd->discard_root, 687 from_dblock(cmd->discard_nr_blocks), 688 from_dblock(new_nr_entries), 689 false, &cmd->discard_root); 690 if (!r) { 691 cmd->discard_block_size = discard_block_size; 692 cmd->discard_nr_blocks = new_nr_entries; 693 } 694 695 cmd->changed = true; 696 up_write(&cmd->root_lock); 697 698 return r; 699} 700 701static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 702{ 703 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, 704 from_dblock(b), &cmd->discard_root); 705} 706 707static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 708{ 709 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, 710 from_dblock(b), &cmd->discard_root); 711} 712 713static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b, 714 bool *is_discarded) 715{ 716 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root, 717 from_dblock(b), &cmd->discard_root, 718 is_discarded); 719} 720 721static int __discard(struct dm_cache_metadata *cmd, 722 dm_dblock_t dblock, bool discard) 723{ 724 int r; 725 726 r = (discard ? __set_discard : __clear_discard)(cmd, dblock); 727 if (r) 728 return r; 729 730 cmd->changed = true; 731 return 0; 732} 733 734int dm_cache_set_discard(struct dm_cache_metadata *cmd, 735 dm_dblock_t dblock, bool discard) 736{ 737 int r; 738 739 down_write(&cmd->root_lock); 740 r = __discard(cmd, dblock, discard); 741 up_write(&cmd->root_lock); 742 743 return r; 744} 745 746static int __load_discards(struct dm_cache_metadata *cmd, 747 load_discard_fn fn, void *context) 748{ 749 int r = 0; 750 dm_block_t b; 751 bool discard; 752 753 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { 754 dm_dblock_t dblock = to_dblock(b); 755 756 if (cmd->clean_when_opened) { 757 r = __is_discarded(cmd, dblock, &discard); 758 if (r) 759 return r; 760 } else 761 discard = false; 762 763 r = fn(context, cmd->discard_block_size, dblock, discard); 764 if (r) 765 break; 766 } 767 768 return r; 769} 770 771int dm_cache_load_discards(struct dm_cache_metadata *cmd, 772 load_discard_fn fn, void *context) 773{ 774 int r; 775 776 down_read(&cmd->root_lock); 777 r = __load_discards(cmd, fn, context); 778 up_read(&cmd->root_lock); 779 780 return r; 781} 782 783dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd) 784{ 785 dm_cblock_t r; 786 787 down_read(&cmd->root_lock); 788 r = cmd->cache_blocks; 789 up_read(&cmd->root_lock); 790 791 return r; 792} 793 794static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 795{ 796 int r; 797 __le64 value = pack_value(0, 0); 798 799 __dm_bless_for_disk(&value); 800 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 801 &value, &cmd->root); 802 if (r) 803 return r; 804 805 cmd->changed = true; 806 return 0; 807} 808 809int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 810{ 811 int r; 812 813 down_write(&cmd->root_lock); 814 r = __remove(cmd, cblock); 815 up_write(&cmd->root_lock); 816 817 return r; 818} 819 820static int __insert(struct dm_cache_metadata *cmd, 821 dm_cblock_t cblock, dm_oblock_t oblock) 822{ 823 int r; 824 __le64 value = pack_value(oblock, M_VALID); 825 __dm_bless_for_disk(&value); 826 827 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 828 &value, &cmd->root); 829 if (r) 830 return r; 831 832 cmd->changed = true; 833 return 0; 834} 835 836int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, 837 dm_cblock_t cblock, dm_oblock_t oblock) 838{ 839 int r; 840 841 down_write(&cmd->root_lock); 842 r = __insert(cmd, cblock, oblock); 843 up_write(&cmd->root_lock); 844 845 return r; 846} 847 848struct thunk { 849 load_mapping_fn fn; 850 void *context; 851 852 struct dm_cache_metadata *cmd; 853 bool respect_dirty_flags; 854 bool hints_valid; 855}; 856 857static bool hints_array_initialized(struct dm_cache_metadata *cmd) 858{ 859 return cmd->hint_root && cmd->policy_hint_size; 860} 861 862static bool hints_array_available(struct dm_cache_metadata *cmd, 863 const char *policy_name) 864{ 865 bool policy_names_match = !strncmp(cmd->policy_name, policy_name, 866 sizeof(cmd->policy_name)); 867 868 return cmd->clean_when_opened && policy_names_match && 869 hints_array_initialized(cmd); 870} 871 872static int __load_mapping(void *context, uint64_t cblock, void *leaf) 873{ 874 int r = 0; 875 bool dirty; 876 __le64 value; 877 __le32 hint_value = 0; 878 dm_oblock_t oblock; 879 unsigned flags; 880 struct thunk *thunk = context; 881 struct dm_cache_metadata *cmd = thunk->cmd; 882 883 memcpy(&value, leaf, sizeof(value)); 884 unpack_value(value, &oblock, &flags); 885 886 if (flags & M_VALID) { 887 if (thunk->hints_valid) { 888 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root, 889 cblock, &hint_value); 890 if (r && r != -ENODATA) 891 return r; 892 } 893 894 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true; 895 r = thunk->fn(thunk->context, oblock, to_cblock(cblock), 896 dirty, le32_to_cpu(hint_value), thunk->hints_valid); 897 } 898 899 return r; 900} 901 902static int __load_mappings(struct dm_cache_metadata *cmd, const char *policy_name, 903 load_mapping_fn fn, void *context) 904{ 905 struct thunk thunk; 906 907 thunk.fn = fn; 908 thunk.context = context; 909 910 thunk.cmd = cmd; 911 thunk.respect_dirty_flags = cmd->clean_when_opened; 912 thunk.hints_valid = hints_array_available(cmd, policy_name); 913 914 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk); 915} 916 917int dm_cache_load_mappings(struct dm_cache_metadata *cmd, const char *policy_name, 918 load_mapping_fn fn, void *context) 919{ 920 int r; 921 922 down_read(&cmd->root_lock); 923 r = __load_mappings(cmd, policy_name, fn, context); 924 up_read(&cmd->root_lock); 925 926 return r; 927} 928 929static int __dump_mapping(void *context, uint64_t cblock, void *leaf) 930{ 931 int r = 0; 932 __le64 value; 933 dm_oblock_t oblock; 934 unsigned flags; 935 936 memcpy(&value, leaf, sizeof(value)); 937 unpack_value(value, &oblock, &flags); 938 939 return r; 940} 941 942static int __dump_mappings(struct dm_cache_metadata *cmd) 943{ 944 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); 945} 946 947void dm_cache_dump(struct dm_cache_metadata *cmd) 948{ 949 down_read(&cmd->root_lock); 950 __dump_mappings(cmd); 951 up_read(&cmd->root_lock); 952} 953 954int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) 955{ 956 int r; 957 958 down_read(&cmd->root_lock); 959 r = cmd->changed; 960 up_read(&cmd->root_lock); 961 962 return r; 963} 964 965static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) 966{ 967 int r; 968 unsigned flags; 969 dm_oblock_t oblock; 970 __le64 value; 971 972 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); 973 if (r) 974 return r; 975 976 unpack_value(value, &oblock, &flags); 977 978 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) 979 /* nothing to be done */ 980 return 0; 981 982 value = pack_value(oblock, flags | (dirty ? M_DIRTY : 0)); 983 __dm_bless_for_disk(&value); 984 985 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 986 &value, &cmd->root); 987 if (r) 988 return r; 989 990 cmd->changed = true; 991 return 0; 992 993} 994 995int dm_cache_set_dirty(struct dm_cache_metadata *cmd, 996 dm_cblock_t cblock, bool dirty) 997{ 998 int r; 999 1000 down_write(&cmd->root_lock); 1001 r = __dirty(cmd, cblock, dirty); 1002 up_write(&cmd->root_lock); 1003 1004 return r; 1005} 1006 1007void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 1008 struct dm_cache_statistics *stats) 1009{ 1010 down_read(&cmd->root_lock); 1011 memcpy(stats, &cmd->stats, sizeof(*stats)); 1012 up_read(&cmd->root_lock); 1013} 1014 1015void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 1016 struct dm_cache_statistics *stats) 1017{ 1018 down_write(&cmd->root_lock); 1019 memcpy(&cmd->stats, stats, sizeof(*stats)); 1020 up_write(&cmd->root_lock); 1021} 1022 1023int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) 1024{ 1025 int r; 1026 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1027 clear_clean_shutdown); 1028 1029 down_write(&cmd->root_lock); 1030 r = __commit_transaction(cmd, mutator); 1031 if (r) 1032 goto out; 1033 1034 r = __begin_transaction(cmd); 1035 1036out: 1037 up_write(&cmd->root_lock); 1038 return r; 1039} 1040 1041int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1042 dm_block_t *result) 1043{ 1044 int r = -EINVAL; 1045 1046 down_read(&cmd->root_lock); 1047 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1048 up_read(&cmd->root_lock); 1049 1050 return r; 1051} 1052 1053int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1054 dm_block_t *result) 1055{ 1056 int r = -EINVAL; 1057 1058 down_read(&cmd->root_lock); 1059 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1060 up_read(&cmd->root_lock); 1061 1062 return r; 1063} 1064 1065/*----------------------------------------------------------------*/ 1066 1067static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1068{ 1069 int r; 1070 __le32 value; 1071 size_t hint_size; 1072 const char *policy_name = dm_cache_policy_get_name(policy); 1073 1074 if (!policy_name[0] || 1075 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1076 return -EINVAL; 1077 1078 if (strcmp(cmd->policy_name, policy_name)) { 1079 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1080 1081 hint_size = dm_cache_policy_get_hint_size(policy); 1082 if (!hint_size) 1083 return 0; /* short-circuit hints initialization */ 1084 cmd->policy_hint_size = hint_size; 1085 1086 if (cmd->hint_root) { 1087 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1088 if (r) 1089 return r; 1090 } 1091 1092 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root); 1093 if (r) 1094 return r; 1095 1096 value = cpu_to_le32(0); 1097 __dm_bless_for_disk(&value); 1098 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0, 1099 from_cblock(cmd->cache_blocks), 1100 &value, &cmd->hint_root); 1101 if (r) 1102 return r; 1103 } 1104 1105 return 0; 1106} 1107 1108int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1109{ 1110 int r; 1111 1112 down_write(&cmd->root_lock); 1113 r = begin_hints(cmd, policy); 1114 up_write(&cmd->root_lock); 1115 1116 return r; 1117} 1118 1119static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, 1120 uint32_t hint) 1121{ 1122 int r; 1123 __le32 value = cpu_to_le32(hint); 1124 __dm_bless_for_disk(&value); 1125 1126 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root, 1127 from_cblock(cblock), &value, &cmd->hint_root); 1128 cmd->changed = true; 1129 1130 return r; 1131} 1132 1133int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, 1134 uint32_t hint) 1135{ 1136 int r; 1137 1138 if (!hints_array_initialized(cmd)) 1139 return 0; 1140 1141 down_write(&cmd->root_lock); 1142 r = save_hint(cmd, cblock, hint); 1143 up_write(&cmd->root_lock); 1144 1145 return r; 1146} 1147