dm-cache-metadata.c revision a9d45396f5956d0b615c7ae3b936afd888351a47
1/* 2 * Copyright (C) 2012 Red Hat, Inc. 3 * 4 * This file is released under the GPL. 5 */ 6 7#include "dm-cache-metadata.h" 8 9#include "persistent-data/dm-array.h" 10#include "persistent-data/dm-bitset.h" 11#include "persistent-data/dm-space-map.h" 12#include "persistent-data/dm-space-map-disk.h" 13#include "persistent-data/dm-transaction-manager.h" 14 15#include <linux/device-mapper.h> 16 17/*----------------------------------------------------------------*/ 18 19#define DM_MSG_PREFIX "cache metadata" 20 21#define CACHE_SUPERBLOCK_MAGIC 06142003 22#define CACHE_SUPERBLOCK_LOCATION 0 23 24/* 25 * defines a range of metadata versions that this module can handle. 26 */ 27#define MIN_CACHE_VERSION 1 28#define MAX_CACHE_VERSION 1 29 30#define CACHE_METADATA_CACHE_SIZE 64 31 32/* 33 * 3 for btree insert + 34 * 2 for btree lookup used within space map 35 */ 36#define CACHE_MAX_CONCURRENT_LOCKS 5 37#define SPACE_MAP_ROOT_SIZE 128 38 39enum superblock_flag_bits { 40 /* for spotting crashes that would invalidate the dirty bitset */ 41 CLEAN_SHUTDOWN, 42}; 43 44/* 45 * Each mapping from cache block -> origin block carries a set of flags. 46 */ 47enum mapping_bits { 48 /* 49 * A valid mapping. Because we're using an array we clear this 50 * flag for an non existant mapping. 51 */ 52 M_VALID = 1, 53 54 /* 55 * The data on the cache is different from that on the origin. 56 */ 57 M_DIRTY = 2 58}; 59 60struct cache_disk_superblock { 61 __le32 csum; 62 __le32 flags; 63 __le64 blocknr; 64 65 __u8 uuid[16]; 66 __le64 magic; 67 __le32 version; 68 69 __u8 policy_name[CACHE_POLICY_NAME_SIZE]; 70 __le32 policy_hint_size; 71 72 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 73 __le64 mapping_root; 74 __le64 hint_root; 75 76 __le64 discard_root; 77 __le64 discard_block_size; 78 __le64 discard_nr_blocks; 79 80 __le32 data_block_size; 81 __le32 metadata_block_size; 82 __le32 cache_blocks; 83 84 __le32 compat_flags; 85 __le32 compat_ro_flags; 86 __le32 incompat_flags; 87 88 __le32 read_hits; 89 __le32 read_misses; 90 __le32 write_hits; 91 __le32 write_misses; 92 93 __le32 policy_version[CACHE_POLICY_VERSION_SIZE]; 94} __packed; 95 96struct dm_cache_metadata { 97 struct block_device *bdev; 98 struct dm_block_manager *bm; 99 struct dm_space_map *metadata_sm; 100 struct dm_transaction_manager *tm; 101 102 struct dm_array_info info; 103 struct dm_array_info hint_info; 104 struct dm_disk_bitset discard_info; 105 106 struct rw_semaphore root_lock; 107 dm_block_t root; 108 dm_block_t hint_root; 109 dm_block_t discard_root; 110 111 sector_t discard_block_size; 112 dm_oblock_t discard_nr_blocks; 113 114 sector_t data_block_size; 115 dm_cblock_t cache_blocks; 116 bool changed:1; 117 bool clean_when_opened:1; 118 119 char policy_name[CACHE_POLICY_NAME_SIZE]; 120 unsigned policy_version[CACHE_POLICY_VERSION_SIZE]; 121 size_t policy_hint_size; 122 struct dm_cache_statistics stats; 123}; 124 125/*------------------------------------------------------------------- 126 * superblock validator 127 *-----------------------------------------------------------------*/ 128 129#define SUPERBLOCK_CSUM_XOR 9031977 130 131static void sb_prepare_for_write(struct dm_block_validator *v, 132 struct dm_block *b, 133 size_t sb_block_size) 134{ 135 struct cache_disk_superblock *disk_super = dm_block_data(b); 136 137 disk_super->blocknr = cpu_to_le64(dm_block_location(b)); 138 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 139 sb_block_size - sizeof(__le32), 140 SUPERBLOCK_CSUM_XOR)); 141} 142 143static int check_metadata_version(struct cache_disk_superblock *disk_super) 144{ 145 uint32_t metadata_version = le32_to_cpu(disk_super->version); 146 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) { 147 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.", 148 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION); 149 return -EINVAL; 150 } 151 152 return 0; 153} 154 155static int sb_check(struct dm_block_validator *v, 156 struct dm_block *b, 157 size_t sb_block_size) 158{ 159 struct cache_disk_superblock *disk_super = dm_block_data(b); 160 __le32 csum_le; 161 162 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { 163 DMERR("sb_check failed: blocknr %llu: wanted %llu", 164 le64_to_cpu(disk_super->blocknr), 165 (unsigned long long)dm_block_location(b)); 166 return -ENOTBLK; 167 } 168 169 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { 170 DMERR("sb_check failed: magic %llu: wanted %llu", 171 le64_to_cpu(disk_super->magic), 172 (unsigned long long)CACHE_SUPERBLOCK_MAGIC); 173 return -EILSEQ; 174 } 175 176 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 177 sb_block_size - sizeof(__le32), 178 SUPERBLOCK_CSUM_XOR)); 179 if (csum_le != disk_super->csum) { 180 DMERR("sb_check failed: csum %u: wanted %u", 181 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); 182 return -EILSEQ; 183 } 184 185 return check_metadata_version(disk_super); 186} 187 188static struct dm_block_validator sb_validator = { 189 .name = "superblock", 190 .prepare_for_write = sb_prepare_for_write, 191 .check = sb_check 192}; 193 194/*----------------------------------------------------------------*/ 195 196static int superblock_read_lock(struct dm_cache_metadata *cmd, 197 struct dm_block **sblock) 198{ 199 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 200 &sb_validator, sblock); 201} 202 203static int superblock_lock_zero(struct dm_cache_metadata *cmd, 204 struct dm_block **sblock) 205{ 206 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 207 &sb_validator, sblock); 208} 209 210static int superblock_lock(struct dm_cache_metadata *cmd, 211 struct dm_block **sblock) 212{ 213 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 214 &sb_validator, sblock); 215} 216 217/*----------------------------------------------------------------*/ 218 219static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result) 220{ 221 int r; 222 unsigned i; 223 struct dm_block *b; 224 __le64 *data_le, zero = cpu_to_le64(0); 225 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 226 227 /* 228 * We can't use a validator here - it may be all zeroes. 229 */ 230 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); 231 if (r) 232 return r; 233 234 data_le = dm_block_data(b); 235 *result = true; 236 for (i = 0; i < sb_block_size; i++) { 237 if (data_le[i] != zero) { 238 *result = false; 239 break; 240 } 241 } 242 243 return dm_bm_unlock(b); 244} 245 246static void __setup_mapping_info(struct dm_cache_metadata *cmd) 247{ 248 struct dm_btree_value_type vt; 249 250 vt.context = NULL; 251 vt.size = sizeof(__le64); 252 vt.inc = NULL; 253 vt.dec = NULL; 254 vt.equal = NULL; 255 dm_array_info_init(&cmd->info, cmd->tm, &vt); 256 257 if (cmd->policy_hint_size) { 258 vt.size = sizeof(__le32); 259 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); 260 } 261} 262 263static int __write_initial_superblock(struct dm_cache_metadata *cmd) 264{ 265 int r; 266 struct dm_block *sblock; 267 size_t metadata_len; 268 struct cache_disk_superblock *disk_super; 269 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT; 270 271 /* FIXME: see if we can lose the max sectors limit */ 272 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) 273 bdev_size = DM_CACHE_METADATA_MAX_SECTORS; 274 275 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 276 if (r < 0) 277 return r; 278 279 r = dm_tm_pre_commit(cmd->tm); 280 if (r < 0) 281 return r; 282 283 r = superblock_lock_zero(cmd, &sblock); 284 if (r) 285 return r; 286 287 disk_super = dm_block_data(sblock); 288 disk_super->flags = 0; 289 memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); 290 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); 291 disk_super->version = cpu_to_le32(MAX_CACHE_VERSION); 292 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); 293 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); 294 disk_super->policy_hint_size = 0; 295 296 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, 297 metadata_len); 298 if (r < 0) 299 goto bad_locked; 300 301 disk_super->mapping_root = cpu_to_le64(cmd->root); 302 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 303 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 304 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 305 disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks)); 306 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); 307 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); 308 disk_super->cache_blocks = cpu_to_le32(0); 309 310 disk_super->read_hits = cpu_to_le32(0); 311 disk_super->read_misses = cpu_to_le32(0); 312 disk_super->write_hits = cpu_to_le32(0); 313 disk_super->write_misses = cpu_to_le32(0); 314 315 return dm_tm_commit(cmd->tm, sblock); 316 317bad_locked: 318 dm_bm_unlock(sblock); 319 return r; 320} 321 322static int __format_metadata(struct dm_cache_metadata *cmd) 323{ 324 int r; 325 326 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 327 &cmd->tm, &cmd->metadata_sm); 328 if (r < 0) { 329 DMERR("tm_create_with_sm failed"); 330 return r; 331 } 332 333 __setup_mapping_info(cmd); 334 335 r = dm_array_empty(&cmd->info, &cmd->root); 336 if (r < 0) 337 goto bad; 338 339 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 340 341 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); 342 if (r < 0) 343 goto bad; 344 345 cmd->discard_block_size = 0; 346 cmd->discard_nr_blocks = 0; 347 348 r = __write_initial_superblock(cmd); 349 if (r) 350 goto bad; 351 352 cmd->clean_when_opened = true; 353 return 0; 354 355bad: 356 dm_tm_destroy(cmd->tm); 357 dm_sm_destroy(cmd->metadata_sm); 358 359 return r; 360} 361 362static int __check_incompat_features(struct cache_disk_superblock *disk_super, 363 struct dm_cache_metadata *cmd) 364{ 365 uint32_t features; 366 367 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; 368 if (features) { 369 DMERR("could not access metadata due to unsupported optional features (%lx).", 370 (unsigned long)features); 371 return -EINVAL; 372 } 373 374 /* 375 * Check for read-only metadata to skip the following RDWR checks. 376 */ 377 if (get_disk_ro(cmd->bdev->bd_disk)) 378 return 0; 379 380 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; 381 if (features) { 382 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", 383 (unsigned long)features); 384 return -EINVAL; 385 } 386 387 return 0; 388} 389 390static int __open_metadata(struct dm_cache_metadata *cmd) 391{ 392 int r; 393 struct dm_block *sblock; 394 struct cache_disk_superblock *disk_super; 395 unsigned long sb_flags; 396 397 r = superblock_read_lock(cmd, &sblock); 398 if (r < 0) { 399 DMERR("couldn't read lock superblock"); 400 return r; 401 } 402 403 disk_super = dm_block_data(sblock); 404 405 r = __check_incompat_features(disk_super, cmd); 406 if (r < 0) 407 goto bad; 408 409 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 410 disk_super->metadata_space_map_root, 411 sizeof(disk_super->metadata_space_map_root), 412 &cmd->tm, &cmd->metadata_sm); 413 if (r < 0) { 414 DMERR("tm_open_with_sm failed"); 415 goto bad; 416 } 417 418 __setup_mapping_info(cmd); 419 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 420 sb_flags = le32_to_cpu(disk_super->flags); 421 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); 422 return dm_bm_unlock(sblock); 423 424bad: 425 dm_bm_unlock(sblock); 426 return r; 427} 428 429static int __open_or_format_metadata(struct dm_cache_metadata *cmd, 430 bool format_device) 431{ 432 int r; 433 bool unformatted = false; 434 435 r = __superblock_all_zeroes(cmd->bm, &unformatted); 436 if (r) 437 return r; 438 439 if (unformatted) 440 return format_device ? __format_metadata(cmd) : -EPERM; 441 442 return __open_metadata(cmd); 443} 444 445static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, 446 bool may_format_device) 447{ 448 int r; 449 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE, 450 CACHE_METADATA_CACHE_SIZE, 451 CACHE_MAX_CONCURRENT_LOCKS); 452 if (IS_ERR(cmd->bm)) { 453 DMERR("could not create block manager"); 454 return PTR_ERR(cmd->bm); 455 } 456 457 r = __open_or_format_metadata(cmd, may_format_device); 458 if (r) 459 dm_block_manager_destroy(cmd->bm); 460 461 return r; 462} 463 464static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) 465{ 466 dm_sm_destroy(cmd->metadata_sm); 467 dm_tm_destroy(cmd->tm); 468 dm_block_manager_destroy(cmd->bm); 469} 470 471typedef unsigned long (*flags_mutator)(unsigned long); 472 473static void update_flags(struct cache_disk_superblock *disk_super, 474 flags_mutator mutator) 475{ 476 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); 477 disk_super->flags = cpu_to_le32(sb_flags); 478} 479 480static unsigned long set_clean_shutdown(unsigned long flags) 481{ 482 set_bit(CLEAN_SHUTDOWN, &flags); 483 return flags; 484} 485 486static unsigned long clear_clean_shutdown(unsigned long flags) 487{ 488 clear_bit(CLEAN_SHUTDOWN, &flags); 489 return flags; 490} 491 492static void read_superblock_fields(struct dm_cache_metadata *cmd, 493 struct cache_disk_superblock *disk_super) 494{ 495 cmd->root = le64_to_cpu(disk_super->mapping_root); 496 cmd->hint_root = le64_to_cpu(disk_super->hint_root); 497 cmd->discard_root = le64_to_cpu(disk_super->discard_root); 498 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); 499 cmd->discard_nr_blocks = to_oblock(le64_to_cpu(disk_super->discard_nr_blocks)); 500 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); 501 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); 502 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); 503 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); 504 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); 505 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); 506 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); 507 508 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); 509 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); 510 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); 511 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); 512 513 cmd->changed = false; 514} 515 516/* 517 * The mutator updates the superblock flags. 518 */ 519static int __begin_transaction_flags(struct dm_cache_metadata *cmd, 520 flags_mutator mutator) 521{ 522 int r; 523 struct cache_disk_superblock *disk_super; 524 struct dm_block *sblock; 525 526 r = superblock_lock(cmd, &sblock); 527 if (r) 528 return r; 529 530 disk_super = dm_block_data(sblock); 531 update_flags(disk_super, mutator); 532 read_superblock_fields(cmd, disk_super); 533 dm_bm_unlock(sblock); 534 535 return dm_bm_flush(cmd->bm); 536} 537 538static int __begin_transaction(struct dm_cache_metadata *cmd) 539{ 540 int r; 541 struct cache_disk_superblock *disk_super; 542 struct dm_block *sblock; 543 544 /* 545 * We re-read the superblock every time. Shouldn't need to do this 546 * really. 547 */ 548 r = superblock_read_lock(cmd, &sblock); 549 if (r) 550 return r; 551 552 disk_super = dm_block_data(sblock); 553 read_superblock_fields(cmd, disk_super); 554 dm_bm_unlock(sblock); 555 556 return 0; 557} 558 559static int __commit_transaction(struct dm_cache_metadata *cmd, 560 flags_mutator mutator) 561{ 562 int r; 563 size_t metadata_len; 564 struct cache_disk_superblock *disk_super; 565 struct dm_block *sblock; 566 567 /* 568 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 569 */ 570 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 571 572 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 573 &cmd->discard_root); 574 if (r) 575 return r; 576 577 r = dm_tm_pre_commit(cmd->tm); 578 if (r < 0) 579 return r; 580 581 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 582 if (r < 0) 583 return r; 584 585 r = superblock_lock(cmd, &sblock); 586 if (r) 587 return r; 588 589 disk_super = dm_block_data(sblock); 590 591 if (mutator) 592 update_flags(disk_super, mutator); 593 594 disk_super->mapping_root = cpu_to_le64(cmd->root); 595 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 596 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 597 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 598 disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks)); 599 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 600 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 601 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); 602 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); 603 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); 604 605 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 606 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 607 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 608 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 609 610 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, 611 metadata_len); 612 if (r < 0) { 613 dm_bm_unlock(sblock); 614 return r; 615 } 616 617 return dm_tm_commit(cmd->tm, sblock); 618} 619 620/*----------------------------------------------------------------*/ 621 622/* 623 * The mappings are held in a dm-array that has 64-bit values stored in 624 * little-endian format. The index is the cblock, the high 48bits of the 625 * value are the oblock and the low 16 bit the flags. 626 */ 627#define FLAGS_MASK ((1 << 16) - 1) 628 629static __le64 pack_value(dm_oblock_t block, unsigned flags) 630{ 631 uint64_t value = from_oblock(block); 632 value <<= 16; 633 value = value | (flags & FLAGS_MASK); 634 return cpu_to_le64(value); 635} 636 637static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 638{ 639 uint64_t value = le64_to_cpu(value_le); 640 uint64_t b = value >> 16; 641 *block = to_oblock(b); 642 *flags = value & FLAGS_MASK; 643} 644 645/*----------------------------------------------------------------*/ 646 647struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 648 sector_t data_block_size, 649 bool may_format_device, 650 size_t policy_hint_size) 651{ 652 int r; 653 struct dm_cache_metadata *cmd; 654 655 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 656 if (!cmd) { 657 DMERR("could not allocate metadata struct"); 658 return NULL; 659 } 660 661 init_rwsem(&cmd->root_lock); 662 cmd->bdev = bdev; 663 cmd->data_block_size = data_block_size; 664 cmd->cache_blocks = 0; 665 cmd->policy_hint_size = policy_hint_size; 666 cmd->changed = true; 667 668 r = __create_persistent_data_objects(cmd, may_format_device); 669 if (r) { 670 kfree(cmd); 671 return ERR_PTR(r); 672 } 673 674 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 675 if (r < 0) { 676 dm_cache_metadata_close(cmd); 677 return ERR_PTR(r); 678 } 679 680 return cmd; 681} 682 683void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 684{ 685 __destroy_persistent_data_objects(cmd); 686 kfree(cmd); 687} 688 689/* 690 * Checks that the given cache block is either unmapped or clean. 691 */ 692static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b, 693 bool *result) 694{ 695 int r; 696 __le64 value; 697 dm_oblock_t ob; 698 unsigned flags; 699 700 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value); 701 if (r) { 702 DMERR("block_unmapped_or_clean failed"); 703 return r; 704 } 705 706 unpack_value(value, &ob, &flags); 707 *result = !((flags & M_VALID) && (flags & M_DIRTY)); 708 709 return 0; 710} 711 712static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd, 713 dm_cblock_t begin, dm_cblock_t end, 714 bool *result) 715{ 716 int r; 717 *result = true; 718 719 while (begin != end) { 720 r = block_unmapped_or_clean(cmd, begin, result); 721 if (r) 722 return r; 723 724 if (!*result) { 725 DMERR("cache block %llu is dirty", 726 (unsigned long long) from_cblock(begin)); 727 return 0; 728 } 729 730 begin = to_cblock(from_cblock(begin) + 1); 731 } 732 733 return 0; 734} 735 736int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) 737{ 738 int r; 739 bool clean; 740 __le64 null_mapping = pack_value(0, 0); 741 742 down_write(&cmd->root_lock); 743 __dm_bless_for_disk(&null_mapping); 744 745 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) { 746 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean); 747 if (r) { 748 __dm_unbless_for_disk(&null_mapping); 749 goto out; 750 } 751 752 if (!clean) { 753 DMERR("unable to shrink cache due to dirty blocks"); 754 r = -EINVAL; 755 __dm_unbless_for_disk(&null_mapping); 756 goto out; 757 } 758 } 759 760 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), 761 from_cblock(new_cache_size), 762 &null_mapping, &cmd->root); 763 if (!r) 764 cmd->cache_blocks = new_cache_size; 765 cmd->changed = true; 766 767out: 768 up_write(&cmd->root_lock); 769 770 return r; 771} 772 773int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 774 sector_t discard_block_size, 775 dm_oblock_t new_nr_entries) 776{ 777 int r; 778 779 down_write(&cmd->root_lock); 780 r = dm_bitset_resize(&cmd->discard_info, 781 cmd->discard_root, 782 from_oblock(cmd->discard_nr_blocks), 783 from_oblock(new_nr_entries), 784 false, &cmd->discard_root); 785 if (!r) { 786 cmd->discard_block_size = discard_block_size; 787 cmd->discard_nr_blocks = new_nr_entries; 788 } 789 790 cmd->changed = true; 791 up_write(&cmd->root_lock); 792 793 return r; 794} 795 796static int __set_discard(struct dm_cache_metadata *cmd, dm_oblock_t b) 797{ 798 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, 799 from_oblock(b), &cmd->discard_root); 800} 801 802static int __clear_discard(struct dm_cache_metadata *cmd, dm_oblock_t b) 803{ 804 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, 805 from_oblock(b), &cmd->discard_root); 806} 807 808static int __is_discarded(struct dm_cache_metadata *cmd, dm_oblock_t b, 809 bool *is_discarded) 810{ 811 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root, 812 from_oblock(b), &cmd->discard_root, 813 is_discarded); 814} 815 816static int __discard(struct dm_cache_metadata *cmd, 817 dm_oblock_t dblock, bool discard) 818{ 819 int r; 820 821 r = (discard ? __set_discard : __clear_discard)(cmd, dblock); 822 if (r) 823 return r; 824 825 cmd->changed = true; 826 return 0; 827} 828 829int dm_cache_set_discard(struct dm_cache_metadata *cmd, 830 dm_oblock_t dblock, bool discard) 831{ 832 int r; 833 834 down_write(&cmd->root_lock); 835 r = __discard(cmd, dblock, discard); 836 up_write(&cmd->root_lock); 837 838 return r; 839} 840 841static int __load_discards(struct dm_cache_metadata *cmd, 842 load_discard_fn fn, void *context) 843{ 844 int r = 0; 845 dm_block_t b; 846 bool discard; 847 848 for (b = 0; b < from_oblock(cmd->discard_nr_blocks); b++) { 849 dm_oblock_t dblock = to_oblock(b); 850 851 if (cmd->clean_when_opened) { 852 r = __is_discarded(cmd, dblock, &discard); 853 if (r) 854 return r; 855 } else 856 discard = false; 857 858 r = fn(context, cmd->discard_block_size, dblock, discard); 859 if (r) 860 break; 861 } 862 863 return r; 864} 865 866int dm_cache_load_discards(struct dm_cache_metadata *cmd, 867 load_discard_fn fn, void *context) 868{ 869 int r; 870 871 down_read(&cmd->root_lock); 872 r = __load_discards(cmd, fn, context); 873 up_read(&cmd->root_lock); 874 875 return r; 876} 877 878dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd) 879{ 880 dm_cblock_t r; 881 882 down_read(&cmd->root_lock); 883 r = cmd->cache_blocks; 884 up_read(&cmd->root_lock); 885 886 return r; 887} 888 889static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 890{ 891 int r; 892 __le64 value = pack_value(0, 0); 893 894 __dm_bless_for_disk(&value); 895 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 896 &value, &cmd->root); 897 if (r) 898 return r; 899 900 cmd->changed = true; 901 return 0; 902} 903 904int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 905{ 906 int r; 907 908 down_write(&cmd->root_lock); 909 r = __remove(cmd, cblock); 910 up_write(&cmd->root_lock); 911 912 return r; 913} 914 915static int __insert(struct dm_cache_metadata *cmd, 916 dm_cblock_t cblock, dm_oblock_t oblock) 917{ 918 int r; 919 __le64 value = pack_value(oblock, M_VALID); 920 __dm_bless_for_disk(&value); 921 922 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 923 &value, &cmd->root); 924 if (r) 925 return r; 926 927 cmd->changed = true; 928 return 0; 929} 930 931int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, 932 dm_cblock_t cblock, dm_oblock_t oblock) 933{ 934 int r; 935 936 down_write(&cmd->root_lock); 937 r = __insert(cmd, cblock, oblock); 938 up_write(&cmd->root_lock); 939 940 return r; 941} 942 943struct thunk { 944 load_mapping_fn fn; 945 void *context; 946 947 struct dm_cache_metadata *cmd; 948 bool respect_dirty_flags; 949 bool hints_valid; 950}; 951 952static bool policy_unchanged(struct dm_cache_metadata *cmd, 953 struct dm_cache_policy *policy) 954{ 955 const char *policy_name = dm_cache_policy_get_name(policy); 956 const unsigned *policy_version = dm_cache_policy_get_version(policy); 957 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); 958 959 /* 960 * Ensure policy names match. 961 */ 962 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) 963 return false; 964 965 /* 966 * Ensure policy major versions match. 967 */ 968 if (cmd->policy_version[0] != policy_version[0]) 969 return false; 970 971 /* 972 * Ensure policy hint sizes match. 973 */ 974 if (cmd->policy_hint_size != policy_hint_size) 975 return false; 976 977 return true; 978} 979 980static bool hints_array_initialized(struct dm_cache_metadata *cmd) 981{ 982 return cmd->hint_root && cmd->policy_hint_size; 983} 984 985static bool hints_array_available(struct dm_cache_metadata *cmd, 986 struct dm_cache_policy *policy) 987{ 988 return cmd->clean_when_opened && policy_unchanged(cmd, policy) && 989 hints_array_initialized(cmd); 990} 991 992static int __load_mapping(void *context, uint64_t cblock, void *leaf) 993{ 994 int r = 0; 995 bool dirty; 996 __le64 value; 997 __le32 hint_value = 0; 998 dm_oblock_t oblock; 999 unsigned flags; 1000 struct thunk *thunk = context; 1001 struct dm_cache_metadata *cmd = thunk->cmd; 1002 1003 memcpy(&value, leaf, sizeof(value)); 1004 unpack_value(value, &oblock, &flags); 1005 1006 if (flags & M_VALID) { 1007 if (thunk->hints_valid) { 1008 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root, 1009 cblock, &hint_value); 1010 if (r && r != -ENODATA) 1011 return r; 1012 } 1013 1014 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true; 1015 r = thunk->fn(thunk->context, oblock, to_cblock(cblock), 1016 dirty, le32_to_cpu(hint_value), thunk->hints_valid); 1017 } 1018 1019 return r; 1020} 1021 1022static int __load_mappings(struct dm_cache_metadata *cmd, 1023 struct dm_cache_policy *policy, 1024 load_mapping_fn fn, void *context) 1025{ 1026 struct thunk thunk; 1027 1028 thunk.fn = fn; 1029 thunk.context = context; 1030 1031 thunk.cmd = cmd; 1032 thunk.respect_dirty_flags = cmd->clean_when_opened; 1033 thunk.hints_valid = hints_array_available(cmd, policy); 1034 1035 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk); 1036} 1037 1038int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 1039 struct dm_cache_policy *policy, 1040 load_mapping_fn fn, void *context) 1041{ 1042 int r; 1043 1044 down_read(&cmd->root_lock); 1045 r = __load_mappings(cmd, policy, fn, context); 1046 up_read(&cmd->root_lock); 1047 1048 return r; 1049} 1050 1051static int __dump_mapping(void *context, uint64_t cblock, void *leaf) 1052{ 1053 int r = 0; 1054 __le64 value; 1055 dm_oblock_t oblock; 1056 unsigned flags; 1057 1058 memcpy(&value, leaf, sizeof(value)); 1059 unpack_value(value, &oblock, &flags); 1060 1061 return r; 1062} 1063 1064static int __dump_mappings(struct dm_cache_metadata *cmd) 1065{ 1066 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); 1067} 1068 1069void dm_cache_dump(struct dm_cache_metadata *cmd) 1070{ 1071 down_read(&cmd->root_lock); 1072 __dump_mappings(cmd); 1073 up_read(&cmd->root_lock); 1074} 1075 1076int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) 1077{ 1078 int r; 1079 1080 down_read(&cmd->root_lock); 1081 r = cmd->changed; 1082 up_read(&cmd->root_lock); 1083 1084 return r; 1085} 1086 1087static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) 1088{ 1089 int r; 1090 unsigned flags; 1091 dm_oblock_t oblock; 1092 __le64 value; 1093 1094 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); 1095 if (r) 1096 return r; 1097 1098 unpack_value(value, &oblock, &flags); 1099 1100 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) 1101 /* nothing to be done */ 1102 return 0; 1103 1104 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); 1105 __dm_bless_for_disk(&value); 1106 1107 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1108 &value, &cmd->root); 1109 if (r) 1110 return r; 1111 1112 cmd->changed = true; 1113 return 0; 1114 1115} 1116 1117int dm_cache_set_dirty(struct dm_cache_metadata *cmd, 1118 dm_cblock_t cblock, bool dirty) 1119{ 1120 int r; 1121 1122 down_write(&cmd->root_lock); 1123 r = __dirty(cmd, cblock, dirty); 1124 up_write(&cmd->root_lock); 1125 1126 return r; 1127} 1128 1129void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 1130 struct dm_cache_statistics *stats) 1131{ 1132 down_read(&cmd->root_lock); 1133 *stats = cmd->stats; 1134 up_read(&cmd->root_lock); 1135} 1136 1137void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 1138 struct dm_cache_statistics *stats) 1139{ 1140 down_write(&cmd->root_lock); 1141 cmd->stats = *stats; 1142 up_write(&cmd->root_lock); 1143} 1144 1145int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) 1146{ 1147 int r; 1148 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1149 clear_clean_shutdown); 1150 1151 down_write(&cmd->root_lock); 1152 r = __commit_transaction(cmd, mutator); 1153 if (r) 1154 goto out; 1155 1156 r = __begin_transaction(cmd); 1157 1158out: 1159 up_write(&cmd->root_lock); 1160 return r; 1161} 1162 1163int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1164 dm_block_t *result) 1165{ 1166 int r = -EINVAL; 1167 1168 down_read(&cmd->root_lock); 1169 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1170 up_read(&cmd->root_lock); 1171 1172 return r; 1173} 1174 1175int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1176 dm_block_t *result) 1177{ 1178 int r = -EINVAL; 1179 1180 down_read(&cmd->root_lock); 1181 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1182 up_read(&cmd->root_lock); 1183 1184 return r; 1185} 1186 1187/*----------------------------------------------------------------*/ 1188 1189static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1190{ 1191 int r; 1192 __le32 value; 1193 size_t hint_size; 1194 const char *policy_name = dm_cache_policy_get_name(policy); 1195 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1196 1197 if (!policy_name[0] || 1198 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1199 return -EINVAL; 1200 1201 if (!policy_unchanged(cmd, policy)) { 1202 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1203 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); 1204 1205 hint_size = dm_cache_policy_get_hint_size(policy); 1206 if (!hint_size) 1207 return 0; /* short-circuit hints initialization */ 1208 cmd->policy_hint_size = hint_size; 1209 1210 if (cmd->hint_root) { 1211 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1212 if (r) 1213 return r; 1214 } 1215 1216 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root); 1217 if (r) 1218 return r; 1219 1220 value = cpu_to_le32(0); 1221 __dm_bless_for_disk(&value); 1222 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0, 1223 from_cblock(cmd->cache_blocks), 1224 &value, &cmd->hint_root); 1225 if (r) 1226 return r; 1227 } 1228 1229 return 0; 1230} 1231 1232int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1233{ 1234 int r; 1235 1236 down_write(&cmd->root_lock); 1237 r = begin_hints(cmd, policy); 1238 up_write(&cmd->root_lock); 1239 1240 return r; 1241} 1242 1243static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, 1244 uint32_t hint) 1245{ 1246 int r; 1247 __le32 value = cpu_to_le32(hint); 1248 __dm_bless_for_disk(&value); 1249 1250 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root, 1251 from_cblock(cblock), &value, &cmd->hint_root); 1252 cmd->changed = true; 1253 1254 return r; 1255} 1256 1257int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, 1258 uint32_t hint) 1259{ 1260 int r; 1261 1262 if (!hints_array_initialized(cmd)) 1263 return 0; 1264 1265 down_write(&cmd->root_lock); 1266 r = save_hint(cmd, cblock, hint); 1267 up_write(&cmd->root_lock); 1268 1269 return r; 1270} 1271 1272int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result) 1273{ 1274 return blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result); 1275} 1276