dm-cache-metadata.c revision 53d498198d3e8bce4287112beafc30befcba98cc
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_dblock_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_dblock(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_dblock(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); 533 534 return dm_bm_flush_and_unlock(cmd->bm, sblock); 535} 536 537static int __begin_transaction(struct dm_cache_metadata *cmd) 538{ 539 int r; 540 struct cache_disk_superblock *disk_super; 541 struct dm_block *sblock; 542 543 /* 544 * We re-read the superblock every time. Shouldn't need to do this 545 * really. 546 */ 547 r = superblock_read_lock(cmd, &sblock); 548 if (r) 549 return r; 550 551 disk_super = dm_block_data(sblock); 552 read_superblock_fields(cmd, disk_super); 553 dm_bm_unlock(sblock); 554 555 return 0; 556} 557 558static int __commit_transaction(struct dm_cache_metadata *cmd, 559 flags_mutator mutator) 560{ 561 int r; 562 size_t metadata_len; 563 struct cache_disk_superblock *disk_super; 564 struct dm_block *sblock; 565 566 /* 567 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 568 */ 569 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 570 571 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 572 &cmd->discard_root); 573 if (r) 574 return r; 575 576 r = dm_tm_pre_commit(cmd->tm); 577 if (r < 0) 578 return r; 579 580 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 581 if (r < 0) 582 return r; 583 584 r = superblock_lock(cmd, &sblock); 585 if (r) 586 return r; 587 588 disk_super = dm_block_data(sblock); 589 590 if (mutator) 591 update_flags(disk_super, mutator); 592 593 disk_super->mapping_root = cpu_to_le64(cmd->root); 594 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 595 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 596 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 597 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 598 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 599 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 600 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); 601 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); 602 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); 603 604 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 605 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 606 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 607 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 608 609 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, 610 metadata_len); 611 if (r < 0) { 612 dm_bm_unlock(sblock); 613 return r; 614 } 615 616 return dm_tm_commit(cmd->tm, sblock); 617} 618 619/*----------------------------------------------------------------*/ 620 621/* 622 * The mappings are held in a dm-array that has 64-bit values stored in 623 * little-endian format. The index is the cblock, the high 48bits of the 624 * value are the oblock and the low 16 bit the flags. 625 */ 626#define FLAGS_MASK ((1 << 16) - 1) 627 628static __le64 pack_value(dm_oblock_t block, unsigned flags) 629{ 630 uint64_t value = from_oblock(block); 631 value <<= 16; 632 value = value | (flags & FLAGS_MASK); 633 return cpu_to_le64(value); 634} 635 636static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 637{ 638 uint64_t value = le64_to_cpu(value_le); 639 uint64_t b = value >> 16; 640 *block = to_oblock(b); 641 *flags = value & FLAGS_MASK; 642} 643 644/*----------------------------------------------------------------*/ 645 646struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 647 sector_t data_block_size, 648 bool may_format_device, 649 size_t policy_hint_size) 650{ 651 int r; 652 struct dm_cache_metadata *cmd; 653 654 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 655 if (!cmd) { 656 DMERR("could not allocate metadata struct"); 657 return NULL; 658 } 659 660 init_rwsem(&cmd->root_lock); 661 cmd->bdev = bdev; 662 cmd->data_block_size = data_block_size; 663 cmd->cache_blocks = 0; 664 cmd->policy_hint_size = policy_hint_size; 665 cmd->changed = true; 666 667 r = __create_persistent_data_objects(cmd, may_format_device); 668 if (r) { 669 kfree(cmd); 670 return ERR_PTR(r); 671 } 672 673 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 674 if (r < 0) { 675 dm_cache_metadata_close(cmd); 676 return ERR_PTR(r); 677 } 678 679 return cmd; 680} 681 682void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 683{ 684 __destroy_persistent_data_objects(cmd); 685 kfree(cmd); 686} 687 688/* 689 * Checks that the given cache block is either unmapped or clean. 690 */ 691static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b, 692 bool *result) 693{ 694 int r; 695 __le64 value; 696 dm_oblock_t ob; 697 unsigned flags; 698 699 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value); 700 if (r) { 701 DMERR("block_unmapped_or_clean failed"); 702 return r; 703 } 704 705 unpack_value(value, &ob, &flags); 706 *result = !((flags & M_VALID) && (flags & M_DIRTY)); 707 708 return 0; 709} 710 711static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd, 712 dm_cblock_t begin, dm_cblock_t end, 713 bool *result) 714{ 715 int r; 716 *result = true; 717 718 while (begin != end) { 719 r = block_unmapped_or_clean(cmd, begin, result); 720 if (r) 721 return r; 722 723 if (!*result) { 724 DMERR("cache block %llu is dirty", 725 (unsigned long long) from_cblock(begin)); 726 return 0; 727 } 728 729 begin = to_cblock(from_cblock(begin) + 1); 730 } 731 732 return 0; 733} 734 735int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) 736{ 737 int r; 738 bool clean; 739 __le64 null_mapping = pack_value(0, 0); 740 741 down_write(&cmd->root_lock); 742 __dm_bless_for_disk(&null_mapping); 743 744 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) { 745 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean); 746 if (r) { 747 __dm_unbless_for_disk(&null_mapping); 748 goto out; 749 } 750 751 if (!clean) { 752 DMERR("unable to shrink cache due to dirty blocks"); 753 r = -EINVAL; 754 __dm_unbless_for_disk(&null_mapping); 755 goto out; 756 } 757 } 758 759 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), 760 from_cblock(new_cache_size), 761 &null_mapping, &cmd->root); 762 if (!r) 763 cmd->cache_blocks = new_cache_size; 764 cmd->changed = true; 765 766out: 767 up_write(&cmd->root_lock); 768 769 return r; 770} 771 772int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 773 sector_t discard_block_size, 774 dm_dblock_t new_nr_entries) 775{ 776 int r; 777 778 down_write(&cmd->root_lock); 779 r = dm_bitset_resize(&cmd->discard_info, 780 cmd->discard_root, 781 from_dblock(cmd->discard_nr_blocks), 782 from_dblock(new_nr_entries), 783 false, &cmd->discard_root); 784 if (!r) { 785 cmd->discard_block_size = discard_block_size; 786 cmd->discard_nr_blocks = new_nr_entries; 787 } 788 789 cmd->changed = true; 790 up_write(&cmd->root_lock); 791 792 return r; 793} 794 795static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 796{ 797 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, 798 from_dblock(b), &cmd->discard_root); 799} 800 801static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 802{ 803 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, 804 from_dblock(b), &cmd->discard_root); 805} 806 807static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b, 808 bool *is_discarded) 809{ 810 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root, 811 from_dblock(b), &cmd->discard_root, 812 is_discarded); 813} 814 815static int __discard(struct dm_cache_metadata *cmd, 816 dm_dblock_t dblock, bool discard) 817{ 818 int r; 819 820 r = (discard ? __set_discard : __clear_discard)(cmd, dblock); 821 if (r) 822 return r; 823 824 cmd->changed = true; 825 return 0; 826} 827 828int dm_cache_set_discard(struct dm_cache_metadata *cmd, 829 dm_dblock_t dblock, bool discard) 830{ 831 int r; 832 833 down_write(&cmd->root_lock); 834 r = __discard(cmd, dblock, discard); 835 up_write(&cmd->root_lock); 836 837 return r; 838} 839 840static int __load_discards(struct dm_cache_metadata *cmd, 841 load_discard_fn fn, void *context) 842{ 843 int r = 0; 844 dm_block_t b; 845 bool discard; 846 847 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { 848 dm_dblock_t dblock = to_dblock(b); 849 850 if (cmd->clean_when_opened) { 851 r = __is_discarded(cmd, dblock, &discard); 852 if (r) 853 return r; 854 } else 855 discard = false; 856 857 r = fn(context, cmd->discard_block_size, dblock, discard); 858 if (r) 859 break; 860 } 861 862 return r; 863} 864 865int dm_cache_load_discards(struct dm_cache_metadata *cmd, 866 load_discard_fn fn, void *context) 867{ 868 int r; 869 870 down_read(&cmd->root_lock); 871 r = __load_discards(cmd, fn, context); 872 up_read(&cmd->root_lock); 873 874 return r; 875} 876 877dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd) 878{ 879 dm_cblock_t r; 880 881 down_read(&cmd->root_lock); 882 r = cmd->cache_blocks; 883 up_read(&cmd->root_lock); 884 885 return r; 886} 887 888static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 889{ 890 int r; 891 __le64 value = pack_value(0, 0); 892 893 __dm_bless_for_disk(&value); 894 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 895 &value, &cmd->root); 896 if (r) 897 return r; 898 899 cmd->changed = true; 900 return 0; 901} 902 903int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 904{ 905 int r; 906 907 down_write(&cmd->root_lock); 908 r = __remove(cmd, cblock); 909 up_write(&cmd->root_lock); 910 911 return r; 912} 913 914static int __insert(struct dm_cache_metadata *cmd, 915 dm_cblock_t cblock, dm_oblock_t oblock) 916{ 917 int r; 918 __le64 value = pack_value(oblock, M_VALID); 919 __dm_bless_for_disk(&value); 920 921 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 922 &value, &cmd->root); 923 if (r) 924 return r; 925 926 cmd->changed = true; 927 return 0; 928} 929 930int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, 931 dm_cblock_t cblock, dm_oblock_t oblock) 932{ 933 int r; 934 935 down_write(&cmd->root_lock); 936 r = __insert(cmd, cblock, oblock); 937 up_write(&cmd->root_lock); 938 939 return r; 940} 941 942struct thunk { 943 load_mapping_fn fn; 944 void *context; 945 946 struct dm_cache_metadata *cmd; 947 bool respect_dirty_flags; 948 bool hints_valid; 949}; 950 951static bool policy_unchanged(struct dm_cache_metadata *cmd, 952 struct dm_cache_policy *policy) 953{ 954 const char *policy_name = dm_cache_policy_get_name(policy); 955 const unsigned *policy_version = dm_cache_policy_get_version(policy); 956 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); 957 958 /* 959 * Ensure policy names match. 960 */ 961 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) 962 return false; 963 964 /* 965 * Ensure policy major versions match. 966 */ 967 if (cmd->policy_version[0] != policy_version[0]) 968 return false; 969 970 /* 971 * Ensure policy hint sizes match. 972 */ 973 if (cmd->policy_hint_size != policy_hint_size) 974 return false; 975 976 return true; 977} 978 979static bool hints_array_initialized(struct dm_cache_metadata *cmd) 980{ 981 return cmd->hint_root && cmd->policy_hint_size; 982} 983 984static bool hints_array_available(struct dm_cache_metadata *cmd, 985 struct dm_cache_policy *policy) 986{ 987 return cmd->clean_when_opened && policy_unchanged(cmd, policy) && 988 hints_array_initialized(cmd); 989} 990 991static int __load_mapping(void *context, uint64_t cblock, void *leaf) 992{ 993 int r = 0; 994 bool dirty; 995 __le64 value; 996 __le32 hint_value = 0; 997 dm_oblock_t oblock; 998 unsigned flags; 999 struct thunk *thunk = context; 1000 struct dm_cache_metadata *cmd = thunk->cmd; 1001 1002 memcpy(&value, leaf, sizeof(value)); 1003 unpack_value(value, &oblock, &flags); 1004 1005 if (flags & M_VALID) { 1006 if (thunk->hints_valid) { 1007 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root, 1008 cblock, &hint_value); 1009 if (r && r != -ENODATA) 1010 return r; 1011 } 1012 1013 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true; 1014 r = thunk->fn(thunk->context, oblock, to_cblock(cblock), 1015 dirty, le32_to_cpu(hint_value), thunk->hints_valid); 1016 } 1017 1018 return r; 1019} 1020 1021static int __load_mappings(struct dm_cache_metadata *cmd, 1022 struct dm_cache_policy *policy, 1023 load_mapping_fn fn, void *context) 1024{ 1025 struct thunk thunk; 1026 1027 thunk.fn = fn; 1028 thunk.context = context; 1029 1030 thunk.cmd = cmd; 1031 thunk.respect_dirty_flags = cmd->clean_when_opened; 1032 thunk.hints_valid = hints_array_available(cmd, policy); 1033 1034 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk); 1035} 1036 1037int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 1038 struct dm_cache_policy *policy, 1039 load_mapping_fn fn, void *context) 1040{ 1041 int r; 1042 1043 down_read(&cmd->root_lock); 1044 r = __load_mappings(cmd, policy, fn, context); 1045 up_read(&cmd->root_lock); 1046 1047 return r; 1048} 1049 1050static int __dump_mapping(void *context, uint64_t cblock, void *leaf) 1051{ 1052 int r = 0; 1053 __le64 value; 1054 dm_oblock_t oblock; 1055 unsigned flags; 1056 1057 memcpy(&value, leaf, sizeof(value)); 1058 unpack_value(value, &oblock, &flags); 1059 1060 return r; 1061} 1062 1063static int __dump_mappings(struct dm_cache_metadata *cmd) 1064{ 1065 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); 1066} 1067 1068void dm_cache_dump(struct dm_cache_metadata *cmd) 1069{ 1070 down_read(&cmd->root_lock); 1071 __dump_mappings(cmd); 1072 up_read(&cmd->root_lock); 1073} 1074 1075int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) 1076{ 1077 int r; 1078 1079 down_read(&cmd->root_lock); 1080 r = cmd->changed; 1081 up_read(&cmd->root_lock); 1082 1083 return r; 1084} 1085 1086static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) 1087{ 1088 int r; 1089 unsigned flags; 1090 dm_oblock_t oblock; 1091 __le64 value; 1092 1093 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); 1094 if (r) 1095 return r; 1096 1097 unpack_value(value, &oblock, &flags); 1098 1099 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) 1100 /* nothing to be done */ 1101 return 0; 1102 1103 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); 1104 __dm_bless_for_disk(&value); 1105 1106 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1107 &value, &cmd->root); 1108 if (r) 1109 return r; 1110 1111 cmd->changed = true; 1112 return 0; 1113 1114} 1115 1116int dm_cache_set_dirty(struct dm_cache_metadata *cmd, 1117 dm_cblock_t cblock, bool dirty) 1118{ 1119 int r; 1120 1121 down_write(&cmd->root_lock); 1122 r = __dirty(cmd, cblock, dirty); 1123 up_write(&cmd->root_lock); 1124 1125 return r; 1126} 1127 1128void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 1129 struct dm_cache_statistics *stats) 1130{ 1131 down_read(&cmd->root_lock); 1132 *stats = cmd->stats; 1133 up_read(&cmd->root_lock); 1134} 1135 1136void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 1137 struct dm_cache_statistics *stats) 1138{ 1139 down_write(&cmd->root_lock); 1140 cmd->stats = *stats; 1141 up_write(&cmd->root_lock); 1142} 1143 1144int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) 1145{ 1146 int r; 1147 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1148 clear_clean_shutdown); 1149 1150 down_write(&cmd->root_lock); 1151 r = __commit_transaction(cmd, mutator); 1152 if (r) 1153 goto out; 1154 1155 r = __begin_transaction(cmd); 1156 1157out: 1158 up_write(&cmd->root_lock); 1159 return r; 1160} 1161 1162int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1163 dm_block_t *result) 1164{ 1165 int r = -EINVAL; 1166 1167 down_read(&cmd->root_lock); 1168 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1169 up_read(&cmd->root_lock); 1170 1171 return r; 1172} 1173 1174int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1175 dm_block_t *result) 1176{ 1177 int r = -EINVAL; 1178 1179 down_read(&cmd->root_lock); 1180 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1181 up_read(&cmd->root_lock); 1182 1183 return r; 1184} 1185 1186/*----------------------------------------------------------------*/ 1187 1188static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1189{ 1190 int r; 1191 __le32 value; 1192 size_t hint_size; 1193 const char *policy_name = dm_cache_policy_get_name(policy); 1194 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1195 1196 if (!policy_name[0] || 1197 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1198 return -EINVAL; 1199 1200 if (!policy_unchanged(cmd, policy)) { 1201 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1202 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); 1203 1204 hint_size = dm_cache_policy_get_hint_size(policy); 1205 if (!hint_size) 1206 return 0; /* short-circuit hints initialization */ 1207 cmd->policy_hint_size = hint_size; 1208 1209 if (cmd->hint_root) { 1210 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1211 if (r) 1212 return r; 1213 } 1214 1215 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root); 1216 if (r) 1217 return r; 1218 1219 value = cpu_to_le32(0); 1220 __dm_bless_for_disk(&value); 1221 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0, 1222 from_cblock(cmd->cache_blocks), 1223 &value, &cmd->hint_root); 1224 if (r) 1225 return r; 1226 } 1227 1228 return 0; 1229} 1230 1231int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1232{ 1233 int r; 1234 1235 down_write(&cmd->root_lock); 1236 r = begin_hints(cmd, policy); 1237 up_write(&cmd->root_lock); 1238 1239 return r; 1240} 1241 1242static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, 1243 uint32_t hint) 1244{ 1245 int r; 1246 __le32 value = cpu_to_le32(hint); 1247 __dm_bless_for_disk(&value); 1248 1249 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root, 1250 from_cblock(cblock), &value, &cmd->hint_root); 1251 cmd->changed = true; 1252 1253 return r; 1254} 1255 1256int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, 1257 uint32_t hint) 1258{ 1259 int r; 1260 1261 if (!hints_array_initialized(cmd)) 1262 return 0; 1263 1264 down_write(&cmd->root_lock); 1265 r = save_hint(cmd, cblock, hint); 1266 up_write(&cmd->root_lock); 1267 1268 return r; 1269} 1270 1271int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result) 1272{ 1273 return blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result); 1274} 1275