dm-cache-metadata.c revision 5a32083d03fb543f63489b2946c4948398579ba0
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 * Reading the space map root can fail, so we read it into this 126 * buffer before the superblock is locked and updated. 127 */ 128 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 129}; 130 131/*------------------------------------------------------------------- 132 * superblock validator 133 *-----------------------------------------------------------------*/ 134 135#define SUPERBLOCK_CSUM_XOR 9031977 136 137static void sb_prepare_for_write(struct dm_block_validator *v, 138 struct dm_block *b, 139 size_t sb_block_size) 140{ 141 struct cache_disk_superblock *disk_super = dm_block_data(b); 142 143 disk_super->blocknr = cpu_to_le64(dm_block_location(b)); 144 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 145 sb_block_size - sizeof(__le32), 146 SUPERBLOCK_CSUM_XOR)); 147} 148 149static int check_metadata_version(struct cache_disk_superblock *disk_super) 150{ 151 uint32_t metadata_version = le32_to_cpu(disk_super->version); 152 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) { 153 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.", 154 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION); 155 return -EINVAL; 156 } 157 158 return 0; 159} 160 161static int sb_check(struct dm_block_validator *v, 162 struct dm_block *b, 163 size_t sb_block_size) 164{ 165 struct cache_disk_superblock *disk_super = dm_block_data(b); 166 __le32 csum_le; 167 168 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { 169 DMERR("sb_check failed: blocknr %llu: wanted %llu", 170 le64_to_cpu(disk_super->blocknr), 171 (unsigned long long)dm_block_location(b)); 172 return -ENOTBLK; 173 } 174 175 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { 176 DMERR("sb_check failed: magic %llu: wanted %llu", 177 le64_to_cpu(disk_super->magic), 178 (unsigned long long)CACHE_SUPERBLOCK_MAGIC); 179 return -EILSEQ; 180 } 181 182 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 183 sb_block_size - sizeof(__le32), 184 SUPERBLOCK_CSUM_XOR)); 185 if (csum_le != disk_super->csum) { 186 DMERR("sb_check failed: csum %u: wanted %u", 187 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); 188 return -EILSEQ; 189 } 190 191 return check_metadata_version(disk_super); 192} 193 194static struct dm_block_validator sb_validator = { 195 .name = "superblock", 196 .prepare_for_write = sb_prepare_for_write, 197 .check = sb_check 198}; 199 200/*----------------------------------------------------------------*/ 201 202static int superblock_read_lock(struct dm_cache_metadata *cmd, 203 struct dm_block **sblock) 204{ 205 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 206 &sb_validator, sblock); 207} 208 209static int superblock_lock_zero(struct dm_cache_metadata *cmd, 210 struct dm_block **sblock) 211{ 212 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 213 &sb_validator, sblock); 214} 215 216static int superblock_lock(struct dm_cache_metadata *cmd, 217 struct dm_block **sblock) 218{ 219 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 220 &sb_validator, sblock); 221} 222 223/*----------------------------------------------------------------*/ 224 225static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result) 226{ 227 int r; 228 unsigned i; 229 struct dm_block *b; 230 __le64 *data_le, zero = cpu_to_le64(0); 231 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 232 233 /* 234 * We can't use a validator here - it may be all zeroes. 235 */ 236 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); 237 if (r) 238 return r; 239 240 data_le = dm_block_data(b); 241 *result = true; 242 for (i = 0; i < sb_block_size; i++) { 243 if (data_le[i] != zero) { 244 *result = false; 245 break; 246 } 247 } 248 249 return dm_bm_unlock(b); 250} 251 252static void __setup_mapping_info(struct dm_cache_metadata *cmd) 253{ 254 struct dm_btree_value_type vt; 255 256 vt.context = NULL; 257 vt.size = sizeof(__le64); 258 vt.inc = NULL; 259 vt.dec = NULL; 260 vt.equal = NULL; 261 dm_array_info_init(&cmd->info, cmd->tm, &vt); 262 263 if (cmd->policy_hint_size) { 264 vt.size = sizeof(__le32); 265 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); 266 } 267} 268 269static int __save_sm_root(struct dm_cache_metadata *cmd) 270{ 271 int r; 272 size_t metadata_len; 273 274 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 275 if (r < 0) 276 return r; 277 278 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root, 279 metadata_len); 280} 281 282static void __copy_sm_root(struct dm_cache_metadata *cmd, 283 struct cache_disk_superblock *disk_super) 284{ 285 memcpy(&disk_super->metadata_space_map_root, 286 &cmd->metadata_space_map_root, 287 sizeof(cmd->metadata_space_map_root)); 288} 289 290static int __write_initial_superblock(struct dm_cache_metadata *cmd) 291{ 292 int r; 293 struct dm_block *sblock; 294 struct cache_disk_superblock *disk_super; 295 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT; 296 297 /* FIXME: see if we can lose the max sectors limit */ 298 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) 299 bdev_size = DM_CACHE_METADATA_MAX_SECTORS; 300 301 r = dm_tm_pre_commit(cmd->tm); 302 if (r < 0) 303 return r; 304 305 /* 306 * dm_sm_copy_root() can fail. So we need to do it before we start 307 * updating the superblock. 308 */ 309 r = __save_sm_root(cmd); 310 if (r) 311 return r; 312 313 r = superblock_lock_zero(cmd, &sblock); 314 if (r) 315 return r; 316 317 disk_super = dm_block_data(sblock); 318 disk_super->flags = 0; 319 memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); 320 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); 321 disk_super->version = cpu_to_le32(MAX_CACHE_VERSION); 322 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); 323 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); 324 disk_super->policy_hint_size = 0; 325 326 __copy_sm_root(cmd, disk_super); 327 328 disk_super->mapping_root = cpu_to_le64(cmd->root); 329 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 330 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 331 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 332 disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks)); 333 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); 334 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); 335 disk_super->cache_blocks = cpu_to_le32(0); 336 337 disk_super->read_hits = cpu_to_le32(0); 338 disk_super->read_misses = cpu_to_le32(0); 339 disk_super->write_hits = cpu_to_le32(0); 340 disk_super->write_misses = cpu_to_le32(0); 341 342 return dm_tm_commit(cmd->tm, sblock); 343} 344 345static int __format_metadata(struct dm_cache_metadata *cmd) 346{ 347 int r; 348 349 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 350 &cmd->tm, &cmd->metadata_sm); 351 if (r < 0) { 352 DMERR("tm_create_with_sm failed"); 353 return r; 354 } 355 356 __setup_mapping_info(cmd); 357 358 r = dm_array_empty(&cmd->info, &cmd->root); 359 if (r < 0) 360 goto bad; 361 362 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 363 364 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); 365 if (r < 0) 366 goto bad; 367 368 cmd->discard_block_size = 0; 369 cmd->discard_nr_blocks = 0; 370 371 r = __write_initial_superblock(cmd); 372 if (r) 373 goto bad; 374 375 cmd->clean_when_opened = true; 376 return 0; 377 378bad: 379 dm_tm_destroy(cmd->tm); 380 dm_sm_destroy(cmd->metadata_sm); 381 382 return r; 383} 384 385static int __check_incompat_features(struct cache_disk_superblock *disk_super, 386 struct dm_cache_metadata *cmd) 387{ 388 uint32_t features; 389 390 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; 391 if (features) { 392 DMERR("could not access metadata due to unsupported optional features (%lx).", 393 (unsigned long)features); 394 return -EINVAL; 395 } 396 397 /* 398 * Check for read-only metadata to skip the following RDWR checks. 399 */ 400 if (get_disk_ro(cmd->bdev->bd_disk)) 401 return 0; 402 403 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; 404 if (features) { 405 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", 406 (unsigned long)features); 407 return -EINVAL; 408 } 409 410 return 0; 411} 412 413static int __open_metadata(struct dm_cache_metadata *cmd) 414{ 415 int r; 416 struct dm_block *sblock; 417 struct cache_disk_superblock *disk_super; 418 unsigned long sb_flags; 419 420 r = superblock_read_lock(cmd, &sblock); 421 if (r < 0) { 422 DMERR("couldn't read lock superblock"); 423 return r; 424 } 425 426 disk_super = dm_block_data(sblock); 427 428 r = __check_incompat_features(disk_super, cmd); 429 if (r < 0) 430 goto bad; 431 432 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 433 disk_super->metadata_space_map_root, 434 sizeof(disk_super->metadata_space_map_root), 435 &cmd->tm, &cmd->metadata_sm); 436 if (r < 0) { 437 DMERR("tm_open_with_sm failed"); 438 goto bad; 439 } 440 441 __setup_mapping_info(cmd); 442 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 443 sb_flags = le32_to_cpu(disk_super->flags); 444 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); 445 return dm_bm_unlock(sblock); 446 447bad: 448 dm_bm_unlock(sblock); 449 return r; 450} 451 452static int __open_or_format_metadata(struct dm_cache_metadata *cmd, 453 bool format_device) 454{ 455 int r; 456 bool unformatted = false; 457 458 r = __superblock_all_zeroes(cmd->bm, &unformatted); 459 if (r) 460 return r; 461 462 if (unformatted) 463 return format_device ? __format_metadata(cmd) : -EPERM; 464 465 return __open_metadata(cmd); 466} 467 468static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, 469 bool may_format_device) 470{ 471 int r; 472 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE, 473 CACHE_METADATA_CACHE_SIZE, 474 CACHE_MAX_CONCURRENT_LOCKS); 475 if (IS_ERR(cmd->bm)) { 476 DMERR("could not create block manager"); 477 return PTR_ERR(cmd->bm); 478 } 479 480 r = __open_or_format_metadata(cmd, may_format_device); 481 if (r) 482 dm_block_manager_destroy(cmd->bm); 483 484 return r; 485} 486 487static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) 488{ 489 dm_sm_destroy(cmd->metadata_sm); 490 dm_tm_destroy(cmd->tm); 491 dm_block_manager_destroy(cmd->bm); 492} 493 494typedef unsigned long (*flags_mutator)(unsigned long); 495 496static void update_flags(struct cache_disk_superblock *disk_super, 497 flags_mutator mutator) 498{ 499 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); 500 disk_super->flags = cpu_to_le32(sb_flags); 501} 502 503static unsigned long set_clean_shutdown(unsigned long flags) 504{ 505 set_bit(CLEAN_SHUTDOWN, &flags); 506 return flags; 507} 508 509static unsigned long clear_clean_shutdown(unsigned long flags) 510{ 511 clear_bit(CLEAN_SHUTDOWN, &flags); 512 return flags; 513} 514 515static void read_superblock_fields(struct dm_cache_metadata *cmd, 516 struct cache_disk_superblock *disk_super) 517{ 518 cmd->root = le64_to_cpu(disk_super->mapping_root); 519 cmd->hint_root = le64_to_cpu(disk_super->hint_root); 520 cmd->discard_root = le64_to_cpu(disk_super->discard_root); 521 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); 522 cmd->discard_nr_blocks = to_oblock(le64_to_cpu(disk_super->discard_nr_blocks)); 523 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); 524 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); 525 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); 526 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); 527 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); 528 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); 529 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); 530 531 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); 532 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); 533 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); 534 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); 535 536 cmd->changed = false; 537} 538 539/* 540 * The mutator updates the superblock flags. 541 */ 542static int __begin_transaction_flags(struct dm_cache_metadata *cmd, 543 flags_mutator mutator) 544{ 545 int r; 546 struct cache_disk_superblock *disk_super; 547 struct dm_block *sblock; 548 549 r = superblock_lock(cmd, &sblock); 550 if (r) 551 return r; 552 553 disk_super = dm_block_data(sblock); 554 update_flags(disk_super, mutator); 555 read_superblock_fields(cmd, disk_super); 556 dm_bm_unlock(sblock); 557 558 return dm_bm_flush(cmd->bm); 559} 560 561static int __begin_transaction(struct dm_cache_metadata *cmd) 562{ 563 int r; 564 struct cache_disk_superblock *disk_super; 565 struct dm_block *sblock; 566 567 /* 568 * We re-read the superblock every time. Shouldn't need to do this 569 * really. 570 */ 571 r = superblock_read_lock(cmd, &sblock); 572 if (r) 573 return r; 574 575 disk_super = dm_block_data(sblock); 576 read_superblock_fields(cmd, disk_super); 577 dm_bm_unlock(sblock); 578 579 return 0; 580} 581 582static int __commit_transaction(struct dm_cache_metadata *cmd, 583 flags_mutator mutator) 584{ 585 int r; 586 struct cache_disk_superblock *disk_super; 587 struct dm_block *sblock; 588 589 /* 590 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 591 */ 592 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 593 594 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 595 &cmd->discard_root); 596 if (r) 597 return r; 598 599 r = dm_tm_pre_commit(cmd->tm); 600 if (r < 0) 601 return r; 602 603 r = __save_sm_root(cmd); 604 if (r) 605 return r; 606 607 r = superblock_lock(cmd, &sblock); 608 if (r) 609 return r; 610 611 disk_super = dm_block_data(sblock); 612 613 if (mutator) 614 update_flags(disk_super, mutator); 615 616 disk_super->mapping_root = cpu_to_le64(cmd->root); 617 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 618 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 619 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 620 disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks)); 621 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 622 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 623 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); 624 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); 625 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); 626 627 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 628 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 629 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 630 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 631 __copy_sm_root(cmd, disk_super); 632 633 return dm_tm_commit(cmd->tm, sblock); 634} 635 636/*----------------------------------------------------------------*/ 637 638/* 639 * The mappings are held in a dm-array that has 64-bit values stored in 640 * little-endian format. The index is the cblock, the high 48bits of the 641 * value are the oblock and the low 16 bit the flags. 642 */ 643#define FLAGS_MASK ((1 << 16) - 1) 644 645static __le64 pack_value(dm_oblock_t block, unsigned flags) 646{ 647 uint64_t value = from_oblock(block); 648 value <<= 16; 649 value = value | (flags & FLAGS_MASK); 650 return cpu_to_le64(value); 651} 652 653static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 654{ 655 uint64_t value = le64_to_cpu(value_le); 656 uint64_t b = value >> 16; 657 *block = to_oblock(b); 658 *flags = value & FLAGS_MASK; 659} 660 661/*----------------------------------------------------------------*/ 662 663struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 664 sector_t data_block_size, 665 bool may_format_device, 666 size_t policy_hint_size) 667{ 668 int r; 669 struct dm_cache_metadata *cmd; 670 671 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 672 if (!cmd) { 673 DMERR("could not allocate metadata struct"); 674 return NULL; 675 } 676 677 init_rwsem(&cmd->root_lock); 678 cmd->bdev = bdev; 679 cmd->data_block_size = data_block_size; 680 cmd->cache_blocks = 0; 681 cmd->policy_hint_size = policy_hint_size; 682 cmd->changed = true; 683 684 r = __create_persistent_data_objects(cmd, may_format_device); 685 if (r) { 686 kfree(cmd); 687 return ERR_PTR(r); 688 } 689 690 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 691 if (r < 0) { 692 dm_cache_metadata_close(cmd); 693 return ERR_PTR(r); 694 } 695 696 return cmd; 697} 698 699void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 700{ 701 __destroy_persistent_data_objects(cmd); 702 kfree(cmd); 703} 704 705/* 706 * Checks that the given cache block is either unmapped or clean. 707 */ 708static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b, 709 bool *result) 710{ 711 int r; 712 __le64 value; 713 dm_oblock_t ob; 714 unsigned flags; 715 716 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value); 717 if (r) { 718 DMERR("block_unmapped_or_clean failed"); 719 return r; 720 } 721 722 unpack_value(value, &ob, &flags); 723 *result = !((flags & M_VALID) && (flags & M_DIRTY)); 724 725 return 0; 726} 727 728static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd, 729 dm_cblock_t begin, dm_cblock_t end, 730 bool *result) 731{ 732 int r; 733 *result = true; 734 735 while (begin != end) { 736 r = block_unmapped_or_clean(cmd, begin, result); 737 if (r) 738 return r; 739 740 if (!*result) { 741 DMERR("cache block %llu is dirty", 742 (unsigned long long) from_cblock(begin)); 743 return 0; 744 } 745 746 begin = to_cblock(from_cblock(begin) + 1); 747 } 748 749 return 0; 750} 751 752int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) 753{ 754 int r; 755 bool clean; 756 __le64 null_mapping = pack_value(0, 0); 757 758 down_write(&cmd->root_lock); 759 __dm_bless_for_disk(&null_mapping); 760 761 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) { 762 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean); 763 if (r) { 764 __dm_unbless_for_disk(&null_mapping); 765 goto out; 766 } 767 768 if (!clean) { 769 DMERR("unable to shrink cache due to dirty blocks"); 770 r = -EINVAL; 771 __dm_unbless_for_disk(&null_mapping); 772 goto out; 773 } 774 } 775 776 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), 777 from_cblock(new_cache_size), 778 &null_mapping, &cmd->root); 779 if (!r) 780 cmd->cache_blocks = new_cache_size; 781 cmd->changed = true; 782 783out: 784 up_write(&cmd->root_lock); 785 786 return r; 787} 788 789int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 790 sector_t discard_block_size, 791 dm_oblock_t new_nr_entries) 792{ 793 int r; 794 795 down_write(&cmd->root_lock); 796 r = dm_bitset_resize(&cmd->discard_info, 797 cmd->discard_root, 798 from_oblock(cmd->discard_nr_blocks), 799 from_oblock(new_nr_entries), 800 false, &cmd->discard_root); 801 if (!r) { 802 cmd->discard_block_size = discard_block_size; 803 cmd->discard_nr_blocks = new_nr_entries; 804 } 805 806 cmd->changed = true; 807 up_write(&cmd->root_lock); 808 809 return r; 810} 811 812static int __set_discard(struct dm_cache_metadata *cmd, dm_oblock_t b) 813{ 814 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, 815 from_oblock(b), &cmd->discard_root); 816} 817 818static int __clear_discard(struct dm_cache_metadata *cmd, dm_oblock_t b) 819{ 820 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, 821 from_oblock(b), &cmd->discard_root); 822} 823 824static int __is_discarded(struct dm_cache_metadata *cmd, dm_oblock_t b, 825 bool *is_discarded) 826{ 827 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root, 828 from_oblock(b), &cmd->discard_root, 829 is_discarded); 830} 831 832static int __discard(struct dm_cache_metadata *cmd, 833 dm_oblock_t dblock, bool discard) 834{ 835 int r; 836 837 r = (discard ? __set_discard : __clear_discard)(cmd, dblock); 838 if (r) 839 return r; 840 841 cmd->changed = true; 842 return 0; 843} 844 845int dm_cache_set_discard(struct dm_cache_metadata *cmd, 846 dm_oblock_t dblock, bool discard) 847{ 848 int r; 849 850 down_write(&cmd->root_lock); 851 r = __discard(cmd, dblock, discard); 852 up_write(&cmd->root_lock); 853 854 return r; 855} 856 857static int __load_discards(struct dm_cache_metadata *cmd, 858 load_discard_fn fn, void *context) 859{ 860 int r = 0; 861 dm_block_t b; 862 bool discard; 863 864 for (b = 0; b < from_oblock(cmd->discard_nr_blocks); b++) { 865 dm_oblock_t dblock = to_oblock(b); 866 867 if (cmd->clean_when_opened) { 868 r = __is_discarded(cmd, dblock, &discard); 869 if (r) 870 return r; 871 } else 872 discard = false; 873 874 r = fn(context, cmd->discard_block_size, dblock, discard); 875 if (r) 876 break; 877 } 878 879 return r; 880} 881 882int dm_cache_load_discards(struct dm_cache_metadata *cmd, 883 load_discard_fn fn, void *context) 884{ 885 int r; 886 887 down_read(&cmd->root_lock); 888 r = __load_discards(cmd, fn, context); 889 up_read(&cmd->root_lock); 890 891 return r; 892} 893 894dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd) 895{ 896 dm_cblock_t r; 897 898 down_read(&cmd->root_lock); 899 r = cmd->cache_blocks; 900 up_read(&cmd->root_lock); 901 902 return r; 903} 904 905static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 906{ 907 int r; 908 __le64 value = pack_value(0, 0); 909 910 __dm_bless_for_disk(&value); 911 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 912 &value, &cmd->root); 913 if (r) 914 return r; 915 916 cmd->changed = true; 917 return 0; 918} 919 920int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 921{ 922 int r; 923 924 down_write(&cmd->root_lock); 925 r = __remove(cmd, cblock); 926 up_write(&cmd->root_lock); 927 928 return r; 929} 930 931static int __insert(struct dm_cache_metadata *cmd, 932 dm_cblock_t cblock, dm_oblock_t oblock) 933{ 934 int r; 935 __le64 value = pack_value(oblock, M_VALID); 936 __dm_bless_for_disk(&value); 937 938 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 939 &value, &cmd->root); 940 if (r) 941 return r; 942 943 cmd->changed = true; 944 return 0; 945} 946 947int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, 948 dm_cblock_t cblock, dm_oblock_t oblock) 949{ 950 int r; 951 952 down_write(&cmd->root_lock); 953 r = __insert(cmd, cblock, oblock); 954 up_write(&cmd->root_lock); 955 956 return r; 957} 958 959struct thunk { 960 load_mapping_fn fn; 961 void *context; 962 963 struct dm_cache_metadata *cmd; 964 bool respect_dirty_flags; 965 bool hints_valid; 966}; 967 968static bool policy_unchanged(struct dm_cache_metadata *cmd, 969 struct dm_cache_policy *policy) 970{ 971 const char *policy_name = dm_cache_policy_get_name(policy); 972 const unsigned *policy_version = dm_cache_policy_get_version(policy); 973 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); 974 975 /* 976 * Ensure policy names match. 977 */ 978 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) 979 return false; 980 981 /* 982 * Ensure policy major versions match. 983 */ 984 if (cmd->policy_version[0] != policy_version[0]) 985 return false; 986 987 /* 988 * Ensure policy hint sizes match. 989 */ 990 if (cmd->policy_hint_size != policy_hint_size) 991 return false; 992 993 return true; 994} 995 996static bool hints_array_initialized(struct dm_cache_metadata *cmd) 997{ 998 return cmd->hint_root && cmd->policy_hint_size; 999} 1000 1001static bool hints_array_available(struct dm_cache_metadata *cmd, 1002 struct dm_cache_policy *policy) 1003{ 1004 return cmd->clean_when_opened && policy_unchanged(cmd, policy) && 1005 hints_array_initialized(cmd); 1006} 1007 1008static int __load_mapping(void *context, uint64_t cblock, void *leaf) 1009{ 1010 int r = 0; 1011 bool dirty; 1012 __le64 value; 1013 __le32 hint_value = 0; 1014 dm_oblock_t oblock; 1015 unsigned flags; 1016 struct thunk *thunk = context; 1017 struct dm_cache_metadata *cmd = thunk->cmd; 1018 1019 memcpy(&value, leaf, sizeof(value)); 1020 unpack_value(value, &oblock, &flags); 1021 1022 if (flags & M_VALID) { 1023 if (thunk->hints_valid) { 1024 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root, 1025 cblock, &hint_value); 1026 if (r && r != -ENODATA) 1027 return r; 1028 } 1029 1030 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true; 1031 r = thunk->fn(thunk->context, oblock, to_cblock(cblock), 1032 dirty, le32_to_cpu(hint_value), thunk->hints_valid); 1033 } 1034 1035 return r; 1036} 1037 1038static int __load_mappings(struct dm_cache_metadata *cmd, 1039 struct dm_cache_policy *policy, 1040 load_mapping_fn fn, void *context) 1041{ 1042 struct thunk thunk; 1043 1044 thunk.fn = fn; 1045 thunk.context = context; 1046 1047 thunk.cmd = cmd; 1048 thunk.respect_dirty_flags = cmd->clean_when_opened; 1049 thunk.hints_valid = hints_array_available(cmd, policy); 1050 1051 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk); 1052} 1053 1054int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 1055 struct dm_cache_policy *policy, 1056 load_mapping_fn fn, void *context) 1057{ 1058 int r; 1059 1060 down_read(&cmd->root_lock); 1061 r = __load_mappings(cmd, policy, fn, context); 1062 up_read(&cmd->root_lock); 1063 1064 return r; 1065} 1066 1067static int __dump_mapping(void *context, uint64_t cblock, void *leaf) 1068{ 1069 int r = 0; 1070 __le64 value; 1071 dm_oblock_t oblock; 1072 unsigned flags; 1073 1074 memcpy(&value, leaf, sizeof(value)); 1075 unpack_value(value, &oblock, &flags); 1076 1077 return r; 1078} 1079 1080static int __dump_mappings(struct dm_cache_metadata *cmd) 1081{ 1082 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); 1083} 1084 1085void dm_cache_dump(struct dm_cache_metadata *cmd) 1086{ 1087 down_read(&cmd->root_lock); 1088 __dump_mappings(cmd); 1089 up_read(&cmd->root_lock); 1090} 1091 1092int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) 1093{ 1094 int r; 1095 1096 down_read(&cmd->root_lock); 1097 r = cmd->changed; 1098 up_read(&cmd->root_lock); 1099 1100 return r; 1101} 1102 1103static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) 1104{ 1105 int r; 1106 unsigned flags; 1107 dm_oblock_t oblock; 1108 __le64 value; 1109 1110 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); 1111 if (r) 1112 return r; 1113 1114 unpack_value(value, &oblock, &flags); 1115 1116 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) 1117 /* nothing to be done */ 1118 return 0; 1119 1120 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); 1121 __dm_bless_for_disk(&value); 1122 1123 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1124 &value, &cmd->root); 1125 if (r) 1126 return r; 1127 1128 cmd->changed = true; 1129 return 0; 1130 1131} 1132 1133int dm_cache_set_dirty(struct dm_cache_metadata *cmd, 1134 dm_cblock_t cblock, bool dirty) 1135{ 1136 int r; 1137 1138 down_write(&cmd->root_lock); 1139 r = __dirty(cmd, cblock, dirty); 1140 up_write(&cmd->root_lock); 1141 1142 return r; 1143} 1144 1145void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 1146 struct dm_cache_statistics *stats) 1147{ 1148 down_read(&cmd->root_lock); 1149 *stats = cmd->stats; 1150 up_read(&cmd->root_lock); 1151} 1152 1153void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 1154 struct dm_cache_statistics *stats) 1155{ 1156 down_write(&cmd->root_lock); 1157 cmd->stats = *stats; 1158 up_write(&cmd->root_lock); 1159} 1160 1161int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) 1162{ 1163 int r; 1164 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1165 clear_clean_shutdown); 1166 1167 down_write(&cmd->root_lock); 1168 r = __commit_transaction(cmd, mutator); 1169 if (r) 1170 goto out; 1171 1172 r = __begin_transaction(cmd); 1173 1174out: 1175 up_write(&cmd->root_lock); 1176 return r; 1177} 1178 1179int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1180 dm_block_t *result) 1181{ 1182 int r = -EINVAL; 1183 1184 down_read(&cmd->root_lock); 1185 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1186 up_read(&cmd->root_lock); 1187 1188 return r; 1189} 1190 1191int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1192 dm_block_t *result) 1193{ 1194 int r = -EINVAL; 1195 1196 down_read(&cmd->root_lock); 1197 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1198 up_read(&cmd->root_lock); 1199 1200 return r; 1201} 1202 1203/*----------------------------------------------------------------*/ 1204 1205static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1206{ 1207 int r; 1208 __le32 value; 1209 size_t hint_size; 1210 const char *policy_name = dm_cache_policy_get_name(policy); 1211 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1212 1213 if (!policy_name[0] || 1214 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1215 return -EINVAL; 1216 1217 if (!policy_unchanged(cmd, policy)) { 1218 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1219 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); 1220 1221 hint_size = dm_cache_policy_get_hint_size(policy); 1222 if (!hint_size) 1223 return 0; /* short-circuit hints initialization */ 1224 cmd->policy_hint_size = hint_size; 1225 1226 if (cmd->hint_root) { 1227 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1228 if (r) 1229 return r; 1230 } 1231 1232 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root); 1233 if (r) 1234 return r; 1235 1236 value = cpu_to_le32(0); 1237 __dm_bless_for_disk(&value); 1238 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0, 1239 from_cblock(cmd->cache_blocks), 1240 &value, &cmd->hint_root); 1241 if (r) 1242 return r; 1243 } 1244 1245 return 0; 1246} 1247 1248int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1249{ 1250 int r; 1251 1252 down_write(&cmd->root_lock); 1253 r = begin_hints(cmd, policy); 1254 up_write(&cmd->root_lock); 1255 1256 return r; 1257} 1258 1259static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, 1260 uint32_t hint) 1261{ 1262 int r; 1263 __le32 value = cpu_to_le32(hint); 1264 __dm_bless_for_disk(&value); 1265 1266 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root, 1267 from_cblock(cblock), &value, &cmd->hint_root); 1268 cmd->changed = true; 1269 1270 return r; 1271} 1272 1273int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, 1274 uint32_t hint) 1275{ 1276 int r; 1277 1278 if (!hints_array_initialized(cmd)) 1279 return 0; 1280 1281 down_write(&cmd->root_lock); 1282 r = save_hint(cmd, cblock, hint); 1283 up_write(&cmd->root_lock); 1284 1285 return r; 1286} 1287 1288int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result) 1289{ 1290 return blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result); 1291} 1292