dm-cache-metadata.c revision ea2dd8c1ed0becee9812cf0840a9cd553ed398fe
1/* 2 * Copyright (C) 2012 Red Hat, Inc. 3 * 4 * This file is released under the GPL. 5 */ 6 7#include "dm-cache-metadata.h" 8 9#include "persistent-data/dm-array.h" 10#include "persistent-data/dm-bitset.h" 11#include "persistent-data/dm-space-map.h" 12#include "persistent-data/dm-space-map-disk.h" 13#include "persistent-data/dm-transaction-manager.h" 14 15#include <linux/device-mapper.h> 16 17/*----------------------------------------------------------------*/ 18 19#define DM_MSG_PREFIX "cache metadata" 20 21#define CACHE_SUPERBLOCK_MAGIC 06142003 22#define CACHE_SUPERBLOCK_LOCATION 0 23#define CACHE_VERSION 1 24#define CACHE_METADATA_CACHE_SIZE 64 25 26/* 27 * 3 for btree insert + 28 * 2 for btree lookup used within space map 29 */ 30#define CACHE_MAX_CONCURRENT_LOCKS 5 31#define SPACE_MAP_ROOT_SIZE 128 32 33enum superblock_flag_bits { 34 /* for spotting crashes that would invalidate the dirty bitset */ 35 CLEAN_SHUTDOWN, 36}; 37 38/* 39 * Each mapping from cache block -> origin block carries a set of flags. 40 */ 41enum mapping_bits { 42 /* 43 * A valid mapping. Because we're using an array we clear this 44 * flag for an non existant mapping. 45 */ 46 M_VALID = 1, 47 48 /* 49 * The data on the cache is different from that on the origin. 50 */ 51 M_DIRTY = 2 52}; 53 54struct cache_disk_superblock { 55 __le32 csum; 56 __le32 flags; 57 __le64 blocknr; 58 59 __u8 uuid[16]; 60 __le64 magic; 61 __le32 version; 62 63 __u8 policy_name[CACHE_POLICY_NAME_SIZE]; 64 __le32 policy_hint_size; 65 66 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 67 __le64 mapping_root; 68 __le64 hint_root; 69 70 __le64 discard_root; 71 __le64 discard_block_size; 72 __le64 discard_nr_blocks; 73 74 __le32 data_block_size; 75 __le32 metadata_block_size; 76 __le32 cache_blocks; 77 78 __le32 compat_flags; 79 __le32 compat_ro_flags; 80 __le32 incompat_flags; 81 82 __le32 read_hits; 83 __le32 read_misses; 84 __le32 write_hits; 85 __le32 write_misses; 86 87 __le32 policy_version[CACHE_POLICY_VERSION_SIZE]; 88} __packed; 89 90struct dm_cache_metadata { 91 struct block_device *bdev; 92 struct dm_block_manager *bm; 93 struct dm_space_map *metadata_sm; 94 struct dm_transaction_manager *tm; 95 96 struct dm_array_info info; 97 struct dm_array_info hint_info; 98 struct dm_disk_bitset discard_info; 99 100 struct rw_semaphore root_lock; 101 dm_block_t root; 102 dm_block_t hint_root; 103 dm_block_t discard_root; 104 105 sector_t discard_block_size; 106 dm_dblock_t discard_nr_blocks; 107 108 sector_t data_block_size; 109 dm_cblock_t cache_blocks; 110 bool changed:1; 111 bool clean_when_opened:1; 112 113 char policy_name[CACHE_POLICY_NAME_SIZE]; 114 unsigned policy_version[CACHE_POLICY_VERSION_SIZE]; 115 size_t policy_hint_size; 116 struct dm_cache_statistics stats; 117}; 118 119/*------------------------------------------------------------------- 120 * superblock validator 121 *-----------------------------------------------------------------*/ 122 123#define SUPERBLOCK_CSUM_XOR 9031977 124 125static void sb_prepare_for_write(struct dm_block_validator *v, 126 struct dm_block *b, 127 size_t sb_block_size) 128{ 129 struct cache_disk_superblock *disk_super = dm_block_data(b); 130 131 disk_super->blocknr = cpu_to_le64(dm_block_location(b)); 132 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 133 sb_block_size - sizeof(__le32), 134 SUPERBLOCK_CSUM_XOR)); 135} 136 137static int sb_check(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 __le32 csum_le; 143 144 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { 145 DMERR("sb_check failed: blocknr %llu: wanted %llu", 146 le64_to_cpu(disk_super->blocknr), 147 (unsigned long long)dm_block_location(b)); 148 return -ENOTBLK; 149 } 150 151 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { 152 DMERR("sb_check failed: magic %llu: wanted %llu", 153 le64_to_cpu(disk_super->magic), 154 (unsigned long long)CACHE_SUPERBLOCK_MAGIC); 155 return -EILSEQ; 156 } 157 158 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 159 sb_block_size - sizeof(__le32), 160 SUPERBLOCK_CSUM_XOR)); 161 if (csum_le != disk_super->csum) { 162 DMERR("sb_check failed: csum %u: wanted %u", 163 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); 164 return -EILSEQ; 165 } 166 167 return 0; 168} 169 170static struct dm_block_validator sb_validator = { 171 .name = "superblock", 172 .prepare_for_write = sb_prepare_for_write, 173 .check = sb_check 174}; 175 176/*----------------------------------------------------------------*/ 177 178static int superblock_read_lock(struct dm_cache_metadata *cmd, 179 struct dm_block **sblock) 180{ 181 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 182 &sb_validator, sblock); 183} 184 185static int superblock_lock_zero(struct dm_cache_metadata *cmd, 186 struct dm_block **sblock) 187{ 188 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 189 &sb_validator, sblock); 190} 191 192static int superblock_lock(struct dm_cache_metadata *cmd, 193 struct dm_block **sblock) 194{ 195 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 196 &sb_validator, sblock); 197} 198 199/*----------------------------------------------------------------*/ 200 201static int __superblock_all_zeroes(struct dm_block_manager *bm, int *result) 202{ 203 int r; 204 unsigned i; 205 struct dm_block *b; 206 __le64 *data_le, zero = cpu_to_le64(0); 207 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 208 209 /* 210 * We can't use a validator here - it may be all zeroes. 211 */ 212 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); 213 if (r) 214 return r; 215 216 data_le = dm_block_data(b); 217 *result = 1; 218 for (i = 0; i < sb_block_size; i++) { 219 if (data_le[i] != zero) { 220 *result = 0; 221 break; 222 } 223 } 224 225 return dm_bm_unlock(b); 226} 227 228static void __setup_mapping_info(struct dm_cache_metadata *cmd) 229{ 230 struct dm_btree_value_type vt; 231 232 vt.context = NULL; 233 vt.size = sizeof(__le64); 234 vt.inc = NULL; 235 vt.dec = NULL; 236 vt.equal = NULL; 237 dm_array_info_init(&cmd->info, cmd->tm, &vt); 238 239 if (cmd->policy_hint_size) { 240 vt.size = sizeof(__le32); 241 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); 242 } 243} 244 245static int __write_initial_superblock(struct dm_cache_metadata *cmd) 246{ 247 int r; 248 struct dm_block *sblock; 249 size_t metadata_len; 250 struct cache_disk_superblock *disk_super; 251 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT; 252 253 /* FIXME: see if we can lose the max sectors limit */ 254 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) 255 bdev_size = DM_CACHE_METADATA_MAX_SECTORS; 256 257 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 258 if (r < 0) 259 return r; 260 261 r = dm_tm_pre_commit(cmd->tm); 262 if (r < 0) 263 return r; 264 265 r = superblock_lock_zero(cmd, &sblock); 266 if (r) 267 return r; 268 269 disk_super = dm_block_data(sblock); 270 disk_super->flags = 0; 271 memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); 272 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); 273 disk_super->version = cpu_to_le32(CACHE_VERSION); 274 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); 275 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); 276 disk_super->policy_hint_size = 0; 277 278 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, 279 metadata_len); 280 if (r < 0) 281 goto bad_locked; 282 283 disk_super->mapping_root = cpu_to_le64(cmd->root); 284 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 285 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 286 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 287 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 288 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); 289 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); 290 disk_super->cache_blocks = cpu_to_le32(0); 291 292 disk_super->read_hits = cpu_to_le32(0); 293 disk_super->read_misses = cpu_to_le32(0); 294 disk_super->write_hits = cpu_to_le32(0); 295 disk_super->write_misses = cpu_to_le32(0); 296 297 return dm_tm_commit(cmd->tm, sblock); 298 299bad_locked: 300 dm_bm_unlock(sblock); 301 return r; 302} 303 304static int __format_metadata(struct dm_cache_metadata *cmd) 305{ 306 int r; 307 308 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 309 &cmd->tm, &cmd->metadata_sm); 310 if (r < 0) { 311 DMERR("tm_create_with_sm failed"); 312 return r; 313 } 314 315 __setup_mapping_info(cmd); 316 317 r = dm_array_empty(&cmd->info, &cmd->root); 318 if (r < 0) 319 goto bad; 320 321 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 322 323 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); 324 if (r < 0) 325 goto bad; 326 327 cmd->discard_block_size = 0; 328 cmd->discard_nr_blocks = 0; 329 330 r = __write_initial_superblock(cmd); 331 if (r) 332 goto bad; 333 334 cmd->clean_when_opened = true; 335 return 0; 336 337bad: 338 dm_tm_destroy(cmd->tm); 339 dm_sm_destroy(cmd->metadata_sm); 340 341 return r; 342} 343 344static int __check_incompat_features(struct cache_disk_superblock *disk_super, 345 struct dm_cache_metadata *cmd) 346{ 347 uint32_t features; 348 349 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; 350 if (features) { 351 DMERR("could not access metadata due to unsupported optional features (%lx).", 352 (unsigned long)features); 353 return -EINVAL; 354 } 355 356 /* 357 * Check for read-only metadata to skip the following RDWR checks. 358 */ 359 if (get_disk_ro(cmd->bdev->bd_disk)) 360 return 0; 361 362 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; 363 if (features) { 364 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", 365 (unsigned long)features); 366 return -EINVAL; 367 } 368 369 return 0; 370} 371 372static int __open_metadata(struct dm_cache_metadata *cmd) 373{ 374 int r; 375 struct dm_block *sblock; 376 struct cache_disk_superblock *disk_super; 377 unsigned long sb_flags; 378 379 r = superblock_read_lock(cmd, &sblock); 380 if (r < 0) { 381 DMERR("couldn't read lock superblock"); 382 return r; 383 } 384 385 disk_super = dm_block_data(sblock); 386 387 r = __check_incompat_features(disk_super, cmd); 388 if (r < 0) 389 goto bad; 390 391 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 392 disk_super->metadata_space_map_root, 393 sizeof(disk_super->metadata_space_map_root), 394 &cmd->tm, &cmd->metadata_sm); 395 if (r < 0) { 396 DMERR("tm_open_with_sm failed"); 397 goto bad; 398 } 399 400 __setup_mapping_info(cmd); 401 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 402 sb_flags = le32_to_cpu(disk_super->flags); 403 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); 404 return dm_bm_unlock(sblock); 405 406bad: 407 dm_bm_unlock(sblock); 408 return r; 409} 410 411static int __open_or_format_metadata(struct dm_cache_metadata *cmd, 412 bool format_device) 413{ 414 int r, unformatted; 415 416 r = __superblock_all_zeroes(cmd->bm, &unformatted); 417 if (r) 418 return r; 419 420 if (unformatted) 421 return format_device ? __format_metadata(cmd) : -EPERM; 422 423 return __open_metadata(cmd); 424} 425 426static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, 427 bool may_format_device) 428{ 429 int r; 430 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE, 431 CACHE_METADATA_CACHE_SIZE, 432 CACHE_MAX_CONCURRENT_LOCKS); 433 if (IS_ERR(cmd->bm)) { 434 DMERR("could not create block manager"); 435 return PTR_ERR(cmd->bm); 436 } 437 438 r = __open_or_format_metadata(cmd, may_format_device); 439 if (r) 440 dm_block_manager_destroy(cmd->bm); 441 442 return r; 443} 444 445static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) 446{ 447 dm_sm_destroy(cmd->metadata_sm); 448 dm_tm_destroy(cmd->tm); 449 dm_block_manager_destroy(cmd->bm); 450} 451 452typedef unsigned long (*flags_mutator)(unsigned long); 453 454static void update_flags(struct cache_disk_superblock *disk_super, 455 flags_mutator mutator) 456{ 457 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); 458 disk_super->flags = cpu_to_le32(sb_flags); 459} 460 461static unsigned long set_clean_shutdown(unsigned long flags) 462{ 463 set_bit(CLEAN_SHUTDOWN, &flags); 464 return flags; 465} 466 467static unsigned long clear_clean_shutdown(unsigned long flags) 468{ 469 clear_bit(CLEAN_SHUTDOWN, &flags); 470 return flags; 471} 472 473static void read_superblock_fields(struct dm_cache_metadata *cmd, 474 struct cache_disk_superblock *disk_super) 475{ 476 cmd->root = le64_to_cpu(disk_super->mapping_root); 477 cmd->hint_root = le64_to_cpu(disk_super->hint_root); 478 cmd->discard_root = le64_to_cpu(disk_super->discard_root); 479 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); 480 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); 481 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); 482 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); 483 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); 484 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); 485 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); 486 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); 487 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); 488 489 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); 490 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); 491 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); 492 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); 493 494 cmd->changed = false; 495} 496 497/* 498 * The mutator updates the superblock flags. 499 */ 500static int __begin_transaction_flags(struct dm_cache_metadata *cmd, 501 flags_mutator mutator) 502{ 503 int r; 504 struct cache_disk_superblock *disk_super; 505 struct dm_block *sblock; 506 507 r = superblock_lock(cmd, &sblock); 508 if (r) 509 return r; 510 511 disk_super = dm_block_data(sblock); 512 update_flags(disk_super, mutator); 513 read_superblock_fields(cmd, disk_super); 514 515 return dm_bm_flush_and_unlock(cmd->bm, sblock); 516} 517 518static int __begin_transaction(struct dm_cache_metadata *cmd) 519{ 520 int r; 521 struct cache_disk_superblock *disk_super; 522 struct dm_block *sblock; 523 524 /* 525 * We re-read the superblock every time. Shouldn't need to do this 526 * really. 527 */ 528 r = superblock_read_lock(cmd, &sblock); 529 if (r) 530 return r; 531 532 disk_super = dm_block_data(sblock); 533 read_superblock_fields(cmd, disk_super); 534 dm_bm_unlock(sblock); 535 536 return 0; 537} 538 539static int __commit_transaction(struct dm_cache_metadata *cmd, 540 flags_mutator mutator) 541{ 542 int r; 543 size_t metadata_len; 544 struct cache_disk_superblock *disk_super; 545 struct dm_block *sblock; 546 547 /* 548 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 549 */ 550 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 551 552 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 553 &cmd->discard_root); 554 if (r) 555 return r; 556 557 r = dm_tm_pre_commit(cmd->tm); 558 if (r < 0) 559 return r; 560 561 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 562 if (r < 0) 563 return r; 564 565 r = superblock_lock(cmd, &sblock); 566 if (r) 567 return r; 568 569 disk_super = dm_block_data(sblock); 570 571 if (mutator) 572 update_flags(disk_super, mutator); 573 574 disk_super->mapping_root = cpu_to_le64(cmd->root); 575 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 576 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 577 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 578 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 579 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 580 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 581 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); 582 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); 583 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); 584 585 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 586 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 587 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 588 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 589 590 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, 591 metadata_len); 592 if (r < 0) { 593 dm_bm_unlock(sblock); 594 return r; 595 } 596 597 return dm_tm_commit(cmd->tm, sblock); 598} 599 600/*----------------------------------------------------------------*/ 601 602/* 603 * The mappings are held in a dm-array that has 64-bit values stored in 604 * little-endian format. The index is the cblock, the high 48bits of the 605 * value are the oblock and the low 16 bit the flags. 606 */ 607#define FLAGS_MASK ((1 << 16) - 1) 608 609static __le64 pack_value(dm_oblock_t block, unsigned flags) 610{ 611 uint64_t value = from_oblock(block); 612 value <<= 16; 613 value = value | (flags & FLAGS_MASK); 614 return cpu_to_le64(value); 615} 616 617static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 618{ 619 uint64_t value = le64_to_cpu(value_le); 620 uint64_t b = value >> 16; 621 *block = to_oblock(b); 622 *flags = value & FLAGS_MASK; 623} 624 625/*----------------------------------------------------------------*/ 626 627struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 628 sector_t data_block_size, 629 bool may_format_device, 630 size_t policy_hint_size) 631{ 632 int r; 633 struct dm_cache_metadata *cmd; 634 635 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 636 if (!cmd) { 637 DMERR("could not allocate metadata struct"); 638 return NULL; 639 } 640 641 init_rwsem(&cmd->root_lock); 642 cmd->bdev = bdev; 643 cmd->data_block_size = data_block_size; 644 cmd->cache_blocks = 0; 645 cmd->policy_hint_size = policy_hint_size; 646 cmd->changed = true; 647 648 r = __create_persistent_data_objects(cmd, may_format_device); 649 if (r) { 650 kfree(cmd); 651 return ERR_PTR(r); 652 } 653 654 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 655 if (r < 0) { 656 dm_cache_metadata_close(cmd); 657 return ERR_PTR(r); 658 } 659 660 return cmd; 661} 662 663void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 664{ 665 __destroy_persistent_data_objects(cmd); 666 kfree(cmd); 667} 668 669int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) 670{ 671 int r; 672 __le64 null_mapping = pack_value(0, 0); 673 674 down_write(&cmd->root_lock); 675 __dm_bless_for_disk(&null_mapping); 676 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), 677 from_cblock(new_cache_size), 678 &null_mapping, &cmd->root); 679 if (!r) 680 cmd->cache_blocks = new_cache_size; 681 cmd->changed = true; 682 up_write(&cmd->root_lock); 683 684 return r; 685} 686 687int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 688 sector_t discard_block_size, 689 dm_dblock_t new_nr_entries) 690{ 691 int r; 692 693 down_write(&cmd->root_lock); 694 r = dm_bitset_resize(&cmd->discard_info, 695 cmd->discard_root, 696 from_dblock(cmd->discard_nr_blocks), 697 from_dblock(new_nr_entries), 698 false, &cmd->discard_root); 699 if (!r) { 700 cmd->discard_block_size = discard_block_size; 701 cmd->discard_nr_blocks = new_nr_entries; 702 } 703 704 cmd->changed = true; 705 up_write(&cmd->root_lock); 706 707 return r; 708} 709 710static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 711{ 712 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, 713 from_dblock(b), &cmd->discard_root); 714} 715 716static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 717{ 718 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, 719 from_dblock(b), &cmd->discard_root); 720} 721 722static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b, 723 bool *is_discarded) 724{ 725 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root, 726 from_dblock(b), &cmd->discard_root, 727 is_discarded); 728} 729 730static int __discard(struct dm_cache_metadata *cmd, 731 dm_dblock_t dblock, bool discard) 732{ 733 int r; 734 735 r = (discard ? __set_discard : __clear_discard)(cmd, dblock); 736 if (r) 737 return r; 738 739 cmd->changed = true; 740 return 0; 741} 742 743int dm_cache_set_discard(struct dm_cache_metadata *cmd, 744 dm_dblock_t dblock, bool discard) 745{ 746 int r; 747 748 down_write(&cmd->root_lock); 749 r = __discard(cmd, dblock, discard); 750 up_write(&cmd->root_lock); 751 752 return r; 753} 754 755static int __load_discards(struct dm_cache_metadata *cmd, 756 load_discard_fn fn, void *context) 757{ 758 int r = 0; 759 dm_block_t b; 760 bool discard; 761 762 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { 763 dm_dblock_t dblock = to_dblock(b); 764 765 if (cmd->clean_when_opened) { 766 r = __is_discarded(cmd, dblock, &discard); 767 if (r) 768 return r; 769 } else 770 discard = false; 771 772 r = fn(context, cmd->discard_block_size, dblock, discard); 773 if (r) 774 break; 775 } 776 777 return r; 778} 779 780int dm_cache_load_discards(struct dm_cache_metadata *cmd, 781 load_discard_fn fn, void *context) 782{ 783 int r; 784 785 down_read(&cmd->root_lock); 786 r = __load_discards(cmd, fn, context); 787 up_read(&cmd->root_lock); 788 789 return r; 790} 791 792dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd) 793{ 794 dm_cblock_t r; 795 796 down_read(&cmd->root_lock); 797 r = cmd->cache_blocks; 798 up_read(&cmd->root_lock); 799 800 return r; 801} 802 803static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 804{ 805 int r; 806 __le64 value = pack_value(0, 0); 807 808 __dm_bless_for_disk(&value); 809 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 810 &value, &cmd->root); 811 if (r) 812 return r; 813 814 cmd->changed = true; 815 return 0; 816} 817 818int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 819{ 820 int r; 821 822 down_write(&cmd->root_lock); 823 r = __remove(cmd, cblock); 824 up_write(&cmd->root_lock); 825 826 return r; 827} 828 829static int __insert(struct dm_cache_metadata *cmd, 830 dm_cblock_t cblock, dm_oblock_t oblock) 831{ 832 int r; 833 __le64 value = pack_value(oblock, M_VALID); 834 __dm_bless_for_disk(&value); 835 836 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 837 &value, &cmd->root); 838 if (r) 839 return r; 840 841 cmd->changed = true; 842 return 0; 843} 844 845int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, 846 dm_cblock_t cblock, dm_oblock_t oblock) 847{ 848 int r; 849 850 down_write(&cmd->root_lock); 851 r = __insert(cmd, cblock, oblock); 852 up_write(&cmd->root_lock); 853 854 return r; 855} 856 857struct thunk { 858 load_mapping_fn fn; 859 void *context; 860 861 struct dm_cache_metadata *cmd; 862 bool respect_dirty_flags; 863 bool hints_valid; 864}; 865 866static bool policy_unchanged(struct dm_cache_metadata *cmd, 867 struct dm_cache_policy *policy) 868{ 869 const char *policy_name = dm_cache_policy_get_name(policy); 870 const unsigned *policy_version = dm_cache_policy_get_version(policy); 871 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); 872 873 /* 874 * Ensure policy names match. 875 */ 876 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) 877 return false; 878 879 /* 880 * Ensure policy major versions match. 881 */ 882 if (cmd->policy_version[0] != policy_version[0]) 883 return false; 884 885 /* 886 * Ensure policy hint sizes match. 887 */ 888 if (cmd->policy_hint_size != policy_hint_size) 889 return false; 890 891 return true; 892} 893 894static bool hints_array_initialized(struct dm_cache_metadata *cmd) 895{ 896 return cmd->hint_root && cmd->policy_hint_size; 897} 898 899static bool hints_array_available(struct dm_cache_metadata *cmd, 900 struct dm_cache_policy *policy) 901{ 902 return cmd->clean_when_opened && policy_unchanged(cmd, policy) && 903 hints_array_initialized(cmd); 904} 905 906static int __load_mapping(void *context, uint64_t cblock, void *leaf) 907{ 908 int r = 0; 909 bool dirty; 910 __le64 value; 911 __le32 hint_value = 0; 912 dm_oblock_t oblock; 913 unsigned flags; 914 struct thunk *thunk = context; 915 struct dm_cache_metadata *cmd = thunk->cmd; 916 917 memcpy(&value, leaf, sizeof(value)); 918 unpack_value(value, &oblock, &flags); 919 920 if (flags & M_VALID) { 921 if (thunk->hints_valid) { 922 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root, 923 cblock, &hint_value); 924 if (r && r != -ENODATA) 925 return r; 926 } 927 928 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true; 929 r = thunk->fn(thunk->context, oblock, to_cblock(cblock), 930 dirty, le32_to_cpu(hint_value), thunk->hints_valid); 931 } 932 933 return r; 934} 935 936static int __load_mappings(struct dm_cache_metadata *cmd, 937 struct dm_cache_policy *policy, 938 load_mapping_fn fn, void *context) 939{ 940 struct thunk thunk; 941 942 thunk.fn = fn; 943 thunk.context = context; 944 945 thunk.cmd = cmd; 946 thunk.respect_dirty_flags = cmd->clean_when_opened; 947 thunk.hints_valid = hints_array_available(cmd, policy); 948 949 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk); 950} 951 952int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 953 struct dm_cache_policy *policy, 954 load_mapping_fn fn, void *context) 955{ 956 int r; 957 958 down_read(&cmd->root_lock); 959 r = __load_mappings(cmd, policy, fn, context); 960 up_read(&cmd->root_lock); 961 962 return r; 963} 964 965static int __dump_mapping(void *context, uint64_t cblock, void *leaf) 966{ 967 int r = 0; 968 __le64 value; 969 dm_oblock_t oblock; 970 unsigned flags; 971 972 memcpy(&value, leaf, sizeof(value)); 973 unpack_value(value, &oblock, &flags); 974 975 return r; 976} 977 978static int __dump_mappings(struct dm_cache_metadata *cmd) 979{ 980 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); 981} 982 983void dm_cache_dump(struct dm_cache_metadata *cmd) 984{ 985 down_read(&cmd->root_lock); 986 __dump_mappings(cmd); 987 up_read(&cmd->root_lock); 988} 989 990int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) 991{ 992 int r; 993 994 down_read(&cmd->root_lock); 995 r = cmd->changed; 996 up_read(&cmd->root_lock); 997 998 return r; 999} 1000 1001static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) 1002{ 1003 int r; 1004 unsigned flags; 1005 dm_oblock_t oblock; 1006 __le64 value; 1007 1008 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); 1009 if (r) 1010 return r; 1011 1012 unpack_value(value, &oblock, &flags); 1013 1014 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) 1015 /* nothing to be done */ 1016 return 0; 1017 1018 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); 1019 __dm_bless_for_disk(&value); 1020 1021 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1022 &value, &cmd->root); 1023 if (r) 1024 return r; 1025 1026 cmd->changed = true; 1027 return 0; 1028 1029} 1030 1031int dm_cache_set_dirty(struct dm_cache_metadata *cmd, 1032 dm_cblock_t cblock, bool dirty) 1033{ 1034 int r; 1035 1036 down_write(&cmd->root_lock); 1037 r = __dirty(cmd, cblock, dirty); 1038 up_write(&cmd->root_lock); 1039 1040 return r; 1041} 1042 1043void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 1044 struct dm_cache_statistics *stats) 1045{ 1046 down_read(&cmd->root_lock); 1047 memcpy(stats, &cmd->stats, sizeof(*stats)); 1048 up_read(&cmd->root_lock); 1049} 1050 1051void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 1052 struct dm_cache_statistics *stats) 1053{ 1054 down_write(&cmd->root_lock); 1055 memcpy(&cmd->stats, stats, sizeof(*stats)); 1056 up_write(&cmd->root_lock); 1057} 1058 1059int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) 1060{ 1061 int r; 1062 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1063 clear_clean_shutdown); 1064 1065 down_write(&cmd->root_lock); 1066 r = __commit_transaction(cmd, mutator); 1067 if (r) 1068 goto out; 1069 1070 r = __begin_transaction(cmd); 1071 1072out: 1073 up_write(&cmd->root_lock); 1074 return r; 1075} 1076 1077int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1078 dm_block_t *result) 1079{ 1080 int r = -EINVAL; 1081 1082 down_read(&cmd->root_lock); 1083 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1084 up_read(&cmd->root_lock); 1085 1086 return r; 1087} 1088 1089int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1090 dm_block_t *result) 1091{ 1092 int r = -EINVAL; 1093 1094 down_read(&cmd->root_lock); 1095 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1096 up_read(&cmd->root_lock); 1097 1098 return r; 1099} 1100 1101/*----------------------------------------------------------------*/ 1102 1103static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1104{ 1105 int r; 1106 __le32 value; 1107 size_t hint_size; 1108 const char *policy_name = dm_cache_policy_get_name(policy); 1109 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1110 1111 if (!policy_name[0] || 1112 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1113 return -EINVAL; 1114 1115 if (!policy_unchanged(cmd, policy)) { 1116 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1117 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); 1118 1119 hint_size = dm_cache_policy_get_hint_size(policy); 1120 if (!hint_size) 1121 return 0; /* short-circuit hints initialization */ 1122 cmd->policy_hint_size = hint_size; 1123 1124 if (cmd->hint_root) { 1125 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1126 if (r) 1127 return r; 1128 } 1129 1130 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root); 1131 if (r) 1132 return r; 1133 1134 value = cpu_to_le32(0); 1135 __dm_bless_for_disk(&value); 1136 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0, 1137 from_cblock(cmd->cache_blocks), 1138 &value, &cmd->hint_root); 1139 if (r) 1140 return r; 1141 } 1142 1143 return 0; 1144} 1145 1146int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1147{ 1148 int r; 1149 1150 down_write(&cmd->root_lock); 1151 r = begin_hints(cmd, policy); 1152 up_write(&cmd->root_lock); 1153 1154 return r; 1155} 1156 1157static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, 1158 uint32_t hint) 1159{ 1160 int r; 1161 __le32 value = cpu_to_le32(hint); 1162 __dm_bless_for_disk(&value); 1163 1164 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root, 1165 from_cblock(cblock), &value, &cmd->hint_root); 1166 cmd->changed = true; 1167 1168 return r; 1169} 1170 1171int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, 1172 uint32_t hint) 1173{ 1174 int r; 1175 1176 if (!hints_array_initialized(cmd)) 1177 return 0; 1178 1179 down_write(&cmd->root_lock); 1180 r = save_hint(cmd, cblock, hint); 1181 up_write(&cmd->root_lock); 1182 1183 return r; 1184} 1185