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 2 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 39 enum superblock_flag_bits { 40 /* for spotting crashes that would invalidate the dirty bitset */ 41 CLEAN_SHUTDOWN, 42 /* metadata must be checked using the tools */ 43 NEEDS_CHECK, 44 }; 45 46 /* 47 * Each mapping from cache block -> origin block carries a set of flags. 48 */ 49 enum mapping_bits { 50 /* 51 * A valid mapping. Because we're using an array we clear this 52 * flag for an non existant mapping. 53 */ 54 M_VALID = 1, 55 56 /* 57 * The data on the cache is different from that on the origin. 58 * This flag is only used by metadata format 1. 59 */ 60 M_DIRTY = 2 61 }; 62 63 struct cache_disk_superblock { 64 __le32 csum; 65 __le32 flags; 66 __le64 blocknr; 67 68 __u8 uuid[16]; 69 __le64 magic; 70 __le32 version; 71 72 __u8 policy_name[CACHE_POLICY_NAME_SIZE]; 73 __le32 policy_hint_size; 74 75 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 76 __le64 mapping_root; 77 __le64 hint_root; 78 79 __le64 discard_root; 80 __le64 discard_block_size; 81 __le64 discard_nr_blocks; 82 83 __le32 data_block_size; 84 __le32 metadata_block_size; 85 __le32 cache_blocks; 86 87 __le32 compat_flags; 88 __le32 compat_ro_flags; 89 __le32 incompat_flags; 90 91 __le32 read_hits; 92 __le32 read_misses; 93 __le32 write_hits; 94 __le32 write_misses; 95 96 __le32 policy_version[CACHE_POLICY_VERSION_SIZE]; 97 98 /* 99 * Metadata format 2 fields. 100 */ 101 __le64 dirty_root; 102 } __packed; 103 104 struct dm_cache_metadata { 105 atomic_t ref_count; 106 struct list_head list; 107 108 unsigned version; 109 struct block_device *bdev; 110 struct dm_block_manager *bm; 111 struct dm_space_map *metadata_sm; 112 struct dm_transaction_manager *tm; 113 114 struct dm_array_info info; 115 struct dm_array_info hint_info; 116 struct dm_disk_bitset discard_info; 117 118 struct rw_semaphore root_lock; 119 unsigned long flags; 120 dm_block_t root; 121 dm_block_t hint_root; 122 dm_block_t discard_root; 123 124 sector_t discard_block_size; 125 dm_dblock_t discard_nr_blocks; 126 127 sector_t data_block_size; 128 dm_cblock_t cache_blocks; 129 bool changed:1; 130 bool clean_when_opened:1; 131 132 char policy_name[CACHE_POLICY_NAME_SIZE]; 133 unsigned policy_version[CACHE_POLICY_VERSION_SIZE]; 134 size_t policy_hint_size; 135 struct dm_cache_statistics stats; 136 137 /* 138 * Reading the space map root can fail, so we read it into this 139 * buffer before the superblock is locked and updated. 140 */ 141 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 142 143 /* 144 * Set if a transaction has to be aborted but the attempt to roll 145 * back to the previous (good) transaction failed. The only 146 * metadata operation permissible in this state is the closing of 147 * the device. 148 */ 149 bool fail_io:1; 150 151 /* 152 * Metadata format 2 fields. 153 */ 154 dm_block_t dirty_root; 155 struct dm_disk_bitset dirty_info; 156 157 /* 158 * These structures are used when loading metadata. They're too 159 * big to put on the stack. 160 */ 161 struct dm_array_cursor mapping_cursor; 162 struct dm_array_cursor hint_cursor; 163 struct dm_bitset_cursor dirty_cursor; 164 }; 165 166 /*------------------------------------------------------------------- 167 * superblock validator 168 *-----------------------------------------------------------------*/ 169 170 #define SUPERBLOCK_CSUM_XOR 9031977 171 172 static void sb_prepare_for_write(struct dm_block_validator *v, 173 struct dm_block *b, 174 size_t sb_block_size) 175 { 176 struct cache_disk_superblock *disk_super = dm_block_data(b); 177 178 disk_super->blocknr = cpu_to_le64(dm_block_location(b)); 179 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 180 sb_block_size - sizeof(__le32), 181 SUPERBLOCK_CSUM_XOR)); 182 } 183 184 static int check_metadata_version(struct cache_disk_superblock *disk_super) 185 { 186 uint32_t metadata_version = le32_to_cpu(disk_super->version); 187 188 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) { 189 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.", 190 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION); 191 return -EINVAL; 192 } 193 194 return 0; 195 } 196 197 static int sb_check(struct dm_block_validator *v, 198 struct dm_block *b, 199 size_t sb_block_size) 200 { 201 struct cache_disk_superblock *disk_super = dm_block_data(b); 202 __le32 csum_le; 203 204 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { 205 DMERR("sb_check failed: blocknr %llu: wanted %llu", 206 le64_to_cpu(disk_super->blocknr), 207 (unsigned long long)dm_block_location(b)); 208 return -ENOTBLK; 209 } 210 211 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { 212 DMERR("sb_check failed: magic %llu: wanted %llu", 213 le64_to_cpu(disk_super->magic), 214 (unsigned long long)CACHE_SUPERBLOCK_MAGIC); 215 return -EILSEQ; 216 } 217 218 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 219 sb_block_size - sizeof(__le32), 220 SUPERBLOCK_CSUM_XOR)); 221 if (csum_le != disk_super->csum) { 222 DMERR("sb_check failed: csum %u: wanted %u", 223 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); 224 return -EILSEQ; 225 } 226 227 return check_metadata_version(disk_super); 228 } 229 230 static struct dm_block_validator sb_validator = { 231 .name = "superblock", 232 .prepare_for_write = sb_prepare_for_write, 233 .check = sb_check 234 }; 235 236 /*----------------------------------------------------------------*/ 237 238 static int superblock_read_lock(struct dm_cache_metadata *cmd, 239 struct dm_block **sblock) 240 { 241 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 242 &sb_validator, sblock); 243 } 244 245 static int superblock_lock_zero(struct dm_cache_metadata *cmd, 246 struct dm_block **sblock) 247 { 248 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 249 &sb_validator, sblock); 250 } 251 252 static int superblock_lock(struct dm_cache_metadata *cmd, 253 struct dm_block **sblock) 254 { 255 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 256 &sb_validator, sblock); 257 } 258 259 /*----------------------------------------------------------------*/ 260 261 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result) 262 { 263 int r; 264 unsigned i; 265 struct dm_block *b; 266 __le64 *data_le, zero = cpu_to_le64(0); 267 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 268 269 /* 270 * We can't use a validator here - it may be all zeroes. 271 */ 272 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); 273 if (r) 274 return r; 275 276 data_le = dm_block_data(b); 277 *result = true; 278 for (i = 0; i < sb_block_size; i++) { 279 if (data_le[i] != zero) { 280 *result = false; 281 break; 282 } 283 } 284 285 dm_bm_unlock(b); 286 287 return 0; 288 } 289 290 static void __setup_mapping_info(struct dm_cache_metadata *cmd) 291 { 292 struct dm_btree_value_type vt; 293 294 vt.context = NULL; 295 vt.size = sizeof(__le64); 296 vt.inc = NULL; 297 vt.dec = NULL; 298 vt.equal = NULL; 299 dm_array_info_init(&cmd->info, cmd->tm, &vt); 300 301 if (cmd->policy_hint_size) { 302 vt.size = sizeof(__le32); 303 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); 304 } 305 } 306 307 static int __save_sm_root(struct dm_cache_metadata *cmd) 308 { 309 int r; 310 size_t metadata_len; 311 312 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 313 if (r < 0) 314 return r; 315 316 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root, 317 metadata_len); 318 } 319 320 static void __copy_sm_root(struct dm_cache_metadata *cmd, 321 struct cache_disk_superblock *disk_super) 322 { 323 memcpy(&disk_super->metadata_space_map_root, 324 &cmd->metadata_space_map_root, 325 sizeof(cmd->metadata_space_map_root)); 326 } 327 328 static bool separate_dirty_bits(struct dm_cache_metadata *cmd) 329 { 330 return cmd->version >= 2; 331 } 332 333 static int __write_initial_superblock(struct dm_cache_metadata *cmd) 334 { 335 int r; 336 struct dm_block *sblock; 337 struct cache_disk_superblock *disk_super; 338 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT; 339 340 /* FIXME: see if we can lose the max sectors limit */ 341 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) 342 bdev_size = DM_CACHE_METADATA_MAX_SECTORS; 343 344 r = dm_tm_pre_commit(cmd->tm); 345 if (r < 0) 346 return r; 347 348 /* 349 * dm_sm_copy_root() can fail. So we need to do it before we start 350 * updating the superblock. 351 */ 352 r = __save_sm_root(cmd); 353 if (r) 354 return r; 355 356 r = superblock_lock_zero(cmd, &sblock); 357 if (r) 358 return r; 359 360 disk_super = dm_block_data(sblock); 361 disk_super->flags = 0; 362 memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); 363 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); 364 disk_super->version = cpu_to_le32(cmd->version); 365 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); 366 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); 367 disk_super->policy_hint_size = 0; 368 369 __copy_sm_root(cmd, disk_super); 370 371 disk_super->mapping_root = cpu_to_le64(cmd->root); 372 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 373 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 374 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 375 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 376 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE); 377 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); 378 disk_super->cache_blocks = cpu_to_le32(0); 379 380 disk_super->read_hits = cpu_to_le32(0); 381 disk_super->read_misses = cpu_to_le32(0); 382 disk_super->write_hits = cpu_to_le32(0); 383 disk_super->write_misses = cpu_to_le32(0); 384 385 if (separate_dirty_bits(cmd)) 386 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); 387 388 return dm_tm_commit(cmd->tm, sblock); 389 } 390 391 static int __format_metadata(struct dm_cache_metadata *cmd) 392 { 393 int r; 394 395 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 396 &cmd->tm, &cmd->metadata_sm); 397 if (r < 0) { 398 DMERR("tm_create_with_sm failed"); 399 return r; 400 } 401 402 __setup_mapping_info(cmd); 403 404 r = dm_array_empty(&cmd->info, &cmd->root); 405 if (r < 0) 406 goto bad; 407 408 if (separate_dirty_bits(cmd)) { 409 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info); 410 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root); 411 if (r < 0) 412 goto bad; 413 } 414 415 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 416 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); 417 if (r < 0) 418 goto bad; 419 420 cmd->discard_block_size = 0; 421 cmd->discard_nr_blocks = 0; 422 423 r = __write_initial_superblock(cmd); 424 if (r) 425 goto bad; 426 427 cmd->clean_when_opened = true; 428 return 0; 429 430 bad: 431 dm_tm_destroy(cmd->tm); 432 dm_sm_destroy(cmd->metadata_sm); 433 434 return r; 435 } 436 437 static int __check_incompat_features(struct cache_disk_superblock *disk_super, 438 struct dm_cache_metadata *cmd) 439 { 440 uint32_t incompat_flags, features; 441 442 incompat_flags = le32_to_cpu(disk_super->incompat_flags); 443 features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; 444 if (features) { 445 DMERR("could not access metadata due to unsupported optional features (%lx).", 446 (unsigned long)features); 447 return -EINVAL; 448 } 449 450 /* 451 * Check for read-only metadata to skip the following RDWR checks. 452 */ 453 if (get_disk_ro(cmd->bdev->bd_disk)) 454 return 0; 455 456 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; 457 if (features) { 458 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", 459 (unsigned long)features); 460 return -EINVAL; 461 } 462 463 return 0; 464 } 465 466 static int __open_metadata(struct dm_cache_metadata *cmd) 467 { 468 int r; 469 struct dm_block *sblock; 470 struct cache_disk_superblock *disk_super; 471 unsigned long sb_flags; 472 473 r = superblock_read_lock(cmd, &sblock); 474 if (r < 0) { 475 DMERR("couldn't read lock superblock"); 476 return r; 477 } 478 479 disk_super = dm_block_data(sblock); 480 481 /* Verify the data block size hasn't changed */ 482 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) { 483 DMERR("changing the data block size (from %u to %llu) is not supported", 484 le32_to_cpu(disk_super->data_block_size), 485 (unsigned long long)cmd->data_block_size); 486 r = -EINVAL; 487 goto bad; 488 } 489 490 r = __check_incompat_features(disk_super, cmd); 491 if (r < 0) 492 goto bad; 493 494 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 495 disk_super->metadata_space_map_root, 496 sizeof(disk_super->metadata_space_map_root), 497 &cmd->tm, &cmd->metadata_sm); 498 if (r < 0) { 499 DMERR("tm_open_with_sm failed"); 500 goto bad; 501 } 502 503 __setup_mapping_info(cmd); 504 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info); 505 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 506 sb_flags = le32_to_cpu(disk_super->flags); 507 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); 508 dm_bm_unlock(sblock); 509 510 return 0; 511 512 bad: 513 dm_bm_unlock(sblock); 514 return r; 515 } 516 517 static int __open_or_format_metadata(struct dm_cache_metadata *cmd, 518 bool format_device) 519 { 520 int r; 521 bool unformatted = false; 522 523 r = __superblock_all_zeroes(cmd->bm, &unformatted); 524 if (r) 525 return r; 526 527 if (unformatted) 528 return format_device ? __format_metadata(cmd) : -EPERM; 529 530 return __open_metadata(cmd); 531 } 532 533 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, 534 bool may_format_device) 535 { 536 int r; 537 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, 538 CACHE_METADATA_CACHE_SIZE, 539 CACHE_MAX_CONCURRENT_LOCKS); 540 if (IS_ERR(cmd->bm)) { 541 DMERR("could not create block manager"); 542 return PTR_ERR(cmd->bm); 543 } 544 545 r = __open_or_format_metadata(cmd, may_format_device); 546 if (r) 547 dm_block_manager_destroy(cmd->bm); 548 549 return r; 550 } 551 552 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) 553 { 554 dm_sm_destroy(cmd->metadata_sm); 555 dm_tm_destroy(cmd->tm); 556 dm_block_manager_destroy(cmd->bm); 557 } 558 559 typedef unsigned long (*flags_mutator)(unsigned long); 560 561 static void update_flags(struct cache_disk_superblock *disk_super, 562 flags_mutator mutator) 563 { 564 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); 565 disk_super->flags = cpu_to_le32(sb_flags); 566 } 567 568 static unsigned long set_clean_shutdown(unsigned long flags) 569 { 570 set_bit(CLEAN_SHUTDOWN, &flags); 571 return flags; 572 } 573 574 static unsigned long clear_clean_shutdown(unsigned long flags) 575 { 576 clear_bit(CLEAN_SHUTDOWN, &flags); 577 return flags; 578 } 579 580 static void read_superblock_fields(struct dm_cache_metadata *cmd, 581 struct cache_disk_superblock *disk_super) 582 { 583 cmd->version = le32_to_cpu(disk_super->version); 584 cmd->flags = le32_to_cpu(disk_super->flags); 585 cmd->root = le64_to_cpu(disk_super->mapping_root); 586 cmd->hint_root = le64_to_cpu(disk_super->hint_root); 587 cmd->discard_root = le64_to_cpu(disk_super->discard_root); 588 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); 589 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); 590 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); 591 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); 592 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); 593 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); 594 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); 595 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); 596 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); 597 598 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); 599 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); 600 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); 601 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); 602 603 if (separate_dirty_bits(cmd)) 604 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root); 605 606 cmd->changed = false; 607 } 608 609 /* 610 * The mutator updates the superblock flags. 611 */ 612 static int __begin_transaction_flags(struct dm_cache_metadata *cmd, 613 flags_mutator mutator) 614 { 615 int r; 616 struct cache_disk_superblock *disk_super; 617 struct dm_block *sblock; 618 619 r = superblock_lock(cmd, &sblock); 620 if (r) 621 return r; 622 623 disk_super = dm_block_data(sblock); 624 update_flags(disk_super, mutator); 625 read_superblock_fields(cmd, disk_super); 626 dm_bm_unlock(sblock); 627 628 return dm_bm_flush(cmd->bm); 629 } 630 631 static int __begin_transaction(struct dm_cache_metadata *cmd) 632 { 633 int r; 634 struct cache_disk_superblock *disk_super; 635 struct dm_block *sblock; 636 637 /* 638 * We re-read the superblock every time. Shouldn't need to do this 639 * really. 640 */ 641 r = superblock_read_lock(cmd, &sblock); 642 if (r) 643 return r; 644 645 disk_super = dm_block_data(sblock); 646 read_superblock_fields(cmd, disk_super); 647 dm_bm_unlock(sblock); 648 649 return 0; 650 } 651 652 static int __commit_transaction(struct dm_cache_metadata *cmd, 653 flags_mutator mutator) 654 { 655 int r; 656 struct cache_disk_superblock *disk_super; 657 struct dm_block *sblock; 658 659 /* 660 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 661 */ 662 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 663 664 if (separate_dirty_bits(cmd)) { 665 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root, 666 &cmd->dirty_root); 667 if (r) 668 return r; 669 } 670 671 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 672 &cmd->discard_root); 673 if (r) 674 return r; 675 676 r = dm_tm_pre_commit(cmd->tm); 677 if (r < 0) 678 return r; 679 680 r = __save_sm_root(cmd); 681 if (r) 682 return r; 683 684 r = superblock_lock(cmd, &sblock); 685 if (r) 686 return r; 687 688 disk_super = dm_block_data(sblock); 689 690 disk_super->flags = cpu_to_le32(cmd->flags); 691 if (mutator) 692 update_flags(disk_super, mutator); 693 694 disk_super->mapping_root = cpu_to_le64(cmd->root); 695 if (separate_dirty_bits(cmd)) 696 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); 697 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 698 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 699 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 700 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 701 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 702 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 703 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); 704 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); 705 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); 706 707 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 708 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 709 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 710 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 711 __copy_sm_root(cmd, disk_super); 712 713 return dm_tm_commit(cmd->tm, sblock); 714 } 715 716 /*----------------------------------------------------------------*/ 717 718 /* 719 * The mappings are held in a dm-array that has 64-bit values stored in 720 * little-endian format. The index is the cblock, the high 48bits of the 721 * value are the oblock and the low 16 bit the flags. 722 */ 723 #define FLAGS_MASK ((1 << 16) - 1) 724 725 static __le64 pack_value(dm_oblock_t block, unsigned flags) 726 { 727 uint64_t value = from_oblock(block); 728 value <<= 16; 729 value = value | (flags & FLAGS_MASK); 730 return cpu_to_le64(value); 731 } 732 733 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 734 { 735 uint64_t value = le64_to_cpu(value_le); 736 uint64_t b = value >> 16; 737 *block = to_oblock(b); 738 *flags = value & FLAGS_MASK; 739 } 740 741 /*----------------------------------------------------------------*/ 742 743 static struct dm_cache_metadata *metadata_open(struct block_device *bdev, 744 sector_t data_block_size, 745 bool may_format_device, 746 size_t policy_hint_size, 747 unsigned metadata_version) 748 { 749 int r; 750 struct dm_cache_metadata *cmd; 751 752 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 753 if (!cmd) { 754 DMERR("could not allocate metadata struct"); 755 return ERR_PTR(-ENOMEM); 756 } 757 758 cmd->version = metadata_version; 759 atomic_set(&cmd->ref_count, 1); 760 init_rwsem(&cmd->root_lock); 761 cmd->bdev = bdev; 762 cmd->data_block_size = data_block_size; 763 cmd->cache_blocks = 0; 764 cmd->policy_hint_size = policy_hint_size; 765 cmd->changed = true; 766 cmd->fail_io = false; 767 768 r = __create_persistent_data_objects(cmd, may_format_device); 769 if (r) { 770 kfree(cmd); 771 return ERR_PTR(r); 772 } 773 774 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 775 if (r < 0) { 776 dm_cache_metadata_close(cmd); 777 return ERR_PTR(r); 778 } 779 780 return cmd; 781 } 782 783 /* 784 * We keep a little list of ref counted metadata objects to prevent two 785 * different target instances creating separate bufio instances. This is 786 * an issue if a table is reloaded before the suspend. 787 */ 788 static DEFINE_MUTEX(table_lock); 789 static LIST_HEAD(table); 790 791 static struct dm_cache_metadata *lookup(struct block_device *bdev) 792 { 793 struct dm_cache_metadata *cmd; 794 795 list_for_each_entry(cmd, &table, list) 796 if (cmd->bdev == bdev) { 797 atomic_inc(&cmd->ref_count); 798 return cmd; 799 } 800 801 return NULL; 802 } 803 804 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev, 805 sector_t data_block_size, 806 bool may_format_device, 807 size_t policy_hint_size, 808 unsigned metadata_version) 809 { 810 struct dm_cache_metadata *cmd, *cmd2; 811 812 mutex_lock(&table_lock); 813 cmd = lookup(bdev); 814 mutex_unlock(&table_lock); 815 816 if (cmd) 817 return cmd; 818 819 cmd = metadata_open(bdev, data_block_size, may_format_device, 820 policy_hint_size, metadata_version); 821 if (!IS_ERR(cmd)) { 822 mutex_lock(&table_lock); 823 cmd2 = lookup(bdev); 824 if (cmd2) { 825 mutex_unlock(&table_lock); 826 __destroy_persistent_data_objects(cmd); 827 kfree(cmd); 828 return cmd2; 829 } 830 list_add(&cmd->list, &table); 831 mutex_unlock(&table_lock); 832 } 833 834 return cmd; 835 } 836 837 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size) 838 { 839 if (cmd->data_block_size != data_block_size) { 840 DMERR("data_block_size (%llu) different from that in metadata (%llu)", 841 (unsigned long long) data_block_size, 842 (unsigned long long) cmd->data_block_size); 843 return false; 844 } 845 846 return true; 847 } 848 849 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 850 sector_t data_block_size, 851 bool may_format_device, 852 size_t policy_hint_size, 853 unsigned metadata_version) 854 { 855 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device, 856 policy_hint_size, metadata_version); 857 858 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) { 859 dm_cache_metadata_close(cmd); 860 return ERR_PTR(-EINVAL); 861 } 862 863 return cmd; 864 } 865 866 void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 867 { 868 if (atomic_dec_and_test(&cmd->ref_count)) { 869 mutex_lock(&table_lock); 870 list_del(&cmd->list); 871 mutex_unlock(&table_lock); 872 873 if (!cmd->fail_io) 874 __destroy_persistent_data_objects(cmd); 875 kfree(cmd); 876 } 877 } 878 879 /* 880 * Checks that the given cache block is either unmapped or clean. 881 */ 882 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b, 883 bool *result) 884 { 885 int r; 886 __le64 value; 887 dm_oblock_t ob; 888 unsigned flags; 889 890 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value); 891 if (r) 892 return r; 893 894 unpack_value(value, &ob, &flags); 895 *result = !((flags & M_VALID) && (flags & M_DIRTY)); 896 897 return 0; 898 } 899 900 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd, 901 dm_cblock_t begin, dm_cblock_t end, 902 bool *result) 903 { 904 int r; 905 *result = true; 906 907 while (begin != end) { 908 r = block_clean_combined_dirty(cmd, begin, result); 909 if (r) { 910 DMERR("block_clean_combined_dirty failed"); 911 return r; 912 } 913 914 if (!*result) { 915 DMERR("cache block %llu is dirty", 916 (unsigned long long) from_cblock(begin)); 917 return 0; 918 } 919 920 begin = to_cblock(from_cblock(begin) + 1); 921 } 922 923 return 0; 924 } 925 926 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd, 927 dm_cblock_t begin, dm_cblock_t end, 928 bool *result) 929 { 930 int r; 931 bool dirty_flag; 932 *result = true; 933 934 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, 935 from_cblock(begin), &cmd->dirty_cursor); 936 if (r) { 937 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__); 938 return r; 939 } 940 941 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin)); 942 if (r) { 943 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__); 944 dm_bitset_cursor_end(&cmd->dirty_cursor); 945 return r; 946 } 947 948 while (begin != end) { 949 /* 950 * We assume that unmapped blocks have their dirty bit 951 * cleared. 952 */ 953 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor); 954 if (dirty_flag) { 955 DMERR("%s: cache block %llu is dirty", __func__, 956 (unsigned long long) from_cblock(begin)); 957 dm_bitset_cursor_end(&cmd->dirty_cursor); 958 *result = false; 959 return 0; 960 } 961 962 r = dm_bitset_cursor_next(&cmd->dirty_cursor); 963 if (r) { 964 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__); 965 dm_bitset_cursor_end(&cmd->dirty_cursor); 966 return r; 967 } 968 969 begin = to_cblock(from_cblock(begin) + 1); 970 } 971 972 dm_bitset_cursor_end(&cmd->dirty_cursor); 973 974 return 0; 975 } 976 977 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd, 978 dm_cblock_t begin, dm_cblock_t end, 979 bool *result) 980 { 981 if (separate_dirty_bits(cmd)) 982 return blocks_are_clean_separate_dirty(cmd, begin, end, result); 983 else 984 return blocks_are_clean_combined_dirty(cmd, begin, end, result); 985 } 986 987 static bool cmd_write_lock(struct dm_cache_metadata *cmd) 988 { 989 down_write(&cmd->root_lock); 990 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { 991 up_write(&cmd->root_lock); 992 return false; 993 } 994 return true; 995 } 996 997 #define WRITE_LOCK(cmd) \ 998 do { \ 999 if (!cmd_write_lock((cmd))) \ 1000 return -EINVAL; \ 1001 } while(0) 1002 1003 #define WRITE_LOCK_VOID(cmd) \ 1004 do { \ 1005 if (!cmd_write_lock((cmd))) \ 1006 return; \ 1007 } while(0) 1008 1009 #define WRITE_UNLOCK(cmd) \ 1010 up_write(&(cmd)->root_lock) 1011 1012 static bool cmd_read_lock(struct dm_cache_metadata *cmd) 1013 { 1014 down_read(&cmd->root_lock); 1015 if (cmd->fail_io) { 1016 up_read(&cmd->root_lock); 1017 return false; 1018 } 1019 return true; 1020 } 1021 1022 #define READ_LOCK(cmd) \ 1023 do { \ 1024 if (!cmd_read_lock((cmd))) \ 1025 return -EINVAL; \ 1026 } while(0) 1027 1028 #define READ_LOCK_VOID(cmd) \ 1029 do { \ 1030 if (!cmd_read_lock((cmd))) \ 1031 return; \ 1032 } while(0) 1033 1034 #define READ_UNLOCK(cmd) \ 1035 up_read(&(cmd)->root_lock) 1036 1037 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) 1038 { 1039 int r; 1040 bool clean; 1041 __le64 null_mapping = pack_value(0, 0); 1042 1043 WRITE_LOCK(cmd); 1044 __dm_bless_for_disk(&null_mapping); 1045 1046 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) { 1047 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean); 1048 if (r) { 1049 __dm_unbless_for_disk(&null_mapping); 1050 goto out; 1051 } 1052 1053 if (!clean) { 1054 DMERR("unable to shrink cache due to dirty blocks"); 1055 r = -EINVAL; 1056 __dm_unbless_for_disk(&null_mapping); 1057 goto out; 1058 } 1059 } 1060 1061 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), 1062 from_cblock(new_cache_size), 1063 &null_mapping, &cmd->root); 1064 if (r) 1065 goto out; 1066 1067 if (separate_dirty_bits(cmd)) { 1068 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root, 1069 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size), 1070 false, &cmd->dirty_root); 1071 if (r) 1072 goto out; 1073 } 1074 1075 cmd->cache_blocks = new_cache_size; 1076 cmd->changed = true; 1077 1078 out: 1079 WRITE_UNLOCK(cmd); 1080 1081 return r; 1082 } 1083 1084 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 1085 sector_t discard_block_size, 1086 dm_dblock_t new_nr_entries) 1087 { 1088 int r; 1089 1090 WRITE_LOCK(cmd); 1091 r = dm_bitset_resize(&cmd->discard_info, 1092 cmd->discard_root, 1093 from_dblock(cmd->discard_nr_blocks), 1094 from_dblock(new_nr_entries), 1095 false, &cmd->discard_root); 1096 if (!r) { 1097 cmd->discard_block_size = discard_block_size; 1098 cmd->discard_nr_blocks = new_nr_entries; 1099 } 1100 1101 cmd->changed = true; 1102 WRITE_UNLOCK(cmd); 1103 1104 return r; 1105 } 1106 1107 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 1108 { 1109 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, 1110 from_dblock(b), &cmd->discard_root); 1111 } 1112 1113 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 1114 { 1115 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, 1116 from_dblock(b), &cmd->discard_root); 1117 } 1118 1119 static int __discard(struct dm_cache_metadata *cmd, 1120 dm_dblock_t dblock, bool discard) 1121 { 1122 int r; 1123 1124 r = (discard ? __set_discard : __clear_discard)(cmd, dblock); 1125 if (r) 1126 return r; 1127 1128 cmd->changed = true; 1129 return 0; 1130 } 1131 1132 int dm_cache_set_discard(struct dm_cache_metadata *cmd, 1133 dm_dblock_t dblock, bool discard) 1134 { 1135 int r; 1136 1137 WRITE_LOCK(cmd); 1138 r = __discard(cmd, dblock, discard); 1139 WRITE_UNLOCK(cmd); 1140 1141 return r; 1142 } 1143 1144 static int __load_discards(struct dm_cache_metadata *cmd, 1145 load_discard_fn fn, void *context) 1146 { 1147 int r = 0; 1148 uint32_t b; 1149 struct dm_bitset_cursor c; 1150 1151 if (from_dblock(cmd->discard_nr_blocks) == 0) 1152 /* nothing to do */ 1153 return 0; 1154 1155 if (cmd->clean_when_opened) { 1156 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root); 1157 if (r) 1158 return r; 1159 1160 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root, 1161 from_dblock(cmd->discard_nr_blocks), &c); 1162 if (r) 1163 return r; 1164 1165 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { 1166 r = fn(context, cmd->discard_block_size, to_dblock(b), 1167 dm_bitset_cursor_get_value(&c)); 1168 if (r) 1169 break; 1170 } 1171 1172 dm_bitset_cursor_end(&c); 1173 1174 } else { 1175 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { 1176 r = fn(context, cmd->discard_block_size, to_dblock(b), false); 1177 if (r) 1178 return r; 1179 } 1180 } 1181 1182 return r; 1183 } 1184 1185 int dm_cache_load_discards(struct dm_cache_metadata *cmd, 1186 load_discard_fn fn, void *context) 1187 { 1188 int r; 1189 1190 READ_LOCK(cmd); 1191 r = __load_discards(cmd, fn, context); 1192 READ_UNLOCK(cmd); 1193 1194 return r; 1195 } 1196 1197 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result) 1198 { 1199 READ_LOCK(cmd); 1200 *result = cmd->cache_blocks; 1201 READ_UNLOCK(cmd); 1202 1203 return 0; 1204 } 1205 1206 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 1207 { 1208 int r; 1209 __le64 value = pack_value(0, 0); 1210 1211 __dm_bless_for_disk(&value); 1212 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1213 &value, &cmd->root); 1214 if (r) 1215 return r; 1216 1217 cmd->changed = true; 1218 return 0; 1219 } 1220 1221 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 1222 { 1223 int r; 1224 1225 WRITE_LOCK(cmd); 1226 r = __remove(cmd, cblock); 1227 WRITE_UNLOCK(cmd); 1228 1229 return r; 1230 } 1231 1232 static int __insert(struct dm_cache_metadata *cmd, 1233 dm_cblock_t cblock, dm_oblock_t oblock) 1234 { 1235 int r; 1236 __le64 value = pack_value(oblock, M_VALID); 1237 __dm_bless_for_disk(&value); 1238 1239 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1240 &value, &cmd->root); 1241 if (r) 1242 return r; 1243 1244 cmd->changed = true; 1245 return 0; 1246 } 1247 1248 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, 1249 dm_cblock_t cblock, dm_oblock_t oblock) 1250 { 1251 int r; 1252 1253 WRITE_LOCK(cmd); 1254 r = __insert(cmd, cblock, oblock); 1255 WRITE_UNLOCK(cmd); 1256 1257 return r; 1258 } 1259 1260 struct thunk { 1261 load_mapping_fn fn; 1262 void *context; 1263 1264 struct dm_cache_metadata *cmd; 1265 bool respect_dirty_flags; 1266 bool hints_valid; 1267 }; 1268 1269 static bool policy_unchanged(struct dm_cache_metadata *cmd, 1270 struct dm_cache_policy *policy) 1271 { 1272 const char *policy_name = dm_cache_policy_get_name(policy); 1273 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1274 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); 1275 1276 /* 1277 * Ensure policy names match. 1278 */ 1279 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) 1280 return false; 1281 1282 /* 1283 * Ensure policy major versions match. 1284 */ 1285 if (cmd->policy_version[0] != policy_version[0]) 1286 return false; 1287 1288 /* 1289 * Ensure policy hint sizes match. 1290 */ 1291 if (cmd->policy_hint_size != policy_hint_size) 1292 return false; 1293 1294 return true; 1295 } 1296 1297 static bool hints_array_initialized(struct dm_cache_metadata *cmd) 1298 { 1299 return cmd->hint_root && cmd->policy_hint_size; 1300 } 1301 1302 static bool hints_array_available(struct dm_cache_metadata *cmd, 1303 struct dm_cache_policy *policy) 1304 { 1305 return cmd->clean_when_opened && policy_unchanged(cmd, policy) && 1306 hints_array_initialized(cmd); 1307 } 1308 1309 static int __load_mapping_v1(struct dm_cache_metadata *cmd, 1310 uint64_t cb, bool hints_valid, 1311 struct dm_array_cursor *mapping_cursor, 1312 struct dm_array_cursor *hint_cursor, 1313 load_mapping_fn fn, void *context) 1314 { 1315 int r = 0; 1316 1317 __le64 mapping; 1318 __le32 hint = 0; 1319 1320 __le64 *mapping_value_le; 1321 __le32 *hint_value_le; 1322 1323 dm_oblock_t oblock; 1324 unsigned flags; 1325 1326 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le); 1327 memcpy(&mapping, mapping_value_le, sizeof(mapping)); 1328 unpack_value(mapping, &oblock, &flags); 1329 1330 if (flags & M_VALID) { 1331 if (hints_valid) { 1332 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le); 1333 memcpy(&hint, hint_value_le, sizeof(hint)); 1334 } 1335 1336 r = fn(context, oblock, to_cblock(cb), flags & M_DIRTY, 1337 le32_to_cpu(hint), hints_valid); 1338 if (r) { 1339 DMERR("policy couldn't load cache block %llu", 1340 (unsigned long long) from_cblock(to_cblock(cb))); 1341 } 1342 } 1343 1344 return r; 1345 } 1346 1347 static int __load_mapping_v2(struct dm_cache_metadata *cmd, 1348 uint64_t cb, bool hints_valid, 1349 struct dm_array_cursor *mapping_cursor, 1350 struct dm_array_cursor *hint_cursor, 1351 struct dm_bitset_cursor *dirty_cursor, 1352 load_mapping_fn fn, void *context) 1353 { 1354 int r = 0; 1355 1356 __le64 mapping; 1357 __le32 hint = 0; 1358 1359 __le64 *mapping_value_le; 1360 __le32 *hint_value_le; 1361 1362 dm_oblock_t oblock; 1363 unsigned flags; 1364 bool dirty; 1365 1366 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le); 1367 memcpy(&mapping, mapping_value_le, sizeof(mapping)); 1368 unpack_value(mapping, &oblock, &flags); 1369 1370 if (flags & M_VALID) { 1371 if (hints_valid) { 1372 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le); 1373 memcpy(&hint, hint_value_le, sizeof(hint)); 1374 } 1375 1376 dirty = dm_bitset_cursor_get_value(dirty_cursor); 1377 r = fn(context, oblock, to_cblock(cb), dirty, 1378 le32_to_cpu(hint), hints_valid); 1379 if (r) { 1380 DMERR("policy couldn't load cache block %llu", 1381 (unsigned long long) from_cblock(to_cblock(cb))); 1382 } 1383 } 1384 1385 return r; 1386 } 1387 1388 static int __load_mappings(struct dm_cache_metadata *cmd, 1389 struct dm_cache_policy *policy, 1390 load_mapping_fn fn, void *context) 1391 { 1392 int r; 1393 uint64_t cb; 1394 1395 bool hints_valid = hints_array_available(cmd, policy); 1396 1397 if (from_cblock(cmd->cache_blocks) == 0) 1398 /* Nothing to do */ 1399 return 0; 1400 1401 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor); 1402 if (r) 1403 return r; 1404 1405 if (hints_valid) { 1406 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor); 1407 if (r) { 1408 dm_array_cursor_end(&cmd->mapping_cursor); 1409 return r; 1410 } 1411 } 1412 1413 if (separate_dirty_bits(cmd)) { 1414 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, 1415 from_cblock(cmd->cache_blocks), 1416 &cmd->dirty_cursor); 1417 if (r) { 1418 dm_array_cursor_end(&cmd->hint_cursor); 1419 dm_array_cursor_end(&cmd->mapping_cursor); 1420 return r; 1421 } 1422 } 1423 1424 for (cb = 0; ; cb++) { 1425 if (separate_dirty_bits(cmd)) 1426 r = __load_mapping_v2(cmd, cb, hints_valid, 1427 &cmd->mapping_cursor, 1428 &cmd->hint_cursor, 1429 &cmd->dirty_cursor, 1430 fn, context); 1431 else 1432 r = __load_mapping_v1(cmd, cb, hints_valid, 1433 &cmd->mapping_cursor, &cmd->hint_cursor, 1434 fn, context); 1435 if (r) 1436 goto out; 1437 1438 /* 1439 * We need to break out before we move the cursors. 1440 */ 1441 if (cb >= (from_cblock(cmd->cache_blocks) - 1)) 1442 break; 1443 1444 r = dm_array_cursor_next(&cmd->mapping_cursor); 1445 if (r) { 1446 DMERR("dm_array_cursor_next for mapping failed"); 1447 goto out; 1448 } 1449 1450 if (hints_valid) { 1451 r = dm_array_cursor_next(&cmd->hint_cursor); 1452 if (r) { 1453 DMERR("dm_array_cursor_next for hint failed"); 1454 goto out; 1455 } 1456 } 1457 1458 if (separate_dirty_bits(cmd)) { 1459 r = dm_bitset_cursor_next(&cmd->dirty_cursor); 1460 if (r) { 1461 DMERR("dm_bitset_cursor_next for dirty failed"); 1462 goto out; 1463 } 1464 } 1465 } 1466 out: 1467 dm_array_cursor_end(&cmd->mapping_cursor); 1468 if (hints_valid) 1469 dm_array_cursor_end(&cmd->hint_cursor); 1470 1471 if (separate_dirty_bits(cmd)) 1472 dm_bitset_cursor_end(&cmd->dirty_cursor); 1473 1474 return r; 1475 } 1476 1477 int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 1478 struct dm_cache_policy *policy, 1479 load_mapping_fn fn, void *context) 1480 { 1481 int r; 1482 1483 READ_LOCK(cmd); 1484 r = __load_mappings(cmd, policy, fn, context); 1485 READ_UNLOCK(cmd); 1486 1487 return r; 1488 } 1489 1490 static int __dump_mapping(void *context, uint64_t cblock, void *leaf) 1491 { 1492 int r = 0; 1493 __le64 value; 1494 dm_oblock_t oblock; 1495 unsigned flags; 1496 1497 memcpy(&value, leaf, sizeof(value)); 1498 unpack_value(value, &oblock, &flags); 1499 1500 return r; 1501 } 1502 1503 static int __dump_mappings(struct dm_cache_metadata *cmd) 1504 { 1505 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); 1506 } 1507 1508 void dm_cache_dump(struct dm_cache_metadata *cmd) 1509 { 1510 READ_LOCK_VOID(cmd); 1511 __dump_mappings(cmd); 1512 READ_UNLOCK(cmd); 1513 } 1514 1515 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) 1516 { 1517 int r; 1518 1519 READ_LOCK(cmd); 1520 r = cmd->changed; 1521 READ_UNLOCK(cmd); 1522 1523 return r; 1524 } 1525 1526 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) 1527 { 1528 int r; 1529 unsigned flags; 1530 dm_oblock_t oblock; 1531 __le64 value; 1532 1533 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); 1534 if (r) 1535 return r; 1536 1537 unpack_value(value, &oblock, &flags); 1538 1539 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) 1540 /* nothing to be done */ 1541 return 0; 1542 1543 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); 1544 __dm_bless_for_disk(&value); 1545 1546 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1547 &value, &cmd->root); 1548 if (r) 1549 return r; 1550 1551 cmd->changed = true; 1552 return 0; 1553 1554 } 1555 1556 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits) 1557 { 1558 int r; 1559 unsigned i; 1560 for (i = 0; i < nr_bits; i++) { 1561 r = __dirty(cmd, to_cblock(i), test_bit(i, bits)); 1562 if (r) 1563 return r; 1564 } 1565 1566 return 0; 1567 } 1568 1569 static int is_dirty_callback(uint32_t index, bool *value, void *context) 1570 { 1571 unsigned long *bits = context; 1572 *value = test_bit(index, bits); 1573 return 0; 1574 } 1575 1576 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits) 1577 { 1578 int r = 0; 1579 1580 /* nr_bits is really just a sanity check */ 1581 if (nr_bits != from_cblock(cmd->cache_blocks)) { 1582 DMERR("dirty bitset is wrong size"); 1583 return -EINVAL; 1584 } 1585 1586 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root); 1587 if (r) 1588 return r; 1589 1590 cmd->changed = true; 1591 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits); 1592 } 1593 1594 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd, 1595 unsigned nr_bits, 1596 unsigned long *bits) 1597 { 1598 int r; 1599 1600 WRITE_LOCK(cmd); 1601 if (separate_dirty_bits(cmd)) 1602 r = __set_dirty_bits_v2(cmd, nr_bits, bits); 1603 else 1604 r = __set_dirty_bits_v1(cmd, nr_bits, bits); 1605 WRITE_UNLOCK(cmd); 1606 1607 return r; 1608 } 1609 1610 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 1611 struct dm_cache_statistics *stats) 1612 { 1613 READ_LOCK_VOID(cmd); 1614 *stats = cmd->stats; 1615 READ_UNLOCK(cmd); 1616 } 1617 1618 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 1619 struct dm_cache_statistics *stats) 1620 { 1621 WRITE_LOCK_VOID(cmd); 1622 cmd->stats = *stats; 1623 WRITE_UNLOCK(cmd); 1624 } 1625 1626 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) 1627 { 1628 int r; 1629 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1630 clear_clean_shutdown); 1631 1632 WRITE_LOCK(cmd); 1633 r = __commit_transaction(cmd, mutator); 1634 if (r) 1635 goto out; 1636 1637 r = __begin_transaction(cmd); 1638 1639 out: 1640 WRITE_UNLOCK(cmd); 1641 return r; 1642 } 1643 1644 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1645 dm_block_t *result) 1646 { 1647 int r = -EINVAL; 1648 1649 READ_LOCK(cmd); 1650 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1651 READ_UNLOCK(cmd); 1652 1653 return r; 1654 } 1655 1656 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1657 dm_block_t *result) 1658 { 1659 int r = -EINVAL; 1660 1661 READ_LOCK(cmd); 1662 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1663 READ_UNLOCK(cmd); 1664 1665 return r; 1666 } 1667 1668 /*----------------------------------------------------------------*/ 1669 1670 static int get_hint(uint32_t index, void *value_le, void *context) 1671 { 1672 uint32_t value; 1673 struct dm_cache_policy *policy = context; 1674 1675 value = policy_get_hint(policy, to_cblock(index)); 1676 *((__le32 *) value_le) = cpu_to_le32(value); 1677 1678 return 0; 1679 } 1680 1681 /* 1682 * It's quicker to always delete the hint array, and recreate with 1683 * dm_array_new(). 1684 */ 1685 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1686 { 1687 int r; 1688 size_t hint_size; 1689 const char *policy_name = dm_cache_policy_get_name(policy); 1690 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1691 1692 if (!policy_name[0] || 1693 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1694 return -EINVAL; 1695 1696 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1697 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); 1698 1699 hint_size = dm_cache_policy_get_hint_size(policy); 1700 if (!hint_size) 1701 return 0; /* short-circuit hints initialization */ 1702 cmd->policy_hint_size = hint_size; 1703 1704 if (cmd->hint_root) { 1705 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1706 if (r) 1707 return r; 1708 } 1709 1710 return dm_array_new(&cmd->hint_info, &cmd->hint_root, 1711 from_cblock(cmd->cache_blocks), 1712 get_hint, policy); 1713 } 1714 1715 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1716 { 1717 int r; 1718 1719 WRITE_LOCK(cmd); 1720 r = write_hints(cmd, policy); 1721 WRITE_UNLOCK(cmd); 1722 1723 return r; 1724 } 1725 1726 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result) 1727 { 1728 int r; 1729 1730 READ_LOCK(cmd); 1731 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result); 1732 READ_UNLOCK(cmd); 1733 1734 return r; 1735 } 1736 1737 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd) 1738 { 1739 WRITE_LOCK_VOID(cmd); 1740 dm_bm_set_read_only(cmd->bm); 1741 WRITE_UNLOCK(cmd); 1742 } 1743 1744 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd) 1745 { 1746 WRITE_LOCK_VOID(cmd); 1747 dm_bm_set_read_write(cmd->bm); 1748 WRITE_UNLOCK(cmd); 1749 } 1750 1751 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd) 1752 { 1753 int r; 1754 struct dm_block *sblock; 1755 struct cache_disk_superblock *disk_super; 1756 1757 WRITE_LOCK(cmd); 1758 set_bit(NEEDS_CHECK, &cmd->flags); 1759 1760 r = superblock_lock(cmd, &sblock); 1761 if (r) { 1762 DMERR("couldn't read superblock"); 1763 goto out; 1764 } 1765 1766 disk_super = dm_block_data(sblock); 1767 disk_super->flags = cpu_to_le32(cmd->flags); 1768 1769 dm_bm_unlock(sblock); 1770 1771 out: 1772 WRITE_UNLOCK(cmd); 1773 return r; 1774 } 1775 1776 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result) 1777 { 1778 READ_LOCK(cmd); 1779 *result = !!test_bit(NEEDS_CHECK, &cmd->flags); 1780 READ_UNLOCK(cmd); 1781 1782 return 0; 1783 } 1784 1785 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd) 1786 { 1787 int r; 1788 1789 WRITE_LOCK(cmd); 1790 __destroy_persistent_data_objects(cmd); 1791 r = __create_persistent_data_objects(cmd, false); 1792 if (r) 1793 cmd->fail_io = true; 1794 WRITE_UNLOCK(cmd); 1795 1796 return r; 1797 } 1798