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 #include <linux/refcount.h> 17 18 /*----------------------------------------------------------------*/ 19 20 #define DM_MSG_PREFIX "cache metadata" 21 22 #define CACHE_SUPERBLOCK_MAGIC 06142003 23 #define CACHE_SUPERBLOCK_LOCATION 0 24 25 /* 26 * defines a range of metadata versions that this module can handle. 27 */ 28 #define MIN_CACHE_VERSION 1 29 #define MAX_CACHE_VERSION 2 30 31 /* 32 * 3 for btree insert + 33 * 2 for btree lookup used within space map 34 */ 35 #define CACHE_MAX_CONCURRENT_LOCKS 5 36 #define SPACE_MAP_ROOT_SIZE 128 37 38 enum superblock_flag_bits { 39 /* for spotting crashes that would invalidate the dirty bitset */ 40 CLEAN_SHUTDOWN, 41 /* metadata must be checked using the tools */ 42 NEEDS_CHECK, 43 }; 44 45 /* 46 * Each mapping from cache block -> origin block carries a set of flags. 47 */ 48 enum mapping_bits { 49 /* 50 * A valid mapping. Because we're using an array we clear this 51 * flag for an non existant mapping. 52 */ 53 M_VALID = 1, 54 55 /* 56 * The data on the cache is different from that on the origin. 57 * This flag is only used by metadata format 1. 58 */ 59 M_DIRTY = 2 60 }; 61 62 struct cache_disk_superblock { 63 __le32 csum; 64 __le32 flags; 65 __le64 blocknr; 66 67 __u8 uuid[16]; 68 __le64 magic; 69 __le32 version; 70 71 __u8 policy_name[CACHE_POLICY_NAME_SIZE]; 72 __le32 policy_hint_size; 73 74 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 75 __le64 mapping_root; 76 __le64 hint_root; 77 78 __le64 discard_root; 79 __le64 discard_block_size; 80 __le64 discard_nr_blocks; 81 82 __le32 data_block_size; 83 __le32 metadata_block_size; 84 __le32 cache_blocks; 85 86 __le32 compat_flags; 87 __le32 compat_ro_flags; 88 __le32 incompat_flags; 89 90 __le32 read_hits; 91 __le32 read_misses; 92 __le32 write_hits; 93 __le32 write_misses; 94 95 __le32 policy_version[CACHE_POLICY_VERSION_SIZE]; 96 97 /* 98 * Metadata format 2 fields. 99 */ 100 __le64 dirty_root; 101 } __packed; 102 103 struct dm_cache_metadata { 104 refcount_t ref_count; 105 struct list_head list; 106 107 unsigned version; 108 struct block_device *bdev; 109 struct dm_block_manager *bm; 110 struct dm_space_map *metadata_sm; 111 struct dm_transaction_manager *tm; 112 113 struct dm_array_info info; 114 struct dm_array_info hint_info; 115 struct dm_disk_bitset discard_info; 116 117 struct rw_semaphore root_lock; 118 unsigned long flags; 119 dm_block_t root; 120 dm_block_t hint_root; 121 dm_block_t discard_root; 122 123 sector_t discard_block_size; 124 dm_dblock_t discard_nr_blocks; 125 126 sector_t data_block_size; 127 dm_cblock_t cache_blocks; 128 bool changed:1; 129 bool clean_when_opened:1; 130 131 char policy_name[CACHE_POLICY_NAME_SIZE]; 132 unsigned policy_version[CACHE_POLICY_VERSION_SIZE]; 133 size_t policy_hint_size; 134 struct dm_cache_statistics stats; 135 136 /* 137 * Reading the space map root can fail, so we read it into this 138 * buffer before the superblock is locked and updated. 139 */ 140 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 141 142 /* 143 * Set if a transaction has to be aborted but the attempt to roll 144 * back to the previous (good) transaction failed. The only 145 * metadata operation permissible in this state is the closing of 146 * the device. 147 */ 148 bool fail_io:1; 149 150 /* 151 * Metadata format 2 fields. 152 */ 153 dm_block_t dirty_root; 154 struct dm_disk_bitset dirty_info; 155 156 /* 157 * These structures are used when loading metadata. They're too 158 * big to put on the stack. 159 */ 160 struct dm_array_cursor mapping_cursor; 161 struct dm_array_cursor hint_cursor; 162 struct dm_bitset_cursor dirty_cursor; 163 }; 164 165 /*------------------------------------------------------------------- 166 * superblock validator 167 *-----------------------------------------------------------------*/ 168 169 #define SUPERBLOCK_CSUM_XOR 9031977 170 171 static void sb_prepare_for_write(struct dm_block_validator *v, 172 struct dm_block *b, 173 size_t sb_block_size) 174 { 175 struct cache_disk_superblock *disk_super = dm_block_data(b); 176 177 disk_super->blocknr = cpu_to_le64(dm_block_location(b)); 178 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 179 sb_block_size - sizeof(__le32), 180 SUPERBLOCK_CSUM_XOR)); 181 } 182 183 static int check_metadata_version(struct cache_disk_superblock *disk_super) 184 { 185 uint32_t metadata_version = le32_to_cpu(disk_super->version); 186 187 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) { 188 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.", 189 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION); 190 return -EINVAL; 191 } 192 193 return 0; 194 } 195 196 static int sb_check(struct dm_block_validator *v, 197 struct dm_block *b, 198 size_t sb_block_size) 199 { 200 struct cache_disk_superblock *disk_super = dm_block_data(b); 201 __le32 csum_le; 202 203 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { 204 DMERR("sb_check failed: blocknr %llu: wanted %llu", 205 le64_to_cpu(disk_super->blocknr), 206 (unsigned long long)dm_block_location(b)); 207 return -ENOTBLK; 208 } 209 210 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { 211 DMERR("sb_check failed: magic %llu: wanted %llu", 212 le64_to_cpu(disk_super->magic), 213 (unsigned long long)CACHE_SUPERBLOCK_MAGIC); 214 return -EILSEQ; 215 } 216 217 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 218 sb_block_size - sizeof(__le32), 219 SUPERBLOCK_CSUM_XOR)); 220 if (csum_le != disk_super->csum) { 221 DMERR("sb_check failed: csum %u: wanted %u", 222 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); 223 return -EILSEQ; 224 } 225 226 return check_metadata_version(disk_super); 227 } 228 229 static struct dm_block_validator sb_validator = { 230 .name = "superblock", 231 .prepare_for_write = sb_prepare_for_write, 232 .check = sb_check 233 }; 234 235 /*----------------------------------------------------------------*/ 236 237 static int superblock_read_lock(struct dm_cache_metadata *cmd, 238 struct dm_block **sblock) 239 { 240 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 241 &sb_validator, sblock); 242 } 243 244 static int superblock_lock_zero(struct dm_cache_metadata *cmd, 245 struct dm_block **sblock) 246 { 247 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 248 &sb_validator, sblock); 249 } 250 251 static int superblock_lock(struct dm_cache_metadata *cmd, 252 struct dm_block **sblock) 253 { 254 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 255 &sb_validator, sblock); 256 } 257 258 /*----------------------------------------------------------------*/ 259 260 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result) 261 { 262 int r; 263 unsigned i; 264 struct dm_block *b; 265 __le64 *data_le, zero = cpu_to_le64(0); 266 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 267 268 /* 269 * We can't use a validator here - it may be all zeroes. 270 */ 271 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); 272 if (r) 273 return r; 274 275 data_le = dm_block_data(b); 276 *result = true; 277 for (i = 0; i < sb_block_size; i++) { 278 if (data_le[i] != zero) { 279 *result = false; 280 break; 281 } 282 } 283 284 dm_bm_unlock(b); 285 286 return 0; 287 } 288 289 static void __setup_mapping_info(struct dm_cache_metadata *cmd) 290 { 291 struct dm_btree_value_type vt; 292 293 vt.context = NULL; 294 vt.size = sizeof(__le64); 295 vt.inc = NULL; 296 vt.dec = NULL; 297 vt.equal = NULL; 298 dm_array_info_init(&cmd->info, cmd->tm, &vt); 299 300 if (cmd->policy_hint_size) { 301 vt.size = sizeof(__le32); 302 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); 303 } 304 } 305 306 static int __save_sm_root(struct dm_cache_metadata *cmd) 307 { 308 int r; 309 size_t metadata_len; 310 311 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 312 if (r < 0) 313 return r; 314 315 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root, 316 metadata_len); 317 } 318 319 static void __copy_sm_root(struct dm_cache_metadata *cmd, 320 struct cache_disk_superblock *disk_super) 321 { 322 memcpy(&disk_super->metadata_space_map_root, 323 &cmd->metadata_space_map_root, 324 sizeof(cmd->metadata_space_map_root)); 325 } 326 327 static bool separate_dirty_bits(struct dm_cache_metadata *cmd) 328 { 329 return cmd->version >= 2; 330 } 331 332 static int __write_initial_superblock(struct dm_cache_metadata *cmd) 333 { 334 int r; 335 struct dm_block *sblock; 336 struct cache_disk_superblock *disk_super; 337 sector_t bdev_size = bdev_nr_sectors(cmd->bdev); 338 339 /* FIXME: see if we can lose the max sectors limit */ 340 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) 341 bdev_size = DM_CACHE_METADATA_MAX_SECTORS; 342 343 r = dm_tm_pre_commit(cmd->tm); 344 if (r < 0) 345 return r; 346 347 /* 348 * dm_sm_copy_root() can fail. So we need to do it before we start 349 * updating the superblock. 350 */ 351 r = __save_sm_root(cmd); 352 if (r) 353 return r; 354 355 r = superblock_lock_zero(cmd, &sblock); 356 if (r) 357 return r; 358 359 disk_super = dm_block_data(sblock); 360 disk_super->flags = 0; 361 memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); 362 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); 363 disk_super->version = cpu_to_le32(cmd->version); 364 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); 365 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); 366 disk_super->policy_hint_size = cpu_to_le32(0); 367 368 __copy_sm_root(cmd, disk_super); 369 370 disk_super->mapping_root = cpu_to_le64(cmd->root); 371 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 372 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 373 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 374 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 375 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE); 376 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); 377 disk_super->cache_blocks = cpu_to_le32(0); 378 379 disk_super->read_hits = cpu_to_le32(0); 380 disk_super->read_misses = cpu_to_le32(0); 381 disk_super->write_hits = cpu_to_le32(0); 382 disk_super->write_misses = cpu_to_le32(0); 383 384 if (separate_dirty_bits(cmd)) 385 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); 386 387 return dm_tm_commit(cmd->tm, sblock); 388 } 389 390 static int __format_metadata(struct dm_cache_metadata *cmd) 391 { 392 int r; 393 394 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 395 &cmd->tm, &cmd->metadata_sm); 396 if (r < 0) { 397 DMERR("tm_create_with_sm failed"); 398 return r; 399 } 400 401 __setup_mapping_info(cmd); 402 403 r = dm_array_empty(&cmd->info, &cmd->root); 404 if (r < 0) 405 goto bad; 406 407 if (separate_dirty_bits(cmd)) { 408 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info); 409 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root); 410 if (r < 0) 411 goto bad; 412 } 413 414 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 415 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); 416 if (r < 0) 417 goto bad; 418 419 cmd->discard_block_size = 0; 420 cmd->discard_nr_blocks = 0; 421 422 r = __write_initial_superblock(cmd); 423 if (r) 424 goto bad; 425 426 cmd->clean_when_opened = true; 427 return 0; 428 429 bad: 430 dm_tm_destroy(cmd->tm); 431 dm_sm_destroy(cmd->metadata_sm); 432 433 return r; 434 } 435 436 static int __check_incompat_features(struct cache_disk_superblock *disk_super, 437 struct dm_cache_metadata *cmd) 438 { 439 uint32_t incompat_flags, features; 440 441 incompat_flags = le32_to_cpu(disk_super->incompat_flags); 442 features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; 443 if (features) { 444 DMERR("could not access metadata due to unsupported optional features (%lx).", 445 (unsigned long)features); 446 return -EINVAL; 447 } 448 449 /* 450 * Check for read-only metadata to skip the following RDWR checks. 451 */ 452 if (bdev_read_only(cmd->bdev)) 453 return 0; 454 455 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; 456 if (features) { 457 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", 458 (unsigned long)features); 459 return -EINVAL; 460 } 461 462 return 0; 463 } 464 465 static int __open_metadata(struct dm_cache_metadata *cmd) 466 { 467 int r; 468 struct dm_block *sblock; 469 struct cache_disk_superblock *disk_super; 470 unsigned long sb_flags; 471 472 r = superblock_read_lock(cmd, &sblock); 473 if (r < 0) { 474 DMERR("couldn't read lock superblock"); 475 return r; 476 } 477 478 disk_super = dm_block_data(sblock); 479 480 /* Verify the data block size hasn't changed */ 481 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) { 482 DMERR("changing the data block size (from %u to %llu) is not supported", 483 le32_to_cpu(disk_super->data_block_size), 484 (unsigned long long)cmd->data_block_size); 485 r = -EINVAL; 486 goto bad; 487 } 488 489 r = __check_incompat_features(disk_super, cmd); 490 if (r < 0) 491 goto bad; 492 493 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 494 disk_super->metadata_space_map_root, 495 sizeof(disk_super->metadata_space_map_root), 496 &cmd->tm, &cmd->metadata_sm); 497 if (r < 0) { 498 DMERR("tm_open_with_sm failed"); 499 goto bad; 500 } 501 502 __setup_mapping_info(cmd); 503 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info); 504 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 505 sb_flags = le32_to_cpu(disk_super->flags); 506 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); 507 dm_bm_unlock(sblock); 508 509 return 0; 510 511 bad: 512 dm_bm_unlock(sblock); 513 return r; 514 } 515 516 static int __open_or_format_metadata(struct dm_cache_metadata *cmd, 517 bool format_device) 518 { 519 int r; 520 bool unformatted = false; 521 522 r = __superblock_all_zeroes(cmd->bm, &unformatted); 523 if (r) 524 return r; 525 526 if (unformatted) 527 return format_device ? __format_metadata(cmd) : -EPERM; 528 529 return __open_metadata(cmd); 530 } 531 532 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, 533 bool may_format_device) 534 { 535 int r; 536 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, 537 CACHE_MAX_CONCURRENT_LOCKS); 538 if (IS_ERR(cmd->bm)) { 539 DMERR("could not create block manager"); 540 r = PTR_ERR(cmd->bm); 541 cmd->bm = NULL; 542 return r; 543 } 544 545 r = __open_or_format_metadata(cmd, may_format_device); 546 if (r) { 547 dm_block_manager_destroy(cmd->bm); 548 cmd->bm = NULL; 549 } 550 551 return r; 552 } 553 554 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd, 555 bool destroy_bm) 556 { 557 dm_sm_destroy(cmd->metadata_sm); 558 dm_tm_destroy(cmd->tm); 559 if (destroy_bm) 560 dm_block_manager_destroy(cmd->bm); 561 } 562 563 typedef unsigned long (*flags_mutator)(unsigned long); 564 565 static void update_flags(struct cache_disk_superblock *disk_super, 566 flags_mutator mutator) 567 { 568 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); 569 disk_super->flags = cpu_to_le32(sb_flags); 570 } 571 572 static unsigned long set_clean_shutdown(unsigned long flags) 573 { 574 set_bit(CLEAN_SHUTDOWN, &flags); 575 return flags; 576 } 577 578 static unsigned long clear_clean_shutdown(unsigned long flags) 579 { 580 clear_bit(CLEAN_SHUTDOWN, &flags); 581 return flags; 582 } 583 584 static void read_superblock_fields(struct dm_cache_metadata *cmd, 585 struct cache_disk_superblock *disk_super) 586 { 587 cmd->version = le32_to_cpu(disk_super->version); 588 cmd->flags = le32_to_cpu(disk_super->flags); 589 cmd->root = le64_to_cpu(disk_super->mapping_root); 590 cmd->hint_root = le64_to_cpu(disk_super->hint_root); 591 cmd->discard_root = le64_to_cpu(disk_super->discard_root); 592 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); 593 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); 594 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); 595 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); 596 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); 597 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); 598 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); 599 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); 600 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); 601 602 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); 603 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); 604 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); 605 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); 606 607 if (separate_dirty_bits(cmd)) 608 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root); 609 610 cmd->changed = false; 611 } 612 613 /* 614 * The mutator updates the superblock flags. 615 */ 616 static int __begin_transaction_flags(struct dm_cache_metadata *cmd, 617 flags_mutator mutator) 618 { 619 int r; 620 struct cache_disk_superblock *disk_super; 621 struct dm_block *sblock; 622 623 r = superblock_lock(cmd, &sblock); 624 if (r) 625 return r; 626 627 disk_super = dm_block_data(sblock); 628 update_flags(disk_super, mutator); 629 read_superblock_fields(cmd, disk_super); 630 dm_bm_unlock(sblock); 631 632 return dm_bm_flush(cmd->bm); 633 } 634 635 static int __begin_transaction(struct dm_cache_metadata *cmd) 636 { 637 int r; 638 struct cache_disk_superblock *disk_super; 639 struct dm_block *sblock; 640 641 /* 642 * We re-read the superblock every time. Shouldn't need to do this 643 * really. 644 */ 645 r = superblock_read_lock(cmd, &sblock); 646 if (r) 647 return r; 648 649 disk_super = dm_block_data(sblock); 650 read_superblock_fields(cmd, disk_super); 651 dm_bm_unlock(sblock); 652 653 return 0; 654 } 655 656 static int __commit_transaction(struct dm_cache_metadata *cmd, 657 flags_mutator mutator) 658 { 659 int r; 660 struct cache_disk_superblock *disk_super; 661 struct dm_block *sblock; 662 663 /* 664 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 665 */ 666 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 667 668 if (separate_dirty_bits(cmd)) { 669 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root, 670 &cmd->dirty_root); 671 if (r) 672 return r; 673 } 674 675 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 676 &cmd->discard_root); 677 if (r) 678 return r; 679 680 r = dm_tm_pre_commit(cmd->tm); 681 if (r < 0) 682 return r; 683 684 r = __save_sm_root(cmd); 685 if (r) 686 return r; 687 688 r = superblock_lock(cmd, &sblock); 689 if (r) 690 return r; 691 692 disk_super = dm_block_data(sblock); 693 694 disk_super->flags = cpu_to_le32(cmd->flags); 695 if (mutator) 696 update_flags(disk_super, mutator); 697 698 disk_super->mapping_root = cpu_to_le64(cmd->root); 699 if (separate_dirty_bits(cmd)) 700 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); 701 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 702 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 703 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 704 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 705 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 706 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 707 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); 708 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); 709 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); 710 disk_super->policy_hint_size = cpu_to_le32(cmd->policy_hint_size); 711 712 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 713 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 714 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 715 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 716 __copy_sm_root(cmd, disk_super); 717 718 return dm_tm_commit(cmd->tm, sblock); 719 } 720 721 /*----------------------------------------------------------------*/ 722 723 /* 724 * The mappings are held in a dm-array that has 64-bit values stored in 725 * little-endian format. The index is the cblock, the high 48bits of the 726 * value are the oblock and the low 16 bit the flags. 727 */ 728 #define FLAGS_MASK ((1 << 16) - 1) 729 730 static __le64 pack_value(dm_oblock_t block, unsigned flags) 731 { 732 uint64_t value = from_oblock(block); 733 value <<= 16; 734 value = value | (flags & FLAGS_MASK); 735 return cpu_to_le64(value); 736 } 737 738 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 739 { 740 uint64_t value = le64_to_cpu(value_le); 741 uint64_t b = value >> 16; 742 *block = to_oblock(b); 743 *flags = value & FLAGS_MASK; 744 } 745 746 /*----------------------------------------------------------------*/ 747 748 static struct dm_cache_metadata *metadata_open(struct block_device *bdev, 749 sector_t data_block_size, 750 bool may_format_device, 751 size_t policy_hint_size, 752 unsigned metadata_version) 753 { 754 int r; 755 struct dm_cache_metadata *cmd; 756 757 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 758 if (!cmd) { 759 DMERR("could not allocate metadata struct"); 760 return ERR_PTR(-ENOMEM); 761 } 762 763 cmd->version = metadata_version; 764 refcount_set(&cmd->ref_count, 1); 765 init_rwsem(&cmd->root_lock); 766 cmd->bdev = bdev; 767 cmd->data_block_size = data_block_size; 768 cmd->cache_blocks = 0; 769 cmd->policy_hint_size = policy_hint_size; 770 cmd->changed = true; 771 cmd->fail_io = false; 772 773 r = __create_persistent_data_objects(cmd, may_format_device); 774 if (r) { 775 kfree(cmd); 776 return ERR_PTR(r); 777 } 778 779 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 780 if (r < 0) { 781 dm_cache_metadata_close(cmd); 782 return ERR_PTR(r); 783 } 784 785 return cmd; 786 } 787 788 /* 789 * We keep a little list of ref counted metadata objects to prevent two 790 * different target instances creating separate bufio instances. This is 791 * an issue if a table is reloaded before the suspend. 792 */ 793 static DEFINE_MUTEX(table_lock); 794 static LIST_HEAD(table); 795 796 static struct dm_cache_metadata *lookup(struct block_device *bdev) 797 { 798 struct dm_cache_metadata *cmd; 799 800 list_for_each_entry(cmd, &table, list) 801 if (cmd->bdev == bdev) { 802 refcount_inc(&cmd->ref_count); 803 return cmd; 804 } 805 806 return NULL; 807 } 808 809 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev, 810 sector_t data_block_size, 811 bool may_format_device, 812 size_t policy_hint_size, 813 unsigned metadata_version) 814 { 815 struct dm_cache_metadata *cmd, *cmd2; 816 817 mutex_lock(&table_lock); 818 cmd = lookup(bdev); 819 mutex_unlock(&table_lock); 820 821 if (cmd) 822 return cmd; 823 824 cmd = metadata_open(bdev, data_block_size, may_format_device, 825 policy_hint_size, metadata_version); 826 if (!IS_ERR(cmd)) { 827 mutex_lock(&table_lock); 828 cmd2 = lookup(bdev); 829 if (cmd2) { 830 mutex_unlock(&table_lock); 831 __destroy_persistent_data_objects(cmd, true); 832 kfree(cmd); 833 return cmd2; 834 } 835 list_add(&cmd->list, &table); 836 mutex_unlock(&table_lock); 837 } 838 839 return cmd; 840 } 841 842 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size) 843 { 844 if (cmd->data_block_size != data_block_size) { 845 DMERR("data_block_size (%llu) different from that in metadata (%llu)", 846 (unsigned long long) data_block_size, 847 (unsigned long long) cmd->data_block_size); 848 return false; 849 } 850 851 return true; 852 } 853 854 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 855 sector_t data_block_size, 856 bool may_format_device, 857 size_t policy_hint_size, 858 unsigned metadata_version) 859 { 860 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device, 861 policy_hint_size, metadata_version); 862 863 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) { 864 dm_cache_metadata_close(cmd); 865 return ERR_PTR(-EINVAL); 866 } 867 868 return cmd; 869 } 870 871 void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 872 { 873 if (refcount_dec_and_test(&cmd->ref_count)) { 874 mutex_lock(&table_lock); 875 list_del(&cmd->list); 876 mutex_unlock(&table_lock); 877 878 if (!cmd->fail_io) 879 __destroy_persistent_data_objects(cmd, true); 880 kfree(cmd); 881 } 882 } 883 884 /* 885 * Checks that the given cache block is either unmapped or clean. 886 */ 887 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b, 888 bool *result) 889 { 890 int r; 891 __le64 value; 892 dm_oblock_t ob; 893 unsigned flags; 894 895 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value); 896 if (r) 897 return r; 898 899 unpack_value(value, &ob, &flags); 900 *result = !((flags & M_VALID) && (flags & M_DIRTY)); 901 902 return 0; 903 } 904 905 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd, 906 dm_cblock_t begin, dm_cblock_t end, 907 bool *result) 908 { 909 int r; 910 *result = true; 911 912 while (begin != end) { 913 r = block_clean_combined_dirty(cmd, begin, result); 914 if (r) { 915 DMERR("block_clean_combined_dirty failed"); 916 return r; 917 } 918 919 if (!*result) { 920 DMERR("cache block %llu is dirty", 921 (unsigned long long) from_cblock(begin)); 922 return 0; 923 } 924 925 begin = to_cblock(from_cblock(begin) + 1); 926 } 927 928 return 0; 929 } 930 931 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd, 932 dm_cblock_t begin, dm_cblock_t end, 933 bool *result) 934 { 935 int r; 936 bool dirty_flag; 937 *result = true; 938 939 if (from_cblock(cmd->cache_blocks) == 0) 940 /* Nothing to do */ 941 return 0; 942 943 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, 944 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor); 945 if (r) { 946 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__); 947 return r; 948 } 949 950 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin)); 951 if (r) { 952 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__); 953 dm_bitset_cursor_end(&cmd->dirty_cursor); 954 return r; 955 } 956 957 while (begin != end) { 958 /* 959 * We assume that unmapped blocks have their dirty bit 960 * cleared. 961 */ 962 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor); 963 if (dirty_flag) { 964 DMERR("%s: cache block %llu is dirty", __func__, 965 (unsigned long long) from_cblock(begin)); 966 dm_bitset_cursor_end(&cmd->dirty_cursor); 967 *result = false; 968 return 0; 969 } 970 971 begin = to_cblock(from_cblock(begin) + 1); 972 if (begin == end) 973 break; 974 975 r = dm_bitset_cursor_next(&cmd->dirty_cursor); 976 if (r) { 977 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__); 978 dm_bitset_cursor_end(&cmd->dirty_cursor); 979 return r; 980 } 981 } 982 983 dm_bitset_cursor_end(&cmd->dirty_cursor); 984 985 return 0; 986 } 987 988 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd, 989 dm_cblock_t begin, dm_cblock_t end, 990 bool *result) 991 { 992 if (separate_dirty_bits(cmd)) 993 return blocks_are_clean_separate_dirty(cmd, begin, end, result); 994 else 995 return blocks_are_clean_combined_dirty(cmd, begin, end, result); 996 } 997 998 static bool cmd_write_lock(struct dm_cache_metadata *cmd) 999 { 1000 down_write(&cmd->root_lock); 1001 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { 1002 up_write(&cmd->root_lock); 1003 return false; 1004 } 1005 return true; 1006 } 1007 1008 #define WRITE_LOCK(cmd) \ 1009 do { \ 1010 if (!cmd_write_lock((cmd))) \ 1011 return -EINVAL; \ 1012 } while(0) 1013 1014 #define WRITE_LOCK_VOID(cmd) \ 1015 do { \ 1016 if (!cmd_write_lock((cmd))) \ 1017 return; \ 1018 } while(0) 1019 1020 #define WRITE_UNLOCK(cmd) \ 1021 up_write(&(cmd)->root_lock) 1022 1023 static bool cmd_read_lock(struct dm_cache_metadata *cmd) 1024 { 1025 down_read(&cmd->root_lock); 1026 if (cmd->fail_io) { 1027 up_read(&cmd->root_lock); 1028 return false; 1029 } 1030 return true; 1031 } 1032 1033 #define READ_LOCK(cmd) \ 1034 do { \ 1035 if (!cmd_read_lock((cmd))) \ 1036 return -EINVAL; \ 1037 } while(0) 1038 1039 #define READ_LOCK_VOID(cmd) \ 1040 do { \ 1041 if (!cmd_read_lock((cmd))) \ 1042 return; \ 1043 } while(0) 1044 1045 #define READ_UNLOCK(cmd) \ 1046 up_read(&(cmd)->root_lock) 1047 1048 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) 1049 { 1050 int r; 1051 bool clean; 1052 __le64 null_mapping = pack_value(0, 0); 1053 1054 WRITE_LOCK(cmd); 1055 __dm_bless_for_disk(&null_mapping); 1056 1057 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) { 1058 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean); 1059 if (r) { 1060 __dm_unbless_for_disk(&null_mapping); 1061 goto out; 1062 } 1063 1064 if (!clean) { 1065 DMERR("unable to shrink cache due to dirty blocks"); 1066 r = -EINVAL; 1067 __dm_unbless_for_disk(&null_mapping); 1068 goto out; 1069 } 1070 } 1071 1072 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), 1073 from_cblock(new_cache_size), 1074 &null_mapping, &cmd->root); 1075 if (r) 1076 goto out; 1077 1078 if (separate_dirty_bits(cmd)) { 1079 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root, 1080 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size), 1081 false, &cmd->dirty_root); 1082 if (r) 1083 goto out; 1084 } 1085 1086 cmd->cache_blocks = new_cache_size; 1087 cmd->changed = true; 1088 1089 out: 1090 WRITE_UNLOCK(cmd); 1091 1092 return r; 1093 } 1094 1095 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 1096 sector_t discard_block_size, 1097 dm_dblock_t new_nr_entries) 1098 { 1099 int r; 1100 1101 WRITE_LOCK(cmd); 1102 r = dm_bitset_resize(&cmd->discard_info, 1103 cmd->discard_root, 1104 from_dblock(cmd->discard_nr_blocks), 1105 from_dblock(new_nr_entries), 1106 false, &cmd->discard_root); 1107 if (!r) { 1108 cmd->discard_block_size = discard_block_size; 1109 cmd->discard_nr_blocks = new_nr_entries; 1110 } 1111 1112 cmd->changed = true; 1113 WRITE_UNLOCK(cmd); 1114 1115 return r; 1116 } 1117 1118 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 1119 { 1120 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, 1121 from_dblock(b), &cmd->discard_root); 1122 } 1123 1124 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 1125 { 1126 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, 1127 from_dblock(b), &cmd->discard_root); 1128 } 1129 1130 static int __discard(struct dm_cache_metadata *cmd, 1131 dm_dblock_t dblock, bool discard) 1132 { 1133 int r; 1134 1135 r = (discard ? __set_discard : __clear_discard)(cmd, dblock); 1136 if (r) 1137 return r; 1138 1139 cmd->changed = true; 1140 return 0; 1141 } 1142 1143 int dm_cache_set_discard(struct dm_cache_metadata *cmd, 1144 dm_dblock_t dblock, bool discard) 1145 { 1146 int r; 1147 1148 WRITE_LOCK(cmd); 1149 r = __discard(cmd, dblock, discard); 1150 WRITE_UNLOCK(cmd); 1151 1152 return r; 1153 } 1154 1155 static int __load_discards(struct dm_cache_metadata *cmd, 1156 load_discard_fn fn, void *context) 1157 { 1158 int r = 0; 1159 uint32_t b; 1160 struct dm_bitset_cursor c; 1161 1162 if (from_dblock(cmd->discard_nr_blocks) == 0) 1163 /* nothing to do */ 1164 return 0; 1165 1166 if (cmd->clean_when_opened) { 1167 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root); 1168 if (r) 1169 return r; 1170 1171 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root, 1172 from_dblock(cmd->discard_nr_blocks), &c); 1173 if (r) 1174 return r; 1175 1176 for (b = 0; ; b++) { 1177 r = fn(context, cmd->discard_block_size, to_dblock(b), 1178 dm_bitset_cursor_get_value(&c)); 1179 if (r) 1180 break; 1181 1182 if (b >= (from_dblock(cmd->discard_nr_blocks) - 1)) 1183 break; 1184 1185 r = dm_bitset_cursor_next(&c); 1186 if (r) 1187 break; 1188 } 1189 1190 dm_bitset_cursor_end(&c); 1191 1192 } else { 1193 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { 1194 r = fn(context, cmd->discard_block_size, to_dblock(b), false); 1195 if (r) 1196 return r; 1197 } 1198 } 1199 1200 return r; 1201 } 1202 1203 int dm_cache_load_discards(struct dm_cache_metadata *cmd, 1204 load_discard_fn fn, void *context) 1205 { 1206 int r; 1207 1208 READ_LOCK(cmd); 1209 r = __load_discards(cmd, fn, context); 1210 READ_UNLOCK(cmd); 1211 1212 return r; 1213 } 1214 1215 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result) 1216 { 1217 READ_LOCK(cmd); 1218 *result = cmd->cache_blocks; 1219 READ_UNLOCK(cmd); 1220 1221 return 0; 1222 } 1223 1224 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 1225 { 1226 int r; 1227 __le64 value = pack_value(0, 0); 1228 1229 __dm_bless_for_disk(&value); 1230 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1231 &value, &cmd->root); 1232 if (r) 1233 return r; 1234 1235 cmd->changed = true; 1236 return 0; 1237 } 1238 1239 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 1240 { 1241 int r; 1242 1243 WRITE_LOCK(cmd); 1244 r = __remove(cmd, cblock); 1245 WRITE_UNLOCK(cmd); 1246 1247 return r; 1248 } 1249 1250 static int __insert(struct dm_cache_metadata *cmd, 1251 dm_cblock_t cblock, dm_oblock_t oblock) 1252 { 1253 int r; 1254 __le64 value = pack_value(oblock, M_VALID); 1255 __dm_bless_for_disk(&value); 1256 1257 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1258 &value, &cmd->root); 1259 if (r) 1260 return r; 1261 1262 cmd->changed = true; 1263 return 0; 1264 } 1265 1266 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, 1267 dm_cblock_t cblock, dm_oblock_t oblock) 1268 { 1269 int r; 1270 1271 WRITE_LOCK(cmd); 1272 r = __insert(cmd, cblock, oblock); 1273 WRITE_UNLOCK(cmd); 1274 1275 return r; 1276 } 1277 1278 struct thunk { 1279 load_mapping_fn fn; 1280 void *context; 1281 1282 struct dm_cache_metadata *cmd; 1283 bool respect_dirty_flags; 1284 bool hints_valid; 1285 }; 1286 1287 static bool policy_unchanged(struct dm_cache_metadata *cmd, 1288 struct dm_cache_policy *policy) 1289 { 1290 const char *policy_name = dm_cache_policy_get_name(policy); 1291 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1292 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); 1293 1294 /* 1295 * Ensure policy names match. 1296 */ 1297 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) 1298 return false; 1299 1300 /* 1301 * Ensure policy major versions match. 1302 */ 1303 if (cmd->policy_version[0] != policy_version[0]) 1304 return false; 1305 1306 /* 1307 * Ensure policy hint sizes match. 1308 */ 1309 if (cmd->policy_hint_size != policy_hint_size) 1310 return false; 1311 1312 return true; 1313 } 1314 1315 static bool hints_array_initialized(struct dm_cache_metadata *cmd) 1316 { 1317 return cmd->hint_root && cmd->policy_hint_size; 1318 } 1319 1320 static bool hints_array_available(struct dm_cache_metadata *cmd, 1321 struct dm_cache_policy *policy) 1322 { 1323 return cmd->clean_when_opened && policy_unchanged(cmd, policy) && 1324 hints_array_initialized(cmd); 1325 } 1326 1327 static int __load_mapping_v1(struct dm_cache_metadata *cmd, 1328 uint64_t cb, bool hints_valid, 1329 struct dm_array_cursor *mapping_cursor, 1330 struct dm_array_cursor *hint_cursor, 1331 load_mapping_fn fn, void *context) 1332 { 1333 int r = 0; 1334 1335 __le64 mapping; 1336 __le32 hint = 0; 1337 1338 __le64 *mapping_value_le; 1339 __le32 *hint_value_le; 1340 1341 dm_oblock_t oblock; 1342 unsigned flags; 1343 bool dirty = true; 1344 1345 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le); 1346 memcpy(&mapping, mapping_value_le, sizeof(mapping)); 1347 unpack_value(mapping, &oblock, &flags); 1348 1349 if (flags & M_VALID) { 1350 if (hints_valid) { 1351 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le); 1352 memcpy(&hint, hint_value_le, sizeof(hint)); 1353 } 1354 if (cmd->clean_when_opened) 1355 dirty = flags & M_DIRTY; 1356 1357 r = fn(context, oblock, to_cblock(cb), dirty, 1358 le32_to_cpu(hint), hints_valid); 1359 if (r) { 1360 DMERR("policy couldn't load cache block %llu", 1361 (unsigned long long) from_cblock(to_cblock(cb))); 1362 } 1363 } 1364 1365 return r; 1366 } 1367 1368 static int __load_mapping_v2(struct dm_cache_metadata *cmd, 1369 uint64_t cb, bool hints_valid, 1370 struct dm_array_cursor *mapping_cursor, 1371 struct dm_array_cursor *hint_cursor, 1372 struct dm_bitset_cursor *dirty_cursor, 1373 load_mapping_fn fn, void *context) 1374 { 1375 int r = 0; 1376 1377 __le64 mapping; 1378 __le32 hint = 0; 1379 1380 __le64 *mapping_value_le; 1381 __le32 *hint_value_le; 1382 1383 dm_oblock_t oblock; 1384 unsigned flags; 1385 bool dirty = true; 1386 1387 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le); 1388 memcpy(&mapping, mapping_value_le, sizeof(mapping)); 1389 unpack_value(mapping, &oblock, &flags); 1390 1391 if (flags & M_VALID) { 1392 if (hints_valid) { 1393 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le); 1394 memcpy(&hint, hint_value_le, sizeof(hint)); 1395 } 1396 if (cmd->clean_when_opened) 1397 dirty = dm_bitset_cursor_get_value(dirty_cursor); 1398 1399 r = fn(context, oblock, to_cblock(cb), dirty, 1400 le32_to_cpu(hint), hints_valid); 1401 if (r) { 1402 DMERR("policy couldn't load cache block %llu", 1403 (unsigned long long) from_cblock(to_cblock(cb))); 1404 } 1405 } 1406 1407 return r; 1408 } 1409 1410 static int __load_mappings(struct dm_cache_metadata *cmd, 1411 struct dm_cache_policy *policy, 1412 load_mapping_fn fn, void *context) 1413 { 1414 int r; 1415 uint64_t cb; 1416 1417 bool hints_valid = hints_array_available(cmd, policy); 1418 1419 if (from_cblock(cmd->cache_blocks) == 0) 1420 /* Nothing to do */ 1421 return 0; 1422 1423 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor); 1424 if (r) 1425 return r; 1426 1427 if (hints_valid) { 1428 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor); 1429 if (r) { 1430 dm_array_cursor_end(&cmd->mapping_cursor); 1431 return r; 1432 } 1433 } 1434 1435 if (separate_dirty_bits(cmd)) { 1436 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, 1437 from_cblock(cmd->cache_blocks), 1438 &cmd->dirty_cursor); 1439 if (r) { 1440 dm_array_cursor_end(&cmd->hint_cursor); 1441 dm_array_cursor_end(&cmd->mapping_cursor); 1442 return r; 1443 } 1444 } 1445 1446 for (cb = 0; ; cb++) { 1447 if (separate_dirty_bits(cmd)) 1448 r = __load_mapping_v2(cmd, cb, hints_valid, 1449 &cmd->mapping_cursor, 1450 &cmd->hint_cursor, 1451 &cmd->dirty_cursor, 1452 fn, context); 1453 else 1454 r = __load_mapping_v1(cmd, cb, hints_valid, 1455 &cmd->mapping_cursor, &cmd->hint_cursor, 1456 fn, context); 1457 if (r) 1458 goto out; 1459 1460 /* 1461 * We need to break out before we move the cursors. 1462 */ 1463 if (cb >= (from_cblock(cmd->cache_blocks) - 1)) 1464 break; 1465 1466 r = dm_array_cursor_next(&cmd->mapping_cursor); 1467 if (r) { 1468 DMERR("dm_array_cursor_next for mapping failed"); 1469 goto out; 1470 } 1471 1472 if (hints_valid) { 1473 r = dm_array_cursor_next(&cmd->hint_cursor); 1474 if (r) { 1475 dm_array_cursor_end(&cmd->hint_cursor); 1476 hints_valid = false; 1477 } 1478 } 1479 1480 if (separate_dirty_bits(cmd)) { 1481 r = dm_bitset_cursor_next(&cmd->dirty_cursor); 1482 if (r) { 1483 DMERR("dm_bitset_cursor_next for dirty failed"); 1484 goto out; 1485 } 1486 } 1487 } 1488 out: 1489 dm_array_cursor_end(&cmd->mapping_cursor); 1490 if (hints_valid) 1491 dm_array_cursor_end(&cmd->hint_cursor); 1492 1493 if (separate_dirty_bits(cmd)) 1494 dm_bitset_cursor_end(&cmd->dirty_cursor); 1495 1496 return r; 1497 } 1498 1499 int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 1500 struct dm_cache_policy *policy, 1501 load_mapping_fn fn, void *context) 1502 { 1503 int r; 1504 1505 READ_LOCK(cmd); 1506 r = __load_mappings(cmd, policy, fn, context); 1507 READ_UNLOCK(cmd); 1508 1509 return r; 1510 } 1511 1512 static int __dump_mapping(void *context, uint64_t cblock, void *leaf) 1513 { 1514 __le64 value; 1515 dm_oblock_t oblock; 1516 unsigned flags; 1517 1518 memcpy(&value, leaf, sizeof(value)); 1519 unpack_value(value, &oblock, &flags); 1520 1521 return 0; 1522 } 1523 1524 static int __dump_mappings(struct dm_cache_metadata *cmd) 1525 { 1526 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); 1527 } 1528 1529 void dm_cache_dump(struct dm_cache_metadata *cmd) 1530 { 1531 READ_LOCK_VOID(cmd); 1532 __dump_mappings(cmd); 1533 READ_UNLOCK(cmd); 1534 } 1535 1536 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) 1537 { 1538 int r; 1539 1540 READ_LOCK(cmd); 1541 r = cmd->changed; 1542 READ_UNLOCK(cmd); 1543 1544 return r; 1545 } 1546 1547 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) 1548 { 1549 int r; 1550 unsigned flags; 1551 dm_oblock_t oblock; 1552 __le64 value; 1553 1554 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); 1555 if (r) 1556 return r; 1557 1558 unpack_value(value, &oblock, &flags); 1559 1560 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) 1561 /* nothing to be done */ 1562 return 0; 1563 1564 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); 1565 __dm_bless_for_disk(&value); 1566 1567 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1568 &value, &cmd->root); 1569 if (r) 1570 return r; 1571 1572 cmd->changed = true; 1573 return 0; 1574 1575 } 1576 1577 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits) 1578 { 1579 int r; 1580 unsigned i; 1581 for (i = 0; i < nr_bits; i++) { 1582 r = __dirty(cmd, to_cblock(i), test_bit(i, bits)); 1583 if (r) 1584 return r; 1585 } 1586 1587 return 0; 1588 } 1589 1590 static int is_dirty_callback(uint32_t index, bool *value, void *context) 1591 { 1592 unsigned long *bits = context; 1593 *value = test_bit(index, bits); 1594 return 0; 1595 } 1596 1597 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits) 1598 { 1599 int r = 0; 1600 1601 /* nr_bits is really just a sanity check */ 1602 if (nr_bits != from_cblock(cmd->cache_blocks)) { 1603 DMERR("dirty bitset is wrong size"); 1604 return -EINVAL; 1605 } 1606 1607 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root); 1608 if (r) 1609 return r; 1610 1611 cmd->changed = true; 1612 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits); 1613 } 1614 1615 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd, 1616 unsigned nr_bits, 1617 unsigned long *bits) 1618 { 1619 int r; 1620 1621 WRITE_LOCK(cmd); 1622 if (separate_dirty_bits(cmd)) 1623 r = __set_dirty_bits_v2(cmd, nr_bits, bits); 1624 else 1625 r = __set_dirty_bits_v1(cmd, nr_bits, bits); 1626 WRITE_UNLOCK(cmd); 1627 1628 return r; 1629 } 1630 1631 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 1632 struct dm_cache_statistics *stats) 1633 { 1634 READ_LOCK_VOID(cmd); 1635 *stats = cmd->stats; 1636 READ_UNLOCK(cmd); 1637 } 1638 1639 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 1640 struct dm_cache_statistics *stats) 1641 { 1642 WRITE_LOCK_VOID(cmd); 1643 cmd->stats = *stats; 1644 WRITE_UNLOCK(cmd); 1645 } 1646 1647 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) 1648 { 1649 int r = -EINVAL; 1650 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1651 clear_clean_shutdown); 1652 1653 WRITE_LOCK(cmd); 1654 if (cmd->fail_io) 1655 goto out; 1656 1657 r = __commit_transaction(cmd, mutator); 1658 if (r) 1659 goto out; 1660 1661 r = __begin_transaction(cmd); 1662 out: 1663 WRITE_UNLOCK(cmd); 1664 return r; 1665 } 1666 1667 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1668 dm_block_t *result) 1669 { 1670 int r = -EINVAL; 1671 1672 READ_LOCK(cmd); 1673 if (!cmd->fail_io) 1674 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1675 READ_UNLOCK(cmd); 1676 1677 return r; 1678 } 1679 1680 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1681 dm_block_t *result) 1682 { 1683 int r = -EINVAL; 1684 1685 READ_LOCK(cmd); 1686 if (!cmd->fail_io) 1687 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1688 READ_UNLOCK(cmd); 1689 1690 return r; 1691 } 1692 1693 /*----------------------------------------------------------------*/ 1694 1695 static int get_hint(uint32_t index, void *value_le, void *context) 1696 { 1697 uint32_t value; 1698 struct dm_cache_policy *policy = context; 1699 1700 value = policy_get_hint(policy, to_cblock(index)); 1701 *((__le32 *) value_le) = cpu_to_le32(value); 1702 1703 return 0; 1704 } 1705 1706 /* 1707 * It's quicker to always delete the hint array, and recreate with 1708 * dm_array_new(). 1709 */ 1710 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1711 { 1712 int r; 1713 size_t hint_size; 1714 const char *policy_name = dm_cache_policy_get_name(policy); 1715 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1716 1717 if (!policy_name[0] || 1718 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1719 return -EINVAL; 1720 1721 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1722 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); 1723 1724 hint_size = dm_cache_policy_get_hint_size(policy); 1725 if (!hint_size) 1726 return 0; /* short-circuit hints initialization */ 1727 cmd->policy_hint_size = hint_size; 1728 1729 if (cmd->hint_root) { 1730 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1731 if (r) 1732 return r; 1733 } 1734 1735 return dm_array_new(&cmd->hint_info, &cmd->hint_root, 1736 from_cblock(cmd->cache_blocks), 1737 get_hint, policy); 1738 } 1739 1740 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1741 { 1742 int r; 1743 1744 WRITE_LOCK(cmd); 1745 r = write_hints(cmd, policy); 1746 WRITE_UNLOCK(cmd); 1747 1748 return r; 1749 } 1750 1751 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result) 1752 { 1753 int r; 1754 1755 READ_LOCK(cmd); 1756 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result); 1757 READ_UNLOCK(cmd); 1758 1759 return r; 1760 } 1761 1762 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd) 1763 { 1764 WRITE_LOCK_VOID(cmd); 1765 dm_bm_set_read_only(cmd->bm); 1766 WRITE_UNLOCK(cmd); 1767 } 1768 1769 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd) 1770 { 1771 WRITE_LOCK_VOID(cmd); 1772 dm_bm_set_read_write(cmd->bm); 1773 WRITE_UNLOCK(cmd); 1774 } 1775 1776 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd) 1777 { 1778 int r; 1779 struct dm_block *sblock; 1780 struct cache_disk_superblock *disk_super; 1781 1782 WRITE_LOCK(cmd); 1783 set_bit(NEEDS_CHECK, &cmd->flags); 1784 1785 r = superblock_lock(cmd, &sblock); 1786 if (r) { 1787 DMERR("couldn't read superblock"); 1788 goto out; 1789 } 1790 1791 disk_super = dm_block_data(sblock); 1792 disk_super->flags = cpu_to_le32(cmd->flags); 1793 1794 dm_bm_unlock(sblock); 1795 1796 out: 1797 WRITE_UNLOCK(cmd); 1798 return r; 1799 } 1800 1801 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result) 1802 { 1803 READ_LOCK(cmd); 1804 *result = !!test_bit(NEEDS_CHECK, &cmd->flags); 1805 READ_UNLOCK(cmd); 1806 1807 return 0; 1808 } 1809 1810 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd) 1811 { 1812 int r = -EINVAL; 1813 struct dm_block_manager *old_bm = NULL, *new_bm = NULL; 1814 1815 /* fail_io is double-checked with cmd->root_lock held below */ 1816 if (unlikely(cmd->fail_io)) 1817 return r; 1818 1819 /* 1820 * Replacement block manager (new_bm) is created and old_bm destroyed outside of 1821 * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of 1822 * shrinker associated with the block manager's bufio client vs cmd root_lock). 1823 * - must take shrinker_rwsem without holding cmd->root_lock 1824 */ 1825 new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, 1826 CACHE_MAX_CONCURRENT_LOCKS); 1827 1828 WRITE_LOCK(cmd); 1829 if (cmd->fail_io) { 1830 WRITE_UNLOCK(cmd); 1831 goto out; 1832 } 1833 1834 __destroy_persistent_data_objects(cmd, false); 1835 old_bm = cmd->bm; 1836 if (IS_ERR(new_bm)) { 1837 DMERR("could not create block manager during abort"); 1838 cmd->bm = NULL; 1839 r = PTR_ERR(new_bm); 1840 goto out_unlock; 1841 } 1842 1843 cmd->bm = new_bm; 1844 r = __open_or_format_metadata(cmd, false); 1845 if (r) { 1846 cmd->bm = NULL; 1847 goto out_unlock; 1848 } 1849 new_bm = NULL; 1850 out_unlock: 1851 if (r) 1852 cmd->fail_io = true; 1853 WRITE_UNLOCK(cmd); 1854 dm_block_manager_destroy(old_bm); 1855 out: 1856 if (new_bm && !IS_ERR(new_bm)) 1857 dm_block_manager_destroy(new_bm); 1858 1859 return r; 1860 } 1861