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 = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT; 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 = 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 (get_disk_ro(cmd->bdev->bd_disk)) 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 return PTR_ERR(cmd->bm); 541 } 542 543 r = __open_or_format_metadata(cmd, may_format_device); 544 if (r) 545 dm_block_manager_destroy(cmd->bm); 546 547 return r; 548 } 549 550 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) 551 { 552 dm_sm_destroy(cmd->metadata_sm); 553 dm_tm_destroy(cmd->tm); 554 dm_block_manager_destroy(cmd->bm); 555 } 556 557 typedef unsigned long (*flags_mutator)(unsigned long); 558 559 static void update_flags(struct cache_disk_superblock *disk_super, 560 flags_mutator mutator) 561 { 562 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); 563 disk_super->flags = cpu_to_le32(sb_flags); 564 } 565 566 static unsigned long set_clean_shutdown(unsigned long flags) 567 { 568 set_bit(CLEAN_SHUTDOWN, &flags); 569 return flags; 570 } 571 572 static unsigned long clear_clean_shutdown(unsigned long flags) 573 { 574 clear_bit(CLEAN_SHUTDOWN, &flags); 575 return flags; 576 } 577 578 static void read_superblock_fields(struct dm_cache_metadata *cmd, 579 struct cache_disk_superblock *disk_super) 580 { 581 cmd->version = le32_to_cpu(disk_super->version); 582 cmd->flags = le32_to_cpu(disk_super->flags); 583 cmd->root = le64_to_cpu(disk_super->mapping_root); 584 cmd->hint_root = le64_to_cpu(disk_super->hint_root); 585 cmd->discard_root = le64_to_cpu(disk_super->discard_root); 586 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); 587 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); 588 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); 589 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); 590 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); 591 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); 592 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); 593 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); 594 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); 595 596 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); 597 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); 598 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); 599 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); 600 601 if (separate_dirty_bits(cmd)) 602 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root); 603 604 cmd->changed = false; 605 } 606 607 /* 608 * The mutator updates the superblock flags. 609 */ 610 static int __begin_transaction_flags(struct dm_cache_metadata *cmd, 611 flags_mutator mutator) 612 { 613 int r; 614 struct cache_disk_superblock *disk_super; 615 struct dm_block *sblock; 616 617 r = superblock_lock(cmd, &sblock); 618 if (r) 619 return r; 620 621 disk_super = dm_block_data(sblock); 622 update_flags(disk_super, mutator); 623 read_superblock_fields(cmd, disk_super); 624 dm_bm_unlock(sblock); 625 626 return dm_bm_flush(cmd->bm); 627 } 628 629 static int __begin_transaction(struct dm_cache_metadata *cmd) 630 { 631 int r; 632 struct cache_disk_superblock *disk_super; 633 struct dm_block *sblock; 634 635 /* 636 * We re-read the superblock every time. Shouldn't need to do this 637 * really. 638 */ 639 r = superblock_read_lock(cmd, &sblock); 640 if (r) 641 return r; 642 643 disk_super = dm_block_data(sblock); 644 read_superblock_fields(cmd, disk_super); 645 dm_bm_unlock(sblock); 646 647 return 0; 648 } 649 650 static int __commit_transaction(struct dm_cache_metadata *cmd, 651 flags_mutator mutator) 652 { 653 int r; 654 struct cache_disk_superblock *disk_super; 655 struct dm_block *sblock; 656 657 /* 658 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 659 */ 660 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 661 662 if (separate_dirty_bits(cmd)) { 663 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root, 664 &cmd->dirty_root); 665 if (r) 666 return r; 667 } 668 669 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 670 &cmd->discard_root); 671 if (r) 672 return r; 673 674 r = dm_tm_pre_commit(cmd->tm); 675 if (r < 0) 676 return r; 677 678 r = __save_sm_root(cmd); 679 if (r) 680 return r; 681 682 r = superblock_lock(cmd, &sblock); 683 if (r) 684 return r; 685 686 disk_super = dm_block_data(sblock); 687 688 disk_super->flags = cpu_to_le32(cmd->flags); 689 if (mutator) 690 update_flags(disk_super, mutator); 691 692 disk_super->mapping_root = cpu_to_le64(cmd->root); 693 if (separate_dirty_bits(cmd)) 694 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); 695 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 696 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 697 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 698 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 699 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 700 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 701 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); 702 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); 703 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); 704 705 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 706 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 707 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 708 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 709 __copy_sm_root(cmd, disk_super); 710 711 return dm_tm_commit(cmd->tm, sblock); 712 } 713 714 /*----------------------------------------------------------------*/ 715 716 /* 717 * The mappings are held in a dm-array that has 64-bit values stored in 718 * little-endian format. The index is the cblock, the high 48bits of the 719 * value are the oblock and the low 16 bit the flags. 720 */ 721 #define FLAGS_MASK ((1 << 16) - 1) 722 723 static __le64 pack_value(dm_oblock_t block, unsigned flags) 724 { 725 uint64_t value = from_oblock(block); 726 value <<= 16; 727 value = value | (flags & FLAGS_MASK); 728 return cpu_to_le64(value); 729 } 730 731 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 732 { 733 uint64_t value = le64_to_cpu(value_le); 734 uint64_t b = value >> 16; 735 *block = to_oblock(b); 736 *flags = value & FLAGS_MASK; 737 } 738 739 /*----------------------------------------------------------------*/ 740 741 static struct dm_cache_metadata *metadata_open(struct block_device *bdev, 742 sector_t data_block_size, 743 bool may_format_device, 744 size_t policy_hint_size, 745 unsigned metadata_version) 746 { 747 int r; 748 struct dm_cache_metadata *cmd; 749 750 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 751 if (!cmd) { 752 DMERR("could not allocate metadata struct"); 753 return ERR_PTR(-ENOMEM); 754 } 755 756 cmd->version = metadata_version; 757 refcount_set(&cmd->ref_count, 1); 758 init_rwsem(&cmd->root_lock); 759 cmd->bdev = bdev; 760 cmd->data_block_size = data_block_size; 761 cmd->cache_blocks = 0; 762 cmd->policy_hint_size = policy_hint_size; 763 cmd->changed = true; 764 cmd->fail_io = false; 765 766 r = __create_persistent_data_objects(cmd, may_format_device); 767 if (r) { 768 kfree(cmd); 769 return ERR_PTR(r); 770 } 771 772 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 773 if (r < 0) { 774 dm_cache_metadata_close(cmd); 775 return ERR_PTR(r); 776 } 777 778 return cmd; 779 } 780 781 /* 782 * We keep a little list of ref counted metadata objects to prevent two 783 * different target instances creating separate bufio instances. This is 784 * an issue if a table is reloaded before the suspend. 785 */ 786 static DEFINE_MUTEX(table_lock); 787 static LIST_HEAD(table); 788 789 static struct dm_cache_metadata *lookup(struct block_device *bdev) 790 { 791 struct dm_cache_metadata *cmd; 792 793 list_for_each_entry(cmd, &table, list) 794 if (cmd->bdev == bdev) { 795 refcount_inc(&cmd->ref_count); 796 return cmd; 797 } 798 799 return NULL; 800 } 801 802 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev, 803 sector_t data_block_size, 804 bool may_format_device, 805 size_t policy_hint_size, 806 unsigned metadata_version) 807 { 808 struct dm_cache_metadata *cmd, *cmd2; 809 810 mutex_lock(&table_lock); 811 cmd = lookup(bdev); 812 mutex_unlock(&table_lock); 813 814 if (cmd) 815 return cmd; 816 817 cmd = metadata_open(bdev, data_block_size, may_format_device, 818 policy_hint_size, metadata_version); 819 if (!IS_ERR(cmd)) { 820 mutex_lock(&table_lock); 821 cmd2 = lookup(bdev); 822 if (cmd2) { 823 mutex_unlock(&table_lock); 824 __destroy_persistent_data_objects(cmd); 825 kfree(cmd); 826 return cmd2; 827 } 828 list_add(&cmd->list, &table); 829 mutex_unlock(&table_lock); 830 } 831 832 return cmd; 833 } 834 835 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size) 836 { 837 if (cmd->data_block_size != data_block_size) { 838 DMERR("data_block_size (%llu) different from that in metadata (%llu)", 839 (unsigned long long) data_block_size, 840 (unsigned long long) cmd->data_block_size); 841 return false; 842 } 843 844 return true; 845 } 846 847 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 848 sector_t data_block_size, 849 bool may_format_device, 850 size_t policy_hint_size, 851 unsigned metadata_version) 852 { 853 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device, 854 policy_hint_size, metadata_version); 855 856 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) { 857 dm_cache_metadata_close(cmd); 858 return ERR_PTR(-EINVAL); 859 } 860 861 return cmd; 862 } 863 864 void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 865 { 866 if (refcount_dec_and_test(&cmd->ref_count)) { 867 mutex_lock(&table_lock); 868 list_del(&cmd->list); 869 mutex_unlock(&table_lock); 870 871 if (!cmd->fail_io) 872 __destroy_persistent_data_objects(cmd); 873 kfree(cmd); 874 } 875 } 876 877 /* 878 * Checks that the given cache block is either unmapped or clean. 879 */ 880 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b, 881 bool *result) 882 { 883 int r; 884 __le64 value; 885 dm_oblock_t ob; 886 unsigned flags; 887 888 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value); 889 if (r) 890 return r; 891 892 unpack_value(value, &ob, &flags); 893 *result = !((flags & M_VALID) && (flags & M_DIRTY)); 894 895 return 0; 896 } 897 898 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd, 899 dm_cblock_t begin, dm_cblock_t end, 900 bool *result) 901 { 902 int r; 903 *result = true; 904 905 while (begin != end) { 906 r = block_clean_combined_dirty(cmd, begin, result); 907 if (r) { 908 DMERR("block_clean_combined_dirty failed"); 909 return r; 910 } 911 912 if (!*result) { 913 DMERR("cache block %llu is dirty", 914 (unsigned long long) from_cblock(begin)); 915 return 0; 916 } 917 918 begin = to_cblock(from_cblock(begin) + 1); 919 } 920 921 return 0; 922 } 923 924 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd, 925 dm_cblock_t begin, dm_cblock_t end, 926 bool *result) 927 { 928 int r; 929 bool dirty_flag; 930 *result = true; 931 932 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, 933 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor); 934 if (r) { 935 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__); 936 return r; 937 } 938 939 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin)); 940 if (r) { 941 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__); 942 dm_bitset_cursor_end(&cmd->dirty_cursor); 943 return r; 944 } 945 946 while (begin != end) { 947 /* 948 * We assume that unmapped blocks have their dirty bit 949 * cleared. 950 */ 951 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor); 952 if (dirty_flag) { 953 DMERR("%s: cache block %llu is dirty", __func__, 954 (unsigned long long) from_cblock(begin)); 955 dm_bitset_cursor_end(&cmd->dirty_cursor); 956 *result = false; 957 return 0; 958 } 959 960 begin = to_cblock(from_cblock(begin) + 1); 961 if (begin == end) 962 break; 963 964 r = dm_bitset_cursor_next(&cmd->dirty_cursor); 965 if (r) { 966 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__); 967 dm_bitset_cursor_end(&cmd->dirty_cursor); 968 return r; 969 } 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 = -EINVAL; 1629 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1630 clear_clean_shutdown); 1631 1632 WRITE_LOCK(cmd); 1633 if (cmd->fail_io) 1634 goto out; 1635 1636 r = __commit_transaction(cmd, mutator); 1637 if (r) 1638 goto out; 1639 1640 r = __begin_transaction(cmd); 1641 out: 1642 WRITE_UNLOCK(cmd); 1643 return r; 1644 } 1645 1646 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1647 dm_block_t *result) 1648 { 1649 int r = -EINVAL; 1650 1651 READ_LOCK(cmd); 1652 if (!cmd->fail_io) 1653 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1654 READ_UNLOCK(cmd); 1655 1656 return r; 1657 } 1658 1659 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1660 dm_block_t *result) 1661 { 1662 int r = -EINVAL; 1663 1664 READ_LOCK(cmd); 1665 if (!cmd->fail_io) 1666 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1667 READ_UNLOCK(cmd); 1668 1669 return r; 1670 } 1671 1672 /*----------------------------------------------------------------*/ 1673 1674 static int get_hint(uint32_t index, void *value_le, void *context) 1675 { 1676 uint32_t value; 1677 struct dm_cache_policy *policy = context; 1678 1679 value = policy_get_hint(policy, to_cblock(index)); 1680 *((__le32 *) value_le) = cpu_to_le32(value); 1681 1682 return 0; 1683 } 1684 1685 /* 1686 * It's quicker to always delete the hint array, and recreate with 1687 * dm_array_new(). 1688 */ 1689 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1690 { 1691 int r; 1692 size_t hint_size; 1693 const char *policy_name = dm_cache_policy_get_name(policy); 1694 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1695 1696 if (!policy_name[0] || 1697 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1698 return -EINVAL; 1699 1700 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1701 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); 1702 1703 hint_size = dm_cache_policy_get_hint_size(policy); 1704 if (!hint_size) 1705 return 0; /* short-circuit hints initialization */ 1706 cmd->policy_hint_size = hint_size; 1707 1708 if (cmd->hint_root) { 1709 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1710 if (r) 1711 return r; 1712 } 1713 1714 return dm_array_new(&cmd->hint_info, &cmd->hint_root, 1715 from_cblock(cmd->cache_blocks), 1716 get_hint, policy); 1717 } 1718 1719 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1720 { 1721 int r; 1722 1723 WRITE_LOCK(cmd); 1724 r = write_hints(cmd, policy); 1725 WRITE_UNLOCK(cmd); 1726 1727 return r; 1728 } 1729 1730 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result) 1731 { 1732 int r; 1733 1734 READ_LOCK(cmd); 1735 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result); 1736 READ_UNLOCK(cmd); 1737 1738 return r; 1739 } 1740 1741 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd) 1742 { 1743 WRITE_LOCK_VOID(cmd); 1744 dm_bm_set_read_only(cmd->bm); 1745 WRITE_UNLOCK(cmd); 1746 } 1747 1748 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd) 1749 { 1750 WRITE_LOCK_VOID(cmd); 1751 dm_bm_set_read_write(cmd->bm); 1752 WRITE_UNLOCK(cmd); 1753 } 1754 1755 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd) 1756 { 1757 int r; 1758 struct dm_block *sblock; 1759 struct cache_disk_superblock *disk_super; 1760 1761 WRITE_LOCK(cmd); 1762 set_bit(NEEDS_CHECK, &cmd->flags); 1763 1764 r = superblock_lock(cmd, &sblock); 1765 if (r) { 1766 DMERR("couldn't read superblock"); 1767 goto out; 1768 } 1769 1770 disk_super = dm_block_data(sblock); 1771 disk_super->flags = cpu_to_le32(cmd->flags); 1772 1773 dm_bm_unlock(sblock); 1774 1775 out: 1776 WRITE_UNLOCK(cmd); 1777 return r; 1778 } 1779 1780 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result) 1781 { 1782 READ_LOCK(cmd); 1783 *result = !!test_bit(NEEDS_CHECK, &cmd->flags); 1784 READ_UNLOCK(cmd); 1785 1786 return 0; 1787 } 1788 1789 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd) 1790 { 1791 int r; 1792 1793 WRITE_LOCK(cmd); 1794 __destroy_persistent_data_objects(cmd); 1795 r = __create_persistent_data_objects(cmd, false); 1796 if (r) 1797 cmd->fail_io = true; 1798 WRITE_UNLOCK(cmd); 1799 1800 return r; 1801 } 1802