1 #include "dm.h" 2 #include "persistent-data/dm-transaction-manager.h" 3 #include "persistent-data/dm-bitset.h" 4 #include "persistent-data/dm-space-map.h" 5 6 #include <linux/dm-io.h> 7 #include <linux/dm-kcopyd.h> 8 #include <linux/init.h> 9 #include <linux/mempool.h> 10 #include <linux/module.h> 11 #include <linux/slab.h> 12 #include <linux/vmalloc.h> 13 14 #define DM_MSG_PREFIX "era" 15 16 #define SUPERBLOCK_LOCATION 0 17 #define SUPERBLOCK_MAGIC 2126579579 18 #define SUPERBLOCK_CSUM_XOR 146538381 19 #define MIN_ERA_VERSION 1 20 #define MAX_ERA_VERSION 1 21 #define INVALID_WRITESET_ROOT SUPERBLOCK_LOCATION 22 #define MIN_BLOCK_SIZE 8 23 24 /*---------------------------------------------------------------- 25 * Writeset 26 *--------------------------------------------------------------*/ 27 struct writeset_metadata { 28 uint32_t nr_bits; 29 dm_block_t root; 30 }; 31 32 struct writeset { 33 struct writeset_metadata md; 34 35 /* 36 * An in core copy of the bits to save constantly doing look ups on 37 * disk. 38 */ 39 unsigned long *bits; 40 }; 41 42 /* 43 * This does not free off the on disk bitset as this will normally be done 44 * after digesting into the era array. 45 */ 46 static void writeset_free(struct writeset *ws) 47 { 48 vfree(ws->bits); 49 } 50 51 static int setup_on_disk_bitset(struct dm_disk_bitset *info, 52 unsigned nr_bits, dm_block_t *root) 53 { 54 int r; 55 56 r = dm_bitset_empty(info, root); 57 if (r) 58 return r; 59 60 return dm_bitset_resize(info, *root, 0, nr_bits, false, root); 61 } 62 63 static size_t bitset_size(unsigned nr_bits) 64 { 65 return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG); 66 } 67 68 /* 69 * Allocates memory for the in core bitset. 70 */ 71 static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks) 72 { 73 ws->md.nr_bits = nr_blocks; 74 ws->md.root = INVALID_WRITESET_ROOT; 75 ws->bits = vzalloc(bitset_size(nr_blocks)); 76 if (!ws->bits) { 77 DMERR("%s: couldn't allocate in memory bitset", __func__); 78 return -ENOMEM; 79 } 80 81 return 0; 82 } 83 84 /* 85 * Wipes the in-core bitset, and creates a new on disk bitset. 86 */ 87 static int writeset_init(struct dm_disk_bitset *info, struct writeset *ws) 88 { 89 int r; 90 91 memset(ws->bits, 0, bitset_size(ws->md.nr_bits)); 92 93 r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root); 94 if (r) { 95 DMERR("%s: setup_on_disk_bitset failed", __func__); 96 return r; 97 } 98 99 return 0; 100 } 101 102 static bool writeset_marked(struct writeset *ws, dm_block_t block) 103 { 104 return test_bit(block, ws->bits); 105 } 106 107 static int writeset_marked_on_disk(struct dm_disk_bitset *info, 108 struct writeset_metadata *m, dm_block_t block, 109 bool *result) 110 { 111 dm_block_t old = m->root; 112 113 /* 114 * The bitset was flushed when it was archived, so we know there'll 115 * be no change to the root. 116 */ 117 int r = dm_bitset_test_bit(info, m->root, block, &m->root, result); 118 if (r) { 119 DMERR("%s: dm_bitset_test_bit failed", __func__); 120 return r; 121 } 122 123 BUG_ON(m->root != old); 124 125 return r; 126 } 127 128 /* 129 * Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was. 130 */ 131 static int writeset_test_and_set(struct dm_disk_bitset *info, 132 struct writeset *ws, uint32_t block) 133 { 134 int r; 135 136 if (!test_and_set_bit(block, ws->bits)) { 137 r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root); 138 if (r) { 139 /* FIXME: fail mode */ 140 return r; 141 } 142 143 return 0; 144 } 145 146 return 1; 147 } 148 149 /*---------------------------------------------------------------- 150 * On disk metadata layout 151 *--------------------------------------------------------------*/ 152 #define SPACE_MAP_ROOT_SIZE 128 153 #define UUID_LEN 16 154 155 struct writeset_disk { 156 __le32 nr_bits; 157 __le64 root; 158 } __packed; 159 160 struct superblock_disk { 161 __le32 csum; 162 __le32 flags; 163 __le64 blocknr; 164 165 __u8 uuid[UUID_LEN]; 166 __le64 magic; 167 __le32 version; 168 169 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 170 171 __le32 data_block_size; 172 __le32 metadata_block_size; 173 __le32 nr_blocks; 174 175 __le32 current_era; 176 struct writeset_disk current_writeset; 177 178 /* 179 * Only these two fields are valid within the metadata snapshot. 180 */ 181 __le64 writeset_tree_root; 182 __le64 era_array_root; 183 184 __le64 metadata_snap; 185 } __packed; 186 187 /*---------------------------------------------------------------- 188 * Superblock validation 189 *--------------------------------------------------------------*/ 190 static void sb_prepare_for_write(struct dm_block_validator *v, 191 struct dm_block *b, 192 size_t sb_block_size) 193 { 194 struct superblock_disk *disk = dm_block_data(b); 195 196 disk->blocknr = cpu_to_le64(dm_block_location(b)); 197 disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags, 198 sb_block_size - sizeof(__le32), 199 SUPERBLOCK_CSUM_XOR)); 200 } 201 202 static int check_metadata_version(struct superblock_disk *disk) 203 { 204 uint32_t metadata_version = le32_to_cpu(disk->version); 205 if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) { 206 DMERR("Era metadata version %u found, but only versions between %u and %u supported.", 207 metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION); 208 return -EINVAL; 209 } 210 211 return 0; 212 } 213 214 static int sb_check(struct dm_block_validator *v, 215 struct dm_block *b, 216 size_t sb_block_size) 217 { 218 struct superblock_disk *disk = dm_block_data(b); 219 __le32 csum_le; 220 221 if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) { 222 DMERR("sb_check failed: blocknr %llu: wanted %llu", 223 le64_to_cpu(disk->blocknr), 224 (unsigned long long)dm_block_location(b)); 225 return -ENOTBLK; 226 } 227 228 if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) { 229 DMERR("sb_check failed: magic %llu: wanted %llu", 230 le64_to_cpu(disk->magic), 231 (unsigned long long) SUPERBLOCK_MAGIC); 232 return -EILSEQ; 233 } 234 235 csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags, 236 sb_block_size - sizeof(__le32), 237 SUPERBLOCK_CSUM_XOR)); 238 if (csum_le != disk->csum) { 239 DMERR("sb_check failed: csum %u: wanted %u", 240 le32_to_cpu(csum_le), le32_to_cpu(disk->csum)); 241 return -EILSEQ; 242 } 243 244 return check_metadata_version(disk); 245 } 246 247 static struct dm_block_validator sb_validator = { 248 .name = "superblock", 249 .prepare_for_write = sb_prepare_for_write, 250 .check = sb_check 251 }; 252 253 /*---------------------------------------------------------------- 254 * Low level metadata handling 255 *--------------------------------------------------------------*/ 256 #define DM_ERA_METADATA_BLOCK_SIZE 4096 257 #define ERA_MAX_CONCURRENT_LOCKS 5 258 259 struct era_metadata { 260 struct block_device *bdev; 261 struct dm_block_manager *bm; 262 struct dm_space_map *sm; 263 struct dm_transaction_manager *tm; 264 265 dm_block_t block_size; 266 uint32_t nr_blocks; 267 268 uint32_t current_era; 269 270 /* 271 * We preallocate 2 writesets. When an era rolls over we 272 * switch between them. This means the allocation is done at 273 * preresume time, rather than on the io path. 274 */ 275 struct writeset writesets[2]; 276 struct writeset *current_writeset; 277 278 dm_block_t writeset_tree_root; 279 dm_block_t era_array_root; 280 281 struct dm_disk_bitset bitset_info; 282 struct dm_btree_info writeset_tree_info; 283 struct dm_array_info era_array_info; 284 285 dm_block_t metadata_snap; 286 287 /* 288 * A flag that is set whenever a writeset has been archived. 289 */ 290 bool archived_writesets; 291 292 /* 293 * Reading the space map root can fail, so we read it into this 294 * buffer before the superblock is locked and updated. 295 */ 296 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 297 }; 298 299 static int superblock_read_lock(struct era_metadata *md, 300 struct dm_block **sblock) 301 { 302 return dm_bm_read_lock(md->bm, SUPERBLOCK_LOCATION, 303 &sb_validator, sblock); 304 } 305 306 static int superblock_lock_zero(struct era_metadata *md, 307 struct dm_block **sblock) 308 { 309 return dm_bm_write_lock_zero(md->bm, SUPERBLOCK_LOCATION, 310 &sb_validator, sblock); 311 } 312 313 static int superblock_lock(struct era_metadata *md, 314 struct dm_block **sblock) 315 { 316 return dm_bm_write_lock(md->bm, SUPERBLOCK_LOCATION, 317 &sb_validator, sblock); 318 } 319 320 /* FIXME: duplication with cache and thin */ 321 static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result) 322 { 323 int r; 324 unsigned i; 325 struct dm_block *b; 326 __le64 *data_le, zero = cpu_to_le64(0); 327 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 328 329 /* 330 * We can't use a validator here - it may be all zeroes. 331 */ 332 r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &b); 333 if (r) 334 return r; 335 336 data_le = dm_block_data(b); 337 *result = true; 338 for (i = 0; i < sb_block_size; i++) { 339 if (data_le[i] != zero) { 340 *result = false; 341 break; 342 } 343 } 344 345 dm_bm_unlock(b); 346 347 return 0; 348 } 349 350 /*----------------------------------------------------------------*/ 351 352 static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk) 353 { 354 disk->nr_bits = cpu_to_le32(core->nr_bits); 355 disk->root = cpu_to_le64(core->root); 356 } 357 358 static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core) 359 { 360 core->nr_bits = le32_to_cpu(disk->nr_bits); 361 core->root = le64_to_cpu(disk->root); 362 } 363 364 static void ws_inc(void *context, const void *value) 365 { 366 struct era_metadata *md = context; 367 struct writeset_disk ws_d; 368 dm_block_t b; 369 370 memcpy(&ws_d, value, sizeof(ws_d)); 371 b = le64_to_cpu(ws_d.root); 372 373 dm_tm_inc(md->tm, b); 374 } 375 376 static void ws_dec(void *context, const void *value) 377 { 378 struct era_metadata *md = context; 379 struct writeset_disk ws_d; 380 dm_block_t b; 381 382 memcpy(&ws_d, value, sizeof(ws_d)); 383 b = le64_to_cpu(ws_d.root); 384 385 dm_bitset_del(&md->bitset_info, b); 386 } 387 388 static int ws_eq(void *context, const void *value1, const void *value2) 389 { 390 return !memcmp(value1, value2, sizeof(struct writeset_metadata)); 391 } 392 393 /*----------------------------------------------------------------*/ 394 395 static void setup_writeset_tree_info(struct era_metadata *md) 396 { 397 struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type; 398 md->writeset_tree_info.tm = md->tm; 399 md->writeset_tree_info.levels = 1; 400 vt->context = md; 401 vt->size = sizeof(struct writeset_disk); 402 vt->inc = ws_inc; 403 vt->dec = ws_dec; 404 vt->equal = ws_eq; 405 } 406 407 static void setup_era_array_info(struct era_metadata *md) 408 409 { 410 struct dm_btree_value_type vt; 411 vt.context = NULL; 412 vt.size = sizeof(__le32); 413 vt.inc = NULL; 414 vt.dec = NULL; 415 vt.equal = NULL; 416 417 dm_array_info_init(&md->era_array_info, md->tm, &vt); 418 } 419 420 static void setup_infos(struct era_metadata *md) 421 { 422 dm_disk_bitset_init(md->tm, &md->bitset_info); 423 setup_writeset_tree_info(md); 424 setup_era_array_info(md); 425 } 426 427 /*----------------------------------------------------------------*/ 428 429 static int create_fresh_metadata(struct era_metadata *md) 430 { 431 int r; 432 433 r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION, 434 &md->tm, &md->sm); 435 if (r < 0) { 436 DMERR("dm_tm_create_with_sm failed"); 437 return r; 438 } 439 440 setup_infos(md); 441 442 r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root); 443 if (r) { 444 DMERR("couldn't create new writeset tree"); 445 goto bad; 446 } 447 448 r = dm_array_empty(&md->era_array_info, &md->era_array_root); 449 if (r) { 450 DMERR("couldn't create era array"); 451 goto bad; 452 } 453 454 return 0; 455 456 bad: 457 dm_sm_destroy(md->sm); 458 dm_tm_destroy(md->tm); 459 460 return r; 461 } 462 463 static int save_sm_root(struct era_metadata *md) 464 { 465 int r; 466 size_t metadata_len; 467 468 r = dm_sm_root_size(md->sm, &metadata_len); 469 if (r < 0) 470 return r; 471 472 return dm_sm_copy_root(md->sm, &md->metadata_space_map_root, 473 metadata_len); 474 } 475 476 static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk) 477 { 478 memcpy(&disk->metadata_space_map_root, 479 &md->metadata_space_map_root, 480 sizeof(md->metadata_space_map_root)); 481 } 482 483 /* 484 * Writes a superblock, including the static fields that don't get updated 485 * with every commit (possible optimisation here). 'md' should be fully 486 * constructed when this is called. 487 */ 488 static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk) 489 { 490 disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC); 491 disk->flags = cpu_to_le32(0ul); 492 493 /* FIXME: can't keep blanking the uuid (uuid is currently unused though) */ 494 memset(disk->uuid, 0, sizeof(disk->uuid)); 495 disk->version = cpu_to_le32(MAX_ERA_VERSION); 496 497 copy_sm_root(md, disk); 498 499 disk->data_block_size = cpu_to_le32(md->block_size); 500 disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); 501 disk->nr_blocks = cpu_to_le32(md->nr_blocks); 502 disk->current_era = cpu_to_le32(md->current_era); 503 504 ws_pack(&md->current_writeset->md, &disk->current_writeset); 505 disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root); 506 disk->era_array_root = cpu_to_le64(md->era_array_root); 507 disk->metadata_snap = cpu_to_le64(md->metadata_snap); 508 } 509 510 static int write_superblock(struct era_metadata *md) 511 { 512 int r; 513 struct dm_block *sblock; 514 struct superblock_disk *disk; 515 516 r = save_sm_root(md); 517 if (r) { 518 DMERR("%s: save_sm_root failed", __func__); 519 return r; 520 } 521 522 r = superblock_lock_zero(md, &sblock); 523 if (r) 524 return r; 525 526 disk = dm_block_data(sblock); 527 prepare_superblock(md, disk); 528 529 return dm_tm_commit(md->tm, sblock); 530 } 531 532 /* 533 * Assumes block_size and the infos are set. 534 */ 535 static int format_metadata(struct era_metadata *md) 536 { 537 int r; 538 539 r = create_fresh_metadata(md); 540 if (r) 541 return r; 542 543 r = write_superblock(md); 544 if (r) { 545 dm_sm_destroy(md->sm); 546 dm_tm_destroy(md->tm); 547 return r; 548 } 549 550 return 0; 551 } 552 553 static int open_metadata(struct era_metadata *md) 554 { 555 int r; 556 struct dm_block *sblock; 557 struct superblock_disk *disk; 558 559 r = superblock_read_lock(md, &sblock); 560 if (r) { 561 DMERR("couldn't read_lock superblock"); 562 return r; 563 } 564 565 disk = dm_block_data(sblock); 566 r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION, 567 disk->metadata_space_map_root, 568 sizeof(disk->metadata_space_map_root), 569 &md->tm, &md->sm); 570 if (r) { 571 DMERR("dm_tm_open_with_sm failed"); 572 goto bad; 573 } 574 575 setup_infos(md); 576 577 md->block_size = le32_to_cpu(disk->data_block_size); 578 md->nr_blocks = le32_to_cpu(disk->nr_blocks); 579 md->current_era = le32_to_cpu(disk->current_era); 580 581 md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root); 582 md->era_array_root = le64_to_cpu(disk->era_array_root); 583 md->metadata_snap = le64_to_cpu(disk->metadata_snap); 584 md->archived_writesets = true; 585 586 dm_bm_unlock(sblock); 587 588 return 0; 589 590 bad: 591 dm_bm_unlock(sblock); 592 return r; 593 } 594 595 static int open_or_format_metadata(struct era_metadata *md, 596 bool may_format) 597 { 598 int r; 599 bool unformatted = false; 600 601 r = superblock_all_zeroes(md->bm, &unformatted); 602 if (r) 603 return r; 604 605 if (unformatted) 606 return may_format ? format_metadata(md) : -EPERM; 607 608 return open_metadata(md); 609 } 610 611 static int create_persistent_data_objects(struct era_metadata *md, 612 bool may_format) 613 { 614 int r; 615 616 md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE, 617 ERA_MAX_CONCURRENT_LOCKS); 618 if (IS_ERR(md->bm)) { 619 DMERR("could not create block manager"); 620 return PTR_ERR(md->bm); 621 } 622 623 r = open_or_format_metadata(md, may_format); 624 if (r) 625 dm_block_manager_destroy(md->bm); 626 627 return r; 628 } 629 630 static void destroy_persistent_data_objects(struct era_metadata *md) 631 { 632 dm_sm_destroy(md->sm); 633 dm_tm_destroy(md->tm); 634 dm_block_manager_destroy(md->bm); 635 } 636 637 /* 638 * This waits until all era_map threads have picked up the new filter. 639 */ 640 static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset) 641 { 642 rcu_assign_pointer(md->current_writeset, new_writeset); 643 synchronize_rcu(); 644 } 645 646 /*---------------------------------------------------------------- 647 * Writesets get 'digested' into the main era array. 648 * 649 * We're using a coroutine here so the worker thread can do the digestion, 650 * thus avoiding synchronisation of the metadata. Digesting a whole 651 * writeset in one go would cause too much latency. 652 *--------------------------------------------------------------*/ 653 struct digest { 654 uint32_t era; 655 unsigned nr_bits, current_bit; 656 struct writeset_metadata writeset; 657 __le32 value; 658 struct dm_disk_bitset info; 659 660 int (*step)(struct era_metadata *, struct digest *); 661 }; 662 663 static int metadata_digest_lookup_writeset(struct era_metadata *md, 664 struct digest *d); 665 666 static int metadata_digest_remove_writeset(struct era_metadata *md, 667 struct digest *d) 668 { 669 int r; 670 uint64_t key = d->era; 671 672 r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root, 673 &key, &md->writeset_tree_root); 674 if (r) { 675 DMERR("%s: dm_btree_remove failed", __func__); 676 return r; 677 } 678 679 d->step = metadata_digest_lookup_writeset; 680 return 0; 681 } 682 683 #define INSERTS_PER_STEP 100 684 685 static int metadata_digest_transcribe_writeset(struct era_metadata *md, 686 struct digest *d) 687 { 688 int r; 689 bool marked; 690 unsigned b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits); 691 692 for (b = d->current_bit; b < e; b++) { 693 r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked); 694 if (r) { 695 DMERR("%s: writeset_marked_on_disk failed", __func__); 696 return r; 697 } 698 699 if (!marked) 700 continue; 701 702 __dm_bless_for_disk(&d->value); 703 r = dm_array_set_value(&md->era_array_info, md->era_array_root, 704 b, &d->value, &md->era_array_root); 705 if (r) { 706 DMERR("%s: dm_array_set_value failed", __func__); 707 return r; 708 } 709 } 710 711 if (b == d->nr_bits) 712 d->step = metadata_digest_remove_writeset; 713 else 714 d->current_bit = b; 715 716 return 0; 717 } 718 719 static int metadata_digest_lookup_writeset(struct era_metadata *md, 720 struct digest *d) 721 { 722 int r; 723 uint64_t key; 724 struct writeset_disk disk; 725 726 r = dm_btree_find_lowest_key(&md->writeset_tree_info, 727 md->writeset_tree_root, &key); 728 if (r < 0) 729 return r; 730 731 d->era = key; 732 733 r = dm_btree_lookup(&md->writeset_tree_info, 734 md->writeset_tree_root, &key, &disk); 735 if (r) { 736 if (r == -ENODATA) { 737 d->step = NULL; 738 return 0; 739 } 740 741 DMERR("%s: dm_btree_lookup failed", __func__); 742 return r; 743 } 744 745 ws_unpack(&disk, &d->writeset); 746 d->value = cpu_to_le32(key); 747 748 d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks); 749 d->current_bit = 0; 750 d->step = metadata_digest_transcribe_writeset; 751 752 return 0; 753 } 754 755 static int metadata_digest_start(struct era_metadata *md, struct digest *d) 756 { 757 if (d->step) 758 return 0; 759 760 memset(d, 0, sizeof(*d)); 761 762 /* 763 * We initialise another bitset info to avoid any caching side 764 * effects with the previous one. 765 */ 766 dm_disk_bitset_init(md->tm, &d->info); 767 d->step = metadata_digest_lookup_writeset; 768 769 return 0; 770 } 771 772 /*---------------------------------------------------------------- 773 * High level metadata interface. Target methods should use these, and not 774 * the lower level ones. 775 *--------------------------------------------------------------*/ 776 static struct era_metadata *metadata_open(struct block_device *bdev, 777 sector_t block_size, 778 bool may_format) 779 { 780 int r; 781 struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL); 782 783 if (!md) 784 return NULL; 785 786 md->bdev = bdev; 787 md->block_size = block_size; 788 789 md->writesets[0].md.root = INVALID_WRITESET_ROOT; 790 md->writesets[1].md.root = INVALID_WRITESET_ROOT; 791 md->current_writeset = &md->writesets[0]; 792 793 r = create_persistent_data_objects(md, may_format); 794 if (r) { 795 kfree(md); 796 return ERR_PTR(r); 797 } 798 799 return md; 800 } 801 802 static void metadata_close(struct era_metadata *md) 803 { 804 destroy_persistent_data_objects(md); 805 kfree(md); 806 } 807 808 static bool valid_nr_blocks(dm_block_t n) 809 { 810 /* 811 * dm_bitset restricts us to 2^32. test_bit & co. restrict us 812 * further to 2^31 - 1 813 */ 814 return n < (1ull << 31); 815 } 816 817 static int metadata_resize(struct era_metadata *md, void *arg) 818 { 819 int r; 820 dm_block_t *new_size = arg; 821 __le32 value; 822 823 if (!valid_nr_blocks(*new_size)) { 824 DMERR("Invalid number of origin blocks %llu", 825 (unsigned long long) *new_size); 826 return -EINVAL; 827 } 828 829 writeset_free(&md->writesets[0]); 830 writeset_free(&md->writesets[1]); 831 832 r = writeset_alloc(&md->writesets[0], *new_size); 833 if (r) { 834 DMERR("%s: writeset_alloc failed for writeset 0", __func__); 835 return r; 836 } 837 838 r = writeset_alloc(&md->writesets[1], *new_size); 839 if (r) { 840 DMERR("%s: writeset_alloc failed for writeset 1", __func__); 841 return r; 842 } 843 844 value = cpu_to_le32(0u); 845 __dm_bless_for_disk(&value); 846 r = dm_array_resize(&md->era_array_info, md->era_array_root, 847 md->nr_blocks, *new_size, 848 &value, &md->era_array_root); 849 if (r) { 850 DMERR("%s: dm_array_resize failed", __func__); 851 return r; 852 } 853 854 md->nr_blocks = *new_size; 855 return 0; 856 } 857 858 static int metadata_era_archive(struct era_metadata *md) 859 { 860 int r; 861 uint64_t keys[1]; 862 struct writeset_disk value; 863 864 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root, 865 &md->current_writeset->md.root); 866 if (r) { 867 DMERR("%s: dm_bitset_flush failed", __func__); 868 return r; 869 } 870 871 ws_pack(&md->current_writeset->md, &value); 872 md->current_writeset->md.root = INVALID_WRITESET_ROOT; 873 874 keys[0] = md->current_era; 875 __dm_bless_for_disk(&value); 876 r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root, 877 keys, &value, &md->writeset_tree_root); 878 if (r) { 879 DMERR("%s: couldn't insert writeset into btree", __func__); 880 /* FIXME: fail mode */ 881 return r; 882 } 883 884 md->archived_writesets = true; 885 886 return 0; 887 } 888 889 static struct writeset *next_writeset(struct era_metadata *md) 890 { 891 return (md->current_writeset == &md->writesets[0]) ? 892 &md->writesets[1] : &md->writesets[0]; 893 } 894 895 static int metadata_new_era(struct era_metadata *md) 896 { 897 int r; 898 struct writeset *new_writeset = next_writeset(md); 899 900 r = writeset_init(&md->bitset_info, new_writeset); 901 if (r) { 902 DMERR("%s: writeset_init failed", __func__); 903 return r; 904 } 905 906 swap_writeset(md, new_writeset); 907 md->current_era++; 908 909 return 0; 910 } 911 912 static int metadata_era_rollover(struct era_metadata *md) 913 { 914 int r; 915 916 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) { 917 r = metadata_era_archive(md); 918 if (r) { 919 DMERR("%s: metadata_archive_era failed", __func__); 920 /* FIXME: fail mode? */ 921 return r; 922 } 923 } 924 925 r = metadata_new_era(md); 926 if (r) { 927 DMERR("%s: new era failed", __func__); 928 /* FIXME: fail mode */ 929 return r; 930 } 931 932 return 0; 933 } 934 935 static bool metadata_current_marked(struct era_metadata *md, dm_block_t block) 936 { 937 bool r; 938 struct writeset *ws; 939 940 rcu_read_lock(); 941 ws = rcu_dereference(md->current_writeset); 942 r = writeset_marked(ws, block); 943 rcu_read_unlock(); 944 945 return r; 946 } 947 948 static int metadata_commit(struct era_metadata *md) 949 { 950 int r; 951 struct dm_block *sblock; 952 953 if (md->current_writeset->md.root != SUPERBLOCK_LOCATION) { 954 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root, 955 &md->current_writeset->md.root); 956 if (r) { 957 DMERR("%s: bitset flush failed", __func__); 958 return r; 959 } 960 } 961 962 r = dm_tm_pre_commit(md->tm); 963 if (r) { 964 DMERR("%s: pre commit failed", __func__); 965 return r; 966 } 967 968 r = save_sm_root(md); 969 if (r) { 970 DMERR("%s: save_sm_root failed", __func__); 971 return r; 972 } 973 974 r = superblock_lock(md, &sblock); 975 if (r) { 976 DMERR("%s: superblock lock failed", __func__); 977 return r; 978 } 979 980 prepare_superblock(md, dm_block_data(sblock)); 981 982 return dm_tm_commit(md->tm, sblock); 983 } 984 985 static int metadata_checkpoint(struct era_metadata *md) 986 { 987 /* 988 * For now we just rollover, but later I want to put a check in to 989 * avoid this if the filter is still pretty fresh. 990 */ 991 return metadata_era_rollover(md); 992 } 993 994 /* 995 * Metadata snapshots allow userland to access era data. 996 */ 997 static int metadata_take_snap(struct era_metadata *md) 998 { 999 int r, inc; 1000 struct dm_block *clone; 1001 1002 if (md->metadata_snap != SUPERBLOCK_LOCATION) { 1003 DMERR("%s: metadata snapshot already exists", __func__); 1004 return -EINVAL; 1005 } 1006 1007 r = metadata_era_rollover(md); 1008 if (r) { 1009 DMERR("%s: era rollover failed", __func__); 1010 return r; 1011 } 1012 1013 r = metadata_commit(md); 1014 if (r) { 1015 DMERR("%s: pre commit failed", __func__); 1016 return r; 1017 } 1018 1019 r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION); 1020 if (r) { 1021 DMERR("%s: couldn't increment superblock", __func__); 1022 return r; 1023 } 1024 1025 r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION, 1026 &sb_validator, &clone, &inc); 1027 if (r) { 1028 DMERR("%s: couldn't shadow superblock", __func__); 1029 dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION); 1030 return r; 1031 } 1032 BUG_ON(!inc); 1033 1034 r = dm_sm_inc_block(md->sm, md->writeset_tree_root); 1035 if (r) { 1036 DMERR("%s: couldn't inc writeset tree root", __func__); 1037 dm_tm_unlock(md->tm, clone); 1038 return r; 1039 } 1040 1041 r = dm_sm_inc_block(md->sm, md->era_array_root); 1042 if (r) { 1043 DMERR("%s: couldn't inc era tree root", __func__); 1044 dm_sm_dec_block(md->sm, md->writeset_tree_root); 1045 dm_tm_unlock(md->tm, clone); 1046 return r; 1047 } 1048 1049 md->metadata_snap = dm_block_location(clone); 1050 1051 dm_tm_unlock(md->tm, clone); 1052 1053 return 0; 1054 } 1055 1056 static int metadata_drop_snap(struct era_metadata *md) 1057 { 1058 int r; 1059 dm_block_t location; 1060 struct dm_block *clone; 1061 struct superblock_disk *disk; 1062 1063 if (md->metadata_snap == SUPERBLOCK_LOCATION) { 1064 DMERR("%s: no snap to drop", __func__); 1065 return -EINVAL; 1066 } 1067 1068 r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone); 1069 if (r) { 1070 DMERR("%s: couldn't read lock superblock clone", __func__); 1071 return r; 1072 } 1073 1074 /* 1075 * Whatever happens now we'll commit with no record of the metadata 1076 * snap. 1077 */ 1078 md->metadata_snap = SUPERBLOCK_LOCATION; 1079 1080 disk = dm_block_data(clone); 1081 r = dm_btree_del(&md->writeset_tree_info, 1082 le64_to_cpu(disk->writeset_tree_root)); 1083 if (r) { 1084 DMERR("%s: error deleting writeset tree clone", __func__); 1085 dm_tm_unlock(md->tm, clone); 1086 return r; 1087 } 1088 1089 r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root)); 1090 if (r) { 1091 DMERR("%s: error deleting era array clone", __func__); 1092 dm_tm_unlock(md->tm, clone); 1093 return r; 1094 } 1095 1096 location = dm_block_location(clone); 1097 dm_tm_unlock(md->tm, clone); 1098 1099 return dm_sm_dec_block(md->sm, location); 1100 } 1101 1102 struct metadata_stats { 1103 dm_block_t used; 1104 dm_block_t total; 1105 dm_block_t snap; 1106 uint32_t era; 1107 }; 1108 1109 static int metadata_get_stats(struct era_metadata *md, void *ptr) 1110 { 1111 int r; 1112 struct metadata_stats *s = ptr; 1113 dm_block_t nr_free, nr_total; 1114 1115 r = dm_sm_get_nr_free(md->sm, &nr_free); 1116 if (r) { 1117 DMERR("dm_sm_get_nr_free returned %d", r); 1118 return r; 1119 } 1120 1121 r = dm_sm_get_nr_blocks(md->sm, &nr_total); 1122 if (r) { 1123 DMERR("dm_pool_get_metadata_dev_size returned %d", r); 1124 return r; 1125 } 1126 1127 s->used = nr_total - nr_free; 1128 s->total = nr_total; 1129 s->snap = md->metadata_snap; 1130 s->era = md->current_era; 1131 1132 return 0; 1133 } 1134 1135 /*----------------------------------------------------------------*/ 1136 1137 struct era { 1138 struct dm_target *ti; 1139 struct dm_target_callbacks callbacks; 1140 1141 struct dm_dev *metadata_dev; 1142 struct dm_dev *origin_dev; 1143 1144 dm_block_t nr_blocks; 1145 uint32_t sectors_per_block; 1146 int sectors_per_block_shift; 1147 struct era_metadata *md; 1148 1149 struct workqueue_struct *wq; 1150 struct work_struct worker; 1151 1152 spinlock_t deferred_lock; 1153 struct bio_list deferred_bios; 1154 1155 spinlock_t rpc_lock; 1156 struct list_head rpc_calls; 1157 1158 struct digest digest; 1159 atomic_t suspended; 1160 }; 1161 1162 struct rpc { 1163 struct list_head list; 1164 1165 int (*fn0)(struct era_metadata *); 1166 int (*fn1)(struct era_metadata *, void *); 1167 void *arg; 1168 int result; 1169 1170 struct completion complete; 1171 }; 1172 1173 /*---------------------------------------------------------------- 1174 * Remapping. 1175 *---------------------------------------------------------------*/ 1176 static bool block_size_is_power_of_two(struct era *era) 1177 { 1178 return era->sectors_per_block_shift >= 0; 1179 } 1180 1181 static dm_block_t get_block(struct era *era, struct bio *bio) 1182 { 1183 sector_t block_nr = bio->bi_iter.bi_sector; 1184 1185 if (!block_size_is_power_of_two(era)) 1186 (void) sector_div(block_nr, era->sectors_per_block); 1187 else 1188 block_nr >>= era->sectors_per_block_shift; 1189 1190 return block_nr; 1191 } 1192 1193 static void remap_to_origin(struct era *era, struct bio *bio) 1194 { 1195 bio_set_dev(bio, era->origin_dev->bdev); 1196 } 1197 1198 /*---------------------------------------------------------------- 1199 * Worker thread 1200 *--------------------------------------------------------------*/ 1201 static void wake_worker(struct era *era) 1202 { 1203 if (!atomic_read(&era->suspended)) 1204 queue_work(era->wq, &era->worker); 1205 } 1206 1207 static void process_old_eras(struct era *era) 1208 { 1209 int r; 1210 1211 if (!era->digest.step) 1212 return; 1213 1214 r = era->digest.step(era->md, &era->digest); 1215 if (r < 0) { 1216 DMERR("%s: digest step failed, stopping digestion", __func__); 1217 era->digest.step = NULL; 1218 1219 } else if (era->digest.step) 1220 wake_worker(era); 1221 } 1222 1223 static void process_deferred_bios(struct era *era) 1224 { 1225 int r; 1226 struct bio_list deferred_bios, marked_bios; 1227 struct bio *bio; 1228 bool commit_needed = false; 1229 bool failed = false; 1230 1231 bio_list_init(&deferred_bios); 1232 bio_list_init(&marked_bios); 1233 1234 spin_lock(&era->deferred_lock); 1235 bio_list_merge(&deferred_bios, &era->deferred_bios); 1236 bio_list_init(&era->deferred_bios); 1237 spin_unlock(&era->deferred_lock); 1238 1239 while ((bio = bio_list_pop(&deferred_bios))) { 1240 r = writeset_test_and_set(&era->md->bitset_info, 1241 era->md->current_writeset, 1242 get_block(era, bio)); 1243 if (r < 0) { 1244 /* 1245 * This is bad news, we need to rollback. 1246 * FIXME: finish. 1247 */ 1248 failed = true; 1249 1250 } else if (r == 0) 1251 commit_needed = true; 1252 1253 bio_list_add(&marked_bios, bio); 1254 } 1255 1256 if (commit_needed) { 1257 r = metadata_commit(era->md); 1258 if (r) 1259 failed = true; 1260 } 1261 1262 if (failed) 1263 while ((bio = bio_list_pop(&marked_bios))) 1264 bio_io_error(bio); 1265 else 1266 while ((bio = bio_list_pop(&marked_bios))) 1267 generic_make_request(bio); 1268 } 1269 1270 static void process_rpc_calls(struct era *era) 1271 { 1272 int r; 1273 bool need_commit = false; 1274 struct list_head calls; 1275 struct rpc *rpc, *tmp; 1276 1277 INIT_LIST_HEAD(&calls); 1278 spin_lock(&era->rpc_lock); 1279 list_splice_init(&era->rpc_calls, &calls); 1280 spin_unlock(&era->rpc_lock); 1281 1282 list_for_each_entry_safe(rpc, tmp, &calls, list) { 1283 rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg); 1284 need_commit = true; 1285 } 1286 1287 if (need_commit) { 1288 r = metadata_commit(era->md); 1289 if (r) 1290 list_for_each_entry_safe(rpc, tmp, &calls, list) 1291 rpc->result = r; 1292 } 1293 1294 list_for_each_entry_safe(rpc, tmp, &calls, list) 1295 complete(&rpc->complete); 1296 } 1297 1298 static void kick_off_digest(struct era *era) 1299 { 1300 if (era->md->archived_writesets) { 1301 era->md->archived_writesets = false; 1302 metadata_digest_start(era->md, &era->digest); 1303 } 1304 } 1305 1306 static void do_work(struct work_struct *ws) 1307 { 1308 struct era *era = container_of(ws, struct era, worker); 1309 1310 kick_off_digest(era); 1311 process_old_eras(era); 1312 process_deferred_bios(era); 1313 process_rpc_calls(era); 1314 } 1315 1316 static void defer_bio(struct era *era, struct bio *bio) 1317 { 1318 spin_lock(&era->deferred_lock); 1319 bio_list_add(&era->deferred_bios, bio); 1320 spin_unlock(&era->deferred_lock); 1321 1322 wake_worker(era); 1323 } 1324 1325 /* 1326 * Make an rpc call to the worker to change the metadata. 1327 */ 1328 static int perform_rpc(struct era *era, struct rpc *rpc) 1329 { 1330 rpc->result = 0; 1331 init_completion(&rpc->complete); 1332 1333 spin_lock(&era->rpc_lock); 1334 list_add(&rpc->list, &era->rpc_calls); 1335 spin_unlock(&era->rpc_lock); 1336 1337 wake_worker(era); 1338 wait_for_completion(&rpc->complete); 1339 1340 return rpc->result; 1341 } 1342 1343 static int in_worker0(struct era *era, int (*fn)(struct era_metadata *)) 1344 { 1345 struct rpc rpc; 1346 rpc.fn0 = fn; 1347 rpc.fn1 = NULL; 1348 1349 return perform_rpc(era, &rpc); 1350 } 1351 1352 static int in_worker1(struct era *era, 1353 int (*fn)(struct era_metadata *, void *), void *arg) 1354 { 1355 struct rpc rpc; 1356 rpc.fn0 = NULL; 1357 rpc.fn1 = fn; 1358 rpc.arg = arg; 1359 1360 return perform_rpc(era, &rpc); 1361 } 1362 1363 static void start_worker(struct era *era) 1364 { 1365 atomic_set(&era->suspended, 0); 1366 } 1367 1368 static void stop_worker(struct era *era) 1369 { 1370 atomic_set(&era->suspended, 1); 1371 flush_workqueue(era->wq); 1372 } 1373 1374 /*---------------------------------------------------------------- 1375 * Target methods 1376 *--------------------------------------------------------------*/ 1377 static int dev_is_congested(struct dm_dev *dev, int bdi_bits) 1378 { 1379 struct request_queue *q = bdev_get_queue(dev->bdev); 1380 return bdi_congested(q->backing_dev_info, bdi_bits); 1381 } 1382 1383 static int era_is_congested(struct dm_target_callbacks *cb, int bdi_bits) 1384 { 1385 struct era *era = container_of(cb, struct era, callbacks); 1386 return dev_is_congested(era->origin_dev, bdi_bits); 1387 } 1388 1389 static void era_destroy(struct era *era) 1390 { 1391 if (era->md) 1392 metadata_close(era->md); 1393 1394 if (era->wq) 1395 destroy_workqueue(era->wq); 1396 1397 if (era->origin_dev) 1398 dm_put_device(era->ti, era->origin_dev); 1399 1400 if (era->metadata_dev) 1401 dm_put_device(era->ti, era->metadata_dev); 1402 1403 kfree(era); 1404 } 1405 1406 static dm_block_t calc_nr_blocks(struct era *era) 1407 { 1408 return dm_sector_div_up(era->ti->len, era->sectors_per_block); 1409 } 1410 1411 static bool valid_block_size(dm_block_t block_size) 1412 { 1413 bool greater_than_zero = block_size > 0; 1414 bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0; 1415 1416 return greater_than_zero && multiple_of_min_block_size; 1417 } 1418 1419 /* 1420 * <metadata dev> <data dev> <data block size (sectors)> 1421 */ 1422 static int era_ctr(struct dm_target *ti, unsigned argc, char **argv) 1423 { 1424 int r; 1425 char dummy; 1426 struct era *era; 1427 struct era_metadata *md; 1428 1429 if (argc != 3) { 1430 ti->error = "Invalid argument count"; 1431 return -EINVAL; 1432 } 1433 1434 era = kzalloc(sizeof(*era), GFP_KERNEL); 1435 if (!era) { 1436 ti->error = "Error allocating era structure"; 1437 return -ENOMEM; 1438 } 1439 1440 era->ti = ti; 1441 1442 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &era->metadata_dev); 1443 if (r) { 1444 ti->error = "Error opening metadata device"; 1445 era_destroy(era); 1446 return -EINVAL; 1447 } 1448 1449 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &era->origin_dev); 1450 if (r) { 1451 ti->error = "Error opening data device"; 1452 era_destroy(era); 1453 return -EINVAL; 1454 } 1455 1456 r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy); 1457 if (r != 1) { 1458 ti->error = "Error parsing block size"; 1459 era_destroy(era); 1460 return -EINVAL; 1461 } 1462 1463 r = dm_set_target_max_io_len(ti, era->sectors_per_block); 1464 if (r) { 1465 ti->error = "could not set max io len"; 1466 era_destroy(era); 1467 return -EINVAL; 1468 } 1469 1470 if (!valid_block_size(era->sectors_per_block)) { 1471 ti->error = "Invalid block size"; 1472 era_destroy(era); 1473 return -EINVAL; 1474 } 1475 if (era->sectors_per_block & (era->sectors_per_block - 1)) 1476 era->sectors_per_block_shift = -1; 1477 else 1478 era->sectors_per_block_shift = __ffs(era->sectors_per_block); 1479 1480 md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true); 1481 if (IS_ERR(md)) { 1482 ti->error = "Error reading metadata"; 1483 era_destroy(era); 1484 return PTR_ERR(md); 1485 } 1486 era->md = md; 1487 1488 era->nr_blocks = calc_nr_blocks(era); 1489 1490 r = metadata_resize(era->md, &era->nr_blocks); 1491 if (r) { 1492 ti->error = "couldn't resize metadata"; 1493 era_destroy(era); 1494 return -ENOMEM; 1495 } 1496 1497 era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); 1498 if (!era->wq) { 1499 ti->error = "could not create workqueue for metadata object"; 1500 era_destroy(era); 1501 return -ENOMEM; 1502 } 1503 INIT_WORK(&era->worker, do_work); 1504 1505 spin_lock_init(&era->deferred_lock); 1506 bio_list_init(&era->deferred_bios); 1507 1508 spin_lock_init(&era->rpc_lock); 1509 INIT_LIST_HEAD(&era->rpc_calls); 1510 1511 ti->private = era; 1512 ti->num_flush_bios = 1; 1513 ti->flush_supported = true; 1514 1515 ti->num_discard_bios = 1; 1516 era->callbacks.congested_fn = era_is_congested; 1517 dm_table_add_target_callbacks(ti->table, &era->callbacks); 1518 1519 return 0; 1520 } 1521 1522 static void era_dtr(struct dm_target *ti) 1523 { 1524 era_destroy(ti->private); 1525 } 1526 1527 static int era_map(struct dm_target *ti, struct bio *bio) 1528 { 1529 struct era *era = ti->private; 1530 dm_block_t block = get_block(era, bio); 1531 1532 /* 1533 * All bios get remapped to the origin device. We do this now, but 1534 * it may not get issued until later. Depending on whether the 1535 * block is marked in this era. 1536 */ 1537 remap_to_origin(era, bio); 1538 1539 /* 1540 * REQ_PREFLUSH bios carry no data, so we're not interested in them. 1541 */ 1542 if (!(bio->bi_opf & REQ_PREFLUSH) && 1543 (bio_data_dir(bio) == WRITE) && 1544 !metadata_current_marked(era->md, block)) { 1545 defer_bio(era, bio); 1546 return DM_MAPIO_SUBMITTED; 1547 } 1548 1549 return DM_MAPIO_REMAPPED; 1550 } 1551 1552 static void era_postsuspend(struct dm_target *ti) 1553 { 1554 int r; 1555 struct era *era = ti->private; 1556 1557 r = in_worker0(era, metadata_era_archive); 1558 if (r) { 1559 DMERR("%s: couldn't archive current era", __func__); 1560 /* FIXME: fail mode */ 1561 } 1562 1563 stop_worker(era); 1564 } 1565 1566 static int era_preresume(struct dm_target *ti) 1567 { 1568 int r; 1569 struct era *era = ti->private; 1570 dm_block_t new_size = calc_nr_blocks(era); 1571 1572 if (era->nr_blocks != new_size) { 1573 r = in_worker1(era, metadata_resize, &new_size); 1574 if (r) 1575 return r; 1576 1577 era->nr_blocks = new_size; 1578 } 1579 1580 start_worker(era); 1581 1582 r = in_worker0(era, metadata_new_era); 1583 if (r) { 1584 DMERR("%s: metadata_era_rollover failed", __func__); 1585 return r; 1586 } 1587 1588 return 0; 1589 } 1590 1591 /* 1592 * Status format: 1593 * 1594 * <metadata block size> <#used metadata blocks>/<#total metadata blocks> 1595 * <current era> <held metadata root | '-'> 1596 */ 1597 static void era_status(struct dm_target *ti, status_type_t type, 1598 unsigned status_flags, char *result, unsigned maxlen) 1599 { 1600 int r; 1601 struct era *era = ti->private; 1602 ssize_t sz = 0; 1603 struct metadata_stats stats; 1604 char buf[BDEVNAME_SIZE]; 1605 1606 switch (type) { 1607 case STATUSTYPE_INFO: 1608 r = in_worker1(era, metadata_get_stats, &stats); 1609 if (r) 1610 goto err; 1611 1612 DMEMIT("%u %llu/%llu %u", 1613 (unsigned) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT), 1614 (unsigned long long) stats.used, 1615 (unsigned long long) stats.total, 1616 (unsigned) stats.era); 1617 1618 if (stats.snap != SUPERBLOCK_LOCATION) 1619 DMEMIT(" %llu", stats.snap); 1620 else 1621 DMEMIT(" -"); 1622 break; 1623 1624 case STATUSTYPE_TABLE: 1625 format_dev_t(buf, era->metadata_dev->bdev->bd_dev); 1626 DMEMIT("%s ", buf); 1627 format_dev_t(buf, era->origin_dev->bdev->bd_dev); 1628 DMEMIT("%s %u", buf, era->sectors_per_block); 1629 break; 1630 } 1631 1632 return; 1633 1634 err: 1635 DMEMIT("Error"); 1636 } 1637 1638 static int era_message(struct dm_target *ti, unsigned argc, char **argv) 1639 { 1640 struct era *era = ti->private; 1641 1642 if (argc != 1) { 1643 DMERR("incorrect number of message arguments"); 1644 return -EINVAL; 1645 } 1646 1647 if (!strcasecmp(argv[0], "checkpoint")) 1648 return in_worker0(era, metadata_checkpoint); 1649 1650 if (!strcasecmp(argv[0], "take_metadata_snap")) 1651 return in_worker0(era, metadata_take_snap); 1652 1653 if (!strcasecmp(argv[0], "drop_metadata_snap")) 1654 return in_worker0(era, metadata_drop_snap); 1655 1656 DMERR("unsupported message '%s'", argv[0]); 1657 return -EINVAL; 1658 } 1659 1660 static sector_t get_dev_size(struct dm_dev *dev) 1661 { 1662 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT; 1663 } 1664 1665 static int era_iterate_devices(struct dm_target *ti, 1666 iterate_devices_callout_fn fn, void *data) 1667 { 1668 struct era *era = ti->private; 1669 return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data); 1670 } 1671 1672 static void era_io_hints(struct dm_target *ti, struct queue_limits *limits) 1673 { 1674 struct era *era = ti->private; 1675 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; 1676 1677 /* 1678 * If the system-determined stacked limits are compatible with the 1679 * era device's blocksize (io_opt is a factor) do not override them. 1680 */ 1681 if (io_opt_sectors < era->sectors_per_block || 1682 do_div(io_opt_sectors, era->sectors_per_block)) { 1683 blk_limits_io_min(limits, 0); 1684 blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT); 1685 } 1686 } 1687 1688 /*----------------------------------------------------------------*/ 1689 1690 static struct target_type era_target = { 1691 .name = "era", 1692 .version = {1, 0, 0}, 1693 .module = THIS_MODULE, 1694 .ctr = era_ctr, 1695 .dtr = era_dtr, 1696 .map = era_map, 1697 .postsuspend = era_postsuspend, 1698 .preresume = era_preresume, 1699 .status = era_status, 1700 .message = era_message, 1701 .iterate_devices = era_iterate_devices, 1702 .io_hints = era_io_hints 1703 }; 1704 1705 static int __init dm_era_init(void) 1706 { 1707 int r; 1708 1709 r = dm_register_target(&era_target); 1710 if (r) { 1711 DMERR("era target registration failed: %d", r); 1712 return r; 1713 } 1714 1715 return 0; 1716 } 1717 1718 static void __exit dm_era_exit(void) 1719 { 1720 dm_unregister_target(&era_target); 1721 } 1722 1723 module_init(dm_era_init); 1724 module_exit(dm_era_exit); 1725 1726 MODULE_DESCRIPTION(DM_NAME " era target"); 1727 MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); 1728 MODULE_LICENSE("GPL"); 1729