1 /* 2 * Copyright (C) 2011 Red Hat, Inc. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #include "dm-space-map-common.h" 8 #include "dm-transaction-manager.h" 9 10 #include <linux/bitops.h> 11 #include <linux/device-mapper.h> 12 13 #define DM_MSG_PREFIX "space map common" 14 15 /*----------------------------------------------------------------*/ 16 17 /* 18 * Index validator. 19 */ 20 #define INDEX_CSUM_XOR 160478 21 22 static void index_prepare_for_write(struct dm_block_validator *v, 23 struct dm_block *b, 24 size_t block_size) 25 { 26 struct disk_metadata_index *mi_le = dm_block_data(b); 27 28 mi_le->blocknr = cpu_to_le64(dm_block_location(b)); 29 mi_le->csum = cpu_to_le32(dm_bm_checksum(&mi_le->padding, 30 block_size - sizeof(__le32), 31 INDEX_CSUM_XOR)); 32 } 33 34 static int index_check(struct dm_block_validator *v, 35 struct dm_block *b, 36 size_t block_size) 37 { 38 struct disk_metadata_index *mi_le = dm_block_data(b); 39 __le32 csum_disk; 40 41 if (dm_block_location(b) != le64_to_cpu(mi_le->blocknr)) { 42 DMERR_LIMIT("index_check failed: blocknr %llu != wanted %llu", 43 le64_to_cpu(mi_le->blocknr), dm_block_location(b)); 44 return -ENOTBLK; 45 } 46 47 csum_disk = cpu_to_le32(dm_bm_checksum(&mi_le->padding, 48 block_size - sizeof(__le32), 49 INDEX_CSUM_XOR)); 50 if (csum_disk != mi_le->csum) { 51 DMERR_LIMIT("index_check failed: csum %u != wanted %u", 52 le32_to_cpu(csum_disk), le32_to_cpu(mi_le->csum)); 53 return -EILSEQ; 54 } 55 56 return 0; 57 } 58 59 static struct dm_block_validator index_validator = { 60 .name = "index", 61 .prepare_for_write = index_prepare_for_write, 62 .check = index_check 63 }; 64 65 /*----------------------------------------------------------------*/ 66 67 /* 68 * Bitmap validator 69 */ 70 #define BITMAP_CSUM_XOR 240779 71 72 static void bitmap_prepare_for_write(struct dm_block_validator *v, 73 struct dm_block *b, 74 size_t block_size) 75 { 76 struct disk_bitmap_header *disk_header = dm_block_data(b); 77 78 disk_header->blocknr = cpu_to_le64(dm_block_location(b)); 79 disk_header->csum = cpu_to_le32(dm_bm_checksum(&disk_header->not_used, 80 block_size - sizeof(__le32), 81 BITMAP_CSUM_XOR)); 82 } 83 84 static int bitmap_check(struct dm_block_validator *v, 85 struct dm_block *b, 86 size_t block_size) 87 { 88 struct disk_bitmap_header *disk_header = dm_block_data(b); 89 __le32 csum_disk; 90 91 if (dm_block_location(b) != le64_to_cpu(disk_header->blocknr)) { 92 DMERR_LIMIT("bitmap check failed: blocknr %llu != wanted %llu", 93 le64_to_cpu(disk_header->blocknr), dm_block_location(b)); 94 return -ENOTBLK; 95 } 96 97 csum_disk = cpu_to_le32(dm_bm_checksum(&disk_header->not_used, 98 block_size - sizeof(__le32), 99 BITMAP_CSUM_XOR)); 100 if (csum_disk != disk_header->csum) { 101 DMERR_LIMIT("bitmap check failed: csum %u != wanted %u", 102 le32_to_cpu(csum_disk), le32_to_cpu(disk_header->csum)); 103 return -EILSEQ; 104 } 105 106 return 0; 107 } 108 109 static struct dm_block_validator dm_sm_bitmap_validator = { 110 .name = "sm_bitmap", 111 .prepare_for_write = bitmap_prepare_for_write, 112 .check = bitmap_check 113 }; 114 115 /*----------------------------------------------------------------*/ 116 117 #define ENTRIES_PER_WORD 32 118 #define ENTRIES_SHIFT 5 119 120 static void *dm_bitmap_data(struct dm_block *b) 121 { 122 return dm_block_data(b) + sizeof(struct disk_bitmap_header); 123 } 124 125 #define WORD_MASK_HIGH 0xAAAAAAAAAAAAAAAAULL 126 127 static unsigned bitmap_word_used(void *addr, unsigned b) 128 { 129 __le64 *words_le = addr; 130 __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); 131 132 uint64_t bits = le64_to_cpu(*w_le); 133 uint64_t mask = (bits + WORD_MASK_HIGH + 1) & WORD_MASK_HIGH; 134 135 return !(~bits & mask); 136 } 137 138 static unsigned sm_lookup_bitmap(void *addr, unsigned b) 139 { 140 __le64 *words_le = addr; 141 __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); 142 unsigned hi, lo; 143 144 b = (b & (ENTRIES_PER_WORD - 1)) << 1; 145 hi = !!test_bit_le(b, (void *) w_le); 146 lo = !!test_bit_le(b + 1, (void *) w_le); 147 return (hi << 1) | lo; 148 } 149 150 static void sm_set_bitmap(void *addr, unsigned b, unsigned val) 151 { 152 __le64 *words_le = addr; 153 __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); 154 155 b = (b & (ENTRIES_PER_WORD - 1)) << 1; 156 157 if (val & 2) 158 __set_bit_le(b, (void *) w_le); 159 else 160 __clear_bit_le(b, (void *) w_le); 161 162 if (val & 1) 163 __set_bit_le(b + 1, (void *) w_le); 164 else 165 __clear_bit_le(b + 1, (void *) w_le); 166 } 167 168 static int sm_find_free(void *addr, unsigned begin, unsigned end, 169 unsigned *result) 170 { 171 while (begin < end) { 172 if (!(begin & (ENTRIES_PER_WORD - 1)) && 173 bitmap_word_used(addr, begin)) { 174 begin += ENTRIES_PER_WORD; 175 continue; 176 } 177 178 if (!sm_lookup_bitmap(addr, begin)) { 179 *result = begin; 180 return 0; 181 } 182 183 begin++; 184 } 185 186 return -ENOSPC; 187 } 188 189 /*----------------------------------------------------------------*/ 190 191 static int sm_ll_init(struct ll_disk *ll, struct dm_transaction_manager *tm) 192 { 193 ll->tm = tm; 194 195 ll->bitmap_info.tm = tm; 196 ll->bitmap_info.levels = 1; 197 198 /* 199 * Because the new bitmap blocks are created via a shadow 200 * operation, the old entry has already had its reference count 201 * decremented and we don't need the btree to do any bookkeeping. 202 */ 203 ll->bitmap_info.value_type.size = sizeof(struct disk_index_entry); 204 ll->bitmap_info.value_type.inc = NULL; 205 ll->bitmap_info.value_type.dec = NULL; 206 ll->bitmap_info.value_type.equal = NULL; 207 208 ll->ref_count_info.tm = tm; 209 ll->ref_count_info.levels = 1; 210 ll->ref_count_info.value_type.size = sizeof(uint32_t); 211 ll->ref_count_info.value_type.inc = NULL; 212 ll->ref_count_info.value_type.dec = NULL; 213 ll->ref_count_info.value_type.equal = NULL; 214 215 ll->block_size = dm_bm_block_size(dm_tm_get_bm(tm)); 216 217 if (ll->block_size > (1 << 30)) { 218 DMERR("block size too big to hold bitmaps"); 219 return -EINVAL; 220 } 221 222 ll->entries_per_block = (ll->block_size - sizeof(struct disk_bitmap_header)) * 223 ENTRIES_PER_BYTE; 224 ll->nr_blocks = 0; 225 ll->bitmap_root = 0; 226 ll->ref_count_root = 0; 227 ll->bitmap_index_changed = false; 228 229 return 0; 230 } 231 232 int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks) 233 { 234 int r; 235 dm_block_t i, nr_blocks, nr_indexes; 236 unsigned old_blocks, blocks; 237 238 nr_blocks = ll->nr_blocks + extra_blocks; 239 old_blocks = dm_sector_div_up(ll->nr_blocks, ll->entries_per_block); 240 blocks = dm_sector_div_up(nr_blocks, ll->entries_per_block); 241 242 nr_indexes = dm_sector_div_up(nr_blocks, ll->entries_per_block); 243 if (nr_indexes > ll->max_entries(ll)) { 244 DMERR("space map too large"); 245 return -EINVAL; 246 } 247 248 for (i = old_blocks; i < blocks; i++) { 249 struct dm_block *b; 250 struct disk_index_entry idx; 251 252 r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b); 253 if (r < 0) 254 return r; 255 idx.blocknr = cpu_to_le64(dm_block_location(b)); 256 257 r = dm_tm_unlock(ll->tm, b); 258 if (r < 0) 259 return r; 260 261 idx.nr_free = cpu_to_le32(ll->entries_per_block); 262 idx.none_free_before = 0; 263 264 r = ll->save_ie(ll, i, &idx); 265 if (r < 0) 266 return r; 267 } 268 269 ll->nr_blocks = nr_blocks; 270 return 0; 271 } 272 273 int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result) 274 { 275 int r; 276 dm_block_t index = b; 277 struct disk_index_entry ie_disk; 278 struct dm_block *blk; 279 280 b = do_div(index, ll->entries_per_block); 281 r = ll->load_ie(ll, index, &ie_disk); 282 if (r < 0) 283 return r; 284 285 r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr), 286 &dm_sm_bitmap_validator, &blk); 287 if (r < 0) 288 return r; 289 290 *result = sm_lookup_bitmap(dm_bitmap_data(blk), b); 291 292 return dm_tm_unlock(ll->tm, blk); 293 } 294 295 static int sm_ll_lookup_big_ref_count(struct ll_disk *ll, dm_block_t b, 296 uint32_t *result) 297 { 298 __le32 le_rc; 299 int r; 300 301 r = dm_btree_lookup(&ll->ref_count_info, ll->ref_count_root, &b, &le_rc); 302 if (r < 0) 303 return r; 304 305 *result = le32_to_cpu(le_rc); 306 307 return r; 308 } 309 310 int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result) 311 { 312 int r = sm_ll_lookup_bitmap(ll, b, result); 313 314 if (r) 315 return r; 316 317 if (*result != 3) 318 return r; 319 320 return sm_ll_lookup_big_ref_count(ll, b, result); 321 } 322 323 int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin, 324 dm_block_t end, dm_block_t *result) 325 { 326 int r; 327 struct disk_index_entry ie_disk; 328 dm_block_t i, index_begin = begin; 329 dm_block_t index_end = dm_sector_div_up(end, ll->entries_per_block); 330 331 /* 332 * FIXME: Use shifts 333 */ 334 begin = do_div(index_begin, ll->entries_per_block); 335 end = do_div(end, ll->entries_per_block); 336 337 for (i = index_begin; i < index_end; i++, begin = 0) { 338 struct dm_block *blk; 339 unsigned position; 340 uint32_t bit_end; 341 342 r = ll->load_ie(ll, i, &ie_disk); 343 if (r < 0) 344 return r; 345 346 if (le32_to_cpu(ie_disk.nr_free) == 0) 347 continue; 348 349 r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr), 350 &dm_sm_bitmap_validator, &blk); 351 if (r < 0) 352 return r; 353 354 bit_end = (i == index_end - 1) ? end : ll->entries_per_block; 355 356 r = sm_find_free(dm_bitmap_data(blk), 357 max_t(unsigned, begin, le32_to_cpu(ie_disk.none_free_before)), 358 bit_end, &position); 359 if (r == -ENOSPC) { 360 /* 361 * This might happen because we started searching 362 * part way through the bitmap. 363 */ 364 dm_tm_unlock(ll->tm, blk); 365 continue; 366 367 } else if (r < 0) { 368 dm_tm_unlock(ll->tm, blk); 369 return r; 370 } 371 372 r = dm_tm_unlock(ll->tm, blk); 373 if (r < 0) 374 return r; 375 376 *result = i * ll->entries_per_block + (dm_block_t) position; 377 return 0; 378 } 379 380 return -ENOSPC; 381 } 382 383 static int sm_ll_mutate(struct ll_disk *ll, dm_block_t b, 384 uint32_t (*mutator)(void *context, uint32_t old), 385 void *context, enum allocation_event *ev) 386 { 387 int r; 388 uint32_t bit, old, ref_count; 389 struct dm_block *nb; 390 dm_block_t index = b; 391 struct disk_index_entry ie_disk; 392 void *bm_le; 393 int inc; 394 395 bit = do_div(index, ll->entries_per_block); 396 r = ll->load_ie(ll, index, &ie_disk); 397 if (r < 0) 398 return r; 399 400 r = dm_tm_shadow_block(ll->tm, le64_to_cpu(ie_disk.blocknr), 401 &dm_sm_bitmap_validator, &nb, &inc); 402 if (r < 0) { 403 DMERR("dm_tm_shadow_block() failed"); 404 return r; 405 } 406 ie_disk.blocknr = cpu_to_le64(dm_block_location(nb)); 407 408 bm_le = dm_bitmap_data(nb); 409 old = sm_lookup_bitmap(bm_le, bit); 410 411 if (old > 2) { 412 r = sm_ll_lookup_big_ref_count(ll, b, &old); 413 if (r < 0) 414 return r; 415 } 416 417 ref_count = mutator(context, old); 418 419 if (ref_count <= 2) { 420 sm_set_bitmap(bm_le, bit, ref_count); 421 422 r = dm_tm_unlock(ll->tm, nb); 423 if (r < 0) 424 return r; 425 426 if (old > 2) { 427 r = dm_btree_remove(&ll->ref_count_info, 428 ll->ref_count_root, 429 &b, &ll->ref_count_root); 430 if (r) 431 return r; 432 } 433 434 } else { 435 __le32 le_rc = cpu_to_le32(ref_count); 436 437 sm_set_bitmap(bm_le, bit, 3); 438 r = dm_tm_unlock(ll->tm, nb); 439 if (r < 0) 440 return r; 441 442 __dm_bless_for_disk(&le_rc); 443 r = dm_btree_insert(&ll->ref_count_info, ll->ref_count_root, 444 &b, &le_rc, &ll->ref_count_root); 445 if (r < 0) { 446 DMERR("ref count insert failed"); 447 return r; 448 } 449 } 450 451 if (ref_count && !old) { 452 *ev = SM_ALLOC; 453 ll->nr_allocated++; 454 le32_add_cpu(&ie_disk.nr_free, -1); 455 if (le32_to_cpu(ie_disk.none_free_before) == bit) 456 ie_disk.none_free_before = cpu_to_le32(bit + 1); 457 458 } else if (old && !ref_count) { 459 *ev = SM_FREE; 460 ll->nr_allocated--; 461 le32_add_cpu(&ie_disk.nr_free, 1); 462 ie_disk.none_free_before = cpu_to_le32(min(le32_to_cpu(ie_disk.none_free_before), bit)); 463 } 464 465 return ll->save_ie(ll, index, &ie_disk); 466 } 467 468 static uint32_t set_ref_count(void *context, uint32_t old) 469 { 470 return *((uint32_t *) context); 471 } 472 473 int sm_ll_insert(struct ll_disk *ll, dm_block_t b, 474 uint32_t ref_count, enum allocation_event *ev) 475 { 476 return sm_ll_mutate(ll, b, set_ref_count, &ref_count, ev); 477 } 478 479 static uint32_t inc_ref_count(void *context, uint32_t old) 480 { 481 return old + 1; 482 } 483 484 int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) 485 { 486 return sm_ll_mutate(ll, b, inc_ref_count, NULL, ev); 487 } 488 489 static uint32_t dec_ref_count(void *context, uint32_t old) 490 { 491 return old - 1; 492 } 493 494 int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) 495 { 496 return sm_ll_mutate(ll, b, dec_ref_count, NULL, ev); 497 } 498 499 int sm_ll_commit(struct ll_disk *ll) 500 { 501 int r = 0; 502 503 if (ll->bitmap_index_changed) { 504 r = ll->commit(ll); 505 if (!r) 506 ll->bitmap_index_changed = false; 507 } 508 509 return r; 510 } 511 512 /*----------------------------------------------------------------*/ 513 514 static int metadata_ll_load_ie(struct ll_disk *ll, dm_block_t index, 515 struct disk_index_entry *ie) 516 { 517 memcpy(ie, ll->mi_le.index + index, sizeof(*ie)); 518 return 0; 519 } 520 521 static int metadata_ll_save_ie(struct ll_disk *ll, dm_block_t index, 522 struct disk_index_entry *ie) 523 { 524 ll->bitmap_index_changed = true; 525 memcpy(ll->mi_le.index + index, ie, sizeof(*ie)); 526 return 0; 527 } 528 529 static int metadata_ll_init_index(struct ll_disk *ll) 530 { 531 int r; 532 struct dm_block *b; 533 534 r = dm_tm_new_block(ll->tm, &index_validator, &b); 535 if (r < 0) 536 return r; 537 538 memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le)); 539 ll->bitmap_root = dm_block_location(b); 540 541 return dm_tm_unlock(ll->tm, b); 542 } 543 544 static int metadata_ll_open(struct ll_disk *ll) 545 { 546 int r; 547 struct dm_block *block; 548 549 r = dm_tm_read_lock(ll->tm, ll->bitmap_root, 550 &index_validator, &block); 551 if (r) 552 return r; 553 554 memcpy(&ll->mi_le, dm_block_data(block), sizeof(ll->mi_le)); 555 return dm_tm_unlock(ll->tm, block); 556 } 557 558 static dm_block_t metadata_ll_max_entries(struct ll_disk *ll) 559 { 560 return MAX_METADATA_BITMAPS; 561 } 562 563 static int metadata_ll_commit(struct ll_disk *ll) 564 { 565 int r, inc; 566 struct dm_block *b; 567 568 r = dm_tm_shadow_block(ll->tm, ll->bitmap_root, &index_validator, &b, &inc); 569 if (r) 570 return r; 571 572 memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le)); 573 ll->bitmap_root = dm_block_location(b); 574 575 return dm_tm_unlock(ll->tm, b); 576 } 577 578 int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm) 579 { 580 int r; 581 582 r = sm_ll_init(ll, tm); 583 if (r < 0) 584 return r; 585 586 ll->load_ie = metadata_ll_load_ie; 587 ll->save_ie = metadata_ll_save_ie; 588 ll->init_index = metadata_ll_init_index; 589 ll->open_index = metadata_ll_open; 590 ll->max_entries = metadata_ll_max_entries; 591 ll->commit = metadata_ll_commit; 592 593 ll->nr_blocks = 0; 594 ll->nr_allocated = 0; 595 596 r = ll->init_index(ll); 597 if (r < 0) 598 return r; 599 600 r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root); 601 if (r < 0) 602 return r; 603 604 return 0; 605 } 606 607 int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm, 608 void *root_le, size_t len) 609 { 610 int r; 611 struct disk_sm_root *smr = root_le; 612 613 if (len < sizeof(struct disk_sm_root)) { 614 DMERR("sm_metadata root too small"); 615 return -ENOMEM; 616 } 617 618 r = sm_ll_init(ll, tm); 619 if (r < 0) 620 return r; 621 622 ll->load_ie = metadata_ll_load_ie; 623 ll->save_ie = metadata_ll_save_ie; 624 ll->init_index = metadata_ll_init_index; 625 ll->open_index = metadata_ll_open; 626 ll->max_entries = metadata_ll_max_entries; 627 ll->commit = metadata_ll_commit; 628 629 ll->nr_blocks = le64_to_cpu(smr->nr_blocks); 630 ll->nr_allocated = le64_to_cpu(smr->nr_allocated); 631 ll->bitmap_root = le64_to_cpu(smr->bitmap_root); 632 ll->ref_count_root = le64_to_cpu(smr->ref_count_root); 633 634 return ll->open_index(ll); 635 } 636 637 /*----------------------------------------------------------------*/ 638 639 static int disk_ll_load_ie(struct ll_disk *ll, dm_block_t index, 640 struct disk_index_entry *ie) 641 { 642 return dm_btree_lookup(&ll->bitmap_info, ll->bitmap_root, &index, ie); 643 } 644 645 static int disk_ll_save_ie(struct ll_disk *ll, dm_block_t index, 646 struct disk_index_entry *ie) 647 { 648 __dm_bless_for_disk(ie); 649 return dm_btree_insert(&ll->bitmap_info, ll->bitmap_root, 650 &index, ie, &ll->bitmap_root); 651 } 652 653 static int disk_ll_init_index(struct ll_disk *ll) 654 { 655 return dm_btree_empty(&ll->bitmap_info, &ll->bitmap_root); 656 } 657 658 static int disk_ll_open(struct ll_disk *ll) 659 { 660 /* nothing to do */ 661 return 0; 662 } 663 664 static dm_block_t disk_ll_max_entries(struct ll_disk *ll) 665 { 666 return -1ULL; 667 } 668 669 static int disk_ll_commit(struct ll_disk *ll) 670 { 671 return 0; 672 } 673 674 int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm) 675 { 676 int r; 677 678 r = sm_ll_init(ll, tm); 679 if (r < 0) 680 return r; 681 682 ll->load_ie = disk_ll_load_ie; 683 ll->save_ie = disk_ll_save_ie; 684 ll->init_index = disk_ll_init_index; 685 ll->open_index = disk_ll_open; 686 ll->max_entries = disk_ll_max_entries; 687 ll->commit = disk_ll_commit; 688 689 ll->nr_blocks = 0; 690 ll->nr_allocated = 0; 691 692 r = ll->init_index(ll); 693 if (r < 0) 694 return r; 695 696 r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root); 697 if (r < 0) 698 return r; 699 700 return 0; 701 } 702 703 int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm, 704 void *root_le, size_t len) 705 { 706 int r; 707 struct disk_sm_root *smr = root_le; 708 709 if (len < sizeof(struct disk_sm_root)) { 710 DMERR("sm_metadata root too small"); 711 return -ENOMEM; 712 } 713 714 r = sm_ll_init(ll, tm); 715 if (r < 0) 716 return r; 717 718 ll->load_ie = disk_ll_load_ie; 719 ll->save_ie = disk_ll_save_ie; 720 ll->init_index = disk_ll_init_index; 721 ll->open_index = disk_ll_open; 722 ll->max_entries = disk_ll_max_entries; 723 ll->commit = disk_ll_commit; 724 725 ll->nr_blocks = le64_to_cpu(smr->nr_blocks); 726 ll->nr_allocated = le64_to_cpu(smr->nr_allocated); 727 ll->bitmap_root = le64_to_cpu(smr->bitmap_root); 728 ll->ref_count_root = le64_to_cpu(smr->ref_count_root); 729 730 return ll->open_index(ll); 731 } 732 733 /*----------------------------------------------------------------*/ 734