1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Copyright (C) 2015 Facebook. All rights reserved. 4 */ 5 6#include <linux/kernel.h> 7#include <linux/sched/mm.h> 8#include "messages.h" 9#include "ctree.h" 10#include "disk-io.h" 11#include "locking.h" 12#include "free-space-tree.h" 13#include "transaction.h" 14#include "block-group.h" 15#include "fs.h" 16#include "accessors.h" 17#include "extent-tree.h" 18#include "root-tree.h" 19 20static int __add_block_group_free_space(struct btrfs_trans_handle *trans, 21 struct btrfs_block_group *block_group, 22 struct btrfs_path *path); 23 24static struct btrfs_root *btrfs_free_space_root( 25 struct btrfs_block_group *block_group) 26{ 27 struct btrfs_key key = { 28 .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID, 29 .type = BTRFS_ROOT_ITEM_KEY, 30 .offset = 0, 31 }; 32 33 if (btrfs_fs_incompat(block_group->fs_info, EXTENT_TREE_V2)) 34 key.offset = block_group->global_root_id; 35 return btrfs_global_root(block_group->fs_info, &key); 36} 37 38void set_free_space_tree_thresholds(struct btrfs_block_group *cache) 39{ 40 u32 bitmap_range; 41 size_t bitmap_size; 42 u64 num_bitmaps, total_bitmap_size; 43 44 if (WARN_ON(cache->length == 0)) 45 btrfs_warn(cache->fs_info, "block group %llu length is zero", 46 cache->start); 47 48 /* 49 * We convert to bitmaps when the disk space required for using extents 50 * exceeds that required for using bitmaps. 51 */ 52 bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS; 53 num_bitmaps = div_u64(cache->length + bitmap_range - 1, bitmap_range); 54 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE; 55 total_bitmap_size = num_bitmaps * bitmap_size; 56 cache->bitmap_high_thresh = div_u64(total_bitmap_size, 57 sizeof(struct btrfs_item)); 58 59 /* 60 * We allow for a small buffer between the high threshold and low 61 * threshold to avoid thrashing back and forth between the two formats. 62 */ 63 if (cache->bitmap_high_thresh > 100) 64 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100; 65 else 66 cache->bitmap_low_thresh = 0; 67} 68 69static int add_new_free_space_info(struct btrfs_trans_handle *trans, 70 struct btrfs_block_group *block_group, 71 struct btrfs_path *path) 72{ 73 struct btrfs_root *root = btrfs_free_space_root(block_group); 74 struct btrfs_free_space_info *info; 75 struct btrfs_key key; 76 struct extent_buffer *leaf; 77 int ret; 78 79 key.objectid = block_group->start; 80 key.type = BTRFS_FREE_SPACE_INFO_KEY; 81 key.offset = block_group->length; 82 83 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info)); 84 if (ret) 85 goto out; 86 87 leaf = path->nodes[0]; 88 info = btrfs_item_ptr(leaf, path->slots[0], 89 struct btrfs_free_space_info); 90 btrfs_set_free_space_extent_count(leaf, info, 0); 91 btrfs_set_free_space_flags(leaf, info, 0); 92 btrfs_mark_buffer_dirty(trans, leaf); 93 94 ret = 0; 95out: 96 btrfs_release_path(path); 97 return ret; 98} 99 100EXPORT_FOR_TESTS 101struct btrfs_free_space_info *search_free_space_info( 102 struct btrfs_trans_handle *trans, 103 struct btrfs_block_group *block_group, 104 struct btrfs_path *path, int cow) 105{ 106 struct btrfs_fs_info *fs_info = block_group->fs_info; 107 struct btrfs_root *root = btrfs_free_space_root(block_group); 108 struct btrfs_key key; 109 int ret; 110 111 key.objectid = block_group->start; 112 key.type = BTRFS_FREE_SPACE_INFO_KEY; 113 key.offset = block_group->length; 114 115 ret = btrfs_search_slot(trans, root, &key, path, 0, cow); 116 if (ret < 0) 117 return ERR_PTR(ret); 118 if (ret != 0) { 119 btrfs_warn(fs_info, "missing free space info for %llu", 120 block_group->start); 121 ASSERT(0); 122 return ERR_PTR(-ENOENT); 123 } 124 125 return btrfs_item_ptr(path->nodes[0], path->slots[0], 126 struct btrfs_free_space_info); 127} 128 129/* 130 * btrfs_search_slot() but we're looking for the greatest key less than the 131 * passed key. 132 */ 133static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans, 134 struct btrfs_root *root, 135 struct btrfs_key *key, struct btrfs_path *p, 136 int ins_len, int cow) 137{ 138 int ret; 139 140 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow); 141 if (ret < 0) 142 return ret; 143 144 if (ret == 0) { 145 ASSERT(0); 146 return -EIO; 147 } 148 149 if (p->slots[0] == 0) { 150 ASSERT(0); 151 return -EIO; 152 } 153 p->slots[0]--; 154 155 return 0; 156} 157 158static inline u32 free_space_bitmap_size(const struct btrfs_fs_info *fs_info, 159 u64 size) 160{ 161 return DIV_ROUND_UP(size >> fs_info->sectorsize_bits, BITS_PER_BYTE); 162} 163 164static unsigned long *alloc_bitmap(u32 bitmap_size) 165{ 166 unsigned long *ret; 167 unsigned int nofs_flag; 168 u32 bitmap_rounded_size = round_up(bitmap_size, sizeof(unsigned long)); 169 170 /* 171 * GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse 172 * into the filesystem as the free space bitmap can be modified in the 173 * critical section of a transaction commit. 174 * 175 * TODO: push the memalloc_nofs_{save,restore}() to the caller where we 176 * know that recursion is unsafe. 177 */ 178 nofs_flag = memalloc_nofs_save(); 179 ret = kvzalloc(bitmap_rounded_size, GFP_KERNEL); 180 memalloc_nofs_restore(nofs_flag); 181 return ret; 182} 183 184static void le_bitmap_set(unsigned long *map, unsigned int start, int len) 185{ 186 u8 *p = ((u8 *)map) + BIT_BYTE(start); 187 const unsigned int size = start + len; 188 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE); 189 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start); 190 191 while (len - bits_to_set >= 0) { 192 *p |= mask_to_set; 193 len -= bits_to_set; 194 bits_to_set = BITS_PER_BYTE; 195 mask_to_set = ~0; 196 p++; 197 } 198 if (len) { 199 mask_to_set &= BITMAP_LAST_BYTE_MASK(size); 200 *p |= mask_to_set; 201 } 202} 203 204EXPORT_FOR_TESTS 205int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans, 206 struct btrfs_block_group *block_group, 207 struct btrfs_path *path) 208{ 209 struct btrfs_fs_info *fs_info = trans->fs_info; 210 struct btrfs_root *root = btrfs_free_space_root(block_group); 211 struct btrfs_free_space_info *info; 212 struct btrfs_key key, found_key; 213 struct extent_buffer *leaf; 214 unsigned long *bitmap; 215 char *bitmap_cursor; 216 u64 start, end; 217 u64 bitmap_range, i; 218 u32 bitmap_size, flags, expected_extent_count; 219 u32 extent_count = 0; 220 int done = 0, nr; 221 int ret; 222 223 bitmap_size = free_space_bitmap_size(fs_info, block_group->length); 224 bitmap = alloc_bitmap(bitmap_size); 225 if (!bitmap) { 226 ret = -ENOMEM; 227 goto out; 228 } 229 230 start = block_group->start; 231 end = block_group->start + block_group->length; 232 233 key.objectid = end - 1; 234 key.type = (u8)-1; 235 key.offset = (u64)-1; 236 237 while (!done) { 238 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); 239 if (ret) 240 goto out; 241 242 leaf = path->nodes[0]; 243 nr = 0; 244 path->slots[0]++; 245 while (path->slots[0] > 0) { 246 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1); 247 248 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) { 249 ASSERT(found_key.objectid == block_group->start); 250 ASSERT(found_key.offset == block_group->length); 251 done = 1; 252 break; 253 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) { 254 u64 first, last; 255 256 ASSERT(found_key.objectid >= start); 257 ASSERT(found_key.objectid < end); 258 ASSERT(found_key.objectid + found_key.offset <= end); 259 260 first = div_u64(found_key.objectid - start, 261 fs_info->sectorsize); 262 last = div_u64(found_key.objectid + found_key.offset - start, 263 fs_info->sectorsize); 264 le_bitmap_set(bitmap, first, last - first); 265 266 extent_count++; 267 nr++; 268 path->slots[0]--; 269 } else { 270 ASSERT(0); 271 } 272 } 273 274 ret = btrfs_del_items(trans, root, path, path->slots[0], nr); 275 if (ret) 276 goto out; 277 btrfs_release_path(path); 278 } 279 280 info = search_free_space_info(trans, block_group, path, 1); 281 if (IS_ERR(info)) { 282 ret = PTR_ERR(info); 283 goto out; 284 } 285 leaf = path->nodes[0]; 286 flags = btrfs_free_space_flags(leaf, info); 287 flags |= BTRFS_FREE_SPACE_USING_BITMAPS; 288 btrfs_set_free_space_flags(leaf, info, flags); 289 expected_extent_count = btrfs_free_space_extent_count(leaf, info); 290 btrfs_mark_buffer_dirty(trans, leaf); 291 btrfs_release_path(path); 292 293 if (extent_count != expected_extent_count) { 294 btrfs_err(fs_info, 295 "incorrect extent count for %llu; counted %u, expected %u", 296 block_group->start, extent_count, 297 expected_extent_count); 298 ASSERT(0); 299 ret = -EIO; 300 goto out; 301 } 302 303 bitmap_cursor = (char *)bitmap; 304 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS; 305 i = start; 306 while (i < end) { 307 unsigned long ptr; 308 u64 extent_size; 309 u32 data_size; 310 311 extent_size = min(end - i, bitmap_range); 312 data_size = free_space_bitmap_size(fs_info, extent_size); 313 314 key.objectid = i; 315 key.type = BTRFS_FREE_SPACE_BITMAP_KEY; 316 key.offset = extent_size; 317 318 ret = btrfs_insert_empty_item(trans, root, path, &key, 319 data_size); 320 if (ret) 321 goto out; 322 323 leaf = path->nodes[0]; 324 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); 325 write_extent_buffer(leaf, bitmap_cursor, ptr, 326 data_size); 327 btrfs_mark_buffer_dirty(trans, leaf); 328 btrfs_release_path(path); 329 330 i += extent_size; 331 bitmap_cursor += data_size; 332 } 333 334 ret = 0; 335out: 336 kvfree(bitmap); 337 if (ret) 338 btrfs_abort_transaction(trans, ret); 339 return ret; 340} 341 342EXPORT_FOR_TESTS 343int convert_free_space_to_extents(struct btrfs_trans_handle *trans, 344 struct btrfs_block_group *block_group, 345 struct btrfs_path *path) 346{ 347 struct btrfs_fs_info *fs_info = trans->fs_info; 348 struct btrfs_root *root = btrfs_free_space_root(block_group); 349 struct btrfs_free_space_info *info; 350 struct btrfs_key key, found_key; 351 struct extent_buffer *leaf; 352 unsigned long *bitmap; 353 u64 start, end; 354 u32 bitmap_size, flags, expected_extent_count; 355 unsigned long nrbits, start_bit, end_bit; 356 u32 extent_count = 0; 357 int done = 0, nr; 358 int ret; 359 360 bitmap_size = free_space_bitmap_size(fs_info, block_group->length); 361 bitmap = alloc_bitmap(bitmap_size); 362 if (!bitmap) { 363 ret = -ENOMEM; 364 goto out; 365 } 366 367 start = block_group->start; 368 end = block_group->start + block_group->length; 369 370 key.objectid = end - 1; 371 key.type = (u8)-1; 372 key.offset = (u64)-1; 373 374 while (!done) { 375 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); 376 if (ret) 377 goto out; 378 379 leaf = path->nodes[0]; 380 nr = 0; 381 path->slots[0]++; 382 while (path->slots[0] > 0) { 383 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1); 384 385 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) { 386 ASSERT(found_key.objectid == block_group->start); 387 ASSERT(found_key.offset == block_group->length); 388 done = 1; 389 break; 390 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) { 391 unsigned long ptr; 392 char *bitmap_cursor; 393 u32 bitmap_pos, data_size; 394 395 ASSERT(found_key.objectid >= start); 396 ASSERT(found_key.objectid < end); 397 ASSERT(found_key.objectid + found_key.offset <= end); 398 399 bitmap_pos = div_u64(found_key.objectid - start, 400 fs_info->sectorsize * 401 BITS_PER_BYTE); 402 bitmap_cursor = ((char *)bitmap) + bitmap_pos; 403 data_size = free_space_bitmap_size(fs_info, 404 found_key.offset); 405 406 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1); 407 read_extent_buffer(leaf, bitmap_cursor, ptr, 408 data_size); 409 410 nr++; 411 path->slots[0]--; 412 } else { 413 ASSERT(0); 414 } 415 } 416 417 ret = btrfs_del_items(trans, root, path, path->slots[0], nr); 418 if (ret) 419 goto out; 420 btrfs_release_path(path); 421 } 422 423 info = search_free_space_info(trans, block_group, path, 1); 424 if (IS_ERR(info)) { 425 ret = PTR_ERR(info); 426 goto out; 427 } 428 leaf = path->nodes[0]; 429 flags = btrfs_free_space_flags(leaf, info); 430 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS; 431 btrfs_set_free_space_flags(leaf, info, flags); 432 expected_extent_count = btrfs_free_space_extent_count(leaf, info); 433 btrfs_mark_buffer_dirty(trans, leaf); 434 btrfs_release_path(path); 435 436 nrbits = block_group->length >> block_group->fs_info->sectorsize_bits; 437 start_bit = find_next_bit_le(bitmap, nrbits, 0); 438 439 while (start_bit < nrbits) { 440 end_bit = find_next_zero_bit_le(bitmap, nrbits, start_bit); 441 ASSERT(start_bit < end_bit); 442 443 key.objectid = start + start_bit * block_group->fs_info->sectorsize; 444 key.type = BTRFS_FREE_SPACE_EXTENT_KEY; 445 key.offset = (end_bit - start_bit) * block_group->fs_info->sectorsize; 446 447 ret = btrfs_insert_empty_item(trans, root, path, &key, 0); 448 if (ret) 449 goto out; 450 btrfs_release_path(path); 451 452 extent_count++; 453 454 start_bit = find_next_bit_le(bitmap, nrbits, end_bit); 455 } 456 457 if (extent_count != expected_extent_count) { 458 btrfs_err(fs_info, 459 "incorrect extent count for %llu; counted %u, expected %u", 460 block_group->start, extent_count, 461 expected_extent_count); 462 ASSERT(0); 463 ret = -EIO; 464 goto out; 465 } 466 467 ret = 0; 468out: 469 kvfree(bitmap); 470 if (ret) 471 btrfs_abort_transaction(trans, ret); 472 return ret; 473} 474 475static int update_free_space_extent_count(struct btrfs_trans_handle *trans, 476 struct btrfs_block_group *block_group, 477 struct btrfs_path *path, 478 int new_extents) 479{ 480 struct btrfs_free_space_info *info; 481 u32 flags; 482 u32 extent_count; 483 int ret = 0; 484 485 if (new_extents == 0) 486 return 0; 487 488 info = search_free_space_info(trans, block_group, path, 1); 489 if (IS_ERR(info)) { 490 ret = PTR_ERR(info); 491 goto out; 492 } 493 flags = btrfs_free_space_flags(path->nodes[0], info); 494 extent_count = btrfs_free_space_extent_count(path->nodes[0], info); 495 496 extent_count += new_extents; 497 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count); 498 btrfs_mark_buffer_dirty(trans, path->nodes[0]); 499 btrfs_release_path(path); 500 501 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) && 502 extent_count > block_group->bitmap_high_thresh) { 503 ret = convert_free_space_to_bitmaps(trans, block_group, path); 504 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) && 505 extent_count < block_group->bitmap_low_thresh) { 506 ret = convert_free_space_to_extents(trans, block_group, path); 507 } 508 509out: 510 return ret; 511} 512 513EXPORT_FOR_TESTS 514int free_space_test_bit(struct btrfs_block_group *block_group, 515 struct btrfs_path *path, u64 offset) 516{ 517 struct extent_buffer *leaf; 518 struct btrfs_key key; 519 u64 found_start, found_end; 520 unsigned long ptr, i; 521 522 leaf = path->nodes[0]; 523 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 524 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY); 525 526 found_start = key.objectid; 527 found_end = key.objectid + key.offset; 528 ASSERT(offset >= found_start && offset < found_end); 529 530 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); 531 i = div_u64(offset - found_start, 532 block_group->fs_info->sectorsize); 533 return !!extent_buffer_test_bit(leaf, ptr, i); 534} 535 536static void free_space_set_bits(struct btrfs_trans_handle *trans, 537 struct btrfs_block_group *block_group, 538 struct btrfs_path *path, u64 *start, u64 *size, 539 int bit) 540{ 541 struct btrfs_fs_info *fs_info = block_group->fs_info; 542 struct extent_buffer *leaf; 543 struct btrfs_key key; 544 u64 end = *start + *size; 545 u64 found_start, found_end; 546 unsigned long ptr, first, last; 547 548 leaf = path->nodes[0]; 549 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 550 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY); 551 552 found_start = key.objectid; 553 found_end = key.objectid + key.offset; 554 ASSERT(*start >= found_start && *start < found_end); 555 ASSERT(end > found_start); 556 557 if (end > found_end) 558 end = found_end; 559 560 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); 561 first = (*start - found_start) >> fs_info->sectorsize_bits; 562 last = (end - found_start) >> fs_info->sectorsize_bits; 563 if (bit) 564 extent_buffer_bitmap_set(leaf, ptr, first, last - first); 565 else 566 extent_buffer_bitmap_clear(leaf, ptr, first, last - first); 567 btrfs_mark_buffer_dirty(trans, leaf); 568 569 *size -= end - *start; 570 *start = end; 571} 572 573/* 574 * We can't use btrfs_next_item() in modify_free_space_bitmap() because 575 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy 576 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're 577 * looking for. 578 */ 579static int free_space_next_bitmap(struct btrfs_trans_handle *trans, 580 struct btrfs_root *root, struct btrfs_path *p) 581{ 582 struct btrfs_key key; 583 584 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) { 585 p->slots[0]++; 586 return 0; 587 } 588 589 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]); 590 btrfs_release_path(p); 591 592 key.objectid += key.offset; 593 key.type = (u8)-1; 594 key.offset = (u64)-1; 595 596 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1); 597} 598 599/* 600 * If remove is 1, then we are removing free space, thus clearing bits in the 601 * bitmap. If remove is 0, then we are adding free space, thus setting bits in 602 * the bitmap. 603 */ 604static int modify_free_space_bitmap(struct btrfs_trans_handle *trans, 605 struct btrfs_block_group *block_group, 606 struct btrfs_path *path, 607 u64 start, u64 size, int remove) 608{ 609 struct btrfs_root *root = btrfs_free_space_root(block_group); 610 struct btrfs_key key; 611 u64 end = start + size; 612 u64 cur_start, cur_size; 613 int prev_bit, next_bit; 614 int new_extents; 615 int ret; 616 617 /* 618 * Read the bit for the block immediately before the extent of space if 619 * that block is within the block group. 620 */ 621 if (start > block_group->start) { 622 u64 prev_block = start - block_group->fs_info->sectorsize; 623 624 key.objectid = prev_block; 625 key.type = (u8)-1; 626 key.offset = (u64)-1; 627 628 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1); 629 if (ret) 630 goto out; 631 632 prev_bit = free_space_test_bit(block_group, path, prev_block); 633 634 /* The previous block may have been in the previous bitmap. */ 635 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 636 if (start >= key.objectid + key.offset) { 637 ret = free_space_next_bitmap(trans, root, path); 638 if (ret) 639 goto out; 640 } 641 } else { 642 key.objectid = start; 643 key.type = (u8)-1; 644 key.offset = (u64)-1; 645 646 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1); 647 if (ret) 648 goto out; 649 650 prev_bit = -1; 651 } 652 653 /* 654 * Iterate over all of the bitmaps overlapped by the extent of space, 655 * clearing/setting bits as required. 656 */ 657 cur_start = start; 658 cur_size = size; 659 while (1) { 660 free_space_set_bits(trans, block_group, path, &cur_start, &cur_size, 661 !remove); 662 if (cur_size == 0) 663 break; 664 ret = free_space_next_bitmap(trans, root, path); 665 if (ret) 666 goto out; 667 } 668 669 /* 670 * Read the bit for the block immediately after the extent of space if 671 * that block is within the block group. 672 */ 673 if (end < block_group->start + block_group->length) { 674 /* The next block may be in the next bitmap. */ 675 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 676 if (end >= key.objectid + key.offset) { 677 ret = free_space_next_bitmap(trans, root, path); 678 if (ret) 679 goto out; 680 } 681 682 next_bit = free_space_test_bit(block_group, path, end); 683 } else { 684 next_bit = -1; 685 } 686 687 if (remove) { 688 new_extents = -1; 689 if (prev_bit == 1) { 690 /* Leftover on the left. */ 691 new_extents++; 692 } 693 if (next_bit == 1) { 694 /* Leftover on the right. */ 695 new_extents++; 696 } 697 } else { 698 new_extents = 1; 699 if (prev_bit == 1) { 700 /* Merging with neighbor on the left. */ 701 new_extents--; 702 } 703 if (next_bit == 1) { 704 /* Merging with neighbor on the right. */ 705 new_extents--; 706 } 707 } 708 709 btrfs_release_path(path); 710 ret = update_free_space_extent_count(trans, block_group, path, 711 new_extents); 712 713out: 714 return ret; 715} 716 717static int remove_free_space_extent(struct btrfs_trans_handle *trans, 718 struct btrfs_block_group *block_group, 719 struct btrfs_path *path, 720 u64 start, u64 size) 721{ 722 struct btrfs_root *root = btrfs_free_space_root(block_group); 723 struct btrfs_key key; 724 u64 found_start, found_end; 725 u64 end = start + size; 726 int new_extents = -1; 727 int ret; 728 729 key.objectid = start; 730 key.type = (u8)-1; 731 key.offset = (u64)-1; 732 733 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); 734 if (ret) 735 goto out; 736 737 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 738 739 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY); 740 741 found_start = key.objectid; 742 found_end = key.objectid + key.offset; 743 ASSERT(start >= found_start && end <= found_end); 744 745 /* 746 * Okay, now that we've found the free space extent which contains the 747 * free space that we are removing, there are four cases: 748 * 749 * 1. We're using the whole extent: delete the key we found and 750 * decrement the free space extent count. 751 * 2. We are using part of the extent starting at the beginning: delete 752 * the key we found and insert a new key representing the leftover at 753 * the end. There is no net change in the number of extents. 754 * 3. We are using part of the extent ending at the end: delete the key 755 * we found and insert a new key representing the leftover at the 756 * beginning. There is no net change in the number of extents. 757 * 4. We are using part of the extent in the middle: delete the key we 758 * found and insert two new keys representing the leftovers on each 759 * side. Where we used to have one extent, we now have two, so increment 760 * the extent count. We may need to convert the block group to bitmaps 761 * as a result. 762 */ 763 764 /* Delete the existing key (cases 1-4). */ 765 ret = btrfs_del_item(trans, root, path); 766 if (ret) 767 goto out; 768 769 /* Add a key for leftovers at the beginning (cases 3 and 4). */ 770 if (start > found_start) { 771 key.objectid = found_start; 772 key.type = BTRFS_FREE_SPACE_EXTENT_KEY; 773 key.offset = start - found_start; 774 775 btrfs_release_path(path); 776 ret = btrfs_insert_empty_item(trans, root, path, &key, 0); 777 if (ret) 778 goto out; 779 new_extents++; 780 } 781 782 /* Add a key for leftovers at the end (cases 2 and 4). */ 783 if (end < found_end) { 784 key.objectid = end; 785 key.type = BTRFS_FREE_SPACE_EXTENT_KEY; 786 key.offset = found_end - end; 787 788 btrfs_release_path(path); 789 ret = btrfs_insert_empty_item(trans, root, path, &key, 0); 790 if (ret) 791 goto out; 792 new_extents++; 793 } 794 795 btrfs_release_path(path); 796 ret = update_free_space_extent_count(trans, block_group, path, 797 new_extents); 798 799out: 800 return ret; 801} 802 803EXPORT_FOR_TESTS 804int __remove_from_free_space_tree(struct btrfs_trans_handle *trans, 805 struct btrfs_block_group *block_group, 806 struct btrfs_path *path, u64 start, u64 size) 807{ 808 struct btrfs_free_space_info *info; 809 u32 flags; 810 int ret; 811 812 if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) { 813 ret = __add_block_group_free_space(trans, block_group, path); 814 if (ret) 815 return ret; 816 } 817 818 info = search_free_space_info(NULL, block_group, path, 0); 819 if (IS_ERR(info)) 820 return PTR_ERR(info); 821 flags = btrfs_free_space_flags(path->nodes[0], info); 822 btrfs_release_path(path); 823 824 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) { 825 return modify_free_space_bitmap(trans, block_group, path, 826 start, size, 1); 827 } else { 828 return remove_free_space_extent(trans, block_group, path, 829 start, size); 830 } 831} 832 833int remove_from_free_space_tree(struct btrfs_trans_handle *trans, 834 u64 start, u64 size) 835{ 836 struct btrfs_block_group *block_group; 837 struct btrfs_path *path; 838 int ret; 839 840 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE)) 841 return 0; 842 843 path = btrfs_alloc_path(); 844 if (!path) { 845 ret = -ENOMEM; 846 goto out; 847 } 848 849 block_group = btrfs_lookup_block_group(trans->fs_info, start); 850 if (!block_group) { 851 ASSERT(0); 852 ret = -ENOENT; 853 goto out; 854 } 855 856 mutex_lock(&block_group->free_space_lock); 857 ret = __remove_from_free_space_tree(trans, block_group, path, start, 858 size); 859 mutex_unlock(&block_group->free_space_lock); 860 861 btrfs_put_block_group(block_group); 862out: 863 btrfs_free_path(path); 864 if (ret) 865 btrfs_abort_transaction(trans, ret); 866 return ret; 867} 868 869static int add_free_space_extent(struct btrfs_trans_handle *trans, 870 struct btrfs_block_group *block_group, 871 struct btrfs_path *path, 872 u64 start, u64 size) 873{ 874 struct btrfs_root *root = btrfs_free_space_root(block_group); 875 struct btrfs_key key, new_key; 876 u64 found_start, found_end; 877 u64 end = start + size; 878 int new_extents = 1; 879 int ret; 880 881 /* 882 * We are adding a new extent of free space, but we need to merge 883 * extents. There are four cases here: 884 * 885 * 1. The new extent does not have any immediate neighbors to merge 886 * with: add the new key and increment the free space extent count. We 887 * may need to convert the block group to bitmaps as a result. 888 * 2. The new extent has an immediate neighbor before it: remove the 889 * previous key and insert a new key combining both of them. There is no 890 * net change in the number of extents. 891 * 3. The new extent has an immediate neighbor after it: remove the next 892 * key and insert a new key combining both of them. There is no net 893 * change in the number of extents. 894 * 4. The new extent has immediate neighbors on both sides: remove both 895 * of the keys and insert a new key combining all of them. Where we used 896 * to have two extents, we now have one, so decrement the extent count. 897 */ 898 899 new_key.objectid = start; 900 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY; 901 new_key.offset = size; 902 903 /* Search for a neighbor on the left. */ 904 if (start == block_group->start) 905 goto right; 906 key.objectid = start - 1; 907 key.type = (u8)-1; 908 key.offset = (u64)-1; 909 910 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); 911 if (ret) 912 goto out; 913 914 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 915 916 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) { 917 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY); 918 btrfs_release_path(path); 919 goto right; 920 } 921 922 found_start = key.objectid; 923 found_end = key.objectid + key.offset; 924 ASSERT(found_start >= block_group->start && 925 found_end > block_group->start); 926 ASSERT(found_start < start && found_end <= start); 927 928 /* 929 * Delete the neighbor on the left and absorb it into the new key (cases 930 * 2 and 4). 931 */ 932 if (found_end == start) { 933 ret = btrfs_del_item(trans, root, path); 934 if (ret) 935 goto out; 936 new_key.objectid = found_start; 937 new_key.offset += key.offset; 938 new_extents--; 939 } 940 btrfs_release_path(path); 941 942right: 943 /* Search for a neighbor on the right. */ 944 if (end == block_group->start + block_group->length) 945 goto insert; 946 key.objectid = end; 947 key.type = (u8)-1; 948 key.offset = (u64)-1; 949 950 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); 951 if (ret) 952 goto out; 953 954 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 955 956 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) { 957 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY); 958 btrfs_release_path(path); 959 goto insert; 960 } 961 962 found_start = key.objectid; 963 found_end = key.objectid + key.offset; 964 ASSERT(found_start >= block_group->start && 965 found_end > block_group->start); 966 ASSERT((found_start < start && found_end <= start) || 967 (found_start >= end && found_end > end)); 968 969 /* 970 * Delete the neighbor on the right and absorb it into the new key 971 * (cases 3 and 4). 972 */ 973 if (found_start == end) { 974 ret = btrfs_del_item(trans, root, path); 975 if (ret) 976 goto out; 977 new_key.offset += key.offset; 978 new_extents--; 979 } 980 btrfs_release_path(path); 981 982insert: 983 /* Insert the new key (cases 1-4). */ 984 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0); 985 if (ret) 986 goto out; 987 988 btrfs_release_path(path); 989 ret = update_free_space_extent_count(trans, block_group, path, 990 new_extents); 991 992out: 993 return ret; 994} 995 996EXPORT_FOR_TESTS 997int __add_to_free_space_tree(struct btrfs_trans_handle *trans, 998 struct btrfs_block_group *block_group, 999 struct btrfs_path *path, u64 start, u64 size) 1000{ 1001 struct btrfs_free_space_info *info; 1002 u32 flags; 1003 int ret; 1004 1005 if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) { 1006 ret = __add_block_group_free_space(trans, block_group, path); 1007 if (ret) 1008 return ret; 1009 } 1010 1011 info = search_free_space_info(NULL, block_group, path, 0); 1012 if (IS_ERR(info)) 1013 return PTR_ERR(info); 1014 flags = btrfs_free_space_flags(path->nodes[0], info); 1015 btrfs_release_path(path); 1016 1017 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) { 1018 return modify_free_space_bitmap(trans, block_group, path, 1019 start, size, 0); 1020 } else { 1021 return add_free_space_extent(trans, block_group, path, start, 1022 size); 1023 } 1024} 1025 1026int add_to_free_space_tree(struct btrfs_trans_handle *trans, 1027 u64 start, u64 size) 1028{ 1029 struct btrfs_block_group *block_group; 1030 struct btrfs_path *path; 1031 int ret; 1032 1033 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE)) 1034 return 0; 1035 1036 path = btrfs_alloc_path(); 1037 if (!path) { 1038 ret = -ENOMEM; 1039 goto out; 1040 } 1041 1042 block_group = btrfs_lookup_block_group(trans->fs_info, start); 1043 if (!block_group) { 1044 ASSERT(0); 1045 ret = -ENOENT; 1046 goto out; 1047 } 1048 1049 mutex_lock(&block_group->free_space_lock); 1050 ret = __add_to_free_space_tree(trans, block_group, path, start, size); 1051 mutex_unlock(&block_group->free_space_lock); 1052 1053 btrfs_put_block_group(block_group); 1054out: 1055 btrfs_free_path(path); 1056 if (ret) 1057 btrfs_abort_transaction(trans, ret); 1058 return ret; 1059} 1060 1061/* 1062 * Populate the free space tree by walking the extent tree. Operations on the 1063 * extent tree that happen as a result of writes to the free space tree will go 1064 * through the normal add/remove hooks. 1065 */ 1066static int populate_free_space_tree(struct btrfs_trans_handle *trans, 1067 struct btrfs_block_group *block_group) 1068{ 1069 struct btrfs_root *extent_root; 1070 struct btrfs_path *path, *path2; 1071 struct btrfs_key key; 1072 u64 start, end; 1073 int ret; 1074 1075 path = btrfs_alloc_path(); 1076 if (!path) 1077 return -ENOMEM; 1078 path->reada = READA_FORWARD; 1079 1080 path2 = btrfs_alloc_path(); 1081 if (!path2) { 1082 btrfs_free_path(path); 1083 return -ENOMEM; 1084 } 1085 1086 ret = add_new_free_space_info(trans, block_group, path2); 1087 if (ret) 1088 goto out; 1089 1090 mutex_lock(&block_group->free_space_lock); 1091 1092 /* 1093 * Iterate through all of the extent and metadata items in this block 1094 * group, adding the free space between them and the free space at the 1095 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than 1096 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's 1097 * contained in. 1098 */ 1099 key.objectid = block_group->start; 1100 key.type = BTRFS_EXTENT_ITEM_KEY; 1101 key.offset = 0; 1102 1103 extent_root = btrfs_extent_root(trans->fs_info, key.objectid); 1104 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0); 1105 if (ret < 0) 1106 goto out_locked; 1107 ASSERT(ret == 0); 1108 1109 start = block_group->start; 1110 end = block_group->start + block_group->length; 1111 while (1) { 1112 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 1113 1114 if (key.type == BTRFS_EXTENT_ITEM_KEY || 1115 key.type == BTRFS_METADATA_ITEM_KEY) { 1116 if (key.objectid >= end) 1117 break; 1118 1119 if (start < key.objectid) { 1120 ret = __add_to_free_space_tree(trans, 1121 block_group, 1122 path2, start, 1123 key.objectid - 1124 start); 1125 if (ret) 1126 goto out_locked; 1127 } 1128 start = key.objectid; 1129 if (key.type == BTRFS_METADATA_ITEM_KEY) 1130 start += trans->fs_info->nodesize; 1131 else 1132 start += key.offset; 1133 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) { 1134 if (key.objectid != block_group->start) 1135 break; 1136 } 1137 1138 ret = btrfs_next_item(extent_root, path); 1139 if (ret < 0) 1140 goto out_locked; 1141 if (ret) 1142 break; 1143 } 1144 if (start < end) { 1145 ret = __add_to_free_space_tree(trans, block_group, path2, 1146 start, end - start); 1147 if (ret) 1148 goto out_locked; 1149 } 1150 1151 ret = 0; 1152out_locked: 1153 mutex_unlock(&block_group->free_space_lock); 1154out: 1155 btrfs_free_path(path2); 1156 btrfs_free_path(path); 1157 return ret; 1158} 1159 1160int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info) 1161{ 1162 struct btrfs_trans_handle *trans; 1163 struct btrfs_root *tree_root = fs_info->tree_root; 1164 struct btrfs_root *free_space_root; 1165 struct btrfs_block_group *block_group; 1166 struct rb_node *node; 1167 int ret; 1168 1169 trans = btrfs_start_transaction(tree_root, 0); 1170 if (IS_ERR(trans)) 1171 return PTR_ERR(trans); 1172 1173 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags); 1174 set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags); 1175 free_space_root = btrfs_create_tree(trans, 1176 BTRFS_FREE_SPACE_TREE_OBJECTID); 1177 if (IS_ERR(free_space_root)) { 1178 ret = PTR_ERR(free_space_root); 1179 btrfs_abort_transaction(trans, ret); 1180 btrfs_end_transaction(trans); 1181 goto out_clear; 1182 } 1183 ret = btrfs_global_root_insert(free_space_root); 1184 if (ret) { 1185 btrfs_put_root(free_space_root); 1186 btrfs_abort_transaction(trans, ret); 1187 btrfs_end_transaction(trans); 1188 goto out_clear; 1189 } 1190 1191 node = rb_first_cached(&fs_info->block_group_cache_tree); 1192 while (node) { 1193 block_group = rb_entry(node, struct btrfs_block_group, 1194 cache_node); 1195 ret = populate_free_space_tree(trans, block_group); 1196 if (ret) { 1197 btrfs_abort_transaction(trans, ret); 1198 btrfs_end_transaction(trans); 1199 goto out_clear; 1200 } 1201 node = rb_next(node); 1202 } 1203 1204 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE); 1205 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); 1206 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags); 1207 ret = btrfs_commit_transaction(trans); 1208 1209 /* 1210 * Now that we've committed the transaction any reading of our commit 1211 * root will be safe, so we can cache from the free space tree now. 1212 */ 1213 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags); 1214 return ret; 1215 1216out_clear: 1217 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags); 1218 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags); 1219 return ret; 1220} 1221 1222static int clear_free_space_tree(struct btrfs_trans_handle *trans, 1223 struct btrfs_root *root) 1224{ 1225 struct btrfs_path *path; 1226 struct btrfs_key key; 1227 int nr; 1228 int ret; 1229 1230 path = btrfs_alloc_path(); 1231 if (!path) 1232 return -ENOMEM; 1233 1234 key.objectid = 0; 1235 key.type = 0; 1236 key.offset = 0; 1237 1238 while (1) { 1239 ret = btrfs_search_slot(trans, root, &key, path, -1, 1); 1240 if (ret < 0) 1241 goto out; 1242 1243 nr = btrfs_header_nritems(path->nodes[0]); 1244 if (!nr) 1245 break; 1246 1247 path->slots[0] = 0; 1248 ret = btrfs_del_items(trans, root, path, 0, nr); 1249 if (ret) 1250 goto out; 1251 1252 btrfs_release_path(path); 1253 } 1254 1255 ret = 0; 1256out: 1257 btrfs_free_path(path); 1258 return ret; 1259} 1260 1261int btrfs_delete_free_space_tree(struct btrfs_fs_info *fs_info) 1262{ 1263 struct btrfs_trans_handle *trans; 1264 struct btrfs_root *tree_root = fs_info->tree_root; 1265 struct btrfs_key key = { 1266 .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID, 1267 .type = BTRFS_ROOT_ITEM_KEY, 1268 .offset = 0, 1269 }; 1270 struct btrfs_root *free_space_root = btrfs_global_root(fs_info, &key); 1271 int ret; 1272 1273 trans = btrfs_start_transaction(tree_root, 0); 1274 if (IS_ERR(trans)) 1275 return PTR_ERR(trans); 1276 1277 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE); 1278 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); 1279 1280 ret = clear_free_space_tree(trans, free_space_root); 1281 if (ret) { 1282 btrfs_abort_transaction(trans, ret); 1283 btrfs_end_transaction(trans); 1284 return ret; 1285 } 1286 1287 ret = btrfs_del_root(trans, &free_space_root->root_key); 1288 if (ret) { 1289 btrfs_abort_transaction(trans, ret); 1290 btrfs_end_transaction(trans); 1291 return ret; 1292 } 1293 1294 btrfs_global_root_delete(free_space_root); 1295 1296 spin_lock(&fs_info->trans_lock); 1297 list_del(&free_space_root->dirty_list); 1298 spin_unlock(&fs_info->trans_lock); 1299 1300 btrfs_tree_lock(free_space_root->node); 1301 btrfs_clear_buffer_dirty(trans, free_space_root->node); 1302 btrfs_tree_unlock(free_space_root->node); 1303 btrfs_free_tree_block(trans, btrfs_root_id(free_space_root), 1304 free_space_root->node, 0, 1); 1305 1306 btrfs_put_root(free_space_root); 1307 1308 return btrfs_commit_transaction(trans); 1309} 1310 1311int btrfs_rebuild_free_space_tree(struct btrfs_fs_info *fs_info) 1312{ 1313 struct btrfs_trans_handle *trans; 1314 struct btrfs_key key = { 1315 .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID, 1316 .type = BTRFS_ROOT_ITEM_KEY, 1317 .offset = 0, 1318 }; 1319 struct btrfs_root *free_space_root = btrfs_global_root(fs_info, &key); 1320 struct rb_node *node; 1321 int ret; 1322 1323 trans = btrfs_start_transaction(free_space_root, 1); 1324 if (IS_ERR(trans)) 1325 return PTR_ERR(trans); 1326 1327 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags); 1328 set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags); 1329 1330 ret = clear_free_space_tree(trans, free_space_root); 1331 if (ret) { 1332 btrfs_abort_transaction(trans, ret); 1333 btrfs_end_transaction(trans); 1334 return ret; 1335 } 1336 1337 node = rb_first_cached(&fs_info->block_group_cache_tree); 1338 while (node) { 1339 struct btrfs_block_group *block_group; 1340 1341 block_group = rb_entry(node, struct btrfs_block_group, 1342 cache_node); 1343 ret = populate_free_space_tree(trans, block_group); 1344 if (ret) { 1345 btrfs_abort_transaction(trans, ret); 1346 btrfs_end_transaction(trans); 1347 return ret; 1348 } 1349 node = rb_next(node); 1350 } 1351 1352 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE); 1353 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); 1354 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags); 1355 1356 ret = btrfs_commit_transaction(trans); 1357 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags); 1358 return ret; 1359} 1360 1361static int __add_block_group_free_space(struct btrfs_trans_handle *trans, 1362 struct btrfs_block_group *block_group, 1363 struct btrfs_path *path) 1364{ 1365 int ret; 1366 1367 clear_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags); 1368 1369 ret = add_new_free_space_info(trans, block_group, path); 1370 if (ret) 1371 return ret; 1372 1373 return __add_to_free_space_tree(trans, block_group, path, 1374 block_group->start, 1375 block_group->length); 1376} 1377 1378int add_block_group_free_space(struct btrfs_trans_handle *trans, 1379 struct btrfs_block_group *block_group) 1380{ 1381 struct btrfs_fs_info *fs_info = trans->fs_info; 1382 struct btrfs_path *path = NULL; 1383 int ret = 0; 1384 1385 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) 1386 return 0; 1387 1388 mutex_lock(&block_group->free_space_lock); 1389 if (!test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) 1390 goto out; 1391 1392 path = btrfs_alloc_path(); 1393 if (!path) { 1394 ret = -ENOMEM; 1395 goto out; 1396 } 1397 1398 ret = __add_block_group_free_space(trans, block_group, path); 1399 1400out: 1401 btrfs_free_path(path); 1402 mutex_unlock(&block_group->free_space_lock); 1403 if (ret) 1404 btrfs_abort_transaction(trans, ret); 1405 return ret; 1406} 1407 1408int remove_block_group_free_space(struct btrfs_trans_handle *trans, 1409 struct btrfs_block_group *block_group) 1410{ 1411 struct btrfs_root *root = btrfs_free_space_root(block_group); 1412 struct btrfs_path *path; 1413 struct btrfs_key key, found_key; 1414 struct extent_buffer *leaf; 1415 u64 start, end; 1416 int done = 0, nr; 1417 int ret; 1418 1419 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE)) 1420 return 0; 1421 1422 if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) { 1423 /* We never added this block group to the free space tree. */ 1424 return 0; 1425 } 1426 1427 path = btrfs_alloc_path(); 1428 if (!path) { 1429 ret = -ENOMEM; 1430 goto out; 1431 } 1432 1433 start = block_group->start; 1434 end = block_group->start + block_group->length; 1435 1436 key.objectid = end - 1; 1437 key.type = (u8)-1; 1438 key.offset = (u64)-1; 1439 1440 while (!done) { 1441 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); 1442 if (ret) 1443 goto out; 1444 1445 leaf = path->nodes[0]; 1446 nr = 0; 1447 path->slots[0]++; 1448 while (path->slots[0] > 0) { 1449 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1); 1450 1451 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) { 1452 ASSERT(found_key.objectid == block_group->start); 1453 ASSERT(found_key.offset == block_group->length); 1454 done = 1; 1455 nr++; 1456 path->slots[0]--; 1457 break; 1458 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY || 1459 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) { 1460 ASSERT(found_key.objectid >= start); 1461 ASSERT(found_key.objectid < end); 1462 ASSERT(found_key.objectid + found_key.offset <= end); 1463 nr++; 1464 path->slots[0]--; 1465 } else { 1466 ASSERT(0); 1467 } 1468 } 1469 1470 ret = btrfs_del_items(trans, root, path, path->slots[0], nr); 1471 if (ret) 1472 goto out; 1473 btrfs_release_path(path); 1474 } 1475 1476 ret = 0; 1477out: 1478 btrfs_free_path(path); 1479 if (ret) 1480 btrfs_abort_transaction(trans, ret); 1481 return ret; 1482} 1483 1484static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl, 1485 struct btrfs_path *path, 1486 u32 expected_extent_count) 1487{ 1488 struct btrfs_block_group *block_group; 1489 struct btrfs_fs_info *fs_info; 1490 struct btrfs_root *root; 1491 struct btrfs_key key; 1492 int prev_bit = 0, bit; 1493 /* Initialize to silence GCC. */ 1494 u64 extent_start = 0; 1495 u64 end, offset; 1496 u64 total_found = 0; 1497 u32 extent_count = 0; 1498 int ret; 1499 1500 block_group = caching_ctl->block_group; 1501 fs_info = block_group->fs_info; 1502 root = btrfs_free_space_root(block_group); 1503 1504 end = block_group->start + block_group->length; 1505 1506 while (1) { 1507 ret = btrfs_next_item(root, path); 1508 if (ret < 0) 1509 goto out; 1510 if (ret) 1511 break; 1512 1513 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 1514 1515 if (key.type == BTRFS_FREE_SPACE_INFO_KEY) 1516 break; 1517 1518 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY); 1519 ASSERT(key.objectid < end && key.objectid + key.offset <= end); 1520 1521 offset = key.objectid; 1522 while (offset < key.objectid + key.offset) { 1523 bit = free_space_test_bit(block_group, path, offset); 1524 if (prev_bit == 0 && bit == 1) { 1525 extent_start = offset; 1526 } else if (prev_bit == 1 && bit == 0) { 1527 u64 space_added; 1528 1529 ret = btrfs_add_new_free_space(block_group, 1530 extent_start, 1531 offset, 1532 &space_added); 1533 if (ret) 1534 goto out; 1535 total_found += space_added; 1536 if (total_found > CACHING_CTL_WAKE_UP) { 1537 total_found = 0; 1538 wake_up(&caching_ctl->wait); 1539 } 1540 extent_count++; 1541 } 1542 prev_bit = bit; 1543 offset += fs_info->sectorsize; 1544 } 1545 } 1546 if (prev_bit == 1) { 1547 ret = btrfs_add_new_free_space(block_group, extent_start, end, NULL); 1548 if (ret) 1549 goto out; 1550 extent_count++; 1551 } 1552 1553 if (extent_count != expected_extent_count) { 1554 btrfs_err(fs_info, 1555 "incorrect extent count for %llu; counted %u, expected %u", 1556 block_group->start, extent_count, 1557 expected_extent_count); 1558 ASSERT(0); 1559 ret = -EIO; 1560 goto out; 1561 } 1562 1563 ret = 0; 1564out: 1565 return ret; 1566} 1567 1568static int load_free_space_extents(struct btrfs_caching_control *caching_ctl, 1569 struct btrfs_path *path, 1570 u32 expected_extent_count) 1571{ 1572 struct btrfs_block_group *block_group; 1573 struct btrfs_fs_info *fs_info; 1574 struct btrfs_root *root; 1575 struct btrfs_key key; 1576 u64 end; 1577 u64 total_found = 0; 1578 u32 extent_count = 0; 1579 int ret; 1580 1581 block_group = caching_ctl->block_group; 1582 fs_info = block_group->fs_info; 1583 root = btrfs_free_space_root(block_group); 1584 1585 end = block_group->start + block_group->length; 1586 1587 while (1) { 1588 u64 space_added; 1589 1590 ret = btrfs_next_item(root, path); 1591 if (ret < 0) 1592 goto out; 1593 if (ret) 1594 break; 1595 1596 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 1597 1598 if (key.type == BTRFS_FREE_SPACE_INFO_KEY) 1599 break; 1600 1601 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY); 1602 ASSERT(key.objectid < end && key.objectid + key.offset <= end); 1603 1604 ret = btrfs_add_new_free_space(block_group, key.objectid, 1605 key.objectid + key.offset, 1606 &space_added); 1607 if (ret) 1608 goto out; 1609 total_found += space_added; 1610 if (total_found > CACHING_CTL_WAKE_UP) { 1611 total_found = 0; 1612 wake_up(&caching_ctl->wait); 1613 } 1614 extent_count++; 1615 } 1616 1617 if (extent_count != expected_extent_count) { 1618 btrfs_err(fs_info, 1619 "incorrect extent count for %llu; counted %u, expected %u", 1620 block_group->start, extent_count, 1621 expected_extent_count); 1622 ASSERT(0); 1623 ret = -EIO; 1624 goto out; 1625 } 1626 1627 ret = 0; 1628out: 1629 return ret; 1630} 1631 1632int load_free_space_tree(struct btrfs_caching_control *caching_ctl) 1633{ 1634 struct btrfs_block_group *block_group; 1635 struct btrfs_free_space_info *info; 1636 struct btrfs_path *path; 1637 u32 extent_count, flags; 1638 int ret; 1639 1640 block_group = caching_ctl->block_group; 1641 1642 path = btrfs_alloc_path(); 1643 if (!path) 1644 return -ENOMEM; 1645 1646 /* 1647 * Just like caching_thread() doesn't want to deadlock on the extent 1648 * tree, we don't want to deadlock on the free space tree. 1649 */ 1650 path->skip_locking = 1; 1651 path->search_commit_root = 1; 1652 path->reada = READA_FORWARD; 1653 1654 info = search_free_space_info(NULL, block_group, path, 0); 1655 if (IS_ERR(info)) { 1656 ret = PTR_ERR(info); 1657 goto out; 1658 } 1659 extent_count = btrfs_free_space_extent_count(path->nodes[0], info); 1660 flags = btrfs_free_space_flags(path->nodes[0], info); 1661 1662 /* 1663 * We left path pointing to the free space info item, so now 1664 * load_free_space_foo can just iterate through the free space tree from 1665 * there. 1666 */ 1667 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) 1668 ret = load_free_space_bitmaps(caching_ctl, path, extent_count); 1669 else 1670 ret = load_free_space_extents(caching_ctl, path, extent_count); 1671 1672out: 1673 btrfs_free_path(path); 1674 return ret; 1675} 1676