1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2015 Facebook. All rights reserved.
6 #include <linux/kernel.h>
7 #include <linux/sched/mm.h>
11 #include "free-space-tree.h"
12 #include "transaction.h"
13 #include "block-group.h"
15 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
16 struct btrfs_block_group *block_group,
17 struct btrfs_path *path);
19 void set_free_space_tree_thresholds(struct btrfs_block_group *cache)
23 u64 num_bitmaps, total_bitmap_size;
25 if (WARN_ON(cache->length == 0))
26 btrfs_warn(cache->fs_info, "block group %llu length is zero",
30 * We convert to bitmaps when the disk space required for using extents
31 * exceeds that required for using bitmaps.
33 bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
34 num_bitmaps = div_u64(cache->length + bitmap_range - 1, bitmap_range);
35 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
36 total_bitmap_size = num_bitmaps * bitmap_size;
37 cache->bitmap_high_thresh = div_u64(total_bitmap_size,
38 sizeof(struct btrfs_item));
41 * We allow for a small buffer between the high threshold and low
42 * threshold to avoid thrashing back and forth between the two formats.
44 if (cache->bitmap_high_thresh > 100)
45 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
47 cache->bitmap_low_thresh = 0;
50 static int add_new_free_space_info(struct btrfs_trans_handle *trans,
51 struct btrfs_block_group *block_group,
52 struct btrfs_path *path)
54 struct btrfs_root *root = trans->fs_info->free_space_root;
55 struct btrfs_free_space_info *info;
57 struct extent_buffer *leaf;
60 key.objectid = block_group->start;
61 key.type = BTRFS_FREE_SPACE_INFO_KEY;
62 key.offset = block_group->length;
64 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
68 leaf = path->nodes[0];
69 info = btrfs_item_ptr(leaf, path->slots[0],
70 struct btrfs_free_space_info);
71 btrfs_set_free_space_extent_count(leaf, info, 0);
72 btrfs_set_free_space_flags(leaf, info, 0);
73 btrfs_mark_buffer_dirty(leaf);
77 btrfs_release_path(path);
82 struct btrfs_free_space_info *search_free_space_info(
83 struct btrfs_trans_handle *trans,
84 struct btrfs_block_group *block_group,
85 struct btrfs_path *path, int cow)
87 struct btrfs_fs_info *fs_info = block_group->fs_info;
88 struct btrfs_root *root = fs_info->free_space_root;
92 key.objectid = block_group->start;
93 key.type = BTRFS_FREE_SPACE_INFO_KEY;
94 key.offset = block_group->length;
96 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
100 btrfs_warn(fs_info, "missing free space info for %llu",
103 return ERR_PTR(-ENOENT);
106 return btrfs_item_ptr(path->nodes[0], path->slots[0],
107 struct btrfs_free_space_info);
111 * btrfs_search_slot() but we're looking for the greatest key less than the
114 static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
115 struct btrfs_root *root,
116 struct btrfs_key *key, struct btrfs_path *p,
117 int ins_len, int cow)
121 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
130 if (p->slots[0] == 0) {
139 static inline u32 free_space_bitmap_size(const struct btrfs_fs_info *fs_info,
142 return DIV_ROUND_UP(size >> fs_info->sectorsize_bits, BITS_PER_BYTE);
145 static unsigned long *alloc_bitmap(u32 bitmap_size)
148 unsigned int nofs_flag;
149 u32 bitmap_rounded_size = round_up(bitmap_size, sizeof(unsigned long));
152 * GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse
153 * into the filesystem as the free space bitmap can be modified in the
154 * critical section of a transaction commit.
156 * TODO: push the memalloc_nofs_{save,restore}() to the caller where we
157 * know that recursion is unsafe.
159 nofs_flag = memalloc_nofs_save();
160 ret = kvzalloc(bitmap_rounded_size, GFP_KERNEL);
161 memalloc_nofs_restore(nofs_flag);
165 static void le_bitmap_set(unsigned long *map, unsigned int start, int len)
167 u8 *p = ((u8 *)map) + BIT_BYTE(start);
168 const unsigned int size = start + len;
169 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
170 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
172 while (len - bits_to_set >= 0) {
175 bits_to_set = BITS_PER_BYTE;
180 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
186 int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
187 struct btrfs_block_group *block_group,
188 struct btrfs_path *path)
190 struct btrfs_fs_info *fs_info = trans->fs_info;
191 struct btrfs_root *root = fs_info->free_space_root;
192 struct btrfs_free_space_info *info;
193 struct btrfs_key key, found_key;
194 struct extent_buffer *leaf;
195 unsigned long *bitmap;
199 u32 bitmap_size, flags, expected_extent_count;
200 u32 extent_count = 0;
204 bitmap_size = free_space_bitmap_size(fs_info, block_group->length);
205 bitmap = alloc_bitmap(bitmap_size);
211 start = block_group->start;
212 end = block_group->start + block_group->length;
214 key.objectid = end - 1;
216 key.offset = (u64)-1;
219 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
223 leaf = path->nodes[0];
226 while (path->slots[0] > 0) {
227 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
229 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
230 ASSERT(found_key.objectid == block_group->start);
231 ASSERT(found_key.offset == block_group->length);
234 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
237 ASSERT(found_key.objectid >= start);
238 ASSERT(found_key.objectid < end);
239 ASSERT(found_key.objectid + found_key.offset <= end);
241 first = div_u64(found_key.objectid - start,
242 fs_info->sectorsize);
243 last = div_u64(found_key.objectid + found_key.offset - start,
244 fs_info->sectorsize);
245 le_bitmap_set(bitmap, first, last - first);
255 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
258 btrfs_release_path(path);
261 info = search_free_space_info(trans, block_group, path, 1);
266 leaf = path->nodes[0];
267 flags = btrfs_free_space_flags(leaf, info);
268 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
269 btrfs_set_free_space_flags(leaf, info, flags);
270 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
271 btrfs_mark_buffer_dirty(leaf);
272 btrfs_release_path(path);
274 if (extent_count != expected_extent_count) {
276 "incorrect extent count for %llu; counted %u, expected %u",
277 block_group->start, extent_count,
278 expected_extent_count);
284 bitmap_cursor = (char *)bitmap;
285 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
292 extent_size = min(end - i, bitmap_range);
293 data_size = free_space_bitmap_size(fs_info, extent_size);
296 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
297 key.offset = extent_size;
299 ret = btrfs_insert_empty_item(trans, root, path, &key,
304 leaf = path->nodes[0];
305 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
306 write_extent_buffer(leaf, bitmap_cursor, ptr,
308 btrfs_mark_buffer_dirty(leaf);
309 btrfs_release_path(path);
312 bitmap_cursor += data_size;
319 btrfs_abort_transaction(trans, ret);
324 int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
325 struct btrfs_block_group *block_group,
326 struct btrfs_path *path)
328 struct btrfs_fs_info *fs_info = trans->fs_info;
329 struct btrfs_root *root = fs_info->free_space_root;
330 struct btrfs_free_space_info *info;
331 struct btrfs_key key, found_key;
332 struct extent_buffer *leaf;
333 unsigned long *bitmap;
335 u32 bitmap_size, flags, expected_extent_count;
336 unsigned long nrbits, start_bit, end_bit;
337 u32 extent_count = 0;
341 bitmap_size = free_space_bitmap_size(fs_info, block_group->length);
342 bitmap = alloc_bitmap(bitmap_size);
348 start = block_group->start;
349 end = block_group->start + block_group->length;
351 key.objectid = end - 1;
353 key.offset = (u64)-1;
356 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
360 leaf = path->nodes[0];
363 while (path->slots[0] > 0) {
364 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
366 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
367 ASSERT(found_key.objectid == block_group->start);
368 ASSERT(found_key.offset == block_group->length);
371 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
374 u32 bitmap_pos, data_size;
376 ASSERT(found_key.objectid >= start);
377 ASSERT(found_key.objectid < end);
378 ASSERT(found_key.objectid + found_key.offset <= end);
380 bitmap_pos = div_u64(found_key.objectid - start,
381 fs_info->sectorsize *
383 bitmap_cursor = ((char *)bitmap) + bitmap_pos;
384 data_size = free_space_bitmap_size(fs_info,
387 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
388 read_extent_buffer(leaf, bitmap_cursor, ptr,
398 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
401 btrfs_release_path(path);
404 info = search_free_space_info(trans, block_group, path, 1);
409 leaf = path->nodes[0];
410 flags = btrfs_free_space_flags(leaf, info);
411 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
412 btrfs_set_free_space_flags(leaf, info, flags);
413 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
414 btrfs_mark_buffer_dirty(leaf);
415 btrfs_release_path(path);
417 nrbits = block_group->length >> block_group->fs_info->sectorsize_bits;
418 start_bit = find_next_bit_le(bitmap, nrbits, 0);
420 while (start_bit < nrbits) {
421 end_bit = find_next_zero_bit_le(bitmap, nrbits, start_bit);
422 ASSERT(start_bit < end_bit);
424 key.objectid = start + start_bit * block_group->fs_info->sectorsize;
425 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
426 key.offset = (end_bit - start_bit) * block_group->fs_info->sectorsize;
428 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
431 btrfs_release_path(path);
435 start_bit = find_next_bit_le(bitmap, nrbits, end_bit);
438 if (extent_count != expected_extent_count) {
440 "incorrect extent count for %llu; counted %u, expected %u",
441 block_group->start, extent_count,
442 expected_extent_count);
452 btrfs_abort_transaction(trans, ret);
456 static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
457 struct btrfs_block_group *block_group,
458 struct btrfs_path *path,
461 struct btrfs_free_space_info *info;
466 if (new_extents == 0)
469 info = search_free_space_info(trans, block_group, path, 1);
474 flags = btrfs_free_space_flags(path->nodes[0], info);
475 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
477 extent_count += new_extents;
478 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
479 btrfs_mark_buffer_dirty(path->nodes[0]);
480 btrfs_release_path(path);
482 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
483 extent_count > block_group->bitmap_high_thresh) {
484 ret = convert_free_space_to_bitmaps(trans, block_group, path);
485 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
486 extent_count < block_group->bitmap_low_thresh) {
487 ret = convert_free_space_to_extents(trans, block_group, path);
495 int free_space_test_bit(struct btrfs_block_group *block_group,
496 struct btrfs_path *path, u64 offset)
498 struct extent_buffer *leaf;
499 struct btrfs_key key;
500 u64 found_start, found_end;
501 unsigned long ptr, i;
503 leaf = path->nodes[0];
504 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
505 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
507 found_start = key.objectid;
508 found_end = key.objectid + key.offset;
509 ASSERT(offset >= found_start && offset < found_end);
511 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
512 i = div_u64(offset - found_start,
513 block_group->fs_info->sectorsize);
514 return !!extent_buffer_test_bit(leaf, ptr, i);
517 static void free_space_set_bits(struct btrfs_block_group *block_group,
518 struct btrfs_path *path, u64 *start, u64 *size,
521 struct btrfs_fs_info *fs_info = block_group->fs_info;
522 struct extent_buffer *leaf;
523 struct btrfs_key key;
524 u64 end = *start + *size;
525 u64 found_start, found_end;
526 unsigned long ptr, first, last;
528 leaf = path->nodes[0];
529 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
530 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
532 found_start = key.objectid;
533 found_end = key.objectid + key.offset;
534 ASSERT(*start >= found_start && *start < found_end);
535 ASSERT(end > found_start);
540 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
541 first = (*start - found_start) >> fs_info->sectorsize_bits;
542 last = (end - found_start) >> fs_info->sectorsize_bits;
544 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
546 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
547 btrfs_mark_buffer_dirty(leaf);
549 *size -= end - *start;
554 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
555 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
556 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
559 static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
560 struct btrfs_root *root, struct btrfs_path *p)
562 struct btrfs_key key;
564 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
569 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
570 btrfs_release_path(p);
572 key.objectid += key.offset;
574 key.offset = (u64)-1;
576 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
580 * If remove is 1, then we are removing free space, thus clearing bits in the
581 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
584 static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
585 struct btrfs_block_group *block_group,
586 struct btrfs_path *path,
587 u64 start, u64 size, int remove)
589 struct btrfs_root *root = block_group->fs_info->free_space_root;
590 struct btrfs_key key;
591 u64 end = start + size;
592 u64 cur_start, cur_size;
593 int prev_bit, next_bit;
598 * Read the bit for the block immediately before the extent of space if
599 * that block is within the block group.
601 if (start > block_group->start) {
602 u64 prev_block = start - block_group->fs_info->sectorsize;
604 key.objectid = prev_block;
606 key.offset = (u64)-1;
608 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
612 prev_bit = free_space_test_bit(block_group, path, prev_block);
614 /* The previous block may have been in the previous bitmap. */
615 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
616 if (start >= key.objectid + key.offset) {
617 ret = free_space_next_bitmap(trans, root, path);
622 key.objectid = start;
624 key.offset = (u64)-1;
626 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
634 * Iterate over all of the bitmaps overlapped by the extent of space,
635 * clearing/setting bits as required.
640 free_space_set_bits(block_group, path, &cur_start, &cur_size,
644 ret = free_space_next_bitmap(trans, root, path);
650 * Read the bit for the block immediately after the extent of space if
651 * that block is within the block group.
653 if (end < block_group->start + block_group->length) {
654 /* The next block may be in the next bitmap. */
655 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
656 if (end >= key.objectid + key.offset) {
657 ret = free_space_next_bitmap(trans, root, path);
662 next_bit = free_space_test_bit(block_group, path, end);
670 /* Leftover on the left. */
674 /* Leftover on the right. */
680 /* Merging with neighbor on the left. */
684 /* Merging with neighbor on the right. */
689 btrfs_release_path(path);
690 ret = update_free_space_extent_count(trans, block_group, path,
697 static int remove_free_space_extent(struct btrfs_trans_handle *trans,
698 struct btrfs_block_group *block_group,
699 struct btrfs_path *path,
702 struct btrfs_root *root = trans->fs_info->free_space_root;
703 struct btrfs_key key;
704 u64 found_start, found_end;
705 u64 end = start + size;
706 int new_extents = -1;
709 key.objectid = start;
711 key.offset = (u64)-1;
713 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
717 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
719 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
721 found_start = key.objectid;
722 found_end = key.objectid + key.offset;
723 ASSERT(start >= found_start && end <= found_end);
726 * Okay, now that we've found the free space extent which contains the
727 * free space that we are removing, there are four cases:
729 * 1. We're using the whole extent: delete the key we found and
730 * decrement the free space extent count.
731 * 2. We are using part of the extent starting at the beginning: delete
732 * the key we found and insert a new key representing the leftover at
733 * the end. There is no net change in the number of extents.
734 * 3. We are using part of the extent ending at the end: delete the key
735 * we found and insert a new key representing the leftover at the
736 * beginning. There is no net change in the number of extents.
737 * 4. We are using part of the extent in the middle: delete the key we
738 * found and insert two new keys representing the leftovers on each
739 * side. Where we used to have one extent, we now have two, so increment
740 * the extent count. We may need to convert the block group to bitmaps
744 /* Delete the existing key (cases 1-4). */
745 ret = btrfs_del_item(trans, root, path);
749 /* Add a key for leftovers at the beginning (cases 3 and 4). */
750 if (start > found_start) {
751 key.objectid = found_start;
752 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
753 key.offset = start - found_start;
755 btrfs_release_path(path);
756 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
762 /* Add a key for leftovers at the end (cases 2 and 4). */
763 if (end < found_end) {
765 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
766 key.offset = found_end - end;
768 btrfs_release_path(path);
769 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
775 btrfs_release_path(path);
776 ret = update_free_space_extent_count(trans, block_group, path,
784 int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
785 struct btrfs_block_group *block_group,
786 struct btrfs_path *path, u64 start, u64 size)
788 struct btrfs_free_space_info *info;
792 if (block_group->needs_free_space) {
793 ret = __add_block_group_free_space(trans, block_group, path);
798 info = search_free_space_info(NULL, block_group, path, 0);
800 return PTR_ERR(info);
801 flags = btrfs_free_space_flags(path->nodes[0], info);
802 btrfs_release_path(path);
804 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
805 return modify_free_space_bitmap(trans, block_group, path,
808 return remove_free_space_extent(trans, block_group, path,
813 int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
816 struct btrfs_block_group *block_group;
817 struct btrfs_path *path;
820 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
823 path = btrfs_alloc_path();
829 block_group = btrfs_lookup_block_group(trans->fs_info, start);
836 mutex_lock(&block_group->free_space_lock);
837 ret = __remove_from_free_space_tree(trans, block_group, path, start,
839 mutex_unlock(&block_group->free_space_lock);
841 btrfs_put_block_group(block_group);
843 btrfs_free_path(path);
845 btrfs_abort_transaction(trans, ret);
849 static int add_free_space_extent(struct btrfs_trans_handle *trans,
850 struct btrfs_block_group *block_group,
851 struct btrfs_path *path,
854 struct btrfs_root *root = trans->fs_info->free_space_root;
855 struct btrfs_key key, new_key;
856 u64 found_start, found_end;
857 u64 end = start + size;
862 * We are adding a new extent of free space, but we need to merge
863 * extents. There are four cases here:
865 * 1. The new extent does not have any immediate neighbors to merge
866 * with: add the new key and increment the free space extent count. We
867 * may need to convert the block group to bitmaps as a result.
868 * 2. The new extent has an immediate neighbor before it: remove the
869 * previous key and insert a new key combining both of them. There is no
870 * net change in the number of extents.
871 * 3. The new extent has an immediate neighbor after it: remove the next
872 * key and insert a new key combining both of them. There is no net
873 * change in the number of extents.
874 * 4. The new extent has immediate neighbors on both sides: remove both
875 * of the keys and insert a new key combining all of them. Where we used
876 * to have two extents, we now have one, so decrement the extent count.
879 new_key.objectid = start;
880 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
881 new_key.offset = size;
883 /* Search for a neighbor on the left. */
884 if (start == block_group->start)
886 key.objectid = start - 1;
888 key.offset = (u64)-1;
890 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
894 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
896 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
897 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
898 btrfs_release_path(path);
902 found_start = key.objectid;
903 found_end = key.objectid + key.offset;
904 ASSERT(found_start >= block_group->start &&
905 found_end > block_group->start);
906 ASSERT(found_start < start && found_end <= start);
909 * Delete the neighbor on the left and absorb it into the new key (cases
912 if (found_end == start) {
913 ret = btrfs_del_item(trans, root, path);
916 new_key.objectid = found_start;
917 new_key.offset += key.offset;
920 btrfs_release_path(path);
923 /* Search for a neighbor on the right. */
924 if (end == block_group->start + block_group->length)
928 key.offset = (u64)-1;
930 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
934 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
936 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
937 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
938 btrfs_release_path(path);
942 found_start = key.objectid;
943 found_end = key.objectid + key.offset;
944 ASSERT(found_start >= block_group->start &&
945 found_end > block_group->start);
946 ASSERT((found_start < start && found_end <= start) ||
947 (found_start >= end && found_end > end));
950 * Delete the neighbor on the right and absorb it into the new key
953 if (found_start == end) {
954 ret = btrfs_del_item(trans, root, path);
957 new_key.offset += key.offset;
960 btrfs_release_path(path);
963 /* Insert the new key (cases 1-4). */
964 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
968 btrfs_release_path(path);
969 ret = update_free_space_extent_count(trans, block_group, path,
977 int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
978 struct btrfs_block_group *block_group,
979 struct btrfs_path *path, u64 start, u64 size)
981 struct btrfs_free_space_info *info;
985 if (block_group->needs_free_space) {
986 ret = __add_block_group_free_space(trans, block_group, path);
991 info = search_free_space_info(NULL, block_group, path, 0);
993 return PTR_ERR(info);
994 flags = btrfs_free_space_flags(path->nodes[0], info);
995 btrfs_release_path(path);
997 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
998 return modify_free_space_bitmap(trans, block_group, path,
1001 return add_free_space_extent(trans, block_group, path, start,
1006 int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1007 u64 start, u64 size)
1009 struct btrfs_block_group *block_group;
1010 struct btrfs_path *path;
1013 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1016 path = btrfs_alloc_path();
1022 block_group = btrfs_lookup_block_group(trans->fs_info, start);
1029 mutex_lock(&block_group->free_space_lock);
1030 ret = __add_to_free_space_tree(trans, block_group, path, start, size);
1031 mutex_unlock(&block_group->free_space_lock);
1033 btrfs_put_block_group(block_group);
1035 btrfs_free_path(path);
1037 btrfs_abort_transaction(trans, ret);
1042 * Populate the free space tree by walking the extent tree. Operations on the
1043 * extent tree that happen as a result of writes to the free space tree will go
1044 * through the normal add/remove hooks.
1046 static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1047 struct btrfs_block_group *block_group)
1049 struct btrfs_root *extent_root = trans->fs_info->extent_root;
1050 struct btrfs_path *path, *path2;
1051 struct btrfs_key key;
1055 path = btrfs_alloc_path();
1058 path->reada = READA_FORWARD;
1060 path2 = btrfs_alloc_path();
1062 btrfs_free_path(path);
1066 ret = add_new_free_space_info(trans, block_group, path2);
1070 mutex_lock(&block_group->free_space_lock);
1073 * Iterate through all of the extent and metadata items in this block
1074 * group, adding the free space between them and the free space at the
1075 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1076 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1079 key.objectid = block_group->start;
1080 key.type = BTRFS_EXTENT_ITEM_KEY;
1083 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1088 start = block_group->start;
1089 end = block_group->start + block_group->length;
1091 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1093 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1094 key.type == BTRFS_METADATA_ITEM_KEY) {
1095 if (key.objectid >= end)
1098 if (start < key.objectid) {
1099 ret = __add_to_free_space_tree(trans,
1107 start = key.objectid;
1108 if (key.type == BTRFS_METADATA_ITEM_KEY)
1109 start += trans->fs_info->nodesize;
1111 start += key.offset;
1112 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1113 if (key.objectid != block_group->start)
1117 ret = btrfs_next_item(extent_root, path);
1124 ret = __add_to_free_space_tree(trans, block_group, path2,
1125 start, end - start);
1132 mutex_unlock(&block_group->free_space_lock);
1134 btrfs_free_path(path2);
1135 btrfs_free_path(path);
1139 int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1141 struct btrfs_trans_handle *trans;
1142 struct btrfs_root *tree_root = fs_info->tree_root;
1143 struct btrfs_root *free_space_root;
1144 struct btrfs_block_group *block_group;
1145 struct rb_node *node;
1148 trans = btrfs_start_transaction(tree_root, 0);
1150 return PTR_ERR(trans);
1152 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1153 set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1154 free_space_root = btrfs_create_tree(trans,
1155 BTRFS_FREE_SPACE_TREE_OBJECTID);
1156 if (IS_ERR(free_space_root)) {
1157 ret = PTR_ERR(free_space_root);
1160 fs_info->free_space_root = free_space_root;
1162 node = rb_first(&fs_info->block_group_cache_tree);
1164 block_group = rb_entry(node, struct btrfs_block_group,
1166 ret = populate_free_space_tree(trans, block_group);
1169 node = rb_next(node);
1172 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1173 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1174 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1175 ret = btrfs_commit_transaction(trans);
1178 * Now that we've committed the transaction any reading of our commit
1179 * root will be safe, so we can cache from the free space tree now.
1181 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1185 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1186 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1187 btrfs_abort_transaction(trans, ret);
1188 btrfs_end_transaction(trans);
1192 static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1193 struct btrfs_root *root)
1195 struct btrfs_path *path;
1196 struct btrfs_key key;
1200 path = btrfs_alloc_path();
1209 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1213 nr = btrfs_header_nritems(path->nodes[0]);
1218 ret = btrfs_del_items(trans, root, path, 0, nr);
1222 btrfs_release_path(path);
1227 btrfs_free_path(path);
1231 int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
1233 struct btrfs_trans_handle *trans;
1234 struct btrfs_root *tree_root = fs_info->tree_root;
1235 struct btrfs_root *free_space_root = fs_info->free_space_root;
1238 trans = btrfs_start_transaction(tree_root, 0);
1240 return PTR_ERR(trans);
1242 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1243 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1244 fs_info->free_space_root = NULL;
1246 ret = clear_free_space_tree(trans, free_space_root);
1250 ret = btrfs_del_root(trans, &free_space_root->root_key);
1254 list_del(&free_space_root->dirty_list);
1256 btrfs_tree_lock(free_space_root->node);
1257 btrfs_clean_tree_block(free_space_root->node);
1258 btrfs_tree_unlock(free_space_root->node);
1259 btrfs_free_tree_block(trans, free_space_root, free_space_root->node,
1262 btrfs_put_root(free_space_root);
1264 return btrfs_commit_transaction(trans);
1267 btrfs_abort_transaction(trans, ret);
1268 btrfs_end_transaction(trans);
1272 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
1273 struct btrfs_block_group *block_group,
1274 struct btrfs_path *path)
1278 block_group->needs_free_space = 0;
1280 ret = add_new_free_space_info(trans, block_group, path);
1284 return __add_to_free_space_tree(trans, block_group, path,
1286 block_group->length);
1289 int add_block_group_free_space(struct btrfs_trans_handle *trans,
1290 struct btrfs_block_group *block_group)
1292 struct btrfs_fs_info *fs_info = trans->fs_info;
1293 struct btrfs_path *path = NULL;
1296 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1299 mutex_lock(&block_group->free_space_lock);
1300 if (!block_group->needs_free_space)
1303 path = btrfs_alloc_path();
1309 ret = __add_block_group_free_space(trans, block_group, path);
1312 btrfs_free_path(path);
1313 mutex_unlock(&block_group->free_space_lock);
1315 btrfs_abort_transaction(trans, ret);
1319 int remove_block_group_free_space(struct btrfs_trans_handle *trans,
1320 struct btrfs_block_group *block_group)
1322 struct btrfs_root *root = trans->fs_info->free_space_root;
1323 struct btrfs_path *path;
1324 struct btrfs_key key, found_key;
1325 struct extent_buffer *leaf;
1330 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1333 if (block_group->needs_free_space) {
1334 /* We never added this block group to the free space tree. */
1338 path = btrfs_alloc_path();
1344 start = block_group->start;
1345 end = block_group->start + block_group->length;
1347 key.objectid = end - 1;
1349 key.offset = (u64)-1;
1352 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1356 leaf = path->nodes[0];
1359 while (path->slots[0] > 0) {
1360 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1362 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
1363 ASSERT(found_key.objectid == block_group->start);
1364 ASSERT(found_key.offset == block_group->length);
1369 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY ||
1370 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
1371 ASSERT(found_key.objectid >= start);
1372 ASSERT(found_key.objectid < end);
1373 ASSERT(found_key.objectid + found_key.offset <= end);
1381 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1384 btrfs_release_path(path);
1389 btrfs_free_path(path);
1391 btrfs_abort_transaction(trans, ret);
1395 static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1396 struct btrfs_path *path,
1397 u32 expected_extent_count)
1399 struct btrfs_block_group *block_group;
1400 struct btrfs_fs_info *fs_info;
1401 struct btrfs_root *root;
1402 struct btrfs_key key;
1403 int prev_bit = 0, bit;
1404 /* Initialize to silence GCC. */
1405 u64 extent_start = 0;
1407 u64 total_found = 0;
1408 u32 extent_count = 0;
1411 block_group = caching_ctl->block_group;
1412 fs_info = block_group->fs_info;
1413 root = fs_info->free_space_root;
1415 end = block_group->start + block_group->length;
1418 ret = btrfs_next_item(root, path);
1424 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1426 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1429 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1430 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1432 caching_ctl->progress = key.objectid;
1434 offset = key.objectid;
1435 while (offset < key.objectid + key.offset) {
1436 bit = free_space_test_bit(block_group, path, offset);
1437 if (prev_bit == 0 && bit == 1) {
1438 extent_start = offset;
1439 } else if (prev_bit == 1 && bit == 0) {
1440 total_found += add_new_free_space(block_group,
1443 if (total_found > CACHING_CTL_WAKE_UP) {
1445 wake_up(&caching_ctl->wait);
1450 offset += fs_info->sectorsize;
1453 if (prev_bit == 1) {
1454 total_found += add_new_free_space(block_group, extent_start,
1459 if (extent_count != expected_extent_count) {
1461 "incorrect extent count for %llu; counted %u, expected %u",
1462 block_group->start, extent_count,
1463 expected_extent_count);
1469 caching_ctl->progress = (u64)-1;
1476 static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1477 struct btrfs_path *path,
1478 u32 expected_extent_count)
1480 struct btrfs_block_group *block_group;
1481 struct btrfs_fs_info *fs_info;
1482 struct btrfs_root *root;
1483 struct btrfs_key key;
1485 u64 total_found = 0;
1486 u32 extent_count = 0;
1489 block_group = caching_ctl->block_group;
1490 fs_info = block_group->fs_info;
1491 root = fs_info->free_space_root;
1493 end = block_group->start + block_group->length;
1496 ret = btrfs_next_item(root, path);
1502 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1504 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1507 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1508 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1510 caching_ctl->progress = key.objectid;
1512 total_found += add_new_free_space(block_group, key.objectid,
1513 key.objectid + key.offset);
1514 if (total_found > CACHING_CTL_WAKE_UP) {
1516 wake_up(&caching_ctl->wait);
1521 if (extent_count != expected_extent_count) {
1523 "incorrect extent count for %llu; counted %u, expected %u",
1524 block_group->start, extent_count,
1525 expected_extent_count);
1531 caching_ctl->progress = (u64)-1;
1538 int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
1540 struct btrfs_block_group *block_group;
1541 struct btrfs_free_space_info *info;
1542 struct btrfs_path *path;
1543 u32 extent_count, flags;
1546 block_group = caching_ctl->block_group;
1548 path = btrfs_alloc_path();
1553 * Just like caching_thread() doesn't want to deadlock on the extent
1554 * tree, we don't want to deadlock on the free space tree.
1556 path->skip_locking = 1;
1557 path->search_commit_root = 1;
1558 path->reada = READA_FORWARD;
1560 info = search_free_space_info(NULL, block_group, path, 0);
1562 ret = PTR_ERR(info);
1565 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
1566 flags = btrfs_free_space_flags(path->nodes[0], info);
1569 * We left path pointing to the free space info item, so now
1570 * load_free_space_foo can just iterate through the free space tree from
1573 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS)
1574 ret = load_free_space_bitmaps(caching_ctl, path, extent_count);
1576 ret = load_free_space_extents(caching_ctl, path, extent_count);
1579 btrfs_free_path(path);