2 * Copyright (C) 2015 Facebook. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/kernel.h>
20 #include <linux/vmalloc.h>
24 #include "free-space-tree.h"
25 #include "transaction.h"
28 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
29 struct btrfs_fs_info *fs_info,
30 struct btrfs_block_group_cache *block_group,
31 struct btrfs_path *path);
33 void set_free_space_tree_thresholds(struct btrfs_block_group_cache *cache)
37 u64 num_bitmaps, total_bitmap_size;
40 * We convert to bitmaps when the disk space required for using extents
41 * exceeds that required for using bitmaps.
43 bitmap_range = cache->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
44 num_bitmaps = div_u64(cache->key.offset + bitmap_range - 1,
46 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
47 total_bitmap_size = num_bitmaps * bitmap_size;
48 cache->bitmap_high_thresh = div_u64(total_bitmap_size,
49 sizeof(struct btrfs_item));
52 * We allow for a small buffer between the high threshold and low
53 * threshold to avoid thrashing back and forth between the two formats.
55 if (cache->bitmap_high_thresh > 100)
56 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
58 cache->bitmap_low_thresh = 0;
61 static int add_new_free_space_info(struct btrfs_trans_handle *trans,
62 struct btrfs_fs_info *fs_info,
63 struct btrfs_block_group_cache *block_group,
64 struct btrfs_path *path)
66 struct btrfs_root *root = fs_info->free_space_root;
67 struct btrfs_free_space_info *info;
69 struct extent_buffer *leaf;
72 key.objectid = block_group->key.objectid;
73 key.type = BTRFS_FREE_SPACE_INFO_KEY;
74 key.offset = block_group->key.offset;
76 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
80 leaf = path->nodes[0];
81 info = btrfs_item_ptr(leaf, path->slots[0],
82 struct btrfs_free_space_info);
83 btrfs_set_free_space_extent_count(leaf, info, 0);
84 btrfs_set_free_space_flags(leaf, info, 0);
85 btrfs_mark_buffer_dirty(leaf);
89 btrfs_release_path(path);
93 struct btrfs_free_space_info *
94 search_free_space_info(struct btrfs_trans_handle *trans,
95 struct btrfs_fs_info *fs_info,
96 struct btrfs_block_group_cache *block_group,
97 struct btrfs_path *path, int cow)
99 struct btrfs_root *root = fs_info->free_space_root;
100 struct btrfs_key key;
103 key.objectid = block_group->key.objectid;
104 key.type = BTRFS_FREE_SPACE_INFO_KEY;
105 key.offset = block_group->key.offset;
107 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
111 btrfs_warn(fs_info, "missing free space info for %llu\n",
112 block_group->key.objectid);
114 return ERR_PTR(-ENOENT);
117 return btrfs_item_ptr(path->nodes[0], path->slots[0],
118 struct btrfs_free_space_info);
122 * btrfs_search_slot() but we're looking for the greatest key less than the
125 static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
126 struct btrfs_root *root,
127 struct btrfs_key *key, struct btrfs_path *p,
128 int ins_len, int cow)
132 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
141 if (p->slots[0] == 0) {
150 static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize)
152 return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
155 static unsigned long *alloc_bitmap(u32 bitmap_size)
160 * The allocation size varies, observed numbers were < 4K up to 16K.
161 * Using vmalloc unconditionally would be too heavy, we'll try
162 * contiguous allocations first.
164 if (bitmap_size <= PAGE_SIZE)
165 return kzalloc(bitmap_size, GFP_NOFS);
167 mem = kzalloc(bitmap_size, GFP_NOFS | __GFP_NOWARN);
171 return __vmalloc(bitmap_size, GFP_NOFS | __GFP_HIGHMEM | __GFP_ZERO,
175 int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
176 struct btrfs_fs_info *fs_info,
177 struct btrfs_block_group_cache *block_group,
178 struct btrfs_path *path)
180 struct btrfs_root *root = fs_info->free_space_root;
181 struct btrfs_free_space_info *info;
182 struct btrfs_key key, found_key;
183 struct extent_buffer *leaf;
184 unsigned long *bitmap;
188 u32 bitmap_size, flags, expected_extent_count;
189 u32 extent_count = 0;
193 bitmap_size = free_space_bitmap_size(block_group->key.offset,
194 block_group->sectorsize);
195 bitmap = alloc_bitmap(bitmap_size);
201 start = block_group->key.objectid;
202 end = block_group->key.objectid + block_group->key.offset;
204 key.objectid = end - 1;
206 key.offset = (u64)-1;
209 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
213 leaf = path->nodes[0];
216 while (path->slots[0] > 0) {
217 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
219 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
220 ASSERT(found_key.objectid == block_group->key.objectid);
221 ASSERT(found_key.offset == block_group->key.offset);
224 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
227 ASSERT(found_key.objectid >= start);
228 ASSERT(found_key.objectid < end);
229 ASSERT(found_key.objectid + found_key.offset <= end);
231 first = div_u64(found_key.objectid - start,
232 block_group->sectorsize);
233 last = div_u64(found_key.objectid + found_key.offset - start,
234 block_group->sectorsize);
235 bitmap_set(bitmap, first, last - first);
245 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
248 btrfs_release_path(path);
251 info = search_free_space_info(trans, fs_info, block_group, path, 1);
256 leaf = path->nodes[0];
257 flags = btrfs_free_space_flags(leaf, info);
258 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
259 btrfs_set_free_space_flags(leaf, info, flags);
260 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
261 btrfs_mark_buffer_dirty(leaf);
262 btrfs_release_path(path);
264 if (extent_count != expected_extent_count) {
265 btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u",
266 block_group->key.objectid, extent_count,
267 expected_extent_count);
273 bitmap_cursor = (char *)bitmap;
274 bitmap_range = block_group->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
281 extent_size = min(end - i, bitmap_range);
282 data_size = free_space_bitmap_size(extent_size,
283 block_group->sectorsize);
286 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
287 key.offset = extent_size;
289 ret = btrfs_insert_empty_item(trans, root, path, &key,
294 leaf = path->nodes[0];
295 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
296 write_extent_buffer(leaf, bitmap_cursor, ptr,
298 btrfs_mark_buffer_dirty(leaf);
299 btrfs_release_path(path);
302 bitmap_cursor += data_size;
309 btrfs_abort_transaction(trans, root, ret);
313 int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
314 struct btrfs_fs_info *fs_info,
315 struct btrfs_block_group_cache *block_group,
316 struct btrfs_path *path)
318 struct btrfs_root *root = fs_info->free_space_root;
319 struct btrfs_free_space_info *info;
320 struct btrfs_key key, found_key;
321 struct extent_buffer *leaf;
322 unsigned long *bitmap;
324 /* Initialize to silence GCC. */
325 u64 extent_start = 0;
327 u32 bitmap_size, flags, expected_extent_count;
328 int prev_bit = 0, bit, bitnr;
329 u32 extent_count = 0;
333 bitmap_size = free_space_bitmap_size(block_group->key.offset,
334 block_group->sectorsize);
335 bitmap = alloc_bitmap(bitmap_size);
341 start = block_group->key.objectid;
342 end = block_group->key.objectid + block_group->key.offset;
344 key.objectid = end - 1;
346 key.offset = (u64)-1;
349 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
353 leaf = path->nodes[0];
356 while (path->slots[0] > 0) {
357 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
359 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
360 ASSERT(found_key.objectid == block_group->key.objectid);
361 ASSERT(found_key.offset == block_group->key.offset);
364 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
367 u32 bitmap_pos, data_size;
369 ASSERT(found_key.objectid >= start);
370 ASSERT(found_key.objectid < end);
371 ASSERT(found_key.objectid + found_key.offset <= end);
373 bitmap_pos = div_u64(found_key.objectid - start,
374 block_group->sectorsize *
376 bitmap_cursor = ((char *)bitmap) + bitmap_pos;
377 data_size = free_space_bitmap_size(found_key.offset,
378 block_group->sectorsize);
380 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
381 read_extent_buffer(leaf, bitmap_cursor, ptr,
391 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
394 btrfs_release_path(path);
397 info = search_free_space_info(trans, fs_info, block_group, path, 1);
402 leaf = path->nodes[0];
403 flags = btrfs_free_space_flags(leaf, info);
404 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
405 btrfs_set_free_space_flags(leaf, info, flags);
406 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
407 btrfs_mark_buffer_dirty(leaf);
408 btrfs_release_path(path);
412 while (offset < end) {
413 bit = !!test_bit(bitnr, bitmap);
414 if (prev_bit == 0 && bit == 1) {
415 extent_start = offset;
416 } else if (prev_bit == 1 && bit == 0) {
417 key.objectid = extent_start;
418 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
419 key.offset = offset - extent_start;
421 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
424 btrfs_release_path(path);
429 offset += block_group->sectorsize;
433 key.objectid = extent_start;
434 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
435 key.offset = end - extent_start;
437 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
440 btrfs_release_path(path);
445 if (extent_count != expected_extent_count) {
446 btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u",
447 block_group->key.objectid, extent_count,
448 expected_extent_count);
458 btrfs_abort_transaction(trans, root, ret);
462 static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
463 struct btrfs_fs_info *fs_info,
464 struct btrfs_block_group_cache *block_group,
465 struct btrfs_path *path,
468 struct btrfs_free_space_info *info;
473 if (new_extents == 0)
476 info = search_free_space_info(trans, fs_info, block_group, path, 1);
481 flags = btrfs_free_space_flags(path->nodes[0], info);
482 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
484 extent_count += new_extents;
485 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
486 btrfs_mark_buffer_dirty(path->nodes[0]);
487 btrfs_release_path(path);
489 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
490 extent_count > block_group->bitmap_high_thresh) {
491 ret = convert_free_space_to_bitmaps(trans, fs_info, block_group,
493 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
494 extent_count < block_group->bitmap_low_thresh) {
495 ret = convert_free_space_to_extents(trans, fs_info, block_group,
503 int free_space_test_bit(struct btrfs_block_group_cache *block_group,
504 struct btrfs_path *path, u64 offset)
506 struct extent_buffer *leaf;
507 struct btrfs_key key;
508 u64 found_start, found_end;
509 unsigned long ptr, i;
511 leaf = path->nodes[0];
512 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
513 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
515 found_start = key.objectid;
516 found_end = key.objectid + key.offset;
517 ASSERT(offset >= found_start && offset < found_end);
519 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
520 i = div_u64(offset - found_start, block_group->sectorsize);
521 return !!extent_buffer_test_bit(leaf, ptr, i);
524 static void free_space_set_bits(struct btrfs_block_group_cache *block_group,
525 struct btrfs_path *path, u64 *start, u64 *size,
528 struct extent_buffer *leaf;
529 struct btrfs_key key;
530 u64 end = *start + *size;
531 u64 found_start, found_end;
532 unsigned long ptr, first, last;
534 leaf = path->nodes[0];
535 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
536 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
538 found_start = key.objectid;
539 found_end = key.objectid + key.offset;
540 ASSERT(*start >= found_start && *start < found_end);
541 ASSERT(end > found_start);
546 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
547 first = div_u64(*start - found_start, block_group->sectorsize);
548 last = div_u64(end - found_start, block_group->sectorsize);
550 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
552 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
553 btrfs_mark_buffer_dirty(leaf);
555 *size -= end - *start;
560 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
561 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
562 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
565 static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
566 struct btrfs_root *root, struct btrfs_path *p)
568 struct btrfs_key key;
570 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
575 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
576 btrfs_release_path(p);
578 key.objectid += key.offset;
580 key.offset = (u64)-1;
582 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
586 * If remove is 1, then we are removing free space, thus clearing bits in the
587 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
590 static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
591 struct btrfs_fs_info *fs_info,
592 struct btrfs_block_group_cache *block_group,
593 struct btrfs_path *path,
594 u64 start, u64 size, int remove)
596 struct btrfs_root *root = fs_info->free_space_root;
597 struct btrfs_key key;
598 u64 end = start + size;
599 u64 cur_start, cur_size;
600 int prev_bit, next_bit;
605 * Read the bit for the block immediately before the extent of space if
606 * that block is within the block group.
608 if (start > block_group->key.objectid) {
609 u64 prev_block = start - block_group->sectorsize;
611 key.objectid = prev_block;
613 key.offset = (u64)-1;
615 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
619 prev_bit = free_space_test_bit(block_group, path, prev_block);
621 /* The previous block may have been in the previous bitmap. */
622 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
623 if (start >= key.objectid + key.offset) {
624 ret = free_space_next_bitmap(trans, root, path);
629 key.objectid = start;
631 key.offset = (u64)-1;
633 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
641 * Iterate over all of the bitmaps overlapped by the extent of space,
642 * clearing/setting bits as required.
647 free_space_set_bits(block_group, path, &cur_start, &cur_size,
651 ret = free_space_next_bitmap(trans, root, path);
657 * Read the bit for the block immediately after the extent of space if
658 * that block is within the block group.
660 if (end < block_group->key.objectid + block_group->key.offset) {
661 /* The next block may be in the next bitmap. */
662 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
663 if (end >= key.objectid + key.offset) {
664 ret = free_space_next_bitmap(trans, root, path);
669 next_bit = free_space_test_bit(block_group, path, end);
677 /* Leftover on the left. */
681 /* Leftover on the right. */
687 /* Merging with neighbor on the left. */
691 /* Merging with neighbor on the right. */
696 btrfs_release_path(path);
697 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
704 static int remove_free_space_extent(struct btrfs_trans_handle *trans,
705 struct btrfs_fs_info *fs_info,
706 struct btrfs_block_group_cache *block_group,
707 struct btrfs_path *path,
710 struct btrfs_root *root = fs_info->free_space_root;
711 struct btrfs_key key;
712 u64 found_start, found_end;
713 u64 end = start + size;
714 int new_extents = -1;
717 key.objectid = start;
719 key.offset = (u64)-1;
721 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
725 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
727 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
729 found_start = key.objectid;
730 found_end = key.objectid + key.offset;
731 ASSERT(start >= found_start && end <= found_end);
734 * Okay, now that we've found the free space extent which contains the
735 * free space that we are removing, there are four cases:
737 * 1. We're using the whole extent: delete the key we found and
738 * decrement the free space extent count.
739 * 2. We are using part of the extent starting at the beginning: delete
740 * the key we found and insert a new key representing the leftover at
741 * the end. There is no net change in the number of extents.
742 * 3. We are using part of the extent ending at the end: delete the key
743 * we found and insert a new key representing the leftover at the
744 * beginning. There is no net change in the number of extents.
745 * 4. We are using part of the extent in the middle: delete the key we
746 * found and insert two new keys representing the leftovers on each
747 * side. Where we used to have one extent, we now have two, so increment
748 * the extent count. We may need to convert the block group to bitmaps
752 /* Delete the existing key (cases 1-4). */
753 ret = btrfs_del_item(trans, root, path);
757 /* Add a key for leftovers at the beginning (cases 3 and 4). */
758 if (start > found_start) {
759 key.objectid = found_start;
760 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
761 key.offset = start - found_start;
763 btrfs_release_path(path);
764 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
770 /* Add a key for leftovers at the end (cases 2 and 4). */
771 if (end < found_end) {
773 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
774 key.offset = found_end - end;
776 btrfs_release_path(path);
777 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
783 btrfs_release_path(path);
784 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
791 int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
792 struct btrfs_fs_info *fs_info,
793 struct btrfs_block_group_cache *block_group,
794 struct btrfs_path *path, u64 start, u64 size)
796 struct btrfs_free_space_info *info;
800 if (block_group->needs_free_space) {
801 ret = __add_block_group_free_space(trans, fs_info, block_group,
807 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
809 return PTR_ERR(info);
810 flags = btrfs_free_space_flags(path->nodes[0], info);
811 btrfs_release_path(path);
813 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
814 return modify_free_space_bitmap(trans, fs_info, block_group,
815 path, start, size, 1);
817 return remove_free_space_extent(trans, fs_info, block_group,
822 int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
823 struct btrfs_fs_info *fs_info,
826 struct btrfs_block_group_cache *block_group;
827 struct btrfs_path *path;
830 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
833 path = btrfs_alloc_path();
839 block_group = btrfs_lookup_block_group(fs_info, start);
846 mutex_lock(&block_group->free_space_lock);
847 ret = __remove_from_free_space_tree(trans, fs_info, block_group, path,
849 mutex_unlock(&block_group->free_space_lock);
851 btrfs_put_block_group(block_group);
853 btrfs_free_path(path);
855 btrfs_abort_transaction(trans, fs_info->free_space_root, ret);
859 static int add_free_space_extent(struct btrfs_trans_handle *trans,
860 struct btrfs_fs_info *fs_info,
861 struct btrfs_block_group_cache *block_group,
862 struct btrfs_path *path,
865 struct btrfs_root *root = fs_info->free_space_root;
866 struct btrfs_key key, new_key;
867 u64 found_start, found_end;
868 u64 end = start + size;
873 * We are adding a new extent of free space, but we need to merge
874 * extents. There are four cases here:
876 * 1. The new extent does not have any immediate neighbors to merge
877 * with: add the new key and increment the free space extent count. We
878 * may need to convert the block group to bitmaps as a result.
879 * 2. The new extent has an immediate neighbor before it: remove the
880 * previous key and insert a new key combining both of them. There is no
881 * net change in the number of extents.
882 * 3. The new extent has an immediate neighbor after it: remove the next
883 * key and insert a new key combining both of them. There is no net
884 * change in the number of extents.
885 * 4. The new extent has immediate neighbors on both sides: remove both
886 * of the keys and insert a new key combining all of them. Where we used
887 * to have two extents, we now have one, so decrement the extent count.
890 new_key.objectid = start;
891 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
892 new_key.offset = size;
894 /* Search for a neighbor on the left. */
895 if (start == block_group->key.objectid)
897 key.objectid = start - 1;
899 key.offset = (u64)-1;
901 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
905 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
907 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
908 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
909 btrfs_release_path(path);
913 found_start = key.objectid;
914 found_end = key.objectid + key.offset;
915 ASSERT(found_start >= block_group->key.objectid &&
916 found_end > block_group->key.objectid);
917 ASSERT(found_start < start && found_end <= start);
920 * Delete the neighbor on the left and absorb it into the new key (cases
923 if (found_end == start) {
924 ret = btrfs_del_item(trans, root, path);
927 new_key.objectid = found_start;
928 new_key.offset += key.offset;
931 btrfs_release_path(path);
934 /* Search for a neighbor on the right. */
935 if (end == block_group->key.objectid + block_group->key.offset)
939 key.offset = (u64)-1;
941 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
945 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
947 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
948 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
949 btrfs_release_path(path);
953 found_start = key.objectid;
954 found_end = key.objectid + key.offset;
955 ASSERT(found_start >= block_group->key.objectid &&
956 found_end > block_group->key.objectid);
957 ASSERT((found_start < start && found_end <= start) ||
958 (found_start >= end && found_end > end));
961 * Delete the neighbor on the right and absorb it into the new key
964 if (found_start == end) {
965 ret = btrfs_del_item(trans, root, path);
968 new_key.offset += key.offset;
971 btrfs_release_path(path);
974 /* Insert the new key (cases 1-4). */
975 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
979 btrfs_release_path(path);
980 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
987 int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
988 struct btrfs_fs_info *fs_info,
989 struct btrfs_block_group_cache *block_group,
990 struct btrfs_path *path, u64 start, u64 size)
992 struct btrfs_free_space_info *info;
996 if (block_group->needs_free_space) {
997 ret = __add_block_group_free_space(trans, fs_info, block_group,
1003 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
1005 return PTR_ERR(info);
1006 flags = btrfs_free_space_flags(path->nodes[0], info);
1007 btrfs_release_path(path);
1009 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
1010 return modify_free_space_bitmap(trans, fs_info, block_group,
1011 path, start, size, 0);
1013 return add_free_space_extent(trans, fs_info, block_group, path,
1018 int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1019 struct btrfs_fs_info *fs_info,
1020 u64 start, u64 size)
1022 struct btrfs_block_group_cache *block_group;
1023 struct btrfs_path *path;
1026 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1029 path = btrfs_alloc_path();
1035 block_group = btrfs_lookup_block_group(fs_info, start);
1042 mutex_lock(&block_group->free_space_lock);
1043 ret = __add_to_free_space_tree(trans, fs_info, block_group, path, start,
1045 mutex_unlock(&block_group->free_space_lock);
1047 btrfs_put_block_group(block_group);
1049 btrfs_free_path(path);
1051 btrfs_abort_transaction(trans, fs_info->free_space_root, ret);
1056 * Populate the free space tree by walking the extent tree. Operations on the
1057 * extent tree that happen as a result of writes to the free space tree will go
1058 * through the normal add/remove hooks.
1060 static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1061 struct btrfs_fs_info *fs_info,
1062 struct btrfs_block_group_cache *block_group)
1064 struct btrfs_root *extent_root = fs_info->extent_root;
1065 struct btrfs_path *path, *path2;
1066 struct btrfs_key key;
1070 path = btrfs_alloc_path();
1075 path2 = btrfs_alloc_path();
1077 btrfs_free_path(path);
1081 ret = add_new_free_space_info(trans, fs_info, block_group, path2);
1085 mutex_lock(&block_group->free_space_lock);
1088 * Iterate through all of the extent and metadata items in this block
1089 * group, adding the free space between them and the free space at the
1090 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1091 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1094 key.objectid = block_group->key.objectid;
1095 key.type = BTRFS_EXTENT_ITEM_KEY;
1098 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1103 start = block_group->key.objectid;
1104 end = block_group->key.objectid + block_group->key.offset;
1106 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1108 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1109 key.type == BTRFS_METADATA_ITEM_KEY) {
1110 if (key.objectid >= end)
1113 if (start < key.objectid) {
1114 ret = __add_to_free_space_tree(trans, fs_info,
1122 start = key.objectid;
1123 if (key.type == BTRFS_METADATA_ITEM_KEY)
1124 start += fs_info->tree_root->nodesize;
1126 start += key.offset;
1127 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1128 if (key.objectid != block_group->key.objectid)
1132 ret = btrfs_next_item(extent_root, path);
1139 ret = __add_to_free_space_tree(trans, fs_info, block_group,
1140 path2, start, end - start);
1147 mutex_unlock(&block_group->free_space_lock);
1149 btrfs_free_path(path2);
1150 btrfs_free_path(path);
1154 int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1156 struct btrfs_trans_handle *trans;
1157 struct btrfs_root *tree_root = fs_info->tree_root;
1158 struct btrfs_root *free_space_root;
1159 struct btrfs_block_group_cache *block_group;
1160 struct rb_node *node;
1163 trans = btrfs_start_transaction(tree_root, 0);
1165 return PTR_ERR(trans);
1167 fs_info->creating_free_space_tree = 1;
1168 free_space_root = btrfs_create_tree(trans, fs_info,
1169 BTRFS_FREE_SPACE_TREE_OBJECTID);
1170 if (IS_ERR(free_space_root)) {
1171 ret = PTR_ERR(free_space_root);
1174 fs_info->free_space_root = free_space_root;
1176 node = rb_first(&fs_info->block_group_cache_tree);
1178 block_group = rb_entry(node, struct btrfs_block_group_cache,
1180 ret = populate_free_space_tree(trans, fs_info, block_group);
1183 node = rb_next(node);
1186 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1187 btrfs_sysfs_feature_update(fs_info,
1188 BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE, FEAT_COMPAT_RO);
1190 fs_info->creating_free_space_tree = 0;
1192 ret = btrfs_commit_transaction(trans, tree_root);
1199 fs_info->creating_free_space_tree = 0;
1200 btrfs_abort_transaction(trans, tree_root, ret);
1201 btrfs_end_transaction(trans, tree_root);
1205 static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1206 struct btrfs_root *root)
1208 struct btrfs_path *path;
1209 struct btrfs_key key;
1213 path = btrfs_alloc_path();
1217 path->leave_spinning = 1;
1224 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1228 nr = btrfs_header_nritems(path->nodes[0]);
1233 ret = btrfs_del_items(trans, root, path, 0, nr);
1237 btrfs_release_path(path);
1242 btrfs_free_path(path);
1246 int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
1248 struct btrfs_trans_handle *trans;
1249 struct btrfs_root *tree_root = fs_info->tree_root;
1250 struct btrfs_root *free_space_root = fs_info->free_space_root;
1253 trans = btrfs_start_transaction(tree_root, 0);
1255 return PTR_ERR(trans);
1257 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1258 btrfs_sysfs_feature_update(fs_info,
1259 BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE, FEAT_COMPAT_RO);
1261 fs_info->free_space_root = NULL;
1263 ret = clear_free_space_tree(trans, free_space_root);
1267 ret = btrfs_del_root(trans, tree_root, &free_space_root->root_key);
1271 list_del(&free_space_root->dirty_list);
1273 btrfs_tree_lock(free_space_root->node);
1274 clean_tree_block(trans, tree_root->fs_info, free_space_root->node);
1275 btrfs_tree_unlock(free_space_root->node);
1276 btrfs_free_tree_block(trans, free_space_root, free_space_root->node,
1279 free_extent_buffer(free_space_root->node);
1280 free_extent_buffer(free_space_root->commit_root);
1281 kfree(free_space_root);
1283 ret = btrfs_commit_transaction(trans, tree_root);
1290 btrfs_abort_transaction(trans, tree_root, ret);
1291 btrfs_end_transaction(trans, tree_root);
1295 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
1296 struct btrfs_fs_info *fs_info,
1297 struct btrfs_block_group_cache *block_group,
1298 struct btrfs_path *path)
1303 start = block_group->key.objectid;
1304 end = block_group->key.objectid + block_group->key.offset;
1306 block_group->needs_free_space = 0;
1308 ret = add_new_free_space_info(trans, fs_info, block_group, path);
1312 return __add_to_free_space_tree(trans, fs_info, block_group, path,
1313 block_group->key.objectid,
1314 block_group->key.offset);
1317 int add_block_group_free_space(struct btrfs_trans_handle *trans,
1318 struct btrfs_fs_info *fs_info,
1319 struct btrfs_block_group_cache *block_group)
1321 struct btrfs_path *path = NULL;
1324 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1327 mutex_lock(&block_group->free_space_lock);
1328 if (!block_group->needs_free_space)
1331 path = btrfs_alloc_path();
1337 ret = __add_block_group_free_space(trans, fs_info, block_group, path);
1340 btrfs_free_path(path);
1341 mutex_unlock(&block_group->free_space_lock);
1343 btrfs_abort_transaction(trans, fs_info->free_space_root, ret);
1347 int remove_block_group_free_space(struct btrfs_trans_handle *trans,
1348 struct btrfs_fs_info *fs_info,
1349 struct btrfs_block_group_cache *block_group)
1351 struct btrfs_root *root = fs_info->free_space_root;
1352 struct btrfs_path *path;
1353 struct btrfs_key key, found_key;
1354 struct extent_buffer *leaf;
1359 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1362 if (block_group->needs_free_space) {
1363 /* We never added this block group to the free space tree. */
1367 path = btrfs_alloc_path();
1373 start = block_group->key.objectid;
1374 end = block_group->key.objectid + block_group->key.offset;
1376 key.objectid = end - 1;
1378 key.offset = (u64)-1;
1381 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1385 leaf = path->nodes[0];
1388 while (path->slots[0] > 0) {
1389 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1391 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
1392 ASSERT(found_key.objectid == block_group->key.objectid);
1393 ASSERT(found_key.offset == block_group->key.offset);
1398 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY ||
1399 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
1400 ASSERT(found_key.objectid >= start);
1401 ASSERT(found_key.objectid < end);
1402 ASSERT(found_key.objectid + found_key.offset <= end);
1410 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1413 btrfs_release_path(path);
1418 btrfs_free_path(path);
1420 btrfs_abort_transaction(trans, root, ret);
1424 static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1425 struct btrfs_path *path,
1426 u32 expected_extent_count)
1428 struct btrfs_block_group_cache *block_group;
1429 struct btrfs_fs_info *fs_info;
1430 struct btrfs_root *root;
1431 struct btrfs_key key;
1432 int prev_bit = 0, bit;
1433 /* Initialize to silence GCC. */
1434 u64 extent_start = 0;
1436 u64 total_found = 0;
1437 u32 extent_count = 0;
1440 block_group = caching_ctl->block_group;
1441 fs_info = block_group->fs_info;
1442 root = fs_info->free_space_root;
1444 end = block_group->key.objectid + block_group->key.offset;
1447 ret = btrfs_next_item(root, path);
1453 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1455 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1458 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1459 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1461 caching_ctl->progress = key.objectid;
1463 offset = key.objectid;
1464 while (offset < key.objectid + key.offset) {
1465 bit = free_space_test_bit(block_group, path, offset);
1466 if (prev_bit == 0 && bit == 1) {
1467 extent_start = offset;
1468 } else if (prev_bit == 1 && bit == 0) {
1469 total_found += add_new_free_space(block_group,
1473 if (total_found > CACHING_CTL_WAKE_UP) {
1475 wake_up(&caching_ctl->wait);
1480 offset += block_group->sectorsize;
1483 if (prev_bit == 1) {
1484 total_found += add_new_free_space(block_group, fs_info,
1489 if (extent_count != expected_extent_count) {
1490 btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u",
1491 block_group->key.objectid, extent_count,
1492 expected_extent_count);
1498 caching_ctl->progress = (u64)-1;
1505 static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1506 struct btrfs_path *path,
1507 u32 expected_extent_count)
1509 struct btrfs_block_group_cache *block_group;
1510 struct btrfs_fs_info *fs_info;
1511 struct btrfs_root *root;
1512 struct btrfs_key key;
1514 u64 total_found = 0;
1515 u32 extent_count = 0;
1518 block_group = caching_ctl->block_group;
1519 fs_info = block_group->fs_info;
1520 root = fs_info->free_space_root;
1522 end = block_group->key.objectid + block_group->key.offset;
1525 ret = btrfs_next_item(root, path);
1531 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1533 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1536 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1537 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1539 caching_ctl->progress = key.objectid;
1541 total_found += add_new_free_space(block_group, fs_info,
1543 key.objectid + key.offset);
1544 if (total_found > CACHING_CTL_WAKE_UP) {
1546 wake_up(&caching_ctl->wait);
1551 if (extent_count != expected_extent_count) {
1552 btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u",
1553 block_group->key.objectid, extent_count,
1554 expected_extent_count);
1560 caching_ctl->progress = (u64)-1;
1567 int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
1569 struct btrfs_block_group_cache *block_group;
1570 struct btrfs_fs_info *fs_info;
1571 struct btrfs_free_space_info *info;
1572 struct btrfs_path *path;
1573 u32 extent_count, flags;
1576 block_group = caching_ctl->block_group;
1577 fs_info = block_group->fs_info;
1579 path = btrfs_alloc_path();
1584 * Just like caching_thread() doesn't want to deadlock on the extent
1585 * tree, we don't want to deadlock on the free space tree.
1587 path->skip_locking = 1;
1588 path->search_commit_root = 1;
1591 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
1593 ret = PTR_ERR(info);
1596 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
1597 flags = btrfs_free_space_flags(path->nodes[0], info);
1600 * We left path pointing to the free space info item, so now
1601 * load_free_space_foo can just iterate through the free space tree from
1604 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS)
1605 ret = load_free_space_bitmaps(caching_ctl, path, extent_count);
1607 ret = load_free_space_extents(caching_ctl, path, extent_count);
1610 btrfs_free_path(path);