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"
27 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
28 struct btrfs_fs_info *fs_info,
29 struct btrfs_block_group_cache *block_group,
30 struct btrfs_path *path);
32 void set_free_space_tree_thresholds(struct btrfs_block_group_cache *cache)
36 u64 num_bitmaps, total_bitmap_size;
39 * We convert to bitmaps when the disk space required for using extents
40 * exceeds that required for using bitmaps.
42 bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
43 num_bitmaps = div_u64(cache->key.offset + bitmap_range - 1,
45 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
46 total_bitmap_size = num_bitmaps * bitmap_size;
47 cache->bitmap_high_thresh = div_u64(total_bitmap_size,
48 sizeof(struct btrfs_item));
51 * We allow for a small buffer between the high threshold and low
52 * threshold to avoid thrashing back and forth between the two formats.
54 if (cache->bitmap_high_thresh > 100)
55 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
57 cache->bitmap_low_thresh = 0;
60 static int add_new_free_space_info(struct btrfs_trans_handle *trans,
61 struct btrfs_fs_info *fs_info,
62 struct btrfs_block_group_cache *block_group,
63 struct btrfs_path *path)
65 struct btrfs_root *root = fs_info->free_space_root;
66 struct btrfs_free_space_info *info;
68 struct extent_buffer *leaf;
71 key.objectid = block_group->key.objectid;
72 key.type = BTRFS_FREE_SPACE_INFO_KEY;
73 key.offset = block_group->key.offset;
75 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
79 leaf = path->nodes[0];
80 info = btrfs_item_ptr(leaf, path->slots[0],
81 struct btrfs_free_space_info);
82 btrfs_set_free_space_extent_count(leaf, info, 0);
83 btrfs_set_free_space_flags(leaf, info, 0);
84 btrfs_mark_buffer_dirty(leaf);
88 btrfs_release_path(path);
92 struct btrfs_free_space_info *
93 search_free_space_info(struct btrfs_trans_handle *trans,
94 struct btrfs_fs_info *fs_info,
95 struct btrfs_block_group_cache *block_group,
96 struct btrfs_path *path, int cow)
98 struct btrfs_root *root = fs_info->free_space_root;
102 key.objectid = block_group->key.objectid;
103 key.type = BTRFS_FREE_SPACE_INFO_KEY;
104 key.offset = block_group->key.offset;
106 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
110 btrfs_warn(fs_info, "missing free space info for %llu",
111 block_group->key.objectid);
113 return ERR_PTR(-ENOENT);
116 return btrfs_item_ptr(path->nodes[0], path->slots[0],
117 struct btrfs_free_space_info);
121 * btrfs_search_slot() but we're looking for the greatest key less than the
124 static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
125 struct btrfs_root *root,
126 struct btrfs_key *key, struct btrfs_path *p,
127 int ins_len, int cow)
131 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
140 if (p->slots[0] == 0) {
149 static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize)
151 return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
154 static u8 *alloc_bitmap(u32 bitmap_size)
159 * The allocation size varies, observed numbers were < 4K up to 16K.
160 * Using vmalloc unconditionally would be too heavy, we'll try
161 * contiguous allocations first.
163 if (bitmap_size <= PAGE_SIZE)
164 return kzalloc(bitmap_size, GFP_NOFS);
166 mem = kzalloc(bitmap_size, GFP_NOFS | __GFP_NOWARN);
170 return __vmalloc(bitmap_size, GFP_NOFS | __GFP_HIGHMEM | __GFP_ZERO,
174 int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
175 struct btrfs_fs_info *fs_info,
176 struct btrfs_block_group_cache *block_group,
177 struct btrfs_path *path)
179 struct btrfs_root *root = fs_info->free_space_root;
180 struct btrfs_free_space_info *info;
181 struct btrfs_key key, found_key;
182 struct extent_buffer *leaf;
183 u8 *bitmap, *bitmap_cursor;
186 u32 bitmap_size, flags, expected_extent_count;
187 u32 extent_count = 0;
191 bitmap_size = free_space_bitmap_size(block_group->key.offset,
192 fs_info->sectorsize);
193 bitmap = alloc_bitmap(bitmap_size);
199 start = block_group->key.objectid;
200 end = block_group->key.objectid + block_group->key.offset;
202 key.objectid = end - 1;
204 key.offset = (u64)-1;
207 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
211 leaf = path->nodes[0];
214 while (path->slots[0] > 0) {
215 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
217 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
218 ASSERT(found_key.objectid == block_group->key.objectid);
219 ASSERT(found_key.offset == block_group->key.offset);
222 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
225 ASSERT(found_key.objectid >= start);
226 ASSERT(found_key.objectid < end);
227 ASSERT(found_key.objectid + found_key.offset <= end);
229 first = div_u64(found_key.objectid - start,
230 fs_info->sectorsize);
231 last = div_u64(found_key.objectid + found_key.offset - start,
232 fs_info->sectorsize);
233 le_bitmap_set(bitmap, first, last - first);
243 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
246 btrfs_release_path(path);
249 info = search_free_space_info(trans, fs_info, block_group, path, 1);
254 leaf = path->nodes[0];
255 flags = btrfs_free_space_flags(leaf, info);
256 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
257 btrfs_set_free_space_flags(leaf, info, flags);
258 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
259 btrfs_mark_buffer_dirty(leaf);
260 btrfs_release_path(path);
262 if (extent_count != expected_extent_count) {
264 "incorrect extent count for %llu; counted %u, expected %u",
265 block_group->key.objectid, extent_count,
266 expected_extent_count);
272 bitmap_cursor = bitmap;
273 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
280 extent_size = min(end - i, bitmap_range);
281 data_size = free_space_bitmap_size(extent_size,
282 fs_info->sectorsize);
285 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
286 key.offset = extent_size;
288 ret = btrfs_insert_empty_item(trans, root, path, &key,
293 leaf = path->nodes[0];
294 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
295 write_extent_buffer(leaf, bitmap_cursor, ptr,
297 btrfs_mark_buffer_dirty(leaf);
298 btrfs_release_path(path);
301 bitmap_cursor += data_size;
308 btrfs_abort_transaction(trans, ret);
312 int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
313 struct btrfs_fs_info *fs_info,
314 struct btrfs_block_group_cache *block_group,
315 struct btrfs_path *path)
317 struct btrfs_root *root = fs_info->free_space_root;
318 struct btrfs_free_space_info *info;
319 struct btrfs_key key, found_key;
320 struct extent_buffer *leaf;
323 /* Initialize to silence GCC. */
324 u64 extent_start = 0;
326 u32 bitmap_size, flags, expected_extent_count;
327 int prev_bit = 0, bit, bitnr;
328 u32 extent_count = 0;
332 bitmap_size = free_space_bitmap_size(block_group->key.offset,
333 fs_info->sectorsize);
334 bitmap = alloc_bitmap(bitmap_size);
340 start = block_group->key.objectid;
341 end = block_group->key.objectid + block_group->key.offset;
343 key.objectid = end - 1;
345 key.offset = (u64)-1;
348 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
352 leaf = path->nodes[0];
355 while (path->slots[0] > 0) {
356 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
358 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
359 ASSERT(found_key.objectid == block_group->key.objectid);
360 ASSERT(found_key.offset == block_group->key.offset);
363 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
366 u32 bitmap_pos, data_size;
368 ASSERT(found_key.objectid >= start);
369 ASSERT(found_key.objectid < end);
370 ASSERT(found_key.objectid + found_key.offset <= end);
372 bitmap_pos = div_u64(found_key.objectid - start,
373 fs_info->sectorsize *
375 bitmap_cursor = bitmap + bitmap_pos;
376 data_size = free_space_bitmap_size(found_key.offset,
377 fs_info->sectorsize);
379 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
380 read_extent_buffer(leaf, bitmap_cursor, ptr,
390 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
393 btrfs_release_path(path);
396 info = search_free_space_info(trans, fs_info, block_group, path, 1);
401 leaf = path->nodes[0];
402 flags = btrfs_free_space_flags(leaf, info);
403 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
404 btrfs_set_free_space_flags(leaf, info, flags);
405 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
406 btrfs_mark_buffer_dirty(leaf);
407 btrfs_release_path(path);
411 while (offset < end) {
412 bit = !!le_test_bit(bitnr, bitmap);
413 if (prev_bit == 0 && bit == 1) {
414 extent_start = offset;
415 } else if (prev_bit == 1 && bit == 0) {
416 key.objectid = extent_start;
417 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
418 key.offset = offset - extent_start;
420 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
423 btrfs_release_path(path);
428 offset += fs_info->sectorsize;
432 key.objectid = extent_start;
433 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
434 key.offset = end - extent_start;
436 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
439 btrfs_release_path(path);
444 if (extent_count != expected_extent_count) {
446 "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, 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,
521 block_group->fs_info->sectorsize);
522 return !!extent_buffer_test_bit(leaf, ptr, i);
525 static void free_space_set_bits(struct btrfs_block_group_cache *block_group,
526 struct btrfs_path *path, u64 *start, u64 *size,
529 struct btrfs_fs_info *fs_info = block_group->fs_info;
530 struct extent_buffer *leaf;
531 struct btrfs_key key;
532 u64 end = *start + *size;
533 u64 found_start, found_end;
534 unsigned long ptr, first, last;
536 leaf = path->nodes[0];
537 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
538 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
540 found_start = key.objectid;
541 found_end = key.objectid + key.offset;
542 ASSERT(*start >= found_start && *start < found_end);
543 ASSERT(end > found_start);
548 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
549 first = div_u64(*start - found_start, fs_info->sectorsize);
550 last = div_u64(end - found_start, fs_info->sectorsize);
552 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
554 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
555 btrfs_mark_buffer_dirty(leaf);
557 *size -= end - *start;
562 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
563 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
564 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
567 static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
568 struct btrfs_root *root, struct btrfs_path *p)
570 struct btrfs_key key;
572 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
577 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
578 btrfs_release_path(p);
580 key.objectid += key.offset;
582 key.offset = (u64)-1;
584 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
588 * If remove is 1, then we are removing free space, thus clearing bits in the
589 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
592 static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
593 struct btrfs_fs_info *fs_info,
594 struct btrfs_block_group_cache *block_group,
595 struct btrfs_path *path,
596 u64 start, u64 size, int remove)
598 struct btrfs_root *root = fs_info->free_space_root;
599 struct btrfs_key key;
600 u64 end = start + size;
601 u64 cur_start, cur_size;
602 int prev_bit, next_bit;
607 * Read the bit for the block immediately before the extent of space if
608 * that block is within the block group.
610 if (start > block_group->key.objectid) {
611 u64 prev_block = start - block_group->fs_info->sectorsize;
613 key.objectid = prev_block;
615 key.offset = (u64)-1;
617 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
621 prev_bit = free_space_test_bit(block_group, path, prev_block);
623 /* The previous block may have been in the previous bitmap. */
624 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
625 if (start >= key.objectid + key.offset) {
626 ret = free_space_next_bitmap(trans, root, path);
631 key.objectid = start;
633 key.offset = (u64)-1;
635 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
643 * Iterate over all of the bitmaps overlapped by the extent of space,
644 * clearing/setting bits as required.
649 free_space_set_bits(block_group, path, &cur_start, &cur_size,
653 ret = free_space_next_bitmap(trans, root, path);
659 * Read the bit for the block immediately after the extent of space if
660 * that block is within the block group.
662 if (end < block_group->key.objectid + block_group->key.offset) {
663 /* The next block may be in the next bitmap. */
664 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
665 if (end >= key.objectid + key.offset) {
666 ret = free_space_next_bitmap(trans, root, path);
671 next_bit = free_space_test_bit(block_group, path, end);
679 /* Leftover on the left. */
683 /* Leftover on the right. */
689 /* Merging with neighbor on the left. */
693 /* Merging with neighbor on the right. */
698 btrfs_release_path(path);
699 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
706 static int remove_free_space_extent(struct btrfs_trans_handle *trans,
707 struct btrfs_fs_info *fs_info,
708 struct btrfs_block_group_cache *block_group,
709 struct btrfs_path *path,
712 struct btrfs_root *root = fs_info->free_space_root;
713 struct btrfs_key key;
714 u64 found_start, found_end;
715 u64 end = start + size;
716 int new_extents = -1;
719 key.objectid = start;
721 key.offset = (u64)-1;
723 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
727 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
729 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
731 found_start = key.objectid;
732 found_end = key.objectid + key.offset;
733 ASSERT(start >= found_start && end <= found_end);
736 * Okay, now that we've found the free space extent which contains the
737 * free space that we are removing, there are four cases:
739 * 1. We're using the whole extent: delete the key we found and
740 * decrement the free space extent count.
741 * 2. We are using part of the extent starting at the beginning: delete
742 * the key we found and insert a new key representing the leftover at
743 * the end. There is no net change in the number of extents.
744 * 3. We are using part of the extent ending at the end: delete the key
745 * we found and insert a new key representing the leftover at the
746 * beginning. There is no net change in the number of extents.
747 * 4. We are using part of the extent in the middle: delete the key we
748 * found and insert two new keys representing the leftovers on each
749 * side. Where we used to have one extent, we now have two, so increment
750 * the extent count. We may need to convert the block group to bitmaps
754 /* Delete the existing key (cases 1-4). */
755 ret = btrfs_del_item(trans, root, path);
759 /* Add a key for leftovers at the beginning (cases 3 and 4). */
760 if (start > found_start) {
761 key.objectid = found_start;
762 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
763 key.offset = start - found_start;
765 btrfs_release_path(path);
766 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
772 /* Add a key for leftovers at the end (cases 2 and 4). */
773 if (end < found_end) {
775 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
776 key.offset = found_end - end;
778 btrfs_release_path(path);
779 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
785 btrfs_release_path(path);
786 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
793 int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
794 struct btrfs_fs_info *fs_info,
795 struct btrfs_block_group_cache *block_group,
796 struct btrfs_path *path, u64 start, u64 size)
798 struct btrfs_free_space_info *info;
802 if (block_group->needs_free_space) {
803 ret = __add_block_group_free_space(trans, fs_info, block_group,
809 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
811 return PTR_ERR(info);
812 flags = btrfs_free_space_flags(path->nodes[0], info);
813 btrfs_release_path(path);
815 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
816 return modify_free_space_bitmap(trans, fs_info, block_group,
817 path, start, size, 1);
819 return remove_free_space_extent(trans, fs_info, block_group,
824 int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
825 struct btrfs_fs_info *fs_info,
828 struct btrfs_block_group_cache *block_group;
829 struct btrfs_path *path;
832 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
835 path = btrfs_alloc_path();
841 block_group = btrfs_lookup_block_group(fs_info, start);
848 mutex_lock(&block_group->free_space_lock);
849 ret = __remove_from_free_space_tree(trans, fs_info, block_group, path,
851 mutex_unlock(&block_group->free_space_lock);
853 btrfs_put_block_group(block_group);
855 btrfs_free_path(path);
857 btrfs_abort_transaction(trans, ret);
861 static int add_free_space_extent(struct btrfs_trans_handle *trans,
862 struct btrfs_fs_info *fs_info,
863 struct btrfs_block_group_cache *block_group,
864 struct btrfs_path *path,
867 struct btrfs_root *root = fs_info->free_space_root;
868 struct btrfs_key key, new_key;
869 u64 found_start, found_end;
870 u64 end = start + size;
875 * We are adding a new extent of free space, but we need to merge
876 * extents. There are four cases here:
878 * 1. The new extent does not have any immediate neighbors to merge
879 * with: add the new key and increment the free space extent count. We
880 * may need to convert the block group to bitmaps as a result.
881 * 2. The new extent has an immediate neighbor before it: remove the
882 * previous key and insert a new key combining both of them. There is no
883 * net change in the number of extents.
884 * 3. The new extent has an immediate neighbor after it: remove the next
885 * key and insert a new key combining both of them. There is no net
886 * change in the number of extents.
887 * 4. The new extent has immediate neighbors on both sides: remove both
888 * of the keys and insert a new key combining all of them. Where we used
889 * to have two extents, we now have one, so decrement the extent count.
892 new_key.objectid = start;
893 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
894 new_key.offset = size;
896 /* Search for a neighbor on the left. */
897 if (start == block_group->key.objectid)
899 key.objectid = start - 1;
901 key.offset = (u64)-1;
903 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
907 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
909 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
910 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
911 btrfs_release_path(path);
915 found_start = key.objectid;
916 found_end = key.objectid + key.offset;
917 ASSERT(found_start >= block_group->key.objectid &&
918 found_end > block_group->key.objectid);
919 ASSERT(found_start < start && found_end <= start);
922 * Delete the neighbor on the left and absorb it into the new key (cases
925 if (found_end == start) {
926 ret = btrfs_del_item(trans, root, path);
929 new_key.objectid = found_start;
930 new_key.offset += key.offset;
933 btrfs_release_path(path);
936 /* Search for a neighbor on the right. */
937 if (end == block_group->key.objectid + block_group->key.offset)
941 key.offset = (u64)-1;
943 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
947 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
949 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
950 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
951 btrfs_release_path(path);
955 found_start = key.objectid;
956 found_end = key.objectid + key.offset;
957 ASSERT(found_start >= block_group->key.objectid &&
958 found_end > block_group->key.objectid);
959 ASSERT((found_start < start && found_end <= start) ||
960 (found_start >= end && found_end > end));
963 * Delete the neighbor on the right and absorb it into the new key
966 if (found_start == end) {
967 ret = btrfs_del_item(trans, root, path);
970 new_key.offset += key.offset;
973 btrfs_release_path(path);
976 /* Insert the new key (cases 1-4). */
977 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
981 btrfs_release_path(path);
982 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
989 int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
990 struct btrfs_fs_info *fs_info,
991 struct btrfs_block_group_cache *block_group,
992 struct btrfs_path *path, u64 start, u64 size)
994 struct btrfs_free_space_info *info;
998 if (block_group->needs_free_space) {
999 ret = __add_block_group_free_space(trans, fs_info, block_group,
1005 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
1007 return PTR_ERR(info);
1008 flags = btrfs_free_space_flags(path->nodes[0], info);
1009 btrfs_release_path(path);
1011 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
1012 return modify_free_space_bitmap(trans, fs_info, block_group,
1013 path, start, size, 0);
1015 return add_free_space_extent(trans, fs_info, block_group, path,
1020 int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1021 struct btrfs_fs_info *fs_info,
1022 u64 start, u64 size)
1024 struct btrfs_block_group_cache *block_group;
1025 struct btrfs_path *path;
1028 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1031 path = btrfs_alloc_path();
1037 block_group = btrfs_lookup_block_group(fs_info, start);
1044 mutex_lock(&block_group->free_space_lock);
1045 ret = __add_to_free_space_tree(trans, fs_info, block_group, path, start,
1047 mutex_unlock(&block_group->free_space_lock);
1049 btrfs_put_block_group(block_group);
1051 btrfs_free_path(path);
1053 btrfs_abort_transaction(trans, ret);
1058 * Populate the free space tree by walking the extent tree. Operations on the
1059 * extent tree that happen as a result of writes to the free space tree will go
1060 * through the normal add/remove hooks.
1062 static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1063 struct btrfs_fs_info *fs_info,
1064 struct btrfs_block_group_cache *block_group)
1066 struct btrfs_root *extent_root = fs_info->extent_root;
1067 struct btrfs_path *path, *path2;
1068 struct btrfs_key key;
1072 path = btrfs_alloc_path();
1077 path2 = btrfs_alloc_path();
1079 btrfs_free_path(path);
1083 ret = add_new_free_space_info(trans, fs_info, block_group, path2);
1087 mutex_lock(&block_group->free_space_lock);
1090 * Iterate through all of the extent and metadata items in this block
1091 * group, adding the free space between them and the free space at the
1092 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1093 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1096 key.objectid = block_group->key.objectid;
1097 key.type = BTRFS_EXTENT_ITEM_KEY;
1100 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1105 start = block_group->key.objectid;
1106 end = block_group->key.objectid + block_group->key.offset;
1108 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1110 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1111 key.type == BTRFS_METADATA_ITEM_KEY) {
1112 if (key.objectid >= end)
1115 if (start < key.objectid) {
1116 ret = __add_to_free_space_tree(trans, fs_info,
1124 start = key.objectid;
1125 if (key.type == BTRFS_METADATA_ITEM_KEY)
1126 start += fs_info->nodesize;
1128 start += key.offset;
1129 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1130 if (key.objectid != block_group->key.objectid)
1134 ret = btrfs_next_item(extent_root, path);
1141 ret = __add_to_free_space_tree(trans, fs_info, block_group,
1142 path2, start, end - start);
1149 mutex_unlock(&block_group->free_space_lock);
1151 btrfs_free_path(path2);
1152 btrfs_free_path(path);
1156 int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1158 struct btrfs_trans_handle *trans;
1159 struct btrfs_root *tree_root = fs_info->tree_root;
1160 struct btrfs_root *free_space_root;
1161 struct btrfs_block_group_cache *block_group;
1162 struct rb_node *node;
1165 trans = btrfs_start_transaction(tree_root, 0);
1167 return PTR_ERR(trans);
1169 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1170 free_space_root = btrfs_create_tree(trans, fs_info,
1171 BTRFS_FREE_SPACE_TREE_OBJECTID);
1172 if (IS_ERR(free_space_root)) {
1173 ret = PTR_ERR(free_space_root);
1176 fs_info->free_space_root = free_space_root;
1178 node = rb_first(&fs_info->block_group_cache_tree);
1180 block_group = rb_entry(node, struct btrfs_block_group_cache,
1182 ret = populate_free_space_tree(trans, fs_info, block_group);
1185 node = rb_next(node);
1188 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1189 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1190 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1192 ret = btrfs_commit_transaction(trans);
1199 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1200 btrfs_abort_transaction(trans, ret);
1201 btrfs_end_transaction(trans);
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_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1259 fs_info->free_space_root = NULL;
1261 ret = clear_free_space_tree(trans, free_space_root);
1265 ret = btrfs_del_root(trans, tree_root, &free_space_root->root_key);
1269 list_del(&free_space_root->dirty_list);
1271 btrfs_tree_lock(free_space_root->node);
1272 clean_tree_block(fs_info, free_space_root->node);
1273 btrfs_tree_unlock(free_space_root->node);
1274 btrfs_free_tree_block(trans, free_space_root, free_space_root->node,
1277 free_extent_buffer(free_space_root->node);
1278 free_extent_buffer(free_space_root->commit_root);
1279 kfree(free_space_root);
1281 ret = btrfs_commit_transaction(trans);
1288 btrfs_abort_transaction(trans, ret);
1289 btrfs_end_transaction(trans);
1293 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
1294 struct btrfs_fs_info *fs_info,
1295 struct btrfs_block_group_cache *block_group,
1296 struct btrfs_path *path)
1301 start = block_group->key.objectid;
1302 end = block_group->key.objectid + block_group->key.offset;
1304 block_group->needs_free_space = 0;
1306 ret = add_new_free_space_info(trans, fs_info, block_group, path);
1310 return __add_to_free_space_tree(trans, fs_info, block_group, path,
1311 block_group->key.objectid,
1312 block_group->key.offset);
1315 int add_block_group_free_space(struct btrfs_trans_handle *trans,
1316 struct btrfs_fs_info *fs_info,
1317 struct btrfs_block_group_cache *block_group)
1319 struct btrfs_path *path = NULL;
1322 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1325 mutex_lock(&block_group->free_space_lock);
1326 if (!block_group->needs_free_space)
1329 path = btrfs_alloc_path();
1335 ret = __add_block_group_free_space(trans, fs_info, block_group, path);
1338 btrfs_free_path(path);
1339 mutex_unlock(&block_group->free_space_lock);
1341 btrfs_abort_transaction(trans, ret);
1345 int remove_block_group_free_space(struct btrfs_trans_handle *trans,
1346 struct btrfs_fs_info *fs_info,
1347 struct btrfs_block_group_cache *block_group)
1349 struct btrfs_root *root = fs_info->free_space_root;
1350 struct btrfs_path *path;
1351 struct btrfs_key key, found_key;
1352 struct extent_buffer *leaf;
1357 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1360 if (block_group->needs_free_space) {
1361 /* We never added this block group to the free space tree. */
1365 path = btrfs_alloc_path();
1371 start = block_group->key.objectid;
1372 end = block_group->key.objectid + block_group->key.offset;
1374 key.objectid = end - 1;
1376 key.offset = (u64)-1;
1379 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1383 leaf = path->nodes[0];
1386 while (path->slots[0] > 0) {
1387 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1389 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
1390 ASSERT(found_key.objectid == block_group->key.objectid);
1391 ASSERT(found_key.offset == block_group->key.offset);
1396 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY ||
1397 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
1398 ASSERT(found_key.objectid >= start);
1399 ASSERT(found_key.objectid < end);
1400 ASSERT(found_key.objectid + found_key.offset <= end);
1408 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1411 btrfs_release_path(path);
1416 btrfs_free_path(path);
1418 btrfs_abort_transaction(trans, ret);
1422 static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1423 struct btrfs_path *path,
1424 u32 expected_extent_count)
1426 struct btrfs_block_group_cache *block_group;
1427 struct btrfs_fs_info *fs_info;
1428 struct btrfs_root *root;
1429 struct btrfs_key key;
1430 int prev_bit = 0, bit;
1431 /* Initialize to silence GCC. */
1432 u64 extent_start = 0;
1434 u64 total_found = 0;
1435 u32 extent_count = 0;
1438 block_group = caching_ctl->block_group;
1439 fs_info = block_group->fs_info;
1440 root = fs_info->free_space_root;
1442 end = block_group->key.objectid + block_group->key.offset;
1445 ret = btrfs_next_item(root, path);
1451 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1453 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1456 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1457 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1459 caching_ctl->progress = key.objectid;
1461 offset = key.objectid;
1462 while (offset < key.objectid + key.offset) {
1463 bit = free_space_test_bit(block_group, path, offset);
1464 if (prev_bit == 0 && bit == 1) {
1465 extent_start = offset;
1466 } else if (prev_bit == 1 && bit == 0) {
1467 total_found += add_new_free_space(block_group,
1471 if (total_found > CACHING_CTL_WAKE_UP) {
1473 wake_up(&caching_ctl->wait);
1478 offset += fs_info->sectorsize;
1481 if (prev_bit == 1) {
1482 total_found += add_new_free_space(block_group, fs_info,
1487 if (extent_count != expected_extent_count) {
1489 "incorrect extent count for %llu; counted %u, expected %u",
1490 block_group->key.objectid, extent_count,
1491 expected_extent_count);
1497 caching_ctl->progress = (u64)-1;
1504 static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1505 struct btrfs_path *path,
1506 u32 expected_extent_count)
1508 struct btrfs_block_group_cache *block_group;
1509 struct btrfs_fs_info *fs_info;
1510 struct btrfs_root *root;
1511 struct btrfs_key key;
1513 u64 total_found = 0;
1514 u32 extent_count = 0;
1517 block_group = caching_ctl->block_group;
1518 fs_info = block_group->fs_info;
1519 root = fs_info->free_space_root;
1521 end = block_group->key.objectid + block_group->key.offset;
1524 ret = btrfs_next_item(root, path);
1530 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1532 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1535 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1536 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1538 caching_ctl->progress = key.objectid;
1540 total_found += add_new_free_space(block_group, fs_info,
1542 key.objectid + key.offset);
1543 if (total_found > CACHING_CTL_WAKE_UP) {
1545 wake_up(&caching_ctl->wait);
1550 if (extent_count != expected_extent_count) {
1552 "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);