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1/*
2 * Copyright (C) 2015 Facebook. All rights reserved.
3 *
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.
7 *
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.
12 *
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.
17 */
18
19#include <linux/kernel.h>
20#include <linux/vmalloc.h>
21#include "ctree.h"
22#include "disk-io.h"
23#include "locking.h"
24#include "free-space-tree.h"
25#include "transaction.h"
26
27static 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);
31
32void set_free_space_tree_thresholds(struct btrfs_block_group_cache *cache)
33{
34 u32 bitmap_range;
35 size_t bitmap_size;
36 u64 num_bitmaps, total_bitmap_size;
37
38 /*
39 * We convert to bitmaps when the disk space required for using extents
40 * exceeds that required for using bitmaps.
41 */
42 bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
43 num_bitmaps = div_u64(cache->key.offset + bitmap_range - 1,
44 bitmap_range);
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));
49
50 /*
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.
53 */
54 if (cache->bitmap_high_thresh > 100)
55 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
56 else
57 cache->bitmap_low_thresh = 0;
58}
59
60static 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)
64{
65 struct btrfs_root *root = fs_info->free_space_root;
66 struct btrfs_free_space_info *info;
67 struct btrfs_key key;
68 struct extent_buffer *leaf;
69 int ret;
70
71 key.objectid = block_group->key.objectid;
72 key.type = BTRFS_FREE_SPACE_INFO_KEY;
73 key.offset = block_group->key.offset;
74
75 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
76 if (ret)
77 goto out;
78
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);
85
86 ret = 0;
87out:
88 btrfs_release_path(path);
89 return ret;
90}
91
92struct btrfs_free_space_info *
93search_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)
97{
98 struct btrfs_root *root = fs_info->free_space_root;
99 struct btrfs_key key;
100 int ret;
101
102 key.objectid = block_group->key.objectid;
103 key.type = BTRFS_FREE_SPACE_INFO_KEY;
104 key.offset = block_group->key.offset;
105
106 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
107 if (ret < 0)
108 return ERR_PTR(ret);
109 if (ret != 0) {
110 btrfs_warn(fs_info, "missing free space info for %llu",
111 block_group->key.objectid);
112 ASSERT(0);
113 return ERR_PTR(-ENOENT);
114 }
115
116 return btrfs_item_ptr(path->nodes[0], path->slots[0],
117 struct btrfs_free_space_info);
118}
119
120/*
121 * btrfs_search_slot() but we're looking for the greatest key less than the
122 * passed key.
123 */
124static 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)
128{
129 int ret;
130
131 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
132 if (ret < 0)
133 return ret;
134
135 if (ret == 0) {
136 ASSERT(0);
137 return -EIO;
138 }
139
140 if (p->slots[0] == 0) {
141 ASSERT(0);
142 return -EIO;
143 }
144 p->slots[0]--;
145
146 return 0;
147}
148
149static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize)
150{
151 return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
152}
153
154static u8 *alloc_bitmap(u32 bitmap_size)
155{
156 void *mem;
157
158 /*
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.
162 */
163 if (bitmap_size <= PAGE_SIZE)
164 return kzalloc(bitmap_size, GFP_NOFS);
165
166 mem = kzalloc(bitmap_size, GFP_NOFS | __GFP_NOWARN);
167 if (mem)
168 return mem;
169
170 return __vmalloc(bitmap_size, GFP_NOFS | __GFP_HIGHMEM | __GFP_ZERO,
171 PAGE_KERNEL);
172}
173
174int 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)
178{
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;
184 u64 start, end;
185 u64 bitmap_range, i;
186 u32 bitmap_size, flags, expected_extent_count;
187 u32 extent_count = 0;
188 int done = 0, nr;
189 int ret;
190
191 bitmap_size = free_space_bitmap_size(block_group->key.offset,
192 fs_info->sectorsize);
193 bitmap = alloc_bitmap(bitmap_size);
194 if (!bitmap) {
195 ret = -ENOMEM;
196 goto out;
197 }
198
199 start = block_group->key.objectid;
200 end = block_group->key.objectid + block_group->key.offset;
201
202 key.objectid = end - 1;
203 key.type = (u8)-1;
204 key.offset = (u64)-1;
205
206 while (!done) {
207 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
208 if (ret)
209 goto out;
210
211 leaf = path->nodes[0];
212 nr = 0;
213 path->slots[0]++;
214 while (path->slots[0] > 0) {
215 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
216
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);
220 done = 1;
221 break;
222 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
223 u64 first, last;
224
225 ASSERT(found_key.objectid >= start);
226 ASSERT(found_key.objectid < end);
227 ASSERT(found_key.objectid + found_key.offset <= end);
228
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);
234
235 extent_count++;
236 nr++;
237 path->slots[0]--;
238 } else {
239 ASSERT(0);
240 }
241 }
242
243 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
244 if (ret)
245 goto out;
246 btrfs_release_path(path);
247 }
248
249 info = search_free_space_info(trans, fs_info, block_group, path, 1);
250 if (IS_ERR(info)) {
251 ret = PTR_ERR(info);
252 goto out;
253 }
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);
261
262 if (extent_count != expected_extent_count) {
263 btrfs_err(fs_info,
264 "incorrect extent count for %llu; counted %u, expected %u",
265 block_group->key.objectid, extent_count,
266 expected_extent_count);
267 ASSERT(0);
268 ret = -EIO;
269 goto out;
270 }
271
272 bitmap_cursor = bitmap;
273 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
274 i = start;
275 while (i < end) {
276 unsigned long ptr;
277 u64 extent_size;
278 u32 data_size;
279
280 extent_size = min(end - i, bitmap_range);
281 data_size = free_space_bitmap_size(extent_size,
282 fs_info->sectorsize);
283
284 key.objectid = i;
285 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
286 key.offset = extent_size;
287
288 ret = btrfs_insert_empty_item(trans, root, path, &key,
289 data_size);
290 if (ret)
291 goto out;
292
293 leaf = path->nodes[0];
294 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
295 write_extent_buffer(leaf, bitmap_cursor, ptr,
296 data_size);
297 btrfs_mark_buffer_dirty(leaf);
298 btrfs_release_path(path);
299
300 i += extent_size;
301 bitmap_cursor += data_size;
302 }
303
304 ret = 0;
305out:
306 kvfree(bitmap);
307 if (ret)
308 btrfs_abort_transaction(trans, ret);
309 return ret;
310}
311
312int 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)
316{
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;
321 u8 *bitmap;
322 u64 start, end;
323 /* Initialize to silence GCC. */
324 u64 extent_start = 0;
325 u64 offset;
326 u32 bitmap_size, flags, expected_extent_count;
327 int prev_bit = 0, bit, bitnr;
328 u32 extent_count = 0;
329 int done = 0, nr;
330 int ret;
331
332 bitmap_size = free_space_bitmap_size(block_group->key.offset,
333 fs_info->sectorsize);
334 bitmap = alloc_bitmap(bitmap_size);
335 if (!bitmap) {
336 ret = -ENOMEM;
337 goto out;
338 }
339
340 start = block_group->key.objectid;
341 end = block_group->key.objectid + block_group->key.offset;
342
343 key.objectid = end - 1;
344 key.type = (u8)-1;
345 key.offset = (u64)-1;
346
347 while (!done) {
348 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
349 if (ret)
350 goto out;
351
352 leaf = path->nodes[0];
353 nr = 0;
354 path->slots[0]++;
355 while (path->slots[0] > 0) {
356 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
357
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);
361 done = 1;
362 break;
363 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
364 unsigned long ptr;
365 u8 *bitmap_cursor;
366 u32 bitmap_pos, data_size;
367
368 ASSERT(found_key.objectid >= start);
369 ASSERT(found_key.objectid < end);
370 ASSERT(found_key.objectid + found_key.offset <= end);
371
372 bitmap_pos = div_u64(found_key.objectid - start,
373 fs_info->sectorsize *
374 BITS_PER_BYTE);
375 bitmap_cursor = bitmap + bitmap_pos;
376 data_size = free_space_bitmap_size(found_key.offset,
377 fs_info->sectorsize);
378
379 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
380 read_extent_buffer(leaf, bitmap_cursor, ptr,
381 data_size);
382
383 nr++;
384 path->slots[0]--;
385 } else {
386 ASSERT(0);
387 }
388 }
389
390 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
391 if (ret)
392 goto out;
393 btrfs_release_path(path);
394 }
395
396 info = search_free_space_info(trans, fs_info, block_group, path, 1);
397 if (IS_ERR(info)) {
398 ret = PTR_ERR(info);
399 goto out;
400 }
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);
408
409 offset = start;
410 bitnr = 0;
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;
419
420 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
421 if (ret)
422 goto out;
423 btrfs_release_path(path);
424
425 extent_count++;
426 }
427 prev_bit = bit;
428 offset += fs_info->sectorsize;
429 bitnr++;
430 }
431 if (prev_bit == 1) {
432 key.objectid = extent_start;
433 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
434 key.offset = end - extent_start;
435
436 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
437 if (ret)
438 goto out;
439 btrfs_release_path(path);
440
441 extent_count++;
442 }
443
444 if (extent_count != expected_extent_count) {
445 btrfs_err(fs_info,
446 "incorrect extent count for %llu; counted %u, expected %u",
447 block_group->key.objectid, extent_count,
448 expected_extent_count);
449 ASSERT(0);
450 ret = -EIO;
451 goto out;
452 }
453
454 ret = 0;
455out:
456 kvfree(bitmap);
457 if (ret)
458 btrfs_abort_transaction(trans, ret);
459 return ret;
460}
461
462static 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,
466 int new_extents)
467{
468 struct btrfs_free_space_info *info;
469 u32 flags;
470 u32 extent_count;
471 int ret = 0;
472
473 if (new_extents == 0)
474 return 0;
475
476 info = search_free_space_info(trans, fs_info, block_group, path, 1);
477 if (IS_ERR(info)) {
478 ret = PTR_ERR(info);
479 goto out;
480 }
481 flags = btrfs_free_space_flags(path->nodes[0], info);
482 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
483
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);
488
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,
492 path);
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,
496 path);
497 }
498
499out:
500 return ret;
501}
502
503int free_space_test_bit(struct btrfs_block_group_cache *block_group,
504 struct btrfs_path *path, u64 offset)
505{
506 struct extent_buffer *leaf;
507 struct btrfs_key key;
508 u64 found_start, found_end;
509 unsigned long ptr, i;
510
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);
514
515 found_start = key.objectid;
516 found_end = key.objectid + key.offset;
517 ASSERT(offset >= found_start && offset < found_end);
518
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);
523}
524
525static void free_space_set_bits(struct btrfs_block_group_cache *block_group,
526 struct btrfs_path *path, u64 *start, u64 *size,
527 int bit)
528{
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;
535
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);
539
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);
544
545 if (end > found_end)
546 end = found_end;
547
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);
551 if (bit)
552 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
553 else
554 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
555 btrfs_mark_buffer_dirty(leaf);
556
557 *size -= end - *start;
558 *start = end;
559}
560
561/*
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
565 * looking for.
566 */
567static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
568 struct btrfs_root *root, struct btrfs_path *p)
569{
570 struct btrfs_key key;
571
572 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
573 p->slots[0]++;
574 return 0;
575 }
576
577 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
578 btrfs_release_path(p);
579
580 key.objectid += key.offset;
581 key.type = (u8)-1;
582 key.offset = (u64)-1;
583
584 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
585}
586
587/*
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
590 * the bitmap.
591 */
592static 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)
597{
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;
603 int new_extents;
604 int ret;
605
606 /*
607 * Read the bit for the block immediately before the extent of space if
608 * that block is within the block group.
609 */
610 if (start > block_group->key.objectid) {
611 u64 prev_block = start - block_group->fs_info->sectorsize;
612
613 key.objectid = prev_block;
614 key.type = (u8)-1;
615 key.offset = (u64)-1;
616
617 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
618 if (ret)
619 goto out;
620
621 prev_bit = free_space_test_bit(block_group, path, prev_block);
622
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);
627 if (ret)
628 goto out;
629 }
630 } else {
631 key.objectid = start;
632 key.type = (u8)-1;
633 key.offset = (u64)-1;
634
635 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
636 if (ret)
637 goto out;
638
639 prev_bit = -1;
640 }
641
642 /*
643 * Iterate over all of the bitmaps overlapped by the extent of space,
644 * clearing/setting bits as required.
645 */
646 cur_start = start;
647 cur_size = size;
648 while (1) {
649 free_space_set_bits(block_group, path, &cur_start, &cur_size,
650 !remove);
651 if (cur_size == 0)
652 break;
653 ret = free_space_next_bitmap(trans, root, path);
654 if (ret)
655 goto out;
656 }
657
658 /*
659 * Read the bit for the block immediately after the extent of space if
660 * that block is within the block group.
661 */
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);
667 if (ret)
668 goto out;
669 }
670
671 next_bit = free_space_test_bit(block_group, path, end);
672 } else {
673 next_bit = -1;
674 }
675
676 if (remove) {
677 new_extents = -1;
678 if (prev_bit == 1) {
679 /* Leftover on the left. */
680 new_extents++;
681 }
682 if (next_bit == 1) {
683 /* Leftover on the right. */
684 new_extents++;
685 }
686 } else {
687 new_extents = 1;
688 if (prev_bit == 1) {
689 /* Merging with neighbor on the left. */
690 new_extents--;
691 }
692 if (next_bit == 1) {
693 /* Merging with neighbor on the right. */
694 new_extents--;
695 }
696 }
697
698 btrfs_release_path(path);
699 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
700 new_extents);
701
702out:
703 return ret;
704}
705
706static 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,
710 u64 start, u64 size)
711{
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;
717 int ret;
718
719 key.objectid = start;
720 key.type = (u8)-1;
721 key.offset = (u64)-1;
722
723 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
724 if (ret)
725 goto out;
726
727 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
728
729 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
730
731 found_start = key.objectid;
732 found_end = key.objectid + key.offset;
733 ASSERT(start >= found_start && end <= found_end);
734
735 /*
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:
738 *
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
751 * as a result.
752 */
753
754 /* Delete the existing key (cases 1-4). */
755 ret = btrfs_del_item(trans, root, path);
756 if (ret)
757 goto out;
758
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;
764
765 btrfs_release_path(path);
766 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
767 if (ret)
768 goto out;
769 new_extents++;
770 }
771
772 /* Add a key for leftovers at the end (cases 2 and 4). */
773 if (end < found_end) {
774 key.objectid = end;
775 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
776 key.offset = found_end - end;
777
778 btrfs_release_path(path);
779 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
780 if (ret)
781 goto out;
782 new_extents++;
783 }
784
785 btrfs_release_path(path);
786 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
787 new_extents);
788
789out:
790 return ret;
791}
792
793int __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)
797{
798 struct btrfs_free_space_info *info;
799 u32 flags;
800 int ret;
801
802 if (block_group->needs_free_space) {
803 ret = __add_block_group_free_space(trans, fs_info, block_group,
804 path);
805 if (ret)
806 return ret;
807 }
808
809 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
810 if (IS_ERR(info))
811 return PTR_ERR(info);
812 flags = btrfs_free_space_flags(path->nodes[0], info);
813 btrfs_release_path(path);
814
815 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
816 return modify_free_space_bitmap(trans, fs_info, block_group,
817 path, start, size, 1);
818 } else {
819 return remove_free_space_extent(trans, fs_info, block_group,
820 path, start, size);
821 }
822}
823
824int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
825 struct btrfs_fs_info *fs_info,
826 u64 start, u64 size)
827{
828 struct btrfs_block_group_cache *block_group;
829 struct btrfs_path *path;
830 int ret;
831
832 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
833 return 0;
834
835 path = btrfs_alloc_path();
836 if (!path) {
837 ret = -ENOMEM;
838 goto out;
839 }
840
841 block_group = btrfs_lookup_block_group(fs_info, start);
842 if (!block_group) {
843 ASSERT(0);
844 ret = -ENOENT;
845 goto out;
846 }
847
848 mutex_lock(&block_group->free_space_lock);
849 ret = __remove_from_free_space_tree(trans, fs_info, block_group, path,
850 start, size);
851 mutex_unlock(&block_group->free_space_lock);
852
853 btrfs_put_block_group(block_group);
854out:
855 btrfs_free_path(path);
856 if (ret)
857 btrfs_abort_transaction(trans, ret);
858 return ret;
859}
860
861static 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,
865 u64 start, u64 size)
866{
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;
871 int new_extents = 1;
872 int ret;
873
874 /*
875 * We are adding a new extent of free space, but we need to merge
876 * extents. There are four cases here:
877 *
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.
890 */
891
892 new_key.objectid = start;
893 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
894 new_key.offset = size;
895
896 /* Search for a neighbor on the left. */
897 if (start == block_group->key.objectid)
898 goto right;
899 key.objectid = start - 1;
900 key.type = (u8)-1;
901 key.offset = (u64)-1;
902
903 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
904 if (ret)
905 goto out;
906
907 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
908
909 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
910 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
911 btrfs_release_path(path);
912 goto right;
913 }
914
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);
920
921 /*
922 * Delete the neighbor on the left and absorb it into the new key (cases
923 * 2 and 4).
924 */
925 if (found_end == start) {
926 ret = btrfs_del_item(trans, root, path);
927 if (ret)
928 goto out;
929 new_key.objectid = found_start;
930 new_key.offset += key.offset;
931 new_extents--;
932 }
933 btrfs_release_path(path);
934
935right:
936 /* Search for a neighbor on the right. */
937 if (end == block_group->key.objectid + block_group->key.offset)
938 goto insert;
939 key.objectid = end;
940 key.type = (u8)-1;
941 key.offset = (u64)-1;
942
943 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
944 if (ret)
945 goto out;
946
947 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
948
949 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
950 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
951 btrfs_release_path(path);
952 goto insert;
953 }
954
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));
961
962 /*
963 * Delete the neighbor on the right and absorb it into the new key
964 * (cases 3 and 4).
965 */
966 if (found_start == end) {
967 ret = btrfs_del_item(trans, root, path);
968 if (ret)
969 goto out;
970 new_key.offset += key.offset;
971 new_extents--;
972 }
973 btrfs_release_path(path);
974
975insert:
976 /* Insert the new key (cases 1-4). */
977 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
978 if (ret)
979 goto out;
980
981 btrfs_release_path(path);
982 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
983 new_extents);
984
985out:
986 return ret;
987}
988
989int __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)
993{
994 struct btrfs_free_space_info *info;
995 u32 flags;
996 int ret;
997
998 if (block_group->needs_free_space) {
999 ret = __add_block_group_free_space(trans, fs_info, block_group,
1000 path);
1001 if (ret)
1002 return ret;
1003 }
1004
1005 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
1006 if (IS_ERR(info))
1007 return PTR_ERR(info);
1008 flags = btrfs_free_space_flags(path->nodes[0], info);
1009 btrfs_release_path(path);
1010
1011 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
1012 return modify_free_space_bitmap(trans, fs_info, block_group,
1013 path, start, size, 0);
1014 } else {
1015 return add_free_space_extent(trans, fs_info, block_group, path,
1016 start, size);
1017 }
1018}
1019
1020int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1021 struct btrfs_fs_info *fs_info,
1022 u64 start, u64 size)
1023{
1024 struct btrfs_block_group_cache *block_group;
1025 struct btrfs_path *path;
1026 int ret;
1027
1028 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1029 return 0;
1030
1031 path = btrfs_alloc_path();
1032 if (!path) {
1033 ret = -ENOMEM;
1034 goto out;
1035 }
1036
1037 block_group = btrfs_lookup_block_group(fs_info, start);
1038 if (!block_group) {
1039 ASSERT(0);
1040 ret = -ENOENT;
1041 goto out;
1042 }
1043
1044 mutex_lock(&block_group->free_space_lock);
1045 ret = __add_to_free_space_tree(trans, fs_info, block_group, path, start,
1046 size);
1047 mutex_unlock(&block_group->free_space_lock);
1048
1049 btrfs_put_block_group(block_group);
1050out:
1051 btrfs_free_path(path);
1052 if (ret)
1053 btrfs_abort_transaction(trans, ret);
1054 return ret;
1055}
1056
1057/*
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.
1061 */
1062static 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)
1065{
1066 struct btrfs_root *extent_root = fs_info->extent_root;
1067 struct btrfs_path *path, *path2;
1068 struct btrfs_key key;
1069 u64 start, end;
1070 int ret;
1071
1072 path = btrfs_alloc_path();
1073 if (!path)
1074 return -ENOMEM;
1075 path->reada = 1;
1076
1077 path2 = btrfs_alloc_path();
1078 if (!path2) {
1079 btrfs_free_path(path);
1080 return -ENOMEM;
1081 }
1082
1083 ret = add_new_free_space_info(trans, fs_info, block_group, path2);
1084 if (ret)
1085 goto out;
1086
1087 mutex_lock(&block_group->free_space_lock);
1088
1089 /*
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
1094 * contained in.
1095 */
1096 key.objectid = block_group->key.objectid;
1097 key.type = BTRFS_EXTENT_ITEM_KEY;
1098 key.offset = 0;
1099
1100 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1101 if (ret < 0)
1102 goto out_locked;
1103 ASSERT(ret == 0);
1104
1105 start = block_group->key.objectid;
1106 end = block_group->key.objectid + block_group->key.offset;
1107 while (1) {
1108 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1109
1110 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1111 key.type == BTRFS_METADATA_ITEM_KEY) {
1112 if (key.objectid >= end)
1113 break;
1114
1115 if (start < key.objectid) {
1116 ret = __add_to_free_space_tree(trans, fs_info,
1117 block_group,
1118 path2, start,
1119 key.objectid -
1120 start);
1121 if (ret)
1122 goto out_locked;
1123 }
1124 start = key.objectid;
1125 if (key.type == BTRFS_METADATA_ITEM_KEY)
1126 start += fs_info->nodesize;
1127 else
1128 start += key.offset;
1129 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1130 if (key.objectid != block_group->key.objectid)
1131 break;
1132 }
1133
1134 ret = btrfs_next_item(extent_root, path);
1135 if (ret < 0)
1136 goto out_locked;
1137 if (ret)
1138 break;
1139 }
1140 if (start < end) {
1141 ret = __add_to_free_space_tree(trans, fs_info, block_group,
1142 path2, start, end - start);
1143 if (ret)
1144 goto out_locked;
1145 }
1146
1147 ret = 0;
1148out_locked:
1149 mutex_unlock(&block_group->free_space_lock);
1150out:
1151 btrfs_free_path(path2);
1152 btrfs_free_path(path);
1153 return ret;
1154}
1155
1156int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1157{
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;
1163 int ret;
1164
1165 trans = btrfs_start_transaction(tree_root, 0);
1166 if (IS_ERR(trans))
1167 return PTR_ERR(trans);
1168
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);
1174 goto abort;
1175 }
1176 fs_info->free_space_root = free_space_root;
1177
1178 node = rb_first(&fs_info->block_group_cache_tree);
1179 while (node) {
1180 block_group = rb_entry(node, struct btrfs_block_group_cache,
1181 cache_node);
1182 ret = populate_free_space_tree(trans, fs_info, block_group);
1183 if (ret)
1184 goto abort;
1185 node = rb_next(node);
1186 }
1187
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);
1191
1192 ret = btrfs_commit_transaction(trans);
1193 if (ret)
1194 return ret;
1195
1196 return 0;
1197
1198abort:
1199 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1200 btrfs_abort_transaction(trans, ret);
1201 btrfs_end_transaction(trans);
1202 return ret;
1203}
1204
1205static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1206 struct btrfs_root *root)
1207{
1208 struct btrfs_path *path;
1209 struct btrfs_key key;
1210 int nr;
1211 int ret;
1212
1213 path = btrfs_alloc_path();
1214 if (!path)
1215 return -ENOMEM;
1216
1217 path->leave_spinning = 1;
1218
1219 key.objectid = 0;
1220 key.type = 0;
1221 key.offset = 0;
1222
1223 while (1) {
1224 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1225 if (ret < 0)
1226 goto out;
1227
1228 nr = btrfs_header_nritems(path->nodes[0]);
1229 if (!nr)
1230 break;
1231
1232 path->slots[0] = 0;
1233 ret = btrfs_del_items(trans, root, path, 0, nr);
1234 if (ret)
1235 goto out;
1236
1237 btrfs_release_path(path);
1238 }
1239
1240 ret = 0;
1241out:
1242 btrfs_free_path(path);
1243 return ret;
1244}
1245
1246int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
1247{
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;
1251 int ret;
1252
1253 trans = btrfs_start_transaction(tree_root, 0);
1254 if (IS_ERR(trans))
1255 return PTR_ERR(trans);
1256
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;
1260
1261 ret = clear_free_space_tree(trans, free_space_root);
1262 if (ret)
1263 goto abort;
1264
1265 ret = btrfs_del_root(trans, tree_root, &free_space_root->root_key);
1266 if (ret)
1267 goto abort;
1268
1269 list_del(&free_space_root->dirty_list);
1270
1271 btrfs_tree_lock(free_space_root->node);
1272 clean_tree_block(trans, 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,
1275 0, 1);
1276
1277 free_extent_buffer(free_space_root->node);
1278 free_extent_buffer(free_space_root->commit_root);
1279 kfree(free_space_root);
1280
1281 ret = btrfs_commit_transaction(trans);
1282 if (ret)
1283 return ret;
1284
1285 return 0;
1286
1287abort:
1288 btrfs_abort_transaction(trans, ret);
1289 btrfs_end_transaction(trans);
1290 return ret;
1291}
1292
1293static 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)
1297{
1298 u64 start, end;
1299 int ret;
1300
1301 start = block_group->key.objectid;
1302 end = block_group->key.objectid + block_group->key.offset;
1303
1304 block_group->needs_free_space = 0;
1305
1306 ret = add_new_free_space_info(trans, fs_info, block_group, path);
1307 if (ret)
1308 return ret;
1309
1310 return __add_to_free_space_tree(trans, fs_info, block_group, path,
1311 block_group->key.objectid,
1312 block_group->key.offset);
1313}
1314
1315int 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)
1318{
1319 struct btrfs_path *path = NULL;
1320 int ret = 0;
1321
1322 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1323 return 0;
1324
1325 mutex_lock(&block_group->free_space_lock);
1326 if (!block_group->needs_free_space)
1327 goto out;
1328
1329 path = btrfs_alloc_path();
1330 if (!path) {
1331 ret = -ENOMEM;
1332 goto out;
1333 }
1334
1335 ret = __add_block_group_free_space(trans, fs_info, block_group, path);
1336
1337out:
1338 btrfs_free_path(path);
1339 mutex_unlock(&block_group->free_space_lock);
1340 if (ret)
1341 btrfs_abort_transaction(trans, ret);
1342 return ret;
1343}
1344
1345int 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)
1348{
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;
1353 u64 start, end;
1354 int done = 0, nr;
1355 int ret;
1356
1357 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1358 return 0;
1359
1360 if (block_group->needs_free_space) {
1361 /* We never added this block group to the free space tree. */
1362 return 0;
1363 }
1364
1365 path = btrfs_alloc_path();
1366 if (!path) {
1367 ret = -ENOMEM;
1368 goto out;
1369 }
1370
1371 start = block_group->key.objectid;
1372 end = block_group->key.objectid + block_group->key.offset;
1373
1374 key.objectid = end - 1;
1375 key.type = (u8)-1;
1376 key.offset = (u64)-1;
1377
1378 while (!done) {
1379 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1380 if (ret)
1381 goto out;
1382
1383 leaf = path->nodes[0];
1384 nr = 0;
1385 path->slots[0]++;
1386 while (path->slots[0] > 0) {
1387 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1388
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);
1392 done = 1;
1393 nr++;
1394 path->slots[0]--;
1395 break;
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);
1401 nr++;
1402 path->slots[0]--;
1403 } else {
1404 ASSERT(0);
1405 }
1406 }
1407
1408 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1409 if (ret)
1410 goto out;
1411 btrfs_release_path(path);
1412 }
1413
1414 ret = 0;
1415out:
1416 btrfs_free_path(path);
1417 if (ret)
1418 btrfs_abort_transaction(trans, ret);
1419 return ret;
1420}
1421
1422static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1423 struct btrfs_path *path,
1424 u32 expected_extent_count)
1425{
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;
1433 u64 end, offset;
1434 u64 total_found = 0;
1435 u32 extent_count = 0;
1436 int ret;
1437
1438 block_group = caching_ctl->block_group;
1439 fs_info = block_group->fs_info;
1440 root = fs_info->free_space_root;
1441
1442 end = block_group->key.objectid + block_group->key.offset;
1443
1444 while (1) {
1445 ret = btrfs_next_item(root, path);
1446 if (ret < 0)
1447 goto out;
1448 if (ret)
1449 break;
1450
1451 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1452
1453 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1454 break;
1455
1456 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1457 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1458
1459 caching_ctl->progress = key.objectid;
1460
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,
1468 fs_info,
1469 extent_start,
1470 offset);
1471 if (total_found > CACHING_CTL_WAKE_UP) {
1472 total_found = 0;
1473 wake_up(&caching_ctl->wait);
1474 }
1475 extent_count++;
1476 }
1477 prev_bit = bit;
1478 offset += fs_info->sectorsize;
1479 }
1480 }
1481 if (prev_bit == 1) {
1482 total_found += add_new_free_space(block_group, fs_info,
1483 extent_start, end);
1484 extent_count++;
1485 }
1486
1487 if (extent_count != expected_extent_count) {
1488 btrfs_err(fs_info,
1489 "incorrect extent count for %llu; counted %u, expected %u",
1490 block_group->key.objectid, extent_count,
1491 expected_extent_count);
1492 ASSERT(0);
1493 ret = -EIO;
1494 goto out;
1495 }
1496
1497 caching_ctl->progress = (u64)-1;
1498
1499 ret = 0;
1500out:
1501 return ret;
1502}
1503
1504static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1505 struct btrfs_path *path,
1506 u32 expected_extent_count)
1507{
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;
1512 u64 end;
1513 u64 total_found = 0;
1514 u32 extent_count = 0;
1515 int ret;
1516
1517 block_group = caching_ctl->block_group;
1518 fs_info = block_group->fs_info;
1519 root = fs_info->free_space_root;
1520
1521 end = block_group->key.objectid + block_group->key.offset;
1522
1523 while (1) {
1524 ret = btrfs_next_item(root, path);
1525 if (ret < 0)
1526 goto out;
1527 if (ret)
1528 break;
1529
1530 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1531
1532 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1533 break;
1534
1535 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1536 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1537
1538 caching_ctl->progress = key.objectid;
1539
1540 total_found += add_new_free_space(block_group, fs_info,
1541 key.objectid,
1542 key.objectid + key.offset);
1543 if (total_found > CACHING_CTL_WAKE_UP) {
1544 total_found = 0;
1545 wake_up(&caching_ctl->wait);
1546 }
1547 extent_count++;
1548 }
1549
1550 if (extent_count != expected_extent_count) {
1551 btrfs_err(fs_info,
1552 "incorrect extent count for %llu; counted %u, expected %u",
1553 block_group->key.objectid, extent_count,
1554 expected_extent_count);
1555 ASSERT(0);
1556 ret = -EIO;
1557 goto out;
1558 }
1559
1560 caching_ctl->progress = (u64)-1;
1561
1562 ret = 0;
1563out:
1564 return ret;
1565}
1566
1567int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
1568{
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;
1574 int ret;
1575
1576 block_group = caching_ctl->block_group;
1577 fs_info = block_group->fs_info;
1578
1579 path = btrfs_alloc_path();
1580 if (!path)
1581 return -ENOMEM;
1582
1583 /*
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.
1586 */
1587 path->skip_locking = 1;
1588 path->search_commit_root = 1;
1589 path->reada = 1;
1590
1591 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
1592 if (IS_ERR(info)) {
1593 ret = PTR_ERR(info);
1594 goto out;
1595 }
1596 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
1597 flags = btrfs_free_space_flags(path->nodes[0], info);
1598
1599 /*
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
1602 * there.
1603 */
1604 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS)
1605 ret = load_free_space_bitmaps(caching_ctl, path, extent_count);
1606 else
1607 ret = load_free_space_extents(caching_ctl, path, extent_count);
1608
1609out:
1610 btrfs_free_path(path);
1611 return ret;
1612}