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