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Btrfs: fix xattr loss after power failure
[linux/fpc-iii.git] / fs / btrfs / free-space-tree.c
blob32a0f6cb55948aac654bc30e986adbeeaf5b451b
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2015 Facebook. All rights reserved.
4 */
5
6 #include <linux/kernel.h>
7 #include <linux/sched/mm.h>
8 #include "ctree.h"
9 #include "disk-io.h"
10 #include "locking.h"
11 #include "free-space-tree.h"
12 #include "transaction.h"
13
14 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
15 struct btrfs_fs_info *fs_info,
16 struct btrfs_block_group_cache *block_group,
17 struct btrfs_path *path);
18
19 void set_free_space_tree_thresholds(struct btrfs_block_group_cache *cache)
20 {
21 u32 bitmap_range;
22 size_t bitmap_size;
23 u64 num_bitmaps, total_bitmap_size;
24
25 /*
26 * We convert to bitmaps when the disk space required for using extents
27 * exceeds that required for using bitmaps.
28 */
29 bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
30 num_bitmaps = div_u64(cache->key.offset + bitmap_range - 1,
31 bitmap_range);
32 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
33 total_bitmap_size = num_bitmaps * bitmap_size;
34 cache->bitmap_high_thresh = div_u64(total_bitmap_size,
35 sizeof(struct btrfs_item));
36
37 /*
38 * We allow for a small buffer between the high threshold and low
39 * threshold to avoid thrashing back and forth between the two formats.
40 */
41 if (cache->bitmap_high_thresh > 100)
42 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
43 else
44 cache->bitmap_low_thresh = 0;
45 }
46
47 static int add_new_free_space_info(struct btrfs_trans_handle *trans,
48 struct btrfs_fs_info *fs_info,
49 struct btrfs_block_group_cache *block_group,
50 struct btrfs_path *path)
51 {
52 struct btrfs_root *root = fs_info->free_space_root;
53 struct btrfs_free_space_info *info;
54 struct btrfs_key key;
55 struct extent_buffer *leaf;
56 int ret;
57
58 key.objectid = block_group->key.objectid;
59 key.type = BTRFS_FREE_SPACE_INFO_KEY;
60 key.offset = block_group->key.offset;
61
62 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
63 if (ret)
64 goto out;
65
66 leaf = path->nodes[0];
67 info = btrfs_item_ptr(leaf, path->slots[0],
68 struct btrfs_free_space_info);
69 btrfs_set_free_space_extent_count(leaf, info, 0);
70 btrfs_set_free_space_flags(leaf, info, 0);
71 btrfs_mark_buffer_dirty(leaf);
72
73 ret = 0;
74 out:
75 btrfs_release_path(path);
76 return ret;
77 }
78
79 struct btrfs_free_space_info *
80 search_free_space_info(struct btrfs_trans_handle *trans,
81 struct btrfs_fs_info *fs_info,
82 struct btrfs_block_group_cache *block_group,
83 struct btrfs_path *path, int cow)
84 {
85 struct btrfs_root *root = fs_info->free_space_root;
86 struct btrfs_key key;
87 int ret;
88
89 key.objectid = block_group->key.objectid;
90 key.type = BTRFS_FREE_SPACE_INFO_KEY;
91 key.offset = block_group->key.offset;
92
93 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
94 if (ret < 0)
95 return ERR_PTR(ret);
96 if (ret != 0) {
97 btrfs_warn(fs_info, "missing free space info for %llu",
98 block_group->key.objectid);
99 ASSERT(0);
100 return ERR_PTR(-ENOENT);
101 }
102
103 return btrfs_item_ptr(path->nodes[0], path->slots[0],
104 struct btrfs_free_space_info);
105 }
106
107 /*
108 * btrfs_search_slot() but we're looking for the greatest key less than the
109 * passed key.
110 */
111 static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
112 struct btrfs_root *root,
113 struct btrfs_key *key, struct btrfs_path *p,
114 int ins_len, int cow)
115 {
116 int ret;
117
118 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
119 if (ret < 0)
120 return ret;
121
122 if (ret == 0) {
123 ASSERT(0);
124 return -EIO;
125 }
126
127 if (p->slots[0] == 0) {
128 ASSERT(0);
129 return -EIO;
130 }
131 p->slots[0]--;
132
133 return 0;
134 }
135
136 static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize)
137 {
138 return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
139 }
140
141 static u8 *alloc_bitmap(u32 bitmap_size)
142 {
143 u8 *ret;
144 unsigned int nofs_flag;
145
146 /*
147 * GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse
148 * into the filesystem as the free space bitmap can be modified in the
149 * critical section of a transaction commit.
150 *
151 * TODO: push the memalloc_nofs_{save,restore}() to the caller where we
152 * know that recursion is unsafe.
153 */
154 nofs_flag = memalloc_nofs_save();
155 ret = kvzalloc(bitmap_size, GFP_KERNEL);
156 memalloc_nofs_restore(nofs_flag);
157 return ret;
158 }
159
160 int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
161 struct btrfs_fs_info *fs_info,
162 struct btrfs_block_group_cache *block_group,
163 struct btrfs_path *path)
164 {
165 struct btrfs_root *root = fs_info->free_space_root;
166 struct btrfs_free_space_info *info;
167 struct btrfs_key key, found_key;
168 struct extent_buffer *leaf;
169 u8 *bitmap, *bitmap_cursor;
170 u64 start, end;
171 u64 bitmap_range, i;
172 u32 bitmap_size, flags, expected_extent_count;
173 u32 extent_count = 0;
174 int done = 0, nr;
175 int ret;
176
177 bitmap_size = free_space_bitmap_size(block_group->key.offset,
178 fs_info->sectorsize);
179 bitmap = alloc_bitmap(bitmap_size);
180 if (!bitmap) {
181 ret = -ENOMEM;
182 goto out;
183 }
184
185 start = block_group->key.objectid;
186 end = block_group->key.objectid + block_group->key.offset;
187
188 key.objectid = end - 1;
189 key.type = (u8)-1;
190 key.offset = (u64)-1;
191
192 while (!done) {
193 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
194 if (ret)
195 goto out;
196
197 leaf = path->nodes[0];
198 nr = 0;
199 path->slots[0]++;
200 while (path->slots[0] > 0) {
201 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
202
203 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
204 ASSERT(found_key.objectid == block_group->key.objectid);
205 ASSERT(found_key.offset == block_group->key.offset);
206 done = 1;
207 break;
208 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
209 u64 first, last;
210
211 ASSERT(found_key.objectid >= start);
212 ASSERT(found_key.objectid < end);
213 ASSERT(found_key.objectid + found_key.offset <= end);
214
215 first = div_u64(found_key.objectid - start,
216 fs_info->sectorsize);
217 last = div_u64(found_key.objectid + found_key.offset - start,
218 fs_info->sectorsize);
219 le_bitmap_set(bitmap, first, last - first);
220
221 extent_count++;
222 nr++;
223 path->slots[0]--;
224 } else {
225 ASSERT(0);
226 }
227 }
228
229 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
230 if (ret)
231 goto out;
232 btrfs_release_path(path);
233 }
234
235 info = search_free_space_info(trans, fs_info, block_group, path, 1);
236 if (IS_ERR(info)) {
237 ret = PTR_ERR(info);
238 goto out;
239 }
240 leaf = path->nodes[0];
241 flags = btrfs_free_space_flags(leaf, info);
242 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
243 btrfs_set_free_space_flags(leaf, info, flags);
244 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
245 btrfs_mark_buffer_dirty(leaf);
246 btrfs_release_path(path);
247
248 if (extent_count != expected_extent_count) {
249 btrfs_err(fs_info,
250 "incorrect extent count for %llu; counted %u, expected %u",
251 block_group->key.objectid, extent_count,
252 expected_extent_count);
253 ASSERT(0);
254 ret = -EIO;
255 goto out;
256 }
257
258 bitmap_cursor = bitmap;
259 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
260 i = start;
261 while (i < end) {
262 unsigned long ptr;
263 u64 extent_size;
264 u32 data_size;
265
266 extent_size = min(end - i, bitmap_range);
267 data_size = free_space_bitmap_size(extent_size,
268 fs_info->sectorsize);
269
270 key.objectid = i;
271 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
272 key.offset = extent_size;
273
274 ret = btrfs_insert_empty_item(trans, root, path, &key,
275 data_size);
276 if (ret)
277 goto out;
278
279 leaf = path->nodes[0];
280 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
281 write_extent_buffer(leaf, bitmap_cursor, ptr,
282 data_size);
283 btrfs_mark_buffer_dirty(leaf);
284 btrfs_release_path(path);
285
286 i += extent_size;
287 bitmap_cursor += data_size;
288 }
289
290 ret = 0;
291 out:
292 kvfree(bitmap);
293 if (ret)
294 btrfs_abort_transaction(trans, ret);
295 return ret;
296 }
297
298 int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
299 struct btrfs_fs_info *fs_info,
300 struct btrfs_block_group_cache *block_group,
301 struct btrfs_path *path)
302 {
303 struct btrfs_root *root = fs_info->free_space_root;
304 struct btrfs_free_space_info *info;
305 struct btrfs_key key, found_key;
306 struct extent_buffer *leaf;
307 u8 *bitmap;
308 u64 start, end;
309 /* Initialize to silence GCC. */
310 u64 extent_start = 0;
311 u64 offset;
312 u32 bitmap_size, flags, expected_extent_count;
313 int prev_bit = 0, bit, bitnr;
314 u32 extent_count = 0;
315 int done = 0, nr;
316 int ret;
317
318 bitmap_size = free_space_bitmap_size(block_group->key.offset,
319 fs_info->sectorsize);
320 bitmap = alloc_bitmap(bitmap_size);
321 if (!bitmap) {
322 ret = -ENOMEM;
323 goto out;
324 }
325
326 start = block_group->key.objectid;
327 end = block_group->key.objectid + block_group->key.offset;
328
329 key.objectid = end - 1;
330 key.type = (u8)-1;
331 key.offset = (u64)-1;
332
333 while (!done) {
334 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
335 if (ret)
336 goto out;
337
338 leaf = path->nodes[0];
339 nr = 0;
340 path->slots[0]++;
341 while (path->slots[0] > 0) {
342 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
343
344 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
345 ASSERT(found_key.objectid == block_group->key.objectid);
346 ASSERT(found_key.offset == block_group->key.offset);
347 done = 1;
348 break;
349 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
350 unsigned long ptr;
351 u8 *bitmap_cursor;
352 u32 bitmap_pos, data_size;
353
354 ASSERT(found_key.objectid >= start);
355 ASSERT(found_key.objectid < end);
356 ASSERT(found_key.objectid + found_key.offset <= end);
357
358 bitmap_pos = div_u64(found_key.objectid - start,
359 fs_info->sectorsize *
360 BITS_PER_BYTE);
361 bitmap_cursor = bitmap + bitmap_pos;
362 data_size = free_space_bitmap_size(found_key.offset,
363 fs_info->sectorsize);
364
365 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
366 read_extent_buffer(leaf, bitmap_cursor, ptr,
367 data_size);
368
369 nr++;
370 path->slots[0]--;
371 } else {
372 ASSERT(0);
373 }
374 }
375
376 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
377 if (ret)
378 goto out;
379 btrfs_release_path(path);
380 }
381
382 info = search_free_space_info(trans, fs_info, block_group, path, 1);
383 if (IS_ERR(info)) {
384 ret = PTR_ERR(info);
385 goto out;
386 }
387 leaf = path->nodes[0];
388 flags = btrfs_free_space_flags(leaf, info);
389 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
390 btrfs_set_free_space_flags(leaf, info, flags);
391 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
392 btrfs_mark_buffer_dirty(leaf);
393 btrfs_release_path(path);
394
395 offset = start;
396 bitnr = 0;
397 while (offset < end) {
398 bit = !!le_test_bit(bitnr, bitmap);
399 if (prev_bit == 0 && bit == 1) {
400 extent_start = offset;
401 } else if (prev_bit == 1 && bit == 0) {
402 key.objectid = extent_start;
403 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
404 key.offset = offset - extent_start;
405
406 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
407 if (ret)
408 goto out;
409 btrfs_release_path(path);
410
411 extent_count++;
412 }
413 prev_bit = bit;
414 offset += fs_info->sectorsize;
415 bitnr++;
416 }
417 if (prev_bit == 1) {
418 key.objectid = extent_start;
419 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
420 key.offset = end - extent_start;
421
422 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
423 if (ret)
424 goto out;
425 btrfs_release_path(path);
426
427 extent_count++;
428 }
429
430 if (extent_count != expected_extent_count) {
431 btrfs_err(fs_info,
432 "incorrect extent count for %llu; counted %u, expected %u",
433 block_group->key.objectid, extent_count,
434 expected_extent_count);
435 ASSERT(0);
436 ret = -EIO;
437 goto out;
438 }
439
440 ret = 0;
441 out:
442 kvfree(bitmap);
443 if (ret)
444 btrfs_abort_transaction(trans, ret);
445 return ret;
446 }
447
448 static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
449 struct btrfs_fs_info *fs_info,
450 struct btrfs_block_group_cache *block_group,
451 struct btrfs_path *path,
452 int new_extents)
453 {
454 struct btrfs_free_space_info *info;
455 u32 flags;
456 u32 extent_count;
457 int ret = 0;
458
459 if (new_extents == 0)
460 return 0;
461
462 info = search_free_space_info(trans, fs_info, block_group, path, 1);
463 if (IS_ERR(info)) {
464 ret = PTR_ERR(info);
465 goto out;
466 }
467 flags = btrfs_free_space_flags(path->nodes[0], info);
468 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
469
470 extent_count += new_extents;
471 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
472 btrfs_mark_buffer_dirty(path->nodes[0]);
473 btrfs_release_path(path);
474
475 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
476 extent_count > block_group->bitmap_high_thresh) {
477 ret = convert_free_space_to_bitmaps(trans, fs_info, block_group,
478 path);
479 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
480 extent_count < block_group->bitmap_low_thresh) {
481 ret = convert_free_space_to_extents(trans, fs_info, block_group,
482 path);
483 }
484
485 out:
486 return ret;
487 }
488
489 int free_space_test_bit(struct btrfs_block_group_cache *block_group,
490 struct btrfs_path *path, u64 offset)
491 {
492 struct extent_buffer *leaf;
493 struct btrfs_key key;
494 u64 found_start, found_end;
495 unsigned long ptr, i;
496
497 leaf = path->nodes[0];
498 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
499 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
500
501 found_start = key.objectid;
502 found_end = key.objectid + key.offset;
503 ASSERT(offset >= found_start && offset < found_end);
504
505 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
506 i = div_u64(offset - found_start,
507 block_group->fs_info->sectorsize);
508 return !!extent_buffer_test_bit(leaf, ptr, i);
509 }
510
511 static void free_space_set_bits(struct btrfs_block_group_cache *block_group,
512 struct btrfs_path *path, u64 *start, u64 *size,
513 int bit)
514 {
515 struct btrfs_fs_info *fs_info = block_group->fs_info;
516 struct extent_buffer *leaf;
517 struct btrfs_key key;
518 u64 end = *start + *size;
519 u64 found_start, found_end;
520 unsigned long ptr, first, last;
521
522 leaf = path->nodes[0];
523 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
524 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
525
526 found_start = key.objectid;
527 found_end = key.objectid + key.offset;
528 ASSERT(*start >= found_start && *start < found_end);
529 ASSERT(end > found_start);
530
531 if (end > found_end)
532 end = found_end;
533
534 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
535 first = div_u64(*start - found_start, fs_info->sectorsize);
536 last = div_u64(end - found_start, fs_info->sectorsize);
537 if (bit)
538 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
539 else
540 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
541 btrfs_mark_buffer_dirty(leaf);
542
543 *size -= end - *start;
544 *start = end;
545 }
546
547 /*
548 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
549 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
550 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
551 * looking for.
552 */
553 static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
554 struct btrfs_root *root, struct btrfs_path *p)
555 {
556 struct btrfs_key key;
557
558 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
559 p->slots[0]++;
560 return 0;
561 }
562
563 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
564 btrfs_release_path(p);
565
566 key.objectid += key.offset;
567 key.type = (u8)-1;
568 key.offset = (u64)-1;
569
570 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
571 }
572
573 /*
574 * If remove is 1, then we are removing free space, thus clearing bits in the
575 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
576 * the bitmap.
577 */
578 static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
579 struct btrfs_fs_info *fs_info,
580 struct btrfs_block_group_cache *block_group,
581 struct btrfs_path *path,
582 u64 start, u64 size, int remove)
583 {
584 struct btrfs_root *root = fs_info->free_space_root;
585 struct btrfs_key key;
586 u64 end = start + size;
587 u64 cur_start, cur_size;
588 int prev_bit, next_bit;
589 int new_extents;
590 int ret;
591
592 /*
593 * Read the bit for the block immediately before the extent of space if
594 * that block is within the block group.
595 */
596 if (start > block_group->key.objectid) {
597 u64 prev_block = start - block_group->fs_info->sectorsize;
598
599 key.objectid = prev_block;
600 key.type = (u8)-1;
601 key.offset = (u64)-1;
602
603 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
604 if (ret)
605 goto out;
606
607 prev_bit = free_space_test_bit(block_group, path, prev_block);
608
609 /* The previous block may have been in the previous bitmap. */
610 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
611 if (start >= key.objectid + key.offset) {
612 ret = free_space_next_bitmap(trans, root, path);
613 if (ret)
614 goto out;
615 }
616 } else {
617 key.objectid = start;
618 key.type = (u8)-1;
619 key.offset = (u64)-1;
620
621 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
622 if (ret)
623 goto out;
624
625 prev_bit = -1;
626 }
627
628 /*
629 * Iterate over all of the bitmaps overlapped by the extent of space,
630 * clearing/setting bits as required.
631 */
632 cur_start = start;
633 cur_size = size;
634 while (1) {
635 free_space_set_bits(block_group, path, &cur_start, &cur_size,
636 !remove);
637 if (cur_size == 0)
638 break;
639 ret = free_space_next_bitmap(trans, root, path);
640 if (ret)
641 goto out;
642 }
643
644 /*
645 * Read the bit for the block immediately after the extent of space if
646 * that block is within the block group.
647 */
648 if (end < block_group->key.objectid + block_group->key.offset) {
649 /* The next block may be in the next bitmap. */
650 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
651 if (end >= key.objectid + key.offset) {
652 ret = free_space_next_bitmap(trans, root, path);
653 if (ret)
654 goto out;
655 }
656
657 next_bit = free_space_test_bit(block_group, path, end);
658 } else {
659 next_bit = -1;
660 }
661
662 if (remove) {
663 new_extents = -1;
664 if (prev_bit == 1) {
665 /* Leftover on the left. */
666 new_extents++;
667 }
668 if (next_bit == 1) {
669 /* Leftover on the right. */
670 new_extents++;
671 }
672 } else {
673 new_extents = 1;
674 if (prev_bit == 1) {
675 /* Merging with neighbor on the left. */
676 new_extents--;
677 }
678 if (next_bit == 1) {
679 /* Merging with neighbor on the right. */
680 new_extents--;
681 }
682 }
683
684 btrfs_release_path(path);
685 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
686 new_extents);
687
688 out:
689 return ret;
690 }
691
692 static int remove_free_space_extent(struct btrfs_trans_handle *trans,
693 struct btrfs_fs_info *fs_info,
694 struct btrfs_block_group_cache *block_group,
695 struct btrfs_path *path,
696 u64 start, u64 size)
697 {
698 struct btrfs_root *root = fs_info->free_space_root;
699 struct btrfs_key key;
700 u64 found_start, found_end;
701 u64 end = start + size;
702 int new_extents = -1;
703 int ret;
704
705 key.objectid = start;
706 key.type = (u8)-1;
707 key.offset = (u64)-1;
708
709 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
710 if (ret)
711 goto out;
712
713 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
714
715 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
716
717 found_start = key.objectid;
718 found_end = key.objectid + key.offset;
719 ASSERT(start >= found_start && end <= found_end);
720
721 /*
722 * Okay, now that we've found the free space extent which contains the
723 * free space that we are removing, there are four cases:
724 *
725 * 1. We're using the whole extent: delete the key we found and
726 * decrement the free space extent count.
727 * 2. We are using part of the extent starting at the beginning: delete
728 * the key we found and insert a new key representing the leftover at
729 * the end. There is no net change in the number of extents.
730 * 3. We are using part of the extent ending at the end: delete the key
731 * we found and insert a new key representing the leftover at the
732 * beginning. There is no net change in the number of extents.
733 * 4. We are using part of the extent in the middle: delete the key we
734 * found and insert two new keys representing the leftovers on each
735 * side. Where we used to have one extent, we now have two, so increment
736 * the extent count. We may need to convert the block group to bitmaps
737 * as a result.
738 */
739
740 /* Delete the existing key (cases 1-4). */
741 ret = btrfs_del_item(trans, root, path);
742 if (ret)
743 goto out;
744
745 /* Add a key for leftovers at the beginning (cases 3 and 4). */
746 if (start > found_start) {
747 key.objectid = found_start;
748 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
749 key.offset = start - found_start;
750
751 btrfs_release_path(path);
752 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
753 if (ret)
754 goto out;
755 new_extents++;
756 }
757
758 /* Add a key for leftovers at the end (cases 2 and 4). */
759 if (end < found_end) {
760 key.objectid = end;
761 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
762 key.offset = found_end - end;
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 btrfs_release_path(path);
772 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
773 new_extents);
774
775 out:
776 return ret;
777 }
778
779 int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
780 struct btrfs_fs_info *fs_info,
781 struct btrfs_block_group_cache *block_group,
782 struct btrfs_path *path, u64 start, u64 size)
783 {
784 struct btrfs_free_space_info *info;
785 u32 flags;
786 int ret;
787
788 if (block_group->needs_free_space) {
789 ret = __add_block_group_free_space(trans, fs_info, block_group,
790 path);
791 if (ret)
792 return ret;
793 }
794
795 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
796 if (IS_ERR(info))
797 return PTR_ERR(info);
798 flags = btrfs_free_space_flags(path->nodes[0], info);
799 btrfs_release_path(path);
800
801 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
802 return modify_free_space_bitmap(trans, fs_info, block_group,
803 path, start, size, 1);
804 } else {
805 return remove_free_space_extent(trans, fs_info, block_group,
806 path, start, size);
807 }
808 }
809
810 int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
811 struct btrfs_fs_info *fs_info,
812 u64 start, u64 size)
813 {
814 struct btrfs_block_group_cache *block_group;
815 struct btrfs_path *path;
816 int ret;
817
818 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
819 return 0;
820
821 path = btrfs_alloc_path();
822 if (!path) {
823 ret = -ENOMEM;
824 goto out;
825 }
826
827 block_group = btrfs_lookup_block_group(fs_info, start);
828 if (!block_group) {
829 ASSERT(0);
830 ret = -ENOENT;
831 goto out;
832 }
833
834 mutex_lock(&block_group->free_space_lock);
835 ret = __remove_from_free_space_tree(trans, fs_info, block_group, path,
836 start, size);
837 mutex_unlock(&block_group->free_space_lock);
838
839 btrfs_put_block_group(block_group);
840 out:
841 btrfs_free_path(path);
842 if (ret)
843 btrfs_abort_transaction(trans, ret);
844 return ret;
845 }
846
847 static int add_free_space_extent(struct btrfs_trans_handle *trans,
848 struct btrfs_fs_info *fs_info,
849 struct btrfs_block_group_cache *block_group,
850 struct btrfs_path *path,
851 u64 start, u64 size)
852 {
853 struct btrfs_root *root = fs_info->free_space_root;
854 struct btrfs_key key, new_key;
855 u64 found_start, found_end;
856 u64 end = start + size;
857 int new_extents = 1;
858 int ret;
859
860 /*
861 * We are adding a new extent of free space, but we need to merge
862 * extents. There are four cases here:
863 *
864 * 1. The new extent does not have any immediate neighbors to merge
865 * with: add the new key and increment the free space extent count. We
866 * may need to convert the block group to bitmaps as a result.
867 * 2. The new extent has an immediate neighbor before it: remove the
868 * previous key and insert a new key combining both of them. There is no
869 * net change in the number of extents.
870 * 3. The new extent has an immediate neighbor after it: remove the next
871 * key and insert a new key combining both of them. There is no net
872 * change in the number of extents.
873 * 4. The new extent has immediate neighbors on both sides: remove both
874 * of the keys and insert a new key combining all of them. Where we used
875 * to have two extents, we now have one, so decrement the extent count.
876 */
877
878 new_key.objectid = start;
879 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
880 new_key.offset = size;
881
882 /* Search for a neighbor on the left. */
883 if (start == block_group->key.objectid)
884 goto right;
885 key.objectid = start - 1;
886 key.type = (u8)-1;
887 key.offset = (u64)-1;
888
889 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
890 if (ret)
891 goto out;
892
893 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
894
895 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
896 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
897 btrfs_release_path(path);
898 goto right;
899 }
900
901 found_start = key.objectid;
902 found_end = key.objectid + key.offset;
903 ASSERT(found_start >= block_group->key.objectid &&
904 found_end > block_group->key.objectid);
905 ASSERT(found_start < start && found_end <= start);
906
907 /*
908 * Delete the neighbor on the left and absorb it into the new key (cases
909 * 2 and 4).
910 */
911 if (found_end == start) {
912 ret = btrfs_del_item(trans, root, path);
913 if (ret)
914 goto out;
915 new_key.objectid = found_start;
916 new_key.offset += key.offset;
917 new_extents--;
918 }
919 btrfs_release_path(path);
920
921 right:
922 /* Search for a neighbor on the right. */
923 if (end == block_group->key.objectid + block_group->key.offset)
924 goto insert;
925 key.objectid = end;
926 key.type = (u8)-1;
927 key.offset = (u64)-1;
928
929 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
930 if (ret)
931 goto out;
932
933 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
934
935 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
936 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
937 btrfs_release_path(path);
938 goto insert;
939 }
940
941 found_start = key.objectid;
942 found_end = key.objectid + key.offset;
943 ASSERT(found_start >= block_group->key.objectid &&
944 found_end > block_group->key.objectid);
945 ASSERT((found_start < start && found_end <= start) ||
946 (found_start >= end && found_end > end));
947
948 /*
949 * Delete the neighbor on the right and absorb it into the new key
950 * (cases 3 and 4).
951 */
952 if (found_start == end) {
953 ret = btrfs_del_item(trans, root, path);
954 if (ret)
955 goto out;
956 new_key.offset += key.offset;
957 new_extents--;
958 }
959 btrfs_release_path(path);
960
961 insert:
962 /* Insert the new key (cases 1-4). */
963 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
964 if (ret)
965 goto out;
966
967 btrfs_release_path(path);
968 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
969 new_extents);
970
971 out:
972 return ret;
973 }
974
975 int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
976 struct btrfs_fs_info *fs_info,
977 struct btrfs_block_group_cache *block_group,
978 struct btrfs_path *path, u64 start, u64 size)
979 {
980 struct btrfs_free_space_info *info;
981 u32 flags;
982 int ret;
983
984 if (block_group->needs_free_space) {
985 ret = __add_block_group_free_space(trans, fs_info, block_group,
986 path);
987 if (ret)
988 return ret;
989 }
990
991 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
992 if (IS_ERR(info))
993 return PTR_ERR(info);
994 flags = btrfs_free_space_flags(path->nodes[0], info);
995 btrfs_release_path(path);
996
997 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
998 return modify_free_space_bitmap(trans, fs_info, block_group,
999 path, start, size, 0);
1000 } else {
1001 return add_free_space_extent(trans, fs_info, block_group, path,
1002 start, size);
1003 }
1004 }
1005
1006 int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1007 struct btrfs_fs_info *fs_info,
1008 u64 start, u64 size)
1009 {
1010 struct btrfs_block_group_cache *block_group;
1011 struct btrfs_path *path;
1012 int ret;
1013
1014 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1015 return 0;
1016
1017 path = btrfs_alloc_path();
1018 if (!path) {
1019 ret = -ENOMEM;
1020 goto out;
1021 }
1022
1023 block_group = btrfs_lookup_block_group(fs_info, start);
1024 if (!block_group) {
1025 ASSERT(0);
1026 ret = -ENOENT;
1027 goto out;
1028 }
1029
1030 mutex_lock(&block_group->free_space_lock);
1031 ret = __add_to_free_space_tree(trans, fs_info, block_group, path, start,
1032 size);
1033 mutex_unlock(&block_group->free_space_lock);
1034
1035 btrfs_put_block_group(block_group);
1036 out:
1037 btrfs_free_path(path);
1038 if (ret)
1039 btrfs_abort_transaction(trans, ret);
1040 return ret;
1041 }
1042
1043 /*
1044 * Populate the free space tree by walking the extent tree. Operations on the
1045 * extent tree that happen as a result of writes to the free space tree will go
1046 * through the normal add/remove hooks.
1047 */
1048 static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1049 struct btrfs_fs_info *fs_info,
1050 struct btrfs_block_group_cache *block_group)
1051 {
1052 struct btrfs_root *extent_root = fs_info->extent_root;
1053 struct btrfs_path *path, *path2;
1054 struct btrfs_key key;
1055 u64 start, end;
1056 int ret;
1057
1058 path = btrfs_alloc_path();
1059 if (!path)
1060 return -ENOMEM;
1061 path->reada = READA_FORWARD;
1062
1063 path2 = btrfs_alloc_path();
1064 if (!path2) {
1065 btrfs_free_path(path);
1066 return -ENOMEM;
1067 }
1068
1069 ret = add_new_free_space_info(trans, fs_info, block_group, path2);
1070 if (ret)
1071 goto out;
1072
1073 mutex_lock(&block_group->free_space_lock);
1074
1075 /*
1076 * Iterate through all of the extent and metadata items in this block
1077 * group, adding the free space between them and the free space at the
1078 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1079 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1080 * contained in.
1081 */
1082 key.objectid = block_group->key.objectid;
1083 key.type = BTRFS_EXTENT_ITEM_KEY;
1084 key.offset = 0;
1085
1086 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1087 if (ret < 0)
1088 goto out_locked;
1089 ASSERT(ret == 0);
1090
1091 start = block_group->key.objectid;
1092 end = block_group->key.objectid + block_group->key.offset;
1093 while (1) {
1094 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1095
1096 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1097 key.type == BTRFS_METADATA_ITEM_KEY) {
1098 if (key.objectid >= end)
1099 break;
1100
1101 if (start < key.objectid) {
1102 ret = __add_to_free_space_tree(trans, fs_info,
1103 block_group,
1104 path2, start,
1105 key.objectid -
1106 start);
1107 if (ret)
1108 goto out_locked;
1109 }
1110 start = key.objectid;
1111 if (key.type == BTRFS_METADATA_ITEM_KEY)
1112 start += fs_info->nodesize;
1113 else
1114 start += key.offset;
1115 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1116 if (key.objectid != block_group->key.objectid)
1117 break;
1118 }
1119
1120 ret = btrfs_next_item(extent_root, path);
1121 if (ret < 0)
1122 goto out_locked;
1123 if (ret)
1124 break;
1125 }
1126 if (start < end) {
1127 ret = __add_to_free_space_tree(trans, fs_info, block_group,
1128 path2, start, end - start);
1129 if (ret)
1130 goto out_locked;
1131 }
1132
1133 ret = 0;
1134 out_locked:
1135 mutex_unlock(&block_group->free_space_lock);
1136 out:
1137 btrfs_free_path(path2);
1138 btrfs_free_path(path);
1139 return ret;
1140 }
1141
1142 int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1143 {
1144 struct btrfs_trans_handle *trans;
1145 struct btrfs_root *tree_root = fs_info->tree_root;
1146 struct btrfs_root *free_space_root;
1147 struct btrfs_block_group_cache *block_group;
1148 struct rb_node *node;
1149 int ret;
1150
1151 trans = btrfs_start_transaction(tree_root, 0);
1152 if (IS_ERR(trans))
1153 return PTR_ERR(trans);
1154
1155 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1156 free_space_root = btrfs_create_tree(trans, fs_info,
1157 BTRFS_FREE_SPACE_TREE_OBJECTID);
1158 if (IS_ERR(free_space_root)) {
1159 ret = PTR_ERR(free_space_root);
1160 goto abort;
1161 }
1162 fs_info->free_space_root = free_space_root;
1163
1164 node = rb_first(&fs_info->block_group_cache_tree);
1165 while (node) {
1166 block_group = rb_entry(node, struct btrfs_block_group_cache,
1167 cache_node);
1168 ret = populate_free_space_tree(trans, fs_info, block_group);
1169 if (ret)
1170 goto abort;
1171 node = rb_next(node);
1172 }
1173
1174 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1175 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1176 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1177
1178 return btrfs_commit_transaction(trans);
1179
1180 abort:
1181 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1182 btrfs_abort_transaction(trans, ret);
1183 btrfs_end_transaction(trans);
1184 return ret;
1185 }
1186
1187 static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1188 struct btrfs_root *root)
1189 {
1190 struct btrfs_path *path;
1191 struct btrfs_key key;
1192 int nr;
1193 int ret;
1194
1195 path = btrfs_alloc_path();
1196 if (!path)
1197 return -ENOMEM;
1198
1199 path->leave_spinning = 1;
1200
1201 key.objectid = 0;
1202 key.type = 0;
1203 key.offset = 0;
1204
1205 while (1) {
1206 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1207 if (ret < 0)
1208 goto out;
1209
1210 nr = btrfs_header_nritems(path->nodes[0]);
1211 if (!nr)
1212 break;
1213
1214 path->slots[0] = 0;
1215 ret = btrfs_del_items(trans, root, path, 0, nr);
1216 if (ret)
1217 goto out;
1218
1219 btrfs_release_path(path);
1220 }
1221
1222 ret = 0;
1223 out:
1224 btrfs_free_path(path);
1225 return ret;
1226 }
1227
1228 int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
1229 {
1230 struct btrfs_trans_handle *trans;
1231 struct btrfs_root *tree_root = fs_info->tree_root;
1232 struct btrfs_root *free_space_root = fs_info->free_space_root;
1233 int ret;
1234
1235 trans = btrfs_start_transaction(tree_root, 0);
1236 if (IS_ERR(trans))
1237 return PTR_ERR(trans);
1238
1239 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1240 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1241 fs_info->free_space_root = NULL;
1242
1243 ret = clear_free_space_tree(trans, free_space_root);
1244 if (ret)
1245 goto abort;
1246
1247 ret = btrfs_del_root(trans, fs_info, &free_space_root->root_key);
1248 if (ret)
1249 goto abort;
1250
1251 list_del(&free_space_root->dirty_list);
1252
1253 btrfs_tree_lock(free_space_root->node);
1254 clean_tree_block(fs_info, free_space_root->node);
1255 btrfs_tree_unlock(free_space_root->node);
1256 btrfs_free_tree_block(trans, free_space_root, free_space_root->node,
1257 0, 1);
1258
1259 free_extent_buffer(free_space_root->node);
1260 free_extent_buffer(free_space_root->commit_root);
1261 kfree(free_space_root);
1262
1263 return btrfs_commit_transaction(trans);
1264
1265 abort:
1266 btrfs_abort_transaction(trans, ret);
1267 btrfs_end_transaction(trans);
1268 return ret;
1269 }
1270
1271 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
1272 struct btrfs_fs_info *fs_info,
1273 struct btrfs_block_group_cache *block_group,
1274 struct btrfs_path *path)
1275 {
1276 int ret;
1277
1278 block_group->needs_free_space = 0;
1279
1280 ret = add_new_free_space_info(trans, fs_info, block_group, path);
1281 if (ret)
1282 return ret;
1283
1284 return __add_to_free_space_tree(trans, fs_info, block_group, path,
1285 block_group->key.objectid,
1286 block_group->key.offset);
1287 }
1288
1289 int add_block_group_free_space(struct btrfs_trans_handle *trans,
1290 struct btrfs_fs_info *fs_info,
1291 struct btrfs_block_group_cache *block_group)
1292 {
1293 struct btrfs_path *path = NULL;
1294 int ret = 0;
1295
1296 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1297 return 0;
1298
1299 mutex_lock(&block_group->free_space_lock);
1300 if (!block_group->needs_free_space)
1301 goto out;
1302
1303 path = btrfs_alloc_path();
1304 if (!path) {
1305 ret = -ENOMEM;
1306 goto out;
1307 }
1308
1309 ret = __add_block_group_free_space(trans, fs_info, block_group, path);
1310
1311 out:
1312 btrfs_free_path(path);
1313 mutex_unlock(&block_group->free_space_lock);
1314 if (ret)
1315 btrfs_abort_transaction(trans, ret);
1316 return ret;
1317 }
1318
1319 int remove_block_group_free_space(struct btrfs_trans_handle *trans,
1320 struct btrfs_fs_info *fs_info,
1321 struct btrfs_block_group_cache *block_group)
1322 {
1323 struct btrfs_root *root = fs_info->free_space_root;
1324 struct btrfs_path *path;
1325 struct btrfs_key key, found_key;
1326 struct extent_buffer *leaf;
1327 u64 start, end;
1328 int done = 0, nr;
1329 int ret;
1330
1331 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1332 return 0;
1333
1334 if (block_group->needs_free_space) {
1335 /* We never added this block group to the free space tree. */
1336 return 0;
1337 }
1338
1339 path = btrfs_alloc_path();
1340 if (!path) {
1341 ret = -ENOMEM;
1342 goto out;
1343 }
1344
1345 start = block_group->key.objectid;
1346 end = block_group->key.objectid + block_group->key.offset;
1347
1348 key.objectid = end - 1;
1349 key.type = (u8)-1;
1350 key.offset = (u64)-1;
1351
1352 while (!done) {
1353 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1354 if (ret)
1355 goto out;
1356
1357 leaf = path->nodes[0];
1358 nr = 0;
1359 path->slots[0]++;
1360 while (path->slots[0] > 0) {
1361 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1362
1363 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
1364 ASSERT(found_key.objectid == block_group->key.objectid);
1365 ASSERT(found_key.offset == block_group->key.offset);
1366 done = 1;
1367 nr++;
1368 path->slots[0]--;
1369 break;
1370 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY ||
1371 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
1372 ASSERT(found_key.objectid >= start);
1373 ASSERT(found_key.objectid < end);
1374 ASSERT(found_key.objectid + found_key.offset <= end);
1375 nr++;
1376 path->slots[0]--;
1377 } else {
1378 ASSERT(0);
1379 }
1380 }
1381
1382 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1383 if (ret)
1384 goto out;
1385 btrfs_release_path(path);
1386 }
1387
1388 ret = 0;
1389 out:
1390 btrfs_free_path(path);
1391 if (ret)
1392 btrfs_abort_transaction(trans, ret);
1393 return ret;
1394 }
1395
1396 static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1397 struct btrfs_path *path,
1398 u32 expected_extent_count)
1399 {
1400 struct btrfs_block_group_cache *block_group;
1401 struct btrfs_fs_info *fs_info;
1402 struct btrfs_root *root;
1403 struct btrfs_key key;
1404 int prev_bit = 0, bit;
1405 /* Initialize to silence GCC. */
1406 u64 extent_start = 0;
1407 u64 end, offset;
1408 u64 total_found = 0;
1409 u32 extent_count = 0;
1410 int ret;
1411
1412 block_group = caching_ctl->block_group;
1413 fs_info = block_group->fs_info;
1414 root = fs_info->free_space_root;
1415
1416 end = block_group->key.objectid + block_group->key.offset;
1417
1418 while (1) {
1419 ret = btrfs_next_item(root, path);
1420 if (ret < 0)
1421 goto out;
1422 if (ret)
1423 break;
1424
1425 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1426
1427 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1428 break;
1429
1430 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1431 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1432
1433 caching_ctl->progress = key.objectid;
1434
1435 offset = key.objectid;
1436 while (offset < key.objectid + key.offset) {
1437 bit = free_space_test_bit(block_group, path, offset);
1438 if (prev_bit == 0 && bit == 1) {
1439 extent_start = offset;
1440 } else if (prev_bit == 1 && bit == 0) {
1441 total_found += add_new_free_space(block_group,
1442 fs_info,
1443 extent_start,
1444 offset);
1445 if (total_found > CACHING_CTL_WAKE_UP) {
1446 total_found = 0;
1447 wake_up(&caching_ctl->wait);
1448 }
1449 extent_count++;
1450 }
1451 prev_bit = bit;
1452 offset += fs_info->sectorsize;
1453 }
1454 }
1455 if (prev_bit == 1) {
1456 total_found += add_new_free_space(block_group, fs_info,
1457 extent_start, end);
1458 extent_count++;
1459 }
1460
1461 if (extent_count != expected_extent_count) {
1462 btrfs_err(fs_info,
1463 "incorrect extent count for %llu; counted %u, expected %u",
1464 block_group->key.objectid, extent_count,
1465 expected_extent_count);
1466 ASSERT(0);
1467 ret = -EIO;
1468 goto out;
1469 }
1470
1471 caching_ctl->progress = (u64)-1;
1472
1473 ret = 0;
1474 out:
1475 return ret;
1476 }
1477
1478 static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1479 struct btrfs_path *path,
1480 u32 expected_extent_count)
1481 {
1482 struct btrfs_block_group_cache *block_group;
1483 struct btrfs_fs_info *fs_info;
1484 struct btrfs_root *root;
1485 struct btrfs_key key;
1486 u64 end;
1487 u64 total_found = 0;
1488 u32 extent_count = 0;
1489 int ret;
1490
1491 block_group = caching_ctl->block_group;
1492 fs_info = block_group->fs_info;
1493 root = fs_info->free_space_root;
1494
1495 end = block_group->key.objectid + block_group->key.offset;
1496
1497 while (1) {
1498 ret = btrfs_next_item(root, path);
1499 if (ret < 0)
1500 goto out;
1501 if (ret)
1502 break;
1503
1504 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1505
1506 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1507 break;
1508
1509 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1510 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1511
1512 caching_ctl->progress = key.objectid;
1513
1514 total_found += add_new_free_space(block_group, fs_info,
1515 key.objectid,
1516 key.objectid + key.offset);
1517 if (total_found > CACHING_CTL_WAKE_UP) {
1518 total_found = 0;
1519 wake_up(&caching_ctl->wait);
1520 }
1521 extent_count++;
1522 }
1523
1524 if (extent_count != expected_extent_count) {
1525 btrfs_err(fs_info,
1526 "incorrect extent count for %llu; counted %u, expected %u",
1527 block_group->key.objectid, extent_count,
1528 expected_extent_count);
1529 ASSERT(0);
1530 ret = -EIO;
1531 goto out;
1532 }
1533
1534 caching_ctl->progress = (u64)-1;
1535
1536 ret = 0;
1537 out:
1538 return ret;
1539 }
1540
1541 int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
1542 {
1543 struct btrfs_block_group_cache *block_group;
1544 struct btrfs_fs_info *fs_info;
1545 struct btrfs_free_space_info *info;
1546 struct btrfs_path *path;
1547 u32 extent_count, flags;
1548 int ret;
1549
1550 block_group = caching_ctl->block_group;
1551 fs_info = block_group->fs_info;
1552
1553 path = btrfs_alloc_path();
1554 if (!path)
1555 return -ENOMEM;
1556
1557 /*
1558 * Just like caching_thread() doesn't want to deadlock on the extent
1559 * tree, we don't want to deadlock on the free space tree.
1560 */
1561 path->skip_locking = 1;
1562 path->search_commit_root = 1;
1563 path->reada = READA_FORWARD;
1564
1565 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
1566 if (IS_ERR(info)) {
1567 ret = PTR_ERR(info);
1568 goto out;
1569 }
1570 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
1571 flags = btrfs_free_space_flags(path->nodes[0], info);
1572
1573 /*
1574 * We left path pointing to the free space info item, so now
1575 * load_free_space_foo can just iterate through the free space tree from
1576 * there.
1577 */
1578 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS)
1579 ret = load_free_space_bitmaps(caching_ctl, path, extent_count);
1580 else
1581 ret = load_free_space_extents(caching_ctl, path, extent_count);
1582
1583 out:
1584 btrfs_free_path(path);
1585 return ret;
1586 }
Linux with added FPC-III support