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Merge tag 'regmap-fix-v5.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux/fpc-iii.git] / fs / btrfs / free-space-tree.c
blobe33a65bd9a0c281a83bc824dcd5160209583c3f2
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 #include "block-group.h"
14
15 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
16 struct btrfs_block_group *block_group,
17 struct btrfs_path *path);
18
19 void set_free_space_tree_thresholds(struct btrfs_block_group *cache)
20 {
21 u32 bitmap_range;
22 size_t bitmap_size;
23 u64 num_bitmaps, total_bitmap_size;
24
25 if (WARN_ON(cache->length == 0))
26 btrfs_warn(cache->fs_info, "block group %llu length is zero",
27 cache->start);
28
29 /*
30 * We convert to bitmaps when the disk space required for using extents
31 * exceeds that required for using bitmaps.
32 */
33 bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
34 num_bitmaps = div_u64(cache->length + bitmap_range - 1, bitmap_range);
35 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
36 total_bitmap_size = num_bitmaps * bitmap_size;
37 cache->bitmap_high_thresh = div_u64(total_bitmap_size,
38 sizeof(struct btrfs_item));
39
40 /*
41 * We allow for a small buffer between the high threshold and low
42 * threshold to avoid thrashing back and forth between the two formats.
43 */
44 if (cache->bitmap_high_thresh > 100)
45 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
46 else
47 cache->bitmap_low_thresh = 0;
48 }
49
50 static int add_new_free_space_info(struct btrfs_trans_handle *trans,
51 struct btrfs_block_group *block_group,
52 struct btrfs_path *path)
53 {
54 struct btrfs_root *root = trans->fs_info->free_space_root;
55 struct btrfs_free_space_info *info;
56 struct btrfs_key key;
57 struct extent_buffer *leaf;
58 int ret;
59
60 key.objectid = block_group->start;
61 key.type = BTRFS_FREE_SPACE_INFO_KEY;
62 key.offset = block_group->length;
63
64 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
65 if (ret)
66 goto out;
67
68 leaf = path->nodes[0];
69 info = btrfs_item_ptr(leaf, path->slots[0],
70 struct btrfs_free_space_info);
71 btrfs_set_free_space_extent_count(leaf, info, 0);
72 btrfs_set_free_space_flags(leaf, info, 0);
73 btrfs_mark_buffer_dirty(leaf);
74
75 ret = 0;
76 out:
77 btrfs_release_path(path);
78 return ret;
79 }
80
81 EXPORT_FOR_TESTS
82 struct btrfs_free_space_info *search_free_space_info(
83 struct btrfs_trans_handle *trans,
84 struct btrfs_block_group *block_group,
85 struct btrfs_path *path, int cow)
86 {
87 struct btrfs_fs_info *fs_info = block_group->fs_info;
88 struct btrfs_root *root = fs_info->free_space_root;
89 struct btrfs_key key;
90 int ret;
91
92 key.objectid = block_group->start;
93 key.type = BTRFS_FREE_SPACE_INFO_KEY;
94 key.offset = block_group->length;
95
96 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
97 if (ret < 0)
98 return ERR_PTR(ret);
99 if (ret != 0) {
100 btrfs_warn(fs_info, "missing free space info for %llu",
101 block_group->start);
102 ASSERT(0);
103 return ERR_PTR(-ENOENT);
104 }
105
106 return btrfs_item_ptr(path->nodes[0], path->slots[0],
107 struct btrfs_free_space_info);
108 }
109
110 /*
111 * btrfs_search_slot() but we're looking for the greatest key less than the
112 * passed key.
113 */
114 static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
115 struct btrfs_root *root,
116 struct btrfs_key *key, struct btrfs_path *p,
117 int ins_len, int cow)
118 {
119 int ret;
120
121 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
122 if (ret < 0)
123 return ret;
124
125 if (ret == 0) {
126 ASSERT(0);
127 return -EIO;
128 }
129
130 if (p->slots[0] == 0) {
131 ASSERT(0);
132 return -EIO;
133 }
134 p->slots[0]--;
135
136 return 0;
137 }
138
139 static inline u32 free_space_bitmap_size(const struct btrfs_fs_info *fs_info,
140 u64 size)
141 {
142 return DIV_ROUND_UP(size >> fs_info->sectorsize_bits, BITS_PER_BYTE);
143 }
144
145 static unsigned long *alloc_bitmap(u32 bitmap_size)
146 {
147 unsigned long *ret;
148 unsigned int nofs_flag;
149 u32 bitmap_rounded_size = round_up(bitmap_size, sizeof(unsigned long));
150
151 /*
152 * GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse
153 * into the filesystem as the free space bitmap can be modified in the
154 * critical section of a transaction commit.
155 *
156 * TODO: push the memalloc_nofs_{save,restore}() to the caller where we
157 * know that recursion is unsafe.
158 */
159 nofs_flag = memalloc_nofs_save();
160 ret = kvzalloc(bitmap_rounded_size, GFP_KERNEL);
161 memalloc_nofs_restore(nofs_flag);
162 return ret;
163 }
164
165 static void le_bitmap_set(unsigned long *map, unsigned int start, int len)
166 {
167 u8 *p = ((u8 *)map) + BIT_BYTE(start);
168 const unsigned int size = start + len;
169 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
170 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
171
172 while (len - bits_to_set >= 0) {
173 *p |= mask_to_set;
174 len -= bits_to_set;
175 bits_to_set = BITS_PER_BYTE;
176 mask_to_set = ~0;
177 p++;
178 }
179 if (len) {
180 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
181 *p |= mask_to_set;
182 }
183 }
184
185 EXPORT_FOR_TESTS
186 int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
187 struct btrfs_block_group *block_group,
188 struct btrfs_path *path)
189 {
190 struct btrfs_fs_info *fs_info = trans->fs_info;
191 struct btrfs_root *root = fs_info->free_space_root;
192 struct btrfs_free_space_info *info;
193 struct btrfs_key key, found_key;
194 struct extent_buffer *leaf;
195 unsigned long *bitmap;
196 char *bitmap_cursor;
197 u64 start, end;
198 u64 bitmap_range, i;
199 u32 bitmap_size, flags, expected_extent_count;
200 u32 extent_count = 0;
201 int done = 0, nr;
202 int ret;
203
204 bitmap_size = free_space_bitmap_size(fs_info, block_group->length);
205 bitmap = alloc_bitmap(bitmap_size);
206 if (!bitmap) {
207 ret = -ENOMEM;
208 goto out;
209 }
210
211 start = block_group->start;
212 end = block_group->start + block_group->length;
213
214 key.objectid = end - 1;
215 key.type = (u8)-1;
216 key.offset = (u64)-1;
217
218 while (!done) {
219 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
220 if (ret)
221 goto out;
222
223 leaf = path->nodes[0];
224 nr = 0;
225 path->slots[0]++;
226 while (path->slots[0] > 0) {
227 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
228
229 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
230 ASSERT(found_key.objectid == block_group->start);
231 ASSERT(found_key.offset == block_group->length);
232 done = 1;
233 break;
234 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
235 u64 first, last;
236
237 ASSERT(found_key.objectid >= start);
238 ASSERT(found_key.objectid < end);
239 ASSERT(found_key.objectid + found_key.offset <= end);
240
241 first = div_u64(found_key.objectid - start,
242 fs_info->sectorsize);
243 last = div_u64(found_key.objectid + found_key.offset - start,
244 fs_info->sectorsize);
245 le_bitmap_set(bitmap, first, last - first);
246
247 extent_count++;
248 nr++;
249 path->slots[0]--;
250 } else {
251 ASSERT(0);
252 }
253 }
254
255 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
256 if (ret)
257 goto out;
258 btrfs_release_path(path);
259 }
260
261 info = search_free_space_info(trans, block_group, path, 1);
262 if (IS_ERR(info)) {
263 ret = PTR_ERR(info);
264 goto out;
265 }
266 leaf = path->nodes[0];
267 flags = btrfs_free_space_flags(leaf, info);
268 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
269 btrfs_set_free_space_flags(leaf, info, flags);
270 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
271 btrfs_mark_buffer_dirty(leaf);
272 btrfs_release_path(path);
273
274 if (extent_count != expected_extent_count) {
275 btrfs_err(fs_info,
276 "incorrect extent count for %llu; counted %u, expected %u",
277 block_group->start, extent_count,
278 expected_extent_count);
279 ASSERT(0);
280 ret = -EIO;
281 goto out;
282 }
283
284 bitmap_cursor = (char *)bitmap;
285 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
286 i = start;
287 while (i < end) {
288 unsigned long ptr;
289 u64 extent_size;
290 u32 data_size;
291
292 extent_size = min(end - i, bitmap_range);
293 data_size = free_space_bitmap_size(fs_info, extent_size);
294
295 key.objectid = i;
296 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
297 key.offset = extent_size;
298
299 ret = btrfs_insert_empty_item(trans, root, path, &key,
300 data_size);
301 if (ret)
302 goto out;
303
304 leaf = path->nodes[0];
305 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
306 write_extent_buffer(leaf, bitmap_cursor, ptr,
307 data_size);
308 btrfs_mark_buffer_dirty(leaf);
309 btrfs_release_path(path);
310
311 i += extent_size;
312 bitmap_cursor += data_size;
313 }
314
315 ret = 0;
316 out:
317 kvfree(bitmap);
318 if (ret)
319 btrfs_abort_transaction(trans, ret);
320 return ret;
321 }
322
323 EXPORT_FOR_TESTS
324 int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
325 struct btrfs_block_group *block_group,
326 struct btrfs_path *path)
327 {
328 struct btrfs_fs_info *fs_info = trans->fs_info;
329 struct btrfs_root *root = fs_info->free_space_root;
330 struct btrfs_free_space_info *info;
331 struct btrfs_key key, found_key;
332 struct extent_buffer *leaf;
333 unsigned long *bitmap;
334 u64 start, end;
335 u32 bitmap_size, flags, expected_extent_count;
336 unsigned long nrbits, start_bit, end_bit;
337 u32 extent_count = 0;
338 int done = 0, nr;
339 int ret;
340
341 bitmap_size = free_space_bitmap_size(fs_info, block_group->length);
342 bitmap = alloc_bitmap(bitmap_size);
343 if (!bitmap) {
344 ret = -ENOMEM;
345 goto out;
346 }
347
348 start = block_group->start;
349 end = block_group->start + block_group->length;
350
351 key.objectid = end - 1;
352 key.type = (u8)-1;
353 key.offset = (u64)-1;
354
355 while (!done) {
356 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
357 if (ret)
358 goto out;
359
360 leaf = path->nodes[0];
361 nr = 0;
362 path->slots[0]++;
363 while (path->slots[0] > 0) {
364 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
365
366 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
367 ASSERT(found_key.objectid == block_group->start);
368 ASSERT(found_key.offset == block_group->length);
369 done = 1;
370 break;
371 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
372 unsigned long ptr;
373 char *bitmap_cursor;
374 u32 bitmap_pos, data_size;
375
376 ASSERT(found_key.objectid >= start);
377 ASSERT(found_key.objectid < end);
378 ASSERT(found_key.objectid + found_key.offset <= end);
379
380 bitmap_pos = div_u64(found_key.objectid - start,
381 fs_info->sectorsize *
382 BITS_PER_BYTE);
383 bitmap_cursor = ((char *)bitmap) + bitmap_pos;
384 data_size = free_space_bitmap_size(fs_info,
385 found_key.offset);
386
387 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
388 read_extent_buffer(leaf, bitmap_cursor, ptr,
389 data_size);
390
391 nr++;
392 path->slots[0]--;
393 } else {
394 ASSERT(0);
395 }
396 }
397
398 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
399 if (ret)
400 goto out;
401 btrfs_release_path(path);
402 }
403
404 info = search_free_space_info(trans, block_group, path, 1);
405 if (IS_ERR(info)) {
406 ret = PTR_ERR(info);
407 goto out;
408 }
409 leaf = path->nodes[0];
410 flags = btrfs_free_space_flags(leaf, info);
411 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
412 btrfs_set_free_space_flags(leaf, info, flags);
413 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
414 btrfs_mark_buffer_dirty(leaf);
415 btrfs_release_path(path);
416
417 nrbits = block_group->length >> block_group->fs_info->sectorsize_bits;
418 start_bit = find_next_bit_le(bitmap, nrbits, 0);
419
420 while (start_bit < nrbits) {
421 end_bit = find_next_zero_bit_le(bitmap, nrbits, start_bit);
422 ASSERT(start_bit < end_bit);
423
424 key.objectid = start + start_bit * block_group->fs_info->sectorsize;
425 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
426 key.offset = (end_bit - start_bit) * block_group->fs_info->sectorsize;
427
428 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
429 if (ret)
430 goto out;
431 btrfs_release_path(path);
432
433 extent_count++;
434
435 start_bit = find_next_bit_le(bitmap, nrbits, end_bit);
436 }
437
438 if (extent_count != expected_extent_count) {
439 btrfs_err(fs_info,
440 "incorrect extent count for %llu; counted %u, expected %u",
441 block_group->start, extent_count,
442 expected_extent_count);
443 ASSERT(0);
444 ret = -EIO;
445 goto out;
446 }
447
448 ret = 0;
449 out:
450 kvfree(bitmap);
451 if (ret)
452 btrfs_abort_transaction(trans, ret);
453 return ret;
454 }
455
456 static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
457 struct btrfs_block_group *block_group,
458 struct btrfs_path *path,
459 int new_extents)
460 {
461 struct btrfs_free_space_info *info;
462 u32 flags;
463 u32 extent_count;
464 int ret = 0;
465
466 if (new_extents == 0)
467 return 0;
468
469 info = search_free_space_info(trans, block_group, path, 1);
470 if (IS_ERR(info)) {
471 ret = PTR_ERR(info);
472 goto out;
473 }
474 flags = btrfs_free_space_flags(path->nodes[0], info);
475 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
476
477 extent_count += new_extents;
478 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
479 btrfs_mark_buffer_dirty(path->nodes[0]);
480 btrfs_release_path(path);
481
482 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
483 extent_count > block_group->bitmap_high_thresh) {
484 ret = convert_free_space_to_bitmaps(trans, block_group, path);
485 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
486 extent_count < block_group->bitmap_low_thresh) {
487 ret = convert_free_space_to_extents(trans, block_group, path);
488 }
489
490 out:
491 return ret;
492 }
493
494 EXPORT_FOR_TESTS
495 int free_space_test_bit(struct btrfs_block_group *block_group,
496 struct btrfs_path *path, u64 offset)
497 {
498 struct extent_buffer *leaf;
499 struct btrfs_key key;
500 u64 found_start, found_end;
501 unsigned long ptr, i;
502
503 leaf = path->nodes[0];
504 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
505 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
506
507 found_start = key.objectid;
508 found_end = key.objectid + key.offset;
509 ASSERT(offset >= found_start && offset < found_end);
510
511 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
512 i = div_u64(offset - found_start,
513 block_group->fs_info->sectorsize);
514 return !!extent_buffer_test_bit(leaf, ptr, i);
515 }
516
517 static void free_space_set_bits(struct btrfs_block_group *block_group,
518 struct btrfs_path *path, u64 *start, u64 *size,
519 int bit)
520 {
521 struct btrfs_fs_info *fs_info = block_group->fs_info;
522 struct extent_buffer *leaf;
523 struct btrfs_key key;
524 u64 end = *start + *size;
525 u64 found_start, found_end;
526 unsigned long ptr, first, last;
527
528 leaf = path->nodes[0];
529 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
530 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
531
532 found_start = key.objectid;
533 found_end = key.objectid + key.offset;
534 ASSERT(*start >= found_start && *start < found_end);
535 ASSERT(end > found_start);
536
537 if (end > found_end)
538 end = found_end;
539
540 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
541 first = (*start - found_start) >> fs_info->sectorsize_bits;
542 last = (end - found_start) >> fs_info->sectorsize_bits;
543 if (bit)
544 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
545 else
546 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
547 btrfs_mark_buffer_dirty(leaf);
548
549 *size -= end - *start;
550 *start = end;
551 }
552
553 /*
554 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
555 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
556 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
557 * looking for.
558 */
559 static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
560 struct btrfs_root *root, struct btrfs_path *p)
561 {
562 struct btrfs_key key;
563
564 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
565 p->slots[0]++;
566 return 0;
567 }
568
569 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
570 btrfs_release_path(p);
571
572 key.objectid += key.offset;
573 key.type = (u8)-1;
574 key.offset = (u64)-1;
575
576 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
577 }
578
579 /*
580 * If remove is 1, then we are removing free space, thus clearing bits in the
581 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
582 * the bitmap.
583 */
584 static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
585 struct btrfs_block_group *block_group,
586 struct btrfs_path *path,
587 u64 start, u64 size, int remove)
588 {
589 struct btrfs_root *root = block_group->fs_info->free_space_root;
590 struct btrfs_key key;
591 u64 end = start + size;
592 u64 cur_start, cur_size;
593 int prev_bit, next_bit;
594 int new_extents;
595 int ret;
596
597 /*
598 * Read the bit for the block immediately before the extent of space if
599 * that block is within the block group.
600 */
601 if (start > block_group->start) {
602 u64 prev_block = start - block_group->fs_info->sectorsize;
603
604 key.objectid = prev_block;
605 key.type = (u8)-1;
606 key.offset = (u64)-1;
607
608 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
609 if (ret)
610 goto out;
611
612 prev_bit = free_space_test_bit(block_group, path, prev_block);
613
614 /* The previous block may have been in the previous bitmap. */
615 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
616 if (start >= key.objectid + key.offset) {
617 ret = free_space_next_bitmap(trans, root, path);
618 if (ret)
619 goto out;
620 }
621 } else {
622 key.objectid = start;
623 key.type = (u8)-1;
624 key.offset = (u64)-1;
625
626 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
627 if (ret)
628 goto out;
629
630 prev_bit = -1;
631 }
632
633 /*
634 * Iterate over all of the bitmaps overlapped by the extent of space,
635 * clearing/setting bits as required.
636 */
637 cur_start = start;
638 cur_size = size;
639 while (1) {
640 free_space_set_bits(block_group, path, &cur_start, &cur_size,
641 !remove);
642 if (cur_size == 0)
643 break;
644 ret = free_space_next_bitmap(trans, root, path);
645 if (ret)
646 goto out;
647 }
648
649 /*
650 * Read the bit for the block immediately after the extent of space if
651 * that block is within the block group.
652 */
653 if (end < block_group->start + block_group->length) {
654 /* The next block may be in the next bitmap. */
655 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
656 if (end >= key.objectid + key.offset) {
657 ret = free_space_next_bitmap(trans, root, path);
658 if (ret)
659 goto out;
660 }
661
662 next_bit = free_space_test_bit(block_group, path, end);
663 } else {
664 next_bit = -1;
665 }
666
667 if (remove) {
668 new_extents = -1;
669 if (prev_bit == 1) {
670 /* Leftover on the left. */
671 new_extents++;
672 }
673 if (next_bit == 1) {
674 /* Leftover on the right. */
675 new_extents++;
676 }
677 } else {
678 new_extents = 1;
679 if (prev_bit == 1) {
680 /* Merging with neighbor on the left. */
681 new_extents--;
682 }
683 if (next_bit == 1) {
684 /* Merging with neighbor on the right. */
685 new_extents--;
686 }
687 }
688
689 btrfs_release_path(path);
690 ret = update_free_space_extent_count(trans, block_group, path,
691 new_extents);
692
693 out:
694 return ret;
695 }
696
697 static int remove_free_space_extent(struct btrfs_trans_handle *trans,
698 struct btrfs_block_group *block_group,
699 struct btrfs_path *path,
700 u64 start, u64 size)
701 {
702 struct btrfs_root *root = trans->fs_info->free_space_root;
703 struct btrfs_key key;
704 u64 found_start, found_end;
705 u64 end = start + size;
706 int new_extents = -1;
707 int ret;
708
709 key.objectid = start;
710 key.type = (u8)-1;
711 key.offset = (u64)-1;
712
713 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
714 if (ret)
715 goto out;
716
717 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
718
719 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
720
721 found_start = key.objectid;
722 found_end = key.objectid + key.offset;
723 ASSERT(start >= found_start && end <= found_end);
724
725 /*
726 * Okay, now that we've found the free space extent which contains the
727 * free space that we are removing, there are four cases:
728 *
729 * 1. We're using the whole extent: delete the key we found and
730 * decrement the free space extent count.
731 * 2. We are using part of the extent starting at the beginning: delete
732 * the key we found and insert a new key representing the leftover at
733 * the end. There is no net change in the number of extents.
734 * 3. We are using part of the extent ending at the end: delete the key
735 * we found and insert a new key representing the leftover at the
736 * beginning. There is no net change in the number of extents.
737 * 4. We are using part of the extent in the middle: delete the key we
738 * found and insert two new keys representing the leftovers on each
739 * side. Where we used to have one extent, we now have two, so increment
740 * the extent count. We may need to convert the block group to bitmaps
741 * as a result.
742 */
743
744 /* Delete the existing key (cases 1-4). */
745 ret = btrfs_del_item(trans, root, path);
746 if (ret)
747 goto out;
748
749 /* Add a key for leftovers at the beginning (cases 3 and 4). */
750 if (start > found_start) {
751 key.objectid = found_start;
752 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
753 key.offset = start - found_start;
754
755 btrfs_release_path(path);
756 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
757 if (ret)
758 goto out;
759 new_extents++;
760 }
761
762 /* Add a key for leftovers at the end (cases 2 and 4). */
763 if (end < found_end) {
764 key.objectid = end;
765 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
766 key.offset = found_end - end;
767
768 btrfs_release_path(path);
769 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
770 if (ret)
771 goto out;
772 new_extents++;
773 }
774
775 btrfs_release_path(path);
776 ret = update_free_space_extent_count(trans, block_group, path,
777 new_extents);
778
779 out:
780 return ret;
781 }
782
783 EXPORT_FOR_TESTS
784 int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
785 struct btrfs_block_group *block_group,
786 struct btrfs_path *path, u64 start, u64 size)
787 {
788 struct btrfs_free_space_info *info;
789 u32 flags;
790 int ret;
791
792 if (block_group->needs_free_space) {
793 ret = __add_block_group_free_space(trans, block_group, path);
794 if (ret)
795 return ret;
796 }
797
798 info = search_free_space_info(NULL, block_group, path, 0);
799 if (IS_ERR(info))
800 return PTR_ERR(info);
801 flags = btrfs_free_space_flags(path->nodes[0], info);
802 btrfs_release_path(path);
803
804 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
805 return modify_free_space_bitmap(trans, block_group, path,
806 start, size, 1);
807 } else {
808 return remove_free_space_extent(trans, block_group, path,
809 start, size);
810 }
811 }
812
813 int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
814 u64 start, u64 size)
815 {
816 struct btrfs_block_group *block_group;
817 struct btrfs_path *path;
818 int ret;
819
820 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
821 return 0;
822
823 path = btrfs_alloc_path();
824 if (!path) {
825 ret = -ENOMEM;
826 goto out;
827 }
828
829 block_group = btrfs_lookup_block_group(trans->fs_info, start);
830 if (!block_group) {
831 ASSERT(0);
832 ret = -ENOENT;
833 goto out;
834 }
835
836 mutex_lock(&block_group->free_space_lock);
837 ret = __remove_from_free_space_tree(trans, block_group, path, start,
838 size);
839 mutex_unlock(&block_group->free_space_lock);
840
841 btrfs_put_block_group(block_group);
842 out:
843 btrfs_free_path(path);
844 if (ret)
845 btrfs_abort_transaction(trans, ret);
846 return ret;
847 }
848
849 static int add_free_space_extent(struct btrfs_trans_handle *trans,
850 struct btrfs_block_group *block_group,
851 struct btrfs_path *path,
852 u64 start, u64 size)
853 {
854 struct btrfs_root *root = trans->fs_info->free_space_root;
855 struct btrfs_key key, new_key;
856 u64 found_start, found_end;
857 u64 end = start + size;
858 int new_extents = 1;
859 int ret;
860
861 /*
862 * We are adding a new extent of free space, but we need to merge
863 * extents. There are four cases here:
864 *
865 * 1. The new extent does not have any immediate neighbors to merge
866 * with: add the new key and increment the free space extent count. We
867 * may need to convert the block group to bitmaps as a result.
868 * 2. The new extent has an immediate neighbor before it: remove the
869 * previous key and insert a new key combining both of them. There is no
870 * net change in the number of extents.
871 * 3. The new extent has an immediate neighbor after it: remove the next
872 * key and insert a new key combining both of them. There is no net
873 * change in the number of extents.
874 * 4. The new extent has immediate neighbors on both sides: remove both
875 * of the keys and insert a new key combining all of them. Where we used
876 * to have two extents, we now have one, so decrement the extent count.
877 */
878
879 new_key.objectid = start;
880 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
881 new_key.offset = size;
882
883 /* Search for a neighbor on the left. */
884 if (start == block_group->start)
885 goto right;
886 key.objectid = start - 1;
887 key.type = (u8)-1;
888 key.offset = (u64)-1;
889
890 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
891 if (ret)
892 goto out;
893
894 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
895
896 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
897 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
898 btrfs_release_path(path);
899 goto right;
900 }
901
902 found_start = key.objectid;
903 found_end = key.objectid + key.offset;
904 ASSERT(found_start >= block_group->start &&
905 found_end > block_group->start);
906 ASSERT(found_start < start && found_end <= start);
907
908 /*
909 * Delete the neighbor on the left and absorb it into the new key (cases
910 * 2 and 4).
911 */
912 if (found_end == start) {
913 ret = btrfs_del_item(trans, root, path);
914 if (ret)
915 goto out;
916 new_key.objectid = found_start;
917 new_key.offset += key.offset;
918 new_extents--;
919 }
920 btrfs_release_path(path);
921
922 right:
923 /* Search for a neighbor on the right. */
924 if (end == block_group->start + block_group->length)
925 goto insert;
926 key.objectid = end;
927 key.type = (u8)-1;
928 key.offset = (u64)-1;
929
930 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
931 if (ret)
932 goto out;
933
934 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
935
936 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
937 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
938 btrfs_release_path(path);
939 goto insert;
940 }
941
942 found_start = key.objectid;
943 found_end = key.objectid + key.offset;
944 ASSERT(found_start >= block_group->start &&
945 found_end > block_group->start);
946 ASSERT((found_start < start && found_end <= start) ||
947 (found_start >= end && found_end > end));
948
949 /*
950 * Delete the neighbor on the right and absorb it into the new key
951 * (cases 3 and 4).
952 */
953 if (found_start == end) {
954 ret = btrfs_del_item(trans, root, path);
955 if (ret)
956 goto out;
957 new_key.offset += key.offset;
958 new_extents--;
959 }
960 btrfs_release_path(path);
961
962 insert:
963 /* Insert the new key (cases 1-4). */
964 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
965 if (ret)
966 goto out;
967
968 btrfs_release_path(path);
969 ret = update_free_space_extent_count(trans, block_group, path,
970 new_extents);
971
972 out:
973 return ret;
974 }
975
976 EXPORT_FOR_TESTS
977 int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
978 struct btrfs_block_group *block_group,
979 struct btrfs_path *path, u64 start, u64 size)
980 {
981 struct btrfs_free_space_info *info;
982 u32 flags;
983 int ret;
984
985 if (block_group->needs_free_space) {
986 ret = __add_block_group_free_space(trans, block_group, path);
987 if (ret)
988 return ret;
989 }
990
991 info = search_free_space_info(NULL, 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, block_group, path,
999 start, size, 0);
1000 } else {
1001 return add_free_space_extent(trans, block_group, path, start,
1002 size);
1003 }
1004 }
1005
1006 int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1007 u64 start, u64 size)
1008 {
1009 struct btrfs_block_group *block_group;
1010 struct btrfs_path *path;
1011 int ret;
1012
1013 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1014 return 0;
1015
1016 path = btrfs_alloc_path();
1017 if (!path) {
1018 ret = -ENOMEM;
1019 goto out;
1020 }
1021
1022 block_group = btrfs_lookup_block_group(trans->fs_info, start);
1023 if (!block_group) {
1024 ASSERT(0);
1025 ret = -ENOENT;
1026 goto out;
1027 }
1028
1029 mutex_lock(&block_group->free_space_lock);
1030 ret = __add_to_free_space_tree(trans, block_group, path, start, size);
1031 mutex_unlock(&block_group->free_space_lock);
1032
1033 btrfs_put_block_group(block_group);
1034 out:
1035 btrfs_free_path(path);
1036 if (ret)
1037 btrfs_abort_transaction(trans, ret);
1038 return ret;
1039 }
1040
1041 /*
1042 * Populate the free space tree by walking the extent tree. Operations on the
1043 * extent tree that happen as a result of writes to the free space tree will go
1044 * through the normal add/remove hooks.
1045 */
1046 static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1047 struct btrfs_block_group *block_group)
1048 {
1049 struct btrfs_root *extent_root = trans->fs_info->extent_root;
1050 struct btrfs_path *path, *path2;
1051 struct btrfs_key key;
1052 u64 start, end;
1053 int ret;
1054
1055 path = btrfs_alloc_path();
1056 if (!path)
1057 return -ENOMEM;
1058 path->reada = READA_FORWARD;
1059
1060 path2 = btrfs_alloc_path();
1061 if (!path2) {
1062 btrfs_free_path(path);
1063 return -ENOMEM;
1064 }
1065
1066 ret = add_new_free_space_info(trans, block_group, path2);
1067 if (ret)
1068 goto out;
1069
1070 mutex_lock(&block_group->free_space_lock);
1071
1072 /*
1073 * Iterate through all of the extent and metadata items in this block
1074 * group, adding the free space between them and the free space at the
1075 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1076 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1077 * contained in.
1078 */
1079 key.objectid = block_group->start;
1080 key.type = BTRFS_EXTENT_ITEM_KEY;
1081 key.offset = 0;
1082
1083 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1084 if (ret < 0)
1085 goto out_locked;
1086 ASSERT(ret == 0);
1087
1088 start = block_group->start;
1089 end = block_group->start + block_group->length;
1090 while (1) {
1091 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1092
1093 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1094 key.type == BTRFS_METADATA_ITEM_KEY) {
1095 if (key.objectid >= end)
1096 break;
1097
1098 if (start < key.objectid) {
1099 ret = __add_to_free_space_tree(trans,
1100 block_group,
1101 path2, start,
1102 key.objectid -
1103 start);
1104 if (ret)
1105 goto out_locked;
1106 }
1107 start = key.objectid;
1108 if (key.type == BTRFS_METADATA_ITEM_KEY)
1109 start += trans->fs_info->nodesize;
1110 else
1111 start += key.offset;
1112 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1113 if (key.objectid != block_group->start)
1114 break;
1115 }
1116
1117 ret = btrfs_next_item(extent_root, path);
1118 if (ret < 0)
1119 goto out_locked;
1120 if (ret)
1121 break;
1122 }
1123 if (start < end) {
1124 ret = __add_to_free_space_tree(trans, block_group, path2,
1125 start, end - start);
1126 if (ret)
1127 goto out_locked;
1128 }
1129
1130 ret = 0;
1131 out_locked:
1132 mutex_unlock(&block_group->free_space_lock);
1133 out:
1134 btrfs_free_path(path2);
1135 btrfs_free_path(path);
1136 return ret;
1137 }
1138
1139 int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1140 {
1141 struct btrfs_trans_handle *trans;
1142 struct btrfs_root *tree_root = fs_info->tree_root;
1143 struct btrfs_root *free_space_root;
1144 struct btrfs_block_group *block_group;
1145 struct rb_node *node;
1146 int ret;
1147
1148 trans = btrfs_start_transaction(tree_root, 0);
1149 if (IS_ERR(trans))
1150 return PTR_ERR(trans);
1151
1152 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1153 free_space_root = btrfs_create_tree(trans,
1154 BTRFS_FREE_SPACE_TREE_OBJECTID);
1155 if (IS_ERR(free_space_root)) {
1156 ret = PTR_ERR(free_space_root);
1157 goto abort;
1158 }
1159 fs_info->free_space_root = free_space_root;
1160
1161 node = rb_first(&fs_info->block_group_cache_tree);
1162 while (node) {
1163 block_group = rb_entry(node, struct btrfs_block_group,
1164 cache_node);
1165 ret = populate_free_space_tree(trans, block_group);
1166 if (ret)
1167 goto abort;
1168 node = rb_next(node);
1169 }
1170
1171 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1172 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1173 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1174
1175 return btrfs_commit_transaction(trans);
1176
1177 abort:
1178 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1179 btrfs_abort_transaction(trans, ret);
1180 btrfs_end_transaction(trans);
1181 return ret;
1182 }
1183
1184 static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1185 struct btrfs_root *root)
1186 {
1187 struct btrfs_path *path;
1188 struct btrfs_key key;
1189 int nr;
1190 int ret;
1191
1192 path = btrfs_alloc_path();
1193 if (!path)
1194 return -ENOMEM;
1195
1196 key.objectid = 0;
1197 key.type = 0;
1198 key.offset = 0;
1199
1200 while (1) {
1201 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1202 if (ret < 0)
1203 goto out;
1204
1205 nr = btrfs_header_nritems(path->nodes[0]);
1206 if (!nr)
1207 break;
1208
1209 path->slots[0] = 0;
1210 ret = btrfs_del_items(trans, root, path, 0, nr);
1211 if (ret)
1212 goto out;
1213
1214 btrfs_release_path(path);
1215 }
1216
1217 ret = 0;
1218 out:
1219 btrfs_free_path(path);
1220 return ret;
1221 }
1222
1223 int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
1224 {
1225 struct btrfs_trans_handle *trans;
1226 struct btrfs_root *tree_root = fs_info->tree_root;
1227 struct btrfs_root *free_space_root = fs_info->free_space_root;
1228 int ret;
1229
1230 trans = btrfs_start_transaction(tree_root, 0);
1231 if (IS_ERR(trans))
1232 return PTR_ERR(trans);
1233
1234 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1235 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1236 fs_info->free_space_root = NULL;
1237
1238 ret = clear_free_space_tree(trans, free_space_root);
1239 if (ret)
1240 goto abort;
1241
1242 ret = btrfs_del_root(trans, &free_space_root->root_key);
1243 if (ret)
1244 goto abort;
1245
1246 list_del(&free_space_root->dirty_list);
1247
1248 btrfs_tree_lock(free_space_root->node);
1249 btrfs_clean_tree_block(free_space_root->node);
1250 btrfs_tree_unlock(free_space_root->node);
1251 btrfs_free_tree_block(trans, free_space_root, free_space_root->node,
1252 0, 1);
1253
1254 btrfs_put_root(free_space_root);
1255
1256 return btrfs_commit_transaction(trans);
1257
1258 abort:
1259 btrfs_abort_transaction(trans, ret);
1260 btrfs_end_transaction(trans);
1261 return ret;
1262 }
1263
1264 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
1265 struct btrfs_block_group *block_group,
1266 struct btrfs_path *path)
1267 {
1268 int ret;
1269
1270 block_group->needs_free_space = 0;
1271
1272 ret = add_new_free_space_info(trans, block_group, path);
1273 if (ret)
1274 return ret;
1275
1276 return __add_to_free_space_tree(trans, block_group, path,
1277 block_group->start,
1278 block_group->length);
1279 }
1280
1281 int add_block_group_free_space(struct btrfs_trans_handle *trans,
1282 struct btrfs_block_group *block_group)
1283 {
1284 struct btrfs_fs_info *fs_info = trans->fs_info;
1285 struct btrfs_path *path = NULL;
1286 int ret = 0;
1287
1288 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1289 return 0;
1290
1291 mutex_lock(&block_group->free_space_lock);
1292 if (!block_group->needs_free_space)
1293 goto out;
1294
1295 path = btrfs_alloc_path();
1296 if (!path) {
1297 ret = -ENOMEM;
1298 goto out;
1299 }
1300
1301 ret = __add_block_group_free_space(trans, block_group, path);
1302
1303 out:
1304 btrfs_free_path(path);
1305 mutex_unlock(&block_group->free_space_lock);
1306 if (ret)
1307 btrfs_abort_transaction(trans, ret);
1308 return ret;
1309 }
1310
1311 int remove_block_group_free_space(struct btrfs_trans_handle *trans,
1312 struct btrfs_block_group *block_group)
1313 {
1314 struct btrfs_root *root = trans->fs_info->free_space_root;
1315 struct btrfs_path *path;
1316 struct btrfs_key key, found_key;
1317 struct extent_buffer *leaf;
1318 u64 start, end;
1319 int done = 0, nr;
1320 int ret;
1321
1322 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1323 return 0;
1324
1325 if (block_group->needs_free_space) {
1326 /* We never added this block group to the free space tree. */
1327 return 0;
1328 }
1329
1330 path = btrfs_alloc_path();
1331 if (!path) {
1332 ret = -ENOMEM;
1333 goto out;
1334 }
1335
1336 start = block_group->start;
1337 end = block_group->start + block_group->length;
1338
1339 key.objectid = end - 1;
1340 key.type = (u8)-1;
1341 key.offset = (u64)-1;
1342
1343 while (!done) {
1344 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1345 if (ret)
1346 goto out;
1347
1348 leaf = path->nodes[0];
1349 nr = 0;
1350 path->slots[0]++;
1351 while (path->slots[0] > 0) {
1352 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1353
1354 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
1355 ASSERT(found_key.objectid == block_group->start);
1356 ASSERT(found_key.offset == block_group->length);
1357 done = 1;
1358 nr++;
1359 path->slots[0]--;
1360 break;
1361 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY ||
1362 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
1363 ASSERT(found_key.objectid >= start);
1364 ASSERT(found_key.objectid < end);
1365 ASSERT(found_key.objectid + found_key.offset <= end);
1366 nr++;
1367 path->slots[0]--;
1368 } else {
1369 ASSERT(0);
1370 }
1371 }
1372
1373 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1374 if (ret)
1375 goto out;
1376 btrfs_release_path(path);
1377 }
1378
1379 ret = 0;
1380 out:
1381 btrfs_free_path(path);
1382 if (ret)
1383 btrfs_abort_transaction(trans, ret);
1384 return ret;
1385 }
1386
1387 static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1388 struct btrfs_path *path,
1389 u32 expected_extent_count)
1390 {
1391 struct btrfs_block_group *block_group;
1392 struct btrfs_fs_info *fs_info;
1393 struct btrfs_root *root;
1394 struct btrfs_key key;
1395 int prev_bit = 0, bit;
1396 /* Initialize to silence GCC. */
1397 u64 extent_start = 0;
1398 u64 end, offset;
1399 u64 total_found = 0;
1400 u32 extent_count = 0;
1401 int ret;
1402
1403 block_group = caching_ctl->block_group;
1404 fs_info = block_group->fs_info;
1405 root = fs_info->free_space_root;
1406
1407 end = block_group->start + block_group->length;
1408
1409 while (1) {
1410 ret = btrfs_next_item(root, path);
1411 if (ret < 0)
1412 goto out;
1413 if (ret)
1414 break;
1415
1416 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1417
1418 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1419 break;
1420
1421 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1422 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1423
1424 caching_ctl->progress = key.objectid;
1425
1426 offset = key.objectid;
1427 while (offset < key.objectid + key.offset) {
1428 bit = free_space_test_bit(block_group, path, offset);
1429 if (prev_bit == 0 && bit == 1) {
1430 extent_start = offset;
1431 } else if (prev_bit == 1 && bit == 0) {
1432 total_found += add_new_free_space(block_group,
1433 extent_start,
1434 offset);
1435 if (total_found > CACHING_CTL_WAKE_UP) {
1436 total_found = 0;
1437 wake_up(&caching_ctl->wait);
1438 }
1439 extent_count++;
1440 }
1441 prev_bit = bit;
1442 offset += fs_info->sectorsize;
1443 }
1444 }
1445 if (prev_bit == 1) {
1446 total_found += add_new_free_space(block_group, extent_start,
1447 end);
1448 extent_count++;
1449 }
1450
1451 if (extent_count != expected_extent_count) {
1452 btrfs_err(fs_info,
1453 "incorrect extent count for %llu; counted %u, expected %u",
1454 block_group->start, extent_count,
1455 expected_extent_count);
1456 ASSERT(0);
1457 ret = -EIO;
1458 goto out;
1459 }
1460
1461 caching_ctl->progress = (u64)-1;
1462
1463 ret = 0;
1464 out:
1465 return ret;
1466 }
1467
1468 static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1469 struct btrfs_path *path,
1470 u32 expected_extent_count)
1471 {
1472 struct btrfs_block_group *block_group;
1473 struct btrfs_fs_info *fs_info;
1474 struct btrfs_root *root;
1475 struct btrfs_key key;
1476 u64 end;
1477 u64 total_found = 0;
1478 u32 extent_count = 0;
1479 int ret;
1480
1481 block_group = caching_ctl->block_group;
1482 fs_info = block_group->fs_info;
1483 root = fs_info->free_space_root;
1484
1485 end = block_group->start + block_group->length;
1486
1487 while (1) {
1488 ret = btrfs_next_item(root, path);
1489 if (ret < 0)
1490 goto out;
1491 if (ret)
1492 break;
1493
1494 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1495
1496 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1497 break;
1498
1499 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1500 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1501
1502 caching_ctl->progress = key.objectid;
1503
1504 total_found += add_new_free_space(block_group, key.objectid,
1505 key.objectid + key.offset);
1506 if (total_found > CACHING_CTL_WAKE_UP) {
1507 total_found = 0;
1508 wake_up(&caching_ctl->wait);
1509 }
1510 extent_count++;
1511 }
1512
1513 if (extent_count != expected_extent_count) {
1514 btrfs_err(fs_info,
1515 "incorrect extent count for %llu; counted %u, expected %u",
1516 block_group->start, extent_count,
1517 expected_extent_count);
1518 ASSERT(0);
1519 ret = -EIO;
1520 goto out;
1521 }
1522
1523 caching_ctl->progress = (u64)-1;
1524
1525 ret = 0;
1526 out:
1527 return ret;
1528 }
1529
1530 int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
1531 {
1532 struct btrfs_block_group *block_group;
1533 struct btrfs_free_space_info *info;
1534 struct btrfs_path *path;
1535 u32 extent_count, flags;
1536 int ret;
1537
1538 block_group = caching_ctl->block_group;
1539
1540 path = btrfs_alloc_path();
1541 if (!path)
1542 return -ENOMEM;
1543
1544 /*
1545 * Just like caching_thread() doesn't want to deadlock on the extent
1546 * tree, we don't want to deadlock on the free space tree.
1547 */
1548 path->skip_locking = 1;
1549 path->search_commit_root = 1;
1550 path->reada = READA_FORWARD;
1551
1552 info = search_free_space_info(NULL, block_group, path, 0);
1553 if (IS_ERR(info)) {
1554 ret = PTR_ERR(info);
1555 goto out;
1556 }
1557 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
1558 flags = btrfs_free_space_flags(path->nodes[0], info);
1559
1560 /*
1561 * We left path pointing to the free space info item, so now
1562 * load_free_space_foo can just iterate through the free space tree from
1563 * there.
1564 */
1565 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS)
1566 ret = load_free_space_bitmaps(caching_ctl, path, extent_count);
1567 else
1568 ret = load_free_space_extents(caching_ctl, path, extent_count);
1569
1570 out:
1571 btrfs_free_path(path);
1572 return ret;
1573 }
Linux with added FPC-III support