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Linux 5.8-rc4
[linux/fpc-iii.git] / fs / btrfs / free-space-tree.c
blob8b1f5c8897b750a6c740922e16833117d05ae3e2
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 /*
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->length + bitmap_range - 1, bitmap_range);
31 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
32 total_bitmap_size = num_bitmaps * bitmap_size;
33 cache->bitmap_high_thresh = div_u64(total_bitmap_size,
34 sizeof(struct btrfs_item));
35
36 /*
37 * We allow for a small buffer between the high threshold and low
38 * threshold to avoid thrashing back and forth between the two formats.
39 */
40 if (cache->bitmap_high_thresh > 100)
41 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
42 else
43 cache->bitmap_low_thresh = 0;
44 }
45
46 static int add_new_free_space_info(struct btrfs_trans_handle *trans,
47 struct btrfs_block_group *block_group,
48 struct btrfs_path *path)
49 {
50 struct btrfs_root *root = trans->fs_info->free_space_root;
51 struct btrfs_free_space_info *info;
52 struct btrfs_key key;
53 struct extent_buffer *leaf;
54 int ret;
55
56 key.objectid = block_group->start;
57 key.type = BTRFS_FREE_SPACE_INFO_KEY;
58 key.offset = block_group->length;
59
60 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
61 if (ret)
62 goto out;
63
64 leaf = path->nodes[0];
65 info = btrfs_item_ptr(leaf, path->slots[0],
66 struct btrfs_free_space_info);
67 btrfs_set_free_space_extent_count(leaf, info, 0);
68 btrfs_set_free_space_flags(leaf, info, 0);
69 btrfs_mark_buffer_dirty(leaf);
70
71 ret = 0;
72 out:
73 btrfs_release_path(path);
74 return ret;
75 }
76
77 EXPORT_FOR_TESTS
78 struct btrfs_free_space_info *search_free_space_info(
79 struct btrfs_trans_handle *trans,
80 struct btrfs_block_group *block_group,
81 struct btrfs_path *path, int cow)
82 {
83 struct btrfs_fs_info *fs_info = block_group->fs_info;
84 struct btrfs_root *root = fs_info->free_space_root;
85 struct btrfs_key key;
86 int ret;
87
88 key.objectid = block_group->start;
89 key.type = BTRFS_FREE_SPACE_INFO_KEY;
90 key.offset = block_group->length;
91
92 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
93 if (ret < 0)
94 return ERR_PTR(ret);
95 if (ret != 0) {
96 btrfs_warn(fs_info, "missing free space info for %llu",
97 block_group->start);
98 ASSERT(0);
99 return ERR_PTR(-ENOENT);
100 }
101
102 return btrfs_item_ptr(path->nodes[0], path->slots[0],
103 struct btrfs_free_space_info);
104 }
105
106 /*
107 * btrfs_search_slot() but we're looking for the greatest key less than the
108 * passed key.
109 */
110 static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
111 struct btrfs_root *root,
112 struct btrfs_key *key, struct btrfs_path *p,
113 int ins_len, int cow)
114 {
115 int ret;
116
117 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
118 if (ret < 0)
119 return ret;
120
121 if (ret == 0) {
122 ASSERT(0);
123 return -EIO;
124 }
125
126 if (p->slots[0] == 0) {
127 ASSERT(0);
128 return -EIO;
129 }
130 p->slots[0]--;
131
132 return 0;
133 }
134
135 static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize)
136 {
137 return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
138 }
139
140 static unsigned long *alloc_bitmap(u32 bitmap_size)
141 {
142 unsigned long *ret;
143 unsigned int nofs_flag;
144 u32 bitmap_rounded_size = round_up(bitmap_size, sizeof(unsigned long));
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_rounded_size, GFP_KERNEL);
156 memalloc_nofs_restore(nofs_flag);
157 return ret;
158 }
159
160 static void le_bitmap_set(unsigned long *map, unsigned int start, int len)
161 {
162 u8 *p = ((u8 *)map) + BIT_BYTE(start);
163 const unsigned int size = start + len;
164 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
165 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
166
167 while (len - bits_to_set >= 0) {
168 *p |= mask_to_set;
169 len -= bits_to_set;
170 bits_to_set = BITS_PER_BYTE;
171 mask_to_set = ~0;
172 p++;
173 }
174 if (len) {
175 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
176 *p |= mask_to_set;
177 }
178 }
179
180 EXPORT_FOR_TESTS
181 int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
182 struct btrfs_block_group *block_group,
183 struct btrfs_path *path)
184 {
185 struct btrfs_fs_info *fs_info = trans->fs_info;
186 struct btrfs_root *root = fs_info->free_space_root;
187 struct btrfs_free_space_info *info;
188 struct btrfs_key key, found_key;
189 struct extent_buffer *leaf;
190 unsigned long *bitmap;
191 char *bitmap_cursor;
192 u64 start, end;
193 u64 bitmap_range, i;
194 u32 bitmap_size, flags, expected_extent_count;
195 u32 extent_count = 0;
196 int done = 0, nr;
197 int ret;
198
199 bitmap_size = free_space_bitmap_size(block_group->length,
200 fs_info->sectorsize);
201 bitmap = alloc_bitmap(bitmap_size);
202 if (!bitmap) {
203 ret = -ENOMEM;
204 goto out;
205 }
206
207 start = block_group->start;
208 end = block_group->start + block_group->length;
209
210 key.objectid = end - 1;
211 key.type = (u8)-1;
212 key.offset = (u64)-1;
213
214 while (!done) {
215 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
216 if (ret)
217 goto out;
218
219 leaf = path->nodes[0];
220 nr = 0;
221 path->slots[0]++;
222 while (path->slots[0] > 0) {
223 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
224
225 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
226 ASSERT(found_key.objectid == block_group->start);
227 ASSERT(found_key.offset == block_group->length);
228 done = 1;
229 break;
230 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
231 u64 first, last;
232
233 ASSERT(found_key.objectid >= start);
234 ASSERT(found_key.objectid < end);
235 ASSERT(found_key.objectid + found_key.offset <= end);
236
237 first = div_u64(found_key.objectid - start,
238 fs_info->sectorsize);
239 last = div_u64(found_key.objectid + found_key.offset - start,
240 fs_info->sectorsize);
241 le_bitmap_set(bitmap, first, last - first);
242
243 extent_count++;
244 nr++;
245 path->slots[0]--;
246 } else {
247 ASSERT(0);
248 }
249 }
250
251 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
252 if (ret)
253 goto out;
254 btrfs_release_path(path);
255 }
256
257 info = search_free_space_info(trans, block_group, path, 1);
258 if (IS_ERR(info)) {
259 ret = PTR_ERR(info);
260 goto out;
261 }
262 leaf = path->nodes[0];
263 flags = btrfs_free_space_flags(leaf, info);
264 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
265 btrfs_set_free_space_flags(leaf, info, flags);
266 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
267 btrfs_mark_buffer_dirty(leaf);
268 btrfs_release_path(path);
269
270 if (extent_count != expected_extent_count) {
271 btrfs_err(fs_info,
272 "incorrect extent count for %llu; counted %u, expected %u",
273 block_group->start, extent_count,
274 expected_extent_count);
275 ASSERT(0);
276 ret = -EIO;
277 goto out;
278 }
279
280 bitmap_cursor = (char *)bitmap;
281 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
282 i = start;
283 while (i < end) {
284 unsigned long ptr;
285 u64 extent_size;
286 u32 data_size;
287
288 extent_size = min(end - i, bitmap_range);
289 data_size = free_space_bitmap_size(extent_size,
290 fs_info->sectorsize);
291
292 key.objectid = i;
293 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
294 key.offset = extent_size;
295
296 ret = btrfs_insert_empty_item(trans, root, path, &key,
297 data_size);
298 if (ret)
299 goto out;
300
301 leaf = path->nodes[0];
302 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
303 write_extent_buffer(leaf, bitmap_cursor, ptr,
304 data_size);
305 btrfs_mark_buffer_dirty(leaf);
306 btrfs_release_path(path);
307
308 i += extent_size;
309 bitmap_cursor += data_size;
310 }
311
312 ret = 0;
313 out:
314 kvfree(bitmap);
315 if (ret)
316 btrfs_abort_transaction(trans, ret);
317 return ret;
318 }
319
320 EXPORT_FOR_TESTS
321 int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
322 struct btrfs_block_group *block_group,
323 struct btrfs_path *path)
324 {
325 struct btrfs_fs_info *fs_info = trans->fs_info;
326 struct btrfs_root *root = fs_info->free_space_root;
327 struct btrfs_free_space_info *info;
328 struct btrfs_key key, found_key;
329 struct extent_buffer *leaf;
330 unsigned long *bitmap;
331 u64 start, end;
332 u32 bitmap_size, flags, expected_extent_count;
333 unsigned long nrbits, start_bit, end_bit;
334 u32 extent_count = 0;
335 int done = 0, nr;
336 int ret;
337
338 bitmap_size = free_space_bitmap_size(block_group->length,
339 fs_info->sectorsize);
340 bitmap = alloc_bitmap(bitmap_size);
341 if (!bitmap) {
342 ret = -ENOMEM;
343 goto out;
344 }
345
346 start = block_group->start;
347 end = block_group->start + block_group->length;
348
349 key.objectid = end - 1;
350 key.type = (u8)-1;
351 key.offset = (u64)-1;
352
353 while (!done) {
354 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
355 if (ret)
356 goto out;
357
358 leaf = path->nodes[0];
359 nr = 0;
360 path->slots[0]++;
361 while (path->slots[0] > 0) {
362 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
363
364 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
365 ASSERT(found_key.objectid == block_group->start);
366 ASSERT(found_key.offset == block_group->length);
367 done = 1;
368 break;
369 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
370 unsigned long ptr;
371 char *bitmap_cursor;
372 u32 bitmap_pos, data_size;
373
374 ASSERT(found_key.objectid >= start);
375 ASSERT(found_key.objectid < end);
376 ASSERT(found_key.objectid + found_key.offset <= end);
377
378 bitmap_pos = div_u64(found_key.objectid - start,
379 fs_info->sectorsize *
380 BITS_PER_BYTE);
381 bitmap_cursor = ((char *)bitmap) + bitmap_pos;
382 data_size = free_space_bitmap_size(found_key.offset,
383 fs_info->sectorsize);
384
385 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
386 read_extent_buffer(leaf, bitmap_cursor, ptr,
387 data_size);
388
389 nr++;
390 path->slots[0]--;
391 } else {
392 ASSERT(0);
393 }
394 }
395
396 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
397 if (ret)
398 goto out;
399 btrfs_release_path(path);
400 }
401
402 info = search_free_space_info(trans, block_group, path, 1);
403 if (IS_ERR(info)) {
404 ret = PTR_ERR(info);
405 goto out;
406 }
407 leaf = path->nodes[0];
408 flags = btrfs_free_space_flags(leaf, info);
409 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
410 btrfs_set_free_space_flags(leaf, info, flags);
411 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
412 btrfs_mark_buffer_dirty(leaf);
413 btrfs_release_path(path);
414
415 nrbits = div_u64(block_group->length, block_group->fs_info->sectorsize);
416 start_bit = find_next_bit_le(bitmap, nrbits, 0);
417
418 while (start_bit < nrbits) {
419 end_bit = find_next_zero_bit_le(bitmap, nrbits, start_bit);
420 ASSERT(start_bit < end_bit);
421
422 key.objectid = start + start_bit * block_group->fs_info->sectorsize;
423 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
424 key.offset = (end_bit - start_bit) * block_group->fs_info->sectorsize;
425
426 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
427 if (ret)
428 goto out;
429 btrfs_release_path(path);
430
431 extent_count++;
432
433 start_bit = find_next_bit_le(bitmap, nrbits, end_bit);
434 }
435
436 if (extent_count != expected_extent_count) {
437 btrfs_err(fs_info,
438 "incorrect extent count for %llu; counted %u, expected %u",
439 block_group->start, extent_count,
440 expected_extent_count);
441 ASSERT(0);
442 ret = -EIO;
443 goto out;
444 }
445
446 ret = 0;
447 out:
448 kvfree(bitmap);
449 if (ret)
450 btrfs_abort_transaction(trans, ret);
451 return ret;
452 }
453
454 static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
455 struct btrfs_block_group *block_group,
456 struct btrfs_path *path,
457 int new_extents)
458 {
459 struct btrfs_free_space_info *info;
460 u32 flags;
461 u32 extent_count;
462 int ret = 0;
463
464 if (new_extents == 0)
465 return 0;
466
467 info = search_free_space_info(trans, block_group, path, 1);
468 if (IS_ERR(info)) {
469 ret = PTR_ERR(info);
470 goto out;
471 }
472 flags = btrfs_free_space_flags(path->nodes[0], info);
473 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
474
475 extent_count += new_extents;
476 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
477 btrfs_mark_buffer_dirty(path->nodes[0]);
478 btrfs_release_path(path);
479
480 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
481 extent_count > block_group->bitmap_high_thresh) {
482 ret = convert_free_space_to_bitmaps(trans, block_group, path);
483 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
484 extent_count < block_group->bitmap_low_thresh) {
485 ret = convert_free_space_to_extents(trans, block_group, path);
486 }
487
488 out:
489 return ret;
490 }
491
492 EXPORT_FOR_TESTS
493 int free_space_test_bit(struct btrfs_block_group *block_group,
494 struct btrfs_path *path, u64 offset)
495 {
496 struct extent_buffer *leaf;
497 struct btrfs_key key;
498 u64 found_start, found_end;
499 unsigned long ptr, i;
500
501 leaf = path->nodes[0];
502 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
503 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
504
505 found_start = key.objectid;
506 found_end = key.objectid + key.offset;
507 ASSERT(offset >= found_start && offset < found_end);
508
509 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
510 i = div_u64(offset - found_start,
511 block_group->fs_info->sectorsize);
512 return !!extent_buffer_test_bit(leaf, ptr, i);
513 }
514
515 static void free_space_set_bits(struct btrfs_block_group *block_group,
516 struct btrfs_path *path, u64 *start, u64 *size,
517 int bit)
518 {
519 struct btrfs_fs_info *fs_info = block_group->fs_info;
520 struct extent_buffer *leaf;
521 struct btrfs_key key;
522 u64 end = *start + *size;
523 u64 found_start, found_end;
524 unsigned long ptr, first, last;
525
526 leaf = path->nodes[0];
527 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
528 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
529
530 found_start = key.objectid;
531 found_end = key.objectid + key.offset;
532 ASSERT(*start >= found_start && *start < found_end);
533 ASSERT(end > found_start);
534
535 if (end > found_end)
536 end = found_end;
537
538 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
539 first = div_u64(*start - found_start, fs_info->sectorsize);
540 last = div_u64(end - found_start, fs_info->sectorsize);
541 if (bit)
542 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
543 else
544 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
545 btrfs_mark_buffer_dirty(leaf);
546
547 *size -= end - *start;
548 *start = end;
549 }
550
551 /*
552 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
553 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
554 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
555 * looking for.
556 */
557 static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
558 struct btrfs_root *root, struct btrfs_path *p)
559 {
560 struct btrfs_key key;
561
562 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
563 p->slots[0]++;
564 return 0;
565 }
566
567 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
568 btrfs_release_path(p);
569
570 key.objectid += key.offset;
571 key.type = (u8)-1;
572 key.offset = (u64)-1;
573
574 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
575 }
576
577 /*
578 * If remove is 1, then we are removing free space, thus clearing bits in the
579 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
580 * the bitmap.
581 */
582 static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
583 struct btrfs_block_group *block_group,
584 struct btrfs_path *path,
585 u64 start, u64 size, int remove)
586 {
587 struct btrfs_root *root = block_group->fs_info->free_space_root;
588 struct btrfs_key key;
589 u64 end = start + size;
590 u64 cur_start, cur_size;
591 int prev_bit, next_bit;
592 int new_extents;
593 int ret;
594
595 /*
596 * Read the bit for the block immediately before the extent of space if
597 * that block is within the block group.
598 */
599 if (start > block_group->start) {
600 u64 prev_block = start - block_group->fs_info->sectorsize;
601
602 key.objectid = prev_block;
603 key.type = (u8)-1;
604 key.offset = (u64)-1;
605
606 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
607 if (ret)
608 goto out;
609
610 prev_bit = free_space_test_bit(block_group, path, prev_block);
611
612 /* The previous block may have been in the previous bitmap. */
613 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
614 if (start >= key.objectid + key.offset) {
615 ret = free_space_next_bitmap(trans, root, path);
616 if (ret)
617 goto out;
618 }
619 } else {
620 key.objectid = start;
621 key.type = (u8)-1;
622 key.offset = (u64)-1;
623
624 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
625 if (ret)
626 goto out;
627
628 prev_bit = -1;
629 }
630
631 /*
632 * Iterate over all of the bitmaps overlapped by the extent of space,
633 * clearing/setting bits as required.
634 */
635 cur_start = start;
636 cur_size = size;
637 while (1) {
638 free_space_set_bits(block_group, path, &cur_start, &cur_size,
639 !remove);
640 if (cur_size == 0)
641 break;
642 ret = free_space_next_bitmap(trans, root, path);
643 if (ret)
644 goto out;
645 }
646
647 /*
648 * Read the bit for the block immediately after the extent of space if
649 * that block is within the block group.
650 */
651 if (end < block_group->start + block_group->length) {
652 /* The next block may be in the next bitmap. */
653 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
654 if (end >= key.objectid + key.offset) {
655 ret = free_space_next_bitmap(trans, root, path);
656 if (ret)
657 goto out;
658 }
659
660 next_bit = free_space_test_bit(block_group, path, end);
661 } else {
662 next_bit = -1;
663 }
664
665 if (remove) {
666 new_extents = -1;
667 if (prev_bit == 1) {
668 /* Leftover on the left. */
669 new_extents++;
670 }
671 if (next_bit == 1) {
672 /* Leftover on the right. */
673 new_extents++;
674 }
675 } else {
676 new_extents = 1;
677 if (prev_bit == 1) {
678 /* Merging with neighbor on the left. */
679 new_extents--;
680 }
681 if (next_bit == 1) {
682 /* Merging with neighbor on the right. */
683 new_extents--;
684 }
685 }
686
687 btrfs_release_path(path);
688 ret = update_free_space_extent_count(trans, block_group, path,
689 new_extents);
690
691 out:
692 return ret;
693 }
694
695 static int remove_free_space_extent(struct btrfs_trans_handle *trans,
696 struct btrfs_block_group *block_group,
697 struct btrfs_path *path,
698 u64 start, u64 size)
699 {
700 struct btrfs_root *root = trans->fs_info->free_space_root;
701 struct btrfs_key key;
702 u64 found_start, found_end;
703 u64 end = start + size;
704 int new_extents = -1;
705 int ret;
706
707 key.objectid = start;
708 key.type = (u8)-1;
709 key.offset = (u64)-1;
710
711 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
712 if (ret)
713 goto out;
714
715 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
716
717 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
718
719 found_start = key.objectid;
720 found_end = key.objectid + key.offset;
721 ASSERT(start >= found_start && end <= found_end);
722
723 /*
724 * Okay, now that we've found the free space extent which contains the
725 * free space that we are removing, there are four cases:
726 *
727 * 1. We're using the whole extent: delete the key we found and
728 * decrement the free space extent count.
729 * 2. We are using part of the extent starting at the beginning: delete
730 * the key we found and insert a new key representing the leftover at
731 * the end. There is no net change in the number of extents.
732 * 3. We are using part of the extent ending at the end: delete the key
733 * we found and insert a new key representing the leftover at the
734 * beginning. There is no net change in the number of extents.
735 * 4. We are using part of the extent in the middle: delete the key we
736 * found and insert two new keys representing the leftovers on each
737 * side. Where we used to have one extent, we now have two, so increment
738 * the extent count. We may need to convert the block group to bitmaps
739 * as a result.
740 */
741
742 /* Delete the existing key (cases 1-4). */
743 ret = btrfs_del_item(trans, root, path);
744 if (ret)
745 goto out;
746
747 /* Add a key for leftovers at the beginning (cases 3 and 4). */
748 if (start > found_start) {
749 key.objectid = found_start;
750 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
751 key.offset = start - found_start;
752
753 btrfs_release_path(path);
754 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
755 if (ret)
756 goto out;
757 new_extents++;
758 }
759
760 /* Add a key for leftovers at the end (cases 2 and 4). */
761 if (end < found_end) {
762 key.objectid = end;
763 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
764 key.offset = found_end - end;
765
766 btrfs_release_path(path);
767 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
768 if (ret)
769 goto out;
770 new_extents++;
771 }
772
773 btrfs_release_path(path);
774 ret = update_free_space_extent_count(trans, block_group, path,
775 new_extents);
776
777 out:
778 return ret;
779 }
780
781 EXPORT_FOR_TESTS
782 int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
783 struct btrfs_block_group *block_group,
784 struct btrfs_path *path, u64 start, u64 size)
785 {
786 struct btrfs_free_space_info *info;
787 u32 flags;
788 int ret;
789
790 if (block_group->needs_free_space) {
791 ret = __add_block_group_free_space(trans, block_group, path);
792 if (ret)
793 return ret;
794 }
795
796 info = search_free_space_info(NULL, block_group, path, 0);
797 if (IS_ERR(info))
798 return PTR_ERR(info);
799 flags = btrfs_free_space_flags(path->nodes[0], info);
800 btrfs_release_path(path);
801
802 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
803 return modify_free_space_bitmap(trans, block_group, path,
804 start, size, 1);
805 } else {
806 return remove_free_space_extent(trans, block_group, path,
807 start, size);
808 }
809 }
810
811 int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
812 u64 start, u64 size)
813 {
814 struct btrfs_block_group *block_group;
815 struct btrfs_path *path;
816 int ret;
817
818 if (!btrfs_fs_compat_ro(trans->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(trans->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, block_group, path, start,
836 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_block_group *block_group,
849 struct btrfs_path *path,
850 u64 start, u64 size)
851 {
852 struct btrfs_root *root = trans->fs_info->free_space_root;
853 struct btrfs_key key, new_key;
854 u64 found_start, found_end;
855 u64 end = start + size;
856 int new_extents = 1;
857 int ret;
858
859 /*
860 * We are adding a new extent of free space, but we need to merge
861 * extents. There are four cases here:
862 *
863 * 1. The new extent does not have any immediate neighbors to merge
864 * with: add the new key and increment the free space extent count. We
865 * may need to convert the block group to bitmaps as a result.
866 * 2. The new extent has an immediate neighbor before it: remove the
867 * previous key and insert a new key combining both of them. There is no
868 * net change in the number of extents.
869 * 3. The new extent has an immediate neighbor after it: remove the next
870 * key and insert a new key combining both of them. There is no net
871 * change in the number of extents.
872 * 4. The new extent has immediate neighbors on both sides: remove both
873 * of the keys and insert a new key combining all of them. Where we used
874 * to have two extents, we now have one, so decrement the extent count.
875 */
876
877 new_key.objectid = start;
878 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
879 new_key.offset = size;
880
881 /* Search for a neighbor on the left. */
882 if (start == block_group->start)
883 goto right;
884 key.objectid = start - 1;
885 key.type = (u8)-1;
886 key.offset = (u64)-1;
887
888 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
889 if (ret)
890 goto out;
891
892 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
893
894 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
895 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
896 btrfs_release_path(path);
897 goto right;
898 }
899
900 found_start = key.objectid;
901 found_end = key.objectid + key.offset;
902 ASSERT(found_start >= block_group->start &&
903 found_end > block_group->start);
904 ASSERT(found_start < start && found_end <= start);
905
906 /*
907 * Delete the neighbor on the left and absorb it into the new key (cases
908 * 2 and 4).
909 */
910 if (found_end == start) {
911 ret = btrfs_del_item(trans, root, path);
912 if (ret)
913 goto out;
914 new_key.objectid = found_start;
915 new_key.offset += key.offset;
916 new_extents--;
917 }
918 btrfs_release_path(path);
919
920 right:
921 /* Search for a neighbor on the right. */
922 if (end == block_group->start + block_group->length)
923 goto insert;
924 key.objectid = end;
925 key.type = (u8)-1;
926 key.offset = (u64)-1;
927
928 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
929 if (ret)
930 goto out;
931
932 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
933
934 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
935 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
936 btrfs_release_path(path);
937 goto insert;
938 }
939
940 found_start = key.objectid;
941 found_end = key.objectid + key.offset;
942 ASSERT(found_start >= block_group->start &&
943 found_end > block_group->start);
944 ASSERT((found_start < start && found_end <= start) ||
945 (found_start >= end && found_end > end));
946
947 /*
948 * Delete the neighbor on the right and absorb it into the new key
949 * (cases 3 and 4).
950 */
951 if (found_start == end) {
952 ret = btrfs_del_item(trans, root, path);
953 if (ret)
954 goto out;
955 new_key.offset += key.offset;
956 new_extents--;
957 }
958 btrfs_release_path(path);
959
960 insert:
961 /* Insert the new key (cases 1-4). */
962 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
963 if (ret)
964 goto out;
965
966 btrfs_release_path(path);
967 ret = update_free_space_extent_count(trans, block_group, path,
968 new_extents);
969
970 out:
971 return ret;
972 }
973
974 EXPORT_FOR_TESTS
975 int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
976 struct btrfs_block_group *block_group,
977 struct btrfs_path *path, u64 start, u64 size)
978 {
979 struct btrfs_free_space_info *info;
980 u32 flags;
981 int ret;
982
983 if (block_group->needs_free_space) {
984 ret = __add_block_group_free_space(trans, block_group, path);
985 if (ret)
986 return ret;
987 }
988
989 info = search_free_space_info(NULL, block_group, path, 0);
990 if (IS_ERR(info))
991 return PTR_ERR(info);
992 flags = btrfs_free_space_flags(path->nodes[0], info);
993 btrfs_release_path(path);
994
995 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
996 return modify_free_space_bitmap(trans, block_group, path,
997 start, size, 0);
998 } else {
999 return add_free_space_extent(trans, block_group, path, start,
1000 size);
1001 }
1002 }
1003
1004 int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1005 u64 start, u64 size)
1006 {
1007 struct btrfs_block_group *block_group;
1008 struct btrfs_path *path;
1009 int ret;
1010
1011 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1012 return 0;
1013
1014 path = btrfs_alloc_path();
1015 if (!path) {
1016 ret = -ENOMEM;
1017 goto out;
1018 }
1019
1020 block_group = btrfs_lookup_block_group(trans->fs_info, start);
1021 if (!block_group) {
1022 ASSERT(0);
1023 ret = -ENOENT;
1024 goto out;
1025 }
1026
1027 mutex_lock(&block_group->free_space_lock);
1028 ret = __add_to_free_space_tree(trans, block_group, path, start, size);
1029 mutex_unlock(&block_group->free_space_lock);
1030
1031 btrfs_put_block_group(block_group);
1032 out:
1033 btrfs_free_path(path);
1034 if (ret)
1035 btrfs_abort_transaction(trans, ret);
1036 return ret;
1037 }
1038
1039 /*
1040 * Populate the free space tree by walking the extent tree. Operations on the
1041 * extent tree that happen as a result of writes to the free space tree will go
1042 * through the normal add/remove hooks.
1043 */
1044 static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1045 struct btrfs_block_group *block_group)
1046 {
1047 struct btrfs_root *extent_root = trans->fs_info->extent_root;
1048 struct btrfs_path *path, *path2;
1049 struct btrfs_key key;
1050 u64 start, end;
1051 int ret;
1052
1053 path = btrfs_alloc_path();
1054 if (!path)
1055 return -ENOMEM;
1056 path->reada = READA_FORWARD;
1057
1058 path2 = btrfs_alloc_path();
1059 if (!path2) {
1060 btrfs_free_path(path);
1061 return -ENOMEM;
1062 }
1063
1064 ret = add_new_free_space_info(trans, block_group, path2);
1065 if (ret)
1066 goto out;
1067
1068 mutex_lock(&block_group->free_space_lock);
1069
1070 /*
1071 * Iterate through all of the extent and metadata items in this block
1072 * group, adding the free space between them and the free space at the
1073 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1074 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1075 * contained in.
1076 */
1077 key.objectid = block_group->start;
1078 key.type = BTRFS_EXTENT_ITEM_KEY;
1079 key.offset = 0;
1080
1081 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1082 if (ret < 0)
1083 goto out_locked;
1084 ASSERT(ret == 0);
1085
1086 start = block_group->start;
1087 end = block_group->start + block_group->length;
1088 while (1) {
1089 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1090
1091 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1092 key.type == BTRFS_METADATA_ITEM_KEY) {
1093 if (key.objectid >= end)
1094 break;
1095
1096 if (start < key.objectid) {
1097 ret = __add_to_free_space_tree(trans,
1098 block_group,
1099 path2, start,
1100 key.objectid -
1101 start);
1102 if (ret)
1103 goto out_locked;
1104 }
1105 start = key.objectid;
1106 if (key.type == BTRFS_METADATA_ITEM_KEY)
1107 start += trans->fs_info->nodesize;
1108 else
1109 start += key.offset;
1110 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1111 if (key.objectid != block_group->start)
1112 break;
1113 }
1114
1115 ret = btrfs_next_item(extent_root, path);
1116 if (ret < 0)
1117 goto out_locked;
1118 if (ret)
1119 break;
1120 }
1121 if (start < end) {
1122 ret = __add_to_free_space_tree(trans, block_group, path2,
1123 start, end - start);
1124 if (ret)
1125 goto out_locked;
1126 }
1127
1128 ret = 0;
1129 out_locked:
1130 mutex_unlock(&block_group->free_space_lock);
1131 out:
1132 btrfs_free_path(path2);
1133 btrfs_free_path(path);
1134 return ret;
1135 }
1136
1137 int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1138 {
1139 struct btrfs_trans_handle *trans;
1140 struct btrfs_root *tree_root = fs_info->tree_root;
1141 struct btrfs_root *free_space_root;
1142 struct btrfs_block_group *block_group;
1143 struct rb_node *node;
1144 int ret;
1145
1146 trans = btrfs_start_transaction(tree_root, 0);
1147 if (IS_ERR(trans))
1148 return PTR_ERR(trans);
1149
1150 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1151 free_space_root = btrfs_create_tree(trans,
1152 BTRFS_FREE_SPACE_TREE_OBJECTID);
1153 if (IS_ERR(free_space_root)) {
1154 ret = PTR_ERR(free_space_root);
1155 goto abort;
1156 }
1157 fs_info->free_space_root = free_space_root;
1158
1159 node = rb_first(&fs_info->block_group_cache_tree);
1160 while (node) {
1161 block_group = rb_entry(node, struct btrfs_block_group,
1162 cache_node);
1163 ret = populate_free_space_tree(trans, block_group);
1164 if (ret)
1165 goto abort;
1166 node = rb_next(node);
1167 }
1168
1169 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1170 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1171 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1172
1173 return btrfs_commit_transaction(trans);
1174
1175 abort:
1176 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1177 btrfs_abort_transaction(trans, ret);
1178 btrfs_end_transaction(trans);
1179 return ret;
1180 }
1181
1182 static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1183 struct btrfs_root *root)
1184 {
1185 struct btrfs_path *path;
1186 struct btrfs_key key;
1187 int nr;
1188 int ret;
1189
1190 path = btrfs_alloc_path();
1191 if (!path)
1192 return -ENOMEM;
1193
1194 path->leave_spinning = 1;
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