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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 "messages.h"
9#include "ctree.h"
10#include "disk-io.h"
11#include "locking.h"
12#include "free-space-tree.h"
13#include "transaction.h"
14#include "block-group.h"
15#include "fs.h"
16#include "accessors.h"
17#include "extent-tree.h"
18#include "root-tree.h"
19
20static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
21 struct btrfs_block_group *block_group,
22 struct btrfs_path *path);
23
24static struct btrfs_root *btrfs_free_space_root(
25 struct btrfs_block_group *block_group)
26{
27 struct btrfs_key key = {
28 .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID,
29 .type = BTRFS_ROOT_ITEM_KEY,
30 .offset = 0,
31 };
32
33 if (btrfs_fs_incompat(block_group->fs_info, EXTENT_TREE_V2))
34 key.offset = block_group->global_root_id;
35 return btrfs_global_root(block_group->fs_info, &key);
36}
37
38void set_free_space_tree_thresholds(struct btrfs_block_group *cache)
39{
40 u32 bitmap_range;
41 size_t bitmap_size;
42 u64 num_bitmaps, total_bitmap_size;
43
44 if (WARN_ON(cache->length == 0))
45 btrfs_warn(cache->fs_info, "block group %llu length is zero",
46 cache->start);
47
48 /*
49 * We convert to bitmaps when the disk space required for using extents
50 * exceeds that required for using bitmaps.
51 */
52 bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
53 num_bitmaps = div_u64(cache->length + bitmap_range - 1, bitmap_range);
54 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
55 total_bitmap_size = num_bitmaps * bitmap_size;
56 cache->bitmap_high_thresh = div_u64(total_bitmap_size,
57 sizeof(struct btrfs_item));
58
59 /*
60 * We allow for a small buffer between the high threshold and low
61 * threshold to avoid thrashing back and forth between the two formats.
62 */
63 if (cache->bitmap_high_thresh > 100)
64 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
65 else
66 cache->bitmap_low_thresh = 0;
67}
68
69static int add_new_free_space_info(struct btrfs_trans_handle *trans,
70 struct btrfs_block_group *block_group,
71 struct btrfs_path *path)
72{
73 struct btrfs_root *root = btrfs_free_space_root(block_group);
74 struct btrfs_free_space_info *info;
75 struct btrfs_key key;
76 struct extent_buffer *leaf;
77 int ret;
78
79 key.objectid = block_group->start;
80 key.type = BTRFS_FREE_SPACE_INFO_KEY;
81 key.offset = block_group->length;
82
83 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
84 if (ret)
85 goto out;
86
87 leaf = path->nodes[0];
88 info = btrfs_item_ptr(leaf, path->slots[0],
89 struct btrfs_free_space_info);
90 btrfs_set_free_space_extent_count(leaf, info, 0);
91 btrfs_set_free_space_flags(leaf, info, 0);
92 btrfs_mark_buffer_dirty(trans, leaf);
93
94 ret = 0;
95out:
96 btrfs_release_path(path);
97 return ret;
98}
99
100EXPORT_FOR_TESTS
101struct btrfs_free_space_info *search_free_space_info(
102 struct btrfs_trans_handle *trans,
103 struct btrfs_block_group *block_group,
104 struct btrfs_path *path, int cow)
105{
106 struct btrfs_fs_info *fs_info = block_group->fs_info;
107 struct btrfs_root *root = btrfs_free_space_root(block_group);
108 struct btrfs_key key;
109 int ret;
110
111 key.objectid = block_group->start;
112 key.type = BTRFS_FREE_SPACE_INFO_KEY;
113 key.offset = block_group->length;
114
115 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
116 if (ret < 0)
117 return ERR_PTR(ret);
118 if (ret != 0) {
119 btrfs_warn(fs_info, "missing free space info for %llu",
120 block_group->start);
121 ASSERT(0);
122 return ERR_PTR(-ENOENT);
123 }
124
125 return btrfs_item_ptr(path->nodes[0], path->slots[0],
126 struct btrfs_free_space_info);
127}
128
129/*
130 * btrfs_search_slot() but we're looking for the greatest key less than the
131 * passed key.
132 */
133static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
134 struct btrfs_root *root,
135 struct btrfs_key *key, struct btrfs_path *p,
136 int ins_len, int cow)
137{
138 int ret;
139
140 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
141 if (ret < 0)
142 return ret;
143
144 if (ret == 0) {
145 ASSERT(0);
146 return -EIO;
147 }
148
149 if (p->slots[0] == 0) {
150 ASSERT(0);
151 return -EIO;
152 }
153 p->slots[0]--;
154
155 return 0;
156}
157
158static inline u32 free_space_bitmap_size(const struct btrfs_fs_info *fs_info,
159 u64 size)
160{
161 return DIV_ROUND_UP(size >> fs_info->sectorsize_bits, BITS_PER_BYTE);
162}
163
164static unsigned long *alloc_bitmap(u32 bitmap_size)
165{
166 unsigned long *ret;
167 unsigned int nofs_flag;
168 u32 bitmap_rounded_size = round_up(bitmap_size, sizeof(unsigned long));
169
170 /*
171 * GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse
172 * into the filesystem as the free space bitmap can be modified in the
173 * critical section of a transaction commit.
174 *
175 * TODO: push the memalloc_nofs_{save,restore}() to the caller where we
176 * know that recursion is unsafe.
177 */
178 nofs_flag = memalloc_nofs_save();
179 ret = kvzalloc(bitmap_rounded_size, GFP_KERNEL);
180 memalloc_nofs_restore(nofs_flag);
181 return ret;
182}
183
184static void le_bitmap_set(unsigned long *map, unsigned int start, int len)
185{
186 u8 *p = ((u8 *)map) + BIT_BYTE(start);
187 const unsigned int size = start + len;
188 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
189 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
190
191 while (len - bits_to_set >= 0) {
192 *p |= mask_to_set;
193 len -= bits_to_set;
194 bits_to_set = BITS_PER_BYTE;
195 mask_to_set = ~0;
196 p++;
197 }
198 if (len) {
199 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
200 *p |= mask_to_set;
201 }
202}
203
204EXPORT_FOR_TESTS
205int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
206 struct btrfs_block_group *block_group,
207 struct btrfs_path *path)
208{
209 struct btrfs_fs_info *fs_info = trans->fs_info;
210 struct btrfs_root *root = btrfs_free_space_root(block_group);
211 struct btrfs_free_space_info *info;
212 struct btrfs_key key, found_key;
213 struct extent_buffer *leaf;
214 unsigned long *bitmap;
215 char *bitmap_cursor;
216 u64 start, end;
217 u64 bitmap_range, i;
218 u32 bitmap_size, flags, expected_extent_count;
219 u32 extent_count = 0;
220 int done = 0, nr;
221 int ret;
222
223 bitmap_size = free_space_bitmap_size(fs_info, block_group->length);
224 bitmap = alloc_bitmap(bitmap_size);
225 if (!bitmap) {
226 ret = -ENOMEM;
227 goto out;
228 }
229
230 start = block_group->start;
231 end = block_group->start + block_group->length;
232
233 key.objectid = end - 1;
234 key.type = (u8)-1;
235 key.offset = (u64)-1;
236
237 while (!done) {
238 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
239 if (ret)
240 goto out;
241
242 leaf = path->nodes[0];
243 nr = 0;
244 path->slots[0]++;
245 while (path->slots[0] > 0) {
246 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
247
248 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
249 ASSERT(found_key.objectid == block_group->start);
250 ASSERT(found_key.offset == block_group->length);
251 done = 1;
252 break;
253 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
254 u64 first, last;
255
256 ASSERT(found_key.objectid >= start);
257 ASSERT(found_key.objectid < end);
258 ASSERT(found_key.objectid + found_key.offset <= end);
259
260 first = div_u64(found_key.objectid - start,
261 fs_info->sectorsize);
262 last = div_u64(found_key.objectid + found_key.offset - start,
263 fs_info->sectorsize);
264 le_bitmap_set(bitmap, first, last - first);
265
266 extent_count++;
267 nr++;
268 path->slots[0]--;
269 } else {
270 ASSERT(0);
271 }
272 }
273
274 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
275 if (ret)
276 goto out;
277 btrfs_release_path(path);
278 }
279
280 info = search_free_space_info(trans, block_group, path, 1);
281 if (IS_ERR(info)) {
282 ret = PTR_ERR(info);
283 goto out;
284 }
285 leaf = path->nodes[0];
286 flags = btrfs_free_space_flags(leaf, info);
287 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
288 btrfs_set_free_space_flags(leaf, info, flags);
289 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
290 btrfs_mark_buffer_dirty(trans, leaf);
291 btrfs_release_path(path);
292
293 if (extent_count != expected_extent_count) {
294 btrfs_err(fs_info,
295 "incorrect extent count for %llu; counted %u, expected %u",
296 block_group->start, extent_count,
297 expected_extent_count);
298 ASSERT(0);
299 ret = -EIO;
300 goto out;
301 }
302
303 bitmap_cursor = (char *)bitmap;
304 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
305 i = start;
306 while (i < end) {
307 unsigned long ptr;
308 u64 extent_size;
309 u32 data_size;
310
311 extent_size = min(end - i, bitmap_range);
312 data_size = free_space_bitmap_size(fs_info, extent_size);
313
314 key.objectid = i;
315 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
316 key.offset = extent_size;
317
318 ret = btrfs_insert_empty_item(trans, root, path, &key,
319 data_size);
320 if (ret)
321 goto out;
322
323 leaf = path->nodes[0];
324 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
325 write_extent_buffer(leaf, bitmap_cursor, ptr,
326 data_size);
327 btrfs_mark_buffer_dirty(trans, leaf);
328 btrfs_release_path(path);
329
330 i += extent_size;
331 bitmap_cursor += data_size;
332 }
333
334 ret = 0;
335out:
336 kvfree(bitmap);
337 if (ret)
338 btrfs_abort_transaction(trans, ret);
339 return ret;
340}
341
342EXPORT_FOR_TESTS
343int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
344 struct btrfs_block_group *block_group,
345 struct btrfs_path *path)
346{
347 struct btrfs_fs_info *fs_info = trans->fs_info;
348 struct btrfs_root *root = btrfs_free_space_root(block_group);
349 struct btrfs_free_space_info *info;
350 struct btrfs_key key, found_key;
351 struct extent_buffer *leaf;
352 unsigned long *bitmap;
353 u64 start, end;
354 u32 bitmap_size, flags, expected_extent_count;
355 unsigned long nrbits, start_bit, end_bit;
356 u32 extent_count = 0;
357 int done = 0, nr;
358 int ret;
359
360 bitmap_size = free_space_bitmap_size(fs_info, block_group->length);
361 bitmap = alloc_bitmap(bitmap_size);
362 if (!bitmap) {
363 ret = -ENOMEM;
364 goto out;
365 }
366
367 start = block_group->start;
368 end = block_group->start + block_group->length;
369
370 key.objectid = end - 1;
371 key.type = (u8)-1;
372 key.offset = (u64)-1;
373
374 while (!done) {
375 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
376 if (ret)
377 goto out;
378
379 leaf = path->nodes[0];
380 nr = 0;
381 path->slots[0]++;
382 while (path->slots[0] > 0) {
383 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
384
385 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
386 ASSERT(found_key.objectid == block_group->start);
387 ASSERT(found_key.offset == block_group->length);
388 done = 1;
389 break;
390 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
391 unsigned long ptr;
392 char *bitmap_cursor;
393 u32 bitmap_pos, data_size;
394
395 ASSERT(found_key.objectid >= start);
396 ASSERT(found_key.objectid < end);
397 ASSERT(found_key.objectid + found_key.offset <= end);
398
399 bitmap_pos = div_u64(found_key.objectid - start,
400 fs_info->sectorsize *
401 BITS_PER_BYTE);
402 bitmap_cursor = ((char *)bitmap) + bitmap_pos;
403 data_size = free_space_bitmap_size(fs_info,
404 found_key.offset);
405
406 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
407 read_extent_buffer(leaf, bitmap_cursor, ptr,
408 data_size);
409
410 nr++;
411 path->slots[0]--;
412 } else {
413 ASSERT(0);
414 }
415 }
416
417 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
418 if (ret)
419 goto out;
420 btrfs_release_path(path);
421 }
422
423 info = search_free_space_info(trans, block_group, path, 1);
424 if (IS_ERR(info)) {
425 ret = PTR_ERR(info);
426 goto out;
427 }
428 leaf = path->nodes[0];
429 flags = btrfs_free_space_flags(leaf, info);
430 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
431 btrfs_set_free_space_flags(leaf, info, flags);
432 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
433 btrfs_mark_buffer_dirty(trans, leaf);
434 btrfs_release_path(path);
435
436 nrbits = block_group->length >> block_group->fs_info->sectorsize_bits;
437 start_bit = find_next_bit_le(bitmap, nrbits, 0);
438
439 while (start_bit < nrbits) {
440 end_bit = find_next_zero_bit_le(bitmap, nrbits, start_bit);
441 ASSERT(start_bit < end_bit);
442
443 key.objectid = start + start_bit * block_group->fs_info->sectorsize;
444 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
445 key.offset = (end_bit - start_bit) * block_group->fs_info->sectorsize;
446
447 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
448 if (ret)
449 goto out;
450 btrfs_release_path(path);
451
452 extent_count++;
453
454 start_bit = find_next_bit_le(bitmap, nrbits, end_bit);
455 }
456
457 if (extent_count != expected_extent_count) {
458 btrfs_err(fs_info,
459 "incorrect extent count for %llu; counted %u, expected %u",
460 block_group->start, extent_count,
461 expected_extent_count);
462 ASSERT(0);
463 ret = -EIO;
464 goto out;
465 }
466
467 ret = 0;
468out:
469 kvfree(bitmap);
470 if (ret)
471 btrfs_abort_transaction(trans, ret);
472 return ret;
473}
474
475static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
476 struct btrfs_block_group *block_group,
477 struct btrfs_path *path,
478 int new_extents)
479{
480 struct btrfs_free_space_info *info;
481 u32 flags;
482 u32 extent_count;
483 int ret = 0;
484
485 if (new_extents == 0)
486 return 0;
487
488 info = search_free_space_info(trans, block_group, path, 1);
489 if (IS_ERR(info)) {
490 ret = PTR_ERR(info);
491 goto out;
492 }
493 flags = btrfs_free_space_flags(path->nodes[0], info);
494 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
495
496 extent_count += new_extents;
497 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
498 btrfs_mark_buffer_dirty(trans, path->nodes[0]);
499 btrfs_release_path(path);
500
501 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
502 extent_count > block_group->bitmap_high_thresh) {
503 ret = convert_free_space_to_bitmaps(trans, block_group, path);
504 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
505 extent_count < block_group->bitmap_low_thresh) {
506 ret = convert_free_space_to_extents(trans, block_group, path);
507 }
508
509out:
510 return ret;
511}
512
513EXPORT_FOR_TESTS
514int free_space_test_bit(struct btrfs_block_group *block_group,
515 struct btrfs_path *path, u64 offset)
516{
517 struct extent_buffer *leaf;
518 struct btrfs_key key;
519 u64 found_start, found_end;
520 unsigned long ptr, i;
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(offset >= found_start && offset < found_end);
529
530 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
531 i = div_u64(offset - found_start,
532 block_group->fs_info->sectorsize);
533 return !!extent_buffer_test_bit(leaf, ptr, i);
534}
535
536static void free_space_set_bits(struct btrfs_trans_handle *trans,
537 struct btrfs_block_group *block_group,
538 struct btrfs_path *path, u64 *start, u64 *size,
539 int bit)
540{
541 struct btrfs_fs_info *fs_info = block_group->fs_info;
542 struct extent_buffer *leaf;
543 struct btrfs_key key;
544 u64 end = *start + *size;
545 u64 found_start, found_end;
546 unsigned long ptr, first, last;
547
548 leaf = path->nodes[0];
549 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
550 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
551
552 found_start = key.objectid;
553 found_end = key.objectid + key.offset;
554 ASSERT(*start >= found_start && *start < found_end);
555 ASSERT(end > found_start);
556
557 if (end > found_end)
558 end = found_end;
559
560 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
561 first = (*start - found_start) >> fs_info->sectorsize_bits;
562 last = (end - found_start) >> fs_info->sectorsize_bits;
563 if (bit)
564 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
565 else
566 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
567 btrfs_mark_buffer_dirty(trans, leaf);
568
569 *size -= end - *start;
570 *start = end;
571}
572
573/*
574 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
575 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
576 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
577 * looking for.
578 */
579static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
580 struct btrfs_root *root, struct btrfs_path *p)
581{
582 struct btrfs_key key;
583
584 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
585 p->slots[0]++;
586 return 0;
587 }
588
589 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
590 btrfs_release_path(p);
591
592 key.objectid += key.offset;
593 key.type = (u8)-1;
594 key.offset = (u64)-1;
595
596 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
597}
598
599/*
600 * If remove is 1, then we are removing free space, thus clearing bits in the
601 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
602 * the bitmap.
603 */
604static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
605 struct btrfs_block_group *block_group,
606 struct btrfs_path *path,
607 u64 start, u64 size, int remove)
608{
609 struct btrfs_root *root = btrfs_free_space_root(block_group);
610 struct btrfs_key key;
611 u64 end = start + size;
612 u64 cur_start, cur_size;
613 int prev_bit, next_bit;
614 int new_extents;
615 int ret;
616
617 /*
618 * Read the bit for the block immediately before the extent of space if
619 * that block is within the block group.
620 */
621 if (start > block_group->start) {
622 u64 prev_block = start - block_group->fs_info->sectorsize;
623
624 key.objectid = prev_block;
625 key.type = (u8)-1;
626 key.offset = (u64)-1;
627
628 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
629 if (ret)
630 goto out;
631
632 prev_bit = free_space_test_bit(block_group, path, prev_block);
633
634 /* The previous block may have been in the previous bitmap. */
635 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
636 if (start >= key.objectid + key.offset) {
637 ret = free_space_next_bitmap(trans, root, path);
638 if (ret)
639 goto out;
640 }
641 } else {
642 key.objectid = start;
643 key.type = (u8)-1;
644 key.offset = (u64)-1;
645
646 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
647 if (ret)
648 goto out;
649
650 prev_bit = -1;
651 }
652
653 /*
654 * Iterate over all of the bitmaps overlapped by the extent of space,
655 * clearing/setting bits as required.
656 */
657 cur_start = start;
658 cur_size = size;
659 while (1) {
660 free_space_set_bits(trans, block_group, path, &cur_start, &cur_size,
661 !remove);
662 if (cur_size == 0)
663 break;
664 ret = free_space_next_bitmap(trans, root, path);
665 if (ret)
666 goto out;
667 }
668
669 /*
670 * Read the bit for the block immediately after the extent of space if
671 * that block is within the block group.
672 */
673 if (end < block_group->start + block_group->length) {
674 /* The next block may be in the next bitmap. */
675 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
676 if (end >= key.objectid + key.offset) {
677 ret = free_space_next_bitmap(trans, root, path);
678 if (ret)
679 goto out;
680 }
681
682 next_bit = free_space_test_bit(block_group, path, end);
683 } else {
684 next_bit = -1;
685 }
686
687 if (remove) {
688 new_extents = -1;
689 if (prev_bit == 1) {
690 /* Leftover on the left. */
691 new_extents++;
692 }
693 if (next_bit == 1) {
694 /* Leftover on the right. */
695 new_extents++;
696 }
697 } else {
698 new_extents = 1;
699 if (prev_bit == 1) {
700 /* Merging with neighbor on the left. */
701 new_extents--;
702 }
703 if (next_bit == 1) {
704 /* Merging with neighbor on the right. */
705 new_extents--;
706 }
707 }
708
709 btrfs_release_path(path);
710 ret = update_free_space_extent_count(trans, block_group, path,
711 new_extents);
712
713out:
714 return ret;
715}
716
717static int remove_free_space_extent(struct btrfs_trans_handle *trans,
718 struct btrfs_block_group *block_group,
719 struct btrfs_path *path,
720 u64 start, u64 size)
721{
722 struct btrfs_root *root = btrfs_free_space_root(block_group);
723 struct btrfs_key key;
724 u64 found_start, found_end;
725 u64 end = start + size;
726 int new_extents = -1;
727 int ret;
728
729 key.objectid = start;
730 key.type = (u8)-1;
731 key.offset = (u64)-1;
732
733 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
734 if (ret)
735 goto out;
736
737 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
738
739 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
740
741 found_start = key.objectid;
742 found_end = key.objectid + key.offset;
743 ASSERT(start >= found_start && end <= found_end);
744
745 /*
746 * Okay, now that we've found the free space extent which contains the
747 * free space that we are removing, there are four cases:
748 *
749 * 1. We're using the whole extent: delete the key we found and
750 * decrement the free space extent count.
751 * 2. We are using part of the extent starting at the beginning: delete
752 * the key we found and insert a new key representing the leftover at
753 * the end. There is no net change in the number of extents.
754 * 3. We are using part of the extent ending at the end: delete the key
755 * we found and insert a new key representing the leftover at the
756 * beginning. There is no net change in the number of extents.
757 * 4. We are using part of the extent in the middle: delete the key we
758 * found and insert two new keys representing the leftovers on each
759 * side. Where we used to have one extent, we now have two, so increment
760 * the extent count. We may need to convert the block group to bitmaps
761 * as a result.
762 */
763
764 /* Delete the existing key (cases 1-4). */
765 ret = btrfs_del_item(trans, root, path);
766 if (ret)
767 goto out;
768
769 /* Add a key for leftovers at the beginning (cases 3 and 4). */
770 if (start > found_start) {
771 key.objectid = found_start;
772 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
773 key.offset = start - found_start;
774
775 btrfs_release_path(path);
776 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
777 if (ret)
778 goto out;
779 new_extents++;
780 }
781
782 /* Add a key for leftovers at the end (cases 2 and 4). */
783 if (end < found_end) {
784 key.objectid = end;
785 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
786 key.offset = found_end - end;
787
788 btrfs_release_path(path);
789 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
790 if (ret)
791 goto out;
792 new_extents++;
793 }
794
795 btrfs_release_path(path);
796 ret = update_free_space_extent_count(trans, block_group, path,
797 new_extents);
798
799out:
800 return ret;
801}
802
803EXPORT_FOR_TESTS
804int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
805 struct btrfs_block_group *block_group,
806 struct btrfs_path *path, u64 start, u64 size)
807{
808 struct btrfs_free_space_info *info;
809 u32 flags;
810 int ret;
811
812 if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) {
813 ret = __add_block_group_free_space(trans, block_group, path);
814 if (ret)
815 return ret;
816 }
817
818 info = search_free_space_info(NULL, block_group, path, 0);
819 if (IS_ERR(info))
820 return PTR_ERR(info);
821 flags = btrfs_free_space_flags(path->nodes[0], info);
822 btrfs_release_path(path);
823
824 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
825 return modify_free_space_bitmap(trans, block_group, path,
826 start, size, 1);
827 } else {
828 return remove_free_space_extent(trans, block_group, path,
829 start, size);
830 }
831}
832
833int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
834 u64 start, u64 size)
835{
836 struct btrfs_block_group *block_group;
837 struct btrfs_path *path;
838 int ret;
839
840 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
841 return 0;
842
843 path = btrfs_alloc_path();
844 if (!path) {
845 ret = -ENOMEM;
846 goto out;
847 }
848
849 block_group = btrfs_lookup_block_group(trans->fs_info, start);
850 if (!block_group) {
851 ASSERT(0);
852 ret = -ENOENT;
853 goto out;
854 }
855
856 mutex_lock(&block_group->free_space_lock);
857 ret = __remove_from_free_space_tree(trans, block_group, path, start,
858 size);
859 mutex_unlock(&block_group->free_space_lock);
860
861 btrfs_put_block_group(block_group);
862out:
863 btrfs_free_path(path);
864 if (ret)
865 btrfs_abort_transaction(trans, ret);
866 return ret;
867}
868
869static int add_free_space_extent(struct btrfs_trans_handle *trans,
870 struct btrfs_block_group *block_group,
871 struct btrfs_path *path,
872 u64 start, u64 size)
873{
874 struct btrfs_root *root = btrfs_free_space_root(block_group);
875 struct btrfs_key key, new_key;
876 u64 found_start, found_end;
877 u64 end = start + size;
878 int new_extents = 1;
879 int ret;
880
881 /*
882 * We are adding a new extent of free space, but we need to merge
883 * extents. There are four cases here:
884 *
885 * 1. The new extent does not have any immediate neighbors to merge
886 * with: add the new key and increment the free space extent count. We
887 * may need to convert the block group to bitmaps as a result.
888 * 2. The new extent has an immediate neighbor before it: remove the
889 * previous key and insert a new key combining both of them. There is no
890 * net change in the number of extents.
891 * 3. The new extent has an immediate neighbor after it: remove the next
892 * key and insert a new key combining both of them. There is no net
893 * change in the number of extents.
894 * 4. The new extent has immediate neighbors on both sides: remove both
895 * of the keys and insert a new key combining all of them. Where we used
896 * to have two extents, we now have one, so decrement the extent count.
897 */
898
899 new_key.objectid = start;
900 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
901 new_key.offset = size;
902
903 /* Search for a neighbor on the left. */
904 if (start == block_group->start)
905 goto right;
906 key.objectid = start - 1;
907 key.type = (u8)-1;
908 key.offset = (u64)-1;
909
910 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
911 if (ret)
912 goto out;
913
914 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
915
916 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
917 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
918 btrfs_release_path(path);
919 goto right;
920 }
921
922 found_start = key.objectid;
923 found_end = key.objectid + key.offset;
924 ASSERT(found_start >= block_group->start &&
925 found_end > block_group->start);
926 ASSERT(found_start < start && found_end <= start);
927
928 /*
929 * Delete the neighbor on the left and absorb it into the new key (cases
930 * 2 and 4).
931 */
932 if (found_end == start) {
933 ret = btrfs_del_item(trans, root, path);
934 if (ret)
935 goto out;
936 new_key.objectid = found_start;
937 new_key.offset += key.offset;
938 new_extents--;
939 }
940 btrfs_release_path(path);
941
942right:
943 /* Search for a neighbor on the right. */
944 if (end == block_group->start + block_group->length)
945 goto insert;
946 key.objectid = end;
947 key.type = (u8)-1;
948 key.offset = (u64)-1;
949
950 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
951 if (ret)
952 goto out;
953
954 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
955
956 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
957 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
958 btrfs_release_path(path);
959 goto insert;
960 }
961
962 found_start = key.objectid;
963 found_end = key.objectid + key.offset;
964 ASSERT(found_start >= block_group->start &&
965 found_end > block_group->start);
966 ASSERT((found_start < start && found_end <= start) ||
967 (found_start >= end && found_end > end));
968
969 /*
970 * Delete the neighbor on the right and absorb it into the new key
971 * (cases 3 and 4).
972 */
973 if (found_start == end) {
974 ret = btrfs_del_item(trans, root, path);
975 if (ret)
976 goto out;
977 new_key.offset += key.offset;
978 new_extents--;
979 }
980 btrfs_release_path(path);
981
982insert:
983 /* Insert the new key (cases 1-4). */
984 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
985 if (ret)
986 goto out;
987
988 btrfs_release_path(path);
989 ret = update_free_space_extent_count(trans, block_group, path,
990 new_extents);
991
992out:
993 return ret;
994}
995
996EXPORT_FOR_TESTS
997int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
998 struct btrfs_block_group *block_group,
999 struct btrfs_path *path, u64 start, u64 size)
1000{
1001 struct btrfs_free_space_info *info;
1002 u32 flags;
1003 int ret;
1004
1005 if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) {
1006 ret = __add_block_group_free_space(trans, block_group, path);
1007 if (ret)
1008 return ret;
1009 }
1010
1011 info = search_free_space_info(NULL, block_group, path, 0);
1012 if (IS_ERR(info))
1013 return PTR_ERR(info);
1014 flags = btrfs_free_space_flags(path->nodes[0], info);
1015 btrfs_release_path(path);
1016
1017 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
1018 return modify_free_space_bitmap(trans, block_group, path,
1019 start, size, 0);
1020 } else {
1021 return add_free_space_extent(trans, block_group, path, start,
1022 size);
1023 }
1024}
1025
1026int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1027 u64 start, u64 size)
1028{
1029 struct btrfs_block_group *block_group;
1030 struct btrfs_path *path;
1031 int ret;
1032
1033 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1034 return 0;
1035
1036 path = btrfs_alloc_path();
1037 if (!path) {
1038 ret = -ENOMEM;
1039 goto out;
1040 }
1041
1042 block_group = btrfs_lookup_block_group(trans->fs_info, start);
1043 if (!block_group) {
1044 ASSERT(0);
1045 ret = -ENOENT;
1046 goto out;
1047 }
1048
1049 mutex_lock(&block_group->free_space_lock);
1050 ret = __add_to_free_space_tree(trans, block_group, path, start, size);
1051 mutex_unlock(&block_group->free_space_lock);
1052
1053 btrfs_put_block_group(block_group);
1054out:
1055 btrfs_free_path(path);
1056 if (ret)
1057 btrfs_abort_transaction(trans, ret);
1058 return ret;
1059}
1060
1061/*
1062 * Populate the free space tree by walking the extent tree. Operations on the
1063 * extent tree that happen as a result of writes to the free space tree will go
1064 * through the normal add/remove hooks.
1065 */
1066static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1067 struct btrfs_block_group *block_group)
1068{
1069 struct btrfs_root *extent_root;
1070 struct btrfs_path *path, *path2;
1071 struct btrfs_key key;
1072 u64 start, end;
1073 int ret;
1074
1075 path = btrfs_alloc_path();
1076 if (!path)
1077 return -ENOMEM;
1078 path->reada = READA_FORWARD;
1079
1080 path2 = btrfs_alloc_path();
1081 if (!path2) {
1082 btrfs_free_path(path);
1083 return -ENOMEM;
1084 }
1085
1086 ret = add_new_free_space_info(trans, block_group, path2);
1087 if (ret)
1088 goto out;
1089
1090 mutex_lock(&block_group->free_space_lock);
1091
1092 /*
1093 * Iterate through all of the extent and metadata items in this block
1094 * group, adding the free space between them and the free space at the
1095 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1096 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1097 * contained in.
1098 */
1099 key.objectid = block_group->start;
1100 key.type = BTRFS_EXTENT_ITEM_KEY;
1101 key.offset = 0;
1102
1103 extent_root = btrfs_extent_root(trans->fs_info, key.objectid);
1104 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1105 if (ret < 0)
1106 goto out_locked;
1107 ASSERT(ret == 0);
1108
1109 start = block_group->start;
1110 end = block_group->start + block_group->length;
1111 while (1) {
1112 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1113
1114 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1115 key.type == BTRFS_METADATA_ITEM_KEY) {
1116 if (key.objectid >= end)
1117 break;
1118
1119 if (start < key.objectid) {
1120 ret = __add_to_free_space_tree(trans,
1121 block_group,
1122 path2, start,
1123 key.objectid -
1124 start);
1125 if (ret)
1126 goto out_locked;
1127 }
1128 start = key.objectid;
1129 if (key.type == BTRFS_METADATA_ITEM_KEY)
1130 start += trans->fs_info->nodesize;
1131 else
1132 start += key.offset;
1133 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1134 if (key.objectid != block_group->start)
1135 break;
1136 }
1137
1138 ret = btrfs_next_item(extent_root, path);
1139 if (ret < 0)
1140 goto out_locked;
1141 if (ret)
1142 break;
1143 }
1144 if (start < end) {
1145 ret = __add_to_free_space_tree(trans, block_group, path2,
1146 start, end - start);
1147 if (ret)
1148 goto out_locked;
1149 }
1150
1151 ret = 0;
1152out_locked:
1153 mutex_unlock(&block_group->free_space_lock);
1154out:
1155 btrfs_free_path(path2);
1156 btrfs_free_path(path);
1157 return ret;
1158}
1159
1160int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1161{
1162 struct btrfs_trans_handle *trans;
1163 struct btrfs_root *tree_root = fs_info->tree_root;
1164 struct btrfs_root *free_space_root;
1165 struct btrfs_block_group *block_group;
1166 struct rb_node *node;
1167 int ret;
1168
1169 trans = btrfs_start_transaction(tree_root, 0);
1170 if (IS_ERR(trans))
1171 return PTR_ERR(trans);
1172
1173 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1174 set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1175 free_space_root = btrfs_create_tree(trans,
1176 BTRFS_FREE_SPACE_TREE_OBJECTID);
1177 if (IS_ERR(free_space_root)) {
1178 ret = PTR_ERR(free_space_root);
1179 btrfs_abort_transaction(trans, ret);
1180 btrfs_end_transaction(trans);
1181 goto out_clear;
1182 }
1183 ret = btrfs_global_root_insert(free_space_root);
1184 if (ret) {
1185 btrfs_put_root(free_space_root);
1186 btrfs_abort_transaction(trans, ret);
1187 btrfs_end_transaction(trans);
1188 goto out_clear;
1189 }
1190
1191 node = rb_first_cached(&fs_info->block_group_cache_tree);
1192 while (node) {
1193 block_group = rb_entry(node, struct btrfs_block_group,
1194 cache_node);
1195 ret = populate_free_space_tree(trans, block_group);
1196 if (ret) {
1197 btrfs_abort_transaction(trans, ret);
1198 btrfs_end_transaction(trans);
1199 goto out_clear;
1200 }
1201 node = rb_next(node);
1202 }
1203
1204 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1205 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1206 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1207 ret = btrfs_commit_transaction(trans);
1208
1209 /*
1210 * Now that we've committed the transaction any reading of our commit
1211 * root will be safe, so we can cache from the free space tree now.
1212 */
1213 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1214 return ret;
1215
1216out_clear:
1217 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1218 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1219 return ret;
1220}
1221
1222static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1223 struct btrfs_root *root)
1224{
1225 struct btrfs_path *path;
1226 struct btrfs_key key;
1227 int nr;
1228 int ret;
1229
1230 path = btrfs_alloc_path();
1231 if (!path)
1232 return -ENOMEM;
1233
1234 key.objectid = 0;
1235 key.type = 0;
1236 key.offset = 0;
1237
1238 while (1) {
1239 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1240 if (ret < 0)
1241 goto out;
1242
1243 nr = btrfs_header_nritems(path->nodes[0]);
1244 if (!nr)
1245 break;
1246
1247 path->slots[0] = 0;
1248 ret = btrfs_del_items(trans, root, path, 0, nr);
1249 if (ret)
1250 goto out;
1251
1252 btrfs_release_path(path);
1253 }
1254
1255 ret = 0;
1256out:
1257 btrfs_free_path(path);
1258 return ret;
1259}
1260
1261int btrfs_delete_free_space_tree(struct btrfs_fs_info *fs_info)
1262{
1263 struct btrfs_trans_handle *trans;
1264 struct btrfs_root *tree_root = fs_info->tree_root;
1265 struct btrfs_key key = {
1266 .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID,
1267 .type = BTRFS_ROOT_ITEM_KEY,
1268 .offset = 0,
1269 };
1270 struct btrfs_root *free_space_root = btrfs_global_root(fs_info, &key);
1271 int ret;
1272
1273 trans = btrfs_start_transaction(tree_root, 0);
1274 if (IS_ERR(trans))
1275 return PTR_ERR(trans);
1276
1277 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1278 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1279
1280 ret = clear_free_space_tree(trans, free_space_root);
1281 if (ret) {
1282 btrfs_abort_transaction(trans, ret);
1283 btrfs_end_transaction(trans);
1284 return ret;
1285 }
1286
1287 ret = btrfs_del_root(trans, &free_space_root->root_key);
1288 if (ret) {
1289 btrfs_abort_transaction(trans, ret);
1290 btrfs_end_transaction(trans);
1291 return ret;
1292 }
1293
1294 btrfs_global_root_delete(free_space_root);
1295
1296 spin_lock(&fs_info->trans_lock);
1297 list_del(&free_space_root->dirty_list);
1298 spin_unlock(&fs_info->trans_lock);
1299
1300 btrfs_tree_lock(free_space_root->node);
1301 btrfs_clear_buffer_dirty(trans, free_space_root->node);
1302 btrfs_tree_unlock(free_space_root->node);
1303 ret = btrfs_free_tree_block(trans, btrfs_root_id(free_space_root),
1304 free_space_root->node, 0, 1);
1305 btrfs_put_root(free_space_root);
1306 if (ret < 0) {
1307 btrfs_abort_transaction(trans, ret);
1308 btrfs_end_transaction(trans);
1309 return ret;
1310 }
1311
1312 return btrfs_commit_transaction(trans);
1313}
1314
1315int btrfs_rebuild_free_space_tree(struct btrfs_fs_info *fs_info)
1316{
1317 struct btrfs_trans_handle *trans;
1318 struct btrfs_key key = {
1319 .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID,
1320 .type = BTRFS_ROOT_ITEM_KEY,
1321 .offset = 0,
1322 };
1323 struct btrfs_root *free_space_root = btrfs_global_root(fs_info, &key);
1324 struct rb_node *node;
1325 int ret;
1326
1327 trans = btrfs_start_transaction(free_space_root, 1);
1328 if (IS_ERR(trans))
1329 return PTR_ERR(trans);
1330
1331 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1332 set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1333
1334 ret = clear_free_space_tree(trans, free_space_root);
1335 if (ret) {
1336 btrfs_abort_transaction(trans, ret);
1337 btrfs_end_transaction(trans);
1338 return ret;
1339 }
1340
1341 node = rb_first_cached(&fs_info->block_group_cache_tree);
1342 while (node) {
1343 struct btrfs_block_group *block_group;
1344
1345 block_group = rb_entry(node, struct btrfs_block_group,
1346 cache_node);
1347 ret = populate_free_space_tree(trans, block_group);
1348 if (ret) {
1349 btrfs_abort_transaction(trans, ret);
1350 btrfs_end_transaction(trans);
1351 return ret;
1352 }
1353 node = rb_next(node);
1354 }
1355
1356 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1357 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1358 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1359
1360 ret = btrfs_commit_transaction(trans);
1361 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1362 return ret;
1363}
1364
1365static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
1366 struct btrfs_block_group *block_group,
1367 struct btrfs_path *path)
1368{
1369 int ret;
1370
1371 clear_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags);
1372
1373 ret = add_new_free_space_info(trans, block_group, path);
1374 if (ret)
1375 return ret;
1376
1377 return __add_to_free_space_tree(trans, block_group, path,
1378 block_group->start,
1379 block_group->length);
1380}
1381
1382int add_block_group_free_space(struct btrfs_trans_handle *trans,
1383 struct btrfs_block_group *block_group)
1384{
1385 struct btrfs_fs_info *fs_info = trans->fs_info;
1386 struct btrfs_path *path = NULL;
1387 int ret = 0;
1388
1389 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1390 return 0;
1391
1392 mutex_lock(&block_group->free_space_lock);
1393 if (!test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags))
1394 goto out;
1395
1396 path = btrfs_alloc_path();
1397 if (!path) {
1398 ret = -ENOMEM;
1399 goto out;
1400 }
1401
1402 ret = __add_block_group_free_space(trans, block_group, path);
1403
1404out:
1405 btrfs_free_path(path);
1406 mutex_unlock(&block_group->free_space_lock);
1407 if (ret)
1408 btrfs_abort_transaction(trans, ret);
1409 return ret;
1410}
1411
1412int remove_block_group_free_space(struct btrfs_trans_handle *trans,
1413 struct btrfs_block_group *block_group)
1414{
1415 struct btrfs_root *root = btrfs_free_space_root(block_group);
1416 struct btrfs_path *path;
1417 struct btrfs_key key, found_key;
1418 struct extent_buffer *leaf;
1419 u64 start, end;
1420 int done = 0, nr;
1421 int ret;
1422
1423 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1424 return 0;
1425
1426 if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) {
1427 /* We never added this block group to the free space tree. */
1428 return 0;
1429 }
1430
1431 path = btrfs_alloc_path();
1432 if (!path) {
1433 ret = -ENOMEM;
1434 goto out;
1435 }
1436
1437 start = block_group->start;
1438 end = block_group->start + block_group->length;
1439
1440 key.objectid = end - 1;
1441 key.type = (u8)-1;
1442 key.offset = (u64)-1;
1443
1444 while (!done) {
1445 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1446 if (ret)
1447 goto out;
1448
1449 leaf = path->nodes[0];
1450 nr = 0;
1451 path->slots[0]++;
1452 while (path->slots[0] > 0) {
1453 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1454
1455 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
1456 ASSERT(found_key.objectid == block_group->start);
1457 ASSERT(found_key.offset == block_group->length);
1458 done = 1;
1459 nr++;
1460 path->slots[0]--;
1461 break;
1462 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY ||
1463 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
1464 ASSERT(found_key.objectid >= start);
1465 ASSERT(found_key.objectid < end);
1466 ASSERT(found_key.objectid + found_key.offset <= end);
1467 nr++;
1468 path->slots[0]--;
1469 } else {
1470 ASSERT(0);
1471 }
1472 }
1473
1474 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1475 if (ret)
1476 goto out;
1477 btrfs_release_path(path);
1478 }
1479
1480 ret = 0;
1481out:
1482 btrfs_free_path(path);
1483 if (ret)
1484 btrfs_abort_transaction(trans, ret);
1485 return ret;
1486}
1487
1488static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1489 struct btrfs_path *path,
1490 u32 expected_extent_count)
1491{
1492 struct btrfs_block_group *block_group;
1493 struct btrfs_fs_info *fs_info;
1494 struct btrfs_root *root;
1495 struct btrfs_key key;
1496 int prev_bit = 0, bit;
1497 /* Initialize to silence GCC. */
1498 u64 extent_start = 0;
1499 u64 end, offset;
1500 u64 total_found = 0;
1501 u32 extent_count = 0;
1502 int ret;
1503
1504 block_group = caching_ctl->block_group;
1505 fs_info = block_group->fs_info;
1506 root = btrfs_free_space_root(block_group);
1507
1508 end = block_group->start + block_group->length;
1509
1510 while (1) {
1511 ret = btrfs_next_item(root, path);
1512 if (ret < 0)
1513 goto out;
1514 if (ret)
1515 break;
1516
1517 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1518
1519 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1520 break;
1521
1522 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1523 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1524
1525 offset = key.objectid;
1526 while (offset < key.objectid + key.offset) {
1527 bit = free_space_test_bit(block_group, path, offset);
1528 if (prev_bit == 0 && bit == 1) {
1529 extent_start = offset;
1530 } else if (prev_bit == 1 && bit == 0) {
1531 u64 space_added;
1532
1533 ret = btrfs_add_new_free_space(block_group,
1534 extent_start,
1535 offset,
1536 &space_added);
1537 if (ret)
1538 goto out;
1539 total_found += space_added;
1540 if (total_found > CACHING_CTL_WAKE_UP) {
1541 total_found = 0;
1542 wake_up(&caching_ctl->wait);
1543 }
1544 extent_count++;
1545 }
1546 prev_bit = bit;
1547 offset += fs_info->sectorsize;
1548 }
1549 }
1550 if (prev_bit == 1) {
1551 ret = btrfs_add_new_free_space(block_group, extent_start, end, NULL);
1552 if (ret)
1553 goto out;
1554 extent_count++;
1555 }
1556
1557 if (extent_count != expected_extent_count) {
1558 btrfs_err(fs_info,
1559 "incorrect extent count for %llu; counted %u, expected %u",
1560 block_group->start, extent_count,
1561 expected_extent_count);
1562 ASSERT(0);
1563 ret = -EIO;
1564 goto out;
1565 }
1566
1567 ret = 0;
1568out:
1569 return ret;
1570}
1571
1572static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1573 struct btrfs_path *path,
1574 u32 expected_extent_count)
1575{
1576 struct btrfs_block_group *block_group;
1577 struct btrfs_fs_info *fs_info;
1578 struct btrfs_root *root;
1579 struct btrfs_key key;
1580 u64 end;
1581 u64 total_found = 0;
1582 u32 extent_count = 0;
1583 int ret;
1584
1585 block_group = caching_ctl->block_group;
1586 fs_info = block_group->fs_info;
1587 root = btrfs_free_space_root(block_group);
1588
1589 end = block_group->start + block_group->length;
1590
1591 while (1) {
1592 u64 space_added;
1593
1594 ret = btrfs_next_item(root, path);
1595 if (ret < 0)
1596 goto out;
1597 if (ret)
1598 break;
1599
1600 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1601
1602 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1603 break;
1604
1605 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1606 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1607
1608 ret = btrfs_add_new_free_space(block_group, key.objectid,
1609 key.objectid + key.offset,
1610 &space_added);
1611 if (ret)
1612 goto out;
1613 total_found += space_added;
1614 if (total_found > CACHING_CTL_WAKE_UP) {
1615 total_found = 0;
1616 wake_up(&caching_ctl->wait);
1617 }
1618 extent_count++;
1619 }
1620
1621 if (extent_count != expected_extent_count) {
1622 btrfs_err(fs_info,
1623 "incorrect extent count for %llu; counted %u, expected %u",
1624 block_group->start, extent_count,
1625 expected_extent_count);
1626 ASSERT(0);
1627 ret = -EIO;
1628 goto out;
1629 }
1630
1631 ret = 0;
1632out:
1633 return ret;
1634}
1635
1636int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
1637{
1638 struct btrfs_block_group *block_group;
1639 struct btrfs_free_space_info *info;
1640 struct btrfs_path *path;
1641 u32 extent_count, flags;
1642 int ret;
1643
1644 block_group = caching_ctl->block_group;
1645
1646 path = btrfs_alloc_path();
1647 if (!path)
1648 return -ENOMEM;
1649
1650 /*
1651 * Just like caching_thread() doesn't want to deadlock on the extent
1652 * tree, we don't want to deadlock on the free space tree.
1653 */
1654 path->skip_locking = 1;
1655 path->search_commit_root = 1;
1656 path->reada = READA_FORWARD;
1657
1658 info = search_free_space_info(NULL, block_group, path, 0);
1659 if (IS_ERR(info)) {
1660 ret = PTR_ERR(info);
1661 goto out;
1662 }
1663 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
1664 flags = btrfs_free_space_flags(path->nodes[0], info);
1665
1666 /*
1667 * We left path pointing to the free space info item, so now
1668 * load_free_space_foo can just iterate through the free space tree from
1669 * there.
1670 */
1671 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS)
1672 ret = load_free_space_bitmaps(caching_ctl, path, extent_count);
1673 else
1674 ret = load_free_space_extents(caching_ctl, path, extent_count);
1675
1676out:
1677 btrfs_free_path(path);
1678 return ret;
1679}
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
15static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
16 struct btrfs_block_group_cache *block_group,
17 struct btrfs_path *path);
18
19void 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
47static int add_new_free_space_info(struct btrfs_trans_handle *trans,
48 struct btrfs_block_group_cache *block_group,
49 struct btrfs_path *path)
50{
51 struct btrfs_root *root = trans->fs_info->free_space_root;
52 struct btrfs_free_space_info *info;
53 struct btrfs_key key;
54 struct extent_buffer *leaf;
55 int ret;
56
57 key.objectid = block_group->key.objectid;
58 key.type = BTRFS_FREE_SPACE_INFO_KEY;
59 key.offset = block_group->key.offset;
60
61 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
62 if (ret)
63 goto out;
64
65 leaf = path->nodes[0];
66 info = btrfs_item_ptr(leaf, path->slots[0],
67 struct btrfs_free_space_info);
68 btrfs_set_free_space_extent_count(leaf, info, 0);
69 btrfs_set_free_space_flags(leaf, info, 0);
70 btrfs_mark_buffer_dirty(leaf);
71
72 ret = 0;
73out:
74 btrfs_release_path(path);
75 return ret;
76}
77
78EXPORT_FOR_TESTS
79struct btrfs_free_space_info *search_free_space_info(
80 struct btrfs_trans_handle *trans,
81 struct btrfs_block_group_cache *block_group,
82 struct btrfs_path *path, int cow)
83{
84 struct btrfs_fs_info *fs_info = block_group->fs_info;
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 */
111static 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
136static 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
141static unsigned long *alloc_bitmap(u32 bitmap_size)
142{
143 unsigned long *ret;
144 unsigned int nofs_flag;
145 u32 bitmap_rounded_size = round_up(bitmap_size, sizeof(unsigned long));
146
147 /*
148 * GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse
149 * into the filesystem as the free space bitmap can be modified in the
150 * critical section of a transaction commit.
151 *
152 * TODO: push the memalloc_nofs_{save,restore}() to the caller where we
153 * know that recursion is unsafe.
154 */
155 nofs_flag = memalloc_nofs_save();
156 ret = kvzalloc(bitmap_rounded_size, GFP_KERNEL);
157 memalloc_nofs_restore(nofs_flag);
158 return ret;
159}
160
161static void le_bitmap_set(unsigned long *map, unsigned int start, int len)
162{
163 u8 *p = ((u8 *)map) + BIT_BYTE(start);
164 const unsigned int size = start + len;
165 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
166 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
167
168 while (len - bits_to_set >= 0) {
169 *p |= mask_to_set;
170 len -= bits_to_set;
171 bits_to_set = BITS_PER_BYTE;
172 mask_to_set = ~0;
173 p++;
174 }
175 if (len) {
176 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
177 *p |= mask_to_set;
178 }
179}
180
181EXPORT_FOR_TESTS
182int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
183 struct btrfs_block_group_cache *block_group,
184 struct btrfs_path *path)
185{
186 struct btrfs_fs_info *fs_info = trans->fs_info;
187 struct btrfs_root *root = fs_info->free_space_root;
188 struct btrfs_free_space_info *info;
189 struct btrfs_key key, found_key;
190 struct extent_buffer *leaf;
191 unsigned long *bitmap;
192 char *bitmap_cursor;
193 u64 start, end;
194 u64 bitmap_range, i;
195 u32 bitmap_size, flags, expected_extent_count;
196 u32 extent_count = 0;
197 int done = 0, nr;
198 int ret;
199
200 bitmap_size = free_space_bitmap_size(block_group->key.offset,
201 fs_info->sectorsize);
202 bitmap = alloc_bitmap(bitmap_size);
203 if (!bitmap) {
204 ret = -ENOMEM;
205 goto out;
206 }
207
208 start = block_group->key.objectid;
209 end = block_group->key.objectid + block_group->key.offset;
210
211 key.objectid = end - 1;
212 key.type = (u8)-1;
213 key.offset = (u64)-1;
214
215 while (!done) {
216 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
217 if (ret)
218 goto out;
219
220 leaf = path->nodes[0];
221 nr = 0;
222 path->slots[0]++;
223 while (path->slots[0] > 0) {
224 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
225
226 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
227 ASSERT(found_key.objectid == block_group->key.objectid);
228 ASSERT(found_key.offset == block_group->key.offset);
229 done = 1;
230 break;
231 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
232 u64 first, last;
233
234 ASSERT(found_key.objectid >= start);
235 ASSERT(found_key.objectid < end);
236 ASSERT(found_key.objectid + found_key.offset <= end);
237
238 first = div_u64(found_key.objectid - start,
239 fs_info->sectorsize);
240 last = div_u64(found_key.objectid + found_key.offset - start,
241 fs_info->sectorsize);
242 le_bitmap_set(bitmap, first, last - first);
243
244 extent_count++;
245 nr++;
246 path->slots[0]--;
247 } else {
248 ASSERT(0);
249 }
250 }
251
252 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
253 if (ret)
254 goto out;
255 btrfs_release_path(path);
256 }
257
258 info = search_free_space_info(trans, block_group, path, 1);
259 if (IS_ERR(info)) {
260 ret = PTR_ERR(info);
261 goto out;
262 }
263 leaf = path->nodes[0];
264 flags = btrfs_free_space_flags(leaf, info);
265 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
266 btrfs_set_free_space_flags(leaf, info, flags);
267 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
268 btrfs_mark_buffer_dirty(leaf);
269 btrfs_release_path(path);
270
271 if (extent_count != expected_extent_count) {
272 btrfs_err(fs_info,
273 "incorrect extent count for %llu; counted %u, expected %u",
274 block_group->key.objectid, extent_count,
275 expected_extent_count);
276 ASSERT(0);
277 ret = -EIO;
278 goto out;
279 }
280
281 bitmap_cursor = (char *)bitmap;
282 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
283 i = start;
284 while (i < end) {
285 unsigned long ptr;
286 u64 extent_size;
287 u32 data_size;
288
289 extent_size = min(end - i, bitmap_range);
290 data_size = free_space_bitmap_size(extent_size,
291 fs_info->sectorsize);
292
293 key.objectid = i;
294 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
295 key.offset = extent_size;
296
297 ret = btrfs_insert_empty_item(trans, root, path, &key,
298 data_size);
299 if (ret)
300 goto out;
301
302 leaf = path->nodes[0];
303 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
304 write_extent_buffer(leaf, bitmap_cursor, ptr,
305 data_size);
306 btrfs_mark_buffer_dirty(leaf);
307 btrfs_release_path(path);
308
309 i += extent_size;
310 bitmap_cursor += data_size;
311 }
312
313 ret = 0;
314out:
315 kvfree(bitmap);
316 if (ret)
317 btrfs_abort_transaction(trans, ret);
318 return ret;
319}
320
321EXPORT_FOR_TESTS
322int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
323 struct btrfs_block_group_cache *block_group,
324 struct btrfs_path *path)
325{
326 struct btrfs_fs_info *fs_info = trans->fs_info;
327 struct btrfs_root *root = fs_info->free_space_root;
328 struct btrfs_free_space_info *info;
329 struct btrfs_key key, found_key;
330 struct extent_buffer *leaf;
331 unsigned long *bitmap;
332 u64 start, end;
333 u32 bitmap_size, flags, expected_extent_count;
334 unsigned long nrbits, start_bit, end_bit;
335 u32 extent_count = 0;
336 int done = 0, nr;
337 int ret;
338
339 bitmap_size = free_space_bitmap_size(block_group->key.offset,
340 fs_info->sectorsize);
341 bitmap = alloc_bitmap(bitmap_size);
342 if (!bitmap) {
343 ret = -ENOMEM;
344 goto out;
345 }
346
347 start = block_group->key.objectid;
348 end = block_group->key.objectid + block_group->key.offset;
349
350 key.objectid = end - 1;
351 key.type = (u8)-1;
352 key.offset = (u64)-1;
353
354 while (!done) {
355 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
356 if (ret)
357 goto out;
358
359 leaf = path->nodes[0];
360 nr = 0;
361 path->slots[0]++;
362 while (path->slots[0] > 0) {
363 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
364
365 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
366 ASSERT(found_key.objectid == block_group->key.objectid);
367 ASSERT(found_key.offset == block_group->key.offset);
368 done = 1;
369 break;
370 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
371 unsigned long ptr;
372 char *bitmap_cursor;
373 u32 bitmap_pos, data_size;
374
375 ASSERT(found_key.objectid >= start);
376 ASSERT(found_key.objectid < end);
377 ASSERT(found_key.objectid + found_key.offset <= end);
378
379 bitmap_pos = div_u64(found_key.objectid - start,
380 fs_info->sectorsize *
381 BITS_PER_BYTE);
382 bitmap_cursor = ((char *)bitmap) + bitmap_pos;
383 data_size = free_space_bitmap_size(found_key.offset,
384 fs_info->sectorsize);
385
386 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
387 read_extent_buffer(leaf, bitmap_cursor, ptr,
388 data_size);
389
390 nr++;
391 path->slots[0]--;
392 } else {
393 ASSERT(0);
394 }
395 }
396
397 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
398 if (ret)
399 goto out;
400 btrfs_release_path(path);
401 }
402
403 info = search_free_space_info(trans, block_group, path, 1);
404 if (IS_ERR(info)) {
405 ret = PTR_ERR(info);
406 goto out;
407 }
408 leaf = path->nodes[0];
409 flags = btrfs_free_space_flags(leaf, info);
410 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
411 btrfs_set_free_space_flags(leaf, info, flags);
412 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
413 btrfs_mark_buffer_dirty(leaf);
414 btrfs_release_path(path);
415
416 nrbits = div_u64(block_group->key.offset, block_group->fs_info->sectorsize);
417 start_bit = find_next_bit_le(bitmap, nrbits, 0);
418
419 while (start_bit < nrbits) {
420 end_bit = find_next_zero_bit_le(bitmap, nrbits, start_bit);
421 ASSERT(start_bit < end_bit);
422
423 key.objectid = start + start_bit * block_group->fs_info->sectorsize;
424 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
425 key.offset = (end_bit - start_bit) * block_group->fs_info->sectorsize;
426
427 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
428 if (ret)
429 goto out;
430 btrfs_release_path(path);
431
432 extent_count++;
433
434 start_bit = find_next_bit_le(bitmap, nrbits, end_bit);
435 }
436
437 if (extent_count != expected_extent_count) {
438 btrfs_err(fs_info,
439 "incorrect extent count for %llu; counted %u, expected %u",
440 block_group->key.objectid, extent_count,
441 expected_extent_count);
442 ASSERT(0);
443 ret = -EIO;
444 goto out;
445 }
446
447 ret = 0;
448out:
449 kvfree(bitmap);
450 if (ret)
451 btrfs_abort_transaction(trans, ret);
452 return ret;
453}
454
455static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
456 struct btrfs_block_group_cache *block_group,
457 struct btrfs_path *path,
458 int new_extents)
459{
460 struct btrfs_free_space_info *info;
461 u32 flags;
462 u32 extent_count;
463 int ret = 0;
464
465 if (new_extents == 0)
466 return 0;
467
468 info = search_free_space_info(trans, block_group, path, 1);
469 if (IS_ERR(info)) {
470 ret = PTR_ERR(info);
471 goto out;
472 }
473 flags = btrfs_free_space_flags(path->nodes[0], info);
474 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
475
476 extent_count += new_extents;
477 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
478 btrfs_mark_buffer_dirty(path->nodes[0]);
479 btrfs_release_path(path);
480
481 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
482 extent_count > block_group->bitmap_high_thresh) {
483 ret = convert_free_space_to_bitmaps(trans, block_group, path);
484 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
485 extent_count < block_group->bitmap_low_thresh) {
486 ret = convert_free_space_to_extents(trans, block_group, path);
487 }
488
489out:
490 return ret;
491}
492
493EXPORT_FOR_TESTS
494int free_space_test_bit(struct btrfs_block_group_cache *block_group,
495 struct btrfs_path *path, u64 offset)
496{
497 struct extent_buffer *leaf;
498 struct btrfs_key key;
499 u64 found_start, found_end;
500 unsigned long ptr, i;
501
502 leaf = path->nodes[0];
503 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
504 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
505
506 found_start = key.objectid;
507 found_end = key.objectid + key.offset;
508 ASSERT(offset >= found_start && offset < found_end);
509
510 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
511 i = div_u64(offset - found_start,
512 block_group->fs_info->sectorsize);
513 return !!extent_buffer_test_bit(leaf, ptr, i);
514}
515
516static void free_space_set_bits(struct btrfs_block_group_cache *block_group,
517 struct btrfs_path *path, u64 *start, u64 *size,
518 int bit)
519{
520 struct btrfs_fs_info *fs_info = block_group->fs_info;
521 struct extent_buffer *leaf;
522 struct btrfs_key key;
523 u64 end = *start + *size;
524 u64 found_start, found_end;
525 unsigned long ptr, first, last;
526
527 leaf = path->nodes[0];
528 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
529 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
530
531 found_start = key.objectid;
532 found_end = key.objectid + key.offset;
533 ASSERT(*start >= found_start && *start < found_end);
534 ASSERT(end > found_start);
535
536 if (end > found_end)
537 end = found_end;
538
539 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
540 first = div_u64(*start - found_start, fs_info->sectorsize);
541 last = div_u64(end - found_start, fs_info->sectorsize);
542 if (bit)
543 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
544 else
545 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
546 btrfs_mark_buffer_dirty(leaf);
547
548 *size -= end - *start;
549 *start = end;
550}
551
552/*
553 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
554 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
555 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
556 * looking for.
557 */
558static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
559 struct btrfs_root *root, struct btrfs_path *p)
560{
561 struct btrfs_key key;
562
563 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
564 p->slots[0]++;
565 return 0;
566 }
567
568 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
569 btrfs_release_path(p);
570
571 key.objectid += key.offset;
572 key.type = (u8)-1;
573 key.offset = (u64)-1;
574
575 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
576}
577
578/*
579 * If remove is 1, then we are removing free space, thus clearing bits in the
580 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
581 * the bitmap.
582 */
583static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
584 struct btrfs_block_group_cache *block_group,
585 struct btrfs_path *path,
586 u64 start, u64 size, int remove)
587{
588 struct btrfs_root *root = block_group->fs_info->free_space_root;
589 struct btrfs_key key;
590 u64 end = start + size;
591 u64 cur_start, cur_size;
592 int prev_bit, next_bit;
593 int new_extents;
594 int ret;
595
596 /*
597 * Read the bit for the block immediately before the extent of space if
598 * that block is within the block group.
599 */
600 if (start > block_group->key.objectid) {
601 u64 prev_block = start - block_group->fs_info->sectorsize;
602
603 key.objectid = prev_block;
604 key.type = (u8)-1;
605 key.offset = (u64)-1;
606
607 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
608 if (ret)
609 goto out;
610
611 prev_bit = free_space_test_bit(block_group, path, prev_block);
612
613 /* The previous block may have been in the previous bitmap. */
614 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
615 if (start >= key.objectid + key.offset) {
616 ret = free_space_next_bitmap(trans, root, path);
617 if (ret)
618 goto out;
619 }
620 } else {
621 key.objectid = start;
622 key.type = (u8)-1;
623 key.offset = (u64)-1;
624
625 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
626 if (ret)
627 goto out;
628
629 prev_bit = -1;
630 }
631
632 /*
633 * Iterate over all of the bitmaps overlapped by the extent of space,
634 * clearing/setting bits as required.
635 */
636 cur_start = start;
637 cur_size = size;
638 while (1) {
639 free_space_set_bits(block_group, path, &cur_start, &cur_size,
640 !remove);
641 if (cur_size == 0)
642 break;
643 ret = free_space_next_bitmap(trans, root, path);
644 if (ret)
645 goto out;
646 }
647
648 /*
649 * Read the bit for the block immediately after the extent of space if
650 * that block is within the block group.
651 */
652 if (end < block_group->key.objectid + block_group->key.offset) {
653 /* The next block may be in the next bitmap. */
654 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
655 if (end >= key.objectid + key.offset) {
656 ret = free_space_next_bitmap(trans, root, path);
657 if (ret)
658 goto out;
659 }
660
661 next_bit = free_space_test_bit(block_group, path, end);
662 } else {
663 next_bit = -1;
664 }
665
666 if (remove) {
667 new_extents = -1;
668 if (prev_bit == 1) {
669 /* Leftover on the left. */
670 new_extents++;
671 }
672 if (next_bit == 1) {
673 /* Leftover on the right. */
674 new_extents++;
675 }
676 } else {
677 new_extents = 1;
678 if (prev_bit == 1) {
679 /* Merging with neighbor on the left. */
680 new_extents--;
681 }
682 if (next_bit == 1) {
683 /* Merging with neighbor on the right. */
684 new_extents--;
685 }
686 }
687
688 btrfs_release_path(path);
689 ret = update_free_space_extent_count(trans, block_group, path,
690 new_extents);
691
692out:
693 return ret;
694}
695
696static int remove_free_space_extent(struct btrfs_trans_handle *trans,
697 struct btrfs_block_group_cache *block_group,
698 struct btrfs_path *path,
699 u64 start, u64 size)
700{
701 struct btrfs_root *root = trans->fs_info->free_space_root;
702 struct btrfs_key key;
703 u64 found_start, found_end;
704 u64 end = start + size;
705 int new_extents = -1;
706 int ret;
707
708 key.objectid = start;
709 key.type = (u8)-1;
710 key.offset = (u64)-1;
711
712 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
713 if (ret)
714 goto out;
715
716 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
717
718 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
719
720 found_start = key.objectid;
721 found_end = key.objectid + key.offset;
722 ASSERT(start >= found_start && end <= found_end);
723
724 /*
725 * Okay, now that we've found the free space extent which contains the
726 * free space that we are removing, there are four cases:
727 *
728 * 1. We're using the whole extent: delete the key we found and
729 * decrement the free space extent count.
730 * 2. We are using part of the extent starting at the beginning: delete
731 * the key we found and insert a new key representing the leftover at
732 * the end. There is no net change in the number of extents.
733 * 3. We are using part of the extent ending at the end: delete the key
734 * we found and insert a new key representing the leftover at the
735 * beginning. There is no net change in the number of extents.
736 * 4. We are using part of the extent in the middle: delete the key we
737 * found and insert two new keys representing the leftovers on each
738 * side. Where we used to have one extent, we now have two, so increment
739 * the extent count. We may need to convert the block group to bitmaps
740 * as a result.
741 */
742
743 /* Delete the existing key (cases 1-4). */
744 ret = btrfs_del_item(trans, root, path);
745 if (ret)
746 goto out;
747
748 /* Add a key for leftovers at the beginning (cases 3 and 4). */
749 if (start > found_start) {
750 key.objectid = found_start;
751 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
752 key.offset = start - found_start;
753
754 btrfs_release_path(path);
755 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
756 if (ret)
757 goto out;
758 new_extents++;
759 }
760
761 /* Add a key for leftovers at the end (cases 2 and 4). */
762 if (end < found_end) {
763 key.objectid = end;
764 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
765 key.offset = found_end - end;
766
767 btrfs_release_path(path);
768 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
769 if (ret)
770 goto out;
771 new_extents++;
772 }
773
774 btrfs_release_path(path);
775 ret = update_free_space_extent_count(trans, block_group, path,
776 new_extents);
777
778out:
779 return ret;
780}
781
782EXPORT_FOR_TESTS
783int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
784 struct btrfs_block_group_cache *block_group,
785 struct btrfs_path *path, u64 start, u64 size)
786{
787 struct btrfs_free_space_info *info;
788 u32 flags;
789 int ret;
790
791 if (block_group->needs_free_space) {
792 ret = __add_block_group_free_space(trans, block_group, path);
793 if (ret)
794 return ret;
795 }
796
797 info = search_free_space_info(NULL, block_group, path, 0);
798 if (IS_ERR(info))
799 return PTR_ERR(info);
800 flags = btrfs_free_space_flags(path->nodes[0], info);
801 btrfs_release_path(path);
802
803 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
804 return modify_free_space_bitmap(trans, block_group, path,
805 start, size, 1);
806 } else {
807 return remove_free_space_extent(trans, block_group, path,
808 start, size);
809 }
810}
811
812int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
813 u64 start, u64 size)
814{
815 struct btrfs_block_group_cache *block_group;
816 struct btrfs_path *path;
817 int ret;
818
819 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
820 return 0;
821
822 path = btrfs_alloc_path();
823 if (!path) {
824 ret = -ENOMEM;
825 goto out;
826 }
827
828 block_group = btrfs_lookup_block_group(trans->fs_info, start);
829 if (!block_group) {
830 ASSERT(0);
831 ret = -ENOENT;
832 goto out;
833 }
834
835 mutex_lock(&block_group->free_space_lock);
836 ret = __remove_from_free_space_tree(trans, block_group, path, start,
837 size);
838 mutex_unlock(&block_group->free_space_lock);
839
840 btrfs_put_block_group(block_group);
841out:
842 btrfs_free_path(path);
843 if (ret)
844 btrfs_abort_transaction(trans, ret);
845 return ret;
846}
847
848static int add_free_space_extent(struct btrfs_trans_handle *trans,
849 struct btrfs_block_group_cache *block_group,
850 struct btrfs_path *path,
851 u64 start, u64 size)
852{
853 struct btrfs_root *root = trans->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
921right:
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
961insert:
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, block_group, path,
969 new_extents);
970
971out:
972 return ret;
973}
974
975EXPORT_FOR_TESTS
976int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
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, block_group, path);
986 if (ret)
987 return ret;
988 }
989
990 info = search_free_space_info(NULL, block_group, path, 0);
991 if (IS_ERR(info))
992 return PTR_ERR(info);
993 flags = btrfs_free_space_flags(path->nodes[0], info);
994 btrfs_release_path(path);
995
996 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
997 return modify_free_space_bitmap(trans, block_group, path,
998 start, size, 0);
999 } else {
1000 return add_free_space_extent(trans, block_group, path, start,
1001 size);
1002 }
1003}
1004
1005int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1006 u64 start, u64 size)
1007{
1008 struct btrfs_block_group_cache *block_group;
1009 struct btrfs_path *path;
1010 int ret;
1011
1012 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1013 return 0;
1014
1015 path = btrfs_alloc_path();
1016 if (!path) {
1017 ret = -ENOMEM;
1018 goto out;
1019 }
1020
1021 block_group = btrfs_lookup_block_group(trans->fs_info, start);
1022 if (!block_group) {
1023 ASSERT(0);
1024 ret = -ENOENT;
1025 goto out;
1026 }
1027
1028 mutex_lock(&block_group->free_space_lock);
1029 ret = __add_to_free_space_tree(trans, block_group, path, start, size);
1030 mutex_unlock(&block_group->free_space_lock);
1031
1032 btrfs_put_block_group(block_group);
1033out:
1034 btrfs_free_path(path);
1035 if (ret)
1036 btrfs_abort_transaction(trans, ret);
1037 return ret;
1038}
1039
1040/*
1041 * Populate the free space tree by walking the extent tree. Operations on the
1042 * extent tree that happen as a result of writes to the free space tree will go
1043 * through the normal add/remove hooks.
1044 */
1045static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1046 struct btrfs_block_group_cache *block_group)
1047{
1048 struct btrfs_root *extent_root = trans->fs_info->extent_root;
1049 struct btrfs_path *path, *path2;
1050 struct btrfs_key key;
1051 u64 start, end;
1052 int ret;
1053
1054 path = btrfs_alloc_path();
1055 if (!path)
1056 return -ENOMEM;
1057 path->reada = READA_FORWARD;
1058
1059 path2 = btrfs_alloc_path();
1060 if (!path2) {
1061 btrfs_free_path(path);
1062 return -ENOMEM;
1063 }
1064
1065 ret = add_new_free_space_info(trans, block_group, path2);
1066 if (ret)
1067 goto out;
1068
1069 mutex_lock(&block_group->free_space_lock);
1070
1071 /*
1072 * Iterate through all of the extent and metadata items in this block
1073 * group, adding the free space between them and the free space at the
1074 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1075 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1076 * contained in.
1077 */
1078 key.objectid = block_group->key.objectid;
1079 key.type = BTRFS_EXTENT_ITEM_KEY;
1080 key.offset = 0;
1081
1082 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1083 if (ret < 0)
1084 goto out_locked;
1085 ASSERT(ret == 0);
1086
1087 start = block_group->key.objectid;
1088 end = block_group->key.objectid + block_group->key.offset;
1089 while (1) {
1090 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1091
1092 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1093 key.type == BTRFS_METADATA_ITEM_KEY) {
1094 if (key.objectid >= end)
1095 break;
1096
1097 if (start < key.objectid) {
1098 ret = __add_to_free_space_tree(trans,
1099 block_group,
1100 path2, start,
1101 key.objectid -
1102 start);
1103 if (ret)
1104 goto out_locked;
1105 }
1106 start = key.objectid;
1107 if (key.type == BTRFS_METADATA_ITEM_KEY)
1108 start += trans->fs_info->nodesize;
1109 else
1110 start += key.offset;
1111 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1112 if (key.objectid != block_group->key.objectid)
1113 break;
1114 }
1115
1116 ret = btrfs_next_item(extent_root, path);
1117 if (ret < 0)
1118 goto out_locked;
1119 if (ret)
1120 break;
1121 }
1122 if (start < end) {
1123 ret = __add_to_free_space_tree(trans, block_group, path2,
1124 start, end - start);
1125 if (ret)
1126 goto out_locked;
1127 }
1128
1129 ret = 0;
1130out_locked:
1131 mutex_unlock(&block_group->free_space_lock);
1132out:
1133 btrfs_free_path(path2);
1134 btrfs_free_path(path);
1135 return ret;
1136}
1137
1138int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1139{
1140 struct btrfs_trans_handle *trans;
1141 struct btrfs_root *tree_root = fs_info->tree_root;
1142 struct btrfs_root *free_space_root;
1143 struct btrfs_block_group_cache *block_group;
1144 struct rb_node *node;
1145 int ret;
1146
1147 trans = btrfs_start_transaction(tree_root, 0);
1148 if (IS_ERR(trans))
1149 return PTR_ERR(trans);
1150
1151 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1152 free_space_root = btrfs_create_tree(trans,
1153 BTRFS_FREE_SPACE_TREE_OBJECTID);
1154 if (IS_ERR(free_space_root)) {
1155 ret = PTR_ERR(free_space_root);
1156 goto abort;
1157 }
1158 fs_info->free_space_root = free_space_root;
1159
1160 node = rb_first(&fs_info->block_group_cache_tree);
1161 while (node) {
1162 block_group = rb_entry(node, struct btrfs_block_group_cache,
1163 cache_node);
1164 ret = populate_free_space_tree(trans, block_group);
1165 if (ret)
1166 goto abort;
1167 node = rb_next(node);
1168 }
1169
1170 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1171 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1172 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1173
1174 return btrfs_commit_transaction(trans);
1175
1176abort:
1177 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1178 btrfs_abort_transaction(trans, ret);
1179 btrfs_end_transaction(trans);
1180 return ret;
1181}
1182
1183static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1184 struct btrfs_root *root)
1185{
1186 struct btrfs_path *path;
1187 struct btrfs_key key;
1188 int nr;
1189 int ret;
1190
1191 path = btrfs_alloc_path();
1192 if (!path)
1193 return -ENOMEM;
1194
1195 path->leave_spinning = 1;
1196
1197 key.objectid = 0;
1198 key.type = 0;
1199 key.offset = 0;
1200
1201 while (1) {
1202 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1203 if (ret < 0)
1204 goto out;
1205
1206 nr = btrfs_header_nritems(path->nodes[0]);
1207 if (!nr)
1208 break;
1209
1210 path->slots[0] = 0;
1211 ret = btrfs_del_items(trans, root, path, 0, nr);
1212 if (ret)
1213 goto out;
1214
1215 btrfs_release_path(path);
1216 }
1217
1218 ret = 0;
1219out:
1220 btrfs_free_path(path);
1221 return ret;
1222}
1223
1224int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
1225{
1226 struct btrfs_trans_handle *trans;
1227 struct btrfs_root *tree_root = fs_info->tree_root;
1228 struct btrfs_root *free_space_root = fs_info->free_space_root;
1229 int ret;
1230
1231 trans = btrfs_start_transaction(tree_root, 0);
1232 if (IS_ERR(trans))
1233 return PTR_ERR(trans);
1234
1235 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1236 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1237 fs_info->free_space_root = NULL;
1238
1239 ret = clear_free_space_tree(trans, free_space_root);
1240 if (ret)
1241 goto abort;
1242
1243 ret = btrfs_del_root(trans, &free_space_root->root_key);
1244 if (ret)
1245 goto abort;
1246
1247 list_del(&free_space_root->dirty_list);
1248
1249 btrfs_tree_lock(free_space_root->node);
1250 btrfs_clean_tree_block(free_space_root->node);
1251 btrfs_tree_unlock(free_space_root->node);
1252 btrfs_free_tree_block(trans, free_space_root, free_space_root->node,
1253 0, 1);
1254
1255 free_extent_buffer(free_space_root->node);
1256 free_extent_buffer(free_space_root->commit_root);
1257 kfree(free_space_root);
1258
1259 return btrfs_commit_transaction(trans);
1260
1261abort:
1262 btrfs_abort_transaction(trans, ret);
1263 btrfs_end_transaction(trans);
1264 return ret;
1265}
1266
1267static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
1268 struct btrfs_block_group_cache *block_group,
1269 struct btrfs_path *path)
1270{
1271 int ret;
1272
1273 block_group->needs_free_space = 0;
1274
1275 ret = add_new_free_space_info(trans, block_group, path);
1276 if (ret)
1277 return ret;
1278
1279 return __add_to_free_space_tree(trans, block_group, path,
1280 block_group->key.objectid,
1281 block_group->key.offset);
1282}
1283
1284int add_block_group_free_space(struct btrfs_trans_handle *trans,
1285 struct btrfs_block_group_cache *block_group)
1286{
1287 struct btrfs_fs_info *fs_info = trans->fs_info;
1288 struct btrfs_path *path = NULL;
1289 int ret = 0;
1290
1291 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1292 return 0;
1293
1294 mutex_lock(&block_group->free_space_lock);
1295 if (!block_group->needs_free_space)
1296 goto out;
1297
1298 path = btrfs_alloc_path();
1299 if (!path) {
1300 ret = -ENOMEM;
1301 goto out;
1302 }
1303
1304 ret = __add_block_group_free_space(trans, block_group, path);
1305
1306out:
1307 btrfs_free_path(path);
1308 mutex_unlock(&block_group->free_space_lock);
1309 if (ret)
1310 btrfs_abort_transaction(trans, ret);
1311 return ret;
1312}
1313
1314int remove_block_group_free_space(struct btrfs_trans_handle *trans,
1315 struct btrfs_block_group_cache *block_group)
1316{
1317 struct btrfs_root *root = trans->fs_info->free_space_root;
1318 struct btrfs_path *path;
1319 struct btrfs_key key, found_key;
1320 struct extent_buffer *leaf;
1321 u64 start, end;
1322 int done = 0, nr;
1323 int ret;
1324
1325 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1326 return 0;
1327
1328 if (block_group->needs_free_space) {
1329 /* We never added this block group to the free space tree. */
1330 return 0;
1331 }
1332
1333 path = btrfs_alloc_path();
1334 if (!path) {
1335 ret = -ENOMEM;
1336 goto out;
1337 }
1338
1339 start = block_group->key.objectid;
1340 end = block_group->key.objectid + block_group->key.offset;
1341
1342 key.objectid = end - 1;
1343 key.type = (u8)-1;
1344 key.offset = (u64)-1;
1345
1346 while (!done) {
1347 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1348 if (ret)
1349 goto out;
1350
1351 leaf = path->nodes[0];
1352 nr = 0;
1353 path->slots[0]++;
1354 while (path->slots[0] > 0) {
1355 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1356
1357 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
1358 ASSERT(found_key.objectid == block_group->key.objectid);
1359 ASSERT(found_key.offset == block_group->key.offset);
1360 done = 1;
1361 nr++;
1362 path->slots[0]--;
1363 break;
1364 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY ||
1365 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
1366 ASSERT(found_key.objectid >= start);
1367 ASSERT(found_key.objectid < end);
1368 ASSERT(found_key.objectid + found_key.offset <= end);
1369 nr++;
1370 path->slots[0]--;
1371 } else {
1372 ASSERT(0);
1373 }
1374 }
1375
1376 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1377 if (ret)
1378 goto out;
1379 btrfs_release_path(path);
1380 }
1381
1382 ret = 0;
1383out:
1384 btrfs_free_path(path);
1385 if (ret)
1386 btrfs_abort_transaction(trans, ret);
1387 return ret;
1388}
1389
1390static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1391 struct btrfs_path *path,
1392 u32 expected_extent_count)
1393{
1394 struct btrfs_block_group_cache *block_group;
1395 struct btrfs_fs_info *fs_info;
1396 struct btrfs_root *root;
1397 struct btrfs_key key;
1398 int prev_bit = 0, bit;
1399 /* Initialize to silence GCC. */
1400 u64 extent_start = 0;
1401 u64 end, offset;
1402 u64 total_found = 0;
1403 u32 extent_count = 0;
1404 int ret;
1405
1406 block_group = caching_ctl->block_group;
1407 fs_info = block_group->fs_info;
1408 root = fs_info->free_space_root;
1409
1410 end = block_group->key.objectid + block_group->key.offset;
1411
1412 while (1) {
1413 ret = btrfs_next_item(root, path);
1414 if (ret < 0)
1415 goto out;
1416 if (ret)
1417 break;
1418
1419 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1420
1421 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1422 break;
1423
1424 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1425 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1426
1427 caching_ctl->progress = key.objectid;
1428
1429 offset = key.objectid;
1430 while (offset < key.objectid + key.offset) {
1431 bit = free_space_test_bit(block_group, path, offset);
1432 if (prev_bit == 0 && bit == 1) {
1433 extent_start = offset;
1434 } else if (prev_bit == 1 && bit == 0) {
1435 total_found += add_new_free_space(block_group,
1436 extent_start,
1437 offset);
1438 if (total_found > CACHING_CTL_WAKE_UP) {
1439 total_found = 0;
1440 wake_up(&caching_ctl->wait);
1441 }
1442 extent_count++;
1443 }
1444 prev_bit = bit;
1445 offset += fs_info->sectorsize;
1446 }
1447 }
1448 if (prev_bit == 1) {
1449 total_found += add_new_free_space(block_group, extent_start,
1450 end);
1451 extent_count++;
1452 }
1453
1454 if (extent_count != expected_extent_count) {
1455 btrfs_err(fs_info,
1456 "incorrect extent count for %llu; counted %u, expected %u",
1457 block_group->key.objectid, extent_count,
1458 expected_extent_count);
1459 ASSERT(0);
1460 ret = -EIO;
1461 goto out;
1462 }
1463
1464 caching_ctl->progress = (u64)-1;
1465
1466 ret = 0;
1467out:
1468 return ret;
1469}
1470
1471static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1472 struct btrfs_path *path,
1473 u32 expected_extent_count)
1474{
1475 struct btrfs_block_group_cache *block_group;
1476 struct btrfs_fs_info *fs_info;
1477 struct btrfs_root *root;
1478 struct btrfs_key key;
1479 u64 end;
1480 u64 total_found = 0;
1481 u32 extent_count = 0;
1482 int ret;
1483
1484 block_group = caching_ctl->block_group;
1485 fs_info = block_group->fs_info;
1486 root = fs_info->free_space_root;
1487
1488 end = block_group->key.objectid + block_group->key.offset;
1489
1490 while (1) {
1491 ret = btrfs_next_item(root, path);
1492 if (ret < 0)
1493 goto out;
1494 if (ret)
1495 break;
1496
1497 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1498
1499 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1500 break;
1501
1502 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1503 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1504
1505 caching_ctl->progress = key.objectid;
1506
1507 total_found += add_new_free_space(block_group, key.objectid,
1508 key.objectid + key.offset);
1509 if (total_found > CACHING_CTL_WAKE_UP) {
1510 total_found = 0;
1511 wake_up(&caching_ctl->wait);
1512 }
1513 extent_count++;
1514 }
1515
1516 if (extent_count != expected_extent_count) {
1517 btrfs_err(fs_info,
1518 "incorrect extent count for %llu; counted %u, expected %u",
1519 block_group->key.objectid, extent_count,
1520 expected_extent_count);
1521 ASSERT(0);
1522 ret = -EIO;
1523 goto out;
1524 }
1525
1526 caching_ctl->progress = (u64)-1;
1527
1528 ret = 0;
1529out:
1530 return ret;
1531}
1532
1533int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
1534{
1535 struct btrfs_block_group_cache *block_group;
1536 struct btrfs_free_space_info *info;
1537 struct btrfs_path *path;
1538 u32 extent_count, flags;
1539 int ret;
1540
1541 block_group = caching_ctl->block_group;
1542
1543 path = btrfs_alloc_path();
1544 if (!path)
1545 return -ENOMEM;
1546
1547 /*
1548 * Just like caching_thread() doesn't want to deadlock on the extent
1549 * tree, we don't want to deadlock on the free space tree.
1550 */
1551 path->skip_locking = 1;
1552 path->search_commit_root = 1;
1553 path->reada = READA_FORWARD;
1554
1555 info = search_free_space_info(NULL, block_group, path, 0);
1556 if (IS_ERR(info)) {
1557 ret = PTR_ERR(info);
1558 goto out;
1559 }
1560 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
1561 flags = btrfs_free_space_flags(path->nodes[0], info);
1562
1563 /*
1564 * We left path pointing to the free space info item, so now
1565 * load_free_space_foo can just iterate through the free space tree from
1566 * there.
1567 */
1568 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS)
1569 ret = load_free_space_bitmaps(caching_ctl, path, extent_count);
1570 else
1571 ret = load_free_space_extents(caching_ctl, path, extent_count);
1572
1573out:
1574 btrfs_free_path(path);
1575 return ret;
1576}