This repository has been archived by the owner on Mar 28, 2024. It is now read-only.
forked from LineageOS/android_kernel_xiaomi_sm6250
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathfree-space-tree.c
1603 lines (1363 loc) · 40.6 KB
/
free-space-tree.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Copyright (C) 2015 Facebook. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/kernel.h>
#include <linux/sched/mm.h>
#include "ctree.h"
#include "disk-io.h"
#include "locking.h"
#include "free-space-tree.h"
#include "transaction.h"
static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path);
void set_free_space_tree_thresholds(struct btrfs_block_group_cache *cache)
{
u32 bitmap_range;
size_t bitmap_size;
u64 num_bitmaps, total_bitmap_size;
/*
* We convert to bitmaps when the disk space required for using extents
* exceeds that required for using bitmaps.
*/
bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
num_bitmaps = div_u64(cache->key.offset + bitmap_range - 1,
bitmap_range);
bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
total_bitmap_size = num_bitmaps * bitmap_size;
cache->bitmap_high_thresh = div_u64(total_bitmap_size,
sizeof(struct btrfs_item));
/*
* We allow for a small buffer between the high threshold and low
* threshold to avoid thrashing back and forth between the two formats.
*/
if (cache->bitmap_high_thresh > 100)
cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
else
cache->bitmap_low_thresh = 0;
}
static int add_new_free_space_info(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path)
{
struct btrfs_root *root = fs_info->free_space_root;
struct btrfs_free_space_info *info;
struct btrfs_key key;
struct extent_buffer *leaf;
int ret;
key.objectid = block_group->key.objectid;
key.type = BTRFS_FREE_SPACE_INFO_KEY;
key.offset = block_group->key.offset;
ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
if (ret)
goto out;
leaf = path->nodes[0];
info = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_free_space_info);
btrfs_set_free_space_extent_count(leaf, info, 0);
btrfs_set_free_space_flags(leaf, info, 0);
btrfs_mark_buffer_dirty(leaf);
ret = 0;
out:
btrfs_release_path(path);
return ret;
}
struct btrfs_free_space_info *
search_free_space_info(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path, int cow)
{
struct btrfs_root *root = fs_info->free_space_root;
struct btrfs_key key;
int ret;
key.objectid = block_group->key.objectid;
key.type = BTRFS_FREE_SPACE_INFO_KEY;
key.offset = block_group->key.offset;
ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
if (ret < 0)
return ERR_PTR(ret);
if (ret != 0) {
btrfs_warn(fs_info, "missing free space info for %llu",
block_group->key.objectid);
ASSERT(0);
return ERR_PTR(-ENOENT);
}
return btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_free_space_info);
}
/*
* btrfs_search_slot() but we're looking for the greatest key less than the
* passed key.
*/
static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_key *key, struct btrfs_path *p,
int ins_len, int cow)
{
int ret;
ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
if (ret < 0)
return ret;
if (ret == 0) {
ASSERT(0);
return -EIO;
}
if (p->slots[0] == 0) {
ASSERT(0);
return -EIO;
}
p->slots[0]--;
return 0;
}
static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize)
{
return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
}
static u8 *alloc_bitmap(u32 bitmap_size)
{
u8 *ret;
unsigned int nofs_flag;
/*
* GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse
* into the filesystem as the free space bitmap can be modified in the
* critical section of a transaction commit.
*
* TODO: push the memalloc_nofs_{save,restore}() to the caller where we
* know that recursion is unsafe.
*/
nofs_flag = memalloc_nofs_save();
ret = kvzalloc(bitmap_size, GFP_KERNEL);
memalloc_nofs_restore(nofs_flag);
return ret;
}
int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path)
{
struct btrfs_root *root = fs_info->free_space_root;
struct btrfs_free_space_info *info;
struct btrfs_key key, found_key;
struct extent_buffer *leaf;
u8 *bitmap, *bitmap_cursor;
u64 start, end;
u64 bitmap_range, i;
u32 bitmap_size, flags, expected_extent_count;
u32 extent_count = 0;
int done = 0, nr;
int ret;
bitmap_size = free_space_bitmap_size(block_group->key.offset,
fs_info->sectorsize);
bitmap = alloc_bitmap(bitmap_size);
if (!bitmap) {
ret = -ENOMEM;
goto out;
}
start = block_group->key.objectid;
end = block_group->key.objectid + block_group->key.offset;
key.objectid = end - 1;
key.type = (u8)-1;
key.offset = (u64)-1;
while (!done) {
ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
if (ret)
goto out;
leaf = path->nodes[0];
nr = 0;
path->slots[0]++;
while (path->slots[0] > 0) {
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
ASSERT(found_key.objectid == block_group->key.objectid);
ASSERT(found_key.offset == block_group->key.offset);
done = 1;
break;
} else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
u64 first, last;
ASSERT(found_key.objectid >= start);
ASSERT(found_key.objectid < end);
ASSERT(found_key.objectid + found_key.offset <= end);
first = div_u64(found_key.objectid - start,
fs_info->sectorsize);
last = div_u64(found_key.objectid + found_key.offset - start,
fs_info->sectorsize);
le_bitmap_set(bitmap, first, last - first);
extent_count++;
nr++;
path->slots[0]--;
} else {
ASSERT(0);
}
}
ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
if (ret)
goto out;
btrfs_release_path(path);
}
info = search_free_space_info(trans, fs_info, block_group, path, 1);
if (IS_ERR(info)) {
ret = PTR_ERR(info);
goto out;
}
leaf = path->nodes[0];
flags = btrfs_free_space_flags(leaf, info);
flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
btrfs_set_free_space_flags(leaf, info, flags);
expected_extent_count = btrfs_free_space_extent_count(leaf, info);
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(path);
if (extent_count != expected_extent_count) {
btrfs_err(fs_info,
"incorrect extent count for %llu; counted %u, expected %u",
block_group->key.objectid, extent_count,
expected_extent_count);
ASSERT(0);
ret = -EIO;
goto out;
}
bitmap_cursor = bitmap;
bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
i = start;
while (i < end) {
unsigned long ptr;
u64 extent_size;
u32 data_size;
extent_size = min(end - i, bitmap_range);
data_size = free_space_bitmap_size(extent_size,
fs_info->sectorsize);
key.objectid = i;
key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
key.offset = extent_size;
ret = btrfs_insert_empty_item(trans, root, path, &key,
data_size);
if (ret)
goto out;
leaf = path->nodes[0];
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
write_extent_buffer(leaf, bitmap_cursor, ptr,
data_size);
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(path);
i += extent_size;
bitmap_cursor += data_size;
}
ret = 0;
out:
kvfree(bitmap);
if (ret)
btrfs_abort_transaction(trans, ret);
return ret;
}
int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path)
{
struct btrfs_root *root = fs_info->free_space_root;
struct btrfs_free_space_info *info;
struct btrfs_key key, found_key;
struct extent_buffer *leaf;
u8 *bitmap;
u64 start, end;
/* Initialize to silence GCC. */
u64 extent_start = 0;
u64 offset;
u32 bitmap_size, flags, expected_extent_count;
int prev_bit = 0, bit, bitnr;
u32 extent_count = 0;
int done = 0, nr;
int ret;
bitmap_size = free_space_bitmap_size(block_group->key.offset,
fs_info->sectorsize);
bitmap = alloc_bitmap(bitmap_size);
if (!bitmap) {
ret = -ENOMEM;
goto out;
}
start = block_group->key.objectid;
end = block_group->key.objectid + block_group->key.offset;
key.objectid = end - 1;
key.type = (u8)-1;
key.offset = (u64)-1;
while (!done) {
ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
if (ret)
goto out;
leaf = path->nodes[0];
nr = 0;
path->slots[0]++;
while (path->slots[0] > 0) {
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
ASSERT(found_key.objectid == block_group->key.objectid);
ASSERT(found_key.offset == block_group->key.offset);
done = 1;
break;
} else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
unsigned long ptr;
u8 *bitmap_cursor;
u32 bitmap_pos, data_size;
ASSERT(found_key.objectid >= start);
ASSERT(found_key.objectid < end);
ASSERT(found_key.objectid + found_key.offset <= end);
bitmap_pos = div_u64(found_key.objectid - start,
fs_info->sectorsize *
BITS_PER_BYTE);
bitmap_cursor = bitmap + bitmap_pos;
data_size = free_space_bitmap_size(found_key.offset,
fs_info->sectorsize);
ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
read_extent_buffer(leaf, bitmap_cursor, ptr,
data_size);
nr++;
path->slots[0]--;
} else {
ASSERT(0);
}
}
ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
if (ret)
goto out;
btrfs_release_path(path);
}
info = search_free_space_info(trans, fs_info, block_group, path, 1);
if (IS_ERR(info)) {
ret = PTR_ERR(info);
goto out;
}
leaf = path->nodes[0];
flags = btrfs_free_space_flags(leaf, info);
flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
btrfs_set_free_space_flags(leaf, info, flags);
expected_extent_count = btrfs_free_space_extent_count(leaf, info);
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(path);
offset = start;
bitnr = 0;
while (offset < end) {
bit = !!le_test_bit(bitnr, bitmap);
if (prev_bit == 0 && bit == 1) {
extent_start = offset;
} else if (prev_bit == 1 && bit == 0) {
key.objectid = extent_start;
key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
key.offset = offset - extent_start;
ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
if (ret)
goto out;
btrfs_release_path(path);
extent_count++;
}
prev_bit = bit;
offset += fs_info->sectorsize;
bitnr++;
}
if (prev_bit == 1) {
key.objectid = extent_start;
key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
key.offset = end - extent_start;
ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
if (ret)
goto out;
btrfs_release_path(path);
extent_count++;
}
if (extent_count != expected_extent_count) {
btrfs_err(fs_info,
"incorrect extent count for %llu; counted %u, expected %u",
block_group->key.objectid, extent_count,
expected_extent_count);
ASSERT(0);
ret = -EIO;
goto out;
}
ret = 0;
out:
kvfree(bitmap);
if (ret)
btrfs_abort_transaction(trans, ret);
return ret;
}
static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path,
int new_extents)
{
struct btrfs_free_space_info *info;
u32 flags;
u32 extent_count;
int ret = 0;
if (new_extents == 0)
return 0;
info = search_free_space_info(trans, fs_info, block_group, path, 1);
if (IS_ERR(info)) {
ret = PTR_ERR(info);
goto out;
}
flags = btrfs_free_space_flags(path->nodes[0], info);
extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
extent_count += new_extents;
btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(path);
if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
extent_count > block_group->bitmap_high_thresh) {
ret = convert_free_space_to_bitmaps(trans, fs_info, block_group,
path);
} else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
extent_count < block_group->bitmap_low_thresh) {
ret = convert_free_space_to_extents(trans, fs_info, block_group,
path);
}
out:
return ret;
}
int free_space_test_bit(struct btrfs_block_group_cache *block_group,
struct btrfs_path *path, u64 offset)
{
struct extent_buffer *leaf;
struct btrfs_key key;
u64 found_start, found_end;
unsigned long ptr, i;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
found_start = key.objectid;
found_end = key.objectid + key.offset;
ASSERT(offset >= found_start && offset < found_end);
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
i = div_u64(offset - found_start,
block_group->fs_info->sectorsize);
return !!extent_buffer_test_bit(leaf, ptr, i);
}
static void free_space_set_bits(struct btrfs_block_group_cache *block_group,
struct btrfs_path *path, u64 *start, u64 *size,
int bit)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct extent_buffer *leaf;
struct btrfs_key key;
u64 end = *start + *size;
u64 found_start, found_end;
unsigned long ptr, first, last;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
found_start = key.objectid;
found_end = key.objectid + key.offset;
ASSERT(*start >= found_start && *start < found_end);
ASSERT(end > found_start);
if (end > found_end)
end = found_end;
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
first = div_u64(*start - found_start, fs_info->sectorsize);
last = div_u64(end - found_start, fs_info->sectorsize);
if (bit)
extent_buffer_bitmap_set(leaf, ptr, first, last - first);
else
extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
btrfs_mark_buffer_dirty(leaf);
*size -= end - *start;
*start = end;
}
/*
* We can't use btrfs_next_item() in modify_free_space_bitmap() because
* btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
* tree walking in btrfs_next_leaf() anyways because we know exactly what we're
* looking for.
*/
static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *p)
{
struct btrfs_key key;
if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
p->slots[0]++;
return 0;
}
btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
btrfs_release_path(p);
key.objectid += key.offset;
key.type = (u8)-1;
key.offset = (u64)-1;
return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
}
/*
* If remove is 1, then we are removing free space, thus clearing bits in the
* bitmap. If remove is 0, then we are adding free space, thus setting bits in
* the bitmap.
*/
static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path,
u64 start, u64 size, int remove)
{
struct btrfs_root *root = fs_info->free_space_root;
struct btrfs_key key;
u64 end = start + size;
u64 cur_start, cur_size;
int prev_bit, next_bit;
int new_extents;
int ret;
/*
* Read the bit for the block immediately before the extent of space if
* that block is within the block group.
*/
if (start > block_group->key.objectid) {
u64 prev_block = start - block_group->fs_info->sectorsize;
key.objectid = prev_block;
key.type = (u8)-1;
key.offset = (u64)-1;
ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
if (ret)
goto out;
prev_bit = free_space_test_bit(block_group, path, prev_block);
/* The previous block may have been in the previous bitmap. */
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if (start >= key.objectid + key.offset) {
ret = free_space_next_bitmap(trans, root, path);
if (ret)
goto out;
}
} else {
key.objectid = start;
key.type = (u8)-1;
key.offset = (u64)-1;
ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
if (ret)
goto out;
prev_bit = -1;
}
/*
* Iterate over all of the bitmaps overlapped by the extent of space,
* clearing/setting bits as required.
*/
cur_start = start;
cur_size = size;
while (1) {
free_space_set_bits(block_group, path, &cur_start, &cur_size,
!remove);
if (cur_size == 0)
break;
ret = free_space_next_bitmap(trans, root, path);
if (ret)
goto out;
}
/*
* Read the bit for the block immediately after the extent of space if
* that block is within the block group.
*/
if (end < block_group->key.objectid + block_group->key.offset) {
/* The next block may be in the next bitmap. */
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if (end >= key.objectid + key.offset) {
ret = free_space_next_bitmap(trans, root, path);
if (ret)
goto out;
}
next_bit = free_space_test_bit(block_group, path, end);
} else {
next_bit = -1;
}
if (remove) {
new_extents = -1;
if (prev_bit == 1) {
/* Leftover on the left. */
new_extents++;
}
if (next_bit == 1) {
/* Leftover on the right. */
new_extents++;
}
} else {
new_extents = 1;
if (prev_bit == 1) {
/* Merging with neighbor on the left. */
new_extents--;
}
if (next_bit == 1) {
/* Merging with neighbor on the right. */
new_extents--;
}
}
btrfs_release_path(path);
ret = update_free_space_extent_count(trans, fs_info, block_group, path,
new_extents);
out:
return ret;
}
static int remove_free_space_extent(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path,
u64 start, u64 size)
{
struct btrfs_root *root = fs_info->free_space_root;
struct btrfs_key key;
u64 found_start, found_end;
u64 end = start + size;
int new_extents = -1;
int ret;
key.objectid = start;
key.type = (u8)-1;
key.offset = (u64)-1;
ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
if (ret)
goto out;
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
found_start = key.objectid;
found_end = key.objectid + key.offset;
ASSERT(start >= found_start && end <= found_end);
/*
* Okay, now that we've found the free space extent which contains the
* free space that we are removing, there are four cases:
*
* 1. We're using the whole extent: delete the key we found and
* decrement the free space extent count.
* 2. We are using part of the extent starting at the beginning: delete
* the key we found and insert a new key representing the leftover at
* the end. There is no net change in the number of extents.
* 3. We are using part of the extent ending at the end: delete the key
* we found and insert a new key representing the leftover at the
* beginning. There is no net change in the number of extents.
* 4. We are using part of the extent in the middle: delete the key we
* found and insert two new keys representing the leftovers on each
* side. Where we used to have one extent, we now have two, so increment
* the extent count. We may need to convert the block group to bitmaps
* as a result.
*/
/* Delete the existing key (cases 1-4). */
ret = btrfs_del_item(trans, root, path);
if (ret)
goto out;
/* Add a key for leftovers at the beginning (cases 3 and 4). */
if (start > found_start) {
key.objectid = found_start;
key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
key.offset = start - found_start;
btrfs_release_path(path);
ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
if (ret)
goto out;
new_extents++;
}
/* Add a key for leftovers at the end (cases 2 and 4). */
if (end < found_end) {
key.objectid = end;
key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
key.offset = found_end - end;
btrfs_release_path(path);
ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
if (ret)
goto out;
new_extents++;
}
btrfs_release_path(path);
ret = update_free_space_extent_count(trans, fs_info, block_group, path,
new_extents);
out:
return ret;
}
int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path, u64 start, u64 size)
{
struct btrfs_free_space_info *info;
u32 flags;
int ret;
if (block_group->needs_free_space) {
ret = __add_block_group_free_space(trans, fs_info, block_group,
path);
if (ret)
return ret;
}
info = search_free_space_info(NULL, fs_info, block_group, path, 0);
if (IS_ERR(info))
return PTR_ERR(info);
flags = btrfs_free_space_flags(path->nodes[0], info);
btrfs_release_path(path);
if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
return modify_free_space_bitmap(trans, fs_info, block_group,
path, start, size, 1);
} else {
return remove_free_space_extent(trans, fs_info, block_group,
path, start, size);
}
}
int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
u64 start, u64 size)
{
struct btrfs_block_group_cache *block_group;
struct btrfs_path *path;
int ret;
if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
return 0;
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
block_group = btrfs_lookup_block_group(fs_info, start);
if (!block_group) {
ASSERT(0);
ret = -ENOENT;
goto out;
}
mutex_lock(&block_group->free_space_lock);
ret = __remove_from_free_space_tree(trans, fs_info, block_group, path,
start, size);
mutex_unlock(&block_group->free_space_lock);
btrfs_put_block_group(block_group);
out:
btrfs_free_path(path);
if (ret)
btrfs_abort_transaction(trans, ret);
return ret;
}
static int add_free_space_extent(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path,
u64 start, u64 size)
{
struct btrfs_root *root = fs_info->free_space_root;
struct btrfs_key key, new_key;
u64 found_start, found_end;
u64 end = start + size;
int new_extents = 1;
int ret;
/*
* We are adding a new extent of free space, but we need to merge
* extents. There are four cases here:
*
* 1. The new extent does not have any immediate neighbors to merge
* with: add the new key and increment the free space extent count. We
* may need to convert the block group to bitmaps as a result.
* 2. The new extent has an immediate neighbor before it: remove the
* previous key and insert a new key combining both of them. There is no
* net change in the number of extents.
* 3. The new extent has an immediate neighbor after it: remove the next
* key and insert a new key combining both of them. There is no net
* change in the number of extents.
* 4. The new extent has immediate neighbors on both sides: remove both
* of the keys and insert a new key combining all of them. Where we used
* to have two extents, we now have one, so decrement the extent count.
*/
new_key.objectid = start;
new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
new_key.offset = size;
/* Search for a neighbor on the left. */
if (start == block_group->key.objectid)
goto right;
key.objectid = start - 1;
key.type = (u8)-1;
key.offset = (u64)-1;
ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
if (ret)
goto out;
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
btrfs_release_path(path);
goto right;
}
found_start = key.objectid;
found_end = key.objectid + key.offset;
ASSERT(found_start >= block_group->key.objectid &&
found_end > block_group->key.objectid);
ASSERT(found_start < start && found_end <= start);
/*
* Delete the neighbor on the left and absorb it into the new key (cases
* 2 and 4).
*/
if (found_end == start) {
ret = btrfs_del_item(trans, root, path);
if (ret)
goto out;
new_key.objectid = found_start;
new_key.offset += key.offset;
new_extents--;
}
btrfs_release_path(path);
right:
/* Search for a neighbor on the right. */
if (end == block_group->key.objectid + block_group->key.offset)
goto insert;
key.objectid = end;
key.type = (u8)-1;
key.offset = (u64)-1;
ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
if (ret)
goto out;
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
btrfs_release_path(path);
goto insert;
}
found_start = key.objectid;
found_end = key.objectid + key.offset;
ASSERT(found_start >= block_group->key.objectid &&
found_end > block_group->key.objectid);
ASSERT((found_start < start && found_end <= start) ||
(found_start >= end && found_end > end));
/*
* Delete the neighbor on the right and absorb it into the new key
* (cases 3 and 4).
*/
if (found_start == end) {
ret = btrfs_del_item(trans, root, path);
if (ret)
goto out;
new_key.offset += key.offset;
new_extents--;
}
btrfs_release_path(path);
insert:
/* Insert the new key (cases 1-4). */
ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
if (ret)
goto out;
btrfs_release_path(path);
ret = update_free_space_extent_count(trans, fs_info, block_group, path,
new_extents);
out:
return ret;
}
int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_block_group_cache *block_group,
struct btrfs_path *path, u64 start, u64 size)
{
struct btrfs_free_space_info *info;
u32 flags;
int ret;
if (block_group->needs_free_space) {
ret = __add_block_group_free_space(trans, fs_info, block_group,
path);
if (ret)