forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 1
/
bitmap.c
1571 lines (1293 loc) · 32.2 KB
/
bitmap.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
// SPDX-License-Identifier: GPL-2.0
/*
*
* Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
*
* This code builds two trees of free clusters extents.
* Trees are sorted by start of extent and by length of extent.
* NTFS_MAX_WND_EXTENTS defines the maximum number of elements in trees.
* In extreme case code reads on-disk bitmap to find free clusters.
*
*/
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include "ntfs.h"
#include "ntfs_fs.h"
/*
* Maximum number of extents in tree.
*/
#define NTFS_MAX_WND_EXTENTS (32u * 1024u)
struct rb_node_key {
struct rb_node node;
size_t key;
};
struct e_node {
struct rb_node_key start; /* Tree sorted by start. */
struct rb_node_key count; /* Tree sorted by len. */
};
static int wnd_rescan(struct wnd_bitmap *wnd);
static struct buffer_head *wnd_map(struct wnd_bitmap *wnd, size_t iw);
static bool wnd_is_free_hlp(struct wnd_bitmap *wnd, size_t bit, size_t bits);
static struct kmem_cache *ntfs_enode_cachep;
int __init ntfs3_init_bitmap(void)
{
ntfs_enode_cachep =
kmem_cache_create("ntfs3_enode_cache", sizeof(struct e_node), 0,
SLAB_RECLAIM_ACCOUNT, NULL);
return ntfs_enode_cachep ? 0 : -ENOMEM;
}
void ntfs3_exit_bitmap(void)
{
kmem_cache_destroy(ntfs_enode_cachep);
}
/*
* wnd_scan
*
* b_pos + b_len - biggest fragment.
* Scan range [wpos wbits) window @buf.
*
* Return: -1 if not found.
*/
static size_t wnd_scan(const void *buf, size_t wbit, u32 wpos, u32 wend,
size_t to_alloc, size_t *prev_tail, size_t *b_pos,
size_t *b_len)
{
while (wpos < wend) {
size_t free_len;
u32 free_bits, end;
u32 used = find_next_zero_bit_le(buf, wend, wpos);
if (used >= wend) {
if (*b_len < *prev_tail) {
*b_pos = wbit - *prev_tail;
*b_len = *prev_tail;
}
*prev_tail = 0;
return -1;
}
if (used > wpos) {
wpos = used;
if (*b_len < *prev_tail) {
*b_pos = wbit - *prev_tail;
*b_len = *prev_tail;
}
*prev_tail = 0;
}
/*
* Now we have a fragment [wpos, wend) staring with 0.
*/
end = wpos + to_alloc - *prev_tail;
free_bits = find_next_bit_le(buf, min(end, wend), wpos);
free_len = *prev_tail + free_bits - wpos;
if (*b_len < free_len) {
*b_pos = wbit + wpos - *prev_tail;
*b_len = free_len;
}
if (free_len >= to_alloc)
return wbit + wpos - *prev_tail;
if (free_bits >= wend) {
*prev_tail += free_bits - wpos;
return -1;
}
wpos = free_bits + 1;
*prev_tail = 0;
}
return -1;
}
/*
* wnd_close - Frees all resources.
*/
void wnd_close(struct wnd_bitmap *wnd)
{
struct rb_node *node, *next;
kfree(wnd->free_bits);
run_close(&wnd->run);
node = rb_first(&wnd->start_tree);
while (node) {
next = rb_next(node);
rb_erase(node, &wnd->start_tree);
kmem_cache_free(ntfs_enode_cachep,
rb_entry(node, struct e_node, start.node));
node = next;
}
}
static struct rb_node *rb_lookup(struct rb_root *root, size_t v)
{
struct rb_node **p = &root->rb_node;
struct rb_node *r = NULL;
while (*p) {
struct rb_node_key *k;
k = rb_entry(*p, struct rb_node_key, node);
if (v < k->key) {
p = &(*p)->rb_left;
} else if (v > k->key) {
r = &k->node;
p = &(*p)->rb_right;
} else {
return &k->node;
}
}
return r;
}
/*
* rb_insert_count - Helper function to insert special kind of 'count' tree.
*/
static inline bool rb_insert_count(struct rb_root *root, struct e_node *e)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
size_t e_ckey = e->count.key;
size_t e_skey = e->start.key;
while (*p) {
struct e_node *k =
rb_entry(parent = *p, struct e_node, count.node);
if (e_ckey > k->count.key) {
p = &(*p)->rb_left;
} else if (e_ckey < k->count.key) {
p = &(*p)->rb_right;
} else if (e_skey < k->start.key) {
p = &(*p)->rb_left;
} else if (e_skey > k->start.key) {
p = &(*p)->rb_right;
} else {
WARN_ON(1);
return false;
}
}
rb_link_node(&e->count.node, parent, p);
rb_insert_color(&e->count.node, root);
return true;
}
/*
* rb_insert_start - Helper function to insert special kind of 'count' tree.
*/
static inline bool rb_insert_start(struct rb_root *root, struct e_node *e)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
size_t e_skey = e->start.key;
while (*p) {
struct e_node *k;
parent = *p;
k = rb_entry(parent, struct e_node, start.node);
if (e_skey < k->start.key) {
p = &(*p)->rb_left;
} else if (e_skey > k->start.key) {
p = &(*p)->rb_right;
} else {
WARN_ON(1);
return false;
}
}
rb_link_node(&e->start.node, parent, p);
rb_insert_color(&e->start.node, root);
return true;
}
/*
* wnd_add_free_ext - Adds a new extent of free space.
* @build: 1 when building tree.
*/
static void wnd_add_free_ext(struct wnd_bitmap *wnd, size_t bit, size_t len,
bool build)
{
struct e_node *e, *e0 = NULL;
size_t ib, end_in = bit + len;
struct rb_node *n;
if (build) {
/* Use extent_min to filter too short extents. */
if (wnd->count >= NTFS_MAX_WND_EXTENTS &&
len <= wnd->extent_min) {
wnd->uptodated = -1;
return;
}
} else {
/* Try to find extent before 'bit'. */
n = rb_lookup(&wnd->start_tree, bit);
if (!n) {
n = rb_first(&wnd->start_tree);
} else {
e = rb_entry(n, struct e_node, start.node);
n = rb_next(n);
if (e->start.key + e->count.key == bit) {
/* Remove left. */
bit = e->start.key;
len += e->count.key;
rb_erase(&e->start.node, &wnd->start_tree);
rb_erase(&e->count.node, &wnd->count_tree);
wnd->count -= 1;
e0 = e;
}
}
while (n) {
size_t next_end;
e = rb_entry(n, struct e_node, start.node);
next_end = e->start.key + e->count.key;
if (e->start.key > end_in)
break;
/* Remove right. */
n = rb_next(n);
len += next_end - end_in;
end_in = next_end;
rb_erase(&e->start.node, &wnd->start_tree);
rb_erase(&e->count.node, &wnd->count_tree);
wnd->count -= 1;
if (!e0)
e0 = e;
else
kmem_cache_free(ntfs_enode_cachep, e);
}
if (wnd->uptodated != 1) {
/* Check bits before 'bit'. */
ib = wnd->zone_bit == wnd->zone_end ||
bit < wnd->zone_end
? 0
: wnd->zone_end;
while (bit > ib && wnd_is_free_hlp(wnd, bit - 1, 1)) {
bit -= 1;
len += 1;
}
/* Check bits after 'end_in'. */
ib = wnd->zone_bit == wnd->zone_end ||
end_in > wnd->zone_bit
? wnd->nbits
: wnd->zone_bit;
while (end_in < ib && wnd_is_free_hlp(wnd, end_in, 1)) {
end_in += 1;
len += 1;
}
}
}
/* Insert new fragment. */
if (wnd->count >= NTFS_MAX_WND_EXTENTS) {
if (e0)
kmem_cache_free(ntfs_enode_cachep, e0);
wnd->uptodated = -1;
/* Compare with smallest fragment. */
n = rb_last(&wnd->count_tree);
e = rb_entry(n, struct e_node, count.node);
if (len <= e->count.key)
goto out; /* Do not insert small fragments. */
if (build) {
struct e_node *e2;
n = rb_prev(n);
e2 = rb_entry(n, struct e_node, count.node);
/* Smallest fragment will be 'e2->count.key'. */
wnd->extent_min = e2->count.key;
}
/* Replace smallest fragment by new one. */
rb_erase(&e->start.node, &wnd->start_tree);
rb_erase(&e->count.node, &wnd->count_tree);
wnd->count -= 1;
} else {
e = e0 ? e0 : kmem_cache_alloc(ntfs_enode_cachep, GFP_ATOMIC);
if (!e) {
wnd->uptodated = -1;
goto out;
}
if (build && len <= wnd->extent_min)
wnd->extent_min = len;
}
e->start.key = bit;
e->count.key = len;
if (len > wnd->extent_max)
wnd->extent_max = len;
rb_insert_start(&wnd->start_tree, e);
rb_insert_count(&wnd->count_tree, e);
wnd->count += 1;
out:;
}
/*
* wnd_remove_free_ext - Remove a run from the cached free space.
*/
static void wnd_remove_free_ext(struct wnd_bitmap *wnd, size_t bit, size_t len)
{
struct rb_node *n, *n3;
struct e_node *e, *e3;
size_t end_in = bit + len;
size_t end3, end, new_key, new_len, max_new_len;
/* Try to find extent before 'bit'. */
n = rb_lookup(&wnd->start_tree, bit);
if (!n)
return;
e = rb_entry(n, struct e_node, start.node);
end = e->start.key + e->count.key;
new_key = new_len = 0;
len = e->count.key;
/* Range [bit,end_in) must be inside 'e' or outside 'e' and 'n'. */
if (e->start.key > bit)
;
else if (end_in <= end) {
/* Range [bit,end_in) inside 'e'. */
new_key = end_in;
new_len = end - end_in;
len = bit - e->start.key;
} else if (bit > end) {
bool bmax = false;
n3 = rb_next(n);
while (n3) {
e3 = rb_entry(n3, struct e_node, start.node);
if (e3->start.key >= end_in)
break;
if (e3->count.key == wnd->extent_max)
bmax = true;
end3 = e3->start.key + e3->count.key;
if (end3 > end_in) {
e3->start.key = end_in;
rb_erase(&e3->count.node, &wnd->count_tree);
e3->count.key = end3 - end_in;
rb_insert_count(&wnd->count_tree, e3);
break;
}
n3 = rb_next(n3);
rb_erase(&e3->start.node, &wnd->start_tree);
rb_erase(&e3->count.node, &wnd->count_tree);
wnd->count -= 1;
kmem_cache_free(ntfs_enode_cachep, e3);
}
if (!bmax)
return;
n3 = rb_first(&wnd->count_tree);
wnd->extent_max =
n3 ? rb_entry(n3, struct e_node, count.node)->count.key
: 0;
return;
}
if (e->count.key != wnd->extent_max) {
;
} else if (rb_prev(&e->count.node)) {
;
} else {
n3 = rb_next(&e->count.node);
max_new_len = max(len, new_len);
if (!n3) {
wnd->extent_max = max_new_len;
} else {
e3 = rb_entry(n3, struct e_node, count.node);
wnd->extent_max = max(e3->count.key, max_new_len);
}
}
if (!len) {
if (new_len) {
e->start.key = new_key;
rb_erase(&e->count.node, &wnd->count_tree);
e->count.key = new_len;
rb_insert_count(&wnd->count_tree, e);
} else {
rb_erase(&e->start.node, &wnd->start_tree);
rb_erase(&e->count.node, &wnd->count_tree);
wnd->count -= 1;
kmem_cache_free(ntfs_enode_cachep, e);
}
goto out;
}
rb_erase(&e->count.node, &wnd->count_tree);
e->count.key = len;
rb_insert_count(&wnd->count_tree, e);
if (!new_len)
goto out;
if (wnd->count >= NTFS_MAX_WND_EXTENTS) {
wnd->uptodated = -1;
/* Get minimal extent. */
e = rb_entry(rb_last(&wnd->count_tree), struct e_node,
count.node);
if (e->count.key > new_len)
goto out;
/* Replace minimum. */
rb_erase(&e->start.node, &wnd->start_tree);
rb_erase(&e->count.node, &wnd->count_tree);
wnd->count -= 1;
} else {
e = kmem_cache_alloc(ntfs_enode_cachep, GFP_ATOMIC);
if (!e)
wnd->uptodated = -1;
}
if (e) {
e->start.key = new_key;
e->count.key = new_len;
rb_insert_start(&wnd->start_tree, e);
rb_insert_count(&wnd->count_tree, e);
wnd->count += 1;
}
out:
if (!wnd->count && 1 != wnd->uptodated)
wnd_rescan(wnd);
}
/*
* wnd_rescan - Scan all bitmap. Used while initialization.
*/
static int wnd_rescan(struct wnd_bitmap *wnd)
{
int err = 0;
size_t prev_tail = 0;
struct super_block *sb = wnd->sb;
struct ntfs_sb_info *sbi = sb->s_fs_info;
u64 lbo, len = 0;
u32 blocksize = sb->s_blocksize;
u8 cluster_bits = sbi->cluster_bits;
u32 wbits = 8 * sb->s_blocksize;
u32 used, frb;
size_t wpos, wbit, iw, vbo;
struct buffer_head *bh = NULL;
CLST lcn, clen;
wnd->uptodated = 0;
wnd->extent_max = 0;
wnd->extent_min = MINUS_ONE_T;
wnd->total_zeroes = 0;
vbo = 0;
for (iw = 0; iw < wnd->nwnd; iw++) {
if (iw + 1 == wnd->nwnd)
wbits = wnd->bits_last;
if (wnd->inited) {
if (!wnd->free_bits[iw]) {
/* All ones. */
if (prev_tail) {
wnd_add_free_ext(wnd,
vbo * 8 - prev_tail,
prev_tail, true);
prev_tail = 0;
}
goto next_wnd;
}
if (wbits == wnd->free_bits[iw]) {
/* All zeroes. */
prev_tail += wbits;
wnd->total_zeroes += wbits;
goto next_wnd;
}
}
if (!len) {
u32 off = vbo & sbi->cluster_mask;
if (!run_lookup_entry(&wnd->run, vbo >> cluster_bits,
&lcn, &clen, NULL)) {
err = -ENOENT;
goto out;
}
lbo = ((u64)lcn << cluster_bits) + off;
len = ((u64)clen << cluster_bits) - off;
}
bh = ntfs_bread(sb, lbo >> sb->s_blocksize_bits);
if (!bh) {
err = -EIO;
goto out;
}
used = ntfs_bitmap_weight_le(bh->b_data, wbits);
if (used < wbits) {
frb = wbits - used;
wnd->free_bits[iw] = frb;
wnd->total_zeroes += frb;
}
wpos = 0;
wbit = vbo * 8;
if (wbit + wbits > wnd->nbits)
wbits = wnd->nbits - wbit;
do {
used = find_next_zero_bit_le(bh->b_data, wbits, wpos);
if (used > wpos && prev_tail) {
wnd_add_free_ext(wnd, wbit + wpos - prev_tail,
prev_tail, true);
prev_tail = 0;
}
wpos = used;
if (wpos >= wbits) {
/* No free blocks. */
prev_tail = 0;
break;
}
frb = find_next_bit_le(bh->b_data, wbits, wpos);
if (frb >= wbits) {
/* Keep last free block. */
prev_tail += frb - wpos;
break;
}
wnd_add_free_ext(wnd, wbit + wpos - prev_tail,
frb + prev_tail - wpos, true);
/* Skip free block and first '1'. */
wpos = frb + 1;
/* Reset previous tail. */
prev_tail = 0;
} while (wpos < wbits);
next_wnd:
if (bh)
put_bh(bh);
bh = NULL;
vbo += blocksize;
if (len) {
len -= blocksize;
lbo += blocksize;
}
}
/* Add last block. */
if (prev_tail)
wnd_add_free_ext(wnd, wnd->nbits - prev_tail, prev_tail, true);
/*
* Before init cycle wnd->uptodated was 0.
* If any errors or limits occurs while initialization then
* wnd->uptodated will be -1.
* If 'uptodated' is still 0 then Tree is really updated.
*/
if (!wnd->uptodated)
wnd->uptodated = 1;
if (wnd->zone_bit != wnd->zone_end) {
size_t zlen = wnd->zone_end - wnd->zone_bit;
wnd->zone_end = wnd->zone_bit;
wnd_zone_set(wnd, wnd->zone_bit, zlen);
}
out:
return err;
}
int wnd_init(struct wnd_bitmap *wnd, struct super_block *sb, size_t nbits)
{
int err;
u32 blocksize = sb->s_blocksize;
u32 wbits = blocksize * 8;
init_rwsem(&wnd->rw_lock);
wnd->sb = sb;
wnd->nbits = nbits;
wnd->total_zeroes = nbits;
wnd->extent_max = MINUS_ONE_T;
wnd->zone_bit = wnd->zone_end = 0;
wnd->nwnd = bytes_to_block(sb, bitmap_size(nbits));
wnd->bits_last = nbits & (wbits - 1);
if (!wnd->bits_last)
wnd->bits_last = wbits;
wnd->free_bits = kcalloc(wnd->nwnd, sizeof(u16), GFP_NOFS | __GFP_NOWARN);
if (!wnd->free_bits)
return -ENOMEM;
err = wnd_rescan(wnd);
if (err)
return err;
wnd->inited = true;
return 0;
}
/*
* wnd_map - Call sb_bread for requested window.
*/
static struct buffer_head *wnd_map(struct wnd_bitmap *wnd, size_t iw)
{
size_t vbo;
CLST lcn, clen;
struct super_block *sb = wnd->sb;
struct ntfs_sb_info *sbi;
struct buffer_head *bh;
u64 lbo;
sbi = sb->s_fs_info;
vbo = (u64)iw << sb->s_blocksize_bits;
if (!run_lookup_entry(&wnd->run, vbo >> sbi->cluster_bits, &lcn, &clen,
NULL)) {
return ERR_PTR(-ENOENT);
}
lbo = ((u64)lcn << sbi->cluster_bits) + (vbo & sbi->cluster_mask);
bh = ntfs_bread(wnd->sb, lbo >> sb->s_blocksize_bits);
if (!bh)
return ERR_PTR(-EIO);
return bh;
}
/*
* wnd_set_free - Mark the bits range from bit to bit + bits as free.
*/
int wnd_set_free(struct wnd_bitmap *wnd, size_t bit, size_t bits)
{
int err = 0;
struct super_block *sb = wnd->sb;
size_t bits0 = bits;
u32 wbits = 8 * sb->s_blocksize;
size_t iw = bit >> (sb->s_blocksize_bits + 3);
u32 wbit = bit & (wbits - 1);
struct buffer_head *bh;
while (iw < wnd->nwnd && bits) {
u32 tail, op;
if (iw + 1 == wnd->nwnd)
wbits = wnd->bits_last;
tail = wbits - wbit;
op = min_t(u32, tail, bits);
bh = wnd_map(wnd, iw);
if (IS_ERR(bh)) {
err = PTR_ERR(bh);
break;
}
lock_buffer(bh);
ntfs_bitmap_clear_le(bh->b_data, wbit, op);
wnd->free_bits[iw] += op;
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
unlock_buffer(bh);
put_bh(bh);
wnd->total_zeroes += op;
bits -= op;
wbit = 0;
iw += 1;
}
wnd_add_free_ext(wnd, bit, bits0, false);
return err;
}
/*
* wnd_set_used - Mark the bits range from bit to bit + bits as used.
*/
int wnd_set_used(struct wnd_bitmap *wnd, size_t bit, size_t bits)
{
int err = 0;
struct super_block *sb = wnd->sb;
size_t bits0 = bits;
size_t iw = bit >> (sb->s_blocksize_bits + 3);
u32 wbits = 8 * sb->s_blocksize;
u32 wbit = bit & (wbits - 1);
struct buffer_head *bh;
while (iw < wnd->nwnd && bits) {
u32 tail, op;
if (unlikely(iw + 1 == wnd->nwnd))
wbits = wnd->bits_last;
tail = wbits - wbit;
op = min_t(u32, tail, bits);
bh = wnd_map(wnd, iw);
if (IS_ERR(bh)) {
err = PTR_ERR(bh);
break;
}
lock_buffer(bh);
ntfs_bitmap_set_le(bh->b_data, wbit, op);
wnd->free_bits[iw] -= op;
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
unlock_buffer(bh);
put_bh(bh);
wnd->total_zeroes -= op;
bits -= op;
wbit = 0;
iw += 1;
}
if (!RB_EMPTY_ROOT(&wnd->start_tree))
wnd_remove_free_ext(wnd, bit, bits0);
return err;
}
/*
* wnd_set_used_safe - Mark the bits range from bit to bit + bits as used.
*
* Unlikely wnd_set_used/wnd_set_free this function is not full trusted.
* It scans every bit in bitmap and marks free bit as used.
* @done - how many bits were marked as used.
*
* NOTE: normally *done should be 0.
*/
int wnd_set_used_safe(struct wnd_bitmap *wnd, size_t bit, size_t bits,
size_t *done)
{
size_t i, from = 0, len = 0;
int err = 0;
*done = 0;
for (i = 0; i < bits; i++) {
if (wnd_is_free(wnd, bit + i, 1)) {
if (!len)
from = bit + i;
len += 1;
} else if (len) {
err = wnd_set_used(wnd, from, len);
*done += len;
len = 0;
if (err)
break;
}
}
if (len) {
/* last fragment. */
err = wnd_set_used(wnd, from, len);
*done += len;
}
return err;
}
/*
* wnd_is_free_hlp
*
* Return: True if all clusters [bit, bit+bits) are free (bitmap only).
*/
static bool wnd_is_free_hlp(struct wnd_bitmap *wnd, size_t bit, size_t bits)
{
struct super_block *sb = wnd->sb;
size_t iw = bit >> (sb->s_blocksize_bits + 3);
u32 wbits = 8 * sb->s_blocksize;
u32 wbit = bit & (wbits - 1);
while (iw < wnd->nwnd && bits) {
u32 tail, op;
if (unlikely(iw + 1 == wnd->nwnd))
wbits = wnd->bits_last;
tail = wbits - wbit;
op = min_t(u32, tail, bits);
if (wbits != wnd->free_bits[iw]) {
bool ret;
struct buffer_head *bh = wnd_map(wnd, iw);
if (IS_ERR(bh))
return false;
ret = are_bits_clear(bh->b_data, wbit, op);
put_bh(bh);
if (!ret)
return false;
}
bits -= op;
wbit = 0;
iw += 1;
}
return true;
}
/*
* wnd_is_free
*
* Return: True if all clusters [bit, bit+bits) are free.
*/
bool wnd_is_free(struct wnd_bitmap *wnd, size_t bit, size_t bits)
{
bool ret;
struct rb_node *n;
size_t end;
struct e_node *e;
if (RB_EMPTY_ROOT(&wnd->start_tree))
goto use_wnd;
n = rb_lookup(&wnd->start_tree, bit);
if (!n)
goto use_wnd;
e = rb_entry(n, struct e_node, start.node);
end = e->start.key + e->count.key;
if (bit < end && bit + bits <= end)
return true;
use_wnd:
ret = wnd_is_free_hlp(wnd, bit, bits);
return ret;
}
/*
* wnd_is_used
*
* Return: True if all clusters [bit, bit+bits) are used.
*/
bool wnd_is_used(struct wnd_bitmap *wnd, size_t bit, size_t bits)
{
bool ret = false;
struct super_block *sb = wnd->sb;
size_t iw = bit >> (sb->s_blocksize_bits + 3);
u32 wbits = 8 * sb->s_blocksize;
u32 wbit = bit & (wbits - 1);
size_t end;
struct rb_node *n;
struct e_node *e;
if (RB_EMPTY_ROOT(&wnd->start_tree))
goto use_wnd;
end = bit + bits;
n = rb_lookup(&wnd->start_tree, end - 1);
if (!n)
goto use_wnd;
e = rb_entry(n, struct e_node, start.node);
if (e->start.key + e->count.key > bit)
return false;
use_wnd:
while (iw < wnd->nwnd && bits) {
u32 tail, op;
if (unlikely(iw + 1 == wnd->nwnd))
wbits = wnd->bits_last;
tail = wbits - wbit;
op = min_t(u32, tail, bits);
if (wnd->free_bits[iw]) {
bool ret;
struct buffer_head *bh = wnd_map(wnd, iw);
if (IS_ERR(bh))
goto out;
ret = are_bits_set(bh->b_data, wbit, op);
put_bh(bh);
if (!ret)
goto out;
}
bits -= op;
wbit = 0;
iw += 1;
}
ret = true;
out:
return ret;
}
/*
* wnd_find - Look for free space.
*
* - flags - BITMAP_FIND_XXX flags
*
* Return: 0 if not found.
*/
size_t wnd_find(struct wnd_bitmap *wnd, size_t to_alloc, size_t hint,
size_t flags, size_t *allocated)
{
struct super_block *sb;
u32 wbits, wpos, wzbit, wzend;
size_t fnd, max_alloc, b_len, b_pos;
size_t iw, prev_tail, nwnd, wbit, ebit, zbit, zend;
size_t to_alloc0 = to_alloc;
const struct e_node *e;
const struct rb_node *pr, *cr;
u8 log2_bits;
bool fbits_valid;
struct buffer_head *bh;
/* Fast checking for available free space. */
if (flags & BITMAP_FIND_FULL) {
size_t zeroes = wnd_zeroes(wnd);