summaryrefslogtreecommitdiffstats
path: root/fs/btrfs/sysfs.c
blob: 786f4e4c654280b4a283acac909dc4f3c150df2c (plain)
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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 */

#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/bug.h>
#include <crypto/hash.h>

#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "sysfs.h"
#include "volumes.h"
#include "space-info.h"
#include "block-group.h"

struct btrfs_feature_attr {
	struct kobj_attribute kobj_attr;
	enum btrfs_feature_set feature_set;
	u64 feature_bit;
};

/* For raid type sysfs entries */
struct raid_kobject {
	u64 flags;
	struct kobject kobj;
};

#define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)			\
{									\
	.attr	= { .name = __stringify(_name), .mode = _mode },	\
	.show	= _show,						\
	.store	= _store,						\
}

#define BTRFS_ATTR_RW(_prefix, _name, _show, _store)			\
	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
			__INIT_KOBJ_ATTR(_name, 0644, _show, _store)

#define BTRFS_ATTR(_prefix, _name, _show)				\
	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
			__INIT_KOBJ_ATTR(_name, 0444, _show, NULL)

#define BTRFS_ATTR_PTR(_prefix, _name)					\
	(&btrfs_attr_##_prefix##_##_name.attr)

#define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
static struct btrfs_feature_attr btrfs_attr_features_##_name = {	     \
	.kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,			     \
				      btrfs_feature_attr_show,		     \
				      btrfs_feature_attr_store),	     \
	.feature_set	= _feature_set,					     \
	.feature_bit	= _feature_prefix ##_## _feature_bit,		     \
}
#define BTRFS_FEAT_ATTR_PTR(_name)					     \
	(&btrfs_attr_features_##_name.kobj_attr.attr)

#define BTRFS_FEAT_ATTR_COMPAT(name, feature) \
	BTRFS_FEAT_ATTR(name, FEAT_COMPAT, BTRFS_FEATURE_COMPAT, feature)
#define BTRFS_FEAT_ATTR_COMPAT_RO(name, feature) \
	BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature)
#define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \
	BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature)

static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);

static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
{
	return container_of(a, struct btrfs_feature_attr, kobj_attr);
}

static struct kobj_attribute *attr_to_btrfs_attr(struct attribute *attr)
{
	return container_of(attr, struct kobj_attribute, attr);
}

static struct btrfs_feature_attr *attr_to_btrfs_feature_attr(
		struct attribute *attr)
{
	return to_btrfs_feature_attr(attr_to_btrfs_attr(attr));
}

static u64 get_features(struct btrfs_fs_info *fs_info,
			enum btrfs_feature_set set)
{
	struct btrfs_super_block *disk_super = fs_info->super_copy;
	if (set == FEAT_COMPAT)
		return btrfs_super_compat_flags(disk_super);
	else if (set == FEAT_COMPAT_RO)
		return btrfs_super_compat_ro_flags(disk_super);
	else
		return btrfs_super_incompat_flags(disk_super);
}

static void set_features(struct btrfs_fs_info *fs_info,
			 enum btrfs_feature_set set, u64 features)
{
	struct btrfs_super_block *disk_super = fs_info->super_copy;
	if (set == FEAT_COMPAT)
		btrfs_set_super_compat_flags(disk_super, features);
	else if (set == FEAT_COMPAT_RO)
		btrfs_set_super_compat_ro_flags(disk_super, features);
	else
		btrfs_set_super_incompat_flags(disk_super, features);
}

static int can_modify_feature(struct btrfs_feature_attr *fa)
{
	int val = 0;
	u64 set, clear;
	switch (fa->feature_set) {
	case FEAT_COMPAT:
		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
		break;
	case FEAT_COMPAT_RO:
		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
		break;
	case FEAT_INCOMPAT:
		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
		break;
	default:
		pr_warn("btrfs: sysfs: unknown feature set %d\n",
				fa->feature_set);
		return 0;
	}

	if (set & fa->feature_bit)
		val |= 1;
	if (clear & fa->feature_bit)
		val |= 2;

	return val;
}

static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
				       struct kobj_attribute *a, char *buf)
{
	int val = 0;
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
	if (fs_info) {
		u64 features = get_features(fs_info, fa->feature_set);
		if (features & fa->feature_bit)
			val = 1;
	} else
		val = can_modify_feature(fa);

	return snprintf(buf, PAGE_SIZE, "%d\n", val);
}

static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
					struct kobj_attribute *a,
					const char *buf, size_t count)
{
	struct btrfs_fs_info *fs_info;
	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
	u64 features, set, clear;
	unsigned long val;
	int ret;

	fs_info = to_fs_info(kobj);
	if (!fs_info)
		return -EPERM;

	if (sb_rdonly(fs_info->sb))
		return -EROFS;

	ret = kstrtoul(skip_spaces(buf), 0, &val);
	if (ret)
		return ret;

	if (fa->feature_set == FEAT_COMPAT) {
		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
	} else if (fa->feature_set == FEAT_COMPAT_RO) {
		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
	} else {
		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
	}

	features = get_features(fs_info, fa->feature_set);

	/* Nothing to do */
	if ((val && (features & fa->feature_bit)) ||
	    (!val && !(features & fa->feature_bit)))
		return count;

	if ((val && !(set & fa->feature_bit)) ||
	    (!val && !(clear & fa->feature_bit))) {
		btrfs_info(fs_info,
			"%sabling feature %s on mounted fs is not supported.",
			val ? "En" : "Dis", fa->kobj_attr.attr.name);
		return -EPERM;
	}

	btrfs_info(fs_info, "%s %s feature flag",
		   val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);

	spin_lock(&fs_info->super_lock);
	features = get_features(fs_info, fa->feature_set);
	if (val)
		features |= fa->feature_bit;
	else
		features &= ~fa->feature_bit;
	set_features(fs_info, fa->feature_set, features);
	spin_unlock(&fs_info->super_lock);

	/*
	 * We don't want to do full transaction commit from inside sysfs
	 */
	btrfs_set_pending(fs_info, COMMIT);
	wake_up_process(fs_info->transaction_kthread);

	return count;
}

static umode_t btrfs_feature_visible(struct kobject *kobj,
				     struct attribute *attr, int unused)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
	umode_t mode = attr->mode;

	if (fs_info) {
		struct btrfs_feature_attr *fa;
		u64 features;

		fa = attr_to_btrfs_feature_attr(attr);
		features = get_features(fs_info, fa->feature_set);

		if (can_modify_feature(fa))
			mode |= S_IWUSR;
		else if (!(features & fa->feature_bit))
			mode = 0;
	}

	return mode;
}

BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);

static struct attribute *btrfs_supported_feature_attrs[] = {
	BTRFS_FEAT_ATTR_PTR(mixed_backref),
	BTRFS_FEAT_ATTR_PTR(default_subvol),
	BTRFS_FEAT_ATTR_PTR(mixed_groups),
	BTRFS_FEAT_ATTR_PTR(compress_lzo),
	BTRFS_FEAT_ATTR_PTR(compress_zstd),
	BTRFS_FEAT_ATTR_PTR(big_metadata),
	BTRFS_FEAT_ATTR_PTR(extended_iref),
	BTRFS_FEAT_ATTR_PTR(raid56),
	BTRFS_FEAT_ATTR_PTR(skinny_metadata),
	BTRFS_FEAT_ATTR_PTR(no_holes),
	BTRFS_FEAT_ATTR_PTR(metadata_uuid),
	BTRFS_FEAT_ATTR_PTR(free_space_tree),
	NULL
};

/*
 * Features which depend on feature bits and may differ between each fs.
 *
 * /sys/fs/btrfs/features lists all available features of this kernel while
 * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
 * can be changed online.
 */
static const struct attribute_group btrfs_feature_attr_group = {
	.name = "features",
	.is_visible = btrfs_feature_visible,
	.attrs = btrfs_supported_feature_attrs,
};

static ssize_t rmdir_subvol_show(struct kobject *kobj,
				 struct kobj_attribute *ka, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "0\n");
}
BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);

static ssize_t supported_checksums_show(struct kobject *kobj,
					struct kobj_attribute *a, char *buf)
{
	ssize_t ret = 0;
	int i;

	for (i = 0; i < btrfs_get_num_csums(); i++) {
		/*
		 * This "trick" only works as long as 'enum btrfs_csum_type' has
		 * no holes in it
		 */
		ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
				(i == 0 ? "" : " "), btrfs_super_csum_name(i));

	}

	ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n");
	return ret;
}
BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);

static struct attribute *btrfs_supported_static_feature_attrs[] = {
	BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
	BTRFS_ATTR_PTR(static_feature, supported_checksums),
	NULL
};

/*
 * Features which only depend on kernel version.
 *
 * These are listed in /sys/fs/btrfs/features along with
 * btrfs_feature_attr_group
 */
static const struct attribute_group btrfs_static_feature_attr_group = {
	.name = "features",
	.attrs = btrfs_supported_static_feature_attrs,
};

#ifdef CONFIG_BTRFS_DEBUG

/*
 * Runtime debugging exported via sysfs
 *
 * /sys/fs/btrfs/debug - applies to module or all filesystems
 * /sys/fs/btrfs/UUID  - applies only to the given filesystem
 */
static struct attribute *btrfs_debug_feature_attrs[] = {
	NULL
};

static const struct attribute_group btrfs_debug_feature_attr_group = {
	.name = "debug",
	.attrs = btrfs_debug_feature_attrs,
};

#endif

static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
{
	u64 val;
	if (lock)
		spin_lock(lock);
	val = *value_ptr;
	if (lock)
		spin_unlock(lock);
	return snprintf(buf, PAGE_SIZE, "%llu\n", val);
}

static ssize_t global_rsv_size_show(struct kobject *kobj,
				    struct kobj_attribute *ka, char *buf)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
	return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
}
BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);

static ssize_t global_rsv_reserved_show(struct kobject *kobj,
					struct kobj_attribute *a, char *buf)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
	return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
}
BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);

#define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
#define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)

static ssize_t raid_bytes_show(struct kobject *kobj,
			       struct kobj_attribute *attr, char *buf);
BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
BTRFS_ATTR(raid, used_bytes, raid_bytes_show);

static ssize_t raid_bytes_show(struct kobject *kobj,
			       struct kobj_attribute *attr, char *buf)

{
	struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
	struct btrfs_block_group_cache *block_group;
	int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
	u64 val = 0;

	down_read(&sinfo->groups_sem);
	list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
		if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
			val += block_group->length;
		else
			val += block_group->used;
	}
	up_read(&sinfo->groups_sem);
	return snprintf(buf, PAGE_SIZE, "%llu\n", val);
}

static struct attribute *raid_attrs[] = {
	BTRFS_ATTR_PTR(raid, total_bytes),
	BTRFS_ATTR_PTR(raid, used_bytes),
	NULL
};
ATTRIBUTE_GROUPS(raid);

static void release_raid_kobj(struct kobject *kobj)
{
	kfree(to_raid_kobj(kobj));
}

static struct kobj_type btrfs_raid_ktype = {
	.sysfs_ops = &kobj_sysfs_ops,
	.release = release_raid_kobj,
	.default_groups = raid_groups,
};

#define SPACE_INFO_ATTR(field)						\
static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,	\
					     struct kobj_attribute *a,	\
					     char *buf)			\
{									\
	struct btrfs_space_info *sinfo = to_space_info(kobj);		\
	return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);	\
}									\
BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)

static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
						       struct kobj_attribute *a,
						       char *buf)
{
	struct btrfs_space_info *sinfo = to_space_info(kobj);
	s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
	return snprintf(buf, PAGE_SIZE, "%lld\n", val);
}

SPACE_INFO_ATTR(flags);
SPACE_INFO_ATTR(total_bytes);
SPACE_INFO_ATTR(bytes_used);
SPACE_INFO_ATTR(bytes_pinned);
SPACE_INFO_ATTR(bytes_reserved);
SPACE_INFO_ATTR(bytes_may_use);
SPACE_INFO_ATTR(bytes_readonly);
SPACE_INFO_ATTR(disk_used);
SPACE_INFO_ATTR(disk_total);
BTRFS_ATTR(space_info, total_bytes_pinned,
	   btrfs_space_info_show_total_bytes_pinned);

static struct attribute *space_info_attrs[] = {
	BTRFS_ATTR_PTR(space_info, flags),
	BTRFS_ATTR_PTR(space_info, total_bytes),
	BTRFS_ATTR_PTR(space_info, bytes_used),
	BTRFS_ATTR_PTR(space_info, bytes_pinned),
	BTRFS_ATTR_PTR(space_info, bytes_reserved),
	BTRFS_ATTR_PTR(space_info, bytes_may_use),
	BTRFS_ATTR_PTR(space_info, bytes_readonly),
	BTRFS_ATTR_PTR(space_info, disk_used),
	BTRFS_ATTR_PTR(space_info, disk_total),
	BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
	NULL,
};
ATTRIBUTE_GROUPS(space_info);

static void space_info_release(struct kobject *kobj)
{
	struct btrfs_space_info *sinfo = to_space_info(kobj);
	percpu_counter_destroy(&sinfo->total_bytes_pinned);
	kfree(sinfo);
}

static struct kobj_type space_info_ktype = {
	.sysfs_ops = &kobj_sysfs_ops,
	.release = space_info_release,
	.default_groups = space_info_groups,
};

static const struct attribute *allocation_attrs[] = {
	BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
	BTRFS_ATTR_PTR(allocation, global_rsv_size),
	NULL,
};

static ssize_t btrfs_label_show(struct kobject *kobj,
				struct kobj_attribute *a, char *buf)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
	char *label = fs_info->super_copy->label;
	ssize_t ret;

	spin_lock(&fs_info->super_lock);
	ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
	spin_unlock(&fs_info->super_lock);

	return ret;
}

static ssize_t btrfs_label_store(struct kobject *kobj,
				 struct kobj_attribute *a,
				 const char *buf, size_t len)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
	size_t p_len;

	if (!fs_info)
		return -EPERM;

	if (sb_rdonly(fs_info->sb))
		return -EROFS;

	/*
	 * p_len is the len until the first occurrence of either
	 * '\n' or '\0'
	 */
	p_len = strcspn(buf, "\n");

	if (p_len >= BTRFS_LABEL_SIZE)
		return -EINVAL;

	spin_lock(&fs_info->super_lock);
	memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
	memcpy(fs_info->super_copy->label, buf, p_len);
	spin_unlock(&fs_info->super_lock);

	/*
	 * We don't want to do full transaction commit from inside sysfs
	 */
	btrfs_set_pending(fs_info, COMMIT);
	wake_up_process(fs_info->transaction_kthread);

	return len;
}
BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);

static ssize_t btrfs_nodesize_show(struct kobject *kobj,
				struct kobj_attribute *a, char *buf)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
}

BTRFS_ATTR(, nodesize, btrfs_nodesize_show);

static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
				struct kobj_attribute *a, char *buf)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

	return snprintf(buf, PAGE_SIZE, "%u\n",
			fs_info->super_copy->sectorsize);
}

BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);

static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
				struct kobj_attribute *a, char *buf)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

	return snprintf(buf, PAGE_SIZE, "%u\n",
			fs_info->super_copy->sectorsize);
}

BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);

static ssize_t quota_override_show(struct kobject *kobj,
				   struct kobj_attribute *a, char *buf)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
	int quota_override;

	quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
	return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
}

static ssize_t quota_override_store(struct kobject *kobj,
				    struct kobj_attribute *a,
				    const char *buf, size_t len)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
	unsigned long knob;
	int err;

	if (!fs_info)
		return -EPERM;

	if (!capable(CAP_SYS_RESOURCE))
		return -EPERM;

	err = kstrtoul(buf, 10, &knob);
	if (err)
		return err;
	if (knob > 1)
		return -EINVAL;

	if (knob)
		set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
	else
		clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);

	return len;
}

BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);

static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
				struct kobj_attribute *a, char *buf)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);

	return snprintf(buf, PAGE_SIZE, "%pU\n",
			fs_info->fs_devices->metadata_uuid);
}

BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);

static ssize_t btrfs_checksum_show(struct kobject *kobj,
				   struct kobj_attribute *a, char *buf)
{
	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
	u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);

	return snprintf(buf, PAGE_SIZE, "%s (%s)\n",
			btrfs_super_csum_name(csum_type),
			crypto_shash_driver_name(fs_info->csum_shash));
}

BTRFS_ATTR(, checksum, btrfs_checksum_show);

static const struct attribute *btrfs_attrs[] = {
	BTRFS_ATTR_PTR(, label),
	BTRFS_ATTR_PTR(, nodesize),
	BTRFS_ATTR_PTR(, sectorsize),
	BTRFS_ATTR_PTR(, clone_alignment),
	BTRFS_ATTR_PTR(, quota_override),
	BTRFS_ATTR_PTR(, metadata_uuid),
	BTRFS_ATTR_PTR(, checksum),
	NULL,
};

static void btrfs_release_fsid_kobj(struct kobject *kobj)
{
	struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);

	memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
	complete(&fs_devs->kobj_unregister);
}

static struct kobj_type btrfs_ktype = {
	.sysfs_ops	= &kobj_sysfs_ops,
	.release	= btrfs_release_fsid_kobj,
};

static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
{
	if (kobj->ktype != &btrfs_ktype)
		return NULL;
	return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
}

static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
{
	if (kobj->ktype != &btrfs_ktype)
		return NULL;
	return to_fs_devs(kobj)->fs_info;
}

#define NUM_FEATURE_BITS 64
#define BTRFS_FEATURE_NAME_MAX 13
static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];

static const u64 supported_feature_masks[FEAT_MAX] = {
	[FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
	[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
	[FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
};

static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
{
	int set;

	for (set = 0; set < FEAT_MAX; set++) {
		int i;
		struct attribute *attrs[2];
		struct attribute_group agroup = {
			.name = "features",
			.attrs = attrs,
		};
		u64 features = get_features(fs_info, set);
		features &= ~supported_feature_masks[set];

		if (!features)
			continue;

		attrs[1] = NULL;
		for (i = 0; i < NUM_FEATURE_BITS; i++) {
			struct btrfs_feature_attr *fa;

			if (!(features & (1ULL << i)))
				continue;

			fa = &btrfs_feature_attrs[set][i];
			attrs[0] = &fa->kobj_attr.attr;
			if (add) {
				int ret;
				ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
							&agroup);
				if (ret)
					return ret;
			} else
				sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
						    &agroup);
		}

	}
	return 0;
}

static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
{
	if (fs_devs->device_dir_kobj) {
		kobject_del(fs_devs->device_dir_kobj);
		kobject_put(fs_devs->device_dir_kobj);
		fs_devs->device_dir_kobj = NULL;
	}

	if (fs_devs->fsid_kobj.state_initialized) {
		kobject_del(&fs_devs->fsid_kobj);
		kobject_put(&fs_devs->fsid_kobj);
		wait_for_completion(&fs_devs->kobj_unregister);
	}
}

/* when fs_devs is NULL it will remove all fsid kobject */
void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
{
	struct list_head *fs_uuids = btrfs_get_fs_uuids();

	if (fs_devs) {
		__btrfs_sysfs_remove_fsid(fs_devs);
		return;
	}

	list_for_each_entry(fs_devs, fs_uuids, fs_list) {
		__btrfs_sysfs_remove_fsid(fs_devs);
	}
}

void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
{
	btrfs_reset_fs_info_ptr(fs_info);

	if (fs_info->space_info_kobj) {
		sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
		kobject_del(fs_info->space_info_kobj);
		kobject_put(fs_info->space_info_kobj);
	}
	addrm_unknown_feature_attrs(fs_info, false);
	sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
	sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
	btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
}

static const char * const btrfs_feature_set_names[FEAT_MAX] = {
	[FEAT_COMPAT]	 = "compat",
	[FEAT_COMPAT_RO] = "compat_ro",
	[FEAT_INCOMPAT]	 = "incompat",
};

const char * const btrfs_feature_set_name(enum btrfs_feature_set set)
{
	return btrfs_feature_set_names[set];
}

char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
{
	size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
	int len = 0;
	int i;
	char *str;

	str = kmalloc(bufsize, GFP_KERNEL);
	if (!str)
		return str;

	for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
		const char *name;

		if (!(flags & (1ULL << i)))
			continue;

		name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
		len += snprintf(str + len, bufsize - len, "%s%s",
				len ? "," : "", name);
	}

	return str;
}

static void init_feature_attrs(void)
{
	struct btrfs_feature_attr *fa;
	int set, i;

	BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
		     ARRAY_SIZE(btrfs_feature_attrs));
	BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
		     ARRAY_SIZE(btrfs_feature_attrs[0]));

	memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
	memset(btrfs_unknown_feature_names, 0,
	       sizeof(btrfs_unknown_feature_names));

	for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
		struct btrfs_feature_attr *sfa;
		struct attribute *a = btrfs_supported_feature_attrs[i];
		int bit;
		sfa = attr_to_btrfs_feature_attr(a);
		bit = ilog2(sfa->feature_bit);
		fa = &btrfs_feature_attrs[sfa->feature_set][bit];

		fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
	}

	for (set = 0; set < FEAT_MAX; set++) {
		for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
			char *name = btrfs_unknown_feature_names[set][i];
			fa = &btrfs_feature_attrs[set][i];

			if (fa->kobj_attr.attr.name)
				continue;

			snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
				 btrfs_feature_set_names[set], i);

			fa->kobj_attr.attr.name = name;
			fa->kobj_attr.attr.mode = S_IRUGO;
			fa->feature_set = set;
			fa->feature_bit = 1ULL << i;
		}
	}
}

/*
 * Create a sysfs entry for a given block group type at path
 * /sys/fs/btrfs/UUID/allocation/data/TYPE
 */
void btrfs_sysfs_add_block_group_type(struct btrfs_block_group_cache *cache)
{
	struct btrfs_fs_info *fs_info = cache->fs_info;
	struct btrfs_space_info *space_info = cache->space_info;
	struct raid_kobject *rkobj;
	const int index = btrfs_bg_flags_to_raid_index(cache->flags);
	unsigned int nofs_flag;
	int ret;

	/*
	 * Setup a NOFS context because kobject_add(), deep in its call chain,
	 * does GFP_KERNEL allocations, and we are often called in a context
	 * where if reclaim is triggered we can deadlock (we are either holding
	 * a transaction handle or some lock required for a transaction
	 * commit).
	 */
	nofs_flag = memalloc_nofs_save();

	rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
	if (!rkobj) {
		memalloc_nofs_restore(nofs_flag);
		btrfs_warn(cache->fs_info,
				"couldn't alloc memory for raid level kobject");
		return;
	}

	rkobj->flags = cache->flags;
	kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
	ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
			  btrfs_bg_type_to_raid_name(rkobj->flags));
	memalloc_nofs_restore(nofs_flag);
	if (ret) {
		kobject_put(&rkobj->kobj);
		btrfs_warn(fs_info,
			"failed to add kobject for block cache, ignoring");
		return;
	}

	space_info->block_group_kobjs[index] = &rkobj->kobj;
}

/*
 * Remove sysfs directories for all block group types of a given space info and
 * the space info as well
 */
void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
{
	int i;

	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
		struct kobject *kobj;

		kobj = space_info->block_group_kobjs[i];
		space_info->block_group_kobjs[i] = NULL;
		if (kobj) {
			kobject_del(kobj);
			kobject_put(kobj);
		}
	}
	kobject_del(&space_info->kobj);
	kobject_put(&space_info->kobj);
}

static const char *alloc_name(u64 flags)
{
	switch (flags) {
	case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
		return "mixed";
	case BTRFS_BLOCK_GROUP_METADATA:
		return "metadata";
	case BTRFS_BLOCK_GROUP_DATA:
		return "data";
	case BTRFS_BLOCK_GROUP_SYSTEM:
		return "system";
	default:
		WARN_ON(1);
		return "invalid-combination";
	};
}

/*
 * Create a sysfs entry for a space info type at path
 * /sys/fs/btrfs/UUID/allocation/TYPE
 */
int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
				    struct btrfs_space_info *space_info)
{
	int ret;

	ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
				   fs_info->space_info_kobj, "%s",
				   alloc_name(space_info->flags));
	if (ret) {
		kobject_put(&space_info->kobj);
		return ret;
	}

	return 0;
}

/* when one_device is NULL, it removes all device links */

int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
		struct btrfs_device *one_device)
{
	struct hd_struct *disk;
	struct kobject *disk_kobj;

	if (!fs_devices->device_dir_kobj)
		return -EINVAL;

	if (one_device && one_device->bdev) {
		disk = one_device->bdev->bd_part;
		disk_kobj = &part_to_dev(disk)->kobj;

		sysfs_remove_link(fs_devices->device_dir_kobj,
						disk_kobj->name);
	}

	if (one_device)
		return 0;

	list_for_each_entry(one_device,
			&fs_devices->devices, dev_list) {
		if (!one_device->bdev)
			continue;
		disk = one_device->bdev->bd_part;
		disk_kobj = &part_to_dev(disk)->kobj;

		sysfs_remove_link(fs_devices->device_dir_kobj,
						disk_kobj->name);
	}

	return 0;
}

int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
{
	if (!fs_devs->device_dir_kobj)
		fs_devs->device_dir_kobj = kobject_create_and_add("devices",
						&fs_devs->fsid_kobj);

	if (!fs_devs->device_dir_kobj)
		return -ENOMEM;

	return 0;
}

int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
				struct btrfs_device *one_device)
{
	int error = 0;
	struct btrfs_device *dev;

	list_for_each_entry(dev, &fs_devices->devices, dev_list) {
		struct hd_struct *disk;
		struct kobject *disk_kobj;

		if (!dev->bdev)
			continue;

		if (one_device && one_device != dev)
			continue;

		disk = dev->bdev->bd_part;
		disk_kobj = &part_to_dev(disk)->kobj;

		error = sysfs_create_link(fs_devices->device_dir_kobj,
					  disk_kobj, disk_kobj->name);
		if (error)
			break;
	}

	return error;
}

void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
{
	int ret;

	ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
	if (ret)
		pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
			action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
			&disk_to_dev(bdev->bd_disk)->kobj);
}

void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices,
				    const u8 *fsid)
{
	char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];

	/*
	 * Sprouting changes fsid of the mounted filesystem, rename the fsid
	 * directory
	 */
	snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fsid);
	if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
		btrfs_warn(fs_devices->fs_info,
				"sysfs: failed to create fsid for sprout");
}

/* /sys/fs/btrfs/ entry */
static struct kset *btrfs_kset;

/*
 * Can be called by the device discovery thread.
 * And parent can be specified for seed device
 */
int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
				struct kobject *parent)
{
	int error;

	init_completion(&fs_devs->kobj_unregister);
	fs_devs->fsid_kobj.kset = btrfs_kset;
	error = kobject_init_and_add(&fs_devs->fsid_kobj,
				&btrfs_ktype, parent, "%pU", fs_devs->fsid);
	if (error) {
		kobject_put(&fs_devs->fsid_kobj);
		return error;
	}

	return 0;
}

int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
{
	int error;
	struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
	struct kobject *fsid_kobj = &fs_devs->fsid_kobj;

	btrfs_set_fs_info_ptr(fs_info);

	error = btrfs_sysfs_add_device_link(fs_devs, NULL);
	if (error)
		return error;

	error = sysfs_create_files(fsid_kobj, btrfs_attrs);
	if (error) {
		btrfs_sysfs_rm_device_link(fs_devs, NULL);
		return error;
	}

	error = sysfs_create_group(fsid_kobj,
				   &btrfs_feature_attr_group);
	if (error)
		goto failure;

#ifdef CONFIG_BTRFS_DEBUG
	error = sysfs_create_group(fsid_kobj,
				   &btrfs_debug_feature_attr_group);
	if (error)
		goto failure;
#endif

	error = addrm_unknown_feature_attrs(fs_info, true);
	if (error)
		goto failure;

	fs_info->space_info_kobj = kobject_create_and_add("allocation",
						  fsid_kobj);
	if (!fs_info->space_info_kobj) {
		error = -ENOMEM;
		goto failure;
	}

	error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
	if (error)
		goto failure;

	return 0;
failure:
	btrfs_sysfs_remove_mounted(fs_info);
	return error;
}


/*
 * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 * values in superblock. Call after any changes to incompat/compat_ro flags
 */
void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
		u64 bit, enum btrfs_feature_set set)
{
	struct btrfs_fs_devices *fs_devs;
	struct kobject *fsid_kobj;
	u64 features;
	int ret;

	if (!fs_info)
		return;

	features = get_features(fs_info, set);
	ASSERT(bit & supported_feature_masks[set]);

	fs_devs = fs_info->fs_devices;
	fsid_kobj = &fs_devs->fsid_kobj;

	if (!fsid_kobj->state_initialized)
		return;

	/*
	 * FIXME: this is too heavy to update just one value, ideally we'd like
	 * to use sysfs_update_group but some refactoring is needed first.
	 */
	sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
	ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
}

int __init btrfs_init_sysfs(void)
{
	int ret;

	btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
	if (!btrfs_kset)
		return -ENOMEM;

	init_feature_attrs();
	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
	if (ret)
		goto out2;
	ret = sysfs_merge_group(&btrfs_kset->kobj,
				&btrfs_static_feature_attr_group);
	if (ret)
		goto out_remove_group;

#ifdef CONFIG_BTRFS_DEBUG
	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
	if (ret)
		goto out2;
#endif

	return 0;

out_remove_group:
	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
out2:
	kset_unregister(btrfs_kset);

	return ret;
}

void __cold btrfs_exit_sysfs(void)
{
	sysfs_unmerge_group(&btrfs_kset->kobj,
			    &btrfs_static_feature_attr_group);
	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
	kset_unregister(btrfs_kset);
}