summaryrefslogtreecommitdiff
path: root/libbcachefs.c
blob: 238cca9986b733464cb0cf2483fd114bf4a60810 (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
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#include <uuid/uuid.h>

#include "libbcachefs/bcachefs_format.h"
#include "libbcachefs/checksum.h"
#include "crypto.h"
#include "libbcachefs.h"
#include "libbcachefs/opts.h"
#include "libbcachefs/super-io.h"

#define NSEC_PER_SEC	1000000000L

#define BCH_MIN_NR_NBUCKETS	(1 << 10)

/* minimum size filesystem we can create, given a bucket size: */
static u64 min_size(unsigned bucket_size)
{
	return BCH_MIN_NR_NBUCKETS * bucket_size;
}

static void init_layout(struct bch_sb_layout *l, unsigned block_size,
			u64 start, u64 end)
{
	unsigned sb_size;
	u64 backup; /* offset of 2nd sb */

	memset(l, 0, sizeof(*l));

	if (start != BCH_SB_SECTOR)
		start = round_up(start, block_size);
	end = round_down(end, block_size);

	if (start >= end)
		die("insufficient space for superblocks");

	/*
	 * Create two superblocks in the allowed range: reserve a maximum of 64k
	 */
	sb_size = min_t(u64, 128, end - start / 2);

	backup = start + sb_size;
	backup = round_up(backup, block_size);

	backup = min(backup, end);

	sb_size = min(end - backup, backup- start);
	sb_size = rounddown_pow_of_two(sb_size);

	if (sb_size < 8)
		die("insufficient space for superblocks");

	l->magic		= BCACHE_MAGIC;
	l->layout_type		= 0;
	l->nr_superblocks	= 2;
	l->sb_max_size_bits	= ilog2(sb_size);
	l->sb_offset[0]		= cpu_to_le64(start);
	l->sb_offset[1]		= cpu_to_le64(backup);
}

void bch2_pick_bucket_size(struct format_opts opts, struct dev_opts *dev)
{
	if (!dev->sb_offset) {
		dev->sb_offset	= BCH_SB_SECTOR;
		dev->sb_end	= BCH_SB_SECTOR + 256;
	}

	if (!dev->size)
		dev->size = get_size(dev->path, dev->fd) >> 9;

	if (!dev->bucket_size) {
		if (dev->size < min_size(opts.block_size))
			die("cannot format %s, too small (%llu sectors, min %llu)",
			    dev->path, dev->size, min_size(opts.block_size));

		/* Bucket size must be >= block size: */
		dev->bucket_size = opts.block_size;

		/* Bucket size must be >= btree node size: */
		dev->bucket_size = max(dev->bucket_size, opts.btree_node_size);

		/* Want a bucket size of at least 128k, if possible: */
		dev->bucket_size = max(dev->bucket_size, 256U);

		if (dev->size >= min_size(dev->bucket_size)) {
			unsigned scale = max(1,
					     ilog2(dev->size / min_size(dev->bucket_size)) / 4);

			scale = rounddown_pow_of_two(scale);

			/* max bucket size 1 mb */
			dev->bucket_size = min(dev->bucket_size * scale, 1U << 11);
		} else {
			do {
				dev->bucket_size /= 2;
			} while (dev->size < min_size(dev->bucket_size));
		}
	}

	dev->nbuckets	= dev->size / dev->bucket_size;

	if (dev->bucket_size < opts.block_size)
		die("Bucket size cannot be smaller than block size");

	if (dev->bucket_size < opts.btree_node_size)
		die("Bucket size cannot be smaller than btree node size");

	if (dev->nbuckets < BCH_MIN_NR_NBUCKETS)
		die("Not enough buckets: %llu, need %u (bucket size %u)",
		    dev->nbuckets, BCH_MIN_NR_NBUCKETS, dev->bucket_size);

}

struct bch_sb *bch2_format(struct format_opts opts,
			   struct dev_opts *devs, size_t nr_devs)
{
	struct bch_sb *sb;
	struct dev_opts *i;
	struct bch_sb_field_members *mi;
	unsigned u64s;

	/* calculate block size: */
	if (!opts.block_size)
		for (i = devs; i < devs + nr_devs; i++)
			opts.block_size = max(opts.block_size,
					      get_blocksize(i->path, i->fd));

	/* calculate bucket sizes: */
	for (i = devs; i < devs + nr_devs; i++)
		bch2_pick_bucket_size(opts, i);

	/* calculate btree node size: */
	if (!opts.btree_node_size) {
		/* 256k default btree node size */
		opts.btree_node_size = 512;

		for (i = devs; i < devs + nr_devs; i++)
			opts.btree_node_size =
				min(opts.btree_node_size, i->bucket_size);
	}

	if (!is_power_of_2(opts.block_size))
		die("block size must be power of 2");

	if (!is_power_of_2(opts.btree_node_size))
		die("btree node size must be power of 2");

	if (uuid_is_null(opts.uuid.b))
		uuid_generate(opts.uuid.b);

	sb = calloc(1, sizeof(*sb) +
		    sizeof(struct bch_sb_field_members) +
		    sizeof(struct bch_member) * nr_devs +
		    sizeof(struct bch_sb_field_crypt));

	sb->version	= cpu_to_le64(BCH_SB_VERSION_MAX);
	sb->magic	= BCACHE_MAGIC;
	sb->block_size	= cpu_to_le16(opts.block_size);
	sb->user_uuid	= opts.uuid;
	sb->nr_devices	= nr_devs;

	uuid_generate(sb->uuid.b);

	if (opts.label)
		strncpy((char *) sb->label, opts.label, sizeof(sb->label));

	SET_BCH_SB_CSUM_TYPE(sb,		opts.meta_csum_type);
	SET_BCH_SB_META_CSUM_TYPE(sb,		opts.meta_csum_type);
	SET_BCH_SB_DATA_CSUM_TYPE(sb,		opts.data_csum_type);
	SET_BCH_SB_COMPRESSION_TYPE(sb,		opts.compression_type);

	SET_BCH_SB_BTREE_NODE_SIZE(sb,		opts.btree_node_size);
	SET_BCH_SB_GC_RESERVE(sb,		8);
	SET_BCH_SB_META_REPLICAS_WANT(sb,	opts.meta_replicas);
	SET_BCH_SB_META_REPLICAS_REQ(sb,	opts.meta_replicas_required);
	SET_BCH_SB_DATA_REPLICAS_WANT(sb,	opts.data_replicas);
	SET_BCH_SB_DATA_REPLICAS_REQ(sb,	opts.data_replicas_required);
	SET_BCH_SB_ERROR_ACTION(sb,		opts.on_error_action);
	SET_BCH_SB_STR_HASH_TYPE(sb,		BCH_STR_HASH_SIPHASH);
	SET_BCH_SB_ENCODED_EXTENT_MAX_BITS(sb,	ilog2(opts.encoded_extent_max));

	SET_BCH_SB_POSIX_ACL(sb,		1);

	struct timespec now;
	if (clock_gettime(CLOCK_REALTIME, &now))
		die("error getting current time: %m");

	sb->time_base_lo	= cpu_to_le64(now.tv_sec * NSEC_PER_SEC + now.tv_nsec);
	sb->time_precision	= cpu_to_le32(1);

	if (opts.encrypted) {
		struct bch_sb_field_crypt *crypt = vstruct_end(sb);

		u64s = sizeof(struct bch_sb_field_crypt) / sizeof(u64);

		le32_add_cpu(&sb->u64s, u64s);
		crypt->field.u64s = cpu_to_le32(u64s);
		crypt->field.type = BCH_SB_FIELD_crypt;

		bch_sb_crypt_init(sb, crypt, opts.passphrase);
		SET_BCH_SB_ENCRYPTION_TYPE(sb, 1);
	}

	mi = vstruct_end(sb);
	u64s = (sizeof(struct bch_sb_field_members) +
		sizeof(struct bch_member) * nr_devs) / sizeof(u64);

	le32_add_cpu(&sb->u64s, u64s);
	mi->field.u64s = cpu_to_le32(u64s);
	mi->field.type = BCH_SB_FIELD_members;

	for (i = devs; i < devs + nr_devs; i++) {
		struct bch_member *m = mi->members + (i - devs);

		uuid_generate(m->uuid.b);
		m->nbuckets	= cpu_to_le64(i->nbuckets);
		m->first_bucket	= 0;
		m->bucket_size	= cpu_to_le16(i->bucket_size);

		SET_BCH_MEMBER_TIER(m,		i->tier);
		SET_BCH_MEMBER_REPLACEMENT(m,	CACHE_REPLACEMENT_LRU);
		SET_BCH_MEMBER_DISCARD(m,	i->discard);
		SET_BCH_MEMBER_DATA_ALLOWED(m,	i->data_allowed);
	}

	for (i = devs; i < devs + nr_devs; i++) {
		sb->dev_idx = i - devs;

		init_layout(&sb->layout, opts.block_size,
			    i->sb_offset, i->sb_end);

		if (i->sb_offset == BCH_SB_SECTOR) {
			/* Zero start of disk */
			static const char zeroes[BCH_SB_SECTOR << 9];

			xpwrite(i->fd, zeroes, BCH_SB_SECTOR << 9, 0);
		}

		bch2_super_write(i->fd, sb);
		close(i->fd);
	}

	return sb;
}

void bch2_super_write(int fd, struct bch_sb *sb)
{
	struct nonce nonce = { 0 };

	unsigned i;
	for (i = 0; i < sb->layout.nr_superblocks; i++) {
		sb->offset = sb->layout.sb_offset[i];

		if (sb->offset == BCH_SB_SECTOR) {
			/* Write backup layout */
			xpwrite(fd, &sb->layout, sizeof(sb->layout),
				BCH_SB_LAYOUT_SECTOR << 9);
		}

		sb->csum = csum_vstruct(NULL, BCH_SB_CSUM_TYPE(sb), nonce, sb);
		xpwrite(fd, sb, vstruct_bytes(sb),
			le64_to_cpu(sb->offset) << 9);
	}

	fsync(fd);
}

struct bch_sb *__bch2_super_read(int fd, u64 sector)
{
	struct bch_sb sb, *ret;

	xpread(fd, &sb, sizeof(sb), sector << 9);

	if (memcmp(&sb.magic, &BCACHE_MAGIC, sizeof(sb.magic)))
		die("not a bcachefs superblock");

	size_t bytes = vstruct_bytes(&sb);

	ret = malloc(bytes);

	xpread(fd, ret, bytes, sector << 9);

	return ret;
}

static unsigned get_dev_has_data(struct bch_sb *sb, unsigned dev)
{
	struct bch_sb_field_replicas *replicas;
	struct bch_replicas_entry *r;
	unsigned i, data_has = 0;

	replicas = bch2_sb_get_replicas(sb);

	if (replicas)
		for_each_replicas_entry(replicas, r)
			for (i = 0; i < r->nr; i++)
				if (r->devs[i] == dev)
					data_has |= 1 << r->data_type;

	return data_has;
}

/* superblock printing: */

static void bch2_sb_print_layout(struct bch_sb *sb, enum units units)
{
	struct bch_sb_layout *l = &sb->layout;
	unsigned i;

	printf("  type:				%u\n"
	       "  superblock max size:		%s\n"
	       "  nr superblocks:		%u\n"
	       "  Offsets:			",
	       l->layout_type,
	       pr_units(1 << l->sb_max_size_bits, units),
	       l->nr_superblocks);

	for (i = 0; i < l->nr_superblocks; i++) {
		if (i)
			printf(", ");
		printf("%llu", le64_to_cpu(l->sb_offset[i]));
	}
	putchar('\n');
}

static void bch2_sb_print_journal(struct bch_sb *sb, struct bch_sb_field *f,
				  enum units units)
{
	struct bch_sb_field_journal *journal = field_to_type(f, journal);
	unsigned i, nr = bch2_nr_journal_buckets(journal);

	printf("  Buckets:			");
	for (i = 0; i < nr; i++) {
		if (i)
			putchar(' ');
		printf("%llu", le64_to_cpu(journal->buckets[i]));
	}
	putchar('\n');
}

static void bch2_sb_print_members(struct bch_sb *sb, struct bch_sb_field *f,
				  enum units units)
{
	struct bch_sb_field_members *mi = field_to_type(f, members);
	unsigned i;

	for (i = 0; i < sb->nr_devices; i++) {
		struct bch_member *m = mi->members + i;
		time_t last_mount = le64_to_cpu(m->last_mount);
		char member_uuid_str[40];
		char data_allowed_str[100];
		char data_has_str[100];

		if (!bch2_member_exists(m))
			continue;

		uuid_unparse(m->uuid.b, member_uuid_str);
		bch2_scnprint_flag_list(data_allowed_str,
					sizeof(data_allowed_str),
					bch2_data_types,
					BCH_MEMBER_DATA_ALLOWED(m));
		if (!data_allowed_str[0])
			strcpy(data_allowed_str, "(none)");

		bch2_scnprint_flag_list(data_has_str,
					sizeof(data_has_str),
					bch2_data_types,
					get_dev_has_data(sb, i));
		if (!data_has_str[0])
			strcpy(data_has_str, "(none)");

		printf("  Device %u:\n"
		       "    UUID:			%s\n"
		       "    Size:			%s\n"
		       "    Bucket size:		%s\n"
		       "    First bucket:		%u\n"
		       "    Buckets:			%llu\n"
		       "    Last mount:			%s\n"
		       "    State:			%s\n"
		       "    Tier:			%llu\n"
		       "    Data allowed:		%s\n"

		       "    Has data:			%s\n"

		       "    Replacement policy:		%s\n"
		       "    Discard:			%llu\n",
		       i, member_uuid_str,
		       pr_units(le16_to_cpu(m->bucket_size) *
				le64_to_cpu(m->nbuckets), units),
		       pr_units(le16_to_cpu(m->bucket_size), units),
		       le16_to_cpu(m->first_bucket),
		       le64_to_cpu(m->nbuckets),
		       last_mount ? ctime(&last_mount) : "(never)",

		       BCH_MEMBER_STATE(m) < BCH_MEMBER_STATE_NR
		       ? bch2_dev_state[BCH_MEMBER_STATE(m)]
		       : "unknown",

		       BCH_MEMBER_TIER(m),
		       data_allowed_str,
		       data_has_str,

		       BCH_MEMBER_REPLACEMENT(m) < CACHE_REPLACEMENT_NR
		       ? bch2_cache_replacement_policies[BCH_MEMBER_REPLACEMENT(m)]
		       : "unknown",

		       BCH_MEMBER_DISCARD(m));
	}
}

static void bch2_sb_print_crypt(struct bch_sb *sb, struct bch_sb_field *f,
				enum units units)
{
	struct bch_sb_field_crypt *crypt = field_to_type(f, crypt);

	printf("  KFD:			%llu\n"
	       "  scrypt n:		%llu\n"
	       "  scrypt r:		%llu\n"
	       "  scrypt p:		%llu\n",
	       BCH_CRYPT_KDF_TYPE(crypt),
	       BCH_KDF_SCRYPT_N(crypt),
	       BCH_KDF_SCRYPT_R(crypt),
	       BCH_KDF_SCRYPT_P(crypt));
}

static void bch2_sb_print_replicas(struct bch_sb *sb, struct bch_sb_field *f,
				   enum units units)
{
	struct bch_sb_field_replicas *replicas = field_to_type(f, replicas);
	struct bch_replicas_entry *e;
	unsigned i;

	for_each_replicas_entry(replicas, e) {
		printf_pad(32, "  %s:", bch2_data_types[e->data_type]);

		putchar('[');
		for (i = 0; i < e->nr; i++) {
			if (i)
				putchar(' ');
			printf("%u", e->devs[i]);
		}
		printf("]\n");
	}
}

static void bch2_sb_print_quota(struct bch_sb *sb, struct bch_sb_field *f,
				enum units units)
{
}

static void bch2_sb_print_disk_groups(struct bch_sb *sb, struct bch_sb_field *f,
				      enum units units)
{
}

typedef void (*sb_field_print_fn)(struct bch_sb *, struct bch_sb_field *, enum units);

struct bch_sb_field_ops {
	sb_field_print_fn	print;
};

static const struct bch_sb_field_ops bch2_sb_field_ops[] = {
#define x(f, nr)					\
	[BCH_SB_FIELD_##f] = {				\
		.print	= bch2_sb_print_##f,		\
	},
	BCH_SB_FIELDS()
#undef x
};

static inline void bch2_sb_field_print(struct bch_sb *sb,
				       struct bch_sb_field *f,
				       enum units units)
{
	unsigned type = le32_to_cpu(f->type);

	if (type < BCH_SB_FIELD_NR)
		bch2_sb_field_ops[type].print(sb, f, units);
	else
		printf("(unknown field %u)\n", type);
}

void bch2_sb_print(struct bch_sb *sb, bool print_layout,
		   unsigned fields, enum units units)
{
	struct bch_sb_field_members *mi;
	char user_uuid_str[40], internal_uuid_str[40];
	char fields_have_str[200];
	char label[BCH_SB_LABEL_SIZE + 1];
	struct bch_sb_field *f;
	u64 fields_have = 0;
	unsigned nr_devices = 0;

	memset(label, 0, sizeof(label));
	memcpy(label, sb->label, sizeof(sb->label));
	uuid_unparse(sb->user_uuid.b, user_uuid_str);
	uuid_unparse(sb->uuid.b, internal_uuid_str);

	mi = bch2_sb_get_members(sb);
	if (mi) {
		struct bch_member *m;

		for (m = mi->members;
		     m < mi->members + sb->nr_devices;
		     m++)
			nr_devices += bch2_member_exists(m);
	}

	vstruct_for_each(sb, f)
		fields_have |= 1 << le32_to_cpu(f->type);
	bch2_scnprint_flag_list(fields_have_str, sizeof(fields_have_str),
				bch2_sb_fields, fields_have);

	printf("External UUID:			%s\n"
	       "Internal UUID:			%s\n"
	       "Label:				%s\n"
	       "Version:			%llu\n"
	       "Block_size:			%s\n"
	       "Btree node size:		%s\n"
	       "Error action:			%s\n"
	       "Clean:				%llu\n"

	       "Metadata replicas:		%llu\n"
	       "Data replicas:			%llu\n"

	       "Metadata checksum type:		%s (%llu)\n"
	       "Data checksum type:		%s (%llu)\n"
	       "Compression type:		%s (%llu)\n"

	       "String hash type:		%s (%llu)\n"
	       "32 bit inodes:			%llu\n"
	       "GC reserve percentage:		%llu%%\n"
	       "Root reserve percentage:	%llu%%\n"

	       "Devices:			%u live, %u total\n"
	       "Sections:			%s\n"
	       "Superblock size:		%llu\n",
	       user_uuid_str,
	       internal_uuid_str,
	       label,
	       le64_to_cpu(sb->version),
	       pr_units(le16_to_cpu(sb->block_size), units),
	       pr_units(BCH_SB_BTREE_NODE_SIZE(sb), units),

	       BCH_SB_ERROR_ACTION(sb) < BCH_NR_ERROR_ACTIONS
	       ? bch2_error_actions[BCH_SB_ERROR_ACTION(sb)]
	       : "unknown",

	       BCH_SB_CLEAN(sb),

	       BCH_SB_META_REPLICAS_WANT(sb),
	       BCH_SB_DATA_REPLICAS_WANT(sb),

	       BCH_SB_META_CSUM_TYPE(sb) < BCH_CSUM_OPT_NR
	       ? bch2_csum_types[BCH_SB_META_CSUM_TYPE(sb)]
	       : "unknown",
	       BCH_SB_META_CSUM_TYPE(sb),

	       BCH_SB_DATA_CSUM_TYPE(sb) < BCH_CSUM_OPT_NR
	       ? bch2_csum_types[BCH_SB_DATA_CSUM_TYPE(sb)]
	       : "unknown",
	       BCH_SB_DATA_CSUM_TYPE(sb),

	       BCH_SB_COMPRESSION_TYPE(sb) < BCH_COMPRESSION_OPT_NR
	       ? bch2_compression_types[BCH_SB_COMPRESSION_TYPE(sb)]
	       : "unknown",
	       BCH_SB_COMPRESSION_TYPE(sb),

	       BCH_SB_STR_HASH_TYPE(sb) < BCH_STR_HASH_NR
	       ? bch2_str_hash_types[BCH_SB_STR_HASH_TYPE(sb)]
	       : "unknown",
	       BCH_SB_STR_HASH_TYPE(sb),

	       BCH_SB_INODE_32BIT(sb),
	       BCH_SB_GC_RESERVE(sb),
	       BCH_SB_ROOT_RESERVE(sb),

	       nr_devices, sb->nr_devices,
	       fields_have_str,
	       vstruct_bytes(sb));

	if (print_layout) {
		printf("\n"
		       "Layout:\n");
		bch2_sb_print_layout(sb, units);
	}

	vstruct_for_each(sb, f) {
		unsigned type = le32_to_cpu(f->type);
		char name[60];

		if (!(fields & (1 << type)))
			continue;

		if (type < BCH_SB_FIELD_NR) {
			scnprintf(name, sizeof(name), "%s", bch2_sb_fields[type]);
			name[0] = toupper(name[0]);
		} else {
			scnprintf(name, sizeof(name), "(unknown field %u)", type);
		}

		printf("\n%s (size %llu):\n", name, vstruct_bytes(f));
		if (type < BCH_SB_FIELD_NR)
			bch2_sb_field_print(sb, f, units);
	}
}

/* ioctl interface: */

/* Global control device: */
int bcachectl_open(void)
{
	return xopen("/dev/bcachefs-ctl", O_RDWR);
}

/* Filesystem handles (ioctl, sysfs dir): */

#define SYSFS_BASE "/sys/fs/bcachefs/"

void bcache_fs_close(struct bchfs_handle fs)
{
	close(fs.ioctl_fd);
	close(fs.sysfs_fd);
}

struct bchfs_handle bcache_fs_open(const char *path)
{
	struct bchfs_handle ret;

	if (!uuid_parse(path, ret.uuid.b)) {
		/* It's a UUID, look it up in sysfs: */
		char *sysfs = mprintf("%s%s", SYSFS_BASE, path);
		ret.sysfs_fd = xopen(sysfs, O_RDONLY);

		char *minor = read_file_str(ret.sysfs_fd, "minor");
		char *ctl = mprintf("/dev/bcachefs%s-ctl", minor);
		ret.ioctl_fd = xopen(ctl, O_RDWR);

		free(sysfs);
		free(minor);
		free(ctl);
	} else {
		/* It's a path: */
		ret.ioctl_fd = xopen(path, O_RDONLY);

		struct bch_ioctl_query_uuid uuid;
		xioctl(ret.ioctl_fd, BCH_IOCTL_QUERY_UUID, &uuid);

		ret.uuid = uuid.uuid;

		char uuid_str[40];
		uuid_unparse(uuid.uuid.b, uuid_str);

		char *sysfs = mprintf("%s%s", SYSFS_BASE, uuid_str);
		ret.sysfs_fd = xopen(sysfs, O_RDONLY);
		free(sysfs);
	}

	return ret;
}