summaryrefslogtreecommitdiff
path: root/fs/btrfs/volumes.h
blob: 9cc374864a79fab336c2638121f879ec7ddc9c7d (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
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 */

#ifndef BTRFS_VOLUMES_H
#define BTRFS_VOLUMES_H

#include <linux/sort.h>
#include <linux/btrfs.h>
#include "async-thread.h"
#include "messages.h"
#include "tree-checker.h"
#include "rcu-string.h"

#define BTRFS_MAX_DATA_CHUNK_SIZE	(10ULL * SZ_1G)

extern struct mutex uuid_mutex;

#define BTRFS_STRIPE_LEN		SZ_64K
#define BTRFS_STRIPE_LEN_SHIFT		(16)
#define BTRFS_STRIPE_LEN_MASK		(BTRFS_STRIPE_LEN - 1)

static_assert(const_ilog2(BTRFS_STRIPE_LEN) == BTRFS_STRIPE_LEN_SHIFT);

/* Used by sanity check for btrfs_raid_types. */
#define const_ffs(n) (__builtin_ctzll(n) + 1)

/*
 * The conversion from BTRFS_BLOCK_GROUP_* bits to btrfs_raid_type requires
 * RAID0 always to be the lowest profile bit.
 * Although it's part of on-disk format and should never change, do extra
 * compile-time sanity checks.
 */
static_assert(const_ffs(BTRFS_BLOCK_GROUP_RAID0) <
	      const_ffs(BTRFS_BLOCK_GROUP_PROFILE_MASK & ~BTRFS_BLOCK_GROUP_RAID0));
static_assert(const_ilog2(BTRFS_BLOCK_GROUP_RAID0) >
	      ilog2(BTRFS_BLOCK_GROUP_TYPE_MASK));

/* ilog2() can handle both constants and variables */
#define BTRFS_BG_FLAG_TO_INDEX(profile)					\
	ilog2((profile) >> (ilog2(BTRFS_BLOCK_GROUP_RAID0) - 1))

enum btrfs_raid_types {
	/* SINGLE is the special one as it doesn't have on-disk bit. */
	BTRFS_RAID_SINGLE  = 0,

	BTRFS_RAID_RAID0   = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID0),
	BTRFS_RAID_RAID1   = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID1),
	BTRFS_RAID_DUP	   = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_DUP),
	BTRFS_RAID_RAID10  = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID10),
	BTRFS_RAID_RAID5   = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID5),
	BTRFS_RAID_RAID6   = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID6),
	BTRFS_RAID_RAID1C3 = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID1C3),
	BTRFS_RAID_RAID1C4 = BTRFS_BG_FLAG_TO_INDEX(BTRFS_BLOCK_GROUP_RAID1C4),

	BTRFS_NR_RAID_TYPES
};

/*
 * Use sequence counter to get consistent device stat data on
 * 32-bit processors.
 */
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
#include <linux/seqlock.h>
#define __BTRFS_NEED_DEVICE_DATA_ORDERED
#define btrfs_device_data_ordered_init(device)	\
	seqcount_init(&device->data_seqcount)
#else
#define btrfs_device_data_ordered_init(device) do { } while (0)
#endif

#define BTRFS_DEV_STATE_WRITEABLE	(0)
#define BTRFS_DEV_STATE_IN_FS_METADATA	(1)
#define BTRFS_DEV_STATE_MISSING		(2)
#define BTRFS_DEV_STATE_REPLACE_TGT	(3)
#define BTRFS_DEV_STATE_FLUSH_SENT	(4)
#define BTRFS_DEV_STATE_NO_READA	(5)

struct btrfs_zoned_device_info;

struct btrfs_device {
	struct list_head dev_list; /* device_list_mutex */
	struct list_head dev_alloc_list; /* chunk mutex */
	struct list_head post_commit_list; /* chunk mutex */
	struct btrfs_fs_devices *fs_devices;
	struct btrfs_fs_info *fs_info;

	struct rcu_string __rcu *name;

	u64 generation;

	struct bdev_handle *bdev_handle;
	struct block_device *bdev;

	struct btrfs_zoned_device_info *zone_info;

	/*
	 * Device's major-minor number. Must be set even if the device is not
	 * opened (bdev == NULL), unless the device is missing.
	 */
	dev_t devt;
	unsigned long dev_state;
	blk_status_t last_flush_error;

#ifdef __BTRFS_NEED_DEVICE_DATA_ORDERED
	seqcount_t data_seqcount;
#endif

	/* the internal btrfs device id */
	u64 devid;

	/* size of the device in memory */
	u64 total_bytes;

	/* size of the device on disk */
	u64 disk_total_bytes;

	/* bytes used */
	u64 bytes_used;

	/* optimal io alignment for this device */
	u32 io_align;

	/* optimal io width for this device */
	u32 io_width;
	/* type and info about this device */
	u64 type;

	/* minimal io size for this device */
	u32 sector_size;

	/* physical drive uuid (or lvm uuid) */
	u8 uuid[BTRFS_UUID_SIZE];

	/*
	 * size of the device on the current transaction
	 *
	 * This variant is update when committing the transaction,
	 * and protected by chunk mutex
	 */
	u64 commit_total_bytes;

	/* bytes used on the current transaction */
	u64 commit_bytes_used;

	/* Bio used for flushing device barriers */
	struct bio flush_bio;
	struct completion flush_wait;

	/* per-device scrub information */
	struct scrub_ctx *scrub_ctx;

	/* disk I/O failure stats. For detailed description refer to
	 * enum btrfs_dev_stat_values in ioctl.h */
	int dev_stats_valid;

	/* Counter to record the change of device stats */
	atomic_t dev_stats_ccnt;
	atomic_t dev_stat_values[BTRFS_DEV_STAT_VALUES_MAX];

	struct extent_io_tree alloc_state;

	struct completion kobj_unregister;
	/* For sysfs/FSID/devinfo/devid/ */
	struct kobject devid_kobj;

	/* Bandwidth limit for scrub, in bytes */
	u64 scrub_speed_max;
};

/*
 * Block group or device which contains an active swapfile. Used for preventing
 * unsafe operations while a swapfile is active.
 *
 * These are sorted on (ptr, inode) (note that a block group or device can
 * contain more than one swapfile). We compare the pointer values because we
 * don't actually care what the object is, we just need a quick check whether
 * the object exists in the rbtree.
 */
struct btrfs_swapfile_pin {
	struct rb_node node;
	void *ptr;
	struct inode *inode;
	/*
	 * If true, ptr points to a struct btrfs_block_group. Otherwise, ptr
	 * points to a struct btrfs_device.
	 */
	bool is_block_group;
	/*
	 * Only used when 'is_block_group' is true and it is the number of
	 * extents used by a swapfile for this block group ('ptr' field).
	 */
	int bg_extent_count;
};

/*
 * If we read those variants at the context of their own lock, we needn't
 * use the following helpers, reading them directly is safe.
 */
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
#define BTRFS_DEVICE_GETSET_FUNCS(name)					\
static inline u64							\
btrfs_device_get_##name(const struct btrfs_device *dev)			\
{									\
	u64 size;							\
	unsigned int seq;						\
									\
	do {								\
		seq = read_seqcount_begin(&dev->data_seqcount);		\
		size = dev->name;					\
	} while (read_seqcount_retry(&dev->data_seqcount, seq));	\
	return size;							\
}									\
									\
static inline void							\
btrfs_device_set_##name(struct btrfs_device *dev, u64 size)		\
{									\
	preempt_disable();						\
	write_seqcount_begin(&dev->data_seqcount);			\
	dev->name = size;						\
	write_seqcount_end(&dev->data_seqcount);			\
	preempt_enable();						\
}
#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
#define BTRFS_DEVICE_GETSET_FUNCS(name)					\
static inline u64							\
btrfs_device_get_##name(const struct btrfs_device *dev)			\
{									\
	u64 size;							\
									\
	preempt_disable();						\
	size = dev->name;						\
	preempt_enable();						\
	return size;							\
}									\
									\
static inline void							\
btrfs_device_set_##name(struct btrfs_device *dev, u64 size)		\
{									\
	preempt_disable();						\
	dev->name = size;						\
	preempt_enable();						\
}
#else
#define BTRFS_DEVICE_GETSET_FUNCS(name)					\
static inline u64							\
btrfs_device_get_##name(const struct btrfs_device *dev)			\
{									\
	return dev->name;						\
}									\
									\
static inline void							\
btrfs_device_set_##name(struct btrfs_device *dev, u64 size)		\
{									\
	dev->name = size;						\
}
#endif

BTRFS_DEVICE_GETSET_FUNCS(total_bytes);
BTRFS_DEVICE_GETSET_FUNCS(disk_total_bytes);
BTRFS_DEVICE_GETSET_FUNCS(bytes_used);

enum btrfs_chunk_allocation_policy {
	BTRFS_CHUNK_ALLOC_REGULAR,
	BTRFS_CHUNK_ALLOC_ZONED,
};

/*
 * Read policies for mirrored block group profiles, read picks the stripe based
 * on these policies.
 */
enum btrfs_read_policy {
	/* Use process PID to choose the stripe */
	BTRFS_READ_POLICY_PID,
	BTRFS_NR_READ_POLICY,
};

struct btrfs_fs_devices {
	u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */

	/*
	 * UUID written into the btree blocks:
	 *
	 * - If metadata_uuid != fsid then super block must have
	 *   BTRFS_FEATURE_INCOMPAT_METADATA_UUID flag set.
	 *
	 * - Following shall be true at all times:
	 *   - metadata_uuid == btrfs_header::fsid
	 *   - metadata_uuid == btrfs_dev_item::fsid
	 *
	 * - Relations between fsid and metadata_uuid in sb and fs_devices:
	 *   - Normal:
	 *       fs_devices->fsid == fs_devices->metadata_uuid == sb->fsid
	 *       sb->metadata_uuid == 0
	 *
	 *   - When the BTRFS_FEATURE_INCOMPAT_METADATA_UUID flag is set:
	 *       fs_devices->fsid == sb->fsid
	 *       fs_devices->metadata_uuid == sb->metadata_uuid
	 *
	 *   - When in-memory fs_devices->temp_fsid is true
	 *	 fs_devices->fsid = random
	 *	 fs_devices->metadata_uuid == sb->fsid
	 */
	u8 metadata_uuid[BTRFS_FSID_SIZE];

	struct list_head fs_list;

	/*
	 * Number of devices under this fsid including missing and
	 * replace-target device and excludes seed devices.
	 */
	u64 num_devices;

	/*
	 * The number of devices that successfully opened, including
	 * replace-target, excludes seed devices.
	 */
	u64 open_devices;

	/* The number of devices that are under the chunk allocation list. */
	u64 rw_devices;

	/* Count of missing devices under this fsid excluding seed device. */
	u64 missing_devices;
	u64 total_rw_bytes;

	/*
	 * Count of devices from btrfs_super_block::num_devices for this fsid,
	 * which includes the seed device, excludes the transient replace-target
	 * device.
	 */
	u64 total_devices;

	/* Highest generation number of seen devices */
	u64 latest_generation;

	/*
	 * The mount device or a device with highest generation after removal
	 * or replace.
	 */
	struct btrfs_device *latest_dev;

	/*
	 * All of the devices in the filesystem, protected by a mutex so we can
	 * safely walk it to write out the super blocks without worrying about
	 * adding/removing by the multi-device code. Scrubbing super block can
	 * kick off supers writing by holding this mutex lock.
	 */
	struct mutex device_list_mutex;

	/* List of all devices, protected by device_list_mutex */
	struct list_head devices;

	/* Devices which can satisfy space allocation. Protected by * chunk_mutex. */
	struct list_head alloc_list;

	struct list_head seed_list;

	/* Count fs-devices opened. */
	int opened;

	/* Set when we find or add a device that doesn't have the nonrot flag set. */
	bool rotating;
	/* Devices support TRIM/discard commands. */
	bool discardable;
	/* The filesystem is a seed filesystem. */
	bool seeding;
	/* The mount needs to use a randomly generated fsid. */
	bool temp_fsid;

	struct btrfs_fs_info *fs_info;
	/* sysfs kobjects */
	struct kobject fsid_kobj;
	struct kobject *devices_kobj;
	struct kobject *devinfo_kobj;
	struct completion kobj_unregister;

	enum btrfs_chunk_allocation_policy chunk_alloc_policy;

	/* Policy used to read the mirrored stripes. */
	enum btrfs_read_policy read_policy;
};

#define BTRFS_MAX_DEVS(info) ((BTRFS_MAX_ITEM_SIZE(info)	\
			- sizeof(struct btrfs_chunk))		\
			/ sizeof(struct btrfs_stripe) + 1)

#define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE	\
				- 2 * sizeof(struct btrfs_disk_key)	\
				- 2 * sizeof(struct btrfs_chunk))	\
				/ sizeof(struct btrfs_stripe) + 1)

struct btrfs_io_stripe {
	struct btrfs_device *dev;
	/* Block mapping. */
	u64 physical;
	u64 length;
	bool is_scrub;
	/* For the endio handler. */
	struct btrfs_io_context *bioc;
};

struct btrfs_discard_stripe {
	struct btrfs_device *dev;
	u64 physical;
	u64 length;
};

/*
 * Context for IO subsmission for device stripe.
 *
 * - Track the unfinished mirrors for mirror based profiles
 *   Mirror based profiles are SINGLE/DUP/RAID1/RAID10.
 *
 * - Contain the logical -> physical mapping info
 *   Used by submit_stripe_bio() for mapping logical bio
 *   into physical device address.
 *
 * - Contain device replace info
 *   Used by handle_ops_on_dev_replace() to copy logical bios
 *   into the new device.
 *
 * - Contain RAID56 full stripe logical bytenrs
 */
struct btrfs_io_context {
	refcount_t refs;
	struct btrfs_fs_info *fs_info;
	u64 map_type; /* get from map_lookup->type */
	struct bio *orig_bio;
	atomic_t error;
	u16 max_errors;

	u64 logical;
	u64 size;
	/* Raid stripe tree ordered entry. */
	struct list_head rst_ordered_entry;

	/*
	 * The total number of stripes, including the extra duplicated
	 * stripe for replace.
	 */
	u16 num_stripes;

	/*
	 * The mirror_num of this bioc.
	 *
	 * This is for reads which use 0 as mirror_num, thus we should return a
	 * valid mirror_num (>0) for the reader.
	 */
	u16 mirror_num;

	/*
	 * The following two members are for dev-replace case only.
	 *
	 * @replace_nr_stripes:	Number of duplicated stripes which need to be
	 *			written to replace target.
	 *			Should be <= 2 (2 for DUP, otherwise <= 1).
	 * @replace_stripe_src:	The array indicates where the duplicated stripes
	 *			are from.
	 *
	 * The @replace_stripe_src[] array is mostly for RAID56 cases.
	 * As non-RAID56 stripes share the same contents of the mapped range,
	 * thus no need to bother where the duplicated ones are from.
	 *
	 * But for RAID56 case, all stripes contain different contents, thus
	 * we need a way to know the mapping.
	 *
	 * There is an example for the two members, using a RAID5 write:
	 *
	 *   num_stripes:	4 (3 + 1 duplicated write)
	 *   stripes[0]:	dev = devid 1, physical = X
	 *   stripes[1]:	dev = devid 2, physical = Y
	 *   stripes[2]:	dev = devid 3, physical = Z
	 *   stripes[3]:	dev = devid 0, physical = Y
	 *
	 * replace_nr_stripes = 1
	 * replace_stripe_src = 1	<- Means stripes[1] is involved in replace.
	 *				   The duplicated stripe index would be
	 *				   (@num_stripes - 1).
	 *
	 * Note, that we can still have cases replace_nr_stripes = 2 for DUP.
	 * In that case, all stripes share the same content, thus we don't
	 * need to bother @replace_stripe_src value at all.
	 */
	u16 replace_nr_stripes;
	s16 replace_stripe_src;
	/*
	 * Logical bytenr of the full stripe start, only for RAID56 cases.
	 *
	 * When this value is set to other than (u64)-1, the stripes[] should
	 * follow this pattern:
	 *
	 * (real_stripes = num_stripes - replace_nr_stripes)
	 * (data_stripes = (is_raid6) ? (real_stripes - 2) : (real_stripes - 1))
	 *
	 * stripes[0]:			The first data stripe
	 * stripes[1]:			The second data stripe
	 * ...
	 * stripes[data_stripes - 1]:	The last data stripe
	 * stripes[data_stripes]:	The P stripe
	 * stripes[data_stripes + 1]:	The Q stripe (only for RAID6).
	 */
	u64 full_stripe_logical;
	struct btrfs_io_stripe stripes[];
};

struct btrfs_device_info {
	struct btrfs_device *dev;
	u64 dev_offset;
	u64 max_avail;
	u64 total_avail;
};

struct btrfs_raid_attr {
	u8 sub_stripes;		/* sub_stripes info for map */
	u8 dev_stripes;		/* stripes per dev */
	u8 devs_max;		/* max devs to use */
	u8 devs_min;		/* min devs needed */
	u8 tolerated_failures;	/* max tolerated fail devs */
	u8 devs_increment;	/* ndevs has to be a multiple of this */
	u8 ncopies;		/* how many copies to data has */
	u8 nparity;		/* number of stripes worth of bytes to store
				 * parity information */
	u8 mindev_error;	/* error code if min devs requisite is unmet */
	const char raid_name[8]; /* name of the raid */
	u64 bg_flag;		/* block group flag of the raid */
};

extern const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES];

struct map_lookup {
	u64 type;
	int io_align;
	int io_width;
	int num_stripes;
	int sub_stripes;
	int verified_stripes; /* For mount time dev extent verification */
	struct btrfs_io_stripe stripes[];
};

#define map_lookup_size(n) (sizeof(struct map_lookup) + \
			    (sizeof(struct btrfs_io_stripe) * (n)))

struct btrfs_balance_args;
struct btrfs_balance_progress;
struct btrfs_balance_control {
	struct btrfs_balance_args data;
	struct btrfs_balance_args meta;
	struct btrfs_balance_args sys;

	u64 flags;

	struct btrfs_balance_progress stat;
};

/*
 * Search for a given device by the set parameters
 */
struct btrfs_dev_lookup_args {
	u64 devid;
	u8 *uuid;
	u8 *fsid;
	bool missing;
};

/* We have to initialize to -1 because BTRFS_DEV_REPLACE_DEVID is 0 */
#define BTRFS_DEV_LOOKUP_ARGS_INIT { .devid = (u64)-1 }

#define BTRFS_DEV_LOOKUP_ARGS(name) \
	struct btrfs_dev_lookup_args name = BTRFS_DEV_LOOKUP_ARGS_INIT

enum btrfs_map_op {
	BTRFS_MAP_READ,
	BTRFS_MAP_WRITE,
	BTRFS_MAP_GET_READ_MIRRORS,
};

static inline enum btrfs_map_op btrfs_op(struct bio *bio)
{
	switch (bio_op(bio)) {
	case REQ_OP_WRITE:
	case REQ_OP_ZONE_APPEND:
		return BTRFS_MAP_WRITE;
	default:
		WARN_ON_ONCE(1);
		fallthrough;
	case REQ_OP_READ:
		return BTRFS_MAP_READ;
	}
}

static inline unsigned long btrfs_chunk_item_size(int num_stripes)
{
	ASSERT(num_stripes);
	return sizeof(struct btrfs_chunk) +
		sizeof(struct btrfs_stripe) * (num_stripes - 1);
}

/*
 * Do the type safe converstion from stripe_nr to offset inside the chunk.
 *
 * @stripe_nr is u32, with left shift it can overflow u32 for chunks larger
 * than 4G.  This does the proper type cast to avoid overflow.
 */
static inline u64 btrfs_stripe_nr_to_offset(u32 stripe_nr)
{
	return (u64)stripe_nr << BTRFS_STRIPE_LEN_SHIFT;
}

void btrfs_get_bioc(struct btrfs_io_context *bioc);
void btrfs_put_bioc(struct btrfs_io_context *bioc);
int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
		    u64 logical, u64 *length,
		    struct btrfs_io_context **bioc_ret,
		    struct btrfs_io_stripe *smap, int *mirror_num_ret);
int btrfs_map_repair_block(struct btrfs_fs_info *fs_info,
			   struct btrfs_io_stripe *smap, u64 logical,
			   u32 length, int mirror_num);
struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
					       u64 logical, u64 *length_ret,
					       u32 *num_stripes);
int btrfs_read_sys_array(struct btrfs_fs_info *fs_info);
int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info);
struct btrfs_block_group *btrfs_create_chunk(struct btrfs_trans_handle *trans,
					    u64 type);
void btrfs_mapping_tree_free(struct extent_map_tree *tree);
int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
		       blk_mode_t flags, void *holder);
struct btrfs_device *btrfs_scan_one_device(const char *path, blk_mode_t flags,
					   bool mount_arg_dev);
int btrfs_forget_devices(dev_t devt);
void btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices);
void btrfs_assign_next_active_device(struct btrfs_device *device,
				     struct btrfs_device *this_dev);
struct btrfs_device *btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info,
						  u64 devid,
						  const char *devpath);
int btrfs_get_dev_args_from_path(struct btrfs_fs_info *fs_info,
				 struct btrfs_dev_lookup_args *args,
				 const char *path);
struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
					const u64 *devid, const u8 *uuid,
					const char *path);
void btrfs_put_dev_args_from_path(struct btrfs_dev_lookup_args *args);
int btrfs_rm_device(struct btrfs_fs_info *fs_info,
		    struct btrfs_dev_lookup_args *args,
		    struct bdev_handle **bdev_handle);
void __exit btrfs_cleanup_fs_uuids(void);
int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len);
int btrfs_grow_device(struct btrfs_trans_handle *trans,
		      struct btrfs_device *device, u64 new_size);
struct btrfs_device *btrfs_find_device(const struct btrfs_fs_devices *fs_devices,
				       const struct btrfs_dev_lookup_args *args);
int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *path);
int btrfs_balance(struct btrfs_fs_info *fs_info,
		  struct btrfs_balance_control *bctl,
		  struct btrfs_ioctl_balance_args *bargs);
void btrfs_describe_block_groups(u64 flags, char *buf, u32 size_buf);
int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info);
int btrfs_recover_balance(struct btrfs_fs_info *fs_info);
int btrfs_pause_balance(struct btrfs_fs_info *fs_info);
int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset);
int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info);
int btrfs_uuid_scan_kthread(void *data);
bool btrfs_chunk_writeable(struct btrfs_fs_info *fs_info, u64 chunk_offset);
void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index);
int btrfs_get_dev_stats(struct btrfs_fs_info *fs_info,
			struct btrfs_ioctl_get_dev_stats *stats);
int btrfs_init_devices_late(struct btrfs_fs_info *fs_info);
int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info);
int btrfs_run_dev_stats(struct btrfs_trans_handle *trans);
void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_device *srcdev);
void btrfs_rm_dev_replace_free_srcdev(struct btrfs_device *srcdev);
void btrfs_destroy_dev_replace_tgtdev(struct btrfs_device *tgtdev);
int btrfs_is_parity_mirror(struct btrfs_fs_info *fs_info,
			   u64 logical, u64 len);
unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
				    u64 logical);
u64 btrfs_calc_stripe_length(const struct extent_map *em);
int btrfs_nr_parity_stripes(u64 type);
int btrfs_chunk_alloc_add_chunk_item(struct btrfs_trans_handle *trans,
				     struct btrfs_block_group *bg);
int btrfs_remove_chunk(struct btrfs_trans_handle *trans, u64 chunk_offset);
struct extent_map *btrfs_get_chunk_map(struct btrfs_fs_info *fs_info,
				       u64 logical, u64 length);
void btrfs_release_disk_super(struct btrfs_super_block *super);

static inline void btrfs_dev_stat_inc(struct btrfs_device *dev,
				      int index)
{
	atomic_inc(dev->dev_stat_values + index);
	/*
	 * This memory barrier orders stores updating statistics before stores
	 * updating dev_stats_ccnt.
	 *
	 * It pairs with smp_rmb() in btrfs_run_dev_stats().
	 */
	smp_mb__before_atomic();
	atomic_inc(&dev->dev_stats_ccnt);
}

static inline int btrfs_dev_stat_read(struct btrfs_device *dev,
				      int index)
{
	return atomic_read(dev->dev_stat_values + index);
}

static inline int btrfs_dev_stat_read_and_reset(struct btrfs_device *dev,
						int index)
{
	int ret;

	ret = atomic_xchg(dev->dev_stat_values + index, 0);
	/*
	 * atomic_xchg implies a full memory barriers as per atomic_t.txt:
	 * - RMW operations that have a return value are fully ordered;
	 *
	 * This implicit memory barriers is paired with the smp_rmb in
	 * btrfs_run_dev_stats
	 */
	atomic_inc(&dev->dev_stats_ccnt);
	return ret;
}

static inline void btrfs_dev_stat_set(struct btrfs_device *dev,
				      int index, unsigned long val)
{
	atomic_set(dev->dev_stat_values + index, val);
	/*
	 * This memory barrier orders stores updating statistics before stores
	 * updating dev_stats_ccnt.
	 *
	 * It pairs with smp_rmb() in btrfs_run_dev_stats().
	 */
	smp_mb__before_atomic();
	atomic_inc(&dev->dev_stats_ccnt);
}

static inline const char *btrfs_dev_name(const struct btrfs_device *device)
{
	if (!device || test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
		return "<missing disk>";
	else
		return rcu_str_deref(device->name);
}

void btrfs_commit_device_sizes(struct btrfs_transaction *trans);

struct list_head * __attribute_const__ btrfs_get_fs_uuids(void);
bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,
					struct btrfs_device *failing_dev);
void btrfs_scratch_superblocks(struct btrfs_fs_info *fs_info,
			       struct block_device *bdev,
			       const char *device_path);

enum btrfs_raid_types __attribute_const__ btrfs_bg_flags_to_raid_index(u64 flags);
int btrfs_bg_type_to_factor(u64 flags);
const char *btrfs_bg_type_to_raid_name(u64 flags);
int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info);
bool btrfs_repair_one_zone(struct btrfs_fs_info *fs_info, u64 logical);

bool btrfs_pinned_by_swapfile(struct btrfs_fs_info *fs_info, void *ptr);
u8 *btrfs_sb_fsid_ptr(struct btrfs_super_block *sb);

#endif