summaryrefslogtreecommitdiffstats
path: root/fs/btrfs/fs.h
blob: a749367e5ae2a2b9090a44ec8c0dfc8536f92131 (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
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef BTRFS_FS_H
#define BTRFS_FS_H

#include <linux/fs.h>
#include <linux/btrfs_tree.h>
#include <linux/sizes.h>
#include "extent-io-tree.h"
#include "extent_map.h"
#include "async-thread.h"
#include "block-rsv.h"

#define BTRFS_MAX_EXTENT_SIZE SZ_128M

#define BTRFS_OLDEST_GENERATION	0ULL

#define BTRFS_EMPTY_DIR_SIZE 0

#define BTRFS_DIRTY_METADATA_THRESH		SZ_32M

#define BTRFS_SUPER_INFO_OFFSET			SZ_64K
#define BTRFS_SUPER_INFO_SIZE			4096
static_assert(sizeof(struct btrfs_super_block) == BTRFS_SUPER_INFO_SIZE);

/*
 * The reserved space at the beginning of each device.  It covers the primary
 * super block and leaves space for potential use by other tools like
 * bootloaders or to lower potential damage of accidental overwrite.
 */
#define BTRFS_DEVICE_RANGE_RESERVED			(SZ_1M)
/*
 * Runtime (in-memory) states of filesystem
 */
enum {
	/* Global indicator of serious filesystem errors */
	BTRFS_FS_STATE_ERROR,
	/*
	 * Filesystem is being remounted, allow to skip some operations, like
	 * defrag
	 */
	BTRFS_FS_STATE_REMOUNTING,
	/* Filesystem in RO mode */
	BTRFS_FS_STATE_RO,
	/* Track if a transaction abort has been reported on this filesystem */
	BTRFS_FS_STATE_TRANS_ABORTED,
	/*
	 * Bio operations should be blocked on this filesystem because a source
	 * or target device is being destroyed as part of a device replace
	 */
	BTRFS_FS_STATE_DEV_REPLACING,
	/* The btrfs_fs_info created for self-tests */
	BTRFS_FS_STATE_DUMMY_FS_INFO,

	BTRFS_FS_STATE_NO_CSUMS,

	/* Indicates there was an error cleaning up a log tree. */
	BTRFS_FS_STATE_LOG_CLEANUP_ERROR,

	BTRFS_FS_STATE_COUNT
};

enum {
	BTRFS_FS_CLOSING_START,
	BTRFS_FS_CLOSING_DONE,
	BTRFS_FS_LOG_RECOVERING,
	BTRFS_FS_OPEN,
	BTRFS_FS_QUOTA_ENABLED,
	BTRFS_FS_UPDATE_UUID_TREE_GEN,
	BTRFS_FS_CREATING_FREE_SPACE_TREE,
	BTRFS_FS_BTREE_ERR,
	BTRFS_FS_LOG1_ERR,
	BTRFS_FS_LOG2_ERR,
	BTRFS_FS_QUOTA_OVERRIDE,
	/* Used to record internally whether fs has been frozen */
	BTRFS_FS_FROZEN,
	/*
	 * Indicate that balance has been set up from the ioctl and is in the
	 * main phase. The fs_info::balance_ctl is initialized.
	 */
	BTRFS_FS_BALANCE_RUNNING,

	/*
	 * Indicate that relocation of a chunk has started, it's set per chunk
	 * and is toggled between chunks.
	 */
	BTRFS_FS_RELOC_RUNNING,

	/* Indicate that the cleaner thread is awake and doing something. */
	BTRFS_FS_CLEANER_RUNNING,

	/*
	 * The checksumming has an optimized version and is considered fast,
	 * so we don't need to offload checksums to workqueues.
	 */
	BTRFS_FS_CSUM_IMPL_FAST,

	/* Indicate that the discard workqueue can service discards. */
	BTRFS_FS_DISCARD_RUNNING,

	/* Indicate that we need to cleanup space cache v1 */
	BTRFS_FS_CLEANUP_SPACE_CACHE_V1,

	/* Indicate that we can't trust the free space tree for caching yet */
	BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED,

	/* Indicate whether there are any tree modification log users */
	BTRFS_FS_TREE_MOD_LOG_USERS,

	/* Indicate that we want the transaction kthread to commit right now. */
	BTRFS_FS_COMMIT_TRANS,

	/* Indicate we have half completed snapshot deletions pending. */
	BTRFS_FS_UNFINISHED_DROPS,

	/* Indicate we have to finish a zone to do next allocation. */
	BTRFS_FS_NEED_ZONE_FINISH,

	/* Indicate that we want to commit the transaction. */
	BTRFS_FS_NEED_TRANS_COMMIT,

#if BITS_PER_LONG == 32
	/* Indicate if we have error/warn message printed on 32bit systems */
	BTRFS_FS_32BIT_ERROR,
	BTRFS_FS_32BIT_WARN,
#endif
};

/*
 * Flags for mount options.
 *
 * Note: don't forget to add new options to btrfs_show_options()
 */
enum {
	BTRFS_MOUNT_NODATASUM			= (1UL << 0),
	BTRFS_MOUNT_NODATACOW			= (1UL << 1),
	BTRFS_MOUNT_NOBARRIER			= (1UL << 2),
	BTRFS_MOUNT_SSD				= (1UL << 3),
	BTRFS_MOUNT_DEGRADED			= (1UL << 4),
	BTRFS_MOUNT_COMPRESS			= (1UL << 5),
	BTRFS_MOUNT_NOTREELOG   		= (1UL << 6),
	BTRFS_MOUNT_FLUSHONCOMMIT		= (1UL << 7),
	BTRFS_MOUNT_SSD_SPREAD			= (1UL << 8),
	BTRFS_MOUNT_NOSSD			= (1UL << 9),
	BTRFS_MOUNT_DISCARD_SYNC		= (1UL << 10),
	BTRFS_MOUNT_FORCE_COMPRESS      	= (1UL << 11),
	BTRFS_MOUNT_SPACE_CACHE			= (1UL << 12),
	BTRFS_MOUNT_CLEAR_CACHE			= (1UL << 13),
	BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED	= (1UL << 14),
	BTRFS_MOUNT_ENOSPC_DEBUG		= (1UL << 15),
	BTRFS_MOUNT_AUTO_DEFRAG			= (1UL << 16),
	BTRFS_MOUNT_USEBACKUPROOT		= (1UL << 17),
	BTRFS_MOUNT_SKIP_BALANCE		= (1UL << 18),
	BTRFS_MOUNT_CHECK_INTEGRITY		= (1UL << 19),
	BTRFS_MOUNT_CHECK_INTEGRITY_DATA	= (1UL << 20),
	BTRFS_MOUNT_PANIC_ON_FATAL_ERROR	= (1UL << 21),
	BTRFS_MOUNT_RESCAN_UUID_TREE		= (1UL << 22),
	BTRFS_MOUNT_FRAGMENT_DATA		= (1UL << 23),
	BTRFS_MOUNT_FRAGMENT_METADATA		= (1UL << 24),
	BTRFS_MOUNT_FREE_SPACE_TREE		= (1UL << 25),
	BTRFS_MOUNT_NOLOGREPLAY			= (1UL << 26),
	BTRFS_MOUNT_REF_VERIFY			= (1UL << 27),
	BTRFS_MOUNT_DISCARD_ASYNC		= (1UL << 28),
	BTRFS_MOUNT_IGNOREBADROOTS		= (1UL << 29),
	BTRFS_MOUNT_IGNOREDATACSUMS		= (1UL << 30),
	BTRFS_MOUNT_NODISCARD			= (1UL << 31),
};

/*
 * Compat flags that we support.  If any incompat flags are set other than the
 * ones specified below then we will fail to mount
 */
#define BTRFS_FEATURE_COMPAT_SUPP		0ULL
#define BTRFS_FEATURE_COMPAT_SAFE_SET		0ULL
#define BTRFS_FEATURE_COMPAT_SAFE_CLEAR		0ULL

#define BTRFS_FEATURE_COMPAT_RO_SUPP			\
	(BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE |	\
	 BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE_VALID | \
	 BTRFS_FEATURE_COMPAT_RO_VERITY |		\
	 BTRFS_FEATURE_COMPAT_RO_BLOCK_GROUP_TREE)

#define BTRFS_FEATURE_COMPAT_RO_SAFE_SET	0ULL
#define BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR	0ULL

#ifdef CONFIG_BTRFS_DEBUG
/*
 * Extent tree v2 supported only with CONFIG_BTRFS_DEBUG
 */
#define BTRFS_FEATURE_INCOMPAT_SUPP			\
	(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |		\
	 BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |	\
	 BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |		\
	 BTRFS_FEATURE_INCOMPAT_BIG_METADATA |		\
	 BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO |		\
	 BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD |		\
	 BTRFS_FEATURE_INCOMPAT_RAID56 |		\
	 BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |		\
	 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |	\
	 BTRFS_FEATURE_INCOMPAT_NO_HOLES	|	\
	 BTRFS_FEATURE_INCOMPAT_METADATA_UUID	|	\
	 BTRFS_FEATURE_INCOMPAT_RAID1C34	|	\
	 BTRFS_FEATURE_INCOMPAT_ZONED		|	\
	 BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2)
#else
#define BTRFS_FEATURE_INCOMPAT_SUPP			\
	(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |		\
	 BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |	\
	 BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |		\
	 BTRFS_FEATURE_INCOMPAT_BIG_METADATA |		\
	 BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO |		\
	 BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD |		\
	 BTRFS_FEATURE_INCOMPAT_RAID56 |		\
	 BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |		\
	 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |	\
	 BTRFS_FEATURE_INCOMPAT_NO_HOLES	|	\
	 BTRFS_FEATURE_INCOMPAT_METADATA_UUID	|	\
	 BTRFS_FEATURE_INCOMPAT_RAID1C34	|	\
	 BTRFS_FEATURE_INCOMPAT_ZONED)
#endif

#define BTRFS_FEATURE_INCOMPAT_SAFE_SET			\
	(BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
#define BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR		0ULL

#define BTRFS_DEFAULT_COMMIT_INTERVAL	(30)
#define BTRFS_DEFAULT_MAX_INLINE	(2048)

struct btrfs_dev_replace {
	/* See #define above */
	u64 replace_state;
	/* Seconds since 1-Jan-1970 */
	time64_t time_started;
	/* Seconds since 1-Jan-1970 */
	time64_t time_stopped;
	atomic64_t num_write_errors;
	atomic64_t num_uncorrectable_read_errors;

	u64 cursor_left;
	u64 committed_cursor_left;
	u64 cursor_left_last_write_of_item;
	u64 cursor_right;

	/* See #define above */
	u64 cont_reading_from_srcdev_mode;

	int is_valid;
	int item_needs_writeback;
	struct btrfs_device *srcdev;
	struct btrfs_device *tgtdev;

	struct mutex lock_finishing_cancel_unmount;
	struct rw_semaphore rwsem;

	struct btrfs_scrub_progress scrub_progress;

	struct percpu_counter bio_counter;
	wait_queue_head_t replace_wait;
};

/*
 * Free clusters are used to claim free space in relatively large chunks,
 * allowing us to do less seeky writes. They are used for all metadata
 * allocations. In ssd_spread mode they are also used for data allocations.
 */
struct btrfs_free_cluster {
	spinlock_t lock;
	spinlock_t refill_lock;
	struct rb_root root;

	/* Largest extent in this cluster */
	u64 max_size;

	/* First extent starting offset */
	u64 window_start;

	/* We did a full search and couldn't create a cluster */
	bool fragmented;

	struct btrfs_block_group *block_group;
	/*
	 * When a cluster is allocated from a block group, we put the cluster
	 * onto a list in the block group so that it can be freed before the
	 * block group is freed.
	 */
	struct list_head block_group_list;
};

/* Discard control. */
/*
 * Async discard uses multiple lists to differentiate the discard filter
 * parameters.  Index 0 is for completely free block groups where we need to
 * ensure the entire block group is trimmed without being lossy.  Indices
 * afterwards represent monotonically decreasing discard filter sizes to
 * prioritize what should be discarded next.
 */
#define BTRFS_NR_DISCARD_LISTS		3
#define BTRFS_DISCARD_INDEX_UNUSED	0
#define BTRFS_DISCARD_INDEX_START	1

struct btrfs_discard_ctl {
	struct workqueue_struct *discard_workers;
	struct delayed_work work;
	spinlock_t lock;
	struct btrfs_block_group *block_group;
	struct list_head discard_list[BTRFS_NR_DISCARD_LISTS];
	u64 prev_discard;
	u64 prev_discard_time;
	atomic_t discardable_extents;
	atomic64_t discardable_bytes;
	u64 max_discard_size;
	u64 delay_ms;
	u32 iops_limit;
	u32 kbps_limit;
	u64 discard_extent_bytes;
	u64 discard_bitmap_bytes;
	atomic64_t discard_bytes_saved;
};

/*
 * Exclusive operations (device replace, resize, device add/remove, balance)
 */
enum btrfs_exclusive_operation {
	BTRFS_EXCLOP_NONE,
	BTRFS_EXCLOP_BALANCE_PAUSED,
	BTRFS_EXCLOP_BALANCE,
	BTRFS_EXCLOP_DEV_ADD,
	BTRFS_EXCLOP_DEV_REMOVE,
	BTRFS_EXCLOP_DEV_REPLACE,
	BTRFS_EXCLOP_RESIZE,
	BTRFS_EXCLOP_SWAP_ACTIVATE,
};

/* Store data about transaction commits, exported via sysfs. */
struct btrfs_commit_stats {
	/* Total number of commits */
	u64 commit_count;
	/* The maximum commit duration so far in ns */
	u64 max_commit_dur;
	/* The last commit duration in ns */
	u64 last_commit_dur;
	/* The total commit duration in ns */
	u64 total_commit_dur;
};

struct btrfs_fs_info {
	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
	unsigned long flags;
	struct btrfs_root *tree_root;
	struct btrfs_root *chunk_root;
	struct btrfs_root *dev_root;
	struct btrfs_root *fs_root;
	struct btrfs_root *quota_root;
	struct btrfs_root *uuid_root;
	struct btrfs_root *data_reloc_root;
	struct btrfs_root *block_group_root;

	/* The log root tree is a directory of all the other log roots */
	struct btrfs_root *log_root_tree;

	/* The tree that holds the global roots (csum, extent, etc) */
	rwlock_t global_root_lock;
	struct rb_root global_root_tree;

	spinlock_t fs_roots_radix_lock;
	struct radix_tree_root fs_roots_radix;

	/* Block group cache stuff */
	rwlock_t block_group_cache_lock;
	struct rb_root_cached block_group_cache_tree;

	/* Keep track of unallocated space */
	atomic64_t free_chunk_space;

	/* Track ranges which are used by log trees blocks/logged data extents */
	struct extent_io_tree excluded_extents;

	/* logical->physical extent mapping */
	struct extent_map_tree mapping_tree;

	/*
	 * Block reservation for extent, checksum, root tree and delayed dir
	 * index item.
	 */
	struct btrfs_block_rsv global_block_rsv;
	/* Block reservation for metadata operations */
	struct btrfs_block_rsv trans_block_rsv;
	/* Block reservation for chunk tree */
	struct btrfs_block_rsv chunk_block_rsv;
	/* Block reservation for delayed operations */
	struct btrfs_block_rsv delayed_block_rsv;
	/* Block reservation for delayed refs */
	struct btrfs_block_rsv delayed_refs_rsv;

	struct btrfs_block_rsv empty_block_rsv;

	u64 generation;
	u64 last_trans_committed;
	/*
	 * Generation of the last transaction used for block group relocation
	 * since the filesystem was last mounted (or 0 if none happened yet).
	 * Must be written and read while holding btrfs_fs_info::commit_root_sem.
	 */
	u64 last_reloc_trans;
	u64 avg_delayed_ref_runtime;

	/*
	 * This is updated to the current trans every time a full commit is
	 * required instead of the faster short fsync log commits
	 */
	u64 last_trans_log_full_commit;
	unsigned long mount_opt;

	unsigned long compress_type:4;
	unsigned int compress_level;
	u32 commit_interval;
	/*
	 * It is a suggestive number, the read side is safe even it gets a
	 * wrong number because we will write out the data into a regular
	 * extent. The write side(mount/remount) is under ->s_umount lock,
	 * so it is also safe.
	 */
	u64 max_inline;

	struct btrfs_transaction *running_transaction;
	wait_queue_head_t transaction_throttle;
	wait_queue_head_t transaction_wait;
	wait_queue_head_t transaction_blocked_wait;
	wait_queue_head_t async_submit_wait;

	/*
	 * Used to protect the incompat_flags, compat_flags, compat_ro_flags
	 * when they are updated.
	 *
	 * Because we do not clear the flags for ever, so we needn't use
	 * the lock on the read side.
	 *
	 * We also needn't use the lock when we mount the fs, because
	 * there is no other task which will update the flag.
	 */
	spinlock_t super_lock;
	struct btrfs_super_block *super_copy;
	struct btrfs_super_block *super_for_commit;
	struct super_block *sb;
	struct inode *btree_inode;
	struct mutex tree_log_mutex;
	struct mutex transaction_kthread_mutex;
	struct mutex cleaner_mutex;
	struct mutex chunk_mutex;

	/*
	 * This is taken to make sure we don't set block groups ro after the
	 * free space cache has been allocated on them.
	 */
	struct mutex ro_block_group_mutex;

	/*
	 * This is used during read/modify/write to make sure no two ios are
	 * trying to mod the same stripe at the same time.
	 */
	struct btrfs_stripe_hash_table *stripe_hash_table;

	/*
	 * This protects the ordered operations list only while we are
	 * processing all of the entries on it.  This way we make sure the
	 * commit code doesn't find the list temporarily empty because another
	 * function happens to be doing non-waiting preflush before jumping
	 * into the main commit.
	 */
	struct mutex ordered_operations_mutex;

	struct rw_semaphore commit_root_sem;

	struct rw_semaphore cleanup_work_sem;

	struct rw_semaphore subvol_sem;

	spinlock_t trans_lock;
	/*
	 * The reloc mutex goes with the trans lock, it is taken during commit
	 * to protect us from the relocation code.
	 */
	struct mutex reloc_mutex;

	struct list_head trans_list;
	struct list_head dead_roots;
	struct list_head caching_block_groups;

	spinlock_t delayed_iput_lock;
	struct list_head delayed_iputs;
	atomic_t nr_delayed_iputs;
	wait_queue_head_t delayed_iputs_wait;

	atomic64_t tree_mod_seq;

	/* This protects tree_mod_log and tree_mod_seq_list */
	rwlock_t tree_mod_log_lock;
	struct rb_root tree_mod_log;
	struct list_head tree_mod_seq_list;

	atomic_t async_delalloc_pages;

	/* This is used to protect the following list -- ordered_roots. */
	spinlock_t ordered_root_lock;

	/*
	 * All fs/file tree roots in which there are data=ordered extents
	 * pending writeback are added into this list.
	 *
	 * These can span multiple transactions and basically include every
	 * dirty data page that isn't from nodatacow.
	 */
	struct list_head ordered_roots;

	struct mutex delalloc_root_mutex;
	spinlock_t delalloc_root_lock;
	/* All fs/file tree roots that have delalloc inodes. */
	struct list_head delalloc_roots;

	/*
	 * There is a pool of worker threads for checksumming during writes and
	 * a pool for checksumming after reads.  This is because readers can
	 * run with FS locks held, and the writers may be waiting for those
	 * locks.  We don't want ordering in the pending list to cause
	 * deadlocks, and so the two are serviced separately.
	 *
	 * A third pool does submit_bio to avoid deadlocking with the other two.
	 */
	struct btrfs_workqueue *workers;
	struct btrfs_workqueue *hipri_workers;
	struct btrfs_workqueue *delalloc_workers;
	struct btrfs_workqueue *flush_workers;
	struct workqueue_struct *endio_workers;
	struct workqueue_struct *endio_meta_workers;
	struct workqueue_struct *rmw_workers;
	struct workqueue_struct *compressed_write_workers;
	struct btrfs_workqueue *endio_write_workers;
	struct btrfs_workqueue *endio_freespace_worker;
	struct btrfs_workqueue *caching_workers;

	/*
	 * Fixup workers take dirty pages that didn't properly go through the
	 * cow mechanism and make them safe to write.  It happens for the
	 * sys_munmap function call path.
	 */
	struct btrfs_workqueue *fixup_workers;
	struct btrfs_workqueue *delayed_workers;

	struct task_struct *transaction_kthread;
	struct task_struct *cleaner_kthread;
	u32 thread_pool_size;

	struct kobject *space_info_kobj;
	struct kobject *qgroups_kobj;
	struct kobject *discard_kobj;

	/* Used to keep from writing metadata until there is a nice batch */
	struct percpu_counter dirty_metadata_bytes;
	struct percpu_counter delalloc_bytes;
	struct percpu_counter ordered_bytes;
	s32 dirty_metadata_batch;
	s32 delalloc_batch;

	struct list_head dirty_cowonly_roots;

	struct btrfs_fs_devices *fs_devices;

	/*
	 * The space_info list is effectively read only after initial setup.
	 * It is populated at mount time and cleaned up after all block groups
	 * are removed.  RCU is used to protect it.
	 */
	struct list_head space_info;

	struct btrfs_space_info *data_sinfo;

	struct reloc_control *reloc_ctl;

	/* data_alloc_cluster is only used in ssd_spread mode */
	struct btrfs_free_cluster data_alloc_cluster;

	/* All metadata allocations go through this cluster. */
	struct btrfs_free_cluster meta_alloc_cluster;

	/* Auto defrag inodes go here. */
	spinlock_t defrag_inodes_lock;
	struct rb_root defrag_inodes;
	atomic_t defrag_running;

	/* Used to protect avail_{data, metadata, system}_alloc_bits */
	seqlock_t profiles_lock;
	/*
	 * These three are in extended format (availability of single chunks is
	 * denoted by BTRFS_AVAIL_ALLOC_BIT_SINGLE bit, other types are denoted
	 * by corresponding BTRFS_BLOCK_GROUP_* bits)
	 */
	u64 avail_data_alloc_bits;
	u64 avail_metadata_alloc_bits;
	u64 avail_system_alloc_bits;

	/* Balance state */
	spinlock_t balance_lock;
	struct mutex balance_mutex;
	atomic_t balance_pause_req;
	atomic_t balance_cancel_req;
	struct btrfs_balance_control *balance_ctl;
	wait_queue_head_t balance_wait_q;

	/* Cancellation requests for chunk relocation */
	atomic_t reloc_cancel_req;

	u32 data_chunk_allocations;
	u32 metadata_ratio;

	void *bdev_holder;

	/* Private scrub information */
	struct mutex scrub_lock;
	atomic_t scrubs_running;
	atomic_t scrub_pause_req;
	atomic_t scrubs_paused;
	atomic_t scrub_cancel_req;
	wait_queue_head_t scrub_pause_wait;
	/*
	 * The worker pointers are NULL iff the refcount is 0, ie. scrub is not
	 * running.
	 */
	refcount_t scrub_workers_refcnt;
	struct workqueue_struct *scrub_workers;
	struct workqueue_struct *scrub_wr_completion_workers;
	struct workqueue_struct *scrub_parity_workers;
	struct btrfs_subpage_info *subpage_info;

	struct btrfs_discard_ctl discard_ctl;

#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
	u32 check_integrity_print_mask;
#endif
	/* Is qgroup tracking in a consistent state? */
	u64 qgroup_flags;

	/* Holds configuration and tracking. Protected by qgroup_lock. */
	struct rb_root qgroup_tree;
	spinlock_t qgroup_lock;

	/*
	 * Used to avoid frequently calling ulist_alloc()/ulist_free()
	 * when doing qgroup accounting, it must be protected by qgroup_lock.
	 */
	struct ulist *qgroup_ulist;

	/*
	 * Protect user change for quota operations. If a transaction is needed,
	 * it must be started before locking this lock.
	 */
	struct mutex qgroup_ioctl_lock;

	/* List of dirty qgroups to be written at next commit. */
	struct list_head dirty_qgroups;

	/* Used by qgroup for an efficient tree traversal. */
	u64 qgroup_seq;

	/* Qgroup rescan items. */
	/* Protects the progress item */
	struct mutex qgroup_rescan_lock;
	struct btrfs_key qgroup_rescan_progress;
	struct btrfs_workqueue *qgroup_rescan_workers;
	struct completion qgroup_rescan_completion;
	struct btrfs_work qgroup_rescan_work;
	/* Protected by qgroup_rescan_lock */
	bool qgroup_rescan_running;
	u8 qgroup_drop_subtree_thres;

	/* Filesystem state */
	unsigned long fs_state;

	struct btrfs_delayed_root *delayed_root;

	/* Extent buffer radix tree */
	spinlock_t buffer_lock;
	/* Entries are eb->start / sectorsize */
	struct radix_tree_root buffer_radix;

	/* Next backup root to be overwritten */
	int backup_root_index;

	/* Device replace state */
	struct btrfs_dev_replace dev_replace;

	struct semaphore uuid_tree_rescan_sem;

	/* Used to reclaim the metadata space in the background. */
	struct work_struct async_reclaim_work;
	struct work_struct async_data_reclaim_work;
	struct work_struct preempt_reclaim_work;

	/* Reclaim partially filled block groups in the background */
	struct work_struct reclaim_bgs_work;
	struct list_head reclaim_bgs;
	int bg_reclaim_threshold;

	spinlock_t unused_bgs_lock;
	struct list_head unused_bgs;
	struct mutex unused_bg_unpin_mutex;
	/* Protect block groups that are going to be deleted */
	struct mutex reclaim_bgs_lock;

	/* Cached block sizes */
	u32 nodesize;
	u32 sectorsize;
	/* ilog2 of sectorsize, use to avoid 64bit division */
	u32 sectorsize_bits;
	u32 csum_size;
	u32 csums_per_leaf;
	u32 stripesize;

	/*
	 * Maximum size of an extent. BTRFS_MAX_EXTENT_SIZE on regular
	 * filesystem, on zoned it depends on the device constraints.
	 */
	u64 max_extent_size;

	/* Block groups and devices containing active swapfiles. */
	spinlock_t swapfile_pins_lock;
	struct rb_root swapfile_pins;

	struct crypto_shash *csum_shash;

	/* Type of exclusive operation running, protected by super_lock */
	enum btrfs_exclusive_operation exclusive_operation;

	/*
	 * Zone size > 0 when in ZONED mode, otherwise it's used for a check
	 * if the mode is enabled
	 */
	u64 zone_size;

	/* Max size to emit ZONE_APPEND write command */
	u64 max_zone_append_size;
	struct mutex zoned_meta_io_lock;
	spinlock_t treelog_bg_lock;
	u64 treelog_bg;

	/*
	 * Start of the dedicated data relocation block group, protected by
	 * relocation_bg_lock.
	 */
	spinlock_t relocation_bg_lock;
	u64 data_reloc_bg;
	struct mutex zoned_data_reloc_io_lock;

	u64 nr_global_roots;

	spinlock_t zone_active_bgs_lock;
	struct list_head zone_active_bgs;

	/* Updates are not protected by any lock */
	struct btrfs_commit_stats commit_stats;

	/*
	 * Last generation where we dropped a non-relocation root.
	 * Use btrfs_set_last_root_drop_gen() and btrfs_get_last_root_drop_gen()
	 * to change it and to read it, respectively.
	 */
	u64 last_root_drop_gen;

	/*
	 * Annotations for transaction events (structures are empty when
	 * compiled without lockdep).
	 */
	struct lockdep_map btrfs_trans_num_writers_map;
	struct lockdep_map btrfs_trans_num_extwriters_map;
	struct lockdep_map btrfs_state_change_map[4];
	struct lockdep_map btrfs_trans_pending_ordered_map;
	struct lockdep_map btrfs_ordered_extent_map;

#ifdef CONFIG_BTRFS_FS_REF_VERIFY
	spinlock_t ref_verify_lock;
	struct rb_root block_tree;
#endif

#ifdef CONFIG_BTRFS_DEBUG
	struct kobject *debug_kobj;
	struct list_head allocated_roots;

	spinlock_t eb_leak_lock;
	struct list_head allocated_ebs;
#endif
};

static inline void btrfs_set_last_root_drop_gen(struct btrfs_fs_info *fs_info,
						u64 gen)
{
	WRITE_ONCE(fs_info->last_root_drop_gen, gen);
}

static inline u64 btrfs_get_last_root_drop_gen(const struct btrfs_fs_info *fs_info)
{
	return READ_ONCE(fs_info->last_root_drop_gen);
}

/*
 * Take the number of bytes to be checksummed and figure out how many leaves
 * it would require to store the csums for that many bytes.
 */
static inline u64 btrfs_csum_bytes_to_leaves(
			const struct btrfs_fs_info *fs_info, u64 csum_bytes)
{
	const u64 num_csums = csum_bytes >> fs_info->sectorsize_bits;

	return DIV_ROUND_UP_ULL(num_csums, fs_info->csums_per_leaf);
}

/*
 * Use this if we would be adding new items, as we could split nodes as we cow
 * down the tree.
 */
static inline u64 btrfs_calc_insert_metadata_size(struct btrfs_fs_info *fs_info,
						  unsigned num_items)
{
	return (u64)fs_info->nodesize * BTRFS_MAX_LEVEL * 2 * num_items;
}

/*
 * Doing a truncate or a modification won't result in new nodes or leaves, just
 * what we need for COW.
 */
static inline u64 btrfs_calc_metadata_size(struct btrfs_fs_info *fs_info,
						 unsigned num_items)
{
	return (u64)fs_info->nodesize * BTRFS_MAX_LEVEL * num_items;
}

#define BTRFS_MAX_EXTENT_ITEM_SIZE(r) ((BTRFS_LEAF_DATA_SIZE(r->fs_info) >> 4) - \
					sizeof(struct btrfs_item))

static inline bool btrfs_is_zoned(const struct btrfs_fs_info *fs_info)
{
	return fs_info->zone_size > 0;
}

/*
 * Count how many fs_info->max_extent_size cover the @size
 */
static inline u32 count_max_extents(struct btrfs_fs_info *fs_info, u64 size)
{
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
	if (!fs_info)
		return div_u64(size + BTRFS_MAX_EXTENT_SIZE - 1, BTRFS_MAX_EXTENT_SIZE);
#endif

	return div_u64(size + fs_info->max_extent_size - 1, fs_info->max_extent_size);
}

bool btrfs_exclop_start(struct btrfs_fs_info *fs_info,
			enum btrfs_exclusive_operation type);
bool btrfs_exclop_start_try_lock(struct btrfs_fs_info *fs_info,
				 enum btrfs_exclusive_operation type);
void btrfs_exclop_start_unlock(struct btrfs_fs_info *fs_info);
void btrfs_exclop_finish(struct btrfs_fs_info *fs_info);
void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
			  enum btrfs_exclusive_operation op);

/* Compatibility and incompatibility defines */
void __btrfs_set_fs_incompat(struct btrfs_fs_info *fs_info, u64 flag,
			     const char *name);
void __btrfs_clear_fs_incompat(struct btrfs_fs_info *fs_info, u64 flag,
			       const char *name);
void __btrfs_set_fs_compat_ro(struct btrfs_fs_info *fs_info, u64 flag,
			      const char *name);
void __btrfs_clear_fs_compat_ro(struct btrfs_fs_info *fs_info, u64 flag,
				const char *name);

#define __btrfs_fs_incompat(fs_info, flags)				\
	(!!(btrfs_super_incompat_flags((fs_info)->super_copy) & (flags)))

#define __btrfs_fs_compat_ro(fs_info, flags)				\
	(!!(btrfs_super_compat_ro_flags((fs_info)->super_copy) & (flags)))

#define btrfs_set_fs_incompat(__fs_info, opt)				\
	__btrfs_set_fs_incompat((__fs_info), BTRFS_FEATURE_INCOMPAT_##opt, #opt)

#define btrfs_clear_fs_incompat(__fs_info, opt)				\
	__btrfs_clear_fs_incompat((__fs_info), BTRFS_FEATURE_INCOMPAT_##opt, #opt)

#define btrfs_fs_incompat(fs_info, opt)					\
	__btrfs_fs_incompat((fs_info), BTRFS_FEATURE_INCOMPAT_##opt)

#define btrfs_set_fs_compat_ro(__fs_info, opt)				\
	__btrfs_set_fs_compat_ro((__fs_info), BTRFS_FEATURE_COMPAT_RO_##opt, #opt)

#define btrfs_clear_fs_compat_ro(__fs_info, opt)			\
	__btrfs_clear_fs_compat_ro((__fs_info), BTRFS_FEATURE_COMPAT_RO_##opt, #opt)

#define btrfs_fs_compat_ro(fs_info, opt)				\
	__btrfs_fs_compat_ro((fs_info), BTRFS_FEATURE_COMPAT_RO_##opt)

#define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)
#define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)
#define btrfs_raw_test_opt(o, opt)	((o) & BTRFS_MOUNT_##opt)
#define btrfs_test_opt(fs_info, opt)	((fs_info)->mount_opt & \
					 BTRFS_MOUNT_##opt)

#define btrfs_set_and_info(fs_info, opt, fmt, args...)			\
do {									\
	if (!btrfs_test_opt(fs_info, opt))				\
		btrfs_info(fs_info, fmt, ##args);			\
	btrfs_set_opt(fs_info->mount_opt, opt);				\
} while (0)

#define btrfs_clear_and_info(fs_info, opt, fmt, args...)		\
do {									\
	if (btrfs_test_opt(fs_info, opt))				\
		btrfs_info(fs_info, fmt, ##args);			\
	btrfs_clear_opt(fs_info->mount_opt, opt);			\
} while (0)

static inline int btrfs_fs_closing(struct btrfs_fs_info *fs_info)
{
	/* Do it this way so we only ever do one test_bit in the normal case. */
	if (test_bit(BTRFS_FS_CLOSING_START, &fs_info->flags)) {
		if (test_bit(BTRFS_FS_CLOSING_DONE, &fs_info->flags))
			return 2;
		return 1;
	}
	return 0;
}

/*
 * If we remount the fs to be R/O or umount the fs, the cleaner needn't do
 * anything except sleeping. This function is used to check the status of
 * the fs.
 * We check for BTRFS_FS_STATE_RO to avoid races with a concurrent remount,
 * since setting and checking for SB_RDONLY in the superblock's flags is not
 * atomic.
 */
static inline int btrfs_need_cleaner_sleep(struct btrfs_fs_info *fs_info)
{
	return test_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state) ||
		btrfs_fs_closing(fs_info);
}

static inline void btrfs_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
{
	clear_and_wake_up_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags);
}

#define BTRFS_FS_ERROR(fs_info)	(unlikely(test_bit(BTRFS_FS_STATE_ERROR, \
						   &(fs_info)->fs_state)))
#define BTRFS_FS_LOG_CLEANUP_ERROR(fs_info)				\
	(unlikely(test_bit(BTRFS_FS_STATE_LOG_CLEANUP_ERROR,		\
			   &(fs_info)->fs_state)))

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS

#define EXPORT_FOR_TESTS

static inline int btrfs_is_testing(struct btrfs_fs_info *fs_info)
{
	return test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state);
}

void btrfs_test_destroy_inode(struct inode *inode);

#else

#define EXPORT_FOR_TESTS static

static inline int btrfs_is_testing(struct btrfs_fs_info *fs_info)
{
	return 0;
}
#endif

#endif