xref: /linux/fs/btrfs/fs.h (revision b17ef04bf3a4346d66404454d6a646343ddc9749)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 
3 #ifndef BTRFS_FS_H
4 #define BTRFS_FS_H
5 
6 #include <linux/blkdev.h>
7 #include <linux/fs.h>
8 #include <linux/btrfs_tree.h>
9 #include <linux/sizes.h>
10 #include "extent-io-tree.h"
11 #include "extent_map.h"
12 #include "async-thread.h"
13 #include "block-rsv.h"
14 
15 #define BTRFS_MAX_EXTENT_SIZE SZ_128M
16 
17 #define BTRFS_OLDEST_GENERATION	0ULL
18 
19 #define BTRFS_EMPTY_DIR_SIZE 0
20 
21 #define BTRFS_DIRTY_METADATA_THRESH		SZ_32M
22 
23 #define BTRFS_SUPER_INFO_OFFSET			SZ_64K
24 #define BTRFS_SUPER_INFO_SIZE			4096
25 static_assert(sizeof(struct btrfs_super_block) == BTRFS_SUPER_INFO_SIZE);
26 
27 /*
28  * Number of metadata items necessary for an unlink operation:
29  *
30  * 1 for the possible orphan item
31  * 1 for the dir item
32  * 1 for the dir index
33  * 1 for the inode ref
34  * 1 for the inode
35  * 1 for the parent inode
36  */
37 #define BTRFS_UNLINK_METADATA_UNITS		6
38 
39 /*
40  * The reserved space at the beginning of each device.  It covers the primary
41  * super block and leaves space for potential use by other tools like
42  * bootloaders or to lower potential damage of accidental overwrite.
43  */
44 #define BTRFS_DEVICE_RANGE_RESERVED			(SZ_1M)
45 /*
46  * Runtime (in-memory) states of filesystem
47  */
48 enum {
49 	/*
50 	 * Filesystem is being remounted, allow to skip some operations, like
51 	 * defrag
52 	 */
53 	BTRFS_FS_STATE_REMOUNTING,
54 	/* Filesystem in RO mode */
55 	BTRFS_FS_STATE_RO,
56 	/* Track if a transaction abort has been reported on this filesystem */
57 	BTRFS_FS_STATE_TRANS_ABORTED,
58 	/*
59 	 * Bio operations should be blocked on this filesystem because a source
60 	 * or target device is being destroyed as part of a device replace
61 	 */
62 	BTRFS_FS_STATE_DEV_REPLACING,
63 	/* The btrfs_fs_info created for self-tests */
64 	BTRFS_FS_STATE_DUMMY_FS_INFO,
65 
66 	BTRFS_FS_STATE_NO_CSUMS,
67 
68 	/* Indicates there was an error cleaning up a log tree. */
69 	BTRFS_FS_STATE_LOG_CLEANUP_ERROR,
70 
71 	BTRFS_FS_STATE_COUNT
72 };
73 
74 enum {
75 	BTRFS_FS_CLOSING_START,
76 	BTRFS_FS_CLOSING_DONE,
77 	BTRFS_FS_LOG_RECOVERING,
78 	BTRFS_FS_OPEN,
79 	BTRFS_FS_QUOTA_ENABLED,
80 	BTRFS_FS_UPDATE_UUID_TREE_GEN,
81 	BTRFS_FS_CREATING_FREE_SPACE_TREE,
82 	BTRFS_FS_BTREE_ERR,
83 	BTRFS_FS_LOG1_ERR,
84 	BTRFS_FS_LOG2_ERR,
85 	BTRFS_FS_QUOTA_OVERRIDE,
86 	/* Used to record internally whether fs has been frozen */
87 	BTRFS_FS_FROZEN,
88 	/*
89 	 * Indicate that balance has been set up from the ioctl and is in the
90 	 * main phase. The fs_info::balance_ctl is initialized.
91 	 */
92 	BTRFS_FS_BALANCE_RUNNING,
93 
94 	/*
95 	 * Indicate that relocation of a chunk has started, it's set per chunk
96 	 * and is toggled between chunks.
97 	 */
98 	BTRFS_FS_RELOC_RUNNING,
99 
100 	/* Indicate that the cleaner thread is awake and doing something. */
101 	BTRFS_FS_CLEANER_RUNNING,
102 
103 	/*
104 	 * The checksumming has an optimized version and is considered fast,
105 	 * so we don't need to offload checksums to workqueues.
106 	 */
107 	BTRFS_FS_CSUM_IMPL_FAST,
108 
109 	/* Indicate that the discard workqueue can service discards. */
110 	BTRFS_FS_DISCARD_RUNNING,
111 
112 	/* Indicate that we need to cleanup space cache v1 */
113 	BTRFS_FS_CLEANUP_SPACE_CACHE_V1,
114 
115 	/* Indicate that we can't trust the free space tree for caching yet */
116 	BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED,
117 
118 	/* Indicate whether there are any tree modification log users */
119 	BTRFS_FS_TREE_MOD_LOG_USERS,
120 
121 	/* Indicate that we want the transaction kthread to commit right now. */
122 	BTRFS_FS_COMMIT_TRANS,
123 
124 	/* Indicate we have half completed snapshot deletions pending. */
125 	BTRFS_FS_UNFINISHED_DROPS,
126 
127 	/* Indicate we have to finish a zone to do next allocation. */
128 	BTRFS_FS_NEED_ZONE_FINISH,
129 
130 	/* Indicate that we want to commit the transaction. */
131 	BTRFS_FS_NEED_TRANS_COMMIT,
132 
133 	/* This is set when active zone tracking is needed. */
134 	BTRFS_FS_ACTIVE_ZONE_TRACKING,
135 
136 	/*
137 	 * Indicate if we have some features changed, this is mostly for
138 	 * cleaner thread to update the sysfs interface.
139 	 */
140 	BTRFS_FS_FEATURE_CHANGED,
141 
142 	/*
143 	 * Indicate that we have found a tree block which is only aligned to
144 	 * sectorsize, but not to nodesize.  This should be rare nowadays.
145 	 */
146 	BTRFS_FS_UNALIGNED_TREE_BLOCK,
147 
148 #if BITS_PER_LONG == 32
149 	/* Indicate if we have error/warn message printed on 32bit systems */
150 	BTRFS_FS_32BIT_ERROR,
151 	BTRFS_FS_32BIT_WARN,
152 #endif
153 };
154 
155 /*
156  * Flags for mount options.
157  *
158  * Note: don't forget to add new options to btrfs_show_options()
159  */
160 enum {
161 	BTRFS_MOUNT_NODATASUM			= (1UL << 0),
162 	BTRFS_MOUNT_NODATACOW			= (1UL << 1),
163 	BTRFS_MOUNT_NOBARRIER			= (1UL << 2),
164 	BTRFS_MOUNT_SSD				= (1UL << 3),
165 	BTRFS_MOUNT_DEGRADED			= (1UL << 4),
166 	BTRFS_MOUNT_COMPRESS			= (1UL << 5),
167 	BTRFS_MOUNT_NOTREELOG   		= (1UL << 6),
168 	BTRFS_MOUNT_FLUSHONCOMMIT		= (1UL << 7),
169 	BTRFS_MOUNT_SSD_SPREAD			= (1UL << 8),
170 	BTRFS_MOUNT_NOSSD			= (1UL << 9),
171 	BTRFS_MOUNT_DISCARD_SYNC		= (1UL << 10),
172 	BTRFS_MOUNT_FORCE_COMPRESS      	= (1UL << 11),
173 	BTRFS_MOUNT_SPACE_CACHE			= (1UL << 12),
174 	BTRFS_MOUNT_CLEAR_CACHE			= (1UL << 13),
175 	BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED	= (1UL << 14),
176 	BTRFS_MOUNT_ENOSPC_DEBUG		= (1UL << 15),
177 	BTRFS_MOUNT_AUTO_DEFRAG			= (1UL << 16),
178 	BTRFS_MOUNT_USEBACKUPROOT		= (1UL << 17),
179 	BTRFS_MOUNT_SKIP_BALANCE		= (1UL << 18),
180 	BTRFS_MOUNT_PANIC_ON_FATAL_ERROR	= (1UL << 19),
181 	BTRFS_MOUNT_RESCAN_UUID_TREE		= (1UL << 20),
182 	BTRFS_MOUNT_FRAGMENT_DATA		= (1UL << 21),
183 	BTRFS_MOUNT_FRAGMENT_METADATA		= (1UL << 22),
184 	BTRFS_MOUNT_FREE_SPACE_TREE		= (1UL << 23),
185 	BTRFS_MOUNT_NOLOGREPLAY			= (1UL << 24),
186 	BTRFS_MOUNT_REF_VERIFY			= (1UL << 25),
187 	BTRFS_MOUNT_DISCARD_ASYNC		= (1UL << 26),
188 	BTRFS_MOUNT_IGNOREBADROOTS		= (1UL << 27),
189 	BTRFS_MOUNT_IGNOREDATACSUMS		= (1UL << 28),
190 	BTRFS_MOUNT_NODISCARD			= (1UL << 29),
191 };
192 
193 /*
194  * Compat flags that we support.  If any incompat flags are set other than the
195  * ones specified below then we will fail to mount
196  */
197 #define BTRFS_FEATURE_COMPAT_SUPP		0ULL
198 #define BTRFS_FEATURE_COMPAT_SAFE_SET		0ULL
199 #define BTRFS_FEATURE_COMPAT_SAFE_CLEAR		0ULL
200 
201 #define BTRFS_FEATURE_COMPAT_RO_SUPP			\
202 	(BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE |	\
203 	 BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE_VALID | \
204 	 BTRFS_FEATURE_COMPAT_RO_VERITY |		\
205 	 BTRFS_FEATURE_COMPAT_RO_BLOCK_GROUP_TREE)
206 
207 #define BTRFS_FEATURE_COMPAT_RO_SAFE_SET	0ULL
208 #define BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR	0ULL
209 
210 #define BTRFS_FEATURE_INCOMPAT_SUPP_STABLE		\
211 	(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |		\
212 	 BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |	\
213 	 BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |		\
214 	 BTRFS_FEATURE_INCOMPAT_BIG_METADATA |		\
215 	 BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO |		\
216 	 BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD |		\
217 	 BTRFS_FEATURE_INCOMPAT_RAID56 |		\
218 	 BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |		\
219 	 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |	\
220 	 BTRFS_FEATURE_INCOMPAT_NO_HOLES	|	\
221 	 BTRFS_FEATURE_INCOMPAT_METADATA_UUID	|	\
222 	 BTRFS_FEATURE_INCOMPAT_RAID1C34	|	\
223 	 BTRFS_FEATURE_INCOMPAT_ZONED		|	\
224 	 BTRFS_FEATURE_INCOMPAT_SIMPLE_QUOTA)
225 
226 #ifdef CONFIG_BTRFS_DEBUG
227 	/*
228 	 * Features under developmen like Extent tree v2 support is enabled
229 	 * only under CONFIG_BTRFS_DEBUG.
230 	 */
231 #define BTRFS_FEATURE_INCOMPAT_SUPP		\
232 	(BTRFS_FEATURE_INCOMPAT_SUPP_STABLE |	\
233 	 BTRFS_FEATURE_INCOMPAT_RAID_STRIPE_TREE | \
234 	 BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2)
235 
236 #else
237 
238 #define BTRFS_FEATURE_INCOMPAT_SUPP		\
239 	(BTRFS_FEATURE_INCOMPAT_SUPP_STABLE)
240 
241 #endif
242 
243 #define BTRFS_FEATURE_INCOMPAT_SAFE_SET			\
244 	(BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
245 #define BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR		0ULL
246 
247 #define BTRFS_DEFAULT_COMMIT_INTERVAL	(30)
248 #define BTRFS_DEFAULT_MAX_INLINE	(2048)
249 
250 struct btrfs_dev_replace {
251 	/* See #define above */
252 	u64 replace_state;
253 	/* Seconds since 1-Jan-1970 */
254 	time64_t time_started;
255 	/* Seconds since 1-Jan-1970 */
256 	time64_t time_stopped;
257 	atomic64_t num_write_errors;
258 	atomic64_t num_uncorrectable_read_errors;
259 
260 	u64 cursor_left;
261 	u64 committed_cursor_left;
262 	u64 cursor_left_last_write_of_item;
263 	u64 cursor_right;
264 
265 	/* See #define above */
266 	u64 cont_reading_from_srcdev_mode;
267 
268 	int is_valid;
269 	int item_needs_writeback;
270 	struct btrfs_device *srcdev;
271 	struct btrfs_device *tgtdev;
272 
273 	struct mutex lock_finishing_cancel_unmount;
274 	struct rw_semaphore rwsem;
275 
276 	struct btrfs_scrub_progress scrub_progress;
277 
278 	struct percpu_counter bio_counter;
279 	wait_queue_head_t replace_wait;
280 };
281 
282 /*
283  * Free clusters are used to claim free space in relatively large chunks,
284  * allowing us to do less seeky writes. They are used for all metadata
285  * allocations. In ssd_spread mode they are also used for data allocations.
286  */
287 struct btrfs_free_cluster {
288 	spinlock_t lock;
289 	spinlock_t refill_lock;
290 	struct rb_root root;
291 
292 	/* Largest extent in this cluster */
293 	u64 max_size;
294 
295 	/* First extent starting offset */
296 	u64 window_start;
297 
298 	/* We did a full search and couldn't create a cluster */
299 	bool fragmented;
300 
301 	struct btrfs_block_group *block_group;
302 	/*
303 	 * When a cluster is allocated from a block group, we put the cluster
304 	 * onto a list in the block group so that it can be freed before the
305 	 * block group is freed.
306 	 */
307 	struct list_head block_group_list;
308 };
309 
310 /* Discard control. */
311 /*
312  * Async discard uses multiple lists to differentiate the discard filter
313  * parameters.  Index 0 is for completely free block groups where we need to
314  * ensure the entire block group is trimmed without being lossy.  Indices
315  * afterwards represent monotonically decreasing discard filter sizes to
316  * prioritize what should be discarded next.
317  */
318 #define BTRFS_NR_DISCARD_LISTS		3
319 #define BTRFS_DISCARD_INDEX_UNUSED	0
320 #define BTRFS_DISCARD_INDEX_START	1
321 
322 struct btrfs_discard_ctl {
323 	struct workqueue_struct *discard_workers;
324 	struct delayed_work work;
325 	spinlock_t lock;
326 	struct btrfs_block_group *block_group;
327 	struct list_head discard_list[BTRFS_NR_DISCARD_LISTS];
328 	u64 prev_discard;
329 	u64 prev_discard_time;
330 	atomic_t discardable_extents;
331 	atomic64_t discardable_bytes;
332 	u64 max_discard_size;
333 	u64 delay_ms;
334 	u32 iops_limit;
335 	u32 kbps_limit;
336 	u64 discard_extent_bytes;
337 	u64 discard_bitmap_bytes;
338 	atomic64_t discard_bytes_saved;
339 };
340 
341 /*
342  * Exclusive operations (device replace, resize, device add/remove, balance)
343  */
344 enum btrfs_exclusive_operation {
345 	BTRFS_EXCLOP_NONE,
346 	BTRFS_EXCLOP_BALANCE_PAUSED,
347 	BTRFS_EXCLOP_BALANCE,
348 	BTRFS_EXCLOP_DEV_ADD,
349 	BTRFS_EXCLOP_DEV_REMOVE,
350 	BTRFS_EXCLOP_DEV_REPLACE,
351 	BTRFS_EXCLOP_RESIZE,
352 	BTRFS_EXCLOP_SWAP_ACTIVATE,
353 };
354 
355 /* Store data about transaction commits, exported via sysfs. */
356 struct btrfs_commit_stats {
357 	/* Total number of commits */
358 	u64 commit_count;
359 	/* The maximum commit duration so far in ns */
360 	u64 max_commit_dur;
361 	/* The last commit duration in ns */
362 	u64 last_commit_dur;
363 	/* The total commit duration in ns */
364 	u64 total_commit_dur;
365 };
366 
367 struct btrfs_fs_info {
368 	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
369 	unsigned long flags;
370 	struct btrfs_root *tree_root;
371 	struct btrfs_root *chunk_root;
372 	struct btrfs_root *dev_root;
373 	struct btrfs_root *fs_root;
374 	struct btrfs_root *quota_root;
375 	struct btrfs_root *uuid_root;
376 	struct btrfs_root *data_reloc_root;
377 	struct btrfs_root *block_group_root;
378 	struct btrfs_root *stripe_root;
379 
380 	/* The log root tree is a directory of all the other log roots */
381 	struct btrfs_root *log_root_tree;
382 
383 	/* The tree that holds the global roots (csum, extent, etc) */
384 	rwlock_t global_root_lock;
385 	struct rb_root global_root_tree;
386 
387 	spinlock_t fs_roots_radix_lock;
388 	struct radix_tree_root fs_roots_radix;
389 
390 	/* Block group cache stuff */
391 	rwlock_t block_group_cache_lock;
392 	struct rb_root_cached block_group_cache_tree;
393 
394 	/* Keep track of unallocated space */
395 	atomic64_t free_chunk_space;
396 
397 	/* Track ranges which are used by log trees blocks/logged data extents */
398 	struct extent_io_tree excluded_extents;
399 
400 	/* logical->physical extent mapping */
401 	struct extent_map_tree mapping_tree;
402 
403 	/*
404 	 * Block reservation for extent, checksum, root tree and delayed dir
405 	 * index item.
406 	 */
407 	struct btrfs_block_rsv global_block_rsv;
408 	/* Block reservation for metadata operations */
409 	struct btrfs_block_rsv trans_block_rsv;
410 	/* Block reservation for chunk tree */
411 	struct btrfs_block_rsv chunk_block_rsv;
412 	/* Block reservation for delayed operations */
413 	struct btrfs_block_rsv delayed_block_rsv;
414 	/* Block reservation for delayed refs */
415 	struct btrfs_block_rsv delayed_refs_rsv;
416 
417 	struct btrfs_block_rsv empty_block_rsv;
418 
419 	/*
420 	 * Updated while holding the lock 'trans_lock'. Due to the life cycle of
421 	 * a transaction, it can be directly read while holding a transaction
422 	 * handle, everywhere else must be read with btrfs_get_fs_generation().
423 	 * Should always be updated using btrfs_set_fs_generation().
424 	 */
425 	u64 generation;
426 	/*
427 	 * Always use btrfs_get_last_trans_committed() and
428 	 * btrfs_set_last_trans_committed() to read and update this field.
429 	 */
430 	u64 last_trans_committed;
431 	/*
432 	 * Generation of the last transaction used for block group relocation
433 	 * since the filesystem was last mounted (or 0 if none happened yet).
434 	 * Must be written and read while holding btrfs_fs_info::commit_root_sem.
435 	 */
436 	u64 last_reloc_trans;
437 
438 	/*
439 	 * This is updated to the current trans every time a full commit is
440 	 * required instead of the faster short fsync log commits
441 	 */
442 	u64 last_trans_log_full_commit;
443 	unsigned long mount_opt;
444 
445 	unsigned long compress_type:4;
446 	unsigned int compress_level;
447 	u32 commit_interval;
448 	/*
449 	 * It is a suggestive number, the read side is safe even it gets a
450 	 * wrong number because we will write out the data into a regular
451 	 * extent. The write side(mount/remount) is under ->s_umount lock,
452 	 * so it is also safe.
453 	 */
454 	u64 max_inline;
455 
456 	struct btrfs_transaction *running_transaction;
457 	wait_queue_head_t transaction_throttle;
458 	wait_queue_head_t transaction_wait;
459 	wait_queue_head_t transaction_blocked_wait;
460 	wait_queue_head_t async_submit_wait;
461 
462 	/*
463 	 * Used to protect the incompat_flags, compat_flags, compat_ro_flags
464 	 * when they are updated.
465 	 *
466 	 * Because we do not clear the flags for ever, so we needn't use
467 	 * the lock on the read side.
468 	 *
469 	 * We also needn't use the lock when we mount the fs, because
470 	 * there is no other task which will update the flag.
471 	 */
472 	spinlock_t super_lock;
473 	struct btrfs_super_block *super_copy;
474 	struct btrfs_super_block *super_for_commit;
475 	struct super_block *sb;
476 	struct inode *btree_inode;
477 	struct mutex tree_log_mutex;
478 	struct mutex transaction_kthread_mutex;
479 	struct mutex cleaner_mutex;
480 	struct mutex chunk_mutex;
481 
482 	/*
483 	 * This is taken to make sure we don't set block groups ro after the
484 	 * free space cache has been allocated on them.
485 	 */
486 	struct mutex ro_block_group_mutex;
487 
488 	/*
489 	 * This is used during read/modify/write to make sure no two ios are
490 	 * trying to mod the same stripe at the same time.
491 	 */
492 	struct btrfs_stripe_hash_table *stripe_hash_table;
493 
494 	/*
495 	 * This protects the ordered operations list only while we are
496 	 * processing all of the entries on it.  This way we make sure the
497 	 * commit code doesn't find the list temporarily empty because another
498 	 * function happens to be doing non-waiting preflush before jumping
499 	 * into the main commit.
500 	 */
501 	struct mutex ordered_operations_mutex;
502 
503 	struct rw_semaphore commit_root_sem;
504 
505 	struct rw_semaphore cleanup_work_sem;
506 
507 	struct rw_semaphore subvol_sem;
508 
509 	spinlock_t trans_lock;
510 	/*
511 	 * The reloc mutex goes with the trans lock, it is taken during commit
512 	 * to protect us from the relocation code.
513 	 */
514 	struct mutex reloc_mutex;
515 
516 	struct list_head trans_list;
517 	struct list_head dead_roots;
518 	struct list_head caching_block_groups;
519 
520 	spinlock_t delayed_iput_lock;
521 	struct list_head delayed_iputs;
522 	atomic_t nr_delayed_iputs;
523 	wait_queue_head_t delayed_iputs_wait;
524 
525 	atomic64_t tree_mod_seq;
526 
527 	/* This protects tree_mod_log and tree_mod_seq_list */
528 	rwlock_t tree_mod_log_lock;
529 	struct rb_root tree_mod_log;
530 	struct list_head tree_mod_seq_list;
531 
532 	atomic_t async_delalloc_pages;
533 
534 	/* This is used to protect the following list -- ordered_roots. */
535 	spinlock_t ordered_root_lock;
536 
537 	/*
538 	 * All fs/file tree roots in which there are data=ordered extents
539 	 * pending writeback are added into this list.
540 	 *
541 	 * These can span multiple transactions and basically include every
542 	 * dirty data page that isn't from nodatacow.
543 	 */
544 	struct list_head ordered_roots;
545 
546 	struct mutex delalloc_root_mutex;
547 	spinlock_t delalloc_root_lock;
548 	/* All fs/file tree roots that have delalloc inodes. */
549 	struct list_head delalloc_roots;
550 
551 	/*
552 	 * There is a pool of worker threads for checksumming during writes and
553 	 * a pool for checksumming after reads.  This is because readers can
554 	 * run with FS locks held, and the writers may be waiting for those
555 	 * locks.  We don't want ordering in the pending list to cause
556 	 * deadlocks, and so the two are serviced separately.
557 	 *
558 	 * A third pool does submit_bio to avoid deadlocking with the other two.
559 	 */
560 	struct btrfs_workqueue *workers;
561 	struct btrfs_workqueue *delalloc_workers;
562 	struct btrfs_workqueue *flush_workers;
563 	struct workqueue_struct *endio_workers;
564 	struct workqueue_struct *endio_meta_workers;
565 	struct workqueue_struct *rmw_workers;
566 	struct workqueue_struct *compressed_write_workers;
567 	struct btrfs_workqueue *endio_write_workers;
568 	struct btrfs_workqueue *endio_freespace_worker;
569 	struct btrfs_workqueue *caching_workers;
570 
571 	/*
572 	 * Fixup workers take dirty pages that didn't properly go through the
573 	 * cow mechanism and make them safe to write.  It happens for the
574 	 * sys_munmap function call path.
575 	 */
576 	struct btrfs_workqueue *fixup_workers;
577 	struct btrfs_workqueue *delayed_workers;
578 
579 	struct task_struct *transaction_kthread;
580 	struct task_struct *cleaner_kthread;
581 	u32 thread_pool_size;
582 
583 	struct kobject *space_info_kobj;
584 	struct kobject *qgroups_kobj;
585 	struct kobject *discard_kobj;
586 
587 	/* Used to keep from writing metadata until there is a nice batch */
588 	struct percpu_counter dirty_metadata_bytes;
589 	struct percpu_counter delalloc_bytes;
590 	struct percpu_counter ordered_bytes;
591 	s32 dirty_metadata_batch;
592 	s32 delalloc_batch;
593 
594 	/* Protected by 'trans_lock'. */
595 	struct list_head dirty_cowonly_roots;
596 
597 	struct btrfs_fs_devices *fs_devices;
598 
599 	/*
600 	 * The space_info list is effectively read only after initial setup.
601 	 * It is populated at mount time and cleaned up after all block groups
602 	 * are removed.  RCU is used to protect it.
603 	 */
604 	struct list_head space_info;
605 
606 	struct btrfs_space_info *data_sinfo;
607 
608 	struct reloc_control *reloc_ctl;
609 
610 	/* data_alloc_cluster is only used in ssd_spread mode */
611 	struct btrfs_free_cluster data_alloc_cluster;
612 
613 	/* All metadata allocations go through this cluster. */
614 	struct btrfs_free_cluster meta_alloc_cluster;
615 
616 	/* Auto defrag inodes go here. */
617 	spinlock_t defrag_inodes_lock;
618 	struct rb_root defrag_inodes;
619 	atomic_t defrag_running;
620 
621 	/* Used to protect avail_{data, metadata, system}_alloc_bits */
622 	seqlock_t profiles_lock;
623 	/*
624 	 * These three are in extended format (availability of single chunks is
625 	 * denoted by BTRFS_AVAIL_ALLOC_BIT_SINGLE bit, other types are denoted
626 	 * by corresponding BTRFS_BLOCK_GROUP_* bits)
627 	 */
628 	u64 avail_data_alloc_bits;
629 	u64 avail_metadata_alloc_bits;
630 	u64 avail_system_alloc_bits;
631 
632 	/* Balance state */
633 	spinlock_t balance_lock;
634 	struct mutex balance_mutex;
635 	atomic_t balance_pause_req;
636 	atomic_t balance_cancel_req;
637 	struct btrfs_balance_control *balance_ctl;
638 	wait_queue_head_t balance_wait_q;
639 
640 	/* Cancellation requests for chunk relocation */
641 	atomic_t reloc_cancel_req;
642 
643 	u32 data_chunk_allocations;
644 	u32 metadata_ratio;
645 
646 	void *bdev_holder;
647 
648 	/* Private scrub information */
649 	struct mutex scrub_lock;
650 	atomic_t scrubs_running;
651 	atomic_t scrub_pause_req;
652 	atomic_t scrubs_paused;
653 	atomic_t scrub_cancel_req;
654 	wait_queue_head_t scrub_pause_wait;
655 	/*
656 	 * The worker pointers are NULL iff the refcount is 0, ie. scrub is not
657 	 * running.
658 	 */
659 	refcount_t scrub_workers_refcnt;
660 	struct workqueue_struct *scrub_workers;
661 	struct btrfs_subpage_info *subpage_info;
662 
663 	struct btrfs_discard_ctl discard_ctl;
664 
665 	/* Is qgroup tracking in a consistent state? */
666 	u64 qgroup_flags;
667 
668 	/* Holds configuration and tracking. Protected by qgroup_lock. */
669 	struct rb_root qgroup_tree;
670 	spinlock_t qgroup_lock;
671 
672 	/*
673 	 * Used to avoid frequently calling ulist_alloc()/ulist_free()
674 	 * when doing qgroup accounting, it must be protected by qgroup_lock.
675 	 */
676 	struct ulist *qgroup_ulist;
677 
678 	/*
679 	 * Protect user change for quota operations. If a transaction is needed,
680 	 * it must be started before locking this lock.
681 	 */
682 	struct mutex qgroup_ioctl_lock;
683 
684 	/* List of dirty qgroups to be written at next commit. */
685 	struct list_head dirty_qgroups;
686 
687 	/* Used by qgroup for an efficient tree traversal. */
688 	u64 qgroup_seq;
689 
690 	/* Qgroup rescan items. */
691 	/* Protects the progress item */
692 	struct mutex qgroup_rescan_lock;
693 	struct btrfs_key qgroup_rescan_progress;
694 	struct btrfs_workqueue *qgroup_rescan_workers;
695 	struct completion qgroup_rescan_completion;
696 	struct btrfs_work qgroup_rescan_work;
697 	/* Protected by qgroup_rescan_lock */
698 	bool qgroup_rescan_running;
699 	u8 qgroup_drop_subtree_thres;
700 	u64 qgroup_enable_gen;
701 
702 	/*
703 	 * If this is not 0, then it indicates a serious filesystem error has
704 	 * happened and it contains that error (negative errno value).
705 	 */
706 	int fs_error;
707 
708 	/* Filesystem state */
709 	unsigned long fs_state;
710 
711 	struct btrfs_delayed_root *delayed_root;
712 
713 	/* Extent buffer radix tree */
714 	spinlock_t buffer_lock;
715 	/* Entries are eb->start / sectorsize */
716 	struct radix_tree_root buffer_radix;
717 
718 	/* Next backup root to be overwritten */
719 	int backup_root_index;
720 
721 	/* Device replace state */
722 	struct btrfs_dev_replace dev_replace;
723 
724 	struct semaphore uuid_tree_rescan_sem;
725 
726 	/* Used to reclaim the metadata space in the background. */
727 	struct work_struct async_reclaim_work;
728 	struct work_struct async_data_reclaim_work;
729 	struct work_struct preempt_reclaim_work;
730 
731 	/* Reclaim partially filled block groups in the background */
732 	struct work_struct reclaim_bgs_work;
733 	struct list_head reclaim_bgs;
734 	int bg_reclaim_threshold;
735 
736 	spinlock_t unused_bgs_lock;
737 	struct list_head unused_bgs;
738 	struct mutex unused_bg_unpin_mutex;
739 	/* Protect block groups that are going to be deleted */
740 	struct mutex reclaim_bgs_lock;
741 
742 	/* Cached block sizes */
743 	u32 nodesize;
744 	u32 sectorsize;
745 	/* ilog2 of sectorsize, use to avoid 64bit division */
746 	u32 sectorsize_bits;
747 	u32 csum_size;
748 	u32 csums_per_leaf;
749 	u32 stripesize;
750 
751 	/*
752 	 * Maximum size of an extent. BTRFS_MAX_EXTENT_SIZE on regular
753 	 * filesystem, on zoned it depends on the device constraints.
754 	 */
755 	u64 max_extent_size;
756 
757 	/* Block groups and devices containing active swapfiles. */
758 	spinlock_t swapfile_pins_lock;
759 	struct rb_root swapfile_pins;
760 
761 	struct crypto_shash *csum_shash;
762 
763 	/* Type of exclusive operation running, protected by super_lock */
764 	enum btrfs_exclusive_operation exclusive_operation;
765 
766 	/*
767 	 * Zone size > 0 when in ZONED mode, otherwise it's used for a check
768 	 * if the mode is enabled
769 	 */
770 	u64 zone_size;
771 
772 	/* Constraints for ZONE_APPEND commands: */
773 	struct queue_limits limits;
774 	u64 max_zone_append_size;
775 
776 	struct mutex zoned_meta_io_lock;
777 	spinlock_t treelog_bg_lock;
778 	u64 treelog_bg;
779 
780 	/*
781 	 * Start of the dedicated data relocation block group, protected by
782 	 * relocation_bg_lock.
783 	 */
784 	spinlock_t relocation_bg_lock;
785 	u64 data_reloc_bg;
786 	struct mutex zoned_data_reloc_io_lock;
787 
788 	struct btrfs_block_group *active_meta_bg;
789 	struct btrfs_block_group *active_system_bg;
790 
791 	u64 nr_global_roots;
792 
793 	spinlock_t zone_active_bgs_lock;
794 	struct list_head zone_active_bgs;
795 
796 	/* Updates are not protected by any lock */
797 	struct btrfs_commit_stats commit_stats;
798 
799 	/*
800 	 * Last generation where we dropped a non-relocation root.
801 	 * Use btrfs_set_last_root_drop_gen() and btrfs_get_last_root_drop_gen()
802 	 * to change it and to read it, respectively.
803 	 */
804 	u64 last_root_drop_gen;
805 
806 	/*
807 	 * Annotations for transaction events (structures are empty when
808 	 * compiled without lockdep).
809 	 */
810 	struct lockdep_map btrfs_trans_num_writers_map;
811 	struct lockdep_map btrfs_trans_num_extwriters_map;
812 	struct lockdep_map btrfs_state_change_map[4];
813 	struct lockdep_map btrfs_trans_pending_ordered_map;
814 	struct lockdep_map btrfs_ordered_extent_map;
815 
816 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
817 	spinlock_t ref_verify_lock;
818 	struct rb_root block_tree;
819 #endif
820 
821 #ifdef CONFIG_BTRFS_DEBUG
822 	struct kobject *debug_kobj;
823 	struct list_head allocated_roots;
824 
825 	spinlock_t eb_leak_lock;
826 	struct list_head allocated_ebs;
827 #endif
828 };
829 
830 static inline u64 btrfs_get_fs_generation(const struct btrfs_fs_info *fs_info)
831 {
832 	return READ_ONCE(fs_info->generation);
833 }
834 
835 static inline void btrfs_set_fs_generation(struct btrfs_fs_info *fs_info, u64 gen)
836 {
837 	WRITE_ONCE(fs_info->generation, gen);
838 }
839 
840 static inline u64 btrfs_get_last_trans_committed(const struct btrfs_fs_info *fs_info)
841 {
842 	return READ_ONCE(fs_info->last_trans_committed);
843 }
844 
845 static inline void btrfs_set_last_trans_committed(struct btrfs_fs_info *fs_info, u64 gen)
846 {
847 	WRITE_ONCE(fs_info->last_trans_committed, gen);
848 }
849 
850 static inline void btrfs_set_last_root_drop_gen(struct btrfs_fs_info *fs_info,
851 						u64 gen)
852 {
853 	WRITE_ONCE(fs_info->last_root_drop_gen, gen);
854 }
855 
856 static inline u64 btrfs_get_last_root_drop_gen(const struct btrfs_fs_info *fs_info)
857 {
858 	return READ_ONCE(fs_info->last_root_drop_gen);
859 }
860 
861 /*
862  * Take the number of bytes to be checksummed and figure out how many leaves
863  * it would require to store the csums for that many bytes.
864  */
865 static inline u64 btrfs_csum_bytes_to_leaves(
866 			const struct btrfs_fs_info *fs_info, u64 csum_bytes)
867 {
868 	const u64 num_csums = csum_bytes >> fs_info->sectorsize_bits;
869 
870 	return DIV_ROUND_UP_ULL(num_csums, fs_info->csums_per_leaf);
871 }
872 
873 /*
874  * Use this if we would be adding new items, as we could split nodes as we cow
875  * down the tree.
876  */
877 static inline u64 btrfs_calc_insert_metadata_size(const struct btrfs_fs_info *fs_info,
878 						  unsigned num_items)
879 {
880 	return (u64)fs_info->nodesize * BTRFS_MAX_LEVEL * 2 * num_items;
881 }
882 
883 /*
884  * Doing a truncate or a modification won't result in new nodes or leaves, just
885  * what we need for COW.
886  */
887 static inline u64 btrfs_calc_metadata_size(const struct btrfs_fs_info *fs_info,
888 						 unsigned num_items)
889 {
890 	return (u64)fs_info->nodesize * BTRFS_MAX_LEVEL * num_items;
891 }
892 
893 #define BTRFS_MAX_EXTENT_ITEM_SIZE(r) ((BTRFS_LEAF_DATA_SIZE(r->fs_info) >> 4) - \
894 					sizeof(struct btrfs_item))
895 
896 static inline bool btrfs_is_zoned(const struct btrfs_fs_info *fs_info)
897 {
898 	return IS_ENABLED(CONFIG_BLK_DEV_ZONED) && fs_info->zone_size > 0;
899 }
900 
901 /*
902  * Count how many fs_info->max_extent_size cover the @size
903  */
904 static inline u32 count_max_extents(struct btrfs_fs_info *fs_info, u64 size)
905 {
906 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
907 	if (!fs_info)
908 		return div_u64(size + BTRFS_MAX_EXTENT_SIZE - 1, BTRFS_MAX_EXTENT_SIZE);
909 #endif
910 
911 	return div_u64(size + fs_info->max_extent_size - 1, fs_info->max_extent_size);
912 }
913 
914 bool btrfs_exclop_start(struct btrfs_fs_info *fs_info,
915 			enum btrfs_exclusive_operation type);
916 bool btrfs_exclop_start_try_lock(struct btrfs_fs_info *fs_info,
917 				 enum btrfs_exclusive_operation type);
918 void btrfs_exclop_start_unlock(struct btrfs_fs_info *fs_info);
919 void btrfs_exclop_finish(struct btrfs_fs_info *fs_info);
920 void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
921 			  enum btrfs_exclusive_operation op);
922 
923 /* Compatibility and incompatibility defines */
924 void __btrfs_set_fs_incompat(struct btrfs_fs_info *fs_info, u64 flag,
925 			     const char *name);
926 void __btrfs_clear_fs_incompat(struct btrfs_fs_info *fs_info, u64 flag,
927 			       const char *name);
928 void __btrfs_set_fs_compat_ro(struct btrfs_fs_info *fs_info, u64 flag,
929 			      const char *name);
930 void __btrfs_clear_fs_compat_ro(struct btrfs_fs_info *fs_info, u64 flag,
931 				const char *name);
932 
933 #define __btrfs_fs_incompat(fs_info, flags)				\
934 	(!!(btrfs_super_incompat_flags((fs_info)->super_copy) & (flags)))
935 
936 #define __btrfs_fs_compat_ro(fs_info, flags)				\
937 	(!!(btrfs_super_compat_ro_flags((fs_info)->super_copy) & (flags)))
938 
939 #define btrfs_set_fs_incompat(__fs_info, opt)				\
940 	__btrfs_set_fs_incompat((__fs_info), BTRFS_FEATURE_INCOMPAT_##opt, #opt)
941 
942 #define btrfs_clear_fs_incompat(__fs_info, opt)				\
943 	__btrfs_clear_fs_incompat((__fs_info), BTRFS_FEATURE_INCOMPAT_##opt, #opt)
944 
945 #define btrfs_fs_incompat(fs_info, opt)					\
946 	__btrfs_fs_incompat((fs_info), BTRFS_FEATURE_INCOMPAT_##opt)
947 
948 #define btrfs_set_fs_compat_ro(__fs_info, opt)				\
949 	__btrfs_set_fs_compat_ro((__fs_info), BTRFS_FEATURE_COMPAT_RO_##opt, #opt)
950 
951 #define btrfs_clear_fs_compat_ro(__fs_info, opt)			\
952 	__btrfs_clear_fs_compat_ro((__fs_info), BTRFS_FEATURE_COMPAT_RO_##opt, #opt)
953 
954 #define btrfs_fs_compat_ro(fs_info, opt)				\
955 	__btrfs_fs_compat_ro((fs_info), BTRFS_FEATURE_COMPAT_RO_##opt)
956 
957 #define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)
958 #define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)
959 #define btrfs_raw_test_opt(o, opt)	((o) & BTRFS_MOUNT_##opt)
960 #define btrfs_test_opt(fs_info, opt)	((fs_info)->mount_opt & \
961 					 BTRFS_MOUNT_##opt)
962 
963 #define btrfs_set_and_info(fs_info, opt, fmt, args...)			\
964 do {									\
965 	if (!btrfs_test_opt(fs_info, opt))				\
966 		btrfs_info(fs_info, fmt, ##args);			\
967 	btrfs_set_opt(fs_info->mount_opt, opt);				\
968 } while (0)
969 
970 #define btrfs_clear_and_info(fs_info, opt, fmt, args...)		\
971 do {									\
972 	if (btrfs_test_opt(fs_info, opt))				\
973 		btrfs_info(fs_info, fmt, ##args);			\
974 	btrfs_clear_opt(fs_info->mount_opt, opt);			\
975 } while (0)
976 
977 static inline int btrfs_fs_closing(struct btrfs_fs_info *fs_info)
978 {
979 	/* Do it this way so we only ever do one test_bit in the normal case. */
980 	if (test_bit(BTRFS_FS_CLOSING_START, &fs_info->flags)) {
981 		if (test_bit(BTRFS_FS_CLOSING_DONE, &fs_info->flags))
982 			return 2;
983 		return 1;
984 	}
985 	return 0;
986 }
987 
988 /*
989  * If we remount the fs to be R/O or umount the fs, the cleaner needn't do
990  * anything except sleeping. This function is used to check the status of
991  * the fs.
992  * We check for BTRFS_FS_STATE_RO to avoid races with a concurrent remount,
993  * since setting and checking for SB_RDONLY in the superblock's flags is not
994  * atomic.
995  */
996 static inline int btrfs_need_cleaner_sleep(struct btrfs_fs_info *fs_info)
997 {
998 	return test_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state) ||
999 		btrfs_fs_closing(fs_info);
1000 }
1001 
1002 static inline void btrfs_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
1003 {
1004 	clear_and_wake_up_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags);
1005 }
1006 
1007 #define BTRFS_FS_ERROR(fs_info)	(READ_ONCE((fs_info)->fs_error))
1008 
1009 #define BTRFS_FS_LOG_CLEANUP_ERROR(fs_info)				\
1010 	(unlikely(test_bit(BTRFS_FS_STATE_LOG_CLEANUP_ERROR,		\
1011 			   &(fs_info)->fs_state)))
1012 
1013 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
1014 
1015 #define EXPORT_FOR_TESTS
1016 
1017 static inline int btrfs_is_testing(struct btrfs_fs_info *fs_info)
1018 {
1019 	return test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state);
1020 }
1021 
1022 void btrfs_test_destroy_inode(struct inode *inode);
1023 
1024 #else
1025 
1026 #define EXPORT_FOR_TESTS static
1027 
1028 static inline int btrfs_is_testing(struct btrfs_fs_info *fs_info)
1029 {
1030 	return 0;
1031 }
1032 #endif
1033 
1034 #endif
1035