1 /* SPDX-License-Identifier: GPL-2.0 */
6 * SOME HIGH LEVEL CODE DOCUMENTATION:
8 * Bcache mostly works with cache sets, cache devices, and backing devices.
10 * Support for multiple cache devices hasn't quite been finished off yet, but
11 * it's about 95% plumbed through. A cache set and its cache devices is sort of
12 * like a md raid array and its component devices. Most of the code doesn't care
13 * about individual cache devices, the main abstraction is the cache set.
15 * Multiple cache devices is intended to give us the ability to mirror dirty
16 * cached data and metadata, without mirroring clean cached data.
18 * Backing devices are different, in that they have a lifetime independent of a
19 * cache set. When you register a newly formatted backing device it'll come up
20 * in passthrough mode, and then you can attach and detach a backing device from
21 * a cache set at runtime - while it's mounted and in use. Detaching implicitly
22 * invalidates any cached data for that backing device.
24 * A cache set can have multiple (many) backing devices attached to it.
26 * There's also flash only volumes - this is the reason for the distinction
27 * between struct cached_dev and struct bcache_device. A flash only volume
28 * works much like a bcache device that has a backing device, except the
29 * "cached" data is always dirty. The end result is that we get thin
30 * provisioning with very little additional code.
32 * Flash only volumes work but they're not production ready because the moving
33 * garbage collector needs more work. More on that later.
37 * Bcache is primarily designed for caching, which means that in normal
38 * operation all of our available space will be allocated. Thus, we need an
39 * efficient way of deleting things from the cache so we can write new things to
42 * To do this, we first divide the cache device up into buckets. A bucket is the
43 * unit of allocation; they're typically around 1 mb - anywhere from 128k to 2M+
46 * Each bucket has a 16 bit priority, and an 8 bit generation associated with
47 * it. The gens and priorities for all the buckets are stored contiguously and
48 * packed on disk (in a linked list of buckets - aside from the superblock, all
49 * of bcache's metadata is stored in buckets).
51 * The priority is used to implement an LRU. We reset a bucket's priority when
52 * we allocate it or on cache it, and every so often we decrement the priority
53 * of each bucket. It could be used to implement something more sophisticated,
54 * if anyone ever gets around to it.
56 * The generation is used for invalidating buckets. Each pointer also has an 8
57 * bit generation embedded in it; for a pointer to be considered valid, its gen
58 * must match the gen of the bucket it points into. Thus, to reuse a bucket all
59 * we have to do is increment its gen (and write its new gen to disk; we batch
62 * Bcache is entirely COW - we never write twice to a bucket, even buckets that
63 * contain metadata (including btree nodes).
67 * Bcache is in large part design around the btree.
69 * At a high level, the btree is just an index of key -> ptr tuples.
71 * Keys represent extents, and thus have a size field. Keys also have a variable
72 * number of pointers attached to them (potentially zero, which is handy for
73 * invalidating the cache).
75 * The key itself is an inode:offset pair. The inode number corresponds to a
76 * backing device or a flash only volume. The offset is the ending offset of the
77 * extent within the inode - not the starting offset; this makes lookups
78 * slightly more convenient.
80 * Pointers contain the cache device id, the offset on that device, and an 8 bit
81 * generation number. More on the gen later.
83 * Index lookups are not fully abstracted - cache lookups in particular are
84 * still somewhat mixed in with the btree code, but things are headed in that
87 * Updates are fairly well abstracted, though. There are two different ways of
88 * updating the btree; insert and replace.
90 * BTREE_INSERT will just take a list of keys and insert them into the btree -
91 * overwriting (possibly only partially) any extents they overlap with. This is
92 * used to update the index after a write.
94 * BTREE_REPLACE is really cmpxchg(); it inserts a key into the btree iff it is
95 * overwriting a key that matches another given key. This is used for inserting
96 * data into the cache after a cache miss, and for background writeback, and for
97 * the moving garbage collector.
99 * There is no "delete" operation; deleting things from the index is
100 * accomplished by either by invalidating pointers (by incrementing a bucket's
101 * gen) or by inserting a key with 0 pointers - which will overwrite anything
102 * previously present at that location in the index.
104 * This means that there are always stale/invalid keys in the btree. They're
105 * filtered out by the code that iterates through a btree node, and removed when
106 * a btree node is rewritten.
110 * Our unit of allocation is a bucket, and we we can't arbitrarily allocate and
111 * free smaller than a bucket - so, that's how big our btree nodes are.
113 * (If buckets are really big we'll only use part of the bucket for a btree node
114 * - no less than 1/4th - but a bucket still contains no more than a single
115 * btree node. I'd actually like to change this, but for now we rely on the
116 * bucket's gen for deleting btree nodes when we rewrite/split a node.)
118 * Anyways, btree nodes are big - big enough to be inefficient with a textbook
119 * btree implementation.
121 * The way this is solved is that btree nodes are internally log structured; we
122 * can append new keys to an existing btree node without rewriting it. This
123 * means each set of keys we write is sorted, but the node is not.
125 * We maintain this log structure in memory - keeping 1Mb of keys sorted would
126 * be expensive, and we have to distinguish between the keys we have written and
127 * the keys we haven't. So to do a lookup in a btree node, we have to search
128 * each sorted set. But we do merge written sets together lazily, so the cost of
129 * these extra searches is quite low (normally most of the keys in a btree node
130 * will be in one big set, and then there'll be one or two sets that are much
133 * This log structure makes bcache's btree more of a hybrid between a
134 * conventional btree and a compacting data structure, with some of the
135 * advantages of both.
137 * GARBAGE COLLECTION:
139 * We can't just invalidate any bucket - it might contain dirty data or
140 * metadata. If it once contained dirty data, other writes might overwrite it
141 * later, leaving no valid pointers into that bucket in the index.
143 * Thus, the primary purpose of garbage collection is to find buckets to reuse.
144 * It also counts how much valid data it each bucket currently contains, so that
145 * allocation can reuse buckets sooner when they've been mostly overwritten.
147 * It also does some things that are really internal to the btree
148 * implementation. If a btree node contains pointers that are stale by more than
149 * some threshold, it rewrites the btree node to avoid the bucket's generation
150 * wrapping around. It also merges adjacent btree nodes if they're empty enough.
154 * Bcache's journal is not necessary for consistency; we always strictly
155 * order metadata writes so that the btree and everything else is consistent on
156 * disk in the event of an unclean shutdown, and in fact bcache had writeback
157 * caching (with recovery from unclean shutdown) before journalling was
160 * Rather, the journal is purely a performance optimization; we can't complete a
161 * write until we've updated the index on disk, otherwise the cache would be
162 * inconsistent in the event of an unclean shutdown. This means that without the
163 * journal, on random write workloads we constantly have to update all the leaf
164 * nodes in the btree, and those writes will be mostly empty (appending at most
165 * a few keys each) - highly inefficient in terms of amount of metadata writes,
166 * and it puts more strain on the various btree resorting/compacting code.
168 * The journal is just a log of keys we've inserted; on startup we just reinsert
169 * all the keys in the open journal entries. That means that when we're updating
170 * a node in the btree, we can wait until a 4k block of keys fills up before
173 * For simplicity, we only journal updates to leaf nodes; updates to parent
174 * nodes are rare enough (since our leaf nodes are huge) that it wasn't worth
175 * the complexity to deal with journalling them (in particular, journal replay)
176 * - updates to non leaf nodes just happen synchronously (see btree_split()).
179 #define pr_fmt(fmt) "bcache: %s() " fmt "\n", __func__
181 #include <linux/bcache.h>
182 #include <linux/bio.h>
183 #include <linux/kobject.h>
184 #include <linux/list.h>
185 #include <linux/mutex.h>
186 #include <linux/rbtree.h>
187 #include <linux/rwsem.h>
188 #include <linux/types.h>
189 #include <linux/workqueue.h>
199 uint8_t last_gc
; /* Most out of date gen in the btree */
200 uint16_t gc_mark
; /* Bitfield used by GC. See below for field */
204 * I'd use bitfields for these, but I don't trust the compiler not to screw me
205 * as multiple threads touch struct bucket without locking
208 BITMASK(GC_MARK
, struct bucket
, gc_mark
, 0, 2);
209 #define GC_MARK_RECLAIMABLE 1
210 #define GC_MARK_DIRTY 2
211 #define GC_MARK_METADATA 3
212 #define GC_SECTORS_USED_SIZE 13
213 #define MAX_GC_SECTORS_USED (~(~0ULL << GC_SECTORS_USED_SIZE))
214 BITMASK(GC_SECTORS_USED
, struct bucket
, gc_mark
, 2, GC_SECTORS_USED_SIZE
);
215 BITMASK(GC_MOVE
, struct bucket
, gc_mark
, 15, 1);
230 struct bkey last_scanned
;
234 * Beginning and end of range in rb tree - so that we can skip taking
235 * lock and checking the rb tree when we need to check for overlapping
243 #define KEYBUF_NR 500
244 DECLARE_ARRAY_ALLOCATOR(struct keybuf_key
, freelist
, KEYBUF_NR
);
247 struct bcache_device
{
254 #define BCACHEDEVNAME_SIZE 12
255 char name
[BCACHEDEVNAME_SIZE
];
257 struct gendisk
*disk
;
260 #define BCACHE_DEV_CLOSING 0
261 #define BCACHE_DEV_DETACHING 1
262 #define BCACHE_DEV_UNLINK_DONE 2
265 unsigned stripe_size
;
266 atomic_t
*stripe_sectors_dirty
;
267 unsigned long *full_dirty_stripes
;
269 unsigned long sectors_dirty_last
;
270 long sectors_dirty_derivative
;
272 struct bio_set
*bio_split
;
274 unsigned data_csum
:1;
276 int (*cache_miss
)(struct btree
*, struct search
*,
277 struct bio
*, unsigned);
278 int (*ioctl
) (struct bcache_device
*, fmode_t
, unsigned, unsigned long);
282 /* Used to track sequential IO so it can be skipped */
283 struct hlist_node hash
;
284 struct list_head lru
;
286 unsigned long jiffies
;
292 struct list_head list
;
293 struct bcache_device disk
;
294 struct block_device
*bdev
;
298 struct bio_vec sb_bv
[1];
299 struct closure sb_write
;
300 struct semaphore sb_write_mutex
;
302 /* Refcount on the cache set. Always nonzero when we're caching. */
304 struct work_struct detach
;
307 * Device might not be running if it's dirty and the cache set hasn't
313 * Writes take a shared lock from start to finish; scanning for dirty
314 * data to refill the rb tree requires an exclusive lock.
316 struct rw_semaphore writeback_lock
;
319 * Nonzero, and writeback has a refcount (d->count), iff there is dirty
320 * data in the cache. Protected by writeback_lock; must have an
321 * shared lock to set and exclusive lock to clear.
325 struct bch_ratelimit writeback_rate
;
326 struct delayed_work writeback_rate_update
;
329 * Internal to the writeback code, so read_dirty() can keep track of
334 /* Limit number of writeback bios in flight */
335 struct semaphore in_flight
;
336 struct task_struct
*writeback_thread
;
337 struct workqueue_struct
*writeback_write_wq
;
339 struct keybuf writeback_keys
;
341 /* For tracking sequential IO */
342 #define RECENT_IO_BITS 7
343 #define RECENT_IO (1 << RECENT_IO_BITS)
344 struct io io
[RECENT_IO
];
345 struct hlist_head io_hash
[RECENT_IO
+ 1];
346 struct list_head io_lru
;
349 struct cache_accounting accounting
;
351 /* The rest of this all shows up in sysfs */
352 unsigned sequential_cutoff
;
356 unsigned bypass_torture_test
:1;
358 unsigned partial_stripes_expensive
:1;
359 unsigned writeback_metadata
:1;
360 unsigned writeback_running
:1;
361 unsigned char writeback_percent
;
362 unsigned writeback_delay
;
364 uint64_t writeback_rate_target
;
365 int64_t writeback_rate_proportional
;
366 int64_t writeback_rate_derivative
;
367 int64_t writeback_rate_change
;
369 unsigned writeback_rate_update_seconds
;
370 unsigned writeback_rate_d_term
;
371 unsigned writeback_rate_p_term_inverse
;
383 struct cache_set
*set
;
386 struct bio_vec sb_bv
[1];
389 struct block_device
*bdev
;
391 struct task_struct
*alloc_thread
;
394 struct prio_set
*disk_buckets
;
397 * When allocating new buckets, prio_write() gets first dibs - since we
398 * may not be allocate at all without writing priorities and gens.
399 * prio_buckets[] contains the last buckets we wrote priorities to (so
400 * gc can mark them as metadata), prio_next[] contains the buckets
401 * allocated for the next prio write.
403 uint64_t *prio_buckets
;
404 uint64_t *prio_last_buckets
;
407 * free: Buckets that are ready to be used
409 * free_inc: Incoming buckets - these are buckets that currently have
410 * cached data in them, and we can't reuse them until after we write
411 * their new gen to disk. After prio_write() finishes writing the new
412 * gens/prios, they'll be moved to the free list (and possibly discarded
415 DECLARE_FIFO(long, free
)[RESERVE_NR
];
416 DECLARE_FIFO(long, free_inc
);
418 size_t fifo_last_bucket
;
420 /* Allocation stuff: */
421 struct bucket
*buckets
;
423 DECLARE_HEAP(struct bucket
*, heap
);
426 * If nonzero, we know we aren't going to find any buckets to invalidate
427 * until a gc finishes - otherwise we could pointlessly burn a ton of
430 unsigned invalidate_needs_gc
;
432 bool discard
; /* Get rid of? */
434 struct journal_device journal
;
436 /* The rest of this all shows up in sysfs */
437 #define IO_ERROR_SHIFT 20
441 atomic_long_t meta_sectors_written
;
442 atomic_long_t btree_sectors_written
;
443 atomic_long_t sectors_written
;
451 uint64_t data
; /* sectors */
452 unsigned in_use
; /* percent */
456 * Flag bits, for how the cache set is shutting down, and what phase it's at:
458 * CACHE_SET_UNREGISTERING means we're not just shutting down, we're detaching
459 * all the backing devices first (their cached data gets invalidated, and they
460 * won't automatically reattach).
462 * CACHE_SET_STOPPING always gets set first when we're closing down a cache set;
463 * we'll continue to run normally for awhile with CACHE_SET_STOPPING set (i.e.
464 * flushing dirty data).
466 * CACHE_SET_RUNNING means all cache devices have been registered and journal
467 * replay is complete.
469 #define CACHE_SET_UNREGISTERING 0
470 #define CACHE_SET_STOPPING 1
471 #define CACHE_SET_RUNNING 2
476 struct list_head list
;
478 struct kobject internal
;
479 struct dentry
*debug
;
480 struct cache_accounting accounting
;
486 struct cache
*cache
[MAX_CACHES_PER_SET
];
487 struct cache
*cache_by_alloc
[MAX_CACHES_PER_SET
];
490 struct bcache_device
**devices
;
491 struct list_head cached_devs
;
492 uint64_t cached_dev_sectors
;
493 struct closure caching
;
495 struct closure sb_write
;
496 struct semaphore sb_write_mutex
;
500 struct bio_set
*bio_split
;
502 /* For the btree cache */
503 struct shrinker shrink
;
505 /* For the btree cache and anything allocation related */
506 struct mutex bucket_lock
;
508 /* log2(bucket_size), in sectors */
509 unsigned short bucket_bits
;
511 /* log2(block_size), in sectors */
512 unsigned short block_bits
;
515 * Default number of pages for a new btree node - may be less than a
518 unsigned btree_pages
;
521 * Lists of struct btrees; lru is the list for structs that have memory
522 * allocated for actual btree node, freed is for structs that do not.
524 * We never free a struct btree, except on shutdown - we just put it on
525 * the btree_cache_freed list and reuse it later. This simplifies the
526 * code, and it doesn't cost us much memory as the memory usage is
527 * dominated by buffers that hold the actual btree node data and those
528 * can be freed - and the number of struct btrees allocated is
529 * effectively bounded.
531 * btree_cache_freeable effectively is a small cache - we use it because
532 * high order page allocations can be rather expensive, and it's quite
533 * common to delete and allocate btree nodes in quick succession. It
534 * should never grow past ~2-3 nodes in practice.
536 struct list_head btree_cache
;
537 struct list_head btree_cache_freeable
;
538 struct list_head btree_cache_freed
;
540 /* Number of elements in btree_cache + btree_cache_freeable lists */
541 unsigned btree_cache_used
;
544 * If we need to allocate memory for a new btree node and that
545 * allocation fails, we can cannibalize another node in the btree cache
546 * to satisfy the allocation - lock to guarantee only one thread does
549 wait_queue_head_t btree_cache_wait
;
550 struct task_struct
*btree_cache_alloc_lock
;
553 * When we free a btree node, we increment the gen of the bucket the
554 * node is in - but we can't rewrite the prios and gens until we
555 * finished whatever it is we were doing, otherwise after a crash the
556 * btree node would be freed but for say a split, we might not have the
557 * pointers to the new nodes inserted into the btree yet.
559 * This is a refcount that blocks prio_write() until the new keys are
562 atomic_t prio_blocked
;
563 wait_queue_head_t bucket_wait
;
566 * For any bio we don't skip we subtract the number of sectors from
567 * rescale; when it hits 0 we rescale all the bucket priorities.
571 * When we invalidate buckets, we use both the priority and the amount
572 * of good data to determine which buckets to reuse first - to weight
573 * those together consistently we keep track of the smallest nonzero
574 * priority of any bucket.
579 * max(gen - last_gc) for all buckets. When it gets too big we have to gc
580 * to keep gens from wrapping around.
583 struct gc_stat gc_stats
;
586 struct task_struct
*gc_thread
;
587 /* Where in the btree gc currently is */
591 * The allocation code needs gc_mark in struct bucket to be correct, but
592 * it's not while a gc is in progress. Protected by bucket_lock.
596 /* Counts how many sectors bio_insert has added to the cache */
597 atomic_t sectors_to_gc
;
598 wait_queue_head_t gc_wait
;
600 struct keybuf moving_gc_keys
;
601 /* Number of moving GC bios in flight */
602 struct semaphore moving_in_flight
;
604 struct workqueue_struct
*moving_gc_wq
;
608 #ifdef CONFIG_BCACHE_DEBUG
609 struct btree
*verify_data
;
610 struct bset
*verify_ondisk
;
611 struct mutex verify_lock
;
615 struct uuid_entry
*uuids
;
616 BKEY_PADDED(uuid_bucket
);
617 struct closure uuid_write
;
618 struct semaphore uuid_write_mutex
;
621 * A btree node on disk could have too many bsets for an iterator to fit
622 * on the stack - have to dynamically allocate them
624 mempool_t
*fill_iter
;
626 struct bset_sort_state sort
;
628 /* List of buckets we're currently writing data to */
629 struct list_head data_buckets
;
630 spinlock_t data_bucket_lock
;
632 struct journal journal
;
634 #define CONGESTED_MAX 1024
635 unsigned congested_last_us
;
638 /* The rest of this all shows up in sysfs */
639 unsigned congested_read_threshold_us
;
640 unsigned congested_write_threshold_us
;
642 struct time_stats btree_gc_time
;
643 struct time_stats btree_split_time
;
644 struct time_stats btree_read_time
;
646 atomic_long_t cache_read_races
;
647 atomic_long_t writeback_keys_done
;
648 atomic_long_t writeback_keys_failed
;
654 unsigned error_limit
;
655 unsigned error_decay
;
657 unsigned short journal_delay_ms
;
658 bool expensive_debug_checks
;
660 unsigned key_merging_disabled
:1;
661 unsigned gc_always_rewrite
:1;
662 unsigned shrinker_disabled
:1;
663 unsigned copy_gc_enabled
:1;
665 #define BUCKET_HASH_BITS 12
666 struct hlist_head bucket_hash
[1 << BUCKET_HASH_BITS
];
670 unsigned submit_time_us
;
675 * We only need pad = 3 here because we only ever carry around a
676 * single pointer - i.e. the pointer we're doing io to/from.
682 #define BTREE_PRIO USHRT_MAX
683 #define INITIAL_PRIO 32768U
685 #define btree_bytes(c) ((c)->btree_pages * PAGE_SIZE)
686 #define btree_blocks(b) \
687 ((unsigned) (KEY_SIZE(&b->key) >> (b)->c->block_bits))
689 #define btree_default_blocks(c) \
690 ((unsigned) ((PAGE_SECTORS * (c)->btree_pages) >> (c)->block_bits))
692 #define bucket_pages(c) ((c)->sb.bucket_size / PAGE_SECTORS)
693 #define bucket_bytes(c) ((c)->sb.bucket_size << 9)
694 #define block_bytes(c) ((c)->sb.block_size << 9)
696 #define prios_per_bucket(c) \
697 ((bucket_bytes(c) - sizeof(struct prio_set)) / \
698 sizeof(struct bucket_disk))
699 #define prio_buckets(c) \
700 DIV_ROUND_UP((size_t) (c)->sb.nbuckets, prios_per_bucket(c))
702 static inline size_t sector_to_bucket(struct cache_set
*c
, sector_t s
)
704 return s
>> c
->bucket_bits
;
707 static inline sector_t
bucket_to_sector(struct cache_set
*c
, size_t b
)
709 return ((sector_t
) b
) << c
->bucket_bits
;
712 static inline sector_t
bucket_remainder(struct cache_set
*c
, sector_t s
)
714 return s
& (c
->sb
.bucket_size
- 1);
717 static inline struct cache
*PTR_CACHE(struct cache_set
*c
,
718 const struct bkey
*k
,
721 return c
->cache
[PTR_DEV(k
, ptr
)];
724 static inline size_t PTR_BUCKET_NR(struct cache_set
*c
,
725 const struct bkey
*k
,
728 return sector_to_bucket(c
, PTR_OFFSET(k
, ptr
));
731 static inline struct bucket
*PTR_BUCKET(struct cache_set
*c
,
732 const struct bkey
*k
,
735 return PTR_CACHE(c
, k
, ptr
)->buckets
+ PTR_BUCKET_NR(c
, k
, ptr
);
738 static inline uint8_t gen_after(uint8_t a
, uint8_t b
)
741 return r
> 128U ? 0 : r
;
744 static inline uint8_t ptr_stale(struct cache_set
*c
, const struct bkey
*k
,
747 return gen_after(PTR_BUCKET(c
, k
, i
)->gen
, PTR_GEN(k
, i
));
750 static inline bool ptr_available(struct cache_set
*c
, const struct bkey
*k
,
753 return (PTR_DEV(k
, i
) < MAX_CACHES_PER_SET
) && PTR_CACHE(c
, k
, i
);
756 /* Btree key macros */
759 * This is used for various on disk data structures - cache_sb, prio_set, bset,
760 * jset: The checksum is _always_ the first 8 bytes of these structs
762 #define csum_set(i) \
763 bch_crc64(((void *) (i)) + sizeof(uint64_t), \
764 ((void *) bset_bkey_last(i)) - \
765 (((void *) (i)) + sizeof(uint64_t)))
767 /* Error handling macros */
769 #define btree_bug(b, ...) \
771 if (bch_cache_set_error((b)->c, __VA_ARGS__)) \
775 #define cache_bug(c, ...) \
777 if (bch_cache_set_error(c, __VA_ARGS__)) \
781 #define btree_bug_on(cond, b, ...) \
784 btree_bug(b, __VA_ARGS__); \
787 #define cache_bug_on(cond, c, ...) \
790 cache_bug(c, __VA_ARGS__); \
793 #define cache_set_err_on(cond, c, ...) \
796 bch_cache_set_error(c, __VA_ARGS__); \
801 #define for_each_cache(ca, cs, iter) \
802 for (iter = 0; ca = cs->cache[iter], iter < (cs)->sb.nr_in_set; iter++)
804 #define for_each_bucket(b, ca) \
805 for (b = (ca)->buckets + (ca)->sb.first_bucket; \
806 b < (ca)->buckets + (ca)->sb.nbuckets; b++)
808 static inline void cached_dev_put(struct cached_dev
*dc
)
810 if (atomic_dec_and_test(&dc
->count
))
811 schedule_work(&dc
->detach
);
814 static inline bool cached_dev_get(struct cached_dev
*dc
)
816 if (!atomic_inc_not_zero(&dc
->count
))
819 /* Paired with the mb in cached_dev_attach */
820 smp_mb__after_atomic();
825 * bucket_gc_gen() returns the difference between the bucket's current gen and
826 * the oldest gen of any pointer into that bucket in the btree (last_gc).
829 static inline uint8_t bucket_gc_gen(struct bucket
*b
)
831 return b
->gen
- b
->last_gc
;
834 #define BUCKET_GC_GEN_MAX 96U
836 #define kobj_attribute_write(n, fn) \
837 static struct kobj_attribute ksysfs_##n = __ATTR(n, S_IWUSR, NULL, fn)
839 #define kobj_attribute_rw(n, show, store) \
840 static struct kobj_attribute ksysfs_##n = \
841 __ATTR(n, S_IWUSR|S_IRUSR, show, store)
843 static inline void wake_up_allocators(struct cache_set
*c
)
848 for_each_cache(ca
, c
, i
)
849 wake_up_process(ca
->alloc_thread
);
852 /* Forward declarations */
854 void bch_count_io_errors(struct cache
*, blk_status_t
, const char *);
855 void bch_bbio_count_io_errors(struct cache_set
*, struct bio
*,
856 blk_status_t
, const char *);
857 void bch_bbio_endio(struct cache_set
*, struct bio
*, blk_status_t
,
859 void bch_bbio_free(struct bio
*, struct cache_set
*);
860 struct bio
*bch_bbio_alloc(struct cache_set
*);
862 void __bch_submit_bbio(struct bio
*, struct cache_set
*);
863 void bch_submit_bbio(struct bio
*, struct cache_set
*, struct bkey
*, unsigned);
865 uint8_t bch_inc_gen(struct cache
*, struct bucket
*);
866 void bch_rescale_priorities(struct cache_set
*, int);
868 bool bch_can_invalidate_bucket(struct cache
*, struct bucket
*);
869 void __bch_invalidate_one_bucket(struct cache
*, struct bucket
*);
871 void __bch_bucket_free(struct cache
*, struct bucket
*);
872 void bch_bucket_free(struct cache_set
*, struct bkey
*);
874 long bch_bucket_alloc(struct cache
*, unsigned, bool);
875 int __bch_bucket_alloc_set(struct cache_set
*, unsigned,
876 struct bkey
*, int, bool);
877 int bch_bucket_alloc_set(struct cache_set
*, unsigned,
878 struct bkey
*, int, bool);
879 bool bch_alloc_sectors(struct cache_set
*, struct bkey
*, unsigned,
880 unsigned, unsigned, bool);
883 bool bch_cache_set_error(struct cache_set
*, const char *, ...);
885 void bch_prio_write(struct cache
*);
886 void bch_write_bdev_super(struct cached_dev
*, struct closure
*);
888 extern struct workqueue_struct
*bcache_wq
;
889 extern const char * const bch_cache_modes
[];
890 extern struct mutex bch_register_lock
;
891 extern struct list_head bch_cache_sets
;
893 extern struct kobj_type bch_cached_dev_ktype
;
894 extern struct kobj_type bch_flash_dev_ktype
;
895 extern struct kobj_type bch_cache_set_ktype
;
896 extern struct kobj_type bch_cache_set_internal_ktype
;
897 extern struct kobj_type bch_cache_ktype
;
899 void bch_cached_dev_release(struct kobject
*);
900 void bch_flash_dev_release(struct kobject
*);
901 void bch_cache_set_release(struct kobject
*);
902 void bch_cache_release(struct kobject
*);
904 int bch_uuid_write(struct cache_set
*);
905 void bcache_write_super(struct cache_set
*);
907 int bch_flash_dev_create(struct cache_set
*c
, uint64_t size
);
909 int bch_cached_dev_attach(struct cached_dev
*, struct cache_set
*);
910 void bch_cached_dev_detach(struct cached_dev
*);
911 void bch_cached_dev_run(struct cached_dev
*);
912 void bcache_device_stop(struct bcache_device
*);
914 void bch_cache_set_unregister(struct cache_set
*);
915 void bch_cache_set_stop(struct cache_set
*);
917 struct cache_set
*bch_cache_set_alloc(struct cache_sb
*);
918 void bch_btree_cache_free(struct cache_set
*);
919 int bch_btree_cache_alloc(struct cache_set
*);
920 void bch_moving_init_cache_set(struct cache_set
*);
921 int bch_open_buckets_alloc(struct cache_set
*);
922 void bch_open_buckets_free(struct cache_set
*);
924 int bch_cache_allocator_start(struct cache
*ca
);
926 void bch_debug_exit(void);
927 int bch_debug_init(struct kobject
*);
928 void bch_request_exit(void);
929 int bch_request_init(void);
931 #endif /* _BCACHE_H */