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1 | #ifndef _BCACHE_H |
2 | #define _BCACHE_H | |
3 | ||
4 | /* | |
5 | * SOME HIGH LEVEL CODE DOCUMENTATION: | |
6 | * | |
7 | * Bcache mostly works with cache sets, cache devices, and backing devices. | |
8 | * | |
9 | * Support for multiple cache devices hasn't quite been finished off yet, but | |
10 | * it's about 95% plumbed through. A cache set and its cache devices is sort of | |
11 | * like a md raid array and its component devices. Most of the code doesn't care | |
12 | * about individual cache devices, the main abstraction is the cache set. | |
13 | * | |
14 | * Multiple cache devices is intended to give us the ability to mirror dirty | |
15 | * cached data and metadata, without mirroring clean cached data. | |
16 | * | |
17 | * Backing devices are different, in that they have a lifetime independent of a | |
18 | * cache set. When you register a newly formatted backing device it'll come up | |
19 | * in passthrough mode, and then you can attach and detach a backing device from | |
20 | * a cache set at runtime - while it's mounted and in use. Detaching implicitly | |
21 | * invalidates any cached data for that backing device. | |
22 | * | |
23 | * A cache set can have multiple (many) backing devices attached to it. | |
24 | * | |
25 | * There's also flash only volumes - this is the reason for the distinction | |
26 | * between struct cached_dev and struct bcache_device. A flash only volume | |
27 | * works much like a bcache device that has a backing device, except the | |
28 | * "cached" data is always dirty. The end result is that we get thin | |
29 | * provisioning with very little additional code. | |
30 | * | |
31 | * Flash only volumes work but they're not production ready because the moving | |
32 | * garbage collector needs more work. More on that later. | |
33 | * | |
34 | * BUCKETS/ALLOCATION: | |
35 | * | |
36 | * Bcache is primarily designed for caching, which means that in normal | |
37 | * operation all of our available space will be allocated. Thus, we need an | |
38 | * efficient way of deleting things from the cache so we can write new things to | |
39 | * it. | |
40 | * | |
41 | * To do this, we first divide the cache device up into buckets. A bucket is the | |
42 | * unit of allocation; they're typically around 1 mb - anywhere from 128k to 2M+ | |
43 | * works efficiently. | |
44 | * | |
45 | * Each bucket has a 16 bit priority, and an 8 bit generation associated with | |
46 | * it. The gens and priorities for all the buckets are stored contiguously and | |
47 | * packed on disk (in a linked list of buckets - aside from the superblock, all | |
48 | * of bcache's metadata is stored in buckets). | |
49 | * | |
50 | * The priority is used to implement an LRU. We reset a bucket's priority when | |
51 | * we allocate it or on cache it, and every so often we decrement the priority | |
52 | * of each bucket. It could be used to implement something more sophisticated, | |
53 | * if anyone ever gets around to it. | |
54 | * | |
55 | * The generation is used for invalidating buckets. Each pointer also has an 8 | |
56 | * bit generation embedded in it; for a pointer to be considered valid, its gen | |
57 | * must match the gen of the bucket it points into. Thus, to reuse a bucket all | |
58 | * we have to do is increment its gen (and write its new gen to disk; we batch | |
59 | * this up). | |
60 | * | |
61 | * Bcache is entirely COW - we never write twice to a bucket, even buckets that | |
62 | * contain metadata (including btree nodes). | |
63 | * | |
64 | * THE BTREE: | |
65 | * | |
66 | * Bcache is in large part design around the btree. | |
67 | * | |
68 | * At a high level, the btree is just an index of key -> ptr tuples. | |
69 | * | |
70 | * Keys represent extents, and thus have a size field. Keys also have a variable | |
71 | * number of pointers attached to them (potentially zero, which is handy for | |
72 | * invalidating the cache). | |
73 | * | |
74 | * The key itself is an inode:offset pair. The inode number corresponds to a | |
75 | * backing device or a flash only volume. The offset is the ending offset of the | |
76 | * extent within the inode - not the starting offset; this makes lookups | |
77 | * slightly more convenient. | |
78 | * | |
79 | * Pointers contain the cache device id, the offset on that device, and an 8 bit | |
80 | * generation number. More on the gen later. | |
81 | * | |
82 | * Index lookups are not fully abstracted - cache lookups in particular are | |
83 | * still somewhat mixed in with the btree code, but things are headed in that | |
84 | * direction. | |
85 | * | |
86 | * Updates are fairly well abstracted, though. There are two different ways of | |
87 | * updating the btree; insert and replace. | |
88 | * | |
89 | * BTREE_INSERT will just take a list of keys and insert them into the btree - | |
90 | * overwriting (possibly only partially) any extents they overlap with. This is | |
91 | * used to update the index after a write. | |
92 | * | |
93 | * BTREE_REPLACE is really cmpxchg(); it inserts a key into the btree iff it is | |
94 | * overwriting a key that matches another given key. This is used for inserting | |
95 | * data into the cache after a cache miss, and for background writeback, and for | |
96 | * the moving garbage collector. | |
97 | * | |
98 | * There is no "delete" operation; deleting things from the index is | |
99 | * accomplished by either by invalidating pointers (by incrementing a bucket's | |
100 | * gen) or by inserting a key with 0 pointers - which will overwrite anything | |
101 | * previously present at that location in the index. | |
102 | * | |
103 | * This means that there are always stale/invalid keys in the btree. They're | |
104 | * filtered out by the code that iterates through a btree node, and removed when | |
105 | * a btree node is rewritten. | |
106 | * | |
107 | * BTREE NODES: | |
108 | * | |
109 | * Our unit of allocation is a bucket, and we we can't arbitrarily allocate and | |
110 | * free smaller than a bucket - so, that's how big our btree nodes are. | |
111 | * | |
112 | * (If buckets are really big we'll only use part of the bucket for a btree node | |
113 | * - no less than 1/4th - but a bucket still contains no more than a single | |
114 | * btree node. I'd actually like to change this, but for now we rely on the | |
115 | * bucket's gen for deleting btree nodes when we rewrite/split a node.) | |
116 | * | |
117 | * Anyways, btree nodes are big - big enough to be inefficient with a textbook | |
118 | * btree implementation. | |
119 | * | |
120 | * The way this is solved is that btree nodes are internally log structured; we | |
121 | * can append new keys to an existing btree node without rewriting it. This | |
122 | * means each set of keys we write is sorted, but the node is not. | |
123 | * | |
124 | * We maintain this log structure in memory - keeping 1Mb of keys sorted would | |
125 | * be expensive, and we have to distinguish between the keys we have written and | |
126 | * the keys we haven't. So to do a lookup in a btree node, we have to search | |
127 | * each sorted set. But we do merge written sets together lazily, so the cost of | |
128 | * these extra searches is quite low (normally most of the keys in a btree node | |
129 | * will be in one big set, and then there'll be one or two sets that are much | |
130 | * smaller). | |
131 | * | |
132 | * This log structure makes bcache's btree more of a hybrid between a | |
133 | * conventional btree and a compacting data structure, with some of the | |
134 | * advantages of both. | |
135 | * | |
136 | * GARBAGE COLLECTION: | |
137 | * | |
138 | * We can't just invalidate any bucket - it might contain dirty data or | |
139 | * metadata. If it once contained dirty data, other writes might overwrite it | |
140 | * later, leaving no valid pointers into that bucket in the index. | |
141 | * | |
142 | * Thus, the primary purpose of garbage collection is to find buckets to reuse. | |
143 | * It also counts how much valid data it each bucket currently contains, so that | |
144 | * allocation can reuse buckets sooner when they've been mostly overwritten. | |
145 | * | |
146 | * It also does some things that are really internal to the btree | |
147 | * implementation. If a btree node contains pointers that are stale by more than | |
148 | * some threshold, it rewrites the btree node to avoid the bucket's generation | |
149 | * wrapping around. It also merges adjacent btree nodes if they're empty enough. | |
150 | * | |
151 | * THE JOURNAL: | |
152 | * | |
153 | * Bcache's journal is not necessary for consistency; we always strictly | |
154 | * order metadata writes so that the btree and everything else is consistent on | |
155 | * disk in the event of an unclean shutdown, and in fact bcache had writeback | |
156 | * caching (with recovery from unclean shutdown) before journalling was | |
157 | * implemented. | |
158 | * | |
159 | * Rather, the journal is purely a performance optimization; we can't complete a | |
160 | * write until we've updated the index on disk, otherwise the cache would be | |
161 | * inconsistent in the event of an unclean shutdown. This means that without the | |
162 | * journal, on random write workloads we constantly have to update all the leaf | |
163 | * nodes in the btree, and those writes will be mostly empty (appending at most | |
164 | * a few keys each) - highly inefficient in terms of amount of metadata writes, | |
165 | * and it puts more strain on the various btree resorting/compacting code. | |
166 | * | |
167 | * The journal is just a log of keys we've inserted; on startup we just reinsert | |
168 | * all the keys in the open journal entries. That means that when we're updating | |
169 | * a node in the btree, we can wait until a 4k block of keys fills up before | |
170 | * writing them out. | |
171 | * | |
172 | * For simplicity, we only journal updates to leaf nodes; updates to parent | |
173 | * nodes are rare enough (since our leaf nodes are huge) that it wasn't worth | |
174 | * the complexity to deal with journalling them (in particular, journal replay) | |
175 | * - updates to non leaf nodes just happen synchronously (see btree_split()). | |
176 | */ | |
177 | ||
178 | #define pr_fmt(fmt) "bcache: %s() " fmt "\n", __func__ | |
179 | ||
180 | #include <linux/bio.h> | |
181 | #include <linux/blktrace_api.h> | |
182 | #include <linux/kobject.h> | |
183 | #include <linux/list.h> | |
184 | #include <linux/mutex.h> | |
185 | #include <linux/rbtree.h> | |
186 | #include <linux/rwsem.h> | |
187 | #include <linux/types.h> | |
188 | #include <linux/workqueue.h> | |
189 | ||
190 | #include "util.h" | |
191 | #include "closure.h" | |
192 | ||
193 | struct bucket { | |
194 | atomic_t pin; | |
195 | uint16_t prio; | |
196 | uint8_t gen; | |
197 | uint8_t disk_gen; | |
198 | uint8_t last_gc; /* Most out of date gen in the btree */ | |
199 | uint8_t gc_gen; | |
200 | uint16_t gc_mark; | |
201 | }; | |
202 | ||
203 | /* | |
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 | |
206 | */ | |
207 | ||
208 | BITMASK(GC_MARK, struct bucket, gc_mark, 0, 2); | |
209 | #define GC_MARK_RECLAIMABLE 0 | |
210 | #define GC_MARK_DIRTY 1 | |
211 | #define GC_MARK_METADATA 2 | |
212 | BITMASK(GC_SECTORS_USED, struct bucket, gc_mark, 2, 14); | |
213 | ||
214 | struct bkey { | |
215 | uint64_t high; | |
216 | uint64_t low; | |
217 | uint64_t ptr[]; | |
218 | }; | |
219 | ||
220 | /* Enough for a key with 6 pointers */ | |
221 | #define BKEY_PAD 8 | |
222 | ||
223 | #define BKEY_PADDED(key) \ | |
224 | union { struct bkey key; uint64_t key ## _pad[BKEY_PAD]; } | |
225 | ||
226 | /* Version 1: Backing device | |
227 | * Version 2: Seed pointer into btree node checksum | |
228 | * Version 3: New UUID format | |
229 | */ | |
230 | #define BCACHE_SB_VERSION 3 | |
231 | ||
232 | #define SB_SECTOR 8 | |
233 | #define SB_SIZE 4096 | |
234 | #define SB_LABEL_SIZE 32 | |
235 | #define SB_JOURNAL_BUCKETS 256U | |
236 | /* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */ | |
237 | #define MAX_CACHES_PER_SET 8 | |
238 | ||
239 | #define BDEV_DATA_START 16 /* sectors */ | |
240 | ||
241 | struct cache_sb { | |
242 | uint64_t csum; | |
243 | uint64_t offset; /* sector where this sb was written */ | |
244 | uint64_t version; | |
245 | #define CACHE_BACKING_DEV 1 | |
246 | ||
247 | uint8_t magic[16]; | |
248 | ||
249 | uint8_t uuid[16]; | |
250 | union { | |
251 | uint8_t set_uuid[16]; | |
252 | uint64_t set_magic; | |
253 | }; | |
254 | uint8_t label[SB_LABEL_SIZE]; | |
255 | ||
256 | uint64_t flags; | |
257 | uint64_t seq; | |
258 | uint64_t pad[8]; | |
259 | ||
260 | uint64_t nbuckets; /* device size */ | |
261 | uint16_t block_size; /* sectors */ | |
262 | uint16_t bucket_size; /* sectors */ | |
263 | ||
264 | uint16_t nr_in_set; | |
265 | uint16_t nr_this_dev; | |
266 | ||
267 | uint32_t last_mount; /* time_t */ | |
268 | ||
269 | uint16_t first_bucket; | |
270 | union { | |
271 | uint16_t njournal_buckets; | |
272 | uint16_t keys; | |
273 | }; | |
274 | uint64_t d[SB_JOURNAL_BUCKETS]; /* journal buckets */ | |
275 | }; | |
276 | ||
277 | BITMASK(CACHE_SYNC, struct cache_sb, flags, 0, 1); | |
278 | BITMASK(CACHE_DISCARD, struct cache_sb, flags, 1, 1); | |
279 | BITMASK(CACHE_REPLACEMENT, struct cache_sb, flags, 2, 3); | |
280 | #define CACHE_REPLACEMENT_LRU 0U | |
281 | #define CACHE_REPLACEMENT_FIFO 1U | |
282 | #define CACHE_REPLACEMENT_RANDOM 2U | |
283 | ||
284 | BITMASK(BDEV_CACHE_MODE, struct cache_sb, flags, 0, 4); | |
285 | #define CACHE_MODE_WRITETHROUGH 0U | |
286 | #define CACHE_MODE_WRITEBACK 1U | |
287 | #define CACHE_MODE_WRITEAROUND 2U | |
288 | #define CACHE_MODE_NONE 3U | |
289 | BITMASK(BDEV_STATE, struct cache_sb, flags, 61, 2); | |
290 | #define BDEV_STATE_NONE 0U | |
291 | #define BDEV_STATE_CLEAN 1U | |
292 | #define BDEV_STATE_DIRTY 2U | |
293 | #define BDEV_STATE_STALE 3U | |
294 | ||
295 | /* Version 1: Seed pointer into btree node checksum | |
296 | */ | |
297 | #define BCACHE_BSET_VERSION 1 | |
298 | ||
299 | /* | |
300 | * This is the on disk format for btree nodes - a btree node on disk is a list | |
301 | * of these; within each set the keys are sorted | |
302 | */ | |
303 | struct bset { | |
304 | uint64_t csum; | |
305 | uint64_t magic; | |
306 | uint64_t seq; | |
307 | uint32_t version; | |
308 | uint32_t keys; | |
309 | ||
310 | union { | |
311 | struct bkey start[0]; | |
312 | uint64_t d[0]; | |
313 | }; | |
314 | }; | |
315 | ||
316 | /* | |
317 | * On disk format for priorities and gens - see super.c near prio_write() for | |
318 | * more. | |
319 | */ | |
320 | struct prio_set { | |
321 | uint64_t csum; | |
322 | uint64_t magic; | |
323 | uint64_t seq; | |
324 | uint32_t version; | |
325 | uint32_t pad; | |
326 | ||
327 | uint64_t next_bucket; | |
328 | ||
329 | struct bucket_disk { | |
330 | uint16_t prio; | |
331 | uint8_t gen; | |
332 | } __attribute((packed)) data[]; | |
333 | }; | |
334 | ||
335 | struct uuid_entry { | |
336 | union { | |
337 | struct { | |
338 | uint8_t uuid[16]; | |
339 | uint8_t label[32]; | |
340 | uint32_t first_reg; | |
341 | uint32_t last_reg; | |
342 | uint32_t invalidated; | |
343 | ||
344 | uint32_t flags; | |
345 | /* Size of flash only volumes */ | |
346 | uint64_t sectors; | |
347 | }; | |
348 | ||
349 | uint8_t pad[128]; | |
350 | }; | |
351 | }; | |
352 | ||
353 | BITMASK(UUID_FLASH_ONLY, struct uuid_entry, flags, 0, 1); | |
354 | ||
355 | #include "journal.h" | |
356 | #include "stats.h" | |
357 | struct search; | |
358 | struct btree; | |
359 | struct keybuf; | |
360 | ||
361 | struct keybuf_key { | |
362 | struct rb_node node; | |
363 | BKEY_PADDED(key); | |
364 | void *private; | |
365 | }; | |
366 | ||
367 | typedef bool (keybuf_pred_fn)(struct keybuf *, struct bkey *); | |
368 | ||
369 | struct keybuf { | |
370 | keybuf_pred_fn *key_predicate; | |
371 | ||
372 | struct bkey last_scanned; | |
373 | spinlock_t lock; | |
374 | ||
375 | /* | |
376 | * Beginning and end of range in rb tree - so that we can skip taking | |
377 | * lock and checking the rb tree when we need to check for overlapping | |
378 | * keys. | |
379 | */ | |
380 | struct bkey start; | |
381 | struct bkey end; | |
382 | ||
383 | struct rb_root keys; | |
384 | ||
385 | #define KEYBUF_NR 100 | |
386 | DECLARE_ARRAY_ALLOCATOR(struct keybuf_key, freelist, KEYBUF_NR); | |
387 | }; | |
388 | ||
389 | struct bio_split_pool { | |
390 | struct bio_set *bio_split; | |
391 | mempool_t *bio_split_hook; | |
392 | }; | |
393 | ||
394 | struct bio_split_hook { | |
395 | struct closure cl; | |
396 | struct bio_split_pool *p; | |
397 | struct bio *bio; | |
398 | bio_end_io_t *bi_end_io; | |
399 | void *bi_private; | |
400 | }; | |
401 | ||
402 | struct bcache_device { | |
403 | struct closure cl; | |
404 | ||
405 | struct kobject kobj; | |
406 | ||
407 | struct cache_set *c; | |
408 | unsigned id; | |
409 | #define BCACHEDEVNAME_SIZE 12 | |
410 | char name[BCACHEDEVNAME_SIZE]; | |
411 | ||
412 | struct gendisk *disk; | |
413 | ||
414 | /* If nonzero, we're closing */ | |
415 | atomic_t closing; | |
416 | ||
417 | /* If nonzero, we're detaching/unregistering from cache set */ | |
418 | atomic_t detaching; | |
419 | ||
420 | atomic_long_t sectors_dirty; | |
421 | unsigned long sectors_dirty_gc; | |
422 | unsigned long sectors_dirty_last; | |
423 | long sectors_dirty_derivative; | |
424 | ||
425 | mempool_t *unaligned_bvec; | |
426 | struct bio_set *bio_split; | |
427 | ||
428 | unsigned data_csum:1; | |
429 | ||
430 | int (*cache_miss)(struct btree *, struct search *, | |
431 | struct bio *, unsigned); | |
432 | int (*ioctl) (struct bcache_device *, fmode_t, unsigned, unsigned long); | |
433 | ||
434 | struct bio_split_pool bio_split_hook; | |
435 | }; | |
436 | ||
437 | struct io { | |
438 | /* Used to track sequential IO so it can be skipped */ | |
439 | struct hlist_node hash; | |
440 | struct list_head lru; | |
441 | ||
442 | unsigned long jiffies; | |
443 | unsigned sequential; | |
444 | sector_t last; | |
445 | }; | |
446 | ||
447 | struct cached_dev { | |
448 | struct list_head list; | |
449 | struct bcache_device disk; | |
450 | struct block_device *bdev; | |
451 | ||
452 | struct cache_sb sb; | |
453 | struct bio sb_bio; | |
454 | struct bio_vec sb_bv[1]; | |
455 | struct closure_with_waitlist sb_write; | |
456 | ||
457 | /* Refcount on the cache set. Always nonzero when we're caching. */ | |
458 | atomic_t count; | |
459 | struct work_struct detach; | |
460 | ||
461 | /* | |
462 | * Device might not be running if it's dirty and the cache set hasn't | |
463 | * showed up yet. | |
464 | */ | |
465 | atomic_t running; | |
466 | ||
467 | /* | |
468 | * Writes take a shared lock from start to finish; scanning for dirty | |
469 | * data to refill the rb tree requires an exclusive lock. | |
470 | */ | |
471 | struct rw_semaphore writeback_lock; | |
472 | ||
473 | /* | |
474 | * Nonzero, and writeback has a refcount (d->count), iff there is dirty | |
475 | * data in the cache. Protected by writeback_lock; must have an | |
476 | * shared lock to set and exclusive lock to clear. | |
477 | */ | |
478 | atomic_t has_dirty; | |
479 | ||
480 | struct ratelimit writeback_rate; | |
481 | struct delayed_work writeback_rate_update; | |
482 | ||
483 | /* | |
484 | * Internal to the writeback code, so read_dirty() can keep track of | |
485 | * where it's at. | |
486 | */ | |
487 | sector_t last_read; | |
488 | ||
489 | /* Number of writeback bios in flight */ | |
490 | atomic_t in_flight; | |
491 | struct closure_with_timer writeback; | |
492 | struct closure_waitlist writeback_wait; | |
493 | ||
494 | struct keybuf writeback_keys; | |
495 | ||
496 | /* For tracking sequential IO */ | |
497 | #define RECENT_IO_BITS 7 | |
498 | #define RECENT_IO (1 << RECENT_IO_BITS) | |
499 | struct io io[RECENT_IO]; | |
500 | struct hlist_head io_hash[RECENT_IO + 1]; | |
501 | struct list_head io_lru; | |
502 | spinlock_t io_lock; | |
503 | ||
504 | struct cache_accounting accounting; | |
505 | ||
506 | /* The rest of this all shows up in sysfs */ | |
507 | unsigned sequential_cutoff; | |
508 | unsigned readahead; | |
509 | ||
510 | unsigned sequential_merge:1; | |
511 | unsigned verify:1; | |
512 | ||
513 | unsigned writeback_metadata:1; | |
514 | unsigned writeback_running:1; | |
515 | unsigned char writeback_percent; | |
516 | unsigned writeback_delay; | |
517 | ||
518 | int writeback_rate_change; | |
519 | int64_t writeback_rate_derivative; | |
520 | uint64_t writeback_rate_target; | |
521 | ||
522 | unsigned writeback_rate_update_seconds; | |
523 | unsigned writeback_rate_d_term; | |
524 | unsigned writeback_rate_p_term_inverse; | |
525 | unsigned writeback_rate_d_smooth; | |
526 | }; | |
527 | ||
528 | enum alloc_watermarks { | |
529 | WATERMARK_PRIO, | |
530 | WATERMARK_METADATA, | |
531 | WATERMARK_MOVINGGC, | |
532 | WATERMARK_NONE, | |
533 | WATERMARK_MAX | |
534 | }; | |
535 | ||
536 | struct cache { | |
537 | struct cache_set *set; | |
538 | struct cache_sb sb; | |
539 | struct bio sb_bio; | |
540 | struct bio_vec sb_bv[1]; | |
541 | ||
542 | struct kobject kobj; | |
543 | struct block_device *bdev; | |
544 | ||
545 | unsigned watermark[WATERMARK_MAX]; | |
546 | ||
547 | struct closure alloc; | |
548 | struct workqueue_struct *alloc_workqueue; | |
549 | ||
550 | struct closure prio; | |
551 | struct prio_set *disk_buckets; | |
552 | ||
553 | /* | |
554 | * When allocating new buckets, prio_write() gets first dibs - since we | |
555 | * may not be allocate at all without writing priorities and gens. | |
556 | * prio_buckets[] contains the last buckets we wrote priorities to (so | |
557 | * gc can mark them as metadata), prio_next[] contains the buckets | |
558 | * allocated for the next prio write. | |
559 | */ | |
560 | uint64_t *prio_buckets; | |
561 | uint64_t *prio_last_buckets; | |
562 | ||
563 | /* | |
564 | * free: Buckets that are ready to be used | |
565 | * | |
566 | * free_inc: Incoming buckets - these are buckets that currently have | |
567 | * cached data in them, and we can't reuse them until after we write | |
568 | * their new gen to disk. After prio_write() finishes writing the new | |
569 | * gens/prios, they'll be moved to the free list (and possibly discarded | |
570 | * in the process) | |
571 | * | |
572 | * unused: GC found nothing pointing into these buckets (possibly | |
573 | * because all the data they contained was overwritten), so we only | |
574 | * need to discard them before they can be moved to the free list. | |
575 | */ | |
576 | DECLARE_FIFO(long, free); | |
577 | DECLARE_FIFO(long, free_inc); | |
578 | DECLARE_FIFO(long, unused); | |
579 | ||
580 | size_t fifo_last_bucket; | |
581 | ||
582 | /* Allocation stuff: */ | |
583 | struct bucket *buckets; | |
584 | ||
585 | DECLARE_HEAP(struct bucket *, heap); | |
586 | ||
587 | /* | |
588 | * max(gen - disk_gen) for all buckets. When it gets too big we have to | |
589 | * call prio_write() to keep gens from wrapping. | |
590 | */ | |
591 | uint8_t need_save_prio; | |
592 | unsigned gc_move_threshold; | |
593 | ||
594 | /* | |
595 | * If nonzero, we know we aren't going to find any buckets to invalidate | |
596 | * until a gc finishes - otherwise we could pointlessly burn a ton of | |
597 | * cpu | |
598 | */ | |
599 | unsigned invalidate_needs_gc:1; | |
600 | ||
601 | bool discard; /* Get rid of? */ | |
602 | ||
603 | /* | |
604 | * We preallocate structs for issuing discards to buckets, and keep them | |
605 | * on this list when they're not in use; do_discard() issues discards | |
606 | * whenever there's work to do and is called by free_some_buckets() and | |
607 | * when a discard finishes. | |
608 | */ | |
609 | atomic_t discards_in_flight; | |
610 | struct list_head discards; | |
611 | ||
612 | struct journal_device journal; | |
613 | ||
614 | /* The rest of this all shows up in sysfs */ | |
615 | #define IO_ERROR_SHIFT 20 | |
616 | atomic_t io_errors; | |
617 | atomic_t io_count; | |
618 | ||
619 | atomic_long_t meta_sectors_written; | |
620 | atomic_long_t btree_sectors_written; | |
621 | atomic_long_t sectors_written; | |
622 | ||
623 | struct bio_split_pool bio_split_hook; | |
624 | }; | |
625 | ||
626 | struct gc_stat { | |
627 | size_t nodes; | |
628 | size_t key_bytes; | |
629 | ||
630 | size_t nkeys; | |
631 | uint64_t data; /* sectors */ | |
632 | uint64_t dirty; /* sectors */ | |
633 | unsigned in_use; /* percent */ | |
634 | }; | |
635 | ||
636 | /* | |
637 | * Flag bits, for how the cache set is shutting down, and what phase it's at: | |
638 | * | |
639 | * CACHE_SET_UNREGISTERING means we're not just shutting down, we're detaching | |
640 | * all the backing devices first (their cached data gets invalidated, and they | |
641 | * won't automatically reattach). | |
642 | * | |
643 | * CACHE_SET_STOPPING always gets set first when we're closing down a cache set; | |
644 | * we'll continue to run normally for awhile with CACHE_SET_STOPPING set (i.e. | |
645 | * flushing dirty data). | |
646 | * | |
647 | * CACHE_SET_STOPPING_2 gets set at the last phase, when it's time to shut down the | |
648 | * allocation thread. | |
649 | */ | |
650 | #define CACHE_SET_UNREGISTERING 0 | |
651 | #define CACHE_SET_STOPPING 1 | |
652 | #define CACHE_SET_STOPPING_2 2 | |
653 | ||
654 | struct cache_set { | |
655 | struct closure cl; | |
656 | ||
657 | struct list_head list; | |
658 | struct kobject kobj; | |
659 | struct kobject internal; | |
660 | struct dentry *debug; | |
661 | struct cache_accounting accounting; | |
662 | ||
663 | unsigned long flags; | |
664 | ||
665 | struct cache_sb sb; | |
666 | ||
667 | struct cache *cache[MAX_CACHES_PER_SET]; | |
668 | struct cache *cache_by_alloc[MAX_CACHES_PER_SET]; | |
669 | int caches_loaded; | |
670 | ||
671 | struct bcache_device **devices; | |
672 | struct list_head cached_devs; | |
673 | uint64_t cached_dev_sectors; | |
674 | struct closure caching; | |
675 | ||
676 | struct closure_with_waitlist sb_write; | |
677 | ||
678 | mempool_t *search; | |
679 | mempool_t *bio_meta; | |
680 | struct bio_set *bio_split; | |
681 | ||
682 | /* For the btree cache */ | |
683 | struct shrinker shrink; | |
684 | ||
685 | /* For the allocator itself */ | |
686 | wait_queue_head_t alloc_wait; | |
687 | ||
688 | /* For the btree cache and anything allocation related */ | |
689 | struct mutex bucket_lock; | |
690 | ||
691 | /* log2(bucket_size), in sectors */ | |
692 | unsigned short bucket_bits; | |
693 | ||
694 | /* log2(block_size), in sectors */ | |
695 | unsigned short block_bits; | |
696 | ||
697 | /* | |
698 | * Default number of pages for a new btree node - may be less than a | |
699 | * full bucket | |
700 | */ | |
701 | unsigned btree_pages; | |
702 | ||
703 | /* | |
704 | * Lists of struct btrees; lru is the list for structs that have memory | |
705 | * allocated for actual btree node, freed is for structs that do not. | |
706 | * | |
707 | * We never free a struct btree, except on shutdown - we just put it on | |
708 | * the btree_cache_freed list and reuse it later. This simplifies the | |
709 | * code, and it doesn't cost us much memory as the memory usage is | |
710 | * dominated by buffers that hold the actual btree node data and those | |
711 | * can be freed - and the number of struct btrees allocated is | |
712 | * effectively bounded. | |
713 | * | |
714 | * btree_cache_freeable effectively is a small cache - we use it because | |
715 | * high order page allocations can be rather expensive, and it's quite | |
716 | * common to delete and allocate btree nodes in quick succession. It | |
717 | * should never grow past ~2-3 nodes in practice. | |
718 | */ | |
719 | struct list_head btree_cache; | |
720 | struct list_head btree_cache_freeable; | |
721 | struct list_head btree_cache_freed; | |
722 | ||
723 | /* Number of elements in btree_cache + btree_cache_freeable lists */ | |
724 | unsigned bucket_cache_used; | |
725 | ||
726 | /* | |
727 | * If we need to allocate memory for a new btree node and that | |
728 | * allocation fails, we can cannibalize another node in the btree cache | |
729 | * to satisfy the allocation. However, only one thread can be doing this | |
730 | * at a time, for obvious reasons - try_harder and try_wait are | |
731 | * basically a lock for this that we can wait on asynchronously. The | |
732 | * btree_root() macro releases the lock when it returns. | |
733 | */ | |
734 | struct closure *try_harder; | |
735 | struct closure_waitlist try_wait; | |
736 | uint64_t try_harder_start; | |
737 | ||
738 | /* | |
739 | * When we free a btree node, we increment the gen of the bucket the | |
740 | * node is in - but we can't rewrite the prios and gens until we | |
741 | * finished whatever it is we were doing, otherwise after a crash the | |
742 | * btree node would be freed but for say a split, we might not have the | |
743 | * pointers to the new nodes inserted into the btree yet. | |
744 | * | |
745 | * This is a refcount that blocks prio_write() until the new keys are | |
746 | * written. | |
747 | */ | |
748 | atomic_t prio_blocked; | |
749 | struct closure_waitlist bucket_wait; | |
750 | ||
751 | /* | |
752 | * For any bio we don't skip we subtract the number of sectors from | |
753 | * rescale; when it hits 0 we rescale all the bucket priorities. | |
754 | */ | |
755 | atomic_t rescale; | |
756 | /* | |
757 | * When we invalidate buckets, we use both the priority and the amount | |
758 | * of good data to determine which buckets to reuse first - to weight | |
759 | * those together consistently we keep track of the smallest nonzero | |
760 | * priority of any bucket. | |
761 | */ | |
762 | uint16_t min_prio; | |
763 | ||
764 | /* | |
765 | * max(gen - gc_gen) for all buckets. When it gets too big we have to gc | |
766 | * to keep gens from wrapping around. | |
767 | */ | |
768 | uint8_t need_gc; | |
769 | struct gc_stat gc_stats; | |
770 | size_t nbuckets; | |
771 | ||
772 | struct closure_with_waitlist gc; | |
773 | /* Where in the btree gc currently is */ | |
774 | struct bkey gc_done; | |
775 | ||
776 | /* | |
777 | * The allocation code needs gc_mark in struct bucket to be correct, but | |
778 | * it's not while a gc is in progress. Protected by bucket_lock. | |
779 | */ | |
780 | int gc_mark_valid; | |
781 | ||
782 | /* Counts how many sectors bio_insert has added to the cache */ | |
783 | atomic_t sectors_to_gc; | |
784 | ||
785 | struct closure moving_gc; | |
786 | struct closure_waitlist moving_gc_wait; | |
787 | struct keybuf moving_gc_keys; | |
788 | /* Number of moving GC bios in flight */ | |
789 | atomic_t in_flight; | |
790 | ||
791 | struct btree *root; | |
792 | ||
793 | #ifdef CONFIG_BCACHE_DEBUG | |
794 | struct btree *verify_data; | |
795 | struct mutex verify_lock; | |
796 | #endif | |
797 | ||
798 | unsigned nr_uuids; | |
799 | struct uuid_entry *uuids; | |
800 | BKEY_PADDED(uuid_bucket); | |
801 | struct closure_with_waitlist uuid_write; | |
802 | ||
803 | /* | |
804 | * A btree node on disk could have too many bsets for an iterator to fit | |
805 | * on the stack - this is a single element mempool for btree_read_work() | |
806 | */ | |
807 | struct mutex fill_lock; | |
808 | struct btree_iter *fill_iter; | |
809 | ||
810 | /* | |
811 | * btree_sort() is a merge sort and requires temporary space - single | |
812 | * element mempool | |
813 | */ | |
814 | struct mutex sort_lock; | |
815 | struct bset *sort; | |
816 | ||
817 | /* List of buckets we're currently writing data to */ | |
818 | struct list_head data_buckets; | |
819 | spinlock_t data_bucket_lock; | |
820 | ||
821 | struct journal journal; | |
822 | ||
823 | #define CONGESTED_MAX 1024 | |
824 | unsigned congested_last_us; | |
825 | atomic_t congested; | |
826 | ||
827 | /* The rest of this all shows up in sysfs */ | |
828 | unsigned congested_read_threshold_us; | |
829 | unsigned congested_write_threshold_us; | |
830 | ||
831 | spinlock_t sort_time_lock; | |
832 | struct time_stats sort_time; | |
833 | struct time_stats btree_gc_time; | |
834 | struct time_stats btree_split_time; | |
835 | spinlock_t btree_read_time_lock; | |
836 | struct time_stats btree_read_time; | |
837 | struct time_stats try_harder_time; | |
838 | ||
839 | atomic_long_t cache_read_races; | |
840 | atomic_long_t writeback_keys_done; | |
841 | atomic_long_t writeback_keys_failed; | |
842 | unsigned error_limit; | |
843 | unsigned error_decay; | |
844 | unsigned short journal_delay_ms; | |
845 | unsigned verify:1; | |
846 | unsigned key_merging_disabled:1; | |
847 | unsigned gc_always_rewrite:1; | |
848 | unsigned shrinker_disabled:1; | |
849 | unsigned copy_gc_enabled:1; | |
850 | ||
851 | #define BUCKET_HASH_BITS 12 | |
852 | struct hlist_head bucket_hash[1 << BUCKET_HASH_BITS]; | |
853 | }; | |
854 | ||
855 | static inline bool key_merging_disabled(struct cache_set *c) | |
856 | { | |
857 | #ifdef CONFIG_BCACHE_DEBUG | |
858 | return c->key_merging_disabled; | |
859 | #else | |
860 | return 0; | |
861 | #endif | |
862 | } | |
863 | ||
864 | struct bbio { | |
865 | unsigned submit_time_us; | |
866 | union { | |
867 | struct bkey key; | |
868 | uint64_t _pad[3]; | |
869 | /* | |
870 | * We only need pad = 3 here because we only ever carry around a | |
871 | * single pointer - i.e. the pointer we're doing io to/from. | |
872 | */ | |
873 | }; | |
874 | struct bio bio; | |
875 | }; | |
876 | ||
877 | static inline unsigned local_clock_us(void) | |
878 | { | |
879 | return local_clock() >> 10; | |
880 | } | |
881 | ||
882 | #define MAX_BSETS 4U | |
883 | ||
884 | #define BTREE_PRIO USHRT_MAX | |
885 | #define INITIAL_PRIO 32768 | |
886 | ||
887 | #define btree_bytes(c) ((c)->btree_pages * PAGE_SIZE) | |
888 | #define btree_blocks(b) \ | |
889 | ((unsigned) (KEY_SIZE(&b->key) >> (b)->c->block_bits)) | |
890 | ||
891 | #define btree_default_blocks(c) \ | |
892 | ((unsigned) ((PAGE_SECTORS * (c)->btree_pages) >> (c)->block_bits)) | |
893 | ||
894 | #define bucket_pages(c) ((c)->sb.bucket_size / PAGE_SECTORS) | |
895 | #define bucket_bytes(c) ((c)->sb.bucket_size << 9) | |
896 | #define block_bytes(c) ((c)->sb.block_size << 9) | |
897 | ||
898 | #define __set_bytes(i, k) (sizeof(*(i)) + (k) * sizeof(uint64_t)) | |
899 | #define set_bytes(i) __set_bytes(i, i->keys) | |
900 | ||
901 | #define __set_blocks(i, k, c) DIV_ROUND_UP(__set_bytes(i, k), block_bytes(c)) | |
902 | #define set_blocks(i, c) __set_blocks(i, (i)->keys, c) | |
903 | ||
904 | #define node(i, j) ((struct bkey *) ((i)->d + (j))) | |
905 | #define end(i) node(i, (i)->keys) | |
906 | ||
907 | #define index(i, b) \ | |
908 | ((size_t) (((void *) i - (void *) (b)->sets[0].data) / \ | |
909 | block_bytes(b->c))) | |
910 | ||
911 | #define btree_data_space(b) (PAGE_SIZE << (b)->page_order) | |
912 | ||
913 | #define prios_per_bucket(c) \ | |
914 | ((bucket_bytes(c) - sizeof(struct prio_set)) / \ | |
915 | sizeof(struct bucket_disk)) | |
916 | #define prio_buckets(c) \ | |
917 | DIV_ROUND_UP((size_t) (c)->sb.nbuckets, prios_per_bucket(c)) | |
918 | ||
919 | #define JSET_MAGIC 0x245235c1a3625032ULL | |
920 | #define PSET_MAGIC 0x6750e15f87337f91ULL | |
921 | #define BSET_MAGIC 0x90135c78b99e07f5ULL | |
922 | ||
923 | #define jset_magic(c) ((c)->sb.set_magic ^ JSET_MAGIC) | |
924 | #define pset_magic(c) ((c)->sb.set_magic ^ PSET_MAGIC) | |
925 | #define bset_magic(c) ((c)->sb.set_magic ^ BSET_MAGIC) | |
926 | ||
927 | /* Bkey fields: all units are in sectors */ | |
928 | ||
929 | #define KEY_FIELD(name, field, offset, size) \ | |
930 | BITMASK(name, struct bkey, field, offset, size) | |
931 | ||
932 | #define PTR_FIELD(name, offset, size) \ | |
933 | static inline uint64_t name(const struct bkey *k, unsigned i) \ | |
934 | { return (k->ptr[i] >> offset) & ~(((uint64_t) ~0) << size); } \ | |
935 | \ | |
936 | static inline void SET_##name(struct bkey *k, unsigned i, uint64_t v)\ | |
937 | { \ | |
938 | k->ptr[i] &= ~(~((uint64_t) ~0 << size) << offset); \ | |
939 | k->ptr[i] |= v << offset; \ | |
940 | } | |
941 | ||
942 | KEY_FIELD(KEY_PTRS, high, 60, 3) | |
943 | KEY_FIELD(HEADER_SIZE, high, 58, 2) | |
944 | KEY_FIELD(KEY_CSUM, high, 56, 2) | |
945 | KEY_FIELD(KEY_PINNED, high, 55, 1) | |
946 | KEY_FIELD(KEY_DIRTY, high, 36, 1) | |
947 | ||
948 | KEY_FIELD(KEY_SIZE, high, 20, 16) | |
949 | KEY_FIELD(KEY_INODE, high, 0, 20) | |
950 | ||
951 | /* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */ | |
952 | ||
953 | static inline uint64_t KEY_OFFSET(const struct bkey *k) | |
954 | { | |
955 | return k->low; | |
956 | } | |
957 | ||
958 | static inline void SET_KEY_OFFSET(struct bkey *k, uint64_t v) | |
959 | { | |
960 | k->low = v; | |
961 | } | |
962 | ||
963 | PTR_FIELD(PTR_DEV, 51, 12) | |
964 | PTR_FIELD(PTR_OFFSET, 8, 43) | |
965 | PTR_FIELD(PTR_GEN, 0, 8) | |
966 | ||
967 | #define PTR_CHECK_DEV ((1 << 12) - 1) | |
968 | ||
969 | #define PTR(gen, offset, dev) \ | |
970 | ((((uint64_t) dev) << 51) | ((uint64_t) offset) << 8 | gen) | |
971 | ||
972 | static inline size_t sector_to_bucket(struct cache_set *c, sector_t s) | |
973 | { | |
974 | return s >> c->bucket_bits; | |
975 | } | |
976 | ||
977 | static inline sector_t bucket_to_sector(struct cache_set *c, size_t b) | |
978 | { | |
979 | return ((sector_t) b) << c->bucket_bits; | |
980 | } | |
981 | ||
982 | static inline sector_t bucket_remainder(struct cache_set *c, sector_t s) | |
983 | { | |
984 | return s & (c->sb.bucket_size - 1); | |
985 | } | |
986 | ||
987 | static inline struct cache *PTR_CACHE(struct cache_set *c, | |
988 | const struct bkey *k, | |
989 | unsigned ptr) | |
990 | { | |
991 | return c->cache[PTR_DEV(k, ptr)]; | |
992 | } | |
993 | ||
994 | static inline size_t PTR_BUCKET_NR(struct cache_set *c, | |
995 | const struct bkey *k, | |
996 | unsigned ptr) | |
997 | { | |
998 | return sector_to_bucket(c, PTR_OFFSET(k, ptr)); | |
999 | } | |
1000 | ||
1001 | static inline struct bucket *PTR_BUCKET(struct cache_set *c, | |
1002 | const struct bkey *k, | |
1003 | unsigned ptr) | |
1004 | { | |
1005 | return PTR_CACHE(c, k, ptr)->buckets + PTR_BUCKET_NR(c, k, ptr); | |
1006 | } | |
1007 | ||
1008 | /* Btree key macros */ | |
1009 | ||
1010 | /* | |
1011 | * The high bit being set is a relic from when we used it to do binary | |
1012 | * searches - it told you where a key started. It's not used anymore, | |
1013 | * and can probably be safely dropped. | |
1014 | */ | |
1015 | #define KEY(dev, sector, len) (struct bkey) \ | |
1016 | { \ | |
1017 | .high = (1ULL << 63) | ((uint64_t) (len) << 20) | (dev), \ | |
1018 | .low = (sector) \ | |
1019 | } | |
1020 | ||
1021 | static inline void bkey_init(struct bkey *k) | |
1022 | { | |
1023 | *k = KEY(0, 0, 0); | |
1024 | } | |
1025 | ||
1026 | #define KEY_START(k) (KEY_OFFSET(k) - KEY_SIZE(k)) | |
1027 | #define START_KEY(k) KEY(KEY_INODE(k), KEY_START(k), 0) | |
1028 | #define MAX_KEY KEY(~(~0 << 20), ((uint64_t) ~0) >> 1, 0) | |
1029 | #define ZERO_KEY KEY(0, 0, 0) | |
1030 | ||
1031 | /* | |
1032 | * This is used for various on disk data structures - cache_sb, prio_set, bset, | |
1033 | * jset: The checksum is _always_ the first 8 bytes of these structs | |
1034 | */ | |
1035 | #define csum_set(i) \ | |
1036 | crc64(((void *) (i)) + sizeof(uint64_t), \ | |
1037 | ((void *) end(i)) - (((void *) (i)) + sizeof(uint64_t))) | |
1038 | ||
1039 | /* Error handling macros */ | |
1040 | ||
1041 | #define btree_bug(b, ...) \ | |
1042 | do { \ | |
1043 | if (bch_cache_set_error((b)->c, __VA_ARGS__)) \ | |
1044 | dump_stack(); \ | |
1045 | } while (0) | |
1046 | ||
1047 | #define cache_bug(c, ...) \ | |
1048 | do { \ | |
1049 | if (bch_cache_set_error(c, __VA_ARGS__)) \ | |
1050 | dump_stack(); \ | |
1051 | } while (0) | |
1052 | ||
1053 | #define btree_bug_on(cond, b, ...) \ | |
1054 | do { \ | |
1055 | if (cond) \ | |
1056 | btree_bug(b, __VA_ARGS__); \ | |
1057 | } while (0) | |
1058 | ||
1059 | #define cache_bug_on(cond, c, ...) \ | |
1060 | do { \ | |
1061 | if (cond) \ | |
1062 | cache_bug(c, __VA_ARGS__); \ | |
1063 | } while (0) | |
1064 | ||
1065 | #define cache_set_err_on(cond, c, ...) \ | |
1066 | do { \ | |
1067 | if (cond) \ | |
1068 | bch_cache_set_error(c, __VA_ARGS__); \ | |
1069 | } while (0) | |
1070 | ||
1071 | /* Looping macros */ | |
1072 | ||
1073 | #define for_each_cache(ca, cs, iter) \ | |
1074 | for (iter = 0; ca = cs->cache[iter], iter < (cs)->sb.nr_in_set; iter++) | |
1075 | ||
1076 | #define for_each_bucket(b, ca) \ | |
1077 | for (b = (ca)->buckets + (ca)->sb.first_bucket; \ | |
1078 | b < (ca)->buckets + (ca)->sb.nbuckets; b++) | |
1079 | ||
1080 | static inline void __bkey_put(struct cache_set *c, struct bkey *k) | |
1081 | { | |
1082 | unsigned i; | |
1083 | ||
1084 | for (i = 0; i < KEY_PTRS(k); i++) | |
1085 | atomic_dec_bug(&PTR_BUCKET(c, k, i)->pin); | |
1086 | } | |
1087 | ||
1088 | /* Blktrace macros */ | |
1089 | ||
1090 | #define blktrace_msg(c, fmt, ...) \ | |
1091 | do { \ | |
1092 | struct request_queue *q = bdev_get_queue(c->bdev); \ | |
1093 | if (q) \ | |
1094 | blk_add_trace_msg(q, fmt, ##__VA_ARGS__); \ | |
1095 | } while (0) | |
1096 | ||
1097 | #define blktrace_msg_all(s, fmt, ...) \ | |
1098 | do { \ | |
1099 | struct cache *_c; \ | |
1100 | unsigned i; \ | |
1101 | for_each_cache(_c, (s), i) \ | |
1102 | blktrace_msg(_c, fmt, ##__VA_ARGS__); \ | |
1103 | } while (0) | |
1104 | ||
1105 | static inline void cached_dev_put(struct cached_dev *dc) | |
1106 | { | |
1107 | if (atomic_dec_and_test(&dc->count)) | |
1108 | schedule_work(&dc->detach); | |
1109 | } | |
1110 | ||
1111 | static inline bool cached_dev_get(struct cached_dev *dc) | |
1112 | { | |
1113 | if (!atomic_inc_not_zero(&dc->count)) | |
1114 | return false; | |
1115 | ||
1116 | /* Paired with the mb in cached_dev_attach */ | |
1117 | smp_mb__after_atomic_inc(); | |
1118 | return true; | |
1119 | } | |
1120 | ||
1121 | /* | |
1122 | * bucket_gc_gen() returns the difference between the bucket's current gen and | |
1123 | * the oldest gen of any pointer into that bucket in the btree (last_gc). | |
1124 | * | |
1125 | * bucket_disk_gen() returns the difference between the current gen and the gen | |
1126 | * on disk; they're both used to make sure gens don't wrap around. | |
1127 | */ | |
1128 | ||
1129 | static inline uint8_t bucket_gc_gen(struct bucket *b) | |
1130 | { | |
1131 | return b->gen - b->last_gc; | |
1132 | } | |
1133 | ||
1134 | static inline uint8_t bucket_disk_gen(struct bucket *b) | |
1135 | { | |
1136 | return b->gen - b->disk_gen; | |
1137 | } | |
1138 | ||
1139 | #define BUCKET_GC_GEN_MAX 96U | |
1140 | #define BUCKET_DISK_GEN_MAX 64U | |
1141 | ||
1142 | #define kobj_attribute_write(n, fn) \ | |
1143 | static struct kobj_attribute ksysfs_##n = __ATTR(n, S_IWUSR, NULL, fn) | |
1144 | ||
1145 | #define kobj_attribute_rw(n, show, store) \ | |
1146 | static struct kobj_attribute ksysfs_##n = \ | |
1147 | __ATTR(n, S_IWUSR|S_IRUSR, show, store) | |
1148 | ||
1149 | /* Forward declarations */ | |
1150 | ||
1151 | void bch_writeback_queue(struct cached_dev *); | |
1152 | void bch_writeback_add(struct cached_dev *, unsigned); | |
1153 | ||
1154 | void bch_count_io_errors(struct cache *, int, const char *); | |
1155 | void bch_bbio_count_io_errors(struct cache_set *, struct bio *, | |
1156 | int, const char *); | |
1157 | void bch_bbio_endio(struct cache_set *, struct bio *, int, const char *); | |
1158 | void bch_bbio_free(struct bio *, struct cache_set *); | |
1159 | struct bio *bch_bbio_alloc(struct cache_set *); | |
1160 | ||
1161 | struct bio *bch_bio_split(struct bio *, int, gfp_t, struct bio_set *); | |
1162 | void bch_generic_make_request(struct bio *, struct bio_split_pool *); | |
1163 | void __bch_submit_bbio(struct bio *, struct cache_set *); | |
1164 | void bch_submit_bbio(struct bio *, struct cache_set *, struct bkey *, unsigned); | |
1165 | ||
1166 | uint8_t bch_inc_gen(struct cache *, struct bucket *); | |
1167 | void bch_rescale_priorities(struct cache_set *, int); | |
1168 | bool bch_bucket_add_unused(struct cache *, struct bucket *); | |
1169 | void bch_allocator_thread(struct closure *); | |
1170 | ||
1171 | long bch_bucket_alloc(struct cache *, unsigned, struct closure *); | |
1172 | void bch_bucket_free(struct cache_set *, struct bkey *); | |
1173 | ||
1174 | int __bch_bucket_alloc_set(struct cache_set *, unsigned, | |
1175 | struct bkey *, int, struct closure *); | |
1176 | int bch_bucket_alloc_set(struct cache_set *, unsigned, | |
1177 | struct bkey *, int, struct closure *); | |
1178 | ||
1179 | __printf(2, 3) | |
1180 | bool bch_cache_set_error(struct cache_set *, const char *, ...); | |
1181 | ||
1182 | void bch_prio_write(struct cache *); | |
1183 | void bch_write_bdev_super(struct cached_dev *, struct closure *); | |
1184 | ||
1185 | extern struct workqueue_struct *bcache_wq, *bch_gc_wq; | |
1186 | extern const char * const bch_cache_modes[]; | |
1187 | extern struct mutex bch_register_lock; | |
1188 | extern struct list_head bch_cache_sets; | |
1189 | ||
1190 | extern struct kobj_type bch_cached_dev_ktype; | |
1191 | extern struct kobj_type bch_flash_dev_ktype; | |
1192 | extern struct kobj_type bch_cache_set_ktype; | |
1193 | extern struct kobj_type bch_cache_set_internal_ktype; | |
1194 | extern struct kobj_type bch_cache_ktype; | |
1195 | ||
1196 | void bch_cached_dev_release(struct kobject *); | |
1197 | void bch_flash_dev_release(struct kobject *); | |
1198 | void bch_cache_set_release(struct kobject *); | |
1199 | void bch_cache_release(struct kobject *); | |
1200 | ||
1201 | int bch_uuid_write(struct cache_set *); | |
1202 | void bcache_write_super(struct cache_set *); | |
1203 | ||
1204 | int bch_flash_dev_create(struct cache_set *c, uint64_t size); | |
1205 | ||
1206 | int bch_cached_dev_attach(struct cached_dev *, struct cache_set *); | |
1207 | void bch_cached_dev_detach(struct cached_dev *); | |
1208 | void bch_cached_dev_run(struct cached_dev *); | |
1209 | void bcache_device_stop(struct bcache_device *); | |
1210 | ||
1211 | void bch_cache_set_unregister(struct cache_set *); | |
1212 | void bch_cache_set_stop(struct cache_set *); | |
1213 | ||
1214 | struct cache_set *bch_cache_set_alloc(struct cache_sb *); | |
1215 | void bch_btree_cache_free(struct cache_set *); | |
1216 | int bch_btree_cache_alloc(struct cache_set *); | |
1217 | void bch_writeback_init_cached_dev(struct cached_dev *); | |
1218 | void bch_moving_init_cache_set(struct cache_set *); | |
1219 | ||
1220 | void bch_cache_allocator_exit(struct cache *ca); | |
1221 | int bch_cache_allocator_init(struct cache *ca); | |
1222 | ||
1223 | void bch_debug_exit(void); | |
1224 | int bch_debug_init(struct kobject *); | |
1225 | void bch_writeback_exit(void); | |
1226 | int bch_writeback_init(void); | |
1227 | void bch_request_exit(void); | |
1228 | int bch_request_init(void); | |
1229 | void bch_btree_exit(void); | |
1230 | int bch_btree_init(void); | |
1231 | ||
1232 | #endif /* _BCACHE_H */ |