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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2003 Sistina Software Limited. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
7 | #include "dm.h" | |
8 | #include "dm-bio-list.h" | |
9 | #include "dm-io.h" | |
10 | #include "dm-log.h" | |
11 | #include "kcopyd.h" | |
12 | ||
13 | #include <linux/ctype.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/mempool.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/pagemap.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/time.h> | |
20 | #include <linux/vmalloc.h> | |
21 | #include <linux/workqueue.h> | |
22 | ||
23 | static struct workqueue_struct *_kmirrord_wq; | |
24 | static struct work_struct _kmirrord_work; | |
25 | ||
26 | static inline void wake(void) | |
27 | { | |
28 | queue_work(_kmirrord_wq, &_kmirrord_work); | |
29 | } | |
30 | ||
31 | /*----------------------------------------------------------------- | |
32 | * Region hash | |
33 | * | |
34 | * The mirror splits itself up into discrete regions. Each | |
35 | * region can be in one of three states: clean, dirty, | |
36 | * nosync. There is no need to put clean regions in the hash. | |
37 | * | |
38 | * In addition to being present in the hash table a region _may_ | |
39 | * be present on one of three lists. | |
40 | * | |
41 | * clean_regions: Regions on this list have no io pending to | |
42 | * them, they are in sync, we are no longer interested in them, | |
43 | * they are dull. rh_update_states() will remove them from the | |
44 | * hash table. | |
45 | * | |
46 | * quiesced_regions: These regions have been spun down, ready | |
47 | * for recovery. rh_recovery_start() will remove regions from | |
48 | * this list and hand them to kmirrord, which will schedule the | |
49 | * recovery io with kcopyd. | |
50 | * | |
51 | * recovered_regions: Regions that kcopyd has successfully | |
52 | * recovered. rh_update_states() will now schedule any delayed | |
53 | * io, up the recovery_count, and remove the region from the | |
54 | * hash. | |
55 | * | |
56 | * There are 2 locks: | |
57 | * A rw spin lock 'hash_lock' protects just the hash table, | |
58 | * this is never held in write mode from interrupt context, | |
59 | * which I believe means that we only have to disable irqs when | |
60 | * doing a write lock. | |
61 | * | |
62 | * An ordinary spin lock 'region_lock' that protects the three | |
63 | * lists in the region_hash, with the 'state', 'list' and | |
64 | * 'bhs_delayed' fields of the regions. This is used from irq | |
65 | * context, so all other uses will have to suspend local irqs. | |
66 | *---------------------------------------------------------------*/ | |
67 | struct mirror_set; | |
68 | struct region_hash { | |
69 | struct mirror_set *ms; | |
70 | uint32_t region_size; | |
71 | unsigned region_shift; | |
72 | ||
73 | /* holds persistent region state */ | |
74 | struct dirty_log *log; | |
75 | ||
76 | /* hash table */ | |
77 | rwlock_t hash_lock; | |
78 | mempool_t *region_pool; | |
79 | unsigned int mask; | |
80 | unsigned int nr_buckets; | |
81 | struct list_head *buckets; | |
82 | ||
83 | spinlock_t region_lock; | |
84 | struct semaphore recovery_count; | |
85 | struct list_head clean_regions; | |
86 | struct list_head quiesced_regions; | |
87 | struct list_head recovered_regions; | |
88 | }; | |
89 | ||
90 | enum { | |
91 | RH_CLEAN, | |
92 | RH_DIRTY, | |
93 | RH_NOSYNC, | |
94 | RH_RECOVERING | |
95 | }; | |
96 | ||
97 | struct region { | |
98 | struct region_hash *rh; /* FIXME: can we get rid of this ? */ | |
99 | region_t key; | |
100 | int state; | |
101 | ||
102 | struct list_head hash_list; | |
103 | struct list_head list; | |
104 | ||
105 | atomic_t pending; | |
106 | struct bio_list delayed_bios; | |
107 | }; | |
108 | ||
109 | /* | |
110 | * Conversion fns | |
111 | */ | |
112 | static inline region_t bio_to_region(struct region_hash *rh, struct bio *bio) | |
113 | { | |
114 | return bio->bi_sector >> rh->region_shift; | |
115 | } | |
116 | ||
117 | static inline sector_t region_to_sector(struct region_hash *rh, region_t region) | |
118 | { | |
119 | return region << rh->region_shift; | |
120 | } | |
121 | ||
122 | /* FIXME move this */ | |
123 | static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw); | |
124 | ||
dd0fc66f | 125 | static void *region_alloc(gfp_t gfp_mask, void *pool_data) |
1da177e4 LT |
126 | { |
127 | return kmalloc(sizeof(struct region), gfp_mask); | |
128 | } | |
129 | ||
130 | static void region_free(void *element, void *pool_data) | |
131 | { | |
132 | kfree(element); | |
133 | } | |
134 | ||
135 | #define MIN_REGIONS 64 | |
136 | #define MAX_RECOVERY 1 | |
137 | static int rh_init(struct region_hash *rh, struct mirror_set *ms, | |
138 | struct dirty_log *log, uint32_t region_size, | |
139 | region_t nr_regions) | |
140 | { | |
141 | unsigned int nr_buckets, max_buckets; | |
142 | size_t i; | |
143 | ||
144 | /* | |
145 | * Calculate a suitable number of buckets for our hash | |
146 | * table. | |
147 | */ | |
148 | max_buckets = nr_regions >> 6; | |
149 | for (nr_buckets = 128u; nr_buckets < max_buckets; nr_buckets <<= 1) | |
150 | ; | |
151 | nr_buckets >>= 1; | |
152 | ||
153 | rh->ms = ms; | |
154 | rh->log = log; | |
155 | rh->region_size = region_size; | |
156 | rh->region_shift = ffs(region_size) - 1; | |
157 | rwlock_init(&rh->hash_lock); | |
158 | rh->mask = nr_buckets - 1; | |
159 | rh->nr_buckets = nr_buckets; | |
160 | ||
161 | rh->buckets = vmalloc(nr_buckets * sizeof(*rh->buckets)); | |
162 | if (!rh->buckets) { | |
163 | DMERR("unable to allocate region hash memory"); | |
164 | return -ENOMEM; | |
165 | } | |
166 | ||
167 | for (i = 0; i < nr_buckets; i++) | |
168 | INIT_LIST_HEAD(rh->buckets + i); | |
169 | ||
170 | spin_lock_init(&rh->region_lock); | |
171 | sema_init(&rh->recovery_count, 0); | |
172 | INIT_LIST_HEAD(&rh->clean_regions); | |
173 | INIT_LIST_HEAD(&rh->quiesced_regions); | |
174 | INIT_LIST_HEAD(&rh->recovered_regions); | |
175 | ||
176 | rh->region_pool = mempool_create(MIN_REGIONS, region_alloc, | |
177 | region_free, NULL); | |
178 | if (!rh->region_pool) { | |
179 | vfree(rh->buckets); | |
180 | rh->buckets = NULL; | |
181 | return -ENOMEM; | |
182 | } | |
183 | ||
184 | return 0; | |
185 | } | |
186 | ||
187 | static void rh_exit(struct region_hash *rh) | |
188 | { | |
189 | unsigned int h; | |
190 | struct region *reg, *nreg; | |
191 | ||
192 | BUG_ON(!list_empty(&rh->quiesced_regions)); | |
193 | for (h = 0; h < rh->nr_buckets; h++) { | |
194 | list_for_each_entry_safe(reg, nreg, rh->buckets + h, hash_list) { | |
195 | BUG_ON(atomic_read(®->pending)); | |
196 | mempool_free(reg, rh->region_pool); | |
197 | } | |
198 | } | |
199 | ||
200 | if (rh->log) | |
201 | dm_destroy_dirty_log(rh->log); | |
202 | if (rh->region_pool) | |
203 | mempool_destroy(rh->region_pool); | |
204 | vfree(rh->buckets); | |
205 | } | |
206 | ||
207 | #define RH_HASH_MULT 2654435387U | |
208 | ||
209 | static inline unsigned int rh_hash(struct region_hash *rh, region_t region) | |
210 | { | |
211 | return (unsigned int) ((region * RH_HASH_MULT) >> 12) & rh->mask; | |
212 | } | |
213 | ||
214 | static struct region *__rh_lookup(struct region_hash *rh, region_t region) | |
215 | { | |
216 | struct region *reg; | |
217 | ||
218 | list_for_each_entry (reg, rh->buckets + rh_hash(rh, region), hash_list) | |
219 | if (reg->key == region) | |
220 | return reg; | |
221 | ||
222 | return NULL; | |
223 | } | |
224 | ||
225 | static void __rh_insert(struct region_hash *rh, struct region *reg) | |
226 | { | |
227 | unsigned int h = rh_hash(rh, reg->key); | |
228 | list_add(®->hash_list, rh->buckets + h); | |
229 | } | |
230 | ||
231 | static struct region *__rh_alloc(struct region_hash *rh, region_t region) | |
232 | { | |
233 | struct region *reg, *nreg; | |
234 | ||
235 | read_unlock(&rh->hash_lock); | |
236 | nreg = mempool_alloc(rh->region_pool, GFP_NOIO); | |
237 | nreg->state = rh->log->type->in_sync(rh->log, region, 1) ? | |
238 | RH_CLEAN : RH_NOSYNC; | |
239 | nreg->rh = rh; | |
240 | nreg->key = region; | |
241 | ||
242 | INIT_LIST_HEAD(&nreg->list); | |
243 | ||
244 | atomic_set(&nreg->pending, 0); | |
245 | bio_list_init(&nreg->delayed_bios); | |
246 | write_lock_irq(&rh->hash_lock); | |
247 | ||
248 | reg = __rh_lookup(rh, region); | |
249 | if (reg) | |
250 | /* we lost the race */ | |
251 | mempool_free(nreg, rh->region_pool); | |
252 | ||
253 | else { | |
254 | __rh_insert(rh, nreg); | |
255 | if (nreg->state == RH_CLEAN) { | |
256 | spin_lock(&rh->region_lock); | |
257 | list_add(&nreg->list, &rh->clean_regions); | |
258 | spin_unlock(&rh->region_lock); | |
259 | } | |
260 | reg = nreg; | |
261 | } | |
262 | write_unlock_irq(&rh->hash_lock); | |
263 | read_lock(&rh->hash_lock); | |
264 | ||
265 | return reg; | |
266 | } | |
267 | ||
268 | static inline struct region *__rh_find(struct region_hash *rh, region_t region) | |
269 | { | |
270 | struct region *reg; | |
271 | ||
272 | reg = __rh_lookup(rh, region); | |
273 | if (!reg) | |
274 | reg = __rh_alloc(rh, region); | |
275 | ||
276 | return reg; | |
277 | } | |
278 | ||
279 | static int rh_state(struct region_hash *rh, region_t region, int may_block) | |
280 | { | |
281 | int r; | |
282 | struct region *reg; | |
283 | ||
284 | read_lock(&rh->hash_lock); | |
285 | reg = __rh_lookup(rh, region); | |
286 | read_unlock(&rh->hash_lock); | |
287 | ||
288 | if (reg) | |
289 | return reg->state; | |
290 | ||
291 | /* | |
292 | * The region wasn't in the hash, so we fall back to the | |
293 | * dirty log. | |
294 | */ | |
295 | r = rh->log->type->in_sync(rh->log, region, may_block); | |
296 | ||
297 | /* | |
298 | * Any error from the dirty log (eg. -EWOULDBLOCK) gets | |
299 | * taken as a RH_NOSYNC | |
300 | */ | |
301 | return r == 1 ? RH_CLEAN : RH_NOSYNC; | |
302 | } | |
303 | ||
304 | static inline int rh_in_sync(struct region_hash *rh, | |
305 | region_t region, int may_block) | |
306 | { | |
307 | int state = rh_state(rh, region, may_block); | |
308 | return state == RH_CLEAN || state == RH_DIRTY; | |
309 | } | |
310 | ||
311 | static void dispatch_bios(struct mirror_set *ms, struct bio_list *bio_list) | |
312 | { | |
313 | struct bio *bio; | |
314 | ||
315 | while ((bio = bio_list_pop(bio_list))) { | |
316 | queue_bio(ms, bio, WRITE); | |
317 | } | |
318 | } | |
319 | ||
320 | static void rh_update_states(struct region_hash *rh) | |
321 | { | |
322 | struct region *reg, *next; | |
323 | ||
324 | LIST_HEAD(clean); | |
325 | LIST_HEAD(recovered); | |
326 | ||
327 | /* | |
328 | * Quickly grab the lists. | |
329 | */ | |
330 | write_lock_irq(&rh->hash_lock); | |
331 | spin_lock(&rh->region_lock); | |
332 | if (!list_empty(&rh->clean_regions)) { | |
333 | list_splice(&rh->clean_regions, &clean); | |
334 | INIT_LIST_HEAD(&rh->clean_regions); | |
335 | ||
336 | list_for_each_entry (reg, &clean, list) { | |
337 | rh->log->type->clear_region(rh->log, reg->key); | |
338 | list_del(®->hash_list); | |
339 | } | |
340 | } | |
341 | ||
342 | if (!list_empty(&rh->recovered_regions)) { | |
343 | list_splice(&rh->recovered_regions, &recovered); | |
344 | INIT_LIST_HEAD(&rh->recovered_regions); | |
345 | ||
346 | list_for_each_entry (reg, &recovered, list) | |
347 | list_del(®->hash_list); | |
348 | } | |
349 | spin_unlock(&rh->region_lock); | |
350 | write_unlock_irq(&rh->hash_lock); | |
351 | ||
352 | /* | |
353 | * All the regions on the recovered and clean lists have | |
354 | * now been pulled out of the system, so no need to do | |
355 | * any more locking. | |
356 | */ | |
357 | list_for_each_entry_safe (reg, next, &recovered, list) { | |
358 | rh->log->type->clear_region(rh->log, reg->key); | |
359 | rh->log->type->complete_resync_work(rh->log, reg->key, 1); | |
360 | dispatch_bios(rh->ms, ®->delayed_bios); | |
361 | up(&rh->recovery_count); | |
362 | mempool_free(reg, rh->region_pool); | |
363 | } | |
364 | ||
365 | if (!list_empty(&recovered)) | |
366 | rh->log->type->flush(rh->log); | |
367 | ||
368 | list_for_each_entry_safe (reg, next, &clean, list) | |
369 | mempool_free(reg, rh->region_pool); | |
370 | } | |
371 | ||
372 | static void rh_inc(struct region_hash *rh, region_t region) | |
373 | { | |
374 | struct region *reg; | |
375 | ||
376 | read_lock(&rh->hash_lock); | |
377 | reg = __rh_find(rh, region); | |
844e8d90 JN |
378 | |
379 | atomic_inc(®->pending); | |
380 | ||
381 | spin_lock_irq(&rh->region_lock); | |
1da177e4 LT |
382 | if (reg->state == RH_CLEAN) { |
383 | rh->log->type->mark_region(rh->log, reg->key); | |
384 | ||
1da177e4 LT |
385 | reg->state = RH_DIRTY; |
386 | list_del_init(®->list); /* take off the clean list */ | |
1da177e4 | 387 | } |
844e8d90 | 388 | spin_unlock_irq(&rh->region_lock); |
1da177e4 | 389 | |
1da177e4 LT |
390 | read_unlock(&rh->hash_lock); |
391 | } | |
392 | ||
393 | static void rh_inc_pending(struct region_hash *rh, struct bio_list *bios) | |
394 | { | |
395 | struct bio *bio; | |
396 | ||
397 | for (bio = bios->head; bio; bio = bio->bi_next) | |
398 | rh_inc(rh, bio_to_region(rh, bio)); | |
399 | } | |
400 | ||
401 | static void rh_dec(struct region_hash *rh, region_t region) | |
402 | { | |
403 | unsigned long flags; | |
404 | struct region *reg; | |
405 | int should_wake = 0; | |
406 | ||
407 | read_lock(&rh->hash_lock); | |
408 | reg = __rh_lookup(rh, region); | |
409 | read_unlock(&rh->hash_lock); | |
410 | ||
411 | if (atomic_dec_and_test(®->pending)) { | |
412 | spin_lock_irqsave(&rh->region_lock, flags); | |
844e8d90 JN |
413 | if (atomic_read(®->pending)) { /* check race */ |
414 | spin_unlock_irqrestore(&rh->region_lock, flags); | |
415 | return; | |
416 | } | |
1da177e4 LT |
417 | if (reg->state == RH_RECOVERING) { |
418 | list_add_tail(®->list, &rh->quiesced_regions); | |
419 | } else { | |
420 | reg->state = RH_CLEAN; | |
421 | list_add(®->list, &rh->clean_regions); | |
422 | } | |
423 | spin_unlock_irqrestore(&rh->region_lock, flags); | |
424 | should_wake = 1; | |
425 | } | |
426 | ||
427 | if (should_wake) | |
428 | wake(); | |
429 | } | |
430 | ||
431 | /* | |
432 | * Starts quiescing a region in preparation for recovery. | |
433 | */ | |
434 | static int __rh_recovery_prepare(struct region_hash *rh) | |
435 | { | |
436 | int r; | |
437 | struct region *reg; | |
438 | region_t region; | |
439 | ||
440 | /* | |
441 | * Ask the dirty log what's next. | |
442 | */ | |
443 | r = rh->log->type->get_resync_work(rh->log, ®ion); | |
444 | if (r <= 0) | |
445 | return r; | |
446 | ||
447 | /* | |
448 | * Get this region, and start it quiescing by setting the | |
449 | * recovering flag. | |
450 | */ | |
451 | read_lock(&rh->hash_lock); | |
452 | reg = __rh_find(rh, region); | |
453 | read_unlock(&rh->hash_lock); | |
454 | ||
455 | spin_lock_irq(&rh->region_lock); | |
456 | reg->state = RH_RECOVERING; | |
457 | ||
458 | /* Already quiesced ? */ | |
459 | if (atomic_read(®->pending)) | |
460 | list_del_init(®->list); | |
461 | ||
462 | else { | |
463 | list_del_init(®->list); | |
464 | list_add(®->list, &rh->quiesced_regions); | |
465 | } | |
466 | spin_unlock_irq(&rh->region_lock); | |
467 | ||
468 | return 1; | |
469 | } | |
470 | ||
471 | static void rh_recovery_prepare(struct region_hash *rh) | |
472 | { | |
473 | while (!down_trylock(&rh->recovery_count)) | |
474 | if (__rh_recovery_prepare(rh) <= 0) { | |
475 | up(&rh->recovery_count); | |
476 | break; | |
477 | } | |
478 | } | |
479 | ||
480 | /* | |
481 | * Returns any quiesced regions. | |
482 | */ | |
483 | static struct region *rh_recovery_start(struct region_hash *rh) | |
484 | { | |
485 | struct region *reg = NULL; | |
486 | ||
487 | spin_lock_irq(&rh->region_lock); | |
488 | if (!list_empty(&rh->quiesced_regions)) { | |
489 | reg = list_entry(rh->quiesced_regions.next, | |
490 | struct region, list); | |
491 | list_del_init(®->list); /* remove from the quiesced list */ | |
492 | } | |
493 | spin_unlock_irq(&rh->region_lock); | |
494 | ||
495 | return reg; | |
496 | } | |
497 | ||
498 | /* FIXME: success ignored for now */ | |
499 | static void rh_recovery_end(struct region *reg, int success) | |
500 | { | |
501 | struct region_hash *rh = reg->rh; | |
502 | ||
503 | spin_lock_irq(&rh->region_lock); | |
504 | list_add(®->list, ®->rh->recovered_regions); | |
505 | spin_unlock_irq(&rh->region_lock); | |
506 | ||
507 | wake(); | |
508 | } | |
509 | ||
510 | static void rh_flush(struct region_hash *rh) | |
511 | { | |
512 | rh->log->type->flush(rh->log); | |
513 | } | |
514 | ||
515 | static void rh_delay(struct region_hash *rh, struct bio *bio) | |
516 | { | |
517 | struct region *reg; | |
518 | ||
519 | read_lock(&rh->hash_lock); | |
520 | reg = __rh_find(rh, bio_to_region(rh, bio)); | |
521 | bio_list_add(®->delayed_bios, bio); | |
522 | read_unlock(&rh->hash_lock); | |
523 | } | |
524 | ||
525 | static void rh_stop_recovery(struct region_hash *rh) | |
526 | { | |
527 | int i; | |
528 | ||
529 | /* wait for any recovering regions */ | |
530 | for (i = 0; i < MAX_RECOVERY; i++) | |
531 | down(&rh->recovery_count); | |
532 | } | |
533 | ||
534 | static void rh_start_recovery(struct region_hash *rh) | |
535 | { | |
536 | int i; | |
537 | ||
538 | for (i = 0; i < MAX_RECOVERY; i++) | |
539 | up(&rh->recovery_count); | |
540 | ||
541 | wake(); | |
542 | } | |
543 | ||
544 | /*----------------------------------------------------------------- | |
545 | * Mirror set structures. | |
546 | *---------------------------------------------------------------*/ | |
547 | struct mirror { | |
548 | atomic_t error_count; | |
549 | struct dm_dev *dev; | |
550 | sector_t offset; | |
551 | }; | |
552 | ||
553 | struct mirror_set { | |
554 | struct dm_target *ti; | |
555 | struct list_head list; | |
556 | struct region_hash rh; | |
557 | struct kcopyd_client *kcopyd_client; | |
558 | ||
559 | spinlock_t lock; /* protects the next two lists */ | |
560 | struct bio_list reads; | |
561 | struct bio_list writes; | |
562 | ||
563 | /* recovery */ | |
564 | region_t nr_regions; | |
565 | int in_sync; | |
566 | ||
567 | unsigned int nr_mirrors; | |
568 | struct mirror mirror[0]; | |
569 | }; | |
570 | ||
571 | /* | |
572 | * Every mirror should look like this one. | |
573 | */ | |
574 | #define DEFAULT_MIRROR 0 | |
575 | ||
576 | /* | |
577 | * This is yucky. We squirrel the mirror_set struct away inside | |
578 | * bi_next for write buffers. This is safe since the bh | |
579 | * doesn't get submitted to the lower levels of block layer. | |
580 | */ | |
581 | static struct mirror_set *bio_get_ms(struct bio *bio) | |
582 | { | |
583 | return (struct mirror_set *) bio->bi_next; | |
584 | } | |
585 | ||
586 | static void bio_set_ms(struct bio *bio, struct mirror_set *ms) | |
587 | { | |
588 | bio->bi_next = (struct bio *) ms; | |
589 | } | |
590 | ||
591 | /*----------------------------------------------------------------- | |
592 | * Recovery. | |
593 | * | |
594 | * When a mirror is first activated we may find that some regions | |
595 | * are in the no-sync state. We have to recover these by | |
596 | * recopying from the default mirror to all the others. | |
597 | *---------------------------------------------------------------*/ | |
598 | static void recovery_complete(int read_err, unsigned int write_err, | |
599 | void *context) | |
600 | { | |
601 | struct region *reg = (struct region *) context; | |
602 | ||
603 | /* FIXME: better error handling */ | |
604 | rh_recovery_end(reg, read_err || write_err); | |
605 | } | |
606 | ||
607 | static int recover(struct mirror_set *ms, struct region *reg) | |
608 | { | |
609 | int r; | |
610 | unsigned int i; | |
611 | struct io_region from, to[KCOPYD_MAX_REGIONS], *dest; | |
612 | struct mirror *m; | |
613 | unsigned long flags = 0; | |
614 | ||
615 | /* fill in the source */ | |
616 | m = ms->mirror + DEFAULT_MIRROR; | |
617 | from.bdev = m->dev->bdev; | |
618 | from.sector = m->offset + region_to_sector(reg->rh, reg->key); | |
619 | if (reg->key == (ms->nr_regions - 1)) { | |
620 | /* | |
621 | * The final region may be smaller than | |
622 | * region_size. | |
623 | */ | |
624 | from.count = ms->ti->len & (reg->rh->region_size - 1); | |
625 | if (!from.count) | |
626 | from.count = reg->rh->region_size; | |
627 | } else | |
628 | from.count = reg->rh->region_size; | |
629 | ||
630 | /* fill in the destinations */ | |
631 | for (i = 0, dest = to; i < ms->nr_mirrors; i++) { | |
632 | if (i == DEFAULT_MIRROR) | |
633 | continue; | |
634 | ||
635 | m = ms->mirror + i; | |
636 | dest->bdev = m->dev->bdev; | |
637 | dest->sector = m->offset + region_to_sector(reg->rh, reg->key); | |
638 | dest->count = from.count; | |
639 | dest++; | |
640 | } | |
641 | ||
642 | /* hand to kcopyd */ | |
643 | set_bit(KCOPYD_IGNORE_ERROR, &flags); | |
644 | r = kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, flags, | |
645 | recovery_complete, reg); | |
646 | ||
647 | return r; | |
648 | } | |
649 | ||
650 | static void do_recovery(struct mirror_set *ms) | |
651 | { | |
652 | int r; | |
653 | struct region *reg; | |
654 | struct dirty_log *log = ms->rh.log; | |
655 | ||
656 | /* | |
657 | * Start quiescing some regions. | |
658 | */ | |
659 | rh_recovery_prepare(&ms->rh); | |
660 | ||
661 | /* | |
662 | * Copy any already quiesced regions. | |
663 | */ | |
664 | while ((reg = rh_recovery_start(&ms->rh))) { | |
665 | r = recover(ms, reg); | |
666 | if (r) | |
667 | rh_recovery_end(reg, 0); | |
668 | } | |
669 | ||
670 | /* | |
671 | * Update the in sync flag. | |
672 | */ | |
673 | if (!ms->in_sync && | |
674 | (log->type->get_sync_count(log) == ms->nr_regions)) { | |
675 | /* the sync is complete */ | |
676 | dm_table_event(ms->ti->table); | |
677 | ms->in_sync = 1; | |
678 | } | |
679 | } | |
680 | ||
681 | /*----------------------------------------------------------------- | |
682 | * Reads | |
683 | *---------------------------------------------------------------*/ | |
684 | static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector) | |
685 | { | |
686 | /* FIXME: add read balancing */ | |
687 | return ms->mirror + DEFAULT_MIRROR; | |
688 | } | |
689 | ||
690 | /* | |
691 | * remap a buffer to a particular mirror. | |
692 | */ | |
693 | static void map_bio(struct mirror_set *ms, struct mirror *m, struct bio *bio) | |
694 | { | |
695 | bio->bi_bdev = m->dev->bdev; | |
696 | bio->bi_sector = m->offset + (bio->bi_sector - ms->ti->begin); | |
697 | } | |
698 | ||
699 | static void do_reads(struct mirror_set *ms, struct bio_list *reads) | |
700 | { | |
701 | region_t region; | |
702 | struct bio *bio; | |
703 | struct mirror *m; | |
704 | ||
705 | while ((bio = bio_list_pop(reads))) { | |
706 | region = bio_to_region(&ms->rh, bio); | |
707 | ||
708 | /* | |
709 | * We can only read balance if the region is in sync. | |
710 | */ | |
711 | if (rh_in_sync(&ms->rh, region, 0)) | |
712 | m = choose_mirror(ms, bio->bi_sector); | |
713 | else | |
714 | m = ms->mirror + DEFAULT_MIRROR; | |
715 | ||
716 | map_bio(ms, m, bio); | |
717 | generic_make_request(bio); | |
718 | } | |
719 | } | |
720 | ||
721 | /*----------------------------------------------------------------- | |
722 | * Writes. | |
723 | * | |
724 | * We do different things with the write io depending on the | |
725 | * state of the region that it's in: | |
726 | * | |
727 | * SYNC: increment pending, use kcopyd to write to *all* mirrors | |
728 | * RECOVERING: delay the io until recovery completes | |
729 | * NOSYNC: increment pending, just write to the default mirror | |
730 | *---------------------------------------------------------------*/ | |
731 | static void write_callback(unsigned long error, void *context) | |
732 | { | |
733 | unsigned int i; | |
734 | int uptodate = 1; | |
735 | struct bio *bio = (struct bio *) context; | |
736 | struct mirror_set *ms; | |
737 | ||
738 | ms = bio_get_ms(bio); | |
739 | bio_set_ms(bio, NULL); | |
740 | ||
741 | /* | |
742 | * NOTE: We don't decrement the pending count here, | |
743 | * instead it is done by the targets endio function. | |
744 | * This way we handle both writes to SYNC and NOSYNC | |
745 | * regions with the same code. | |
746 | */ | |
747 | ||
748 | if (error) { | |
749 | /* | |
750 | * only error the io if all mirrors failed. | |
751 | * FIXME: bogus | |
752 | */ | |
753 | uptodate = 0; | |
754 | for (i = 0; i < ms->nr_mirrors; i++) | |
755 | if (!test_bit(i, &error)) { | |
756 | uptodate = 1; | |
757 | break; | |
758 | } | |
759 | } | |
760 | bio_endio(bio, bio->bi_size, 0); | |
761 | } | |
762 | ||
763 | static void do_write(struct mirror_set *ms, struct bio *bio) | |
764 | { | |
765 | unsigned int i; | |
766 | struct io_region io[KCOPYD_MAX_REGIONS+1]; | |
767 | struct mirror *m; | |
768 | ||
769 | for (i = 0; i < ms->nr_mirrors; i++) { | |
770 | m = ms->mirror + i; | |
771 | ||
772 | io[i].bdev = m->dev->bdev; | |
773 | io[i].sector = m->offset + (bio->bi_sector - ms->ti->begin); | |
774 | io[i].count = bio->bi_size >> 9; | |
775 | } | |
776 | ||
777 | bio_set_ms(bio, ms); | |
778 | dm_io_async_bvec(ms->nr_mirrors, io, WRITE, | |
779 | bio->bi_io_vec + bio->bi_idx, | |
780 | write_callback, bio); | |
781 | } | |
782 | ||
783 | static void do_writes(struct mirror_set *ms, struct bio_list *writes) | |
784 | { | |
785 | int state; | |
786 | struct bio *bio; | |
787 | struct bio_list sync, nosync, recover, *this_list = NULL; | |
788 | ||
789 | if (!writes->head) | |
790 | return; | |
791 | ||
792 | /* | |
793 | * Classify each write. | |
794 | */ | |
795 | bio_list_init(&sync); | |
796 | bio_list_init(&nosync); | |
797 | bio_list_init(&recover); | |
798 | ||
799 | while ((bio = bio_list_pop(writes))) { | |
800 | state = rh_state(&ms->rh, bio_to_region(&ms->rh, bio), 1); | |
801 | switch (state) { | |
802 | case RH_CLEAN: | |
803 | case RH_DIRTY: | |
804 | this_list = &sync; | |
805 | break; | |
806 | ||
807 | case RH_NOSYNC: | |
808 | this_list = &nosync; | |
809 | break; | |
810 | ||
811 | case RH_RECOVERING: | |
812 | this_list = &recover; | |
813 | break; | |
814 | } | |
815 | ||
816 | bio_list_add(this_list, bio); | |
817 | } | |
818 | ||
819 | /* | |
820 | * Increment the pending counts for any regions that will | |
821 | * be written to (writes to recover regions are going to | |
822 | * be delayed). | |
823 | */ | |
824 | rh_inc_pending(&ms->rh, &sync); | |
825 | rh_inc_pending(&ms->rh, &nosync); | |
826 | rh_flush(&ms->rh); | |
827 | ||
828 | /* | |
829 | * Dispatch io. | |
830 | */ | |
831 | while ((bio = bio_list_pop(&sync))) | |
832 | do_write(ms, bio); | |
833 | ||
834 | while ((bio = bio_list_pop(&recover))) | |
835 | rh_delay(&ms->rh, bio); | |
836 | ||
837 | while ((bio = bio_list_pop(&nosync))) { | |
838 | map_bio(ms, ms->mirror + DEFAULT_MIRROR, bio); | |
839 | generic_make_request(bio); | |
840 | } | |
841 | } | |
842 | ||
843 | /*----------------------------------------------------------------- | |
844 | * kmirrord | |
845 | *---------------------------------------------------------------*/ | |
846 | static LIST_HEAD(_mirror_sets); | |
847 | static DECLARE_RWSEM(_mirror_sets_lock); | |
848 | ||
849 | static void do_mirror(struct mirror_set *ms) | |
850 | { | |
851 | struct bio_list reads, writes; | |
852 | ||
853 | spin_lock(&ms->lock); | |
854 | reads = ms->reads; | |
855 | writes = ms->writes; | |
856 | bio_list_init(&ms->reads); | |
857 | bio_list_init(&ms->writes); | |
858 | spin_unlock(&ms->lock); | |
859 | ||
860 | rh_update_states(&ms->rh); | |
861 | do_recovery(ms); | |
862 | do_reads(ms, &reads); | |
863 | do_writes(ms, &writes); | |
864 | } | |
865 | ||
866 | static void do_work(void *ignored) | |
867 | { | |
868 | struct mirror_set *ms; | |
869 | ||
870 | down_read(&_mirror_sets_lock); | |
871 | list_for_each_entry (ms, &_mirror_sets, list) | |
872 | do_mirror(ms); | |
873 | up_read(&_mirror_sets_lock); | |
874 | } | |
875 | ||
876 | /*----------------------------------------------------------------- | |
877 | * Target functions | |
878 | *---------------------------------------------------------------*/ | |
879 | static struct mirror_set *alloc_context(unsigned int nr_mirrors, | |
880 | uint32_t region_size, | |
881 | struct dm_target *ti, | |
882 | struct dirty_log *dl) | |
883 | { | |
884 | size_t len; | |
885 | struct mirror_set *ms = NULL; | |
886 | ||
887 | if (array_too_big(sizeof(*ms), sizeof(ms->mirror[0]), nr_mirrors)) | |
888 | return NULL; | |
889 | ||
890 | len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors); | |
891 | ||
892 | ms = kmalloc(len, GFP_KERNEL); | |
893 | if (!ms) { | |
894 | ti->error = "dm-mirror: Cannot allocate mirror context"; | |
895 | return NULL; | |
896 | } | |
897 | ||
898 | memset(ms, 0, len); | |
899 | spin_lock_init(&ms->lock); | |
900 | ||
901 | ms->ti = ti; | |
902 | ms->nr_mirrors = nr_mirrors; | |
903 | ms->nr_regions = dm_sector_div_up(ti->len, region_size); | |
904 | ms->in_sync = 0; | |
905 | ||
906 | if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) { | |
907 | ti->error = "dm-mirror: Error creating dirty region hash"; | |
908 | kfree(ms); | |
909 | return NULL; | |
910 | } | |
911 | ||
912 | return ms; | |
913 | } | |
914 | ||
915 | static void free_context(struct mirror_set *ms, struct dm_target *ti, | |
916 | unsigned int m) | |
917 | { | |
918 | while (m--) | |
919 | dm_put_device(ti, ms->mirror[m].dev); | |
920 | ||
921 | rh_exit(&ms->rh); | |
922 | kfree(ms); | |
923 | } | |
924 | ||
925 | static inline int _check_region_size(struct dm_target *ti, uint32_t size) | |
926 | { | |
927 | return !(size % (PAGE_SIZE >> 9) || (size & (size - 1)) || | |
928 | size > ti->len); | |
929 | } | |
930 | ||
931 | static int get_mirror(struct mirror_set *ms, struct dm_target *ti, | |
932 | unsigned int mirror, char **argv) | |
933 | { | |
934 | sector_t offset; | |
935 | ||
936 | if (sscanf(argv[1], SECTOR_FORMAT, &offset) != 1) { | |
937 | ti->error = "dm-mirror: Invalid offset"; | |
938 | return -EINVAL; | |
939 | } | |
940 | ||
941 | if (dm_get_device(ti, argv[0], offset, ti->len, | |
942 | dm_table_get_mode(ti->table), | |
943 | &ms->mirror[mirror].dev)) { | |
944 | ti->error = "dm-mirror: Device lookup failure"; | |
945 | return -ENXIO; | |
946 | } | |
947 | ||
948 | ms->mirror[mirror].offset = offset; | |
949 | ||
950 | return 0; | |
951 | } | |
952 | ||
953 | static int add_mirror_set(struct mirror_set *ms) | |
954 | { | |
955 | down_write(&_mirror_sets_lock); | |
956 | list_add_tail(&ms->list, &_mirror_sets); | |
957 | up_write(&_mirror_sets_lock); | |
958 | wake(); | |
959 | ||
960 | return 0; | |
961 | } | |
962 | ||
963 | static void del_mirror_set(struct mirror_set *ms) | |
964 | { | |
965 | down_write(&_mirror_sets_lock); | |
966 | list_del(&ms->list); | |
967 | up_write(&_mirror_sets_lock); | |
968 | } | |
969 | ||
970 | /* | |
971 | * Create dirty log: log_type #log_params <log_params> | |
972 | */ | |
973 | static struct dirty_log *create_dirty_log(struct dm_target *ti, | |
974 | unsigned int argc, char **argv, | |
975 | unsigned int *args_used) | |
976 | { | |
977 | unsigned int param_count; | |
978 | struct dirty_log *dl; | |
979 | ||
980 | if (argc < 2) { | |
981 | ti->error = "dm-mirror: Insufficient mirror log arguments"; | |
982 | return NULL; | |
983 | } | |
984 | ||
985 | if (sscanf(argv[1], "%u", ¶m_count) != 1) { | |
986 | ti->error = "dm-mirror: Invalid mirror log argument count"; | |
987 | return NULL; | |
988 | } | |
989 | ||
990 | *args_used = 2 + param_count; | |
991 | ||
992 | if (argc < *args_used) { | |
993 | ti->error = "dm-mirror: Insufficient mirror log arguments"; | |
994 | return NULL; | |
995 | } | |
996 | ||
997 | dl = dm_create_dirty_log(argv[0], ti, param_count, argv + 2); | |
998 | if (!dl) { | |
999 | ti->error = "dm-mirror: Error creating mirror dirty log"; | |
1000 | return NULL; | |
1001 | } | |
1002 | ||
1003 | if (!_check_region_size(ti, dl->type->get_region_size(dl))) { | |
1004 | ti->error = "dm-mirror: Invalid region size"; | |
1005 | dm_destroy_dirty_log(dl); | |
1006 | return NULL; | |
1007 | } | |
1008 | ||
1009 | return dl; | |
1010 | } | |
1011 | ||
1012 | /* | |
1013 | * Construct a mirror mapping: | |
1014 | * | |
1015 | * log_type #log_params <log_params> | |
1016 | * #mirrors [mirror_path offset]{2,} | |
1017 | * | |
1018 | * log_type is "core" or "disk" | |
1019 | * #log_params is between 1 and 3 | |
1020 | */ | |
1021 | #define DM_IO_PAGES 64 | |
1022 | static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
1023 | { | |
1024 | int r; | |
1025 | unsigned int nr_mirrors, m, args_used; | |
1026 | struct mirror_set *ms; | |
1027 | struct dirty_log *dl; | |
1028 | ||
1029 | dl = create_dirty_log(ti, argc, argv, &args_used); | |
1030 | if (!dl) | |
1031 | return -EINVAL; | |
1032 | ||
1033 | argv += args_used; | |
1034 | argc -= args_used; | |
1035 | ||
1036 | if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 || | |
1037 | nr_mirrors < 2 || nr_mirrors > KCOPYD_MAX_REGIONS + 1) { | |
1038 | ti->error = "dm-mirror: Invalid number of mirrors"; | |
1039 | dm_destroy_dirty_log(dl); | |
1040 | return -EINVAL; | |
1041 | } | |
1042 | ||
1043 | argv++, argc--; | |
1044 | ||
1045 | if (argc != nr_mirrors * 2) { | |
1046 | ti->error = "dm-mirror: Wrong number of mirror arguments"; | |
1047 | dm_destroy_dirty_log(dl); | |
1048 | return -EINVAL; | |
1049 | } | |
1050 | ||
1051 | ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl); | |
1052 | if (!ms) { | |
1053 | dm_destroy_dirty_log(dl); | |
1054 | return -ENOMEM; | |
1055 | } | |
1056 | ||
1057 | /* Get the mirror parameter sets */ | |
1058 | for (m = 0; m < nr_mirrors; m++) { | |
1059 | r = get_mirror(ms, ti, m, argv); | |
1060 | if (r) { | |
1061 | free_context(ms, ti, m); | |
1062 | return r; | |
1063 | } | |
1064 | argv += 2; | |
1065 | argc -= 2; | |
1066 | } | |
1067 | ||
1068 | ti->private = ms; | |
d88854f0 | 1069 | ti->split_io = ms->rh.region_size; |
1da177e4 LT |
1070 | |
1071 | r = kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client); | |
1072 | if (r) { | |
1073 | free_context(ms, ti, ms->nr_mirrors); | |
1074 | return r; | |
1075 | } | |
1076 | ||
1077 | add_mirror_set(ms); | |
1078 | return 0; | |
1079 | } | |
1080 | ||
1081 | static void mirror_dtr(struct dm_target *ti) | |
1082 | { | |
1083 | struct mirror_set *ms = (struct mirror_set *) ti->private; | |
1084 | ||
1085 | del_mirror_set(ms); | |
1086 | kcopyd_client_destroy(ms->kcopyd_client); | |
1087 | free_context(ms, ti, ms->nr_mirrors); | |
1088 | } | |
1089 | ||
1090 | static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw) | |
1091 | { | |
1092 | int should_wake = 0; | |
1093 | struct bio_list *bl; | |
1094 | ||
1095 | bl = (rw == WRITE) ? &ms->writes : &ms->reads; | |
1096 | spin_lock(&ms->lock); | |
1097 | should_wake = !(bl->head); | |
1098 | bio_list_add(bl, bio); | |
1099 | spin_unlock(&ms->lock); | |
1100 | ||
1101 | if (should_wake) | |
1102 | wake(); | |
1103 | } | |
1104 | ||
1105 | /* | |
1106 | * Mirror mapping function | |
1107 | */ | |
1108 | static int mirror_map(struct dm_target *ti, struct bio *bio, | |
1109 | union map_info *map_context) | |
1110 | { | |
1111 | int r, rw = bio_rw(bio); | |
1112 | struct mirror *m; | |
1113 | struct mirror_set *ms = ti->private; | |
1114 | ||
1115 | map_context->ll = bio->bi_sector >> ms->rh.region_shift; | |
1116 | ||
1117 | if (rw == WRITE) { | |
1118 | queue_bio(ms, bio, rw); | |
1119 | return 0; | |
1120 | } | |
1121 | ||
1122 | r = ms->rh.log->type->in_sync(ms->rh.log, | |
1123 | bio_to_region(&ms->rh, bio), 0); | |
1124 | if (r < 0 && r != -EWOULDBLOCK) | |
1125 | return r; | |
1126 | ||
1127 | if (r == -EWOULDBLOCK) /* FIXME: ugly */ | |
1128 | r = 0; | |
1129 | ||
1130 | /* | |
1131 | * We don't want to fast track a recovery just for a read | |
1132 | * ahead. So we just let it silently fail. | |
1133 | * FIXME: get rid of this. | |
1134 | */ | |
1135 | if (!r && rw == READA) | |
1136 | return -EIO; | |
1137 | ||
1138 | if (!r) { | |
1139 | /* Pass this io over to the daemon */ | |
1140 | queue_bio(ms, bio, rw); | |
1141 | return 0; | |
1142 | } | |
1143 | ||
1144 | m = choose_mirror(ms, bio->bi_sector); | |
1145 | if (!m) | |
1146 | return -EIO; | |
1147 | ||
1148 | map_bio(ms, m, bio); | |
1149 | return 1; | |
1150 | } | |
1151 | ||
1152 | static int mirror_end_io(struct dm_target *ti, struct bio *bio, | |
1153 | int error, union map_info *map_context) | |
1154 | { | |
1155 | int rw = bio_rw(bio); | |
1156 | struct mirror_set *ms = (struct mirror_set *) ti->private; | |
1157 | region_t region = map_context->ll; | |
1158 | ||
1159 | /* | |
1160 | * We need to dec pending if this was a write. | |
1161 | */ | |
1162 | if (rw == WRITE) | |
1163 | rh_dec(&ms->rh, region); | |
1164 | ||
1165 | return 0; | |
1166 | } | |
1167 | ||
1168 | static void mirror_postsuspend(struct dm_target *ti) | |
1169 | { | |
1170 | struct mirror_set *ms = (struct mirror_set *) ti->private; | |
1171 | struct dirty_log *log = ms->rh.log; | |
1172 | ||
1173 | rh_stop_recovery(&ms->rh); | |
1174 | if (log->type->suspend && log->type->suspend(log)) | |
1175 | /* FIXME: need better error handling */ | |
1176 | DMWARN("log suspend failed"); | |
1177 | } | |
1178 | ||
1179 | static void mirror_resume(struct dm_target *ti) | |
1180 | { | |
1181 | struct mirror_set *ms = (struct mirror_set *) ti->private; | |
1182 | struct dirty_log *log = ms->rh.log; | |
1183 | if (log->type->resume && log->type->resume(log)) | |
1184 | /* FIXME: need better error handling */ | |
1185 | DMWARN("log resume failed"); | |
1186 | rh_start_recovery(&ms->rh); | |
1187 | } | |
1188 | ||
1189 | static int mirror_status(struct dm_target *ti, status_type_t type, | |
1190 | char *result, unsigned int maxlen) | |
1191 | { | |
1192 | unsigned int m, sz; | |
1193 | struct mirror_set *ms = (struct mirror_set *) ti->private; | |
1194 | ||
1195 | sz = ms->rh.log->type->status(ms->rh.log, type, result, maxlen); | |
1196 | ||
1197 | switch (type) { | |
1198 | case STATUSTYPE_INFO: | |
1199 | DMEMIT("%d ", ms->nr_mirrors); | |
1200 | for (m = 0; m < ms->nr_mirrors; m++) | |
1201 | DMEMIT("%s ", ms->mirror[m].dev->name); | |
1202 | ||
1203 | DMEMIT(SECTOR_FORMAT "/" SECTOR_FORMAT, | |
1204 | ms->rh.log->type->get_sync_count(ms->rh.log), | |
1205 | ms->nr_regions); | |
1206 | break; | |
1207 | ||
1208 | case STATUSTYPE_TABLE: | |
1209 | DMEMIT("%d ", ms->nr_mirrors); | |
1210 | for (m = 0; m < ms->nr_mirrors; m++) | |
1211 | DMEMIT("%s " SECTOR_FORMAT " ", | |
1212 | ms->mirror[m].dev->name, ms->mirror[m].offset); | |
1213 | } | |
1214 | ||
1215 | return 0; | |
1216 | } | |
1217 | ||
1218 | static struct target_type mirror_target = { | |
1219 | .name = "mirror", | |
1220 | .version = {1, 0, 1}, | |
1221 | .module = THIS_MODULE, | |
1222 | .ctr = mirror_ctr, | |
1223 | .dtr = mirror_dtr, | |
1224 | .map = mirror_map, | |
1225 | .end_io = mirror_end_io, | |
1226 | .postsuspend = mirror_postsuspend, | |
1227 | .resume = mirror_resume, | |
1228 | .status = mirror_status, | |
1229 | }; | |
1230 | ||
1231 | static int __init dm_mirror_init(void) | |
1232 | { | |
1233 | int r; | |
1234 | ||
1235 | r = dm_dirty_log_init(); | |
1236 | if (r) | |
1237 | return r; | |
1238 | ||
48f1f532 | 1239 | _kmirrord_wq = create_singlethread_workqueue("kmirrord"); |
1da177e4 LT |
1240 | if (!_kmirrord_wq) { |
1241 | DMERR("couldn't start kmirrord"); | |
1242 | dm_dirty_log_exit(); | |
1243 | return r; | |
1244 | } | |
1245 | INIT_WORK(&_kmirrord_work, do_work, NULL); | |
1246 | ||
1247 | r = dm_register_target(&mirror_target); | |
1248 | if (r < 0) { | |
1249 | DMERR("%s: Failed to register mirror target", | |
1250 | mirror_target.name); | |
1251 | dm_dirty_log_exit(); | |
1252 | destroy_workqueue(_kmirrord_wq); | |
1253 | } | |
1254 | ||
1255 | return r; | |
1256 | } | |
1257 | ||
1258 | static void __exit dm_mirror_exit(void) | |
1259 | { | |
1260 | int r; | |
1261 | ||
1262 | r = dm_unregister_target(&mirror_target); | |
1263 | if (r < 0) | |
1264 | DMERR("%s: unregister failed %d", mirror_target.name, r); | |
1265 | ||
1266 | destroy_workqueue(_kmirrord_wq); | |
1267 | dm_dirty_log_exit(); | |
1268 | } | |
1269 | ||
1270 | /* Module hooks */ | |
1271 | module_init(dm_mirror_init); | |
1272 | module_exit(dm_mirror_exit); | |
1273 | ||
1274 | MODULE_DESCRIPTION(DM_NAME " mirror target"); | |
1275 | MODULE_AUTHOR("Joe Thornber"); | |
1276 | MODULE_LICENSE("GPL"); |