Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * dm-snapshot.c | |
3 | * | |
4 | * Copyright (C) 2001-2002 Sistina Software (UK) Limited. | |
5 | * | |
6 | * This file is released under the GPL. | |
7 | */ | |
8 | ||
9 | #include <linux/blkdev.h> | |
10 | #include <linux/config.h> | |
11 | #include <linux/ctype.h> | |
12 | #include <linux/device-mapper.h> | |
13 | #include <linux/fs.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/kdev_t.h> | |
16 | #include <linux/list.h> | |
17 | #include <linux/mempool.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/vmalloc.h> | |
21 | ||
22 | #include "dm-snap.h" | |
23 | #include "dm-bio-list.h" | |
24 | #include "kcopyd.h" | |
25 | ||
72d94861 AK |
26 | #define DM_MSG_PREFIX "snapshots" |
27 | ||
1da177e4 LT |
28 | /* |
29 | * The percentage increment we will wake up users at | |
30 | */ | |
31 | #define WAKE_UP_PERCENT 5 | |
32 | ||
33 | /* | |
34 | * kcopyd priority of snapshot operations | |
35 | */ | |
36 | #define SNAPSHOT_COPY_PRIORITY 2 | |
37 | ||
38 | /* | |
39 | * Each snapshot reserves this many pages for io | |
40 | */ | |
41 | #define SNAPSHOT_PAGES 256 | |
42 | ||
43 | struct pending_exception { | |
44 | struct exception e; | |
45 | ||
46 | /* | |
47 | * Origin buffers waiting for this to complete are held | |
48 | * in a bio list | |
49 | */ | |
50 | struct bio_list origin_bios; | |
51 | struct bio_list snapshot_bios; | |
52 | ||
eccf0817 AK |
53 | /* |
54 | * Short-term queue of pending exceptions prior to submission. | |
55 | */ | |
56 | struct list_head list; | |
57 | ||
1da177e4 | 58 | /* |
b4b610f6 AK |
59 | * The primary pending_exception is the one that holds |
60 | * the sibling_count and the list of origin_bios for a | |
61 | * group of pending_exceptions. It is always last to get freed. | |
62 | * These fields get set up when writing to the origin. | |
1da177e4 | 63 | */ |
b4b610f6 AK |
64 | struct pending_exception *primary_pe; |
65 | ||
66 | /* | |
67 | * Number of pending_exceptions processing this chunk. | |
68 | * When this drops to zero we must complete the origin bios. | |
69 | * If incrementing or decrementing this, hold pe->snap->lock for | |
70 | * the sibling concerned and not pe->primary_pe->snap->lock unless | |
71 | * they are the same. | |
72 | */ | |
73 | atomic_t sibling_count; | |
1da177e4 LT |
74 | |
75 | /* Pointer back to snapshot context */ | |
76 | struct dm_snapshot *snap; | |
77 | ||
78 | /* | |
79 | * 1 indicates the exception has already been sent to | |
80 | * kcopyd. | |
81 | */ | |
82 | int started; | |
83 | }; | |
84 | ||
85 | /* | |
86 | * Hash table mapping origin volumes to lists of snapshots and | |
87 | * a lock to protect it | |
88 | */ | |
89 | static kmem_cache_t *exception_cache; | |
90 | static kmem_cache_t *pending_cache; | |
91 | static mempool_t *pending_pool; | |
92 | ||
93 | /* | |
94 | * One of these per registered origin, held in the snapshot_origins hash | |
95 | */ | |
96 | struct origin { | |
97 | /* The origin device */ | |
98 | struct block_device *bdev; | |
99 | ||
100 | struct list_head hash_list; | |
101 | ||
102 | /* List of snapshots for this origin */ | |
103 | struct list_head snapshots; | |
104 | }; | |
105 | ||
106 | /* | |
107 | * Size of the hash table for origin volumes. If we make this | |
108 | * the size of the minors list then it should be nearly perfect | |
109 | */ | |
110 | #define ORIGIN_HASH_SIZE 256 | |
111 | #define ORIGIN_MASK 0xFF | |
112 | static struct list_head *_origins; | |
113 | static struct rw_semaphore _origins_lock; | |
114 | ||
115 | static int init_origin_hash(void) | |
116 | { | |
117 | int i; | |
118 | ||
119 | _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), | |
120 | GFP_KERNEL); | |
121 | if (!_origins) { | |
72d94861 | 122 | DMERR("unable to allocate memory"); |
1da177e4 LT |
123 | return -ENOMEM; |
124 | } | |
125 | ||
126 | for (i = 0; i < ORIGIN_HASH_SIZE; i++) | |
127 | INIT_LIST_HEAD(_origins + i); | |
128 | init_rwsem(&_origins_lock); | |
129 | ||
130 | return 0; | |
131 | } | |
132 | ||
133 | static void exit_origin_hash(void) | |
134 | { | |
135 | kfree(_origins); | |
136 | } | |
137 | ||
138 | static inline unsigned int origin_hash(struct block_device *bdev) | |
139 | { | |
140 | return bdev->bd_dev & ORIGIN_MASK; | |
141 | } | |
142 | ||
143 | static struct origin *__lookup_origin(struct block_device *origin) | |
144 | { | |
145 | struct list_head *ol; | |
146 | struct origin *o; | |
147 | ||
148 | ol = &_origins[origin_hash(origin)]; | |
149 | list_for_each_entry (o, ol, hash_list) | |
150 | if (bdev_equal(o->bdev, origin)) | |
151 | return o; | |
152 | ||
153 | return NULL; | |
154 | } | |
155 | ||
156 | static void __insert_origin(struct origin *o) | |
157 | { | |
158 | struct list_head *sl = &_origins[origin_hash(o->bdev)]; | |
159 | list_add_tail(&o->hash_list, sl); | |
160 | } | |
161 | ||
162 | /* | |
163 | * Make a note of the snapshot and its origin so we can look it | |
164 | * up when the origin has a write on it. | |
165 | */ | |
166 | static int register_snapshot(struct dm_snapshot *snap) | |
167 | { | |
168 | struct origin *o; | |
169 | struct block_device *bdev = snap->origin->bdev; | |
170 | ||
171 | down_write(&_origins_lock); | |
172 | o = __lookup_origin(bdev); | |
173 | ||
174 | if (!o) { | |
175 | /* New origin */ | |
176 | o = kmalloc(sizeof(*o), GFP_KERNEL); | |
177 | if (!o) { | |
178 | up_write(&_origins_lock); | |
179 | return -ENOMEM; | |
180 | } | |
181 | ||
182 | /* Initialise the struct */ | |
183 | INIT_LIST_HEAD(&o->snapshots); | |
184 | o->bdev = bdev; | |
185 | ||
186 | __insert_origin(o); | |
187 | } | |
188 | ||
189 | list_add_tail(&snap->list, &o->snapshots); | |
190 | ||
191 | up_write(&_origins_lock); | |
192 | return 0; | |
193 | } | |
194 | ||
195 | static void unregister_snapshot(struct dm_snapshot *s) | |
196 | { | |
197 | struct origin *o; | |
198 | ||
199 | down_write(&_origins_lock); | |
200 | o = __lookup_origin(s->origin->bdev); | |
201 | ||
202 | list_del(&s->list); | |
203 | if (list_empty(&o->snapshots)) { | |
204 | list_del(&o->hash_list); | |
205 | kfree(o); | |
206 | } | |
207 | ||
208 | up_write(&_origins_lock); | |
209 | } | |
210 | ||
211 | /* | |
212 | * Implementation of the exception hash tables. | |
213 | */ | |
214 | static int init_exception_table(struct exception_table *et, uint32_t size) | |
215 | { | |
216 | unsigned int i; | |
217 | ||
218 | et->hash_mask = size - 1; | |
219 | et->table = dm_vcalloc(size, sizeof(struct list_head)); | |
220 | if (!et->table) | |
221 | return -ENOMEM; | |
222 | ||
223 | for (i = 0; i < size; i++) | |
224 | INIT_LIST_HEAD(et->table + i); | |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
229 | static void exit_exception_table(struct exception_table *et, kmem_cache_t *mem) | |
230 | { | |
231 | struct list_head *slot; | |
232 | struct exception *ex, *next; | |
233 | int i, size; | |
234 | ||
235 | size = et->hash_mask + 1; | |
236 | for (i = 0; i < size; i++) { | |
237 | slot = et->table + i; | |
238 | ||
239 | list_for_each_entry_safe (ex, next, slot, hash_list) | |
240 | kmem_cache_free(mem, ex); | |
241 | } | |
242 | ||
243 | vfree(et->table); | |
244 | } | |
245 | ||
246 | static inline uint32_t exception_hash(struct exception_table *et, chunk_t chunk) | |
247 | { | |
248 | return chunk & et->hash_mask; | |
249 | } | |
250 | ||
251 | static void insert_exception(struct exception_table *eh, struct exception *e) | |
252 | { | |
253 | struct list_head *l = &eh->table[exception_hash(eh, e->old_chunk)]; | |
254 | list_add(&e->hash_list, l); | |
255 | } | |
256 | ||
257 | static inline void remove_exception(struct exception *e) | |
258 | { | |
259 | list_del(&e->hash_list); | |
260 | } | |
261 | ||
262 | /* | |
263 | * Return the exception data for a sector, or NULL if not | |
264 | * remapped. | |
265 | */ | |
266 | static struct exception *lookup_exception(struct exception_table *et, | |
267 | chunk_t chunk) | |
268 | { | |
269 | struct list_head *slot; | |
270 | struct exception *e; | |
271 | ||
272 | slot = &et->table[exception_hash(et, chunk)]; | |
273 | list_for_each_entry (e, slot, hash_list) | |
274 | if (e->old_chunk == chunk) | |
275 | return e; | |
276 | ||
277 | return NULL; | |
278 | } | |
279 | ||
280 | static inline struct exception *alloc_exception(void) | |
281 | { | |
282 | struct exception *e; | |
283 | ||
284 | e = kmem_cache_alloc(exception_cache, GFP_NOIO); | |
285 | if (!e) | |
286 | e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); | |
287 | ||
288 | return e; | |
289 | } | |
290 | ||
291 | static inline void free_exception(struct exception *e) | |
292 | { | |
293 | kmem_cache_free(exception_cache, e); | |
294 | } | |
295 | ||
296 | static inline struct pending_exception *alloc_pending_exception(void) | |
297 | { | |
298 | return mempool_alloc(pending_pool, GFP_NOIO); | |
299 | } | |
300 | ||
301 | static inline void free_pending_exception(struct pending_exception *pe) | |
302 | { | |
303 | mempool_free(pe, pending_pool); | |
304 | } | |
305 | ||
306 | int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new) | |
307 | { | |
308 | struct exception *e; | |
309 | ||
310 | e = alloc_exception(); | |
311 | if (!e) | |
312 | return -ENOMEM; | |
313 | ||
314 | e->old_chunk = old; | |
315 | e->new_chunk = new; | |
316 | insert_exception(&s->complete, e); | |
317 | return 0; | |
318 | } | |
319 | ||
320 | /* | |
321 | * Hard coded magic. | |
322 | */ | |
323 | static int calc_max_buckets(void) | |
324 | { | |
325 | /* use a fixed size of 2MB */ | |
326 | unsigned long mem = 2 * 1024 * 1024; | |
327 | mem /= sizeof(struct list_head); | |
328 | ||
329 | return mem; | |
330 | } | |
331 | ||
332 | /* | |
333 | * Rounds a number down to a power of 2. | |
334 | */ | |
335 | static inline uint32_t round_down(uint32_t n) | |
336 | { | |
337 | while (n & (n - 1)) | |
338 | n &= (n - 1); | |
339 | return n; | |
340 | } | |
341 | ||
342 | /* | |
343 | * Allocate room for a suitable hash table. | |
344 | */ | |
345 | static int init_hash_tables(struct dm_snapshot *s) | |
346 | { | |
347 | sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; | |
348 | ||
349 | /* | |
350 | * Calculate based on the size of the original volume or | |
351 | * the COW volume... | |
352 | */ | |
353 | cow_dev_size = get_dev_size(s->cow->bdev); | |
354 | origin_dev_size = get_dev_size(s->origin->bdev); | |
355 | max_buckets = calc_max_buckets(); | |
356 | ||
357 | hash_size = min(origin_dev_size, cow_dev_size) >> s->chunk_shift; | |
358 | hash_size = min(hash_size, max_buckets); | |
359 | ||
360 | /* Round it down to a power of 2 */ | |
361 | hash_size = round_down(hash_size); | |
362 | if (init_exception_table(&s->complete, hash_size)) | |
363 | return -ENOMEM; | |
364 | ||
365 | /* | |
366 | * Allocate hash table for in-flight exceptions | |
367 | * Make this smaller than the real hash table | |
368 | */ | |
369 | hash_size >>= 3; | |
370 | if (hash_size < 64) | |
371 | hash_size = 64; | |
372 | ||
373 | if (init_exception_table(&s->pending, hash_size)) { | |
374 | exit_exception_table(&s->complete, exception_cache); | |
375 | return -ENOMEM; | |
376 | } | |
377 | ||
378 | return 0; | |
379 | } | |
380 | ||
381 | /* | |
382 | * Round a number up to the nearest 'size' boundary. size must | |
383 | * be a power of 2. | |
384 | */ | |
385 | static inline ulong round_up(ulong n, ulong size) | |
386 | { | |
387 | size--; | |
388 | return (n + size) & ~size; | |
389 | } | |
390 | ||
2d38fe20 AK |
391 | static void read_snapshot_metadata(struct dm_snapshot *s) |
392 | { | |
2d38fe20 AK |
393 | if (s->store.read_metadata(&s->store)) { |
394 | down_write(&s->lock); | |
395 | s->valid = 0; | |
396 | up_write(&s->lock); | |
76df1c65 AK |
397 | |
398 | dm_table_event(s->table); | |
2d38fe20 | 399 | } |
2d38fe20 AK |
400 | } |
401 | ||
1da177e4 LT |
402 | /* |
403 | * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> | |
404 | */ | |
405 | static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
406 | { | |
407 | struct dm_snapshot *s; | |
408 | unsigned long chunk_size; | |
409 | int r = -EINVAL; | |
410 | char persistent; | |
411 | char *origin_path; | |
412 | char *cow_path; | |
413 | char *value; | |
414 | int blocksize; | |
415 | ||
416 | if (argc < 4) { | |
72d94861 | 417 | ti->error = "requires exactly 4 arguments"; |
1da177e4 LT |
418 | r = -EINVAL; |
419 | goto bad1; | |
420 | } | |
421 | ||
422 | origin_path = argv[0]; | |
423 | cow_path = argv[1]; | |
424 | persistent = toupper(*argv[2]); | |
425 | ||
426 | if (persistent != 'P' && persistent != 'N') { | |
427 | ti->error = "Persistent flag is not P or N"; | |
428 | r = -EINVAL; | |
429 | goto bad1; | |
430 | } | |
431 | ||
432 | chunk_size = simple_strtoul(argv[3], &value, 10); | |
433 | if (chunk_size == 0 || value == NULL) { | |
434 | ti->error = "Invalid chunk size"; | |
435 | r = -EINVAL; | |
436 | goto bad1; | |
437 | } | |
438 | ||
439 | s = kmalloc(sizeof(*s), GFP_KERNEL); | |
440 | if (s == NULL) { | |
441 | ti->error = "Cannot allocate snapshot context private " | |
442 | "structure"; | |
443 | r = -ENOMEM; | |
444 | goto bad1; | |
445 | } | |
446 | ||
447 | r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin); | |
448 | if (r) { | |
449 | ti->error = "Cannot get origin device"; | |
450 | goto bad2; | |
451 | } | |
452 | ||
453 | r = dm_get_device(ti, cow_path, 0, 0, | |
454 | FMODE_READ | FMODE_WRITE, &s->cow); | |
455 | if (r) { | |
456 | dm_put_device(ti, s->origin); | |
457 | ti->error = "Cannot get COW device"; | |
458 | goto bad2; | |
459 | } | |
460 | ||
461 | /* | |
462 | * Chunk size must be multiple of page size. Silently | |
463 | * round up if it's not. | |
464 | */ | |
465 | chunk_size = round_up(chunk_size, PAGE_SIZE >> 9); | |
466 | ||
467 | /* Validate the chunk size against the device block size */ | |
468 | blocksize = s->cow->bdev->bd_disk->queue->hardsect_size; | |
469 | if (chunk_size % (blocksize >> 9)) { | |
470 | ti->error = "Chunk size is not a multiple of device blocksize"; | |
471 | r = -EINVAL; | |
472 | goto bad3; | |
473 | } | |
474 | ||
475 | /* Check chunk_size is a power of 2 */ | |
476 | if (chunk_size & (chunk_size - 1)) { | |
477 | ti->error = "Chunk size is not a power of 2"; | |
478 | r = -EINVAL; | |
479 | goto bad3; | |
480 | } | |
481 | ||
482 | s->chunk_size = chunk_size; | |
483 | s->chunk_mask = chunk_size - 1; | |
484 | s->type = persistent; | |
485 | s->chunk_shift = ffs(chunk_size) - 1; | |
486 | ||
487 | s->valid = 1; | |
aa14edeb | 488 | s->active = 0; |
1da177e4 LT |
489 | s->last_percent = 0; |
490 | init_rwsem(&s->lock); | |
491 | s->table = ti->table; | |
492 | ||
493 | /* Allocate hash table for COW data */ | |
494 | if (init_hash_tables(s)) { | |
495 | ti->error = "Unable to allocate hash table space"; | |
496 | r = -ENOMEM; | |
497 | goto bad3; | |
498 | } | |
499 | ||
500 | /* | |
501 | * Check the persistent flag - done here because we need the iobuf | |
502 | * to check the LV header | |
503 | */ | |
504 | s->store.snap = s; | |
505 | ||
506 | if (persistent == 'P') | |
507 | r = dm_create_persistent(&s->store, chunk_size); | |
508 | else | |
509 | r = dm_create_transient(&s->store, s, blocksize); | |
510 | ||
511 | if (r) { | |
512 | ti->error = "Couldn't create exception store"; | |
513 | r = -EINVAL; | |
514 | goto bad4; | |
515 | } | |
516 | ||
517 | r = kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client); | |
518 | if (r) { | |
519 | ti->error = "Could not create kcopyd client"; | |
520 | goto bad5; | |
521 | } | |
522 | ||
aa14edeb AK |
523 | /* Metadata must only be loaded into one table at once */ |
524 | read_snapshot_metadata(s); | |
525 | ||
1da177e4 | 526 | /* Add snapshot to the list of snapshots for this origin */ |
aa14edeb | 527 | /* Exceptions aren't triggered till snapshot_resume() is called */ |
1da177e4 LT |
528 | if (register_snapshot(s)) { |
529 | r = -EINVAL; | |
530 | ti->error = "Cannot register snapshot origin"; | |
531 | goto bad6; | |
532 | } | |
533 | ||
534 | ti->private = s; | |
c51c2752 | 535 | ti->split_io = s->chunk_size; |
1da177e4 LT |
536 | |
537 | return 0; | |
538 | ||
539 | bad6: | |
540 | kcopyd_client_destroy(s->kcopyd_client); | |
541 | ||
542 | bad5: | |
543 | s->store.destroy(&s->store); | |
544 | ||
545 | bad4: | |
546 | exit_exception_table(&s->pending, pending_cache); | |
547 | exit_exception_table(&s->complete, exception_cache); | |
548 | ||
549 | bad3: | |
550 | dm_put_device(ti, s->cow); | |
551 | dm_put_device(ti, s->origin); | |
552 | ||
553 | bad2: | |
554 | kfree(s); | |
555 | ||
556 | bad1: | |
557 | return r; | |
558 | } | |
559 | ||
560 | static void snapshot_dtr(struct dm_target *ti) | |
561 | { | |
562 | struct dm_snapshot *s = (struct dm_snapshot *) ti->private; | |
563 | ||
138728dc AK |
564 | /* Prevent further origin writes from using this snapshot. */ |
565 | /* After this returns there can be no new kcopyd jobs. */ | |
1da177e4 LT |
566 | unregister_snapshot(s); |
567 | ||
138728dc AK |
568 | kcopyd_client_destroy(s->kcopyd_client); |
569 | ||
1da177e4 LT |
570 | exit_exception_table(&s->pending, pending_cache); |
571 | exit_exception_table(&s->complete, exception_cache); | |
572 | ||
573 | /* Deallocate memory used */ | |
574 | s->store.destroy(&s->store); | |
575 | ||
576 | dm_put_device(ti, s->origin); | |
577 | dm_put_device(ti, s->cow); | |
138728dc | 578 | |
1da177e4 LT |
579 | kfree(s); |
580 | } | |
581 | ||
582 | /* | |
583 | * Flush a list of buffers. | |
584 | */ | |
585 | static void flush_bios(struct bio *bio) | |
586 | { | |
587 | struct bio *n; | |
588 | ||
589 | while (bio) { | |
590 | n = bio->bi_next; | |
591 | bio->bi_next = NULL; | |
592 | generic_make_request(bio); | |
593 | bio = n; | |
594 | } | |
595 | } | |
596 | ||
597 | /* | |
598 | * Error a list of buffers. | |
599 | */ | |
600 | static void error_bios(struct bio *bio) | |
601 | { | |
602 | struct bio *n; | |
603 | ||
604 | while (bio) { | |
605 | n = bio->bi_next; | |
606 | bio->bi_next = NULL; | |
607 | bio_io_error(bio, bio->bi_size); | |
608 | bio = n; | |
609 | } | |
610 | } | |
611 | ||
76df1c65 AK |
612 | static inline void error_snapshot_bios(struct pending_exception *pe) |
613 | { | |
614 | error_bios(bio_list_get(&pe->snapshot_bios)); | |
615 | } | |
616 | ||
1da177e4 LT |
617 | static struct bio *__flush_bios(struct pending_exception *pe) |
618 | { | |
b4b610f6 AK |
619 | /* |
620 | * If this pe is involved in a write to the origin and | |
621 | * it is the last sibling to complete then release | |
622 | * the bios for the original write to the origin. | |
1da177e4 | 623 | */ |
b4b610f6 AK |
624 | |
625 | if (pe->primary_pe && | |
626 | atomic_dec_and_test(&pe->primary_pe->sibling_count)) | |
627 | return bio_list_get(&pe->primary_pe->origin_bios); | |
1da177e4 LT |
628 | |
629 | return NULL; | |
630 | } | |
631 | ||
76df1c65 AK |
632 | static void __invalidate_snapshot(struct dm_snapshot *s, |
633 | struct pending_exception *pe, int err) | |
634 | { | |
635 | if (!s->valid) | |
636 | return; | |
637 | ||
638 | if (err == -EIO) | |
639 | DMERR("Invalidating snapshot: Error reading/writing."); | |
640 | else if (err == -ENOMEM) | |
641 | DMERR("Invalidating snapshot: Unable to allocate exception."); | |
642 | ||
643 | if (pe) | |
644 | remove_exception(&pe->e); | |
645 | ||
646 | if (s->store.drop_snapshot) | |
647 | s->store.drop_snapshot(&s->store); | |
648 | ||
649 | s->valid = 0; | |
650 | ||
651 | dm_table_event(s->table); | |
652 | } | |
653 | ||
1da177e4 LT |
654 | static void pending_complete(struct pending_exception *pe, int success) |
655 | { | |
656 | struct exception *e; | |
b4b610f6 | 657 | struct pending_exception *primary_pe; |
1da177e4 LT |
658 | struct dm_snapshot *s = pe->snap; |
659 | struct bio *flush = NULL; | |
660 | ||
76df1c65 AK |
661 | if (!success) { |
662 | /* Read/write error - snapshot is unusable */ | |
1da177e4 | 663 | down_write(&s->lock); |
76df1c65 | 664 | __invalidate_snapshot(s, pe, -EIO); |
1da177e4 | 665 | flush = __flush_bios(pe); |
1da177e4 LT |
666 | up_write(&s->lock); |
667 | ||
76df1c65 AK |
668 | error_snapshot_bios(pe); |
669 | goto out; | |
670 | } | |
671 | ||
672 | e = alloc_exception(); | |
673 | if (!e) { | |
1da177e4 | 674 | down_write(&s->lock); |
76df1c65 | 675 | __invalidate_snapshot(s, pe, -ENOMEM); |
1da177e4 LT |
676 | flush = __flush_bios(pe); |
677 | up_write(&s->lock); | |
678 | ||
76df1c65 AK |
679 | error_snapshot_bios(pe); |
680 | goto out; | |
681 | } | |
682 | *e = pe->e; | |
1da177e4 | 683 | |
76df1c65 AK |
684 | /* |
685 | * Add a proper exception, and remove the | |
686 | * in-flight exception from the list. | |
687 | */ | |
688 | down_write(&s->lock); | |
689 | if (!s->valid) { | |
690 | flush = __flush_bios(pe); | |
691 | up_write(&s->lock); | |
692 | ||
693 | free_exception(e); | |
694 | ||
695 | error_snapshot_bios(pe); | |
696 | goto out; | |
1da177e4 LT |
697 | } |
698 | ||
76df1c65 AK |
699 | insert_exception(&s->complete, e); |
700 | remove_exception(&pe->e); | |
701 | flush = __flush_bios(pe); | |
702 | ||
703 | up_write(&s->lock); | |
704 | ||
705 | /* Submit any pending write bios */ | |
706 | flush_bios(bio_list_get(&pe->snapshot_bios)); | |
707 | ||
1da177e4 | 708 | out: |
b4b610f6 AK |
709 | primary_pe = pe->primary_pe; |
710 | ||
711 | /* | |
712 | * Free the pe if it's not linked to an origin write or if | |
713 | * it's not itself a primary pe. | |
714 | */ | |
715 | if (!primary_pe || primary_pe != pe) | |
716 | free_pending_exception(pe); | |
717 | ||
718 | /* | |
719 | * Free the primary pe if nothing references it. | |
720 | */ | |
721 | if (primary_pe && !atomic_read(&primary_pe->sibling_count)) | |
722 | free_pending_exception(primary_pe); | |
1da177e4 LT |
723 | |
724 | if (flush) | |
725 | flush_bios(flush); | |
726 | } | |
727 | ||
728 | static void commit_callback(void *context, int success) | |
729 | { | |
730 | struct pending_exception *pe = (struct pending_exception *) context; | |
731 | pending_complete(pe, success); | |
732 | } | |
733 | ||
734 | /* | |
735 | * Called when the copy I/O has finished. kcopyd actually runs | |
736 | * this code so don't block. | |
737 | */ | |
738 | static void copy_callback(int read_err, unsigned int write_err, void *context) | |
739 | { | |
740 | struct pending_exception *pe = (struct pending_exception *) context; | |
741 | struct dm_snapshot *s = pe->snap; | |
742 | ||
743 | if (read_err || write_err) | |
744 | pending_complete(pe, 0); | |
745 | ||
746 | else | |
747 | /* Update the metadata if we are persistent */ | |
748 | s->store.commit_exception(&s->store, &pe->e, commit_callback, | |
749 | pe); | |
750 | } | |
751 | ||
752 | /* | |
753 | * Dispatches the copy operation to kcopyd. | |
754 | */ | |
858119e1 | 755 | static void start_copy(struct pending_exception *pe) |
1da177e4 LT |
756 | { |
757 | struct dm_snapshot *s = pe->snap; | |
758 | struct io_region src, dest; | |
759 | struct block_device *bdev = s->origin->bdev; | |
760 | sector_t dev_size; | |
761 | ||
762 | dev_size = get_dev_size(bdev); | |
763 | ||
764 | src.bdev = bdev; | |
765 | src.sector = chunk_to_sector(s, pe->e.old_chunk); | |
766 | src.count = min(s->chunk_size, dev_size - src.sector); | |
767 | ||
768 | dest.bdev = s->cow->bdev; | |
769 | dest.sector = chunk_to_sector(s, pe->e.new_chunk); | |
770 | dest.count = src.count; | |
771 | ||
772 | /* Hand over to kcopyd */ | |
773 | kcopyd_copy(s->kcopyd_client, | |
774 | &src, 1, &dest, 0, copy_callback, pe); | |
775 | } | |
776 | ||
777 | /* | |
778 | * Looks to see if this snapshot already has a pending exception | |
779 | * for this chunk, otherwise it allocates a new one and inserts | |
780 | * it into the pending table. | |
781 | * | |
782 | * NOTE: a write lock must be held on snap->lock before calling | |
783 | * this. | |
784 | */ | |
785 | static struct pending_exception * | |
786 | __find_pending_exception(struct dm_snapshot *s, struct bio *bio) | |
787 | { | |
788 | struct exception *e; | |
789 | struct pending_exception *pe; | |
790 | chunk_t chunk = sector_to_chunk(s, bio->bi_sector); | |
791 | ||
792 | /* | |
793 | * Is there a pending exception for this already ? | |
794 | */ | |
795 | e = lookup_exception(&s->pending, chunk); | |
796 | if (e) { | |
797 | /* cast the exception to a pending exception */ | |
798 | pe = container_of(e, struct pending_exception, e); | |
76df1c65 AK |
799 | goto out; |
800 | } | |
1da177e4 | 801 | |
76df1c65 AK |
802 | /* |
803 | * Create a new pending exception, we don't want | |
804 | * to hold the lock while we do this. | |
805 | */ | |
806 | up_write(&s->lock); | |
807 | pe = alloc_pending_exception(); | |
808 | down_write(&s->lock); | |
1da177e4 | 809 | |
76df1c65 AK |
810 | if (!s->valid) { |
811 | free_pending_exception(pe); | |
812 | return NULL; | |
813 | } | |
1da177e4 | 814 | |
76df1c65 AK |
815 | e = lookup_exception(&s->pending, chunk); |
816 | if (e) { | |
817 | free_pending_exception(pe); | |
818 | pe = container_of(e, struct pending_exception, e); | |
819 | goto out; | |
1da177e4 LT |
820 | } |
821 | ||
76df1c65 AK |
822 | pe->e.old_chunk = chunk; |
823 | bio_list_init(&pe->origin_bios); | |
824 | bio_list_init(&pe->snapshot_bios); | |
825 | pe->primary_pe = NULL; | |
826 | atomic_set(&pe->sibling_count, 1); | |
827 | pe->snap = s; | |
828 | pe->started = 0; | |
829 | ||
830 | if (s->store.prepare_exception(&s->store, &pe->e)) { | |
831 | free_pending_exception(pe); | |
832 | return NULL; | |
833 | } | |
834 | ||
835 | insert_exception(&s->pending, &pe->e); | |
836 | ||
837 | out: | |
1da177e4 LT |
838 | return pe; |
839 | } | |
840 | ||
841 | static inline void remap_exception(struct dm_snapshot *s, struct exception *e, | |
842 | struct bio *bio) | |
843 | { | |
844 | bio->bi_bdev = s->cow->bdev; | |
845 | bio->bi_sector = chunk_to_sector(s, e->new_chunk) + | |
846 | (bio->bi_sector & s->chunk_mask); | |
847 | } | |
848 | ||
849 | static int snapshot_map(struct dm_target *ti, struct bio *bio, | |
850 | union map_info *map_context) | |
851 | { | |
852 | struct exception *e; | |
853 | struct dm_snapshot *s = (struct dm_snapshot *) ti->private; | |
76df1c65 | 854 | int copy_needed = 0; |
1da177e4 LT |
855 | int r = 1; |
856 | chunk_t chunk; | |
76df1c65 | 857 | struct pending_exception *pe = NULL; |
1da177e4 LT |
858 | |
859 | chunk = sector_to_chunk(s, bio->bi_sector); | |
860 | ||
861 | /* Full snapshots are not usable */ | |
76df1c65 | 862 | /* To get here the table must be live so s->active is always set. */ |
1da177e4 | 863 | if (!s->valid) |
f6a80ea8 | 864 | return -EIO; |
1da177e4 | 865 | |
4aac0a63 AK |
866 | if (unlikely(bio_barrier(bio))) |
867 | return -EOPNOTSUPP; | |
868 | ||
1da177e4 LT |
869 | /* |
870 | * Write to snapshot - higher level takes care of RW/RO | |
871 | * flags so we should only get this if we are | |
872 | * writeable. | |
873 | */ | |
874 | if (bio_rw(bio) == WRITE) { | |
875 | ||
876 | /* FIXME: should only take write lock if we need | |
877 | * to copy an exception */ | |
878 | down_write(&s->lock); | |
879 | ||
76df1c65 AK |
880 | if (!s->valid) { |
881 | r = -EIO; | |
882 | goto out_unlock; | |
883 | } | |
884 | ||
1da177e4 LT |
885 | /* If the block is already remapped - use that, else remap it */ |
886 | e = lookup_exception(&s->complete, chunk); | |
887 | if (e) { | |
888 | remap_exception(s, e, bio); | |
76df1c65 AK |
889 | goto out_unlock; |
890 | } | |
891 | ||
892 | pe = __find_pending_exception(s, bio); | |
893 | if (!pe) { | |
894 | __invalidate_snapshot(s, pe, -ENOMEM); | |
895 | r = -EIO; | |
896 | goto out_unlock; | |
1da177e4 LT |
897 | } |
898 | ||
76df1c65 AK |
899 | remap_exception(s, &pe->e, bio); |
900 | bio_list_add(&pe->snapshot_bios, bio); | |
901 | ||
902 | if (!pe->started) { | |
903 | /* this is protected by snap->lock */ | |
904 | pe->started = 1; | |
905 | copy_needed = 1; | |
906 | } | |
907 | ||
908 | r = 0; | |
909 | ||
910 | out_unlock: | |
911 | up_write(&s->lock); | |
912 | ||
913 | if (copy_needed) | |
914 | start_copy(pe); | |
1da177e4 LT |
915 | } else { |
916 | /* | |
917 | * FIXME: this read path scares me because we | |
918 | * always use the origin when we have a pending | |
919 | * exception. However I can't think of a | |
920 | * situation where this is wrong - ejt. | |
921 | */ | |
922 | ||
923 | /* Do reads */ | |
924 | down_read(&s->lock); | |
925 | ||
76df1c65 AK |
926 | if (!s->valid) { |
927 | up_read(&s->lock); | |
928 | return -EIO; | |
929 | } | |
930 | ||
1da177e4 LT |
931 | /* See if it it has been remapped */ |
932 | e = lookup_exception(&s->complete, chunk); | |
933 | if (e) | |
934 | remap_exception(s, e, bio); | |
935 | else | |
936 | bio->bi_bdev = s->origin->bdev; | |
937 | ||
938 | up_read(&s->lock); | |
939 | } | |
940 | ||
941 | return r; | |
942 | } | |
943 | ||
944 | static void snapshot_resume(struct dm_target *ti) | |
945 | { | |
946 | struct dm_snapshot *s = (struct dm_snapshot *) ti->private; | |
947 | ||
aa14edeb AK |
948 | down_write(&s->lock); |
949 | s->active = 1; | |
950 | up_write(&s->lock); | |
1da177e4 LT |
951 | } |
952 | ||
953 | static int snapshot_status(struct dm_target *ti, status_type_t type, | |
954 | char *result, unsigned int maxlen) | |
955 | { | |
956 | struct dm_snapshot *snap = (struct dm_snapshot *) ti->private; | |
957 | ||
958 | switch (type) { | |
959 | case STATUSTYPE_INFO: | |
960 | if (!snap->valid) | |
961 | snprintf(result, maxlen, "Invalid"); | |
962 | else { | |
963 | if (snap->store.fraction_full) { | |
964 | sector_t numerator, denominator; | |
965 | snap->store.fraction_full(&snap->store, | |
966 | &numerator, | |
967 | &denominator); | |
4ee218cd AM |
968 | snprintf(result, maxlen, "%llu/%llu", |
969 | (unsigned long long)numerator, | |
970 | (unsigned long long)denominator); | |
1da177e4 LT |
971 | } |
972 | else | |
973 | snprintf(result, maxlen, "Unknown"); | |
974 | } | |
975 | break; | |
976 | ||
977 | case STATUSTYPE_TABLE: | |
978 | /* | |
979 | * kdevname returns a static pointer so we need | |
980 | * to make private copies if the output is to | |
981 | * make sense. | |
982 | */ | |
4ee218cd | 983 | snprintf(result, maxlen, "%s %s %c %llu", |
1da177e4 | 984 | snap->origin->name, snap->cow->name, |
4ee218cd AM |
985 | snap->type, |
986 | (unsigned long long)snap->chunk_size); | |
1da177e4 LT |
987 | break; |
988 | } | |
989 | ||
990 | return 0; | |
991 | } | |
992 | ||
993 | /*----------------------------------------------------------------- | |
994 | * Origin methods | |
995 | *---------------------------------------------------------------*/ | |
1da177e4 LT |
996 | static int __origin_write(struct list_head *snapshots, struct bio *bio) |
997 | { | |
b4b610f6 | 998 | int r = 1, first = 0; |
1da177e4 LT |
999 | struct dm_snapshot *snap; |
1000 | struct exception *e; | |
b4b610f6 | 1001 | struct pending_exception *pe, *next_pe, *primary_pe = NULL; |
1da177e4 | 1002 | chunk_t chunk; |
eccf0817 | 1003 | LIST_HEAD(pe_queue); |
1da177e4 LT |
1004 | |
1005 | /* Do all the snapshots on this origin */ | |
1006 | list_for_each_entry (snap, snapshots, list) { | |
1007 | ||
76df1c65 AK |
1008 | down_write(&snap->lock); |
1009 | ||
aa14edeb AK |
1010 | /* Only deal with valid and active snapshots */ |
1011 | if (!snap->valid || !snap->active) | |
76df1c65 | 1012 | goto next_snapshot; |
1da177e4 | 1013 | |
d5e404c1 AK |
1014 | /* Nothing to do if writing beyond end of snapshot */ |
1015 | if (bio->bi_sector >= dm_table_get_size(snap->table)) | |
76df1c65 | 1016 | goto next_snapshot; |
1da177e4 LT |
1017 | |
1018 | /* | |
1019 | * Remember, different snapshots can have | |
1020 | * different chunk sizes. | |
1021 | */ | |
1022 | chunk = sector_to_chunk(snap, bio->bi_sector); | |
1023 | ||
1024 | /* | |
1025 | * Check exception table to see if block | |
1026 | * is already remapped in this snapshot | |
1027 | * and trigger an exception if not. | |
b4b610f6 AK |
1028 | * |
1029 | * sibling_count is initialised to 1 so pending_complete() | |
1030 | * won't destroy the primary_pe while we're inside this loop. | |
1da177e4 LT |
1031 | */ |
1032 | e = lookup_exception(&snap->complete, chunk); | |
76df1c65 AK |
1033 | if (e) |
1034 | goto next_snapshot; | |
1035 | ||
1036 | pe = __find_pending_exception(snap, bio); | |
1037 | if (!pe) { | |
1038 | __invalidate_snapshot(snap, pe, ENOMEM); | |
1039 | goto next_snapshot; | |
1040 | } | |
1041 | ||
1042 | if (!primary_pe) { | |
1043 | /* | |
1044 | * Either every pe here has same | |
1045 | * primary_pe or none has one yet. | |
1046 | */ | |
1047 | if (pe->primary_pe) | |
1048 | primary_pe = pe->primary_pe; | |
1049 | else { | |
1050 | primary_pe = pe; | |
1051 | first = 1; | |
1da177e4 | 1052 | } |
76df1c65 AK |
1053 | |
1054 | bio_list_add(&primary_pe->origin_bios, bio); | |
1055 | ||
1056 | r = 0; | |
1057 | } | |
1058 | ||
1059 | if (!pe->primary_pe) { | |
1060 | atomic_inc(&primary_pe->sibling_count); | |
1061 | pe->primary_pe = primary_pe; | |
1062 | } | |
1063 | ||
1064 | if (!pe->started) { | |
1065 | pe->started = 1; | |
1066 | list_add_tail(&pe->list, &pe_queue); | |
1da177e4 LT |
1067 | } |
1068 | ||
76df1c65 | 1069 | next_snapshot: |
1da177e4 LT |
1070 | up_write(&snap->lock); |
1071 | } | |
1072 | ||
b4b610f6 AK |
1073 | if (!primary_pe) |
1074 | goto out; | |
1075 | ||
1076 | /* | |
1077 | * If this is the first time we're processing this chunk and | |
1078 | * sibling_count is now 1 it means all the pending exceptions | |
1079 | * got completed while we were in the loop above, so it falls to | |
1080 | * us here to remove the primary_pe and submit any origin_bios. | |
1081 | */ | |
1082 | ||
1083 | if (first && atomic_dec_and_test(&primary_pe->sibling_count)) { | |
1084 | flush_bios(bio_list_get(&primary_pe->origin_bios)); | |
1085 | free_pending_exception(primary_pe); | |
1086 | /* If we got here, pe_queue is necessarily empty. */ | |
1087 | goto out; | |
1088 | } | |
1089 | ||
1da177e4 LT |
1090 | /* |
1091 | * Now that we have a complete pe list we can start the copying. | |
1092 | */ | |
eccf0817 AK |
1093 | list_for_each_entry_safe(pe, next_pe, &pe_queue, list) |
1094 | start_copy(pe); | |
1da177e4 | 1095 | |
b4b610f6 | 1096 | out: |
1da177e4 LT |
1097 | return r; |
1098 | } | |
1099 | ||
1100 | /* | |
1101 | * Called on a write from the origin driver. | |
1102 | */ | |
1103 | static int do_origin(struct dm_dev *origin, struct bio *bio) | |
1104 | { | |
1105 | struct origin *o; | |
1106 | int r = 1; | |
1107 | ||
1108 | down_read(&_origins_lock); | |
1109 | o = __lookup_origin(origin->bdev); | |
1110 | if (o) | |
1111 | r = __origin_write(&o->snapshots, bio); | |
1112 | up_read(&_origins_lock); | |
1113 | ||
1114 | return r; | |
1115 | } | |
1116 | ||
1117 | /* | |
1118 | * Origin: maps a linear range of a device, with hooks for snapshotting. | |
1119 | */ | |
1120 | ||
1121 | /* | |
1122 | * Construct an origin mapping: <dev_path> | |
1123 | * The context for an origin is merely a 'struct dm_dev *' | |
1124 | * pointing to the real device. | |
1125 | */ | |
1126 | static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
1127 | { | |
1128 | int r; | |
1129 | struct dm_dev *dev; | |
1130 | ||
1131 | if (argc != 1) { | |
72d94861 | 1132 | ti->error = "origin: incorrect number of arguments"; |
1da177e4 LT |
1133 | return -EINVAL; |
1134 | } | |
1135 | ||
1136 | r = dm_get_device(ti, argv[0], 0, ti->len, | |
1137 | dm_table_get_mode(ti->table), &dev); | |
1138 | if (r) { | |
1139 | ti->error = "Cannot get target device"; | |
1140 | return r; | |
1141 | } | |
1142 | ||
1143 | ti->private = dev; | |
1144 | return 0; | |
1145 | } | |
1146 | ||
1147 | static void origin_dtr(struct dm_target *ti) | |
1148 | { | |
1149 | struct dm_dev *dev = (struct dm_dev *) ti->private; | |
1150 | dm_put_device(ti, dev); | |
1151 | } | |
1152 | ||
1153 | static int origin_map(struct dm_target *ti, struct bio *bio, | |
1154 | union map_info *map_context) | |
1155 | { | |
1156 | struct dm_dev *dev = (struct dm_dev *) ti->private; | |
1157 | bio->bi_bdev = dev->bdev; | |
1158 | ||
4aac0a63 AK |
1159 | if (unlikely(bio_barrier(bio))) |
1160 | return -EOPNOTSUPP; | |
1161 | ||
1da177e4 LT |
1162 | /* Only tell snapshots if this is a write */ |
1163 | return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : 1; | |
1164 | } | |
1165 | ||
1166 | #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) | |
1167 | ||
1168 | /* | |
1169 | * Set the target "split_io" field to the minimum of all the snapshots' | |
1170 | * chunk sizes. | |
1171 | */ | |
1172 | static void origin_resume(struct dm_target *ti) | |
1173 | { | |
1174 | struct dm_dev *dev = (struct dm_dev *) ti->private; | |
1175 | struct dm_snapshot *snap; | |
1176 | struct origin *o; | |
1177 | chunk_t chunk_size = 0; | |
1178 | ||
1179 | down_read(&_origins_lock); | |
1180 | o = __lookup_origin(dev->bdev); | |
1181 | if (o) | |
1182 | list_for_each_entry (snap, &o->snapshots, list) | |
1183 | chunk_size = min_not_zero(chunk_size, snap->chunk_size); | |
1184 | up_read(&_origins_lock); | |
1185 | ||
1186 | ti->split_io = chunk_size; | |
1187 | } | |
1188 | ||
1189 | static int origin_status(struct dm_target *ti, status_type_t type, char *result, | |
1190 | unsigned int maxlen) | |
1191 | { | |
1192 | struct dm_dev *dev = (struct dm_dev *) ti->private; | |
1193 | ||
1194 | switch (type) { | |
1195 | case STATUSTYPE_INFO: | |
1196 | result[0] = '\0'; | |
1197 | break; | |
1198 | ||
1199 | case STATUSTYPE_TABLE: | |
1200 | snprintf(result, maxlen, "%s", dev->name); | |
1201 | break; | |
1202 | } | |
1203 | ||
1204 | return 0; | |
1205 | } | |
1206 | ||
1207 | static struct target_type origin_target = { | |
1208 | .name = "snapshot-origin", | |
c51c2752 | 1209 | .version = {1, 4, 0}, |
1da177e4 LT |
1210 | .module = THIS_MODULE, |
1211 | .ctr = origin_ctr, | |
1212 | .dtr = origin_dtr, | |
1213 | .map = origin_map, | |
1214 | .resume = origin_resume, | |
1215 | .status = origin_status, | |
1216 | }; | |
1217 | ||
1218 | static struct target_type snapshot_target = { | |
1219 | .name = "snapshot", | |
c51c2752 | 1220 | .version = {1, 4, 0}, |
1da177e4 LT |
1221 | .module = THIS_MODULE, |
1222 | .ctr = snapshot_ctr, | |
1223 | .dtr = snapshot_dtr, | |
1224 | .map = snapshot_map, | |
1225 | .resume = snapshot_resume, | |
1226 | .status = snapshot_status, | |
1227 | }; | |
1228 | ||
1229 | static int __init dm_snapshot_init(void) | |
1230 | { | |
1231 | int r; | |
1232 | ||
1233 | r = dm_register_target(&snapshot_target); | |
1234 | if (r) { | |
1235 | DMERR("snapshot target register failed %d", r); | |
1236 | return r; | |
1237 | } | |
1238 | ||
1239 | r = dm_register_target(&origin_target); | |
1240 | if (r < 0) { | |
72d94861 | 1241 | DMERR("Origin target register failed %d", r); |
1da177e4 LT |
1242 | goto bad1; |
1243 | } | |
1244 | ||
1245 | r = init_origin_hash(); | |
1246 | if (r) { | |
1247 | DMERR("init_origin_hash failed."); | |
1248 | goto bad2; | |
1249 | } | |
1250 | ||
1251 | exception_cache = kmem_cache_create("dm-snapshot-ex", | |
1252 | sizeof(struct exception), | |
1253 | __alignof__(struct exception), | |
1254 | 0, NULL, NULL); | |
1255 | if (!exception_cache) { | |
1256 | DMERR("Couldn't create exception cache."); | |
1257 | r = -ENOMEM; | |
1258 | goto bad3; | |
1259 | } | |
1260 | ||
1261 | pending_cache = | |
1262 | kmem_cache_create("dm-snapshot-in", | |
1263 | sizeof(struct pending_exception), | |
1264 | __alignof__(struct pending_exception), | |
1265 | 0, NULL, NULL); | |
1266 | if (!pending_cache) { | |
1267 | DMERR("Couldn't create pending cache."); | |
1268 | r = -ENOMEM; | |
1269 | goto bad4; | |
1270 | } | |
1271 | ||
93d2341c | 1272 | pending_pool = mempool_create_slab_pool(128, pending_cache); |
1da177e4 LT |
1273 | if (!pending_pool) { |
1274 | DMERR("Couldn't create pending pool."); | |
1275 | r = -ENOMEM; | |
1276 | goto bad5; | |
1277 | } | |
1278 | ||
1279 | return 0; | |
1280 | ||
1281 | bad5: | |
1282 | kmem_cache_destroy(pending_cache); | |
1283 | bad4: | |
1284 | kmem_cache_destroy(exception_cache); | |
1285 | bad3: | |
1286 | exit_origin_hash(); | |
1287 | bad2: | |
1288 | dm_unregister_target(&origin_target); | |
1289 | bad1: | |
1290 | dm_unregister_target(&snapshot_target); | |
1291 | return r; | |
1292 | } | |
1293 | ||
1294 | static void __exit dm_snapshot_exit(void) | |
1295 | { | |
1296 | int r; | |
1297 | ||
1298 | r = dm_unregister_target(&snapshot_target); | |
1299 | if (r) | |
1300 | DMERR("snapshot unregister failed %d", r); | |
1301 | ||
1302 | r = dm_unregister_target(&origin_target); | |
1303 | if (r) | |
1304 | DMERR("origin unregister failed %d", r); | |
1305 | ||
1306 | exit_origin_hash(); | |
1307 | mempool_destroy(pending_pool); | |
1308 | kmem_cache_destroy(pending_cache); | |
1309 | kmem_cache_destroy(exception_cache); | |
1310 | } | |
1311 | ||
1312 | /* Module hooks */ | |
1313 | module_init(dm_snapshot_init); | |
1314 | module_exit(dm_snapshot_exit); | |
1315 | ||
1316 | MODULE_DESCRIPTION(DM_NAME " snapshot target"); | |
1317 | MODULE_AUTHOR("Joe Thornber"); | |
1318 | MODULE_LICENSE("GPL"); |