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