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 | ||
c642f9e0 | 42 | static struct workqueue_struct *ksnapd; |
c4028958 | 43 | static void flush_queued_bios(struct work_struct *work); |
ca3a931f | 44 | |
1da177e4 LT |
45 | struct pending_exception { |
46 | struct exception e; | |
47 | ||
48 | /* | |
49 | * Origin buffers waiting for this to complete are held | |
50 | * in a bio list | |
51 | */ | |
52 | struct bio_list origin_bios; | |
53 | struct bio_list snapshot_bios; | |
54 | ||
eccf0817 AK |
55 | /* |
56 | * Short-term queue of pending exceptions prior to submission. | |
57 | */ | |
58 | struct list_head list; | |
59 | ||
1da177e4 | 60 | /* |
b4b610f6 | 61 | * The primary pending_exception is the one that holds |
4b832e8d | 62 | * the ref_count and the list of origin_bios for a |
b4b610f6 AK |
63 | * group of pending_exceptions. It is always last to get freed. |
64 | * These fields get set up when writing to the origin. | |
1da177e4 | 65 | */ |
b4b610f6 AK |
66 | struct pending_exception *primary_pe; |
67 | ||
68 | /* | |
69 | * Number of pending_exceptions processing this chunk. | |
70 | * When this drops to zero we must complete the origin bios. | |
71 | * If incrementing or decrementing this, hold pe->snap->lock for | |
72 | * the sibling concerned and not pe->primary_pe->snap->lock unless | |
73 | * they are the same. | |
74 | */ | |
4b832e8d | 75 | atomic_t ref_count; |
1da177e4 LT |
76 | |
77 | /* Pointer back to snapshot context */ | |
78 | struct dm_snapshot *snap; | |
79 | ||
80 | /* | |
81 | * 1 indicates the exception has already been sent to | |
82 | * kcopyd. | |
83 | */ | |
84 | int started; | |
85 | }; | |
86 | ||
87 | /* | |
88 | * Hash table mapping origin volumes to lists of snapshots and | |
89 | * a lock to protect it | |
90 | */ | |
e18b890b CL |
91 | static struct kmem_cache *exception_cache; |
92 | static struct kmem_cache *pending_cache; | |
1da177e4 LT |
93 | static mempool_t *pending_pool; |
94 | ||
95 | /* | |
96 | * One of these per registered origin, held in the snapshot_origins hash | |
97 | */ | |
98 | struct origin { | |
99 | /* The origin device */ | |
100 | struct block_device *bdev; | |
101 | ||
102 | struct list_head hash_list; | |
103 | ||
104 | /* List of snapshots for this origin */ | |
105 | struct list_head snapshots; | |
106 | }; | |
107 | ||
108 | /* | |
109 | * Size of the hash table for origin volumes. If we make this | |
110 | * the size of the minors list then it should be nearly perfect | |
111 | */ | |
112 | #define ORIGIN_HASH_SIZE 256 | |
113 | #define ORIGIN_MASK 0xFF | |
114 | static struct list_head *_origins; | |
115 | static struct rw_semaphore _origins_lock; | |
116 | ||
117 | static int init_origin_hash(void) | |
118 | { | |
119 | int i; | |
120 | ||
121 | _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), | |
122 | GFP_KERNEL); | |
123 | if (!_origins) { | |
72d94861 | 124 | DMERR("unable to allocate memory"); |
1da177e4 LT |
125 | return -ENOMEM; |
126 | } | |
127 | ||
128 | for (i = 0; i < ORIGIN_HASH_SIZE; i++) | |
129 | INIT_LIST_HEAD(_origins + i); | |
130 | init_rwsem(&_origins_lock); | |
131 | ||
132 | return 0; | |
133 | } | |
134 | ||
135 | static void exit_origin_hash(void) | |
136 | { | |
137 | kfree(_origins); | |
138 | } | |
139 | ||
140 | static inline unsigned int origin_hash(struct block_device *bdev) | |
141 | { | |
142 | return bdev->bd_dev & ORIGIN_MASK; | |
143 | } | |
144 | ||
145 | static struct origin *__lookup_origin(struct block_device *origin) | |
146 | { | |
147 | struct list_head *ol; | |
148 | struct origin *o; | |
149 | ||
150 | ol = &_origins[origin_hash(origin)]; | |
151 | list_for_each_entry (o, ol, hash_list) | |
152 | if (bdev_equal(o->bdev, origin)) | |
153 | return o; | |
154 | ||
155 | return NULL; | |
156 | } | |
157 | ||
158 | static void __insert_origin(struct origin *o) | |
159 | { | |
160 | struct list_head *sl = &_origins[origin_hash(o->bdev)]; | |
161 | list_add_tail(&o->hash_list, sl); | |
162 | } | |
163 | ||
164 | /* | |
165 | * Make a note of the snapshot and its origin so we can look it | |
166 | * up when the origin has a write on it. | |
167 | */ | |
168 | static int register_snapshot(struct dm_snapshot *snap) | |
169 | { | |
170 | struct origin *o; | |
171 | struct block_device *bdev = snap->origin->bdev; | |
172 | ||
173 | down_write(&_origins_lock); | |
174 | o = __lookup_origin(bdev); | |
175 | ||
176 | if (!o) { | |
177 | /* New origin */ | |
178 | o = kmalloc(sizeof(*o), GFP_KERNEL); | |
179 | if (!o) { | |
180 | up_write(&_origins_lock); | |
181 | return -ENOMEM; | |
182 | } | |
183 | ||
184 | /* Initialise the struct */ | |
185 | INIT_LIST_HEAD(&o->snapshots); | |
186 | o->bdev = bdev; | |
187 | ||
188 | __insert_origin(o); | |
189 | } | |
190 | ||
191 | list_add_tail(&snap->list, &o->snapshots); | |
192 | ||
193 | up_write(&_origins_lock); | |
194 | return 0; | |
195 | } | |
196 | ||
197 | static void unregister_snapshot(struct dm_snapshot *s) | |
198 | { | |
199 | struct origin *o; | |
200 | ||
201 | down_write(&_origins_lock); | |
202 | o = __lookup_origin(s->origin->bdev); | |
203 | ||
204 | list_del(&s->list); | |
205 | if (list_empty(&o->snapshots)) { | |
206 | list_del(&o->hash_list); | |
207 | kfree(o); | |
208 | } | |
209 | ||
210 | up_write(&_origins_lock); | |
211 | } | |
212 | ||
213 | /* | |
214 | * Implementation of the exception hash tables. | |
215 | */ | |
216 | static int init_exception_table(struct exception_table *et, uint32_t size) | |
217 | { | |
218 | unsigned int i; | |
219 | ||
220 | et->hash_mask = size - 1; | |
221 | et->table = dm_vcalloc(size, sizeof(struct list_head)); | |
222 | if (!et->table) | |
223 | return -ENOMEM; | |
224 | ||
225 | for (i = 0; i < size; i++) | |
226 | INIT_LIST_HEAD(et->table + i); | |
227 | ||
228 | return 0; | |
229 | } | |
230 | ||
e18b890b | 231 | static void exit_exception_table(struct exception_table *et, struct kmem_cache *mem) |
1da177e4 LT |
232 | { |
233 | struct list_head *slot; | |
234 | struct exception *ex, *next; | |
235 | int i, size; | |
236 | ||
237 | size = et->hash_mask + 1; | |
238 | for (i = 0; i < size; i++) { | |
239 | slot = et->table + i; | |
240 | ||
241 | list_for_each_entry_safe (ex, next, slot, hash_list) | |
242 | kmem_cache_free(mem, ex); | |
243 | } | |
244 | ||
245 | vfree(et->table); | |
246 | } | |
247 | ||
248 | static inline uint32_t exception_hash(struct exception_table *et, chunk_t chunk) | |
249 | { | |
250 | return chunk & et->hash_mask; | |
251 | } | |
252 | ||
253 | static void insert_exception(struct exception_table *eh, struct exception *e) | |
254 | { | |
255 | struct list_head *l = &eh->table[exception_hash(eh, e->old_chunk)]; | |
256 | list_add(&e->hash_list, l); | |
257 | } | |
258 | ||
259 | static inline void remove_exception(struct exception *e) | |
260 | { | |
261 | list_del(&e->hash_list); | |
262 | } | |
263 | ||
264 | /* | |
265 | * Return the exception data for a sector, or NULL if not | |
266 | * remapped. | |
267 | */ | |
268 | static struct exception *lookup_exception(struct exception_table *et, | |
269 | chunk_t chunk) | |
270 | { | |
271 | struct list_head *slot; | |
272 | struct exception *e; | |
273 | ||
274 | slot = &et->table[exception_hash(et, chunk)]; | |
275 | list_for_each_entry (e, slot, hash_list) | |
276 | if (e->old_chunk == chunk) | |
277 | return e; | |
278 | ||
279 | return NULL; | |
280 | } | |
281 | ||
282 | static inline struct exception *alloc_exception(void) | |
283 | { | |
284 | struct exception *e; | |
285 | ||
286 | e = kmem_cache_alloc(exception_cache, GFP_NOIO); | |
287 | if (!e) | |
288 | e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); | |
289 | ||
290 | return e; | |
291 | } | |
292 | ||
293 | static inline void free_exception(struct exception *e) | |
294 | { | |
295 | kmem_cache_free(exception_cache, e); | |
296 | } | |
297 | ||
298 | static inline struct pending_exception *alloc_pending_exception(void) | |
299 | { | |
300 | return mempool_alloc(pending_pool, GFP_NOIO); | |
301 | } | |
302 | ||
303 | static inline void free_pending_exception(struct pending_exception *pe) | |
304 | { | |
305 | mempool_free(pe, pending_pool); | |
306 | } | |
307 | ||
308 | int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new) | |
309 | { | |
310 | struct exception *e; | |
311 | ||
312 | e = alloc_exception(); | |
313 | if (!e) | |
314 | return -ENOMEM; | |
315 | ||
316 | e->old_chunk = old; | |
317 | e->new_chunk = new; | |
318 | insert_exception(&s->complete, e); | |
319 | return 0; | |
320 | } | |
321 | ||
322 | /* | |
323 | * Hard coded magic. | |
324 | */ | |
325 | static int calc_max_buckets(void) | |
326 | { | |
327 | /* use a fixed size of 2MB */ | |
328 | unsigned long mem = 2 * 1024 * 1024; | |
329 | mem /= sizeof(struct list_head); | |
330 | ||
331 | return mem; | |
332 | } | |
333 | ||
334 | /* | |
335 | * Rounds a number down to a power of 2. | |
336 | */ | |
337 | static inline uint32_t round_down(uint32_t n) | |
338 | { | |
339 | while (n & (n - 1)) | |
340 | n &= (n - 1); | |
341 | return n; | |
342 | } | |
343 | ||
344 | /* | |
345 | * Allocate room for a suitable hash table. | |
346 | */ | |
347 | static int init_hash_tables(struct dm_snapshot *s) | |
348 | { | |
349 | sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; | |
350 | ||
351 | /* | |
352 | * Calculate based on the size of the original volume or | |
353 | * the COW volume... | |
354 | */ | |
355 | cow_dev_size = get_dev_size(s->cow->bdev); | |
356 | origin_dev_size = get_dev_size(s->origin->bdev); | |
357 | max_buckets = calc_max_buckets(); | |
358 | ||
359 | hash_size = min(origin_dev_size, cow_dev_size) >> s->chunk_shift; | |
360 | hash_size = min(hash_size, max_buckets); | |
361 | ||
362 | /* Round it down to a power of 2 */ | |
363 | hash_size = round_down(hash_size); | |
364 | if (init_exception_table(&s->complete, hash_size)) | |
365 | return -ENOMEM; | |
366 | ||
367 | /* | |
368 | * Allocate hash table for in-flight exceptions | |
369 | * Make this smaller than the real hash table | |
370 | */ | |
371 | hash_size >>= 3; | |
372 | if (hash_size < 64) | |
373 | hash_size = 64; | |
374 | ||
375 | if (init_exception_table(&s->pending, hash_size)) { | |
376 | exit_exception_table(&s->complete, exception_cache); | |
377 | return -ENOMEM; | |
378 | } | |
379 | ||
380 | return 0; | |
381 | } | |
382 | ||
383 | /* | |
384 | * Round a number up to the nearest 'size' boundary. size must | |
385 | * be a power of 2. | |
386 | */ | |
387 | static inline ulong round_up(ulong n, ulong size) | |
388 | { | |
389 | size--; | |
390 | return (n + size) & ~size; | |
391 | } | |
392 | ||
4c7e3bf4 MM |
393 | static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg, |
394 | char **error) | |
395 | { | |
396 | unsigned long chunk_size; | |
397 | char *value; | |
398 | ||
399 | chunk_size = simple_strtoul(chunk_size_arg, &value, 10); | |
400 | if (*chunk_size_arg == '\0' || *value != '\0') { | |
401 | *error = "Invalid chunk size"; | |
402 | return -EINVAL; | |
403 | } | |
404 | ||
405 | if (!chunk_size) { | |
406 | s->chunk_size = s->chunk_mask = s->chunk_shift = 0; | |
407 | return 0; | |
408 | } | |
409 | ||
410 | /* | |
411 | * Chunk size must be multiple of page size. Silently | |
412 | * round up if it's not. | |
413 | */ | |
414 | chunk_size = round_up(chunk_size, PAGE_SIZE >> 9); | |
415 | ||
416 | /* Check chunk_size is a power of 2 */ | |
417 | if (chunk_size & (chunk_size - 1)) { | |
418 | *error = "Chunk size is not a power of 2"; | |
419 | return -EINVAL; | |
420 | } | |
421 | ||
422 | /* Validate the chunk size against the device block size */ | |
423 | if (chunk_size % (bdev_hardsect_size(s->cow->bdev) >> 9)) { | |
424 | *error = "Chunk size is not a multiple of device blocksize"; | |
425 | return -EINVAL; | |
426 | } | |
427 | ||
428 | s->chunk_size = chunk_size; | |
429 | s->chunk_mask = chunk_size - 1; | |
430 | s->chunk_shift = ffs(chunk_size) - 1; | |
431 | ||
432 | return 0; | |
433 | } | |
434 | ||
1da177e4 LT |
435 | /* |
436 | * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> | |
437 | */ | |
438 | static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
439 | { | |
440 | struct dm_snapshot *s; | |
1da177e4 LT |
441 | int r = -EINVAL; |
442 | char persistent; | |
443 | char *origin_path; | |
444 | char *cow_path; | |
1da177e4 | 445 | |
4c7e3bf4 | 446 | if (argc != 4) { |
72d94861 | 447 | ti->error = "requires exactly 4 arguments"; |
1da177e4 LT |
448 | r = -EINVAL; |
449 | goto bad1; | |
450 | } | |
451 | ||
452 | origin_path = argv[0]; | |
453 | cow_path = argv[1]; | |
454 | persistent = toupper(*argv[2]); | |
455 | ||
456 | if (persistent != 'P' && persistent != 'N') { | |
457 | ti->error = "Persistent flag is not P or N"; | |
458 | r = -EINVAL; | |
459 | goto bad1; | |
460 | } | |
461 | ||
1da177e4 LT |
462 | s = kmalloc(sizeof(*s), GFP_KERNEL); |
463 | if (s == NULL) { | |
464 | ti->error = "Cannot allocate snapshot context private " | |
465 | "structure"; | |
466 | r = -ENOMEM; | |
467 | goto bad1; | |
468 | } | |
469 | ||
470 | r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin); | |
471 | if (r) { | |
472 | ti->error = "Cannot get origin device"; | |
473 | goto bad2; | |
474 | } | |
475 | ||
476 | r = dm_get_device(ti, cow_path, 0, 0, | |
477 | FMODE_READ | FMODE_WRITE, &s->cow); | |
478 | if (r) { | |
479 | dm_put_device(ti, s->origin); | |
480 | ti->error = "Cannot get COW device"; | |
481 | goto bad2; | |
482 | } | |
483 | ||
4c7e3bf4 MM |
484 | r = set_chunk_size(s, argv[3], &ti->error); |
485 | if (r) | |
1da177e4 | 486 | goto bad3; |
1da177e4 | 487 | |
1da177e4 | 488 | s->type = persistent; |
1da177e4 LT |
489 | |
490 | s->valid = 1; | |
aa14edeb | 491 | s->active = 0; |
1da177e4 LT |
492 | s->last_percent = 0; |
493 | init_rwsem(&s->lock); | |
ca3a931f | 494 | spin_lock_init(&s->pe_lock); |
1da177e4 LT |
495 | s->table = ti->table; |
496 | ||
497 | /* Allocate hash table for COW data */ | |
498 | if (init_hash_tables(s)) { | |
499 | ti->error = "Unable to allocate hash table space"; | |
500 | r = -ENOMEM; | |
501 | goto bad3; | |
502 | } | |
503 | ||
1da177e4 LT |
504 | s->store.snap = s; |
505 | ||
506 | if (persistent == 'P') | |
4c7e3bf4 | 507 | r = dm_create_persistent(&s->store); |
1da177e4 | 508 | else |
4c7e3bf4 | 509 | r = dm_create_transient(&s->store); |
1da177e4 LT |
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 | 523 | /* Metadata must only be loaded into one table at once */ |
f9cea4f7 MM |
524 | r = s->store.read_metadata(&s->store); |
525 | if (r) { | |
526 | ti->error = "Failed to read snapshot metadata"; | |
527 | goto bad6; | |
528 | } | |
aa14edeb | 529 | |
ca3a931f | 530 | bio_list_init(&s->queued_bios); |
c4028958 | 531 | INIT_WORK(&s->queued_bios_work, flush_queued_bios); |
ca3a931f | 532 | |
1da177e4 | 533 | /* Add snapshot to the list of snapshots for this origin */ |
aa14edeb | 534 | /* Exceptions aren't triggered till snapshot_resume() is called */ |
1da177e4 LT |
535 | if (register_snapshot(s)) { |
536 | r = -EINVAL; | |
537 | ti->error = "Cannot register snapshot origin"; | |
538 | goto bad6; | |
539 | } | |
540 | ||
541 | ti->private = s; | |
c51c2752 | 542 | ti->split_io = s->chunk_size; |
1da177e4 LT |
543 | |
544 | return 0; | |
545 | ||
546 | bad6: | |
547 | kcopyd_client_destroy(s->kcopyd_client); | |
548 | ||
549 | bad5: | |
550 | s->store.destroy(&s->store); | |
551 | ||
552 | bad4: | |
553 | exit_exception_table(&s->pending, pending_cache); | |
554 | exit_exception_table(&s->complete, exception_cache); | |
555 | ||
556 | bad3: | |
557 | dm_put_device(ti, s->cow); | |
558 | dm_put_device(ti, s->origin); | |
559 | ||
560 | bad2: | |
561 | kfree(s); | |
562 | ||
563 | bad1: | |
564 | return r; | |
565 | } | |
566 | ||
31c93a0c MB |
567 | static void __free_exceptions(struct dm_snapshot *s) |
568 | { | |
569 | kcopyd_client_destroy(s->kcopyd_client); | |
570 | s->kcopyd_client = NULL; | |
571 | ||
572 | exit_exception_table(&s->pending, pending_cache); | |
573 | exit_exception_table(&s->complete, exception_cache); | |
574 | ||
575 | s->store.destroy(&s->store); | |
576 | } | |
577 | ||
1da177e4 LT |
578 | static void snapshot_dtr(struct dm_target *ti) |
579 | { | |
580 | struct dm_snapshot *s = (struct dm_snapshot *) ti->private; | |
581 | ||
ca3a931f AK |
582 | flush_workqueue(ksnapd); |
583 | ||
138728dc AK |
584 | /* Prevent further origin writes from using this snapshot. */ |
585 | /* After this returns there can be no new kcopyd jobs. */ | |
1da177e4 LT |
586 | unregister_snapshot(s); |
587 | ||
31c93a0c | 588 | __free_exceptions(s); |
1da177e4 LT |
589 | |
590 | dm_put_device(ti, s->origin); | |
591 | dm_put_device(ti, s->cow); | |
138728dc | 592 | |
1da177e4 LT |
593 | kfree(s); |
594 | } | |
595 | ||
596 | /* | |
597 | * Flush a list of buffers. | |
598 | */ | |
599 | static void flush_bios(struct bio *bio) | |
600 | { | |
601 | struct bio *n; | |
602 | ||
603 | while (bio) { | |
604 | n = bio->bi_next; | |
605 | bio->bi_next = NULL; | |
606 | generic_make_request(bio); | |
607 | bio = n; | |
608 | } | |
609 | } | |
610 | ||
c4028958 | 611 | static void flush_queued_bios(struct work_struct *work) |
ca3a931f | 612 | { |
c4028958 DH |
613 | struct dm_snapshot *s = |
614 | container_of(work, struct dm_snapshot, queued_bios_work); | |
ca3a931f AK |
615 | struct bio *queued_bios; |
616 | unsigned long flags; | |
617 | ||
618 | spin_lock_irqsave(&s->pe_lock, flags); | |
619 | queued_bios = bio_list_get(&s->queued_bios); | |
620 | spin_unlock_irqrestore(&s->pe_lock, flags); | |
621 | ||
622 | flush_bios(queued_bios); | |
623 | } | |
624 | ||
1da177e4 LT |
625 | /* |
626 | * Error a list of buffers. | |
627 | */ | |
628 | static void error_bios(struct bio *bio) | |
629 | { | |
630 | struct bio *n; | |
631 | ||
632 | while (bio) { | |
633 | n = bio->bi_next; | |
634 | bio->bi_next = NULL; | |
635 | bio_io_error(bio, bio->bi_size); | |
636 | bio = n; | |
637 | } | |
638 | } | |
639 | ||
695368ac | 640 | static void __invalidate_snapshot(struct dm_snapshot *s, int err) |
76df1c65 AK |
641 | { |
642 | if (!s->valid) | |
643 | return; | |
644 | ||
645 | if (err == -EIO) | |
646 | DMERR("Invalidating snapshot: Error reading/writing."); | |
647 | else if (err == -ENOMEM) | |
648 | DMERR("Invalidating snapshot: Unable to allocate exception."); | |
649 | ||
76df1c65 AK |
650 | if (s->store.drop_snapshot) |
651 | s->store.drop_snapshot(&s->store); | |
652 | ||
653 | s->valid = 0; | |
654 | ||
655 | dm_table_event(s->table); | |
656 | } | |
657 | ||
4b832e8d AK |
658 | static void get_pending_exception(struct pending_exception *pe) |
659 | { | |
660 | atomic_inc(&pe->ref_count); | |
661 | } | |
662 | ||
663 | static struct bio *put_pending_exception(struct pending_exception *pe) | |
664 | { | |
665 | struct pending_exception *primary_pe; | |
666 | struct bio *origin_bios = NULL; | |
667 | ||
668 | primary_pe = pe->primary_pe; | |
669 | ||
670 | /* | |
671 | * If this pe is involved in a write to the origin and | |
672 | * it is the last sibling to complete then release | |
673 | * the bios for the original write to the origin. | |
674 | */ | |
675 | if (primary_pe && | |
676 | atomic_dec_and_test(&primary_pe->ref_count)) | |
677 | origin_bios = bio_list_get(&primary_pe->origin_bios); | |
678 | ||
679 | /* | |
680 | * Free the pe if it's not linked to an origin write or if | |
681 | * it's not itself a primary pe. | |
682 | */ | |
683 | if (!primary_pe || primary_pe != pe) | |
684 | free_pending_exception(pe); | |
685 | ||
686 | /* | |
687 | * Free the primary pe if nothing references it. | |
688 | */ | |
689 | if (primary_pe && !atomic_read(&primary_pe->ref_count)) | |
690 | free_pending_exception(primary_pe); | |
691 | ||
692 | return origin_bios; | |
693 | } | |
694 | ||
1da177e4 LT |
695 | static void pending_complete(struct pending_exception *pe, int success) |
696 | { | |
697 | struct exception *e; | |
698 | struct dm_snapshot *s = pe->snap; | |
9d493fa8 AK |
699 | struct bio *origin_bios = NULL; |
700 | struct bio *snapshot_bios = NULL; | |
701 | int error = 0; | |
1da177e4 | 702 | |
76df1c65 AK |
703 | if (!success) { |
704 | /* Read/write error - snapshot is unusable */ | |
1da177e4 | 705 | down_write(&s->lock); |
695368ac | 706 | __invalidate_snapshot(s, -EIO); |
9d493fa8 | 707 | error = 1; |
76df1c65 AK |
708 | goto out; |
709 | } | |
710 | ||
711 | e = alloc_exception(); | |
712 | if (!e) { | |
1da177e4 | 713 | down_write(&s->lock); |
695368ac | 714 | __invalidate_snapshot(s, -ENOMEM); |
9d493fa8 | 715 | error = 1; |
76df1c65 AK |
716 | goto out; |
717 | } | |
718 | *e = pe->e; | |
1da177e4 | 719 | |
76df1c65 AK |
720 | down_write(&s->lock); |
721 | if (!s->valid) { | |
76df1c65 | 722 | free_exception(e); |
9d493fa8 | 723 | error = 1; |
76df1c65 | 724 | goto out; |
1da177e4 LT |
725 | } |
726 | ||
9d493fa8 AK |
727 | /* |
728 | * Add a proper exception, and remove the | |
729 | * in-flight exception from the list. | |
730 | */ | |
76df1c65 | 731 | insert_exception(&s->complete, e); |
76df1c65 | 732 | |
1da177e4 | 733 | out: |
695368ac | 734 | remove_exception(&pe->e); |
9d493fa8 | 735 | snapshot_bios = bio_list_get(&pe->snapshot_bios); |
4b832e8d | 736 | origin_bios = put_pending_exception(pe); |
1da177e4 | 737 | |
9d493fa8 AK |
738 | up_write(&s->lock); |
739 | ||
740 | /* Submit any pending write bios */ | |
741 | if (error) | |
742 | error_bios(snapshot_bios); | |
743 | else | |
744 | flush_bios(snapshot_bios); | |
745 | ||
746 | flush_bios(origin_bios); | |
1da177e4 LT |
747 | } |
748 | ||
749 | static void commit_callback(void *context, int success) | |
750 | { | |
751 | struct pending_exception *pe = (struct pending_exception *) context; | |
752 | pending_complete(pe, success); | |
753 | } | |
754 | ||
755 | /* | |
756 | * Called when the copy I/O has finished. kcopyd actually runs | |
757 | * this code so don't block. | |
758 | */ | |
759 | static void copy_callback(int read_err, unsigned int write_err, void *context) | |
760 | { | |
761 | struct pending_exception *pe = (struct pending_exception *) context; | |
762 | struct dm_snapshot *s = pe->snap; | |
763 | ||
764 | if (read_err || write_err) | |
765 | pending_complete(pe, 0); | |
766 | ||
767 | else | |
768 | /* Update the metadata if we are persistent */ | |
769 | s->store.commit_exception(&s->store, &pe->e, commit_callback, | |
770 | pe); | |
771 | } | |
772 | ||
773 | /* | |
774 | * Dispatches the copy operation to kcopyd. | |
775 | */ | |
858119e1 | 776 | static void start_copy(struct pending_exception *pe) |
1da177e4 LT |
777 | { |
778 | struct dm_snapshot *s = pe->snap; | |
779 | struct io_region src, dest; | |
780 | struct block_device *bdev = s->origin->bdev; | |
781 | sector_t dev_size; | |
782 | ||
783 | dev_size = get_dev_size(bdev); | |
784 | ||
785 | src.bdev = bdev; | |
786 | src.sector = chunk_to_sector(s, pe->e.old_chunk); | |
787 | src.count = min(s->chunk_size, dev_size - src.sector); | |
788 | ||
789 | dest.bdev = s->cow->bdev; | |
790 | dest.sector = chunk_to_sector(s, pe->e.new_chunk); | |
791 | dest.count = src.count; | |
792 | ||
793 | /* Hand over to kcopyd */ | |
794 | kcopyd_copy(s->kcopyd_client, | |
795 | &src, 1, &dest, 0, copy_callback, pe); | |
796 | } | |
797 | ||
798 | /* | |
799 | * Looks to see if this snapshot already has a pending exception | |
800 | * for this chunk, otherwise it allocates a new one and inserts | |
801 | * it into the pending table. | |
802 | * | |
803 | * NOTE: a write lock must be held on snap->lock before calling | |
804 | * this. | |
805 | */ | |
806 | static struct pending_exception * | |
807 | __find_pending_exception(struct dm_snapshot *s, struct bio *bio) | |
808 | { | |
809 | struct exception *e; | |
810 | struct pending_exception *pe; | |
811 | chunk_t chunk = sector_to_chunk(s, bio->bi_sector); | |
812 | ||
813 | /* | |
814 | * Is there a pending exception for this already ? | |
815 | */ | |
816 | e = lookup_exception(&s->pending, chunk); | |
817 | if (e) { | |
818 | /* cast the exception to a pending exception */ | |
819 | pe = container_of(e, struct pending_exception, e); | |
76df1c65 AK |
820 | goto out; |
821 | } | |
1da177e4 | 822 | |
76df1c65 AK |
823 | /* |
824 | * Create a new pending exception, we don't want | |
825 | * to hold the lock while we do this. | |
826 | */ | |
827 | up_write(&s->lock); | |
828 | pe = alloc_pending_exception(); | |
829 | down_write(&s->lock); | |
1da177e4 | 830 | |
76df1c65 AK |
831 | if (!s->valid) { |
832 | free_pending_exception(pe); | |
833 | return NULL; | |
834 | } | |
1da177e4 | 835 | |
76df1c65 AK |
836 | e = lookup_exception(&s->pending, chunk); |
837 | if (e) { | |
838 | free_pending_exception(pe); | |
839 | pe = container_of(e, struct pending_exception, e); | |
840 | goto out; | |
1da177e4 LT |
841 | } |
842 | ||
76df1c65 AK |
843 | pe->e.old_chunk = chunk; |
844 | bio_list_init(&pe->origin_bios); | |
845 | bio_list_init(&pe->snapshot_bios); | |
846 | pe->primary_pe = NULL; | |
4b832e8d | 847 | atomic_set(&pe->ref_count, 0); |
76df1c65 AK |
848 | pe->snap = s; |
849 | pe->started = 0; | |
850 | ||
851 | if (s->store.prepare_exception(&s->store, &pe->e)) { | |
852 | free_pending_exception(pe); | |
853 | return NULL; | |
854 | } | |
855 | ||
4b832e8d | 856 | get_pending_exception(pe); |
76df1c65 AK |
857 | insert_exception(&s->pending, &pe->e); |
858 | ||
859 | out: | |
1da177e4 LT |
860 | return pe; |
861 | } | |
862 | ||
863 | static inline void remap_exception(struct dm_snapshot *s, struct exception *e, | |
864 | struct bio *bio) | |
865 | { | |
866 | bio->bi_bdev = s->cow->bdev; | |
867 | bio->bi_sector = chunk_to_sector(s, e->new_chunk) + | |
868 | (bio->bi_sector & s->chunk_mask); | |
869 | } | |
870 | ||
871 | static int snapshot_map(struct dm_target *ti, struct bio *bio, | |
872 | union map_info *map_context) | |
873 | { | |
874 | struct exception *e; | |
875 | struct dm_snapshot *s = (struct dm_snapshot *) ti->private; | |
d2a7ad29 | 876 | int r = DM_MAPIO_REMAPPED; |
1da177e4 | 877 | chunk_t chunk; |
76df1c65 | 878 | struct pending_exception *pe = NULL; |
1da177e4 LT |
879 | |
880 | chunk = sector_to_chunk(s, bio->bi_sector); | |
881 | ||
882 | /* Full snapshots are not usable */ | |
76df1c65 | 883 | /* To get here the table must be live so s->active is always set. */ |
1da177e4 | 884 | if (!s->valid) |
f6a80ea8 | 885 | return -EIO; |
1da177e4 | 886 | |
4aac0a63 AK |
887 | if (unlikely(bio_barrier(bio))) |
888 | return -EOPNOTSUPP; | |
889 | ||
ba40a2aa AK |
890 | /* FIXME: should only take write lock if we need |
891 | * to copy an exception */ | |
892 | down_write(&s->lock); | |
893 | ||
894 | if (!s->valid) { | |
895 | r = -EIO; | |
896 | goto out_unlock; | |
897 | } | |
898 | ||
899 | /* If the block is already remapped - use that, else remap it */ | |
900 | e = lookup_exception(&s->complete, chunk); | |
901 | if (e) { | |
902 | remap_exception(s, e, bio); | |
903 | goto out_unlock; | |
904 | } | |
905 | ||
1da177e4 LT |
906 | /* |
907 | * Write to snapshot - higher level takes care of RW/RO | |
908 | * flags so we should only get this if we are | |
909 | * writeable. | |
910 | */ | |
911 | if (bio_rw(bio) == WRITE) { | |
76df1c65 AK |
912 | pe = __find_pending_exception(s, bio); |
913 | if (!pe) { | |
695368ac | 914 | __invalidate_snapshot(s, -ENOMEM); |
76df1c65 AK |
915 | r = -EIO; |
916 | goto out_unlock; | |
1da177e4 LT |
917 | } |
918 | ||
76df1c65 AK |
919 | remap_exception(s, &pe->e, bio); |
920 | bio_list_add(&pe->snapshot_bios, bio); | |
921 | ||
d2a7ad29 | 922 | r = DM_MAPIO_SUBMITTED; |
ba40a2aa | 923 | |
76df1c65 AK |
924 | if (!pe->started) { |
925 | /* this is protected by snap->lock */ | |
926 | pe->started = 1; | |
ba40a2aa | 927 | up_write(&s->lock); |
76df1c65 | 928 | start_copy(pe); |
ba40a2aa AK |
929 | goto out; |
930 | } | |
931 | } else | |
1da177e4 LT |
932 | /* |
933 | * FIXME: this read path scares me because we | |
934 | * always use the origin when we have a pending | |
935 | * exception. However I can't think of a | |
936 | * situation where this is wrong - ejt. | |
937 | */ | |
ba40a2aa | 938 | bio->bi_bdev = s->origin->bdev; |
1da177e4 | 939 | |
ba40a2aa AK |
940 | out_unlock: |
941 | up_write(&s->lock); | |
942 | out: | |
1da177e4 LT |
943 | return r; |
944 | } | |
945 | ||
946 | static void snapshot_resume(struct dm_target *ti) | |
947 | { | |
948 | struct dm_snapshot *s = (struct dm_snapshot *) ti->private; | |
949 | ||
aa14edeb AK |
950 | down_write(&s->lock); |
951 | s->active = 1; | |
952 | up_write(&s->lock); | |
1da177e4 LT |
953 | } |
954 | ||
955 | static int snapshot_status(struct dm_target *ti, status_type_t type, | |
956 | char *result, unsigned int maxlen) | |
957 | { | |
958 | struct dm_snapshot *snap = (struct dm_snapshot *) ti->private; | |
959 | ||
960 | switch (type) { | |
961 | case STATUSTYPE_INFO: | |
962 | if (!snap->valid) | |
963 | snprintf(result, maxlen, "Invalid"); | |
964 | else { | |
965 | if (snap->store.fraction_full) { | |
966 | sector_t numerator, denominator; | |
967 | snap->store.fraction_full(&snap->store, | |
968 | &numerator, | |
969 | &denominator); | |
4ee218cd AM |
970 | snprintf(result, maxlen, "%llu/%llu", |
971 | (unsigned long long)numerator, | |
972 | (unsigned long long)denominator); | |
1da177e4 LT |
973 | } |
974 | else | |
975 | snprintf(result, maxlen, "Unknown"); | |
976 | } | |
977 | break; | |
978 | ||
979 | case STATUSTYPE_TABLE: | |
980 | /* | |
981 | * kdevname returns a static pointer so we need | |
982 | * to make private copies if the output is to | |
983 | * make sense. | |
984 | */ | |
4ee218cd | 985 | snprintf(result, maxlen, "%s %s %c %llu", |
1da177e4 | 986 | snap->origin->name, snap->cow->name, |
4ee218cd AM |
987 | snap->type, |
988 | (unsigned long long)snap->chunk_size); | |
1da177e4 LT |
989 | break; |
990 | } | |
991 | ||
992 | return 0; | |
993 | } | |
994 | ||
995 | /*----------------------------------------------------------------- | |
996 | * Origin methods | |
997 | *---------------------------------------------------------------*/ | |
1da177e4 LT |
998 | static int __origin_write(struct list_head *snapshots, struct bio *bio) |
999 | { | |
d2a7ad29 | 1000 | int r = DM_MAPIO_REMAPPED, first = 0; |
1da177e4 LT |
1001 | struct dm_snapshot *snap; |
1002 | struct exception *e; | |
b4b610f6 | 1003 | struct pending_exception *pe, *next_pe, *primary_pe = NULL; |
1da177e4 | 1004 | chunk_t chunk; |
eccf0817 | 1005 | LIST_HEAD(pe_queue); |
1da177e4 LT |
1006 | |
1007 | /* Do all the snapshots on this origin */ | |
1008 | list_for_each_entry (snap, snapshots, list) { | |
1009 | ||
76df1c65 AK |
1010 | down_write(&snap->lock); |
1011 | ||
aa14edeb AK |
1012 | /* Only deal with valid and active snapshots */ |
1013 | if (!snap->valid || !snap->active) | |
76df1c65 | 1014 | goto next_snapshot; |
1da177e4 | 1015 | |
d5e404c1 AK |
1016 | /* Nothing to do if writing beyond end of snapshot */ |
1017 | if (bio->bi_sector >= dm_table_get_size(snap->table)) | |
76df1c65 | 1018 | goto next_snapshot; |
1da177e4 LT |
1019 | |
1020 | /* | |
1021 | * Remember, different snapshots can have | |
1022 | * different chunk sizes. | |
1023 | */ | |
1024 | chunk = sector_to_chunk(snap, bio->bi_sector); | |
1025 | ||
1026 | /* | |
1027 | * Check exception table to see if block | |
1028 | * is already remapped in this snapshot | |
1029 | * and trigger an exception if not. | |
b4b610f6 | 1030 | * |
4b832e8d | 1031 | * ref_count is initialised to 1 so pending_complete() |
b4b610f6 | 1032 | * won't destroy the primary_pe while we're inside this loop. |
1da177e4 LT |
1033 | */ |
1034 | e = lookup_exception(&snap->complete, chunk); | |
76df1c65 AK |
1035 | if (e) |
1036 | goto next_snapshot; | |
1037 | ||
1038 | pe = __find_pending_exception(snap, bio); | |
1039 | if (!pe) { | |
695368ac | 1040 | __invalidate_snapshot(snap, -ENOMEM); |
76df1c65 AK |
1041 | goto next_snapshot; |
1042 | } | |
1043 | ||
1044 | if (!primary_pe) { | |
1045 | /* | |
1046 | * Either every pe here has same | |
1047 | * primary_pe or none has one yet. | |
1048 | */ | |
1049 | if (pe->primary_pe) | |
1050 | primary_pe = pe->primary_pe; | |
1051 | else { | |
1052 | primary_pe = pe; | |
1053 | first = 1; | |
1da177e4 | 1054 | } |
76df1c65 AK |
1055 | |
1056 | bio_list_add(&primary_pe->origin_bios, bio); | |
1057 | ||
d2a7ad29 | 1058 | r = DM_MAPIO_SUBMITTED; |
76df1c65 AK |
1059 | } |
1060 | ||
1061 | if (!pe->primary_pe) { | |
76df1c65 | 1062 | pe->primary_pe = primary_pe; |
4b832e8d | 1063 | get_pending_exception(primary_pe); |
76df1c65 AK |
1064 | } |
1065 | ||
1066 | if (!pe->started) { | |
1067 | pe->started = 1; | |
1068 | list_add_tail(&pe->list, &pe_queue); | |
1da177e4 LT |
1069 | } |
1070 | ||
76df1c65 | 1071 | next_snapshot: |
1da177e4 LT |
1072 | up_write(&snap->lock); |
1073 | } | |
1074 | ||
b4b610f6 | 1075 | if (!primary_pe) |
4b832e8d | 1076 | return r; |
b4b610f6 AK |
1077 | |
1078 | /* | |
1079 | * If this is the first time we're processing this chunk and | |
4b832e8d | 1080 | * ref_count is now 1 it means all the pending exceptions |
b4b610f6 AK |
1081 | * got completed while we were in the loop above, so it falls to |
1082 | * us here to remove the primary_pe and submit any origin_bios. | |
1083 | */ | |
1084 | ||
4b832e8d | 1085 | if (first && atomic_dec_and_test(&primary_pe->ref_count)) { |
b4b610f6 AK |
1086 | flush_bios(bio_list_get(&primary_pe->origin_bios)); |
1087 | free_pending_exception(primary_pe); | |
1088 | /* If we got here, pe_queue is necessarily empty. */ | |
4b832e8d | 1089 | return r; |
b4b610f6 AK |
1090 | } |
1091 | ||
1da177e4 LT |
1092 | /* |
1093 | * Now that we have a complete pe list we can start the copying. | |
1094 | */ | |
eccf0817 AK |
1095 | list_for_each_entry_safe(pe, next_pe, &pe_queue, list) |
1096 | start_copy(pe); | |
1da177e4 LT |
1097 | |
1098 | return r; | |
1099 | } | |
1100 | ||
1101 | /* | |
1102 | * Called on a write from the origin driver. | |
1103 | */ | |
1104 | static int do_origin(struct dm_dev *origin, struct bio *bio) | |
1105 | { | |
1106 | struct origin *o; | |
d2a7ad29 | 1107 | int r = DM_MAPIO_REMAPPED; |
1da177e4 LT |
1108 | |
1109 | down_read(&_origins_lock); | |
1110 | o = __lookup_origin(origin->bdev); | |
1111 | if (o) | |
1112 | r = __origin_write(&o->snapshots, bio); | |
1113 | up_read(&_origins_lock); | |
1114 | ||
1115 | return r; | |
1116 | } | |
1117 | ||
1118 | /* | |
1119 | * Origin: maps a linear range of a device, with hooks for snapshotting. | |
1120 | */ | |
1121 | ||
1122 | /* | |
1123 | * Construct an origin mapping: <dev_path> | |
1124 | * The context for an origin is merely a 'struct dm_dev *' | |
1125 | * pointing to the real device. | |
1126 | */ | |
1127 | static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
1128 | { | |
1129 | int r; | |
1130 | struct dm_dev *dev; | |
1131 | ||
1132 | if (argc != 1) { | |
72d94861 | 1133 | ti->error = "origin: incorrect number of arguments"; |
1da177e4 LT |
1134 | return -EINVAL; |
1135 | } | |
1136 | ||
1137 | r = dm_get_device(ti, argv[0], 0, ti->len, | |
1138 | dm_table_get_mode(ti->table), &dev); | |
1139 | if (r) { | |
1140 | ti->error = "Cannot get target device"; | |
1141 | return r; | |
1142 | } | |
1143 | ||
1144 | ti->private = dev; | |
1145 | return 0; | |
1146 | } | |
1147 | ||
1148 | static void origin_dtr(struct dm_target *ti) | |
1149 | { | |
1150 | struct dm_dev *dev = (struct dm_dev *) ti->private; | |
1151 | dm_put_device(ti, dev); | |
1152 | } | |
1153 | ||
1154 | static int origin_map(struct dm_target *ti, struct bio *bio, | |
1155 | union map_info *map_context) | |
1156 | { | |
1157 | struct dm_dev *dev = (struct dm_dev *) ti->private; | |
1158 | bio->bi_bdev = dev->bdev; | |
1159 | ||
4aac0a63 AK |
1160 | if (unlikely(bio_barrier(bio))) |
1161 | return -EOPNOTSUPP; | |
1162 | ||
1da177e4 | 1163 | /* Only tell snapshots if this is a write */ |
d2a7ad29 | 1164 | return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; |
1da177e4 LT |
1165 | } |
1166 | ||
1167 | #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) | |
1168 | ||
1169 | /* | |
1170 | * Set the target "split_io" field to the minimum of all the snapshots' | |
1171 | * chunk sizes. | |
1172 | */ | |
1173 | static void origin_resume(struct dm_target *ti) | |
1174 | { | |
1175 | struct dm_dev *dev = (struct dm_dev *) ti->private; | |
1176 | struct dm_snapshot *snap; | |
1177 | struct origin *o; | |
1178 | chunk_t chunk_size = 0; | |
1179 | ||
1180 | down_read(&_origins_lock); | |
1181 | o = __lookup_origin(dev->bdev); | |
1182 | if (o) | |
1183 | list_for_each_entry (snap, &o->snapshots, list) | |
1184 | chunk_size = min_not_zero(chunk_size, snap->chunk_size); | |
1185 | up_read(&_origins_lock); | |
1186 | ||
1187 | ti->split_io = chunk_size; | |
1188 | } | |
1189 | ||
1190 | static int origin_status(struct dm_target *ti, status_type_t type, char *result, | |
1191 | unsigned int maxlen) | |
1192 | { | |
1193 | struct dm_dev *dev = (struct dm_dev *) ti->private; | |
1194 | ||
1195 | switch (type) { | |
1196 | case STATUSTYPE_INFO: | |
1197 | result[0] = '\0'; | |
1198 | break; | |
1199 | ||
1200 | case STATUSTYPE_TABLE: | |
1201 | snprintf(result, maxlen, "%s", dev->name); | |
1202 | break; | |
1203 | } | |
1204 | ||
1205 | return 0; | |
1206 | } | |
1207 | ||
1208 | static struct target_type origin_target = { | |
1209 | .name = "snapshot-origin", | |
4c7e3bf4 | 1210 | .version = {1, 5, 0}, |
1da177e4 LT |
1211 | .module = THIS_MODULE, |
1212 | .ctr = origin_ctr, | |
1213 | .dtr = origin_dtr, | |
1214 | .map = origin_map, | |
1215 | .resume = origin_resume, | |
1216 | .status = origin_status, | |
1217 | }; | |
1218 | ||
1219 | static struct target_type snapshot_target = { | |
1220 | .name = "snapshot", | |
4c7e3bf4 | 1221 | .version = {1, 5, 0}, |
1da177e4 LT |
1222 | .module = THIS_MODULE, |
1223 | .ctr = snapshot_ctr, | |
1224 | .dtr = snapshot_dtr, | |
1225 | .map = snapshot_map, | |
1226 | .resume = snapshot_resume, | |
1227 | .status = snapshot_status, | |
1228 | }; | |
1229 | ||
1230 | static int __init dm_snapshot_init(void) | |
1231 | { | |
1232 | int r; | |
1233 | ||
1234 | r = dm_register_target(&snapshot_target); | |
1235 | if (r) { | |
1236 | DMERR("snapshot target register failed %d", r); | |
1237 | return r; | |
1238 | } | |
1239 | ||
1240 | r = dm_register_target(&origin_target); | |
1241 | if (r < 0) { | |
72d94861 | 1242 | DMERR("Origin target register failed %d", r); |
1da177e4 LT |
1243 | goto bad1; |
1244 | } | |
1245 | ||
1246 | r = init_origin_hash(); | |
1247 | if (r) { | |
1248 | DMERR("init_origin_hash failed."); | |
1249 | goto bad2; | |
1250 | } | |
1251 | ||
1252 | exception_cache = kmem_cache_create("dm-snapshot-ex", | |
1253 | sizeof(struct exception), | |
1254 | __alignof__(struct exception), | |
1255 | 0, NULL, NULL); | |
1256 | if (!exception_cache) { | |
1257 | DMERR("Couldn't create exception cache."); | |
1258 | r = -ENOMEM; | |
1259 | goto bad3; | |
1260 | } | |
1261 | ||
1262 | pending_cache = | |
1263 | kmem_cache_create("dm-snapshot-in", | |
1264 | sizeof(struct pending_exception), | |
1265 | __alignof__(struct pending_exception), | |
1266 | 0, NULL, NULL); | |
1267 | if (!pending_cache) { | |
1268 | DMERR("Couldn't create pending cache."); | |
1269 | r = -ENOMEM; | |
1270 | goto bad4; | |
1271 | } | |
1272 | ||
93d2341c | 1273 | pending_pool = mempool_create_slab_pool(128, pending_cache); |
1da177e4 LT |
1274 | if (!pending_pool) { |
1275 | DMERR("Couldn't create pending pool."); | |
1276 | r = -ENOMEM; | |
1277 | goto bad5; | |
1278 | } | |
1279 | ||
ca3a931f AK |
1280 | ksnapd = create_singlethread_workqueue("ksnapd"); |
1281 | if (!ksnapd) { | |
1282 | DMERR("Failed to create ksnapd workqueue."); | |
1283 | r = -ENOMEM; | |
1284 | goto bad6; | |
1285 | } | |
1286 | ||
1da177e4 LT |
1287 | return 0; |
1288 | ||
ca3a931f AK |
1289 | bad6: |
1290 | mempool_destroy(pending_pool); | |
1da177e4 LT |
1291 | bad5: |
1292 | kmem_cache_destroy(pending_cache); | |
1293 | bad4: | |
1294 | kmem_cache_destroy(exception_cache); | |
1295 | bad3: | |
1296 | exit_origin_hash(); | |
1297 | bad2: | |
1298 | dm_unregister_target(&origin_target); | |
1299 | bad1: | |
1300 | dm_unregister_target(&snapshot_target); | |
1301 | return r; | |
1302 | } | |
1303 | ||
1304 | static void __exit dm_snapshot_exit(void) | |
1305 | { | |
1306 | int r; | |
1307 | ||
ca3a931f AK |
1308 | destroy_workqueue(ksnapd); |
1309 | ||
1da177e4 LT |
1310 | r = dm_unregister_target(&snapshot_target); |
1311 | if (r) | |
1312 | DMERR("snapshot unregister failed %d", r); | |
1313 | ||
1314 | r = dm_unregister_target(&origin_target); | |
1315 | if (r) | |
1316 | DMERR("origin unregister failed %d", r); | |
1317 | ||
1318 | exit_origin_hash(); | |
1319 | mempool_destroy(pending_pool); | |
1320 | kmem_cache_destroy(pending_cache); | |
1321 | kmem_cache_destroy(exception_cache); | |
1322 | } | |
1323 | ||
1324 | /* Module hooks */ | |
1325 | module_init(dm_snapshot_init); | |
1326 | module_exit(dm_snapshot_exit); | |
1327 | ||
1328 | MODULE_DESCRIPTION(DM_NAME " snapshot target"); | |
1329 | MODULE_AUTHOR("Joe Thornber"); | |
1330 | MODULE_LICENSE("GPL"); |