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 | 10 | #include <linux/device-mapper.h> |
90fa1527 | 11 | #include <linux/delay.h> |
1da177e4 LT |
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> | |
6f3c3f0a | 20 | #include <linux/log2.h> |
a765e20e | 21 | #include <linux/dm-kcopyd.h> |
1da177e4 | 22 | |
aea53d92 | 23 | #include "dm-exception-store.h" |
1da177e4 | 24 | |
72d94861 AK |
25 | #define DM_MSG_PREFIX "snapshots" |
26 | ||
d698aa45 MP |
27 | static const char dm_snapshot_merge_target_name[] = "snapshot-merge"; |
28 | ||
29 | #define dm_target_is_snapshot_merge(ti) \ | |
30 | ((ti)->type->name == dm_snapshot_merge_target_name) | |
31 | ||
cd45daff MP |
32 | /* |
33 | * The size of the mempool used to track chunks in use. | |
34 | */ | |
35 | #define MIN_IOS 256 | |
36 | ||
ccc45ea8 JB |
37 | #define DM_TRACKED_CHUNK_HASH_SIZE 16 |
38 | #define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \ | |
39 | (DM_TRACKED_CHUNK_HASH_SIZE - 1)) | |
40 | ||
191437a5 | 41 | struct dm_exception_table { |
ccc45ea8 JB |
42 | uint32_t hash_mask; |
43 | unsigned hash_shift; | |
44 | struct list_head *table; | |
45 | }; | |
46 | ||
47 | struct dm_snapshot { | |
48 | struct rw_semaphore lock; | |
49 | ||
50 | struct dm_dev *origin; | |
fc56f6fb MS |
51 | struct dm_dev *cow; |
52 | ||
53 | struct dm_target *ti; | |
ccc45ea8 JB |
54 | |
55 | /* List of snapshots per Origin */ | |
56 | struct list_head list; | |
57 | ||
d8ddb1cf MS |
58 | /* |
59 | * You can't use a snapshot if this is 0 (e.g. if full). | |
60 | * A snapshot-merge target never clears this. | |
61 | */ | |
ccc45ea8 JB |
62 | int valid; |
63 | ||
64 | /* Origin writes don't trigger exceptions until this is set */ | |
65 | int active; | |
66 | ||
ccc45ea8 JB |
67 | atomic_t pending_exceptions_count; |
68 | ||
924e600d MS |
69 | mempool_t *pending_pool; |
70 | ||
191437a5 JB |
71 | struct dm_exception_table pending; |
72 | struct dm_exception_table complete; | |
ccc45ea8 JB |
73 | |
74 | /* | |
75 | * pe_lock protects all pending_exception operations and access | |
76 | * as well as the snapshot_bios list. | |
77 | */ | |
78 | spinlock_t pe_lock; | |
79 | ||
924e600d MS |
80 | /* Chunks with outstanding reads */ |
81 | spinlock_t tracked_chunk_lock; | |
82 | mempool_t *tracked_chunk_pool; | |
83 | struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE]; | |
84 | ||
ccc45ea8 JB |
85 | /* The on disk metadata handler */ |
86 | struct dm_exception_store *store; | |
87 | ||
88 | struct dm_kcopyd_client *kcopyd_client; | |
89 | ||
924e600d MS |
90 | /* Wait for events based on state_bits */ |
91 | unsigned long state_bits; | |
92 | ||
93 | /* Range of chunks currently being merged. */ | |
94 | chunk_t first_merging_chunk; | |
95 | int num_merging_chunks; | |
1e03f97e | 96 | |
d8ddb1cf MS |
97 | /* |
98 | * The merge operation failed if this flag is set. | |
99 | * Failure modes are handled as follows: | |
100 | * - I/O error reading the header | |
101 | * => don't load the target; abort. | |
102 | * - Header does not have "valid" flag set | |
103 | * => use the origin; forget about the snapshot. | |
104 | * - I/O error when reading exceptions | |
105 | * => don't load the target; abort. | |
106 | * (We can't use the intermediate origin state.) | |
107 | * - I/O error while merging | |
108 | * => stop merging; set merge_failed; process I/O normally. | |
109 | */ | |
110 | int merge_failed; | |
111 | ||
9fe86254 MP |
112 | /* |
113 | * Incoming bios that overlap with chunks being merged must wait | |
114 | * for them to be committed. | |
115 | */ | |
116 | struct bio_list bios_queued_during_merge; | |
ccc45ea8 JB |
117 | }; |
118 | ||
1e03f97e MP |
119 | /* |
120 | * state_bits: | |
121 | * RUNNING_MERGE - Merge operation is in progress. | |
122 | * SHUTDOWN_MERGE - Set to signal that merge needs to be stopped; | |
123 | * cleared afterwards. | |
124 | */ | |
125 | #define RUNNING_MERGE 0 | |
126 | #define SHUTDOWN_MERGE 1 | |
127 | ||
c2411045 MP |
128 | struct dm_dev *dm_snap_origin(struct dm_snapshot *s) |
129 | { | |
130 | return s->origin; | |
131 | } | |
132 | EXPORT_SYMBOL(dm_snap_origin); | |
133 | ||
fc56f6fb MS |
134 | struct dm_dev *dm_snap_cow(struct dm_snapshot *s) |
135 | { | |
136 | return s->cow; | |
137 | } | |
138 | EXPORT_SYMBOL(dm_snap_cow); | |
139 | ||
ccc45ea8 JB |
140 | static sector_t chunk_to_sector(struct dm_exception_store *store, |
141 | chunk_t chunk) | |
142 | { | |
143 | return chunk << store->chunk_shift; | |
144 | } | |
145 | ||
146 | static int bdev_equal(struct block_device *lhs, struct block_device *rhs) | |
147 | { | |
148 | /* | |
149 | * There is only ever one instance of a particular block | |
150 | * device so we can compare pointers safely. | |
151 | */ | |
152 | return lhs == rhs; | |
153 | } | |
154 | ||
028867ac | 155 | struct dm_snap_pending_exception { |
1d4989c8 | 156 | struct dm_exception e; |
1da177e4 LT |
157 | |
158 | /* | |
159 | * Origin buffers waiting for this to complete are held | |
160 | * in a bio list | |
161 | */ | |
162 | struct bio_list origin_bios; | |
163 | struct bio_list snapshot_bios; | |
164 | ||
1da177e4 LT |
165 | /* Pointer back to snapshot context */ |
166 | struct dm_snapshot *snap; | |
167 | ||
168 | /* | |
169 | * 1 indicates the exception has already been sent to | |
170 | * kcopyd. | |
171 | */ | |
172 | int started; | |
173 | }; | |
174 | ||
175 | /* | |
176 | * Hash table mapping origin volumes to lists of snapshots and | |
177 | * a lock to protect it | |
178 | */ | |
e18b890b CL |
179 | static struct kmem_cache *exception_cache; |
180 | static struct kmem_cache *pending_cache; | |
1da177e4 | 181 | |
cd45daff MP |
182 | struct dm_snap_tracked_chunk { |
183 | struct hlist_node node; | |
184 | chunk_t chunk; | |
185 | }; | |
186 | ||
187 | static struct kmem_cache *tracked_chunk_cache; | |
188 | ||
189 | static struct dm_snap_tracked_chunk *track_chunk(struct dm_snapshot *s, | |
190 | chunk_t chunk) | |
191 | { | |
192 | struct dm_snap_tracked_chunk *c = mempool_alloc(s->tracked_chunk_pool, | |
193 | GFP_NOIO); | |
194 | unsigned long flags; | |
195 | ||
196 | c->chunk = chunk; | |
197 | ||
198 | spin_lock_irqsave(&s->tracked_chunk_lock, flags); | |
199 | hlist_add_head(&c->node, | |
200 | &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)]); | |
201 | spin_unlock_irqrestore(&s->tracked_chunk_lock, flags); | |
202 | ||
203 | return c; | |
204 | } | |
205 | ||
206 | static void stop_tracking_chunk(struct dm_snapshot *s, | |
207 | struct dm_snap_tracked_chunk *c) | |
208 | { | |
209 | unsigned long flags; | |
210 | ||
211 | spin_lock_irqsave(&s->tracked_chunk_lock, flags); | |
212 | hlist_del(&c->node); | |
213 | spin_unlock_irqrestore(&s->tracked_chunk_lock, flags); | |
214 | ||
215 | mempool_free(c, s->tracked_chunk_pool); | |
216 | } | |
217 | ||
a8d41b59 MP |
218 | static int __chunk_is_tracked(struct dm_snapshot *s, chunk_t chunk) |
219 | { | |
220 | struct dm_snap_tracked_chunk *c; | |
221 | struct hlist_node *hn; | |
222 | int found = 0; | |
223 | ||
224 | spin_lock_irq(&s->tracked_chunk_lock); | |
225 | ||
226 | hlist_for_each_entry(c, hn, | |
227 | &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)], node) { | |
228 | if (c->chunk == chunk) { | |
229 | found = 1; | |
230 | break; | |
231 | } | |
232 | } | |
233 | ||
234 | spin_unlock_irq(&s->tracked_chunk_lock); | |
235 | ||
236 | return found; | |
237 | } | |
238 | ||
615d1eb9 MS |
239 | /* |
240 | * This conflicting I/O is extremely improbable in the caller, | |
241 | * so msleep(1) is sufficient and there is no need for a wait queue. | |
242 | */ | |
243 | static void __check_for_conflicting_io(struct dm_snapshot *s, chunk_t chunk) | |
244 | { | |
245 | while (__chunk_is_tracked(s, chunk)) | |
246 | msleep(1); | |
247 | } | |
248 | ||
1da177e4 LT |
249 | /* |
250 | * One of these per registered origin, held in the snapshot_origins hash | |
251 | */ | |
252 | struct origin { | |
253 | /* The origin device */ | |
254 | struct block_device *bdev; | |
255 | ||
256 | struct list_head hash_list; | |
257 | ||
258 | /* List of snapshots for this origin */ | |
259 | struct list_head snapshots; | |
260 | }; | |
261 | ||
262 | /* | |
263 | * Size of the hash table for origin volumes. If we make this | |
264 | * the size of the minors list then it should be nearly perfect | |
265 | */ | |
266 | #define ORIGIN_HASH_SIZE 256 | |
267 | #define ORIGIN_MASK 0xFF | |
268 | static struct list_head *_origins; | |
269 | static struct rw_semaphore _origins_lock; | |
270 | ||
73dfd078 MP |
271 | static DECLARE_WAIT_QUEUE_HEAD(_pending_exceptions_done); |
272 | static DEFINE_SPINLOCK(_pending_exceptions_done_spinlock); | |
273 | static uint64_t _pending_exceptions_done_count; | |
274 | ||
1da177e4 LT |
275 | static int init_origin_hash(void) |
276 | { | |
277 | int i; | |
278 | ||
279 | _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), | |
280 | GFP_KERNEL); | |
281 | if (!_origins) { | |
72d94861 | 282 | DMERR("unable to allocate memory"); |
1da177e4 LT |
283 | return -ENOMEM; |
284 | } | |
285 | ||
286 | for (i = 0; i < ORIGIN_HASH_SIZE; i++) | |
287 | INIT_LIST_HEAD(_origins + i); | |
288 | init_rwsem(&_origins_lock); | |
289 | ||
290 | return 0; | |
291 | } | |
292 | ||
293 | static void exit_origin_hash(void) | |
294 | { | |
295 | kfree(_origins); | |
296 | } | |
297 | ||
028867ac | 298 | static unsigned origin_hash(struct block_device *bdev) |
1da177e4 LT |
299 | { |
300 | return bdev->bd_dev & ORIGIN_MASK; | |
301 | } | |
302 | ||
303 | static struct origin *__lookup_origin(struct block_device *origin) | |
304 | { | |
305 | struct list_head *ol; | |
306 | struct origin *o; | |
307 | ||
308 | ol = &_origins[origin_hash(origin)]; | |
309 | list_for_each_entry (o, ol, hash_list) | |
310 | if (bdev_equal(o->bdev, origin)) | |
311 | return o; | |
312 | ||
313 | return NULL; | |
314 | } | |
315 | ||
316 | static void __insert_origin(struct origin *o) | |
317 | { | |
318 | struct list_head *sl = &_origins[origin_hash(o->bdev)]; | |
319 | list_add_tail(&o->hash_list, sl); | |
320 | } | |
321 | ||
c1f0c183 MS |
322 | /* |
323 | * _origins_lock must be held when calling this function. | |
324 | * Returns number of snapshots registered using the supplied cow device, plus: | |
325 | * snap_src - a snapshot suitable for use as a source of exception handover | |
326 | * snap_dest - a snapshot capable of receiving exception handover. | |
9d3b15c4 MP |
327 | * snap_merge - an existing snapshot-merge target linked to the same origin. |
328 | * There can be at most one snapshot-merge target. The parameter is optional. | |
c1f0c183 | 329 | * |
9d3b15c4 | 330 | * Possible return values and states of snap_src and snap_dest. |
c1f0c183 MS |
331 | * 0: NULL, NULL - first new snapshot |
332 | * 1: snap_src, NULL - normal snapshot | |
333 | * 2: snap_src, snap_dest - waiting for handover | |
334 | * 2: snap_src, NULL - handed over, waiting for old to be deleted | |
335 | * 1: NULL, snap_dest - source got destroyed without handover | |
336 | */ | |
337 | static int __find_snapshots_sharing_cow(struct dm_snapshot *snap, | |
338 | struct dm_snapshot **snap_src, | |
9d3b15c4 MP |
339 | struct dm_snapshot **snap_dest, |
340 | struct dm_snapshot **snap_merge) | |
c1f0c183 MS |
341 | { |
342 | struct dm_snapshot *s; | |
343 | struct origin *o; | |
344 | int count = 0; | |
345 | int active; | |
346 | ||
347 | o = __lookup_origin(snap->origin->bdev); | |
348 | if (!o) | |
349 | goto out; | |
350 | ||
351 | list_for_each_entry(s, &o->snapshots, list) { | |
9d3b15c4 MP |
352 | if (dm_target_is_snapshot_merge(s->ti) && snap_merge) |
353 | *snap_merge = s; | |
c1f0c183 MS |
354 | if (!bdev_equal(s->cow->bdev, snap->cow->bdev)) |
355 | continue; | |
356 | ||
357 | down_read(&s->lock); | |
358 | active = s->active; | |
359 | up_read(&s->lock); | |
360 | ||
361 | if (active) { | |
362 | if (snap_src) | |
363 | *snap_src = s; | |
364 | } else if (snap_dest) | |
365 | *snap_dest = s; | |
366 | ||
367 | count++; | |
368 | } | |
369 | ||
370 | out: | |
371 | return count; | |
372 | } | |
373 | ||
374 | /* | |
375 | * On success, returns 1 if this snapshot is a handover destination, | |
376 | * otherwise returns 0. | |
377 | */ | |
378 | static int __validate_exception_handover(struct dm_snapshot *snap) | |
379 | { | |
380 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; | |
9d3b15c4 | 381 | struct dm_snapshot *snap_merge = NULL; |
c1f0c183 MS |
382 | |
383 | /* Does snapshot need exceptions handed over to it? */ | |
9d3b15c4 MP |
384 | if ((__find_snapshots_sharing_cow(snap, &snap_src, &snap_dest, |
385 | &snap_merge) == 2) || | |
c1f0c183 MS |
386 | snap_dest) { |
387 | snap->ti->error = "Snapshot cow pairing for exception " | |
388 | "table handover failed"; | |
389 | return -EINVAL; | |
390 | } | |
391 | ||
392 | /* | |
393 | * If no snap_src was found, snap cannot become a handover | |
394 | * destination. | |
395 | */ | |
396 | if (!snap_src) | |
397 | return 0; | |
398 | ||
9d3b15c4 MP |
399 | /* |
400 | * Non-snapshot-merge handover? | |
401 | */ | |
402 | if (!dm_target_is_snapshot_merge(snap->ti)) | |
403 | return 1; | |
404 | ||
405 | /* | |
406 | * Do not allow more than one merging snapshot. | |
407 | */ | |
408 | if (snap_merge) { | |
409 | snap->ti->error = "A snapshot is already merging."; | |
410 | return -EINVAL; | |
411 | } | |
412 | ||
1e03f97e MP |
413 | if (!snap_src->store->type->prepare_merge || |
414 | !snap_src->store->type->commit_merge) { | |
415 | snap->ti->error = "Snapshot exception store does not " | |
416 | "support snapshot-merge."; | |
417 | return -EINVAL; | |
418 | } | |
419 | ||
c1f0c183 MS |
420 | return 1; |
421 | } | |
422 | ||
423 | static void __insert_snapshot(struct origin *o, struct dm_snapshot *s) | |
424 | { | |
425 | struct dm_snapshot *l; | |
426 | ||
427 | /* Sort the list according to chunk size, largest-first smallest-last */ | |
428 | list_for_each_entry(l, &o->snapshots, list) | |
429 | if (l->store->chunk_size < s->store->chunk_size) | |
430 | break; | |
431 | list_add_tail(&s->list, &l->list); | |
432 | } | |
433 | ||
1da177e4 LT |
434 | /* |
435 | * Make a note of the snapshot and its origin so we can look it | |
436 | * up when the origin has a write on it. | |
c1f0c183 MS |
437 | * |
438 | * Also validate snapshot exception store handovers. | |
439 | * On success, returns 1 if this registration is a handover destination, | |
440 | * otherwise returns 0. | |
1da177e4 LT |
441 | */ |
442 | static int register_snapshot(struct dm_snapshot *snap) | |
443 | { | |
c1f0c183 | 444 | struct origin *o, *new_o = NULL; |
1da177e4 | 445 | struct block_device *bdev = snap->origin->bdev; |
c1f0c183 | 446 | int r = 0; |
1da177e4 | 447 | |
60c856c8 MP |
448 | new_o = kmalloc(sizeof(*new_o), GFP_KERNEL); |
449 | if (!new_o) | |
450 | return -ENOMEM; | |
451 | ||
1da177e4 | 452 | down_write(&_origins_lock); |
1da177e4 | 453 | |
c1f0c183 MS |
454 | r = __validate_exception_handover(snap); |
455 | if (r < 0) { | |
456 | kfree(new_o); | |
457 | goto out; | |
458 | } | |
459 | ||
460 | o = __lookup_origin(bdev); | |
60c856c8 MP |
461 | if (o) |
462 | kfree(new_o); | |
463 | else { | |
1da177e4 | 464 | /* New origin */ |
60c856c8 | 465 | o = new_o; |
1da177e4 LT |
466 | |
467 | /* Initialise the struct */ | |
468 | INIT_LIST_HEAD(&o->snapshots); | |
469 | o->bdev = bdev; | |
470 | ||
471 | __insert_origin(o); | |
472 | } | |
473 | ||
c1f0c183 MS |
474 | __insert_snapshot(o, snap); |
475 | ||
476 | out: | |
477 | up_write(&_origins_lock); | |
478 | ||
479 | return r; | |
480 | } | |
481 | ||
482 | /* | |
483 | * Move snapshot to correct place in list according to chunk size. | |
484 | */ | |
485 | static void reregister_snapshot(struct dm_snapshot *s) | |
486 | { | |
487 | struct block_device *bdev = s->origin->bdev; | |
488 | ||
489 | down_write(&_origins_lock); | |
490 | ||
491 | list_del(&s->list); | |
492 | __insert_snapshot(__lookup_origin(bdev), s); | |
1da177e4 LT |
493 | |
494 | up_write(&_origins_lock); | |
1da177e4 LT |
495 | } |
496 | ||
497 | static void unregister_snapshot(struct dm_snapshot *s) | |
498 | { | |
499 | struct origin *o; | |
500 | ||
501 | down_write(&_origins_lock); | |
502 | o = __lookup_origin(s->origin->bdev); | |
503 | ||
504 | list_del(&s->list); | |
c1f0c183 | 505 | if (o && list_empty(&o->snapshots)) { |
1da177e4 LT |
506 | list_del(&o->hash_list); |
507 | kfree(o); | |
508 | } | |
509 | ||
510 | up_write(&_origins_lock); | |
511 | } | |
512 | ||
513 | /* | |
514 | * Implementation of the exception hash tables. | |
d74f81f8 MB |
515 | * The lowest hash_shift bits of the chunk number are ignored, allowing |
516 | * some consecutive chunks to be grouped together. | |
1da177e4 | 517 | */ |
3510cb94 JB |
518 | static int dm_exception_table_init(struct dm_exception_table *et, |
519 | uint32_t size, unsigned hash_shift) | |
1da177e4 LT |
520 | { |
521 | unsigned int i; | |
522 | ||
d74f81f8 | 523 | et->hash_shift = hash_shift; |
1da177e4 LT |
524 | et->hash_mask = size - 1; |
525 | et->table = dm_vcalloc(size, sizeof(struct list_head)); | |
526 | if (!et->table) | |
527 | return -ENOMEM; | |
528 | ||
529 | for (i = 0; i < size; i++) | |
530 | INIT_LIST_HEAD(et->table + i); | |
531 | ||
532 | return 0; | |
533 | } | |
534 | ||
3510cb94 JB |
535 | static void dm_exception_table_exit(struct dm_exception_table *et, |
536 | struct kmem_cache *mem) | |
1da177e4 LT |
537 | { |
538 | struct list_head *slot; | |
1d4989c8 | 539 | struct dm_exception *ex, *next; |
1da177e4 LT |
540 | int i, size; |
541 | ||
542 | size = et->hash_mask + 1; | |
543 | for (i = 0; i < size; i++) { | |
544 | slot = et->table + i; | |
545 | ||
546 | list_for_each_entry_safe (ex, next, slot, hash_list) | |
547 | kmem_cache_free(mem, ex); | |
548 | } | |
549 | ||
550 | vfree(et->table); | |
551 | } | |
552 | ||
191437a5 | 553 | static uint32_t exception_hash(struct dm_exception_table *et, chunk_t chunk) |
1da177e4 | 554 | { |
d74f81f8 | 555 | return (chunk >> et->hash_shift) & et->hash_mask; |
1da177e4 LT |
556 | } |
557 | ||
3510cb94 | 558 | static void dm_remove_exception(struct dm_exception *e) |
1da177e4 LT |
559 | { |
560 | list_del(&e->hash_list); | |
561 | } | |
562 | ||
563 | /* | |
564 | * Return the exception data for a sector, or NULL if not | |
565 | * remapped. | |
566 | */ | |
3510cb94 JB |
567 | static struct dm_exception *dm_lookup_exception(struct dm_exception_table *et, |
568 | chunk_t chunk) | |
1da177e4 LT |
569 | { |
570 | struct list_head *slot; | |
1d4989c8 | 571 | struct dm_exception *e; |
1da177e4 LT |
572 | |
573 | slot = &et->table[exception_hash(et, chunk)]; | |
574 | list_for_each_entry (e, slot, hash_list) | |
d74f81f8 MB |
575 | if (chunk >= e->old_chunk && |
576 | chunk <= e->old_chunk + dm_consecutive_chunk_count(e)) | |
1da177e4 LT |
577 | return e; |
578 | ||
579 | return NULL; | |
580 | } | |
581 | ||
3510cb94 | 582 | static struct dm_exception *alloc_completed_exception(void) |
1da177e4 | 583 | { |
1d4989c8 | 584 | struct dm_exception *e; |
1da177e4 LT |
585 | |
586 | e = kmem_cache_alloc(exception_cache, GFP_NOIO); | |
587 | if (!e) | |
588 | e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); | |
589 | ||
590 | return e; | |
591 | } | |
592 | ||
3510cb94 | 593 | static void free_completed_exception(struct dm_exception *e) |
1da177e4 LT |
594 | { |
595 | kmem_cache_free(exception_cache, e); | |
596 | } | |
597 | ||
92e86812 | 598 | static struct dm_snap_pending_exception *alloc_pending_exception(struct dm_snapshot *s) |
1da177e4 | 599 | { |
92e86812 MP |
600 | struct dm_snap_pending_exception *pe = mempool_alloc(s->pending_pool, |
601 | GFP_NOIO); | |
602 | ||
879129d2 | 603 | atomic_inc(&s->pending_exceptions_count); |
92e86812 MP |
604 | pe->snap = s; |
605 | ||
606 | return pe; | |
1da177e4 LT |
607 | } |
608 | ||
028867ac | 609 | static void free_pending_exception(struct dm_snap_pending_exception *pe) |
1da177e4 | 610 | { |
879129d2 MP |
611 | struct dm_snapshot *s = pe->snap; |
612 | ||
613 | mempool_free(pe, s->pending_pool); | |
614 | smp_mb__before_atomic_dec(); | |
615 | atomic_dec(&s->pending_exceptions_count); | |
1da177e4 LT |
616 | } |
617 | ||
3510cb94 JB |
618 | static void dm_insert_exception(struct dm_exception_table *eh, |
619 | struct dm_exception *new_e) | |
d74f81f8 | 620 | { |
d74f81f8 | 621 | struct list_head *l; |
1d4989c8 | 622 | struct dm_exception *e = NULL; |
d74f81f8 MB |
623 | |
624 | l = &eh->table[exception_hash(eh, new_e->old_chunk)]; | |
625 | ||
626 | /* Add immediately if this table doesn't support consecutive chunks */ | |
627 | if (!eh->hash_shift) | |
628 | goto out; | |
629 | ||
630 | /* List is ordered by old_chunk */ | |
631 | list_for_each_entry_reverse(e, l, hash_list) { | |
632 | /* Insert after an existing chunk? */ | |
633 | if (new_e->old_chunk == (e->old_chunk + | |
634 | dm_consecutive_chunk_count(e) + 1) && | |
635 | new_e->new_chunk == (dm_chunk_number(e->new_chunk) + | |
636 | dm_consecutive_chunk_count(e) + 1)) { | |
637 | dm_consecutive_chunk_count_inc(e); | |
3510cb94 | 638 | free_completed_exception(new_e); |
d74f81f8 MB |
639 | return; |
640 | } | |
641 | ||
642 | /* Insert before an existing chunk? */ | |
643 | if (new_e->old_chunk == (e->old_chunk - 1) && | |
644 | new_e->new_chunk == (dm_chunk_number(e->new_chunk) - 1)) { | |
645 | dm_consecutive_chunk_count_inc(e); | |
646 | e->old_chunk--; | |
647 | e->new_chunk--; | |
3510cb94 | 648 | free_completed_exception(new_e); |
d74f81f8 MB |
649 | return; |
650 | } | |
651 | ||
652 | if (new_e->old_chunk > e->old_chunk) | |
653 | break; | |
654 | } | |
655 | ||
656 | out: | |
657 | list_add(&new_e->hash_list, e ? &e->hash_list : l); | |
658 | } | |
659 | ||
a159c1ac JB |
660 | /* |
661 | * Callback used by the exception stores to load exceptions when | |
662 | * initialising. | |
663 | */ | |
664 | static int dm_add_exception(void *context, chunk_t old, chunk_t new) | |
1da177e4 | 665 | { |
a159c1ac | 666 | struct dm_snapshot *s = context; |
1d4989c8 | 667 | struct dm_exception *e; |
1da177e4 | 668 | |
3510cb94 | 669 | e = alloc_completed_exception(); |
1da177e4 LT |
670 | if (!e) |
671 | return -ENOMEM; | |
672 | ||
673 | e->old_chunk = old; | |
d74f81f8 MB |
674 | |
675 | /* Consecutive_count is implicitly initialised to zero */ | |
1da177e4 | 676 | e->new_chunk = new; |
d74f81f8 | 677 | |
3510cb94 | 678 | dm_insert_exception(&s->complete, e); |
d74f81f8 | 679 | |
1da177e4 LT |
680 | return 0; |
681 | } | |
682 | ||
7e201b35 MP |
683 | /* |
684 | * Return a minimum chunk size of all snapshots that have the specified origin. | |
685 | * Return zero if the origin has no snapshots. | |
686 | */ | |
687 | static sector_t __minimum_chunk_size(struct origin *o) | |
688 | { | |
689 | struct dm_snapshot *snap; | |
690 | unsigned chunk_size = 0; | |
691 | ||
692 | if (o) | |
693 | list_for_each_entry(snap, &o->snapshots, list) | |
694 | chunk_size = min_not_zero(chunk_size, | |
695 | snap->store->chunk_size); | |
696 | ||
697 | return chunk_size; | |
698 | } | |
699 | ||
1da177e4 LT |
700 | /* |
701 | * Hard coded magic. | |
702 | */ | |
703 | static int calc_max_buckets(void) | |
704 | { | |
705 | /* use a fixed size of 2MB */ | |
706 | unsigned long mem = 2 * 1024 * 1024; | |
707 | mem /= sizeof(struct list_head); | |
708 | ||
709 | return mem; | |
710 | } | |
711 | ||
1da177e4 LT |
712 | /* |
713 | * Allocate room for a suitable hash table. | |
714 | */ | |
fee1998e | 715 | static int init_hash_tables(struct dm_snapshot *s) |
1da177e4 LT |
716 | { |
717 | sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; | |
718 | ||
719 | /* | |
720 | * Calculate based on the size of the original volume or | |
721 | * the COW volume... | |
722 | */ | |
fc56f6fb | 723 | cow_dev_size = get_dev_size(s->cow->bdev); |
1da177e4 LT |
724 | origin_dev_size = get_dev_size(s->origin->bdev); |
725 | max_buckets = calc_max_buckets(); | |
726 | ||
fee1998e | 727 | hash_size = min(origin_dev_size, cow_dev_size) >> s->store->chunk_shift; |
1da177e4 LT |
728 | hash_size = min(hash_size, max_buckets); |
729 | ||
8e87b9b8 MP |
730 | if (hash_size < 64) |
731 | hash_size = 64; | |
8defd830 | 732 | hash_size = rounddown_pow_of_two(hash_size); |
3510cb94 JB |
733 | if (dm_exception_table_init(&s->complete, hash_size, |
734 | DM_CHUNK_CONSECUTIVE_BITS)) | |
1da177e4 LT |
735 | return -ENOMEM; |
736 | ||
737 | /* | |
738 | * Allocate hash table for in-flight exceptions | |
739 | * Make this smaller than the real hash table | |
740 | */ | |
741 | hash_size >>= 3; | |
742 | if (hash_size < 64) | |
743 | hash_size = 64; | |
744 | ||
3510cb94 JB |
745 | if (dm_exception_table_init(&s->pending, hash_size, 0)) { |
746 | dm_exception_table_exit(&s->complete, exception_cache); | |
1da177e4 LT |
747 | return -ENOMEM; |
748 | } | |
749 | ||
750 | return 0; | |
751 | } | |
752 | ||
1e03f97e MP |
753 | static void merge_shutdown(struct dm_snapshot *s) |
754 | { | |
755 | clear_bit_unlock(RUNNING_MERGE, &s->state_bits); | |
756 | smp_mb__after_clear_bit(); | |
757 | wake_up_bit(&s->state_bits, RUNNING_MERGE); | |
758 | } | |
759 | ||
9fe86254 MP |
760 | static struct bio *__release_queued_bios_after_merge(struct dm_snapshot *s) |
761 | { | |
762 | s->first_merging_chunk = 0; | |
763 | s->num_merging_chunks = 0; | |
764 | ||
765 | return bio_list_get(&s->bios_queued_during_merge); | |
766 | } | |
767 | ||
1e03f97e MP |
768 | /* |
769 | * Remove one chunk from the index of completed exceptions. | |
770 | */ | |
771 | static int __remove_single_exception_chunk(struct dm_snapshot *s, | |
772 | chunk_t old_chunk) | |
773 | { | |
774 | struct dm_exception *e; | |
775 | ||
1e03f97e MP |
776 | e = dm_lookup_exception(&s->complete, old_chunk); |
777 | if (!e) { | |
778 | DMERR("Corruption detected: exception for block %llu is " | |
779 | "on disk but not in memory", | |
780 | (unsigned long long)old_chunk); | |
781 | return -EINVAL; | |
782 | } | |
783 | ||
784 | /* | |
785 | * If this is the only chunk using this exception, remove exception. | |
786 | */ | |
787 | if (!dm_consecutive_chunk_count(e)) { | |
788 | dm_remove_exception(e); | |
789 | free_completed_exception(e); | |
790 | return 0; | |
791 | } | |
792 | ||
793 | /* | |
794 | * The chunk may be either at the beginning or the end of a | |
795 | * group of consecutive chunks - never in the middle. We are | |
796 | * removing chunks in the opposite order to that in which they | |
797 | * were added, so this should always be true. | |
798 | * Decrement the consecutive chunk counter and adjust the | |
799 | * starting point if necessary. | |
800 | */ | |
801 | if (old_chunk == e->old_chunk) { | |
802 | e->old_chunk++; | |
803 | e->new_chunk++; | |
804 | } else if (old_chunk != e->old_chunk + | |
805 | dm_consecutive_chunk_count(e)) { | |
806 | DMERR("Attempt to merge block %llu from the " | |
807 | "middle of a chunk range [%llu - %llu]", | |
808 | (unsigned long long)old_chunk, | |
809 | (unsigned long long)e->old_chunk, | |
810 | (unsigned long long) | |
811 | e->old_chunk + dm_consecutive_chunk_count(e)); | |
812 | return -EINVAL; | |
813 | } | |
814 | ||
815 | dm_consecutive_chunk_count_dec(e); | |
816 | ||
817 | return 0; | |
818 | } | |
819 | ||
9fe86254 MP |
820 | static void flush_bios(struct bio *bio); |
821 | ||
822 | static int remove_single_exception_chunk(struct dm_snapshot *s) | |
1e03f97e | 823 | { |
9fe86254 MP |
824 | struct bio *b = NULL; |
825 | int r; | |
826 | chunk_t old_chunk = s->first_merging_chunk + s->num_merging_chunks - 1; | |
1e03f97e MP |
827 | |
828 | down_write(&s->lock); | |
9fe86254 MP |
829 | |
830 | /* | |
831 | * Process chunks (and associated exceptions) in reverse order | |
832 | * so that dm_consecutive_chunk_count_dec() accounting works. | |
833 | */ | |
834 | do { | |
835 | r = __remove_single_exception_chunk(s, old_chunk); | |
836 | if (r) | |
837 | goto out; | |
838 | } while (old_chunk-- > s->first_merging_chunk); | |
839 | ||
840 | b = __release_queued_bios_after_merge(s); | |
841 | ||
842 | out: | |
1e03f97e | 843 | up_write(&s->lock); |
9fe86254 MP |
844 | if (b) |
845 | flush_bios(b); | |
1e03f97e MP |
846 | |
847 | return r; | |
848 | } | |
849 | ||
73dfd078 MP |
850 | static int origin_write_extent(struct dm_snapshot *merging_snap, |
851 | sector_t sector, unsigned chunk_size); | |
852 | ||
1e03f97e MP |
853 | static void merge_callback(int read_err, unsigned long write_err, |
854 | void *context); | |
855 | ||
73dfd078 MP |
856 | static uint64_t read_pending_exceptions_done_count(void) |
857 | { | |
858 | uint64_t pending_exceptions_done; | |
859 | ||
860 | spin_lock(&_pending_exceptions_done_spinlock); | |
861 | pending_exceptions_done = _pending_exceptions_done_count; | |
862 | spin_unlock(&_pending_exceptions_done_spinlock); | |
863 | ||
864 | return pending_exceptions_done; | |
865 | } | |
866 | ||
867 | static void increment_pending_exceptions_done_count(void) | |
868 | { | |
869 | spin_lock(&_pending_exceptions_done_spinlock); | |
870 | _pending_exceptions_done_count++; | |
871 | spin_unlock(&_pending_exceptions_done_spinlock); | |
872 | ||
873 | wake_up_all(&_pending_exceptions_done); | |
874 | } | |
875 | ||
1e03f97e MP |
876 | static void snapshot_merge_next_chunks(struct dm_snapshot *s) |
877 | { | |
8a2d5286 | 878 | int i, linear_chunks; |
1e03f97e MP |
879 | chunk_t old_chunk, new_chunk; |
880 | struct dm_io_region src, dest; | |
8a2d5286 | 881 | sector_t io_size; |
73dfd078 | 882 | uint64_t previous_count; |
1e03f97e MP |
883 | |
884 | BUG_ON(!test_bit(RUNNING_MERGE, &s->state_bits)); | |
885 | if (unlikely(test_bit(SHUTDOWN_MERGE, &s->state_bits))) | |
886 | goto shut; | |
887 | ||
888 | /* | |
889 | * valid flag never changes during merge, so no lock required. | |
890 | */ | |
891 | if (!s->valid) { | |
892 | DMERR("Snapshot is invalid: can't merge"); | |
893 | goto shut; | |
894 | } | |
895 | ||
8a2d5286 MS |
896 | linear_chunks = s->store->type->prepare_merge(s->store, &old_chunk, |
897 | &new_chunk); | |
898 | if (linear_chunks <= 0) { | |
d8ddb1cf | 899 | if (linear_chunks < 0) { |
1e03f97e MP |
900 | DMERR("Read error in exception store: " |
901 | "shutting down merge"); | |
d8ddb1cf MS |
902 | down_write(&s->lock); |
903 | s->merge_failed = 1; | |
904 | up_write(&s->lock); | |
905 | } | |
1e03f97e MP |
906 | goto shut; |
907 | } | |
908 | ||
8a2d5286 MS |
909 | /* Adjust old_chunk and new_chunk to reflect start of linear region */ |
910 | old_chunk = old_chunk + 1 - linear_chunks; | |
911 | new_chunk = new_chunk + 1 - linear_chunks; | |
912 | ||
913 | /* | |
914 | * Use one (potentially large) I/O to copy all 'linear_chunks' | |
915 | * from the exception store to the origin | |
916 | */ | |
917 | io_size = linear_chunks * s->store->chunk_size; | |
1e03f97e | 918 | |
1e03f97e MP |
919 | dest.bdev = s->origin->bdev; |
920 | dest.sector = chunk_to_sector(s->store, old_chunk); | |
8a2d5286 | 921 | dest.count = min(io_size, get_dev_size(dest.bdev) - dest.sector); |
1e03f97e MP |
922 | |
923 | src.bdev = s->cow->bdev; | |
924 | src.sector = chunk_to_sector(s->store, new_chunk); | |
925 | src.count = dest.count; | |
926 | ||
73dfd078 MP |
927 | /* |
928 | * Reallocate any exceptions needed in other snapshots then | |
929 | * wait for the pending exceptions to complete. | |
930 | * Each time any pending exception (globally on the system) | |
931 | * completes we are woken and repeat the process to find out | |
932 | * if we can proceed. While this may not seem a particularly | |
933 | * efficient algorithm, it is not expected to have any | |
934 | * significant impact on performance. | |
935 | */ | |
936 | previous_count = read_pending_exceptions_done_count(); | |
8a2d5286 | 937 | while (origin_write_extent(s, dest.sector, io_size)) { |
73dfd078 MP |
938 | wait_event(_pending_exceptions_done, |
939 | (read_pending_exceptions_done_count() != | |
940 | previous_count)); | |
941 | /* Retry after the wait, until all exceptions are done. */ | |
942 | previous_count = read_pending_exceptions_done_count(); | |
943 | } | |
944 | ||
9fe86254 MP |
945 | down_write(&s->lock); |
946 | s->first_merging_chunk = old_chunk; | |
8a2d5286 | 947 | s->num_merging_chunks = linear_chunks; |
9fe86254 MP |
948 | up_write(&s->lock); |
949 | ||
8a2d5286 MS |
950 | /* Wait until writes to all 'linear_chunks' drain */ |
951 | for (i = 0; i < linear_chunks; i++) | |
952 | __check_for_conflicting_io(s, old_chunk + i); | |
9fe86254 | 953 | |
1e03f97e MP |
954 | dm_kcopyd_copy(s->kcopyd_client, &src, 1, &dest, 0, merge_callback, s); |
955 | return; | |
956 | ||
957 | shut: | |
958 | merge_shutdown(s); | |
959 | } | |
960 | ||
9fe86254 MP |
961 | static void error_bios(struct bio *bio); |
962 | ||
1e03f97e MP |
963 | static void merge_callback(int read_err, unsigned long write_err, void *context) |
964 | { | |
965 | struct dm_snapshot *s = context; | |
9fe86254 | 966 | struct bio *b = NULL; |
1e03f97e MP |
967 | |
968 | if (read_err || write_err) { | |
969 | if (read_err) | |
970 | DMERR("Read error: shutting down merge."); | |
971 | else | |
972 | DMERR("Write error: shutting down merge."); | |
973 | goto shut; | |
974 | } | |
975 | ||
9fe86254 MP |
976 | if (s->store->type->commit_merge(s->store, |
977 | s->num_merging_chunks) < 0) { | |
1e03f97e MP |
978 | DMERR("Write error in exception store: shutting down merge"); |
979 | goto shut; | |
980 | } | |
981 | ||
9fe86254 MP |
982 | if (remove_single_exception_chunk(s) < 0) |
983 | goto shut; | |
984 | ||
1e03f97e MP |
985 | snapshot_merge_next_chunks(s); |
986 | ||
987 | return; | |
988 | ||
989 | shut: | |
9fe86254 | 990 | down_write(&s->lock); |
d8ddb1cf | 991 | s->merge_failed = 1; |
9fe86254 MP |
992 | b = __release_queued_bios_after_merge(s); |
993 | up_write(&s->lock); | |
994 | error_bios(b); | |
995 | ||
1e03f97e MP |
996 | merge_shutdown(s); |
997 | } | |
998 | ||
999 | static void start_merge(struct dm_snapshot *s) | |
1000 | { | |
1001 | if (!test_and_set_bit(RUNNING_MERGE, &s->state_bits)) | |
1002 | snapshot_merge_next_chunks(s); | |
1003 | } | |
1004 | ||
1005 | static int wait_schedule(void *ptr) | |
1006 | { | |
1007 | schedule(); | |
1008 | ||
1009 | return 0; | |
1010 | } | |
1011 | ||
1012 | /* | |
1013 | * Stop the merging process and wait until it finishes. | |
1014 | */ | |
1015 | static void stop_merge(struct dm_snapshot *s) | |
1016 | { | |
1017 | set_bit(SHUTDOWN_MERGE, &s->state_bits); | |
1018 | wait_on_bit(&s->state_bits, RUNNING_MERGE, wait_schedule, | |
1019 | TASK_UNINTERRUPTIBLE); | |
1020 | clear_bit(SHUTDOWN_MERGE, &s->state_bits); | |
1021 | } | |
1022 | ||
1da177e4 LT |
1023 | /* |
1024 | * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> | |
1025 | */ | |
1026 | static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
1027 | { | |
1028 | struct dm_snapshot *s; | |
cd45daff | 1029 | int i; |
1da177e4 | 1030 | int r = -EINVAL; |
fc56f6fb | 1031 | char *origin_path, *cow_path; |
10b8106a MS |
1032 | unsigned args_used, num_flush_requests = 1; |
1033 | fmode_t origin_mode = FMODE_READ; | |
1da177e4 | 1034 | |
4c7e3bf4 | 1035 | if (argc != 4) { |
72d94861 | 1036 | ti->error = "requires exactly 4 arguments"; |
1da177e4 | 1037 | r = -EINVAL; |
fc56f6fb | 1038 | goto bad; |
1da177e4 LT |
1039 | } |
1040 | ||
10b8106a MS |
1041 | if (dm_target_is_snapshot_merge(ti)) { |
1042 | num_flush_requests = 2; | |
1043 | origin_mode = FMODE_WRITE; | |
1044 | } | |
1045 | ||
fc56f6fb MS |
1046 | s = kmalloc(sizeof(*s), GFP_KERNEL); |
1047 | if (!s) { | |
1048 | ti->error = "Cannot allocate snapshot context private " | |
1049 | "structure"; | |
1050 | r = -ENOMEM; | |
1051 | goto bad; | |
1052 | } | |
1053 | ||
c2411045 MP |
1054 | origin_path = argv[0]; |
1055 | argv++; | |
1056 | argc--; | |
1057 | ||
1058 | r = dm_get_device(ti, origin_path, origin_mode, &s->origin); | |
1059 | if (r) { | |
1060 | ti->error = "Cannot get origin device"; | |
1061 | goto bad_origin; | |
1062 | } | |
1063 | ||
fc56f6fb MS |
1064 | cow_path = argv[0]; |
1065 | argv++; | |
1066 | argc--; | |
1067 | ||
024d37e9 | 1068 | r = dm_get_device(ti, cow_path, dm_table_get_mode(ti->table), &s->cow); |
fc56f6fb MS |
1069 | if (r) { |
1070 | ti->error = "Cannot get COW device"; | |
1071 | goto bad_cow; | |
1072 | } | |
1073 | ||
1074 | r = dm_exception_store_create(ti, argc, argv, s, &args_used, &s->store); | |
fee1998e JB |
1075 | if (r) { |
1076 | ti->error = "Couldn't create exception store"; | |
1da177e4 | 1077 | r = -EINVAL; |
fc56f6fb | 1078 | goto bad_store; |
1da177e4 LT |
1079 | } |
1080 | ||
fee1998e JB |
1081 | argv += args_used; |
1082 | argc -= args_used; | |
1083 | ||
fc56f6fb | 1084 | s->ti = ti; |
1da177e4 | 1085 | s->valid = 1; |
aa14edeb | 1086 | s->active = 0; |
879129d2 | 1087 | atomic_set(&s->pending_exceptions_count, 0); |
1da177e4 | 1088 | init_rwsem(&s->lock); |
c1f0c183 | 1089 | INIT_LIST_HEAD(&s->list); |
ca3a931f | 1090 | spin_lock_init(&s->pe_lock); |
1e03f97e | 1091 | s->state_bits = 0; |
d8ddb1cf | 1092 | s->merge_failed = 0; |
9fe86254 MP |
1093 | s->first_merging_chunk = 0; |
1094 | s->num_merging_chunks = 0; | |
1095 | bio_list_init(&s->bios_queued_during_merge); | |
1da177e4 LT |
1096 | |
1097 | /* Allocate hash table for COW data */ | |
fee1998e | 1098 | if (init_hash_tables(s)) { |
1da177e4 LT |
1099 | ti->error = "Unable to allocate hash table space"; |
1100 | r = -ENOMEM; | |
fee1998e | 1101 | goto bad_hash_tables; |
1da177e4 LT |
1102 | } |
1103 | ||
fa34ce73 MP |
1104 | s->kcopyd_client = dm_kcopyd_client_create(); |
1105 | if (IS_ERR(s->kcopyd_client)) { | |
1106 | r = PTR_ERR(s->kcopyd_client); | |
1da177e4 | 1107 | ti->error = "Could not create kcopyd client"; |
fee1998e | 1108 | goto bad_kcopyd; |
1da177e4 LT |
1109 | } |
1110 | ||
92e86812 MP |
1111 | s->pending_pool = mempool_create_slab_pool(MIN_IOS, pending_cache); |
1112 | if (!s->pending_pool) { | |
1113 | ti->error = "Could not allocate mempool for pending exceptions"; | |
fee1998e | 1114 | goto bad_pending_pool; |
92e86812 MP |
1115 | } |
1116 | ||
cd45daff MP |
1117 | s->tracked_chunk_pool = mempool_create_slab_pool(MIN_IOS, |
1118 | tracked_chunk_cache); | |
1119 | if (!s->tracked_chunk_pool) { | |
1120 | ti->error = "Could not allocate tracked_chunk mempool for " | |
1121 | "tracking reads"; | |
92e86812 | 1122 | goto bad_tracked_chunk_pool; |
cd45daff MP |
1123 | } |
1124 | ||
1125 | for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) | |
1126 | INIT_HLIST_HEAD(&s->tracked_chunk_hash[i]); | |
1127 | ||
1128 | spin_lock_init(&s->tracked_chunk_lock); | |
1129 | ||
c1f0c183 | 1130 | ti->private = s; |
10b8106a | 1131 | ti->num_flush_requests = num_flush_requests; |
c1f0c183 MS |
1132 | |
1133 | /* Add snapshot to the list of snapshots for this origin */ | |
1134 | /* Exceptions aren't triggered till snapshot_resume() is called */ | |
1135 | r = register_snapshot(s); | |
1136 | if (r == -ENOMEM) { | |
1137 | ti->error = "Snapshot origin struct allocation failed"; | |
1138 | goto bad_load_and_register; | |
1139 | } else if (r < 0) { | |
1140 | /* invalid handover, register_snapshot has set ti->error */ | |
1141 | goto bad_load_and_register; | |
1142 | } | |
1143 | ||
1144 | /* | |
1145 | * Metadata must only be loaded into one table at once, so skip this | |
1146 | * if metadata will be handed over during resume. | |
1147 | * Chunk size will be set during the handover - set it to zero to | |
1148 | * ensure it's ignored. | |
1149 | */ | |
1150 | if (r > 0) { | |
1151 | s->store->chunk_size = 0; | |
1152 | return 0; | |
1153 | } | |
1154 | ||
493df71c JB |
1155 | r = s->store->type->read_metadata(s->store, dm_add_exception, |
1156 | (void *)s); | |
0764147b | 1157 | if (r < 0) { |
f9cea4f7 | 1158 | ti->error = "Failed to read snapshot metadata"; |
c1f0c183 | 1159 | goto bad_read_metadata; |
0764147b MB |
1160 | } else if (r > 0) { |
1161 | s->valid = 0; | |
1162 | DMWARN("Snapshot is marked invalid."); | |
f9cea4f7 | 1163 | } |
aa14edeb | 1164 | |
3f2412dc MP |
1165 | if (!s->store->chunk_size) { |
1166 | ti->error = "Chunk size not set"; | |
c1f0c183 | 1167 | goto bad_read_metadata; |
1da177e4 | 1168 | } |
d0216849 | 1169 | ti->split_io = s->store->chunk_size; |
1da177e4 LT |
1170 | |
1171 | return 0; | |
1172 | ||
c1f0c183 MS |
1173 | bad_read_metadata: |
1174 | unregister_snapshot(s); | |
1175 | ||
fee1998e | 1176 | bad_load_and_register: |
cd45daff MP |
1177 | mempool_destroy(s->tracked_chunk_pool); |
1178 | ||
fee1998e | 1179 | bad_tracked_chunk_pool: |
92e86812 MP |
1180 | mempool_destroy(s->pending_pool); |
1181 | ||
fee1998e | 1182 | bad_pending_pool: |
eb69aca5 | 1183 | dm_kcopyd_client_destroy(s->kcopyd_client); |
1da177e4 | 1184 | |
fee1998e | 1185 | bad_kcopyd: |
3510cb94 JB |
1186 | dm_exception_table_exit(&s->pending, pending_cache); |
1187 | dm_exception_table_exit(&s->complete, exception_cache); | |
1da177e4 | 1188 | |
fee1998e | 1189 | bad_hash_tables: |
fc56f6fb | 1190 | dm_exception_store_destroy(s->store); |
1da177e4 | 1191 | |
fc56f6fb MS |
1192 | bad_store: |
1193 | dm_put_device(ti, s->cow); | |
fee1998e | 1194 | |
fc56f6fb | 1195 | bad_cow: |
c2411045 MP |
1196 | dm_put_device(ti, s->origin); |
1197 | ||
1198 | bad_origin: | |
fc56f6fb MS |
1199 | kfree(s); |
1200 | ||
1201 | bad: | |
1da177e4 LT |
1202 | return r; |
1203 | } | |
1204 | ||
31c93a0c MB |
1205 | static void __free_exceptions(struct dm_snapshot *s) |
1206 | { | |
eb69aca5 | 1207 | dm_kcopyd_client_destroy(s->kcopyd_client); |
31c93a0c MB |
1208 | s->kcopyd_client = NULL; |
1209 | ||
3510cb94 JB |
1210 | dm_exception_table_exit(&s->pending, pending_cache); |
1211 | dm_exception_table_exit(&s->complete, exception_cache); | |
31c93a0c MB |
1212 | } |
1213 | ||
c1f0c183 MS |
1214 | static void __handover_exceptions(struct dm_snapshot *snap_src, |
1215 | struct dm_snapshot *snap_dest) | |
1216 | { | |
1217 | union { | |
1218 | struct dm_exception_table table_swap; | |
1219 | struct dm_exception_store *store_swap; | |
1220 | } u; | |
1221 | ||
1222 | /* | |
1223 | * Swap all snapshot context information between the two instances. | |
1224 | */ | |
1225 | u.table_swap = snap_dest->complete; | |
1226 | snap_dest->complete = snap_src->complete; | |
1227 | snap_src->complete = u.table_swap; | |
1228 | ||
1229 | u.store_swap = snap_dest->store; | |
1230 | snap_dest->store = snap_src->store; | |
1231 | snap_src->store = u.store_swap; | |
1232 | ||
1233 | snap_dest->store->snap = snap_dest; | |
1234 | snap_src->store->snap = snap_src; | |
1235 | ||
1236 | snap_dest->ti->split_io = snap_dest->store->chunk_size; | |
1237 | snap_dest->valid = snap_src->valid; | |
1238 | ||
1239 | /* | |
1240 | * Set source invalid to ensure it receives no further I/O. | |
1241 | */ | |
1242 | snap_src->valid = 0; | |
1243 | } | |
1244 | ||
1da177e4 LT |
1245 | static void snapshot_dtr(struct dm_target *ti) |
1246 | { | |
cd45daff MP |
1247 | #ifdef CONFIG_DM_DEBUG |
1248 | int i; | |
1249 | #endif | |
028867ac | 1250 | struct dm_snapshot *s = ti->private; |
c1f0c183 | 1251 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; |
1da177e4 | 1252 | |
c1f0c183 MS |
1253 | down_read(&_origins_lock); |
1254 | /* Check whether exception handover must be cancelled */ | |
9d3b15c4 | 1255 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1256 | if (snap_src && snap_dest && (s == snap_src)) { |
1257 | down_write(&snap_dest->lock); | |
1258 | snap_dest->valid = 0; | |
1259 | up_write(&snap_dest->lock); | |
1260 | DMERR("Cancelling snapshot handover."); | |
1261 | } | |
1262 | up_read(&_origins_lock); | |
1263 | ||
1e03f97e MP |
1264 | if (dm_target_is_snapshot_merge(ti)) |
1265 | stop_merge(s); | |
1266 | ||
138728dc AK |
1267 | /* Prevent further origin writes from using this snapshot. */ |
1268 | /* After this returns there can be no new kcopyd jobs. */ | |
1da177e4 LT |
1269 | unregister_snapshot(s); |
1270 | ||
879129d2 | 1271 | while (atomic_read(&s->pending_exceptions_count)) |
90fa1527 | 1272 | msleep(1); |
879129d2 MP |
1273 | /* |
1274 | * Ensure instructions in mempool_destroy aren't reordered | |
1275 | * before atomic_read. | |
1276 | */ | |
1277 | smp_mb(); | |
1278 | ||
cd45daff MP |
1279 | #ifdef CONFIG_DM_DEBUG |
1280 | for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) | |
1281 | BUG_ON(!hlist_empty(&s->tracked_chunk_hash[i])); | |
1282 | #endif | |
1283 | ||
1284 | mempool_destroy(s->tracked_chunk_pool); | |
1285 | ||
31c93a0c | 1286 | __free_exceptions(s); |
1da177e4 | 1287 | |
92e86812 MP |
1288 | mempool_destroy(s->pending_pool); |
1289 | ||
fee1998e | 1290 | dm_exception_store_destroy(s->store); |
138728dc | 1291 | |
fc56f6fb MS |
1292 | dm_put_device(ti, s->cow); |
1293 | ||
c2411045 MP |
1294 | dm_put_device(ti, s->origin); |
1295 | ||
1da177e4 LT |
1296 | kfree(s); |
1297 | } | |
1298 | ||
1299 | /* | |
1300 | * Flush a list of buffers. | |
1301 | */ | |
1302 | static void flush_bios(struct bio *bio) | |
1303 | { | |
1304 | struct bio *n; | |
1305 | ||
1306 | while (bio) { | |
1307 | n = bio->bi_next; | |
1308 | bio->bi_next = NULL; | |
1309 | generic_make_request(bio); | |
1310 | bio = n; | |
1311 | } | |
1312 | } | |
1313 | ||
515ad66c MP |
1314 | static int do_origin(struct dm_dev *origin, struct bio *bio); |
1315 | ||
1316 | /* | |
1317 | * Flush a list of buffers. | |
1318 | */ | |
1319 | static void retry_origin_bios(struct dm_snapshot *s, struct bio *bio) | |
1320 | { | |
1321 | struct bio *n; | |
1322 | int r; | |
1323 | ||
1324 | while (bio) { | |
1325 | n = bio->bi_next; | |
1326 | bio->bi_next = NULL; | |
1327 | r = do_origin(s->origin, bio); | |
1328 | if (r == DM_MAPIO_REMAPPED) | |
1329 | generic_make_request(bio); | |
1330 | bio = n; | |
1331 | } | |
1332 | } | |
1333 | ||
1da177e4 LT |
1334 | /* |
1335 | * Error a list of buffers. | |
1336 | */ | |
1337 | static void error_bios(struct bio *bio) | |
1338 | { | |
1339 | struct bio *n; | |
1340 | ||
1341 | while (bio) { | |
1342 | n = bio->bi_next; | |
1343 | bio->bi_next = NULL; | |
6712ecf8 | 1344 | bio_io_error(bio); |
1da177e4 LT |
1345 | bio = n; |
1346 | } | |
1347 | } | |
1348 | ||
695368ac | 1349 | static void __invalidate_snapshot(struct dm_snapshot *s, int err) |
76df1c65 AK |
1350 | { |
1351 | if (!s->valid) | |
1352 | return; | |
1353 | ||
1354 | if (err == -EIO) | |
1355 | DMERR("Invalidating snapshot: Error reading/writing."); | |
1356 | else if (err == -ENOMEM) | |
1357 | DMERR("Invalidating snapshot: Unable to allocate exception."); | |
1358 | ||
493df71c JB |
1359 | if (s->store->type->drop_snapshot) |
1360 | s->store->type->drop_snapshot(s->store); | |
76df1c65 AK |
1361 | |
1362 | s->valid = 0; | |
1363 | ||
fc56f6fb | 1364 | dm_table_event(s->ti->table); |
76df1c65 AK |
1365 | } |
1366 | ||
028867ac | 1367 | static void pending_complete(struct dm_snap_pending_exception *pe, int success) |
1da177e4 | 1368 | { |
1d4989c8 | 1369 | struct dm_exception *e; |
1da177e4 | 1370 | struct dm_snapshot *s = pe->snap; |
9d493fa8 AK |
1371 | struct bio *origin_bios = NULL; |
1372 | struct bio *snapshot_bios = NULL; | |
1373 | int error = 0; | |
1da177e4 | 1374 | |
76df1c65 AK |
1375 | if (!success) { |
1376 | /* Read/write error - snapshot is unusable */ | |
1da177e4 | 1377 | down_write(&s->lock); |
695368ac | 1378 | __invalidate_snapshot(s, -EIO); |
9d493fa8 | 1379 | error = 1; |
76df1c65 AK |
1380 | goto out; |
1381 | } | |
1382 | ||
3510cb94 | 1383 | e = alloc_completed_exception(); |
76df1c65 | 1384 | if (!e) { |
1da177e4 | 1385 | down_write(&s->lock); |
695368ac | 1386 | __invalidate_snapshot(s, -ENOMEM); |
9d493fa8 | 1387 | error = 1; |
76df1c65 AK |
1388 | goto out; |
1389 | } | |
1390 | *e = pe->e; | |
1da177e4 | 1391 | |
76df1c65 AK |
1392 | down_write(&s->lock); |
1393 | if (!s->valid) { | |
3510cb94 | 1394 | free_completed_exception(e); |
9d493fa8 | 1395 | error = 1; |
76df1c65 | 1396 | goto out; |
1da177e4 LT |
1397 | } |
1398 | ||
615d1eb9 MS |
1399 | /* Check for conflicting reads */ |
1400 | __check_for_conflicting_io(s, pe->e.old_chunk); | |
a8d41b59 | 1401 | |
9d493fa8 AK |
1402 | /* |
1403 | * Add a proper exception, and remove the | |
1404 | * in-flight exception from the list. | |
1405 | */ | |
3510cb94 | 1406 | dm_insert_exception(&s->complete, e); |
76df1c65 | 1407 | |
1da177e4 | 1408 | out: |
3510cb94 | 1409 | dm_remove_exception(&pe->e); |
9d493fa8 | 1410 | snapshot_bios = bio_list_get(&pe->snapshot_bios); |
515ad66c MP |
1411 | origin_bios = bio_list_get(&pe->origin_bios); |
1412 | free_pending_exception(pe); | |
1da177e4 | 1413 | |
73dfd078 MP |
1414 | increment_pending_exceptions_done_count(); |
1415 | ||
9d493fa8 AK |
1416 | up_write(&s->lock); |
1417 | ||
1418 | /* Submit any pending write bios */ | |
1419 | if (error) | |
1420 | error_bios(snapshot_bios); | |
1421 | else | |
1422 | flush_bios(snapshot_bios); | |
1423 | ||
515ad66c | 1424 | retry_origin_bios(s, origin_bios); |
1da177e4 LT |
1425 | } |
1426 | ||
1427 | static void commit_callback(void *context, int success) | |
1428 | { | |
028867ac AK |
1429 | struct dm_snap_pending_exception *pe = context; |
1430 | ||
1da177e4 LT |
1431 | pending_complete(pe, success); |
1432 | } | |
1433 | ||
1434 | /* | |
1435 | * Called when the copy I/O has finished. kcopyd actually runs | |
1436 | * this code so don't block. | |
1437 | */ | |
4cdc1d1f | 1438 | static void copy_callback(int read_err, unsigned long write_err, void *context) |
1da177e4 | 1439 | { |
028867ac | 1440 | struct dm_snap_pending_exception *pe = context; |
1da177e4 LT |
1441 | struct dm_snapshot *s = pe->snap; |
1442 | ||
1443 | if (read_err || write_err) | |
1444 | pending_complete(pe, 0); | |
1445 | ||
1446 | else | |
1447 | /* Update the metadata if we are persistent */ | |
493df71c JB |
1448 | s->store->type->commit_exception(s->store, &pe->e, |
1449 | commit_callback, pe); | |
1da177e4 LT |
1450 | } |
1451 | ||
1452 | /* | |
1453 | * Dispatches the copy operation to kcopyd. | |
1454 | */ | |
028867ac | 1455 | static void start_copy(struct dm_snap_pending_exception *pe) |
1da177e4 LT |
1456 | { |
1457 | struct dm_snapshot *s = pe->snap; | |
22a1ceb1 | 1458 | struct dm_io_region src, dest; |
1da177e4 LT |
1459 | struct block_device *bdev = s->origin->bdev; |
1460 | sector_t dev_size; | |
1461 | ||
1462 | dev_size = get_dev_size(bdev); | |
1463 | ||
1464 | src.bdev = bdev; | |
71fab00a | 1465 | src.sector = chunk_to_sector(s->store, pe->e.old_chunk); |
df96eee6 | 1466 | src.count = min((sector_t)s->store->chunk_size, dev_size - src.sector); |
1da177e4 | 1467 | |
fc56f6fb | 1468 | dest.bdev = s->cow->bdev; |
71fab00a | 1469 | dest.sector = chunk_to_sector(s->store, pe->e.new_chunk); |
1da177e4 LT |
1470 | dest.count = src.count; |
1471 | ||
1472 | /* Hand over to kcopyd */ | |
eb69aca5 | 1473 | dm_kcopyd_copy(s->kcopyd_client, |
1da177e4 LT |
1474 | &src, 1, &dest, 0, copy_callback, pe); |
1475 | } | |
1476 | ||
2913808e MP |
1477 | static struct dm_snap_pending_exception * |
1478 | __lookup_pending_exception(struct dm_snapshot *s, chunk_t chunk) | |
1479 | { | |
3510cb94 | 1480 | struct dm_exception *e = dm_lookup_exception(&s->pending, chunk); |
2913808e MP |
1481 | |
1482 | if (!e) | |
1483 | return NULL; | |
1484 | ||
1485 | return container_of(e, struct dm_snap_pending_exception, e); | |
1486 | } | |
1487 | ||
1da177e4 LT |
1488 | /* |
1489 | * Looks to see if this snapshot already has a pending exception | |
1490 | * for this chunk, otherwise it allocates a new one and inserts | |
1491 | * it into the pending table. | |
1492 | * | |
1493 | * NOTE: a write lock must be held on snap->lock before calling | |
1494 | * this. | |
1495 | */ | |
028867ac | 1496 | static struct dm_snap_pending_exception * |
c6621392 MP |
1497 | __find_pending_exception(struct dm_snapshot *s, |
1498 | struct dm_snap_pending_exception *pe, chunk_t chunk) | |
1da177e4 | 1499 | { |
c6621392 | 1500 | struct dm_snap_pending_exception *pe2; |
1da177e4 | 1501 | |
2913808e MP |
1502 | pe2 = __lookup_pending_exception(s, chunk); |
1503 | if (pe2) { | |
76df1c65 | 1504 | free_pending_exception(pe); |
2913808e | 1505 | return pe2; |
1da177e4 LT |
1506 | } |
1507 | ||
76df1c65 AK |
1508 | pe->e.old_chunk = chunk; |
1509 | bio_list_init(&pe->origin_bios); | |
1510 | bio_list_init(&pe->snapshot_bios); | |
76df1c65 AK |
1511 | pe->started = 0; |
1512 | ||
493df71c | 1513 | if (s->store->type->prepare_exception(s->store, &pe->e)) { |
76df1c65 AK |
1514 | free_pending_exception(pe); |
1515 | return NULL; | |
1516 | } | |
1517 | ||
3510cb94 | 1518 | dm_insert_exception(&s->pending, &pe->e); |
76df1c65 | 1519 | |
1da177e4 LT |
1520 | return pe; |
1521 | } | |
1522 | ||
1d4989c8 | 1523 | static void remap_exception(struct dm_snapshot *s, struct dm_exception *e, |
d74f81f8 | 1524 | struct bio *bio, chunk_t chunk) |
1da177e4 | 1525 | { |
fc56f6fb | 1526 | bio->bi_bdev = s->cow->bdev; |
71fab00a JB |
1527 | bio->bi_sector = chunk_to_sector(s->store, |
1528 | dm_chunk_number(e->new_chunk) + | |
1529 | (chunk - e->old_chunk)) + | |
1530 | (bio->bi_sector & | |
1531 | s->store->chunk_mask); | |
1da177e4 LT |
1532 | } |
1533 | ||
1534 | static int snapshot_map(struct dm_target *ti, struct bio *bio, | |
1535 | union map_info *map_context) | |
1536 | { | |
1d4989c8 | 1537 | struct dm_exception *e; |
028867ac | 1538 | struct dm_snapshot *s = ti->private; |
d2a7ad29 | 1539 | int r = DM_MAPIO_REMAPPED; |
1da177e4 | 1540 | chunk_t chunk; |
028867ac | 1541 | struct dm_snap_pending_exception *pe = NULL; |
1da177e4 | 1542 | |
d87f4c14 | 1543 | if (bio->bi_rw & REQ_FLUSH) { |
fc56f6fb | 1544 | bio->bi_bdev = s->cow->bdev; |
494b3ee7 MP |
1545 | return DM_MAPIO_REMAPPED; |
1546 | } | |
1547 | ||
71fab00a | 1548 | chunk = sector_to_chunk(s->store, bio->bi_sector); |
1da177e4 LT |
1549 | |
1550 | /* Full snapshots are not usable */ | |
76df1c65 | 1551 | /* To get here the table must be live so s->active is always set. */ |
1da177e4 | 1552 | if (!s->valid) |
f6a80ea8 | 1553 | return -EIO; |
1da177e4 | 1554 | |
ba40a2aa AK |
1555 | /* FIXME: should only take write lock if we need |
1556 | * to copy an exception */ | |
1557 | down_write(&s->lock); | |
1558 | ||
1559 | if (!s->valid) { | |
1560 | r = -EIO; | |
1561 | goto out_unlock; | |
1562 | } | |
1563 | ||
1564 | /* If the block is already remapped - use that, else remap it */ | |
3510cb94 | 1565 | e = dm_lookup_exception(&s->complete, chunk); |
ba40a2aa | 1566 | if (e) { |
d74f81f8 | 1567 | remap_exception(s, e, bio, chunk); |
ba40a2aa AK |
1568 | goto out_unlock; |
1569 | } | |
1570 | ||
1da177e4 LT |
1571 | /* |
1572 | * Write to snapshot - higher level takes care of RW/RO | |
1573 | * flags so we should only get this if we are | |
1574 | * writeable. | |
1575 | */ | |
1576 | if (bio_rw(bio) == WRITE) { | |
2913808e | 1577 | pe = __lookup_pending_exception(s, chunk); |
76df1c65 | 1578 | if (!pe) { |
c6621392 MP |
1579 | up_write(&s->lock); |
1580 | pe = alloc_pending_exception(s); | |
1581 | down_write(&s->lock); | |
1582 | ||
1583 | if (!s->valid) { | |
1584 | free_pending_exception(pe); | |
1585 | r = -EIO; | |
1586 | goto out_unlock; | |
1587 | } | |
1588 | ||
3510cb94 | 1589 | e = dm_lookup_exception(&s->complete, chunk); |
35bf659b MP |
1590 | if (e) { |
1591 | free_pending_exception(pe); | |
1592 | remap_exception(s, e, bio, chunk); | |
1593 | goto out_unlock; | |
1594 | } | |
1595 | ||
c6621392 | 1596 | pe = __find_pending_exception(s, pe, chunk); |
2913808e MP |
1597 | if (!pe) { |
1598 | __invalidate_snapshot(s, -ENOMEM); | |
1599 | r = -EIO; | |
1600 | goto out_unlock; | |
1601 | } | |
1da177e4 LT |
1602 | } |
1603 | ||
d74f81f8 | 1604 | remap_exception(s, &pe->e, bio, chunk); |
76df1c65 AK |
1605 | bio_list_add(&pe->snapshot_bios, bio); |
1606 | ||
d2a7ad29 | 1607 | r = DM_MAPIO_SUBMITTED; |
ba40a2aa | 1608 | |
76df1c65 AK |
1609 | if (!pe->started) { |
1610 | /* this is protected by snap->lock */ | |
1611 | pe->started = 1; | |
ba40a2aa | 1612 | up_write(&s->lock); |
76df1c65 | 1613 | start_copy(pe); |
ba40a2aa AK |
1614 | goto out; |
1615 | } | |
cd45daff | 1616 | } else { |
ba40a2aa | 1617 | bio->bi_bdev = s->origin->bdev; |
cd45daff MP |
1618 | map_context->ptr = track_chunk(s, chunk); |
1619 | } | |
1da177e4 | 1620 | |
ba40a2aa AK |
1621 | out_unlock: |
1622 | up_write(&s->lock); | |
1623 | out: | |
1da177e4 LT |
1624 | return r; |
1625 | } | |
1626 | ||
3452c2a1 MP |
1627 | /* |
1628 | * A snapshot-merge target behaves like a combination of a snapshot | |
1629 | * target and a snapshot-origin target. It only generates new | |
1630 | * exceptions in other snapshots and not in the one that is being | |
1631 | * merged. | |
1632 | * | |
1633 | * For each chunk, if there is an existing exception, it is used to | |
1634 | * redirect I/O to the cow device. Otherwise I/O is sent to the origin, | |
1635 | * which in turn might generate exceptions in other snapshots. | |
9fe86254 MP |
1636 | * If merging is currently taking place on the chunk in question, the |
1637 | * I/O is deferred by adding it to s->bios_queued_during_merge. | |
3452c2a1 MP |
1638 | */ |
1639 | static int snapshot_merge_map(struct dm_target *ti, struct bio *bio, | |
1640 | union map_info *map_context) | |
1641 | { | |
1642 | struct dm_exception *e; | |
1643 | struct dm_snapshot *s = ti->private; | |
1644 | int r = DM_MAPIO_REMAPPED; | |
1645 | chunk_t chunk; | |
1646 | ||
d87f4c14 | 1647 | if (bio->bi_rw & REQ_FLUSH) { |
57cba5d3 | 1648 | if (!map_context->target_request_nr) |
10b8106a MS |
1649 | bio->bi_bdev = s->origin->bdev; |
1650 | else | |
1651 | bio->bi_bdev = s->cow->bdev; | |
1652 | map_context->ptr = NULL; | |
1653 | return DM_MAPIO_REMAPPED; | |
1654 | } | |
1655 | ||
3452c2a1 MP |
1656 | chunk = sector_to_chunk(s->store, bio->bi_sector); |
1657 | ||
9fe86254 | 1658 | down_write(&s->lock); |
3452c2a1 | 1659 | |
d2fdb776 MP |
1660 | /* Full merging snapshots are redirected to the origin */ |
1661 | if (!s->valid) | |
1662 | goto redirect_to_origin; | |
3452c2a1 MP |
1663 | |
1664 | /* If the block is already remapped - use that */ | |
1665 | e = dm_lookup_exception(&s->complete, chunk); | |
1666 | if (e) { | |
9fe86254 MP |
1667 | /* Queue writes overlapping with chunks being merged */ |
1668 | if (bio_rw(bio) == WRITE && | |
1669 | chunk >= s->first_merging_chunk && | |
1670 | chunk < (s->first_merging_chunk + | |
1671 | s->num_merging_chunks)) { | |
1672 | bio->bi_bdev = s->origin->bdev; | |
1673 | bio_list_add(&s->bios_queued_during_merge, bio); | |
1674 | r = DM_MAPIO_SUBMITTED; | |
1675 | goto out_unlock; | |
1676 | } | |
17aa0332 | 1677 | |
3452c2a1 | 1678 | remap_exception(s, e, bio, chunk); |
17aa0332 MP |
1679 | |
1680 | if (bio_rw(bio) == WRITE) | |
1681 | map_context->ptr = track_chunk(s, chunk); | |
3452c2a1 MP |
1682 | goto out_unlock; |
1683 | } | |
1684 | ||
d2fdb776 | 1685 | redirect_to_origin: |
3452c2a1 MP |
1686 | bio->bi_bdev = s->origin->bdev; |
1687 | ||
1688 | if (bio_rw(bio) == WRITE) { | |
9fe86254 | 1689 | up_write(&s->lock); |
3452c2a1 MP |
1690 | return do_origin(s->origin, bio); |
1691 | } | |
1692 | ||
1693 | out_unlock: | |
9fe86254 | 1694 | up_write(&s->lock); |
3452c2a1 MP |
1695 | |
1696 | return r; | |
1697 | } | |
1698 | ||
cd45daff MP |
1699 | static int snapshot_end_io(struct dm_target *ti, struct bio *bio, |
1700 | int error, union map_info *map_context) | |
1701 | { | |
1702 | struct dm_snapshot *s = ti->private; | |
1703 | struct dm_snap_tracked_chunk *c = map_context->ptr; | |
1704 | ||
1705 | if (c) | |
1706 | stop_tracking_chunk(s, c); | |
1707 | ||
1708 | return 0; | |
1709 | } | |
1710 | ||
1e03f97e MP |
1711 | static void snapshot_merge_presuspend(struct dm_target *ti) |
1712 | { | |
1713 | struct dm_snapshot *s = ti->private; | |
1714 | ||
1715 | stop_merge(s); | |
1716 | } | |
1717 | ||
c1f0c183 MS |
1718 | static int snapshot_preresume(struct dm_target *ti) |
1719 | { | |
1720 | int r = 0; | |
1721 | struct dm_snapshot *s = ti->private; | |
1722 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; | |
1723 | ||
1724 | down_read(&_origins_lock); | |
9d3b15c4 | 1725 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1726 | if (snap_src && snap_dest) { |
1727 | down_read(&snap_src->lock); | |
1728 | if (s == snap_src) { | |
1729 | DMERR("Unable to resume snapshot source until " | |
1730 | "handover completes."); | |
1731 | r = -EINVAL; | |
b83b2f29 | 1732 | } else if (!dm_suspended(snap_src->ti)) { |
c1f0c183 MS |
1733 | DMERR("Unable to perform snapshot handover until " |
1734 | "source is suspended."); | |
1735 | r = -EINVAL; | |
1736 | } | |
1737 | up_read(&snap_src->lock); | |
1738 | } | |
1739 | up_read(&_origins_lock); | |
1740 | ||
1741 | return r; | |
1742 | } | |
1743 | ||
1da177e4 LT |
1744 | static void snapshot_resume(struct dm_target *ti) |
1745 | { | |
028867ac | 1746 | struct dm_snapshot *s = ti->private; |
c1f0c183 MS |
1747 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; |
1748 | ||
1749 | down_read(&_origins_lock); | |
9d3b15c4 | 1750 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1751 | if (snap_src && snap_dest) { |
1752 | down_write(&snap_src->lock); | |
1753 | down_write_nested(&snap_dest->lock, SINGLE_DEPTH_NESTING); | |
1754 | __handover_exceptions(snap_src, snap_dest); | |
1755 | up_write(&snap_dest->lock); | |
1756 | up_write(&snap_src->lock); | |
1757 | } | |
1758 | up_read(&_origins_lock); | |
1759 | ||
1760 | /* Now we have correct chunk size, reregister */ | |
1761 | reregister_snapshot(s); | |
1da177e4 | 1762 | |
aa14edeb AK |
1763 | down_write(&s->lock); |
1764 | s->active = 1; | |
1765 | up_write(&s->lock); | |
1da177e4 LT |
1766 | } |
1767 | ||
1e03f97e MP |
1768 | static sector_t get_origin_minimum_chunksize(struct block_device *bdev) |
1769 | { | |
1770 | sector_t min_chunksize; | |
1771 | ||
1772 | down_read(&_origins_lock); | |
1773 | min_chunksize = __minimum_chunk_size(__lookup_origin(bdev)); | |
1774 | up_read(&_origins_lock); | |
1775 | ||
1776 | return min_chunksize; | |
1777 | } | |
1778 | ||
1779 | static void snapshot_merge_resume(struct dm_target *ti) | |
1780 | { | |
1781 | struct dm_snapshot *s = ti->private; | |
1782 | ||
1783 | /* | |
1784 | * Handover exceptions from existing snapshot. | |
1785 | */ | |
1786 | snapshot_resume(ti); | |
1787 | ||
1788 | /* | |
1789 | * snapshot-merge acts as an origin, so set ti->split_io | |
1790 | */ | |
1791 | ti->split_io = get_origin_minimum_chunksize(s->origin->bdev); | |
1792 | ||
1793 | start_merge(s); | |
1794 | } | |
1795 | ||
1da177e4 LT |
1796 | static int snapshot_status(struct dm_target *ti, status_type_t type, |
1797 | char *result, unsigned int maxlen) | |
1798 | { | |
2e4a31df | 1799 | unsigned sz = 0; |
028867ac | 1800 | struct dm_snapshot *snap = ti->private; |
1da177e4 LT |
1801 | |
1802 | switch (type) { | |
1803 | case STATUSTYPE_INFO: | |
94e76572 MP |
1804 | |
1805 | down_write(&snap->lock); | |
1806 | ||
1da177e4 | 1807 | if (!snap->valid) |
2e4a31df | 1808 | DMEMIT("Invalid"); |
d8ddb1cf MS |
1809 | else if (snap->merge_failed) |
1810 | DMEMIT("Merge failed"); | |
1da177e4 | 1811 | else { |
985903bb MS |
1812 | if (snap->store->type->usage) { |
1813 | sector_t total_sectors, sectors_allocated, | |
1814 | metadata_sectors; | |
1815 | snap->store->type->usage(snap->store, | |
1816 | &total_sectors, | |
1817 | §ors_allocated, | |
1818 | &metadata_sectors); | |
1819 | DMEMIT("%llu/%llu %llu", | |
1820 | (unsigned long long)sectors_allocated, | |
1821 | (unsigned long long)total_sectors, | |
1822 | (unsigned long long)metadata_sectors); | |
1da177e4 LT |
1823 | } |
1824 | else | |
2e4a31df | 1825 | DMEMIT("Unknown"); |
1da177e4 | 1826 | } |
94e76572 MP |
1827 | |
1828 | up_write(&snap->lock); | |
1829 | ||
1da177e4 LT |
1830 | break; |
1831 | ||
1832 | case STATUSTYPE_TABLE: | |
1833 | /* | |
1834 | * kdevname returns a static pointer so we need | |
1835 | * to make private copies if the output is to | |
1836 | * make sense. | |
1837 | */ | |
fc56f6fb | 1838 | DMEMIT("%s %s", snap->origin->name, snap->cow->name); |
1e302a92 JB |
1839 | snap->store->type->status(snap->store, type, result + sz, |
1840 | maxlen - sz); | |
1da177e4 LT |
1841 | break; |
1842 | } | |
1843 | ||
1844 | return 0; | |
1845 | } | |
1846 | ||
8811f46c MS |
1847 | static int snapshot_iterate_devices(struct dm_target *ti, |
1848 | iterate_devices_callout_fn fn, void *data) | |
1849 | { | |
1850 | struct dm_snapshot *snap = ti->private; | |
1e5554c8 MP |
1851 | int r; |
1852 | ||
1853 | r = fn(ti, snap->origin, 0, ti->len, data); | |
8811f46c | 1854 | |
1e5554c8 MP |
1855 | if (!r) |
1856 | r = fn(ti, snap->cow, 0, get_dev_size(snap->cow->bdev), data); | |
1857 | ||
1858 | return r; | |
8811f46c MS |
1859 | } |
1860 | ||
1861 | ||
1da177e4 LT |
1862 | /*----------------------------------------------------------------- |
1863 | * Origin methods | |
1864 | *---------------------------------------------------------------*/ | |
9eaae8ff MP |
1865 | |
1866 | /* | |
1867 | * If no exceptions need creating, DM_MAPIO_REMAPPED is returned and any | |
1868 | * supplied bio was ignored. The caller may submit it immediately. | |
1869 | * (No remapping actually occurs as the origin is always a direct linear | |
1870 | * map.) | |
1871 | * | |
1872 | * If further exceptions are required, DM_MAPIO_SUBMITTED is returned | |
1873 | * and any supplied bio is added to a list to be submitted once all | |
1874 | * the necessary exceptions exist. | |
1875 | */ | |
1876 | static int __origin_write(struct list_head *snapshots, sector_t sector, | |
1877 | struct bio *bio) | |
1da177e4 | 1878 | { |
515ad66c | 1879 | int r = DM_MAPIO_REMAPPED; |
1da177e4 | 1880 | struct dm_snapshot *snap; |
1d4989c8 | 1881 | struct dm_exception *e; |
515ad66c MP |
1882 | struct dm_snap_pending_exception *pe; |
1883 | struct dm_snap_pending_exception *pe_to_start_now = NULL; | |
1884 | struct dm_snap_pending_exception *pe_to_start_last = NULL; | |
1da177e4 LT |
1885 | chunk_t chunk; |
1886 | ||
1887 | /* Do all the snapshots on this origin */ | |
1888 | list_for_each_entry (snap, snapshots, list) { | |
3452c2a1 MP |
1889 | /* |
1890 | * Don't make new exceptions in a merging snapshot | |
1891 | * because it has effectively been deleted | |
1892 | */ | |
1893 | if (dm_target_is_snapshot_merge(snap->ti)) | |
1894 | continue; | |
1895 | ||
76df1c65 AK |
1896 | down_write(&snap->lock); |
1897 | ||
aa14edeb AK |
1898 | /* Only deal with valid and active snapshots */ |
1899 | if (!snap->valid || !snap->active) | |
76df1c65 | 1900 | goto next_snapshot; |
1da177e4 | 1901 | |
d5e404c1 | 1902 | /* Nothing to do if writing beyond end of snapshot */ |
9eaae8ff | 1903 | if (sector >= dm_table_get_size(snap->ti->table)) |
76df1c65 | 1904 | goto next_snapshot; |
1da177e4 LT |
1905 | |
1906 | /* | |
1907 | * Remember, different snapshots can have | |
1908 | * different chunk sizes. | |
1909 | */ | |
9eaae8ff | 1910 | chunk = sector_to_chunk(snap->store, sector); |
1da177e4 LT |
1911 | |
1912 | /* | |
1913 | * Check exception table to see if block | |
1914 | * is already remapped in this snapshot | |
1915 | * and trigger an exception if not. | |
1916 | */ | |
3510cb94 | 1917 | e = dm_lookup_exception(&snap->complete, chunk); |
76df1c65 AK |
1918 | if (e) |
1919 | goto next_snapshot; | |
1920 | ||
2913808e | 1921 | pe = __lookup_pending_exception(snap, chunk); |
76df1c65 | 1922 | if (!pe) { |
c6621392 MP |
1923 | up_write(&snap->lock); |
1924 | pe = alloc_pending_exception(snap); | |
1925 | down_write(&snap->lock); | |
1926 | ||
1927 | if (!snap->valid) { | |
1928 | free_pending_exception(pe); | |
1929 | goto next_snapshot; | |
1930 | } | |
1931 | ||
3510cb94 | 1932 | e = dm_lookup_exception(&snap->complete, chunk); |
35bf659b MP |
1933 | if (e) { |
1934 | free_pending_exception(pe); | |
1935 | goto next_snapshot; | |
1936 | } | |
1937 | ||
c6621392 | 1938 | pe = __find_pending_exception(snap, pe, chunk); |
2913808e MP |
1939 | if (!pe) { |
1940 | __invalidate_snapshot(snap, -ENOMEM); | |
1941 | goto next_snapshot; | |
1942 | } | |
76df1c65 AK |
1943 | } |
1944 | ||
515ad66c | 1945 | r = DM_MAPIO_SUBMITTED; |
76df1c65 | 1946 | |
515ad66c MP |
1947 | /* |
1948 | * If an origin bio was supplied, queue it to wait for the | |
1949 | * completion of this exception, and start this one last, | |
1950 | * at the end of the function. | |
1951 | */ | |
1952 | if (bio) { | |
1953 | bio_list_add(&pe->origin_bios, bio); | |
1954 | bio = NULL; | |
76df1c65 | 1955 | |
515ad66c MP |
1956 | if (!pe->started) { |
1957 | pe->started = 1; | |
1958 | pe_to_start_last = pe; | |
1959 | } | |
76df1c65 AK |
1960 | } |
1961 | ||
1962 | if (!pe->started) { | |
1963 | pe->started = 1; | |
515ad66c | 1964 | pe_to_start_now = pe; |
1da177e4 LT |
1965 | } |
1966 | ||
76df1c65 | 1967 | next_snapshot: |
1da177e4 | 1968 | up_write(&snap->lock); |
1da177e4 | 1969 | |
515ad66c MP |
1970 | if (pe_to_start_now) { |
1971 | start_copy(pe_to_start_now); | |
1972 | pe_to_start_now = NULL; | |
1973 | } | |
b4b610f6 AK |
1974 | } |
1975 | ||
1da177e4 | 1976 | /* |
515ad66c MP |
1977 | * Submit the exception against which the bio is queued last, |
1978 | * to give the other exceptions a head start. | |
1da177e4 | 1979 | */ |
515ad66c MP |
1980 | if (pe_to_start_last) |
1981 | start_copy(pe_to_start_last); | |
1da177e4 LT |
1982 | |
1983 | return r; | |
1984 | } | |
1985 | ||
1986 | /* | |
1987 | * Called on a write from the origin driver. | |
1988 | */ | |
1989 | static int do_origin(struct dm_dev *origin, struct bio *bio) | |
1990 | { | |
1991 | struct origin *o; | |
d2a7ad29 | 1992 | int r = DM_MAPIO_REMAPPED; |
1da177e4 LT |
1993 | |
1994 | down_read(&_origins_lock); | |
1995 | o = __lookup_origin(origin->bdev); | |
1996 | if (o) | |
9eaae8ff | 1997 | r = __origin_write(&o->snapshots, bio->bi_sector, bio); |
1da177e4 LT |
1998 | up_read(&_origins_lock); |
1999 | ||
2000 | return r; | |
2001 | } | |
2002 | ||
73dfd078 MP |
2003 | /* |
2004 | * Trigger exceptions in all non-merging snapshots. | |
2005 | * | |
2006 | * The chunk size of the merging snapshot may be larger than the chunk | |
2007 | * size of some other snapshot so we may need to reallocate multiple | |
2008 | * chunks in other snapshots. | |
2009 | * | |
2010 | * We scan all the overlapping exceptions in the other snapshots. | |
2011 | * Returns 1 if anything was reallocated and must be waited for, | |
2012 | * otherwise returns 0. | |
2013 | * | |
2014 | * size must be a multiple of merging_snap's chunk_size. | |
2015 | */ | |
2016 | static int origin_write_extent(struct dm_snapshot *merging_snap, | |
2017 | sector_t sector, unsigned size) | |
2018 | { | |
2019 | int must_wait = 0; | |
2020 | sector_t n; | |
2021 | struct origin *o; | |
2022 | ||
2023 | /* | |
2024 | * The origin's __minimum_chunk_size() got stored in split_io | |
2025 | * by snapshot_merge_resume(). | |
2026 | */ | |
2027 | down_read(&_origins_lock); | |
2028 | o = __lookup_origin(merging_snap->origin->bdev); | |
2029 | for (n = 0; n < size; n += merging_snap->ti->split_io) | |
2030 | if (__origin_write(&o->snapshots, sector + n, NULL) == | |
2031 | DM_MAPIO_SUBMITTED) | |
2032 | must_wait = 1; | |
2033 | up_read(&_origins_lock); | |
2034 | ||
2035 | return must_wait; | |
2036 | } | |
2037 | ||
1da177e4 LT |
2038 | /* |
2039 | * Origin: maps a linear range of a device, with hooks for snapshotting. | |
2040 | */ | |
2041 | ||
2042 | /* | |
2043 | * Construct an origin mapping: <dev_path> | |
2044 | * The context for an origin is merely a 'struct dm_dev *' | |
2045 | * pointing to the real device. | |
2046 | */ | |
2047 | static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
2048 | { | |
2049 | int r; | |
2050 | struct dm_dev *dev; | |
2051 | ||
2052 | if (argc != 1) { | |
72d94861 | 2053 | ti->error = "origin: incorrect number of arguments"; |
1da177e4 LT |
2054 | return -EINVAL; |
2055 | } | |
2056 | ||
8215d6ec | 2057 | r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev); |
1da177e4 LT |
2058 | if (r) { |
2059 | ti->error = "Cannot get target device"; | |
2060 | return r; | |
2061 | } | |
2062 | ||
2063 | ti->private = dev; | |
494b3ee7 MP |
2064 | ti->num_flush_requests = 1; |
2065 | ||
1da177e4 LT |
2066 | return 0; |
2067 | } | |
2068 | ||
2069 | static void origin_dtr(struct dm_target *ti) | |
2070 | { | |
028867ac | 2071 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2072 | dm_put_device(ti, dev); |
2073 | } | |
2074 | ||
2075 | static int origin_map(struct dm_target *ti, struct bio *bio, | |
2076 | union map_info *map_context) | |
2077 | { | |
028867ac | 2078 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2079 | bio->bi_bdev = dev->bdev; |
2080 | ||
d87f4c14 | 2081 | if (bio->bi_rw & REQ_FLUSH) |
494b3ee7 MP |
2082 | return DM_MAPIO_REMAPPED; |
2083 | ||
1da177e4 | 2084 | /* Only tell snapshots if this is a write */ |
d2a7ad29 | 2085 | return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; |
1da177e4 LT |
2086 | } |
2087 | ||
1da177e4 LT |
2088 | /* |
2089 | * Set the target "split_io" field to the minimum of all the snapshots' | |
2090 | * chunk sizes. | |
2091 | */ | |
2092 | static void origin_resume(struct dm_target *ti) | |
2093 | { | |
028867ac | 2094 | struct dm_dev *dev = ti->private; |
1da177e4 | 2095 | |
1e03f97e | 2096 | ti->split_io = get_origin_minimum_chunksize(dev->bdev); |
1da177e4 LT |
2097 | } |
2098 | ||
2099 | static int origin_status(struct dm_target *ti, status_type_t type, char *result, | |
2100 | unsigned int maxlen) | |
2101 | { | |
028867ac | 2102 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2103 | |
2104 | switch (type) { | |
2105 | case STATUSTYPE_INFO: | |
2106 | result[0] = '\0'; | |
2107 | break; | |
2108 | ||
2109 | case STATUSTYPE_TABLE: | |
2110 | snprintf(result, maxlen, "%s", dev->name); | |
2111 | break; | |
2112 | } | |
2113 | ||
2114 | return 0; | |
2115 | } | |
2116 | ||
b1d55528 MP |
2117 | static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
2118 | struct bio_vec *biovec, int max_size) | |
2119 | { | |
2120 | struct dm_dev *dev = ti->private; | |
2121 | struct request_queue *q = bdev_get_queue(dev->bdev); | |
2122 | ||
2123 | if (!q->merge_bvec_fn) | |
2124 | return max_size; | |
2125 | ||
2126 | bvm->bi_bdev = dev->bdev; | |
2127 | bvm->bi_sector = bvm->bi_sector; | |
2128 | ||
2129 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
2130 | } | |
2131 | ||
8811f46c MS |
2132 | static int origin_iterate_devices(struct dm_target *ti, |
2133 | iterate_devices_callout_fn fn, void *data) | |
2134 | { | |
2135 | struct dm_dev *dev = ti->private; | |
2136 | ||
2137 | return fn(ti, dev, 0, ti->len, data); | |
2138 | } | |
2139 | ||
1da177e4 LT |
2140 | static struct target_type origin_target = { |
2141 | .name = "snapshot-origin", | |
b83b2f29 | 2142 | .version = {1, 7, 1}, |
1da177e4 LT |
2143 | .module = THIS_MODULE, |
2144 | .ctr = origin_ctr, | |
2145 | .dtr = origin_dtr, | |
2146 | .map = origin_map, | |
2147 | .resume = origin_resume, | |
2148 | .status = origin_status, | |
b1d55528 | 2149 | .merge = origin_merge, |
8811f46c | 2150 | .iterate_devices = origin_iterate_devices, |
1da177e4 LT |
2151 | }; |
2152 | ||
2153 | static struct target_type snapshot_target = { | |
2154 | .name = "snapshot", | |
b83b2f29 | 2155 | .version = {1, 10, 0}, |
1da177e4 LT |
2156 | .module = THIS_MODULE, |
2157 | .ctr = snapshot_ctr, | |
2158 | .dtr = snapshot_dtr, | |
2159 | .map = snapshot_map, | |
cd45daff | 2160 | .end_io = snapshot_end_io, |
c1f0c183 | 2161 | .preresume = snapshot_preresume, |
1da177e4 LT |
2162 | .resume = snapshot_resume, |
2163 | .status = snapshot_status, | |
8811f46c | 2164 | .iterate_devices = snapshot_iterate_devices, |
1da177e4 LT |
2165 | }; |
2166 | ||
d698aa45 MP |
2167 | static struct target_type merge_target = { |
2168 | .name = dm_snapshot_merge_target_name, | |
b83b2f29 | 2169 | .version = {1, 1, 0}, |
d698aa45 MP |
2170 | .module = THIS_MODULE, |
2171 | .ctr = snapshot_ctr, | |
2172 | .dtr = snapshot_dtr, | |
3452c2a1 | 2173 | .map = snapshot_merge_map, |
d698aa45 | 2174 | .end_io = snapshot_end_io, |
1e03f97e | 2175 | .presuspend = snapshot_merge_presuspend, |
d698aa45 | 2176 | .preresume = snapshot_preresume, |
1e03f97e | 2177 | .resume = snapshot_merge_resume, |
d698aa45 MP |
2178 | .status = snapshot_status, |
2179 | .iterate_devices = snapshot_iterate_devices, | |
2180 | }; | |
2181 | ||
1da177e4 LT |
2182 | static int __init dm_snapshot_init(void) |
2183 | { | |
2184 | int r; | |
2185 | ||
4db6bfe0 AK |
2186 | r = dm_exception_store_init(); |
2187 | if (r) { | |
2188 | DMERR("Failed to initialize exception stores"); | |
2189 | return r; | |
2190 | } | |
2191 | ||
1da177e4 | 2192 | r = dm_register_target(&snapshot_target); |
d698aa45 | 2193 | if (r < 0) { |
1da177e4 | 2194 | DMERR("snapshot target register failed %d", r); |
034a186d | 2195 | goto bad_register_snapshot_target; |
1da177e4 LT |
2196 | } |
2197 | ||
2198 | r = dm_register_target(&origin_target); | |
2199 | if (r < 0) { | |
72d94861 | 2200 | DMERR("Origin target register failed %d", r); |
d698aa45 MP |
2201 | goto bad_register_origin_target; |
2202 | } | |
2203 | ||
2204 | r = dm_register_target(&merge_target); | |
2205 | if (r < 0) { | |
2206 | DMERR("Merge target register failed %d", r); | |
2207 | goto bad_register_merge_target; | |
1da177e4 LT |
2208 | } |
2209 | ||
2210 | r = init_origin_hash(); | |
2211 | if (r) { | |
2212 | DMERR("init_origin_hash failed."); | |
d698aa45 | 2213 | goto bad_origin_hash; |
1da177e4 LT |
2214 | } |
2215 | ||
1d4989c8 | 2216 | exception_cache = KMEM_CACHE(dm_exception, 0); |
1da177e4 LT |
2217 | if (!exception_cache) { |
2218 | DMERR("Couldn't create exception cache."); | |
2219 | r = -ENOMEM; | |
d698aa45 | 2220 | goto bad_exception_cache; |
1da177e4 LT |
2221 | } |
2222 | ||
028867ac | 2223 | pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0); |
1da177e4 LT |
2224 | if (!pending_cache) { |
2225 | DMERR("Couldn't create pending cache."); | |
2226 | r = -ENOMEM; | |
d698aa45 | 2227 | goto bad_pending_cache; |
1da177e4 LT |
2228 | } |
2229 | ||
cd45daff MP |
2230 | tracked_chunk_cache = KMEM_CACHE(dm_snap_tracked_chunk, 0); |
2231 | if (!tracked_chunk_cache) { | |
2232 | DMERR("Couldn't create cache to track chunks in use."); | |
2233 | r = -ENOMEM; | |
d698aa45 | 2234 | goto bad_tracked_chunk_cache; |
cd45daff MP |
2235 | } |
2236 | ||
1da177e4 LT |
2237 | return 0; |
2238 | ||
d698aa45 | 2239 | bad_tracked_chunk_cache: |
1da177e4 | 2240 | kmem_cache_destroy(pending_cache); |
d698aa45 | 2241 | bad_pending_cache: |
1da177e4 | 2242 | kmem_cache_destroy(exception_cache); |
d698aa45 | 2243 | bad_exception_cache: |
1da177e4 | 2244 | exit_origin_hash(); |
d698aa45 MP |
2245 | bad_origin_hash: |
2246 | dm_unregister_target(&merge_target); | |
2247 | bad_register_merge_target: | |
1da177e4 | 2248 | dm_unregister_target(&origin_target); |
d698aa45 | 2249 | bad_register_origin_target: |
1da177e4 | 2250 | dm_unregister_target(&snapshot_target); |
034a186d JB |
2251 | bad_register_snapshot_target: |
2252 | dm_exception_store_exit(); | |
d698aa45 | 2253 | |
1da177e4 LT |
2254 | return r; |
2255 | } | |
2256 | ||
2257 | static void __exit dm_snapshot_exit(void) | |
2258 | { | |
10d3bd09 MP |
2259 | dm_unregister_target(&snapshot_target); |
2260 | dm_unregister_target(&origin_target); | |
d698aa45 | 2261 | dm_unregister_target(&merge_target); |
1da177e4 LT |
2262 | |
2263 | exit_origin_hash(); | |
1da177e4 LT |
2264 | kmem_cache_destroy(pending_cache); |
2265 | kmem_cache_destroy(exception_cache); | |
cd45daff | 2266 | kmem_cache_destroy(tracked_chunk_cache); |
4db6bfe0 AK |
2267 | |
2268 | dm_exception_store_exit(); | |
1da177e4 LT |
2269 | } |
2270 | ||
2271 | /* Module hooks */ | |
2272 | module_init(dm_snapshot_init); | |
2273 | module_exit(dm_snapshot_exit); | |
2274 | ||
2275 | MODULE_DESCRIPTION(DM_NAME " snapshot target"); | |
2276 | MODULE_AUTHOR("Joe Thornber"); | |
2277 | MODULE_LICENSE("GPL"); |