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 | ||
1da177e4 LT |
32 | /* |
33 | * The percentage increment we will wake up users at | |
34 | */ | |
35 | #define WAKE_UP_PERCENT 5 | |
36 | ||
37 | /* | |
38 | * kcopyd priority of snapshot operations | |
39 | */ | |
40 | #define SNAPSHOT_COPY_PRIORITY 2 | |
41 | ||
cd45daff MP |
42 | /* |
43 | * The size of the mempool used to track chunks in use. | |
44 | */ | |
45 | #define MIN_IOS 256 | |
46 | ||
ccc45ea8 JB |
47 | #define DM_TRACKED_CHUNK_HASH_SIZE 16 |
48 | #define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \ | |
49 | (DM_TRACKED_CHUNK_HASH_SIZE - 1)) | |
50 | ||
191437a5 | 51 | struct dm_exception_table { |
ccc45ea8 JB |
52 | uint32_t hash_mask; |
53 | unsigned hash_shift; | |
54 | struct list_head *table; | |
55 | }; | |
56 | ||
57 | struct dm_snapshot { | |
58 | struct rw_semaphore lock; | |
59 | ||
60 | struct dm_dev *origin; | |
fc56f6fb MS |
61 | struct dm_dev *cow; |
62 | ||
63 | struct dm_target *ti; | |
ccc45ea8 JB |
64 | |
65 | /* List of snapshots per Origin */ | |
66 | struct list_head list; | |
67 | ||
d8ddb1cf MS |
68 | /* |
69 | * You can't use a snapshot if this is 0 (e.g. if full). | |
70 | * A snapshot-merge target never clears this. | |
71 | */ | |
ccc45ea8 JB |
72 | int valid; |
73 | ||
74 | /* Origin writes don't trigger exceptions until this is set */ | |
75 | int active; | |
76 | ||
ccc45ea8 JB |
77 | atomic_t pending_exceptions_count; |
78 | ||
924e600d MS |
79 | mempool_t *pending_pool; |
80 | ||
191437a5 JB |
81 | struct dm_exception_table pending; |
82 | struct dm_exception_table complete; | |
ccc45ea8 JB |
83 | |
84 | /* | |
85 | * pe_lock protects all pending_exception operations and access | |
86 | * as well as the snapshot_bios list. | |
87 | */ | |
88 | spinlock_t pe_lock; | |
89 | ||
924e600d MS |
90 | /* Chunks with outstanding reads */ |
91 | spinlock_t tracked_chunk_lock; | |
92 | mempool_t *tracked_chunk_pool; | |
93 | struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE]; | |
94 | ||
ccc45ea8 JB |
95 | /* The on disk metadata handler */ |
96 | struct dm_exception_store *store; | |
97 | ||
98 | struct dm_kcopyd_client *kcopyd_client; | |
99 | ||
924e600d MS |
100 | /* Wait for events based on state_bits */ |
101 | unsigned long state_bits; | |
102 | ||
103 | /* Range of chunks currently being merged. */ | |
104 | chunk_t first_merging_chunk; | |
105 | int num_merging_chunks; | |
1e03f97e | 106 | |
d8ddb1cf MS |
107 | /* |
108 | * The merge operation failed if this flag is set. | |
109 | * Failure modes are handled as follows: | |
110 | * - I/O error reading the header | |
111 | * => don't load the target; abort. | |
112 | * - Header does not have "valid" flag set | |
113 | * => use the origin; forget about the snapshot. | |
114 | * - I/O error when reading exceptions | |
115 | * => don't load the target; abort. | |
116 | * (We can't use the intermediate origin state.) | |
117 | * - I/O error while merging | |
118 | * => stop merging; set merge_failed; process I/O normally. | |
119 | */ | |
120 | int merge_failed; | |
121 | ||
9fe86254 MP |
122 | /* |
123 | * Incoming bios that overlap with chunks being merged must wait | |
124 | * for them to be committed. | |
125 | */ | |
126 | struct bio_list bios_queued_during_merge; | |
ccc45ea8 JB |
127 | }; |
128 | ||
1e03f97e MP |
129 | /* |
130 | * state_bits: | |
131 | * RUNNING_MERGE - Merge operation is in progress. | |
132 | * SHUTDOWN_MERGE - Set to signal that merge needs to be stopped; | |
133 | * cleared afterwards. | |
134 | */ | |
135 | #define RUNNING_MERGE 0 | |
136 | #define SHUTDOWN_MERGE 1 | |
137 | ||
c2411045 MP |
138 | struct dm_dev *dm_snap_origin(struct dm_snapshot *s) |
139 | { | |
140 | return s->origin; | |
141 | } | |
142 | EXPORT_SYMBOL(dm_snap_origin); | |
143 | ||
fc56f6fb MS |
144 | struct dm_dev *dm_snap_cow(struct dm_snapshot *s) |
145 | { | |
146 | return s->cow; | |
147 | } | |
148 | EXPORT_SYMBOL(dm_snap_cow); | |
149 | ||
ccc45ea8 JB |
150 | static sector_t chunk_to_sector(struct dm_exception_store *store, |
151 | chunk_t chunk) | |
152 | { | |
153 | return chunk << store->chunk_shift; | |
154 | } | |
155 | ||
156 | static int bdev_equal(struct block_device *lhs, struct block_device *rhs) | |
157 | { | |
158 | /* | |
159 | * There is only ever one instance of a particular block | |
160 | * device so we can compare pointers safely. | |
161 | */ | |
162 | return lhs == rhs; | |
163 | } | |
164 | ||
028867ac | 165 | struct dm_snap_pending_exception { |
1d4989c8 | 166 | struct dm_exception e; |
1da177e4 LT |
167 | |
168 | /* | |
169 | * Origin buffers waiting for this to complete are held | |
170 | * in a bio list | |
171 | */ | |
172 | struct bio_list origin_bios; | |
173 | struct bio_list snapshot_bios; | |
174 | ||
1da177e4 LT |
175 | /* Pointer back to snapshot context */ |
176 | struct dm_snapshot *snap; | |
177 | ||
178 | /* | |
179 | * 1 indicates the exception has already been sent to | |
180 | * kcopyd. | |
181 | */ | |
182 | int started; | |
183 | }; | |
184 | ||
185 | /* | |
186 | * Hash table mapping origin volumes to lists of snapshots and | |
187 | * a lock to protect it | |
188 | */ | |
e18b890b CL |
189 | static struct kmem_cache *exception_cache; |
190 | static struct kmem_cache *pending_cache; | |
1da177e4 | 191 | |
cd45daff MP |
192 | struct dm_snap_tracked_chunk { |
193 | struct hlist_node node; | |
194 | chunk_t chunk; | |
195 | }; | |
196 | ||
197 | static struct kmem_cache *tracked_chunk_cache; | |
198 | ||
199 | static struct dm_snap_tracked_chunk *track_chunk(struct dm_snapshot *s, | |
200 | chunk_t chunk) | |
201 | { | |
202 | struct dm_snap_tracked_chunk *c = mempool_alloc(s->tracked_chunk_pool, | |
203 | GFP_NOIO); | |
204 | unsigned long flags; | |
205 | ||
206 | c->chunk = chunk; | |
207 | ||
208 | spin_lock_irqsave(&s->tracked_chunk_lock, flags); | |
209 | hlist_add_head(&c->node, | |
210 | &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)]); | |
211 | spin_unlock_irqrestore(&s->tracked_chunk_lock, flags); | |
212 | ||
213 | return c; | |
214 | } | |
215 | ||
216 | static void stop_tracking_chunk(struct dm_snapshot *s, | |
217 | struct dm_snap_tracked_chunk *c) | |
218 | { | |
219 | unsigned long flags; | |
220 | ||
221 | spin_lock_irqsave(&s->tracked_chunk_lock, flags); | |
222 | hlist_del(&c->node); | |
223 | spin_unlock_irqrestore(&s->tracked_chunk_lock, flags); | |
224 | ||
225 | mempool_free(c, s->tracked_chunk_pool); | |
226 | } | |
227 | ||
a8d41b59 MP |
228 | static int __chunk_is_tracked(struct dm_snapshot *s, chunk_t chunk) |
229 | { | |
230 | struct dm_snap_tracked_chunk *c; | |
231 | struct hlist_node *hn; | |
232 | int found = 0; | |
233 | ||
234 | spin_lock_irq(&s->tracked_chunk_lock); | |
235 | ||
236 | hlist_for_each_entry(c, hn, | |
237 | &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)], node) { | |
238 | if (c->chunk == chunk) { | |
239 | found = 1; | |
240 | break; | |
241 | } | |
242 | } | |
243 | ||
244 | spin_unlock_irq(&s->tracked_chunk_lock); | |
245 | ||
246 | return found; | |
247 | } | |
248 | ||
615d1eb9 MS |
249 | /* |
250 | * This conflicting I/O is extremely improbable in the caller, | |
251 | * so msleep(1) is sufficient and there is no need for a wait queue. | |
252 | */ | |
253 | static void __check_for_conflicting_io(struct dm_snapshot *s, chunk_t chunk) | |
254 | { | |
255 | while (__chunk_is_tracked(s, chunk)) | |
256 | msleep(1); | |
257 | } | |
258 | ||
1da177e4 LT |
259 | /* |
260 | * One of these per registered origin, held in the snapshot_origins hash | |
261 | */ | |
262 | struct origin { | |
263 | /* The origin device */ | |
264 | struct block_device *bdev; | |
265 | ||
266 | struct list_head hash_list; | |
267 | ||
268 | /* List of snapshots for this origin */ | |
269 | struct list_head snapshots; | |
270 | }; | |
271 | ||
272 | /* | |
273 | * Size of the hash table for origin volumes. If we make this | |
274 | * the size of the minors list then it should be nearly perfect | |
275 | */ | |
276 | #define ORIGIN_HASH_SIZE 256 | |
277 | #define ORIGIN_MASK 0xFF | |
278 | static struct list_head *_origins; | |
279 | static struct rw_semaphore _origins_lock; | |
280 | ||
73dfd078 MP |
281 | static DECLARE_WAIT_QUEUE_HEAD(_pending_exceptions_done); |
282 | static DEFINE_SPINLOCK(_pending_exceptions_done_spinlock); | |
283 | static uint64_t _pending_exceptions_done_count; | |
284 | ||
1da177e4 LT |
285 | static int init_origin_hash(void) |
286 | { | |
287 | int i; | |
288 | ||
289 | _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), | |
290 | GFP_KERNEL); | |
291 | if (!_origins) { | |
72d94861 | 292 | DMERR("unable to allocate memory"); |
1da177e4 LT |
293 | return -ENOMEM; |
294 | } | |
295 | ||
296 | for (i = 0; i < ORIGIN_HASH_SIZE; i++) | |
297 | INIT_LIST_HEAD(_origins + i); | |
298 | init_rwsem(&_origins_lock); | |
299 | ||
300 | return 0; | |
301 | } | |
302 | ||
303 | static void exit_origin_hash(void) | |
304 | { | |
305 | kfree(_origins); | |
306 | } | |
307 | ||
028867ac | 308 | static unsigned origin_hash(struct block_device *bdev) |
1da177e4 LT |
309 | { |
310 | return bdev->bd_dev & ORIGIN_MASK; | |
311 | } | |
312 | ||
313 | static struct origin *__lookup_origin(struct block_device *origin) | |
314 | { | |
315 | struct list_head *ol; | |
316 | struct origin *o; | |
317 | ||
318 | ol = &_origins[origin_hash(origin)]; | |
319 | list_for_each_entry (o, ol, hash_list) | |
320 | if (bdev_equal(o->bdev, origin)) | |
321 | return o; | |
322 | ||
323 | return NULL; | |
324 | } | |
325 | ||
326 | static void __insert_origin(struct origin *o) | |
327 | { | |
328 | struct list_head *sl = &_origins[origin_hash(o->bdev)]; | |
329 | list_add_tail(&o->hash_list, sl); | |
330 | } | |
331 | ||
c1f0c183 MS |
332 | /* |
333 | * _origins_lock must be held when calling this function. | |
334 | * Returns number of snapshots registered using the supplied cow device, plus: | |
335 | * snap_src - a snapshot suitable for use as a source of exception handover | |
336 | * snap_dest - a snapshot capable of receiving exception handover. | |
9d3b15c4 MP |
337 | * snap_merge - an existing snapshot-merge target linked to the same origin. |
338 | * There can be at most one snapshot-merge target. The parameter is optional. | |
c1f0c183 | 339 | * |
9d3b15c4 | 340 | * Possible return values and states of snap_src and snap_dest. |
c1f0c183 MS |
341 | * 0: NULL, NULL - first new snapshot |
342 | * 1: snap_src, NULL - normal snapshot | |
343 | * 2: snap_src, snap_dest - waiting for handover | |
344 | * 2: snap_src, NULL - handed over, waiting for old to be deleted | |
345 | * 1: NULL, snap_dest - source got destroyed without handover | |
346 | */ | |
347 | static int __find_snapshots_sharing_cow(struct dm_snapshot *snap, | |
348 | struct dm_snapshot **snap_src, | |
9d3b15c4 MP |
349 | struct dm_snapshot **snap_dest, |
350 | struct dm_snapshot **snap_merge) | |
c1f0c183 MS |
351 | { |
352 | struct dm_snapshot *s; | |
353 | struct origin *o; | |
354 | int count = 0; | |
355 | int active; | |
356 | ||
357 | o = __lookup_origin(snap->origin->bdev); | |
358 | if (!o) | |
359 | goto out; | |
360 | ||
361 | list_for_each_entry(s, &o->snapshots, list) { | |
9d3b15c4 MP |
362 | if (dm_target_is_snapshot_merge(s->ti) && snap_merge) |
363 | *snap_merge = s; | |
c1f0c183 MS |
364 | if (!bdev_equal(s->cow->bdev, snap->cow->bdev)) |
365 | continue; | |
366 | ||
367 | down_read(&s->lock); | |
368 | active = s->active; | |
369 | up_read(&s->lock); | |
370 | ||
371 | if (active) { | |
372 | if (snap_src) | |
373 | *snap_src = s; | |
374 | } else if (snap_dest) | |
375 | *snap_dest = s; | |
376 | ||
377 | count++; | |
378 | } | |
379 | ||
380 | out: | |
381 | return count; | |
382 | } | |
383 | ||
384 | /* | |
385 | * On success, returns 1 if this snapshot is a handover destination, | |
386 | * otherwise returns 0. | |
387 | */ | |
388 | static int __validate_exception_handover(struct dm_snapshot *snap) | |
389 | { | |
390 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; | |
9d3b15c4 | 391 | struct dm_snapshot *snap_merge = NULL; |
c1f0c183 MS |
392 | |
393 | /* Does snapshot need exceptions handed over to it? */ | |
9d3b15c4 MP |
394 | if ((__find_snapshots_sharing_cow(snap, &snap_src, &snap_dest, |
395 | &snap_merge) == 2) || | |
c1f0c183 MS |
396 | snap_dest) { |
397 | snap->ti->error = "Snapshot cow pairing for exception " | |
398 | "table handover failed"; | |
399 | return -EINVAL; | |
400 | } | |
401 | ||
402 | /* | |
403 | * If no snap_src was found, snap cannot become a handover | |
404 | * destination. | |
405 | */ | |
406 | if (!snap_src) | |
407 | return 0; | |
408 | ||
9d3b15c4 MP |
409 | /* |
410 | * Non-snapshot-merge handover? | |
411 | */ | |
412 | if (!dm_target_is_snapshot_merge(snap->ti)) | |
413 | return 1; | |
414 | ||
415 | /* | |
416 | * Do not allow more than one merging snapshot. | |
417 | */ | |
418 | if (snap_merge) { | |
419 | snap->ti->error = "A snapshot is already merging."; | |
420 | return -EINVAL; | |
421 | } | |
422 | ||
1e03f97e MP |
423 | if (!snap_src->store->type->prepare_merge || |
424 | !snap_src->store->type->commit_merge) { | |
425 | snap->ti->error = "Snapshot exception store does not " | |
426 | "support snapshot-merge."; | |
427 | return -EINVAL; | |
428 | } | |
429 | ||
c1f0c183 MS |
430 | return 1; |
431 | } | |
432 | ||
433 | static void __insert_snapshot(struct origin *o, struct dm_snapshot *s) | |
434 | { | |
435 | struct dm_snapshot *l; | |
436 | ||
437 | /* Sort the list according to chunk size, largest-first smallest-last */ | |
438 | list_for_each_entry(l, &o->snapshots, list) | |
439 | if (l->store->chunk_size < s->store->chunk_size) | |
440 | break; | |
441 | list_add_tail(&s->list, &l->list); | |
442 | } | |
443 | ||
1da177e4 LT |
444 | /* |
445 | * Make a note of the snapshot and its origin so we can look it | |
446 | * up when the origin has a write on it. | |
c1f0c183 MS |
447 | * |
448 | * Also validate snapshot exception store handovers. | |
449 | * On success, returns 1 if this registration is a handover destination, | |
450 | * otherwise returns 0. | |
1da177e4 LT |
451 | */ |
452 | static int register_snapshot(struct dm_snapshot *snap) | |
453 | { | |
c1f0c183 | 454 | struct origin *o, *new_o = NULL; |
1da177e4 | 455 | struct block_device *bdev = snap->origin->bdev; |
c1f0c183 | 456 | int r = 0; |
1da177e4 | 457 | |
60c856c8 MP |
458 | new_o = kmalloc(sizeof(*new_o), GFP_KERNEL); |
459 | if (!new_o) | |
460 | return -ENOMEM; | |
461 | ||
1da177e4 | 462 | down_write(&_origins_lock); |
1da177e4 | 463 | |
c1f0c183 MS |
464 | r = __validate_exception_handover(snap); |
465 | if (r < 0) { | |
466 | kfree(new_o); | |
467 | goto out; | |
468 | } | |
469 | ||
470 | o = __lookup_origin(bdev); | |
60c856c8 MP |
471 | if (o) |
472 | kfree(new_o); | |
473 | else { | |
1da177e4 | 474 | /* New origin */ |
60c856c8 | 475 | o = new_o; |
1da177e4 LT |
476 | |
477 | /* Initialise the struct */ | |
478 | INIT_LIST_HEAD(&o->snapshots); | |
479 | o->bdev = bdev; | |
480 | ||
481 | __insert_origin(o); | |
482 | } | |
483 | ||
c1f0c183 MS |
484 | __insert_snapshot(o, snap); |
485 | ||
486 | out: | |
487 | up_write(&_origins_lock); | |
488 | ||
489 | return r; | |
490 | } | |
491 | ||
492 | /* | |
493 | * Move snapshot to correct place in list according to chunk size. | |
494 | */ | |
495 | static void reregister_snapshot(struct dm_snapshot *s) | |
496 | { | |
497 | struct block_device *bdev = s->origin->bdev; | |
498 | ||
499 | down_write(&_origins_lock); | |
500 | ||
501 | list_del(&s->list); | |
502 | __insert_snapshot(__lookup_origin(bdev), s); | |
1da177e4 LT |
503 | |
504 | up_write(&_origins_lock); | |
1da177e4 LT |
505 | } |
506 | ||
507 | static void unregister_snapshot(struct dm_snapshot *s) | |
508 | { | |
509 | struct origin *o; | |
510 | ||
511 | down_write(&_origins_lock); | |
512 | o = __lookup_origin(s->origin->bdev); | |
513 | ||
514 | list_del(&s->list); | |
c1f0c183 | 515 | if (o && list_empty(&o->snapshots)) { |
1da177e4 LT |
516 | list_del(&o->hash_list); |
517 | kfree(o); | |
518 | } | |
519 | ||
520 | up_write(&_origins_lock); | |
521 | } | |
522 | ||
523 | /* | |
524 | * Implementation of the exception hash tables. | |
d74f81f8 MB |
525 | * The lowest hash_shift bits of the chunk number are ignored, allowing |
526 | * some consecutive chunks to be grouped together. | |
1da177e4 | 527 | */ |
3510cb94 JB |
528 | static int dm_exception_table_init(struct dm_exception_table *et, |
529 | uint32_t size, unsigned hash_shift) | |
1da177e4 LT |
530 | { |
531 | unsigned int i; | |
532 | ||
d74f81f8 | 533 | et->hash_shift = hash_shift; |
1da177e4 LT |
534 | et->hash_mask = size - 1; |
535 | et->table = dm_vcalloc(size, sizeof(struct list_head)); | |
536 | if (!et->table) | |
537 | return -ENOMEM; | |
538 | ||
539 | for (i = 0; i < size; i++) | |
540 | INIT_LIST_HEAD(et->table + i); | |
541 | ||
542 | return 0; | |
543 | } | |
544 | ||
3510cb94 JB |
545 | static void dm_exception_table_exit(struct dm_exception_table *et, |
546 | struct kmem_cache *mem) | |
1da177e4 LT |
547 | { |
548 | struct list_head *slot; | |
1d4989c8 | 549 | struct dm_exception *ex, *next; |
1da177e4 LT |
550 | int i, size; |
551 | ||
552 | size = et->hash_mask + 1; | |
553 | for (i = 0; i < size; i++) { | |
554 | slot = et->table + i; | |
555 | ||
556 | list_for_each_entry_safe (ex, next, slot, hash_list) | |
557 | kmem_cache_free(mem, ex); | |
558 | } | |
559 | ||
560 | vfree(et->table); | |
561 | } | |
562 | ||
191437a5 | 563 | static uint32_t exception_hash(struct dm_exception_table *et, chunk_t chunk) |
1da177e4 | 564 | { |
d74f81f8 | 565 | return (chunk >> et->hash_shift) & et->hash_mask; |
1da177e4 LT |
566 | } |
567 | ||
3510cb94 | 568 | static void dm_remove_exception(struct dm_exception *e) |
1da177e4 LT |
569 | { |
570 | list_del(&e->hash_list); | |
571 | } | |
572 | ||
573 | /* | |
574 | * Return the exception data for a sector, or NULL if not | |
575 | * remapped. | |
576 | */ | |
3510cb94 JB |
577 | static struct dm_exception *dm_lookup_exception(struct dm_exception_table *et, |
578 | chunk_t chunk) | |
1da177e4 LT |
579 | { |
580 | struct list_head *slot; | |
1d4989c8 | 581 | struct dm_exception *e; |
1da177e4 LT |
582 | |
583 | slot = &et->table[exception_hash(et, chunk)]; | |
584 | list_for_each_entry (e, slot, hash_list) | |
d74f81f8 MB |
585 | if (chunk >= e->old_chunk && |
586 | chunk <= e->old_chunk + dm_consecutive_chunk_count(e)) | |
1da177e4 LT |
587 | return e; |
588 | ||
589 | return NULL; | |
590 | } | |
591 | ||
3510cb94 | 592 | static struct dm_exception *alloc_completed_exception(void) |
1da177e4 | 593 | { |
1d4989c8 | 594 | struct dm_exception *e; |
1da177e4 LT |
595 | |
596 | e = kmem_cache_alloc(exception_cache, GFP_NOIO); | |
597 | if (!e) | |
598 | e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); | |
599 | ||
600 | return e; | |
601 | } | |
602 | ||
3510cb94 | 603 | static void free_completed_exception(struct dm_exception *e) |
1da177e4 LT |
604 | { |
605 | kmem_cache_free(exception_cache, e); | |
606 | } | |
607 | ||
92e86812 | 608 | static struct dm_snap_pending_exception *alloc_pending_exception(struct dm_snapshot *s) |
1da177e4 | 609 | { |
92e86812 MP |
610 | struct dm_snap_pending_exception *pe = mempool_alloc(s->pending_pool, |
611 | GFP_NOIO); | |
612 | ||
879129d2 | 613 | atomic_inc(&s->pending_exceptions_count); |
92e86812 MP |
614 | pe->snap = s; |
615 | ||
616 | return pe; | |
1da177e4 LT |
617 | } |
618 | ||
028867ac | 619 | static void free_pending_exception(struct dm_snap_pending_exception *pe) |
1da177e4 | 620 | { |
879129d2 MP |
621 | struct dm_snapshot *s = pe->snap; |
622 | ||
623 | mempool_free(pe, s->pending_pool); | |
624 | smp_mb__before_atomic_dec(); | |
625 | atomic_dec(&s->pending_exceptions_count); | |
1da177e4 LT |
626 | } |
627 | ||
3510cb94 JB |
628 | static void dm_insert_exception(struct dm_exception_table *eh, |
629 | struct dm_exception *new_e) | |
d74f81f8 | 630 | { |
d74f81f8 | 631 | struct list_head *l; |
1d4989c8 | 632 | struct dm_exception *e = NULL; |
d74f81f8 MB |
633 | |
634 | l = &eh->table[exception_hash(eh, new_e->old_chunk)]; | |
635 | ||
636 | /* Add immediately if this table doesn't support consecutive chunks */ | |
637 | if (!eh->hash_shift) | |
638 | goto out; | |
639 | ||
640 | /* List is ordered by old_chunk */ | |
641 | list_for_each_entry_reverse(e, l, hash_list) { | |
642 | /* Insert after an existing chunk? */ | |
643 | if (new_e->old_chunk == (e->old_chunk + | |
644 | dm_consecutive_chunk_count(e) + 1) && | |
645 | new_e->new_chunk == (dm_chunk_number(e->new_chunk) + | |
646 | dm_consecutive_chunk_count(e) + 1)) { | |
647 | dm_consecutive_chunk_count_inc(e); | |
3510cb94 | 648 | free_completed_exception(new_e); |
d74f81f8 MB |
649 | return; |
650 | } | |
651 | ||
652 | /* Insert before an existing chunk? */ | |
653 | if (new_e->old_chunk == (e->old_chunk - 1) && | |
654 | new_e->new_chunk == (dm_chunk_number(e->new_chunk) - 1)) { | |
655 | dm_consecutive_chunk_count_inc(e); | |
656 | e->old_chunk--; | |
657 | e->new_chunk--; | |
3510cb94 | 658 | free_completed_exception(new_e); |
d74f81f8 MB |
659 | return; |
660 | } | |
661 | ||
662 | if (new_e->old_chunk > e->old_chunk) | |
663 | break; | |
664 | } | |
665 | ||
666 | out: | |
667 | list_add(&new_e->hash_list, e ? &e->hash_list : l); | |
668 | } | |
669 | ||
a159c1ac JB |
670 | /* |
671 | * Callback used by the exception stores to load exceptions when | |
672 | * initialising. | |
673 | */ | |
674 | static int dm_add_exception(void *context, chunk_t old, chunk_t new) | |
1da177e4 | 675 | { |
a159c1ac | 676 | struct dm_snapshot *s = context; |
1d4989c8 | 677 | struct dm_exception *e; |
1da177e4 | 678 | |
3510cb94 | 679 | e = alloc_completed_exception(); |
1da177e4 LT |
680 | if (!e) |
681 | return -ENOMEM; | |
682 | ||
683 | e->old_chunk = old; | |
d74f81f8 MB |
684 | |
685 | /* Consecutive_count is implicitly initialised to zero */ | |
1da177e4 | 686 | e->new_chunk = new; |
d74f81f8 | 687 | |
3510cb94 | 688 | dm_insert_exception(&s->complete, e); |
d74f81f8 | 689 | |
1da177e4 LT |
690 | return 0; |
691 | } | |
692 | ||
7e201b35 MP |
693 | /* |
694 | * Return a minimum chunk size of all snapshots that have the specified origin. | |
695 | * Return zero if the origin has no snapshots. | |
696 | */ | |
697 | static sector_t __minimum_chunk_size(struct origin *o) | |
698 | { | |
699 | struct dm_snapshot *snap; | |
700 | unsigned chunk_size = 0; | |
701 | ||
702 | if (o) | |
703 | list_for_each_entry(snap, &o->snapshots, list) | |
704 | chunk_size = min_not_zero(chunk_size, | |
705 | snap->store->chunk_size); | |
706 | ||
707 | return chunk_size; | |
708 | } | |
709 | ||
1da177e4 LT |
710 | /* |
711 | * Hard coded magic. | |
712 | */ | |
713 | static int calc_max_buckets(void) | |
714 | { | |
715 | /* use a fixed size of 2MB */ | |
716 | unsigned long mem = 2 * 1024 * 1024; | |
717 | mem /= sizeof(struct list_head); | |
718 | ||
719 | return mem; | |
720 | } | |
721 | ||
1da177e4 LT |
722 | /* |
723 | * Allocate room for a suitable hash table. | |
724 | */ | |
fee1998e | 725 | static int init_hash_tables(struct dm_snapshot *s) |
1da177e4 LT |
726 | { |
727 | sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; | |
728 | ||
729 | /* | |
730 | * Calculate based on the size of the original volume or | |
731 | * the COW volume... | |
732 | */ | |
fc56f6fb | 733 | cow_dev_size = get_dev_size(s->cow->bdev); |
1da177e4 LT |
734 | origin_dev_size = get_dev_size(s->origin->bdev); |
735 | max_buckets = calc_max_buckets(); | |
736 | ||
fee1998e | 737 | hash_size = min(origin_dev_size, cow_dev_size) >> s->store->chunk_shift; |
1da177e4 LT |
738 | hash_size = min(hash_size, max_buckets); |
739 | ||
8e87b9b8 MP |
740 | if (hash_size < 64) |
741 | hash_size = 64; | |
8defd830 | 742 | hash_size = rounddown_pow_of_two(hash_size); |
3510cb94 JB |
743 | if (dm_exception_table_init(&s->complete, hash_size, |
744 | DM_CHUNK_CONSECUTIVE_BITS)) | |
1da177e4 LT |
745 | return -ENOMEM; |
746 | ||
747 | /* | |
748 | * Allocate hash table for in-flight exceptions | |
749 | * Make this smaller than the real hash table | |
750 | */ | |
751 | hash_size >>= 3; | |
752 | if (hash_size < 64) | |
753 | hash_size = 64; | |
754 | ||
3510cb94 JB |
755 | if (dm_exception_table_init(&s->pending, hash_size, 0)) { |
756 | dm_exception_table_exit(&s->complete, exception_cache); | |
1da177e4 LT |
757 | return -ENOMEM; |
758 | } | |
759 | ||
760 | return 0; | |
761 | } | |
762 | ||
1e03f97e MP |
763 | static void merge_shutdown(struct dm_snapshot *s) |
764 | { | |
765 | clear_bit_unlock(RUNNING_MERGE, &s->state_bits); | |
766 | smp_mb__after_clear_bit(); | |
767 | wake_up_bit(&s->state_bits, RUNNING_MERGE); | |
768 | } | |
769 | ||
9fe86254 MP |
770 | static struct bio *__release_queued_bios_after_merge(struct dm_snapshot *s) |
771 | { | |
772 | s->first_merging_chunk = 0; | |
773 | s->num_merging_chunks = 0; | |
774 | ||
775 | return bio_list_get(&s->bios_queued_during_merge); | |
776 | } | |
777 | ||
1e03f97e MP |
778 | /* |
779 | * Remove one chunk from the index of completed exceptions. | |
780 | */ | |
781 | static int __remove_single_exception_chunk(struct dm_snapshot *s, | |
782 | chunk_t old_chunk) | |
783 | { | |
784 | struct dm_exception *e; | |
785 | ||
1e03f97e MP |
786 | e = dm_lookup_exception(&s->complete, old_chunk); |
787 | if (!e) { | |
788 | DMERR("Corruption detected: exception for block %llu is " | |
789 | "on disk but not in memory", | |
790 | (unsigned long long)old_chunk); | |
791 | return -EINVAL; | |
792 | } | |
793 | ||
794 | /* | |
795 | * If this is the only chunk using this exception, remove exception. | |
796 | */ | |
797 | if (!dm_consecutive_chunk_count(e)) { | |
798 | dm_remove_exception(e); | |
799 | free_completed_exception(e); | |
800 | return 0; | |
801 | } | |
802 | ||
803 | /* | |
804 | * The chunk may be either at the beginning or the end of a | |
805 | * group of consecutive chunks - never in the middle. We are | |
806 | * removing chunks in the opposite order to that in which they | |
807 | * were added, so this should always be true. | |
808 | * Decrement the consecutive chunk counter and adjust the | |
809 | * starting point if necessary. | |
810 | */ | |
811 | if (old_chunk == e->old_chunk) { | |
812 | e->old_chunk++; | |
813 | e->new_chunk++; | |
814 | } else if (old_chunk != e->old_chunk + | |
815 | dm_consecutive_chunk_count(e)) { | |
816 | DMERR("Attempt to merge block %llu from the " | |
817 | "middle of a chunk range [%llu - %llu]", | |
818 | (unsigned long long)old_chunk, | |
819 | (unsigned long long)e->old_chunk, | |
820 | (unsigned long long) | |
821 | e->old_chunk + dm_consecutive_chunk_count(e)); | |
822 | return -EINVAL; | |
823 | } | |
824 | ||
825 | dm_consecutive_chunk_count_dec(e); | |
826 | ||
827 | return 0; | |
828 | } | |
829 | ||
9fe86254 MP |
830 | static void flush_bios(struct bio *bio); |
831 | ||
832 | static int remove_single_exception_chunk(struct dm_snapshot *s) | |
1e03f97e | 833 | { |
9fe86254 MP |
834 | struct bio *b = NULL; |
835 | int r; | |
836 | chunk_t old_chunk = s->first_merging_chunk + s->num_merging_chunks - 1; | |
1e03f97e MP |
837 | |
838 | down_write(&s->lock); | |
9fe86254 MP |
839 | |
840 | /* | |
841 | * Process chunks (and associated exceptions) in reverse order | |
842 | * so that dm_consecutive_chunk_count_dec() accounting works. | |
843 | */ | |
844 | do { | |
845 | r = __remove_single_exception_chunk(s, old_chunk); | |
846 | if (r) | |
847 | goto out; | |
848 | } while (old_chunk-- > s->first_merging_chunk); | |
849 | ||
850 | b = __release_queued_bios_after_merge(s); | |
851 | ||
852 | out: | |
1e03f97e | 853 | up_write(&s->lock); |
9fe86254 MP |
854 | if (b) |
855 | flush_bios(b); | |
1e03f97e MP |
856 | |
857 | return r; | |
858 | } | |
859 | ||
73dfd078 MP |
860 | static int origin_write_extent(struct dm_snapshot *merging_snap, |
861 | sector_t sector, unsigned chunk_size); | |
862 | ||
1e03f97e MP |
863 | static void merge_callback(int read_err, unsigned long write_err, |
864 | void *context); | |
865 | ||
73dfd078 MP |
866 | static uint64_t read_pending_exceptions_done_count(void) |
867 | { | |
868 | uint64_t pending_exceptions_done; | |
869 | ||
870 | spin_lock(&_pending_exceptions_done_spinlock); | |
871 | pending_exceptions_done = _pending_exceptions_done_count; | |
872 | spin_unlock(&_pending_exceptions_done_spinlock); | |
873 | ||
874 | return pending_exceptions_done; | |
875 | } | |
876 | ||
877 | static void increment_pending_exceptions_done_count(void) | |
878 | { | |
879 | spin_lock(&_pending_exceptions_done_spinlock); | |
880 | _pending_exceptions_done_count++; | |
881 | spin_unlock(&_pending_exceptions_done_spinlock); | |
882 | ||
883 | wake_up_all(&_pending_exceptions_done); | |
884 | } | |
885 | ||
1e03f97e MP |
886 | static void snapshot_merge_next_chunks(struct dm_snapshot *s) |
887 | { | |
8a2d5286 | 888 | int i, linear_chunks; |
1e03f97e MP |
889 | chunk_t old_chunk, new_chunk; |
890 | struct dm_io_region src, dest; | |
8a2d5286 | 891 | sector_t io_size; |
73dfd078 | 892 | uint64_t previous_count; |
1e03f97e MP |
893 | |
894 | BUG_ON(!test_bit(RUNNING_MERGE, &s->state_bits)); | |
895 | if (unlikely(test_bit(SHUTDOWN_MERGE, &s->state_bits))) | |
896 | goto shut; | |
897 | ||
898 | /* | |
899 | * valid flag never changes during merge, so no lock required. | |
900 | */ | |
901 | if (!s->valid) { | |
902 | DMERR("Snapshot is invalid: can't merge"); | |
903 | goto shut; | |
904 | } | |
905 | ||
8a2d5286 MS |
906 | linear_chunks = s->store->type->prepare_merge(s->store, &old_chunk, |
907 | &new_chunk); | |
908 | if (linear_chunks <= 0) { | |
d8ddb1cf | 909 | if (linear_chunks < 0) { |
1e03f97e MP |
910 | DMERR("Read error in exception store: " |
911 | "shutting down merge"); | |
d8ddb1cf MS |
912 | down_write(&s->lock); |
913 | s->merge_failed = 1; | |
914 | up_write(&s->lock); | |
915 | } | |
1e03f97e MP |
916 | goto shut; |
917 | } | |
918 | ||
8a2d5286 MS |
919 | /* Adjust old_chunk and new_chunk to reflect start of linear region */ |
920 | old_chunk = old_chunk + 1 - linear_chunks; | |
921 | new_chunk = new_chunk + 1 - linear_chunks; | |
922 | ||
923 | /* | |
924 | * Use one (potentially large) I/O to copy all 'linear_chunks' | |
925 | * from the exception store to the origin | |
926 | */ | |
927 | io_size = linear_chunks * s->store->chunk_size; | |
1e03f97e | 928 | |
1e03f97e MP |
929 | dest.bdev = s->origin->bdev; |
930 | dest.sector = chunk_to_sector(s->store, old_chunk); | |
8a2d5286 | 931 | dest.count = min(io_size, get_dev_size(dest.bdev) - dest.sector); |
1e03f97e MP |
932 | |
933 | src.bdev = s->cow->bdev; | |
934 | src.sector = chunk_to_sector(s->store, new_chunk); | |
935 | src.count = dest.count; | |
936 | ||
73dfd078 MP |
937 | /* |
938 | * Reallocate any exceptions needed in other snapshots then | |
939 | * wait for the pending exceptions to complete. | |
940 | * Each time any pending exception (globally on the system) | |
941 | * completes we are woken and repeat the process to find out | |
942 | * if we can proceed. While this may not seem a particularly | |
943 | * efficient algorithm, it is not expected to have any | |
944 | * significant impact on performance. | |
945 | */ | |
946 | previous_count = read_pending_exceptions_done_count(); | |
8a2d5286 | 947 | while (origin_write_extent(s, dest.sector, io_size)) { |
73dfd078 MP |
948 | wait_event(_pending_exceptions_done, |
949 | (read_pending_exceptions_done_count() != | |
950 | previous_count)); | |
951 | /* Retry after the wait, until all exceptions are done. */ | |
952 | previous_count = read_pending_exceptions_done_count(); | |
953 | } | |
954 | ||
9fe86254 MP |
955 | down_write(&s->lock); |
956 | s->first_merging_chunk = old_chunk; | |
8a2d5286 | 957 | s->num_merging_chunks = linear_chunks; |
9fe86254 MP |
958 | up_write(&s->lock); |
959 | ||
8a2d5286 MS |
960 | /* Wait until writes to all 'linear_chunks' drain */ |
961 | for (i = 0; i < linear_chunks; i++) | |
962 | __check_for_conflicting_io(s, old_chunk + i); | |
9fe86254 | 963 | |
1e03f97e MP |
964 | dm_kcopyd_copy(s->kcopyd_client, &src, 1, &dest, 0, merge_callback, s); |
965 | return; | |
966 | ||
967 | shut: | |
968 | merge_shutdown(s); | |
969 | } | |
970 | ||
9fe86254 MP |
971 | static void error_bios(struct bio *bio); |
972 | ||
1e03f97e MP |
973 | static void merge_callback(int read_err, unsigned long write_err, void *context) |
974 | { | |
975 | struct dm_snapshot *s = context; | |
9fe86254 | 976 | struct bio *b = NULL; |
1e03f97e MP |
977 | |
978 | if (read_err || write_err) { | |
979 | if (read_err) | |
980 | DMERR("Read error: shutting down merge."); | |
981 | else | |
982 | DMERR("Write error: shutting down merge."); | |
983 | goto shut; | |
984 | } | |
985 | ||
9fe86254 MP |
986 | if (s->store->type->commit_merge(s->store, |
987 | s->num_merging_chunks) < 0) { | |
1e03f97e MP |
988 | DMERR("Write error in exception store: shutting down merge"); |
989 | goto shut; | |
990 | } | |
991 | ||
9fe86254 MP |
992 | if (remove_single_exception_chunk(s) < 0) |
993 | goto shut; | |
994 | ||
1e03f97e MP |
995 | snapshot_merge_next_chunks(s); |
996 | ||
997 | return; | |
998 | ||
999 | shut: | |
9fe86254 | 1000 | down_write(&s->lock); |
d8ddb1cf | 1001 | s->merge_failed = 1; |
9fe86254 MP |
1002 | b = __release_queued_bios_after_merge(s); |
1003 | up_write(&s->lock); | |
1004 | error_bios(b); | |
1005 | ||
1e03f97e MP |
1006 | merge_shutdown(s); |
1007 | } | |
1008 | ||
1009 | static void start_merge(struct dm_snapshot *s) | |
1010 | { | |
1011 | if (!test_and_set_bit(RUNNING_MERGE, &s->state_bits)) | |
1012 | snapshot_merge_next_chunks(s); | |
1013 | } | |
1014 | ||
1015 | static int wait_schedule(void *ptr) | |
1016 | { | |
1017 | schedule(); | |
1018 | ||
1019 | return 0; | |
1020 | } | |
1021 | ||
1022 | /* | |
1023 | * Stop the merging process and wait until it finishes. | |
1024 | */ | |
1025 | static void stop_merge(struct dm_snapshot *s) | |
1026 | { | |
1027 | set_bit(SHUTDOWN_MERGE, &s->state_bits); | |
1028 | wait_on_bit(&s->state_bits, RUNNING_MERGE, wait_schedule, | |
1029 | TASK_UNINTERRUPTIBLE); | |
1030 | clear_bit(SHUTDOWN_MERGE, &s->state_bits); | |
1031 | } | |
1032 | ||
1da177e4 LT |
1033 | /* |
1034 | * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> | |
1035 | */ | |
1036 | static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
1037 | { | |
1038 | struct dm_snapshot *s; | |
cd45daff | 1039 | int i; |
1da177e4 | 1040 | int r = -EINVAL; |
fc56f6fb | 1041 | char *origin_path, *cow_path; |
10b8106a MS |
1042 | unsigned args_used, num_flush_requests = 1; |
1043 | fmode_t origin_mode = FMODE_READ; | |
1da177e4 | 1044 | |
4c7e3bf4 | 1045 | if (argc != 4) { |
72d94861 | 1046 | ti->error = "requires exactly 4 arguments"; |
1da177e4 | 1047 | r = -EINVAL; |
fc56f6fb | 1048 | goto bad; |
1da177e4 LT |
1049 | } |
1050 | ||
10b8106a MS |
1051 | if (dm_target_is_snapshot_merge(ti)) { |
1052 | num_flush_requests = 2; | |
1053 | origin_mode = FMODE_WRITE; | |
1054 | } | |
1055 | ||
fc56f6fb MS |
1056 | s = kmalloc(sizeof(*s), GFP_KERNEL); |
1057 | if (!s) { | |
1058 | ti->error = "Cannot allocate snapshot context private " | |
1059 | "structure"; | |
1060 | r = -ENOMEM; | |
1061 | goto bad; | |
1062 | } | |
1063 | ||
c2411045 MP |
1064 | origin_path = argv[0]; |
1065 | argv++; | |
1066 | argc--; | |
1067 | ||
1068 | r = dm_get_device(ti, origin_path, origin_mode, &s->origin); | |
1069 | if (r) { | |
1070 | ti->error = "Cannot get origin device"; | |
1071 | goto bad_origin; | |
1072 | } | |
1073 | ||
fc56f6fb MS |
1074 | cow_path = argv[0]; |
1075 | argv++; | |
1076 | argc--; | |
1077 | ||
024d37e9 | 1078 | r = dm_get_device(ti, cow_path, dm_table_get_mode(ti->table), &s->cow); |
fc56f6fb MS |
1079 | if (r) { |
1080 | ti->error = "Cannot get COW device"; | |
1081 | goto bad_cow; | |
1082 | } | |
1083 | ||
1084 | r = dm_exception_store_create(ti, argc, argv, s, &args_used, &s->store); | |
fee1998e JB |
1085 | if (r) { |
1086 | ti->error = "Couldn't create exception store"; | |
1da177e4 | 1087 | r = -EINVAL; |
fc56f6fb | 1088 | goto bad_store; |
1da177e4 LT |
1089 | } |
1090 | ||
fee1998e JB |
1091 | argv += args_used; |
1092 | argc -= args_used; | |
1093 | ||
fc56f6fb | 1094 | s->ti = ti; |
1da177e4 | 1095 | s->valid = 1; |
aa14edeb | 1096 | s->active = 0; |
879129d2 | 1097 | atomic_set(&s->pending_exceptions_count, 0); |
1da177e4 | 1098 | init_rwsem(&s->lock); |
c1f0c183 | 1099 | INIT_LIST_HEAD(&s->list); |
ca3a931f | 1100 | spin_lock_init(&s->pe_lock); |
1e03f97e | 1101 | s->state_bits = 0; |
d8ddb1cf | 1102 | s->merge_failed = 0; |
9fe86254 MP |
1103 | s->first_merging_chunk = 0; |
1104 | s->num_merging_chunks = 0; | |
1105 | bio_list_init(&s->bios_queued_during_merge); | |
1da177e4 LT |
1106 | |
1107 | /* Allocate hash table for COW data */ | |
fee1998e | 1108 | if (init_hash_tables(s)) { |
1da177e4 LT |
1109 | ti->error = "Unable to allocate hash table space"; |
1110 | r = -ENOMEM; | |
fee1998e | 1111 | goto bad_hash_tables; |
1da177e4 LT |
1112 | } |
1113 | ||
fa34ce73 MP |
1114 | s->kcopyd_client = dm_kcopyd_client_create(); |
1115 | if (IS_ERR(s->kcopyd_client)) { | |
1116 | r = PTR_ERR(s->kcopyd_client); | |
1da177e4 | 1117 | ti->error = "Could not create kcopyd client"; |
fee1998e | 1118 | goto bad_kcopyd; |
1da177e4 LT |
1119 | } |
1120 | ||
92e86812 MP |
1121 | s->pending_pool = mempool_create_slab_pool(MIN_IOS, pending_cache); |
1122 | if (!s->pending_pool) { | |
1123 | ti->error = "Could not allocate mempool for pending exceptions"; | |
fee1998e | 1124 | goto bad_pending_pool; |
92e86812 MP |
1125 | } |
1126 | ||
cd45daff MP |
1127 | s->tracked_chunk_pool = mempool_create_slab_pool(MIN_IOS, |
1128 | tracked_chunk_cache); | |
1129 | if (!s->tracked_chunk_pool) { | |
1130 | ti->error = "Could not allocate tracked_chunk mempool for " | |
1131 | "tracking reads"; | |
92e86812 | 1132 | goto bad_tracked_chunk_pool; |
cd45daff MP |
1133 | } |
1134 | ||
1135 | for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) | |
1136 | INIT_HLIST_HEAD(&s->tracked_chunk_hash[i]); | |
1137 | ||
1138 | spin_lock_init(&s->tracked_chunk_lock); | |
1139 | ||
c1f0c183 | 1140 | ti->private = s; |
10b8106a | 1141 | ti->num_flush_requests = num_flush_requests; |
c1f0c183 MS |
1142 | |
1143 | /* Add snapshot to the list of snapshots for this origin */ | |
1144 | /* Exceptions aren't triggered till snapshot_resume() is called */ | |
1145 | r = register_snapshot(s); | |
1146 | if (r == -ENOMEM) { | |
1147 | ti->error = "Snapshot origin struct allocation failed"; | |
1148 | goto bad_load_and_register; | |
1149 | } else if (r < 0) { | |
1150 | /* invalid handover, register_snapshot has set ti->error */ | |
1151 | goto bad_load_and_register; | |
1152 | } | |
1153 | ||
1154 | /* | |
1155 | * Metadata must only be loaded into one table at once, so skip this | |
1156 | * if metadata will be handed over during resume. | |
1157 | * Chunk size will be set during the handover - set it to zero to | |
1158 | * ensure it's ignored. | |
1159 | */ | |
1160 | if (r > 0) { | |
1161 | s->store->chunk_size = 0; | |
1162 | return 0; | |
1163 | } | |
1164 | ||
493df71c JB |
1165 | r = s->store->type->read_metadata(s->store, dm_add_exception, |
1166 | (void *)s); | |
0764147b | 1167 | if (r < 0) { |
f9cea4f7 | 1168 | ti->error = "Failed to read snapshot metadata"; |
c1f0c183 | 1169 | goto bad_read_metadata; |
0764147b MB |
1170 | } else if (r > 0) { |
1171 | s->valid = 0; | |
1172 | DMWARN("Snapshot is marked invalid."); | |
f9cea4f7 | 1173 | } |
aa14edeb | 1174 | |
3f2412dc MP |
1175 | if (!s->store->chunk_size) { |
1176 | ti->error = "Chunk size not set"; | |
c1f0c183 | 1177 | goto bad_read_metadata; |
1da177e4 | 1178 | } |
d0216849 | 1179 | ti->split_io = s->store->chunk_size; |
1da177e4 LT |
1180 | |
1181 | return 0; | |
1182 | ||
c1f0c183 MS |
1183 | bad_read_metadata: |
1184 | unregister_snapshot(s); | |
1185 | ||
fee1998e | 1186 | bad_load_and_register: |
cd45daff MP |
1187 | mempool_destroy(s->tracked_chunk_pool); |
1188 | ||
fee1998e | 1189 | bad_tracked_chunk_pool: |
92e86812 MP |
1190 | mempool_destroy(s->pending_pool); |
1191 | ||
fee1998e | 1192 | bad_pending_pool: |
eb69aca5 | 1193 | dm_kcopyd_client_destroy(s->kcopyd_client); |
1da177e4 | 1194 | |
fee1998e | 1195 | bad_kcopyd: |
3510cb94 JB |
1196 | dm_exception_table_exit(&s->pending, pending_cache); |
1197 | dm_exception_table_exit(&s->complete, exception_cache); | |
1da177e4 | 1198 | |
fee1998e | 1199 | bad_hash_tables: |
fc56f6fb | 1200 | dm_exception_store_destroy(s->store); |
1da177e4 | 1201 | |
fc56f6fb MS |
1202 | bad_store: |
1203 | dm_put_device(ti, s->cow); | |
fee1998e | 1204 | |
fc56f6fb | 1205 | bad_cow: |
c2411045 MP |
1206 | dm_put_device(ti, s->origin); |
1207 | ||
1208 | bad_origin: | |
fc56f6fb MS |
1209 | kfree(s); |
1210 | ||
1211 | bad: | |
1da177e4 LT |
1212 | return r; |
1213 | } | |
1214 | ||
31c93a0c MB |
1215 | static void __free_exceptions(struct dm_snapshot *s) |
1216 | { | |
eb69aca5 | 1217 | dm_kcopyd_client_destroy(s->kcopyd_client); |
31c93a0c MB |
1218 | s->kcopyd_client = NULL; |
1219 | ||
3510cb94 JB |
1220 | dm_exception_table_exit(&s->pending, pending_cache); |
1221 | dm_exception_table_exit(&s->complete, exception_cache); | |
31c93a0c MB |
1222 | } |
1223 | ||
c1f0c183 MS |
1224 | static void __handover_exceptions(struct dm_snapshot *snap_src, |
1225 | struct dm_snapshot *snap_dest) | |
1226 | { | |
1227 | union { | |
1228 | struct dm_exception_table table_swap; | |
1229 | struct dm_exception_store *store_swap; | |
1230 | } u; | |
1231 | ||
1232 | /* | |
1233 | * Swap all snapshot context information between the two instances. | |
1234 | */ | |
1235 | u.table_swap = snap_dest->complete; | |
1236 | snap_dest->complete = snap_src->complete; | |
1237 | snap_src->complete = u.table_swap; | |
1238 | ||
1239 | u.store_swap = snap_dest->store; | |
1240 | snap_dest->store = snap_src->store; | |
1241 | snap_src->store = u.store_swap; | |
1242 | ||
1243 | snap_dest->store->snap = snap_dest; | |
1244 | snap_src->store->snap = snap_src; | |
1245 | ||
1246 | snap_dest->ti->split_io = snap_dest->store->chunk_size; | |
1247 | snap_dest->valid = snap_src->valid; | |
1248 | ||
1249 | /* | |
1250 | * Set source invalid to ensure it receives no further I/O. | |
1251 | */ | |
1252 | snap_src->valid = 0; | |
1253 | } | |
1254 | ||
1da177e4 LT |
1255 | static void snapshot_dtr(struct dm_target *ti) |
1256 | { | |
cd45daff MP |
1257 | #ifdef CONFIG_DM_DEBUG |
1258 | int i; | |
1259 | #endif | |
028867ac | 1260 | struct dm_snapshot *s = ti->private; |
c1f0c183 | 1261 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; |
1da177e4 | 1262 | |
c1f0c183 MS |
1263 | down_read(&_origins_lock); |
1264 | /* Check whether exception handover must be cancelled */ | |
9d3b15c4 | 1265 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1266 | if (snap_src && snap_dest && (s == snap_src)) { |
1267 | down_write(&snap_dest->lock); | |
1268 | snap_dest->valid = 0; | |
1269 | up_write(&snap_dest->lock); | |
1270 | DMERR("Cancelling snapshot handover."); | |
1271 | } | |
1272 | up_read(&_origins_lock); | |
1273 | ||
1e03f97e MP |
1274 | if (dm_target_is_snapshot_merge(ti)) |
1275 | stop_merge(s); | |
1276 | ||
138728dc AK |
1277 | /* Prevent further origin writes from using this snapshot. */ |
1278 | /* After this returns there can be no new kcopyd jobs. */ | |
1da177e4 LT |
1279 | unregister_snapshot(s); |
1280 | ||
879129d2 | 1281 | while (atomic_read(&s->pending_exceptions_count)) |
90fa1527 | 1282 | msleep(1); |
879129d2 MP |
1283 | /* |
1284 | * Ensure instructions in mempool_destroy aren't reordered | |
1285 | * before atomic_read. | |
1286 | */ | |
1287 | smp_mb(); | |
1288 | ||
cd45daff MP |
1289 | #ifdef CONFIG_DM_DEBUG |
1290 | for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) | |
1291 | BUG_ON(!hlist_empty(&s->tracked_chunk_hash[i])); | |
1292 | #endif | |
1293 | ||
1294 | mempool_destroy(s->tracked_chunk_pool); | |
1295 | ||
31c93a0c | 1296 | __free_exceptions(s); |
1da177e4 | 1297 | |
92e86812 MP |
1298 | mempool_destroy(s->pending_pool); |
1299 | ||
fee1998e | 1300 | dm_exception_store_destroy(s->store); |
138728dc | 1301 | |
fc56f6fb MS |
1302 | dm_put_device(ti, s->cow); |
1303 | ||
c2411045 MP |
1304 | dm_put_device(ti, s->origin); |
1305 | ||
1da177e4 LT |
1306 | kfree(s); |
1307 | } | |
1308 | ||
1309 | /* | |
1310 | * Flush a list of buffers. | |
1311 | */ | |
1312 | static void flush_bios(struct bio *bio) | |
1313 | { | |
1314 | struct bio *n; | |
1315 | ||
1316 | while (bio) { | |
1317 | n = bio->bi_next; | |
1318 | bio->bi_next = NULL; | |
1319 | generic_make_request(bio); | |
1320 | bio = n; | |
1321 | } | |
1322 | } | |
1323 | ||
515ad66c MP |
1324 | static int do_origin(struct dm_dev *origin, struct bio *bio); |
1325 | ||
1326 | /* | |
1327 | * Flush a list of buffers. | |
1328 | */ | |
1329 | static void retry_origin_bios(struct dm_snapshot *s, struct bio *bio) | |
1330 | { | |
1331 | struct bio *n; | |
1332 | int r; | |
1333 | ||
1334 | while (bio) { | |
1335 | n = bio->bi_next; | |
1336 | bio->bi_next = NULL; | |
1337 | r = do_origin(s->origin, bio); | |
1338 | if (r == DM_MAPIO_REMAPPED) | |
1339 | generic_make_request(bio); | |
1340 | bio = n; | |
1341 | } | |
1342 | } | |
1343 | ||
1da177e4 LT |
1344 | /* |
1345 | * Error a list of buffers. | |
1346 | */ | |
1347 | static void error_bios(struct bio *bio) | |
1348 | { | |
1349 | struct bio *n; | |
1350 | ||
1351 | while (bio) { | |
1352 | n = bio->bi_next; | |
1353 | bio->bi_next = NULL; | |
6712ecf8 | 1354 | bio_io_error(bio); |
1da177e4 LT |
1355 | bio = n; |
1356 | } | |
1357 | } | |
1358 | ||
695368ac | 1359 | static void __invalidate_snapshot(struct dm_snapshot *s, int err) |
76df1c65 AK |
1360 | { |
1361 | if (!s->valid) | |
1362 | return; | |
1363 | ||
1364 | if (err == -EIO) | |
1365 | DMERR("Invalidating snapshot: Error reading/writing."); | |
1366 | else if (err == -ENOMEM) | |
1367 | DMERR("Invalidating snapshot: Unable to allocate exception."); | |
1368 | ||
493df71c JB |
1369 | if (s->store->type->drop_snapshot) |
1370 | s->store->type->drop_snapshot(s->store); | |
76df1c65 AK |
1371 | |
1372 | s->valid = 0; | |
1373 | ||
fc56f6fb | 1374 | dm_table_event(s->ti->table); |
76df1c65 AK |
1375 | } |
1376 | ||
028867ac | 1377 | static void pending_complete(struct dm_snap_pending_exception *pe, int success) |
1da177e4 | 1378 | { |
1d4989c8 | 1379 | struct dm_exception *e; |
1da177e4 | 1380 | struct dm_snapshot *s = pe->snap; |
9d493fa8 AK |
1381 | struct bio *origin_bios = NULL; |
1382 | struct bio *snapshot_bios = NULL; | |
1383 | int error = 0; | |
1da177e4 | 1384 | |
76df1c65 AK |
1385 | if (!success) { |
1386 | /* Read/write error - snapshot is unusable */ | |
1da177e4 | 1387 | down_write(&s->lock); |
695368ac | 1388 | __invalidate_snapshot(s, -EIO); |
9d493fa8 | 1389 | error = 1; |
76df1c65 AK |
1390 | goto out; |
1391 | } | |
1392 | ||
3510cb94 | 1393 | e = alloc_completed_exception(); |
76df1c65 | 1394 | if (!e) { |
1da177e4 | 1395 | down_write(&s->lock); |
695368ac | 1396 | __invalidate_snapshot(s, -ENOMEM); |
9d493fa8 | 1397 | error = 1; |
76df1c65 AK |
1398 | goto out; |
1399 | } | |
1400 | *e = pe->e; | |
1da177e4 | 1401 | |
76df1c65 AK |
1402 | down_write(&s->lock); |
1403 | if (!s->valid) { | |
3510cb94 | 1404 | free_completed_exception(e); |
9d493fa8 | 1405 | error = 1; |
76df1c65 | 1406 | goto out; |
1da177e4 LT |
1407 | } |
1408 | ||
615d1eb9 MS |
1409 | /* Check for conflicting reads */ |
1410 | __check_for_conflicting_io(s, pe->e.old_chunk); | |
a8d41b59 | 1411 | |
9d493fa8 AK |
1412 | /* |
1413 | * Add a proper exception, and remove the | |
1414 | * in-flight exception from the list. | |
1415 | */ | |
3510cb94 | 1416 | dm_insert_exception(&s->complete, e); |
76df1c65 | 1417 | |
1da177e4 | 1418 | out: |
3510cb94 | 1419 | dm_remove_exception(&pe->e); |
9d493fa8 | 1420 | snapshot_bios = bio_list_get(&pe->snapshot_bios); |
515ad66c MP |
1421 | origin_bios = bio_list_get(&pe->origin_bios); |
1422 | free_pending_exception(pe); | |
1da177e4 | 1423 | |
73dfd078 MP |
1424 | increment_pending_exceptions_done_count(); |
1425 | ||
9d493fa8 AK |
1426 | up_write(&s->lock); |
1427 | ||
1428 | /* Submit any pending write bios */ | |
1429 | if (error) | |
1430 | error_bios(snapshot_bios); | |
1431 | else | |
1432 | flush_bios(snapshot_bios); | |
1433 | ||
515ad66c | 1434 | retry_origin_bios(s, origin_bios); |
1da177e4 LT |
1435 | } |
1436 | ||
1437 | static void commit_callback(void *context, int success) | |
1438 | { | |
028867ac AK |
1439 | struct dm_snap_pending_exception *pe = context; |
1440 | ||
1da177e4 LT |
1441 | pending_complete(pe, success); |
1442 | } | |
1443 | ||
1444 | /* | |
1445 | * Called when the copy I/O has finished. kcopyd actually runs | |
1446 | * this code so don't block. | |
1447 | */ | |
4cdc1d1f | 1448 | static void copy_callback(int read_err, unsigned long write_err, void *context) |
1da177e4 | 1449 | { |
028867ac | 1450 | struct dm_snap_pending_exception *pe = context; |
1da177e4 LT |
1451 | struct dm_snapshot *s = pe->snap; |
1452 | ||
1453 | if (read_err || write_err) | |
1454 | pending_complete(pe, 0); | |
1455 | ||
1456 | else | |
1457 | /* Update the metadata if we are persistent */ | |
493df71c JB |
1458 | s->store->type->commit_exception(s->store, &pe->e, |
1459 | commit_callback, pe); | |
1da177e4 LT |
1460 | } |
1461 | ||
1462 | /* | |
1463 | * Dispatches the copy operation to kcopyd. | |
1464 | */ | |
028867ac | 1465 | static void start_copy(struct dm_snap_pending_exception *pe) |
1da177e4 LT |
1466 | { |
1467 | struct dm_snapshot *s = pe->snap; | |
22a1ceb1 | 1468 | struct dm_io_region src, dest; |
1da177e4 LT |
1469 | struct block_device *bdev = s->origin->bdev; |
1470 | sector_t dev_size; | |
1471 | ||
1472 | dev_size = get_dev_size(bdev); | |
1473 | ||
1474 | src.bdev = bdev; | |
71fab00a | 1475 | src.sector = chunk_to_sector(s->store, pe->e.old_chunk); |
df96eee6 | 1476 | src.count = min((sector_t)s->store->chunk_size, dev_size - src.sector); |
1da177e4 | 1477 | |
fc56f6fb | 1478 | dest.bdev = s->cow->bdev; |
71fab00a | 1479 | dest.sector = chunk_to_sector(s->store, pe->e.new_chunk); |
1da177e4 LT |
1480 | dest.count = src.count; |
1481 | ||
1482 | /* Hand over to kcopyd */ | |
eb69aca5 | 1483 | dm_kcopyd_copy(s->kcopyd_client, |
1da177e4 LT |
1484 | &src, 1, &dest, 0, copy_callback, pe); |
1485 | } | |
1486 | ||
2913808e MP |
1487 | static struct dm_snap_pending_exception * |
1488 | __lookup_pending_exception(struct dm_snapshot *s, chunk_t chunk) | |
1489 | { | |
3510cb94 | 1490 | struct dm_exception *e = dm_lookup_exception(&s->pending, chunk); |
2913808e MP |
1491 | |
1492 | if (!e) | |
1493 | return NULL; | |
1494 | ||
1495 | return container_of(e, struct dm_snap_pending_exception, e); | |
1496 | } | |
1497 | ||
1da177e4 LT |
1498 | /* |
1499 | * Looks to see if this snapshot already has a pending exception | |
1500 | * for this chunk, otherwise it allocates a new one and inserts | |
1501 | * it into the pending table. | |
1502 | * | |
1503 | * NOTE: a write lock must be held on snap->lock before calling | |
1504 | * this. | |
1505 | */ | |
028867ac | 1506 | static struct dm_snap_pending_exception * |
c6621392 MP |
1507 | __find_pending_exception(struct dm_snapshot *s, |
1508 | struct dm_snap_pending_exception *pe, chunk_t chunk) | |
1da177e4 | 1509 | { |
c6621392 | 1510 | struct dm_snap_pending_exception *pe2; |
1da177e4 | 1511 | |
2913808e MP |
1512 | pe2 = __lookup_pending_exception(s, chunk); |
1513 | if (pe2) { | |
76df1c65 | 1514 | free_pending_exception(pe); |
2913808e | 1515 | return pe2; |
1da177e4 LT |
1516 | } |
1517 | ||
76df1c65 AK |
1518 | pe->e.old_chunk = chunk; |
1519 | bio_list_init(&pe->origin_bios); | |
1520 | bio_list_init(&pe->snapshot_bios); | |
76df1c65 AK |
1521 | pe->started = 0; |
1522 | ||
493df71c | 1523 | if (s->store->type->prepare_exception(s->store, &pe->e)) { |
76df1c65 AK |
1524 | free_pending_exception(pe); |
1525 | return NULL; | |
1526 | } | |
1527 | ||
3510cb94 | 1528 | dm_insert_exception(&s->pending, &pe->e); |
76df1c65 | 1529 | |
1da177e4 LT |
1530 | return pe; |
1531 | } | |
1532 | ||
1d4989c8 | 1533 | static void remap_exception(struct dm_snapshot *s, struct dm_exception *e, |
d74f81f8 | 1534 | struct bio *bio, chunk_t chunk) |
1da177e4 | 1535 | { |
fc56f6fb | 1536 | bio->bi_bdev = s->cow->bdev; |
71fab00a JB |
1537 | bio->bi_sector = chunk_to_sector(s->store, |
1538 | dm_chunk_number(e->new_chunk) + | |
1539 | (chunk - e->old_chunk)) + | |
1540 | (bio->bi_sector & | |
1541 | s->store->chunk_mask); | |
1da177e4 LT |
1542 | } |
1543 | ||
1544 | static int snapshot_map(struct dm_target *ti, struct bio *bio, | |
1545 | union map_info *map_context) | |
1546 | { | |
1d4989c8 | 1547 | struct dm_exception *e; |
028867ac | 1548 | struct dm_snapshot *s = ti->private; |
d2a7ad29 | 1549 | int r = DM_MAPIO_REMAPPED; |
1da177e4 | 1550 | chunk_t chunk; |
028867ac | 1551 | struct dm_snap_pending_exception *pe = NULL; |
1da177e4 | 1552 | |
d87f4c14 | 1553 | if (bio->bi_rw & REQ_FLUSH) { |
fc56f6fb | 1554 | bio->bi_bdev = s->cow->bdev; |
494b3ee7 MP |
1555 | return DM_MAPIO_REMAPPED; |
1556 | } | |
1557 | ||
71fab00a | 1558 | chunk = sector_to_chunk(s->store, bio->bi_sector); |
1da177e4 LT |
1559 | |
1560 | /* Full snapshots are not usable */ | |
76df1c65 | 1561 | /* To get here the table must be live so s->active is always set. */ |
1da177e4 | 1562 | if (!s->valid) |
f6a80ea8 | 1563 | return -EIO; |
1da177e4 | 1564 | |
ba40a2aa AK |
1565 | /* FIXME: should only take write lock if we need |
1566 | * to copy an exception */ | |
1567 | down_write(&s->lock); | |
1568 | ||
1569 | if (!s->valid) { | |
1570 | r = -EIO; | |
1571 | goto out_unlock; | |
1572 | } | |
1573 | ||
1574 | /* If the block is already remapped - use that, else remap it */ | |
3510cb94 | 1575 | e = dm_lookup_exception(&s->complete, chunk); |
ba40a2aa | 1576 | if (e) { |
d74f81f8 | 1577 | remap_exception(s, e, bio, chunk); |
ba40a2aa AK |
1578 | goto out_unlock; |
1579 | } | |
1580 | ||
1da177e4 LT |
1581 | /* |
1582 | * Write to snapshot - higher level takes care of RW/RO | |
1583 | * flags so we should only get this if we are | |
1584 | * writeable. | |
1585 | */ | |
1586 | if (bio_rw(bio) == WRITE) { | |
2913808e | 1587 | pe = __lookup_pending_exception(s, chunk); |
76df1c65 | 1588 | if (!pe) { |
c6621392 MP |
1589 | up_write(&s->lock); |
1590 | pe = alloc_pending_exception(s); | |
1591 | down_write(&s->lock); | |
1592 | ||
1593 | if (!s->valid) { | |
1594 | free_pending_exception(pe); | |
1595 | r = -EIO; | |
1596 | goto out_unlock; | |
1597 | } | |
1598 | ||
3510cb94 | 1599 | e = dm_lookup_exception(&s->complete, chunk); |
35bf659b MP |
1600 | if (e) { |
1601 | free_pending_exception(pe); | |
1602 | remap_exception(s, e, bio, chunk); | |
1603 | goto out_unlock; | |
1604 | } | |
1605 | ||
c6621392 | 1606 | pe = __find_pending_exception(s, pe, chunk); |
2913808e MP |
1607 | if (!pe) { |
1608 | __invalidate_snapshot(s, -ENOMEM); | |
1609 | r = -EIO; | |
1610 | goto out_unlock; | |
1611 | } | |
1da177e4 LT |
1612 | } |
1613 | ||
d74f81f8 | 1614 | remap_exception(s, &pe->e, bio, chunk); |
76df1c65 AK |
1615 | bio_list_add(&pe->snapshot_bios, bio); |
1616 | ||
d2a7ad29 | 1617 | r = DM_MAPIO_SUBMITTED; |
ba40a2aa | 1618 | |
76df1c65 AK |
1619 | if (!pe->started) { |
1620 | /* this is protected by snap->lock */ | |
1621 | pe->started = 1; | |
ba40a2aa | 1622 | up_write(&s->lock); |
76df1c65 | 1623 | start_copy(pe); |
ba40a2aa AK |
1624 | goto out; |
1625 | } | |
cd45daff | 1626 | } else { |
ba40a2aa | 1627 | bio->bi_bdev = s->origin->bdev; |
cd45daff MP |
1628 | map_context->ptr = track_chunk(s, chunk); |
1629 | } | |
1da177e4 | 1630 | |
ba40a2aa AK |
1631 | out_unlock: |
1632 | up_write(&s->lock); | |
1633 | out: | |
1da177e4 LT |
1634 | return r; |
1635 | } | |
1636 | ||
3452c2a1 MP |
1637 | /* |
1638 | * A snapshot-merge target behaves like a combination of a snapshot | |
1639 | * target and a snapshot-origin target. It only generates new | |
1640 | * exceptions in other snapshots and not in the one that is being | |
1641 | * merged. | |
1642 | * | |
1643 | * For each chunk, if there is an existing exception, it is used to | |
1644 | * redirect I/O to the cow device. Otherwise I/O is sent to the origin, | |
1645 | * which in turn might generate exceptions in other snapshots. | |
9fe86254 MP |
1646 | * If merging is currently taking place on the chunk in question, the |
1647 | * I/O is deferred by adding it to s->bios_queued_during_merge. | |
3452c2a1 MP |
1648 | */ |
1649 | static int snapshot_merge_map(struct dm_target *ti, struct bio *bio, | |
1650 | union map_info *map_context) | |
1651 | { | |
1652 | struct dm_exception *e; | |
1653 | struct dm_snapshot *s = ti->private; | |
1654 | int r = DM_MAPIO_REMAPPED; | |
1655 | chunk_t chunk; | |
1656 | ||
d87f4c14 | 1657 | if (bio->bi_rw & REQ_FLUSH) { |
57cba5d3 | 1658 | if (!map_context->target_request_nr) |
10b8106a MS |
1659 | bio->bi_bdev = s->origin->bdev; |
1660 | else | |
1661 | bio->bi_bdev = s->cow->bdev; | |
1662 | map_context->ptr = NULL; | |
1663 | return DM_MAPIO_REMAPPED; | |
1664 | } | |
1665 | ||
3452c2a1 MP |
1666 | chunk = sector_to_chunk(s->store, bio->bi_sector); |
1667 | ||
9fe86254 | 1668 | down_write(&s->lock); |
3452c2a1 | 1669 | |
d2fdb776 MP |
1670 | /* Full merging snapshots are redirected to the origin */ |
1671 | if (!s->valid) | |
1672 | goto redirect_to_origin; | |
3452c2a1 MP |
1673 | |
1674 | /* If the block is already remapped - use that */ | |
1675 | e = dm_lookup_exception(&s->complete, chunk); | |
1676 | if (e) { | |
9fe86254 MP |
1677 | /* Queue writes overlapping with chunks being merged */ |
1678 | if (bio_rw(bio) == WRITE && | |
1679 | chunk >= s->first_merging_chunk && | |
1680 | chunk < (s->first_merging_chunk + | |
1681 | s->num_merging_chunks)) { | |
1682 | bio->bi_bdev = s->origin->bdev; | |
1683 | bio_list_add(&s->bios_queued_during_merge, bio); | |
1684 | r = DM_MAPIO_SUBMITTED; | |
1685 | goto out_unlock; | |
1686 | } | |
17aa0332 | 1687 | |
3452c2a1 | 1688 | remap_exception(s, e, bio, chunk); |
17aa0332 MP |
1689 | |
1690 | if (bio_rw(bio) == WRITE) | |
1691 | map_context->ptr = track_chunk(s, chunk); | |
3452c2a1 MP |
1692 | goto out_unlock; |
1693 | } | |
1694 | ||
d2fdb776 | 1695 | redirect_to_origin: |
3452c2a1 MP |
1696 | bio->bi_bdev = s->origin->bdev; |
1697 | ||
1698 | if (bio_rw(bio) == WRITE) { | |
9fe86254 | 1699 | up_write(&s->lock); |
3452c2a1 MP |
1700 | return do_origin(s->origin, bio); |
1701 | } | |
1702 | ||
1703 | out_unlock: | |
9fe86254 | 1704 | up_write(&s->lock); |
3452c2a1 MP |
1705 | |
1706 | return r; | |
1707 | } | |
1708 | ||
cd45daff MP |
1709 | static int snapshot_end_io(struct dm_target *ti, struct bio *bio, |
1710 | int error, union map_info *map_context) | |
1711 | { | |
1712 | struct dm_snapshot *s = ti->private; | |
1713 | struct dm_snap_tracked_chunk *c = map_context->ptr; | |
1714 | ||
1715 | if (c) | |
1716 | stop_tracking_chunk(s, c); | |
1717 | ||
1718 | return 0; | |
1719 | } | |
1720 | ||
1e03f97e MP |
1721 | static void snapshot_merge_presuspend(struct dm_target *ti) |
1722 | { | |
1723 | struct dm_snapshot *s = ti->private; | |
1724 | ||
1725 | stop_merge(s); | |
1726 | } | |
1727 | ||
c1f0c183 MS |
1728 | static int snapshot_preresume(struct dm_target *ti) |
1729 | { | |
1730 | int r = 0; | |
1731 | struct dm_snapshot *s = ti->private; | |
1732 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; | |
1733 | ||
1734 | down_read(&_origins_lock); | |
9d3b15c4 | 1735 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1736 | if (snap_src && snap_dest) { |
1737 | down_read(&snap_src->lock); | |
1738 | if (s == snap_src) { | |
1739 | DMERR("Unable to resume snapshot source until " | |
1740 | "handover completes."); | |
1741 | r = -EINVAL; | |
b83b2f29 | 1742 | } else if (!dm_suspended(snap_src->ti)) { |
c1f0c183 MS |
1743 | DMERR("Unable to perform snapshot handover until " |
1744 | "source is suspended."); | |
1745 | r = -EINVAL; | |
1746 | } | |
1747 | up_read(&snap_src->lock); | |
1748 | } | |
1749 | up_read(&_origins_lock); | |
1750 | ||
1751 | return r; | |
1752 | } | |
1753 | ||
1da177e4 LT |
1754 | static void snapshot_resume(struct dm_target *ti) |
1755 | { | |
028867ac | 1756 | struct dm_snapshot *s = ti->private; |
c1f0c183 MS |
1757 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; |
1758 | ||
1759 | down_read(&_origins_lock); | |
9d3b15c4 | 1760 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1761 | if (snap_src && snap_dest) { |
1762 | down_write(&snap_src->lock); | |
1763 | down_write_nested(&snap_dest->lock, SINGLE_DEPTH_NESTING); | |
1764 | __handover_exceptions(snap_src, snap_dest); | |
1765 | up_write(&snap_dest->lock); | |
1766 | up_write(&snap_src->lock); | |
1767 | } | |
1768 | up_read(&_origins_lock); | |
1769 | ||
1770 | /* Now we have correct chunk size, reregister */ | |
1771 | reregister_snapshot(s); | |
1da177e4 | 1772 | |
aa14edeb AK |
1773 | down_write(&s->lock); |
1774 | s->active = 1; | |
1775 | up_write(&s->lock); | |
1da177e4 LT |
1776 | } |
1777 | ||
1e03f97e MP |
1778 | static sector_t get_origin_minimum_chunksize(struct block_device *bdev) |
1779 | { | |
1780 | sector_t min_chunksize; | |
1781 | ||
1782 | down_read(&_origins_lock); | |
1783 | min_chunksize = __minimum_chunk_size(__lookup_origin(bdev)); | |
1784 | up_read(&_origins_lock); | |
1785 | ||
1786 | return min_chunksize; | |
1787 | } | |
1788 | ||
1789 | static void snapshot_merge_resume(struct dm_target *ti) | |
1790 | { | |
1791 | struct dm_snapshot *s = ti->private; | |
1792 | ||
1793 | /* | |
1794 | * Handover exceptions from existing snapshot. | |
1795 | */ | |
1796 | snapshot_resume(ti); | |
1797 | ||
1798 | /* | |
1799 | * snapshot-merge acts as an origin, so set ti->split_io | |
1800 | */ | |
1801 | ti->split_io = get_origin_minimum_chunksize(s->origin->bdev); | |
1802 | ||
1803 | start_merge(s); | |
1804 | } | |
1805 | ||
1da177e4 LT |
1806 | static int snapshot_status(struct dm_target *ti, status_type_t type, |
1807 | char *result, unsigned int maxlen) | |
1808 | { | |
2e4a31df | 1809 | unsigned sz = 0; |
028867ac | 1810 | struct dm_snapshot *snap = ti->private; |
1da177e4 LT |
1811 | |
1812 | switch (type) { | |
1813 | case STATUSTYPE_INFO: | |
94e76572 MP |
1814 | |
1815 | down_write(&snap->lock); | |
1816 | ||
1da177e4 | 1817 | if (!snap->valid) |
2e4a31df | 1818 | DMEMIT("Invalid"); |
d8ddb1cf MS |
1819 | else if (snap->merge_failed) |
1820 | DMEMIT("Merge failed"); | |
1da177e4 | 1821 | else { |
985903bb MS |
1822 | if (snap->store->type->usage) { |
1823 | sector_t total_sectors, sectors_allocated, | |
1824 | metadata_sectors; | |
1825 | snap->store->type->usage(snap->store, | |
1826 | &total_sectors, | |
1827 | §ors_allocated, | |
1828 | &metadata_sectors); | |
1829 | DMEMIT("%llu/%llu %llu", | |
1830 | (unsigned long long)sectors_allocated, | |
1831 | (unsigned long long)total_sectors, | |
1832 | (unsigned long long)metadata_sectors); | |
1da177e4 LT |
1833 | } |
1834 | else | |
2e4a31df | 1835 | DMEMIT("Unknown"); |
1da177e4 | 1836 | } |
94e76572 MP |
1837 | |
1838 | up_write(&snap->lock); | |
1839 | ||
1da177e4 LT |
1840 | break; |
1841 | ||
1842 | case STATUSTYPE_TABLE: | |
1843 | /* | |
1844 | * kdevname returns a static pointer so we need | |
1845 | * to make private copies if the output is to | |
1846 | * make sense. | |
1847 | */ | |
fc56f6fb | 1848 | DMEMIT("%s %s", snap->origin->name, snap->cow->name); |
1e302a92 JB |
1849 | snap->store->type->status(snap->store, type, result + sz, |
1850 | maxlen - sz); | |
1da177e4 LT |
1851 | break; |
1852 | } | |
1853 | ||
1854 | return 0; | |
1855 | } | |
1856 | ||
8811f46c MS |
1857 | static int snapshot_iterate_devices(struct dm_target *ti, |
1858 | iterate_devices_callout_fn fn, void *data) | |
1859 | { | |
1860 | struct dm_snapshot *snap = ti->private; | |
1e5554c8 MP |
1861 | int r; |
1862 | ||
1863 | r = fn(ti, snap->origin, 0, ti->len, data); | |
8811f46c | 1864 | |
1e5554c8 MP |
1865 | if (!r) |
1866 | r = fn(ti, snap->cow, 0, get_dev_size(snap->cow->bdev), data); | |
1867 | ||
1868 | return r; | |
8811f46c MS |
1869 | } |
1870 | ||
1871 | ||
1da177e4 LT |
1872 | /*----------------------------------------------------------------- |
1873 | * Origin methods | |
1874 | *---------------------------------------------------------------*/ | |
9eaae8ff MP |
1875 | |
1876 | /* | |
1877 | * If no exceptions need creating, DM_MAPIO_REMAPPED is returned and any | |
1878 | * supplied bio was ignored. The caller may submit it immediately. | |
1879 | * (No remapping actually occurs as the origin is always a direct linear | |
1880 | * map.) | |
1881 | * | |
1882 | * If further exceptions are required, DM_MAPIO_SUBMITTED is returned | |
1883 | * and any supplied bio is added to a list to be submitted once all | |
1884 | * the necessary exceptions exist. | |
1885 | */ | |
1886 | static int __origin_write(struct list_head *snapshots, sector_t sector, | |
1887 | struct bio *bio) | |
1da177e4 | 1888 | { |
515ad66c | 1889 | int r = DM_MAPIO_REMAPPED; |
1da177e4 | 1890 | struct dm_snapshot *snap; |
1d4989c8 | 1891 | struct dm_exception *e; |
515ad66c MP |
1892 | struct dm_snap_pending_exception *pe; |
1893 | struct dm_snap_pending_exception *pe_to_start_now = NULL; | |
1894 | struct dm_snap_pending_exception *pe_to_start_last = NULL; | |
1da177e4 LT |
1895 | chunk_t chunk; |
1896 | ||
1897 | /* Do all the snapshots on this origin */ | |
1898 | list_for_each_entry (snap, snapshots, list) { | |
3452c2a1 MP |
1899 | /* |
1900 | * Don't make new exceptions in a merging snapshot | |
1901 | * because it has effectively been deleted | |
1902 | */ | |
1903 | if (dm_target_is_snapshot_merge(snap->ti)) | |
1904 | continue; | |
1905 | ||
76df1c65 AK |
1906 | down_write(&snap->lock); |
1907 | ||
aa14edeb AK |
1908 | /* Only deal with valid and active snapshots */ |
1909 | if (!snap->valid || !snap->active) | |
76df1c65 | 1910 | goto next_snapshot; |
1da177e4 | 1911 | |
d5e404c1 | 1912 | /* Nothing to do if writing beyond end of snapshot */ |
9eaae8ff | 1913 | if (sector >= dm_table_get_size(snap->ti->table)) |
76df1c65 | 1914 | goto next_snapshot; |
1da177e4 LT |
1915 | |
1916 | /* | |
1917 | * Remember, different snapshots can have | |
1918 | * different chunk sizes. | |
1919 | */ | |
9eaae8ff | 1920 | chunk = sector_to_chunk(snap->store, sector); |
1da177e4 LT |
1921 | |
1922 | /* | |
1923 | * Check exception table to see if block | |
1924 | * is already remapped in this snapshot | |
1925 | * and trigger an exception if not. | |
1926 | */ | |
3510cb94 | 1927 | e = dm_lookup_exception(&snap->complete, chunk); |
76df1c65 AK |
1928 | if (e) |
1929 | goto next_snapshot; | |
1930 | ||
2913808e | 1931 | pe = __lookup_pending_exception(snap, chunk); |
76df1c65 | 1932 | if (!pe) { |
c6621392 MP |
1933 | up_write(&snap->lock); |
1934 | pe = alloc_pending_exception(snap); | |
1935 | down_write(&snap->lock); | |
1936 | ||
1937 | if (!snap->valid) { | |
1938 | free_pending_exception(pe); | |
1939 | goto next_snapshot; | |
1940 | } | |
1941 | ||
3510cb94 | 1942 | e = dm_lookup_exception(&snap->complete, chunk); |
35bf659b MP |
1943 | if (e) { |
1944 | free_pending_exception(pe); | |
1945 | goto next_snapshot; | |
1946 | } | |
1947 | ||
c6621392 | 1948 | pe = __find_pending_exception(snap, pe, chunk); |
2913808e MP |
1949 | if (!pe) { |
1950 | __invalidate_snapshot(snap, -ENOMEM); | |
1951 | goto next_snapshot; | |
1952 | } | |
76df1c65 AK |
1953 | } |
1954 | ||
515ad66c | 1955 | r = DM_MAPIO_SUBMITTED; |
76df1c65 | 1956 | |
515ad66c MP |
1957 | /* |
1958 | * If an origin bio was supplied, queue it to wait for the | |
1959 | * completion of this exception, and start this one last, | |
1960 | * at the end of the function. | |
1961 | */ | |
1962 | if (bio) { | |
1963 | bio_list_add(&pe->origin_bios, bio); | |
1964 | bio = NULL; | |
76df1c65 | 1965 | |
515ad66c MP |
1966 | if (!pe->started) { |
1967 | pe->started = 1; | |
1968 | pe_to_start_last = pe; | |
1969 | } | |
76df1c65 AK |
1970 | } |
1971 | ||
1972 | if (!pe->started) { | |
1973 | pe->started = 1; | |
515ad66c | 1974 | pe_to_start_now = pe; |
1da177e4 LT |
1975 | } |
1976 | ||
76df1c65 | 1977 | next_snapshot: |
1da177e4 | 1978 | up_write(&snap->lock); |
1da177e4 | 1979 | |
515ad66c MP |
1980 | if (pe_to_start_now) { |
1981 | start_copy(pe_to_start_now); | |
1982 | pe_to_start_now = NULL; | |
1983 | } | |
b4b610f6 AK |
1984 | } |
1985 | ||
1da177e4 | 1986 | /* |
515ad66c MP |
1987 | * Submit the exception against which the bio is queued last, |
1988 | * to give the other exceptions a head start. | |
1da177e4 | 1989 | */ |
515ad66c MP |
1990 | if (pe_to_start_last) |
1991 | start_copy(pe_to_start_last); | |
1da177e4 LT |
1992 | |
1993 | return r; | |
1994 | } | |
1995 | ||
1996 | /* | |
1997 | * Called on a write from the origin driver. | |
1998 | */ | |
1999 | static int do_origin(struct dm_dev *origin, struct bio *bio) | |
2000 | { | |
2001 | struct origin *o; | |
d2a7ad29 | 2002 | int r = DM_MAPIO_REMAPPED; |
1da177e4 LT |
2003 | |
2004 | down_read(&_origins_lock); | |
2005 | o = __lookup_origin(origin->bdev); | |
2006 | if (o) | |
9eaae8ff | 2007 | r = __origin_write(&o->snapshots, bio->bi_sector, bio); |
1da177e4 LT |
2008 | up_read(&_origins_lock); |
2009 | ||
2010 | return r; | |
2011 | } | |
2012 | ||
73dfd078 MP |
2013 | /* |
2014 | * Trigger exceptions in all non-merging snapshots. | |
2015 | * | |
2016 | * The chunk size of the merging snapshot may be larger than the chunk | |
2017 | * size of some other snapshot so we may need to reallocate multiple | |
2018 | * chunks in other snapshots. | |
2019 | * | |
2020 | * We scan all the overlapping exceptions in the other snapshots. | |
2021 | * Returns 1 if anything was reallocated and must be waited for, | |
2022 | * otherwise returns 0. | |
2023 | * | |
2024 | * size must be a multiple of merging_snap's chunk_size. | |
2025 | */ | |
2026 | static int origin_write_extent(struct dm_snapshot *merging_snap, | |
2027 | sector_t sector, unsigned size) | |
2028 | { | |
2029 | int must_wait = 0; | |
2030 | sector_t n; | |
2031 | struct origin *o; | |
2032 | ||
2033 | /* | |
2034 | * The origin's __minimum_chunk_size() got stored in split_io | |
2035 | * by snapshot_merge_resume(). | |
2036 | */ | |
2037 | down_read(&_origins_lock); | |
2038 | o = __lookup_origin(merging_snap->origin->bdev); | |
2039 | for (n = 0; n < size; n += merging_snap->ti->split_io) | |
2040 | if (__origin_write(&o->snapshots, sector + n, NULL) == | |
2041 | DM_MAPIO_SUBMITTED) | |
2042 | must_wait = 1; | |
2043 | up_read(&_origins_lock); | |
2044 | ||
2045 | return must_wait; | |
2046 | } | |
2047 | ||
1da177e4 LT |
2048 | /* |
2049 | * Origin: maps a linear range of a device, with hooks for snapshotting. | |
2050 | */ | |
2051 | ||
2052 | /* | |
2053 | * Construct an origin mapping: <dev_path> | |
2054 | * The context for an origin is merely a 'struct dm_dev *' | |
2055 | * pointing to the real device. | |
2056 | */ | |
2057 | static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
2058 | { | |
2059 | int r; | |
2060 | struct dm_dev *dev; | |
2061 | ||
2062 | if (argc != 1) { | |
72d94861 | 2063 | ti->error = "origin: incorrect number of arguments"; |
1da177e4 LT |
2064 | return -EINVAL; |
2065 | } | |
2066 | ||
8215d6ec | 2067 | r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev); |
1da177e4 LT |
2068 | if (r) { |
2069 | ti->error = "Cannot get target device"; | |
2070 | return r; | |
2071 | } | |
2072 | ||
2073 | ti->private = dev; | |
494b3ee7 MP |
2074 | ti->num_flush_requests = 1; |
2075 | ||
1da177e4 LT |
2076 | return 0; |
2077 | } | |
2078 | ||
2079 | static void origin_dtr(struct dm_target *ti) | |
2080 | { | |
028867ac | 2081 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2082 | dm_put_device(ti, dev); |
2083 | } | |
2084 | ||
2085 | static int origin_map(struct dm_target *ti, struct bio *bio, | |
2086 | union map_info *map_context) | |
2087 | { | |
028867ac | 2088 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2089 | bio->bi_bdev = dev->bdev; |
2090 | ||
d87f4c14 | 2091 | if (bio->bi_rw & REQ_FLUSH) |
494b3ee7 MP |
2092 | return DM_MAPIO_REMAPPED; |
2093 | ||
1da177e4 | 2094 | /* Only tell snapshots if this is a write */ |
d2a7ad29 | 2095 | return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; |
1da177e4 LT |
2096 | } |
2097 | ||
1da177e4 LT |
2098 | /* |
2099 | * Set the target "split_io" field to the minimum of all the snapshots' | |
2100 | * chunk sizes. | |
2101 | */ | |
2102 | static void origin_resume(struct dm_target *ti) | |
2103 | { | |
028867ac | 2104 | struct dm_dev *dev = ti->private; |
1da177e4 | 2105 | |
1e03f97e | 2106 | ti->split_io = get_origin_minimum_chunksize(dev->bdev); |
1da177e4 LT |
2107 | } |
2108 | ||
2109 | static int origin_status(struct dm_target *ti, status_type_t type, char *result, | |
2110 | unsigned int maxlen) | |
2111 | { | |
028867ac | 2112 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2113 | |
2114 | switch (type) { | |
2115 | case STATUSTYPE_INFO: | |
2116 | result[0] = '\0'; | |
2117 | break; | |
2118 | ||
2119 | case STATUSTYPE_TABLE: | |
2120 | snprintf(result, maxlen, "%s", dev->name); | |
2121 | break; | |
2122 | } | |
2123 | ||
2124 | return 0; | |
2125 | } | |
2126 | ||
b1d55528 MP |
2127 | static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
2128 | struct bio_vec *biovec, int max_size) | |
2129 | { | |
2130 | struct dm_dev *dev = ti->private; | |
2131 | struct request_queue *q = bdev_get_queue(dev->bdev); | |
2132 | ||
2133 | if (!q->merge_bvec_fn) | |
2134 | return max_size; | |
2135 | ||
2136 | bvm->bi_bdev = dev->bdev; | |
2137 | bvm->bi_sector = bvm->bi_sector; | |
2138 | ||
2139 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
2140 | } | |
2141 | ||
8811f46c MS |
2142 | static int origin_iterate_devices(struct dm_target *ti, |
2143 | iterate_devices_callout_fn fn, void *data) | |
2144 | { | |
2145 | struct dm_dev *dev = ti->private; | |
2146 | ||
2147 | return fn(ti, dev, 0, ti->len, data); | |
2148 | } | |
2149 | ||
1da177e4 LT |
2150 | static struct target_type origin_target = { |
2151 | .name = "snapshot-origin", | |
b83b2f29 | 2152 | .version = {1, 7, 1}, |
1da177e4 LT |
2153 | .module = THIS_MODULE, |
2154 | .ctr = origin_ctr, | |
2155 | .dtr = origin_dtr, | |
2156 | .map = origin_map, | |
2157 | .resume = origin_resume, | |
2158 | .status = origin_status, | |
b1d55528 | 2159 | .merge = origin_merge, |
8811f46c | 2160 | .iterate_devices = origin_iterate_devices, |
1da177e4 LT |
2161 | }; |
2162 | ||
2163 | static struct target_type snapshot_target = { | |
2164 | .name = "snapshot", | |
b83b2f29 | 2165 | .version = {1, 10, 0}, |
1da177e4 LT |
2166 | .module = THIS_MODULE, |
2167 | .ctr = snapshot_ctr, | |
2168 | .dtr = snapshot_dtr, | |
2169 | .map = snapshot_map, | |
cd45daff | 2170 | .end_io = snapshot_end_io, |
c1f0c183 | 2171 | .preresume = snapshot_preresume, |
1da177e4 LT |
2172 | .resume = snapshot_resume, |
2173 | .status = snapshot_status, | |
8811f46c | 2174 | .iterate_devices = snapshot_iterate_devices, |
1da177e4 LT |
2175 | }; |
2176 | ||
d698aa45 MP |
2177 | static struct target_type merge_target = { |
2178 | .name = dm_snapshot_merge_target_name, | |
b83b2f29 | 2179 | .version = {1, 1, 0}, |
d698aa45 MP |
2180 | .module = THIS_MODULE, |
2181 | .ctr = snapshot_ctr, | |
2182 | .dtr = snapshot_dtr, | |
3452c2a1 | 2183 | .map = snapshot_merge_map, |
d698aa45 | 2184 | .end_io = snapshot_end_io, |
1e03f97e | 2185 | .presuspend = snapshot_merge_presuspend, |
d698aa45 | 2186 | .preresume = snapshot_preresume, |
1e03f97e | 2187 | .resume = snapshot_merge_resume, |
d698aa45 MP |
2188 | .status = snapshot_status, |
2189 | .iterate_devices = snapshot_iterate_devices, | |
2190 | }; | |
2191 | ||
1da177e4 LT |
2192 | static int __init dm_snapshot_init(void) |
2193 | { | |
2194 | int r; | |
2195 | ||
4db6bfe0 AK |
2196 | r = dm_exception_store_init(); |
2197 | if (r) { | |
2198 | DMERR("Failed to initialize exception stores"); | |
2199 | return r; | |
2200 | } | |
2201 | ||
1da177e4 | 2202 | r = dm_register_target(&snapshot_target); |
d698aa45 | 2203 | if (r < 0) { |
1da177e4 | 2204 | DMERR("snapshot target register failed %d", r); |
034a186d | 2205 | goto bad_register_snapshot_target; |
1da177e4 LT |
2206 | } |
2207 | ||
2208 | r = dm_register_target(&origin_target); | |
2209 | if (r < 0) { | |
72d94861 | 2210 | DMERR("Origin target register failed %d", r); |
d698aa45 MP |
2211 | goto bad_register_origin_target; |
2212 | } | |
2213 | ||
2214 | r = dm_register_target(&merge_target); | |
2215 | if (r < 0) { | |
2216 | DMERR("Merge target register failed %d", r); | |
2217 | goto bad_register_merge_target; | |
1da177e4 LT |
2218 | } |
2219 | ||
2220 | r = init_origin_hash(); | |
2221 | if (r) { | |
2222 | DMERR("init_origin_hash failed."); | |
d698aa45 | 2223 | goto bad_origin_hash; |
1da177e4 LT |
2224 | } |
2225 | ||
1d4989c8 | 2226 | exception_cache = KMEM_CACHE(dm_exception, 0); |
1da177e4 LT |
2227 | if (!exception_cache) { |
2228 | DMERR("Couldn't create exception cache."); | |
2229 | r = -ENOMEM; | |
d698aa45 | 2230 | goto bad_exception_cache; |
1da177e4 LT |
2231 | } |
2232 | ||
028867ac | 2233 | pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0); |
1da177e4 LT |
2234 | if (!pending_cache) { |
2235 | DMERR("Couldn't create pending cache."); | |
2236 | r = -ENOMEM; | |
d698aa45 | 2237 | goto bad_pending_cache; |
1da177e4 LT |
2238 | } |
2239 | ||
cd45daff MP |
2240 | tracked_chunk_cache = KMEM_CACHE(dm_snap_tracked_chunk, 0); |
2241 | if (!tracked_chunk_cache) { | |
2242 | DMERR("Couldn't create cache to track chunks in use."); | |
2243 | r = -ENOMEM; | |
d698aa45 | 2244 | goto bad_tracked_chunk_cache; |
cd45daff MP |
2245 | } |
2246 | ||
1da177e4 LT |
2247 | return 0; |
2248 | ||
d698aa45 | 2249 | bad_tracked_chunk_cache: |
1da177e4 | 2250 | kmem_cache_destroy(pending_cache); |
d698aa45 | 2251 | bad_pending_cache: |
1da177e4 | 2252 | kmem_cache_destroy(exception_cache); |
d698aa45 | 2253 | bad_exception_cache: |
1da177e4 | 2254 | exit_origin_hash(); |
d698aa45 MP |
2255 | bad_origin_hash: |
2256 | dm_unregister_target(&merge_target); | |
2257 | bad_register_merge_target: | |
1da177e4 | 2258 | dm_unregister_target(&origin_target); |
d698aa45 | 2259 | bad_register_origin_target: |
1da177e4 | 2260 | dm_unregister_target(&snapshot_target); |
034a186d JB |
2261 | bad_register_snapshot_target: |
2262 | dm_exception_store_exit(); | |
d698aa45 | 2263 | |
1da177e4 LT |
2264 | return r; |
2265 | } | |
2266 | ||
2267 | static void __exit dm_snapshot_exit(void) | |
2268 | { | |
10d3bd09 MP |
2269 | dm_unregister_target(&snapshot_target); |
2270 | dm_unregister_target(&origin_target); | |
d698aa45 | 2271 | dm_unregister_target(&merge_target); |
1da177e4 LT |
2272 | |
2273 | exit_origin_hash(); | |
1da177e4 LT |
2274 | kmem_cache_destroy(pending_cache); |
2275 | kmem_cache_destroy(exception_cache); | |
cd45daff | 2276 | kmem_cache_destroy(tracked_chunk_cache); |
4db6bfe0 AK |
2277 | |
2278 | dm_exception_store_exit(); | |
1da177e4 LT |
2279 | } |
2280 | ||
2281 | /* Module hooks */ | |
2282 | module_init(dm_snapshot_init); | |
2283 | module_exit(dm_snapshot_exit); | |
2284 | ||
2285 | MODULE_DESCRIPTION(DM_NAME " snapshot target"); | |
2286 | MODULE_AUTHOR("Joe Thornber"); | |
2287 | MODULE_LICENSE("GPL"); |