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; | |
a6e50b40 MP |
173 | |
174 | /* | |
175 | * For writing a complete chunk, bypassing the copy. | |
176 | */ | |
177 | struct bio *full_bio; | |
178 | bio_end_io_t *full_bio_end_io; | |
179 | void *full_bio_private; | |
1da177e4 LT |
180 | }; |
181 | ||
182 | /* | |
183 | * Hash table mapping origin volumes to lists of snapshots and | |
184 | * a lock to protect it | |
185 | */ | |
e18b890b CL |
186 | static struct kmem_cache *exception_cache; |
187 | static struct kmem_cache *pending_cache; | |
1da177e4 | 188 | |
cd45daff MP |
189 | struct dm_snap_tracked_chunk { |
190 | struct hlist_node node; | |
191 | chunk_t chunk; | |
192 | }; | |
193 | ||
194 | static struct kmem_cache *tracked_chunk_cache; | |
195 | ||
196 | static struct dm_snap_tracked_chunk *track_chunk(struct dm_snapshot *s, | |
197 | chunk_t chunk) | |
198 | { | |
199 | struct dm_snap_tracked_chunk *c = mempool_alloc(s->tracked_chunk_pool, | |
200 | GFP_NOIO); | |
cd45daff MP |
201 | |
202 | c->chunk = chunk; | |
203 | ||
9aa0c0e6 | 204 | spin_lock_irq(&s->tracked_chunk_lock); |
cd45daff MP |
205 | hlist_add_head(&c->node, |
206 | &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)]); | |
9aa0c0e6 | 207 | spin_unlock_irq(&s->tracked_chunk_lock); |
cd45daff MP |
208 | |
209 | return c; | |
210 | } | |
211 | ||
212 | static void stop_tracking_chunk(struct dm_snapshot *s, | |
213 | struct dm_snap_tracked_chunk *c) | |
214 | { | |
215 | unsigned long flags; | |
216 | ||
217 | spin_lock_irqsave(&s->tracked_chunk_lock, flags); | |
218 | hlist_del(&c->node); | |
219 | spin_unlock_irqrestore(&s->tracked_chunk_lock, flags); | |
220 | ||
221 | mempool_free(c, s->tracked_chunk_pool); | |
222 | } | |
223 | ||
a8d41b59 MP |
224 | static int __chunk_is_tracked(struct dm_snapshot *s, chunk_t chunk) |
225 | { | |
226 | struct dm_snap_tracked_chunk *c; | |
227 | struct hlist_node *hn; | |
228 | int found = 0; | |
229 | ||
230 | spin_lock_irq(&s->tracked_chunk_lock); | |
231 | ||
232 | hlist_for_each_entry(c, hn, | |
233 | &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)], node) { | |
234 | if (c->chunk == chunk) { | |
235 | found = 1; | |
236 | break; | |
237 | } | |
238 | } | |
239 | ||
240 | spin_unlock_irq(&s->tracked_chunk_lock); | |
241 | ||
242 | return found; | |
243 | } | |
244 | ||
615d1eb9 MS |
245 | /* |
246 | * This conflicting I/O is extremely improbable in the caller, | |
247 | * so msleep(1) is sufficient and there is no need for a wait queue. | |
248 | */ | |
249 | static void __check_for_conflicting_io(struct dm_snapshot *s, chunk_t chunk) | |
250 | { | |
251 | while (__chunk_is_tracked(s, chunk)) | |
252 | msleep(1); | |
253 | } | |
254 | ||
1da177e4 LT |
255 | /* |
256 | * One of these per registered origin, held in the snapshot_origins hash | |
257 | */ | |
258 | struct origin { | |
259 | /* The origin device */ | |
260 | struct block_device *bdev; | |
261 | ||
262 | struct list_head hash_list; | |
263 | ||
264 | /* List of snapshots for this origin */ | |
265 | struct list_head snapshots; | |
266 | }; | |
267 | ||
268 | /* | |
269 | * Size of the hash table for origin volumes. If we make this | |
270 | * the size of the minors list then it should be nearly perfect | |
271 | */ | |
272 | #define ORIGIN_HASH_SIZE 256 | |
273 | #define ORIGIN_MASK 0xFF | |
274 | static struct list_head *_origins; | |
275 | static struct rw_semaphore _origins_lock; | |
276 | ||
73dfd078 MP |
277 | static DECLARE_WAIT_QUEUE_HEAD(_pending_exceptions_done); |
278 | static DEFINE_SPINLOCK(_pending_exceptions_done_spinlock); | |
279 | static uint64_t _pending_exceptions_done_count; | |
280 | ||
1da177e4 LT |
281 | static int init_origin_hash(void) |
282 | { | |
283 | int i; | |
284 | ||
285 | _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), | |
286 | GFP_KERNEL); | |
287 | if (!_origins) { | |
72d94861 | 288 | DMERR("unable to allocate memory"); |
1da177e4 LT |
289 | return -ENOMEM; |
290 | } | |
291 | ||
292 | for (i = 0; i < ORIGIN_HASH_SIZE; i++) | |
293 | INIT_LIST_HEAD(_origins + i); | |
294 | init_rwsem(&_origins_lock); | |
295 | ||
296 | return 0; | |
297 | } | |
298 | ||
299 | static void exit_origin_hash(void) | |
300 | { | |
301 | kfree(_origins); | |
302 | } | |
303 | ||
028867ac | 304 | static unsigned origin_hash(struct block_device *bdev) |
1da177e4 LT |
305 | { |
306 | return bdev->bd_dev & ORIGIN_MASK; | |
307 | } | |
308 | ||
309 | static struct origin *__lookup_origin(struct block_device *origin) | |
310 | { | |
311 | struct list_head *ol; | |
312 | struct origin *o; | |
313 | ||
314 | ol = &_origins[origin_hash(origin)]; | |
315 | list_for_each_entry (o, ol, hash_list) | |
316 | if (bdev_equal(o->bdev, origin)) | |
317 | return o; | |
318 | ||
319 | return NULL; | |
320 | } | |
321 | ||
322 | static void __insert_origin(struct origin *o) | |
323 | { | |
324 | struct list_head *sl = &_origins[origin_hash(o->bdev)]; | |
325 | list_add_tail(&o->hash_list, sl); | |
326 | } | |
327 | ||
c1f0c183 MS |
328 | /* |
329 | * _origins_lock must be held when calling this function. | |
330 | * Returns number of snapshots registered using the supplied cow device, plus: | |
331 | * snap_src - a snapshot suitable for use as a source of exception handover | |
332 | * snap_dest - a snapshot capable of receiving exception handover. | |
9d3b15c4 MP |
333 | * snap_merge - an existing snapshot-merge target linked to the same origin. |
334 | * There can be at most one snapshot-merge target. The parameter is optional. | |
c1f0c183 | 335 | * |
9d3b15c4 | 336 | * Possible return values and states of snap_src and snap_dest. |
c1f0c183 MS |
337 | * 0: NULL, NULL - first new snapshot |
338 | * 1: snap_src, NULL - normal snapshot | |
339 | * 2: snap_src, snap_dest - waiting for handover | |
340 | * 2: snap_src, NULL - handed over, waiting for old to be deleted | |
341 | * 1: NULL, snap_dest - source got destroyed without handover | |
342 | */ | |
343 | static int __find_snapshots_sharing_cow(struct dm_snapshot *snap, | |
344 | struct dm_snapshot **snap_src, | |
9d3b15c4 MP |
345 | struct dm_snapshot **snap_dest, |
346 | struct dm_snapshot **snap_merge) | |
c1f0c183 MS |
347 | { |
348 | struct dm_snapshot *s; | |
349 | struct origin *o; | |
350 | int count = 0; | |
351 | int active; | |
352 | ||
353 | o = __lookup_origin(snap->origin->bdev); | |
354 | if (!o) | |
355 | goto out; | |
356 | ||
357 | list_for_each_entry(s, &o->snapshots, list) { | |
9d3b15c4 MP |
358 | if (dm_target_is_snapshot_merge(s->ti) && snap_merge) |
359 | *snap_merge = s; | |
c1f0c183 MS |
360 | if (!bdev_equal(s->cow->bdev, snap->cow->bdev)) |
361 | continue; | |
362 | ||
363 | down_read(&s->lock); | |
364 | active = s->active; | |
365 | up_read(&s->lock); | |
366 | ||
367 | if (active) { | |
368 | if (snap_src) | |
369 | *snap_src = s; | |
370 | } else if (snap_dest) | |
371 | *snap_dest = s; | |
372 | ||
373 | count++; | |
374 | } | |
375 | ||
376 | out: | |
377 | return count; | |
378 | } | |
379 | ||
380 | /* | |
381 | * On success, returns 1 if this snapshot is a handover destination, | |
382 | * otherwise returns 0. | |
383 | */ | |
384 | static int __validate_exception_handover(struct dm_snapshot *snap) | |
385 | { | |
386 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; | |
9d3b15c4 | 387 | struct dm_snapshot *snap_merge = NULL; |
c1f0c183 MS |
388 | |
389 | /* Does snapshot need exceptions handed over to it? */ | |
9d3b15c4 MP |
390 | if ((__find_snapshots_sharing_cow(snap, &snap_src, &snap_dest, |
391 | &snap_merge) == 2) || | |
c1f0c183 MS |
392 | snap_dest) { |
393 | snap->ti->error = "Snapshot cow pairing for exception " | |
394 | "table handover failed"; | |
395 | return -EINVAL; | |
396 | } | |
397 | ||
398 | /* | |
399 | * If no snap_src was found, snap cannot become a handover | |
400 | * destination. | |
401 | */ | |
402 | if (!snap_src) | |
403 | return 0; | |
404 | ||
9d3b15c4 MP |
405 | /* |
406 | * Non-snapshot-merge handover? | |
407 | */ | |
408 | if (!dm_target_is_snapshot_merge(snap->ti)) | |
409 | return 1; | |
410 | ||
411 | /* | |
412 | * Do not allow more than one merging snapshot. | |
413 | */ | |
414 | if (snap_merge) { | |
415 | snap->ti->error = "A snapshot is already merging."; | |
416 | return -EINVAL; | |
417 | } | |
418 | ||
1e03f97e MP |
419 | if (!snap_src->store->type->prepare_merge || |
420 | !snap_src->store->type->commit_merge) { | |
421 | snap->ti->error = "Snapshot exception store does not " | |
422 | "support snapshot-merge."; | |
423 | return -EINVAL; | |
424 | } | |
425 | ||
c1f0c183 MS |
426 | return 1; |
427 | } | |
428 | ||
429 | static void __insert_snapshot(struct origin *o, struct dm_snapshot *s) | |
430 | { | |
431 | struct dm_snapshot *l; | |
432 | ||
433 | /* Sort the list according to chunk size, largest-first smallest-last */ | |
434 | list_for_each_entry(l, &o->snapshots, list) | |
435 | if (l->store->chunk_size < s->store->chunk_size) | |
436 | break; | |
437 | list_add_tail(&s->list, &l->list); | |
438 | } | |
439 | ||
1da177e4 LT |
440 | /* |
441 | * Make a note of the snapshot and its origin so we can look it | |
442 | * up when the origin has a write on it. | |
c1f0c183 MS |
443 | * |
444 | * Also validate snapshot exception store handovers. | |
445 | * On success, returns 1 if this registration is a handover destination, | |
446 | * otherwise returns 0. | |
1da177e4 LT |
447 | */ |
448 | static int register_snapshot(struct dm_snapshot *snap) | |
449 | { | |
c1f0c183 | 450 | struct origin *o, *new_o = NULL; |
1da177e4 | 451 | struct block_device *bdev = snap->origin->bdev; |
c1f0c183 | 452 | int r = 0; |
1da177e4 | 453 | |
60c856c8 MP |
454 | new_o = kmalloc(sizeof(*new_o), GFP_KERNEL); |
455 | if (!new_o) | |
456 | return -ENOMEM; | |
457 | ||
1da177e4 | 458 | down_write(&_origins_lock); |
1da177e4 | 459 | |
c1f0c183 MS |
460 | r = __validate_exception_handover(snap); |
461 | if (r < 0) { | |
462 | kfree(new_o); | |
463 | goto out; | |
464 | } | |
465 | ||
466 | o = __lookup_origin(bdev); | |
60c856c8 MP |
467 | if (o) |
468 | kfree(new_o); | |
469 | else { | |
1da177e4 | 470 | /* New origin */ |
60c856c8 | 471 | o = new_o; |
1da177e4 LT |
472 | |
473 | /* Initialise the struct */ | |
474 | INIT_LIST_HEAD(&o->snapshots); | |
475 | o->bdev = bdev; | |
476 | ||
477 | __insert_origin(o); | |
478 | } | |
479 | ||
c1f0c183 MS |
480 | __insert_snapshot(o, snap); |
481 | ||
482 | out: | |
483 | up_write(&_origins_lock); | |
484 | ||
485 | return r; | |
486 | } | |
487 | ||
488 | /* | |
489 | * Move snapshot to correct place in list according to chunk size. | |
490 | */ | |
491 | static void reregister_snapshot(struct dm_snapshot *s) | |
492 | { | |
493 | struct block_device *bdev = s->origin->bdev; | |
494 | ||
495 | down_write(&_origins_lock); | |
496 | ||
497 | list_del(&s->list); | |
498 | __insert_snapshot(__lookup_origin(bdev), s); | |
1da177e4 LT |
499 | |
500 | up_write(&_origins_lock); | |
1da177e4 LT |
501 | } |
502 | ||
503 | static void unregister_snapshot(struct dm_snapshot *s) | |
504 | { | |
505 | struct origin *o; | |
506 | ||
507 | down_write(&_origins_lock); | |
508 | o = __lookup_origin(s->origin->bdev); | |
509 | ||
510 | list_del(&s->list); | |
c1f0c183 | 511 | if (o && list_empty(&o->snapshots)) { |
1da177e4 LT |
512 | list_del(&o->hash_list); |
513 | kfree(o); | |
514 | } | |
515 | ||
516 | up_write(&_origins_lock); | |
517 | } | |
518 | ||
519 | /* | |
520 | * Implementation of the exception hash tables. | |
d74f81f8 MB |
521 | * The lowest hash_shift bits of the chunk number are ignored, allowing |
522 | * some consecutive chunks to be grouped together. | |
1da177e4 | 523 | */ |
3510cb94 JB |
524 | static int dm_exception_table_init(struct dm_exception_table *et, |
525 | uint32_t size, unsigned hash_shift) | |
1da177e4 LT |
526 | { |
527 | unsigned int i; | |
528 | ||
d74f81f8 | 529 | et->hash_shift = hash_shift; |
1da177e4 LT |
530 | et->hash_mask = size - 1; |
531 | et->table = dm_vcalloc(size, sizeof(struct list_head)); | |
532 | if (!et->table) | |
533 | return -ENOMEM; | |
534 | ||
535 | for (i = 0; i < size; i++) | |
536 | INIT_LIST_HEAD(et->table + i); | |
537 | ||
538 | return 0; | |
539 | } | |
540 | ||
3510cb94 JB |
541 | static void dm_exception_table_exit(struct dm_exception_table *et, |
542 | struct kmem_cache *mem) | |
1da177e4 LT |
543 | { |
544 | struct list_head *slot; | |
1d4989c8 | 545 | struct dm_exception *ex, *next; |
1da177e4 LT |
546 | int i, size; |
547 | ||
548 | size = et->hash_mask + 1; | |
549 | for (i = 0; i < size; i++) { | |
550 | slot = et->table + i; | |
551 | ||
552 | list_for_each_entry_safe (ex, next, slot, hash_list) | |
553 | kmem_cache_free(mem, ex); | |
554 | } | |
555 | ||
556 | vfree(et->table); | |
557 | } | |
558 | ||
191437a5 | 559 | static uint32_t exception_hash(struct dm_exception_table *et, chunk_t chunk) |
1da177e4 | 560 | { |
d74f81f8 | 561 | return (chunk >> et->hash_shift) & et->hash_mask; |
1da177e4 LT |
562 | } |
563 | ||
3510cb94 | 564 | static void dm_remove_exception(struct dm_exception *e) |
1da177e4 LT |
565 | { |
566 | list_del(&e->hash_list); | |
567 | } | |
568 | ||
569 | /* | |
570 | * Return the exception data for a sector, or NULL if not | |
571 | * remapped. | |
572 | */ | |
3510cb94 JB |
573 | static struct dm_exception *dm_lookup_exception(struct dm_exception_table *et, |
574 | chunk_t chunk) | |
1da177e4 LT |
575 | { |
576 | struct list_head *slot; | |
1d4989c8 | 577 | struct dm_exception *e; |
1da177e4 LT |
578 | |
579 | slot = &et->table[exception_hash(et, chunk)]; | |
580 | list_for_each_entry (e, slot, hash_list) | |
d74f81f8 MB |
581 | if (chunk >= e->old_chunk && |
582 | chunk <= e->old_chunk + dm_consecutive_chunk_count(e)) | |
1da177e4 LT |
583 | return e; |
584 | ||
585 | return NULL; | |
586 | } | |
587 | ||
3510cb94 | 588 | static struct dm_exception *alloc_completed_exception(void) |
1da177e4 | 589 | { |
1d4989c8 | 590 | struct dm_exception *e; |
1da177e4 LT |
591 | |
592 | e = kmem_cache_alloc(exception_cache, GFP_NOIO); | |
593 | if (!e) | |
594 | e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); | |
595 | ||
596 | return e; | |
597 | } | |
598 | ||
3510cb94 | 599 | static void free_completed_exception(struct dm_exception *e) |
1da177e4 LT |
600 | { |
601 | kmem_cache_free(exception_cache, e); | |
602 | } | |
603 | ||
92e86812 | 604 | static struct dm_snap_pending_exception *alloc_pending_exception(struct dm_snapshot *s) |
1da177e4 | 605 | { |
92e86812 MP |
606 | struct dm_snap_pending_exception *pe = mempool_alloc(s->pending_pool, |
607 | GFP_NOIO); | |
608 | ||
879129d2 | 609 | atomic_inc(&s->pending_exceptions_count); |
92e86812 MP |
610 | pe->snap = s; |
611 | ||
612 | return pe; | |
1da177e4 LT |
613 | } |
614 | ||
028867ac | 615 | static void free_pending_exception(struct dm_snap_pending_exception *pe) |
1da177e4 | 616 | { |
879129d2 MP |
617 | struct dm_snapshot *s = pe->snap; |
618 | ||
619 | mempool_free(pe, s->pending_pool); | |
620 | smp_mb__before_atomic_dec(); | |
621 | atomic_dec(&s->pending_exceptions_count); | |
1da177e4 LT |
622 | } |
623 | ||
3510cb94 JB |
624 | static void dm_insert_exception(struct dm_exception_table *eh, |
625 | struct dm_exception *new_e) | |
d74f81f8 | 626 | { |
d74f81f8 | 627 | struct list_head *l; |
1d4989c8 | 628 | struct dm_exception *e = NULL; |
d74f81f8 MB |
629 | |
630 | l = &eh->table[exception_hash(eh, new_e->old_chunk)]; | |
631 | ||
632 | /* Add immediately if this table doesn't support consecutive chunks */ | |
633 | if (!eh->hash_shift) | |
634 | goto out; | |
635 | ||
636 | /* List is ordered by old_chunk */ | |
637 | list_for_each_entry_reverse(e, l, hash_list) { | |
638 | /* Insert after an existing chunk? */ | |
639 | if (new_e->old_chunk == (e->old_chunk + | |
640 | dm_consecutive_chunk_count(e) + 1) && | |
641 | new_e->new_chunk == (dm_chunk_number(e->new_chunk) + | |
642 | dm_consecutive_chunk_count(e) + 1)) { | |
643 | dm_consecutive_chunk_count_inc(e); | |
3510cb94 | 644 | free_completed_exception(new_e); |
d74f81f8 MB |
645 | return; |
646 | } | |
647 | ||
648 | /* Insert before an existing chunk? */ | |
649 | if (new_e->old_chunk == (e->old_chunk - 1) && | |
650 | new_e->new_chunk == (dm_chunk_number(e->new_chunk) - 1)) { | |
651 | dm_consecutive_chunk_count_inc(e); | |
652 | e->old_chunk--; | |
653 | e->new_chunk--; | |
3510cb94 | 654 | free_completed_exception(new_e); |
d74f81f8 MB |
655 | return; |
656 | } | |
657 | ||
658 | if (new_e->old_chunk > e->old_chunk) | |
659 | break; | |
660 | } | |
661 | ||
662 | out: | |
663 | list_add(&new_e->hash_list, e ? &e->hash_list : l); | |
664 | } | |
665 | ||
a159c1ac JB |
666 | /* |
667 | * Callback used by the exception stores to load exceptions when | |
668 | * initialising. | |
669 | */ | |
670 | static int dm_add_exception(void *context, chunk_t old, chunk_t new) | |
1da177e4 | 671 | { |
a159c1ac | 672 | struct dm_snapshot *s = context; |
1d4989c8 | 673 | struct dm_exception *e; |
1da177e4 | 674 | |
3510cb94 | 675 | e = alloc_completed_exception(); |
1da177e4 LT |
676 | if (!e) |
677 | return -ENOMEM; | |
678 | ||
679 | e->old_chunk = old; | |
d74f81f8 MB |
680 | |
681 | /* Consecutive_count is implicitly initialised to zero */ | |
1da177e4 | 682 | e->new_chunk = new; |
d74f81f8 | 683 | |
3510cb94 | 684 | dm_insert_exception(&s->complete, e); |
d74f81f8 | 685 | |
1da177e4 LT |
686 | return 0; |
687 | } | |
688 | ||
7e201b35 MP |
689 | /* |
690 | * Return a minimum chunk size of all snapshots that have the specified origin. | |
691 | * Return zero if the origin has no snapshots. | |
692 | */ | |
542f9038 | 693 | static uint32_t __minimum_chunk_size(struct origin *o) |
7e201b35 MP |
694 | { |
695 | struct dm_snapshot *snap; | |
696 | unsigned chunk_size = 0; | |
697 | ||
698 | if (o) | |
699 | list_for_each_entry(snap, &o->snapshots, list) | |
700 | chunk_size = min_not_zero(chunk_size, | |
701 | snap->store->chunk_size); | |
702 | ||
542f9038 | 703 | return (uint32_t) chunk_size; |
7e201b35 MP |
704 | } |
705 | ||
1da177e4 LT |
706 | /* |
707 | * Hard coded magic. | |
708 | */ | |
709 | static int calc_max_buckets(void) | |
710 | { | |
711 | /* use a fixed size of 2MB */ | |
712 | unsigned long mem = 2 * 1024 * 1024; | |
713 | mem /= sizeof(struct list_head); | |
714 | ||
715 | return mem; | |
716 | } | |
717 | ||
1da177e4 LT |
718 | /* |
719 | * Allocate room for a suitable hash table. | |
720 | */ | |
fee1998e | 721 | static int init_hash_tables(struct dm_snapshot *s) |
1da177e4 LT |
722 | { |
723 | sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; | |
724 | ||
725 | /* | |
726 | * Calculate based on the size of the original volume or | |
727 | * the COW volume... | |
728 | */ | |
fc56f6fb | 729 | cow_dev_size = get_dev_size(s->cow->bdev); |
1da177e4 LT |
730 | origin_dev_size = get_dev_size(s->origin->bdev); |
731 | max_buckets = calc_max_buckets(); | |
732 | ||
fee1998e | 733 | hash_size = min(origin_dev_size, cow_dev_size) >> s->store->chunk_shift; |
1da177e4 LT |
734 | hash_size = min(hash_size, max_buckets); |
735 | ||
8e87b9b8 MP |
736 | if (hash_size < 64) |
737 | hash_size = 64; | |
8defd830 | 738 | hash_size = rounddown_pow_of_two(hash_size); |
3510cb94 JB |
739 | if (dm_exception_table_init(&s->complete, hash_size, |
740 | DM_CHUNK_CONSECUTIVE_BITS)) | |
1da177e4 LT |
741 | return -ENOMEM; |
742 | ||
743 | /* | |
744 | * Allocate hash table for in-flight exceptions | |
745 | * Make this smaller than the real hash table | |
746 | */ | |
747 | hash_size >>= 3; | |
748 | if (hash_size < 64) | |
749 | hash_size = 64; | |
750 | ||
3510cb94 JB |
751 | if (dm_exception_table_init(&s->pending, hash_size, 0)) { |
752 | dm_exception_table_exit(&s->complete, exception_cache); | |
1da177e4 LT |
753 | return -ENOMEM; |
754 | } | |
755 | ||
756 | return 0; | |
757 | } | |
758 | ||
1e03f97e MP |
759 | static void merge_shutdown(struct dm_snapshot *s) |
760 | { | |
761 | clear_bit_unlock(RUNNING_MERGE, &s->state_bits); | |
762 | smp_mb__after_clear_bit(); | |
763 | wake_up_bit(&s->state_bits, RUNNING_MERGE); | |
764 | } | |
765 | ||
9fe86254 MP |
766 | static struct bio *__release_queued_bios_after_merge(struct dm_snapshot *s) |
767 | { | |
768 | s->first_merging_chunk = 0; | |
769 | s->num_merging_chunks = 0; | |
770 | ||
771 | return bio_list_get(&s->bios_queued_during_merge); | |
772 | } | |
773 | ||
1e03f97e MP |
774 | /* |
775 | * Remove one chunk from the index of completed exceptions. | |
776 | */ | |
777 | static int __remove_single_exception_chunk(struct dm_snapshot *s, | |
778 | chunk_t old_chunk) | |
779 | { | |
780 | struct dm_exception *e; | |
781 | ||
1e03f97e MP |
782 | e = dm_lookup_exception(&s->complete, old_chunk); |
783 | if (!e) { | |
784 | DMERR("Corruption detected: exception for block %llu is " | |
785 | "on disk but not in memory", | |
786 | (unsigned long long)old_chunk); | |
787 | return -EINVAL; | |
788 | } | |
789 | ||
790 | /* | |
791 | * If this is the only chunk using this exception, remove exception. | |
792 | */ | |
793 | if (!dm_consecutive_chunk_count(e)) { | |
794 | dm_remove_exception(e); | |
795 | free_completed_exception(e); | |
796 | return 0; | |
797 | } | |
798 | ||
799 | /* | |
800 | * The chunk may be either at the beginning or the end of a | |
801 | * group of consecutive chunks - never in the middle. We are | |
802 | * removing chunks in the opposite order to that in which they | |
803 | * were added, so this should always be true. | |
804 | * Decrement the consecutive chunk counter and adjust the | |
805 | * starting point if necessary. | |
806 | */ | |
807 | if (old_chunk == e->old_chunk) { | |
808 | e->old_chunk++; | |
809 | e->new_chunk++; | |
810 | } else if (old_chunk != e->old_chunk + | |
811 | dm_consecutive_chunk_count(e)) { | |
812 | DMERR("Attempt to merge block %llu from the " | |
813 | "middle of a chunk range [%llu - %llu]", | |
814 | (unsigned long long)old_chunk, | |
815 | (unsigned long long)e->old_chunk, | |
816 | (unsigned long long) | |
817 | e->old_chunk + dm_consecutive_chunk_count(e)); | |
818 | return -EINVAL; | |
819 | } | |
820 | ||
821 | dm_consecutive_chunk_count_dec(e); | |
822 | ||
823 | return 0; | |
824 | } | |
825 | ||
9fe86254 MP |
826 | static void flush_bios(struct bio *bio); |
827 | ||
828 | static int remove_single_exception_chunk(struct dm_snapshot *s) | |
1e03f97e | 829 | { |
9fe86254 MP |
830 | struct bio *b = NULL; |
831 | int r; | |
832 | chunk_t old_chunk = s->first_merging_chunk + s->num_merging_chunks - 1; | |
1e03f97e MP |
833 | |
834 | down_write(&s->lock); | |
9fe86254 MP |
835 | |
836 | /* | |
837 | * Process chunks (and associated exceptions) in reverse order | |
838 | * so that dm_consecutive_chunk_count_dec() accounting works. | |
839 | */ | |
840 | do { | |
841 | r = __remove_single_exception_chunk(s, old_chunk); | |
842 | if (r) | |
843 | goto out; | |
844 | } while (old_chunk-- > s->first_merging_chunk); | |
845 | ||
846 | b = __release_queued_bios_after_merge(s); | |
847 | ||
848 | out: | |
1e03f97e | 849 | up_write(&s->lock); |
9fe86254 MP |
850 | if (b) |
851 | flush_bios(b); | |
1e03f97e MP |
852 | |
853 | return r; | |
854 | } | |
855 | ||
73dfd078 MP |
856 | static int origin_write_extent(struct dm_snapshot *merging_snap, |
857 | sector_t sector, unsigned chunk_size); | |
858 | ||
1e03f97e MP |
859 | static void merge_callback(int read_err, unsigned long write_err, |
860 | void *context); | |
861 | ||
73dfd078 MP |
862 | static uint64_t read_pending_exceptions_done_count(void) |
863 | { | |
864 | uint64_t pending_exceptions_done; | |
865 | ||
866 | spin_lock(&_pending_exceptions_done_spinlock); | |
867 | pending_exceptions_done = _pending_exceptions_done_count; | |
868 | spin_unlock(&_pending_exceptions_done_spinlock); | |
869 | ||
870 | return pending_exceptions_done; | |
871 | } | |
872 | ||
873 | static void increment_pending_exceptions_done_count(void) | |
874 | { | |
875 | spin_lock(&_pending_exceptions_done_spinlock); | |
876 | _pending_exceptions_done_count++; | |
877 | spin_unlock(&_pending_exceptions_done_spinlock); | |
878 | ||
879 | wake_up_all(&_pending_exceptions_done); | |
880 | } | |
881 | ||
1e03f97e MP |
882 | static void snapshot_merge_next_chunks(struct dm_snapshot *s) |
883 | { | |
8a2d5286 | 884 | int i, linear_chunks; |
1e03f97e MP |
885 | chunk_t old_chunk, new_chunk; |
886 | struct dm_io_region src, dest; | |
8a2d5286 | 887 | sector_t io_size; |
73dfd078 | 888 | uint64_t previous_count; |
1e03f97e MP |
889 | |
890 | BUG_ON(!test_bit(RUNNING_MERGE, &s->state_bits)); | |
891 | if (unlikely(test_bit(SHUTDOWN_MERGE, &s->state_bits))) | |
892 | goto shut; | |
893 | ||
894 | /* | |
895 | * valid flag never changes during merge, so no lock required. | |
896 | */ | |
897 | if (!s->valid) { | |
898 | DMERR("Snapshot is invalid: can't merge"); | |
899 | goto shut; | |
900 | } | |
901 | ||
8a2d5286 MS |
902 | linear_chunks = s->store->type->prepare_merge(s->store, &old_chunk, |
903 | &new_chunk); | |
904 | if (linear_chunks <= 0) { | |
d8ddb1cf | 905 | if (linear_chunks < 0) { |
1e03f97e MP |
906 | DMERR("Read error in exception store: " |
907 | "shutting down merge"); | |
d8ddb1cf MS |
908 | down_write(&s->lock); |
909 | s->merge_failed = 1; | |
910 | up_write(&s->lock); | |
911 | } | |
1e03f97e MP |
912 | goto shut; |
913 | } | |
914 | ||
8a2d5286 MS |
915 | /* Adjust old_chunk and new_chunk to reflect start of linear region */ |
916 | old_chunk = old_chunk + 1 - linear_chunks; | |
917 | new_chunk = new_chunk + 1 - linear_chunks; | |
918 | ||
919 | /* | |
920 | * Use one (potentially large) I/O to copy all 'linear_chunks' | |
921 | * from the exception store to the origin | |
922 | */ | |
923 | io_size = linear_chunks * s->store->chunk_size; | |
1e03f97e | 924 | |
1e03f97e MP |
925 | dest.bdev = s->origin->bdev; |
926 | dest.sector = chunk_to_sector(s->store, old_chunk); | |
8a2d5286 | 927 | dest.count = min(io_size, get_dev_size(dest.bdev) - dest.sector); |
1e03f97e MP |
928 | |
929 | src.bdev = s->cow->bdev; | |
930 | src.sector = chunk_to_sector(s->store, new_chunk); | |
931 | src.count = dest.count; | |
932 | ||
73dfd078 MP |
933 | /* |
934 | * Reallocate any exceptions needed in other snapshots then | |
935 | * wait for the pending exceptions to complete. | |
936 | * Each time any pending exception (globally on the system) | |
937 | * completes we are woken and repeat the process to find out | |
938 | * if we can proceed. While this may not seem a particularly | |
939 | * efficient algorithm, it is not expected to have any | |
940 | * significant impact on performance. | |
941 | */ | |
942 | previous_count = read_pending_exceptions_done_count(); | |
8a2d5286 | 943 | while (origin_write_extent(s, dest.sector, io_size)) { |
73dfd078 MP |
944 | wait_event(_pending_exceptions_done, |
945 | (read_pending_exceptions_done_count() != | |
946 | previous_count)); | |
947 | /* Retry after the wait, until all exceptions are done. */ | |
948 | previous_count = read_pending_exceptions_done_count(); | |
949 | } | |
950 | ||
9fe86254 MP |
951 | down_write(&s->lock); |
952 | s->first_merging_chunk = old_chunk; | |
8a2d5286 | 953 | s->num_merging_chunks = linear_chunks; |
9fe86254 MP |
954 | up_write(&s->lock); |
955 | ||
8a2d5286 MS |
956 | /* Wait until writes to all 'linear_chunks' drain */ |
957 | for (i = 0; i < linear_chunks; i++) | |
958 | __check_for_conflicting_io(s, old_chunk + i); | |
9fe86254 | 959 | |
1e03f97e MP |
960 | dm_kcopyd_copy(s->kcopyd_client, &src, 1, &dest, 0, merge_callback, s); |
961 | return; | |
962 | ||
963 | shut: | |
964 | merge_shutdown(s); | |
965 | } | |
966 | ||
9fe86254 MP |
967 | static void error_bios(struct bio *bio); |
968 | ||
1e03f97e MP |
969 | static void merge_callback(int read_err, unsigned long write_err, void *context) |
970 | { | |
971 | struct dm_snapshot *s = context; | |
9fe86254 | 972 | struct bio *b = NULL; |
1e03f97e MP |
973 | |
974 | if (read_err || write_err) { | |
975 | if (read_err) | |
976 | DMERR("Read error: shutting down merge."); | |
977 | else | |
978 | DMERR("Write error: shutting down merge."); | |
979 | goto shut; | |
980 | } | |
981 | ||
9fe86254 MP |
982 | if (s->store->type->commit_merge(s->store, |
983 | s->num_merging_chunks) < 0) { | |
1e03f97e MP |
984 | DMERR("Write error in exception store: shutting down merge"); |
985 | goto shut; | |
986 | } | |
987 | ||
9fe86254 MP |
988 | if (remove_single_exception_chunk(s) < 0) |
989 | goto shut; | |
990 | ||
1e03f97e MP |
991 | snapshot_merge_next_chunks(s); |
992 | ||
993 | return; | |
994 | ||
995 | shut: | |
9fe86254 | 996 | down_write(&s->lock); |
d8ddb1cf | 997 | s->merge_failed = 1; |
9fe86254 MP |
998 | b = __release_queued_bios_after_merge(s); |
999 | up_write(&s->lock); | |
1000 | error_bios(b); | |
1001 | ||
1e03f97e MP |
1002 | merge_shutdown(s); |
1003 | } | |
1004 | ||
1005 | static void start_merge(struct dm_snapshot *s) | |
1006 | { | |
1007 | if (!test_and_set_bit(RUNNING_MERGE, &s->state_bits)) | |
1008 | snapshot_merge_next_chunks(s); | |
1009 | } | |
1010 | ||
1011 | static int wait_schedule(void *ptr) | |
1012 | { | |
1013 | schedule(); | |
1014 | ||
1015 | return 0; | |
1016 | } | |
1017 | ||
1018 | /* | |
1019 | * Stop the merging process and wait until it finishes. | |
1020 | */ | |
1021 | static void stop_merge(struct dm_snapshot *s) | |
1022 | { | |
1023 | set_bit(SHUTDOWN_MERGE, &s->state_bits); | |
1024 | wait_on_bit(&s->state_bits, RUNNING_MERGE, wait_schedule, | |
1025 | TASK_UNINTERRUPTIBLE); | |
1026 | clear_bit(SHUTDOWN_MERGE, &s->state_bits); | |
1027 | } | |
1028 | ||
1da177e4 LT |
1029 | /* |
1030 | * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> | |
1031 | */ | |
1032 | static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
1033 | { | |
1034 | struct dm_snapshot *s; | |
cd45daff | 1035 | int i; |
1da177e4 | 1036 | int r = -EINVAL; |
fc56f6fb | 1037 | char *origin_path, *cow_path; |
10b8106a MS |
1038 | unsigned args_used, num_flush_requests = 1; |
1039 | fmode_t origin_mode = FMODE_READ; | |
1da177e4 | 1040 | |
4c7e3bf4 | 1041 | if (argc != 4) { |
72d94861 | 1042 | ti->error = "requires exactly 4 arguments"; |
1da177e4 | 1043 | r = -EINVAL; |
fc56f6fb | 1044 | goto bad; |
1da177e4 LT |
1045 | } |
1046 | ||
10b8106a MS |
1047 | if (dm_target_is_snapshot_merge(ti)) { |
1048 | num_flush_requests = 2; | |
1049 | origin_mode = FMODE_WRITE; | |
1050 | } | |
1051 | ||
fc56f6fb MS |
1052 | s = kmalloc(sizeof(*s), GFP_KERNEL); |
1053 | if (!s) { | |
a2d2b034 | 1054 | ti->error = "Cannot allocate private snapshot structure"; |
fc56f6fb MS |
1055 | r = -ENOMEM; |
1056 | goto bad; | |
1057 | } | |
1058 | ||
c2411045 MP |
1059 | origin_path = argv[0]; |
1060 | argv++; | |
1061 | argc--; | |
1062 | ||
1063 | r = dm_get_device(ti, origin_path, origin_mode, &s->origin); | |
1064 | if (r) { | |
1065 | ti->error = "Cannot get origin device"; | |
1066 | goto bad_origin; | |
1067 | } | |
1068 | ||
fc56f6fb MS |
1069 | cow_path = argv[0]; |
1070 | argv++; | |
1071 | argc--; | |
1072 | ||
024d37e9 | 1073 | r = dm_get_device(ti, cow_path, dm_table_get_mode(ti->table), &s->cow); |
fc56f6fb MS |
1074 | if (r) { |
1075 | ti->error = "Cannot get COW device"; | |
1076 | goto bad_cow; | |
1077 | } | |
1078 | ||
1079 | r = dm_exception_store_create(ti, argc, argv, s, &args_used, &s->store); | |
fee1998e JB |
1080 | if (r) { |
1081 | ti->error = "Couldn't create exception store"; | |
1da177e4 | 1082 | r = -EINVAL; |
fc56f6fb | 1083 | goto bad_store; |
1da177e4 LT |
1084 | } |
1085 | ||
fee1998e JB |
1086 | argv += args_used; |
1087 | argc -= args_used; | |
1088 | ||
fc56f6fb | 1089 | s->ti = ti; |
1da177e4 | 1090 | s->valid = 1; |
aa14edeb | 1091 | s->active = 0; |
879129d2 | 1092 | atomic_set(&s->pending_exceptions_count, 0); |
1da177e4 | 1093 | init_rwsem(&s->lock); |
c1f0c183 | 1094 | INIT_LIST_HEAD(&s->list); |
ca3a931f | 1095 | spin_lock_init(&s->pe_lock); |
1e03f97e | 1096 | s->state_bits = 0; |
d8ddb1cf | 1097 | s->merge_failed = 0; |
9fe86254 MP |
1098 | s->first_merging_chunk = 0; |
1099 | s->num_merging_chunks = 0; | |
1100 | bio_list_init(&s->bios_queued_during_merge); | |
1da177e4 LT |
1101 | |
1102 | /* Allocate hash table for COW data */ | |
fee1998e | 1103 | if (init_hash_tables(s)) { |
1da177e4 LT |
1104 | ti->error = "Unable to allocate hash table space"; |
1105 | r = -ENOMEM; | |
fee1998e | 1106 | goto bad_hash_tables; |
1da177e4 LT |
1107 | } |
1108 | ||
fa34ce73 MP |
1109 | s->kcopyd_client = dm_kcopyd_client_create(); |
1110 | if (IS_ERR(s->kcopyd_client)) { | |
1111 | r = PTR_ERR(s->kcopyd_client); | |
1da177e4 | 1112 | ti->error = "Could not create kcopyd client"; |
fee1998e | 1113 | goto bad_kcopyd; |
1da177e4 LT |
1114 | } |
1115 | ||
92e86812 MP |
1116 | s->pending_pool = mempool_create_slab_pool(MIN_IOS, pending_cache); |
1117 | if (!s->pending_pool) { | |
1118 | ti->error = "Could not allocate mempool for pending exceptions"; | |
fee1998e | 1119 | goto bad_pending_pool; |
92e86812 MP |
1120 | } |
1121 | ||
cd45daff MP |
1122 | s->tracked_chunk_pool = mempool_create_slab_pool(MIN_IOS, |
1123 | tracked_chunk_cache); | |
1124 | if (!s->tracked_chunk_pool) { | |
1125 | ti->error = "Could not allocate tracked_chunk mempool for " | |
1126 | "tracking reads"; | |
92e86812 | 1127 | goto bad_tracked_chunk_pool; |
cd45daff MP |
1128 | } |
1129 | ||
1130 | for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) | |
1131 | INIT_HLIST_HEAD(&s->tracked_chunk_hash[i]); | |
1132 | ||
1133 | spin_lock_init(&s->tracked_chunk_lock); | |
1134 | ||
c1f0c183 | 1135 | ti->private = s; |
10b8106a | 1136 | ti->num_flush_requests = num_flush_requests; |
c1f0c183 MS |
1137 | |
1138 | /* Add snapshot to the list of snapshots for this origin */ | |
1139 | /* Exceptions aren't triggered till snapshot_resume() is called */ | |
1140 | r = register_snapshot(s); | |
1141 | if (r == -ENOMEM) { | |
1142 | ti->error = "Snapshot origin struct allocation failed"; | |
1143 | goto bad_load_and_register; | |
1144 | } else if (r < 0) { | |
1145 | /* invalid handover, register_snapshot has set ti->error */ | |
1146 | goto bad_load_and_register; | |
1147 | } | |
1148 | ||
1149 | /* | |
1150 | * Metadata must only be loaded into one table at once, so skip this | |
1151 | * if metadata will be handed over during resume. | |
1152 | * Chunk size will be set during the handover - set it to zero to | |
1153 | * ensure it's ignored. | |
1154 | */ | |
1155 | if (r > 0) { | |
1156 | s->store->chunk_size = 0; | |
1157 | return 0; | |
1158 | } | |
1159 | ||
493df71c JB |
1160 | r = s->store->type->read_metadata(s->store, dm_add_exception, |
1161 | (void *)s); | |
0764147b | 1162 | if (r < 0) { |
f9cea4f7 | 1163 | ti->error = "Failed to read snapshot metadata"; |
c1f0c183 | 1164 | goto bad_read_metadata; |
0764147b MB |
1165 | } else if (r > 0) { |
1166 | s->valid = 0; | |
1167 | DMWARN("Snapshot is marked invalid."); | |
f9cea4f7 | 1168 | } |
aa14edeb | 1169 | |
3f2412dc MP |
1170 | if (!s->store->chunk_size) { |
1171 | ti->error = "Chunk size not set"; | |
c1f0c183 | 1172 | goto bad_read_metadata; |
1da177e4 | 1173 | } |
542f9038 MS |
1174 | |
1175 | r = dm_set_target_max_io_len(ti, s->store->chunk_size); | |
1176 | if (r) | |
1177 | goto bad_read_metadata; | |
1da177e4 LT |
1178 | |
1179 | return 0; | |
1180 | ||
c1f0c183 MS |
1181 | bad_read_metadata: |
1182 | unregister_snapshot(s); | |
1183 | ||
fee1998e | 1184 | bad_load_and_register: |
cd45daff MP |
1185 | mempool_destroy(s->tracked_chunk_pool); |
1186 | ||
fee1998e | 1187 | bad_tracked_chunk_pool: |
92e86812 MP |
1188 | mempool_destroy(s->pending_pool); |
1189 | ||
fee1998e | 1190 | bad_pending_pool: |
eb69aca5 | 1191 | dm_kcopyd_client_destroy(s->kcopyd_client); |
1da177e4 | 1192 | |
fee1998e | 1193 | bad_kcopyd: |
3510cb94 JB |
1194 | dm_exception_table_exit(&s->pending, pending_cache); |
1195 | dm_exception_table_exit(&s->complete, exception_cache); | |
1da177e4 | 1196 | |
fee1998e | 1197 | bad_hash_tables: |
fc56f6fb | 1198 | dm_exception_store_destroy(s->store); |
1da177e4 | 1199 | |
fc56f6fb MS |
1200 | bad_store: |
1201 | dm_put_device(ti, s->cow); | |
fee1998e | 1202 | |
fc56f6fb | 1203 | bad_cow: |
c2411045 MP |
1204 | dm_put_device(ti, s->origin); |
1205 | ||
1206 | bad_origin: | |
fc56f6fb MS |
1207 | kfree(s); |
1208 | ||
1209 | bad: | |
1da177e4 LT |
1210 | return r; |
1211 | } | |
1212 | ||
31c93a0c MB |
1213 | static void __free_exceptions(struct dm_snapshot *s) |
1214 | { | |
eb69aca5 | 1215 | dm_kcopyd_client_destroy(s->kcopyd_client); |
31c93a0c MB |
1216 | s->kcopyd_client = NULL; |
1217 | ||
3510cb94 JB |
1218 | dm_exception_table_exit(&s->pending, pending_cache); |
1219 | dm_exception_table_exit(&s->complete, exception_cache); | |
31c93a0c MB |
1220 | } |
1221 | ||
c1f0c183 MS |
1222 | static void __handover_exceptions(struct dm_snapshot *snap_src, |
1223 | struct dm_snapshot *snap_dest) | |
1224 | { | |
1225 | union { | |
1226 | struct dm_exception_table table_swap; | |
1227 | struct dm_exception_store *store_swap; | |
1228 | } u; | |
1229 | ||
1230 | /* | |
1231 | * Swap all snapshot context information between the two instances. | |
1232 | */ | |
1233 | u.table_swap = snap_dest->complete; | |
1234 | snap_dest->complete = snap_src->complete; | |
1235 | snap_src->complete = u.table_swap; | |
1236 | ||
1237 | u.store_swap = snap_dest->store; | |
1238 | snap_dest->store = snap_src->store; | |
1239 | snap_src->store = u.store_swap; | |
1240 | ||
1241 | snap_dest->store->snap = snap_dest; | |
1242 | snap_src->store->snap = snap_src; | |
1243 | ||
542f9038 | 1244 | snap_dest->ti->max_io_len = snap_dest->store->chunk_size; |
c1f0c183 MS |
1245 | snap_dest->valid = snap_src->valid; |
1246 | ||
1247 | /* | |
1248 | * Set source invalid to ensure it receives no further I/O. | |
1249 | */ | |
1250 | snap_src->valid = 0; | |
1251 | } | |
1252 | ||
1da177e4 LT |
1253 | static void snapshot_dtr(struct dm_target *ti) |
1254 | { | |
cd45daff MP |
1255 | #ifdef CONFIG_DM_DEBUG |
1256 | int i; | |
1257 | #endif | |
028867ac | 1258 | struct dm_snapshot *s = ti->private; |
c1f0c183 | 1259 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; |
1da177e4 | 1260 | |
c1f0c183 MS |
1261 | down_read(&_origins_lock); |
1262 | /* Check whether exception handover must be cancelled */ | |
9d3b15c4 | 1263 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1264 | if (snap_src && snap_dest && (s == snap_src)) { |
1265 | down_write(&snap_dest->lock); | |
1266 | snap_dest->valid = 0; | |
1267 | up_write(&snap_dest->lock); | |
1268 | DMERR("Cancelling snapshot handover."); | |
1269 | } | |
1270 | up_read(&_origins_lock); | |
1271 | ||
1e03f97e MP |
1272 | if (dm_target_is_snapshot_merge(ti)) |
1273 | stop_merge(s); | |
1274 | ||
138728dc AK |
1275 | /* Prevent further origin writes from using this snapshot. */ |
1276 | /* After this returns there can be no new kcopyd jobs. */ | |
1da177e4 LT |
1277 | unregister_snapshot(s); |
1278 | ||
879129d2 | 1279 | while (atomic_read(&s->pending_exceptions_count)) |
90fa1527 | 1280 | msleep(1); |
879129d2 MP |
1281 | /* |
1282 | * Ensure instructions in mempool_destroy aren't reordered | |
1283 | * before atomic_read. | |
1284 | */ | |
1285 | smp_mb(); | |
1286 | ||
cd45daff MP |
1287 | #ifdef CONFIG_DM_DEBUG |
1288 | for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) | |
1289 | BUG_ON(!hlist_empty(&s->tracked_chunk_hash[i])); | |
1290 | #endif | |
1291 | ||
1292 | mempool_destroy(s->tracked_chunk_pool); | |
1293 | ||
31c93a0c | 1294 | __free_exceptions(s); |
1da177e4 | 1295 | |
92e86812 MP |
1296 | mempool_destroy(s->pending_pool); |
1297 | ||
fee1998e | 1298 | dm_exception_store_destroy(s->store); |
138728dc | 1299 | |
fc56f6fb MS |
1300 | dm_put_device(ti, s->cow); |
1301 | ||
c2411045 MP |
1302 | dm_put_device(ti, s->origin); |
1303 | ||
1da177e4 LT |
1304 | kfree(s); |
1305 | } | |
1306 | ||
1307 | /* | |
1308 | * Flush a list of buffers. | |
1309 | */ | |
1310 | static void flush_bios(struct bio *bio) | |
1311 | { | |
1312 | struct bio *n; | |
1313 | ||
1314 | while (bio) { | |
1315 | n = bio->bi_next; | |
1316 | bio->bi_next = NULL; | |
1317 | generic_make_request(bio); | |
1318 | bio = n; | |
1319 | } | |
1320 | } | |
1321 | ||
515ad66c MP |
1322 | static int do_origin(struct dm_dev *origin, struct bio *bio); |
1323 | ||
1324 | /* | |
1325 | * Flush a list of buffers. | |
1326 | */ | |
1327 | static void retry_origin_bios(struct dm_snapshot *s, struct bio *bio) | |
1328 | { | |
1329 | struct bio *n; | |
1330 | int r; | |
1331 | ||
1332 | while (bio) { | |
1333 | n = bio->bi_next; | |
1334 | bio->bi_next = NULL; | |
1335 | r = do_origin(s->origin, bio); | |
1336 | if (r == DM_MAPIO_REMAPPED) | |
1337 | generic_make_request(bio); | |
1338 | bio = n; | |
1339 | } | |
1340 | } | |
1341 | ||
1da177e4 LT |
1342 | /* |
1343 | * Error a list of buffers. | |
1344 | */ | |
1345 | static void error_bios(struct bio *bio) | |
1346 | { | |
1347 | struct bio *n; | |
1348 | ||
1349 | while (bio) { | |
1350 | n = bio->bi_next; | |
1351 | bio->bi_next = NULL; | |
6712ecf8 | 1352 | bio_io_error(bio); |
1da177e4 LT |
1353 | bio = n; |
1354 | } | |
1355 | } | |
1356 | ||
695368ac | 1357 | static void __invalidate_snapshot(struct dm_snapshot *s, int err) |
76df1c65 AK |
1358 | { |
1359 | if (!s->valid) | |
1360 | return; | |
1361 | ||
1362 | if (err == -EIO) | |
1363 | DMERR("Invalidating snapshot: Error reading/writing."); | |
1364 | else if (err == -ENOMEM) | |
1365 | DMERR("Invalidating snapshot: Unable to allocate exception."); | |
1366 | ||
493df71c JB |
1367 | if (s->store->type->drop_snapshot) |
1368 | s->store->type->drop_snapshot(s->store); | |
76df1c65 AK |
1369 | |
1370 | s->valid = 0; | |
1371 | ||
fc56f6fb | 1372 | dm_table_event(s->ti->table); |
76df1c65 AK |
1373 | } |
1374 | ||
028867ac | 1375 | static void pending_complete(struct dm_snap_pending_exception *pe, int success) |
1da177e4 | 1376 | { |
1d4989c8 | 1377 | struct dm_exception *e; |
1da177e4 | 1378 | struct dm_snapshot *s = pe->snap; |
9d493fa8 AK |
1379 | struct bio *origin_bios = NULL; |
1380 | struct bio *snapshot_bios = NULL; | |
a6e50b40 | 1381 | struct bio *full_bio = NULL; |
9d493fa8 | 1382 | int error = 0; |
1da177e4 | 1383 | |
76df1c65 AK |
1384 | if (!success) { |
1385 | /* Read/write error - snapshot is unusable */ | |
1da177e4 | 1386 | down_write(&s->lock); |
695368ac | 1387 | __invalidate_snapshot(s, -EIO); |
9d493fa8 | 1388 | error = 1; |
76df1c65 AK |
1389 | goto out; |
1390 | } | |
1391 | ||
3510cb94 | 1392 | e = alloc_completed_exception(); |
76df1c65 | 1393 | if (!e) { |
1da177e4 | 1394 | down_write(&s->lock); |
695368ac | 1395 | __invalidate_snapshot(s, -ENOMEM); |
9d493fa8 | 1396 | error = 1; |
76df1c65 AK |
1397 | goto out; |
1398 | } | |
1399 | *e = pe->e; | |
1da177e4 | 1400 | |
76df1c65 AK |
1401 | down_write(&s->lock); |
1402 | if (!s->valid) { | |
3510cb94 | 1403 | free_completed_exception(e); |
9d493fa8 | 1404 | error = 1; |
76df1c65 | 1405 | goto out; |
1da177e4 LT |
1406 | } |
1407 | ||
615d1eb9 MS |
1408 | /* Check for conflicting reads */ |
1409 | __check_for_conflicting_io(s, pe->e.old_chunk); | |
a8d41b59 | 1410 | |
9d493fa8 AK |
1411 | /* |
1412 | * Add a proper exception, and remove the | |
1413 | * in-flight exception from the list. | |
1414 | */ | |
3510cb94 | 1415 | dm_insert_exception(&s->complete, e); |
76df1c65 | 1416 | |
a2d2b034 | 1417 | out: |
3510cb94 | 1418 | dm_remove_exception(&pe->e); |
9d493fa8 | 1419 | snapshot_bios = bio_list_get(&pe->snapshot_bios); |
515ad66c | 1420 | origin_bios = bio_list_get(&pe->origin_bios); |
a6e50b40 MP |
1421 | full_bio = pe->full_bio; |
1422 | if (full_bio) { | |
1423 | full_bio->bi_end_io = pe->full_bio_end_io; | |
1424 | full_bio->bi_private = pe->full_bio_private; | |
1425 | } | |
515ad66c | 1426 | free_pending_exception(pe); |
1da177e4 | 1427 | |
73dfd078 MP |
1428 | increment_pending_exceptions_done_count(); |
1429 | ||
9d493fa8 AK |
1430 | up_write(&s->lock); |
1431 | ||
1432 | /* Submit any pending write bios */ | |
a6e50b40 MP |
1433 | if (error) { |
1434 | if (full_bio) | |
1435 | bio_io_error(full_bio); | |
9d493fa8 | 1436 | error_bios(snapshot_bios); |
a6e50b40 MP |
1437 | } else { |
1438 | if (full_bio) | |
1439 | bio_endio(full_bio, 0); | |
9d493fa8 | 1440 | flush_bios(snapshot_bios); |
a6e50b40 | 1441 | } |
9d493fa8 | 1442 | |
515ad66c | 1443 | retry_origin_bios(s, origin_bios); |
1da177e4 LT |
1444 | } |
1445 | ||
1446 | static void commit_callback(void *context, int success) | |
1447 | { | |
028867ac AK |
1448 | struct dm_snap_pending_exception *pe = context; |
1449 | ||
1da177e4 LT |
1450 | pending_complete(pe, success); |
1451 | } | |
1452 | ||
1453 | /* | |
1454 | * Called when the copy I/O has finished. kcopyd actually runs | |
1455 | * this code so don't block. | |
1456 | */ | |
4cdc1d1f | 1457 | static void copy_callback(int read_err, unsigned long write_err, void *context) |
1da177e4 | 1458 | { |
028867ac | 1459 | struct dm_snap_pending_exception *pe = context; |
1da177e4 LT |
1460 | struct dm_snapshot *s = pe->snap; |
1461 | ||
1462 | if (read_err || write_err) | |
1463 | pending_complete(pe, 0); | |
1464 | ||
1465 | else | |
1466 | /* Update the metadata if we are persistent */ | |
493df71c JB |
1467 | s->store->type->commit_exception(s->store, &pe->e, |
1468 | commit_callback, pe); | |
1da177e4 LT |
1469 | } |
1470 | ||
1471 | /* | |
1472 | * Dispatches the copy operation to kcopyd. | |
1473 | */ | |
028867ac | 1474 | static void start_copy(struct dm_snap_pending_exception *pe) |
1da177e4 LT |
1475 | { |
1476 | struct dm_snapshot *s = pe->snap; | |
22a1ceb1 | 1477 | struct dm_io_region src, dest; |
1da177e4 LT |
1478 | struct block_device *bdev = s->origin->bdev; |
1479 | sector_t dev_size; | |
1480 | ||
1481 | dev_size = get_dev_size(bdev); | |
1482 | ||
1483 | src.bdev = bdev; | |
71fab00a | 1484 | src.sector = chunk_to_sector(s->store, pe->e.old_chunk); |
df96eee6 | 1485 | src.count = min((sector_t)s->store->chunk_size, dev_size - src.sector); |
1da177e4 | 1486 | |
fc56f6fb | 1487 | dest.bdev = s->cow->bdev; |
71fab00a | 1488 | dest.sector = chunk_to_sector(s->store, pe->e.new_chunk); |
1da177e4 LT |
1489 | dest.count = src.count; |
1490 | ||
1491 | /* Hand over to kcopyd */ | |
a2d2b034 | 1492 | dm_kcopyd_copy(s->kcopyd_client, &src, 1, &dest, 0, copy_callback, pe); |
1da177e4 LT |
1493 | } |
1494 | ||
a6e50b40 MP |
1495 | static void full_bio_end_io(struct bio *bio, int error) |
1496 | { | |
1497 | void *callback_data = bio->bi_private; | |
1498 | ||
1499 | dm_kcopyd_do_callback(callback_data, 0, error ? 1 : 0); | |
1500 | } | |
1501 | ||
1502 | static void start_full_bio(struct dm_snap_pending_exception *pe, | |
1503 | struct bio *bio) | |
1504 | { | |
1505 | struct dm_snapshot *s = pe->snap; | |
1506 | void *callback_data; | |
1507 | ||
1508 | pe->full_bio = bio; | |
1509 | pe->full_bio_end_io = bio->bi_end_io; | |
1510 | pe->full_bio_private = bio->bi_private; | |
1511 | ||
1512 | callback_data = dm_kcopyd_prepare_callback(s->kcopyd_client, | |
1513 | copy_callback, pe); | |
1514 | ||
1515 | bio->bi_end_io = full_bio_end_io; | |
1516 | bio->bi_private = callback_data; | |
1517 | ||
1518 | generic_make_request(bio); | |
1519 | } | |
1520 | ||
2913808e MP |
1521 | static struct dm_snap_pending_exception * |
1522 | __lookup_pending_exception(struct dm_snapshot *s, chunk_t chunk) | |
1523 | { | |
3510cb94 | 1524 | struct dm_exception *e = dm_lookup_exception(&s->pending, chunk); |
2913808e MP |
1525 | |
1526 | if (!e) | |
1527 | return NULL; | |
1528 | ||
1529 | return container_of(e, struct dm_snap_pending_exception, e); | |
1530 | } | |
1531 | ||
1da177e4 LT |
1532 | /* |
1533 | * Looks to see if this snapshot already has a pending exception | |
1534 | * for this chunk, otherwise it allocates a new one and inserts | |
1535 | * it into the pending table. | |
1536 | * | |
1537 | * NOTE: a write lock must be held on snap->lock before calling | |
1538 | * this. | |
1539 | */ | |
028867ac | 1540 | static struct dm_snap_pending_exception * |
c6621392 MP |
1541 | __find_pending_exception(struct dm_snapshot *s, |
1542 | struct dm_snap_pending_exception *pe, chunk_t chunk) | |
1da177e4 | 1543 | { |
c6621392 | 1544 | struct dm_snap_pending_exception *pe2; |
1da177e4 | 1545 | |
2913808e MP |
1546 | pe2 = __lookup_pending_exception(s, chunk); |
1547 | if (pe2) { | |
76df1c65 | 1548 | free_pending_exception(pe); |
2913808e | 1549 | return pe2; |
1da177e4 LT |
1550 | } |
1551 | ||
76df1c65 AK |
1552 | pe->e.old_chunk = chunk; |
1553 | bio_list_init(&pe->origin_bios); | |
1554 | bio_list_init(&pe->snapshot_bios); | |
76df1c65 | 1555 | pe->started = 0; |
a6e50b40 | 1556 | pe->full_bio = NULL; |
76df1c65 | 1557 | |
493df71c | 1558 | if (s->store->type->prepare_exception(s->store, &pe->e)) { |
76df1c65 AK |
1559 | free_pending_exception(pe); |
1560 | return NULL; | |
1561 | } | |
1562 | ||
3510cb94 | 1563 | dm_insert_exception(&s->pending, &pe->e); |
76df1c65 | 1564 | |
1da177e4 LT |
1565 | return pe; |
1566 | } | |
1567 | ||
1d4989c8 | 1568 | static void remap_exception(struct dm_snapshot *s, struct dm_exception *e, |
d74f81f8 | 1569 | struct bio *bio, chunk_t chunk) |
1da177e4 | 1570 | { |
fc56f6fb | 1571 | bio->bi_bdev = s->cow->bdev; |
71fab00a JB |
1572 | bio->bi_sector = chunk_to_sector(s->store, |
1573 | dm_chunk_number(e->new_chunk) + | |
1574 | (chunk - e->old_chunk)) + | |
1575 | (bio->bi_sector & | |
1576 | s->store->chunk_mask); | |
1da177e4 LT |
1577 | } |
1578 | ||
1579 | static int snapshot_map(struct dm_target *ti, struct bio *bio, | |
1580 | union map_info *map_context) | |
1581 | { | |
1d4989c8 | 1582 | struct dm_exception *e; |
028867ac | 1583 | struct dm_snapshot *s = ti->private; |
d2a7ad29 | 1584 | int r = DM_MAPIO_REMAPPED; |
1da177e4 | 1585 | chunk_t chunk; |
028867ac | 1586 | struct dm_snap_pending_exception *pe = NULL; |
1da177e4 | 1587 | |
d87f4c14 | 1588 | if (bio->bi_rw & REQ_FLUSH) { |
fc56f6fb | 1589 | bio->bi_bdev = s->cow->bdev; |
494b3ee7 MP |
1590 | return DM_MAPIO_REMAPPED; |
1591 | } | |
1592 | ||
71fab00a | 1593 | chunk = sector_to_chunk(s->store, bio->bi_sector); |
1da177e4 LT |
1594 | |
1595 | /* Full snapshots are not usable */ | |
76df1c65 | 1596 | /* To get here the table must be live so s->active is always set. */ |
1da177e4 | 1597 | if (!s->valid) |
f6a80ea8 | 1598 | return -EIO; |
1da177e4 | 1599 | |
ba40a2aa AK |
1600 | /* FIXME: should only take write lock if we need |
1601 | * to copy an exception */ | |
1602 | down_write(&s->lock); | |
1603 | ||
1604 | if (!s->valid) { | |
1605 | r = -EIO; | |
1606 | goto out_unlock; | |
1607 | } | |
1608 | ||
1609 | /* If the block is already remapped - use that, else remap it */ | |
3510cb94 | 1610 | e = dm_lookup_exception(&s->complete, chunk); |
ba40a2aa | 1611 | if (e) { |
d74f81f8 | 1612 | remap_exception(s, e, bio, chunk); |
ba40a2aa AK |
1613 | goto out_unlock; |
1614 | } | |
1615 | ||
1da177e4 LT |
1616 | /* |
1617 | * Write to snapshot - higher level takes care of RW/RO | |
1618 | * flags so we should only get this if we are | |
1619 | * writeable. | |
1620 | */ | |
1621 | if (bio_rw(bio) == WRITE) { | |
2913808e | 1622 | pe = __lookup_pending_exception(s, chunk); |
76df1c65 | 1623 | if (!pe) { |
c6621392 MP |
1624 | up_write(&s->lock); |
1625 | pe = alloc_pending_exception(s); | |
1626 | down_write(&s->lock); | |
1627 | ||
1628 | if (!s->valid) { | |
1629 | free_pending_exception(pe); | |
1630 | r = -EIO; | |
1631 | goto out_unlock; | |
1632 | } | |
1633 | ||
3510cb94 | 1634 | e = dm_lookup_exception(&s->complete, chunk); |
35bf659b MP |
1635 | if (e) { |
1636 | free_pending_exception(pe); | |
1637 | remap_exception(s, e, bio, chunk); | |
1638 | goto out_unlock; | |
1639 | } | |
1640 | ||
c6621392 | 1641 | pe = __find_pending_exception(s, pe, chunk); |
2913808e MP |
1642 | if (!pe) { |
1643 | __invalidate_snapshot(s, -ENOMEM); | |
1644 | r = -EIO; | |
1645 | goto out_unlock; | |
1646 | } | |
1da177e4 LT |
1647 | } |
1648 | ||
d74f81f8 | 1649 | remap_exception(s, &pe->e, bio, chunk); |
76df1c65 | 1650 | |
d2a7ad29 | 1651 | r = DM_MAPIO_SUBMITTED; |
ba40a2aa | 1652 | |
a6e50b40 MP |
1653 | if (!pe->started && |
1654 | bio->bi_size == (s->store->chunk_size << SECTOR_SHIFT)) { | |
1655 | pe->started = 1; | |
1656 | up_write(&s->lock); | |
1657 | start_full_bio(pe, bio); | |
1658 | goto out; | |
1659 | } | |
1660 | ||
1661 | bio_list_add(&pe->snapshot_bios, bio); | |
1662 | ||
76df1c65 AK |
1663 | if (!pe->started) { |
1664 | /* this is protected by snap->lock */ | |
1665 | pe->started = 1; | |
ba40a2aa | 1666 | up_write(&s->lock); |
76df1c65 | 1667 | start_copy(pe); |
ba40a2aa AK |
1668 | goto out; |
1669 | } | |
cd45daff | 1670 | } else { |
ba40a2aa | 1671 | bio->bi_bdev = s->origin->bdev; |
cd45daff MP |
1672 | map_context->ptr = track_chunk(s, chunk); |
1673 | } | |
1da177e4 | 1674 | |
a2d2b034 | 1675 | out_unlock: |
ba40a2aa | 1676 | up_write(&s->lock); |
a2d2b034 | 1677 | out: |
1da177e4 LT |
1678 | return r; |
1679 | } | |
1680 | ||
3452c2a1 MP |
1681 | /* |
1682 | * A snapshot-merge target behaves like a combination of a snapshot | |
1683 | * target and a snapshot-origin target. It only generates new | |
1684 | * exceptions in other snapshots and not in the one that is being | |
1685 | * merged. | |
1686 | * | |
1687 | * For each chunk, if there is an existing exception, it is used to | |
1688 | * redirect I/O to the cow device. Otherwise I/O is sent to the origin, | |
1689 | * which in turn might generate exceptions in other snapshots. | |
9fe86254 MP |
1690 | * If merging is currently taking place on the chunk in question, the |
1691 | * I/O is deferred by adding it to s->bios_queued_during_merge. | |
3452c2a1 MP |
1692 | */ |
1693 | static int snapshot_merge_map(struct dm_target *ti, struct bio *bio, | |
1694 | union map_info *map_context) | |
1695 | { | |
1696 | struct dm_exception *e; | |
1697 | struct dm_snapshot *s = ti->private; | |
1698 | int r = DM_MAPIO_REMAPPED; | |
1699 | chunk_t chunk; | |
1700 | ||
d87f4c14 | 1701 | if (bio->bi_rw & REQ_FLUSH) { |
57cba5d3 | 1702 | if (!map_context->target_request_nr) |
10b8106a MS |
1703 | bio->bi_bdev = s->origin->bdev; |
1704 | else | |
1705 | bio->bi_bdev = s->cow->bdev; | |
1706 | map_context->ptr = NULL; | |
1707 | return DM_MAPIO_REMAPPED; | |
1708 | } | |
1709 | ||
3452c2a1 MP |
1710 | chunk = sector_to_chunk(s->store, bio->bi_sector); |
1711 | ||
9fe86254 | 1712 | down_write(&s->lock); |
3452c2a1 | 1713 | |
d2fdb776 MP |
1714 | /* Full merging snapshots are redirected to the origin */ |
1715 | if (!s->valid) | |
1716 | goto redirect_to_origin; | |
3452c2a1 MP |
1717 | |
1718 | /* If the block is already remapped - use that */ | |
1719 | e = dm_lookup_exception(&s->complete, chunk); | |
1720 | if (e) { | |
9fe86254 MP |
1721 | /* Queue writes overlapping with chunks being merged */ |
1722 | if (bio_rw(bio) == WRITE && | |
1723 | chunk >= s->first_merging_chunk && | |
1724 | chunk < (s->first_merging_chunk + | |
1725 | s->num_merging_chunks)) { | |
1726 | bio->bi_bdev = s->origin->bdev; | |
1727 | bio_list_add(&s->bios_queued_during_merge, bio); | |
1728 | r = DM_MAPIO_SUBMITTED; | |
1729 | goto out_unlock; | |
1730 | } | |
17aa0332 | 1731 | |
3452c2a1 | 1732 | remap_exception(s, e, bio, chunk); |
17aa0332 MP |
1733 | |
1734 | if (bio_rw(bio) == WRITE) | |
1735 | map_context->ptr = track_chunk(s, chunk); | |
3452c2a1 MP |
1736 | goto out_unlock; |
1737 | } | |
1738 | ||
d2fdb776 | 1739 | redirect_to_origin: |
3452c2a1 MP |
1740 | bio->bi_bdev = s->origin->bdev; |
1741 | ||
1742 | if (bio_rw(bio) == WRITE) { | |
9fe86254 | 1743 | up_write(&s->lock); |
3452c2a1 MP |
1744 | return do_origin(s->origin, bio); |
1745 | } | |
1746 | ||
1747 | out_unlock: | |
9fe86254 | 1748 | up_write(&s->lock); |
3452c2a1 MP |
1749 | |
1750 | return r; | |
1751 | } | |
1752 | ||
cd45daff MP |
1753 | static int snapshot_end_io(struct dm_target *ti, struct bio *bio, |
1754 | int error, union map_info *map_context) | |
1755 | { | |
1756 | struct dm_snapshot *s = ti->private; | |
1757 | struct dm_snap_tracked_chunk *c = map_context->ptr; | |
1758 | ||
1759 | if (c) | |
1760 | stop_tracking_chunk(s, c); | |
1761 | ||
1762 | return 0; | |
1763 | } | |
1764 | ||
1e03f97e MP |
1765 | static void snapshot_merge_presuspend(struct dm_target *ti) |
1766 | { | |
1767 | struct dm_snapshot *s = ti->private; | |
1768 | ||
1769 | stop_merge(s); | |
1770 | } | |
1771 | ||
c1f0c183 MS |
1772 | static int snapshot_preresume(struct dm_target *ti) |
1773 | { | |
1774 | int r = 0; | |
1775 | struct dm_snapshot *s = ti->private; | |
1776 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; | |
1777 | ||
1778 | down_read(&_origins_lock); | |
9d3b15c4 | 1779 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1780 | if (snap_src && snap_dest) { |
1781 | down_read(&snap_src->lock); | |
1782 | if (s == snap_src) { | |
1783 | DMERR("Unable to resume snapshot source until " | |
1784 | "handover completes."); | |
1785 | r = -EINVAL; | |
b83b2f29 | 1786 | } else if (!dm_suspended(snap_src->ti)) { |
c1f0c183 MS |
1787 | DMERR("Unable to perform snapshot handover until " |
1788 | "source is suspended."); | |
1789 | r = -EINVAL; | |
1790 | } | |
1791 | up_read(&snap_src->lock); | |
1792 | } | |
1793 | up_read(&_origins_lock); | |
1794 | ||
1795 | return r; | |
1796 | } | |
1797 | ||
1da177e4 LT |
1798 | static void snapshot_resume(struct dm_target *ti) |
1799 | { | |
028867ac | 1800 | struct dm_snapshot *s = ti->private; |
c1f0c183 MS |
1801 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; |
1802 | ||
1803 | down_read(&_origins_lock); | |
9d3b15c4 | 1804 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1805 | if (snap_src && snap_dest) { |
1806 | down_write(&snap_src->lock); | |
1807 | down_write_nested(&snap_dest->lock, SINGLE_DEPTH_NESTING); | |
1808 | __handover_exceptions(snap_src, snap_dest); | |
1809 | up_write(&snap_dest->lock); | |
1810 | up_write(&snap_src->lock); | |
1811 | } | |
1812 | up_read(&_origins_lock); | |
1813 | ||
1814 | /* Now we have correct chunk size, reregister */ | |
1815 | reregister_snapshot(s); | |
1da177e4 | 1816 | |
aa14edeb AK |
1817 | down_write(&s->lock); |
1818 | s->active = 1; | |
1819 | up_write(&s->lock); | |
1da177e4 LT |
1820 | } |
1821 | ||
542f9038 | 1822 | static uint32_t get_origin_minimum_chunksize(struct block_device *bdev) |
1e03f97e | 1823 | { |
542f9038 | 1824 | uint32_t min_chunksize; |
1e03f97e MP |
1825 | |
1826 | down_read(&_origins_lock); | |
1827 | min_chunksize = __minimum_chunk_size(__lookup_origin(bdev)); | |
1828 | up_read(&_origins_lock); | |
1829 | ||
1830 | return min_chunksize; | |
1831 | } | |
1832 | ||
1833 | static void snapshot_merge_resume(struct dm_target *ti) | |
1834 | { | |
1835 | struct dm_snapshot *s = ti->private; | |
1836 | ||
1837 | /* | |
1838 | * Handover exceptions from existing snapshot. | |
1839 | */ | |
1840 | snapshot_resume(ti); | |
1841 | ||
1842 | /* | |
542f9038 | 1843 | * snapshot-merge acts as an origin, so set ti->max_io_len |
1e03f97e | 1844 | */ |
542f9038 | 1845 | ti->max_io_len = get_origin_minimum_chunksize(s->origin->bdev); |
1e03f97e MP |
1846 | |
1847 | start_merge(s); | |
1848 | } | |
1849 | ||
1da177e4 | 1850 | static int snapshot_status(struct dm_target *ti, status_type_t type, |
1f4e0ff0 | 1851 | unsigned status_flags, char *result, unsigned maxlen) |
1da177e4 | 1852 | { |
2e4a31df | 1853 | unsigned sz = 0; |
028867ac | 1854 | struct dm_snapshot *snap = ti->private; |
1da177e4 LT |
1855 | |
1856 | switch (type) { | |
1857 | case STATUSTYPE_INFO: | |
94e76572 MP |
1858 | |
1859 | down_write(&snap->lock); | |
1860 | ||
1da177e4 | 1861 | if (!snap->valid) |
2e4a31df | 1862 | DMEMIT("Invalid"); |
d8ddb1cf MS |
1863 | else if (snap->merge_failed) |
1864 | DMEMIT("Merge failed"); | |
1da177e4 | 1865 | else { |
985903bb MS |
1866 | if (snap->store->type->usage) { |
1867 | sector_t total_sectors, sectors_allocated, | |
1868 | metadata_sectors; | |
1869 | snap->store->type->usage(snap->store, | |
1870 | &total_sectors, | |
1871 | §ors_allocated, | |
1872 | &metadata_sectors); | |
1873 | DMEMIT("%llu/%llu %llu", | |
1874 | (unsigned long long)sectors_allocated, | |
1875 | (unsigned long long)total_sectors, | |
1876 | (unsigned long long)metadata_sectors); | |
1da177e4 LT |
1877 | } |
1878 | else | |
2e4a31df | 1879 | DMEMIT("Unknown"); |
1da177e4 | 1880 | } |
94e76572 MP |
1881 | |
1882 | up_write(&snap->lock); | |
1883 | ||
1da177e4 LT |
1884 | break; |
1885 | ||
1886 | case STATUSTYPE_TABLE: | |
1887 | /* | |
1888 | * kdevname returns a static pointer so we need | |
1889 | * to make private copies if the output is to | |
1890 | * make sense. | |
1891 | */ | |
fc56f6fb | 1892 | DMEMIT("%s %s", snap->origin->name, snap->cow->name); |
1e302a92 JB |
1893 | snap->store->type->status(snap->store, type, result + sz, |
1894 | maxlen - sz); | |
1da177e4 LT |
1895 | break; |
1896 | } | |
1897 | ||
1898 | return 0; | |
1899 | } | |
1900 | ||
8811f46c MS |
1901 | static int snapshot_iterate_devices(struct dm_target *ti, |
1902 | iterate_devices_callout_fn fn, void *data) | |
1903 | { | |
1904 | struct dm_snapshot *snap = ti->private; | |
1e5554c8 MP |
1905 | int r; |
1906 | ||
1907 | r = fn(ti, snap->origin, 0, ti->len, data); | |
8811f46c | 1908 | |
1e5554c8 MP |
1909 | if (!r) |
1910 | r = fn(ti, snap->cow, 0, get_dev_size(snap->cow->bdev), data); | |
1911 | ||
1912 | return r; | |
8811f46c MS |
1913 | } |
1914 | ||
1915 | ||
1da177e4 LT |
1916 | /*----------------------------------------------------------------- |
1917 | * Origin methods | |
1918 | *---------------------------------------------------------------*/ | |
9eaae8ff MP |
1919 | |
1920 | /* | |
1921 | * If no exceptions need creating, DM_MAPIO_REMAPPED is returned and any | |
1922 | * supplied bio was ignored. The caller may submit it immediately. | |
1923 | * (No remapping actually occurs as the origin is always a direct linear | |
1924 | * map.) | |
1925 | * | |
1926 | * If further exceptions are required, DM_MAPIO_SUBMITTED is returned | |
1927 | * and any supplied bio is added to a list to be submitted once all | |
1928 | * the necessary exceptions exist. | |
1929 | */ | |
1930 | static int __origin_write(struct list_head *snapshots, sector_t sector, | |
1931 | struct bio *bio) | |
1da177e4 | 1932 | { |
515ad66c | 1933 | int r = DM_MAPIO_REMAPPED; |
1da177e4 | 1934 | struct dm_snapshot *snap; |
1d4989c8 | 1935 | struct dm_exception *e; |
515ad66c MP |
1936 | struct dm_snap_pending_exception *pe; |
1937 | struct dm_snap_pending_exception *pe_to_start_now = NULL; | |
1938 | struct dm_snap_pending_exception *pe_to_start_last = NULL; | |
1da177e4 LT |
1939 | chunk_t chunk; |
1940 | ||
1941 | /* Do all the snapshots on this origin */ | |
1942 | list_for_each_entry (snap, snapshots, list) { | |
3452c2a1 MP |
1943 | /* |
1944 | * Don't make new exceptions in a merging snapshot | |
1945 | * because it has effectively been deleted | |
1946 | */ | |
1947 | if (dm_target_is_snapshot_merge(snap->ti)) | |
1948 | continue; | |
1949 | ||
76df1c65 AK |
1950 | down_write(&snap->lock); |
1951 | ||
aa14edeb AK |
1952 | /* Only deal with valid and active snapshots */ |
1953 | if (!snap->valid || !snap->active) | |
76df1c65 | 1954 | goto next_snapshot; |
1da177e4 | 1955 | |
d5e404c1 | 1956 | /* Nothing to do if writing beyond end of snapshot */ |
9eaae8ff | 1957 | if (sector >= dm_table_get_size(snap->ti->table)) |
76df1c65 | 1958 | goto next_snapshot; |
1da177e4 LT |
1959 | |
1960 | /* | |
1961 | * Remember, different snapshots can have | |
1962 | * different chunk sizes. | |
1963 | */ | |
9eaae8ff | 1964 | chunk = sector_to_chunk(snap->store, sector); |
1da177e4 LT |
1965 | |
1966 | /* | |
1967 | * Check exception table to see if block | |
1968 | * is already remapped in this snapshot | |
1969 | * and trigger an exception if not. | |
1970 | */ | |
3510cb94 | 1971 | e = dm_lookup_exception(&snap->complete, chunk); |
76df1c65 AK |
1972 | if (e) |
1973 | goto next_snapshot; | |
1974 | ||
2913808e | 1975 | pe = __lookup_pending_exception(snap, chunk); |
76df1c65 | 1976 | if (!pe) { |
c6621392 MP |
1977 | up_write(&snap->lock); |
1978 | pe = alloc_pending_exception(snap); | |
1979 | down_write(&snap->lock); | |
1980 | ||
1981 | if (!snap->valid) { | |
1982 | free_pending_exception(pe); | |
1983 | goto next_snapshot; | |
1984 | } | |
1985 | ||
3510cb94 | 1986 | e = dm_lookup_exception(&snap->complete, chunk); |
35bf659b MP |
1987 | if (e) { |
1988 | free_pending_exception(pe); | |
1989 | goto next_snapshot; | |
1990 | } | |
1991 | ||
c6621392 | 1992 | pe = __find_pending_exception(snap, pe, chunk); |
2913808e MP |
1993 | if (!pe) { |
1994 | __invalidate_snapshot(snap, -ENOMEM); | |
1995 | goto next_snapshot; | |
1996 | } | |
76df1c65 AK |
1997 | } |
1998 | ||
515ad66c | 1999 | r = DM_MAPIO_SUBMITTED; |
76df1c65 | 2000 | |
515ad66c MP |
2001 | /* |
2002 | * If an origin bio was supplied, queue it to wait for the | |
2003 | * completion of this exception, and start this one last, | |
2004 | * at the end of the function. | |
2005 | */ | |
2006 | if (bio) { | |
2007 | bio_list_add(&pe->origin_bios, bio); | |
2008 | bio = NULL; | |
76df1c65 | 2009 | |
515ad66c MP |
2010 | if (!pe->started) { |
2011 | pe->started = 1; | |
2012 | pe_to_start_last = pe; | |
2013 | } | |
76df1c65 AK |
2014 | } |
2015 | ||
2016 | if (!pe->started) { | |
2017 | pe->started = 1; | |
515ad66c | 2018 | pe_to_start_now = pe; |
1da177e4 LT |
2019 | } |
2020 | ||
a2d2b034 | 2021 | next_snapshot: |
1da177e4 | 2022 | up_write(&snap->lock); |
1da177e4 | 2023 | |
515ad66c MP |
2024 | if (pe_to_start_now) { |
2025 | start_copy(pe_to_start_now); | |
2026 | pe_to_start_now = NULL; | |
2027 | } | |
b4b610f6 AK |
2028 | } |
2029 | ||
1da177e4 | 2030 | /* |
515ad66c MP |
2031 | * Submit the exception against which the bio is queued last, |
2032 | * to give the other exceptions a head start. | |
1da177e4 | 2033 | */ |
515ad66c MP |
2034 | if (pe_to_start_last) |
2035 | start_copy(pe_to_start_last); | |
1da177e4 LT |
2036 | |
2037 | return r; | |
2038 | } | |
2039 | ||
2040 | /* | |
2041 | * Called on a write from the origin driver. | |
2042 | */ | |
2043 | static int do_origin(struct dm_dev *origin, struct bio *bio) | |
2044 | { | |
2045 | struct origin *o; | |
d2a7ad29 | 2046 | int r = DM_MAPIO_REMAPPED; |
1da177e4 LT |
2047 | |
2048 | down_read(&_origins_lock); | |
2049 | o = __lookup_origin(origin->bdev); | |
2050 | if (o) | |
9eaae8ff | 2051 | r = __origin_write(&o->snapshots, bio->bi_sector, bio); |
1da177e4 LT |
2052 | up_read(&_origins_lock); |
2053 | ||
2054 | return r; | |
2055 | } | |
2056 | ||
73dfd078 MP |
2057 | /* |
2058 | * Trigger exceptions in all non-merging snapshots. | |
2059 | * | |
2060 | * The chunk size of the merging snapshot may be larger than the chunk | |
2061 | * size of some other snapshot so we may need to reallocate multiple | |
2062 | * chunks in other snapshots. | |
2063 | * | |
2064 | * We scan all the overlapping exceptions in the other snapshots. | |
2065 | * Returns 1 if anything was reallocated and must be waited for, | |
2066 | * otherwise returns 0. | |
2067 | * | |
2068 | * size must be a multiple of merging_snap's chunk_size. | |
2069 | */ | |
2070 | static int origin_write_extent(struct dm_snapshot *merging_snap, | |
2071 | sector_t sector, unsigned size) | |
2072 | { | |
2073 | int must_wait = 0; | |
2074 | sector_t n; | |
2075 | struct origin *o; | |
2076 | ||
2077 | /* | |
542f9038 | 2078 | * The origin's __minimum_chunk_size() got stored in max_io_len |
73dfd078 MP |
2079 | * by snapshot_merge_resume(). |
2080 | */ | |
2081 | down_read(&_origins_lock); | |
2082 | o = __lookup_origin(merging_snap->origin->bdev); | |
542f9038 | 2083 | for (n = 0; n < size; n += merging_snap->ti->max_io_len) |
73dfd078 MP |
2084 | if (__origin_write(&o->snapshots, sector + n, NULL) == |
2085 | DM_MAPIO_SUBMITTED) | |
2086 | must_wait = 1; | |
2087 | up_read(&_origins_lock); | |
2088 | ||
2089 | return must_wait; | |
2090 | } | |
2091 | ||
1da177e4 LT |
2092 | /* |
2093 | * Origin: maps a linear range of a device, with hooks for snapshotting. | |
2094 | */ | |
2095 | ||
2096 | /* | |
2097 | * Construct an origin mapping: <dev_path> | |
2098 | * The context for an origin is merely a 'struct dm_dev *' | |
2099 | * pointing to the real device. | |
2100 | */ | |
2101 | static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
2102 | { | |
2103 | int r; | |
2104 | struct dm_dev *dev; | |
2105 | ||
2106 | if (argc != 1) { | |
72d94861 | 2107 | ti->error = "origin: incorrect number of arguments"; |
1da177e4 LT |
2108 | return -EINVAL; |
2109 | } | |
2110 | ||
8215d6ec | 2111 | r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev); |
1da177e4 LT |
2112 | if (r) { |
2113 | ti->error = "Cannot get target device"; | |
2114 | return r; | |
2115 | } | |
2116 | ||
2117 | ti->private = dev; | |
494b3ee7 MP |
2118 | ti->num_flush_requests = 1; |
2119 | ||
1da177e4 LT |
2120 | return 0; |
2121 | } | |
2122 | ||
2123 | static void origin_dtr(struct dm_target *ti) | |
2124 | { | |
028867ac | 2125 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2126 | dm_put_device(ti, dev); |
2127 | } | |
2128 | ||
2129 | static int origin_map(struct dm_target *ti, struct bio *bio, | |
2130 | union map_info *map_context) | |
2131 | { | |
028867ac | 2132 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2133 | bio->bi_bdev = dev->bdev; |
2134 | ||
d87f4c14 | 2135 | if (bio->bi_rw & REQ_FLUSH) |
494b3ee7 MP |
2136 | return DM_MAPIO_REMAPPED; |
2137 | ||
1da177e4 | 2138 | /* Only tell snapshots if this is a write */ |
d2a7ad29 | 2139 | return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; |
1da177e4 LT |
2140 | } |
2141 | ||
1da177e4 | 2142 | /* |
542f9038 | 2143 | * Set the target "max_io_len" field to the minimum of all the snapshots' |
1da177e4 LT |
2144 | * chunk sizes. |
2145 | */ | |
2146 | static void origin_resume(struct dm_target *ti) | |
2147 | { | |
028867ac | 2148 | struct dm_dev *dev = ti->private; |
1da177e4 | 2149 | |
542f9038 | 2150 | ti->max_io_len = get_origin_minimum_chunksize(dev->bdev); |
1da177e4 LT |
2151 | } |
2152 | ||
1f4e0ff0 AK |
2153 | static int origin_status(struct dm_target *ti, status_type_t type, |
2154 | unsigned status_flags, char *result, unsigned maxlen) | |
1da177e4 | 2155 | { |
028867ac | 2156 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2157 | |
2158 | switch (type) { | |
2159 | case STATUSTYPE_INFO: | |
2160 | result[0] = '\0'; | |
2161 | break; | |
2162 | ||
2163 | case STATUSTYPE_TABLE: | |
2164 | snprintf(result, maxlen, "%s", dev->name); | |
2165 | break; | |
2166 | } | |
2167 | ||
2168 | return 0; | |
2169 | } | |
2170 | ||
b1d55528 MP |
2171 | static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
2172 | struct bio_vec *biovec, int max_size) | |
2173 | { | |
2174 | struct dm_dev *dev = ti->private; | |
2175 | struct request_queue *q = bdev_get_queue(dev->bdev); | |
2176 | ||
2177 | if (!q->merge_bvec_fn) | |
2178 | return max_size; | |
2179 | ||
2180 | bvm->bi_bdev = dev->bdev; | |
b1d55528 MP |
2181 | |
2182 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
2183 | } | |
2184 | ||
8811f46c MS |
2185 | static int origin_iterate_devices(struct dm_target *ti, |
2186 | iterate_devices_callout_fn fn, void *data) | |
2187 | { | |
2188 | struct dm_dev *dev = ti->private; | |
2189 | ||
2190 | return fn(ti, dev, 0, ti->len, data); | |
2191 | } | |
2192 | ||
1da177e4 LT |
2193 | static struct target_type origin_target = { |
2194 | .name = "snapshot-origin", | |
b83b2f29 | 2195 | .version = {1, 7, 1}, |
1da177e4 LT |
2196 | .module = THIS_MODULE, |
2197 | .ctr = origin_ctr, | |
2198 | .dtr = origin_dtr, | |
2199 | .map = origin_map, | |
2200 | .resume = origin_resume, | |
2201 | .status = origin_status, | |
b1d55528 | 2202 | .merge = origin_merge, |
8811f46c | 2203 | .iterate_devices = origin_iterate_devices, |
1da177e4 LT |
2204 | }; |
2205 | ||
2206 | static struct target_type snapshot_target = { | |
2207 | .name = "snapshot", | |
b83b2f29 | 2208 | .version = {1, 10, 0}, |
1da177e4 LT |
2209 | .module = THIS_MODULE, |
2210 | .ctr = snapshot_ctr, | |
2211 | .dtr = snapshot_dtr, | |
2212 | .map = snapshot_map, | |
cd45daff | 2213 | .end_io = snapshot_end_io, |
c1f0c183 | 2214 | .preresume = snapshot_preresume, |
1da177e4 LT |
2215 | .resume = snapshot_resume, |
2216 | .status = snapshot_status, | |
8811f46c | 2217 | .iterate_devices = snapshot_iterate_devices, |
1da177e4 LT |
2218 | }; |
2219 | ||
d698aa45 MP |
2220 | static struct target_type merge_target = { |
2221 | .name = dm_snapshot_merge_target_name, | |
b83b2f29 | 2222 | .version = {1, 1, 0}, |
d698aa45 MP |
2223 | .module = THIS_MODULE, |
2224 | .ctr = snapshot_ctr, | |
2225 | .dtr = snapshot_dtr, | |
3452c2a1 | 2226 | .map = snapshot_merge_map, |
d698aa45 | 2227 | .end_io = snapshot_end_io, |
1e03f97e | 2228 | .presuspend = snapshot_merge_presuspend, |
d698aa45 | 2229 | .preresume = snapshot_preresume, |
1e03f97e | 2230 | .resume = snapshot_merge_resume, |
d698aa45 MP |
2231 | .status = snapshot_status, |
2232 | .iterate_devices = snapshot_iterate_devices, | |
2233 | }; | |
2234 | ||
1da177e4 LT |
2235 | static int __init dm_snapshot_init(void) |
2236 | { | |
2237 | int r; | |
2238 | ||
4db6bfe0 AK |
2239 | r = dm_exception_store_init(); |
2240 | if (r) { | |
2241 | DMERR("Failed to initialize exception stores"); | |
2242 | return r; | |
2243 | } | |
2244 | ||
1da177e4 | 2245 | r = dm_register_target(&snapshot_target); |
d698aa45 | 2246 | if (r < 0) { |
1da177e4 | 2247 | DMERR("snapshot target register failed %d", r); |
034a186d | 2248 | goto bad_register_snapshot_target; |
1da177e4 LT |
2249 | } |
2250 | ||
2251 | r = dm_register_target(&origin_target); | |
2252 | if (r < 0) { | |
72d94861 | 2253 | DMERR("Origin target register failed %d", r); |
d698aa45 MP |
2254 | goto bad_register_origin_target; |
2255 | } | |
2256 | ||
2257 | r = dm_register_target(&merge_target); | |
2258 | if (r < 0) { | |
2259 | DMERR("Merge target register failed %d", r); | |
2260 | goto bad_register_merge_target; | |
1da177e4 LT |
2261 | } |
2262 | ||
2263 | r = init_origin_hash(); | |
2264 | if (r) { | |
2265 | DMERR("init_origin_hash failed."); | |
d698aa45 | 2266 | goto bad_origin_hash; |
1da177e4 LT |
2267 | } |
2268 | ||
1d4989c8 | 2269 | exception_cache = KMEM_CACHE(dm_exception, 0); |
1da177e4 LT |
2270 | if (!exception_cache) { |
2271 | DMERR("Couldn't create exception cache."); | |
2272 | r = -ENOMEM; | |
d698aa45 | 2273 | goto bad_exception_cache; |
1da177e4 LT |
2274 | } |
2275 | ||
028867ac | 2276 | pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0); |
1da177e4 LT |
2277 | if (!pending_cache) { |
2278 | DMERR("Couldn't create pending cache."); | |
2279 | r = -ENOMEM; | |
d698aa45 | 2280 | goto bad_pending_cache; |
1da177e4 LT |
2281 | } |
2282 | ||
cd45daff MP |
2283 | tracked_chunk_cache = KMEM_CACHE(dm_snap_tracked_chunk, 0); |
2284 | if (!tracked_chunk_cache) { | |
2285 | DMERR("Couldn't create cache to track chunks in use."); | |
2286 | r = -ENOMEM; | |
d698aa45 | 2287 | goto bad_tracked_chunk_cache; |
cd45daff MP |
2288 | } |
2289 | ||
1da177e4 LT |
2290 | return 0; |
2291 | ||
d698aa45 | 2292 | bad_tracked_chunk_cache: |
1da177e4 | 2293 | kmem_cache_destroy(pending_cache); |
d698aa45 | 2294 | bad_pending_cache: |
1da177e4 | 2295 | kmem_cache_destroy(exception_cache); |
d698aa45 | 2296 | bad_exception_cache: |
1da177e4 | 2297 | exit_origin_hash(); |
d698aa45 MP |
2298 | bad_origin_hash: |
2299 | dm_unregister_target(&merge_target); | |
2300 | bad_register_merge_target: | |
1da177e4 | 2301 | dm_unregister_target(&origin_target); |
d698aa45 | 2302 | bad_register_origin_target: |
1da177e4 | 2303 | dm_unregister_target(&snapshot_target); |
034a186d JB |
2304 | bad_register_snapshot_target: |
2305 | dm_exception_store_exit(); | |
d698aa45 | 2306 | |
1da177e4 LT |
2307 | return r; |
2308 | } | |
2309 | ||
2310 | static void __exit dm_snapshot_exit(void) | |
2311 | { | |
10d3bd09 MP |
2312 | dm_unregister_target(&snapshot_target); |
2313 | dm_unregister_target(&origin_target); | |
d698aa45 | 2314 | dm_unregister_target(&merge_target); |
1da177e4 LT |
2315 | |
2316 | exit_origin_hash(); | |
1da177e4 LT |
2317 | kmem_cache_destroy(pending_cache); |
2318 | kmem_cache_destroy(exception_cache); | |
cd45daff | 2319 | kmem_cache_destroy(tracked_chunk_cache); |
4db6bfe0 AK |
2320 | |
2321 | dm_exception_store_exit(); | |
1da177e4 LT |
2322 | } |
2323 | ||
2324 | /* Module hooks */ | |
2325 | module_init(dm_snapshot_init); | |
2326 | module_exit(dm_snapshot_exit); | |
2327 | ||
2328 | MODULE_DESCRIPTION(DM_NAME " snapshot target"); | |
2329 | MODULE_AUTHOR("Joe Thornber"); | |
2330 | MODULE_LICENSE("GPL"); |