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; | |
924e600d MS |
82 | struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE]; |
83 | ||
ccc45ea8 JB |
84 | /* The on disk metadata handler */ |
85 | struct dm_exception_store *store; | |
86 | ||
87 | struct dm_kcopyd_client *kcopyd_client; | |
88 | ||
924e600d MS |
89 | /* Wait for events based on state_bits */ |
90 | unsigned long state_bits; | |
91 | ||
92 | /* Range of chunks currently being merged. */ | |
93 | chunk_t first_merging_chunk; | |
94 | int num_merging_chunks; | |
1e03f97e | 95 | |
d8ddb1cf MS |
96 | /* |
97 | * The merge operation failed if this flag is set. | |
98 | * Failure modes are handled as follows: | |
99 | * - I/O error reading the header | |
100 | * => don't load the target; abort. | |
101 | * - Header does not have "valid" flag set | |
102 | * => use the origin; forget about the snapshot. | |
103 | * - I/O error when reading exceptions | |
104 | * => don't load the target; abort. | |
105 | * (We can't use the intermediate origin state.) | |
106 | * - I/O error while merging | |
107 | * => stop merging; set merge_failed; process I/O normally. | |
108 | */ | |
109 | int merge_failed; | |
110 | ||
9fe86254 MP |
111 | /* |
112 | * Incoming bios that overlap with chunks being merged must wait | |
113 | * for them to be committed. | |
114 | */ | |
115 | struct bio_list bios_queued_during_merge; | |
ccc45ea8 JB |
116 | }; |
117 | ||
1e03f97e MP |
118 | /* |
119 | * state_bits: | |
120 | * RUNNING_MERGE - Merge operation is in progress. | |
121 | * SHUTDOWN_MERGE - Set to signal that merge needs to be stopped; | |
122 | * cleared afterwards. | |
123 | */ | |
124 | #define RUNNING_MERGE 0 | |
125 | #define SHUTDOWN_MERGE 1 | |
126 | ||
df5d2e90 MP |
127 | DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle, |
128 | "A percentage of time allocated for copy on write"); | |
129 | ||
c2411045 MP |
130 | struct dm_dev *dm_snap_origin(struct dm_snapshot *s) |
131 | { | |
132 | return s->origin; | |
133 | } | |
134 | EXPORT_SYMBOL(dm_snap_origin); | |
135 | ||
fc56f6fb MS |
136 | struct dm_dev *dm_snap_cow(struct dm_snapshot *s) |
137 | { | |
138 | return s->cow; | |
139 | } | |
140 | EXPORT_SYMBOL(dm_snap_cow); | |
141 | ||
ccc45ea8 JB |
142 | static sector_t chunk_to_sector(struct dm_exception_store *store, |
143 | chunk_t chunk) | |
144 | { | |
145 | return chunk << store->chunk_shift; | |
146 | } | |
147 | ||
148 | static int bdev_equal(struct block_device *lhs, struct block_device *rhs) | |
149 | { | |
150 | /* | |
151 | * There is only ever one instance of a particular block | |
152 | * device so we can compare pointers safely. | |
153 | */ | |
154 | return lhs == rhs; | |
155 | } | |
156 | ||
028867ac | 157 | struct dm_snap_pending_exception { |
1d4989c8 | 158 | struct dm_exception e; |
1da177e4 LT |
159 | |
160 | /* | |
161 | * Origin buffers waiting for this to complete are held | |
162 | * in a bio list | |
163 | */ | |
164 | struct bio_list origin_bios; | |
165 | struct bio_list snapshot_bios; | |
166 | ||
1da177e4 LT |
167 | /* Pointer back to snapshot context */ |
168 | struct dm_snapshot *snap; | |
169 | ||
170 | /* | |
171 | * 1 indicates the exception has already been sent to | |
172 | * kcopyd. | |
173 | */ | |
174 | int started; | |
a6e50b40 MP |
175 | |
176 | /* | |
177 | * For writing a complete chunk, bypassing the copy. | |
178 | */ | |
179 | struct bio *full_bio; | |
180 | bio_end_io_t *full_bio_end_io; | |
181 | void *full_bio_private; | |
1da177e4 LT |
182 | }; |
183 | ||
184 | /* | |
185 | * Hash table mapping origin volumes to lists of snapshots and | |
186 | * a lock to protect it | |
187 | */ | |
e18b890b CL |
188 | static struct kmem_cache *exception_cache; |
189 | static struct kmem_cache *pending_cache; | |
1da177e4 | 190 | |
cd45daff MP |
191 | struct dm_snap_tracked_chunk { |
192 | struct hlist_node node; | |
193 | chunk_t chunk; | |
194 | }; | |
195 | ||
ee18026a MP |
196 | static void init_tracked_chunk(struct bio *bio) |
197 | { | |
198 | struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk)); | |
199 | INIT_HLIST_NODE(&c->node); | |
200 | } | |
201 | ||
202 | static bool is_bio_tracked(struct bio *bio) | |
203 | { | |
204 | struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk)); | |
205 | return !hlist_unhashed(&c->node); | |
206 | } | |
207 | ||
208 | static void track_chunk(struct dm_snapshot *s, struct bio *bio, chunk_t chunk) | |
cd45daff | 209 | { |
42bc954f | 210 | struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk)); |
cd45daff MP |
211 | |
212 | c->chunk = chunk; | |
213 | ||
9aa0c0e6 | 214 | spin_lock_irq(&s->tracked_chunk_lock); |
cd45daff MP |
215 | hlist_add_head(&c->node, |
216 | &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)]); | |
9aa0c0e6 | 217 | spin_unlock_irq(&s->tracked_chunk_lock); |
cd45daff MP |
218 | } |
219 | ||
ee18026a | 220 | static void stop_tracking_chunk(struct dm_snapshot *s, struct bio *bio) |
cd45daff | 221 | { |
ee18026a | 222 | struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk)); |
cd45daff MP |
223 | unsigned long flags; |
224 | ||
225 | spin_lock_irqsave(&s->tracked_chunk_lock, flags); | |
226 | hlist_del(&c->node); | |
227 | spin_unlock_irqrestore(&s->tracked_chunk_lock, flags); | |
cd45daff MP |
228 | } |
229 | ||
a8d41b59 MP |
230 | static int __chunk_is_tracked(struct dm_snapshot *s, chunk_t chunk) |
231 | { | |
232 | struct dm_snap_tracked_chunk *c; | |
a8d41b59 MP |
233 | int found = 0; |
234 | ||
235 | spin_lock_irq(&s->tracked_chunk_lock); | |
236 | ||
b67bfe0d | 237 | hlist_for_each_entry(c, |
a8d41b59 MP |
238 | &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)], node) { |
239 | if (c->chunk == chunk) { | |
240 | found = 1; | |
241 | break; | |
242 | } | |
243 | } | |
244 | ||
245 | spin_unlock_irq(&s->tracked_chunk_lock); | |
246 | ||
247 | return found; | |
248 | } | |
249 | ||
615d1eb9 MS |
250 | /* |
251 | * This conflicting I/O is extremely improbable in the caller, | |
252 | * so msleep(1) is sufficient and there is no need for a wait queue. | |
253 | */ | |
254 | static void __check_for_conflicting_io(struct dm_snapshot *s, chunk_t chunk) | |
255 | { | |
256 | while (__chunk_is_tracked(s, chunk)) | |
257 | msleep(1); | |
258 | } | |
259 | ||
1da177e4 LT |
260 | /* |
261 | * One of these per registered origin, held in the snapshot_origins hash | |
262 | */ | |
263 | struct origin { | |
264 | /* The origin device */ | |
265 | struct block_device *bdev; | |
266 | ||
267 | struct list_head hash_list; | |
268 | ||
269 | /* List of snapshots for this origin */ | |
270 | struct list_head snapshots; | |
271 | }; | |
272 | ||
273 | /* | |
274 | * Size of the hash table for origin volumes. If we make this | |
275 | * the size of the minors list then it should be nearly perfect | |
276 | */ | |
277 | #define ORIGIN_HASH_SIZE 256 | |
278 | #define ORIGIN_MASK 0xFF | |
279 | static struct list_head *_origins; | |
280 | static struct rw_semaphore _origins_lock; | |
281 | ||
73dfd078 MP |
282 | static DECLARE_WAIT_QUEUE_HEAD(_pending_exceptions_done); |
283 | static DEFINE_SPINLOCK(_pending_exceptions_done_spinlock); | |
284 | static uint64_t _pending_exceptions_done_count; | |
285 | ||
1da177e4 LT |
286 | static int init_origin_hash(void) |
287 | { | |
288 | int i; | |
289 | ||
290 | _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), | |
291 | GFP_KERNEL); | |
292 | if (!_origins) { | |
72d94861 | 293 | DMERR("unable to allocate memory"); |
1da177e4 LT |
294 | return -ENOMEM; |
295 | } | |
296 | ||
297 | for (i = 0; i < ORIGIN_HASH_SIZE; i++) | |
298 | INIT_LIST_HEAD(_origins + i); | |
299 | init_rwsem(&_origins_lock); | |
300 | ||
301 | return 0; | |
302 | } | |
303 | ||
304 | static void exit_origin_hash(void) | |
305 | { | |
306 | kfree(_origins); | |
307 | } | |
308 | ||
028867ac | 309 | static unsigned origin_hash(struct block_device *bdev) |
1da177e4 LT |
310 | { |
311 | return bdev->bd_dev & ORIGIN_MASK; | |
312 | } | |
313 | ||
314 | static struct origin *__lookup_origin(struct block_device *origin) | |
315 | { | |
316 | struct list_head *ol; | |
317 | struct origin *o; | |
318 | ||
319 | ol = &_origins[origin_hash(origin)]; | |
320 | list_for_each_entry (o, ol, hash_list) | |
321 | if (bdev_equal(o->bdev, origin)) | |
322 | return o; | |
323 | ||
324 | return NULL; | |
325 | } | |
326 | ||
327 | static void __insert_origin(struct origin *o) | |
328 | { | |
329 | struct list_head *sl = &_origins[origin_hash(o->bdev)]; | |
330 | list_add_tail(&o->hash_list, sl); | |
331 | } | |
332 | ||
c1f0c183 MS |
333 | /* |
334 | * _origins_lock must be held when calling this function. | |
335 | * Returns number of snapshots registered using the supplied cow device, plus: | |
336 | * snap_src - a snapshot suitable for use as a source of exception handover | |
337 | * snap_dest - a snapshot capable of receiving exception handover. | |
9d3b15c4 MP |
338 | * snap_merge - an existing snapshot-merge target linked to the same origin. |
339 | * There can be at most one snapshot-merge target. The parameter is optional. | |
c1f0c183 | 340 | * |
9d3b15c4 | 341 | * Possible return values and states of snap_src and snap_dest. |
c1f0c183 MS |
342 | * 0: NULL, NULL - first new snapshot |
343 | * 1: snap_src, NULL - normal snapshot | |
344 | * 2: snap_src, snap_dest - waiting for handover | |
345 | * 2: snap_src, NULL - handed over, waiting for old to be deleted | |
346 | * 1: NULL, snap_dest - source got destroyed without handover | |
347 | */ | |
348 | static int __find_snapshots_sharing_cow(struct dm_snapshot *snap, | |
349 | struct dm_snapshot **snap_src, | |
9d3b15c4 MP |
350 | struct dm_snapshot **snap_dest, |
351 | struct dm_snapshot **snap_merge) | |
c1f0c183 MS |
352 | { |
353 | struct dm_snapshot *s; | |
354 | struct origin *o; | |
355 | int count = 0; | |
356 | int active; | |
357 | ||
358 | o = __lookup_origin(snap->origin->bdev); | |
359 | if (!o) | |
360 | goto out; | |
361 | ||
362 | list_for_each_entry(s, &o->snapshots, list) { | |
9d3b15c4 MP |
363 | if (dm_target_is_snapshot_merge(s->ti) && snap_merge) |
364 | *snap_merge = s; | |
c1f0c183 MS |
365 | if (!bdev_equal(s->cow->bdev, snap->cow->bdev)) |
366 | continue; | |
367 | ||
368 | down_read(&s->lock); | |
369 | active = s->active; | |
370 | up_read(&s->lock); | |
371 | ||
372 | if (active) { | |
373 | if (snap_src) | |
374 | *snap_src = s; | |
375 | } else if (snap_dest) | |
376 | *snap_dest = s; | |
377 | ||
378 | count++; | |
379 | } | |
380 | ||
381 | out: | |
382 | return count; | |
383 | } | |
384 | ||
385 | /* | |
386 | * On success, returns 1 if this snapshot is a handover destination, | |
387 | * otherwise returns 0. | |
388 | */ | |
389 | static int __validate_exception_handover(struct dm_snapshot *snap) | |
390 | { | |
391 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; | |
9d3b15c4 | 392 | struct dm_snapshot *snap_merge = NULL; |
c1f0c183 MS |
393 | |
394 | /* Does snapshot need exceptions handed over to it? */ | |
9d3b15c4 MP |
395 | if ((__find_snapshots_sharing_cow(snap, &snap_src, &snap_dest, |
396 | &snap_merge) == 2) || | |
c1f0c183 MS |
397 | snap_dest) { |
398 | snap->ti->error = "Snapshot cow pairing for exception " | |
399 | "table handover failed"; | |
400 | return -EINVAL; | |
401 | } | |
402 | ||
403 | /* | |
404 | * If no snap_src was found, snap cannot become a handover | |
405 | * destination. | |
406 | */ | |
407 | if (!snap_src) | |
408 | return 0; | |
409 | ||
9d3b15c4 MP |
410 | /* |
411 | * Non-snapshot-merge handover? | |
412 | */ | |
413 | if (!dm_target_is_snapshot_merge(snap->ti)) | |
414 | return 1; | |
415 | ||
416 | /* | |
417 | * Do not allow more than one merging snapshot. | |
418 | */ | |
419 | if (snap_merge) { | |
420 | snap->ti->error = "A snapshot is already merging."; | |
421 | return -EINVAL; | |
422 | } | |
423 | ||
1e03f97e MP |
424 | if (!snap_src->store->type->prepare_merge || |
425 | !snap_src->store->type->commit_merge) { | |
426 | snap->ti->error = "Snapshot exception store does not " | |
427 | "support snapshot-merge."; | |
428 | return -EINVAL; | |
429 | } | |
430 | ||
c1f0c183 MS |
431 | return 1; |
432 | } | |
433 | ||
434 | static void __insert_snapshot(struct origin *o, struct dm_snapshot *s) | |
435 | { | |
436 | struct dm_snapshot *l; | |
437 | ||
438 | /* Sort the list according to chunk size, largest-first smallest-last */ | |
439 | list_for_each_entry(l, &o->snapshots, list) | |
440 | if (l->store->chunk_size < s->store->chunk_size) | |
441 | break; | |
442 | list_add_tail(&s->list, &l->list); | |
443 | } | |
444 | ||
1da177e4 LT |
445 | /* |
446 | * Make a note of the snapshot and its origin so we can look it | |
447 | * up when the origin has a write on it. | |
c1f0c183 MS |
448 | * |
449 | * Also validate snapshot exception store handovers. | |
450 | * On success, returns 1 if this registration is a handover destination, | |
451 | * otherwise returns 0. | |
1da177e4 LT |
452 | */ |
453 | static int register_snapshot(struct dm_snapshot *snap) | |
454 | { | |
c1f0c183 | 455 | struct origin *o, *new_o = NULL; |
1da177e4 | 456 | struct block_device *bdev = snap->origin->bdev; |
c1f0c183 | 457 | int r = 0; |
1da177e4 | 458 | |
60c856c8 MP |
459 | new_o = kmalloc(sizeof(*new_o), GFP_KERNEL); |
460 | if (!new_o) | |
461 | return -ENOMEM; | |
462 | ||
1da177e4 | 463 | down_write(&_origins_lock); |
1da177e4 | 464 | |
c1f0c183 MS |
465 | r = __validate_exception_handover(snap); |
466 | if (r < 0) { | |
467 | kfree(new_o); | |
468 | goto out; | |
469 | } | |
470 | ||
471 | o = __lookup_origin(bdev); | |
60c856c8 MP |
472 | if (o) |
473 | kfree(new_o); | |
474 | else { | |
1da177e4 | 475 | /* New origin */ |
60c856c8 | 476 | o = new_o; |
1da177e4 LT |
477 | |
478 | /* Initialise the struct */ | |
479 | INIT_LIST_HEAD(&o->snapshots); | |
480 | o->bdev = bdev; | |
481 | ||
482 | __insert_origin(o); | |
483 | } | |
484 | ||
c1f0c183 MS |
485 | __insert_snapshot(o, snap); |
486 | ||
487 | out: | |
488 | up_write(&_origins_lock); | |
489 | ||
490 | return r; | |
491 | } | |
492 | ||
493 | /* | |
494 | * Move snapshot to correct place in list according to chunk size. | |
495 | */ | |
496 | static void reregister_snapshot(struct dm_snapshot *s) | |
497 | { | |
498 | struct block_device *bdev = s->origin->bdev; | |
499 | ||
500 | down_write(&_origins_lock); | |
501 | ||
502 | list_del(&s->list); | |
503 | __insert_snapshot(__lookup_origin(bdev), s); | |
1da177e4 LT |
504 | |
505 | up_write(&_origins_lock); | |
1da177e4 LT |
506 | } |
507 | ||
508 | static void unregister_snapshot(struct dm_snapshot *s) | |
509 | { | |
510 | struct origin *o; | |
511 | ||
512 | down_write(&_origins_lock); | |
513 | o = __lookup_origin(s->origin->bdev); | |
514 | ||
515 | list_del(&s->list); | |
c1f0c183 | 516 | if (o && list_empty(&o->snapshots)) { |
1da177e4 LT |
517 | list_del(&o->hash_list); |
518 | kfree(o); | |
519 | } | |
520 | ||
521 | up_write(&_origins_lock); | |
522 | } | |
523 | ||
524 | /* | |
525 | * Implementation of the exception hash tables. | |
d74f81f8 MB |
526 | * The lowest hash_shift bits of the chunk number are ignored, allowing |
527 | * some consecutive chunks to be grouped together. | |
1da177e4 | 528 | */ |
3510cb94 JB |
529 | static int dm_exception_table_init(struct dm_exception_table *et, |
530 | uint32_t size, unsigned hash_shift) | |
1da177e4 LT |
531 | { |
532 | unsigned int i; | |
533 | ||
d74f81f8 | 534 | et->hash_shift = hash_shift; |
1da177e4 LT |
535 | et->hash_mask = size - 1; |
536 | et->table = dm_vcalloc(size, sizeof(struct list_head)); | |
537 | if (!et->table) | |
538 | return -ENOMEM; | |
539 | ||
540 | for (i = 0; i < size; i++) | |
541 | INIT_LIST_HEAD(et->table + i); | |
542 | ||
543 | return 0; | |
544 | } | |
545 | ||
3510cb94 JB |
546 | static void dm_exception_table_exit(struct dm_exception_table *et, |
547 | struct kmem_cache *mem) | |
1da177e4 LT |
548 | { |
549 | struct list_head *slot; | |
1d4989c8 | 550 | struct dm_exception *ex, *next; |
1da177e4 LT |
551 | int i, size; |
552 | ||
553 | size = et->hash_mask + 1; | |
554 | for (i = 0; i < size; i++) { | |
555 | slot = et->table + i; | |
556 | ||
557 | list_for_each_entry_safe (ex, next, slot, hash_list) | |
558 | kmem_cache_free(mem, ex); | |
559 | } | |
560 | ||
561 | vfree(et->table); | |
562 | } | |
563 | ||
191437a5 | 564 | static uint32_t exception_hash(struct dm_exception_table *et, chunk_t chunk) |
1da177e4 | 565 | { |
d74f81f8 | 566 | return (chunk >> et->hash_shift) & et->hash_mask; |
1da177e4 LT |
567 | } |
568 | ||
3510cb94 | 569 | static void dm_remove_exception(struct dm_exception *e) |
1da177e4 LT |
570 | { |
571 | list_del(&e->hash_list); | |
572 | } | |
573 | ||
574 | /* | |
575 | * Return the exception data for a sector, or NULL if not | |
576 | * remapped. | |
577 | */ | |
3510cb94 JB |
578 | static struct dm_exception *dm_lookup_exception(struct dm_exception_table *et, |
579 | chunk_t chunk) | |
1da177e4 LT |
580 | { |
581 | struct list_head *slot; | |
1d4989c8 | 582 | struct dm_exception *e; |
1da177e4 LT |
583 | |
584 | slot = &et->table[exception_hash(et, chunk)]; | |
585 | list_for_each_entry (e, slot, hash_list) | |
d74f81f8 MB |
586 | if (chunk >= e->old_chunk && |
587 | chunk <= e->old_chunk + dm_consecutive_chunk_count(e)) | |
1da177e4 LT |
588 | return e; |
589 | ||
590 | return NULL; | |
591 | } | |
592 | ||
3510cb94 | 593 | static struct dm_exception *alloc_completed_exception(void) |
1da177e4 | 594 | { |
1d4989c8 | 595 | struct dm_exception *e; |
1da177e4 LT |
596 | |
597 | e = kmem_cache_alloc(exception_cache, GFP_NOIO); | |
598 | if (!e) | |
599 | e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); | |
600 | ||
601 | return e; | |
602 | } | |
603 | ||
3510cb94 | 604 | static void free_completed_exception(struct dm_exception *e) |
1da177e4 LT |
605 | { |
606 | kmem_cache_free(exception_cache, e); | |
607 | } | |
608 | ||
92e86812 | 609 | static struct dm_snap_pending_exception *alloc_pending_exception(struct dm_snapshot *s) |
1da177e4 | 610 | { |
92e86812 MP |
611 | struct dm_snap_pending_exception *pe = mempool_alloc(s->pending_pool, |
612 | GFP_NOIO); | |
613 | ||
879129d2 | 614 | atomic_inc(&s->pending_exceptions_count); |
92e86812 MP |
615 | pe->snap = s; |
616 | ||
617 | return pe; | |
1da177e4 LT |
618 | } |
619 | ||
028867ac | 620 | static void free_pending_exception(struct dm_snap_pending_exception *pe) |
1da177e4 | 621 | { |
879129d2 MP |
622 | struct dm_snapshot *s = pe->snap; |
623 | ||
624 | mempool_free(pe, s->pending_pool); | |
625 | smp_mb__before_atomic_dec(); | |
626 | atomic_dec(&s->pending_exceptions_count); | |
1da177e4 LT |
627 | } |
628 | ||
3510cb94 JB |
629 | static void dm_insert_exception(struct dm_exception_table *eh, |
630 | struct dm_exception *new_e) | |
d74f81f8 | 631 | { |
d74f81f8 | 632 | struct list_head *l; |
1d4989c8 | 633 | struct dm_exception *e = NULL; |
d74f81f8 MB |
634 | |
635 | l = &eh->table[exception_hash(eh, new_e->old_chunk)]; | |
636 | ||
637 | /* Add immediately if this table doesn't support consecutive chunks */ | |
638 | if (!eh->hash_shift) | |
639 | goto out; | |
640 | ||
641 | /* List is ordered by old_chunk */ | |
642 | list_for_each_entry_reverse(e, l, hash_list) { | |
643 | /* Insert after an existing chunk? */ | |
644 | if (new_e->old_chunk == (e->old_chunk + | |
645 | dm_consecutive_chunk_count(e) + 1) && | |
646 | new_e->new_chunk == (dm_chunk_number(e->new_chunk) + | |
647 | dm_consecutive_chunk_count(e) + 1)) { | |
648 | dm_consecutive_chunk_count_inc(e); | |
3510cb94 | 649 | free_completed_exception(new_e); |
d74f81f8 MB |
650 | return; |
651 | } | |
652 | ||
653 | /* Insert before an existing chunk? */ | |
654 | if (new_e->old_chunk == (e->old_chunk - 1) && | |
655 | new_e->new_chunk == (dm_chunk_number(e->new_chunk) - 1)) { | |
656 | dm_consecutive_chunk_count_inc(e); | |
657 | e->old_chunk--; | |
658 | e->new_chunk--; | |
3510cb94 | 659 | free_completed_exception(new_e); |
d74f81f8 MB |
660 | return; |
661 | } | |
662 | ||
663 | if (new_e->old_chunk > e->old_chunk) | |
664 | break; | |
665 | } | |
666 | ||
667 | out: | |
668 | list_add(&new_e->hash_list, e ? &e->hash_list : l); | |
669 | } | |
670 | ||
a159c1ac JB |
671 | /* |
672 | * Callback used by the exception stores to load exceptions when | |
673 | * initialising. | |
674 | */ | |
675 | static int dm_add_exception(void *context, chunk_t old, chunk_t new) | |
1da177e4 | 676 | { |
a159c1ac | 677 | struct dm_snapshot *s = context; |
1d4989c8 | 678 | struct dm_exception *e; |
1da177e4 | 679 | |
3510cb94 | 680 | e = alloc_completed_exception(); |
1da177e4 LT |
681 | if (!e) |
682 | return -ENOMEM; | |
683 | ||
684 | e->old_chunk = old; | |
d74f81f8 MB |
685 | |
686 | /* Consecutive_count is implicitly initialised to zero */ | |
1da177e4 | 687 | e->new_chunk = new; |
d74f81f8 | 688 | |
3510cb94 | 689 | dm_insert_exception(&s->complete, e); |
d74f81f8 | 690 | |
1da177e4 LT |
691 | return 0; |
692 | } | |
693 | ||
7e201b35 MP |
694 | /* |
695 | * Return a minimum chunk size of all snapshots that have the specified origin. | |
696 | * Return zero if the origin has no snapshots. | |
697 | */ | |
542f9038 | 698 | static uint32_t __minimum_chunk_size(struct origin *o) |
7e201b35 MP |
699 | { |
700 | struct dm_snapshot *snap; | |
701 | unsigned chunk_size = 0; | |
702 | ||
703 | if (o) | |
704 | list_for_each_entry(snap, &o->snapshots, list) | |
705 | chunk_size = min_not_zero(chunk_size, | |
706 | snap->store->chunk_size); | |
707 | ||
542f9038 | 708 | return (uint32_t) chunk_size; |
7e201b35 MP |
709 | } |
710 | ||
1da177e4 LT |
711 | /* |
712 | * Hard coded magic. | |
713 | */ | |
714 | static int calc_max_buckets(void) | |
715 | { | |
716 | /* use a fixed size of 2MB */ | |
717 | unsigned long mem = 2 * 1024 * 1024; | |
718 | mem /= sizeof(struct list_head); | |
719 | ||
720 | return mem; | |
721 | } | |
722 | ||
1da177e4 LT |
723 | /* |
724 | * Allocate room for a suitable hash table. | |
725 | */ | |
fee1998e | 726 | static int init_hash_tables(struct dm_snapshot *s) |
1da177e4 LT |
727 | { |
728 | sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; | |
729 | ||
730 | /* | |
731 | * Calculate based on the size of the original volume or | |
732 | * the COW volume... | |
733 | */ | |
fc56f6fb | 734 | cow_dev_size = get_dev_size(s->cow->bdev); |
1da177e4 LT |
735 | origin_dev_size = get_dev_size(s->origin->bdev); |
736 | max_buckets = calc_max_buckets(); | |
737 | ||
fee1998e | 738 | hash_size = min(origin_dev_size, cow_dev_size) >> s->store->chunk_shift; |
1da177e4 LT |
739 | hash_size = min(hash_size, max_buckets); |
740 | ||
8e87b9b8 MP |
741 | if (hash_size < 64) |
742 | hash_size = 64; | |
8defd830 | 743 | hash_size = rounddown_pow_of_two(hash_size); |
3510cb94 JB |
744 | if (dm_exception_table_init(&s->complete, hash_size, |
745 | DM_CHUNK_CONSECUTIVE_BITS)) | |
1da177e4 LT |
746 | return -ENOMEM; |
747 | ||
748 | /* | |
749 | * Allocate hash table for in-flight exceptions | |
750 | * Make this smaller than the real hash table | |
751 | */ | |
752 | hash_size >>= 3; | |
753 | if (hash_size < 64) | |
754 | hash_size = 64; | |
755 | ||
3510cb94 JB |
756 | if (dm_exception_table_init(&s->pending, hash_size, 0)) { |
757 | dm_exception_table_exit(&s->complete, exception_cache); | |
1da177e4 LT |
758 | return -ENOMEM; |
759 | } | |
760 | ||
761 | return 0; | |
762 | } | |
763 | ||
1e03f97e MP |
764 | static void merge_shutdown(struct dm_snapshot *s) |
765 | { | |
766 | clear_bit_unlock(RUNNING_MERGE, &s->state_bits); | |
767 | smp_mb__after_clear_bit(); | |
768 | wake_up_bit(&s->state_bits, RUNNING_MERGE); | |
769 | } | |
770 | ||
9fe86254 MP |
771 | static struct bio *__release_queued_bios_after_merge(struct dm_snapshot *s) |
772 | { | |
773 | s->first_merging_chunk = 0; | |
774 | s->num_merging_chunks = 0; | |
775 | ||
776 | return bio_list_get(&s->bios_queued_during_merge); | |
777 | } | |
778 | ||
1e03f97e MP |
779 | /* |
780 | * Remove one chunk from the index of completed exceptions. | |
781 | */ | |
782 | static int __remove_single_exception_chunk(struct dm_snapshot *s, | |
783 | chunk_t old_chunk) | |
784 | { | |
785 | struct dm_exception *e; | |
786 | ||
1e03f97e MP |
787 | e = dm_lookup_exception(&s->complete, old_chunk); |
788 | if (!e) { | |
789 | DMERR("Corruption detected: exception for block %llu is " | |
790 | "on disk but not in memory", | |
791 | (unsigned long long)old_chunk); | |
792 | return -EINVAL; | |
793 | } | |
794 | ||
795 | /* | |
796 | * If this is the only chunk using this exception, remove exception. | |
797 | */ | |
798 | if (!dm_consecutive_chunk_count(e)) { | |
799 | dm_remove_exception(e); | |
800 | free_completed_exception(e); | |
801 | return 0; | |
802 | } | |
803 | ||
804 | /* | |
805 | * The chunk may be either at the beginning or the end of a | |
806 | * group of consecutive chunks - never in the middle. We are | |
807 | * removing chunks in the opposite order to that in which they | |
808 | * were added, so this should always be true. | |
809 | * Decrement the consecutive chunk counter and adjust the | |
810 | * starting point if necessary. | |
811 | */ | |
812 | if (old_chunk == e->old_chunk) { | |
813 | e->old_chunk++; | |
814 | e->new_chunk++; | |
815 | } else if (old_chunk != e->old_chunk + | |
816 | dm_consecutive_chunk_count(e)) { | |
817 | DMERR("Attempt to merge block %llu from the " | |
818 | "middle of a chunk range [%llu - %llu]", | |
819 | (unsigned long long)old_chunk, | |
820 | (unsigned long long)e->old_chunk, | |
821 | (unsigned long long) | |
822 | e->old_chunk + dm_consecutive_chunk_count(e)); | |
823 | return -EINVAL; | |
824 | } | |
825 | ||
826 | dm_consecutive_chunk_count_dec(e); | |
827 | ||
828 | return 0; | |
829 | } | |
830 | ||
9fe86254 MP |
831 | static void flush_bios(struct bio *bio); |
832 | ||
833 | static int remove_single_exception_chunk(struct dm_snapshot *s) | |
1e03f97e | 834 | { |
9fe86254 MP |
835 | struct bio *b = NULL; |
836 | int r; | |
837 | chunk_t old_chunk = s->first_merging_chunk + s->num_merging_chunks - 1; | |
1e03f97e MP |
838 | |
839 | down_write(&s->lock); | |
9fe86254 MP |
840 | |
841 | /* | |
842 | * Process chunks (and associated exceptions) in reverse order | |
843 | * so that dm_consecutive_chunk_count_dec() accounting works. | |
844 | */ | |
845 | do { | |
846 | r = __remove_single_exception_chunk(s, old_chunk); | |
847 | if (r) | |
848 | goto out; | |
849 | } while (old_chunk-- > s->first_merging_chunk); | |
850 | ||
851 | b = __release_queued_bios_after_merge(s); | |
852 | ||
853 | out: | |
1e03f97e | 854 | up_write(&s->lock); |
9fe86254 MP |
855 | if (b) |
856 | flush_bios(b); | |
1e03f97e MP |
857 | |
858 | return r; | |
859 | } | |
860 | ||
73dfd078 MP |
861 | static int origin_write_extent(struct dm_snapshot *merging_snap, |
862 | sector_t sector, unsigned chunk_size); | |
863 | ||
1e03f97e MP |
864 | static void merge_callback(int read_err, unsigned long write_err, |
865 | void *context); | |
866 | ||
73dfd078 MP |
867 | static uint64_t read_pending_exceptions_done_count(void) |
868 | { | |
869 | uint64_t pending_exceptions_done; | |
870 | ||
871 | spin_lock(&_pending_exceptions_done_spinlock); | |
872 | pending_exceptions_done = _pending_exceptions_done_count; | |
873 | spin_unlock(&_pending_exceptions_done_spinlock); | |
874 | ||
875 | return pending_exceptions_done; | |
876 | } | |
877 | ||
878 | static void increment_pending_exceptions_done_count(void) | |
879 | { | |
880 | spin_lock(&_pending_exceptions_done_spinlock); | |
881 | _pending_exceptions_done_count++; | |
882 | spin_unlock(&_pending_exceptions_done_spinlock); | |
883 | ||
884 | wake_up_all(&_pending_exceptions_done); | |
885 | } | |
886 | ||
1e03f97e MP |
887 | static void snapshot_merge_next_chunks(struct dm_snapshot *s) |
888 | { | |
8a2d5286 | 889 | int i, linear_chunks; |
1e03f97e MP |
890 | chunk_t old_chunk, new_chunk; |
891 | struct dm_io_region src, dest; | |
8a2d5286 | 892 | sector_t io_size; |
73dfd078 | 893 | uint64_t previous_count; |
1e03f97e MP |
894 | |
895 | BUG_ON(!test_bit(RUNNING_MERGE, &s->state_bits)); | |
896 | if (unlikely(test_bit(SHUTDOWN_MERGE, &s->state_bits))) | |
897 | goto shut; | |
898 | ||
899 | /* | |
900 | * valid flag never changes during merge, so no lock required. | |
901 | */ | |
902 | if (!s->valid) { | |
903 | DMERR("Snapshot is invalid: can't merge"); | |
904 | goto shut; | |
905 | } | |
906 | ||
8a2d5286 MS |
907 | linear_chunks = s->store->type->prepare_merge(s->store, &old_chunk, |
908 | &new_chunk); | |
909 | if (linear_chunks <= 0) { | |
d8ddb1cf | 910 | if (linear_chunks < 0) { |
1e03f97e MP |
911 | DMERR("Read error in exception store: " |
912 | "shutting down merge"); | |
d8ddb1cf MS |
913 | down_write(&s->lock); |
914 | s->merge_failed = 1; | |
915 | up_write(&s->lock); | |
916 | } | |
1e03f97e MP |
917 | goto shut; |
918 | } | |
919 | ||
8a2d5286 MS |
920 | /* Adjust old_chunk and new_chunk to reflect start of linear region */ |
921 | old_chunk = old_chunk + 1 - linear_chunks; | |
922 | new_chunk = new_chunk + 1 - linear_chunks; | |
923 | ||
924 | /* | |
925 | * Use one (potentially large) I/O to copy all 'linear_chunks' | |
926 | * from the exception store to the origin | |
927 | */ | |
928 | io_size = linear_chunks * s->store->chunk_size; | |
1e03f97e | 929 | |
1e03f97e MP |
930 | dest.bdev = s->origin->bdev; |
931 | dest.sector = chunk_to_sector(s->store, old_chunk); | |
8a2d5286 | 932 | dest.count = min(io_size, get_dev_size(dest.bdev) - dest.sector); |
1e03f97e MP |
933 | |
934 | src.bdev = s->cow->bdev; | |
935 | src.sector = chunk_to_sector(s->store, new_chunk); | |
936 | src.count = dest.count; | |
937 | ||
73dfd078 MP |
938 | /* |
939 | * Reallocate any exceptions needed in other snapshots then | |
940 | * wait for the pending exceptions to complete. | |
941 | * Each time any pending exception (globally on the system) | |
942 | * completes we are woken and repeat the process to find out | |
943 | * if we can proceed. While this may not seem a particularly | |
944 | * efficient algorithm, it is not expected to have any | |
945 | * significant impact on performance. | |
946 | */ | |
947 | previous_count = read_pending_exceptions_done_count(); | |
8a2d5286 | 948 | while (origin_write_extent(s, dest.sector, io_size)) { |
73dfd078 MP |
949 | wait_event(_pending_exceptions_done, |
950 | (read_pending_exceptions_done_count() != | |
951 | previous_count)); | |
952 | /* Retry after the wait, until all exceptions are done. */ | |
953 | previous_count = read_pending_exceptions_done_count(); | |
954 | } | |
955 | ||
9fe86254 MP |
956 | down_write(&s->lock); |
957 | s->first_merging_chunk = old_chunk; | |
8a2d5286 | 958 | s->num_merging_chunks = linear_chunks; |
9fe86254 MP |
959 | up_write(&s->lock); |
960 | ||
8a2d5286 MS |
961 | /* Wait until writes to all 'linear_chunks' drain */ |
962 | for (i = 0; i < linear_chunks; i++) | |
963 | __check_for_conflicting_io(s, old_chunk + i); | |
9fe86254 | 964 | |
1e03f97e MP |
965 | dm_kcopyd_copy(s->kcopyd_client, &src, 1, &dest, 0, merge_callback, s); |
966 | return; | |
967 | ||
968 | shut: | |
969 | merge_shutdown(s); | |
970 | } | |
971 | ||
9fe86254 MP |
972 | static void error_bios(struct bio *bio); |
973 | ||
1e03f97e MP |
974 | static void merge_callback(int read_err, unsigned long write_err, void *context) |
975 | { | |
976 | struct dm_snapshot *s = context; | |
9fe86254 | 977 | struct bio *b = NULL; |
1e03f97e MP |
978 | |
979 | if (read_err || write_err) { | |
980 | if (read_err) | |
981 | DMERR("Read error: shutting down merge."); | |
982 | else | |
983 | DMERR("Write error: shutting down merge."); | |
984 | goto shut; | |
985 | } | |
986 | ||
9fe86254 MP |
987 | if (s->store->type->commit_merge(s->store, |
988 | s->num_merging_chunks) < 0) { | |
1e03f97e MP |
989 | DMERR("Write error in exception store: shutting down merge"); |
990 | goto shut; | |
991 | } | |
992 | ||
9fe86254 MP |
993 | if (remove_single_exception_chunk(s) < 0) |
994 | goto shut; | |
995 | ||
1e03f97e MP |
996 | snapshot_merge_next_chunks(s); |
997 | ||
998 | return; | |
999 | ||
1000 | shut: | |
9fe86254 | 1001 | down_write(&s->lock); |
d8ddb1cf | 1002 | s->merge_failed = 1; |
9fe86254 MP |
1003 | b = __release_queued_bios_after_merge(s); |
1004 | up_write(&s->lock); | |
1005 | error_bios(b); | |
1006 | ||
1e03f97e MP |
1007 | merge_shutdown(s); |
1008 | } | |
1009 | ||
1010 | static void start_merge(struct dm_snapshot *s) | |
1011 | { | |
1012 | if (!test_and_set_bit(RUNNING_MERGE, &s->state_bits)) | |
1013 | snapshot_merge_next_chunks(s); | |
1014 | } | |
1015 | ||
1016 | static int wait_schedule(void *ptr) | |
1017 | { | |
1018 | schedule(); | |
1019 | ||
1020 | return 0; | |
1021 | } | |
1022 | ||
1023 | /* | |
1024 | * Stop the merging process and wait until it finishes. | |
1025 | */ | |
1026 | static void stop_merge(struct dm_snapshot *s) | |
1027 | { | |
1028 | set_bit(SHUTDOWN_MERGE, &s->state_bits); | |
1029 | wait_on_bit(&s->state_bits, RUNNING_MERGE, wait_schedule, | |
1030 | TASK_UNINTERRUPTIBLE); | |
1031 | clear_bit(SHUTDOWN_MERGE, &s->state_bits); | |
1032 | } | |
1033 | ||
1da177e4 LT |
1034 | /* |
1035 | * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> | |
1036 | */ | |
1037 | static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
1038 | { | |
1039 | struct dm_snapshot *s; | |
cd45daff | 1040 | int i; |
1da177e4 | 1041 | int r = -EINVAL; |
fc56f6fb | 1042 | char *origin_path, *cow_path; |
55a62eef | 1043 | unsigned args_used, num_flush_bios = 1; |
10b8106a | 1044 | fmode_t origin_mode = FMODE_READ; |
1da177e4 | 1045 | |
4c7e3bf4 | 1046 | if (argc != 4) { |
72d94861 | 1047 | ti->error = "requires exactly 4 arguments"; |
1da177e4 | 1048 | r = -EINVAL; |
fc56f6fb | 1049 | goto bad; |
1da177e4 LT |
1050 | } |
1051 | ||
10b8106a | 1052 | if (dm_target_is_snapshot_merge(ti)) { |
55a62eef | 1053 | num_flush_bios = 2; |
10b8106a MS |
1054 | origin_mode = FMODE_WRITE; |
1055 | } | |
1056 | ||
fc56f6fb MS |
1057 | s = kmalloc(sizeof(*s), GFP_KERNEL); |
1058 | if (!s) { | |
a2d2b034 | 1059 | ti->error = "Cannot allocate private snapshot structure"; |
fc56f6fb MS |
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 | ||
df5d2e90 | 1114 | s->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle); |
fa34ce73 MP |
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 | for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) |
1128 | INIT_HLIST_HEAD(&s->tracked_chunk_hash[i]); | |
1129 | ||
1130 | spin_lock_init(&s->tracked_chunk_lock); | |
1131 | ||
c1f0c183 | 1132 | ti->private = s; |
55a62eef | 1133 | ti->num_flush_bios = num_flush_bios; |
42bc954f | 1134 | ti->per_bio_data_size = sizeof(struct dm_snap_tracked_chunk); |
c1f0c183 MS |
1135 | |
1136 | /* Add snapshot to the list of snapshots for this origin */ | |
1137 | /* Exceptions aren't triggered till snapshot_resume() is called */ | |
1138 | r = register_snapshot(s); | |
1139 | if (r == -ENOMEM) { | |
1140 | ti->error = "Snapshot origin struct allocation failed"; | |
1141 | goto bad_load_and_register; | |
1142 | } else if (r < 0) { | |
1143 | /* invalid handover, register_snapshot has set ti->error */ | |
1144 | goto bad_load_and_register; | |
1145 | } | |
1146 | ||
1147 | /* | |
1148 | * Metadata must only be loaded into one table at once, so skip this | |
1149 | * if metadata will be handed over during resume. | |
1150 | * Chunk size will be set during the handover - set it to zero to | |
1151 | * ensure it's ignored. | |
1152 | */ | |
1153 | if (r > 0) { | |
1154 | s->store->chunk_size = 0; | |
1155 | return 0; | |
1156 | } | |
1157 | ||
493df71c JB |
1158 | r = s->store->type->read_metadata(s->store, dm_add_exception, |
1159 | (void *)s); | |
0764147b | 1160 | if (r < 0) { |
f9cea4f7 | 1161 | ti->error = "Failed to read snapshot metadata"; |
c1f0c183 | 1162 | goto bad_read_metadata; |
0764147b MB |
1163 | } else if (r > 0) { |
1164 | s->valid = 0; | |
1165 | DMWARN("Snapshot is marked invalid."); | |
f9cea4f7 | 1166 | } |
aa14edeb | 1167 | |
3f2412dc MP |
1168 | if (!s->store->chunk_size) { |
1169 | ti->error = "Chunk size not set"; | |
c1f0c183 | 1170 | goto bad_read_metadata; |
1da177e4 | 1171 | } |
542f9038 MS |
1172 | |
1173 | r = dm_set_target_max_io_len(ti, s->store->chunk_size); | |
1174 | if (r) | |
1175 | goto bad_read_metadata; | |
1da177e4 LT |
1176 | |
1177 | return 0; | |
1178 | ||
c1f0c183 MS |
1179 | bad_read_metadata: |
1180 | unregister_snapshot(s); | |
1181 | ||
fee1998e | 1182 | bad_load_and_register: |
92e86812 MP |
1183 | mempool_destroy(s->pending_pool); |
1184 | ||
fee1998e | 1185 | bad_pending_pool: |
eb69aca5 | 1186 | dm_kcopyd_client_destroy(s->kcopyd_client); |
1da177e4 | 1187 | |
fee1998e | 1188 | bad_kcopyd: |
3510cb94 JB |
1189 | dm_exception_table_exit(&s->pending, pending_cache); |
1190 | dm_exception_table_exit(&s->complete, exception_cache); | |
1da177e4 | 1191 | |
fee1998e | 1192 | bad_hash_tables: |
fc56f6fb | 1193 | dm_exception_store_destroy(s->store); |
1da177e4 | 1194 | |
fc56f6fb MS |
1195 | bad_store: |
1196 | dm_put_device(ti, s->cow); | |
fee1998e | 1197 | |
fc56f6fb | 1198 | bad_cow: |
c2411045 MP |
1199 | dm_put_device(ti, s->origin); |
1200 | ||
1201 | bad_origin: | |
fc56f6fb MS |
1202 | kfree(s); |
1203 | ||
1204 | bad: | |
1da177e4 LT |
1205 | return r; |
1206 | } | |
1207 | ||
31c93a0c MB |
1208 | static void __free_exceptions(struct dm_snapshot *s) |
1209 | { | |
eb69aca5 | 1210 | dm_kcopyd_client_destroy(s->kcopyd_client); |
31c93a0c MB |
1211 | s->kcopyd_client = NULL; |
1212 | ||
3510cb94 JB |
1213 | dm_exception_table_exit(&s->pending, pending_cache); |
1214 | dm_exception_table_exit(&s->complete, exception_cache); | |
31c93a0c MB |
1215 | } |
1216 | ||
c1f0c183 MS |
1217 | static void __handover_exceptions(struct dm_snapshot *snap_src, |
1218 | struct dm_snapshot *snap_dest) | |
1219 | { | |
1220 | union { | |
1221 | struct dm_exception_table table_swap; | |
1222 | struct dm_exception_store *store_swap; | |
1223 | } u; | |
1224 | ||
1225 | /* | |
1226 | * Swap all snapshot context information between the two instances. | |
1227 | */ | |
1228 | u.table_swap = snap_dest->complete; | |
1229 | snap_dest->complete = snap_src->complete; | |
1230 | snap_src->complete = u.table_swap; | |
1231 | ||
1232 | u.store_swap = snap_dest->store; | |
1233 | snap_dest->store = snap_src->store; | |
1234 | snap_src->store = u.store_swap; | |
1235 | ||
1236 | snap_dest->store->snap = snap_dest; | |
1237 | snap_src->store->snap = snap_src; | |
1238 | ||
542f9038 | 1239 | snap_dest->ti->max_io_len = snap_dest->store->chunk_size; |
c1f0c183 MS |
1240 | snap_dest->valid = snap_src->valid; |
1241 | ||
1242 | /* | |
1243 | * Set source invalid to ensure it receives no further I/O. | |
1244 | */ | |
1245 | snap_src->valid = 0; | |
1246 | } | |
1247 | ||
1da177e4 LT |
1248 | static void snapshot_dtr(struct dm_target *ti) |
1249 | { | |
cd45daff MP |
1250 | #ifdef CONFIG_DM_DEBUG |
1251 | int i; | |
1252 | #endif | |
028867ac | 1253 | struct dm_snapshot *s = ti->private; |
c1f0c183 | 1254 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; |
1da177e4 | 1255 | |
c1f0c183 MS |
1256 | down_read(&_origins_lock); |
1257 | /* Check whether exception handover must be cancelled */ | |
9d3b15c4 | 1258 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1259 | if (snap_src && snap_dest && (s == snap_src)) { |
1260 | down_write(&snap_dest->lock); | |
1261 | snap_dest->valid = 0; | |
1262 | up_write(&snap_dest->lock); | |
1263 | DMERR("Cancelling snapshot handover."); | |
1264 | } | |
1265 | up_read(&_origins_lock); | |
1266 | ||
1e03f97e MP |
1267 | if (dm_target_is_snapshot_merge(ti)) |
1268 | stop_merge(s); | |
1269 | ||
138728dc AK |
1270 | /* Prevent further origin writes from using this snapshot. */ |
1271 | /* After this returns there can be no new kcopyd jobs. */ | |
1da177e4 LT |
1272 | unregister_snapshot(s); |
1273 | ||
879129d2 | 1274 | while (atomic_read(&s->pending_exceptions_count)) |
90fa1527 | 1275 | msleep(1); |
879129d2 MP |
1276 | /* |
1277 | * Ensure instructions in mempool_destroy aren't reordered | |
1278 | * before atomic_read. | |
1279 | */ | |
1280 | smp_mb(); | |
1281 | ||
cd45daff MP |
1282 | #ifdef CONFIG_DM_DEBUG |
1283 | for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) | |
1284 | BUG_ON(!hlist_empty(&s->tracked_chunk_hash[i])); | |
1285 | #endif | |
1286 | ||
31c93a0c | 1287 | __free_exceptions(s); |
1da177e4 | 1288 | |
92e86812 MP |
1289 | mempool_destroy(s->pending_pool); |
1290 | ||
fee1998e | 1291 | dm_exception_store_destroy(s->store); |
138728dc | 1292 | |
fc56f6fb MS |
1293 | dm_put_device(ti, s->cow); |
1294 | ||
c2411045 MP |
1295 | dm_put_device(ti, s->origin); |
1296 | ||
1da177e4 LT |
1297 | kfree(s); |
1298 | } | |
1299 | ||
1300 | /* | |
1301 | * Flush a list of buffers. | |
1302 | */ | |
1303 | static void flush_bios(struct bio *bio) | |
1304 | { | |
1305 | struct bio *n; | |
1306 | ||
1307 | while (bio) { | |
1308 | n = bio->bi_next; | |
1309 | bio->bi_next = NULL; | |
1310 | generic_make_request(bio); | |
1311 | bio = n; | |
1312 | } | |
1313 | } | |
1314 | ||
515ad66c MP |
1315 | static int do_origin(struct dm_dev *origin, struct bio *bio); |
1316 | ||
1317 | /* | |
1318 | * Flush a list of buffers. | |
1319 | */ | |
1320 | static void retry_origin_bios(struct dm_snapshot *s, struct bio *bio) | |
1321 | { | |
1322 | struct bio *n; | |
1323 | int r; | |
1324 | ||
1325 | while (bio) { | |
1326 | n = bio->bi_next; | |
1327 | bio->bi_next = NULL; | |
1328 | r = do_origin(s->origin, bio); | |
1329 | if (r == DM_MAPIO_REMAPPED) | |
1330 | generic_make_request(bio); | |
1331 | bio = n; | |
1332 | } | |
1333 | } | |
1334 | ||
1da177e4 LT |
1335 | /* |
1336 | * Error a list of buffers. | |
1337 | */ | |
1338 | static void error_bios(struct bio *bio) | |
1339 | { | |
1340 | struct bio *n; | |
1341 | ||
1342 | while (bio) { | |
1343 | n = bio->bi_next; | |
1344 | bio->bi_next = NULL; | |
6712ecf8 | 1345 | bio_io_error(bio); |
1da177e4 LT |
1346 | bio = n; |
1347 | } | |
1348 | } | |
1349 | ||
695368ac | 1350 | static void __invalidate_snapshot(struct dm_snapshot *s, int err) |
76df1c65 AK |
1351 | { |
1352 | if (!s->valid) | |
1353 | return; | |
1354 | ||
1355 | if (err == -EIO) | |
1356 | DMERR("Invalidating snapshot: Error reading/writing."); | |
1357 | else if (err == -ENOMEM) | |
1358 | DMERR("Invalidating snapshot: Unable to allocate exception."); | |
1359 | ||
493df71c JB |
1360 | if (s->store->type->drop_snapshot) |
1361 | s->store->type->drop_snapshot(s->store); | |
76df1c65 AK |
1362 | |
1363 | s->valid = 0; | |
1364 | ||
fc56f6fb | 1365 | dm_table_event(s->ti->table); |
76df1c65 AK |
1366 | } |
1367 | ||
028867ac | 1368 | static void pending_complete(struct dm_snap_pending_exception *pe, int success) |
1da177e4 | 1369 | { |
1d4989c8 | 1370 | struct dm_exception *e; |
1da177e4 | 1371 | struct dm_snapshot *s = pe->snap; |
9d493fa8 AK |
1372 | struct bio *origin_bios = NULL; |
1373 | struct bio *snapshot_bios = NULL; | |
a6e50b40 | 1374 | struct bio *full_bio = NULL; |
9d493fa8 | 1375 | int error = 0; |
1da177e4 | 1376 | |
76df1c65 AK |
1377 | if (!success) { |
1378 | /* Read/write error - snapshot is unusable */ | |
1da177e4 | 1379 | down_write(&s->lock); |
695368ac | 1380 | __invalidate_snapshot(s, -EIO); |
9d493fa8 | 1381 | error = 1; |
76df1c65 AK |
1382 | goto out; |
1383 | } | |
1384 | ||
3510cb94 | 1385 | e = alloc_completed_exception(); |
76df1c65 | 1386 | if (!e) { |
1da177e4 | 1387 | down_write(&s->lock); |
695368ac | 1388 | __invalidate_snapshot(s, -ENOMEM); |
9d493fa8 | 1389 | error = 1; |
76df1c65 AK |
1390 | goto out; |
1391 | } | |
1392 | *e = pe->e; | |
1da177e4 | 1393 | |
76df1c65 AK |
1394 | down_write(&s->lock); |
1395 | if (!s->valid) { | |
3510cb94 | 1396 | free_completed_exception(e); |
9d493fa8 | 1397 | error = 1; |
76df1c65 | 1398 | goto out; |
1da177e4 LT |
1399 | } |
1400 | ||
615d1eb9 MS |
1401 | /* Check for conflicting reads */ |
1402 | __check_for_conflicting_io(s, pe->e.old_chunk); | |
a8d41b59 | 1403 | |
9d493fa8 AK |
1404 | /* |
1405 | * Add a proper exception, and remove the | |
1406 | * in-flight exception from the list. | |
1407 | */ | |
3510cb94 | 1408 | dm_insert_exception(&s->complete, e); |
76df1c65 | 1409 | |
a2d2b034 | 1410 | out: |
3510cb94 | 1411 | dm_remove_exception(&pe->e); |
9d493fa8 | 1412 | snapshot_bios = bio_list_get(&pe->snapshot_bios); |
515ad66c | 1413 | origin_bios = bio_list_get(&pe->origin_bios); |
a6e50b40 MP |
1414 | full_bio = pe->full_bio; |
1415 | if (full_bio) { | |
1416 | full_bio->bi_end_io = pe->full_bio_end_io; | |
1417 | full_bio->bi_private = pe->full_bio_private; | |
1418 | } | |
515ad66c | 1419 | free_pending_exception(pe); |
1da177e4 | 1420 | |
73dfd078 MP |
1421 | increment_pending_exceptions_done_count(); |
1422 | ||
9d493fa8 AK |
1423 | up_write(&s->lock); |
1424 | ||
1425 | /* Submit any pending write bios */ | |
a6e50b40 MP |
1426 | if (error) { |
1427 | if (full_bio) | |
1428 | bio_io_error(full_bio); | |
9d493fa8 | 1429 | error_bios(snapshot_bios); |
a6e50b40 MP |
1430 | } else { |
1431 | if (full_bio) | |
1432 | bio_endio(full_bio, 0); | |
9d493fa8 | 1433 | flush_bios(snapshot_bios); |
a6e50b40 | 1434 | } |
9d493fa8 | 1435 | |
515ad66c | 1436 | retry_origin_bios(s, origin_bios); |
1da177e4 LT |
1437 | } |
1438 | ||
1439 | static void commit_callback(void *context, int success) | |
1440 | { | |
028867ac AK |
1441 | struct dm_snap_pending_exception *pe = context; |
1442 | ||
1da177e4 LT |
1443 | pending_complete(pe, success); |
1444 | } | |
1445 | ||
1446 | /* | |
1447 | * Called when the copy I/O has finished. kcopyd actually runs | |
1448 | * this code so don't block. | |
1449 | */ | |
4cdc1d1f | 1450 | static void copy_callback(int read_err, unsigned long write_err, void *context) |
1da177e4 | 1451 | { |
028867ac | 1452 | struct dm_snap_pending_exception *pe = context; |
1da177e4 LT |
1453 | struct dm_snapshot *s = pe->snap; |
1454 | ||
1455 | if (read_err || write_err) | |
1456 | pending_complete(pe, 0); | |
1457 | ||
1458 | else | |
1459 | /* Update the metadata if we are persistent */ | |
493df71c JB |
1460 | s->store->type->commit_exception(s->store, &pe->e, |
1461 | commit_callback, pe); | |
1da177e4 LT |
1462 | } |
1463 | ||
1464 | /* | |
1465 | * Dispatches the copy operation to kcopyd. | |
1466 | */ | |
028867ac | 1467 | static void start_copy(struct dm_snap_pending_exception *pe) |
1da177e4 LT |
1468 | { |
1469 | struct dm_snapshot *s = pe->snap; | |
22a1ceb1 | 1470 | struct dm_io_region src, dest; |
1da177e4 LT |
1471 | struct block_device *bdev = s->origin->bdev; |
1472 | sector_t dev_size; | |
1473 | ||
1474 | dev_size = get_dev_size(bdev); | |
1475 | ||
1476 | src.bdev = bdev; | |
71fab00a | 1477 | src.sector = chunk_to_sector(s->store, pe->e.old_chunk); |
df96eee6 | 1478 | src.count = min((sector_t)s->store->chunk_size, dev_size - src.sector); |
1da177e4 | 1479 | |
fc56f6fb | 1480 | dest.bdev = s->cow->bdev; |
71fab00a | 1481 | dest.sector = chunk_to_sector(s->store, pe->e.new_chunk); |
1da177e4 LT |
1482 | dest.count = src.count; |
1483 | ||
1484 | /* Hand over to kcopyd */ | |
a2d2b034 | 1485 | dm_kcopyd_copy(s->kcopyd_client, &src, 1, &dest, 0, copy_callback, pe); |
1da177e4 LT |
1486 | } |
1487 | ||
a6e50b40 MP |
1488 | static void full_bio_end_io(struct bio *bio, int error) |
1489 | { | |
1490 | void *callback_data = bio->bi_private; | |
1491 | ||
1492 | dm_kcopyd_do_callback(callback_data, 0, error ? 1 : 0); | |
1493 | } | |
1494 | ||
1495 | static void start_full_bio(struct dm_snap_pending_exception *pe, | |
1496 | struct bio *bio) | |
1497 | { | |
1498 | struct dm_snapshot *s = pe->snap; | |
1499 | void *callback_data; | |
1500 | ||
1501 | pe->full_bio = bio; | |
1502 | pe->full_bio_end_io = bio->bi_end_io; | |
1503 | pe->full_bio_private = bio->bi_private; | |
1504 | ||
1505 | callback_data = dm_kcopyd_prepare_callback(s->kcopyd_client, | |
1506 | copy_callback, pe); | |
1507 | ||
1508 | bio->bi_end_io = full_bio_end_io; | |
1509 | bio->bi_private = callback_data; | |
1510 | ||
1511 | generic_make_request(bio); | |
1512 | } | |
1513 | ||
2913808e MP |
1514 | static struct dm_snap_pending_exception * |
1515 | __lookup_pending_exception(struct dm_snapshot *s, chunk_t chunk) | |
1516 | { | |
3510cb94 | 1517 | struct dm_exception *e = dm_lookup_exception(&s->pending, chunk); |
2913808e MP |
1518 | |
1519 | if (!e) | |
1520 | return NULL; | |
1521 | ||
1522 | return container_of(e, struct dm_snap_pending_exception, e); | |
1523 | } | |
1524 | ||
1da177e4 LT |
1525 | /* |
1526 | * Looks to see if this snapshot already has a pending exception | |
1527 | * for this chunk, otherwise it allocates a new one and inserts | |
1528 | * it into the pending table. | |
1529 | * | |
1530 | * NOTE: a write lock must be held on snap->lock before calling | |
1531 | * this. | |
1532 | */ | |
028867ac | 1533 | static struct dm_snap_pending_exception * |
c6621392 MP |
1534 | __find_pending_exception(struct dm_snapshot *s, |
1535 | struct dm_snap_pending_exception *pe, chunk_t chunk) | |
1da177e4 | 1536 | { |
c6621392 | 1537 | struct dm_snap_pending_exception *pe2; |
1da177e4 | 1538 | |
2913808e MP |
1539 | pe2 = __lookup_pending_exception(s, chunk); |
1540 | if (pe2) { | |
76df1c65 | 1541 | free_pending_exception(pe); |
2913808e | 1542 | return pe2; |
1da177e4 LT |
1543 | } |
1544 | ||
76df1c65 AK |
1545 | pe->e.old_chunk = chunk; |
1546 | bio_list_init(&pe->origin_bios); | |
1547 | bio_list_init(&pe->snapshot_bios); | |
76df1c65 | 1548 | pe->started = 0; |
a6e50b40 | 1549 | pe->full_bio = NULL; |
76df1c65 | 1550 | |
493df71c | 1551 | if (s->store->type->prepare_exception(s->store, &pe->e)) { |
76df1c65 AK |
1552 | free_pending_exception(pe); |
1553 | return NULL; | |
1554 | } | |
1555 | ||
3510cb94 | 1556 | dm_insert_exception(&s->pending, &pe->e); |
76df1c65 | 1557 | |
1da177e4 LT |
1558 | return pe; |
1559 | } | |
1560 | ||
1d4989c8 | 1561 | static void remap_exception(struct dm_snapshot *s, struct dm_exception *e, |
d74f81f8 | 1562 | struct bio *bio, chunk_t chunk) |
1da177e4 | 1563 | { |
fc56f6fb | 1564 | bio->bi_bdev = s->cow->bdev; |
71fab00a JB |
1565 | bio->bi_sector = chunk_to_sector(s->store, |
1566 | dm_chunk_number(e->new_chunk) + | |
1567 | (chunk - e->old_chunk)) + | |
1568 | (bio->bi_sector & | |
1569 | s->store->chunk_mask); | |
1da177e4 LT |
1570 | } |
1571 | ||
7de3ee57 | 1572 | static int snapshot_map(struct dm_target *ti, struct bio *bio) |
1da177e4 | 1573 | { |
1d4989c8 | 1574 | struct dm_exception *e; |
028867ac | 1575 | struct dm_snapshot *s = ti->private; |
d2a7ad29 | 1576 | int r = DM_MAPIO_REMAPPED; |
1da177e4 | 1577 | chunk_t chunk; |
028867ac | 1578 | struct dm_snap_pending_exception *pe = NULL; |
1da177e4 | 1579 | |
ee18026a MP |
1580 | init_tracked_chunk(bio); |
1581 | ||
d87f4c14 | 1582 | if (bio->bi_rw & REQ_FLUSH) { |
fc56f6fb | 1583 | bio->bi_bdev = s->cow->bdev; |
494b3ee7 MP |
1584 | return DM_MAPIO_REMAPPED; |
1585 | } | |
1586 | ||
71fab00a | 1587 | chunk = sector_to_chunk(s->store, bio->bi_sector); |
1da177e4 LT |
1588 | |
1589 | /* Full snapshots are not usable */ | |
76df1c65 | 1590 | /* To get here the table must be live so s->active is always set. */ |
1da177e4 | 1591 | if (!s->valid) |
f6a80ea8 | 1592 | return -EIO; |
1da177e4 | 1593 | |
ba40a2aa AK |
1594 | /* FIXME: should only take write lock if we need |
1595 | * to copy an exception */ | |
1596 | down_write(&s->lock); | |
1597 | ||
1598 | if (!s->valid) { | |
1599 | r = -EIO; | |
1600 | goto out_unlock; | |
1601 | } | |
1602 | ||
1603 | /* If the block is already remapped - use that, else remap it */ | |
3510cb94 | 1604 | e = dm_lookup_exception(&s->complete, chunk); |
ba40a2aa | 1605 | if (e) { |
d74f81f8 | 1606 | remap_exception(s, e, bio, chunk); |
ba40a2aa AK |
1607 | goto out_unlock; |
1608 | } | |
1609 | ||
1da177e4 LT |
1610 | /* |
1611 | * Write to snapshot - higher level takes care of RW/RO | |
1612 | * flags so we should only get this if we are | |
1613 | * writeable. | |
1614 | */ | |
1615 | if (bio_rw(bio) == WRITE) { | |
2913808e | 1616 | pe = __lookup_pending_exception(s, chunk); |
76df1c65 | 1617 | if (!pe) { |
c6621392 MP |
1618 | up_write(&s->lock); |
1619 | pe = alloc_pending_exception(s); | |
1620 | down_write(&s->lock); | |
1621 | ||
1622 | if (!s->valid) { | |
1623 | free_pending_exception(pe); | |
1624 | r = -EIO; | |
1625 | goto out_unlock; | |
1626 | } | |
1627 | ||
3510cb94 | 1628 | e = dm_lookup_exception(&s->complete, chunk); |
35bf659b MP |
1629 | if (e) { |
1630 | free_pending_exception(pe); | |
1631 | remap_exception(s, e, bio, chunk); | |
1632 | goto out_unlock; | |
1633 | } | |
1634 | ||
c6621392 | 1635 | pe = __find_pending_exception(s, pe, chunk); |
2913808e MP |
1636 | if (!pe) { |
1637 | __invalidate_snapshot(s, -ENOMEM); | |
1638 | r = -EIO; | |
1639 | goto out_unlock; | |
1640 | } | |
1da177e4 LT |
1641 | } |
1642 | ||
d74f81f8 | 1643 | remap_exception(s, &pe->e, bio, chunk); |
76df1c65 | 1644 | |
d2a7ad29 | 1645 | r = DM_MAPIO_SUBMITTED; |
ba40a2aa | 1646 | |
a6e50b40 MP |
1647 | if (!pe->started && |
1648 | bio->bi_size == (s->store->chunk_size << SECTOR_SHIFT)) { | |
1649 | pe->started = 1; | |
1650 | up_write(&s->lock); | |
1651 | start_full_bio(pe, bio); | |
1652 | goto out; | |
1653 | } | |
1654 | ||
1655 | bio_list_add(&pe->snapshot_bios, bio); | |
1656 | ||
76df1c65 AK |
1657 | if (!pe->started) { |
1658 | /* this is protected by snap->lock */ | |
1659 | pe->started = 1; | |
ba40a2aa | 1660 | up_write(&s->lock); |
76df1c65 | 1661 | start_copy(pe); |
ba40a2aa AK |
1662 | goto out; |
1663 | } | |
cd45daff | 1664 | } else { |
ba40a2aa | 1665 | bio->bi_bdev = s->origin->bdev; |
ee18026a | 1666 | track_chunk(s, bio, chunk); |
cd45daff | 1667 | } |
1da177e4 | 1668 | |
a2d2b034 | 1669 | out_unlock: |
ba40a2aa | 1670 | up_write(&s->lock); |
a2d2b034 | 1671 | out: |
1da177e4 LT |
1672 | return r; |
1673 | } | |
1674 | ||
3452c2a1 MP |
1675 | /* |
1676 | * A snapshot-merge target behaves like a combination of a snapshot | |
1677 | * target and a snapshot-origin target. It only generates new | |
1678 | * exceptions in other snapshots and not in the one that is being | |
1679 | * merged. | |
1680 | * | |
1681 | * For each chunk, if there is an existing exception, it is used to | |
1682 | * redirect I/O to the cow device. Otherwise I/O is sent to the origin, | |
1683 | * which in turn might generate exceptions in other snapshots. | |
9fe86254 MP |
1684 | * If merging is currently taking place on the chunk in question, the |
1685 | * I/O is deferred by adding it to s->bios_queued_during_merge. | |
3452c2a1 | 1686 | */ |
7de3ee57 | 1687 | static int snapshot_merge_map(struct dm_target *ti, struct bio *bio) |
3452c2a1 MP |
1688 | { |
1689 | struct dm_exception *e; | |
1690 | struct dm_snapshot *s = ti->private; | |
1691 | int r = DM_MAPIO_REMAPPED; | |
1692 | chunk_t chunk; | |
1693 | ||
ee18026a MP |
1694 | init_tracked_chunk(bio); |
1695 | ||
d87f4c14 | 1696 | if (bio->bi_rw & REQ_FLUSH) { |
55a62eef | 1697 | if (!dm_bio_get_target_bio_nr(bio)) |
10b8106a MS |
1698 | bio->bi_bdev = s->origin->bdev; |
1699 | else | |
1700 | bio->bi_bdev = s->cow->bdev; | |
10b8106a MS |
1701 | return DM_MAPIO_REMAPPED; |
1702 | } | |
1703 | ||
3452c2a1 MP |
1704 | chunk = sector_to_chunk(s->store, bio->bi_sector); |
1705 | ||
9fe86254 | 1706 | down_write(&s->lock); |
3452c2a1 | 1707 | |
d2fdb776 MP |
1708 | /* Full merging snapshots are redirected to the origin */ |
1709 | if (!s->valid) | |
1710 | goto redirect_to_origin; | |
3452c2a1 MP |
1711 | |
1712 | /* If the block is already remapped - use that */ | |
1713 | e = dm_lookup_exception(&s->complete, chunk); | |
1714 | if (e) { | |
9fe86254 MP |
1715 | /* Queue writes overlapping with chunks being merged */ |
1716 | if (bio_rw(bio) == WRITE && | |
1717 | chunk >= s->first_merging_chunk && | |
1718 | chunk < (s->first_merging_chunk + | |
1719 | s->num_merging_chunks)) { | |
1720 | bio->bi_bdev = s->origin->bdev; | |
1721 | bio_list_add(&s->bios_queued_during_merge, bio); | |
1722 | r = DM_MAPIO_SUBMITTED; | |
1723 | goto out_unlock; | |
1724 | } | |
17aa0332 | 1725 | |
3452c2a1 | 1726 | remap_exception(s, e, bio, chunk); |
17aa0332 MP |
1727 | |
1728 | if (bio_rw(bio) == WRITE) | |
ee18026a | 1729 | track_chunk(s, bio, chunk); |
3452c2a1 MP |
1730 | goto out_unlock; |
1731 | } | |
1732 | ||
d2fdb776 | 1733 | redirect_to_origin: |
3452c2a1 MP |
1734 | bio->bi_bdev = s->origin->bdev; |
1735 | ||
1736 | if (bio_rw(bio) == WRITE) { | |
9fe86254 | 1737 | up_write(&s->lock); |
3452c2a1 MP |
1738 | return do_origin(s->origin, bio); |
1739 | } | |
1740 | ||
1741 | out_unlock: | |
9fe86254 | 1742 | up_write(&s->lock); |
3452c2a1 MP |
1743 | |
1744 | return r; | |
1745 | } | |
1746 | ||
7de3ee57 | 1747 | static int snapshot_end_io(struct dm_target *ti, struct bio *bio, int error) |
cd45daff MP |
1748 | { |
1749 | struct dm_snapshot *s = ti->private; | |
cd45daff | 1750 | |
ee18026a MP |
1751 | if (is_bio_tracked(bio)) |
1752 | stop_tracking_chunk(s, bio); | |
cd45daff MP |
1753 | |
1754 | return 0; | |
1755 | } | |
1756 | ||
1e03f97e MP |
1757 | static void snapshot_merge_presuspend(struct dm_target *ti) |
1758 | { | |
1759 | struct dm_snapshot *s = ti->private; | |
1760 | ||
1761 | stop_merge(s); | |
1762 | } | |
1763 | ||
c1f0c183 MS |
1764 | static int snapshot_preresume(struct dm_target *ti) |
1765 | { | |
1766 | int r = 0; | |
1767 | struct dm_snapshot *s = ti->private; | |
1768 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; | |
1769 | ||
1770 | down_read(&_origins_lock); | |
9d3b15c4 | 1771 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1772 | if (snap_src && snap_dest) { |
1773 | down_read(&snap_src->lock); | |
1774 | if (s == snap_src) { | |
1775 | DMERR("Unable to resume snapshot source until " | |
1776 | "handover completes."); | |
1777 | r = -EINVAL; | |
b83b2f29 | 1778 | } else if (!dm_suspended(snap_src->ti)) { |
c1f0c183 MS |
1779 | DMERR("Unable to perform snapshot handover until " |
1780 | "source is suspended."); | |
1781 | r = -EINVAL; | |
1782 | } | |
1783 | up_read(&snap_src->lock); | |
1784 | } | |
1785 | up_read(&_origins_lock); | |
1786 | ||
1787 | return r; | |
1788 | } | |
1789 | ||
1da177e4 LT |
1790 | static void snapshot_resume(struct dm_target *ti) |
1791 | { | |
028867ac | 1792 | struct dm_snapshot *s = ti->private; |
c1f0c183 MS |
1793 | struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; |
1794 | ||
1795 | down_read(&_origins_lock); | |
9d3b15c4 | 1796 | (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); |
c1f0c183 MS |
1797 | if (snap_src && snap_dest) { |
1798 | down_write(&snap_src->lock); | |
1799 | down_write_nested(&snap_dest->lock, SINGLE_DEPTH_NESTING); | |
1800 | __handover_exceptions(snap_src, snap_dest); | |
1801 | up_write(&snap_dest->lock); | |
1802 | up_write(&snap_src->lock); | |
1803 | } | |
1804 | up_read(&_origins_lock); | |
1805 | ||
1806 | /* Now we have correct chunk size, reregister */ | |
1807 | reregister_snapshot(s); | |
1da177e4 | 1808 | |
aa14edeb AK |
1809 | down_write(&s->lock); |
1810 | s->active = 1; | |
1811 | up_write(&s->lock); | |
1da177e4 LT |
1812 | } |
1813 | ||
542f9038 | 1814 | static uint32_t get_origin_minimum_chunksize(struct block_device *bdev) |
1e03f97e | 1815 | { |
542f9038 | 1816 | uint32_t min_chunksize; |
1e03f97e MP |
1817 | |
1818 | down_read(&_origins_lock); | |
1819 | min_chunksize = __minimum_chunk_size(__lookup_origin(bdev)); | |
1820 | up_read(&_origins_lock); | |
1821 | ||
1822 | return min_chunksize; | |
1823 | } | |
1824 | ||
1825 | static void snapshot_merge_resume(struct dm_target *ti) | |
1826 | { | |
1827 | struct dm_snapshot *s = ti->private; | |
1828 | ||
1829 | /* | |
1830 | * Handover exceptions from existing snapshot. | |
1831 | */ | |
1832 | snapshot_resume(ti); | |
1833 | ||
1834 | /* | |
542f9038 | 1835 | * snapshot-merge acts as an origin, so set ti->max_io_len |
1e03f97e | 1836 | */ |
542f9038 | 1837 | ti->max_io_len = get_origin_minimum_chunksize(s->origin->bdev); |
1e03f97e MP |
1838 | |
1839 | start_merge(s); | |
1840 | } | |
1841 | ||
fd7c092e MP |
1842 | static void snapshot_status(struct dm_target *ti, status_type_t type, |
1843 | unsigned status_flags, char *result, unsigned maxlen) | |
1da177e4 | 1844 | { |
2e4a31df | 1845 | unsigned sz = 0; |
028867ac | 1846 | struct dm_snapshot *snap = ti->private; |
1da177e4 LT |
1847 | |
1848 | switch (type) { | |
1849 | case STATUSTYPE_INFO: | |
94e76572 MP |
1850 | |
1851 | down_write(&snap->lock); | |
1852 | ||
1da177e4 | 1853 | if (!snap->valid) |
2e4a31df | 1854 | DMEMIT("Invalid"); |
d8ddb1cf MS |
1855 | else if (snap->merge_failed) |
1856 | DMEMIT("Merge failed"); | |
1da177e4 | 1857 | else { |
985903bb MS |
1858 | if (snap->store->type->usage) { |
1859 | sector_t total_sectors, sectors_allocated, | |
1860 | metadata_sectors; | |
1861 | snap->store->type->usage(snap->store, | |
1862 | &total_sectors, | |
1863 | §ors_allocated, | |
1864 | &metadata_sectors); | |
1865 | DMEMIT("%llu/%llu %llu", | |
1866 | (unsigned long long)sectors_allocated, | |
1867 | (unsigned long long)total_sectors, | |
1868 | (unsigned long long)metadata_sectors); | |
1da177e4 LT |
1869 | } |
1870 | else | |
2e4a31df | 1871 | DMEMIT("Unknown"); |
1da177e4 | 1872 | } |
94e76572 MP |
1873 | |
1874 | up_write(&snap->lock); | |
1875 | ||
1da177e4 LT |
1876 | break; |
1877 | ||
1878 | case STATUSTYPE_TABLE: | |
1879 | /* | |
1880 | * kdevname returns a static pointer so we need | |
1881 | * to make private copies if the output is to | |
1882 | * make sense. | |
1883 | */ | |
fc56f6fb | 1884 | DMEMIT("%s %s", snap->origin->name, snap->cow->name); |
1e302a92 JB |
1885 | snap->store->type->status(snap->store, type, result + sz, |
1886 | maxlen - sz); | |
1da177e4 LT |
1887 | break; |
1888 | } | |
1da177e4 LT |
1889 | } |
1890 | ||
8811f46c MS |
1891 | static int snapshot_iterate_devices(struct dm_target *ti, |
1892 | iterate_devices_callout_fn fn, void *data) | |
1893 | { | |
1894 | struct dm_snapshot *snap = ti->private; | |
1e5554c8 MP |
1895 | int r; |
1896 | ||
1897 | r = fn(ti, snap->origin, 0, ti->len, data); | |
8811f46c | 1898 | |
1e5554c8 MP |
1899 | if (!r) |
1900 | r = fn(ti, snap->cow, 0, get_dev_size(snap->cow->bdev), data); | |
1901 | ||
1902 | return r; | |
8811f46c MS |
1903 | } |
1904 | ||
1905 | ||
1da177e4 LT |
1906 | /*----------------------------------------------------------------- |
1907 | * Origin methods | |
1908 | *---------------------------------------------------------------*/ | |
9eaae8ff MP |
1909 | |
1910 | /* | |
1911 | * If no exceptions need creating, DM_MAPIO_REMAPPED is returned and any | |
1912 | * supplied bio was ignored. The caller may submit it immediately. | |
1913 | * (No remapping actually occurs as the origin is always a direct linear | |
1914 | * map.) | |
1915 | * | |
1916 | * If further exceptions are required, DM_MAPIO_SUBMITTED is returned | |
1917 | * and any supplied bio is added to a list to be submitted once all | |
1918 | * the necessary exceptions exist. | |
1919 | */ | |
1920 | static int __origin_write(struct list_head *snapshots, sector_t sector, | |
1921 | struct bio *bio) | |
1da177e4 | 1922 | { |
515ad66c | 1923 | int r = DM_MAPIO_REMAPPED; |
1da177e4 | 1924 | struct dm_snapshot *snap; |
1d4989c8 | 1925 | struct dm_exception *e; |
515ad66c MP |
1926 | struct dm_snap_pending_exception *pe; |
1927 | struct dm_snap_pending_exception *pe_to_start_now = NULL; | |
1928 | struct dm_snap_pending_exception *pe_to_start_last = NULL; | |
1da177e4 LT |
1929 | chunk_t chunk; |
1930 | ||
1931 | /* Do all the snapshots on this origin */ | |
1932 | list_for_each_entry (snap, snapshots, list) { | |
3452c2a1 MP |
1933 | /* |
1934 | * Don't make new exceptions in a merging snapshot | |
1935 | * because it has effectively been deleted | |
1936 | */ | |
1937 | if (dm_target_is_snapshot_merge(snap->ti)) | |
1938 | continue; | |
1939 | ||
76df1c65 AK |
1940 | down_write(&snap->lock); |
1941 | ||
aa14edeb AK |
1942 | /* Only deal with valid and active snapshots */ |
1943 | if (!snap->valid || !snap->active) | |
76df1c65 | 1944 | goto next_snapshot; |
1da177e4 | 1945 | |
d5e404c1 | 1946 | /* Nothing to do if writing beyond end of snapshot */ |
9eaae8ff | 1947 | if (sector >= dm_table_get_size(snap->ti->table)) |
76df1c65 | 1948 | goto next_snapshot; |
1da177e4 LT |
1949 | |
1950 | /* | |
1951 | * Remember, different snapshots can have | |
1952 | * different chunk sizes. | |
1953 | */ | |
9eaae8ff | 1954 | chunk = sector_to_chunk(snap->store, sector); |
1da177e4 LT |
1955 | |
1956 | /* | |
1957 | * Check exception table to see if block | |
1958 | * is already remapped in this snapshot | |
1959 | * and trigger an exception if not. | |
1960 | */ | |
3510cb94 | 1961 | e = dm_lookup_exception(&snap->complete, chunk); |
76df1c65 AK |
1962 | if (e) |
1963 | goto next_snapshot; | |
1964 | ||
2913808e | 1965 | pe = __lookup_pending_exception(snap, chunk); |
76df1c65 | 1966 | if (!pe) { |
c6621392 MP |
1967 | up_write(&snap->lock); |
1968 | pe = alloc_pending_exception(snap); | |
1969 | down_write(&snap->lock); | |
1970 | ||
1971 | if (!snap->valid) { | |
1972 | free_pending_exception(pe); | |
1973 | goto next_snapshot; | |
1974 | } | |
1975 | ||
3510cb94 | 1976 | e = dm_lookup_exception(&snap->complete, chunk); |
35bf659b MP |
1977 | if (e) { |
1978 | free_pending_exception(pe); | |
1979 | goto next_snapshot; | |
1980 | } | |
1981 | ||
c6621392 | 1982 | pe = __find_pending_exception(snap, pe, chunk); |
2913808e MP |
1983 | if (!pe) { |
1984 | __invalidate_snapshot(snap, -ENOMEM); | |
1985 | goto next_snapshot; | |
1986 | } | |
76df1c65 AK |
1987 | } |
1988 | ||
515ad66c | 1989 | r = DM_MAPIO_SUBMITTED; |
76df1c65 | 1990 | |
515ad66c MP |
1991 | /* |
1992 | * If an origin bio was supplied, queue it to wait for the | |
1993 | * completion of this exception, and start this one last, | |
1994 | * at the end of the function. | |
1995 | */ | |
1996 | if (bio) { | |
1997 | bio_list_add(&pe->origin_bios, bio); | |
1998 | bio = NULL; | |
76df1c65 | 1999 | |
515ad66c MP |
2000 | if (!pe->started) { |
2001 | pe->started = 1; | |
2002 | pe_to_start_last = pe; | |
2003 | } | |
76df1c65 AK |
2004 | } |
2005 | ||
2006 | if (!pe->started) { | |
2007 | pe->started = 1; | |
515ad66c | 2008 | pe_to_start_now = pe; |
1da177e4 LT |
2009 | } |
2010 | ||
a2d2b034 | 2011 | next_snapshot: |
1da177e4 | 2012 | up_write(&snap->lock); |
1da177e4 | 2013 | |
515ad66c MP |
2014 | if (pe_to_start_now) { |
2015 | start_copy(pe_to_start_now); | |
2016 | pe_to_start_now = NULL; | |
2017 | } | |
b4b610f6 AK |
2018 | } |
2019 | ||
1da177e4 | 2020 | /* |
515ad66c MP |
2021 | * Submit the exception against which the bio is queued last, |
2022 | * to give the other exceptions a head start. | |
1da177e4 | 2023 | */ |
515ad66c MP |
2024 | if (pe_to_start_last) |
2025 | start_copy(pe_to_start_last); | |
1da177e4 LT |
2026 | |
2027 | return r; | |
2028 | } | |
2029 | ||
2030 | /* | |
2031 | * Called on a write from the origin driver. | |
2032 | */ | |
2033 | static int do_origin(struct dm_dev *origin, struct bio *bio) | |
2034 | { | |
2035 | struct origin *o; | |
d2a7ad29 | 2036 | int r = DM_MAPIO_REMAPPED; |
1da177e4 LT |
2037 | |
2038 | down_read(&_origins_lock); | |
2039 | o = __lookup_origin(origin->bdev); | |
2040 | if (o) | |
9eaae8ff | 2041 | r = __origin_write(&o->snapshots, bio->bi_sector, bio); |
1da177e4 LT |
2042 | up_read(&_origins_lock); |
2043 | ||
2044 | return r; | |
2045 | } | |
2046 | ||
73dfd078 MP |
2047 | /* |
2048 | * Trigger exceptions in all non-merging snapshots. | |
2049 | * | |
2050 | * The chunk size of the merging snapshot may be larger than the chunk | |
2051 | * size of some other snapshot so we may need to reallocate multiple | |
2052 | * chunks in other snapshots. | |
2053 | * | |
2054 | * We scan all the overlapping exceptions in the other snapshots. | |
2055 | * Returns 1 if anything was reallocated and must be waited for, | |
2056 | * otherwise returns 0. | |
2057 | * | |
2058 | * size must be a multiple of merging_snap's chunk_size. | |
2059 | */ | |
2060 | static int origin_write_extent(struct dm_snapshot *merging_snap, | |
2061 | sector_t sector, unsigned size) | |
2062 | { | |
2063 | int must_wait = 0; | |
2064 | sector_t n; | |
2065 | struct origin *o; | |
2066 | ||
2067 | /* | |
542f9038 | 2068 | * The origin's __minimum_chunk_size() got stored in max_io_len |
73dfd078 MP |
2069 | * by snapshot_merge_resume(). |
2070 | */ | |
2071 | down_read(&_origins_lock); | |
2072 | o = __lookup_origin(merging_snap->origin->bdev); | |
542f9038 | 2073 | for (n = 0; n < size; n += merging_snap->ti->max_io_len) |
73dfd078 MP |
2074 | if (__origin_write(&o->snapshots, sector + n, NULL) == |
2075 | DM_MAPIO_SUBMITTED) | |
2076 | must_wait = 1; | |
2077 | up_read(&_origins_lock); | |
2078 | ||
2079 | return must_wait; | |
2080 | } | |
2081 | ||
1da177e4 LT |
2082 | /* |
2083 | * Origin: maps a linear range of a device, with hooks for snapshotting. | |
2084 | */ | |
2085 | ||
2086 | /* | |
2087 | * Construct an origin mapping: <dev_path> | |
2088 | * The context for an origin is merely a 'struct dm_dev *' | |
2089 | * pointing to the real device. | |
2090 | */ | |
2091 | static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
2092 | { | |
2093 | int r; | |
2094 | struct dm_dev *dev; | |
2095 | ||
2096 | if (argc != 1) { | |
72d94861 | 2097 | ti->error = "origin: incorrect number of arguments"; |
1da177e4 LT |
2098 | return -EINVAL; |
2099 | } | |
2100 | ||
8215d6ec | 2101 | r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev); |
1da177e4 LT |
2102 | if (r) { |
2103 | ti->error = "Cannot get target device"; | |
2104 | return r; | |
2105 | } | |
2106 | ||
2107 | ti->private = dev; | |
55a62eef | 2108 | ti->num_flush_bios = 1; |
494b3ee7 | 2109 | |
1da177e4 LT |
2110 | return 0; |
2111 | } | |
2112 | ||
2113 | static void origin_dtr(struct dm_target *ti) | |
2114 | { | |
028867ac | 2115 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2116 | dm_put_device(ti, dev); |
2117 | } | |
2118 | ||
7de3ee57 | 2119 | static int origin_map(struct dm_target *ti, struct bio *bio) |
1da177e4 | 2120 | { |
028867ac | 2121 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2122 | bio->bi_bdev = dev->bdev; |
2123 | ||
d87f4c14 | 2124 | if (bio->bi_rw & REQ_FLUSH) |
494b3ee7 MP |
2125 | return DM_MAPIO_REMAPPED; |
2126 | ||
1da177e4 | 2127 | /* Only tell snapshots if this is a write */ |
d2a7ad29 | 2128 | return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; |
1da177e4 LT |
2129 | } |
2130 | ||
1da177e4 | 2131 | /* |
542f9038 | 2132 | * Set the target "max_io_len" field to the minimum of all the snapshots' |
1da177e4 LT |
2133 | * chunk sizes. |
2134 | */ | |
2135 | static void origin_resume(struct dm_target *ti) | |
2136 | { | |
028867ac | 2137 | struct dm_dev *dev = ti->private; |
1da177e4 | 2138 | |
542f9038 | 2139 | ti->max_io_len = get_origin_minimum_chunksize(dev->bdev); |
1da177e4 LT |
2140 | } |
2141 | ||
fd7c092e MP |
2142 | static void origin_status(struct dm_target *ti, status_type_t type, |
2143 | unsigned status_flags, char *result, unsigned maxlen) | |
1da177e4 | 2144 | { |
028867ac | 2145 | struct dm_dev *dev = ti->private; |
1da177e4 LT |
2146 | |
2147 | switch (type) { | |
2148 | case STATUSTYPE_INFO: | |
2149 | result[0] = '\0'; | |
2150 | break; | |
2151 | ||
2152 | case STATUSTYPE_TABLE: | |
2153 | snprintf(result, maxlen, "%s", dev->name); | |
2154 | break; | |
2155 | } | |
1da177e4 LT |
2156 | } |
2157 | ||
b1d55528 MP |
2158 | static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
2159 | struct bio_vec *biovec, int max_size) | |
2160 | { | |
2161 | struct dm_dev *dev = ti->private; | |
2162 | struct request_queue *q = bdev_get_queue(dev->bdev); | |
2163 | ||
2164 | if (!q->merge_bvec_fn) | |
2165 | return max_size; | |
2166 | ||
2167 | bvm->bi_bdev = dev->bdev; | |
b1d55528 MP |
2168 | |
2169 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
2170 | } | |
2171 | ||
8811f46c MS |
2172 | static int origin_iterate_devices(struct dm_target *ti, |
2173 | iterate_devices_callout_fn fn, void *data) | |
2174 | { | |
2175 | struct dm_dev *dev = ti->private; | |
2176 | ||
2177 | return fn(ti, dev, 0, ti->len, data); | |
2178 | } | |
2179 | ||
1da177e4 LT |
2180 | static struct target_type origin_target = { |
2181 | .name = "snapshot-origin", | |
fd7c092e | 2182 | .version = {1, 8, 1}, |
1da177e4 LT |
2183 | .module = THIS_MODULE, |
2184 | .ctr = origin_ctr, | |
2185 | .dtr = origin_dtr, | |
2186 | .map = origin_map, | |
2187 | .resume = origin_resume, | |
2188 | .status = origin_status, | |
b1d55528 | 2189 | .merge = origin_merge, |
8811f46c | 2190 | .iterate_devices = origin_iterate_devices, |
1da177e4 LT |
2191 | }; |
2192 | ||
2193 | static struct target_type snapshot_target = { | |
2194 | .name = "snapshot", | |
fd7c092e | 2195 | .version = {1, 11, 1}, |
1da177e4 LT |
2196 | .module = THIS_MODULE, |
2197 | .ctr = snapshot_ctr, | |
2198 | .dtr = snapshot_dtr, | |
2199 | .map = snapshot_map, | |
cd45daff | 2200 | .end_io = snapshot_end_io, |
c1f0c183 | 2201 | .preresume = snapshot_preresume, |
1da177e4 LT |
2202 | .resume = snapshot_resume, |
2203 | .status = snapshot_status, | |
8811f46c | 2204 | .iterate_devices = snapshot_iterate_devices, |
1da177e4 LT |
2205 | }; |
2206 | ||
d698aa45 MP |
2207 | static struct target_type merge_target = { |
2208 | .name = dm_snapshot_merge_target_name, | |
42bc954f | 2209 | .version = {1, 2, 0}, |
d698aa45 MP |
2210 | .module = THIS_MODULE, |
2211 | .ctr = snapshot_ctr, | |
2212 | .dtr = snapshot_dtr, | |
3452c2a1 | 2213 | .map = snapshot_merge_map, |
d698aa45 | 2214 | .end_io = snapshot_end_io, |
1e03f97e | 2215 | .presuspend = snapshot_merge_presuspend, |
d698aa45 | 2216 | .preresume = snapshot_preresume, |
1e03f97e | 2217 | .resume = snapshot_merge_resume, |
d698aa45 MP |
2218 | .status = snapshot_status, |
2219 | .iterate_devices = snapshot_iterate_devices, | |
2220 | }; | |
2221 | ||
1da177e4 LT |
2222 | static int __init dm_snapshot_init(void) |
2223 | { | |
2224 | int r; | |
2225 | ||
4db6bfe0 AK |
2226 | r = dm_exception_store_init(); |
2227 | if (r) { | |
2228 | DMERR("Failed to initialize exception stores"); | |
2229 | return r; | |
2230 | } | |
2231 | ||
1da177e4 | 2232 | r = dm_register_target(&snapshot_target); |
d698aa45 | 2233 | if (r < 0) { |
1da177e4 | 2234 | DMERR("snapshot target register failed %d", r); |
034a186d | 2235 | goto bad_register_snapshot_target; |
1da177e4 LT |
2236 | } |
2237 | ||
2238 | r = dm_register_target(&origin_target); | |
2239 | if (r < 0) { | |
72d94861 | 2240 | DMERR("Origin target register failed %d", r); |
d698aa45 MP |
2241 | goto bad_register_origin_target; |
2242 | } | |
2243 | ||
2244 | r = dm_register_target(&merge_target); | |
2245 | if (r < 0) { | |
2246 | DMERR("Merge target register failed %d", r); | |
2247 | goto bad_register_merge_target; | |
1da177e4 LT |
2248 | } |
2249 | ||
2250 | r = init_origin_hash(); | |
2251 | if (r) { | |
2252 | DMERR("init_origin_hash failed."); | |
d698aa45 | 2253 | goto bad_origin_hash; |
1da177e4 LT |
2254 | } |
2255 | ||
1d4989c8 | 2256 | exception_cache = KMEM_CACHE(dm_exception, 0); |
1da177e4 LT |
2257 | if (!exception_cache) { |
2258 | DMERR("Couldn't create exception cache."); | |
2259 | r = -ENOMEM; | |
d698aa45 | 2260 | goto bad_exception_cache; |
1da177e4 LT |
2261 | } |
2262 | ||
028867ac | 2263 | pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0); |
1da177e4 LT |
2264 | if (!pending_cache) { |
2265 | DMERR("Couldn't create pending cache."); | |
2266 | r = -ENOMEM; | |
d698aa45 | 2267 | goto bad_pending_cache; |
1da177e4 LT |
2268 | } |
2269 | ||
1da177e4 LT |
2270 | return 0; |
2271 | ||
d698aa45 | 2272 | bad_pending_cache: |
1da177e4 | 2273 | kmem_cache_destroy(exception_cache); |
d698aa45 | 2274 | bad_exception_cache: |
1da177e4 | 2275 | exit_origin_hash(); |
d698aa45 MP |
2276 | bad_origin_hash: |
2277 | dm_unregister_target(&merge_target); | |
2278 | bad_register_merge_target: | |
1da177e4 | 2279 | dm_unregister_target(&origin_target); |
d698aa45 | 2280 | bad_register_origin_target: |
1da177e4 | 2281 | dm_unregister_target(&snapshot_target); |
034a186d JB |
2282 | bad_register_snapshot_target: |
2283 | dm_exception_store_exit(); | |
d698aa45 | 2284 | |
1da177e4 LT |
2285 | return r; |
2286 | } | |
2287 | ||
2288 | static void __exit dm_snapshot_exit(void) | |
2289 | { | |
10d3bd09 MP |
2290 | dm_unregister_target(&snapshot_target); |
2291 | dm_unregister_target(&origin_target); | |
d698aa45 | 2292 | dm_unregister_target(&merge_target); |
1da177e4 LT |
2293 | |
2294 | exit_origin_hash(); | |
1da177e4 LT |
2295 | kmem_cache_destroy(pending_cache); |
2296 | kmem_cache_destroy(exception_cache); | |
4db6bfe0 AK |
2297 | |
2298 | dm_exception_store_exit(); | |
1da177e4 LT |
2299 | } |
2300 | ||
2301 | /* Module hooks */ | |
2302 | module_init(dm_snapshot_init); | |
2303 | module_exit(dm_snapshot_exit); | |
2304 | ||
2305 | MODULE_DESCRIPTION(DM_NAME " snapshot target"); | |
2306 | MODULE_AUTHOR("Joe Thornber"); | |
2307 | MODULE_LICENSE("GPL"); | |
23cb2109 MP |
2308 | MODULE_ALIAS("dm-snapshot-origin"); |
2309 | MODULE_ALIAS("dm-snapshot-merge"); |