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991d9fa0 JT |
1 | /* |
2 | * Copyright (C) 2011 Red Hat UK. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
7 | #include "dm-thin-metadata.h" | |
8 | ||
9 | #include <linux/device-mapper.h> | |
10 | #include <linux/dm-io.h> | |
11 | #include <linux/dm-kcopyd.h> | |
12 | #include <linux/list.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/slab.h> | |
16 | ||
17 | #define DM_MSG_PREFIX "thin" | |
18 | ||
19 | /* | |
20 | * Tunable constants | |
21 | */ | |
22 | #define ENDIO_HOOK_POOL_SIZE 10240 | |
23 | #define DEFERRED_SET_SIZE 64 | |
24 | #define MAPPING_POOL_SIZE 1024 | |
25 | #define PRISON_CELLS 1024 | |
26 | ||
27 | /* | |
28 | * The block size of the device holding pool data must be | |
29 | * between 64KB and 1GB. | |
30 | */ | |
31 | #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT) | |
32 | #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) | |
33 | ||
34 | /* | |
35 | * The metadata device is currently limited in size. The limitation is | |
36 | * checked lower down in dm-space-map-metadata, but we also check it here | |
37 | * so we can fail early. | |
38 | * | |
39 | * We have one block of index, which can hold 255 index entries. Each | |
40 | * index entry contains allocation info about 16k metadata blocks. | |
41 | */ | |
42 | #define METADATA_DEV_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT))) | |
43 | ||
44 | /* | |
45 | * Device id is restricted to 24 bits. | |
46 | */ | |
47 | #define MAX_DEV_ID ((1 << 24) - 1) | |
48 | ||
49 | /* | |
50 | * How do we handle breaking sharing of data blocks? | |
51 | * ================================================= | |
52 | * | |
53 | * We use a standard copy-on-write btree to store the mappings for the | |
54 | * devices (note I'm talking about copy-on-write of the metadata here, not | |
55 | * the data). When you take an internal snapshot you clone the root node | |
56 | * of the origin btree. After this there is no concept of an origin or a | |
57 | * snapshot. They are just two device trees that happen to point to the | |
58 | * same data blocks. | |
59 | * | |
60 | * When we get a write in we decide if it's to a shared data block using | |
61 | * some timestamp magic. If it is, we have to break sharing. | |
62 | * | |
63 | * Let's say we write to a shared block in what was the origin. The | |
64 | * steps are: | |
65 | * | |
66 | * i) plug io further to this physical block. (see bio_prison code). | |
67 | * | |
68 | * ii) quiesce any read io to that shared data block. Obviously | |
69 | * including all devices that share this block. (see deferred_set code) | |
70 | * | |
71 | * iii) copy the data block to a newly allocate block. This step can be | |
72 | * missed out if the io covers the block. (schedule_copy). | |
73 | * | |
74 | * iv) insert the new mapping into the origin's btree | |
75 | * (process_prepared_mappings). This act of inserting breaks some | |
76 | * sharing of btree nodes between the two devices. Breaking sharing only | |
77 | * effects the btree of that specific device. Btrees for the other | |
78 | * devices that share the block never change. The btree for the origin | |
79 | * device as it was after the last commit is untouched, ie. we're using | |
80 | * persistent data structures in the functional programming sense. | |
81 | * | |
82 | * v) unplug io to this physical block, including the io that triggered | |
83 | * the breaking of sharing. | |
84 | * | |
85 | * Steps (ii) and (iii) occur in parallel. | |
86 | * | |
87 | * The metadata _doesn't_ need to be committed before the io continues. We | |
88 | * get away with this because the io is always written to a _new_ block. | |
89 | * If there's a crash, then: | |
90 | * | |
91 | * - The origin mapping will point to the old origin block (the shared | |
92 | * one). This will contain the data as it was before the io that triggered | |
93 | * the breaking of sharing came in. | |
94 | * | |
95 | * - The snap mapping still points to the old block. As it would after | |
96 | * the commit. | |
97 | * | |
98 | * The downside of this scheme is the timestamp magic isn't perfect, and | |
99 | * will continue to think that data block in the snapshot device is shared | |
100 | * even after the write to the origin has broken sharing. I suspect data | |
101 | * blocks will typically be shared by many different devices, so we're | |
102 | * breaking sharing n + 1 times, rather than n, where n is the number of | |
103 | * devices that reference this data block. At the moment I think the | |
104 | * benefits far, far outweigh the disadvantages. | |
105 | */ | |
106 | ||
107 | /*----------------------------------------------------------------*/ | |
108 | ||
109 | /* | |
110 | * Sometimes we can't deal with a bio straight away. We put them in prison | |
111 | * where they can't cause any mischief. Bios are put in a cell identified | |
112 | * by a key, multiple bios can be in the same cell. When the cell is | |
113 | * subsequently unlocked the bios become available. | |
114 | */ | |
115 | struct bio_prison; | |
116 | ||
117 | struct cell_key { | |
118 | int virtual; | |
119 | dm_thin_id dev; | |
120 | dm_block_t block; | |
121 | }; | |
122 | ||
123 | struct cell { | |
124 | struct hlist_node list; | |
125 | struct bio_prison *prison; | |
126 | struct cell_key key; | |
127 | unsigned count; | |
128 | struct bio_list bios; | |
129 | }; | |
130 | ||
131 | struct bio_prison { | |
132 | spinlock_t lock; | |
133 | mempool_t *cell_pool; | |
134 | ||
135 | unsigned nr_buckets; | |
136 | unsigned hash_mask; | |
137 | struct hlist_head *cells; | |
138 | }; | |
139 | ||
140 | static uint32_t calc_nr_buckets(unsigned nr_cells) | |
141 | { | |
142 | uint32_t n = 128; | |
143 | ||
144 | nr_cells /= 4; | |
145 | nr_cells = min(nr_cells, 8192u); | |
146 | ||
147 | while (n < nr_cells) | |
148 | n <<= 1; | |
149 | ||
150 | return n; | |
151 | } | |
152 | ||
153 | /* | |
154 | * @nr_cells should be the number of cells you want in use _concurrently_. | |
155 | * Don't confuse it with the number of distinct keys. | |
156 | */ | |
157 | static struct bio_prison *prison_create(unsigned nr_cells) | |
158 | { | |
159 | unsigned i; | |
160 | uint32_t nr_buckets = calc_nr_buckets(nr_cells); | |
161 | size_t len = sizeof(struct bio_prison) + | |
162 | (sizeof(struct hlist_head) * nr_buckets); | |
163 | struct bio_prison *prison = kmalloc(len, GFP_KERNEL); | |
164 | ||
165 | if (!prison) | |
166 | return NULL; | |
167 | ||
168 | spin_lock_init(&prison->lock); | |
169 | prison->cell_pool = mempool_create_kmalloc_pool(nr_cells, | |
170 | sizeof(struct cell)); | |
171 | if (!prison->cell_pool) { | |
172 | kfree(prison); | |
173 | return NULL; | |
174 | } | |
175 | ||
176 | prison->nr_buckets = nr_buckets; | |
177 | prison->hash_mask = nr_buckets - 1; | |
178 | prison->cells = (struct hlist_head *) (prison + 1); | |
179 | for (i = 0; i < nr_buckets; i++) | |
180 | INIT_HLIST_HEAD(prison->cells + i); | |
181 | ||
182 | return prison; | |
183 | } | |
184 | ||
185 | static void prison_destroy(struct bio_prison *prison) | |
186 | { | |
187 | mempool_destroy(prison->cell_pool); | |
188 | kfree(prison); | |
189 | } | |
190 | ||
191 | static uint32_t hash_key(struct bio_prison *prison, struct cell_key *key) | |
192 | { | |
193 | const unsigned long BIG_PRIME = 4294967291UL; | |
194 | uint64_t hash = key->block * BIG_PRIME; | |
195 | ||
196 | return (uint32_t) (hash & prison->hash_mask); | |
197 | } | |
198 | ||
199 | static int keys_equal(struct cell_key *lhs, struct cell_key *rhs) | |
200 | { | |
201 | return (lhs->virtual == rhs->virtual) && | |
202 | (lhs->dev == rhs->dev) && | |
203 | (lhs->block == rhs->block); | |
204 | } | |
205 | ||
206 | static struct cell *__search_bucket(struct hlist_head *bucket, | |
207 | struct cell_key *key) | |
208 | { | |
209 | struct cell *cell; | |
210 | struct hlist_node *tmp; | |
211 | ||
212 | hlist_for_each_entry(cell, tmp, bucket, list) | |
213 | if (keys_equal(&cell->key, key)) | |
214 | return cell; | |
215 | ||
216 | return NULL; | |
217 | } | |
218 | ||
219 | /* | |
220 | * This may block if a new cell needs allocating. You must ensure that | |
221 | * cells will be unlocked even if the calling thread is blocked. | |
222 | * | |
223 | * Returns the number of entries in the cell prior to the new addition | |
224 | * or < 0 on failure. | |
225 | */ | |
226 | static int bio_detain(struct bio_prison *prison, struct cell_key *key, | |
227 | struct bio *inmate, struct cell **ref) | |
228 | { | |
229 | int r; | |
230 | unsigned long flags; | |
231 | uint32_t hash = hash_key(prison, key); | |
232 | struct cell *uninitialized_var(cell), *cell2 = NULL; | |
233 | ||
234 | BUG_ON(hash > prison->nr_buckets); | |
235 | ||
236 | spin_lock_irqsave(&prison->lock, flags); | |
237 | cell = __search_bucket(prison->cells + hash, key); | |
238 | ||
239 | if (!cell) { | |
240 | /* | |
241 | * Allocate a new cell | |
242 | */ | |
243 | spin_unlock_irqrestore(&prison->lock, flags); | |
244 | cell2 = mempool_alloc(prison->cell_pool, GFP_NOIO); | |
245 | spin_lock_irqsave(&prison->lock, flags); | |
246 | ||
247 | /* | |
248 | * We've been unlocked, so we have to double check that | |
249 | * nobody else has inserted this cell in the meantime. | |
250 | */ | |
251 | cell = __search_bucket(prison->cells + hash, key); | |
252 | ||
253 | if (!cell) { | |
254 | cell = cell2; | |
255 | cell2 = NULL; | |
256 | ||
257 | cell->prison = prison; | |
258 | memcpy(&cell->key, key, sizeof(cell->key)); | |
259 | cell->count = 0; | |
260 | bio_list_init(&cell->bios); | |
261 | hlist_add_head(&cell->list, prison->cells + hash); | |
262 | } | |
263 | } | |
264 | ||
265 | r = cell->count++; | |
266 | bio_list_add(&cell->bios, inmate); | |
267 | spin_unlock_irqrestore(&prison->lock, flags); | |
268 | ||
269 | if (cell2) | |
270 | mempool_free(cell2, prison->cell_pool); | |
271 | ||
272 | *ref = cell; | |
273 | ||
274 | return r; | |
275 | } | |
276 | ||
277 | /* | |
278 | * @inmates must have been initialised prior to this call | |
279 | */ | |
280 | static void __cell_release(struct cell *cell, struct bio_list *inmates) | |
281 | { | |
282 | struct bio_prison *prison = cell->prison; | |
283 | ||
284 | hlist_del(&cell->list); | |
285 | ||
286 | if (inmates) | |
287 | bio_list_merge(inmates, &cell->bios); | |
288 | ||
289 | mempool_free(cell, prison->cell_pool); | |
290 | } | |
291 | ||
292 | static void cell_release(struct cell *cell, struct bio_list *bios) | |
293 | { | |
294 | unsigned long flags; | |
295 | struct bio_prison *prison = cell->prison; | |
296 | ||
297 | spin_lock_irqsave(&prison->lock, flags); | |
298 | __cell_release(cell, bios); | |
299 | spin_unlock_irqrestore(&prison->lock, flags); | |
300 | } | |
301 | ||
302 | /* | |
303 | * There are a couple of places where we put a bio into a cell briefly | |
304 | * before taking it out again. In these situations we know that no other | |
305 | * bio may be in the cell. This function releases the cell, and also does | |
306 | * a sanity check. | |
307 | */ | |
308 | static void cell_release_singleton(struct cell *cell, struct bio *bio) | |
309 | { | |
310 | struct bio_prison *prison = cell->prison; | |
311 | struct bio_list bios; | |
312 | struct bio *b; | |
313 | unsigned long flags; | |
314 | ||
315 | bio_list_init(&bios); | |
316 | ||
317 | spin_lock_irqsave(&prison->lock, flags); | |
318 | __cell_release(cell, &bios); | |
319 | spin_unlock_irqrestore(&prison->lock, flags); | |
320 | ||
321 | b = bio_list_pop(&bios); | |
322 | BUG_ON(b != bio); | |
323 | BUG_ON(!bio_list_empty(&bios)); | |
324 | } | |
325 | ||
326 | static void cell_error(struct cell *cell) | |
327 | { | |
328 | struct bio_prison *prison = cell->prison; | |
329 | struct bio_list bios; | |
330 | struct bio *bio; | |
331 | unsigned long flags; | |
332 | ||
333 | bio_list_init(&bios); | |
334 | ||
335 | spin_lock_irqsave(&prison->lock, flags); | |
336 | __cell_release(cell, &bios); | |
337 | spin_unlock_irqrestore(&prison->lock, flags); | |
338 | ||
339 | while ((bio = bio_list_pop(&bios))) | |
340 | bio_io_error(bio); | |
341 | } | |
342 | ||
343 | /*----------------------------------------------------------------*/ | |
344 | ||
345 | /* | |
346 | * We use the deferred set to keep track of pending reads to shared blocks. | |
347 | * We do this to ensure the new mapping caused by a write isn't performed | |
348 | * until these prior reads have completed. Otherwise the insertion of the | |
349 | * new mapping could free the old block that the read bios are mapped to. | |
350 | */ | |
351 | ||
352 | struct deferred_set; | |
353 | struct deferred_entry { | |
354 | struct deferred_set *ds; | |
355 | unsigned count; | |
356 | struct list_head work_items; | |
357 | }; | |
358 | ||
359 | struct deferred_set { | |
360 | spinlock_t lock; | |
361 | unsigned current_entry; | |
362 | unsigned sweeper; | |
363 | struct deferred_entry entries[DEFERRED_SET_SIZE]; | |
364 | }; | |
365 | ||
366 | static void ds_init(struct deferred_set *ds) | |
367 | { | |
368 | int i; | |
369 | ||
370 | spin_lock_init(&ds->lock); | |
371 | ds->current_entry = 0; | |
372 | ds->sweeper = 0; | |
373 | for (i = 0; i < DEFERRED_SET_SIZE; i++) { | |
374 | ds->entries[i].ds = ds; | |
375 | ds->entries[i].count = 0; | |
376 | INIT_LIST_HEAD(&ds->entries[i].work_items); | |
377 | } | |
378 | } | |
379 | ||
380 | static struct deferred_entry *ds_inc(struct deferred_set *ds) | |
381 | { | |
382 | unsigned long flags; | |
383 | struct deferred_entry *entry; | |
384 | ||
385 | spin_lock_irqsave(&ds->lock, flags); | |
386 | entry = ds->entries + ds->current_entry; | |
387 | entry->count++; | |
388 | spin_unlock_irqrestore(&ds->lock, flags); | |
389 | ||
390 | return entry; | |
391 | } | |
392 | ||
393 | static unsigned ds_next(unsigned index) | |
394 | { | |
395 | return (index + 1) % DEFERRED_SET_SIZE; | |
396 | } | |
397 | ||
398 | static void __sweep(struct deferred_set *ds, struct list_head *head) | |
399 | { | |
400 | while ((ds->sweeper != ds->current_entry) && | |
401 | !ds->entries[ds->sweeper].count) { | |
402 | list_splice_init(&ds->entries[ds->sweeper].work_items, head); | |
403 | ds->sweeper = ds_next(ds->sweeper); | |
404 | } | |
405 | ||
406 | if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count) | |
407 | list_splice_init(&ds->entries[ds->sweeper].work_items, head); | |
408 | } | |
409 | ||
410 | static void ds_dec(struct deferred_entry *entry, struct list_head *head) | |
411 | { | |
412 | unsigned long flags; | |
413 | ||
414 | spin_lock_irqsave(&entry->ds->lock, flags); | |
415 | BUG_ON(!entry->count); | |
416 | --entry->count; | |
417 | __sweep(entry->ds, head); | |
418 | spin_unlock_irqrestore(&entry->ds->lock, flags); | |
419 | } | |
420 | ||
421 | /* | |
422 | * Returns 1 if deferred or 0 if no pending items to delay job. | |
423 | */ | |
424 | static int ds_add_work(struct deferred_set *ds, struct list_head *work) | |
425 | { | |
426 | int r = 1; | |
427 | unsigned long flags; | |
428 | unsigned next_entry; | |
429 | ||
430 | spin_lock_irqsave(&ds->lock, flags); | |
431 | if ((ds->sweeper == ds->current_entry) && | |
432 | !ds->entries[ds->current_entry].count) | |
433 | r = 0; | |
434 | else { | |
435 | list_add(work, &ds->entries[ds->current_entry].work_items); | |
436 | next_entry = ds_next(ds->current_entry); | |
437 | if (!ds->entries[next_entry].count) | |
438 | ds->current_entry = next_entry; | |
439 | } | |
440 | spin_unlock_irqrestore(&ds->lock, flags); | |
441 | ||
442 | return r; | |
443 | } | |
444 | ||
445 | /*----------------------------------------------------------------*/ | |
446 | ||
447 | /* | |
448 | * Key building. | |
449 | */ | |
450 | static void build_data_key(struct dm_thin_device *td, | |
451 | dm_block_t b, struct cell_key *key) | |
452 | { | |
453 | key->virtual = 0; | |
454 | key->dev = dm_thin_dev_id(td); | |
455 | key->block = b; | |
456 | } | |
457 | ||
458 | static void build_virtual_key(struct dm_thin_device *td, dm_block_t b, | |
459 | struct cell_key *key) | |
460 | { | |
461 | key->virtual = 1; | |
462 | key->dev = dm_thin_dev_id(td); | |
463 | key->block = b; | |
464 | } | |
465 | ||
466 | /*----------------------------------------------------------------*/ | |
467 | ||
468 | /* | |
469 | * A pool device ties together a metadata device and a data device. It | |
470 | * also provides the interface for creating and destroying internal | |
471 | * devices. | |
472 | */ | |
473 | struct new_mapping; | |
474 | struct pool { | |
475 | struct list_head list; | |
476 | struct dm_target *ti; /* Only set if a pool target is bound */ | |
477 | ||
478 | struct mapped_device *pool_md; | |
479 | struct block_device *md_dev; | |
480 | struct dm_pool_metadata *pmd; | |
481 | ||
482 | uint32_t sectors_per_block; | |
483 | unsigned block_shift; | |
484 | dm_block_t offset_mask; | |
485 | dm_block_t low_water_blocks; | |
486 | ||
487 | unsigned zero_new_blocks:1; | |
488 | unsigned low_water_triggered:1; /* A dm event has been sent */ | |
489 | unsigned no_free_space:1; /* A -ENOSPC warning has been issued */ | |
490 | ||
491 | struct bio_prison *prison; | |
492 | struct dm_kcopyd_client *copier; | |
493 | ||
494 | struct workqueue_struct *wq; | |
495 | struct work_struct worker; | |
496 | ||
497 | unsigned ref_count; | |
498 | ||
499 | spinlock_t lock; | |
500 | struct bio_list deferred_bios; | |
501 | struct bio_list deferred_flush_bios; | |
502 | struct list_head prepared_mappings; | |
503 | ||
504 | struct bio_list retry_on_resume_list; | |
505 | ||
506 | struct deferred_set ds; /* FIXME: move to thin_c */ | |
507 | ||
508 | struct new_mapping *next_mapping; | |
509 | mempool_t *mapping_pool; | |
510 | mempool_t *endio_hook_pool; | |
511 | }; | |
512 | ||
513 | /* | |
514 | * Target context for a pool. | |
515 | */ | |
516 | struct pool_c { | |
517 | struct dm_target *ti; | |
518 | struct pool *pool; | |
519 | struct dm_dev *data_dev; | |
520 | struct dm_dev *metadata_dev; | |
521 | struct dm_target_callbacks callbacks; | |
522 | ||
523 | dm_block_t low_water_blocks; | |
524 | unsigned zero_new_blocks:1; | |
525 | }; | |
526 | ||
527 | /* | |
528 | * Target context for a thin. | |
529 | */ | |
530 | struct thin_c { | |
531 | struct dm_dev *pool_dev; | |
532 | dm_thin_id dev_id; | |
533 | ||
534 | struct pool *pool; | |
535 | struct dm_thin_device *td; | |
536 | }; | |
537 | ||
538 | /*----------------------------------------------------------------*/ | |
539 | ||
540 | /* | |
541 | * A global list of pools that uses a struct mapped_device as a key. | |
542 | */ | |
543 | static struct dm_thin_pool_table { | |
544 | struct mutex mutex; | |
545 | struct list_head pools; | |
546 | } dm_thin_pool_table; | |
547 | ||
548 | static void pool_table_init(void) | |
549 | { | |
550 | mutex_init(&dm_thin_pool_table.mutex); | |
551 | INIT_LIST_HEAD(&dm_thin_pool_table.pools); | |
552 | } | |
553 | ||
554 | static void __pool_table_insert(struct pool *pool) | |
555 | { | |
556 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); | |
557 | list_add(&pool->list, &dm_thin_pool_table.pools); | |
558 | } | |
559 | ||
560 | static void __pool_table_remove(struct pool *pool) | |
561 | { | |
562 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); | |
563 | list_del(&pool->list); | |
564 | } | |
565 | ||
566 | static struct pool *__pool_table_lookup(struct mapped_device *md) | |
567 | { | |
568 | struct pool *pool = NULL, *tmp; | |
569 | ||
570 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); | |
571 | ||
572 | list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { | |
573 | if (tmp->pool_md == md) { | |
574 | pool = tmp; | |
575 | break; | |
576 | } | |
577 | } | |
578 | ||
579 | return pool; | |
580 | } | |
581 | ||
582 | static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev) | |
583 | { | |
584 | struct pool *pool = NULL, *tmp; | |
585 | ||
586 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); | |
587 | ||
588 | list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { | |
589 | if (tmp->md_dev == md_dev) { | |
590 | pool = tmp; | |
591 | break; | |
592 | } | |
593 | } | |
594 | ||
595 | return pool; | |
596 | } | |
597 | ||
598 | /*----------------------------------------------------------------*/ | |
599 | ||
600 | static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master) | |
601 | { | |
602 | struct bio *bio; | |
603 | struct bio_list bios; | |
604 | ||
605 | bio_list_init(&bios); | |
606 | bio_list_merge(&bios, master); | |
607 | bio_list_init(master); | |
608 | ||
609 | while ((bio = bio_list_pop(&bios))) { | |
610 | if (dm_get_mapinfo(bio)->ptr == tc) | |
611 | bio_endio(bio, DM_ENDIO_REQUEUE); | |
612 | else | |
613 | bio_list_add(master, bio); | |
614 | } | |
615 | } | |
616 | ||
617 | static void requeue_io(struct thin_c *tc) | |
618 | { | |
619 | struct pool *pool = tc->pool; | |
620 | unsigned long flags; | |
621 | ||
622 | spin_lock_irqsave(&pool->lock, flags); | |
623 | __requeue_bio_list(tc, &pool->deferred_bios); | |
624 | __requeue_bio_list(tc, &pool->retry_on_resume_list); | |
625 | spin_unlock_irqrestore(&pool->lock, flags); | |
626 | } | |
627 | ||
628 | /* | |
629 | * This section of code contains the logic for processing a thin device's IO. | |
630 | * Much of the code depends on pool object resources (lists, workqueues, etc) | |
631 | * but most is exclusively called from the thin target rather than the thin-pool | |
632 | * target. | |
633 | */ | |
634 | ||
635 | static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio) | |
636 | { | |
637 | return bio->bi_sector >> tc->pool->block_shift; | |
638 | } | |
639 | ||
640 | static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block) | |
641 | { | |
642 | struct pool *pool = tc->pool; | |
643 | ||
644 | bio->bi_bdev = tc->pool_dev->bdev; | |
645 | bio->bi_sector = (block << pool->block_shift) + | |
646 | (bio->bi_sector & pool->offset_mask); | |
647 | } | |
648 | ||
649 | static void remap_and_issue(struct thin_c *tc, struct bio *bio, | |
650 | dm_block_t block) | |
651 | { | |
652 | struct pool *pool = tc->pool; | |
653 | unsigned long flags; | |
654 | ||
655 | remap(tc, bio, block); | |
656 | ||
657 | /* | |
658 | * Batch together any FUA/FLUSH bios we find and then issue | |
659 | * a single commit for them in process_deferred_bios(). | |
660 | */ | |
661 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { | |
662 | spin_lock_irqsave(&pool->lock, flags); | |
663 | bio_list_add(&pool->deferred_flush_bios, bio); | |
664 | spin_unlock_irqrestore(&pool->lock, flags); | |
665 | } else | |
666 | generic_make_request(bio); | |
667 | } | |
668 | ||
669 | /* | |
670 | * wake_worker() is used when new work is queued and when pool_resume is | |
671 | * ready to continue deferred IO processing. | |
672 | */ | |
673 | static void wake_worker(struct pool *pool) | |
674 | { | |
675 | queue_work(pool->wq, &pool->worker); | |
676 | } | |
677 | ||
678 | /*----------------------------------------------------------------*/ | |
679 | ||
680 | /* | |
681 | * Bio endio functions. | |
682 | */ | |
683 | struct endio_hook { | |
684 | struct thin_c *tc; | |
685 | bio_end_io_t *saved_bi_end_io; | |
686 | struct deferred_entry *entry; | |
687 | }; | |
688 | ||
689 | struct new_mapping { | |
690 | struct list_head list; | |
691 | ||
692 | int prepared; | |
693 | ||
694 | struct thin_c *tc; | |
695 | dm_block_t virt_block; | |
696 | dm_block_t data_block; | |
697 | struct cell *cell; | |
698 | int err; | |
699 | ||
700 | /* | |
701 | * If the bio covers the whole area of a block then we can avoid | |
702 | * zeroing or copying. Instead this bio is hooked. The bio will | |
703 | * still be in the cell, so care has to be taken to avoid issuing | |
704 | * the bio twice. | |
705 | */ | |
706 | struct bio *bio; | |
707 | bio_end_io_t *saved_bi_end_io; | |
708 | }; | |
709 | ||
710 | static void __maybe_add_mapping(struct new_mapping *m) | |
711 | { | |
712 | struct pool *pool = m->tc->pool; | |
713 | ||
714 | if (list_empty(&m->list) && m->prepared) { | |
715 | list_add(&m->list, &pool->prepared_mappings); | |
716 | wake_worker(pool); | |
717 | } | |
718 | } | |
719 | ||
720 | static void copy_complete(int read_err, unsigned long write_err, void *context) | |
721 | { | |
722 | unsigned long flags; | |
723 | struct new_mapping *m = context; | |
724 | struct pool *pool = m->tc->pool; | |
725 | ||
726 | m->err = read_err || write_err ? -EIO : 0; | |
727 | ||
728 | spin_lock_irqsave(&pool->lock, flags); | |
729 | m->prepared = 1; | |
730 | __maybe_add_mapping(m); | |
731 | spin_unlock_irqrestore(&pool->lock, flags); | |
732 | } | |
733 | ||
734 | static void overwrite_endio(struct bio *bio, int err) | |
735 | { | |
736 | unsigned long flags; | |
737 | struct new_mapping *m = dm_get_mapinfo(bio)->ptr; | |
738 | struct pool *pool = m->tc->pool; | |
739 | ||
740 | m->err = err; | |
741 | ||
742 | spin_lock_irqsave(&pool->lock, flags); | |
743 | m->prepared = 1; | |
744 | __maybe_add_mapping(m); | |
745 | spin_unlock_irqrestore(&pool->lock, flags); | |
746 | } | |
747 | ||
748 | static void shared_read_endio(struct bio *bio, int err) | |
749 | { | |
750 | struct list_head mappings; | |
751 | struct new_mapping *m, *tmp; | |
752 | struct endio_hook *h = dm_get_mapinfo(bio)->ptr; | |
753 | unsigned long flags; | |
754 | struct pool *pool = h->tc->pool; | |
755 | ||
756 | bio->bi_end_io = h->saved_bi_end_io; | |
757 | bio_endio(bio, err); | |
758 | ||
759 | INIT_LIST_HEAD(&mappings); | |
760 | ds_dec(h->entry, &mappings); | |
761 | ||
762 | spin_lock_irqsave(&pool->lock, flags); | |
763 | list_for_each_entry_safe(m, tmp, &mappings, list) { | |
764 | list_del(&m->list); | |
765 | INIT_LIST_HEAD(&m->list); | |
766 | __maybe_add_mapping(m); | |
767 | } | |
768 | spin_unlock_irqrestore(&pool->lock, flags); | |
769 | ||
770 | mempool_free(h, pool->endio_hook_pool); | |
771 | } | |
772 | ||
773 | /*----------------------------------------------------------------*/ | |
774 | ||
775 | /* | |
776 | * Workqueue. | |
777 | */ | |
778 | ||
779 | /* | |
780 | * Prepared mapping jobs. | |
781 | */ | |
782 | ||
783 | /* | |
784 | * This sends the bios in the cell back to the deferred_bios list. | |
785 | */ | |
786 | static void cell_defer(struct thin_c *tc, struct cell *cell, | |
787 | dm_block_t data_block) | |
788 | { | |
789 | struct pool *pool = tc->pool; | |
790 | unsigned long flags; | |
791 | ||
792 | spin_lock_irqsave(&pool->lock, flags); | |
793 | cell_release(cell, &pool->deferred_bios); | |
794 | spin_unlock_irqrestore(&tc->pool->lock, flags); | |
795 | ||
796 | wake_worker(pool); | |
797 | } | |
798 | ||
799 | /* | |
800 | * Same as cell_defer above, except it omits one particular detainee, | |
801 | * a write bio that covers the block and has already been processed. | |
802 | */ | |
803 | static void cell_defer_except(struct thin_c *tc, struct cell *cell, | |
804 | struct bio *exception) | |
805 | { | |
806 | struct bio_list bios; | |
807 | struct bio *bio; | |
808 | struct pool *pool = tc->pool; | |
809 | unsigned long flags; | |
810 | ||
811 | bio_list_init(&bios); | |
812 | cell_release(cell, &bios); | |
813 | ||
814 | spin_lock_irqsave(&pool->lock, flags); | |
815 | while ((bio = bio_list_pop(&bios))) | |
816 | if (bio != exception) | |
817 | bio_list_add(&pool->deferred_bios, bio); | |
818 | spin_unlock_irqrestore(&pool->lock, flags); | |
819 | ||
820 | wake_worker(pool); | |
821 | } | |
822 | ||
823 | static void process_prepared_mapping(struct new_mapping *m) | |
824 | { | |
825 | struct thin_c *tc = m->tc; | |
826 | struct bio *bio; | |
827 | int r; | |
828 | ||
829 | bio = m->bio; | |
830 | if (bio) | |
831 | bio->bi_end_io = m->saved_bi_end_io; | |
832 | ||
833 | if (m->err) { | |
834 | cell_error(m->cell); | |
835 | return; | |
836 | } | |
837 | ||
838 | /* | |
839 | * Commit the prepared block into the mapping btree. | |
840 | * Any I/O for this block arriving after this point will get | |
841 | * remapped to it directly. | |
842 | */ | |
843 | r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block); | |
844 | if (r) { | |
845 | DMERR("dm_thin_insert_block() failed"); | |
846 | cell_error(m->cell); | |
847 | return; | |
848 | } | |
849 | ||
850 | /* | |
851 | * Release any bios held while the block was being provisioned. | |
852 | * If we are processing a write bio that completely covers the block, | |
853 | * we already processed it so can ignore it now when processing | |
854 | * the bios in the cell. | |
855 | */ | |
856 | if (bio) { | |
857 | cell_defer_except(tc, m->cell, bio); | |
858 | bio_endio(bio, 0); | |
859 | } else | |
860 | cell_defer(tc, m->cell, m->data_block); | |
861 | ||
862 | list_del(&m->list); | |
863 | mempool_free(m, tc->pool->mapping_pool); | |
864 | } | |
865 | ||
866 | static void process_prepared_mappings(struct pool *pool) | |
867 | { | |
868 | unsigned long flags; | |
869 | struct list_head maps; | |
870 | struct new_mapping *m, *tmp; | |
871 | ||
872 | INIT_LIST_HEAD(&maps); | |
873 | spin_lock_irqsave(&pool->lock, flags); | |
874 | list_splice_init(&pool->prepared_mappings, &maps); | |
875 | spin_unlock_irqrestore(&pool->lock, flags); | |
876 | ||
877 | list_for_each_entry_safe(m, tmp, &maps, list) | |
878 | process_prepared_mapping(m); | |
879 | } | |
880 | ||
881 | /* | |
882 | * Deferred bio jobs. | |
883 | */ | |
884 | static int io_overwrites_block(struct pool *pool, struct bio *bio) | |
885 | { | |
886 | return ((bio_data_dir(bio) == WRITE) && | |
887 | !(bio->bi_sector & pool->offset_mask)) && | |
888 | (bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT)); | |
889 | } | |
890 | ||
891 | static void save_and_set_endio(struct bio *bio, bio_end_io_t **save, | |
892 | bio_end_io_t *fn) | |
893 | { | |
894 | *save = bio->bi_end_io; | |
895 | bio->bi_end_io = fn; | |
896 | } | |
897 | ||
898 | static int ensure_next_mapping(struct pool *pool) | |
899 | { | |
900 | if (pool->next_mapping) | |
901 | return 0; | |
902 | ||
903 | pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC); | |
904 | ||
905 | return pool->next_mapping ? 0 : -ENOMEM; | |
906 | } | |
907 | ||
908 | static struct new_mapping *get_next_mapping(struct pool *pool) | |
909 | { | |
910 | struct new_mapping *r = pool->next_mapping; | |
911 | ||
912 | BUG_ON(!pool->next_mapping); | |
913 | ||
914 | pool->next_mapping = NULL; | |
915 | ||
916 | return r; | |
917 | } | |
918 | ||
919 | static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, | |
920 | dm_block_t data_origin, dm_block_t data_dest, | |
921 | struct cell *cell, struct bio *bio) | |
922 | { | |
923 | int r; | |
924 | struct pool *pool = tc->pool; | |
925 | struct new_mapping *m = get_next_mapping(pool); | |
926 | ||
927 | INIT_LIST_HEAD(&m->list); | |
928 | m->prepared = 0; | |
929 | m->tc = tc; | |
930 | m->virt_block = virt_block; | |
931 | m->data_block = data_dest; | |
932 | m->cell = cell; | |
933 | m->err = 0; | |
934 | m->bio = NULL; | |
935 | ||
936 | ds_add_work(&pool->ds, &m->list); | |
937 | ||
938 | /* | |
939 | * IO to pool_dev remaps to the pool target's data_dev. | |
940 | * | |
941 | * If the whole block of data is being overwritten, we can issue the | |
942 | * bio immediately. Otherwise we use kcopyd to clone the data first. | |
943 | */ | |
944 | if (io_overwrites_block(pool, bio)) { | |
945 | m->bio = bio; | |
946 | save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); | |
947 | dm_get_mapinfo(bio)->ptr = m; | |
948 | remap_and_issue(tc, bio, data_dest); | |
949 | } else { | |
950 | struct dm_io_region from, to; | |
951 | ||
952 | from.bdev = tc->pool_dev->bdev; | |
953 | from.sector = data_origin * pool->sectors_per_block; | |
954 | from.count = pool->sectors_per_block; | |
955 | ||
956 | to.bdev = tc->pool_dev->bdev; | |
957 | to.sector = data_dest * pool->sectors_per_block; | |
958 | to.count = pool->sectors_per_block; | |
959 | ||
960 | r = dm_kcopyd_copy(pool->copier, &from, 1, &to, | |
961 | 0, copy_complete, m); | |
962 | if (r < 0) { | |
963 | mempool_free(m, pool->mapping_pool); | |
964 | DMERR("dm_kcopyd_copy() failed"); | |
965 | cell_error(cell); | |
966 | } | |
967 | } | |
968 | } | |
969 | ||
970 | static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, | |
971 | dm_block_t data_block, struct cell *cell, | |
972 | struct bio *bio) | |
973 | { | |
974 | struct pool *pool = tc->pool; | |
975 | struct new_mapping *m = get_next_mapping(pool); | |
976 | ||
977 | INIT_LIST_HEAD(&m->list); | |
978 | m->prepared = 0; | |
979 | m->tc = tc; | |
980 | m->virt_block = virt_block; | |
981 | m->data_block = data_block; | |
982 | m->cell = cell; | |
983 | m->err = 0; | |
984 | m->bio = NULL; | |
985 | ||
986 | /* | |
987 | * If the whole block of data is being overwritten or we are not | |
988 | * zeroing pre-existing data, we can issue the bio immediately. | |
989 | * Otherwise we use kcopyd to zero the data first. | |
990 | */ | |
991 | if (!pool->zero_new_blocks) | |
992 | process_prepared_mapping(m); | |
993 | ||
994 | else if (io_overwrites_block(pool, bio)) { | |
995 | m->bio = bio; | |
996 | save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); | |
997 | dm_get_mapinfo(bio)->ptr = m; | |
998 | remap_and_issue(tc, bio, data_block); | |
999 | ||
1000 | } else { | |
1001 | int r; | |
1002 | struct dm_io_region to; | |
1003 | ||
1004 | to.bdev = tc->pool_dev->bdev; | |
1005 | to.sector = data_block * pool->sectors_per_block; | |
1006 | to.count = pool->sectors_per_block; | |
1007 | ||
1008 | r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m); | |
1009 | if (r < 0) { | |
1010 | mempool_free(m, pool->mapping_pool); | |
1011 | DMERR("dm_kcopyd_zero() failed"); | |
1012 | cell_error(cell); | |
1013 | } | |
1014 | } | |
1015 | } | |
1016 | ||
1017 | static int alloc_data_block(struct thin_c *tc, dm_block_t *result) | |
1018 | { | |
1019 | int r; | |
1020 | dm_block_t free_blocks; | |
1021 | unsigned long flags; | |
1022 | struct pool *pool = tc->pool; | |
1023 | ||
1024 | r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); | |
1025 | if (r) | |
1026 | return r; | |
1027 | ||
1028 | if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) { | |
1029 | DMWARN("%s: reached low water mark, sending event.", | |
1030 | dm_device_name(pool->pool_md)); | |
1031 | spin_lock_irqsave(&pool->lock, flags); | |
1032 | pool->low_water_triggered = 1; | |
1033 | spin_unlock_irqrestore(&pool->lock, flags); | |
1034 | dm_table_event(pool->ti->table); | |
1035 | } | |
1036 | ||
1037 | if (!free_blocks) { | |
1038 | if (pool->no_free_space) | |
1039 | return -ENOSPC; | |
1040 | else { | |
1041 | /* | |
1042 | * Try to commit to see if that will free up some | |
1043 | * more space. | |
1044 | */ | |
1045 | r = dm_pool_commit_metadata(pool->pmd); | |
1046 | if (r) { | |
1047 | DMERR("%s: dm_pool_commit_metadata() failed, error = %d", | |
1048 | __func__, r); | |
1049 | return r; | |
1050 | } | |
1051 | ||
1052 | r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); | |
1053 | if (r) | |
1054 | return r; | |
1055 | ||
1056 | /* | |
1057 | * If we still have no space we set a flag to avoid | |
1058 | * doing all this checking and return -ENOSPC. | |
1059 | */ | |
1060 | if (!free_blocks) { | |
1061 | DMWARN("%s: no free space available.", | |
1062 | dm_device_name(pool->pool_md)); | |
1063 | spin_lock_irqsave(&pool->lock, flags); | |
1064 | pool->no_free_space = 1; | |
1065 | spin_unlock_irqrestore(&pool->lock, flags); | |
1066 | return -ENOSPC; | |
1067 | } | |
1068 | } | |
1069 | } | |
1070 | ||
1071 | r = dm_pool_alloc_data_block(pool->pmd, result); | |
1072 | if (r) | |
1073 | return r; | |
1074 | ||
1075 | return 0; | |
1076 | } | |
1077 | ||
1078 | /* | |
1079 | * If we have run out of space, queue bios until the device is | |
1080 | * resumed, presumably after having been reloaded with more space. | |
1081 | */ | |
1082 | static void retry_on_resume(struct bio *bio) | |
1083 | { | |
1084 | struct thin_c *tc = dm_get_mapinfo(bio)->ptr; | |
1085 | struct pool *pool = tc->pool; | |
1086 | unsigned long flags; | |
1087 | ||
1088 | spin_lock_irqsave(&pool->lock, flags); | |
1089 | bio_list_add(&pool->retry_on_resume_list, bio); | |
1090 | spin_unlock_irqrestore(&pool->lock, flags); | |
1091 | } | |
1092 | ||
1093 | static void no_space(struct cell *cell) | |
1094 | { | |
1095 | struct bio *bio; | |
1096 | struct bio_list bios; | |
1097 | ||
1098 | bio_list_init(&bios); | |
1099 | cell_release(cell, &bios); | |
1100 | ||
1101 | while ((bio = bio_list_pop(&bios))) | |
1102 | retry_on_resume(bio); | |
1103 | } | |
1104 | ||
1105 | static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block, | |
1106 | struct cell_key *key, | |
1107 | struct dm_thin_lookup_result *lookup_result, | |
1108 | struct cell *cell) | |
1109 | { | |
1110 | int r; | |
1111 | dm_block_t data_block; | |
1112 | ||
1113 | r = alloc_data_block(tc, &data_block); | |
1114 | switch (r) { | |
1115 | case 0: | |
1116 | schedule_copy(tc, block, lookup_result->block, | |
1117 | data_block, cell, bio); | |
1118 | break; | |
1119 | ||
1120 | case -ENOSPC: | |
1121 | no_space(cell); | |
1122 | break; | |
1123 | ||
1124 | default: | |
1125 | DMERR("%s: alloc_data_block() failed, error = %d", __func__, r); | |
1126 | cell_error(cell); | |
1127 | break; | |
1128 | } | |
1129 | } | |
1130 | ||
1131 | static void process_shared_bio(struct thin_c *tc, struct bio *bio, | |
1132 | dm_block_t block, | |
1133 | struct dm_thin_lookup_result *lookup_result) | |
1134 | { | |
1135 | struct cell *cell; | |
1136 | struct pool *pool = tc->pool; | |
1137 | struct cell_key key; | |
1138 | ||
1139 | /* | |
1140 | * If cell is already occupied, then sharing is already in the process | |
1141 | * of being broken so we have nothing further to do here. | |
1142 | */ | |
1143 | build_data_key(tc->td, lookup_result->block, &key); | |
1144 | if (bio_detain(pool->prison, &key, bio, &cell)) | |
1145 | return; | |
1146 | ||
1147 | if (bio_data_dir(bio) == WRITE) | |
1148 | break_sharing(tc, bio, block, &key, lookup_result, cell); | |
1149 | else { | |
1150 | struct endio_hook *h; | |
1151 | h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO); | |
1152 | ||
1153 | h->tc = tc; | |
1154 | h->entry = ds_inc(&pool->ds); | |
1155 | save_and_set_endio(bio, &h->saved_bi_end_io, shared_read_endio); | |
1156 | dm_get_mapinfo(bio)->ptr = h; | |
1157 | ||
1158 | cell_release_singleton(cell, bio); | |
1159 | remap_and_issue(tc, bio, lookup_result->block); | |
1160 | } | |
1161 | } | |
1162 | ||
1163 | static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block, | |
1164 | struct cell *cell) | |
1165 | { | |
1166 | int r; | |
1167 | dm_block_t data_block; | |
1168 | ||
1169 | /* | |
1170 | * Remap empty bios (flushes) immediately, without provisioning. | |
1171 | */ | |
1172 | if (!bio->bi_size) { | |
1173 | cell_release_singleton(cell, bio); | |
1174 | remap_and_issue(tc, bio, 0); | |
1175 | return; | |
1176 | } | |
1177 | ||
1178 | /* | |
1179 | * Fill read bios with zeroes and complete them immediately. | |
1180 | */ | |
1181 | if (bio_data_dir(bio) == READ) { | |
1182 | zero_fill_bio(bio); | |
1183 | cell_release_singleton(cell, bio); | |
1184 | bio_endio(bio, 0); | |
1185 | return; | |
1186 | } | |
1187 | ||
1188 | r = alloc_data_block(tc, &data_block); | |
1189 | switch (r) { | |
1190 | case 0: | |
1191 | schedule_zero(tc, block, data_block, cell, bio); | |
1192 | break; | |
1193 | ||
1194 | case -ENOSPC: | |
1195 | no_space(cell); | |
1196 | break; | |
1197 | ||
1198 | default: | |
1199 | DMERR("%s: alloc_data_block() failed, error = %d", __func__, r); | |
1200 | cell_error(cell); | |
1201 | break; | |
1202 | } | |
1203 | } | |
1204 | ||
1205 | static void process_bio(struct thin_c *tc, struct bio *bio) | |
1206 | { | |
1207 | int r; | |
1208 | dm_block_t block = get_bio_block(tc, bio); | |
1209 | struct cell *cell; | |
1210 | struct cell_key key; | |
1211 | struct dm_thin_lookup_result lookup_result; | |
1212 | ||
1213 | /* | |
1214 | * If cell is already occupied, then the block is already | |
1215 | * being provisioned so we have nothing further to do here. | |
1216 | */ | |
1217 | build_virtual_key(tc->td, block, &key); | |
1218 | if (bio_detain(tc->pool->prison, &key, bio, &cell)) | |
1219 | return; | |
1220 | ||
1221 | r = dm_thin_find_block(tc->td, block, 1, &lookup_result); | |
1222 | switch (r) { | |
1223 | case 0: | |
1224 | /* | |
1225 | * We can release this cell now. This thread is the only | |
1226 | * one that puts bios into a cell, and we know there were | |
1227 | * no preceding bios. | |
1228 | */ | |
1229 | /* | |
1230 | * TODO: this will probably have to change when discard goes | |
1231 | * back in. | |
1232 | */ | |
1233 | cell_release_singleton(cell, bio); | |
1234 | ||
1235 | if (lookup_result.shared) | |
1236 | process_shared_bio(tc, bio, block, &lookup_result); | |
1237 | else | |
1238 | remap_and_issue(tc, bio, lookup_result.block); | |
1239 | break; | |
1240 | ||
1241 | case -ENODATA: | |
1242 | provision_block(tc, bio, block, cell); | |
1243 | break; | |
1244 | ||
1245 | default: | |
1246 | DMERR("dm_thin_find_block() failed, error = %d", r); | |
1247 | bio_io_error(bio); | |
1248 | break; | |
1249 | } | |
1250 | } | |
1251 | ||
1252 | static void process_deferred_bios(struct pool *pool) | |
1253 | { | |
1254 | unsigned long flags; | |
1255 | struct bio *bio; | |
1256 | struct bio_list bios; | |
1257 | int r; | |
1258 | ||
1259 | bio_list_init(&bios); | |
1260 | ||
1261 | spin_lock_irqsave(&pool->lock, flags); | |
1262 | bio_list_merge(&bios, &pool->deferred_bios); | |
1263 | bio_list_init(&pool->deferred_bios); | |
1264 | spin_unlock_irqrestore(&pool->lock, flags); | |
1265 | ||
1266 | while ((bio = bio_list_pop(&bios))) { | |
1267 | struct thin_c *tc = dm_get_mapinfo(bio)->ptr; | |
1268 | /* | |
1269 | * If we've got no free new_mapping structs, and processing | |
1270 | * this bio might require one, we pause until there are some | |
1271 | * prepared mappings to process. | |
1272 | */ | |
1273 | if (ensure_next_mapping(pool)) { | |
1274 | spin_lock_irqsave(&pool->lock, flags); | |
1275 | bio_list_merge(&pool->deferred_bios, &bios); | |
1276 | spin_unlock_irqrestore(&pool->lock, flags); | |
1277 | ||
1278 | break; | |
1279 | } | |
1280 | process_bio(tc, bio); | |
1281 | } | |
1282 | ||
1283 | /* | |
1284 | * If there are any deferred flush bios, we must commit | |
1285 | * the metadata before issuing them. | |
1286 | */ | |
1287 | bio_list_init(&bios); | |
1288 | spin_lock_irqsave(&pool->lock, flags); | |
1289 | bio_list_merge(&bios, &pool->deferred_flush_bios); | |
1290 | bio_list_init(&pool->deferred_flush_bios); | |
1291 | spin_unlock_irqrestore(&pool->lock, flags); | |
1292 | ||
1293 | if (bio_list_empty(&bios)) | |
1294 | return; | |
1295 | ||
1296 | r = dm_pool_commit_metadata(pool->pmd); | |
1297 | if (r) { | |
1298 | DMERR("%s: dm_pool_commit_metadata() failed, error = %d", | |
1299 | __func__, r); | |
1300 | while ((bio = bio_list_pop(&bios))) | |
1301 | bio_io_error(bio); | |
1302 | return; | |
1303 | } | |
1304 | ||
1305 | while ((bio = bio_list_pop(&bios))) | |
1306 | generic_make_request(bio); | |
1307 | } | |
1308 | ||
1309 | static void do_worker(struct work_struct *ws) | |
1310 | { | |
1311 | struct pool *pool = container_of(ws, struct pool, worker); | |
1312 | ||
1313 | process_prepared_mappings(pool); | |
1314 | process_deferred_bios(pool); | |
1315 | } | |
1316 | ||
1317 | /*----------------------------------------------------------------*/ | |
1318 | ||
1319 | /* | |
1320 | * Mapping functions. | |
1321 | */ | |
1322 | ||
1323 | /* | |
1324 | * Called only while mapping a thin bio to hand it over to the workqueue. | |
1325 | */ | |
1326 | static void thin_defer_bio(struct thin_c *tc, struct bio *bio) | |
1327 | { | |
1328 | unsigned long flags; | |
1329 | struct pool *pool = tc->pool; | |
1330 | ||
1331 | spin_lock_irqsave(&pool->lock, flags); | |
1332 | bio_list_add(&pool->deferred_bios, bio); | |
1333 | spin_unlock_irqrestore(&pool->lock, flags); | |
1334 | ||
1335 | wake_worker(pool); | |
1336 | } | |
1337 | ||
1338 | /* | |
1339 | * Non-blocking function called from the thin target's map function. | |
1340 | */ | |
1341 | static int thin_bio_map(struct dm_target *ti, struct bio *bio, | |
1342 | union map_info *map_context) | |
1343 | { | |
1344 | int r; | |
1345 | struct thin_c *tc = ti->private; | |
1346 | dm_block_t block = get_bio_block(tc, bio); | |
1347 | struct dm_thin_device *td = tc->td; | |
1348 | struct dm_thin_lookup_result result; | |
1349 | ||
1350 | /* | |
1351 | * Save the thin context for easy access from the deferred bio later. | |
1352 | */ | |
1353 | map_context->ptr = tc; | |
1354 | ||
1355 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { | |
1356 | thin_defer_bio(tc, bio); | |
1357 | return DM_MAPIO_SUBMITTED; | |
1358 | } | |
1359 | ||
1360 | r = dm_thin_find_block(td, block, 0, &result); | |
1361 | ||
1362 | /* | |
1363 | * Note that we defer readahead too. | |
1364 | */ | |
1365 | switch (r) { | |
1366 | case 0: | |
1367 | if (unlikely(result.shared)) { | |
1368 | /* | |
1369 | * We have a race condition here between the | |
1370 | * result.shared value returned by the lookup and | |
1371 | * snapshot creation, which may cause new | |
1372 | * sharing. | |
1373 | * | |
1374 | * To avoid this always quiesce the origin before | |
1375 | * taking the snap. You want to do this anyway to | |
1376 | * ensure a consistent application view | |
1377 | * (i.e. lockfs). | |
1378 | * | |
1379 | * More distant ancestors are irrelevant. The | |
1380 | * shared flag will be set in their case. | |
1381 | */ | |
1382 | thin_defer_bio(tc, bio); | |
1383 | r = DM_MAPIO_SUBMITTED; | |
1384 | } else { | |
1385 | remap(tc, bio, result.block); | |
1386 | r = DM_MAPIO_REMAPPED; | |
1387 | } | |
1388 | break; | |
1389 | ||
1390 | case -ENODATA: | |
1391 | /* | |
1392 | * In future, the failed dm_thin_find_block above could | |
1393 | * provide the hint to load the metadata into cache. | |
1394 | */ | |
1395 | case -EWOULDBLOCK: | |
1396 | thin_defer_bio(tc, bio); | |
1397 | r = DM_MAPIO_SUBMITTED; | |
1398 | break; | |
1399 | } | |
1400 | ||
1401 | return r; | |
1402 | } | |
1403 | ||
1404 | static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits) | |
1405 | { | |
1406 | int r; | |
1407 | unsigned long flags; | |
1408 | struct pool_c *pt = container_of(cb, struct pool_c, callbacks); | |
1409 | ||
1410 | spin_lock_irqsave(&pt->pool->lock, flags); | |
1411 | r = !bio_list_empty(&pt->pool->retry_on_resume_list); | |
1412 | spin_unlock_irqrestore(&pt->pool->lock, flags); | |
1413 | ||
1414 | if (!r) { | |
1415 | struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); | |
1416 | r = bdi_congested(&q->backing_dev_info, bdi_bits); | |
1417 | } | |
1418 | ||
1419 | return r; | |
1420 | } | |
1421 | ||
1422 | static void __requeue_bios(struct pool *pool) | |
1423 | { | |
1424 | bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list); | |
1425 | bio_list_init(&pool->retry_on_resume_list); | |
1426 | } | |
1427 | ||
1428 | /*---------------------------------------------------------------- | |
1429 | * Binding of control targets to a pool object | |
1430 | *--------------------------------------------------------------*/ | |
1431 | static int bind_control_target(struct pool *pool, struct dm_target *ti) | |
1432 | { | |
1433 | struct pool_c *pt = ti->private; | |
1434 | ||
1435 | pool->ti = ti; | |
1436 | pool->low_water_blocks = pt->low_water_blocks; | |
1437 | pool->zero_new_blocks = pt->zero_new_blocks; | |
1438 | ||
1439 | return 0; | |
1440 | } | |
1441 | ||
1442 | static void unbind_control_target(struct pool *pool, struct dm_target *ti) | |
1443 | { | |
1444 | if (pool->ti == ti) | |
1445 | pool->ti = NULL; | |
1446 | } | |
1447 | ||
1448 | /*---------------------------------------------------------------- | |
1449 | * Pool creation | |
1450 | *--------------------------------------------------------------*/ | |
1451 | static void __pool_destroy(struct pool *pool) | |
1452 | { | |
1453 | __pool_table_remove(pool); | |
1454 | ||
1455 | if (dm_pool_metadata_close(pool->pmd) < 0) | |
1456 | DMWARN("%s: dm_pool_metadata_close() failed.", __func__); | |
1457 | ||
1458 | prison_destroy(pool->prison); | |
1459 | dm_kcopyd_client_destroy(pool->copier); | |
1460 | ||
1461 | if (pool->wq) | |
1462 | destroy_workqueue(pool->wq); | |
1463 | ||
1464 | if (pool->next_mapping) | |
1465 | mempool_free(pool->next_mapping, pool->mapping_pool); | |
1466 | mempool_destroy(pool->mapping_pool); | |
1467 | mempool_destroy(pool->endio_hook_pool); | |
1468 | kfree(pool); | |
1469 | } | |
1470 | ||
1471 | static struct pool *pool_create(struct mapped_device *pool_md, | |
1472 | struct block_device *metadata_dev, | |
1473 | unsigned long block_size, char **error) | |
1474 | { | |
1475 | int r; | |
1476 | void *err_p; | |
1477 | struct pool *pool; | |
1478 | struct dm_pool_metadata *pmd; | |
1479 | ||
1480 | pmd = dm_pool_metadata_open(metadata_dev, block_size); | |
1481 | if (IS_ERR(pmd)) { | |
1482 | *error = "Error creating metadata object"; | |
1483 | return (struct pool *)pmd; | |
1484 | } | |
1485 | ||
1486 | pool = kmalloc(sizeof(*pool), GFP_KERNEL); | |
1487 | if (!pool) { | |
1488 | *error = "Error allocating memory for pool"; | |
1489 | err_p = ERR_PTR(-ENOMEM); | |
1490 | goto bad_pool; | |
1491 | } | |
1492 | ||
1493 | pool->pmd = pmd; | |
1494 | pool->sectors_per_block = block_size; | |
1495 | pool->block_shift = ffs(block_size) - 1; | |
1496 | pool->offset_mask = block_size - 1; | |
1497 | pool->low_water_blocks = 0; | |
1498 | pool->zero_new_blocks = 1; | |
1499 | pool->prison = prison_create(PRISON_CELLS); | |
1500 | if (!pool->prison) { | |
1501 | *error = "Error creating pool's bio prison"; | |
1502 | err_p = ERR_PTR(-ENOMEM); | |
1503 | goto bad_prison; | |
1504 | } | |
1505 | ||
1506 | pool->copier = dm_kcopyd_client_create(); | |
1507 | if (IS_ERR(pool->copier)) { | |
1508 | r = PTR_ERR(pool->copier); | |
1509 | *error = "Error creating pool's kcopyd client"; | |
1510 | err_p = ERR_PTR(r); | |
1511 | goto bad_kcopyd_client; | |
1512 | } | |
1513 | ||
1514 | /* | |
1515 | * Create singlethreaded workqueue that will service all devices | |
1516 | * that use this metadata. | |
1517 | */ | |
1518 | pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); | |
1519 | if (!pool->wq) { | |
1520 | *error = "Error creating pool's workqueue"; | |
1521 | err_p = ERR_PTR(-ENOMEM); | |
1522 | goto bad_wq; | |
1523 | } | |
1524 | ||
1525 | INIT_WORK(&pool->worker, do_worker); | |
1526 | spin_lock_init(&pool->lock); | |
1527 | bio_list_init(&pool->deferred_bios); | |
1528 | bio_list_init(&pool->deferred_flush_bios); | |
1529 | INIT_LIST_HEAD(&pool->prepared_mappings); | |
1530 | pool->low_water_triggered = 0; | |
1531 | pool->no_free_space = 0; | |
1532 | bio_list_init(&pool->retry_on_resume_list); | |
1533 | ds_init(&pool->ds); | |
1534 | ||
1535 | pool->next_mapping = NULL; | |
1536 | pool->mapping_pool = | |
1537 | mempool_create_kmalloc_pool(MAPPING_POOL_SIZE, sizeof(struct new_mapping)); | |
1538 | if (!pool->mapping_pool) { | |
1539 | *error = "Error creating pool's mapping mempool"; | |
1540 | err_p = ERR_PTR(-ENOMEM); | |
1541 | goto bad_mapping_pool; | |
1542 | } | |
1543 | ||
1544 | pool->endio_hook_pool = | |
1545 | mempool_create_kmalloc_pool(ENDIO_HOOK_POOL_SIZE, sizeof(struct endio_hook)); | |
1546 | if (!pool->endio_hook_pool) { | |
1547 | *error = "Error creating pool's endio_hook mempool"; | |
1548 | err_p = ERR_PTR(-ENOMEM); | |
1549 | goto bad_endio_hook_pool; | |
1550 | } | |
1551 | pool->ref_count = 1; | |
1552 | pool->pool_md = pool_md; | |
1553 | pool->md_dev = metadata_dev; | |
1554 | __pool_table_insert(pool); | |
1555 | ||
1556 | return pool; | |
1557 | ||
1558 | bad_endio_hook_pool: | |
1559 | mempool_destroy(pool->mapping_pool); | |
1560 | bad_mapping_pool: | |
1561 | destroy_workqueue(pool->wq); | |
1562 | bad_wq: | |
1563 | dm_kcopyd_client_destroy(pool->copier); | |
1564 | bad_kcopyd_client: | |
1565 | prison_destroy(pool->prison); | |
1566 | bad_prison: | |
1567 | kfree(pool); | |
1568 | bad_pool: | |
1569 | if (dm_pool_metadata_close(pmd)) | |
1570 | DMWARN("%s: dm_pool_metadata_close() failed.", __func__); | |
1571 | ||
1572 | return err_p; | |
1573 | } | |
1574 | ||
1575 | static void __pool_inc(struct pool *pool) | |
1576 | { | |
1577 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); | |
1578 | pool->ref_count++; | |
1579 | } | |
1580 | ||
1581 | static void __pool_dec(struct pool *pool) | |
1582 | { | |
1583 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); | |
1584 | BUG_ON(!pool->ref_count); | |
1585 | if (!--pool->ref_count) | |
1586 | __pool_destroy(pool); | |
1587 | } | |
1588 | ||
1589 | static struct pool *__pool_find(struct mapped_device *pool_md, | |
1590 | struct block_device *metadata_dev, | |
1591 | unsigned long block_size, char **error) | |
1592 | { | |
1593 | struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev); | |
1594 | ||
1595 | if (pool) { | |
1596 | if (pool->pool_md != pool_md) | |
1597 | return ERR_PTR(-EBUSY); | |
1598 | __pool_inc(pool); | |
1599 | ||
1600 | } else { | |
1601 | pool = __pool_table_lookup(pool_md); | |
1602 | if (pool) { | |
1603 | if (pool->md_dev != metadata_dev) | |
1604 | return ERR_PTR(-EINVAL); | |
1605 | __pool_inc(pool); | |
1606 | ||
1607 | } else | |
1608 | pool = pool_create(pool_md, metadata_dev, block_size, error); | |
1609 | } | |
1610 | ||
1611 | return pool; | |
1612 | } | |
1613 | ||
1614 | /*---------------------------------------------------------------- | |
1615 | * Pool target methods | |
1616 | *--------------------------------------------------------------*/ | |
1617 | static void pool_dtr(struct dm_target *ti) | |
1618 | { | |
1619 | struct pool_c *pt = ti->private; | |
1620 | ||
1621 | mutex_lock(&dm_thin_pool_table.mutex); | |
1622 | ||
1623 | unbind_control_target(pt->pool, ti); | |
1624 | __pool_dec(pt->pool); | |
1625 | dm_put_device(ti, pt->metadata_dev); | |
1626 | dm_put_device(ti, pt->data_dev); | |
1627 | kfree(pt); | |
1628 | ||
1629 | mutex_unlock(&dm_thin_pool_table.mutex); | |
1630 | } | |
1631 | ||
1632 | struct pool_features { | |
1633 | unsigned zero_new_blocks:1; | |
1634 | }; | |
1635 | ||
1636 | static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf, | |
1637 | struct dm_target *ti) | |
1638 | { | |
1639 | int r; | |
1640 | unsigned argc; | |
1641 | const char *arg_name; | |
1642 | ||
1643 | static struct dm_arg _args[] = { | |
1644 | {0, 1, "Invalid number of pool feature arguments"}, | |
1645 | }; | |
1646 | ||
1647 | /* | |
1648 | * No feature arguments supplied. | |
1649 | */ | |
1650 | if (!as->argc) | |
1651 | return 0; | |
1652 | ||
1653 | r = dm_read_arg_group(_args, as, &argc, &ti->error); | |
1654 | if (r) | |
1655 | return -EINVAL; | |
1656 | ||
1657 | while (argc && !r) { | |
1658 | arg_name = dm_shift_arg(as); | |
1659 | argc--; | |
1660 | ||
1661 | if (!strcasecmp(arg_name, "skip_block_zeroing")) { | |
1662 | pf->zero_new_blocks = 0; | |
1663 | continue; | |
1664 | } | |
1665 | ||
1666 | ti->error = "Unrecognised pool feature requested"; | |
1667 | r = -EINVAL; | |
1668 | } | |
1669 | ||
1670 | return r; | |
1671 | } | |
1672 | ||
1673 | /* | |
1674 | * thin-pool <metadata dev> <data dev> | |
1675 | * <data block size (sectors)> | |
1676 | * <low water mark (blocks)> | |
1677 | * [<#feature args> [<arg>]*] | |
1678 | * | |
1679 | * Optional feature arguments are: | |
1680 | * skip_block_zeroing: skips the zeroing of newly-provisioned blocks. | |
1681 | */ | |
1682 | static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
1683 | { | |
1684 | int r; | |
1685 | struct pool_c *pt; | |
1686 | struct pool *pool; | |
1687 | struct pool_features pf; | |
1688 | struct dm_arg_set as; | |
1689 | struct dm_dev *data_dev; | |
1690 | unsigned long block_size; | |
1691 | dm_block_t low_water_blocks; | |
1692 | struct dm_dev *metadata_dev; | |
1693 | sector_t metadata_dev_size; | |
1694 | ||
1695 | /* | |
1696 | * FIXME Remove validation from scope of lock. | |
1697 | */ | |
1698 | mutex_lock(&dm_thin_pool_table.mutex); | |
1699 | ||
1700 | if (argc < 4) { | |
1701 | ti->error = "Invalid argument count"; | |
1702 | r = -EINVAL; | |
1703 | goto out_unlock; | |
1704 | } | |
1705 | as.argc = argc; | |
1706 | as.argv = argv; | |
1707 | ||
1708 | r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev); | |
1709 | if (r) { | |
1710 | ti->error = "Error opening metadata block device"; | |
1711 | goto out_unlock; | |
1712 | } | |
1713 | ||
1714 | metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT; | |
1715 | if (metadata_dev_size > METADATA_DEV_MAX_SECTORS) { | |
1716 | ti->error = "Metadata device is too large"; | |
1717 | r = -EINVAL; | |
1718 | goto out_metadata; | |
1719 | } | |
1720 | ||
1721 | r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev); | |
1722 | if (r) { | |
1723 | ti->error = "Error getting data device"; | |
1724 | goto out_metadata; | |
1725 | } | |
1726 | ||
1727 | if (kstrtoul(argv[2], 10, &block_size) || !block_size || | |
1728 | block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || | |
1729 | block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || | |
1730 | !is_power_of_2(block_size)) { | |
1731 | ti->error = "Invalid block size"; | |
1732 | r = -EINVAL; | |
1733 | goto out; | |
1734 | } | |
1735 | ||
1736 | if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) { | |
1737 | ti->error = "Invalid low water mark"; | |
1738 | r = -EINVAL; | |
1739 | goto out; | |
1740 | } | |
1741 | ||
1742 | /* | |
1743 | * Set default pool features. | |
1744 | */ | |
1745 | memset(&pf, 0, sizeof(pf)); | |
1746 | pf.zero_new_blocks = 1; | |
1747 | ||
1748 | dm_consume_args(&as, 4); | |
1749 | r = parse_pool_features(&as, &pf, ti); | |
1750 | if (r) | |
1751 | goto out; | |
1752 | ||
1753 | pt = kzalloc(sizeof(*pt), GFP_KERNEL); | |
1754 | if (!pt) { | |
1755 | r = -ENOMEM; | |
1756 | goto out; | |
1757 | } | |
1758 | ||
1759 | pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, | |
1760 | block_size, &ti->error); | |
1761 | if (IS_ERR(pool)) { | |
1762 | r = PTR_ERR(pool); | |
1763 | goto out_free_pt; | |
1764 | } | |
1765 | ||
1766 | pt->pool = pool; | |
1767 | pt->ti = ti; | |
1768 | pt->metadata_dev = metadata_dev; | |
1769 | pt->data_dev = data_dev; | |
1770 | pt->low_water_blocks = low_water_blocks; | |
1771 | pt->zero_new_blocks = pf.zero_new_blocks; | |
1772 | ti->num_flush_requests = 1; | |
1773 | ti->num_discard_requests = 0; | |
1774 | ti->private = pt; | |
1775 | ||
1776 | pt->callbacks.congested_fn = pool_is_congested; | |
1777 | dm_table_add_target_callbacks(ti->table, &pt->callbacks); | |
1778 | ||
1779 | mutex_unlock(&dm_thin_pool_table.mutex); | |
1780 | ||
1781 | return 0; | |
1782 | ||
1783 | out_free_pt: | |
1784 | kfree(pt); | |
1785 | out: | |
1786 | dm_put_device(ti, data_dev); | |
1787 | out_metadata: | |
1788 | dm_put_device(ti, metadata_dev); | |
1789 | out_unlock: | |
1790 | mutex_unlock(&dm_thin_pool_table.mutex); | |
1791 | ||
1792 | return r; | |
1793 | } | |
1794 | ||
1795 | static int pool_map(struct dm_target *ti, struct bio *bio, | |
1796 | union map_info *map_context) | |
1797 | { | |
1798 | int r; | |
1799 | struct pool_c *pt = ti->private; | |
1800 | struct pool *pool = pt->pool; | |
1801 | unsigned long flags; | |
1802 | ||
1803 | /* | |
1804 | * As this is a singleton target, ti->begin is always zero. | |
1805 | */ | |
1806 | spin_lock_irqsave(&pool->lock, flags); | |
1807 | bio->bi_bdev = pt->data_dev->bdev; | |
1808 | r = DM_MAPIO_REMAPPED; | |
1809 | spin_unlock_irqrestore(&pool->lock, flags); | |
1810 | ||
1811 | return r; | |
1812 | } | |
1813 | ||
1814 | /* | |
1815 | * Retrieves the number of blocks of the data device from | |
1816 | * the superblock and compares it to the actual device size, | |
1817 | * thus resizing the data device in case it has grown. | |
1818 | * | |
1819 | * This both copes with opening preallocated data devices in the ctr | |
1820 | * being followed by a resume | |
1821 | * -and- | |
1822 | * calling the resume method individually after userspace has | |
1823 | * grown the data device in reaction to a table event. | |
1824 | */ | |
1825 | static int pool_preresume(struct dm_target *ti) | |
1826 | { | |
1827 | int r; | |
1828 | struct pool_c *pt = ti->private; | |
1829 | struct pool *pool = pt->pool; | |
1830 | dm_block_t data_size, sb_data_size; | |
1831 | ||
1832 | /* | |
1833 | * Take control of the pool object. | |
1834 | */ | |
1835 | r = bind_control_target(pool, ti); | |
1836 | if (r) | |
1837 | return r; | |
1838 | ||
1839 | data_size = ti->len >> pool->block_shift; | |
1840 | r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size); | |
1841 | if (r) { | |
1842 | DMERR("failed to retrieve data device size"); | |
1843 | return r; | |
1844 | } | |
1845 | ||
1846 | if (data_size < sb_data_size) { | |
1847 | DMERR("pool target too small, is %llu blocks (expected %llu)", | |
1848 | data_size, sb_data_size); | |
1849 | return -EINVAL; | |
1850 | ||
1851 | } else if (data_size > sb_data_size) { | |
1852 | r = dm_pool_resize_data_dev(pool->pmd, data_size); | |
1853 | if (r) { | |
1854 | DMERR("failed to resize data device"); | |
1855 | return r; | |
1856 | } | |
1857 | ||
1858 | r = dm_pool_commit_metadata(pool->pmd); | |
1859 | if (r) { | |
1860 | DMERR("%s: dm_pool_commit_metadata() failed, error = %d", | |
1861 | __func__, r); | |
1862 | return r; | |
1863 | } | |
1864 | } | |
1865 | ||
1866 | return 0; | |
1867 | } | |
1868 | ||
1869 | static void pool_resume(struct dm_target *ti) | |
1870 | { | |
1871 | struct pool_c *pt = ti->private; | |
1872 | struct pool *pool = pt->pool; | |
1873 | unsigned long flags; | |
1874 | ||
1875 | spin_lock_irqsave(&pool->lock, flags); | |
1876 | pool->low_water_triggered = 0; | |
1877 | pool->no_free_space = 0; | |
1878 | __requeue_bios(pool); | |
1879 | spin_unlock_irqrestore(&pool->lock, flags); | |
1880 | ||
1881 | wake_worker(pool); | |
1882 | } | |
1883 | ||
1884 | static void pool_postsuspend(struct dm_target *ti) | |
1885 | { | |
1886 | int r; | |
1887 | struct pool_c *pt = ti->private; | |
1888 | struct pool *pool = pt->pool; | |
1889 | ||
1890 | flush_workqueue(pool->wq); | |
1891 | ||
1892 | r = dm_pool_commit_metadata(pool->pmd); | |
1893 | if (r < 0) { | |
1894 | DMERR("%s: dm_pool_commit_metadata() failed, error = %d", | |
1895 | __func__, r); | |
1896 | /* FIXME: invalidate device? error the next FUA or FLUSH bio ?*/ | |
1897 | } | |
1898 | } | |
1899 | ||
1900 | static int check_arg_count(unsigned argc, unsigned args_required) | |
1901 | { | |
1902 | if (argc != args_required) { | |
1903 | DMWARN("Message received with %u arguments instead of %u.", | |
1904 | argc, args_required); | |
1905 | return -EINVAL; | |
1906 | } | |
1907 | ||
1908 | return 0; | |
1909 | } | |
1910 | ||
1911 | static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning) | |
1912 | { | |
1913 | if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) && | |
1914 | *dev_id <= MAX_DEV_ID) | |
1915 | return 0; | |
1916 | ||
1917 | if (warning) | |
1918 | DMWARN("Message received with invalid device id: %s", arg); | |
1919 | ||
1920 | return -EINVAL; | |
1921 | } | |
1922 | ||
1923 | static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool) | |
1924 | { | |
1925 | dm_thin_id dev_id; | |
1926 | int r; | |
1927 | ||
1928 | r = check_arg_count(argc, 2); | |
1929 | if (r) | |
1930 | return r; | |
1931 | ||
1932 | r = read_dev_id(argv[1], &dev_id, 1); | |
1933 | if (r) | |
1934 | return r; | |
1935 | ||
1936 | r = dm_pool_create_thin(pool->pmd, dev_id); | |
1937 | if (r) { | |
1938 | DMWARN("Creation of new thinly-provisioned device with id %s failed.", | |
1939 | argv[1]); | |
1940 | return r; | |
1941 | } | |
1942 | ||
1943 | return 0; | |
1944 | } | |
1945 | ||
1946 | static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool) | |
1947 | { | |
1948 | dm_thin_id dev_id; | |
1949 | dm_thin_id origin_dev_id; | |
1950 | int r; | |
1951 | ||
1952 | r = check_arg_count(argc, 3); | |
1953 | if (r) | |
1954 | return r; | |
1955 | ||
1956 | r = read_dev_id(argv[1], &dev_id, 1); | |
1957 | if (r) | |
1958 | return r; | |
1959 | ||
1960 | r = read_dev_id(argv[2], &origin_dev_id, 1); | |
1961 | if (r) | |
1962 | return r; | |
1963 | ||
1964 | r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id); | |
1965 | if (r) { | |
1966 | DMWARN("Creation of new snapshot %s of device %s failed.", | |
1967 | argv[1], argv[2]); | |
1968 | return r; | |
1969 | } | |
1970 | ||
1971 | return 0; | |
1972 | } | |
1973 | ||
1974 | static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool) | |
1975 | { | |
1976 | dm_thin_id dev_id; | |
1977 | int r; | |
1978 | ||
1979 | r = check_arg_count(argc, 2); | |
1980 | if (r) | |
1981 | return r; | |
1982 | ||
1983 | r = read_dev_id(argv[1], &dev_id, 1); | |
1984 | if (r) | |
1985 | return r; | |
1986 | ||
1987 | r = dm_pool_delete_thin_device(pool->pmd, dev_id); | |
1988 | if (r) | |
1989 | DMWARN("Deletion of thin device %s failed.", argv[1]); | |
1990 | ||
1991 | return r; | |
1992 | } | |
1993 | ||
1994 | static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool) | |
1995 | { | |
1996 | dm_thin_id old_id, new_id; | |
1997 | int r; | |
1998 | ||
1999 | r = check_arg_count(argc, 3); | |
2000 | if (r) | |
2001 | return r; | |
2002 | ||
2003 | if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) { | |
2004 | DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]); | |
2005 | return -EINVAL; | |
2006 | } | |
2007 | ||
2008 | if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) { | |
2009 | DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]); | |
2010 | return -EINVAL; | |
2011 | } | |
2012 | ||
2013 | r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id); | |
2014 | if (r) { | |
2015 | DMWARN("Failed to change transaction id from %s to %s.", | |
2016 | argv[1], argv[2]); | |
2017 | return r; | |
2018 | } | |
2019 | ||
2020 | return 0; | |
2021 | } | |
2022 | ||
2023 | /* | |
2024 | * Messages supported: | |
2025 | * create_thin <dev_id> | |
2026 | * create_snap <dev_id> <origin_id> | |
2027 | * delete <dev_id> | |
2028 | * trim <dev_id> <new_size_in_sectors> | |
2029 | * set_transaction_id <current_trans_id> <new_trans_id> | |
2030 | */ | |
2031 | static int pool_message(struct dm_target *ti, unsigned argc, char **argv) | |
2032 | { | |
2033 | int r = -EINVAL; | |
2034 | struct pool_c *pt = ti->private; | |
2035 | struct pool *pool = pt->pool; | |
2036 | ||
2037 | if (!strcasecmp(argv[0], "create_thin")) | |
2038 | r = process_create_thin_mesg(argc, argv, pool); | |
2039 | ||
2040 | else if (!strcasecmp(argv[0], "create_snap")) | |
2041 | r = process_create_snap_mesg(argc, argv, pool); | |
2042 | ||
2043 | else if (!strcasecmp(argv[0], "delete")) | |
2044 | r = process_delete_mesg(argc, argv, pool); | |
2045 | ||
2046 | else if (!strcasecmp(argv[0], "set_transaction_id")) | |
2047 | r = process_set_transaction_id_mesg(argc, argv, pool); | |
2048 | ||
2049 | else | |
2050 | DMWARN("Unrecognised thin pool target message received: %s", argv[0]); | |
2051 | ||
2052 | if (!r) { | |
2053 | r = dm_pool_commit_metadata(pool->pmd); | |
2054 | if (r) | |
2055 | DMERR("%s message: dm_pool_commit_metadata() failed, error = %d", | |
2056 | argv[0], r); | |
2057 | } | |
2058 | ||
2059 | return r; | |
2060 | } | |
2061 | ||
2062 | /* | |
2063 | * Status line is: | |
2064 | * <transaction id> <used metadata sectors>/<total metadata sectors> | |
2065 | * <used data sectors>/<total data sectors> <held metadata root> | |
2066 | */ | |
2067 | static int pool_status(struct dm_target *ti, status_type_t type, | |
2068 | char *result, unsigned maxlen) | |
2069 | { | |
2070 | int r; | |
2071 | unsigned sz = 0; | |
2072 | uint64_t transaction_id; | |
2073 | dm_block_t nr_free_blocks_data; | |
2074 | dm_block_t nr_free_blocks_metadata; | |
2075 | dm_block_t nr_blocks_data; | |
2076 | dm_block_t nr_blocks_metadata; | |
2077 | dm_block_t held_root; | |
2078 | char buf[BDEVNAME_SIZE]; | |
2079 | char buf2[BDEVNAME_SIZE]; | |
2080 | struct pool_c *pt = ti->private; | |
2081 | struct pool *pool = pt->pool; | |
2082 | ||
2083 | switch (type) { | |
2084 | case STATUSTYPE_INFO: | |
2085 | r = dm_pool_get_metadata_transaction_id(pool->pmd, | |
2086 | &transaction_id); | |
2087 | if (r) | |
2088 | return r; | |
2089 | ||
2090 | r = dm_pool_get_free_metadata_block_count(pool->pmd, | |
2091 | &nr_free_blocks_metadata); | |
2092 | if (r) | |
2093 | return r; | |
2094 | ||
2095 | r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata); | |
2096 | if (r) | |
2097 | return r; | |
2098 | ||
2099 | r = dm_pool_get_free_block_count(pool->pmd, | |
2100 | &nr_free_blocks_data); | |
2101 | if (r) | |
2102 | return r; | |
2103 | ||
2104 | r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data); | |
2105 | if (r) | |
2106 | return r; | |
2107 | ||
2108 | r = dm_pool_get_held_metadata_root(pool->pmd, &held_root); | |
2109 | if (r) | |
2110 | return r; | |
2111 | ||
2112 | DMEMIT("%llu %llu/%llu %llu/%llu ", | |
2113 | (unsigned long long)transaction_id, | |
2114 | (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), | |
2115 | (unsigned long long)nr_blocks_metadata, | |
2116 | (unsigned long long)(nr_blocks_data - nr_free_blocks_data), | |
2117 | (unsigned long long)nr_blocks_data); | |
2118 | ||
2119 | if (held_root) | |
2120 | DMEMIT("%llu", held_root); | |
2121 | else | |
2122 | DMEMIT("-"); | |
2123 | ||
2124 | break; | |
2125 | ||
2126 | case STATUSTYPE_TABLE: | |
2127 | DMEMIT("%s %s %lu %llu ", | |
2128 | format_dev_t(buf, pt->metadata_dev->bdev->bd_dev), | |
2129 | format_dev_t(buf2, pt->data_dev->bdev->bd_dev), | |
2130 | (unsigned long)pool->sectors_per_block, | |
2131 | (unsigned long long)pt->low_water_blocks); | |
2132 | ||
2133 | DMEMIT("%u ", !pool->zero_new_blocks); | |
2134 | ||
2135 | if (!pool->zero_new_blocks) | |
2136 | DMEMIT("skip_block_zeroing "); | |
2137 | break; | |
2138 | } | |
2139 | ||
2140 | return 0; | |
2141 | } | |
2142 | ||
2143 | static int pool_iterate_devices(struct dm_target *ti, | |
2144 | iterate_devices_callout_fn fn, void *data) | |
2145 | { | |
2146 | struct pool_c *pt = ti->private; | |
2147 | ||
2148 | return fn(ti, pt->data_dev, 0, ti->len, data); | |
2149 | } | |
2150 | ||
2151 | static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm, | |
2152 | struct bio_vec *biovec, int max_size) | |
2153 | { | |
2154 | struct pool_c *pt = ti->private; | |
2155 | struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); | |
2156 | ||
2157 | if (!q->merge_bvec_fn) | |
2158 | return max_size; | |
2159 | ||
2160 | bvm->bi_bdev = pt->data_dev->bdev; | |
2161 | ||
2162 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
2163 | } | |
2164 | ||
2165 | static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
2166 | { | |
2167 | struct pool_c *pt = ti->private; | |
2168 | struct pool *pool = pt->pool; | |
2169 | ||
2170 | blk_limits_io_min(limits, 0); | |
2171 | blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); | |
2172 | } | |
2173 | ||
2174 | static struct target_type pool_target = { | |
2175 | .name = "thin-pool", | |
2176 | .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | | |
2177 | DM_TARGET_IMMUTABLE, | |
2178 | .version = {1, 0, 0}, | |
2179 | .module = THIS_MODULE, | |
2180 | .ctr = pool_ctr, | |
2181 | .dtr = pool_dtr, | |
2182 | .map = pool_map, | |
2183 | .postsuspend = pool_postsuspend, | |
2184 | .preresume = pool_preresume, | |
2185 | .resume = pool_resume, | |
2186 | .message = pool_message, | |
2187 | .status = pool_status, | |
2188 | .merge = pool_merge, | |
2189 | .iterate_devices = pool_iterate_devices, | |
2190 | .io_hints = pool_io_hints, | |
2191 | }; | |
2192 | ||
2193 | /*---------------------------------------------------------------- | |
2194 | * Thin target methods | |
2195 | *--------------------------------------------------------------*/ | |
2196 | static void thin_dtr(struct dm_target *ti) | |
2197 | { | |
2198 | struct thin_c *tc = ti->private; | |
2199 | ||
2200 | mutex_lock(&dm_thin_pool_table.mutex); | |
2201 | ||
2202 | __pool_dec(tc->pool); | |
2203 | dm_pool_close_thin_device(tc->td); | |
2204 | dm_put_device(ti, tc->pool_dev); | |
2205 | kfree(tc); | |
2206 | ||
2207 | mutex_unlock(&dm_thin_pool_table.mutex); | |
2208 | } | |
2209 | ||
2210 | /* | |
2211 | * Thin target parameters: | |
2212 | * | |
2213 | * <pool_dev> <dev_id> | |
2214 | * | |
2215 | * pool_dev: the path to the pool (eg, /dev/mapper/my_pool) | |
2216 | * dev_id: the internal device identifier | |
2217 | */ | |
2218 | static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
2219 | { | |
2220 | int r; | |
2221 | struct thin_c *tc; | |
2222 | struct dm_dev *pool_dev; | |
2223 | struct mapped_device *pool_md; | |
2224 | ||
2225 | mutex_lock(&dm_thin_pool_table.mutex); | |
2226 | ||
2227 | if (argc != 2) { | |
2228 | ti->error = "Invalid argument count"; | |
2229 | r = -EINVAL; | |
2230 | goto out_unlock; | |
2231 | } | |
2232 | ||
2233 | tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL); | |
2234 | if (!tc) { | |
2235 | ti->error = "Out of memory"; | |
2236 | r = -ENOMEM; | |
2237 | goto out_unlock; | |
2238 | } | |
2239 | ||
2240 | r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev); | |
2241 | if (r) { | |
2242 | ti->error = "Error opening pool device"; | |
2243 | goto bad_pool_dev; | |
2244 | } | |
2245 | tc->pool_dev = pool_dev; | |
2246 | ||
2247 | if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) { | |
2248 | ti->error = "Invalid device id"; | |
2249 | r = -EINVAL; | |
2250 | goto bad_common; | |
2251 | } | |
2252 | ||
2253 | pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev); | |
2254 | if (!pool_md) { | |
2255 | ti->error = "Couldn't get pool mapped device"; | |
2256 | r = -EINVAL; | |
2257 | goto bad_common; | |
2258 | } | |
2259 | ||
2260 | tc->pool = __pool_table_lookup(pool_md); | |
2261 | if (!tc->pool) { | |
2262 | ti->error = "Couldn't find pool object"; | |
2263 | r = -EINVAL; | |
2264 | goto bad_pool_lookup; | |
2265 | } | |
2266 | __pool_inc(tc->pool); | |
2267 | ||
2268 | r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td); | |
2269 | if (r) { | |
2270 | ti->error = "Couldn't open thin internal device"; | |
2271 | goto bad_thin_open; | |
2272 | } | |
2273 | ||
2274 | ti->split_io = tc->pool->sectors_per_block; | |
2275 | ti->num_flush_requests = 1; | |
2276 | ti->num_discard_requests = 0; | |
2277 | ti->discards_supported = 0; | |
2278 | ||
2279 | dm_put(pool_md); | |
2280 | ||
2281 | mutex_unlock(&dm_thin_pool_table.mutex); | |
2282 | ||
2283 | return 0; | |
2284 | ||
2285 | bad_thin_open: | |
2286 | __pool_dec(tc->pool); | |
2287 | bad_pool_lookup: | |
2288 | dm_put(pool_md); | |
2289 | bad_common: | |
2290 | dm_put_device(ti, tc->pool_dev); | |
2291 | bad_pool_dev: | |
2292 | kfree(tc); | |
2293 | out_unlock: | |
2294 | mutex_unlock(&dm_thin_pool_table.mutex); | |
2295 | ||
2296 | return r; | |
2297 | } | |
2298 | ||
2299 | static int thin_map(struct dm_target *ti, struct bio *bio, | |
2300 | union map_info *map_context) | |
2301 | { | |
2302 | bio->bi_sector -= ti->begin; | |
2303 | ||
2304 | return thin_bio_map(ti, bio, map_context); | |
2305 | } | |
2306 | ||
2307 | static void thin_postsuspend(struct dm_target *ti) | |
2308 | { | |
2309 | if (dm_noflush_suspending(ti)) | |
2310 | requeue_io((struct thin_c *)ti->private); | |
2311 | } | |
2312 | ||
2313 | /* | |
2314 | * <nr mapped sectors> <highest mapped sector> | |
2315 | */ | |
2316 | static int thin_status(struct dm_target *ti, status_type_t type, | |
2317 | char *result, unsigned maxlen) | |
2318 | { | |
2319 | int r; | |
2320 | ssize_t sz = 0; | |
2321 | dm_block_t mapped, highest; | |
2322 | char buf[BDEVNAME_SIZE]; | |
2323 | struct thin_c *tc = ti->private; | |
2324 | ||
2325 | if (!tc->td) | |
2326 | DMEMIT("-"); | |
2327 | else { | |
2328 | switch (type) { | |
2329 | case STATUSTYPE_INFO: | |
2330 | r = dm_thin_get_mapped_count(tc->td, &mapped); | |
2331 | if (r) | |
2332 | return r; | |
2333 | ||
2334 | r = dm_thin_get_highest_mapped_block(tc->td, &highest); | |
2335 | if (r < 0) | |
2336 | return r; | |
2337 | ||
2338 | DMEMIT("%llu ", mapped * tc->pool->sectors_per_block); | |
2339 | if (r) | |
2340 | DMEMIT("%llu", ((highest + 1) * | |
2341 | tc->pool->sectors_per_block) - 1); | |
2342 | else | |
2343 | DMEMIT("-"); | |
2344 | break; | |
2345 | ||
2346 | case STATUSTYPE_TABLE: | |
2347 | DMEMIT("%s %lu", | |
2348 | format_dev_t(buf, tc->pool_dev->bdev->bd_dev), | |
2349 | (unsigned long) tc->dev_id); | |
2350 | break; | |
2351 | } | |
2352 | } | |
2353 | ||
2354 | return 0; | |
2355 | } | |
2356 | ||
2357 | static int thin_iterate_devices(struct dm_target *ti, | |
2358 | iterate_devices_callout_fn fn, void *data) | |
2359 | { | |
2360 | dm_block_t blocks; | |
2361 | struct thin_c *tc = ti->private; | |
2362 | ||
2363 | /* | |
2364 | * We can't call dm_pool_get_data_dev_size() since that blocks. So | |
2365 | * we follow a more convoluted path through to the pool's target. | |
2366 | */ | |
2367 | if (!tc->pool->ti) | |
2368 | return 0; /* nothing is bound */ | |
2369 | ||
2370 | blocks = tc->pool->ti->len >> tc->pool->block_shift; | |
2371 | if (blocks) | |
2372 | return fn(ti, tc->pool_dev, 0, tc->pool->sectors_per_block * blocks, data); | |
2373 | ||
2374 | return 0; | |
2375 | } | |
2376 | ||
2377 | static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
2378 | { | |
2379 | struct thin_c *tc = ti->private; | |
2380 | ||
2381 | blk_limits_io_min(limits, 0); | |
2382 | blk_limits_io_opt(limits, tc->pool->sectors_per_block << SECTOR_SHIFT); | |
2383 | } | |
2384 | ||
2385 | static struct target_type thin_target = { | |
2386 | .name = "thin", | |
2387 | .version = {1, 0, 0}, | |
2388 | .module = THIS_MODULE, | |
2389 | .ctr = thin_ctr, | |
2390 | .dtr = thin_dtr, | |
2391 | .map = thin_map, | |
2392 | .postsuspend = thin_postsuspend, | |
2393 | .status = thin_status, | |
2394 | .iterate_devices = thin_iterate_devices, | |
2395 | .io_hints = thin_io_hints, | |
2396 | }; | |
2397 | ||
2398 | /*----------------------------------------------------------------*/ | |
2399 | ||
2400 | static int __init dm_thin_init(void) | |
2401 | { | |
2402 | int r; | |
2403 | ||
2404 | pool_table_init(); | |
2405 | ||
2406 | r = dm_register_target(&thin_target); | |
2407 | if (r) | |
2408 | return r; | |
2409 | ||
2410 | r = dm_register_target(&pool_target); | |
2411 | if (r) | |
2412 | dm_unregister_target(&thin_target); | |
2413 | ||
2414 | return r; | |
2415 | } | |
2416 | ||
2417 | static void dm_thin_exit(void) | |
2418 | { | |
2419 | dm_unregister_target(&thin_target); | |
2420 | dm_unregister_target(&pool_target); | |
2421 | } | |
2422 | ||
2423 | module_init(dm_thin_init); | |
2424 | module_exit(dm_thin_exit); | |
2425 | ||
2426 | MODULE_DESCRIPTION(DM_NAME "device-mapper thin provisioning target"); | |
2427 | MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); | |
2428 | MODULE_LICENSE("GPL"); |