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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 1024
23#define DEFERRED_SET_SIZE 64
24#define MAPPING_POOL_SIZE 1024
25#define PRISON_CELLS 1024
26#define COMMIT_PERIOD HZ
27
28/*
29 * The block size of the device holding pool data must be
30 * between 64KB and 1GB.
31 */
32#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
33#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
34
35/*
36 * Device id is restricted to 24 bits.
37 */
38#define MAX_DEV_ID ((1 << 24) - 1)
39
40/*
41 * How do we handle breaking sharing of data blocks?
42 * =================================================
43 *
44 * We use a standard copy-on-write btree to store the mappings for the
45 * devices (note I'm talking about copy-on-write of the metadata here, not
46 * the data). When you take an internal snapshot you clone the root node
47 * of the origin btree. After this there is no concept of an origin or a
48 * snapshot. They are just two device trees that happen to point to the
49 * same data blocks.
50 *
51 * When we get a write in we decide if it's to a shared data block using
52 * some timestamp magic. If it is, we have to break sharing.
53 *
54 * Let's say we write to a shared block in what was the origin. The
55 * steps are:
56 *
57 * i) plug io further to this physical block. (see bio_prison code).
58 *
59 * ii) quiesce any read io to that shared data block. Obviously
60 * including all devices that share this block. (see deferred_set code)
61 *
62 * iii) copy the data block to a newly allocate block. This step can be
63 * missed out if the io covers the block. (schedule_copy).
64 *
65 * iv) insert the new mapping into the origin's btree
66 * (process_prepared_mapping). This act of inserting breaks some
67 * sharing of btree nodes between the two devices. Breaking sharing only
68 * effects the btree of that specific device. Btrees for the other
69 * devices that share the block never change. The btree for the origin
70 * device as it was after the last commit is untouched, ie. we're using
71 * persistent data structures in the functional programming sense.
72 *
73 * v) unplug io to this physical block, including the io that triggered
74 * the breaking of sharing.
75 *
76 * Steps (ii) and (iii) occur in parallel.
77 *
78 * The metadata _doesn't_ need to be committed before the io continues. We
79 * get away with this because the io is always written to a _new_ block.
80 * If there's a crash, then:
81 *
82 * - The origin mapping will point to the old origin block (the shared
83 * one). This will contain the data as it was before the io that triggered
84 * the breaking of sharing came in.
85 *
86 * - The snap mapping still points to the old block. As it would after
87 * the commit.
88 *
89 * The downside of this scheme is the timestamp magic isn't perfect, and
90 * will continue to think that data block in the snapshot device is shared
91 * even after the write to the origin has broken sharing. I suspect data
92 * blocks will typically be shared by many different devices, so we're
93 * breaking sharing n + 1 times, rather than n, where n is the number of
94 * devices that reference this data block. At the moment I think the
95 * benefits far, far outweigh the disadvantages.
96 */
97
98/*----------------------------------------------------------------*/
99
100/*
101 * Sometimes we can't deal with a bio straight away. We put them in prison
102 * where they can't cause any mischief. Bios are put in a cell identified
103 * by a key, multiple bios can be in the same cell. When the cell is
104 * subsequently unlocked the bios become available.
105 */
106struct bio_prison;
107
108struct cell_key {
109 int virtual;
110 dm_thin_id dev;
111 dm_block_t block;
112};
113
114struct dm_bio_prison_cell {
115 struct hlist_node list;
116 struct bio_prison *prison;
117 struct cell_key key;
118 struct bio *holder;
119 struct bio_list bios;
120};
121
122struct bio_prison {
123 spinlock_t lock;
124 mempool_t *cell_pool;
125
126 unsigned nr_buckets;
127 unsigned hash_mask;
128 struct hlist_head *cells;
129};
130
131static uint32_t calc_nr_buckets(unsigned nr_cells)
132{
133 uint32_t n = 128;
134
135 nr_cells /= 4;
136 nr_cells = min(nr_cells, 8192u);
137
138 while (n < nr_cells)
139 n <<= 1;
140
141 return n;
142}
143
144static struct kmem_cache *_cell_cache;
145
146/*
147 * @nr_cells should be the number of cells you want in use _concurrently_.
148 * Don't confuse it with the number of distinct keys.
149 */
150static struct bio_prison *prison_create(unsigned nr_cells)
151{
152 unsigned i;
153 uint32_t nr_buckets = calc_nr_buckets(nr_cells);
154 size_t len = sizeof(struct bio_prison) +
155 (sizeof(struct hlist_head) * nr_buckets);
156 struct bio_prison *prison = kmalloc(len, GFP_KERNEL);
157
158 if (!prison)
159 return NULL;
160
161 spin_lock_init(&prison->lock);
162 prison->cell_pool = mempool_create_slab_pool(nr_cells, _cell_cache);
163 if (!prison->cell_pool) {
164 kfree(prison);
165 return NULL;
166 }
167
168 prison->nr_buckets = nr_buckets;
169 prison->hash_mask = nr_buckets - 1;
170 prison->cells = (struct hlist_head *) (prison + 1);
171 for (i = 0; i < nr_buckets; i++)
172 INIT_HLIST_HEAD(prison->cells + i);
173
174 return prison;
175}
176
177static void prison_destroy(struct bio_prison *prison)
178{
179 mempool_destroy(prison->cell_pool);
180 kfree(prison);
181}
182
183static uint32_t hash_key(struct bio_prison *prison, struct cell_key *key)
184{
185 const unsigned long BIG_PRIME = 4294967291UL;
186 uint64_t hash = key->block * BIG_PRIME;
187
188 return (uint32_t) (hash & prison->hash_mask);
189}
190
191static int keys_equal(struct cell_key *lhs, struct cell_key *rhs)
192{
193 return (lhs->virtual == rhs->virtual) &&
194 (lhs->dev == rhs->dev) &&
195 (lhs->block == rhs->block);
196}
197
198static struct dm_bio_prison_cell *__search_bucket(struct hlist_head *bucket,
199 struct cell_key *key)
200{
201 struct dm_bio_prison_cell *cell;
202 struct hlist_node *tmp;
203
204 hlist_for_each_entry(cell, tmp, bucket, list)
205 if (keys_equal(&cell->key, key))
206 return cell;
207
208 return NULL;
209}
210
211/*
212 * This may block if a new cell needs allocating. You must ensure that
213 * cells will be unlocked even if the calling thread is blocked.
214 *
215 * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
216 */
217static int bio_detain(struct bio_prison *prison, struct cell_key *key,
218 struct bio *inmate, struct dm_bio_prison_cell **ref)
219{
220 int r = 1;
221 unsigned long flags;
222 uint32_t hash = hash_key(prison, key);
223 struct dm_bio_prison_cell *cell, *cell2;
224
225 BUG_ON(hash > prison->nr_buckets);
226
227 spin_lock_irqsave(&prison->lock, flags);
228
229 cell = __search_bucket(prison->cells + hash, key);
230 if (cell) {
231 bio_list_add(&cell->bios, inmate);
232 goto out;
233 }
234
235 /*
236 * Allocate a new cell
237 */
238 spin_unlock_irqrestore(&prison->lock, flags);
239 cell2 = mempool_alloc(prison->cell_pool, GFP_NOIO);
240 spin_lock_irqsave(&prison->lock, flags);
241
242 /*
243 * We've been unlocked, so we have to double check that
244 * nobody else has inserted this cell in the meantime.
245 */
246 cell = __search_bucket(prison->cells + hash, key);
247 if (cell) {
248 mempool_free(cell2, prison->cell_pool);
249 bio_list_add(&cell->bios, inmate);
250 goto out;
251 }
252
253 /*
254 * Use new cell.
255 */
256 cell = cell2;
257
258 cell->prison = prison;
259 memcpy(&cell->key, key, sizeof(cell->key));
260 cell->holder = inmate;
261 bio_list_init(&cell->bios);
262 hlist_add_head(&cell->list, prison->cells + hash);
263
264 r = 0;
265
266out:
267 spin_unlock_irqrestore(&prison->lock, flags);
268
269 *ref = cell;
270
271 return r;
272}
273
274/*
275 * @inmates must have been initialised prior to this call
276 */
277static void __cell_release(struct dm_bio_prison_cell *cell, struct bio_list *inmates)
278{
279 struct bio_prison *prison = cell->prison;
280
281 hlist_del(&cell->list);
282
283 if (inmates) {
284 bio_list_add(inmates, cell->holder);
285 bio_list_merge(inmates, &cell->bios);
286 }
287
288 mempool_free(cell, prison->cell_pool);
289}
290
291static void cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios)
292{
293 unsigned long flags;
294 struct bio_prison *prison = cell->prison;
295
296 spin_lock_irqsave(&prison->lock, flags);
297 __cell_release(cell, bios);
298 spin_unlock_irqrestore(&prison->lock, flags);
299}
300
301/*
302 * There are a couple of places where we put a bio into a cell briefly
303 * before taking it out again. In these situations we know that no other
304 * bio may be in the cell. This function releases the cell, and also does
305 * a sanity check.
306 */
307static void __cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio)
308{
309 BUG_ON(cell->holder != bio);
310 BUG_ON(!bio_list_empty(&cell->bios));
311
312 __cell_release(cell, NULL);
313}
314
315static void cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio)
316{
317 unsigned long flags;
318 struct bio_prison *prison = cell->prison;
319
320 spin_lock_irqsave(&prison->lock, flags);
321 __cell_release_singleton(cell, bio);
322 spin_unlock_irqrestore(&prison->lock, flags);
323}
324
325/*
326 * Sometimes we don't want the holder, just the additional bios.
327 */
328static void __cell_release_no_holder(struct dm_bio_prison_cell *cell,
329 struct bio_list *inmates)
330{
331 struct bio_prison *prison = cell->prison;
332
333 hlist_del(&cell->list);
334 bio_list_merge(inmates, &cell->bios);
335
336 mempool_free(cell, prison->cell_pool);
337}
338
339static void cell_release_no_holder(struct dm_bio_prison_cell *cell,
340 struct bio_list *inmates)
341{
342 unsigned long flags;
343 struct bio_prison *prison = cell->prison;
344
345 spin_lock_irqsave(&prison->lock, flags);
346 __cell_release_no_holder(cell, inmates);
347 spin_unlock_irqrestore(&prison->lock, flags);
348}
349
350static void cell_error(struct dm_bio_prison_cell *cell)
351{
352 struct bio_prison *prison = cell->prison;
353 struct bio_list bios;
354 struct bio *bio;
355 unsigned long flags;
356
357 bio_list_init(&bios);
358
359 spin_lock_irqsave(&prison->lock, flags);
360 __cell_release(cell, &bios);
361 spin_unlock_irqrestore(&prison->lock, flags);
362
363 while ((bio = bio_list_pop(&bios)))
364 bio_io_error(bio);
365}
366
367/*----------------------------------------------------------------*/
368
369/*
370 * We use the deferred set to keep track of pending reads to shared blocks.
371 * We do this to ensure the new mapping caused by a write isn't performed
372 * until these prior reads have completed. Otherwise the insertion of the
373 * new mapping could free the old block that the read bios are mapped to.
374 */
375
376struct deferred_set;
377struct deferred_entry {
378 struct deferred_set *ds;
379 unsigned count;
380 struct list_head work_items;
381};
382
383struct deferred_set {
384 spinlock_t lock;
385 unsigned current_entry;
386 unsigned sweeper;
387 struct deferred_entry entries[DEFERRED_SET_SIZE];
388};
389
390static void ds_init(struct deferred_set *ds)
391{
392 int i;
393
394 spin_lock_init(&ds->lock);
395 ds->current_entry = 0;
396 ds->sweeper = 0;
397 for (i = 0; i < DEFERRED_SET_SIZE; i++) {
398 ds->entries[i].ds = ds;
399 ds->entries[i].count = 0;
400 INIT_LIST_HEAD(&ds->entries[i].work_items);
401 }
402}
403
404static struct deferred_entry *ds_inc(struct deferred_set *ds)
405{
406 unsigned long flags;
407 struct deferred_entry *entry;
408
409 spin_lock_irqsave(&ds->lock, flags);
410 entry = ds->entries + ds->current_entry;
411 entry->count++;
412 spin_unlock_irqrestore(&ds->lock, flags);
413
414 return entry;
415}
416
417static unsigned ds_next(unsigned index)
418{
419 return (index + 1) % DEFERRED_SET_SIZE;
420}
421
422static void __sweep(struct deferred_set *ds, struct list_head *head)
423{
424 while ((ds->sweeper != ds->current_entry) &&
425 !ds->entries[ds->sweeper].count) {
426 list_splice_init(&ds->entries[ds->sweeper].work_items, head);
427 ds->sweeper = ds_next(ds->sweeper);
428 }
429
430 if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count)
431 list_splice_init(&ds->entries[ds->sweeper].work_items, head);
432}
433
434static void ds_dec(struct deferred_entry *entry, struct list_head *head)
435{
436 unsigned long flags;
437
438 spin_lock_irqsave(&entry->ds->lock, flags);
439 BUG_ON(!entry->count);
440 --entry->count;
441 __sweep(entry->ds, head);
442 spin_unlock_irqrestore(&entry->ds->lock, flags);
443}
444
445/*
446 * Returns 1 if deferred or 0 if no pending items to delay job.
447 */
448static int ds_add_work(struct deferred_set *ds, struct list_head *work)
449{
450 int r = 1;
451 unsigned long flags;
452 unsigned next_entry;
453
454 spin_lock_irqsave(&ds->lock, flags);
455 if ((ds->sweeper == ds->current_entry) &&
456 !ds->entries[ds->current_entry].count)
457 r = 0;
458 else {
459 list_add(work, &ds->entries[ds->current_entry].work_items);
460 next_entry = ds_next(ds->current_entry);
461 if (!ds->entries[next_entry].count)
462 ds->current_entry = next_entry;
463 }
464 spin_unlock_irqrestore(&ds->lock, flags);
465
466 return r;
467}
468
469/*----------------------------------------------------------------*/
470
471/*
472 * Key building.
473 */
474static void build_data_key(struct dm_thin_device *td,
475 dm_block_t b, struct cell_key *key)
476{
477 key->virtual = 0;
478 key->dev = dm_thin_dev_id(td);
479 key->block = b;
480}
481
482static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
483 struct cell_key *key)
484{
485 key->virtual = 1;
486 key->dev = dm_thin_dev_id(td);
487 key->block = b;
488}
489
490/*----------------------------------------------------------------*/
491
492/*
493 * A pool device ties together a metadata device and a data device. It
494 * also provides the interface for creating and destroying internal
495 * devices.
496 */
497struct dm_thin_new_mapping;
498
499struct pool_features {
500 unsigned zero_new_blocks:1;
501 unsigned discard_enabled:1;
502 unsigned discard_passdown:1;
503};
504
505struct pool {
506 struct list_head list;
507 struct dm_target *ti; /* Only set if a pool target is bound */
508
509 struct mapped_device *pool_md;
510 struct block_device *md_dev;
511 struct dm_pool_metadata *pmd;
512
513 uint32_t sectors_per_block;
514 unsigned block_shift;
515 dm_block_t offset_mask;
516 dm_block_t low_water_blocks;
517
518 struct pool_features pf;
519 unsigned low_water_triggered:1; /* A dm event has been sent */
520 unsigned no_free_space:1; /* A -ENOSPC warning has been issued */
521
522 struct bio_prison *prison;
523 struct dm_kcopyd_client *copier;
524
525 struct workqueue_struct *wq;
526 struct work_struct worker;
527 struct delayed_work waker;
528
529 unsigned ref_count;
530 unsigned long last_commit_jiffies;
531
532 spinlock_t lock;
533 struct bio_list deferred_bios;
534 struct bio_list deferred_flush_bios;
535 struct list_head prepared_mappings;
536 struct list_head prepared_discards;
537
538 struct bio_list retry_on_resume_list;
539
540 struct deferred_set shared_read_ds;
541 struct deferred_set all_io_ds;
542
543 struct dm_thin_new_mapping *next_mapping;
544 mempool_t *mapping_pool;
545 mempool_t *endio_hook_pool;
546};
547
548/*
549 * Target context for a pool.
550 */
551struct pool_c {
552 struct dm_target *ti;
553 struct pool *pool;
554 struct dm_dev *data_dev;
555 struct dm_dev *metadata_dev;
556 struct dm_target_callbacks callbacks;
557
558 dm_block_t low_water_blocks;
559 struct pool_features pf;
560};
561
562/*
563 * Target context for a thin.
564 */
565struct thin_c {
566 struct dm_dev *pool_dev;
567 struct dm_dev *origin_dev;
568 dm_thin_id dev_id;
569
570 struct pool *pool;
571 struct dm_thin_device *td;
572};
573
574/*----------------------------------------------------------------*/
575
576/*
577 * A global list of pools that uses a struct mapped_device as a key.
578 */
579static struct dm_thin_pool_table {
580 struct mutex mutex;
581 struct list_head pools;
582} dm_thin_pool_table;
583
584static void pool_table_init(void)
585{
586 mutex_init(&dm_thin_pool_table.mutex);
587 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
588}
589
590static void __pool_table_insert(struct pool *pool)
591{
592 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
593 list_add(&pool->list, &dm_thin_pool_table.pools);
594}
595
596static void __pool_table_remove(struct pool *pool)
597{
598 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
599 list_del(&pool->list);
600}
601
602static struct pool *__pool_table_lookup(struct mapped_device *md)
603{
604 struct pool *pool = NULL, *tmp;
605
606 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
607
608 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
609 if (tmp->pool_md == md) {
610 pool = tmp;
611 break;
612 }
613 }
614
615 return pool;
616}
617
618static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
619{
620 struct pool *pool = NULL, *tmp;
621
622 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
623
624 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
625 if (tmp->md_dev == md_dev) {
626 pool = tmp;
627 break;
628 }
629 }
630
631 return pool;
632}
633
634/*----------------------------------------------------------------*/
635
636struct dm_thin_endio_hook {
637 struct thin_c *tc;
638 struct deferred_entry *shared_read_entry;
639 struct deferred_entry *all_io_entry;
640 struct dm_thin_new_mapping *overwrite_mapping;
641};
642
643static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
644{
645 struct bio *bio;
646 struct bio_list bios;
647
648 bio_list_init(&bios);
649 bio_list_merge(&bios, master);
650 bio_list_init(master);
651
652 while ((bio = bio_list_pop(&bios))) {
653 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
654
655 if (h->tc == tc)
656 bio_endio(bio, DM_ENDIO_REQUEUE);
657 else
658 bio_list_add(master, bio);
659 }
660}
661
662static void requeue_io(struct thin_c *tc)
663{
664 struct pool *pool = tc->pool;
665 unsigned long flags;
666
667 spin_lock_irqsave(&pool->lock, flags);
668 __requeue_bio_list(tc, &pool->deferred_bios);
669 __requeue_bio_list(tc, &pool->retry_on_resume_list);
670 spin_unlock_irqrestore(&pool->lock, flags);
671}
672
673/*
674 * This section of code contains the logic for processing a thin device's IO.
675 * Much of the code depends on pool object resources (lists, workqueues, etc)
676 * but most is exclusively called from the thin target rather than the thin-pool
677 * target.
678 */
679
680static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
681{
682 return bio->bi_sector >> tc->pool->block_shift;
683}
684
685static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
686{
687 struct pool *pool = tc->pool;
688
689 bio->bi_bdev = tc->pool_dev->bdev;
690 bio->bi_sector = (block << pool->block_shift) +
691 (bio->bi_sector & pool->offset_mask);
692}
693
694static void remap_to_origin(struct thin_c *tc, struct bio *bio)
695{
696 bio->bi_bdev = tc->origin_dev->bdev;
697}
698
699static void issue(struct thin_c *tc, struct bio *bio)
700{
701 struct pool *pool = tc->pool;
702 unsigned long flags;
703
704 /*
705 * Batch together any FUA/FLUSH bios we find and then issue
706 * a single commit for them in process_deferred_bios().
707 */
708 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
709 spin_lock_irqsave(&pool->lock, flags);
710 bio_list_add(&pool->deferred_flush_bios, bio);
711 spin_unlock_irqrestore(&pool->lock, flags);
712 } else
713 generic_make_request(bio);
714}
715
716static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
717{
718 remap_to_origin(tc, bio);
719 issue(tc, bio);
720}
721
722static void remap_and_issue(struct thin_c *tc, struct bio *bio,
723 dm_block_t block)
724{
725 remap(tc, bio, block);
726 issue(tc, bio);
727}
728
729/*
730 * wake_worker() is used when new work is queued and when pool_resume is
731 * ready to continue deferred IO processing.
732 */
733static void wake_worker(struct pool *pool)
734{
735 queue_work(pool->wq, &pool->worker);
736}
737
738/*----------------------------------------------------------------*/
739
740/*
741 * Bio endio functions.
742 */
743struct dm_thin_new_mapping {
744 struct list_head list;
745
746 unsigned quiesced:1;
747 unsigned prepared:1;
748 unsigned pass_discard:1;
749
750 struct thin_c *tc;
751 dm_block_t virt_block;
752 dm_block_t data_block;
753 struct dm_bio_prison_cell *cell, *cell2;
754 int err;
755
756 /*
757 * If the bio covers the whole area of a block then we can avoid
758 * zeroing or copying. Instead this bio is hooked. The bio will
759 * still be in the cell, so care has to be taken to avoid issuing
760 * the bio twice.
761 */
762 struct bio *bio;
763 bio_end_io_t *saved_bi_end_io;
764};
765
766static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
767{
768 struct pool *pool = m->tc->pool;
769
770 if (m->quiesced && m->prepared) {
771 list_add(&m->list, &pool->prepared_mappings);
772 wake_worker(pool);
773 }
774}
775
776static void copy_complete(int read_err, unsigned long write_err, void *context)
777{
778 unsigned long flags;
779 struct dm_thin_new_mapping *m = context;
780 struct pool *pool = m->tc->pool;
781
782 m->err = read_err || write_err ? -EIO : 0;
783
784 spin_lock_irqsave(&pool->lock, flags);
785 m->prepared = 1;
786 __maybe_add_mapping(m);
787 spin_unlock_irqrestore(&pool->lock, flags);
788}
789
790static void overwrite_endio(struct bio *bio, int err)
791{
792 unsigned long flags;
793 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
794 struct dm_thin_new_mapping *m = h->overwrite_mapping;
795 struct pool *pool = m->tc->pool;
796
797 m->err = err;
798
799 spin_lock_irqsave(&pool->lock, flags);
800 m->prepared = 1;
801 __maybe_add_mapping(m);
802 spin_unlock_irqrestore(&pool->lock, flags);
803}
804
805/*----------------------------------------------------------------*/
806
807/*
808 * Workqueue.
809 */
810
811/*
812 * Prepared mapping jobs.
813 */
814
815/*
816 * This sends the bios in the cell back to the deferred_bios list.
817 */
818static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell,
819 dm_block_t data_block)
820{
821 struct pool *pool = tc->pool;
822 unsigned long flags;
823
824 spin_lock_irqsave(&pool->lock, flags);
825 cell_release(cell, &pool->deferred_bios);
826 spin_unlock_irqrestore(&tc->pool->lock, flags);
827
828 wake_worker(pool);
829}
830
831/*
832 * Same as cell_defer above, except it omits one particular detainee,
833 * a write bio that covers the block and has already been processed.
834 */
835static void cell_defer_except(struct thin_c *tc, struct dm_bio_prison_cell *cell)
836{
837 struct bio_list bios;
838 struct pool *pool = tc->pool;
839 unsigned long flags;
840
841 bio_list_init(&bios);
842
843 spin_lock_irqsave(&pool->lock, flags);
844 cell_release_no_holder(cell, &pool->deferred_bios);
845 spin_unlock_irqrestore(&pool->lock, flags);
846
847 wake_worker(pool);
848}
849
850static void process_prepared_mapping(struct dm_thin_new_mapping *m)
851{
852 struct thin_c *tc = m->tc;
853 struct bio *bio;
854 int r;
855
856 bio = m->bio;
857 if (bio)
858 bio->bi_end_io = m->saved_bi_end_io;
859
860 if (m->err) {
861 cell_error(m->cell);
862 goto out;
863 }
864
865 /*
866 * Commit the prepared block into the mapping btree.
867 * Any I/O for this block arriving after this point will get
868 * remapped to it directly.
869 */
870 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
871 if (r) {
872 DMERR("dm_thin_insert_block() failed");
873 cell_error(m->cell);
874 goto out;
875 }
876
877 /*
878 * Release any bios held while the block was being provisioned.
879 * If we are processing a write bio that completely covers the block,
880 * we already processed it so can ignore it now when processing
881 * the bios in the cell.
882 */
883 if (bio) {
884 cell_defer_except(tc, m->cell);
885 bio_endio(bio, 0);
886 } else
887 cell_defer(tc, m->cell, m->data_block);
888
889out:
890 list_del(&m->list);
891 mempool_free(m, tc->pool->mapping_pool);
892}
893
894static void process_prepared_discard(struct dm_thin_new_mapping *m)
895{
896 int r;
897 struct thin_c *tc = m->tc;
898
899 r = dm_thin_remove_block(tc->td, m->virt_block);
900 if (r)
901 DMERR("dm_thin_remove_block() failed");
902
903 /*
904 * Pass the discard down to the underlying device?
905 */
906 if (m->pass_discard)
907 remap_and_issue(tc, m->bio, m->data_block);
908 else
909 bio_endio(m->bio, 0);
910
911 cell_defer_except(tc, m->cell);
912 cell_defer_except(tc, m->cell2);
913 mempool_free(m, tc->pool->mapping_pool);
914}
915
916static void process_prepared(struct pool *pool, struct list_head *head,
917 void (*fn)(struct dm_thin_new_mapping *))
918{
919 unsigned long flags;
920 struct list_head maps;
921 struct dm_thin_new_mapping *m, *tmp;
922
923 INIT_LIST_HEAD(&maps);
924 spin_lock_irqsave(&pool->lock, flags);
925 list_splice_init(head, &maps);
926 spin_unlock_irqrestore(&pool->lock, flags);
927
928 list_for_each_entry_safe(m, tmp, &maps, list)
929 fn(m);
930}
931
932/*
933 * Deferred bio jobs.
934 */
935static int io_overlaps_block(struct pool *pool, struct bio *bio)
936{
937 return !(bio->bi_sector & pool->offset_mask) &&
938 (bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT));
939
940}
941
942static int io_overwrites_block(struct pool *pool, struct bio *bio)
943{
944 return (bio_data_dir(bio) == WRITE) &&
945 io_overlaps_block(pool, bio);
946}
947
948static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
949 bio_end_io_t *fn)
950{
951 *save = bio->bi_end_io;
952 bio->bi_end_io = fn;
953}
954
955static int ensure_next_mapping(struct pool *pool)
956{
957 if (pool->next_mapping)
958 return 0;
959
960 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
961
962 return pool->next_mapping ? 0 : -ENOMEM;
963}
964
965static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
966{
967 struct dm_thin_new_mapping *r = pool->next_mapping;
968
969 BUG_ON(!pool->next_mapping);
970
971 pool->next_mapping = NULL;
972
973 return r;
974}
975
976static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
977 struct dm_dev *origin, dm_block_t data_origin,
978 dm_block_t data_dest,
979 struct dm_bio_prison_cell *cell, struct bio *bio)
980{
981 int r;
982 struct pool *pool = tc->pool;
983 struct dm_thin_new_mapping *m = get_next_mapping(pool);
984
985 INIT_LIST_HEAD(&m->list);
986 m->quiesced = 0;
987 m->prepared = 0;
988 m->tc = tc;
989 m->virt_block = virt_block;
990 m->data_block = data_dest;
991 m->cell = cell;
992 m->err = 0;
993 m->bio = NULL;
994
995 if (!ds_add_work(&pool->shared_read_ds, &m->list))
996 m->quiesced = 1;
997
998 /*
999 * IO to pool_dev remaps to the pool target's data_dev.
1000 *
1001 * If the whole block of data is being overwritten, we can issue the
1002 * bio immediately. Otherwise we use kcopyd to clone the data first.
1003 */
1004 if (io_overwrites_block(pool, bio)) {
1005 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
1006
1007 h->overwrite_mapping = m;
1008 m->bio = bio;
1009 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
1010 remap_and_issue(tc, bio, data_dest);
1011 } else {
1012 struct dm_io_region from, to;
1013
1014 from.bdev = origin->bdev;
1015 from.sector = data_origin * pool->sectors_per_block;
1016 from.count = pool->sectors_per_block;
1017
1018 to.bdev = tc->pool_dev->bdev;
1019 to.sector = data_dest * pool->sectors_per_block;
1020 to.count = pool->sectors_per_block;
1021
1022 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
1023 0, copy_complete, m);
1024 if (r < 0) {
1025 mempool_free(m, pool->mapping_pool);
1026 DMERR("dm_kcopyd_copy() failed");
1027 cell_error(cell);
1028 }
1029 }
1030}
1031
1032static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
1033 dm_block_t data_origin, dm_block_t data_dest,
1034 struct dm_bio_prison_cell *cell, struct bio *bio)
1035{
1036 schedule_copy(tc, virt_block, tc->pool_dev,
1037 data_origin, data_dest, cell, bio);
1038}
1039
1040static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1041 dm_block_t data_dest,
1042 struct dm_bio_prison_cell *cell, struct bio *bio)
1043{
1044 schedule_copy(tc, virt_block, tc->origin_dev,
1045 virt_block, data_dest, cell, bio);
1046}
1047
1048static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
1049 dm_block_t data_block, struct dm_bio_prison_cell *cell,
1050 struct bio *bio)
1051{
1052 struct pool *pool = tc->pool;
1053 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1054
1055 INIT_LIST_HEAD(&m->list);
1056 m->quiesced = 1;
1057 m->prepared = 0;
1058 m->tc = tc;
1059 m->virt_block = virt_block;
1060 m->data_block = data_block;
1061 m->cell = cell;
1062 m->err = 0;
1063 m->bio = NULL;
1064
1065 /*
1066 * If the whole block of data is being overwritten or we are not
1067 * zeroing pre-existing data, we can issue the bio immediately.
1068 * Otherwise we use kcopyd to zero the data first.
1069 */
1070 if (!pool->pf.zero_new_blocks)
1071 process_prepared_mapping(m);
1072
1073 else if (io_overwrites_block(pool, bio)) {
1074 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
1075
1076 h->overwrite_mapping = m;
1077 m->bio = bio;
1078 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
1079 remap_and_issue(tc, bio, data_block);
1080 } else {
1081 int r;
1082 struct dm_io_region to;
1083
1084 to.bdev = tc->pool_dev->bdev;
1085 to.sector = data_block * pool->sectors_per_block;
1086 to.count = pool->sectors_per_block;
1087
1088 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
1089 if (r < 0) {
1090 mempool_free(m, pool->mapping_pool);
1091 DMERR("dm_kcopyd_zero() failed");
1092 cell_error(cell);
1093 }
1094 }
1095}
1096
1097static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1098{
1099 int r;
1100 dm_block_t free_blocks;
1101 unsigned long flags;
1102 struct pool *pool = tc->pool;
1103
1104 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1105 if (r)
1106 return r;
1107
1108 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1109 DMWARN("%s: reached low water mark, sending event.",
1110 dm_device_name(pool->pool_md));
1111 spin_lock_irqsave(&pool->lock, flags);
1112 pool->low_water_triggered = 1;
1113 spin_unlock_irqrestore(&pool->lock, flags);
1114 dm_table_event(pool->ti->table);
1115 }
1116
1117 if (!free_blocks) {
1118 if (pool->no_free_space)
1119 return -ENOSPC;
1120 else {
1121 /*
1122 * Try to commit to see if that will free up some
1123 * more space.
1124 */
1125 r = dm_pool_commit_metadata(pool->pmd);
1126 if (r) {
1127 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1128 __func__, r);
1129 return r;
1130 }
1131
1132 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1133 if (r)
1134 return r;
1135
1136 /*
1137 * If we still have no space we set a flag to avoid
1138 * doing all this checking and return -ENOSPC.
1139 */
1140 if (!free_blocks) {
1141 DMWARN("%s: no free space available.",
1142 dm_device_name(pool->pool_md));
1143 spin_lock_irqsave(&pool->lock, flags);
1144 pool->no_free_space = 1;
1145 spin_unlock_irqrestore(&pool->lock, flags);
1146 return -ENOSPC;
1147 }
1148 }
1149 }
1150
1151 r = dm_pool_alloc_data_block(pool->pmd, result);
1152 if (r)
1153 return r;
1154
1155 return 0;
1156}
1157
1158/*
1159 * If we have run out of space, queue bios until the device is
1160 * resumed, presumably after having been reloaded with more space.
1161 */
1162static void retry_on_resume(struct bio *bio)
1163{
1164 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
1165 struct thin_c *tc = h->tc;
1166 struct pool *pool = tc->pool;
1167 unsigned long flags;
1168
1169 spin_lock_irqsave(&pool->lock, flags);
1170 bio_list_add(&pool->retry_on_resume_list, bio);
1171 spin_unlock_irqrestore(&pool->lock, flags);
1172}
1173
1174static void no_space(struct dm_bio_prison_cell *cell)
1175{
1176 struct bio *bio;
1177 struct bio_list bios;
1178
1179 bio_list_init(&bios);
1180 cell_release(cell, &bios);
1181
1182 while ((bio = bio_list_pop(&bios)))
1183 retry_on_resume(bio);
1184}
1185
1186static void process_discard(struct thin_c *tc, struct bio *bio)
1187{
1188 int r;
1189 unsigned long flags;
1190 struct pool *pool = tc->pool;
1191 struct dm_bio_prison_cell *cell, *cell2;
1192 struct cell_key key, key2;
1193 dm_block_t block = get_bio_block(tc, bio);
1194 struct dm_thin_lookup_result lookup_result;
1195 struct dm_thin_new_mapping *m;
1196
1197 build_virtual_key(tc->td, block, &key);
1198 if (bio_detain(tc->pool->prison, &key, bio, &cell))
1199 return;
1200
1201 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1202 switch (r) {
1203 case 0:
1204 /*
1205 * Check nobody is fiddling with this pool block. This can
1206 * happen if someone's in the process of breaking sharing
1207 * on this block.
1208 */
1209 build_data_key(tc->td, lookup_result.block, &key2);
1210 if (bio_detain(tc->pool->prison, &key2, bio, &cell2)) {
1211 cell_release_singleton(cell, bio);
1212 break;
1213 }
1214
1215 if (io_overlaps_block(pool, bio)) {
1216 /*
1217 * IO may still be going to the destination block. We must
1218 * quiesce before we can do the removal.
1219 */
1220 m = get_next_mapping(pool);
1221 m->tc = tc;
1222 m->pass_discard = (!lookup_result.shared) & pool->pf.discard_passdown;
1223 m->virt_block = block;
1224 m->data_block = lookup_result.block;
1225 m->cell = cell;
1226 m->cell2 = cell2;
1227 m->err = 0;
1228 m->bio = bio;
1229
1230 if (!ds_add_work(&pool->all_io_ds, &m->list)) {
1231 spin_lock_irqsave(&pool->lock, flags);
1232 list_add(&m->list, &pool->prepared_discards);
1233 spin_unlock_irqrestore(&pool->lock, flags);
1234 wake_worker(pool);
1235 }
1236 } else {
1237 /*
1238 * This path is hit if people are ignoring
1239 * limits->discard_granularity. It ignores any
1240 * part of the discard that is in a subsequent
1241 * block.
1242 */
1243 sector_t offset = bio->bi_sector - (block << pool->block_shift);
1244 unsigned remaining = (pool->sectors_per_block - offset) << 9;
1245 bio->bi_size = min(bio->bi_size, remaining);
1246
1247 cell_release_singleton(cell, bio);
1248 cell_release_singleton(cell2, bio);
1249 if ((!lookup_result.shared) && pool->pf.discard_passdown)
1250 remap_and_issue(tc, bio, lookup_result.block);
1251 else
1252 bio_endio(bio, 0);
1253 }
1254 break;
1255
1256 case -ENODATA:
1257 /*
1258 * It isn't provisioned, just forget it.
1259 */
1260 cell_release_singleton(cell, bio);
1261 bio_endio(bio, 0);
1262 break;
1263
1264 default:
1265 DMERR("discard: find block unexpectedly returned %d", r);
1266 cell_release_singleton(cell, bio);
1267 bio_io_error(bio);
1268 break;
1269 }
1270}
1271
1272static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1273 struct cell_key *key,
1274 struct dm_thin_lookup_result *lookup_result,
1275 struct dm_bio_prison_cell *cell)
1276{
1277 int r;
1278 dm_block_t data_block;
1279
1280 r = alloc_data_block(tc, &data_block);
1281 switch (r) {
1282 case 0:
1283 schedule_internal_copy(tc, block, lookup_result->block,
1284 data_block, cell, bio);
1285 break;
1286
1287 case -ENOSPC:
1288 no_space(cell);
1289 break;
1290
1291 default:
1292 DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
1293 cell_error(cell);
1294 break;
1295 }
1296}
1297
1298static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1299 dm_block_t block,
1300 struct dm_thin_lookup_result *lookup_result)
1301{
1302 struct dm_bio_prison_cell *cell;
1303 struct pool *pool = tc->pool;
1304 struct cell_key key;
1305
1306 /*
1307 * If cell is already occupied, then sharing is already in the process
1308 * of being broken so we have nothing further to do here.
1309 */
1310 build_data_key(tc->td, lookup_result->block, &key);
1311 if (bio_detain(pool->prison, &key, bio, &cell))
1312 return;
1313
1314 if (bio_data_dir(bio) == WRITE)
1315 break_sharing(tc, bio, block, &key, lookup_result, cell);
1316 else {
1317 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
1318
1319 h->shared_read_entry = ds_inc(&pool->shared_read_ds);
1320
1321 cell_release_singleton(cell, bio);
1322 remap_and_issue(tc, bio, lookup_result->block);
1323 }
1324}
1325
1326static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1327 struct dm_bio_prison_cell *cell)
1328{
1329 int r;
1330 dm_block_t data_block;
1331
1332 /*
1333 * Remap empty bios (flushes) immediately, without provisioning.
1334 */
1335 if (!bio->bi_size) {
1336 cell_release_singleton(cell, bio);
1337 remap_and_issue(tc, bio, 0);
1338 return;
1339 }
1340
1341 /*
1342 * Fill read bios with zeroes and complete them immediately.
1343 */
1344 if (bio_data_dir(bio) == READ) {
1345 zero_fill_bio(bio);
1346 cell_release_singleton(cell, bio);
1347 bio_endio(bio, 0);
1348 return;
1349 }
1350
1351 r = alloc_data_block(tc, &data_block);
1352 switch (r) {
1353 case 0:
1354 if (tc->origin_dev)
1355 schedule_external_copy(tc, block, data_block, cell, bio);
1356 else
1357 schedule_zero(tc, block, data_block, cell, bio);
1358 break;
1359
1360 case -ENOSPC:
1361 no_space(cell);
1362 break;
1363
1364 default:
1365 DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
1366 cell_error(cell);
1367 break;
1368 }
1369}
1370
1371static void process_bio(struct thin_c *tc, struct bio *bio)
1372{
1373 int r;
1374 dm_block_t block = get_bio_block(tc, bio);
1375 struct dm_bio_prison_cell *cell;
1376 struct cell_key key;
1377 struct dm_thin_lookup_result lookup_result;
1378
1379 /*
1380 * If cell is already occupied, then the block is already
1381 * being provisioned so we have nothing further to do here.
1382 */
1383 build_virtual_key(tc->td, block, &key);
1384 if (bio_detain(tc->pool->prison, &key, bio, &cell))
1385 return;
1386
1387 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1388 switch (r) {
1389 case 0:
1390 /*
1391 * We can release this cell now. This thread is the only
1392 * one that puts bios into a cell, and we know there were
1393 * no preceding bios.
1394 */
1395 /*
1396 * TODO: this will probably have to change when discard goes
1397 * back in.
1398 */
1399 cell_release_singleton(cell, bio);
1400
1401 if (lookup_result.shared)
1402 process_shared_bio(tc, bio, block, &lookup_result);
1403 else
1404 remap_and_issue(tc, bio, lookup_result.block);
1405 break;
1406
1407 case -ENODATA:
1408 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1409 cell_release_singleton(cell, bio);
1410 remap_to_origin_and_issue(tc, bio);
1411 } else
1412 provision_block(tc, bio, block, cell);
1413 break;
1414
1415 default:
1416 DMERR("dm_thin_find_block() failed, error = %d", r);
1417 cell_release_singleton(cell, bio);
1418 bio_io_error(bio);
1419 break;
1420 }
1421}
1422
1423static int need_commit_due_to_time(struct pool *pool)
1424{
1425 return jiffies < pool->last_commit_jiffies ||
1426 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1427}
1428
1429static void process_deferred_bios(struct pool *pool)
1430{
1431 unsigned long flags;
1432 struct bio *bio;
1433 struct bio_list bios;
1434 int r;
1435
1436 bio_list_init(&bios);
1437
1438 spin_lock_irqsave(&pool->lock, flags);
1439 bio_list_merge(&bios, &pool->deferred_bios);
1440 bio_list_init(&pool->deferred_bios);
1441 spin_unlock_irqrestore(&pool->lock, flags);
1442
1443 while ((bio = bio_list_pop(&bios))) {
1444 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
1445 struct thin_c *tc = h->tc;
1446
1447 /*
1448 * If we've got no free new_mapping structs, and processing
1449 * this bio might require one, we pause until there are some
1450 * prepared mappings to process.
1451 */
1452 if (ensure_next_mapping(pool)) {
1453 spin_lock_irqsave(&pool->lock, flags);
1454 bio_list_merge(&pool->deferred_bios, &bios);
1455 spin_unlock_irqrestore(&pool->lock, flags);
1456
1457 break;
1458 }
1459
1460 if (bio->bi_rw & REQ_DISCARD)
1461 process_discard(tc, bio);
1462 else
1463 process_bio(tc, bio);
1464 }
1465
1466 /*
1467 * If there are any deferred flush bios, we must commit
1468 * the metadata before issuing them.
1469 */
1470 bio_list_init(&bios);
1471 spin_lock_irqsave(&pool->lock, flags);
1472 bio_list_merge(&bios, &pool->deferred_flush_bios);
1473 bio_list_init(&pool->deferred_flush_bios);
1474 spin_unlock_irqrestore(&pool->lock, flags);
1475
1476 if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))
1477 return;
1478
1479 r = dm_pool_commit_metadata(pool->pmd);
1480 if (r) {
1481 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1482 __func__, r);
1483 while ((bio = bio_list_pop(&bios)))
1484 bio_io_error(bio);
1485 return;
1486 }
1487 pool->last_commit_jiffies = jiffies;
1488
1489 while ((bio = bio_list_pop(&bios)))
1490 generic_make_request(bio);
1491}
1492
1493static void do_worker(struct work_struct *ws)
1494{
1495 struct pool *pool = container_of(ws, struct pool, worker);
1496
1497 process_prepared(pool, &pool->prepared_mappings, process_prepared_mapping);
1498 process_prepared(pool, &pool->prepared_discards, process_prepared_discard);
1499 process_deferred_bios(pool);
1500}
1501
1502/*
1503 * We want to commit periodically so that not too much
1504 * unwritten data builds up.
1505 */
1506static void do_waker(struct work_struct *ws)
1507{
1508 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1509 wake_worker(pool);
1510 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1511}
1512
1513/*----------------------------------------------------------------*/
1514
1515/*
1516 * Mapping functions.
1517 */
1518
1519/*
1520 * Called only while mapping a thin bio to hand it over to the workqueue.
1521 */
1522static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1523{
1524 unsigned long flags;
1525 struct pool *pool = tc->pool;
1526
1527 spin_lock_irqsave(&pool->lock, flags);
1528 bio_list_add(&pool->deferred_bios, bio);
1529 spin_unlock_irqrestore(&pool->lock, flags);
1530
1531 wake_worker(pool);
1532}
1533
1534static struct dm_thin_endio_hook *thin_hook_bio(struct thin_c *tc, struct bio *bio)
1535{
1536 struct pool *pool = tc->pool;
1537 struct dm_thin_endio_hook *h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO);
1538
1539 h->tc = tc;
1540 h->shared_read_entry = NULL;
1541 h->all_io_entry = bio->bi_rw & REQ_DISCARD ? NULL : ds_inc(&pool->all_io_ds);
1542 h->overwrite_mapping = NULL;
1543
1544 return h;
1545}
1546
1547/*
1548 * Non-blocking function called from the thin target's map function.
1549 */
1550static int thin_bio_map(struct dm_target *ti, struct bio *bio,
1551 union map_info *map_context)
1552{
1553 int r;
1554 struct thin_c *tc = ti->private;
1555 dm_block_t block = get_bio_block(tc, bio);
1556 struct dm_thin_device *td = tc->td;
1557 struct dm_thin_lookup_result result;
1558
1559 map_context->ptr = thin_hook_bio(tc, bio);
1560 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
1561 thin_defer_bio(tc, bio);
1562 return DM_MAPIO_SUBMITTED;
1563 }
1564
1565 r = dm_thin_find_block(td, block, 0, &result);
1566
1567 /*
1568 * Note that we defer readahead too.
1569 */
1570 switch (r) {
1571 case 0:
1572 if (unlikely(result.shared)) {
1573 /*
1574 * We have a race condition here between the
1575 * result.shared value returned by the lookup and
1576 * snapshot creation, which may cause new
1577 * sharing.
1578 *
1579 * To avoid this always quiesce the origin before
1580 * taking the snap. You want to do this anyway to
1581 * ensure a consistent application view
1582 * (i.e. lockfs).
1583 *
1584 * More distant ancestors are irrelevant. The
1585 * shared flag will be set in their case.
1586 */
1587 thin_defer_bio(tc, bio);
1588 r = DM_MAPIO_SUBMITTED;
1589 } else {
1590 remap(tc, bio, result.block);
1591 r = DM_MAPIO_REMAPPED;
1592 }
1593 break;
1594
1595 case -ENODATA:
1596 /*
1597 * In future, the failed dm_thin_find_block above could
1598 * provide the hint to load the metadata into cache.
1599 */
1600 case -EWOULDBLOCK:
1601 thin_defer_bio(tc, bio);
1602 r = DM_MAPIO_SUBMITTED;
1603 break;
1604 }
1605
1606 return r;
1607}
1608
1609static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1610{
1611 int r;
1612 unsigned long flags;
1613 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1614
1615 spin_lock_irqsave(&pt->pool->lock, flags);
1616 r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1617 spin_unlock_irqrestore(&pt->pool->lock, flags);
1618
1619 if (!r) {
1620 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1621 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1622 }
1623
1624 return r;
1625}
1626
1627static void __requeue_bios(struct pool *pool)
1628{
1629 bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1630 bio_list_init(&pool->retry_on_resume_list);
1631}
1632
1633/*----------------------------------------------------------------
1634 * Binding of control targets to a pool object
1635 *--------------------------------------------------------------*/
1636static int bind_control_target(struct pool *pool, struct dm_target *ti)
1637{
1638 struct pool_c *pt = ti->private;
1639
1640 pool->ti = ti;
1641 pool->low_water_blocks = pt->low_water_blocks;
1642 pool->pf = pt->pf;
1643
1644 /*
1645 * If discard_passdown was enabled verify that the data device
1646 * supports discards. Disable discard_passdown if not; otherwise
1647 * -EOPNOTSUPP will be returned.
1648 */
1649 if (pt->pf.discard_passdown) {
1650 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1651 if (!q || !blk_queue_discard(q)) {
1652 char buf[BDEVNAME_SIZE];
1653 DMWARN("Discard unsupported by data device (%s): Disabling discard passdown.",
1654 bdevname(pt->data_dev->bdev, buf));
1655 pool->pf.discard_passdown = 0;
1656 }
1657 }
1658
1659 return 0;
1660}
1661
1662static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1663{
1664 if (pool->ti == ti)
1665 pool->ti = NULL;
1666}
1667
1668/*----------------------------------------------------------------
1669 * Pool creation
1670 *--------------------------------------------------------------*/
1671/* Initialize pool features. */
1672static void pool_features_init(struct pool_features *pf)
1673{
1674 pf->zero_new_blocks = 1;
1675 pf->discard_enabled = 1;
1676 pf->discard_passdown = 1;
1677}
1678
1679static void __pool_destroy(struct pool *pool)
1680{
1681 __pool_table_remove(pool);
1682
1683 if (dm_pool_metadata_close(pool->pmd) < 0)
1684 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1685
1686 prison_destroy(pool->prison);
1687 dm_kcopyd_client_destroy(pool->copier);
1688
1689 if (pool->wq)
1690 destroy_workqueue(pool->wq);
1691
1692 if (pool->next_mapping)
1693 mempool_free(pool->next_mapping, pool->mapping_pool);
1694 mempool_destroy(pool->mapping_pool);
1695 mempool_destroy(pool->endio_hook_pool);
1696 kfree(pool);
1697}
1698
1699static struct kmem_cache *_new_mapping_cache;
1700static struct kmem_cache *_endio_hook_cache;
1701
1702static struct pool *pool_create(struct mapped_device *pool_md,
1703 struct block_device *metadata_dev,
1704 unsigned long block_size, char **error)
1705{
1706 int r;
1707 void *err_p;
1708 struct pool *pool;
1709 struct dm_pool_metadata *pmd;
1710
1711 pmd = dm_pool_metadata_open(metadata_dev, block_size);
1712 if (IS_ERR(pmd)) {
1713 *error = "Error creating metadata object";
1714 return (struct pool *)pmd;
1715 }
1716
1717 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1718 if (!pool) {
1719 *error = "Error allocating memory for pool";
1720 err_p = ERR_PTR(-ENOMEM);
1721 goto bad_pool;
1722 }
1723
1724 pool->pmd = pmd;
1725 pool->sectors_per_block = block_size;
1726 pool->block_shift = ffs(block_size) - 1;
1727 pool->offset_mask = block_size - 1;
1728 pool->low_water_blocks = 0;
1729 pool_features_init(&pool->pf);
1730 pool->prison = prison_create(PRISON_CELLS);
1731 if (!pool->prison) {
1732 *error = "Error creating pool's bio prison";
1733 err_p = ERR_PTR(-ENOMEM);
1734 goto bad_prison;
1735 }
1736
1737 pool->copier = dm_kcopyd_client_create();
1738 if (IS_ERR(pool->copier)) {
1739 r = PTR_ERR(pool->copier);
1740 *error = "Error creating pool's kcopyd client";
1741 err_p = ERR_PTR(r);
1742 goto bad_kcopyd_client;
1743 }
1744
1745 /*
1746 * Create singlethreaded workqueue that will service all devices
1747 * that use this metadata.
1748 */
1749 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1750 if (!pool->wq) {
1751 *error = "Error creating pool's workqueue";
1752 err_p = ERR_PTR(-ENOMEM);
1753 goto bad_wq;
1754 }
1755
1756 INIT_WORK(&pool->worker, do_worker);
1757 INIT_DELAYED_WORK(&pool->waker, do_waker);
1758 spin_lock_init(&pool->lock);
1759 bio_list_init(&pool->deferred_bios);
1760 bio_list_init(&pool->deferred_flush_bios);
1761 INIT_LIST_HEAD(&pool->prepared_mappings);
1762 INIT_LIST_HEAD(&pool->prepared_discards);
1763 pool->low_water_triggered = 0;
1764 pool->no_free_space = 0;
1765 bio_list_init(&pool->retry_on_resume_list);
1766 ds_init(&pool->shared_read_ds);
1767 ds_init(&pool->all_io_ds);
1768
1769 pool->next_mapping = NULL;
1770 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
1771 _new_mapping_cache);
1772 if (!pool->mapping_pool) {
1773 *error = "Error creating pool's mapping mempool";
1774 err_p = ERR_PTR(-ENOMEM);
1775 goto bad_mapping_pool;
1776 }
1777
1778 pool->endio_hook_pool = mempool_create_slab_pool(ENDIO_HOOK_POOL_SIZE,
1779 _endio_hook_cache);
1780 if (!pool->endio_hook_pool) {
1781 *error = "Error creating pool's endio_hook mempool";
1782 err_p = ERR_PTR(-ENOMEM);
1783 goto bad_endio_hook_pool;
1784 }
1785 pool->ref_count = 1;
1786 pool->last_commit_jiffies = jiffies;
1787 pool->pool_md = pool_md;
1788 pool->md_dev = metadata_dev;
1789 __pool_table_insert(pool);
1790
1791 return pool;
1792
1793bad_endio_hook_pool:
1794 mempool_destroy(pool->mapping_pool);
1795bad_mapping_pool:
1796 destroy_workqueue(pool->wq);
1797bad_wq:
1798 dm_kcopyd_client_destroy(pool->copier);
1799bad_kcopyd_client:
1800 prison_destroy(pool->prison);
1801bad_prison:
1802 kfree(pool);
1803bad_pool:
1804 if (dm_pool_metadata_close(pmd))
1805 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1806
1807 return err_p;
1808}
1809
1810static void __pool_inc(struct pool *pool)
1811{
1812 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1813 pool->ref_count++;
1814}
1815
1816static void __pool_dec(struct pool *pool)
1817{
1818 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1819 BUG_ON(!pool->ref_count);
1820 if (!--pool->ref_count)
1821 __pool_destroy(pool);
1822}
1823
1824static struct pool *__pool_find(struct mapped_device *pool_md,
1825 struct block_device *metadata_dev,
1826 unsigned long block_size, char **error,
1827 int *created)
1828{
1829 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1830
1831 if (pool) {
1832 if (pool->pool_md != pool_md)
1833 return ERR_PTR(-EBUSY);
1834 __pool_inc(pool);
1835
1836 } else {
1837 pool = __pool_table_lookup(pool_md);
1838 if (pool) {
1839 if (pool->md_dev != metadata_dev)
1840 return ERR_PTR(-EINVAL);
1841 __pool_inc(pool);
1842
1843 } else {
1844 pool = pool_create(pool_md, metadata_dev, block_size, error);
1845 *created = 1;
1846 }
1847 }
1848
1849 return pool;
1850}
1851
1852/*----------------------------------------------------------------
1853 * Pool target methods
1854 *--------------------------------------------------------------*/
1855static void pool_dtr(struct dm_target *ti)
1856{
1857 struct pool_c *pt = ti->private;
1858
1859 mutex_lock(&dm_thin_pool_table.mutex);
1860
1861 unbind_control_target(pt->pool, ti);
1862 __pool_dec(pt->pool);
1863 dm_put_device(ti, pt->metadata_dev);
1864 dm_put_device(ti, pt->data_dev);
1865 kfree(pt);
1866
1867 mutex_unlock(&dm_thin_pool_table.mutex);
1868}
1869
1870static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
1871 struct dm_target *ti)
1872{
1873 int r;
1874 unsigned argc;
1875 const char *arg_name;
1876
1877 static struct dm_arg _args[] = {
1878 {0, 3, "Invalid number of pool feature arguments"},
1879 };
1880
1881 /*
1882 * No feature arguments supplied.
1883 */
1884 if (!as->argc)
1885 return 0;
1886
1887 r = dm_read_arg_group(_args, as, &argc, &ti->error);
1888 if (r)
1889 return -EINVAL;
1890
1891 while (argc && !r) {
1892 arg_name = dm_shift_arg(as);
1893 argc--;
1894
1895 if (!strcasecmp(arg_name, "skip_block_zeroing")) {
1896 pf->zero_new_blocks = 0;
1897 continue;
1898 } else if (!strcasecmp(arg_name, "ignore_discard")) {
1899 pf->discard_enabled = 0;
1900 continue;
1901 } else if (!strcasecmp(arg_name, "no_discard_passdown")) {
1902 pf->discard_passdown = 0;
1903 continue;
1904 }
1905
1906 ti->error = "Unrecognised pool feature requested";
1907 r = -EINVAL;
1908 }
1909
1910 return r;
1911}
1912
1913/*
1914 * thin-pool <metadata dev> <data dev>
1915 * <data block size (sectors)>
1916 * <low water mark (blocks)>
1917 * [<#feature args> [<arg>]*]
1918 *
1919 * Optional feature arguments are:
1920 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1921 * ignore_discard: disable discard
1922 * no_discard_passdown: don't pass discards down to the data device
1923 */
1924static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
1925{
1926 int r, pool_created = 0;
1927 struct pool_c *pt;
1928 struct pool *pool;
1929 struct pool_features pf;
1930 struct dm_arg_set as;
1931 struct dm_dev *data_dev;
1932 unsigned long block_size;
1933 dm_block_t low_water_blocks;
1934 struct dm_dev *metadata_dev;
1935 sector_t metadata_dev_size;
1936 char b[BDEVNAME_SIZE];
1937
1938 /*
1939 * FIXME Remove validation from scope of lock.
1940 */
1941 mutex_lock(&dm_thin_pool_table.mutex);
1942
1943 if (argc < 4) {
1944 ti->error = "Invalid argument count";
1945 r = -EINVAL;
1946 goto out_unlock;
1947 }
1948 as.argc = argc;
1949 as.argv = argv;
1950
1951 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev);
1952 if (r) {
1953 ti->error = "Error opening metadata block device";
1954 goto out_unlock;
1955 }
1956
1957 metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT;
1958 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
1959 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1960 bdevname(metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
1961
1962 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
1963 if (r) {
1964 ti->error = "Error getting data device";
1965 goto out_metadata;
1966 }
1967
1968 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
1969 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
1970 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
1971 !is_power_of_2(block_size)) {
1972 ti->error = "Invalid block size";
1973 r = -EINVAL;
1974 goto out;
1975 }
1976
1977 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
1978 ti->error = "Invalid low water mark";
1979 r = -EINVAL;
1980 goto out;
1981 }
1982
1983 /*
1984 * Set default pool features.
1985 */
1986 pool_features_init(&pf);
1987
1988 dm_consume_args(&as, 4);
1989 r = parse_pool_features(&as, &pf, ti);
1990 if (r)
1991 goto out;
1992
1993 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
1994 if (!pt) {
1995 r = -ENOMEM;
1996 goto out;
1997 }
1998
1999 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
2000 block_size, &ti->error, &pool_created);
2001 if (IS_ERR(pool)) {
2002 r = PTR_ERR(pool);
2003 goto out_free_pt;
2004 }
2005
2006 /*
2007 * 'pool_created' reflects whether this is the first table load.
2008 * Top level discard support is not allowed to be changed after
2009 * initial load. This would require a pool reload to trigger thin
2010 * device changes.
2011 */
2012 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
2013 ti->error = "Discard support cannot be disabled once enabled";
2014 r = -EINVAL;
2015 goto out_flags_changed;
2016 }
2017
2018 pt->pool = pool;
2019 pt->ti = ti;
2020 pt->metadata_dev = metadata_dev;
2021 pt->data_dev = data_dev;
2022 pt->low_water_blocks = low_water_blocks;
2023 pt->pf = pf;
2024 ti->num_flush_requests = 1;
2025 /*
2026 * Only need to enable discards if the pool should pass
2027 * them down to the data device. The thin device's discard
2028 * processing will cause mappings to be removed from the btree.
2029 */
2030 if (pf.discard_enabled && pf.discard_passdown) {
2031 ti->num_discard_requests = 1;
2032 /*
2033 * Setting 'discards_supported' circumvents the normal
2034 * stacking of discard limits (this keeps the pool and
2035 * thin devices' discard limits consistent).
2036 */
2037 ti->discards_supported = 1;
2038 }
2039 ti->private = pt;
2040
2041 pt->callbacks.congested_fn = pool_is_congested;
2042 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2043
2044 mutex_unlock(&dm_thin_pool_table.mutex);
2045
2046 return 0;
2047
2048out_flags_changed:
2049 __pool_dec(pool);
2050out_free_pt:
2051 kfree(pt);
2052out:
2053 dm_put_device(ti, data_dev);
2054out_metadata:
2055 dm_put_device(ti, metadata_dev);
2056out_unlock:
2057 mutex_unlock(&dm_thin_pool_table.mutex);
2058
2059 return r;
2060}
2061
2062static int pool_map(struct dm_target *ti, struct bio *bio,
2063 union map_info *map_context)
2064{
2065 int r;
2066 struct pool_c *pt = ti->private;
2067 struct pool *pool = pt->pool;
2068 unsigned long flags;
2069
2070 /*
2071 * As this is a singleton target, ti->begin is always zero.
2072 */
2073 spin_lock_irqsave(&pool->lock, flags);
2074 bio->bi_bdev = pt->data_dev->bdev;
2075 r = DM_MAPIO_REMAPPED;
2076 spin_unlock_irqrestore(&pool->lock, flags);
2077
2078 return r;
2079}
2080
2081/*
2082 * Retrieves the number of blocks of the data device from
2083 * the superblock and compares it to the actual device size,
2084 * thus resizing the data device in case it has grown.
2085 *
2086 * This both copes with opening preallocated data devices in the ctr
2087 * being followed by a resume
2088 * -and-
2089 * calling the resume method individually after userspace has
2090 * grown the data device in reaction to a table event.
2091 */
2092static int pool_preresume(struct dm_target *ti)
2093{
2094 int r;
2095 struct pool_c *pt = ti->private;
2096 struct pool *pool = pt->pool;
2097 dm_block_t data_size, sb_data_size;
2098
2099 /*
2100 * Take control of the pool object.
2101 */
2102 r = bind_control_target(pool, ti);
2103 if (r)
2104 return r;
2105
2106 data_size = ti->len >> pool->block_shift;
2107 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2108 if (r) {
2109 DMERR("failed to retrieve data device size");
2110 return r;
2111 }
2112
2113 if (data_size < sb_data_size) {
2114 DMERR("pool target too small, is %llu blocks (expected %llu)",
2115 data_size, sb_data_size);
2116 return -EINVAL;
2117
2118 } else if (data_size > sb_data_size) {
2119 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2120 if (r) {
2121 DMERR("failed to resize data device");
2122 return r;
2123 }
2124
2125 r = dm_pool_commit_metadata(pool->pmd);
2126 if (r) {
2127 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2128 __func__, r);
2129 return r;
2130 }
2131 }
2132
2133 return 0;
2134}
2135
2136static void pool_resume(struct dm_target *ti)
2137{
2138 struct pool_c *pt = ti->private;
2139 struct pool *pool = pt->pool;
2140 unsigned long flags;
2141
2142 spin_lock_irqsave(&pool->lock, flags);
2143 pool->low_water_triggered = 0;
2144 pool->no_free_space = 0;
2145 __requeue_bios(pool);
2146 spin_unlock_irqrestore(&pool->lock, flags);
2147
2148 do_waker(&pool->waker.work);
2149}
2150
2151static void pool_postsuspend(struct dm_target *ti)
2152{
2153 int r;
2154 struct pool_c *pt = ti->private;
2155 struct pool *pool = pt->pool;
2156
2157 cancel_delayed_work(&pool->waker);
2158 flush_workqueue(pool->wq);
2159
2160 r = dm_pool_commit_metadata(pool->pmd);
2161 if (r < 0) {
2162 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2163 __func__, r);
2164 /* FIXME: invalidate device? error the next FUA or FLUSH bio ?*/
2165 }
2166}
2167
2168static int check_arg_count(unsigned argc, unsigned args_required)
2169{
2170 if (argc != args_required) {
2171 DMWARN("Message received with %u arguments instead of %u.",
2172 argc, args_required);
2173 return -EINVAL;
2174 }
2175
2176 return 0;
2177}
2178
2179static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2180{
2181 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2182 *dev_id <= MAX_DEV_ID)
2183 return 0;
2184
2185 if (warning)
2186 DMWARN("Message received with invalid device id: %s", arg);
2187
2188 return -EINVAL;
2189}
2190
2191static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2192{
2193 dm_thin_id dev_id;
2194 int r;
2195
2196 r = check_arg_count(argc, 2);
2197 if (r)
2198 return r;
2199
2200 r = read_dev_id(argv[1], &dev_id, 1);
2201 if (r)
2202 return r;
2203
2204 r = dm_pool_create_thin(pool->pmd, dev_id);
2205 if (r) {
2206 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2207 argv[1]);
2208 return r;
2209 }
2210
2211 return 0;
2212}
2213
2214static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2215{
2216 dm_thin_id dev_id;
2217 dm_thin_id origin_dev_id;
2218 int r;
2219
2220 r = check_arg_count(argc, 3);
2221 if (r)
2222 return r;
2223
2224 r = read_dev_id(argv[1], &dev_id, 1);
2225 if (r)
2226 return r;
2227
2228 r = read_dev_id(argv[2], &origin_dev_id, 1);
2229 if (r)
2230 return r;
2231
2232 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2233 if (r) {
2234 DMWARN("Creation of new snapshot %s of device %s failed.",
2235 argv[1], argv[2]);
2236 return r;
2237 }
2238
2239 return 0;
2240}
2241
2242static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2243{
2244 dm_thin_id dev_id;
2245 int r;
2246
2247 r = check_arg_count(argc, 2);
2248 if (r)
2249 return r;
2250
2251 r = read_dev_id(argv[1], &dev_id, 1);
2252 if (r)
2253 return r;
2254
2255 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2256 if (r)
2257 DMWARN("Deletion of thin device %s failed.", argv[1]);
2258
2259 return r;
2260}
2261
2262static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2263{
2264 dm_thin_id old_id, new_id;
2265 int r;
2266
2267 r = check_arg_count(argc, 3);
2268 if (r)
2269 return r;
2270
2271 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2272 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2273 return -EINVAL;
2274 }
2275
2276 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2277 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2278 return -EINVAL;
2279 }
2280
2281 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2282 if (r) {
2283 DMWARN("Failed to change transaction id from %s to %s.",
2284 argv[1], argv[2]);
2285 return r;
2286 }
2287
2288 return 0;
2289}
2290
2291static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2292{
2293 int r;
2294
2295 r = check_arg_count(argc, 1);
2296 if (r)
2297 return r;
2298
2299 r = dm_pool_commit_metadata(pool->pmd);
2300 if (r) {
2301 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2302 __func__, r);
2303 return r;
2304 }
2305
2306 r = dm_pool_reserve_metadata_snap(pool->pmd);
2307 if (r)
2308 DMWARN("reserve_metadata_snap message failed.");
2309
2310 return r;
2311}
2312
2313static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2314{
2315 int r;
2316
2317 r = check_arg_count(argc, 1);
2318 if (r)
2319 return r;
2320
2321 r = dm_pool_release_metadata_snap(pool->pmd);
2322 if (r)
2323 DMWARN("release_metadata_snap message failed.");
2324
2325 return r;
2326}
2327
2328/*
2329 * Messages supported:
2330 * create_thin <dev_id>
2331 * create_snap <dev_id> <origin_id>
2332 * delete <dev_id>
2333 * trim <dev_id> <new_size_in_sectors>
2334 * set_transaction_id <current_trans_id> <new_trans_id>
2335 * reserve_metadata_snap
2336 * release_metadata_snap
2337 */
2338static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2339{
2340 int r = -EINVAL;
2341 struct pool_c *pt = ti->private;
2342 struct pool *pool = pt->pool;
2343
2344 if (!strcasecmp(argv[0], "create_thin"))
2345 r = process_create_thin_mesg(argc, argv, pool);
2346
2347 else if (!strcasecmp(argv[0], "create_snap"))
2348 r = process_create_snap_mesg(argc, argv, pool);
2349
2350 else if (!strcasecmp(argv[0], "delete"))
2351 r = process_delete_mesg(argc, argv, pool);
2352
2353 else if (!strcasecmp(argv[0], "set_transaction_id"))
2354 r = process_set_transaction_id_mesg(argc, argv, pool);
2355
2356 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
2357 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
2358
2359 else if (!strcasecmp(argv[0], "release_metadata_snap"))
2360 r = process_release_metadata_snap_mesg(argc, argv, pool);
2361
2362 else
2363 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2364
2365 if (!r) {
2366 r = dm_pool_commit_metadata(pool->pmd);
2367 if (r)
2368 DMERR("%s message: dm_pool_commit_metadata() failed, error = %d",
2369 argv[0], r);
2370 }
2371
2372 return r;
2373}
2374
2375/*
2376 * Status line is:
2377 * <transaction id> <used metadata sectors>/<total metadata sectors>
2378 * <used data sectors>/<total data sectors> <held metadata root>
2379 */
2380static int pool_status(struct dm_target *ti, status_type_t type,
2381 char *result, unsigned maxlen)
2382{
2383 int r, count;
2384 unsigned sz = 0;
2385 uint64_t transaction_id;
2386 dm_block_t nr_free_blocks_data;
2387 dm_block_t nr_free_blocks_metadata;
2388 dm_block_t nr_blocks_data;
2389 dm_block_t nr_blocks_metadata;
2390 dm_block_t held_root;
2391 char buf[BDEVNAME_SIZE];
2392 char buf2[BDEVNAME_SIZE];
2393 struct pool_c *pt = ti->private;
2394 struct pool *pool = pt->pool;
2395
2396 switch (type) {
2397 case STATUSTYPE_INFO:
2398 r = dm_pool_get_metadata_transaction_id(pool->pmd,
2399 &transaction_id);
2400 if (r)
2401 return r;
2402
2403 r = dm_pool_get_free_metadata_block_count(pool->pmd,
2404 &nr_free_blocks_metadata);
2405 if (r)
2406 return r;
2407
2408 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2409 if (r)
2410 return r;
2411
2412 r = dm_pool_get_free_block_count(pool->pmd,
2413 &nr_free_blocks_data);
2414 if (r)
2415 return r;
2416
2417 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2418 if (r)
2419 return r;
2420
2421 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
2422 if (r)
2423 return r;
2424
2425 DMEMIT("%llu %llu/%llu %llu/%llu ",
2426 (unsigned long long)transaction_id,
2427 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2428 (unsigned long long)nr_blocks_metadata,
2429 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2430 (unsigned long long)nr_blocks_data);
2431
2432 if (held_root)
2433 DMEMIT("%llu", held_root);
2434 else
2435 DMEMIT("-");
2436
2437 break;
2438
2439 case STATUSTYPE_TABLE:
2440 DMEMIT("%s %s %lu %llu ",
2441 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2442 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2443 (unsigned long)pool->sectors_per_block,
2444 (unsigned long long)pt->low_water_blocks);
2445
2446 count = !pool->pf.zero_new_blocks + !pool->pf.discard_enabled +
2447 !pt->pf.discard_passdown;
2448 DMEMIT("%u ", count);
2449
2450 if (!pool->pf.zero_new_blocks)
2451 DMEMIT("skip_block_zeroing ");
2452
2453 if (!pool->pf.discard_enabled)
2454 DMEMIT("ignore_discard ");
2455
2456 if (!pt->pf.discard_passdown)
2457 DMEMIT("no_discard_passdown ");
2458
2459 break;
2460 }
2461
2462 return 0;
2463}
2464
2465static int pool_iterate_devices(struct dm_target *ti,
2466 iterate_devices_callout_fn fn, void *data)
2467{
2468 struct pool_c *pt = ti->private;
2469
2470 return fn(ti, pt->data_dev, 0, ti->len, data);
2471}
2472
2473static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2474 struct bio_vec *biovec, int max_size)
2475{
2476 struct pool_c *pt = ti->private;
2477 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2478
2479 if (!q->merge_bvec_fn)
2480 return max_size;
2481
2482 bvm->bi_bdev = pt->data_dev->bdev;
2483
2484 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2485}
2486
2487static void set_discard_limits(struct pool *pool, struct queue_limits *limits)
2488{
2489 /*
2490 * FIXME: these limits may be incompatible with the pool's data device
2491 */
2492 limits->max_discard_sectors = pool->sectors_per_block;
2493
2494 /*
2495 * This is just a hint, and not enforced. We have to cope with
2496 * bios that overlap 2 blocks.
2497 */
2498 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
2499 limits->discard_zeroes_data = pool->pf.zero_new_blocks;
2500}
2501
2502static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2503{
2504 struct pool_c *pt = ti->private;
2505 struct pool *pool = pt->pool;
2506
2507 blk_limits_io_min(limits, 0);
2508 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2509 if (pool->pf.discard_enabled)
2510 set_discard_limits(pool, limits);
2511}
2512
2513static struct target_type pool_target = {
2514 .name = "thin-pool",
2515 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2516 DM_TARGET_IMMUTABLE,
2517 .version = {1, 2, 0},
2518 .module = THIS_MODULE,
2519 .ctr = pool_ctr,
2520 .dtr = pool_dtr,
2521 .map = pool_map,
2522 .postsuspend = pool_postsuspend,
2523 .preresume = pool_preresume,
2524 .resume = pool_resume,
2525 .message = pool_message,
2526 .status = pool_status,
2527 .merge = pool_merge,
2528 .iterate_devices = pool_iterate_devices,
2529 .io_hints = pool_io_hints,
2530};
2531
2532/*----------------------------------------------------------------
2533 * Thin target methods
2534 *--------------------------------------------------------------*/
2535static void thin_dtr(struct dm_target *ti)
2536{
2537 struct thin_c *tc = ti->private;
2538
2539 mutex_lock(&dm_thin_pool_table.mutex);
2540
2541 __pool_dec(tc->pool);
2542 dm_pool_close_thin_device(tc->td);
2543 dm_put_device(ti, tc->pool_dev);
2544 if (tc->origin_dev)
2545 dm_put_device(ti, tc->origin_dev);
2546 kfree(tc);
2547
2548 mutex_unlock(&dm_thin_pool_table.mutex);
2549}
2550
2551/*
2552 * Thin target parameters:
2553 *
2554 * <pool_dev> <dev_id> [origin_dev]
2555 *
2556 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2557 * dev_id: the internal device identifier
2558 * origin_dev: a device external to the pool that should act as the origin
2559 *
2560 * If the pool device has discards disabled, they get disabled for the thin
2561 * device as well.
2562 */
2563static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2564{
2565 int r;
2566 struct thin_c *tc;
2567 struct dm_dev *pool_dev, *origin_dev;
2568 struct mapped_device *pool_md;
2569
2570 mutex_lock(&dm_thin_pool_table.mutex);
2571
2572 if (argc != 2 && argc != 3) {
2573 ti->error = "Invalid argument count";
2574 r = -EINVAL;
2575 goto out_unlock;
2576 }
2577
2578 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2579 if (!tc) {
2580 ti->error = "Out of memory";
2581 r = -ENOMEM;
2582 goto out_unlock;
2583 }
2584
2585 if (argc == 3) {
2586 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
2587 if (r) {
2588 ti->error = "Error opening origin device";
2589 goto bad_origin_dev;
2590 }
2591 tc->origin_dev = origin_dev;
2592 }
2593
2594 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2595 if (r) {
2596 ti->error = "Error opening pool device";
2597 goto bad_pool_dev;
2598 }
2599 tc->pool_dev = pool_dev;
2600
2601 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2602 ti->error = "Invalid device id";
2603 r = -EINVAL;
2604 goto bad_common;
2605 }
2606
2607 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2608 if (!pool_md) {
2609 ti->error = "Couldn't get pool mapped device";
2610 r = -EINVAL;
2611 goto bad_common;
2612 }
2613
2614 tc->pool = __pool_table_lookup(pool_md);
2615 if (!tc->pool) {
2616 ti->error = "Couldn't find pool object";
2617 r = -EINVAL;
2618 goto bad_pool_lookup;
2619 }
2620 __pool_inc(tc->pool);
2621
2622 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
2623 if (r) {
2624 ti->error = "Couldn't open thin internal device";
2625 goto bad_thin_open;
2626 }
2627
2628 ti->split_io = tc->pool->sectors_per_block;
2629 ti->num_flush_requests = 1;
2630
2631 /* In case the pool supports discards, pass them on. */
2632 if (tc->pool->pf.discard_enabled) {
2633 ti->discards_supported = 1;
2634 ti->num_discard_requests = 1;
2635 ti->discard_zeroes_data_unsupported = 1;
2636 }
2637
2638 dm_put(pool_md);
2639
2640 mutex_unlock(&dm_thin_pool_table.mutex);
2641
2642 return 0;
2643
2644bad_thin_open:
2645 __pool_dec(tc->pool);
2646bad_pool_lookup:
2647 dm_put(pool_md);
2648bad_common:
2649 dm_put_device(ti, tc->pool_dev);
2650bad_pool_dev:
2651 if (tc->origin_dev)
2652 dm_put_device(ti, tc->origin_dev);
2653bad_origin_dev:
2654 kfree(tc);
2655out_unlock:
2656 mutex_unlock(&dm_thin_pool_table.mutex);
2657
2658 return r;
2659}
2660
2661static int thin_map(struct dm_target *ti, struct bio *bio,
2662 union map_info *map_context)
2663{
2664 bio->bi_sector = dm_target_offset(ti, bio->bi_sector);
2665
2666 return thin_bio_map(ti, bio, map_context);
2667}
2668
2669static int thin_endio(struct dm_target *ti,
2670 struct bio *bio, int err,
2671 union map_info *map_context)
2672{
2673 unsigned long flags;
2674 struct dm_thin_endio_hook *h = map_context->ptr;
2675 struct list_head work;
2676 struct dm_thin_new_mapping *m, *tmp;
2677 struct pool *pool = h->tc->pool;
2678
2679 if (h->shared_read_entry) {
2680 INIT_LIST_HEAD(&work);
2681 ds_dec(h->shared_read_entry, &work);
2682
2683 spin_lock_irqsave(&pool->lock, flags);
2684 list_for_each_entry_safe(m, tmp, &work, list) {
2685 list_del(&m->list);
2686 m->quiesced = 1;
2687 __maybe_add_mapping(m);
2688 }
2689 spin_unlock_irqrestore(&pool->lock, flags);
2690 }
2691
2692 if (h->all_io_entry) {
2693 INIT_LIST_HEAD(&work);
2694 ds_dec(h->all_io_entry, &work);
2695 spin_lock_irqsave(&pool->lock, flags);
2696 list_for_each_entry_safe(m, tmp, &work, list)
2697 list_add(&m->list, &pool->prepared_discards);
2698 spin_unlock_irqrestore(&pool->lock, flags);
2699 }
2700
2701 mempool_free(h, pool->endio_hook_pool);
2702
2703 return 0;
2704}
2705
2706static void thin_postsuspend(struct dm_target *ti)
2707{
2708 if (dm_noflush_suspending(ti))
2709 requeue_io((struct thin_c *)ti->private);
2710}
2711
2712/*
2713 * <nr mapped sectors> <highest mapped sector>
2714 */
2715static int thin_status(struct dm_target *ti, status_type_t type,
2716 char *result, unsigned maxlen)
2717{
2718 int r;
2719 ssize_t sz = 0;
2720 dm_block_t mapped, highest;
2721 char buf[BDEVNAME_SIZE];
2722 struct thin_c *tc = ti->private;
2723
2724 if (!tc->td)
2725 DMEMIT("-");
2726 else {
2727 switch (type) {
2728 case STATUSTYPE_INFO:
2729 r = dm_thin_get_mapped_count(tc->td, &mapped);
2730 if (r)
2731 return r;
2732
2733 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
2734 if (r < 0)
2735 return r;
2736
2737 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
2738 if (r)
2739 DMEMIT("%llu", ((highest + 1) *
2740 tc->pool->sectors_per_block) - 1);
2741 else
2742 DMEMIT("-");
2743 break;
2744
2745 case STATUSTYPE_TABLE:
2746 DMEMIT("%s %lu",
2747 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
2748 (unsigned long) tc->dev_id);
2749 if (tc->origin_dev)
2750 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
2751 break;
2752 }
2753 }
2754
2755 return 0;
2756}
2757
2758static int thin_iterate_devices(struct dm_target *ti,
2759 iterate_devices_callout_fn fn, void *data)
2760{
2761 dm_block_t blocks;
2762 struct thin_c *tc = ti->private;
2763
2764 /*
2765 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2766 * we follow a more convoluted path through to the pool's target.
2767 */
2768 if (!tc->pool->ti)
2769 return 0; /* nothing is bound */
2770
2771 blocks = tc->pool->ti->len >> tc->pool->block_shift;
2772 if (blocks)
2773 return fn(ti, tc->pool_dev, 0, tc->pool->sectors_per_block * blocks, data);
2774
2775 return 0;
2776}
2777
2778static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
2779{
2780 struct thin_c *tc = ti->private;
2781 struct pool *pool = tc->pool;
2782
2783 blk_limits_io_min(limits, 0);
2784 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2785 set_discard_limits(pool, limits);
2786}
2787
2788static struct target_type thin_target = {
2789 .name = "thin",
2790 .version = {1, 1, 0},
2791 .module = THIS_MODULE,
2792 .ctr = thin_ctr,
2793 .dtr = thin_dtr,
2794 .map = thin_map,
2795 .end_io = thin_endio,
2796 .postsuspend = thin_postsuspend,
2797 .status = thin_status,
2798 .iterate_devices = thin_iterate_devices,
2799 .io_hints = thin_io_hints,
2800};
2801
2802/*----------------------------------------------------------------*/
2803
2804static int __init dm_thin_init(void)
2805{
2806 int r;
2807
2808 pool_table_init();
2809
2810 r = dm_register_target(&thin_target);
2811 if (r)
2812 return r;
2813
2814 r = dm_register_target(&pool_target);
2815 if (r)
2816 goto bad_pool_target;
2817
2818 r = -ENOMEM;
2819
2820 _cell_cache = KMEM_CACHE(dm_bio_prison_cell, 0);
2821 if (!_cell_cache)
2822 goto bad_cell_cache;
2823
2824 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
2825 if (!_new_mapping_cache)
2826 goto bad_new_mapping_cache;
2827
2828 _endio_hook_cache = KMEM_CACHE(dm_thin_endio_hook, 0);
2829 if (!_endio_hook_cache)
2830 goto bad_endio_hook_cache;
2831
2832 return 0;
2833
2834bad_endio_hook_cache:
2835 kmem_cache_destroy(_new_mapping_cache);
2836bad_new_mapping_cache:
2837 kmem_cache_destroy(_cell_cache);
2838bad_cell_cache:
2839 dm_unregister_target(&pool_target);
2840bad_pool_target:
2841 dm_unregister_target(&thin_target);
2842
2843 return r;
2844}
2845
2846static void dm_thin_exit(void)
2847{
2848 dm_unregister_target(&thin_target);
2849 dm_unregister_target(&pool_target);
2850
2851 kmem_cache_destroy(_cell_cache);
2852 kmem_cache_destroy(_new_mapping_cache);
2853 kmem_cache_destroy(_endio_hook_cache);
2854}
2855
2856module_init(dm_thin_init);
2857module_exit(dm_thin_exit);
2858
2859MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
2860MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2861MODULE_LICENSE("GPL");
1/*
2 * Copyright (C) 2011-2012 Red Hat UK.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-thin-metadata.h"
8#include "dm-bio-prison-v1.h"
9#include "dm.h"
10
11#include <linux/device-mapper.h>
12#include <linux/dm-io.h>
13#include <linux/dm-kcopyd.h>
14#include <linux/jiffies.h>
15#include <linux/log2.h>
16#include <linux/list.h>
17#include <linux/rculist.h>
18#include <linux/init.h>
19#include <linux/module.h>
20#include <linux/slab.h>
21#include <linux/vmalloc.h>
22#include <linux/sort.h>
23#include <linux/rbtree.h>
24
25#define DM_MSG_PREFIX "thin"
26
27/*
28 * Tunable constants
29 */
30#define ENDIO_HOOK_POOL_SIZE 1024
31#define MAPPING_POOL_SIZE 1024
32#define COMMIT_PERIOD HZ
33#define NO_SPACE_TIMEOUT_SECS 60
34
35static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
36
37DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
38 "A percentage of time allocated for copy on write");
39
40/*
41 * The block size of the device holding pool data must be
42 * between 64KB and 1GB.
43 */
44#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
45#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
46
47/*
48 * Device id is restricted to 24 bits.
49 */
50#define MAX_DEV_ID ((1 << 24) - 1)
51
52/*
53 * How do we handle breaking sharing of data blocks?
54 * =================================================
55 *
56 * We use a standard copy-on-write btree to store the mappings for the
57 * devices (note I'm talking about copy-on-write of the metadata here, not
58 * the data). When you take an internal snapshot you clone the root node
59 * of the origin btree. After this there is no concept of an origin or a
60 * snapshot. They are just two device trees that happen to point to the
61 * same data blocks.
62 *
63 * When we get a write in we decide if it's to a shared data block using
64 * some timestamp magic. If it is, we have to break sharing.
65 *
66 * Let's say we write to a shared block in what was the origin. The
67 * steps are:
68 *
69 * i) plug io further to this physical block. (see bio_prison code).
70 *
71 * ii) quiesce any read io to that shared data block. Obviously
72 * including all devices that share this block. (see dm_deferred_set code)
73 *
74 * iii) copy the data block to a newly allocate block. This step can be
75 * missed out if the io covers the block. (schedule_copy).
76 *
77 * iv) insert the new mapping into the origin's btree
78 * (process_prepared_mapping). This act of inserting breaks some
79 * sharing of btree nodes between the two devices. Breaking sharing only
80 * effects the btree of that specific device. Btrees for the other
81 * devices that share the block never change. The btree for the origin
82 * device as it was after the last commit is untouched, ie. we're using
83 * persistent data structures in the functional programming sense.
84 *
85 * v) unplug io to this physical block, including the io that triggered
86 * the breaking of sharing.
87 *
88 * Steps (ii) and (iii) occur in parallel.
89 *
90 * The metadata _doesn't_ need to be committed before the io continues. We
91 * get away with this because the io is always written to a _new_ block.
92 * If there's a crash, then:
93 *
94 * - The origin mapping will point to the old origin block (the shared
95 * one). This will contain the data as it was before the io that triggered
96 * the breaking of sharing came in.
97 *
98 * - The snap mapping still points to the old block. As it would after
99 * the commit.
100 *
101 * The downside of this scheme is the timestamp magic isn't perfect, and
102 * will continue to think that data block in the snapshot device is shared
103 * even after the write to the origin has broken sharing. I suspect data
104 * blocks will typically be shared by many different devices, so we're
105 * breaking sharing n + 1 times, rather than n, where n is the number of
106 * devices that reference this data block. At the moment I think the
107 * benefits far, far outweigh the disadvantages.
108 */
109
110/*----------------------------------------------------------------*/
111
112/*
113 * Key building.
114 */
115enum lock_space {
116 VIRTUAL,
117 PHYSICAL
118};
119
120static void build_key(struct dm_thin_device *td, enum lock_space ls,
121 dm_block_t b, dm_block_t e, struct dm_cell_key *key)
122{
123 key->virtual = (ls == VIRTUAL);
124 key->dev = dm_thin_dev_id(td);
125 key->block_begin = b;
126 key->block_end = e;
127}
128
129static void build_data_key(struct dm_thin_device *td, dm_block_t b,
130 struct dm_cell_key *key)
131{
132 build_key(td, PHYSICAL, b, b + 1llu, key);
133}
134
135static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
136 struct dm_cell_key *key)
137{
138 build_key(td, VIRTUAL, b, b + 1llu, key);
139}
140
141/*----------------------------------------------------------------*/
142
143#define THROTTLE_THRESHOLD (1 * HZ)
144
145struct throttle {
146 struct rw_semaphore lock;
147 unsigned long threshold;
148 bool throttle_applied;
149};
150
151static void throttle_init(struct throttle *t)
152{
153 init_rwsem(&t->lock);
154 t->throttle_applied = false;
155}
156
157static void throttle_work_start(struct throttle *t)
158{
159 t->threshold = jiffies + THROTTLE_THRESHOLD;
160}
161
162static void throttle_work_update(struct throttle *t)
163{
164 if (!t->throttle_applied && jiffies > t->threshold) {
165 down_write(&t->lock);
166 t->throttle_applied = true;
167 }
168}
169
170static void throttle_work_complete(struct throttle *t)
171{
172 if (t->throttle_applied) {
173 t->throttle_applied = false;
174 up_write(&t->lock);
175 }
176}
177
178static void throttle_lock(struct throttle *t)
179{
180 down_read(&t->lock);
181}
182
183static void throttle_unlock(struct throttle *t)
184{
185 up_read(&t->lock);
186}
187
188/*----------------------------------------------------------------*/
189
190/*
191 * A pool device ties together a metadata device and a data device. It
192 * also provides the interface for creating and destroying internal
193 * devices.
194 */
195struct dm_thin_new_mapping;
196
197/*
198 * The pool runs in various modes. Ordered in degraded order for comparisons.
199 */
200enum pool_mode {
201 PM_WRITE, /* metadata may be changed */
202 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
203
204 /*
205 * Like READ_ONLY, except may switch back to WRITE on metadata resize. Reported as READ_ONLY.
206 */
207 PM_OUT_OF_METADATA_SPACE,
208 PM_READ_ONLY, /* metadata may not be changed */
209
210 PM_FAIL, /* all I/O fails */
211};
212
213struct pool_features {
214 enum pool_mode mode;
215
216 bool zero_new_blocks:1;
217 bool discard_enabled:1;
218 bool discard_passdown:1;
219 bool error_if_no_space:1;
220};
221
222struct thin_c;
223typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
224typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell);
225typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
226
227#define CELL_SORT_ARRAY_SIZE 8192
228
229struct pool {
230 struct list_head list;
231 struct dm_target *ti; /* Only set if a pool target is bound */
232
233 struct mapped_device *pool_md;
234 struct block_device *data_dev;
235 struct block_device *md_dev;
236 struct dm_pool_metadata *pmd;
237
238 dm_block_t low_water_blocks;
239 uint32_t sectors_per_block;
240 int sectors_per_block_shift;
241
242 struct pool_features pf;
243 bool low_water_triggered:1; /* A dm event has been sent */
244 bool suspended:1;
245 bool out_of_data_space:1;
246
247 struct dm_bio_prison *prison;
248 struct dm_kcopyd_client *copier;
249
250 struct work_struct worker;
251 struct workqueue_struct *wq;
252 struct throttle throttle;
253 struct delayed_work waker;
254 struct delayed_work no_space_timeout;
255
256 unsigned long last_commit_jiffies;
257 unsigned ref_count;
258
259 spinlock_t lock;
260 struct bio_list deferred_flush_bios;
261 struct bio_list deferred_flush_completions;
262 struct list_head prepared_mappings;
263 struct list_head prepared_discards;
264 struct list_head prepared_discards_pt2;
265 struct list_head active_thins;
266
267 struct dm_deferred_set *shared_read_ds;
268 struct dm_deferred_set *all_io_ds;
269
270 struct dm_thin_new_mapping *next_mapping;
271
272 process_bio_fn process_bio;
273 process_bio_fn process_discard;
274
275 process_cell_fn process_cell;
276 process_cell_fn process_discard_cell;
277
278 process_mapping_fn process_prepared_mapping;
279 process_mapping_fn process_prepared_discard;
280 process_mapping_fn process_prepared_discard_pt2;
281
282 struct dm_bio_prison_cell **cell_sort_array;
283
284 mempool_t mapping_pool;
285
286 struct bio flush_bio;
287};
288
289static void metadata_operation_failed(struct pool *pool, const char *op, int r);
290
291static enum pool_mode get_pool_mode(struct pool *pool)
292{
293 return pool->pf.mode;
294}
295
296static void notify_of_pool_mode_change(struct pool *pool)
297{
298 const char *descs[] = {
299 "write",
300 "out-of-data-space",
301 "read-only",
302 "read-only",
303 "fail"
304 };
305 const char *extra_desc = NULL;
306 enum pool_mode mode = get_pool_mode(pool);
307
308 if (mode == PM_OUT_OF_DATA_SPACE) {
309 if (!pool->pf.error_if_no_space)
310 extra_desc = " (queue IO)";
311 else
312 extra_desc = " (error IO)";
313 }
314
315 dm_table_event(pool->ti->table);
316 DMINFO("%s: switching pool to %s%s mode",
317 dm_device_name(pool->pool_md),
318 descs[(int)mode], extra_desc ? : "");
319}
320
321/*
322 * Target context for a pool.
323 */
324struct pool_c {
325 struct dm_target *ti;
326 struct pool *pool;
327 struct dm_dev *data_dev;
328 struct dm_dev *metadata_dev;
329
330 dm_block_t low_water_blocks;
331 struct pool_features requested_pf; /* Features requested during table load */
332 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
333};
334
335/*
336 * Target context for a thin.
337 */
338struct thin_c {
339 struct list_head list;
340 struct dm_dev *pool_dev;
341 struct dm_dev *origin_dev;
342 sector_t origin_size;
343 dm_thin_id dev_id;
344
345 struct pool *pool;
346 struct dm_thin_device *td;
347 struct mapped_device *thin_md;
348
349 bool requeue_mode:1;
350 spinlock_t lock;
351 struct list_head deferred_cells;
352 struct bio_list deferred_bio_list;
353 struct bio_list retry_on_resume_list;
354 struct rb_root sort_bio_list; /* sorted list of deferred bios */
355
356 /*
357 * Ensures the thin is not destroyed until the worker has finished
358 * iterating the active_thins list.
359 */
360 refcount_t refcount;
361 struct completion can_destroy;
362};
363
364/*----------------------------------------------------------------*/
365
366static bool block_size_is_power_of_two(struct pool *pool)
367{
368 return pool->sectors_per_block_shift >= 0;
369}
370
371static sector_t block_to_sectors(struct pool *pool, dm_block_t b)
372{
373 return block_size_is_power_of_two(pool) ?
374 (b << pool->sectors_per_block_shift) :
375 (b * pool->sectors_per_block);
376}
377
378/*----------------------------------------------------------------*/
379
380struct discard_op {
381 struct thin_c *tc;
382 struct blk_plug plug;
383 struct bio *parent_bio;
384 struct bio *bio;
385};
386
387static void begin_discard(struct discard_op *op, struct thin_c *tc, struct bio *parent)
388{
389 BUG_ON(!parent);
390
391 op->tc = tc;
392 blk_start_plug(&op->plug);
393 op->parent_bio = parent;
394 op->bio = NULL;
395}
396
397static int issue_discard(struct discard_op *op, dm_block_t data_b, dm_block_t data_e)
398{
399 struct thin_c *tc = op->tc;
400 sector_t s = block_to_sectors(tc->pool, data_b);
401 sector_t len = block_to_sectors(tc->pool, data_e - data_b);
402
403 return __blkdev_issue_discard(tc->pool_dev->bdev, s, len,
404 GFP_NOWAIT, 0, &op->bio);
405}
406
407static void end_discard(struct discard_op *op, int r)
408{
409 if (op->bio) {
410 /*
411 * Even if one of the calls to issue_discard failed, we
412 * need to wait for the chain to complete.
413 */
414 bio_chain(op->bio, op->parent_bio);
415 bio_set_op_attrs(op->bio, REQ_OP_DISCARD, 0);
416 submit_bio(op->bio);
417 }
418
419 blk_finish_plug(&op->plug);
420
421 /*
422 * Even if r is set, there could be sub discards in flight that we
423 * need to wait for.
424 */
425 if (r && !op->parent_bio->bi_status)
426 op->parent_bio->bi_status = errno_to_blk_status(r);
427 bio_endio(op->parent_bio);
428}
429
430/*----------------------------------------------------------------*/
431
432/*
433 * wake_worker() is used when new work is queued and when pool_resume is
434 * ready to continue deferred IO processing.
435 */
436static void wake_worker(struct pool *pool)
437{
438 queue_work(pool->wq, &pool->worker);
439}
440
441/*----------------------------------------------------------------*/
442
443static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
444 struct dm_bio_prison_cell **cell_result)
445{
446 int r;
447 struct dm_bio_prison_cell *cell_prealloc;
448
449 /*
450 * Allocate a cell from the prison's mempool.
451 * This might block but it can't fail.
452 */
453 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
454
455 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
456 if (r)
457 /*
458 * We reused an old cell; we can get rid of
459 * the new one.
460 */
461 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
462
463 return r;
464}
465
466static void cell_release(struct pool *pool,
467 struct dm_bio_prison_cell *cell,
468 struct bio_list *bios)
469{
470 dm_cell_release(pool->prison, cell, bios);
471 dm_bio_prison_free_cell(pool->prison, cell);
472}
473
474static void cell_visit_release(struct pool *pool,
475 void (*fn)(void *, struct dm_bio_prison_cell *),
476 void *context,
477 struct dm_bio_prison_cell *cell)
478{
479 dm_cell_visit_release(pool->prison, fn, context, cell);
480 dm_bio_prison_free_cell(pool->prison, cell);
481}
482
483static void cell_release_no_holder(struct pool *pool,
484 struct dm_bio_prison_cell *cell,
485 struct bio_list *bios)
486{
487 dm_cell_release_no_holder(pool->prison, cell, bios);
488 dm_bio_prison_free_cell(pool->prison, cell);
489}
490
491static void cell_error_with_code(struct pool *pool,
492 struct dm_bio_prison_cell *cell, blk_status_t error_code)
493{
494 dm_cell_error(pool->prison, cell, error_code);
495 dm_bio_prison_free_cell(pool->prison, cell);
496}
497
498static blk_status_t get_pool_io_error_code(struct pool *pool)
499{
500 return pool->out_of_data_space ? BLK_STS_NOSPC : BLK_STS_IOERR;
501}
502
503static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
504{
505 cell_error_with_code(pool, cell, get_pool_io_error_code(pool));
506}
507
508static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
509{
510 cell_error_with_code(pool, cell, 0);
511}
512
513static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
514{
515 cell_error_with_code(pool, cell, BLK_STS_DM_REQUEUE);
516}
517
518/*----------------------------------------------------------------*/
519
520/*
521 * A global list of pools that uses a struct mapped_device as a key.
522 */
523static struct dm_thin_pool_table {
524 struct mutex mutex;
525 struct list_head pools;
526} dm_thin_pool_table;
527
528static void pool_table_init(void)
529{
530 mutex_init(&dm_thin_pool_table.mutex);
531 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
532}
533
534static void pool_table_exit(void)
535{
536 mutex_destroy(&dm_thin_pool_table.mutex);
537}
538
539static void __pool_table_insert(struct pool *pool)
540{
541 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
542 list_add(&pool->list, &dm_thin_pool_table.pools);
543}
544
545static void __pool_table_remove(struct pool *pool)
546{
547 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
548 list_del(&pool->list);
549}
550
551static struct pool *__pool_table_lookup(struct mapped_device *md)
552{
553 struct pool *pool = NULL, *tmp;
554
555 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
556
557 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
558 if (tmp->pool_md == md) {
559 pool = tmp;
560 break;
561 }
562 }
563
564 return pool;
565}
566
567static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
568{
569 struct pool *pool = NULL, *tmp;
570
571 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
572
573 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
574 if (tmp->md_dev == md_dev) {
575 pool = tmp;
576 break;
577 }
578 }
579
580 return pool;
581}
582
583/*----------------------------------------------------------------*/
584
585struct dm_thin_endio_hook {
586 struct thin_c *tc;
587 struct dm_deferred_entry *shared_read_entry;
588 struct dm_deferred_entry *all_io_entry;
589 struct dm_thin_new_mapping *overwrite_mapping;
590 struct rb_node rb_node;
591 struct dm_bio_prison_cell *cell;
592};
593
594static void __merge_bio_list(struct bio_list *bios, struct bio_list *master)
595{
596 bio_list_merge(bios, master);
597 bio_list_init(master);
598}
599
600static void error_bio_list(struct bio_list *bios, blk_status_t error)
601{
602 struct bio *bio;
603
604 while ((bio = bio_list_pop(bios))) {
605 bio->bi_status = error;
606 bio_endio(bio);
607 }
608}
609
610static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master,
611 blk_status_t error)
612{
613 struct bio_list bios;
614
615 bio_list_init(&bios);
616
617 spin_lock_irq(&tc->lock);
618 __merge_bio_list(&bios, master);
619 spin_unlock_irq(&tc->lock);
620
621 error_bio_list(&bios, error);
622}
623
624static void requeue_deferred_cells(struct thin_c *tc)
625{
626 struct pool *pool = tc->pool;
627 struct list_head cells;
628 struct dm_bio_prison_cell *cell, *tmp;
629
630 INIT_LIST_HEAD(&cells);
631
632 spin_lock_irq(&tc->lock);
633 list_splice_init(&tc->deferred_cells, &cells);
634 spin_unlock_irq(&tc->lock);
635
636 list_for_each_entry_safe(cell, tmp, &cells, user_list)
637 cell_requeue(pool, cell);
638}
639
640static void requeue_io(struct thin_c *tc)
641{
642 struct bio_list bios;
643
644 bio_list_init(&bios);
645
646 spin_lock_irq(&tc->lock);
647 __merge_bio_list(&bios, &tc->deferred_bio_list);
648 __merge_bio_list(&bios, &tc->retry_on_resume_list);
649 spin_unlock_irq(&tc->lock);
650
651 error_bio_list(&bios, BLK_STS_DM_REQUEUE);
652 requeue_deferred_cells(tc);
653}
654
655static void error_retry_list_with_code(struct pool *pool, blk_status_t error)
656{
657 struct thin_c *tc;
658
659 rcu_read_lock();
660 list_for_each_entry_rcu(tc, &pool->active_thins, list)
661 error_thin_bio_list(tc, &tc->retry_on_resume_list, error);
662 rcu_read_unlock();
663}
664
665static void error_retry_list(struct pool *pool)
666{
667 error_retry_list_with_code(pool, get_pool_io_error_code(pool));
668}
669
670/*
671 * This section of code contains the logic for processing a thin device's IO.
672 * Much of the code depends on pool object resources (lists, workqueues, etc)
673 * but most is exclusively called from the thin target rather than the thin-pool
674 * target.
675 */
676
677static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
678{
679 struct pool *pool = tc->pool;
680 sector_t block_nr = bio->bi_iter.bi_sector;
681
682 if (block_size_is_power_of_two(pool))
683 block_nr >>= pool->sectors_per_block_shift;
684 else
685 (void) sector_div(block_nr, pool->sectors_per_block);
686
687 return block_nr;
688}
689
690/*
691 * Returns the _complete_ blocks that this bio covers.
692 */
693static void get_bio_block_range(struct thin_c *tc, struct bio *bio,
694 dm_block_t *begin, dm_block_t *end)
695{
696 struct pool *pool = tc->pool;
697 sector_t b = bio->bi_iter.bi_sector;
698 sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT);
699
700 b += pool->sectors_per_block - 1ull; /* so we round up */
701
702 if (block_size_is_power_of_two(pool)) {
703 b >>= pool->sectors_per_block_shift;
704 e >>= pool->sectors_per_block_shift;
705 } else {
706 (void) sector_div(b, pool->sectors_per_block);
707 (void) sector_div(e, pool->sectors_per_block);
708 }
709
710 if (e < b)
711 /* Can happen if the bio is within a single block. */
712 e = b;
713
714 *begin = b;
715 *end = e;
716}
717
718static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
719{
720 struct pool *pool = tc->pool;
721 sector_t bi_sector = bio->bi_iter.bi_sector;
722
723 bio_set_dev(bio, tc->pool_dev->bdev);
724 if (block_size_is_power_of_two(pool))
725 bio->bi_iter.bi_sector =
726 (block << pool->sectors_per_block_shift) |
727 (bi_sector & (pool->sectors_per_block - 1));
728 else
729 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
730 sector_div(bi_sector, pool->sectors_per_block);
731}
732
733static void remap_to_origin(struct thin_c *tc, struct bio *bio)
734{
735 bio_set_dev(bio, tc->origin_dev->bdev);
736}
737
738static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
739{
740 return op_is_flush(bio->bi_opf) &&
741 dm_thin_changed_this_transaction(tc->td);
742}
743
744static void inc_all_io_entry(struct pool *pool, struct bio *bio)
745{
746 struct dm_thin_endio_hook *h;
747
748 if (bio_op(bio) == REQ_OP_DISCARD)
749 return;
750
751 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
752 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
753}
754
755static void issue(struct thin_c *tc, struct bio *bio)
756{
757 struct pool *pool = tc->pool;
758
759 if (!bio_triggers_commit(tc, bio)) {
760 submit_bio_noacct(bio);
761 return;
762 }
763
764 /*
765 * Complete bio with an error if earlier I/O caused changes to
766 * the metadata that can't be committed e.g, due to I/O errors
767 * on the metadata device.
768 */
769 if (dm_thin_aborted_changes(tc->td)) {
770 bio_io_error(bio);
771 return;
772 }
773
774 /*
775 * Batch together any bios that trigger commits and then issue a
776 * single commit for them in process_deferred_bios().
777 */
778 spin_lock_irq(&pool->lock);
779 bio_list_add(&pool->deferred_flush_bios, bio);
780 spin_unlock_irq(&pool->lock);
781}
782
783static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
784{
785 remap_to_origin(tc, bio);
786 issue(tc, bio);
787}
788
789static void remap_and_issue(struct thin_c *tc, struct bio *bio,
790 dm_block_t block)
791{
792 remap(tc, bio, block);
793 issue(tc, bio);
794}
795
796/*----------------------------------------------------------------*/
797
798/*
799 * Bio endio functions.
800 */
801struct dm_thin_new_mapping {
802 struct list_head list;
803
804 bool pass_discard:1;
805 bool maybe_shared:1;
806
807 /*
808 * Track quiescing, copying and zeroing preparation actions. When this
809 * counter hits zero the block is prepared and can be inserted into the
810 * btree.
811 */
812 atomic_t prepare_actions;
813
814 blk_status_t status;
815 struct thin_c *tc;
816 dm_block_t virt_begin, virt_end;
817 dm_block_t data_block;
818 struct dm_bio_prison_cell *cell;
819
820 /*
821 * If the bio covers the whole area of a block then we can avoid
822 * zeroing or copying. Instead this bio is hooked. The bio will
823 * still be in the cell, so care has to be taken to avoid issuing
824 * the bio twice.
825 */
826 struct bio *bio;
827 bio_end_io_t *saved_bi_end_io;
828};
829
830static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
831{
832 struct pool *pool = m->tc->pool;
833
834 if (atomic_dec_and_test(&m->prepare_actions)) {
835 list_add_tail(&m->list, &pool->prepared_mappings);
836 wake_worker(pool);
837 }
838}
839
840static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
841{
842 unsigned long flags;
843 struct pool *pool = m->tc->pool;
844
845 spin_lock_irqsave(&pool->lock, flags);
846 __complete_mapping_preparation(m);
847 spin_unlock_irqrestore(&pool->lock, flags);
848}
849
850static void copy_complete(int read_err, unsigned long write_err, void *context)
851{
852 struct dm_thin_new_mapping *m = context;
853
854 m->status = read_err || write_err ? BLK_STS_IOERR : 0;
855 complete_mapping_preparation(m);
856}
857
858static void overwrite_endio(struct bio *bio)
859{
860 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
861 struct dm_thin_new_mapping *m = h->overwrite_mapping;
862
863 bio->bi_end_io = m->saved_bi_end_io;
864
865 m->status = bio->bi_status;
866 complete_mapping_preparation(m);
867}
868
869/*----------------------------------------------------------------*/
870
871/*
872 * Workqueue.
873 */
874
875/*
876 * Prepared mapping jobs.
877 */
878
879/*
880 * This sends the bios in the cell, except the original holder, back
881 * to the deferred_bios list.
882 */
883static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
884{
885 struct pool *pool = tc->pool;
886 unsigned long flags;
887 int has_work;
888
889 spin_lock_irqsave(&tc->lock, flags);
890 cell_release_no_holder(pool, cell, &tc->deferred_bio_list);
891 has_work = !bio_list_empty(&tc->deferred_bio_list);
892 spin_unlock_irqrestore(&tc->lock, flags);
893
894 if (has_work)
895 wake_worker(pool);
896}
897
898static void thin_defer_bio(struct thin_c *tc, struct bio *bio);
899
900struct remap_info {
901 struct thin_c *tc;
902 struct bio_list defer_bios;
903 struct bio_list issue_bios;
904};
905
906static void __inc_remap_and_issue_cell(void *context,
907 struct dm_bio_prison_cell *cell)
908{
909 struct remap_info *info = context;
910 struct bio *bio;
911
912 while ((bio = bio_list_pop(&cell->bios))) {
913 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD)
914 bio_list_add(&info->defer_bios, bio);
915 else {
916 inc_all_io_entry(info->tc->pool, bio);
917
918 /*
919 * We can't issue the bios with the bio prison lock
920 * held, so we add them to a list to issue on
921 * return from this function.
922 */
923 bio_list_add(&info->issue_bios, bio);
924 }
925 }
926}
927
928static void inc_remap_and_issue_cell(struct thin_c *tc,
929 struct dm_bio_prison_cell *cell,
930 dm_block_t block)
931{
932 struct bio *bio;
933 struct remap_info info;
934
935 info.tc = tc;
936 bio_list_init(&info.defer_bios);
937 bio_list_init(&info.issue_bios);
938
939 /*
940 * We have to be careful to inc any bios we're about to issue
941 * before the cell is released, and avoid a race with new bios
942 * being added to the cell.
943 */
944 cell_visit_release(tc->pool, __inc_remap_and_issue_cell,
945 &info, cell);
946
947 while ((bio = bio_list_pop(&info.defer_bios)))
948 thin_defer_bio(tc, bio);
949
950 while ((bio = bio_list_pop(&info.issue_bios)))
951 remap_and_issue(info.tc, bio, block);
952}
953
954static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
955{
956 cell_error(m->tc->pool, m->cell);
957 list_del(&m->list);
958 mempool_free(m, &m->tc->pool->mapping_pool);
959}
960
961static void complete_overwrite_bio(struct thin_c *tc, struct bio *bio)
962{
963 struct pool *pool = tc->pool;
964
965 /*
966 * If the bio has the REQ_FUA flag set we must commit the metadata
967 * before signaling its completion.
968 */
969 if (!bio_triggers_commit(tc, bio)) {
970 bio_endio(bio);
971 return;
972 }
973
974 /*
975 * Complete bio with an error if earlier I/O caused changes to the
976 * metadata that can't be committed, e.g, due to I/O errors on the
977 * metadata device.
978 */
979 if (dm_thin_aborted_changes(tc->td)) {
980 bio_io_error(bio);
981 return;
982 }
983
984 /*
985 * Batch together any bios that trigger commits and then issue a
986 * single commit for them in process_deferred_bios().
987 */
988 spin_lock_irq(&pool->lock);
989 bio_list_add(&pool->deferred_flush_completions, bio);
990 spin_unlock_irq(&pool->lock);
991}
992
993static void process_prepared_mapping(struct dm_thin_new_mapping *m)
994{
995 struct thin_c *tc = m->tc;
996 struct pool *pool = tc->pool;
997 struct bio *bio = m->bio;
998 int r;
999
1000 if (m->status) {
1001 cell_error(pool, m->cell);
1002 goto out;
1003 }
1004
1005 /*
1006 * Commit the prepared block into the mapping btree.
1007 * Any I/O for this block arriving after this point will get
1008 * remapped to it directly.
1009 */
1010 r = dm_thin_insert_block(tc->td, m->virt_begin, m->data_block);
1011 if (r) {
1012 metadata_operation_failed(pool, "dm_thin_insert_block", r);
1013 cell_error(pool, m->cell);
1014 goto out;
1015 }
1016
1017 /*
1018 * Release any bios held while the block was being provisioned.
1019 * If we are processing a write bio that completely covers the block,
1020 * we already processed it so can ignore it now when processing
1021 * the bios in the cell.
1022 */
1023 if (bio) {
1024 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
1025 complete_overwrite_bio(tc, bio);
1026 } else {
1027 inc_all_io_entry(tc->pool, m->cell->holder);
1028 remap_and_issue(tc, m->cell->holder, m->data_block);
1029 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
1030 }
1031
1032out:
1033 list_del(&m->list);
1034 mempool_free(m, &pool->mapping_pool);
1035}
1036
1037/*----------------------------------------------------------------*/
1038
1039static void free_discard_mapping(struct dm_thin_new_mapping *m)
1040{
1041 struct thin_c *tc = m->tc;
1042 if (m->cell)
1043 cell_defer_no_holder(tc, m->cell);
1044 mempool_free(m, &tc->pool->mapping_pool);
1045}
1046
1047static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
1048{
1049 bio_io_error(m->bio);
1050 free_discard_mapping(m);
1051}
1052
1053static void process_prepared_discard_success(struct dm_thin_new_mapping *m)
1054{
1055 bio_endio(m->bio);
1056 free_discard_mapping(m);
1057}
1058
1059static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m)
1060{
1061 int r;
1062 struct thin_c *tc = m->tc;
1063
1064 r = dm_thin_remove_range(tc->td, m->cell->key.block_begin, m->cell->key.block_end);
1065 if (r) {
1066 metadata_operation_failed(tc->pool, "dm_thin_remove_range", r);
1067 bio_io_error(m->bio);
1068 } else
1069 bio_endio(m->bio);
1070
1071 cell_defer_no_holder(tc, m->cell);
1072 mempool_free(m, &tc->pool->mapping_pool);
1073}
1074
1075/*----------------------------------------------------------------*/
1076
1077static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m,
1078 struct bio *discard_parent)
1079{
1080 /*
1081 * We've already unmapped this range of blocks, but before we
1082 * passdown we have to check that these blocks are now unused.
1083 */
1084 int r = 0;
1085 bool shared = true;
1086 struct thin_c *tc = m->tc;
1087 struct pool *pool = tc->pool;
1088 dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin;
1089 struct discard_op op;
1090
1091 begin_discard(&op, tc, discard_parent);
1092 while (b != end) {
1093 /* find start of unmapped run */
1094 for (; b < end; b++) {
1095 r = dm_pool_block_is_shared(pool->pmd, b, &shared);
1096 if (r)
1097 goto out;
1098
1099 if (!shared)
1100 break;
1101 }
1102
1103 if (b == end)
1104 break;
1105
1106 /* find end of run */
1107 for (e = b + 1; e != end; e++) {
1108 r = dm_pool_block_is_shared(pool->pmd, e, &shared);
1109 if (r)
1110 goto out;
1111
1112 if (shared)
1113 break;
1114 }
1115
1116 r = issue_discard(&op, b, e);
1117 if (r)
1118 goto out;
1119
1120 b = e;
1121 }
1122out:
1123 end_discard(&op, r);
1124}
1125
1126static void queue_passdown_pt2(struct dm_thin_new_mapping *m)
1127{
1128 unsigned long flags;
1129 struct pool *pool = m->tc->pool;
1130
1131 spin_lock_irqsave(&pool->lock, flags);
1132 list_add_tail(&m->list, &pool->prepared_discards_pt2);
1133 spin_unlock_irqrestore(&pool->lock, flags);
1134 wake_worker(pool);
1135}
1136
1137static void passdown_endio(struct bio *bio)
1138{
1139 /*
1140 * It doesn't matter if the passdown discard failed, we still want
1141 * to unmap (we ignore err).
1142 */
1143 queue_passdown_pt2(bio->bi_private);
1144 bio_put(bio);
1145}
1146
1147static void process_prepared_discard_passdown_pt1(struct dm_thin_new_mapping *m)
1148{
1149 int r;
1150 struct thin_c *tc = m->tc;
1151 struct pool *pool = tc->pool;
1152 struct bio *discard_parent;
1153 dm_block_t data_end = m->data_block + (m->virt_end - m->virt_begin);
1154
1155 /*
1156 * Only this thread allocates blocks, so we can be sure that the
1157 * newly unmapped blocks will not be allocated before the end of
1158 * the function.
1159 */
1160 r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end);
1161 if (r) {
1162 metadata_operation_failed(pool, "dm_thin_remove_range", r);
1163 bio_io_error(m->bio);
1164 cell_defer_no_holder(tc, m->cell);
1165 mempool_free(m, &pool->mapping_pool);
1166 return;
1167 }
1168
1169 /*
1170 * Increment the unmapped blocks. This prevents a race between the
1171 * passdown io and reallocation of freed blocks.
1172 */
1173 r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end);
1174 if (r) {
1175 metadata_operation_failed(pool, "dm_pool_inc_data_range", r);
1176 bio_io_error(m->bio);
1177 cell_defer_no_holder(tc, m->cell);
1178 mempool_free(m, &pool->mapping_pool);
1179 return;
1180 }
1181
1182 discard_parent = bio_alloc(GFP_NOIO, 1);
1183 if (!discard_parent) {
1184 DMWARN("%s: unable to allocate top level discard bio for passdown. Skipping passdown.",
1185 dm_device_name(tc->pool->pool_md));
1186 queue_passdown_pt2(m);
1187
1188 } else {
1189 discard_parent->bi_end_io = passdown_endio;
1190 discard_parent->bi_private = m;
1191
1192 if (m->maybe_shared)
1193 passdown_double_checking_shared_status(m, discard_parent);
1194 else {
1195 struct discard_op op;
1196
1197 begin_discard(&op, tc, discard_parent);
1198 r = issue_discard(&op, m->data_block, data_end);
1199 end_discard(&op, r);
1200 }
1201 }
1202}
1203
1204static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m)
1205{
1206 int r;
1207 struct thin_c *tc = m->tc;
1208 struct pool *pool = tc->pool;
1209
1210 /*
1211 * The passdown has completed, so now we can decrement all those
1212 * unmapped blocks.
1213 */
1214 r = dm_pool_dec_data_range(pool->pmd, m->data_block,
1215 m->data_block + (m->virt_end - m->virt_begin));
1216 if (r) {
1217 metadata_operation_failed(pool, "dm_pool_dec_data_range", r);
1218 bio_io_error(m->bio);
1219 } else
1220 bio_endio(m->bio);
1221
1222 cell_defer_no_holder(tc, m->cell);
1223 mempool_free(m, &pool->mapping_pool);
1224}
1225
1226static void process_prepared(struct pool *pool, struct list_head *head,
1227 process_mapping_fn *fn)
1228{
1229 struct list_head maps;
1230 struct dm_thin_new_mapping *m, *tmp;
1231
1232 INIT_LIST_HEAD(&maps);
1233 spin_lock_irq(&pool->lock);
1234 list_splice_init(head, &maps);
1235 spin_unlock_irq(&pool->lock);
1236
1237 list_for_each_entry_safe(m, tmp, &maps, list)
1238 (*fn)(m);
1239}
1240
1241/*
1242 * Deferred bio jobs.
1243 */
1244static int io_overlaps_block(struct pool *pool, struct bio *bio)
1245{
1246 return bio->bi_iter.bi_size ==
1247 (pool->sectors_per_block << SECTOR_SHIFT);
1248}
1249
1250static int io_overwrites_block(struct pool *pool, struct bio *bio)
1251{
1252 return (bio_data_dir(bio) == WRITE) &&
1253 io_overlaps_block(pool, bio);
1254}
1255
1256static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
1257 bio_end_io_t *fn)
1258{
1259 *save = bio->bi_end_io;
1260 bio->bi_end_io = fn;
1261}
1262
1263static int ensure_next_mapping(struct pool *pool)
1264{
1265 if (pool->next_mapping)
1266 return 0;
1267
1268 pool->next_mapping = mempool_alloc(&pool->mapping_pool, GFP_ATOMIC);
1269
1270 return pool->next_mapping ? 0 : -ENOMEM;
1271}
1272
1273static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
1274{
1275 struct dm_thin_new_mapping *m = pool->next_mapping;
1276
1277 BUG_ON(!pool->next_mapping);
1278
1279 memset(m, 0, sizeof(struct dm_thin_new_mapping));
1280 INIT_LIST_HEAD(&m->list);
1281 m->bio = NULL;
1282
1283 pool->next_mapping = NULL;
1284
1285 return m;
1286}
1287
1288static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
1289 sector_t begin, sector_t end)
1290{
1291 struct dm_io_region to;
1292
1293 to.bdev = tc->pool_dev->bdev;
1294 to.sector = begin;
1295 to.count = end - begin;
1296
1297 dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
1298}
1299
1300static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
1301 dm_block_t data_begin,
1302 struct dm_thin_new_mapping *m)
1303{
1304 struct pool *pool = tc->pool;
1305 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1306
1307 h->overwrite_mapping = m;
1308 m->bio = bio;
1309 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
1310 inc_all_io_entry(pool, bio);
1311 remap_and_issue(tc, bio, data_begin);
1312}
1313
1314/*
1315 * A partial copy also needs to zero the uncopied region.
1316 */
1317static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
1318 struct dm_dev *origin, dm_block_t data_origin,
1319 dm_block_t data_dest,
1320 struct dm_bio_prison_cell *cell, struct bio *bio,
1321 sector_t len)
1322{
1323 struct pool *pool = tc->pool;
1324 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1325
1326 m->tc = tc;
1327 m->virt_begin = virt_block;
1328 m->virt_end = virt_block + 1u;
1329 m->data_block = data_dest;
1330 m->cell = cell;
1331
1332 /*
1333 * quiesce action + copy action + an extra reference held for the
1334 * duration of this function (we may need to inc later for a
1335 * partial zero).
1336 */
1337 atomic_set(&m->prepare_actions, 3);
1338
1339 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
1340 complete_mapping_preparation(m); /* already quiesced */
1341
1342 /*
1343 * IO to pool_dev remaps to the pool target's data_dev.
1344 *
1345 * If the whole block of data is being overwritten, we can issue the
1346 * bio immediately. Otherwise we use kcopyd to clone the data first.
1347 */
1348 if (io_overwrites_block(pool, bio))
1349 remap_and_issue_overwrite(tc, bio, data_dest, m);
1350 else {
1351 struct dm_io_region from, to;
1352
1353 from.bdev = origin->bdev;
1354 from.sector = data_origin * pool->sectors_per_block;
1355 from.count = len;
1356
1357 to.bdev = tc->pool_dev->bdev;
1358 to.sector = data_dest * pool->sectors_per_block;
1359 to.count = len;
1360
1361 dm_kcopyd_copy(pool->copier, &from, 1, &to,
1362 0, copy_complete, m);
1363
1364 /*
1365 * Do we need to zero a tail region?
1366 */
1367 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
1368 atomic_inc(&m->prepare_actions);
1369 ll_zero(tc, m,
1370 data_dest * pool->sectors_per_block + len,
1371 (data_dest + 1) * pool->sectors_per_block);
1372 }
1373 }
1374
1375 complete_mapping_preparation(m); /* drop our ref */
1376}
1377
1378static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
1379 dm_block_t data_origin, dm_block_t data_dest,
1380 struct dm_bio_prison_cell *cell, struct bio *bio)
1381{
1382 schedule_copy(tc, virt_block, tc->pool_dev,
1383 data_origin, data_dest, cell, bio,
1384 tc->pool->sectors_per_block);
1385}
1386
1387static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
1388 dm_block_t data_block, struct dm_bio_prison_cell *cell,
1389 struct bio *bio)
1390{
1391 struct pool *pool = tc->pool;
1392 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1393
1394 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
1395 m->tc = tc;
1396 m->virt_begin = virt_block;
1397 m->virt_end = virt_block + 1u;
1398 m->data_block = data_block;
1399 m->cell = cell;
1400
1401 /*
1402 * If the whole block of data is being overwritten or we are not
1403 * zeroing pre-existing data, we can issue the bio immediately.
1404 * Otherwise we use kcopyd to zero the data first.
1405 */
1406 if (pool->pf.zero_new_blocks) {
1407 if (io_overwrites_block(pool, bio))
1408 remap_and_issue_overwrite(tc, bio, data_block, m);
1409 else
1410 ll_zero(tc, m, data_block * pool->sectors_per_block,
1411 (data_block + 1) * pool->sectors_per_block);
1412 } else
1413 process_prepared_mapping(m);
1414}
1415
1416static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1417 dm_block_t data_dest,
1418 struct dm_bio_prison_cell *cell, struct bio *bio)
1419{
1420 struct pool *pool = tc->pool;
1421 sector_t virt_block_begin = virt_block * pool->sectors_per_block;
1422 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
1423
1424 if (virt_block_end <= tc->origin_size)
1425 schedule_copy(tc, virt_block, tc->origin_dev,
1426 virt_block, data_dest, cell, bio,
1427 pool->sectors_per_block);
1428
1429 else if (virt_block_begin < tc->origin_size)
1430 schedule_copy(tc, virt_block, tc->origin_dev,
1431 virt_block, data_dest, cell, bio,
1432 tc->origin_size - virt_block_begin);
1433
1434 else
1435 schedule_zero(tc, virt_block, data_dest, cell, bio);
1436}
1437
1438static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
1439
1440static void requeue_bios(struct pool *pool);
1441
1442static bool is_read_only_pool_mode(enum pool_mode mode)
1443{
1444 return (mode == PM_OUT_OF_METADATA_SPACE || mode == PM_READ_ONLY);
1445}
1446
1447static bool is_read_only(struct pool *pool)
1448{
1449 return is_read_only_pool_mode(get_pool_mode(pool));
1450}
1451
1452static void check_for_metadata_space(struct pool *pool)
1453{
1454 int r;
1455 const char *ooms_reason = NULL;
1456 dm_block_t nr_free;
1457
1458 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free);
1459 if (r)
1460 ooms_reason = "Could not get free metadata blocks";
1461 else if (!nr_free)
1462 ooms_reason = "No free metadata blocks";
1463
1464 if (ooms_reason && !is_read_only(pool)) {
1465 DMERR("%s", ooms_reason);
1466 set_pool_mode(pool, PM_OUT_OF_METADATA_SPACE);
1467 }
1468}
1469
1470static void check_for_data_space(struct pool *pool)
1471{
1472 int r;
1473 dm_block_t nr_free;
1474
1475 if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)
1476 return;
1477
1478 r = dm_pool_get_free_block_count(pool->pmd, &nr_free);
1479 if (r)
1480 return;
1481
1482 if (nr_free) {
1483 set_pool_mode(pool, PM_WRITE);
1484 requeue_bios(pool);
1485 }
1486}
1487
1488/*
1489 * A non-zero return indicates read_only or fail_io mode.
1490 * Many callers don't care about the return value.
1491 */
1492static int commit(struct pool *pool)
1493{
1494 int r;
1495
1496 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE)
1497 return -EINVAL;
1498
1499 r = dm_pool_commit_metadata(pool->pmd);
1500 if (r)
1501 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
1502 else {
1503 check_for_metadata_space(pool);
1504 check_for_data_space(pool);
1505 }
1506
1507 return r;
1508}
1509
1510static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
1511{
1512 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1513 DMWARN("%s: reached low water mark for data device: sending event.",
1514 dm_device_name(pool->pool_md));
1515 spin_lock_irq(&pool->lock);
1516 pool->low_water_triggered = true;
1517 spin_unlock_irq(&pool->lock);
1518 dm_table_event(pool->ti->table);
1519 }
1520}
1521
1522static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1523{
1524 int r;
1525 dm_block_t free_blocks;
1526 struct pool *pool = tc->pool;
1527
1528 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
1529 return -EINVAL;
1530
1531 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1532 if (r) {
1533 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1534 return r;
1535 }
1536
1537 check_low_water_mark(pool, free_blocks);
1538
1539 if (!free_blocks) {
1540 /*
1541 * Try to commit to see if that will free up some
1542 * more space.
1543 */
1544 r = commit(pool);
1545 if (r)
1546 return r;
1547
1548 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1549 if (r) {
1550 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1551 return r;
1552 }
1553
1554 if (!free_blocks) {
1555 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1556 return -ENOSPC;
1557 }
1558 }
1559
1560 r = dm_pool_alloc_data_block(pool->pmd, result);
1561 if (r) {
1562 if (r == -ENOSPC)
1563 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1564 else
1565 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1566 return r;
1567 }
1568
1569 r = dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks);
1570 if (r) {
1571 metadata_operation_failed(pool, "dm_pool_get_free_metadata_block_count", r);
1572 return r;
1573 }
1574
1575 if (!free_blocks) {
1576 /* Let's commit before we use up the metadata reserve. */
1577 r = commit(pool);
1578 if (r)
1579 return r;
1580 }
1581
1582 return 0;
1583}
1584
1585/*
1586 * If we have run out of space, queue bios until the device is
1587 * resumed, presumably after having been reloaded with more space.
1588 */
1589static void retry_on_resume(struct bio *bio)
1590{
1591 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1592 struct thin_c *tc = h->tc;
1593
1594 spin_lock_irq(&tc->lock);
1595 bio_list_add(&tc->retry_on_resume_list, bio);
1596 spin_unlock_irq(&tc->lock);
1597}
1598
1599static blk_status_t should_error_unserviceable_bio(struct pool *pool)
1600{
1601 enum pool_mode m = get_pool_mode(pool);
1602
1603 switch (m) {
1604 case PM_WRITE:
1605 /* Shouldn't get here */
1606 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1607 return BLK_STS_IOERR;
1608
1609 case PM_OUT_OF_DATA_SPACE:
1610 return pool->pf.error_if_no_space ? BLK_STS_NOSPC : 0;
1611
1612 case PM_OUT_OF_METADATA_SPACE:
1613 case PM_READ_ONLY:
1614 case PM_FAIL:
1615 return BLK_STS_IOERR;
1616 default:
1617 /* Shouldn't get here */
1618 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1619 return BLK_STS_IOERR;
1620 }
1621}
1622
1623static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1624{
1625 blk_status_t error = should_error_unserviceable_bio(pool);
1626
1627 if (error) {
1628 bio->bi_status = error;
1629 bio_endio(bio);
1630 } else
1631 retry_on_resume(bio);
1632}
1633
1634static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1635{
1636 struct bio *bio;
1637 struct bio_list bios;
1638 blk_status_t error;
1639
1640 error = should_error_unserviceable_bio(pool);
1641 if (error) {
1642 cell_error_with_code(pool, cell, error);
1643 return;
1644 }
1645
1646 bio_list_init(&bios);
1647 cell_release(pool, cell, &bios);
1648
1649 while ((bio = bio_list_pop(&bios)))
1650 retry_on_resume(bio);
1651}
1652
1653static void process_discard_cell_no_passdown(struct thin_c *tc,
1654 struct dm_bio_prison_cell *virt_cell)
1655{
1656 struct pool *pool = tc->pool;
1657 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1658
1659 /*
1660 * We don't need to lock the data blocks, since there's no
1661 * passdown. We only lock data blocks for allocation and breaking sharing.
1662 */
1663 m->tc = tc;
1664 m->virt_begin = virt_cell->key.block_begin;
1665 m->virt_end = virt_cell->key.block_end;
1666 m->cell = virt_cell;
1667 m->bio = virt_cell->holder;
1668
1669 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1670 pool->process_prepared_discard(m);
1671}
1672
1673static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end,
1674 struct bio *bio)
1675{
1676 struct pool *pool = tc->pool;
1677
1678 int r;
1679 bool maybe_shared;
1680 struct dm_cell_key data_key;
1681 struct dm_bio_prison_cell *data_cell;
1682 struct dm_thin_new_mapping *m;
1683 dm_block_t virt_begin, virt_end, data_begin;
1684
1685 while (begin != end) {
1686 r = ensure_next_mapping(pool);
1687 if (r)
1688 /* we did our best */
1689 return;
1690
1691 r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end,
1692 &data_begin, &maybe_shared);
1693 if (r)
1694 /*
1695 * Silently fail, letting any mappings we've
1696 * created complete.
1697 */
1698 break;
1699
1700 build_key(tc->td, PHYSICAL, data_begin, data_begin + (virt_end - virt_begin), &data_key);
1701 if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) {
1702 /* contention, we'll give up with this range */
1703 begin = virt_end;
1704 continue;
1705 }
1706
1707 /*
1708 * IO may still be going to the destination block. We must
1709 * quiesce before we can do the removal.
1710 */
1711 m = get_next_mapping(pool);
1712 m->tc = tc;
1713 m->maybe_shared = maybe_shared;
1714 m->virt_begin = virt_begin;
1715 m->virt_end = virt_end;
1716 m->data_block = data_begin;
1717 m->cell = data_cell;
1718 m->bio = bio;
1719
1720 /*
1721 * The parent bio must not complete before sub discard bios are
1722 * chained to it (see end_discard's bio_chain)!
1723 *
1724 * This per-mapping bi_remaining increment is paired with
1725 * the implicit decrement that occurs via bio_endio() in
1726 * end_discard().
1727 */
1728 bio_inc_remaining(bio);
1729 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1730 pool->process_prepared_discard(m);
1731
1732 begin = virt_end;
1733 }
1734}
1735
1736static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell)
1737{
1738 struct bio *bio = virt_cell->holder;
1739 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1740
1741 /*
1742 * The virt_cell will only get freed once the origin bio completes.
1743 * This means it will remain locked while all the individual
1744 * passdown bios are in flight.
1745 */
1746 h->cell = virt_cell;
1747 break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio);
1748
1749 /*
1750 * We complete the bio now, knowing that the bi_remaining field
1751 * will prevent completion until the sub range discards have
1752 * completed.
1753 */
1754 bio_endio(bio);
1755}
1756
1757static void process_discard_bio(struct thin_c *tc, struct bio *bio)
1758{
1759 dm_block_t begin, end;
1760 struct dm_cell_key virt_key;
1761 struct dm_bio_prison_cell *virt_cell;
1762
1763 get_bio_block_range(tc, bio, &begin, &end);
1764 if (begin == end) {
1765 /*
1766 * The discard covers less than a block.
1767 */
1768 bio_endio(bio);
1769 return;
1770 }
1771
1772 build_key(tc->td, VIRTUAL, begin, end, &virt_key);
1773 if (bio_detain(tc->pool, &virt_key, bio, &virt_cell))
1774 /*
1775 * Potential starvation issue: We're relying on the
1776 * fs/application being well behaved, and not trying to
1777 * send IO to a region at the same time as discarding it.
1778 * If they do this persistently then it's possible this
1779 * cell will never be granted.
1780 */
1781 return;
1782
1783 tc->pool->process_discard_cell(tc, virt_cell);
1784}
1785
1786static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1787 struct dm_cell_key *key,
1788 struct dm_thin_lookup_result *lookup_result,
1789 struct dm_bio_prison_cell *cell)
1790{
1791 int r;
1792 dm_block_t data_block;
1793 struct pool *pool = tc->pool;
1794
1795 r = alloc_data_block(tc, &data_block);
1796 switch (r) {
1797 case 0:
1798 schedule_internal_copy(tc, block, lookup_result->block,
1799 data_block, cell, bio);
1800 break;
1801
1802 case -ENOSPC:
1803 retry_bios_on_resume(pool, cell);
1804 break;
1805
1806 default:
1807 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1808 __func__, r);
1809 cell_error(pool, cell);
1810 break;
1811 }
1812}
1813
1814static void __remap_and_issue_shared_cell(void *context,
1815 struct dm_bio_prison_cell *cell)
1816{
1817 struct remap_info *info = context;
1818 struct bio *bio;
1819
1820 while ((bio = bio_list_pop(&cell->bios))) {
1821 if (bio_data_dir(bio) == WRITE || op_is_flush(bio->bi_opf) ||
1822 bio_op(bio) == REQ_OP_DISCARD)
1823 bio_list_add(&info->defer_bios, bio);
1824 else {
1825 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1826
1827 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds);
1828 inc_all_io_entry(info->tc->pool, bio);
1829 bio_list_add(&info->issue_bios, bio);
1830 }
1831 }
1832}
1833
1834static void remap_and_issue_shared_cell(struct thin_c *tc,
1835 struct dm_bio_prison_cell *cell,
1836 dm_block_t block)
1837{
1838 struct bio *bio;
1839 struct remap_info info;
1840
1841 info.tc = tc;
1842 bio_list_init(&info.defer_bios);
1843 bio_list_init(&info.issue_bios);
1844
1845 cell_visit_release(tc->pool, __remap_and_issue_shared_cell,
1846 &info, cell);
1847
1848 while ((bio = bio_list_pop(&info.defer_bios)))
1849 thin_defer_bio(tc, bio);
1850
1851 while ((bio = bio_list_pop(&info.issue_bios)))
1852 remap_and_issue(tc, bio, block);
1853}
1854
1855static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1856 dm_block_t block,
1857 struct dm_thin_lookup_result *lookup_result,
1858 struct dm_bio_prison_cell *virt_cell)
1859{
1860 struct dm_bio_prison_cell *data_cell;
1861 struct pool *pool = tc->pool;
1862 struct dm_cell_key key;
1863
1864 /*
1865 * If cell is already occupied, then sharing is already in the process
1866 * of being broken so we have nothing further to do here.
1867 */
1868 build_data_key(tc->td, lookup_result->block, &key);
1869 if (bio_detain(pool, &key, bio, &data_cell)) {
1870 cell_defer_no_holder(tc, virt_cell);
1871 return;
1872 }
1873
1874 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) {
1875 break_sharing(tc, bio, block, &key, lookup_result, data_cell);
1876 cell_defer_no_holder(tc, virt_cell);
1877 } else {
1878 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1879
1880 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1881 inc_all_io_entry(pool, bio);
1882 remap_and_issue(tc, bio, lookup_result->block);
1883
1884 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block);
1885 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block);
1886 }
1887}
1888
1889static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1890 struct dm_bio_prison_cell *cell)
1891{
1892 int r;
1893 dm_block_t data_block;
1894 struct pool *pool = tc->pool;
1895
1896 /*
1897 * Remap empty bios (flushes) immediately, without provisioning.
1898 */
1899 if (!bio->bi_iter.bi_size) {
1900 inc_all_io_entry(pool, bio);
1901 cell_defer_no_holder(tc, cell);
1902
1903 remap_and_issue(tc, bio, 0);
1904 return;
1905 }
1906
1907 /*
1908 * Fill read bios with zeroes and complete them immediately.
1909 */
1910 if (bio_data_dir(bio) == READ) {
1911 zero_fill_bio(bio);
1912 cell_defer_no_holder(tc, cell);
1913 bio_endio(bio);
1914 return;
1915 }
1916
1917 r = alloc_data_block(tc, &data_block);
1918 switch (r) {
1919 case 0:
1920 if (tc->origin_dev)
1921 schedule_external_copy(tc, block, data_block, cell, bio);
1922 else
1923 schedule_zero(tc, block, data_block, cell, bio);
1924 break;
1925
1926 case -ENOSPC:
1927 retry_bios_on_resume(pool, cell);
1928 break;
1929
1930 default:
1931 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1932 __func__, r);
1933 cell_error(pool, cell);
1934 break;
1935 }
1936}
1937
1938static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1939{
1940 int r;
1941 struct pool *pool = tc->pool;
1942 struct bio *bio = cell->holder;
1943 dm_block_t block = get_bio_block(tc, bio);
1944 struct dm_thin_lookup_result lookup_result;
1945
1946 if (tc->requeue_mode) {
1947 cell_requeue(pool, cell);
1948 return;
1949 }
1950
1951 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1952 switch (r) {
1953 case 0:
1954 if (lookup_result.shared)
1955 process_shared_bio(tc, bio, block, &lookup_result, cell);
1956 else {
1957 inc_all_io_entry(pool, bio);
1958 remap_and_issue(tc, bio, lookup_result.block);
1959 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1960 }
1961 break;
1962
1963 case -ENODATA:
1964 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1965 inc_all_io_entry(pool, bio);
1966 cell_defer_no_holder(tc, cell);
1967
1968 if (bio_end_sector(bio) <= tc->origin_size)
1969 remap_to_origin_and_issue(tc, bio);
1970
1971 else if (bio->bi_iter.bi_sector < tc->origin_size) {
1972 zero_fill_bio(bio);
1973 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
1974 remap_to_origin_and_issue(tc, bio);
1975
1976 } else {
1977 zero_fill_bio(bio);
1978 bio_endio(bio);
1979 }
1980 } else
1981 provision_block(tc, bio, block, cell);
1982 break;
1983
1984 default:
1985 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1986 __func__, r);
1987 cell_defer_no_holder(tc, cell);
1988 bio_io_error(bio);
1989 break;
1990 }
1991}
1992
1993static void process_bio(struct thin_c *tc, struct bio *bio)
1994{
1995 struct pool *pool = tc->pool;
1996 dm_block_t block = get_bio_block(tc, bio);
1997 struct dm_bio_prison_cell *cell;
1998 struct dm_cell_key key;
1999
2000 /*
2001 * If cell is already occupied, then the block is already
2002 * being provisioned so we have nothing further to do here.
2003 */
2004 build_virtual_key(tc->td, block, &key);
2005 if (bio_detain(pool, &key, bio, &cell))
2006 return;
2007
2008 process_cell(tc, cell);
2009}
2010
2011static void __process_bio_read_only(struct thin_c *tc, struct bio *bio,
2012 struct dm_bio_prison_cell *cell)
2013{
2014 int r;
2015 int rw = bio_data_dir(bio);
2016 dm_block_t block = get_bio_block(tc, bio);
2017 struct dm_thin_lookup_result lookup_result;
2018
2019 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
2020 switch (r) {
2021 case 0:
2022 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) {
2023 handle_unserviceable_bio(tc->pool, bio);
2024 if (cell)
2025 cell_defer_no_holder(tc, cell);
2026 } else {
2027 inc_all_io_entry(tc->pool, bio);
2028 remap_and_issue(tc, bio, lookup_result.block);
2029 if (cell)
2030 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
2031 }
2032 break;
2033
2034 case -ENODATA:
2035 if (cell)
2036 cell_defer_no_holder(tc, cell);
2037 if (rw != READ) {
2038 handle_unserviceable_bio(tc->pool, bio);
2039 break;
2040 }
2041
2042 if (tc->origin_dev) {
2043 inc_all_io_entry(tc->pool, bio);
2044 remap_to_origin_and_issue(tc, bio);
2045 break;
2046 }
2047
2048 zero_fill_bio(bio);
2049 bio_endio(bio);
2050 break;
2051
2052 default:
2053 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
2054 __func__, r);
2055 if (cell)
2056 cell_defer_no_holder(tc, cell);
2057 bio_io_error(bio);
2058 break;
2059 }
2060}
2061
2062static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
2063{
2064 __process_bio_read_only(tc, bio, NULL);
2065}
2066
2067static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2068{
2069 __process_bio_read_only(tc, cell->holder, cell);
2070}
2071
2072static void process_bio_success(struct thin_c *tc, struct bio *bio)
2073{
2074 bio_endio(bio);
2075}
2076
2077static void process_bio_fail(struct thin_c *tc, struct bio *bio)
2078{
2079 bio_io_error(bio);
2080}
2081
2082static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2083{
2084 cell_success(tc->pool, cell);
2085}
2086
2087static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2088{
2089 cell_error(tc->pool, cell);
2090}
2091
2092/*
2093 * FIXME: should we also commit due to size of transaction, measured in
2094 * metadata blocks?
2095 */
2096static int need_commit_due_to_time(struct pool *pool)
2097{
2098 return !time_in_range(jiffies, pool->last_commit_jiffies,
2099 pool->last_commit_jiffies + COMMIT_PERIOD);
2100}
2101
2102#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
2103#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
2104
2105static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
2106{
2107 struct rb_node **rbp, *parent;
2108 struct dm_thin_endio_hook *pbd;
2109 sector_t bi_sector = bio->bi_iter.bi_sector;
2110
2111 rbp = &tc->sort_bio_list.rb_node;
2112 parent = NULL;
2113 while (*rbp) {
2114 parent = *rbp;
2115 pbd = thin_pbd(parent);
2116
2117 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
2118 rbp = &(*rbp)->rb_left;
2119 else
2120 rbp = &(*rbp)->rb_right;
2121 }
2122
2123 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2124 rb_link_node(&pbd->rb_node, parent, rbp);
2125 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
2126}
2127
2128static void __extract_sorted_bios(struct thin_c *tc)
2129{
2130 struct rb_node *node;
2131 struct dm_thin_endio_hook *pbd;
2132 struct bio *bio;
2133
2134 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
2135 pbd = thin_pbd(node);
2136 bio = thin_bio(pbd);
2137
2138 bio_list_add(&tc->deferred_bio_list, bio);
2139 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
2140 }
2141
2142 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
2143}
2144
2145static void __sort_thin_deferred_bios(struct thin_c *tc)
2146{
2147 struct bio *bio;
2148 struct bio_list bios;
2149
2150 bio_list_init(&bios);
2151 bio_list_merge(&bios, &tc->deferred_bio_list);
2152 bio_list_init(&tc->deferred_bio_list);
2153
2154 /* Sort deferred_bio_list using rb-tree */
2155 while ((bio = bio_list_pop(&bios)))
2156 __thin_bio_rb_add(tc, bio);
2157
2158 /*
2159 * Transfer the sorted bios in sort_bio_list back to
2160 * deferred_bio_list to allow lockless submission of
2161 * all bios.
2162 */
2163 __extract_sorted_bios(tc);
2164}
2165
2166static void process_thin_deferred_bios(struct thin_c *tc)
2167{
2168 struct pool *pool = tc->pool;
2169 struct bio *bio;
2170 struct bio_list bios;
2171 struct blk_plug plug;
2172 unsigned count = 0;
2173
2174 if (tc->requeue_mode) {
2175 error_thin_bio_list(tc, &tc->deferred_bio_list,
2176 BLK_STS_DM_REQUEUE);
2177 return;
2178 }
2179
2180 bio_list_init(&bios);
2181
2182 spin_lock_irq(&tc->lock);
2183
2184 if (bio_list_empty(&tc->deferred_bio_list)) {
2185 spin_unlock_irq(&tc->lock);
2186 return;
2187 }
2188
2189 __sort_thin_deferred_bios(tc);
2190
2191 bio_list_merge(&bios, &tc->deferred_bio_list);
2192 bio_list_init(&tc->deferred_bio_list);
2193
2194 spin_unlock_irq(&tc->lock);
2195
2196 blk_start_plug(&plug);
2197 while ((bio = bio_list_pop(&bios))) {
2198 /*
2199 * If we've got no free new_mapping structs, and processing
2200 * this bio might require one, we pause until there are some
2201 * prepared mappings to process.
2202 */
2203 if (ensure_next_mapping(pool)) {
2204 spin_lock_irq(&tc->lock);
2205 bio_list_add(&tc->deferred_bio_list, bio);
2206 bio_list_merge(&tc->deferred_bio_list, &bios);
2207 spin_unlock_irq(&tc->lock);
2208 break;
2209 }
2210
2211 if (bio_op(bio) == REQ_OP_DISCARD)
2212 pool->process_discard(tc, bio);
2213 else
2214 pool->process_bio(tc, bio);
2215
2216 if ((count++ & 127) == 0) {
2217 throttle_work_update(&pool->throttle);
2218 dm_pool_issue_prefetches(pool->pmd);
2219 }
2220 }
2221 blk_finish_plug(&plug);
2222}
2223
2224static int cmp_cells(const void *lhs, const void *rhs)
2225{
2226 struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs);
2227 struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs);
2228
2229 BUG_ON(!lhs_cell->holder);
2230 BUG_ON(!rhs_cell->holder);
2231
2232 if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector)
2233 return -1;
2234
2235 if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector)
2236 return 1;
2237
2238 return 0;
2239}
2240
2241static unsigned sort_cells(struct pool *pool, struct list_head *cells)
2242{
2243 unsigned count = 0;
2244 struct dm_bio_prison_cell *cell, *tmp;
2245
2246 list_for_each_entry_safe(cell, tmp, cells, user_list) {
2247 if (count >= CELL_SORT_ARRAY_SIZE)
2248 break;
2249
2250 pool->cell_sort_array[count++] = cell;
2251 list_del(&cell->user_list);
2252 }
2253
2254 sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL);
2255
2256 return count;
2257}
2258
2259static void process_thin_deferred_cells(struct thin_c *tc)
2260{
2261 struct pool *pool = tc->pool;
2262 struct list_head cells;
2263 struct dm_bio_prison_cell *cell;
2264 unsigned i, j, count;
2265
2266 INIT_LIST_HEAD(&cells);
2267
2268 spin_lock_irq(&tc->lock);
2269 list_splice_init(&tc->deferred_cells, &cells);
2270 spin_unlock_irq(&tc->lock);
2271
2272 if (list_empty(&cells))
2273 return;
2274
2275 do {
2276 count = sort_cells(tc->pool, &cells);
2277
2278 for (i = 0; i < count; i++) {
2279 cell = pool->cell_sort_array[i];
2280 BUG_ON(!cell->holder);
2281
2282 /*
2283 * If we've got no free new_mapping structs, and processing
2284 * this bio might require one, we pause until there are some
2285 * prepared mappings to process.
2286 */
2287 if (ensure_next_mapping(pool)) {
2288 for (j = i; j < count; j++)
2289 list_add(&pool->cell_sort_array[j]->user_list, &cells);
2290
2291 spin_lock_irq(&tc->lock);
2292 list_splice(&cells, &tc->deferred_cells);
2293 spin_unlock_irq(&tc->lock);
2294 return;
2295 }
2296
2297 if (bio_op(cell->holder) == REQ_OP_DISCARD)
2298 pool->process_discard_cell(tc, cell);
2299 else
2300 pool->process_cell(tc, cell);
2301 }
2302 } while (!list_empty(&cells));
2303}
2304
2305static void thin_get(struct thin_c *tc);
2306static void thin_put(struct thin_c *tc);
2307
2308/*
2309 * We can't hold rcu_read_lock() around code that can block. So we
2310 * find a thin with the rcu lock held; bump a refcount; then drop
2311 * the lock.
2312 */
2313static struct thin_c *get_first_thin(struct pool *pool)
2314{
2315 struct thin_c *tc = NULL;
2316
2317 rcu_read_lock();
2318 if (!list_empty(&pool->active_thins)) {
2319 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
2320 thin_get(tc);
2321 }
2322 rcu_read_unlock();
2323
2324 return tc;
2325}
2326
2327static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
2328{
2329 struct thin_c *old_tc = tc;
2330
2331 rcu_read_lock();
2332 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
2333 thin_get(tc);
2334 thin_put(old_tc);
2335 rcu_read_unlock();
2336 return tc;
2337 }
2338 thin_put(old_tc);
2339 rcu_read_unlock();
2340
2341 return NULL;
2342}
2343
2344static void process_deferred_bios(struct pool *pool)
2345{
2346 struct bio *bio;
2347 struct bio_list bios, bio_completions;
2348 struct thin_c *tc;
2349
2350 tc = get_first_thin(pool);
2351 while (tc) {
2352 process_thin_deferred_cells(tc);
2353 process_thin_deferred_bios(tc);
2354 tc = get_next_thin(pool, tc);
2355 }
2356
2357 /*
2358 * If there are any deferred flush bios, we must commit the metadata
2359 * before issuing them or signaling their completion.
2360 */
2361 bio_list_init(&bios);
2362 bio_list_init(&bio_completions);
2363
2364 spin_lock_irq(&pool->lock);
2365 bio_list_merge(&bios, &pool->deferred_flush_bios);
2366 bio_list_init(&pool->deferred_flush_bios);
2367
2368 bio_list_merge(&bio_completions, &pool->deferred_flush_completions);
2369 bio_list_init(&pool->deferred_flush_completions);
2370 spin_unlock_irq(&pool->lock);
2371
2372 if (bio_list_empty(&bios) && bio_list_empty(&bio_completions) &&
2373 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
2374 return;
2375
2376 if (commit(pool)) {
2377 bio_list_merge(&bios, &bio_completions);
2378
2379 while ((bio = bio_list_pop(&bios)))
2380 bio_io_error(bio);
2381 return;
2382 }
2383 pool->last_commit_jiffies = jiffies;
2384
2385 while ((bio = bio_list_pop(&bio_completions)))
2386 bio_endio(bio);
2387
2388 while ((bio = bio_list_pop(&bios))) {
2389 /*
2390 * The data device was flushed as part of metadata commit,
2391 * so complete redundant flushes immediately.
2392 */
2393 if (bio->bi_opf & REQ_PREFLUSH)
2394 bio_endio(bio);
2395 else
2396 submit_bio_noacct(bio);
2397 }
2398}
2399
2400static void do_worker(struct work_struct *ws)
2401{
2402 struct pool *pool = container_of(ws, struct pool, worker);
2403
2404 throttle_work_start(&pool->throttle);
2405 dm_pool_issue_prefetches(pool->pmd);
2406 throttle_work_update(&pool->throttle);
2407 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
2408 throttle_work_update(&pool->throttle);
2409 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
2410 throttle_work_update(&pool->throttle);
2411 process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2);
2412 throttle_work_update(&pool->throttle);
2413 process_deferred_bios(pool);
2414 throttle_work_complete(&pool->throttle);
2415}
2416
2417/*
2418 * We want to commit periodically so that not too much
2419 * unwritten data builds up.
2420 */
2421static void do_waker(struct work_struct *ws)
2422{
2423 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
2424 wake_worker(pool);
2425 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
2426}
2427
2428/*
2429 * We're holding onto IO to allow userland time to react. After the
2430 * timeout either the pool will have been resized (and thus back in
2431 * PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space.
2432 */
2433static void do_no_space_timeout(struct work_struct *ws)
2434{
2435 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
2436 no_space_timeout);
2437
2438 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) {
2439 pool->pf.error_if_no_space = true;
2440 notify_of_pool_mode_change(pool);
2441 error_retry_list_with_code(pool, BLK_STS_NOSPC);
2442 }
2443}
2444
2445/*----------------------------------------------------------------*/
2446
2447struct pool_work {
2448 struct work_struct worker;
2449 struct completion complete;
2450};
2451
2452static struct pool_work *to_pool_work(struct work_struct *ws)
2453{
2454 return container_of(ws, struct pool_work, worker);
2455}
2456
2457static void pool_work_complete(struct pool_work *pw)
2458{
2459 complete(&pw->complete);
2460}
2461
2462static void pool_work_wait(struct pool_work *pw, struct pool *pool,
2463 void (*fn)(struct work_struct *))
2464{
2465 INIT_WORK_ONSTACK(&pw->worker, fn);
2466 init_completion(&pw->complete);
2467 queue_work(pool->wq, &pw->worker);
2468 wait_for_completion(&pw->complete);
2469}
2470
2471/*----------------------------------------------------------------*/
2472
2473struct noflush_work {
2474 struct pool_work pw;
2475 struct thin_c *tc;
2476};
2477
2478static struct noflush_work *to_noflush(struct work_struct *ws)
2479{
2480 return container_of(to_pool_work(ws), struct noflush_work, pw);
2481}
2482
2483static void do_noflush_start(struct work_struct *ws)
2484{
2485 struct noflush_work *w = to_noflush(ws);
2486 w->tc->requeue_mode = true;
2487 requeue_io(w->tc);
2488 pool_work_complete(&w->pw);
2489}
2490
2491static void do_noflush_stop(struct work_struct *ws)
2492{
2493 struct noflush_work *w = to_noflush(ws);
2494 w->tc->requeue_mode = false;
2495 pool_work_complete(&w->pw);
2496}
2497
2498static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
2499{
2500 struct noflush_work w;
2501
2502 w.tc = tc;
2503 pool_work_wait(&w.pw, tc->pool, fn);
2504}
2505
2506/*----------------------------------------------------------------*/
2507
2508static bool passdown_enabled(struct pool_c *pt)
2509{
2510 return pt->adjusted_pf.discard_passdown;
2511}
2512
2513static void set_discard_callbacks(struct pool *pool)
2514{
2515 struct pool_c *pt = pool->ti->private;
2516
2517 if (passdown_enabled(pt)) {
2518 pool->process_discard_cell = process_discard_cell_passdown;
2519 pool->process_prepared_discard = process_prepared_discard_passdown_pt1;
2520 pool->process_prepared_discard_pt2 = process_prepared_discard_passdown_pt2;
2521 } else {
2522 pool->process_discard_cell = process_discard_cell_no_passdown;
2523 pool->process_prepared_discard = process_prepared_discard_no_passdown;
2524 }
2525}
2526
2527static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
2528{
2529 struct pool_c *pt = pool->ti->private;
2530 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
2531 enum pool_mode old_mode = get_pool_mode(pool);
2532 unsigned long no_space_timeout = READ_ONCE(no_space_timeout_secs) * HZ;
2533
2534 /*
2535 * Never allow the pool to transition to PM_WRITE mode if user
2536 * intervention is required to verify metadata and data consistency.
2537 */
2538 if (new_mode == PM_WRITE && needs_check) {
2539 DMERR("%s: unable to switch pool to write mode until repaired.",
2540 dm_device_name(pool->pool_md));
2541 if (old_mode != new_mode)
2542 new_mode = old_mode;
2543 else
2544 new_mode = PM_READ_ONLY;
2545 }
2546 /*
2547 * If we were in PM_FAIL mode, rollback of metadata failed. We're
2548 * not going to recover without a thin_repair. So we never let the
2549 * pool move out of the old mode.
2550 */
2551 if (old_mode == PM_FAIL)
2552 new_mode = old_mode;
2553
2554 switch (new_mode) {
2555 case PM_FAIL:
2556 dm_pool_metadata_read_only(pool->pmd);
2557 pool->process_bio = process_bio_fail;
2558 pool->process_discard = process_bio_fail;
2559 pool->process_cell = process_cell_fail;
2560 pool->process_discard_cell = process_cell_fail;
2561 pool->process_prepared_mapping = process_prepared_mapping_fail;
2562 pool->process_prepared_discard = process_prepared_discard_fail;
2563
2564 error_retry_list(pool);
2565 break;
2566
2567 case PM_OUT_OF_METADATA_SPACE:
2568 case PM_READ_ONLY:
2569 dm_pool_metadata_read_only(pool->pmd);
2570 pool->process_bio = process_bio_read_only;
2571 pool->process_discard = process_bio_success;
2572 pool->process_cell = process_cell_read_only;
2573 pool->process_discard_cell = process_cell_success;
2574 pool->process_prepared_mapping = process_prepared_mapping_fail;
2575 pool->process_prepared_discard = process_prepared_discard_success;
2576
2577 error_retry_list(pool);
2578 break;
2579
2580 case PM_OUT_OF_DATA_SPACE:
2581 /*
2582 * Ideally we'd never hit this state; the low water mark
2583 * would trigger userland to extend the pool before we
2584 * completely run out of data space. However, many small
2585 * IOs to unprovisioned space can consume data space at an
2586 * alarming rate. Adjust your low water mark if you're
2587 * frequently seeing this mode.
2588 */
2589 pool->out_of_data_space = true;
2590 pool->process_bio = process_bio_read_only;
2591 pool->process_discard = process_discard_bio;
2592 pool->process_cell = process_cell_read_only;
2593 pool->process_prepared_mapping = process_prepared_mapping;
2594 set_discard_callbacks(pool);
2595
2596 if (!pool->pf.error_if_no_space && no_space_timeout)
2597 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
2598 break;
2599
2600 case PM_WRITE:
2601 if (old_mode == PM_OUT_OF_DATA_SPACE)
2602 cancel_delayed_work_sync(&pool->no_space_timeout);
2603 pool->out_of_data_space = false;
2604 pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space;
2605 dm_pool_metadata_read_write(pool->pmd);
2606 pool->process_bio = process_bio;
2607 pool->process_discard = process_discard_bio;
2608 pool->process_cell = process_cell;
2609 pool->process_prepared_mapping = process_prepared_mapping;
2610 set_discard_callbacks(pool);
2611 break;
2612 }
2613
2614 pool->pf.mode = new_mode;
2615 /*
2616 * The pool mode may have changed, sync it so bind_control_target()
2617 * doesn't cause an unexpected mode transition on resume.
2618 */
2619 pt->adjusted_pf.mode = new_mode;
2620
2621 if (old_mode != new_mode)
2622 notify_of_pool_mode_change(pool);
2623}
2624
2625static void abort_transaction(struct pool *pool)
2626{
2627 const char *dev_name = dm_device_name(pool->pool_md);
2628
2629 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
2630 if (dm_pool_abort_metadata(pool->pmd)) {
2631 DMERR("%s: failed to abort metadata transaction", dev_name);
2632 set_pool_mode(pool, PM_FAIL);
2633 }
2634
2635 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
2636 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
2637 set_pool_mode(pool, PM_FAIL);
2638 }
2639}
2640
2641static void metadata_operation_failed(struct pool *pool, const char *op, int r)
2642{
2643 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
2644 dm_device_name(pool->pool_md), op, r);
2645
2646 abort_transaction(pool);
2647 set_pool_mode(pool, PM_READ_ONLY);
2648}
2649
2650/*----------------------------------------------------------------*/
2651
2652/*
2653 * Mapping functions.
2654 */
2655
2656/*
2657 * Called only while mapping a thin bio to hand it over to the workqueue.
2658 */
2659static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
2660{
2661 struct pool *pool = tc->pool;
2662
2663 spin_lock_irq(&tc->lock);
2664 bio_list_add(&tc->deferred_bio_list, bio);
2665 spin_unlock_irq(&tc->lock);
2666
2667 wake_worker(pool);
2668}
2669
2670static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
2671{
2672 struct pool *pool = tc->pool;
2673
2674 throttle_lock(&pool->throttle);
2675 thin_defer_bio(tc, bio);
2676 throttle_unlock(&pool->throttle);
2677}
2678
2679static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2680{
2681 struct pool *pool = tc->pool;
2682
2683 throttle_lock(&pool->throttle);
2684 spin_lock_irq(&tc->lock);
2685 list_add_tail(&cell->user_list, &tc->deferred_cells);
2686 spin_unlock_irq(&tc->lock);
2687 throttle_unlock(&pool->throttle);
2688
2689 wake_worker(pool);
2690}
2691
2692static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
2693{
2694 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2695
2696 h->tc = tc;
2697 h->shared_read_entry = NULL;
2698 h->all_io_entry = NULL;
2699 h->overwrite_mapping = NULL;
2700 h->cell = NULL;
2701}
2702
2703/*
2704 * Non-blocking function called from the thin target's map function.
2705 */
2706static int thin_bio_map(struct dm_target *ti, struct bio *bio)
2707{
2708 int r;
2709 struct thin_c *tc = ti->private;
2710 dm_block_t block = get_bio_block(tc, bio);
2711 struct dm_thin_device *td = tc->td;
2712 struct dm_thin_lookup_result result;
2713 struct dm_bio_prison_cell *virt_cell, *data_cell;
2714 struct dm_cell_key key;
2715
2716 thin_hook_bio(tc, bio);
2717
2718 if (tc->requeue_mode) {
2719 bio->bi_status = BLK_STS_DM_REQUEUE;
2720 bio_endio(bio);
2721 return DM_MAPIO_SUBMITTED;
2722 }
2723
2724 if (get_pool_mode(tc->pool) == PM_FAIL) {
2725 bio_io_error(bio);
2726 return DM_MAPIO_SUBMITTED;
2727 }
2728
2729 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) {
2730 thin_defer_bio_with_throttle(tc, bio);
2731 return DM_MAPIO_SUBMITTED;
2732 }
2733
2734 /*
2735 * We must hold the virtual cell before doing the lookup, otherwise
2736 * there's a race with discard.
2737 */
2738 build_virtual_key(tc->td, block, &key);
2739 if (bio_detain(tc->pool, &key, bio, &virt_cell))
2740 return DM_MAPIO_SUBMITTED;
2741
2742 r = dm_thin_find_block(td, block, 0, &result);
2743
2744 /*
2745 * Note that we defer readahead too.
2746 */
2747 switch (r) {
2748 case 0:
2749 if (unlikely(result.shared)) {
2750 /*
2751 * We have a race condition here between the
2752 * result.shared value returned by the lookup and
2753 * snapshot creation, which may cause new
2754 * sharing.
2755 *
2756 * To avoid this always quiesce the origin before
2757 * taking the snap. You want to do this anyway to
2758 * ensure a consistent application view
2759 * (i.e. lockfs).
2760 *
2761 * More distant ancestors are irrelevant. The
2762 * shared flag will be set in their case.
2763 */
2764 thin_defer_cell(tc, virt_cell);
2765 return DM_MAPIO_SUBMITTED;
2766 }
2767
2768 build_data_key(tc->td, result.block, &key);
2769 if (bio_detain(tc->pool, &key, bio, &data_cell)) {
2770 cell_defer_no_holder(tc, virt_cell);
2771 return DM_MAPIO_SUBMITTED;
2772 }
2773
2774 inc_all_io_entry(tc->pool, bio);
2775 cell_defer_no_holder(tc, data_cell);
2776 cell_defer_no_holder(tc, virt_cell);
2777
2778 remap(tc, bio, result.block);
2779 return DM_MAPIO_REMAPPED;
2780
2781 case -ENODATA:
2782 case -EWOULDBLOCK:
2783 thin_defer_cell(tc, virt_cell);
2784 return DM_MAPIO_SUBMITTED;
2785
2786 default:
2787 /*
2788 * Must always call bio_io_error on failure.
2789 * dm_thin_find_block can fail with -EINVAL if the
2790 * pool is switched to fail-io mode.
2791 */
2792 bio_io_error(bio);
2793 cell_defer_no_holder(tc, virt_cell);
2794 return DM_MAPIO_SUBMITTED;
2795 }
2796}
2797
2798static void requeue_bios(struct pool *pool)
2799{
2800 struct thin_c *tc;
2801
2802 rcu_read_lock();
2803 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
2804 spin_lock_irq(&tc->lock);
2805 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
2806 bio_list_init(&tc->retry_on_resume_list);
2807 spin_unlock_irq(&tc->lock);
2808 }
2809 rcu_read_unlock();
2810}
2811
2812/*----------------------------------------------------------------
2813 * Binding of control targets to a pool object
2814 *--------------------------------------------------------------*/
2815static bool data_dev_supports_discard(struct pool_c *pt)
2816{
2817 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2818
2819 return blk_queue_discard(q);
2820}
2821
2822static bool is_factor(sector_t block_size, uint32_t n)
2823{
2824 return !sector_div(block_size, n);
2825}
2826
2827/*
2828 * If discard_passdown was enabled verify that the data device
2829 * supports discards. Disable discard_passdown if not.
2830 */
2831static void disable_passdown_if_not_supported(struct pool_c *pt)
2832{
2833 struct pool *pool = pt->pool;
2834 struct block_device *data_bdev = pt->data_dev->bdev;
2835 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
2836 const char *reason = NULL;
2837 char buf[BDEVNAME_SIZE];
2838
2839 if (!pt->adjusted_pf.discard_passdown)
2840 return;
2841
2842 if (!data_dev_supports_discard(pt))
2843 reason = "discard unsupported";
2844
2845 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
2846 reason = "max discard sectors smaller than a block";
2847
2848 if (reason) {
2849 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
2850 pt->adjusted_pf.discard_passdown = false;
2851 }
2852}
2853
2854static int bind_control_target(struct pool *pool, struct dm_target *ti)
2855{
2856 struct pool_c *pt = ti->private;
2857
2858 /*
2859 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2860 */
2861 enum pool_mode old_mode = get_pool_mode(pool);
2862 enum pool_mode new_mode = pt->adjusted_pf.mode;
2863
2864 /*
2865 * Don't change the pool's mode until set_pool_mode() below.
2866 * Otherwise the pool's process_* function pointers may
2867 * not match the desired pool mode.
2868 */
2869 pt->adjusted_pf.mode = old_mode;
2870
2871 pool->ti = ti;
2872 pool->pf = pt->adjusted_pf;
2873 pool->low_water_blocks = pt->low_water_blocks;
2874
2875 set_pool_mode(pool, new_mode);
2876
2877 return 0;
2878}
2879
2880static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2881{
2882 if (pool->ti == ti)
2883 pool->ti = NULL;
2884}
2885
2886/*----------------------------------------------------------------
2887 * Pool creation
2888 *--------------------------------------------------------------*/
2889/* Initialize pool features. */
2890static void pool_features_init(struct pool_features *pf)
2891{
2892 pf->mode = PM_WRITE;
2893 pf->zero_new_blocks = true;
2894 pf->discard_enabled = true;
2895 pf->discard_passdown = true;
2896 pf->error_if_no_space = false;
2897}
2898
2899static void __pool_destroy(struct pool *pool)
2900{
2901 __pool_table_remove(pool);
2902
2903 vfree(pool->cell_sort_array);
2904 if (dm_pool_metadata_close(pool->pmd) < 0)
2905 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2906
2907 dm_bio_prison_destroy(pool->prison);
2908 dm_kcopyd_client_destroy(pool->copier);
2909
2910 if (pool->wq)
2911 destroy_workqueue(pool->wq);
2912
2913 if (pool->next_mapping)
2914 mempool_free(pool->next_mapping, &pool->mapping_pool);
2915 mempool_exit(&pool->mapping_pool);
2916 bio_uninit(&pool->flush_bio);
2917 dm_deferred_set_destroy(pool->shared_read_ds);
2918 dm_deferred_set_destroy(pool->all_io_ds);
2919 kfree(pool);
2920}
2921
2922static struct kmem_cache *_new_mapping_cache;
2923
2924static struct pool *pool_create(struct mapped_device *pool_md,
2925 struct block_device *metadata_dev,
2926 struct block_device *data_dev,
2927 unsigned long block_size,
2928 int read_only, char **error)
2929{
2930 int r;
2931 void *err_p;
2932 struct pool *pool;
2933 struct dm_pool_metadata *pmd;
2934 bool format_device = read_only ? false : true;
2935
2936 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2937 if (IS_ERR(pmd)) {
2938 *error = "Error creating metadata object";
2939 return (struct pool *)pmd;
2940 }
2941
2942 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
2943 if (!pool) {
2944 *error = "Error allocating memory for pool";
2945 err_p = ERR_PTR(-ENOMEM);
2946 goto bad_pool;
2947 }
2948
2949 pool->pmd = pmd;
2950 pool->sectors_per_block = block_size;
2951 if (block_size & (block_size - 1))
2952 pool->sectors_per_block_shift = -1;
2953 else
2954 pool->sectors_per_block_shift = __ffs(block_size);
2955 pool->low_water_blocks = 0;
2956 pool_features_init(&pool->pf);
2957 pool->prison = dm_bio_prison_create();
2958 if (!pool->prison) {
2959 *error = "Error creating pool's bio prison";
2960 err_p = ERR_PTR(-ENOMEM);
2961 goto bad_prison;
2962 }
2963
2964 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2965 if (IS_ERR(pool->copier)) {
2966 r = PTR_ERR(pool->copier);
2967 *error = "Error creating pool's kcopyd client";
2968 err_p = ERR_PTR(r);
2969 goto bad_kcopyd_client;
2970 }
2971
2972 /*
2973 * Create singlethreaded workqueue that will service all devices
2974 * that use this metadata.
2975 */
2976 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2977 if (!pool->wq) {
2978 *error = "Error creating pool's workqueue";
2979 err_p = ERR_PTR(-ENOMEM);
2980 goto bad_wq;
2981 }
2982
2983 throttle_init(&pool->throttle);
2984 INIT_WORK(&pool->worker, do_worker);
2985 INIT_DELAYED_WORK(&pool->waker, do_waker);
2986 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
2987 spin_lock_init(&pool->lock);
2988 bio_list_init(&pool->deferred_flush_bios);
2989 bio_list_init(&pool->deferred_flush_completions);
2990 INIT_LIST_HEAD(&pool->prepared_mappings);
2991 INIT_LIST_HEAD(&pool->prepared_discards);
2992 INIT_LIST_HEAD(&pool->prepared_discards_pt2);
2993 INIT_LIST_HEAD(&pool->active_thins);
2994 pool->low_water_triggered = false;
2995 pool->suspended = true;
2996 pool->out_of_data_space = false;
2997 bio_init(&pool->flush_bio, NULL, 0);
2998
2999 pool->shared_read_ds = dm_deferred_set_create();
3000 if (!pool->shared_read_ds) {
3001 *error = "Error creating pool's shared read deferred set";
3002 err_p = ERR_PTR(-ENOMEM);
3003 goto bad_shared_read_ds;
3004 }
3005
3006 pool->all_io_ds = dm_deferred_set_create();
3007 if (!pool->all_io_ds) {
3008 *error = "Error creating pool's all io deferred set";
3009 err_p = ERR_PTR(-ENOMEM);
3010 goto bad_all_io_ds;
3011 }
3012
3013 pool->next_mapping = NULL;
3014 r = mempool_init_slab_pool(&pool->mapping_pool, MAPPING_POOL_SIZE,
3015 _new_mapping_cache);
3016 if (r) {
3017 *error = "Error creating pool's mapping mempool";
3018 err_p = ERR_PTR(r);
3019 goto bad_mapping_pool;
3020 }
3021
3022 pool->cell_sort_array =
3023 vmalloc(array_size(CELL_SORT_ARRAY_SIZE,
3024 sizeof(*pool->cell_sort_array)));
3025 if (!pool->cell_sort_array) {
3026 *error = "Error allocating cell sort array";
3027 err_p = ERR_PTR(-ENOMEM);
3028 goto bad_sort_array;
3029 }
3030
3031 pool->ref_count = 1;
3032 pool->last_commit_jiffies = jiffies;
3033 pool->pool_md = pool_md;
3034 pool->md_dev = metadata_dev;
3035 pool->data_dev = data_dev;
3036 __pool_table_insert(pool);
3037
3038 return pool;
3039
3040bad_sort_array:
3041 mempool_exit(&pool->mapping_pool);
3042bad_mapping_pool:
3043 dm_deferred_set_destroy(pool->all_io_ds);
3044bad_all_io_ds:
3045 dm_deferred_set_destroy(pool->shared_read_ds);
3046bad_shared_read_ds:
3047 destroy_workqueue(pool->wq);
3048bad_wq:
3049 dm_kcopyd_client_destroy(pool->copier);
3050bad_kcopyd_client:
3051 dm_bio_prison_destroy(pool->prison);
3052bad_prison:
3053 kfree(pool);
3054bad_pool:
3055 if (dm_pool_metadata_close(pmd))
3056 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
3057
3058 return err_p;
3059}
3060
3061static void __pool_inc(struct pool *pool)
3062{
3063 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
3064 pool->ref_count++;
3065}
3066
3067static void __pool_dec(struct pool *pool)
3068{
3069 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
3070 BUG_ON(!pool->ref_count);
3071 if (!--pool->ref_count)
3072 __pool_destroy(pool);
3073}
3074
3075static struct pool *__pool_find(struct mapped_device *pool_md,
3076 struct block_device *metadata_dev,
3077 struct block_device *data_dev,
3078 unsigned long block_size, int read_only,
3079 char **error, int *created)
3080{
3081 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
3082
3083 if (pool) {
3084 if (pool->pool_md != pool_md) {
3085 *error = "metadata device already in use by a pool";
3086 return ERR_PTR(-EBUSY);
3087 }
3088 if (pool->data_dev != data_dev) {
3089 *error = "data device already in use by a pool";
3090 return ERR_PTR(-EBUSY);
3091 }
3092 __pool_inc(pool);
3093
3094 } else {
3095 pool = __pool_table_lookup(pool_md);
3096 if (pool) {
3097 if (pool->md_dev != metadata_dev || pool->data_dev != data_dev) {
3098 *error = "different pool cannot replace a pool";
3099 return ERR_PTR(-EINVAL);
3100 }
3101 __pool_inc(pool);
3102
3103 } else {
3104 pool = pool_create(pool_md, metadata_dev, data_dev, block_size, read_only, error);
3105 *created = 1;
3106 }
3107 }
3108
3109 return pool;
3110}
3111
3112/*----------------------------------------------------------------
3113 * Pool target methods
3114 *--------------------------------------------------------------*/
3115static void pool_dtr(struct dm_target *ti)
3116{
3117 struct pool_c *pt = ti->private;
3118
3119 mutex_lock(&dm_thin_pool_table.mutex);
3120
3121 unbind_control_target(pt->pool, ti);
3122 __pool_dec(pt->pool);
3123 dm_put_device(ti, pt->metadata_dev);
3124 dm_put_device(ti, pt->data_dev);
3125 kfree(pt);
3126
3127 mutex_unlock(&dm_thin_pool_table.mutex);
3128}
3129
3130static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
3131 struct dm_target *ti)
3132{
3133 int r;
3134 unsigned argc;
3135 const char *arg_name;
3136
3137 static const struct dm_arg _args[] = {
3138 {0, 4, "Invalid number of pool feature arguments"},
3139 };
3140
3141 /*
3142 * No feature arguments supplied.
3143 */
3144 if (!as->argc)
3145 return 0;
3146
3147 r = dm_read_arg_group(_args, as, &argc, &ti->error);
3148 if (r)
3149 return -EINVAL;
3150
3151 while (argc && !r) {
3152 arg_name = dm_shift_arg(as);
3153 argc--;
3154
3155 if (!strcasecmp(arg_name, "skip_block_zeroing"))
3156 pf->zero_new_blocks = false;
3157
3158 else if (!strcasecmp(arg_name, "ignore_discard"))
3159 pf->discard_enabled = false;
3160
3161 else if (!strcasecmp(arg_name, "no_discard_passdown"))
3162 pf->discard_passdown = false;
3163
3164 else if (!strcasecmp(arg_name, "read_only"))
3165 pf->mode = PM_READ_ONLY;
3166
3167 else if (!strcasecmp(arg_name, "error_if_no_space"))
3168 pf->error_if_no_space = true;
3169
3170 else {
3171 ti->error = "Unrecognised pool feature requested";
3172 r = -EINVAL;
3173 break;
3174 }
3175 }
3176
3177 return r;
3178}
3179
3180static void metadata_low_callback(void *context)
3181{
3182 struct pool *pool = context;
3183
3184 DMWARN("%s: reached low water mark for metadata device: sending event.",
3185 dm_device_name(pool->pool_md));
3186
3187 dm_table_event(pool->ti->table);
3188}
3189
3190/*
3191 * We need to flush the data device **before** committing the metadata.
3192 *
3193 * This ensures that the data blocks of any newly inserted mappings are
3194 * properly written to non-volatile storage and won't be lost in case of a
3195 * crash.
3196 *
3197 * Failure to do so can result in data corruption in the case of internal or
3198 * external snapshots and in the case of newly provisioned blocks, when block
3199 * zeroing is enabled.
3200 */
3201static int metadata_pre_commit_callback(void *context)
3202{
3203 struct pool *pool = context;
3204 struct bio *flush_bio = &pool->flush_bio;
3205
3206 bio_reset(flush_bio);
3207 bio_set_dev(flush_bio, pool->data_dev);
3208 flush_bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
3209
3210 return submit_bio_wait(flush_bio);
3211}
3212
3213static sector_t get_dev_size(struct block_device *bdev)
3214{
3215 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
3216}
3217
3218static void warn_if_metadata_device_too_big(struct block_device *bdev)
3219{
3220 sector_t metadata_dev_size = get_dev_size(bdev);
3221 char buffer[BDEVNAME_SIZE];
3222
3223 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
3224 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
3225 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
3226}
3227
3228static sector_t get_metadata_dev_size(struct block_device *bdev)
3229{
3230 sector_t metadata_dev_size = get_dev_size(bdev);
3231
3232 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
3233 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
3234
3235 return metadata_dev_size;
3236}
3237
3238static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
3239{
3240 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
3241
3242 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
3243
3244 return metadata_dev_size;
3245}
3246
3247/*
3248 * When a metadata threshold is crossed a dm event is triggered, and
3249 * userland should respond by growing the metadata device. We could let
3250 * userland set the threshold, like we do with the data threshold, but I'm
3251 * not sure they know enough to do this well.
3252 */
3253static dm_block_t calc_metadata_threshold(struct pool_c *pt)
3254{
3255 /*
3256 * 4M is ample for all ops with the possible exception of thin
3257 * device deletion which is harmless if it fails (just retry the
3258 * delete after you've grown the device).
3259 */
3260 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
3261 return min((dm_block_t)1024ULL /* 4M */, quarter);
3262}
3263
3264/*
3265 * thin-pool <metadata dev> <data dev>
3266 * <data block size (sectors)>
3267 * <low water mark (blocks)>
3268 * [<#feature args> [<arg>]*]
3269 *
3270 * Optional feature arguments are:
3271 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
3272 * ignore_discard: disable discard
3273 * no_discard_passdown: don't pass discards down to the data device
3274 * read_only: Don't allow any changes to be made to the pool metadata.
3275 * error_if_no_space: error IOs, instead of queueing, if no space.
3276 */
3277static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
3278{
3279 int r, pool_created = 0;
3280 struct pool_c *pt;
3281 struct pool *pool;
3282 struct pool_features pf;
3283 struct dm_arg_set as;
3284 struct dm_dev *data_dev;
3285 unsigned long block_size;
3286 dm_block_t low_water_blocks;
3287 struct dm_dev *metadata_dev;
3288 fmode_t metadata_mode;
3289
3290 /*
3291 * FIXME Remove validation from scope of lock.
3292 */
3293 mutex_lock(&dm_thin_pool_table.mutex);
3294
3295 if (argc < 4) {
3296 ti->error = "Invalid argument count";
3297 r = -EINVAL;
3298 goto out_unlock;
3299 }
3300
3301 as.argc = argc;
3302 as.argv = argv;
3303
3304 /* make sure metadata and data are different devices */
3305 if (!strcmp(argv[0], argv[1])) {
3306 ti->error = "Error setting metadata or data device";
3307 r = -EINVAL;
3308 goto out_unlock;
3309 }
3310
3311 /*
3312 * Set default pool features.
3313 */
3314 pool_features_init(&pf);
3315
3316 dm_consume_args(&as, 4);
3317 r = parse_pool_features(&as, &pf, ti);
3318 if (r)
3319 goto out_unlock;
3320
3321 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
3322 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
3323 if (r) {
3324 ti->error = "Error opening metadata block device";
3325 goto out_unlock;
3326 }
3327 warn_if_metadata_device_too_big(metadata_dev->bdev);
3328
3329 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
3330 if (r) {
3331 ti->error = "Error getting data device";
3332 goto out_metadata;
3333 }
3334
3335 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
3336 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
3337 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
3338 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
3339 ti->error = "Invalid block size";
3340 r = -EINVAL;
3341 goto out;
3342 }
3343
3344 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
3345 ti->error = "Invalid low water mark";
3346 r = -EINVAL;
3347 goto out;
3348 }
3349
3350 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
3351 if (!pt) {
3352 r = -ENOMEM;
3353 goto out;
3354 }
3355
3356 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, data_dev->bdev,
3357 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
3358 if (IS_ERR(pool)) {
3359 r = PTR_ERR(pool);
3360 goto out_free_pt;
3361 }
3362
3363 /*
3364 * 'pool_created' reflects whether this is the first table load.
3365 * Top level discard support is not allowed to be changed after
3366 * initial load. This would require a pool reload to trigger thin
3367 * device changes.
3368 */
3369 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
3370 ti->error = "Discard support cannot be disabled once enabled";
3371 r = -EINVAL;
3372 goto out_flags_changed;
3373 }
3374
3375 pt->pool = pool;
3376 pt->ti = ti;
3377 pt->metadata_dev = metadata_dev;
3378 pt->data_dev = data_dev;
3379 pt->low_water_blocks = low_water_blocks;
3380 pt->adjusted_pf = pt->requested_pf = pf;
3381 ti->num_flush_bios = 1;
3382
3383 /*
3384 * Only need to enable discards if the pool should pass
3385 * them down to the data device. The thin device's discard
3386 * processing will cause mappings to be removed from the btree.
3387 */
3388 if (pf.discard_enabled && pf.discard_passdown) {
3389 ti->num_discard_bios = 1;
3390
3391 /*
3392 * Setting 'discards_supported' circumvents the normal
3393 * stacking of discard limits (this keeps the pool and
3394 * thin devices' discard limits consistent).
3395 */
3396 ti->discards_supported = true;
3397 }
3398 ti->private = pt;
3399
3400 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
3401 calc_metadata_threshold(pt),
3402 metadata_low_callback,
3403 pool);
3404 if (r)
3405 goto out_flags_changed;
3406
3407 dm_pool_register_pre_commit_callback(pool->pmd,
3408 metadata_pre_commit_callback, pool);
3409
3410 mutex_unlock(&dm_thin_pool_table.mutex);
3411
3412 return 0;
3413
3414out_flags_changed:
3415 __pool_dec(pool);
3416out_free_pt:
3417 kfree(pt);
3418out:
3419 dm_put_device(ti, data_dev);
3420out_metadata:
3421 dm_put_device(ti, metadata_dev);
3422out_unlock:
3423 mutex_unlock(&dm_thin_pool_table.mutex);
3424
3425 return r;
3426}
3427
3428static int pool_map(struct dm_target *ti, struct bio *bio)
3429{
3430 int r;
3431 struct pool_c *pt = ti->private;
3432 struct pool *pool = pt->pool;
3433
3434 /*
3435 * As this is a singleton target, ti->begin is always zero.
3436 */
3437 spin_lock_irq(&pool->lock);
3438 bio_set_dev(bio, pt->data_dev->bdev);
3439 r = DM_MAPIO_REMAPPED;
3440 spin_unlock_irq(&pool->lock);
3441
3442 return r;
3443}
3444
3445static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
3446{
3447 int r;
3448 struct pool_c *pt = ti->private;
3449 struct pool *pool = pt->pool;
3450 sector_t data_size = ti->len;
3451 dm_block_t sb_data_size;
3452
3453 *need_commit = false;
3454
3455 (void) sector_div(data_size, pool->sectors_per_block);
3456
3457 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
3458 if (r) {
3459 DMERR("%s: failed to retrieve data device size",
3460 dm_device_name(pool->pool_md));
3461 return r;
3462 }
3463
3464 if (data_size < sb_data_size) {
3465 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
3466 dm_device_name(pool->pool_md),
3467 (unsigned long long)data_size, sb_data_size);
3468 return -EINVAL;
3469
3470 } else if (data_size > sb_data_size) {
3471 if (dm_pool_metadata_needs_check(pool->pmd)) {
3472 DMERR("%s: unable to grow the data device until repaired.",
3473 dm_device_name(pool->pool_md));
3474 return 0;
3475 }
3476
3477 if (sb_data_size)
3478 DMINFO("%s: growing the data device from %llu to %llu blocks",
3479 dm_device_name(pool->pool_md),
3480 sb_data_size, (unsigned long long)data_size);
3481 r = dm_pool_resize_data_dev(pool->pmd, data_size);
3482 if (r) {
3483 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
3484 return r;
3485 }
3486
3487 *need_commit = true;
3488 }
3489
3490 return 0;
3491}
3492
3493static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
3494{
3495 int r;
3496 struct pool_c *pt = ti->private;
3497 struct pool *pool = pt->pool;
3498 dm_block_t metadata_dev_size, sb_metadata_dev_size;
3499
3500 *need_commit = false;
3501
3502 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
3503
3504 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
3505 if (r) {
3506 DMERR("%s: failed to retrieve metadata device size",
3507 dm_device_name(pool->pool_md));
3508 return r;
3509 }
3510
3511 if (metadata_dev_size < sb_metadata_dev_size) {
3512 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
3513 dm_device_name(pool->pool_md),
3514 metadata_dev_size, sb_metadata_dev_size);
3515 return -EINVAL;
3516
3517 } else if (metadata_dev_size > sb_metadata_dev_size) {
3518 if (dm_pool_metadata_needs_check(pool->pmd)) {
3519 DMERR("%s: unable to grow the metadata device until repaired.",
3520 dm_device_name(pool->pool_md));
3521 return 0;
3522 }
3523
3524 warn_if_metadata_device_too_big(pool->md_dev);
3525 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
3526 dm_device_name(pool->pool_md),
3527 sb_metadata_dev_size, metadata_dev_size);
3528
3529 if (get_pool_mode(pool) == PM_OUT_OF_METADATA_SPACE)
3530 set_pool_mode(pool, PM_WRITE);
3531
3532 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
3533 if (r) {
3534 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
3535 return r;
3536 }
3537
3538 *need_commit = true;
3539 }
3540
3541 return 0;
3542}
3543
3544/*
3545 * Retrieves the number of blocks of the data device from
3546 * the superblock and compares it to the actual device size,
3547 * thus resizing the data device in case it has grown.
3548 *
3549 * This both copes with opening preallocated data devices in the ctr
3550 * being followed by a resume
3551 * -and-
3552 * calling the resume method individually after userspace has
3553 * grown the data device in reaction to a table event.
3554 */
3555static int pool_preresume(struct dm_target *ti)
3556{
3557 int r;
3558 bool need_commit1, need_commit2;
3559 struct pool_c *pt = ti->private;
3560 struct pool *pool = pt->pool;
3561
3562 /*
3563 * Take control of the pool object.
3564 */
3565 r = bind_control_target(pool, ti);
3566 if (r)
3567 return r;
3568
3569 r = maybe_resize_data_dev(ti, &need_commit1);
3570 if (r)
3571 return r;
3572
3573 r = maybe_resize_metadata_dev(ti, &need_commit2);
3574 if (r)
3575 return r;
3576
3577 if (need_commit1 || need_commit2)
3578 (void) commit(pool);
3579
3580 return 0;
3581}
3582
3583static void pool_suspend_active_thins(struct pool *pool)
3584{
3585 struct thin_c *tc;
3586
3587 /* Suspend all active thin devices */
3588 tc = get_first_thin(pool);
3589 while (tc) {
3590 dm_internal_suspend_noflush(tc->thin_md);
3591 tc = get_next_thin(pool, tc);
3592 }
3593}
3594
3595static void pool_resume_active_thins(struct pool *pool)
3596{
3597 struct thin_c *tc;
3598
3599 /* Resume all active thin devices */
3600 tc = get_first_thin(pool);
3601 while (tc) {
3602 dm_internal_resume(tc->thin_md);
3603 tc = get_next_thin(pool, tc);
3604 }
3605}
3606
3607static void pool_resume(struct dm_target *ti)
3608{
3609 struct pool_c *pt = ti->private;
3610 struct pool *pool = pt->pool;
3611
3612 /*
3613 * Must requeue active_thins' bios and then resume
3614 * active_thins _before_ clearing 'suspend' flag.
3615 */
3616 requeue_bios(pool);
3617 pool_resume_active_thins(pool);
3618
3619 spin_lock_irq(&pool->lock);
3620 pool->low_water_triggered = false;
3621 pool->suspended = false;
3622 spin_unlock_irq(&pool->lock);
3623
3624 do_waker(&pool->waker.work);
3625}
3626
3627static void pool_presuspend(struct dm_target *ti)
3628{
3629 struct pool_c *pt = ti->private;
3630 struct pool *pool = pt->pool;
3631
3632 spin_lock_irq(&pool->lock);
3633 pool->suspended = true;
3634 spin_unlock_irq(&pool->lock);
3635
3636 pool_suspend_active_thins(pool);
3637}
3638
3639static void pool_presuspend_undo(struct dm_target *ti)
3640{
3641 struct pool_c *pt = ti->private;
3642 struct pool *pool = pt->pool;
3643
3644 pool_resume_active_thins(pool);
3645
3646 spin_lock_irq(&pool->lock);
3647 pool->suspended = false;
3648 spin_unlock_irq(&pool->lock);
3649}
3650
3651static void pool_postsuspend(struct dm_target *ti)
3652{
3653 struct pool_c *pt = ti->private;
3654 struct pool *pool = pt->pool;
3655
3656 cancel_delayed_work_sync(&pool->waker);
3657 cancel_delayed_work_sync(&pool->no_space_timeout);
3658 flush_workqueue(pool->wq);
3659 (void) commit(pool);
3660}
3661
3662static int check_arg_count(unsigned argc, unsigned args_required)
3663{
3664 if (argc != args_required) {
3665 DMWARN("Message received with %u arguments instead of %u.",
3666 argc, args_required);
3667 return -EINVAL;
3668 }
3669
3670 return 0;
3671}
3672
3673static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
3674{
3675 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
3676 *dev_id <= MAX_DEV_ID)
3677 return 0;
3678
3679 if (warning)
3680 DMWARN("Message received with invalid device id: %s", arg);
3681
3682 return -EINVAL;
3683}
3684
3685static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
3686{
3687 dm_thin_id dev_id;
3688 int r;
3689
3690 r = check_arg_count(argc, 2);
3691 if (r)
3692 return r;
3693
3694 r = read_dev_id(argv[1], &dev_id, 1);
3695 if (r)
3696 return r;
3697
3698 r = dm_pool_create_thin(pool->pmd, dev_id);
3699 if (r) {
3700 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
3701 argv[1]);
3702 return r;
3703 }
3704
3705 return 0;
3706}
3707
3708static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3709{
3710 dm_thin_id dev_id;
3711 dm_thin_id origin_dev_id;
3712 int r;
3713
3714 r = check_arg_count(argc, 3);
3715 if (r)
3716 return r;
3717
3718 r = read_dev_id(argv[1], &dev_id, 1);
3719 if (r)
3720 return r;
3721
3722 r = read_dev_id(argv[2], &origin_dev_id, 1);
3723 if (r)
3724 return r;
3725
3726 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
3727 if (r) {
3728 DMWARN("Creation of new snapshot %s of device %s failed.",
3729 argv[1], argv[2]);
3730 return r;
3731 }
3732
3733 return 0;
3734}
3735
3736static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
3737{
3738 dm_thin_id dev_id;
3739 int r;
3740
3741 r = check_arg_count(argc, 2);
3742 if (r)
3743 return r;
3744
3745 r = read_dev_id(argv[1], &dev_id, 1);
3746 if (r)
3747 return r;
3748
3749 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
3750 if (r)
3751 DMWARN("Deletion of thin device %s failed.", argv[1]);
3752
3753 return r;
3754}
3755
3756static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
3757{
3758 dm_thin_id old_id, new_id;
3759 int r;
3760
3761 r = check_arg_count(argc, 3);
3762 if (r)
3763 return r;
3764
3765 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
3766 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
3767 return -EINVAL;
3768 }
3769
3770 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
3771 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
3772 return -EINVAL;
3773 }
3774
3775 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
3776 if (r) {
3777 DMWARN("Failed to change transaction id from %s to %s.",
3778 argv[1], argv[2]);
3779 return r;
3780 }
3781
3782 return 0;
3783}
3784
3785static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3786{
3787 int r;
3788
3789 r = check_arg_count(argc, 1);
3790 if (r)
3791 return r;
3792
3793 (void) commit(pool);
3794
3795 r = dm_pool_reserve_metadata_snap(pool->pmd);
3796 if (r)
3797 DMWARN("reserve_metadata_snap message failed.");
3798
3799 return r;
3800}
3801
3802static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3803{
3804 int r;
3805
3806 r = check_arg_count(argc, 1);
3807 if (r)
3808 return r;
3809
3810 r = dm_pool_release_metadata_snap(pool->pmd);
3811 if (r)
3812 DMWARN("release_metadata_snap message failed.");
3813
3814 return r;
3815}
3816
3817/*
3818 * Messages supported:
3819 * create_thin <dev_id>
3820 * create_snap <dev_id> <origin_id>
3821 * delete <dev_id>
3822 * set_transaction_id <current_trans_id> <new_trans_id>
3823 * reserve_metadata_snap
3824 * release_metadata_snap
3825 */
3826static int pool_message(struct dm_target *ti, unsigned argc, char **argv,
3827 char *result, unsigned maxlen)
3828{
3829 int r = -EINVAL;
3830 struct pool_c *pt = ti->private;
3831 struct pool *pool = pt->pool;
3832
3833 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE) {
3834 DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode",
3835 dm_device_name(pool->pool_md));
3836 return -EOPNOTSUPP;
3837 }
3838
3839 if (!strcasecmp(argv[0], "create_thin"))
3840 r = process_create_thin_mesg(argc, argv, pool);
3841
3842 else if (!strcasecmp(argv[0], "create_snap"))
3843 r = process_create_snap_mesg(argc, argv, pool);
3844
3845 else if (!strcasecmp(argv[0], "delete"))
3846 r = process_delete_mesg(argc, argv, pool);
3847
3848 else if (!strcasecmp(argv[0], "set_transaction_id"))
3849 r = process_set_transaction_id_mesg(argc, argv, pool);
3850
3851 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
3852 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
3853
3854 else if (!strcasecmp(argv[0], "release_metadata_snap"))
3855 r = process_release_metadata_snap_mesg(argc, argv, pool);
3856
3857 else
3858 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
3859
3860 if (!r)
3861 (void) commit(pool);
3862
3863 return r;
3864}
3865
3866static void emit_flags(struct pool_features *pf, char *result,
3867 unsigned sz, unsigned maxlen)
3868{
3869 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
3870 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
3871 pf->error_if_no_space;
3872 DMEMIT("%u ", count);
3873
3874 if (!pf->zero_new_blocks)
3875 DMEMIT("skip_block_zeroing ");
3876
3877 if (!pf->discard_enabled)
3878 DMEMIT("ignore_discard ");
3879
3880 if (!pf->discard_passdown)
3881 DMEMIT("no_discard_passdown ");
3882
3883 if (pf->mode == PM_READ_ONLY)
3884 DMEMIT("read_only ");
3885
3886 if (pf->error_if_no_space)
3887 DMEMIT("error_if_no_space ");
3888}
3889
3890/*
3891 * Status line is:
3892 * <transaction id> <used metadata sectors>/<total metadata sectors>
3893 * <used data sectors>/<total data sectors> <held metadata root>
3894 * <pool mode> <discard config> <no space config> <needs_check>
3895 */
3896static void pool_status(struct dm_target *ti, status_type_t type,
3897 unsigned status_flags, char *result, unsigned maxlen)
3898{
3899 int r;
3900 unsigned sz = 0;
3901 uint64_t transaction_id;
3902 dm_block_t nr_free_blocks_data;
3903 dm_block_t nr_free_blocks_metadata;
3904 dm_block_t nr_blocks_data;
3905 dm_block_t nr_blocks_metadata;
3906 dm_block_t held_root;
3907 enum pool_mode mode;
3908 char buf[BDEVNAME_SIZE];
3909 char buf2[BDEVNAME_SIZE];
3910 struct pool_c *pt = ti->private;
3911 struct pool *pool = pt->pool;
3912
3913 switch (type) {
3914 case STATUSTYPE_INFO:
3915 if (get_pool_mode(pool) == PM_FAIL) {
3916 DMEMIT("Fail");
3917 break;
3918 }
3919
3920 /* Commit to ensure statistics aren't out-of-date */
3921 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3922 (void) commit(pool);
3923
3924 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
3925 if (r) {
3926 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
3927 dm_device_name(pool->pool_md), r);
3928 goto err;
3929 }
3930
3931 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
3932 if (r) {
3933 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
3934 dm_device_name(pool->pool_md), r);
3935 goto err;
3936 }
3937
3938 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
3939 if (r) {
3940 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
3941 dm_device_name(pool->pool_md), r);
3942 goto err;
3943 }
3944
3945 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
3946 if (r) {
3947 DMERR("%s: dm_pool_get_free_block_count returned %d",
3948 dm_device_name(pool->pool_md), r);
3949 goto err;
3950 }
3951
3952 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
3953 if (r) {
3954 DMERR("%s: dm_pool_get_data_dev_size returned %d",
3955 dm_device_name(pool->pool_md), r);
3956 goto err;
3957 }
3958
3959 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
3960 if (r) {
3961 DMERR("%s: dm_pool_get_metadata_snap returned %d",
3962 dm_device_name(pool->pool_md), r);
3963 goto err;
3964 }
3965
3966 DMEMIT("%llu %llu/%llu %llu/%llu ",
3967 (unsigned long long)transaction_id,
3968 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3969 (unsigned long long)nr_blocks_metadata,
3970 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
3971 (unsigned long long)nr_blocks_data);
3972
3973 if (held_root)
3974 DMEMIT("%llu ", held_root);
3975 else
3976 DMEMIT("- ");
3977
3978 mode = get_pool_mode(pool);
3979 if (mode == PM_OUT_OF_DATA_SPACE)
3980 DMEMIT("out_of_data_space ");
3981 else if (is_read_only_pool_mode(mode))
3982 DMEMIT("ro ");
3983 else
3984 DMEMIT("rw ");
3985
3986 if (!pool->pf.discard_enabled)
3987 DMEMIT("ignore_discard ");
3988 else if (pool->pf.discard_passdown)
3989 DMEMIT("discard_passdown ");
3990 else
3991 DMEMIT("no_discard_passdown ");
3992
3993 if (pool->pf.error_if_no_space)
3994 DMEMIT("error_if_no_space ");
3995 else
3996 DMEMIT("queue_if_no_space ");
3997
3998 if (dm_pool_metadata_needs_check(pool->pmd))
3999 DMEMIT("needs_check ");
4000 else
4001 DMEMIT("- ");
4002
4003 DMEMIT("%llu ", (unsigned long long)calc_metadata_threshold(pt));
4004
4005 break;
4006
4007 case STATUSTYPE_TABLE:
4008 DMEMIT("%s %s %lu %llu ",
4009 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
4010 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
4011 (unsigned long)pool->sectors_per_block,
4012 (unsigned long long)pt->low_water_blocks);
4013 emit_flags(&pt->requested_pf, result, sz, maxlen);
4014 break;
4015 }
4016 return;
4017
4018err:
4019 DMEMIT("Error");
4020}
4021
4022static int pool_iterate_devices(struct dm_target *ti,
4023 iterate_devices_callout_fn fn, void *data)
4024{
4025 struct pool_c *pt = ti->private;
4026
4027 return fn(ti, pt->data_dev, 0, ti->len, data);
4028}
4029
4030static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
4031{
4032 struct pool_c *pt = ti->private;
4033 struct pool *pool = pt->pool;
4034 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
4035
4036 /*
4037 * If max_sectors is smaller than pool->sectors_per_block adjust it
4038 * to the highest possible power-of-2 factor of pool->sectors_per_block.
4039 * This is especially beneficial when the pool's data device is a RAID
4040 * device that has a full stripe width that matches pool->sectors_per_block
4041 * -- because even though partial RAID stripe-sized IOs will be issued to a
4042 * single RAID stripe; when aggregated they will end on a full RAID stripe
4043 * boundary.. which avoids additional partial RAID stripe writes cascading
4044 */
4045 if (limits->max_sectors < pool->sectors_per_block) {
4046 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
4047 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
4048 limits->max_sectors--;
4049 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
4050 }
4051 }
4052
4053 /*
4054 * If the system-determined stacked limits are compatible with the
4055 * pool's blocksize (io_opt is a factor) do not override them.
4056 */
4057 if (io_opt_sectors < pool->sectors_per_block ||
4058 !is_factor(io_opt_sectors, pool->sectors_per_block)) {
4059 if (is_factor(pool->sectors_per_block, limits->max_sectors))
4060 blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT);
4061 else
4062 blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);
4063 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
4064 }
4065
4066 /*
4067 * pt->adjusted_pf is a staging area for the actual features to use.
4068 * They get transferred to the live pool in bind_control_target()
4069 * called from pool_preresume().
4070 */
4071 if (!pt->adjusted_pf.discard_enabled) {
4072 /*
4073 * Must explicitly disallow stacking discard limits otherwise the
4074 * block layer will stack them if pool's data device has support.
4075 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
4076 * user to see that, so make sure to set all discard limits to 0.
4077 */
4078 limits->discard_granularity = 0;
4079 return;
4080 }
4081
4082 disable_passdown_if_not_supported(pt);
4083
4084 /*
4085 * The pool uses the same discard limits as the underlying data
4086 * device. DM core has already set this up.
4087 */
4088}
4089
4090static struct target_type pool_target = {
4091 .name = "thin-pool",
4092 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
4093 DM_TARGET_IMMUTABLE,
4094 .version = {1, 22, 0},
4095 .module = THIS_MODULE,
4096 .ctr = pool_ctr,
4097 .dtr = pool_dtr,
4098 .map = pool_map,
4099 .presuspend = pool_presuspend,
4100 .presuspend_undo = pool_presuspend_undo,
4101 .postsuspend = pool_postsuspend,
4102 .preresume = pool_preresume,
4103 .resume = pool_resume,
4104 .message = pool_message,
4105 .status = pool_status,
4106 .iterate_devices = pool_iterate_devices,
4107 .io_hints = pool_io_hints,
4108};
4109
4110/*----------------------------------------------------------------
4111 * Thin target methods
4112 *--------------------------------------------------------------*/
4113static void thin_get(struct thin_c *tc)
4114{
4115 refcount_inc(&tc->refcount);
4116}
4117
4118static void thin_put(struct thin_c *tc)
4119{
4120 if (refcount_dec_and_test(&tc->refcount))
4121 complete(&tc->can_destroy);
4122}
4123
4124static void thin_dtr(struct dm_target *ti)
4125{
4126 struct thin_c *tc = ti->private;
4127
4128 spin_lock_irq(&tc->pool->lock);
4129 list_del_rcu(&tc->list);
4130 spin_unlock_irq(&tc->pool->lock);
4131 synchronize_rcu();
4132
4133 thin_put(tc);
4134 wait_for_completion(&tc->can_destroy);
4135
4136 mutex_lock(&dm_thin_pool_table.mutex);
4137
4138 __pool_dec(tc->pool);
4139 dm_pool_close_thin_device(tc->td);
4140 dm_put_device(ti, tc->pool_dev);
4141 if (tc->origin_dev)
4142 dm_put_device(ti, tc->origin_dev);
4143 kfree(tc);
4144
4145 mutex_unlock(&dm_thin_pool_table.mutex);
4146}
4147
4148/*
4149 * Thin target parameters:
4150 *
4151 * <pool_dev> <dev_id> [origin_dev]
4152 *
4153 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
4154 * dev_id: the internal device identifier
4155 * origin_dev: a device external to the pool that should act as the origin
4156 *
4157 * If the pool device has discards disabled, they get disabled for the thin
4158 * device as well.
4159 */
4160static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
4161{
4162 int r;
4163 struct thin_c *tc;
4164 struct dm_dev *pool_dev, *origin_dev;
4165 struct mapped_device *pool_md;
4166
4167 mutex_lock(&dm_thin_pool_table.mutex);
4168
4169 if (argc != 2 && argc != 3) {
4170 ti->error = "Invalid argument count";
4171 r = -EINVAL;
4172 goto out_unlock;
4173 }
4174
4175 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
4176 if (!tc) {
4177 ti->error = "Out of memory";
4178 r = -ENOMEM;
4179 goto out_unlock;
4180 }
4181 tc->thin_md = dm_table_get_md(ti->table);
4182 spin_lock_init(&tc->lock);
4183 INIT_LIST_HEAD(&tc->deferred_cells);
4184 bio_list_init(&tc->deferred_bio_list);
4185 bio_list_init(&tc->retry_on_resume_list);
4186 tc->sort_bio_list = RB_ROOT;
4187
4188 if (argc == 3) {
4189 if (!strcmp(argv[0], argv[2])) {
4190 ti->error = "Error setting origin device";
4191 r = -EINVAL;
4192 goto bad_origin_dev;
4193 }
4194
4195 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
4196 if (r) {
4197 ti->error = "Error opening origin device";
4198 goto bad_origin_dev;
4199 }
4200 tc->origin_dev = origin_dev;
4201 }
4202
4203 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
4204 if (r) {
4205 ti->error = "Error opening pool device";
4206 goto bad_pool_dev;
4207 }
4208 tc->pool_dev = pool_dev;
4209
4210 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
4211 ti->error = "Invalid device id";
4212 r = -EINVAL;
4213 goto bad_common;
4214 }
4215
4216 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
4217 if (!pool_md) {
4218 ti->error = "Couldn't get pool mapped device";
4219 r = -EINVAL;
4220 goto bad_common;
4221 }
4222
4223 tc->pool = __pool_table_lookup(pool_md);
4224 if (!tc->pool) {
4225 ti->error = "Couldn't find pool object";
4226 r = -EINVAL;
4227 goto bad_pool_lookup;
4228 }
4229 __pool_inc(tc->pool);
4230
4231 if (get_pool_mode(tc->pool) == PM_FAIL) {
4232 ti->error = "Couldn't open thin device, Pool is in fail mode";
4233 r = -EINVAL;
4234 goto bad_pool;
4235 }
4236
4237 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
4238 if (r) {
4239 ti->error = "Couldn't open thin internal device";
4240 goto bad_pool;
4241 }
4242
4243 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
4244 if (r)
4245 goto bad;
4246
4247 ti->num_flush_bios = 1;
4248 ti->flush_supported = true;
4249 ti->per_io_data_size = sizeof(struct dm_thin_endio_hook);
4250
4251 /* In case the pool supports discards, pass them on. */
4252 if (tc->pool->pf.discard_enabled) {
4253 ti->discards_supported = true;
4254 ti->num_discard_bios = 1;
4255 }
4256
4257 mutex_unlock(&dm_thin_pool_table.mutex);
4258
4259 spin_lock_irq(&tc->pool->lock);
4260 if (tc->pool->suspended) {
4261 spin_unlock_irq(&tc->pool->lock);
4262 mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */
4263 ti->error = "Unable to activate thin device while pool is suspended";
4264 r = -EINVAL;
4265 goto bad;
4266 }
4267 refcount_set(&tc->refcount, 1);
4268 init_completion(&tc->can_destroy);
4269 list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
4270 spin_unlock_irq(&tc->pool->lock);
4271 /*
4272 * This synchronize_rcu() call is needed here otherwise we risk a
4273 * wake_worker() call finding no bios to process (because the newly
4274 * added tc isn't yet visible). So this reduces latency since we
4275 * aren't then dependent on the periodic commit to wake_worker().
4276 */
4277 synchronize_rcu();
4278
4279 dm_put(pool_md);
4280
4281 return 0;
4282
4283bad:
4284 dm_pool_close_thin_device(tc->td);
4285bad_pool:
4286 __pool_dec(tc->pool);
4287bad_pool_lookup:
4288 dm_put(pool_md);
4289bad_common:
4290 dm_put_device(ti, tc->pool_dev);
4291bad_pool_dev:
4292 if (tc->origin_dev)
4293 dm_put_device(ti, tc->origin_dev);
4294bad_origin_dev:
4295 kfree(tc);
4296out_unlock:
4297 mutex_unlock(&dm_thin_pool_table.mutex);
4298
4299 return r;
4300}
4301
4302static int thin_map(struct dm_target *ti, struct bio *bio)
4303{
4304 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
4305
4306 return thin_bio_map(ti, bio);
4307}
4308
4309static int thin_endio(struct dm_target *ti, struct bio *bio,
4310 blk_status_t *err)
4311{
4312 unsigned long flags;
4313 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
4314 struct list_head work;
4315 struct dm_thin_new_mapping *m, *tmp;
4316 struct pool *pool = h->tc->pool;
4317
4318 if (h->shared_read_entry) {
4319 INIT_LIST_HEAD(&work);
4320 dm_deferred_entry_dec(h->shared_read_entry, &work);
4321
4322 spin_lock_irqsave(&pool->lock, flags);
4323 list_for_each_entry_safe(m, tmp, &work, list) {
4324 list_del(&m->list);
4325 __complete_mapping_preparation(m);
4326 }
4327 spin_unlock_irqrestore(&pool->lock, flags);
4328 }
4329
4330 if (h->all_io_entry) {
4331 INIT_LIST_HEAD(&work);
4332 dm_deferred_entry_dec(h->all_io_entry, &work);
4333 if (!list_empty(&work)) {
4334 spin_lock_irqsave(&pool->lock, flags);
4335 list_for_each_entry_safe(m, tmp, &work, list)
4336 list_add_tail(&m->list, &pool->prepared_discards);
4337 spin_unlock_irqrestore(&pool->lock, flags);
4338 wake_worker(pool);
4339 }
4340 }
4341
4342 if (h->cell)
4343 cell_defer_no_holder(h->tc, h->cell);
4344
4345 return DM_ENDIO_DONE;
4346}
4347
4348static void thin_presuspend(struct dm_target *ti)
4349{
4350 struct thin_c *tc = ti->private;
4351
4352 if (dm_noflush_suspending(ti))
4353 noflush_work(tc, do_noflush_start);
4354}
4355
4356static void thin_postsuspend(struct dm_target *ti)
4357{
4358 struct thin_c *tc = ti->private;
4359
4360 /*
4361 * The dm_noflush_suspending flag has been cleared by now, so
4362 * unfortunately we must always run this.
4363 */
4364 noflush_work(tc, do_noflush_stop);
4365}
4366
4367static int thin_preresume(struct dm_target *ti)
4368{
4369 struct thin_c *tc = ti->private;
4370
4371 if (tc->origin_dev)
4372 tc->origin_size = get_dev_size(tc->origin_dev->bdev);
4373
4374 return 0;
4375}
4376
4377/*
4378 * <nr mapped sectors> <highest mapped sector>
4379 */
4380static void thin_status(struct dm_target *ti, status_type_t type,
4381 unsigned status_flags, char *result, unsigned maxlen)
4382{
4383 int r;
4384 ssize_t sz = 0;
4385 dm_block_t mapped, highest;
4386 char buf[BDEVNAME_SIZE];
4387 struct thin_c *tc = ti->private;
4388
4389 if (get_pool_mode(tc->pool) == PM_FAIL) {
4390 DMEMIT("Fail");
4391 return;
4392 }
4393
4394 if (!tc->td)
4395 DMEMIT("-");
4396 else {
4397 switch (type) {
4398 case STATUSTYPE_INFO:
4399 r = dm_thin_get_mapped_count(tc->td, &mapped);
4400 if (r) {
4401 DMERR("dm_thin_get_mapped_count returned %d", r);
4402 goto err;
4403 }
4404
4405 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
4406 if (r < 0) {
4407 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
4408 goto err;
4409 }
4410
4411 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
4412 if (r)
4413 DMEMIT("%llu", ((highest + 1) *
4414 tc->pool->sectors_per_block) - 1);
4415 else
4416 DMEMIT("-");
4417 break;
4418
4419 case STATUSTYPE_TABLE:
4420 DMEMIT("%s %lu",
4421 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
4422 (unsigned long) tc->dev_id);
4423 if (tc->origin_dev)
4424 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
4425 break;
4426 }
4427 }
4428
4429 return;
4430
4431err:
4432 DMEMIT("Error");
4433}
4434
4435static int thin_iterate_devices(struct dm_target *ti,
4436 iterate_devices_callout_fn fn, void *data)
4437{
4438 sector_t blocks;
4439 struct thin_c *tc = ti->private;
4440 struct pool *pool = tc->pool;
4441
4442 /*
4443 * We can't call dm_pool_get_data_dev_size() since that blocks. So
4444 * we follow a more convoluted path through to the pool's target.
4445 */
4446 if (!pool->ti)
4447 return 0; /* nothing is bound */
4448
4449 blocks = pool->ti->len;
4450 (void) sector_div(blocks, pool->sectors_per_block);
4451 if (blocks)
4452 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
4453
4454 return 0;
4455}
4456
4457static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
4458{
4459 struct thin_c *tc = ti->private;
4460 struct pool *pool = tc->pool;
4461
4462 if (!pool->pf.discard_enabled)
4463 return;
4464
4465 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
4466 limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */
4467}
4468
4469static struct target_type thin_target = {
4470 .name = "thin",
4471 .version = {1, 22, 0},
4472 .module = THIS_MODULE,
4473 .ctr = thin_ctr,
4474 .dtr = thin_dtr,
4475 .map = thin_map,
4476 .end_io = thin_endio,
4477 .preresume = thin_preresume,
4478 .presuspend = thin_presuspend,
4479 .postsuspend = thin_postsuspend,
4480 .status = thin_status,
4481 .iterate_devices = thin_iterate_devices,
4482 .io_hints = thin_io_hints,
4483};
4484
4485/*----------------------------------------------------------------*/
4486
4487static int __init dm_thin_init(void)
4488{
4489 int r = -ENOMEM;
4490
4491 pool_table_init();
4492
4493 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
4494 if (!_new_mapping_cache)
4495 return r;
4496
4497 r = dm_register_target(&thin_target);
4498 if (r)
4499 goto bad_new_mapping_cache;
4500
4501 r = dm_register_target(&pool_target);
4502 if (r)
4503 goto bad_thin_target;
4504
4505 return 0;
4506
4507bad_thin_target:
4508 dm_unregister_target(&thin_target);
4509bad_new_mapping_cache:
4510 kmem_cache_destroy(_new_mapping_cache);
4511
4512 return r;
4513}
4514
4515static void dm_thin_exit(void)
4516{
4517 dm_unregister_target(&thin_target);
4518 dm_unregister_target(&pool_target);
4519
4520 kmem_cache_destroy(_new_mapping_cache);
4521
4522 pool_table_exit();
4523}
4524
4525module_init(dm_thin_init);
4526module_exit(dm_thin_exit);
4527
4528module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);
4529MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
4530
4531MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
4532MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
4533MODULE_LICENSE("GPL");