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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// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2011-2012 Red Hat UK.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm-thin-metadata.h"
9#include "dm-bio-prison-v1.h"
10#include "dm.h"
11
12#include <linux/device-mapper.h>
13#include <linux/dm-io.h>
14#include <linux/dm-kcopyd.h>
15#include <linux/jiffies.h>
16#include <linux/log2.h>
17#include <linux/list.h>
18#include <linux/rculist.h>
19#include <linux/init.h>
20#include <linux/module.h>
21#include <linux/slab.h>
22#include <linux/vmalloc.h>
23#include <linux/sort.h>
24#include <linux/rbtree.h>
25
26#define DM_MSG_PREFIX "thin"
27
28/*
29 * Tunable constants
30 */
31#define ENDIO_HOOK_POOL_SIZE 1024
32#define MAPPING_POOL_SIZE 1024
33#define COMMIT_PERIOD HZ
34#define NO_SPACE_TIMEOUT_SECS 60
35
36static unsigned int no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
37
38DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
39 "A percentage of time allocated for copy on write");
40
41/*
42 * The block size of the device holding pool data must be
43 * between 64KB and 1GB.
44 */
45#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
46#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
47
48/*
49 * Device id is restricted to 24 bits.
50 */
51#define MAX_DEV_ID ((1 << 24) - 1)
52
53/*
54 * How do we handle breaking sharing of data blocks?
55 * =================================================
56 *
57 * We use a standard copy-on-write btree to store the mappings for the
58 * devices (note I'm talking about copy-on-write of the metadata here, not
59 * the data). When you take an internal snapshot you clone the root node
60 * of the origin btree. After this there is no concept of an origin or a
61 * snapshot. They are just two device trees that happen to point to the
62 * same data blocks.
63 *
64 * When we get a write in we decide if it's to a shared data block using
65 * some timestamp magic. If it is, we have to break sharing.
66 *
67 * Let's say we write to a shared block in what was the origin. The
68 * steps are:
69 *
70 * i) plug io further to this physical block. (see bio_prison code).
71 *
72 * ii) quiesce any read io to that shared data block. Obviously
73 * including all devices that share this block. (see dm_deferred_set code)
74 *
75 * iii) copy the data block to a newly allocate block. This step can be
76 * missed out if the io covers the block. (schedule_copy).
77 *
78 * iv) insert the new mapping into the origin's btree
79 * (process_prepared_mapping). This act of inserting breaks some
80 * sharing of btree nodes between the two devices. Breaking sharing only
81 * effects the btree of that specific device. Btrees for the other
82 * devices that share the block never change. The btree for the origin
83 * device as it was after the last commit is untouched, ie. we're using
84 * persistent data structures in the functional programming sense.
85 *
86 * v) unplug io to this physical block, including the io that triggered
87 * the breaking of sharing.
88 *
89 * Steps (ii) and (iii) occur in parallel.
90 *
91 * The metadata _doesn't_ need to be committed before the io continues. We
92 * get away with this because the io is always written to a _new_ block.
93 * If there's a crash, then:
94 *
95 * - The origin mapping will point to the old origin block (the shared
96 * one). This will contain the data as it was before the io that triggered
97 * the breaking of sharing came in.
98 *
99 * - The snap mapping still points to the old block. As it would after
100 * the commit.
101 *
102 * The downside of this scheme is the timestamp magic isn't perfect, and
103 * will continue to think that data block in the snapshot device is shared
104 * even after the write to the origin has broken sharing. I suspect data
105 * blocks will typically be shared by many different devices, so we're
106 * breaking sharing n + 1 times, rather than n, where n is the number of
107 * devices that reference this data block. At the moment I think the
108 * benefits far, far outweigh the disadvantages.
109 */
110
111/*----------------------------------------------------------------*/
112
113/*
114 * Key building.
115 */
116enum lock_space {
117 VIRTUAL,
118 PHYSICAL
119};
120
121static bool build_key(struct dm_thin_device *td, enum lock_space ls,
122 dm_block_t b, dm_block_t e, struct dm_cell_key *key)
123{
124 key->virtual = (ls == VIRTUAL);
125 key->dev = dm_thin_dev_id(td);
126 key->block_begin = b;
127 key->block_end = e;
128
129 return dm_cell_key_has_valid_range(key);
130}
131
132static void build_data_key(struct dm_thin_device *td, dm_block_t b,
133 struct dm_cell_key *key)
134{
135 (void) build_key(td, PHYSICAL, b, b + 1llu, key);
136}
137
138static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
139 struct dm_cell_key *key)
140{
141 (void) build_key(td, VIRTUAL, b, b + 1llu, key);
142}
143
144/*----------------------------------------------------------------*/
145
146#define THROTTLE_THRESHOLD (1 * HZ)
147
148struct throttle {
149 struct rw_semaphore lock;
150 unsigned long threshold;
151 bool throttle_applied;
152};
153
154static void throttle_init(struct throttle *t)
155{
156 init_rwsem(&t->lock);
157 t->throttle_applied = false;
158}
159
160static void throttle_work_start(struct throttle *t)
161{
162 t->threshold = jiffies + THROTTLE_THRESHOLD;
163}
164
165static void throttle_work_update(struct throttle *t)
166{
167 if (!t->throttle_applied && time_is_before_jiffies(t->threshold)) {
168 down_write(&t->lock);
169 t->throttle_applied = true;
170 }
171}
172
173static void throttle_work_complete(struct throttle *t)
174{
175 if (t->throttle_applied) {
176 t->throttle_applied = false;
177 up_write(&t->lock);
178 }
179}
180
181static void throttle_lock(struct throttle *t)
182{
183 down_read(&t->lock);
184}
185
186static void throttle_unlock(struct throttle *t)
187{
188 up_read(&t->lock);
189}
190
191/*----------------------------------------------------------------*/
192
193/*
194 * A pool device ties together a metadata device and a data device. It
195 * also provides the interface for creating and destroying internal
196 * devices.
197 */
198struct dm_thin_new_mapping;
199
200/*
201 * The pool runs in various modes. Ordered in degraded order for comparisons.
202 */
203enum pool_mode {
204 PM_WRITE, /* metadata may be changed */
205 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
206
207 /*
208 * Like READ_ONLY, except may switch back to WRITE on metadata resize. Reported as READ_ONLY.
209 */
210 PM_OUT_OF_METADATA_SPACE,
211 PM_READ_ONLY, /* metadata may not be changed */
212
213 PM_FAIL, /* all I/O fails */
214};
215
216struct pool_features {
217 enum pool_mode mode;
218
219 bool zero_new_blocks:1;
220 bool discard_enabled:1;
221 bool discard_passdown:1;
222 bool error_if_no_space:1;
223};
224
225struct thin_c;
226typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
227typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell);
228typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
229
230#define CELL_SORT_ARRAY_SIZE 8192
231
232struct pool {
233 struct list_head list;
234 struct dm_target *ti; /* Only set if a pool target is bound */
235
236 struct mapped_device *pool_md;
237 struct block_device *data_dev;
238 struct block_device *md_dev;
239 struct dm_pool_metadata *pmd;
240
241 dm_block_t low_water_blocks;
242 uint32_t sectors_per_block;
243 int sectors_per_block_shift;
244
245 struct pool_features pf;
246 bool low_water_triggered:1; /* A dm event has been sent */
247 bool suspended:1;
248 bool out_of_data_space:1;
249
250 struct dm_bio_prison *prison;
251 struct dm_kcopyd_client *copier;
252
253 struct work_struct worker;
254 struct workqueue_struct *wq;
255 struct throttle throttle;
256 struct delayed_work waker;
257 struct delayed_work no_space_timeout;
258
259 unsigned long last_commit_jiffies;
260 unsigned int ref_count;
261
262 spinlock_t lock;
263 struct bio_list deferred_flush_bios;
264 struct bio_list deferred_flush_completions;
265 struct list_head prepared_mappings;
266 struct list_head prepared_discards;
267 struct list_head prepared_discards_pt2;
268 struct list_head active_thins;
269
270 struct dm_deferred_set *shared_read_ds;
271 struct dm_deferred_set *all_io_ds;
272
273 struct dm_thin_new_mapping *next_mapping;
274
275 process_bio_fn process_bio;
276 process_bio_fn process_discard;
277
278 process_cell_fn process_cell;
279 process_cell_fn process_discard_cell;
280
281 process_mapping_fn process_prepared_mapping;
282 process_mapping_fn process_prepared_discard;
283 process_mapping_fn process_prepared_discard_pt2;
284
285 struct dm_bio_prison_cell **cell_sort_array;
286
287 mempool_t mapping_pool;
288};
289
290static void metadata_operation_failed(struct pool *pool, const char *op, int r);
291
292static enum pool_mode get_pool_mode(struct pool *pool)
293{
294 return pool->pf.mode;
295}
296
297static void notify_of_pool_mode_change(struct pool *pool)
298{
299 static const char *descs[] = {
300 "write",
301 "out-of-data-space",
302 "read-only",
303 "read-only",
304 "fail"
305 };
306 const char *extra_desc = NULL;
307 enum pool_mode mode = get_pool_mode(pool);
308
309 if (mode == PM_OUT_OF_DATA_SPACE) {
310 if (!pool->pf.error_if_no_space)
311 extra_desc = " (queue IO)";
312 else
313 extra_desc = " (error IO)";
314 }
315
316 dm_table_event(pool->ti->table);
317 DMINFO("%s: switching pool to %s%s mode",
318 dm_device_name(pool->pool_md),
319 descs[(int)mode], extra_desc ? : "");
320}
321
322/*
323 * Target context for a pool.
324 */
325struct pool_c {
326 struct dm_target *ti;
327 struct pool *pool;
328 struct dm_dev *data_dev;
329 struct dm_dev *metadata_dev;
330
331 dm_block_t low_water_blocks;
332 struct pool_features requested_pf; /* Features requested during table load */
333 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
334};
335
336/*
337 * Target context for a thin.
338 */
339struct thin_c {
340 struct list_head list;
341 struct dm_dev *pool_dev;
342 struct dm_dev *origin_dev;
343 sector_t origin_size;
344 dm_thin_id dev_id;
345
346 struct pool *pool;
347 struct dm_thin_device *td;
348 struct mapped_device *thin_md;
349
350 bool requeue_mode:1;
351 spinlock_t lock;
352 struct list_head deferred_cells;
353 struct bio_list deferred_bio_list;
354 struct bio_list retry_on_resume_list;
355 struct rb_root sort_bio_list; /* sorted list of deferred bios */
356
357 /*
358 * Ensures the thin is not destroyed until the worker has finished
359 * iterating the active_thins list.
360 */
361 refcount_t refcount;
362 struct completion can_destroy;
363};
364
365/*----------------------------------------------------------------*/
366
367static bool block_size_is_power_of_two(struct pool *pool)
368{
369 return pool->sectors_per_block_shift >= 0;
370}
371
372static sector_t block_to_sectors(struct pool *pool, dm_block_t b)
373{
374 return block_size_is_power_of_two(pool) ?
375 (b << pool->sectors_per_block_shift) :
376 (b * pool->sectors_per_block);
377}
378
379/*----------------------------------------------------------------*/
380
381struct discard_op {
382 struct thin_c *tc;
383 struct blk_plug plug;
384 struct bio *parent_bio;
385 struct bio *bio;
386};
387
388static void begin_discard(struct discard_op *op, struct thin_c *tc, struct bio *parent)
389{
390 BUG_ON(!parent);
391
392 op->tc = tc;
393 blk_start_plug(&op->plug);
394 op->parent_bio = parent;
395 op->bio = NULL;
396}
397
398static int issue_discard(struct discard_op *op, dm_block_t data_b, dm_block_t data_e)
399{
400 struct thin_c *tc = op->tc;
401 sector_t s = block_to_sectors(tc->pool, data_b);
402 sector_t len = block_to_sectors(tc->pool, data_e - data_b);
403
404 return __blkdev_issue_discard(tc->pool_dev->bdev, s, len, GFP_NOIO, &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 op->bio->bi_opf = REQ_OP_DISCARD;
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
464 return r;
465}
466
467static void cell_release(struct pool *pool,
468 struct dm_bio_prison_cell *cell,
469 struct bio_list *bios)
470{
471 dm_cell_release(pool->prison, cell, bios);
472 dm_bio_prison_free_cell(pool->prison, cell);
473}
474
475static void cell_visit_release(struct pool *pool,
476 void (*fn)(void *, struct dm_bio_prison_cell *),
477 void *context,
478 struct dm_bio_prison_cell *cell)
479{
480 dm_cell_visit_release(pool->prison, fn, context, cell);
481 dm_bio_prison_free_cell(pool->prison, cell);
482}
483
484static void cell_release_no_holder(struct pool *pool,
485 struct dm_bio_prison_cell *cell,
486 struct bio_list *bios)
487{
488 dm_cell_release_no_holder(pool->prison, cell, bios);
489 dm_bio_prison_free_cell(pool->prison, cell);
490}
491
492static void cell_error_with_code(struct pool *pool,
493 struct dm_bio_prison_cell *cell, blk_status_t error_code)
494{
495 dm_cell_error(pool->prison, cell, error_code);
496 dm_bio_prison_free_cell(pool->prison, cell);
497}
498
499static blk_status_t get_pool_io_error_code(struct pool *pool)
500{
501 return pool->out_of_data_space ? BLK_STS_NOSPC : BLK_STS_IOERR;
502}
503
504static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
505{
506 cell_error_with_code(pool, cell, get_pool_io_error_code(pool));
507}
508
509static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
510{
511 cell_error_with_code(pool, cell, 0);
512}
513
514static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
515{
516 cell_error_with_code(pool, cell, BLK_STS_DM_REQUEUE);
517}
518
519/*----------------------------------------------------------------*/
520
521/*
522 * A global list of pools that uses a struct mapped_device as a key.
523 */
524static struct dm_thin_pool_table {
525 struct mutex mutex;
526 struct list_head pools;
527} dm_thin_pool_table;
528
529static void pool_table_init(void)
530{
531 mutex_init(&dm_thin_pool_table.mutex);
532 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
533}
534
535static void pool_table_exit(void)
536{
537 mutex_destroy(&dm_thin_pool_table.mutex);
538}
539
540static void __pool_table_insert(struct pool *pool)
541{
542 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
543 list_add(&pool->list, &dm_thin_pool_table.pools);
544}
545
546static void __pool_table_remove(struct pool *pool)
547{
548 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
549 list_del(&pool->list);
550}
551
552static struct pool *__pool_table_lookup(struct mapped_device *md)
553{
554 struct pool *pool = NULL, *tmp;
555
556 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
557
558 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
559 if (tmp->pool_md == md) {
560 pool = tmp;
561 break;
562 }
563 }
564
565 return pool;
566}
567
568static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
569{
570 struct pool *pool = NULL, *tmp;
571
572 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
573
574 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
575 if (tmp->md_dev == md_dev) {
576 pool = tmp;
577 break;
578 }
579 }
580
581 return pool;
582}
583
584/*----------------------------------------------------------------*/
585
586struct dm_thin_endio_hook {
587 struct thin_c *tc;
588 struct dm_deferred_entry *shared_read_entry;
589 struct dm_deferred_entry *all_io_entry;
590 struct dm_thin_new_mapping *overwrite_mapping;
591 struct rb_node rb_node;
592 struct dm_bio_prison_cell *cell;
593};
594
595static void error_bio_list(struct bio_list *bios, blk_status_t error)
596{
597 struct bio *bio;
598
599 while ((bio = bio_list_pop(bios))) {
600 bio->bi_status = error;
601 bio_endio(bio);
602 }
603}
604
605static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master,
606 blk_status_t error)
607{
608 struct bio_list bios;
609
610 bio_list_init(&bios);
611
612 spin_lock_irq(&tc->lock);
613 bio_list_merge_init(&bios, master);
614 spin_unlock_irq(&tc->lock);
615
616 error_bio_list(&bios, error);
617}
618
619static void requeue_deferred_cells(struct thin_c *tc)
620{
621 struct pool *pool = tc->pool;
622 struct list_head cells;
623 struct dm_bio_prison_cell *cell, *tmp;
624
625 INIT_LIST_HEAD(&cells);
626
627 spin_lock_irq(&tc->lock);
628 list_splice_init(&tc->deferred_cells, &cells);
629 spin_unlock_irq(&tc->lock);
630
631 list_for_each_entry_safe(cell, tmp, &cells, user_list)
632 cell_requeue(pool, cell);
633}
634
635static void requeue_io(struct thin_c *tc)
636{
637 struct bio_list bios;
638
639 bio_list_init(&bios);
640
641 spin_lock_irq(&tc->lock);
642 bio_list_merge_init(&bios, &tc->deferred_bio_list);
643 bio_list_merge_init(&bios, &tc->retry_on_resume_list);
644 spin_unlock_irq(&tc->lock);
645
646 error_bio_list(&bios, BLK_STS_DM_REQUEUE);
647 requeue_deferred_cells(tc);
648}
649
650static void error_retry_list_with_code(struct pool *pool, blk_status_t error)
651{
652 struct thin_c *tc;
653
654 rcu_read_lock();
655 list_for_each_entry_rcu(tc, &pool->active_thins, list)
656 error_thin_bio_list(tc, &tc->retry_on_resume_list, error);
657 rcu_read_unlock();
658}
659
660static void error_retry_list(struct pool *pool)
661{
662 error_retry_list_with_code(pool, get_pool_io_error_code(pool));
663}
664
665/*
666 * This section of code contains the logic for processing a thin device's IO.
667 * Much of the code depends on pool object resources (lists, workqueues, etc)
668 * but most is exclusively called from the thin target rather than the thin-pool
669 * target.
670 */
671
672static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
673{
674 struct pool *pool = tc->pool;
675 sector_t block_nr = bio->bi_iter.bi_sector;
676
677 if (block_size_is_power_of_two(pool))
678 block_nr >>= pool->sectors_per_block_shift;
679 else
680 (void) sector_div(block_nr, pool->sectors_per_block);
681
682 return block_nr;
683}
684
685/*
686 * Returns the _complete_ blocks that this bio covers.
687 */
688static void get_bio_block_range(struct thin_c *tc, struct bio *bio,
689 dm_block_t *begin, dm_block_t *end)
690{
691 struct pool *pool = tc->pool;
692 sector_t b = bio->bi_iter.bi_sector;
693 sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT);
694
695 b += pool->sectors_per_block - 1ull; /* so we round up */
696
697 if (block_size_is_power_of_two(pool)) {
698 b >>= pool->sectors_per_block_shift;
699 e >>= pool->sectors_per_block_shift;
700 } else {
701 (void) sector_div(b, pool->sectors_per_block);
702 (void) sector_div(e, pool->sectors_per_block);
703 }
704
705 if (e < b) {
706 /* Can happen if the bio is within a single block. */
707 e = b;
708 }
709
710 *begin = b;
711 *end = e;
712}
713
714static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
715{
716 struct pool *pool = tc->pool;
717 sector_t bi_sector = bio->bi_iter.bi_sector;
718
719 bio_set_dev(bio, tc->pool_dev->bdev);
720 if (block_size_is_power_of_two(pool)) {
721 bio->bi_iter.bi_sector =
722 (block << pool->sectors_per_block_shift) |
723 (bi_sector & (pool->sectors_per_block - 1));
724 } else {
725 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
726 sector_div(bi_sector, pool->sectors_per_block);
727 }
728}
729
730static void remap_to_origin(struct thin_c *tc, struct bio *bio)
731{
732 bio_set_dev(bio, tc->origin_dev->bdev);
733}
734
735static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
736{
737 return op_is_flush(bio->bi_opf) &&
738 dm_thin_changed_this_transaction(tc->td);
739}
740
741static void inc_all_io_entry(struct pool *pool, struct bio *bio)
742{
743 struct dm_thin_endio_hook *h;
744
745 if (bio_op(bio) == REQ_OP_DISCARD)
746 return;
747
748 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
749 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
750}
751
752static void issue(struct thin_c *tc, struct bio *bio)
753{
754 struct pool *pool = tc->pool;
755
756 if (!bio_triggers_commit(tc, bio)) {
757 dm_submit_bio_remap(bio, NULL);
758 return;
759 }
760
761 /*
762 * Complete bio with an error if earlier I/O caused changes to
763 * the metadata that can't be committed e.g, due to I/O errors
764 * on the metadata device.
765 */
766 if (dm_thin_aborted_changes(tc->td)) {
767 bio_io_error(bio);
768 return;
769 }
770
771 /*
772 * Batch together any bios that trigger commits and then issue a
773 * single commit for them in process_deferred_bios().
774 */
775 spin_lock_irq(&pool->lock);
776 bio_list_add(&pool->deferred_flush_bios, bio);
777 spin_unlock_irq(&pool->lock);
778}
779
780static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
781{
782 remap_to_origin(tc, bio);
783 issue(tc, bio);
784}
785
786static void remap_and_issue(struct thin_c *tc, struct bio *bio,
787 dm_block_t block)
788{
789 remap(tc, bio, block);
790 issue(tc, bio);
791}
792
793/*----------------------------------------------------------------*/
794
795/*
796 * Bio endio functions.
797 */
798struct dm_thin_new_mapping {
799 struct list_head list;
800
801 bool pass_discard:1;
802 bool maybe_shared:1;
803
804 /*
805 * Track quiescing, copying and zeroing preparation actions. When this
806 * counter hits zero the block is prepared and can be inserted into the
807 * btree.
808 */
809 atomic_t prepare_actions;
810
811 blk_status_t status;
812 struct thin_c *tc;
813 dm_block_t virt_begin, virt_end;
814 dm_block_t data_block;
815 struct dm_bio_prison_cell *cell;
816
817 /*
818 * If the bio covers the whole area of a block then we can avoid
819 * zeroing or copying. Instead this bio is hooked. The bio will
820 * still be in the cell, so care has to be taken to avoid issuing
821 * the bio twice.
822 */
823 struct bio *bio;
824 bio_end_io_t *saved_bi_end_io;
825};
826
827static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
828{
829 struct pool *pool = m->tc->pool;
830
831 if (atomic_dec_and_test(&m->prepare_actions)) {
832 list_add_tail(&m->list, &pool->prepared_mappings);
833 wake_worker(pool);
834 }
835}
836
837static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
838{
839 unsigned long flags;
840 struct pool *pool = m->tc->pool;
841
842 spin_lock_irqsave(&pool->lock, flags);
843 __complete_mapping_preparation(m);
844 spin_unlock_irqrestore(&pool->lock, flags);
845}
846
847static void copy_complete(int read_err, unsigned long write_err, void *context)
848{
849 struct dm_thin_new_mapping *m = context;
850
851 m->status = read_err || write_err ? BLK_STS_IOERR : 0;
852 complete_mapping_preparation(m);
853}
854
855static void overwrite_endio(struct bio *bio)
856{
857 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
858 struct dm_thin_new_mapping *m = h->overwrite_mapping;
859
860 bio->bi_end_io = m->saved_bi_end_io;
861
862 m->status = bio->bi_status;
863 complete_mapping_preparation(m);
864}
865
866/*----------------------------------------------------------------*/
867
868/*
869 * Workqueue.
870 */
871
872/*
873 * Prepared mapping jobs.
874 */
875
876/*
877 * This sends the bios in the cell, except the original holder, back
878 * to the deferred_bios list.
879 */
880static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
881{
882 struct pool *pool = tc->pool;
883 unsigned long flags;
884 struct bio_list bios;
885
886 bio_list_init(&bios);
887 cell_release_no_holder(pool, cell, &bios);
888
889 if (!bio_list_empty(&bios)) {
890 spin_lock_irqsave(&tc->lock, flags);
891 bio_list_merge(&tc->deferred_bio_list, &bios);
892 spin_unlock_irqrestore(&tc->lock, flags);
893 wake_worker(pool);
894 }
895}
896
897static void thin_defer_bio(struct thin_c *tc, struct bio *bio);
898
899struct remap_info {
900 struct thin_c *tc;
901 struct bio_list defer_bios;
902 struct bio_list issue_bios;
903};
904
905static void __inc_remap_and_issue_cell(void *context,
906 struct dm_bio_prison_cell *cell)
907{
908 struct remap_info *info = context;
909 struct bio *bio;
910
911 while ((bio = bio_list_pop(&cell->bios))) {
912 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD)
913 bio_list_add(&info->defer_bios, bio);
914 else {
915 inc_all_io_entry(info->tc->pool, bio);
916
917 /*
918 * We can't issue the bios with the bio prison lock
919 * held, so we add them to a list to issue on
920 * return from this function.
921 */
922 bio_list_add(&info->issue_bios, bio);
923 }
924 }
925}
926
927static void inc_remap_and_issue_cell(struct thin_c *tc,
928 struct dm_bio_prison_cell *cell,
929 dm_block_t block)
930{
931 struct bio *bio;
932 struct remap_info info;
933
934 info.tc = tc;
935 bio_list_init(&info.defer_bios);
936 bio_list_init(&info.issue_bios);
937
938 /*
939 * We have to be careful to inc any bios we're about to issue
940 * before the cell is released, and avoid a race with new bios
941 * being added to the cell.
942 */
943 cell_visit_release(tc->pool, __inc_remap_and_issue_cell,
944 &info, cell);
945
946 while ((bio = bio_list_pop(&info.defer_bios)))
947 thin_defer_bio(tc, bio);
948
949 while ((bio = bio_list_pop(&info.issue_bios)))
950 remap_and_issue(info.tc, bio, block);
951}
952
953static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
954{
955 cell_error(m->tc->pool, m->cell);
956 list_del(&m->list);
957 mempool_free(m, &m->tc->pool->mapping_pool);
958}
959
960static void complete_overwrite_bio(struct thin_c *tc, struct bio *bio)
961{
962 struct pool *pool = tc->pool;
963
964 /*
965 * If the bio has the REQ_FUA flag set we must commit the metadata
966 * before signaling its completion.
967 */
968 if (!bio_triggers_commit(tc, bio)) {
969 bio_endio(bio);
970 return;
971 }
972
973 /*
974 * Complete bio with an error if earlier I/O caused changes to the
975 * metadata that can't be committed, e.g, due to I/O errors on the
976 * metadata device.
977 */
978 if (dm_thin_aborted_changes(tc->td)) {
979 bio_io_error(bio);
980 return;
981 }
982
983 /*
984 * Batch together any bios that trigger commits and then issue a
985 * single commit for them in process_deferred_bios().
986 */
987 spin_lock_irq(&pool->lock);
988 bio_list_add(&pool->deferred_flush_completions, bio);
989 spin_unlock_irq(&pool->lock);
990}
991
992static void process_prepared_mapping(struct dm_thin_new_mapping *m)
993{
994 struct thin_c *tc = m->tc;
995 struct pool *pool = tc->pool;
996 struct bio *bio = m->bio;
997 int r;
998
999 if (m->status) {
1000 cell_error(pool, m->cell);
1001 goto out;
1002 }
1003
1004 /*
1005 * Commit the prepared block into the mapping btree.
1006 * Any I/O for this block arriving after this point will get
1007 * remapped to it directly.
1008 */
1009 r = dm_thin_insert_block(tc->td, m->virt_begin, m->data_block);
1010 if (r) {
1011 metadata_operation_failed(pool, "dm_thin_insert_block", r);
1012 cell_error(pool, m->cell);
1013 goto out;
1014 }
1015
1016 /*
1017 * Release any bios held while the block was being provisioned.
1018 * If we are processing a write bio that completely covers the block,
1019 * we already processed it so can ignore it now when processing
1020 * the bios in the cell.
1021 */
1022 if (bio) {
1023 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
1024 complete_overwrite_bio(tc, bio);
1025 } else {
1026 inc_all_io_entry(tc->pool, m->cell->holder);
1027 remap_and_issue(tc, m->cell->holder, m->data_block);
1028 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
1029 }
1030
1031out:
1032 list_del(&m->list);
1033 mempool_free(m, &pool->mapping_pool);
1034}
1035
1036/*----------------------------------------------------------------*/
1037
1038static void free_discard_mapping(struct dm_thin_new_mapping *m)
1039{
1040 struct thin_c *tc = m->tc;
1041
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(NULL, 1, 0, GFP_NOIO);
1183 discard_parent->bi_end_io = passdown_endio;
1184 discard_parent->bi_private = m;
1185 if (m->maybe_shared)
1186 passdown_double_checking_shared_status(m, discard_parent);
1187 else {
1188 struct discard_op op;
1189
1190 begin_discard(&op, tc, discard_parent);
1191 r = issue_discard(&op, m->data_block, data_end);
1192 end_discard(&op, r);
1193 }
1194}
1195
1196static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m)
1197{
1198 int r;
1199 struct thin_c *tc = m->tc;
1200 struct pool *pool = tc->pool;
1201
1202 /*
1203 * The passdown has completed, so now we can decrement all those
1204 * unmapped blocks.
1205 */
1206 r = dm_pool_dec_data_range(pool->pmd, m->data_block,
1207 m->data_block + (m->virt_end - m->virt_begin));
1208 if (r) {
1209 metadata_operation_failed(pool, "dm_pool_dec_data_range", r);
1210 bio_io_error(m->bio);
1211 } else
1212 bio_endio(m->bio);
1213
1214 cell_defer_no_holder(tc, m->cell);
1215 mempool_free(m, &pool->mapping_pool);
1216}
1217
1218static void process_prepared(struct pool *pool, struct list_head *head,
1219 process_mapping_fn *fn)
1220{
1221 struct list_head maps;
1222 struct dm_thin_new_mapping *m, *tmp;
1223
1224 INIT_LIST_HEAD(&maps);
1225 spin_lock_irq(&pool->lock);
1226 list_splice_init(head, &maps);
1227 spin_unlock_irq(&pool->lock);
1228
1229 list_for_each_entry_safe(m, tmp, &maps, list)
1230 (*fn)(m);
1231}
1232
1233/*
1234 * Deferred bio jobs.
1235 */
1236static int io_overlaps_block(struct pool *pool, struct bio *bio)
1237{
1238 return bio->bi_iter.bi_size ==
1239 (pool->sectors_per_block << SECTOR_SHIFT);
1240}
1241
1242static int io_overwrites_block(struct pool *pool, struct bio *bio)
1243{
1244 return (bio_data_dir(bio) == WRITE) &&
1245 io_overlaps_block(pool, bio);
1246}
1247
1248static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
1249 bio_end_io_t *fn)
1250{
1251 *save = bio->bi_end_io;
1252 bio->bi_end_io = fn;
1253}
1254
1255static int ensure_next_mapping(struct pool *pool)
1256{
1257 if (pool->next_mapping)
1258 return 0;
1259
1260 pool->next_mapping = mempool_alloc(&pool->mapping_pool, GFP_ATOMIC);
1261
1262 return pool->next_mapping ? 0 : -ENOMEM;
1263}
1264
1265static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
1266{
1267 struct dm_thin_new_mapping *m = pool->next_mapping;
1268
1269 BUG_ON(!pool->next_mapping);
1270
1271 memset(m, 0, sizeof(struct dm_thin_new_mapping));
1272 INIT_LIST_HEAD(&m->list);
1273 m->bio = NULL;
1274
1275 pool->next_mapping = NULL;
1276
1277 return m;
1278}
1279
1280static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
1281 sector_t begin, sector_t end)
1282{
1283 struct dm_io_region to;
1284
1285 to.bdev = tc->pool_dev->bdev;
1286 to.sector = begin;
1287 to.count = end - begin;
1288
1289 dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
1290}
1291
1292static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
1293 dm_block_t data_begin,
1294 struct dm_thin_new_mapping *m)
1295{
1296 struct pool *pool = tc->pool;
1297 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1298
1299 h->overwrite_mapping = m;
1300 m->bio = bio;
1301 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
1302 inc_all_io_entry(pool, bio);
1303 remap_and_issue(tc, bio, data_begin);
1304}
1305
1306/*
1307 * A partial copy also needs to zero the uncopied region.
1308 */
1309static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
1310 struct dm_dev *origin, dm_block_t data_origin,
1311 dm_block_t data_dest,
1312 struct dm_bio_prison_cell *cell, struct bio *bio,
1313 sector_t len)
1314{
1315 struct pool *pool = tc->pool;
1316 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1317
1318 m->tc = tc;
1319 m->virt_begin = virt_block;
1320 m->virt_end = virt_block + 1u;
1321 m->data_block = data_dest;
1322 m->cell = cell;
1323
1324 /*
1325 * quiesce action + copy action + an extra reference held for the
1326 * duration of this function (we may need to inc later for a
1327 * partial zero).
1328 */
1329 atomic_set(&m->prepare_actions, 3);
1330
1331 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
1332 complete_mapping_preparation(m); /* already quiesced */
1333
1334 /*
1335 * IO to pool_dev remaps to the pool target's data_dev.
1336 *
1337 * If the whole block of data is being overwritten, we can issue the
1338 * bio immediately. Otherwise we use kcopyd to clone the data first.
1339 */
1340 if (io_overwrites_block(pool, bio))
1341 remap_and_issue_overwrite(tc, bio, data_dest, m);
1342 else {
1343 struct dm_io_region from, to;
1344
1345 from.bdev = origin->bdev;
1346 from.sector = data_origin * pool->sectors_per_block;
1347 from.count = len;
1348
1349 to.bdev = tc->pool_dev->bdev;
1350 to.sector = data_dest * pool->sectors_per_block;
1351 to.count = len;
1352
1353 dm_kcopyd_copy(pool->copier, &from, 1, &to,
1354 0, copy_complete, m);
1355
1356 /*
1357 * Do we need to zero a tail region?
1358 */
1359 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
1360 atomic_inc(&m->prepare_actions);
1361 ll_zero(tc, m,
1362 data_dest * pool->sectors_per_block + len,
1363 (data_dest + 1) * pool->sectors_per_block);
1364 }
1365 }
1366
1367 complete_mapping_preparation(m); /* drop our ref */
1368}
1369
1370static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
1371 dm_block_t data_origin, dm_block_t data_dest,
1372 struct dm_bio_prison_cell *cell, struct bio *bio)
1373{
1374 schedule_copy(tc, virt_block, tc->pool_dev,
1375 data_origin, data_dest, cell, bio,
1376 tc->pool->sectors_per_block);
1377}
1378
1379static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
1380 dm_block_t data_block, struct dm_bio_prison_cell *cell,
1381 struct bio *bio)
1382{
1383 struct pool *pool = tc->pool;
1384 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1385
1386 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
1387 m->tc = tc;
1388 m->virt_begin = virt_block;
1389 m->virt_end = virt_block + 1u;
1390 m->data_block = data_block;
1391 m->cell = cell;
1392
1393 /*
1394 * If the whole block of data is being overwritten or we are not
1395 * zeroing pre-existing data, we can issue the bio immediately.
1396 * Otherwise we use kcopyd to zero the data first.
1397 */
1398 if (pool->pf.zero_new_blocks) {
1399 if (io_overwrites_block(pool, bio))
1400 remap_and_issue_overwrite(tc, bio, data_block, m);
1401 else {
1402 ll_zero(tc, m, data_block * pool->sectors_per_block,
1403 (data_block + 1) * pool->sectors_per_block);
1404 }
1405 } else
1406 process_prepared_mapping(m);
1407}
1408
1409static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1410 dm_block_t data_dest,
1411 struct dm_bio_prison_cell *cell, struct bio *bio)
1412{
1413 struct pool *pool = tc->pool;
1414 sector_t virt_block_begin = virt_block * pool->sectors_per_block;
1415 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
1416
1417 if (virt_block_end <= tc->origin_size) {
1418 schedule_copy(tc, virt_block, tc->origin_dev,
1419 virt_block, data_dest, cell, bio,
1420 pool->sectors_per_block);
1421
1422 } else if (virt_block_begin < tc->origin_size) {
1423 schedule_copy(tc, virt_block, tc->origin_dev,
1424 virt_block, data_dest, cell, bio,
1425 tc->origin_size - virt_block_begin);
1426
1427 } else
1428 schedule_zero(tc, virt_block, data_dest, cell, bio);
1429}
1430
1431static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
1432
1433static void requeue_bios(struct pool *pool);
1434
1435static bool is_read_only_pool_mode(enum pool_mode mode)
1436{
1437 return (mode == PM_OUT_OF_METADATA_SPACE || mode == PM_READ_ONLY);
1438}
1439
1440static bool is_read_only(struct pool *pool)
1441{
1442 return is_read_only_pool_mode(get_pool_mode(pool));
1443}
1444
1445static void check_for_metadata_space(struct pool *pool)
1446{
1447 int r;
1448 const char *ooms_reason = NULL;
1449 dm_block_t nr_free;
1450
1451 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free);
1452 if (r)
1453 ooms_reason = "Could not get free metadata blocks";
1454 else if (!nr_free)
1455 ooms_reason = "No free metadata blocks";
1456
1457 if (ooms_reason && !is_read_only(pool)) {
1458 DMERR("%s", ooms_reason);
1459 set_pool_mode(pool, PM_OUT_OF_METADATA_SPACE);
1460 }
1461}
1462
1463static void check_for_data_space(struct pool *pool)
1464{
1465 int r;
1466 dm_block_t nr_free;
1467
1468 if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)
1469 return;
1470
1471 r = dm_pool_get_free_block_count(pool->pmd, &nr_free);
1472 if (r)
1473 return;
1474
1475 if (nr_free) {
1476 set_pool_mode(pool, PM_WRITE);
1477 requeue_bios(pool);
1478 }
1479}
1480
1481/*
1482 * A non-zero return indicates read_only or fail_io mode.
1483 * Many callers don't care about the return value.
1484 */
1485static int commit(struct pool *pool)
1486{
1487 int r;
1488
1489 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE)
1490 return -EINVAL;
1491
1492 r = dm_pool_commit_metadata(pool->pmd);
1493 if (r)
1494 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
1495 else {
1496 check_for_metadata_space(pool);
1497 check_for_data_space(pool);
1498 }
1499
1500 return r;
1501}
1502
1503static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
1504{
1505 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1506 DMWARN("%s: reached low water mark for data device: sending event.",
1507 dm_device_name(pool->pool_md));
1508 spin_lock_irq(&pool->lock);
1509 pool->low_water_triggered = true;
1510 spin_unlock_irq(&pool->lock);
1511 dm_table_event(pool->ti->table);
1512 }
1513}
1514
1515static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1516{
1517 int r;
1518 dm_block_t free_blocks;
1519 struct pool *pool = tc->pool;
1520
1521 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
1522 return -EINVAL;
1523
1524 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1525 if (r) {
1526 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1527 return r;
1528 }
1529
1530 check_low_water_mark(pool, free_blocks);
1531
1532 if (!free_blocks) {
1533 /*
1534 * Try to commit to see if that will free up some
1535 * more space.
1536 */
1537 r = commit(pool);
1538 if (r)
1539 return r;
1540
1541 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1542 if (r) {
1543 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1544 return r;
1545 }
1546
1547 if (!free_blocks) {
1548 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1549 return -ENOSPC;
1550 }
1551 }
1552
1553 r = dm_pool_alloc_data_block(pool->pmd, result);
1554 if (r) {
1555 if (r == -ENOSPC)
1556 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1557 else
1558 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1559 return r;
1560 }
1561
1562 r = dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks);
1563 if (r) {
1564 metadata_operation_failed(pool, "dm_pool_get_free_metadata_block_count", r);
1565 return r;
1566 }
1567
1568 if (!free_blocks) {
1569 /* Let's commit before we use up the metadata reserve. */
1570 r = commit(pool);
1571 if (r)
1572 return r;
1573 }
1574
1575 return 0;
1576}
1577
1578/*
1579 * If we have run out of space, queue bios until the device is
1580 * resumed, presumably after having been reloaded with more space.
1581 */
1582static void retry_on_resume(struct bio *bio)
1583{
1584 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1585 struct thin_c *tc = h->tc;
1586
1587 spin_lock_irq(&tc->lock);
1588 bio_list_add(&tc->retry_on_resume_list, bio);
1589 spin_unlock_irq(&tc->lock);
1590}
1591
1592static blk_status_t should_error_unserviceable_bio(struct pool *pool)
1593{
1594 enum pool_mode m = get_pool_mode(pool);
1595
1596 switch (m) {
1597 case PM_WRITE:
1598 /* Shouldn't get here */
1599 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1600 return BLK_STS_IOERR;
1601
1602 case PM_OUT_OF_DATA_SPACE:
1603 return pool->pf.error_if_no_space ? BLK_STS_NOSPC : 0;
1604
1605 case PM_OUT_OF_METADATA_SPACE:
1606 case PM_READ_ONLY:
1607 case PM_FAIL:
1608 return BLK_STS_IOERR;
1609 default:
1610 /* Shouldn't get here */
1611 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1612 return BLK_STS_IOERR;
1613 }
1614}
1615
1616static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1617{
1618 blk_status_t error = should_error_unserviceable_bio(pool);
1619
1620 if (error) {
1621 bio->bi_status = error;
1622 bio_endio(bio);
1623 } else
1624 retry_on_resume(bio);
1625}
1626
1627static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1628{
1629 struct bio *bio;
1630 struct bio_list bios;
1631 blk_status_t error;
1632
1633 error = should_error_unserviceable_bio(pool);
1634 if (error) {
1635 cell_error_with_code(pool, cell, error);
1636 return;
1637 }
1638
1639 bio_list_init(&bios);
1640 cell_release(pool, cell, &bios);
1641
1642 while ((bio = bio_list_pop(&bios)))
1643 retry_on_resume(bio);
1644}
1645
1646static void process_discard_cell_no_passdown(struct thin_c *tc,
1647 struct dm_bio_prison_cell *virt_cell)
1648{
1649 struct pool *pool = tc->pool;
1650 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1651
1652 /*
1653 * We don't need to lock the data blocks, since there's no
1654 * passdown. We only lock data blocks for allocation and breaking sharing.
1655 */
1656 m->tc = tc;
1657 m->virt_begin = virt_cell->key.block_begin;
1658 m->virt_end = virt_cell->key.block_end;
1659 m->cell = virt_cell;
1660 m->bio = virt_cell->holder;
1661
1662 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1663 pool->process_prepared_discard(m);
1664}
1665
1666static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end,
1667 struct bio *bio)
1668{
1669 struct pool *pool = tc->pool;
1670
1671 int r;
1672 bool maybe_shared;
1673 struct dm_cell_key data_key;
1674 struct dm_bio_prison_cell *data_cell;
1675 struct dm_thin_new_mapping *m;
1676 dm_block_t virt_begin, virt_end, data_begin, data_end;
1677 dm_block_t len, next_boundary;
1678
1679 while (begin != end) {
1680 r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end,
1681 &data_begin, &maybe_shared);
1682 if (r) {
1683 /*
1684 * Silently fail, letting any mappings we've
1685 * created complete.
1686 */
1687 break;
1688 }
1689
1690 data_end = data_begin + (virt_end - virt_begin);
1691
1692 /*
1693 * Make sure the data region obeys the bio prison restrictions.
1694 */
1695 while (data_begin < data_end) {
1696 r = ensure_next_mapping(pool);
1697 if (r)
1698 return; /* we did our best */
1699
1700 next_boundary = ((data_begin >> BIO_PRISON_MAX_RANGE_SHIFT) + 1)
1701 << BIO_PRISON_MAX_RANGE_SHIFT;
1702 len = min_t(sector_t, data_end - data_begin, next_boundary - data_begin);
1703
1704 /* This key is certainly within range given the above splitting */
1705 (void) build_key(tc->td, PHYSICAL, data_begin, data_begin + len, &data_key);
1706 if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) {
1707 /* contention, we'll give up with this range */
1708 data_begin += len;
1709 continue;
1710 }
1711
1712 /*
1713 * IO may still be going to the destination block. We must
1714 * quiesce before we can do the removal.
1715 */
1716 m = get_next_mapping(pool);
1717 m->tc = tc;
1718 m->maybe_shared = maybe_shared;
1719 m->virt_begin = virt_begin;
1720 m->virt_end = virt_begin + len;
1721 m->data_block = data_begin;
1722 m->cell = data_cell;
1723 m->bio = bio;
1724
1725 /*
1726 * The parent bio must not complete before sub discard bios are
1727 * chained to it (see end_discard's bio_chain)!
1728 *
1729 * This per-mapping bi_remaining increment is paired with
1730 * the implicit decrement that occurs via bio_endio() in
1731 * end_discard().
1732 */
1733 bio_inc_remaining(bio);
1734 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1735 pool->process_prepared_discard(m);
1736
1737 virt_begin += len;
1738 data_begin += len;
1739 }
1740
1741 begin = virt_end;
1742 }
1743}
1744
1745static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell)
1746{
1747 struct bio *bio = virt_cell->holder;
1748 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1749
1750 /*
1751 * The virt_cell will only get freed once the origin bio completes.
1752 * This means it will remain locked while all the individual
1753 * passdown bios are in flight.
1754 */
1755 h->cell = virt_cell;
1756 break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio);
1757
1758 /*
1759 * We complete the bio now, knowing that the bi_remaining field
1760 * will prevent completion until the sub range discards have
1761 * completed.
1762 */
1763 bio_endio(bio);
1764}
1765
1766static void process_discard_bio(struct thin_c *tc, struct bio *bio)
1767{
1768 dm_block_t begin, end;
1769 struct dm_cell_key virt_key;
1770 struct dm_bio_prison_cell *virt_cell;
1771
1772 get_bio_block_range(tc, bio, &begin, &end);
1773 if (begin == end) {
1774 /*
1775 * The discard covers less than a block.
1776 */
1777 bio_endio(bio);
1778 return;
1779 }
1780
1781 if (unlikely(!build_key(tc->td, VIRTUAL, begin, end, &virt_key))) {
1782 DMERR_LIMIT("Discard doesn't respect bio prison limits");
1783 bio_endio(bio);
1784 return;
1785 }
1786
1787 if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) {
1788 /*
1789 * Potential starvation issue: We're relying on the
1790 * fs/application being well behaved, and not trying to
1791 * send IO to a region at the same time as discarding it.
1792 * If they do this persistently then it's possible this
1793 * cell will never be granted.
1794 */
1795 return;
1796 }
1797
1798 tc->pool->process_discard_cell(tc, virt_cell);
1799}
1800
1801static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1802 struct dm_cell_key *key,
1803 struct dm_thin_lookup_result *lookup_result,
1804 struct dm_bio_prison_cell *cell)
1805{
1806 int r;
1807 dm_block_t data_block;
1808 struct pool *pool = tc->pool;
1809
1810 r = alloc_data_block(tc, &data_block);
1811 switch (r) {
1812 case 0:
1813 schedule_internal_copy(tc, block, lookup_result->block,
1814 data_block, cell, bio);
1815 break;
1816
1817 case -ENOSPC:
1818 retry_bios_on_resume(pool, cell);
1819 break;
1820
1821 default:
1822 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1823 __func__, r);
1824 cell_error(pool, cell);
1825 break;
1826 }
1827}
1828
1829static void __remap_and_issue_shared_cell(void *context,
1830 struct dm_bio_prison_cell *cell)
1831{
1832 struct remap_info *info = context;
1833 struct bio *bio;
1834
1835 while ((bio = bio_list_pop(&cell->bios))) {
1836 if (bio_data_dir(bio) == WRITE || op_is_flush(bio->bi_opf) ||
1837 bio_op(bio) == REQ_OP_DISCARD)
1838 bio_list_add(&info->defer_bios, bio);
1839 else {
1840 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1841
1842 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds);
1843 inc_all_io_entry(info->tc->pool, bio);
1844 bio_list_add(&info->issue_bios, bio);
1845 }
1846 }
1847}
1848
1849static void remap_and_issue_shared_cell(struct thin_c *tc,
1850 struct dm_bio_prison_cell *cell,
1851 dm_block_t block)
1852{
1853 struct bio *bio;
1854 struct remap_info info;
1855
1856 info.tc = tc;
1857 bio_list_init(&info.defer_bios);
1858 bio_list_init(&info.issue_bios);
1859
1860 cell_visit_release(tc->pool, __remap_and_issue_shared_cell,
1861 &info, cell);
1862
1863 while ((bio = bio_list_pop(&info.defer_bios)))
1864 thin_defer_bio(tc, bio);
1865
1866 while ((bio = bio_list_pop(&info.issue_bios)))
1867 remap_and_issue(tc, bio, block);
1868}
1869
1870static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1871 dm_block_t block,
1872 struct dm_thin_lookup_result *lookup_result,
1873 struct dm_bio_prison_cell *virt_cell)
1874{
1875 struct dm_bio_prison_cell *data_cell;
1876 struct pool *pool = tc->pool;
1877 struct dm_cell_key key;
1878
1879 /*
1880 * If cell is already occupied, then sharing is already in the process
1881 * of being broken so we have nothing further to do here.
1882 */
1883 build_data_key(tc->td, lookup_result->block, &key);
1884 if (bio_detain(pool, &key, bio, &data_cell)) {
1885 cell_defer_no_holder(tc, virt_cell);
1886 return;
1887 }
1888
1889 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) {
1890 break_sharing(tc, bio, block, &key, lookup_result, data_cell);
1891 cell_defer_no_holder(tc, virt_cell);
1892 } else {
1893 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1894
1895 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1896 inc_all_io_entry(pool, bio);
1897 remap_and_issue(tc, bio, lookup_result->block);
1898
1899 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block);
1900 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block);
1901 }
1902}
1903
1904static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1905 struct dm_bio_prison_cell *cell)
1906{
1907 int r;
1908 dm_block_t data_block;
1909 struct pool *pool = tc->pool;
1910
1911 /*
1912 * Remap empty bios (flushes) immediately, without provisioning.
1913 */
1914 if (!bio->bi_iter.bi_size) {
1915 inc_all_io_entry(pool, bio);
1916 cell_defer_no_holder(tc, cell);
1917
1918 remap_and_issue(tc, bio, 0);
1919 return;
1920 }
1921
1922 /*
1923 * Fill read bios with zeroes and complete them immediately.
1924 */
1925 if (bio_data_dir(bio) == READ) {
1926 zero_fill_bio(bio);
1927 cell_defer_no_holder(tc, cell);
1928 bio_endio(bio);
1929 return;
1930 }
1931
1932 r = alloc_data_block(tc, &data_block);
1933 switch (r) {
1934 case 0:
1935 if (tc->origin_dev)
1936 schedule_external_copy(tc, block, data_block, cell, bio);
1937 else
1938 schedule_zero(tc, block, data_block, cell, bio);
1939 break;
1940
1941 case -ENOSPC:
1942 retry_bios_on_resume(pool, cell);
1943 break;
1944
1945 default:
1946 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1947 __func__, r);
1948 cell_error(pool, cell);
1949 break;
1950 }
1951}
1952
1953static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1954{
1955 int r;
1956 struct pool *pool = tc->pool;
1957 struct bio *bio = cell->holder;
1958 dm_block_t block = get_bio_block(tc, bio);
1959 struct dm_thin_lookup_result lookup_result;
1960
1961 if (tc->requeue_mode) {
1962 cell_requeue(pool, cell);
1963 return;
1964 }
1965
1966 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1967 switch (r) {
1968 case 0:
1969 if (lookup_result.shared)
1970 process_shared_bio(tc, bio, block, &lookup_result, cell);
1971 else {
1972 inc_all_io_entry(pool, bio);
1973 remap_and_issue(tc, bio, lookup_result.block);
1974 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1975 }
1976 break;
1977
1978 case -ENODATA:
1979 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1980 inc_all_io_entry(pool, bio);
1981 cell_defer_no_holder(tc, cell);
1982
1983 if (bio_end_sector(bio) <= tc->origin_size)
1984 remap_to_origin_and_issue(tc, bio);
1985
1986 else if (bio->bi_iter.bi_sector < tc->origin_size) {
1987 zero_fill_bio(bio);
1988 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
1989 remap_to_origin_and_issue(tc, bio);
1990
1991 } else {
1992 zero_fill_bio(bio);
1993 bio_endio(bio);
1994 }
1995 } else
1996 provision_block(tc, bio, block, cell);
1997 break;
1998
1999 default:
2000 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
2001 __func__, r);
2002 cell_defer_no_holder(tc, cell);
2003 bio_io_error(bio);
2004 break;
2005 }
2006}
2007
2008static void process_bio(struct thin_c *tc, struct bio *bio)
2009{
2010 struct pool *pool = tc->pool;
2011 dm_block_t block = get_bio_block(tc, bio);
2012 struct dm_bio_prison_cell *cell;
2013 struct dm_cell_key key;
2014
2015 /*
2016 * If cell is already occupied, then the block is already
2017 * being provisioned so we have nothing further to do here.
2018 */
2019 build_virtual_key(tc->td, block, &key);
2020 if (bio_detain(pool, &key, bio, &cell))
2021 return;
2022
2023 process_cell(tc, cell);
2024}
2025
2026static void __process_bio_read_only(struct thin_c *tc, struct bio *bio,
2027 struct dm_bio_prison_cell *cell)
2028{
2029 int r;
2030 int rw = bio_data_dir(bio);
2031 dm_block_t block = get_bio_block(tc, bio);
2032 struct dm_thin_lookup_result lookup_result;
2033
2034 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
2035 switch (r) {
2036 case 0:
2037 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) {
2038 handle_unserviceable_bio(tc->pool, bio);
2039 if (cell)
2040 cell_defer_no_holder(tc, cell);
2041 } else {
2042 inc_all_io_entry(tc->pool, bio);
2043 remap_and_issue(tc, bio, lookup_result.block);
2044 if (cell)
2045 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
2046 }
2047 break;
2048
2049 case -ENODATA:
2050 if (cell)
2051 cell_defer_no_holder(tc, cell);
2052 if (rw != READ) {
2053 handle_unserviceable_bio(tc->pool, bio);
2054 break;
2055 }
2056
2057 if (tc->origin_dev) {
2058 inc_all_io_entry(tc->pool, bio);
2059 remap_to_origin_and_issue(tc, bio);
2060 break;
2061 }
2062
2063 zero_fill_bio(bio);
2064 bio_endio(bio);
2065 break;
2066
2067 default:
2068 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
2069 __func__, r);
2070 if (cell)
2071 cell_defer_no_holder(tc, cell);
2072 bio_io_error(bio);
2073 break;
2074 }
2075}
2076
2077static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
2078{
2079 __process_bio_read_only(tc, bio, NULL);
2080}
2081
2082static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2083{
2084 __process_bio_read_only(tc, cell->holder, cell);
2085}
2086
2087static void process_bio_success(struct thin_c *tc, struct bio *bio)
2088{
2089 bio_endio(bio);
2090}
2091
2092static void process_bio_fail(struct thin_c *tc, struct bio *bio)
2093{
2094 bio_io_error(bio);
2095}
2096
2097static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2098{
2099 cell_success(tc->pool, cell);
2100}
2101
2102static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2103{
2104 cell_error(tc->pool, cell);
2105}
2106
2107/*
2108 * FIXME: should we also commit due to size of transaction, measured in
2109 * metadata blocks?
2110 */
2111static int need_commit_due_to_time(struct pool *pool)
2112{
2113 return !time_in_range(jiffies, pool->last_commit_jiffies,
2114 pool->last_commit_jiffies + COMMIT_PERIOD);
2115}
2116
2117#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
2118#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
2119
2120static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
2121{
2122 struct rb_node **rbp, *parent;
2123 struct dm_thin_endio_hook *pbd;
2124 sector_t bi_sector = bio->bi_iter.bi_sector;
2125
2126 rbp = &tc->sort_bio_list.rb_node;
2127 parent = NULL;
2128 while (*rbp) {
2129 parent = *rbp;
2130 pbd = thin_pbd(parent);
2131
2132 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
2133 rbp = &(*rbp)->rb_left;
2134 else
2135 rbp = &(*rbp)->rb_right;
2136 }
2137
2138 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2139 rb_link_node(&pbd->rb_node, parent, rbp);
2140 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
2141}
2142
2143static void __extract_sorted_bios(struct thin_c *tc)
2144{
2145 struct rb_node *node;
2146 struct dm_thin_endio_hook *pbd;
2147 struct bio *bio;
2148
2149 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
2150 pbd = thin_pbd(node);
2151 bio = thin_bio(pbd);
2152
2153 bio_list_add(&tc->deferred_bio_list, bio);
2154 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
2155 }
2156
2157 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
2158}
2159
2160static void __sort_thin_deferred_bios(struct thin_c *tc)
2161{
2162 struct bio *bio;
2163 struct bio_list bios;
2164
2165 bio_list_init(&bios);
2166 bio_list_merge(&bios, &tc->deferred_bio_list);
2167 bio_list_init(&tc->deferred_bio_list);
2168
2169 /* Sort deferred_bio_list using rb-tree */
2170 while ((bio = bio_list_pop(&bios)))
2171 __thin_bio_rb_add(tc, bio);
2172
2173 /*
2174 * Transfer the sorted bios in sort_bio_list back to
2175 * deferred_bio_list to allow lockless submission of
2176 * all bios.
2177 */
2178 __extract_sorted_bios(tc);
2179}
2180
2181static void process_thin_deferred_bios(struct thin_c *tc)
2182{
2183 struct pool *pool = tc->pool;
2184 struct bio *bio;
2185 struct bio_list bios;
2186 struct blk_plug plug;
2187 unsigned int count = 0;
2188
2189 if (tc->requeue_mode) {
2190 error_thin_bio_list(tc, &tc->deferred_bio_list,
2191 BLK_STS_DM_REQUEUE);
2192 return;
2193 }
2194
2195 bio_list_init(&bios);
2196
2197 spin_lock_irq(&tc->lock);
2198
2199 if (bio_list_empty(&tc->deferred_bio_list)) {
2200 spin_unlock_irq(&tc->lock);
2201 return;
2202 }
2203
2204 __sort_thin_deferred_bios(tc);
2205
2206 bio_list_merge(&bios, &tc->deferred_bio_list);
2207 bio_list_init(&tc->deferred_bio_list);
2208
2209 spin_unlock_irq(&tc->lock);
2210
2211 blk_start_plug(&plug);
2212 while ((bio = bio_list_pop(&bios))) {
2213 /*
2214 * If we've got no free new_mapping structs, and processing
2215 * this bio might require one, we pause until there are some
2216 * prepared mappings to process.
2217 */
2218 if (ensure_next_mapping(pool)) {
2219 spin_lock_irq(&tc->lock);
2220 bio_list_add(&tc->deferred_bio_list, bio);
2221 bio_list_merge(&tc->deferred_bio_list, &bios);
2222 spin_unlock_irq(&tc->lock);
2223 break;
2224 }
2225
2226 if (bio_op(bio) == REQ_OP_DISCARD)
2227 pool->process_discard(tc, bio);
2228 else
2229 pool->process_bio(tc, bio);
2230
2231 if ((count++ & 127) == 0) {
2232 throttle_work_update(&pool->throttle);
2233 dm_pool_issue_prefetches(pool->pmd);
2234 }
2235 cond_resched();
2236 }
2237 blk_finish_plug(&plug);
2238}
2239
2240static int cmp_cells(const void *lhs, const void *rhs)
2241{
2242 struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs);
2243 struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs);
2244
2245 BUG_ON(!lhs_cell->holder);
2246 BUG_ON(!rhs_cell->holder);
2247
2248 if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector)
2249 return -1;
2250
2251 if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector)
2252 return 1;
2253
2254 return 0;
2255}
2256
2257static unsigned int sort_cells(struct pool *pool, struct list_head *cells)
2258{
2259 unsigned int count = 0;
2260 struct dm_bio_prison_cell *cell, *tmp;
2261
2262 list_for_each_entry_safe(cell, tmp, cells, user_list) {
2263 if (count >= CELL_SORT_ARRAY_SIZE)
2264 break;
2265
2266 pool->cell_sort_array[count++] = cell;
2267 list_del(&cell->user_list);
2268 }
2269
2270 sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL);
2271
2272 return count;
2273}
2274
2275static void process_thin_deferred_cells(struct thin_c *tc)
2276{
2277 struct pool *pool = tc->pool;
2278 struct list_head cells;
2279 struct dm_bio_prison_cell *cell;
2280 unsigned int i, j, count;
2281
2282 INIT_LIST_HEAD(&cells);
2283
2284 spin_lock_irq(&tc->lock);
2285 list_splice_init(&tc->deferred_cells, &cells);
2286 spin_unlock_irq(&tc->lock);
2287
2288 if (list_empty(&cells))
2289 return;
2290
2291 do {
2292 count = sort_cells(tc->pool, &cells);
2293
2294 for (i = 0; i < count; i++) {
2295 cell = pool->cell_sort_array[i];
2296 BUG_ON(!cell->holder);
2297
2298 /*
2299 * If we've got no free new_mapping structs, and processing
2300 * this bio might require one, we pause until there are some
2301 * prepared mappings to process.
2302 */
2303 if (ensure_next_mapping(pool)) {
2304 for (j = i; j < count; j++)
2305 list_add(&pool->cell_sort_array[j]->user_list, &cells);
2306
2307 spin_lock_irq(&tc->lock);
2308 list_splice(&cells, &tc->deferred_cells);
2309 spin_unlock_irq(&tc->lock);
2310 return;
2311 }
2312
2313 if (bio_op(cell->holder) == REQ_OP_DISCARD)
2314 pool->process_discard_cell(tc, cell);
2315 else
2316 pool->process_cell(tc, cell);
2317 }
2318 cond_resched();
2319 } while (!list_empty(&cells));
2320}
2321
2322static void thin_get(struct thin_c *tc);
2323static void thin_put(struct thin_c *tc);
2324
2325/*
2326 * We can't hold rcu_read_lock() around code that can block. So we
2327 * find a thin with the rcu lock held; bump a refcount; then drop
2328 * the lock.
2329 */
2330static struct thin_c *get_first_thin(struct pool *pool)
2331{
2332 struct thin_c *tc = NULL;
2333
2334 rcu_read_lock();
2335 tc = list_first_or_null_rcu(&pool->active_thins, struct thin_c, list);
2336 if (tc)
2337 thin_get(tc);
2338 rcu_read_unlock();
2339
2340 return tc;
2341}
2342
2343static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
2344{
2345 struct thin_c *old_tc = tc;
2346
2347 rcu_read_lock();
2348 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
2349 thin_get(tc);
2350 thin_put(old_tc);
2351 rcu_read_unlock();
2352 return tc;
2353 }
2354 thin_put(old_tc);
2355 rcu_read_unlock();
2356
2357 return NULL;
2358}
2359
2360static void process_deferred_bios(struct pool *pool)
2361{
2362 struct bio *bio;
2363 struct bio_list bios, bio_completions;
2364 struct thin_c *tc;
2365
2366 tc = get_first_thin(pool);
2367 while (tc) {
2368 process_thin_deferred_cells(tc);
2369 process_thin_deferred_bios(tc);
2370 tc = get_next_thin(pool, tc);
2371 }
2372
2373 /*
2374 * If there are any deferred flush bios, we must commit the metadata
2375 * before issuing them or signaling their completion.
2376 */
2377 bio_list_init(&bios);
2378 bio_list_init(&bio_completions);
2379
2380 spin_lock_irq(&pool->lock);
2381 bio_list_merge(&bios, &pool->deferred_flush_bios);
2382 bio_list_init(&pool->deferred_flush_bios);
2383
2384 bio_list_merge(&bio_completions, &pool->deferred_flush_completions);
2385 bio_list_init(&pool->deferred_flush_completions);
2386 spin_unlock_irq(&pool->lock);
2387
2388 if (bio_list_empty(&bios) && bio_list_empty(&bio_completions) &&
2389 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
2390 return;
2391
2392 if (commit(pool)) {
2393 bio_list_merge(&bios, &bio_completions);
2394
2395 while ((bio = bio_list_pop(&bios)))
2396 bio_io_error(bio);
2397 return;
2398 }
2399 pool->last_commit_jiffies = jiffies;
2400
2401 while ((bio = bio_list_pop(&bio_completions)))
2402 bio_endio(bio);
2403
2404 while ((bio = bio_list_pop(&bios))) {
2405 /*
2406 * The data device was flushed as part of metadata commit,
2407 * so complete redundant flushes immediately.
2408 */
2409 if (bio->bi_opf & REQ_PREFLUSH)
2410 bio_endio(bio);
2411 else
2412 dm_submit_bio_remap(bio, NULL);
2413 }
2414}
2415
2416static void do_worker(struct work_struct *ws)
2417{
2418 struct pool *pool = container_of(ws, struct pool, worker);
2419
2420 throttle_work_start(&pool->throttle);
2421 dm_pool_issue_prefetches(pool->pmd);
2422 throttle_work_update(&pool->throttle);
2423 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
2424 throttle_work_update(&pool->throttle);
2425 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
2426 throttle_work_update(&pool->throttle);
2427 process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2);
2428 throttle_work_update(&pool->throttle);
2429 process_deferred_bios(pool);
2430 throttle_work_complete(&pool->throttle);
2431}
2432
2433/*
2434 * We want to commit periodically so that not too much
2435 * unwritten data builds up.
2436 */
2437static void do_waker(struct work_struct *ws)
2438{
2439 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
2440
2441 wake_worker(pool);
2442 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
2443}
2444
2445/*
2446 * We're holding onto IO to allow userland time to react. After the
2447 * timeout either the pool will have been resized (and thus back in
2448 * PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space.
2449 */
2450static void do_no_space_timeout(struct work_struct *ws)
2451{
2452 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
2453 no_space_timeout);
2454
2455 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) {
2456 pool->pf.error_if_no_space = true;
2457 notify_of_pool_mode_change(pool);
2458 error_retry_list_with_code(pool, BLK_STS_NOSPC);
2459 }
2460}
2461
2462/*----------------------------------------------------------------*/
2463
2464struct pool_work {
2465 struct work_struct worker;
2466 struct completion complete;
2467};
2468
2469static struct pool_work *to_pool_work(struct work_struct *ws)
2470{
2471 return container_of(ws, struct pool_work, worker);
2472}
2473
2474static void pool_work_complete(struct pool_work *pw)
2475{
2476 complete(&pw->complete);
2477}
2478
2479static void pool_work_wait(struct pool_work *pw, struct pool *pool,
2480 void (*fn)(struct work_struct *))
2481{
2482 INIT_WORK_ONSTACK(&pw->worker, fn);
2483 init_completion(&pw->complete);
2484 queue_work(pool->wq, &pw->worker);
2485 wait_for_completion(&pw->complete);
2486 destroy_work_on_stack(&pw->worker);
2487}
2488
2489/*----------------------------------------------------------------*/
2490
2491struct noflush_work {
2492 struct pool_work pw;
2493 struct thin_c *tc;
2494};
2495
2496static struct noflush_work *to_noflush(struct work_struct *ws)
2497{
2498 return container_of(to_pool_work(ws), struct noflush_work, pw);
2499}
2500
2501static void do_noflush_start(struct work_struct *ws)
2502{
2503 struct noflush_work *w = to_noflush(ws);
2504
2505 w->tc->requeue_mode = true;
2506 requeue_io(w->tc);
2507 pool_work_complete(&w->pw);
2508}
2509
2510static void do_noflush_stop(struct work_struct *ws)
2511{
2512 struct noflush_work *w = to_noflush(ws);
2513
2514 w->tc->requeue_mode = false;
2515 pool_work_complete(&w->pw);
2516}
2517
2518static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
2519{
2520 struct noflush_work w;
2521
2522 w.tc = tc;
2523 pool_work_wait(&w.pw, tc->pool, fn);
2524}
2525
2526/*----------------------------------------------------------------*/
2527
2528static void set_discard_callbacks(struct pool *pool)
2529{
2530 struct pool_c *pt = pool->ti->private;
2531
2532 if (pt->adjusted_pf.discard_passdown) {
2533 pool->process_discard_cell = process_discard_cell_passdown;
2534 pool->process_prepared_discard = process_prepared_discard_passdown_pt1;
2535 pool->process_prepared_discard_pt2 = process_prepared_discard_passdown_pt2;
2536 } else {
2537 pool->process_discard_cell = process_discard_cell_no_passdown;
2538 pool->process_prepared_discard = process_prepared_discard_no_passdown;
2539 }
2540}
2541
2542static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
2543{
2544 struct pool_c *pt = pool->ti->private;
2545 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
2546 enum pool_mode old_mode = get_pool_mode(pool);
2547 unsigned long no_space_timeout = READ_ONCE(no_space_timeout_secs) * HZ;
2548
2549 /*
2550 * Never allow the pool to transition to PM_WRITE mode if user
2551 * intervention is required to verify metadata and data consistency.
2552 */
2553 if (new_mode == PM_WRITE && needs_check) {
2554 DMERR("%s: unable to switch pool to write mode until repaired.",
2555 dm_device_name(pool->pool_md));
2556 if (old_mode != new_mode)
2557 new_mode = old_mode;
2558 else
2559 new_mode = PM_READ_ONLY;
2560 }
2561 /*
2562 * If we were in PM_FAIL mode, rollback of metadata failed. We're
2563 * not going to recover without a thin_repair. So we never let the
2564 * pool move out of the old mode.
2565 */
2566 if (old_mode == PM_FAIL)
2567 new_mode = old_mode;
2568
2569 switch (new_mode) {
2570 case PM_FAIL:
2571 dm_pool_metadata_read_only(pool->pmd);
2572 pool->process_bio = process_bio_fail;
2573 pool->process_discard = process_bio_fail;
2574 pool->process_cell = process_cell_fail;
2575 pool->process_discard_cell = process_cell_fail;
2576 pool->process_prepared_mapping = process_prepared_mapping_fail;
2577 pool->process_prepared_discard = process_prepared_discard_fail;
2578
2579 error_retry_list(pool);
2580 break;
2581
2582 case PM_OUT_OF_METADATA_SPACE:
2583 case PM_READ_ONLY:
2584 dm_pool_metadata_read_only(pool->pmd);
2585 pool->process_bio = process_bio_read_only;
2586 pool->process_discard = process_bio_success;
2587 pool->process_cell = process_cell_read_only;
2588 pool->process_discard_cell = process_cell_success;
2589 pool->process_prepared_mapping = process_prepared_mapping_fail;
2590 pool->process_prepared_discard = process_prepared_discard_success;
2591
2592 error_retry_list(pool);
2593 break;
2594
2595 case PM_OUT_OF_DATA_SPACE:
2596 /*
2597 * Ideally we'd never hit this state; the low water mark
2598 * would trigger userland to extend the pool before we
2599 * completely run out of data space. However, many small
2600 * IOs to unprovisioned space can consume data space at an
2601 * alarming rate. Adjust your low water mark if you're
2602 * frequently seeing this mode.
2603 */
2604 pool->out_of_data_space = true;
2605 pool->process_bio = process_bio_read_only;
2606 pool->process_discard = process_discard_bio;
2607 pool->process_cell = process_cell_read_only;
2608 pool->process_prepared_mapping = process_prepared_mapping;
2609 set_discard_callbacks(pool);
2610
2611 if (!pool->pf.error_if_no_space && no_space_timeout)
2612 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
2613 break;
2614
2615 case PM_WRITE:
2616 if (old_mode == PM_OUT_OF_DATA_SPACE)
2617 cancel_delayed_work_sync(&pool->no_space_timeout);
2618 pool->out_of_data_space = false;
2619 pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space;
2620 dm_pool_metadata_read_write(pool->pmd);
2621 pool->process_bio = process_bio;
2622 pool->process_discard = process_discard_bio;
2623 pool->process_cell = process_cell;
2624 pool->process_prepared_mapping = process_prepared_mapping;
2625 set_discard_callbacks(pool);
2626 break;
2627 }
2628
2629 pool->pf.mode = new_mode;
2630 /*
2631 * The pool mode may have changed, sync it so bind_control_target()
2632 * doesn't cause an unexpected mode transition on resume.
2633 */
2634 pt->adjusted_pf.mode = new_mode;
2635
2636 if (old_mode != new_mode)
2637 notify_of_pool_mode_change(pool);
2638}
2639
2640static void abort_transaction(struct pool *pool)
2641{
2642 const char *dev_name = dm_device_name(pool->pool_md);
2643
2644 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
2645 if (dm_pool_abort_metadata(pool->pmd)) {
2646 DMERR("%s: failed to abort metadata transaction", dev_name);
2647 set_pool_mode(pool, PM_FAIL);
2648 }
2649
2650 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
2651 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
2652 set_pool_mode(pool, PM_FAIL);
2653 }
2654}
2655
2656static void metadata_operation_failed(struct pool *pool, const char *op, int r)
2657{
2658 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
2659 dm_device_name(pool->pool_md), op, r);
2660
2661 abort_transaction(pool);
2662 set_pool_mode(pool, PM_READ_ONLY);
2663}
2664
2665/*----------------------------------------------------------------*/
2666
2667/*
2668 * Mapping functions.
2669 */
2670
2671/*
2672 * Called only while mapping a thin bio to hand it over to the workqueue.
2673 */
2674static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
2675{
2676 struct pool *pool = tc->pool;
2677
2678 spin_lock_irq(&tc->lock);
2679 bio_list_add(&tc->deferred_bio_list, bio);
2680 spin_unlock_irq(&tc->lock);
2681
2682 wake_worker(pool);
2683}
2684
2685static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
2686{
2687 struct pool *pool = tc->pool;
2688
2689 throttle_lock(&pool->throttle);
2690 thin_defer_bio(tc, bio);
2691 throttle_unlock(&pool->throttle);
2692}
2693
2694static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2695{
2696 struct pool *pool = tc->pool;
2697
2698 throttle_lock(&pool->throttle);
2699 spin_lock_irq(&tc->lock);
2700 list_add_tail(&cell->user_list, &tc->deferred_cells);
2701 spin_unlock_irq(&tc->lock);
2702 throttle_unlock(&pool->throttle);
2703
2704 wake_worker(pool);
2705}
2706
2707static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
2708{
2709 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2710
2711 h->tc = tc;
2712 h->shared_read_entry = NULL;
2713 h->all_io_entry = NULL;
2714 h->overwrite_mapping = NULL;
2715 h->cell = NULL;
2716}
2717
2718/*
2719 * Non-blocking function called from the thin target's map function.
2720 */
2721static int thin_bio_map(struct dm_target *ti, struct bio *bio)
2722{
2723 int r;
2724 struct thin_c *tc = ti->private;
2725 dm_block_t block = get_bio_block(tc, bio);
2726 struct dm_thin_device *td = tc->td;
2727 struct dm_thin_lookup_result result;
2728 struct dm_bio_prison_cell *virt_cell, *data_cell;
2729 struct dm_cell_key key;
2730
2731 thin_hook_bio(tc, bio);
2732
2733 if (tc->requeue_mode) {
2734 bio->bi_status = BLK_STS_DM_REQUEUE;
2735 bio_endio(bio);
2736 return DM_MAPIO_SUBMITTED;
2737 }
2738
2739 if (get_pool_mode(tc->pool) == PM_FAIL) {
2740 bio_io_error(bio);
2741 return DM_MAPIO_SUBMITTED;
2742 }
2743
2744 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) {
2745 thin_defer_bio_with_throttle(tc, bio);
2746 return DM_MAPIO_SUBMITTED;
2747 }
2748
2749 /*
2750 * We must hold the virtual cell before doing the lookup, otherwise
2751 * there's a race with discard.
2752 */
2753 build_virtual_key(tc->td, block, &key);
2754 if (bio_detain(tc->pool, &key, bio, &virt_cell))
2755 return DM_MAPIO_SUBMITTED;
2756
2757 r = dm_thin_find_block(td, block, 0, &result);
2758
2759 /*
2760 * Note that we defer readahead too.
2761 */
2762 switch (r) {
2763 case 0:
2764 if (unlikely(result.shared)) {
2765 /*
2766 * We have a race condition here between the
2767 * result.shared value returned by the lookup and
2768 * snapshot creation, which may cause new
2769 * sharing.
2770 *
2771 * To avoid this always quiesce the origin before
2772 * taking the snap. You want to do this anyway to
2773 * ensure a consistent application view
2774 * (i.e. lockfs).
2775 *
2776 * More distant ancestors are irrelevant. The
2777 * shared flag will be set in their case.
2778 */
2779 thin_defer_cell(tc, virt_cell);
2780 return DM_MAPIO_SUBMITTED;
2781 }
2782
2783 build_data_key(tc->td, result.block, &key);
2784 if (bio_detain(tc->pool, &key, bio, &data_cell)) {
2785 cell_defer_no_holder(tc, virt_cell);
2786 return DM_MAPIO_SUBMITTED;
2787 }
2788
2789 inc_all_io_entry(tc->pool, bio);
2790 cell_defer_no_holder(tc, data_cell);
2791 cell_defer_no_holder(tc, virt_cell);
2792
2793 remap(tc, bio, result.block);
2794 return DM_MAPIO_REMAPPED;
2795
2796 case -ENODATA:
2797 case -EWOULDBLOCK:
2798 thin_defer_cell(tc, virt_cell);
2799 return DM_MAPIO_SUBMITTED;
2800
2801 default:
2802 /*
2803 * Must always call bio_io_error on failure.
2804 * dm_thin_find_block can fail with -EINVAL if the
2805 * pool is switched to fail-io mode.
2806 */
2807 bio_io_error(bio);
2808 cell_defer_no_holder(tc, virt_cell);
2809 return DM_MAPIO_SUBMITTED;
2810 }
2811}
2812
2813static void requeue_bios(struct pool *pool)
2814{
2815 struct thin_c *tc;
2816
2817 rcu_read_lock();
2818 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
2819 spin_lock_irq(&tc->lock);
2820 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
2821 bio_list_init(&tc->retry_on_resume_list);
2822 spin_unlock_irq(&tc->lock);
2823 }
2824 rcu_read_unlock();
2825}
2826
2827/*
2828 *--------------------------------------------------------------
2829 * Binding of control targets to a pool object
2830 *--------------------------------------------------------------
2831 */
2832static bool is_factor(sector_t block_size, uint32_t n)
2833{
2834 return !sector_div(block_size, n);
2835}
2836
2837/*
2838 * If discard_passdown was enabled verify that the data device
2839 * supports discards. Disable discard_passdown if not.
2840 */
2841static void disable_discard_passdown_if_not_supported(struct pool_c *pt)
2842{
2843 struct pool *pool = pt->pool;
2844 struct block_device *data_bdev = pt->data_dev->bdev;
2845 struct queue_limits *data_limits = bdev_limits(data_bdev);
2846 const char *reason = NULL;
2847
2848 if (!pt->adjusted_pf.discard_passdown)
2849 return;
2850
2851 if (!bdev_max_discard_sectors(pt->data_dev->bdev))
2852 reason = "discard unsupported";
2853
2854 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
2855 reason = "max discard sectors smaller than a block";
2856
2857 if (reason) {
2858 DMWARN("Data device (%pg) %s: Disabling discard passdown.", data_bdev, reason);
2859 pt->adjusted_pf.discard_passdown = false;
2860 }
2861}
2862
2863static int bind_control_target(struct pool *pool, struct dm_target *ti)
2864{
2865 struct pool_c *pt = ti->private;
2866
2867 /*
2868 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2869 */
2870 enum pool_mode old_mode = get_pool_mode(pool);
2871 enum pool_mode new_mode = pt->adjusted_pf.mode;
2872
2873 /*
2874 * Don't change the pool's mode until set_pool_mode() below.
2875 * Otherwise the pool's process_* function pointers may
2876 * not match the desired pool mode.
2877 */
2878 pt->adjusted_pf.mode = old_mode;
2879
2880 pool->ti = ti;
2881 pool->pf = pt->adjusted_pf;
2882 pool->low_water_blocks = pt->low_water_blocks;
2883
2884 set_pool_mode(pool, new_mode);
2885
2886 return 0;
2887}
2888
2889static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2890{
2891 if (pool->ti == ti)
2892 pool->ti = NULL;
2893}
2894
2895/*
2896 *--------------------------------------------------------------
2897 * Pool creation
2898 *--------------------------------------------------------------
2899 */
2900/* Initialize pool features. */
2901static void pool_features_init(struct pool_features *pf)
2902{
2903 pf->mode = PM_WRITE;
2904 pf->zero_new_blocks = true;
2905 pf->discard_enabled = true;
2906 pf->discard_passdown = true;
2907 pf->error_if_no_space = false;
2908}
2909
2910static void __pool_destroy(struct pool *pool)
2911{
2912 __pool_table_remove(pool);
2913
2914 vfree(pool->cell_sort_array);
2915 if (dm_pool_metadata_close(pool->pmd) < 0)
2916 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2917
2918 dm_bio_prison_destroy(pool->prison);
2919 dm_kcopyd_client_destroy(pool->copier);
2920
2921 cancel_delayed_work_sync(&pool->waker);
2922 cancel_delayed_work_sync(&pool->no_space_timeout);
2923 if (pool->wq)
2924 destroy_workqueue(pool->wq);
2925
2926 if (pool->next_mapping)
2927 mempool_free(pool->next_mapping, &pool->mapping_pool);
2928 mempool_exit(&pool->mapping_pool);
2929 dm_deferred_set_destroy(pool->shared_read_ds);
2930 dm_deferred_set_destroy(pool->all_io_ds);
2931 kfree(pool);
2932}
2933
2934static struct kmem_cache *_new_mapping_cache;
2935
2936static struct pool *pool_create(struct mapped_device *pool_md,
2937 struct block_device *metadata_dev,
2938 struct block_device *data_dev,
2939 unsigned long block_size,
2940 int read_only, char **error)
2941{
2942 int r;
2943 void *err_p;
2944 struct pool *pool;
2945 struct dm_pool_metadata *pmd;
2946 bool format_device = read_only ? false : true;
2947
2948 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2949 if (IS_ERR(pmd)) {
2950 *error = "Error creating metadata object";
2951 return ERR_CAST(pmd);
2952 }
2953
2954 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
2955 if (!pool) {
2956 *error = "Error allocating memory for pool";
2957 err_p = ERR_PTR(-ENOMEM);
2958 goto bad_pool;
2959 }
2960
2961 pool->pmd = pmd;
2962 pool->sectors_per_block = block_size;
2963 if (block_size & (block_size - 1))
2964 pool->sectors_per_block_shift = -1;
2965 else
2966 pool->sectors_per_block_shift = __ffs(block_size);
2967 pool->low_water_blocks = 0;
2968 pool_features_init(&pool->pf);
2969 pool->prison = dm_bio_prison_create();
2970 if (!pool->prison) {
2971 *error = "Error creating pool's bio prison";
2972 err_p = ERR_PTR(-ENOMEM);
2973 goto bad_prison;
2974 }
2975
2976 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2977 if (IS_ERR(pool->copier)) {
2978 r = PTR_ERR(pool->copier);
2979 *error = "Error creating pool's kcopyd client";
2980 err_p = ERR_PTR(r);
2981 goto bad_kcopyd_client;
2982 }
2983
2984 /*
2985 * Create singlethreaded workqueue that will service all devices
2986 * that use this metadata.
2987 */
2988 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2989 if (!pool->wq) {
2990 *error = "Error creating pool's workqueue";
2991 err_p = ERR_PTR(-ENOMEM);
2992 goto bad_wq;
2993 }
2994
2995 throttle_init(&pool->throttle);
2996 INIT_WORK(&pool->worker, do_worker);
2997 INIT_DELAYED_WORK(&pool->waker, do_waker);
2998 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
2999 spin_lock_init(&pool->lock);
3000 bio_list_init(&pool->deferred_flush_bios);
3001 bio_list_init(&pool->deferred_flush_completions);
3002 INIT_LIST_HEAD(&pool->prepared_mappings);
3003 INIT_LIST_HEAD(&pool->prepared_discards);
3004 INIT_LIST_HEAD(&pool->prepared_discards_pt2);
3005 INIT_LIST_HEAD(&pool->active_thins);
3006 pool->low_water_triggered = false;
3007 pool->suspended = true;
3008 pool->out_of_data_space = false;
3009
3010 pool->shared_read_ds = dm_deferred_set_create();
3011 if (!pool->shared_read_ds) {
3012 *error = "Error creating pool's shared read deferred set";
3013 err_p = ERR_PTR(-ENOMEM);
3014 goto bad_shared_read_ds;
3015 }
3016
3017 pool->all_io_ds = dm_deferred_set_create();
3018 if (!pool->all_io_ds) {
3019 *error = "Error creating pool's all io deferred set";
3020 err_p = ERR_PTR(-ENOMEM);
3021 goto bad_all_io_ds;
3022 }
3023
3024 pool->next_mapping = NULL;
3025 r = mempool_init_slab_pool(&pool->mapping_pool, MAPPING_POOL_SIZE,
3026 _new_mapping_cache);
3027 if (r) {
3028 *error = "Error creating pool's mapping mempool";
3029 err_p = ERR_PTR(r);
3030 goto bad_mapping_pool;
3031 }
3032
3033 pool->cell_sort_array =
3034 vmalloc(array_size(CELL_SORT_ARRAY_SIZE,
3035 sizeof(*pool->cell_sort_array)));
3036 if (!pool->cell_sort_array) {
3037 *error = "Error allocating cell sort array";
3038 err_p = ERR_PTR(-ENOMEM);
3039 goto bad_sort_array;
3040 }
3041
3042 pool->ref_count = 1;
3043 pool->last_commit_jiffies = jiffies;
3044 pool->pool_md = pool_md;
3045 pool->md_dev = metadata_dev;
3046 pool->data_dev = data_dev;
3047 __pool_table_insert(pool);
3048
3049 return pool;
3050
3051bad_sort_array:
3052 mempool_exit(&pool->mapping_pool);
3053bad_mapping_pool:
3054 dm_deferred_set_destroy(pool->all_io_ds);
3055bad_all_io_ds:
3056 dm_deferred_set_destroy(pool->shared_read_ds);
3057bad_shared_read_ds:
3058 destroy_workqueue(pool->wq);
3059bad_wq:
3060 dm_kcopyd_client_destroy(pool->copier);
3061bad_kcopyd_client:
3062 dm_bio_prison_destroy(pool->prison);
3063bad_prison:
3064 kfree(pool);
3065bad_pool:
3066 if (dm_pool_metadata_close(pmd))
3067 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
3068
3069 return err_p;
3070}
3071
3072static void __pool_inc(struct pool *pool)
3073{
3074 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
3075 pool->ref_count++;
3076}
3077
3078static void __pool_dec(struct pool *pool)
3079{
3080 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
3081 BUG_ON(!pool->ref_count);
3082 if (!--pool->ref_count)
3083 __pool_destroy(pool);
3084}
3085
3086static struct pool *__pool_find(struct mapped_device *pool_md,
3087 struct block_device *metadata_dev,
3088 struct block_device *data_dev,
3089 unsigned long block_size, int read_only,
3090 char **error, int *created)
3091{
3092 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
3093
3094 if (pool) {
3095 if (pool->pool_md != pool_md) {
3096 *error = "metadata device already in use by a pool";
3097 return ERR_PTR(-EBUSY);
3098 }
3099 if (pool->data_dev != data_dev) {
3100 *error = "data device already in use by a pool";
3101 return ERR_PTR(-EBUSY);
3102 }
3103 __pool_inc(pool);
3104
3105 } else {
3106 pool = __pool_table_lookup(pool_md);
3107 if (pool) {
3108 if (pool->md_dev != metadata_dev || pool->data_dev != data_dev) {
3109 *error = "different pool cannot replace a pool";
3110 return ERR_PTR(-EINVAL);
3111 }
3112 __pool_inc(pool);
3113
3114 } else {
3115 pool = pool_create(pool_md, metadata_dev, data_dev, block_size, read_only, error);
3116 *created = 1;
3117 }
3118 }
3119
3120 return pool;
3121}
3122
3123/*
3124 *--------------------------------------------------------------
3125 * Pool target methods
3126 *--------------------------------------------------------------
3127 */
3128static void pool_dtr(struct dm_target *ti)
3129{
3130 struct pool_c *pt = ti->private;
3131
3132 mutex_lock(&dm_thin_pool_table.mutex);
3133
3134 unbind_control_target(pt->pool, ti);
3135 __pool_dec(pt->pool);
3136 dm_put_device(ti, pt->metadata_dev);
3137 dm_put_device(ti, pt->data_dev);
3138 kfree(pt);
3139
3140 mutex_unlock(&dm_thin_pool_table.mutex);
3141}
3142
3143static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
3144 struct dm_target *ti)
3145{
3146 int r;
3147 unsigned int argc;
3148 const char *arg_name;
3149
3150 static const struct dm_arg _args[] = {
3151 {0, 4, "Invalid number of pool feature arguments"},
3152 };
3153
3154 /*
3155 * No feature arguments supplied.
3156 */
3157 if (!as->argc)
3158 return 0;
3159
3160 r = dm_read_arg_group(_args, as, &argc, &ti->error);
3161 if (r)
3162 return -EINVAL;
3163
3164 while (argc && !r) {
3165 arg_name = dm_shift_arg(as);
3166 argc--;
3167
3168 if (!strcasecmp(arg_name, "skip_block_zeroing"))
3169 pf->zero_new_blocks = false;
3170
3171 else if (!strcasecmp(arg_name, "ignore_discard"))
3172 pf->discard_enabled = false;
3173
3174 else if (!strcasecmp(arg_name, "no_discard_passdown"))
3175 pf->discard_passdown = false;
3176
3177 else if (!strcasecmp(arg_name, "read_only"))
3178 pf->mode = PM_READ_ONLY;
3179
3180 else if (!strcasecmp(arg_name, "error_if_no_space"))
3181 pf->error_if_no_space = true;
3182
3183 else {
3184 ti->error = "Unrecognised pool feature requested";
3185 r = -EINVAL;
3186 break;
3187 }
3188 }
3189
3190 return r;
3191}
3192
3193static void metadata_low_callback(void *context)
3194{
3195 struct pool *pool = context;
3196
3197 DMWARN("%s: reached low water mark for metadata device: sending event.",
3198 dm_device_name(pool->pool_md));
3199
3200 dm_table_event(pool->ti->table);
3201}
3202
3203/*
3204 * We need to flush the data device **before** committing the metadata.
3205 *
3206 * This ensures that the data blocks of any newly inserted mappings are
3207 * properly written to non-volatile storage and won't be lost in case of a
3208 * crash.
3209 *
3210 * Failure to do so can result in data corruption in the case of internal or
3211 * external snapshots and in the case of newly provisioned blocks, when block
3212 * zeroing is enabled.
3213 */
3214static int metadata_pre_commit_callback(void *context)
3215{
3216 struct pool *pool = context;
3217
3218 return blkdev_issue_flush(pool->data_dev);
3219}
3220
3221static sector_t get_dev_size(struct block_device *bdev)
3222{
3223 return bdev_nr_sectors(bdev);
3224}
3225
3226static void warn_if_metadata_device_too_big(struct block_device *bdev)
3227{
3228 sector_t metadata_dev_size = get_dev_size(bdev);
3229
3230 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
3231 DMWARN("Metadata device %pg is larger than %u sectors: excess space will not be used.",
3232 bdev, THIN_METADATA_MAX_SECTORS);
3233}
3234
3235static sector_t get_metadata_dev_size(struct block_device *bdev)
3236{
3237 sector_t metadata_dev_size = get_dev_size(bdev);
3238
3239 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
3240 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
3241
3242 return metadata_dev_size;
3243}
3244
3245static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
3246{
3247 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
3248
3249 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
3250
3251 return metadata_dev_size;
3252}
3253
3254/*
3255 * When a metadata threshold is crossed a dm event is triggered, and
3256 * userland should respond by growing the metadata device. We could let
3257 * userland set the threshold, like we do with the data threshold, but I'm
3258 * not sure they know enough to do this well.
3259 */
3260static dm_block_t calc_metadata_threshold(struct pool_c *pt)
3261{
3262 /*
3263 * 4M is ample for all ops with the possible exception of thin
3264 * device deletion which is harmless if it fails (just retry the
3265 * delete after you've grown the device).
3266 */
3267 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
3268
3269 return min((dm_block_t)1024ULL /* 4M */, quarter);
3270}
3271
3272/*
3273 * thin-pool <metadata dev> <data dev>
3274 * <data block size (sectors)>
3275 * <low water mark (blocks)>
3276 * [<#feature args> [<arg>]*]
3277 *
3278 * Optional feature arguments are:
3279 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
3280 * ignore_discard: disable discard
3281 * no_discard_passdown: don't pass discards down to the data device
3282 * read_only: Don't allow any changes to be made to the pool metadata.
3283 * error_if_no_space: error IOs, instead of queueing, if no space.
3284 */
3285static int pool_ctr(struct dm_target *ti, unsigned int argc, char **argv)
3286{
3287 int r, pool_created = 0;
3288 struct pool_c *pt;
3289 struct pool *pool;
3290 struct pool_features pf;
3291 struct dm_arg_set as;
3292 struct dm_dev *data_dev;
3293 unsigned long block_size;
3294 dm_block_t low_water_blocks;
3295 struct dm_dev *metadata_dev;
3296 blk_mode_t metadata_mode;
3297
3298 /*
3299 * FIXME Remove validation from scope of lock.
3300 */
3301 mutex_lock(&dm_thin_pool_table.mutex);
3302
3303 if (argc < 4) {
3304 ti->error = "Invalid argument count";
3305 r = -EINVAL;
3306 goto out_unlock;
3307 }
3308
3309 as.argc = argc;
3310 as.argv = argv;
3311
3312 /* make sure metadata and data are different devices */
3313 if (!strcmp(argv[0], argv[1])) {
3314 ti->error = "Error setting metadata or data device";
3315 r = -EINVAL;
3316 goto out_unlock;
3317 }
3318
3319 /*
3320 * Set default pool features.
3321 */
3322 pool_features_init(&pf);
3323
3324 dm_consume_args(&as, 4);
3325 r = parse_pool_features(&as, &pf, ti);
3326 if (r)
3327 goto out_unlock;
3328
3329 metadata_mode = BLK_OPEN_READ |
3330 ((pf.mode == PM_READ_ONLY) ? 0 : BLK_OPEN_WRITE);
3331 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
3332 if (r) {
3333 ti->error = "Error opening metadata block device";
3334 goto out_unlock;
3335 }
3336 warn_if_metadata_device_too_big(metadata_dev->bdev);
3337
3338 r = dm_get_device(ti, argv[1], BLK_OPEN_READ | BLK_OPEN_WRITE, &data_dev);
3339 if (r) {
3340 ti->error = "Error getting data device";
3341 goto out_metadata;
3342 }
3343
3344 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
3345 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
3346 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
3347 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
3348 ti->error = "Invalid block size";
3349 r = -EINVAL;
3350 goto out;
3351 }
3352
3353 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
3354 ti->error = "Invalid low water mark";
3355 r = -EINVAL;
3356 goto out;
3357 }
3358
3359 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
3360 if (!pt) {
3361 r = -ENOMEM;
3362 goto out;
3363 }
3364
3365 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, data_dev->bdev,
3366 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
3367 if (IS_ERR(pool)) {
3368 r = PTR_ERR(pool);
3369 goto out_free_pt;
3370 }
3371
3372 /*
3373 * 'pool_created' reflects whether this is the first table load.
3374 * Top level discard support is not allowed to be changed after
3375 * initial load. This would require a pool reload to trigger thin
3376 * device changes.
3377 */
3378 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
3379 ti->error = "Discard support cannot be disabled once enabled";
3380 r = -EINVAL;
3381 goto out_flags_changed;
3382 }
3383
3384 pt->pool = pool;
3385 pt->ti = ti;
3386 pt->metadata_dev = metadata_dev;
3387 pt->data_dev = data_dev;
3388 pt->low_water_blocks = low_water_blocks;
3389 pt->adjusted_pf = pt->requested_pf = pf;
3390 ti->num_flush_bios = 1;
3391 ti->limit_swap_bios = true;
3392
3393 /*
3394 * Only need to enable discards if the pool should pass
3395 * them down to the data device. The thin device's discard
3396 * processing will cause mappings to be removed from the btree.
3397 */
3398 if (pf.discard_enabled && pf.discard_passdown) {
3399 ti->num_discard_bios = 1;
3400 /*
3401 * Setting 'discards_supported' circumvents the normal
3402 * stacking of discard limits (this keeps the pool and
3403 * thin devices' discard limits consistent).
3404 */
3405 ti->discards_supported = true;
3406 ti->max_discard_granularity = true;
3407 }
3408 ti->private = pt;
3409
3410 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
3411 calc_metadata_threshold(pt),
3412 metadata_low_callback,
3413 pool);
3414 if (r) {
3415 ti->error = "Error registering metadata threshold";
3416 goto out_flags_changed;
3417 }
3418
3419 dm_pool_register_pre_commit_callback(pool->pmd,
3420 metadata_pre_commit_callback, pool);
3421
3422 mutex_unlock(&dm_thin_pool_table.mutex);
3423
3424 return 0;
3425
3426out_flags_changed:
3427 __pool_dec(pool);
3428out_free_pt:
3429 kfree(pt);
3430out:
3431 dm_put_device(ti, data_dev);
3432out_metadata:
3433 dm_put_device(ti, metadata_dev);
3434out_unlock:
3435 mutex_unlock(&dm_thin_pool_table.mutex);
3436
3437 return r;
3438}
3439
3440static int pool_map(struct dm_target *ti, struct bio *bio)
3441{
3442 struct pool_c *pt = ti->private;
3443 struct pool *pool = pt->pool;
3444
3445 /*
3446 * As this is a singleton target, ti->begin is always zero.
3447 */
3448 spin_lock_irq(&pool->lock);
3449 bio_set_dev(bio, pt->data_dev->bdev);
3450 spin_unlock_irq(&pool->lock);
3451
3452 return DM_MAPIO_REMAPPED;
3453}
3454
3455static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
3456{
3457 int r;
3458 struct pool_c *pt = ti->private;
3459 struct pool *pool = pt->pool;
3460 sector_t data_size = ti->len;
3461 dm_block_t sb_data_size;
3462
3463 *need_commit = false;
3464
3465 (void) sector_div(data_size, pool->sectors_per_block);
3466
3467 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
3468 if (r) {
3469 DMERR("%s: failed to retrieve data device size",
3470 dm_device_name(pool->pool_md));
3471 return r;
3472 }
3473
3474 if (data_size < sb_data_size) {
3475 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
3476 dm_device_name(pool->pool_md),
3477 (unsigned long long)data_size, sb_data_size);
3478 return -EINVAL;
3479
3480 } else if (data_size > sb_data_size) {
3481 if (dm_pool_metadata_needs_check(pool->pmd)) {
3482 DMERR("%s: unable to grow the data device until repaired.",
3483 dm_device_name(pool->pool_md));
3484 return 0;
3485 }
3486
3487 if (sb_data_size)
3488 DMINFO("%s: growing the data device from %llu to %llu blocks",
3489 dm_device_name(pool->pool_md),
3490 sb_data_size, (unsigned long long)data_size);
3491 r = dm_pool_resize_data_dev(pool->pmd, data_size);
3492 if (r) {
3493 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
3494 return r;
3495 }
3496
3497 *need_commit = true;
3498 }
3499
3500 return 0;
3501}
3502
3503static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
3504{
3505 int r;
3506 struct pool_c *pt = ti->private;
3507 struct pool *pool = pt->pool;
3508 dm_block_t metadata_dev_size, sb_metadata_dev_size;
3509
3510 *need_commit = false;
3511
3512 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
3513
3514 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
3515 if (r) {
3516 DMERR("%s: failed to retrieve metadata device size",
3517 dm_device_name(pool->pool_md));
3518 return r;
3519 }
3520
3521 if (metadata_dev_size < sb_metadata_dev_size) {
3522 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
3523 dm_device_name(pool->pool_md),
3524 metadata_dev_size, sb_metadata_dev_size);
3525 return -EINVAL;
3526
3527 } else if (metadata_dev_size > sb_metadata_dev_size) {
3528 if (dm_pool_metadata_needs_check(pool->pmd)) {
3529 DMERR("%s: unable to grow the metadata device until repaired.",
3530 dm_device_name(pool->pool_md));
3531 return 0;
3532 }
3533
3534 warn_if_metadata_device_too_big(pool->md_dev);
3535 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
3536 dm_device_name(pool->pool_md),
3537 sb_metadata_dev_size, metadata_dev_size);
3538
3539 if (get_pool_mode(pool) == PM_OUT_OF_METADATA_SPACE)
3540 set_pool_mode(pool, PM_WRITE);
3541
3542 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
3543 if (r) {
3544 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
3545 return r;
3546 }
3547
3548 *need_commit = true;
3549 }
3550
3551 return 0;
3552}
3553
3554/*
3555 * Retrieves the number of blocks of the data device from
3556 * the superblock and compares it to the actual device size,
3557 * thus resizing the data device in case it has grown.
3558 *
3559 * This both copes with opening preallocated data devices in the ctr
3560 * being followed by a resume
3561 * -and-
3562 * calling the resume method individually after userspace has
3563 * grown the data device in reaction to a table event.
3564 */
3565static int pool_preresume(struct dm_target *ti)
3566{
3567 int r;
3568 bool need_commit1, need_commit2;
3569 struct pool_c *pt = ti->private;
3570 struct pool *pool = pt->pool;
3571
3572 /*
3573 * Take control of the pool object.
3574 */
3575 r = bind_control_target(pool, ti);
3576 if (r)
3577 goto out;
3578
3579 r = maybe_resize_data_dev(ti, &need_commit1);
3580 if (r)
3581 goto out;
3582
3583 r = maybe_resize_metadata_dev(ti, &need_commit2);
3584 if (r)
3585 goto out;
3586
3587 if (need_commit1 || need_commit2)
3588 (void) commit(pool);
3589out:
3590 /*
3591 * When a thin-pool is PM_FAIL, it cannot be rebuilt if
3592 * bio is in deferred list. Therefore need to return 0
3593 * to allow pool_resume() to flush IO.
3594 */
3595 if (r && get_pool_mode(pool) == PM_FAIL)
3596 r = 0;
3597
3598 return r;
3599}
3600
3601static void pool_suspend_active_thins(struct pool *pool)
3602{
3603 struct thin_c *tc;
3604
3605 /* Suspend all active thin devices */
3606 tc = get_first_thin(pool);
3607 while (tc) {
3608 dm_internal_suspend_noflush(tc->thin_md);
3609 tc = get_next_thin(pool, tc);
3610 }
3611}
3612
3613static void pool_resume_active_thins(struct pool *pool)
3614{
3615 struct thin_c *tc;
3616
3617 /* Resume all active thin devices */
3618 tc = get_first_thin(pool);
3619 while (tc) {
3620 dm_internal_resume(tc->thin_md);
3621 tc = get_next_thin(pool, tc);
3622 }
3623}
3624
3625static void pool_resume(struct dm_target *ti)
3626{
3627 struct pool_c *pt = ti->private;
3628 struct pool *pool = pt->pool;
3629
3630 /*
3631 * Must requeue active_thins' bios and then resume
3632 * active_thins _before_ clearing 'suspend' flag.
3633 */
3634 requeue_bios(pool);
3635 pool_resume_active_thins(pool);
3636
3637 spin_lock_irq(&pool->lock);
3638 pool->low_water_triggered = false;
3639 pool->suspended = false;
3640 spin_unlock_irq(&pool->lock);
3641
3642 do_waker(&pool->waker.work);
3643}
3644
3645static void pool_presuspend(struct dm_target *ti)
3646{
3647 struct pool_c *pt = ti->private;
3648 struct pool *pool = pt->pool;
3649
3650 spin_lock_irq(&pool->lock);
3651 pool->suspended = true;
3652 spin_unlock_irq(&pool->lock);
3653
3654 pool_suspend_active_thins(pool);
3655}
3656
3657static void pool_presuspend_undo(struct dm_target *ti)
3658{
3659 struct pool_c *pt = ti->private;
3660 struct pool *pool = pt->pool;
3661
3662 pool_resume_active_thins(pool);
3663
3664 spin_lock_irq(&pool->lock);
3665 pool->suspended = false;
3666 spin_unlock_irq(&pool->lock);
3667}
3668
3669static void pool_postsuspend(struct dm_target *ti)
3670{
3671 struct pool_c *pt = ti->private;
3672 struct pool *pool = pt->pool;
3673
3674 cancel_delayed_work_sync(&pool->waker);
3675 cancel_delayed_work_sync(&pool->no_space_timeout);
3676 flush_workqueue(pool->wq);
3677 (void) commit(pool);
3678}
3679
3680static int check_arg_count(unsigned int argc, unsigned int args_required)
3681{
3682 if (argc != args_required) {
3683 DMWARN("Message received with %u arguments instead of %u.",
3684 argc, args_required);
3685 return -EINVAL;
3686 }
3687
3688 return 0;
3689}
3690
3691static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
3692{
3693 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
3694 *dev_id <= MAX_DEV_ID)
3695 return 0;
3696
3697 if (warning)
3698 DMWARN("Message received with invalid device id: %s", arg);
3699
3700 return -EINVAL;
3701}
3702
3703static int process_create_thin_mesg(unsigned int argc, char **argv, struct pool *pool)
3704{
3705 dm_thin_id dev_id;
3706 int r;
3707
3708 r = check_arg_count(argc, 2);
3709 if (r)
3710 return r;
3711
3712 r = read_dev_id(argv[1], &dev_id, 1);
3713 if (r)
3714 return r;
3715
3716 r = dm_pool_create_thin(pool->pmd, dev_id);
3717 if (r) {
3718 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
3719 argv[1]);
3720 return r;
3721 }
3722
3723 return 0;
3724}
3725
3726static int process_create_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3727{
3728 dm_thin_id dev_id;
3729 dm_thin_id origin_dev_id;
3730 int r;
3731
3732 r = check_arg_count(argc, 3);
3733 if (r)
3734 return r;
3735
3736 r = read_dev_id(argv[1], &dev_id, 1);
3737 if (r)
3738 return r;
3739
3740 r = read_dev_id(argv[2], &origin_dev_id, 1);
3741 if (r)
3742 return r;
3743
3744 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
3745 if (r) {
3746 DMWARN("Creation of new snapshot %s of device %s failed.",
3747 argv[1], argv[2]);
3748 return r;
3749 }
3750
3751 return 0;
3752}
3753
3754static int process_delete_mesg(unsigned int argc, char **argv, struct pool *pool)
3755{
3756 dm_thin_id dev_id;
3757 int r;
3758
3759 r = check_arg_count(argc, 2);
3760 if (r)
3761 return r;
3762
3763 r = read_dev_id(argv[1], &dev_id, 1);
3764 if (r)
3765 return r;
3766
3767 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
3768 if (r)
3769 DMWARN("Deletion of thin device %s failed.", argv[1]);
3770
3771 return r;
3772}
3773
3774static int process_set_transaction_id_mesg(unsigned int argc, char **argv, struct pool *pool)
3775{
3776 dm_thin_id old_id, new_id;
3777 int r;
3778
3779 r = check_arg_count(argc, 3);
3780 if (r)
3781 return r;
3782
3783 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
3784 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
3785 return -EINVAL;
3786 }
3787
3788 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
3789 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
3790 return -EINVAL;
3791 }
3792
3793 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
3794 if (r) {
3795 DMWARN("Failed to change transaction id from %s to %s.",
3796 argv[1], argv[2]);
3797 return r;
3798 }
3799
3800 return 0;
3801}
3802
3803static int process_reserve_metadata_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3804{
3805 int r;
3806
3807 r = check_arg_count(argc, 1);
3808 if (r)
3809 return r;
3810
3811 (void) commit(pool);
3812
3813 r = dm_pool_reserve_metadata_snap(pool->pmd);
3814 if (r)
3815 DMWARN("reserve_metadata_snap message failed.");
3816
3817 return r;
3818}
3819
3820static int process_release_metadata_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3821{
3822 int r;
3823
3824 r = check_arg_count(argc, 1);
3825 if (r)
3826 return r;
3827
3828 r = dm_pool_release_metadata_snap(pool->pmd);
3829 if (r)
3830 DMWARN("release_metadata_snap message failed.");
3831
3832 return r;
3833}
3834
3835/*
3836 * Messages supported:
3837 * create_thin <dev_id>
3838 * create_snap <dev_id> <origin_id>
3839 * delete <dev_id>
3840 * set_transaction_id <current_trans_id> <new_trans_id>
3841 * reserve_metadata_snap
3842 * release_metadata_snap
3843 */
3844static int pool_message(struct dm_target *ti, unsigned int argc, char **argv,
3845 char *result, unsigned int maxlen)
3846{
3847 int r = -EINVAL;
3848 struct pool_c *pt = ti->private;
3849 struct pool *pool = pt->pool;
3850
3851 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE) {
3852 DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode",
3853 dm_device_name(pool->pool_md));
3854 return -EOPNOTSUPP;
3855 }
3856
3857 if (!strcasecmp(argv[0], "create_thin"))
3858 r = process_create_thin_mesg(argc, argv, pool);
3859
3860 else if (!strcasecmp(argv[0], "create_snap"))
3861 r = process_create_snap_mesg(argc, argv, pool);
3862
3863 else if (!strcasecmp(argv[0], "delete"))
3864 r = process_delete_mesg(argc, argv, pool);
3865
3866 else if (!strcasecmp(argv[0], "set_transaction_id"))
3867 r = process_set_transaction_id_mesg(argc, argv, pool);
3868
3869 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
3870 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
3871
3872 else if (!strcasecmp(argv[0], "release_metadata_snap"))
3873 r = process_release_metadata_snap_mesg(argc, argv, pool);
3874
3875 else
3876 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
3877
3878 if (!r)
3879 (void) commit(pool);
3880
3881 return r;
3882}
3883
3884static void emit_flags(struct pool_features *pf, char *result,
3885 unsigned int sz, unsigned int maxlen)
3886{
3887 unsigned int count = !pf->zero_new_blocks + !pf->discard_enabled +
3888 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
3889 pf->error_if_no_space;
3890 DMEMIT("%u ", count);
3891
3892 if (!pf->zero_new_blocks)
3893 DMEMIT("skip_block_zeroing ");
3894
3895 if (!pf->discard_enabled)
3896 DMEMIT("ignore_discard ");
3897
3898 if (!pf->discard_passdown)
3899 DMEMIT("no_discard_passdown ");
3900
3901 if (pf->mode == PM_READ_ONLY)
3902 DMEMIT("read_only ");
3903
3904 if (pf->error_if_no_space)
3905 DMEMIT("error_if_no_space ");
3906}
3907
3908/*
3909 * Status line is:
3910 * <transaction id> <used metadata sectors>/<total metadata sectors>
3911 * <used data sectors>/<total data sectors> <held metadata root>
3912 * <pool mode> <discard config> <no space config> <needs_check>
3913 */
3914static void pool_status(struct dm_target *ti, status_type_t type,
3915 unsigned int status_flags, char *result, unsigned int maxlen)
3916{
3917 int r;
3918 unsigned int sz = 0;
3919 uint64_t transaction_id;
3920 dm_block_t nr_free_blocks_data;
3921 dm_block_t nr_free_blocks_metadata;
3922 dm_block_t nr_blocks_data;
3923 dm_block_t nr_blocks_metadata;
3924 dm_block_t held_root;
3925 enum pool_mode mode;
3926 char buf[BDEVNAME_SIZE];
3927 char buf2[BDEVNAME_SIZE];
3928 struct pool_c *pt = ti->private;
3929 struct pool *pool = pt->pool;
3930
3931 switch (type) {
3932 case STATUSTYPE_INFO:
3933 if (get_pool_mode(pool) == PM_FAIL) {
3934 DMEMIT("Fail");
3935 break;
3936 }
3937
3938 /* Commit to ensure statistics aren't out-of-date */
3939 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3940 (void) commit(pool);
3941
3942 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
3943 if (r) {
3944 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
3945 dm_device_name(pool->pool_md), r);
3946 goto err;
3947 }
3948
3949 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
3950 if (r) {
3951 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
3952 dm_device_name(pool->pool_md), r);
3953 goto err;
3954 }
3955
3956 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
3957 if (r) {
3958 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
3959 dm_device_name(pool->pool_md), r);
3960 goto err;
3961 }
3962
3963 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
3964 if (r) {
3965 DMERR("%s: dm_pool_get_free_block_count returned %d",
3966 dm_device_name(pool->pool_md), r);
3967 goto err;
3968 }
3969
3970 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
3971 if (r) {
3972 DMERR("%s: dm_pool_get_data_dev_size returned %d",
3973 dm_device_name(pool->pool_md), r);
3974 goto err;
3975 }
3976
3977 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
3978 if (r) {
3979 DMERR("%s: dm_pool_get_metadata_snap returned %d",
3980 dm_device_name(pool->pool_md), r);
3981 goto err;
3982 }
3983
3984 DMEMIT("%llu %llu/%llu %llu/%llu ",
3985 (unsigned long long)transaction_id,
3986 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3987 (unsigned long long)nr_blocks_metadata,
3988 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
3989 (unsigned long long)nr_blocks_data);
3990
3991 if (held_root)
3992 DMEMIT("%llu ", held_root);
3993 else
3994 DMEMIT("- ");
3995
3996 mode = get_pool_mode(pool);
3997 if (mode == PM_OUT_OF_DATA_SPACE)
3998 DMEMIT("out_of_data_space ");
3999 else if (is_read_only_pool_mode(mode))
4000 DMEMIT("ro ");
4001 else
4002 DMEMIT("rw ");
4003
4004 if (!pool->pf.discard_enabled)
4005 DMEMIT("ignore_discard ");
4006 else if (pool->pf.discard_passdown)
4007 DMEMIT("discard_passdown ");
4008 else
4009 DMEMIT("no_discard_passdown ");
4010
4011 if (pool->pf.error_if_no_space)
4012 DMEMIT("error_if_no_space ");
4013 else
4014 DMEMIT("queue_if_no_space ");
4015
4016 if (dm_pool_metadata_needs_check(pool->pmd))
4017 DMEMIT("needs_check ");
4018 else
4019 DMEMIT("- ");
4020
4021 DMEMIT("%llu ", (unsigned long long)calc_metadata_threshold(pt));
4022
4023 break;
4024
4025 case STATUSTYPE_TABLE:
4026 DMEMIT("%s %s %lu %llu ",
4027 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
4028 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
4029 (unsigned long)pool->sectors_per_block,
4030 (unsigned long long)pt->low_water_blocks);
4031 emit_flags(&pt->requested_pf, result, sz, maxlen);
4032 break;
4033
4034 case STATUSTYPE_IMA:
4035 *result = '\0';
4036 break;
4037 }
4038 return;
4039
4040err:
4041 DMEMIT("Error");
4042}
4043
4044static int pool_iterate_devices(struct dm_target *ti,
4045 iterate_devices_callout_fn fn, void *data)
4046{
4047 struct pool_c *pt = ti->private;
4048
4049 return fn(ti, pt->data_dev, 0, ti->len, data);
4050}
4051
4052static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
4053{
4054 struct pool_c *pt = ti->private;
4055 struct pool *pool = pt->pool;
4056 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
4057
4058 /*
4059 * If max_sectors is smaller than pool->sectors_per_block adjust it
4060 * to the highest possible power-of-2 factor of pool->sectors_per_block.
4061 * This is especially beneficial when the pool's data device is a RAID
4062 * device that has a full stripe width that matches pool->sectors_per_block
4063 * -- because even though partial RAID stripe-sized IOs will be issued to a
4064 * single RAID stripe; when aggregated they will end on a full RAID stripe
4065 * boundary.. which avoids additional partial RAID stripe writes cascading
4066 */
4067 if (limits->max_sectors < pool->sectors_per_block) {
4068 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
4069 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
4070 limits->max_sectors--;
4071 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
4072 }
4073 }
4074
4075 /*
4076 * If the system-determined stacked limits are compatible with the
4077 * pool's blocksize (io_opt is a factor) do not override them.
4078 */
4079 if (io_opt_sectors < pool->sectors_per_block ||
4080 !is_factor(io_opt_sectors, pool->sectors_per_block)) {
4081 if (is_factor(pool->sectors_per_block, limits->max_sectors))
4082 limits->io_min = limits->max_sectors << SECTOR_SHIFT;
4083 else
4084 limits->io_min = pool->sectors_per_block << SECTOR_SHIFT;
4085 limits->io_opt = pool->sectors_per_block << SECTOR_SHIFT;
4086 }
4087
4088 /*
4089 * pt->adjusted_pf is a staging area for the actual features to use.
4090 * They get transferred to the live pool in bind_control_target()
4091 * called from pool_preresume().
4092 */
4093
4094 if (pt->adjusted_pf.discard_enabled) {
4095 disable_discard_passdown_if_not_supported(pt);
4096 if (!pt->adjusted_pf.discard_passdown)
4097 limits->max_hw_discard_sectors = 0;
4098 /*
4099 * The pool uses the same discard limits as the underlying data
4100 * device. DM core has already set this up.
4101 */
4102 } else {
4103 /*
4104 * Must explicitly disallow stacking discard limits otherwise the
4105 * block layer will stack them if pool's data device has support.
4106 */
4107 limits->discard_granularity = 0;
4108 }
4109}
4110
4111static struct target_type pool_target = {
4112 .name = "thin-pool",
4113 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
4114 DM_TARGET_IMMUTABLE,
4115 .version = {1, 23, 0},
4116 .module = THIS_MODULE,
4117 .ctr = pool_ctr,
4118 .dtr = pool_dtr,
4119 .map = pool_map,
4120 .presuspend = pool_presuspend,
4121 .presuspend_undo = pool_presuspend_undo,
4122 .postsuspend = pool_postsuspend,
4123 .preresume = pool_preresume,
4124 .resume = pool_resume,
4125 .message = pool_message,
4126 .status = pool_status,
4127 .iterate_devices = pool_iterate_devices,
4128 .io_hints = pool_io_hints,
4129};
4130
4131/*
4132 *--------------------------------------------------------------
4133 * Thin target methods
4134 *--------------------------------------------------------------
4135 */
4136static void thin_get(struct thin_c *tc)
4137{
4138 refcount_inc(&tc->refcount);
4139}
4140
4141static void thin_put(struct thin_c *tc)
4142{
4143 if (refcount_dec_and_test(&tc->refcount))
4144 complete(&tc->can_destroy);
4145}
4146
4147static void thin_dtr(struct dm_target *ti)
4148{
4149 struct thin_c *tc = ti->private;
4150
4151 spin_lock_irq(&tc->pool->lock);
4152 list_del_rcu(&tc->list);
4153 spin_unlock_irq(&tc->pool->lock);
4154 synchronize_rcu();
4155
4156 thin_put(tc);
4157 wait_for_completion(&tc->can_destroy);
4158
4159 mutex_lock(&dm_thin_pool_table.mutex);
4160
4161 __pool_dec(tc->pool);
4162 dm_pool_close_thin_device(tc->td);
4163 dm_put_device(ti, tc->pool_dev);
4164 if (tc->origin_dev)
4165 dm_put_device(ti, tc->origin_dev);
4166 kfree(tc);
4167
4168 mutex_unlock(&dm_thin_pool_table.mutex);
4169}
4170
4171/*
4172 * Thin target parameters:
4173 *
4174 * <pool_dev> <dev_id> [origin_dev]
4175 *
4176 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
4177 * dev_id: the internal device identifier
4178 * origin_dev: a device external to the pool that should act as the origin
4179 *
4180 * If the pool device has discards disabled, they get disabled for the thin
4181 * device as well.
4182 */
4183static int thin_ctr(struct dm_target *ti, unsigned int argc, char **argv)
4184{
4185 int r;
4186 struct thin_c *tc;
4187 struct dm_dev *pool_dev, *origin_dev;
4188 struct mapped_device *pool_md;
4189
4190 mutex_lock(&dm_thin_pool_table.mutex);
4191
4192 if (argc != 2 && argc != 3) {
4193 ti->error = "Invalid argument count";
4194 r = -EINVAL;
4195 goto out_unlock;
4196 }
4197
4198 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
4199 if (!tc) {
4200 ti->error = "Out of memory";
4201 r = -ENOMEM;
4202 goto out_unlock;
4203 }
4204 tc->thin_md = dm_table_get_md(ti->table);
4205 spin_lock_init(&tc->lock);
4206 INIT_LIST_HEAD(&tc->deferred_cells);
4207 bio_list_init(&tc->deferred_bio_list);
4208 bio_list_init(&tc->retry_on_resume_list);
4209 tc->sort_bio_list = RB_ROOT;
4210
4211 if (argc == 3) {
4212 if (!strcmp(argv[0], argv[2])) {
4213 ti->error = "Error setting origin device";
4214 r = -EINVAL;
4215 goto bad_origin_dev;
4216 }
4217
4218 r = dm_get_device(ti, argv[2], BLK_OPEN_READ, &origin_dev);
4219 if (r) {
4220 ti->error = "Error opening origin device";
4221 goto bad_origin_dev;
4222 }
4223 tc->origin_dev = origin_dev;
4224 }
4225
4226 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
4227 if (r) {
4228 ti->error = "Error opening pool device";
4229 goto bad_pool_dev;
4230 }
4231 tc->pool_dev = pool_dev;
4232
4233 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
4234 ti->error = "Invalid device id";
4235 r = -EINVAL;
4236 goto bad_common;
4237 }
4238
4239 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
4240 if (!pool_md) {
4241 ti->error = "Couldn't get pool mapped device";
4242 r = -EINVAL;
4243 goto bad_common;
4244 }
4245
4246 tc->pool = __pool_table_lookup(pool_md);
4247 if (!tc->pool) {
4248 ti->error = "Couldn't find pool object";
4249 r = -EINVAL;
4250 goto bad_pool_lookup;
4251 }
4252 __pool_inc(tc->pool);
4253
4254 if (get_pool_mode(tc->pool) == PM_FAIL) {
4255 ti->error = "Couldn't open thin device, Pool is in fail mode";
4256 r = -EINVAL;
4257 goto bad_pool;
4258 }
4259
4260 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
4261 if (r) {
4262 ti->error = "Couldn't open thin internal device";
4263 goto bad_pool;
4264 }
4265
4266 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
4267 if (r)
4268 goto bad;
4269
4270 ti->num_flush_bios = 1;
4271 ti->limit_swap_bios = true;
4272 ti->flush_supported = true;
4273 ti->accounts_remapped_io = true;
4274 ti->per_io_data_size = sizeof(struct dm_thin_endio_hook);
4275
4276 /* In case the pool supports discards, pass them on. */
4277 if (tc->pool->pf.discard_enabled) {
4278 ti->discards_supported = true;
4279 ti->num_discard_bios = 1;
4280 ti->max_discard_granularity = true;
4281 }
4282
4283 mutex_unlock(&dm_thin_pool_table.mutex);
4284
4285 spin_lock_irq(&tc->pool->lock);
4286 if (tc->pool->suspended) {
4287 spin_unlock_irq(&tc->pool->lock);
4288 mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */
4289 ti->error = "Unable to activate thin device while pool is suspended";
4290 r = -EINVAL;
4291 goto bad;
4292 }
4293 refcount_set(&tc->refcount, 1);
4294 init_completion(&tc->can_destroy);
4295 list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
4296 spin_unlock_irq(&tc->pool->lock);
4297 /*
4298 * This synchronize_rcu() call is needed here otherwise we risk a
4299 * wake_worker() call finding no bios to process (because the newly
4300 * added tc isn't yet visible). So this reduces latency since we
4301 * aren't then dependent on the periodic commit to wake_worker().
4302 */
4303 synchronize_rcu();
4304
4305 dm_put(pool_md);
4306
4307 return 0;
4308
4309bad:
4310 dm_pool_close_thin_device(tc->td);
4311bad_pool:
4312 __pool_dec(tc->pool);
4313bad_pool_lookup:
4314 dm_put(pool_md);
4315bad_common:
4316 dm_put_device(ti, tc->pool_dev);
4317bad_pool_dev:
4318 if (tc->origin_dev)
4319 dm_put_device(ti, tc->origin_dev);
4320bad_origin_dev:
4321 kfree(tc);
4322out_unlock:
4323 mutex_unlock(&dm_thin_pool_table.mutex);
4324
4325 return r;
4326}
4327
4328static int thin_map(struct dm_target *ti, struct bio *bio)
4329{
4330 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
4331
4332 return thin_bio_map(ti, bio);
4333}
4334
4335static int thin_endio(struct dm_target *ti, struct bio *bio,
4336 blk_status_t *err)
4337{
4338 unsigned long flags;
4339 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
4340 struct list_head work;
4341 struct dm_thin_new_mapping *m, *tmp;
4342 struct pool *pool = h->tc->pool;
4343
4344 if (h->shared_read_entry) {
4345 INIT_LIST_HEAD(&work);
4346 dm_deferred_entry_dec(h->shared_read_entry, &work);
4347
4348 spin_lock_irqsave(&pool->lock, flags);
4349 list_for_each_entry_safe(m, tmp, &work, list) {
4350 list_del(&m->list);
4351 __complete_mapping_preparation(m);
4352 }
4353 spin_unlock_irqrestore(&pool->lock, flags);
4354 }
4355
4356 if (h->all_io_entry) {
4357 INIT_LIST_HEAD(&work);
4358 dm_deferred_entry_dec(h->all_io_entry, &work);
4359 if (!list_empty(&work)) {
4360 spin_lock_irqsave(&pool->lock, flags);
4361 list_for_each_entry_safe(m, tmp, &work, list)
4362 list_add_tail(&m->list, &pool->prepared_discards);
4363 spin_unlock_irqrestore(&pool->lock, flags);
4364 wake_worker(pool);
4365 }
4366 }
4367
4368 if (h->cell)
4369 cell_defer_no_holder(h->tc, h->cell);
4370
4371 return DM_ENDIO_DONE;
4372}
4373
4374static void thin_presuspend(struct dm_target *ti)
4375{
4376 struct thin_c *tc = ti->private;
4377
4378 if (dm_noflush_suspending(ti))
4379 noflush_work(tc, do_noflush_start);
4380}
4381
4382static void thin_postsuspend(struct dm_target *ti)
4383{
4384 struct thin_c *tc = ti->private;
4385
4386 /*
4387 * The dm_noflush_suspending flag has been cleared by now, so
4388 * unfortunately we must always run this.
4389 */
4390 noflush_work(tc, do_noflush_stop);
4391}
4392
4393static int thin_preresume(struct dm_target *ti)
4394{
4395 struct thin_c *tc = ti->private;
4396
4397 if (tc->origin_dev)
4398 tc->origin_size = get_dev_size(tc->origin_dev->bdev);
4399
4400 return 0;
4401}
4402
4403/*
4404 * <nr mapped sectors> <highest mapped sector>
4405 */
4406static void thin_status(struct dm_target *ti, status_type_t type,
4407 unsigned int status_flags, char *result, unsigned int maxlen)
4408{
4409 int r;
4410 ssize_t sz = 0;
4411 dm_block_t mapped, highest;
4412 char buf[BDEVNAME_SIZE];
4413 struct thin_c *tc = ti->private;
4414
4415 if (get_pool_mode(tc->pool) == PM_FAIL) {
4416 DMEMIT("Fail");
4417 return;
4418 }
4419
4420 if (!tc->td)
4421 DMEMIT("-");
4422 else {
4423 switch (type) {
4424 case STATUSTYPE_INFO:
4425 r = dm_thin_get_mapped_count(tc->td, &mapped);
4426 if (r) {
4427 DMERR("dm_thin_get_mapped_count returned %d", r);
4428 goto err;
4429 }
4430
4431 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
4432 if (r < 0) {
4433 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
4434 goto err;
4435 }
4436
4437 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
4438 if (r)
4439 DMEMIT("%llu", ((highest + 1) *
4440 tc->pool->sectors_per_block) - 1);
4441 else
4442 DMEMIT("-");
4443 break;
4444
4445 case STATUSTYPE_TABLE:
4446 DMEMIT("%s %lu",
4447 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
4448 (unsigned long) tc->dev_id);
4449 if (tc->origin_dev)
4450 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
4451 break;
4452
4453 case STATUSTYPE_IMA:
4454 *result = '\0';
4455 break;
4456 }
4457 }
4458
4459 return;
4460
4461err:
4462 DMEMIT("Error");
4463}
4464
4465static int thin_iterate_devices(struct dm_target *ti,
4466 iterate_devices_callout_fn fn, void *data)
4467{
4468 sector_t blocks;
4469 struct thin_c *tc = ti->private;
4470 struct pool *pool = tc->pool;
4471
4472 /*
4473 * We can't call dm_pool_get_data_dev_size() since that blocks. So
4474 * we follow a more convoluted path through to the pool's target.
4475 */
4476 if (!pool->ti)
4477 return 0; /* nothing is bound */
4478
4479 blocks = pool->ti->len;
4480 (void) sector_div(blocks, pool->sectors_per_block);
4481 if (blocks)
4482 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
4483
4484 return 0;
4485}
4486
4487static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
4488{
4489 struct thin_c *tc = ti->private;
4490 struct pool *pool = tc->pool;
4491
4492 if (pool->pf.discard_enabled) {
4493 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
4494 limits->max_hw_discard_sectors = pool->sectors_per_block * BIO_PRISON_MAX_RANGE;
4495 }
4496}
4497
4498static struct target_type thin_target = {
4499 .name = "thin",
4500 .version = {1, 23, 0},
4501 .module = THIS_MODULE,
4502 .ctr = thin_ctr,
4503 .dtr = thin_dtr,
4504 .map = thin_map,
4505 .end_io = thin_endio,
4506 .preresume = thin_preresume,
4507 .presuspend = thin_presuspend,
4508 .postsuspend = thin_postsuspend,
4509 .status = thin_status,
4510 .iterate_devices = thin_iterate_devices,
4511 .io_hints = thin_io_hints,
4512};
4513
4514/*----------------------------------------------------------------*/
4515
4516static int __init dm_thin_init(void)
4517{
4518 int r = -ENOMEM;
4519
4520 pool_table_init();
4521
4522 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
4523 if (!_new_mapping_cache)
4524 return r;
4525
4526 r = dm_register_target(&thin_target);
4527 if (r)
4528 goto bad_new_mapping_cache;
4529
4530 r = dm_register_target(&pool_target);
4531 if (r)
4532 goto bad_thin_target;
4533
4534 return 0;
4535
4536bad_thin_target:
4537 dm_unregister_target(&thin_target);
4538bad_new_mapping_cache:
4539 kmem_cache_destroy(_new_mapping_cache);
4540
4541 return r;
4542}
4543
4544static void dm_thin_exit(void)
4545{
4546 dm_unregister_target(&thin_target);
4547 dm_unregister_target(&pool_target);
4548
4549 kmem_cache_destroy(_new_mapping_cache);
4550
4551 pool_table_exit();
4552}
4553
4554module_init(dm_thin_init);
4555module_exit(dm_thin_exit);
4556
4557module_param_named(no_space_timeout, no_space_timeout_secs, uint, 0644);
4558MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
4559
4560MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
4561MODULE_AUTHOR("Joe Thornber <dm-devel@lists.linux.dev>");
4562MODULE_LICENSE("GPL");