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