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