blob: c3087575fef0ffe5330c261a721abddef3f6771e [file] [log] [blame]
Joe Thornber991d9fa2011-10-31 20:21:18 +00001/*
2 * Copyright (C) 2011 Red Hat UK.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-thin-metadata.h"
8
9#include <linux/device-mapper.h>
10#include <linux/dm-io.h>
11#include <linux/dm-kcopyd.h>
12#include <linux/list.h>
13#include <linux/init.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16
17#define DM_MSG_PREFIX "thin"
18
19/*
20 * Tunable constants
21 */
22#define ENDIO_HOOK_POOL_SIZE 10240
23#define DEFERRED_SET_SIZE 64
24#define MAPPING_POOL_SIZE 1024
25#define PRISON_CELLS 1024
26
27/*
28 * The block size of the device holding pool data must be
29 * between 64KB and 1GB.
30 */
31#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
32#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
33
34/*
35 * The metadata device is currently limited in size. The limitation is
36 * checked lower down in dm-space-map-metadata, but we also check it here
37 * so we can fail early.
38 *
39 * We have one block of index, which can hold 255 index entries. Each
40 * index entry contains allocation info about 16k metadata blocks.
41 */
42#define METADATA_DEV_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT)))
43
44/*
45 * Device id is restricted to 24 bits.
46 */
47#define MAX_DEV_ID ((1 << 24) - 1)
48
49/*
50 * How do we handle breaking sharing of data blocks?
51 * =================================================
52 *
53 * We use a standard copy-on-write btree to store the mappings for the
54 * devices (note I'm talking about copy-on-write of the metadata here, not
55 * the data). When you take an internal snapshot you clone the root node
56 * of the origin btree. After this there is no concept of an origin or a
57 * snapshot. They are just two device trees that happen to point to the
58 * same data blocks.
59 *
60 * When we get a write in we decide if it's to a shared data block using
61 * some timestamp magic. If it is, we have to break sharing.
62 *
63 * Let's say we write to a shared block in what was the origin. The
64 * steps are:
65 *
66 * i) plug io further to this physical block. (see bio_prison code).
67 *
68 * ii) quiesce any read io to that shared data block. Obviously
69 * including all devices that share this block. (see deferred_set code)
70 *
71 * iii) copy the data block to a newly allocate block. This step can be
72 * missed out if the io covers the block. (schedule_copy).
73 *
74 * iv) insert the new mapping into the origin's btree
75 * (process_prepared_mappings). This act of inserting breaks some
76 * sharing of btree nodes between the two devices. Breaking sharing only
77 * effects the btree of that specific device. Btrees for the other
78 * devices that share the block never change. The btree for the origin
79 * device as it was after the last commit is untouched, ie. we're using
80 * persistent data structures in the functional programming sense.
81 *
82 * v) unplug io to this physical block, including the io that triggered
83 * the breaking of sharing.
84 *
85 * Steps (ii) and (iii) occur in parallel.
86 *
87 * The metadata _doesn't_ need to be committed before the io continues. We
88 * get away with this because the io is always written to a _new_ block.
89 * If there's a crash, then:
90 *
91 * - The origin mapping will point to the old origin block (the shared
92 * one). This will contain the data as it was before the io that triggered
93 * the breaking of sharing came in.
94 *
95 * - The snap mapping still points to the old block. As it would after
96 * the commit.
97 *
98 * The downside of this scheme is the timestamp magic isn't perfect, and
99 * will continue to think that data block in the snapshot device is shared
100 * even after the write to the origin has broken sharing. I suspect data
101 * blocks will typically be shared by many different devices, so we're
102 * breaking sharing n + 1 times, rather than n, where n is the number of
103 * devices that reference this data block. At the moment I think the
104 * benefits far, far outweigh the disadvantages.
105 */
106
107/*----------------------------------------------------------------*/
108
109/*
110 * Sometimes we can't deal with a bio straight away. We put them in prison
111 * where they can't cause any mischief. Bios are put in a cell identified
112 * by a key, multiple bios can be in the same cell. When the cell is
113 * subsequently unlocked the bios become available.
114 */
115struct bio_prison;
116
117struct cell_key {
118 int virtual;
119 dm_thin_id dev;
120 dm_block_t block;
121};
122
123struct cell {
124 struct hlist_node list;
125 struct bio_prison *prison;
126 struct cell_key key;
127 unsigned count;
128 struct bio_list bios;
129};
130
131struct bio_prison {
132 spinlock_t lock;
133 mempool_t *cell_pool;
134
135 unsigned nr_buckets;
136 unsigned hash_mask;
137 struct hlist_head *cells;
138};
139
140static uint32_t calc_nr_buckets(unsigned nr_cells)
141{
142 uint32_t n = 128;
143
144 nr_cells /= 4;
145 nr_cells = min(nr_cells, 8192u);
146
147 while (n < nr_cells)
148 n <<= 1;
149
150 return n;
151}
152
153/*
154 * @nr_cells should be the number of cells you want in use _concurrently_.
155 * Don't confuse it with the number of distinct keys.
156 */
157static struct bio_prison *prison_create(unsigned nr_cells)
158{
159 unsigned i;
160 uint32_t nr_buckets = calc_nr_buckets(nr_cells);
161 size_t len = sizeof(struct bio_prison) +
162 (sizeof(struct hlist_head) * nr_buckets);
163 struct bio_prison *prison = kmalloc(len, GFP_KERNEL);
164
165 if (!prison)
166 return NULL;
167
168 spin_lock_init(&prison->lock);
169 prison->cell_pool = mempool_create_kmalloc_pool(nr_cells,
170 sizeof(struct cell));
171 if (!prison->cell_pool) {
172 kfree(prison);
173 return NULL;
174 }
175
176 prison->nr_buckets = nr_buckets;
177 prison->hash_mask = nr_buckets - 1;
178 prison->cells = (struct hlist_head *) (prison + 1);
179 for (i = 0; i < nr_buckets; i++)
180 INIT_HLIST_HEAD(prison->cells + i);
181
182 return prison;
183}
184
185static void prison_destroy(struct bio_prison *prison)
186{
187 mempool_destroy(prison->cell_pool);
188 kfree(prison);
189}
190
191static uint32_t hash_key(struct bio_prison *prison, struct cell_key *key)
192{
193 const unsigned long BIG_PRIME = 4294967291UL;
194 uint64_t hash = key->block * BIG_PRIME;
195
196 return (uint32_t) (hash & prison->hash_mask);
197}
198
199static int keys_equal(struct cell_key *lhs, struct cell_key *rhs)
200{
201 return (lhs->virtual == rhs->virtual) &&
202 (lhs->dev == rhs->dev) &&
203 (lhs->block == rhs->block);
204}
205
206static struct cell *__search_bucket(struct hlist_head *bucket,
207 struct cell_key *key)
208{
209 struct cell *cell;
210 struct hlist_node *tmp;
211
212 hlist_for_each_entry(cell, tmp, bucket, list)
213 if (keys_equal(&cell->key, key))
214 return cell;
215
216 return NULL;
217}
218
219/*
220 * This may block if a new cell needs allocating. You must ensure that
221 * cells will be unlocked even if the calling thread is blocked.
222 *
223 * Returns the number of entries in the cell prior to the new addition
224 * or < 0 on failure.
225 */
226static int bio_detain(struct bio_prison *prison, struct cell_key *key,
227 struct bio *inmate, struct cell **ref)
228{
229 int r;
230 unsigned long flags;
231 uint32_t hash = hash_key(prison, key);
232 struct cell *uninitialized_var(cell), *cell2 = NULL;
233
234 BUG_ON(hash > prison->nr_buckets);
235
236 spin_lock_irqsave(&prison->lock, flags);
237 cell = __search_bucket(prison->cells + hash, key);
238
239 if (!cell) {
240 /*
241 * Allocate a new cell
242 */
243 spin_unlock_irqrestore(&prison->lock, flags);
244 cell2 = mempool_alloc(prison->cell_pool, GFP_NOIO);
245 spin_lock_irqsave(&prison->lock, flags);
246
247 /*
248 * We've been unlocked, so we have to double check that
249 * nobody else has inserted this cell in the meantime.
250 */
251 cell = __search_bucket(prison->cells + hash, key);
252
253 if (!cell) {
254 cell = cell2;
255 cell2 = NULL;
256
257 cell->prison = prison;
258 memcpy(&cell->key, key, sizeof(cell->key));
259 cell->count = 0;
260 bio_list_init(&cell->bios);
261 hlist_add_head(&cell->list, prison->cells + hash);
262 }
263 }
264
265 r = cell->count++;
266 bio_list_add(&cell->bios, inmate);
267 spin_unlock_irqrestore(&prison->lock, flags);
268
269 if (cell2)
270 mempool_free(cell2, prison->cell_pool);
271
272 *ref = cell;
273
274 return r;
275}
276
277/*
278 * @inmates must have been initialised prior to this call
279 */
280static void __cell_release(struct cell *cell, struct bio_list *inmates)
281{
282 struct bio_prison *prison = cell->prison;
283
284 hlist_del(&cell->list);
285
286 if (inmates)
287 bio_list_merge(inmates, &cell->bios);
288
289 mempool_free(cell, prison->cell_pool);
290}
291
292static void cell_release(struct cell *cell, struct bio_list *bios)
293{
294 unsigned long flags;
295 struct bio_prison *prison = cell->prison;
296
297 spin_lock_irqsave(&prison->lock, flags);
298 __cell_release(cell, bios);
299 spin_unlock_irqrestore(&prison->lock, flags);
300}
301
302/*
303 * There are a couple of places where we put a bio into a cell briefly
304 * before taking it out again. In these situations we know that no other
305 * bio may be in the cell. This function releases the cell, and also does
306 * a sanity check.
307 */
308static void cell_release_singleton(struct cell *cell, struct bio *bio)
309{
310 struct bio_prison *prison = cell->prison;
311 struct bio_list bios;
312 struct bio *b;
313 unsigned long flags;
314
315 bio_list_init(&bios);
316
317 spin_lock_irqsave(&prison->lock, flags);
318 __cell_release(cell, &bios);
319 spin_unlock_irqrestore(&prison->lock, flags);
320
321 b = bio_list_pop(&bios);
322 BUG_ON(b != bio);
323 BUG_ON(!bio_list_empty(&bios));
324}
325
326static void cell_error(struct cell *cell)
327{
328 struct bio_prison *prison = cell->prison;
329 struct bio_list bios;
330 struct bio *bio;
331 unsigned long flags;
332
333 bio_list_init(&bios);
334
335 spin_lock_irqsave(&prison->lock, flags);
336 __cell_release(cell, &bios);
337 spin_unlock_irqrestore(&prison->lock, flags);
338
339 while ((bio = bio_list_pop(&bios)))
340 bio_io_error(bio);
341}
342
343/*----------------------------------------------------------------*/
344
345/*
346 * We use the deferred set to keep track of pending reads to shared blocks.
347 * We do this to ensure the new mapping caused by a write isn't performed
348 * until these prior reads have completed. Otherwise the insertion of the
349 * new mapping could free the old block that the read bios are mapped to.
350 */
351
352struct deferred_set;
353struct deferred_entry {
354 struct deferred_set *ds;
355 unsigned count;
356 struct list_head work_items;
357};
358
359struct deferred_set {
360 spinlock_t lock;
361 unsigned current_entry;
362 unsigned sweeper;
363 struct deferred_entry entries[DEFERRED_SET_SIZE];
364};
365
366static void ds_init(struct deferred_set *ds)
367{
368 int i;
369
370 spin_lock_init(&ds->lock);
371 ds->current_entry = 0;
372 ds->sweeper = 0;
373 for (i = 0; i < DEFERRED_SET_SIZE; i++) {
374 ds->entries[i].ds = ds;
375 ds->entries[i].count = 0;
376 INIT_LIST_HEAD(&ds->entries[i].work_items);
377 }
378}
379
380static struct deferred_entry *ds_inc(struct deferred_set *ds)
381{
382 unsigned long flags;
383 struct deferred_entry *entry;
384
385 spin_lock_irqsave(&ds->lock, flags);
386 entry = ds->entries + ds->current_entry;
387 entry->count++;
388 spin_unlock_irqrestore(&ds->lock, flags);
389
390 return entry;
391}
392
393static unsigned ds_next(unsigned index)
394{
395 return (index + 1) % DEFERRED_SET_SIZE;
396}
397
398static void __sweep(struct deferred_set *ds, struct list_head *head)
399{
400 while ((ds->sweeper != ds->current_entry) &&
401 !ds->entries[ds->sweeper].count) {
402 list_splice_init(&ds->entries[ds->sweeper].work_items, head);
403 ds->sweeper = ds_next(ds->sweeper);
404 }
405
406 if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count)
407 list_splice_init(&ds->entries[ds->sweeper].work_items, head);
408}
409
410static void ds_dec(struct deferred_entry *entry, struct list_head *head)
411{
412 unsigned long flags;
413
414 spin_lock_irqsave(&entry->ds->lock, flags);
415 BUG_ON(!entry->count);
416 --entry->count;
417 __sweep(entry->ds, head);
418 spin_unlock_irqrestore(&entry->ds->lock, flags);
419}
420
421/*
422 * Returns 1 if deferred or 0 if no pending items to delay job.
423 */
424static int ds_add_work(struct deferred_set *ds, struct list_head *work)
425{
426 int r = 1;
427 unsigned long flags;
428 unsigned next_entry;
429
430 spin_lock_irqsave(&ds->lock, flags);
431 if ((ds->sweeper == ds->current_entry) &&
432 !ds->entries[ds->current_entry].count)
433 r = 0;
434 else {
435 list_add(work, &ds->entries[ds->current_entry].work_items);
436 next_entry = ds_next(ds->current_entry);
437 if (!ds->entries[next_entry].count)
438 ds->current_entry = next_entry;
439 }
440 spin_unlock_irqrestore(&ds->lock, flags);
441
442 return r;
443}
444
445/*----------------------------------------------------------------*/
446
447/*
448 * Key building.
449 */
450static void build_data_key(struct dm_thin_device *td,
451 dm_block_t b, struct cell_key *key)
452{
453 key->virtual = 0;
454 key->dev = dm_thin_dev_id(td);
455 key->block = b;
456}
457
458static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
459 struct cell_key *key)
460{
461 key->virtual = 1;
462 key->dev = dm_thin_dev_id(td);
463 key->block = b;
464}
465
466/*----------------------------------------------------------------*/
467
468/*
469 * A pool device ties together a metadata device and a data device. It
470 * also provides the interface for creating and destroying internal
471 * devices.
472 */
473struct new_mapping;
474struct pool {
475 struct list_head list;
476 struct dm_target *ti; /* Only set if a pool target is bound */
477
478 struct mapped_device *pool_md;
479 struct block_device *md_dev;
480 struct dm_pool_metadata *pmd;
481
482 uint32_t sectors_per_block;
483 unsigned block_shift;
484 dm_block_t offset_mask;
485 dm_block_t low_water_blocks;
486
487 unsigned zero_new_blocks:1;
488 unsigned low_water_triggered:1; /* A dm event has been sent */
489 unsigned no_free_space:1; /* A -ENOSPC warning has been issued */
490
491 struct bio_prison *prison;
492 struct dm_kcopyd_client *copier;
493
494 struct workqueue_struct *wq;
495 struct work_struct worker;
496
497 unsigned ref_count;
498
499 spinlock_t lock;
500 struct bio_list deferred_bios;
501 struct bio_list deferred_flush_bios;
502 struct list_head prepared_mappings;
503
504 struct bio_list retry_on_resume_list;
505
506 struct deferred_set ds; /* FIXME: move to thin_c */
507
508 struct new_mapping *next_mapping;
509 mempool_t *mapping_pool;
510 mempool_t *endio_hook_pool;
511};
512
513/*
514 * Target context for a pool.
515 */
516struct pool_c {
517 struct dm_target *ti;
518 struct pool *pool;
519 struct dm_dev *data_dev;
520 struct dm_dev *metadata_dev;
521 struct dm_target_callbacks callbacks;
522
523 dm_block_t low_water_blocks;
524 unsigned zero_new_blocks:1;
525};
526
527/*
528 * Target context for a thin.
529 */
530struct thin_c {
531 struct dm_dev *pool_dev;
532 dm_thin_id dev_id;
533
534 struct pool *pool;
535 struct dm_thin_device *td;
536};
537
538/*----------------------------------------------------------------*/
539
540/*
541 * A global list of pools that uses a struct mapped_device as a key.
542 */
543static struct dm_thin_pool_table {
544 struct mutex mutex;
545 struct list_head pools;
546} dm_thin_pool_table;
547
548static void pool_table_init(void)
549{
550 mutex_init(&dm_thin_pool_table.mutex);
551 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
552}
553
554static void __pool_table_insert(struct pool *pool)
555{
556 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
557 list_add(&pool->list, &dm_thin_pool_table.pools);
558}
559
560static void __pool_table_remove(struct pool *pool)
561{
562 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
563 list_del(&pool->list);
564}
565
566static struct pool *__pool_table_lookup(struct mapped_device *md)
567{
568 struct pool *pool = NULL, *tmp;
569
570 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
571
572 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
573 if (tmp->pool_md == md) {
574 pool = tmp;
575 break;
576 }
577 }
578
579 return pool;
580}
581
582static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
583{
584 struct pool *pool = NULL, *tmp;
585
586 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
587
588 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
589 if (tmp->md_dev == md_dev) {
590 pool = tmp;
591 break;
592 }
593 }
594
595 return pool;
596}
597
598/*----------------------------------------------------------------*/
599
600static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
601{
602 struct bio *bio;
603 struct bio_list bios;
604
605 bio_list_init(&bios);
606 bio_list_merge(&bios, master);
607 bio_list_init(master);
608
609 while ((bio = bio_list_pop(&bios))) {
610 if (dm_get_mapinfo(bio)->ptr == tc)
611 bio_endio(bio, DM_ENDIO_REQUEUE);
612 else
613 bio_list_add(master, bio);
614 }
615}
616
617static void requeue_io(struct thin_c *tc)
618{
619 struct pool *pool = tc->pool;
620 unsigned long flags;
621
622 spin_lock_irqsave(&pool->lock, flags);
623 __requeue_bio_list(tc, &pool->deferred_bios);
624 __requeue_bio_list(tc, &pool->retry_on_resume_list);
625 spin_unlock_irqrestore(&pool->lock, flags);
626}
627
628/*
629 * This section of code contains the logic for processing a thin device's IO.
630 * Much of the code depends on pool object resources (lists, workqueues, etc)
631 * but most is exclusively called from the thin target rather than the thin-pool
632 * target.
633 */
634
635static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
636{
637 return bio->bi_sector >> tc->pool->block_shift;
638}
639
640static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
641{
642 struct pool *pool = tc->pool;
643
644 bio->bi_bdev = tc->pool_dev->bdev;
645 bio->bi_sector = (block << pool->block_shift) +
646 (bio->bi_sector & pool->offset_mask);
647}
648
649static void remap_and_issue(struct thin_c *tc, struct bio *bio,
650 dm_block_t block)
651{
652 struct pool *pool = tc->pool;
653 unsigned long flags;
654
655 remap(tc, bio, block);
656
657 /*
658 * Batch together any FUA/FLUSH bios we find and then issue
659 * a single commit for them in process_deferred_bios().
660 */
661 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
662 spin_lock_irqsave(&pool->lock, flags);
663 bio_list_add(&pool->deferred_flush_bios, bio);
664 spin_unlock_irqrestore(&pool->lock, flags);
665 } else
666 generic_make_request(bio);
667}
668
669/*
670 * wake_worker() is used when new work is queued and when pool_resume is
671 * ready to continue deferred IO processing.
672 */
673static void wake_worker(struct pool *pool)
674{
675 queue_work(pool->wq, &pool->worker);
676}
677
678/*----------------------------------------------------------------*/
679
680/*
681 * Bio endio functions.
682 */
683struct endio_hook {
684 struct thin_c *tc;
685 bio_end_io_t *saved_bi_end_io;
686 struct deferred_entry *entry;
687};
688
689struct new_mapping {
690 struct list_head list;
691
692 int prepared;
693
694 struct thin_c *tc;
695 dm_block_t virt_block;
696 dm_block_t data_block;
697 struct cell *cell;
698 int err;
699
700 /*
701 * If the bio covers the whole area of a block then we can avoid
702 * zeroing or copying. Instead this bio is hooked. The bio will
703 * still be in the cell, so care has to be taken to avoid issuing
704 * the bio twice.
705 */
706 struct bio *bio;
707 bio_end_io_t *saved_bi_end_io;
708};
709
710static void __maybe_add_mapping(struct new_mapping *m)
711{
712 struct pool *pool = m->tc->pool;
713
714 if (list_empty(&m->list) && m->prepared) {
715 list_add(&m->list, &pool->prepared_mappings);
716 wake_worker(pool);
717 }
718}
719
720static void copy_complete(int read_err, unsigned long write_err, void *context)
721{
722 unsigned long flags;
723 struct new_mapping *m = context;
724 struct pool *pool = m->tc->pool;
725
726 m->err = read_err || write_err ? -EIO : 0;
727
728 spin_lock_irqsave(&pool->lock, flags);
729 m->prepared = 1;
730 __maybe_add_mapping(m);
731 spin_unlock_irqrestore(&pool->lock, flags);
732}
733
734static void overwrite_endio(struct bio *bio, int err)
735{
736 unsigned long flags;
737 struct new_mapping *m = dm_get_mapinfo(bio)->ptr;
738 struct pool *pool = m->tc->pool;
739
740 m->err = err;
741
742 spin_lock_irqsave(&pool->lock, flags);
743 m->prepared = 1;
744 __maybe_add_mapping(m);
745 spin_unlock_irqrestore(&pool->lock, flags);
746}
747
748static void shared_read_endio(struct bio *bio, int err)
749{
750 struct list_head mappings;
751 struct new_mapping *m, *tmp;
752 struct endio_hook *h = dm_get_mapinfo(bio)->ptr;
753 unsigned long flags;
754 struct pool *pool = h->tc->pool;
755
756 bio->bi_end_io = h->saved_bi_end_io;
757 bio_endio(bio, err);
758
759 INIT_LIST_HEAD(&mappings);
760 ds_dec(h->entry, &mappings);
761
762 spin_lock_irqsave(&pool->lock, flags);
763 list_for_each_entry_safe(m, tmp, &mappings, list) {
764 list_del(&m->list);
765 INIT_LIST_HEAD(&m->list);
766 __maybe_add_mapping(m);
767 }
768 spin_unlock_irqrestore(&pool->lock, flags);
769
770 mempool_free(h, pool->endio_hook_pool);
771}
772
773/*----------------------------------------------------------------*/
774
775/*
776 * Workqueue.
777 */
778
779/*
780 * Prepared mapping jobs.
781 */
782
783/*
784 * This sends the bios in the cell back to the deferred_bios list.
785 */
786static void cell_defer(struct thin_c *tc, struct cell *cell,
787 dm_block_t data_block)
788{
789 struct pool *pool = tc->pool;
790 unsigned long flags;
791
792 spin_lock_irqsave(&pool->lock, flags);
793 cell_release(cell, &pool->deferred_bios);
794 spin_unlock_irqrestore(&tc->pool->lock, flags);
795
796 wake_worker(pool);
797}
798
799/*
800 * Same as cell_defer above, except it omits one particular detainee,
801 * a write bio that covers the block and has already been processed.
802 */
803static void cell_defer_except(struct thin_c *tc, struct cell *cell,
804 struct bio *exception)
805{
806 struct bio_list bios;
807 struct bio *bio;
808 struct pool *pool = tc->pool;
809 unsigned long flags;
810
811 bio_list_init(&bios);
812 cell_release(cell, &bios);
813
814 spin_lock_irqsave(&pool->lock, flags);
815 while ((bio = bio_list_pop(&bios)))
816 if (bio != exception)
817 bio_list_add(&pool->deferred_bios, bio);
818 spin_unlock_irqrestore(&pool->lock, flags);
819
820 wake_worker(pool);
821}
822
823static void process_prepared_mapping(struct new_mapping *m)
824{
825 struct thin_c *tc = m->tc;
826 struct bio *bio;
827 int r;
828
829 bio = m->bio;
830 if (bio)
831 bio->bi_end_io = m->saved_bi_end_io;
832
833 if (m->err) {
834 cell_error(m->cell);
835 return;
836 }
837
838 /*
839 * Commit the prepared block into the mapping btree.
840 * Any I/O for this block arriving after this point will get
841 * remapped to it directly.
842 */
843 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
844 if (r) {
845 DMERR("dm_thin_insert_block() failed");
846 cell_error(m->cell);
847 return;
848 }
849
850 /*
851 * Release any bios held while the block was being provisioned.
852 * If we are processing a write bio that completely covers the block,
853 * we already processed it so can ignore it now when processing
854 * the bios in the cell.
855 */
856 if (bio) {
857 cell_defer_except(tc, m->cell, bio);
858 bio_endio(bio, 0);
859 } else
860 cell_defer(tc, m->cell, m->data_block);
861
862 list_del(&m->list);
863 mempool_free(m, tc->pool->mapping_pool);
864}
865
866static void process_prepared_mappings(struct pool *pool)
867{
868 unsigned long flags;
869 struct list_head maps;
870 struct new_mapping *m, *tmp;
871
872 INIT_LIST_HEAD(&maps);
873 spin_lock_irqsave(&pool->lock, flags);
874 list_splice_init(&pool->prepared_mappings, &maps);
875 spin_unlock_irqrestore(&pool->lock, flags);
876
877 list_for_each_entry_safe(m, tmp, &maps, list)
878 process_prepared_mapping(m);
879}
880
881/*
882 * Deferred bio jobs.
883 */
884static int io_overwrites_block(struct pool *pool, struct bio *bio)
885{
886 return ((bio_data_dir(bio) == WRITE) &&
887 !(bio->bi_sector & pool->offset_mask)) &&
888 (bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT));
889}
890
891static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
892 bio_end_io_t *fn)
893{
894 *save = bio->bi_end_io;
895 bio->bi_end_io = fn;
896}
897
898static int ensure_next_mapping(struct pool *pool)
899{
900 if (pool->next_mapping)
901 return 0;
902
903 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
904
905 return pool->next_mapping ? 0 : -ENOMEM;
906}
907
908static struct new_mapping *get_next_mapping(struct pool *pool)
909{
910 struct new_mapping *r = pool->next_mapping;
911
912 BUG_ON(!pool->next_mapping);
913
914 pool->next_mapping = NULL;
915
916 return r;
917}
918
919static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
920 dm_block_t data_origin, dm_block_t data_dest,
921 struct cell *cell, struct bio *bio)
922{
923 int r;
924 struct pool *pool = tc->pool;
925 struct new_mapping *m = get_next_mapping(pool);
926
927 INIT_LIST_HEAD(&m->list);
928 m->prepared = 0;
929 m->tc = tc;
930 m->virt_block = virt_block;
931 m->data_block = data_dest;
932 m->cell = cell;
933 m->err = 0;
934 m->bio = NULL;
935
936 ds_add_work(&pool->ds, &m->list);
937
938 /*
939 * IO to pool_dev remaps to the pool target's data_dev.
940 *
941 * If the whole block of data is being overwritten, we can issue the
942 * bio immediately. Otherwise we use kcopyd to clone the data first.
943 */
944 if (io_overwrites_block(pool, bio)) {
945 m->bio = bio;
946 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
947 dm_get_mapinfo(bio)->ptr = m;
948 remap_and_issue(tc, bio, data_dest);
949 } else {
950 struct dm_io_region from, to;
951
952 from.bdev = tc->pool_dev->bdev;
953 from.sector = data_origin * pool->sectors_per_block;
954 from.count = pool->sectors_per_block;
955
956 to.bdev = tc->pool_dev->bdev;
957 to.sector = data_dest * pool->sectors_per_block;
958 to.count = pool->sectors_per_block;
959
960 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
961 0, copy_complete, m);
962 if (r < 0) {
963 mempool_free(m, pool->mapping_pool);
964 DMERR("dm_kcopyd_copy() failed");
965 cell_error(cell);
966 }
967 }
968}
969
970static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
971 dm_block_t data_block, struct cell *cell,
972 struct bio *bio)
973{
974 struct pool *pool = tc->pool;
975 struct new_mapping *m = get_next_mapping(pool);
976
977 INIT_LIST_HEAD(&m->list);
978 m->prepared = 0;
979 m->tc = tc;
980 m->virt_block = virt_block;
981 m->data_block = data_block;
982 m->cell = cell;
983 m->err = 0;
984 m->bio = NULL;
985
986 /*
987 * If the whole block of data is being overwritten or we are not
988 * zeroing pre-existing data, we can issue the bio immediately.
989 * Otherwise we use kcopyd to zero the data first.
990 */
991 if (!pool->zero_new_blocks)
992 process_prepared_mapping(m);
993
994 else if (io_overwrites_block(pool, bio)) {
995 m->bio = bio;
996 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
997 dm_get_mapinfo(bio)->ptr = m;
998 remap_and_issue(tc, bio, data_block);
999
1000 } else {
1001 int r;
1002 struct dm_io_region to;
1003
1004 to.bdev = tc->pool_dev->bdev;
1005 to.sector = data_block * pool->sectors_per_block;
1006 to.count = pool->sectors_per_block;
1007
1008 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
1009 if (r < 0) {
1010 mempool_free(m, pool->mapping_pool);
1011 DMERR("dm_kcopyd_zero() failed");
1012 cell_error(cell);
1013 }
1014 }
1015}
1016
1017static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1018{
1019 int r;
1020 dm_block_t free_blocks;
1021 unsigned long flags;
1022 struct pool *pool = tc->pool;
1023
1024 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1025 if (r)
1026 return r;
1027
1028 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1029 DMWARN("%s: reached low water mark, sending event.",
1030 dm_device_name(pool->pool_md));
1031 spin_lock_irqsave(&pool->lock, flags);
1032 pool->low_water_triggered = 1;
1033 spin_unlock_irqrestore(&pool->lock, flags);
1034 dm_table_event(pool->ti->table);
1035 }
1036
1037 if (!free_blocks) {
1038 if (pool->no_free_space)
1039 return -ENOSPC;
1040 else {
1041 /*
1042 * Try to commit to see if that will free up some
1043 * more space.
1044 */
1045 r = dm_pool_commit_metadata(pool->pmd);
1046 if (r) {
1047 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1048 __func__, r);
1049 return r;
1050 }
1051
1052 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1053 if (r)
1054 return r;
1055
1056 /*
1057 * If we still have no space we set a flag to avoid
1058 * doing all this checking and return -ENOSPC.
1059 */
1060 if (!free_blocks) {
1061 DMWARN("%s: no free space available.",
1062 dm_device_name(pool->pool_md));
1063 spin_lock_irqsave(&pool->lock, flags);
1064 pool->no_free_space = 1;
1065 spin_unlock_irqrestore(&pool->lock, flags);
1066 return -ENOSPC;
1067 }
1068 }
1069 }
1070
1071 r = dm_pool_alloc_data_block(pool->pmd, result);
1072 if (r)
1073 return r;
1074
1075 return 0;
1076}
1077
1078/*
1079 * If we have run out of space, queue bios until the device is
1080 * resumed, presumably after having been reloaded with more space.
1081 */
1082static void retry_on_resume(struct bio *bio)
1083{
1084 struct thin_c *tc = dm_get_mapinfo(bio)->ptr;
1085 struct pool *pool = tc->pool;
1086 unsigned long flags;
1087
1088 spin_lock_irqsave(&pool->lock, flags);
1089 bio_list_add(&pool->retry_on_resume_list, bio);
1090 spin_unlock_irqrestore(&pool->lock, flags);
1091}
1092
1093static void no_space(struct cell *cell)
1094{
1095 struct bio *bio;
1096 struct bio_list bios;
1097
1098 bio_list_init(&bios);
1099 cell_release(cell, &bios);
1100
1101 while ((bio = bio_list_pop(&bios)))
1102 retry_on_resume(bio);
1103}
1104
1105static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1106 struct cell_key *key,
1107 struct dm_thin_lookup_result *lookup_result,
1108 struct cell *cell)
1109{
1110 int r;
1111 dm_block_t data_block;
1112
1113 r = alloc_data_block(tc, &data_block);
1114 switch (r) {
1115 case 0:
1116 schedule_copy(tc, block, lookup_result->block,
1117 data_block, cell, bio);
1118 break;
1119
1120 case -ENOSPC:
1121 no_space(cell);
1122 break;
1123
1124 default:
1125 DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
1126 cell_error(cell);
1127 break;
1128 }
1129}
1130
1131static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1132 dm_block_t block,
1133 struct dm_thin_lookup_result *lookup_result)
1134{
1135 struct cell *cell;
1136 struct pool *pool = tc->pool;
1137 struct cell_key key;
1138
1139 /*
1140 * If cell is already occupied, then sharing is already in the process
1141 * of being broken so we have nothing further to do here.
1142 */
1143 build_data_key(tc->td, lookup_result->block, &key);
1144 if (bio_detain(pool->prison, &key, bio, &cell))
1145 return;
1146
1147 if (bio_data_dir(bio) == WRITE)
1148 break_sharing(tc, bio, block, &key, lookup_result, cell);
1149 else {
1150 struct endio_hook *h;
1151 h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO);
1152
1153 h->tc = tc;
1154 h->entry = ds_inc(&pool->ds);
1155 save_and_set_endio(bio, &h->saved_bi_end_io, shared_read_endio);
1156 dm_get_mapinfo(bio)->ptr = h;
1157
1158 cell_release_singleton(cell, bio);
1159 remap_and_issue(tc, bio, lookup_result->block);
1160 }
1161}
1162
1163static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1164 struct cell *cell)
1165{
1166 int r;
1167 dm_block_t data_block;
1168
1169 /*
1170 * Remap empty bios (flushes) immediately, without provisioning.
1171 */
1172 if (!bio->bi_size) {
1173 cell_release_singleton(cell, bio);
1174 remap_and_issue(tc, bio, 0);
1175 return;
1176 }
1177
1178 /*
1179 * Fill read bios with zeroes and complete them immediately.
1180 */
1181 if (bio_data_dir(bio) == READ) {
1182 zero_fill_bio(bio);
1183 cell_release_singleton(cell, bio);
1184 bio_endio(bio, 0);
1185 return;
1186 }
1187
1188 r = alloc_data_block(tc, &data_block);
1189 switch (r) {
1190 case 0:
1191 schedule_zero(tc, block, data_block, cell, bio);
1192 break;
1193
1194 case -ENOSPC:
1195 no_space(cell);
1196 break;
1197
1198 default:
1199 DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
1200 cell_error(cell);
1201 break;
1202 }
1203}
1204
1205static void process_bio(struct thin_c *tc, struct bio *bio)
1206{
1207 int r;
1208 dm_block_t block = get_bio_block(tc, bio);
1209 struct cell *cell;
1210 struct cell_key key;
1211 struct dm_thin_lookup_result lookup_result;
1212
1213 /*
1214 * If cell is already occupied, then the block is already
1215 * being provisioned so we have nothing further to do here.
1216 */
1217 build_virtual_key(tc->td, block, &key);
1218 if (bio_detain(tc->pool->prison, &key, bio, &cell))
1219 return;
1220
1221 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1222 switch (r) {
1223 case 0:
1224 /*
1225 * We can release this cell now. This thread is the only
1226 * one that puts bios into a cell, and we know there were
1227 * no preceding bios.
1228 */
1229 /*
1230 * TODO: this will probably have to change when discard goes
1231 * back in.
1232 */
1233 cell_release_singleton(cell, bio);
1234
1235 if (lookup_result.shared)
1236 process_shared_bio(tc, bio, block, &lookup_result);
1237 else
1238 remap_and_issue(tc, bio, lookup_result.block);
1239 break;
1240
1241 case -ENODATA:
1242 provision_block(tc, bio, block, cell);
1243 break;
1244
1245 default:
1246 DMERR("dm_thin_find_block() failed, error = %d", r);
1247 bio_io_error(bio);
1248 break;
1249 }
1250}
1251
1252static void process_deferred_bios(struct pool *pool)
1253{
1254 unsigned long flags;
1255 struct bio *bio;
1256 struct bio_list bios;
1257 int r;
1258
1259 bio_list_init(&bios);
1260
1261 spin_lock_irqsave(&pool->lock, flags);
1262 bio_list_merge(&bios, &pool->deferred_bios);
1263 bio_list_init(&pool->deferred_bios);
1264 spin_unlock_irqrestore(&pool->lock, flags);
1265
1266 while ((bio = bio_list_pop(&bios))) {
1267 struct thin_c *tc = dm_get_mapinfo(bio)->ptr;
1268 /*
1269 * If we've got no free new_mapping structs, and processing
1270 * this bio might require one, we pause until there are some
1271 * prepared mappings to process.
1272 */
1273 if (ensure_next_mapping(pool)) {
1274 spin_lock_irqsave(&pool->lock, flags);
1275 bio_list_merge(&pool->deferred_bios, &bios);
1276 spin_unlock_irqrestore(&pool->lock, flags);
1277
1278 break;
1279 }
1280 process_bio(tc, bio);
1281 }
1282
1283 /*
1284 * If there are any deferred flush bios, we must commit
1285 * the metadata before issuing them.
1286 */
1287 bio_list_init(&bios);
1288 spin_lock_irqsave(&pool->lock, flags);
1289 bio_list_merge(&bios, &pool->deferred_flush_bios);
1290 bio_list_init(&pool->deferred_flush_bios);
1291 spin_unlock_irqrestore(&pool->lock, flags);
1292
1293 if (bio_list_empty(&bios))
1294 return;
1295
1296 r = dm_pool_commit_metadata(pool->pmd);
1297 if (r) {
1298 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1299 __func__, r);
1300 while ((bio = bio_list_pop(&bios)))
1301 bio_io_error(bio);
1302 return;
1303 }
1304
1305 while ((bio = bio_list_pop(&bios)))
1306 generic_make_request(bio);
1307}
1308
1309static void do_worker(struct work_struct *ws)
1310{
1311 struct pool *pool = container_of(ws, struct pool, worker);
1312
1313 process_prepared_mappings(pool);
1314 process_deferred_bios(pool);
1315}
1316
1317/*----------------------------------------------------------------*/
1318
1319/*
1320 * Mapping functions.
1321 */
1322
1323/*
1324 * Called only while mapping a thin bio to hand it over to the workqueue.
1325 */
1326static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1327{
1328 unsigned long flags;
1329 struct pool *pool = tc->pool;
1330
1331 spin_lock_irqsave(&pool->lock, flags);
1332 bio_list_add(&pool->deferred_bios, bio);
1333 spin_unlock_irqrestore(&pool->lock, flags);
1334
1335 wake_worker(pool);
1336}
1337
1338/*
1339 * Non-blocking function called from the thin target's map function.
1340 */
1341static int thin_bio_map(struct dm_target *ti, struct bio *bio,
1342 union map_info *map_context)
1343{
1344 int r;
1345 struct thin_c *tc = ti->private;
1346 dm_block_t block = get_bio_block(tc, bio);
1347 struct dm_thin_device *td = tc->td;
1348 struct dm_thin_lookup_result result;
1349
1350 /*
1351 * Save the thin context for easy access from the deferred bio later.
1352 */
1353 map_context->ptr = tc;
1354
1355 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
1356 thin_defer_bio(tc, bio);
1357 return DM_MAPIO_SUBMITTED;
1358 }
1359
1360 r = dm_thin_find_block(td, block, 0, &result);
1361
1362 /*
1363 * Note that we defer readahead too.
1364 */
1365 switch (r) {
1366 case 0:
1367 if (unlikely(result.shared)) {
1368 /*
1369 * We have a race condition here between the
1370 * result.shared value returned by the lookup and
1371 * snapshot creation, which may cause new
1372 * sharing.
1373 *
1374 * To avoid this always quiesce the origin before
1375 * taking the snap. You want to do this anyway to
1376 * ensure a consistent application view
1377 * (i.e. lockfs).
1378 *
1379 * More distant ancestors are irrelevant. The
1380 * shared flag will be set in their case.
1381 */
1382 thin_defer_bio(tc, bio);
1383 r = DM_MAPIO_SUBMITTED;
1384 } else {
1385 remap(tc, bio, result.block);
1386 r = DM_MAPIO_REMAPPED;
1387 }
1388 break;
1389
1390 case -ENODATA:
1391 /*
1392 * In future, the failed dm_thin_find_block above could
1393 * provide the hint to load the metadata into cache.
1394 */
1395 case -EWOULDBLOCK:
1396 thin_defer_bio(tc, bio);
1397 r = DM_MAPIO_SUBMITTED;
1398 break;
1399 }
1400
1401 return r;
1402}
1403
1404static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1405{
1406 int r;
1407 unsigned long flags;
1408 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1409
1410 spin_lock_irqsave(&pt->pool->lock, flags);
1411 r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1412 spin_unlock_irqrestore(&pt->pool->lock, flags);
1413
1414 if (!r) {
1415 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1416 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1417 }
1418
1419 return r;
1420}
1421
1422static void __requeue_bios(struct pool *pool)
1423{
1424 bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1425 bio_list_init(&pool->retry_on_resume_list);
1426}
1427
1428/*----------------------------------------------------------------
1429 * Binding of control targets to a pool object
1430 *--------------------------------------------------------------*/
1431static int bind_control_target(struct pool *pool, struct dm_target *ti)
1432{
1433 struct pool_c *pt = ti->private;
1434
1435 pool->ti = ti;
1436 pool->low_water_blocks = pt->low_water_blocks;
1437 pool->zero_new_blocks = pt->zero_new_blocks;
1438
1439 return 0;
1440}
1441
1442static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1443{
1444 if (pool->ti == ti)
1445 pool->ti = NULL;
1446}
1447
1448/*----------------------------------------------------------------
1449 * Pool creation
1450 *--------------------------------------------------------------*/
1451static void __pool_destroy(struct pool *pool)
1452{
1453 __pool_table_remove(pool);
1454
1455 if (dm_pool_metadata_close(pool->pmd) < 0)
1456 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1457
1458 prison_destroy(pool->prison);
1459 dm_kcopyd_client_destroy(pool->copier);
1460
1461 if (pool->wq)
1462 destroy_workqueue(pool->wq);
1463
1464 if (pool->next_mapping)
1465 mempool_free(pool->next_mapping, pool->mapping_pool);
1466 mempool_destroy(pool->mapping_pool);
1467 mempool_destroy(pool->endio_hook_pool);
1468 kfree(pool);
1469}
1470
1471static struct pool *pool_create(struct mapped_device *pool_md,
1472 struct block_device *metadata_dev,
1473 unsigned long block_size, char **error)
1474{
1475 int r;
1476 void *err_p;
1477 struct pool *pool;
1478 struct dm_pool_metadata *pmd;
1479
1480 pmd = dm_pool_metadata_open(metadata_dev, block_size);
1481 if (IS_ERR(pmd)) {
1482 *error = "Error creating metadata object";
1483 return (struct pool *)pmd;
1484 }
1485
1486 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1487 if (!pool) {
1488 *error = "Error allocating memory for pool";
1489 err_p = ERR_PTR(-ENOMEM);
1490 goto bad_pool;
1491 }
1492
1493 pool->pmd = pmd;
1494 pool->sectors_per_block = block_size;
1495 pool->block_shift = ffs(block_size) - 1;
1496 pool->offset_mask = block_size - 1;
1497 pool->low_water_blocks = 0;
1498 pool->zero_new_blocks = 1;
1499 pool->prison = prison_create(PRISON_CELLS);
1500 if (!pool->prison) {
1501 *error = "Error creating pool's bio prison";
1502 err_p = ERR_PTR(-ENOMEM);
1503 goto bad_prison;
1504 }
1505
1506 pool->copier = dm_kcopyd_client_create();
1507 if (IS_ERR(pool->copier)) {
1508 r = PTR_ERR(pool->copier);
1509 *error = "Error creating pool's kcopyd client";
1510 err_p = ERR_PTR(r);
1511 goto bad_kcopyd_client;
1512 }
1513
1514 /*
1515 * Create singlethreaded workqueue that will service all devices
1516 * that use this metadata.
1517 */
1518 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1519 if (!pool->wq) {
1520 *error = "Error creating pool's workqueue";
1521 err_p = ERR_PTR(-ENOMEM);
1522 goto bad_wq;
1523 }
1524
1525 INIT_WORK(&pool->worker, do_worker);
1526 spin_lock_init(&pool->lock);
1527 bio_list_init(&pool->deferred_bios);
1528 bio_list_init(&pool->deferred_flush_bios);
1529 INIT_LIST_HEAD(&pool->prepared_mappings);
1530 pool->low_water_triggered = 0;
1531 pool->no_free_space = 0;
1532 bio_list_init(&pool->retry_on_resume_list);
1533 ds_init(&pool->ds);
1534
1535 pool->next_mapping = NULL;
1536 pool->mapping_pool =
1537 mempool_create_kmalloc_pool(MAPPING_POOL_SIZE, sizeof(struct new_mapping));
1538 if (!pool->mapping_pool) {
1539 *error = "Error creating pool's mapping mempool";
1540 err_p = ERR_PTR(-ENOMEM);
1541 goto bad_mapping_pool;
1542 }
1543
1544 pool->endio_hook_pool =
1545 mempool_create_kmalloc_pool(ENDIO_HOOK_POOL_SIZE, sizeof(struct endio_hook));
1546 if (!pool->endio_hook_pool) {
1547 *error = "Error creating pool's endio_hook mempool";
1548 err_p = ERR_PTR(-ENOMEM);
1549 goto bad_endio_hook_pool;
1550 }
1551 pool->ref_count = 1;
1552 pool->pool_md = pool_md;
1553 pool->md_dev = metadata_dev;
1554 __pool_table_insert(pool);
1555
1556 return pool;
1557
1558bad_endio_hook_pool:
1559 mempool_destroy(pool->mapping_pool);
1560bad_mapping_pool:
1561 destroy_workqueue(pool->wq);
1562bad_wq:
1563 dm_kcopyd_client_destroy(pool->copier);
1564bad_kcopyd_client:
1565 prison_destroy(pool->prison);
1566bad_prison:
1567 kfree(pool);
1568bad_pool:
1569 if (dm_pool_metadata_close(pmd))
1570 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1571
1572 return err_p;
1573}
1574
1575static void __pool_inc(struct pool *pool)
1576{
1577 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1578 pool->ref_count++;
1579}
1580
1581static void __pool_dec(struct pool *pool)
1582{
1583 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1584 BUG_ON(!pool->ref_count);
1585 if (!--pool->ref_count)
1586 __pool_destroy(pool);
1587}
1588
1589static struct pool *__pool_find(struct mapped_device *pool_md,
1590 struct block_device *metadata_dev,
1591 unsigned long block_size, char **error)
1592{
1593 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1594
1595 if (pool) {
1596 if (pool->pool_md != pool_md)
1597 return ERR_PTR(-EBUSY);
1598 __pool_inc(pool);
1599
1600 } else {
1601 pool = __pool_table_lookup(pool_md);
1602 if (pool) {
1603 if (pool->md_dev != metadata_dev)
1604 return ERR_PTR(-EINVAL);
1605 __pool_inc(pool);
1606
1607 } else
1608 pool = pool_create(pool_md, metadata_dev, block_size, error);
1609 }
1610
1611 return pool;
1612}
1613
1614/*----------------------------------------------------------------
1615 * Pool target methods
1616 *--------------------------------------------------------------*/
1617static void pool_dtr(struct dm_target *ti)
1618{
1619 struct pool_c *pt = ti->private;
1620
1621 mutex_lock(&dm_thin_pool_table.mutex);
1622
1623 unbind_control_target(pt->pool, ti);
1624 __pool_dec(pt->pool);
1625 dm_put_device(ti, pt->metadata_dev);
1626 dm_put_device(ti, pt->data_dev);
1627 kfree(pt);
1628
1629 mutex_unlock(&dm_thin_pool_table.mutex);
1630}
1631
1632struct pool_features {
1633 unsigned zero_new_blocks:1;
1634};
1635
1636static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
1637 struct dm_target *ti)
1638{
1639 int r;
1640 unsigned argc;
1641 const char *arg_name;
1642
1643 static struct dm_arg _args[] = {
1644 {0, 1, "Invalid number of pool feature arguments"},
1645 };
1646
1647 /*
1648 * No feature arguments supplied.
1649 */
1650 if (!as->argc)
1651 return 0;
1652
1653 r = dm_read_arg_group(_args, as, &argc, &ti->error);
1654 if (r)
1655 return -EINVAL;
1656
1657 while (argc && !r) {
1658 arg_name = dm_shift_arg(as);
1659 argc--;
1660
1661 if (!strcasecmp(arg_name, "skip_block_zeroing")) {
1662 pf->zero_new_blocks = 0;
1663 continue;
1664 }
1665
1666 ti->error = "Unrecognised pool feature requested";
1667 r = -EINVAL;
1668 }
1669
1670 return r;
1671}
1672
1673/*
1674 * thin-pool <metadata dev> <data dev>
1675 * <data block size (sectors)>
1676 * <low water mark (blocks)>
1677 * [<#feature args> [<arg>]*]
1678 *
1679 * Optional feature arguments are:
1680 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1681 */
1682static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
1683{
1684 int r;
1685 struct pool_c *pt;
1686 struct pool *pool;
1687 struct pool_features pf;
1688 struct dm_arg_set as;
1689 struct dm_dev *data_dev;
1690 unsigned long block_size;
1691 dm_block_t low_water_blocks;
1692 struct dm_dev *metadata_dev;
1693 sector_t metadata_dev_size;
1694
1695 /*
1696 * FIXME Remove validation from scope of lock.
1697 */
1698 mutex_lock(&dm_thin_pool_table.mutex);
1699
1700 if (argc < 4) {
1701 ti->error = "Invalid argument count";
1702 r = -EINVAL;
1703 goto out_unlock;
1704 }
1705 as.argc = argc;
1706 as.argv = argv;
1707
1708 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev);
1709 if (r) {
1710 ti->error = "Error opening metadata block device";
1711 goto out_unlock;
1712 }
1713
1714 metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT;
1715 if (metadata_dev_size > METADATA_DEV_MAX_SECTORS) {
1716 ti->error = "Metadata device is too large";
1717 r = -EINVAL;
1718 goto out_metadata;
1719 }
1720
1721 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
1722 if (r) {
1723 ti->error = "Error getting data device";
1724 goto out_metadata;
1725 }
1726
1727 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
1728 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
1729 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
1730 !is_power_of_2(block_size)) {
1731 ti->error = "Invalid block size";
1732 r = -EINVAL;
1733 goto out;
1734 }
1735
1736 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
1737 ti->error = "Invalid low water mark";
1738 r = -EINVAL;
1739 goto out;
1740 }
1741
1742 /*
1743 * Set default pool features.
1744 */
1745 memset(&pf, 0, sizeof(pf));
1746 pf.zero_new_blocks = 1;
1747
1748 dm_consume_args(&as, 4);
1749 r = parse_pool_features(&as, &pf, ti);
1750 if (r)
1751 goto out;
1752
1753 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
1754 if (!pt) {
1755 r = -ENOMEM;
1756 goto out;
1757 }
1758
1759 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
1760 block_size, &ti->error);
1761 if (IS_ERR(pool)) {
1762 r = PTR_ERR(pool);
1763 goto out_free_pt;
1764 }
1765
1766 pt->pool = pool;
1767 pt->ti = ti;
1768 pt->metadata_dev = metadata_dev;
1769 pt->data_dev = data_dev;
1770 pt->low_water_blocks = low_water_blocks;
1771 pt->zero_new_blocks = pf.zero_new_blocks;
1772 ti->num_flush_requests = 1;
1773 ti->num_discard_requests = 0;
1774 ti->private = pt;
1775
1776 pt->callbacks.congested_fn = pool_is_congested;
1777 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
1778
1779 mutex_unlock(&dm_thin_pool_table.mutex);
1780
1781 return 0;
1782
1783out_free_pt:
1784 kfree(pt);
1785out:
1786 dm_put_device(ti, data_dev);
1787out_metadata:
1788 dm_put_device(ti, metadata_dev);
1789out_unlock:
1790 mutex_unlock(&dm_thin_pool_table.mutex);
1791
1792 return r;
1793}
1794
1795static int pool_map(struct dm_target *ti, struct bio *bio,
1796 union map_info *map_context)
1797{
1798 int r;
1799 struct pool_c *pt = ti->private;
1800 struct pool *pool = pt->pool;
1801 unsigned long flags;
1802
1803 /*
1804 * As this is a singleton target, ti->begin is always zero.
1805 */
1806 spin_lock_irqsave(&pool->lock, flags);
1807 bio->bi_bdev = pt->data_dev->bdev;
1808 r = DM_MAPIO_REMAPPED;
1809 spin_unlock_irqrestore(&pool->lock, flags);
1810
1811 return r;
1812}
1813
1814/*
1815 * Retrieves the number of blocks of the data device from
1816 * the superblock and compares it to the actual device size,
1817 * thus resizing the data device in case it has grown.
1818 *
1819 * This both copes with opening preallocated data devices in the ctr
1820 * being followed by a resume
1821 * -and-
1822 * calling the resume method individually after userspace has
1823 * grown the data device in reaction to a table event.
1824 */
1825static int pool_preresume(struct dm_target *ti)
1826{
1827 int r;
1828 struct pool_c *pt = ti->private;
1829 struct pool *pool = pt->pool;
1830 dm_block_t data_size, sb_data_size;
1831
1832 /*
1833 * Take control of the pool object.
1834 */
1835 r = bind_control_target(pool, ti);
1836 if (r)
1837 return r;
1838
1839 data_size = ti->len >> pool->block_shift;
1840 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
1841 if (r) {
1842 DMERR("failed to retrieve data device size");
1843 return r;
1844 }
1845
1846 if (data_size < sb_data_size) {
1847 DMERR("pool target too small, is %llu blocks (expected %llu)",
1848 data_size, sb_data_size);
1849 return -EINVAL;
1850
1851 } else if (data_size > sb_data_size) {
1852 r = dm_pool_resize_data_dev(pool->pmd, data_size);
1853 if (r) {
1854 DMERR("failed to resize data device");
1855 return r;
1856 }
1857
1858 r = dm_pool_commit_metadata(pool->pmd);
1859 if (r) {
1860 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1861 __func__, r);
1862 return r;
1863 }
1864 }
1865
1866 return 0;
1867}
1868
1869static void pool_resume(struct dm_target *ti)
1870{
1871 struct pool_c *pt = ti->private;
1872 struct pool *pool = pt->pool;
1873 unsigned long flags;
1874
1875 spin_lock_irqsave(&pool->lock, flags);
1876 pool->low_water_triggered = 0;
1877 pool->no_free_space = 0;
1878 __requeue_bios(pool);
1879 spin_unlock_irqrestore(&pool->lock, flags);
1880
1881 wake_worker(pool);
1882}
1883
1884static void pool_postsuspend(struct dm_target *ti)
1885{
1886 int r;
1887 struct pool_c *pt = ti->private;
1888 struct pool *pool = pt->pool;
1889
1890 flush_workqueue(pool->wq);
1891
1892 r = dm_pool_commit_metadata(pool->pmd);
1893 if (r < 0) {
1894 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1895 __func__, r);
1896 /* FIXME: invalidate device? error the next FUA or FLUSH bio ?*/
1897 }
1898}
1899
1900static int check_arg_count(unsigned argc, unsigned args_required)
1901{
1902 if (argc != args_required) {
1903 DMWARN("Message received with %u arguments instead of %u.",
1904 argc, args_required);
1905 return -EINVAL;
1906 }
1907
1908 return 0;
1909}
1910
1911static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
1912{
1913 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
1914 *dev_id <= MAX_DEV_ID)
1915 return 0;
1916
1917 if (warning)
1918 DMWARN("Message received with invalid device id: %s", arg);
1919
1920 return -EINVAL;
1921}
1922
1923static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
1924{
1925 dm_thin_id dev_id;
1926 int r;
1927
1928 r = check_arg_count(argc, 2);
1929 if (r)
1930 return r;
1931
1932 r = read_dev_id(argv[1], &dev_id, 1);
1933 if (r)
1934 return r;
1935
1936 r = dm_pool_create_thin(pool->pmd, dev_id);
1937 if (r) {
1938 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
1939 argv[1]);
1940 return r;
1941 }
1942
1943 return 0;
1944}
1945
1946static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
1947{
1948 dm_thin_id dev_id;
1949 dm_thin_id origin_dev_id;
1950 int r;
1951
1952 r = check_arg_count(argc, 3);
1953 if (r)
1954 return r;
1955
1956 r = read_dev_id(argv[1], &dev_id, 1);
1957 if (r)
1958 return r;
1959
1960 r = read_dev_id(argv[2], &origin_dev_id, 1);
1961 if (r)
1962 return r;
1963
1964 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
1965 if (r) {
1966 DMWARN("Creation of new snapshot %s of device %s failed.",
1967 argv[1], argv[2]);
1968 return r;
1969 }
1970
1971 return 0;
1972}
1973
1974static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
1975{
1976 dm_thin_id dev_id;
1977 int r;
1978
1979 r = check_arg_count(argc, 2);
1980 if (r)
1981 return r;
1982
1983 r = read_dev_id(argv[1], &dev_id, 1);
1984 if (r)
1985 return r;
1986
1987 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
1988 if (r)
1989 DMWARN("Deletion of thin device %s failed.", argv[1]);
1990
1991 return r;
1992}
1993
1994static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
1995{
1996 dm_thin_id old_id, new_id;
1997 int r;
1998
1999 r = check_arg_count(argc, 3);
2000 if (r)
2001 return r;
2002
2003 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2004 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2005 return -EINVAL;
2006 }
2007
2008 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2009 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2010 return -EINVAL;
2011 }
2012
2013 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2014 if (r) {
2015 DMWARN("Failed to change transaction id from %s to %s.",
2016 argv[1], argv[2]);
2017 return r;
2018 }
2019
2020 return 0;
2021}
2022
2023/*
2024 * Messages supported:
2025 * create_thin <dev_id>
2026 * create_snap <dev_id> <origin_id>
2027 * delete <dev_id>
2028 * trim <dev_id> <new_size_in_sectors>
2029 * set_transaction_id <current_trans_id> <new_trans_id>
2030 */
2031static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2032{
2033 int r = -EINVAL;
2034 struct pool_c *pt = ti->private;
2035 struct pool *pool = pt->pool;
2036
2037 if (!strcasecmp(argv[0], "create_thin"))
2038 r = process_create_thin_mesg(argc, argv, pool);
2039
2040 else if (!strcasecmp(argv[0], "create_snap"))
2041 r = process_create_snap_mesg(argc, argv, pool);
2042
2043 else if (!strcasecmp(argv[0], "delete"))
2044 r = process_delete_mesg(argc, argv, pool);
2045
2046 else if (!strcasecmp(argv[0], "set_transaction_id"))
2047 r = process_set_transaction_id_mesg(argc, argv, pool);
2048
2049 else
2050 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2051
2052 if (!r) {
2053 r = dm_pool_commit_metadata(pool->pmd);
2054 if (r)
2055 DMERR("%s message: dm_pool_commit_metadata() failed, error = %d",
2056 argv[0], r);
2057 }
2058
2059 return r;
2060}
2061
2062/*
2063 * Status line is:
2064 * <transaction id> <used metadata sectors>/<total metadata sectors>
2065 * <used data sectors>/<total data sectors> <held metadata root>
2066 */
2067static int pool_status(struct dm_target *ti, status_type_t type,
2068 char *result, unsigned maxlen)
2069{
2070 int r;
2071 unsigned sz = 0;
2072 uint64_t transaction_id;
2073 dm_block_t nr_free_blocks_data;
2074 dm_block_t nr_free_blocks_metadata;
2075 dm_block_t nr_blocks_data;
2076 dm_block_t nr_blocks_metadata;
2077 dm_block_t held_root;
2078 char buf[BDEVNAME_SIZE];
2079 char buf2[BDEVNAME_SIZE];
2080 struct pool_c *pt = ti->private;
2081 struct pool *pool = pt->pool;
2082
2083 switch (type) {
2084 case STATUSTYPE_INFO:
2085 r = dm_pool_get_metadata_transaction_id(pool->pmd,
2086 &transaction_id);
2087 if (r)
2088 return r;
2089
2090 r = dm_pool_get_free_metadata_block_count(pool->pmd,
2091 &nr_free_blocks_metadata);
2092 if (r)
2093 return r;
2094
2095 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2096 if (r)
2097 return r;
2098
2099 r = dm_pool_get_free_block_count(pool->pmd,
2100 &nr_free_blocks_data);
2101 if (r)
2102 return r;
2103
2104 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2105 if (r)
2106 return r;
2107
2108 r = dm_pool_get_held_metadata_root(pool->pmd, &held_root);
2109 if (r)
2110 return r;
2111
2112 DMEMIT("%llu %llu/%llu %llu/%llu ",
2113 (unsigned long long)transaction_id,
2114 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2115 (unsigned long long)nr_blocks_metadata,
2116 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2117 (unsigned long long)nr_blocks_data);
2118
2119 if (held_root)
2120 DMEMIT("%llu", held_root);
2121 else
2122 DMEMIT("-");
2123
2124 break;
2125
2126 case STATUSTYPE_TABLE:
2127 DMEMIT("%s %s %lu %llu ",
2128 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2129 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2130 (unsigned long)pool->sectors_per_block,
2131 (unsigned long long)pt->low_water_blocks);
2132
2133 DMEMIT("%u ", !pool->zero_new_blocks);
2134
2135 if (!pool->zero_new_blocks)
2136 DMEMIT("skip_block_zeroing ");
2137 break;
2138 }
2139
2140 return 0;
2141}
2142
2143static int pool_iterate_devices(struct dm_target *ti,
2144 iterate_devices_callout_fn fn, void *data)
2145{
2146 struct pool_c *pt = ti->private;
2147
2148 return fn(ti, pt->data_dev, 0, ti->len, data);
2149}
2150
2151static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2152 struct bio_vec *biovec, int max_size)
2153{
2154 struct pool_c *pt = ti->private;
2155 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2156
2157 if (!q->merge_bvec_fn)
2158 return max_size;
2159
2160 bvm->bi_bdev = pt->data_dev->bdev;
2161
2162 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2163}
2164
2165static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2166{
2167 struct pool_c *pt = ti->private;
2168 struct pool *pool = pt->pool;
2169
2170 blk_limits_io_min(limits, 0);
2171 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2172}
2173
2174static struct target_type pool_target = {
2175 .name = "thin-pool",
2176 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2177 DM_TARGET_IMMUTABLE,
2178 .version = {1, 0, 0},
2179 .module = THIS_MODULE,
2180 .ctr = pool_ctr,
2181 .dtr = pool_dtr,
2182 .map = pool_map,
2183 .postsuspend = pool_postsuspend,
2184 .preresume = pool_preresume,
2185 .resume = pool_resume,
2186 .message = pool_message,
2187 .status = pool_status,
2188 .merge = pool_merge,
2189 .iterate_devices = pool_iterate_devices,
2190 .io_hints = pool_io_hints,
2191};
2192
2193/*----------------------------------------------------------------
2194 * Thin target methods
2195 *--------------------------------------------------------------*/
2196static void thin_dtr(struct dm_target *ti)
2197{
2198 struct thin_c *tc = ti->private;
2199
2200 mutex_lock(&dm_thin_pool_table.mutex);
2201
2202 __pool_dec(tc->pool);
2203 dm_pool_close_thin_device(tc->td);
2204 dm_put_device(ti, tc->pool_dev);
2205 kfree(tc);
2206
2207 mutex_unlock(&dm_thin_pool_table.mutex);
2208}
2209
2210/*
2211 * Thin target parameters:
2212 *
2213 * <pool_dev> <dev_id>
2214 *
2215 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2216 * dev_id: the internal device identifier
2217 */
2218static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2219{
2220 int r;
2221 struct thin_c *tc;
2222 struct dm_dev *pool_dev;
2223 struct mapped_device *pool_md;
2224
2225 mutex_lock(&dm_thin_pool_table.mutex);
2226
2227 if (argc != 2) {
2228 ti->error = "Invalid argument count";
2229 r = -EINVAL;
2230 goto out_unlock;
2231 }
2232
2233 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2234 if (!tc) {
2235 ti->error = "Out of memory";
2236 r = -ENOMEM;
2237 goto out_unlock;
2238 }
2239
2240 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2241 if (r) {
2242 ti->error = "Error opening pool device";
2243 goto bad_pool_dev;
2244 }
2245 tc->pool_dev = pool_dev;
2246
2247 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2248 ti->error = "Invalid device id";
2249 r = -EINVAL;
2250 goto bad_common;
2251 }
2252
2253 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2254 if (!pool_md) {
2255 ti->error = "Couldn't get pool mapped device";
2256 r = -EINVAL;
2257 goto bad_common;
2258 }
2259
2260 tc->pool = __pool_table_lookup(pool_md);
2261 if (!tc->pool) {
2262 ti->error = "Couldn't find pool object";
2263 r = -EINVAL;
2264 goto bad_pool_lookup;
2265 }
2266 __pool_inc(tc->pool);
2267
2268 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
2269 if (r) {
2270 ti->error = "Couldn't open thin internal device";
2271 goto bad_thin_open;
2272 }
2273
2274 ti->split_io = tc->pool->sectors_per_block;
2275 ti->num_flush_requests = 1;
2276 ti->num_discard_requests = 0;
2277 ti->discards_supported = 0;
2278
2279 dm_put(pool_md);
2280
2281 mutex_unlock(&dm_thin_pool_table.mutex);
2282
2283 return 0;
2284
2285bad_thin_open:
2286 __pool_dec(tc->pool);
2287bad_pool_lookup:
2288 dm_put(pool_md);
2289bad_common:
2290 dm_put_device(ti, tc->pool_dev);
2291bad_pool_dev:
2292 kfree(tc);
2293out_unlock:
2294 mutex_unlock(&dm_thin_pool_table.mutex);
2295
2296 return r;
2297}
2298
2299static int thin_map(struct dm_target *ti, struct bio *bio,
2300 union map_info *map_context)
2301{
2302 bio->bi_sector -= ti->begin;
2303
2304 return thin_bio_map(ti, bio, map_context);
2305}
2306
2307static void thin_postsuspend(struct dm_target *ti)
2308{
2309 if (dm_noflush_suspending(ti))
2310 requeue_io((struct thin_c *)ti->private);
2311}
2312
2313/*
2314 * <nr mapped sectors> <highest mapped sector>
2315 */
2316static int thin_status(struct dm_target *ti, status_type_t type,
2317 char *result, unsigned maxlen)
2318{
2319 int r;
2320 ssize_t sz = 0;
2321 dm_block_t mapped, highest;
2322 char buf[BDEVNAME_SIZE];
2323 struct thin_c *tc = ti->private;
2324
2325 if (!tc->td)
2326 DMEMIT("-");
2327 else {
2328 switch (type) {
2329 case STATUSTYPE_INFO:
2330 r = dm_thin_get_mapped_count(tc->td, &mapped);
2331 if (r)
2332 return r;
2333
2334 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
2335 if (r < 0)
2336 return r;
2337
2338 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
2339 if (r)
2340 DMEMIT("%llu", ((highest + 1) *
2341 tc->pool->sectors_per_block) - 1);
2342 else
2343 DMEMIT("-");
2344 break;
2345
2346 case STATUSTYPE_TABLE:
2347 DMEMIT("%s %lu",
2348 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
2349 (unsigned long) tc->dev_id);
2350 break;
2351 }
2352 }
2353
2354 return 0;
2355}
2356
2357static int thin_iterate_devices(struct dm_target *ti,
2358 iterate_devices_callout_fn fn, void *data)
2359{
2360 dm_block_t blocks;
2361 struct thin_c *tc = ti->private;
2362
2363 /*
2364 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2365 * we follow a more convoluted path through to the pool's target.
2366 */
2367 if (!tc->pool->ti)
2368 return 0; /* nothing is bound */
2369
2370 blocks = tc->pool->ti->len >> tc->pool->block_shift;
2371 if (blocks)
2372 return fn(ti, tc->pool_dev, 0, tc->pool->sectors_per_block * blocks, data);
2373
2374 return 0;
2375}
2376
2377static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
2378{
2379 struct thin_c *tc = ti->private;
2380
2381 blk_limits_io_min(limits, 0);
2382 blk_limits_io_opt(limits, tc->pool->sectors_per_block << SECTOR_SHIFT);
2383}
2384
2385static struct target_type thin_target = {
2386 .name = "thin",
2387 .version = {1, 0, 0},
2388 .module = THIS_MODULE,
2389 .ctr = thin_ctr,
2390 .dtr = thin_dtr,
2391 .map = thin_map,
2392 .postsuspend = thin_postsuspend,
2393 .status = thin_status,
2394 .iterate_devices = thin_iterate_devices,
2395 .io_hints = thin_io_hints,
2396};
2397
2398/*----------------------------------------------------------------*/
2399
2400static int __init dm_thin_init(void)
2401{
2402 int r;
2403
2404 pool_table_init();
2405
2406 r = dm_register_target(&thin_target);
2407 if (r)
2408 return r;
2409
2410 r = dm_register_target(&pool_target);
2411 if (r)
2412 dm_unregister_target(&thin_target);
2413
2414 return r;
2415}
2416
2417static void dm_thin_exit(void)
2418{
2419 dm_unregister_target(&thin_target);
2420 dm_unregister_target(&pool_target);
2421}
2422
2423module_init(dm_thin_init);
2424module_exit(dm_thin_exit);
2425
2426MODULE_DESCRIPTION(DM_NAME "device-mapper thin provisioning target");
2427MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2428MODULE_LICENSE("GPL");