2 * Copyright (C) 2011-2012 Red Hat UK.
4 * This file is released under the GPL.
7 #include "dm-thin-metadata.h"
8 #include "dm-bio-prison.h"
11 #include <linux/device-mapper.h>
12 #include <linux/dm-io.h>
13 #include <linux/dm-kcopyd.h>
14 #include <linux/list.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
19 #define DM_MSG_PREFIX "thin"
24 #define ENDIO_HOOK_POOL_SIZE 1024
25 #define MAPPING_POOL_SIZE 1024
26 #define PRISON_CELLS 1024
27 #define COMMIT_PERIOD HZ
29 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
30 "A percentage of time allocated for copy on write");
33 * The block size of the device holding pool data must be
34 * between 64KB and 1GB.
36 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
37 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
40 * Device id is restricted to 24 bits.
42 #define MAX_DEV_ID ((1 << 24) - 1)
45 * How do we handle breaking sharing of data blocks?
46 * =================================================
48 * We use a standard copy-on-write btree to store the mappings for the
49 * devices (note I'm talking about copy-on-write of the metadata here, not
50 * the data). When you take an internal snapshot you clone the root node
51 * of the origin btree. After this there is no concept of an origin or a
52 * snapshot. They are just two device trees that happen to point to the
55 * When we get a write in we decide if it's to a shared data block using
56 * some timestamp magic. If it is, we have to break sharing.
58 * Let's say we write to a shared block in what was the origin. The
61 * i) plug io further to this physical block. (see bio_prison code).
63 * ii) quiesce any read io to that shared data block. Obviously
64 * including all devices that share this block. (see dm_deferred_set code)
66 * iii) copy the data block to a newly allocate block. This step can be
67 * missed out if the io covers the block. (schedule_copy).
69 * iv) insert the new mapping into the origin's btree
70 * (process_prepared_mapping). This act of inserting breaks some
71 * sharing of btree nodes between the two devices. Breaking sharing only
72 * effects the btree of that specific device. Btrees for the other
73 * devices that share the block never change. The btree for the origin
74 * device as it was after the last commit is untouched, ie. we're using
75 * persistent data structures in the functional programming sense.
77 * v) unplug io to this physical block, including the io that triggered
78 * the breaking of sharing.
80 * Steps (ii) and (iii) occur in parallel.
82 * The metadata _doesn't_ need to be committed before the io continues. We
83 * get away with this because the io is always written to a _new_ block.
84 * If there's a crash, then:
86 * - The origin mapping will point to the old origin block (the shared
87 * one). This will contain the data as it was before the io that triggered
88 * the breaking of sharing came in.
90 * - The snap mapping still points to the old block. As it would after
93 * The downside of this scheme is the timestamp magic isn't perfect, and
94 * will continue to think that data block in the snapshot device is shared
95 * even after the write to the origin has broken sharing. I suspect data
96 * blocks will typically be shared by many different devices, so we're
97 * breaking sharing n + 1 times, rather than n, where n is the number of
98 * devices that reference this data block. At the moment I think the
99 * benefits far, far outweigh the disadvantages.
102 /*----------------------------------------------------------------*/
107 static void build_data_key(struct dm_thin_device *td,
108 dm_block_t b, struct dm_cell_key *key)
111 key->dev = dm_thin_dev_id(td);
115 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
116 struct dm_cell_key *key)
119 key->dev = dm_thin_dev_id(td);
123 /*----------------------------------------------------------------*/
126 * A pool device ties together a metadata device and a data device. It
127 * also provides the interface for creating and destroying internal
130 struct dm_thin_new_mapping;
133 * The pool runs in 3 modes. Ordered in degraded order for comparisons.
136 PM_WRITE, /* metadata may be changed */
137 PM_READ_ONLY, /* metadata may not be changed */
138 PM_FAIL, /* all I/O fails */
141 struct pool_features {
144 bool zero_new_blocks:1;
145 bool discard_enabled:1;
146 bool discard_passdown:1;
150 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
151 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
154 struct list_head list;
155 struct dm_target *ti; /* Only set if a pool target is bound */
157 struct mapped_device *pool_md;
158 struct block_device *md_dev;
159 struct dm_pool_metadata *pmd;
161 dm_block_t low_water_blocks;
162 uint32_t sectors_per_block;
163 int sectors_per_block_shift;
165 struct pool_features pf;
166 unsigned low_water_triggered:1; /* A dm event has been sent */
167 unsigned no_free_space:1; /* A -ENOSPC warning has been issued */
169 struct dm_bio_prison *prison;
170 struct dm_kcopyd_client *copier;
172 struct workqueue_struct *wq;
173 struct work_struct worker;
174 struct delayed_work waker;
176 unsigned long last_commit_jiffies;
180 struct bio_list deferred_bios;
181 struct bio_list deferred_flush_bios;
182 struct list_head prepared_mappings;
183 struct list_head prepared_discards;
185 struct bio_list retry_on_resume_list;
187 struct dm_deferred_set *shared_read_ds;
188 struct dm_deferred_set *all_io_ds;
190 struct dm_thin_new_mapping *next_mapping;
191 mempool_t *mapping_pool;
193 process_bio_fn process_bio;
194 process_bio_fn process_discard;
196 process_mapping_fn process_prepared_mapping;
197 process_mapping_fn process_prepared_discard;
200 static enum pool_mode get_pool_mode(struct pool *pool);
201 static void set_pool_mode(struct pool *pool, enum pool_mode mode);
204 * Target context for a pool.
207 struct dm_target *ti;
209 struct dm_dev *data_dev;
210 struct dm_dev *metadata_dev;
211 struct dm_target_callbacks callbacks;
213 dm_block_t low_water_blocks;
214 struct pool_features requested_pf; /* Features requested during table load */
215 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
219 * Target context for a thin.
222 struct dm_dev *pool_dev;
223 struct dm_dev *origin_dev;
227 struct dm_thin_device *td;
230 /*----------------------------------------------------------------*/
232 static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
233 struct dm_bio_prison_cell **cell_result)
236 struct dm_bio_prison_cell *cell_prealloc;
239 * Allocate a cell from the prison's mempool.
240 * This might block but it can't fail.
242 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
244 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
247 * We reused an old cell; we can get rid of
250 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
255 static void cell_release(struct pool *pool,
256 struct dm_bio_prison_cell *cell,
257 struct bio_list *bios)
259 dm_cell_release(pool->prison, cell, bios);
260 dm_bio_prison_free_cell(pool->prison, cell);
263 static void cell_release_no_holder(struct pool *pool,
264 struct dm_bio_prison_cell *cell,
265 struct bio_list *bios)
267 dm_cell_release_no_holder(pool->prison, cell, bios);
268 dm_bio_prison_free_cell(pool->prison, cell);
271 static void cell_error(struct pool *pool,
272 struct dm_bio_prison_cell *cell)
274 dm_cell_error(pool->prison, cell);
275 dm_bio_prison_free_cell(pool->prison, cell);
278 /*----------------------------------------------------------------*/
281 * A global list of pools that uses a struct mapped_device as a key.
283 static struct dm_thin_pool_table {
285 struct list_head pools;
286 } dm_thin_pool_table;
288 static void pool_table_init(void)
290 mutex_init(&dm_thin_pool_table.mutex);
291 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
294 static void __pool_table_insert(struct pool *pool)
296 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
297 list_add(&pool->list, &dm_thin_pool_table.pools);
300 static void __pool_table_remove(struct pool *pool)
302 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
303 list_del(&pool->list);
306 static struct pool *__pool_table_lookup(struct mapped_device *md)
308 struct pool *pool = NULL, *tmp;
310 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
312 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
313 if (tmp->pool_md == md) {
322 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
324 struct pool *pool = NULL, *tmp;
326 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
328 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
329 if (tmp->md_dev == md_dev) {
338 /*----------------------------------------------------------------*/
340 struct dm_thin_endio_hook {
342 struct dm_deferred_entry *shared_read_entry;
343 struct dm_deferred_entry *all_io_entry;
344 struct dm_thin_new_mapping *overwrite_mapping;
347 static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
350 struct bio_list bios;
352 bio_list_init(&bios);
353 bio_list_merge(&bios, master);
354 bio_list_init(master);
356 while ((bio = bio_list_pop(&bios))) {
357 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
360 bio_endio(bio, DM_ENDIO_REQUEUE);
362 bio_list_add(master, bio);
366 static void requeue_io(struct thin_c *tc)
368 struct pool *pool = tc->pool;
371 spin_lock_irqsave(&pool->lock, flags);
372 __requeue_bio_list(tc, &pool->deferred_bios);
373 __requeue_bio_list(tc, &pool->retry_on_resume_list);
374 spin_unlock_irqrestore(&pool->lock, flags);
378 * This section of code contains the logic for processing a thin device's IO.
379 * Much of the code depends on pool object resources (lists, workqueues, etc)
380 * but most is exclusively called from the thin target rather than the thin-pool
384 static bool block_size_is_power_of_two(struct pool *pool)
386 return pool->sectors_per_block_shift >= 0;
389 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
391 struct pool *pool = tc->pool;
392 sector_t block_nr = bio->bi_sector;
394 if (block_size_is_power_of_two(pool))
395 block_nr >>= pool->sectors_per_block_shift;
397 (void) sector_div(block_nr, pool->sectors_per_block);
402 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
404 struct pool *pool = tc->pool;
405 sector_t bi_sector = bio->bi_sector;
407 bio->bi_bdev = tc->pool_dev->bdev;
408 if (block_size_is_power_of_two(pool))
409 bio->bi_sector = (block << pool->sectors_per_block_shift) |
410 (bi_sector & (pool->sectors_per_block - 1));
412 bio->bi_sector = (block * pool->sectors_per_block) +
413 sector_div(bi_sector, pool->sectors_per_block);
416 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
418 bio->bi_bdev = tc->origin_dev->bdev;
421 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
423 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
424 dm_thin_changed_this_transaction(tc->td);
427 static void inc_all_io_entry(struct pool *pool, struct bio *bio)
429 struct dm_thin_endio_hook *h;
431 if (bio->bi_rw & REQ_DISCARD)
434 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
435 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
438 static void issue(struct thin_c *tc, struct bio *bio)
440 struct pool *pool = tc->pool;
443 if (!bio_triggers_commit(tc, bio)) {
444 generic_make_request(bio);
449 * Complete bio with an error if earlier I/O caused changes to
450 * the metadata that can't be committed e.g, due to I/O errors
451 * on the metadata device.
453 if (dm_thin_aborted_changes(tc->td)) {
459 * Batch together any bios that trigger commits and then issue a
460 * single commit for them in process_deferred_bios().
462 spin_lock_irqsave(&pool->lock, flags);
463 bio_list_add(&pool->deferred_flush_bios, bio);
464 spin_unlock_irqrestore(&pool->lock, flags);
467 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
469 remap_to_origin(tc, bio);
473 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
476 remap(tc, bio, block);
481 * wake_worker() is used when new work is queued and when pool_resume is
482 * ready to continue deferred IO processing.
484 static void wake_worker(struct pool *pool)
486 queue_work(pool->wq, &pool->worker);
489 /*----------------------------------------------------------------*/
492 * Bio endio functions.
494 struct dm_thin_new_mapping {
495 struct list_head list;
499 unsigned pass_discard:1;
502 dm_block_t virt_block;
503 dm_block_t data_block;
504 struct dm_bio_prison_cell *cell, *cell2;
508 * If the bio covers the whole area of a block then we can avoid
509 * zeroing or copying. Instead this bio is hooked. The bio will
510 * still be in the cell, so care has to be taken to avoid issuing
514 bio_end_io_t *saved_bi_end_io;
517 static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
519 struct pool *pool = m->tc->pool;
521 if (m->quiesced && m->prepared) {
522 list_add(&m->list, &pool->prepared_mappings);
527 static void copy_complete(int read_err, unsigned long write_err, void *context)
530 struct dm_thin_new_mapping *m = context;
531 struct pool *pool = m->tc->pool;
533 m->err = read_err || write_err ? -EIO : 0;
535 spin_lock_irqsave(&pool->lock, flags);
537 __maybe_add_mapping(m);
538 spin_unlock_irqrestore(&pool->lock, flags);
541 static void overwrite_endio(struct bio *bio, int err)
544 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
545 struct dm_thin_new_mapping *m = h->overwrite_mapping;
546 struct pool *pool = m->tc->pool;
550 spin_lock_irqsave(&pool->lock, flags);
552 __maybe_add_mapping(m);
553 spin_unlock_irqrestore(&pool->lock, flags);
556 /*----------------------------------------------------------------*/
563 * Prepared mapping jobs.
567 * This sends the bios in the cell back to the deferred_bios list.
569 static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
571 struct pool *pool = tc->pool;
574 spin_lock_irqsave(&pool->lock, flags);
575 cell_release(pool, cell, &pool->deferred_bios);
576 spin_unlock_irqrestore(&tc->pool->lock, flags);
582 * Same as cell_defer above, except it omits the original holder of the cell.
584 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
586 struct pool *pool = tc->pool;
589 spin_lock_irqsave(&pool->lock, flags);
590 cell_release_no_holder(pool, cell, &pool->deferred_bios);
591 spin_unlock_irqrestore(&pool->lock, flags);
596 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
599 m->bio->bi_end_io = m->saved_bi_end_io;
600 cell_error(m->tc->pool, m->cell);
602 mempool_free(m, m->tc->pool->mapping_pool);
604 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
606 struct thin_c *tc = m->tc;
607 struct pool *pool = tc->pool;
613 bio->bi_end_io = m->saved_bi_end_io;
616 cell_error(pool, m->cell);
621 * Commit the prepared block into the mapping btree.
622 * Any I/O for this block arriving after this point will get
623 * remapped to it directly.
625 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
627 DMERR_LIMIT("dm_thin_insert_block() failed");
628 cell_error(pool, m->cell);
633 * Release any bios held while the block was being provisioned.
634 * If we are processing a write bio that completely covers the block,
635 * we already processed it so can ignore it now when processing
636 * the bios in the cell.
639 cell_defer_no_holder(tc, m->cell);
642 cell_defer(tc, m->cell);
646 mempool_free(m, pool->mapping_pool);
649 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
651 struct thin_c *tc = m->tc;
653 bio_io_error(m->bio);
654 cell_defer_no_holder(tc, m->cell);
655 cell_defer_no_holder(tc, m->cell2);
656 mempool_free(m, tc->pool->mapping_pool);
659 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
661 struct thin_c *tc = m->tc;
663 inc_all_io_entry(tc->pool, m->bio);
664 cell_defer_no_holder(tc, m->cell);
665 cell_defer_no_holder(tc, m->cell2);
668 remap_and_issue(tc, m->bio, m->data_block);
670 bio_endio(m->bio, 0);
672 mempool_free(m, tc->pool->mapping_pool);
675 static void process_prepared_discard(struct dm_thin_new_mapping *m)
678 struct thin_c *tc = m->tc;
680 r = dm_thin_remove_block(tc->td, m->virt_block);
682 DMERR_LIMIT("dm_thin_remove_block() failed");
684 process_prepared_discard_passdown(m);
687 static void process_prepared(struct pool *pool, struct list_head *head,
688 process_mapping_fn *fn)
691 struct list_head maps;
692 struct dm_thin_new_mapping *m, *tmp;
694 INIT_LIST_HEAD(&maps);
695 spin_lock_irqsave(&pool->lock, flags);
696 list_splice_init(head, &maps);
697 spin_unlock_irqrestore(&pool->lock, flags);
699 list_for_each_entry_safe(m, tmp, &maps, list)
706 static int io_overlaps_block(struct pool *pool, struct bio *bio)
708 return bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT);
711 static int io_overwrites_block(struct pool *pool, struct bio *bio)
713 return (bio_data_dir(bio) == WRITE) &&
714 io_overlaps_block(pool, bio);
717 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
720 *save = bio->bi_end_io;
724 static int ensure_next_mapping(struct pool *pool)
726 if (pool->next_mapping)
729 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
731 return pool->next_mapping ? 0 : -ENOMEM;
734 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
736 struct dm_thin_new_mapping *r = pool->next_mapping;
738 BUG_ON(!pool->next_mapping);
740 pool->next_mapping = NULL;
745 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
746 struct dm_dev *origin, dm_block_t data_origin,
747 dm_block_t data_dest,
748 struct dm_bio_prison_cell *cell, struct bio *bio)
751 struct pool *pool = tc->pool;
752 struct dm_thin_new_mapping *m = get_next_mapping(pool);
754 INIT_LIST_HEAD(&m->list);
758 m->virt_block = virt_block;
759 m->data_block = data_dest;
764 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
768 * IO to pool_dev remaps to the pool target's data_dev.
770 * If the whole block of data is being overwritten, we can issue the
771 * bio immediately. Otherwise we use kcopyd to clone the data first.
773 if (io_overwrites_block(pool, bio)) {
774 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
776 h->overwrite_mapping = m;
778 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
779 inc_all_io_entry(pool, bio);
780 remap_and_issue(tc, bio, data_dest);
782 struct dm_io_region from, to;
784 from.bdev = origin->bdev;
785 from.sector = data_origin * pool->sectors_per_block;
786 from.count = pool->sectors_per_block;
788 to.bdev = tc->pool_dev->bdev;
789 to.sector = data_dest * pool->sectors_per_block;
790 to.count = pool->sectors_per_block;
792 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
793 0, copy_complete, m);
795 mempool_free(m, pool->mapping_pool);
796 DMERR_LIMIT("dm_kcopyd_copy() failed");
797 cell_error(pool, cell);
802 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
803 dm_block_t data_origin, dm_block_t data_dest,
804 struct dm_bio_prison_cell *cell, struct bio *bio)
806 schedule_copy(tc, virt_block, tc->pool_dev,
807 data_origin, data_dest, cell, bio);
810 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
811 dm_block_t data_dest,
812 struct dm_bio_prison_cell *cell, struct bio *bio)
814 schedule_copy(tc, virt_block, tc->origin_dev,
815 virt_block, data_dest, cell, bio);
818 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
819 dm_block_t data_block, struct dm_bio_prison_cell *cell,
822 struct pool *pool = tc->pool;
823 struct dm_thin_new_mapping *m = get_next_mapping(pool);
825 INIT_LIST_HEAD(&m->list);
829 m->virt_block = virt_block;
830 m->data_block = data_block;
836 * If the whole block of data is being overwritten or we are not
837 * zeroing pre-existing data, we can issue the bio immediately.
838 * Otherwise we use kcopyd to zero the data first.
840 if (!pool->pf.zero_new_blocks)
841 process_prepared_mapping(m);
843 else if (io_overwrites_block(pool, bio)) {
844 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
846 h->overwrite_mapping = m;
848 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
849 inc_all_io_entry(pool, bio);
850 remap_and_issue(tc, bio, data_block);
853 struct dm_io_region to;
855 to.bdev = tc->pool_dev->bdev;
856 to.sector = data_block * pool->sectors_per_block;
857 to.count = pool->sectors_per_block;
859 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
861 mempool_free(m, pool->mapping_pool);
862 DMERR_LIMIT("dm_kcopyd_zero() failed");
863 cell_error(pool, cell);
868 static int commit(struct pool *pool)
872 r = dm_pool_commit_metadata(pool->pmd);
874 DMERR_LIMIT("commit failed: error = %d", r);
880 * A non-zero return indicates read_only or fail_io mode.
881 * Many callers don't care about the return value.
883 static int commit_or_fallback(struct pool *pool)
887 if (get_pool_mode(pool) != PM_WRITE)
892 set_pool_mode(pool, PM_READ_ONLY);
897 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
900 dm_block_t free_blocks;
902 struct pool *pool = tc->pool;
904 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
908 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
909 DMWARN("%s: reached low water mark, sending event.",
910 dm_device_name(pool->pool_md));
911 spin_lock_irqsave(&pool->lock, flags);
912 pool->low_water_triggered = 1;
913 spin_unlock_irqrestore(&pool->lock, flags);
914 dm_table_event(pool->ti->table);
918 if (pool->no_free_space)
922 * Try to commit to see if that will free up some
925 (void) commit_or_fallback(pool);
927 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
932 * If we still have no space we set a flag to avoid
933 * doing all this checking and return -ENOSPC.
936 DMWARN("%s: no free space available.",
937 dm_device_name(pool->pool_md));
938 spin_lock_irqsave(&pool->lock, flags);
939 pool->no_free_space = 1;
940 spin_unlock_irqrestore(&pool->lock, flags);
946 r = dm_pool_alloc_data_block(pool->pmd, result);
954 * If we have run out of space, queue bios until the device is
955 * resumed, presumably after having been reloaded with more space.
957 static void retry_on_resume(struct bio *bio)
959 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
960 struct thin_c *tc = h->tc;
961 struct pool *pool = tc->pool;
964 spin_lock_irqsave(&pool->lock, flags);
965 bio_list_add(&pool->retry_on_resume_list, bio);
966 spin_unlock_irqrestore(&pool->lock, flags);
969 static void no_space(struct pool *pool, struct dm_bio_prison_cell *cell)
972 struct bio_list bios;
974 bio_list_init(&bios);
975 cell_release(pool, cell, &bios);
977 while ((bio = bio_list_pop(&bios)))
978 retry_on_resume(bio);
981 static void process_discard(struct thin_c *tc, struct bio *bio)
985 struct pool *pool = tc->pool;
986 struct dm_bio_prison_cell *cell, *cell2;
987 struct dm_cell_key key, key2;
988 dm_block_t block = get_bio_block(tc, bio);
989 struct dm_thin_lookup_result lookup_result;
990 struct dm_thin_new_mapping *m;
992 build_virtual_key(tc->td, block, &key);
993 if (bio_detain(tc->pool, &key, bio, &cell))
996 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1000 * Check nobody is fiddling with this pool block. This can
1001 * happen if someone's in the process of breaking sharing
1004 build_data_key(tc->td, lookup_result.block, &key2);
1005 if (bio_detain(tc->pool, &key2, bio, &cell2)) {
1006 cell_defer_no_holder(tc, cell);
1010 if (io_overlaps_block(pool, bio)) {
1012 * IO may still be going to the destination block. We must
1013 * quiesce before we can do the removal.
1015 m = get_next_mapping(pool);
1017 m->pass_discard = (!lookup_result.shared) && pool->pf.discard_passdown;
1018 m->virt_block = block;
1019 m->data_block = lookup_result.block;
1025 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
1026 spin_lock_irqsave(&pool->lock, flags);
1027 list_add(&m->list, &pool->prepared_discards);
1028 spin_unlock_irqrestore(&pool->lock, flags);
1032 inc_all_io_entry(pool, bio);
1033 cell_defer_no_holder(tc, cell);
1034 cell_defer_no_holder(tc, cell2);
1037 * The DM core makes sure that the discard doesn't span
1038 * a block boundary. So we submit the discard of a
1039 * partial block appropriately.
1041 if ((!lookup_result.shared) && pool->pf.discard_passdown)
1042 remap_and_issue(tc, bio, lookup_result.block);
1050 * It isn't provisioned, just forget it.
1052 cell_defer_no_holder(tc, cell);
1057 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1059 cell_defer_no_holder(tc, cell);
1065 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1066 struct dm_cell_key *key,
1067 struct dm_thin_lookup_result *lookup_result,
1068 struct dm_bio_prison_cell *cell)
1071 dm_block_t data_block;
1073 r = alloc_data_block(tc, &data_block);
1076 schedule_internal_copy(tc, block, lookup_result->block,
1077 data_block, cell, bio);
1081 no_space(tc->pool, cell);
1085 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1087 cell_error(tc->pool, cell);
1092 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1094 struct dm_thin_lookup_result *lookup_result)
1096 struct dm_bio_prison_cell *cell;
1097 struct pool *pool = tc->pool;
1098 struct dm_cell_key key;
1101 * If cell is already occupied, then sharing is already in the process
1102 * of being broken so we have nothing further to do here.
1104 build_data_key(tc->td, lookup_result->block, &key);
1105 if (bio_detain(pool, &key, bio, &cell))
1108 if (bio_data_dir(bio) == WRITE && bio->bi_size)
1109 break_sharing(tc, bio, block, &key, lookup_result, cell);
1111 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1113 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1114 inc_all_io_entry(pool, bio);
1115 cell_defer_no_holder(tc, cell);
1117 remap_and_issue(tc, bio, lookup_result->block);
1121 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1122 struct dm_bio_prison_cell *cell)
1125 dm_block_t data_block;
1126 struct pool *pool = tc->pool;
1129 * Remap empty bios (flushes) immediately, without provisioning.
1131 if (!bio->bi_size) {
1132 inc_all_io_entry(pool, bio);
1133 cell_defer_no_holder(tc, cell);
1135 remap_and_issue(tc, bio, 0);
1140 * Fill read bios with zeroes and complete them immediately.
1142 if (bio_data_dir(bio) == READ) {
1144 cell_defer_no_holder(tc, cell);
1149 r = alloc_data_block(tc, &data_block);
1153 schedule_external_copy(tc, block, data_block, cell, bio);
1155 schedule_zero(tc, block, data_block, cell, bio);
1159 no_space(pool, cell);
1163 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1165 set_pool_mode(pool, PM_READ_ONLY);
1166 cell_error(pool, cell);
1171 static void process_bio(struct thin_c *tc, struct bio *bio)
1174 struct pool *pool = tc->pool;
1175 dm_block_t block = get_bio_block(tc, bio);
1176 struct dm_bio_prison_cell *cell;
1177 struct dm_cell_key key;
1178 struct dm_thin_lookup_result lookup_result;
1181 * If cell is already occupied, then the block is already
1182 * being provisioned so we have nothing further to do here.
1184 build_virtual_key(tc->td, block, &key);
1185 if (bio_detain(pool, &key, bio, &cell))
1188 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1191 if (lookup_result.shared) {
1192 process_shared_bio(tc, bio, block, &lookup_result);
1193 cell_defer_no_holder(tc, cell); /* FIXME: pass this cell into process_shared? */
1195 inc_all_io_entry(pool, bio);
1196 cell_defer_no_holder(tc, cell);
1198 remap_and_issue(tc, bio, lookup_result.block);
1203 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1204 inc_all_io_entry(pool, bio);
1205 cell_defer_no_holder(tc, cell);
1207 remap_to_origin_and_issue(tc, bio);
1209 provision_block(tc, bio, block, cell);
1213 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1215 cell_defer_no_holder(tc, cell);
1221 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1224 int rw = bio_data_dir(bio);
1225 dm_block_t block = get_bio_block(tc, bio);
1226 struct dm_thin_lookup_result lookup_result;
1228 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1231 if (lookup_result.shared && (rw == WRITE) && bio->bi_size)
1234 inc_all_io_entry(tc->pool, bio);
1235 remap_and_issue(tc, bio, lookup_result.block);
1245 if (tc->origin_dev) {
1246 inc_all_io_entry(tc->pool, bio);
1247 remap_to_origin_and_issue(tc, bio);
1256 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1263 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1268 static int need_commit_due_to_time(struct pool *pool)
1270 return jiffies < pool->last_commit_jiffies ||
1271 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1274 static void process_deferred_bios(struct pool *pool)
1276 unsigned long flags;
1278 struct bio_list bios;
1280 bio_list_init(&bios);
1282 spin_lock_irqsave(&pool->lock, flags);
1283 bio_list_merge(&bios, &pool->deferred_bios);
1284 bio_list_init(&pool->deferred_bios);
1285 spin_unlock_irqrestore(&pool->lock, flags);
1287 while ((bio = bio_list_pop(&bios))) {
1288 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1289 struct thin_c *tc = h->tc;
1292 * If we've got no free new_mapping structs, and processing
1293 * this bio might require one, we pause until there are some
1294 * prepared mappings to process.
1296 if (ensure_next_mapping(pool)) {
1297 spin_lock_irqsave(&pool->lock, flags);
1298 bio_list_merge(&pool->deferred_bios, &bios);
1299 spin_unlock_irqrestore(&pool->lock, flags);
1304 if (bio->bi_rw & REQ_DISCARD)
1305 pool->process_discard(tc, bio);
1307 pool->process_bio(tc, bio);
1311 * If there are any deferred flush bios, we must commit
1312 * the metadata before issuing them.
1314 bio_list_init(&bios);
1315 spin_lock_irqsave(&pool->lock, flags);
1316 bio_list_merge(&bios, &pool->deferred_flush_bios);
1317 bio_list_init(&pool->deferred_flush_bios);
1318 spin_unlock_irqrestore(&pool->lock, flags);
1320 if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))
1323 if (commit_or_fallback(pool)) {
1324 while ((bio = bio_list_pop(&bios)))
1328 pool->last_commit_jiffies = jiffies;
1330 while ((bio = bio_list_pop(&bios)))
1331 generic_make_request(bio);
1334 static void do_worker(struct work_struct *ws)
1336 struct pool *pool = container_of(ws, struct pool, worker);
1338 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1339 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1340 process_deferred_bios(pool);
1344 * We want to commit periodically so that not too much
1345 * unwritten data builds up.
1347 static void do_waker(struct work_struct *ws)
1349 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1351 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1354 /*----------------------------------------------------------------*/
1356 static enum pool_mode get_pool_mode(struct pool *pool)
1358 return pool->pf.mode;
1361 static void set_pool_mode(struct pool *pool, enum pool_mode mode)
1365 pool->pf.mode = mode;
1369 DMERR("switching pool to failure mode");
1370 pool->process_bio = process_bio_fail;
1371 pool->process_discard = process_bio_fail;
1372 pool->process_prepared_mapping = process_prepared_mapping_fail;
1373 pool->process_prepared_discard = process_prepared_discard_fail;
1377 DMERR("switching pool to read-only mode");
1378 r = dm_pool_abort_metadata(pool->pmd);
1380 DMERR("aborting transaction failed");
1381 set_pool_mode(pool, PM_FAIL);
1383 dm_pool_metadata_read_only(pool->pmd);
1384 pool->process_bio = process_bio_read_only;
1385 pool->process_discard = process_discard;
1386 pool->process_prepared_mapping = process_prepared_mapping_fail;
1387 pool->process_prepared_discard = process_prepared_discard_passdown;
1392 pool->process_bio = process_bio;
1393 pool->process_discard = process_discard;
1394 pool->process_prepared_mapping = process_prepared_mapping;
1395 pool->process_prepared_discard = process_prepared_discard;
1400 /*----------------------------------------------------------------*/
1403 * Mapping functions.
1407 * Called only while mapping a thin bio to hand it over to the workqueue.
1409 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1411 unsigned long flags;
1412 struct pool *pool = tc->pool;
1414 spin_lock_irqsave(&pool->lock, flags);
1415 bio_list_add(&pool->deferred_bios, bio);
1416 spin_unlock_irqrestore(&pool->lock, flags);
1421 static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
1423 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1426 h->shared_read_entry = NULL;
1427 h->all_io_entry = NULL;
1428 h->overwrite_mapping = NULL;
1432 * Non-blocking function called from the thin target's map function.
1434 static int thin_bio_map(struct dm_target *ti, struct bio *bio)
1437 struct thin_c *tc = ti->private;
1438 dm_block_t block = get_bio_block(tc, bio);
1439 struct dm_thin_device *td = tc->td;
1440 struct dm_thin_lookup_result result;
1441 struct dm_bio_prison_cell *cell1, *cell2;
1442 struct dm_cell_key key;
1444 thin_hook_bio(tc, bio);
1446 if (get_pool_mode(tc->pool) == PM_FAIL) {
1448 return DM_MAPIO_SUBMITTED;
1451 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
1452 thin_defer_bio(tc, bio);
1453 return DM_MAPIO_SUBMITTED;
1456 r = dm_thin_find_block(td, block, 0, &result);
1459 * Note that we defer readahead too.
1463 if (unlikely(result.shared)) {
1465 * We have a race condition here between the
1466 * result.shared value returned by the lookup and
1467 * snapshot creation, which may cause new
1470 * To avoid this always quiesce the origin before
1471 * taking the snap. You want to do this anyway to
1472 * ensure a consistent application view
1475 * More distant ancestors are irrelevant. The
1476 * shared flag will be set in their case.
1478 thin_defer_bio(tc, bio);
1479 return DM_MAPIO_SUBMITTED;
1482 build_virtual_key(tc->td, block, &key);
1483 if (bio_detain(tc->pool, &key, bio, &cell1))
1484 return DM_MAPIO_SUBMITTED;
1486 build_data_key(tc->td, result.block, &key);
1487 if (bio_detain(tc->pool, &key, bio, &cell2)) {
1488 cell_defer_no_holder(tc, cell1);
1489 return DM_MAPIO_SUBMITTED;
1492 inc_all_io_entry(tc->pool, bio);
1493 cell_defer_no_holder(tc, cell2);
1494 cell_defer_no_holder(tc, cell1);
1496 remap(tc, bio, result.block);
1497 return DM_MAPIO_REMAPPED;
1500 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
1502 * This block isn't provisioned, and we have no way
1503 * of doing so. Just error it.
1506 return DM_MAPIO_SUBMITTED;
1512 * In future, the failed dm_thin_find_block above could
1513 * provide the hint to load the metadata into cache.
1515 thin_defer_bio(tc, bio);
1516 return DM_MAPIO_SUBMITTED;
1520 * Must always call bio_io_error on failure.
1521 * dm_thin_find_block can fail with -EINVAL if the
1522 * pool is switched to fail-io mode.
1525 return DM_MAPIO_SUBMITTED;
1529 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1532 unsigned long flags;
1533 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1535 spin_lock_irqsave(&pt->pool->lock, flags);
1536 r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1537 spin_unlock_irqrestore(&pt->pool->lock, flags);
1540 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1541 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1547 static void __requeue_bios(struct pool *pool)
1549 bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1550 bio_list_init(&pool->retry_on_resume_list);
1553 /*----------------------------------------------------------------
1554 * Binding of control targets to a pool object
1555 *--------------------------------------------------------------*/
1556 static bool data_dev_supports_discard(struct pool_c *pt)
1558 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1560 return q && blk_queue_discard(q);
1564 * If discard_passdown was enabled verify that the data device
1565 * supports discards. Disable discard_passdown if not.
1567 static void disable_passdown_if_not_supported(struct pool_c *pt)
1569 struct pool *pool = pt->pool;
1570 struct block_device *data_bdev = pt->data_dev->bdev;
1571 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
1572 sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
1573 const char *reason = NULL;
1574 char buf[BDEVNAME_SIZE];
1576 if (!pt->adjusted_pf.discard_passdown)
1579 if (!data_dev_supports_discard(pt))
1580 reason = "discard unsupported";
1582 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
1583 reason = "max discard sectors smaller than a block";
1585 else if (data_limits->discard_granularity > block_size)
1586 reason = "discard granularity larger than a block";
1588 else if (block_size & (data_limits->discard_granularity - 1))
1589 reason = "discard granularity not a factor of block size";
1592 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
1593 pt->adjusted_pf.discard_passdown = false;
1597 static int bind_control_target(struct pool *pool, struct dm_target *ti)
1599 struct pool_c *pt = ti->private;
1602 * We want to make sure that degraded pools are never upgraded.
1604 enum pool_mode old_mode = pool->pf.mode;
1605 enum pool_mode new_mode = pt->adjusted_pf.mode;
1607 if (old_mode > new_mode)
1608 new_mode = old_mode;
1611 pool->low_water_blocks = pt->low_water_blocks;
1612 pool->pf = pt->adjusted_pf;
1614 set_pool_mode(pool, new_mode);
1619 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1625 /*----------------------------------------------------------------
1627 *--------------------------------------------------------------*/
1628 /* Initialize pool features. */
1629 static void pool_features_init(struct pool_features *pf)
1631 pf->mode = PM_WRITE;
1632 pf->zero_new_blocks = true;
1633 pf->discard_enabled = true;
1634 pf->discard_passdown = true;
1637 static void __pool_destroy(struct pool *pool)
1639 __pool_table_remove(pool);
1641 if (dm_pool_metadata_close(pool->pmd) < 0)
1642 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1644 dm_bio_prison_destroy(pool->prison);
1645 dm_kcopyd_client_destroy(pool->copier);
1648 destroy_workqueue(pool->wq);
1650 if (pool->next_mapping)
1651 mempool_free(pool->next_mapping, pool->mapping_pool);
1652 mempool_destroy(pool->mapping_pool);
1653 dm_deferred_set_destroy(pool->shared_read_ds);
1654 dm_deferred_set_destroy(pool->all_io_ds);
1658 static struct kmem_cache *_new_mapping_cache;
1660 static struct pool *pool_create(struct mapped_device *pool_md,
1661 struct block_device *metadata_dev,
1662 unsigned long block_size,
1663 int read_only, char **error)
1668 struct dm_pool_metadata *pmd;
1669 bool format_device = read_only ? false : true;
1671 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
1673 *error = "Error creating metadata object";
1674 return (struct pool *)pmd;
1677 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1679 *error = "Error allocating memory for pool";
1680 err_p = ERR_PTR(-ENOMEM);
1685 pool->sectors_per_block = block_size;
1686 if (block_size & (block_size - 1))
1687 pool->sectors_per_block_shift = -1;
1689 pool->sectors_per_block_shift = __ffs(block_size);
1690 pool->low_water_blocks = 0;
1691 pool_features_init(&pool->pf);
1692 pool->prison = dm_bio_prison_create(PRISON_CELLS);
1693 if (!pool->prison) {
1694 *error = "Error creating pool's bio prison";
1695 err_p = ERR_PTR(-ENOMEM);
1699 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1700 if (IS_ERR(pool->copier)) {
1701 r = PTR_ERR(pool->copier);
1702 *error = "Error creating pool's kcopyd client";
1704 goto bad_kcopyd_client;
1708 * Create singlethreaded workqueue that will service all devices
1709 * that use this metadata.
1711 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1713 *error = "Error creating pool's workqueue";
1714 err_p = ERR_PTR(-ENOMEM);
1718 INIT_WORK(&pool->worker, do_worker);
1719 INIT_DELAYED_WORK(&pool->waker, do_waker);
1720 spin_lock_init(&pool->lock);
1721 bio_list_init(&pool->deferred_bios);
1722 bio_list_init(&pool->deferred_flush_bios);
1723 INIT_LIST_HEAD(&pool->prepared_mappings);
1724 INIT_LIST_HEAD(&pool->prepared_discards);
1725 pool->low_water_triggered = 0;
1726 pool->no_free_space = 0;
1727 bio_list_init(&pool->retry_on_resume_list);
1729 pool->shared_read_ds = dm_deferred_set_create();
1730 if (!pool->shared_read_ds) {
1731 *error = "Error creating pool's shared read deferred set";
1732 err_p = ERR_PTR(-ENOMEM);
1733 goto bad_shared_read_ds;
1736 pool->all_io_ds = dm_deferred_set_create();
1737 if (!pool->all_io_ds) {
1738 *error = "Error creating pool's all io deferred set";
1739 err_p = ERR_PTR(-ENOMEM);
1743 pool->next_mapping = NULL;
1744 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
1745 _new_mapping_cache);
1746 if (!pool->mapping_pool) {
1747 *error = "Error creating pool's mapping mempool";
1748 err_p = ERR_PTR(-ENOMEM);
1749 goto bad_mapping_pool;
1752 pool->ref_count = 1;
1753 pool->last_commit_jiffies = jiffies;
1754 pool->pool_md = pool_md;
1755 pool->md_dev = metadata_dev;
1756 __pool_table_insert(pool);
1761 dm_deferred_set_destroy(pool->all_io_ds);
1763 dm_deferred_set_destroy(pool->shared_read_ds);
1765 destroy_workqueue(pool->wq);
1767 dm_kcopyd_client_destroy(pool->copier);
1769 dm_bio_prison_destroy(pool->prison);
1773 if (dm_pool_metadata_close(pmd))
1774 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1779 static void __pool_inc(struct pool *pool)
1781 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1785 static void __pool_dec(struct pool *pool)
1787 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1788 BUG_ON(!pool->ref_count);
1789 if (!--pool->ref_count)
1790 __pool_destroy(pool);
1793 static struct pool *__pool_find(struct mapped_device *pool_md,
1794 struct block_device *metadata_dev,
1795 unsigned long block_size, int read_only,
1796 char **error, int *created)
1798 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1801 if (pool->pool_md != pool_md) {
1802 *error = "metadata device already in use by a pool";
1803 return ERR_PTR(-EBUSY);
1808 pool = __pool_table_lookup(pool_md);
1810 if (pool->md_dev != metadata_dev) {
1811 *error = "different pool cannot replace a pool";
1812 return ERR_PTR(-EINVAL);
1817 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
1825 /*----------------------------------------------------------------
1826 * Pool target methods
1827 *--------------------------------------------------------------*/
1828 static void pool_dtr(struct dm_target *ti)
1830 struct pool_c *pt = ti->private;
1832 mutex_lock(&dm_thin_pool_table.mutex);
1834 unbind_control_target(pt->pool, ti);
1835 __pool_dec(pt->pool);
1836 dm_put_device(ti, pt->metadata_dev);
1837 dm_put_device(ti, pt->data_dev);
1840 mutex_unlock(&dm_thin_pool_table.mutex);
1843 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
1844 struct dm_target *ti)
1848 const char *arg_name;
1850 static struct dm_arg _args[] = {
1851 {0, 3, "Invalid number of pool feature arguments"},
1855 * No feature arguments supplied.
1860 r = dm_read_arg_group(_args, as, &argc, &ti->error);
1864 while (argc && !r) {
1865 arg_name = dm_shift_arg(as);
1868 if (!strcasecmp(arg_name, "skip_block_zeroing"))
1869 pf->zero_new_blocks = false;
1871 else if (!strcasecmp(arg_name, "ignore_discard"))
1872 pf->discard_enabled = false;
1874 else if (!strcasecmp(arg_name, "no_discard_passdown"))
1875 pf->discard_passdown = false;
1877 else if (!strcasecmp(arg_name, "read_only"))
1878 pf->mode = PM_READ_ONLY;
1881 ti->error = "Unrecognised pool feature requested";
1891 * thin-pool <metadata dev> <data dev>
1892 * <data block size (sectors)>
1893 * <low water mark (blocks)>
1894 * [<#feature args> [<arg>]*]
1896 * Optional feature arguments are:
1897 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1898 * ignore_discard: disable discard
1899 * no_discard_passdown: don't pass discards down to the data device
1901 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
1903 int r, pool_created = 0;
1906 struct pool_features pf;
1907 struct dm_arg_set as;
1908 struct dm_dev *data_dev;
1909 unsigned long block_size;
1910 dm_block_t low_water_blocks;
1911 struct dm_dev *metadata_dev;
1912 sector_t metadata_dev_size;
1913 char b[BDEVNAME_SIZE];
1916 * FIXME Remove validation from scope of lock.
1918 mutex_lock(&dm_thin_pool_table.mutex);
1921 ti->error = "Invalid argument count";
1928 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev);
1930 ti->error = "Error opening metadata block device";
1934 metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT;
1935 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
1936 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1937 bdevname(metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
1939 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
1941 ti->error = "Error getting data device";
1945 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
1946 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
1947 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
1948 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
1949 ti->error = "Invalid block size";
1954 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
1955 ti->error = "Invalid low water mark";
1961 * Set default pool features.
1963 pool_features_init(&pf);
1965 dm_consume_args(&as, 4);
1966 r = parse_pool_features(&as, &pf, ti);
1970 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
1976 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
1977 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
1984 * 'pool_created' reflects whether this is the first table load.
1985 * Top level discard support is not allowed to be changed after
1986 * initial load. This would require a pool reload to trigger thin
1989 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
1990 ti->error = "Discard support cannot be disabled once enabled";
1992 goto out_flags_changed;
1997 pt->metadata_dev = metadata_dev;
1998 pt->data_dev = data_dev;
1999 pt->low_water_blocks = low_water_blocks;
2000 pt->adjusted_pf = pt->requested_pf = pf;
2001 ti->num_flush_bios = 1;
2004 * Only need to enable discards if the pool should pass
2005 * them down to the data device. The thin device's discard
2006 * processing will cause mappings to be removed from the btree.
2008 if (pf.discard_enabled && pf.discard_passdown) {
2009 ti->num_discard_bios = 1;
2012 * Setting 'discards_supported' circumvents the normal
2013 * stacking of discard limits (this keeps the pool and
2014 * thin devices' discard limits consistent).
2016 ti->discards_supported = true;
2017 ti->discard_zeroes_data_unsupported = true;
2021 pt->callbacks.congested_fn = pool_is_congested;
2022 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2024 mutex_unlock(&dm_thin_pool_table.mutex);
2033 dm_put_device(ti, data_dev);
2035 dm_put_device(ti, metadata_dev);
2037 mutex_unlock(&dm_thin_pool_table.mutex);
2042 static int pool_map(struct dm_target *ti, struct bio *bio)
2045 struct pool_c *pt = ti->private;
2046 struct pool *pool = pt->pool;
2047 unsigned long flags;
2050 * As this is a singleton target, ti->begin is always zero.
2052 spin_lock_irqsave(&pool->lock, flags);
2053 bio->bi_bdev = pt->data_dev->bdev;
2054 r = DM_MAPIO_REMAPPED;
2055 spin_unlock_irqrestore(&pool->lock, flags);
2061 * Retrieves the number of blocks of the data device from
2062 * the superblock and compares it to the actual device size,
2063 * thus resizing the data device in case it has grown.
2065 * This both copes with opening preallocated data devices in the ctr
2066 * being followed by a resume
2068 * calling the resume method individually after userspace has
2069 * grown the data device in reaction to a table event.
2071 static int pool_preresume(struct dm_target *ti)
2074 struct pool_c *pt = ti->private;
2075 struct pool *pool = pt->pool;
2076 sector_t data_size = ti->len;
2077 dm_block_t sb_data_size;
2080 * Take control of the pool object.
2082 r = bind_control_target(pool, ti);
2086 (void) sector_div(data_size, pool->sectors_per_block);
2088 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2090 DMERR("failed to retrieve data device size");
2094 if (data_size < sb_data_size) {
2095 DMERR("pool target too small, is %llu blocks (expected %llu)",
2096 (unsigned long long)data_size, sb_data_size);
2099 } else if (data_size > sb_data_size) {
2100 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2102 DMERR("failed to resize data device");
2103 /* FIXME Stricter than necessary: Rollback transaction instead here */
2104 set_pool_mode(pool, PM_READ_ONLY);
2108 (void) commit_or_fallback(pool);
2114 static void pool_resume(struct dm_target *ti)
2116 struct pool_c *pt = ti->private;
2117 struct pool *pool = pt->pool;
2118 unsigned long flags;
2120 spin_lock_irqsave(&pool->lock, flags);
2121 pool->low_water_triggered = 0;
2122 pool->no_free_space = 0;
2123 __requeue_bios(pool);
2124 spin_unlock_irqrestore(&pool->lock, flags);
2126 do_waker(&pool->waker.work);
2129 static void pool_postsuspend(struct dm_target *ti)
2131 struct pool_c *pt = ti->private;
2132 struct pool *pool = pt->pool;
2134 cancel_delayed_work(&pool->waker);
2135 flush_workqueue(pool->wq);
2136 (void) commit_or_fallback(pool);
2139 static int check_arg_count(unsigned argc, unsigned args_required)
2141 if (argc != args_required) {
2142 DMWARN("Message received with %u arguments instead of %u.",
2143 argc, args_required);
2150 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2152 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2153 *dev_id <= MAX_DEV_ID)
2157 DMWARN("Message received with invalid device id: %s", arg);
2162 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2167 r = check_arg_count(argc, 2);
2171 r = read_dev_id(argv[1], &dev_id, 1);
2175 r = dm_pool_create_thin(pool->pmd, dev_id);
2177 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2185 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2188 dm_thin_id origin_dev_id;
2191 r = check_arg_count(argc, 3);
2195 r = read_dev_id(argv[1], &dev_id, 1);
2199 r = read_dev_id(argv[2], &origin_dev_id, 1);
2203 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2205 DMWARN("Creation of new snapshot %s of device %s failed.",
2213 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2218 r = check_arg_count(argc, 2);
2222 r = read_dev_id(argv[1], &dev_id, 1);
2226 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2228 DMWARN("Deletion of thin device %s failed.", argv[1]);
2233 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2235 dm_thin_id old_id, new_id;
2238 r = check_arg_count(argc, 3);
2242 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2243 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2247 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2248 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2252 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2254 DMWARN("Failed to change transaction id from %s to %s.",
2262 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2266 r = check_arg_count(argc, 1);
2270 (void) commit_or_fallback(pool);
2272 r = dm_pool_reserve_metadata_snap(pool->pmd);
2274 DMWARN("reserve_metadata_snap message failed.");
2279 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2283 r = check_arg_count(argc, 1);
2287 r = dm_pool_release_metadata_snap(pool->pmd);
2289 DMWARN("release_metadata_snap message failed.");
2295 * Messages supported:
2296 * create_thin <dev_id>
2297 * create_snap <dev_id> <origin_id>
2299 * trim <dev_id> <new_size_in_sectors>
2300 * set_transaction_id <current_trans_id> <new_trans_id>
2301 * reserve_metadata_snap
2302 * release_metadata_snap
2304 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2307 struct pool_c *pt = ti->private;
2308 struct pool *pool = pt->pool;
2310 if (!strcasecmp(argv[0], "create_thin"))
2311 r = process_create_thin_mesg(argc, argv, pool);
2313 else if (!strcasecmp(argv[0], "create_snap"))
2314 r = process_create_snap_mesg(argc, argv, pool);
2316 else if (!strcasecmp(argv[0], "delete"))
2317 r = process_delete_mesg(argc, argv, pool);
2319 else if (!strcasecmp(argv[0], "set_transaction_id"))
2320 r = process_set_transaction_id_mesg(argc, argv, pool);
2322 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
2323 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
2325 else if (!strcasecmp(argv[0], "release_metadata_snap"))
2326 r = process_release_metadata_snap_mesg(argc, argv, pool);
2329 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2332 (void) commit_or_fallback(pool);
2337 static void emit_flags(struct pool_features *pf, char *result,
2338 unsigned sz, unsigned maxlen)
2340 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
2341 !pf->discard_passdown + (pf->mode == PM_READ_ONLY);
2342 DMEMIT("%u ", count);
2344 if (!pf->zero_new_blocks)
2345 DMEMIT("skip_block_zeroing ");
2347 if (!pf->discard_enabled)
2348 DMEMIT("ignore_discard ");
2350 if (!pf->discard_passdown)
2351 DMEMIT("no_discard_passdown ");
2353 if (pf->mode == PM_READ_ONLY)
2354 DMEMIT("read_only ");
2359 * <transaction id> <used metadata sectors>/<total metadata sectors>
2360 * <used data sectors>/<total data sectors> <held metadata root>
2362 static void pool_status(struct dm_target *ti, status_type_t type,
2363 unsigned status_flags, char *result, unsigned maxlen)
2367 uint64_t transaction_id;
2368 dm_block_t nr_free_blocks_data;
2369 dm_block_t nr_free_blocks_metadata;
2370 dm_block_t nr_blocks_data;
2371 dm_block_t nr_blocks_metadata;
2372 dm_block_t held_root;
2373 char buf[BDEVNAME_SIZE];
2374 char buf2[BDEVNAME_SIZE];
2375 struct pool_c *pt = ti->private;
2376 struct pool *pool = pt->pool;
2379 case STATUSTYPE_INFO:
2380 if (get_pool_mode(pool) == PM_FAIL) {
2385 /* Commit to ensure statistics aren't out-of-date */
2386 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
2387 (void) commit_or_fallback(pool);
2389 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
2391 DMERR("dm_pool_get_metadata_transaction_id returned %d", r);
2395 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
2397 DMERR("dm_pool_get_free_metadata_block_count returned %d", r);
2401 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2403 DMERR("dm_pool_get_metadata_dev_size returned %d", r);
2407 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
2409 DMERR("dm_pool_get_free_block_count returned %d", r);
2413 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2415 DMERR("dm_pool_get_data_dev_size returned %d", r);
2419 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
2421 DMERR("dm_pool_get_metadata_snap returned %d", r);
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);
2433 DMEMIT("%llu ", held_root);
2437 if (pool->pf.mode == PM_READ_ONLY)
2442 if (!pool->pf.discard_enabled)
2443 DMEMIT("ignore_discard");
2444 else if (pool->pf.discard_passdown)
2445 DMEMIT("discard_passdown");
2447 DMEMIT("no_discard_passdown");
2451 case STATUSTYPE_TABLE:
2452 DMEMIT("%s %s %lu %llu ",
2453 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2454 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2455 (unsigned long)pool->sectors_per_block,
2456 (unsigned long long)pt->low_water_blocks);
2457 emit_flags(&pt->requested_pf, result, sz, maxlen);
2466 static int pool_iterate_devices(struct dm_target *ti,
2467 iterate_devices_callout_fn fn, void *data)
2469 struct pool_c *pt = ti->private;
2471 return fn(ti, pt->data_dev, 0, ti->len, data);
2474 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2475 struct bio_vec *biovec, int max_size)
2477 struct pool_c *pt = ti->private;
2478 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2480 if (!q->merge_bvec_fn)
2483 bvm->bi_bdev = pt->data_dev->bdev;
2485 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2488 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
2490 struct pool *pool = pt->pool;
2491 struct queue_limits *data_limits;
2493 limits->max_discard_sectors = pool->sectors_per_block;
2496 * discard_granularity is just a hint, and not enforced.
2498 if (pt->adjusted_pf.discard_passdown) {
2499 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
2500 limits->discard_granularity = data_limits->discard_granularity;
2502 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
2505 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2507 struct pool_c *pt = ti->private;
2508 struct pool *pool = pt->pool;
2510 blk_limits_io_min(limits, 0);
2511 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2514 * pt->adjusted_pf is a staging area for the actual features to use.
2515 * They get transferred to the live pool in bind_control_target()
2516 * called from pool_preresume().
2518 if (!pt->adjusted_pf.discard_enabled)
2521 disable_passdown_if_not_supported(pt);
2523 set_discard_limits(pt, limits);
2526 static struct target_type pool_target = {
2527 .name = "thin-pool",
2528 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2529 DM_TARGET_IMMUTABLE,
2530 .version = {1, 6, 1},
2531 .module = THIS_MODULE,
2535 .postsuspend = pool_postsuspend,
2536 .preresume = pool_preresume,
2537 .resume = pool_resume,
2538 .message = pool_message,
2539 .status = pool_status,
2540 .merge = pool_merge,
2541 .iterate_devices = pool_iterate_devices,
2542 .io_hints = pool_io_hints,
2545 /*----------------------------------------------------------------
2546 * Thin target methods
2547 *--------------------------------------------------------------*/
2548 static void thin_dtr(struct dm_target *ti)
2550 struct thin_c *tc = ti->private;
2552 mutex_lock(&dm_thin_pool_table.mutex);
2554 __pool_dec(tc->pool);
2555 dm_pool_close_thin_device(tc->td);
2556 dm_put_device(ti, tc->pool_dev);
2558 dm_put_device(ti, tc->origin_dev);
2561 mutex_unlock(&dm_thin_pool_table.mutex);
2565 * Thin target parameters:
2567 * <pool_dev> <dev_id> [origin_dev]
2569 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2570 * dev_id: the internal device identifier
2571 * origin_dev: a device external to the pool that should act as the origin
2573 * If the pool device has discards disabled, they get disabled for the thin
2576 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2580 struct dm_dev *pool_dev, *origin_dev;
2581 struct mapped_device *pool_md;
2583 mutex_lock(&dm_thin_pool_table.mutex);
2585 if (argc != 2 && argc != 3) {
2586 ti->error = "Invalid argument count";
2591 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2593 ti->error = "Out of memory";
2599 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
2601 ti->error = "Error opening origin device";
2602 goto bad_origin_dev;
2604 tc->origin_dev = origin_dev;
2607 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2609 ti->error = "Error opening pool device";
2612 tc->pool_dev = pool_dev;
2614 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2615 ti->error = "Invalid device id";
2620 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2622 ti->error = "Couldn't get pool mapped device";
2627 tc->pool = __pool_table_lookup(pool_md);
2629 ti->error = "Couldn't find pool object";
2631 goto bad_pool_lookup;
2633 __pool_inc(tc->pool);
2635 if (get_pool_mode(tc->pool) == PM_FAIL) {
2636 ti->error = "Couldn't open thin device, Pool is in fail mode";
2640 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
2642 ti->error = "Couldn't open thin internal device";
2646 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
2650 ti->num_flush_bios = 1;
2651 ti->flush_supported = true;
2652 ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
2654 /* In case the pool supports discards, pass them on. */
2655 if (tc->pool->pf.discard_enabled) {
2656 ti->discards_supported = true;
2657 ti->num_discard_bios = 1;
2658 ti->discard_zeroes_data_unsupported = true;
2659 /* Discard bios must be split on a block boundary */
2660 ti->split_discard_bios = true;
2665 mutex_unlock(&dm_thin_pool_table.mutex);
2670 __pool_dec(tc->pool);
2674 dm_put_device(ti, tc->pool_dev);
2677 dm_put_device(ti, tc->origin_dev);
2681 mutex_unlock(&dm_thin_pool_table.mutex);
2686 static int thin_map(struct dm_target *ti, struct bio *bio)
2688 bio->bi_sector = dm_target_offset(ti, bio->bi_sector);
2690 return thin_bio_map(ti, bio);
2693 static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
2695 unsigned long flags;
2696 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2697 struct list_head work;
2698 struct dm_thin_new_mapping *m, *tmp;
2699 struct pool *pool = h->tc->pool;
2701 if (h->shared_read_entry) {
2702 INIT_LIST_HEAD(&work);
2703 dm_deferred_entry_dec(h->shared_read_entry, &work);
2705 spin_lock_irqsave(&pool->lock, flags);
2706 list_for_each_entry_safe(m, tmp, &work, list) {
2709 __maybe_add_mapping(m);
2711 spin_unlock_irqrestore(&pool->lock, flags);
2714 if (h->all_io_entry) {
2715 INIT_LIST_HEAD(&work);
2716 dm_deferred_entry_dec(h->all_io_entry, &work);
2717 if (!list_empty(&work)) {
2718 spin_lock_irqsave(&pool->lock, flags);
2719 list_for_each_entry_safe(m, tmp, &work, list)
2720 list_add(&m->list, &pool->prepared_discards);
2721 spin_unlock_irqrestore(&pool->lock, flags);
2729 static void thin_postsuspend(struct dm_target *ti)
2731 if (dm_noflush_suspending(ti))
2732 requeue_io((struct thin_c *)ti->private);
2736 * <nr mapped sectors> <highest mapped sector>
2738 static void thin_status(struct dm_target *ti, status_type_t type,
2739 unsigned status_flags, char *result, unsigned maxlen)
2743 dm_block_t mapped, highest;
2744 char buf[BDEVNAME_SIZE];
2745 struct thin_c *tc = ti->private;
2747 if (get_pool_mode(tc->pool) == PM_FAIL) {
2756 case STATUSTYPE_INFO:
2757 r = dm_thin_get_mapped_count(tc->td, &mapped);
2759 DMERR("dm_thin_get_mapped_count returned %d", r);
2763 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
2765 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
2769 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
2771 DMEMIT("%llu", ((highest + 1) *
2772 tc->pool->sectors_per_block) - 1);
2777 case STATUSTYPE_TABLE:
2779 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
2780 (unsigned long) tc->dev_id);
2782 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
2793 static int thin_iterate_devices(struct dm_target *ti,
2794 iterate_devices_callout_fn fn, void *data)
2797 struct thin_c *tc = ti->private;
2798 struct pool *pool = tc->pool;
2801 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2802 * we follow a more convoluted path through to the pool's target.
2805 return 0; /* nothing is bound */
2807 blocks = pool->ti->len;
2808 (void) sector_div(blocks, pool->sectors_per_block);
2810 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
2815 static struct target_type thin_target = {
2817 .version = {1, 7, 1},
2818 .module = THIS_MODULE,
2822 .end_io = thin_endio,
2823 .postsuspend = thin_postsuspend,
2824 .status = thin_status,
2825 .iterate_devices = thin_iterate_devices,
2828 /*----------------------------------------------------------------*/
2830 static int __init dm_thin_init(void)
2836 r = dm_register_target(&thin_target);
2840 r = dm_register_target(&pool_target);
2842 goto bad_pool_target;
2846 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
2847 if (!_new_mapping_cache)
2848 goto bad_new_mapping_cache;
2852 bad_new_mapping_cache:
2853 dm_unregister_target(&pool_target);
2855 dm_unregister_target(&thin_target);
2860 static void dm_thin_exit(void)
2862 dm_unregister_target(&thin_target);
2863 dm_unregister_target(&pool_target);
2865 kmem_cache_destroy(_new_mapping_cache);
2868 module_init(dm_thin_init);
2869 module_exit(dm_thin_exit);
2871 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
2872 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2873 MODULE_LICENSE("GPL");