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/log2.h>
15 #include <linux/list.h>
16 #include <linux/rculist.h>
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
20 #include <linux/rbtree.h>
22 #define DM_MSG_PREFIX "thin"
27 #define ENDIO_HOOK_POOL_SIZE 1024
28 #define MAPPING_POOL_SIZE 1024
29 #define COMMIT_PERIOD HZ
30 #define NO_SPACE_TIMEOUT_SECS 60
32 static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
34 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
35 "A percentage of time allocated for copy on write");
38 * The block size of the device holding pool data must be
39 * between 64KB and 1GB.
41 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
42 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
45 * Device id is restricted to 24 bits.
47 #define MAX_DEV_ID ((1 << 24) - 1)
50 * How do we handle breaking sharing of data blocks?
51 * =================================================
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
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.
63 * Let's say we write to a shared block in what was the origin. The
66 * i) plug io further to this physical block. (see bio_prison code).
68 * ii) quiesce any read io to that shared data block. Obviously
69 * including all devices that share this block. (see dm_deferred_set code)
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).
74 * iv) insert the new mapping into the origin's btree
75 * (process_prepared_mapping). 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.
82 * v) unplug io to this physical block, including the io that triggered
83 * the breaking of sharing.
85 * Steps (ii) and (iii) occur in parallel.
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:
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.
95 * - The snap mapping still points to the old block. As it would after
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.
107 /*----------------------------------------------------------------*/
112 static void build_data_key(struct dm_thin_device *td,
113 dm_block_t b, struct dm_cell_key *key)
116 key->dev = dm_thin_dev_id(td);
120 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
121 struct dm_cell_key *key)
124 key->dev = dm_thin_dev_id(td);
128 /*----------------------------------------------------------------*/
130 #define THROTTLE_THRESHOLD (1 * HZ)
133 struct rw_semaphore lock;
134 unsigned long threshold;
135 bool throttle_applied;
138 static void throttle_init(struct throttle *t)
140 init_rwsem(&t->lock);
141 t->throttle_applied = false;
144 static void throttle_work_start(struct throttle *t)
146 t->threshold = jiffies + THROTTLE_THRESHOLD;
149 static void throttle_work_update(struct throttle *t)
151 if (!t->throttle_applied && jiffies > t->threshold) {
152 down_write(&t->lock);
153 t->throttle_applied = true;
157 static void throttle_work_complete(struct throttle *t)
159 if (t->throttle_applied) {
160 t->throttle_applied = false;
165 static void throttle_lock(struct throttle *t)
170 static void throttle_unlock(struct throttle *t)
175 /*----------------------------------------------------------------*/
178 * A pool device ties together a metadata device and a data device. It
179 * also provides the interface for creating and destroying internal
182 struct dm_thin_new_mapping;
185 * The pool runs in 4 modes. Ordered in degraded order for comparisons.
188 PM_WRITE, /* metadata may be changed */
189 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
190 PM_READ_ONLY, /* metadata may not be changed */
191 PM_FAIL, /* all I/O fails */
194 struct pool_features {
197 bool zero_new_blocks:1;
198 bool discard_enabled:1;
199 bool discard_passdown:1;
200 bool error_if_no_space:1;
204 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
205 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
208 struct list_head list;
209 struct dm_target *ti; /* Only set if a pool target is bound */
211 struct mapped_device *pool_md;
212 struct block_device *md_dev;
213 struct dm_pool_metadata *pmd;
215 dm_block_t low_water_blocks;
216 uint32_t sectors_per_block;
217 int sectors_per_block_shift;
219 struct pool_features pf;
220 bool low_water_triggered:1; /* A dm event has been sent */
222 struct dm_bio_prison *prison;
223 struct dm_kcopyd_client *copier;
225 struct workqueue_struct *wq;
226 struct throttle throttle;
227 struct work_struct worker;
228 struct delayed_work waker;
229 struct delayed_work no_space_timeout;
231 unsigned long last_commit_jiffies;
235 struct bio_list deferred_flush_bios;
236 struct list_head prepared_mappings;
237 struct list_head prepared_discards;
238 struct list_head active_thins;
240 struct dm_deferred_set *shared_read_ds;
241 struct dm_deferred_set *all_io_ds;
243 struct dm_thin_new_mapping *next_mapping;
244 mempool_t *mapping_pool;
246 process_bio_fn process_bio;
247 process_bio_fn process_discard;
249 process_mapping_fn process_prepared_mapping;
250 process_mapping_fn process_prepared_discard;
253 static enum pool_mode get_pool_mode(struct pool *pool);
254 static void metadata_operation_failed(struct pool *pool, const char *op, int r);
257 * Target context for a pool.
260 struct dm_target *ti;
262 struct dm_dev *data_dev;
263 struct dm_dev *metadata_dev;
264 struct dm_target_callbacks callbacks;
266 dm_block_t low_water_blocks;
267 struct pool_features requested_pf; /* Features requested during table load */
268 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
272 * Target context for a thin.
275 struct list_head list;
276 struct dm_dev *pool_dev;
277 struct dm_dev *origin_dev;
278 sector_t origin_size;
282 struct dm_thin_device *td;
285 struct bio_list deferred_bio_list;
286 struct bio_list retry_on_resume_list;
287 struct rb_root sort_bio_list; /* sorted list of deferred bios */
290 * Ensures the thin is not destroyed until the worker has finished
291 * iterating the active_thins list.
294 struct completion can_destroy;
297 /*----------------------------------------------------------------*/
300 * wake_worker() is used when new work is queued and when pool_resume is
301 * ready to continue deferred IO processing.
303 static void wake_worker(struct pool *pool)
305 queue_work(pool->wq, &pool->worker);
308 /*----------------------------------------------------------------*/
310 static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
311 struct dm_bio_prison_cell **cell_result)
314 struct dm_bio_prison_cell *cell_prealloc;
317 * Allocate a cell from the prison's mempool.
318 * This might block but it can't fail.
320 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
322 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
325 * We reused an old cell; we can get rid of
328 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
333 static void cell_release(struct pool *pool,
334 struct dm_bio_prison_cell *cell,
335 struct bio_list *bios)
337 dm_cell_release(pool->prison, cell, bios);
338 dm_bio_prison_free_cell(pool->prison, cell);
341 static void cell_release_no_holder(struct pool *pool,
342 struct dm_bio_prison_cell *cell,
343 struct bio_list *bios)
345 dm_cell_release_no_holder(pool->prison, cell, bios);
346 dm_bio_prison_free_cell(pool->prison, cell);
349 static void cell_defer_no_holder_no_free(struct thin_c *tc,
350 struct dm_bio_prison_cell *cell)
352 struct pool *pool = tc->pool;
355 spin_lock_irqsave(&tc->lock, flags);
356 dm_cell_release_no_holder(pool->prison, cell, &tc->deferred_bio_list);
357 spin_unlock_irqrestore(&tc->lock, flags);
362 static void cell_error_with_code(struct pool *pool,
363 struct dm_bio_prison_cell *cell, int error_code)
365 dm_cell_error(pool->prison, cell, error_code);
366 dm_bio_prison_free_cell(pool->prison, cell);
369 static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
371 cell_error_with_code(pool, cell, -EIO);
374 /*----------------------------------------------------------------*/
377 * A global list of pools that uses a struct mapped_device as a key.
379 static struct dm_thin_pool_table {
381 struct list_head pools;
382 } dm_thin_pool_table;
384 static void pool_table_init(void)
386 mutex_init(&dm_thin_pool_table.mutex);
387 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
390 static void __pool_table_insert(struct pool *pool)
392 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
393 list_add(&pool->list, &dm_thin_pool_table.pools);
396 static void __pool_table_remove(struct pool *pool)
398 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
399 list_del(&pool->list);
402 static struct pool *__pool_table_lookup(struct mapped_device *md)
404 struct pool *pool = NULL, *tmp;
406 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
408 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
409 if (tmp->pool_md == md) {
418 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
420 struct pool *pool = NULL, *tmp;
422 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
424 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
425 if (tmp->md_dev == md_dev) {
434 /*----------------------------------------------------------------*/
436 struct dm_thin_endio_hook {
438 struct dm_deferred_entry *shared_read_entry;
439 struct dm_deferred_entry *all_io_entry;
440 struct dm_thin_new_mapping *overwrite_mapping;
441 struct rb_node rb_node;
444 static void requeue_bio_list(struct thin_c *tc, struct bio_list *master)
447 struct bio_list bios;
450 bio_list_init(&bios);
452 spin_lock_irqsave(&tc->lock, flags);
453 bio_list_merge(&bios, master);
454 bio_list_init(master);
455 spin_unlock_irqrestore(&tc->lock, flags);
457 while ((bio = bio_list_pop(&bios)))
458 bio_endio(bio, DM_ENDIO_REQUEUE);
461 static void requeue_io(struct thin_c *tc)
463 requeue_bio_list(tc, &tc->deferred_bio_list);
464 requeue_bio_list(tc, &tc->retry_on_resume_list);
467 static void error_thin_retry_list(struct thin_c *tc)
471 struct bio_list bios;
473 bio_list_init(&bios);
475 spin_lock_irqsave(&tc->lock, flags);
476 bio_list_merge(&bios, &tc->retry_on_resume_list);
477 bio_list_init(&tc->retry_on_resume_list);
478 spin_unlock_irqrestore(&tc->lock, flags);
480 while ((bio = bio_list_pop(&bios)))
484 static void error_retry_list(struct pool *pool)
489 list_for_each_entry_rcu(tc, &pool->active_thins, list)
490 error_thin_retry_list(tc);
495 * This section of code contains the logic for processing a thin device's IO.
496 * Much of the code depends on pool object resources (lists, workqueues, etc)
497 * but most is exclusively called from the thin target rather than the thin-pool
501 static bool block_size_is_power_of_two(struct pool *pool)
503 return pool->sectors_per_block_shift >= 0;
506 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
508 struct pool *pool = tc->pool;
509 sector_t block_nr = bio->bi_iter.bi_sector;
511 if (block_size_is_power_of_two(pool))
512 block_nr >>= pool->sectors_per_block_shift;
514 (void) sector_div(block_nr, pool->sectors_per_block);
519 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
521 struct pool *pool = tc->pool;
522 sector_t bi_sector = bio->bi_iter.bi_sector;
524 bio->bi_bdev = tc->pool_dev->bdev;
525 if (block_size_is_power_of_two(pool))
526 bio->bi_iter.bi_sector =
527 (block << pool->sectors_per_block_shift) |
528 (bi_sector & (pool->sectors_per_block - 1));
530 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
531 sector_div(bi_sector, pool->sectors_per_block);
534 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
536 bio->bi_bdev = tc->origin_dev->bdev;
539 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
541 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
542 dm_thin_changed_this_transaction(tc->td);
545 static void inc_all_io_entry(struct pool *pool, struct bio *bio)
547 struct dm_thin_endio_hook *h;
549 if (bio->bi_rw & REQ_DISCARD)
552 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
553 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
556 static void issue(struct thin_c *tc, struct bio *bio)
558 struct pool *pool = tc->pool;
561 if (!bio_triggers_commit(tc, bio)) {
562 generic_make_request(bio);
567 * Complete bio with an error if earlier I/O caused changes to
568 * the metadata that can't be committed e.g, due to I/O errors
569 * on the metadata device.
571 if (dm_thin_aborted_changes(tc->td)) {
577 * Batch together any bios that trigger commits and then issue a
578 * single commit for them in process_deferred_bios().
580 spin_lock_irqsave(&pool->lock, flags);
581 bio_list_add(&pool->deferred_flush_bios, bio);
582 spin_unlock_irqrestore(&pool->lock, flags);
585 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
587 remap_to_origin(tc, bio);
591 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
594 remap(tc, bio, block);
598 /*----------------------------------------------------------------*/
601 * Bio endio functions.
603 struct dm_thin_new_mapping {
604 struct list_head list;
607 bool definitely_not_shared:1;
610 * Track quiescing, copying and zeroing preparation actions. When this
611 * counter hits zero the block is prepared and can be inserted into the
614 atomic_t prepare_actions;
618 dm_block_t virt_block;
619 dm_block_t data_block;
620 struct dm_bio_prison_cell *cell, *cell2;
623 * If the bio covers the whole area of a block then we can avoid
624 * zeroing or copying. Instead this bio is hooked. The bio will
625 * still be in the cell, so care has to be taken to avoid issuing
629 bio_end_io_t *saved_bi_end_io;
632 static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
634 struct pool *pool = m->tc->pool;
636 if (atomic_dec_and_test(&m->prepare_actions)) {
637 list_add_tail(&m->list, &pool->prepared_mappings);
642 static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
645 struct pool *pool = m->tc->pool;
647 spin_lock_irqsave(&pool->lock, flags);
648 __complete_mapping_preparation(m);
649 spin_unlock_irqrestore(&pool->lock, flags);
652 static void copy_complete(int read_err, unsigned long write_err, void *context)
654 struct dm_thin_new_mapping *m = context;
656 m->err = read_err || write_err ? -EIO : 0;
657 complete_mapping_preparation(m);
660 static void overwrite_endio(struct bio *bio, int err)
662 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
663 struct dm_thin_new_mapping *m = h->overwrite_mapping;
666 complete_mapping_preparation(m);
669 /*----------------------------------------------------------------*/
676 * Prepared mapping jobs.
680 * This sends the bios in the cell back to the deferred_bios list.
682 static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
684 struct pool *pool = tc->pool;
687 spin_lock_irqsave(&tc->lock, flags);
688 cell_release(pool, cell, &tc->deferred_bio_list);
689 spin_unlock_irqrestore(&tc->lock, flags);
695 * Same as cell_defer above, except it omits the original holder of the cell.
697 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
699 struct pool *pool = tc->pool;
702 spin_lock_irqsave(&tc->lock, flags);
703 cell_release_no_holder(pool, cell, &tc->deferred_bio_list);
704 spin_unlock_irqrestore(&tc->lock, flags);
709 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
712 m->bio->bi_end_io = m->saved_bi_end_io;
713 atomic_inc(&m->bio->bi_remaining);
715 cell_error(m->tc->pool, m->cell);
717 mempool_free(m, m->tc->pool->mapping_pool);
720 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
722 struct thin_c *tc = m->tc;
723 struct pool *pool = tc->pool;
729 bio->bi_end_io = m->saved_bi_end_io;
730 atomic_inc(&bio->bi_remaining);
734 cell_error(pool, m->cell);
739 * Commit the prepared block into the mapping btree.
740 * Any I/O for this block arriving after this point will get
741 * remapped to it directly.
743 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
745 metadata_operation_failed(pool, "dm_thin_insert_block", r);
746 cell_error(pool, m->cell);
751 * Release any bios held while the block was being provisioned.
752 * If we are processing a write bio that completely covers the block,
753 * we already processed it so can ignore it now when processing
754 * the bios in the cell.
757 cell_defer_no_holder(tc, m->cell);
760 cell_defer(tc, m->cell);
764 mempool_free(m, pool->mapping_pool);
767 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
769 struct thin_c *tc = m->tc;
771 bio_io_error(m->bio);
772 cell_defer_no_holder(tc, m->cell);
773 cell_defer_no_holder(tc, m->cell2);
774 mempool_free(m, tc->pool->mapping_pool);
777 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
779 struct thin_c *tc = m->tc;
781 inc_all_io_entry(tc->pool, m->bio);
782 cell_defer_no_holder(tc, m->cell);
783 cell_defer_no_holder(tc, m->cell2);
786 if (m->definitely_not_shared)
787 remap_and_issue(tc, m->bio, m->data_block);
790 if (dm_pool_block_is_used(tc->pool->pmd, m->data_block, &used) || used)
791 bio_endio(m->bio, 0);
793 remap_and_issue(tc, m->bio, m->data_block);
796 bio_endio(m->bio, 0);
798 mempool_free(m, tc->pool->mapping_pool);
801 static void process_prepared_discard(struct dm_thin_new_mapping *m)
804 struct thin_c *tc = m->tc;
806 r = dm_thin_remove_block(tc->td, m->virt_block);
808 DMERR_LIMIT("dm_thin_remove_block() failed");
810 process_prepared_discard_passdown(m);
813 static void process_prepared(struct pool *pool, struct list_head *head,
814 process_mapping_fn *fn)
817 struct list_head maps;
818 struct dm_thin_new_mapping *m, *tmp;
820 INIT_LIST_HEAD(&maps);
821 spin_lock_irqsave(&pool->lock, flags);
822 list_splice_init(head, &maps);
823 spin_unlock_irqrestore(&pool->lock, flags);
825 list_for_each_entry_safe(m, tmp, &maps, list)
832 static int io_overlaps_block(struct pool *pool, struct bio *bio)
834 return bio->bi_iter.bi_size ==
835 (pool->sectors_per_block << SECTOR_SHIFT);
838 static int io_overwrites_block(struct pool *pool, struct bio *bio)
840 return (bio_data_dir(bio) == WRITE) &&
841 io_overlaps_block(pool, bio);
844 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
847 *save = bio->bi_end_io;
851 static int ensure_next_mapping(struct pool *pool)
853 if (pool->next_mapping)
856 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
858 return pool->next_mapping ? 0 : -ENOMEM;
861 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
863 struct dm_thin_new_mapping *m = pool->next_mapping;
865 BUG_ON(!pool->next_mapping);
867 memset(m, 0, sizeof(struct dm_thin_new_mapping));
868 INIT_LIST_HEAD(&m->list);
871 pool->next_mapping = NULL;
876 static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
877 sector_t begin, sector_t end)
880 struct dm_io_region to;
882 to.bdev = tc->pool_dev->bdev;
884 to.count = end - begin;
886 r = dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
888 DMERR_LIMIT("dm_kcopyd_zero() failed");
889 copy_complete(1, 1, m);
893 static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
894 dm_block_t data_block,
895 struct dm_thin_new_mapping *m)
897 struct pool *pool = tc->pool;
898 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
900 h->overwrite_mapping = m;
902 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
903 inc_all_io_entry(pool, bio);
904 remap_and_issue(tc, bio, data_block);
908 * A partial copy also needs to zero the uncopied region.
910 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
911 struct dm_dev *origin, dm_block_t data_origin,
912 dm_block_t data_dest,
913 struct dm_bio_prison_cell *cell, struct bio *bio,
917 struct pool *pool = tc->pool;
918 struct dm_thin_new_mapping *m = get_next_mapping(pool);
921 m->virt_block = virt_block;
922 m->data_block = data_dest;
926 * quiesce action + copy action + an extra reference held for the
927 * duration of this function (we may need to inc later for a
930 atomic_set(&m->prepare_actions, 3);
932 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
933 complete_mapping_preparation(m); /* already quiesced */
936 * IO to pool_dev remaps to the pool target's data_dev.
938 * If the whole block of data is being overwritten, we can issue the
939 * bio immediately. Otherwise we use kcopyd to clone the data first.
941 if (io_overwrites_block(pool, bio))
942 remap_and_issue_overwrite(tc, bio, data_dest, m);
944 struct dm_io_region from, to;
946 from.bdev = origin->bdev;
947 from.sector = data_origin * pool->sectors_per_block;
950 to.bdev = tc->pool_dev->bdev;
951 to.sector = data_dest * pool->sectors_per_block;
954 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
955 0, copy_complete, m);
957 DMERR_LIMIT("dm_kcopyd_copy() failed");
958 copy_complete(1, 1, m);
961 * We allow the zero to be issued, to simplify the
962 * error path. Otherwise we'd need to start
963 * worrying about decrementing the prepare_actions
969 * Do we need to zero a tail region?
971 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
972 atomic_inc(&m->prepare_actions);
974 data_dest * pool->sectors_per_block + len,
975 (data_dest + 1) * pool->sectors_per_block);
979 complete_mapping_preparation(m); /* drop our ref */
982 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
983 dm_block_t data_origin, dm_block_t data_dest,
984 struct dm_bio_prison_cell *cell, struct bio *bio)
986 schedule_copy(tc, virt_block, tc->pool_dev,
987 data_origin, data_dest, cell, bio,
988 tc->pool->sectors_per_block);
991 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
992 dm_block_t data_block, struct dm_bio_prison_cell *cell,
995 struct pool *pool = tc->pool;
996 struct dm_thin_new_mapping *m = get_next_mapping(pool);
998 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
1000 m->virt_block = virt_block;
1001 m->data_block = data_block;
1005 * If the whole block of data is being overwritten or we are not
1006 * zeroing pre-existing data, we can issue the bio immediately.
1007 * Otherwise we use kcopyd to zero the data first.
1009 if (!pool->pf.zero_new_blocks)
1010 process_prepared_mapping(m);
1012 else if (io_overwrites_block(pool, bio))
1013 remap_and_issue_overwrite(tc, bio, data_block, m);
1017 data_block * pool->sectors_per_block,
1018 (data_block + 1) * pool->sectors_per_block);
1021 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1022 dm_block_t data_dest,
1023 struct dm_bio_prison_cell *cell, struct bio *bio)
1025 struct pool *pool = tc->pool;
1026 sector_t virt_block_begin = virt_block * pool->sectors_per_block;
1027 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
1029 if (virt_block_end <= tc->origin_size)
1030 schedule_copy(tc, virt_block, tc->origin_dev,
1031 virt_block, data_dest, cell, bio,
1032 pool->sectors_per_block);
1034 else if (virt_block_begin < tc->origin_size)
1035 schedule_copy(tc, virt_block, tc->origin_dev,
1036 virt_block, data_dest, cell, bio,
1037 tc->origin_size - virt_block_begin);
1040 schedule_zero(tc, virt_block, data_dest, cell, bio);
1044 * A non-zero return indicates read_only or fail_io mode.
1045 * Many callers don't care about the return value.
1047 static int commit(struct pool *pool)
1051 if (get_pool_mode(pool) >= PM_READ_ONLY)
1054 r = dm_pool_commit_metadata(pool->pmd);
1056 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
1061 static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
1063 unsigned long flags;
1065 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1066 DMWARN("%s: reached low water mark for data device: sending event.",
1067 dm_device_name(pool->pool_md));
1068 spin_lock_irqsave(&pool->lock, flags);
1069 pool->low_water_triggered = true;
1070 spin_unlock_irqrestore(&pool->lock, flags);
1071 dm_table_event(pool->ti->table);
1075 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
1077 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1080 dm_block_t free_blocks;
1081 struct pool *pool = tc->pool;
1083 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
1086 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1088 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1092 check_low_water_mark(pool, free_blocks);
1096 * Try to commit to see if that will free up some
1103 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1105 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1110 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1115 r = dm_pool_alloc_data_block(pool->pmd, result);
1117 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1125 * If we have run out of space, queue bios until the device is
1126 * resumed, presumably after having been reloaded with more space.
1128 static void retry_on_resume(struct bio *bio)
1130 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1131 struct thin_c *tc = h->tc;
1132 unsigned long flags;
1134 spin_lock_irqsave(&tc->lock, flags);
1135 bio_list_add(&tc->retry_on_resume_list, bio);
1136 spin_unlock_irqrestore(&tc->lock, flags);
1139 static int should_error_unserviceable_bio(struct pool *pool)
1141 enum pool_mode m = get_pool_mode(pool);
1145 /* Shouldn't get here */
1146 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1149 case PM_OUT_OF_DATA_SPACE:
1150 return pool->pf.error_if_no_space ? -ENOSPC : 0;
1156 /* Shouldn't get here */
1157 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1162 static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1164 int error = should_error_unserviceable_bio(pool);
1167 bio_endio(bio, error);
1169 retry_on_resume(bio);
1172 static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1175 struct bio_list bios;
1178 error = should_error_unserviceable_bio(pool);
1180 cell_error_with_code(pool, cell, error);
1184 bio_list_init(&bios);
1185 cell_release(pool, cell, &bios);
1187 error = should_error_unserviceable_bio(pool);
1189 while ((bio = bio_list_pop(&bios)))
1190 bio_endio(bio, error);
1192 while ((bio = bio_list_pop(&bios)))
1193 retry_on_resume(bio);
1196 static void process_discard(struct thin_c *tc, struct bio *bio)
1199 struct pool *pool = tc->pool;
1200 struct dm_bio_prison_cell *cell, *cell2;
1201 struct dm_cell_key key, key2;
1202 dm_block_t block = get_bio_block(tc, bio);
1203 struct dm_thin_lookup_result lookup_result;
1204 struct dm_thin_new_mapping *m;
1206 build_virtual_key(tc->td, block, &key);
1207 if (bio_detain(tc->pool, &key, bio, &cell))
1210 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1214 * Check nobody is fiddling with this pool block. This can
1215 * happen if someone's in the process of breaking sharing
1218 build_data_key(tc->td, lookup_result.block, &key2);
1219 if (bio_detain(tc->pool, &key2, bio, &cell2)) {
1220 cell_defer_no_holder(tc, cell);
1224 if (io_overlaps_block(pool, bio)) {
1226 * IO may still be going to the destination block. We must
1227 * quiesce before we can do the removal.
1229 m = get_next_mapping(pool);
1231 m->pass_discard = pool->pf.discard_passdown;
1232 m->definitely_not_shared = !lookup_result.shared;
1233 m->virt_block = block;
1234 m->data_block = lookup_result.block;
1239 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1240 pool->process_prepared_discard(m);
1243 inc_all_io_entry(pool, bio);
1244 cell_defer_no_holder(tc, cell);
1245 cell_defer_no_holder(tc, cell2);
1248 * The DM core makes sure that the discard doesn't span
1249 * a block boundary. So we submit the discard of a
1250 * partial block appropriately.
1252 if ((!lookup_result.shared) && pool->pf.discard_passdown)
1253 remap_and_issue(tc, bio, lookup_result.block);
1261 * It isn't provisioned, just forget it.
1263 cell_defer_no_holder(tc, cell);
1268 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1270 cell_defer_no_holder(tc, cell);
1276 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1277 struct dm_cell_key *key,
1278 struct dm_thin_lookup_result *lookup_result,
1279 struct dm_bio_prison_cell *cell)
1282 dm_block_t data_block;
1283 struct pool *pool = tc->pool;
1285 r = alloc_data_block(tc, &data_block);
1288 schedule_internal_copy(tc, block, lookup_result->block,
1289 data_block, cell, bio);
1293 retry_bios_on_resume(pool, cell);
1297 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1299 cell_error(pool, cell);
1304 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1306 struct dm_thin_lookup_result *lookup_result)
1308 struct dm_bio_prison_cell *cell;
1309 struct pool *pool = tc->pool;
1310 struct dm_cell_key key;
1313 * If cell is already occupied, then sharing is already in the process
1314 * of being broken so we have nothing further to do here.
1316 build_data_key(tc->td, lookup_result->block, &key);
1317 if (bio_detain(pool, &key, bio, &cell))
1320 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size)
1321 break_sharing(tc, bio, block, &key, lookup_result, cell);
1323 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1325 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1326 inc_all_io_entry(pool, bio);
1327 cell_defer_no_holder(tc, cell);
1329 remap_and_issue(tc, bio, lookup_result->block);
1333 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1334 struct dm_bio_prison_cell *cell)
1337 dm_block_t data_block;
1338 struct pool *pool = tc->pool;
1341 * Remap empty bios (flushes) immediately, without provisioning.
1343 if (!bio->bi_iter.bi_size) {
1344 inc_all_io_entry(pool, bio);
1345 cell_defer_no_holder(tc, cell);
1347 remap_and_issue(tc, bio, 0);
1352 * Fill read bios with zeroes and complete them immediately.
1354 if (bio_data_dir(bio) == READ) {
1356 cell_defer_no_holder(tc, cell);
1361 r = alloc_data_block(tc, &data_block);
1365 schedule_external_copy(tc, block, data_block, cell, bio);
1367 schedule_zero(tc, block, data_block, cell, bio);
1371 retry_bios_on_resume(pool, cell);
1375 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1377 cell_error(pool, cell);
1382 static void process_bio(struct thin_c *tc, struct bio *bio)
1385 struct pool *pool = tc->pool;
1386 dm_block_t block = get_bio_block(tc, bio);
1387 struct dm_bio_prison_cell *cell;
1388 struct dm_cell_key key;
1389 struct dm_thin_lookup_result lookup_result;
1392 * If cell is already occupied, then the block is already
1393 * being provisioned so we have nothing further to do here.
1395 build_virtual_key(tc->td, block, &key);
1396 if (bio_detain(pool, &key, bio, &cell))
1399 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1402 if (lookup_result.shared) {
1403 process_shared_bio(tc, bio, block, &lookup_result);
1404 cell_defer_no_holder(tc, cell); /* FIXME: pass this cell into process_shared? */
1406 inc_all_io_entry(pool, bio);
1407 cell_defer_no_holder(tc, cell);
1409 remap_and_issue(tc, bio, lookup_result.block);
1414 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1415 inc_all_io_entry(pool, bio);
1416 cell_defer_no_holder(tc, cell);
1418 if (bio_end_sector(bio) <= tc->origin_size)
1419 remap_to_origin_and_issue(tc, bio);
1421 else if (bio->bi_iter.bi_sector < tc->origin_size) {
1423 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
1424 remap_to_origin_and_issue(tc, bio);
1431 provision_block(tc, bio, block, cell);
1435 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1437 cell_defer_no_holder(tc, cell);
1443 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1446 int rw = bio_data_dir(bio);
1447 dm_block_t block = get_bio_block(tc, bio);
1448 struct dm_thin_lookup_result lookup_result;
1450 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1453 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size)
1454 handle_unserviceable_bio(tc->pool, bio);
1456 inc_all_io_entry(tc->pool, bio);
1457 remap_and_issue(tc, bio, lookup_result.block);
1463 handle_unserviceable_bio(tc->pool, bio);
1467 if (tc->origin_dev) {
1468 inc_all_io_entry(tc->pool, bio);
1469 remap_to_origin_and_issue(tc, bio);
1478 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1485 static void process_bio_success(struct thin_c *tc, struct bio *bio)
1490 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1496 * FIXME: should we also commit due to size of transaction, measured in
1499 static int need_commit_due_to_time(struct pool *pool)
1501 return jiffies < pool->last_commit_jiffies ||
1502 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1505 #define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
1506 #define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
1508 static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
1510 struct rb_node **rbp, *parent;
1511 struct dm_thin_endio_hook *pbd;
1512 sector_t bi_sector = bio->bi_iter.bi_sector;
1514 rbp = &tc->sort_bio_list.rb_node;
1518 pbd = thin_pbd(parent);
1520 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
1521 rbp = &(*rbp)->rb_left;
1523 rbp = &(*rbp)->rb_right;
1526 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1527 rb_link_node(&pbd->rb_node, parent, rbp);
1528 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
1531 static void __extract_sorted_bios(struct thin_c *tc)
1533 struct rb_node *node;
1534 struct dm_thin_endio_hook *pbd;
1537 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
1538 pbd = thin_pbd(node);
1539 bio = thin_bio(pbd);
1541 bio_list_add(&tc->deferred_bio_list, bio);
1542 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
1545 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
1548 static void __sort_thin_deferred_bios(struct thin_c *tc)
1551 struct bio_list bios;
1553 bio_list_init(&bios);
1554 bio_list_merge(&bios, &tc->deferred_bio_list);
1555 bio_list_init(&tc->deferred_bio_list);
1557 /* Sort deferred_bio_list using rb-tree */
1558 while ((bio = bio_list_pop(&bios)))
1559 __thin_bio_rb_add(tc, bio);
1562 * Transfer the sorted bios in sort_bio_list back to
1563 * deferred_bio_list to allow lockless submission of
1566 __extract_sorted_bios(tc);
1569 static void process_thin_deferred_bios(struct thin_c *tc)
1571 struct pool *pool = tc->pool;
1572 unsigned long flags;
1574 struct bio_list bios;
1575 struct blk_plug plug;
1578 if (tc->requeue_mode) {
1579 requeue_bio_list(tc, &tc->deferred_bio_list);
1583 bio_list_init(&bios);
1585 spin_lock_irqsave(&tc->lock, flags);
1587 if (bio_list_empty(&tc->deferred_bio_list)) {
1588 spin_unlock_irqrestore(&tc->lock, flags);
1592 __sort_thin_deferred_bios(tc);
1594 bio_list_merge(&bios, &tc->deferred_bio_list);
1595 bio_list_init(&tc->deferred_bio_list);
1597 spin_unlock_irqrestore(&tc->lock, flags);
1599 blk_start_plug(&plug);
1600 while ((bio = bio_list_pop(&bios))) {
1602 * If we've got no free new_mapping structs, and processing
1603 * this bio might require one, we pause until there are some
1604 * prepared mappings to process.
1606 if (ensure_next_mapping(pool)) {
1607 spin_lock_irqsave(&tc->lock, flags);
1608 bio_list_add(&tc->deferred_bio_list, bio);
1609 bio_list_merge(&tc->deferred_bio_list, &bios);
1610 spin_unlock_irqrestore(&tc->lock, flags);
1614 if (bio->bi_rw & REQ_DISCARD)
1615 pool->process_discard(tc, bio);
1617 pool->process_bio(tc, bio);
1619 if ((count++ & 127) == 0) {
1620 throttle_work_update(&pool->throttle);
1621 dm_pool_issue_prefetches(pool->pmd);
1624 blk_finish_plug(&plug);
1627 static void thin_get(struct thin_c *tc);
1628 static void thin_put(struct thin_c *tc);
1631 * We can't hold rcu_read_lock() around code that can block. So we
1632 * find a thin with the rcu lock held; bump a refcount; then drop
1635 static struct thin_c *get_first_thin(struct pool *pool)
1637 struct thin_c *tc = NULL;
1640 if (!list_empty(&pool->active_thins)) {
1641 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
1649 static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
1651 struct thin_c *old_tc = tc;
1654 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
1666 static void process_deferred_bios(struct pool *pool)
1668 unsigned long flags;
1670 struct bio_list bios;
1673 tc = get_first_thin(pool);
1675 process_thin_deferred_bios(tc);
1676 tc = get_next_thin(pool, tc);
1680 * If there are any deferred flush bios, we must commit
1681 * the metadata before issuing them.
1683 bio_list_init(&bios);
1684 spin_lock_irqsave(&pool->lock, flags);
1685 bio_list_merge(&bios, &pool->deferred_flush_bios);
1686 bio_list_init(&pool->deferred_flush_bios);
1687 spin_unlock_irqrestore(&pool->lock, flags);
1689 if (bio_list_empty(&bios) &&
1690 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
1694 while ((bio = bio_list_pop(&bios)))
1698 pool->last_commit_jiffies = jiffies;
1700 while ((bio = bio_list_pop(&bios)))
1701 generic_make_request(bio);
1704 static void do_worker(struct work_struct *ws)
1706 struct pool *pool = container_of(ws, struct pool, worker);
1708 throttle_work_start(&pool->throttle);
1709 dm_pool_issue_prefetches(pool->pmd);
1710 throttle_work_update(&pool->throttle);
1711 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1712 throttle_work_update(&pool->throttle);
1713 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1714 throttle_work_update(&pool->throttle);
1715 process_deferred_bios(pool);
1716 throttle_work_complete(&pool->throttle);
1720 * We want to commit periodically so that not too much
1721 * unwritten data builds up.
1723 static void do_waker(struct work_struct *ws)
1725 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1727 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1731 * We're holding onto IO to allow userland time to react. After the
1732 * timeout either the pool will have been resized (and thus back in
1733 * PM_WRITE mode), or we degrade to PM_READ_ONLY and start erroring IO.
1735 static void do_no_space_timeout(struct work_struct *ws)
1737 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
1740 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space)
1741 set_pool_mode(pool, PM_READ_ONLY);
1744 /*----------------------------------------------------------------*/
1747 struct work_struct worker;
1748 struct completion complete;
1751 static struct pool_work *to_pool_work(struct work_struct *ws)
1753 return container_of(ws, struct pool_work, worker);
1756 static void pool_work_complete(struct pool_work *pw)
1758 complete(&pw->complete);
1761 static void pool_work_wait(struct pool_work *pw, struct pool *pool,
1762 void (*fn)(struct work_struct *))
1764 INIT_WORK_ONSTACK(&pw->worker, fn);
1765 init_completion(&pw->complete);
1766 queue_work(pool->wq, &pw->worker);
1767 wait_for_completion(&pw->complete);
1770 /*----------------------------------------------------------------*/
1772 struct noflush_work {
1773 struct pool_work pw;
1777 static struct noflush_work *to_noflush(struct work_struct *ws)
1779 return container_of(to_pool_work(ws), struct noflush_work, pw);
1782 static void do_noflush_start(struct work_struct *ws)
1784 struct noflush_work *w = to_noflush(ws);
1785 w->tc->requeue_mode = true;
1787 pool_work_complete(&w->pw);
1790 static void do_noflush_stop(struct work_struct *ws)
1792 struct noflush_work *w = to_noflush(ws);
1793 w->tc->requeue_mode = false;
1794 pool_work_complete(&w->pw);
1797 static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
1799 struct noflush_work w;
1802 pool_work_wait(&w.pw, tc->pool, fn);
1805 /*----------------------------------------------------------------*/
1807 static enum pool_mode get_pool_mode(struct pool *pool)
1809 return pool->pf.mode;
1812 static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode)
1814 dm_table_event(pool->ti->table);
1815 DMINFO("%s: switching pool to %s mode",
1816 dm_device_name(pool->pool_md), new_mode);
1819 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
1821 struct pool_c *pt = pool->ti->private;
1822 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
1823 enum pool_mode old_mode = get_pool_mode(pool);
1824 unsigned long no_space_timeout = ACCESS_ONCE(no_space_timeout_secs) * HZ;
1827 * Never allow the pool to transition to PM_WRITE mode if user
1828 * intervention is required to verify metadata and data consistency.
1830 if (new_mode == PM_WRITE && needs_check) {
1831 DMERR("%s: unable to switch pool to write mode until repaired.",
1832 dm_device_name(pool->pool_md));
1833 if (old_mode != new_mode)
1834 new_mode = old_mode;
1836 new_mode = PM_READ_ONLY;
1839 * If we were in PM_FAIL mode, rollback of metadata failed. We're
1840 * not going to recover without a thin_repair. So we never let the
1841 * pool move out of the old mode.
1843 if (old_mode == PM_FAIL)
1844 new_mode = old_mode;
1848 if (old_mode != new_mode)
1849 notify_of_pool_mode_change(pool, "failure");
1850 dm_pool_metadata_read_only(pool->pmd);
1851 pool->process_bio = process_bio_fail;
1852 pool->process_discard = process_bio_fail;
1853 pool->process_prepared_mapping = process_prepared_mapping_fail;
1854 pool->process_prepared_discard = process_prepared_discard_fail;
1856 error_retry_list(pool);
1860 if (old_mode != new_mode)
1861 notify_of_pool_mode_change(pool, "read-only");
1862 dm_pool_metadata_read_only(pool->pmd);
1863 pool->process_bio = process_bio_read_only;
1864 pool->process_discard = process_bio_success;
1865 pool->process_prepared_mapping = process_prepared_mapping_fail;
1866 pool->process_prepared_discard = process_prepared_discard_passdown;
1868 error_retry_list(pool);
1871 case PM_OUT_OF_DATA_SPACE:
1873 * Ideally we'd never hit this state; the low water mark
1874 * would trigger userland to extend the pool before we
1875 * completely run out of data space. However, many small
1876 * IOs to unprovisioned space can consume data space at an
1877 * alarming rate. Adjust your low water mark if you're
1878 * frequently seeing this mode.
1880 if (old_mode != new_mode)
1881 notify_of_pool_mode_change(pool, "out-of-data-space");
1882 pool->process_bio = process_bio_read_only;
1883 pool->process_discard = process_discard;
1884 pool->process_prepared_mapping = process_prepared_mapping;
1885 pool->process_prepared_discard = process_prepared_discard_passdown;
1887 if (!pool->pf.error_if_no_space && no_space_timeout)
1888 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
1892 if (old_mode != new_mode)
1893 notify_of_pool_mode_change(pool, "write");
1894 dm_pool_metadata_read_write(pool->pmd);
1895 pool->process_bio = process_bio;
1896 pool->process_discard = process_discard;
1897 pool->process_prepared_mapping = process_prepared_mapping;
1898 pool->process_prepared_discard = process_prepared_discard;
1902 pool->pf.mode = new_mode;
1904 * The pool mode may have changed, sync it so bind_control_target()
1905 * doesn't cause an unexpected mode transition on resume.
1907 pt->adjusted_pf.mode = new_mode;
1910 static void abort_transaction(struct pool *pool)
1912 const char *dev_name = dm_device_name(pool->pool_md);
1914 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
1915 if (dm_pool_abort_metadata(pool->pmd)) {
1916 DMERR("%s: failed to abort metadata transaction", dev_name);
1917 set_pool_mode(pool, PM_FAIL);
1920 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
1921 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
1922 set_pool_mode(pool, PM_FAIL);
1926 static void metadata_operation_failed(struct pool *pool, const char *op, int r)
1928 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
1929 dm_device_name(pool->pool_md), op, r);
1931 abort_transaction(pool);
1932 set_pool_mode(pool, PM_READ_ONLY);
1935 /*----------------------------------------------------------------*/
1938 * Mapping functions.
1942 * Called only while mapping a thin bio to hand it over to the workqueue.
1944 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1946 unsigned long flags;
1947 struct pool *pool = tc->pool;
1949 spin_lock_irqsave(&tc->lock, flags);
1950 bio_list_add(&tc->deferred_bio_list, bio);
1951 spin_unlock_irqrestore(&tc->lock, flags);
1956 static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
1958 struct pool *pool = tc->pool;
1960 throttle_lock(&pool->throttle);
1961 thin_defer_bio(tc, bio);
1962 throttle_unlock(&pool->throttle);
1965 static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
1967 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1970 h->shared_read_entry = NULL;
1971 h->all_io_entry = NULL;
1972 h->overwrite_mapping = NULL;
1976 * Non-blocking function called from the thin target's map function.
1978 static int thin_bio_map(struct dm_target *ti, struct bio *bio)
1981 struct thin_c *tc = ti->private;
1982 dm_block_t block = get_bio_block(tc, bio);
1983 struct dm_thin_device *td = tc->td;
1984 struct dm_thin_lookup_result result;
1985 struct dm_bio_prison_cell cell1, cell2;
1986 struct dm_bio_prison_cell *cell_result;
1987 struct dm_cell_key key;
1989 thin_hook_bio(tc, bio);
1991 if (tc->requeue_mode) {
1992 bio_endio(bio, DM_ENDIO_REQUEUE);
1993 return DM_MAPIO_SUBMITTED;
1996 if (get_pool_mode(tc->pool) == PM_FAIL) {
1998 return DM_MAPIO_SUBMITTED;
2001 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
2002 thin_defer_bio_with_throttle(tc, bio);
2003 return DM_MAPIO_SUBMITTED;
2007 * We must hold the virtual cell before doing the lookup, otherwise
2008 * there's a race with discard.
2010 build_virtual_key(tc->td, block, &key);
2011 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
2012 return DM_MAPIO_SUBMITTED;
2014 r = dm_thin_find_block(td, block, 0, &result);
2017 * Note that we defer readahead too.
2021 if (unlikely(result.shared)) {
2023 * We have a race condition here between the
2024 * result.shared value returned by the lookup and
2025 * snapshot creation, which may cause new
2028 * To avoid this always quiesce the origin before
2029 * taking the snap. You want to do this anyway to
2030 * ensure a consistent application view
2033 * More distant ancestors are irrelevant. The
2034 * shared flag will be set in their case.
2036 thin_defer_bio(tc, bio);
2037 cell_defer_no_holder_no_free(tc, &cell1);
2038 return DM_MAPIO_SUBMITTED;
2041 build_data_key(tc->td, result.block, &key);
2042 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
2043 cell_defer_no_holder_no_free(tc, &cell1);
2044 return DM_MAPIO_SUBMITTED;
2047 inc_all_io_entry(tc->pool, bio);
2048 cell_defer_no_holder_no_free(tc, &cell2);
2049 cell_defer_no_holder_no_free(tc, &cell1);
2051 remap(tc, bio, result.block);
2052 return DM_MAPIO_REMAPPED;
2055 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
2057 * This block isn't provisioned, and we have no way
2060 handle_unserviceable_bio(tc->pool, bio);
2061 cell_defer_no_holder_no_free(tc, &cell1);
2062 return DM_MAPIO_SUBMITTED;
2067 thin_defer_bio(tc, bio);
2068 cell_defer_no_holder_no_free(tc, &cell1);
2069 return DM_MAPIO_SUBMITTED;
2073 * Must always call bio_io_error on failure.
2074 * dm_thin_find_block can fail with -EINVAL if the
2075 * pool is switched to fail-io mode.
2078 cell_defer_no_holder_no_free(tc, &cell1);
2079 return DM_MAPIO_SUBMITTED;
2083 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
2085 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
2086 struct request_queue *q;
2088 if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE)
2091 q = bdev_get_queue(pt->data_dev->bdev);
2092 return bdi_congested(&q->backing_dev_info, bdi_bits);
2095 static void requeue_bios(struct pool *pool)
2097 unsigned long flags;
2101 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
2102 spin_lock_irqsave(&tc->lock, flags);
2103 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
2104 bio_list_init(&tc->retry_on_resume_list);
2105 spin_unlock_irqrestore(&tc->lock, flags);
2110 /*----------------------------------------------------------------
2111 * Binding of control targets to a pool object
2112 *--------------------------------------------------------------*/
2113 static bool data_dev_supports_discard(struct pool_c *pt)
2115 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2117 return q && blk_queue_discard(q);
2120 static bool is_factor(sector_t block_size, uint32_t n)
2122 return !sector_div(block_size, n);
2126 * If discard_passdown was enabled verify that the data device
2127 * supports discards. Disable discard_passdown if not.
2129 static void disable_passdown_if_not_supported(struct pool_c *pt)
2131 struct pool *pool = pt->pool;
2132 struct block_device *data_bdev = pt->data_dev->bdev;
2133 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
2134 sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
2135 const char *reason = NULL;
2136 char buf[BDEVNAME_SIZE];
2138 if (!pt->adjusted_pf.discard_passdown)
2141 if (!data_dev_supports_discard(pt))
2142 reason = "discard unsupported";
2144 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
2145 reason = "max discard sectors smaller than a block";
2147 else if (data_limits->discard_granularity > block_size)
2148 reason = "discard granularity larger than a block";
2150 else if (!is_factor(block_size, data_limits->discard_granularity))
2151 reason = "discard granularity not a factor of block size";
2154 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
2155 pt->adjusted_pf.discard_passdown = false;
2159 static int bind_control_target(struct pool *pool, struct dm_target *ti)
2161 struct pool_c *pt = ti->private;
2164 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2166 enum pool_mode old_mode = get_pool_mode(pool);
2167 enum pool_mode new_mode = pt->adjusted_pf.mode;
2170 * Don't change the pool's mode until set_pool_mode() below.
2171 * Otherwise the pool's process_* function pointers may
2172 * not match the desired pool mode.
2174 pt->adjusted_pf.mode = old_mode;
2177 pool->pf = pt->adjusted_pf;
2178 pool->low_water_blocks = pt->low_water_blocks;
2180 set_pool_mode(pool, new_mode);
2185 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2191 /*----------------------------------------------------------------
2193 *--------------------------------------------------------------*/
2194 /* Initialize pool features. */
2195 static void pool_features_init(struct pool_features *pf)
2197 pf->mode = PM_WRITE;
2198 pf->zero_new_blocks = true;
2199 pf->discard_enabled = true;
2200 pf->discard_passdown = true;
2201 pf->error_if_no_space = false;
2204 static void __pool_destroy(struct pool *pool)
2206 __pool_table_remove(pool);
2208 if (dm_pool_metadata_close(pool->pmd) < 0)
2209 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2211 dm_bio_prison_destroy(pool->prison);
2212 dm_kcopyd_client_destroy(pool->copier);
2215 destroy_workqueue(pool->wq);
2217 if (pool->next_mapping)
2218 mempool_free(pool->next_mapping, pool->mapping_pool);
2219 mempool_destroy(pool->mapping_pool);
2220 dm_deferred_set_destroy(pool->shared_read_ds);
2221 dm_deferred_set_destroy(pool->all_io_ds);
2225 static struct kmem_cache *_new_mapping_cache;
2227 static struct pool *pool_create(struct mapped_device *pool_md,
2228 struct block_device *metadata_dev,
2229 unsigned long block_size,
2230 int read_only, char **error)
2235 struct dm_pool_metadata *pmd;
2236 bool format_device = read_only ? false : true;
2238 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2240 *error = "Error creating metadata object";
2241 return (struct pool *)pmd;
2244 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
2246 *error = "Error allocating memory for pool";
2247 err_p = ERR_PTR(-ENOMEM);
2252 pool->sectors_per_block = block_size;
2253 if (block_size & (block_size - 1))
2254 pool->sectors_per_block_shift = -1;
2256 pool->sectors_per_block_shift = __ffs(block_size);
2257 pool->low_water_blocks = 0;
2258 pool_features_init(&pool->pf);
2259 pool->prison = dm_bio_prison_create();
2260 if (!pool->prison) {
2261 *error = "Error creating pool's bio prison";
2262 err_p = ERR_PTR(-ENOMEM);
2266 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2267 if (IS_ERR(pool->copier)) {
2268 r = PTR_ERR(pool->copier);
2269 *error = "Error creating pool's kcopyd client";
2271 goto bad_kcopyd_client;
2275 * Create singlethreaded workqueue that will service all devices
2276 * that use this metadata.
2278 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2280 *error = "Error creating pool's workqueue";
2281 err_p = ERR_PTR(-ENOMEM);
2285 throttle_init(&pool->throttle);
2286 INIT_WORK(&pool->worker, do_worker);
2287 INIT_DELAYED_WORK(&pool->waker, do_waker);
2288 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
2289 spin_lock_init(&pool->lock);
2290 bio_list_init(&pool->deferred_flush_bios);
2291 INIT_LIST_HEAD(&pool->prepared_mappings);
2292 INIT_LIST_HEAD(&pool->prepared_discards);
2293 INIT_LIST_HEAD(&pool->active_thins);
2294 pool->low_water_triggered = false;
2296 pool->shared_read_ds = dm_deferred_set_create();
2297 if (!pool->shared_read_ds) {
2298 *error = "Error creating pool's shared read deferred set";
2299 err_p = ERR_PTR(-ENOMEM);
2300 goto bad_shared_read_ds;
2303 pool->all_io_ds = dm_deferred_set_create();
2304 if (!pool->all_io_ds) {
2305 *error = "Error creating pool's all io deferred set";
2306 err_p = ERR_PTR(-ENOMEM);
2310 pool->next_mapping = NULL;
2311 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
2312 _new_mapping_cache);
2313 if (!pool->mapping_pool) {
2314 *error = "Error creating pool's mapping mempool";
2315 err_p = ERR_PTR(-ENOMEM);
2316 goto bad_mapping_pool;
2319 pool->ref_count = 1;
2320 pool->last_commit_jiffies = jiffies;
2321 pool->pool_md = pool_md;
2322 pool->md_dev = metadata_dev;
2323 __pool_table_insert(pool);
2328 dm_deferred_set_destroy(pool->all_io_ds);
2330 dm_deferred_set_destroy(pool->shared_read_ds);
2332 destroy_workqueue(pool->wq);
2334 dm_kcopyd_client_destroy(pool->copier);
2336 dm_bio_prison_destroy(pool->prison);
2340 if (dm_pool_metadata_close(pmd))
2341 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2346 static void __pool_inc(struct pool *pool)
2348 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2352 static void __pool_dec(struct pool *pool)
2354 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2355 BUG_ON(!pool->ref_count);
2356 if (!--pool->ref_count)
2357 __pool_destroy(pool);
2360 static struct pool *__pool_find(struct mapped_device *pool_md,
2361 struct block_device *metadata_dev,
2362 unsigned long block_size, int read_only,
2363 char **error, int *created)
2365 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
2368 if (pool->pool_md != pool_md) {
2369 *error = "metadata device already in use by a pool";
2370 return ERR_PTR(-EBUSY);
2375 pool = __pool_table_lookup(pool_md);
2377 if (pool->md_dev != metadata_dev) {
2378 *error = "different pool cannot replace a pool";
2379 return ERR_PTR(-EINVAL);
2384 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
2392 /*----------------------------------------------------------------
2393 * Pool target methods
2394 *--------------------------------------------------------------*/
2395 static void pool_dtr(struct dm_target *ti)
2397 struct pool_c *pt = ti->private;
2399 mutex_lock(&dm_thin_pool_table.mutex);
2401 unbind_control_target(pt->pool, ti);
2402 __pool_dec(pt->pool);
2403 dm_put_device(ti, pt->metadata_dev);
2404 dm_put_device(ti, pt->data_dev);
2407 mutex_unlock(&dm_thin_pool_table.mutex);
2410 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
2411 struct dm_target *ti)
2415 const char *arg_name;
2417 static struct dm_arg _args[] = {
2418 {0, 4, "Invalid number of pool feature arguments"},
2422 * No feature arguments supplied.
2427 r = dm_read_arg_group(_args, as, &argc, &ti->error);
2431 while (argc && !r) {
2432 arg_name = dm_shift_arg(as);
2435 if (!strcasecmp(arg_name, "skip_block_zeroing"))
2436 pf->zero_new_blocks = false;
2438 else if (!strcasecmp(arg_name, "ignore_discard"))
2439 pf->discard_enabled = false;
2441 else if (!strcasecmp(arg_name, "no_discard_passdown"))
2442 pf->discard_passdown = false;
2444 else if (!strcasecmp(arg_name, "read_only"))
2445 pf->mode = PM_READ_ONLY;
2447 else if (!strcasecmp(arg_name, "error_if_no_space"))
2448 pf->error_if_no_space = true;
2451 ti->error = "Unrecognised pool feature requested";
2460 static void metadata_low_callback(void *context)
2462 struct pool *pool = context;
2464 DMWARN("%s: reached low water mark for metadata device: sending event.",
2465 dm_device_name(pool->pool_md));
2467 dm_table_event(pool->ti->table);
2470 static sector_t get_dev_size(struct block_device *bdev)
2472 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
2475 static void warn_if_metadata_device_too_big(struct block_device *bdev)
2477 sector_t metadata_dev_size = get_dev_size(bdev);
2478 char buffer[BDEVNAME_SIZE];
2480 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
2481 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
2482 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
2485 static sector_t get_metadata_dev_size(struct block_device *bdev)
2487 sector_t metadata_dev_size = get_dev_size(bdev);
2489 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
2490 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
2492 return metadata_dev_size;
2495 static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
2497 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
2499 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
2501 return metadata_dev_size;
2505 * When a metadata threshold is crossed a dm event is triggered, and
2506 * userland should respond by growing the metadata device. We could let
2507 * userland set the threshold, like we do with the data threshold, but I'm
2508 * not sure they know enough to do this well.
2510 static dm_block_t calc_metadata_threshold(struct pool_c *pt)
2513 * 4M is ample for all ops with the possible exception of thin
2514 * device deletion which is harmless if it fails (just retry the
2515 * delete after you've grown the device).
2517 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
2518 return min((dm_block_t)1024ULL /* 4M */, quarter);
2522 * thin-pool <metadata dev> <data dev>
2523 * <data block size (sectors)>
2524 * <low water mark (blocks)>
2525 * [<#feature args> [<arg>]*]
2527 * Optional feature arguments are:
2528 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
2529 * ignore_discard: disable discard
2530 * no_discard_passdown: don't pass discards down to the data device
2531 * read_only: Don't allow any changes to be made to the pool metadata.
2532 * error_if_no_space: error IOs, instead of queueing, if no space.
2534 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
2536 int r, pool_created = 0;
2539 struct pool_features pf;
2540 struct dm_arg_set as;
2541 struct dm_dev *data_dev;
2542 unsigned long block_size;
2543 dm_block_t low_water_blocks;
2544 struct dm_dev *metadata_dev;
2545 fmode_t metadata_mode;
2548 * FIXME Remove validation from scope of lock.
2550 mutex_lock(&dm_thin_pool_table.mutex);
2553 ti->error = "Invalid argument count";
2562 * Set default pool features.
2564 pool_features_init(&pf);
2566 dm_consume_args(&as, 4);
2567 r = parse_pool_features(&as, &pf, ti);
2571 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
2572 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
2574 ti->error = "Error opening metadata block device";
2577 warn_if_metadata_device_too_big(metadata_dev->bdev);
2579 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
2581 ti->error = "Error getting data device";
2585 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
2586 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
2587 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
2588 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
2589 ti->error = "Invalid block size";
2594 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
2595 ti->error = "Invalid low water mark";
2600 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
2606 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
2607 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
2614 * 'pool_created' reflects whether this is the first table load.
2615 * Top level discard support is not allowed to be changed after
2616 * initial load. This would require a pool reload to trigger thin
2619 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
2620 ti->error = "Discard support cannot be disabled once enabled";
2622 goto out_flags_changed;
2627 pt->metadata_dev = metadata_dev;
2628 pt->data_dev = data_dev;
2629 pt->low_water_blocks = low_water_blocks;
2630 pt->adjusted_pf = pt->requested_pf = pf;
2631 ti->num_flush_bios = 1;
2634 * Only need to enable discards if the pool should pass
2635 * them down to the data device. The thin device's discard
2636 * processing will cause mappings to be removed from the btree.
2638 ti->discard_zeroes_data_unsupported = true;
2639 if (pf.discard_enabled && pf.discard_passdown) {
2640 ti->num_discard_bios = 1;
2643 * Setting 'discards_supported' circumvents the normal
2644 * stacking of discard limits (this keeps the pool and
2645 * thin devices' discard limits consistent).
2647 ti->discards_supported = true;
2651 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
2652 calc_metadata_threshold(pt),
2653 metadata_low_callback,
2658 pt->callbacks.congested_fn = pool_is_congested;
2659 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2661 mutex_unlock(&dm_thin_pool_table.mutex);
2670 dm_put_device(ti, data_dev);
2672 dm_put_device(ti, metadata_dev);
2674 mutex_unlock(&dm_thin_pool_table.mutex);
2679 static int pool_map(struct dm_target *ti, struct bio *bio)
2682 struct pool_c *pt = ti->private;
2683 struct pool *pool = pt->pool;
2684 unsigned long flags;
2687 * As this is a singleton target, ti->begin is always zero.
2689 spin_lock_irqsave(&pool->lock, flags);
2690 bio->bi_bdev = pt->data_dev->bdev;
2691 r = DM_MAPIO_REMAPPED;
2692 spin_unlock_irqrestore(&pool->lock, flags);
2697 static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
2700 struct pool_c *pt = ti->private;
2701 struct pool *pool = pt->pool;
2702 sector_t data_size = ti->len;
2703 dm_block_t sb_data_size;
2705 *need_commit = false;
2707 (void) sector_div(data_size, pool->sectors_per_block);
2709 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2711 DMERR("%s: failed to retrieve data device size",
2712 dm_device_name(pool->pool_md));
2716 if (data_size < sb_data_size) {
2717 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
2718 dm_device_name(pool->pool_md),
2719 (unsigned long long)data_size, sb_data_size);
2722 } else if (data_size > sb_data_size) {
2723 if (dm_pool_metadata_needs_check(pool->pmd)) {
2724 DMERR("%s: unable to grow the data device until repaired.",
2725 dm_device_name(pool->pool_md));
2730 DMINFO("%s: growing the data device from %llu to %llu blocks",
2731 dm_device_name(pool->pool_md),
2732 sb_data_size, (unsigned long long)data_size);
2733 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2735 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
2739 *need_commit = true;
2745 static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
2748 struct pool_c *pt = ti->private;
2749 struct pool *pool = pt->pool;
2750 dm_block_t metadata_dev_size, sb_metadata_dev_size;
2752 *need_commit = false;
2754 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
2756 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
2758 DMERR("%s: failed to retrieve metadata device size",
2759 dm_device_name(pool->pool_md));
2763 if (metadata_dev_size < sb_metadata_dev_size) {
2764 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
2765 dm_device_name(pool->pool_md),
2766 metadata_dev_size, sb_metadata_dev_size);
2769 } else if (metadata_dev_size > sb_metadata_dev_size) {
2770 if (dm_pool_metadata_needs_check(pool->pmd)) {
2771 DMERR("%s: unable to grow the metadata device until repaired.",
2772 dm_device_name(pool->pool_md));
2776 warn_if_metadata_device_too_big(pool->md_dev);
2777 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
2778 dm_device_name(pool->pool_md),
2779 sb_metadata_dev_size, metadata_dev_size);
2780 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
2782 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
2786 *need_commit = true;
2793 * Retrieves the number of blocks of the data device from
2794 * the superblock and compares it to the actual device size,
2795 * thus resizing the data device in case it has grown.
2797 * This both copes with opening preallocated data devices in the ctr
2798 * being followed by a resume
2800 * calling the resume method individually after userspace has
2801 * grown the data device in reaction to a table event.
2803 static int pool_preresume(struct dm_target *ti)
2806 bool need_commit1, need_commit2;
2807 struct pool_c *pt = ti->private;
2808 struct pool *pool = pt->pool;
2811 * Take control of the pool object.
2813 r = bind_control_target(pool, ti);
2817 r = maybe_resize_data_dev(ti, &need_commit1);
2821 r = maybe_resize_metadata_dev(ti, &need_commit2);
2825 if (need_commit1 || need_commit2)
2826 (void) commit(pool);
2831 static void pool_resume(struct dm_target *ti)
2833 struct pool_c *pt = ti->private;
2834 struct pool *pool = pt->pool;
2835 unsigned long flags;
2837 spin_lock_irqsave(&pool->lock, flags);
2838 pool->low_water_triggered = false;
2839 spin_unlock_irqrestore(&pool->lock, flags);
2842 do_waker(&pool->waker.work);
2845 static void pool_postsuspend(struct dm_target *ti)
2847 struct pool_c *pt = ti->private;
2848 struct pool *pool = pt->pool;
2850 cancel_delayed_work(&pool->waker);
2851 cancel_delayed_work(&pool->no_space_timeout);
2852 flush_workqueue(pool->wq);
2853 (void) commit(pool);
2856 static int check_arg_count(unsigned argc, unsigned args_required)
2858 if (argc != args_required) {
2859 DMWARN("Message received with %u arguments instead of %u.",
2860 argc, args_required);
2867 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2869 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2870 *dev_id <= MAX_DEV_ID)
2874 DMWARN("Message received with invalid device id: %s", arg);
2879 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2884 r = check_arg_count(argc, 2);
2888 r = read_dev_id(argv[1], &dev_id, 1);
2892 r = dm_pool_create_thin(pool->pmd, dev_id);
2894 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2902 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2905 dm_thin_id origin_dev_id;
2908 r = check_arg_count(argc, 3);
2912 r = read_dev_id(argv[1], &dev_id, 1);
2916 r = read_dev_id(argv[2], &origin_dev_id, 1);
2920 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2922 DMWARN("Creation of new snapshot %s of device %s failed.",
2930 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2935 r = check_arg_count(argc, 2);
2939 r = read_dev_id(argv[1], &dev_id, 1);
2943 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2945 DMWARN("Deletion of thin device %s failed.", argv[1]);
2950 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2952 dm_thin_id old_id, new_id;
2955 r = check_arg_count(argc, 3);
2959 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2960 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2964 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2965 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2969 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2971 DMWARN("Failed to change transaction id from %s to %s.",
2979 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2983 r = check_arg_count(argc, 1);
2987 (void) commit(pool);
2989 r = dm_pool_reserve_metadata_snap(pool->pmd);
2991 DMWARN("reserve_metadata_snap message failed.");
2996 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3000 r = check_arg_count(argc, 1);
3004 r = dm_pool_release_metadata_snap(pool->pmd);
3006 DMWARN("release_metadata_snap message failed.");
3012 * Messages supported:
3013 * create_thin <dev_id>
3014 * create_snap <dev_id> <origin_id>
3016 * trim <dev_id> <new_size_in_sectors>
3017 * set_transaction_id <current_trans_id> <new_trans_id>
3018 * reserve_metadata_snap
3019 * release_metadata_snap
3021 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
3024 struct pool_c *pt = ti->private;
3025 struct pool *pool = pt->pool;
3027 if (!strcasecmp(argv[0], "create_thin"))
3028 r = process_create_thin_mesg(argc, argv, pool);
3030 else if (!strcasecmp(argv[0], "create_snap"))
3031 r = process_create_snap_mesg(argc, argv, pool);
3033 else if (!strcasecmp(argv[0], "delete"))
3034 r = process_delete_mesg(argc, argv, pool);
3036 else if (!strcasecmp(argv[0], "set_transaction_id"))
3037 r = process_set_transaction_id_mesg(argc, argv, pool);
3039 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
3040 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
3042 else if (!strcasecmp(argv[0], "release_metadata_snap"))
3043 r = process_release_metadata_snap_mesg(argc, argv, pool);
3046 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
3049 (void) commit(pool);
3054 static void emit_flags(struct pool_features *pf, char *result,
3055 unsigned sz, unsigned maxlen)
3057 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
3058 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
3059 pf->error_if_no_space;
3060 DMEMIT("%u ", count);
3062 if (!pf->zero_new_blocks)
3063 DMEMIT("skip_block_zeroing ");
3065 if (!pf->discard_enabled)
3066 DMEMIT("ignore_discard ");
3068 if (!pf->discard_passdown)
3069 DMEMIT("no_discard_passdown ");
3071 if (pf->mode == PM_READ_ONLY)
3072 DMEMIT("read_only ");
3074 if (pf->error_if_no_space)
3075 DMEMIT("error_if_no_space ");
3080 * <transaction id> <used metadata sectors>/<total metadata sectors>
3081 * <used data sectors>/<total data sectors> <held metadata root>
3083 static void pool_status(struct dm_target *ti, status_type_t type,
3084 unsigned status_flags, char *result, unsigned maxlen)
3088 uint64_t transaction_id;
3089 dm_block_t nr_free_blocks_data;
3090 dm_block_t nr_free_blocks_metadata;
3091 dm_block_t nr_blocks_data;
3092 dm_block_t nr_blocks_metadata;
3093 dm_block_t held_root;
3094 char buf[BDEVNAME_SIZE];
3095 char buf2[BDEVNAME_SIZE];
3096 struct pool_c *pt = ti->private;
3097 struct pool *pool = pt->pool;
3100 case STATUSTYPE_INFO:
3101 if (get_pool_mode(pool) == PM_FAIL) {
3106 /* Commit to ensure statistics aren't out-of-date */
3107 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3108 (void) commit(pool);
3110 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
3112 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
3113 dm_device_name(pool->pool_md), r);
3117 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
3119 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
3120 dm_device_name(pool->pool_md), r);
3124 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
3126 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
3127 dm_device_name(pool->pool_md), r);
3131 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
3133 DMERR("%s: dm_pool_get_free_block_count returned %d",
3134 dm_device_name(pool->pool_md), r);
3138 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
3140 DMERR("%s: dm_pool_get_data_dev_size returned %d",
3141 dm_device_name(pool->pool_md), r);
3145 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
3147 DMERR("%s: dm_pool_get_metadata_snap returned %d",
3148 dm_device_name(pool->pool_md), r);
3152 DMEMIT("%llu %llu/%llu %llu/%llu ",
3153 (unsigned long long)transaction_id,
3154 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3155 (unsigned long long)nr_blocks_metadata,
3156 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
3157 (unsigned long long)nr_blocks_data);
3160 DMEMIT("%llu ", held_root);
3164 if (pool->pf.mode == PM_OUT_OF_DATA_SPACE)
3165 DMEMIT("out_of_data_space ");
3166 else if (pool->pf.mode == PM_READ_ONLY)
3171 if (!pool->pf.discard_enabled)
3172 DMEMIT("ignore_discard ");
3173 else if (pool->pf.discard_passdown)
3174 DMEMIT("discard_passdown ");
3176 DMEMIT("no_discard_passdown ");
3178 if (pool->pf.error_if_no_space)
3179 DMEMIT("error_if_no_space ");
3181 DMEMIT("queue_if_no_space ");
3185 case STATUSTYPE_TABLE:
3186 DMEMIT("%s %s %lu %llu ",
3187 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
3188 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
3189 (unsigned long)pool->sectors_per_block,
3190 (unsigned long long)pt->low_water_blocks);
3191 emit_flags(&pt->requested_pf, result, sz, maxlen);
3200 static int pool_iterate_devices(struct dm_target *ti,
3201 iterate_devices_callout_fn fn, void *data)
3203 struct pool_c *pt = ti->private;
3205 return fn(ti, pt->data_dev, 0, ti->len, data);
3208 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
3209 struct bio_vec *biovec, int max_size)
3211 struct pool_c *pt = ti->private;
3212 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
3214 if (!q->merge_bvec_fn)
3217 bvm->bi_bdev = pt->data_dev->bdev;
3219 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3222 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
3224 struct pool *pool = pt->pool;
3225 struct queue_limits *data_limits;
3227 limits->max_discard_sectors = pool->sectors_per_block;
3230 * discard_granularity is just a hint, and not enforced.
3232 if (pt->adjusted_pf.discard_passdown) {
3233 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
3234 limits->discard_granularity = max(data_limits->discard_granularity,
3235 pool->sectors_per_block << SECTOR_SHIFT);
3237 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
3240 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
3242 struct pool_c *pt = ti->private;
3243 struct pool *pool = pt->pool;
3244 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
3247 * Adjust max_sectors_kb to highest possible power-of-2
3248 * factor of pool->sectors_per_block.
3250 if (limits->max_hw_sectors & (limits->max_hw_sectors - 1))
3251 limits->max_sectors = rounddown_pow_of_two(limits->max_hw_sectors);
3253 limits->max_sectors = limits->max_hw_sectors;
3255 if (limits->max_sectors < pool->sectors_per_block) {
3256 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
3257 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
3258 limits->max_sectors--;
3259 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
3261 } else if (block_size_is_power_of_two(pool)) {
3262 /* max_sectors_kb is >= power-of-2 thinp blocksize */
3263 while (!is_factor(limits->max_sectors, pool->sectors_per_block)) {
3264 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
3265 limits->max_sectors--;
3266 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
3271 * If the system-determined stacked limits are compatible with the
3272 * pool's blocksize (io_opt is a factor) do not override them.
3274 if (io_opt_sectors < pool->sectors_per_block ||
3275 !is_factor(io_opt_sectors, pool->sectors_per_block)) {
3276 if (is_factor(pool->sectors_per_block, limits->max_sectors))
3277 blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT);
3279 blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);
3280 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
3284 * pt->adjusted_pf is a staging area for the actual features to use.
3285 * They get transferred to the live pool in bind_control_target()
3286 * called from pool_preresume().
3288 if (!pt->adjusted_pf.discard_enabled) {
3290 * Must explicitly disallow stacking discard limits otherwise the
3291 * block layer will stack them if pool's data device has support.
3292 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
3293 * user to see that, so make sure to set all discard limits to 0.
3295 limits->discard_granularity = 0;
3299 disable_passdown_if_not_supported(pt);
3301 set_discard_limits(pt, limits);
3304 static struct target_type pool_target = {
3305 .name = "thin-pool",
3306 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
3307 DM_TARGET_IMMUTABLE,
3308 .version = {1, 14, 0},
3309 .module = THIS_MODULE,
3313 .postsuspend = pool_postsuspend,
3314 .preresume = pool_preresume,
3315 .resume = pool_resume,
3316 .message = pool_message,
3317 .status = pool_status,
3318 .merge = pool_merge,
3319 .iterate_devices = pool_iterate_devices,
3320 .io_hints = pool_io_hints,
3323 /*----------------------------------------------------------------
3324 * Thin target methods
3325 *--------------------------------------------------------------*/
3326 static void thin_get(struct thin_c *tc)
3328 atomic_inc(&tc->refcount);
3331 static void thin_put(struct thin_c *tc)
3333 if (atomic_dec_and_test(&tc->refcount))
3334 complete(&tc->can_destroy);
3337 static void thin_dtr(struct dm_target *ti)
3339 struct thin_c *tc = ti->private;
3340 unsigned long flags;
3343 wait_for_completion(&tc->can_destroy);
3345 spin_lock_irqsave(&tc->pool->lock, flags);
3346 list_del_rcu(&tc->list);
3347 spin_unlock_irqrestore(&tc->pool->lock, flags);
3350 mutex_lock(&dm_thin_pool_table.mutex);
3352 __pool_dec(tc->pool);
3353 dm_pool_close_thin_device(tc->td);
3354 dm_put_device(ti, tc->pool_dev);
3356 dm_put_device(ti, tc->origin_dev);
3359 mutex_unlock(&dm_thin_pool_table.mutex);
3363 * Thin target parameters:
3365 * <pool_dev> <dev_id> [origin_dev]
3367 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
3368 * dev_id: the internal device identifier
3369 * origin_dev: a device external to the pool that should act as the origin
3371 * If the pool device has discards disabled, they get disabled for the thin
3374 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
3378 struct dm_dev *pool_dev, *origin_dev;
3379 struct mapped_device *pool_md;
3380 unsigned long flags;
3382 mutex_lock(&dm_thin_pool_table.mutex);
3384 if (argc != 2 && argc != 3) {
3385 ti->error = "Invalid argument count";
3390 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
3392 ti->error = "Out of memory";
3396 spin_lock_init(&tc->lock);
3397 bio_list_init(&tc->deferred_bio_list);
3398 bio_list_init(&tc->retry_on_resume_list);
3399 tc->sort_bio_list = RB_ROOT;
3402 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
3404 ti->error = "Error opening origin device";
3405 goto bad_origin_dev;
3407 tc->origin_dev = origin_dev;
3410 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
3412 ti->error = "Error opening pool device";
3415 tc->pool_dev = pool_dev;
3417 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
3418 ti->error = "Invalid device id";
3423 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
3425 ti->error = "Couldn't get pool mapped device";
3430 tc->pool = __pool_table_lookup(pool_md);
3432 ti->error = "Couldn't find pool object";
3434 goto bad_pool_lookup;
3436 __pool_inc(tc->pool);
3438 if (get_pool_mode(tc->pool) == PM_FAIL) {
3439 ti->error = "Couldn't open thin device, Pool is in fail mode";
3444 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
3446 ti->error = "Couldn't open thin internal device";
3450 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
3452 goto bad_target_max_io_len;
3454 ti->num_flush_bios = 1;
3455 ti->flush_supported = true;
3456 ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
3458 /* In case the pool supports discards, pass them on. */
3459 ti->discard_zeroes_data_unsupported = true;
3460 if (tc->pool->pf.discard_enabled) {
3461 ti->discards_supported = true;
3462 ti->num_discard_bios = 1;
3463 /* Discard bios must be split on a block boundary */
3464 ti->split_discard_bios = true;
3469 mutex_unlock(&dm_thin_pool_table.mutex);
3471 atomic_set(&tc->refcount, 1);
3472 init_completion(&tc->can_destroy);
3474 spin_lock_irqsave(&tc->pool->lock, flags);
3475 list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
3476 spin_unlock_irqrestore(&tc->pool->lock, flags);
3478 * This synchronize_rcu() call is needed here otherwise we risk a
3479 * wake_worker() call finding no bios to process (because the newly
3480 * added tc isn't yet visible). So this reduces latency since we
3481 * aren't then dependent on the periodic commit to wake_worker().
3487 bad_target_max_io_len:
3488 dm_pool_close_thin_device(tc->td);
3490 __pool_dec(tc->pool);
3494 dm_put_device(ti, tc->pool_dev);
3497 dm_put_device(ti, tc->origin_dev);
3501 mutex_unlock(&dm_thin_pool_table.mutex);
3506 static int thin_map(struct dm_target *ti, struct bio *bio)
3508 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
3510 return thin_bio_map(ti, bio);
3513 static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
3515 unsigned long flags;
3516 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
3517 struct list_head work;
3518 struct dm_thin_new_mapping *m, *tmp;
3519 struct pool *pool = h->tc->pool;
3521 if (h->shared_read_entry) {
3522 INIT_LIST_HEAD(&work);
3523 dm_deferred_entry_dec(h->shared_read_entry, &work);
3525 spin_lock_irqsave(&pool->lock, flags);
3526 list_for_each_entry_safe(m, tmp, &work, list) {
3528 __complete_mapping_preparation(m);
3530 spin_unlock_irqrestore(&pool->lock, flags);
3533 if (h->all_io_entry) {
3534 INIT_LIST_HEAD(&work);
3535 dm_deferred_entry_dec(h->all_io_entry, &work);
3536 if (!list_empty(&work)) {
3537 spin_lock_irqsave(&pool->lock, flags);
3538 list_for_each_entry_safe(m, tmp, &work, list)
3539 list_add_tail(&m->list, &pool->prepared_discards);
3540 spin_unlock_irqrestore(&pool->lock, flags);
3548 static void thin_presuspend(struct dm_target *ti)
3550 struct thin_c *tc = ti->private;
3552 if (dm_noflush_suspending(ti))
3553 noflush_work(tc, do_noflush_start);
3556 static void thin_postsuspend(struct dm_target *ti)
3558 struct thin_c *tc = ti->private;
3561 * The dm_noflush_suspending flag has been cleared by now, so
3562 * unfortunately we must always run this.
3564 noflush_work(tc, do_noflush_stop);
3567 static int thin_preresume(struct dm_target *ti)
3569 struct thin_c *tc = ti->private;
3572 tc->origin_size = get_dev_size(tc->origin_dev->bdev);
3578 * <nr mapped sectors> <highest mapped sector>
3580 static void thin_status(struct dm_target *ti, status_type_t type,
3581 unsigned status_flags, char *result, unsigned maxlen)
3585 dm_block_t mapped, highest;
3586 char buf[BDEVNAME_SIZE];
3587 struct thin_c *tc = ti->private;
3589 if (get_pool_mode(tc->pool) == PM_FAIL) {
3598 case STATUSTYPE_INFO:
3599 r = dm_thin_get_mapped_count(tc->td, &mapped);
3601 DMERR("dm_thin_get_mapped_count returned %d", r);
3605 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
3607 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
3611 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
3613 DMEMIT("%llu", ((highest + 1) *
3614 tc->pool->sectors_per_block) - 1);
3619 case STATUSTYPE_TABLE:
3621 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
3622 (unsigned long) tc->dev_id);
3624 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
3635 static int thin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
3636 struct bio_vec *biovec, int max_size)
3638 struct thin_c *tc = ti->private;
3639 struct request_queue *q = bdev_get_queue(tc->pool_dev->bdev);
3641 if (!q->merge_bvec_fn)
3644 bvm->bi_bdev = tc->pool_dev->bdev;
3645 bvm->bi_sector = dm_target_offset(ti, bvm->bi_sector);
3647 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3650 static int thin_iterate_devices(struct dm_target *ti,
3651 iterate_devices_callout_fn fn, void *data)
3654 struct thin_c *tc = ti->private;
3655 struct pool *pool = tc->pool;
3658 * We can't call dm_pool_get_data_dev_size() since that blocks. So
3659 * we follow a more convoluted path through to the pool's target.
3662 return 0; /* nothing is bound */
3664 blocks = pool->ti->len;
3665 (void) sector_div(blocks, pool->sectors_per_block);
3667 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
3672 static struct target_type thin_target = {
3674 .version = {1, 14, 0},
3675 .module = THIS_MODULE,
3679 .end_io = thin_endio,
3680 .preresume = thin_preresume,
3681 .presuspend = thin_presuspend,
3682 .postsuspend = thin_postsuspend,
3683 .status = thin_status,
3684 .merge = thin_merge,
3685 .iterate_devices = thin_iterate_devices,
3688 /*----------------------------------------------------------------*/
3690 static int __init dm_thin_init(void)
3696 r = dm_register_target(&thin_target);
3700 r = dm_register_target(&pool_target);
3702 goto bad_pool_target;
3706 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
3707 if (!_new_mapping_cache)
3708 goto bad_new_mapping_cache;
3712 bad_new_mapping_cache:
3713 dm_unregister_target(&pool_target);
3715 dm_unregister_target(&thin_target);
3720 static void dm_thin_exit(void)
3722 dm_unregister_target(&thin_target);
3723 dm_unregister_target(&pool_target);
3725 kmem_cache_destroy(_new_mapping_cache);
3728 module_init(dm_thin_init);
3729 module_exit(dm_thin_exit);
3731 module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);
3732 MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
3734 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
3735 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3736 MODULE_LICENSE("GPL");