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/sort.h>
21 #include <linux/rbtree.h>
23 #define DM_MSG_PREFIX "thin"
28 #define ENDIO_HOOK_POOL_SIZE 1024
29 #define MAPPING_POOL_SIZE 1024
30 #define COMMIT_PERIOD HZ
31 #define NO_SPACE_TIMEOUT_SECS 60
33 static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
35 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
36 "A percentage of time allocated for copy on write");
39 * The block size of the device holding pool data must be
40 * between 64KB and 1GB.
42 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
43 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
46 * Device id is restricted to 24 bits.
48 #define MAX_DEV_ID ((1 << 24) - 1)
51 * How do we handle breaking sharing of data blocks?
52 * =================================================
54 * We use a standard copy-on-write btree to store the mappings for the
55 * devices (note I'm talking about copy-on-write of the metadata here, not
56 * the data). When you take an internal snapshot you clone the root node
57 * of the origin btree. After this there is no concept of an origin or a
58 * snapshot. They are just two device trees that happen to point to the
61 * When we get a write in we decide if it's to a shared data block using
62 * some timestamp magic. If it is, we have to break sharing.
64 * Let's say we write to a shared block in what was the origin. The
67 * i) plug io further to this physical block. (see bio_prison code).
69 * ii) quiesce any read io to that shared data block. Obviously
70 * including all devices that share this block. (see dm_deferred_set code)
72 * iii) copy the data block to a newly allocate block. This step can be
73 * missed out if the io covers the block. (schedule_copy).
75 * iv) insert the new mapping into the origin's btree
76 * (process_prepared_mapping). This act of inserting breaks some
77 * sharing of btree nodes between the two devices. Breaking sharing only
78 * effects the btree of that specific device. Btrees for the other
79 * devices that share the block never change. The btree for the origin
80 * device as it was after the last commit is untouched, ie. we're using
81 * persistent data structures in the functional programming sense.
83 * v) unplug io to this physical block, including the io that triggered
84 * the breaking of sharing.
86 * Steps (ii) and (iii) occur in parallel.
88 * The metadata _doesn't_ need to be committed before the io continues. We
89 * get away with this because the io is always written to a _new_ block.
90 * If there's a crash, then:
92 * - The origin mapping will point to the old origin block (the shared
93 * one). This will contain the data as it was before the io that triggered
94 * the breaking of sharing came in.
96 * - The snap mapping still points to the old block. As it would after
99 * The downside of this scheme is the timestamp magic isn't perfect, and
100 * will continue to think that data block in the snapshot device is shared
101 * even after the write to the origin has broken sharing. I suspect data
102 * blocks will typically be shared by many different devices, so we're
103 * breaking sharing n + 1 times, rather than n, where n is the number of
104 * devices that reference this data block. At the moment I think the
105 * benefits far, far outweigh the disadvantages.
108 /*----------------------------------------------------------------*/
113 static void build_data_key(struct dm_thin_device *td,
114 dm_block_t b, struct dm_cell_key *key)
117 key->dev = dm_thin_dev_id(td);
118 key->block_begin = b;
119 key->block_end = b + 1ULL;
122 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
123 struct dm_cell_key *key)
126 key->dev = dm_thin_dev_id(td);
127 key->block_begin = b;
128 key->block_end = b + 1ULL;
131 /*----------------------------------------------------------------*/
133 #define THROTTLE_THRESHOLD (1 * HZ)
136 struct rw_semaphore lock;
137 unsigned long threshold;
138 bool throttle_applied;
141 static void throttle_init(struct throttle *t)
143 init_rwsem(&t->lock);
144 t->throttle_applied = false;
147 static void throttle_work_start(struct throttle *t)
149 t->threshold = jiffies + THROTTLE_THRESHOLD;
152 static void throttle_work_update(struct throttle *t)
154 if (!t->throttle_applied && jiffies > t->threshold) {
155 down_write(&t->lock);
156 t->throttle_applied = true;
160 static void throttle_work_complete(struct throttle *t)
162 if (t->throttle_applied) {
163 t->throttle_applied = false;
168 static void throttle_lock(struct throttle *t)
173 static void throttle_unlock(struct throttle *t)
178 /*----------------------------------------------------------------*/
181 * A pool device ties together a metadata device and a data device. It
182 * also provides the interface for creating and destroying internal
185 struct dm_thin_new_mapping;
188 * The pool runs in 4 modes. Ordered in degraded order for comparisons.
191 PM_WRITE, /* metadata may be changed */
192 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
193 PM_READ_ONLY, /* metadata may not be changed */
194 PM_FAIL, /* all I/O fails */
197 struct pool_features {
200 bool zero_new_blocks:1;
201 bool discard_enabled:1;
202 bool discard_passdown:1;
203 bool error_if_no_space:1;
207 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
208 typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell);
209 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
211 #define CELL_SORT_ARRAY_SIZE 8192
214 struct list_head list;
215 struct dm_target *ti; /* Only set if a pool target is bound */
217 struct mapped_device *pool_md;
218 struct block_device *md_dev;
219 struct dm_pool_metadata *pmd;
221 dm_block_t low_water_blocks;
222 uint32_t sectors_per_block;
223 int sectors_per_block_shift;
225 struct pool_features pf;
226 bool low_water_triggered:1; /* A dm event has been sent */
229 struct dm_bio_prison *prison;
230 struct dm_kcopyd_client *copier;
232 struct workqueue_struct *wq;
233 struct throttle throttle;
234 struct work_struct worker;
235 struct delayed_work waker;
236 struct delayed_work no_space_timeout;
238 unsigned long last_commit_jiffies;
242 struct bio_list deferred_flush_bios;
243 struct list_head prepared_mappings;
244 struct list_head prepared_discards;
245 struct list_head active_thins;
247 struct dm_deferred_set *shared_read_ds;
248 struct dm_deferred_set *all_io_ds;
250 struct dm_thin_new_mapping *next_mapping;
251 mempool_t *mapping_pool;
253 process_bio_fn process_bio;
254 process_bio_fn process_discard;
256 process_cell_fn process_cell;
257 process_cell_fn process_discard_cell;
259 process_mapping_fn process_prepared_mapping;
260 process_mapping_fn process_prepared_discard;
262 struct dm_bio_prison_cell *cell_sort_array[CELL_SORT_ARRAY_SIZE];
265 static enum pool_mode get_pool_mode(struct pool *pool);
266 static void metadata_operation_failed(struct pool *pool, const char *op, int r);
269 * Target context for a pool.
272 struct dm_target *ti;
274 struct dm_dev *data_dev;
275 struct dm_dev *metadata_dev;
276 struct dm_target_callbacks callbacks;
278 dm_block_t low_water_blocks;
279 struct pool_features requested_pf; /* Features requested during table load */
280 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
284 * Target context for a thin.
287 struct list_head list;
288 struct dm_dev *pool_dev;
289 struct dm_dev *origin_dev;
290 sector_t origin_size;
294 struct dm_thin_device *td;
297 struct list_head deferred_cells;
298 struct bio_list deferred_bio_list;
299 struct bio_list retry_on_resume_list;
300 struct rb_root sort_bio_list; /* sorted list of deferred bios */
303 * Ensures the thin is not destroyed until the worker has finished
304 * iterating the active_thins list.
307 struct completion can_destroy;
310 /*----------------------------------------------------------------*/
313 * wake_worker() is used when new work is queued and when pool_resume is
314 * ready to continue deferred IO processing.
316 static void wake_worker(struct pool *pool)
318 queue_work(pool->wq, &pool->worker);
321 /*----------------------------------------------------------------*/
323 static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
324 struct dm_bio_prison_cell **cell_result)
327 struct dm_bio_prison_cell *cell_prealloc;
330 * Allocate a cell from the prison's mempool.
331 * This might block but it can't fail.
333 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
335 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
338 * We reused an old cell; we can get rid of
341 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
346 static void cell_release(struct pool *pool,
347 struct dm_bio_prison_cell *cell,
348 struct bio_list *bios)
350 dm_cell_release(pool->prison, cell, bios);
351 dm_bio_prison_free_cell(pool->prison, cell);
354 static void cell_visit_release(struct pool *pool,
355 void (*fn)(void *, struct dm_bio_prison_cell *),
357 struct dm_bio_prison_cell *cell)
359 dm_cell_visit_release(pool->prison, fn, context, cell);
360 dm_bio_prison_free_cell(pool->prison, cell);
363 static void cell_release_no_holder(struct pool *pool,
364 struct dm_bio_prison_cell *cell,
365 struct bio_list *bios)
367 dm_cell_release_no_holder(pool->prison, cell, bios);
368 dm_bio_prison_free_cell(pool->prison, cell);
371 static void cell_error_with_code(struct pool *pool,
372 struct dm_bio_prison_cell *cell, int error_code)
374 dm_cell_error(pool->prison, cell, error_code);
375 dm_bio_prison_free_cell(pool->prison, cell);
378 static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
380 cell_error_with_code(pool, cell, -EIO);
383 static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
385 cell_error_with_code(pool, cell, 0);
388 static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
390 cell_error_with_code(pool, cell, DM_ENDIO_REQUEUE);
393 /*----------------------------------------------------------------*/
396 * A global list of pools that uses a struct mapped_device as a key.
398 static struct dm_thin_pool_table {
400 struct list_head pools;
401 } dm_thin_pool_table;
403 static void pool_table_init(void)
405 mutex_init(&dm_thin_pool_table.mutex);
406 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
409 static void __pool_table_insert(struct pool *pool)
411 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
412 list_add(&pool->list, &dm_thin_pool_table.pools);
415 static void __pool_table_remove(struct pool *pool)
417 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
418 list_del(&pool->list);
421 static struct pool *__pool_table_lookup(struct mapped_device *md)
423 struct pool *pool = NULL, *tmp;
425 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
427 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
428 if (tmp->pool_md == md) {
437 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
439 struct pool *pool = NULL, *tmp;
441 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
443 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
444 if (tmp->md_dev == md_dev) {
453 /*----------------------------------------------------------------*/
455 struct dm_thin_endio_hook {
457 struct dm_deferred_entry *shared_read_entry;
458 struct dm_deferred_entry *all_io_entry;
459 struct dm_thin_new_mapping *overwrite_mapping;
460 struct rb_node rb_node;
463 static void __merge_bio_list(struct bio_list *bios, struct bio_list *master)
465 bio_list_merge(bios, master);
466 bio_list_init(master);
469 static void error_bio_list(struct bio_list *bios, int error)
473 while ((bio = bio_list_pop(bios)))
474 bio_endio(bio, error);
477 static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master, int error)
479 struct bio_list bios;
482 bio_list_init(&bios);
484 spin_lock_irqsave(&tc->lock, flags);
485 __merge_bio_list(&bios, master);
486 spin_unlock_irqrestore(&tc->lock, flags);
488 error_bio_list(&bios, error);
491 static void requeue_deferred_cells(struct thin_c *tc)
493 struct pool *pool = tc->pool;
495 struct list_head cells;
496 struct dm_bio_prison_cell *cell, *tmp;
498 INIT_LIST_HEAD(&cells);
500 spin_lock_irqsave(&tc->lock, flags);
501 list_splice_init(&tc->deferred_cells, &cells);
502 spin_unlock_irqrestore(&tc->lock, flags);
504 list_for_each_entry_safe(cell, tmp, &cells, user_list)
505 cell_requeue(pool, cell);
508 static void requeue_io(struct thin_c *tc)
510 struct bio_list bios;
513 bio_list_init(&bios);
515 spin_lock_irqsave(&tc->lock, flags);
516 __merge_bio_list(&bios, &tc->deferred_bio_list);
517 __merge_bio_list(&bios, &tc->retry_on_resume_list);
518 spin_unlock_irqrestore(&tc->lock, flags);
520 error_bio_list(&bios, DM_ENDIO_REQUEUE);
521 requeue_deferred_cells(tc);
524 static void error_retry_list(struct pool *pool)
529 list_for_each_entry_rcu(tc, &pool->active_thins, list)
530 error_thin_bio_list(tc, &tc->retry_on_resume_list, -EIO);
535 * This section of code contains the logic for processing a thin device's IO.
536 * Much of the code depends on pool object resources (lists, workqueues, etc)
537 * but most is exclusively called from the thin target rather than the thin-pool
541 static bool block_size_is_power_of_two(struct pool *pool)
543 return pool->sectors_per_block_shift >= 0;
546 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
548 struct pool *pool = tc->pool;
549 sector_t block_nr = bio->bi_iter.bi_sector;
551 if (block_size_is_power_of_two(pool))
552 block_nr >>= pool->sectors_per_block_shift;
554 (void) sector_div(block_nr, pool->sectors_per_block);
559 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
561 struct pool *pool = tc->pool;
562 sector_t bi_sector = bio->bi_iter.bi_sector;
564 bio->bi_bdev = tc->pool_dev->bdev;
565 if (block_size_is_power_of_two(pool))
566 bio->bi_iter.bi_sector =
567 (block << pool->sectors_per_block_shift) |
568 (bi_sector & (pool->sectors_per_block - 1));
570 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
571 sector_div(bi_sector, pool->sectors_per_block);
574 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
576 bio->bi_bdev = tc->origin_dev->bdev;
579 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
581 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
582 dm_thin_changed_this_transaction(tc->td);
585 static void inc_all_io_entry(struct pool *pool, struct bio *bio)
587 struct dm_thin_endio_hook *h;
589 if (bio->bi_rw & REQ_DISCARD)
592 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
593 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
596 static void issue(struct thin_c *tc, struct bio *bio)
598 struct pool *pool = tc->pool;
601 if (!bio_triggers_commit(tc, bio)) {
602 generic_make_request(bio);
607 * Complete bio with an error if earlier I/O caused changes to
608 * the metadata that can't be committed e.g, due to I/O errors
609 * on the metadata device.
611 if (dm_thin_aborted_changes(tc->td)) {
617 * Batch together any bios that trigger commits and then issue a
618 * single commit for them in process_deferred_bios().
620 spin_lock_irqsave(&pool->lock, flags);
621 bio_list_add(&pool->deferred_flush_bios, bio);
622 spin_unlock_irqrestore(&pool->lock, flags);
625 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
627 remap_to_origin(tc, bio);
631 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
634 remap(tc, bio, block);
638 /*----------------------------------------------------------------*/
641 * Bio endio functions.
643 struct dm_thin_new_mapping {
644 struct list_head list;
647 bool definitely_not_shared:1;
650 * Track quiescing, copying and zeroing preparation actions. When this
651 * counter hits zero the block is prepared and can be inserted into the
654 atomic_t prepare_actions;
658 dm_block_t virt_block;
659 dm_block_t data_block;
660 struct dm_bio_prison_cell *cell, *cell2;
663 * If the bio covers the whole area of a block then we can avoid
664 * zeroing or copying. Instead this bio is hooked. The bio will
665 * still be in the cell, so care has to be taken to avoid issuing
669 bio_end_io_t *saved_bi_end_io;
672 static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
674 struct pool *pool = m->tc->pool;
676 if (atomic_dec_and_test(&m->prepare_actions)) {
677 list_add_tail(&m->list, &pool->prepared_mappings);
682 static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
685 struct pool *pool = m->tc->pool;
687 spin_lock_irqsave(&pool->lock, flags);
688 __complete_mapping_preparation(m);
689 spin_unlock_irqrestore(&pool->lock, flags);
692 static void copy_complete(int read_err, unsigned long write_err, void *context)
694 struct dm_thin_new_mapping *m = context;
696 m->err = read_err || write_err ? -EIO : 0;
697 complete_mapping_preparation(m);
700 static void overwrite_endio(struct bio *bio, int err)
702 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
703 struct dm_thin_new_mapping *m = h->overwrite_mapping;
706 complete_mapping_preparation(m);
709 /*----------------------------------------------------------------*/
716 * Prepared mapping jobs.
720 * This sends the bios in the cell, except the original holder, back
721 * to the deferred_bios list.
723 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
725 struct pool *pool = tc->pool;
728 spin_lock_irqsave(&tc->lock, flags);
729 cell_release_no_holder(pool, cell, &tc->deferred_bio_list);
730 spin_unlock_irqrestore(&tc->lock, flags);
735 static void thin_defer_bio(struct thin_c *tc, struct bio *bio);
739 struct bio_list defer_bios;
740 struct bio_list issue_bios;
743 static void __inc_remap_and_issue_cell(void *context,
744 struct dm_bio_prison_cell *cell)
746 struct remap_info *info = context;
749 while ((bio = bio_list_pop(&cell->bios))) {
750 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA))
751 bio_list_add(&info->defer_bios, bio);
753 inc_all_io_entry(info->tc->pool, bio);
756 * We can't issue the bios with the bio prison lock
757 * held, so we add them to a list to issue on
758 * return from this function.
760 bio_list_add(&info->issue_bios, bio);
765 static void inc_remap_and_issue_cell(struct thin_c *tc,
766 struct dm_bio_prison_cell *cell,
770 struct remap_info info;
773 bio_list_init(&info.defer_bios);
774 bio_list_init(&info.issue_bios);
777 * We have to be careful to inc any bios we're about to issue
778 * before the cell is released, and avoid a race with new bios
779 * being added to the cell.
781 cell_visit_release(tc->pool, __inc_remap_and_issue_cell,
784 while ((bio = bio_list_pop(&info.defer_bios)))
785 thin_defer_bio(tc, bio);
787 while ((bio = bio_list_pop(&info.issue_bios)))
788 remap_and_issue(info.tc, bio, block);
791 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
794 m->bio->bi_end_io = m->saved_bi_end_io;
795 atomic_inc(&m->bio->bi_remaining);
797 cell_error(m->tc->pool, m->cell);
799 mempool_free(m, m->tc->pool->mapping_pool);
802 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
804 struct thin_c *tc = m->tc;
805 struct pool *pool = tc->pool;
811 bio->bi_end_io = m->saved_bi_end_io;
812 atomic_inc(&bio->bi_remaining);
816 cell_error(pool, m->cell);
821 * Commit the prepared block into the mapping btree.
822 * Any I/O for this block arriving after this point will get
823 * remapped to it directly.
825 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
827 metadata_operation_failed(pool, "dm_thin_insert_block", r);
828 cell_error(pool, m->cell);
833 * Release any bios held while the block was being provisioned.
834 * If we are processing a write bio that completely covers the block,
835 * we already processed it so can ignore it now when processing
836 * the bios in the cell.
839 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
842 inc_all_io_entry(tc->pool, m->cell->holder);
843 remap_and_issue(tc, m->cell->holder, m->data_block);
844 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
849 mempool_free(m, pool->mapping_pool);
852 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
854 struct thin_c *tc = m->tc;
856 bio_io_error(m->bio);
857 cell_defer_no_holder(tc, m->cell);
858 cell_defer_no_holder(tc, m->cell2);
859 mempool_free(m, tc->pool->mapping_pool);
862 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
864 struct thin_c *tc = m->tc;
866 inc_all_io_entry(tc->pool, m->bio);
867 cell_defer_no_holder(tc, m->cell);
868 cell_defer_no_holder(tc, m->cell2);
871 if (m->definitely_not_shared)
872 remap_and_issue(tc, m->bio, m->data_block);
875 if (dm_pool_block_is_used(tc->pool->pmd, m->data_block, &used) || used)
876 bio_endio(m->bio, 0);
878 remap_and_issue(tc, m->bio, m->data_block);
881 bio_endio(m->bio, 0);
883 mempool_free(m, tc->pool->mapping_pool);
886 static void process_prepared_discard(struct dm_thin_new_mapping *m)
889 struct thin_c *tc = m->tc;
891 r = dm_thin_remove_block(tc->td, m->virt_block);
893 DMERR_LIMIT("dm_thin_remove_block() failed");
895 process_prepared_discard_passdown(m);
898 static void process_prepared(struct pool *pool, struct list_head *head,
899 process_mapping_fn *fn)
902 struct list_head maps;
903 struct dm_thin_new_mapping *m, *tmp;
905 INIT_LIST_HEAD(&maps);
906 spin_lock_irqsave(&pool->lock, flags);
907 list_splice_init(head, &maps);
908 spin_unlock_irqrestore(&pool->lock, flags);
910 list_for_each_entry_safe(m, tmp, &maps, list)
917 static int io_overlaps_block(struct pool *pool, struct bio *bio)
919 return bio->bi_iter.bi_size ==
920 (pool->sectors_per_block << SECTOR_SHIFT);
923 static int io_overwrites_block(struct pool *pool, struct bio *bio)
925 return (bio_data_dir(bio) == WRITE) &&
926 io_overlaps_block(pool, bio);
929 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
932 *save = bio->bi_end_io;
936 static int ensure_next_mapping(struct pool *pool)
938 if (pool->next_mapping)
941 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
943 return pool->next_mapping ? 0 : -ENOMEM;
946 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
948 struct dm_thin_new_mapping *m = pool->next_mapping;
950 BUG_ON(!pool->next_mapping);
952 memset(m, 0, sizeof(struct dm_thin_new_mapping));
953 INIT_LIST_HEAD(&m->list);
956 pool->next_mapping = NULL;
961 static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
962 sector_t begin, sector_t end)
965 struct dm_io_region to;
967 to.bdev = tc->pool_dev->bdev;
969 to.count = end - begin;
971 r = dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
973 DMERR_LIMIT("dm_kcopyd_zero() failed");
974 copy_complete(1, 1, m);
978 static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
979 dm_block_t data_block,
980 struct dm_thin_new_mapping *m)
982 struct pool *pool = tc->pool;
983 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
985 h->overwrite_mapping = m;
987 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
988 inc_all_io_entry(pool, bio);
989 remap_and_issue(tc, bio, data_block);
993 * A partial copy also needs to zero the uncopied region.
995 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
996 struct dm_dev *origin, dm_block_t data_origin,
997 dm_block_t data_dest,
998 struct dm_bio_prison_cell *cell, struct bio *bio,
1002 struct pool *pool = tc->pool;
1003 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1006 m->virt_block = virt_block;
1007 m->data_block = data_dest;
1011 * quiesce action + copy action + an extra reference held for the
1012 * duration of this function (we may need to inc later for a
1015 atomic_set(&m->prepare_actions, 3);
1017 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
1018 complete_mapping_preparation(m); /* already quiesced */
1021 * IO to pool_dev remaps to the pool target's data_dev.
1023 * If the whole block of data is being overwritten, we can issue the
1024 * bio immediately. Otherwise we use kcopyd to clone the data first.
1026 if (io_overwrites_block(pool, bio))
1027 remap_and_issue_overwrite(tc, bio, data_dest, m);
1029 struct dm_io_region from, to;
1031 from.bdev = origin->bdev;
1032 from.sector = data_origin * pool->sectors_per_block;
1035 to.bdev = tc->pool_dev->bdev;
1036 to.sector = data_dest * pool->sectors_per_block;
1039 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
1040 0, copy_complete, m);
1042 DMERR_LIMIT("dm_kcopyd_copy() failed");
1043 copy_complete(1, 1, m);
1046 * We allow the zero to be issued, to simplify the
1047 * error path. Otherwise we'd need to start
1048 * worrying about decrementing the prepare_actions
1054 * Do we need to zero a tail region?
1056 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
1057 atomic_inc(&m->prepare_actions);
1059 data_dest * pool->sectors_per_block + len,
1060 (data_dest + 1) * pool->sectors_per_block);
1064 complete_mapping_preparation(m); /* drop our ref */
1067 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
1068 dm_block_t data_origin, dm_block_t data_dest,
1069 struct dm_bio_prison_cell *cell, struct bio *bio)
1071 schedule_copy(tc, virt_block, tc->pool_dev,
1072 data_origin, data_dest, cell, bio,
1073 tc->pool->sectors_per_block);
1076 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
1077 dm_block_t data_block, struct dm_bio_prison_cell *cell,
1080 struct pool *pool = tc->pool;
1081 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1083 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
1085 m->virt_block = virt_block;
1086 m->data_block = data_block;
1090 * If the whole block of data is being overwritten or we are not
1091 * zeroing pre-existing data, we can issue the bio immediately.
1092 * Otherwise we use kcopyd to zero the data first.
1094 if (!pool->pf.zero_new_blocks)
1095 process_prepared_mapping(m);
1097 else if (io_overwrites_block(pool, bio))
1098 remap_and_issue_overwrite(tc, bio, data_block, m);
1102 data_block * pool->sectors_per_block,
1103 (data_block + 1) * pool->sectors_per_block);
1106 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1107 dm_block_t data_dest,
1108 struct dm_bio_prison_cell *cell, struct bio *bio)
1110 struct pool *pool = tc->pool;
1111 sector_t virt_block_begin = virt_block * pool->sectors_per_block;
1112 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
1114 if (virt_block_end <= tc->origin_size)
1115 schedule_copy(tc, virt_block, tc->origin_dev,
1116 virt_block, data_dest, cell, bio,
1117 pool->sectors_per_block);
1119 else if (virt_block_begin < tc->origin_size)
1120 schedule_copy(tc, virt_block, tc->origin_dev,
1121 virt_block, data_dest, cell, bio,
1122 tc->origin_size - virt_block_begin);
1125 schedule_zero(tc, virt_block, data_dest, cell, bio);
1129 * A non-zero return indicates read_only or fail_io mode.
1130 * Many callers don't care about the return value.
1132 static int commit(struct pool *pool)
1136 if (get_pool_mode(pool) >= PM_READ_ONLY)
1139 r = dm_pool_commit_metadata(pool->pmd);
1141 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
1146 static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
1148 unsigned long flags;
1150 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1151 DMWARN("%s: reached low water mark for data device: sending event.",
1152 dm_device_name(pool->pool_md));
1153 spin_lock_irqsave(&pool->lock, flags);
1154 pool->low_water_triggered = true;
1155 spin_unlock_irqrestore(&pool->lock, flags);
1156 dm_table_event(pool->ti->table);
1160 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
1162 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1165 dm_block_t free_blocks;
1166 struct pool *pool = tc->pool;
1168 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
1171 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1173 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1177 check_low_water_mark(pool, free_blocks);
1181 * Try to commit to see if that will free up some
1188 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1190 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1195 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1200 r = dm_pool_alloc_data_block(pool->pmd, result);
1202 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1210 * If we have run out of space, queue bios until the device is
1211 * resumed, presumably after having been reloaded with more space.
1213 static void retry_on_resume(struct bio *bio)
1215 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1216 struct thin_c *tc = h->tc;
1217 unsigned long flags;
1219 spin_lock_irqsave(&tc->lock, flags);
1220 bio_list_add(&tc->retry_on_resume_list, bio);
1221 spin_unlock_irqrestore(&tc->lock, flags);
1224 static int should_error_unserviceable_bio(struct pool *pool)
1226 enum pool_mode m = get_pool_mode(pool);
1230 /* Shouldn't get here */
1231 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1234 case PM_OUT_OF_DATA_SPACE:
1235 return pool->pf.error_if_no_space ? -ENOSPC : 0;
1241 /* Shouldn't get here */
1242 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1247 static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1249 int error = should_error_unserviceable_bio(pool);
1252 bio_endio(bio, error);
1254 retry_on_resume(bio);
1257 static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1260 struct bio_list bios;
1263 error = should_error_unserviceable_bio(pool);
1265 cell_error_with_code(pool, cell, error);
1269 bio_list_init(&bios);
1270 cell_release(pool, cell, &bios);
1272 while ((bio = bio_list_pop(&bios)))
1273 retry_on_resume(bio);
1276 static void process_discard_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1279 struct bio *bio = cell->holder;
1280 struct pool *pool = tc->pool;
1281 struct dm_bio_prison_cell *cell2;
1282 struct dm_cell_key key2;
1283 dm_block_t block = get_bio_block(tc, bio);
1284 struct dm_thin_lookup_result lookup_result;
1285 struct dm_thin_new_mapping *m;
1287 if (tc->requeue_mode) {
1288 cell_requeue(pool, cell);
1292 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1296 * Check nobody is fiddling with this pool block. This can
1297 * happen if someone's in the process of breaking sharing
1300 build_data_key(tc->td, lookup_result.block, &key2);
1301 if (bio_detain(tc->pool, &key2, bio, &cell2)) {
1302 cell_defer_no_holder(tc, cell);
1306 if (io_overlaps_block(pool, bio)) {
1308 * IO may still be going to the destination block. We must
1309 * quiesce before we can do the removal.
1311 m = get_next_mapping(pool);
1313 m->pass_discard = pool->pf.discard_passdown;
1314 m->definitely_not_shared = !lookup_result.shared;
1315 m->virt_block = block;
1316 m->data_block = lookup_result.block;
1321 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1322 pool->process_prepared_discard(m);
1325 inc_all_io_entry(pool, bio);
1326 cell_defer_no_holder(tc, cell);
1327 cell_defer_no_holder(tc, cell2);
1330 * The DM core makes sure that the discard doesn't span
1331 * a block boundary. So we submit the discard of a
1332 * partial block appropriately.
1334 if ((!lookup_result.shared) && pool->pf.discard_passdown)
1335 remap_and_issue(tc, bio, lookup_result.block);
1343 * It isn't provisioned, just forget it.
1345 cell_defer_no_holder(tc, cell);
1350 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1352 cell_defer_no_holder(tc, cell);
1358 static void process_discard_bio(struct thin_c *tc, struct bio *bio)
1360 struct dm_bio_prison_cell *cell;
1361 struct dm_cell_key key;
1362 dm_block_t block = get_bio_block(tc, bio);
1364 build_virtual_key(tc->td, block, &key);
1365 if (bio_detain(tc->pool, &key, bio, &cell))
1368 process_discard_cell(tc, cell);
1371 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1372 struct dm_cell_key *key,
1373 struct dm_thin_lookup_result *lookup_result,
1374 struct dm_bio_prison_cell *cell)
1377 dm_block_t data_block;
1378 struct pool *pool = tc->pool;
1380 r = alloc_data_block(tc, &data_block);
1383 schedule_internal_copy(tc, block, lookup_result->block,
1384 data_block, cell, bio);
1388 retry_bios_on_resume(pool, cell);
1392 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1394 cell_error(pool, cell);
1399 static void __remap_and_issue_shared_cell(void *context,
1400 struct dm_bio_prison_cell *cell)
1402 struct remap_info *info = context;
1405 while ((bio = bio_list_pop(&cell->bios))) {
1406 if ((bio_data_dir(bio) == WRITE) ||
1407 (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)))
1408 bio_list_add(&info->defer_bios, bio);
1410 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));;
1412 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds);
1413 inc_all_io_entry(info->tc->pool, bio);
1414 bio_list_add(&info->issue_bios, bio);
1419 static void remap_and_issue_shared_cell(struct thin_c *tc,
1420 struct dm_bio_prison_cell *cell,
1424 struct remap_info info;
1427 bio_list_init(&info.defer_bios);
1428 bio_list_init(&info.issue_bios);
1430 cell_visit_release(tc->pool, __remap_and_issue_shared_cell,
1433 while ((bio = bio_list_pop(&info.defer_bios)))
1434 thin_defer_bio(tc, bio);
1436 while ((bio = bio_list_pop(&info.issue_bios)))
1437 remap_and_issue(tc, bio, block);
1440 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1442 struct dm_thin_lookup_result *lookup_result,
1443 struct dm_bio_prison_cell *virt_cell)
1445 struct dm_bio_prison_cell *data_cell;
1446 struct pool *pool = tc->pool;
1447 struct dm_cell_key key;
1450 * If cell is already occupied, then sharing is already in the process
1451 * of being broken so we have nothing further to do here.
1453 build_data_key(tc->td, lookup_result->block, &key);
1454 if (bio_detain(pool, &key, bio, &data_cell)) {
1455 cell_defer_no_holder(tc, virt_cell);
1459 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) {
1460 break_sharing(tc, bio, block, &key, lookup_result, data_cell);
1461 cell_defer_no_holder(tc, virt_cell);
1463 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1465 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1466 inc_all_io_entry(pool, bio);
1467 remap_and_issue(tc, bio, lookup_result->block);
1469 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block);
1470 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block);
1474 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1475 struct dm_bio_prison_cell *cell)
1478 dm_block_t data_block;
1479 struct pool *pool = tc->pool;
1482 * Remap empty bios (flushes) immediately, without provisioning.
1484 if (!bio->bi_iter.bi_size) {
1485 inc_all_io_entry(pool, bio);
1486 cell_defer_no_holder(tc, cell);
1488 remap_and_issue(tc, bio, 0);
1493 * Fill read bios with zeroes and complete them immediately.
1495 if (bio_data_dir(bio) == READ) {
1497 cell_defer_no_holder(tc, cell);
1502 r = alloc_data_block(tc, &data_block);
1506 schedule_external_copy(tc, block, data_block, cell, bio);
1508 schedule_zero(tc, block, data_block, cell, bio);
1512 retry_bios_on_resume(pool, cell);
1516 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1518 cell_error(pool, cell);
1523 static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1526 struct pool *pool = tc->pool;
1527 struct bio *bio = cell->holder;
1528 dm_block_t block = get_bio_block(tc, bio);
1529 struct dm_thin_lookup_result lookup_result;
1531 if (tc->requeue_mode) {
1532 cell_requeue(pool, cell);
1536 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1539 if (lookup_result.shared)
1540 process_shared_bio(tc, bio, block, &lookup_result, cell);
1542 inc_all_io_entry(pool, bio);
1543 remap_and_issue(tc, bio, lookup_result.block);
1544 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1549 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1550 inc_all_io_entry(pool, bio);
1551 cell_defer_no_holder(tc, cell);
1553 if (bio_end_sector(bio) <= tc->origin_size)
1554 remap_to_origin_and_issue(tc, bio);
1556 else if (bio->bi_iter.bi_sector < tc->origin_size) {
1558 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
1559 remap_to_origin_and_issue(tc, bio);
1566 provision_block(tc, bio, block, cell);
1570 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1572 cell_defer_no_holder(tc, cell);
1578 static void process_bio(struct thin_c *tc, struct bio *bio)
1580 struct pool *pool = tc->pool;
1581 dm_block_t block = get_bio_block(tc, bio);
1582 struct dm_bio_prison_cell *cell;
1583 struct dm_cell_key key;
1586 * If cell is already occupied, then the block is already
1587 * being provisioned so we have nothing further to do here.
1589 build_virtual_key(tc->td, block, &key);
1590 if (bio_detain(pool, &key, bio, &cell))
1593 process_cell(tc, cell);
1596 static void __process_bio_read_only(struct thin_c *tc, struct bio *bio,
1597 struct dm_bio_prison_cell *cell)
1600 int rw = bio_data_dir(bio);
1601 dm_block_t block = get_bio_block(tc, bio);
1602 struct dm_thin_lookup_result lookup_result;
1604 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1607 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) {
1608 handle_unserviceable_bio(tc->pool, bio);
1610 cell_defer_no_holder(tc, cell);
1612 inc_all_io_entry(tc->pool, bio);
1613 remap_and_issue(tc, bio, lookup_result.block);
1615 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1621 cell_defer_no_holder(tc, cell);
1623 handle_unserviceable_bio(tc->pool, bio);
1627 if (tc->origin_dev) {
1628 inc_all_io_entry(tc->pool, bio);
1629 remap_to_origin_and_issue(tc, bio);
1638 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1641 cell_defer_no_holder(tc, cell);
1647 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1649 __process_bio_read_only(tc, bio, NULL);
1652 static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1654 __process_bio_read_only(tc, cell->holder, cell);
1657 static void process_bio_success(struct thin_c *tc, struct bio *bio)
1662 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1667 static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1669 cell_success(tc->pool, cell);
1672 static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1674 cell_error(tc->pool, cell);
1678 * FIXME: should we also commit due to size of transaction, measured in
1681 static int need_commit_due_to_time(struct pool *pool)
1683 return jiffies < pool->last_commit_jiffies ||
1684 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1687 #define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
1688 #define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
1690 static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
1692 struct rb_node **rbp, *parent;
1693 struct dm_thin_endio_hook *pbd;
1694 sector_t bi_sector = bio->bi_iter.bi_sector;
1696 rbp = &tc->sort_bio_list.rb_node;
1700 pbd = thin_pbd(parent);
1702 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
1703 rbp = &(*rbp)->rb_left;
1705 rbp = &(*rbp)->rb_right;
1708 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1709 rb_link_node(&pbd->rb_node, parent, rbp);
1710 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
1713 static void __extract_sorted_bios(struct thin_c *tc)
1715 struct rb_node *node;
1716 struct dm_thin_endio_hook *pbd;
1719 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
1720 pbd = thin_pbd(node);
1721 bio = thin_bio(pbd);
1723 bio_list_add(&tc->deferred_bio_list, bio);
1724 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
1727 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
1730 static void __sort_thin_deferred_bios(struct thin_c *tc)
1733 struct bio_list bios;
1735 bio_list_init(&bios);
1736 bio_list_merge(&bios, &tc->deferred_bio_list);
1737 bio_list_init(&tc->deferred_bio_list);
1739 /* Sort deferred_bio_list using rb-tree */
1740 while ((bio = bio_list_pop(&bios)))
1741 __thin_bio_rb_add(tc, bio);
1744 * Transfer the sorted bios in sort_bio_list back to
1745 * deferred_bio_list to allow lockless submission of
1748 __extract_sorted_bios(tc);
1751 static void process_thin_deferred_bios(struct thin_c *tc)
1753 struct pool *pool = tc->pool;
1754 unsigned long flags;
1756 struct bio_list bios;
1757 struct blk_plug plug;
1760 if (tc->requeue_mode) {
1761 error_thin_bio_list(tc, &tc->deferred_bio_list, DM_ENDIO_REQUEUE);
1765 bio_list_init(&bios);
1767 spin_lock_irqsave(&tc->lock, flags);
1769 if (bio_list_empty(&tc->deferred_bio_list)) {
1770 spin_unlock_irqrestore(&tc->lock, flags);
1774 __sort_thin_deferred_bios(tc);
1776 bio_list_merge(&bios, &tc->deferred_bio_list);
1777 bio_list_init(&tc->deferred_bio_list);
1779 spin_unlock_irqrestore(&tc->lock, flags);
1781 blk_start_plug(&plug);
1782 while ((bio = bio_list_pop(&bios))) {
1784 * If we've got no free new_mapping structs, and processing
1785 * this bio might require one, we pause until there are some
1786 * prepared mappings to process.
1788 if (ensure_next_mapping(pool)) {
1789 spin_lock_irqsave(&tc->lock, flags);
1790 bio_list_add(&tc->deferred_bio_list, bio);
1791 bio_list_merge(&tc->deferred_bio_list, &bios);
1792 spin_unlock_irqrestore(&tc->lock, flags);
1796 if (bio->bi_rw & REQ_DISCARD)
1797 pool->process_discard(tc, bio);
1799 pool->process_bio(tc, bio);
1801 if ((count++ & 127) == 0) {
1802 throttle_work_update(&pool->throttle);
1803 dm_pool_issue_prefetches(pool->pmd);
1806 blk_finish_plug(&plug);
1809 static int cmp_cells(const void *lhs, const void *rhs)
1811 struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs);
1812 struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs);
1814 BUG_ON(!lhs_cell->holder);
1815 BUG_ON(!rhs_cell->holder);
1817 if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector)
1820 if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector)
1826 static unsigned sort_cells(struct pool *pool, struct list_head *cells)
1829 struct dm_bio_prison_cell *cell, *tmp;
1831 list_for_each_entry_safe(cell, tmp, cells, user_list) {
1832 if (count >= CELL_SORT_ARRAY_SIZE)
1835 pool->cell_sort_array[count++] = cell;
1836 list_del(&cell->user_list);
1839 sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL);
1844 static void process_thin_deferred_cells(struct thin_c *tc)
1846 struct pool *pool = tc->pool;
1847 unsigned long flags;
1848 struct list_head cells;
1849 struct dm_bio_prison_cell *cell;
1850 unsigned i, j, count;
1852 INIT_LIST_HEAD(&cells);
1854 spin_lock_irqsave(&tc->lock, flags);
1855 list_splice_init(&tc->deferred_cells, &cells);
1856 spin_unlock_irqrestore(&tc->lock, flags);
1858 if (list_empty(&cells))
1862 count = sort_cells(tc->pool, &cells);
1864 for (i = 0; i < count; i++) {
1865 cell = pool->cell_sort_array[i];
1866 BUG_ON(!cell->holder);
1869 * If we've got no free new_mapping structs, and processing
1870 * this bio might require one, we pause until there are some
1871 * prepared mappings to process.
1873 if (ensure_next_mapping(pool)) {
1874 for (j = i; j < count; j++)
1875 list_add(&pool->cell_sort_array[j]->user_list, &cells);
1877 spin_lock_irqsave(&tc->lock, flags);
1878 list_splice(&cells, &tc->deferred_cells);
1879 spin_unlock_irqrestore(&tc->lock, flags);
1883 if (cell->holder->bi_rw & REQ_DISCARD)
1884 pool->process_discard_cell(tc, cell);
1886 pool->process_cell(tc, cell);
1888 } while (!list_empty(&cells));
1891 static void thin_get(struct thin_c *tc);
1892 static void thin_put(struct thin_c *tc);
1895 * We can't hold rcu_read_lock() around code that can block. So we
1896 * find a thin with the rcu lock held; bump a refcount; then drop
1899 static struct thin_c *get_first_thin(struct pool *pool)
1901 struct thin_c *tc = NULL;
1904 if (!list_empty(&pool->active_thins)) {
1905 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
1913 static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
1915 struct thin_c *old_tc = tc;
1918 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
1930 static void process_deferred_bios(struct pool *pool)
1932 unsigned long flags;
1934 struct bio_list bios;
1937 tc = get_first_thin(pool);
1939 process_thin_deferred_cells(tc);
1940 process_thin_deferred_bios(tc);
1941 tc = get_next_thin(pool, tc);
1945 * If there are any deferred flush bios, we must commit
1946 * the metadata before issuing them.
1948 bio_list_init(&bios);
1949 spin_lock_irqsave(&pool->lock, flags);
1950 bio_list_merge(&bios, &pool->deferred_flush_bios);
1951 bio_list_init(&pool->deferred_flush_bios);
1952 spin_unlock_irqrestore(&pool->lock, flags);
1954 if (bio_list_empty(&bios) &&
1955 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
1959 while ((bio = bio_list_pop(&bios)))
1963 pool->last_commit_jiffies = jiffies;
1965 while ((bio = bio_list_pop(&bios)))
1966 generic_make_request(bio);
1969 static void do_worker(struct work_struct *ws)
1971 struct pool *pool = container_of(ws, struct pool, worker);
1973 throttle_work_start(&pool->throttle);
1974 dm_pool_issue_prefetches(pool->pmd);
1975 throttle_work_update(&pool->throttle);
1976 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1977 throttle_work_update(&pool->throttle);
1978 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1979 throttle_work_update(&pool->throttle);
1980 process_deferred_bios(pool);
1981 throttle_work_complete(&pool->throttle);
1985 * We want to commit periodically so that not too much
1986 * unwritten data builds up.
1988 static void do_waker(struct work_struct *ws)
1990 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1992 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1996 * We're holding onto IO to allow userland time to react. After the
1997 * timeout either the pool will have been resized (and thus back in
1998 * PM_WRITE mode), or we degrade to PM_READ_ONLY and start erroring IO.
2000 static void do_no_space_timeout(struct work_struct *ws)
2002 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
2005 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space)
2006 set_pool_mode(pool, PM_READ_ONLY);
2009 /*----------------------------------------------------------------*/
2012 struct work_struct worker;
2013 struct completion complete;
2016 static struct pool_work *to_pool_work(struct work_struct *ws)
2018 return container_of(ws, struct pool_work, worker);
2021 static void pool_work_complete(struct pool_work *pw)
2023 complete(&pw->complete);
2026 static void pool_work_wait(struct pool_work *pw, struct pool *pool,
2027 void (*fn)(struct work_struct *))
2029 INIT_WORK_ONSTACK(&pw->worker, fn);
2030 init_completion(&pw->complete);
2031 queue_work(pool->wq, &pw->worker);
2032 wait_for_completion(&pw->complete);
2035 /*----------------------------------------------------------------*/
2037 struct noflush_work {
2038 struct pool_work pw;
2042 static struct noflush_work *to_noflush(struct work_struct *ws)
2044 return container_of(to_pool_work(ws), struct noflush_work, pw);
2047 static void do_noflush_start(struct work_struct *ws)
2049 struct noflush_work *w = to_noflush(ws);
2050 w->tc->requeue_mode = true;
2052 pool_work_complete(&w->pw);
2055 static void do_noflush_stop(struct work_struct *ws)
2057 struct noflush_work *w = to_noflush(ws);
2058 w->tc->requeue_mode = false;
2059 pool_work_complete(&w->pw);
2062 static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
2064 struct noflush_work w;
2067 pool_work_wait(&w.pw, tc->pool, fn);
2070 /*----------------------------------------------------------------*/
2072 static enum pool_mode get_pool_mode(struct pool *pool)
2074 return pool->pf.mode;
2077 static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode)
2079 dm_table_event(pool->ti->table);
2080 DMINFO("%s: switching pool to %s mode",
2081 dm_device_name(pool->pool_md), new_mode);
2084 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
2086 struct pool_c *pt = pool->ti->private;
2087 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
2088 enum pool_mode old_mode = get_pool_mode(pool);
2089 unsigned long no_space_timeout = ACCESS_ONCE(no_space_timeout_secs) * HZ;
2092 * Never allow the pool to transition to PM_WRITE mode if user
2093 * intervention is required to verify metadata and data consistency.
2095 if (new_mode == PM_WRITE && needs_check) {
2096 DMERR("%s: unable to switch pool to write mode until repaired.",
2097 dm_device_name(pool->pool_md));
2098 if (old_mode != new_mode)
2099 new_mode = old_mode;
2101 new_mode = PM_READ_ONLY;
2104 * If we were in PM_FAIL mode, rollback of metadata failed. We're
2105 * not going to recover without a thin_repair. So we never let the
2106 * pool move out of the old mode.
2108 if (old_mode == PM_FAIL)
2109 new_mode = old_mode;
2113 if (old_mode != new_mode)
2114 notify_of_pool_mode_change(pool, "failure");
2115 dm_pool_metadata_read_only(pool->pmd);
2116 pool->process_bio = process_bio_fail;
2117 pool->process_discard = process_bio_fail;
2118 pool->process_cell = process_cell_fail;
2119 pool->process_discard_cell = process_cell_fail;
2120 pool->process_prepared_mapping = process_prepared_mapping_fail;
2121 pool->process_prepared_discard = process_prepared_discard_fail;
2123 error_retry_list(pool);
2127 if (old_mode != new_mode)
2128 notify_of_pool_mode_change(pool, "read-only");
2129 dm_pool_metadata_read_only(pool->pmd);
2130 pool->process_bio = process_bio_read_only;
2131 pool->process_discard = process_bio_success;
2132 pool->process_cell = process_cell_read_only;
2133 pool->process_discard_cell = process_cell_success;
2134 pool->process_prepared_mapping = process_prepared_mapping_fail;
2135 pool->process_prepared_discard = process_prepared_discard_passdown;
2137 error_retry_list(pool);
2140 case PM_OUT_OF_DATA_SPACE:
2142 * Ideally we'd never hit this state; the low water mark
2143 * would trigger userland to extend the pool before we
2144 * completely run out of data space. However, many small
2145 * IOs to unprovisioned space can consume data space at an
2146 * alarming rate. Adjust your low water mark if you're
2147 * frequently seeing this mode.
2149 if (old_mode != new_mode)
2150 notify_of_pool_mode_change(pool, "out-of-data-space");
2151 pool->process_bio = process_bio_read_only;
2152 pool->process_discard = process_discard_bio;
2153 pool->process_cell = process_cell_read_only;
2154 pool->process_discard_cell = process_discard_cell;
2155 pool->process_prepared_mapping = process_prepared_mapping;
2156 pool->process_prepared_discard = process_prepared_discard_passdown;
2158 if (!pool->pf.error_if_no_space && no_space_timeout)
2159 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
2163 if (old_mode != new_mode)
2164 notify_of_pool_mode_change(pool, "write");
2165 dm_pool_metadata_read_write(pool->pmd);
2166 pool->process_bio = process_bio;
2167 pool->process_discard = process_discard_bio;
2168 pool->process_cell = process_cell;
2169 pool->process_discard_cell = process_discard_cell;
2170 pool->process_prepared_mapping = process_prepared_mapping;
2171 pool->process_prepared_discard = process_prepared_discard;
2175 pool->pf.mode = new_mode;
2177 * The pool mode may have changed, sync it so bind_control_target()
2178 * doesn't cause an unexpected mode transition on resume.
2180 pt->adjusted_pf.mode = new_mode;
2183 static void abort_transaction(struct pool *pool)
2185 const char *dev_name = dm_device_name(pool->pool_md);
2187 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
2188 if (dm_pool_abort_metadata(pool->pmd)) {
2189 DMERR("%s: failed to abort metadata transaction", dev_name);
2190 set_pool_mode(pool, PM_FAIL);
2193 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
2194 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
2195 set_pool_mode(pool, PM_FAIL);
2199 static void metadata_operation_failed(struct pool *pool, const char *op, int r)
2201 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
2202 dm_device_name(pool->pool_md), op, r);
2204 abort_transaction(pool);
2205 set_pool_mode(pool, PM_READ_ONLY);
2208 /*----------------------------------------------------------------*/
2211 * Mapping functions.
2215 * Called only while mapping a thin bio to hand it over to the workqueue.
2217 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
2219 unsigned long flags;
2220 struct pool *pool = tc->pool;
2222 spin_lock_irqsave(&tc->lock, flags);
2223 bio_list_add(&tc->deferred_bio_list, bio);
2224 spin_unlock_irqrestore(&tc->lock, flags);
2229 static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
2231 struct pool *pool = tc->pool;
2233 throttle_lock(&pool->throttle);
2234 thin_defer_bio(tc, bio);
2235 throttle_unlock(&pool->throttle);
2238 static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2240 unsigned long flags;
2241 struct pool *pool = tc->pool;
2243 throttle_lock(&pool->throttle);
2244 spin_lock_irqsave(&tc->lock, flags);
2245 list_add_tail(&cell->user_list, &tc->deferred_cells);
2246 spin_unlock_irqrestore(&tc->lock, flags);
2247 throttle_unlock(&pool->throttle);
2252 static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
2254 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2257 h->shared_read_entry = NULL;
2258 h->all_io_entry = NULL;
2259 h->overwrite_mapping = NULL;
2263 * Non-blocking function called from the thin target's map function.
2265 static int thin_bio_map(struct dm_target *ti, struct bio *bio)
2268 struct thin_c *tc = ti->private;
2269 dm_block_t block = get_bio_block(tc, bio);
2270 struct dm_thin_device *td = tc->td;
2271 struct dm_thin_lookup_result result;
2272 struct dm_bio_prison_cell *virt_cell, *data_cell;
2273 struct dm_cell_key key;
2275 thin_hook_bio(tc, bio);
2277 if (tc->requeue_mode) {
2278 bio_endio(bio, DM_ENDIO_REQUEUE);
2279 return DM_MAPIO_SUBMITTED;
2282 if (get_pool_mode(tc->pool) == PM_FAIL) {
2284 return DM_MAPIO_SUBMITTED;
2287 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
2288 thin_defer_bio_with_throttle(tc, bio);
2289 return DM_MAPIO_SUBMITTED;
2293 * We must hold the virtual cell before doing the lookup, otherwise
2294 * there's a race with discard.
2296 build_virtual_key(tc->td, block, &key);
2297 if (bio_detain(tc->pool, &key, bio, &virt_cell))
2298 return DM_MAPIO_SUBMITTED;
2300 r = dm_thin_find_block(td, block, 0, &result);
2303 * Note that we defer readahead too.
2307 if (unlikely(result.shared)) {
2309 * We have a race condition here between the
2310 * result.shared value returned by the lookup and
2311 * snapshot creation, which may cause new
2314 * To avoid this always quiesce the origin before
2315 * taking the snap. You want to do this anyway to
2316 * ensure a consistent application view
2319 * More distant ancestors are irrelevant. The
2320 * shared flag will be set in their case.
2322 thin_defer_cell(tc, virt_cell);
2323 return DM_MAPIO_SUBMITTED;
2326 build_data_key(tc->td, result.block, &key);
2327 if (bio_detain(tc->pool, &key, bio, &data_cell)) {
2328 cell_defer_no_holder(tc, virt_cell);
2329 return DM_MAPIO_SUBMITTED;
2332 inc_all_io_entry(tc->pool, bio);
2333 cell_defer_no_holder(tc, data_cell);
2334 cell_defer_no_holder(tc, virt_cell);
2336 remap(tc, bio, result.block);
2337 return DM_MAPIO_REMAPPED;
2340 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
2342 * This block isn't provisioned, and we have no way
2345 handle_unserviceable_bio(tc->pool, bio);
2346 cell_defer_no_holder(tc, virt_cell);
2347 return DM_MAPIO_SUBMITTED;
2352 thin_defer_cell(tc, virt_cell);
2353 return DM_MAPIO_SUBMITTED;
2357 * Must always call bio_io_error on failure.
2358 * dm_thin_find_block can fail with -EINVAL if the
2359 * pool is switched to fail-io mode.
2362 cell_defer_no_holder(tc, virt_cell);
2363 return DM_MAPIO_SUBMITTED;
2367 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
2369 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
2370 struct request_queue *q;
2372 if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE)
2375 q = bdev_get_queue(pt->data_dev->bdev);
2376 return bdi_congested(&q->backing_dev_info, bdi_bits);
2379 static void requeue_bios(struct pool *pool)
2381 unsigned long flags;
2385 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
2386 spin_lock_irqsave(&tc->lock, flags);
2387 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
2388 bio_list_init(&tc->retry_on_resume_list);
2389 spin_unlock_irqrestore(&tc->lock, flags);
2394 /*----------------------------------------------------------------
2395 * Binding of control targets to a pool object
2396 *--------------------------------------------------------------*/
2397 static bool data_dev_supports_discard(struct pool_c *pt)
2399 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2401 return q && blk_queue_discard(q);
2404 static bool is_factor(sector_t block_size, uint32_t n)
2406 return !sector_div(block_size, n);
2410 * If discard_passdown was enabled verify that the data device
2411 * supports discards. Disable discard_passdown if not.
2413 static void disable_passdown_if_not_supported(struct pool_c *pt)
2415 struct pool *pool = pt->pool;
2416 struct block_device *data_bdev = pt->data_dev->bdev;
2417 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
2418 sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
2419 const char *reason = NULL;
2420 char buf[BDEVNAME_SIZE];
2422 if (!pt->adjusted_pf.discard_passdown)
2425 if (!data_dev_supports_discard(pt))
2426 reason = "discard unsupported";
2428 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
2429 reason = "max discard sectors smaller than a block";
2431 else if (data_limits->discard_granularity > block_size)
2432 reason = "discard granularity larger than a block";
2434 else if (!is_factor(block_size, data_limits->discard_granularity))
2435 reason = "discard granularity not a factor of block size";
2438 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
2439 pt->adjusted_pf.discard_passdown = false;
2443 static int bind_control_target(struct pool *pool, struct dm_target *ti)
2445 struct pool_c *pt = ti->private;
2448 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2450 enum pool_mode old_mode = get_pool_mode(pool);
2451 enum pool_mode new_mode = pt->adjusted_pf.mode;
2454 * Don't change the pool's mode until set_pool_mode() below.
2455 * Otherwise the pool's process_* function pointers may
2456 * not match the desired pool mode.
2458 pt->adjusted_pf.mode = old_mode;
2461 pool->pf = pt->adjusted_pf;
2462 pool->low_water_blocks = pt->low_water_blocks;
2464 set_pool_mode(pool, new_mode);
2469 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2475 /*----------------------------------------------------------------
2477 *--------------------------------------------------------------*/
2478 /* Initialize pool features. */
2479 static void pool_features_init(struct pool_features *pf)
2481 pf->mode = PM_WRITE;
2482 pf->zero_new_blocks = true;
2483 pf->discard_enabled = true;
2484 pf->discard_passdown = true;
2485 pf->error_if_no_space = false;
2488 static void __pool_destroy(struct pool *pool)
2490 __pool_table_remove(pool);
2492 if (dm_pool_metadata_close(pool->pmd) < 0)
2493 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2495 dm_bio_prison_destroy(pool->prison);
2496 dm_kcopyd_client_destroy(pool->copier);
2499 destroy_workqueue(pool->wq);
2501 if (pool->next_mapping)
2502 mempool_free(pool->next_mapping, pool->mapping_pool);
2503 mempool_destroy(pool->mapping_pool);
2504 dm_deferred_set_destroy(pool->shared_read_ds);
2505 dm_deferred_set_destroy(pool->all_io_ds);
2509 static struct kmem_cache *_new_mapping_cache;
2511 static struct pool *pool_create(struct mapped_device *pool_md,
2512 struct block_device *metadata_dev,
2513 unsigned long block_size,
2514 int read_only, char **error)
2519 struct dm_pool_metadata *pmd;
2520 bool format_device = read_only ? false : true;
2522 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2524 *error = "Error creating metadata object";
2525 return (struct pool *)pmd;
2528 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
2530 *error = "Error allocating memory for pool";
2531 err_p = ERR_PTR(-ENOMEM);
2536 pool->sectors_per_block = block_size;
2537 if (block_size & (block_size - 1))
2538 pool->sectors_per_block_shift = -1;
2540 pool->sectors_per_block_shift = __ffs(block_size);
2541 pool->low_water_blocks = 0;
2542 pool_features_init(&pool->pf);
2543 pool->prison = dm_bio_prison_create();
2544 if (!pool->prison) {
2545 *error = "Error creating pool's bio prison";
2546 err_p = ERR_PTR(-ENOMEM);
2550 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2551 if (IS_ERR(pool->copier)) {
2552 r = PTR_ERR(pool->copier);
2553 *error = "Error creating pool's kcopyd client";
2555 goto bad_kcopyd_client;
2559 * Create singlethreaded workqueue that will service all devices
2560 * that use this metadata.
2562 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2564 *error = "Error creating pool's workqueue";
2565 err_p = ERR_PTR(-ENOMEM);
2569 throttle_init(&pool->throttle);
2570 INIT_WORK(&pool->worker, do_worker);
2571 INIT_DELAYED_WORK(&pool->waker, do_waker);
2572 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
2573 spin_lock_init(&pool->lock);
2574 bio_list_init(&pool->deferred_flush_bios);
2575 INIT_LIST_HEAD(&pool->prepared_mappings);
2576 INIT_LIST_HEAD(&pool->prepared_discards);
2577 INIT_LIST_HEAD(&pool->active_thins);
2578 pool->low_water_triggered = false;
2579 pool->suspended = true;
2581 pool->shared_read_ds = dm_deferred_set_create();
2582 if (!pool->shared_read_ds) {
2583 *error = "Error creating pool's shared read deferred set";
2584 err_p = ERR_PTR(-ENOMEM);
2585 goto bad_shared_read_ds;
2588 pool->all_io_ds = dm_deferred_set_create();
2589 if (!pool->all_io_ds) {
2590 *error = "Error creating pool's all io deferred set";
2591 err_p = ERR_PTR(-ENOMEM);
2595 pool->next_mapping = NULL;
2596 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
2597 _new_mapping_cache);
2598 if (!pool->mapping_pool) {
2599 *error = "Error creating pool's mapping mempool";
2600 err_p = ERR_PTR(-ENOMEM);
2601 goto bad_mapping_pool;
2604 pool->ref_count = 1;
2605 pool->last_commit_jiffies = jiffies;
2606 pool->pool_md = pool_md;
2607 pool->md_dev = metadata_dev;
2608 __pool_table_insert(pool);
2613 dm_deferred_set_destroy(pool->all_io_ds);
2615 dm_deferred_set_destroy(pool->shared_read_ds);
2617 destroy_workqueue(pool->wq);
2619 dm_kcopyd_client_destroy(pool->copier);
2621 dm_bio_prison_destroy(pool->prison);
2625 if (dm_pool_metadata_close(pmd))
2626 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2631 static void __pool_inc(struct pool *pool)
2633 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2637 static void __pool_dec(struct pool *pool)
2639 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2640 BUG_ON(!pool->ref_count);
2641 if (!--pool->ref_count)
2642 __pool_destroy(pool);
2645 static struct pool *__pool_find(struct mapped_device *pool_md,
2646 struct block_device *metadata_dev,
2647 unsigned long block_size, int read_only,
2648 char **error, int *created)
2650 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
2653 if (pool->pool_md != pool_md) {
2654 *error = "metadata device already in use by a pool";
2655 return ERR_PTR(-EBUSY);
2660 pool = __pool_table_lookup(pool_md);
2662 if (pool->md_dev != metadata_dev) {
2663 *error = "different pool cannot replace a pool";
2664 return ERR_PTR(-EINVAL);
2669 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
2677 /*----------------------------------------------------------------
2678 * Pool target methods
2679 *--------------------------------------------------------------*/
2680 static void pool_dtr(struct dm_target *ti)
2682 struct pool_c *pt = ti->private;
2684 mutex_lock(&dm_thin_pool_table.mutex);
2686 unbind_control_target(pt->pool, ti);
2687 __pool_dec(pt->pool);
2688 dm_put_device(ti, pt->metadata_dev);
2689 dm_put_device(ti, pt->data_dev);
2692 mutex_unlock(&dm_thin_pool_table.mutex);
2695 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
2696 struct dm_target *ti)
2700 const char *arg_name;
2702 static struct dm_arg _args[] = {
2703 {0, 4, "Invalid number of pool feature arguments"},
2707 * No feature arguments supplied.
2712 r = dm_read_arg_group(_args, as, &argc, &ti->error);
2716 while (argc && !r) {
2717 arg_name = dm_shift_arg(as);
2720 if (!strcasecmp(arg_name, "skip_block_zeroing"))
2721 pf->zero_new_blocks = false;
2723 else if (!strcasecmp(arg_name, "ignore_discard"))
2724 pf->discard_enabled = false;
2726 else if (!strcasecmp(arg_name, "no_discard_passdown"))
2727 pf->discard_passdown = false;
2729 else if (!strcasecmp(arg_name, "read_only"))
2730 pf->mode = PM_READ_ONLY;
2732 else if (!strcasecmp(arg_name, "error_if_no_space"))
2733 pf->error_if_no_space = true;
2736 ti->error = "Unrecognised pool feature requested";
2745 static void metadata_low_callback(void *context)
2747 struct pool *pool = context;
2749 DMWARN("%s: reached low water mark for metadata device: sending event.",
2750 dm_device_name(pool->pool_md));
2752 dm_table_event(pool->ti->table);
2755 static sector_t get_dev_size(struct block_device *bdev)
2757 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
2760 static void warn_if_metadata_device_too_big(struct block_device *bdev)
2762 sector_t metadata_dev_size = get_dev_size(bdev);
2763 char buffer[BDEVNAME_SIZE];
2765 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
2766 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
2767 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
2770 static sector_t get_metadata_dev_size(struct block_device *bdev)
2772 sector_t metadata_dev_size = get_dev_size(bdev);
2774 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
2775 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
2777 return metadata_dev_size;
2780 static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
2782 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
2784 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
2786 return metadata_dev_size;
2790 * When a metadata threshold is crossed a dm event is triggered, and
2791 * userland should respond by growing the metadata device. We could let
2792 * userland set the threshold, like we do with the data threshold, but I'm
2793 * not sure they know enough to do this well.
2795 static dm_block_t calc_metadata_threshold(struct pool_c *pt)
2798 * 4M is ample for all ops with the possible exception of thin
2799 * device deletion which is harmless if it fails (just retry the
2800 * delete after you've grown the device).
2802 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
2803 return min((dm_block_t)1024ULL /* 4M */, quarter);
2807 * thin-pool <metadata dev> <data dev>
2808 * <data block size (sectors)>
2809 * <low water mark (blocks)>
2810 * [<#feature args> [<arg>]*]
2812 * Optional feature arguments are:
2813 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
2814 * ignore_discard: disable discard
2815 * no_discard_passdown: don't pass discards down to the data device
2816 * read_only: Don't allow any changes to be made to the pool metadata.
2817 * error_if_no_space: error IOs, instead of queueing, if no space.
2819 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
2821 int r, pool_created = 0;
2824 struct pool_features pf;
2825 struct dm_arg_set as;
2826 struct dm_dev *data_dev;
2827 unsigned long block_size;
2828 dm_block_t low_water_blocks;
2829 struct dm_dev *metadata_dev;
2830 fmode_t metadata_mode;
2833 * FIXME Remove validation from scope of lock.
2835 mutex_lock(&dm_thin_pool_table.mutex);
2838 ti->error = "Invalid argument count";
2847 * Set default pool features.
2849 pool_features_init(&pf);
2851 dm_consume_args(&as, 4);
2852 r = parse_pool_features(&as, &pf, ti);
2856 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
2857 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
2859 ti->error = "Error opening metadata block device";
2862 warn_if_metadata_device_too_big(metadata_dev->bdev);
2864 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
2866 ti->error = "Error getting data device";
2870 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
2871 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
2872 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
2873 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
2874 ti->error = "Invalid block size";
2879 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
2880 ti->error = "Invalid low water mark";
2885 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
2891 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
2892 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
2899 * 'pool_created' reflects whether this is the first table load.
2900 * Top level discard support is not allowed to be changed after
2901 * initial load. This would require a pool reload to trigger thin
2904 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
2905 ti->error = "Discard support cannot be disabled once enabled";
2907 goto out_flags_changed;
2912 pt->metadata_dev = metadata_dev;
2913 pt->data_dev = data_dev;
2914 pt->low_water_blocks = low_water_blocks;
2915 pt->adjusted_pf = pt->requested_pf = pf;
2916 ti->num_flush_bios = 1;
2919 * Only need to enable discards if the pool should pass
2920 * them down to the data device. The thin device's discard
2921 * processing will cause mappings to be removed from the btree.
2923 ti->discard_zeroes_data_unsupported = true;
2924 if (pf.discard_enabled && pf.discard_passdown) {
2925 ti->num_discard_bios = 1;
2928 * Setting 'discards_supported' circumvents the normal
2929 * stacking of discard limits (this keeps the pool and
2930 * thin devices' discard limits consistent).
2932 ti->discards_supported = true;
2936 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
2937 calc_metadata_threshold(pt),
2938 metadata_low_callback,
2943 pt->callbacks.congested_fn = pool_is_congested;
2944 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2946 mutex_unlock(&dm_thin_pool_table.mutex);
2955 dm_put_device(ti, data_dev);
2957 dm_put_device(ti, metadata_dev);
2959 mutex_unlock(&dm_thin_pool_table.mutex);
2964 static int pool_map(struct dm_target *ti, struct bio *bio)
2967 struct pool_c *pt = ti->private;
2968 struct pool *pool = pt->pool;
2969 unsigned long flags;
2972 * As this is a singleton target, ti->begin is always zero.
2974 spin_lock_irqsave(&pool->lock, flags);
2975 bio->bi_bdev = pt->data_dev->bdev;
2976 r = DM_MAPIO_REMAPPED;
2977 spin_unlock_irqrestore(&pool->lock, flags);
2982 static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
2985 struct pool_c *pt = ti->private;
2986 struct pool *pool = pt->pool;
2987 sector_t data_size = ti->len;
2988 dm_block_t sb_data_size;
2990 *need_commit = false;
2992 (void) sector_div(data_size, pool->sectors_per_block);
2994 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2996 DMERR("%s: failed to retrieve data device size",
2997 dm_device_name(pool->pool_md));
3001 if (data_size < sb_data_size) {
3002 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
3003 dm_device_name(pool->pool_md),
3004 (unsigned long long)data_size, sb_data_size);
3007 } else if (data_size > sb_data_size) {
3008 if (dm_pool_metadata_needs_check(pool->pmd)) {
3009 DMERR("%s: unable to grow the data device until repaired.",
3010 dm_device_name(pool->pool_md));
3015 DMINFO("%s: growing the data device from %llu to %llu blocks",
3016 dm_device_name(pool->pool_md),
3017 sb_data_size, (unsigned long long)data_size);
3018 r = dm_pool_resize_data_dev(pool->pmd, data_size);
3020 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
3024 *need_commit = true;
3030 static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
3033 struct pool_c *pt = ti->private;
3034 struct pool *pool = pt->pool;
3035 dm_block_t metadata_dev_size, sb_metadata_dev_size;
3037 *need_commit = false;
3039 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
3041 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
3043 DMERR("%s: failed to retrieve metadata device size",
3044 dm_device_name(pool->pool_md));
3048 if (metadata_dev_size < sb_metadata_dev_size) {
3049 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
3050 dm_device_name(pool->pool_md),
3051 metadata_dev_size, sb_metadata_dev_size);
3054 } else if (metadata_dev_size > sb_metadata_dev_size) {
3055 if (dm_pool_metadata_needs_check(pool->pmd)) {
3056 DMERR("%s: unable to grow the metadata device until repaired.",
3057 dm_device_name(pool->pool_md));
3061 warn_if_metadata_device_too_big(pool->md_dev);
3062 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
3063 dm_device_name(pool->pool_md),
3064 sb_metadata_dev_size, metadata_dev_size);
3065 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
3067 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
3071 *need_commit = true;
3078 * Retrieves the number of blocks of the data device from
3079 * the superblock and compares it to the actual device size,
3080 * thus resizing the data device in case it has grown.
3082 * This both copes with opening preallocated data devices in the ctr
3083 * being followed by a resume
3085 * calling the resume method individually after userspace has
3086 * grown the data device in reaction to a table event.
3088 static int pool_preresume(struct dm_target *ti)
3091 bool need_commit1, need_commit2;
3092 struct pool_c *pt = ti->private;
3093 struct pool *pool = pt->pool;
3096 * Take control of the pool object.
3098 r = bind_control_target(pool, ti);
3102 r = maybe_resize_data_dev(ti, &need_commit1);
3106 r = maybe_resize_metadata_dev(ti, &need_commit2);
3110 if (need_commit1 || need_commit2)
3111 (void) commit(pool);
3116 static void pool_resume(struct dm_target *ti)
3118 struct pool_c *pt = ti->private;
3119 struct pool *pool = pt->pool;
3120 unsigned long flags;
3122 spin_lock_irqsave(&pool->lock, flags);
3123 pool->low_water_triggered = false;
3124 pool->suspended = false;
3125 spin_unlock_irqrestore(&pool->lock, flags);
3129 do_waker(&pool->waker.work);
3132 static void pool_presuspend(struct dm_target *ti)
3134 struct pool_c *pt = ti->private;
3135 struct pool *pool = pt->pool;
3136 unsigned long flags;
3138 spin_lock_irqsave(&pool->lock, flags);
3139 pool->suspended = true;
3140 spin_unlock_irqrestore(&pool->lock, flags);
3143 static void pool_presuspend_undo(struct dm_target *ti)
3145 struct pool_c *pt = ti->private;
3146 struct pool *pool = pt->pool;
3147 unsigned long flags;
3149 spin_lock_irqsave(&pool->lock, flags);
3150 pool->suspended = false;
3151 spin_unlock_irqrestore(&pool->lock, flags);
3154 static void pool_postsuspend(struct dm_target *ti)
3156 struct pool_c *pt = ti->private;
3157 struct pool *pool = pt->pool;
3159 cancel_delayed_work(&pool->waker);
3160 cancel_delayed_work(&pool->no_space_timeout);
3161 flush_workqueue(pool->wq);
3162 (void) commit(pool);
3165 static int check_arg_count(unsigned argc, unsigned args_required)
3167 if (argc != args_required) {
3168 DMWARN("Message received with %u arguments instead of %u.",
3169 argc, args_required);
3176 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
3178 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
3179 *dev_id <= MAX_DEV_ID)
3183 DMWARN("Message received with invalid device id: %s", arg);
3188 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
3193 r = check_arg_count(argc, 2);
3197 r = read_dev_id(argv[1], &dev_id, 1);
3201 r = dm_pool_create_thin(pool->pmd, dev_id);
3203 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
3211 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3214 dm_thin_id origin_dev_id;
3217 r = check_arg_count(argc, 3);
3221 r = read_dev_id(argv[1], &dev_id, 1);
3225 r = read_dev_id(argv[2], &origin_dev_id, 1);
3229 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
3231 DMWARN("Creation of new snapshot %s of device %s failed.",
3239 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
3244 r = check_arg_count(argc, 2);
3248 r = read_dev_id(argv[1], &dev_id, 1);
3252 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
3254 DMWARN("Deletion of thin device %s failed.", argv[1]);
3259 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
3261 dm_thin_id old_id, new_id;
3264 r = check_arg_count(argc, 3);
3268 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
3269 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
3273 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
3274 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
3278 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
3280 DMWARN("Failed to change transaction id from %s to %s.",
3288 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3292 r = check_arg_count(argc, 1);
3296 (void) commit(pool);
3298 r = dm_pool_reserve_metadata_snap(pool->pmd);
3300 DMWARN("reserve_metadata_snap message failed.");
3305 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3309 r = check_arg_count(argc, 1);
3313 r = dm_pool_release_metadata_snap(pool->pmd);
3315 DMWARN("release_metadata_snap message failed.");
3321 * Messages supported:
3322 * create_thin <dev_id>
3323 * create_snap <dev_id> <origin_id>
3325 * set_transaction_id <current_trans_id> <new_trans_id>
3326 * reserve_metadata_snap
3327 * release_metadata_snap
3329 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
3332 struct pool_c *pt = ti->private;
3333 struct pool *pool = pt->pool;
3335 if (!strcasecmp(argv[0], "create_thin"))
3336 r = process_create_thin_mesg(argc, argv, pool);
3338 else if (!strcasecmp(argv[0], "create_snap"))
3339 r = process_create_snap_mesg(argc, argv, pool);
3341 else if (!strcasecmp(argv[0], "delete"))
3342 r = process_delete_mesg(argc, argv, pool);
3344 else if (!strcasecmp(argv[0], "set_transaction_id"))
3345 r = process_set_transaction_id_mesg(argc, argv, pool);
3347 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
3348 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
3350 else if (!strcasecmp(argv[0], "release_metadata_snap"))
3351 r = process_release_metadata_snap_mesg(argc, argv, pool);
3354 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
3357 (void) commit(pool);
3362 static void emit_flags(struct pool_features *pf, char *result,
3363 unsigned sz, unsigned maxlen)
3365 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
3366 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
3367 pf->error_if_no_space;
3368 DMEMIT("%u ", count);
3370 if (!pf->zero_new_blocks)
3371 DMEMIT("skip_block_zeroing ");
3373 if (!pf->discard_enabled)
3374 DMEMIT("ignore_discard ");
3376 if (!pf->discard_passdown)
3377 DMEMIT("no_discard_passdown ");
3379 if (pf->mode == PM_READ_ONLY)
3380 DMEMIT("read_only ");
3382 if (pf->error_if_no_space)
3383 DMEMIT("error_if_no_space ");
3388 * <transaction id> <used metadata sectors>/<total metadata sectors>
3389 * <used data sectors>/<total data sectors> <held metadata root>
3391 static void pool_status(struct dm_target *ti, status_type_t type,
3392 unsigned status_flags, char *result, unsigned maxlen)
3396 uint64_t transaction_id;
3397 dm_block_t nr_free_blocks_data;
3398 dm_block_t nr_free_blocks_metadata;
3399 dm_block_t nr_blocks_data;
3400 dm_block_t nr_blocks_metadata;
3401 dm_block_t held_root;
3402 char buf[BDEVNAME_SIZE];
3403 char buf2[BDEVNAME_SIZE];
3404 struct pool_c *pt = ti->private;
3405 struct pool *pool = pt->pool;
3408 case STATUSTYPE_INFO:
3409 if (get_pool_mode(pool) == PM_FAIL) {
3414 /* Commit to ensure statistics aren't out-of-date */
3415 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3416 (void) commit(pool);
3418 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
3420 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
3421 dm_device_name(pool->pool_md), r);
3425 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
3427 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
3428 dm_device_name(pool->pool_md), r);
3432 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
3434 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
3435 dm_device_name(pool->pool_md), r);
3439 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
3441 DMERR("%s: dm_pool_get_free_block_count returned %d",
3442 dm_device_name(pool->pool_md), r);
3446 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
3448 DMERR("%s: dm_pool_get_data_dev_size returned %d",
3449 dm_device_name(pool->pool_md), r);
3453 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
3455 DMERR("%s: dm_pool_get_metadata_snap returned %d",
3456 dm_device_name(pool->pool_md), r);
3460 DMEMIT("%llu %llu/%llu %llu/%llu ",
3461 (unsigned long long)transaction_id,
3462 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3463 (unsigned long long)nr_blocks_metadata,
3464 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
3465 (unsigned long long)nr_blocks_data);
3468 DMEMIT("%llu ", held_root);
3472 if (pool->pf.mode == PM_OUT_OF_DATA_SPACE)
3473 DMEMIT("out_of_data_space ");
3474 else if (pool->pf.mode == PM_READ_ONLY)
3479 if (!pool->pf.discard_enabled)
3480 DMEMIT("ignore_discard ");
3481 else if (pool->pf.discard_passdown)
3482 DMEMIT("discard_passdown ");
3484 DMEMIT("no_discard_passdown ");
3486 if (pool->pf.error_if_no_space)
3487 DMEMIT("error_if_no_space ");
3489 DMEMIT("queue_if_no_space ");
3493 case STATUSTYPE_TABLE:
3494 DMEMIT("%s %s %lu %llu ",
3495 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
3496 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
3497 (unsigned long)pool->sectors_per_block,
3498 (unsigned long long)pt->low_water_blocks);
3499 emit_flags(&pt->requested_pf, result, sz, maxlen);
3508 static int pool_iterate_devices(struct dm_target *ti,
3509 iterate_devices_callout_fn fn, void *data)
3511 struct pool_c *pt = ti->private;
3513 return fn(ti, pt->data_dev, 0, ti->len, data);
3516 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
3517 struct bio_vec *biovec, int max_size)
3519 struct pool_c *pt = ti->private;
3520 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
3522 if (!q->merge_bvec_fn)
3525 bvm->bi_bdev = pt->data_dev->bdev;
3527 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3530 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
3532 struct pool *pool = pt->pool;
3533 struct queue_limits *data_limits;
3535 limits->max_discard_sectors = pool->sectors_per_block;
3538 * discard_granularity is just a hint, and not enforced.
3540 if (pt->adjusted_pf.discard_passdown) {
3541 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
3542 limits->discard_granularity = max(data_limits->discard_granularity,
3543 pool->sectors_per_block << SECTOR_SHIFT);
3545 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
3548 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
3550 struct pool_c *pt = ti->private;
3551 struct pool *pool = pt->pool;
3552 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
3555 * Adjust max_sectors_kb to highest possible power-of-2
3556 * factor of pool->sectors_per_block.
3558 if (limits->max_hw_sectors & (limits->max_hw_sectors - 1))
3559 limits->max_sectors = rounddown_pow_of_two(limits->max_hw_sectors);
3561 limits->max_sectors = limits->max_hw_sectors;
3563 if (limits->max_sectors < pool->sectors_per_block) {
3564 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
3565 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
3566 limits->max_sectors--;
3567 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
3569 } else if (block_size_is_power_of_two(pool)) {
3570 /* max_sectors_kb is >= power-of-2 thinp blocksize */
3571 while (!is_factor(limits->max_sectors, pool->sectors_per_block)) {
3572 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
3573 limits->max_sectors--;
3574 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
3579 * If the system-determined stacked limits are compatible with the
3580 * pool's blocksize (io_opt is a factor) do not override them.
3582 if (io_opt_sectors < pool->sectors_per_block ||
3583 !is_factor(io_opt_sectors, pool->sectors_per_block)) {
3584 if (is_factor(pool->sectors_per_block, limits->max_sectors))
3585 blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT);
3587 blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);
3588 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
3592 * pt->adjusted_pf is a staging area for the actual features to use.
3593 * They get transferred to the live pool in bind_control_target()
3594 * called from pool_preresume().
3596 if (!pt->adjusted_pf.discard_enabled) {
3598 * Must explicitly disallow stacking discard limits otherwise the
3599 * block layer will stack them if pool's data device has support.
3600 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
3601 * user to see that, so make sure to set all discard limits to 0.
3603 limits->discard_granularity = 0;
3607 disable_passdown_if_not_supported(pt);
3609 set_discard_limits(pt, limits);
3612 static struct target_type pool_target = {
3613 .name = "thin-pool",
3614 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
3615 DM_TARGET_IMMUTABLE,
3616 .version = {1, 14, 0},
3617 .module = THIS_MODULE,
3621 .presuspend = pool_presuspend,
3622 .presuspend_undo = pool_presuspend_undo,
3623 .postsuspend = pool_postsuspend,
3624 .preresume = pool_preresume,
3625 .resume = pool_resume,
3626 .message = pool_message,
3627 .status = pool_status,
3628 .merge = pool_merge,
3629 .iterate_devices = pool_iterate_devices,
3630 .io_hints = pool_io_hints,
3633 /*----------------------------------------------------------------
3634 * Thin target methods
3635 *--------------------------------------------------------------*/
3636 static void thin_get(struct thin_c *tc)
3638 atomic_inc(&tc->refcount);
3641 static void thin_put(struct thin_c *tc)
3643 if (atomic_dec_and_test(&tc->refcount))
3644 complete(&tc->can_destroy);
3647 static void thin_dtr(struct dm_target *ti)
3649 struct thin_c *tc = ti->private;
3650 unsigned long flags;
3652 spin_lock_irqsave(&tc->pool->lock, flags);
3653 list_del_rcu(&tc->list);
3654 spin_unlock_irqrestore(&tc->pool->lock, flags);
3658 wait_for_completion(&tc->can_destroy);
3660 mutex_lock(&dm_thin_pool_table.mutex);
3662 __pool_dec(tc->pool);
3663 dm_pool_close_thin_device(tc->td);
3664 dm_put_device(ti, tc->pool_dev);
3666 dm_put_device(ti, tc->origin_dev);
3669 mutex_unlock(&dm_thin_pool_table.mutex);
3673 * Thin target parameters:
3675 * <pool_dev> <dev_id> [origin_dev]
3677 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
3678 * dev_id: the internal device identifier
3679 * origin_dev: a device external to the pool that should act as the origin
3681 * If the pool device has discards disabled, they get disabled for the thin
3684 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
3688 struct dm_dev *pool_dev, *origin_dev;
3689 struct mapped_device *pool_md;
3690 unsigned long flags;
3692 mutex_lock(&dm_thin_pool_table.mutex);
3694 if (argc != 2 && argc != 3) {
3695 ti->error = "Invalid argument count";
3700 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
3702 ti->error = "Out of memory";
3706 spin_lock_init(&tc->lock);
3707 INIT_LIST_HEAD(&tc->deferred_cells);
3708 bio_list_init(&tc->deferred_bio_list);
3709 bio_list_init(&tc->retry_on_resume_list);
3710 tc->sort_bio_list = RB_ROOT;
3713 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
3715 ti->error = "Error opening origin device";
3716 goto bad_origin_dev;
3718 tc->origin_dev = origin_dev;
3721 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
3723 ti->error = "Error opening pool device";
3726 tc->pool_dev = pool_dev;
3728 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
3729 ti->error = "Invalid device id";
3734 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
3736 ti->error = "Couldn't get pool mapped device";
3741 tc->pool = __pool_table_lookup(pool_md);
3743 ti->error = "Couldn't find pool object";
3745 goto bad_pool_lookup;
3747 __pool_inc(tc->pool);
3749 if (get_pool_mode(tc->pool) == PM_FAIL) {
3750 ti->error = "Couldn't open thin device, Pool is in fail mode";
3755 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
3757 ti->error = "Couldn't open thin internal device";
3761 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
3765 ti->num_flush_bios = 1;
3766 ti->flush_supported = true;
3767 ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
3769 /* In case the pool supports discards, pass them on. */
3770 ti->discard_zeroes_data_unsupported = true;
3771 if (tc->pool->pf.discard_enabled) {
3772 ti->discards_supported = true;
3773 ti->num_discard_bios = 1;
3774 /* Discard bios must be split on a block boundary */
3775 ti->split_discard_bios = true;
3778 mutex_unlock(&dm_thin_pool_table.mutex);
3780 spin_lock_irqsave(&tc->pool->lock, flags);
3781 if (tc->pool->suspended) {
3782 spin_unlock_irqrestore(&tc->pool->lock, flags);
3783 mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */
3784 ti->error = "Unable to activate thin device while pool is suspended";
3788 list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
3789 spin_unlock_irqrestore(&tc->pool->lock, flags);
3791 * This synchronize_rcu() call is needed here otherwise we risk a
3792 * wake_worker() call finding no bios to process (because the newly
3793 * added tc isn't yet visible). So this reduces latency since we
3794 * aren't then dependent on the periodic commit to wake_worker().
3800 atomic_set(&tc->refcount, 1);
3801 init_completion(&tc->can_destroy);
3806 dm_pool_close_thin_device(tc->td);
3808 __pool_dec(tc->pool);
3812 dm_put_device(ti, tc->pool_dev);
3815 dm_put_device(ti, tc->origin_dev);
3819 mutex_unlock(&dm_thin_pool_table.mutex);
3824 static int thin_map(struct dm_target *ti, struct bio *bio)
3826 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
3828 return thin_bio_map(ti, bio);
3831 static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
3833 unsigned long flags;
3834 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
3835 struct list_head work;
3836 struct dm_thin_new_mapping *m, *tmp;
3837 struct pool *pool = h->tc->pool;
3839 if (h->shared_read_entry) {
3840 INIT_LIST_HEAD(&work);
3841 dm_deferred_entry_dec(h->shared_read_entry, &work);
3843 spin_lock_irqsave(&pool->lock, flags);
3844 list_for_each_entry_safe(m, tmp, &work, list) {
3846 __complete_mapping_preparation(m);
3848 spin_unlock_irqrestore(&pool->lock, flags);
3851 if (h->all_io_entry) {
3852 INIT_LIST_HEAD(&work);
3853 dm_deferred_entry_dec(h->all_io_entry, &work);
3854 if (!list_empty(&work)) {
3855 spin_lock_irqsave(&pool->lock, flags);
3856 list_for_each_entry_safe(m, tmp, &work, list)
3857 list_add_tail(&m->list, &pool->prepared_discards);
3858 spin_unlock_irqrestore(&pool->lock, flags);
3866 static void thin_presuspend(struct dm_target *ti)
3868 struct thin_c *tc = ti->private;
3870 if (dm_noflush_suspending(ti))
3871 noflush_work(tc, do_noflush_start);
3874 static void thin_postsuspend(struct dm_target *ti)
3876 struct thin_c *tc = ti->private;
3879 * The dm_noflush_suspending flag has been cleared by now, so
3880 * unfortunately we must always run this.
3882 noflush_work(tc, do_noflush_stop);
3885 static int thin_preresume(struct dm_target *ti)
3887 struct thin_c *tc = ti->private;
3890 tc->origin_size = get_dev_size(tc->origin_dev->bdev);
3896 * <nr mapped sectors> <highest mapped sector>
3898 static void thin_status(struct dm_target *ti, status_type_t type,
3899 unsigned status_flags, char *result, unsigned maxlen)
3903 dm_block_t mapped, highest;
3904 char buf[BDEVNAME_SIZE];
3905 struct thin_c *tc = ti->private;
3907 if (get_pool_mode(tc->pool) == PM_FAIL) {
3916 case STATUSTYPE_INFO:
3917 r = dm_thin_get_mapped_count(tc->td, &mapped);
3919 DMERR("dm_thin_get_mapped_count returned %d", r);
3923 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
3925 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
3929 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
3931 DMEMIT("%llu", ((highest + 1) *
3932 tc->pool->sectors_per_block) - 1);
3937 case STATUSTYPE_TABLE:
3939 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
3940 (unsigned long) tc->dev_id);
3942 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
3953 static int thin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
3954 struct bio_vec *biovec, int max_size)
3956 struct thin_c *tc = ti->private;
3957 struct request_queue *q = bdev_get_queue(tc->pool_dev->bdev);
3959 if (!q->merge_bvec_fn)
3962 bvm->bi_bdev = tc->pool_dev->bdev;
3963 bvm->bi_sector = dm_target_offset(ti, bvm->bi_sector);
3965 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3968 static int thin_iterate_devices(struct dm_target *ti,
3969 iterate_devices_callout_fn fn, void *data)
3972 struct thin_c *tc = ti->private;
3973 struct pool *pool = tc->pool;
3976 * We can't call dm_pool_get_data_dev_size() since that blocks. So
3977 * we follow a more convoluted path through to the pool's target.
3980 return 0; /* nothing is bound */
3982 blocks = pool->ti->len;
3983 (void) sector_div(blocks, pool->sectors_per_block);
3985 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
3990 static struct target_type thin_target = {
3992 .version = {1, 14, 0},
3993 .module = THIS_MODULE,
3997 .end_io = thin_endio,
3998 .preresume = thin_preresume,
3999 .presuspend = thin_presuspend,
4000 .postsuspend = thin_postsuspend,
4001 .status = thin_status,
4002 .merge = thin_merge,
4003 .iterate_devices = thin_iterate_devices,
4006 /*----------------------------------------------------------------*/
4008 static int __init dm_thin_init(void)
4014 r = dm_register_target(&thin_target);
4018 r = dm_register_target(&pool_target);
4020 goto bad_pool_target;
4024 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
4025 if (!_new_mapping_cache)
4026 goto bad_new_mapping_cache;
4030 bad_new_mapping_cache:
4031 dm_unregister_target(&pool_target);
4033 dm_unregister_target(&thin_target);
4038 static void dm_thin_exit(void)
4040 dm_unregister_target(&thin_target);
4041 dm_unregister_target(&pool_target);
4043 kmem_cache_destroy(_new_mapping_cache);
4046 module_init(dm_thin_init);
4047 module_exit(dm_thin_exit);
4049 module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);
4050 MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
4052 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
4053 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
4054 MODULE_LICENSE("GPL");