2 * Copyright (C) 2011-2012 Red Hat UK.
4 * This file is released under the GPL.
7 #include "dm-thin-metadata.h"
8 #include "dm-bio-prison.h"
11 #include <linux/device-mapper.h>
12 #include <linux/dm-io.h>
13 #include <linux/dm-kcopyd.h>
14 #include <linux/log2.h>
15 #include <linux/list.h>
16 #include <linux/rculist.h>
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
20 #include <linux/rbtree.h>
22 #define DM_MSG_PREFIX "thin"
27 #define ENDIO_HOOK_POOL_SIZE 1024
28 #define MAPPING_POOL_SIZE 1024
29 #define COMMIT_PERIOD HZ
30 #define NO_SPACE_TIMEOUT_SECS 60
32 static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
34 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
35 "A percentage of time allocated for copy on write");
38 * The block size of the device holding pool data must be
39 * between 64KB and 1GB.
41 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
42 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
45 * Device id is restricted to 24 bits.
47 #define MAX_DEV_ID ((1 << 24) - 1)
50 * How do we handle breaking sharing of data blocks?
51 * =================================================
53 * We use a standard copy-on-write btree to store the mappings for the
54 * devices (note I'm talking about copy-on-write of the metadata here, not
55 * the data). When you take an internal snapshot you clone the root node
56 * of the origin btree. After this there is no concept of an origin or a
57 * snapshot. They are just two device trees that happen to point to the
60 * When we get a write in we decide if it's to a shared data block using
61 * some timestamp magic. If it is, we have to break sharing.
63 * Let's say we write to a shared block in what was the origin. The
66 * i) plug io further to this physical block. (see bio_prison code).
68 * ii) quiesce any read io to that shared data block. Obviously
69 * including all devices that share this block. (see dm_deferred_set code)
71 * iii) copy the data block to a newly allocate block. This step can be
72 * missed out if the io covers the block. (schedule_copy).
74 * iv) insert the new mapping into the origin's btree
75 * (process_prepared_mapping). This act of inserting breaks some
76 * sharing of btree nodes between the two devices. Breaking sharing only
77 * effects the btree of that specific device. Btrees for the other
78 * devices that share the block never change. The btree for the origin
79 * device as it was after the last commit is untouched, ie. we're using
80 * persistent data structures in the functional programming sense.
82 * v) unplug io to this physical block, including the io that triggered
83 * the breaking of sharing.
85 * Steps (ii) and (iii) occur in parallel.
87 * The metadata _doesn't_ need to be committed before the io continues. We
88 * get away with this because the io is always written to a _new_ block.
89 * If there's a crash, then:
91 * - The origin mapping will point to the old origin block (the shared
92 * one). This will contain the data as it was before the io that triggered
93 * the breaking of sharing came in.
95 * - The snap mapping still points to the old block. As it would after
98 * The downside of this scheme is the timestamp magic isn't perfect, and
99 * will continue to think that data block in the snapshot device is shared
100 * even after the write to the origin has broken sharing. I suspect data
101 * blocks will typically be shared by many different devices, so we're
102 * breaking sharing n + 1 times, rather than n, where n is the number of
103 * devices that reference this data block. At the moment I think the
104 * benefits far, far outweigh the disadvantages.
107 /*----------------------------------------------------------------*/
112 static void build_data_key(struct dm_thin_device *td,
113 dm_block_t b, struct dm_cell_key *key)
116 key->dev = dm_thin_dev_id(td);
120 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
121 struct dm_cell_key *key)
124 key->dev = dm_thin_dev_id(td);
128 /*----------------------------------------------------------------*/
130 #define THROTTLE_THRESHOLD (1 * HZ)
133 struct rw_semaphore lock;
134 unsigned long threshold;
135 bool throttle_applied;
138 static void throttle_init(struct throttle *t)
140 init_rwsem(&t->lock);
141 t->throttle_applied = false;
144 static void throttle_work_start(struct throttle *t)
146 t->threshold = jiffies + THROTTLE_THRESHOLD;
149 static void throttle_work_update(struct throttle *t)
151 if (!t->throttle_applied && jiffies > t->threshold) {
152 down_write(&t->lock);
153 t->throttle_applied = true;
157 static void throttle_work_complete(struct throttle *t)
159 if (t->throttle_applied) {
160 t->throttle_applied = false;
165 static void throttle_lock(struct throttle *t)
170 static void throttle_unlock(struct throttle *t)
175 /*----------------------------------------------------------------*/
178 * A pool device ties together a metadata device and a data device. It
179 * also provides the interface for creating and destroying internal
182 struct dm_thin_new_mapping;
185 * The pool runs in 4 modes. Ordered in degraded order for comparisons.
188 PM_WRITE, /* metadata may be changed */
189 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
190 PM_READ_ONLY, /* metadata may not be changed */
191 PM_FAIL, /* all I/O fails */
194 struct pool_features {
197 bool zero_new_blocks:1;
198 bool discard_enabled:1;
199 bool discard_passdown:1;
200 bool error_if_no_space:1;
204 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
205 typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell);
206 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
209 struct list_head list;
210 struct dm_target *ti; /* Only set if a pool target is bound */
212 struct mapped_device *pool_md;
213 struct block_device *md_dev;
214 struct dm_pool_metadata *pmd;
216 dm_block_t low_water_blocks;
217 uint32_t sectors_per_block;
218 int sectors_per_block_shift;
220 struct pool_features pf;
221 bool low_water_triggered:1; /* A dm event has been sent */
223 struct dm_bio_prison *prison;
224 struct dm_kcopyd_client *copier;
226 struct workqueue_struct *wq;
227 struct throttle throttle;
228 struct work_struct worker;
229 struct delayed_work waker;
230 struct delayed_work no_space_timeout;
232 unsigned long last_commit_jiffies;
236 struct bio_list deferred_flush_bios;
237 struct list_head prepared_mappings;
238 struct list_head prepared_discards;
239 struct list_head active_thins;
241 struct dm_deferred_set *shared_read_ds;
242 struct dm_deferred_set *all_io_ds;
244 struct dm_thin_new_mapping *next_mapping;
245 mempool_t *mapping_pool;
247 process_bio_fn process_bio;
248 process_bio_fn process_discard;
250 process_cell_fn process_cell;
251 process_cell_fn process_discard_cell;
253 process_mapping_fn process_prepared_mapping;
254 process_mapping_fn process_prepared_discard;
257 static enum pool_mode get_pool_mode(struct pool *pool);
258 static void metadata_operation_failed(struct pool *pool, const char *op, int r);
261 * Target context for a pool.
264 struct dm_target *ti;
266 struct dm_dev *data_dev;
267 struct dm_dev *metadata_dev;
268 struct dm_target_callbacks callbacks;
270 dm_block_t low_water_blocks;
271 struct pool_features requested_pf; /* Features requested during table load */
272 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
276 * Target context for a thin.
279 struct list_head list;
280 struct dm_dev *pool_dev;
281 struct dm_dev *origin_dev;
282 sector_t origin_size;
286 struct dm_thin_device *td;
289 struct list_head deferred_cells;
290 struct bio_list deferred_bio_list;
291 struct bio_list retry_on_resume_list;
292 struct rb_root sort_bio_list; /* sorted list of deferred bios */
295 * Ensures the thin is not destroyed until the worker has finished
296 * iterating the active_thins list.
299 struct completion can_destroy;
302 /*----------------------------------------------------------------*/
305 * wake_worker() is used when new work is queued and when pool_resume is
306 * ready to continue deferred IO processing.
308 static void wake_worker(struct pool *pool)
310 queue_work(pool->wq, &pool->worker);
313 /*----------------------------------------------------------------*/
315 static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
316 struct dm_bio_prison_cell **cell_result)
319 struct dm_bio_prison_cell *cell_prealloc;
322 * Allocate a cell from the prison's mempool.
323 * This might block but it can't fail.
325 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
327 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
330 * We reused an old cell; we can get rid of
333 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
338 static void cell_release(struct pool *pool,
339 struct dm_bio_prison_cell *cell,
340 struct bio_list *bios)
342 dm_cell_release(pool->prison, cell, bios);
343 dm_bio_prison_free_cell(pool->prison, cell);
346 static void cell_visit_release(struct pool *pool,
347 void (*fn)(void *, struct dm_bio_prison_cell *),
349 struct dm_bio_prison_cell *cell)
351 dm_cell_visit_release(pool->prison, fn, context, cell);
352 dm_bio_prison_free_cell(pool->prison, cell);
355 static void cell_release_no_holder(struct pool *pool,
356 struct dm_bio_prison_cell *cell,
357 struct bio_list *bios)
359 dm_cell_release_no_holder(pool->prison, cell, bios);
360 dm_bio_prison_free_cell(pool->prison, cell);
363 static void cell_error_with_code(struct pool *pool,
364 struct dm_bio_prison_cell *cell, int error_code)
366 dm_cell_error(pool->prison, cell, error_code);
367 dm_bio_prison_free_cell(pool->prison, cell);
370 static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
372 cell_error_with_code(pool, cell, -EIO);
375 static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
377 cell_error_with_code(pool, cell, 0);
380 static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
382 cell_error_with_code(pool, cell, DM_ENDIO_REQUEUE);
385 /*----------------------------------------------------------------*/
388 * A global list of pools that uses a struct mapped_device as a key.
390 static struct dm_thin_pool_table {
392 struct list_head pools;
393 } dm_thin_pool_table;
395 static void pool_table_init(void)
397 mutex_init(&dm_thin_pool_table.mutex);
398 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
401 static void __pool_table_insert(struct pool *pool)
403 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
404 list_add(&pool->list, &dm_thin_pool_table.pools);
407 static void __pool_table_remove(struct pool *pool)
409 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
410 list_del(&pool->list);
413 static struct pool *__pool_table_lookup(struct mapped_device *md)
415 struct pool *pool = NULL, *tmp;
417 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
419 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
420 if (tmp->pool_md == md) {
429 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
431 struct pool *pool = NULL, *tmp;
433 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
435 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
436 if (tmp->md_dev == md_dev) {
445 /*----------------------------------------------------------------*/
447 struct dm_thin_endio_hook {
449 struct dm_deferred_entry *shared_read_entry;
450 struct dm_deferred_entry *all_io_entry;
451 struct dm_thin_new_mapping *overwrite_mapping;
452 struct rb_node rb_node;
455 static void requeue_bio_list(struct thin_c *tc, struct bio_list *master)
458 struct bio_list bios;
461 bio_list_init(&bios);
463 spin_lock_irqsave(&tc->lock, flags);
464 bio_list_merge(&bios, master);
465 bio_list_init(master);
466 spin_unlock_irqrestore(&tc->lock, flags);
468 while ((bio = bio_list_pop(&bios)))
469 bio_endio(bio, DM_ENDIO_REQUEUE);
472 static void requeue_deferred_cells(struct thin_c *tc)
474 struct pool *pool = tc->pool;
476 struct list_head cells;
477 struct dm_bio_prison_cell *cell, *tmp;
479 INIT_LIST_HEAD(&cells);
481 spin_lock_irqsave(&tc->lock, flags);
482 list_splice_init(&tc->deferred_cells, &cells);
483 spin_unlock_irqrestore(&tc->lock, flags);
485 list_for_each_entry_safe(cell, tmp, &cells, user_list)
486 cell_requeue(pool, cell);
489 static void requeue_io(struct thin_c *tc)
491 requeue_bio_list(tc, &tc->deferred_bio_list);
492 requeue_bio_list(tc, &tc->retry_on_resume_list);
493 requeue_deferred_cells(tc);
496 static void error_thin_retry_list(struct thin_c *tc)
500 struct bio_list bios;
502 bio_list_init(&bios);
504 spin_lock_irqsave(&tc->lock, flags);
505 bio_list_merge(&bios, &tc->retry_on_resume_list);
506 bio_list_init(&tc->retry_on_resume_list);
507 spin_unlock_irqrestore(&tc->lock, flags);
509 while ((bio = bio_list_pop(&bios)))
513 static void error_retry_list(struct pool *pool)
518 list_for_each_entry_rcu(tc, &pool->active_thins, list)
519 error_thin_retry_list(tc);
524 * This section of code contains the logic for processing a thin device's IO.
525 * Much of the code depends on pool object resources (lists, workqueues, etc)
526 * but most is exclusively called from the thin target rather than the thin-pool
530 static bool block_size_is_power_of_two(struct pool *pool)
532 return pool->sectors_per_block_shift >= 0;
535 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
537 struct pool *pool = tc->pool;
538 sector_t block_nr = bio->bi_iter.bi_sector;
540 if (block_size_is_power_of_two(pool))
541 block_nr >>= pool->sectors_per_block_shift;
543 (void) sector_div(block_nr, pool->sectors_per_block);
548 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
550 struct pool *pool = tc->pool;
551 sector_t bi_sector = bio->bi_iter.bi_sector;
553 bio->bi_bdev = tc->pool_dev->bdev;
554 if (block_size_is_power_of_two(pool))
555 bio->bi_iter.bi_sector =
556 (block << pool->sectors_per_block_shift) |
557 (bi_sector & (pool->sectors_per_block - 1));
559 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
560 sector_div(bi_sector, pool->sectors_per_block);
563 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
565 bio->bi_bdev = tc->origin_dev->bdev;
568 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
570 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
571 dm_thin_changed_this_transaction(tc->td);
574 static void inc_all_io_entry(struct pool *pool, struct bio *bio)
576 struct dm_thin_endio_hook *h;
578 if (bio->bi_rw & REQ_DISCARD)
581 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
582 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
585 static void issue(struct thin_c *tc, struct bio *bio)
587 struct pool *pool = tc->pool;
590 if (!bio_triggers_commit(tc, bio)) {
591 generic_make_request(bio);
596 * Complete bio with an error if earlier I/O caused changes to
597 * the metadata that can't be committed e.g, due to I/O errors
598 * on the metadata device.
600 if (dm_thin_aborted_changes(tc->td)) {
606 * Batch together any bios that trigger commits and then issue a
607 * single commit for them in process_deferred_bios().
609 spin_lock_irqsave(&pool->lock, flags);
610 bio_list_add(&pool->deferred_flush_bios, bio);
611 spin_unlock_irqrestore(&pool->lock, flags);
614 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
616 remap_to_origin(tc, bio);
620 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
623 remap(tc, bio, block);
627 /*----------------------------------------------------------------*/
630 * Bio endio functions.
632 struct dm_thin_new_mapping {
633 struct list_head list;
636 bool definitely_not_shared:1;
639 * Track quiescing, copying and zeroing preparation actions. When this
640 * counter hits zero the block is prepared and can be inserted into the
643 atomic_t prepare_actions;
647 dm_block_t virt_block;
648 dm_block_t data_block;
649 struct dm_bio_prison_cell *cell, *cell2;
652 * If the bio covers the whole area of a block then we can avoid
653 * zeroing or copying. Instead this bio is hooked. The bio will
654 * still be in the cell, so care has to be taken to avoid issuing
658 bio_end_io_t *saved_bi_end_io;
661 static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
663 struct pool *pool = m->tc->pool;
665 if (atomic_dec_and_test(&m->prepare_actions)) {
666 list_add_tail(&m->list, &pool->prepared_mappings);
671 static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
674 struct pool *pool = m->tc->pool;
676 spin_lock_irqsave(&pool->lock, flags);
677 __complete_mapping_preparation(m);
678 spin_unlock_irqrestore(&pool->lock, flags);
681 static void copy_complete(int read_err, unsigned long write_err, void *context)
683 struct dm_thin_new_mapping *m = context;
685 m->err = read_err || write_err ? -EIO : 0;
686 complete_mapping_preparation(m);
689 static void overwrite_endio(struct bio *bio, int err)
691 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
692 struct dm_thin_new_mapping *m = h->overwrite_mapping;
695 complete_mapping_preparation(m);
698 /*----------------------------------------------------------------*/
705 * Prepared mapping jobs.
709 * This sends the bios in the cell, except the original holder, back
710 * to the deferred_bios list.
712 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
714 struct pool *pool = tc->pool;
717 spin_lock_irqsave(&tc->lock, flags);
718 cell_release_no_holder(pool, cell, &tc->deferred_bio_list);
719 spin_unlock_irqrestore(&tc->lock, flags);
724 static void thin_defer_bio(struct thin_c *tc, struct bio *bio);
728 struct bio_list defer_bios;
729 struct bio_list issue_bios;
732 static void __inc_remap_and_issue_cell(void *context,
733 struct dm_bio_prison_cell *cell)
735 struct remap_info *info = context;
738 while ((bio = bio_list_pop(&cell->bios))) {
739 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA))
740 bio_list_add(&info->defer_bios, bio);
742 inc_all_io_entry(info->tc->pool, bio);
745 * We can't issue the bios with the bio prison lock
746 * held, so we add them to a list to issue on
747 * return from this function.
749 bio_list_add(&info->issue_bios, bio);
754 static void inc_remap_and_issue_cell(struct thin_c *tc,
755 struct dm_bio_prison_cell *cell,
759 struct remap_info info;
762 bio_list_init(&info.defer_bios);
763 bio_list_init(&info.issue_bios);
766 * We have to be careful to inc any bios we're about to issue
767 * before the cell is released, and avoid a race with new bios
768 * being added to the cell.
770 cell_visit_release(tc->pool, __inc_remap_and_issue_cell,
773 while ((bio = bio_list_pop(&info.defer_bios)))
774 thin_defer_bio(tc, bio);
776 while ((bio = bio_list_pop(&info.issue_bios)))
777 remap_and_issue(info.tc, bio, block);
780 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
783 m->bio->bi_end_io = m->saved_bi_end_io;
784 atomic_inc(&m->bio->bi_remaining);
786 cell_error(m->tc->pool, m->cell);
788 mempool_free(m, m->tc->pool->mapping_pool);
791 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
793 struct thin_c *tc = m->tc;
794 struct pool *pool = tc->pool;
800 bio->bi_end_io = m->saved_bi_end_io;
801 atomic_inc(&bio->bi_remaining);
805 cell_error(pool, m->cell);
810 * Commit the prepared block into the mapping btree.
811 * Any I/O for this block arriving after this point will get
812 * remapped to it directly.
814 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
816 metadata_operation_failed(pool, "dm_thin_insert_block", r);
817 cell_error(pool, m->cell);
822 * Release any bios held while the block was being provisioned.
823 * If we are processing a write bio that completely covers the block,
824 * we already processed it so can ignore it now when processing
825 * the bios in the cell.
828 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
831 inc_all_io_entry(tc->pool, m->cell->holder);
832 remap_and_issue(tc, m->cell->holder, m->data_block);
833 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
838 mempool_free(m, pool->mapping_pool);
841 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
843 struct thin_c *tc = m->tc;
845 bio_io_error(m->bio);
846 cell_defer_no_holder(tc, m->cell);
847 cell_defer_no_holder(tc, m->cell2);
848 mempool_free(m, tc->pool->mapping_pool);
851 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
853 struct thin_c *tc = m->tc;
855 inc_all_io_entry(tc->pool, m->bio);
856 cell_defer_no_holder(tc, m->cell);
857 cell_defer_no_holder(tc, m->cell2);
860 if (m->definitely_not_shared)
861 remap_and_issue(tc, m->bio, m->data_block);
864 if (dm_pool_block_is_used(tc->pool->pmd, m->data_block, &used) || used)
865 bio_endio(m->bio, 0);
867 remap_and_issue(tc, m->bio, m->data_block);
870 bio_endio(m->bio, 0);
872 mempool_free(m, tc->pool->mapping_pool);
875 static void process_prepared_discard(struct dm_thin_new_mapping *m)
878 struct thin_c *tc = m->tc;
880 r = dm_thin_remove_block(tc->td, m->virt_block);
882 DMERR_LIMIT("dm_thin_remove_block() failed");
884 process_prepared_discard_passdown(m);
887 static void process_prepared(struct pool *pool, struct list_head *head,
888 process_mapping_fn *fn)
891 struct list_head maps;
892 struct dm_thin_new_mapping *m, *tmp;
894 INIT_LIST_HEAD(&maps);
895 spin_lock_irqsave(&pool->lock, flags);
896 list_splice_init(head, &maps);
897 spin_unlock_irqrestore(&pool->lock, flags);
899 list_for_each_entry_safe(m, tmp, &maps, list)
906 static int io_overlaps_block(struct pool *pool, struct bio *bio)
908 return bio->bi_iter.bi_size ==
909 (pool->sectors_per_block << SECTOR_SHIFT);
912 static int io_overwrites_block(struct pool *pool, struct bio *bio)
914 return (bio_data_dir(bio) == WRITE) &&
915 io_overlaps_block(pool, bio);
918 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
921 *save = bio->bi_end_io;
925 static int ensure_next_mapping(struct pool *pool)
927 if (pool->next_mapping)
930 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
932 return pool->next_mapping ? 0 : -ENOMEM;
935 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
937 struct dm_thin_new_mapping *m = pool->next_mapping;
939 BUG_ON(!pool->next_mapping);
941 memset(m, 0, sizeof(struct dm_thin_new_mapping));
942 INIT_LIST_HEAD(&m->list);
945 pool->next_mapping = NULL;
950 static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
951 sector_t begin, sector_t end)
954 struct dm_io_region to;
956 to.bdev = tc->pool_dev->bdev;
958 to.count = end - begin;
960 r = dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
962 DMERR_LIMIT("dm_kcopyd_zero() failed");
963 copy_complete(1, 1, m);
967 static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
968 dm_block_t data_block,
969 struct dm_thin_new_mapping *m)
971 struct pool *pool = tc->pool;
972 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
974 h->overwrite_mapping = m;
976 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
977 inc_all_io_entry(pool, bio);
978 remap_and_issue(tc, bio, data_block);
982 * A partial copy also needs to zero the uncopied region.
984 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
985 struct dm_dev *origin, dm_block_t data_origin,
986 dm_block_t data_dest,
987 struct dm_bio_prison_cell *cell, struct bio *bio,
991 struct pool *pool = tc->pool;
992 struct dm_thin_new_mapping *m = get_next_mapping(pool);
995 m->virt_block = virt_block;
996 m->data_block = data_dest;
1000 * quiesce action + copy action + an extra reference held for the
1001 * duration of this function (we may need to inc later for a
1004 atomic_set(&m->prepare_actions, 3);
1006 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
1007 complete_mapping_preparation(m); /* already quiesced */
1010 * IO to pool_dev remaps to the pool target's data_dev.
1012 * If the whole block of data is being overwritten, we can issue the
1013 * bio immediately. Otherwise we use kcopyd to clone the data first.
1015 if (io_overwrites_block(pool, bio))
1016 remap_and_issue_overwrite(tc, bio, data_dest, m);
1018 struct dm_io_region from, to;
1020 from.bdev = origin->bdev;
1021 from.sector = data_origin * pool->sectors_per_block;
1024 to.bdev = tc->pool_dev->bdev;
1025 to.sector = data_dest * pool->sectors_per_block;
1028 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
1029 0, copy_complete, m);
1031 DMERR_LIMIT("dm_kcopyd_copy() failed");
1032 copy_complete(1, 1, m);
1035 * We allow the zero to be issued, to simplify the
1036 * error path. Otherwise we'd need to start
1037 * worrying about decrementing the prepare_actions
1043 * Do we need to zero a tail region?
1045 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
1046 atomic_inc(&m->prepare_actions);
1048 data_dest * pool->sectors_per_block + len,
1049 (data_dest + 1) * pool->sectors_per_block);
1053 complete_mapping_preparation(m); /* drop our ref */
1056 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
1057 dm_block_t data_origin, dm_block_t data_dest,
1058 struct dm_bio_prison_cell *cell, struct bio *bio)
1060 schedule_copy(tc, virt_block, tc->pool_dev,
1061 data_origin, data_dest, cell, bio,
1062 tc->pool->sectors_per_block);
1065 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
1066 dm_block_t data_block, struct dm_bio_prison_cell *cell,
1069 struct pool *pool = tc->pool;
1070 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1072 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
1074 m->virt_block = virt_block;
1075 m->data_block = data_block;
1079 * If the whole block of data is being overwritten or we are not
1080 * zeroing pre-existing data, we can issue the bio immediately.
1081 * Otherwise we use kcopyd to zero the data first.
1083 if (!pool->pf.zero_new_blocks)
1084 process_prepared_mapping(m);
1086 else if (io_overwrites_block(pool, bio))
1087 remap_and_issue_overwrite(tc, bio, data_block, m);
1091 data_block * pool->sectors_per_block,
1092 (data_block + 1) * pool->sectors_per_block);
1095 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1096 dm_block_t data_dest,
1097 struct dm_bio_prison_cell *cell, struct bio *bio)
1099 struct pool *pool = tc->pool;
1100 sector_t virt_block_begin = virt_block * pool->sectors_per_block;
1101 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
1103 if (virt_block_end <= tc->origin_size)
1104 schedule_copy(tc, virt_block, tc->origin_dev,
1105 virt_block, data_dest, cell, bio,
1106 pool->sectors_per_block);
1108 else if (virt_block_begin < tc->origin_size)
1109 schedule_copy(tc, virt_block, tc->origin_dev,
1110 virt_block, data_dest, cell, bio,
1111 tc->origin_size - virt_block_begin);
1114 schedule_zero(tc, virt_block, data_dest, cell, bio);
1118 * A non-zero return indicates read_only or fail_io mode.
1119 * Many callers don't care about the return value.
1121 static int commit(struct pool *pool)
1125 if (get_pool_mode(pool) >= PM_READ_ONLY)
1128 r = dm_pool_commit_metadata(pool->pmd);
1130 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
1135 static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
1137 unsigned long flags;
1139 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1140 DMWARN("%s: reached low water mark for data device: sending event.",
1141 dm_device_name(pool->pool_md));
1142 spin_lock_irqsave(&pool->lock, flags);
1143 pool->low_water_triggered = true;
1144 spin_unlock_irqrestore(&pool->lock, flags);
1145 dm_table_event(pool->ti->table);
1149 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
1151 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1154 dm_block_t free_blocks;
1155 struct pool *pool = tc->pool;
1157 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
1160 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1162 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1166 check_low_water_mark(pool, free_blocks);
1170 * Try to commit to see if that will free up some
1177 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1179 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1184 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1189 r = dm_pool_alloc_data_block(pool->pmd, result);
1191 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1199 * If we have run out of space, queue bios until the device is
1200 * resumed, presumably after having been reloaded with more space.
1202 static void retry_on_resume(struct bio *bio)
1204 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1205 struct thin_c *tc = h->tc;
1206 unsigned long flags;
1208 spin_lock_irqsave(&tc->lock, flags);
1209 bio_list_add(&tc->retry_on_resume_list, bio);
1210 spin_unlock_irqrestore(&tc->lock, flags);
1213 static int should_error_unserviceable_bio(struct pool *pool)
1215 enum pool_mode m = get_pool_mode(pool);
1219 /* Shouldn't get here */
1220 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1223 case PM_OUT_OF_DATA_SPACE:
1224 return pool->pf.error_if_no_space ? -ENOSPC : 0;
1230 /* Shouldn't get here */
1231 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1236 static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1238 int error = should_error_unserviceable_bio(pool);
1241 bio_endio(bio, error);
1243 retry_on_resume(bio);
1246 static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1249 struct bio_list bios;
1252 error = should_error_unserviceable_bio(pool);
1254 cell_error_with_code(pool, cell, error);
1258 bio_list_init(&bios);
1259 cell_release(pool, cell, &bios);
1261 error = should_error_unserviceable_bio(pool);
1263 while ((bio = bio_list_pop(&bios)))
1264 bio_endio(bio, error);
1266 while ((bio = bio_list_pop(&bios)))
1267 retry_on_resume(bio);
1270 static void process_discard_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1273 struct bio *bio = cell->holder;
1274 struct pool *pool = tc->pool;
1275 struct dm_bio_prison_cell *cell2;
1276 struct dm_cell_key key2;
1277 dm_block_t block = get_bio_block(tc, bio);
1278 struct dm_thin_lookup_result lookup_result;
1279 struct dm_thin_new_mapping *m;
1281 if (tc->requeue_mode) {
1282 cell_requeue(pool, cell);
1286 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1290 * Check nobody is fiddling with this pool block. This can
1291 * happen if someone's in the process of breaking sharing
1294 build_data_key(tc->td, lookup_result.block, &key2);
1295 if (bio_detain(tc->pool, &key2, bio, &cell2)) {
1296 cell_defer_no_holder(tc, cell);
1300 if (io_overlaps_block(pool, bio)) {
1302 * IO may still be going to the destination block. We must
1303 * quiesce before we can do the removal.
1305 m = get_next_mapping(pool);
1307 m->pass_discard = pool->pf.discard_passdown;
1308 m->definitely_not_shared = !lookup_result.shared;
1309 m->virt_block = block;
1310 m->data_block = lookup_result.block;
1315 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1316 pool->process_prepared_discard(m);
1319 inc_all_io_entry(pool, bio);
1320 cell_defer_no_holder(tc, cell);
1321 cell_defer_no_holder(tc, cell2);
1324 * The DM core makes sure that the discard doesn't span
1325 * a block boundary. So we submit the discard of a
1326 * partial block appropriately.
1328 if ((!lookup_result.shared) && pool->pf.discard_passdown)
1329 remap_and_issue(tc, bio, lookup_result.block);
1337 * It isn't provisioned, just forget it.
1339 cell_defer_no_holder(tc, cell);
1344 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1346 cell_defer_no_holder(tc, cell);
1352 static void process_discard_bio(struct thin_c *tc, struct bio *bio)
1354 struct dm_bio_prison_cell *cell;
1355 struct dm_cell_key key;
1356 dm_block_t block = get_bio_block(tc, bio);
1358 build_virtual_key(tc->td, block, &key);
1359 if (bio_detain(tc->pool, &key, bio, &cell))
1362 process_discard_cell(tc, cell);
1365 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1366 struct dm_cell_key *key,
1367 struct dm_thin_lookup_result *lookup_result,
1368 struct dm_bio_prison_cell *cell)
1371 dm_block_t data_block;
1372 struct pool *pool = tc->pool;
1374 r = alloc_data_block(tc, &data_block);
1377 schedule_internal_copy(tc, block, lookup_result->block,
1378 data_block, cell, bio);
1382 retry_bios_on_resume(pool, cell);
1386 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1388 cell_error(pool, cell);
1393 static void __remap_and_issue_shared_cell(void *context,
1394 struct dm_bio_prison_cell *cell)
1396 struct remap_info *info = context;
1399 while ((bio = bio_list_pop(&cell->bios))) {
1400 if ((bio_data_dir(bio) == WRITE) ||
1401 (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)))
1402 bio_list_add(&info->defer_bios, bio);
1404 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));;
1406 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds);
1407 inc_all_io_entry(info->tc->pool, bio);
1408 bio_list_add(&info->issue_bios, bio);
1413 static void remap_and_issue_shared_cell(struct thin_c *tc,
1414 struct dm_bio_prison_cell *cell,
1418 struct remap_info info;
1421 bio_list_init(&info.defer_bios);
1422 bio_list_init(&info.issue_bios);
1424 cell_visit_release(tc->pool, __remap_and_issue_shared_cell,
1427 while ((bio = bio_list_pop(&info.defer_bios)))
1428 thin_defer_bio(tc, bio);
1430 while ((bio = bio_list_pop(&info.issue_bios)))
1431 remap_and_issue(tc, bio, block);
1434 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1436 struct dm_thin_lookup_result *lookup_result,
1437 struct dm_bio_prison_cell *virt_cell)
1439 struct dm_bio_prison_cell *data_cell;
1440 struct pool *pool = tc->pool;
1441 struct dm_cell_key key;
1444 * If cell is already occupied, then sharing is already in the process
1445 * of being broken so we have nothing further to do here.
1447 build_data_key(tc->td, lookup_result->block, &key);
1448 if (bio_detain(pool, &key, bio, &data_cell)) {
1449 cell_defer_no_holder(tc, virt_cell);
1453 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) {
1454 break_sharing(tc, bio, block, &key, lookup_result, data_cell);
1455 cell_defer_no_holder(tc, virt_cell);
1457 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1459 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1460 inc_all_io_entry(pool, bio);
1461 remap_and_issue(tc, bio, lookup_result->block);
1463 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block);
1464 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block);
1468 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1469 struct dm_bio_prison_cell *cell)
1472 dm_block_t data_block;
1473 struct pool *pool = tc->pool;
1476 * Remap empty bios (flushes) immediately, without provisioning.
1478 if (!bio->bi_iter.bi_size) {
1479 inc_all_io_entry(pool, bio);
1480 cell_defer_no_holder(tc, cell);
1482 remap_and_issue(tc, bio, 0);
1487 * Fill read bios with zeroes and complete them immediately.
1489 if (bio_data_dir(bio) == READ) {
1491 cell_defer_no_holder(tc, cell);
1496 r = alloc_data_block(tc, &data_block);
1500 schedule_external_copy(tc, block, data_block, cell, bio);
1502 schedule_zero(tc, block, data_block, cell, bio);
1506 retry_bios_on_resume(pool, cell);
1510 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1512 cell_error(pool, cell);
1517 static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1520 struct pool *pool = tc->pool;
1521 struct bio *bio = cell->holder;
1522 dm_block_t block = get_bio_block(tc, bio);
1523 struct dm_thin_lookup_result lookup_result;
1525 if (tc->requeue_mode) {
1526 cell_requeue(pool, cell);
1530 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1533 if (lookup_result.shared)
1534 process_shared_bio(tc, bio, block, &lookup_result, cell);
1536 inc_all_io_entry(pool, bio);
1537 remap_and_issue(tc, bio, lookup_result.block);
1538 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1543 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1544 inc_all_io_entry(pool, bio);
1545 cell_defer_no_holder(tc, cell);
1547 if (bio_end_sector(bio) <= tc->origin_size)
1548 remap_to_origin_and_issue(tc, bio);
1550 else if (bio->bi_iter.bi_sector < tc->origin_size) {
1552 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
1553 remap_to_origin_and_issue(tc, bio);
1560 provision_block(tc, bio, block, cell);
1564 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1566 cell_defer_no_holder(tc, cell);
1572 static void process_bio(struct thin_c *tc, struct bio *bio)
1574 struct pool *pool = tc->pool;
1575 dm_block_t block = get_bio_block(tc, bio);
1576 struct dm_bio_prison_cell *cell;
1577 struct dm_cell_key key;
1580 * If cell is already occupied, then the block is already
1581 * being provisioned so we have nothing further to do here.
1583 build_virtual_key(tc->td, block, &key);
1584 if (bio_detain(pool, &key, bio, &cell))
1587 process_cell(tc, cell);
1590 static void __process_bio_read_only(struct thin_c *tc, struct bio *bio,
1591 struct dm_bio_prison_cell *cell)
1594 int rw = bio_data_dir(bio);
1595 dm_block_t block = get_bio_block(tc, bio);
1596 struct dm_thin_lookup_result lookup_result;
1598 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1601 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) {
1602 handle_unserviceable_bio(tc->pool, bio);
1604 cell_defer_no_holder(tc, cell);
1606 inc_all_io_entry(tc->pool, bio);
1607 remap_and_issue(tc, bio, lookup_result.block);
1609 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1615 cell_defer_no_holder(tc, cell);
1617 handle_unserviceable_bio(tc->pool, bio);
1621 if (tc->origin_dev) {
1622 inc_all_io_entry(tc->pool, bio);
1623 remap_to_origin_and_issue(tc, bio);
1632 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1635 cell_defer_no_holder(tc, cell);
1641 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1643 __process_bio_read_only(tc, bio, NULL);
1646 static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1648 __process_bio_read_only(tc, cell->holder, cell);
1651 static void process_bio_success(struct thin_c *tc, struct bio *bio)
1656 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1661 static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1663 cell_success(tc->pool, cell);
1666 static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1668 cell_error(tc->pool, cell);
1672 * FIXME: should we also commit due to size of transaction, measured in
1675 static int need_commit_due_to_time(struct pool *pool)
1677 return jiffies < pool->last_commit_jiffies ||
1678 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1681 #define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
1682 #define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
1684 static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
1686 struct rb_node **rbp, *parent;
1687 struct dm_thin_endio_hook *pbd;
1688 sector_t bi_sector = bio->bi_iter.bi_sector;
1690 rbp = &tc->sort_bio_list.rb_node;
1694 pbd = thin_pbd(parent);
1696 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
1697 rbp = &(*rbp)->rb_left;
1699 rbp = &(*rbp)->rb_right;
1702 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1703 rb_link_node(&pbd->rb_node, parent, rbp);
1704 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
1707 static void __extract_sorted_bios(struct thin_c *tc)
1709 struct rb_node *node;
1710 struct dm_thin_endio_hook *pbd;
1713 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
1714 pbd = thin_pbd(node);
1715 bio = thin_bio(pbd);
1717 bio_list_add(&tc->deferred_bio_list, bio);
1718 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
1721 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
1724 static void __sort_thin_deferred_bios(struct thin_c *tc)
1727 struct bio_list bios;
1729 bio_list_init(&bios);
1730 bio_list_merge(&bios, &tc->deferred_bio_list);
1731 bio_list_init(&tc->deferred_bio_list);
1733 /* Sort deferred_bio_list using rb-tree */
1734 while ((bio = bio_list_pop(&bios)))
1735 __thin_bio_rb_add(tc, bio);
1738 * Transfer the sorted bios in sort_bio_list back to
1739 * deferred_bio_list to allow lockless submission of
1742 __extract_sorted_bios(tc);
1745 static void process_thin_deferred_bios(struct thin_c *tc)
1747 struct pool *pool = tc->pool;
1748 unsigned long flags;
1750 struct bio_list bios;
1751 struct blk_plug plug;
1754 if (tc->requeue_mode) {
1755 requeue_bio_list(tc, &tc->deferred_bio_list);
1759 bio_list_init(&bios);
1761 spin_lock_irqsave(&tc->lock, flags);
1763 if (bio_list_empty(&tc->deferred_bio_list)) {
1764 spin_unlock_irqrestore(&tc->lock, flags);
1768 __sort_thin_deferred_bios(tc);
1770 bio_list_merge(&bios, &tc->deferred_bio_list);
1771 bio_list_init(&tc->deferred_bio_list);
1773 spin_unlock_irqrestore(&tc->lock, flags);
1775 blk_start_plug(&plug);
1776 while ((bio = bio_list_pop(&bios))) {
1778 * If we've got no free new_mapping structs, and processing
1779 * this bio might require one, we pause until there are some
1780 * prepared mappings to process.
1782 if (ensure_next_mapping(pool)) {
1783 spin_lock_irqsave(&tc->lock, flags);
1784 bio_list_add(&tc->deferred_bio_list, bio);
1785 bio_list_merge(&tc->deferred_bio_list, &bios);
1786 spin_unlock_irqrestore(&tc->lock, flags);
1790 if (bio->bi_rw & REQ_DISCARD)
1791 pool->process_discard(tc, bio);
1793 pool->process_bio(tc, bio);
1795 if ((count++ & 127) == 0) {
1796 throttle_work_update(&pool->throttle);
1797 dm_pool_issue_prefetches(pool->pmd);
1800 blk_finish_plug(&plug);
1803 static void process_thin_deferred_cells(struct thin_c *tc)
1805 struct pool *pool = tc->pool;
1806 unsigned long flags;
1807 struct list_head cells;
1808 struct dm_bio_prison_cell *cell, *tmp;
1810 INIT_LIST_HEAD(&cells);
1812 spin_lock_irqsave(&tc->lock, flags);
1813 list_splice_init(&tc->deferred_cells, &cells);
1814 spin_unlock_irqrestore(&tc->lock, flags);
1816 if (list_empty(&cells))
1819 list_for_each_entry_safe(cell, tmp, &cells, user_list) {
1820 BUG_ON(!cell->holder);
1823 * If we've got no free new_mapping structs, and processing
1824 * this bio might require one, we pause until there are some
1825 * prepared mappings to process.
1827 if (ensure_next_mapping(pool)) {
1828 spin_lock_irqsave(&tc->lock, flags);
1829 list_add(&cell->user_list, &tc->deferred_cells);
1830 list_splice(&cells, &tc->deferred_cells);
1831 spin_unlock_irqrestore(&tc->lock, flags);
1835 if (cell->holder->bi_rw & REQ_DISCARD)
1836 pool->process_discard_cell(tc, cell);
1838 pool->process_cell(tc, cell);
1842 static void thin_get(struct thin_c *tc);
1843 static void thin_put(struct thin_c *tc);
1846 * We can't hold rcu_read_lock() around code that can block. So we
1847 * find a thin with the rcu lock held; bump a refcount; then drop
1850 static struct thin_c *get_first_thin(struct pool *pool)
1852 struct thin_c *tc = NULL;
1855 if (!list_empty(&pool->active_thins)) {
1856 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
1864 static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
1866 struct thin_c *old_tc = tc;
1869 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
1881 static void process_deferred_bios(struct pool *pool)
1883 unsigned long flags;
1885 struct bio_list bios;
1888 tc = get_first_thin(pool);
1890 process_thin_deferred_cells(tc);
1891 process_thin_deferred_bios(tc);
1892 tc = get_next_thin(pool, tc);
1896 * If there are any deferred flush bios, we must commit
1897 * the metadata before issuing them.
1899 bio_list_init(&bios);
1900 spin_lock_irqsave(&pool->lock, flags);
1901 bio_list_merge(&bios, &pool->deferred_flush_bios);
1902 bio_list_init(&pool->deferred_flush_bios);
1903 spin_unlock_irqrestore(&pool->lock, flags);
1905 if (bio_list_empty(&bios) &&
1906 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
1910 while ((bio = bio_list_pop(&bios)))
1914 pool->last_commit_jiffies = jiffies;
1916 while ((bio = bio_list_pop(&bios)))
1917 generic_make_request(bio);
1920 static void do_worker(struct work_struct *ws)
1922 struct pool *pool = container_of(ws, struct pool, worker);
1924 throttle_work_start(&pool->throttle);
1925 dm_pool_issue_prefetches(pool->pmd);
1926 throttle_work_update(&pool->throttle);
1927 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1928 throttle_work_update(&pool->throttle);
1929 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1930 throttle_work_update(&pool->throttle);
1931 process_deferred_bios(pool);
1932 throttle_work_complete(&pool->throttle);
1936 * We want to commit periodically so that not too much
1937 * unwritten data builds up.
1939 static void do_waker(struct work_struct *ws)
1941 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1943 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1947 * We're holding onto IO to allow userland time to react. After the
1948 * timeout either the pool will have been resized (and thus back in
1949 * PM_WRITE mode), or we degrade to PM_READ_ONLY and start erroring IO.
1951 static void do_no_space_timeout(struct work_struct *ws)
1953 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
1956 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space)
1957 set_pool_mode(pool, PM_READ_ONLY);
1960 /*----------------------------------------------------------------*/
1963 struct work_struct worker;
1964 struct completion complete;
1967 static struct pool_work *to_pool_work(struct work_struct *ws)
1969 return container_of(ws, struct pool_work, worker);
1972 static void pool_work_complete(struct pool_work *pw)
1974 complete(&pw->complete);
1977 static void pool_work_wait(struct pool_work *pw, struct pool *pool,
1978 void (*fn)(struct work_struct *))
1980 INIT_WORK_ONSTACK(&pw->worker, fn);
1981 init_completion(&pw->complete);
1982 queue_work(pool->wq, &pw->worker);
1983 wait_for_completion(&pw->complete);
1986 /*----------------------------------------------------------------*/
1988 struct noflush_work {
1989 struct pool_work pw;
1993 static struct noflush_work *to_noflush(struct work_struct *ws)
1995 return container_of(to_pool_work(ws), struct noflush_work, pw);
1998 static void do_noflush_start(struct work_struct *ws)
2000 struct noflush_work *w = to_noflush(ws);
2001 w->tc->requeue_mode = true;
2003 pool_work_complete(&w->pw);
2006 static void do_noflush_stop(struct work_struct *ws)
2008 struct noflush_work *w = to_noflush(ws);
2009 w->tc->requeue_mode = false;
2010 pool_work_complete(&w->pw);
2013 static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
2015 struct noflush_work w;
2018 pool_work_wait(&w.pw, tc->pool, fn);
2021 /*----------------------------------------------------------------*/
2023 static enum pool_mode get_pool_mode(struct pool *pool)
2025 return pool->pf.mode;
2028 static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode)
2030 dm_table_event(pool->ti->table);
2031 DMINFO("%s: switching pool to %s mode",
2032 dm_device_name(pool->pool_md), new_mode);
2035 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
2037 struct pool_c *pt = pool->ti->private;
2038 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
2039 enum pool_mode old_mode = get_pool_mode(pool);
2040 unsigned long no_space_timeout = ACCESS_ONCE(no_space_timeout_secs) * HZ;
2043 * Never allow the pool to transition to PM_WRITE mode if user
2044 * intervention is required to verify metadata and data consistency.
2046 if (new_mode == PM_WRITE && needs_check) {
2047 DMERR("%s: unable to switch pool to write mode until repaired.",
2048 dm_device_name(pool->pool_md));
2049 if (old_mode != new_mode)
2050 new_mode = old_mode;
2052 new_mode = PM_READ_ONLY;
2055 * If we were in PM_FAIL mode, rollback of metadata failed. We're
2056 * not going to recover without a thin_repair. So we never let the
2057 * pool move out of the old mode.
2059 if (old_mode == PM_FAIL)
2060 new_mode = old_mode;
2064 if (old_mode != new_mode)
2065 notify_of_pool_mode_change(pool, "failure");
2066 dm_pool_metadata_read_only(pool->pmd);
2067 pool->process_bio = process_bio_fail;
2068 pool->process_discard = process_bio_fail;
2069 pool->process_cell = process_cell_fail;
2070 pool->process_discard_cell = process_cell_fail;
2071 pool->process_prepared_mapping = process_prepared_mapping_fail;
2072 pool->process_prepared_discard = process_prepared_discard_fail;
2074 error_retry_list(pool);
2078 if (old_mode != new_mode)
2079 notify_of_pool_mode_change(pool, "read-only");
2080 dm_pool_metadata_read_only(pool->pmd);
2081 pool->process_bio = process_bio_read_only;
2082 pool->process_discard = process_bio_success;
2083 pool->process_cell = process_cell_read_only;
2084 pool->process_discard_cell = process_cell_success;
2085 pool->process_prepared_mapping = process_prepared_mapping_fail;
2086 pool->process_prepared_discard = process_prepared_discard_passdown;
2088 error_retry_list(pool);
2091 case PM_OUT_OF_DATA_SPACE:
2093 * Ideally we'd never hit this state; the low water mark
2094 * would trigger userland to extend the pool before we
2095 * completely run out of data space. However, many small
2096 * IOs to unprovisioned space can consume data space at an
2097 * alarming rate. Adjust your low water mark if you're
2098 * frequently seeing this mode.
2100 if (old_mode != new_mode)
2101 notify_of_pool_mode_change(pool, "out-of-data-space");
2102 pool->process_bio = process_bio_read_only;
2103 pool->process_discard = process_discard_bio;
2104 pool->process_cell = process_cell_read_only;
2105 pool->process_discard_cell = process_discard_cell;
2106 pool->process_prepared_mapping = process_prepared_mapping;
2107 pool->process_prepared_discard = process_prepared_discard_passdown;
2109 if (!pool->pf.error_if_no_space && no_space_timeout)
2110 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
2114 if (old_mode != new_mode)
2115 notify_of_pool_mode_change(pool, "write");
2116 dm_pool_metadata_read_write(pool->pmd);
2117 pool->process_bio = process_bio;
2118 pool->process_discard = process_discard_bio;
2119 pool->process_cell = process_cell;
2120 pool->process_discard_cell = process_discard_cell;
2121 pool->process_prepared_mapping = process_prepared_mapping;
2122 pool->process_prepared_discard = process_prepared_discard;
2126 pool->pf.mode = new_mode;
2128 * The pool mode may have changed, sync it so bind_control_target()
2129 * doesn't cause an unexpected mode transition on resume.
2131 pt->adjusted_pf.mode = new_mode;
2134 static void abort_transaction(struct pool *pool)
2136 const char *dev_name = dm_device_name(pool->pool_md);
2138 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
2139 if (dm_pool_abort_metadata(pool->pmd)) {
2140 DMERR("%s: failed to abort metadata transaction", dev_name);
2141 set_pool_mode(pool, PM_FAIL);
2144 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
2145 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
2146 set_pool_mode(pool, PM_FAIL);
2150 static void metadata_operation_failed(struct pool *pool, const char *op, int r)
2152 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
2153 dm_device_name(pool->pool_md), op, r);
2155 abort_transaction(pool);
2156 set_pool_mode(pool, PM_READ_ONLY);
2159 /*----------------------------------------------------------------*/
2162 * Mapping functions.
2166 * Called only while mapping a thin bio to hand it over to the workqueue.
2168 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
2170 unsigned long flags;
2171 struct pool *pool = tc->pool;
2173 spin_lock_irqsave(&tc->lock, flags);
2174 bio_list_add(&tc->deferred_bio_list, bio);
2175 spin_unlock_irqrestore(&tc->lock, flags);
2180 static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
2182 struct pool *pool = tc->pool;
2184 throttle_lock(&pool->throttle);
2185 thin_defer_bio(tc, bio);
2186 throttle_unlock(&pool->throttle);
2189 static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2191 unsigned long flags;
2192 struct pool *pool = tc->pool;
2194 throttle_lock(&pool->throttle);
2195 spin_lock_irqsave(&tc->lock, flags);
2196 list_add_tail(&cell->user_list, &tc->deferred_cells);
2197 spin_unlock_irqrestore(&tc->lock, flags);
2198 throttle_unlock(&pool->throttle);
2203 static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
2205 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2208 h->shared_read_entry = NULL;
2209 h->all_io_entry = NULL;
2210 h->overwrite_mapping = NULL;
2214 * Non-blocking function called from the thin target's map function.
2216 static int thin_bio_map(struct dm_target *ti, struct bio *bio)
2219 struct thin_c *tc = ti->private;
2220 dm_block_t block = get_bio_block(tc, bio);
2221 struct dm_thin_device *td = tc->td;
2222 struct dm_thin_lookup_result result;
2223 struct dm_bio_prison_cell *virt_cell, *data_cell;
2224 struct dm_cell_key key;
2226 thin_hook_bio(tc, bio);
2228 if (tc->requeue_mode) {
2229 bio_endio(bio, DM_ENDIO_REQUEUE);
2230 return DM_MAPIO_SUBMITTED;
2233 if (get_pool_mode(tc->pool) == PM_FAIL) {
2235 return DM_MAPIO_SUBMITTED;
2238 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
2239 thin_defer_bio_with_throttle(tc, bio);
2240 return DM_MAPIO_SUBMITTED;
2244 * We must hold the virtual cell before doing the lookup, otherwise
2245 * there's a race with discard.
2247 build_virtual_key(tc->td, block, &key);
2248 if (bio_detain(tc->pool, &key, bio, &virt_cell))
2249 return DM_MAPIO_SUBMITTED;
2251 r = dm_thin_find_block(td, block, 0, &result);
2254 * Note that we defer readahead too.
2258 if (unlikely(result.shared)) {
2260 * We have a race condition here between the
2261 * result.shared value returned by the lookup and
2262 * snapshot creation, which may cause new
2265 * To avoid this always quiesce the origin before
2266 * taking the snap. You want to do this anyway to
2267 * ensure a consistent application view
2270 * More distant ancestors are irrelevant. The
2271 * shared flag will be set in their case.
2273 thin_defer_cell(tc, virt_cell);
2274 return DM_MAPIO_SUBMITTED;
2277 build_data_key(tc->td, result.block, &key);
2278 if (bio_detain(tc->pool, &key, bio, &data_cell)) {
2279 cell_defer_no_holder(tc, virt_cell);
2280 return DM_MAPIO_SUBMITTED;
2283 inc_all_io_entry(tc->pool, bio);
2284 cell_defer_no_holder(tc, data_cell);
2285 cell_defer_no_holder(tc, virt_cell);
2287 remap(tc, bio, result.block);
2288 return DM_MAPIO_REMAPPED;
2291 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
2293 * This block isn't provisioned, and we have no way
2296 handle_unserviceable_bio(tc->pool, bio);
2297 cell_defer_no_holder(tc, virt_cell);
2298 return DM_MAPIO_SUBMITTED;
2303 thin_defer_cell(tc, virt_cell);
2304 return DM_MAPIO_SUBMITTED;
2308 * Must always call bio_io_error on failure.
2309 * dm_thin_find_block can fail with -EINVAL if the
2310 * pool is switched to fail-io mode.
2313 cell_defer_no_holder(tc, virt_cell);
2314 return DM_MAPIO_SUBMITTED;
2318 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
2320 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
2321 struct request_queue *q;
2323 if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE)
2326 q = bdev_get_queue(pt->data_dev->bdev);
2327 return bdi_congested(&q->backing_dev_info, bdi_bits);
2330 static void requeue_bios(struct pool *pool)
2332 unsigned long flags;
2336 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
2337 spin_lock_irqsave(&tc->lock, flags);
2338 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
2339 bio_list_init(&tc->retry_on_resume_list);
2340 spin_unlock_irqrestore(&tc->lock, flags);
2345 /*----------------------------------------------------------------
2346 * Binding of control targets to a pool object
2347 *--------------------------------------------------------------*/
2348 static bool data_dev_supports_discard(struct pool_c *pt)
2350 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2352 return q && blk_queue_discard(q);
2355 static bool is_factor(sector_t block_size, uint32_t n)
2357 return !sector_div(block_size, n);
2361 * If discard_passdown was enabled verify that the data device
2362 * supports discards. Disable discard_passdown if not.
2364 static void disable_passdown_if_not_supported(struct pool_c *pt)
2366 struct pool *pool = pt->pool;
2367 struct block_device *data_bdev = pt->data_dev->bdev;
2368 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
2369 sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
2370 const char *reason = NULL;
2371 char buf[BDEVNAME_SIZE];
2373 if (!pt->adjusted_pf.discard_passdown)
2376 if (!data_dev_supports_discard(pt))
2377 reason = "discard unsupported";
2379 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
2380 reason = "max discard sectors smaller than a block";
2382 else if (data_limits->discard_granularity > block_size)
2383 reason = "discard granularity larger than a block";
2385 else if (!is_factor(block_size, data_limits->discard_granularity))
2386 reason = "discard granularity not a factor of block size";
2389 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
2390 pt->adjusted_pf.discard_passdown = false;
2394 static int bind_control_target(struct pool *pool, struct dm_target *ti)
2396 struct pool_c *pt = ti->private;
2399 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2401 enum pool_mode old_mode = get_pool_mode(pool);
2402 enum pool_mode new_mode = pt->adjusted_pf.mode;
2405 * Don't change the pool's mode until set_pool_mode() below.
2406 * Otherwise the pool's process_* function pointers may
2407 * not match the desired pool mode.
2409 pt->adjusted_pf.mode = old_mode;
2412 pool->pf = pt->adjusted_pf;
2413 pool->low_water_blocks = pt->low_water_blocks;
2415 set_pool_mode(pool, new_mode);
2420 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2426 /*----------------------------------------------------------------
2428 *--------------------------------------------------------------*/
2429 /* Initialize pool features. */
2430 static void pool_features_init(struct pool_features *pf)
2432 pf->mode = PM_WRITE;
2433 pf->zero_new_blocks = true;
2434 pf->discard_enabled = true;
2435 pf->discard_passdown = true;
2436 pf->error_if_no_space = false;
2439 static void __pool_destroy(struct pool *pool)
2441 __pool_table_remove(pool);
2443 if (dm_pool_metadata_close(pool->pmd) < 0)
2444 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2446 dm_bio_prison_destroy(pool->prison);
2447 dm_kcopyd_client_destroy(pool->copier);
2450 destroy_workqueue(pool->wq);
2452 if (pool->next_mapping)
2453 mempool_free(pool->next_mapping, pool->mapping_pool);
2454 mempool_destroy(pool->mapping_pool);
2455 dm_deferred_set_destroy(pool->shared_read_ds);
2456 dm_deferred_set_destroy(pool->all_io_ds);
2460 static struct kmem_cache *_new_mapping_cache;
2462 static struct pool *pool_create(struct mapped_device *pool_md,
2463 struct block_device *metadata_dev,
2464 unsigned long block_size,
2465 int read_only, char **error)
2470 struct dm_pool_metadata *pmd;
2471 bool format_device = read_only ? false : true;
2473 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2475 *error = "Error creating metadata object";
2476 return (struct pool *)pmd;
2479 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
2481 *error = "Error allocating memory for pool";
2482 err_p = ERR_PTR(-ENOMEM);
2487 pool->sectors_per_block = block_size;
2488 if (block_size & (block_size - 1))
2489 pool->sectors_per_block_shift = -1;
2491 pool->sectors_per_block_shift = __ffs(block_size);
2492 pool->low_water_blocks = 0;
2493 pool_features_init(&pool->pf);
2494 pool->prison = dm_bio_prison_create();
2495 if (!pool->prison) {
2496 *error = "Error creating pool's bio prison";
2497 err_p = ERR_PTR(-ENOMEM);
2501 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2502 if (IS_ERR(pool->copier)) {
2503 r = PTR_ERR(pool->copier);
2504 *error = "Error creating pool's kcopyd client";
2506 goto bad_kcopyd_client;
2510 * Create singlethreaded workqueue that will service all devices
2511 * that use this metadata.
2513 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2515 *error = "Error creating pool's workqueue";
2516 err_p = ERR_PTR(-ENOMEM);
2520 throttle_init(&pool->throttle);
2521 INIT_WORK(&pool->worker, do_worker);
2522 INIT_DELAYED_WORK(&pool->waker, do_waker);
2523 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
2524 spin_lock_init(&pool->lock);
2525 bio_list_init(&pool->deferred_flush_bios);
2526 INIT_LIST_HEAD(&pool->prepared_mappings);
2527 INIT_LIST_HEAD(&pool->prepared_discards);
2528 INIT_LIST_HEAD(&pool->active_thins);
2529 pool->low_water_triggered = false;
2531 pool->shared_read_ds = dm_deferred_set_create();
2532 if (!pool->shared_read_ds) {
2533 *error = "Error creating pool's shared read deferred set";
2534 err_p = ERR_PTR(-ENOMEM);
2535 goto bad_shared_read_ds;
2538 pool->all_io_ds = dm_deferred_set_create();
2539 if (!pool->all_io_ds) {
2540 *error = "Error creating pool's all io deferred set";
2541 err_p = ERR_PTR(-ENOMEM);
2545 pool->next_mapping = NULL;
2546 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
2547 _new_mapping_cache);
2548 if (!pool->mapping_pool) {
2549 *error = "Error creating pool's mapping mempool";
2550 err_p = ERR_PTR(-ENOMEM);
2551 goto bad_mapping_pool;
2554 pool->ref_count = 1;
2555 pool->last_commit_jiffies = jiffies;
2556 pool->pool_md = pool_md;
2557 pool->md_dev = metadata_dev;
2558 __pool_table_insert(pool);
2563 dm_deferred_set_destroy(pool->all_io_ds);
2565 dm_deferred_set_destroy(pool->shared_read_ds);
2567 destroy_workqueue(pool->wq);
2569 dm_kcopyd_client_destroy(pool->copier);
2571 dm_bio_prison_destroy(pool->prison);
2575 if (dm_pool_metadata_close(pmd))
2576 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2581 static void __pool_inc(struct pool *pool)
2583 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2587 static void __pool_dec(struct pool *pool)
2589 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2590 BUG_ON(!pool->ref_count);
2591 if (!--pool->ref_count)
2592 __pool_destroy(pool);
2595 static struct pool *__pool_find(struct mapped_device *pool_md,
2596 struct block_device *metadata_dev,
2597 unsigned long block_size, int read_only,
2598 char **error, int *created)
2600 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
2603 if (pool->pool_md != pool_md) {
2604 *error = "metadata device already in use by a pool";
2605 return ERR_PTR(-EBUSY);
2610 pool = __pool_table_lookup(pool_md);
2612 if (pool->md_dev != metadata_dev) {
2613 *error = "different pool cannot replace a pool";
2614 return ERR_PTR(-EINVAL);
2619 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
2627 /*----------------------------------------------------------------
2628 * Pool target methods
2629 *--------------------------------------------------------------*/
2630 static void pool_dtr(struct dm_target *ti)
2632 struct pool_c *pt = ti->private;
2634 mutex_lock(&dm_thin_pool_table.mutex);
2636 unbind_control_target(pt->pool, ti);
2637 __pool_dec(pt->pool);
2638 dm_put_device(ti, pt->metadata_dev);
2639 dm_put_device(ti, pt->data_dev);
2642 mutex_unlock(&dm_thin_pool_table.mutex);
2645 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
2646 struct dm_target *ti)
2650 const char *arg_name;
2652 static struct dm_arg _args[] = {
2653 {0, 4, "Invalid number of pool feature arguments"},
2657 * No feature arguments supplied.
2662 r = dm_read_arg_group(_args, as, &argc, &ti->error);
2666 while (argc && !r) {
2667 arg_name = dm_shift_arg(as);
2670 if (!strcasecmp(arg_name, "skip_block_zeroing"))
2671 pf->zero_new_blocks = false;
2673 else if (!strcasecmp(arg_name, "ignore_discard"))
2674 pf->discard_enabled = false;
2676 else if (!strcasecmp(arg_name, "no_discard_passdown"))
2677 pf->discard_passdown = false;
2679 else if (!strcasecmp(arg_name, "read_only"))
2680 pf->mode = PM_READ_ONLY;
2682 else if (!strcasecmp(arg_name, "error_if_no_space"))
2683 pf->error_if_no_space = true;
2686 ti->error = "Unrecognised pool feature requested";
2695 static void metadata_low_callback(void *context)
2697 struct pool *pool = context;
2699 DMWARN("%s: reached low water mark for metadata device: sending event.",
2700 dm_device_name(pool->pool_md));
2702 dm_table_event(pool->ti->table);
2705 static sector_t get_dev_size(struct block_device *bdev)
2707 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
2710 static void warn_if_metadata_device_too_big(struct block_device *bdev)
2712 sector_t metadata_dev_size = get_dev_size(bdev);
2713 char buffer[BDEVNAME_SIZE];
2715 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
2716 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
2717 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
2720 static sector_t get_metadata_dev_size(struct block_device *bdev)
2722 sector_t metadata_dev_size = get_dev_size(bdev);
2724 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
2725 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
2727 return metadata_dev_size;
2730 static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
2732 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
2734 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
2736 return metadata_dev_size;
2740 * When a metadata threshold is crossed a dm event is triggered, and
2741 * userland should respond by growing the metadata device. We could let
2742 * userland set the threshold, like we do with the data threshold, but I'm
2743 * not sure they know enough to do this well.
2745 static dm_block_t calc_metadata_threshold(struct pool_c *pt)
2748 * 4M is ample for all ops with the possible exception of thin
2749 * device deletion which is harmless if it fails (just retry the
2750 * delete after you've grown the device).
2752 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
2753 return min((dm_block_t)1024ULL /* 4M */, quarter);
2757 * thin-pool <metadata dev> <data dev>
2758 * <data block size (sectors)>
2759 * <low water mark (blocks)>
2760 * [<#feature args> [<arg>]*]
2762 * Optional feature arguments are:
2763 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
2764 * ignore_discard: disable discard
2765 * no_discard_passdown: don't pass discards down to the data device
2766 * read_only: Don't allow any changes to be made to the pool metadata.
2767 * error_if_no_space: error IOs, instead of queueing, if no space.
2769 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
2771 int r, pool_created = 0;
2774 struct pool_features pf;
2775 struct dm_arg_set as;
2776 struct dm_dev *data_dev;
2777 unsigned long block_size;
2778 dm_block_t low_water_blocks;
2779 struct dm_dev *metadata_dev;
2780 fmode_t metadata_mode;
2783 * FIXME Remove validation from scope of lock.
2785 mutex_lock(&dm_thin_pool_table.mutex);
2788 ti->error = "Invalid argument count";
2797 * Set default pool features.
2799 pool_features_init(&pf);
2801 dm_consume_args(&as, 4);
2802 r = parse_pool_features(&as, &pf, ti);
2806 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
2807 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
2809 ti->error = "Error opening metadata block device";
2812 warn_if_metadata_device_too_big(metadata_dev->bdev);
2814 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
2816 ti->error = "Error getting data device";
2820 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
2821 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
2822 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
2823 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
2824 ti->error = "Invalid block size";
2829 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
2830 ti->error = "Invalid low water mark";
2835 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
2841 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
2842 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
2849 * 'pool_created' reflects whether this is the first table load.
2850 * Top level discard support is not allowed to be changed after
2851 * initial load. This would require a pool reload to trigger thin
2854 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
2855 ti->error = "Discard support cannot be disabled once enabled";
2857 goto out_flags_changed;
2862 pt->metadata_dev = metadata_dev;
2863 pt->data_dev = data_dev;
2864 pt->low_water_blocks = low_water_blocks;
2865 pt->adjusted_pf = pt->requested_pf = pf;
2866 ti->num_flush_bios = 1;
2869 * Only need to enable discards if the pool should pass
2870 * them down to the data device. The thin device's discard
2871 * processing will cause mappings to be removed from the btree.
2873 ti->discard_zeroes_data_unsupported = true;
2874 if (pf.discard_enabled && pf.discard_passdown) {
2875 ti->num_discard_bios = 1;
2878 * Setting 'discards_supported' circumvents the normal
2879 * stacking of discard limits (this keeps the pool and
2880 * thin devices' discard limits consistent).
2882 ti->discards_supported = true;
2886 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
2887 calc_metadata_threshold(pt),
2888 metadata_low_callback,
2893 pt->callbacks.congested_fn = pool_is_congested;
2894 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2896 mutex_unlock(&dm_thin_pool_table.mutex);
2905 dm_put_device(ti, data_dev);
2907 dm_put_device(ti, metadata_dev);
2909 mutex_unlock(&dm_thin_pool_table.mutex);
2914 static int pool_map(struct dm_target *ti, struct bio *bio)
2917 struct pool_c *pt = ti->private;
2918 struct pool *pool = pt->pool;
2919 unsigned long flags;
2922 * As this is a singleton target, ti->begin is always zero.
2924 spin_lock_irqsave(&pool->lock, flags);
2925 bio->bi_bdev = pt->data_dev->bdev;
2926 r = DM_MAPIO_REMAPPED;
2927 spin_unlock_irqrestore(&pool->lock, flags);
2932 static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
2935 struct pool_c *pt = ti->private;
2936 struct pool *pool = pt->pool;
2937 sector_t data_size = ti->len;
2938 dm_block_t sb_data_size;
2940 *need_commit = false;
2942 (void) sector_div(data_size, pool->sectors_per_block);
2944 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2946 DMERR("%s: failed to retrieve data device size",
2947 dm_device_name(pool->pool_md));
2951 if (data_size < sb_data_size) {
2952 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
2953 dm_device_name(pool->pool_md),
2954 (unsigned long long)data_size, sb_data_size);
2957 } else if (data_size > sb_data_size) {
2958 if (dm_pool_metadata_needs_check(pool->pmd)) {
2959 DMERR("%s: unable to grow the data device until repaired.",
2960 dm_device_name(pool->pool_md));
2965 DMINFO("%s: growing the data device from %llu to %llu blocks",
2966 dm_device_name(pool->pool_md),
2967 sb_data_size, (unsigned long long)data_size);
2968 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2970 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
2974 *need_commit = true;
2980 static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
2983 struct pool_c *pt = ti->private;
2984 struct pool *pool = pt->pool;
2985 dm_block_t metadata_dev_size, sb_metadata_dev_size;
2987 *need_commit = false;
2989 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
2991 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
2993 DMERR("%s: failed to retrieve metadata device size",
2994 dm_device_name(pool->pool_md));
2998 if (metadata_dev_size < sb_metadata_dev_size) {
2999 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
3000 dm_device_name(pool->pool_md),
3001 metadata_dev_size, sb_metadata_dev_size);
3004 } else if (metadata_dev_size > sb_metadata_dev_size) {
3005 if (dm_pool_metadata_needs_check(pool->pmd)) {
3006 DMERR("%s: unable to grow the metadata device until repaired.",
3007 dm_device_name(pool->pool_md));
3011 warn_if_metadata_device_too_big(pool->md_dev);
3012 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
3013 dm_device_name(pool->pool_md),
3014 sb_metadata_dev_size, metadata_dev_size);
3015 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
3017 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
3021 *need_commit = true;
3028 * Retrieves the number of blocks of the data device from
3029 * the superblock and compares it to the actual device size,
3030 * thus resizing the data device in case it has grown.
3032 * This both copes with opening preallocated data devices in the ctr
3033 * being followed by a resume
3035 * calling the resume method individually after userspace has
3036 * grown the data device in reaction to a table event.
3038 static int pool_preresume(struct dm_target *ti)
3041 bool need_commit1, need_commit2;
3042 struct pool_c *pt = ti->private;
3043 struct pool *pool = pt->pool;
3046 * Take control of the pool object.
3048 r = bind_control_target(pool, ti);
3052 r = maybe_resize_data_dev(ti, &need_commit1);
3056 r = maybe_resize_metadata_dev(ti, &need_commit2);
3060 if (need_commit1 || need_commit2)
3061 (void) commit(pool);
3066 static void pool_resume(struct dm_target *ti)
3068 struct pool_c *pt = ti->private;
3069 struct pool *pool = pt->pool;
3070 unsigned long flags;
3072 spin_lock_irqsave(&pool->lock, flags);
3073 pool->low_water_triggered = false;
3074 spin_unlock_irqrestore(&pool->lock, flags);
3077 do_waker(&pool->waker.work);
3080 static void pool_postsuspend(struct dm_target *ti)
3082 struct pool_c *pt = ti->private;
3083 struct pool *pool = pt->pool;
3085 cancel_delayed_work(&pool->waker);
3086 cancel_delayed_work(&pool->no_space_timeout);
3087 flush_workqueue(pool->wq);
3088 (void) commit(pool);
3091 static int check_arg_count(unsigned argc, unsigned args_required)
3093 if (argc != args_required) {
3094 DMWARN("Message received with %u arguments instead of %u.",
3095 argc, args_required);
3102 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
3104 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
3105 *dev_id <= MAX_DEV_ID)
3109 DMWARN("Message received with invalid device id: %s", arg);
3114 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
3119 r = check_arg_count(argc, 2);
3123 r = read_dev_id(argv[1], &dev_id, 1);
3127 r = dm_pool_create_thin(pool->pmd, dev_id);
3129 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
3137 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3140 dm_thin_id origin_dev_id;
3143 r = check_arg_count(argc, 3);
3147 r = read_dev_id(argv[1], &dev_id, 1);
3151 r = read_dev_id(argv[2], &origin_dev_id, 1);
3155 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
3157 DMWARN("Creation of new snapshot %s of device %s failed.",
3165 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
3170 r = check_arg_count(argc, 2);
3174 r = read_dev_id(argv[1], &dev_id, 1);
3178 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
3180 DMWARN("Deletion of thin device %s failed.", argv[1]);
3185 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
3187 dm_thin_id old_id, new_id;
3190 r = check_arg_count(argc, 3);
3194 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
3195 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
3199 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
3200 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
3204 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
3206 DMWARN("Failed to change transaction id from %s to %s.",
3214 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3218 r = check_arg_count(argc, 1);
3222 (void) commit(pool);
3224 r = dm_pool_reserve_metadata_snap(pool->pmd);
3226 DMWARN("reserve_metadata_snap message failed.");
3231 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3235 r = check_arg_count(argc, 1);
3239 r = dm_pool_release_metadata_snap(pool->pmd);
3241 DMWARN("release_metadata_snap message failed.");
3247 * Messages supported:
3248 * create_thin <dev_id>
3249 * create_snap <dev_id> <origin_id>
3251 * trim <dev_id> <new_size_in_sectors>
3252 * set_transaction_id <current_trans_id> <new_trans_id>
3253 * reserve_metadata_snap
3254 * release_metadata_snap
3256 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
3259 struct pool_c *pt = ti->private;
3260 struct pool *pool = pt->pool;
3262 if (!strcasecmp(argv[0], "create_thin"))
3263 r = process_create_thin_mesg(argc, argv, pool);
3265 else if (!strcasecmp(argv[0], "create_snap"))
3266 r = process_create_snap_mesg(argc, argv, pool);
3268 else if (!strcasecmp(argv[0], "delete"))
3269 r = process_delete_mesg(argc, argv, pool);
3271 else if (!strcasecmp(argv[0], "set_transaction_id"))
3272 r = process_set_transaction_id_mesg(argc, argv, pool);
3274 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
3275 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
3277 else if (!strcasecmp(argv[0], "release_metadata_snap"))
3278 r = process_release_metadata_snap_mesg(argc, argv, pool);
3281 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
3284 (void) commit(pool);
3289 static void emit_flags(struct pool_features *pf, char *result,
3290 unsigned sz, unsigned maxlen)
3292 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
3293 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
3294 pf->error_if_no_space;
3295 DMEMIT("%u ", count);
3297 if (!pf->zero_new_blocks)
3298 DMEMIT("skip_block_zeroing ");
3300 if (!pf->discard_enabled)
3301 DMEMIT("ignore_discard ");
3303 if (!pf->discard_passdown)
3304 DMEMIT("no_discard_passdown ");
3306 if (pf->mode == PM_READ_ONLY)
3307 DMEMIT("read_only ");
3309 if (pf->error_if_no_space)
3310 DMEMIT("error_if_no_space ");
3315 * <transaction id> <used metadata sectors>/<total metadata sectors>
3316 * <used data sectors>/<total data sectors> <held metadata root>
3318 static void pool_status(struct dm_target *ti, status_type_t type,
3319 unsigned status_flags, char *result, unsigned maxlen)
3323 uint64_t transaction_id;
3324 dm_block_t nr_free_blocks_data;
3325 dm_block_t nr_free_blocks_metadata;
3326 dm_block_t nr_blocks_data;
3327 dm_block_t nr_blocks_metadata;
3328 dm_block_t held_root;
3329 char buf[BDEVNAME_SIZE];
3330 char buf2[BDEVNAME_SIZE];
3331 struct pool_c *pt = ti->private;
3332 struct pool *pool = pt->pool;
3335 case STATUSTYPE_INFO:
3336 if (get_pool_mode(pool) == PM_FAIL) {
3341 /* Commit to ensure statistics aren't out-of-date */
3342 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3343 (void) commit(pool);
3345 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
3347 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
3348 dm_device_name(pool->pool_md), r);
3352 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
3354 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
3355 dm_device_name(pool->pool_md), r);
3359 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
3361 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
3362 dm_device_name(pool->pool_md), r);
3366 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
3368 DMERR("%s: dm_pool_get_free_block_count returned %d",
3369 dm_device_name(pool->pool_md), r);
3373 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
3375 DMERR("%s: dm_pool_get_data_dev_size returned %d",
3376 dm_device_name(pool->pool_md), r);
3380 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
3382 DMERR("%s: dm_pool_get_metadata_snap returned %d",
3383 dm_device_name(pool->pool_md), r);
3387 DMEMIT("%llu %llu/%llu %llu/%llu ",
3388 (unsigned long long)transaction_id,
3389 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3390 (unsigned long long)nr_blocks_metadata,
3391 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
3392 (unsigned long long)nr_blocks_data);
3395 DMEMIT("%llu ", held_root);
3399 if (pool->pf.mode == PM_OUT_OF_DATA_SPACE)
3400 DMEMIT("out_of_data_space ");
3401 else if (pool->pf.mode == PM_READ_ONLY)
3406 if (!pool->pf.discard_enabled)
3407 DMEMIT("ignore_discard ");
3408 else if (pool->pf.discard_passdown)
3409 DMEMIT("discard_passdown ");
3411 DMEMIT("no_discard_passdown ");
3413 if (pool->pf.error_if_no_space)
3414 DMEMIT("error_if_no_space ");
3416 DMEMIT("queue_if_no_space ");
3420 case STATUSTYPE_TABLE:
3421 DMEMIT("%s %s %lu %llu ",
3422 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
3423 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
3424 (unsigned long)pool->sectors_per_block,
3425 (unsigned long long)pt->low_water_blocks);
3426 emit_flags(&pt->requested_pf, result, sz, maxlen);
3435 static int pool_iterate_devices(struct dm_target *ti,
3436 iterate_devices_callout_fn fn, void *data)
3438 struct pool_c *pt = ti->private;
3440 return fn(ti, pt->data_dev, 0, ti->len, data);
3443 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
3444 struct bio_vec *biovec, int max_size)
3446 struct pool_c *pt = ti->private;
3447 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
3449 if (!q->merge_bvec_fn)
3452 bvm->bi_bdev = pt->data_dev->bdev;
3454 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3457 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
3459 struct pool *pool = pt->pool;
3460 struct queue_limits *data_limits;
3462 limits->max_discard_sectors = pool->sectors_per_block;
3465 * discard_granularity is just a hint, and not enforced.
3467 if (pt->adjusted_pf.discard_passdown) {
3468 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
3469 limits->discard_granularity = max(data_limits->discard_granularity,
3470 pool->sectors_per_block << SECTOR_SHIFT);
3472 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
3475 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
3477 struct pool_c *pt = ti->private;
3478 struct pool *pool = pt->pool;
3479 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
3482 * Adjust max_sectors_kb to highest possible power-of-2
3483 * factor of pool->sectors_per_block.
3485 if (limits->max_hw_sectors & (limits->max_hw_sectors - 1))
3486 limits->max_sectors = rounddown_pow_of_two(limits->max_hw_sectors);
3488 limits->max_sectors = limits->max_hw_sectors;
3490 if (limits->max_sectors < pool->sectors_per_block) {
3491 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
3492 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
3493 limits->max_sectors--;
3494 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
3496 } else if (block_size_is_power_of_two(pool)) {
3497 /* max_sectors_kb is >= power-of-2 thinp blocksize */
3498 while (!is_factor(limits->max_sectors, pool->sectors_per_block)) {
3499 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
3500 limits->max_sectors--;
3501 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
3506 * If the system-determined stacked limits are compatible with the
3507 * pool's blocksize (io_opt is a factor) do not override them.
3509 if (io_opt_sectors < pool->sectors_per_block ||
3510 !is_factor(io_opt_sectors, pool->sectors_per_block)) {
3511 if (is_factor(pool->sectors_per_block, limits->max_sectors))
3512 blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT);
3514 blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);
3515 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
3519 * pt->adjusted_pf is a staging area for the actual features to use.
3520 * They get transferred to the live pool in bind_control_target()
3521 * called from pool_preresume().
3523 if (!pt->adjusted_pf.discard_enabled) {
3525 * Must explicitly disallow stacking discard limits otherwise the
3526 * block layer will stack them if pool's data device has support.
3527 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
3528 * user to see that, so make sure to set all discard limits to 0.
3530 limits->discard_granularity = 0;
3534 disable_passdown_if_not_supported(pt);
3536 set_discard_limits(pt, limits);
3539 static struct target_type pool_target = {
3540 .name = "thin-pool",
3541 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
3542 DM_TARGET_IMMUTABLE,
3543 .version = {1, 14, 0},
3544 .module = THIS_MODULE,
3548 .postsuspend = pool_postsuspend,
3549 .preresume = pool_preresume,
3550 .resume = pool_resume,
3551 .message = pool_message,
3552 .status = pool_status,
3553 .merge = pool_merge,
3554 .iterate_devices = pool_iterate_devices,
3555 .io_hints = pool_io_hints,
3558 /*----------------------------------------------------------------
3559 * Thin target methods
3560 *--------------------------------------------------------------*/
3561 static void thin_get(struct thin_c *tc)
3563 atomic_inc(&tc->refcount);
3566 static void thin_put(struct thin_c *tc)
3568 if (atomic_dec_and_test(&tc->refcount))
3569 complete(&tc->can_destroy);
3572 static void thin_dtr(struct dm_target *ti)
3574 struct thin_c *tc = ti->private;
3575 unsigned long flags;
3578 wait_for_completion(&tc->can_destroy);
3580 spin_lock_irqsave(&tc->pool->lock, flags);
3581 list_del_rcu(&tc->list);
3582 spin_unlock_irqrestore(&tc->pool->lock, flags);
3585 mutex_lock(&dm_thin_pool_table.mutex);
3587 __pool_dec(tc->pool);
3588 dm_pool_close_thin_device(tc->td);
3589 dm_put_device(ti, tc->pool_dev);
3591 dm_put_device(ti, tc->origin_dev);
3594 mutex_unlock(&dm_thin_pool_table.mutex);
3598 * Thin target parameters:
3600 * <pool_dev> <dev_id> [origin_dev]
3602 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
3603 * dev_id: the internal device identifier
3604 * origin_dev: a device external to the pool that should act as the origin
3606 * If the pool device has discards disabled, they get disabled for the thin
3609 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
3613 struct dm_dev *pool_dev, *origin_dev;
3614 struct mapped_device *pool_md;
3615 unsigned long flags;
3617 mutex_lock(&dm_thin_pool_table.mutex);
3619 if (argc != 2 && argc != 3) {
3620 ti->error = "Invalid argument count";
3625 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
3627 ti->error = "Out of memory";
3631 spin_lock_init(&tc->lock);
3632 INIT_LIST_HEAD(&tc->deferred_cells);
3633 bio_list_init(&tc->deferred_bio_list);
3634 bio_list_init(&tc->retry_on_resume_list);
3635 tc->sort_bio_list = RB_ROOT;
3638 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
3640 ti->error = "Error opening origin device";
3641 goto bad_origin_dev;
3643 tc->origin_dev = origin_dev;
3646 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
3648 ti->error = "Error opening pool device";
3651 tc->pool_dev = pool_dev;
3653 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
3654 ti->error = "Invalid device id";
3659 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
3661 ti->error = "Couldn't get pool mapped device";
3666 tc->pool = __pool_table_lookup(pool_md);
3668 ti->error = "Couldn't find pool object";
3670 goto bad_pool_lookup;
3672 __pool_inc(tc->pool);
3674 if (get_pool_mode(tc->pool) == PM_FAIL) {
3675 ti->error = "Couldn't open thin device, Pool is in fail mode";
3680 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
3682 ti->error = "Couldn't open thin internal device";
3686 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
3688 goto bad_target_max_io_len;
3690 ti->num_flush_bios = 1;
3691 ti->flush_supported = true;
3692 ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
3694 /* In case the pool supports discards, pass them on. */
3695 ti->discard_zeroes_data_unsupported = true;
3696 if (tc->pool->pf.discard_enabled) {
3697 ti->discards_supported = true;
3698 ti->num_discard_bios = 1;
3699 /* Discard bios must be split on a block boundary */
3700 ti->split_discard_bios = true;
3705 mutex_unlock(&dm_thin_pool_table.mutex);
3707 atomic_set(&tc->refcount, 1);
3708 init_completion(&tc->can_destroy);
3710 spin_lock_irqsave(&tc->pool->lock, flags);
3711 list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
3712 spin_unlock_irqrestore(&tc->pool->lock, flags);
3714 * This synchronize_rcu() call is needed here otherwise we risk a
3715 * wake_worker() call finding no bios to process (because the newly
3716 * added tc isn't yet visible). So this reduces latency since we
3717 * aren't then dependent on the periodic commit to wake_worker().
3723 bad_target_max_io_len:
3724 dm_pool_close_thin_device(tc->td);
3726 __pool_dec(tc->pool);
3730 dm_put_device(ti, tc->pool_dev);
3733 dm_put_device(ti, tc->origin_dev);
3737 mutex_unlock(&dm_thin_pool_table.mutex);
3742 static int thin_map(struct dm_target *ti, struct bio *bio)
3744 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
3746 return thin_bio_map(ti, bio);
3749 static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
3751 unsigned long flags;
3752 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
3753 struct list_head work;
3754 struct dm_thin_new_mapping *m, *tmp;
3755 struct pool *pool = h->tc->pool;
3757 if (h->shared_read_entry) {
3758 INIT_LIST_HEAD(&work);
3759 dm_deferred_entry_dec(h->shared_read_entry, &work);
3761 spin_lock_irqsave(&pool->lock, flags);
3762 list_for_each_entry_safe(m, tmp, &work, list) {
3764 __complete_mapping_preparation(m);
3766 spin_unlock_irqrestore(&pool->lock, flags);
3769 if (h->all_io_entry) {
3770 INIT_LIST_HEAD(&work);
3771 dm_deferred_entry_dec(h->all_io_entry, &work);
3772 if (!list_empty(&work)) {
3773 spin_lock_irqsave(&pool->lock, flags);
3774 list_for_each_entry_safe(m, tmp, &work, list)
3775 list_add_tail(&m->list, &pool->prepared_discards);
3776 spin_unlock_irqrestore(&pool->lock, flags);
3784 static void thin_presuspend(struct dm_target *ti)
3786 struct thin_c *tc = ti->private;
3788 if (dm_noflush_suspending(ti))
3789 noflush_work(tc, do_noflush_start);
3792 static void thin_postsuspend(struct dm_target *ti)
3794 struct thin_c *tc = ti->private;
3797 * The dm_noflush_suspending flag has been cleared by now, so
3798 * unfortunately we must always run this.
3800 noflush_work(tc, do_noflush_stop);
3803 static int thin_preresume(struct dm_target *ti)
3805 struct thin_c *tc = ti->private;
3808 tc->origin_size = get_dev_size(tc->origin_dev->bdev);
3814 * <nr mapped sectors> <highest mapped sector>
3816 static void thin_status(struct dm_target *ti, status_type_t type,
3817 unsigned status_flags, char *result, unsigned maxlen)
3821 dm_block_t mapped, highest;
3822 char buf[BDEVNAME_SIZE];
3823 struct thin_c *tc = ti->private;
3825 if (get_pool_mode(tc->pool) == PM_FAIL) {
3834 case STATUSTYPE_INFO:
3835 r = dm_thin_get_mapped_count(tc->td, &mapped);
3837 DMERR("dm_thin_get_mapped_count returned %d", r);
3841 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
3843 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
3847 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
3849 DMEMIT("%llu", ((highest + 1) *
3850 tc->pool->sectors_per_block) - 1);
3855 case STATUSTYPE_TABLE:
3857 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
3858 (unsigned long) tc->dev_id);
3860 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
3871 static int thin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
3872 struct bio_vec *biovec, int max_size)
3874 struct thin_c *tc = ti->private;
3875 struct request_queue *q = bdev_get_queue(tc->pool_dev->bdev);
3877 if (!q->merge_bvec_fn)
3880 bvm->bi_bdev = tc->pool_dev->bdev;
3881 bvm->bi_sector = dm_target_offset(ti, bvm->bi_sector);
3883 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3886 static int thin_iterate_devices(struct dm_target *ti,
3887 iterate_devices_callout_fn fn, void *data)
3890 struct thin_c *tc = ti->private;
3891 struct pool *pool = tc->pool;
3894 * We can't call dm_pool_get_data_dev_size() since that blocks. So
3895 * we follow a more convoluted path through to the pool's target.
3898 return 0; /* nothing is bound */
3900 blocks = pool->ti->len;
3901 (void) sector_div(blocks, pool->sectors_per_block);
3903 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
3908 static struct target_type thin_target = {
3910 .version = {1, 14, 0},
3911 .module = THIS_MODULE,
3915 .end_io = thin_endio,
3916 .preresume = thin_preresume,
3917 .presuspend = thin_presuspend,
3918 .postsuspend = thin_postsuspend,
3919 .status = thin_status,
3920 .merge = thin_merge,
3921 .iterate_devices = thin_iterate_devices,
3924 /*----------------------------------------------------------------*/
3926 static int __init dm_thin_init(void)
3932 r = dm_register_target(&thin_target);
3936 r = dm_register_target(&pool_target);
3938 goto bad_pool_target;
3942 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
3943 if (!_new_mapping_cache)
3944 goto bad_new_mapping_cache;
3948 bad_new_mapping_cache:
3949 dm_unregister_target(&pool_target);
3951 dm_unregister_target(&thin_target);
3956 static void dm_thin_exit(void)
3958 dm_unregister_target(&thin_target);
3959 dm_unregister_target(&pool_target);
3961 kmem_cache_destroy(_new_mapping_cache);
3964 module_init(dm_thin_init);
3965 module_exit(dm_thin_exit);
3967 module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);
3968 MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
3970 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
3971 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3972 MODULE_LICENSE("GPL");