2 * Copyright (C) 2011-2012 Red Hat UK.
4 * This file is released under the GPL.
7 #include "dm-thin-metadata.h"
8 #include "dm-bio-prison.h"
11 #include <linux/device-mapper.h>
12 #include <linux/dm-io.h>
13 #include <linux/dm-kcopyd.h>
14 #include <linux/list.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
19 #define DM_MSG_PREFIX "thin"
24 #define ENDIO_HOOK_POOL_SIZE 1024
25 #define MAPPING_POOL_SIZE 1024
26 #define PRISON_CELLS 1024
27 #define COMMIT_PERIOD HZ
29 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
30 "A percentage of time allocated for copy on write");
33 * The block size of the device holding pool data must be
34 * between 64KB and 1GB.
36 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
37 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
40 * Device id is restricted to 24 bits.
42 #define MAX_DEV_ID ((1 << 24) - 1)
45 * How do we handle breaking sharing of data blocks?
46 * =================================================
48 * We use a standard copy-on-write btree to store the mappings for the
49 * devices (note I'm talking about copy-on-write of the metadata here, not
50 * the data). When you take an internal snapshot you clone the root node
51 * of the origin btree. After this there is no concept of an origin or a
52 * snapshot. They are just two device trees that happen to point to the
55 * When we get a write in we decide if it's to a shared data block using
56 * some timestamp magic. If it is, we have to break sharing.
58 * Let's say we write to a shared block in what was the origin. The
61 * i) plug io further to this physical block. (see bio_prison code).
63 * ii) quiesce any read io to that shared data block. Obviously
64 * including all devices that share this block. (see dm_deferred_set code)
66 * iii) copy the data block to a newly allocate block. This step can be
67 * missed out if the io covers the block. (schedule_copy).
69 * iv) insert the new mapping into the origin's btree
70 * (process_prepared_mapping). This act of inserting breaks some
71 * sharing of btree nodes between the two devices. Breaking sharing only
72 * effects the btree of that specific device. Btrees for the other
73 * devices that share the block never change. The btree for the origin
74 * device as it was after the last commit is untouched, ie. we're using
75 * persistent data structures in the functional programming sense.
77 * v) unplug io to this physical block, including the io that triggered
78 * the breaking of sharing.
80 * Steps (ii) and (iii) occur in parallel.
82 * The metadata _doesn't_ need to be committed before the io continues. We
83 * get away with this because the io is always written to a _new_ block.
84 * If there's a crash, then:
86 * - The origin mapping will point to the old origin block (the shared
87 * one). This will contain the data as it was before the io that triggered
88 * the breaking of sharing came in.
90 * - The snap mapping still points to the old block. As it would after
93 * The downside of this scheme is the timestamp magic isn't perfect, and
94 * will continue to think that data block in the snapshot device is shared
95 * even after the write to the origin has broken sharing. I suspect data
96 * blocks will typically be shared by many different devices, so we're
97 * breaking sharing n + 1 times, rather than n, where n is the number of
98 * devices that reference this data block. At the moment I think the
99 * benefits far, far outweigh the disadvantages.
102 /*----------------------------------------------------------------*/
107 static void build_data_key(struct dm_thin_device *td,
108 dm_block_t b, struct dm_cell_key *key)
111 key->dev = dm_thin_dev_id(td);
115 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
116 struct dm_cell_key *key)
119 key->dev = dm_thin_dev_id(td);
123 /*----------------------------------------------------------------*/
126 * A pool device ties together a metadata device and a data device. It
127 * also provides the interface for creating and destroying internal
130 struct dm_thin_new_mapping;
133 * The pool runs in 4 modes. Ordered in degraded order for comparisons.
136 PM_WRITE, /* metadata may be changed */
137 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
138 PM_READ_ONLY, /* metadata may not be changed */
139 PM_FAIL, /* all I/O fails */
142 struct pool_features {
145 bool zero_new_blocks:1;
146 bool discard_enabled:1;
147 bool discard_passdown:1;
148 bool error_if_no_space:1;
152 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
153 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
156 struct list_head list;
157 struct dm_target *ti; /* Only set if a pool target is bound */
159 struct mapped_device *pool_md;
160 struct block_device *md_dev;
161 struct dm_pool_metadata *pmd;
163 dm_block_t low_water_blocks;
164 uint32_t sectors_per_block;
165 int sectors_per_block_shift;
167 struct pool_features pf;
168 bool low_water_triggered:1; /* A dm event has been sent */
170 struct dm_bio_prison *prison;
171 struct dm_kcopyd_client *copier;
173 struct workqueue_struct *wq;
174 struct work_struct worker;
175 struct delayed_work waker;
177 unsigned long last_commit_jiffies;
181 struct bio_list deferred_bios;
182 struct bio_list deferred_flush_bios;
183 struct list_head prepared_mappings;
184 struct list_head prepared_discards;
186 struct bio_list retry_on_resume_list;
188 struct dm_deferred_set *shared_read_ds;
189 struct dm_deferred_set *all_io_ds;
191 struct dm_thin_new_mapping *next_mapping;
192 mempool_t *mapping_pool;
194 process_bio_fn process_bio;
195 process_bio_fn process_discard;
197 process_mapping_fn process_prepared_mapping;
198 process_mapping_fn process_prepared_discard;
201 static enum pool_mode get_pool_mode(struct pool *pool);
202 static void metadata_operation_failed(struct pool *pool, const char *op, int r);
205 * Target context for a pool.
208 struct dm_target *ti;
210 struct dm_dev *data_dev;
211 struct dm_dev *metadata_dev;
212 struct dm_target_callbacks callbacks;
214 dm_block_t low_water_blocks;
215 struct pool_features requested_pf; /* Features requested during table load */
216 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
220 * Target context for a thin.
223 struct dm_dev *pool_dev;
224 struct dm_dev *origin_dev;
228 struct dm_thin_device *td;
231 /*----------------------------------------------------------------*/
234 * wake_worker() is used when new work is queued and when pool_resume is
235 * ready to continue deferred IO processing.
237 static void wake_worker(struct pool *pool)
239 queue_work(pool->wq, &pool->worker);
242 /*----------------------------------------------------------------*/
244 static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
245 struct dm_bio_prison_cell **cell_result)
248 struct dm_bio_prison_cell *cell_prealloc;
251 * Allocate a cell from the prison's mempool.
252 * This might block but it can't fail.
254 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
256 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
259 * We reused an old cell; we can get rid of
262 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
267 static void cell_release(struct pool *pool,
268 struct dm_bio_prison_cell *cell,
269 struct bio_list *bios)
271 dm_cell_release(pool->prison, cell, bios);
272 dm_bio_prison_free_cell(pool->prison, cell);
275 static void cell_release_no_holder(struct pool *pool,
276 struct dm_bio_prison_cell *cell,
277 struct bio_list *bios)
279 dm_cell_release_no_holder(pool->prison, cell, bios);
280 dm_bio_prison_free_cell(pool->prison, cell);
283 static void cell_defer_no_holder_no_free(struct thin_c *tc,
284 struct dm_bio_prison_cell *cell)
286 struct pool *pool = tc->pool;
289 spin_lock_irqsave(&pool->lock, flags);
290 dm_cell_release_no_holder(pool->prison, cell, &pool->deferred_bios);
291 spin_unlock_irqrestore(&pool->lock, flags);
296 static void cell_error(struct pool *pool,
297 struct dm_bio_prison_cell *cell)
299 dm_cell_error(pool->prison, cell);
300 dm_bio_prison_free_cell(pool->prison, cell);
303 /*----------------------------------------------------------------*/
306 * A global list of pools that uses a struct mapped_device as a key.
308 static struct dm_thin_pool_table {
310 struct list_head pools;
311 } dm_thin_pool_table;
313 static void pool_table_init(void)
315 mutex_init(&dm_thin_pool_table.mutex);
316 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
319 static void __pool_table_insert(struct pool *pool)
321 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
322 list_add(&pool->list, &dm_thin_pool_table.pools);
325 static void __pool_table_remove(struct pool *pool)
327 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
328 list_del(&pool->list);
331 static struct pool *__pool_table_lookup(struct mapped_device *md)
333 struct pool *pool = NULL, *tmp;
335 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
337 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
338 if (tmp->pool_md == md) {
347 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
349 struct pool *pool = NULL, *tmp;
351 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
353 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
354 if (tmp->md_dev == md_dev) {
363 /*----------------------------------------------------------------*/
365 struct dm_thin_endio_hook {
367 struct dm_deferred_entry *shared_read_entry;
368 struct dm_deferred_entry *all_io_entry;
369 struct dm_thin_new_mapping *overwrite_mapping;
372 static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
375 struct bio_list bios;
377 bio_list_init(&bios);
378 bio_list_merge(&bios, master);
379 bio_list_init(master);
381 while ((bio = bio_list_pop(&bios))) {
382 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
385 bio_endio(bio, DM_ENDIO_REQUEUE);
387 bio_list_add(master, bio);
391 static void requeue_io(struct thin_c *tc)
393 struct pool *pool = tc->pool;
396 spin_lock_irqsave(&pool->lock, flags);
397 __requeue_bio_list(tc, &pool->deferred_bios);
398 __requeue_bio_list(tc, &pool->retry_on_resume_list);
399 spin_unlock_irqrestore(&pool->lock, flags);
402 static void error_retry_list(struct pool *pool)
406 struct bio_list bios;
408 bio_list_init(&bios);
410 spin_lock_irqsave(&pool->lock, flags);
411 bio_list_merge(&bios, &pool->retry_on_resume_list);
412 bio_list_init(&pool->retry_on_resume_list);
413 spin_unlock_irqrestore(&pool->lock, flags);
415 while ((bio = bio_list_pop(&bios)))
420 * This section of code contains the logic for processing a thin device's IO.
421 * Much of the code depends on pool object resources (lists, workqueues, etc)
422 * but most is exclusively called from the thin target rather than the thin-pool
426 static bool block_size_is_power_of_two(struct pool *pool)
428 return pool->sectors_per_block_shift >= 0;
431 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
433 struct pool *pool = tc->pool;
434 sector_t block_nr = bio->bi_iter.bi_sector;
436 if (block_size_is_power_of_two(pool))
437 block_nr >>= pool->sectors_per_block_shift;
439 (void) sector_div(block_nr, pool->sectors_per_block);
444 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
446 struct pool *pool = tc->pool;
447 sector_t bi_sector = bio->bi_iter.bi_sector;
449 bio->bi_bdev = tc->pool_dev->bdev;
450 if (block_size_is_power_of_two(pool))
451 bio->bi_iter.bi_sector =
452 (block << pool->sectors_per_block_shift) |
453 (bi_sector & (pool->sectors_per_block - 1));
455 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
456 sector_div(bi_sector, pool->sectors_per_block);
459 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
461 bio->bi_bdev = tc->origin_dev->bdev;
464 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
466 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
467 dm_thin_changed_this_transaction(tc->td);
470 static void inc_all_io_entry(struct pool *pool, struct bio *bio)
472 struct dm_thin_endio_hook *h;
474 if (bio->bi_rw & REQ_DISCARD)
477 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
478 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
481 static void issue(struct thin_c *tc, struct bio *bio)
483 struct pool *pool = tc->pool;
486 if (!bio_triggers_commit(tc, bio)) {
487 generic_make_request(bio);
492 * Complete bio with an error if earlier I/O caused changes to
493 * the metadata that can't be committed e.g, due to I/O errors
494 * on the metadata device.
496 if (dm_thin_aborted_changes(tc->td)) {
502 * Batch together any bios that trigger commits and then issue a
503 * single commit for them in process_deferred_bios().
505 spin_lock_irqsave(&pool->lock, flags);
506 bio_list_add(&pool->deferred_flush_bios, bio);
507 spin_unlock_irqrestore(&pool->lock, flags);
510 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
512 remap_to_origin(tc, bio);
516 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
519 remap(tc, bio, block);
523 /*----------------------------------------------------------------*/
526 * Bio endio functions.
528 struct dm_thin_new_mapping {
529 struct list_head list;
534 bool definitely_not_shared:1;
538 dm_block_t virt_block;
539 dm_block_t data_block;
540 struct dm_bio_prison_cell *cell, *cell2;
543 * If the bio covers the whole area of a block then we can avoid
544 * zeroing or copying. Instead this bio is hooked. The bio will
545 * still be in the cell, so care has to be taken to avoid issuing
549 bio_end_io_t *saved_bi_end_io;
552 static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
554 struct pool *pool = m->tc->pool;
556 if (m->quiesced && m->prepared) {
557 list_add_tail(&m->list, &pool->prepared_mappings);
562 static void copy_complete(int read_err, unsigned long write_err, void *context)
565 struct dm_thin_new_mapping *m = context;
566 struct pool *pool = m->tc->pool;
568 m->err = read_err || write_err ? -EIO : 0;
570 spin_lock_irqsave(&pool->lock, flags);
572 __maybe_add_mapping(m);
573 spin_unlock_irqrestore(&pool->lock, flags);
576 static void overwrite_endio(struct bio *bio, int err)
579 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
580 struct dm_thin_new_mapping *m = h->overwrite_mapping;
581 struct pool *pool = m->tc->pool;
585 spin_lock_irqsave(&pool->lock, flags);
587 __maybe_add_mapping(m);
588 spin_unlock_irqrestore(&pool->lock, flags);
591 /*----------------------------------------------------------------*/
598 * Prepared mapping jobs.
602 * This sends the bios in the cell back to the deferred_bios list.
604 static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
606 struct pool *pool = tc->pool;
609 spin_lock_irqsave(&pool->lock, flags);
610 cell_release(pool, cell, &pool->deferred_bios);
611 spin_unlock_irqrestore(&tc->pool->lock, flags);
617 * Same as cell_defer above, except it omits the original holder of the cell.
619 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
621 struct pool *pool = tc->pool;
624 spin_lock_irqsave(&pool->lock, flags);
625 cell_release_no_holder(pool, cell, &pool->deferred_bios);
626 spin_unlock_irqrestore(&pool->lock, flags);
631 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
634 m->bio->bi_end_io = m->saved_bi_end_io;
635 atomic_inc(&m->bio->bi_remaining);
637 cell_error(m->tc->pool, m->cell);
639 mempool_free(m, m->tc->pool->mapping_pool);
642 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
644 struct thin_c *tc = m->tc;
645 struct pool *pool = tc->pool;
651 bio->bi_end_io = m->saved_bi_end_io;
652 atomic_inc(&bio->bi_remaining);
656 cell_error(pool, m->cell);
661 * Commit the prepared block into the mapping btree.
662 * Any I/O for this block arriving after this point will get
663 * remapped to it directly.
665 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
667 metadata_operation_failed(pool, "dm_thin_insert_block", r);
668 cell_error(pool, m->cell);
673 * Release any bios held while the block was being provisioned.
674 * If we are processing a write bio that completely covers the block,
675 * we already processed it so can ignore it now when processing
676 * the bios in the cell.
679 cell_defer_no_holder(tc, m->cell);
682 cell_defer(tc, m->cell);
686 mempool_free(m, pool->mapping_pool);
689 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
691 struct thin_c *tc = m->tc;
693 bio_io_error(m->bio);
694 cell_defer_no_holder(tc, m->cell);
695 cell_defer_no_holder(tc, m->cell2);
696 mempool_free(m, tc->pool->mapping_pool);
699 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
701 struct thin_c *tc = m->tc;
703 inc_all_io_entry(tc->pool, m->bio);
704 cell_defer_no_holder(tc, m->cell);
705 cell_defer_no_holder(tc, m->cell2);
708 if (m->definitely_not_shared)
709 remap_and_issue(tc, m->bio, m->data_block);
712 if (dm_pool_block_is_used(tc->pool->pmd, m->data_block, &used) || used)
713 bio_endio(m->bio, 0);
715 remap_and_issue(tc, m->bio, m->data_block);
718 bio_endio(m->bio, 0);
720 mempool_free(m, tc->pool->mapping_pool);
723 static void process_prepared_discard(struct dm_thin_new_mapping *m)
726 struct thin_c *tc = m->tc;
728 r = dm_thin_remove_block(tc->td, m->virt_block);
730 DMERR_LIMIT("dm_thin_remove_block() failed");
732 process_prepared_discard_passdown(m);
735 static void process_prepared(struct pool *pool, struct list_head *head,
736 process_mapping_fn *fn)
739 struct list_head maps;
740 struct dm_thin_new_mapping *m, *tmp;
742 INIT_LIST_HEAD(&maps);
743 spin_lock_irqsave(&pool->lock, flags);
744 list_splice_init(head, &maps);
745 spin_unlock_irqrestore(&pool->lock, flags);
747 list_for_each_entry_safe(m, tmp, &maps, list)
754 static int io_overlaps_block(struct pool *pool, struct bio *bio)
756 return bio->bi_iter.bi_size ==
757 (pool->sectors_per_block << SECTOR_SHIFT);
760 static int io_overwrites_block(struct pool *pool, struct bio *bio)
762 return (bio_data_dir(bio) == WRITE) &&
763 io_overlaps_block(pool, bio);
766 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
769 *save = bio->bi_end_io;
773 static int ensure_next_mapping(struct pool *pool)
775 if (pool->next_mapping)
778 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
780 return pool->next_mapping ? 0 : -ENOMEM;
783 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
785 struct dm_thin_new_mapping *m = pool->next_mapping;
787 BUG_ON(!pool->next_mapping);
789 memset(m, 0, sizeof(struct dm_thin_new_mapping));
790 INIT_LIST_HEAD(&m->list);
793 pool->next_mapping = NULL;
798 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
799 struct dm_dev *origin, dm_block_t data_origin,
800 dm_block_t data_dest,
801 struct dm_bio_prison_cell *cell, struct bio *bio)
804 struct pool *pool = tc->pool;
805 struct dm_thin_new_mapping *m = get_next_mapping(pool);
808 m->virt_block = virt_block;
809 m->data_block = data_dest;
812 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
816 * IO to pool_dev remaps to the pool target's data_dev.
818 * If the whole block of data is being overwritten, we can issue the
819 * bio immediately. Otherwise we use kcopyd to clone the data first.
821 if (io_overwrites_block(pool, bio)) {
822 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
824 h->overwrite_mapping = m;
826 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
827 inc_all_io_entry(pool, bio);
828 remap_and_issue(tc, bio, data_dest);
830 struct dm_io_region from, to;
832 from.bdev = origin->bdev;
833 from.sector = data_origin * pool->sectors_per_block;
834 from.count = pool->sectors_per_block;
836 to.bdev = tc->pool_dev->bdev;
837 to.sector = data_dest * pool->sectors_per_block;
838 to.count = pool->sectors_per_block;
840 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
841 0, copy_complete, m);
843 mempool_free(m, pool->mapping_pool);
844 DMERR_LIMIT("dm_kcopyd_copy() failed");
845 cell_error(pool, cell);
850 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
851 dm_block_t data_origin, dm_block_t data_dest,
852 struct dm_bio_prison_cell *cell, struct bio *bio)
854 schedule_copy(tc, virt_block, tc->pool_dev,
855 data_origin, data_dest, cell, bio);
858 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
859 dm_block_t data_dest,
860 struct dm_bio_prison_cell *cell, struct bio *bio)
862 schedule_copy(tc, virt_block, tc->origin_dev,
863 virt_block, data_dest, cell, bio);
866 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
867 dm_block_t data_block, struct dm_bio_prison_cell *cell,
870 struct pool *pool = tc->pool;
871 struct dm_thin_new_mapping *m = get_next_mapping(pool);
876 m->virt_block = virt_block;
877 m->data_block = data_block;
881 * If the whole block of data is being overwritten or we are not
882 * zeroing pre-existing data, we can issue the bio immediately.
883 * Otherwise we use kcopyd to zero the data first.
885 if (!pool->pf.zero_new_blocks)
886 process_prepared_mapping(m);
888 else if (io_overwrites_block(pool, bio)) {
889 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
891 h->overwrite_mapping = m;
893 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
894 inc_all_io_entry(pool, bio);
895 remap_and_issue(tc, bio, data_block);
898 struct dm_io_region to;
900 to.bdev = tc->pool_dev->bdev;
901 to.sector = data_block * pool->sectors_per_block;
902 to.count = pool->sectors_per_block;
904 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
906 mempool_free(m, pool->mapping_pool);
907 DMERR_LIMIT("dm_kcopyd_zero() failed");
908 cell_error(pool, cell);
914 * A non-zero return indicates read_only or fail_io mode.
915 * Many callers don't care about the return value.
917 static int commit(struct pool *pool)
921 if (get_pool_mode(pool) != PM_WRITE)
924 r = dm_pool_commit_metadata(pool->pmd);
926 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
931 static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
935 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
936 DMWARN("%s: reached low water mark for data device: sending event.",
937 dm_device_name(pool->pool_md));
938 spin_lock_irqsave(&pool->lock, flags);
939 pool->low_water_triggered = true;
940 spin_unlock_irqrestore(&pool->lock, flags);
941 dm_table_event(pool->ti->table);
945 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
947 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
950 dm_block_t free_blocks;
951 struct pool *pool = tc->pool;
953 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
956 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
958 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
962 check_low_water_mark(pool, free_blocks);
966 * Try to commit to see if that will free up some
973 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
975 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
980 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
985 r = dm_pool_alloc_data_block(pool->pmd, result);
987 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
995 * If we have run out of space, queue bios until the device is
996 * resumed, presumably after having been reloaded with more space.
998 static void retry_on_resume(struct bio *bio)
1000 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1001 struct thin_c *tc = h->tc;
1002 struct pool *pool = tc->pool;
1003 unsigned long flags;
1005 spin_lock_irqsave(&pool->lock, flags);
1006 bio_list_add(&pool->retry_on_resume_list, bio);
1007 spin_unlock_irqrestore(&pool->lock, flags);
1010 static bool should_error_unserviceable_bio(struct pool *pool)
1012 enum pool_mode m = get_pool_mode(pool);
1016 /* Shouldn't get here */
1017 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1020 case PM_OUT_OF_DATA_SPACE:
1021 return pool->pf.error_if_no_space;
1027 /* Shouldn't get here */
1028 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1033 static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1035 if (should_error_unserviceable_bio(pool))
1038 retry_on_resume(bio);
1041 static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1044 struct bio_list bios;
1046 if (should_error_unserviceable_bio(pool)) {
1047 cell_error(pool, cell);
1051 bio_list_init(&bios);
1052 cell_release(pool, cell, &bios);
1054 if (should_error_unserviceable_bio(pool))
1055 while ((bio = bio_list_pop(&bios)))
1058 while ((bio = bio_list_pop(&bios)))
1059 retry_on_resume(bio);
1062 static void process_discard(struct thin_c *tc, struct bio *bio)
1065 unsigned long flags;
1066 struct pool *pool = tc->pool;
1067 struct dm_bio_prison_cell *cell, *cell2;
1068 struct dm_cell_key key, key2;
1069 dm_block_t block = get_bio_block(tc, bio);
1070 struct dm_thin_lookup_result lookup_result;
1071 struct dm_thin_new_mapping *m;
1073 build_virtual_key(tc->td, block, &key);
1074 if (bio_detain(tc->pool, &key, bio, &cell))
1077 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1081 * Check nobody is fiddling with this pool block. This can
1082 * happen if someone's in the process of breaking sharing
1085 build_data_key(tc->td, lookup_result.block, &key2);
1086 if (bio_detain(tc->pool, &key2, bio, &cell2)) {
1087 cell_defer_no_holder(tc, cell);
1091 if (io_overlaps_block(pool, bio)) {
1093 * IO may still be going to the destination block. We must
1094 * quiesce before we can do the removal.
1096 m = get_next_mapping(pool);
1098 m->pass_discard = pool->pf.discard_passdown;
1099 m->definitely_not_shared = !lookup_result.shared;
1100 m->virt_block = block;
1101 m->data_block = lookup_result.block;
1106 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
1107 spin_lock_irqsave(&pool->lock, flags);
1108 list_add_tail(&m->list, &pool->prepared_discards);
1109 spin_unlock_irqrestore(&pool->lock, flags);
1113 inc_all_io_entry(pool, bio);
1114 cell_defer_no_holder(tc, cell);
1115 cell_defer_no_holder(tc, cell2);
1118 * The DM core makes sure that the discard doesn't span
1119 * a block boundary. So we submit the discard of a
1120 * partial block appropriately.
1122 if ((!lookup_result.shared) && pool->pf.discard_passdown)
1123 remap_and_issue(tc, bio, lookup_result.block);
1131 * It isn't provisioned, just forget it.
1133 cell_defer_no_holder(tc, cell);
1138 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1140 cell_defer_no_holder(tc, cell);
1146 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1147 struct dm_cell_key *key,
1148 struct dm_thin_lookup_result *lookup_result,
1149 struct dm_bio_prison_cell *cell)
1152 dm_block_t data_block;
1153 struct pool *pool = tc->pool;
1155 r = alloc_data_block(tc, &data_block);
1158 schedule_internal_copy(tc, block, lookup_result->block,
1159 data_block, cell, bio);
1163 retry_bios_on_resume(pool, cell);
1167 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1169 cell_error(pool, cell);
1174 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1176 struct dm_thin_lookup_result *lookup_result)
1178 struct dm_bio_prison_cell *cell;
1179 struct pool *pool = tc->pool;
1180 struct dm_cell_key key;
1183 * If cell is already occupied, then sharing is already in the process
1184 * of being broken so we have nothing further to do here.
1186 build_data_key(tc->td, lookup_result->block, &key);
1187 if (bio_detain(pool, &key, bio, &cell))
1190 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size)
1191 break_sharing(tc, bio, block, &key, lookup_result, cell);
1193 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1195 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1196 inc_all_io_entry(pool, bio);
1197 cell_defer_no_holder(tc, cell);
1199 remap_and_issue(tc, bio, lookup_result->block);
1203 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1204 struct dm_bio_prison_cell *cell)
1207 dm_block_t data_block;
1208 struct pool *pool = tc->pool;
1211 * Remap empty bios (flushes) immediately, without provisioning.
1213 if (!bio->bi_iter.bi_size) {
1214 inc_all_io_entry(pool, bio);
1215 cell_defer_no_holder(tc, cell);
1217 remap_and_issue(tc, bio, 0);
1222 * Fill read bios with zeroes and complete them immediately.
1224 if (bio_data_dir(bio) == READ) {
1226 cell_defer_no_holder(tc, cell);
1231 r = alloc_data_block(tc, &data_block);
1235 schedule_external_copy(tc, block, data_block, cell, bio);
1237 schedule_zero(tc, block, data_block, cell, bio);
1241 retry_bios_on_resume(pool, cell);
1245 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1247 cell_error(pool, cell);
1252 static void process_bio(struct thin_c *tc, struct bio *bio)
1255 struct pool *pool = tc->pool;
1256 dm_block_t block = get_bio_block(tc, bio);
1257 struct dm_bio_prison_cell *cell;
1258 struct dm_cell_key key;
1259 struct dm_thin_lookup_result lookup_result;
1262 * If cell is already occupied, then the block is already
1263 * being provisioned so we have nothing further to do here.
1265 build_virtual_key(tc->td, block, &key);
1266 if (bio_detain(pool, &key, bio, &cell))
1269 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1272 if (lookup_result.shared) {
1273 process_shared_bio(tc, bio, block, &lookup_result);
1274 cell_defer_no_holder(tc, cell); /* FIXME: pass this cell into process_shared? */
1276 inc_all_io_entry(pool, bio);
1277 cell_defer_no_holder(tc, cell);
1279 remap_and_issue(tc, bio, lookup_result.block);
1284 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1285 inc_all_io_entry(pool, bio);
1286 cell_defer_no_holder(tc, cell);
1288 remap_to_origin_and_issue(tc, bio);
1290 provision_block(tc, bio, block, cell);
1294 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1296 cell_defer_no_holder(tc, cell);
1302 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1305 int rw = bio_data_dir(bio);
1306 dm_block_t block = get_bio_block(tc, bio);
1307 struct dm_thin_lookup_result lookup_result;
1309 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1312 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size)
1313 handle_unserviceable_bio(tc->pool, bio);
1315 inc_all_io_entry(tc->pool, bio);
1316 remap_and_issue(tc, bio, lookup_result.block);
1322 handle_unserviceable_bio(tc->pool, bio);
1326 if (tc->origin_dev) {
1327 inc_all_io_entry(tc->pool, bio);
1328 remap_to_origin_and_issue(tc, bio);
1337 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1344 static void process_bio_success(struct thin_c *tc, struct bio *bio)
1349 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1355 * FIXME: should we also commit due to size of transaction, measured in
1358 static int need_commit_due_to_time(struct pool *pool)
1360 return jiffies < pool->last_commit_jiffies ||
1361 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1364 static void process_deferred_bios(struct pool *pool)
1366 unsigned long flags;
1368 struct bio_list bios;
1370 bio_list_init(&bios);
1372 spin_lock_irqsave(&pool->lock, flags);
1373 bio_list_merge(&bios, &pool->deferred_bios);
1374 bio_list_init(&pool->deferred_bios);
1375 spin_unlock_irqrestore(&pool->lock, flags);
1377 while ((bio = bio_list_pop(&bios))) {
1378 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1379 struct thin_c *tc = h->tc;
1382 * If we've got no free new_mapping structs, and processing
1383 * this bio might require one, we pause until there are some
1384 * prepared mappings to process.
1386 if (ensure_next_mapping(pool)) {
1387 spin_lock_irqsave(&pool->lock, flags);
1388 bio_list_merge(&pool->deferred_bios, &bios);
1389 spin_unlock_irqrestore(&pool->lock, flags);
1394 if (bio->bi_rw & REQ_DISCARD)
1395 pool->process_discard(tc, bio);
1397 pool->process_bio(tc, bio);
1401 * If there are any deferred flush bios, we must commit
1402 * the metadata before issuing them.
1404 bio_list_init(&bios);
1405 spin_lock_irqsave(&pool->lock, flags);
1406 bio_list_merge(&bios, &pool->deferred_flush_bios);
1407 bio_list_init(&pool->deferred_flush_bios);
1408 spin_unlock_irqrestore(&pool->lock, flags);
1410 if (bio_list_empty(&bios) &&
1411 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
1415 while ((bio = bio_list_pop(&bios)))
1419 pool->last_commit_jiffies = jiffies;
1421 while ((bio = bio_list_pop(&bios)))
1422 generic_make_request(bio);
1425 static void do_worker(struct work_struct *ws)
1427 struct pool *pool = container_of(ws, struct pool, worker);
1429 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1430 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1431 process_deferred_bios(pool);
1435 * We want to commit periodically so that not too much
1436 * unwritten data builds up.
1438 static void do_waker(struct work_struct *ws)
1440 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1442 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1445 /*----------------------------------------------------------------*/
1447 static enum pool_mode get_pool_mode(struct pool *pool)
1449 return pool->pf.mode;
1452 static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode)
1454 dm_table_event(pool->ti->table);
1455 DMINFO("%s: switching pool to %s mode",
1456 dm_device_name(pool->pool_md), new_mode);
1459 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
1461 struct pool_c *pt = pool->ti->private;
1462 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
1463 enum pool_mode old_mode = get_pool_mode(pool);
1466 * Never allow the pool to transition to PM_WRITE mode if user
1467 * intervention is required to verify metadata and data consistency.
1469 if (new_mode == PM_WRITE && needs_check) {
1470 DMERR("%s: unable to switch pool to write mode until repaired.",
1471 dm_device_name(pool->pool_md));
1472 if (old_mode != new_mode)
1473 new_mode = old_mode;
1475 new_mode = PM_READ_ONLY;
1478 * If we were in PM_FAIL mode, rollback of metadata failed. We're
1479 * not going to recover without a thin_repair. So we never let the
1480 * pool move out of the old mode.
1482 if (old_mode == PM_FAIL)
1483 new_mode = old_mode;
1487 if (old_mode != new_mode)
1488 notify_of_pool_mode_change(pool, "failure");
1489 dm_pool_metadata_read_only(pool->pmd);
1490 pool->process_bio = process_bio_fail;
1491 pool->process_discard = process_bio_fail;
1492 pool->process_prepared_mapping = process_prepared_mapping_fail;
1493 pool->process_prepared_discard = process_prepared_discard_fail;
1495 error_retry_list(pool);
1499 if (old_mode != new_mode)
1500 notify_of_pool_mode_change(pool, "read-only");
1501 dm_pool_metadata_read_only(pool->pmd);
1502 pool->process_bio = process_bio_read_only;
1503 pool->process_discard = process_bio_success;
1504 pool->process_prepared_mapping = process_prepared_mapping_fail;
1505 pool->process_prepared_discard = process_prepared_discard_passdown;
1507 error_retry_list(pool);
1510 case PM_OUT_OF_DATA_SPACE:
1512 * Ideally we'd never hit this state; the low water mark
1513 * would trigger userland to extend the pool before we
1514 * completely run out of data space. However, many small
1515 * IOs to unprovisioned space can consume data space at an
1516 * alarming rate. Adjust your low water mark if you're
1517 * frequently seeing this mode.
1519 if (old_mode != new_mode)
1520 notify_of_pool_mode_change(pool, "out-of-data-space");
1521 pool->process_bio = process_bio_read_only;
1522 pool->process_discard = process_discard;
1523 pool->process_prepared_mapping = process_prepared_mapping;
1524 pool->process_prepared_discard = process_prepared_discard_passdown;
1528 if (old_mode != new_mode)
1529 notify_of_pool_mode_change(pool, "write");
1530 dm_pool_metadata_read_write(pool->pmd);
1531 pool->process_bio = process_bio;
1532 pool->process_discard = process_discard;
1533 pool->process_prepared_mapping = process_prepared_mapping;
1534 pool->process_prepared_discard = process_prepared_discard;
1538 pool->pf.mode = new_mode;
1540 * The pool mode may have changed, sync it so bind_control_target()
1541 * doesn't cause an unexpected mode transition on resume.
1543 pt->adjusted_pf.mode = new_mode;
1546 static void abort_transaction(struct pool *pool)
1548 const char *dev_name = dm_device_name(pool->pool_md);
1550 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
1551 if (dm_pool_abort_metadata(pool->pmd)) {
1552 DMERR("%s: failed to abort metadata transaction", dev_name);
1553 set_pool_mode(pool, PM_FAIL);
1556 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
1557 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
1558 set_pool_mode(pool, PM_FAIL);
1562 static void metadata_operation_failed(struct pool *pool, const char *op, int r)
1564 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
1565 dm_device_name(pool->pool_md), op, r);
1567 abort_transaction(pool);
1568 set_pool_mode(pool, PM_READ_ONLY);
1571 /*----------------------------------------------------------------*/
1574 * Mapping functions.
1578 * Called only while mapping a thin bio to hand it over to the workqueue.
1580 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1582 unsigned long flags;
1583 struct pool *pool = tc->pool;
1585 spin_lock_irqsave(&pool->lock, flags);
1586 bio_list_add(&pool->deferred_bios, bio);
1587 spin_unlock_irqrestore(&pool->lock, flags);
1592 static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
1594 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1597 h->shared_read_entry = NULL;
1598 h->all_io_entry = NULL;
1599 h->overwrite_mapping = NULL;
1603 * Non-blocking function called from the thin target's map function.
1605 static int thin_bio_map(struct dm_target *ti, struct bio *bio)
1608 struct thin_c *tc = ti->private;
1609 dm_block_t block = get_bio_block(tc, bio);
1610 struct dm_thin_device *td = tc->td;
1611 struct dm_thin_lookup_result result;
1612 struct dm_bio_prison_cell cell1, cell2;
1613 struct dm_bio_prison_cell *cell_result;
1614 struct dm_cell_key key;
1616 thin_hook_bio(tc, bio);
1618 if (get_pool_mode(tc->pool) == PM_FAIL) {
1620 return DM_MAPIO_SUBMITTED;
1623 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
1624 thin_defer_bio(tc, bio);
1625 return DM_MAPIO_SUBMITTED;
1628 r = dm_thin_find_block(td, block, 0, &result);
1631 * Note that we defer readahead too.
1635 if (unlikely(result.shared)) {
1637 * We have a race condition here between the
1638 * result.shared value returned by the lookup and
1639 * snapshot creation, which may cause new
1642 * To avoid this always quiesce the origin before
1643 * taking the snap. You want to do this anyway to
1644 * ensure a consistent application view
1647 * More distant ancestors are irrelevant. The
1648 * shared flag will be set in their case.
1650 thin_defer_bio(tc, bio);
1651 return DM_MAPIO_SUBMITTED;
1654 build_virtual_key(tc->td, block, &key);
1655 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
1656 return DM_MAPIO_SUBMITTED;
1658 build_data_key(tc->td, result.block, &key);
1659 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
1660 cell_defer_no_holder_no_free(tc, &cell1);
1661 return DM_MAPIO_SUBMITTED;
1664 inc_all_io_entry(tc->pool, bio);
1665 cell_defer_no_holder_no_free(tc, &cell2);
1666 cell_defer_no_holder_no_free(tc, &cell1);
1668 remap(tc, bio, result.block);
1669 return DM_MAPIO_REMAPPED;
1672 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
1674 * This block isn't provisioned, and we have no way
1677 handle_unserviceable_bio(tc->pool, bio);
1678 return DM_MAPIO_SUBMITTED;
1684 * In future, the failed dm_thin_find_block above could
1685 * provide the hint to load the metadata into cache.
1687 thin_defer_bio(tc, bio);
1688 return DM_MAPIO_SUBMITTED;
1692 * Must always call bio_io_error on failure.
1693 * dm_thin_find_block can fail with -EINVAL if the
1694 * pool is switched to fail-io mode.
1697 return DM_MAPIO_SUBMITTED;
1701 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1704 unsigned long flags;
1705 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1707 spin_lock_irqsave(&pt->pool->lock, flags);
1708 r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1709 spin_unlock_irqrestore(&pt->pool->lock, flags);
1712 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1713 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1719 static void __requeue_bios(struct pool *pool)
1721 bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1722 bio_list_init(&pool->retry_on_resume_list);
1725 /*----------------------------------------------------------------
1726 * Binding of control targets to a pool object
1727 *--------------------------------------------------------------*/
1728 static bool data_dev_supports_discard(struct pool_c *pt)
1730 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1732 return q && blk_queue_discard(q);
1735 static bool is_factor(sector_t block_size, uint32_t n)
1737 return !sector_div(block_size, n);
1741 * If discard_passdown was enabled verify that the data device
1742 * supports discards. Disable discard_passdown if not.
1744 static void disable_passdown_if_not_supported(struct pool_c *pt)
1746 struct pool *pool = pt->pool;
1747 struct block_device *data_bdev = pt->data_dev->bdev;
1748 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
1749 sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
1750 const char *reason = NULL;
1751 char buf[BDEVNAME_SIZE];
1753 if (!pt->adjusted_pf.discard_passdown)
1756 if (!data_dev_supports_discard(pt))
1757 reason = "discard unsupported";
1759 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
1760 reason = "max discard sectors smaller than a block";
1762 else if (data_limits->discard_granularity > block_size)
1763 reason = "discard granularity larger than a block";
1765 else if (!is_factor(block_size, data_limits->discard_granularity))
1766 reason = "discard granularity not a factor of block size";
1769 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
1770 pt->adjusted_pf.discard_passdown = false;
1774 static int bind_control_target(struct pool *pool, struct dm_target *ti)
1776 struct pool_c *pt = ti->private;
1779 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
1781 enum pool_mode old_mode = get_pool_mode(pool);
1782 enum pool_mode new_mode = pt->adjusted_pf.mode;
1785 * Don't change the pool's mode until set_pool_mode() below.
1786 * Otherwise the pool's process_* function pointers may
1787 * not match the desired pool mode.
1789 pt->adjusted_pf.mode = old_mode;
1792 pool->pf = pt->adjusted_pf;
1793 pool->low_water_blocks = pt->low_water_blocks;
1795 set_pool_mode(pool, new_mode);
1800 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1806 /*----------------------------------------------------------------
1808 *--------------------------------------------------------------*/
1809 /* Initialize pool features. */
1810 static void pool_features_init(struct pool_features *pf)
1812 pf->mode = PM_WRITE;
1813 pf->zero_new_blocks = true;
1814 pf->discard_enabled = true;
1815 pf->discard_passdown = true;
1816 pf->error_if_no_space = false;
1819 static void __pool_destroy(struct pool *pool)
1821 __pool_table_remove(pool);
1823 if (dm_pool_metadata_close(pool->pmd) < 0)
1824 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1826 dm_bio_prison_destroy(pool->prison);
1827 dm_kcopyd_client_destroy(pool->copier);
1830 destroy_workqueue(pool->wq);
1832 if (pool->next_mapping)
1833 mempool_free(pool->next_mapping, pool->mapping_pool);
1834 mempool_destroy(pool->mapping_pool);
1835 dm_deferred_set_destroy(pool->shared_read_ds);
1836 dm_deferred_set_destroy(pool->all_io_ds);
1840 static struct kmem_cache *_new_mapping_cache;
1842 static struct pool *pool_create(struct mapped_device *pool_md,
1843 struct block_device *metadata_dev,
1844 unsigned long block_size,
1845 int read_only, char **error)
1850 struct dm_pool_metadata *pmd;
1851 bool format_device = read_only ? false : true;
1853 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
1855 *error = "Error creating metadata object";
1856 return (struct pool *)pmd;
1859 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1861 *error = "Error allocating memory for pool";
1862 err_p = ERR_PTR(-ENOMEM);
1867 pool->sectors_per_block = block_size;
1868 if (block_size & (block_size - 1))
1869 pool->sectors_per_block_shift = -1;
1871 pool->sectors_per_block_shift = __ffs(block_size);
1872 pool->low_water_blocks = 0;
1873 pool_features_init(&pool->pf);
1874 pool->prison = dm_bio_prison_create(PRISON_CELLS);
1875 if (!pool->prison) {
1876 *error = "Error creating pool's bio prison";
1877 err_p = ERR_PTR(-ENOMEM);
1881 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1882 if (IS_ERR(pool->copier)) {
1883 r = PTR_ERR(pool->copier);
1884 *error = "Error creating pool's kcopyd client";
1886 goto bad_kcopyd_client;
1890 * Create singlethreaded workqueue that will service all devices
1891 * that use this metadata.
1893 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1895 *error = "Error creating pool's workqueue";
1896 err_p = ERR_PTR(-ENOMEM);
1900 INIT_WORK(&pool->worker, do_worker);
1901 INIT_DELAYED_WORK(&pool->waker, do_waker);
1902 spin_lock_init(&pool->lock);
1903 bio_list_init(&pool->deferred_bios);
1904 bio_list_init(&pool->deferred_flush_bios);
1905 INIT_LIST_HEAD(&pool->prepared_mappings);
1906 INIT_LIST_HEAD(&pool->prepared_discards);
1907 pool->low_water_triggered = false;
1908 bio_list_init(&pool->retry_on_resume_list);
1910 pool->shared_read_ds = dm_deferred_set_create();
1911 if (!pool->shared_read_ds) {
1912 *error = "Error creating pool's shared read deferred set";
1913 err_p = ERR_PTR(-ENOMEM);
1914 goto bad_shared_read_ds;
1917 pool->all_io_ds = dm_deferred_set_create();
1918 if (!pool->all_io_ds) {
1919 *error = "Error creating pool's all io deferred set";
1920 err_p = ERR_PTR(-ENOMEM);
1924 pool->next_mapping = NULL;
1925 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
1926 _new_mapping_cache);
1927 if (!pool->mapping_pool) {
1928 *error = "Error creating pool's mapping mempool";
1929 err_p = ERR_PTR(-ENOMEM);
1930 goto bad_mapping_pool;
1933 pool->ref_count = 1;
1934 pool->last_commit_jiffies = jiffies;
1935 pool->pool_md = pool_md;
1936 pool->md_dev = metadata_dev;
1937 __pool_table_insert(pool);
1942 dm_deferred_set_destroy(pool->all_io_ds);
1944 dm_deferred_set_destroy(pool->shared_read_ds);
1946 destroy_workqueue(pool->wq);
1948 dm_kcopyd_client_destroy(pool->copier);
1950 dm_bio_prison_destroy(pool->prison);
1954 if (dm_pool_metadata_close(pmd))
1955 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1960 static void __pool_inc(struct pool *pool)
1962 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1966 static void __pool_dec(struct pool *pool)
1968 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1969 BUG_ON(!pool->ref_count);
1970 if (!--pool->ref_count)
1971 __pool_destroy(pool);
1974 static struct pool *__pool_find(struct mapped_device *pool_md,
1975 struct block_device *metadata_dev,
1976 unsigned long block_size, int read_only,
1977 char **error, int *created)
1979 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1982 if (pool->pool_md != pool_md) {
1983 *error = "metadata device already in use by a pool";
1984 return ERR_PTR(-EBUSY);
1989 pool = __pool_table_lookup(pool_md);
1991 if (pool->md_dev != metadata_dev) {
1992 *error = "different pool cannot replace a pool";
1993 return ERR_PTR(-EINVAL);
1998 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
2006 /*----------------------------------------------------------------
2007 * Pool target methods
2008 *--------------------------------------------------------------*/
2009 static void pool_dtr(struct dm_target *ti)
2011 struct pool_c *pt = ti->private;
2013 mutex_lock(&dm_thin_pool_table.mutex);
2015 unbind_control_target(pt->pool, ti);
2016 __pool_dec(pt->pool);
2017 dm_put_device(ti, pt->metadata_dev);
2018 dm_put_device(ti, pt->data_dev);
2021 mutex_unlock(&dm_thin_pool_table.mutex);
2024 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
2025 struct dm_target *ti)
2029 const char *arg_name;
2031 static struct dm_arg _args[] = {
2032 {0, 4, "Invalid number of pool feature arguments"},
2036 * No feature arguments supplied.
2041 r = dm_read_arg_group(_args, as, &argc, &ti->error);
2045 while (argc && !r) {
2046 arg_name = dm_shift_arg(as);
2049 if (!strcasecmp(arg_name, "skip_block_zeroing"))
2050 pf->zero_new_blocks = false;
2052 else if (!strcasecmp(arg_name, "ignore_discard"))
2053 pf->discard_enabled = false;
2055 else if (!strcasecmp(arg_name, "no_discard_passdown"))
2056 pf->discard_passdown = false;
2058 else if (!strcasecmp(arg_name, "read_only"))
2059 pf->mode = PM_READ_ONLY;
2061 else if (!strcasecmp(arg_name, "error_if_no_space"))
2062 pf->error_if_no_space = true;
2065 ti->error = "Unrecognised pool feature requested";
2074 static void metadata_low_callback(void *context)
2076 struct pool *pool = context;
2078 DMWARN("%s: reached low water mark for metadata device: sending event.",
2079 dm_device_name(pool->pool_md));
2081 dm_table_event(pool->ti->table);
2084 static sector_t get_dev_size(struct block_device *bdev)
2086 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
2089 static void warn_if_metadata_device_too_big(struct block_device *bdev)
2091 sector_t metadata_dev_size = get_dev_size(bdev);
2092 char buffer[BDEVNAME_SIZE];
2094 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
2095 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
2096 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
2099 static sector_t get_metadata_dev_size(struct block_device *bdev)
2101 sector_t metadata_dev_size = get_dev_size(bdev);
2103 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
2104 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
2106 return metadata_dev_size;
2109 static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
2111 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
2113 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
2115 return metadata_dev_size;
2119 * When a metadata threshold is crossed a dm event is triggered, and
2120 * userland should respond by growing the metadata device. We could let
2121 * userland set the threshold, like we do with the data threshold, but I'm
2122 * not sure they know enough to do this well.
2124 static dm_block_t calc_metadata_threshold(struct pool_c *pt)
2127 * 4M is ample for all ops with the possible exception of thin
2128 * device deletion which is harmless if it fails (just retry the
2129 * delete after you've grown the device).
2131 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
2132 return min((dm_block_t)1024ULL /* 4M */, quarter);
2136 * thin-pool <metadata dev> <data dev>
2137 * <data block size (sectors)>
2138 * <low water mark (blocks)>
2139 * [<#feature args> [<arg>]*]
2141 * Optional feature arguments are:
2142 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
2143 * ignore_discard: disable discard
2144 * no_discard_passdown: don't pass discards down to the data device
2145 * read_only: Don't allow any changes to be made to the pool metadata.
2146 * error_if_no_space: error IOs, instead of queueing, if no space.
2148 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
2150 int r, pool_created = 0;
2153 struct pool_features pf;
2154 struct dm_arg_set as;
2155 struct dm_dev *data_dev;
2156 unsigned long block_size;
2157 dm_block_t low_water_blocks;
2158 struct dm_dev *metadata_dev;
2159 fmode_t metadata_mode;
2162 * FIXME Remove validation from scope of lock.
2164 mutex_lock(&dm_thin_pool_table.mutex);
2167 ti->error = "Invalid argument count";
2176 * Set default pool features.
2178 pool_features_init(&pf);
2180 dm_consume_args(&as, 4);
2181 r = parse_pool_features(&as, &pf, ti);
2185 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
2186 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
2188 ti->error = "Error opening metadata block device";
2191 warn_if_metadata_device_too_big(metadata_dev->bdev);
2193 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
2195 ti->error = "Error getting data device";
2199 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
2200 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
2201 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
2202 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
2203 ti->error = "Invalid block size";
2208 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
2209 ti->error = "Invalid low water mark";
2214 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
2220 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
2221 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
2228 * 'pool_created' reflects whether this is the first table load.
2229 * Top level discard support is not allowed to be changed after
2230 * initial load. This would require a pool reload to trigger thin
2233 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
2234 ti->error = "Discard support cannot be disabled once enabled";
2236 goto out_flags_changed;
2241 pt->metadata_dev = metadata_dev;
2242 pt->data_dev = data_dev;
2243 pt->low_water_blocks = low_water_blocks;
2244 pt->adjusted_pf = pt->requested_pf = pf;
2245 ti->num_flush_bios = 1;
2248 * Only need to enable discards if the pool should pass
2249 * them down to the data device. The thin device's discard
2250 * processing will cause mappings to be removed from the btree.
2252 ti->discard_zeroes_data_unsupported = true;
2253 if (pf.discard_enabled && pf.discard_passdown) {
2254 ti->num_discard_bios = 1;
2257 * Setting 'discards_supported' circumvents the normal
2258 * stacking of discard limits (this keeps the pool and
2259 * thin devices' discard limits consistent).
2261 ti->discards_supported = true;
2265 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
2266 calc_metadata_threshold(pt),
2267 metadata_low_callback,
2272 pt->callbacks.congested_fn = pool_is_congested;
2273 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2275 mutex_unlock(&dm_thin_pool_table.mutex);
2284 dm_put_device(ti, data_dev);
2286 dm_put_device(ti, metadata_dev);
2288 mutex_unlock(&dm_thin_pool_table.mutex);
2293 static int pool_map(struct dm_target *ti, struct bio *bio)
2296 struct pool_c *pt = ti->private;
2297 struct pool *pool = pt->pool;
2298 unsigned long flags;
2301 * As this is a singleton target, ti->begin is always zero.
2303 spin_lock_irqsave(&pool->lock, flags);
2304 bio->bi_bdev = pt->data_dev->bdev;
2305 r = DM_MAPIO_REMAPPED;
2306 spin_unlock_irqrestore(&pool->lock, flags);
2311 static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
2314 struct pool_c *pt = ti->private;
2315 struct pool *pool = pt->pool;
2316 sector_t data_size = ti->len;
2317 dm_block_t sb_data_size;
2319 *need_commit = false;
2321 (void) sector_div(data_size, pool->sectors_per_block);
2323 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2325 DMERR("%s: failed to retrieve data device size",
2326 dm_device_name(pool->pool_md));
2330 if (data_size < sb_data_size) {
2331 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
2332 dm_device_name(pool->pool_md),
2333 (unsigned long long)data_size, sb_data_size);
2336 } else if (data_size > sb_data_size) {
2337 if (dm_pool_metadata_needs_check(pool->pmd)) {
2338 DMERR("%s: unable to grow the data device until repaired.",
2339 dm_device_name(pool->pool_md));
2344 DMINFO("%s: growing the data device from %llu to %llu blocks",
2345 dm_device_name(pool->pool_md),
2346 sb_data_size, (unsigned long long)data_size);
2347 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2349 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
2353 *need_commit = true;
2359 static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
2362 struct pool_c *pt = ti->private;
2363 struct pool *pool = pt->pool;
2364 dm_block_t metadata_dev_size, sb_metadata_dev_size;
2366 *need_commit = false;
2368 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
2370 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
2372 DMERR("%s: failed to retrieve metadata device size",
2373 dm_device_name(pool->pool_md));
2377 if (metadata_dev_size < sb_metadata_dev_size) {
2378 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
2379 dm_device_name(pool->pool_md),
2380 metadata_dev_size, sb_metadata_dev_size);
2383 } else if (metadata_dev_size > sb_metadata_dev_size) {
2384 if (dm_pool_metadata_needs_check(pool->pmd)) {
2385 DMERR("%s: unable to grow the metadata device until repaired.",
2386 dm_device_name(pool->pool_md));
2390 warn_if_metadata_device_too_big(pool->md_dev);
2391 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
2392 dm_device_name(pool->pool_md),
2393 sb_metadata_dev_size, metadata_dev_size);
2394 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
2396 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
2400 *need_commit = true;
2407 * Retrieves the number of blocks of the data device from
2408 * the superblock and compares it to the actual device size,
2409 * thus resizing the data device in case it has grown.
2411 * This both copes with opening preallocated data devices in the ctr
2412 * being followed by a resume
2414 * calling the resume method individually after userspace has
2415 * grown the data device in reaction to a table event.
2417 static int pool_preresume(struct dm_target *ti)
2420 bool need_commit1, need_commit2;
2421 struct pool_c *pt = ti->private;
2422 struct pool *pool = pt->pool;
2425 * Take control of the pool object.
2427 r = bind_control_target(pool, ti);
2431 r = maybe_resize_data_dev(ti, &need_commit1);
2435 r = maybe_resize_metadata_dev(ti, &need_commit2);
2439 if (need_commit1 || need_commit2)
2440 (void) commit(pool);
2445 static void pool_resume(struct dm_target *ti)
2447 struct pool_c *pt = ti->private;
2448 struct pool *pool = pt->pool;
2449 unsigned long flags;
2451 spin_lock_irqsave(&pool->lock, flags);
2452 pool->low_water_triggered = false;
2453 __requeue_bios(pool);
2454 spin_unlock_irqrestore(&pool->lock, flags);
2456 do_waker(&pool->waker.work);
2459 static void pool_postsuspend(struct dm_target *ti)
2461 struct pool_c *pt = ti->private;
2462 struct pool *pool = pt->pool;
2464 cancel_delayed_work(&pool->waker);
2465 flush_workqueue(pool->wq);
2466 (void) commit(pool);
2469 static int check_arg_count(unsigned argc, unsigned args_required)
2471 if (argc != args_required) {
2472 DMWARN("Message received with %u arguments instead of %u.",
2473 argc, args_required);
2480 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2482 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2483 *dev_id <= MAX_DEV_ID)
2487 DMWARN("Message received with invalid device id: %s", arg);
2492 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2497 r = check_arg_count(argc, 2);
2501 r = read_dev_id(argv[1], &dev_id, 1);
2505 r = dm_pool_create_thin(pool->pmd, dev_id);
2507 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2515 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2518 dm_thin_id origin_dev_id;
2521 r = check_arg_count(argc, 3);
2525 r = read_dev_id(argv[1], &dev_id, 1);
2529 r = read_dev_id(argv[2], &origin_dev_id, 1);
2533 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2535 DMWARN("Creation of new snapshot %s of device %s failed.",
2543 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2548 r = check_arg_count(argc, 2);
2552 r = read_dev_id(argv[1], &dev_id, 1);
2556 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2558 DMWARN("Deletion of thin device %s failed.", argv[1]);
2563 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2565 dm_thin_id old_id, new_id;
2568 r = check_arg_count(argc, 3);
2572 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2573 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2577 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2578 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2582 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2584 DMWARN("Failed to change transaction id from %s to %s.",
2592 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2596 r = check_arg_count(argc, 1);
2600 (void) commit(pool);
2602 r = dm_pool_reserve_metadata_snap(pool->pmd);
2604 DMWARN("reserve_metadata_snap message failed.");
2609 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2613 r = check_arg_count(argc, 1);
2617 r = dm_pool_release_metadata_snap(pool->pmd);
2619 DMWARN("release_metadata_snap message failed.");
2625 * Messages supported:
2626 * create_thin <dev_id>
2627 * create_snap <dev_id> <origin_id>
2629 * trim <dev_id> <new_size_in_sectors>
2630 * set_transaction_id <current_trans_id> <new_trans_id>
2631 * reserve_metadata_snap
2632 * release_metadata_snap
2634 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2637 struct pool_c *pt = ti->private;
2638 struct pool *pool = pt->pool;
2640 if (!strcasecmp(argv[0], "create_thin"))
2641 r = process_create_thin_mesg(argc, argv, pool);
2643 else if (!strcasecmp(argv[0], "create_snap"))
2644 r = process_create_snap_mesg(argc, argv, pool);
2646 else if (!strcasecmp(argv[0], "delete"))
2647 r = process_delete_mesg(argc, argv, pool);
2649 else if (!strcasecmp(argv[0], "set_transaction_id"))
2650 r = process_set_transaction_id_mesg(argc, argv, pool);
2652 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
2653 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
2655 else if (!strcasecmp(argv[0], "release_metadata_snap"))
2656 r = process_release_metadata_snap_mesg(argc, argv, pool);
2659 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2662 (void) commit(pool);
2667 static void emit_flags(struct pool_features *pf, char *result,
2668 unsigned sz, unsigned maxlen)
2670 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
2671 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
2672 pf->error_if_no_space;
2673 DMEMIT("%u ", count);
2675 if (!pf->zero_new_blocks)
2676 DMEMIT("skip_block_zeroing ");
2678 if (!pf->discard_enabled)
2679 DMEMIT("ignore_discard ");
2681 if (!pf->discard_passdown)
2682 DMEMIT("no_discard_passdown ");
2684 if (pf->mode == PM_READ_ONLY)
2685 DMEMIT("read_only ");
2687 if (pf->error_if_no_space)
2688 DMEMIT("error_if_no_space ");
2693 * <transaction id> <used metadata sectors>/<total metadata sectors>
2694 * <used data sectors>/<total data sectors> <held metadata root>
2696 static void pool_status(struct dm_target *ti, status_type_t type,
2697 unsigned status_flags, char *result, unsigned maxlen)
2701 uint64_t transaction_id;
2702 dm_block_t nr_free_blocks_data;
2703 dm_block_t nr_free_blocks_metadata;
2704 dm_block_t nr_blocks_data;
2705 dm_block_t nr_blocks_metadata;
2706 dm_block_t held_root;
2707 char buf[BDEVNAME_SIZE];
2708 char buf2[BDEVNAME_SIZE];
2709 struct pool_c *pt = ti->private;
2710 struct pool *pool = pt->pool;
2713 case STATUSTYPE_INFO:
2714 if (get_pool_mode(pool) == PM_FAIL) {
2719 /* Commit to ensure statistics aren't out-of-date */
2720 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
2721 (void) commit(pool);
2723 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
2725 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
2726 dm_device_name(pool->pool_md), r);
2730 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
2732 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
2733 dm_device_name(pool->pool_md), r);
2737 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2739 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
2740 dm_device_name(pool->pool_md), r);
2744 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
2746 DMERR("%s: dm_pool_get_free_block_count returned %d",
2747 dm_device_name(pool->pool_md), r);
2751 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2753 DMERR("%s: dm_pool_get_data_dev_size returned %d",
2754 dm_device_name(pool->pool_md), r);
2758 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
2760 DMERR("%s: dm_pool_get_metadata_snap returned %d",
2761 dm_device_name(pool->pool_md), r);
2765 DMEMIT("%llu %llu/%llu %llu/%llu ",
2766 (unsigned long long)transaction_id,
2767 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2768 (unsigned long long)nr_blocks_metadata,
2769 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2770 (unsigned long long)nr_blocks_data);
2773 DMEMIT("%llu ", held_root);
2777 if (pool->pf.mode == PM_OUT_OF_DATA_SPACE)
2778 DMEMIT("out_of_data_space ");
2779 else if (pool->pf.mode == PM_READ_ONLY)
2784 if (!pool->pf.discard_enabled)
2785 DMEMIT("ignore_discard ");
2786 else if (pool->pf.discard_passdown)
2787 DMEMIT("discard_passdown ");
2789 DMEMIT("no_discard_passdown ");
2791 if (pool->pf.error_if_no_space)
2792 DMEMIT("error_if_no_space ");
2794 DMEMIT("queue_if_no_space ");
2798 case STATUSTYPE_TABLE:
2799 DMEMIT("%s %s %lu %llu ",
2800 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2801 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2802 (unsigned long)pool->sectors_per_block,
2803 (unsigned long long)pt->low_water_blocks);
2804 emit_flags(&pt->requested_pf, result, sz, maxlen);
2813 static int pool_iterate_devices(struct dm_target *ti,
2814 iterate_devices_callout_fn fn, void *data)
2816 struct pool_c *pt = ti->private;
2818 return fn(ti, pt->data_dev, 0, ti->len, data);
2821 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2822 struct bio_vec *biovec, int max_size)
2824 struct pool_c *pt = ti->private;
2825 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2827 if (!q->merge_bvec_fn)
2830 bvm->bi_bdev = pt->data_dev->bdev;
2832 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2835 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
2837 struct pool *pool = pt->pool;
2838 struct queue_limits *data_limits;
2840 limits->max_discard_sectors = pool->sectors_per_block;
2843 * discard_granularity is just a hint, and not enforced.
2845 if (pt->adjusted_pf.discard_passdown) {
2846 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
2847 limits->discard_granularity = data_limits->discard_granularity;
2849 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
2852 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2854 struct pool_c *pt = ti->private;
2855 struct pool *pool = pt->pool;
2856 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
2859 * If the system-determined stacked limits are compatible with the
2860 * pool's blocksize (io_opt is a factor) do not override them.
2862 if (io_opt_sectors < pool->sectors_per_block ||
2863 do_div(io_opt_sectors, pool->sectors_per_block)) {
2864 blk_limits_io_min(limits, 0);
2865 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2869 * pt->adjusted_pf is a staging area for the actual features to use.
2870 * They get transferred to the live pool in bind_control_target()
2871 * called from pool_preresume().
2873 if (!pt->adjusted_pf.discard_enabled) {
2875 * Must explicitly disallow stacking discard limits otherwise the
2876 * block layer will stack them if pool's data device has support.
2877 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
2878 * user to see that, so make sure to set all discard limits to 0.
2880 limits->discard_granularity = 0;
2884 disable_passdown_if_not_supported(pt);
2886 set_discard_limits(pt, limits);
2889 static struct target_type pool_target = {
2890 .name = "thin-pool",
2891 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2892 DM_TARGET_IMMUTABLE,
2893 .version = {1, 11, 0},
2894 .module = THIS_MODULE,
2898 .postsuspend = pool_postsuspend,
2899 .preresume = pool_preresume,
2900 .resume = pool_resume,
2901 .message = pool_message,
2902 .status = pool_status,
2903 .merge = pool_merge,
2904 .iterate_devices = pool_iterate_devices,
2905 .io_hints = pool_io_hints,
2908 /*----------------------------------------------------------------
2909 * Thin target methods
2910 *--------------------------------------------------------------*/
2911 static void thin_dtr(struct dm_target *ti)
2913 struct thin_c *tc = ti->private;
2915 mutex_lock(&dm_thin_pool_table.mutex);
2917 __pool_dec(tc->pool);
2918 dm_pool_close_thin_device(tc->td);
2919 dm_put_device(ti, tc->pool_dev);
2921 dm_put_device(ti, tc->origin_dev);
2924 mutex_unlock(&dm_thin_pool_table.mutex);
2928 * Thin target parameters:
2930 * <pool_dev> <dev_id> [origin_dev]
2932 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2933 * dev_id: the internal device identifier
2934 * origin_dev: a device external to the pool that should act as the origin
2936 * If the pool device has discards disabled, they get disabled for the thin
2939 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2943 struct dm_dev *pool_dev, *origin_dev;
2944 struct mapped_device *pool_md;
2946 mutex_lock(&dm_thin_pool_table.mutex);
2948 if (argc != 2 && argc != 3) {
2949 ti->error = "Invalid argument count";
2954 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2956 ti->error = "Out of memory";
2962 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
2964 ti->error = "Error opening origin device";
2965 goto bad_origin_dev;
2967 tc->origin_dev = origin_dev;
2970 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2972 ti->error = "Error opening pool device";
2975 tc->pool_dev = pool_dev;
2977 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2978 ti->error = "Invalid device id";
2983 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2985 ti->error = "Couldn't get pool mapped device";
2990 tc->pool = __pool_table_lookup(pool_md);
2992 ti->error = "Couldn't find pool object";
2994 goto bad_pool_lookup;
2996 __pool_inc(tc->pool);
2998 if (get_pool_mode(tc->pool) == PM_FAIL) {
2999 ti->error = "Couldn't open thin device, Pool is in fail mode";
3004 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
3006 ti->error = "Couldn't open thin internal device";
3010 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
3012 goto bad_target_max_io_len;
3014 ti->num_flush_bios = 1;
3015 ti->flush_supported = true;
3016 ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
3018 /* In case the pool supports discards, pass them on. */
3019 ti->discard_zeroes_data_unsupported = true;
3020 if (tc->pool->pf.discard_enabled) {
3021 ti->discards_supported = true;
3022 ti->num_discard_bios = 1;
3023 /* Discard bios must be split on a block boundary */
3024 ti->split_discard_bios = true;
3029 mutex_unlock(&dm_thin_pool_table.mutex);
3033 bad_target_max_io_len:
3034 dm_pool_close_thin_device(tc->td);
3036 __pool_dec(tc->pool);
3040 dm_put_device(ti, tc->pool_dev);
3043 dm_put_device(ti, tc->origin_dev);
3047 mutex_unlock(&dm_thin_pool_table.mutex);
3052 static int thin_map(struct dm_target *ti, struct bio *bio)
3054 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
3056 return thin_bio_map(ti, bio);
3059 static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
3061 unsigned long flags;
3062 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
3063 struct list_head work;
3064 struct dm_thin_new_mapping *m, *tmp;
3065 struct pool *pool = h->tc->pool;
3067 if (h->shared_read_entry) {
3068 INIT_LIST_HEAD(&work);
3069 dm_deferred_entry_dec(h->shared_read_entry, &work);
3071 spin_lock_irqsave(&pool->lock, flags);
3072 list_for_each_entry_safe(m, tmp, &work, list) {
3075 __maybe_add_mapping(m);
3077 spin_unlock_irqrestore(&pool->lock, flags);
3080 if (h->all_io_entry) {
3081 INIT_LIST_HEAD(&work);
3082 dm_deferred_entry_dec(h->all_io_entry, &work);
3083 if (!list_empty(&work)) {
3084 spin_lock_irqsave(&pool->lock, flags);
3085 list_for_each_entry_safe(m, tmp, &work, list)
3086 list_add_tail(&m->list, &pool->prepared_discards);
3087 spin_unlock_irqrestore(&pool->lock, flags);
3095 static void thin_postsuspend(struct dm_target *ti)
3097 if (dm_noflush_suspending(ti))
3098 requeue_io((struct thin_c *)ti->private);
3102 * <nr mapped sectors> <highest mapped sector>
3104 static void thin_status(struct dm_target *ti, status_type_t type,
3105 unsigned status_flags, char *result, unsigned maxlen)
3109 dm_block_t mapped, highest;
3110 char buf[BDEVNAME_SIZE];
3111 struct thin_c *tc = ti->private;
3113 if (get_pool_mode(tc->pool) == PM_FAIL) {
3122 case STATUSTYPE_INFO:
3123 r = dm_thin_get_mapped_count(tc->td, &mapped);
3125 DMERR("dm_thin_get_mapped_count returned %d", r);
3129 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
3131 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
3135 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
3137 DMEMIT("%llu", ((highest + 1) *
3138 tc->pool->sectors_per_block) - 1);
3143 case STATUSTYPE_TABLE:
3145 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
3146 (unsigned long) tc->dev_id);
3148 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
3159 static int thin_iterate_devices(struct dm_target *ti,
3160 iterate_devices_callout_fn fn, void *data)
3163 struct thin_c *tc = ti->private;
3164 struct pool *pool = tc->pool;
3167 * We can't call dm_pool_get_data_dev_size() since that blocks. So
3168 * we follow a more convoluted path through to the pool's target.
3171 return 0; /* nothing is bound */
3173 blocks = pool->ti->len;
3174 (void) sector_div(blocks, pool->sectors_per_block);
3176 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
3181 static struct target_type thin_target = {
3183 .version = {1, 11, 0},
3184 .module = THIS_MODULE,
3188 .end_io = thin_endio,
3189 .postsuspend = thin_postsuspend,
3190 .status = thin_status,
3191 .iterate_devices = thin_iterate_devices,
3194 /*----------------------------------------------------------------*/
3196 static int __init dm_thin_init(void)
3202 r = dm_register_target(&thin_target);
3206 r = dm_register_target(&pool_target);
3208 goto bad_pool_target;
3212 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
3213 if (!_new_mapping_cache)
3214 goto bad_new_mapping_cache;
3218 bad_new_mapping_cache:
3219 dm_unregister_target(&pool_target);
3221 dm_unregister_target(&thin_target);
3226 static void dm_thin_exit(void)
3228 dm_unregister_target(&thin_target);
3229 dm_unregister_target(&pool_target);
3231 kmem_cache_destroy(_new_mapping_cache);
3234 module_init(dm_thin_init);
3235 module_exit(dm_thin_exit);
3237 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
3238 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3239 MODULE_LICENSE("GPL");