2 * Copyright (C) 2011-2012 Red Hat UK.
4 * This file is released under the GPL.
7 #include "dm-thin-metadata.h"
8 #include "dm-bio-prison.h"
11 #include <linux/device-mapper.h>
12 #include <linux/dm-io.h>
13 #include <linux/dm-kcopyd.h>
14 #include <linux/list.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
19 #define DM_MSG_PREFIX "thin"
24 #define ENDIO_HOOK_POOL_SIZE 1024
25 #define MAPPING_POOL_SIZE 1024
26 #define PRISON_CELLS 1024
27 #define COMMIT_PERIOD HZ
29 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
30 "A percentage of time allocated for copy on write");
33 * The block size of the device holding pool data must be
34 * between 64KB and 1GB.
36 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
37 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
40 * Device id is restricted to 24 bits.
42 #define MAX_DEV_ID ((1 << 24) - 1)
45 * How do we handle breaking sharing of data blocks?
46 * =================================================
48 * We use a standard copy-on-write btree to store the mappings for the
49 * devices (note I'm talking about copy-on-write of the metadata here, not
50 * the data). When you take an internal snapshot you clone the root node
51 * of the origin btree. After this there is no concept of an origin or a
52 * snapshot. They are just two device trees that happen to point to the
55 * When we get a write in we decide if it's to a shared data block using
56 * some timestamp magic. If it is, we have to break sharing.
58 * Let's say we write to a shared block in what was the origin. The
61 * i) plug io further to this physical block. (see bio_prison code).
63 * ii) quiesce any read io to that shared data block. Obviously
64 * including all devices that share this block. (see dm_deferred_set code)
66 * iii) copy the data block to a newly allocate block. This step can be
67 * missed out if the io covers the block. (schedule_copy).
69 * iv) insert the new mapping into the origin's btree
70 * (process_prepared_mapping). This act of inserting breaks some
71 * sharing of btree nodes between the two devices. Breaking sharing only
72 * effects the btree of that specific device. Btrees for the other
73 * devices that share the block never change. The btree for the origin
74 * device as it was after the last commit is untouched, ie. we're using
75 * persistent data structures in the functional programming sense.
77 * v) unplug io to this physical block, including the io that triggered
78 * the breaking of sharing.
80 * Steps (ii) and (iii) occur in parallel.
82 * The metadata _doesn't_ need to be committed before the io continues. We
83 * get away with this because the io is always written to a _new_ block.
84 * If there's a crash, then:
86 * - The origin mapping will point to the old origin block (the shared
87 * one). This will contain the data as it was before the io that triggered
88 * the breaking of sharing came in.
90 * - The snap mapping still points to the old block. As it would after
93 * The downside of this scheme is the timestamp magic isn't perfect, and
94 * will continue to think that data block in the snapshot device is shared
95 * even after the write to the origin has broken sharing. I suspect data
96 * blocks will typically be shared by many different devices, so we're
97 * breaking sharing n + 1 times, rather than n, where n is the number of
98 * devices that reference this data block. At the moment I think the
99 * benefits far, far outweigh the disadvantages.
102 /*----------------------------------------------------------------*/
107 static void build_data_key(struct dm_thin_device *td,
108 dm_block_t b, struct dm_cell_key *key)
111 key->dev = dm_thin_dev_id(td);
115 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
116 struct dm_cell_key *key)
119 key->dev = dm_thin_dev_id(td);
123 /*----------------------------------------------------------------*/
126 * A pool device ties together a metadata device and a data device. It
127 * also provides the interface for creating and destroying internal
130 struct dm_thin_new_mapping;
133 * The pool runs in 3 modes. Ordered in degraded order for comparisons.
136 PM_WRITE, /* metadata may be changed */
137 PM_READ_ONLY, /* metadata may not be changed */
138 PM_FAIL, /* all I/O fails */
141 struct pool_features {
144 bool zero_new_blocks:1;
145 bool discard_enabled:1;
146 bool discard_passdown:1;
150 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
151 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
154 struct list_head list;
155 struct dm_target *ti; /* Only set if a pool target is bound */
157 struct mapped_device *pool_md;
158 struct block_device *md_dev;
159 struct dm_pool_metadata *pmd;
161 dm_block_t low_water_blocks;
162 uint32_t sectors_per_block;
163 int sectors_per_block_shift;
165 struct pool_features pf;
166 bool low_water_triggered:1; /* A dm event has been sent */
167 bool no_free_space:1; /* A -ENOSPC warning has been issued */
169 struct dm_bio_prison *prison;
170 struct dm_kcopyd_client *copier;
172 struct workqueue_struct *wq;
173 struct work_struct worker;
174 struct delayed_work waker;
176 unsigned long last_commit_jiffies;
180 struct bio_list deferred_bios;
181 struct bio_list deferred_flush_bios;
182 struct list_head prepared_mappings;
183 struct list_head prepared_discards;
185 struct bio_list retry_on_resume_list;
187 struct dm_deferred_set *shared_read_ds;
188 struct dm_deferred_set *all_io_ds;
190 struct dm_thin_new_mapping *next_mapping;
191 mempool_t *mapping_pool;
193 process_bio_fn process_bio;
194 process_bio_fn process_discard;
196 process_mapping_fn process_prepared_mapping;
197 process_mapping_fn process_prepared_discard;
200 static enum pool_mode get_pool_mode(struct pool *pool);
201 static void out_of_data_space(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);
403 * This section of code contains the logic for processing a thin device's IO.
404 * Much of the code depends on pool object resources (lists, workqueues, etc)
405 * but most is exclusively called from the thin target rather than the thin-pool
409 static bool block_size_is_power_of_two(struct pool *pool)
411 return pool->sectors_per_block_shift >= 0;
414 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
416 struct pool *pool = tc->pool;
417 sector_t block_nr = bio->bi_sector;
419 if (block_size_is_power_of_two(pool))
420 block_nr >>= pool->sectors_per_block_shift;
422 (void) sector_div(block_nr, pool->sectors_per_block);
427 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
429 struct pool *pool = tc->pool;
430 sector_t bi_sector = bio->bi_sector;
432 bio->bi_bdev = tc->pool_dev->bdev;
433 if (block_size_is_power_of_two(pool))
434 bio->bi_sector = (block << pool->sectors_per_block_shift) |
435 (bi_sector & (pool->sectors_per_block - 1));
437 bio->bi_sector = (block * pool->sectors_per_block) +
438 sector_div(bi_sector, pool->sectors_per_block);
441 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
443 bio->bi_bdev = tc->origin_dev->bdev;
446 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
448 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
449 dm_thin_changed_this_transaction(tc->td);
452 static void inc_all_io_entry(struct pool *pool, struct bio *bio)
454 struct dm_thin_endio_hook *h;
456 if (bio->bi_rw & REQ_DISCARD)
459 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
460 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
463 static void issue(struct thin_c *tc, struct bio *bio)
465 struct pool *pool = tc->pool;
468 if (!bio_triggers_commit(tc, bio)) {
469 generic_make_request(bio);
474 * Complete bio with an error if earlier I/O caused changes to
475 * the metadata that can't be committed e.g, due to I/O errors
476 * on the metadata device.
478 if (dm_thin_aborted_changes(tc->td)) {
484 * Batch together any bios that trigger commits and then issue a
485 * single commit for them in process_deferred_bios().
487 spin_lock_irqsave(&pool->lock, flags);
488 bio_list_add(&pool->deferred_flush_bios, bio);
489 spin_unlock_irqrestore(&pool->lock, flags);
492 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
494 remap_to_origin(tc, bio);
498 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
501 remap(tc, bio, block);
505 /*----------------------------------------------------------------*/
508 * Bio endio functions.
510 struct dm_thin_new_mapping {
511 struct list_head list;
516 bool definitely_not_shared:1;
520 dm_block_t virt_block;
521 dm_block_t data_block;
522 struct dm_bio_prison_cell *cell, *cell2;
525 * If the bio covers the whole area of a block then we can avoid
526 * zeroing or copying. Instead this bio is hooked. The bio will
527 * still be in the cell, so care has to be taken to avoid issuing
531 bio_end_io_t *saved_bi_end_io;
534 static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
536 struct pool *pool = m->tc->pool;
538 if (m->quiesced && m->prepared) {
539 list_add_tail(&m->list, &pool->prepared_mappings);
544 static void copy_complete(int read_err, unsigned long write_err, void *context)
547 struct dm_thin_new_mapping *m = context;
548 struct pool *pool = m->tc->pool;
550 m->err = read_err || write_err ? -EIO : 0;
552 spin_lock_irqsave(&pool->lock, flags);
554 __maybe_add_mapping(m);
555 spin_unlock_irqrestore(&pool->lock, flags);
558 static void overwrite_endio(struct bio *bio, int err)
561 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
562 struct dm_thin_new_mapping *m = h->overwrite_mapping;
563 struct pool *pool = m->tc->pool;
567 spin_lock_irqsave(&pool->lock, flags);
569 __maybe_add_mapping(m);
570 spin_unlock_irqrestore(&pool->lock, flags);
573 /*----------------------------------------------------------------*/
580 * Prepared mapping jobs.
584 * This sends the bios in the cell back to the deferred_bios list.
586 static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
588 struct pool *pool = tc->pool;
591 spin_lock_irqsave(&pool->lock, flags);
592 cell_release(pool, cell, &pool->deferred_bios);
593 spin_unlock_irqrestore(&tc->pool->lock, flags);
599 * Same as cell_defer above, except it omits the original holder of the cell.
601 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
603 struct pool *pool = tc->pool;
606 spin_lock_irqsave(&pool->lock, flags);
607 cell_release_no_holder(pool, cell, &pool->deferred_bios);
608 spin_unlock_irqrestore(&pool->lock, flags);
613 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
616 m->bio->bi_end_io = m->saved_bi_end_io;
617 cell_error(m->tc->pool, m->cell);
619 mempool_free(m, m->tc->pool->mapping_pool);
622 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
624 struct thin_c *tc = m->tc;
625 struct pool *pool = tc->pool;
631 bio->bi_end_io = m->saved_bi_end_io;
634 cell_error(pool, m->cell);
639 * Commit the prepared block into the mapping btree.
640 * Any I/O for this block arriving after this point will get
641 * remapped to it directly.
643 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
645 metadata_operation_failed(pool, "dm_thin_insert_block", r);
646 cell_error(pool, m->cell);
651 * Release any bios held while the block was being provisioned.
652 * If we are processing a write bio that completely covers the block,
653 * we already processed it so can ignore it now when processing
654 * the bios in the cell.
657 cell_defer_no_holder(tc, m->cell);
660 cell_defer(tc, m->cell);
664 mempool_free(m, pool->mapping_pool);
667 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
669 struct thin_c *tc = m->tc;
671 bio_io_error(m->bio);
672 cell_defer_no_holder(tc, m->cell);
673 cell_defer_no_holder(tc, m->cell2);
674 mempool_free(m, tc->pool->mapping_pool);
677 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
679 struct thin_c *tc = m->tc;
681 inc_all_io_entry(tc->pool, m->bio);
682 cell_defer_no_holder(tc, m->cell);
683 cell_defer_no_holder(tc, m->cell2);
686 if (m->definitely_not_shared)
687 remap_and_issue(tc, m->bio, m->data_block);
690 if (dm_pool_block_is_used(tc->pool->pmd, m->data_block, &used) || used)
691 bio_endio(m->bio, 0);
693 remap_and_issue(tc, m->bio, m->data_block);
696 bio_endio(m->bio, 0);
698 mempool_free(m, tc->pool->mapping_pool);
701 static void process_prepared_discard(struct dm_thin_new_mapping *m)
704 struct thin_c *tc = m->tc;
706 r = dm_thin_remove_block(tc->td, m->virt_block);
708 DMERR_LIMIT("dm_thin_remove_block() failed");
710 process_prepared_discard_passdown(m);
713 static void process_prepared(struct pool *pool, struct list_head *head,
714 process_mapping_fn *fn)
717 struct list_head maps;
718 struct dm_thin_new_mapping *m, *tmp;
720 INIT_LIST_HEAD(&maps);
721 spin_lock_irqsave(&pool->lock, flags);
722 list_splice_init(head, &maps);
723 spin_unlock_irqrestore(&pool->lock, flags);
725 list_for_each_entry_safe(m, tmp, &maps, list)
732 static int io_overlaps_block(struct pool *pool, struct bio *bio)
734 return bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT);
737 static int io_overwrites_block(struct pool *pool, struct bio *bio)
739 return (bio_data_dir(bio) == WRITE) &&
740 io_overlaps_block(pool, bio);
743 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
746 *save = bio->bi_end_io;
750 static int ensure_next_mapping(struct pool *pool)
752 if (pool->next_mapping)
755 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
757 return pool->next_mapping ? 0 : -ENOMEM;
760 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
762 struct dm_thin_new_mapping *m = pool->next_mapping;
764 BUG_ON(!pool->next_mapping);
766 memset(m, 0, sizeof(struct dm_thin_new_mapping));
767 INIT_LIST_HEAD(&m->list);
770 pool->next_mapping = NULL;
775 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
776 struct dm_dev *origin, dm_block_t data_origin,
777 dm_block_t data_dest,
778 struct dm_bio_prison_cell *cell, struct bio *bio)
781 struct pool *pool = tc->pool;
782 struct dm_thin_new_mapping *m = get_next_mapping(pool);
785 m->virt_block = virt_block;
786 m->data_block = data_dest;
789 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
793 * IO to pool_dev remaps to the pool target's data_dev.
795 * If the whole block of data is being overwritten, we can issue the
796 * bio immediately. Otherwise we use kcopyd to clone the data first.
798 if (io_overwrites_block(pool, bio)) {
799 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
801 h->overwrite_mapping = m;
803 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
804 inc_all_io_entry(pool, bio);
805 remap_and_issue(tc, bio, data_dest);
807 struct dm_io_region from, to;
809 from.bdev = origin->bdev;
810 from.sector = data_origin * pool->sectors_per_block;
811 from.count = pool->sectors_per_block;
813 to.bdev = tc->pool_dev->bdev;
814 to.sector = data_dest * pool->sectors_per_block;
815 to.count = pool->sectors_per_block;
817 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
818 0, copy_complete, m);
820 mempool_free(m, pool->mapping_pool);
821 DMERR_LIMIT("dm_kcopyd_copy() failed");
822 cell_error(pool, cell);
827 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
828 dm_block_t data_origin, dm_block_t data_dest,
829 struct dm_bio_prison_cell *cell, struct bio *bio)
831 schedule_copy(tc, virt_block, tc->pool_dev,
832 data_origin, data_dest, cell, bio);
835 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
836 dm_block_t data_dest,
837 struct dm_bio_prison_cell *cell, struct bio *bio)
839 schedule_copy(tc, virt_block, tc->origin_dev,
840 virt_block, data_dest, cell, bio);
843 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
844 dm_block_t data_block, struct dm_bio_prison_cell *cell,
847 struct pool *pool = tc->pool;
848 struct dm_thin_new_mapping *m = get_next_mapping(pool);
853 m->virt_block = virt_block;
854 m->data_block = data_block;
858 * If the whole block of data is being overwritten or we are not
859 * zeroing pre-existing data, we can issue the bio immediately.
860 * Otherwise we use kcopyd to zero the data first.
862 if (!pool->pf.zero_new_blocks)
863 process_prepared_mapping(m);
865 else if (io_overwrites_block(pool, bio)) {
866 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
868 h->overwrite_mapping = m;
870 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
871 inc_all_io_entry(pool, bio);
872 remap_and_issue(tc, bio, data_block);
875 struct dm_io_region to;
877 to.bdev = tc->pool_dev->bdev;
878 to.sector = data_block * pool->sectors_per_block;
879 to.count = pool->sectors_per_block;
881 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
883 mempool_free(m, pool->mapping_pool);
884 DMERR_LIMIT("dm_kcopyd_zero() failed");
885 cell_error(pool, cell);
891 * A non-zero return indicates read_only or fail_io mode.
892 * Many callers don't care about the return value.
894 static int commit(struct pool *pool)
898 if (get_pool_mode(pool) != PM_WRITE)
901 r = dm_pool_commit_metadata(pool->pmd);
903 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
908 static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
912 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
913 DMWARN("%s: reached low water mark for data device: sending event.",
914 dm_device_name(pool->pool_md));
915 spin_lock_irqsave(&pool->lock, flags);
916 pool->low_water_triggered = true;
917 spin_unlock_irqrestore(&pool->lock, flags);
918 dm_table_event(pool->ti->table);
922 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
925 dm_block_t free_blocks;
926 struct pool *pool = tc->pool;
928 if (get_pool_mode(pool) != PM_WRITE)
931 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
933 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
937 check_low_water_mark(pool, free_blocks);
941 * Try to commit to see if that will free up some
948 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
950 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
955 out_of_data_space(pool);
960 r = dm_pool_alloc_data_block(pool->pmd, result);
962 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
970 * If we have run out of space, queue bios until the device is
971 * resumed, presumably after having been reloaded with more space.
973 static void retry_on_resume(struct bio *bio)
975 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
976 struct thin_c *tc = h->tc;
977 struct pool *pool = tc->pool;
980 spin_lock_irqsave(&pool->lock, flags);
981 bio_list_add(&pool->retry_on_resume_list, bio);
982 spin_unlock_irqrestore(&pool->lock, flags);
985 static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
988 struct bio_list bios;
990 bio_list_init(&bios);
991 cell_release(pool, cell, &bios);
993 while ((bio = bio_list_pop(&bios)))
994 retry_on_resume(bio);
997 static void process_discard(struct thin_c *tc, struct bio *bio)
1000 unsigned long flags;
1001 struct pool *pool = tc->pool;
1002 struct dm_bio_prison_cell *cell, *cell2;
1003 struct dm_cell_key key, key2;
1004 dm_block_t block = get_bio_block(tc, bio);
1005 struct dm_thin_lookup_result lookup_result;
1006 struct dm_thin_new_mapping *m;
1008 build_virtual_key(tc->td, block, &key);
1009 if (bio_detain(tc->pool, &key, bio, &cell))
1012 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1016 * Check nobody is fiddling with this pool block. This can
1017 * happen if someone's in the process of breaking sharing
1020 build_data_key(tc->td, lookup_result.block, &key2);
1021 if (bio_detain(tc->pool, &key2, bio, &cell2)) {
1022 cell_defer_no_holder(tc, cell);
1026 if (io_overlaps_block(pool, bio)) {
1028 * IO may still be going to the destination block. We must
1029 * quiesce before we can do the removal.
1031 m = get_next_mapping(pool);
1033 m->pass_discard = pool->pf.discard_passdown;
1034 m->definitely_not_shared = !lookup_result.shared;
1035 m->virt_block = block;
1036 m->data_block = lookup_result.block;
1041 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
1042 spin_lock_irqsave(&pool->lock, flags);
1043 list_add_tail(&m->list, &pool->prepared_discards);
1044 spin_unlock_irqrestore(&pool->lock, flags);
1048 inc_all_io_entry(pool, bio);
1049 cell_defer_no_holder(tc, cell);
1050 cell_defer_no_holder(tc, cell2);
1053 * The DM core makes sure that the discard doesn't span
1054 * a block boundary. So we submit the discard of a
1055 * partial block appropriately.
1057 if ((!lookup_result.shared) && pool->pf.discard_passdown)
1058 remap_and_issue(tc, bio, lookup_result.block);
1066 * It isn't provisioned, just forget it.
1068 cell_defer_no_holder(tc, cell);
1073 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1075 cell_defer_no_holder(tc, cell);
1081 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1082 struct dm_cell_key *key,
1083 struct dm_thin_lookup_result *lookup_result,
1084 struct dm_bio_prison_cell *cell)
1087 dm_block_t data_block;
1088 struct pool *pool = tc->pool;
1090 r = alloc_data_block(tc, &data_block);
1093 schedule_internal_copy(tc, block, lookup_result->block,
1094 data_block, cell, bio);
1098 retry_bios_on_resume(pool, cell);
1102 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1104 cell_error(pool, cell);
1109 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1111 struct dm_thin_lookup_result *lookup_result)
1113 struct dm_bio_prison_cell *cell;
1114 struct pool *pool = tc->pool;
1115 struct dm_cell_key key;
1118 * If cell is already occupied, then sharing is already in the process
1119 * of being broken so we have nothing further to do here.
1121 build_data_key(tc->td, lookup_result->block, &key);
1122 if (bio_detain(pool, &key, bio, &cell))
1125 if (bio_data_dir(bio) == WRITE && bio->bi_size)
1126 break_sharing(tc, bio, block, &key, lookup_result, cell);
1128 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1130 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1131 inc_all_io_entry(pool, bio);
1132 cell_defer_no_holder(tc, cell);
1134 remap_and_issue(tc, bio, lookup_result->block);
1138 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1139 struct dm_bio_prison_cell *cell)
1142 dm_block_t data_block;
1143 struct pool *pool = tc->pool;
1146 * Remap empty bios (flushes) immediately, without provisioning.
1148 if (!bio->bi_size) {
1149 inc_all_io_entry(pool, bio);
1150 cell_defer_no_holder(tc, cell);
1152 remap_and_issue(tc, bio, 0);
1157 * Fill read bios with zeroes and complete them immediately.
1159 if (bio_data_dir(bio) == READ) {
1161 cell_defer_no_holder(tc, cell);
1166 r = alloc_data_block(tc, &data_block);
1170 schedule_external_copy(tc, block, data_block, cell, bio);
1172 schedule_zero(tc, block, data_block, cell, bio);
1176 retry_bios_on_resume(pool, cell);
1180 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1182 cell_error(pool, cell);
1187 static void process_bio(struct thin_c *tc, struct bio *bio)
1190 struct pool *pool = tc->pool;
1191 dm_block_t block = get_bio_block(tc, bio);
1192 struct dm_bio_prison_cell *cell;
1193 struct dm_cell_key key;
1194 struct dm_thin_lookup_result lookup_result;
1197 * If cell is already occupied, then the block is already
1198 * being provisioned so we have nothing further to do here.
1200 build_virtual_key(tc->td, block, &key);
1201 if (bio_detain(pool, &key, bio, &cell))
1204 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1207 if (lookup_result.shared) {
1208 process_shared_bio(tc, bio, block, &lookup_result);
1209 cell_defer_no_holder(tc, cell); /* FIXME: pass this cell into process_shared? */
1211 inc_all_io_entry(pool, bio);
1212 cell_defer_no_holder(tc, cell);
1214 remap_and_issue(tc, bio, lookup_result.block);
1219 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1220 inc_all_io_entry(pool, bio);
1221 cell_defer_no_holder(tc, cell);
1223 remap_to_origin_and_issue(tc, bio);
1225 provision_block(tc, bio, block, cell);
1229 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1231 cell_defer_no_holder(tc, cell);
1237 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1240 int rw = bio_data_dir(bio);
1241 dm_block_t block = get_bio_block(tc, bio);
1242 struct dm_thin_lookup_result lookup_result;
1244 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1247 if (lookup_result.shared && (rw == WRITE) && bio->bi_size)
1250 inc_all_io_entry(tc->pool, bio);
1251 remap_and_issue(tc, bio, lookup_result.block);
1261 if (tc->origin_dev) {
1262 inc_all_io_entry(tc->pool, bio);
1263 remap_to_origin_and_issue(tc, bio);
1272 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1279 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1285 * FIXME: should we also commit due to size of transaction, measured in
1288 static int need_commit_due_to_time(struct pool *pool)
1290 return jiffies < pool->last_commit_jiffies ||
1291 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1294 static void process_deferred_bios(struct pool *pool)
1296 unsigned long flags;
1298 struct bio_list bios;
1300 bio_list_init(&bios);
1302 spin_lock_irqsave(&pool->lock, flags);
1303 bio_list_merge(&bios, &pool->deferred_bios);
1304 bio_list_init(&pool->deferred_bios);
1305 spin_unlock_irqrestore(&pool->lock, flags);
1307 while ((bio = bio_list_pop(&bios))) {
1308 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1309 struct thin_c *tc = h->tc;
1312 * If we've got no free new_mapping structs, and processing
1313 * this bio might require one, we pause until there are some
1314 * prepared mappings to process.
1316 if (ensure_next_mapping(pool)) {
1317 spin_lock_irqsave(&pool->lock, flags);
1318 bio_list_merge(&pool->deferred_bios, &bios);
1319 spin_unlock_irqrestore(&pool->lock, flags);
1324 if (bio->bi_rw & REQ_DISCARD)
1325 pool->process_discard(tc, bio);
1327 pool->process_bio(tc, bio);
1331 * If there are any deferred flush bios, we must commit
1332 * the metadata before issuing them.
1334 bio_list_init(&bios);
1335 spin_lock_irqsave(&pool->lock, flags);
1336 bio_list_merge(&bios, &pool->deferred_flush_bios);
1337 bio_list_init(&pool->deferred_flush_bios);
1338 spin_unlock_irqrestore(&pool->lock, flags);
1340 if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))
1344 while ((bio = bio_list_pop(&bios)))
1348 pool->last_commit_jiffies = jiffies;
1350 while ((bio = bio_list_pop(&bios)))
1351 generic_make_request(bio);
1354 static void do_worker(struct work_struct *ws)
1356 struct pool *pool = container_of(ws, struct pool, worker);
1358 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1359 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1360 process_deferred_bios(pool);
1364 * We want to commit periodically so that not too much
1365 * unwritten data builds up.
1367 static void do_waker(struct work_struct *ws)
1369 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1371 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1374 /*----------------------------------------------------------------*/
1376 static enum pool_mode get_pool_mode(struct pool *pool)
1378 return pool->pf.mode;
1381 static void set_pool_mode(struct pool *pool, enum pool_mode mode)
1385 pool->pf.mode = mode;
1389 DMERR("%s: switching pool to failure mode",
1390 dm_device_name(pool->pool_md));
1391 dm_pool_metadata_read_only(pool->pmd);
1392 pool->process_bio = process_bio_fail;
1393 pool->process_discard = process_bio_fail;
1394 pool->process_prepared_mapping = process_prepared_mapping_fail;
1395 pool->process_prepared_discard = process_prepared_discard_fail;
1399 DMERR("%s: switching pool to read-only mode",
1400 dm_device_name(pool->pool_md));
1401 r = dm_pool_abort_metadata(pool->pmd);
1403 DMERR("%s: aborting transaction failed",
1404 dm_device_name(pool->pool_md));
1405 set_pool_mode(pool, PM_FAIL);
1407 dm_pool_metadata_read_only(pool->pmd);
1408 pool->process_bio = process_bio_read_only;
1409 pool->process_discard = process_discard;
1410 pool->process_prepared_mapping = process_prepared_mapping_fail;
1411 pool->process_prepared_discard = process_prepared_discard_passdown;
1416 dm_pool_metadata_read_write(pool->pmd);
1417 pool->process_bio = process_bio;
1418 pool->process_discard = process_discard;
1419 pool->process_prepared_mapping = process_prepared_mapping;
1420 pool->process_prepared_discard = process_prepared_discard;
1425 static void set_no_free_space(struct pool *pool)
1427 unsigned long flags;
1429 spin_lock_irqsave(&pool->lock, flags);
1430 pool->no_free_space = true;
1431 spin_unlock_irqrestore(&pool->lock, flags);
1435 * Rather than calling set_pool_mode directly, use these which describe the
1436 * reason for mode degradation.
1438 static void out_of_data_space(struct pool *pool)
1440 DMERR_LIMIT("%s: no free data space available.",
1441 dm_device_name(pool->pool_md));
1442 set_no_free_space(pool);
1443 set_pool_mode(pool, PM_READ_ONLY);
1446 static void metadata_operation_failed(struct pool *pool, const char *op, int r)
1448 dm_block_t free_blocks;
1450 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
1451 dm_device_name(pool->pool_md), op, r);
1454 !dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks) &&
1456 DMERR_LIMIT("%s: no free metadata space available.",
1457 dm_device_name(pool->pool_md));
1458 set_no_free_space(pool);
1461 set_pool_mode(pool, PM_READ_ONLY);
1464 /*----------------------------------------------------------------*/
1467 * Mapping functions.
1471 * Called only while mapping a thin bio to hand it over to the workqueue.
1473 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1475 unsigned long flags;
1476 struct pool *pool = tc->pool;
1478 spin_lock_irqsave(&pool->lock, flags);
1479 bio_list_add(&pool->deferred_bios, bio);
1480 spin_unlock_irqrestore(&pool->lock, flags);
1485 static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
1487 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1490 h->shared_read_entry = NULL;
1491 h->all_io_entry = NULL;
1492 h->overwrite_mapping = NULL;
1496 * Non-blocking function called from the thin target's map function.
1498 static int thin_bio_map(struct dm_target *ti, struct bio *bio)
1501 struct thin_c *tc = ti->private;
1502 dm_block_t block = get_bio_block(tc, bio);
1503 struct dm_thin_device *td = tc->td;
1504 struct dm_thin_lookup_result result;
1505 struct dm_bio_prison_cell cell1, cell2;
1506 struct dm_bio_prison_cell *cell_result;
1507 struct dm_cell_key key;
1509 thin_hook_bio(tc, bio);
1511 if (get_pool_mode(tc->pool) == PM_FAIL) {
1513 return DM_MAPIO_SUBMITTED;
1516 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
1517 thin_defer_bio(tc, bio);
1518 return DM_MAPIO_SUBMITTED;
1521 r = dm_thin_find_block(td, block, 0, &result);
1524 * Note that we defer readahead too.
1528 if (unlikely(result.shared)) {
1530 * We have a race condition here between the
1531 * result.shared value returned by the lookup and
1532 * snapshot creation, which may cause new
1535 * To avoid this always quiesce the origin before
1536 * taking the snap. You want to do this anyway to
1537 * ensure a consistent application view
1540 * More distant ancestors are irrelevant. The
1541 * shared flag will be set in their case.
1543 thin_defer_bio(tc, bio);
1544 return DM_MAPIO_SUBMITTED;
1547 build_virtual_key(tc->td, block, &key);
1548 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
1549 return DM_MAPIO_SUBMITTED;
1551 build_data_key(tc->td, result.block, &key);
1552 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
1553 cell_defer_no_holder_no_free(tc, &cell1);
1554 return DM_MAPIO_SUBMITTED;
1557 inc_all_io_entry(tc->pool, bio);
1558 cell_defer_no_holder_no_free(tc, &cell2);
1559 cell_defer_no_holder_no_free(tc, &cell1);
1561 remap(tc, bio, result.block);
1562 return DM_MAPIO_REMAPPED;
1565 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
1567 * This block isn't provisioned, and we have no way
1568 * of doing so. Just error it.
1571 return DM_MAPIO_SUBMITTED;
1577 * In future, the failed dm_thin_find_block above could
1578 * provide the hint to load the metadata into cache.
1580 thin_defer_bio(tc, bio);
1581 return DM_MAPIO_SUBMITTED;
1585 * Must always call bio_io_error on failure.
1586 * dm_thin_find_block can fail with -EINVAL if the
1587 * pool is switched to fail-io mode.
1590 return DM_MAPIO_SUBMITTED;
1594 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1597 unsigned long flags;
1598 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1600 spin_lock_irqsave(&pt->pool->lock, flags);
1601 r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1602 spin_unlock_irqrestore(&pt->pool->lock, flags);
1605 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1606 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1612 static void __requeue_bios(struct pool *pool)
1614 bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1615 bio_list_init(&pool->retry_on_resume_list);
1618 /*----------------------------------------------------------------
1619 * Binding of control targets to a pool object
1620 *--------------------------------------------------------------*/
1621 static bool data_dev_supports_discard(struct pool_c *pt)
1623 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1625 return q && blk_queue_discard(q);
1628 static bool is_factor(sector_t block_size, uint32_t n)
1630 return !sector_div(block_size, n);
1634 * If discard_passdown was enabled verify that the data device
1635 * supports discards. Disable discard_passdown if not.
1637 static void disable_passdown_if_not_supported(struct pool_c *pt)
1639 struct pool *pool = pt->pool;
1640 struct block_device *data_bdev = pt->data_dev->bdev;
1641 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
1642 sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
1643 const char *reason = NULL;
1644 char buf[BDEVNAME_SIZE];
1646 if (!pt->adjusted_pf.discard_passdown)
1649 if (!data_dev_supports_discard(pt))
1650 reason = "discard unsupported";
1652 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
1653 reason = "max discard sectors smaller than a block";
1655 else if (data_limits->discard_granularity > block_size)
1656 reason = "discard granularity larger than a block";
1658 else if (!is_factor(block_size, data_limits->discard_granularity))
1659 reason = "discard granularity not a factor of block size";
1662 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
1663 pt->adjusted_pf.discard_passdown = false;
1667 static int bind_control_target(struct pool *pool, struct dm_target *ti)
1669 struct pool_c *pt = ti->private;
1672 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
1674 enum pool_mode old_mode = pool->pf.mode;
1675 enum pool_mode new_mode = pt->adjusted_pf.mode;
1678 * If we were in PM_FAIL mode, rollback of metadata failed. We're
1679 * not going to recover without a thin_repair. So we never let the
1680 * pool move out of the old mode. On the other hand a PM_READ_ONLY
1681 * may have been due to a lack of metadata or data space, and may
1682 * now work (ie. if the underlying devices have been resized).
1684 if (old_mode == PM_FAIL)
1685 new_mode = old_mode;
1688 pool->low_water_blocks = pt->low_water_blocks;
1689 pool->pf = pt->adjusted_pf;
1691 set_pool_mode(pool, new_mode);
1696 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1702 /*----------------------------------------------------------------
1704 *--------------------------------------------------------------*/
1705 /* Initialize pool features. */
1706 static void pool_features_init(struct pool_features *pf)
1708 pf->mode = PM_WRITE;
1709 pf->zero_new_blocks = true;
1710 pf->discard_enabled = true;
1711 pf->discard_passdown = true;
1714 static void __pool_destroy(struct pool *pool)
1716 __pool_table_remove(pool);
1718 if (dm_pool_metadata_close(pool->pmd) < 0)
1719 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1721 dm_bio_prison_destroy(pool->prison);
1722 dm_kcopyd_client_destroy(pool->copier);
1725 destroy_workqueue(pool->wq);
1727 if (pool->next_mapping)
1728 mempool_free(pool->next_mapping, pool->mapping_pool);
1729 mempool_destroy(pool->mapping_pool);
1730 dm_deferred_set_destroy(pool->shared_read_ds);
1731 dm_deferred_set_destroy(pool->all_io_ds);
1735 static struct kmem_cache *_new_mapping_cache;
1737 static struct pool *pool_create(struct mapped_device *pool_md,
1738 struct block_device *metadata_dev,
1739 unsigned long block_size,
1740 int read_only, char **error)
1745 struct dm_pool_metadata *pmd;
1746 bool format_device = read_only ? false : true;
1748 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
1750 *error = "Error creating metadata object";
1751 return (struct pool *)pmd;
1754 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1756 *error = "Error allocating memory for pool";
1757 err_p = ERR_PTR(-ENOMEM);
1762 pool->sectors_per_block = block_size;
1763 if (block_size & (block_size - 1))
1764 pool->sectors_per_block_shift = -1;
1766 pool->sectors_per_block_shift = __ffs(block_size);
1767 pool->low_water_blocks = 0;
1768 pool_features_init(&pool->pf);
1769 pool->prison = dm_bio_prison_create(PRISON_CELLS);
1770 if (!pool->prison) {
1771 *error = "Error creating pool's bio prison";
1772 err_p = ERR_PTR(-ENOMEM);
1776 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1777 if (IS_ERR(pool->copier)) {
1778 r = PTR_ERR(pool->copier);
1779 *error = "Error creating pool's kcopyd client";
1781 goto bad_kcopyd_client;
1785 * Create singlethreaded workqueue that will service all devices
1786 * that use this metadata.
1788 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1790 *error = "Error creating pool's workqueue";
1791 err_p = ERR_PTR(-ENOMEM);
1795 INIT_WORK(&pool->worker, do_worker);
1796 INIT_DELAYED_WORK(&pool->waker, do_waker);
1797 spin_lock_init(&pool->lock);
1798 bio_list_init(&pool->deferred_bios);
1799 bio_list_init(&pool->deferred_flush_bios);
1800 INIT_LIST_HEAD(&pool->prepared_mappings);
1801 INIT_LIST_HEAD(&pool->prepared_discards);
1802 pool->low_water_triggered = false;
1803 pool->no_free_space = false;
1804 bio_list_init(&pool->retry_on_resume_list);
1806 pool->shared_read_ds = dm_deferred_set_create();
1807 if (!pool->shared_read_ds) {
1808 *error = "Error creating pool's shared read deferred set";
1809 err_p = ERR_PTR(-ENOMEM);
1810 goto bad_shared_read_ds;
1813 pool->all_io_ds = dm_deferred_set_create();
1814 if (!pool->all_io_ds) {
1815 *error = "Error creating pool's all io deferred set";
1816 err_p = ERR_PTR(-ENOMEM);
1820 pool->next_mapping = NULL;
1821 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
1822 _new_mapping_cache);
1823 if (!pool->mapping_pool) {
1824 *error = "Error creating pool's mapping mempool";
1825 err_p = ERR_PTR(-ENOMEM);
1826 goto bad_mapping_pool;
1829 pool->ref_count = 1;
1830 pool->last_commit_jiffies = jiffies;
1831 pool->pool_md = pool_md;
1832 pool->md_dev = metadata_dev;
1833 __pool_table_insert(pool);
1838 dm_deferred_set_destroy(pool->all_io_ds);
1840 dm_deferred_set_destroy(pool->shared_read_ds);
1842 destroy_workqueue(pool->wq);
1844 dm_kcopyd_client_destroy(pool->copier);
1846 dm_bio_prison_destroy(pool->prison);
1850 if (dm_pool_metadata_close(pmd))
1851 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1856 static void __pool_inc(struct pool *pool)
1858 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1862 static void __pool_dec(struct pool *pool)
1864 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1865 BUG_ON(!pool->ref_count);
1866 if (!--pool->ref_count)
1867 __pool_destroy(pool);
1870 static struct pool *__pool_find(struct mapped_device *pool_md,
1871 struct block_device *metadata_dev,
1872 unsigned long block_size, int read_only,
1873 char **error, int *created)
1875 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1878 if (pool->pool_md != pool_md) {
1879 *error = "metadata device already in use by a pool";
1880 return ERR_PTR(-EBUSY);
1885 pool = __pool_table_lookup(pool_md);
1887 if (pool->md_dev != metadata_dev) {
1888 *error = "different pool cannot replace a pool";
1889 return ERR_PTR(-EINVAL);
1894 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
1902 /*----------------------------------------------------------------
1903 * Pool target methods
1904 *--------------------------------------------------------------*/
1905 static void pool_dtr(struct dm_target *ti)
1907 struct pool_c *pt = ti->private;
1909 mutex_lock(&dm_thin_pool_table.mutex);
1911 unbind_control_target(pt->pool, ti);
1912 __pool_dec(pt->pool);
1913 dm_put_device(ti, pt->metadata_dev);
1914 dm_put_device(ti, pt->data_dev);
1917 mutex_unlock(&dm_thin_pool_table.mutex);
1920 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
1921 struct dm_target *ti)
1925 const char *arg_name;
1927 static struct dm_arg _args[] = {
1928 {0, 3, "Invalid number of pool feature arguments"},
1932 * No feature arguments supplied.
1937 r = dm_read_arg_group(_args, as, &argc, &ti->error);
1941 while (argc && !r) {
1942 arg_name = dm_shift_arg(as);
1945 if (!strcasecmp(arg_name, "skip_block_zeroing"))
1946 pf->zero_new_blocks = false;
1948 else if (!strcasecmp(arg_name, "ignore_discard"))
1949 pf->discard_enabled = false;
1951 else if (!strcasecmp(arg_name, "no_discard_passdown"))
1952 pf->discard_passdown = false;
1954 else if (!strcasecmp(arg_name, "read_only"))
1955 pf->mode = PM_READ_ONLY;
1958 ti->error = "Unrecognised pool feature requested";
1967 static void metadata_low_callback(void *context)
1969 struct pool *pool = context;
1971 DMWARN("%s: reached low water mark for metadata device: sending event.",
1972 dm_device_name(pool->pool_md));
1974 dm_table_event(pool->ti->table);
1977 static sector_t get_metadata_dev_size(struct block_device *bdev)
1979 sector_t metadata_dev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
1980 char buffer[BDEVNAME_SIZE];
1982 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) {
1983 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1984 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
1985 metadata_dev_size = THIN_METADATA_MAX_SECTORS_WARNING;
1988 return metadata_dev_size;
1991 static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
1993 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
1995 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
1997 return metadata_dev_size;
2001 * When a metadata threshold is crossed a dm event is triggered, and
2002 * userland should respond by growing the metadata device. We could let
2003 * userland set the threshold, like we do with the data threshold, but I'm
2004 * not sure they know enough to do this well.
2006 static dm_block_t calc_metadata_threshold(struct pool_c *pt)
2009 * 4M is ample for all ops with the possible exception of thin
2010 * device deletion which is harmless if it fails (just retry the
2011 * delete after you've grown the device).
2013 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
2014 return min((dm_block_t)1024ULL /* 4M */, quarter);
2018 * thin-pool <metadata dev> <data dev>
2019 * <data block size (sectors)>
2020 * <low water mark (blocks)>
2021 * [<#feature args> [<arg>]*]
2023 * Optional feature arguments are:
2024 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
2025 * ignore_discard: disable discard
2026 * no_discard_passdown: don't pass discards down to the data device
2028 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
2030 int r, pool_created = 0;
2033 struct pool_features pf;
2034 struct dm_arg_set as;
2035 struct dm_dev *data_dev;
2036 unsigned long block_size;
2037 dm_block_t low_water_blocks;
2038 struct dm_dev *metadata_dev;
2039 fmode_t metadata_mode;
2042 * FIXME Remove validation from scope of lock.
2044 mutex_lock(&dm_thin_pool_table.mutex);
2047 ti->error = "Invalid argument count";
2056 * Set default pool features.
2058 pool_features_init(&pf);
2060 dm_consume_args(&as, 4);
2061 r = parse_pool_features(&as, &pf, ti);
2065 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
2066 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
2068 ti->error = "Error opening metadata block device";
2073 * Run for the side-effect of possibly issuing a warning if the
2074 * device is too big.
2076 (void) get_metadata_dev_size(metadata_dev->bdev);
2078 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
2080 ti->error = "Error getting data device";
2084 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
2085 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
2086 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
2087 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
2088 ti->error = "Invalid block size";
2093 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
2094 ti->error = "Invalid low water mark";
2099 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
2105 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
2106 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
2113 * 'pool_created' reflects whether this is the first table load.
2114 * Top level discard support is not allowed to be changed after
2115 * initial load. This would require a pool reload to trigger thin
2118 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
2119 ti->error = "Discard support cannot be disabled once enabled";
2121 goto out_flags_changed;
2126 pt->metadata_dev = metadata_dev;
2127 pt->data_dev = data_dev;
2128 pt->low_water_blocks = low_water_blocks;
2129 pt->adjusted_pf = pt->requested_pf = pf;
2130 ti->num_flush_bios = 1;
2133 * Only need to enable discards if the pool should pass
2134 * them down to the data device. The thin device's discard
2135 * processing will cause mappings to be removed from the btree.
2137 ti->discard_zeroes_data_unsupported = true;
2138 if (pf.discard_enabled && pf.discard_passdown) {
2139 ti->num_discard_bios = 1;
2142 * Setting 'discards_supported' circumvents the normal
2143 * stacking of discard limits (this keeps the pool and
2144 * thin devices' discard limits consistent).
2146 ti->discards_supported = true;
2150 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
2151 calc_metadata_threshold(pt),
2152 metadata_low_callback,
2157 pt->callbacks.congested_fn = pool_is_congested;
2158 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2160 mutex_unlock(&dm_thin_pool_table.mutex);
2169 dm_put_device(ti, data_dev);
2171 dm_put_device(ti, metadata_dev);
2173 mutex_unlock(&dm_thin_pool_table.mutex);
2178 static int pool_map(struct dm_target *ti, struct bio *bio)
2181 struct pool_c *pt = ti->private;
2182 struct pool *pool = pt->pool;
2183 unsigned long flags;
2186 * As this is a singleton target, ti->begin is always zero.
2188 spin_lock_irqsave(&pool->lock, flags);
2189 bio->bi_bdev = pt->data_dev->bdev;
2190 r = DM_MAPIO_REMAPPED;
2191 spin_unlock_irqrestore(&pool->lock, flags);
2196 static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
2199 struct pool_c *pt = ti->private;
2200 struct pool *pool = pt->pool;
2201 sector_t data_size = ti->len;
2202 dm_block_t sb_data_size;
2204 *need_commit = false;
2206 (void) sector_div(data_size, pool->sectors_per_block);
2208 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2210 DMERR("%s: failed to retrieve data device size",
2211 dm_device_name(pool->pool_md));
2215 if (data_size < sb_data_size) {
2216 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
2217 dm_device_name(pool->pool_md),
2218 (unsigned long long)data_size, sb_data_size);
2221 } else if (data_size > sb_data_size) {
2223 DMINFO("%s: growing the data device from %llu to %llu blocks",
2224 dm_device_name(pool->pool_md),
2225 sb_data_size, (unsigned long long)data_size);
2226 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2228 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
2232 *need_commit = true;
2238 static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
2241 struct pool_c *pt = ti->private;
2242 struct pool *pool = pt->pool;
2243 dm_block_t metadata_dev_size, sb_metadata_dev_size;
2245 *need_commit = false;
2247 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
2249 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
2251 DMERR("%s: failed to retrieve metadata device size",
2252 dm_device_name(pool->pool_md));
2256 if (metadata_dev_size < sb_metadata_dev_size) {
2257 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
2258 dm_device_name(pool->pool_md),
2259 metadata_dev_size, sb_metadata_dev_size);
2262 } else if (metadata_dev_size > sb_metadata_dev_size) {
2263 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
2264 dm_device_name(pool->pool_md),
2265 sb_metadata_dev_size, metadata_dev_size);
2266 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
2268 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
2272 *need_commit = true;
2279 * Retrieves the number of blocks of the data device from
2280 * the superblock and compares it to the actual device size,
2281 * thus resizing the data device in case it has grown.
2283 * This both copes with opening preallocated data devices in the ctr
2284 * being followed by a resume
2286 * calling the resume method individually after userspace has
2287 * grown the data device in reaction to a table event.
2289 static int pool_preresume(struct dm_target *ti)
2292 bool need_commit1, need_commit2;
2293 struct pool_c *pt = ti->private;
2294 struct pool *pool = pt->pool;
2297 * Take control of the pool object.
2299 r = bind_control_target(pool, ti);
2303 r = maybe_resize_data_dev(ti, &need_commit1);
2307 r = maybe_resize_metadata_dev(ti, &need_commit2);
2311 if (need_commit1 || need_commit2)
2312 (void) commit(pool);
2317 static void pool_resume(struct dm_target *ti)
2319 struct pool_c *pt = ti->private;
2320 struct pool *pool = pt->pool;
2321 unsigned long flags;
2323 spin_lock_irqsave(&pool->lock, flags);
2324 pool->low_water_triggered = false;
2325 pool->no_free_space = false;
2326 __requeue_bios(pool);
2327 spin_unlock_irqrestore(&pool->lock, flags);
2329 do_waker(&pool->waker.work);
2332 static void pool_postsuspend(struct dm_target *ti)
2334 struct pool_c *pt = ti->private;
2335 struct pool *pool = pt->pool;
2337 cancel_delayed_work(&pool->waker);
2338 flush_workqueue(pool->wq);
2339 (void) commit(pool);
2342 static int check_arg_count(unsigned argc, unsigned args_required)
2344 if (argc != args_required) {
2345 DMWARN("Message received with %u arguments instead of %u.",
2346 argc, args_required);
2353 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2355 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2356 *dev_id <= MAX_DEV_ID)
2360 DMWARN("Message received with invalid device id: %s", arg);
2365 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2370 r = check_arg_count(argc, 2);
2374 r = read_dev_id(argv[1], &dev_id, 1);
2378 r = dm_pool_create_thin(pool->pmd, dev_id);
2380 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2388 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2391 dm_thin_id origin_dev_id;
2394 r = check_arg_count(argc, 3);
2398 r = read_dev_id(argv[1], &dev_id, 1);
2402 r = read_dev_id(argv[2], &origin_dev_id, 1);
2406 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2408 DMWARN("Creation of new snapshot %s of device %s failed.",
2416 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2421 r = check_arg_count(argc, 2);
2425 r = read_dev_id(argv[1], &dev_id, 1);
2429 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2431 DMWARN("Deletion of thin device %s failed.", argv[1]);
2436 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2438 dm_thin_id old_id, new_id;
2441 r = check_arg_count(argc, 3);
2445 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2446 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2450 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2451 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2455 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2457 DMWARN("Failed to change transaction id from %s to %s.",
2465 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2469 r = check_arg_count(argc, 1);
2473 (void) commit(pool);
2475 r = dm_pool_reserve_metadata_snap(pool->pmd);
2477 DMWARN("reserve_metadata_snap message failed.");
2482 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2486 r = check_arg_count(argc, 1);
2490 r = dm_pool_release_metadata_snap(pool->pmd);
2492 DMWARN("release_metadata_snap message failed.");
2498 * Messages supported:
2499 * create_thin <dev_id>
2500 * create_snap <dev_id> <origin_id>
2502 * trim <dev_id> <new_size_in_sectors>
2503 * set_transaction_id <current_trans_id> <new_trans_id>
2504 * reserve_metadata_snap
2505 * release_metadata_snap
2507 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2510 struct pool_c *pt = ti->private;
2511 struct pool *pool = pt->pool;
2513 if (!strcasecmp(argv[0], "create_thin"))
2514 r = process_create_thin_mesg(argc, argv, pool);
2516 else if (!strcasecmp(argv[0], "create_snap"))
2517 r = process_create_snap_mesg(argc, argv, pool);
2519 else if (!strcasecmp(argv[0], "delete"))
2520 r = process_delete_mesg(argc, argv, pool);
2522 else if (!strcasecmp(argv[0], "set_transaction_id"))
2523 r = process_set_transaction_id_mesg(argc, argv, pool);
2525 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
2526 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
2528 else if (!strcasecmp(argv[0], "release_metadata_snap"))
2529 r = process_release_metadata_snap_mesg(argc, argv, pool);
2532 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2535 (void) commit(pool);
2540 static void emit_flags(struct pool_features *pf, char *result,
2541 unsigned sz, unsigned maxlen)
2543 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
2544 !pf->discard_passdown + (pf->mode == PM_READ_ONLY);
2545 DMEMIT("%u ", count);
2547 if (!pf->zero_new_blocks)
2548 DMEMIT("skip_block_zeroing ");
2550 if (!pf->discard_enabled)
2551 DMEMIT("ignore_discard ");
2553 if (!pf->discard_passdown)
2554 DMEMIT("no_discard_passdown ");
2556 if (pf->mode == PM_READ_ONLY)
2557 DMEMIT("read_only ");
2562 * <transaction id> <used metadata sectors>/<total metadata sectors>
2563 * <used data sectors>/<total data sectors> <held metadata root>
2565 static void pool_status(struct dm_target *ti, status_type_t type,
2566 unsigned status_flags, char *result, unsigned maxlen)
2570 uint64_t transaction_id;
2571 dm_block_t nr_free_blocks_data;
2572 dm_block_t nr_free_blocks_metadata;
2573 dm_block_t nr_blocks_data;
2574 dm_block_t nr_blocks_metadata;
2575 dm_block_t held_root;
2576 char buf[BDEVNAME_SIZE];
2577 char buf2[BDEVNAME_SIZE];
2578 struct pool_c *pt = ti->private;
2579 struct pool *pool = pt->pool;
2582 case STATUSTYPE_INFO:
2583 if (get_pool_mode(pool) == PM_FAIL) {
2588 /* Commit to ensure statistics aren't out-of-date */
2589 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
2590 (void) commit(pool);
2592 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
2594 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
2595 dm_device_name(pool->pool_md), r);
2599 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
2601 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
2602 dm_device_name(pool->pool_md), r);
2606 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2608 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
2609 dm_device_name(pool->pool_md), r);
2613 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
2615 DMERR("%s: dm_pool_get_free_block_count returned %d",
2616 dm_device_name(pool->pool_md), r);
2620 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2622 DMERR("%s: dm_pool_get_data_dev_size returned %d",
2623 dm_device_name(pool->pool_md), r);
2627 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
2629 DMERR("%s: dm_pool_get_metadata_snap returned %d",
2630 dm_device_name(pool->pool_md), r);
2634 DMEMIT("%llu %llu/%llu %llu/%llu ",
2635 (unsigned long long)transaction_id,
2636 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2637 (unsigned long long)nr_blocks_metadata,
2638 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2639 (unsigned long long)nr_blocks_data);
2642 DMEMIT("%llu ", held_root);
2646 if (pool->pf.mode == PM_READ_ONLY)
2651 if (!pool->pf.discard_enabled)
2652 DMEMIT("ignore_discard");
2653 else if (pool->pf.discard_passdown)
2654 DMEMIT("discard_passdown");
2656 DMEMIT("no_discard_passdown");
2660 case STATUSTYPE_TABLE:
2661 DMEMIT("%s %s %lu %llu ",
2662 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2663 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2664 (unsigned long)pool->sectors_per_block,
2665 (unsigned long long)pt->low_water_blocks);
2666 emit_flags(&pt->requested_pf, result, sz, maxlen);
2675 static int pool_iterate_devices(struct dm_target *ti,
2676 iterate_devices_callout_fn fn, void *data)
2678 struct pool_c *pt = ti->private;
2680 return fn(ti, pt->data_dev, 0, ti->len, data);
2683 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2684 struct bio_vec *biovec, int max_size)
2686 struct pool_c *pt = ti->private;
2687 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2689 if (!q->merge_bvec_fn)
2692 bvm->bi_bdev = pt->data_dev->bdev;
2694 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2697 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
2699 struct pool *pool = pt->pool;
2700 struct queue_limits *data_limits;
2702 limits->max_discard_sectors = pool->sectors_per_block;
2705 * discard_granularity is just a hint, and not enforced.
2707 if (pt->adjusted_pf.discard_passdown) {
2708 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
2709 limits->discard_granularity = data_limits->discard_granularity;
2711 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
2714 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2716 struct pool_c *pt = ti->private;
2717 struct pool *pool = pt->pool;
2718 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
2721 * If the system-determined stacked limits are compatible with the
2722 * pool's blocksize (io_opt is a factor) do not override them.
2724 if (io_opt_sectors < pool->sectors_per_block ||
2725 do_div(io_opt_sectors, pool->sectors_per_block)) {
2726 blk_limits_io_min(limits, 0);
2727 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2731 * pt->adjusted_pf is a staging area for the actual features to use.
2732 * They get transferred to the live pool in bind_control_target()
2733 * called from pool_preresume().
2735 if (!pt->adjusted_pf.discard_enabled) {
2737 * Must explicitly disallow stacking discard limits otherwise the
2738 * block layer will stack them if pool's data device has support.
2739 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
2740 * user to see that, so make sure to set all discard limits to 0.
2742 limits->discard_granularity = 0;
2746 disable_passdown_if_not_supported(pt);
2748 set_discard_limits(pt, limits);
2751 static struct target_type pool_target = {
2752 .name = "thin-pool",
2753 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2754 DM_TARGET_IMMUTABLE,
2755 .version = {1, 9, 0},
2756 .module = THIS_MODULE,
2760 .postsuspend = pool_postsuspend,
2761 .preresume = pool_preresume,
2762 .resume = pool_resume,
2763 .message = pool_message,
2764 .status = pool_status,
2765 .merge = pool_merge,
2766 .iterate_devices = pool_iterate_devices,
2767 .io_hints = pool_io_hints,
2770 /*----------------------------------------------------------------
2771 * Thin target methods
2772 *--------------------------------------------------------------*/
2773 static void thin_dtr(struct dm_target *ti)
2775 struct thin_c *tc = ti->private;
2777 mutex_lock(&dm_thin_pool_table.mutex);
2779 __pool_dec(tc->pool);
2780 dm_pool_close_thin_device(tc->td);
2781 dm_put_device(ti, tc->pool_dev);
2783 dm_put_device(ti, tc->origin_dev);
2786 mutex_unlock(&dm_thin_pool_table.mutex);
2790 * Thin target parameters:
2792 * <pool_dev> <dev_id> [origin_dev]
2794 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2795 * dev_id: the internal device identifier
2796 * origin_dev: a device external to the pool that should act as the origin
2798 * If the pool device has discards disabled, they get disabled for the thin
2801 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2805 struct dm_dev *pool_dev, *origin_dev;
2806 struct mapped_device *pool_md;
2808 mutex_lock(&dm_thin_pool_table.mutex);
2810 if (argc != 2 && argc != 3) {
2811 ti->error = "Invalid argument count";
2816 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2818 ti->error = "Out of memory";
2824 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
2826 ti->error = "Error opening origin device";
2827 goto bad_origin_dev;
2829 tc->origin_dev = origin_dev;
2832 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2834 ti->error = "Error opening pool device";
2837 tc->pool_dev = pool_dev;
2839 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2840 ti->error = "Invalid device id";
2845 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2847 ti->error = "Couldn't get pool mapped device";
2852 tc->pool = __pool_table_lookup(pool_md);
2854 ti->error = "Couldn't find pool object";
2856 goto bad_pool_lookup;
2858 __pool_inc(tc->pool);
2860 if (get_pool_mode(tc->pool) == PM_FAIL) {
2861 ti->error = "Couldn't open thin device, Pool is in fail mode";
2865 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
2867 ti->error = "Couldn't open thin internal device";
2871 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
2875 ti->num_flush_bios = 1;
2876 ti->flush_supported = true;
2877 ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
2879 /* In case the pool supports discards, pass them on. */
2880 ti->discard_zeroes_data_unsupported = true;
2881 if (tc->pool->pf.discard_enabled) {
2882 ti->discards_supported = true;
2883 ti->num_discard_bios = 1;
2884 /* Discard bios must be split on a block boundary */
2885 ti->split_discard_bios = true;
2890 mutex_unlock(&dm_thin_pool_table.mutex);
2895 __pool_dec(tc->pool);
2899 dm_put_device(ti, tc->pool_dev);
2902 dm_put_device(ti, tc->origin_dev);
2906 mutex_unlock(&dm_thin_pool_table.mutex);
2911 static int thin_map(struct dm_target *ti, struct bio *bio)
2913 bio->bi_sector = dm_target_offset(ti, bio->bi_sector);
2915 return thin_bio_map(ti, bio);
2918 static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
2920 unsigned long flags;
2921 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2922 struct list_head work;
2923 struct dm_thin_new_mapping *m, *tmp;
2924 struct pool *pool = h->tc->pool;
2926 if (h->shared_read_entry) {
2927 INIT_LIST_HEAD(&work);
2928 dm_deferred_entry_dec(h->shared_read_entry, &work);
2930 spin_lock_irqsave(&pool->lock, flags);
2931 list_for_each_entry_safe(m, tmp, &work, list) {
2934 __maybe_add_mapping(m);
2936 spin_unlock_irqrestore(&pool->lock, flags);
2939 if (h->all_io_entry) {
2940 INIT_LIST_HEAD(&work);
2941 dm_deferred_entry_dec(h->all_io_entry, &work);
2942 if (!list_empty(&work)) {
2943 spin_lock_irqsave(&pool->lock, flags);
2944 list_for_each_entry_safe(m, tmp, &work, list)
2945 list_add_tail(&m->list, &pool->prepared_discards);
2946 spin_unlock_irqrestore(&pool->lock, flags);
2954 static void thin_postsuspend(struct dm_target *ti)
2956 if (dm_noflush_suspending(ti))
2957 requeue_io((struct thin_c *)ti->private);
2961 * <nr mapped sectors> <highest mapped sector>
2963 static void thin_status(struct dm_target *ti, status_type_t type,
2964 unsigned status_flags, char *result, unsigned maxlen)
2968 dm_block_t mapped, highest;
2969 char buf[BDEVNAME_SIZE];
2970 struct thin_c *tc = ti->private;
2972 if (get_pool_mode(tc->pool) == PM_FAIL) {
2981 case STATUSTYPE_INFO:
2982 r = dm_thin_get_mapped_count(tc->td, &mapped);
2984 DMERR("dm_thin_get_mapped_count returned %d", r);
2988 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
2990 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
2994 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
2996 DMEMIT("%llu", ((highest + 1) *
2997 tc->pool->sectors_per_block) - 1);
3002 case STATUSTYPE_TABLE:
3004 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
3005 (unsigned long) tc->dev_id);
3007 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
3018 static int thin_iterate_devices(struct dm_target *ti,
3019 iterate_devices_callout_fn fn, void *data)
3022 struct thin_c *tc = ti->private;
3023 struct pool *pool = tc->pool;
3026 * We can't call dm_pool_get_data_dev_size() since that blocks. So
3027 * we follow a more convoluted path through to the pool's target.
3030 return 0; /* nothing is bound */
3032 blocks = pool->ti->len;
3033 (void) sector_div(blocks, pool->sectors_per_block);
3035 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
3040 static struct target_type thin_target = {
3042 .version = {1, 9, 0},
3043 .module = THIS_MODULE,
3047 .end_io = thin_endio,
3048 .postsuspend = thin_postsuspend,
3049 .status = thin_status,
3050 .iterate_devices = thin_iterate_devices,
3053 /*----------------------------------------------------------------*/
3055 static int __init dm_thin_init(void)
3061 r = dm_register_target(&thin_target);
3065 r = dm_register_target(&pool_target);
3067 goto bad_pool_target;
3071 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
3072 if (!_new_mapping_cache)
3073 goto bad_new_mapping_cache;
3077 bad_new_mapping_cache:
3078 dm_unregister_target(&pool_target);
3080 dm_unregister_target(&thin_target);
3085 static void dm_thin_exit(void)
3087 dm_unregister_target(&thin_target);
3088 dm_unregister_target(&pool_target);
3090 kmem_cache_destroy(_new_mapping_cache);
3093 module_init(dm_thin_init);
3094 module_exit(dm_thin_exit);
3096 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
3097 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3098 MODULE_LICENSE("GPL");