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 unsigned low_water_triggered:1; /* A dm event has been sent */
167 unsigned 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 set_pool_mode(struct pool *pool, enum pool_mode mode);
204 * Target context for a pool.
207 struct dm_target *ti;
209 struct dm_dev *data_dev;
210 struct dm_dev *metadata_dev;
211 struct dm_target_callbacks callbacks;
213 dm_block_t low_water_blocks;
214 struct pool_features requested_pf; /* Features requested during table load */
215 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
219 * Target context for a thin.
222 struct dm_dev *pool_dev;
223 struct dm_dev *origin_dev;
227 struct dm_thin_device *td;
230 /*----------------------------------------------------------------*/
233 * wake_worker() is used when new work is queued and when pool_resume is
234 * ready to continue deferred IO processing.
236 static void wake_worker(struct pool *pool)
238 queue_work(pool->wq, &pool->worker);
241 /*----------------------------------------------------------------*/
243 static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
244 struct dm_bio_prison_cell **cell_result)
247 struct dm_bio_prison_cell *cell_prealloc;
250 * Allocate a cell from the prison's mempool.
251 * This might block but it can't fail.
253 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
255 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
258 * We reused an old cell; we can get rid of
261 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
266 static void cell_release(struct pool *pool,
267 struct dm_bio_prison_cell *cell,
268 struct bio_list *bios)
270 dm_cell_release(pool->prison, cell, bios);
271 dm_bio_prison_free_cell(pool->prison, cell);
274 static void cell_release_no_holder(struct pool *pool,
275 struct dm_bio_prison_cell *cell,
276 struct bio_list *bios)
278 dm_cell_release_no_holder(pool->prison, cell, bios);
279 dm_bio_prison_free_cell(pool->prison, cell);
282 static void cell_defer_no_holder_no_free(struct thin_c *tc,
283 struct dm_bio_prison_cell *cell)
285 struct pool *pool = tc->pool;
288 spin_lock_irqsave(&pool->lock, flags);
289 dm_cell_release_no_holder(pool->prison, cell, &pool->deferred_bios);
290 spin_unlock_irqrestore(&pool->lock, flags);
295 static void cell_error(struct pool *pool,
296 struct dm_bio_prison_cell *cell)
298 dm_cell_error(pool->prison, cell);
299 dm_bio_prison_free_cell(pool->prison, cell);
302 /*----------------------------------------------------------------*/
305 * A global list of pools that uses a struct mapped_device as a key.
307 static struct dm_thin_pool_table {
309 struct list_head pools;
310 } dm_thin_pool_table;
312 static void pool_table_init(void)
314 mutex_init(&dm_thin_pool_table.mutex);
315 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
318 static void __pool_table_insert(struct pool *pool)
320 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
321 list_add(&pool->list, &dm_thin_pool_table.pools);
324 static void __pool_table_remove(struct pool *pool)
326 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
327 list_del(&pool->list);
330 static struct pool *__pool_table_lookup(struct mapped_device *md)
332 struct pool *pool = NULL, *tmp;
334 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
336 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
337 if (tmp->pool_md == md) {
346 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
348 struct pool *pool = NULL, *tmp;
350 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
352 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
353 if (tmp->md_dev == md_dev) {
362 /*----------------------------------------------------------------*/
364 struct dm_thin_endio_hook {
366 struct dm_deferred_entry *shared_read_entry;
367 struct dm_deferred_entry *all_io_entry;
368 struct dm_thin_new_mapping *overwrite_mapping;
371 static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
374 struct bio_list bios;
376 bio_list_init(&bios);
377 bio_list_merge(&bios, master);
378 bio_list_init(master);
380 while ((bio = bio_list_pop(&bios))) {
381 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
384 bio_endio(bio, DM_ENDIO_REQUEUE);
386 bio_list_add(master, bio);
390 static void requeue_io(struct thin_c *tc)
392 struct pool *pool = tc->pool;
395 spin_lock_irqsave(&pool->lock, flags);
396 __requeue_bio_list(tc, &pool->deferred_bios);
397 __requeue_bio_list(tc, &pool->retry_on_resume_list);
398 spin_unlock_irqrestore(&pool->lock, flags);
402 * This section of code contains the logic for processing a thin device's IO.
403 * Much of the code depends on pool object resources (lists, workqueues, etc)
404 * but most is exclusively called from the thin target rather than the thin-pool
408 static bool block_size_is_power_of_two(struct pool *pool)
410 return pool->sectors_per_block_shift >= 0;
413 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
415 struct pool *pool = tc->pool;
416 sector_t block_nr = bio->bi_sector;
418 if (block_size_is_power_of_two(pool))
419 block_nr >>= pool->sectors_per_block_shift;
421 (void) sector_div(block_nr, pool->sectors_per_block);
426 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
428 struct pool *pool = tc->pool;
429 sector_t bi_sector = bio->bi_sector;
431 bio->bi_bdev = tc->pool_dev->bdev;
432 if (block_size_is_power_of_two(pool))
433 bio->bi_sector = (block << pool->sectors_per_block_shift) |
434 (bi_sector & (pool->sectors_per_block - 1));
436 bio->bi_sector = (block * pool->sectors_per_block) +
437 sector_div(bi_sector, pool->sectors_per_block);
440 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
442 bio->bi_bdev = tc->origin_dev->bdev;
445 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
447 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
448 dm_thin_changed_this_transaction(tc->td);
451 static void inc_all_io_entry(struct pool *pool, struct bio *bio)
453 struct dm_thin_endio_hook *h;
455 if (bio->bi_rw & REQ_DISCARD)
458 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
459 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
462 static void issue(struct thin_c *tc, struct bio *bio)
464 struct pool *pool = tc->pool;
467 if (!bio_triggers_commit(tc, bio)) {
468 generic_make_request(bio);
473 * Complete bio with an error if earlier I/O caused changes to
474 * the metadata that can't be committed e.g, due to I/O errors
475 * on the metadata device.
477 if (dm_thin_aborted_changes(tc->td)) {
483 * Batch together any bios that trigger commits and then issue a
484 * single commit for them in process_deferred_bios().
486 spin_lock_irqsave(&pool->lock, flags);
487 bio_list_add(&pool->deferred_flush_bios, bio);
488 spin_unlock_irqrestore(&pool->lock, flags);
491 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
493 remap_to_origin(tc, bio);
497 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
500 remap(tc, bio, block);
504 /*----------------------------------------------------------------*/
507 * Bio endio functions.
509 struct dm_thin_new_mapping {
510 struct list_head list;
514 unsigned pass_discard:1;
517 dm_block_t virt_block;
518 dm_block_t data_block;
519 struct dm_bio_prison_cell *cell, *cell2;
523 * If the bio covers the whole area of a block then we can avoid
524 * zeroing or copying. Instead this bio is hooked. The bio will
525 * still be in the cell, so care has to be taken to avoid issuing
529 bio_end_io_t *saved_bi_end_io;
532 static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
534 struct pool *pool = m->tc->pool;
536 if (m->quiesced && m->prepared) {
537 list_add(&m->list, &pool->prepared_mappings);
542 static void copy_complete(int read_err, unsigned long write_err, void *context)
545 struct dm_thin_new_mapping *m = context;
546 struct pool *pool = m->tc->pool;
548 m->err = read_err || write_err ? -EIO : 0;
550 spin_lock_irqsave(&pool->lock, flags);
552 __maybe_add_mapping(m);
553 spin_unlock_irqrestore(&pool->lock, flags);
556 static void overwrite_endio(struct bio *bio, int err)
559 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
560 struct dm_thin_new_mapping *m = h->overwrite_mapping;
561 struct pool *pool = m->tc->pool;
565 spin_lock_irqsave(&pool->lock, flags);
567 __maybe_add_mapping(m);
568 spin_unlock_irqrestore(&pool->lock, flags);
571 /*----------------------------------------------------------------*/
578 * Prepared mapping jobs.
582 * This sends the bios in the cell back to the deferred_bios list.
584 static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
586 struct pool *pool = tc->pool;
589 spin_lock_irqsave(&pool->lock, flags);
590 cell_release(pool, cell, &pool->deferred_bios);
591 spin_unlock_irqrestore(&tc->pool->lock, flags);
597 * Same as cell_defer above, except it omits the original holder of the cell.
599 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
601 struct pool *pool = tc->pool;
604 spin_lock_irqsave(&pool->lock, flags);
605 cell_release_no_holder(pool, cell, &pool->deferred_bios);
606 spin_unlock_irqrestore(&pool->lock, flags);
611 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
614 m->bio->bi_end_io = m->saved_bi_end_io;
615 cell_error(m->tc->pool, m->cell);
617 mempool_free(m, m->tc->pool->mapping_pool);
620 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
622 struct thin_c *tc = m->tc;
623 struct pool *pool = tc->pool;
629 bio->bi_end_io = m->saved_bi_end_io;
632 cell_error(pool, m->cell);
637 * Commit the prepared block into the mapping btree.
638 * Any I/O for this block arriving after this point will get
639 * remapped to it directly.
641 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
643 DMERR_LIMIT("dm_thin_insert_block() failed");
644 cell_error(pool, m->cell);
649 * Release any bios held while the block was being provisioned.
650 * If we are processing a write bio that completely covers the block,
651 * we already processed it so can ignore it now when processing
652 * the bios in the cell.
655 cell_defer_no_holder(tc, m->cell);
658 cell_defer(tc, m->cell);
662 mempool_free(m, pool->mapping_pool);
665 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
667 struct thin_c *tc = m->tc;
669 bio_io_error(m->bio);
670 cell_defer_no_holder(tc, m->cell);
671 cell_defer_no_holder(tc, m->cell2);
672 mempool_free(m, tc->pool->mapping_pool);
675 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
677 struct thin_c *tc = m->tc;
679 inc_all_io_entry(tc->pool, m->bio);
680 cell_defer_no_holder(tc, m->cell);
681 cell_defer_no_holder(tc, m->cell2);
684 remap_and_issue(tc, m->bio, m->data_block);
686 bio_endio(m->bio, 0);
688 mempool_free(m, tc->pool->mapping_pool);
691 static void process_prepared_discard(struct dm_thin_new_mapping *m)
694 struct thin_c *tc = m->tc;
696 r = dm_thin_remove_block(tc->td, m->virt_block);
698 DMERR_LIMIT("dm_thin_remove_block() failed");
700 process_prepared_discard_passdown(m);
703 static void process_prepared(struct pool *pool, struct list_head *head,
704 process_mapping_fn *fn)
707 struct list_head maps;
708 struct dm_thin_new_mapping *m, *tmp;
710 INIT_LIST_HEAD(&maps);
711 spin_lock_irqsave(&pool->lock, flags);
712 list_splice_init(head, &maps);
713 spin_unlock_irqrestore(&pool->lock, flags);
715 list_for_each_entry_safe(m, tmp, &maps, list)
722 static int io_overlaps_block(struct pool *pool, struct bio *bio)
724 return bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT);
727 static int io_overwrites_block(struct pool *pool, struct bio *bio)
729 return (bio_data_dir(bio) == WRITE) &&
730 io_overlaps_block(pool, bio);
733 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
736 *save = bio->bi_end_io;
740 static int ensure_next_mapping(struct pool *pool)
742 if (pool->next_mapping)
745 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
747 return pool->next_mapping ? 0 : -ENOMEM;
750 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
752 struct dm_thin_new_mapping *r = pool->next_mapping;
754 BUG_ON(!pool->next_mapping);
756 pool->next_mapping = NULL;
761 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
762 struct dm_dev *origin, dm_block_t data_origin,
763 dm_block_t data_dest,
764 struct dm_bio_prison_cell *cell, struct bio *bio)
767 struct pool *pool = tc->pool;
768 struct dm_thin_new_mapping *m = get_next_mapping(pool);
770 INIT_LIST_HEAD(&m->list);
774 m->virt_block = virt_block;
775 m->data_block = data_dest;
780 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
784 * IO to pool_dev remaps to the pool target's data_dev.
786 * If the whole block of data is being overwritten, we can issue the
787 * bio immediately. Otherwise we use kcopyd to clone the data first.
789 if (io_overwrites_block(pool, bio)) {
790 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
792 h->overwrite_mapping = m;
794 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
795 inc_all_io_entry(pool, bio);
796 remap_and_issue(tc, bio, data_dest);
798 struct dm_io_region from, to;
800 from.bdev = origin->bdev;
801 from.sector = data_origin * pool->sectors_per_block;
802 from.count = pool->sectors_per_block;
804 to.bdev = tc->pool_dev->bdev;
805 to.sector = data_dest * pool->sectors_per_block;
806 to.count = pool->sectors_per_block;
808 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
809 0, copy_complete, m);
811 mempool_free(m, pool->mapping_pool);
812 DMERR_LIMIT("dm_kcopyd_copy() failed");
813 cell_error(pool, cell);
818 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
819 dm_block_t data_origin, dm_block_t data_dest,
820 struct dm_bio_prison_cell *cell, struct bio *bio)
822 schedule_copy(tc, virt_block, tc->pool_dev,
823 data_origin, data_dest, cell, bio);
826 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
827 dm_block_t data_dest,
828 struct dm_bio_prison_cell *cell, struct bio *bio)
830 schedule_copy(tc, virt_block, tc->origin_dev,
831 virt_block, data_dest, cell, bio);
834 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
835 dm_block_t data_block, struct dm_bio_prison_cell *cell,
838 struct pool *pool = tc->pool;
839 struct dm_thin_new_mapping *m = get_next_mapping(pool);
841 INIT_LIST_HEAD(&m->list);
845 m->virt_block = virt_block;
846 m->data_block = data_block;
852 * If the whole block of data is being overwritten or we are not
853 * zeroing pre-existing data, we can issue the bio immediately.
854 * Otherwise we use kcopyd to zero the data first.
856 if (!pool->pf.zero_new_blocks)
857 process_prepared_mapping(m);
859 else if (io_overwrites_block(pool, bio)) {
860 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
862 h->overwrite_mapping = m;
864 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
865 inc_all_io_entry(pool, bio);
866 remap_and_issue(tc, bio, data_block);
869 struct dm_io_region to;
871 to.bdev = tc->pool_dev->bdev;
872 to.sector = data_block * pool->sectors_per_block;
873 to.count = pool->sectors_per_block;
875 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
877 mempool_free(m, pool->mapping_pool);
878 DMERR_LIMIT("dm_kcopyd_zero() failed");
879 cell_error(pool, cell);
884 static int commit(struct pool *pool)
888 r = dm_pool_commit_metadata(pool->pmd);
890 DMERR_LIMIT("%s: commit failed: error = %d",
891 dm_device_name(pool->pool_md), r);
897 * A non-zero return indicates read_only or fail_io mode.
898 * Many callers don't care about the return value.
900 static int commit_or_fallback(struct pool *pool)
904 if (get_pool_mode(pool) != PM_WRITE)
909 set_pool_mode(pool, PM_READ_ONLY);
914 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
917 dm_block_t free_blocks;
919 struct pool *pool = tc->pool;
921 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
925 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
926 DMWARN("%s: reached low water mark for data device: sending event.",
927 dm_device_name(pool->pool_md));
928 spin_lock_irqsave(&pool->lock, flags);
929 pool->low_water_triggered = 1;
930 spin_unlock_irqrestore(&pool->lock, flags);
931 dm_table_event(pool->ti->table);
935 if (pool->no_free_space)
939 * Try to commit to see if that will free up some
942 (void) commit_or_fallback(pool);
944 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
949 * If we still have no space we set a flag to avoid
950 * doing all this checking and return -ENOSPC.
953 DMWARN("%s: no free space available.",
954 dm_device_name(pool->pool_md));
955 spin_lock_irqsave(&pool->lock, flags);
956 pool->no_free_space = 1;
957 spin_unlock_irqrestore(&pool->lock, flags);
963 r = dm_pool_alloc_data_block(pool->pmd, result);
971 * If we have run out of space, queue bios until the device is
972 * resumed, presumably after having been reloaded with more space.
974 static void retry_on_resume(struct bio *bio)
976 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
977 struct thin_c *tc = h->tc;
978 struct pool *pool = tc->pool;
981 spin_lock_irqsave(&pool->lock, flags);
982 bio_list_add(&pool->retry_on_resume_list, bio);
983 spin_unlock_irqrestore(&pool->lock, flags);
986 static void no_space(struct pool *pool, struct dm_bio_prison_cell *cell)
989 struct bio_list bios;
991 bio_list_init(&bios);
992 cell_release(pool, cell, &bios);
994 while ((bio = bio_list_pop(&bios)))
995 retry_on_resume(bio);
998 static void process_discard(struct thin_c *tc, struct bio *bio)
1001 unsigned long flags;
1002 struct pool *pool = tc->pool;
1003 struct dm_bio_prison_cell *cell, *cell2;
1004 struct dm_cell_key key, key2;
1005 dm_block_t block = get_bio_block(tc, bio);
1006 struct dm_thin_lookup_result lookup_result;
1007 struct dm_thin_new_mapping *m;
1009 build_virtual_key(tc->td, block, &key);
1010 if (bio_detain(tc->pool, &key, bio, &cell))
1013 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1017 * Check nobody is fiddling with this pool block. This can
1018 * happen if someone's in the process of breaking sharing
1021 build_data_key(tc->td, lookup_result.block, &key2);
1022 if (bio_detain(tc->pool, &key2, bio, &cell2)) {
1023 cell_defer_no_holder(tc, cell);
1027 if (io_overlaps_block(pool, bio)) {
1029 * IO may still be going to the destination block. We must
1030 * quiesce before we can do the removal.
1032 m = get_next_mapping(pool);
1034 m->pass_discard = (!lookup_result.shared) && pool->pf.discard_passdown;
1035 m->virt_block = block;
1036 m->data_block = lookup_result.block;
1042 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
1043 spin_lock_irqsave(&pool->lock, flags);
1044 list_add(&m->list, &pool->prepared_discards);
1045 spin_unlock_irqrestore(&pool->lock, flags);
1049 inc_all_io_entry(pool, bio);
1050 cell_defer_no_holder(tc, cell);
1051 cell_defer_no_holder(tc, cell2);
1054 * The DM core makes sure that the discard doesn't span
1055 * a block boundary. So we submit the discard of a
1056 * partial block appropriately.
1058 if ((!lookup_result.shared) && pool->pf.discard_passdown)
1059 remap_and_issue(tc, bio, lookup_result.block);
1067 * It isn't provisioned, just forget it.
1069 cell_defer_no_holder(tc, cell);
1074 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1076 cell_defer_no_holder(tc, cell);
1082 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1083 struct dm_cell_key *key,
1084 struct dm_thin_lookup_result *lookup_result,
1085 struct dm_bio_prison_cell *cell)
1088 dm_block_t data_block;
1089 struct pool *pool = tc->pool;
1091 r = alloc_data_block(tc, &data_block);
1094 schedule_internal_copy(tc, block, lookup_result->block,
1095 data_block, cell, bio);
1099 no_space(pool, cell);
1103 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1105 set_pool_mode(pool, PM_READ_ONLY);
1106 cell_error(pool, cell);
1111 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1113 struct dm_thin_lookup_result *lookup_result)
1115 struct dm_bio_prison_cell *cell;
1116 struct pool *pool = tc->pool;
1117 struct dm_cell_key key;
1120 * If cell is already occupied, then sharing is already in the process
1121 * of being broken so we have nothing further to do here.
1123 build_data_key(tc->td, lookup_result->block, &key);
1124 if (bio_detain(pool, &key, bio, &cell))
1127 if (bio_data_dir(bio) == WRITE && bio->bi_size)
1128 break_sharing(tc, bio, block, &key, lookup_result, cell);
1130 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1132 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1133 inc_all_io_entry(pool, bio);
1134 cell_defer_no_holder(tc, cell);
1136 remap_and_issue(tc, bio, lookup_result->block);
1140 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1141 struct dm_bio_prison_cell *cell)
1144 dm_block_t data_block;
1145 struct pool *pool = tc->pool;
1148 * Remap empty bios (flushes) immediately, without provisioning.
1150 if (!bio->bi_size) {
1151 inc_all_io_entry(pool, bio);
1152 cell_defer_no_holder(tc, cell);
1154 remap_and_issue(tc, bio, 0);
1159 * Fill read bios with zeroes and complete them immediately.
1161 if (bio_data_dir(bio) == READ) {
1163 cell_defer_no_holder(tc, cell);
1168 r = alloc_data_block(tc, &data_block);
1172 schedule_external_copy(tc, block, data_block, cell, bio);
1174 schedule_zero(tc, block, data_block, cell, bio);
1178 no_space(pool, cell);
1182 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1184 set_pool_mode(pool, PM_READ_ONLY);
1185 cell_error(pool, cell);
1190 static void process_bio(struct thin_c *tc, struct bio *bio)
1193 struct pool *pool = tc->pool;
1194 dm_block_t block = get_bio_block(tc, bio);
1195 struct dm_bio_prison_cell *cell;
1196 struct dm_cell_key key;
1197 struct dm_thin_lookup_result lookup_result;
1200 * If cell is already occupied, then the block is already
1201 * being provisioned so we have nothing further to do here.
1203 build_virtual_key(tc->td, block, &key);
1204 if (bio_detain(pool, &key, bio, &cell))
1207 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1210 if (lookup_result.shared) {
1211 process_shared_bio(tc, bio, block, &lookup_result);
1212 cell_defer_no_holder(tc, cell); /* FIXME: pass this cell into process_shared? */
1214 inc_all_io_entry(pool, bio);
1215 cell_defer_no_holder(tc, cell);
1217 remap_and_issue(tc, bio, lookup_result.block);
1222 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1223 inc_all_io_entry(pool, bio);
1224 cell_defer_no_holder(tc, cell);
1226 remap_to_origin_and_issue(tc, bio);
1228 provision_block(tc, bio, block, cell);
1232 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1234 cell_defer_no_holder(tc, cell);
1240 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1243 int rw = bio_data_dir(bio);
1244 dm_block_t block = get_bio_block(tc, bio);
1245 struct dm_thin_lookup_result lookup_result;
1247 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1250 if (lookup_result.shared && (rw == WRITE) && bio->bi_size)
1253 inc_all_io_entry(tc->pool, bio);
1254 remap_and_issue(tc, bio, lookup_result.block);
1264 if (tc->origin_dev) {
1265 inc_all_io_entry(tc->pool, bio);
1266 remap_to_origin_and_issue(tc, bio);
1275 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1282 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1288 * FIXME: should we also commit due to size of transaction, measured in
1291 static int need_commit_due_to_time(struct pool *pool)
1293 return jiffies < pool->last_commit_jiffies ||
1294 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1297 static void process_deferred_bios(struct pool *pool)
1299 unsigned long flags;
1301 struct bio_list bios;
1303 bio_list_init(&bios);
1305 spin_lock_irqsave(&pool->lock, flags);
1306 bio_list_merge(&bios, &pool->deferred_bios);
1307 bio_list_init(&pool->deferred_bios);
1308 spin_unlock_irqrestore(&pool->lock, flags);
1310 while ((bio = bio_list_pop(&bios))) {
1311 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1312 struct thin_c *tc = h->tc;
1315 * If we've got no free new_mapping structs, and processing
1316 * this bio might require one, we pause until there are some
1317 * prepared mappings to process.
1319 if (ensure_next_mapping(pool)) {
1320 spin_lock_irqsave(&pool->lock, flags);
1321 bio_list_merge(&pool->deferred_bios, &bios);
1322 spin_unlock_irqrestore(&pool->lock, flags);
1327 if (bio->bi_rw & REQ_DISCARD)
1328 pool->process_discard(tc, bio);
1330 pool->process_bio(tc, bio);
1334 * If there are any deferred flush bios, we must commit
1335 * the metadata before issuing them.
1337 bio_list_init(&bios);
1338 spin_lock_irqsave(&pool->lock, flags);
1339 bio_list_merge(&bios, &pool->deferred_flush_bios);
1340 bio_list_init(&pool->deferred_flush_bios);
1341 spin_unlock_irqrestore(&pool->lock, flags);
1343 if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))
1346 if (commit_or_fallback(pool)) {
1347 while ((bio = bio_list_pop(&bios)))
1351 pool->last_commit_jiffies = jiffies;
1353 while ((bio = bio_list_pop(&bios)))
1354 generic_make_request(bio);
1357 static void do_worker(struct work_struct *ws)
1359 struct pool *pool = container_of(ws, struct pool, worker);
1361 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1362 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1363 process_deferred_bios(pool);
1367 * We want to commit periodically so that not too much
1368 * unwritten data builds up.
1370 static void do_waker(struct work_struct *ws)
1372 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1374 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1377 /*----------------------------------------------------------------*/
1379 static enum pool_mode get_pool_mode(struct pool *pool)
1381 return pool->pf.mode;
1384 static void set_pool_mode(struct pool *pool, enum pool_mode mode)
1388 pool->pf.mode = mode;
1392 DMERR("%s: switching pool to failure mode",
1393 dm_device_name(pool->pool_md));
1394 pool->process_bio = process_bio_fail;
1395 pool->process_discard = process_bio_fail;
1396 pool->process_prepared_mapping = process_prepared_mapping_fail;
1397 pool->process_prepared_discard = process_prepared_discard_fail;
1401 DMERR("%s: switching pool to read-only mode",
1402 dm_device_name(pool->pool_md));
1403 r = dm_pool_abort_metadata(pool->pmd);
1405 DMERR("%s: aborting transaction failed",
1406 dm_device_name(pool->pool_md));
1407 set_pool_mode(pool, PM_FAIL);
1409 dm_pool_metadata_read_only(pool->pmd);
1410 pool->process_bio = process_bio_read_only;
1411 pool->process_discard = process_discard;
1412 pool->process_prepared_mapping = process_prepared_mapping_fail;
1413 pool->process_prepared_discard = process_prepared_discard_passdown;
1418 pool->process_bio = process_bio;
1419 pool->process_discard = process_discard;
1420 pool->process_prepared_mapping = process_prepared_mapping;
1421 pool->process_prepared_discard = process_prepared_discard;
1426 /*----------------------------------------------------------------*/
1429 * Mapping functions.
1433 * Called only while mapping a thin bio to hand it over to the workqueue.
1435 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1437 unsigned long flags;
1438 struct pool *pool = tc->pool;
1440 spin_lock_irqsave(&pool->lock, flags);
1441 bio_list_add(&pool->deferred_bios, bio);
1442 spin_unlock_irqrestore(&pool->lock, flags);
1447 static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
1449 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1452 h->shared_read_entry = NULL;
1453 h->all_io_entry = NULL;
1454 h->overwrite_mapping = NULL;
1458 * Non-blocking function called from the thin target's map function.
1460 static int thin_bio_map(struct dm_target *ti, struct bio *bio)
1463 struct thin_c *tc = ti->private;
1464 dm_block_t block = get_bio_block(tc, bio);
1465 struct dm_thin_device *td = tc->td;
1466 struct dm_thin_lookup_result result;
1467 struct dm_bio_prison_cell cell1, cell2;
1468 struct dm_bio_prison_cell *cell_result;
1469 struct dm_cell_key key;
1471 thin_hook_bio(tc, bio);
1473 if (get_pool_mode(tc->pool) == PM_FAIL) {
1475 return DM_MAPIO_SUBMITTED;
1478 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
1479 thin_defer_bio(tc, bio);
1480 return DM_MAPIO_SUBMITTED;
1483 r = dm_thin_find_block(td, block, 0, &result);
1486 * Note that we defer readahead too.
1490 if (unlikely(result.shared)) {
1492 * We have a race condition here between the
1493 * result.shared value returned by the lookup and
1494 * snapshot creation, which may cause new
1497 * To avoid this always quiesce the origin before
1498 * taking the snap. You want to do this anyway to
1499 * ensure a consistent application view
1502 * More distant ancestors are irrelevant. The
1503 * shared flag will be set in their case.
1505 thin_defer_bio(tc, bio);
1506 return DM_MAPIO_SUBMITTED;
1509 build_virtual_key(tc->td, block, &key);
1510 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
1511 return DM_MAPIO_SUBMITTED;
1513 build_data_key(tc->td, result.block, &key);
1514 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
1515 cell_defer_no_holder_no_free(tc, &cell1);
1516 return DM_MAPIO_SUBMITTED;
1519 inc_all_io_entry(tc->pool, bio);
1520 cell_defer_no_holder_no_free(tc, &cell2);
1521 cell_defer_no_holder_no_free(tc, &cell1);
1523 remap(tc, bio, result.block);
1524 return DM_MAPIO_REMAPPED;
1527 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
1529 * This block isn't provisioned, and we have no way
1530 * of doing so. Just error it.
1533 return DM_MAPIO_SUBMITTED;
1539 * In future, the failed dm_thin_find_block above could
1540 * provide the hint to load the metadata into cache.
1542 thin_defer_bio(tc, bio);
1543 return DM_MAPIO_SUBMITTED;
1547 * Must always call bio_io_error on failure.
1548 * dm_thin_find_block can fail with -EINVAL if the
1549 * pool is switched to fail-io mode.
1552 return DM_MAPIO_SUBMITTED;
1556 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1559 unsigned long flags;
1560 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1562 spin_lock_irqsave(&pt->pool->lock, flags);
1563 r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1564 spin_unlock_irqrestore(&pt->pool->lock, flags);
1567 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1568 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1574 static void __requeue_bios(struct pool *pool)
1576 bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1577 bio_list_init(&pool->retry_on_resume_list);
1580 /*----------------------------------------------------------------
1581 * Binding of control targets to a pool object
1582 *--------------------------------------------------------------*/
1583 static bool data_dev_supports_discard(struct pool_c *pt)
1585 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1587 return q && blk_queue_discard(q);
1590 static bool is_factor(sector_t block_size, uint32_t n)
1592 return !sector_div(block_size, n);
1596 * If discard_passdown was enabled verify that the data device
1597 * supports discards. Disable discard_passdown if not.
1599 static void disable_passdown_if_not_supported(struct pool_c *pt)
1601 struct pool *pool = pt->pool;
1602 struct block_device *data_bdev = pt->data_dev->bdev;
1603 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
1604 sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
1605 const char *reason = NULL;
1606 char buf[BDEVNAME_SIZE];
1608 if (!pt->adjusted_pf.discard_passdown)
1611 if (!data_dev_supports_discard(pt))
1612 reason = "discard unsupported";
1614 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
1615 reason = "max discard sectors smaller than a block";
1617 else if (data_limits->discard_granularity > block_size)
1618 reason = "discard granularity larger than a block";
1620 else if (!is_factor(block_size, data_limits->discard_granularity))
1621 reason = "discard granularity not a factor of block size";
1624 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
1625 pt->adjusted_pf.discard_passdown = false;
1629 static int bind_control_target(struct pool *pool, struct dm_target *ti)
1631 struct pool_c *pt = ti->private;
1634 * We want to make sure that degraded pools are never upgraded.
1636 enum pool_mode old_mode = pool->pf.mode;
1637 enum pool_mode new_mode = pt->adjusted_pf.mode;
1639 if (old_mode > new_mode)
1640 new_mode = old_mode;
1643 pool->low_water_blocks = pt->low_water_blocks;
1644 pool->pf = pt->adjusted_pf;
1646 set_pool_mode(pool, new_mode);
1651 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1657 /*----------------------------------------------------------------
1659 *--------------------------------------------------------------*/
1660 /* Initialize pool features. */
1661 static void pool_features_init(struct pool_features *pf)
1663 pf->mode = PM_WRITE;
1664 pf->zero_new_blocks = true;
1665 pf->discard_enabled = true;
1666 pf->discard_passdown = true;
1669 static void __pool_destroy(struct pool *pool)
1671 __pool_table_remove(pool);
1673 if (dm_pool_metadata_close(pool->pmd) < 0)
1674 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1676 dm_bio_prison_destroy(pool->prison);
1677 dm_kcopyd_client_destroy(pool->copier);
1680 destroy_workqueue(pool->wq);
1682 if (pool->next_mapping)
1683 mempool_free(pool->next_mapping, pool->mapping_pool);
1684 mempool_destroy(pool->mapping_pool);
1685 dm_deferred_set_destroy(pool->shared_read_ds);
1686 dm_deferred_set_destroy(pool->all_io_ds);
1690 static struct kmem_cache *_new_mapping_cache;
1692 static struct pool *pool_create(struct mapped_device *pool_md,
1693 struct block_device *metadata_dev,
1694 unsigned long block_size,
1695 int read_only, char **error)
1700 struct dm_pool_metadata *pmd;
1701 bool format_device = read_only ? false : true;
1703 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
1705 *error = "Error creating metadata object";
1706 return (struct pool *)pmd;
1709 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1711 *error = "Error allocating memory for pool";
1712 err_p = ERR_PTR(-ENOMEM);
1717 pool->sectors_per_block = block_size;
1718 if (block_size & (block_size - 1))
1719 pool->sectors_per_block_shift = -1;
1721 pool->sectors_per_block_shift = __ffs(block_size);
1722 pool->low_water_blocks = 0;
1723 pool_features_init(&pool->pf);
1724 pool->prison = dm_bio_prison_create(PRISON_CELLS);
1725 if (!pool->prison) {
1726 *error = "Error creating pool's bio prison";
1727 err_p = ERR_PTR(-ENOMEM);
1731 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1732 if (IS_ERR(pool->copier)) {
1733 r = PTR_ERR(pool->copier);
1734 *error = "Error creating pool's kcopyd client";
1736 goto bad_kcopyd_client;
1740 * Create singlethreaded workqueue that will service all devices
1741 * that use this metadata.
1743 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1745 *error = "Error creating pool's workqueue";
1746 err_p = ERR_PTR(-ENOMEM);
1750 INIT_WORK(&pool->worker, do_worker);
1751 INIT_DELAYED_WORK(&pool->waker, do_waker);
1752 spin_lock_init(&pool->lock);
1753 bio_list_init(&pool->deferred_bios);
1754 bio_list_init(&pool->deferred_flush_bios);
1755 INIT_LIST_HEAD(&pool->prepared_mappings);
1756 INIT_LIST_HEAD(&pool->prepared_discards);
1757 pool->low_water_triggered = 0;
1758 pool->no_free_space = 0;
1759 bio_list_init(&pool->retry_on_resume_list);
1761 pool->shared_read_ds = dm_deferred_set_create();
1762 if (!pool->shared_read_ds) {
1763 *error = "Error creating pool's shared read deferred set";
1764 err_p = ERR_PTR(-ENOMEM);
1765 goto bad_shared_read_ds;
1768 pool->all_io_ds = dm_deferred_set_create();
1769 if (!pool->all_io_ds) {
1770 *error = "Error creating pool's all io deferred set";
1771 err_p = ERR_PTR(-ENOMEM);
1775 pool->next_mapping = NULL;
1776 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
1777 _new_mapping_cache);
1778 if (!pool->mapping_pool) {
1779 *error = "Error creating pool's mapping mempool";
1780 err_p = ERR_PTR(-ENOMEM);
1781 goto bad_mapping_pool;
1784 pool->ref_count = 1;
1785 pool->last_commit_jiffies = jiffies;
1786 pool->pool_md = pool_md;
1787 pool->md_dev = metadata_dev;
1788 __pool_table_insert(pool);
1793 dm_deferred_set_destroy(pool->all_io_ds);
1795 dm_deferred_set_destroy(pool->shared_read_ds);
1797 destroy_workqueue(pool->wq);
1799 dm_kcopyd_client_destroy(pool->copier);
1801 dm_bio_prison_destroy(pool->prison);
1805 if (dm_pool_metadata_close(pmd))
1806 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1811 static void __pool_inc(struct pool *pool)
1813 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1817 static void __pool_dec(struct pool *pool)
1819 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1820 BUG_ON(!pool->ref_count);
1821 if (!--pool->ref_count)
1822 __pool_destroy(pool);
1825 static struct pool *__pool_find(struct mapped_device *pool_md,
1826 struct block_device *metadata_dev,
1827 unsigned long block_size, int read_only,
1828 char **error, int *created)
1830 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1833 if (pool->pool_md != pool_md) {
1834 *error = "metadata device already in use by a pool";
1835 return ERR_PTR(-EBUSY);
1840 pool = __pool_table_lookup(pool_md);
1842 if (pool->md_dev != metadata_dev) {
1843 *error = "different pool cannot replace a pool";
1844 return ERR_PTR(-EINVAL);
1849 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
1857 /*----------------------------------------------------------------
1858 * Pool target methods
1859 *--------------------------------------------------------------*/
1860 static void pool_dtr(struct dm_target *ti)
1862 struct pool_c *pt = ti->private;
1864 mutex_lock(&dm_thin_pool_table.mutex);
1866 unbind_control_target(pt->pool, ti);
1867 __pool_dec(pt->pool);
1868 dm_put_device(ti, pt->metadata_dev);
1869 dm_put_device(ti, pt->data_dev);
1872 mutex_unlock(&dm_thin_pool_table.mutex);
1875 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
1876 struct dm_target *ti)
1880 const char *arg_name;
1882 static struct dm_arg _args[] = {
1883 {0, 3, "Invalid number of pool feature arguments"},
1887 * No feature arguments supplied.
1892 r = dm_read_arg_group(_args, as, &argc, &ti->error);
1896 while (argc && !r) {
1897 arg_name = dm_shift_arg(as);
1900 if (!strcasecmp(arg_name, "skip_block_zeroing"))
1901 pf->zero_new_blocks = false;
1903 else if (!strcasecmp(arg_name, "ignore_discard"))
1904 pf->discard_enabled = false;
1906 else if (!strcasecmp(arg_name, "no_discard_passdown"))
1907 pf->discard_passdown = false;
1909 else if (!strcasecmp(arg_name, "read_only"))
1910 pf->mode = PM_READ_ONLY;
1913 ti->error = "Unrecognised pool feature requested";
1922 static void metadata_low_callback(void *context)
1924 struct pool *pool = context;
1926 DMWARN("%s: reached low water mark for metadata device: sending event.",
1927 dm_device_name(pool->pool_md));
1929 dm_table_event(pool->ti->table);
1932 static sector_t get_metadata_dev_size(struct block_device *bdev)
1934 sector_t metadata_dev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
1935 char buffer[BDEVNAME_SIZE];
1937 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) {
1938 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1939 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
1940 metadata_dev_size = THIN_METADATA_MAX_SECTORS_WARNING;
1943 return metadata_dev_size;
1946 static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
1948 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
1950 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
1952 return metadata_dev_size;
1956 * When a metadata threshold is crossed a dm event is triggered, and
1957 * userland should respond by growing the metadata device. We could let
1958 * userland set the threshold, like we do with the data threshold, but I'm
1959 * not sure they know enough to do this well.
1961 static dm_block_t calc_metadata_threshold(struct pool_c *pt)
1964 * 4M is ample for all ops with the possible exception of thin
1965 * device deletion which is harmless if it fails (just retry the
1966 * delete after you've grown the device).
1968 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
1969 return min((dm_block_t)1024ULL /* 4M */, quarter);
1973 * thin-pool <metadata dev> <data dev>
1974 * <data block size (sectors)>
1975 * <low water mark (blocks)>
1976 * [<#feature args> [<arg>]*]
1978 * Optional feature arguments are:
1979 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1980 * ignore_discard: disable discard
1981 * no_discard_passdown: don't pass discards down to the data device
1983 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
1985 int r, pool_created = 0;
1988 struct pool_features pf;
1989 struct dm_arg_set as;
1990 struct dm_dev *data_dev;
1991 unsigned long block_size;
1992 dm_block_t low_water_blocks;
1993 struct dm_dev *metadata_dev;
1994 fmode_t metadata_mode;
1997 * FIXME Remove validation from scope of lock.
1999 mutex_lock(&dm_thin_pool_table.mutex);
2002 ti->error = "Invalid argument count";
2011 * Set default pool features.
2013 pool_features_init(&pf);
2015 dm_consume_args(&as, 4);
2016 r = parse_pool_features(&as, &pf, ti);
2020 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
2021 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
2023 ti->error = "Error opening metadata block device";
2028 * Run for the side-effect of possibly issuing a warning if the
2029 * device is too big.
2031 (void) get_metadata_dev_size(metadata_dev->bdev);
2033 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
2035 ti->error = "Error getting data device";
2039 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
2040 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
2041 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
2042 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
2043 ti->error = "Invalid block size";
2048 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
2049 ti->error = "Invalid low water mark";
2054 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
2060 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
2061 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
2068 * 'pool_created' reflects whether this is the first table load.
2069 * Top level discard support is not allowed to be changed after
2070 * initial load. This would require a pool reload to trigger thin
2073 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
2074 ti->error = "Discard support cannot be disabled once enabled";
2076 goto out_flags_changed;
2081 pt->metadata_dev = metadata_dev;
2082 pt->data_dev = data_dev;
2083 pt->low_water_blocks = low_water_blocks;
2084 pt->adjusted_pf = pt->requested_pf = pf;
2085 ti->num_flush_bios = 1;
2088 * Only need to enable discards if the pool should pass
2089 * them down to the data device. The thin device's discard
2090 * processing will cause mappings to be removed from the btree.
2092 if (pf.discard_enabled && pf.discard_passdown) {
2093 ti->num_discard_bios = 1;
2096 * Setting 'discards_supported' circumvents the normal
2097 * stacking of discard limits (this keeps the pool and
2098 * thin devices' discard limits consistent).
2100 ti->discards_supported = true;
2101 ti->discard_zeroes_data_unsupported = true;
2105 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
2106 calc_metadata_threshold(pt),
2107 metadata_low_callback,
2112 pt->callbacks.congested_fn = pool_is_congested;
2113 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2115 mutex_unlock(&dm_thin_pool_table.mutex);
2124 dm_put_device(ti, data_dev);
2126 dm_put_device(ti, metadata_dev);
2128 mutex_unlock(&dm_thin_pool_table.mutex);
2133 static int pool_map(struct dm_target *ti, struct bio *bio)
2136 struct pool_c *pt = ti->private;
2137 struct pool *pool = pt->pool;
2138 unsigned long flags;
2141 * As this is a singleton target, ti->begin is always zero.
2143 spin_lock_irqsave(&pool->lock, flags);
2144 bio->bi_bdev = pt->data_dev->bdev;
2145 r = DM_MAPIO_REMAPPED;
2146 spin_unlock_irqrestore(&pool->lock, flags);
2151 static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
2154 struct pool_c *pt = ti->private;
2155 struct pool *pool = pt->pool;
2156 sector_t data_size = ti->len;
2157 dm_block_t sb_data_size;
2159 *need_commit = false;
2161 (void) sector_div(data_size, pool->sectors_per_block);
2163 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2165 DMERR("%s: failed to retrieve data device size",
2166 dm_device_name(pool->pool_md));
2170 if (data_size < sb_data_size) {
2171 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
2172 dm_device_name(pool->pool_md),
2173 (unsigned long long)data_size, sb_data_size);
2176 } else if (data_size > sb_data_size) {
2177 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2179 DMERR("%s: failed to resize data device",
2180 dm_device_name(pool->pool_md));
2181 set_pool_mode(pool, PM_READ_ONLY);
2185 *need_commit = true;
2191 static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
2194 struct pool_c *pt = ti->private;
2195 struct pool *pool = pt->pool;
2196 dm_block_t metadata_dev_size, sb_metadata_dev_size;
2198 *need_commit = false;
2200 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
2202 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
2204 DMERR("%s: failed to retrieve metadata device size",
2205 dm_device_name(pool->pool_md));
2209 if (metadata_dev_size < sb_metadata_dev_size) {
2210 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
2211 dm_device_name(pool->pool_md),
2212 metadata_dev_size, sb_metadata_dev_size);
2215 } else if (metadata_dev_size > sb_metadata_dev_size) {
2216 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
2218 DMERR("%s: failed to resize metadata device",
2219 dm_device_name(pool->pool_md));
2223 *need_commit = true;
2230 * Retrieves the number of blocks of the data device from
2231 * the superblock and compares it to the actual device size,
2232 * thus resizing the data device in case it has grown.
2234 * This both copes with opening preallocated data devices in the ctr
2235 * being followed by a resume
2237 * calling the resume method individually after userspace has
2238 * grown the data device in reaction to a table event.
2240 static int pool_preresume(struct dm_target *ti)
2243 bool need_commit1, need_commit2;
2244 struct pool_c *pt = ti->private;
2245 struct pool *pool = pt->pool;
2248 * Take control of the pool object.
2250 r = bind_control_target(pool, ti);
2254 r = maybe_resize_data_dev(ti, &need_commit1);
2258 r = maybe_resize_metadata_dev(ti, &need_commit2);
2262 if (need_commit1 || need_commit2)
2263 (void) commit_or_fallback(pool);
2268 static void pool_resume(struct dm_target *ti)
2270 struct pool_c *pt = ti->private;
2271 struct pool *pool = pt->pool;
2272 unsigned long flags;
2274 spin_lock_irqsave(&pool->lock, flags);
2275 pool->low_water_triggered = 0;
2276 pool->no_free_space = 0;
2277 __requeue_bios(pool);
2278 spin_unlock_irqrestore(&pool->lock, flags);
2280 do_waker(&pool->waker.work);
2283 static void pool_postsuspend(struct dm_target *ti)
2285 struct pool_c *pt = ti->private;
2286 struct pool *pool = pt->pool;
2288 cancel_delayed_work(&pool->waker);
2289 flush_workqueue(pool->wq);
2290 (void) commit_or_fallback(pool);
2293 static int check_arg_count(unsigned argc, unsigned args_required)
2295 if (argc != args_required) {
2296 DMWARN("Message received with %u arguments instead of %u.",
2297 argc, args_required);
2304 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2306 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2307 *dev_id <= MAX_DEV_ID)
2311 DMWARN("Message received with invalid device id: %s", arg);
2316 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2321 r = check_arg_count(argc, 2);
2325 r = read_dev_id(argv[1], &dev_id, 1);
2329 r = dm_pool_create_thin(pool->pmd, dev_id);
2331 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2339 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2342 dm_thin_id origin_dev_id;
2345 r = check_arg_count(argc, 3);
2349 r = read_dev_id(argv[1], &dev_id, 1);
2353 r = read_dev_id(argv[2], &origin_dev_id, 1);
2357 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2359 DMWARN("Creation of new snapshot %s of device %s failed.",
2367 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2372 r = check_arg_count(argc, 2);
2376 r = read_dev_id(argv[1], &dev_id, 1);
2380 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2382 DMWARN("Deletion of thin device %s failed.", argv[1]);
2387 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2389 dm_thin_id old_id, new_id;
2392 r = check_arg_count(argc, 3);
2396 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2397 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2401 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2402 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2406 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2408 DMWARN("Failed to change transaction id from %s to %s.",
2416 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2420 r = check_arg_count(argc, 1);
2424 (void) commit_or_fallback(pool);
2426 r = dm_pool_reserve_metadata_snap(pool->pmd);
2428 DMWARN("reserve_metadata_snap message failed.");
2433 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2437 r = check_arg_count(argc, 1);
2441 r = dm_pool_release_metadata_snap(pool->pmd);
2443 DMWARN("release_metadata_snap message failed.");
2449 * Messages supported:
2450 * create_thin <dev_id>
2451 * create_snap <dev_id> <origin_id>
2453 * trim <dev_id> <new_size_in_sectors>
2454 * set_transaction_id <current_trans_id> <new_trans_id>
2455 * reserve_metadata_snap
2456 * release_metadata_snap
2458 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2461 struct pool_c *pt = ti->private;
2462 struct pool *pool = pt->pool;
2464 if (!strcasecmp(argv[0], "create_thin"))
2465 r = process_create_thin_mesg(argc, argv, pool);
2467 else if (!strcasecmp(argv[0], "create_snap"))
2468 r = process_create_snap_mesg(argc, argv, pool);
2470 else if (!strcasecmp(argv[0], "delete"))
2471 r = process_delete_mesg(argc, argv, pool);
2473 else if (!strcasecmp(argv[0], "set_transaction_id"))
2474 r = process_set_transaction_id_mesg(argc, argv, pool);
2476 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
2477 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
2479 else if (!strcasecmp(argv[0], "release_metadata_snap"))
2480 r = process_release_metadata_snap_mesg(argc, argv, pool);
2483 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2486 (void) commit_or_fallback(pool);
2491 static void emit_flags(struct pool_features *pf, char *result,
2492 unsigned sz, unsigned maxlen)
2494 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
2495 !pf->discard_passdown + (pf->mode == PM_READ_ONLY);
2496 DMEMIT("%u ", count);
2498 if (!pf->zero_new_blocks)
2499 DMEMIT("skip_block_zeroing ");
2501 if (!pf->discard_enabled)
2502 DMEMIT("ignore_discard ");
2504 if (!pf->discard_passdown)
2505 DMEMIT("no_discard_passdown ");
2507 if (pf->mode == PM_READ_ONLY)
2508 DMEMIT("read_only ");
2513 * <transaction id> <used metadata sectors>/<total metadata sectors>
2514 * <used data sectors>/<total data sectors> <held metadata root>
2516 static void pool_status(struct dm_target *ti, status_type_t type,
2517 unsigned status_flags, char *result, unsigned maxlen)
2521 uint64_t transaction_id;
2522 dm_block_t nr_free_blocks_data;
2523 dm_block_t nr_free_blocks_metadata;
2524 dm_block_t nr_blocks_data;
2525 dm_block_t nr_blocks_metadata;
2526 dm_block_t held_root;
2527 char buf[BDEVNAME_SIZE];
2528 char buf2[BDEVNAME_SIZE];
2529 struct pool_c *pt = ti->private;
2530 struct pool *pool = pt->pool;
2533 case STATUSTYPE_INFO:
2534 if (get_pool_mode(pool) == PM_FAIL) {
2539 /* Commit to ensure statistics aren't out-of-date */
2540 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
2541 (void) commit_or_fallback(pool);
2543 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
2545 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
2546 dm_device_name(pool->pool_md), r);
2550 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
2552 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
2553 dm_device_name(pool->pool_md), r);
2557 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2559 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
2560 dm_device_name(pool->pool_md), r);
2564 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
2566 DMERR("%s: dm_pool_get_free_block_count returned %d",
2567 dm_device_name(pool->pool_md), r);
2571 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2573 DMERR("%s: dm_pool_get_data_dev_size returned %d",
2574 dm_device_name(pool->pool_md), r);
2578 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
2580 DMERR("%s: dm_pool_get_metadata_snap returned %d",
2581 dm_device_name(pool->pool_md), r);
2585 DMEMIT("%llu %llu/%llu %llu/%llu ",
2586 (unsigned long long)transaction_id,
2587 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2588 (unsigned long long)nr_blocks_metadata,
2589 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2590 (unsigned long long)nr_blocks_data);
2593 DMEMIT("%llu ", held_root);
2597 if (pool->pf.mode == PM_READ_ONLY)
2602 if (!pool->pf.discard_enabled)
2603 DMEMIT("ignore_discard");
2604 else if (pool->pf.discard_passdown)
2605 DMEMIT("discard_passdown");
2607 DMEMIT("no_discard_passdown");
2611 case STATUSTYPE_TABLE:
2612 DMEMIT("%s %s %lu %llu ",
2613 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2614 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2615 (unsigned long)pool->sectors_per_block,
2616 (unsigned long long)pt->low_water_blocks);
2617 emit_flags(&pt->requested_pf, result, sz, maxlen);
2626 static int pool_iterate_devices(struct dm_target *ti,
2627 iterate_devices_callout_fn fn, void *data)
2629 struct pool_c *pt = ti->private;
2631 return fn(ti, pt->data_dev, 0, ti->len, data);
2634 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2635 struct bio_vec *biovec, int max_size)
2637 struct pool_c *pt = ti->private;
2638 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2640 if (!q->merge_bvec_fn)
2643 bvm->bi_bdev = pt->data_dev->bdev;
2645 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2648 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
2650 struct pool *pool = pt->pool;
2651 struct queue_limits *data_limits;
2653 limits->max_discard_sectors = pool->sectors_per_block;
2656 * discard_granularity is just a hint, and not enforced.
2658 if (pt->adjusted_pf.discard_passdown) {
2659 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
2660 limits->discard_granularity = data_limits->discard_granularity;
2662 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
2665 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2667 struct pool_c *pt = ti->private;
2668 struct pool *pool = pt->pool;
2669 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
2672 * If the system-determined stacked limits are compatible with the
2673 * pool's blocksize (io_opt is a factor) do not override them.
2675 if (io_opt_sectors < pool->sectors_per_block ||
2676 do_div(io_opt_sectors, pool->sectors_per_block)) {
2677 blk_limits_io_min(limits, 0);
2678 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2682 * pt->adjusted_pf is a staging area for the actual features to use.
2683 * They get transferred to the live pool in bind_control_target()
2684 * called from pool_preresume().
2686 if (!pt->adjusted_pf.discard_enabled)
2689 disable_passdown_if_not_supported(pt);
2691 set_discard_limits(pt, limits);
2694 static struct target_type pool_target = {
2695 .name = "thin-pool",
2696 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2697 DM_TARGET_IMMUTABLE,
2698 .version = {1, 8, 0},
2699 .module = THIS_MODULE,
2703 .postsuspend = pool_postsuspend,
2704 .preresume = pool_preresume,
2705 .resume = pool_resume,
2706 .message = pool_message,
2707 .status = pool_status,
2708 .merge = pool_merge,
2709 .iterate_devices = pool_iterate_devices,
2710 .io_hints = pool_io_hints,
2713 /*----------------------------------------------------------------
2714 * Thin target methods
2715 *--------------------------------------------------------------*/
2716 static void thin_dtr(struct dm_target *ti)
2718 struct thin_c *tc = ti->private;
2720 mutex_lock(&dm_thin_pool_table.mutex);
2722 __pool_dec(tc->pool);
2723 dm_pool_close_thin_device(tc->td);
2724 dm_put_device(ti, tc->pool_dev);
2726 dm_put_device(ti, tc->origin_dev);
2729 mutex_unlock(&dm_thin_pool_table.mutex);
2733 * Thin target parameters:
2735 * <pool_dev> <dev_id> [origin_dev]
2737 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2738 * dev_id: the internal device identifier
2739 * origin_dev: a device external to the pool that should act as the origin
2741 * If the pool device has discards disabled, they get disabled for the thin
2744 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2748 struct dm_dev *pool_dev, *origin_dev;
2749 struct mapped_device *pool_md;
2751 mutex_lock(&dm_thin_pool_table.mutex);
2753 if (argc != 2 && argc != 3) {
2754 ti->error = "Invalid argument count";
2759 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2761 ti->error = "Out of memory";
2767 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
2769 ti->error = "Error opening origin device";
2770 goto bad_origin_dev;
2772 tc->origin_dev = origin_dev;
2775 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2777 ti->error = "Error opening pool device";
2780 tc->pool_dev = pool_dev;
2782 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2783 ti->error = "Invalid device id";
2788 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2790 ti->error = "Couldn't get pool mapped device";
2795 tc->pool = __pool_table_lookup(pool_md);
2797 ti->error = "Couldn't find pool object";
2799 goto bad_pool_lookup;
2801 __pool_inc(tc->pool);
2803 if (get_pool_mode(tc->pool) == PM_FAIL) {
2804 ti->error = "Couldn't open thin device, Pool is in fail mode";
2808 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
2810 ti->error = "Couldn't open thin internal device";
2814 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
2818 ti->num_flush_bios = 1;
2819 ti->flush_supported = true;
2820 ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
2822 /* In case the pool supports discards, pass them on. */
2823 if (tc->pool->pf.discard_enabled) {
2824 ti->discards_supported = true;
2825 ti->num_discard_bios = 1;
2826 ti->discard_zeroes_data_unsupported = true;
2827 /* Discard bios must be split on a block boundary */
2828 ti->split_discard_bios = true;
2833 mutex_unlock(&dm_thin_pool_table.mutex);
2838 __pool_dec(tc->pool);
2842 dm_put_device(ti, tc->pool_dev);
2845 dm_put_device(ti, tc->origin_dev);
2849 mutex_unlock(&dm_thin_pool_table.mutex);
2854 static int thin_map(struct dm_target *ti, struct bio *bio)
2856 bio->bi_sector = dm_target_offset(ti, bio->bi_sector);
2858 return thin_bio_map(ti, bio);
2861 static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
2863 unsigned long flags;
2864 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2865 struct list_head work;
2866 struct dm_thin_new_mapping *m, *tmp;
2867 struct pool *pool = h->tc->pool;
2869 if (h->shared_read_entry) {
2870 INIT_LIST_HEAD(&work);
2871 dm_deferred_entry_dec(h->shared_read_entry, &work);
2873 spin_lock_irqsave(&pool->lock, flags);
2874 list_for_each_entry_safe(m, tmp, &work, list) {
2877 __maybe_add_mapping(m);
2879 spin_unlock_irqrestore(&pool->lock, flags);
2882 if (h->all_io_entry) {
2883 INIT_LIST_HEAD(&work);
2884 dm_deferred_entry_dec(h->all_io_entry, &work);
2885 if (!list_empty(&work)) {
2886 spin_lock_irqsave(&pool->lock, flags);
2887 list_for_each_entry_safe(m, tmp, &work, list)
2888 list_add(&m->list, &pool->prepared_discards);
2889 spin_unlock_irqrestore(&pool->lock, flags);
2897 static void thin_postsuspend(struct dm_target *ti)
2899 if (dm_noflush_suspending(ti))
2900 requeue_io((struct thin_c *)ti->private);
2904 * <nr mapped sectors> <highest mapped sector>
2906 static void thin_status(struct dm_target *ti, status_type_t type,
2907 unsigned status_flags, char *result, unsigned maxlen)
2911 dm_block_t mapped, highest;
2912 char buf[BDEVNAME_SIZE];
2913 struct thin_c *tc = ti->private;
2915 if (get_pool_mode(tc->pool) == PM_FAIL) {
2924 case STATUSTYPE_INFO:
2925 r = dm_thin_get_mapped_count(tc->td, &mapped);
2927 DMERR("dm_thin_get_mapped_count returned %d", r);
2931 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
2933 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
2937 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
2939 DMEMIT("%llu", ((highest + 1) *
2940 tc->pool->sectors_per_block) - 1);
2945 case STATUSTYPE_TABLE:
2947 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
2948 (unsigned long) tc->dev_id);
2950 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
2961 static int thin_iterate_devices(struct dm_target *ti,
2962 iterate_devices_callout_fn fn, void *data)
2965 struct thin_c *tc = ti->private;
2966 struct pool *pool = tc->pool;
2969 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2970 * we follow a more convoluted path through to the pool's target.
2973 return 0; /* nothing is bound */
2975 blocks = pool->ti->len;
2976 (void) sector_div(blocks, pool->sectors_per_block);
2978 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
2983 static struct target_type thin_target = {
2985 .version = {1, 8, 0},
2986 .module = THIS_MODULE,
2990 .end_io = thin_endio,
2991 .postsuspend = thin_postsuspend,
2992 .status = thin_status,
2993 .iterate_devices = thin_iterate_devices,
2996 /*----------------------------------------------------------------*/
2998 static int __init dm_thin_init(void)
3004 r = dm_register_target(&thin_target);
3008 r = dm_register_target(&pool_target);
3010 goto bad_pool_target;
3014 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
3015 if (!_new_mapping_cache)
3016 goto bad_new_mapping_cache;
3020 bad_new_mapping_cache:
3021 dm_unregister_target(&pool_target);
3023 dm_unregister_target(&thin_target);
3028 static void dm_thin_exit(void)
3030 dm_unregister_target(&thin_target);
3031 dm_unregister_target(&pool_target);
3033 kmem_cache_destroy(_new_mapping_cache);
3036 module_init(dm_thin_init);
3037 module_exit(dm_thin_exit);
3039 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
3040 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3041 MODULE_LICENSE("GPL");