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
30 * The block size of the device holding pool data must be
31 * between 64KB and 1GB.
33 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
34 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
37 * Device id is restricted to 24 bits.
39 #define MAX_DEV_ID ((1 << 24) - 1)
42 * How do we handle breaking sharing of data blocks?
43 * =================================================
45 * We use a standard copy-on-write btree to store the mappings for the
46 * devices (note I'm talking about copy-on-write of the metadata here, not
47 * the data). When you take an internal snapshot you clone the root node
48 * of the origin btree. After this there is no concept of an origin or a
49 * snapshot. They are just two device trees that happen to point to the
52 * When we get a write in we decide if it's to a shared data block using
53 * some timestamp magic. If it is, we have to break sharing.
55 * Let's say we write to a shared block in what was the origin. The
58 * i) plug io further to this physical block. (see bio_prison code).
60 * ii) quiesce any read io to that shared data block. Obviously
61 * including all devices that share this block. (see dm_deferred_set code)
63 * iii) copy the data block to a newly allocate block. This step can be
64 * missed out if the io covers the block. (schedule_copy).
66 * iv) insert the new mapping into the origin's btree
67 * (process_prepared_mapping). This act of inserting breaks some
68 * sharing of btree nodes between the two devices. Breaking sharing only
69 * effects the btree of that specific device. Btrees for the other
70 * devices that share the block never change. The btree for the origin
71 * device as it was after the last commit is untouched, ie. we're using
72 * persistent data structures in the functional programming sense.
74 * v) unplug io to this physical block, including the io that triggered
75 * the breaking of sharing.
77 * Steps (ii) and (iii) occur in parallel.
79 * The metadata _doesn't_ need to be committed before the io continues. We
80 * get away with this because the io is always written to a _new_ block.
81 * If there's a crash, then:
83 * - The origin mapping will point to the old origin block (the shared
84 * one). This will contain the data as it was before the io that triggered
85 * the breaking of sharing came in.
87 * - The snap mapping still points to the old block. As it would after
90 * The downside of this scheme is the timestamp magic isn't perfect, and
91 * will continue to think that data block in the snapshot device is shared
92 * even after the write to the origin has broken sharing. I suspect data
93 * blocks will typically be shared by many different devices, so we're
94 * breaking sharing n + 1 times, rather than n, where n is the number of
95 * devices that reference this data block. At the moment I think the
96 * benefits far, far outweigh the disadvantages.
99 /*----------------------------------------------------------------*/
104 static void build_data_key(struct dm_thin_device *td,
105 dm_block_t b, struct dm_cell_key *key)
108 key->dev = dm_thin_dev_id(td);
112 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
113 struct dm_cell_key *key)
116 key->dev = dm_thin_dev_id(td);
120 /*----------------------------------------------------------------*/
123 * A pool device ties together a metadata device and a data device. It
124 * also provides the interface for creating and destroying internal
127 struct dm_thin_new_mapping;
130 * The pool runs in 3 modes. Ordered in degraded order for comparisons.
133 PM_WRITE, /* metadata may be changed */
134 PM_READ_ONLY, /* metadata may not be changed */
135 PM_FAIL, /* all I/O fails */
138 struct pool_features {
141 bool zero_new_blocks:1;
142 bool discard_enabled:1;
143 bool discard_passdown:1;
147 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
148 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
151 struct list_head list;
152 struct dm_target *ti; /* Only set if a pool target is bound */
154 struct mapped_device *pool_md;
155 struct block_device *md_dev;
156 struct dm_pool_metadata *pmd;
158 dm_block_t low_water_blocks;
159 uint32_t sectors_per_block;
160 int sectors_per_block_shift;
162 struct pool_features pf;
163 unsigned low_water_triggered:1; /* A dm event has been sent */
164 unsigned no_free_space:1; /* A -ENOSPC warning has been issued */
166 struct dm_bio_prison *prison;
167 struct dm_kcopyd_client *copier;
169 struct workqueue_struct *wq;
170 struct work_struct worker;
171 struct delayed_work waker;
173 unsigned long last_commit_jiffies;
177 struct bio_list deferred_bios;
178 struct bio_list deferred_flush_bios;
179 struct list_head prepared_mappings;
180 struct list_head prepared_discards;
182 struct bio_list retry_on_resume_list;
184 struct dm_deferred_set *shared_read_ds;
185 struct dm_deferred_set *all_io_ds;
187 struct dm_thin_new_mapping *next_mapping;
188 mempool_t *mapping_pool;
189 mempool_t *endio_hook_pool;
191 process_bio_fn process_bio;
192 process_bio_fn process_discard;
194 process_mapping_fn process_prepared_mapping;
195 process_mapping_fn process_prepared_discard;
198 static enum pool_mode get_pool_mode(struct pool *pool);
199 static void set_pool_mode(struct pool *pool, enum pool_mode mode);
202 * Target context for a pool.
205 struct dm_target *ti;
207 struct dm_dev *data_dev;
208 struct dm_dev *metadata_dev;
209 struct dm_target_callbacks callbacks;
211 dm_block_t low_water_blocks;
212 struct pool_features requested_pf; /* Features requested during table load */
213 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
217 * Target context for a thin.
220 struct dm_dev *pool_dev;
221 struct dm_dev *origin_dev;
225 struct dm_thin_device *td;
228 /*----------------------------------------------------------------*/
231 * A global list of pools that uses a struct mapped_device as a key.
233 static struct dm_thin_pool_table {
235 struct list_head pools;
236 } dm_thin_pool_table;
238 static void pool_table_init(void)
240 mutex_init(&dm_thin_pool_table.mutex);
241 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
244 static void __pool_table_insert(struct pool *pool)
246 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
247 list_add(&pool->list, &dm_thin_pool_table.pools);
250 static void __pool_table_remove(struct pool *pool)
252 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
253 list_del(&pool->list);
256 static struct pool *__pool_table_lookup(struct mapped_device *md)
258 struct pool *pool = NULL, *tmp;
260 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
262 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
263 if (tmp->pool_md == md) {
272 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
274 struct pool *pool = NULL, *tmp;
276 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
278 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
279 if (tmp->md_dev == md_dev) {
288 /*----------------------------------------------------------------*/
290 struct dm_thin_endio_hook {
292 struct dm_deferred_entry *shared_read_entry;
293 struct dm_deferred_entry *all_io_entry;
294 struct dm_thin_new_mapping *overwrite_mapping;
297 static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
300 struct bio_list bios;
302 bio_list_init(&bios);
303 bio_list_merge(&bios, master);
304 bio_list_init(master);
306 while ((bio = bio_list_pop(&bios))) {
307 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
310 bio_endio(bio, DM_ENDIO_REQUEUE);
312 bio_list_add(master, bio);
316 static void requeue_io(struct thin_c *tc)
318 struct pool *pool = tc->pool;
321 spin_lock_irqsave(&pool->lock, flags);
322 __requeue_bio_list(tc, &pool->deferred_bios);
323 __requeue_bio_list(tc, &pool->retry_on_resume_list);
324 spin_unlock_irqrestore(&pool->lock, flags);
328 * This section of code contains the logic for processing a thin device's IO.
329 * Much of the code depends on pool object resources (lists, workqueues, etc)
330 * but most is exclusively called from the thin target rather than the thin-pool
334 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
336 sector_t block_nr = bio->bi_sector;
338 if (tc->pool->sectors_per_block_shift < 0)
339 (void) sector_div(block_nr, tc->pool->sectors_per_block);
341 block_nr >>= tc->pool->sectors_per_block_shift;
346 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
348 struct pool *pool = tc->pool;
349 sector_t bi_sector = bio->bi_sector;
351 bio->bi_bdev = tc->pool_dev->bdev;
352 if (tc->pool->sectors_per_block_shift < 0)
353 bio->bi_sector = (block * pool->sectors_per_block) +
354 sector_div(bi_sector, pool->sectors_per_block);
356 bio->bi_sector = (block << pool->sectors_per_block_shift) |
357 (bi_sector & (pool->sectors_per_block - 1));
360 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
362 bio->bi_bdev = tc->origin_dev->bdev;
365 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
367 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
368 dm_thin_changed_this_transaction(tc->td);
371 static void inc_all_io_entry(struct pool *pool, struct bio *bio)
373 struct dm_thin_endio_hook *h;
375 if (bio->bi_rw & REQ_DISCARD)
378 h = dm_get_mapinfo(bio)->ptr;
379 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
382 static void issue(struct thin_c *tc, struct bio *bio)
384 struct pool *pool = tc->pool;
387 if (!bio_triggers_commit(tc, bio)) {
388 generic_make_request(bio);
393 * Complete bio with an error if earlier I/O caused changes to
394 * the metadata that can't be committed e.g, due to I/O errors
395 * on the metadata device.
397 if (dm_thin_aborted_changes(tc->td)) {
403 * Batch together any bios that trigger commits and then issue a
404 * single commit for them in process_deferred_bios().
406 spin_lock_irqsave(&pool->lock, flags);
407 bio_list_add(&pool->deferred_flush_bios, bio);
408 spin_unlock_irqrestore(&pool->lock, flags);
411 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
413 remap_to_origin(tc, bio);
417 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
420 remap(tc, bio, block);
425 * wake_worker() is used when new work is queued and when pool_resume is
426 * ready to continue deferred IO processing.
428 static void wake_worker(struct pool *pool)
430 queue_work(pool->wq, &pool->worker);
433 /*----------------------------------------------------------------*/
436 * Bio endio functions.
438 struct dm_thin_new_mapping {
439 struct list_head list;
443 unsigned pass_discard:1;
446 dm_block_t virt_block;
447 dm_block_t data_block;
448 struct dm_bio_prison_cell *cell, *cell2;
452 * If the bio covers the whole area of a block then we can avoid
453 * zeroing or copying. Instead this bio is hooked. The bio will
454 * still be in the cell, so care has to be taken to avoid issuing
458 bio_end_io_t *saved_bi_end_io;
461 static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
463 struct pool *pool = m->tc->pool;
465 if (m->quiesced && m->prepared) {
466 list_add(&m->list, &pool->prepared_mappings);
471 static void copy_complete(int read_err, unsigned long write_err, void *context)
474 struct dm_thin_new_mapping *m = context;
475 struct pool *pool = m->tc->pool;
477 m->err = read_err || write_err ? -EIO : 0;
479 spin_lock_irqsave(&pool->lock, flags);
481 __maybe_add_mapping(m);
482 spin_unlock_irqrestore(&pool->lock, flags);
485 static void overwrite_endio(struct bio *bio, int err)
488 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
489 struct dm_thin_new_mapping *m = h->overwrite_mapping;
490 struct pool *pool = m->tc->pool;
494 spin_lock_irqsave(&pool->lock, flags);
496 __maybe_add_mapping(m);
497 spin_unlock_irqrestore(&pool->lock, flags);
500 /*----------------------------------------------------------------*/
507 * Prepared mapping jobs.
511 * This sends the bios in the cell back to the deferred_bios list.
513 static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell,
514 dm_block_t data_block)
516 struct pool *pool = tc->pool;
519 spin_lock_irqsave(&pool->lock, flags);
520 dm_cell_release(cell, &pool->deferred_bios);
521 spin_unlock_irqrestore(&tc->pool->lock, flags);
527 * Same as cell_defer except it omits the original holder of the cell.
529 static void cell_defer_except(struct thin_c *tc, struct dm_bio_prison_cell *cell)
531 struct bio_list bios;
532 struct pool *pool = tc->pool;
535 bio_list_init(&bios);
537 spin_lock_irqsave(&pool->lock, flags);
538 dm_cell_release_no_holder(cell, &pool->deferred_bios);
539 spin_unlock_irqrestore(&pool->lock, flags);
544 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
547 m->bio->bi_end_io = m->saved_bi_end_io;
548 dm_cell_error(m->cell);
550 mempool_free(m, m->tc->pool->mapping_pool);
552 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
554 struct thin_c *tc = m->tc;
560 bio->bi_end_io = m->saved_bi_end_io;
563 dm_cell_error(m->cell);
568 * Commit the prepared block into the mapping btree.
569 * Any I/O for this block arriving after this point will get
570 * remapped to it directly.
572 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
574 DMERR("dm_thin_insert_block() failed");
575 dm_cell_error(m->cell);
580 * Release any bios held while the block was being provisioned.
581 * If we are processing a write bio that completely covers the block,
582 * we already processed it so can ignore it now when processing
583 * the bios in the cell.
586 cell_defer_except(tc, m->cell);
589 cell_defer(tc, m->cell, m->data_block);
593 mempool_free(m, tc->pool->mapping_pool);
596 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
598 struct thin_c *tc = m->tc;
600 bio_io_error(m->bio);
601 cell_defer_except(tc, m->cell);
602 cell_defer_except(tc, m->cell2);
603 mempool_free(m, tc->pool->mapping_pool);
606 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
608 struct thin_c *tc = m->tc;
610 inc_all_io_entry(tc->pool, m->bio);
611 cell_defer_except(tc, m->cell);
612 cell_defer_except(tc, m->cell2);
615 remap_and_issue(tc, m->bio, m->data_block);
617 bio_endio(m->bio, 0);
619 mempool_free(m, tc->pool->mapping_pool);
622 static void process_prepared_discard(struct dm_thin_new_mapping *m)
625 struct thin_c *tc = m->tc;
627 r = dm_thin_remove_block(tc->td, m->virt_block);
629 DMERR("dm_thin_remove_block() failed");
631 process_prepared_discard_passdown(m);
634 static void process_prepared(struct pool *pool, struct list_head *head,
635 process_mapping_fn *fn)
638 struct list_head maps;
639 struct dm_thin_new_mapping *m, *tmp;
641 INIT_LIST_HEAD(&maps);
642 spin_lock_irqsave(&pool->lock, flags);
643 list_splice_init(head, &maps);
644 spin_unlock_irqrestore(&pool->lock, flags);
646 list_for_each_entry_safe(m, tmp, &maps, list)
653 static int io_overlaps_block(struct pool *pool, struct bio *bio)
655 return bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT);
658 static int io_overwrites_block(struct pool *pool, struct bio *bio)
660 return (bio_data_dir(bio) == WRITE) &&
661 io_overlaps_block(pool, bio);
664 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
667 *save = bio->bi_end_io;
671 static int ensure_next_mapping(struct pool *pool)
673 if (pool->next_mapping)
676 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
678 return pool->next_mapping ? 0 : -ENOMEM;
681 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
683 struct dm_thin_new_mapping *r = pool->next_mapping;
685 BUG_ON(!pool->next_mapping);
687 pool->next_mapping = NULL;
692 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
693 struct dm_dev *origin, dm_block_t data_origin,
694 dm_block_t data_dest,
695 struct dm_bio_prison_cell *cell, struct bio *bio)
698 struct pool *pool = tc->pool;
699 struct dm_thin_new_mapping *m = get_next_mapping(pool);
701 INIT_LIST_HEAD(&m->list);
705 m->virt_block = virt_block;
706 m->data_block = data_dest;
711 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
715 * IO to pool_dev remaps to the pool target's data_dev.
717 * If the whole block of data is being overwritten, we can issue the
718 * bio immediately. Otherwise we use kcopyd to clone the data first.
720 if (io_overwrites_block(pool, bio)) {
721 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
723 h->overwrite_mapping = m;
725 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
726 inc_all_io_entry(pool, bio);
727 remap_and_issue(tc, bio, data_dest);
729 struct dm_io_region from, to;
731 from.bdev = origin->bdev;
732 from.sector = data_origin * pool->sectors_per_block;
733 from.count = pool->sectors_per_block;
735 to.bdev = tc->pool_dev->bdev;
736 to.sector = data_dest * pool->sectors_per_block;
737 to.count = pool->sectors_per_block;
739 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
740 0, copy_complete, m);
742 mempool_free(m, pool->mapping_pool);
743 DMERR("dm_kcopyd_copy() failed");
749 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
750 dm_block_t data_origin, dm_block_t data_dest,
751 struct dm_bio_prison_cell *cell, struct bio *bio)
753 schedule_copy(tc, virt_block, tc->pool_dev,
754 data_origin, data_dest, cell, bio);
757 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
758 dm_block_t data_dest,
759 struct dm_bio_prison_cell *cell, struct bio *bio)
761 schedule_copy(tc, virt_block, tc->origin_dev,
762 virt_block, data_dest, cell, bio);
765 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
766 dm_block_t data_block, struct dm_bio_prison_cell *cell,
769 struct pool *pool = tc->pool;
770 struct dm_thin_new_mapping *m = get_next_mapping(pool);
772 INIT_LIST_HEAD(&m->list);
776 m->virt_block = virt_block;
777 m->data_block = data_block;
783 * If the whole block of data is being overwritten or we are not
784 * zeroing pre-existing data, we can issue the bio immediately.
785 * Otherwise we use kcopyd to zero the data first.
787 if (!pool->pf.zero_new_blocks)
788 process_prepared_mapping(m);
790 else if (io_overwrites_block(pool, bio)) {
791 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
793 h->overwrite_mapping = m;
795 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
796 inc_all_io_entry(pool, bio);
797 remap_and_issue(tc, bio, data_block);
800 struct dm_io_region to;
802 to.bdev = tc->pool_dev->bdev;
803 to.sector = data_block * pool->sectors_per_block;
804 to.count = pool->sectors_per_block;
806 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
808 mempool_free(m, pool->mapping_pool);
809 DMERR("dm_kcopyd_zero() failed");
815 static int commit(struct pool *pool)
819 r = dm_pool_commit_metadata(pool->pmd);
821 DMERR("commit failed, error = %d", r);
827 * A non-zero return indicates read_only or fail_io mode.
828 * Many callers don't care about the return value.
830 static int commit_or_fallback(struct pool *pool)
834 if (get_pool_mode(pool) != PM_WRITE)
839 set_pool_mode(pool, PM_READ_ONLY);
844 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
847 dm_block_t free_blocks;
849 struct pool *pool = tc->pool;
851 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
855 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
856 DMWARN("%s: reached low water mark, sending event.",
857 dm_device_name(pool->pool_md));
858 spin_lock_irqsave(&pool->lock, flags);
859 pool->low_water_triggered = 1;
860 spin_unlock_irqrestore(&pool->lock, flags);
861 dm_table_event(pool->ti->table);
865 if (pool->no_free_space)
869 * Try to commit to see if that will free up some
872 (void) commit_or_fallback(pool);
874 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
879 * If we still have no space we set a flag to avoid
880 * doing all this checking and return -ENOSPC.
883 DMWARN("%s: no free space available.",
884 dm_device_name(pool->pool_md));
885 spin_lock_irqsave(&pool->lock, flags);
886 pool->no_free_space = 1;
887 spin_unlock_irqrestore(&pool->lock, flags);
893 r = dm_pool_alloc_data_block(pool->pmd, result);
901 * If we have run out of space, queue bios until the device is
902 * resumed, presumably after having been reloaded with more space.
904 static void retry_on_resume(struct bio *bio)
906 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
907 struct thin_c *tc = h->tc;
908 struct pool *pool = tc->pool;
911 spin_lock_irqsave(&pool->lock, flags);
912 bio_list_add(&pool->retry_on_resume_list, bio);
913 spin_unlock_irqrestore(&pool->lock, flags);
916 static void no_space(struct dm_bio_prison_cell *cell)
919 struct bio_list bios;
921 bio_list_init(&bios);
922 dm_cell_release(cell, &bios);
924 while ((bio = bio_list_pop(&bios)))
925 retry_on_resume(bio);
928 static void process_discard(struct thin_c *tc, struct bio *bio)
932 struct pool *pool = tc->pool;
933 struct dm_bio_prison_cell *cell, *cell2;
934 struct dm_cell_key key, key2;
935 dm_block_t block = get_bio_block(tc, bio);
936 struct dm_thin_lookup_result lookup_result;
937 struct dm_thin_new_mapping *m;
939 build_virtual_key(tc->td, block, &key);
940 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell))
943 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
947 * Check nobody is fiddling with this pool block. This can
948 * happen if someone's in the process of breaking sharing
951 build_data_key(tc->td, lookup_result.block, &key2);
952 if (dm_bio_detain(tc->pool->prison, &key2, bio, &cell2)) {
953 cell_defer_except(tc, cell);
957 if (io_overlaps_block(pool, bio)) {
959 * IO may still be going to the destination block. We must
960 * quiesce before we can do the removal.
962 m = get_next_mapping(pool);
964 m->pass_discard = (!lookup_result.shared) && pool->pf.discard_passdown;
965 m->virt_block = block;
966 m->data_block = lookup_result.block;
972 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
973 spin_lock_irqsave(&pool->lock, flags);
974 list_add(&m->list, &pool->prepared_discards);
975 spin_unlock_irqrestore(&pool->lock, flags);
979 inc_all_io_entry(pool, bio);
980 cell_defer_except(tc, cell);
981 cell_defer_except(tc, cell2);
984 * The DM core makes sure that the discard doesn't span
985 * a block boundary. So we submit the discard of a
986 * partial block appropriately.
988 if ((!lookup_result.shared) && pool->pf.discard_passdown)
989 remap_and_issue(tc, bio, lookup_result.block);
997 * It isn't provisioned, just forget it.
999 cell_defer_except(tc, cell);
1004 DMERR("discard: find block unexpectedly returned %d", r);
1005 cell_defer_except(tc, cell);
1011 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1012 struct dm_cell_key *key,
1013 struct dm_thin_lookup_result *lookup_result,
1014 struct dm_bio_prison_cell *cell)
1017 dm_block_t data_block;
1019 r = alloc_data_block(tc, &data_block);
1022 schedule_internal_copy(tc, block, lookup_result->block,
1023 data_block, cell, bio);
1031 DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
1032 dm_cell_error(cell);
1037 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1039 struct dm_thin_lookup_result *lookup_result)
1041 struct dm_bio_prison_cell *cell;
1042 struct pool *pool = tc->pool;
1043 struct dm_cell_key key;
1046 * If cell is already occupied, then sharing is already in the process
1047 * of being broken so we have nothing further to do here.
1049 build_data_key(tc->td, lookup_result->block, &key);
1050 if (dm_bio_detain(pool->prison, &key, bio, &cell))
1053 if (bio_data_dir(bio) == WRITE && bio->bi_size)
1054 break_sharing(tc, bio, block, &key, lookup_result, cell);
1056 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
1058 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1059 inc_all_io_entry(pool, bio);
1060 cell_defer_except(tc, cell);
1062 remap_and_issue(tc, bio, lookup_result->block);
1066 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1067 struct dm_bio_prison_cell *cell)
1070 dm_block_t data_block;
1073 * Remap empty bios (flushes) immediately, without provisioning.
1075 if (!bio->bi_size) {
1076 inc_all_io_entry(tc->pool, bio);
1077 cell_defer_except(tc, cell);
1079 remap_and_issue(tc, bio, 0);
1084 * Fill read bios with zeroes and complete them immediately.
1086 if (bio_data_dir(bio) == READ) {
1088 cell_defer_except(tc, cell);
1093 r = alloc_data_block(tc, &data_block);
1097 schedule_external_copy(tc, block, data_block, cell, bio);
1099 schedule_zero(tc, block, data_block, cell, bio);
1107 DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
1108 set_pool_mode(tc->pool, PM_READ_ONLY);
1109 dm_cell_error(cell);
1114 static void process_bio(struct thin_c *tc, struct bio *bio)
1117 dm_block_t block = get_bio_block(tc, bio);
1118 struct dm_bio_prison_cell *cell;
1119 struct dm_cell_key key;
1120 struct dm_thin_lookup_result lookup_result;
1123 * If cell is already occupied, then the block is already
1124 * being provisioned so we have nothing further to do here.
1126 build_virtual_key(tc->td, block, &key);
1127 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell))
1130 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1133 if (lookup_result.shared) {
1134 process_shared_bio(tc, bio, block, &lookup_result);
1135 cell_defer_except(tc, cell);
1137 inc_all_io_entry(tc->pool, bio);
1138 cell_defer_except(tc, cell);
1140 remap_and_issue(tc, bio, lookup_result.block);
1145 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1146 inc_all_io_entry(tc->pool, bio);
1147 cell_defer_except(tc, cell);
1149 remap_to_origin_and_issue(tc, bio);
1151 provision_block(tc, bio, block, cell);
1155 DMERR("dm_thin_find_block() failed, error = %d", r);
1156 cell_defer_except(tc, cell);
1162 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1165 int rw = bio_data_dir(bio);
1166 dm_block_t block = get_bio_block(tc, bio);
1167 struct dm_thin_lookup_result lookup_result;
1169 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1172 if (lookup_result.shared && (rw == WRITE) && bio->bi_size)
1175 inc_all_io_entry(tc->pool, bio);
1176 remap_and_issue(tc, bio, lookup_result.block);
1186 if (tc->origin_dev) {
1187 inc_all_io_entry(tc->pool, bio);
1188 remap_to_origin_and_issue(tc, bio);
1197 DMERR("dm_thin_find_block() failed, error = %d", r);
1203 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1208 static int need_commit_due_to_time(struct pool *pool)
1210 return jiffies < pool->last_commit_jiffies ||
1211 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1214 static void process_deferred_bios(struct pool *pool)
1216 unsigned long flags;
1218 struct bio_list bios;
1220 bio_list_init(&bios);
1222 spin_lock_irqsave(&pool->lock, flags);
1223 bio_list_merge(&bios, &pool->deferred_bios);
1224 bio_list_init(&pool->deferred_bios);
1225 spin_unlock_irqrestore(&pool->lock, flags);
1227 while ((bio = bio_list_pop(&bios))) {
1228 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
1229 struct thin_c *tc = h->tc;
1232 * If we've got no free new_mapping structs, and processing
1233 * this bio might require one, we pause until there are some
1234 * prepared mappings to process.
1236 if (ensure_next_mapping(pool)) {
1237 spin_lock_irqsave(&pool->lock, flags);
1238 bio_list_merge(&pool->deferred_bios, &bios);
1239 spin_unlock_irqrestore(&pool->lock, flags);
1244 if (bio->bi_rw & REQ_DISCARD)
1245 pool->process_discard(tc, bio);
1247 pool->process_bio(tc, bio);
1251 * If there are any deferred flush bios, we must commit
1252 * the metadata before issuing them.
1254 bio_list_init(&bios);
1255 spin_lock_irqsave(&pool->lock, flags);
1256 bio_list_merge(&bios, &pool->deferred_flush_bios);
1257 bio_list_init(&pool->deferred_flush_bios);
1258 spin_unlock_irqrestore(&pool->lock, flags);
1260 if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))
1263 if (commit_or_fallback(pool)) {
1264 while ((bio = bio_list_pop(&bios)))
1268 pool->last_commit_jiffies = jiffies;
1270 while ((bio = bio_list_pop(&bios)))
1271 generic_make_request(bio);
1274 static void do_worker(struct work_struct *ws)
1276 struct pool *pool = container_of(ws, struct pool, worker);
1278 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1279 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1280 process_deferred_bios(pool);
1284 * We want to commit periodically so that not too much
1285 * unwritten data builds up.
1287 static void do_waker(struct work_struct *ws)
1289 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1291 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1294 /*----------------------------------------------------------------*/
1296 static enum pool_mode get_pool_mode(struct pool *pool)
1298 return pool->pf.mode;
1301 static void set_pool_mode(struct pool *pool, enum pool_mode mode)
1305 pool->pf.mode = mode;
1309 DMERR("switching pool to failure mode");
1310 pool->process_bio = process_bio_fail;
1311 pool->process_discard = process_bio_fail;
1312 pool->process_prepared_mapping = process_prepared_mapping_fail;
1313 pool->process_prepared_discard = process_prepared_discard_fail;
1317 DMERR("switching pool to read-only mode");
1318 r = dm_pool_abort_metadata(pool->pmd);
1320 DMERR("aborting transaction failed");
1321 set_pool_mode(pool, PM_FAIL);
1323 dm_pool_metadata_read_only(pool->pmd);
1324 pool->process_bio = process_bio_read_only;
1325 pool->process_discard = process_discard;
1326 pool->process_prepared_mapping = process_prepared_mapping_fail;
1327 pool->process_prepared_discard = process_prepared_discard_passdown;
1332 pool->process_bio = process_bio;
1333 pool->process_discard = process_discard;
1334 pool->process_prepared_mapping = process_prepared_mapping;
1335 pool->process_prepared_discard = process_prepared_discard;
1340 /*----------------------------------------------------------------*/
1343 * Mapping functions.
1347 * Called only while mapping a thin bio to hand it over to the workqueue.
1349 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1351 unsigned long flags;
1352 struct pool *pool = tc->pool;
1354 spin_lock_irqsave(&pool->lock, flags);
1355 bio_list_add(&pool->deferred_bios, bio);
1356 spin_unlock_irqrestore(&pool->lock, flags);
1361 static struct dm_thin_endio_hook *thin_hook_bio(struct thin_c *tc, struct bio *bio)
1363 struct pool *pool = tc->pool;
1364 struct dm_thin_endio_hook *h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO);
1367 h->shared_read_entry = NULL;
1368 h->all_io_entry = NULL;
1369 h->overwrite_mapping = NULL;
1375 * Non-blocking function called from the thin target's map function.
1377 static int thin_bio_map(struct dm_target *ti, struct bio *bio,
1378 union map_info *map_context)
1381 struct thin_c *tc = ti->private;
1382 dm_block_t block = get_bio_block(tc, bio);
1383 struct dm_thin_device *td = tc->td;
1384 struct dm_thin_lookup_result result;
1385 struct dm_bio_prison_cell *cell1, *cell2;
1386 struct dm_cell_key key;
1388 map_context->ptr = thin_hook_bio(tc, bio);
1390 if (get_pool_mode(tc->pool) == PM_FAIL) {
1392 return DM_MAPIO_SUBMITTED;
1395 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
1396 thin_defer_bio(tc, bio);
1397 return DM_MAPIO_SUBMITTED;
1400 r = dm_thin_find_block(td, block, 0, &result);
1403 * Note that we defer readahead too.
1407 if (unlikely(result.shared)) {
1409 * We have a race condition here between the
1410 * result.shared value returned by the lookup and
1411 * snapshot creation, which may cause new
1414 * To avoid this always quiesce the origin before
1415 * taking the snap. You want to do this anyway to
1416 * ensure a consistent application view
1419 * More distant ancestors are irrelevant. The
1420 * shared flag will be set in their case.
1422 thin_defer_bio(tc, bio);
1423 return DM_MAPIO_SUBMITTED;
1426 build_virtual_key(tc->td, block, &key);
1427 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1))
1428 return DM_MAPIO_SUBMITTED;
1430 build_data_key(tc->td, result.block, &key);
1431 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2)) {
1432 cell_defer_except(tc, cell1);
1433 return DM_MAPIO_SUBMITTED;
1436 inc_all_io_entry(tc->pool, bio);
1437 cell_defer_except(tc, cell2);
1438 cell_defer_except(tc, cell1);
1440 remap(tc, bio, result.block);
1441 return DM_MAPIO_REMAPPED;
1444 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
1446 * This block isn't provisioned, and we have no way
1447 * of doing so. Just error it.
1450 r = DM_MAPIO_SUBMITTED;
1457 * In future, the failed dm_thin_find_block above could
1458 * provide the hint to load the metadata into cache.
1460 thin_defer_bio(tc, bio);
1461 r = DM_MAPIO_SUBMITTED;
1466 * Must always call bio_io_error on failure.
1467 * dm_thin_find_block can fail with -EINVAL if the
1468 * pool is switched to fail-io mode.
1471 r = DM_MAPIO_SUBMITTED;
1478 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1481 unsigned long flags;
1482 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1484 spin_lock_irqsave(&pt->pool->lock, flags);
1485 r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1486 spin_unlock_irqrestore(&pt->pool->lock, flags);
1489 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1490 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1496 static void __requeue_bios(struct pool *pool)
1498 bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1499 bio_list_init(&pool->retry_on_resume_list);
1502 /*----------------------------------------------------------------
1503 * Binding of control targets to a pool object
1504 *--------------------------------------------------------------*/
1505 static bool data_dev_supports_discard(struct pool_c *pt)
1507 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1509 return q && blk_queue_discard(q);
1513 * If discard_passdown was enabled verify that the data device
1514 * supports discards. Disable discard_passdown if not.
1516 static void disable_passdown_if_not_supported(struct pool_c *pt)
1518 struct pool *pool = pt->pool;
1519 struct block_device *data_bdev = pt->data_dev->bdev;
1520 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
1521 sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
1522 const char *reason = NULL;
1523 char buf[BDEVNAME_SIZE];
1525 if (!pt->adjusted_pf.discard_passdown)
1528 if (!data_dev_supports_discard(pt))
1529 reason = "discard unsupported";
1531 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
1532 reason = "max discard sectors smaller than a block";
1534 else if (data_limits->discard_granularity > block_size)
1535 reason = "discard granularity larger than a block";
1537 else if (block_size & (data_limits->discard_granularity - 1))
1538 reason = "discard granularity not a factor of block size";
1541 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
1542 pt->adjusted_pf.discard_passdown = false;
1546 static int bind_control_target(struct pool *pool, struct dm_target *ti)
1548 struct pool_c *pt = ti->private;
1551 * We want to make sure that degraded pools are never upgraded.
1553 enum pool_mode old_mode = pool->pf.mode;
1554 enum pool_mode new_mode = pt->adjusted_pf.mode;
1556 if (old_mode > new_mode)
1557 new_mode = old_mode;
1560 pool->low_water_blocks = pt->low_water_blocks;
1561 pool->pf = pt->adjusted_pf;
1563 set_pool_mode(pool, new_mode);
1568 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1574 /*----------------------------------------------------------------
1576 *--------------------------------------------------------------*/
1577 /* Initialize pool features. */
1578 static void pool_features_init(struct pool_features *pf)
1580 pf->mode = PM_WRITE;
1581 pf->zero_new_blocks = true;
1582 pf->discard_enabled = true;
1583 pf->discard_passdown = true;
1586 static void __pool_destroy(struct pool *pool)
1588 __pool_table_remove(pool);
1590 if (dm_pool_metadata_close(pool->pmd) < 0)
1591 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1593 dm_bio_prison_destroy(pool->prison);
1594 dm_kcopyd_client_destroy(pool->copier);
1597 destroy_workqueue(pool->wq);
1599 if (pool->next_mapping)
1600 mempool_free(pool->next_mapping, pool->mapping_pool);
1601 mempool_destroy(pool->mapping_pool);
1602 mempool_destroy(pool->endio_hook_pool);
1603 dm_deferred_set_destroy(pool->shared_read_ds);
1604 dm_deferred_set_destroy(pool->all_io_ds);
1608 static struct kmem_cache *_new_mapping_cache;
1609 static struct kmem_cache *_endio_hook_cache;
1611 static struct pool *pool_create(struct mapped_device *pool_md,
1612 struct block_device *metadata_dev,
1613 unsigned long block_size,
1614 int read_only, char **error)
1619 struct dm_pool_metadata *pmd;
1620 bool format_device = read_only ? false : true;
1622 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
1624 *error = "Error creating metadata object";
1625 return (struct pool *)pmd;
1628 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1630 *error = "Error allocating memory for pool";
1631 err_p = ERR_PTR(-ENOMEM);
1636 pool->sectors_per_block = block_size;
1637 if (block_size & (block_size - 1))
1638 pool->sectors_per_block_shift = -1;
1640 pool->sectors_per_block_shift = __ffs(block_size);
1641 pool->low_water_blocks = 0;
1642 pool_features_init(&pool->pf);
1643 pool->prison = dm_bio_prison_create(PRISON_CELLS);
1644 if (!pool->prison) {
1645 *error = "Error creating pool's bio prison";
1646 err_p = ERR_PTR(-ENOMEM);
1650 pool->copier = dm_kcopyd_client_create();
1651 if (IS_ERR(pool->copier)) {
1652 r = PTR_ERR(pool->copier);
1653 *error = "Error creating pool's kcopyd client";
1655 goto bad_kcopyd_client;
1659 * Create singlethreaded workqueue that will service all devices
1660 * that use this metadata.
1662 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1664 *error = "Error creating pool's workqueue";
1665 err_p = ERR_PTR(-ENOMEM);
1669 INIT_WORK(&pool->worker, do_worker);
1670 INIT_DELAYED_WORK(&pool->waker, do_waker);
1671 spin_lock_init(&pool->lock);
1672 bio_list_init(&pool->deferred_bios);
1673 bio_list_init(&pool->deferred_flush_bios);
1674 INIT_LIST_HEAD(&pool->prepared_mappings);
1675 INIT_LIST_HEAD(&pool->prepared_discards);
1676 pool->low_water_triggered = 0;
1677 pool->no_free_space = 0;
1678 bio_list_init(&pool->retry_on_resume_list);
1680 pool->shared_read_ds = dm_deferred_set_create();
1681 if (!pool->shared_read_ds) {
1682 *error = "Error creating pool's shared read deferred set";
1683 err_p = ERR_PTR(-ENOMEM);
1684 goto bad_shared_read_ds;
1687 pool->all_io_ds = dm_deferred_set_create();
1688 if (!pool->all_io_ds) {
1689 *error = "Error creating pool's all io deferred set";
1690 err_p = ERR_PTR(-ENOMEM);
1694 pool->next_mapping = NULL;
1695 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
1696 _new_mapping_cache);
1697 if (!pool->mapping_pool) {
1698 *error = "Error creating pool's mapping mempool";
1699 err_p = ERR_PTR(-ENOMEM);
1700 goto bad_mapping_pool;
1703 pool->endio_hook_pool = mempool_create_slab_pool(ENDIO_HOOK_POOL_SIZE,
1705 if (!pool->endio_hook_pool) {
1706 *error = "Error creating pool's endio_hook mempool";
1707 err_p = ERR_PTR(-ENOMEM);
1708 goto bad_endio_hook_pool;
1710 pool->ref_count = 1;
1711 pool->last_commit_jiffies = jiffies;
1712 pool->pool_md = pool_md;
1713 pool->md_dev = metadata_dev;
1714 __pool_table_insert(pool);
1718 bad_endio_hook_pool:
1719 mempool_destroy(pool->mapping_pool);
1721 dm_deferred_set_destroy(pool->all_io_ds);
1723 dm_deferred_set_destroy(pool->shared_read_ds);
1725 destroy_workqueue(pool->wq);
1727 dm_kcopyd_client_destroy(pool->copier);
1729 dm_bio_prison_destroy(pool->prison);
1733 if (dm_pool_metadata_close(pmd))
1734 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1739 static void __pool_inc(struct pool *pool)
1741 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1745 static void __pool_dec(struct pool *pool)
1747 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1748 BUG_ON(!pool->ref_count);
1749 if (!--pool->ref_count)
1750 __pool_destroy(pool);
1753 static struct pool *__pool_find(struct mapped_device *pool_md,
1754 struct block_device *metadata_dev,
1755 unsigned long block_size, int read_only,
1756 char **error, int *created)
1758 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1761 if (pool->pool_md != pool_md) {
1762 *error = "metadata device already in use by a pool";
1763 return ERR_PTR(-EBUSY);
1768 pool = __pool_table_lookup(pool_md);
1770 if (pool->md_dev != metadata_dev) {
1771 *error = "different pool cannot replace a pool";
1772 return ERR_PTR(-EINVAL);
1777 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
1785 /*----------------------------------------------------------------
1786 * Pool target methods
1787 *--------------------------------------------------------------*/
1788 static void pool_dtr(struct dm_target *ti)
1790 struct pool_c *pt = ti->private;
1792 mutex_lock(&dm_thin_pool_table.mutex);
1794 unbind_control_target(pt->pool, ti);
1795 __pool_dec(pt->pool);
1796 dm_put_device(ti, pt->metadata_dev);
1797 dm_put_device(ti, pt->data_dev);
1800 mutex_unlock(&dm_thin_pool_table.mutex);
1803 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
1804 struct dm_target *ti)
1808 const char *arg_name;
1810 static struct dm_arg _args[] = {
1811 {0, 3, "Invalid number of pool feature arguments"},
1815 * No feature arguments supplied.
1820 r = dm_read_arg_group(_args, as, &argc, &ti->error);
1824 while (argc && !r) {
1825 arg_name = dm_shift_arg(as);
1828 if (!strcasecmp(arg_name, "skip_block_zeroing"))
1829 pf->zero_new_blocks = false;
1831 else if (!strcasecmp(arg_name, "ignore_discard"))
1832 pf->discard_enabled = false;
1834 else if (!strcasecmp(arg_name, "no_discard_passdown"))
1835 pf->discard_passdown = false;
1837 else if (!strcasecmp(arg_name, "read_only"))
1838 pf->mode = PM_READ_ONLY;
1841 ti->error = "Unrecognised pool feature requested";
1851 * thin-pool <metadata dev> <data dev>
1852 * <data block size (sectors)>
1853 * <low water mark (blocks)>
1854 * [<#feature args> [<arg>]*]
1856 * Optional feature arguments are:
1857 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1858 * ignore_discard: disable discard
1859 * no_discard_passdown: don't pass discards down to the data device
1861 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
1863 int r, pool_created = 0;
1866 struct pool_features pf;
1867 struct dm_arg_set as;
1868 struct dm_dev *data_dev;
1869 unsigned long block_size;
1870 dm_block_t low_water_blocks;
1871 struct dm_dev *metadata_dev;
1872 sector_t metadata_dev_size;
1873 char b[BDEVNAME_SIZE];
1876 * FIXME Remove validation from scope of lock.
1878 mutex_lock(&dm_thin_pool_table.mutex);
1881 ti->error = "Invalid argument count";
1888 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev);
1890 ti->error = "Error opening metadata block device";
1894 metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT;
1895 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
1896 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1897 bdevname(metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
1899 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
1901 ti->error = "Error getting data device";
1905 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
1906 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
1907 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
1908 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
1909 ti->error = "Invalid block size";
1914 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
1915 ti->error = "Invalid low water mark";
1921 * Set default pool features.
1923 pool_features_init(&pf);
1925 dm_consume_args(&as, 4);
1926 r = parse_pool_features(&as, &pf, ti);
1930 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
1936 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
1937 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
1944 * 'pool_created' reflects whether this is the first table load.
1945 * Top level discard support is not allowed to be changed after
1946 * initial load. This would require a pool reload to trigger thin
1949 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
1950 ti->error = "Discard support cannot be disabled once enabled";
1952 goto out_flags_changed;
1957 pt->metadata_dev = metadata_dev;
1958 pt->data_dev = data_dev;
1959 pt->low_water_blocks = low_water_blocks;
1960 pt->adjusted_pf = pt->requested_pf = pf;
1961 ti->num_flush_requests = 1;
1964 * Only need to enable discards if the pool should pass
1965 * them down to the data device. The thin device's discard
1966 * processing will cause mappings to be removed from the btree.
1968 if (pf.discard_enabled && pf.discard_passdown) {
1969 ti->num_discard_requests = 1;
1972 * Setting 'discards_supported' circumvents the normal
1973 * stacking of discard limits (this keeps the pool and
1974 * thin devices' discard limits consistent).
1976 ti->discards_supported = true;
1977 ti->discard_zeroes_data_unsupported = true;
1981 pt->callbacks.congested_fn = pool_is_congested;
1982 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
1984 mutex_unlock(&dm_thin_pool_table.mutex);
1993 dm_put_device(ti, data_dev);
1995 dm_put_device(ti, metadata_dev);
1997 mutex_unlock(&dm_thin_pool_table.mutex);
2002 static int pool_map(struct dm_target *ti, struct bio *bio,
2003 union map_info *map_context)
2006 struct pool_c *pt = ti->private;
2007 struct pool *pool = pt->pool;
2008 unsigned long flags;
2011 * As this is a singleton target, ti->begin is always zero.
2013 spin_lock_irqsave(&pool->lock, flags);
2014 bio->bi_bdev = pt->data_dev->bdev;
2015 r = DM_MAPIO_REMAPPED;
2016 spin_unlock_irqrestore(&pool->lock, flags);
2022 * Retrieves the number of blocks of the data device from
2023 * the superblock and compares it to the actual device size,
2024 * thus resizing the data device in case it has grown.
2026 * This both copes with opening preallocated data devices in the ctr
2027 * being followed by a resume
2029 * calling the resume method individually after userspace has
2030 * grown the data device in reaction to a table event.
2032 static int pool_preresume(struct dm_target *ti)
2035 struct pool_c *pt = ti->private;
2036 struct pool *pool = pt->pool;
2037 sector_t data_size = ti->len;
2038 dm_block_t sb_data_size;
2041 * Take control of the pool object.
2043 r = bind_control_target(pool, ti);
2047 (void) sector_div(data_size, pool->sectors_per_block);
2049 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2051 DMERR("failed to retrieve data device size");
2055 if (data_size < sb_data_size) {
2056 DMERR("pool target too small, is %llu blocks (expected %llu)",
2057 (unsigned long long)data_size, sb_data_size);
2060 } else if (data_size > sb_data_size) {
2061 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2063 DMERR("failed to resize data device");
2064 /* FIXME Stricter than necessary: Rollback transaction instead here */
2065 set_pool_mode(pool, PM_READ_ONLY);
2069 (void) commit_or_fallback(pool);
2075 static void pool_resume(struct dm_target *ti)
2077 struct pool_c *pt = ti->private;
2078 struct pool *pool = pt->pool;
2079 unsigned long flags;
2081 spin_lock_irqsave(&pool->lock, flags);
2082 pool->low_water_triggered = 0;
2083 pool->no_free_space = 0;
2084 __requeue_bios(pool);
2085 spin_unlock_irqrestore(&pool->lock, flags);
2087 do_waker(&pool->waker.work);
2090 static void pool_postsuspend(struct dm_target *ti)
2092 struct pool_c *pt = ti->private;
2093 struct pool *pool = pt->pool;
2095 cancel_delayed_work(&pool->waker);
2096 flush_workqueue(pool->wq);
2097 (void) commit_or_fallback(pool);
2100 static int check_arg_count(unsigned argc, unsigned args_required)
2102 if (argc != args_required) {
2103 DMWARN("Message received with %u arguments instead of %u.",
2104 argc, args_required);
2111 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2113 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2114 *dev_id <= MAX_DEV_ID)
2118 DMWARN("Message received with invalid device id: %s", arg);
2123 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2128 r = check_arg_count(argc, 2);
2132 r = read_dev_id(argv[1], &dev_id, 1);
2136 r = dm_pool_create_thin(pool->pmd, dev_id);
2138 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2146 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2149 dm_thin_id origin_dev_id;
2152 r = check_arg_count(argc, 3);
2156 r = read_dev_id(argv[1], &dev_id, 1);
2160 r = read_dev_id(argv[2], &origin_dev_id, 1);
2164 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2166 DMWARN("Creation of new snapshot %s of device %s failed.",
2174 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2179 r = check_arg_count(argc, 2);
2183 r = read_dev_id(argv[1], &dev_id, 1);
2187 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2189 DMWARN("Deletion of thin device %s failed.", argv[1]);
2194 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2196 dm_thin_id old_id, new_id;
2199 r = check_arg_count(argc, 3);
2203 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2204 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2208 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2209 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2213 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2215 DMWARN("Failed to change transaction id from %s to %s.",
2223 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2227 r = check_arg_count(argc, 1);
2231 (void) commit_or_fallback(pool);
2233 r = dm_pool_reserve_metadata_snap(pool->pmd);
2235 DMWARN("reserve_metadata_snap message failed.");
2240 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2244 r = check_arg_count(argc, 1);
2248 r = dm_pool_release_metadata_snap(pool->pmd);
2250 DMWARN("release_metadata_snap message failed.");
2256 * Messages supported:
2257 * create_thin <dev_id>
2258 * create_snap <dev_id> <origin_id>
2260 * trim <dev_id> <new_size_in_sectors>
2261 * set_transaction_id <current_trans_id> <new_trans_id>
2262 * reserve_metadata_snap
2263 * release_metadata_snap
2265 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2268 struct pool_c *pt = ti->private;
2269 struct pool *pool = pt->pool;
2271 if (!strcasecmp(argv[0], "create_thin"))
2272 r = process_create_thin_mesg(argc, argv, pool);
2274 else if (!strcasecmp(argv[0], "create_snap"))
2275 r = process_create_snap_mesg(argc, argv, pool);
2277 else if (!strcasecmp(argv[0], "delete"))
2278 r = process_delete_mesg(argc, argv, pool);
2280 else if (!strcasecmp(argv[0], "set_transaction_id"))
2281 r = process_set_transaction_id_mesg(argc, argv, pool);
2283 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
2284 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
2286 else if (!strcasecmp(argv[0], "release_metadata_snap"))
2287 r = process_release_metadata_snap_mesg(argc, argv, pool);
2290 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2293 (void) commit_or_fallback(pool);
2298 static void emit_flags(struct pool_features *pf, char *result,
2299 unsigned sz, unsigned maxlen)
2301 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
2302 !pf->discard_passdown + (pf->mode == PM_READ_ONLY);
2303 DMEMIT("%u ", count);
2305 if (!pf->zero_new_blocks)
2306 DMEMIT("skip_block_zeroing ");
2308 if (!pf->discard_enabled)
2309 DMEMIT("ignore_discard ");
2311 if (!pf->discard_passdown)
2312 DMEMIT("no_discard_passdown ");
2314 if (pf->mode == PM_READ_ONLY)
2315 DMEMIT("read_only ");
2320 * <transaction id> <used metadata sectors>/<total metadata sectors>
2321 * <used data sectors>/<total data sectors> <held metadata root>
2323 static int pool_status(struct dm_target *ti, status_type_t type,
2324 unsigned status_flags, char *result, unsigned maxlen)
2328 uint64_t transaction_id;
2329 dm_block_t nr_free_blocks_data;
2330 dm_block_t nr_free_blocks_metadata;
2331 dm_block_t nr_blocks_data;
2332 dm_block_t nr_blocks_metadata;
2333 dm_block_t held_root;
2334 char buf[BDEVNAME_SIZE];
2335 char buf2[BDEVNAME_SIZE];
2336 struct pool_c *pt = ti->private;
2337 struct pool *pool = pt->pool;
2340 case STATUSTYPE_INFO:
2341 if (get_pool_mode(pool) == PM_FAIL) {
2346 /* Commit to ensure statistics aren't out-of-date */
2347 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
2348 (void) commit_or_fallback(pool);
2350 r = dm_pool_get_metadata_transaction_id(pool->pmd,
2355 r = dm_pool_get_free_metadata_block_count(pool->pmd,
2356 &nr_free_blocks_metadata);
2360 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2364 r = dm_pool_get_free_block_count(pool->pmd,
2365 &nr_free_blocks_data);
2369 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2373 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
2377 DMEMIT("%llu %llu/%llu %llu/%llu ",
2378 (unsigned long long)transaction_id,
2379 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2380 (unsigned long long)nr_blocks_metadata,
2381 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2382 (unsigned long long)nr_blocks_data);
2385 DMEMIT("%llu ", held_root);
2389 if (pool->pf.mode == PM_READ_ONLY)
2394 if (pool->pf.discard_enabled && pool->pf.discard_passdown)
2395 DMEMIT("discard_passdown");
2397 DMEMIT("no_discard_passdown");
2401 case STATUSTYPE_TABLE:
2402 DMEMIT("%s %s %lu %llu ",
2403 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2404 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2405 (unsigned long)pool->sectors_per_block,
2406 (unsigned long long)pt->low_water_blocks);
2407 emit_flags(&pt->requested_pf, result, sz, maxlen);
2414 static int pool_iterate_devices(struct dm_target *ti,
2415 iterate_devices_callout_fn fn, void *data)
2417 struct pool_c *pt = ti->private;
2419 return fn(ti, pt->data_dev, 0, ti->len, data);
2422 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2423 struct bio_vec *biovec, int max_size)
2425 struct pool_c *pt = ti->private;
2426 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2428 if (!q->merge_bvec_fn)
2431 bvm->bi_bdev = pt->data_dev->bdev;
2433 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2436 static bool block_size_is_power_of_two(struct pool *pool)
2438 return pool->sectors_per_block_shift >= 0;
2441 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
2443 struct pool *pool = pt->pool;
2444 struct queue_limits *data_limits;
2446 limits->max_discard_sectors = pool->sectors_per_block;
2449 * discard_granularity is just a hint, and not enforced.
2451 if (pt->adjusted_pf.discard_passdown) {
2452 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
2453 limits->discard_granularity = data_limits->discard_granularity;
2454 } else if (block_size_is_power_of_two(pool))
2455 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
2458 * Use largest power of 2 that is a factor of sectors_per_block
2459 * but at least DATA_DEV_BLOCK_SIZE_MIN_SECTORS.
2461 limits->discard_granularity = max(1 << (ffs(pool->sectors_per_block) - 1),
2462 DATA_DEV_BLOCK_SIZE_MIN_SECTORS) << SECTOR_SHIFT;
2465 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2467 struct pool_c *pt = ti->private;
2468 struct pool *pool = pt->pool;
2470 blk_limits_io_min(limits, 0);
2471 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2474 * pt->adjusted_pf is a staging area for the actual features to use.
2475 * They get transferred to the live pool in bind_control_target()
2476 * called from pool_preresume().
2478 if (!pt->adjusted_pf.discard_enabled)
2481 disable_passdown_if_not_supported(pt);
2483 set_discard_limits(pt, limits);
2486 static struct target_type pool_target = {
2487 .name = "thin-pool",
2488 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2489 DM_TARGET_IMMUTABLE,
2490 .version = {1, 5, 0},
2491 .module = THIS_MODULE,
2495 .postsuspend = pool_postsuspend,
2496 .preresume = pool_preresume,
2497 .resume = pool_resume,
2498 .message = pool_message,
2499 .status = pool_status,
2500 .merge = pool_merge,
2501 .iterate_devices = pool_iterate_devices,
2502 .io_hints = pool_io_hints,
2505 /*----------------------------------------------------------------
2506 * Thin target methods
2507 *--------------------------------------------------------------*/
2508 static void thin_dtr(struct dm_target *ti)
2510 struct thin_c *tc = ti->private;
2512 mutex_lock(&dm_thin_pool_table.mutex);
2514 __pool_dec(tc->pool);
2515 dm_pool_close_thin_device(tc->td);
2516 dm_put_device(ti, tc->pool_dev);
2518 dm_put_device(ti, tc->origin_dev);
2521 mutex_unlock(&dm_thin_pool_table.mutex);
2525 * Thin target parameters:
2527 * <pool_dev> <dev_id> [origin_dev]
2529 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2530 * dev_id: the internal device identifier
2531 * origin_dev: a device external to the pool that should act as the origin
2533 * If the pool device has discards disabled, they get disabled for the thin
2536 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2540 struct dm_dev *pool_dev, *origin_dev;
2541 struct mapped_device *pool_md;
2543 mutex_lock(&dm_thin_pool_table.mutex);
2545 if (argc != 2 && argc != 3) {
2546 ti->error = "Invalid argument count";
2551 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2553 ti->error = "Out of memory";
2559 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
2561 ti->error = "Error opening origin device";
2562 goto bad_origin_dev;
2564 tc->origin_dev = origin_dev;
2567 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2569 ti->error = "Error opening pool device";
2572 tc->pool_dev = pool_dev;
2574 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2575 ti->error = "Invalid device id";
2580 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2582 ti->error = "Couldn't get pool mapped device";
2587 tc->pool = __pool_table_lookup(pool_md);
2589 ti->error = "Couldn't find pool object";
2591 goto bad_pool_lookup;
2593 __pool_inc(tc->pool);
2595 if (get_pool_mode(tc->pool) == PM_FAIL) {
2596 ti->error = "Couldn't open thin device, Pool is in fail mode";
2600 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
2602 ti->error = "Couldn't open thin internal device";
2606 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
2610 ti->num_flush_requests = 1;
2611 ti->flush_supported = true;
2613 /* In case the pool supports discards, pass them on. */
2614 if (tc->pool->pf.discard_enabled) {
2615 ti->discards_supported = true;
2616 ti->num_discard_requests = 1;
2617 ti->discard_zeroes_data_unsupported = true;
2618 /* Discard requests must be split on a block boundary */
2619 ti->split_discard_requests = true;
2624 mutex_unlock(&dm_thin_pool_table.mutex);
2629 __pool_dec(tc->pool);
2633 dm_put_device(ti, tc->pool_dev);
2636 dm_put_device(ti, tc->origin_dev);
2640 mutex_unlock(&dm_thin_pool_table.mutex);
2645 static int thin_map(struct dm_target *ti, struct bio *bio,
2646 union map_info *map_context)
2648 bio->bi_sector = dm_target_offset(ti, bio->bi_sector);
2650 return thin_bio_map(ti, bio, map_context);
2653 static int thin_endio(struct dm_target *ti,
2654 struct bio *bio, int err,
2655 union map_info *map_context)
2657 unsigned long flags;
2658 struct dm_thin_endio_hook *h = map_context->ptr;
2659 struct list_head work;
2660 struct dm_thin_new_mapping *m, *tmp;
2661 struct pool *pool = h->tc->pool;
2663 if (h->shared_read_entry) {
2664 INIT_LIST_HEAD(&work);
2665 dm_deferred_entry_dec(h->shared_read_entry, &work);
2667 spin_lock_irqsave(&pool->lock, flags);
2668 list_for_each_entry_safe(m, tmp, &work, list) {
2671 __maybe_add_mapping(m);
2673 spin_unlock_irqrestore(&pool->lock, flags);
2676 if (h->all_io_entry) {
2677 INIT_LIST_HEAD(&work);
2678 dm_deferred_entry_dec(h->all_io_entry, &work);
2679 if (!list_empty(&work)) {
2680 spin_lock_irqsave(&pool->lock, flags);
2681 list_for_each_entry_safe(m, tmp, &work, list)
2682 list_add(&m->list, &pool->prepared_discards);
2683 spin_unlock_irqrestore(&pool->lock, flags);
2688 mempool_free(h, pool->endio_hook_pool);
2693 static void thin_postsuspend(struct dm_target *ti)
2695 if (dm_noflush_suspending(ti))
2696 requeue_io((struct thin_c *)ti->private);
2700 * <nr mapped sectors> <highest mapped sector>
2702 static int thin_status(struct dm_target *ti, status_type_t type,
2703 unsigned status_flags, char *result, unsigned maxlen)
2707 dm_block_t mapped, highest;
2708 char buf[BDEVNAME_SIZE];
2709 struct thin_c *tc = ti->private;
2711 if (get_pool_mode(tc->pool) == PM_FAIL) {
2720 case STATUSTYPE_INFO:
2721 r = dm_thin_get_mapped_count(tc->td, &mapped);
2725 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
2729 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
2731 DMEMIT("%llu", ((highest + 1) *
2732 tc->pool->sectors_per_block) - 1);
2737 case STATUSTYPE_TABLE:
2739 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
2740 (unsigned long) tc->dev_id);
2742 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
2750 static int thin_iterate_devices(struct dm_target *ti,
2751 iterate_devices_callout_fn fn, void *data)
2754 struct thin_c *tc = ti->private;
2755 struct pool *pool = tc->pool;
2758 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2759 * we follow a more convoluted path through to the pool's target.
2762 return 0; /* nothing is bound */
2764 blocks = pool->ti->len;
2765 (void) sector_div(blocks, pool->sectors_per_block);
2767 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
2773 * A thin device always inherits its queue limits from its pool.
2775 static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
2777 struct thin_c *tc = ti->private;
2779 *limits = bdev_get_queue(tc->pool_dev->bdev)->limits;
2782 static struct target_type thin_target = {
2784 .version = {1, 5, 0},
2785 .module = THIS_MODULE,
2789 .end_io = thin_endio,
2790 .postsuspend = thin_postsuspend,
2791 .status = thin_status,
2792 .iterate_devices = thin_iterate_devices,
2793 .io_hints = thin_io_hints,
2796 /*----------------------------------------------------------------*/
2798 static int __init dm_thin_init(void)
2804 r = dm_register_target(&thin_target);
2808 r = dm_register_target(&pool_target);
2810 goto bad_pool_target;
2814 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
2815 if (!_new_mapping_cache)
2816 goto bad_new_mapping_cache;
2818 _endio_hook_cache = KMEM_CACHE(dm_thin_endio_hook, 0);
2819 if (!_endio_hook_cache)
2820 goto bad_endio_hook_cache;
2824 bad_endio_hook_cache:
2825 kmem_cache_destroy(_new_mapping_cache);
2826 bad_new_mapping_cache:
2827 dm_unregister_target(&pool_target);
2829 dm_unregister_target(&thin_target);
2834 static void dm_thin_exit(void)
2836 dm_unregister_target(&thin_target);
2837 dm_unregister_target(&pool_target);
2839 kmem_cache_destroy(_new_mapping_cache);
2840 kmem_cache_destroy(_endio_hook_cache);
2843 module_init(dm_thin_init);
2844 module_exit(dm_thin_exit);
2846 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
2847 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2848 MODULE_LICENSE("GPL");