2 * Copyright (C) 2011 Red Hat UK.
4 * This file is released under the GPL.
7 #include "dm-thin-metadata.h"
9 #include <linux/device-mapper.h>
10 #include <linux/dm-io.h>
11 #include <linux/dm-kcopyd.h>
12 #include <linux/list.h>
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
17 #define DM_MSG_PREFIX "thin"
22 #define ENDIO_HOOK_POOL_SIZE 10240
23 #define DEFERRED_SET_SIZE 64
24 #define MAPPING_POOL_SIZE 1024
25 #define PRISON_CELLS 1024
28 * The block size of the device holding pool data must be
29 * between 64KB and 1GB.
31 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
32 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
35 * The metadata device is currently limited in size. The limitation is
36 * checked lower down in dm-space-map-metadata, but we also check it here
37 * so we can fail early.
39 * We have one block of index, which can hold 255 index entries. Each
40 * index entry contains allocation info about 16k metadata blocks.
42 #define METADATA_DEV_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT)))
45 * Device id is restricted to 24 bits.
47 #define MAX_DEV_ID ((1 << 24) - 1)
50 * How do we handle breaking sharing of data blocks?
51 * =================================================
53 * We use a standard copy-on-write btree to store the mappings for the
54 * devices (note I'm talking about copy-on-write of the metadata here, not
55 * the data). When you take an internal snapshot you clone the root node
56 * of the origin btree. After this there is no concept of an origin or a
57 * snapshot. They are just two device trees that happen to point to the
60 * When we get a write in we decide if it's to a shared data block using
61 * some timestamp magic. If it is, we have to break sharing.
63 * Let's say we write to a shared block in what was the origin. The
66 * i) plug io further to this physical block. (see bio_prison code).
68 * ii) quiesce any read io to that shared data block. Obviously
69 * including all devices that share this block. (see deferred_set code)
71 * iii) copy the data block to a newly allocate block. This step can be
72 * missed out if the io covers the block. (schedule_copy).
74 * iv) insert the new mapping into the origin's btree
75 * (process_prepared_mappings). This act of inserting breaks some
76 * sharing of btree nodes between the two devices. Breaking sharing only
77 * effects the btree of that specific device. Btrees for the other
78 * devices that share the block never change. The btree for the origin
79 * device as it was after the last commit is untouched, ie. we're using
80 * persistent data structures in the functional programming sense.
82 * v) unplug io to this physical block, including the io that triggered
83 * the breaking of sharing.
85 * Steps (ii) and (iii) occur in parallel.
87 * The metadata _doesn't_ need to be committed before the io continues. We
88 * get away with this because the io is always written to a _new_ block.
89 * If there's a crash, then:
91 * - The origin mapping will point to the old origin block (the shared
92 * one). This will contain the data as it was before the io that triggered
93 * the breaking of sharing came in.
95 * - The snap mapping still points to the old block. As it would after
98 * The downside of this scheme is the timestamp magic isn't perfect, and
99 * will continue to think that data block in the snapshot device is shared
100 * even after the write to the origin has broken sharing. I suspect data
101 * blocks will typically be shared by many different devices, so we're
102 * breaking sharing n + 1 times, rather than n, where n is the number of
103 * devices that reference this data block. At the moment I think the
104 * benefits far, far outweigh the disadvantages.
107 /*----------------------------------------------------------------*/
110 * Sometimes we can't deal with a bio straight away. We put them in prison
111 * where they can't cause any mischief. Bios are put in a cell identified
112 * by a key, multiple bios can be in the same cell. When the cell is
113 * subsequently unlocked the bios become available.
124 struct hlist_node list;
125 struct bio_prison *prison;
128 struct bio_list bios;
133 mempool_t *cell_pool;
137 struct hlist_head *cells;
140 static uint32_t calc_nr_buckets(unsigned nr_cells)
145 nr_cells = min(nr_cells, 8192u);
154 * @nr_cells should be the number of cells you want in use _concurrently_.
155 * Don't confuse it with the number of distinct keys.
157 static struct bio_prison *prison_create(unsigned nr_cells)
160 uint32_t nr_buckets = calc_nr_buckets(nr_cells);
161 size_t len = sizeof(struct bio_prison) +
162 (sizeof(struct hlist_head) * nr_buckets);
163 struct bio_prison *prison = kmalloc(len, GFP_KERNEL);
168 spin_lock_init(&prison->lock);
169 prison->cell_pool = mempool_create_kmalloc_pool(nr_cells,
170 sizeof(struct cell));
171 if (!prison->cell_pool) {
176 prison->nr_buckets = nr_buckets;
177 prison->hash_mask = nr_buckets - 1;
178 prison->cells = (struct hlist_head *) (prison + 1);
179 for (i = 0; i < nr_buckets; i++)
180 INIT_HLIST_HEAD(prison->cells + i);
185 static void prison_destroy(struct bio_prison *prison)
187 mempool_destroy(prison->cell_pool);
191 static uint32_t hash_key(struct bio_prison *prison, struct cell_key *key)
193 const unsigned long BIG_PRIME = 4294967291UL;
194 uint64_t hash = key->block * BIG_PRIME;
196 return (uint32_t) (hash & prison->hash_mask);
199 static int keys_equal(struct cell_key *lhs, struct cell_key *rhs)
201 return (lhs->virtual == rhs->virtual) &&
202 (lhs->dev == rhs->dev) &&
203 (lhs->block == rhs->block);
206 static struct cell *__search_bucket(struct hlist_head *bucket,
207 struct cell_key *key)
210 struct hlist_node *tmp;
212 hlist_for_each_entry(cell, tmp, bucket, list)
213 if (keys_equal(&cell->key, key))
220 * This may block if a new cell needs allocating. You must ensure that
221 * cells will be unlocked even if the calling thread is blocked.
223 * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
225 static int bio_detain(struct bio_prison *prison, struct cell_key *key,
226 struct bio *inmate, struct cell **ref)
230 uint32_t hash = hash_key(prison, key);
231 struct cell *cell, *cell2;
233 BUG_ON(hash > prison->nr_buckets);
235 spin_lock_irqsave(&prison->lock, flags);
237 cell = __search_bucket(prison->cells + hash, key);
239 bio_list_add(&cell->bios, inmate);
244 * Allocate a new cell
246 spin_unlock_irqrestore(&prison->lock, flags);
247 cell2 = mempool_alloc(prison->cell_pool, GFP_NOIO);
248 spin_lock_irqsave(&prison->lock, flags);
251 * We've been unlocked, so we have to double check that
252 * nobody else has inserted this cell in the meantime.
254 cell = __search_bucket(prison->cells + hash, key);
256 mempool_free(cell2, prison->cell_pool);
257 bio_list_add(&cell->bios, inmate);
266 cell->prison = prison;
267 memcpy(&cell->key, key, sizeof(cell->key));
268 cell->holder = inmate;
269 bio_list_init(&cell->bios);
270 hlist_add_head(&cell->list, prison->cells + hash);
275 spin_unlock_irqrestore(&prison->lock, flags);
283 * @inmates must have been initialised prior to this call
285 static void __cell_release(struct cell *cell, struct bio_list *inmates)
287 struct bio_prison *prison = cell->prison;
289 hlist_del(&cell->list);
291 bio_list_add(inmates, cell->holder);
292 bio_list_merge(inmates, &cell->bios);
294 mempool_free(cell, prison->cell_pool);
297 static void cell_release(struct cell *cell, struct bio_list *bios)
300 struct bio_prison *prison = cell->prison;
302 spin_lock_irqsave(&prison->lock, flags);
303 __cell_release(cell, bios);
304 spin_unlock_irqrestore(&prison->lock, flags);
308 * There are a couple of places where we put a bio into a cell briefly
309 * before taking it out again. In these situations we know that no other
310 * bio may be in the cell. This function releases the cell, and also does
313 static void __cell_release_singleton(struct cell *cell, struct bio *bio)
315 hlist_del(&cell->list);
316 BUG_ON(cell->holder != bio);
317 BUG_ON(!bio_list_empty(&cell->bios));
320 static void cell_release_singleton(struct cell *cell, struct bio *bio)
323 struct bio_prison *prison = cell->prison;
325 spin_lock_irqsave(&prison->lock, flags);
326 __cell_release_singleton(cell, bio);
327 spin_unlock_irqrestore(&prison->lock, flags);
331 * Sometimes we don't want the holder, just the additional bios.
333 static void __cell_release_no_holder(struct cell *cell, struct bio_list *inmates)
335 struct bio_prison *prison = cell->prison;
337 hlist_del(&cell->list);
338 bio_list_merge(inmates, &cell->bios);
340 mempool_free(cell, prison->cell_pool);
343 static void cell_release_no_holder(struct cell *cell, struct bio_list *inmates)
346 struct bio_prison *prison = cell->prison;
348 spin_lock_irqsave(&prison->lock, flags);
349 __cell_release_no_holder(cell, inmates);
350 spin_unlock_irqrestore(&prison->lock, flags);
353 static void cell_error(struct cell *cell)
355 struct bio_prison *prison = cell->prison;
356 struct bio_list bios;
360 bio_list_init(&bios);
362 spin_lock_irqsave(&prison->lock, flags);
363 __cell_release(cell, &bios);
364 spin_unlock_irqrestore(&prison->lock, flags);
366 while ((bio = bio_list_pop(&bios)))
370 /*----------------------------------------------------------------*/
373 * We use the deferred set to keep track of pending reads to shared blocks.
374 * We do this to ensure the new mapping caused by a write isn't performed
375 * until these prior reads have completed. Otherwise the insertion of the
376 * new mapping could free the old block that the read bios are mapped to.
380 struct deferred_entry {
381 struct deferred_set *ds;
383 struct list_head work_items;
386 struct deferred_set {
388 unsigned current_entry;
390 struct deferred_entry entries[DEFERRED_SET_SIZE];
393 static void ds_init(struct deferred_set *ds)
397 spin_lock_init(&ds->lock);
398 ds->current_entry = 0;
400 for (i = 0; i < DEFERRED_SET_SIZE; i++) {
401 ds->entries[i].ds = ds;
402 ds->entries[i].count = 0;
403 INIT_LIST_HEAD(&ds->entries[i].work_items);
407 static struct deferred_entry *ds_inc(struct deferred_set *ds)
410 struct deferred_entry *entry;
412 spin_lock_irqsave(&ds->lock, flags);
413 entry = ds->entries + ds->current_entry;
415 spin_unlock_irqrestore(&ds->lock, flags);
420 static unsigned ds_next(unsigned index)
422 return (index + 1) % DEFERRED_SET_SIZE;
425 static void __sweep(struct deferred_set *ds, struct list_head *head)
427 while ((ds->sweeper != ds->current_entry) &&
428 !ds->entries[ds->sweeper].count) {
429 list_splice_init(&ds->entries[ds->sweeper].work_items, head);
430 ds->sweeper = ds_next(ds->sweeper);
433 if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count)
434 list_splice_init(&ds->entries[ds->sweeper].work_items, head);
437 static void ds_dec(struct deferred_entry *entry, struct list_head *head)
441 spin_lock_irqsave(&entry->ds->lock, flags);
442 BUG_ON(!entry->count);
444 __sweep(entry->ds, head);
445 spin_unlock_irqrestore(&entry->ds->lock, flags);
449 * Returns 1 if deferred or 0 if no pending items to delay job.
451 static int ds_add_work(struct deferred_set *ds, struct list_head *work)
457 spin_lock_irqsave(&ds->lock, flags);
458 if ((ds->sweeper == ds->current_entry) &&
459 !ds->entries[ds->current_entry].count)
462 list_add(work, &ds->entries[ds->current_entry].work_items);
463 next_entry = ds_next(ds->current_entry);
464 if (!ds->entries[next_entry].count)
465 ds->current_entry = next_entry;
467 spin_unlock_irqrestore(&ds->lock, flags);
472 /*----------------------------------------------------------------*/
477 static void build_data_key(struct dm_thin_device *td,
478 dm_block_t b, struct cell_key *key)
481 key->dev = dm_thin_dev_id(td);
485 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
486 struct cell_key *key)
489 key->dev = dm_thin_dev_id(td);
493 /*----------------------------------------------------------------*/
496 * A pool device ties together a metadata device and a data device. It
497 * also provides the interface for creating and destroying internal
502 struct list_head list;
503 struct dm_target *ti; /* Only set if a pool target is bound */
505 struct mapped_device *pool_md;
506 struct block_device *md_dev;
507 struct dm_pool_metadata *pmd;
509 uint32_t sectors_per_block;
510 unsigned block_shift;
511 dm_block_t offset_mask;
512 dm_block_t low_water_blocks;
514 unsigned zero_new_blocks:1;
515 unsigned low_water_triggered:1; /* A dm event has been sent */
516 unsigned no_free_space:1; /* A -ENOSPC warning has been issued */
518 struct bio_prison *prison;
519 struct dm_kcopyd_client *copier;
521 struct workqueue_struct *wq;
522 struct work_struct worker;
527 struct bio_list deferred_bios;
528 struct bio_list deferred_flush_bios;
529 struct list_head prepared_mappings;
531 struct bio_list retry_on_resume_list;
533 struct deferred_set ds; /* FIXME: move to thin_c */
535 struct new_mapping *next_mapping;
536 mempool_t *mapping_pool;
537 mempool_t *endio_hook_pool;
541 * Target context for a pool.
544 struct dm_target *ti;
546 struct dm_dev *data_dev;
547 struct dm_dev *metadata_dev;
548 struct dm_target_callbacks callbacks;
550 dm_block_t low_water_blocks;
551 unsigned zero_new_blocks:1;
555 * Target context for a thin.
558 struct dm_dev *pool_dev;
562 struct dm_thin_device *td;
565 /*----------------------------------------------------------------*/
568 * A global list of pools that uses a struct mapped_device as a key.
570 static struct dm_thin_pool_table {
572 struct list_head pools;
573 } dm_thin_pool_table;
575 static void pool_table_init(void)
577 mutex_init(&dm_thin_pool_table.mutex);
578 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
581 static void __pool_table_insert(struct pool *pool)
583 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
584 list_add(&pool->list, &dm_thin_pool_table.pools);
587 static void __pool_table_remove(struct pool *pool)
589 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
590 list_del(&pool->list);
593 static struct pool *__pool_table_lookup(struct mapped_device *md)
595 struct pool *pool = NULL, *tmp;
597 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
599 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
600 if (tmp->pool_md == md) {
609 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
611 struct pool *pool = NULL, *tmp;
613 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
615 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
616 if (tmp->md_dev == md_dev) {
625 /*----------------------------------------------------------------*/
627 static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
630 struct bio_list bios;
632 bio_list_init(&bios);
633 bio_list_merge(&bios, master);
634 bio_list_init(master);
636 while ((bio = bio_list_pop(&bios))) {
637 if (dm_get_mapinfo(bio)->ptr == tc)
638 bio_endio(bio, DM_ENDIO_REQUEUE);
640 bio_list_add(master, bio);
644 static void requeue_io(struct thin_c *tc)
646 struct pool *pool = tc->pool;
649 spin_lock_irqsave(&pool->lock, flags);
650 __requeue_bio_list(tc, &pool->deferred_bios);
651 __requeue_bio_list(tc, &pool->retry_on_resume_list);
652 spin_unlock_irqrestore(&pool->lock, flags);
656 * This section of code contains the logic for processing a thin device's IO.
657 * Much of the code depends on pool object resources (lists, workqueues, etc)
658 * but most is exclusively called from the thin target rather than the thin-pool
662 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
664 return bio->bi_sector >> tc->pool->block_shift;
667 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
669 struct pool *pool = tc->pool;
671 bio->bi_bdev = tc->pool_dev->bdev;
672 bio->bi_sector = (block << pool->block_shift) +
673 (bio->bi_sector & pool->offset_mask);
676 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
679 struct pool *pool = tc->pool;
682 remap(tc, bio, block);
685 * Batch together any FUA/FLUSH bios we find and then issue
686 * a single commit for them in process_deferred_bios().
688 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
689 spin_lock_irqsave(&pool->lock, flags);
690 bio_list_add(&pool->deferred_flush_bios, bio);
691 spin_unlock_irqrestore(&pool->lock, flags);
693 generic_make_request(bio);
697 * wake_worker() is used when new work is queued and when pool_resume is
698 * ready to continue deferred IO processing.
700 static void wake_worker(struct pool *pool)
702 queue_work(pool->wq, &pool->worker);
705 /*----------------------------------------------------------------*/
708 * Bio endio functions.
712 bio_end_io_t *saved_bi_end_io;
713 struct deferred_entry *entry;
717 struct list_head list;
722 dm_block_t virt_block;
723 dm_block_t data_block;
728 * If the bio covers the whole area of a block then we can avoid
729 * zeroing or copying. Instead this bio is hooked. The bio will
730 * still be in the cell, so care has to be taken to avoid issuing
734 bio_end_io_t *saved_bi_end_io;
737 static void __maybe_add_mapping(struct new_mapping *m)
739 struct pool *pool = m->tc->pool;
741 if (list_empty(&m->list) && m->prepared) {
742 list_add(&m->list, &pool->prepared_mappings);
747 static void copy_complete(int read_err, unsigned long write_err, void *context)
750 struct new_mapping *m = context;
751 struct pool *pool = m->tc->pool;
753 m->err = read_err || write_err ? -EIO : 0;
755 spin_lock_irqsave(&pool->lock, flags);
757 __maybe_add_mapping(m);
758 spin_unlock_irqrestore(&pool->lock, flags);
761 static void overwrite_endio(struct bio *bio, int err)
764 struct new_mapping *m = dm_get_mapinfo(bio)->ptr;
765 struct pool *pool = m->tc->pool;
769 spin_lock_irqsave(&pool->lock, flags);
771 __maybe_add_mapping(m);
772 spin_unlock_irqrestore(&pool->lock, flags);
775 static void shared_read_endio(struct bio *bio, int err)
777 struct list_head mappings;
778 struct new_mapping *m, *tmp;
779 struct endio_hook *h = dm_get_mapinfo(bio)->ptr;
781 struct pool *pool = h->tc->pool;
783 bio->bi_end_io = h->saved_bi_end_io;
786 INIT_LIST_HEAD(&mappings);
787 ds_dec(h->entry, &mappings);
789 spin_lock_irqsave(&pool->lock, flags);
790 list_for_each_entry_safe(m, tmp, &mappings, list) {
792 INIT_LIST_HEAD(&m->list);
793 __maybe_add_mapping(m);
795 spin_unlock_irqrestore(&pool->lock, flags);
797 mempool_free(h, pool->endio_hook_pool);
800 /*----------------------------------------------------------------*/
807 * Prepared mapping jobs.
811 * This sends the bios in the cell back to the deferred_bios list.
813 static void cell_defer(struct thin_c *tc, struct cell *cell,
814 dm_block_t data_block)
816 struct pool *pool = tc->pool;
819 spin_lock_irqsave(&pool->lock, flags);
820 cell_release(cell, &pool->deferred_bios);
821 spin_unlock_irqrestore(&tc->pool->lock, flags);
827 * Same as cell_defer above, except it omits one particular detainee,
828 * a write bio that covers the block and has already been processed.
830 static void cell_defer_except(struct thin_c *tc, struct cell *cell)
832 struct bio_list bios;
833 struct pool *pool = tc->pool;
836 bio_list_init(&bios);
838 spin_lock_irqsave(&pool->lock, flags);
839 cell_release_no_holder(cell, &pool->deferred_bios);
840 spin_unlock_irqrestore(&pool->lock, flags);
845 static void process_prepared_mapping(struct new_mapping *m)
847 struct thin_c *tc = m->tc;
853 bio->bi_end_io = m->saved_bi_end_io;
861 * Commit the prepared block into the mapping btree.
862 * Any I/O for this block arriving after this point will get
863 * remapped to it directly.
865 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
867 DMERR("dm_thin_insert_block() failed");
873 * Release any bios held while the block was being provisioned.
874 * If we are processing a write bio that completely covers the block,
875 * we already processed it so can ignore it now when processing
876 * the bios in the cell.
879 cell_defer_except(tc, m->cell);
882 cell_defer(tc, m->cell, m->data_block);
885 mempool_free(m, tc->pool->mapping_pool);
888 static void process_prepared_mappings(struct pool *pool)
891 struct list_head maps;
892 struct new_mapping *m, *tmp;
894 INIT_LIST_HEAD(&maps);
895 spin_lock_irqsave(&pool->lock, flags);
896 list_splice_init(&pool->prepared_mappings, &maps);
897 spin_unlock_irqrestore(&pool->lock, flags);
899 list_for_each_entry_safe(m, tmp, &maps, list)
900 process_prepared_mapping(m);
906 static int io_overwrites_block(struct pool *pool, struct bio *bio)
908 return ((bio_data_dir(bio) == WRITE) &&
909 !(bio->bi_sector & pool->offset_mask)) &&
910 (bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT));
913 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
916 *save = bio->bi_end_io;
920 static int ensure_next_mapping(struct pool *pool)
922 if (pool->next_mapping)
925 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
927 return pool->next_mapping ? 0 : -ENOMEM;
930 static struct new_mapping *get_next_mapping(struct pool *pool)
932 struct new_mapping *r = pool->next_mapping;
934 BUG_ON(!pool->next_mapping);
936 pool->next_mapping = NULL;
941 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
942 dm_block_t data_origin, dm_block_t data_dest,
943 struct cell *cell, struct bio *bio)
946 struct pool *pool = tc->pool;
947 struct new_mapping *m = get_next_mapping(pool);
949 INIT_LIST_HEAD(&m->list);
952 m->virt_block = virt_block;
953 m->data_block = data_dest;
958 ds_add_work(&pool->ds, &m->list);
961 * IO to pool_dev remaps to the pool target's data_dev.
963 * If the whole block of data is being overwritten, we can issue the
964 * bio immediately. Otherwise we use kcopyd to clone the data first.
966 if (io_overwrites_block(pool, bio)) {
968 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
969 dm_get_mapinfo(bio)->ptr = m;
970 remap_and_issue(tc, bio, data_dest);
972 struct dm_io_region from, to;
974 from.bdev = tc->pool_dev->bdev;
975 from.sector = data_origin * pool->sectors_per_block;
976 from.count = pool->sectors_per_block;
978 to.bdev = tc->pool_dev->bdev;
979 to.sector = data_dest * pool->sectors_per_block;
980 to.count = pool->sectors_per_block;
982 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
983 0, copy_complete, m);
985 mempool_free(m, pool->mapping_pool);
986 DMERR("dm_kcopyd_copy() failed");
992 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
993 dm_block_t data_block, struct cell *cell,
996 struct pool *pool = tc->pool;
997 struct new_mapping *m = get_next_mapping(pool);
999 INIT_LIST_HEAD(&m->list);
1002 m->virt_block = virt_block;
1003 m->data_block = data_block;
1009 * If the whole block of data is being overwritten or we are not
1010 * zeroing pre-existing data, we can issue the bio immediately.
1011 * Otherwise we use kcopyd to zero the data first.
1013 if (!pool->zero_new_blocks)
1014 process_prepared_mapping(m);
1016 else if (io_overwrites_block(pool, bio)) {
1018 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
1019 dm_get_mapinfo(bio)->ptr = m;
1020 remap_and_issue(tc, bio, data_block);
1024 struct dm_io_region to;
1026 to.bdev = tc->pool_dev->bdev;
1027 to.sector = data_block * pool->sectors_per_block;
1028 to.count = pool->sectors_per_block;
1030 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
1032 mempool_free(m, pool->mapping_pool);
1033 DMERR("dm_kcopyd_zero() failed");
1039 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1042 dm_block_t free_blocks;
1043 unsigned long flags;
1044 struct pool *pool = tc->pool;
1046 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1050 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1051 DMWARN("%s: reached low water mark, sending event.",
1052 dm_device_name(pool->pool_md));
1053 spin_lock_irqsave(&pool->lock, flags);
1054 pool->low_water_triggered = 1;
1055 spin_unlock_irqrestore(&pool->lock, flags);
1056 dm_table_event(pool->ti->table);
1060 if (pool->no_free_space)
1064 * Try to commit to see if that will free up some
1067 r = dm_pool_commit_metadata(pool->pmd);
1069 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1074 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1079 * If we still have no space we set a flag to avoid
1080 * doing all this checking and return -ENOSPC.
1083 DMWARN("%s: no free space available.",
1084 dm_device_name(pool->pool_md));
1085 spin_lock_irqsave(&pool->lock, flags);
1086 pool->no_free_space = 1;
1087 spin_unlock_irqrestore(&pool->lock, flags);
1093 r = dm_pool_alloc_data_block(pool->pmd, result);
1101 * If we have run out of space, queue bios until the device is
1102 * resumed, presumably after having been reloaded with more space.
1104 static void retry_on_resume(struct bio *bio)
1106 struct thin_c *tc = dm_get_mapinfo(bio)->ptr;
1107 struct pool *pool = tc->pool;
1108 unsigned long flags;
1110 spin_lock_irqsave(&pool->lock, flags);
1111 bio_list_add(&pool->retry_on_resume_list, bio);
1112 spin_unlock_irqrestore(&pool->lock, flags);
1115 static void no_space(struct cell *cell)
1118 struct bio_list bios;
1120 bio_list_init(&bios);
1121 cell_release(cell, &bios);
1123 while ((bio = bio_list_pop(&bios)))
1124 retry_on_resume(bio);
1127 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1128 struct cell_key *key,
1129 struct dm_thin_lookup_result *lookup_result,
1133 dm_block_t data_block;
1135 r = alloc_data_block(tc, &data_block);
1138 schedule_copy(tc, block, lookup_result->block,
1139 data_block, cell, bio);
1147 DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
1153 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1155 struct dm_thin_lookup_result *lookup_result)
1158 struct pool *pool = tc->pool;
1159 struct cell_key key;
1162 * If cell is already occupied, then sharing is already in the process
1163 * of being broken so we have nothing further to do here.
1165 build_data_key(tc->td, lookup_result->block, &key);
1166 if (bio_detain(pool->prison, &key, bio, &cell))
1169 if (bio_data_dir(bio) == WRITE)
1170 break_sharing(tc, bio, block, &key, lookup_result, cell);
1172 struct endio_hook *h;
1173 h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO);
1176 h->entry = ds_inc(&pool->ds);
1177 save_and_set_endio(bio, &h->saved_bi_end_io, shared_read_endio);
1178 dm_get_mapinfo(bio)->ptr = h;
1180 cell_release_singleton(cell, bio);
1181 remap_and_issue(tc, bio, lookup_result->block);
1185 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1189 dm_block_t data_block;
1192 * Remap empty bios (flushes) immediately, without provisioning.
1194 if (!bio->bi_size) {
1195 cell_release_singleton(cell, bio);
1196 remap_and_issue(tc, bio, 0);
1201 * Fill read bios with zeroes and complete them immediately.
1203 if (bio_data_dir(bio) == READ) {
1205 cell_release_singleton(cell, bio);
1210 r = alloc_data_block(tc, &data_block);
1213 schedule_zero(tc, block, data_block, cell, bio);
1221 DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
1227 static void process_bio(struct thin_c *tc, struct bio *bio)
1230 dm_block_t block = get_bio_block(tc, bio);
1232 struct cell_key key;
1233 struct dm_thin_lookup_result lookup_result;
1236 * If cell is already occupied, then the block is already
1237 * being provisioned so we have nothing further to do here.
1239 build_virtual_key(tc->td, block, &key);
1240 if (bio_detain(tc->pool->prison, &key, bio, &cell))
1243 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1247 * We can release this cell now. This thread is the only
1248 * one that puts bios into a cell, and we know there were
1249 * no preceding bios.
1252 * TODO: this will probably have to change when discard goes
1255 cell_release_singleton(cell, bio);
1257 if (lookup_result.shared)
1258 process_shared_bio(tc, bio, block, &lookup_result);
1260 remap_and_issue(tc, bio, lookup_result.block);
1264 provision_block(tc, bio, block, cell);
1268 DMERR("dm_thin_find_block() failed, error = %d", r);
1274 static void process_deferred_bios(struct pool *pool)
1276 unsigned long flags;
1278 struct bio_list bios;
1281 bio_list_init(&bios);
1283 spin_lock_irqsave(&pool->lock, flags);
1284 bio_list_merge(&bios, &pool->deferred_bios);
1285 bio_list_init(&pool->deferred_bios);
1286 spin_unlock_irqrestore(&pool->lock, flags);
1288 while ((bio = bio_list_pop(&bios))) {
1289 struct thin_c *tc = dm_get_mapinfo(bio)->ptr;
1291 * If we've got no free new_mapping structs, and processing
1292 * this bio might require one, we pause until there are some
1293 * prepared mappings to process.
1295 if (ensure_next_mapping(pool)) {
1296 spin_lock_irqsave(&pool->lock, flags);
1297 bio_list_merge(&pool->deferred_bios, &bios);
1298 spin_unlock_irqrestore(&pool->lock, flags);
1302 process_bio(tc, bio);
1306 * If there are any deferred flush bios, we must commit
1307 * the metadata before issuing them.
1309 bio_list_init(&bios);
1310 spin_lock_irqsave(&pool->lock, flags);
1311 bio_list_merge(&bios, &pool->deferred_flush_bios);
1312 bio_list_init(&pool->deferred_flush_bios);
1313 spin_unlock_irqrestore(&pool->lock, flags);
1315 if (bio_list_empty(&bios))
1318 r = dm_pool_commit_metadata(pool->pmd);
1320 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1322 while ((bio = bio_list_pop(&bios)))
1327 while ((bio = bio_list_pop(&bios)))
1328 generic_make_request(bio);
1331 static void do_worker(struct work_struct *ws)
1333 struct pool *pool = container_of(ws, struct pool, worker);
1335 process_prepared_mappings(pool);
1336 process_deferred_bios(pool);
1339 /*----------------------------------------------------------------*/
1342 * Mapping functions.
1346 * Called only while mapping a thin bio to hand it over to the workqueue.
1348 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1350 unsigned long flags;
1351 struct pool *pool = tc->pool;
1353 spin_lock_irqsave(&pool->lock, flags);
1354 bio_list_add(&pool->deferred_bios, bio);
1355 spin_unlock_irqrestore(&pool->lock, flags);
1361 * Non-blocking function called from the thin target's map function.
1363 static int thin_bio_map(struct dm_target *ti, struct bio *bio,
1364 union map_info *map_context)
1367 struct thin_c *tc = ti->private;
1368 dm_block_t block = get_bio_block(tc, bio);
1369 struct dm_thin_device *td = tc->td;
1370 struct dm_thin_lookup_result result;
1373 * Save the thin context for easy access from the deferred bio later.
1375 map_context->ptr = tc;
1377 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
1378 thin_defer_bio(tc, bio);
1379 return DM_MAPIO_SUBMITTED;
1382 r = dm_thin_find_block(td, block, 0, &result);
1385 * Note that we defer readahead too.
1389 if (unlikely(result.shared)) {
1391 * We have a race condition here between the
1392 * result.shared value returned by the lookup and
1393 * snapshot creation, which may cause new
1396 * To avoid this always quiesce the origin before
1397 * taking the snap. You want to do this anyway to
1398 * ensure a consistent application view
1401 * More distant ancestors are irrelevant. The
1402 * shared flag will be set in their case.
1404 thin_defer_bio(tc, bio);
1405 r = DM_MAPIO_SUBMITTED;
1407 remap(tc, bio, result.block);
1408 r = DM_MAPIO_REMAPPED;
1414 * In future, the failed dm_thin_find_block above could
1415 * provide the hint to load the metadata into cache.
1418 thin_defer_bio(tc, bio);
1419 r = DM_MAPIO_SUBMITTED;
1426 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1429 unsigned long flags;
1430 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1432 spin_lock_irqsave(&pt->pool->lock, flags);
1433 r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1434 spin_unlock_irqrestore(&pt->pool->lock, flags);
1437 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1438 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1444 static void __requeue_bios(struct pool *pool)
1446 bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1447 bio_list_init(&pool->retry_on_resume_list);
1450 /*----------------------------------------------------------------
1451 * Binding of control targets to a pool object
1452 *--------------------------------------------------------------*/
1453 static int bind_control_target(struct pool *pool, struct dm_target *ti)
1455 struct pool_c *pt = ti->private;
1458 pool->low_water_blocks = pt->low_water_blocks;
1459 pool->zero_new_blocks = pt->zero_new_blocks;
1464 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1470 /*----------------------------------------------------------------
1472 *--------------------------------------------------------------*/
1473 static void __pool_destroy(struct pool *pool)
1475 __pool_table_remove(pool);
1477 if (dm_pool_metadata_close(pool->pmd) < 0)
1478 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1480 prison_destroy(pool->prison);
1481 dm_kcopyd_client_destroy(pool->copier);
1484 destroy_workqueue(pool->wq);
1486 if (pool->next_mapping)
1487 mempool_free(pool->next_mapping, pool->mapping_pool);
1488 mempool_destroy(pool->mapping_pool);
1489 mempool_destroy(pool->endio_hook_pool);
1493 static struct pool *pool_create(struct mapped_device *pool_md,
1494 struct block_device *metadata_dev,
1495 unsigned long block_size, char **error)
1500 struct dm_pool_metadata *pmd;
1502 pmd = dm_pool_metadata_open(metadata_dev, block_size);
1504 *error = "Error creating metadata object";
1505 return (struct pool *)pmd;
1508 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1510 *error = "Error allocating memory for pool";
1511 err_p = ERR_PTR(-ENOMEM);
1516 pool->sectors_per_block = block_size;
1517 pool->block_shift = ffs(block_size) - 1;
1518 pool->offset_mask = block_size - 1;
1519 pool->low_water_blocks = 0;
1520 pool->zero_new_blocks = 1;
1521 pool->prison = prison_create(PRISON_CELLS);
1522 if (!pool->prison) {
1523 *error = "Error creating pool's bio prison";
1524 err_p = ERR_PTR(-ENOMEM);
1528 pool->copier = dm_kcopyd_client_create();
1529 if (IS_ERR(pool->copier)) {
1530 r = PTR_ERR(pool->copier);
1531 *error = "Error creating pool's kcopyd client";
1533 goto bad_kcopyd_client;
1537 * Create singlethreaded workqueue that will service all devices
1538 * that use this metadata.
1540 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1542 *error = "Error creating pool's workqueue";
1543 err_p = ERR_PTR(-ENOMEM);
1547 INIT_WORK(&pool->worker, do_worker);
1548 spin_lock_init(&pool->lock);
1549 bio_list_init(&pool->deferred_bios);
1550 bio_list_init(&pool->deferred_flush_bios);
1551 INIT_LIST_HEAD(&pool->prepared_mappings);
1552 pool->low_water_triggered = 0;
1553 pool->no_free_space = 0;
1554 bio_list_init(&pool->retry_on_resume_list);
1557 pool->next_mapping = NULL;
1558 pool->mapping_pool =
1559 mempool_create_kmalloc_pool(MAPPING_POOL_SIZE, sizeof(struct new_mapping));
1560 if (!pool->mapping_pool) {
1561 *error = "Error creating pool's mapping mempool";
1562 err_p = ERR_PTR(-ENOMEM);
1563 goto bad_mapping_pool;
1566 pool->endio_hook_pool =
1567 mempool_create_kmalloc_pool(ENDIO_HOOK_POOL_SIZE, sizeof(struct endio_hook));
1568 if (!pool->endio_hook_pool) {
1569 *error = "Error creating pool's endio_hook mempool";
1570 err_p = ERR_PTR(-ENOMEM);
1571 goto bad_endio_hook_pool;
1573 pool->ref_count = 1;
1574 pool->pool_md = pool_md;
1575 pool->md_dev = metadata_dev;
1576 __pool_table_insert(pool);
1580 bad_endio_hook_pool:
1581 mempool_destroy(pool->mapping_pool);
1583 destroy_workqueue(pool->wq);
1585 dm_kcopyd_client_destroy(pool->copier);
1587 prison_destroy(pool->prison);
1591 if (dm_pool_metadata_close(pmd))
1592 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1597 static void __pool_inc(struct pool *pool)
1599 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1603 static void __pool_dec(struct pool *pool)
1605 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1606 BUG_ON(!pool->ref_count);
1607 if (!--pool->ref_count)
1608 __pool_destroy(pool);
1611 static struct pool *__pool_find(struct mapped_device *pool_md,
1612 struct block_device *metadata_dev,
1613 unsigned long block_size, char **error)
1615 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1618 if (pool->pool_md != pool_md)
1619 return ERR_PTR(-EBUSY);
1623 pool = __pool_table_lookup(pool_md);
1625 if (pool->md_dev != metadata_dev)
1626 return ERR_PTR(-EINVAL);
1630 pool = pool_create(pool_md, metadata_dev, block_size, error);
1636 /*----------------------------------------------------------------
1637 * Pool target methods
1638 *--------------------------------------------------------------*/
1639 static void pool_dtr(struct dm_target *ti)
1641 struct pool_c *pt = ti->private;
1643 mutex_lock(&dm_thin_pool_table.mutex);
1645 unbind_control_target(pt->pool, ti);
1646 __pool_dec(pt->pool);
1647 dm_put_device(ti, pt->metadata_dev);
1648 dm_put_device(ti, pt->data_dev);
1651 mutex_unlock(&dm_thin_pool_table.mutex);
1654 struct pool_features {
1655 unsigned zero_new_blocks:1;
1658 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
1659 struct dm_target *ti)
1663 const char *arg_name;
1665 static struct dm_arg _args[] = {
1666 {0, 1, "Invalid number of pool feature arguments"},
1670 * No feature arguments supplied.
1675 r = dm_read_arg_group(_args, as, &argc, &ti->error);
1679 while (argc && !r) {
1680 arg_name = dm_shift_arg(as);
1683 if (!strcasecmp(arg_name, "skip_block_zeroing")) {
1684 pf->zero_new_blocks = 0;
1688 ti->error = "Unrecognised pool feature requested";
1696 * thin-pool <metadata dev> <data dev>
1697 * <data block size (sectors)>
1698 * <low water mark (blocks)>
1699 * [<#feature args> [<arg>]*]
1701 * Optional feature arguments are:
1702 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1704 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
1709 struct pool_features pf;
1710 struct dm_arg_set as;
1711 struct dm_dev *data_dev;
1712 unsigned long block_size;
1713 dm_block_t low_water_blocks;
1714 struct dm_dev *metadata_dev;
1715 sector_t metadata_dev_size;
1718 * FIXME Remove validation from scope of lock.
1720 mutex_lock(&dm_thin_pool_table.mutex);
1723 ti->error = "Invalid argument count";
1730 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev);
1732 ti->error = "Error opening metadata block device";
1736 metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT;
1737 if (metadata_dev_size > METADATA_DEV_MAX_SECTORS) {
1738 ti->error = "Metadata device is too large";
1743 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
1745 ti->error = "Error getting data device";
1749 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
1750 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
1751 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
1752 !is_power_of_2(block_size)) {
1753 ti->error = "Invalid block size";
1758 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
1759 ti->error = "Invalid low water mark";
1765 * Set default pool features.
1767 memset(&pf, 0, sizeof(pf));
1768 pf.zero_new_blocks = 1;
1770 dm_consume_args(&as, 4);
1771 r = parse_pool_features(&as, &pf, ti);
1775 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
1781 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
1782 block_size, &ti->error);
1790 pt->metadata_dev = metadata_dev;
1791 pt->data_dev = data_dev;
1792 pt->low_water_blocks = low_water_blocks;
1793 pt->zero_new_blocks = pf.zero_new_blocks;
1794 ti->num_flush_requests = 1;
1795 ti->num_discard_requests = 0;
1798 pt->callbacks.congested_fn = pool_is_congested;
1799 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
1801 mutex_unlock(&dm_thin_pool_table.mutex);
1808 dm_put_device(ti, data_dev);
1810 dm_put_device(ti, metadata_dev);
1812 mutex_unlock(&dm_thin_pool_table.mutex);
1817 static int pool_map(struct dm_target *ti, struct bio *bio,
1818 union map_info *map_context)
1821 struct pool_c *pt = ti->private;
1822 struct pool *pool = pt->pool;
1823 unsigned long flags;
1826 * As this is a singleton target, ti->begin is always zero.
1828 spin_lock_irqsave(&pool->lock, flags);
1829 bio->bi_bdev = pt->data_dev->bdev;
1830 r = DM_MAPIO_REMAPPED;
1831 spin_unlock_irqrestore(&pool->lock, flags);
1837 * Retrieves the number of blocks of the data device from
1838 * the superblock and compares it to the actual device size,
1839 * thus resizing the data device in case it has grown.
1841 * This both copes with opening preallocated data devices in the ctr
1842 * being followed by a resume
1844 * calling the resume method individually after userspace has
1845 * grown the data device in reaction to a table event.
1847 static int pool_preresume(struct dm_target *ti)
1850 struct pool_c *pt = ti->private;
1851 struct pool *pool = pt->pool;
1852 dm_block_t data_size, sb_data_size;
1855 * Take control of the pool object.
1857 r = bind_control_target(pool, ti);
1861 data_size = ti->len >> pool->block_shift;
1862 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
1864 DMERR("failed to retrieve data device size");
1868 if (data_size < sb_data_size) {
1869 DMERR("pool target too small, is %llu blocks (expected %llu)",
1870 data_size, sb_data_size);
1873 } else if (data_size > sb_data_size) {
1874 r = dm_pool_resize_data_dev(pool->pmd, data_size);
1876 DMERR("failed to resize data device");
1880 r = dm_pool_commit_metadata(pool->pmd);
1882 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1891 static void pool_resume(struct dm_target *ti)
1893 struct pool_c *pt = ti->private;
1894 struct pool *pool = pt->pool;
1895 unsigned long flags;
1897 spin_lock_irqsave(&pool->lock, flags);
1898 pool->low_water_triggered = 0;
1899 pool->no_free_space = 0;
1900 __requeue_bios(pool);
1901 spin_unlock_irqrestore(&pool->lock, flags);
1906 static void pool_postsuspend(struct dm_target *ti)
1909 struct pool_c *pt = ti->private;
1910 struct pool *pool = pt->pool;
1912 flush_workqueue(pool->wq);
1914 r = dm_pool_commit_metadata(pool->pmd);
1916 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1918 /* FIXME: invalidate device? error the next FUA or FLUSH bio ?*/
1922 static int check_arg_count(unsigned argc, unsigned args_required)
1924 if (argc != args_required) {
1925 DMWARN("Message received with %u arguments instead of %u.",
1926 argc, args_required);
1933 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
1935 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
1936 *dev_id <= MAX_DEV_ID)
1940 DMWARN("Message received with invalid device id: %s", arg);
1945 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
1950 r = check_arg_count(argc, 2);
1954 r = read_dev_id(argv[1], &dev_id, 1);
1958 r = dm_pool_create_thin(pool->pmd, dev_id);
1960 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
1968 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
1971 dm_thin_id origin_dev_id;
1974 r = check_arg_count(argc, 3);
1978 r = read_dev_id(argv[1], &dev_id, 1);
1982 r = read_dev_id(argv[2], &origin_dev_id, 1);
1986 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
1988 DMWARN("Creation of new snapshot %s of device %s failed.",
1996 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2001 r = check_arg_count(argc, 2);
2005 r = read_dev_id(argv[1], &dev_id, 1);
2009 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2011 DMWARN("Deletion of thin device %s failed.", argv[1]);
2016 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2018 dm_thin_id old_id, new_id;
2021 r = check_arg_count(argc, 3);
2025 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2026 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2030 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2031 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2035 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2037 DMWARN("Failed to change transaction id from %s to %s.",
2046 * Messages supported:
2047 * create_thin <dev_id>
2048 * create_snap <dev_id> <origin_id>
2050 * trim <dev_id> <new_size_in_sectors>
2051 * set_transaction_id <current_trans_id> <new_trans_id>
2053 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2056 struct pool_c *pt = ti->private;
2057 struct pool *pool = pt->pool;
2059 if (!strcasecmp(argv[0], "create_thin"))
2060 r = process_create_thin_mesg(argc, argv, pool);
2062 else if (!strcasecmp(argv[0], "create_snap"))
2063 r = process_create_snap_mesg(argc, argv, pool);
2065 else if (!strcasecmp(argv[0], "delete"))
2066 r = process_delete_mesg(argc, argv, pool);
2068 else if (!strcasecmp(argv[0], "set_transaction_id"))
2069 r = process_set_transaction_id_mesg(argc, argv, pool);
2072 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2075 r = dm_pool_commit_metadata(pool->pmd);
2077 DMERR("%s message: dm_pool_commit_metadata() failed, error = %d",
2086 * <transaction id> <used metadata sectors>/<total metadata sectors>
2087 * <used data sectors>/<total data sectors> <held metadata root>
2089 static int pool_status(struct dm_target *ti, status_type_t type,
2090 char *result, unsigned maxlen)
2094 uint64_t transaction_id;
2095 dm_block_t nr_free_blocks_data;
2096 dm_block_t nr_free_blocks_metadata;
2097 dm_block_t nr_blocks_data;
2098 dm_block_t nr_blocks_metadata;
2099 dm_block_t held_root;
2100 char buf[BDEVNAME_SIZE];
2101 char buf2[BDEVNAME_SIZE];
2102 struct pool_c *pt = ti->private;
2103 struct pool *pool = pt->pool;
2106 case STATUSTYPE_INFO:
2107 r = dm_pool_get_metadata_transaction_id(pool->pmd,
2112 r = dm_pool_get_free_metadata_block_count(pool->pmd,
2113 &nr_free_blocks_metadata);
2117 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2121 r = dm_pool_get_free_block_count(pool->pmd,
2122 &nr_free_blocks_data);
2126 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2130 r = dm_pool_get_held_metadata_root(pool->pmd, &held_root);
2134 DMEMIT("%llu %llu/%llu %llu/%llu ",
2135 (unsigned long long)transaction_id,
2136 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2137 (unsigned long long)nr_blocks_metadata,
2138 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2139 (unsigned long long)nr_blocks_data);
2142 DMEMIT("%llu", held_root);
2148 case STATUSTYPE_TABLE:
2149 DMEMIT("%s %s %lu %llu ",
2150 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2151 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2152 (unsigned long)pool->sectors_per_block,
2153 (unsigned long long)pt->low_water_blocks);
2155 DMEMIT("%u ", !pool->zero_new_blocks);
2157 if (!pool->zero_new_blocks)
2158 DMEMIT("skip_block_zeroing ");
2165 static int pool_iterate_devices(struct dm_target *ti,
2166 iterate_devices_callout_fn fn, void *data)
2168 struct pool_c *pt = ti->private;
2170 return fn(ti, pt->data_dev, 0, ti->len, data);
2173 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2174 struct bio_vec *biovec, int max_size)
2176 struct pool_c *pt = ti->private;
2177 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2179 if (!q->merge_bvec_fn)
2182 bvm->bi_bdev = pt->data_dev->bdev;
2184 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2187 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2189 struct pool_c *pt = ti->private;
2190 struct pool *pool = pt->pool;
2192 blk_limits_io_min(limits, 0);
2193 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2196 static struct target_type pool_target = {
2197 .name = "thin-pool",
2198 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2199 DM_TARGET_IMMUTABLE,
2200 .version = {1, 0, 0},
2201 .module = THIS_MODULE,
2205 .postsuspend = pool_postsuspend,
2206 .preresume = pool_preresume,
2207 .resume = pool_resume,
2208 .message = pool_message,
2209 .status = pool_status,
2210 .merge = pool_merge,
2211 .iterate_devices = pool_iterate_devices,
2212 .io_hints = pool_io_hints,
2215 /*----------------------------------------------------------------
2216 * Thin target methods
2217 *--------------------------------------------------------------*/
2218 static void thin_dtr(struct dm_target *ti)
2220 struct thin_c *tc = ti->private;
2222 mutex_lock(&dm_thin_pool_table.mutex);
2224 __pool_dec(tc->pool);
2225 dm_pool_close_thin_device(tc->td);
2226 dm_put_device(ti, tc->pool_dev);
2229 mutex_unlock(&dm_thin_pool_table.mutex);
2233 * Thin target parameters:
2235 * <pool_dev> <dev_id>
2237 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2238 * dev_id: the internal device identifier
2240 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2244 struct dm_dev *pool_dev;
2245 struct mapped_device *pool_md;
2247 mutex_lock(&dm_thin_pool_table.mutex);
2250 ti->error = "Invalid argument count";
2255 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2257 ti->error = "Out of memory";
2262 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2264 ti->error = "Error opening pool device";
2267 tc->pool_dev = pool_dev;
2269 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2270 ti->error = "Invalid device id";
2275 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2277 ti->error = "Couldn't get pool mapped device";
2282 tc->pool = __pool_table_lookup(pool_md);
2284 ti->error = "Couldn't find pool object";
2286 goto bad_pool_lookup;
2288 __pool_inc(tc->pool);
2290 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
2292 ti->error = "Couldn't open thin internal device";
2296 ti->split_io = tc->pool->sectors_per_block;
2297 ti->num_flush_requests = 1;
2298 ti->num_discard_requests = 0;
2299 ti->discards_supported = 0;
2303 mutex_unlock(&dm_thin_pool_table.mutex);
2308 __pool_dec(tc->pool);
2312 dm_put_device(ti, tc->pool_dev);
2316 mutex_unlock(&dm_thin_pool_table.mutex);
2321 static int thin_map(struct dm_target *ti, struct bio *bio,
2322 union map_info *map_context)
2324 bio->bi_sector -= ti->begin;
2326 return thin_bio_map(ti, bio, map_context);
2329 static void thin_postsuspend(struct dm_target *ti)
2331 if (dm_noflush_suspending(ti))
2332 requeue_io((struct thin_c *)ti->private);
2336 * <nr mapped sectors> <highest mapped sector>
2338 static int thin_status(struct dm_target *ti, status_type_t type,
2339 char *result, unsigned maxlen)
2343 dm_block_t mapped, highest;
2344 char buf[BDEVNAME_SIZE];
2345 struct thin_c *tc = ti->private;
2351 case STATUSTYPE_INFO:
2352 r = dm_thin_get_mapped_count(tc->td, &mapped);
2356 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
2360 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
2362 DMEMIT("%llu", ((highest + 1) *
2363 tc->pool->sectors_per_block) - 1);
2368 case STATUSTYPE_TABLE:
2370 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
2371 (unsigned long) tc->dev_id);
2379 static int thin_iterate_devices(struct dm_target *ti,
2380 iterate_devices_callout_fn fn, void *data)
2383 struct thin_c *tc = ti->private;
2386 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2387 * we follow a more convoluted path through to the pool's target.
2390 return 0; /* nothing is bound */
2392 blocks = tc->pool->ti->len >> tc->pool->block_shift;
2394 return fn(ti, tc->pool_dev, 0, tc->pool->sectors_per_block * blocks, data);
2399 static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
2401 struct thin_c *tc = ti->private;
2403 blk_limits_io_min(limits, 0);
2404 blk_limits_io_opt(limits, tc->pool->sectors_per_block << SECTOR_SHIFT);
2407 static struct target_type thin_target = {
2409 .version = {1, 0, 0},
2410 .module = THIS_MODULE,
2414 .postsuspend = thin_postsuspend,
2415 .status = thin_status,
2416 .iterate_devices = thin_iterate_devices,
2417 .io_hints = thin_io_hints,
2420 /*----------------------------------------------------------------*/
2422 static int __init dm_thin_init(void)
2428 r = dm_register_target(&thin_target);
2432 r = dm_register_target(&pool_target);
2434 dm_unregister_target(&thin_target);
2439 static void dm_thin_exit(void)
2441 dm_unregister_target(&thin_target);
2442 dm_unregister_target(&pool_target);
2445 module_init(dm_thin_init);
2446 module_exit(dm_thin_exit);
2448 MODULE_DESCRIPTION(DM_NAME "device-mapper thin provisioning target");
2449 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2450 MODULE_LICENSE("GPL");