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
26 #define COMMIT_PERIOD HZ
29 * The block size of the device holding pool data must be
30 * between 64KB and 1GB.
32 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
33 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
36 * Device id is restricted to 24 bits.
38 #define MAX_DEV_ID ((1 << 24) - 1)
41 * How do we handle breaking sharing of data blocks?
42 * =================================================
44 * We use a standard copy-on-write btree to store the mappings for the
45 * devices (note I'm talking about copy-on-write of the metadata here, not
46 * the data). When you take an internal snapshot you clone the root node
47 * of the origin btree. After this there is no concept of an origin or a
48 * snapshot. They are just two device trees that happen to point to the
51 * When we get a write in we decide if it's to a shared data block using
52 * some timestamp magic. If it is, we have to break sharing.
54 * Let's say we write to a shared block in what was the origin. The
57 * i) plug io further to this physical block. (see bio_prison code).
59 * ii) quiesce any read io to that shared data block. Obviously
60 * including all devices that share this block. (see deferred_set code)
62 * iii) copy the data block to a newly allocate block. This step can be
63 * missed out if the io covers the block. (schedule_copy).
65 * iv) insert the new mapping into the origin's btree
66 * (process_prepared_mapping). This act of inserting breaks some
67 * sharing of btree nodes between the two devices. Breaking sharing only
68 * effects the btree of that specific device. Btrees for the other
69 * devices that share the block never change. The btree for the origin
70 * device as it was after the last commit is untouched, ie. we're using
71 * persistent data structures in the functional programming sense.
73 * v) unplug io to this physical block, including the io that triggered
74 * the breaking of sharing.
76 * Steps (ii) and (iii) occur in parallel.
78 * The metadata _doesn't_ need to be committed before the io continues. We
79 * get away with this because the io is always written to a _new_ block.
80 * If there's a crash, then:
82 * - The origin mapping will point to the old origin block (the shared
83 * one). This will contain the data as it was before the io that triggered
84 * the breaking of sharing came in.
86 * - The snap mapping still points to the old block. As it would after
89 * The downside of this scheme is the timestamp magic isn't perfect, and
90 * will continue to think that data block in the snapshot device is shared
91 * even after the write to the origin has broken sharing. I suspect data
92 * blocks will typically be shared by many different devices, so we're
93 * breaking sharing n + 1 times, rather than n, where n is the number of
94 * devices that reference this data block. At the moment I think the
95 * benefits far, far outweigh the disadvantages.
98 /*----------------------------------------------------------------*/
101 * Sometimes we can't deal with a bio straight away. We put them in prison
102 * where they can't cause any mischief. Bios are put in a cell identified
103 * by a key, multiple bios can be in the same cell. When the cell is
104 * subsequently unlocked the bios become available.
115 struct hlist_node list
;
116 struct bio_prison
*prison
;
119 struct bio_list bios
;
124 mempool_t
*cell_pool
;
128 struct hlist_head
*cells
;
131 static uint32_t calc_nr_buckets(unsigned nr_cells
)
136 nr_cells
= min(nr_cells
, 8192u);
145 * @nr_cells should be the number of cells you want in use _concurrently_.
146 * Don't confuse it with the number of distinct keys.
148 static struct bio_prison
*prison_create(unsigned nr_cells
)
151 uint32_t nr_buckets
= calc_nr_buckets(nr_cells
);
152 size_t len
= sizeof(struct bio_prison
) +
153 (sizeof(struct hlist_head
) * nr_buckets
);
154 struct bio_prison
*prison
= kmalloc(len
, GFP_KERNEL
);
159 spin_lock_init(&prison
->lock
);
160 prison
->cell_pool
= mempool_create_kmalloc_pool(nr_cells
,
161 sizeof(struct cell
));
162 if (!prison
->cell_pool
) {
167 prison
->nr_buckets
= nr_buckets
;
168 prison
->hash_mask
= nr_buckets
- 1;
169 prison
->cells
= (struct hlist_head
*) (prison
+ 1);
170 for (i
= 0; i
< nr_buckets
; i
++)
171 INIT_HLIST_HEAD(prison
->cells
+ i
);
176 static void prison_destroy(struct bio_prison
*prison
)
178 mempool_destroy(prison
->cell_pool
);
182 static uint32_t hash_key(struct bio_prison
*prison
, struct cell_key
*key
)
184 const unsigned long BIG_PRIME
= 4294967291UL;
185 uint64_t hash
= key
->block
* BIG_PRIME
;
187 return (uint32_t) (hash
& prison
->hash_mask
);
190 static int keys_equal(struct cell_key
*lhs
, struct cell_key
*rhs
)
192 return (lhs
->virtual == rhs
->virtual) &&
193 (lhs
->dev
== rhs
->dev
) &&
194 (lhs
->block
== rhs
->block
);
197 static struct cell
*__search_bucket(struct hlist_head
*bucket
,
198 struct cell_key
*key
)
201 struct hlist_node
*tmp
;
203 hlist_for_each_entry(cell
, tmp
, bucket
, list
)
204 if (keys_equal(&cell
->key
, key
))
211 * This may block if a new cell needs allocating. You must ensure that
212 * cells will be unlocked even if the calling thread is blocked.
214 * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
216 static int bio_detain(struct bio_prison
*prison
, struct cell_key
*key
,
217 struct bio
*inmate
, struct cell
**ref
)
221 uint32_t hash
= hash_key(prison
, key
);
222 struct cell
*cell
, *cell2
;
224 BUG_ON(hash
> prison
->nr_buckets
);
226 spin_lock_irqsave(&prison
->lock
, flags
);
228 cell
= __search_bucket(prison
->cells
+ hash
, key
);
230 bio_list_add(&cell
->bios
, inmate
);
235 * Allocate a new cell
237 spin_unlock_irqrestore(&prison
->lock
, flags
);
238 cell2
= mempool_alloc(prison
->cell_pool
, GFP_NOIO
);
239 spin_lock_irqsave(&prison
->lock
, flags
);
242 * We've been unlocked, so we have to double check that
243 * nobody else has inserted this cell in the meantime.
245 cell
= __search_bucket(prison
->cells
+ hash
, key
);
247 mempool_free(cell2
, prison
->cell_pool
);
248 bio_list_add(&cell
->bios
, inmate
);
257 cell
->prison
= prison
;
258 memcpy(&cell
->key
, key
, sizeof(cell
->key
));
259 cell
->holder
= inmate
;
260 bio_list_init(&cell
->bios
);
261 hlist_add_head(&cell
->list
, prison
->cells
+ hash
);
266 spin_unlock_irqrestore(&prison
->lock
, flags
);
274 * @inmates must have been initialised prior to this call
276 static void __cell_release(struct cell
*cell
, struct bio_list
*inmates
)
278 struct bio_prison
*prison
= cell
->prison
;
280 hlist_del(&cell
->list
);
283 bio_list_add(inmates
, cell
->holder
);
284 bio_list_merge(inmates
, &cell
->bios
);
287 mempool_free(cell
, prison
->cell_pool
);
290 static void cell_release(struct cell
*cell
, struct bio_list
*bios
)
293 struct bio_prison
*prison
= cell
->prison
;
295 spin_lock_irqsave(&prison
->lock
, flags
);
296 __cell_release(cell
, bios
);
297 spin_unlock_irqrestore(&prison
->lock
, flags
);
301 * There are a couple of places where we put a bio into a cell briefly
302 * before taking it out again. In these situations we know that no other
303 * bio may be in the cell. This function releases the cell, and also does
306 static void __cell_release_singleton(struct cell
*cell
, struct bio
*bio
)
308 BUG_ON(cell
->holder
!= bio
);
309 BUG_ON(!bio_list_empty(&cell
->bios
));
311 __cell_release(cell
, NULL
);
314 static void cell_release_singleton(struct cell
*cell
, struct bio
*bio
)
317 struct bio_prison
*prison
= cell
->prison
;
319 spin_lock_irqsave(&prison
->lock
, flags
);
320 __cell_release_singleton(cell
, bio
);
321 spin_unlock_irqrestore(&prison
->lock
, flags
);
325 * Sometimes we don't want the holder, just the additional bios.
327 static void __cell_release_no_holder(struct cell
*cell
, struct bio_list
*inmates
)
329 struct bio_prison
*prison
= cell
->prison
;
331 hlist_del(&cell
->list
);
332 bio_list_merge(inmates
, &cell
->bios
);
334 mempool_free(cell
, prison
->cell_pool
);
337 static void cell_release_no_holder(struct cell
*cell
, struct bio_list
*inmates
)
340 struct bio_prison
*prison
= cell
->prison
;
342 spin_lock_irqsave(&prison
->lock
, flags
);
343 __cell_release_no_holder(cell
, inmates
);
344 spin_unlock_irqrestore(&prison
->lock
, flags
);
347 static void cell_error(struct cell
*cell
)
349 struct bio_prison
*prison
= cell
->prison
;
350 struct bio_list bios
;
354 bio_list_init(&bios
);
356 spin_lock_irqsave(&prison
->lock
, flags
);
357 __cell_release(cell
, &bios
);
358 spin_unlock_irqrestore(&prison
->lock
, flags
);
360 while ((bio
= bio_list_pop(&bios
)))
364 /*----------------------------------------------------------------*/
367 * We use the deferred set to keep track of pending reads to shared blocks.
368 * We do this to ensure the new mapping caused by a write isn't performed
369 * until these prior reads have completed. Otherwise the insertion of the
370 * new mapping could free the old block that the read bios are mapped to.
374 struct deferred_entry
{
375 struct deferred_set
*ds
;
377 struct list_head work_items
;
380 struct deferred_set
{
382 unsigned current_entry
;
384 struct deferred_entry entries
[DEFERRED_SET_SIZE
];
387 static void ds_init(struct deferred_set
*ds
)
391 spin_lock_init(&ds
->lock
);
392 ds
->current_entry
= 0;
394 for (i
= 0; i
< DEFERRED_SET_SIZE
; i
++) {
395 ds
->entries
[i
].ds
= ds
;
396 ds
->entries
[i
].count
= 0;
397 INIT_LIST_HEAD(&ds
->entries
[i
].work_items
);
401 static struct deferred_entry
*ds_inc(struct deferred_set
*ds
)
404 struct deferred_entry
*entry
;
406 spin_lock_irqsave(&ds
->lock
, flags
);
407 entry
= ds
->entries
+ ds
->current_entry
;
409 spin_unlock_irqrestore(&ds
->lock
, flags
);
414 static unsigned ds_next(unsigned index
)
416 return (index
+ 1) % DEFERRED_SET_SIZE
;
419 static void __sweep(struct deferred_set
*ds
, struct list_head
*head
)
421 while ((ds
->sweeper
!= ds
->current_entry
) &&
422 !ds
->entries
[ds
->sweeper
].count
) {
423 list_splice_init(&ds
->entries
[ds
->sweeper
].work_items
, head
);
424 ds
->sweeper
= ds_next(ds
->sweeper
);
427 if ((ds
->sweeper
== ds
->current_entry
) && !ds
->entries
[ds
->sweeper
].count
)
428 list_splice_init(&ds
->entries
[ds
->sweeper
].work_items
, head
);
431 static void ds_dec(struct deferred_entry
*entry
, struct list_head
*head
)
435 spin_lock_irqsave(&entry
->ds
->lock
, flags
);
436 BUG_ON(!entry
->count
);
438 __sweep(entry
->ds
, head
);
439 spin_unlock_irqrestore(&entry
->ds
->lock
, flags
);
443 * Returns 1 if deferred or 0 if no pending items to delay job.
445 static int ds_add_work(struct deferred_set
*ds
, struct list_head
*work
)
451 spin_lock_irqsave(&ds
->lock
, flags
);
452 if ((ds
->sweeper
== ds
->current_entry
) &&
453 !ds
->entries
[ds
->current_entry
].count
)
456 list_add(work
, &ds
->entries
[ds
->current_entry
].work_items
);
457 next_entry
= ds_next(ds
->current_entry
);
458 if (!ds
->entries
[next_entry
].count
)
459 ds
->current_entry
= next_entry
;
461 spin_unlock_irqrestore(&ds
->lock
, flags
);
466 /*----------------------------------------------------------------*/
471 static void build_data_key(struct dm_thin_device
*td
,
472 dm_block_t b
, struct cell_key
*key
)
475 key
->dev
= dm_thin_dev_id(td
);
479 static void build_virtual_key(struct dm_thin_device
*td
, dm_block_t b
,
480 struct cell_key
*key
)
483 key
->dev
= dm_thin_dev_id(td
);
487 /*----------------------------------------------------------------*/
490 * A pool device ties together a metadata device and a data device. It
491 * also provides the interface for creating and destroying internal
496 struct pool_features
{
497 unsigned zero_new_blocks
:1;
498 unsigned discard_enabled
:1;
499 unsigned discard_passdown
:1;
503 struct list_head list
;
504 struct dm_target
*ti
; /* Only set if a pool target is bound */
506 struct mapped_device
*pool_md
;
507 struct block_device
*md_dev
;
508 struct dm_pool_metadata
*pmd
;
510 uint32_t sectors_per_block
;
511 unsigned block_shift
;
512 dm_block_t offset_mask
;
513 dm_block_t low_water_blocks
;
515 struct pool_features pf
;
516 unsigned low_water_triggered
:1; /* A dm event has been sent */
517 unsigned no_free_space
:1; /* A -ENOSPC warning has been issued */
519 struct bio_prison
*prison
;
520 struct dm_kcopyd_client
*copier
;
522 struct workqueue_struct
*wq
;
523 struct work_struct worker
;
524 struct delayed_work waker
;
527 unsigned long last_commit_jiffies
;
530 struct bio_list deferred_bios
;
531 struct bio_list deferred_flush_bios
;
532 struct list_head prepared_mappings
;
533 struct list_head prepared_discards
;
535 struct bio_list retry_on_resume_list
;
537 struct deferred_set shared_read_ds
;
538 struct deferred_set all_io_ds
;
540 struct new_mapping
*next_mapping
;
541 mempool_t
*mapping_pool
;
542 mempool_t
*endio_hook_pool
;
546 * Target context for a pool.
549 struct dm_target
*ti
;
551 struct dm_dev
*data_dev
;
552 struct dm_dev
*metadata_dev
;
553 struct dm_target_callbacks callbacks
;
555 dm_block_t low_water_blocks
;
556 struct pool_features pf
;
560 * Target context for a thin.
563 struct dm_dev
*pool_dev
;
564 struct dm_dev
*origin_dev
;
568 struct dm_thin_device
*td
;
571 /*----------------------------------------------------------------*/
574 * A global list of pools that uses a struct mapped_device as a key.
576 static struct dm_thin_pool_table
{
578 struct list_head pools
;
579 } dm_thin_pool_table
;
581 static void pool_table_init(void)
583 mutex_init(&dm_thin_pool_table
.mutex
);
584 INIT_LIST_HEAD(&dm_thin_pool_table
.pools
);
587 static void __pool_table_insert(struct pool
*pool
)
589 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
590 list_add(&pool
->list
, &dm_thin_pool_table
.pools
);
593 static void __pool_table_remove(struct pool
*pool
)
595 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
596 list_del(&pool
->list
);
599 static struct pool
*__pool_table_lookup(struct mapped_device
*md
)
601 struct pool
*pool
= NULL
, *tmp
;
603 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
605 list_for_each_entry(tmp
, &dm_thin_pool_table
.pools
, list
) {
606 if (tmp
->pool_md
== md
) {
615 static struct pool
*__pool_table_lookup_metadata_dev(struct block_device
*md_dev
)
617 struct pool
*pool
= NULL
, *tmp
;
619 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
621 list_for_each_entry(tmp
, &dm_thin_pool_table
.pools
, list
) {
622 if (tmp
->md_dev
== md_dev
) {
631 /*----------------------------------------------------------------*/
635 struct deferred_entry
*shared_read_entry
;
636 struct deferred_entry
*all_io_entry
;
637 struct new_mapping
*overwrite_mapping
;
640 static void __requeue_bio_list(struct thin_c
*tc
, struct bio_list
*master
)
643 struct bio_list bios
;
645 bio_list_init(&bios
);
646 bio_list_merge(&bios
, master
);
647 bio_list_init(master
);
649 while ((bio
= bio_list_pop(&bios
))) {
650 struct endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
652 bio_endio(bio
, DM_ENDIO_REQUEUE
);
654 bio_list_add(master
, bio
);
658 static void requeue_io(struct thin_c
*tc
)
660 struct pool
*pool
= tc
->pool
;
663 spin_lock_irqsave(&pool
->lock
, flags
);
664 __requeue_bio_list(tc
, &pool
->deferred_bios
);
665 __requeue_bio_list(tc
, &pool
->retry_on_resume_list
);
666 spin_unlock_irqrestore(&pool
->lock
, flags
);
670 * This section of code contains the logic for processing a thin device's IO.
671 * Much of the code depends on pool object resources (lists, workqueues, etc)
672 * but most is exclusively called from the thin target rather than the thin-pool
676 static dm_block_t
get_bio_block(struct thin_c
*tc
, struct bio
*bio
)
678 return bio
->bi_sector
>> tc
->pool
->block_shift
;
681 static void remap(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
)
683 struct pool
*pool
= tc
->pool
;
685 bio
->bi_bdev
= tc
->pool_dev
->bdev
;
686 bio
->bi_sector
= (block
<< pool
->block_shift
) +
687 (bio
->bi_sector
& pool
->offset_mask
);
690 static void remap_to_origin(struct thin_c
*tc
, struct bio
*bio
)
692 bio
->bi_bdev
= tc
->origin_dev
->bdev
;
695 static void issue(struct thin_c
*tc
, struct bio
*bio
)
697 struct pool
*pool
= tc
->pool
;
701 * Batch together any FUA/FLUSH bios we find and then issue
702 * a single commit for them in process_deferred_bios().
704 if (bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
)) {
705 spin_lock_irqsave(&pool
->lock
, flags
);
706 bio_list_add(&pool
->deferred_flush_bios
, bio
);
707 spin_unlock_irqrestore(&pool
->lock
, flags
);
709 generic_make_request(bio
);
712 static void remap_to_origin_and_issue(struct thin_c
*tc
, struct bio
*bio
)
714 remap_to_origin(tc
, bio
);
718 static void remap_and_issue(struct thin_c
*tc
, struct bio
*bio
,
721 remap(tc
, bio
, block
);
726 * wake_worker() is used when new work is queued and when pool_resume is
727 * ready to continue deferred IO processing.
729 static void wake_worker(struct pool
*pool
)
731 queue_work(pool
->wq
, &pool
->worker
);
734 /*----------------------------------------------------------------*/
737 * Bio endio functions.
740 struct list_head list
;
744 unsigned pass_discard
:1;
747 dm_block_t virt_block
;
748 dm_block_t data_block
;
749 struct cell
*cell
, *cell2
;
753 * If the bio covers the whole area of a block then we can avoid
754 * zeroing or copying. Instead this bio is hooked. The bio will
755 * still be in the cell, so care has to be taken to avoid issuing
759 bio_end_io_t
*saved_bi_end_io
;
762 static void __maybe_add_mapping(struct new_mapping
*m
)
764 struct pool
*pool
= m
->tc
->pool
;
766 if (m
->quiesced
&& m
->prepared
) {
767 list_add(&m
->list
, &pool
->prepared_mappings
);
772 static void copy_complete(int read_err
, unsigned long write_err
, void *context
)
775 struct new_mapping
*m
= context
;
776 struct pool
*pool
= m
->tc
->pool
;
778 m
->err
= read_err
|| write_err
? -EIO
: 0;
780 spin_lock_irqsave(&pool
->lock
, flags
);
782 __maybe_add_mapping(m
);
783 spin_unlock_irqrestore(&pool
->lock
, flags
);
786 static void overwrite_endio(struct bio
*bio
, int err
)
789 struct endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
790 struct new_mapping
*m
= h
->overwrite_mapping
;
791 struct pool
*pool
= m
->tc
->pool
;
795 spin_lock_irqsave(&pool
->lock
, flags
);
797 __maybe_add_mapping(m
);
798 spin_unlock_irqrestore(&pool
->lock
, flags
);
801 /*----------------------------------------------------------------*/
808 * Prepared mapping jobs.
812 * This sends the bios in the cell back to the deferred_bios list.
814 static void cell_defer(struct thin_c
*tc
, struct cell
*cell
,
815 dm_block_t data_block
)
817 struct pool
*pool
= tc
->pool
;
820 spin_lock_irqsave(&pool
->lock
, flags
);
821 cell_release(cell
, &pool
->deferred_bios
);
822 spin_unlock_irqrestore(&tc
->pool
->lock
, flags
);
828 * Same as cell_defer above, except it omits one particular detainee,
829 * a write bio that covers the block and has already been processed.
831 static void cell_defer_except(struct thin_c
*tc
, struct cell
*cell
)
833 struct bio_list bios
;
834 struct pool
*pool
= tc
->pool
;
837 bio_list_init(&bios
);
839 spin_lock_irqsave(&pool
->lock
, flags
);
840 cell_release_no_holder(cell
, &pool
->deferred_bios
);
841 spin_unlock_irqrestore(&pool
->lock
, flags
);
846 static void process_prepared_mapping(struct new_mapping
*m
)
848 struct thin_c
*tc
= m
->tc
;
854 bio
->bi_end_io
= m
->saved_bi_end_io
;
862 * Commit the prepared block into the mapping btree.
863 * Any I/O for this block arriving after this point will get
864 * remapped to it directly.
866 r
= dm_thin_insert_block(tc
->td
, m
->virt_block
, m
->data_block
);
868 DMERR("dm_thin_insert_block() failed");
874 * Release any bios held while the block was being provisioned.
875 * If we are processing a write bio that completely covers the block,
876 * we already processed it so can ignore it now when processing
877 * the bios in the cell.
880 cell_defer_except(tc
, m
->cell
);
883 cell_defer(tc
, m
->cell
, m
->data_block
);
886 mempool_free(m
, tc
->pool
->mapping_pool
);
889 static void process_prepared_discard(struct new_mapping
*m
)
892 struct thin_c
*tc
= m
->tc
;
894 r
= dm_thin_remove_block(tc
->td
, m
->virt_block
);
896 DMERR("dm_thin_remove_block() failed");
899 * Pass the discard down to the underlying device?
902 remap_and_issue(tc
, m
->bio
, m
->data_block
);
904 bio_endio(m
->bio
, 0);
906 cell_defer_except(tc
, m
->cell
);
907 cell_defer_except(tc
, m
->cell2
);
908 mempool_free(m
, tc
->pool
->mapping_pool
);
911 static void process_prepared(struct pool
*pool
, struct list_head
*head
,
912 void (*fn
)(struct new_mapping
*))
915 struct list_head maps
;
916 struct new_mapping
*m
, *tmp
;
918 INIT_LIST_HEAD(&maps
);
919 spin_lock_irqsave(&pool
->lock
, flags
);
920 list_splice_init(head
, &maps
);
921 spin_unlock_irqrestore(&pool
->lock
, flags
);
923 list_for_each_entry_safe(m
, tmp
, &maps
, list
)
930 static int io_overlaps_block(struct pool
*pool
, struct bio
*bio
)
932 return !(bio
->bi_sector
& pool
->offset_mask
) &&
933 (bio
->bi_size
== (pool
->sectors_per_block
<< SECTOR_SHIFT
));
937 static int io_overwrites_block(struct pool
*pool
, struct bio
*bio
)
939 return (bio_data_dir(bio
) == WRITE
) &&
940 io_overlaps_block(pool
, bio
);
943 static void save_and_set_endio(struct bio
*bio
, bio_end_io_t
**save
,
946 *save
= bio
->bi_end_io
;
950 static int ensure_next_mapping(struct pool
*pool
)
952 if (pool
->next_mapping
)
955 pool
->next_mapping
= mempool_alloc(pool
->mapping_pool
, GFP_ATOMIC
);
957 return pool
->next_mapping
? 0 : -ENOMEM
;
960 static struct new_mapping
*get_next_mapping(struct pool
*pool
)
962 struct new_mapping
*r
= pool
->next_mapping
;
964 BUG_ON(!pool
->next_mapping
);
966 pool
->next_mapping
= NULL
;
971 static void schedule_copy(struct thin_c
*tc
, dm_block_t virt_block
,
972 struct dm_dev
*origin
, dm_block_t data_origin
,
973 dm_block_t data_dest
,
974 struct cell
*cell
, struct bio
*bio
)
977 struct pool
*pool
= tc
->pool
;
978 struct new_mapping
*m
= get_next_mapping(pool
);
980 INIT_LIST_HEAD(&m
->list
);
984 m
->virt_block
= virt_block
;
985 m
->data_block
= data_dest
;
990 if (!ds_add_work(&pool
->shared_read_ds
, &m
->list
))
994 * IO to pool_dev remaps to the pool target's data_dev.
996 * If the whole block of data is being overwritten, we can issue the
997 * bio immediately. Otherwise we use kcopyd to clone the data first.
999 if (io_overwrites_block(pool
, bio
)) {
1000 struct endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1001 h
->overwrite_mapping
= m
;
1003 save_and_set_endio(bio
, &m
->saved_bi_end_io
, overwrite_endio
);
1004 remap_and_issue(tc
, bio
, data_dest
);
1006 struct dm_io_region from
, to
;
1008 from
.bdev
= origin
->bdev
;
1009 from
.sector
= data_origin
* pool
->sectors_per_block
;
1010 from
.count
= pool
->sectors_per_block
;
1012 to
.bdev
= tc
->pool_dev
->bdev
;
1013 to
.sector
= data_dest
* pool
->sectors_per_block
;
1014 to
.count
= pool
->sectors_per_block
;
1016 r
= dm_kcopyd_copy(pool
->copier
, &from
, 1, &to
,
1017 0, copy_complete
, m
);
1019 mempool_free(m
, pool
->mapping_pool
);
1020 DMERR("dm_kcopyd_copy() failed");
1026 static void schedule_internal_copy(struct thin_c
*tc
, dm_block_t virt_block
,
1027 dm_block_t data_origin
, dm_block_t data_dest
,
1028 struct cell
*cell
, struct bio
*bio
)
1030 schedule_copy(tc
, virt_block
, tc
->pool_dev
,
1031 data_origin
, data_dest
, cell
, bio
);
1034 static void schedule_external_copy(struct thin_c
*tc
, dm_block_t virt_block
,
1035 dm_block_t data_dest
,
1036 struct cell
*cell
, struct bio
*bio
)
1038 schedule_copy(tc
, virt_block
, tc
->origin_dev
,
1039 virt_block
, data_dest
, cell
, bio
);
1042 static void schedule_zero(struct thin_c
*tc
, dm_block_t virt_block
,
1043 dm_block_t data_block
, struct cell
*cell
,
1046 struct pool
*pool
= tc
->pool
;
1047 struct new_mapping
*m
= get_next_mapping(pool
);
1049 INIT_LIST_HEAD(&m
->list
);
1053 m
->virt_block
= virt_block
;
1054 m
->data_block
= data_block
;
1060 * If the whole block of data is being overwritten or we are not
1061 * zeroing pre-existing data, we can issue the bio immediately.
1062 * Otherwise we use kcopyd to zero the data first.
1064 if (!pool
->pf
.zero_new_blocks
)
1065 process_prepared_mapping(m
);
1067 else if (io_overwrites_block(pool
, bio
)) {
1068 struct endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1069 h
->overwrite_mapping
= m
;
1071 save_and_set_endio(bio
, &m
->saved_bi_end_io
, overwrite_endio
);
1072 remap_and_issue(tc
, bio
, data_block
);
1076 struct dm_io_region to
;
1078 to
.bdev
= tc
->pool_dev
->bdev
;
1079 to
.sector
= data_block
* pool
->sectors_per_block
;
1080 to
.count
= pool
->sectors_per_block
;
1082 r
= dm_kcopyd_zero(pool
->copier
, 1, &to
, 0, copy_complete
, m
);
1084 mempool_free(m
, pool
->mapping_pool
);
1085 DMERR("dm_kcopyd_zero() failed");
1091 static int alloc_data_block(struct thin_c
*tc
, dm_block_t
*result
)
1094 dm_block_t free_blocks
;
1095 unsigned long flags
;
1096 struct pool
*pool
= tc
->pool
;
1098 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
1102 if (free_blocks
<= pool
->low_water_blocks
&& !pool
->low_water_triggered
) {
1103 DMWARN("%s: reached low water mark, sending event.",
1104 dm_device_name(pool
->pool_md
));
1105 spin_lock_irqsave(&pool
->lock
, flags
);
1106 pool
->low_water_triggered
= 1;
1107 spin_unlock_irqrestore(&pool
->lock
, flags
);
1108 dm_table_event(pool
->ti
->table
);
1112 if (pool
->no_free_space
)
1116 * Try to commit to see if that will free up some
1119 r
= dm_pool_commit_metadata(pool
->pmd
);
1121 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1126 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
1131 * If we still have no space we set a flag to avoid
1132 * doing all this checking and return -ENOSPC.
1135 DMWARN("%s: no free space available.",
1136 dm_device_name(pool
->pool_md
));
1137 spin_lock_irqsave(&pool
->lock
, flags
);
1138 pool
->no_free_space
= 1;
1139 spin_unlock_irqrestore(&pool
->lock
, flags
);
1145 r
= dm_pool_alloc_data_block(pool
->pmd
, result
);
1153 * If we have run out of space, queue bios until the device is
1154 * resumed, presumably after having been reloaded with more space.
1156 static void retry_on_resume(struct bio
*bio
)
1158 struct endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1159 struct thin_c
*tc
= h
->tc
;
1160 struct pool
*pool
= tc
->pool
;
1161 unsigned long flags
;
1163 spin_lock_irqsave(&pool
->lock
, flags
);
1164 bio_list_add(&pool
->retry_on_resume_list
, bio
);
1165 spin_unlock_irqrestore(&pool
->lock
, flags
);
1168 static void no_space(struct cell
*cell
)
1171 struct bio_list bios
;
1173 bio_list_init(&bios
);
1174 cell_release(cell
, &bios
);
1176 while ((bio
= bio_list_pop(&bios
)))
1177 retry_on_resume(bio
);
1180 static void process_discard(struct thin_c
*tc
, struct bio
*bio
)
1183 unsigned long flags
;
1184 struct pool
*pool
= tc
->pool
;
1185 struct cell
*cell
, *cell2
;
1186 struct cell_key key
, key2
;
1187 dm_block_t block
= get_bio_block(tc
, bio
);
1188 struct dm_thin_lookup_result lookup_result
;
1189 struct new_mapping
*m
;
1191 build_virtual_key(tc
->td
, block
, &key
);
1192 if (bio_detain(tc
->pool
->prison
, &key
, bio
, &cell
))
1195 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1199 * Check nobody is fiddling with this pool block. This can
1200 * happen if someone's in the process of breaking sharing
1203 build_data_key(tc
->td
, lookup_result
.block
, &key2
);
1204 if (bio_detain(tc
->pool
->prison
, &key2
, bio
, &cell2
)) {
1205 cell_release_singleton(cell
, bio
);
1209 if (io_overlaps_block(pool
, bio
)) {
1211 * IO may still be going to the destination block. We must
1212 * quiesce before we can do the removal.
1214 m
= get_next_mapping(pool
);
1216 m
->pass_discard
= (!lookup_result
.shared
) & pool
->pf
.discard_passdown
;
1217 m
->virt_block
= block
;
1218 m
->data_block
= lookup_result
.block
;
1224 if (!ds_add_work(&pool
->all_io_ds
, &m
->list
)) {
1225 spin_lock_irqsave(&pool
->lock
, flags
);
1226 list_add(&m
->list
, &pool
->prepared_discards
);
1227 spin_unlock_irqrestore(&pool
->lock
, flags
);
1232 * This path is hit if people are ignoring
1233 * limits->discard_granularity. It ignores any
1234 * part of the discard that is in a subsequent
1237 sector_t offset
= bio
->bi_sector
- (block
<< pool
->block_shift
);
1238 unsigned remaining
= (pool
->sectors_per_block
- offset
) << 9;
1239 bio
->bi_size
= min(bio
->bi_size
, remaining
);
1241 cell_release_singleton(cell
, bio
);
1242 cell_release_singleton(cell2
, bio
);
1243 remap_and_issue(tc
, bio
, lookup_result
.block
);
1249 * It isn't provisioned, just forget it.
1251 cell_release_singleton(cell
, bio
);
1256 DMERR("discard: find block unexpectedly returned %d", r
);
1257 cell_release_singleton(cell
, bio
);
1263 static void break_sharing(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1264 struct cell_key
*key
,
1265 struct dm_thin_lookup_result
*lookup_result
,
1269 dm_block_t data_block
;
1271 r
= alloc_data_block(tc
, &data_block
);
1274 schedule_internal_copy(tc
, block
, lookup_result
->block
,
1275 data_block
, cell
, bio
);
1283 DMERR("%s: alloc_data_block() failed, error = %d", __func__
, r
);
1289 static void process_shared_bio(struct thin_c
*tc
, struct bio
*bio
,
1291 struct dm_thin_lookup_result
*lookup_result
)
1294 struct pool
*pool
= tc
->pool
;
1295 struct cell_key key
;
1298 * If cell is already occupied, then sharing is already in the process
1299 * of being broken so we have nothing further to do here.
1301 build_data_key(tc
->td
, lookup_result
->block
, &key
);
1302 if (bio_detain(pool
->prison
, &key
, bio
, &cell
))
1305 if (bio_data_dir(bio
) == WRITE
)
1306 break_sharing(tc
, bio
, block
, &key
, lookup_result
, cell
);
1308 struct endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1310 h
->shared_read_entry
= ds_inc(&pool
->shared_read_ds
);
1312 cell_release_singleton(cell
, bio
);
1313 remap_and_issue(tc
, bio
, lookup_result
->block
);
1317 static void provision_block(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1321 dm_block_t data_block
;
1324 * Remap empty bios (flushes) immediately, without provisioning.
1326 if (!bio
->bi_size
) {
1327 cell_release_singleton(cell
, bio
);
1328 remap_and_issue(tc
, bio
, 0);
1333 * Fill read bios with zeroes and complete them immediately.
1335 if (bio_data_dir(bio
) == READ
) {
1337 cell_release_singleton(cell
, bio
);
1342 r
= alloc_data_block(tc
, &data_block
);
1346 schedule_external_copy(tc
, block
, data_block
, cell
, bio
);
1348 schedule_zero(tc
, block
, data_block
, cell
, bio
);
1356 DMERR("%s: alloc_data_block() failed, error = %d", __func__
, r
);
1362 static void process_bio(struct thin_c
*tc
, struct bio
*bio
)
1365 dm_block_t block
= get_bio_block(tc
, bio
);
1367 struct cell_key key
;
1368 struct dm_thin_lookup_result lookup_result
;
1371 * If cell is already occupied, then the block is already
1372 * being provisioned so we have nothing further to do here.
1374 build_virtual_key(tc
->td
, block
, &key
);
1375 if (bio_detain(tc
->pool
->prison
, &key
, bio
, &cell
))
1378 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1382 * We can release this cell now. This thread is the only
1383 * one that puts bios into a cell, and we know there were
1384 * no preceding bios.
1387 * TODO: this will probably have to change when discard goes
1390 cell_release_singleton(cell
, bio
);
1392 if (lookup_result
.shared
)
1393 process_shared_bio(tc
, bio
, block
, &lookup_result
);
1395 remap_and_issue(tc
, bio
, lookup_result
.block
);
1399 if (bio_data_dir(bio
) == READ
&& tc
->origin_dev
) {
1400 cell_release_singleton(cell
, bio
);
1401 remap_to_origin_and_issue(tc
, bio
);
1403 provision_block(tc
, bio
, block
, cell
);
1407 DMERR("dm_thin_find_block() failed, error = %d", r
);
1408 cell_release_singleton(cell
, bio
);
1414 static int need_commit_due_to_time(struct pool
*pool
)
1416 return jiffies
< pool
->last_commit_jiffies
||
1417 jiffies
> pool
->last_commit_jiffies
+ COMMIT_PERIOD
;
1420 static void process_deferred_bios(struct pool
*pool
)
1422 unsigned long flags
;
1424 struct bio_list bios
;
1427 bio_list_init(&bios
);
1429 spin_lock_irqsave(&pool
->lock
, flags
);
1430 bio_list_merge(&bios
, &pool
->deferred_bios
);
1431 bio_list_init(&pool
->deferred_bios
);
1432 spin_unlock_irqrestore(&pool
->lock
, flags
);
1434 while ((bio
= bio_list_pop(&bios
))) {
1435 struct endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1436 struct thin_c
*tc
= h
->tc
;
1439 * If we've got no free new_mapping structs, and processing
1440 * this bio might require one, we pause until there are some
1441 * prepared mappings to process.
1443 if (ensure_next_mapping(pool
)) {
1444 spin_lock_irqsave(&pool
->lock
, flags
);
1445 bio_list_merge(&pool
->deferred_bios
, &bios
);
1446 spin_unlock_irqrestore(&pool
->lock
, flags
);
1451 if (bio
->bi_rw
& REQ_DISCARD
)
1452 process_discard(tc
, bio
);
1454 process_bio(tc
, bio
);
1458 * If there are any deferred flush bios, we must commit
1459 * the metadata before issuing them.
1461 bio_list_init(&bios
);
1462 spin_lock_irqsave(&pool
->lock
, flags
);
1463 bio_list_merge(&bios
, &pool
->deferred_flush_bios
);
1464 bio_list_init(&pool
->deferred_flush_bios
);
1465 spin_unlock_irqrestore(&pool
->lock
, flags
);
1467 if (bio_list_empty(&bios
) && !need_commit_due_to_time(pool
))
1470 r
= dm_pool_commit_metadata(pool
->pmd
);
1472 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1474 while ((bio
= bio_list_pop(&bios
)))
1478 pool
->last_commit_jiffies
= jiffies
;
1480 while ((bio
= bio_list_pop(&bios
)))
1481 generic_make_request(bio
);
1484 static void do_worker(struct work_struct
*ws
)
1486 struct pool
*pool
= container_of(ws
, struct pool
, worker
);
1488 process_prepared(pool
, &pool
->prepared_mappings
, process_prepared_mapping
);
1489 process_prepared(pool
, &pool
->prepared_discards
, process_prepared_discard
);
1490 process_deferred_bios(pool
);
1494 * We want to commit periodically so that not too much
1495 * unwritten data builds up.
1497 static void do_waker(struct work_struct
*ws
)
1499 struct pool
*pool
= container_of(to_delayed_work(ws
), struct pool
, waker
);
1501 queue_delayed_work(pool
->wq
, &pool
->waker
, COMMIT_PERIOD
);
1504 /*----------------------------------------------------------------*/
1507 * Mapping functions.
1511 * Called only while mapping a thin bio to hand it over to the workqueue.
1513 static void thin_defer_bio(struct thin_c
*tc
, struct bio
*bio
)
1515 unsigned long flags
;
1516 struct pool
*pool
= tc
->pool
;
1518 spin_lock_irqsave(&pool
->lock
, flags
);
1519 bio_list_add(&pool
->deferred_bios
, bio
);
1520 spin_unlock_irqrestore(&pool
->lock
, flags
);
1525 static struct endio_hook
*thin_hook_bio(struct thin_c
*tc
, struct bio
*bio
)
1527 struct pool
*pool
= tc
->pool
;
1528 struct endio_hook
*h
= mempool_alloc(pool
->endio_hook_pool
, GFP_NOIO
);
1531 h
->shared_read_entry
= NULL
;
1532 h
->all_io_entry
= bio
->bi_rw
& REQ_DISCARD
? NULL
: ds_inc(&pool
->all_io_ds
);
1533 h
->overwrite_mapping
= NULL
;
1539 * Non-blocking function called from the thin target's map function.
1541 static int thin_bio_map(struct dm_target
*ti
, struct bio
*bio
,
1542 union map_info
*map_context
)
1545 struct thin_c
*tc
= ti
->private;
1546 dm_block_t block
= get_bio_block(tc
, bio
);
1547 struct dm_thin_device
*td
= tc
->td
;
1548 struct dm_thin_lookup_result result
;
1550 map_context
->ptr
= thin_hook_bio(tc
, bio
);
1551 if (bio
->bi_rw
& (REQ_DISCARD
| REQ_FLUSH
| REQ_FUA
)) {
1552 thin_defer_bio(tc
, bio
);
1553 return DM_MAPIO_SUBMITTED
;
1556 r
= dm_thin_find_block(td
, block
, 0, &result
);
1559 * Note that we defer readahead too.
1563 if (unlikely(result
.shared
)) {
1565 * We have a race condition here between the
1566 * result.shared value returned by the lookup and
1567 * snapshot creation, which may cause new
1570 * To avoid this always quiesce the origin before
1571 * taking the snap. You want to do this anyway to
1572 * ensure a consistent application view
1575 * More distant ancestors are irrelevant. The
1576 * shared flag will be set in their case.
1578 thin_defer_bio(tc
, bio
);
1579 r
= DM_MAPIO_SUBMITTED
;
1581 remap(tc
, bio
, result
.block
);
1582 r
= DM_MAPIO_REMAPPED
;
1588 * In future, the failed dm_thin_find_block above could
1589 * provide the hint to load the metadata into cache.
1592 thin_defer_bio(tc
, bio
);
1593 r
= DM_MAPIO_SUBMITTED
;
1600 static int pool_is_congested(struct dm_target_callbacks
*cb
, int bdi_bits
)
1603 unsigned long flags
;
1604 struct pool_c
*pt
= container_of(cb
, struct pool_c
, callbacks
);
1606 spin_lock_irqsave(&pt
->pool
->lock
, flags
);
1607 r
= !bio_list_empty(&pt
->pool
->retry_on_resume_list
);
1608 spin_unlock_irqrestore(&pt
->pool
->lock
, flags
);
1611 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1612 r
= bdi_congested(&q
->backing_dev_info
, bdi_bits
);
1618 static void __requeue_bios(struct pool
*pool
)
1620 bio_list_merge(&pool
->deferred_bios
, &pool
->retry_on_resume_list
);
1621 bio_list_init(&pool
->retry_on_resume_list
);
1624 /*----------------------------------------------------------------
1625 * Binding of control targets to a pool object
1626 *--------------------------------------------------------------*/
1627 static int bind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1629 struct pool_c
*pt
= ti
->private;
1632 pool
->low_water_blocks
= pt
->low_water_blocks
;
1636 * If discard_passdown was enabled verify that the data device
1637 * supports discards. Disable discard_passdown if not; otherwise
1638 * -EOPNOTSUPP will be returned.
1640 if (pt
->pf
.discard_passdown
) {
1641 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1642 if (!q
|| !blk_queue_discard(q
)) {
1643 char buf
[BDEVNAME_SIZE
];
1644 DMWARN("Discard unsupported by data device (%s): Disabling discard passdown.",
1645 bdevname(pt
->data_dev
->bdev
, buf
));
1646 pool
->pf
.discard_passdown
= 0;
1653 static void unbind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1659 /*----------------------------------------------------------------
1661 *--------------------------------------------------------------*/
1662 /* Initialize pool features. */
1663 static void pool_features_init(struct pool_features
*pf
)
1665 pf
->zero_new_blocks
= 1;
1666 pf
->discard_enabled
= 1;
1667 pf
->discard_passdown
= 1;
1670 static void __pool_destroy(struct pool
*pool
)
1672 __pool_table_remove(pool
);
1674 if (dm_pool_metadata_close(pool
->pmd
) < 0)
1675 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1677 prison_destroy(pool
->prison
);
1678 dm_kcopyd_client_destroy(pool
->copier
);
1681 destroy_workqueue(pool
->wq
);
1683 if (pool
->next_mapping
)
1684 mempool_free(pool
->next_mapping
, pool
->mapping_pool
);
1685 mempool_destroy(pool
->mapping_pool
);
1686 mempool_destroy(pool
->endio_hook_pool
);
1690 static struct pool
*pool_create(struct mapped_device
*pool_md
,
1691 struct block_device
*metadata_dev
,
1692 unsigned long block_size
, char **error
)
1697 struct dm_pool_metadata
*pmd
;
1699 pmd
= dm_pool_metadata_open(metadata_dev
, block_size
);
1701 *error
= "Error creating metadata object";
1702 return (struct pool
*)pmd
;
1705 pool
= kmalloc(sizeof(*pool
), GFP_KERNEL
);
1707 *error
= "Error allocating memory for pool";
1708 err_p
= ERR_PTR(-ENOMEM
);
1713 pool
->sectors_per_block
= block_size
;
1714 pool
->block_shift
= ffs(block_size
) - 1;
1715 pool
->offset_mask
= block_size
- 1;
1716 pool
->low_water_blocks
= 0;
1717 pool_features_init(&pool
->pf
);
1718 pool
->prison
= prison_create(PRISON_CELLS
);
1719 if (!pool
->prison
) {
1720 *error
= "Error creating pool's bio prison";
1721 err_p
= ERR_PTR(-ENOMEM
);
1725 pool
->copier
= dm_kcopyd_client_create();
1726 if (IS_ERR(pool
->copier
)) {
1727 r
= PTR_ERR(pool
->copier
);
1728 *error
= "Error creating pool's kcopyd client";
1730 goto bad_kcopyd_client
;
1734 * Create singlethreaded workqueue that will service all devices
1735 * that use this metadata.
1737 pool
->wq
= alloc_ordered_workqueue("dm-" DM_MSG_PREFIX
, WQ_MEM_RECLAIM
);
1739 *error
= "Error creating pool's workqueue";
1740 err_p
= ERR_PTR(-ENOMEM
);
1744 INIT_WORK(&pool
->worker
, do_worker
);
1745 INIT_DELAYED_WORK(&pool
->waker
, do_waker
);
1746 spin_lock_init(&pool
->lock
);
1747 bio_list_init(&pool
->deferred_bios
);
1748 bio_list_init(&pool
->deferred_flush_bios
);
1749 INIT_LIST_HEAD(&pool
->prepared_mappings
);
1750 INIT_LIST_HEAD(&pool
->prepared_discards
);
1751 pool
->low_water_triggered
= 0;
1752 pool
->no_free_space
= 0;
1753 bio_list_init(&pool
->retry_on_resume_list
);
1754 ds_init(&pool
->shared_read_ds
);
1755 ds_init(&pool
->all_io_ds
);
1757 pool
->next_mapping
= NULL
;
1758 pool
->mapping_pool
=
1759 mempool_create_kmalloc_pool(MAPPING_POOL_SIZE
, sizeof(struct new_mapping
));
1760 if (!pool
->mapping_pool
) {
1761 *error
= "Error creating pool's mapping mempool";
1762 err_p
= ERR_PTR(-ENOMEM
);
1763 goto bad_mapping_pool
;
1766 pool
->endio_hook_pool
=
1767 mempool_create_kmalloc_pool(ENDIO_HOOK_POOL_SIZE
, sizeof(struct endio_hook
));
1768 if (!pool
->endio_hook_pool
) {
1769 *error
= "Error creating pool's endio_hook mempool";
1770 err_p
= ERR_PTR(-ENOMEM
);
1771 goto bad_endio_hook_pool
;
1773 pool
->ref_count
= 1;
1774 pool
->last_commit_jiffies
= jiffies
;
1775 pool
->pool_md
= pool_md
;
1776 pool
->md_dev
= metadata_dev
;
1777 __pool_table_insert(pool
);
1781 bad_endio_hook_pool
:
1782 mempool_destroy(pool
->mapping_pool
);
1784 destroy_workqueue(pool
->wq
);
1786 dm_kcopyd_client_destroy(pool
->copier
);
1788 prison_destroy(pool
->prison
);
1792 if (dm_pool_metadata_close(pmd
))
1793 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1798 static void __pool_inc(struct pool
*pool
)
1800 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1804 static void __pool_dec(struct pool
*pool
)
1806 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1807 BUG_ON(!pool
->ref_count
);
1808 if (!--pool
->ref_count
)
1809 __pool_destroy(pool
);
1812 static struct pool
*__pool_find(struct mapped_device
*pool_md
,
1813 struct block_device
*metadata_dev
,
1814 unsigned long block_size
, char **error
,
1817 struct pool
*pool
= __pool_table_lookup_metadata_dev(metadata_dev
);
1820 if (pool
->pool_md
!= pool_md
)
1821 return ERR_PTR(-EBUSY
);
1825 pool
= __pool_table_lookup(pool_md
);
1827 if (pool
->md_dev
!= metadata_dev
)
1828 return ERR_PTR(-EINVAL
);
1832 pool
= pool_create(pool_md
, metadata_dev
, block_size
, error
);
1840 /*----------------------------------------------------------------
1841 * Pool target methods
1842 *--------------------------------------------------------------*/
1843 static void pool_dtr(struct dm_target
*ti
)
1845 struct pool_c
*pt
= ti
->private;
1847 mutex_lock(&dm_thin_pool_table
.mutex
);
1849 unbind_control_target(pt
->pool
, ti
);
1850 __pool_dec(pt
->pool
);
1851 dm_put_device(ti
, pt
->metadata_dev
);
1852 dm_put_device(ti
, pt
->data_dev
);
1855 mutex_unlock(&dm_thin_pool_table
.mutex
);
1858 static int parse_pool_features(struct dm_arg_set
*as
, struct pool_features
*pf
,
1859 struct dm_target
*ti
)
1863 const char *arg_name
;
1865 static struct dm_arg _args
[] = {
1866 {0, 3, "Invalid number of pool feature arguments"},
1870 * No feature arguments supplied.
1875 r
= dm_read_arg_group(_args
, as
, &argc
, &ti
->error
);
1879 while (argc
&& !r
) {
1880 arg_name
= dm_shift_arg(as
);
1883 if (!strcasecmp(arg_name
, "skip_block_zeroing")) {
1884 pf
->zero_new_blocks
= 0;
1886 } else if (!strcasecmp(arg_name
, "ignore_discard")) {
1887 pf
->discard_enabled
= 0;
1889 } else if (!strcasecmp(arg_name
, "no_discard_passdown")) {
1890 pf
->discard_passdown
= 0;
1894 ti
->error
= "Unrecognised pool feature requested";
1902 * thin-pool <metadata dev> <data dev>
1903 * <data block size (sectors)>
1904 * <low water mark (blocks)>
1905 * [<#feature args> [<arg>]*]
1907 * Optional feature arguments are:
1908 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1909 * ignore_discard: disable discard
1910 * no_discard_passdown: don't pass discards down to the data device
1912 static int pool_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
1914 int r
, pool_created
= 0;
1917 struct pool_features pf
;
1918 struct dm_arg_set as
;
1919 struct dm_dev
*data_dev
;
1920 unsigned long block_size
;
1921 dm_block_t low_water_blocks
;
1922 struct dm_dev
*metadata_dev
;
1923 sector_t metadata_dev_size
;
1924 char b
[BDEVNAME_SIZE
];
1927 * FIXME Remove validation from scope of lock.
1929 mutex_lock(&dm_thin_pool_table
.mutex
);
1932 ti
->error
= "Invalid argument count";
1939 r
= dm_get_device(ti
, argv
[0], FMODE_READ
| FMODE_WRITE
, &metadata_dev
);
1941 ti
->error
= "Error opening metadata block device";
1945 metadata_dev_size
= i_size_read(metadata_dev
->bdev
->bd_inode
) >> SECTOR_SHIFT
;
1946 if (metadata_dev_size
> THIN_METADATA_MAX_SECTORS_WARNING
)
1947 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1948 bdevname(metadata_dev
->bdev
, b
), THIN_METADATA_MAX_SECTORS
);
1950 r
= dm_get_device(ti
, argv
[1], FMODE_READ
| FMODE_WRITE
, &data_dev
);
1952 ti
->error
= "Error getting data device";
1956 if (kstrtoul(argv
[2], 10, &block_size
) || !block_size
||
1957 block_size
< DATA_DEV_BLOCK_SIZE_MIN_SECTORS
||
1958 block_size
> DATA_DEV_BLOCK_SIZE_MAX_SECTORS
||
1959 !is_power_of_2(block_size
)) {
1960 ti
->error
= "Invalid block size";
1965 if (kstrtoull(argv
[3], 10, (unsigned long long *)&low_water_blocks
)) {
1966 ti
->error
= "Invalid low water mark";
1972 * Set default pool features.
1974 pool_features_init(&pf
);
1976 dm_consume_args(&as
, 4);
1977 r
= parse_pool_features(&as
, &pf
, ti
);
1981 pt
= kzalloc(sizeof(*pt
), GFP_KERNEL
);
1987 pool
= __pool_find(dm_table_get_md(ti
->table
), metadata_dev
->bdev
,
1988 block_size
, &ti
->error
, &pool_created
);
1995 * 'pool_created' reflects whether this is the first table load.
1996 * Top level discard support is not allowed to be changed after
1997 * initial load. This would require a pool reload to trigger thin
2000 if (!pool_created
&& pf
.discard_enabled
!= pool
->pf
.discard_enabled
) {
2001 ti
->error
= "Discard support cannot be disabled once enabled";
2003 goto out_flags_changed
;
2008 pt
->metadata_dev
= metadata_dev
;
2009 pt
->data_dev
= data_dev
;
2010 pt
->low_water_blocks
= low_water_blocks
;
2012 ti
->num_flush_requests
= 1;
2014 * Only need to enable discards if the pool should pass
2015 * them down to the data device. The thin device's discard
2016 * processing will cause mappings to be removed from the btree.
2018 if (pf
.discard_enabled
&& pf
.discard_passdown
) {
2019 ti
->num_discard_requests
= 1;
2021 * Setting 'discards_supported' circumvents the normal
2022 * stacking of discard limits (this keeps the pool and
2023 * thin devices' discard limits consistent).
2025 ti
->discards_supported
= 1;
2029 pt
->callbacks
.congested_fn
= pool_is_congested
;
2030 dm_table_add_target_callbacks(ti
->table
, &pt
->callbacks
);
2032 mutex_unlock(&dm_thin_pool_table
.mutex
);
2041 dm_put_device(ti
, data_dev
);
2043 dm_put_device(ti
, metadata_dev
);
2045 mutex_unlock(&dm_thin_pool_table
.mutex
);
2050 static int pool_map(struct dm_target
*ti
, struct bio
*bio
,
2051 union map_info
*map_context
)
2054 struct pool_c
*pt
= ti
->private;
2055 struct pool
*pool
= pt
->pool
;
2056 unsigned long flags
;
2059 * As this is a singleton target, ti->begin is always zero.
2061 spin_lock_irqsave(&pool
->lock
, flags
);
2062 bio
->bi_bdev
= pt
->data_dev
->bdev
;
2063 r
= DM_MAPIO_REMAPPED
;
2064 spin_unlock_irqrestore(&pool
->lock
, flags
);
2070 * Retrieves the number of blocks of the data device from
2071 * the superblock and compares it to the actual device size,
2072 * thus resizing the data device in case it has grown.
2074 * This both copes with opening preallocated data devices in the ctr
2075 * being followed by a resume
2077 * calling the resume method individually after userspace has
2078 * grown the data device in reaction to a table event.
2080 static int pool_preresume(struct dm_target
*ti
)
2083 struct pool_c
*pt
= ti
->private;
2084 struct pool
*pool
= pt
->pool
;
2085 dm_block_t data_size
, sb_data_size
;
2088 * Take control of the pool object.
2090 r
= bind_control_target(pool
, ti
);
2094 data_size
= ti
->len
>> pool
->block_shift
;
2095 r
= dm_pool_get_data_dev_size(pool
->pmd
, &sb_data_size
);
2097 DMERR("failed to retrieve data device size");
2101 if (data_size
< sb_data_size
) {
2102 DMERR("pool target too small, is %llu blocks (expected %llu)",
2103 data_size
, sb_data_size
);
2106 } else if (data_size
> sb_data_size
) {
2107 r
= dm_pool_resize_data_dev(pool
->pmd
, data_size
);
2109 DMERR("failed to resize data device");
2113 r
= dm_pool_commit_metadata(pool
->pmd
);
2115 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2124 static void pool_resume(struct dm_target
*ti
)
2126 struct pool_c
*pt
= ti
->private;
2127 struct pool
*pool
= pt
->pool
;
2128 unsigned long flags
;
2130 spin_lock_irqsave(&pool
->lock
, flags
);
2131 pool
->low_water_triggered
= 0;
2132 pool
->no_free_space
= 0;
2133 __requeue_bios(pool
);
2134 spin_unlock_irqrestore(&pool
->lock
, flags
);
2136 do_waker(&pool
->waker
.work
);
2139 static void pool_postsuspend(struct dm_target
*ti
)
2142 struct pool_c
*pt
= ti
->private;
2143 struct pool
*pool
= pt
->pool
;
2145 cancel_delayed_work(&pool
->waker
);
2146 flush_workqueue(pool
->wq
);
2148 r
= dm_pool_commit_metadata(pool
->pmd
);
2150 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2152 /* FIXME: invalidate device? error the next FUA or FLUSH bio ?*/
2156 static int check_arg_count(unsigned argc
, unsigned args_required
)
2158 if (argc
!= args_required
) {
2159 DMWARN("Message received with %u arguments instead of %u.",
2160 argc
, args_required
);
2167 static int read_dev_id(char *arg
, dm_thin_id
*dev_id
, int warning
)
2169 if (!kstrtoull(arg
, 10, (unsigned long long *)dev_id
) &&
2170 *dev_id
<= MAX_DEV_ID
)
2174 DMWARN("Message received with invalid device id: %s", arg
);
2179 static int process_create_thin_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2184 r
= check_arg_count(argc
, 2);
2188 r
= read_dev_id(argv
[1], &dev_id
, 1);
2192 r
= dm_pool_create_thin(pool
->pmd
, dev_id
);
2194 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2202 static int process_create_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2205 dm_thin_id origin_dev_id
;
2208 r
= check_arg_count(argc
, 3);
2212 r
= read_dev_id(argv
[1], &dev_id
, 1);
2216 r
= read_dev_id(argv
[2], &origin_dev_id
, 1);
2220 r
= dm_pool_create_snap(pool
->pmd
, dev_id
, origin_dev_id
);
2222 DMWARN("Creation of new snapshot %s of device %s failed.",
2230 static int process_delete_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2235 r
= check_arg_count(argc
, 2);
2239 r
= read_dev_id(argv
[1], &dev_id
, 1);
2243 r
= dm_pool_delete_thin_device(pool
->pmd
, dev_id
);
2245 DMWARN("Deletion of thin device %s failed.", argv
[1]);
2250 static int process_set_transaction_id_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2252 dm_thin_id old_id
, new_id
;
2255 r
= check_arg_count(argc
, 3);
2259 if (kstrtoull(argv
[1], 10, (unsigned long long *)&old_id
)) {
2260 DMWARN("set_transaction_id message: Unrecognised id %s.", argv
[1]);
2264 if (kstrtoull(argv
[2], 10, (unsigned long long *)&new_id
)) {
2265 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv
[2]);
2269 r
= dm_pool_set_metadata_transaction_id(pool
->pmd
, old_id
, new_id
);
2271 DMWARN("Failed to change transaction id from %s to %s.",
2280 * Messages supported:
2281 * create_thin <dev_id>
2282 * create_snap <dev_id> <origin_id>
2284 * trim <dev_id> <new_size_in_sectors>
2285 * set_transaction_id <current_trans_id> <new_trans_id>
2287 static int pool_message(struct dm_target
*ti
, unsigned argc
, char **argv
)
2290 struct pool_c
*pt
= ti
->private;
2291 struct pool
*pool
= pt
->pool
;
2293 if (!strcasecmp(argv
[0], "create_thin"))
2294 r
= process_create_thin_mesg(argc
, argv
, pool
);
2296 else if (!strcasecmp(argv
[0], "create_snap"))
2297 r
= process_create_snap_mesg(argc
, argv
, pool
);
2299 else if (!strcasecmp(argv
[0], "delete"))
2300 r
= process_delete_mesg(argc
, argv
, pool
);
2302 else if (!strcasecmp(argv
[0], "set_transaction_id"))
2303 r
= process_set_transaction_id_mesg(argc
, argv
, pool
);
2306 DMWARN("Unrecognised thin pool target message received: %s", argv
[0]);
2309 r
= dm_pool_commit_metadata(pool
->pmd
);
2311 DMERR("%s message: dm_pool_commit_metadata() failed, error = %d",
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 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 r
= dm_pool_get_metadata_transaction_id(pool
->pmd
,
2346 r
= dm_pool_get_free_metadata_block_count(pool
->pmd
,
2347 &nr_free_blocks_metadata
);
2351 r
= dm_pool_get_metadata_dev_size(pool
->pmd
, &nr_blocks_metadata
);
2355 r
= dm_pool_get_free_block_count(pool
->pmd
,
2356 &nr_free_blocks_data
);
2360 r
= dm_pool_get_data_dev_size(pool
->pmd
, &nr_blocks_data
);
2364 r
= dm_pool_get_held_metadata_root(pool
->pmd
, &held_root
);
2368 DMEMIT("%llu %llu/%llu %llu/%llu ",
2369 (unsigned long long)transaction_id
,
2370 (unsigned long long)(nr_blocks_metadata
- nr_free_blocks_metadata
),
2371 (unsigned long long)nr_blocks_metadata
,
2372 (unsigned long long)(nr_blocks_data
- nr_free_blocks_data
),
2373 (unsigned long long)nr_blocks_data
);
2376 DMEMIT("%llu", held_root
);
2382 case STATUSTYPE_TABLE
:
2383 DMEMIT("%s %s %lu %llu ",
2384 format_dev_t(buf
, pt
->metadata_dev
->bdev
->bd_dev
),
2385 format_dev_t(buf2
, pt
->data_dev
->bdev
->bd_dev
),
2386 (unsigned long)pool
->sectors_per_block
,
2387 (unsigned long long)pt
->low_water_blocks
);
2389 count
= !pool
->pf
.zero_new_blocks
+ !pool
->pf
.discard_enabled
+
2390 !pt
->pf
.discard_passdown
;
2391 DMEMIT("%u ", count
);
2393 if (!pool
->pf
.zero_new_blocks
)
2394 DMEMIT("skip_block_zeroing ");
2396 if (!pool
->pf
.discard_enabled
)
2397 DMEMIT("ignore_discard ");
2399 if (!pt
->pf
.discard_passdown
)
2400 DMEMIT("no_discard_passdown ");
2408 static int pool_iterate_devices(struct dm_target
*ti
,
2409 iterate_devices_callout_fn fn
, void *data
)
2411 struct pool_c
*pt
= ti
->private;
2413 return fn(ti
, pt
->data_dev
, 0, ti
->len
, data
);
2416 static int pool_merge(struct dm_target
*ti
, struct bvec_merge_data
*bvm
,
2417 struct bio_vec
*biovec
, int max_size
)
2419 struct pool_c
*pt
= ti
->private;
2420 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
2422 if (!q
->merge_bvec_fn
)
2425 bvm
->bi_bdev
= pt
->data_dev
->bdev
;
2427 return min(max_size
, q
->merge_bvec_fn(q
, bvm
, biovec
));
2430 static void set_discard_limits(struct pool
*pool
, struct queue_limits
*limits
)
2433 * FIXME: these limits may be incompatible with the pool's data device
2435 limits
->max_discard_sectors
= pool
->sectors_per_block
;
2438 * This is just a hint, and not enforced. We have to cope with
2439 * bios that overlap 2 blocks.
2441 limits
->discard_granularity
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
2442 limits
->discard_zeroes_data
= pool
->pf
.zero_new_blocks
;
2445 static void pool_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
2447 struct pool_c
*pt
= ti
->private;
2448 struct pool
*pool
= pt
->pool
;
2450 blk_limits_io_min(limits
, 0);
2451 blk_limits_io_opt(limits
, pool
->sectors_per_block
<< SECTOR_SHIFT
);
2452 if (pool
->pf
.discard_enabled
)
2453 set_discard_limits(pool
, limits
);
2456 static struct target_type pool_target
= {
2457 .name
= "thin-pool",
2458 .features
= DM_TARGET_SINGLETON
| DM_TARGET_ALWAYS_WRITEABLE
|
2459 DM_TARGET_IMMUTABLE
,
2460 .version
= {1, 1, 0},
2461 .module
= THIS_MODULE
,
2465 .postsuspend
= pool_postsuspend
,
2466 .preresume
= pool_preresume
,
2467 .resume
= pool_resume
,
2468 .message
= pool_message
,
2469 .status
= pool_status
,
2470 .merge
= pool_merge
,
2471 .iterate_devices
= pool_iterate_devices
,
2472 .io_hints
= pool_io_hints
,
2475 /*----------------------------------------------------------------
2476 * Thin target methods
2477 *--------------------------------------------------------------*/
2478 static void thin_dtr(struct dm_target
*ti
)
2480 struct thin_c
*tc
= ti
->private;
2482 mutex_lock(&dm_thin_pool_table
.mutex
);
2484 __pool_dec(tc
->pool
);
2485 dm_pool_close_thin_device(tc
->td
);
2486 dm_put_device(ti
, tc
->pool_dev
);
2488 dm_put_device(ti
, tc
->origin_dev
);
2491 mutex_unlock(&dm_thin_pool_table
.mutex
);
2495 * Thin target parameters:
2497 * <pool_dev> <dev_id> [origin_dev]
2499 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2500 * dev_id: the internal device identifier
2501 * origin_dev: a device external to the pool that should act as the origin
2503 * If the pool device has discards disabled, they get disabled for the thin
2506 static int thin_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
2510 struct dm_dev
*pool_dev
, *origin_dev
;
2511 struct mapped_device
*pool_md
;
2513 mutex_lock(&dm_thin_pool_table
.mutex
);
2515 if (argc
!= 2 && argc
!= 3) {
2516 ti
->error
= "Invalid argument count";
2521 tc
= ti
->private = kzalloc(sizeof(*tc
), GFP_KERNEL
);
2523 ti
->error
= "Out of memory";
2529 r
= dm_get_device(ti
, argv
[2], FMODE_READ
, &origin_dev
);
2531 ti
->error
= "Error opening origin device";
2532 goto bad_origin_dev
;
2534 tc
->origin_dev
= origin_dev
;
2537 r
= dm_get_device(ti
, argv
[0], dm_table_get_mode(ti
->table
), &pool_dev
);
2539 ti
->error
= "Error opening pool device";
2542 tc
->pool_dev
= pool_dev
;
2544 if (read_dev_id(argv
[1], (unsigned long long *)&tc
->dev_id
, 0)) {
2545 ti
->error
= "Invalid device id";
2550 pool_md
= dm_get_md(tc
->pool_dev
->bdev
->bd_dev
);
2552 ti
->error
= "Couldn't get pool mapped device";
2557 tc
->pool
= __pool_table_lookup(pool_md
);
2559 ti
->error
= "Couldn't find pool object";
2561 goto bad_pool_lookup
;
2563 __pool_inc(tc
->pool
);
2565 r
= dm_pool_open_thin_device(tc
->pool
->pmd
, tc
->dev_id
, &tc
->td
);
2567 ti
->error
= "Couldn't open thin internal device";
2571 ti
->split_io
= tc
->pool
->sectors_per_block
;
2572 ti
->num_flush_requests
= 1;
2574 /* In case the pool supports discards, pass them on. */
2575 if (tc
->pool
->pf
.discard_enabled
) {
2576 ti
->discards_supported
= 1;
2577 ti
->num_discard_requests
= 1;
2582 mutex_unlock(&dm_thin_pool_table
.mutex
);
2587 __pool_dec(tc
->pool
);
2591 dm_put_device(ti
, tc
->pool_dev
);
2594 dm_put_device(ti
, tc
->origin_dev
);
2598 mutex_unlock(&dm_thin_pool_table
.mutex
);
2603 static int thin_map(struct dm_target
*ti
, struct bio
*bio
,
2604 union map_info
*map_context
)
2606 bio
->bi_sector
= dm_target_offset(ti
, bio
->bi_sector
);
2608 return thin_bio_map(ti
, bio
, map_context
);
2611 static int thin_endio(struct dm_target
*ti
,
2612 struct bio
*bio
, int err
,
2613 union map_info
*map_context
)
2615 unsigned long flags
;
2616 struct endio_hook
*h
= map_context
->ptr
;
2617 struct list_head work
;
2618 struct new_mapping
*m
, *tmp
;
2619 struct pool
*pool
= h
->tc
->pool
;
2621 if (h
->shared_read_entry
) {
2622 INIT_LIST_HEAD(&work
);
2623 ds_dec(h
->shared_read_entry
, &work
);
2625 spin_lock_irqsave(&pool
->lock
, flags
);
2626 list_for_each_entry_safe(m
, tmp
, &work
, list
) {
2629 __maybe_add_mapping(m
);
2631 spin_unlock_irqrestore(&pool
->lock
, flags
);
2634 if (h
->all_io_entry
) {
2635 INIT_LIST_HEAD(&work
);
2636 ds_dec(h
->all_io_entry
, &work
);
2637 spin_lock_irqsave(&pool
->lock
, flags
);
2638 list_for_each_entry_safe(m
, tmp
, &work
, list
)
2639 list_add(&m
->list
, &pool
->prepared_discards
);
2640 spin_unlock_irqrestore(&pool
->lock
, flags
);
2643 mempool_free(h
, pool
->endio_hook_pool
);
2648 static void thin_postsuspend(struct dm_target
*ti
)
2650 if (dm_noflush_suspending(ti
))
2651 requeue_io((struct thin_c
*)ti
->private);
2655 * <nr mapped sectors> <highest mapped sector>
2657 static int thin_status(struct dm_target
*ti
, status_type_t type
,
2658 char *result
, unsigned maxlen
)
2662 dm_block_t mapped
, highest
;
2663 char buf
[BDEVNAME_SIZE
];
2664 struct thin_c
*tc
= ti
->private;
2670 case STATUSTYPE_INFO
:
2671 r
= dm_thin_get_mapped_count(tc
->td
, &mapped
);
2675 r
= dm_thin_get_highest_mapped_block(tc
->td
, &highest
);
2679 DMEMIT("%llu ", mapped
* tc
->pool
->sectors_per_block
);
2681 DMEMIT("%llu", ((highest
+ 1) *
2682 tc
->pool
->sectors_per_block
) - 1);
2687 case STATUSTYPE_TABLE
:
2689 format_dev_t(buf
, tc
->pool_dev
->bdev
->bd_dev
),
2690 (unsigned long) tc
->dev_id
);
2692 DMEMIT(" %s", format_dev_t(buf
, tc
->origin_dev
->bdev
->bd_dev
));
2700 static int thin_iterate_devices(struct dm_target
*ti
,
2701 iterate_devices_callout_fn fn
, void *data
)
2704 struct thin_c
*tc
= ti
->private;
2707 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2708 * we follow a more convoluted path through to the pool's target.
2711 return 0; /* nothing is bound */
2713 blocks
= tc
->pool
->ti
->len
>> tc
->pool
->block_shift
;
2715 return fn(ti
, tc
->pool_dev
, 0, tc
->pool
->sectors_per_block
* blocks
, data
);
2720 static void thin_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
2722 struct thin_c
*tc
= ti
->private;
2723 struct pool
*pool
= tc
->pool
;
2725 blk_limits_io_min(limits
, 0);
2726 blk_limits_io_opt(limits
, pool
->sectors_per_block
<< SECTOR_SHIFT
);
2727 set_discard_limits(pool
, limits
);
2730 static struct target_type thin_target
= {
2732 .version
= {1, 1, 0},
2733 .module
= THIS_MODULE
,
2737 .end_io
= thin_endio
,
2738 .postsuspend
= thin_postsuspend
,
2739 .status
= thin_status
,
2740 .iterate_devices
= thin_iterate_devices
,
2741 .io_hints
= thin_io_hints
,
2744 /*----------------------------------------------------------------*/
2746 static int __init
dm_thin_init(void)
2752 r
= dm_register_target(&thin_target
);
2756 r
= dm_register_target(&pool_target
);
2758 dm_unregister_target(&thin_target
);
2763 static void dm_thin_exit(void)
2765 dm_unregister_target(&thin_target
);
2766 dm_unregister_target(&pool_target
);
2769 module_init(dm_thin_init
);
2770 module_exit(dm_thin_exit
);
2772 MODULE_DESCRIPTION(DM_NAME
" thin provisioning target");
2773 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2774 MODULE_LICENSE("GPL");