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.
114 struct dm_bio_prison_cell
{
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);
144 static struct kmem_cache
*_cell_cache
;
147 * @nr_cells should be the number of cells you want in use _concurrently_.
148 * Don't confuse it with the number of distinct keys.
150 static struct bio_prison
*prison_create(unsigned nr_cells
)
153 uint32_t nr_buckets
= calc_nr_buckets(nr_cells
);
154 size_t len
= sizeof(struct bio_prison
) +
155 (sizeof(struct hlist_head
) * nr_buckets
);
156 struct bio_prison
*prison
= kmalloc(len
, GFP_KERNEL
);
161 spin_lock_init(&prison
->lock
);
162 prison
->cell_pool
= mempool_create_slab_pool(nr_cells
, _cell_cache
);
163 if (!prison
->cell_pool
) {
168 prison
->nr_buckets
= nr_buckets
;
169 prison
->hash_mask
= nr_buckets
- 1;
170 prison
->cells
= (struct hlist_head
*) (prison
+ 1);
171 for (i
= 0; i
< nr_buckets
; i
++)
172 INIT_HLIST_HEAD(prison
->cells
+ i
);
177 static void prison_destroy(struct bio_prison
*prison
)
179 mempool_destroy(prison
->cell_pool
);
183 static uint32_t hash_key(struct bio_prison
*prison
, struct cell_key
*key
)
185 const unsigned long BIG_PRIME
= 4294967291UL;
186 uint64_t hash
= key
->block
* BIG_PRIME
;
188 return (uint32_t) (hash
& prison
->hash_mask
);
191 static int keys_equal(struct cell_key
*lhs
, struct cell_key
*rhs
)
193 return (lhs
->virtual == rhs
->virtual) &&
194 (lhs
->dev
== rhs
->dev
) &&
195 (lhs
->block
== rhs
->block
);
198 static struct dm_bio_prison_cell
*__search_bucket(struct hlist_head
*bucket
,
199 struct cell_key
*key
)
201 struct dm_bio_prison_cell
*cell
;
202 struct hlist_node
*tmp
;
204 hlist_for_each_entry(cell
, tmp
, bucket
, list
)
205 if (keys_equal(&cell
->key
, key
))
212 * This may block if a new cell needs allocating. You must ensure that
213 * cells will be unlocked even if the calling thread is blocked.
215 * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
217 static int bio_detain(struct bio_prison
*prison
, struct cell_key
*key
,
218 struct bio
*inmate
, struct dm_bio_prison_cell
**ref
)
222 uint32_t hash
= hash_key(prison
, key
);
223 struct dm_bio_prison_cell
*cell
, *cell2
;
225 BUG_ON(hash
> prison
->nr_buckets
);
227 spin_lock_irqsave(&prison
->lock
, flags
);
229 cell
= __search_bucket(prison
->cells
+ hash
, key
);
231 bio_list_add(&cell
->bios
, inmate
);
236 * Allocate a new cell
238 spin_unlock_irqrestore(&prison
->lock
, flags
);
239 cell2
= mempool_alloc(prison
->cell_pool
, GFP_NOIO
);
240 spin_lock_irqsave(&prison
->lock
, flags
);
243 * We've been unlocked, so we have to double check that
244 * nobody else has inserted this cell in the meantime.
246 cell
= __search_bucket(prison
->cells
+ hash
, key
);
248 mempool_free(cell2
, prison
->cell_pool
);
249 bio_list_add(&cell
->bios
, inmate
);
258 cell
->prison
= prison
;
259 memcpy(&cell
->key
, key
, sizeof(cell
->key
));
260 cell
->holder
= inmate
;
261 bio_list_init(&cell
->bios
);
262 hlist_add_head(&cell
->list
, prison
->cells
+ hash
);
267 spin_unlock_irqrestore(&prison
->lock
, flags
);
275 * @inmates must have been initialised prior to this call
277 static void __cell_release(struct dm_bio_prison_cell
*cell
, struct bio_list
*inmates
)
279 struct bio_prison
*prison
= cell
->prison
;
281 hlist_del(&cell
->list
);
284 bio_list_add(inmates
, cell
->holder
);
285 bio_list_merge(inmates
, &cell
->bios
);
288 mempool_free(cell
, prison
->cell_pool
);
291 static void cell_release(struct dm_bio_prison_cell
*cell
, struct bio_list
*bios
)
294 struct bio_prison
*prison
= cell
->prison
;
296 spin_lock_irqsave(&prison
->lock
, flags
);
297 __cell_release(cell
, bios
);
298 spin_unlock_irqrestore(&prison
->lock
, flags
);
302 * There are a couple of places where we put a bio into a cell briefly
303 * before taking it out again. In these situations we know that no other
304 * bio may be in the cell. This function releases the cell, and also does
307 static void __cell_release_singleton(struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
309 BUG_ON(cell
->holder
!= bio
);
310 BUG_ON(!bio_list_empty(&cell
->bios
));
312 __cell_release(cell
, NULL
);
315 static void cell_release_singleton(struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
318 struct bio_prison
*prison
= cell
->prison
;
320 spin_lock_irqsave(&prison
->lock
, flags
);
321 __cell_release_singleton(cell
, bio
);
322 spin_unlock_irqrestore(&prison
->lock
, flags
);
326 * Sometimes we don't want the holder, just the additional bios.
328 static void __cell_release_no_holder(struct dm_bio_prison_cell
*cell
,
329 struct bio_list
*inmates
)
331 struct bio_prison
*prison
= cell
->prison
;
333 hlist_del(&cell
->list
);
334 bio_list_merge(inmates
, &cell
->bios
);
336 mempool_free(cell
, prison
->cell_pool
);
339 static void cell_release_no_holder(struct dm_bio_prison_cell
*cell
,
340 struct bio_list
*inmates
)
343 struct bio_prison
*prison
= cell
->prison
;
345 spin_lock_irqsave(&prison
->lock
, flags
);
346 __cell_release_no_holder(cell
, inmates
);
347 spin_unlock_irqrestore(&prison
->lock
, flags
);
350 static void cell_error(struct dm_bio_prison_cell
*cell
)
352 struct bio_prison
*prison
= cell
->prison
;
353 struct bio_list bios
;
357 bio_list_init(&bios
);
359 spin_lock_irqsave(&prison
->lock
, flags
);
360 __cell_release(cell
, &bios
);
361 spin_unlock_irqrestore(&prison
->lock
, flags
);
363 while ((bio
= bio_list_pop(&bios
)))
367 /*----------------------------------------------------------------*/
370 * We use the deferred set to keep track of pending reads to shared blocks.
371 * We do this to ensure the new mapping caused by a write isn't performed
372 * until these prior reads have completed. Otherwise the insertion of the
373 * new mapping could free the old block that the read bios are mapped to.
377 struct deferred_entry
{
378 struct deferred_set
*ds
;
380 struct list_head work_items
;
383 struct deferred_set
{
385 unsigned current_entry
;
387 struct deferred_entry entries
[DEFERRED_SET_SIZE
];
390 static void ds_init(struct deferred_set
*ds
)
394 spin_lock_init(&ds
->lock
);
395 ds
->current_entry
= 0;
397 for (i
= 0; i
< DEFERRED_SET_SIZE
; i
++) {
398 ds
->entries
[i
].ds
= ds
;
399 ds
->entries
[i
].count
= 0;
400 INIT_LIST_HEAD(&ds
->entries
[i
].work_items
);
404 static struct deferred_entry
*ds_inc(struct deferred_set
*ds
)
407 struct deferred_entry
*entry
;
409 spin_lock_irqsave(&ds
->lock
, flags
);
410 entry
= ds
->entries
+ ds
->current_entry
;
412 spin_unlock_irqrestore(&ds
->lock
, flags
);
417 static unsigned ds_next(unsigned index
)
419 return (index
+ 1) % DEFERRED_SET_SIZE
;
422 static void __sweep(struct deferred_set
*ds
, struct list_head
*head
)
424 while ((ds
->sweeper
!= ds
->current_entry
) &&
425 !ds
->entries
[ds
->sweeper
].count
) {
426 list_splice_init(&ds
->entries
[ds
->sweeper
].work_items
, head
);
427 ds
->sweeper
= ds_next(ds
->sweeper
);
430 if ((ds
->sweeper
== ds
->current_entry
) && !ds
->entries
[ds
->sweeper
].count
)
431 list_splice_init(&ds
->entries
[ds
->sweeper
].work_items
, head
);
434 static void ds_dec(struct deferred_entry
*entry
, struct list_head
*head
)
438 spin_lock_irqsave(&entry
->ds
->lock
, flags
);
439 BUG_ON(!entry
->count
);
441 __sweep(entry
->ds
, head
);
442 spin_unlock_irqrestore(&entry
->ds
->lock
, flags
);
446 * Returns 1 if deferred or 0 if no pending items to delay job.
448 static int ds_add_work(struct deferred_set
*ds
, struct list_head
*work
)
454 spin_lock_irqsave(&ds
->lock
, flags
);
455 if ((ds
->sweeper
== ds
->current_entry
) &&
456 !ds
->entries
[ds
->current_entry
].count
)
459 list_add(work
, &ds
->entries
[ds
->current_entry
].work_items
);
460 next_entry
= ds_next(ds
->current_entry
);
461 if (!ds
->entries
[next_entry
].count
)
462 ds
->current_entry
= next_entry
;
464 spin_unlock_irqrestore(&ds
->lock
, flags
);
469 /*----------------------------------------------------------------*/
474 static void build_data_key(struct dm_thin_device
*td
,
475 dm_block_t b
, struct cell_key
*key
)
478 key
->dev
= dm_thin_dev_id(td
);
482 static void build_virtual_key(struct dm_thin_device
*td
, dm_block_t b
,
483 struct cell_key
*key
)
486 key
->dev
= dm_thin_dev_id(td
);
490 /*----------------------------------------------------------------*/
493 * A pool device ties together a metadata device and a data device. It
494 * also provides the interface for creating and destroying internal
497 struct dm_thin_new_mapping
;
499 struct pool_features
{
500 unsigned zero_new_blocks
:1;
501 unsigned discard_enabled
:1;
502 unsigned discard_passdown
:1;
506 struct list_head list
;
507 struct dm_target
*ti
; /* Only set if a pool target is bound */
509 struct mapped_device
*pool_md
;
510 struct block_device
*md_dev
;
511 struct dm_pool_metadata
*pmd
;
513 uint32_t sectors_per_block
;
514 unsigned block_shift
;
515 dm_block_t offset_mask
;
516 dm_block_t low_water_blocks
;
518 struct pool_features pf
;
519 unsigned low_water_triggered
:1; /* A dm event has been sent */
520 unsigned no_free_space
:1; /* A -ENOSPC warning has been issued */
522 struct bio_prison
*prison
;
523 struct dm_kcopyd_client
*copier
;
525 struct workqueue_struct
*wq
;
526 struct work_struct worker
;
527 struct delayed_work waker
;
530 unsigned long last_commit_jiffies
;
533 struct bio_list deferred_bios
;
534 struct bio_list deferred_flush_bios
;
535 struct list_head prepared_mappings
;
536 struct list_head prepared_discards
;
538 struct bio_list retry_on_resume_list
;
540 struct deferred_set shared_read_ds
;
541 struct deferred_set all_io_ds
;
543 struct dm_thin_new_mapping
*next_mapping
;
544 mempool_t
*mapping_pool
;
545 mempool_t
*endio_hook_pool
;
549 * Target context for a pool.
552 struct dm_target
*ti
;
554 struct dm_dev
*data_dev
;
555 struct dm_dev
*metadata_dev
;
556 struct dm_target_callbacks callbacks
;
558 dm_block_t low_water_blocks
;
559 struct pool_features pf
;
563 * Target context for a thin.
566 struct dm_dev
*pool_dev
;
567 struct dm_dev
*origin_dev
;
571 struct dm_thin_device
*td
;
574 /*----------------------------------------------------------------*/
577 * A global list of pools that uses a struct mapped_device as a key.
579 static struct dm_thin_pool_table
{
581 struct list_head pools
;
582 } dm_thin_pool_table
;
584 static void pool_table_init(void)
586 mutex_init(&dm_thin_pool_table
.mutex
);
587 INIT_LIST_HEAD(&dm_thin_pool_table
.pools
);
590 static void __pool_table_insert(struct pool
*pool
)
592 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
593 list_add(&pool
->list
, &dm_thin_pool_table
.pools
);
596 static void __pool_table_remove(struct pool
*pool
)
598 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
599 list_del(&pool
->list
);
602 static struct pool
*__pool_table_lookup(struct mapped_device
*md
)
604 struct pool
*pool
= NULL
, *tmp
;
606 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
608 list_for_each_entry(tmp
, &dm_thin_pool_table
.pools
, list
) {
609 if (tmp
->pool_md
== md
) {
618 static struct pool
*__pool_table_lookup_metadata_dev(struct block_device
*md_dev
)
620 struct pool
*pool
= NULL
, *tmp
;
622 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
624 list_for_each_entry(tmp
, &dm_thin_pool_table
.pools
, list
) {
625 if (tmp
->md_dev
== md_dev
) {
634 /*----------------------------------------------------------------*/
636 struct dm_thin_endio_hook
{
638 struct deferred_entry
*shared_read_entry
;
639 struct deferred_entry
*all_io_entry
;
640 struct dm_thin_new_mapping
*overwrite_mapping
;
643 static void __requeue_bio_list(struct thin_c
*tc
, struct bio_list
*master
)
646 struct bio_list bios
;
648 bio_list_init(&bios
);
649 bio_list_merge(&bios
, master
);
650 bio_list_init(master
);
652 while ((bio
= bio_list_pop(&bios
))) {
653 struct dm_thin_endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
656 bio_endio(bio
, DM_ENDIO_REQUEUE
);
658 bio_list_add(master
, bio
);
662 static void requeue_io(struct thin_c
*tc
)
664 struct pool
*pool
= tc
->pool
;
667 spin_lock_irqsave(&pool
->lock
, flags
);
668 __requeue_bio_list(tc
, &pool
->deferred_bios
);
669 __requeue_bio_list(tc
, &pool
->retry_on_resume_list
);
670 spin_unlock_irqrestore(&pool
->lock
, flags
);
674 * This section of code contains the logic for processing a thin device's IO.
675 * Much of the code depends on pool object resources (lists, workqueues, etc)
676 * but most is exclusively called from the thin target rather than the thin-pool
680 static dm_block_t
get_bio_block(struct thin_c
*tc
, struct bio
*bio
)
682 return bio
->bi_sector
>> tc
->pool
->block_shift
;
685 static void remap(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
)
687 struct pool
*pool
= tc
->pool
;
689 bio
->bi_bdev
= tc
->pool_dev
->bdev
;
690 bio
->bi_sector
= (block
<< pool
->block_shift
) +
691 (bio
->bi_sector
& pool
->offset_mask
);
694 static void remap_to_origin(struct thin_c
*tc
, struct bio
*bio
)
696 bio
->bi_bdev
= tc
->origin_dev
->bdev
;
699 static void issue(struct thin_c
*tc
, struct bio
*bio
)
701 struct pool
*pool
= tc
->pool
;
705 * Batch together any FUA/FLUSH bios we find and then issue
706 * a single commit for them in process_deferred_bios().
708 if (bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
)) {
709 spin_lock_irqsave(&pool
->lock
, flags
);
710 bio_list_add(&pool
->deferred_flush_bios
, bio
);
711 spin_unlock_irqrestore(&pool
->lock
, flags
);
713 generic_make_request(bio
);
716 static void remap_to_origin_and_issue(struct thin_c
*tc
, struct bio
*bio
)
718 remap_to_origin(tc
, bio
);
722 static void remap_and_issue(struct thin_c
*tc
, struct bio
*bio
,
725 remap(tc
, bio
, block
);
730 * wake_worker() is used when new work is queued and when pool_resume is
731 * ready to continue deferred IO processing.
733 static void wake_worker(struct pool
*pool
)
735 queue_work(pool
->wq
, &pool
->worker
);
738 /*----------------------------------------------------------------*/
741 * Bio endio functions.
743 struct dm_thin_new_mapping
{
744 struct list_head list
;
748 unsigned pass_discard
:1;
751 dm_block_t virt_block
;
752 dm_block_t data_block
;
753 struct dm_bio_prison_cell
*cell
, *cell2
;
757 * If the bio covers the whole area of a block then we can avoid
758 * zeroing or copying. Instead this bio is hooked. The bio will
759 * still be in the cell, so care has to be taken to avoid issuing
763 bio_end_io_t
*saved_bi_end_io
;
766 static void __maybe_add_mapping(struct dm_thin_new_mapping
*m
)
768 struct pool
*pool
= m
->tc
->pool
;
770 if (m
->quiesced
&& m
->prepared
) {
771 list_add(&m
->list
, &pool
->prepared_mappings
);
776 static void copy_complete(int read_err
, unsigned long write_err
, void *context
)
779 struct dm_thin_new_mapping
*m
= context
;
780 struct pool
*pool
= m
->tc
->pool
;
782 m
->err
= read_err
|| write_err
? -EIO
: 0;
784 spin_lock_irqsave(&pool
->lock
, flags
);
786 __maybe_add_mapping(m
);
787 spin_unlock_irqrestore(&pool
->lock
, flags
);
790 static void overwrite_endio(struct bio
*bio
, int err
)
793 struct dm_thin_endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
794 struct dm_thin_new_mapping
*m
= h
->overwrite_mapping
;
795 struct pool
*pool
= m
->tc
->pool
;
799 spin_lock_irqsave(&pool
->lock
, flags
);
801 __maybe_add_mapping(m
);
802 spin_unlock_irqrestore(&pool
->lock
, flags
);
805 /*----------------------------------------------------------------*/
812 * Prepared mapping jobs.
816 * This sends the bios in the cell back to the deferred_bios list.
818 static void cell_defer(struct thin_c
*tc
, struct dm_bio_prison_cell
*cell
,
819 dm_block_t data_block
)
821 struct pool
*pool
= tc
->pool
;
824 spin_lock_irqsave(&pool
->lock
, flags
);
825 cell_release(cell
, &pool
->deferred_bios
);
826 spin_unlock_irqrestore(&tc
->pool
->lock
, flags
);
832 * Same as cell_defer above, except it omits one particular detainee,
833 * a write bio that covers the block and has already been processed.
835 static void cell_defer_except(struct thin_c
*tc
, struct dm_bio_prison_cell
*cell
)
837 struct bio_list bios
;
838 struct pool
*pool
= tc
->pool
;
841 bio_list_init(&bios
);
843 spin_lock_irqsave(&pool
->lock
, flags
);
844 cell_release_no_holder(cell
, &pool
->deferred_bios
);
845 spin_unlock_irqrestore(&pool
->lock
, flags
);
850 static void process_prepared_mapping(struct dm_thin_new_mapping
*m
)
852 struct thin_c
*tc
= m
->tc
;
858 bio
->bi_end_io
= m
->saved_bi_end_io
;
866 * Commit the prepared block into the mapping btree.
867 * Any I/O for this block arriving after this point will get
868 * remapped to it directly.
870 r
= dm_thin_insert_block(tc
->td
, m
->virt_block
, m
->data_block
);
872 DMERR("dm_thin_insert_block() failed");
878 * Release any bios held while the block was being provisioned.
879 * If we are processing a write bio that completely covers the block,
880 * we already processed it so can ignore it now when processing
881 * the bios in the cell.
884 cell_defer_except(tc
, m
->cell
);
887 cell_defer(tc
, m
->cell
, m
->data_block
);
890 mempool_free(m
, tc
->pool
->mapping_pool
);
893 static void process_prepared_discard(struct dm_thin_new_mapping
*m
)
896 struct thin_c
*tc
= m
->tc
;
898 r
= dm_thin_remove_block(tc
->td
, m
->virt_block
);
900 DMERR("dm_thin_remove_block() failed");
903 * Pass the discard down to the underlying device?
906 remap_and_issue(tc
, m
->bio
, m
->data_block
);
908 bio_endio(m
->bio
, 0);
910 cell_defer_except(tc
, m
->cell
);
911 cell_defer_except(tc
, m
->cell2
);
912 mempool_free(m
, tc
->pool
->mapping_pool
);
915 static void process_prepared(struct pool
*pool
, struct list_head
*head
,
916 void (*fn
)(struct dm_thin_new_mapping
*))
919 struct list_head maps
;
920 struct dm_thin_new_mapping
*m
, *tmp
;
922 INIT_LIST_HEAD(&maps
);
923 spin_lock_irqsave(&pool
->lock
, flags
);
924 list_splice_init(head
, &maps
);
925 spin_unlock_irqrestore(&pool
->lock
, flags
);
927 list_for_each_entry_safe(m
, tmp
, &maps
, list
)
934 static int io_overlaps_block(struct pool
*pool
, struct bio
*bio
)
936 return !(bio
->bi_sector
& pool
->offset_mask
) &&
937 (bio
->bi_size
== (pool
->sectors_per_block
<< SECTOR_SHIFT
));
941 static int io_overwrites_block(struct pool
*pool
, struct bio
*bio
)
943 return (bio_data_dir(bio
) == WRITE
) &&
944 io_overlaps_block(pool
, bio
);
947 static void save_and_set_endio(struct bio
*bio
, bio_end_io_t
**save
,
950 *save
= bio
->bi_end_io
;
954 static int ensure_next_mapping(struct pool
*pool
)
956 if (pool
->next_mapping
)
959 pool
->next_mapping
= mempool_alloc(pool
->mapping_pool
, GFP_ATOMIC
);
961 return pool
->next_mapping
? 0 : -ENOMEM
;
964 static struct dm_thin_new_mapping
*get_next_mapping(struct pool
*pool
)
966 struct dm_thin_new_mapping
*r
= pool
->next_mapping
;
968 BUG_ON(!pool
->next_mapping
);
970 pool
->next_mapping
= NULL
;
975 static void schedule_copy(struct thin_c
*tc
, dm_block_t virt_block
,
976 struct dm_dev
*origin
, dm_block_t data_origin
,
977 dm_block_t data_dest
,
978 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
981 struct pool
*pool
= tc
->pool
;
982 struct dm_thin_new_mapping
*m
= get_next_mapping(pool
);
984 INIT_LIST_HEAD(&m
->list
);
988 m
->virt_block
= virt_block
;
989 m
->data_block
= data_dest
;
994 if (!ds_add_work(&pool
->shared_read_ds
, &m
->list
))
998 * IO to pool_dev remaps to the pool target's data_dev.
1000 * If the whole block of data is being overwritten, we can issue the
1001 * bio immediately. Otherwise we use kcopyd to clone the data first.
1003 if (io_overwrites_block(pool
, bio
)) {
1004 struct dm_thin_endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1006 h
->overwrite_mapping
= m
;
1008 save_and_set_endio(bio
, &m
->saved_bi_end_io
, overwrite_endio
);
1009 remap_and_issue(tc
, bio
, data_dest
);
1011 struct dm_io_region from
, to
;
1013 from
.bdev
= origin
->bdev
;
1014 from
.sector
= data_origin
* pool
->sectors_per_block
;
1015 from
.count
= pool
->sectors_per_block
;
1017 to
.bdev
= tc
->pool_dev
->bdev
;
1018 to
.sector
= data_dest
* pool
->sectors_per_block
;
1019 to
.count
= pool
->sectors_per_block
;
1021 r
= dm_kcopyd_copy(pool
->copier
, &from
, 1, &to
,
1022 0, copy_complete
, m
);
1024 mempool_free(m
, pool
->mapping_pool
);
1025 DMERR("dm_kcopyd_copy() failed");
1031 static void schedule_internal_copy(struct thin_c
*tc
, dm_block_t virt_block
,
1032 dm_block_t data_origin
, dm_block_t data_dest
,
1033 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
1035 schedule_copy(tc
, virt_block
, tc
->pool_dev
,
1036 data_origin
, data_dest
, cell
, bio
);
1039 static void schedule_external_copy(struct thin_c
*tc
, dm_block_t virt_block
,
1040 dm_block_t data_dest
,
1041 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
1043 schedule_copy(tc
, virt_block
, tc
->origin_dev
,
1044 virt_block
, data_dest
, cell
, bio
);
1047 static void schedule_zero(struct thin_c
*tc
, dm_block_t virt_block
,
1048 dm_block_t data_block
, struct dm_bio_prison_cell
*cell
,
1051 struct pool
*pool
= tc
->pool
;
1052 struct dm_thin_new_mapping
*m
= get_next_mapping(pool
);
1054 INIT_LIST_HEAD(&m
->list
);
1058 m
->virt_block
= virt_block
;
1059 m
->data_block
= data_block
;
1065 * If the whole block of data is being overwritten or we are not
1066 * zeroing pre-existing data, we can issue the bio immediately.
1067 * Otherwise we use kcopyd to zero the data first.
1069 if (!pool
->pf
.zero_new_blocks
)
1070 process_prepared_mapping(m
);
1072 else if (io_overwrites_block(pool
, bio
)) {
1073 struct dm_thin_endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1075 h
->overwrite_mapping
= m
;
1077 save_and_set_endio(bio
, &m
->saved_bi_end_io
, overwrite_endio
);
1078 remap_and_issue(tc
, bio
, data_block
);
1081 struct dm_io_region to
;
1083 to
.bdev
= tc
->pool_dev
->bdev
;
1084 to
.sector
= data_block
* pool
->sectors_per_block
;
1085 to
.count
= pool
->sectors_per_block
;
1087 r
= dm_kcopyd_zero(pool
->copier
, 1, &to
, 0, copy_complete
, m
);
1089 mempool_free(m
, pool
->mapping_pool
);
1090 DMERR("dm_kcopyd_zero() failed");
1096 static int alloc_data_block(struct thin_c
*tc
, dm_block_t
*result
)
1099 dm_block_t free_blocks
;
1100 unsigned long flags
;
1101 struct pool
*pool
= tc
->pool
;
1103 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
1107 if (free_blocks
<= pool
->low_water_blocks
&& !pool
->low_water_triggered
) {
1108 DMWARN("%s: reached low water mark, sending event.",
1109 dm_device_name(pool
->pool_md
));
1110 spin_lock_irqsave(&pool
->lock
, flags
);
1111 pool
->low_water_triggered
= 1;
1112 spin_unlock_irqrestore(&pool
->lock
, flags
);
1113 dm_table_event(pool
->ti
->table
);
1117 if (pool
->no_free_space
)
1121 * Try to commit to see if that will free up some
1124 r
= dm_pool_commit_metadata(pool
->pmd
);
1126 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1131 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
1136 * If we still have no space we set a flag to avoid
1137 * doing all this checking and return -ENOSPC.
1140 DMWARN("%s: no free space available.",
1141 dm_device_name(pool
->pool_md
));
1142 spin_lock_irqsave(&pool
->lock
, flags
);
1143 pool
->no_free_space
= 1;
1144 spin_unlock_irqrestore(&pool
->lock
, flags
);
1150 r
= dm_pool_alloc_data_block(pool
->pmd
, result
);
1158 * If we have run out of space, queue bios until the device is
1159 * resumed, presumably after having been reloaded with more space.
1161 static void retry_on_resume(struct bio
*bio
)
1163 struct dm_thin_endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1164 struct thin_c
*tc
= h
->tc
;
1165 struct pool
*pool
= tc
->pool
;
1166 unsigned long flags
;
1168 spin_lock_irqsave(&pool
->lock
, flags
);
1169 bio_list_add(&pool
->retry_on_resume_list
, bio
);
1170 spin_unlock_irqrestore(&pool
->lock
, flags
);
1173 static void no_space(struct dm_bio_prison_cell
*cell
)
1176 struct bio_list bios
;
1178 bio_list_init(&bios
);
1179 cell_release(cell
, &bios
);
1181 while ((bio
= bio_list_pop(&bios
)))
1182 retry_on_resume(bio
);
1185 static void process_discard(struct thin_c
*tc
, struct bio
*bio
)
1188 unsigned long flags
;
1189 struct pool
*pool
= tc
->pool
;
1190 struct dm_bio_prison_cell
*cell
, *cell2
;
1191 struct cell_key key
, key2
;
1192 dm_block_t block
= get_bio_block(tc
, bio
);
1193 struct dm_thin_lookup_result lookup_result
;
1194 struct dm_thin_new_mapping
*m
;
1196 build_virtual_key(tc
->td
, block
, &key
);
1197 if (bio_detain(tc
->pool
->prison
, &key
, bio
, &cell
))
1200 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1204 * Check nobody is fiddling with this pool block. This can
1205 * happen if someone's in the process of breaking sharing
1208 build_data_key(tc
->td
, lookup_result
.block
, &key2
);
1209 if (bio_detain(tc
->pool
->prison
, &key2
, bio
, &cell2
)) {
1210 cell_release_singleton(cell
, bio
);
1214 if (io_overlaps_block(pool
, bio
)) {
1216 * IO may still be going to the destination block. We must
1217 * quiesce before we can do the removal.
1219 m
= get_next_mapping(pool
);
1221 m
->pass_discard
= (!lookup_result
.shared
) & pool
->pf
.discard_passdown
;
1222 m
->virt_block
= block
;
1223 m
->data_block
= lookup_result
.block
;
1229 if (!ds_add_work(&pool
->all_io_ds
, &m
->list
)) {
1230 spin_lock_irqsave(&pool
->lock
, flags
);
1231 list_add(&m
->list
, &pool
->prepared_discards
);
1232 spin_unlock_irqrestore(&pool
->lock
, flags
);
1237 * This path is hit if people are ignoring
1238 * limits->discard_granularity. It ignores any
1239 * part of the discard that is in a subsequent
1242 sector_t offset
= bio
->bi_sector
- (block
<< pool
->block_shift
);
1243 unsigned remaining
= (pool
->sectors_per_block
- offset
) << 9;
1244 bio
->bi_size
= min(bio
->bi_size
, remaining
);
1246 cell_release_singleton(cell
, bio
);
1247 cell_release_singleton(cell2
, bio
);
1248 remap_and_issue(tc
, bio
, lookup_result
.block
);
1254 * It isn't provisioned, just forget it.
1256 cell_release_singleton(cell
, bio
);
1261 DMERR("discard: find block unexpectedly returned %d", r
);
1262 cell_release_singleton(cell
, bio
);
1268 static void break_sharing(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1269 struct cell_key
*key
,
1270 struct dm_thin_lookup_result
*lookup_result
,
1271 struct dm_bio_prison_cell
*cell
)
1274 dm_block_t data_block
;
1276 r
= alloc_data_block(tc
, &data_block
);
1279 schedule_internal_copy(tc
, block
, lookup_result
->block
,
1280 data_block
, cell
, bio
);
1288 DMERR("%s: alloc_data_block() failed, error = %d", __func__
, r
);
1294 static void process_shared_bio(struct thin_c
*tc
, struct bio
*bio
,
1296 struct dm_thin_lookup_result
*lookup_result
)
1298 struct dm_bio_prison_cell
*cell
;
1299 struct pool
*pool
= tc
->pool
;
1300 struct cell_key key
;
1303 * If cell is already occupied, then sharing is already in the process
1304 * of being broken so we have nothing further to do here.
1306 build_data_key(tc
->td
, lookup_result
->block
, &key
);
1307 if (bio_detain(pool
->prison
, &key
, bio
, &cell
))
1310 if (bio_data_dir(bio
) == WRITE
)
1311 break_sharing(tc
, bio
, block
, &key
, lookup_result
, cell
);
1313 struct dm_thin_endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1315 h
->shared_read_entry
= ds_inc(&pool
->shared_read_ds
);
1317 cell_release_singleton(cell
, bio
);
1318 remap_and_issue(tc
, bio
, lookup_result
->block
);
1322 static void provision_block(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1323 struct dm_bio_prison_cell
*cell
)
1326 dm_block_t data_block
;
1329 * Remap empty bios (flushes) immediately, without provisioning.
1331 if (!bio
->bi_size
) {
1332 cell_release_singleton(cell
, bio
);
1333 remap_and_issue(tc
, bio
, 0);
1338 * Fill read bios with zeroes and complete them immediately.
1340 if (bio_data_dir(bio
) == READ
) {
1342 cell_release_singleton(cell
, bio
);
1347 r
= alloc_data_block(tc
, &data_block
);
1351 schedule_external_copy(tc
, block
, data_block
, cell
, bio
);
1353 schedule_zero(tc
, block
, data_block
, cell
, bio
);
1361 DMERR("%s: alloc_data_block() failed, error = %d", __func__
, r
);
1367 static void process_bio(struct thin_c
*tc
, struct bio
*bio
)
1370 dm_block_t block
= get_bio_block(tc
, bio
);
1371 struct dm_bio_prison_cell
*cell
;
1372 struct cell_key key
;
1373 struct dm_thin_lookup_result lookup_result
;
1376 * If cell is already occupied, then the block is already
1377 * being provisioned so we have nothing further to do here.
1379 build_virtual_key(tc
->td
, block
, &key
);
1380 if (bio_detain(tc
->pool
->prison
, &key
, bio
, &cell
))
1383 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1387 * We can release this cell now. This thread is the only
1388 * one that puts bios into a cell, and we know there were
1389 * no preceding bios.
1392 * TODO: this will probably have to change when discard goes
1395 cell_release_singleton(cell
, bio
);
1397 if (lookup_result
.shared
)
1398 process_shared_bio(tc
, bio
, block
, &lookup_result
);
1400 remap_and_issue(tc
, bio
, lookup_result
.block
);
1404 if (bio_data_dir(bio
) == READ
&& tc
->origin_dev
) {
1405 cell_release_singleton(cell
, bio
);
1406 remap_to_origin_and_issue(tc
, bio
);
1408 provision_block(tc
, bio
, block
, cell
);
1412 DMERR("dm_thin_find_block() failed, error = %d", r
);
1413 cell_release_singleton(cell
, bio
);
1419 static int need_commit_due_to_time(struct pool
*pool
)
1421 return jiffies
< pool
->last_commit_jiffies
||
1422 jiffies
> pool
->last_commit_jiffies
+ COMMIT_PERIOD
;
1425 static void process_deferred_bios(struct pool
*pool
)
1427 unsigned long flags
;
1429 struct bio_list bios
;
1432 bio_list_init(&bios
);
1434 spin_lock_irqsave(&pool
->lock
, flags
);
1435 bio_list_merge(&bios
, &pool
->deferred_bios
);
1436 bio_list_init(&pool
->deferred_bios
);
1437 spin_unlock_irqrestore(&pool
->lock
, flags
);
1439 while ((bio
= bio_list_pop(&bios
))) {
1440 struct dm_thin_endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1441 struct thin_c
*tc
= h
->tc
;
1444 * If we've got no free new_mapping structs, and processing
1445 * this bio might require one, we pause until there are some
1446 * prepared mappings to process.
1448 if (ensure_next_mapping(pool
)) {
1449 spin_lock_irqsave(&pool
->lock
, flags
);
1450 bio_list_merge(&pool
->deferred_bios
, &bios
);
1451 spin_unlock_irqrestore(&pool
->lock
, flags
);
1456 if (bio
->bi_rw
& REQ_DISCARD
)
1457 process_discard(tc
, bio
);
1459 process_bio(tc
, bio
);
1463 * If there are any deferred flush bios, we must commit
1464 * the metadata before issuing them.
1466 bio_list_init(&bios
);
1467 spin_lock_irqsave(&pool
->lock
, flags
);
1468 bio_list_merge(&bios
, &pool
->deferred_flush_bios
);
1469 bio_list_init(&pool
->deferred_flush_bios
);
1470 spin_unlock_irqrestore(&pool
->lock
, flags
);
1472 if (bio_list_empty(&bios
) && !need_commit_due_to_time(pool
))
1475 r
= dm_pool_commit_metadata(pool
->pmd
);
1477 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1479 while ((bio
= bio_list_pop(&bios
)))
1483 pool
->last_commit_jiffies
= jiffies
;
1485 while ((bio
= bio_list_pop(&bios
)))
1486 generic_make_request(bio
);
1489 static void do_worker(struct work_struct
*ws
)
1491 struct pool
*pool
= container_of(ws
, struct pool
, worker
);
1493 process_prepared(pool
, &pool
->prepared_mappings
, process_prepared_mapping
);
1494 process_prepared(pool
, &pool
->prepared_discards
, process_prepared_discard
);
1495 process_deferred_bios(pool
);
1499 * We want to commit periodically so that not too much
1500 * unwritten data builds up.
1502 static void do_waker(struct work_struct
*ws
)
1504 struct pool
*pool
= container_of(to_delayed_work(ws
), struct pool
, waker
);
1506 queue_delayed_work(pool
->wq
, &pool
->waker
, COMMIT_PERIOD
);
1509 /*----------------------------------------------------------------*/
1512 * Mapping functions.
1516 * Called only while mapping a thin bio to hand it over to the workqueue.
1518 static void thin_defer_bio(struct thin_c
*tc
, struct bio
*bio
)
1520 unsigned long flags
;
1521 struct pool
*pool
= tc
->pool
;
1523 spin_lock_irqsave(&pool
->lock
, flags
);
1524 bio_list_add(&pool
->deferred_bios
, bio
);
1525 spin_unlock_irqrestore(&pool
->lock
, flags
);
1530 static struct dm_thin_endio_hook
*thin_hook_bio(struct thin_c
*tc
, struct bio
*bio
)
1532 struct pool
*pool
= tc
->pool
;
1533 struct dm_thin_endio_hook
*h
= mempool_alloc(pool
->endio_hook_pool
, GFP_NOIO
);
1536 h
->shared_read_entry
= NULL
;
1537 h
->all_io_entry
= bio
->bi_rw
& REQ_DISCARD
? NULL
: ds_inc(&pool
->all_io_ds
);
1538 h
->overwrite_mapping
= NULL
;
1544 * Non-blocking function called from the thin target's map function.
1546 static int thin_bio_map(struct dm_target
*ti
, struct bio
*bio
,
1547 union map_info
*map_context
)
1550 struct thin_c
*tc
= ti
->private;
1551 dm_block_t block
= get_bio_block(tc
, bio
);
1552 struct dm_thin_device
*td
= tc
->td
;
1553 struct dm_thin_lookup_result result
;
1555 map_context
->ptr
= thin_hook_bio(tc
, bio
);
1556 if (bio
->bi_rw
& (REQ_DISCARD
| REQ_FLUSH
| REQ_FUA
)) {
1557 thin_defer_bio(tc
, bio
);
1558 return DM_MAPIO_SUBMITTED
;
1561 r
= dm_thin_find_block(td
, block
, 0, &result
);
1564 * Note that we defer readahead too.
1568 if (unlikely(result
.shared
)) {
1570 * We have a race condition here between the
1571 * result.shared value returned by the lookup and
1572 * snapshot creation, which may cause new
1575 * To avoid this always quiesce the origin before
1576 * taking the snap. You want to do this anyway to
1577 * ensure a consistent application view
1580 * More distant ancestors are irrelevant. The
1581 * shared flag will be set in their case.
1583 thin_defer_bio(tc
, bio
);
1584 r
= DM_MAPIO_SUBMITTED
;
1586 remap(tc
, bio
, result
.block
);
1587 r
= DM_MAPIO_REMAPPED
;
1593 * In future, the failed dm_thin_find_block above could
1594 * provide the hint to load the metadata into cache.
1597 thin_defer_bio(tc
, bio
);
1598 r
= DM_MAPIO_SUBMITTED
;
1605 static int pool_is_congested(struct dm_target_callbacks
*cb
, int bdi_bits
)
1608 unsigned long flags
;
1609 struct pool_c
*pt
= container_of(cb
, struct pool_c
, callbacks
);
1611 spin_lock_irqsave(&pt
->pool
->lock
, flags
);
1612 r
= !bio_list_empty(&pt
->pool
->retry_on_resume_list
);
1613 spin_unlock_irqrestore(&pt
->pool
->lock
, flags
);
1616 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1617 r
= bdi_congested(&q
->backing_dev_info
, bdi_bits
);
1623 static void __requeue_bios(struct pool
*pool
)
1625 bio_list_merge(&pool
->deferred_bios
, &pool
->retry_on_resume_list
);
1626 bio_list_init(&pool
->retry_on_resume_list
);
1629 /*----------------------------------------------------------------
1630 * Binding of control targets to a pool object
1631 *--------------------------------------------------------------*/
1632 static int bind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1634 struct pool_c
*pt
= ti
->private;
1637 pool
->low_water_blocks
= pt
->low_water_blocks
;
1641 * If discard_passdown was enabled verify that the data device
1642 * supports discards. Disable discard_passdown if not; otherwise
1643 * -EOPNOTSUPP will be returned.
1645 if (pt
->pf
.discard_passdown
) {
1646 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1647 if (!q
|| !blk_queue_discard(q
)) {
1648 char buf
[BDEVNAME_SIZE
];
1649 DMWARN("Discard unsupported by data device (%s): Disabling discard passdown.",
1650 bdevname(pt
->data_dev
->bdev
, buf
));
1651 pool
->pf
.discard_passdown
= 0;
1658 static void unbind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1664 /*----------------------------------------------------------------
1666 *--------------------------------------------------------------*/
1667 /* Initialize pool features. */
1668 static void pool_features_init(struct pool_features
*pf
)
1670 pf
->zero_new_blocks
= 1;
1671 pf
->discard_enabled
= 1;
1672 pf
->discard_passdown
= 1;
1675 static void __pool_destroy(struct pool
*pool
)
1677 __pool_table_remove(pool
);
1679 if (dm_pool_metadata_close(pool
->pmd
) < 0)
1680 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1682 prison_destroy(pool
->prison
);
1683 dm_kcopyd_client_destroy(pool
->copier
);
1686 destroy_workqueue(pool
->wq
);
1688 if (pool
->next_mapping
)
1689 mempool_free(pool
->next_mapping
, pool
->mapping_pool
);
1690 mempool_destroy(pool
->mapping_pool
);
1691 mempool_destroy(pool
->endio_hook_pool
);
1695 static struct kmem_cache
*_new_mapping_cache
;
1696 static struct kmem_cache
*_endio_hook_cache
;
1698 static struct pool
*pool_create(struct mapped_device
*pool_md
,
1699 struct block_device
*metadata_dev
,
1700 unsigned long block_size
, char **error
)
1705 struct dm_pool_metadata
*pmd
;
1707 pmd
= dm_pool_metadata_open(metadata_dev
, block_size
);
1709 *error
= "Error creating metadata object";
1710 return (struct pool
*)pmd
;
1713 pool
= kmalloc(sizeof(*pool
), GFP_KERNEL
);
1715 *error
= "Error allocating memory for pool";
1716 err_p
= ERR_PTR(-ENOMEM
);
1721 pool
->sectors_per_block
= block_size
;
1722 pool
->block_shift
= ffs(block_size
) - 1;
1723 pool
->offset_mask
= block_size
- 1;
1724 pool
->low_water_blocks
= 0;
1725 pool_features_init(&pool
->pf
);
1726 pool
->prison
= prison_create(PRISON_CELLS
);
1727 if (!pool
->prison
) {
1728 *error
= "Error creating pool's bio prison";
1729 err_p
= ERR_PTR(-ENOMEM
);
1733 pool
->copier
= dm_kcopyd_client_create();
1734 if (IS_ERR(pool
->copier
)) {
1735 r
= PTR_ERR(pool
->copier
);
1736 *error
= "Error creating pool's kcopyd client";
1738 goto bad_kcopyd_client
;
1742 * Create singlethreaded workqueue that will service all devices
1743 * that use this metadata.
1745 pool
->wq
= alloc_ordered_workqueue("dm-" DM_MSG_PREFIX
, WQ_MEM_RECLAIM
);
1747 *error
= "Error creating pool's workqueue";
1748 err_p
= ERR_PTR(-ENOMEM
);
1752 INIT_WORK(&pool
->worker
, do_worker
);
1753 INIT_DELAYED_WORK(&pool
->waker
, do_waker
);
1754 spin_lock_init(&pool
->lock
);
1755 bio_list_init(&pool
->deferred_bios
);
1756 bio_list_init(&pool
->deferred_flush_bios
);
1757 INIT_LIST_HEAD(&pool
->prepared_mappings
);
1758 INIT_LIST_HEAD(&pool
->prepared_discards
);
1759 pool
->low_water_triggered
= 0;
1760 pool
->no_free_space
= 0;
1761 bio_list_init(&pool
->retry_on_resume_list
);
1762 ds_init(&pool
->shared_read_ds
);
1763 ds_init(&pool
->all_io_ds
);
1765 pool
->next_mapping
= NULL
;
1766 pool
->mapping_pool
= mempool_create_slab_pool(MAPPING_POOL_SIZE
,
1767 _new_mapping_cache
);
1768 if (!pool
->mapping_pool
) {
1769 *error
= "Error creating pool's mapping mempool";
1770 err_p
= ERR_PTR(-ENOMEM
);
1771 goto bad_mapping_pool
;
1774 pool
->endio_hook_pool
= mempool_create_slab_pool(ENDIO_HOOK_POOL_SIZE
,
1776 if (!pool
->endio_hook_pool
) {
1777 *error
= "Error creating pool's endio_hook mempool";
1778 err_p
= ERR_PTR(-ENOMEM
);
1779 goto bad_endio_hook_pool
;
1781 pool
->ref_count
= 1;
1782 pool
->last_commit_jiffies
= jiffies
;
1783 pool
->pool_md
= pool_md
;
1784 pool
->md_dev
= metadata_dev
;
1785 __pool_table_insert(pool
);
1789 bad_endio_hook_pool
:
1790 mempool_destroy(pool
->mapping_pool
);
1792 destroy_workqueue(pool
->wq
);
1794 dm_kcopyd_client_destroy(pool
->copier
);
1796 prison_destroy(pool
->prison
);
1800 if (dm_pool_metadata_close(pmd
))
1801 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1806 static void __pool_inc(struct pool
*pool
)
1808 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1812 static void __pool_dec(struct pool
*pool
)
1814 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1815 BUG_ON(!pool
->ref_count
);
1816 if (!--pool
->ref_count
)
1817 __pool_destroy(pool
);
1820 static struct pool
*__pool_find(struct mapped_device
*pool_md
,
1821 struct block_device
*metadata_dev
,
1822 unsigned long block_size
, char **error
,
1825 struct pool
*pool
= __pool_table_lookup_metadata_dev(metadata_dev
);
1828 if (pool
->pool_md
!= pool_md
)
1829 return ERR_PTR(-EBUSY
);
1833 pool
= __pool_table_lookup(pool_md
);
1835 if (pool
->md_dev
!= metadata_dev
)
1836 return ERR_PTR(-EINVAL
);
1840 pool
= pool_create(pool_md
, metadata_dev
, block_size
, error
);
1848 /*----------------------------------------------------------------
1849 * Pool target methods
1850 *--------------------------------------------------------------*/
1851 static void pool_dtr(struct dm_target
*ti
)
1853 struct pool_c
*pt
= ti
->private;
1855 mutex_lock(&dm_thin_pool_table
.mutex
);
1857 unbind_control_target(pt
->pool
, ti
);
1858 __pool_dec(pt
->pool
);
1859 dm_put_device(ti
, pt
->metadata_dev
);
1860 dm_put_device(ti
, pt
->data_dev
);
1863 mutex_unlock(&dm_thin_pool_table
.mutex
);
1866 static int parse_pool_features(struct dm_arg_set
*as
, struct pool_features
*pf
,
1867 struct dm_target
*ti
)
1871 const char *arg_name
;
1873 static struct dm_arg _args
[] = {
1874 {0, 3, "Invalid number of pool feature arguments"},
1878 * No feature arguments supplied.
1883 r
= dm_read_arg_group(_args
, as
, &argc
, &ti
->error
);
1887 while (argc
&& !r
) {
1888 arg_name
= dm_shift_arg(as
);
1891 if (!strcasecmp(arg_name
, "skip_block_zeroing")) {
1892 pf
->zero_new_blocks
= 0;
1894 } else if (!strcasecmp(arg_name
, "ignore_discard")) {
1895 pf
->discard_enabled
= 0;
1897 } else if (!strcasecmp(arg_name
, "no_discard_passdown")) {
1898 pf
->discard_passdown
= 0;
1902 ti
->error
= "Unrecognised pool feature requested";
1910 * thin-pool <metadata dev> <data dev>
1911 * <data block size (sectors)>
1912 * <low water mark (blocks)>
1913 * [<#feature args> [<arg>]*]
1915 * Optional feature arguments are:
1916 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1917 * ignore_discard: disable discard
1918 * no_discard_passdown: don't pass discards down to the data device
1920 static int pool_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
1922 int r
, pool_created
= 0;
1925 struct pool_features pf
;
1926 struct dm_arg_set as
;
1927 struct dm_dev
*data_dev
;
1928 unsigned long block_size
;
1929 dm_block_t low_water_blocks
;
1930 struct dm_dev
*metadata_dev
;
1931 sector_t metadata_dev_size
;
1932 char b
[BDEVNAME_SIZE
];
1935 * FIXME Remove validation from scope of lock.
1937 mutex_lock(&dm_thin_pool_table
.mutex
);
1940 ti
->error
= "Invalid argument count";
1947 r
= dm_get_device(ti
, argv
[0], FMODE_READ
| FMODE_WRITE
, &metadata_dev
);
1949 ti
->error
= "Error opening metadata block device";
1953 metadata_dev_size
= i_size_read(metadata_dev
->bdev
->bd_inode
) >> SECTOR_SHIFT
;
1954 if (metadata_dev_size
> THIN_METADATA_MAX_SECTORS_WARNING
)
1955 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1956 bdevname(metadata_dev
->bdev
, b
), THIN_METADATA_MAX_SECTORS
);
1958 r
= dm_get_device(ti
, argv
[1], FMODE_READ
| FMODE_WRITE
, &data_dev
);
1960 ti
->error
= "Error getting data device";
1964 if (kstrtoul(argv
[2], 10, &block_size
) || !block_size
||
1965 block_size
< DATA_DEV_BLOCK_SIZE_MIN_SECTORS
||
1966 block_size
> DATA_DEV_BLOCK_SIZE_MAX_SECTORS
||
1967 !is_power_of_2(block_size
)) {
1968 ti
->error
= "Invalid block size";
1973 if (kstrtoull(argv
[3], 10, (unsigned long long *)&low_water_blocks
)) {
1974 ti
->error
= "Invalid low water mark";
1980 * Set default pool features.
1982 pool_features_init(&pf
);
1984 dm_consume_args(&as
, 4);
1985 r
= parse_pool_features(&as
, &pf
, ti
);
1989 pt
= kzalloc(sizeof(*pt
), GFP_KERNEL
);
1995 pool
= __pool_find(dm_table_get_md(ti
->table
), metadata_dev
->bdev
,
1996 block_size
, &ti
->error
, &pool_created
);
2003 * 'pool_created' reflects whether this is the first table load.
2004 * Top level discard support is not allowed to be changed after
2005 * initial load. This would require a pool reload to trigger thin
2008 if (!pool_created
&& pf
.discard_enabled
!= pool
->pf
.discard_enabled
) {
2009 ti
->error
= "Discard support cannot be disabled once enabled";
2011 goto out_flags_changed
;
2016 pt
->metadata_dev
= metadata_dev
;
2017 pt
->data_dev
= data_dev
;
2018 pt
->low_water_blocks
= low_water_blocks
;
2020 ti
->num_flush_requests
= 1;
2022 * Only need to enable discards if the pool should pass
2023 * them down to the data device. The thin device's discard
2024 * processing will cause mappings to be removed from the btree.
2026 if (pf
.discard_enabled
&& pf
.discard_passdown
) {
2027 ti
->num_discard_requests
= 1;
2029 * Setting 'discards_supported' circumvents the normal
2030 * stacking of discard limits (this keeps the pool and
2031 * thin devices' discard limits consistent).
2033 ti
->discards_supported
= 1;
2037 pt
->callbacks
.congested_fn
= pool_is_congested
;
2038 dm_table_add_target_callbacks(ti
->table
, &pt
->callbacks
);
2040 mutex_unlock(&dm_thin_pool_table
.mutex
);
2049 dm_put_device(ti
, data_dev
);
2051 dm_put_device(ti
, metadata_dev
);
2053 mutex_unlock(&dm_thin_pool_table
.mutex
);
2058 static int pool_map(struct dm_target
*ti
, struct bio
*bio
,
2059 union map_info
*map_context
)
2062 struct pool_c
*pt
= ti
->private;
2063 struct pool
*pool
= pt
->pool
;
2064 unsigned long flags
;
2067 * As this is a singleton target, ti->begin is always zero.
2069 spin_lock_irqsave(&pool
->lock
, flags
);
2070 bio
->bi_bdev
= pt
->data_dev
->bdev
;
2071 r
= DM_MAPIO_REMAPPED
;
2072 spin_unlock_irqrestore(&pool
->lock
, flags
);
2078 * Retrieves the number of blocks of the data device from
2079 * the superblock and compares it to the actual device size,
2080 * thus resizing the data device in case it has grown.
2082 * This both copes with opening preallocated data devices in the ctr
2083 * being followed by a resume
2085 * calling the resume method individually after userspace has
2086 * grown the data device in reaction to a table event.
2088 static int pool_preresume(struct dm_target
*ti
)
2091 struct pool_c
*pt
= ti
->private;
2092 struct pool
*pool
= pt
->pool
;
2093 dm_block_t data_size
, sb_data_size
;
2096 * Take control of the pool object.
2098 r
= bind_control_target(pool
, ti
);
2102 data_size
= ti
->len
>> pool
->block_shift
;
2103 r
= dm_pool_get_data_dev_size(pool
->pmd
, &sb_data_size
);
2105 DMERR("failed to retrieve data device size");
2109 if (data_size
< sb_data_size
) {
2110 DMERR("pool target too small, is %llu blocks (expected %llu)",
2111 data_size
, sb_data_size
);
2114 } else if (data_size
> sb_data_size
) {
2115 r
= dm_pool_resize_data_dev(pool
->pmd
, data_size
);
2117 DMERR("failed to resize data device");
2121 r
= dm_pool_commit_metadata(pool
->pmd
);
2123 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2132 static void pool_resume(struct dm_target
*ti
)
2134 struct pool_c
*pt
= ti
->private;
2135 struct pool
*pool
= pt
->pool
;
2136 unsigned long flags
;
2138 spin_lock_irqsave(&pool
->lock
, flags
);
2139 pool
->low_water_triggered
= 0;
2140 pool
->no_free_space
= 0;
2141 __requeue_bios(pool
);
2142 spin_unlock_irqrestore(&pool
->lock
, flags
);
2144 do_waker(&pool
->waker
.work
);
2147 static void pool_postsuspend(struct dm_target
*ti
)
2150 struct pool_c
*pt
= ti
->private;
2151 struct pool
*pool
= pt
->pool
;
2153 cancel_delayed_work(&pool
->waker
);
2154 flush_workqueue(pool
->wq
);
2156 r
= dm_pool_commit_metadata(pool
->pmd
);
2158 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2160 /* FIXME: invalidate device? error the next FUA or FLUSH bio ?*/
2164 static int check_arg_count(unsigned argc
, unsigned args_required
)
2166 if (argc
!= args_required
) {
2167 DMWARN("Message received with %u arguments instead of %u.",
2168 argc
, args_required
);
2175 static int read_dev_id(char *arg
, dm_thin_id
*dev_id
, int warning
)
2177 if (!kstrtoull(arg
, 10, (unsigned long long *)dev_id
) &&
2178 *dev_id
<= MAX_DEV_ID
)
2182 DMWARN("Message received with invalid device id: %s", arg
);
2187 static int process_create_thin_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2192 r
= check_arg_count(argc
, 2);
2196 r
= read_dev_id(argv
[1], &dev_id
, 1);
2200 r
= dm_pool_create_thin(pool
->pmd
, dev_id
);
2202 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2210 static int process_create_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2213 dm_thin_id origin_dev_id
;
2216 r
= check_arg_count(argc
, 3);
2220 r
= read_dev_id(argv
[1], &dev_id
, 1);
2224 r
= read_dev_id(argv
[2], &origin_dev_id
, 1);
2228 r
= dm_pool_create_snap(pool
->pmd
, dev_id
, origin_dev_id
);
2230 DMWARN("Creation of new snapshot %s of device %s failed.",
2238 static int process_delete_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2243 r
= check_arg_count(argc
, 2);
2247 r
= read_dev_id(argv
[1], &dev_id
, 1);
2251 r
= dm_pool_delete_thin_device(pool
->pmd
, dev_id
);
2253 DMWARN("Deletion of thin device %s failed.", argv
[1]);
2258 static int process_set_transaction_id_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2260 dm_thin_id old_id
, new_id
;
2263 r
= check_arg_count(argc
, 3);
2267 if (kstrtoull(argv
[1], 10, (unsigned long long *)&old_id
)) {
2268 DMWARN("set_transaction_id message: Unrecognised id %s.", argv
[1]);
2272 if (kstrtoull(argv
[2], 10, (unsigned long long *)&new_id
)) {
2273 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv
[2]);
2277 r
= dm_pool_set_metadata_transaction_id(pool
->pmd
, old_id
, new_id
);
2279 DMWARN("Failed to change transaction id from %s to %s.",
2287 static int process_reserve_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2291 r
= check_arg_count(argc
, 1);
2295 r
= dm_pool_commit_metadata(pool
->pmd
);
2297 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2302 r
= dm_pool_reserve_metadata_snap(pool
->pmd
);
2304 DMWARN("reserve_metadata_snap message failed.");
2309 static int process_release_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2313 r
= check_arg_count(argc
, 1);
2317 r
= dm_pool_release_metadata_snap(pool
->pmd
);
2319 DMWARN("release_metadata_snap message failed.");
2325 * Messages supported:
2326 * create_thin <dev_id>
2327 * create_snap <dev_id> <origin_id>
2329 * trim <dev_id> <new_size_in_sectors>
2330 * set_transaction_id <current_trans_id> <new_trans_id>
2331 * reserve_metadata_snap
2332 * release_metadata_snap
2334 static int pool_message(struct dm_target
*ti
, unsigned argc
, char **argv
)
2337 struct pool_c
*pt
= ti
->private;
2338 struct pool
*pool
= pt
->pool
;
2340 if (!strcasecmp(argv
[0], "create_thin"))
2341 r
= process_create_thin_mesg(argc
, argv
, pool
);
2343 else if (!strcasecmp(argv
[0], "create_snap"))
2344 r
= process_create_snap_mesg(argc
, argv
, pool
);
2346 else if (!strcasecmp(argv
[0], "delete"))
2347 r
= process_delete_mesg(argc
, argv
, pool
);
2349 else if (!strcasecmp(argv
[0], "set_transaction_id"))
2350 r
= process_set_transaction_id_mesg(argc
, argv
, pool
);
2352 else if (!strcasecmp(argv
[0], "reserve_metadata_snap"))
2353 r
= process_reserve_metadata_snap_mesg(argc
, argv
, pool
);
2355 else if (!strcasecmp(argv
[0], "release_metadata_snap"))
2356 r
= process_release_metadata_snap_mesg(argc
, argv
, pool
);
2359 DMWARN("Unrecognised thin pool target message received: %s", argv
[0]);
2362 r
= dm_pool_commit_metadata(pool
->pmd
);
2364 DMERR("%s message: dm_pool_commit_metadata() failed, error = %d",
2373 * <transaction id> <used metadata sectors>/<total metadata sectors>
2374 * <used data sectors>/<total data sectors> <held metadata root>
2376 static int pool_status(struct dm_target
*ti
, status_type_t type
,
2377 char *result
, unsigned maxlen
)
2381 uint64_t transaction_id
;
2382 dm_block_t nr_free_blocks_data
;
2383 dm_block_t nr_free_blocks_metadata
;
2384 dm_block_t nr_blocks_data
;
2385 dm_block_t nr_blocks_metadata
;
2386 dm_block_t held_root
;
2387 char buf
[BDEVNAME_SIZE
];
2388 char buf2
[BDEVNAME_SIZE
];
2389 struct pool_c
*pt
= ti
->private;
2390 struct pool
*pool
= pt
->pool
;
2393 case STATUSTYPE_INFO
:
2394 r
= dm_pool_get_metadata_transaction_id(pool
->pmd
,
2399 r
= dm_pool_get_free_metadata_block_count(pool
->pmd
,
2400 &nr_free_blocks_metadata
);
2404 r
= dm_pool_get_metadata_dev_size(pool
->pmd
, &nr_blocks_metadata
);
2408 r
= dm_pool_get_free_block_count(pool
->pmd
,
2409 &nr_free_blocks_data
);
2413 r
= dm_pool_get_data_dev_size(pool
->pmd
, &nr_blocks_data
);
2417 r
= dm_pool_get_metadata_snap(pool
->pmd
, &held_root
);
2421 DMEMIT("%llu %llu/%llu %llu/%llu ",
2422 (unsigned long long)transaction_id
,
2423 (unsigned long long)(nr_blocks_metadata
- nr_free_blocks_metadata
),
2424 (unsigned long long)nr_blocks_metadata
,
2425 (unsigned long long)(nr_blocks_data
- nr_free_blocks_data
),
2426 (unsigned long long)nr_blocks_data
);
2429 DMEMIT("%llu", held_root
);
2435 case STATUSTYPE_TABLE
:
2436 DMEMIT("%s %s %lu %llu ",
2437 format_dev_t(buf
, pt
->metadata_dev
->bdev
->bd_dev
),
2438 format_dev_t(buf2
, pt
->data_dev
->bdev
->bd_dev
),
2439 (unsigned long)pool
->sectors_per_block
,
2440 (unsigned long long)pt
->low_water_blocks
);
2442 count
= !pool
->pf
.zero_new_blocks
+ !pool
->pf
.discard_enabled
+
2443 !pt
->pf
.discard_passdown
;
2444 DMEMIT("%u ", count
);
2446 if (!pool
->pf
.zero_new_blocks
)
2447 DMEMIT("skip_block_zeroing ");
2449 if (!pool
->pf
.discard_enabled
)
2450 DMEMIT("ignore_discard ");
2452 if (!pt
->pf
.discard_passdown
)
2453 DMEMIT("no_discard_passdown ");
2461 static int pool_iterate_devices(struct dm_target
*ti
,
2462 iterate_devices_callout_fn fn
, void *data
)
2464 struct pool_c
*pt
= ti
->private;
2466 return fn(ti
, pt
->data_dev
, 0, ti
->len
, data
);
2469 static int pool_merge(struct dm_target
*ti
, struct bvec_merge_data
*bvm
,
2470 struct bio_vec
*biovec
, int max_size
)
2472 struct pool_c
*pt
= ti
->private;
2473 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
2475 if (!q
->merge_bvec_fn
)
2478 bvm
->bi_bdev
= pt
->data_dev
->bdev
;
2480 return min(max_size
, q
->merge_bvec_fn(q
, bvm
, biovec
));
2483 static void set_discard_limits(struct pool
*pool
, struct queue_limits
*limits
)
2486 * FIXME: these limits may be incompatible with the pool's data device
2488 limits
->max_discard_sectors
= pool
->sectors_per_block
;
2491 * This is just a hint, and not enforced. We have to cope with
2492 * bios that overlap 2 blocks.
2494 limits
->discard_granularity
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
2495 limits
->discard_zeroes_data
= pool
->pf
.zero_new_blocks
;
2498 static void pool_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
2500 struct pool_c
*pt
= ti
->private;
2501 struct pool
*pool
= pt
->pool
;
2503 blk_limits_io_min(limits
, 0);
2504 blk_limits_io_opt(limits
, pool
->sectors_per_block
<< SECTOR_SHIFT
);
2505 if (pool
->pf
.discard_enabled
)
2506 set_discard_limits(pool
, limits
);
2509 static struct target_type pool_target
= {
2510 .name
= "thin-pool",
2511 .features
= DM_TARGET_SINGLETON
| DM_TARGET_ALWAYS_WRITEABLE
|
2512 DM_TARGET_IMMUTABLE
,
2513 .version
= {1, 2, 0},
2514 .module
= THIS_MODULE
,
2518 .postsuspend
= pool_postsuspend
,
2519 .preresume
= pool_preresume
,
2520 .resume
= pool_resume
,
2521 .message
= pool_message
,
2522 .status
= pool_status
,
2523 .merge
= pool_merge
,
2524 .iterate_devices
= pool_iterate_devices
,
2525 .io_hints
= pool_io_hints
,
2528 /*----------------------------------------------------------------
2529 * Thin target methods
2530 *--------------------------------------------------------------*/
2531 static void thin_dtr(struct dm_target
*ti
)
2533 struct thin_c
*tc
= ti
->private;
2535 mutex_lock(&dm_thin_pool_table
.mutex
);
2537 __pool_dec(tc
->pool
);
2538 dm_pool_close_thin_device(tc
->td
);
2539 dm_put_device(ti
, tc
->pool_dev
);
2541 dm_put_device(ti
, tc
->origin_dev
);
2544 mutex_unlock(&dm_thin_pool_table
.mutex
);
2548 * Thin target parameters:
2550 * <pool_dev> <dev_id> [origin_dev]
2552 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2553 * dev_id: the internal device identifier
2554 * origin_dev: a device external to the pool that should act as the origin
2556 * If the pool device has discards disabled, they get disabled for the thin
2559 static int thin_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
2563 struct dm_dev
*pool_dev
, *origin_dev
;
2564 struct mapped_device
*pool_md
;
2566 mutex_lock(&dm_thin_pool_table
.mutex
);
2568 if (argc
!= 2 && argc
!= 3) {
2569 ti
->error
= "Invalid argument count";
2574 tc
= ti
->private = kzalloc(sizeof(*tc
), GFP_KERNEL
);
2576 ti
->error
= "Out of memory";
2582 r
= dm_get_device(ti
, argv
[2], FMODE_READ
, &origin_dev
);
2584 ti
->error
= "Error opening origin device";
2585 goto bad_origin_dev
;
2587 tc
->origin_dev
= origin_dev
;
2590 r
= dm_get_device(ti
, argv
[0], dm_table_get_mode(ti
->table
), &pool_dev
);
2592 ti
->error
= "Error opening pool device";
2595 tc
->pool_dev
= pool_dev
;
2597 if (read_dev_id(argv
[1], (unsigned long long *)&tc
->dev_id
, 0)) {
2598 ti
->error
= "Invalid device id";
2603 pool_md
= dm_get_md(tc
->pool_dev
->bdev
->bd_dev
);
2605 ti
->error
= "Couldn't get pool mapped device";
2610 tc
->pool
= __pool_table_lookup(pool_md
);
2612 ti
->error
= "Couldn't find pool object";
2614 goto bad_pool_lookup
;
2616 __pool_inc(tc
->pool
);
2618 r
= dm_pool_open_thin_device(tc
->pool
->pmd
, tc
->dev_id
, &tc
->td
);
2620 ti
->error
= "Couldn't open thin internal device";
2624 ti
->split_io
= tc
->pool
->sectors_per_block
;
2625 ti
->num_flush_requests
= 1;
2627 /* In case the pool supports discards, pass them on. */
2628 if (tc
->pool
->pf
.discard_enabled
) {
2629 ti
->discards_supported
= 1;
2630 ti
->num_discard_requests
= 1;
2635 mutex_unlock(&dm_thin_pool_table
.mutex
);
2640 __pool_dec(tc
->pool
);
2644 dm_put_device(ti
, tc
->pool_dev
);
2647 dm_put_device(ti
, tc
->origin_dev
);
2651 mutex_unlock(&dm_thin_pool_table
.mutex
);
2656 static int thin_map(struct dm_target
*ti
, struct bio
*bio
,
2657 union map_info
*map_context
)
2659 bio
->bi_sector
= dm_target_offset(ti
, bio
->bi_sector
);
2661 return thin_bio_map(ti
, bio
, map_context
);
2664 static int thin_endio(struct dm_target
*ti
,
2665 struct bio
*bio
, int err
,
2666 union map_info
*map_context
)
2668 unsigned long flags
;
2669 struct dm_thin_endio_hook
*h
= map_context
->ptr
;
2670 struct list_head work
;
2671 struct dm_thin_new_mapping
*m
, *tmp
;
2672 struct pool
*pool
= h
->tc
->pool
;
2674 if (h
->shared_read_entry
) {
2675 INIT_LIST_HEAD(&work
);
2676 ds_dec(h
->shared_read_entry
, &work
);
2678 spin_lock_irqsave(&pool
->lock
, flags
);
2679 list_for_each_entry_safe(m
, tmp
, &work
, list
) {
2682 __maybe_add_mapping(m
);
2684 spin_unlock_irqrestore(&pool
->lock
, flags
);
2687 if (h
->all_io_entry
) {
2688 INIT_LIST_HEAD(&work
);
2689 ds_dec(h
->all_io_entry
, &work
);
2690 spin_lock_irqsave(&pool
->lock
, flags
);
2691 list_for_each_entry_safe(m
, tmp
, &work
, list
)
2692 list_add(&m
->list
, &pool
->prepared_discards
);
2693 spin_unlock_irqrestore(&pool
->lock
, flags
);
2696 mempool_free(h
, pool
->endio_hook_pool
);
2701 static void thin_postsuspend(struct dm_target
*ti
)
2703 if (dm_noflush_suspending(ti
))
2704 requeue_io((struct thin_c
*)ti
->private);
2708 * <nr mapped sectors> <highest mapped sector>
2710 static int thin_status(struct dm_target
*ti
, status_type_t type
,
2711 char *result
, unsigned maxlen
)
2715 dm_block_t mapped
, highest
;
2716 char buf
[BDEVNAME_SIZE
];
2717 struct thin_c
*tc
= ti
->private;
2723 case STATUSTYPE_INFO
:
2724 r
= dm_thin_get_mapped_count(tc
->td
, &mapped
);
2728 r
= dm_thin_get_highest_mapped_block(tc
->td
, &highest
);
2732 DMEMIT("%llu ", mapped
* tc
->pool
->sectors_per_block
);
2734 DMEMIT("%llu", ((highest
+ 1) *
2735 tc
->pool
->sectors_per_block
) - 1);
2740 case STATUSTYPE_TABLE
:
2742 format_dev_t(buf
, tc
->pool_dev
->bdev
->bd_dev
),
2743 (unsigned long) tc
->dev_id
);
2745 DMEMIT(" %s", format_dev_t(buf
, tc
->origin_dev
->bdev
->bd_dev
));
2753 static int thin_iterate_devices(struct dm_target
*ti
,
2754 iterate_devices_callout_fn fn
, void *data
)
2757 struct thin_c
*tc
= ti
->private;
2760 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2761 * we follow a more convoluted path through to the pool's target.
2764 return 0; /* nothing is bound */
2766 blocks
= tc
->pool
->ti
->len
>> tc
->pool
->block_shift
;
2768 return fn(ti
, tc
->pool_dev
, 0, tc
->pool
->sectors_per_block
* blocks
, data
);
2773 static void thin_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
2775 struct thin_c
*tc
= ti
->private;
2776 struct pool
*pool
= tc
->pool
;
2778 blk_limits_io_min(limits
, 0);
2779 blk_limits_io_opt(limits
, pool
->sectors_per_block
<< SECTOR_SHIFT
);
2780 set_discard_limits(pool
, limits
);
2783 static struct target_type thin_target
= {
2785 .version
= {1, 1, 0},
2786 .module
= THIS_MODULE
,
2790 .end_io
= thin_endio
,
2791 .postsuspend
= thin_postsuspend
,
2792 .status
= thin_status
,
2793 .iterate_devices
= thin_iterate_devices
,
2794 .io_hints
= thin_io_hints
,
2797 /*----------------------------------------------------------------*/
2799 static int __init
dm_thin_init(void)
2805 r
= dm_register_target(&thin_target
);
2809 r
= dm_register_target(&pool_target
);
2811 goto bad_pool_target
;
2815 _cell_cache
= KMEM_CACHE(dm_bio_prison_cell
, 0);
2817 goto bad_cell_cache
;
2819 _new_mapping_cache
= KMEM_CACHE(dm_thin_new_mapping
, 0);
2820 if (!_new_mapping_cache
)
2821 goto bad_new_mapping_cache
;
2823 _endio_hook_cache
= KMEM_CACHE(dm_thin_endio_hook
, 0);
2824 if (!_endio_hook_cache
)
2825 goto bad_endio_hook_cache
;
2829 bad_endio_hook_cache
:
2830 kmem_cache_destroy(_new_mapping_cache
);
2831 bad_new_mapping_cache
:
2832 kmem_cache_destroy(_cell_cache
);
2834 dm_unregister_target(&pool_target
);
2836 dm_unregister_target(&thin_target
);
2841 static void dm_thin_exit(void)
2843 dm_unregister_target(&thin_target
);
2844 dm_unregister_target(&pool_target
);
2846 kmem_cache_destroy(_cell_cache
);
2847 kmem_cache_destroy(_new_mapping_cache
);
2848 kmem_cache_destroy(_endio_hook_cache
);
2851 module_init(dm_thin_init
);
2852 module_exit(dm_thin_exit
);
2854 MODULE_DESCRIPTION(DM_NAME
" thin provisioning target");
2855 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2856 MODULE_LICENSE("GPL");