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 if ((!lookup_result
.shared
) && pool
->pf
.discard_passdown
)
1249 remap_and_issue(tc
, bio
, lookup_result
.block
);
1257 * It isn't provisioned, just forget it.
1259 cell_release_singleton(cell
, bio
);
1264 DMERR("discard: find block unexpectedly returned %d", r
);
1265 cell_release_singleton(cell
, bio
);
1271 static void break_sharing(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1272 struct cell_key
*key
,
1273 struct dm_thin_lookup_result
*lookup_result
,
1274 struct dm_bio_prison_cell
*cell
)
1277 dm_block_t data_block
;
1279 r
= alloc_data_block(tc
, &data_block
);
1282 schedule_internal_copy(tc
, block
, lookup_result
->block
,
1283 data_block
, cell
, bio
);
1291 DMERR("%s: alloc_data_block() failed, error = %d", __func__
, r
);
1297 static void process_shared_bio(struct thin_c
*tc
, struct bio
*bio
,
1299 struct dm_thin_lookup_result
*lookup_result
)
1301 struct dm_bio_prison_cell
*cell
;
1302 struct pool
*pool
= tc
->pool
;
1303 struct cell_key key
;
1306 * If cell is already occupied, then sharing is already in the process
1307 * of being broken so we have nothing further to do here.
1309 build_data_key(tc
->td
, lookup_result
->block
, &key
);
1310 if (bio_detain(pool
->prison
, &key
, bio
, &cell
))
1313 if (bio_data_dir(bio
) == WRITE
)
1314 break_sharing(tc
, bio
, block
, &key
, lookup_result
, cell
);
1316 struct dm_thin_endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1318 h
->shared_read_entry
= ds_inc(&pool
->shared_read_ds
);
1320 cell_release_singleton(cell
, bio
);
1321 remap_and_issue(tc
, bio
, lookup_result
->block
);
1325 static void provision_block(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1326 struct dm_bio_prison_cell
*cell
)
1329 dm_block_t data_block
;
1332 * Remap empty bios (flushes) immediately, without provisioning.
1334 if (!bio
->bi_size
) {
1335 cell_release_singleton(cell
, bio
);
1336 remap_and_issue(tc
, bio
, 0);
1341 * Fill read bios with zeroes and complete them immediately.
1343 if (bio_data_dir(bio
) == READ
) {
1345 cell_release_singleton(cell
, bio
);
1350 r
= alloc_data_block(tc
, &data_block
);
1354 schedule_external_copy(tc
, block
, data_block
, cell
, bio
);
1356 schedule_zero(tc
, block
, data_block
, cell
, bio
);
1364 DMERR("%s: alloc_data_block() failed, error = %d", __func__
, r
);
1370 static void process_bio(struct thin_c
*tc
, struct bio
*bio
)
1373 dm_block_t block
= get_bio_block(tc
, bio
);
1374 struct dm_bio_prison_cell
*cell
;
1375 struct cell_key key
;
1376 struct dm_thin_lookup_result lookup_result
;
1379 * If cell is already occupied, then the block is already
1380 * being provisioned so we have nothing further to do here.
1382 build_virtual_key(tc
->td
, block
, &key
);
1383 if (bio_detain(tc
->pool
->prison
, &key
, bio
, &cell
))
1386 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1390 * We can release this cell now. This thread is the only
1391 * one that puts bios into a cell, and we know there were
1392 * no preceding bios.
1395 * TODO: this will probably have to change when discard goes
1398 cell_release_singleton(cell
, bio
);
1400 if (lookup_result
.shared
)
1401 process_shared_bio(tc
, bio
, block
, &lookup_result
);
1403 remap_and_issue(tc
, bio
, lookup_result
.block
);
1407 if (bio_data_dir(bio
) == READ
&& tc
->origin_dev
) {
1408 cell_release_singleton(cell
, bio
);
1409 remap_to_origin_and_issue(tc
, bio
);
1411 provision_block(tc
, bio
, block
, cell
);
1415 DMERR("dm_thin_find_block() failed, error = %d", r
);
1416 cell_release_singleton(cell
, bio
);
1422 static int need_commit_due_to_time(struct pool
*pool
)
1424 return jiffies
< pool
->last_commit_jiffies
||
1425 jiffies
> pool
->last_commit_jiffies
+ COMMIT_PERIOD
;
1428 static void process_deferred_bios(struct pool
*pool
)
1430 unsigned long flags
;
1432 struct bio_list bios
;
1435 bio_list_init(&bios
);
1437 spin_lock_irqsave(&pool
->lock
, flags
);
1438 bio_list_merge(&bios
, &pool
->deferred_bios
);
1439 bio_list_init(&pool
->deferred_bios
);
1440 spin_unlock_irqrestore(&pool
->lock
, flags
);
1442 while ((bio
= bio_list_pop(&bios
))) {
1443 struct dm_thin_endio_hook
*h
= dm_get_mapinfo(bio
)->ptr
;
1444 struct thin_c
*tc
= h
->tc
;
1447 * If we've got no free new_mapping structs, and processing
1448 * this bio might require one, we pause until there are some
1449 * prepared mappings to process.
1451 if (ensure_next_mapping(pool
)) {
1452 spin_lock_irqsave(&pool
->lock
, flags
);
1453 bio_list_merge(&pool
->deferred_bios
, &bios
);
1454 spin_unlock_irqrestore(&pool
->lock
, flags
);
1459 if (bio
->bi_rw
& REQ_DISCARD
)
1460 process_discard(tc
, bio
);
1462 process_bio(tc
, bio
);
1466 * If there are any deferred flush bios, we must commit
1467 * the metadata before issuing them.
1469 bio_list_init(&bios
);
1470 spin_lock_irqsave(&pool
->lock
, flags
);
1471 bio_list_merge(&bios
, &pool
->deferred_flush_bios
);
1472 bio_list_init(&pool
->deferred_flush_bios
);
1473 spin_unlock_irqrestore(&pool
->lock
, flags
);
1475 if (bio_list_empty(&bios
) && !need_commit_due_to_time(pool
))
1478 r
= dm_pool_commit_metadata(pool
->pmd
);
1480 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
1482 while ((bio
= bio_list_pop(&bios
)))
1486 pool
->last_commit_jiffies
= jiffies
;
1488 while ((bio
= bio_list_pop(&bios
)))
1489 generic_make_request(bio
);
1492 static void do_worker(struct work_struct
*ws
)
1494 struct pool
*pool
= container_of(ws
, struct pool
, worker
);
1496 process_prepared(pool
, &pool
->prepared_mappings
, process_prepared_mapping
);
1497 process_prepared(pool
, &pool
->prepared_discards
, process_prepared_discard
);
1498 process_deferred_bios(pool
);
1502 * We want to commit periodically so that not too much
1503 * unwritten data builds up.
1505 static void do_waker(struct work_struct
*ws
)
1507 struct pool
*pool
= container_of(to_delayed_work(ws
), struct pool
, waker
);
1509 queue_delayed_work(pool
->wq
, &pool
->waker
, COMMIT_PERIOD
);
1512 /*----------------------------------------------------------------*/
1515 * Mapping functions.
1519 * Called only while mapping a thin bio to hand it over to the workqueue.
1521 static void thin_defer_bio(struct thin_c
*tc
, struct bio
*bio
)
1523 unsigned long flags
;
1524 struct pool
*pool
= tc
->pool
;
1526 spin_lock_irqsave(&pool
->lock
, flags
);
1527 bio_list_add(&pool
->deferred_bios
, bio
);
1528 spin_unlock_irqrestore(&pool
->lock
, flags
);
1533 static struct dm_thin_endio_hook
*thin_hook_bio(struct thin_c
*tc
, struct bio
*bio
)
1535 struct pool
*pool
= tc
->pool
;
1536 struct dm_thin_endio_hook
*h
= mempool_alloc(pool
->endio_hook_pool
, GFP_NOIO
);
1539 h
->shared_read_entry
= NULL
;
1540 h
->all_io_entry
= bio
->bi_rw
& REQ_DISCARD
? NULL
: ds_inc(&pool
->all_io_ds
);
1541 h
->overwrite_mapping
= NULL
;
1547 * Non-blocking function called from the thin target's map function.
1549 static int thin_bio_map(struct dm_target
*ti
, struct bio
*bio
,
1550 union map_info
*map_context
)
1553 struct thin_c
*tc
= ti
->private;
1554 dm_block_t block
= get_bio_block(tc
, bio
);
1555 struct dm_thin_device
*td
= tc
->td
;
1556 struct dm_thin_lookup_result result
;
1558 map_context
->ptr
= thin_hook_bio(tc
, bio
);
1559 if (bio
->bi_rw
& (REQ_DISCARD
| REQ_FLUSH
| REQ_FUA
)) {
1560 thin_defer_bio(tc
, bio
);
1561 return DM_MAPIO_SUBMITTED
;
1564 r
= dm_thin_find_block(td
, block
, 0, &result
);
1567 * Note that we defer readahead too.
1571 if (unlikely(result
.shared
)) {
1573 * We have a race condition here between the
1574 * result.shared value returned by the lookup and
1575 * snapshot creation, which may cause new
1578 * To avoid this always quiesce the origin before
1579 * taking the snap. You want to do this anyway to
1580 * ensure a consistent application view
1583 * More distant ancestors are irrelevant. The
1584 * shared flag will be set in their case.
1586 thin_defer_bio(tc
, bio
);
1587 r
= DM_MAPIO_SUBMITTED
;
1589 remap(tc
, bio
, result
.block
);
1590 r
= DM_MAPIO_REMAPPED
;
1596 * In future, the failed dm_thin_find_block above could
1597 * provide the hint to load the metadata into cache.
1600 thin_defer_bio(tc
, bio
);
1601 r
= DM_MAPIO_SUBMITTED
;
1608 static int pool_is_congested(struct dm_target_callbacks
*cb
, int bdi_bits
)
1611 unsigned long flags
;
1612 struct pool_c
*pt
= container_of(cb
, struct pool_c
, callbacks
);
1614 spin_lock_irqsave(&pt
->pool
->lock
, flags
);
1615 r
= !bio_list_empty(&pt
->pool
->retry_on_resume_list
);
1616 spin_unlock_irqrestore(&pt
->pool
->lock
, flags
);
1619 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1620 r
= bdi_congested(&q
->backing_dev_info
, bdi_bits
);
1626 static void __requeue_bios(struct pool
*pool
)
1628 bio_list_merge(&pool
->deferred_bios
, &pool
->retry_on_resume_list
);
1629 bio_list_init(&pool
->retry_on_resume_list
);
1632 /*----------------------------------------------------------------
1633 * Binding of control targets to a pool object
1634 *--------------------------------------------------------------*/
1635 static int bind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1637 struct pool_c
*pt
= ti
->private;
1640 pool
->low_water_blocks
= pt
->low_water_blocks
;
1644 * If discard_passdown was enabled verify that the data device
1645 * supports discards. Disable discard_passdown if not; otherwise
1646 * -EOPNOTSUPP will be returned.
1648 if (pt
->pf
.discard_passdown
) {
1649 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1650 if (!q
|| !blk_queue_discard(q
)) {
1651 char buf
[BDEVNAME_SIZE
];
1652 DMWARN("Discard unsupported by data device (%s): Disabling discard passdown.",
1653 bdevname(pt
->data_dev
->bdev
, buf
));
1654 pool
->pf
.discard_passdown
= 0;
1661 static void unbind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1667 /*----------------------------------------------------------------
1669 *--------------------------------------------------------------*/
1670 /* Initialize pool features. */
1671 static void pool_features_init(struct pool_features
*pf
)
1673 pf
->zero_new_blocks
= 1;
1674 pf
->discard_enabled
= 1;
1675 pf
->discard_passdown
= 1;
1678 static void __pool_destroy(struct pool
*pool
)
1680 __pool_table_remove(pool
);
1682 if (dm_pool_metadata_close(pool
->pmd
) < 0)
1683 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1685 prison_destroy(pool
->prison
);
1686 dm_kcopyd_client_destroy(pool
->copier
);
1689 destroy_workqueue(pool
->wq
);
1691 if (pool
->next_mapping
)
1692 mempool_free(pool
->next_mapping
, pool
->mapping_pool
);
1693 mempool_destroy(pool
->mapping_pool
);
1694 mempool_destroy(pool
->endio_hook_pool
);
1698 static struct kmem_cache
*_new_mapping_cache
;
1699 static struct kmem_cache
*_endio_hook_cache
;
1701 static struct pool
*pool_create(struct mapped_device
*pool_md
,
1702 struct block_device
*metadata_dev
,
1703 unsigned long block_size
, char **error
)
1708 struct dm_pool_metadata
*pmd
;
1710 pmd
= dm_pool_metadata_open(metadata_dev
, block_size
);
1712 *error
= "Error creating metadata object";
1713 return (struct pool
*)pmd
;
1716 pool
= kmalloc(sizeof(*pool
), GFP_KERNEL
);
1718 *error
= "Error allocating memory for pool";
1719 err_p
= ERR_PTR(-ENOMEM
);
1724 pool
->sectors_per_block
= block_size
;
1725 pool
->block_shift
= ffs(block_size
) - 1;
1726 pool
->offset_mask
= block_size
- 1;
1727 pool
->low_water_blocks
= 0;
1728 pool_features_init(&pool
->pf
);
1729 pool
->prison
= prison_create(PRISON_CELLS
);
1730 if (!pool
->prison
) {
1731 *error
= "Error creating pool's bio prison";
1732 err_p
= ERR_PTR(-ENOMEM
);
1736 pool
->copier
= dm_kcopyd_client_create();
1737 if (IS_ERR(pool
->copier
)) {
1738 r
= PTR_ERR(pool
->copier
);
1739 *error
= "Error creating pool's kcopyd client";
1741 goto bad_kcopyd_client
;
1745 * Create singlethreaded workqueue that will service all devices
1746 * that use this metadata.
1748 pool
->wq
= alloc_ordered_workqueue("dm-" DM_MSG_PREFIX
, WQ_MEM_RECLAIM
);
1750 *error
= "Error creating pool's workqueue";
1751 err_p
= ERR_PTR(-ENOMEM
);
1755 INIT_WORK(&pool
->worker
, do_worker
);
1756 INIT_DELAYED_WORK(&pool
->waker
, do_waker
);
1757 spin_lock_init(&pool
->lock
);
1758 bio_list_init(&pool
->deferred_bios
);
1759 bio_list_init(&pool
->deferred_flush_bios
);
1760 INIT_LIST_HEAD(&pool
->prepared_mappings
);
1761 INIT_LIST_HEAD(&pool
->prepared_discards
);
1762 pool
->low_water_triggered
= 0;
1763 pool
->no_free_space
= 0;
1764 bio_list_init(&pool
->retry_on_resume_list
);
1765 ds_init(&pool
->shared_read_ds
);
1766 ds_init(&pool
->all_io_ds
);
1768 pool
->next_mapping
= NULL
;
1769 pool
->mapping_pool
= mempool_create_slab_pool(MAPPING_POOL_SIZE
,
1770 _new_mapping_cache
);
1771 if (!pool
->mapping_pool
) {
1772 *error
= "Error creating pool's mapping mempool";
1773 err_p
= ERR_PTR(-ENOMEM
);
1774 goto bad_mapping_pool
;
1777 pool
->endio_hook_pool
= mempool_create_slab_pool(ENDIO_HOOK_POOL_SIZE
,
1779 if (!pool
->endio_hook_pool
) {
1780 *error
= "Error creating pool's endio_hook mempool";
1781 err_p
= ERR_PTR(-ENOMEM
);
1782 goto bad_endio_hook_pool
;
1784 pool
->ref_count
= 1;
1785 pool
->last_commit_jiffies
= jiffies
;
1786 pool
->pool_md
= pool_md
;
1787 pool
->md_dev
= metadata_dev
;
1788 __pool_table_insert(pool
);
1792 bad_endio_hook_pool
:
1793 mempool_destroy(pool
->mapping_pool
);
1795 destroy_workqueue(pool
->wq
);
1797 dm_kcopyd_client_destroy(pool
->copier
);
1799 prison_destroy(pool
->prison
);
1803 if (dm_pool_metadata_close(pmd
))
1804 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1809 static void __pool_inc(struct pool
*pool
)
1811 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1815 static void __pool_dec(struct pool
*pool
)
1817 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1818 BUG_ON(!pool
->ref_count
);
1819 if (!--pool
->ref_count
)
1820 __pool_destroy(pool
);
1823 static struct pool
*__pool_find(struct mapped_device
*pool_md
,
1824 struct block_device
*metadata_dev
,
1825 unsigned long block_size
, char **error
,
1828 struct pool
*pool
= __pool_table_lookup_metadata_dev(metadata_dev
);
1831 if (pool
->pool_md
!= pool_md
)
1832 return ERR_PTR(-EBUSY
);
1836 pool
= __pool_table_lookup(pool_md
);
1838 if (pool
->md_dev
!= metadata_dev
)
1839 return ERR_PTR(-EINVAL
);
1843 pool
= pool_create(pool_md
, metadata_dev
, block_size
, error
);
1851 /*----------------------------------------------------------------
1852 * Pool target methods
1853 *--------------------------------------------------------------*/
1854 static void pool_dtr(struct dm_target
*ti
)
1856 struct pool_c
*pt
= ti
->private;
1858 mutex_lock(&dm_thin_pool_table
.mutex
);
1860 unbind_control_target(pt
->pool
, ti
);
1861 __pool_dec(pt
->pool
);
1862 dm_put_device(ti
, pt
->metadata_dev
);
1863 dm_put_device(ti
, pt
->data_dev
);
1866 mutex_unlock(&dm_thin_pool_table
.mutex
);
1869 static int parse_pool_features(struct dm_arg_set
*as
, struct pool_features
*pf
,
1870 struct dm_target
*ti
)
1874 const char *arg_name
;
1876 static struct dm_arg _args
[] = {
1877 {0, 3, "Invalid number of pool feature arguments"},
1881 * No feature arguments supplied.
1886 r
= dm_read_arg_group(_args
, as
, &argc
, &ti
->error
);
1890 while (argc
&& !r
) {
1891 arg_name
= dm_shift_arg(as
);
1894 if (!strcasecmp(arg_name
, "skip_block_zeroing")) {
1895 pf
->zero_new_blocks
= 0;
1897 } else if (!strcasecmp(arg_name
, "ignore_discard")) {
1898 pf
->discard_enabled
= 0;
1900 } else if (!strcasecmp(arg_name
, "no_discard_passdown")) {
1901 pf
->discard_passdown
= 0;
1905 ti
->error
= "Unrecognised pool feature requested";
1913 * thin-pool <metadata dev> <data dev>
1914 * <data block size (sectors)>
1915 * <low water mark (blocks)>
1916 * [<#feature args> [<arg>]*]
1918 * Optional feature arguments are:
1919 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1920 * ignore_discard: disable discard
1921 * no_discard_passdown: don't pass discards down to the data device
1923 static int pool_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
1925 int r
, pool_created
= 0;
1928 struct pool_features pf
;
1929 struct dm_arg_set as
;
1930 struct dm_dev
*data_dev
;
1931 unsigned long block_size
;
1932 dm_block_t low_water_blocks
;
1933 struct dm_dev
*metadata_dev
;
1934 sector_t metadata_dev_size
;
1935 char b
[BDEVNAME_SIZE
];
1938 * FIXME Remove validation from scope of lock.
1940 mutex_lock(&dm_thin_pool_table
.mutex
);
1943 ti
->error
= "Invalid argument count";
1950 r
= dm_get_device(ti
, argv
[0], FMODE_READ
| FMODE_WRITE
, &metadata_dev
);
1952 ti
->error
= "Error opening metadata block device";
1956 metadata_dev_size
= i_size_read(metadata_dev
->bdev
->bd_inode
) >> SECTOR_SHIFT
;
1957 if (metadata_dev_size
> THIN_METADATA_MAX_SECTORS_WARNING
)
1958 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1959 bdevname(metadata_dev
->bdev
, b
), THIN_METADATA_MAX_SECTORS
);
1961 r
= dm_get_device(ti
, argv
[1], FMODE_READ
| FMODE_WRITE
, &data_dev
);
1963 ti
->error
= "Error getting data device";
1967 if (kstrtoul(argv
[2], 10, &block_size
) || !block_size
||
1968 block_size
< DATA_DEV_BLOCK_SIZE_MIN_SECTORS
||
1969 block_size
> DATA_DEV_BLOCK_SIZE_MAX_SECTORS
||
1970 !is_power_of_2(block_size
)) {
1971 ti
->error
= "Invalid block size";
1976 if (kstrtoull(argv
[3], 10, (unsigned long long *)&low_water_blocks
)) {
1977 ti
->error
= "Invalid low water mark";
1983 * Set default pool features.
1985 pool_features_init(&pf
);
1987 dm_consume_args(&as
, 4);
1988 r
= parse_pool_features(&as
, &pf
, ti
);
1992 pt
= kzalloc(sizeof(*pt
), GFP_KERNEL
);
1998 pool
= __pool_find(dm_table_get_md(ti
->table
), metadata_dev
->bdev
,
1999 block_size
, &ti
->error
, &pool_created
);
2006 * 'pool_created' reflects whether this is the first table load.
2007 * Top level discard support is not allowed to be changed after
2008 * initial load. This would require a pool reload to trigger thin
2011 if (!pool_created
&& pf
.discard_enabled
!= pool
->pf
.discard_enabled
) {
2012 ti
->error
= "Discard support cannot be disabled once enabled";
2014 goto out_flags_changed
;
2019 pt
->metadata_dev
= metadata_dev
;
2020 pt
->data_dev
= data_dev
;
2021 pt
->low_water_blocks
= low_water_blocks
;
2023 ti
->num_flush_requests
= 1;
2025 * Only need to enable discards if the pool should pass
2026 * them down to the data device. The thin device's discard
2027 * processing will cause mappings to be removed from the btree.
2029 if (pf
.discard_enabled
&& pf
.discard_passdown
) {
2030 ti
->num_discard_requests
= 1;
2032 * Setting 'discards_supported' circumvents the normal
2033 * stacking of discard limits (this keeps the pool and
2034 * thin devices' discard limits consistent).
2036 ti
->discards_supported
= 1;
2040 pt
->callbacks
.congested_fn
= pool_is_congested
;
2041 dm_table_add_target_callbacks(ti
->table
, &pt
->callbacks
);
2043 mutex_unlock(&dm_thin_pool_table
.mutex
);
2052 dm_put_device(ti
, data_dev
);
2054 dm_put_device(ti
, metadata_dev
);
2056 mutex_unlock(&dm_thin_pool_table
.mutex
);
2061 static int pool_map(struct dm_target
*ti
, struct bio
*bio
,
2062 union map_info
*map_context
)
2065 struct pool_c
*pt
= ti
->private;
2066 struct pool
*pool
= pt
->pool
;
2067 unsigned long flags
;
2070 * As this is a singleton target, ti->begin is always zero.
2072 spin_lock_irqsave(&pool
->lock
, flags
);
2073 bio
->bi_bdev
= pt
->data_dev
->bdev
;
2074 r
= DM_MAPIO_REMAPPED
;
2075 spin_unlock_irqrestore(&pool
->lock
, flags
);
2081 * Retrieves the number of blocks of the data device from
2082 * the superblock and compares it to the actual device size,
2083 * thus resizing the data device in case it has grown.
2085 * This both copes with opening preallocated data devices in the ctr
2086 * being followed by a resume
2088 * calling the resume method individually after userspace has
2089 * grown the data device in reaction to a table event.
2091 static int pool_preresume(struct dm_target
*ti
)
2094 struct pool_c
*pt
= ti
->private;
2095 struct pool
*pool
= pt
->pool
;
2096 dm_block_t data_size
, sb_data_size
;
2099 * Take control of the pool object.
2101 r
= bind_control_target(pool
, ti
);
2105 data_size
= ti
->len
>> pool
->block_shift
;
2106 r
= dm_pool_get_data_dev_size(pool
->pmd
, &sb_data_size
);
2108 DMERR("failed to retrieve data device size");
2112 if (data_size
< sb_data_size
) {
2113 DMERR("pool target too small, is %llu blocks (expected %llu)",
2114 data_size
, sb_data_size
);
2117 } else if (data_size
> sb_data_size
) {
2118 r
= dm_pool_resize_data_dev(pool
->pmd
, data_size
);
2120 DMERR("failed to resize data device");
2124 r
= dm_pool_commit_metadata(pool
->pmd
);
2126 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2135 static void pool_resume(struct dm_target
*ti
)
2137 struct pool_c
*pt
= ti
->private;
2138 struct pool
*pool
= pt
->pool
;
2139 unsigned long flags
;
2141 spin_lock_irqsave(&pool
->lock
, flags
);
2142 pool
->low_water_triggered
= 0;
2143 pool
->no_free_space
= 0;
2144 __requeue_bios(pool
);
2145 spin_unlock_irqrestore(&pool
->lock
, flags
);
2147 do_waker(&pool
->waker
.work
);
2150 static void pool_postsuspend(struct dm_target
*ti
)
2153 struct pool_c
*pt
= ti
->private;
2154 struct pool
*pool
= pt
->pool
;
2156 cancel_delayed_work(&pool
->waker
);
2157 flush_workqueue(pool
->wq
);
2159 r
= dm_pool_commit_metadata(pool
->pmd
);
2161 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2163 /* FIXME: invalidate device? error the next FUA or FLUSH bio ?*/
2167 static int check_arg_count(unsigned argc
, unsigned args_required
)
2169 if (argc
!= args_required
) {
2170 DMWARN("Message received with %u arguments instead of %u.",
2171 argc
, args_required
);
2178 static int read_dev_id(char *arg
, dm_thin_id
*dev_id
, int warning
)
2180 if (!kstrtoull(arg
, 10, (unsigned long long *)dev_id
) &&
2181 *dev_id
<= MAX_DEV_ID
)
2185 DMWARN("Message received with invalid device id: %s", arg
);
2190 static int process_create_thin_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2195 r
= check_arg_count(argc
, 2);
2199 r
= read_dev_id(argv
[1], &dev_id
, 1);
2203 r
= dm_pool_create_thin(pool
->pmd
, dev_id
);
2205 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2213 static int process_create_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2216 dm_thin_id origin_dev_id
;
2219 r
= check_arg_count(argc
, 3);
2223 r
= read_dev_id(argv
[1], &dev_id
, 1);
2227 r
= read_dev_id(argv
[2], &origin_dev_id
, 1);
2231 r
= dm_pool_create_snap(pool
->pmd
, dev_id
, origin_dev_id
);
2233 DMWARN("Creation of new snapshot %s of device %s failed.",
2241 static int process_delete_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2246 r
= check_arg_count(argc
, 2);
2250 r
= read_dev_id(argv
[1], &dev_id
, 1);
2254 r
= dm_pool_delete_thin_device(pool
->pmd
, dev_id
);
2256 DMWARN("Deletion of thin device %s failed.", argv
[1]);
2261 static int process_set_transaction_id_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2263 dm_thin_id old_id
, new_id
;
2266 r
= check_arg_count(argc
, 3);
2270 if (kstrtoull(argv
[1], 10, (unsigned long long *)&old_id
)) {
2271 DMWARN("set_transaction_id message: Unrecognised id %s.", argv
[1]);
2275 if (kstrtoull(argv
[2], 10, (unsigned long long *)&new_id
)) {
2276 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv
[2]);
2280 r
= dm_pool_set_metadata_transaction_id(pool
->pmd
, old_id
, new_id
);
2282 DMWARN("Failed to change transaction id from %s to %s.",
2290 static int process_reserve_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2294 r
= check_arg_count(argc
, 1);
2298 r
= dm_pool_commit_metadata(pool
->pmd
);
2300 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
2305 r
= dm_pool_reserve_metadata_snap(pool
->pmd
);
2307 DMWARN("reserve_metadata_snap message failed.");
2312 static int process_release_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2316 r
= check_arg_count(argc
, 1);
2320 r
= dm_pool_release_metadata_snap(pool
->pmd
);
2322 DMWARN("release_metadata_snap message failed.");
2328 * Messages supported:
2329 * create_thin <dev_id>
2330 * create_snap <dev_id> <origin_id>
2332 * trim <dev_id> <new_size_in_sectors>
2333 * set_transaction_id <current_trans_id> <new_trans_id>
2334 * reserve_metadata_snap
2335 * release_metadata_snap
2337 static int pool_message(struct dm_target
*ti
, unsigned argc
, char **argv
)
2340 struct pool_c
*pt
= ti
->private;
2341 struct pool
*pool
= pt
->pool
;
2343 if (!strcasecmp(argv
[0], "create_thin"))
2344 r
= process_create_thin_mesg(argc
, argv
, pool
);
2346 else if (!strcasecmp(argv
[0], "create_snap"))
2347 r
= process_create_snap_mesg(argc
, argv
, pool
);
2349 else if (!strcasecmp(argv
[0], "delete"))
2350 r
= process_delete_mesg(argc
, argv
, pool
);
2352 else if (!strcasecmp(argv
[0], "set_transaction_id"))
2353 r
= process_set_transaction_id_mesg(argc
, argv
, pool
);
2355 else if (!strcasecmp(argv
[0], "reserve_metadata_snap"))
2356 r
= process_reserve_metadata_snap_mesg(argc
, argv
, pool
);
2358 else if (!strcasecmp(argv
[0], "release_metadata_snap"))
2359 r
= process_release_metadata_snap_mesg(argc
, argv
, pool
);
2362 DMWARN("Unrecognised thin pool target message received: %s", argv
[0]);
2365 r
= dm_pool_commit_metadata(pool
->pmd
);
2367 DMERR("%s message: dm_pool_commit_metadata() failed, error = %d",
2376 * <transaction id> <used metadata sectors>/<total metadata sectors>
2377 * <used data sectors>/<total data sectors> <held metadata root>
2379 static int pool_status(struct dm_target
*ti
, status_type_t type
,
2380 char *result
, unsigned maxlen
)
2384 uint64_t transaction_id
;
2385 dm_block_t nr_free_blocks_data
;
2386 dm_block_t nr_free_blocks_metadata
;
2387 dm_block_t nr_blocks_data
;
2388 dm_block_t nr_blocks_metadata
;
2389 dm_block_t held_root
;
2390 char buf
[BDEVNAME_SIZE
];
2391 char buf2
[BDEVNAME_SIZE
];
2392 struct pool_c
*pt
= ti
->private;
2393 struct pool
*pool
= pt
->pool
;
2396 case STATUSTYPE_INFO
:
2397 r
= dm_pool_get_metadata_transaction_id(pool
->pmd
,
2402 r
= dm_pool_get_free_metadata_block_count(pool
->pmd
,
2403 &nr_free_blocks_metadata
);
2407 r
= dm_pool_get_metadata_dev_size(pool
->pmd
, &nr_blocks_metadata
);
2411 r
= dm_pool_get_free_block_count(pool
->pmd
,
2412 &nr_free_blocks_data
);
2416 r
= dm_pool_get_data_dev_size(pool
->pmd
, &nr_blocks_data
);
2420 r
= dm_pool_get_metadata_snap(pool
->pmd
, &held_root
);
2424 DMEMIT("%llu %llu/%llu %llu/%llu ",
2425 (unsigned long long)transaction_id
,
2426 (unsigned long long)(nr_blocks_metadata
- nr_free_blocks_metadata
),
2427 (unsigned long long)nr_blocks_metadata
,
2428 (unsigned long long)(nr_blocks_data
- nr_free_blocks_data
),
2429 (unsigned long long)nr_blocks_data
);
2432 DMEMIT("%llu", held_root
);
2438 case STATUSTYPE_TABLE
:
2439 DMEMIT("%s %s %lu %llu ",
2440 format_dev_t(buf
, pt
->metadata_dev
->bdev
->bd_dev
),
2441 format_dev_t(buf2
, pt
->data_dev
->bdev
->bd_dev
),
2442 (unsigned long)pool
->sectors_per_block
,
2443 (unsigned long long)pt
->low_water_blocks
);
2445 count
= !pool
->pf
.zero_new_blocks
+ !pool
->pf
.discard_enabled
+
2446 !pt
->pf
.discard_passdown
;
2447 DMEMIT("%u ", count
);
2449 if (!pool
->pf
.zero_new_blocks
)
2450 DMEMIT("skip_block_zeroing ");
2452 if (!pool
->pf
.discard_enabled
)
2453 DMEMIT("ignore_discard ");
2455 if (!pt
->pf
.discard_passdown
)
2456 DMEMIT("no_discard_passdown ");
2464 static int pool_iterate_devices(struct dm_target
*ti
,
2465 iterate_devices_callout_fn fn
, void *data
)
2467 struct pool_c
*pt
= ti
->private;
2469 return fn(ti
, pt
->data_dev
, 0, ti
->len
, data
);
2472 static int pool_merge(struct dm_target
*ti
, struct bvec_merge_data
*bvm
,
2473 struct bio_vec
*biovec
, int max_size
)
2475 struct pool_c
*pt
= ti
->private;
2476 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
2478 if (!q
->merge_bvec_fn
)
2481 bvm
->bi_bdev
= pt
->data_dev
->bdev
;
2483 return min(max_size
, q
->merge_bvec_fn(q
, bvm
, biovec
));
2486 static void set_discard_limits(struct pool
*pool
, struct queue_limits
*limits
)
2489 * FIXME: these limits may be incompatible with the pool's data device
2491 limits
->max_discard_sectors
= pool
->sectors_per_block
;
2494 * This is just a hint, and not enforced. We have to cope with
2495 * bios that overlap 2 blocks.
2497 limits
->discard_granularity
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
2498 limits
->discard_zeroes_data
= pool
->pf
.zero_new_blocks
;
2501 static void pool_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
2503 struct pool_c
*pt
= ti
->private;
2504 struct pool
*pool
= pt
->pool
;
2506 blk_limits_io_min(limits
, 0);
2507 blk_limits_io_opt(limits
, pool
->sectors_per_block
<< SECTOR_SHIFT
);
2508 if (pool
->pf
.discard_enabled
)
2509 set_discard_limits(pool
, limits
);
2512 static struct target_type pool_target
= {
2513 .name
= "thin-pool",
2514 .features
= DM_TARGET_SINGLETON
| DM_TARGET_ALWAYS_WRITEABLE
|
2515 DM_TARGET_IMMUTABLE
,
2516 .version
= {1, 2, 0},
2517 .module
= THIS_MODULE
,
2521 .postsuspend
= pool_postsuspend
,
2522 .preresume
= pool_preresume
,
2523 .resume
= pool_resume
,
2524 .message
= pool_message
,
2525 .status
= pool_status
,
2526 .merge
= pool_merge
,
2527 .iterate_devices
= pool_iterate_devices
,
2528 .io_hints
= pool_io_hints
,
2531 /*----------------------------------------------------------------
2532 * Thin target methods
2533 *--------------------------------------------------------------*/
2534 static void thin_dtr(struct dm_target
*ti
)
2536 struct thin_c
*tc
= ti
->private;
2538 mutex_lock(&dm_thin_pool_table
.mutex
);
2540 __pool_dec(tc
->pool
);
2541 dm_pool_close_thin_device(tc
->td
);
2542 dm_put_device(ti
, tc
->pool_dev
);
2544 dm_put_device(ti
, tc
->origin_dev
);
2547 mutex_unlock(&dm_thin_pool_table
.mutex
);
2551 * Thin target parameters:
2553 * <pool_dev> <dev_id> [origin_dev]
2555 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2556 * dev_id: the internal device identifier
2557 * origin_dev: a device external to the pool that should act as the origin
2559 * If the pool device has discards disabled, they get disabled for the thin
2562 static int thin_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
2566 struct dm_dev
*pool_dev
, *origin_dev
;
2567 struct mapped_device
*pool_md
;
2569 mutex_lock(&dm_thin_pool_table
.mutex
);
2571 if (argc
!= 2 && argc
!= 3) {
2572 ti
->error
= "Invalid argument count";
2577 tc
= ti
->private = kzalloc(sizeof(*tc
), GFP_KERNEL
);
2579 ti
->error
= "Out of memory";
2585 r
= dm_get_device(ti
, argv
[2], FMODE_READ
, &origin_dev
);
2587 ti
->error
= "Error opening origin device";
2588 goto bad_origin_dev
;
2590 tc
->origin_dev
= origin_dev
;
2593 r
= dm_get_device(ti
, argv
[0], dm_table_get_mode(ti
->table
), &pool_dev
);
2595 ti
->error
= "Error opening pool device";
2598 tc
->pool_dev
= pool_dev
;
2600 if (read_dev_id(argv
[1], (unsigned long long *)&tc
->dev_id
, 0)) {
2601 ti
->error
= "Invalid device id";
2606 pool_md
= dm_get_md(tc
->pool_dev
->bdev
->bd_dev
);
2608 ti
->error
= "Couldn't get pool mapped device";
2613 tc
->pool
= __pool_table_lookup(pool_md
);
2615 ti
->error
= "Couldn't find pool object";
2617 goto bad_pool_lookup
;
2619 __pool_inc(tc
->pool
);
2621 r
= dm_pool_open_thin_device(tc
->pool
->pmd
, tc
->dev_id
, &tc
->td
);
2623 ti
->error
= "Couldn't open thin internal device";
2627 ti
->split_io
= tc
->pool
->sectors_per_block
;
2628 ti
->num_flush_requests
= 1;
2630 /* In case the pool supports discards, pass them on. */
2631 if (tc
->pool
->pf
.discard_enabled
) {
2632 ti
->discards_supported
= 1;
2633 ti
->num_discard_requests
= 1;
2634 ti
->discard_zeroes_data_unsupported
= 1;
2639 mutex_unlock(&dm_thin_pool_table
.mutex
);
2644 __pool_dec(tc
->pool
);
2648 dm_put_device(ti
, tc
->pool_dev
);
2651 dm_put_device(ti
, tc
->origin_dev
);
2655 mutex_unlock(&dm_thin_pool_table
.mutex
);
2660 static int thin_map(struct dm_target
*ti
, struct bio
*bio
,
2661 union map_info
*map_context
)
2663 bio
->bi_sector
= dm_target_offset(ti
, bio
->bi_sector
);
2665 return thin_bio_map(ti
, bio
, map_context
);
2668 static int thin_endio(struct dm_target
*ti
,
2669 struct bio
*bio
, int err
,
2670 union map_info
*map_context
)
2672 unsigned long flags
;
2673 struct dm_thin_endio_hook
*h
= map_context
->ptr
;
2674 struct list_head work
;
2675 struct dm_thin_new_mapping
*m
, *tmp
;
2676 struct pool
*pool
= h
->tc
->pool
;
2678 if (h
->shared_read_entry
) {
2679 INIT_LIST_HEAD(&work
);
2680 ds_dec(h
->shared_read_entry
, &work
);
2682 spin_lock_irqsave(&pool
->lock
, flags
);
2683 list_for_each_entry_safe(m
, tmp
, &work
, list
) {
2686 __maybe_add_mapping(m
);
2688 spin_unlock_irqrestore(&pool
->lock
, flags
);
2691 if (h
->all_io_entry
) {
2692 INIT_LIST_HEAD(&work
);
2693 ds_dec(h
->all_io_entry
, &work
);
2694 spin_lock_irqsave(&pool
->lock
, flags
);
2695 list_for_each_entry_safe(m
, tmp
, &work
, list
)
2696 list_add(&m
->list
, &pool
->prepared_discards
);
2697 spin_unlock_irqrestore(&pool
->lock
, flags
);
2700 mempool_free(h
, pool
->endio_hook_pool
);
2705 static void thin_postsuspend(struct dm_target
*ti
)
2707 if (dm_noflush_suspending(ti
))
2708 requeue_io((struct thin_c
*)ti
->private);
2712 * <nr mapped sectors> <highest mapped sector>
2714 static int thin_status(struct dm_target
*ti
, status_type_t type
,
2715 char *result
, unsigned maxlen
)
2719 dm_block_t mapped
, highest
;
2720 char buf
[BDEVNAME_SIZE
];
2721 struct thin_c
*tc
= ti
->private;
2727 case STATUSTYPE_INFO
:
2728 r
= dm_thin_get_mapped_count(tc
->td
, &mapped
);
2732 r
= dm_thin_get_highest_mapped_block(tc
->td
, &highest
);
2736 DMEMIT("%llu ", mapped
* tc
->pool
->sectors_per_block
);
2738 DMEMIT("%llu", ((highest
+ 1) *
2739 tc
->pool
->sectors_per_block
) - 1);
2744 case STATUSTYPE_TABLE
:
2746 format_dev_t(buf
, tc
->pool_dev
->bdev
->bd_dev
),
2747 (unsigned long) tc
->dev_id
);
2749 DMEMIT(" %s", format_dev_t(buf
, tc
->origin_dev
->bdev
->bd_dev
));
2757 static int thin_iterate_devices(struct dm_target
*ti
,
2758 iterate_devices_callout_fn fn
, void *data
)
2761 struct thin_c
*tc
= ti
->private;
2764 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2765 * we follow a more convoluted path through to the pool's target.
2768 return 0; /* nothing is bound */
2770 blocks
= tc
->pool
->ti
->len
>> tc
->pool
->block_shift
;
2772 return fn(ti
, tc
->pool_dev
, 0, tc
->pool
->sectors_per_block
* blocks
, data
);
2777 static void thin_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
2779 struct thin_c
*tc
= ti
->private;
2780 struct pool
*pool
= tc
->pool
;
2782 blk_limits_io_min(limits
, 0);
2783 blk_limits_io_opt(limits
, pool
->sectors_per_block
<< SECTOR_SHIFT
);
2784 set_discard_limits(pool
, limits
);
2787 static struct target_type thin_target
= {
2789 .version
= {1, 1, 0},
2790 .module
= THIS_MODULE
,
2794 .end_io
= thin_endio
,
2795 .postsuspend
= thin_postsuspend
,
2796 .status
= thin_status
,
2797 .iterate_devices
= thin_iterate_devices
,
2798 .io_hints
= thin_io_hints
,
2801 /*----------------------------------------------------------------*/
2803 static int __init
dm_thin_init(void)
2809 r
= dm_register_target(&thin_target
);
2813 r
= dm_register_target(&pool_target
);
2815 goto bad_pool_target
;
2819 _cell_cache
= KMEM_CACHE(dm_bio_prison_cell
, 0);
2821 goto bad_cell_cache
;
2823 _new_mapping_cache
= KMEM_CACHE(dm_thin_new_mapping
, 0);
2824 if (!_new_mapping_cache
)
2825 goto bad_new_mapping_cache
;
2827 _endio_hook_cache
= KMEM_CACHE(dm_thin_endio_hook
, 0);
2828 if (!_endio_hook_cache
)
2829 goto bad_endio_hook_cache
;
2833 bad_endio_hook_cache
:
2834 kmem_cache_destroy(_new_mapping_cache
);
2835 bad_new_mapping_cache
:
2836 kmem_cache_destroy(_cell_cache
);
2838 dm_unregister_target(&pool_target
);
2840 dm_unregister_target(&thin_target
);
2845 static void dm_thin_exit(void)
2847 dm_unregister_target(&thin_target
);
2848 dm_unregister_target(&pool_target
);
2850 kmem_cache_destroy(_cell_cache
);
2851 kmem_cache_destroy(_new_mapping_cache
);
2852 kmem_cache_destroy(_endio_hook_cache
);
2855 module_init(dm_thin_init
);
2856 module_exit(dm_thin_exit
);
2858 MODULE_DESCRIPTION(DM_NAME
" thin provisioning target");
2859 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2860 MODULE_LICENSE("GPL");