2 * Copyright (C) 2011-2012 Red Hat UK.
4 * This file is released under the GPL.
7 #include "dm-thin-metadata.h"
8 #include "dm-bio-prison.h"
11 #include <linux/device-mapper.h>
12 #include <linux/dm-io.h>
13 #include <linux/dm-kcopyd.h>
14 #include <linux/list.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
19 #define DM_MSG_PREFIX "thin"
24 #define ENDIO_HOOK_POOL_SIZE 1024
25 #define MAPPING_POOL_SIZE 1024
26 #define PRISON_CELLS 1024
27 #define COMMIT_PERIOD HZ
29 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle
,
30 "A percentage of time allocated for copy on write");
33 * The block size of the device holding pool data must be
34 * between 64KB and 1GB.
36 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
37 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
40 * Device id is restricted to 24 bits.
42 #define MAX_DEV_ID ((1 << 24) - 1)
45 * How do we handle breaking sharing of data blocks?
46 * =================================================
48 * We use a standard copy-on-write btree to store the mappings for the
49 * devices (note I'm talking about copy-on-write of the metadata here, not
50 * the data). When you take an internal snapshot you clone the root node
51 * of the origin btree. After this there is no concept of an origin or a
52 * snapshot. They are just two device trees that happen to point to the
55 * When we get a write in we decide if it's to a shared data block using
56 * some timestamp magic. If it is, we have to break sharing.
58 * Let's say we write to a shared block in what was the origin. The
61 * i) plug io further to this physical block. (see bio_prison code).
63 * ii) quiesce any read io to that shared data block. Obviously
64 * including all devices that share this block. (see dm_deferred_set code)
66 * iii) copy the data block to a newly allocate block. This step can be
67 * missed out if the io covers the block. (schedule_copy).
69 * iv) insert the new mapping into the origin's btree
70 * (process_prepared_mapping). This act of inserting breaks some
71 * sharing of btree nodes between the two devices. Breaking sharing only
72 * effects the btree of that specific device. Btrees for the other
73 * devices that share the block never change. The btree for the origin
74 * device as it was after the last commit is untouched, ie. we're using
75 * persistent data structures in the functional programming sense.
77 * v) unplug io to this physical block, including the io that triggered
78 * the breaking of sharing.
80 * Steps (ii) and (iii) occur in parallel.
82 * The metadata _doesn't_ need to be committed before the io continues. We
83 * get away with this because the io is always written to a _new_ block.
84 * If there's a crash, then:
86 * - The origin mapping will point to the old origin block (the shared
87 * one). This will contain the data as it was before the io that triggered
88 * the breaking of sharing came in.
90 * - The snap mapping still points to the old block. As it would after
93 * The downside of this scheme is the timestamp magic isn't perfect, and
94 * will continue to think that data block in the snapshot device is shared
95 * even after the write to the origin has broken sharing. I suspect data
96 * blocks will typically be shared by many different devices, so we're
97 * breaking sharing n + 1 times, rather than n, where n is the number of
98 * devices that reference this data block. At the moment I think the
99 * benefits far, far outweigh the disadvantages.
102 /*----------------------------------------------------------------*/
107 static void build_data_key(struct dm_thin_device
*td
,
108 dm_block_t b
, struct dm_cell_key
*key
)
111 key
->dev
= dm_thin_dev_id(td
);
115 static void build_virtual_key(struct dm_thin_device
*td
, dm_block_t b
,
116 struct dm_cell_key
*key
)
119 key
->dev
= dm_thin_dev_id(td
);
123 /*----------------------------------------------------------------*/
126 * A pool device ties together a metadata device and a data device. It
127 * also provides the interface for creating and destroying internal
130 struct dm_thin_new_mapping
;
133 * The pool runs in 3 modes. Ordered in degraded order for comparisons.
136 PM_WRITE
, /* metadata may be changed */
137 PM_READ_ONLY
, /* metadata may not be changed */
138 PM_FAIL
, /* all I/O fails */
141 struct pool_features
{
144 bool zero_new_blocks
:1;
145 bool discard_enabled
:1;
146 bool discard_passdown
:1;
150 typedef void (*process_bio_fn
)(struct thin_c
*tc
, struct bio
*bio
);
151 typedef void (*process_mapping_fn
)(struct dm_thin_new_mapping
*m
);
154 struct list_head list
;
155 struct dm_target
*ti
; /* Only set if a pool target is bound */
157 struct mapped_device
*pool_md
;
158 struct block_device
*md_dev
;
159 struct dm_pool_metadata
*pmd
;
161 dm_block_t low_water_blocks
;
162 uint32_t sectors_per_block
;
163 int sectors_per_block_shift
;
165 struct pool_features pf
;
166 unsigned low_water_triggered
:1; /* A dm event has been sent */
167 unsigned no_free_space
:1; /* A -ENOSPC warning has been issued */
169 struct dm_bio_prison
*prison
;
170 struct dm_kcopyd_client
*copier
;
172 struct workqueue_struct
*wq
;
173 struct work_struct worker
;
174 struct delayed_work waker
;
176 unsigned long last_commit_jiffies
;
180 struct bio_list deferred_bios
;
181 struct bio_list deferred_flush_bios
;
182 struct list_head prepared_mappings
;
183 struct list_head prepared_discards
;
185 struct bio_list retry_on_resume_list
;
187 struct dm_deferred_set
*shared_read_ds
;
188 struct dm_deferred_set
*all_io_ds
;
190 struct dm_thin_new_mapping
*next_mapping
;
191 mempool_t
*mapping_pool
;
193 process_bio_fn process_bio
;
194 process_bio_fn process_discard
;
196 process_mapping_fn process_prepared_mapping
;
197 process_mapping_fn process_prepared_discard
;
200 static enum pool_mode
get_pool_mode(struct pool
*pool
);
201 static void set_pool_mode(struct pool
*pool
, enum pool_mode mode
);
204 * Target context for a pool.
207 struct dm_target
*ti
;
209 struct dm_dev
*data_dev
;
210 struct dm_dev
*metadata_dev
;
211 struct dm_target_callbacks callbacks
;
213 dm_block_t low_water_blocks
;
214 struct pool_features requested_pf
; /* Features requested during table load */
215 struct pool_features adjusted_pf
; /* Features used after adjusting for constituent devices */
219 * Target context for a thin.
222 struct dm_dev
*pool_dev
;
223 struct dm_dev
*origin_dev
;
227 struct dm_thin_device
*td
;
230 /*----------------------------------------------------------------*/
233 * wake_worker() is used when new work is queued and when pool_resume is
234 * ready to continue deferred IO processing.
236 static void wake_worker(struct pool
*pool
)
238 queue_work(pool
->wq
, &pool
->worker
);
241 /*----------------------------------------------------------------*/
243 static int bio_detain(struct pool
*pool
, struct dm_cell_key
*key
, struct bio
*bio
,
244 struct dm_bio_prison_cell
**cell_result
)
247 struct dm_bio_prison_cell
*cell_prealloc
;
250 * Allocate a cell from the prison's mempool.
251 * This might block but it can't fail.
253 cell_prealloc
= dm_bio_prison_alloc_cell(pool
->prison
, GFP_NOIO
);
255 r
= dm_bio_detain(pool
->prison
, key
, bio
, cell_prealloc
, cell_result
);
258 * We reused an old cell; we can get rid of
261 dm_bio_prison_free_cell(pool
->prison
, cell_prealloc
);
266 static void cell_release(struct pool
*pool
,
267 struct dm_bio_prison_cell
*cell
,
268 struct bio_list
*bios
)
270 dm_cell_release(pool
->prison
, cell
, bios
);
271 dm_bio_prison_free_cell(pool
->prison
, cell
);
274 static void cell_release_no_holder(struct pool
*pool
,
275 struct dm_bio_prison_cell
*cell
,
276 struct bio_list
*bios
)
278 dm_cell_release_no_holder(pool
->prison
, cell
, bios
);
279 dm_bio_prison_free_cell(pool
->prison
, cell
);
282 static void cell_defer_no_holder_no_free(struct thin_c
*tc
,
283 struct dm_bio_prison_cell
*cell
)
285 struct pool
*pool
= tc
->pool
;
288 spin_lock_irqsave(&pool
->lock
, flags
);
289 dm_cell_release_no_holder(pool
->prison
, cell
, &pool
->deferred_bios
);
290 spin_unlock_irqrestore(&pool
->lock
, flags
);
295 static void cell_error(struct pool
*pool
,
296 struct dm_bio_prison_cell
*cell
)
298 dm_cell_error(pool
->prison
, cell
);
299 dm_bio_prison_free_cell(pool
->prison
, cell
);
302 /*----------------------------------------------------------------*/
305 * A global list of pools that uses a struct mapped_device as a key.
307 static struct dm_thin_pool_table
{
309 struct list_head pools
;
310 } dm_thin_pool_table
;
312 static void pool_table_init(void)
314 mutex_init(&dm_thin_pool_table
.mutex
);
315 INIT_LIST_HEAD(&dm_thin_pool_table
.pools
);
318 static void __pool_table_insert(struct pool
*pool
)
320 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
321 list_add(&pool
->list
, &dm_thin_pool_table
.pools
);
324 static void __pool_table_remove(struct pool
*pool
)
326 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
327 list_del(&pool
->list
);
330 static struct pool
*__pool_table_lookup(struct mapped_device
*md
)
332 struct pool
*pool
= NULL
, *tmp
;
334 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
336 list_for_each_entry(tmp
, &dm_thin_pool_table
.pools
, list
) {
337 if (tmp
->pool_md
== md
) {
346 static struct pool
*__pool_table_lookup_metadata_dev(struct block_device
*md_dev
)
348 struct pool
*pool
= NULL
, *tmp
;
350 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
352 list_for_each_entry(tmp
, &dm_thin_pool_table
.pools
, list
) {
353 if (tmp
->md_dev
== md_dev
) {
362 /*----------------------------------------------------------------*/
364 struct dm_thin_endio_hook
{
366 struct dm_deferred_entry
*shared_read_entry
;
367 struct dm_deferred_entry
*all_io_entry
;
368 struct dm_thin_new_mapping
*overwrite_mapping
;
371 static void __requeue_bio_list(struct thin_c
*tc
, struct bio_list
*master
)
374 struct bio_list bios
;
376 bio_list_init(&bios
);
377 bio_list_merge(&bios
, master
);
378 bio_list_init(master
);
380 while ((bio
= bio_list_pop(&bios
))) {
381 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
384 bio_endio(bio
, DM_ENDIO_REQUEUE
);
386 bio_list_add(master
, bio
);
390 static void requeue_io(struct thin_c
*tc
)
392 struct pool
*pool
= tc
->pool
;
395 spin_lock_irqsave(&pool
->lock
, flags
);
396 __requeue_bio_list(tc
, &pool
->deferred_bios
);
397 __requeue_bio_list(tc
, &pool
->retry_on_resume_list
);
398 spin_unlock_irqrestore(&pool
->lock
, flags
);
402 * This section of code contains the logic for processing a thin device's IO.
403 * Much of the code depends on pool object resources (lists, workqueues, etc)
404 * but most is exclusively called from the thin target rather than the thin-pool
408 static bool block_size_is_power_of_two(struct pool
*pool
)
410 return pool
->sectors_per_block_shift
>= 0;
413 static dm_block_t
get_bio_block(struct thin_c
*tc
, struct bio
*bio
)
415 struct pool
*pool
= tc
->pool
;
416 sector_t block_nr
= bio
->bi_sector
;
418 if (block_size_is_power_of_two(pool
))
419 block_nr
>>= pool
->sectors_per_block_shift
;
421 (void) sector_div(block_nr
, pool
->sectors_per_block
);
426 static void remap(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
)
428 struct pool
*pool
= tc
->pool
;
429 sector_t bi_sector
= bio
->bi_sector
;
431 bio
->bi_bdev
= tc
->pool_dev
->bdev
;
432 if (block_size_is_power_of_two(pool
))
433 bio
->bi_sector
= (block
<< pool
->sectors_per_block_shift
) |
434 (bi_sector
& (pool
->sectors_per_block
- 1));
436 bio
->bi_sector
= (block
* pool
->sectors_per_block
) +
437 sector_div(bi_sector
, pool
->sectors_per_block
);
440 static void remap_to_origin(struct thin_c
*tc
, struct bio
*bio
)
442 bio
->bi_bdev
= tc
->origin_dev
->bdev
;
445 static int bio_triggers_commit(struct thin_c
*tc
, struct bio
*bio
)
447 return (bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
)) &&
448 dm_thin_changed_this_transaction(tc
->td
);
451 static void inc_all_io_entry(struct pool
*pool
, struct bio
*bio
)
453 struct dm_thin_endio_hook
*h
;
455 if (bio
->bi_rw
& REQ_DISCARD
)
458 h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
459 h
->all_io_entry
= dm_deferred_entry_inc(pool
->all_io_ds
);
462 static void issue(struct thin_c
*tc
, struct bio
*bio
)
464 struct pool
*pool
= tc
->pool
;
467 if (!bio_triggers_commit(tc
, bio
)) {
468 generic_make_request(bio
);
473 * Complete bio with an error if earlier I/O caused changes to
474 * the metadata that can't be committed e.g, due to I/O errors
475 * on the metadata device.
477 if (dm_thin_aborted_changes(tc
->td
)) {
483 * Batch together any bios that trigger commits and then issue a
484 * single commit for them in process_deferred_bios().
486 spin_lock_irqsave(&pool
->lock
, flags
);
487 bio_list_add(&pool
->deferred_flush_bios
, bio
);
488 spin_unlock_irqrestore(&pool
->lock
, flags
);
491 static void remap_to_origin_and_issue(struct thin_c
*tc
, struct bio
*bio
)
493 remap_to_origin(tc
, bio
);
497 static void remap_and_issue(struct thin_c
*tc
, struct bio
*bio
,
500 remap(tc
, bio
, block
);
504 /*----------------------------------------------------------------*/
507 * Bio endio functions.
509 struct dm_thin_new_mapping
{
510 struct list_head list
;
514 unsigned pass_discard
:1;
517 dm_block_t virt_block
;
518 dm_block_t data_block
;
519 struct dm_bio_prison_cell
*cell
, *cell2
;
523 * If the bio covers the whole area of a block then we can avoid
524 * zeroing or copying. Instead this bio is hooked. The bio will
525 * still be in the cell, so care has to be taken to avoid issuing
529 bio_end_io_t
*saved_bi_end_io
;
532 static void __maybe_add_mapping(struct dm_thin_new_mapping
*m
)
534 struct pool
*pool
= m
->tc
->pool
;
536 if (m
->quiesced
&& m
->prepared
) {
537 list_add(&m
->list
, &pool
->prepared_mappings
);
542 static void copy_complete(int read_err
, unsigned long write_err
, void *context
)
545 struct dm_thin_new_mapping
*m
= context
;
546 struct pool
*pool
= m
->tc
->pool
;
548 m
->err
= read_err
|| write_err
? -EIO
: 0;
550 spin_lock_irqsave(&pool
->lock
, flags
);
552 __maybe_add_mapping(m
);
553 spin_unlock_irqrestore(&pool
->lock
, flags
);
556 static void overwrite_endio(struct bio
*bio
, int err
)
559 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
560 struct dm_thin_new_mapping
*m
= h
->overwrite_mapping
;
561 struct pool
*pool
= m
->tc
->pool
;
565 spin_lock_irqsave(&pool
->lock
, flags
);
567 __maybe_add_mapping(m
);
568 spin_unlock_irqrestore(&pool
->lock
, flags
);
571 /*----------------------------------------------------------------*/
578 * Prepared mapping jobs.
582 * This sends the bios in the cell back to the deferred_bios list.
584 static void cell_defer(struct thin_c
*tc
, struct dm_bio_prison_cell
*cell
)
586 struct pool
*pool
= tc
->pool
;
589 spin_lock_irqsave(&pool
->lock
, flags
);
590 cell_release(pool
, cell
, &pool
->deferred_bios
);
591 spin_unlock_irqrestore(&tc
->pool
->lock
, flags
);
597 * Same as cell_defer above, except it omits the original holder of the cell.
599 static void cell_defer_no_holder(struct thin_c
*tc
, struct dm_bio_prison_cell
*cell
)
601 struct pool
*pool
= tc
->pool
;
604 spin_lock_irqsave(&pool
->lock
, flags
);
605 cell_release_no_holder(pool
, cell
, &pool
->deferred_bios
);
606 spin_unlock_irqrestore(&pool
->lock
, flags
);
611 static void process_prepared_mapping_fail(struct dm_thin_new_mapping
*m
)
614 m
->bio
->bi_end_io
= m
->saved_bi_end_io
;
615 cell_error(m
->tc
->pool
, m
->cell
);
617 mempool_free(m
, m
->tc
->pool
->mapping_pool
);
620 static void process_prepared_mapping(struct dm_thin_new_mapping
*m
)
622 struct thin_c
*tc
= m
->tc
;
623 struct pool
*pool
= tc
->pool
;
629 bio
->bi_end_io
= m
->saved_bi_end_io
;
632 cell_error(pool
, m
->cell
);
637 * Commit the prepared block into the mapping btree.
638 * Any I/O for this block arriving after this point will get
639 * remapped to it directly.
641 r
= dm_thin_insert_block(tc
->td
, m
->virt_block
, m
->data_block
);
643 DMERR_LIMIT("dm_thin_insert_block() failed");
644 cell_error(pool
, m
->cell
);
649 * Release any bios held while the block was being provisioned.
650 * If we are processing a write bio that completely covers the block,
651 * we already processed it so can ignore it now when processing
652 * the bios in the cell.
655 cell_defer_no_holder(tc
, m
->cell
);
658 cell_defer(tc
, m
->cell
);
662 mempool_free(m
, pool
->mapping_pool
);
665 static void process_prepared_discard_fail(struct dm_thin_new_mapping
*m
)
667 struct thin_c
*tc
= m
->tc
;
669 bio_io_error(m
->bio
);
670 cell_defer_no_holder(tc
, m
->cell
);
671 cell_defer_no_holder(tc
, m
->cell2
);
672 mempool_free(m
, tc
->pool
->mapping_pool
);
675 static void process_prepared_discard_passdown(struct dm_thin_new_mapping
*m
)
677 struct thin_c
*tc
= m
->tc
;
679 inc_all_io_entry(tc
->pool
, m
->bio
);
680 cell_defer_no_holder(tc
, m
->cell
);
681 cell_defer_no_holder(tc
, m
->cell2
);
684 remap_and_issue(tc
, m
->bio
, m
->data_block
);
686 bio_endio(m
->bio
, 0);
688 mempool_free(m
, tc
->pool
->mapping_pool
);
691 static void process_prepared_discard(struct dm_thin_new_mapping
*m
)
694 struct thin_c
*tc
= m
->tc
;
696 r
= dm_thin_remove_block(tc
->td
, m
->virt_block
);
698 DMERR_LIMIT("dm_thin_remove_block() failed");
700 process_prepared_discard_passdown(m
);
703 static void process_prepared(struct pool
*pool
, struct list_head
*head
,
704 process_mapping_fn
*fn
)
707 struct list_head maps
;
708 struct dm_thin_new_mapping
*m
, *tmp
;
710 INIT_LIST_HEAD(&maps
);
711 spin_lock_irqsave(&pool
->lock
, flags
);
712 list_splice_init(head
, &maps
);
713 spin_unlock_irqrestore(&pool
->lock
, flags
);
715 list_for_each_entry_safe(m
, tmp
, &maps
, list
)
722 static int io_overlaps_block(struct pool
*pool
, struct bio
*bio
)
724 return bio
->bi_size
== (pool
->sectors_per_block
<< SECTOR_SHIFT
);
727 static int io_overwrites_block(struct pool
*pool
, struct bio
*bio
)
729 return (bio_data_dir(bio
) == WRITE
) &&
730 io_overlaps_block(pool
, bio
);
733 static void save_and_set_endio(struct bio
*bio
, bio_end_io_t
**save
,
736 *save
= bio
->bi_end_io
;
740 static int ensure_next_mapping(struct pool
*pool
)
742 if (pool
->next_mapping
)
745 pool
->next_mapping
= mempool_alloc(pool
->mapping_pool
, GFP_ATOMIC
);
747 return pool
->next_mapping
? 0 : -ENOMEM
;
750 static struct dm_thin_new_mapping
*get_next_mapping(struct pool
*pool
)
752 struct dm_thin_new_mapping
*r
= pool
->next_mapping
;
754 BUG_ON(!pool
->next_mapping
);
756 pool
->next_mapping
= NULL
;
761 static void schedule_copy(struct thin_c
*tc
, dm_block_t virt_block
,
762 struct dm_dev
*origin
, dm_block_t data_origin
,
763 dm_block_t data_dest
,
764 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
767 struct pool
*pool
= tc
->pool
;
768 struct dm_thin_new_mapping
*m
= get_next_mapping(pool
);
770 INIT_LIST_HEAD(&m
->list
);
774 m
->virt_block
= virt_block
;
775 m
->data_block
= data_dest
;
780 if (!dm_deferred_set_add_work(pool
->shared_read_ds
, &m
->list
))
784 * IO to pool_dev remaps to the pool target's data_dev.
786 * If the whole block of data is being overwritten, we can issue the
787 * bio immediately. Otherwise we use kcopyd to clone the data first.
789 if (io_overwrites_block(pool
, bio
)) {
790 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
792 h
->overwrite_mapping
= m
;
794 save_and_set_endio(bio
, &m
->saved_bi_end_io
, overwrite_endio
);
795 inc_all_io_entry(pool
, bio
);
796 remap_and_issue(tc
, bio
, data_dest
);
798 struct dm_io_region from
, to
;
800 from
.bdev
= origin
->bdev
;
801 from
.sector
= data_origin
* pool
->sectors_per_block
;
802 from
.count
= pool
->sectors_per_block
;
804 to
.bdev
= tc
->pool_dev
->bdev
;
805 to
.sector
= data_dest
* pool
->sectors_per_block
;
806 to
.count
= pool
->sectors_per_block
;
808 r
= dm_kcopyd_copy(pool
->copier
, &from
, 1, &to
,
809 0, copy_complete
, m
);
811 mempool_free(m
, pool
->mapping_pool
);
812 DMERR_LIMIT("dm_kcopyd_copy() failed");
813 cell_error(pool
, cell
);
818 static void schedule_internal_copy(struct thin_c
*tc
, dm_block_t virt_block
,
819 dm_block_t data_origin
, dm_block_t data_dest
,
820 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
822 schedule_copy(tc
, virt_block
, tc
->pool_dev
,
823 data_origin
, data_dest
, cell
, bio
);
826 static void schedule_external_copy(struct thin_c
*tc
, dm_block_t virt_block
,
827 dm_block_t data_dest
,
828 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
830 schedule_copy(tc
, virt_block
, tc
->origin_dev
,
831 virt_block
, data_dest
, cell
, bio
);
834 static void schedule_zero(struct thin_c
*tc
, dm_block_t virt_block
,
835 dm_block_t data_block
, struct dm_bio_prison_cell
*cell
,
838 struct pool
*pool
= tc
->pool
;
839 struct dm_thin_new_mapping
*m
= get_next_mapping(pool
);
841 INIT_LIST_HEAD(&m
->list
);
845 m
->virt_block
= virt_block
;
846 m
->data_block
= data_block
;
852 * If the whole block of data is being overwritten or we are not
853 * zeroing pre-existing data, we can issue the bio immediately.
854 * Otherwise we use kcopyd to zero the data first.
856 if (!pool
->pf
.zero_new_blocks
)
857 process_prepared_mapping(m
);
859 else if (io_overwrites_block(pool
, bio
)) {
860 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
862 h
->overwrite_mapping
= m
;
864 save_and_set_endio(bio
, &m
->saved_bi_end_io
, overwrite_endio
);
865 inc_all_io_entry(pool
, bio
);
866 remap_and_issue(tc
, bio
, data_block
);
869 struct dm_io_region to
;
871 to
.bdev
= tc
->pool_dev
->bdev
;
872 to
.sector
= data_block
* pool
->sectors_per_block
;
873 to
.count
= pool
->sectors_per_block
;
875 r
= dm_kcopyd_zero(pool
->copier
, 1, &to
, 0, copy_complete
, m
);
877 mempool_free(m
, pool
->mapping_pool
);
878 DMERR_LIMIT("dm_kcopyd_zero() failed");
879 cell_error(pool
, cell
);
884 static int commit(struct pool
*pool
)
888 r
= dm_pool_commit_metadata(pool
->pmd
);
890 DMERR_LIMIT("commit failed: error = %d", r
);
896 * A non-zero return indicates read_only or fail_io mode.
897 * Many callers don't care about the return value.
899 static int commit_or_fallback(struct pool
*pool
)
903 if (get_pool_mode(pool
) != PM_WRITE
)
908 set_pool_mode(pool
, PM_READ_ONLY
);
913 static int alloc_data_block(struct thin_c
*tc
, dm_block_t
*result
)
916 dm_block_t free_blocks
;
918 struct pool
*pool
= tc
->pool
;
920 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
924 if (free_blocks
<= pool
->low_water_blocks
&& !pool
->low_water_triggered
) {
925 DMWARN("%s: reached low water mark, sending event.",
926 dm_device_name(pool
->pool_md
));
927 spin_lock_irqsave(&pool
->lock
, flags
);
928 pool
->low_water_triggered
= 1;
929 spin_unlock_irqrestore(&pool
->lock
, flags
);
930 dm_table_event(pool
->ti
->table
);
934 if (pool
->no_free_space
)
938 * Try to commit to see if that will free up some
941 (void) commit_or_fallback(pool
);
943 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
948 * If we still have no space we set a flag to avoid
949 * doing all this checking and return -ENOSPC.
952 DMWARN("%s: no free space available.",
953 dm_device_name(pool
->pool_md
));
954 spin_lock_irqsave(&pool
->lock
, flags
);
955 pool
->no_free_space
= 1;
956 spin_unlock_irqrestore(&pool
->lock
, flags
);
962 r
= dm_pool_alloc_data_block(pool
->pmd
, result
);
970 * If we have run out of space, queue bios until the device is
971 * resumed, presumably after having been reloaded with more space.
973 static void retry_on_resume(struct bio
*bio
)
975 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
976 struct thin_c
*tc
= h
->tc
;
977 struct pool
*pool
= tc
->pool
;
980 spin_lock_irqsave(&pool
->lock
, flags
);
981 bio_list_add(&pool
->retry_on_resume_list
, bio
);
982 spin_unlock_irqrestore(&pool
->lock
, flags
);
985 static void no_space(struct pool
*pool
, struct dm_bio_prison_cell
*cell
)
988 struct bio_list bios
;
990 bio_list_init(&bios
);
991 cell_release(pool
, cell
, &bios
);
993 while ((bio
= bio_list_pop(&bios
)))
994 retry_on_resume(bio
);
997 static void process_discard(struct thin_c
*tc
, struct bio
*bio
)
1000 unsigned long flags
;
1001 struct pool
*pool
= tc
->pool
;
1002 struct dm_bio_prison_cell
*cell
, *cell2
;
1003 struct dm_cell_key key
, key2
;
1004 dm_block_t block
= get_bio_block(tc
, bio
);
1005 struct dm_thin_lookup_result lookup_result
;
1006 struct dm_thin_new_mapping
*m
;
1008 build_virtual_key(tc
->td
, block
, &key
);
1009 if (bio_detain(tc
->pool
, &key
, bio
, &cell
))
1012 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1016 * Check nobody is fiddling with this pool block. This can
1017 * happen if someone's in the process of breaking sharing
1020 build_data_key(tc
->td
, lookup_result
.block
, &key2
);
1021 if (bio_detain(tc
->pool
, &key2
, bio
, &cell2
)) {
1022 cell_defer_no_holder(tc
, cell
);
1026 if (io_overlaps_block(pool
, bio
)) {
1028 * IO may still be going to the destination block. We must
1029 * quiesce before we can do the removal.
1031 m
= get_next_mapping(pool
);
1033 m
->pass_discard
= (!lookup_result
.shared
) && pool
->pf
.discard_passdown
;
1034 m
->virt_block
= block
;
1035 m
->data_block
= lookup_result
.block
;
1041 if (!dm_deferred_set_add_work(pool
->all_io_ds
, &m
->list
)) {
1042 spin_lock_irqsave(&pool
->lock
, flags
);
1043 list_add(&m
->list
, &pool
->prepared_discards
);
1044 spin_unlock_irqrestore(&pool
->lock
, flags
);
1048 inc_all_io_entry(pool
, bio
);
1049 cell_defer_no_holder(tc
, cell
);
1050 cell_defer_no_holder(tc
, cell2
);
1053 * The DM core makes sure that the discard doesn't span
1054 * a block boundary. So we submit the discard of a
1055 * partial block appropriately.
1057 if ((!lookup_result
.shared
) && pool
->pf
.discard_passdown
)
1058 remap_and_issue(tc
, bio
, lookup_result
.block
);
1066 * It isn't provisioned, just forget it.
1068 cell_defer_no_holder(tc
, cell
);
1073 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1075 cell_defer_no_holder(tc
, cell
);
1081 static void break_sharing(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1082 struct dm_cell_key
*key
,
1083 struct dm_thin_lookup_result
*lookup_result
,
1084 struct dm_bio_prison_cell
*cell
)
1087 dm_block_t data_block
;
1089 r
= alloc_data_block(tc
, &data_block
);
1092 schedule_internal_copy(tc
, block
, lookup_result
->block
,
1093 data_block
, cell
, bio
);
1097 no_space(tc
->pool
, cell
);
1101 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1103 cell_error(tc
->pool
, cell
);
1108 static void process_shared_bio(struct thin_c
*tc
, struct bio
*bio
,
1110 struct dm_thin_lookup_result
*lookup_result
)
1112 struct dm_bio_prison_cell
*cell
;
1113 struct pool
*pool
= tc
->pool
;
1114 struct dm_cell_key key
;
1117 * If cell is already occupied, then sharing is already in the process
1118 * of being broken so we have nothing further to do here.
1120 build_data_key(tc
->td
, lookup_result
->block
, &key
);
1121 if (bio_detain(pool
, &key
, bio
, &cell
))
1124 if (bio_data_dir(bio
) == WRITE
&& bio
->bi_size
)
1125 break_sharing(tc
, bio
, block
, &key
, lookup_result
, cell
);
1127 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1129 h
->shared_read_entry
= dm_deferred_entry_inc(pool
->shared_read_ds
);
1130 inc_all_io_entry(pool
, bio
);
1131 cell_defer_no_holder(tc
, cell
);
1133 remap_and_issue(tc
, bio
, lookup_result
->block
);
1137 static void provision_block(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1138 struct dm_bio_prison_cell
*cell
)
1141 dm_block_t data_block
;
1142 struct pool
*pool
= tc
->pool
;
1145 * Remap empty bios (flushes) immediately, without provisioning.
1147 if (!bio
->bi_size
) {
1148 inc_all_io_entry(pool
, bio
);
1149 cell_defer_no_holder(tc
, cell
);
1151 remap_and_issue(tc
, bio
, 0);
1156 * Fill read bios with zeroes and complete them immediately.
1158 if (bio_data_dir(bio
) == READ
) {
1160 cell_defer_no_holder(tc
, cell
);
1165 r
= alloc_data_block(tc
, &data_block
);
1169 schedule_external_copy(tc
, block
, data_block
, cell
, bio
);
1171 schedule_zero(tc
, block
, data_block
, cell
, bio
);
1175 no_space(pool
, cell
);
1179 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1181 set_pool_mode(pool
, PM_READ_ONLY
);
1182 cell_error(pool
, cell
);
1187 static void process_bio(struct thin_c
*tc
, struct bio
*bio
)
1190 struct pool
*pool
= tc
->pool
;
1191 dm_block_t block
= get_bio_block(tc
, bio
);
1192 struct dm_bio_prison_cell
*cell
;
1193 struct dm_cell_key key
;
1194 struct dm_thin_lookup_result lookup_result
;
1197 * If cell is already occupied, then the block is already
1198 * being provisioned so we have nothing further to do here.
1200 build_virtual_key(tc
->td
, block
, &key
);
1201 if (bio_detain(pool
, &key
, bio
, &cell
))
1204 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1207 if (lookup_result
.shared
) {
1208 process_shared_bio(tc
, bio
, block
, &lookup_result
);
1209 cell_defer_no_holder(tc
, cell
); /* FIXME: pass this cell into process_shared? */
1211 inc_all_io_entry(pool
, bio
);
1212 cell_defer_no_holder(tc
, cell
);
1214 remap_and_issue(tc
, bio
, lookup_result
.block
);
1219 if (bio_data_dir(bio
) == READ
&& tc
->origin_dev
) {
1220 inc_all_io_entry(pool
, bio
);
1221 cell_defer_no_holder(tc
, cell
);
1223 remap_to_origin_and_issue(tc
, bio
);
1225 provision_block(tc
, bio
, block
, cell
);
1229 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1231 cell_defer_no_holder(tc
, cell
);
1237 static void process_bio_read_only(struct thin_c
*tc
, struct bio
*bio
)
1240 int rw
= bio_data_dir(bio
);
1241 dm_block_t block
= get_bio_block(tc
, bio
);
1242 struct dm_thin_lookup_result lookup_result
;
1244 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1247 if (lookup_result
.shared
&& (rw
== WRITE
) && bio
->bi_size
)
1250 inc_all_io_entry(tc
->pool
, bio
);
1251 remap_and_issue(tc
, bio
, lookup_result
.block
);
1261 if (tc
->origin_dev
) {
1262 inc_all_io_entry(tc
->pool
, bio
);
1263 remap_to_origin_and_issue(tc
, bio
);
1272 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1279 static void process_bio_fail(struct thin_c
*tc
, struct bio
*bio
)
1284 static int need_commit_due_to_time(struct pool
*pool
)
1286 return jiffies
< pool
->last_commit_jiffies
||
1287 jiffies
> pool
->last_commit_jiffies
+ COMMIT_PERIOD
;
1290 static void process_deferred_bios(struct pool
*pool
)
1292 unsigned long flags
;
1294 struct bio_list bios
;
1296 bio_list_init(&bios
);
1298 spin_lock_irqsave(&pool
->lock
, flags
);
1299 bio_list_merge(&bios
, &pool
->deferred_bios
);
1300 bio_list_init(&pool
->deferred_bios
);
1301 spin_unlock_irqrestore(&pool
->lock
, flags
);
1303 while ((bio
= bio_list_pop(&bios
))) {
1304 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1305 struct thin_c
*tc
= h
->tc
;
1308 * If we've got no free new_mapping structs, and processing
1309 * this bio might require one, we pause until there are some
1310 * prepared mappings to process.
1312 if (ensure_next_mapping(pool
)) {
1313 spin_lock_irqsave(&pool
->lock
, flags
);
1314 bio_list_merge(&pool
->deferred_bios
, &bios
);
1315 spin_unlock_irqrestore(&pool
->lock
, flags
);
1320 if (bio
->bi_rw
& REQ_DISCARD
)
1321 pool
->process_discard(tc
, bio
);
1323 pool
->process_bio(tc
, bio
);
1327 * If there are any deferred flush bios, we must commit
1328 * the metadata before issuing them.
1330 bio_list_init(&bios
);
1331 spin_lock_irqsave(&pool
->lock
, flags
);
1332 bio_list_merge(&bios
, &pool
->deferred_flush_bios
);
1333 bio_list_init(&pool
->deferred_flush_bios
);
1334 spin_unlock_irqrestore(&pool
->lock
, flags
);
1336 if (bio_list_empty(&bios
) && !need_commit_due_to_time(pool
))
1339 if (commit_or_fallback(pool
)) {
1340 while ((bio
= bio_list_pop(&bios
)))
1344 pool
->last_commit_jiffies
= jiffies
;
1346 while ((bio
= bio_list_pop(&bios
)))
1347 generic_make_request(bio
);
1350 static void do_worker(struct work_struct
*ws
)
1352 struct pool
*pool
= container_of(ws
, struct pool
, worker
);
1354 process_prepared(pool
, &pool
->prepared_mappings
, &pool
->process_prepared_mapping
);
1355 process_prepared(pool
, &pool
->prepared_discards
, &pool
->process_prepared_discard
);
1356 process_deferred_bios(pool
);
1360 * We want to commit periodically so that not too much
1361 * unwritten data builds up.
1363 static void do_waker(struct work_struct
*ws
)
1365 struct pool
*pool
= container_of(to_delayed_work(ws
), struct pool
, waker
);
1367 queue_delayed_work(pool
->wq
, &pool
->waker
, COMMIT_PERIOD
);
1370 /*----------------------------------------------------------------*/
1372 static enum pool_mode
get_pool_mode(struct pool
*pool
)
1374 return pool
->pf
.mode
;
1377 static void set_pool_mode(struct pool
*pool
, enum pool_mode mode
)
1381 pool
->pf
.mode
= mode
;
1385 DMERR("switching pool to failure mode");
1386 pool
->process_bio
= process_bio_fail
;
1387 pool
->process_discard
= process_bio_fail
;
1388 pool
->process_prepared_mapping
= process_prepared_mapping_fail
;
1389 pool
->process_prepared_discard
= process_prepared_discard_fail
;
1393 DMERR("switching pool to read-only mode");
1394 r
= dm_pool_abort_metadata(pool
->pmd
);
1396 DMERR("aborting transaction failed");
1397 set_pool_mode(pool
, PM_FAIL
);
1399 dm_pool_metadata_read_only(pool
->pmd
);
1400 pool
->process_bio
= process_bio_read_only
;
1401 pool
->process_discard
= process_discard
;
1402 pool
->process_prepared_mapping
= process_prepared_mapping_fail
;
1403 pool
->process_prepared_discard
= process_prepared_discard_passdown
;
1408 pool
->process_bio
= process_bio
;
1409 pool
->process_discard
= process_discard
;
1410 pool
->process_prepared_mapping
= process_prepared_mapping
;
1411 pool
->process_prepared_discard
= process_prepared_discard
;
1416 /*----------------------------------------------------------------*/
1419 * Mapping functions.
1423 * Called only while mapping a thin bio to hand it over to the workqueue.
1425 static void thin_defer_bio(struct thin_c
*tc
, struct bio
*bio
)
1427 unsigned long flags
;
1428 struct pool
*pool
= tc
->pool
;
1430 spin_lock_irqsave(&pool
->lock
, flags
);
1431 bio_list_add(&pool
->deferred_bios
, bio
);
1432 spin_unlock_irqrestore(&pool
->lock
, flags
);
1437 static void thin_hook_bio(struct thin_c
*tc
, struct bio
*bio
)
1439 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1442 h
->shared_read_entry
= NULL
;
1443 h
->all_io_entry
= NULL
;
1444 h
->overwrite_mapping
= NULL
;
1448 * Non-blocking function called from the thin target's map function.
1450 static int thin_bio_map(struct dm_target
*ti
, struct bio
*bio
)
1453 struct thin_c
*tc
= ti
->private;
1454 dm_block_t block
= get_bio_block(tc
, bio
);
1455 struct dm_thin_device
*td
= tc
->td
;
1456 struct dm_thin_lookup_result result
;
1457 struct dm_bio_prison_cell cell1
, cell2
;
1458 struct dm_bio_prison_cell
*cell_result
;
1459 struct dm_cell_key key
;
1461 thin_hook_bio(tc
, bio
);
1463 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
1465 return DM_MAPIO_SUBMITTED
;
1468 if (bio
->bi_rw
& (REQ_DISCARD
| REQ_FLUSH
| REQ_FUA
)) {
1469 thin_defer_bio(tc
, bio
);
1470 return DM_MAPIO_SUBMITTED
;
1473 r
= dm_thin_find_block(td
, block
, 0, &result
);
1476 * Note that we defer readahead too.
1480 if (unlikely(result
.shared
)) {
1482 * We have a race condition here between the
1483 * result.shared value returned by the lookup and
1484 * snapshot creation, which may cause new
1487 * To avoid this always quiesce the origin before
1488 * taking the snap. You want to do this anyway to
1489 * ensure a consistent application view
1492 * More distant ancestors are irrelevant. The
1493 * shared flag will be set in their case.
1495 thin_defer_bio(tc
, bio
);
1496 return DM_MAPIO_SUBMITTED
;
1499 build_virtual_key(tc
->td
, block
, &key
);
1500 if (dm_bio_detain(tc
->pool
->prison
, &key
, bio
, &cell1
, &cell_result
))
1501 return DM_MAPIO_SUBMITTED
;
1503 build_data_key(tc
->td
, result
.block
, &key
);
1504 if (dm_bio_detain(tc
->pool
->prison
, &key
, bio
, &cell2
, &cell_result
)) {
1505 cell_defer_no_holder_no_free(tc
, &cell1
);
1506 return DM_MAPIO_SUBMITTED
;
1509 inc_all_io_entry(tc
->pool
, bio
);
1510 cell_defer_no_holder_no_free(tc
, &cell2
);
1511 cell_defer_no_holder_no_free(tc
, &cell1
);
1513 remap(tc
, bio
, result
.block
);
1514 return DM_MAPIO_REMAPPED
;
1517 if (get_pool_mode(tc
->pool
) == PM_READ_ONLY
) {
1519 * This block isn't provisioned, and we have no way
1520 * of doing so. Just error it.
1523 return DM_MAPIO_SUBMITTED
;
1529 * In future, the failed dm_thin_find_block above could
1530 * provide the hint to load the metadata into cache.
1532 thin_defer_bio(tc
, bio
);
1533 return DM_MAPIO_SUBMITTED
;
1537 * Must always call bio_io_error on failure.
1538 * dm_thin_find_block can fail with -EINVAL if the
1539 * pool is switched to fail-io mode.
1542 return DM_MAPIO_SUBMITTED
;
1546 static int pool_is_congested(struct dm_target_callbacks
*cb
, int bdi_bits
)
1549 unsigned long flags
;
1550 struct pool_c
*pt
= container_of(cb
, struct pool_c
, callbacks
);
1552 spin_lock_irqsave(&pt
->pool
->lock
, flags
);
1553 r
= !bio_list_empty(&pt
->pool
->retry_on_resume_list
);
1554 spin_unlock_irqrestore(&pt
->pool
->lock
, flags
);
1557 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1558 r
= bdi_congested(&q
->backing_dev_info
, bdi_bits
);
1564 static void __requeue_bios(struct pool
*pool
)
1566 bio_list_merge(&pool
->deferred_bios
, &pool
->retry_on_resume_list
);
1567 bio_list_init(&pool
->retry_on_resume_list
);
1570 /*----------------------------------------------------------------
1571 * Binding of control targets to a pool object
1572 *--------------------------------------------------------------*/
1573 static bool data_dev_supports_discard(struct pool_c
*pt
)
1575 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1577 return q
&& blk_queue_discard(q
);
1580 static bool is_factor(sector_t block_size
, uint32_t n
)
1582 return !sector_div(block_size
, n
);
1586 * If discard_passdown was enabled verify that the data device
1587 * supports discards. Disable discard_passdown if not.
1589 static void disable_passdown_if_not_supported(struct pool_c
*pt
)
1591 struct pool
*pool
= pt
->pool
;
1592 struct block_device
*data_bdev
= pt
->data_dev
->bdev
;
1593 struct queue_limits
*data_limits
= &bdev_get_queue(data_bdev
)->limits
;
1594 sector_t block_size
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
1595 const char *reason
= NULL
;
1596 char buf
[BDEVNAME_SIZE
];
1598 if (!pt
->adjusted_pf
.discard_passdown
)
1601 if (!data_dev_supports_discard(pt
))
1602 reason
= "discard unsupported";
1604 else if (data_limits
->max_discard_sectors
< pool
->sectors_per_block
)
1605 reason
= "max discard sectors smaller than a block";
1607 else if (data_limits
->discard_granularity
> block_size
)
1608 reason
= "discard granularity larger than a block";
1610 else if (!is_factor(block_size
, data_limits
->discard_granularity
))
1611 reason
= "discard granularity not a factor of block size";
1614 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev
, buf
), reason
);
1615 pt
->adjusted_pf
.discard_passdown
= false;
1619 static int bind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1621 struct pool_c
*pt
= ti
->private;
1624 * We want to make sure that degraded pools are never upgraded.
1626 enum pool_mode old_mode
= pool
->pf
.mode
;
1627 enum pool_mode new_mode
= pt
->adjusted_pf
.mode
;
1629 if (old_mode
> new_mode
)
1630 new_mode
= old_mode
;
1633 pool
->low_water_blocks
= pt
->low_water_blocks
;
1634 pool
->pf
= pt
->adjusted_pf
;
1636 set_pool_mode(pool
, new_mode
);
1641 static void unbind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1647 /*----------------------------------------------------------------
1649 *--------------------------------------------------------------*/
1650 /* Initialize pool features. */
1651 static void pool_features_init(struct pool_features
*pf
)
1653 pf
->mode
= PM_WRITE
;
1654 pf
->zero_new_blocks
= true;
1655 pf
->discard_enabled
= true;
1656 pf
->discard_passdown
= true;
1659 static void __pool_destroy(struct pool
*pool
)
1661 __pool_table_remove(pool
);
1663 if (dm_pool_metadata_close(pool
->pmd
) < 0)
1664 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1666 dm_bio_prison_destroy(pool
->prison
);
1667 dm_kcopyd_client_destroy(pool
->copier
);
1670 destroy_workqueue(pool
->wq
);
1672 if (pool
->next_mapping
)
1673 mempool_free(pool
->next_mapping
, pool
->mapping_pool
);
1674 mempool_destroy(pool
->mapping_pool
);
1675 dm_deferred_set_destroy(pool
->shared_read_ds
);
1676 dm_deferred_set_destroy(pool
->all_io_ds
);
1680 static struct kmem_cache
*_new_mapping_cache
;
1682 static struct pool
*pool_create(struct mapped_device
*pool_md
,
1683 struct block_device
*metadata_dev
,
1684 unsigned long block_size
,
1685 int read_only
, char **error
)
1690 struct dm_pool_metadata
*pmd
;
1691 bool format_device
= read_only
? false : true;
1693 pmd
= dm_pool_metadata_open(metadata_dev
, block_size
, format_device
);
1695 *error
= "Error creating metadata object";
1696 return (struct pool
*)pmd
;
1699 pool
= kmalloc(sizeof(*pool
), GFP_KERNEL
);
1701 *error
= "Error allocating memory for pool";
1702 err_p
= ERR_PTR(-ENOMEM
);
1707 pool
->sectors_per_block
= block_size
;
1708 if (block_size
& (block_size
- 1))
1709 pool
->sectors_per_block_shift
= -1;
1711 pool
->sectors_per_block_shift
= __ffs(block_size
);
1712 pool
->low_water_blocks
= 0;
1713 pool_features_init(&pool
->pf
);
1714 pool
->prison
= dm_bio_prison_create(PRISON_CELLS
);
1715 if (!pool
->prison
) {
1716 *error
= "Error creating pool's bio prison";
1717 err_p
= ERR_PTR(-ENOMEM
);
1721 pool
->copier
= dm_kcopyd_client_create(&dm_kcopyd_throttle
);
1722 if (IS_ERR(pool
->copier
)) {
1723 r
= PTR_ERR(pool
->copier
);
1724 *error
= "Error creating pool's kcopyd client";
1726 goto bad_kcopyd_client
;
1730 * Create singlethreaded workqueue that will service all devices
1731 * that use this metadata.
1733 pool
->wq
= alloc_ordered_workqueue("dm-" DM_MSG_PREFIX
, WQ_MEM_RECLAIM
);
1735 *error
= "Error creating pool's workqueue";
1736 err_p
= ERR_PTR(-ENOMEM
);
1740 INIT_WORK(&pool
->worker
, do_worker
);
1741 INIT_DELAYED_WORK(&pool
->waker
, do_waker
);
1742 spin_lock_init(&pool
->lock
);
1743 bio_list_init(&pool
->deferred_bios
);
1744 bio_list_init(&pool
->deferred_flush_bios
);
1745 INIT_LIST_HEAD(&pool
->prepared_mappings
);
1746 INIT_LIST_HEAD(&pool
->prepared_discards
);
1747 pool
->low_water_triggered
= 0;
1748 pool
->no_free_space
= 0;
1749 bio_list_init(&pool
->retry_on_resume_list
);
1751 pool
->shared_read_ds
= dm_deferred_set_create();
1752 if (!pool
->shared_read_ds
) {
1753 *error
= "Error creating pool's shared read deferred set";
1754 err_p
= ERR_PTR(-ENOMEM
);
1755 goto bad_shared_read_ds
;
1758 pool
->all_io_ds
= dm_deferred_set_create();
1759 if (!pool
->all_io_ds
) {
1760 *error
= "Error creating pool's all io deferred set";
1761 err_p
= ERR_PTR(-ENOMEM
);
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
->ref_count
= 1;
1775 pool
->last_commit_jiffies
= jiffies
;
1776 pool
->pool_md
= pool_md
;
1777 pool
->md_dev
= metadata_dev
;
1778 __pool_table_insert(pool
);
1783 dm_deferred_set_destroy(pool
->all_io_ds
);
1785 dm_deferred_set_destroy(pool
->shared_read_ds
);
1787 destroy_workqueue(pool
->wq
);
1789 dm_kcopyd_client_destroy(pool
->copier
);
1791 dm_bio_prison_destroy(pool
->prison
);
1795 if (dm_pool_metadata_close(pmd
))
1796 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1801 static void __pool_inc(struct pool
*pool
)
1803 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1807 static void __pool_dec(struct pool
*pool
)
1809 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1810 BUG_ON(!pool
->ref_count
);
1811 if (!--pool
->ref_count
)
1812 __pool_destroy(pool
);
1815 static struct pool
*__pool_find(struct mapped_device
*pool_md
,
1816 struct block_device
*metadata_dev
,
1817 unsigned long block_size
, int read_only
,
1818 char **error
, int *created
)
1820 struct pool
*pool
= __pool_table_lookup_metadata_dev(metadata_dev
);
1823 if (pool
->pool_md
!= pool_md
) {
1824 *error
= "metadata device already in use by a pool";
1825 return ERR_PTR(-EBUSY
);
1830 pool
= __pool_table_lookup(pool_md
);
1832 if (pool
->md_dev
!= metadata_dev
) {
1833 *error
= "different pool cannot replace a pool";
1834 return ERR_PTR(-EINVAL
);
1839 pool
= pool_create(pool_md
, metadata_dev
, block_size
, read_only
, error
);
1847 /*----------------------------------------------------------------
1848 * Pool target methods
1849 *--------------------------------------------------------------*/
1850 static void pool_dtr(struct dm_target
*ti
)
1852 struct pool_c
*pt
= ti
->private;
1854 mutex_lock(&dm_thin_pool_table
.mutex
);
1856 unbind_control_target(pt
->pool
, ti
);
1857 __pool_dec(pt
->pool
);
1858 dm_put_device(ti
, pt
->metadata_dev
);
1859 dm_put_device(ti
, pt
->data_dev
);
1862 mutex_unlock(&dm_thin_pool_table
.mutex
);
1865 static int parse_pool_features(struct dm_arg_set
*as
, struct pool_features
*pf
,
1866 struct dm_target
*ti
)
1870 const char *arg_name
;
1872 static struct dm_arg _args
[] = {
1873 {0, 3, "Invalid number of pool feature arguments"},
1877 * No feature arguments supplied.
1882 r
= dm_read_arg_group(_args
, as
, &argc
, &ti
->error
);
1886 while (argc
&& !r
) {
1887 arg_name
= dm_shift_arg(as
);
1890 if (!strcasecmp(arg_name
, "skip_block_zeroing"))
1891 pf
->zero_new_blocks
= false;
1893 else if (!strcasecmp(arg_name
, "ignore_discard"))
1894 pf
->discard_enabled
= false;
1896 else if (!strcasecmp(arg_name
, "no_discard_passdown"))
1897 pf
->discard_passdown
= false;
1899 else if (!strcasecmp(arg_name
, "read_only"))
1900 pf
->mode
= PM_READ_ONLY
;
1903 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 block_size
& (DATA_DEV_BLOCK_SIZE_MIN_SECTORS
- 1)) {
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
, pf
.mode
== PM_READ_ONLY
, &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
;
2022 pt
->adjusted_pf
= pt
->requested_pf
= pf
;
2023 ti
->num_flush_bios
= 1;
2026 * Only need to enable discards if the pool should pass
2027 * them down to the data device. The thin device's discard
2028 * processing will cause mappings to be removed from the btree.
2030 if (pf
.discard_enabled
&& pf
.discard_passdown
) {
2031 ti
->num_discard_bios
= 1;
2034 * Setting 'discards_supported' circumvents the normal
2035 * stacking of discard limits (this keeps the pool and
2036 * thin devices' discard limits consistent).
2038 ti
->discards_supported
= true;
2039 ti
->discard_zeroes_data_unsupported
= true;
2043 pt
->callbacks
.congested_fn
= pool_is_congested
;
2044 dm_table_add_target_callbacks(ti
->table
, &pt
->callbacks
);
2046 mutex_unlock(&dm_thin_pool_table
.mutex
);
2055 dm_put_device(ti
, data_dev
);
2057 dm_put_device(ti
, metadata_dev
);
2059 mutex_unlock(&dm_thin_pool_table
.mutex
);
2064 static int pool_map(struct dm_target
*ti
, struct bio
*bio
)
2067 struct pool_c
*pt
= ti
->private;
2068 struct pool
*pool
= pt
->pool
;
2069 unsigned long flags
;
2072 * As this is a singleton target, ti->begin is always zero.
2074 spin_lock_irqsave(&pool
->lock
, flags
);
2075 bio
->bi_bdev
= pt
->data_dev
->bdev
;
2076 r
= DM_MAPIO_REMAPPED
;
2077 spin_unlock_irqrestore(&pool
->lock
, flags
);
2083 * Retrieves the number of blocks of the data device from
2084 * the superblock and compares it to the actual device size,
2085 * thus resizing the data device in case it has grown.
2087 * This both copes with opening preallocated data devices in the ctr
2088 * being followed by a resume
2090 * calling the resume method individually after userspace has
2091 * grown the data device in reaction to a table event.
2093 static int pool_preresume(struct dm_target
*ti
)
2096 struct pool_c
*pt
= ti
->private;
2097 struct pool
*pool
= pt
->pool
;
2098 sector_t data_size
= ti
->len
;
2099 dm_block_t sb_data_size
;
2102 * Take control of the pool object.
2104 r
= bind_control_target(pool
, ti
);
2108 (void) sector_div(data_size
, pool
->sectors_per_block
);
2110 r
= dm_pool_get_data_dev_size(pool
->pmd
, &sb_data_size
);
2112 DMERR("failed to retrieve data device size");
2116 if (data_size
< sb_data_size
) {
2117 DMERR("pool target too small, is %llu blocks (expected %llu)",
2118 (unsigned long long)data_size
, sb_data_size
);
2121 } else if (data_size
> sb_data_size
) {
2122 r
= dm_pool_resize_data_dev(pool
->pmd
, data_size
);
2124 DMERR("failed to resize data device");
2125 /* FIXME Stricter than necessary: Rollback transaction instead here */
2126 set_pool_mode(pool
, PM_READ_ONLY
);
2130 (void) commit_or_fallback(pool
);
2136 static void pool_resume(struct dm_target
*ti
)
2138 struct pool_c
*pt
= ti
->private;
2139 struct pool
*pool
= pt
->pool
;
2140 unsigned long flags
;
2142 spin_lock_irqsave(&pool
->lock
, flags
);
2143 pool
->low_water_triggered
= 0;
2144 pool
->no_free_space
= 0;
2145 __requeue_bios(pool
);
2146 spin_unlock_irqrestore(&pool
->lock
, flags
);
2148 do_waker(&pool
->waker
.work
);
2151 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
);
2158 (void) commit_or_fallback(pool
);
2161 static int check_arg_count(unsigned argc
, unsigned args_required
)
2163 if (argc
!= args_required
) {
2164 DMWARN("Message received with %u arguments instead of %u.",
2165 argc
, args_required
);
2172 static int read_dev_id(char *arg
, dm_thin_id
*dev_id
, int warning
)
2174 if (!kstrtoull(arg
, 10, (unsigned long long *)dev_id
) &&
2175 *dev_id
<= MAX_DEV_ID
)
2179 DMWARN("Message received with invalid device id: %s", arg
);
2184 static int process_create_thin_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2189 r
= check_arg_count(argc
, 2);
2193 r
= read_dev_id(argv
[1], &dev_id
, 1);
2197 r
= dm_pool_create_thin(pool
->pmd
, dev_id
);
2199 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2207 static int process_create_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2210 dm_thin_id origin_dev_id
;
2213 r
= check_arg_count(argc
, 3);
2217 r
= read_dev_id(argv
[1], &dev_id
, 1);
2221 r
= read_dev_id(argv
[2], &origin_dev_id
, 1);
2225 r
= dm_pool_create_snap(pool
->pmd
, dev_id
, origin_dev_id
);
2227 DMWARN("Creation of new snapshot %s of device %s failed.",
2235 static int process_delete_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2240 r
= check_arg_count(argc
, 2);
2244 r
= read_dev_id(argv
[1], &dev_id
, 1);
2248 r
= dm_pool_delete_thin_device(pool
->pmd
, dev_id
);
2250 DMWARN("Deletion of thin device %s failed.", argv
[1]);
2255 static int process_set_transaction_id_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2257 dm_thin_id old_id
, new_id
;
2260 r
= check_arg_count(argc
, 3);
2264 if (kstrtoull(argv
[1], 10, (unsigned long long *)&old_id
)) {
2265 DMWARN("set_transaction_id message: Unrecognised id %s.", argv
[1]);
2269 if (kstrtoull(argv
[2], 10, (unsigned long long *)&new_id
)) {
2270 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv
[2]);
2274 r
= dm_pool_set_metadata_transaction_id(pool
->pmd
, old_id
, new_id
);
2276 DMWARN("Failed to change transaction id from %s to %s.",
2284 static int process_reserve_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2288 r
= check_arg_count(argc
, 1);
2292 (void) commit_or_fallback(pool
);
2294 r
= dm_pool_reserve_metadata_snap(pool
->pmd
);
2296 DMWARN("reserve_metadata_snap message failed.");
2301 static int process_release_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2305 r
= check_arg_count(argc
, 1);
2309 r
= dm_pool_release_metadata_snap(pool
->pmd
);
2311 DMWARN("release_metadata_snap message failed.");
2317 * Messages supported:
2318 * create_thin <dev_id>
2319 * create_snap <dev_id> <origin_id>
2321 * trim <dev_id> <new_size_in_sectors>
2322 * set_transaction_id <current_trans_id> <new_trans_id>
2323 * reserve_metadata_snap
2324 * release_metadata_snap
2326 static int pool_message(struct dm_target
*ti
, unsigned argc
, char **argv
)
2329 struct pool_c
*pt
= ti
->private;
2330 struct pool
*pool
= pt
->pool
;
2332 if (!strcasecmp(argv
[0], "create_thin"))
2333 r
= process_create_thin_mesg(argc
, argv
, pool
);
2335 else if (!strcasecmp(argv
[0], "create_snap"))
2336 r
= process_create_snap_mesg(argc
, argv
, pool
);
2338 else if (!strcasecmp(argv
[0], "delete"))
2339 r
= process_delete_mesg(argc
, argv
, pool
);
2341 else if (!strcasecmp(argv
[0], "set_transaction_id"))
2342 r
= process_set_transaction_id_mesg(argc
, argv
, pool
);
2344 else if (!strcasecmp(argv
[0], "reserve_metadata_snap"))
2345 r
= process_reserve_metadata_snap_mesg(argc
, argv
, pool
);
2347 else if (!strcasecmp(argv
[0], "release_metadata_snap"))
2348 r
= process_release_metadata_snap_mesg(argc
, argv
, pool
);
2351 DMWARN("Unrecognised thin pool target message received: %s", argv
[0]);
2354 (void) commit_or_fallback(pool
);
2359 static void emit_flags(struct pool_features
*pf
, char *result
,
2360 unsigned sz
, unsigned maxlen
)
2362 unsigned count
= !pf
->zero_new_blocks
+ !pf
->discard_enabled
+
2363 !pf
->discard_passdown
+ (pf
->mode
== PM_READ_ONLY
);
2364 DMEMIT("%u ", count
);
2366 if (!pf
->zero_new_blocks
)
2367 DMEMIT("skip_block_zeroing ");
2369 if (!pf
->discard_enabled
)
2370 DMEMIT("ignore_discard ");
2372 if (!pf
->discard_passdown
)
2373 DMEMIT("no_discard_passdown ");
2375 if (pf
->mode
== PM_READ_ONLY
)
2376 DMEMIT("read_only ");
2381 * <transaction id> <used metadata sectors>/<total metadata sectors>
2382 * <used data sectors>/<total data sectors> <held metadata root>
2384 static void pool_status(struct dm_target
*ti
, status_type_t type
,
2385 unsigned status_flags
, char *result
, unsigned maxlen
)
2389 uint64_t transaction_id
;
2390 dm_block_t nr_free_blocks_data
;
2391 dm_block_t nr_free_blocks_metadata
;
2392 dm_block_t nr_blocks_data
;
2393 dm_block_t nr_blocks_metadata
;
2394 dm_block_t held_root
;
2395 char buf
[BDEVNAME_SIZE
];
2396 char buf2
[BDEVNAME_SIZE
];
2397 struct pool_c
*pt
= ti
->private;
2398 struct pool
*pool
= pt
->pool
;
2401 case STATUSTYPE_INFO
:
2402 if (get_pool_mode(pool
) == PM_FAIL
) {
2407 /* Commit to ensure statistics aren't out-of-date */
2408 if (!(status_flags
& DM_STATUS_NOFLUSH_FLAG
) && !dm_suspended(ti
))
2409 (void) commit_or_fallback(pool
);
2411 r
= dm_pool_get_metadata_transaction_id(pool
->pmd
, &transaction_id
);
2413 DMERR("dm_pool_get_metadata_transaction_id returned %d", r
);
2417 r
= dm_pool_get_free_metadata_block_count(pool
->pmd
, &nr_free_blocks_metadata
);
2419 DMERR("dm_pool_get_free_metadata_block_count returned %d", r
);
2423 r
= dm_pool_get_metadata_dev_size(pool
->pmd
, &nr_blocks_metadata
);
2425 DMERR("dm_pool_get_metadata_dev_size returned %d", r
);
2429 r
= dm_pool_get_free_block_count(pool
->pmd
, &nr_free_blocks_data
);
2431 DMERR("dm_pool_get_free_block_count returned %d", r
);
2435 r
= dm_pool_get_data_dev_size(pool
->pmd
, &nr_blocks_data
);
2437 DMERR("dm_pool_get_data_dev_size returned %d", r
);
2441 r
= dm_pool_get_metadata_snap(pool
->pmd
, &held_root
);
2443 DMERR("dm_pool_get_metadata_snap returned %d", r
);
2447 DMEMIT("%llu %llu/%llu %llu/%llu ",
2448 (unsigned long long)transaction_id
,
2449 (unsigned long long)(nr_blocks_metadata
- nr_free_blocks_metadata
),
2450 (unsigned long long)nr_blocks_metadata
,
2451 (unsigned long long)(nr_blocks_data
- nr_free_blocks_data
),
2452 (unsigned long long)nr_blocks_data
);
2455 DMEMIT("%llu ", held_root
);
2459 if (pool
->pf
.mode
== PM_READ_ONLY
)
2464 if (!pool
->pf
.discard_enabled
)
2465 DMEMIT("ignore_discard");
2466 else if (pool
->pf
.discard_passdown
)
2467 DMEMIT("discard_passdown");
2469 DMEMIT("no_discard_passdown");
2473 case STATUSTYPE_TABLE
:
2474 DMEMIT("%s %s %lu %llu ",
2475 format_dev_t(buf
, pt
->metadata_dev
->bdev
->bd_dev
),
2476 format_dev_t(buf2
, pt
->data_dev
->bdev
->bd_dev
),
2477 (unsigned long)pool
->sectors_per_block
,
2478 (unsigned long long)pt
->low_water_blocks
);
2479 emit_flags(&pt
->requested_pf
, result
, sz
, maxlen
);
2488 static int pool_iterate_devices(struct dm_target
*ti
,
2489 iterate_devices_callout_fn fn
, void *data
)
2491 struct pool_c
*pt
= ti
->private;
2493 return fn(ti
, pt
->data_dev
, 0, ti
->len
, data
);
2496 static int pool_merge(struct dm_target
*ti
, struct bvec_merge_data
*bvm
,
2497 struct bio_vec
*biovec
, int max_size
)
2499 struct pool_c
*pt
= ti
->private;
2500 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
2502 if (!q
->merge_bvec_fn
)
2505 bvm
->bi_bdev
= pt
->data_dev
->bdev
;
2507 return min(max_size
, q
->merge_bvec_fn(q
, bvm
, biovec
));
2510 static void set_discard_limits(struct pool_c
*pt
, struct queue_limits
*limits
)
2512 struct pool
*pool
= pt
->pool
;
2513 struct queue_limits
*data_limits
;
2515 limits
->max_discard_sectors
= pool
->sectors_per_block
;
2518 * discard_granularity is just a hint, and not enforced.
2520 if (pt
->adjusted_pf
.discard_passdown
) {
2521 data_limits
= &bdev_get_queue(pt
->data_dev
->bdev
)->limits
;
2522 limits
->discard_granularity
= data_limits
->discard_granularity
;
2524 limits
->discard_granularity
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
2527 static void pool_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
2529 struct pool_c
*pt
= ti
->private;
2530 struct pool
*pool
= pt
->pool
;
2532 blk_limits_io_min(limits
, 0);
2533 blk_limits_io_opt(limits
, pool
->sectors_per_block
<< SECTOR_SHIFT
);
2536 * pt->adjusted_pf is a staging area for the actual features to use.
2537 * They get transferred to the live pool in bind_control_target()
2538 * called from pool_preresume().
2540 if (!pt
->adjusted_pf
.discard_enabled
)
2543 disable_passdown_if_not_supported(pt
);
2545 set_discard_limits(pt
, limits
);
2548 static struct target_type pool_target
= {
2549 .name
= "thin-pool",
2550 .features
= DM_TARGET_SINGLETON
| DM_TARGET_ALWAYS_WRITEABLE
|
2551 DM_TARGET_IMMUTABLE
,
2552 .version
= {1, 7, 0},
2553 .module
= THIS_MODULE
,
2557 .postsuspend
= pool_postsuspend
,
2558 .preresume
= pool_preresume
,
2559 .resume
= pool_resume
,
2560 .message
= pool_message
,
2561 .status
= pool_status
,
2562 .merge
= pool_merge
,
2563 .iterate_devices
= pool_iterate_devices
,
2564 .io_hints
= pool_io_hints
,
2567 /*----------------------------------------------------------------
2568 * Thin target methods
2569 *--------------------------------------------------------------*/
2570 static void thin_dtr(struct dm_target
*ti
)
2572 struct thin_c
*tc
= ti
->private;
2574 mutex_lock(&dm_thin_pool_table
.mutex
);
2576 __pool_dec(tc
->pool
);
2577 dm_pool_close_thin_device(tc
->td
);
2578 dm_put_device(ti
, tc
->pool_dev
);
2580 dm_put_device(ti
, tc
->origin_dev
);
2583 mutex_unlock(&dm_thin_pool_table
.mutex
);
2587 * Thin target parameters:
2589 * <pool_dev> <dev_id> [origin_dev]
2591 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2592 * dev_id: the internal device identifier
2593 * origin_dev: a device external to the pool that should act as the origin
2595 * If the pool device has discards disabled, they get disabled for the thin
2598 static int thin_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
2602 struct dm_dev
*pool_dev
, *origin_dev
;
2603 struct mapped_device
*pool_md
;
2605 mutex_lock(&dm_thin_pool_table
.mutex
);
2607 if (argc
!= 2 && argc
!= 3) {
2608 ti
->error
= "Invalid argument count";
2613 tc
= ti
->private = kzalloc(sizeof(*tc
), GFP_KERNEL
);
2615 ti
->error
= "Out of memory";
2621 r
= dm_get_device(ti
, argv
[2], FMODE_READ
, &origin_dev
);
2623 ti
->error
= "Error opening origin device";
2624 goto bad_origin_dev
;
2626 tc
->origin_dev
= origin_dev
;
2629 r
= dm_get_device(ti
, argv
[0], dm_table_get_mode(ti
->table
), &pool_dev
);
2631 ti
->error
= "Error opening pool device";
2634 tc
->pool_dev
= pool_dev
;
2636 if (read_dev_id(argv
[1], (unsigned long long *)&tc
->dev_id
, 0)) {
2637 ti
->error
= "Invalid device id";
2642 pool_md
= dm_get_md(tc
->pool_dev
->bdev
->bd_dev
);
2644 ti
->error
= "Couldn't get pool mapped device";
2649 tc
->pool
= __pool_table_lookup(pool_md
);
2651 ti
->error
= "Couldn't find pool object";
2653 goto bad_pool_lookup
;
2655 __pool_inc(tc
->pool
);
2657 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
2658 ti
->error
= "Couldn't open thin device, Pool is in fail mode";
2662 r
= dm_pool_open_thin_device(tc
->pool
->pmd
, tc
->dev_id
, &tc
->td
);
2664 ti
->error
= "Couldn't open thin internal device";
2668 r
= dm_set_target_max_io_len(ti
, tc
->pool
->sectors_per_block
);
2672 ti
->num_flush_bios
= 1;
2673 ti
->flush_supported
= true;
2674 ti
->per_bio_data_size
= sizeof(struct dm_thin_endio_hook
);
2676 /* In case the pool supports discards, pass them on. */
2677 if (tc
->pool
->pf
.discard_enabled
) {
2678 ti
->discards_supported
= true;
2679 ti
->num_discard_bios
= 1;
2680 ti
->discard_zeroes_data_unsupported
= true;
2681 /* Discard bios must be split on a block boundary */
2682 ti
->split_discard_bios
= true;
2687 mutex_unlock(&dm_thin_pool_table
.mutex
);
2692 __pool_dec(tc
->pool
);
2696 dm_put_device(ti
, tc
->pool_dev
);
2699 dm_put_device(ti
, tc
->origin_dev
);
2703 mutex_unlock(&dm_thin_pool_table
.mutex
);
2708 static int thin_map(struct dm_target
*ti
, struct bio
*bio
)
2710 bio
->bi_sector
= dm_target_offset(ti
, bio
->bi_sector
);
2712 return thin_bio_map(ti
, bio
);
2715 static int thin_endio(struct dm_target
*ti
, struct bio
*bio
, int err
)
2717 unsigned long flags
;
2718 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
2719 struct list_head work
;
2720 struct dm_thin_new_mapping
*m
, *tmp
;
2721 struct pool
*pool
= h
->tc
->pool
;
2723 if (h
->shared_read_entry
) {
2724 INIT_LIST_HEAD(&work
);
2725 dm_deferred_entry_dec(h
->shared_read_entry
, &work
);
2727 spin_lock_irqsave(&pool
->lock
, flags
);
2728 list_for_each_entry_safe(m
, tmp
, &work
, list
) {
2731 __maybe_add_mapping(m
);
2733 spin_unlock_irqrestore(&pool
->lock
, flags
);
2736 if (h
->all_io_entry
) {
2737 INIT_LIST_HEAD(&work
);
2738 dm_deferred_entry_dec(h
->all_io_entry
, &work
);
2739 if (!list_empty(&work
)) {
2740 spin_lock_irqsave(&pool
->lock
, flags
);
2741 list_for_each_entry_safe(m
, tmp
, &work
, list
)
2742 list_add(&m
->list
, &pool
->prepared_discards
);
2743 spin_unlock_irqrestore(&pool
->lock
, flags
);
2751 static void thin_postsuspend(struct dm_target
*ti
)
2753 if (dm_noflush_suspending(ti
))
2754 requeue_io((struct thin_c
*)ti
->private);
2758 * <nr mapped sectors> <highest mapped sector>
2760 static void thin_status(struct dm_target
*ti
, status_type_t type
,
2761 unsigned status_flags
, char *result
, unsigned maxlen
)
2765 dm_block_t mapped
, highest
;
2766 char buf
[BDEVNAME_SIZE
];
2767 struct thin_c
*tc
= ti
->private;
2769 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
2778 case STATUSTYPE_INFO
:
2779 r
= dm_thin_get_mapped_count(tc
->td
, &mapped
);
2781 DMERR("dm_thin_get_mapped_count returned %d", r
);
2785 r
= dm_thin_get_highest_mapped_block(tc
->td
, &highest
);
2787 DMERR("dm_thin_get_highest_mapped_block returned %d", r
);
2791 DMEMIT("%llu ", mapped
* tc
->pool
->sectors_per_block
);
2793 DMEMIT("%llu", ((highest
+ 1) *
2794 tc
->pool
->sectors_per_block
) - 1);
2799 case STATUSTYPE_TABLE
:
2801 format_dev_t(buf
, tc
->pool_dev
->bdev
->bd_dev
),
2802 (unsigned long) tc
->dev_id
);
2804 DMEMIT(" %s", format_dev_t(buf
, tc
->origin_dev
->bdev
->bd_dev
));
2815 static int thin_iterate_devices(struct dm_target
*ti
,
2816 iterate_devices_callout_fn fn
, void *data
)
2819 struct thin_c
*tc
= ti
->private;
2820 struct pool
*pool
= tc
->pool
;
2823 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2824 * we follow a more convoluted path through to the pool's target.
2827 return 0; /* nothing is bound */
2829 blocks
= pool
->ti
->len
;
2830 (void) sector_div(blocks
, pool
->sectors_per_block
);
2832 return fn(ti
, tc
->pool_dev
, 0, pool
->sectors_per_block
* blocks
, data
);
2837 static struct target_type thin_target
= {
2839 .version
= {1, 8, 0},
2840 .module
= THIS_MODULE
,
2844 .end_io
= thin_endio
,
2845 .postsuspend
= thin_postsuspend
,
2846 .status
= thin_status
,
2847 .iterate_devices
= thin_iterate_devices
,
2850 /*----------------------------------------------------------------*/
2852 static int __init
dm_thin_init(void)
2858 r
= dm_register_target(&thin_target
);
2862 r
= dm_register_target(&pool_target
);
2864 goto bad_pool_target
;
2868 _new_mapping_cache
= KMEM_CACHE(dm_thin_new_mapping
, 0);
2869 if (!_new_mapping_cache
)
2870 goto bad_new_mapping_cache
;
2874 bad_new_mapping_cache
:
2875 dm_unregister_target(&pool_target
);
2877 dm_unregister_target(&thin_target
);
2882 static void dm_thin_exit(void)
2884 dm_unregister_target(&thin_target
);
2885 dm_unregister_target(&pool_target
);
2887 kmem_cache_destroy(_new_mapping_cache
);
2890 module_init(dm_thin_init
);
2891 module_exit(dm_thin_exit
);
2893 MODULE_DESCRIPTION(DM_NAME
" thin provisioning target");
2894 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2895 MODULE_LICENSE("GPL");