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_iter
.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_iter
.bi_sector
;
431 bio
->bi_bdev
= tc
->pool_dev
->bdev
;
432 if (block_size_is_power_of_two(pool
))
433 bio
->bi_iter
.bi_sector
=
434 (block
<< pool
->sectors_per_block_shift
) |
435 (bi_sector
& (pool
->sectors_per_block
- 1));
437 bio
->bi_iter
.bi_sector
= (block
* pool
->sectors_per_block
) +
438 sector_div(bi_sector
, pool
->sectors_per_block
);
441 static void remap_to_origin(struct thin_c
*tc
, struct bio
*bio
)
443 bio
->bi_bdev
= tc
->origin_dev
->bdev
;
446 static int bio_triggers_commit(struct thin_c
*tc
, struct bio
*bio
)
448 return (bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
)) &&
449 dm_thin_changed_this_transaction(tc
->td
);
452 static void inc_all_io_entry(struct pool
*pool
, struct bio
*bio
)
454 struct dm_thin_endio_hook
*h
;
456 if (bio
->bi_rw
& REQ_DISCARD
)
459 h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
460 h
->all_io_entry
= dm_deferred_entry_inc(pool
->all_io_ds
);
463 static void issue(struct thin_c
*tc
, struct bio
*bio
)
465 struct pool
*pool
= tc
->pool
;
468 if (!bio_triggers_commit(tc
, bio
)) {
469 generic_make_request(bio
);
474 * Complete bio with an error if earlier I/O caused changes to
475 * the metadata that can't be committed e.g, due to I/O errors
476 * on the metadata device.
478 if (dm_thin_aborted_changes(tc
->td
)) {
484 * Batch together any bios that trigger commits and then issue a
485 * single commit for them in process_deferred_bios().
487 spin_lock_irqsave(&pool
->lock
, flags
);
488 bio_list_add(&pool
->deferred_flush_bios
, bio
);
489 spin_unlock_irqrestore(&pool
->lock
, flags
);
492 static void remap_to_origin_and_issue(struct thin_c
*tc
, struct bio
*bio
)
494 remap_to_origin(tc
, bio
);
498 static void remap_and_issue(struct thin_c
*tc
, struct bio
*bio
,
501 remap(tc
, bio
, block
);
505 /*----------------------------------------------------------------*/
508 * Bio endio functions.
510 struct dm_thin_new_mapping
{
511 struct list_head list
;
515 unsigned pass_discard
:1;
518 dm_block_t virt_block
;
519 dm_block_t data_block
;
520 struct dm_bio_prison_cell
*cell
, *cell2
;
524 * If the bio covers the whole area of a block then we can avoid
525 * zeroing or copying. Instead this bio is hooked. The bio will
526 * still be in the cell, so care has to be taken to avoid issuing
530 bio_end_io_t
*saved_bi_end_io
;
533 static void __maybe_add_mapping(struct dm_thin_new_mapping
*m
)
535 struct pool
*pool
= m
->tc
->pool
;
537 if (m
->quiesced
&& m
->prepared
) {
538 list_add(&m
->list
, &pool
->prepared_mappings
);
543 static void copy_complete(int read_err
, unsigned long write_err
, void *context
)
546 struct dm_thin_new_mapping
*m
= context
;
547 struct pool
*pool
= m
->tc
->pool
;
549 m
->err
= read_err
|| write_err
? -EIO
: 0;
551 spin_lock_irqsave(&pool
->lock
, flags
);
553 __maybe_add_mapping(m
);
554 spin_unlock_irqrestore(&pool
->lock
, flags
);
557 static void overwrite_endio(struct bio
*bio
, int err
)
560 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
561 struct dm_thin_new_mapping
*m
= h
->overwrite_mapping
;
562 struct pool
*pool
= m
->tc
->pool
;
566 spin_lock_irqsave(&pool
->lock
, flags
);
568 __maybe_add_mapping(m
);
569 spin_unlock_irqrestore(&pool
->lock
, flags
);
572 /*----------------------------------------------------------------*/
579 * Prepared mapping jobs.
583 * This sends the bios in the cell back to the deferred_bios list.
585 static void cell_defer(struct thin_c
*tc
, struct dm_bio_prison_cell
*cell
)
587 struct pool
*pool
= tc
->pool
;
590 spin_lock_irqsave(&pool
->lock
, flags
);
591 cell_release(pool
, cell
, &pool
->deferred_bios
);
592 spin_unlock_irqrestore(&tc
->pool
->lock
, flags
);
598 * Same as cell_defer above, except it omits the original holder of the cell.
600 static void cell_defer_no_holder(struct thin_c
*tc
, struct dm_bio_prison_cell
*cell
)
602 struct pool
*pool
= tc
->pool
;
605 spin_lock_irqsave(&pool
->lock
, flags
);
606 cell_release_no_holder(pool
, cell
, &pool
->deferred_bios
);
607 spin_unlock_irqrestore(&pool
->lock
, flags
);
612 static void process_prepared_mapping_fail(struct dm_thin_new_mapping
*m
)
615 m
->bio
->bi_end_io
= m
->saved_bi_end_io
;
616 cell_error(m
->tc
->pool
, m
->cell
);
618 mempool_free(m
, m
->tc
->pool
->mapping_pool
);
621 static void process_prepared_mapping(struct dm_thin_new_mapping
*m
)
623 struct thin_c
*tc
= m
->tc
;
624 struct pool
*pool
= tc
->pool
;
630 bio
->bi_end_io
= m
->saved_bi_end_io
;
633 cell_error(pool
, m
->cell
);
638 * Commit the prepared block into the mapping btree.
639 * Any I/O for this block arriving after this point will get
640 * remapped to it directly.
642 r
= dm_thin_insert_block(tc
->td
, m
->virt_block
, m
->data_block
);
644 DMERR_LIMIT("dm_thin_insert_block() failed");
645 cell_error(pool
, m
->cell
);
650 * Release any bios held while the block was being provisioned.
651 * If we are processing a write bio that completely covers the block,
652 * we already processed it so can ignore it now when processing
653 * the bios in the cell.
656 cell_defer_no_holder(tc
, m
->cell
);
659 cell_defer(tc
, m
->cell
);
663 mempool_free(m
, pool
->mapping_pool
);
666 static void process_prepared_discard_fail(struct dm_thin_new_mapping
*m
)
668 struct thin_c
*tc
= m
->tc
;
670 bio_io_error(m
->bio
);
671 cell_defer_no_holder(tc
, m
->cell
);
672 cell_defer_no_holder(tc
, m
->cell2
);
673 mempool_free(m
, tc
->pool
->mapping_pool
);
676 static void process_prepared_discard_passdown(struct dm_thin_new_mapping
*m
)
678 struct thin_c
*tc
= m
->tc
;
680 inc_all_io_entry(tc
->pool
, m
->bio
);
681 cell_defer_no_holder(tc
, m
->cell
);
682 cell_defer_no_holder(tc
, m
->cell2
);
685 remap_and_issue(tc
, m
->bio
, m
->data_block
);
687 bio_endio(m
->bio
, 0);
689 mempool_free(m
, tc
->pool
->mapping_pool
);
692 static void process_prepared_discard(struct dm_thin_new_mapping
*m
)
695 struct thin_c
*tc
= m
->tc
;
697 r
= dm_thin_remove_block(tc
->td
, m
->virt_block
);
699 DMERR_LIMIT("dm_thin_remove_block() failed");
701 process_prepared_discard_passdown(m
);
704 static void process_prepared(struct pool
*pool
, struct list_head
*head
,
705 process_mapping_fn
*fn
)
708 struct list_head maps
;
709 struct dm_thin_new_mapping
*m
, *tmp
;
711 INIT_LIST_HEAD(&maps
);
712 spin_lock_irqsave(&pool
->lock
, flags
);
713 list_splice_init(head
, &maps
);
714 spin_unlock_irqrestore(&pool
->lock
, flags
);
716 list_for_each_entry_safe(m
, tmp
, &maps
, list
)
723 static int io_overlaps_block(struct pool
*pool
, struct bio
*bio
)
725 return bio
->bi_iter
.bi_size
==
726 (pool
->sectors_per_block
<< SECTOR_SHIFT
);
729 static int io_overwrites_block(struct pool
*pool
, struct bio
*bio
)
731 return (bio_data_dir(bio
) == WRITE
) &&
732 io_overlaps_block(pool
, bio
);
735 static void save_and_set_endio(struct bio
*bio
, bio_end_io_t
**save
,
738 *save
= bio
->bi_end_io
;
742 static int ensure_next_mapping(struct pool
*pool
)
744 if (pool
->next_mapping
)
747 pool
->next_mapping
= mempool_alloc(pool
->mapping_pool
, GFP_ATOMIC
);
749 return pool
->next_mapping
? 0 : -ENOMEM
;
752 static struct dm_thin_new_mapping
*get_next_mapping(struct pool
*pool
)
754 struct dm_thin_new_mapping
*r
= pool
->next_mapping
;
756 BUG_ON(!pool
->next_mapping
);
758 pool
->next_mapping
= NULL
;
763 static void schedule_copy(struct thin_c
*tc
, dm_block_t virt_block
,
764 struct dm_dev
*origin
, dm_block_t data_origin
,
765 dm_block_t data_dest
,
766 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
769 struct pool
*pool
= tc
->pool
;
770 struct dm_thin_new_mapping
*m
= get_next_mapping(pool
);
772 INIT_LIST_HEAD(&m
->list
);
776 m
->virt_block
= virt_block
;
777 m
->data_block
= data_dest
;
782 if (!dm_deferred_set_add_work(pool
->shared_read_ds
, &m
->list
))
786 * IO to pool_dev remaps to the pool target's data_dev.
788 * If the whole block of data is being overwritten, we can issue the
789 * bio immediately. Otherwise we use kcopyd to clone the data first.
791 if (io_overwrites_block(pool
, bio
)) {
792 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
794 h
->overwrite_mapping
= m
;
796 save_and_set_endio(bio
, &m
->saved_bi_end_io
, overwrite_endio
);
797 inc_all_io_entry(pool
, bio
);
798 remap_and_issue(tc
, bio
, data_dest
);
800 struct dm_io_region from
, to
;
802 from
.bdev
= origin
->bdev
;
803 from
.sector
= data_origin
* pool
->sectors_per_block
;
804 from
.count
= pool
->sectors_per_block
;
806 to
.bdev
= tc
->pool_dev
->bdev
;
807 to
.sector
= data_dest
* pool
->sectors_per_block
;
808 to
.count
= pool
->sectors_per_block
;
810 r
= dm_kcopyd_copy(pool
->copier
, &from
, 1, &to
,
811 0, copy_complete
, m
);
813 mempool_free(m
, pool
->mapping_pool
);
814 DMERR_LIMIT("dm_kcopyd_copy() failed");
815 cell_error(pool
, cell
);
820 static void schedule_internal_copy(struct thin_c
*tc
, dm_block_t virt_block
,
821 dm_block_t data_origin
, dm_block_t data_dest
,
822 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
824 schedule_copy(tc
, virt_block
, tc
->pool_dev
,
825 data_origin
, data_dest
, cell
, bio
);
828 static void schedule_external_copy(struct thin_c
*tc
, dm_block_t virt_block
,
829 dm_block_t data_dest
,
830 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
832 schedule_copy(tc
, virt_block
, tc
->origin_dev
,
833 virt_block
, data_dest
, cell
, bio
);
836 static void schedule_zero(struct thin_c
*tc
, dm_block_t virt_block
,
837 dm_block_t data_block
, struct dm_bio_prison_cell
*cell
,
840 struct pool
*pool
= tc
->pool
;
841 struct dm_thin_new_mapping
*m
= get_next_mapping(pool
);
843 INIT_LIST_HEAD(&m
->list
);
847 m
->virt_block
= virt_block
;
848 m
->data_block
= data_block
;
854 * If the whole block of data is being overwritten or we are not
855 * zeroing pre-existing data, we can issue the bio immediately.
856 * Otherwise we use kcopyd to zero the data first.
858 if (!pool
->pf
.zero_new_blocks
)
859 process_prepared_mapping(m
);
861 else if (io_overwrites_block(pool
, bio
)) {
862 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
864 h
->overwrite_mapping
= m
;
866 save_and_set_endio(bio
, &m
->saved_bi_end_io
, overwrite_endio
);
867 inc_all_io_entry(pool
, bio
);
868 remap_and_issue(tc
, bio
, data_block
);
871 struct dm_io_region to
;
873 to
.bdev
= tc
->pool_dev
->bdev
;
874 to
.sector
= data_block
* pool
->sectors_per_block
;
875 to
.count
= pool
->sectors_per_block
;
877 r
= dm_kcopyd_zero(pool
->copier
, 1, &to
, 0, copy_complete
, m
);
879 mempool_free(m
, pool
->mapping_pool
);
880 DMERR_LIMIT("dm_kcopyd_zero() failed");
881 cell_error(pool
, cell
);
886 static int commit(struct pool
*pool
)
890 r
= dm_pool_commit_metadata(pool
->pmd
);
892 DMERR_LIMIT("%s: commit failed: error = %d",
893 dm_device_name(pool
->pool_md
), r
);
899 * A non-zero return indicates read_only or fail_io mode.
900 * Many callers don't care about the return value.
902 static int commit_or_fallback(struct pool
*pool
)
906 if (get_pool_mode(pool
) != PM_WRITE
)
911 set_pool_mode(pool
, PM_READ_ONLY
);
916 static int alloc_data_block(struct thin_c
*tc
, dm_block_t
*result
)
919 dm_block_t free_blocks
;
921 struct pool
*pool
= tc
->pool
;
924 * Once no_free_space is set we must not allow allocation to succeed.
925 * Otherwise it is difficult to explain, debug, test and support.
927 if (pool
->no_free_space
)
930 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
934 if (free_blocks
<= pool
->low_water_blocks
&& !pool
->low_water_triggered
) {
935 DMWARN("%s: reached low water mark for data device: sending event.",
936 dm_device_name(pool
->pool_md
));
937 spin_lock_irqsave(&pool
->lock
, flags
);
938 pool
->low_water_triggered
= 1;
939 spin_unlock_irqrestore(&pool
->lock
, flags
);
940 dm_table_event(pool
->ti
->table
);
945 * Try to commit to see if that will free up some
948 (void) commit_or_fallback(pool
);
950 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
955 * If we still have no space we set a flag to avoid
956 * doing all this checking and return -ENOSPC. This
957 * flag serves as a latch that disallows allocations from
958 * this pool until the admin takes action (e.g. resize or
962 DMWARN("%s: no free space available.",
963 dm_device_name(pool
->pool_md
));
964 spin_lock_irqsave(&pool
->lock
, flags
);
965 pool
->no_free_space
= 1;
966 spin_unlock_irqrestore(&pool
->lock
, flags
);
971 r
= dm_pool_alloc_data_block(pool
->pmd
, result
);
979 * If we have run out of space, queue bios until the device is
980 * resumed, presumably after having been reloaded with more space.
982 static void retry_on_resume(struct bio
*bio
)
984 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
985 struct thin_c
*tc
= h
->tc
;
986 struct pool
*pool
= tc
->pool
;
989 spin_lock_irqsave(&pool
->lock
, flags
);
990 bio_list_add(&pool
->retry_on_resume_list
, bio
);
991 spin_unlock_irqrestore(&pool
->lock
, flags
);
994 static void no_space(struct pool
*pool
, struct dm_bio_prison_cell
*cell
)
997 struct bio_list bios
;
999 bio_list_init(&bios
);
1000 cell_release(pool
, cell
, &bios
);
1002 while ((bio
= bio_list_pop(&bios
)))
1003 retry_on_resume(bio
);
1006 static void process_discard(struct thin_c
*tc
, struct bio
*bio
)
1009 unsigned long flags
;
1010 struct pool
*pool
= tc
->pool
;
1011 struct dm_bio_prison_cell
*cell
, *cell2
;
1012 struct dm_cell_key key
, key2
;
1013 dm_block_t block
= get_bio_block(tc
, bio
);
1014 struct dm_thin_lookup_result lookup_result
;
1015 struct dm_thin_new_mapping
*m
;
1017 build_virtual_key(tc
->td
, block
, &key
);
1018 if (bio_detain(tc
->pool
, &key
, bio
, &cell
))
1021 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1025 * Check nobody is fiddling with this pool block. This can
1026 * happen if someone's in the process of breaking sharing
1029 build_data_key(tc
->td
, lookup_result
.block
, &key2
);
1030 if (bio_detain(tc
->pool
, &key2
, bio
, &cell2
)) {
1031 cell_defer_no_holder(tc
, cell
);
1035 if (io_overlaps_block(pool
, bio
)) {
1037 * IO may still be going to the destination block. We must
1038 * quiesce before we can do the removal.
1040 m
= get_next_mapping(pool
);
1042 m
->pass_discard
= (!lookup_result
.shared
) && pool
->pf
.discard_passdown
;
1043 m
->virt_block
= block
;
1044 m
->data_block
= lookup_result
.block
;
1050 if (!dm_deferred_set_add_work(pool
->all_io_ds
, &m
->list
)) {
1051 spin_lock_irqsave(&pool
->lock
, flags
);
1052 list_add(&m
->list
, &pool
->prepared_discards
);
1053 spin_unlock_irqrestore(&pool
->lock
, flags
);
1057 inc_all_io_entry(pool
, bio
);
1058 cell_defer_no_holder(tc
, cell
);
1059 cell_defer_no_holder(tc
, cell2
);
1062 * The DM core makes sure that the discard doesn't span
1063 * a block boundary. So we submit the discard of a
1064 * partial block appropriately.
1066 if ((!lookup_result
.shared
) && pool
->pf
.discard_passdown
)
1067 remap_and_issue(tc
, bio
, lookup_result
.block
);
1075 * It isn't provisioned, just forget it.
1077 cell_defer_no_holder(tc
, cell
);
1082 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1084 cell_defer_no_holder(tc
, cell
);
1090 static void break_sharing(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1091 struct dm_cell_key
*key
,
1092 struct dm_thin_lookup_result
*lookup_result
,
1093 struct dm_bio_prison_cell
*cell
)
1096 dm_block_t data_block
;
1097 struct pool
*pool
= tc
->pool
;
1099 r
= alloc_data_block(tc
, &data_block
);
1102 schedule_internal_copy(tc
, block
, lookup_result
->block
,
1103 data_block
, cell
, bio
);
1107 no_space(pool
, cell
);
1111 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1113 set_pool_mode(pool
, PM_READ_ONLY
);
1114 cell_error(pool
, cell
);
1119 static void process_shared_bio(struct thin_c
*tc
, struct bio
*bio
,
1121 struct dm_thin_lookup_result
*lookup_result
)
1123 struct dm_bio_prison_cell
*cell
;
1124 struct pool
*pool
= tc
->pool
;
1125 struct dm_cell_key key
;
1128 * If cell is already occupied, then sharing is already in the process
1129 * of being broken so we have nothing further to do here.
1131 build_data_key(tc
->td
, lookup_result
->block
, &key
);
1132 if (bio_detain(pool
, &key
, bio
, &cell
))
1135 if (bio_data_dir(bio
) == WRITE
&& bio
->bi_iter
.bi_size
)
1136 break_sharing(tc
, bio
, block
, &key
, lookup_result
, cell
);
1138 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1140 h
->shared_read_entry
= dm_deferred_entry_inc(pool
->shared_read_ds
);
1141 inc_all_io_entry(pool
, bio
);
1142 cell_defer_no_holder(tc
, cell
);
1144 remap_and_issue(tc
, bio
, lookup_result
->block
);
1148 static void provision_block(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1149 struct dm_bio_prison_cell
*cell
)
1152 dm_block_t data_block
;
1153 struct pool
*pool
= tc
->pool
;
1156 * Remap empty bios (flushes) immediately, without provisioning.
1158 if (!bio
->bi_iter
.bi_size
) {
1159 inc_all_io_entry(pool
, bio
);
1160 cell_defer_no_holder(tc
, cell
);
1162 remap_and_issue(tc
, bio
, 0);
1167 * Fill read bios with zeroes and complete them immediately.
1169 if (bio_data_dir(bio
) == READ
) {
1171 cell_defer_no_holder(tc
, cell
);
1176 r
= alloc_data_block(tc
, &data_block
);
1180 schedule_external_copy(tc
, block
, data_block
, cell
, bio
);
1182 schedule_zero(tc
, block
, data_block
, cell
, bio
);
1186 no_space(pool
, cell
);
1190 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1192 set_pool_mode(pool
, PM_READ_ONLY
);
1193 cell_error(pool
, cell
);
1198 static void process_bio(struct thin_c
*tc
, struct bio
*bio
)
1201 struct pool
*pool
= tc
->pool
;
1202 dm_block_t block
= get_bio_block(tc
, bio
);
1203 struct dm_bio_prison_cell
*cell
;
1204 struct dm_cell_key key
;
1205 struct dm_thin_lookup_result lookup_result
;
1208 * If cell is already occupied, then the block is already
1209 * being provisioned so we have nothing further to do here.
1211 build_virtual_key(tc
->td
, block
, &key
);
1212 if (bio_detain(pool
, &key
, bio
, &cell
))
1215 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1218 if (lookup_result
.shared
) {
1219 process_shared_bio(tc
, bio
, block
, &lookup_result
);
1220 cell_defer_no_holder(tc
, cell
); /* FIXME: pass this cell into process_shared? */
1222 inc_all_io_entry(pool
, bio
);
1223 cell_defer_no_holder(tc
, cell
);
1225 remap_and_issue(tc
, bio
, lookup_result
.block
);
1230 if (bio_data_dir(bio
) == READ
&& tc
->origin_dev
) {
1231 inc_all_io_entry(pool
, bio
);
1232 cell_defer_no_holder(tc
, cell
);
1234 remap_to_origin_and_issue(tc
, bio
);
1236 provision_block(tc
, bio
, block
, cell
);
1240 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1242 cell_defer_no_holder(tc
, cell
);
1248 static void process_bio_read_only(struct thin_c
*tc
, struct bio
*bio
)
1251 int rw
= bio_data_dir(bio
);
1252 dm_block_t block
= get_bio_block(tc
, bio
);
1253 struct dm_thin_lookup_result lookup_result
;
1255 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1258 if (lookup_result
.shared
&& (rw
== WRITE
) && bio
->bi_iter
.bi_size
)
1261 inc_all_io_entry(tc
->pool
, bio
);
1262 remap_and_issue(tc
, bio
, lookup_result
.block
);
1272 if (tc
->origin_dev
) {
1273 inc_all_io_entry(tc
->pool
, bio
);
1274 remap_to_origin_and_issue(tc
, bio
);
1283 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1290 static void process_bio_fail(struct thin_c
*tc
, struct bio
*bio
)
1296 * FIXME: should we also commit due to size of transaction, measured in
1299 static int need_commit_due_to_time(struct pool
*pool
)
1301 return jiffies
< pool
->last_commit_jiffies
||
1302 jiffies
> pool
->last_commit_jiffies
+ COMMIT_PERIOD
;
1305 static void process_deferred_bios(struct pool
*pool
)
1307 unsigned long flags
;
1309 struct bio_list bios
;
1311 bio_list_init(&bios
);
1313 spin_lock_irqsave(&pool
->lock
, flags
);
1314 bio_list_merge(&bios
, &pool
->deferred_bios
);
1315 bio_list_init(&pool
->deferred_bios
);
1316 spin_unlock_irqrestore(&pool
->lock
, flags
);
1318 while ((bio
= bio_list_pop(&bios
))) {
1319 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1320 struct thin_c
*tc
= h
->tc
;
1323 * If we've got no free new_mapping structs, and processing
1324 * this bio might require one, we pause until there are some
1325 * prepared mappings to process.
1327 if (ensure_next_mapping(pool
)) {
1328 spin_lock_irqsave(&pool
->lock
, flags
);
1329 bio_list_merge(&pool
->deferred_bios
, &bios
);
1330 spin_unlock_irqrestore(&pool
->lock
, flags
);
1335 if (bio
->bi_rw
& REQ_DISCARD
)
1336 pool
->process_discard(tc
, bio
);
1338 pool
->process_bio(tc
, bio
);
1342 * If there are any deferred flush bios, we must commit
1343 * the metadata before issuing them.
1345 bio_list_init(&bios
);
1346 spin_lock_irqsave(&pool
->lock
, flags
);
1347 bio_list_merge(&bios
, &pool
->deferred_flush_bios
);
1348 bio_list_init(&pool
->deferred_flush_bios
);
1349 spin_unlock_irqrestore(&pool
->lock
, flags
);
1351 if (bio_list_empty(&bios
) && !need_commit_due_to_time(pool
))
1354 if (commit_or_fallback(pool
)) {
1355 while ((bio
= bio_list_pop(&bios
)))
1359 pool
->last_commit_jiffies
= jiffies
;
1361 while ((bio
= bio_list_pop(&bios
)))
1362 generic_make_request(bio
);
1365 static void do_worker(struct work_struct
*ws
)
1367 struct pool
*pool
= container_of(ws
, struct pool
, worker
);
1369 process_prepared(pool
, &pool
->prepared_mappings
, &pool
->process_prepared_mapping
);
1370 process_prepared(pool
, &pool
->prepared_discards
, &pool
->process_prepared_discard
);
1371 process_deferred_bios(pool
);
1375 * We want to commit periodically so that not too much
1376 * unwritten data builds up.
1378 static void do_waker(struct work_struct
*ws
)
1380 struct pool
*pool
= container_of(to_delayed_work(ws
), struct pool
, waker
);
1382 queue_delayed_work(pool
->wq
, &pool
->waker
, COMMIT_PERIOD
);
1385 /*----------------------------------------------------------------*/
1387 static enum pool_mode
get_pool_mode(struct pool
*pool
)
1389 return pool
->pf
.mode
;
1392 static void set_pool_mode(struct pool
*pool
, enum pool_mode mode
)
1396 pool
->pf
.mode
= mode
;
1400 DMERR("%s: switching pool to failure mode",
1401 dm_device_name(pool
->pool_md
));
1402 pool
->process_bio
= process_bio_fail
;
1403 pool
->process_discard
= process_bio_fail
;
1404 pool
->process_prepared_mapping
= process_prepared_mapping_fail
;
1405 pool
->process_prepared_discard
= process_prepared_discard_fail
;
1409 DMERR("%s: switching pool to read-only mode",
1410 dm_device_name(pool
->pool_md
));
1411 r
= dm_pool_abort_metadata(pool
->pmd
);
1413 DMERR("%s: aborting transaction failed",
1414 dm_device_name(pool
->pool_md
));
1415 set_pool_mode(pool
, PM_FAIL
);
1417 dm_pool_metadata_read_only(pool
->pmd
);
1418 pool
->process_bio
= process_bio_read_only
;
1419 pool
->process_discard
= process_discard
;
1420 pool
->process_prepared_mapping
= process_prepared_mapping_fail
;
1421 pool
->process_prepared_discard
= process_prepared_discard_passdown
;
1426 pool
->process_bio
= process_bio
;
1427 pool
->process_discard
= process_discard
;
1428 pool
->process_prepared_mapping
= process_prepared_mapping
;
1429 pool
->process_prepared_discard
= process_prepared_discard
;
1434 /*----------------------------------------------------------------*/
1437 * Mapping functions.
1441 * Called only while mapping a thin bio to hand it over to the workqueue.
1443 static void thin_defer_bio(struct thin_c
*tc
, struct bio
*bio
)
1445 unsigned long flags
;
1446 struct pool
*pool
= tc
->pool
;
1448 spin_lock_irqsave(&pool
->lock
, flags
);
1449 bio_list_add(&pool
->deferred_bios
, bio
);
1450 spin_unlock_irqrestore(&pool
->lock
, flags
);
1455 static void thin_hook_bio(struct thin_c
*tc
, struct bio
*bio
)
1457 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1460 h
->shared_read_entry
= NULL
;
1461 h
->all_io_entry
= NULL
;
1462 h
->overwrite_mapping
= NULL
;
1466 * Non-blocking function called from the thin target's map function.
1468 static int thin_bio_map(struct dm_target
*ti
, struct bio
*bio
)
1471 struct thin_c
*tc
= ti
->private;
1472 dm_block_t block
= get_bio_block(tc
, bio
);
1473 struct dm_thin_device
*td
= tc
->td
;
1474 struct dm_thin_lookup_result result
;
1475 struct dm_bio_prison_cell cell1
, cell2
;
1476 struct dm_bio_prison_cell
*cell_result
;
1477 struct dm_cell_key key
;
1479 thin_hook_bio(tc
, bio
);
1481 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
1483 return DM_MAPIO_SUBMITTED
;
1486 if (bio
->bi_rw
& (REQ_DISCARD
| REQ_FLUSH
| REQ_FUA
)) {
1487 thin_defer_bio(tc
, bio
);
1488 return DM_MAPIO_SUBMITTED
;
1491 r
= dm_thin_find_block(td
, block
, 0, &result
);
1494 * Note that we defer readahead too.
1498 if (unlikely(result
.shared
)) {
1500 * We have a race condition here between the
1501 * result.shared value returned by the lookup and
1502 * snapshot creation, which may cause new
1505 * To avoid this always quiesce the origin before
1506 * taking the snap. You want to do this anyway to
1507 * ensure a consistent application view
1510 * More distant ancestors are irrelevant. The
1511 * shared flag will be set in their case.
1513 thin_defer_bio(tc
, bio
);
1514 return DM_MAPIO_SUBMITTED
;
1517 build_virtual_key(tc
->td
, block
, &key
);
1518 if (dm_bio_detain(tc
->pool
->prison
, &key
, bio
, &cell1
, &cell_result
))
1519 return DM_MAPIO_SUBMITTED
;
1521 build_data_key(tc
->td
, result
.block
, &key
);
1522 if (dm_bio_detain(tc
->pool
->prison
, &key
, bio
, &cell2
, &cell_result
)) {
1523 cell_defer_no_holder_no_free(tc
, &cell1
);
1524 return DM_MAPIO_SUBMITTED
;
1527 inc_all_io_entry(tc
->pool
, bio
);
1528 cell_defer_no_holder_no_free(tc
, &cell2
);
1529 cell_defer_no_holder_no_free(tc
, &cell1
);
1531 remap(tc
, bio
, result
.block
);
1532 return DM_MAPIO_REMAPPED
;
1535 if (get_pool_mode(tc
->pool
) == PM_READ_ONLY
) {
1537 * This block isn't provisioned, and we have no way
1538 * of doing so. Just error it.
1541 return DM_MAPIO_SUBMITTED
;
1547 * In future, the failed dm_thin_find_block above could
1548 * provide the hint to load the metadata into cache.
1550 thin_defer_bio(tc
, bio
);
1551 return DM_MAPIO_SUBMITTED
;
1555 * Must always call bio_io_error on failure.
1556 * dm_thin_find_block can fail with -EINVAL if the
1557 * pool is switched to fail-io mode.
1560 return DM_MAPIO_SUBMITTED
;
1564 static int pool_is_congested(struct dm_target_callbacks
*cb
, int bdi_bits
)
1567 unsigned long flags
;
1568 struct pool_c
*pt
= container_of(cb
, struct pool_c
, callbacks
);
1570 spin_lock_irqsave(&pt
->pool
->lock
, flags
);
1571 r
= !bio_list_empty(&pt
->pool
->retry_on_resume_list
);
1572 spin_unlock_irqrestore(&pt
->pool
->lock
, flags
);
1575 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1576 r
= bdi_congested(&q
->backing_dev_info
, bdi_bits
);
1582 static void __requeue_bios(struct pool
*pool
)
1584 bio_list_merge(&pool
->deferred_bios
, &pool
->retry_on_resume_list
);
1585 bio_list_init(&pool
->retry_on_resume_list
);
1588 /*----------------------------------------------------------------
1589 * Binding of control targets to a pool object
1590 *--------------------------------------------------------------*/
1591 static bool data_dev_supports_discard(struct pool_c
*pt
)
1593 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1595 return q
&& blk_queue_discard(q
);
1598 static bool is_factor(sector_t block_size
, uint32_t n
)
1600 return !sector_div(block_size
, n
);
1604 * If discard_passdown was enabled verify that the data device
1605 * supports discards. Disable discard_passdown if not.
1607 static void disable_passdown_if_not_supported(struct pool_c
*pt
)
1609 struct pool
*pool
= pt
->pool
;
1610 struct block_device
*data_bdev
= pt
->data_dev
->bdev
;
1611 struct queue_limits
*data_limits
= &bdev_get_queue(data_bdev
)->limits
;
1612 sector_t block_size
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
1613 const char *reason
= NULL
;
1614 char buf
[BDEVNAME_SIZE
];
1616 if (!pt
->adjusted_pf
.discard_passdown
)
1619 if (!data_dev_supports_discard(pt
))
1620 reason
= "discard unsupported";
1622 else if (data_limits
->max_discard_sectors
< pool
->sectors_per_block
)
1623 reason
= "max discard sectors smaller than a block";
1625 else if (data_limits
->discard_granularity
> block_size
)
1626 reason
= "discard granularity larger than a block";
1628 else if (!is_factor(block_size
, data_limits
->discard_granularity
))
1629 reason
= "discard granularity not a factor of block size";
1632 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev
, buf
), reason
);
1633 pt
->adjusted_pf
.discard_passdown
= false;
1637 static int bind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1639 struct pool_c
*pt
= ti
->private;
1642 * We want to make sure that degraded pools are never upgraded.
1644 enum pool_mode old_mode
= pool
->pf
.mode
;
1645 enum pool_mode new_mode
= pt
->adjusted_pf
.mode
;
1647 if (old_mode
> new_mode
)
1648 new_mode
= old_mode
;
1651 pool
->low_water_blocks
= pt
->low_water_blocks
;
1652 pool
->pf
= pt
->adjusted_pf
;
1654 set_pool_mode(pool
, new_mode
);
1659 static void unbind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1665 /*----------------------------------------------------------------
1667 *--------------------------------------------------------------*/
1668 /* Initialize pool features. */
1669 static void pool_features_init(struct pool_features
*pf
)
1671 pf
->mode
= PM_WRITE
;
1672 pf
->zero_new_blocks
= true;
1673 pf
->discard_enabled
= true;
1674 pf
->discard_passdown
= true;
1677 static void __pool_destroy(struct pool
*pool
)
1679 __pool_table_remove(pool
);
1681 if (dm_pool_metadata_close(pool
->pmd
) < 0)
1682 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1684 dm_bio_prison_destroy(pool
->prison
);
1685 dm_kcopyd_client_destroy(pool
->copier
);
1688 destroy_workqueue(pool
->wq
);
1690 if (pool
->next_mapping
)
1691 mempool_free(pool
->next_mapping
, pool
->mapping_pool
);
1692 mempool_destroy(pool
->mapping_pool
);
1693 dm_deferred_set_destroy(pool
->shared_read_ds
);
1694 dm_deferred_set_destroy(pool
->all_io_ds
);
1698 static struct kmem_cache
*_new_mapping_cache
;
1700 static struct pool
*pool_create(struct mapped_device
*pool_md
,
1701 struct block_device
*metadata_dev
,
1702 unsigned long block_size
,
1703 int read_only
, char **error
)
1708 struct dm_pool_metadata
*pmd
;
1709 bool format_device
= read_only
? false : true;
1711 pmd
= dm_pool_metadata_open(metadata_dev
, block_size
, format_device
);
1713 *error
= "Error creating metadata object";
1714 return (struct pool
*)pmd
;
1717 pool
= kmalloc(sizeof(*pool
), GFP_KERNEL
);
1719 *error
= "Error allocating memory for pool";
1720 err_p
= ERR_PTR(-ENOMEM
);
1725 pool
->sectors_per_block
= block_size
;
1726 if (block_size
& (block_size
- 1))
1727 pool
->sectors_per_block_shift
= -1;
1729 pool
->sectors_per_block_shift
= __ffs(block_size
);
1730 pool
->low_water_blocks
= 0;
1731 pool_features_init(&pool
->pf
);
1732 pool
->prison
= dm_bio_prison_create(PRISON_CELLS
);
1733 if (!pool
->prison
) {
1734 *error
= "Error creating pool's bio prison";
1735 err_p
= ERR_PTR(-ENOMEM
);
1739 pool
->copier
= dm_kcopyd_client_create(&dm_kcopyd_throttle
);
1740 if (IS_ERR(pool
->copier
)) {
1741 r
= PTR_ERR(pool
->copier
);
1742 *error
= "Error creating pool's kcopyd client";
1744 goto bad_kcopyd_client
;
1748 * Create singlethreaded workqueue that will service all devices
1749 * that use this metadata.
1751 pool
->wq
= alloc_ordered_workqueue("dm-" DM_MSG_PREFIX
, WQ_MEM_RECLAIM
);
1753 *error
= "Error creating pool's workqueue";
1754 err_p
= ERR_PTR(-ENOMEM
);
1758 INIT_WORK(&pool
->worker
, do_worker
);
1759 INIT_DELAYED_WORK(&pool
->waker
, do_waker
);
1760 spin_lock_init(&pool
->lock
);
1761 bio_list_init(&pool
->deferred_bios
);
1762 bio_list_init(&pool
->deferred_flush_bios
);
1763 INIT_LIST_HEAD(&pool
->prepared_mappings
);
1764 INIT_LIST_HEAD(&pool
->prepared_discards
);
1765 pool
->low_water_triggered
= 0;
1766 pool
->no_free_space
= 0;
1767 bio_list_init(&pool
->retry_on_resume_list
);
1769 pool
->shared_read_ds
= dm_deferred_set_create();
1770 if (!pool
->shared_read_ds
) {
1771 *error
= "Error creating pool's shared read deferred set";
1772 err_p
= ERR_PTR(-ENOMEM
);
1773 goto bad_shared_read_ds
;
1776 pool
->all_io_ds
= dm_deferred_set_create();
1777 if (!pool
->all_io_ds
) {
1778 *error
= "Error creating pool's all io deferred set";
1779 err_p
= ERR_PTR(-ENOMEM
);
1783 pool
->next_mapping
= NULL
;
1784 pool
->mapping_pool
= mempool_create_slab_pool(MAPPING_POOL_SIZE
,
1785 _new_mapping_cache
);
1786 if (!pool
->mapping_pool
) {
1787 *error
= "Error creating pool's mapping mempool";
1788 err_p
= ERR_PTR(-ENOMEM
);
1789 goto bad_mapping_pool
;
1792 pool
->ref_count
= 1;
1793 pool
->last_commit_jiffies
= jiffies
;
1794 pool
->pool_md
= pool_md
;
1795 pool
->md_dev
= metadata_dev
;
1796 __pool_table_insert(pool
);
1801 dm_deferred_set_destroy(pool
->all_io_ds
);
1803 dm_deferred_set_destroy(pool
->shared_read_ds
);
1805 destroy_workqueue(pool
->wq
);
1807 dm_kcopyd_client_destroy(pool
->copier
);
1809 dm_bio_prison_destroy(pool
->prison
);
1813 if (dm_pool_metadata_close(pmd
))
1814 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1819 static void __pool_inc(struct pool
*pool
)
1821 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1825 static void __pool_dec(struct pool
*pool
)
1827 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1828 BUG_ON(!pool
->ref_count
);
1829 if (!--pool
->ref_count
)
1830 __pool_destroy(pool
);
1833 static struct pool
*__pool_find(struct mapped_device
*pool_md
,
1834 struct block_device
*metadata_dev
,
1835 unsigned long block_size
, int read_only
,
1836 char **error
, int *created
)
1838 struct pool
*pool
= __pool_table_lookup_metadata_dev(metadata_dev
);
1841 if (pool
->pool_md
!= pool_md
) {
1842 *error
= "metadata device already in use by a pool";
1843 return ERR_PTR(-EBUSY
);
1848 pool
= __pool_table_lookup(pool_md
);
1850 if (pool
->md_dev
!= metadata_dev
) {
1851 *error
= "different pool cannot replace a pool";
1852 return ERR_PTR(-EINVAL
);
1857 pool
= pool_create(pool_md
, metadata_dev
, block_size
, read_only
, error
);
1865 /*----------------------------------------------------------------
1866 * Pool target methods
1867 *--------------------------------------------------------------*/
1868 static void pool_dtr(struct dm_target
*ti
)
1870 struct pool_c
*pt
= ti
->private;
1872 mutex_lock(&dm_thin_pool_table
.mutex
);
1874 unbind_control_target(pt
->pool
, ti
);
1875 __pool_dec(pt
->pool
);
1876 dm_put_device(ti
, pt
->metadata_dev
);
1877 dm_put_device(ti
, pt
->data_dev
);
1880 mutex_unlock(&dm_thin_pool_table
.mutex
);
1883 static int parse_pool_features(struct dm_arg_set
*as
, struct pool_features
*pf
,
1884 struct dm_target
*ti
)
1888 const char *arg_name
;
1890 static struct dm_arg _args
[] = {
1891 {0, 3, "Invalid number of pool feature arguments"},
1895 * No feature arguments supplied.
1900 r
= dm_read_arg_group(_args
, as
, &argc
, &ti
->error
);
1904 while (argc
&& !r
) {
1905 arg_name
= dm_shift_arg(as
);
1908 if (!strcasecmp(arg_name
, "skip_block_zeroing"))
1909 pf
->zero_new_blocks
= false;
1911 else if (!strcasecmp(arg_name
, "ignore_discard"))
1912 pf
->discard_enabled
= false;
1914 else if (!strcasecmp(arg_name
, "no_discard_passdown"))
1915 pf
->discard_passdown
= false;
1917 else if (!strcasecmp(arg_name
, "read_only"))
1918 pf
->mode
= PM_READ_ONLY
;
1921 ti
->error
= "Unrecognised pool feature requested";
1930 static void metadata_low_callback(void *context
)
1932 struct pool
*pool
= context
;
1934 DMWARN("%s: reached low water mark for metadata device: sending event.",
1935 dm_device_name(pool
->pool_md
));
1937 dm_table_event(pool
->ti
->table
);
1940 static sector_t
get_metadata_dev_size(struct block_device
*bdev
)
1942 sector_t metadata_dev_size
= i_size_read(bdev
->bd_inode
) >> SECTOR_SHIFT
;
1943 char buffer
[BDEVNAME_SIZE
];
1945 if (metadata_dev_size
> THIN_METADATA_MAX_SECTORS_WARNING
) {
1946 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1947 bdevname(bdev
, buffer
), THIN_METADATA_MAX_SECTORS
);
1948 metadata_dev_size
= THIN_METADATA_MAX_SECTORS_WARNING
;
1951 return metadata_dev_size
;
1954 static dm_block_t
get_metadata_dev_size_in_blocks(struct block_device
*bdev
)
1956 sector_t metadata_dev_size
= get_metadata_dev_size(bdev
);
1958 sector_div(metadata_dev_size
, THIN_METADATA_BLOCK_SIZE
>> SECTOR_SHIFT
);
1960 return metadata_dev_size
;
1964 * When a metadata threshold is crossed a dm event is triggered, and
1965 * userland should respond by growing the metadata device. We could let
1966 * userland set the threshold, like we do with the data threshold, but I'm
1967 * not sure they know enough to do this well.
1969 static dm_block_t
calc_metadata_threshold(struct pool_c
*pt
)
1972 * 4M is ample for all ops with the possible exception of thin
1973 * device deletion which is harmless if it fails (just retry the
1974 * delete after you've grown the device).
1976 dm_block_t quarter
= get_metadata_dev_size_in_blocks(pt
->metadata_dev
->bdev
) / 4;
1977 return min((dm_block_t
)1024ULL /* 4M */, quarter
);
1981 * thin-pool <metadata dev> <data dev>
1982 * <data block size (sectors)>
1983 * <low water mark (blocks)>
1984 * [<#feature args> [<arg>]*]
1986 * Optional feature arguments are:
1987 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1988 * ignore_discard: disable discard
1989 * no_discard_passdown: don't pass discards down to the data device
1991 static int pool_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
1993 int r
, pool_created
= 0;
1996 struct pool_features pf
;
1997 struct dm_arg_set as
;
1998 struct dm_dev
*data_dev
;
1999 unsigned long block_size
;
2000 dm_block_t low_water_blocks
;
2001 struct dm_dev
*metadata_dev
;
2002 fmode_t metadata_mode
;
2005 * FIXME Remove validation from scope of lock.
2007 mutex_lock(&dm_thin_pool_table
.mutex
);
2010 ti
->error
= "Invalid argument count";
2019 * Set default pool features.
2021 pool_features_init(&pf
);
2023 dm_consume_args(&as
, 4);
2024 r
= parse_pool_features(&as
, &pf
, ti
);
2028 metadata_mode
= FMODE_READ
| ((pf
.mode
== PM_READ_ONLY
) ? 0 : FMODE_WRITE
);
2029 r
= dm_get_device(ti
, argv
[0], metadata_mode
, &metadata_dev
);
2031 ti
->error
= "Error opening metadata block device";
2036 * Run for the side-effect of possibly issuing a warning if the
2037 * device is too big.
2039 (void) get_metadata_dev_size(metadata_dev
->bdev
);
2041 r
= dm_get_device(ti
, argv
[1], FMODE_READ
| FMODE_WRITE
, &data_dev
);
2043 ti
->error
= "Error getting data device";
2047 if (kstrtoul(argv
[2], 10, &block_size
) || !block_size
||
2048 block_size
< DATA_DEV_BLOCK_SIZE_MIN_SECTORS
||
2049 block_size
> DATA_DEV_BLOCK_SIZE_MAX_SECTORS
||
2050 block_size
& (DATA_DEV_BLOCK_SIZE_MIN_SECTORS
- 1)) {
2051 ti
->error
= "Invalid block size";
2056 if (kstrtoull(argv
[3], 10, (unsigned long long *)&low_water_blocks
)) {
2057 ti
->error
= "Invalid low water mark";
2062 pt
= kzalloc(sizeof(*pt
), GFP_KERNEL
);
2068 pool
= __pool_find(dm_table_get_md(ti
->table
), metadata_dev
->bdev
,
2069 block_size
, pf
.mode
== PM_READ_ONLY
, &ti
->error
, &pool_created
);
2076 * 'pool_created' reflects whether this is the first table load.
2077 * Top level discard support is not allowed to be changed after
2078 * initial load. This would require a pool reload to trigger thin
2081 if (!pool_created
&& pf
.discard_enabled
!= pool
->pf
.discard_enabled
) {
2082 ti
->error
= "Discard support cannot be disabled once enabled";
2084 goto out_flags_changed
;
2089 pt
->metadata_dev
= metadata_dev
;
2090 pt
->data_dev
= data_dev
;
2091 pt
->low_water_blocks
= low_water_blocks
;
2092 pt
->adjusted_pf
= pt
->requested_pf
= pf
;
2093 ti
->num_flush_bios
= 1;
2096 * Only need to enable discards if the pool should pass
2097 * them down to the data device. The thin device's discard
2098 * processing will cause mappings to be removed from the btree.
2100 ti
->discard_zeroes_data_unsupported
= true;
2101 if (pf
.discard_enabled
&& pf
.discard_passdown
) {
2102 ti
->num_discard_bios
= 1;
2105 * Setting 'discards_supported' circumvents the normal
2106 * stacking of discard limits (this keeps the pool and
2107 * thin devices' discard limits consistent).
2109 ti
->discards_supported
= true;
2113 r
= dm_pool_register_metadata_threshold(pt
->pool
->pmd
,
2114 calc_metadata_threshold(pt
),
2115 metadata_low_callback
,
2120 pt
->callbacks
.congested_fn
= pool_is_congested
;
2121 dm_table_add_target_callbacks(ti
->table
, &pt
->callbacks
);
2123 mutex_unlock(&dm_thin_pool_table
.mutex
);
2132 dm_put_device(ti
, data_dev
);
2134 dm_put_device(ti
, metadata_dev
);
2136 mutex_unlock(&dm_thin_pool_table
.mutex
);
2141 static int pool_map(struct dm_target
*ti
, struct bio
*bio
)
2144 struct pool_c
*pt
= ti
->private;
2145 struct pool
*pool
= pt
->pool
;
2146 unsigned long flags
;
2149 * As this is a singleton target, ti->begin is always zero.
2151 spin_lock_irqsave(&pool
->lock
, flags
);
2152 bio
->bi_bdev
= pt
->data_dev
->bdev
;
2153 r
= DM_MAPIO_REMAPPED
;
2154 spin_unlock_irqrestore(&pool
->lock
, flags
);
2159 static int maybe_resize_data_dev(struct dm_target
*ti
, bool *need_commit
)
2162 struct pool_c
*pt
= ti
->private;
2163 struct pool
*pool
= pt
->pool
;
2164 sector_t data_size
= ti
->len
;
2165 dm_block_t sb_data_size
;
2167 *need_commit
= false;
2169 (void) sector_div(data_size
, pool
->sectors_per_block
);
2171 r
= dm_pool_get_data_dev_size(pool
->pmd
, &sb_data_size
);
2173 DMERR("%s: failed to retrieve data device size",
2174 dm_device_name(pool
->pool_md
));
2178 if (data_size
< sb_data_size
) {
2179 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
2180 dm_device_name(pool
->pool_md
),
2181 (unsigned long long)data_size
, sb_data_size
);
2184 } else if (data_size
> sb_data_size
) {
2185 r
= dm_pool_resize_data_dev(pool
->pmd
, data_size
);
2187 DMERR("%s: failed to resize data device",
2188 dm_device_name(pool
->pool_md
));
2189 set_pool_mode(pool
, PM_READ_ONLY
);
2193 *need_commit
= true;
2199 static int maybe_resize_metadata_dev(struct dm_target
*ti
, bool *need_commit
)
2202 struct pool_c
*pt
= ti
->private;
2203 struct pool
*pool
= pt
->pool
;
2204 dm_block_t metadata_dev_size
, sb_metadata_dev_size
;
2206 *need_commit
= false;
2208 metadata_dev_size
= get_metadata_dev_size_in_blocks(pool
->md_dev
);
2210 r
= dm_pool_get_metadata_dev_size(pool
->pmd
, &sb_metadata_dev_size
);
2212 DMERR("%s: failed to retrieve metadata device size",
2213 dm_device_name(pool
->pool_md
));
2217 if (metadata_dev_size
< sb_metadata_dev_size
) {
2218 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
2219 dm_device_name(pool
->pool_md
),
2220 metadata_dev_size
, sb_metadata_dev_size
);
2223 } else if (metadata_dev_size
> sb_metadata_dev_size
) {
2224 r
= dm_pool_resize_metadata_dev(pool
->pmd
, metadata_dev_size
);
2226 DMERR("%s: failed to resize metadata device",
2227 dm_device_name(pool
->pool_md
));
2231 *need_commit
= true;
2238 * Retrieves the number of blocks of the data device from
2239 * the superblock and compares it to the actual device size,
2240 * thus resizing the data device in case it has grown.
2242 * This both copes with opening preallocated data devices in the ctr
2243 * being followed by a resume
2245 * calling the resume method individually after userspace has
2246 * grown the data device in reaction to a table event.
2248 static int pool_preresume(struct dm_target
*ti
)
2251 bool need_commit1
, need_commit2
;
2252 struct pool_c
*pt
= ti
->private;
2253 struct pool
*pool
= pt
->pool
;
2256 * Take control of the pool object.
2258 r
= bind_control_target(pool
, ti
);
2262 r
= maybe_resize_data_dev(ti
, &need_commit1
);
2266 r
= maybe_resize_metadata_dev(ti
, &need_commit2
);
2270 if (need_commit1
|| need_commit2
)
2271 (void) commit_or_fallback(pool
);
2276 static void pool_resume(struct dm_target
*ti
)
2278 struct pool_c
*pt
= ti
->private;
2279 struct pool
*pool
= pt
->pool
;
2280 unsigned long flags
;
2282 spin_lock_irqsave(&pool
->lock
, flags
);
2283 pool
->low_water_triggered
= 0;
2284 pool
->no_free_space
= 0;
2285 __requeue_bios(pool
);
2286 spin_unlock_irqrestore(&pool
->lock
, flags
);
2288 do_waker(&pool
->waker
.work
);
2291 static void pool_postsuspend(struct dm_target
*ti
)
2293 struct pool_c
*pt
= ti
->private;
2294 struct pool
*pool
= pt
->pool
;
2296 cancel_delayed_work(&pool
->waker
);
2297 flush_workqueue(pool
->wq
);
2298 (void) commit_or_fallback(pool
);
2301 static int check_arg_count(unsigned argc
, unsigned args_required
)
2303 if (argc
!= args_required
) {
2304 DMWARN("Message received with %u arguments instead of %u.",
2305 argc
, args_required
);
2312 static int read_dev_id(char *arg
, dm_thin_id
*dev_id
, int warning
)
2314 if (!kstrtoull(arg
, 10, (unsigned long long *)dev_id
) &&
2315 *dev_id
<= MAX_DEV_ID
)
2319 DMWARN("Message received with invalid device id: %s", arg
);
2324 static int process_create_thin_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2329 r
= check_arg_count(argc
, 2);
2333 r
= read_dev_id(argv
[1], &dev_id
, 1);
2337 r
= dm_pool_create_thin(pool
->pmd
, dev_id
);
2339 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2347 static int process_create_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2350 dm_thin_id origin_dev_id
;
2353 r
= check_arg_count(argc
, 3);
2357 r
= read_dev_id(argv
[1], &dev_id
, 1);
2361 r
= read_dev_id(argv
[2], &origin_dev_id
, 1);
2365 r
= dm_pool_create_snap(pool
->pmd
, dev_id
, origin_dev_id
);
2367 DMWARN("Creation of new snapshot %s of device %s failed.",
2375 static int process_delete_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2380 r
= check_arg_count(argc
, 2);
2384 r
= read_dev_id(argv
[1], &dev_id
, 1);
2388 r
= dm_pool_delete_thin_device(pool
->pmd
, dev_id
);
2390 DMWARN("Deletion of thin device %s failed.", argv
[1]);
2395 static int process_set_transaction_id_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2397 dm_thin_id old_id
, new_id
;
2400 r
= check_arg_count(argc
, 3);
2404 if (kstrtoull(argv
[1], 10, (unsigned long long *)&old_id
)) {
2405 DMWARN("set_transaction_id message: Unrecognised id %s.", argv
[1]);
2409 if (kstrtoull(argv
[2], 10, (unsigned long long *)&new_id
)) {
2410 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv
[2]);
2414 r
= dm_pool_set_metadata_transaction_id(pool
->pmd
, old_id
, new_id
);
2416 DMWARN("Failed to change transaction id from %s to %s.",
2424 static int process_reserve_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2428 r
= check_arg_count(argc
, 1);
2432 (void) commit_or_fallback(pool
);
2434 r
= dm_pool_reserve_metadata_snap(pool
->pmd
);
2436 DMWARN("reserve_metadata_snap message failed.");
2441 static int process_release_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2445 r
= check_arg_count(argc
, 1);
2449 r
= dm_pool_release_metadata_snap(pool
->pmd
);
2451 DMWARN("release_metadata_snap message failed.");
2457 * Messages supported:
2458 * create_thin <dev_id>
2459 * create_snap <dev_id> <origin_id>
2461 * trim <dev_id> <new_size_in_sectors>
2462 * set_transaction_id <current_trans_id> <new_trans_id>
2463 * reserve_metadata_snap
2464 * release_metadata_snap
2466 static int pool_message(struct dm_target
*ti
, unsigned argc
, char **argv
)
2469 struct pool_c
*pt
= ti
->private;
2470 struct pool
*pool
= pt
->pool
;
2472 if (!strcasecmp(argv
[0], "create_thin"))
2473 r
= process_create_thin_mesg(argc
, argv
, pool
);
2475 else if (!strcasecmp(argv
[0], "create_snap"))
2476 r
= process_create_snap_mesg(argc
, argv
, pool
);
2478 else if (!strcasecmp(argv
[0], "delete"))
2479 r
= process_delete_mesg(argc
, argv
, pool
);
2481 else if (!strcasecmp(argv
[0], "set_transaction_id"))
2482 r
= process_set_transaction_id_mesg(argc
, argv
, pool
);
2484 else if (!strcasecmp(argv
[0], "reserve_metadata_snap"))
2485 r
= process_reserve_metadata_snap_mesg(argc
, argv
, pool
);
2487 else if (!strcasecmp(argv
[0], "release_metadata_snap"))
2488 r
= process_release_metadata_snap_mesg(argc
, argv
, pool
);
2491 DMWARN("Unrecognised thin pool target message received: %s", argv
[0]);
2494 (void) commit_or_fallback(pool
);
2499 static void emit_flags(struct pool_features
*pf
, char *result
,
2500 unsigned sz
, unsigned maxlen
)
2502 unsigned count
= !pf
->zero_new_blocks
+ !pf
->discard_enabled
+
2503 !pf
->discard_passdown
+ (pf
->mode
== PM_READ_ONLY
);
2504 DMEMIT("%u ", count
);
2506 if (!pf
->zero_new_blocks
)
2507 DMEMIT("skip_block_zeroing ");
2509 if (!pf
->discard_enabled
)
2510 DMEMIT("ignore_discard ");
2512 if (!pf
->discard_passdown
)
2513 DMEMIT("no_discard_passdown ");
2515 if (pf
->mode
== PM_READ_ONLY
)
2516 DMEMIT("read_only ");
2521 * <transaction id> <used metadata sectors>/<total metadata sectors>
2522 * <used data sectors>/<total data sectors> <held metadata root>
2524 static void pool_status(struct dm_target
*ti
, status_type_t type
,
2525 unsigned status_flags
, char *result
, unsigned maxlen
)
2529 uint64_t transaction_id
;
2530 dm_block_t nr_free_blocks_data
;
2531 dm_block_t nr_free_blocks_metadata
;
2532 dm_block_t nr_blocks_data
;
2533 dm_block_t nr_blocks_metadata
;
2534 dm_block_t held_root
;
2535 char buf
[BDEVNAME_SIZE
];
2536 char buf2
[BDEVNAME_SIZE
];
2537 struct pool_c
*pt
= ti
->private;
2538 struct pool
*pool
= pt
->pool
;
2541 case STATUSTYPE_INFO
:
2542 if (get_pool_mode(pool
) == PM_FAIL
) {
2547 /* Commit to ensure statistics aren't out-of-date */
2548 if (!(status_flags
& DM_STATUS_NOFLUSH_FLAG
) && !dm_suspended(ti
))
2549 (void) commit_or_fallback(pool
);
2551 r
= dm_pool_get_metadata_transaction_id(pool
->pmd
, &transaction_id
);
2553 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
2554 dm_device_name(pool
->pool_md
), r
);
2558 r
= dm_pool_get_free_metadata_block_count(pool
->pmd
, &nr_free_blocks_metadata
);
2560 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
2561 dm_device_name(pool
->pool_md
), r
);
2565 r
= dm_pool_get_metadata_dev_size(pool
->pmd
, &nr_blocks_metadata
);
2567 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
2568 dm_device_name(pool
->pool_md
), r
);
2572 r
= dm_pool_get_free_block_count(pool
->pmd
, &nr_free_blocks_data
);
2574 DMERR("%s: dm_pool_get_free_block_count returned %d",
2575 dm_device_name(pool
->pool_md
), r
);
2579 r
= dm_pool_get_data_dev_size(pool
->pmd
, &nr_blocks_data
);
2581 DMERR("%s: dm_pool_get_data_dev_size returned %d",
2582 dm_device_name(pool
->pool_md
), r
);
2586 r
= dm_pool_get_metadata_snap(pool
->pmd
, &held_root
);
2588 DMERR("%s: dm_pool_get_metadata_snap returned %d",
2589 dm_device_name(pool
->pool_md
), r
);
2593 DMEMIT("%llu %llu/%llu %llu/%llu ",
2594 (unsigned long long)transaction_id
,
2595 (unsigned long long)(nr_blocks_metadata
- nr_free_blocks_metadata
),
2596 (unsigned long long)nr_blocks_metadata
,
2597 (unsigned long long)(nr_blocks_data
- nr_free_blocks_data
),
2598 (unsigned long long)nr_blocks_data
);
2601 DMEMIT("%llu ", held_root
);
2605 if (pool
->pf
.mode
== PM_READ_ONLY
)
2610 if (!pool
->pf
.discard_enabled
)
2611 DMEMIT("ignore_discard");
2612 else if (pool
->pf
.discard_passdown
)
2613 DMEMIT("discard_passdown");
2615 DMEMIT("no_discard_passdown");
2619 case STATUSTYPE_TABLE
:
2620 DMEMIT("%s %s %lu %llu ",
2621 format_dev_t(buf
, pt
->metadata_dev
->bdev
->bd_dev
),
2622 format_dev_t(buf2
, pt
->data_dev
->bdev
->bd_dev
),
2623 (unsigned long)pool
->sectors_per_block
,
2624 (unsigned long long)pt
->low_water_blocks
);
2625 emit_flags(&pt
->requested_pf
, result
, sz
, maxlen
);
2634 static int pool_iterate_devices(struct dm_target
*ti
,
2635 iterate_devices_callout_fn fn
, void *data
)
2637 struct pool_c
*pt
= ti
->private;
2639 return fn(ti
, pt
->data_dev
, 0, ti
->len
, data
);
2642 static int pool_merge(struct dm_target
*ti
, struct bvec_merge_data
*bvm
,
2643 struct bio_vec
*biovec
, int max_size
)
2645 struct pool_c
*pt
= ti
->private;
2646 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
2648 if (!q
->merge_bvec_fn
)
2651 bvm
->bi_bdev
= pt
->data_dev
->bdev
;
2653 return min(max_size
, q
->merge_bvec_fn(q
, bvm
, biovec
));
2656 static void set_discard_limits(struct pool_c
*pt
, struct queue_limits
*limits
)
2658 struct pool
*pool
= pt
->pool
;
2659 struct queue_limits
*data_limits
;
2661 limits
->max_discard_sectors
= pool
->sectors_per_block
;
2664 * discard_granularity is just a hint, and not enforced.
2666 if (pt
->adjusted_pf
.discard_passdown
) {
2667 data_limits
= &bdev_get_queue(pt
->data_dev
->bdev
)->limits
;
2668 limits
->discard_granularity
= data_limits
->discard_granularity
;
2670 limits
->discard_granularity
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
2673 static void pool_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
2675 struct pool_c
*pt
= ti
->private;
2676 struct pool
*pool
= pt
->pool
;
2677 uint64_t io_opt_sectors
= limits
->io_opt
>> SECTOR_SHIFT
;
2680 * If the system-determined stacked limits are compatible with the
2681 * pool's blocksize (io_opt is a factor) do not override them.
2683 if (io_opt_sectors
< pool
->sectors_per_block
||
2684 do_div(io_opt_sectors
, pool
->sectors_per_block
)) {
2685 blk_limits_io_min(limits
, 0);
2686 blk_limits_io_opt(limits
, pool
->sectors_per_block
<< SECTOR_SHIFT
);
2690 * pt->adjusted_pf is a staging area for the actual features to use.
2691 * They get transferred to the live pool in bind_control_target()
2692 * called from pool_preresume().
2694 if (!pt
->adjusted_pf
.discard_enabled
) {
2696 * Must explicitly disallow stacking discard limits otherwise the
2697 * block layer will stack them if pool's data device has support.
2698 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
2699 * user to see that, so make sure to set all discard limits to 0.
2701 limits
->discard_granularity
= 0;
2705 disable_passdown_if_not_supported(pt
);
2707 set_discard_limits(pt
, limits
);
2710 static struct target_type pool_target
= {
2711 .name
= "thin-pool",
2712 .features
= DM_TARGET_SINGLETON
| DM_TARGET_ALWAYS_WRITEABLE
|
2713 DM_TARGET_IMMUTABLE
,
2714 .version
= {1, 9, 0},
2715 .module
= THIS_MODULE
,
2719 .postsuspend
= pool_postsuspend
,
2720 .preresume
= pool_preresume
,
2721 .resume
= pool_resume
,
2722 .message
= pool_message
,
2723 .status
= pool_status
,
2724 .merge
= pool_merge
,
2725 .iterate_devices
= pool_iterate_devices
,
2726 .io_hints
= pool_io_hints
,
2729 /*----------------------------------------------------------------
2730 * Thin target methods
2731 *--------------------------------------------------------------*/
2732 static void thin_dtr(struct dm_target
*ti
)
2734 struct thin_c
*tc
= ti
->private;
2736 mutex_lock(&dm_thin_pool_table
.mutex
);
2738 __pool_dec(tc
->pool
);
2739 dm_pool_close_thin_device(tc
->td
);
2740 dm_put_device(ti
, tc
->pool_dev
);
2742 dm_put_device(ti
, tc
->origin_dev
);
2745 mutex_unlock(&dm_thin_pool_table
.mutex
);
2749 * Thin target parameters:
2751 * <pool_dev> <dev_id> [origin_dev]
2753 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2754 * dev_id: the internal device identifier
2755 * origin_dev: a device external to the pool that should act as the origin
2757 * If the pool device has discards disabled, they get disabled for the thin
2760 static int thin_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
2764 struct dm_dev
*pool_dev
, *origin_dev
;
2765 struct mapped_device
*pool_md
;
2767 mutex_lock(&dm_thin_pool_table
.mutex
);
2769 if (argc
!= 2 && argc
!= 3) {
2770 ti
->error
= "Invalid argument count";
2775 tc
= ti
->private = kzalloc(sizeof(*tc
), GFP_KERNEL
);
2777 ti
->error
= "Out of memory";
2783 r
= dm_get_device(ti
, argv
[2], FMODE_READ
, &origin_dev
);
2785 ti
->error
= "Error opening origin device";
2786 goto bad_origin_dev
;
2788 tc
->origin_dev
= origin_dev
;
2791 r
= dm_get_device(ti
, argv
[0], dm_table_get_mode(ti
->table
), &pool_dev
);
2793 ti
->error
= "Error opening pool device";
2796 tc
->pool_dev
= pool_dev
;
2798 if (read_dev_id(argv
[1], (unsigned long long *)&tc
->dev_id
, 0)) {
2799 ti
->error
= "Invalid device id";
2804 pool_md
= dm_get_md(tc
->pool_dev
->bdev
->bd_dev
);
2806 ti
->error
= "Couldn't get pool mapped device";
2811 tc
->pool
= __pool_table_lookup(pool_md
);
2813 ti
->error
= "Couldn't find pool object";
2815 goto bad_pool_lookup
;
2817 __pool_inc(tc
->pool
);
2819 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
2820 ti
->error
= "Couldn't open thin device, Pool is in fail mode";
2824 r
= dm_pool_open_thin_device(tc
->pool
->pmd
, tc
->dev_id
, &tc
->td
);
2826 ti
->error
= "Couldn't open thin internal device";
2830 r
= dm_set_target_max_io_len(ti
, tc
->pool
->sectors_per_block
);
2834 ti
->num_flush_bios
= 1;
2835 ti
->flush_supported
= true;
2836 ti
->per_bio_data_size
= sizeof(struct dm_thin_endio_hook
);
2838 /* In case the pool supports discards, pass them on. */
2839 ti
->discard_zeroes_data_unsupported
= true;
2840 if (tc
->pool
->pf
.discard_enabled
) {
2841 ti
->discards_supported
= true;
2842 ti
->num_discard_bios
= 1;
2843 /* Discard bios must be split on a block boundary */
2844 ti
->split_discard_bios
= true;
2849 mutex_unlock(&dm_thin_pool_table
.mutex
);
2854 __pool_dec(tc
->pool
);
2858 dm_put_device(ti
, tc
->pool_dev
);
2861 dm_put_device(ti
, tc
->origin_dev
);
2865 mutex_unlock(&dm_thin_pool_table
.mutex
);
2870 static int thin_map(struct dm_target
*ti
, struct bio
*bio
)
2872 bio
->bi_iter
.bi_sector
= dm_target_offset(ti
, bio
->bi_iter
.bi_sector
);
2874 return thin_bio_map(ti
, bio
);
2877 static int thin_endio(struct dm_target
*ti
, struct bio
*bio
, int err
)
2879 unsigned long flags
;
2880 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
2881 struct list_head work
;
2882 struct dm_thin_new_mapping
*m
, *tmp
;
2883 struct pool
*pool
= h
->tc
->pool
;
2885 if (h
->shared_read_entry
) {
2886 INIT_LIST_HEAD(&work
);
2887 dm_deferred_entry_dec(h
->shared_read_entry
, &work
);
2889 spin_lock_irqsave(&pool
->lock
, flags
);
2890 list_for_each_entry_safe(m
, tmp
, &work
, list
) {
2893 __maybe_add_mapping(m
);
2895 spin_unlock_irqrestore(&pool
->lock
, flags
);
2898 if (h
->all_io_entry
) {
2899 INIT_LIST_HEAD(&work
);
2900 dm_deferred_entry_dec(h
->all_io_entry
, &work
);
2901 if (!list_empty(&work
)) {
2902 spin_lock_irqsave(&pool
->lock
, flags
);
2903 list_for_each_entry_safe(m
, tmp
, &work
, list
)
2904 list_add(&m
->list
, &pool
->prepared_discards
);
2905 spin_unlock_irqrestore(&pool
->lock
, flags
);
2913 static void thin_postsuspend(struct dm_target
*ti
)
2915 if (dm_noflush_suspending(ti
))
2916 requeue_io((struct thin_c
*)ti
->private);
2920 * <nr mapped sectors> <highest mapped sector>
2922 static void thin_status(struct dm_target
*ti
, status_type_t type
,
2923 unsigned status_flags
, char *result
, unsigned maxlen
)
2927 dm_block_t mapped
, highest
;
2928 char buf
[BDEVNAME_SIZE
];
2929 struct thin_c
*tc
= ti
->private;
2931 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
2940 case STATUSTYPE_INFO
:
2941 r
= dm_thin_get_mapped_count(tc
->td
, &mapped
);
2943 DMERR("dm_thin_get_mapped_count returned %d", r
);
2947 r
= dm_thin_get_highest_mapped_block(tc
->td
, &highest
);
2949 DMERR("dm_thin_get_highest_mapped_block returned %d", r
);
2953 DMEMIT("%llu ", mapped
* tc
->pool
->sectors_per_block
);
2955 DMEMIT("%llu", ((highest
+ 1) *
2956 tc
->pool
->sectors_per_block
) - 1);
2961 case STATUSTYPE_TABLE
:
2963 format_dev_t(buf
, tc
->pool_dev
->bdev
->bd_dev
),
2964 (unsigned long) tc
->dev_id
);
2966 DMEMIT(" %s", format_dev_t(buf
, tc
->origin_dev
->bdev
->bd_dev
));
2977 static int thin_iterate_devices(struct dm_target
*ti
,
2978 iterate_devices_callout_fn fn
, void *data
)
2981 struct thin_c
*tc
= ti
->private;
2982 struct pool
*pool
= tc
->pool
;
2985 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2986 * we follow a more convoluted path through to the pool's target.
2989 return 0; /* nothing is bound */
2991 blocks
= pool
->ti
->len
;
2992 (void) sector_div(blocks
, pool
->sectors_per_block
);
2994 return fn(ti
, tc
->pool_dev
, 0, pool
->sectors_per_block
* blocks
, data
);
2999 static struct target_type thin_target
= {
3001 .version
= {1, 9, 0},
3002 .module
= THIS_MODULE
,
3006 .end_io
= thin_endio
,
3007 .postsuspend
= thin_postsuspend
,
3008 .status
= thin_status
,
3009 .iterate_devices
= thin_iterate_devices
,
3012 /*----------------------------------------------------------------*/
3014 static int __init
dm_thin_init(void)
3020 r
= dm_register_target(&thin_target
);
3024 r
= dm_register_target(&pool_target
);
3026 goto bad_pool_target
;
3030 _new_mapping_cache
= KMEM_CACHE(dm_thin_new_mapping
, 0);
3031 if (!_new_mapping_cache
)
3032 goto bad_new_mapping_cache
;
3036 bad_new_mapping_cache
:
3037 dm_unregister_target(&pool_target
);
3039 dm_unregister_target(&thin_target
);
3044 static void dm_thin_exit(void)
3046 dm_unregister_target(&thin_target
);
3047 dm_unregister_target(&pool_target
);
3049 kmem_cache_destroy(_new_mapping_cache
);
3052 module_init(dm_thin_init
);
3053 module_exit(dm_thin_exit
);
3055 MODULE_DESCRIPTION(DM_NAME
" thin provisioning target");
3056 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3057 MODULE_LICENSE("GPL");