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;
147 bool error_if_no_space
:1;
151 typedef void (*process_bio_fn
)(struct thin_c
*tc
, struct bio
*bio
);
152 typedef void (*process_mapping_fn
)(struct dm_thin_new_mapping
*m
);
155 struct list_head list
;
156 struct dm_target
*ti
; /* Only set if a pool target is bound */
158 struct mapped_device
*pool_md
;
159 struct block_device
*md_dev
;
160 struct dm_pool_metadata
*pmd
;
162 dm_block_t low_water_blocks
;
163 uint32_t sectors_per_block
;
164 int sectors_per_block_shift
;
166 struct pool_features pf
;
167 bool low_water_triggered
:1; /* A dm event has been sent */
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 out_of_data_space(struct pool
*pool
);
202 static void metadata_operation_failed(struct pool
*pool
, const char *op
, int r
);
205 * Target context for a pool.
208 struct dm_target
*ti
;
210 struct dm_dev
*data_dev
;
211 struct dm_dev
*metadata_dev
;
212 struct dm_target_callbacks callbacks
;
214 dm_block_t low_water_blocks
;
215 struct pool_features requested_pf
; /* Features requested during table load */
216 struct pool_features adjusted_pf
; /* Features used after adjusting for constituent devices */
220 * Target context for a thin.
223 struct dm_dev
*pool_dev
;
224 struct dm_dev
*origin_dev
;
228 struct dm_thin_device
*td
;
231 /*----------------------------------------------------------------*/
234 * wake_worker() is used when new work is queued and when pool_resume is
235 * ready to continue deferred IO processing.
237 static void wake_worker(struct pool
*pool
)
239 queue_work(pool
->wq
, &pool
->worker
);
242 /*----------------------------------------------------------------*/
244 static int bio_detain(struct pool
*pool
, struct dm_cell_key
*key
, struct bio
*bio
,
245 struct dm_bio_prison_cell
**cell_result
)
248 struct dm_bio_prison_cell
*cell_prealloc
;
251 * Allocate a cell from the prison's mempool.
252 * This might block but it can't fail.
254 cell_prealloc
= dm_bio_prison_alloc_cell(pool
->prison
, GFP_NOIO
);
256 r
= dm_bio_detain(pool
->prison
, key
, bio
, cell_prealloc
, cell_result
);
259 * We reused an old cell; we can get rid of
262 dm_bio_prison_free_cell(pool
->prison
, cell_prealloc
);
267 static void cell_release(struct pool
*pool
,
268 struct dm_bio_prison_cell
*cell
,
269 struct bio_list
*bios
)
271 dm_cell_release(pool
->prison
, cell
, bios
);
272 dm_bio_prison_free_cell(pool
->prison
, cell
);
275 static void cell_release_no_holder(struct pool
*pool
,
276 struct dm_bio_prison_cell
*cell
,
277 struct bio_list
*bios
)
279 dm_cell_release_no_holder(pool
->prison
, cell
, bios
);
280 dm_bio_prison_free_cell(pool
->prison
, cell
);
283 static void cell_defer_no_holder_no_free(struct thin_c
*tc
,
284 struct dm_bio_prison_cell
*cell
)
286 struct pool
*pool
= tc
->pool
;
289 spin_lock_irqsave(&pool
->lock
, flags
);
290 dm_cell_release_no_holder(pool
->prison
, cell
, &pool
->deferred_bios
);
291 spin_unlock_irqrestore(&pool
->lock
, flags
);
296 static void cell_error(struct pool
*pool
,
297 struct dm_bio_prison_cell
*cell
)
299 dm_cell_error(pool
->prison
, cell
);
300 dm_bio_prison_free_cell(pool
->prison
, cell
);
303 /*----------------------------------------------------------------*/
306 * A global list of pools that uses a struct mapped_device as a key.
308 static struct dm_thin_pool_table
{
310 struct list_head pools
;
311 } dm_thin_pool_table
;
313 static void pool_table_init(void)
315 mutex_init(&dm_thin_pool_table
.mutex
);
316 INIT_LIST_HEAD(&dm_thin_pool_table
.pools
);
319 static void __pool_table_insert(struct pool
*pool
)
321 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
322 list_add(&pool
->list
, &dm_thin_pool_table
.pools
);
325 static void __pool_table_remove(struct pool
*pool
)
327 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
328 list_del(&pool
->list
);
331 static struct pool
*__pool_table_lookup(struct mapped_device
*md
)
333 struct pool
*pool
= NULL
, *tmp
;
335 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
337 list_for_each_entry(tmp
, &dm_thin_pool_table
.pools
, list
) {
338 if (tmp
->pool_md
== md
) {
347 static struct pool
*__pool_table_lookup_metadata_dev(struct block_device
*md_dev
)
349 struct pool
*pool
= NULL
, *tmp
;
351 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
353 list_for_each_entry(tmp
, &dm_thin_pool_table
.pools
, list
) {
354 if (tmp
->md_dev
== md_dev
) {
363 /*----------------------------------------------------------------*/
365 struct dm_thin_endio_hook
{
367 struct dm_deferred_entry
*shared_read_entry
;
368 struct dm_deferred_entry
*all_io_entry
;
369 struct dm_thin_new_mapping
*overwrite_mapping
;
372 static void __requeue_bio_list(struct thin_c
*tc
, struct bio_list
*master
)
375 struct bio_list bios
;
377 bio_list_init(&bios
);
378 bio_list_merge(&bios
, master
);
379 bio_list_init(master
);
381 while ((bio
= bio_list_pop(&bios
))) {
382 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
385 bio_endio(bio
, DM_ENDIO_REQUEUE
);
387 bio_list_add(master
, bio
);
391 static void requeue_io(struct thin_c
*tc
)
393 struct pool
*pool
= tc
->pool
;
396 spin_lock_irqsave(&pool
->lock
, flags
);
397 __requeue_bio_list(tc
, &pool
->deferred_bios
);
398 __requeue_bio_list(tc
, &pool
->retry_on_resume_list
);
399 spin_unlock_irqrestore(&pool
->lock
, flags
);
403 * This section of code contains the logic for processing a thin device's IO.
404 * Much of the code depends on pool object resources (lists, workqueues, etc)
405 * but most is exclusively called from the thin target rather than the thin-pool
409 static bool block_size_is_power_of_two(struct pool
*pool
)
411 return pool
->sectors_per_block_shift
>= 0;
414 static dm_block_t
get_bio_block(struct thin_c
*tc
, struct bio
*bio
)
416 struct pool
*pool
= tc
->pool
;
417 sector_t block_nr
= bio
->bi_sector
;
419 if (block_size_is_power_of_two(pool
))
420 block_nr
>>= pool
->sectors_per_block_shift
;
422 (void) sector_div(block_nr
, pool
->sectors_per_block
);
427 static void remap(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
)
429 struct pool
*pool
= tc
->pool
;
430 sector_t bi_sector
= bio
->bi_sector
;
432 bio
->bi_bdev
= tc
->pool_dev
->bdev
;
433 if (block_size_is_power_of_two(pool
))
434 bio
->bi_sector
= (block
<< pool
->sectors_per_block_shift
) |
435 (bi_sector
& (pool
->sectors_per_block
- 1));
437 bio
->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
;
516 bool definitely_not_shared
:1;
520 dm_block_t virt_block
;
521 dm_block_t data_block
;
522 struct dm_bio_prison_cell
*cell
, *cell2
;
525 * If the bio covers the whole area of a block then we can avoid
526 * zeroing or copying. Instead this bio is hooked. The bio will
527 * still be in the cell, so care has to be taken to avoid issuing
531 bio_end_io_t
*saved_bi_end_io
;
534 static void __maybe_add_mapping(struct dm_thin_new_mapping
*m
)
536 struct pool
*pool
= m
->tc
->pool
;
538 if (m
->quiesced
&& m
->prepared
) {
539 list_add_tail(&m
->list
, &pool
->prepared_mappings
);
544 static void copy_complete(int read_err
, unsigned long write_err
, void *context
)
547 struct dm_thin_new_mapping
*m
= context
;
548 struct pool
*pool
= m
->tc
->pool
;
550 m
->err
= read_err
|| write_err
? -EIO
: 0;
552 spin_lock_irqsave(&pool
->lock
, flags
);
554 __maybe_add_mapping(m
);
555 spin_unlock_irqrestore(&pool
->lock
, flags
);
558 static void overwrite_endio(struct bio
*bio
, int err
)
561 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
562 struct dm_thin_new_mapping
*m
= h
->overwrite_mapping
;
563 struct pool
*pool
= m
->tc
->pool
;
567 spin_lock_irqsave(&pool
->lock
, flags
);
569 __maybe_add_mapping(m
);
570 spin_unlock_irqrestore(&pool
->lock
, flags
);
573 /*----------------------------------------------------------------*/
580 * Prepared mapping jobs.
584 * This sends the bios in the cell back to the deferred_bios list.
586 static void cell_defer(struct thin_c
*tc
, struct dm_bio_prison_cell
*cell
)
588 struct pool
*pool
= tc
->pool
;
591 spin_lock_irqsave(&pool
->lock
, flags
);
592 cell_release(pool
, cell
, &pool
->deferred_bios
);
593 spin_unlock_irqrestore(&tc
->pool
->lock
, flags
);
599 * Same as cell_defer above, except it omits the original holder of the cell.
601 static void cell_defer_no_holder(struct thin_c
*tc
, struct dm_bio_prison_cell
*cell
)
603 struct pool
*pool
= tc
->pool
;
606 spin_lock_irqsave(&pool
->lock
, flags
);
607 cell_release_no_holder(pool
, cell
, &pool
->deferred_bios
);
608 spin_unlock_irqrestore(&pool
->lock
, flags
);
613 static void process_prepared_mapping_fail(struct dm_thin_new_mapping
*m
)
616 m
->bio
->bi_end_io
= m
->saved_bi_end_io
;
617 cell_error(m
->tc
->pool
, m
->cell
);
619 mempool_free(m
, m
->tc
->pool
->mapping_pool
);
622 static void process_prepared_mapping(struct dm_thin_new_mapping
*m
)
624 struct thin_c
*tc
= m
->tc
;
625 struct pool
*pool
= tc
->pool
;
631 bio
->bi_end_io
= m
->saved_bi_end_io
;
634 cell_error(pool
, m
->cell
);
639 * Commit the prepared block into the mapping btree.
640 * Any I/O for this block arriving after this point will get
641 * remapped to it directly.
643 r
= dm_thin_insert_block(tc
->td
, m
->virt_block
, m
->data_block
);
645 metadata_operation_failed(pool
, "dm_thin_insert_block", r
);
646 cell_error(pool
, m
->cell
);
651 * Release any bios held while the block was being provisioned.
652 * If we are processing a write bio that completely covers the block,
653 * we already processed it so can ignore it now when processing
654 * the bios in the cell.
657 cell_defer_no_holder(tc
, m
->cell
);
660 cell_defer(tc
, m
->cell
);
664 mempool_free(m
, pool
->mapping_pool
);
667 static void process_prepared_discard_fail(struct dm_thin_new_mapping
*m
)
669 struct thin_c
*tc
= m
->tc
;
671 bio_io_error(m
->bio
);
672 cell_defer_no_holder(tc
, m
->cell
);
673 cell_defer_no_holder(tc
, m
->cell2
);
674 mempool_free(m
, tc
->pool
->mapping_pool
);
677 static void process_prepared_discard_passdown(struct dm_thin_new_mapping
*m
)
679 struct thin_c
*tc
= m
->tc
;
681 inc_all_io_entry(tc
->pool
, m
->bio
);
682 cell_defer_no_holder(tc
, m
->cell
);
683 cell_defer_no_holder(tc
, m
->cell2
);
686 if (m
->definitely_not_shared
)
687 remap_and_issue(tc
, m
->bio
, m
->data_block
);
690 if (dm_pool_block_is_used(tc
->pool
->pmd
, m
->data_block
, &used
) || used
)
691 bio_endio(m
->bio
, 0);
693 remap_and_issue(tc
, m
->bio
, m
->data_block
);
696 bio_endio(m
->bio
, 0);
698 mempool_free(m
, tc
->pool
->mapping_pool
);
701 static void process_prepared_discard(struct dm_thin_new_mapping
*m
)
704 struct thin_c
*tc
= m
->tc
;
706 r
= dm_thin_remove_block(tc
->td
, m
->virt_block
);
708 DMERR_LIMIT("dm_thin_remove_block() failed");
710 process_prepared_discard_passdown(m
);
713 static void process_prepared(struct pool
*pool
, struct list_head
*head
,
714 process_mapping_fn
*fn
)
717 struct list_head maps
;
718 struct dm_thin_new_mapping
*m
, *tmp
;
720 INIT_LIST_HEAD(&maps
);
721 spin_lock_irqsave(&pool
->lock
, flags
);
722 list_splice_init(head
, &maps
);
723 spin_unlock_irqrestore(&pool
->lock
, flags
);
725 list_for_each_entry_safe(m
, tmp
, &maps
, list
)
732 static int io_overlaps_block(struct pool
*pool
, struct bio
*bio
)
734 return bio
->bi_size
== (pool
->sectors_per_block
<< SECTOR_SHIFT
);
737 static int io_overwrites_block(struct pool
*pool
, struct bio
*bio
)
739 return (bio_data_dir(bio
) == WRITE
) &&
740 io_overlaps_block(pool
, bio
);
743 static void save_and_set_endio(struct bio
*bio
, bio_end_io_t
**save
,
746 *save
= bio
->bi_end_io
;
750 static int ensure_next_mapping(struct pool
*pool
)
752 if (pool
->next_mapping
)
755 pool
->next_mapping
= mempool_alloc(pool
->mapping_pool
, GFP_ATOMIC
);
757 return pool
->next_mapping
? 0 : -ENOMEM
;
760 static struct dm_thin_new_mapping
*get_next_mapping(struct pool
*pool
)
762 struct dm_thin_new_mapping
*m
= pool
->next_mapping
;
764 BUG_ON(!pool
->next_mapping
);
766 memset(m
, 0, sizeof(struct dm_thin_new_mapping
));
767 INIT_LIST_HEAD(&m
->list
);
770 pool
->next_mapping
= NULL
;
775 static void schedule_copy(struct thin_c
*tc
, dm_block_t virt_block
,
776 struct dm_dev
*origin
, dm_block_t data_origin
,
777 dm_block_t data_dest
,
778 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
781 struct pool
*pool
= tc
->pool
;
782 struct dm_thin_new_mapping
*m
= get_next_mapping(pool
);
785 m
->virt_block
= virt_block
;
786 m
->data_block
= data_dest
;
789 if (!dm_deferred_set_add_work(pool
->shared_read_ds
, &m
->list
))
793 * IO to pool_dev remaps to the pool target's data_dev.
795 * If the whole block of data is being overwritten, we can issue the
796 * bio immediately. Otherwise we use kcopyd to clone the data first.
798 if (io_overwrites_block(pool
, bio
)) {
799 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
801 h
->overwrite_mapping
= m
;
803 save_and_set_endio(bio
, &m
->saved_bi_end_io
, overwrite_endio
);
804 inc_all_io_entry(pool
, bio
);
805 remap_and_issue(tc
, bio
, data_dest
);
807 struct dm_io_region from
, to
;
809 from
.bdev
= origin
->bdev
;
810 from
.sector
= data_origin
* pool
->sectors_per_block
;
811 from
.count
= pool
->sectors_per_block
;
813 to
.bdev
= tc
->pool_dev
->bdev
;
814 to
.sector
= data_dest
* pool
->sectors_per_block
;
815 to
.count
= pool
->sectors_per_block
;
817 r
= dm_kcopyd_copy(pool
->copier
, &from
, 1, &to
,
818 0, copy_complete
, m
);
820 mempool_free(m
, pool
->mapping_pool
);
821 DMERR_LIMIT("dm_kcopyd_copy() failed");
822 cell_error(pool
, cell
);
827 static void schedule_internal_copy(struct thin_c
*tc
, dm_block_t virt_block
,
828 dm_block_t data_origin
, dm_block_t data_dest
,
829 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
831 schedule_copy(tc
, virt_block
, tc
->pool_dev
,
832 data_origin
, data_dest
, cell
, bio
);
835 static void schedule_external_copy(struct thin_c
*tc
, dm_block_t virt_block
,
836 dm_block_t data_dest
,
837 struct dm_bio_prison_cell
*cell
, struct bio
*bio
)
839 schedule_copy(tc
, virt_block
, tc
->origin_dev
,
840 virt_block
, data_dest
, cell
, bio
);
843 static void schedule_zero(struct thin_c
*tc
, dm_block_t virt_block
,
844 dm_block_t data_block
, struct dm_bio_prison_cell
*cell
,
847 struct pool
*pool
= tc
->pool
;
848 struct dm_thin_new_mapping
*m
= get_next_mapping(pool
);
853 m
->virt_block
= virt_block
;
854 m
->data_block
= data_block
;
858 * If the whole block of data is being overwritten or we are not
859 * zeroing pre-existing data, we can issue the bio immediately.
860 * Otherwise we use kcopyd to zero the data first.
862 if (!pool
->pf
.zero_new_blocks
)
863 process_prepared_mapping(m
);
865 else if (io_overwrites_block(pool
, bio
)) {
866 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
868 h
->overwrite_mapping
= m
;
870 save_and_set_endio(bio
, &m
->saved_bi_end_io
, overwrite_endio
);
871 inc_all_io_entry(pool
, bio
);
872 remap_and_issue(tc
, bio
, data_block
);
875 struct dm_io_region to
;
877 to
.bdev
= tc
->pool_dev
->bdev
;
878 to
.sector
= data_block
* pool
->sectors_per_block
;
879 to
.count
= pool
->sectors_per_block
;
881 r
= dm_kcopyd_zero(pool
->copier
, 1, &to
, 0, copy_complete
, m
);
883 mempool_free(m
, pool
->mapping_pool
);
884 DMERR_LIMIT("dm_kcopyd_zero() failed");
885 cell_error(pool
, cell
);
891 * A non-zero return indicates read_only or fail_io mode.
892 * Many callers don't care about the return value.
894 static int commit(struct pool
*pool
)
898 if (get_pool_mode(pool
) != PM_WRITE
)
901 r
= dm_pool_commit_metadata(pool
->pmd
);
903 metadata_operation_failed(pool
, "dm_pool_commit_metadata", r
);
908 static void check_low_water_mark(struct pool
*pool
, dm_block_t free_blocks
)
912 if (free_blocks
<= pool
->low_water_blocks
&& !pool
->low_water_triggered
) {
913 DMWARN("%s: reached low water mark for data device: sending event.",
914 dm_device_name(pool
->pool_md
));
915 spin_lock_irqsave(&pool
->lock
, flags
);
916 pool
->low_water_triggered
= true;
917 spin_unlock_irqrestore(&pool
->lock
, flags
);
918 dm_table_event(pool
->ti
->table
);
922 static int alloc_data_block(struct thin_c
*tc
, dm_block_t
*result
)
925 dm_block_t free_blocks
;
926 struct pool
*pool
= tc
->pool
;
928 if (get_pool_mode(pool
) != PM_WRITE
)
931 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
933 metadata_operation_failed(pool
, "dm_pool_get_free_block_count", r
);
937 check_low_water_mark(pool
, free_blocks
);
941 * Try to commit to see if that will free up some
948 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
950 metadata_operation_failed(pool
, "dm_pool_get_free_block_count", r
);
955 out_of_data_space(pool
);
960 r
= dm_pool_alloc_data_block(pool
->pmd
, result
);
962 metadata_operation_failed(pool
, "dm_pool_alloc_data_block", r
);
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 handle_unserviceable_bio(struct pool
*pool
, struct bio
*bio
)
988 * When pool is read-only, no cell locking is needed because
989 * nothing is changing.
991 WARN_ON_ONCE(get_pool_mode(pool
) != PM_READ_ONLY
);
993 if (pool
->pf
.error_if_no_space
)
996 retry_on_resume(bio
);
999 static void retry_bios_on_resume(struct pool
*pool
, struct dm_bio_prison_cell
*cell
)
1002 struct bio_list bios
;
1004 bio_list_init(&bios
);
1005 cell_release(pool
, cell
, &bios
);
1007 while ((bio
= bio_list_pop(&bios
)))
1008 handle_unserviceable_bio(pool
, bio
);
1011 static void process_discard(struct thin_c
*tc
, struct bio
*bio
)
1014 unsigned long flags
;
1015 struct pool
*pool
= tc
->pool
;
1016 struct dm_bio_prison_cell
*cell
, *cell2
;
1017 struct dm_cell_key key
, key2
;
1018 dm_block_t block
= get_bio_block(tc
, bio
);
1019 struct dm_thin_lookup_result lookup_result
;
1020 struct dm_thin_new_mapping
*m
;
1022 build_virtual_key(tc
->td
, block
, &key
);
1023 if (bio_detain(tc
->pool
, &key
, bio
, &cell
))
1026 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1030 * Check nobody is fiddling with this pool block. This can
1031 * happen if someone's in the process of breaking sharing
1034 build_data_key(tc
->td
, lookup_result
.block
, &key2
);
1035 if (bio_detain(tc
->pool
, &key2
, bio
, &cell2
)) {
1036 cell_defer_no_holder(tc
, cell
);
1040 if (io_overlaps_block(pool
, bio
)) {
1042 * IO may still be going to the destination block. We must
1043 * quiesce before we can do the removal.
1045 m
= get_next_mapping(pool
);
1047 m
->pass_discard
= pool
->pf
.discard_passdown
;
1048 m
->definitely_not_shared
= !lookup_result
.shared
;
1049 m
->virt_block
= block
;
1050 m
->data_block
= lookup_result
.block
;
1055 if (!dm_deferred_set_add_work(pool
->all_io_ds
, &m
->list
)) {
1056 spin_lock_irqsave(&pool
->lock
, flags
);
1057 list_add_tail(&m
->list
, &pool
->prepared_discards
);
1058 spin_unlock_irqrestore(&pool
->lock
, flags
);
1062 inc_all_io_entry(pool
, bio
);
1063 cell_defer_no_holder(tc
, cell
);
1064 cell_defer_no_holder(tc
, cell2
);
1067 * The DM core makes sure that the discard doesn't span
1068 * a block boundary. So we submit the discard of a
1069 * partial block appropriately.
1071 if ((!lookup_result
.shared
) && pool
->pf
.discard_passdown
)
1072 remap_and_issue(tc
, bio
, lookup_result
.block
);
1080 * It isn't provisioned, just forget it.
1082 cell_defer_no_holder(tc
, cell
);
1087 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1089 cell_defer_no_holder(tc
, cell
);
1095 static void break_sharing(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1096 struct dm_cell_key
*key
,
1097 struct dm_thin_lookup_result
*lookup_result
,
1098 struct dm_bio_prison_cell
*cell
)
1101 dm_block_t data_block
;
1102 struct pool
*pool
= tc
->pool
;
1104 r
= alloc_data_block(tc
, &data_block
);
1107 schedule_internal_copy(tc
, block
, lookup_result
->block
,
1108 data_block
, cell
, bio
);
1112 retry_bios_on_resume(pool
, cell
);
1116 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1118 cell_error(pool
, cell
);
1123 static void process_shared_bio(struct thin_c
*tc
, struct bio
*bio
,
1125 struct dm_thin_lookup_result
*lookup_result
)
1127 struct dm_bio_prison_cell
*cell
;
1128 struct pool
*pool
= tc
->pool
;
1129 struct dm_cell_key key
;
1132 * If cell is already occupied, then sharing is already in the process
1133 * of being broken so we have nothing further to do here.
1135 build_data_key(tc
->td
, lookup_result
->block
, &key
);
1136 if (bio_detain(pool
, &key
, bio
, &cell
))
1139 if (bio_data_dir(bio
) == WRITE
&& bio
->bi_size
)
1140 break_sharing(tc
, bio
, block
, &key
, lookup_result
, cell
);
1142 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1144 h
->shared_read_entry
= dm_deferred_entry_inc(pool
->shared_read_ds
);
1145 inc_all_io_entry(pool
, bio
);
1146 cell_defer_no_holder(tc
, cell
);
1148 remap_and_issue(tc
, bio
, lookup_result
->block
);
1152 static void provision_block(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1153 struct dm_bio_prison_cell
*cell
)
1156 dm_block_t data_block
;
1157 struct pool
*pool
= tc
->pool
;
1160 * Remap empty bios (flushes) immediately, without provisioning.
1162 if (!bio
->bi_size
) {
1163 inc_all_io_entry(pool
, bio
);
1164 cell_defer_no_holder(tc
, cell
);
1166 remap_and_issue(tc
, bio
, 0);
1171 * Fill read bios with zeroes and complete them immediately.
1173 if (bio_data_dir(bio
) == READ
) {
1175 cell_defer_no_holder(tc
, cell
);
1180 r
= alloc_data_block(tc
, &data_block
);
1184 schedule_external_copy(tc
, block
, data_block
, cell
, bio
);
1186 schedule_zero(tc
, block
, data_block
, cell
, bio
);
1190 retry_bios_on_resume(pool
, cell
);
1194 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1196 cell_error(pool
, cell
);
1201 static void process_bio(struct thin_c
*tc
, struct bio
*bio
)
1204 struct pool
*pool
= tc
->pool
;
1205 dm_block_t block
= get_bio_block(tc
, bio
);
1206 struct dm_bio_prison_cell
*cell
;
1207 struct dm_cell_key key
;
1208 struct dm_thin_lookup_result lookup_result
;
1211 * If cell is already occupied, then the block is already
1212 * being provisioned so we have nothing further to do here.
1214 build_virtual_key(tc
->td
, block
, &key
);
1215 if (bio_detain(pool
, &key
, bio
, &cell
))
1218 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1221 if (lookup_result
.shared
) {
1222 process_shared_bio(tc
, bio
, block
, &lookup_result
);
1223 cell_defer_no_holder(tc
, cell
); /* FIXME: pass this cell into process_shared? */
1225 inc_all_io_entry(pool
, bio
);
1226 cell_defer_no_holder(tc
, cell
);
1228 remap_and_issue(tc
, bio
, lookup_result
.block
);
1233 if (bio_data_dir(bio
) == READ
&& tc
->origin_dev
) {
1234 inc_all_io_entry(pool
, bio
);
1235 cell_defer_no_holder(tc
, cell
);
1237 remap_to_origin_and_issue(tc
, bio
);
1239 provision_block(tc
, bio
, block
, cell
);
1243 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1245 cell_defer_no_holder(tc
, cell
);
1251 static void process_bio_read_only(struct thin_c
*tc
, struct bio
*bio
)
1254 int rw
= bio_data_dir(bio
);
1255 dm_block_t block
= get_bio_block(tc
, bio
);
1256 struct dm_thin_lookup_result lookup_result
;
1258 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1261 if (lookup_result
.shared
&& (rw
== WRITE
) && bio
->bi_size
)
1262 handle_unserviceable_bio(tc
->pool
, bio
);
1264 inc_all_io_entry(tc
->pool
, bio
);
1265 remap_and_issue(tc
, bio
, lookup_result
.block
);
1271 handle_unserviceable_bio(tc
->pool
, bio
);
1275 if (tc
->origin_dev
) {
1276 inc_all_io_entry(tc
->pool
, bio
);
1277 remap_to_origin_and_issue(tc
, bio
);
1286 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1293 static void process_bio_fail(struct thin_c
*tc
, struct bio
*bio
)
1299 * FIXME: should we also commit due to size of transaction, measured in
1302 static int need_commit_due_to_time(struct pool
*pool
)
1304 return jiffies
< pool
->last_commit_jiffies
||
1305 jiffies
> pool
->last_commit_jiffies
+ COMMIT_PERIOD
;
1308 static void process_deferred_bios(struct pool
*pool
)
1310 unsigned long flags
;
1312 struct bio_list bios
;
1314 bio_list_init(&bios
);
1316 spin_lock_irqsave(&pool
->lock
, flags
);
1317 bio_list_merge(&bios
, &pool
->deferred_bios
);
1318 bio_list_init(&pool
->deferred_bios
);
1319 spin_unlock_irqrestore(&pool
->lock
, flags
);
1321 while ((bio
= bio_list_pop(&bios
))) {
1322 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1323 struct thin_c
*tc
= h
->tc
;
1326 * If we've got no free new_mapping structs, and processing
1327 * this bio might require one, we pause until there are some
1328 * prepared mappings to process.
1330 if (ensure_next_mapping(pool
)) {
1331 spin_lock_irqsave(&pool
->lock
, flags
);
1332 bio_list_merge(&pool
->deferred_bios
, &bios
);
1333 spin_unlock_irqrestore(&pool
->lock
, flags
);
1338 if (bio
->bi_rw
& REQ_DISCARD
)
1339 pool
->process_discard(tc
, bio
);
1341 pool
->process_bio(tc
, bio
);
1345 * If there are any deferred flush bios, we must commit
1346 * the metadata before issuing them.
1348 bio_list_init(&bios
);
1349 spin_lock_irqsave(&pool
->lock
, flags
);
1350 bio_list_merge(&bios
, &pool
->deferred_flush_bios
);
1351 bio_list_init(&pool
->deferred_flush_bios
);
1352 spin_unlock_irqrestore(&pool
->lock
, flags
);
1354 if (bio_list_empty(&bios
) && !need_commit_due_to_time(pool
))
1358 while ((bio
= bio_list_pop(&bios
)))
1362 pool
->last_commit_jiffies
= jiffies
;
1364 while ((bio
= bio_list_pop(&bios
)))
1365 generic_make_request(bio
);
1368 static void do_worker(struct work_struct
*ws
)
1370 struct pool
*pool
= container_of(ws
, struct pool
, worker
);
1372 process_prepared(pool
, &pool
->prepared_mappings
, &pool
->process_prepared_mapping
);
1373 process_prepared(pool
, &pool
->prepared_discards
, &pool
->process_prepared_discard
);
1374 process_deferred_bios(pool
);
1378 * We want to commit periodically so that not too much
1379 * unwritten data builds up.
1381 static void do_waker(struct work_struct
*ws
)
1383 struct pool
*pool
= container_of(to_delayed_work(ws
), struct pool
, waker
);
1385 queue_delayed_work(pool
->wq
, &pool
->waker
, COMMIT_PERIOD
);
1388 /*----------------------------------------------------------------*/
1390 static enum pool_mode
get_pool_mode(struct pool
*pool
)
1392 return pool
->pf
.mode
;
1395 static void set_pool_mode(struct pool
*pool
, enum pool_mode mode
)
1399 pool
->pf
.mode
= mode
;
1403 DMERR("%s: switching pool to failure mode",
1404 dm_device_name(pool
->pool_md
));
1405 dm_pool_metadata_read_only(pool
->pmd
);
1406 pool
->process_bio
= process_bio_fail
;
1407 pool
->process_discard
= process_bio_fail
;
1408 pool
->process_prepared_mapping
= process_prepared_mapping_fail
;
1409 pool
->process_prepared_discard
= process_prepared_discard_fail
;
1413 DMERR("%s: switching pool to read-only mode",
1414 dm_device_name(pool
->pool_md
));
1415 r
= dm_pool_abort_metadata(pool
->pmd
);
1417 DMERR("%s: aborting transaction failed",
1418 dm_device_name(pool
->pool_md
));
1419 set_pool_mode(pool
, PM_FAIL
);
1421 dm_pool_metadata_read_only(pool
->pmd
);
1422 pool
->process_bio
= process_bio_read_only
;
1423 pool
->process_discard
= process_discard
;
1424 pool
->process_prepared_mapping
= process_prepared_mapping_fail
;
1425 pool
->process_prepared_discard
= process_prepared_discard_passdown
;
1430 dm_pool_metadata_read_write(pool
->pmd
);
1431 pool
->process_bio
= process_bio
;
1432 pool
->process_discard
= process_discard
;
1433 pool
->process_prepared_mapping
= process_prepared_mapping
;
1434 pool
->process_prepared_discard
= process_prepared_discard
;
1440 * Rather than calling set_pool_mode directly, use these which describe the
1441 * reason for mode degradation.
1443 static void out_of_data_space(struct pool
*pool
)
1445 DMERR_LIMIT("%s: no free data space available.",
1446 dm_device_name(pool
->pool_md
));
1447 set_pool_mode(pool
, PM_READ_ONLY
);
1450 static void metadata_operation_failed(struct pool
*pool
, const char *op
, int r
)
1452 dm_block_t free_blocks
;
1454 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
1455 dm_device_name(pool
->pool_md
), op
, r
);
1458 !dm_pool_get_free_metadata_block_count(pool
->pmd
, &free_blocks
) &&
1460 DMERR_LIMIT("%s: no free metadata space available.",
1461 dm_device_name(pool
->pool_md
));
1463 set_pool_mode(pool
, PM_READ_ONLY
);
1466 /*----------------------------------------------------------------*/
1469 * Mapping functions.
1473 * Called only while mapping a thin bio to hand it over to the workqueue.
1475 static void thin_defer_bio(struct thin_c
*tc
, struct bio
*bio
)
1477 unsigned long flags
;
1478 struct pool
*pool
= tc
->pool
;
1480 spin_lock_irqsave(&pool
->lock
, flags
);
1481 bio_list_add(&pool
->deferred_bios
, bio
);
1482 spin_unlock_irqrestore(&pool
->lock
, flags
);
1487 static void thin_hook_bio(struct thin_c
*tc
, struct bio
*bio
)
1489 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1492 h
->shared_read_entry
= NULL
;
1493 h
->all_io_entry
= NULL
;
1494 h
->overwrite_mapping
= NULL
;
1498 * Non-blocking function called from the thin target's map function.
1500 static int thin_bio_map(struct dm_target
*ti
, struct bio
*bio
)
1503 struct thin_c
*tc
= ti
->private;
1504 dm_block_t block
= get_bio_block(tc
, bio
);
1505 struct dm_thin_device
*td
= tc
->td
;
1506 struct dm_thin_lookup_result result
;
1507 struct dm_bio_prison_cell cell1
, cell2
;
1508 struct dm_bio_prison_cell
*cell_result
;
1509 struct dm_cell_key key
;
1511 thin_hook_bio(tc
, bio
);
1513 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
1515 return DM_MAPIO_SUBMITTED
;
1518 if (bio
->bi_rw
& (REQ_DISCARD
| REQ_FLUSH
| REQ_FUA
)) {
1519 thin_defer_bio(tc
, bio
);
1520 return DM_MAPIO_SUBMITTED
;
1523 r
= dm_thin_find_block(td
, block
, 0, &result
);
1526 * Note that we defer readahead too.
1530 if (unlikely(result
.shared
)) {
1532 * We have a race condition here between the
1533 * result.shared value returned by the lookup and
1534 * snapshot creation, which may cause new
1537 * To avoid this always quiesce the origin before
1538 * taking the snap. You want to do this anyway to
1539 * ensure a consistent application view
1542 * More distant ancestors are irrelevant. The
1543 * shared flag will be set in their case.
1545 thin_defer_bio(tc
, bio
);
1546 return DM_MAPIO_SUBMITTED
;
1549 build_virtual_key(tc
->td
, block
, &key
);
1550 if (dm_bio_detain(tc
->pool
->prison
, &key
, bio
, &cell1
, &cell_result
))
1551 return DM_MAPIO_SUBMITTED
;
1553 build_data_key(tc
->td
, result
.block
, &key
);
1554 if (dm_bio_detain(tc
->pool
->prison
, &key
, bio
, &cell2
, &cell_result
)) {
1555 cell_defer_no_holder_no_free(tc
, &cell1
);
1556 return DM_MAPIO_SUBMITTED
;
1559 inc_all_io_entry(tc
->pool
, bio
);
1560 cell_defer_no_holder_no_free(tc
, &cell2
);
1561 cell_defer_no_holder_no_free(tc
, &cell1
);
1563 remap(tc
, bio
, result
.block
);
1564 return DM_MAPIO_REMAPPED
;
1567 if (get_pool_mode(tc
->pool
) == PM_READ_ONLY
) {
1569 * This block isn't provisioned, and we have no way
1572 handle_unserviceable_bio(tc
->pool
, bio
);
1573 return DM_MAPIO_SUBMITTED
;
1579 * In future, the failed dm_thin_find_block above could
1580 * provide the hint to load the metadata into cache.
1582 thin_defer_bio(tc
, bio
);
1583 return DM_MAPIO_SUBMITTED
;
1587 * Must always call bio_io_error on failure.
1588 * dm_thin_find_block can fail with -EINVAL if the
1589 * pool is switched to fail-io mode.
1592 return DM_MAPIO_SUBMITTED
;
1596 static int pool_is_congested(struct dm_target_callbacks
*cb
, int bdi_bits
)
1599 unsigned long flags
;
1600 struct pool_c
*pt
= container_of(cb
, struct pool_c
, callbacks
);
1602 spin_lock_irqsave(&pt
->pool
->lock
, flags
);
1603 r
= !bio_list_empty(&pt
->pool
->retry_on_resume_list
);
1604 spin_unlock_irqrestore(&pt
->pool
->lock
, flags
);
1607 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1608 r
= bdi_congested(&q
->backing_dev_info
, bdi_bits
);
1614 static void __requeue_bios(struct pool
*pool
)
1616 bio_list_merge(&pool
->deferred_bios
, &pool
->retry_on_resume_list
);
1617 bio_list_init(&pool
->retry_on_resume_list
);
1620 /*----------------------------------------------------------------
1621 * Binding of control targets to a pool object
1622 *--------------------------------------------------------------*/
1623 static bool data_dev_supports_discard(struct pool_c
*pt
)
1625 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1627 return q
&& blk_queue_discard(q
);
1630 static bool is_factor(sector_t block_size
, uint32_t n
)
1632 return !sector_div(block_size
, n
);
1636 * If discard_passdown was enabled verify that the data device
1637 * supports discards. Disable discard_passdown if not.
1639 static void disable_passdown_if_not_supported(struct pool_c
*pt
)
1641 struct pool
*pool
= pt
->pool
;
1642 struct block_device
*data_bdev
= pt
->data_dev
->bdev
;
1643 struct queue_limits
*data_limits
= &bdev_get_queue(data_bdev
)->limits
;
1644 sector_t block_size
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
1645 const char *reason
= NULL
;
1646 char buf
[BDEVNAME_SIZE
];
1648 if (!pt
->adjusted_pf
.discard_passdown
)
1651 if (!data_dev_supports_discard(pt
))
1652 reason
= "discard unsupported";
1654 else if (data_limits
->max_discard_sectors
< pool
->sectors_per_block
)
1655 reason
= "max discard sectors smaller than a block";
1657 else if (data_limits
->discard_granularity
> block_size
)
1658 reason
= "discard granularity larger than a block";
1660 else if (!is_factor(block_size
, data_limits
->discard_granularity
))
1661 reason
= "discard granularity not a factor of block size";
1664 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev
, buf
), reason
);
1665 pt
->adjusted_pf
.discard_passdown
= false;
1669 static int bind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1671 struct pool_c
*pt
= ti
->private;
1674 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
1676 enum pool_mode old_mode
= pool
->pf
.mode
;
1677 enum pool_mode new_mode
= pt
->adjusted_pf
.mode
;
1680 * If we were in PM_FAIL mode, rollback of metadata failed. We're
1681 * not going to recover without a thin_repair. So we never let the
1682 * pool move out of the old mode. On the other hand a PM_READ_ONLY
1683 * may have been due to a lack of metadata or data space, and may
1684 * now work (ie. if the underlying devices have been resized).
1686 if (old_mode
== PM_FAIL
)
1687 new_mode
= old_mode
;
1690 pool
->low_water_blocks
= pt
->low_water_blocks
;
1691 pool
->pf
= pt
->adjusted_pf
;
1693 set_pool_mode(pool
, new_mode
);
1698 static void unbind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1704 /*----------------------------------------------------------------
1706 *--------------------------------------------------------------*/
1707 /* Initialize pool features. */
1708 static void pool_features_init(struct pool_features
*pf
)
1710 pf
->mode
= PM_WRITE
;
1711 pf
->zero_new_blocks
= true;
1712 pf
->discard_enabled
= true;
1713 pf
->discard_passdown
= true;
1714 pf
->error_if_no_space
= false;
1717 static void __pool_destroy(struct pool
*pool
)
1719 __pool_table_remove(pool
);
1721 if (dm_pool_metadata_close(pool
->pmd
) < 0)
1722 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1724 dm_bio_prison_destroy(pool
->prison
);
1725 dm_kcopyd_client_destroy(pool
->copier
);
1728 destroy_workqueue(pool
->wq
);
1730 if (pool
->next_mapping
)
1731 mempool_free(pool
->next_mapping
, pool
->mapping_pool
);
1732 mempool_destroy(pool
->mapping_pool
);
1733 dm_deferred_set_destroy(pool
->shared_read_ds
);
1734 dm_deferred_set_destroy(pool
->all_io_ds
);
1738 static struct kmem_cache
*_new_mapping_cache
;
1740 static struct pool
*pool_create(struct mapped_device
*pool_md
,
1741 struct block_device
*metadata_dev
,
1742 unsigned long block_size
,
1743 int read_only
, char **error
)
1748 struct dm_pool_metadata
*pmd
;
1749 bool format_device
= read_only
? false : true;
1751 pmd
= dm_pool_metadata_open(metadata_dev
, block_size
, format_device
);
1753 *error
= "Error creating metadata object";
1754 return (struct pool
*)pmd
;
1757 pool
= kmalloc(sizeof(*pool
), GFP_KERNEL
);
1759 *error
= "Error allocating memory for pool";
1760 err_p
= ERR_PTR(-ENOMEM
);
1765 pool
->sectors_per_block
= block_size
;
1766 if (block_size
& (block_size
- 1))
1767 pool
->sectors_per_block_shift
= -1;
1769 pool
->sectors_per_block_shift
= __ffs(block_size
);
1770 pool
->low_water_blocks
= 0;
1771 pool_features_init(&pool
->pf
);
1772 pool
->prison
= dm_bio_prison_create(PRISON_CELLS
);
1773 if (!pool
->prison
) {
1774 *error
= "Error creating pool's bio prison";
1775 err_p
= ERR_PTR(-ENOMEM
);
1779 pool
->copier
= dm_kcopyd_client_create(&dm_kcopyd_throttle
);
1780 if (IS_ERR(pool
->copier
)) {
1781 r
= PTR_ERR(pool
->copier
);
1782 *error
= "Error creating pool's kcopyd client";
1784 goto bad_kcopyd_client
;
1788 * Create singlethreaded workqueue that will service all devices
1789 * that use this metadata.
1791 pool
->wq
= alloc_ordered_workqueue("dm-" DM_MSG_PREFIX
, WQ_MEM_RECLAIM
);
1793 *error
= "Error creating pool's workqueue";
1794 err_p
= ERR_PTR(-ENOMEM
);
1798 INIT_WORK(&pool
->worker
, do_worker
);
1799 INIT_DELAYED_WORK(&pool
->waker
, do_waker
);
1800 spin_lock_init(&pool
->lock
);
1801 bio_list_init(&pool
->deferred_bios
);
1802 bio_list_init(&pool
->deferred_flush_bios
);
1803 INIT_LIST_HEAD(&pool
->prepared_mappings
);
1804 INIT_LIST_HEAD(&pool
->prepared_discards
);
1805 pool
->low_water_triggered
= false;
1806 bio_list_init(&pool
->retry_on_resume_list
);
1808 pool
->shared_read_ds
= dm_deferred_set_create();
1809 if (!pool
->shared_read_ds
) {
1810 *error
= "Error creating pool's shared read deferred set";
1811 err_p
= ERR_PTR(-ENOMEM
);
1812 goto bad_shared_read_ds
;
1815 pool
->all_io_ds
= dm_deferred_set_create();
1816 if (!pool
->all_io_ds
) {
1817 *error
= "Error creating pool's all io deferred set";
1818 err_p
= ERR_PTR(-ENOMEM
);
1822 pool
->next_mapping
= NULL
;
1823 pool
->mapping_pool
= mempool_create_slab_pool(MAPPING_POOL_SIZE
,
1824 _new_mapping_cache
);
1825 if (!pool
->mapping_pool
) {
1826 *error
= "Error creating pool's mapping mempool";
1827 err_p
= ERR_PTR(-ENOMEM
);
1828 goto bad_mapping_pool
;
1831 pool
->ref_count
= 1;
1832 pool
->last_commit_jiffies
= jiffies
;
1833 pool
->pool_md
= pool_md
;
1834 pool
->md_dev
= metadata_dev
;
1835 __pool_table_insert(pool
);
1840 dm_deferred_set_destroy(pool
->all_io_ds
);
1842 dm_deferred_set_destroy(pool
->shared_read_ds
);
1844 destroy_workqueue(pool
->wq
);
1846 dm_kcopyd_client_destroy(pool
->copier
);
1848 dm_bio_prison_destroy(pool
->prison
);
1852 if (dm_pool_metadata_close(pmd
))
1853 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1858 static void __pool_inc(struct pool
*pool
)
1860 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1864 static void __pool_dec(struct pool
*pool
)
1866 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1867 BUG_ON(!pool
->ref_count
);
1868 if (!--pool
->ref_count
)
1869 __pool_destroy(pool
);
1872 static struct pool
*__pool_find(struct mapped_device
*pool_md
,
1873 struct block_device
*metadata_dev
,
1874 unsigned long block_size
, int read_only
,
1875 char **error
, int *created
)
1877 struct pool
*pool
= __pool_table_lookup_metadata_dev(metadata_dev
);
1880 if (pool
->pool_md
!= pool_md
) {
1881 *error
= "metadata device already in use by a pool";
1882 return ERR_PTR(-EBUSY
);
1887 pool
= __pool_table_lookup(pool_md
);
1889 if (pool
->md_dev
!= metadata_dev
) {
1890 *error
= "different pool cannot replace a pool";
1891 return ERR_PTR(-EINVAL
);
1896 pool
= pool_create(pool_md
, metadata_dev
, block_size
, read_only
, error
);
1904 /*----------------------------------------------------------------
1905 * Pool target methods
1906 *--------------------------------------------------------------*/
1907 static void pool_dtr(struct dm_target
*ti
)
1909 struct pool_c
*pt
= ti
->private;
1911 mutex_lock(&dm_thin_pool_table
.mutex
);
1913 unbind_control_target(pt
->pool
, ti
);
1914 __pool_dec(pt
->pool
);
1915 dm_put_device(ti
, pt
->metadata_dev
);
1916 dm_put_device(ti
, pt
->data_dev
);
1919 mutex_unlock(&dm_thin_pool_table
.mutex
);
1922 static int parse_pool_features(struct dm_arg_set
*as
, struct pool_features
*pf
,
1923 struct dm_target
*ti
)
1927 const char *arg_name
;
1929 static struct dm_arg _args
[] = {
1930 {0, 3, "Invalid number of pool feature arguments"},
1934 * No feature arguments supplied.
1939 r
= dm_read_arg_group(_args
, as
, &argc
, &ti
->error
);
1943 while (argc
&& !r
) {
1944 arg_name
= dm_shift_arg(as
);
1947 if (!strcasecmp(arg_name
, "skip_block_zeroing"))
1948 pf
->zero_new_blocks
= false;
1950 else if (!strcasecmp(arg_name
, "ignore_discard"))
1951 pf
->discard_enabled
= false;
1953 else if (!strcasecmp(arg_name
, "no_discard_passdown"))
1954 pf
->discard_passdown
= false;
1956 else if (!strcasecmp(arg_name
, "read_only"))
1957 pf
->mode
= PM_READ_ONLY
;
1959 else if (!strcasecmp(arg_name
, "error_if_no_space"))
1960 pf
->error_if_no_space
= true;
1963 ti
->error
= "Unrecognised pool feature requested";
1972 static void metadata_low_callback(void *context
)
1974 struct pool
*pool
= context
;
1976 DMWARN("%s: reached low water mark for metadata device: sending event.",
1977 dm_device_name(pool
->pool_md
));
1979 dm_table_event(pool
->ti
->table
);
1982 static sector_t
get_metadata_dev_size(struct block_device
*bdev
)
1984 sector_t metadata_dev_size
= i_size_read(bdev
->bd_inode
) >> SECTOR_SHIFT
;
1985 char buffer
[BDEVNAME_SIZE
];
1987 if (metadata_dev_size
> THIN_METADATA_MAX_SECTORS_WARNING
) {
1988 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1989 bdevname(bdev
, buffer
), THIN_METADATA_MAX_SECTORS
);
1990 metadata_dev_size
= THIN_METADATA_MAX_SECTORS_WARNING
;
1993 return metadata_dev_size
;
1996 static dm_block_t
get_metadata_dev_size_in_blocks(struct block_device
*bdev
)
1998 sector_t metadata_dev_size
= get_metadata_dev_size(bdev
);
2000 sector_div(metadata_dev_size
, THIN_METADATA_BLOCK_SIZE
>> SECTOR_SHIFT
);
2002 return metadata_dev_size
;
2006 * When a metadata threshold is crossed a dm event is triggered, and
2007 * userland should respond by growing the metadata device. We could let
2008 * userland set the threshold, like we do with the data threshold, but I'm
2009 * not sure they know enough to do this well.
2011 static dm_block_t
calc_metadata_threshold(struct pool_c
*pt
)
2014 * 4M is ample for all ops with the possible exception of thin
2015 * device deletion which is harmless if it fails (just retry the
2016 * delete after you've grown the device).
2018 dm_block_t quarter
= get_metadata_dev_size_in_blocks(pt
->metadata_dev
->bdev
) / 4;
2019 return min((dm_block_t
)1024ULL /* 4M */, quarter
);
2023 * thin-pool <metadata dev> <data dev>
2024 * <data block size (sectors)>
2025 * <low water mark (blocks)>
2026 * [<#feature args> [<arg>]*]
2028 * Optional feature arguments are:
2029 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
2030 * ignore_discard: disable discard
2031 * no_discard_passdown: don't pass discards down to the data device
2032 * read_only: Don't allow any changes to be made to the pool metadata.
2033 * error_if_no_space: error IOs, instead of queueing, if no space.
2035 static int pool_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
2037 int r
, pool_created
= 0;
2040 struct pool_features pf
;
2041 struct dm_arg_set as
;
2042 struct dm_dev
*data_dev
;
2043 unsigned long block_size
;
2044 dm_block_t low_water_blocks
;
2045 struct dm_dev
*metadata_dev
;
2046 fmode_t metadata_mode
;
2049 * FIXME Remove validation from scope of lock.
2051 mutex_lock(&dm_thin_pool_table
.mutex
);
2054 ti
->error
= "Invalid argument count";
2063 * Set default pool features.
2065 pool_features_init(&pf
);
2067 dm_consume_args(&as
, 4);
2068 r
= parse_pool_features(&as
, &pf
, ti
);
2072 metadata_mode
= FMODE_READ
| ((pf
.mode
== PM_READ_ONLY
) ? 0 : FMODE_WRITE
);
2073 r
= dm_get_device(ti
, argv
[0], metadata_mode
, &metadata_dev
);
2075 ti
->error
= "Error opening metadata block device";
2080 * Run for the side-effect of possibly issuing a warning if the
2081 * device is too big.
2083 (void) get_metadata_dev_size(metadata_dev
->bdev
);
2085 r
= dm_get_device(ti
, argv
[1], FMODE_READ
| FMODE_WRITE
, &data_dev
);
2087 ti
->error
= "Error getting data device";
2091 if (kstrtoul(argv
[2], 10, &block_size
) || !block_size
||
2092 block_size
< DATA_DEV_BLOCK_SIZE_MIN_SECTORS
||
2093 block_size
> DATA_DEV_BLOCK_SIZE_MAX_SECTORS
||
2094 block_size
& (DATA_DEV_BLOCK_SIZE_MIN_SECTORS
- 1)) {
2095 ti
->error
= "Invalid block size";
2100 if (kstrtoull(argv
[3], 10, (unsigned long long *)&low_water_blocks
)) {
2101 ti
->error
= "Invalid low water mark";
2106 pt
= kzalloc(sizeof(*pt
), GFP_KERNEL
);
2112 pool
= __pool_find(dm_table_get_md(ti
->table
), metadata_dev
->bdev
,
2113 block_size
, pf
.mode
== PM_READ_ONLY
, &ti
->error
, &pool_created
);
2120 * 'pool_created' reflects whether this is the first table load.
2121 * Top level discard support is not allowed to be changed after
2122 * initial load. This would require a pool reload to trigger thin
2125 if (!pool_created
&& pf
.discard_enabled
!= pool
->pf
.discard_enabled
) {
2126 ti
->error
= "Discard support cannot be disabled once enabled";
2128 goto out_flags_changed
;
2133 pt
->metadata_dev
= metadata_dev
;
2134 pt
->data_dev
= data_dev
;
2135 pt
->low_water_blocks
= low_water_blocks
;
2136 pt
->adjusted_pf
= pt
->requested_pf
= pf
;
2137 ti
->num_flush_bios
= 1;
2140 * Only need to enable discards if the pool should pass
2141 * them down to the data device. The thin device's discard
2142 * processing will cause mappings to be removed from the btree.
2144 ti
->discard_zeroes_data_unsupported
= true;
2145 if (pf
.discard_enabled
&& pf
.discard_passdown
) {
2146 ti
->num_discard_bios
= 1;
2149 * Setting 'discards_supported' circumvents the normal
2150 * stacking of discard limits (this keeps the pool and
2151 * thin devices' discard limits consistent).
2153 ti
->discards_supported
= true;
2157 r
= dm_pool_register_metadata_threshold(pt
->pool
->pmd
,
2158 calc_metadata_threshold(pt
),
2159 metadata_low_callback
,
2164 pt
->callbacks
.congested_fn
= pool_is_congested
;
2165 dm_table_add_target_callbacks(ti
->table
, &pt
->callbacks
);
2167 mutex_unlock(&dm_thin_pool_table
.mutex
);
2176 dm_put_device(ti
, data_dev
);
2178 dm_put_device(ti
, metadata_dev
);
2180 mutex_unlock(&dm_thin_pool_table
.mutex
);
2185 static int pool_map(struct dm_target
*ti
, struct bio
*bio
)
2188 struct pool_c
*pt
= ti
->private;
2189 struct pool
*pool
= pt
->pool
;
2190 unsigned long flags
;
2193 * As this is a singleton target, ti->begin is always zero.
2195 spin_lock_irqsave(&pool
->lock
, flags
);
2196 bio
->bi_bdev
= pt
->data_dev
->bdev
;
2197 r
= DM_MAPIO_REMAPPED
;
2198 spin_unlock_irqrestore(&pool
->lock
, flags
);
2203 static int maybe_resize_data_dev(struct dm_target
*ti
, bool *need_commit
)
2206 struct pool_c
*pt
= ti
->private;
2207 struct pool
*pool
= pt
->pool
;
2208 sector_t data_size
= ti
->len
;
2209 dm_block_t sb_data_size
;
2211 *need_commit
= false;
2213 (void) sector_div(data_size
, pool
->sectors_per_block
);
2215 r
= dm_pool_get_data_dev_size(pool
->pmd
, &sb_data_size
);
2217 DMERR("%s: failed to retrieve data device size",
2218 dm_device_name(pool
->pool_md
));
2222 if (data_size
< sb_data_size
) {
2223 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
2224 dm_device_name(pool
->pool_md
),
2225 (unsigned long long)data_size
, sb_data_size
);
2228 } else if (data_size
> sb_data_size
) {
2230 DMINFO("%s: growing the data device from %llu to %llu blocks",
2231 dm_device_name(pool
->pool_md
),
2232 sb_data_size
, (unsigned long long)data_size
);
2233 r
= dm_pool_resize_data_dev(pool
->pmd
, data_size
);
2235 metadata_operation_failed(pool
, "dm_pool_resize_data_dev", r
);
2239 *need_commit
= true;
2245 static int maybe_resize_metadata_dev(struct dm_target
*ti
, bool *need_commit
)
2248 struct pool_c
*pt
= ti
->private;
2249 struct pool
*pool
= pt
->pool
;
2250 dm_block_t metadata_dev_size
, sb_metadata_dev_size
;
2252 *need_commit
= false;
2254 metadata_dev_size
= get_metadata_dev_size_in_blocks(pool
->md_dev
);
2256 r
= dm_pool_get_metadata_dev_size(pool
->pmd
, &sb_metadata_dev_size
);
2258 DMERR("%s: failed to retrieve metadata device size",
2259 dm_device_name(pool
->pool_md
));
2263 if (metadata_dev_size
< sb_metadata_dev_size
) {
2264 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
2265 dm_device_name(pool
->pool_md
),
2266 metadata_dev_size
, sb_metadata_dev_size
);
2269 } else if (metadata_dev_size
> sb_metadata_dev_size
) {
2270 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
2271 dm_device_name(pool
->pool_md
),
2272 sb_metadata_dev_size
, metadata_dev_size
);
2273 r
= dm_pool_resize_metadata_dev(pool
->pmd
, metadata_dev_size
);
2275 metadata_operation_failed(pool
, "dm_pool_resize_metadata_dev", r
);
2279 *need_commit
= true;
2286 * Retrieves the number of blocks of the data device from
2287 * the superblock and compares it to the actual device size,
2288 * thus resizing the data device in case it has grown.
2290 * This both copes with opening preallocated data devices in the ctr
2291 * being followed by a resume
2293 * calling the resume method individually after userspace has
2294 * grown the data device in reaction to a table event.
2296 static int pool_preresume(struct dm_target
*ti
)
2299 bool need_commit1
, need_commit2
;
2300 struct pool_c
*pt
= ti
->private;
2301 struct pool
*pool
= pt
->pool
;
2304 * Take control of the pool object.
2306 r
= bind_control_target(pool
, ti
);
2310 r
= maybe_resize_data_dev(ti
, &need_commit1
);
2314 r
= maybe_resize_metadata_dev(ti
, &need_commit2
);
2318 if (need_commit1
|| need_commit2
)
2319 (void) commit(pool
);
2324 static void pool_resume(struct dm_target
*ti
)
2326 struct pool_c
*pt
= ti
->private;
2327 struct pool
*pool
= pt
->pool
;
2328 unsigned long flags
;
2330 spin_lock_irqsave(&pool
->lock
, flags
);
2331 pool
->low_water_triggered
= false;
2332 __requeue_bios(pool
);
2333 spin_unlock_irqrestore(&pool
->lock
, flags
);
2335 do_waker(&pool
->waker
.work
);
2338 static void pool_postsuspend(struct dm_target
*ti
)
2340 struct pool_c
*pt
= ti
->private;
2341 struct pool
*pool
= pt
->pool
;
2343 cancel_delayed_work(&pool
->waker
);
2344 flush_workqueue(pool
->wq
);
2345 (void) commit(pool
);
2348 static int check_arg_count(unsigned argc
, unsigned args_required
)
2350 if (argc
!= args_required
) {
2351 DMWARN("Message received with %u arguments instead of %u.",
2352 argc
, args_required
);
2359 static int read_dev_id(char *arg
, dm_thin_id
*dev_id
, int warning
)
2361 if (!kstrtoull(arg
, 10, (unsigned long long *)dev_id
) &&
2362 *dev_id
<= MAX_DEV_ID
)
2366 DMWARN("Message received with invalid device id: %s", arg
);
2371 static int process_create_thin_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2376 r
= check_arg_count(argc
, 2);
2380 r
= read_dev_id(argv
[1], &dev_id
, 1);
2384 r
= dm_pool_create_thin(pool
->pmd
, dev_id
);
2386 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2394 static int process_create_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2397 dm_thin_id origin_dev_id
;
2400 r
= check_arg_count(argc
, 3);
2404 r
= read_dev_id(argv
[1], &dev_id
, 1);
2408 r
= read_dev_id(argv
[2], &origin_dev_id
, 1);
2412 r
= dm_pool_create_snap(pool
->pmd
, dev_id
, origin_dev_id
);
2414 DMWARN("Creation of new snapshot %s of device %s failed.",
2422 static int process_delete_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2427 r
= check_arg_count(argc
, 2);
2431 r
= read_dev_id(argv
[1], &dev_id
, 1);
2435 r
= dm_pool_delete_thin_device(pool
->pmd
, dev_id
);
2437 DMWARN("Deletion of thin device %s failed.", argv
[1]);
2442 static int process_set_transaction_id_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2444 dm_thin_id old_id
, new_id
;
2447 r
= check_arg_count(argc
, 3);
2451 if (kstrtoull(argv
[1], 10, (unsigned long long *)&old_id
)) {
2452 DMWARN("set_transaction_id message: Unrecognised id %s.", argv
[1]);
2456 if (kstrtoull(argv
[2], 10, (unsigned long long *)&new_id
)) {
2457 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv
[2]);
2461 r
= dm_pool_set_metadata_transaction_id(pool
->pmd
, old_id
, new_id
);
2463 DMWARN("Failed to change transaction id from %s to %s.",
2471 static int process_reserve_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2475 r
= check_arg_count(argc
, 1);
2479 (void) commit(pool
);
2481 r
= dm_pool_reserve_metadata_snap(pool
->pmd
);
2483 DMWARN("reserve_metadata_snap message failed.");
2488 static int process_release_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2492 r
= check_arg_count(argc
, 1);
2496 r
= dm_pool_release_metadata_snap(pool
->pmd
);
2498 DMWARN("release_metadata_snap message failed.");
2504 * Messages supported:
2505 * create_thin <dev_id>
2506 * create_snap <dev_id> <origin_id>
2508 * trim <dev_id> <new_size_in_sectors>
2509 * set_transaction_id <current_trans_id> <new_trans_id>
2510 * reserve_metadata_snap
2511 * release_metadata_snap
2513 static int pool_message(struct dm_target
*ti
, unsigned argc
, char **argv
)
2516 struct pool_c
*pt
= ti
->private;
2517 struct pool
*pool
= pt
->pool
;
2519 if (!strcasecmp(argv
[0], "create_thin"))
2520 r
= process_create_thin_mesg(argc
, argv
, pool
);
2522 else if (!strcasecmp(argv
[0], "create_snap"))
2523 r
= process_create_snap_mesg(argc
, argv
, pool
);
2525 else if (!strcasecmp(argv
[0], "delete"))
2526 r
= process_delete_mesg(argc
, argv
, pool
);
2528 else if (!strcasecmp(argv
[0], "set_transaction_id"))
2529 r
= process_set_transaction_id_mesg(argc
, argv
, pool
);
2531 else if (!strcasecmp(argv
[0], "reserve_metadata_snap"))
2532 r
= process_reserve_metadata_snap_mesg(argc
, argv
, pool
);
2534 else if (!strcasecmp(argv
[0], "release_metadata_snap"))
2535 r
= process_release_metadata_snap_mesg(argc
, argv
, pool
);
2538 DMWARN("Unrecognised thin pool target message received: %s", argv
[0]);
2541 (void) commit(pool
);
2546 static void emit_flags(struct pool_features
*pf
, char *result
,
2547 unsigned sz
, unsigned maxlen
)
2549 unsigned count
= !pf
->zero_new_blocks
+ !pf
->discard_enabled
+
2550 !pf
->discard_passdown
+ (pf
->mode
== PM_READ_ONLY
) +
2551 pf
->error_if_no_space
;
2552 DMEMIT("%u ", count
);
2554 if (!pf
->zero_new_blocks
)
2555 DMEMIT("skip_block_zeroing ");
2557 if (!pf
->discard_enabled
)
2558 DMEMIT("ignore_discard ");
2560 if (!pf
->discard_passdown
)
2561 DMEMIT("no_discard_passdown ");
2563 if (pf
->mode
== PM_READ_ONLY
)
2564 DMEMIT("read_only ");
2566 if (pf
->error_if_no_space
)
2567 DMEMIT("error_if_no_space ");
2572 * <transaction id> <used metadata sectors>/<total metadata sectors>
2573 * <used data sectors>/<total data sectors> <held metadata root>
2575 static void pool_status(struct dm_target
*ti
, status_type_t type
,
2576 unsigned status_flags
, char *result
, unsigned maxlen
)
2580 uint64_t transaction_id
;
2581 dm_block_t nr_free_blocks_data
;
2582 dm_block_t nr_free_blocks_metadata
;
2583 dm_block_t nr_blocks_data
;
2584 dm_block_t nr_blocks_metadata
;
2585 dm_block_t held_root
;
2586 char buf
[BDEVNAME_SIZE
];
2587 char buf2
[BDEVNAME_SIZE
];
2588 struct pool_c
*pt
= ti
->private;
2589 struct pool
*pool
= pt
->pool
;
2592 case STATUSTYPE_INFO
:
2593 if (get_pool_mode(pool
) == PM_FAIL
) {
2598 /* Commit to ensure statistics aren't out-of-date */
2599 if (!(status_flags
& DM_STATUS_NOFLUSH_FLAG
) && !dm_suspended(ti
))
2600 (void) commit(pool
);
2602 r
= dm_pool_get_metadata_transaction_id(pool
->pmd
, &transaction_id
);
2604 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
2605 dm_device_name(pool
->pool_md
), r
);
2609 r
= dm_pool_get_free_metadata_block_count(pool
->pmd
, &nr_free_blocks_metadata
);
2611 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
2612 dm_device_name(pool
->pool_md
), r
);
2616 r
= dm_pool_get_metadata_dev_size(pool
->pmd
, &nr_blocks_metadata
);
2618 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
2619 dm_device_name(pool
->pool_md
), r
);
2623 r
= dm_pool_get_free_block_count(pool
->pmd
, &nr_free_blocks_data
);
2625 DMERR("%s: dm_pool_get_free_block_count returned %d",
2626 dm_device_name(pool
->pool_md
), r
);
2630 r
= dm_pool_get_data_dev_size(pool
->pmd
, &nr_blocks_data
);
2632 DMERR("%s: dm_pool_get_data_dev_size returned %d",
2633 dm_device_name(pool
->pool_md
), r
);
2637 r
= dm_pool_get_metadata_snap(pool
->pmd
, &held_root
);
2639 DMERR("%s: dm_pool_get_metadata_snap returned %d",
2640 dm_device_name(pool
->pool_md
), r
);
2644 DMEMIT("%llu %llu/%llu %llu/%llu ",
2645 (unsigned long long)transaction_id
,
2646 (unsigned long long)(nr_blocks_metadata
- nr_free_blocks_metadata
),
2647 (unsigned long long)nr_blocks_metadata
,
2648 (unsigned long long)(nr_blocks_data
- nr_free_blocks_data
),
2649 (unsigned long long)nr_blocks_data
);
2652 DMEMIT("%llu ", held_root
);
2656 if (pool
->pf
.mode
== PM_READ_ONLY
)
2661 if (!pool
->pf
.discard_enabled
)
2662 DMEMIT("ignore_discard ");
2663 else if (pool
->pf
.discard_passdown
)
2664 DMEMIT("discard_passdown ");
2666 DMEMIT("no_discard_passdown ");
2668 if (pool
->pf
.error_if_no_space
)
2669 DMEMIT("error_if_no_space ");
2671 DMEMIT("queue_if_no_space ");
2675 case STATUSTYPE_TABLE
:
2676 DMEMIT("%s %s %lu %llu ",
2677 format_dev_t(buf
, pt
->metadata_dev
->bdev
->bd_dev
),
2678 format_dev_t(buf2
, pt
->data_dev
->bdev
->bd_dev
),
2679 (unsigned long)pool
->sectors_per_block
,
2680 (unsigned long long)pt
->low_water_blocks
);
2681 emit_flags(&pt
->requested_pf
, result
, sz
, maxlen
);
2690 static int pool_iterate_devices(struct dm_target
*ti
,
2691 iterate_devices_callout_fn fn
, void *data
)
2693 struct pool_c
*pt
= ti
->private;
2695 return fn(ti
, pt
->data_dev
, 0, ti
->len
, data
);
2698 static int pool_merge(struct dm_target
*ti
, struct bvec_merge_data
*bvm
,
2699 struct bio_vec
*biovec
, int max_size
)
2701 struct pool_c
*pt
= ti
->private;
2702 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
2704 if (!q
->merge_bvec_fn
)
2707 bvm
->bi_bdev
= pt
->data_dev
->bdev
;
2709 return min(max_size
, q
->merge_bvec_fn(q
, bvm
, biovec
));
2712 static void set_discard_limits(struct pool_c
*pt
, struct queue_limits
*limits
)
2714 struct pool
*pool
= pt
->pool
;
2715 struct queue_limits
*data_limits
;
2717 limits
->max_discard_sectors
= pool
->sectors_per_block
;
2720 * discard_granularity is just a hint, and not enforced.
2722 if (pt
->adjusted_pf
.discard_passdown
) {
2723 data_limits
= &bdev_get_queue(pt
->data_dev
->bdev
)->limits
;
2724 limits
->discard_granularity
= data_limits
->discard_granularity
;
2726 limits
->discard_granularity
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
2729 static void pool_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
2731 struct pool_c
*pt
= ti
->private;
2732 struct pool
*pool
= pt
->pool
;
2733 uint64_t io_opt_sectors
= limits
->io_opt
>> SECTOR_SHIFT
;
2736 * If the system-determined stacked limits are compatible with the
2737 * pool's blocksize (io_opt is a factor) do not override them.
2739 if (io_opt_sectors
< pool
->sectors_per_block
||
2740 do_div(io_opt_sectors
, pool
->sectors_per_block
)) {
2741 blk_limits_io_min(limits
, 0);
2742 blk_limits_io_opt(limits
, pool
->sectors_per_block
<< SECTOR_SHIFT
);
2746 * pt->adjusted_pf is a staging area for the actual features to use.
2747 * They get transferred to the live pool in bind_control_target()
2748 * called from pool_preresume().
2750 if (!pt
->adjusted_pf
.discard_enabled
) {
2752 * Must explicitly disallow stacking discard limits otherwise the
2753 * block layer will stack them if pool's data device has support.
2754 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
2755 * user to see that, so make sure to set all discard limits to 0.
2757 limits
->discard_granularity
= 0;
2761 disable_passdown_if_not_supported(pt
);
2763 set_discard_limits(pt
, limits
);
2766 static struct target_type pool_target
= {
2767 .name
= "thin-pool",
2768 .features
= DM_TARGET_SINGLETON
| DM_TARGET_ALWAYS_WRITEABLE
|
2769 DM_TARGET_IMMUTABLE
,
2770 .version
= {1, 10, 0},
2771 .module
= THIS_MODULE
,
2775 .postsuspend
= pool_postsuspend
,
2776 .preresume
= pool_preresume
,
2777 .resume
= pool_resume
,
2778 .message
= pool_message
,
2779 .status
= pool_status
,
2780 .merge
= pool_merge
,
2781 .iterate_devices
= pool_iterate_devices
,
2782 .io_hints
= pool_io_hints
,
2785 /*----------------------------------------------------------------
2786 * Thin target methods
2787 *--------------------------------------------------------------*/
2788 static void thin_dtr(struct dm_target
*ti
)
2790 struct thin_c
*tc
= ti
->private;
2792 mutex_lock(&dm_thin_pool_table
.mutex
);
2794 __pool_dec(tc
->pool
);
2795 dm_pool_close_thin_device(tc
->td
);
2796 dm_put_device(ti
, tc
->pool_dev
);
2798 dm_put_device(ti
, tc
->origin_dev
);
2801 mutex_unlock(&dm_thin_pool_table
.mutex
);
2805 * Thin target parameters:
2807 * <pool_dev> <dev_id> [origin_dev]
2809 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2810 * dev_id: the internal device identifier
2811 * origin_dev: a device external to the pool that should act as the origin
2813 * If the pool device has discards disabled, they get disabled for the thin
2816 static int thin_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
2820 struct dm_dev
*pool_dev
, *origin_dev
;
2821 struct mapped_device
*pool_md
;
2823 mutex_lock(&dm_thin_pool_table
.mutex
);
2825 if (argc
!= 2 && argc
!= 3) {
2826 ti
->error
= "Invalid argument count";
2831 tc
= ti
->private = kzalloc(sizeof(*tc
), GFP_KERNEL
);
2833 ti
->error
= "Out of memory";
2839 r
= dm_get_device(ti
, argv
[2], FMODE_READ
, &origin_dev
);
2841 ti
->error
= "Error opening origin device";
2842 goto bad_origin_dev
;
2844 tc
->origin_dev
= origin_dev
;
2847 r
= dm_get_device(ti
, argv
[0], dm_table_get_mode(ti
->table
), &pool_dev
);
2849 ti
->error
= "Error opening pool device";
2852 tc
->pool_dev
= pool_dev
;
2854 if (read_dev_id(argv
[1], (unsigned long long *)&tc
->dev_id
, 0)) {
2855 ti
->error
= "Invalid device id";
2860 pool_md
= dm_get_md(tc
->pool_dev
->bdev
->bd_dev
);
2862 ti
->error
= "Couldn't get pool mapped device";
2867 tc
->pool
= __pool_table_lookup(pool_md
);
2869 ti
->error
= "Couldn't find pool object";
2871 goto bad_pool_lookup
;
2873 __pool_inc(tc
->pool
);
2875 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
2876 ti
->error
= "Couldn't open thin device, Pool is in fail mode";
2880 r
= dm_pool_open_thin_device(tc
->pool
->pmd
, tc
->dev_id
, &tc
->td
);
2882 ti
->error
= "Couldn't open thin internal device";
2886 r
= dm_set_target_max_io_len(ti
, tc
->pool
->sectors_per_block
);
2890 ti
->num_flush_bios
= 1;
2891 ti
->flush_supported
= true;
2892 ti
->per_bio_data_size
= sizeof(struct dm_thin_endio_hook
);
2894 /* In case the pool supports discards, pass them on. */
2895 ti
->discard_zeroes_data_unsupported
= true;
2896 if (tc
->pool
->pf
.discard_enabled
) {
2897 ti
->discards_supported
= true;
2898 ti
->num_discard_bios
= 1;
2899 /* Discard bios must be split on a block boundary */
2900 ti
->split_discard_bios
= true;
2905 mutex_unlock(&dm_thin_pool_table
.mutex
);
2910 __pool_dec(tc
->pool
);
2914 dm_put_device(ti
, tc
->pool_dev
);
2917 dm_put_device(ti
, tc
->origin_dev
);
2921 mutex_unlock(&dm_thin_pool_table
.mutex
);
2926 static int thin_map(struct dm_target
*ti
, struct bio
*bio
)
2928 bio
->bi_sector
= dm_target_offset(ti
, bio
->bi_sector
);
2930 return thin_bio_map(ti
, bio
);
2933 static int thin_endio(struct dm_target
*ti
, struct bio
*bio
, int err
)
2935 unsigned long flags
;
2936 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
2937 struct list_head work
;
2938 struct dm_thin_new_mapping
*m
, *tmp
;
2939 struct pool
*pool
= h
->tc
->pool
;
2941 if (h
->shared_read_entry
) {
2942 INIT_LIST_HEAD(&work
);
2943 dm_deferred_entry_dec(h
->shared_read_entry
, &work
);
2945 spin_lock_irqsave(&pool
->lock
, flags
);
2946 list_for_each_entry_safe(m
, tmp
, &work
, list
) {
2949 __maybe_add_mapping(m
);
2951 spin_unlock_irqrestore(&pool
->lock
, flags
);
2954 if (h
->all_io_entry
) {
2955 INIT_LIST_HEAD(&work
);
2956 dm_deferred_entry_dec(h
->all_io_entry
, &work
);
2957 if (!list_empty(&work
)) {
2958 spin_lock_irqsave(&pool
->lock
, flags
);
2959 list_for_each_entry_safe(m
, tmp
, &work
, list
)
2960 list_add_tail(&m
->list
, &pool
->prepared_discards
);
2961 spin_unlock_irqrestore(&pool
->lock
, flags
);
2969 static void thin_postsuspend(struct dm_target
*ti
)
2971 if (dm_noflush_suspending(ti
))
2972 requeue_io((struct thin_c
*)ti
->private);
2976 * <nr mapped sectors> <highest mapped sector>
2978 static void thin_status(struct dm_target
*ti
, status_type_t type
,
2979 unsigned status_flags
, char *result
, unsigned maxlen
)
2983 dm_block_t mapped
, highest
;
2984 char buf
[BDEVNAME_SIZE
];
2985 struct thin_c
*tc
= ti
->private;
2987 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
2996 case STATUSTYPE_INFO
:
2997 r
= dm_thin_get_mapped_count(tc
->td
, &mapped
);
2999 DMERR("dm_thin_get_mapped_count returned %d", r
);
3003 r
= dm_thin_get_highest_mapped_block(tc
->td
, &highest
);
3005 DMERR("dm_thin_get_highest_mapped_block returned %d", r
);
3009 DMEMIT("%llu ", mapped
* tc
->pool
->sectors_per_block
);
3011 DMEMIT("%llu", ((highest
+ 1) *
3012 tc
->pool
->sectors_per_block
) - 1);
3017 case STATUSTYPE_TABLE
:
3019 format_dev_t(buf
, tc
->pool_dev
->bdev
->bd_dev
),
3020 (unsigned long) tc
->dev_id
);
3022 DMEMIT(" %s", format_dev_t(buf
, tc
->origin_dev
->bdev
->bd_dev
));
3033 static int thin_iterate_devices(struct dm_target
*ti
,
3034 iterate_devices_callout_fn fn
, void *data
)
3037 struct thin_c
*tc
= ti
->private;
3038 struct pool
*pool
= tc
->pool
;
3041 * We can't call dm_pool_get_data_dev_size() since that blocks. So
3042 * we follow a more convoluted path through to the pool's target.
3045 return 0; /* nothing is bound */
3047 blocks
= pool
->ti
->len
;
3048 (void) sector_div(blocks
, pool
->sectors_per_block
);
3050 return fn(ti
, tc
->pool_dev
, 0, pool
->sectors_per_block
* blocks
, data
);
3055 static struct target_type thin_target
= {
3057 .version
= {1, 10, 0},
3058 .module
= THIS_MODULE
,
3062 .end_io
= thin_endio
,
3063 .postsuspend
= thin_postsuspend
,
3064 .status
= thin_status
,
3065 .iterate_devices
= thin_iterate_devices
,
3068 /*----------------------------------------------------------------*/
3070 static int __init
dm_thin_init(void)
3076 r
= dm_register_target(&thin_target
);
3080 r
= dm_register_target(&pool_target
);
3082 goto bad_pool_target
;
3086 _new_mapping_cache
= KMEM_CACHE(dm_thin_new_mapping
, 0);
3087 if (!_new_mapping_cache
)
3088 goto bad_new_mapping_cache
;
3092 bad_new_mapping_cache
:
3093 dm_unregister_target(&pool_target
);
3095 dm_unregister_target(&thin_target
);
3100 static void dm_thin_exit(void)
3102 dm_unregister_target(&thin_target
);
3103 dm_unregister_target(&pool_target
);
3105 kmem_cache_destroy(_new_mapping_cache
);
3108 module_init(dm_thin_init
);
3109 module_exit(dm_thin_exit
);
3111 MODULE_DESCRIPTION(DM_NAME
" thin provisioning target");
3112 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3113 MODULE_LICENSE("GPL");