2 * Copyright (C) 2011-2012 Red Hat UK.
4 * This file is released under the GPL.
7 #include "dm-thin-metadata.h"
8 #include "dm-bio-prison.h"
11 #include <linux/device-mapper.h>
12 #include <linux/dm-io.h>
13 #include <linux/dm-kcopyd.h>
14 #include <linux/list.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
19 #define DM_MSG_PREFIX "thin"
24 #define ENDIO_HOOK_POOL_SIZE 1024
25 #define MAPPING_POOL_SIZE 1024
26 #define PRISON_CELLS 1024
27 #define COMMIT_PERIOD HZ
29 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle
,
30 "A percentage of time allocated for copy on write");
33 * The block size of the device holding pool data must be
34 * between 64KB and 1GB.
36 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
37 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
40 * Device id is restricted to 24 bits.
42 #define MAX_DEV_ID ((1 << 24) - 1)
45 * How do we handle breaking sharing of data blocks?
46 * =================================================
48 * We use a standard copy-on-write btree to store the mappings for the
49 * devices (note I'm talking about copy-on-write of the metadata here, not
50 * the data). When you take an internal snapshot you clone the root node
51 * of the origin btree. After this there is no concept of an origin or a
52 * snapshot. They are just two device trees that happen to point to the
55 * When we get a write in we decide if it's to a shared data block using
56 * some timestamp magic. If it is, we have to break sharing.
58 * Let's say we write to a shared block in what was the origin. The
61 * i) plug io further to this physical block. (see bio_prison code).
63 * ii) quiesce any read io to that shared data block. Obviously
64 * including all devices that share this block. (see dm_deferred_set code)
66 * iii) copy the data block to a newly allocate block. This step can be
67 * missed out if the io covers the block. (schedule_copy).
69 * iv) insert the new mapping into the origin's btree
70 * (process_prepared_mapping). This act of inserting breaks some
71 * sharing of btree nodes between the two devices. Breaking sharing only
72 * effects the btree of that specific device. Btrees for the other
73 * devices that share the block never change. The btree for the origin
74 * device as it was after the last commit is untouched, ie. we're using
75 * persistent data structures in the functional programming sense.
77 * v) unplug io to this physical block, including the io that triggered
78 * the breaking of sharing.
80 * Steps (ii) and (iii) occur in parallel.
82 * The metadata _doesn't_ need to be committed before the io continues. We
83 * get away with this because the io is always written to a _new_ block.
84 * If there's a crash, then:
86 * - The origin mapping will point to the old origin block (the shared
87 * one). This will contain the data as it was before the io that triggered
88 * the breaking of sharing came in.
90 * - The snap mapping still points to the old block. As it would after
93 * The downside of this scheme is the timestamp magic isn't perfect, and
94 * will continue to think that data block in the snapshot device is shared
95 * even after the write to the origin has broken sharing. I suspect data
96 * blocks will typically be shared by many different devices, so we're
97 * breaking sharing n + 1 times, rather than n, where n is the number of
98 * devices that reference this data block. At the moment I think the
99 * benefits far, far outweigh the disadvantages.
102 /*----------------------------------------------------------------*/
107 static void build_data_key(struct dm_thin_device
*td
,
108 dm_block_t b
, struct dm_cell_key
*key
)
111 key
->dev
= dm_thin_dev_id(td
);
115 static void build_virtual_key(struct dm_thin_device
*td
, dm_block_t b
,
116 struct dm_cell_key
*key
)
119 key
->dev
= dm_thin_dev_id(td
);
123 /*----------------------------------------------------------------*/
126 * A pool device ties together a metadata device and a data device. It
127 * also provides the interface for creating and destroying internal
130 struct dm_thin_new_mapping
;
133 * The pool runs in 3 modes. Ordered in degraded order for comparisons.
136 PM_WRITE
, /* metadata may be changed */
137 PM_READ_ONLY
, /* metadata may not be changed */
138 PM_FAIL
, /* all I/O fails */
141 struct pool_features
{
144 bool zero_new_blocks
:1;
145 bool discard_enabled
:1;
146 bool discard_passdown
:1;
150 typedef void (*process_bio_fn
)(struct thin_c
*tc
, struct bio
*bio
);
151 typedef void (*process_mapping_fn
)(struct dm_thin_new_mapping
*m
);
154 struct list_head list
;
155 struct dm_target
*ti
; /* Only set if a pool target is bound */
157 struct mapped_device
*pool_md
;
158 struct block_device
*md_dev
;
159 struct dm_pool_metadata
*pmd
;
161 dm_block_t low_water_blocks
;
162 uint32_t sectors_per_block
;
163 int sectors_per_block_shift
;
165 struct pool_features pf
;
166 unsigned low_water_triggered
:1; /* A dm event has been sent */
167 unsigned no_free_space
:1; /* A -ENOSPC warning has been issued */
169 struct dm_bio_prison
*prison
;
170 struct dm_kcopyd_client
*copier
;
172 struct workqueue_struct
*wq
;
173 struct work_struct worker
;
174 struct delayed_work waker
;
176 unsigned long last_commit_jiffies
;
180 struct bio_list deferred_bios
;
181 struct bio_list deferred_flush_bios
;
182 struct list_head prepared_mappings
;
183 struct list_head prepared_discards
;
185 struct bio_list retry_on_resume_list
;
187 struct dm_deferred_set
*shared_read_ds
;
188 struct dm_deferred_set
*all_io_ds
;
190 struct dm_thin_new_mapping
*next_mapping
;
191 mempool_t
*mapping_pool
;
193 process_bio_fn process_bio
;
194 process_bio_fn process_discard
;
196 process_mapping_fn process_prepared_mapping
;
197 process_mapping_fn process_prepared_discard
;
200 static enum pool_mode
get_pool_mode(struct pool
*pool
);
201 static void set_pool_mode(struct pool
*pool
, enum pool_mode mode
);
204 * Target context for a pool.
207 struct dm_target
*ti
;
209 struct dm_dev
*data_dev
;
210 struct dm_dev
*metadata_dev
;
211 struct dm_target_callbacks callbacks
;
213 dm_block_t low_water_blocks
;
214 struct pool_features requested_pf
; /* Features requested during table load */
215 struct pool_features adjusted_pf
; /* Features used after adjusting for constituent devices */
219 * Target context for a thin.
222 struct dm_dev
*pool_dev
;
223 struct dm_dev
*origin_dev
;
227 struct dm_thin_device
*td
;
230 /*----------------------------------------------------------------*/
233 * wake_worker() is used when new work is queued and when pool_resume is
234 * ready to continue deferred IO processing.
236 static void wake_worker(struct pool
*pool
)
238 queue_work(pool
->wq
, &pool
->worker
);
241 /*----------------------------------------------------------------*/
243 static int bio_detain(struct pool
*pool
, struct dm_cell_key
*key
, struct bio
*bio
,
244 struct dm_bio_prison_cell
**cell_result
)
247 struct dm_bio_prison_cell
*cell_prealloc
;
250 * Allocate a cell from the prison's mempool.
251 * This might block but it can't fail.
253 cell_prealloc
= dm_bio_prison_alloc_cell(pool
->prison
, GFP_NOIO
);
255 r
= dm_bio_detain(pool
->prison
, key
, bio
, cell_prealloc
, cell_result
);
258 * We reused an old cell; we can get rid of
261 dm_bio_prison_free_cell(pool
->prison
, cell_prealloc
);
266 static void cell_release(struct pool
*pool
,
267 struct dm_bio_prison_cell
*cell
,
268 struct bio_list
*bios
)
270 dm_cell_release(pool
->prison
, cell
, bios
);
271 dm_bio_prison_free_cell(pool
->prison
, cell
);
274 static void cell_release_no_holder(struct pool
*pool
,
275 struct dm_bio_prison_cell
*cell
,
276 struct bio_list
*bios
)
278 dm_cell_release_no_holder(pool
->prison
, cell
, bios
);
279 dm_bio_prison_free_cell(pool
->prison
, cell
);
282 static void cell_defer_no_holder_no_free(struct thin_c
*tc
,
283 struct dm_bio_prison_cell
*cell
)
285 struct pool
*pool
= tc
->pool
;
288 spin_lock_irqsave(&pool
->lock
, flags
);
289 dm_cell_release_no_holder(pool
->prison
, cell
, &pool
->deferred_bios
);
290 spin_unlock_irqrestore(&pool
->lock
, flags
);
295 static void cell_error(struct pool
*pool
,
296 struct dm_bio_prison_cell
*cell
)
298 dm_cell_error(pool
->prison
, cell
);
299 dm_bio_prison_free_cell(pool
->prison
, cell
);
302 /*----------------------------------------------------------------*/
305 * A global list of pools that uses a struct mapped_device as a key.
307 static struct dm_thin_pool_table
{
309 struct list_head pools
;
310 } dm_thin_pool_table
;
312 static void pool_table_init(void)
314 mutex_init(&dm_thin_pool_table
.mutex
);
315 INIT_LIST_HEAD(&dm_thin_pool_table
.pools
);
318 static void __pool_table_insert(struct pool
*pool
)
320 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
321 list_add(&pool
->list
, &dm_thin_pool_table
.pools
);
324 static void __pool_table_remove(struct pool
*pool
)
326 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
327 list_del(&pool
->list
);
330 static struct pool
*__pool_table_lookup(struct mapped_device
*md
)
332 struct pool
*pool
= NULL
, *tmp
;
334 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
336 list_for_each_entry(tmp
, &dm_thin_pool_table
.pools
, list
) {
337 if (tmp
->pool_md
== md
) {
346 static struct pool
*__pool_table_lookup_metadata_dev(struct block_device
*md_dev
)
348 struct pool
*pool
= NULL
, *tmp
;
350 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
352 list_for_each_entry(tmp
, &dm_thin_pool_table
.pools
, list
) {
353 if (tmp
->md_dev
== md_dev
) {
362 /*----------------------------------------------------------------*/
364 struct dm_thin_endio_hook
{
366 struct dm_deferred_entry
*shared_read_entry
;
367 struct dm_deferred_entry
*all_io_entry
;
368 struct dm_thin_new_mapping
*overwrite_mapping
;
371 static void __requeue_bio_list(struct thin_c
*tc
, struct bio_list
*master
)
374 struct bio_list bios
;
376 bio_list_init(&bios
);
377 bio_list_merge(&bios
, master
);
378 bio_list_init(master
);
380 while ((bio
= bio_list_pop(&bios
))) {
381 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
384 bio_endio(bio
, DM_ENDIO_REQUEUE
);
386 bio_list_add(master
, bio
);
390 static void requeue_io(struct thin_c
*tc
)
392 struct pool
*pool
= tc
->pool
;
395 spin_lock_irqsave(&pool
->lock
, flags
);
396 __requeue_bio_list(tc
, &pool
->deferred_bios
);
397 __requeue_bio_list(tc
, &pool
->retry_on_resume_list
);
398 spin_unlock_irqrestore(&pool
->lock
, flags
);
402 * This section of code contains the logic for processing a thin device's IO.
403 * Much of the code depends on pool object resources (lists, workqueues, etc)
404 * but most is exclusively called from the thin target rather than the thin-pool
408 static bool block_size_is_power_of_two(struct pool
*pool
)
410 return pool
->sectors_per_block_shift
>= 0;
413 static dm_block_t
get_bio_block(struct thin_c
*tc
, struct bio
*bio
)
415 struct pool
*pool
= tc
->pool
;
416 sector_t block_nr
= bio
->bi_sector
;
418 if (block_size_is_power_of_two(pool
))
419 block_nr
>>= pool
->sectors_per_block_shift
;
421 (void) sector_div(block_nr
, pool
->sectors_per_block
);
426 static void remap(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
)
428 struct pool
*pool
= tc
->pool
;
429 sector_t bi_sector
= bio
->bi_sector
;
431 bio
->bi_bdev
= tc
->pool_dev
->bdev
;
432 if (block_size_is_power_of_two(pool
))
433 bio
->bi_sector
= (block
<< pool
->sectors_per_block_shift
) |
434 (bi_sector
& (pool
->sectors_per_block
- 1));
436 bio
->bi_sector
= (block
* pool
->sectors_per_block
) +
437 sector_div(bi_sector
, pool
->sectors_per_block
);
440 static void remap_to_origin(struct thin_c
*tc
, struct bio
*bio
)
442 bio
->bi_bdev
= tc
->origin_dev
->bdev
;
445 static int bio_triggers_commit(struct thin_c
*tc
, struct bio
*bio
)
447 return (bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
)) &&
448 dm_thin_changed_this_transaction(tc
->td
);
451 static void inc_all_io_entry(struct pool
*pool
, struct bio
*bio
)
453 struct dm_thin_endio_hook
*h
;
455 if (bio
->bi_rw
& REQ_DISCARD
)
458 h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
459 h
->all_io_entry
= dm_deferred_entry_inc(pool
->all_io_ds
);
462 static void issue(struct thin_c
*tc
, struct bio
*bio
)
464 struct pool
*pool
= tc
->pool
;
467 if (!bio_triggers_commit(tc
, bio
)) {
468 generic_make_request(bio
);
473 * Complete bio with an error if earlier I/O caused changes to
474 * the metadata that can't be committed e.g, due to I/O errors
475 * on the metadata device.
477 if (dm_thin_aborted_changes(tc
->td
)) {
483 * Batch together any bios that trigger commits and then issue a
484 * single commit for them in process_deferred_bios().
486 spin_lock_irqsave(&pool
->lock
, flags
);
487 bio_list_add(&pool
->deferred_flush_bios
, bio
);
488 spin_unlock_irqrestore(&pool
->lock
, flags
);
491 static void remap_to_origin_and_issue(struct thin_c
*tc
, struct bio
*bio
)
493 remap_to_origin(tc
, bio
);
497 static void remap_and_issue(struct thin_c
*tc
, struct bio
*bio
,
500 remap(tc
, bio
, block
);
504 /*----------------------------------------------------------------*/
507 * Bio endio functions.
509 struct dm_thin_new_mapping
{
510 struct list_head list
;
514 unsigned pass_discard
:1;
517 dm_block_t virt_block
;
518 dm_block_t data_block
;
519 struct dm_bio_prison_cell
*cell
, *cell2
;
523 * If the bio covers the whole area of a block then we can avoid
524 * zeroing or copying. Instead this bio is hooked. The bio will
525 * still be in the cell, so care has to be taken to avoid issuing
529 bio_end_io_t
*saved_bi_end_io
;
532 static void __maybe_add_mapping(struct dm_thin_new_mapping
*m
)
534 struct pool
*pool
= m
->tc
->pool
;
536 if (m
->quiesced
&& m
->prepared
) {
537 list_add(&m
->list
, &pool
->prepared_mappings
);
542 static void copy_complete(int read_err
, unsigned long write_err
, void *context
)
545 struct dm_thin_new_mapping
*m
= context
;
546 struct pool
*pool
= m
->tc
->pool
;
548 m
->err
= read_err
|| write_err
? -EIO
: 0;
550 spin_lock_irqsave(&pool
->lock
, flags
);
552 __maybe_add_mapping(m
);
553 spin_unlock_irqrestore(&pool
->lock
, flags
);
556 static void overwrite_endio(struct bio
*bio
, int err
)
559 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
560 struct dm_thin_new_mapping
*m
= h
->overwrite_mapping
;
561 struct pool
*pool
= m
->tc
->pool
;
565 spin_lock_irqsave(&pool
->lock
, flags
);
567 __maybe_add_mapping(m
);
568 spin_unlock_irqrestore(&pool
->lock
, flags
);
571 /*----------------------------------------------------------------*/
578 * Prepared mapping jobs.
582 * This sends the bios in the cell back to the deferred_bios list.
584 static void cell_defer(struct thin_c
*tc
, struct dm_bio_prison_cell
*cell
)
586 struct pool
*pool
= tc
->pool
;
589 spin_lock_irqsave(&pool
->lock
, flags
);
590 cell_release(pool
, cell
, &pool
->deferred_bios
);
591 spin_unlock_irqrestore(&tc
->pool
->lock
, flags
);
597 * Same as cell_defer above, except it omits the original holder of the cell.
599 static void cell_defer_no_holder(struct thin_c
*tc
, struct dm_bio_prison_cell
*cell
)
601 struct pool
*pool
= tc
->pool
;
604 spin_lock_irqsave(&pool
->lock
, flags
);
605 cell_release_no_holder(pool
, cell
, &pool
->deferred_bios
);
606 spin_unlock_irqrestore(&pool
->lock
, flags
);
611 static void process_prepared_mapping_fail(struct dm_thin_new_mapping
*m
)
614 m
->bio
->bi_end_io
= m
->saved_bi_end_io
;
615 cell_error(m
->tc
->pool
, m
->cell
);
617 mempool_free(m
, m
->tc
->pool
->mapping_pool
);
620 static void process_prepared_mapping(struct dm_thin_new_mapping
*m
)
622 struct thin_c
*tc
= m
->tc
;
623 struct pool
*pool
= tc
->pool
;
629 bio
->bi_end_io
= m
->saved_bi_end_io
;
632 cell_error(pool
, m
->cell
);
637 * Commit the prepared block into the mapping btree.
638 * Any I/O for this block arriving after this point will get
639 * remapped to it directly.
641 r
= dm_thin_insert_block(tc
->td
, m
->virt_block
, m
->data_block
);
643 DMERR_LIMIT("%s: dm_thin_insert_block() failed: error = %d",
644 dm_device_name(pool
->pool_md
), r
);
645 set_pool_mode(pool
, PM_READ_ONLY
);
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 remap_and_issue(tc
, m
->bio
, m
->data_block
);
688 bio_endio(m
->bio
, 0);
690 mempool_free(m
, tc
->pool
->mapping_pool
);
693 static void process_prepared_discard(struct dm_thin_new_mapping
*m
)
696 struct thin_c
*tc
= m
->tc
;
698 r
= dm_thin_remove_block(tc
->td
, m
->virt_block
);
700 DMERR_LIMIT("dm_thin_remove_block() failed");
702 process_prepared_discard_passdown(m
);
705 static void process_prepared(struct pool
*pool
, struct list_head
*head
,
706 process_mapping_fn
*fn
)
709 struct list_head maps
;
710 struct dm_thin_new_mapping
*m
, *tmp
;
712 INIT_LIST_HEAD(&maps
);
713 spin_lock_irqsave(&pool
->lock
, flags
);
714 list_splice_init(head
, &maps
);
715 spin_unlock_irqrestore(&pool
->lock
, flags
);
717 list_for_each_entry_safe(m
, tmp
, &maps
, list
)
724 static int io_overlaps_block(struct pool
*pool
, struct bio
*bio
)
726 return bio
->bi_size
== (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
);
887 * A non-zero return indicates read_only or fail_io mode.
888 * Many callers don't care about the return value.
890 static int commit(struct pool
*pool
)
894 if (get_pool_mode(pool
) != PM_WRITE
)
897 r
= dm_pool_commit_metadata(pool
->pmd
);
899 DMERR_LIMIT("%s: dm_pool_commit_metadata failed: error = %d",
900 dm_device_name(pool
->pool_md
), r
);
901 set_pool_mode(pool
, PM_READ_ONLY
);
907 static int alloc_data_block(struct thin_c
*tc
, dm_block_t
*result
)
910 dm_block_t free_blocks
;
912 struct pool
*pool
= tc
->pool
;
915 * Once no_free_space is set we must not allow allocation to succeed.
916 * Otherwise it is difficult to explain, debug, test and support.
918 if (pool
->no_free_space
)
921 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
925 if (free_blocks
<= pool
->low_water_blocks
&& !pool
->low_water_triggered
) {
926 DMWARN("%s: reached low water mark for data device: sending event.",
927 dm_device_name(pool
->pool_md
));
928 spin_lock_irqsave(&pool
->lock
, flags
);
929 pool
->low_water_triggered
= 1;
930 spin_unlock_irqrestore(&pool
->lock
, flags
);
931 dm_table_event(pool
->ti
->table
);
936 * Try to commit to see if that will free up some
943 r
= dm_pool_get_free_block_count(pool
->pmd
, &free_blocks
);
948 * If we still have no space we set a flag to avoid
949 * doing all this checking and return -ENOSPC. This
950 * flag serves as a latch that disallows allocations from
951 * this pool until the admin takes action (e.g. resize or
955 DMWARN("%s: no free data space available.",
956 dm_device_name(pool
->pool_md
));
957 spin_lock_irqsave(&pool
->lock
, flags
);
958 pool
->no_free_space
= 1;
959 spin_unlock_irqrestore(&pool
->lock
, flags
);
964 r
= dm_pool_alloc_data_block(pool
->pmd
, result
);
967 !dm_pool_get_free_metadata_block_count(pool
->pmd
, &free_blocks
) &&
969 DMWARN("%s: no free metadata space available.",
970 dm_device_name(pool
->pool_md
));
971 set_pool_mode(pool
, PM_READ_ONLY
);
980 * If we have run out of space, queue bios until the device is
981 * resumed, presumably after having been reloaded with more space.
983 static void retry_on_resume(struct bio
*bio
)
985 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
986 struct thin_c
*tc
= h
->tc
;
987 struct pool
*pool
= tc
->pool
;
990 spin_lock_irqsave(&pool
->lock
, flags
);
991 bio_list_add(&pool
->retry_on_resume_list
, bio
);
992 spin_unlock_irqrestore(&pool
->lock
, flags
);
995 static void no_space(struct pool
*pool
, struct dm_bio_prison_cell
*cell
)
998 struct bio_list bios
;
1000 bio_list_init(&bios
);
1001 cell_release(pool
, cell
, &bios
);
1003 while ((bio
= bio_list_pop(&bios
)))
1004 retry_on_resume(bio
);
1007 static void process_discard(struct thin_c
*tc
, struct bio
*bio
)
1010 unsigned long flags
;
1011 struct pool
*pool
= tc
->pool
;
1012 struct dm_bio_prison_cell
*cell
, *cell2
;
1013 struct dm_cell_key key
, key2
;
1014 dm_block_t block
= get_bio_block(tc
, bio
);
1015 struct dm_thin_lookup_result lookup_result
;
1016 struct dm_thin_new_mapping
*m
;
1018 build_virtual_key(tc
->td
, block
, &key
);
1019 if (bio_detain(tc
->pool
, &key
, bio
, &cell
))
1022 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1026 * Check nobody is fiddling with this pool block. This can
1027 * happen if someone's in the process of breaking sharing
1030 build_data_key(tc
->td
, lookup_result
.block
, &key2
);
1031 if (bio_detain(tc
->pool
, &key2
, bio
, &cell2
)) {
1032 cell_defer_no_holder(tc
, cell
);
1036 if (io_overlaps_block(pool
, bio
)) {
1038 * IO may still be going to the destination block. We must
1039 * quiesce before we can do the removal.
1041 m
= get_next_mapping(pool
);
1043 m
->pass_discard
= (!lookup_result
.shared
) && pool
->pf
.discard_passdown
;
1044 m
->virt_block
= block
;
1045 m
->data_block
= lookup_result
.block
;
1051 if (!dm_deferred_set_add_work(pool
->all_io_ds
, &m
->list
)) {
1052 spin_lock_irqsave(&pool
->lock
, flags
);
1053 list_add(&m
->list
, &pool
->prepared_discards
);
1054 spin_unlock_irqrestore(&pool
->lock
, flags
);
1058 inc_all_io_entry(pool
, bio
);
1059 cell_defer_no_holder(tc
, cell
);
1060 cell_defer_no_holder(tc
, cell2
);
1063 * The DM core makes sure that the discard doesn't span
1064 * a block boundary. So we submit the discard of a
1065 * partial block appropriately.
1067 if ((!lookup_result
.shared
) && pool
->pf
.discard_passdown
)
1068 remap_and_issue(tc
, bio
, lookup_result
.block
);
1076 * It isn't provisioned, just forget it.
1078 cell_defer_no_holder(tc
, cell
);
1083 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1085 cell_defer_no_holder(tc
, cell
);
1091 static void break_sharing(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1092 struct dm_cell_key
*key
,
1093 struct dm_thin_lookup_result
*lookup_result
,
1094 struct dm_bio_prison_cell
*cell
)
1097 dm_block_t data_block
;
1098 struct pool
*pool
= tc
->pool
;
1100 r
= alloc_data_block(tc
, &data_block
);
1103 schedule_internal_copy(tc
, block
, lookup_result
->block
,
1104 data_block
, cell
, bio
);
1108 no_space(pool
, cell
);
1112 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1114 set_pool_mode(pool
, PM_READ_ONLY
);
1115 cell_error(pool
, cell
);
1120 static void process_shared_bio(struct thin_c
*tc
, struct bio
*bio
,
1122 struct dm_thin_lookup_result
*lookup_result
)
1124 struct dm_bio_prison_cell
*cell
;
1125 struct pool
*pool
= tc
->pool
;
1126 struct dm_cell_key key
;
1129 * If cell is already occupied, then sharing is already in the process
1130 * of being broken so we have nothing further to do here.
1132 build_data_key(tc
->td
, lookup_result
->block
, &key
);
1133 if (bio_detain(pool
, &key
, bio
, &cell
))
1136 if (bio_data_dir(bio
) == WRITE
&& bio
->bi_size
)
1137 break_sharing(tc
, bio
, block
, &key
, lookup_result
, cell
);
1139 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1141 h
->shared_read_entry
= dm_deferred_entry_inc(pool
->shared_read_ds
);
1142 inc_all_io_entry(pool
, bio
);
1143 cell_defer_no_holder(tc
, cell
);
1145 remap_and_issue(tc
, bio
, lookup_result
->block
);
1149 static void provision_block(struct thin_c
*tc
, struct bio
*bio
, dm_block_t block
,
1150 struct dm_bio_prison_cell
*cell
)
1153 dm_block_t data_block
;
1154 struct pool
*pool
= tc
->pool
;
1157 * Remap empty bios (flushes) immediately, without provisioning.
1159 if (!bio
->bi_size
) {
1160 inc_all_io_entry(pool
, bio
);
1161 cell_defer_no_holder(tc
, cell
);
1163 remap_and_issue(tc
, bio
, 0);
1168 * Fill read bios with zeroes and complete them immediately.
1170 if (bio_data_dir(bio
) == READ
) {
1172 cell_defer_no_holder(tc
, cell
);
1177 r
= alloc_data_block(tc
, &data_block
);
1181 schedule_external_copy(tc
, block
, data_block
, cell
, bio
);
1183 schedule_zero(tc
, block
, data_block
, cell
, bio
);
1187 no_space(pool
, cell
);
1191 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1193 set_pool_mode(pool
, PM_READ_ONLY
);
1194 cell_error(pool
, cell
);
1199 static void process_bio(struct thin_c
*tc
, struct bio
*bio
)
1202 struct pool
*pool
= tc
->pool
;
1203 dm_block_t block
= get_bio_block(tc
, bio
);
1204 struct dm_bio_prison_cell
*cell
;
1205 struct dm_cell_key key
;
1206 struct dm_thin_lookup_result lookup_result
;
1209 * If cell is already occupied, then the block is already
1210 * being provisioned so we have nothing further to do here.
1212 build_virtual_key(tc
->td
, block
, &key
);
1213 if (bio_detain(pool
, &key
, bio
, &cell
))
1216 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1219 if (lookup_result
.shared
) {
1220 process_shared_bio(tc
, bio
, block
, &lookup_result
);
1221 cell_defer_no_holder(tc
, cell
); /* FIXME: pass this cell into process_shared? */
1223 inc_all_io_entry(pool
, bio
);
1224 cell_defer_no_holder(tc
, cell
);
1226 remap_and_issue(tc
, bio
, lookup_result
.block
);
1231 if (bio_data_dir(bio
) == READ
&& tc
->origin_dev
) {
1232 inc_all_io_entry(pool
, bio
);
1233 cell_defer_no_holder(tc
, cell
);
1235 remap_to_origin_and_issue(tc
, bio
);
1237 provision_block(tc
, bio
, block
, cell
);
1241 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1243 cell_defer_no_holder(tc
, cell
);
1249 static void process_bio_read_only(struct thin_c
*tc
, struct bio
*bio
)
1252 int rw
= bio_data_dir(bio
);
1253 dm_block_t block
= get_bio_block(tc
, bio
);
1254 struct dm_thin_lookup_result lookup_result
;
1256 r
= dm_thin_find_block(tc
->td
, block
, 1, &lookup_result
);
1259 if (lookup_result
.shared
&& (rw
== WRITE
) && bio
->bi_size
)
1262 inc_all_io_entry(tc
->pool
, bio
);
1263 remap_and_issue(tc
, bio
, lookup_result
.block
);
1273 if (tc
->origin_dev
) {
1274 inc_all_io_entry(tc
->pool
, bio
);
1275 remap_to_origin_and_issue(tc
, bio
);
1284 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1291 static void process_bio_fail(struct thin_c
*tc
, struct bio
*bio
)
1297 * FIXME: should we also commit due to size of transaction, measured in
1300 static int need_commit_due_to_time(struct pool
*pool
)
1302 return jiffies
< pool
->last_commit_jiffies
||
1303 jiffies
> pool
->last_commit_jiffies
+ COMMIT_PERIOD
;
1306 static void process_deferred_bios(struct pool
*pool
)
1308 unsigned long flags
;
1310 struct bio_list bios
;
1312 bio_list_init(&bios
);
1314 spin_lock_irqsave(&pool
->lock
, flags
);
1315 bio_list_merge(&bios
, &pool
->deferred_bios
);
1316 bio_list_init(&pool
->deferred_bios
);
1317 spin_unlock_irqrestore(&pool
->lock
, flags
);
1319 while ((bio
= bio_list_pop(&bios
))) {
1320 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1321 struct thin_c
*tc
= h
->tc
;
1324 * If we've got no free new_mapping structs, and processing
1325 * this bio might require one, we pause until there are some
1326 * prepared mappings to process.
1328 if (ensure_next_mapping(pool
)) {
1329 spin_lock_irqsave(&pool
->lock
, flags
);
1330 bio_list_merge(&pool
->deferred_bios
, &bios
);
1331 spin_unlock_irqrestore(&pool
->lock
, flags
);
1336 if (bio
->bi_rw
& REQ_DISCARD
)
1337 pool
->process_discard(tc
, bio
);
1339 pool
->process_bio(tc
, bio
);
1343 * If there are any deferred flush bios, we must commit
1344 * the metadata before issuing them.
1346 bio_list_init(&bios
);
1347 spin_lock_irqsave(&pool
->lock
, flags
);
1348 bio_list_merge(&bios
, &pool
->deferred_flush_bios
);
1349 bio_list_init(&pool
->deferred_flush_bios
);
1350 spin_unlock_irqrestore(&pool
->lock
, flags
);
1352 if (bio_list_empty(&bios
) && !need_commit_due_to_time(pool
))
1356 while ((bio
= bio_list_pop(&bios
)))
1360 pool
->last_commit_jiffies
= jiffies
;
1362 while ((bio
= bio_list_pop(&bios
)))
1363 generic_make_request(bio
);
1366 static void do_worker(struct work_struct
*ws
)
1368 struct pool
*pool
= container_of(ws
, struct pool
, worker
);
1370 process_prepared(pool
, &pool
->prepared_mappings
, &pool
->process_prepared_mapping
);
1371 process_prepared(pool
, &pool
->prepared_discards
, &pool
->process_prepared_discard
);
1372 process_deferred_bios(pool
);
1376 * We want to commit periodically so that not too much
1377 * unwritten data builds up.
1379 static void do_waker(struct work_struct
*ws
)
1381 struct pool
*pool
= container_of(to_delayed_work(ws
), struct pool
, waker
);
1383 queue_delayed_work(pool
->wq
, &pool
->waker
, COMMIT_PERIOD
);
1386 /*----------------------------------------------------------------*/
1388 static enum pool_mode
get_pool_mode(struct pool
*pool
)
1390 return pool
->pf
.mode
;
1393 static void set_pool_mode(struct pool
*pool
, enum pool_mode mode
)
1397 pool
->pf
.mode
= mode
;
1401 DMERR("%s: switching pool to failure mode",
1402 dm_device_name(pool
->pool_md
));
1403 dm_pool_metadata_read_only(pool
->pmd
);
1404 pool
->process_bio
= process_bio_fail
;
1405 pool
->process_discard
= process_bio_fail
;
1406 pool
->process_prepared_mapping
= process_prepared_mapping_fail
;
1407 pool
->process_prepared_discard
= process_prepared_discard_fail
;
1411 DMERR("%s: switching pool to read-only mode",
1412 dm_device_name(pool
->pool_md
));
1413 r
= dm_pool_abort_metadata(pool
->pmd
);
1415 DMERR("%s: aborting transaction failed",
1416 dm_device_name(pool
->pool_md
));
1417 set_pool_mode(pool
, PM_FAIL
);
1419 dm_pool_metadata_read_only(pool
->pmd
);
1420 pool
->process_bio
= process_bio_read_only
;
1421 pool
->process_discard
= process_discard
;
1422 pool
->process_prepared_mapping
= process_prepared_mapping_fail
;
1423 pool
->process_prepared_discard
= process_prepared_discard_passdown
;
1428 dm_pool_metadata_read_write(pool
->pmd
);
1429 pool
->process_bio
= process_bio
;
1430 pool
->process_discard
= process_discard
;
1431 pool
->process_prepared_mapping
= process_prepared_mapping
;
1432 pool
->process_prepared_discard
= process_prepared_discard
;
1437 /*----------------------------------------------------------------*/
1440 * Mapping functions.
1444 * Called only while mapping a thin bio to hand it over to the workqueue.
1446 static void thin_defer_bio(struct thin_c
*tc
, struct bio
*bio
)
1448 unsigned long flags
;
1449 struct pool
*pool
= tc
->pool
;
1451 spin_lock_irqsave(&pool
->lock
, flags
);
1452 bio_list_add(&pool
->deferred_bios
, bio
);
1453 spin_unlock_irqrestore(&pool
->lock
, flags
);
1458 static void thin_hook_bio(struct thin_c
*tc
, struct bio
*bio
)
1460 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
1463 h
->shared_read_entry
= NULL
;
1464 h
->all_io_entry
= NULL
;
1465 h
->overwrite_mapping
= NULL
;
1469 * Non-blocking function called from the thin target's map function.
1471 static int thin_bio_map(struct dm_target
*ti
, struct bio
*bio
)
1474 struct thin_c
*tc
= ti
->private;
1475 dm_block_t block
= get_bio_block(tc
, bio
);
1476 struct dm_thin_device
*td
= tc
->td
;
1477 struct dm_thin_lookup_result result
;
1478 struct dm_bio_prison_cell cell1
, cell2
;
1479 struct dm_bio_prison_cell
*cell_result
;
1480 struct dm_cell_key key
;
1482 thin_hook_bio(tc
, bio
);
1484 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
1486 return DM_MAPIO_SUBMITTED
;
1489 if (bio
->bi_rw
& (REQ_DISCARD
| REQ_FLUSH
| REQ_FUA
)) {
1490 thin_defer_bio(tc
, bio
);
1491 return DM_MAPIO_SUBMITTED
;
1494 r
= dm_thin_find_block(td
, block
, 0, &result
);
1497 * Note that we defer readahead too.
1501 if (unlikely(result
.shared
)) {
1503 * We have a race condition here between the
1504 * result.shared value returned by the lookup and
1505 * snapshot creation, which may cause new
1508 * To avoid this always quiesce the origin before
1509 * taking the snap. You want to do this anyway to
1510 * ensure a consistent application view
1513 * More distant ancestors are irrelevant. The
1514 * shared flag will be set in their case.
1516 thin_defer_bio(tc
, bio
);
1517 return DM_MAPIO_SUBMITTED
;
1520 build_virtual_key(tc
->td
, block
, &key
);
1521 if (dm_bio_detain(tc
->pool
->prison
, &key
, bio
, &cell1
, &cell_result
))
1522 return DM_MAPIO_SUBMITTED
;
1524 build_data_key(tc
->td
, result
.block
, &key
);
1525 if (dm_bio_detain(tc
->pool
->prison
, &key
, bio
, &cell2
, &cell_result
)) {
1526 cell_defer_no_holder_no_free(tc
, &cell1
);
1527 return DM_MAPIO_SUBMITTED
;
1530 inc_all_io_entry(tc
->pool
, bio
);
1531 cell_defer_no_holder_no_free(tc
, &cell2
);
1532 cell_defer_no_holder_no_free(tc
, &cell1
);
1534 remap(tc
, bio
, result
.block
);
1535 return DM_MAPIO_REMAPPED
;
1538 if (get_pool_mode(tc
->pool
) == PM_READ_ONLY
) {
1540 * This block isn't provisioned, and we have no way
1541 * of doing so. Just error it.
1544 return DM_MAPIO_SUBMITTED
;
1550 * In future, the failed dm_thin_find_block above could
1551 * provide the hint to load the metadata into cache.
1553 thin_defer_bio(tc
, bio
);
1554 return DM_MAPIO_SUBMITTED
;
1558 * Must always call bio_io_error on failure.
1559 * dm_thin_find_block can fail with -EINVAL if the
1560 * pool is switched to fail-io mode.
1563 return DM_MAPIO_SUBMITTED
;
1567 static int pool_is_congested(struct dm_target_callbacks
*cb
, int bdi_bits
)
1570 unsigned long flags
;
1571 struct pool_c
*pt
= container_of(cb
, struct pool_c
, callbacks
);
1573 spin_lock_irqsave(&pt
->pool
->lock
, flags
);
1574 r
= !bio_list_empty(&pt
->pool
->retry_on_resume_list
);
1575 spin_unlock_irqrestore(&pt
->pool
->lock
, flags
);
1578 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1579 r
= bdi_congested(&q
->backing_dev_info
, bdi_bits
);
1585 static void __requeue_bios(struct pool
*pool
)
1587 bio_list_merge(&pool
->deferred_bios
, &pool
->retry_on_resume_list
);
1588 bio_list_init(&pool
->retry_on_resume_list
);
1591 /*----------------------------------------------------------------
1592 * Binding of control targets to a pool object
1593 *--------------------------------------------------------------*/
1594 static bool data_dev_supports_discard(struct pool_c
*pt
)
1596 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
1598 return q
&& blk_queue_discard(q
);
1601 static bool is_factor(sector_t block_size
, uint32_t n
)
1603 return !sector_div(block_size
, n
);
1607 * If discard_passdown was enabled verify that the data device
1608 * supports discards. Disable discard_passdown if not.
1610 static void disable_passdown_if_not_supported(struct pool_c
*pt
)
1612 struct pool
*pool
= pt
->pool
;
1613 struct block_device
*data_bdev
= pt
->data_dev
->bdev
;
1614 struct queue_limits
*data_limits
= &bdev_get_queue(data_bdev
)->limits
;
1615 sector_t block_size
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
1616 const char *reason
= NULL
;
1617 char buf
[BDEVNAME_SIZE
];
1619 if (!pt
->adjusted_pf
.discard_passdown
)
1622 if (!data_dev_supports_discard(pt
))
1623 reason
= "discard unsupported";
1625 else if (data_limits
->max_discard_sectors
< pool
->sectors_per_block
)
1626 reason
= "max discard sectors smaller than a block";
1628 else if (data_limits
->discard_granularity
> block_size
)
1629 reason
= "discard granularity larger than a block";
1631 else if (!is_factor(block_size
, data_limits
->discard_granularity
))
1632 reason
= "discard granularity not a factor of block size";
1635 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev
, buf
), reason
);
1636 pt
->adjusted_pf
.discard_passdown
= false;
1640 static int bind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1642 struct pool_c
*pt
= ti
->private;
1645 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
1647 enum pool_mode old_mode
= pool
->pf
.mode
;
1648 enum pool_mode new_mode
= pt
->adjusted_pf
.mode
;
1651 * If we were in PM_FAIL mode, rollback of metadata failed. We're
1652 * not going to recover without a thin_repair. So we never let the
1653 * pool move out of the old mode. On the other hand a PM_READ_ONLY
1654 * may have been due to a lack of metadata or data space, and may
1655 * now work (ie. if the underlying devices have been resized).
1657 if (old_mode
== PM_FAIL
)
1658 new_mode
= old_mode
;
1661 pool
->low_water_blocks
= pt
->low_water_blocks
;
1662 pool
->pf
= pt
->adjusted_pf
;
1664 set_pool_mode(pool
, new_mode
);
1669 static void unbind_control_target(struct pool
*pool
, struct dm_target
*ti
)
1675 /*----------------------------------------------------------------
1677 *--------------------------------------------------------------*/
1678 /* Initialize pool features. */
1679 static void pool_features_init(struct pool_features
*pf
)
1681 pf
->mode
= PM_WRITE
;
1682 pf
->zero_new_blocks
= true;
1683 pf
->discard_enabled
= true;
1684 pf
->discard_passdown
= true;
1687 static void __pool_destroy(struct pool
*pool
)
1689 __pool_table_remove(pool
);
1691 if (dm_pool_metadata_close(pool
->pmd
) < 0)
1692 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1694 dm_bio_prison_destroy(pool
->prison
);
1695 dm_kcopyd_client_destroy(pool
->copier
);
1698 destroy_workqueue(pool
->wq
);
1700 if (pool
->next_mapping
)
1701 mempool_free(pool
->next_mapping
, pool
->mapping_pool
);
1702 mempool_destroy(pool
->mapping_pool
);
1703 dm_deferred_set_destroy(pool
->shared_read_ds
);
1704 dm_deferred_set_destroy(pool
->all_io_ds
);
1708 static struct kmem_cache
*_new_mapping_cache
;
1710 static struct pool
*pool_create(struct mapped_device
*pool_md
,
1711 struct block_device
*metadata_dev
,
1712 unsigned long block_size
,
1713 int read_only
, char **error
)
1718 struct dm_pool_metadata
*pmd
;
1719 bool format_device
= read_only
? false : true;
1721 pmd
= dm_pool_metadata_open(metadata_dev
, block_size
, format_device
);
1723 *error
= "Error creating metadata object";
1724 return (struct pool
*)pmd
;
1727 pool
= kmalloc(sizeof(*pool
), GFP_KERNEL
);
1729 *error
= "Error allocating memory for pool";
1730 err_p
= ERR_PTR(-ENOMEM
);
1735 pool
->sectors_per_block
= block_size
;
1736 if (block_size
& (block_size
- 1))
1737 pool
->sectors_per_block_shift
= -1;
1739 pool
->sectors_per_block_shift
= __ffs(block_size
);
1740 pool
->low_water_blocks
= 0;
1741 pool_features_init(&pool
->pf
);
1742 pool
->prison
= dm_bio_prison_create(PRISON_CELLS
);
1743 if (!pool
->prison
) {
1744 *error
= "Error creating pool's bio prison";
1745 err_p
= ERR_PTR(-ENOMEM
);
1749 pool
->copier
= dm_kcopyd_client_create(&dm_kcopyd_throttle
);
1750 if (IS_ERR(pool
->copier
)) {
1751 r
= PTR_ERR(pool
->copier
);
1752 *error
= "Error creating pool's kcopyd client";
1754 goto bad_kcopyd_client
;
1758 * Create singlethreaded workqueue that will service all devices
1759 * that use this metadata.
1761 pool
->wq
= alloc_ordered_workqueue("dm-" DM_MSG_PREFIX
, WQ_MEM_RECLAIM
);
1763 *error
= "Error creating pool's workqueue";
1764 err_p
= ERR_PTR(-ENOMEM
);
1768 INIT_WORK(&pool
->worker
, do_worker
);
1769 INIT_DELAYED_WORK(&pool
->waker
, do_waker
);
1770 spin_lock_init(&pool
->lock
);
1771 bio_list_init(&pool
->deferred_bios
);
1772 bio_list_init(&pool
->deferred_flush_bios
);
1773 INIT_LIST_HEAD(&pool
->prepared_mappings
);
1774 INIT_LIST_HEAD(&pool
->prepared_discards
);
1775 pool
->low_water_triggered
= 0;
1776 pool
->no_free_space
= 0;
1777 bio_list_init(&pool
->retry_on_resume_list
);
1779 pool
->shared_read_ds
= dm_deferred_set_create();
1780 if (!pool
->shared_read_ds
) {
1781 *error
= "Error creating pool's shared read deferred set";
1782 err_p
= ERR_PTR(-ENOMEM
);
1783 goto bad_shared_read_ds
;
1786 pool
->all_io_ds
= dm_deferred_set_create();
1787 if (!pool
->all_io_ds
) {
1788 *error
= "Error creating pool's all io deferred set";
1789 err_p
= ERR_PTR(-ENOMEM
);
1793 pool
->next_mapping
= NULL
;
1794 pool
->mapping_pool
= mempool_create_slab_pool(MAPPING_POOL_SIZE
,
1795 _new_mapping_cache
);
1796 if (!pool
->mapping_pool
) {
1797 *error
= "Error creating pool's mapping mempool";
1798 err_p
= ERR_PTR(-ENOMEM
);
1799 goto bad_mapping_pool
;
1802 pool
->ref_count
= 1;
1803 pool
->last_commit_jiffies
= jiffies
;
1804 pool
->pool_md
= pool_md
;
1805 pool
->md_dev
= metadata_dev
;
1806 __pool_table_insert(pool
);
1811 dm_deferred_set_destroy(pool
->all_io_ds
);
1813 dm_deferred_set_destroy(pool
->shared_read_ds
);
1815 destroy_workqueue(pool
->wq
);
1817 dm_kcopyd_client_destroy(pool
->copier
);
1819 dm_bio_prison_destroy(pool
->prison
);
1823 if (dm_pool_metadata_close(pmd
))
1824 DMWARN("%s: dm_pool_metadata_close() failed.", __func__
);
1829 static void __pool_inc(struct pool
*pool
)
1831 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1835 static void __pool_dec(struct pool
*pool
)
1837 BUG_ON(!mutex_is_locked(&dm_thin_pool_table
.mutex
));
1838 BUG_ON(!pool
->ref_count
);
1839 if (!--pool
->ref_count
)
1840 __pool_destroy(pool
);
1843 static struct pool
*__pool_find(struct mapped_device
*pool_md
,
1844 struct block_device
*metadata_dev
,
1845 unsigned long block_size
, int read_only
,
1846 char **error
, int *created
)
1848 struct pool
*pool
= __pool_table_lookup_metadata_dev(metadata_dev
);
1851 if (pool
->pool_md
!= pool_md
) {
1852 *error
= "metadata device already in use by a pool";
1853 return ERR_PTR(-EBUSY
);
1858 pool
= __pool_table_lookup(pool_md
);
1860 if (pool
->md_dev
!= metadata_dev
) {
1861 *error
= "different pool cannot replace a pool";
1862 return ERR_PTR(-EINVAL
);
1867 pool
= pool_create(pool_md
, metadata_dev
, block_size
, read_only
, error
);
1875 /*----------------------------------------------------------------
1876 * Pool target methods
1877 *--------------------------------------------------------------*/
1878 static void pool_dtr(struct dm_target
*ti
)
1880 struct pool_c
*pt
= ti
->private;
1882 mutex_lock(&dm_thin_pool_table
.mutex
);
1884 unbind_control_target(pt
->pool
, ti
);
1885 __pool_dec(pt
->pool
);
1886 dm_put_device(ti
, pt
->metadata_dev
);
1887 dm_put_device(ti
, pt
->data_dev
);
1890 mutex_unlock(&dm_thin_pool_table
.mutex
);
1893 static int parse_pool_features(struct dm_arg_set
*as
, struct pool_features
*pf
,
1894 struct dm_target
*ti
)
1898 const char *arg_name
;
1900 static struct dm_arg _args
[] = {
1901 {0, 3, "Invalid number of pool feature arguments"},
1905 * No feature arguments supplied.
1910 r
= dm_read_arg_group(_args
, as
, &argc
, &ti
->error
);
1914 while (argc
&& !r
) {
1915 arg_name
= dm_shift_arg(as
);
1918 if (!strcasecmp(arg_name
, "skip_block_zeroing"))
1919 pf
->zero_new_blocks
= false;
1921 else if (!strcasecmp(arg_name
, "ignore_discard"))
1922 pf
->discard_enabled
= false;
1924 else if (!strcasecmp(arg_name
, "no_discard_passdown"))
1925 pf
->discard_passdown
= false;
1927 else if (!strcasecmp(arg_name
, "read_only"))
1928 pf
->mode
= PM_READ_ONLY
;
1931 ti
->error
= "Unrecognised pool feature requested";
1940 static void metadata_low_callback(void *context
)
1942 struct pool
*pool
= context
;
1944 DMWARN("%s: reached low water mark for metadata device: sending event.",
1945 dm_device_name(pool
->pool_md
));
1947 dm_table_event(pool
->ti
->table
);
1950 static sector_t
get_metadata_dev_size(struct block_device
*bdev
)
1952 sector_t metadata_dev_size
= i_size_read(bdev
->bd_inode
) >> SECTOR_SHIFT
;
1953 char buffer
[BDEVNAME_SIZE
];
1955 if (metadata_dev_size
> THIN_METADATA_MAX_SECTORS_WARNING
) {
1956 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1957 bdevname(bdev
, buffer
), THIN_METADATA_MAX_SECTORS
);
1958 metadata_dev_size
= THIN_METADATA_MAX_SECTORS_WARNING
;
1961 return metadata_dev_size
;
1964 static dm_block_t
get_metadata_dev_size_in_blocks(struct block_device
*bdev
)
1966 sector_t metadata_dev_size
= get_metadata_dev_size(bdev
);
1968 sector_div(metadata_dev_size
, THIN_METADATA_BLOCK_SIZE
>> SECTOR_SHIFT
);
1970 return metadata_dev_size
;
1974 * When a metadata threshold is crossed a dm event is triggered, and
1975 * userland should respond by growing the metadata device. We could let
1976 * userland set the threshold, like we do with the data threshold, but I'm
1977 * not sure they know enough to do this well.
1979 static dm_block_t
calc_metadata_threshold(struct pool_c
*pt
)
1982 * 4M is ample for all ops with the possible exception of thin
1983 * device deletion which is harmless if it fails (just retry the
1984 * delete after you've grown the device).
1986 dm_block_t quarter
= get_metadata_dev_size_in_blocks(pt
->metadata_dev
->bdev
) / 4;
1987 return min((dm_block_t
)1024ULL /* 4M */, quarter
);
1991 * thin-pool <metadata dev> <data dev>
1992 * <data block size (sectors)>
1993 * <low water mark (blocks)>
1994 * [<#feature args> [<arg>]*]
1996 * Optional feature arguments are:
1997 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1998 * ignore_discard: disable discard
1999 * no_discard_passdown: don't pass discards down to the data device
2001 static int pool_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
2003 int r
, pool_created
= 0;
2006 struct pool_features pf
;
2007 struct dm_arg_set as
;
2008 struct dm_dev
*data_dev
;
2009 unsigned long block_size
;
2010 dm_block_t low_water_blocks
;
2011 struct dm_dev
*metadata_dev
;
2012 fmode_t metadata_mode
;
2015 * FIXME Remove validation from scope of lock.
2017 mutex_lock(&dm_thin_pool_table
.mutex
);
2020 ti
->error
= "Invalid argument count";
2029 * Set default pool features.
2031 pool_features_init(&pf
);
2033 dm_consume_args(&as
, 4);
2034 r
= parse_pool_features(&as
, &pf
, ti
);
2038 metadata_mode
= FMODE_READ
| ((pf
.mode
== PM_READ_ONLY
) ? 0 : FMODE_WRITE
);
2039 r
= dm_get_device(ti
, argv
[0], metadata_mode
, &metadata_dev
);
2041 ti
->error
= "Error opening metadata block device";
2046 * Run for the side-effect of possibly issuing a warning if the
2047 * device is too big.
2049 (void) get_metadata_dev_size(metadata_dev
->bdev
);
2051 r
= dm_get_device(ti
, argv
[1], FMODE_READ
| FMODE_WRITE
, &data_dev
);
2053 ti
->error
= "Error getting data device";
2057 if (kstrtoul(argv
[2], 10, &block_size
) || !block_size
||
2058 block_size
< DATA_DEV_BLOCK_SIZE_MIN_SECTORS
||
2059 block_size
> DATA_DEV_BLOCK_SIZE_MAX_SECTORS
||
2060 block_size
& (DATA_DEV_BLOCK_SIZE_MIN_SECTORS
- 1)) {
2061 ti
->error
= "Invalid block size";
2066 if (kstrtoull(argv
[3], 10, (unsigned long long *)&low_water_blocks
)) {
2067 ti
->error
= "Invalid low water mark";
2072 pt
= kzalloc(sizeof(*pt
), GFP_KERNEL
);
2078 pool
= __pool_find(dm_table_get_md(ti
->table
), metadata_dev
->bdev
,
2079 block_size
, pf
.mode
== PM_READ_ONLY
, &ti
->error
, &pool_created
);
2086 * 'pool_created' reflects whether this is the first table load.
2087 * Top level discard support is not allowed to be changed after
2088 * initial load. This would require a pool reload to trigger thin
2091 if (!pool_created
&& pf
.discard_enabled
!= pool
->pf
.discard_enabled
) {
2092 ti
->error
= "Discard support cannot be disabled once enabled";
2094 goto out_flags_changed
;
2099 pt
->metadata_dev
= metadata_dev
;
2100 pt
->data_dev
= data_dev
;
2101 pt
->low_water_blocks
= low_water_blocks
;
2102 pt
->adjusted_pf
= pt
->requested_pf
= pf
;
2103 ti
->num_flush_bios
= 1;
2106 * Only need to enable discards if the pool should pass
2107 * them down to the data device. The thin device's discard
2108 * processing will cause mappings to be removed from the btree.
2110 ti
->discard_zeroes_data_unsupported
= true;
2111 if (pf
.discard_enabled
&& pf
.discard_passdown
) {
2112 ti
->num_discard_bios
= 1;
2115 * Setting 'discards_supported' circumvents the normal
2116 * stacking of discard limits (this keeps the pool and
2117 * thin devices' discard limits consistent).
2119 ti
->discards_supported
= true;
2123 r
= dm_pool_register_metadata_threshold(pt
->pool
->pmd
,
2124 calc_metadata_threshold(pt
),
2125 metadata_low_callback
,
2130 pt
->callbacks
.congested_fn
= pool_is_congested
;
2131 dm_table_add_target_callbacks(ti
->table
, &pt
->callbacks
);
2133 mutex_unlock(&dm_thin_pool_table
.mutex
);
2142 dm_put_device(ti
, data_dev
);
2144 dm_put_device(ti
, metadata_dev
);
2146 mutex_unlock(&dm_thin_pool_table
.mutex
);
2151 static int pool_map(struct dm_target
*ti
, struct bio
*bio
)
2154 struct pool_c
*pt
= ti
->private;
2155 struct pool
*pool
= pt
->pool
;
2156 unsigned long flags
;
2159 * As this is a singleton target, ti->begin is always zero.
2161 spin_lock_irqsave(&pool
->lock
, flags
);
2162 bio
->bi_bdev
= pt
->data_dev
->bdev
;
2163 r
= DM_MAPIO_REMAPPED
;
2164 spin_unlock_irqrestore(&pool
->lock
, flags
);
2169 static int maybe_resize_data_dev(struct dm_target
*ti
, bool *need_commit
)
2172 struct pool_c
*pt
= ti
->private;
2173 struct pool
*pool
= pt
->pool
;
2174 sector_t data_size
= ti
->len
;
2175 dm_block_t sb_data_size
;
2177 *need_commit
= false;
2179 (void) sector_div(data_size
, pool
->sectors_per_block
);
2181 r
= dm_pool_get_data_dev_size(pool
->pmd
, &sb_data_size
);
2183 DMERR("%s: failed to retrieve data device size",
2184 dm_device_name(pool
->pool_md
));
2188 if (data_size
< sb_data_size
) {
2189 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
2190 dm_device_name(pool
->pool_md
),
2191 (unsigned long long)data_size
, sb_data_size
);
2194 } else if (data_size
> sb_data_size
) {
2195 r
= dm_pool_resize_data_dev(pool
->pmd
, data_size
);
2197 DMERR("%s: failed to resize data device",
2198 dm_device_name(pool
->pool_md
));
2199 set_pool_mode(pool
, PM_READ_ONLY
);
2203 *need_commit
= true;
2209 static int maybe_resize_metadata_dev(struct dm_target
*ti
, bool *need_commit
)
2212 struct pool_c
*pt
= ti
->private;
2213 struct pool
*pool
= pt
->pool
;
2214 dm_block_t metadata_dev_size
, sb_metadata_dev_size
;
2216 *need_commit
= false;
2218 metadata_dev_size
= get_metadata_dev_size_in_blocks(pool
->md_dev
);
2220 r
= dm_pool_get_metadata_dev_size(pool
->pmd
, &sb_metadata_dev_size
);
2222 DMERR("%s: failed to retrieve metadata device size",
2223 dm_device_name(pool
->pool_md
));
2227 if (metadata_dev_size
< sb_metadata_dev_size
) {
2228 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
2229 dm_device_name(pool
->pool_md
),
2230 metadata_dev_size
, sb_metadata_dev_size
);
2233 } else if (metadata_dev_size
> sb_metadata_dev_size
) {
2234 r
= dm_pool_resize_metadata_dev(pool
->pmd
, metadata_dev_size
);
2236 DMERR("%s: failed to resize metadata device",
2237 dm_device_name(pool
->pool_md
));
2241 *need_commit
= true;
2248 * Retrieves the number of blocks of the data device from
2249 * the superblock and compares it to the actual device size,
2250 * thus resizing the data device in case it has grown.
2252 * This both copes with opening preallocated data devices in the ctr
2253 * being followed by a resume
2255 * calling the resume method individually after userspace has
2256 * grown the data device in reaction to a table event.
2258 static int pool_preresume(struct dm_target
*ti
)
2261 bool need_commit1
, need_commit2
;
2262 struct pool_c
*pt
= ti
->private;
2263 struct pool
*pool
= pt
->pool
;
2266 * Take control of the pool object.
2268 r
= bind_control_target(pool
, ti
);
2272 r
= maybe_resize_data_dev(ti
, &need_commit1
);
2276 r
= maybe_resize_metadata_dev(ti
, &need_commit2
);
2280 if (need_commit1
|| need_commit2
)
2281 (void) commit(pool
);
2286 static void pool_resume(struct dm_target
*ti
)
2288 struct pool_c
*pt
= ti
->private;
2289 struct pool
*pool
= pt
->pool
;
2290 unsigned long flags
;
2292 spin_lock_irqsave(&pool
->lock
, flags
);
2293 pool
->low_water_triggered
= 0;
2294 pool
->no_free_space
= 0;
2295 __requeue_bios(pool
);
2296 spin_unlock_irqrestore(&pool
->lock
, flags
);
2298 do_waker(&pool
->waker
.work
);
2301 static void pool_postsuspend(struct dm_target
*ti
)
2303 struct pool_c
*pt
= ti
->private;
2304 struct pool
*pool
= pt
->pool
;
2306 cancel_delayed_work(&pool
->waker
);
2307 flush_workqueue(pool
->wq
);
2308 (void) commit(pool
);
2311 static int check_arg_count(unsigned argc
, unsigned args_required
)
2313 if (argc
!= args_required
) {
2314 DMWARN("Message received with %u arguments instead of %u.",
2315 argc
, args_required
);
2322 static int read_dev_id(char *arg
, dm_thin_id
*dev_id
, int warning
)
2324 if (!kstrtoull(arg
, 10, (unsigned long long *)dev_id
) &&
2325 *dev_id
<= MAX_DEV_ID
)
2329 DMWARN("Message received with invalid device id: %s", arg
);
2334 static int process_create_thin_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2339 r
= check_arg_count(argc
, 2);
2343 r
= read_dev_id(argv
[1], &dev_id
, 1);
2347 r
= dm_pool_create_thin(pool
->pmd
, dev_id
);
2349 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2357 static int process_create_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2360 dm_thin_id origin_dev_id
;
2363 r
= check_arg_count(argc
, 3);
2367 r
= read_dev_id(argv
[1], &dev_id
, 1);
2371 r
= read_dev_id(argv
[2], &origin_dev_id
, 1);
2375 r
= dm_pool_create_snap(pool
->pmd
, dev_id
, origin_dev_id
);
2377 DMWARN("Creation of new snapshot %s of device %s failed.",
2385 static int process_delete_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2390 r
= check_arg_count(argc
, 2);
2394 r
= read_dev_id(argv
[1], &dev_id
, 1);
2398 r
= dm_pool_delete_thin_device(pool
->pmd
, dev_id
);
2400 DMWARN("Deletion of thin device %s failed.", argv
[1]);
2405 static int process_set_transaction_id_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2407 dm_thin_id old_id
, new_id
;
2410 r
= check_arg_count(argc
, 3);
2414 if (kstrtoull(argv
[1], 10, (unsigned long long *)&old_id
)) {
2415 DMWARN("set_transaction_id message: Unrecognised id %s.", argv
[1]);
2419 if (kstrtoull(argv
[2], 10, (unsigned long long *)&new_id
)) {
2420 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv
[2]);
2424 r
= dm_pool_set_metadata_transaction_id(pool
->pmd
, old_id
, new_id
);
2426 DMWARN("Failed to change transaction id from %s to %s.",
2434 static int process_reserve_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2438 r
= check_arg_count(argc
, 1);
2442 (void) commit(pool
);
2444 r
= dm_pool_reserve_metadata_snap(pool
->pmd
);
2446 DMWARN("reserve_metadata_snap message failed.");
2451 static int process_release_metadata_snap_mesg(unsigned argc
, char **argv
, struct pool
*pool
)
2455 r
= check_arg_count(argc
, 1);
2459 r
= dm_pool_release_metadata_snap(pool
->pmd
);
2461 DMWARN("release_metadata_snap message failed.");
2467 * Messages supported:
2468 * create_thin <dev_id>
2469 * create_snap <dev_id> <origin_id>
2471 * trim <dev_id> <new_size_in_sectors>
2472 * set_transaction_id <current_trans_id> <new_trans_id>
2473 * reserve_metadata_snap
2474 * release_metadata_snap
2476 static int pool_message(struct dm_target
*ti
, unsigned argc
, char **argv
)
2479 struct pool_c
*pt
= ti
->private;
2480 struct pool
*pool
= pt
->pool
;
2482 if (!strcasecmp(argv
[0], "create_thin"))
2483 r
= process_create_thin_mesg(argc
, argv
, pool
);
2485 else if (!strcasecmp(argv
[0], "create_snap"))
2486 r
= process_create_snap_mesg(argc
, argv
, pool
);
2488 else if (!strcasecmp(argv
[0], "delete"))
2489 r
= process_delete_mesg(argc
, argv
, pool
);
2491 else if (!strcasecmp(argv
[0], "set_transaction_id"))
2492 r
= process_set_transaction_id_mesg(argc
, argv
, pool
);
2494 else if (!strcasecmp(argv
[0], "reserve_metadata_snap"))
2495 r
= process_reserve_metadata_snap_mesg(argc
, argv
, pool
);
2497 else if (!strcasecmp(argv
[0], "release_metadata_snap"))
2498 r
= process_release_metadata_snap_mesg(argc
, argv
, pool
);
2501 DMWARN("Unrecognised thin pool target message received: %s", argv
[0]);
2504 (void) commit(pool
);
2509 static void emit_flags(struct pool_features
*pf
, char *result
,
2510 unsigned sz
, unsigned maxlen
)
2512 unsigned count
= !pf
->zero_new_blocks
+ !pf
->discard_enabled
+
2513 !pf
->discard_passdown
+ (pf
->mode
== PM_READ_ONLY
);
2514 DMEMIT("%u ", count
);
2516 if (!pf
->zero_new_blocks
)
2517 DMEMIT("skip_block_zeroing ");
2519 if (!pf
->discard_enabled
)
2520 DMEMIT("ignore_discard ");
2522 if (!pf
->discard_passdown
)
2523 DMEMIT("no_discard_passdown ");
2525 if (pf
->mode
== PM_READ_ONLY
)
2526 DMEMIT("read_only ");
2531 * <transaction id> <used metadata sectors>/<total metadata sectors>
2532 * <used data sectors>/<total data sectors> <held metadata root>
2534 static void pool_status(struct dm_target
*ti
, status_type_t type
,
2535 unsigned status_flags
, char *result
, unsigned maxlen
)
2539 uint64_t transaction_id
;
2540 dm_block_t nr_free_blocks_data
;
2541 dm_block_t nr_free_blocks_metadata
;
2542 dm_block_t nr_blocks_data
;
2543 dm_block_t nr_blocks_metadata
;
2544 dm_block_t held_root
;
2545 char buf
[BDEVNAME_SIZE
];
2546 char buf2
[BDEVNAME_SIZE
];
2547 struct pool_c
*pt
= ti
->private;
2548 struct pool
*pool
= pt
->pool
;
2551 case STATUSTYPE_INFO
:
2552 if (get_pool_mode(pool
) == PM_FAIL
) {
2557 /* Commit to ensure statistics aren't out-of-date */
2558 if (!(status_flags
& DM_STATUS_NOFLUSH_FLAG
) && !dm_suspended(ti
))
2559 (void) commit(pool
);
2561 r
= dm_pool_get_metadata_transaction_id(pool
->pmd
, &transaction_id
);
2563 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
2564 dm_device_name(pool
->pool_md
), r
);
2568 r
= dm_pool_get_free_metadata_block_count(pool
->pmd
, &nr_free_blocks_metadata
);
2570 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
2571 dm_device_name(pool
->pool_md
), r
);
2575 r
= dm_pool_get_metadata_dev_size(pool
->pmd
, &nr_blocks_metadata
);
2577 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
2578 dm_device_name(pool
->pool_md
), r
);
2582 r
= dm_pool_get_free_block_count(pool
->pmd
, &nr_free_blocks_data
);
2584 DMERR("%s: dm_pool_get_free_block_count returned %d",
2585 dm_device_name(pool
->pool_md
), r
);
2589 r
= dm_pool_get_data_dev_size(pool
->pmd
, &nr_blocks_data
);
2591 DMERR("%s: dm_pool_get_data_dev_size returned %d",
2592 dm_device_name(pool
->pool_md
), r
);
2596 r
= dm_pool_get_metadata_snap(pool
->pmd
, &held_root
);
2598 DMERR("%s: dm_pool_get_metadata_snap returned %d",
2599 dm_device_name(pool
->pool_md
), r
);
2603 DMEMIT("%llu %llu/%llu %llu/%llu ",
2604 (unsigned long long)transaction_id
,
2605 (unsigned long long)(nr_blocks_metadata
- nr_free_blocks_metadata
),
2606 (unsigned long long)nr_blocks_metadata
,
2607 (unsigned long long)(nr_blocks_data
- nr_free_blocks_data
),
2608 (unsigned long long)nr_blocks_data
);
2611 DMEMIT("%llu ", held_root
);
2615 if (pool
->pf
.mode
== PM_READ_ONLY
)
2620 if (!pool
->pf
.discard_enabled
)
2621 DMEMIT("ignore_discard");
2622 else if (pool
->pf
.discard_passdown
)
2623 DMEMIT("discard_passdown");
2625 DMEMIT("no_discard_passdown");
2629 case STATUSTYPE_TABLE
:
2630 DMEMIT("%s %s %lu %llu ",
2631 format_dev_t(buf
, pt
->metadata_dev
->bdev
->bd_dev
),
2632 format_dev_t(buf2
, pt
->data_dev
->bdev
->bd_dev
),
2633 (unsigned long)pool
->sectors_per_block
,
2634 (unsigned long long)pt
->low_water_blocks
);
2635 emit_flags(&pt
->requested_pf
, result
, sz
, maxlen
);
2644 static int pool_iterate_devices(struct dm_target
*ti
,
2645 iterate_devices_callout_fn fn
, void *data
)
2647 struct pool_c
*pt
= ti
->private;
2649 return fn(ti
, pt
->data_dev
, 0, ti
->len
, data
);
2652 static int pool_merge(struct dm_target
*ti
, struct bvec_merge_data
*bvm
,
2653 struct bio_vec
*biovec
, int max_size
)
2655 struct pool_c
*pt
= ti
->private;
2656 struct request_queue
*q
= bdev_get_queue(pt
->data_dev
->bdev
);
2658 if (!q
->merge_bvec_fn
)
2661 bvm
->bi_bdev
= pt
->data_dev
->bdev
;
2663 return min(max_size
, q
->merge_bvec_fn(q
, bvm
, biovec
));
2666 static void set_discard_limits(struct pool_c
*pt
, struct queue_limits
*limits
)
2668 struct pool
*pool
= pt
->pool
;
2669 struct queue_limits
*data_limits
;
2671 limits
->max_discard_sectors
= pool
->sectors_per_block
;
2674 * discard_granularity is just a hint, and not enforced.
2676 if (pt
->adjusted_pf
.discard_passdown
) {
2677 data_limits
= &bdev_get_queue(pt
->data_dev
->bdev
)->limits
;
2678 limits
->discard_granularity
= data_limits
->discard_granularity
;
2680 limits
->discard_granularity
= pool
->sectors_per_block
<< SECTOR_SHIFT
;
2683 static void pool_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
2685 struct pool_c
*pt
= ti
->private;
2686 struct pool
*pool
= pt
->pool
;
2687 uint64_t io_opt_sectors
= limits
->io_opt
>> SECTOR_SHIFT
;
2690 * If the system-determined stacked limits are compatible with the
2691 * pool's blocksize (io_opt is a factor) do not override them.
2693 if (io_opt_sectors
< pool
->sectors_per_block
||
2694 do_div(io_opt_sectors
, pool
->sectors_per_block
)) {
2695 blk_limits_io_min(limits
, 0);
2696 blk_limits_io_opt(limits
, pool
->sectors_per_block
<< SECTOR_SHIFT
);
2700 * pt->adjusted_pf is a staging area for the actual features to use.
2701 * They get transferred to the live pool in bind_control_target()
2702 * called from pool_preresume().
2704 if (!pt
->adjusted_pf
.discard_enabled
) {
2706 * Must explicitly disallow stacking discard limits otherwise the
2707 * block layer will stack them if pool's data device has support.
2708 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
2709 * user to see that, so make sure to set all discard limits to 0.
2711 limits
->discard_granularity
= 0;
2715 disable_passdown_if_not_supported(pt
);
2717 set_discard_limits(pt
, limits
);
2720 static struct target_type pool_target
= {
2721 .name
= "thin-pool",
2722 .features
= DM_TARGET_SINGLETON
| DM_TARGET_ALWAYS_WRITEABLE
|
2723 DM_TARGET_IMMUTABLE
,
2724 .version
= {1, 9, 0},
2725 .module
= THIS_MODULE
,
2729 .postsuspend
= pool_postsuspend
,
2730 .preresume
= pool_preresume
,
2731 .resume
= pool_resume
,
2732 .message
= pool_message
,
2733 .status
= pool_status
,
2734 .merge
= pool_merge
,
2735 .iterate_devices
= pool_iterate_devices
,
2736 .io_hints
= pool_io_hints
,
2739 /*----------------------------------------------------------------
2740 * Thin target methods
2741 *--------------------------------------------------------------*/
2742 static void thin_dtr(struct dm_target
*ti
)
2744 struct thin_c
*tc
= ti
->private;
2746 mutex_lock(&dm_thin_pool_table
.mutex
);
2748 __pool_dec(tc
->pool
);
2749 dm_pool_close_thin_device(tc
->td
);
2750 dm_put_device(ti
, tc
->pool_dev
);
2752 dm_put_device(ti
, tc
->origin_dev
);
2755 mutex_unlock(&dm_thin_pool_table
.mutex
);
2759 * Thin target parameters:
2761 * <pool_dev> <dev_id> [origin_dev]
2763 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2764 * dev_id: the internal device identifier
2765 * origin_dev: a device external to the pool that should act as the origin
2767 * If the pool device has discards disabled, they get disabled for the thin
2770 static int thin_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
2774 struct dm_dev
*pool_dev
, *origin_dev
;
2775 struct mapped_device
*pool_md
;
2777 mutex_lock(&dm_thin_pool_table
.mutex
);
2779 if (argc
!= 2 && argc
!= 3) {
2780 ti
->error
= "Invalid argument count";
2785 tc
= ti
->private = kzalloc(sizeof(*tc
), GFP_KERNEL
);
2787 ti
->error
= "Out of memory";
2793 r
= dm_get_device(ti
, argv
[2], FMODE_READ
, &origin_dev
);
2795 ti
->error
= "Error opening origin device";
2796 goto bad_origin_dev
;
2798 tc
->origin_dev
= origin_dev
;
2801 r
= dm_get_device(ti
, argv
[0], dm_table_get_mode(ti
->table
), &pool_dev
);
2803 ti
->error
= "Error opening pool device";
2806 tc
->pool_dev
= pool_dev
;
2808 if (read_dev_id(argv
[1], (unsigned long long *)&tc
->dev_id
, 0)) {
2809 ti
->error
= "Invalid device id";
2814 pool_md
= dm_get_md(tc
->pool_dev
->bdev
->bd_dev
);
2816 ti
->error
= "Couldn't get pool mapped device";
2821 tc
->pool
= __pool_table_lookup(pool_md
);
2823 ti
->error
= "Couldn't find pool object";
2825 goto bad_pool_lookup
;
2827 __pool_inc(tc
->pool
);
2829 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
2830 ti
->error
= "Couldn't open thin device, Pool is in fail mode";
2834 r
= dm_pool_open_thin_device(tc
->pool
->pmd
, tc
->dev_id
, &tc
->td
);
2836 ti
->error
= "Couldn't open thin internal device";
2840 r
= dm_set_target_max_io_len(ti
, tc
->pool
->sectors_per_block
);
2844 ti
->num_flush_bios
= 1;
2845 ti
->flush_supported
= true;
2846 ti
->per_bio_data_size
= sizeof(struct dm_thin_endio_hook
);
2848 /* In case the pool supports discards, pass them on. */
2849 ti
->discard_zeroes_data_unsupported
= true;
2850 if (tc
->pool
->pf
.discard_enabled
) {
2851 ti
->discards_supported
= true;
2852 ti
->num_discard_bios
= 1;
2853 /* Discard bios must be split on a block boundary */
2854 ti
->split_discard_bios
= true;
2859 mutex_unlock(&dm_thin_pool_table
.mutex
);
2864 __pool_dec(tc
->pool
);
2868 dm_put_device(ti
, tc
->pool_dev
);
2871 dm_put_device(ti
, tc
->origin_dev
);
2875 mutex_unlock(&dm_thin_pool_table
.mutex
);
2880 static int thin_map(struct dm_target
*ti
, struct bio
*bio
)
2882 bio
->bi_sector
= dm_target_offset(ti
, bio
->bi_sector
);
2884 return thin_bio_map(ti
, bio
);
2887 static int thin_endio(struct dm_target
*ti
, struct bio
*bio
, int err
)
2889 unsigned long flags
;
2890 struct dm_thin_endio_hook
*h
= dm_per_bio_data(bio
, sizeof(struct dm_thin_endio_hook
));
2891 struct list_head work
;
2892 struct dm_thin_new_mapping
*m
, *tmp
;
2893 struct pool
*pool
= h
->tc
->pool
;
2895 if (h
->shared_read_entry
) {
2896 INIT_LIST_HEAD(&work
);
2897 dm_deferred_entry_dec(h
->shared_read_entry
, &work
);
2899 spin_lock_irqsave(&pool
->lock
, flags
);
2900 list_for_each_entry_safe(m
, tmp
, &work
, list
) {
2903 __maybe_add_mapping(m
);
2905 spin_unlock_irqrestore(&pool
->lock
, flags
);
2908 if (h
->all_io_entry
) {
2909 INIT_LIST_HEAD(&work
);
2910 dm_deferred_entry_dec(h
->all_io_entry
, &work
);
2911 if (!list_empty(&work
)) {
2912 spin_lock_irqsave(&pool
->lock
, flags
);
2913 list_for_each_entry_safe(m
, tmp
, &work
, list
)
2914 list_add(&m
->list
, &pool
->prepared_discards
);
2915 spin_unlock_irqrestore(&pool
->lock
, flags
);
2923 static void thin_postsuspend(struct dm_target
*ti
)
2925 if (dm_noflush_suspending(ti
))
2926 requeue_io((struct thin_c
*)ti
->private);
2930 * <nr mapped sectors> <highest mapped sector>
2932 static void thin_status(struct dm_target
*ti
, status_type_t type
,
2933 unsigned status_flags
, char *result
, unsigned maxlen
)
2937 dm_block_t mapped
, highest
;
2938 char buf
[BDEVNAME_SIZE
];
2939 struct thin_c
*tc
= ti
->private;
2941 if (get_pool_mode(tc
->pool
) == PM_FAIL
) {
2950 case STATUSTYPE_INFO
:
2951 r
= dm_thin_get_mapped_count(tc
->td
, &mapped
);
2953 DMERR("dm_thin_get_mapped_count returned %d", r
);
2957 r
= dm_thin_get_highest_mapped_block(tc
->td
, &highest
);
2959 DMERR("dm_thin_get_highest_mapped_block returned %d", r
);
2963 DMEMIT("%llu ", mapped
* tc
->pool
->sectors_per_block
);
2965 DMEMIT("%llu", ((highest
+ 1) *
2966 tc
->pool
->sectors_per_block
) - 1);
2971 case STATUSTYPE_TABLE
:
2973 format_dev_t(buf
, tc
->pool_dev
->bdev
->bd_dev
),
2974 (unsigned long) tc
->dev_id
);
2976 DMEMIT(" %s", format_dev_t(buf
, tc
->origin_dev
->bdev
->bd_dev
));
2987 static int thin_iterate_devices(struct dm_target
*ti
,
2988 iterate_devices_callout_fn fn
, void *data
)
2991 struct thin_c
*tc
= ti
->private;
2992 struct pool
*pool
= tc
->pool
;
2995 * We can't call dm_pool_get_data_dev_size() since that blocks. So
2996 * we follow a more convoluted path through to the pool's target.
2999 return 0; /* nothing is bound */
3001 blocks
= pool
->ti
->len
;
3002 (void) sector_div(blocks
, pool
->sectors_per_block
);
3004 return fn(ti
, tc
->pool_dev
, 0, pool
->sectors_per_block
* blocks
, data
);
3009 static struct target_type thin_target
= {
3011 .version
= {1, 9, 0},
3012 .module
= THIS_MODULE
,
3016 .end_io
= thin_endio
,
3017 .postsuspend
= thin_postsuspend
,
3018 .status
= thin_status
,
3019 .iterate_devices
= thin_iterate_devices
,
3022 /*----------------------------------------------------------------*/
3024 static int __init
dm_thin_init(void)
3030 r
= dm_register_target(&thin_target
);
3034 r
= dm_register_target(&pool_target
);
3036 goto bad_pool_target
;
3040 _new_mapping_cache
= KMEM_CACHE(dm_thin_new_mapping
, 0);
3041 if (!_new_mapping_cache
)
3042 goto bad_new_mapping_cache
;
3046 bad_new_mapping_cache
:
3047 dm_unregister_target(&pool_target
);
3049 dm_unregister_target(&thin_target
);
3054 static void dm_thin_exit(void)
3056 dm_unregister_target(&thin_target
);
3057 dm_unregister_target(&pool_target
);
3059 kmem_cache_destroy(_new_mapping_cache
);
3062 module_init(dm_thin_init
);
3063 module_exit(dm_thin_exit
);
3065 MODULE_DESCRIPTION(DM_NAME
" thin provisioning target");
3066 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3067 MODULE_LICENSE("GPL");