2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5 * This file is released under the GPL.
9 #include "dm-bio-list.h"
10 #include "dm-uevent.h"
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/moduleparam.h>
16 #include <linux/blkpg.h>
17 #include <linux/bio.h>
18 #include <linux/buffer_head.h>
19 #include <linux/mempool.h>
20 #include <linux/slab.h>
21 #include <linux/idr.h>
22 #include <linux/hdreg.h>
23 #include <linux/blktrace_api.h>
24 #include <trace/block.h>
26 #define DM_MSG_PREFIX "core"
28 static const char *_name
= DM_NAME
;
30 static unsigned int major
= 0;
31 static unsigned int _major
= 0;
33 static DEFINE_SPINLOCK(_minor_lock
);
36 * One of these is allocated per bio.
39 struct mapped_device
*md
;
43 unsigned long start_time
;
48 * One of these is allocated per target within a bio. Hopefully
49 * this will be simplified out one day.
57 DEFINE_TRACE(block_bio_complete
);
60 * For request-based dm.
61 * One of these is allocated per request.
63 struct dm_rq_target_io
{
64 struct mapped_device
*md
;
66 struct request
*orig
, clone
;
72 * For request-based dm.
73 * One of these is allocated per bio.
75 struct dm_rq_clone_bio_info
{
80 union map_info
*dm_get_mapinfo(struct bio
*bio
)
82 if (bio
&& bio
->bi_private
)
83 return &((struct dm_target_io
*)bio
->bi_private
)->info
;
87 #define MINOR_ALLOCED ((void *)-1)
90 * Bits for the md->flags field.
92 #define DMF_BLOCK_IO_FOR_SUSPEND 0
93 #define DMF_SUSPENDED 1
96 #define DMF_DELETING 4
97 #define DMF_NOFLUSH_SUSPENDING 5
98 #define DMF_QUEUE_IO_TO_THREAD 6
101 * Work processed by per-device workqueue.
103 struct mapped_device
{
104 struct rw_semaphore io_lock
;
105 struct mutex suspend_lock
;
112 struct request_queue
*queue
;
113 struct gendisk
*disk
;
119 * A list of ios that arrived while we were suspended.
122 wait_queue_head_t wait
;
123 struct work_struct work
;
124 struct bio_list deferred
;
125 spinlock_t deferred_lock
;
128 * Processing queue (flush/barriers)
130 struct workqueue_struct
*wq
;
133 * The current mapping.
135 struct dm_table
*map
;
138 * io objects are allocated from here.
149 wait_queue_head_t eventq
;
151 struct list_head uevent_list
;
152 spinlock_t uevent_lock
; /* Protect access to uevent_list */
155 * freeze/thaw support require holding onto a super block
157 struct super_block
*frozen_sb
;
158 struct block_device
*suspended_bdev
;
160 /* forced geometry settings */
161 struct hd_geometry geometry
;
168 static struct kmem_cache
*_io_cache
;
169 static struct kmem_cache
*_tio_cache
;
170 static struct kmem_cache
*_rq_tio_cache
;
171 static struct kmem_cache
*_rq_bio_info_cache
;
173 static int __init
local_init(void)
177 /* allocate a slab for the dm_ios */
178 _io_cache
= KMEM_CACHE(dm_io
, 0);
182 /* allocate a slab for the target ios */
183 _tio_cache
= KMEM_CACHE(dm_target_io
, 0);
185 goto out_free_io_cache
;
187 _rq_tio_cache
= KMEM_CACHE(dm_rq_target_io
, 0);
189 goto out_free_tio_cache
;
191 _rq_bio_info_cache
= KMEM_CACHE(dm_rq_clone_bio_info
, 0);
192 if (!_rq_bio_info_cache
)
193 goto out_free_rq_tio_cache
;
195 r
= dm_uevent_init();
197 goto out_free_rq_bio_info_cache
;
200 r
= register_blkdev(_major
, _name
);
202 goto out_uevent_exit
;
211 out_free_rq_bio_info_cache
:
212 kmem_cache_destroy(_rq_bio_info_cache
);
213 out_free_rq_tio_cache
:
214 kmem_cache_destroy(_rq_tio_cache
);
216 kmem_cache_destroy(_tio_cache
);
218 kmem_cache_destroy(_io_cache
);
223 static void local_exit(void)
225 kmem_cache_destroy(_rq_bio_info_cache
);
226 kmem_cache_destroy(_rq_tio_cache
);
227 kmem_cache_destroy(_tio_cache
);
228 kmem_cache_destroy(_io_cache
);
229 unregister_blkdev(_major
, _name
);
234 DMINFO("cleaned up");
237 static int (*_inits
[])(void) __initdata
= {
246 static void (*_exits
[])(void) = {
255 static int __init
dm_init(void)
257 const int count
= ARRAY_SIZE(_inits
);
261 for (i
= 0; i
< count
; i
++) {
276 static void __exit
dm_exit(void)
278 int i
= ARRAY_SIZE(_exits
);
285 * Block device functions
287 static int dm_blk_open(struct block_device
*bdev
, fmode_t mode
)
289 struct mapped_device
*md
;
291 spin_lock(&_minor_lock
);
293 md
= bdev
->bd_disk
->private_data
;
297 if (test_bit(DMF_FREEING
, &md
->flags
) ||
298 test_bit(DMF_DELETING
, &md
->flags
)) {
304 atomic_inc(&md
->open_count
);
307 spin_unlock(&_minor_lock
);
309 return md
? 0 : -ENXIO
;
312 static int dm_blk_close(struct gendisk
*disk
, fmode_t mode
)
314 struct mapped_device
*md
= disk
->private_data
;
315 atomic_dec(&md
->open_count
);
320 int dm_open_count(struct mapped_device
*md
)
322 return atomic_read(&md
->open_count
);
326 * Guarantees nothing is using the device before it's deleted.
328 int dm_lock_for_deletion(struct mapped_device
*md
)
332 spin_lock(&_minor_lock
);
334 if (dm_open_count(md
))
337 set_bit(DMF_DELETING
, &md
->flags
);
339 spin_unlock(&_minor_lock
);
344 static int dm_blk_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
346 struct mapped_device
*md
= bdev
->bd_disk
->private_data
;
348 return dm_get_geometry(md
, geo
);
351 static int dm_blk_ioctl(struct block_device
*bdev
, fmode_t mode
,
352 unsigned int cmd
, unsigned long arg
)
354 struct mapped_device
*md
= bdev
->bd_disk
->private_data
;
355 struct dm_table
*map
= dm_get_table(md
);
356 struct dm_target
*tgt
;
359 if (!map
|| !dm_table_get_size(map
))
362 /* We only support devices that have a single target */
363 if (dm_table_get_num_targets(map
) != 1)
366 tgt
= dm_table_get_target(map
, 0);
368 if (dm_suspended(md
)) {
373 if (tgt
->type
->ioctl
)
374 r
= tgt
->type
->ioctl(tgt
, cmd
, arg
);
382 static struct dm_io
*alloc_io(struct mapped_device
*md
)
384 return mempool_alloc(md
->io_pool
, GFP_NOIO
);
387 static void free_io(struct mapped_device
*md
, struct dm_io
*io
)
389 mempool_free(io
, md
->io_pool
);
392 static struct dm_target_io
*alloc_tio(struct mapped_device
*md
)
394 return mempool_alloc(md
->tio_pool
, GFP_NOIO
);
397 static void free_tio(struct mapped_device
*md
, struct dm_target_io
*tio
)
399 mempool_free(tio
, md
->tio_pool
);
402 static void start_io_acct(struct dm_io
*io
)
404 struct mapped_device
*md
= io
->md
;
407 io
->start_time
= jiffies
;
409 cpu
= part_stat_lock();
410 part_round_stats(cpu
, &dm_disk(md
)->part0
);
412 dm_disk(md
)->part0
.in_flight
= atomic_inc_return(&md
->pending
);
415 static void end_io_acct(struct dm_io
*io
)
417 struct mapped_device
*md
= io
->md
;
418 struct bio
*bio
= io
->bio
;
419 unsigned long duration
= jiffies
- io
->start_time
;
421 int rw
= bio_data_dir(bio
);
423 cpu
= part_stat_lock();
424 part_round_stats(cpu
, &dm_disk(md
)->part0
);
425 part_stat_add(cpu
, &dm_disk(md
)->part0
, ticks
[rw
], duration
);
428 dm_disk(md
)->part0
.in_flight
= pending
=
429 atomic_dec_return(&md
->pending
);
431 /* nudge anyone waiting on suspend queue */
437 * Add the bio to the list of deferred io.
439 static void queue_io(struct mapped_device
*md
, struct bio
*bio
)
441 down_write(&md
->io_lock
);
443 spin_lock_irq(&md
->deferred_lock
);
444 bio_list_add(&md
->deferred
, bio
);
445 spin_unlock_irq(&md
->deferred_lock
);
447 if (!test_and_set_bit(DMF_QUEUE_IO_TO_THREAD
, &md
->flags
))
448 queue_work(md
->wq
, &md
->work
);
450 up_write(&md
->io_lock
);
454 * Everyone (including functions in this file), should use this
455 * function to access the md->map field, and make sure they call
456 * dm_table_put() when finished.
458 struct dm_table
*dm_get_table(struct mapped_device
*md
)
462 read_lock(&md
->map_lock
);
466 read_unlock(&md
->map_lock
);
472 * Get the geometry associated with a dm device
474 int dm_get_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
)
482 * Set the geometry of a device.
484 int dm_set_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
)
486 sector_t sz
= (sector_t
)geo
->cylinders
* geo
->heads
* geo
->sectors
;
488 if (geo
->start
> sz
) {
489 DMWARN("Start sector is beyond the geometry limits.");
498 /*-----------------------------------------------------------------
500 * A more elegant soln is in the works that uses the queue
501 * merge fn, unfortunately there are a couple of changes to
502 * the block layer that I want to make for this. So in the
503 * interests of getting something for people to use I give
504 * you this clearly demarcated crap.
505 *---------------------------------------------------------------*/
507 static int __noflush_suspending(struct mapped_device
*md
)
509 return test_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
513 * Decrements the number of outstanding ios that a bio has been
514 * cloned into, completing the original io if necc.
516 static void dec_pending(struct dm_io
*io
, int error
)
521 struct mapped_device
*md
= io
->md
;
523 /* Push-back supersedes any I/O errors */
524 if (error
&& !(io
->error
> 0 && __noflush_suspending(md
)))
527 if (atomic_dec_and_test(&io
->io_count
)) {
528 if (io
->error
== DM_ENDIO_REQUEUE
) {
530 * Target requested pushing back the I/O.
532 spin_lock_irqsave(&md
->deferred_lock
, flags
);
533 if (__noflush_suspending(md
))
534 bio_list_add(&md
->deferred
, io
->bio
);
536 /* noflush suspend was interrupted. */
538 spin_unlock_irqrestore(&md
->deferred_lock
, flags
);
543 io_error
= io
->error
;
548 if (io_error
!= DM_ENDIO_REQUEUE
) {
549 trace_block_bio_complete(md
->queue
, bio
);
551 bio_endio(bio
, io_error
);
556 static void clone_endio(struct bio
*bio
, int error
)
559 struct dm_target_io
*tio
= bio
->bi_private
;
560 struct dm_io
*io
= tio
->io
;
561 struct mapped_device
*md
= tio
->io
->md
;
562 dm_endio_fn endio
= tio
->ti
->type
->end_io
;
564 if (!bio_flagged(bio
, BIO_UPTODATE
) && !error
)
568 r
= endio(tio
->ti
, bio
, error
, &tio
->info
);
569 if (r
< 0 || r
== DM_ENDIO_REQUEUE
)
571 * error and requeue request are handled
575 else if (r
== DM_ENDIO_INCOMPLETE
)
576 /* The target will handle the io */
579 DMWARN("unimplemented target endio return value: %d", r
);
585 * Store md for cleanup instead of tio which is about to get freed.
587 bio
->bi_private
= md
->bs
;
591 dec_pending(io
, error
);
594 static sector_t
max_io_len(struct mapped_device
*md
,
595 sector_t sector
, struct dm_target
*ti
)
597 sector_t offset
= sector
- ti
->begin
;
598 sector_t len
= ti
->len
- offset
;
601 * Does the target need to split even further ?
605 boundary
= ((offset
+ ti
->split_io
) & ~(ti
->split_io
- 1))
614 static void __map_bio(struct dm_target
*ti
, struct bio
*clone
,
615 struct dm_target_io
*tio
)
619 struct mapped_device
*md
;
624 BUG_ON(!clone
->bi_size
);
626 clone
->bi_end_io
= clone_endio
;
627 clone
->bi_private
= tio
;
630 * Map the clone. If r == 0 we don't need to do
631 * anything, the target has assumed ownership of
634 atomic_inc(&tio
->io
->io_count
);
635 sector
= clone
->bi_sector
;
636 r
= ti
->type
->map(ti
, clone
, &tio
->info
);
637 if (r
== DM_MAPIO_REMAPPED
) {
638 /* the bio has been remapped so dispatch it */
640 trace_block_remap(bdev_get_queue(clone
->bi_bdev
), clone
,
641 tio
->io
->bio
->bi_bdev
->bd_dev
,
642 clone
->bi_sector
, sector
);
644 generic_make_request(clone
);
645 } else if (r
< 0 || r
== DM_MAPIO_REQUEUE
) {
646 /* error the io and bail out, or requeue it if needed */
648 dec_pending(tio
->io
, r
);
650 * Store bio_set for cleanup.
652 clone
->bi_private
= md
->bs
;
656 DMWARN("unimplemented target map return value: %d", r
);
662 struct mapped_device
*md
;
663 struct dm_table
*map
;
667 sector_t sector_count
;
671 static void dm_bio_destructor(struct bio
*bio
)
673 struct bio_set
*bs
= bio
->bi_private
;
679 * Creates a little bio that is just does part of a bvec.
681 static struct bio
*split_bvec(struct bio
*bio
, sector_t sector
,
682 unsigned short idx
, unsigned int offset
,
683 unsigned int len
, struct bio_set
*bs
)
686 struct bio_vec
*bv
= bio
->bi_io_vec
+ idx
;
688 clone
= bio_alloc_bioset(GFP_NOIO
, 1, bs
);
689 clone
->bi_destructor
= dm_bio_destructor
;
690 *clone
->bi_io_vec
= *bv
;
692 clone
->bi_sector
= sector
;
693 clone
->bi_bdev
= bio
->bi_bdev
;
694 clone
->bi_rw
= bio
->bi_rw
;
696 clone
->bi_size
= to_bytes(len
);
697 clone
->bi_io_vec
->bv_offset
= offset
;
698 clone
->bi_io_vec
->bv_len
= clone
->bi_size
;
699 clone
->bi_flags
|= 1 << BIO_CLONED
;
701 if (bio_integrity(bio
)) {
702 bio_integrity_clone(clone
, bio
, GFP_NOIO
);
703 bio_integrity_trim(clone
,
704 bio_sector_offset(bio
, idx
, offset
), len
);
711 * Creates a bio that consists of range of complete bvecs.
713 static struct bio
*clone_bio(struct bio
*bio
, sector_t sector
,
714 unsigned short idx
, unsigned short bv_count
,
715 unsigned int len
, struct bio_set
*bs
)
719 clone
= bio_alloc_bioset(GFP_NOIO
, bio
->bi_max_vecs
, bs
);
720 __bio_clone(clone
, bio
);
721 clone
->bi_destructor
= dm_bio_destructor
;
722 clone
->bi_sector
= sector
;
724 clone
->bi_vcnt
= idx
+ bv_count
;
725 clone
->bi_size
= to_bytes(len
);
726 clone
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
728 if (bio_integrity(bio
)) {
729 bio_integrity_clone(clone
, bio
, GFP_NOIO
);
731 if (idx
!= bio
->bi_idx
|| clone
->bi_size
< bio
->bi_size
)
732 bio_integrity_trim(clone
,
733 bio_sector_offset(bio
, idx
, 0), len
);
739 static int __clone_and_map(struct clone_info
*ci
)
741 struct bio
*clone
, *bio
= ci
->bio
;
742 struct dm_target
*ti
;
743 sector_t len
= 0, max
;
744 struct dm_target_io
*tio
;
746 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
747 if (!dm_target_is_valid(ti
))
750 max
= max_io_len(ci
->md
, ci
->sector
, ti
);
753 * Allocate a target io object.
755 tio
= alloc_tio(ci
->md
);
758 memset(&tio
->info
, 0, sizeof(tio
->info
));
760 if (ci
->sector_count
<= max
) {
762 * Optimise for the simple case where we can do all of
763 * the remaining io with a single clone.
765 clone
= clone_bio(bio
, ci
->sector
, ci
->idx
,
766 bio
->bi_vcnt
- ci
->idx
, ci
->sector_count
,
768 __map_bio(ti
, clone
, tio
);
769 ci
->sector_count
= 0;
771 } else if (to_sector(bio
->bi_io_vec
[ci
->idx
].bv_len
) <= max
) {
773 * There are some bvecs that don't span targets.
774 * Do as many of these as possible.
777 sector_t remaining
= max
;
780 for (i
= ci
->idx
; remaining
&& (i
< bio
->bi_vcnt
); i
++) {
781 bv_len
= to_sector(bio
->bi_io_vec
[i
].bv_len
);
783 if (bv_len
> remaining
)
790 clone
= clone_bio(bio
, ci
->sector
, ci
->idx
, i
- ci
->idx
, len
,
792 __map_bio(ti
, clone
, tio
);
795 ci
->sector_count
-= len
;
800 * Handle a bvec that must be split between two or more targets.
802 struct bio_vec
*bv
= bio
->bi_io_vec
+ ci
->idx
;
803 sector_t remaining
= to_sector(bv
->bv_len
);
804 unsigned int offset
= 0;
808 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
809 if (!dm_target_is_valid(ti
))
812 max
= max_io_len(ci
->md
, ci
->sector
, ti
);
814 tio
= alloc_tio(ci
->md
);
817 memset(&tio
->info
, 0, sizeof(tio
->info
));
820 len
= min(remaining
, max
);
822 clone
= split_bvec(bio
, ci
->sector
, ci
->idx
,
823 bv
->bv_offset
+ offset
, len
,
826 __map_bio(ti
, clone
, tio
);
829 ci
->sector_count
-= len
;
830 offset
+= to_bytes(len
);
831 } while (remaining
-= len
);
840 * Split the bio into several clones and submit it to targets.
842 static void __split_and_process_bio(struct mapped_device
*md
, struct bio
*bio
)
844 struct clone_info ci
;
847 ci
.map
= dm_get_table(md
);
848 if (unlikely(!ci
.map
)) {
855 ci
.io
= alloc_io(md
);
857 atomic_set(&ci
.io
->io_count
, 1);
860 ci
.sector
= bio
->bi_sector
;
861 ci
.sector_count
= bio_sectors(bio
);
862 ci
.idx
= bio
->bi_idx
;
864 start_io_acct(ci
.io
);
865 while (ci
.sector_count
&& !error
)
866 error
= __clone_and_map(&ci
);
868 /* drop the extra reference count */
869 dec_pending(ci
.io
, error
);
870 dm_table_put(ci
.map
);
872 /*-----------------------------------------------------------------
874 *---------------------------------------------------------------*/
876 static int dm_merge_bvec(struct request_queue
*q
,
877 struct bvec_merge_data
*bvm
,
878 struct bio_vec
*biovec
)
880 struct mapped_device
*md
= q
->queuedata
;
881 struct dm_table
*map
= dm_get_table(md
);
882 struct dm_target
*ti
;
883 sector_t max_sectors
;
889 ti
= dm_table_find_target(map
, bvm
->bi_sector
);
890 if (!dm_target_is_valid(ti
))
894 * Find maximum amount of I/O that won't need splitting
896 max_sectors
= min(max_io_len(md
, bvm
->bi_sector
, ti
),
897 (sector_t
) BIO_MAX_SECTORS
);
898 max_size
= (max_sectors
<< SECTOR_SHIFT
) - bvm
->bi_size
;
903 * merge_bvec_fn() returns number of bytes
904 * it can accept at this offset
905 * max is precomputed maximal io size
907 if (max_size
&& ti
->type
->merge
)
908 max_size
= ti
->type
->merge(ti
, bvm
, biovec
, max_size
);
915 * Always allow an entire first page
917 if (max_size
<= biovec
->bv_len
&& !(bvm
->bi_size
>> SECTOR_SHIFT
))
918 max_size
= biovec
->bv_len
;
924 * The request function that just remaps the bio built up by
927 static int dm_request(struct request_queue
*q
, struct bio
*bio
)
929 int rw
= bio_data_dir(bio
);
930 struct mapped_device
*md
= q
->queuedata
;
934 * There is no use in forwarding any barrier request since we can't
935 * guarantee it is (or can be) handled by the targets correctly.
937 if (unlikely(bio_barrier(bio
))) {
938 bio_endio(bio
, -EOPNOTSUPP
);
942 down_read(&md
->io_lock
);
944 cpu
= part_stat_lock();
945 part_stat_inc(cpu
, &dm_disk(md
)->part0
, ios
[rw
]);
946 part_stat_add(cpu
, &dm_disk(md
)->part0
, sectors
[rw
], bio_sectors(bio
));
950 * If we're suspended or the thread is processing barriers
951 * we have to queue this io for later.
953 if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD
, &md
->flags
))) {
954 up_read(&md
->io_lock
);
956 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) &&
957 bio_rw(bio
) == READA
) {
967 __split_and_process_bio(md
, bio
);
968 up_read(&md
->io_lock
);
972 static void dm_unplug_all(struct request_queue
*q
)
974 struct mapped_device
*md
= q
->queuedata
;
975 struct dm_table
*map
= dm_get_table(md
);
978 dm_table_unplug_all(map
);
983 static int dm_any_congested(void *congested_data
, int bdi_bits
)
986 struct mapped_device
*md
= congested_data
;
987 struct dm_table
*map
;
989 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
990 map
= dm_get_table(md
);
992 r
= dm_table_any_congested(map
, bdi_bits
);
1000 /*-----------------------------------------------------------------
1001 * An IDR is used to keep track of allocated minor numbers.
1002 *---------------------------------------------------------------*/
1003 static DEFINE_IDR(_minor_idr
);
1005 static void free_minor(int minor
)
1007 spin_lock(&_minor_lock
);
1008 idr_remove(&_minor_idr
, minor
);
1009 spin_unlock(&_minor_lock
);
1013 * See if the device with a specific minor # is free.
1015 static int specific_minor(int minor
)
1019 if (minor
>= (1 << MINORBITS
))
1022 r
= idr_pre_get(&_minor_idr
, GFP_KERNEL
);
1026 spin_lock(&_minor_lock
);
1028 if (idr_find(&_minor_idr
, minor
)) {
1033 r
= idr_get_new_above(&_minor_idr
, MINOR_ALLOCED
, minor
, &m
);
1038 idr_remove(&_minor_idr
, m
);
1044 spin_unlock(&_minor_lock
);
1048 static int next_free_minor(int *minor
)
1052 r
= idr_pre_get(&_minor_idr
, GFP_KERNEL
);
1056 spin_lock(&_minor_lock
);
1058 r
= idr_get_new(&_minor_idr
, MINOR_ALLOCED
, &m
);
1062 if (m
>= (1 << MINORBITS
)) {
1063 idr_remove(&_minor_idr
, m
);
1071 spin_unlock(&_minor_lock
);
1075 static struct block_device_operations dm_blk_dops
;
1077 static void dm_wq_work(struct work_struct
*work
);
1080 * Allocate and initialise a blank device with a given minor.
1082 static struct mapped_device
*alloc_dev(int minor
)
1085 struct mapped_device
*md
= kzalloc(sizeof(*md
), GFP_KERNEL
);
1089 DMWARN("unable to allocate device, out of memory.");
1093 if (!try_module_get(THIS_MODULE
))
1094 goto bad_module_get
;
1096 /* get a minor number for the dev */
1097 if (minor
== DM_ANY_MINOR
)
1098 r
= next_free_minor(&minor
);
1100 r
= specific_minor(minor
);
1104 init_rwsem(&md
->io_lock
);
1105 mutex_init(&md
->suspend_lock
);
1106 spin_lock_init(&md
->deferred_lock
);
1107 rwlock_init(&md
->map_lock
);
1108 atomic_set(&md
->holders
, 1);
1109 atomic_set(&md
->open_count
, 0);
1110 atomic_set(&md
->event_nr
, 0);
1111 atomic_set(&md
->uevent_seq
, 0);
1112 INIT_LIST_HEAD(&md
->uevent_list
);
1113 spin_lock_init(&md
->uevent_lock
);
1115 md
->queue
= blk_alloc_queue(GFP_KERNEL
);
1119 md
->queue
->queuedata
= md
;
1120 md
->queue
->backing_dev_info
.congested_fn
= dm_any_congested
;
1121 md
->queue
->backing_dev_info
.congested_data
= md
;
1122 blk_queue_make_request(md
->queue
, dm_request
);
1123 blk_queue_ordered(md
->queue
, QUEUE_ORDERED_DRAIN
, NULL
);
1124 blk_queue_bounce_limit(md
->queue
, BLK_BOUNCE_ANY
);
1125 md
->queue
->unplug_fn
= dm_unplug_all
;
1126 blk_queue_merge_bvec(md
->queue
, dm_merge_bvec
);
1128 md
->io_pool
= mempool_create_slab_pool(MIN_IOS
, _io_cache
);
1132 md
->tio_pool
= mempool_create_slab_pool(MIN_IOS
, _tio_cache
);
1136 md
->bs
= bioset_create(16, 0);
1140 md
->disk
= alloc_disk(1);
1144 atomic_set(&md
->pending
, 0);
1145 init_waitqueue_head(&md
->wait
);
1146 INIT_WORK(&md
->work
, dm_wq_work
);
1147 init_waitqueue_head(&md
->eventq
);
1149 md
->disk
->major
= _major
;
1150 md
->disk
->first_minor
= minor
;
1151 md
->disk
->fops
= &dm_blk_dops
;
1152 md
->disk
->queue
= md
->queue
;
1153 md
->disk
->private_data
= md
;
1154 sprintf(md
->disk
->disk_name
, "dm-%d", minor
);
1156 format_dev_t(md
->name
, MKDEV(_major
, minor
));
1158 md
->wq
= create_singlethread_workqueue("kdmflush");
1162 /* Populate the mapping, nobody knows we exist yet */
1163 spin_lock(&_minor_lock
);
1164 old_md
= idr_replace(&_minor_idr
, md
, minor
);
1165 spin_unlock(&_minor_lock
);
1167 BUG_ON(old_md
!= MINOR_ALLOCED
);
1174 bioset_free(md
->bs
);
1176 mempool_destroy(md
->tio_pool
);
1178 mempool_destroy(md
->io_pool
);
1180 blk_cleanup_queue(md
->queue
);
1184 module_put(THIS_MODULE
);
1190 static void unlock_fs(struct mapped_device
*md
);
1192 static void free_dev(struct mapped_device
*md
)
1194 int minor
= MINOR(disk_devt(md
->disk
));
1196 if (md
->suspended_bdev
) {
1198 bdput(md
->suspended_bdev
);
1200 destroy_workqueue(md
->wq
);
1201 mempool_destroy(md
->tio_pool
);
1202 mempool_destroy(md
->io_pool
);
1203 bioset_free(md
->bs
);
1204 blk_integrity_unregister(md
->disk
);
1205 del_gendisk(md
->disk
);
1208 spin_lock(&_minor_lock
);
1209 md
->disk
->private_data
= NULL
;
1210 spin_unlock(&_minor_lock
);
1213 blk_cleanup_queue(md
->queue
);
1214 module_put(THIS_MODULE
);
1219 * Bind a table to the device.
1221 static void event_callback(void *context
)
1223 unsigned long flags
;
1225 struct mapped_device
*md
= (struct mapped_device
*) context
;
1227 spin_lock_irqsave(&md
->uevent_lock
, flags
);
1228 list_splice_init(&md
->uevent_list
, &uevents
);
1229 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
1231 dm_send_uevents(&uevents
, &disk_to_dev(md
->disk
)->kobj
);
1233 atomic_inc(&md
->event_nr
);
1234 wake_up(&md
->eventq
);
1237 static void __set_size(struct mapped_device
*md
, sector_t size
)
1239 set_capacity(md
->disk
, size
);
1241 mutex_lock(&md
->suspended_bdev
->bd_inode
->i_mutex
);
1242 i_size_write(md
->suspended_bdev
->bd_inode
, (loff_t
)size
<< SECTOR_SHIFT
);
1243 mutex_unlock(&md
->suspended_bdev
->bd_inode
->i_mutex
);
1246 static int __bind(struct mapped_device
*md
, struct dm_table
*t
)
1248 struct request_queue
*q
= md
->queue
;
1251 size
= dm_table_get_size(t
);
1254 * Wipe any geometry if the size of the table changed.
1256 if (size
!= get_capacity(md
->disk
))
1257 memset(&md
->geometry
, 0, sizeof(md
->geometry
));
1259 if (md
->suspended_bdev
)
1260 __set_size(md
, size
);
1263 dm_table_destroy(t
);
1267 dm_table_event_callback(t
, event_callback
, md
);
1269 write_lock(&md
->map_lock
);
1271 dm_table_set_restrictions(t
, q
);
1272 write_unlock(&md
->map_lock
);
1277 static void __unbind(struct mapped_device
*md
)
1279 struct dm_table
*map
= md
->map
;
1284 dm_table_event_callback(map
, NULL
, NULL
);
1285 write_lock(&md
->map_lock
);
1287 write_unlock(&md
->map_lock
);
1288 dm_table_destroy(map
);
1292 * Constructor for a new device.
1294 int dm_create(int minor
, struct mapped_device
**result
)
1296 struct mapped_device
*md
;
1298 md
= alloc_dev(minor
);
1308 static struct mapped_device
*dm_find_md(dev_t dev
)
1310 struct mapped_device
*md
;
1311 unsigned minor
= MINOR(dev
);
1313 if (MAJOR(dev
) != _major
|| minor
>= (1 << MINORBITS
))
1316 spin_lock(&_minor_lock
);
1318 md
= idr_find(&_minor_idr
, minor
);
1319 if (md
&& (md
== MINOR_ALLOCED
||
1320 (MINOR(disk_devt(dm_disk(md
))) != minor
) ||
1321 test_bit(DMF_FREEING
, &md
->flags
))) {
1327 spin_unlock(&_minor_lock
);
1332 struct mapped_device
*dm_get_md(dev_t dev
)
1334 struct mapped_device
*md
= dm_find_md(dev
);
1342 void *dm_get_mdptr(struct mapped_device
*md
)
1344 return md
->interface_ptr
;
1347 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
)
1349 md
->interface_ptr
= ptr
;
1352 void dm_get(struct mapped_device
*md
)
1354 atomic_inc(&md
->holders
);
1357 const char *dm_device_name(struct mapped_device
*md
)
1361 EXPORT_SYMBOL_GPL(dm_device_name
);
1363 void dm_put(struct mapped_device
*md
)
1365 struct dm_table
*map
;
1367 BUG_ON(test_bit(DMF_FREEING
, &md
->flags
));
1369 if (atomic_dec_and_lock(&md
->holders
, &_minor_lock
)) {
1370 map
= dm_get_table(md
);
1371 idr_replace(&_minor_idr
, MINOR_ALLOCED
,
1372 MINOR(disk_devt(dm_disk(md
))));
1373 set_bit(DMF_FREEING
, &md
->flags
);
1374 spin_unlock(&_minor_lock
);
1375 if (!dm_suspended(md
)) {
1376 dm_table_presuspend_targets(map
);
1377 dm_table_postsuspend_targets(map
);
1385 EXPORT_SYMBOL_GPL(dm_put
);
1387 static int dm_wait_for_completion(struct mapped_device
*md
, int interruptible
)
1390 DECLARE_WAITQUEUE(wait
, current
);
1392 dm_unplug_all(md
->queue
);
1394 add_wait_queue(&md
->wait
, &wait
);
1397 set_current_state(interruptible
);
1400 if (!atomic_read(&md
->pending
))
1403 if (interruptible
== TASK_INTERRUPTIBLE
&&
1404 signal_pending(current
)) {
1411 set_current_state(TASK_RUNNING
);
1413 remove_wait_queue(&md
->wait
, &wait
);
1419 * Process the deferred bios
1421 static void dm_wq_work(struct work_struct
*work
)
1423 struct mapped_device
*md
= container_of(work
, struct mapped_device
,
1427 down_write(&md
->io_lock
);
1429 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
1430 spin_lock_irq(&md
->deferred_lock
);
1431 c
= bio_list_pop(&md
->deferred
);
1432 spin_unlock_irq(&md
->deferred_lock
);
1435 clear_bit(DMF_QUEUE_IO_TO_THREAD
, &md
->flags
);
1439 up_write(&md
->io_lock
);
1441 __split_and_process_bio(md
, c
);
1443 down_write(&md
->io_lock
);
1446 up_write(&md
->io_lock
);
1449 static void dm_queue_flush(struct mapped_device
*md
)
1451 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
1452 smp_mb__after_clear_bit();
1453 queue_work(md
->wq
, &md
->work
);
1457 * Swap in a new table (destroying old one).
1459 int dm_swap_table(struct mapped_device
*md
, struct dm_table
*table
)
1463 mutex_lock(&md
->suspend_lock
);
1465 /* device must be suspended */
1466 if (!dm_suspended(md
))
1469 /* without bdev, the device size cannot be changed */
1470 if (!md
->suspended_bdev
)
1471 if (get_capacity(md
->disk
) != dm_table_get_size(table
))
1475 r
= __bind(md
, table
);
1478 mutex_unlock(&md
->suspend_lock
);
1483 * Functions to lock and unlock any filesystem running on the
1486 static int lock_fs(struct mapped_device
*md
)
1490 WARN_ON(md
->frozen_sb
);
1492 md
->frozen_sb
= freeze_bdev(md
->suspended_bdev
);
1493 if (IS_ERR(md
->frozen_sb
)) {
1494 r
= PTR_ERR(md
->frozen_sb
);
1495 md
->frozen_sb
= NULL
;
1499 set_bit(DMF_FROZEN
, &md
->flags
);
1501 /* don't bdput right now, we don't want the bdev
1502 * to go away while it is locked.
1507 static void unlock_fs(struct mapped_device
*md
)
1509 if (!test_bit(DMF_FROZEN
, &md
->flags
))
1512 thaw_bdev(md
->suspended_bdev
, md
->frozen_sb
);
1513 md
->frozen_sb
= NULL
;
1514 clear_bit(DMF_FROZEN
, &md
->flags
);
1518 * We need to be able to change a mapping table under a mounted
1519 * filesystem. For example we might want to move some data in
1520 * the background. Before the table can be swapped with
1521 * dm_bind_table, dm_suspend must be called to flush any in
1522 * flight bios and ensure that any further io gets deferred.
1524 int dm_suspend(struct mapped_device
*md
, unsigned suspend_flags
)
1526 struct dm_table
*map
= NULL
;
1528 int do_lockfs
= suspend_flags
& DM_SUSPEND_LOCKFS_FLAG
? 1 : 0;
1529 int noflush
= suspend_flags
& DM_SUSPEND_NOFLUSH_FLAG
? 1 : 0;
1531 mutex_lock(&md
->suspend_lock
);
1533 if (dm_suspended(md
)) {
1538 map
= dm_get_table(md
);
1541 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
1542 * This flag is cleared before dm_suspend returns.
1545 set_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
1547 /* This does not get reverted if there's an error later. */
1548 dm_table_presuspend_targets(map
);
1550 /* bdget() can stall if the pending I/Os are not flushed */
1552 md
->suspended_bdev
= bdget_disk(md
->disk
, 0);
1553 if (!md
->suspended_bdev
) {
1554 DMWARN("bdget failed in dm_suspend");
1560 * Flush I/O to the device. noflush supersedes do_lockfs,
1561 * because lock_fs() needs to flush I/Os.
1571 * Here we must make sure that no processes are submitting requests
1572 * to target drivers i.e. no one may be executing
1573 * __split_and_process_bio. This is called from dm_request and
1576 * To get all processes out of __split_and_process_bio in dm_request,
1577 * we take the write lock. To prevent any process from reentering
1578 * __split_and_process_bio from dm_request, we set
1579 * DMF_QUEUE_IO_TO_THREAD.
1581 * To quiesce the thread (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND
1582 * and call flush_workqueue(md->wq). flush_workqueue will wait until
1583 * dm_wq_work exits and DMF_BLOCK_IO_FOR_SUSPEND will prevent any
1584 * further calls to __split_and_process_bio from dm_wq_work.
1586 down_write(&md
->io_lock
);
1587 set_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
1588 set_bit(DMF_QUEUE_IO_TO_THREAD
, &md
->flags
);
1589 up_write(&md
->io_lock
);
1591 flush_workqueue(md
->wq
);
1594 * At this point no more requests are entering target request routines.
1595 * We call dm_wait_for_completion to wait for all existing requests
1598 r
= dm_wait_for_completion(md
, TASK_INTERRUPTIBLE
);
1600 down_write(&md
->io_lock
);
1602 clear_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
1603 up_write(&md
->io_lock
);
1605 /* were we interrupted ? */
1610 goto out
; /* pushback list is already flushed, so skip flush */
1614 * If dm_wait_for_completion returned 0, the device is completely
1615 * quiescent now. There is no request-processing activity. All new
1616 * requests are being added to md->deferred list.
1619 dm_table_postsuspend_targets(map
);
1621 set_bit(DMF_SUSPENDED
, &md
->flags
);
1624 if (r
&& md
->suspended_bdev
) {
1625 bdput(md
->suspended_bdev
);
1626 md
->suspended_bdev
= NULL
;
1632 mutex_unlock(&md
->suspend_lock
);
1636 int dm_resume(struct mapped_device
*md
)
1639 struct dm_table
*map
= NULL
;
1641 mutex_lock(&md
->suspend_lock
);
1642 if (!dm_suspended(md
))
1645 map
= dm_get_table(md
);
1646 if (!map
|| !dm_table_get_size(map
))
1649 r
= dm_table_resume_targets(map
);
1657 if (md
->suspended_bdev
) {
1658 bdput(md
->suspended_bdev
);
1659 md
->suspended_bdev
= NULL
;
1662 clear_bit(DMF_SUSPENDED
, &md
->flags
);
1664 dm_table_unplug_all(map
);
1666 dm_kobject_uevent(md
);
1672 mutex_unlock(&md
->suspend_lock
);
1677 /*-----------------------------------------------------------------
1678 * Event notification.
1679 *---------------------------------------------------------------*/
1680 void dm_kobject_uevent(struct mapped_device
*md
)
1682 kobject_uevent(&disk_to_dev(md
->disk
)->kobj
, KOBJ_CHANGE
);
1685 uint32_t dm_next_uevent_seq(struct mapped_device
*md
)
1687 return atomic_add_return(1, &md
->uevent_seq
);
1690 uint32_t dm_get_event_nr(struct mapped_device
*md
)
1692 return atomic_read(&md
->event_nr
);
1695 int dm_wait_event(struct mapped_device
*md
, int event_nr
)
1697 return wait_event_interruptible(md
->eventq
,
1698 (event_nr
!= atomic_read(&md
->event_nr
)));
1701 void dm_uevent_add(struct mapped_device
*md
, struct list_head
*elist
)
1703 unsigned long flags
;
1705 spin_lock_irqsave(&md
->uevent_lock
, flags
);
1706 list_add(elist
, &md
->uevent_list
);
1707 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
1711 * The gendisk is only valid as long as you have a reference
1714 struct gendisk
*dm_disk(struct mapped_device
*md
)
1719 struct kobject
*dm_kobject(struct mapped_device
*md
)
1725 * struct mapped_device should not be exported outside of dm.c
1726 * so use this check to verify that kobj is part of md structure
1728 struct mapped_device
*dm_get_from_kobject(struct kobject
*kobj
)
1730 struct mapped_device
*md
;
1732 md
= container_of(kobj
, struct mapped_device
, kobj
);
1733 if (&md
->kobj
!= kobj
)
1740 int dm_suspended(struct mapped_device
*md
)
1742 return test_bit(DMF_SUSPENDED
, &md
->flags
);
1745 int dm_noflush_suspending(struct dm_target
*ti
)
1747 struct mapped_device
*md
= dm_table_get_md(ti
->table
);
1748 int r
= __noflush_suspending(md
);
1754 EXPORT_SYMBOL_GPL(dm_noflush_suspending
);
1756 static struct block_device_operations dm_blk_dops
= {
1757 .open
= dm_blk_open
,
1758 .release
= dm_blk_close
,
1759 .ioctl
= dm_blk_ioctl
,
1760 .getgeo
= dm_blk_getgeo
,
1761 .owner
= THIS_MODULE
1764 EXPORT_SYMBOL(dm_get_mapinfo
);
1769 module_init(dm_init
);
1770 module_exit(dm_exit
);
1772 module_param(major
, uint
, 0);
1773 MODULE_PARM_DESC(major
, "The major number of the device mapper");
1774 MODULE_DESCRIPTION(DM_NAME
" driver");
1775 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
1776 MODULE_LICENSE("GPL");