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.
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/mutex.h>
14 #include <linux/moduleparam.h>
15 #include <linux/blkpg.h>
16 #include <linux/bio.h>
17 #include <linux/buffer_head.h>
18 #include <linux/mempool.h>
19 #include <linux/slab.h>
20 #include <linux/idr.h>
21 #include <linux/hdreg.h>
23 #include <trace/events/block.h>
25 #define DM_MSG_PREFIX "core"
28 * Cookies are numeric values sent with CHANGE and REMOVE
29 * uevents while resuming, removing or renaming the device.
31 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
32 #define DM_COOKIE_LENGTH 24
34 static const char *_name
= DM_NAME
;
36 static unsigned int major
= 0;
37 static unsigned int _major
= 0;
39 static DEFINE_SPINLOCK(_minor_lock
);
42 * One of these is allocated per bio.
45 struct mapped_device
*md
;
49 unsigned long start_time
;
50 spinlock_t endio_lock
;
55 * One of these is allocated per target within a bio. Hopefully
56 * this will be simplified out one day.
65 * For request-based dm.
66 * One of these is allocated per request.
68 struct dm_rq_target_io
{
69 struct mapped_device
*md
;
71 struct request
*orig
, clone
;
77 * For request-based dm.
78 * One of these is allocated per bio.
80 struct dm_rq_clone_bio_info
{
82 struct dm_rq_target_io
*tio
;
85 union map_info
*dm_get_mapinfo(struct bio
*bio
)
87 if (bio
&& bio
->bi_private
)
88 return &((struct dm_target_io
*)bio
->bi_private
)->info
;
92 union map_info
*dm_get_rq_mapinfo(struct request
*rq
)
94 if (rq
&& rq
->end_io_data
)
95 return &((struct dm_rq_target_io
*)rq
->end_io_data
)->info
;
98 EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo
);
100 #define MINOR_ALLOCED ((void *)-1)
103 * Bits for the md->flags field.
105 #define DMF_BLOCK_IO_FOR_SUSPEND 0
106 #define DMF_SUSPENDED 1
108 #define DMF_FREEING 3
109 #define DMF_DELETING 4
110 #define DMF_NOFLUSH_SUSPENDING 5
111 #define DMF_QUEUE_IO_TO_THREAD 6
114 * Work processed by per-device workqueue.
116 struct mapped_device
{
117 struct rw_semaphore io_lock
;
118 struct mutex suspend_lock
;
125 struct request_queue
*queue
;
126 struct gendisk
*disk
;
132 * A list of ios that arrived while we were suspended.
135 wait_queue_head_t wait
;
136 struct work_struct work
;
137 struct bio_list deferred
;
138 spinlock_t deferred_lock
;
141 * An error from the barrier request currently being processed.
146 * Processing queue (flush/barriers)
148 struct workqueue_struct
*wq
;
151 * The current mapping.
153 struct dm_table
*map
;
156 * io objects are allocated from here.
167 wait_queue_head_t eventq
;
169 struct list_head uevent_list
;
170 spinlock_t uevent_lock
; /* Protect access to uevent_list */
173 * freeze/thaw support require holding onto a super block
175 struct super_block
*frozen_sb
;
176 struct block_device
*bdev
;
178 /* forced geometry settings */
179 struct hd_geometry geometry
;
181 /* marker of flush suspend for request-based dm */
182 struct request suspend_rq
;
184 /* For saving the address of __make_request for request based dm */
185 make_request_fn
*saved_make_request_fn
;
190 /* zero-length barrier that will be cloned and submitted to targets */
191 struct bio barrier_bio
;
195 * For mempools pre-allocation at the table loading time.
197 struct dm_md_mempools
{
204 static struct kmem_cache
*_io_cache
;
205 static struct kmem_cache
*_tio_cache
;
206 static struct kmem_cache
*_rq_tio_cache
;
207 static struct kmem_cache
*_rq_bio_info_cache
;
209 static int __init
local_init(void)
213 /* allocate a slab for the dm_ios */
214 _io_cache
= KMEM_CACHE(dm_io
, 0);
218 /* allocate a slab for the target ios */
219 _tio_cache
= KMEM_CACHE(dm_target_io
, 0);
221 goto out_free_io_cache
;
223 _rq_tio_cache
= KMEM_CACHE(dm_rq_target_io
, 0);
225 goto out_free_tio_cache
;
227 _rq_bio_info_cache
= KMEM_CACHE(dm_rq_clone_bio_info
, 0);
228 if (!_rq_bio_info_cache
)
229 goto out_free_rq_tio_cache
;
231 r
= dm_uevent_init();
233 goto out_free_rq_bio_info_cache
;
236 r
= register_blkdev(_major
, _name
);
238 goto out_uevent_exit
;
247 out_free_rq_bio_info_cache
:
248 kmem_cache_destroy(_rq_bio_info_cache
);
249 out_free_rq_tio_cache
:
250 kmem_cache_destroy(_rq_tio_cache
);
252 kmem_cache_destroy(_tio_cache
);
254 kmem_cache_destroy(_io_cache
);
259 static void local_exit(void)
261 kmem_cache_destroy(_rq_bio_info_cache
);
262 kmem_cache_destroy(_rq_tio_cache
);
263 kmem_cache_destroy(_tio_cache
);
264 kmem_cache_destroy(_io_cache
);
265 unregister_blkdev(_major
, _name
);
270 DMINFO("cleaned up");
273 static int (*_inits
[])(void) __initdata
= {
282 static void (*_exits
[])(void) = {
291 static int __init
dm_init(void)
293 const int count
= ARRAY_SIZE(_inits
);
297 for (i
= 0; i
< count
; i
++) {
312 static void __exit
dm_exit(void)
314 int i
= ARRAY_SIZE(_exits
);
321 * Block device functions
323 static int dm_blk_open(struct block_device
*bdev
, fmode_t mode
)
325 struct mapped_device
*md
;
327 spin_lock(&_minor_lock
);
329 md
= bdev
->bd_disk
->private_data
;
333 if (test_bit(DMF_FREEING
, &md
->flags
) ||
334 test_bit(DMF_DELETING
, &md
->flags
)) {
340 atomic_inc(&md
->open_count
);
343 spin_unlock(&_minor_lock
);
345 return md
? 0 : -ENXIO
;
348 static int dm_blk_close(struct gendisk
*disk
, fmode_t mode
)
350 struct mapped_device
*md
= disk
->private_data
;
351 atomic_dec(&md
->open_count
);
356 int dm_open_count(struct mapped_device
*md
)
358 return atomic_read(&md
->open_count
);
362 * Guarantees nothing is using the device before it's deleted.
364 int dm_lock_for_deletion(struct mapped_device
*md
)
368 spin_lock(&_minor_lock
);
370 if (dm_open_count(md
))
373 set_bit(DMF_DELETING
, &md
->flags
);
375 spin_unlock(&_minor_lock
);
380 static int dm_blk_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
382 struct mapped_device
*md
= bdev
->bd_disk
->private_data
;
384 return dm_get_geometry(md
, geo
);
387 static int dm_blk_ioctl(struct block_device
*bdev
, fmode_t mode
,
388 unsigned int cmd
, unsigned long arg
)
390 struct mapped_device
*md
= bdev
->bd_disk
->private_data
;
391 struct dm_table
*map
= dm_get_table(md
);
392 struct dm_target
*tgt
;
395 if (!map
|| !dm_table_get_size(map
))
398 /* We only support devices that have a single target */
399 if (dm_table_get_num_targets(map
) != 1)
402 tgt
= dm_table_get_target(map
, 0);
404 if (dm_suspended(md
)) {
409 if (tgt
->type
->ioctl
)
410 r
= tgt
->type
->ioctl(tgt
, cmd
, arg
);
418 static struct dm_io
*alloc_io(struct mapped_device
*md
)
420 return mempool_alloc(md
->io_pool
, GFP_NOIO
);
423 static void free_io(struct mapped_device
*md
, struct dm_io
*io
)
425 mempool_free(io
, md
->io_pool
);
428 static void free_tio(struct mapped_device
*md
, struct dm_target_io
*tio
)
430 mempool_free(tio
, md
->tio_pool
);
433 static struct dm_rq_target_io
*alloc_rq_tio(struct mapped_device
*md
)
435 return mempool_alloc(md
->tio_pool
, GFP_ATOMIC
);
438 static void free_rq_tio(struct dm_rq_target_io
*tio
)
440 mempool_free(tio
, tio
->md
->tio_pool
);
443 static struct dm_rq_clone_bio_info
*alloc_bio_info(struct mapped_device
*md
)
445 return mempool_alloc(md
->io_pool
, GFP_ATOMIC
);
448 static void free_bio_info(struct dm_rq_clone_bio_info
*info
)
450 mempool_free(info
, info
->tio
->md
->io_pool
);
453 static void start_io_acct(struct dm_io
*io
)
455 struct mapped_device
*md
= io
->md
;
457 int rw
= bio_data_dir(io
->bio
);
459 io
->start_time
= jiffies
;
461 cpu
= part_stat_lock();
462 part_round_stats(cpu
, &dm_disk(md
)->part0
);
464 dm_disk(md
)->part0
.in_flight
[rw
] = atomic_inc_return(&md
->pending
[rw
]);
467 static void end_io_acct(struct dm_io
*io
)
469 struct mapped_device
*md
= io
->md
;
470 struct bio
*bio
= io
->bio
;
471 unsigned long duration
= jiffies
- io
->start_time
;
473 int rw
= bio_data_dir(bio
);
475 cpu
= part_stat_lock();
476 part_round_stats(cpu
, &dm_disk(md
)->part0
);
477 part_stat_add(cpu
, &dm_disk(md
)->part0
, ticks
[rw
], duration
);
481 * After this is decremented the bio must not be touched if it is
484 dm_disk(md
)->part0
.in_flight
[rw
] = pending
=
485 atomic_dec_return(&md
->pending
[rw
]);
486 pending
+= atomic_read(&md
->pending
[rw
^0x1]);
488 /* nudge anyone waiting on suspend queue */
494 * Add the bio to the list of deferred io.
496 static void queue_io(struct mapped_device
*md
, struct bio
*bio
)
498 down_write(&md
->io_lock
);
500 spin_lock_irq(&md
->deferred_lock
);
501 bio_list_add(&md
->deferred
, bio
);
502 spin_unlock_irq(&md
->deferred_lock
);
504 if (!test_and_set_bit(DMF_QUEUE_IO_TO_THREAD
, &md
->flags
))
505 queue_work(md
->wq
, &md
->work
);
507 up_write(&md
->io_lock
);
511 * Everyone (including functions in this file), should use this
512 * function to access the md->map field, and make sure they call
513 * dm_table_put() when finished.
515 struct dm_table
*dm_get_table(struct mapped_device
*md
)
520 read_lock_irqsave(&md
->map_lock
, flags
);
524 read_unlock_irqrestore(&md
->map_lock
, flags
);
530 * Get the geometry associated with a dm device
532 int dm_get_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
)
540 * Set the geometry of a device.
542 int dm_set_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
)
544 sector_t sz
= (sector_t
)geo
->cylinders
* geo
->heads
* geo
->sectors
;
546 if (geo
->start
> sz
) {
547 DMWARN("Start sector is beyond the geometry limits.");
556 /*-----------------------------------------------------------------
558 * A more elegant soln is in the works that uses the queue
559 * merge fn, unfortunately there are a couple of changes to
560 * the block layer that I want to make for this. So in the
561 * interests of getting something for people to use I give
562 * you this clearly demarcated crap.
563 *---------------------------------------------------------------*/
565 static int __noflush_suspending(struct mapped_device
*md
)
567 return test_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
571 * Decrements the number of outstanding ios that a bio has been
572 * cloned into, completing the original io if necc.
574 static void dec_pending(struct dm_io
*io
, int error
)
579 struct mapped_device
*md
= io
->md
;
581 /* Push-back supersedes any I/O errors */
582 if (unlikely(error
)) {
583 spin_lock_irqsave(&io
->endio_lock
, flags
);
584 if (!(io
->error
> 0 && __noflush_suspending(md
)))
586 spin_unlock_irqrestore(&io
->endio_lock
, flags
);
589 if (atomic_dec_and_test(&io
->io_count
)) {
590 if (io
->error
== DM_ENDIO_REQUEUE
) {
592 * Target requested pushing back the I/O.
594 spin_lock_irqsave(&md
->deferred_lock
, flags
);
595 if (__noflush_suspending(md
)) {
596 if (!bio_rw_flagged(io
->bio
, BIO_RW_BARRIER
))
597 bio_list_add_head(&md
->deferred
,
600 /* noflush suspend was interrupted. */
602 spin_unlock_irqrestore(&md
->deferred_lock
, flags
);
605 io_error
= io
->error
;
608 if (bio_rw_flagged(bio
, BIO_RW_BARRIER
)) {
610 * There can be just one barrier request so we use
611 * a per-device variable for error reporting.
612 * Note that you can't touch the bio after end_io_acct
614 if (!md
->barrier_error
&& io_error
!= -EOPNOTSUPP
)
615 md
->barrier_error
= io_error
;
620 if (io_error
!= DM_ENDIO_REQUEUE
) {
621 trace_block_bio_complete(md
->queue
, bio
);
623 bio_endio(bio
, io_error
);
631 static void clone_endio(struct bio
*bio
, int error
)
634 struct dm_target_io
*tio
= bio
->bi_private
;
635 struct dm_io
*io
= tio
->io
;
636 struct mapped_device
*md
= tio
->io
->md
;
637 dm_endio_fn endio
= tio
->ti
->type
->end_io
;
639 if (!bio_flagged(bio
, BIO_UPTODATE
) && !error
)
643 r
= endio(tio
->ti
, bio
, error
, &tio
->info
);
644 if (r
< 0 || r
== DM_ENDIO_REQUEUE
)
646 * error and requeue request are handled
650 else if (r
== DM_ENDIO_INCOMPLETE
)
651 /* The target will handle the io */
654 DMWARN("unimplemented target endio return value: %d", r
);
660 * Store md for cleanup instead of tio which is about to get freed.
662 bio
->bi_private
= md
->bs
;
666 dec_pending(io
, error
);
670 * Partial completion handling for request-based dm
672 static void end_clone_bio(struct bio
*clone
, int error
)
674 struct dm_rq_clone_bio_info
*info
= clone
->bi_private
;
675 struct dm_rq_target_io
*tio
= info
->tio
;
676 struct bio
*bio
= info
->orig
;
677 unsigned int nr_bytes
= info
->orig
->bi_size
;
683 * An error has already been detected on the request.
684 * Once error occurred, just let clone->end_io() handle
690 * Don't notice the error to the upper layer yet.
691 * The error handling decision is made by the target driver,
692 * when the request is completed.
699 * I/O for the bio successfully completed.
700 * Notice the data completion to the upper layer.
704 * bios are processed from the head of the list.
705 * So the completing bio should always be rq->bio.
706 * If it's not, something wrong is happening.
708 if (tio
->orig
->bio
!= bio
)
709 DMERR("bio completion is going in the middle of the request");
712 * Update the original request.
713 * Do not use blk_end_request() here, because it may complete
714 * the original request before the clone, and break the ordering.
716 blk_update_request(tio
->orig
, 0, nr_bytes
);
720 * Don't touch any member of the md after calling this function because
721 * the md may be freed in dm_put() at the end of this function.
722 * Or do dm_get() before calling this function and dm_put() later.
724 static void rq_completed(struct mapped_device
*md
, int run_queue
)
726 int wakeup_waiters
= 0;
727 struct request_queue
*q
= md
->queue
;
730 spin_lock_irqsave(q
->queue_lock
, flags
);
731 if (!queue_in_flight(q
))
733 spin_unlock_irqrestore(q
->queue_lock
, flags
);
735 /* nudge anyone waiting on suspend queue */
743 * dm_put() must be at the end of this function. See the comment above
748 static void free_rq_clone(struct request
*clone
)
750 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
752 blk_rq_unprep_clone(clone
);
756 static void dm_unprep_request(struct request
*rq
)
758 struct request
*clone
= rq
->special
;
761 rq
->cmd_flags
&= ~REQ_DONTPREP
;
763 free_rq_clone(clone
);
767 * Requeue the original request of a clone.
769 void dm_requeue_unmapped_request(struct request
*clone
)
771 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
772 struct mapped_device
*md
= tio
->md
;
773 struct request
*rq
= tio
->orig
;
774 struct request_queue
*q
= rq
->q
;
777 dm_unprep_request(rq
);
779 spin_lock_irqsave(q
->queue_lock
, flags
);
780 if (elv_queue_empty(q
))
782 blk_requeue_request(q
, rq
);
783 spin_unlock_irqrestore(q
->queue_lock
, flags
);
787 EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request
);
789 static void __stop_queue(struct request_queue
*q
)
794 static void stop_queue(struct request_queue
*q
)
798 spin_lock_irqsave(q
->queue_lock
, flags
);
800 spin_unlock_irqrestore(q
->queue_lock
, flags
);
803 static void __start_queue(struct request_queue
*q
)
805 if (blk_queue_stopped(q
))
809 static void start_queue(struct request_queue
*q
)
813 spin_lock_irqsave(q
->queue_lock
, flags
);
815 spin_unlock_irqrestore(q
->queue_lock
, flags
);
819 * Complete the clone and the original request.
820 * Must be called without queue lock.
822 static void dm_end_request(struct request
*clone
, int error
)
824 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
825 struct mapped_device
*md
= tio
->md
;
826 struct request
*rq
= tio
->orig
;
828 if (blk_pc_request(rq
)) {
829 rq
->errors
= clone
->errors
;
830 rq
->resid_len
= clone
->resid_len
;
834 * We are using the sense buffer of the original
836 * So setting the length of the sense data is enough.
838 rq
->sense_len
= clone
->sense_len
;
841 free_rq_clone(clone
);
843 blk_end_request_all(rq
, error
);
849 * Request completion handler for request-based dm
851 static void dm_softirq_done(struct request
*rq
)
853 struct request
*clone
= rq
->completion_data
;
854 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
855 dm_request_endio_fn rq_end_io
= tio
->ti
->type
->rq_end_io
;
856 int error
= tio
->error
;
858 if (!(rq
->cmd_flags
& REQ_FAILED
) && rq_end_io
)
859 error
= rq_end_io(tio
->ti
, clone
, error
, &tio
->info
);
862 /* The target wants to complete the I/O */
863 dm_end_request(clone
, error
);
864 else if (error
== DM_ENDIO_INCOMPLETE
)
865 /* The target will handle the I/O */
867 else if (error
== DM_ENDIO_REQUEUE
)
868 /* The target wants to requeue the I/O */
869 dm_requeue_unmapped_request(clone
);
871 DMWARN("unimplemented target endio return value: %d", error
);
877 * Complete the clone and the original request with the error status
878 * through softirq context.
880 static void dm_complete_request(struct request
*clone
, int error
)
882 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
883 struct request
*rq
= tio
->orig
;
886 rq
->completion_data
= clone
;
887 blk_complete_request(rq
);
891 * Complete the not-mapped clone and the original request with the error status
892 * through softirq context.
893 * Target's rq_end_io() function isn't called.
894 * This may be used when the target's map_rq() function fails.
896 void dm_kill_unmapped_request(struct request
*clone
, int error
)
898 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
899 struct request
*rq
= tio
->orig
;
901 rq
->cmd_flags
|= REQ_FAILED
;
902 dm_complete_request(clone
, error
);
904 EXPORT_SYMBOL_GPL(dm_kill_unmapped_request
);
907 * Called with the queue lock held
909 static void end_clone_request(struct request
*clone
, int error
)
912 * For just cleaning up the information of the queue in which
913 * the clone was dispatched.
914 * The clone is *NOT* freed actually here because it is alloced from
915 * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
917 __blk_put_request(clone
->q
, clone
);
920 * Actual request completion is done in a softirq context which doesn't
921 * hold the queue lock. Otherwise, deadlock could occur because:
922 * - another request may be submitted by the upper level driver
923 * of the stacking during the completion
924 * - the submission which requires queue lock may be done
927 dm_complete_request(clone
, error
);
930 static sector_t
max_io_len(struct mapped_device
*md
,
931 sector_t sector
, struct dm_target
*ti
)
933 sector_t offset
= sector
- ti
->begin
;
934 sector_t len
= ti
->len
- offset
;
937 * Does the target need to split even further ?
941 boundary
= ((offset
+ ti
->split_io
) & ~(ti
->split_io
- 1))
950 static void __map_bio(struct dm_target
*ti
, struct bio
*clone
,
951 struct dm_target_io
*tio
)
955 struct mapped_device
*md
;
957 clone
->bi_end_io
= clone_endio
;
958 clone
->bi_private
= tio
;
961 * Map the clone. If r == 0 we don't need to do
962 * anything, the target has assumed ownership of
965 atomic_inc(&tio
->io
->io_count
);
966 sector
= clone
->bi_sector
;
967 r
= ti
->type
->map(ti
, clone
, &tio
->info
);
968 if (r
== DM_MAPIO_REMAPPED
) {
969 /* the bio has been remapped so dispatch it */
971 trace_block_remap(bdev_get_queue(clone
->bi_bdev
), clone
,
972 tio
->io
->bio
->bi_bdev
->bd_dev
, sector
);
974 generic_make_request(clone
);
975 } else if (r
< 0 || r
== DM_MAPIO_REQUEUE
) {
976 /* error the io and bail out, or requeue it if needed */
978 dec_pending(tio
->io
, r
);
980 * Store bio_set for cleanup.
982 clone
->bi_private
= md
->bs
;
986 DMWARN("unimplemented target map return value: %d", r
);
992 struct mapped_device
*md
;
993 struct dm_table
*map
;
997 sector_t sector_count
;
1001 static void dm_bio_destructor(struct bio
*bio
)
1003 struct bio_set
*bs
= bio
->bi_private
;
1009 * Creates a little bio that is just does part of a bvec.
1011 static struct bio
*split_bvec(struct bio
*bio
, sector_t sector
,
1012 unsigned short idx
, unsigned int offset
,
1013 unsigned int len
, struct bio_set
*bs
)
1016 struct bio_vec
*bv
= bio
->bi_io_vec
+ idx
;
1018 clone
= bio_alloc_bioset(GFP_NOIO
, 1, bs
);
1019 clone
->bi_destructor
= dm_bio_destructor
;
1020 *clone
->bi_io_vec
= *bv
;
1022 clone
->bi_sector
= sector
;
1023 clone
->bi_bdev
= bio
->bi_bdev
;
1024 clone
->bi_rw
= bio
->bi_rw
& ~(1 << BIO_RW_BARRIER
);
1026 clone
->bi_size
= to_bytes(len
);
1027 clone
->bi_io_vec
->bv_offset
= offset
;
1028 clone
->bi_io_vec
->bv_len
= clone
->bi_size
;
1029 clone
->bi_flags
|= 1 << BIO_CLONED
;
1031 if (bio_integrity(bio
)) {
1032 bio_integrity_clone(clone
, bio
, GFP_NOIO
, bs
);
1033 bio_integrity_trim(clone
,
1034 bio_sector_offset(bio
, idx
, offset
), len
);
1041 * Creates a bio that consists of range of complete bvecs.
1043 static struct bio
*clone_bio(struct bio
*bio
, sector_t sector
,
1044 unsigned short idx
, unsigned short bv_count
,
1045 unsigned int len
, struct bio_set
*bs
)
1049 clone
= bio_alloc_bioset(GFP_NOIO
, bio
->bi_max_vecs
, bs
);
1050 __bio_clone(clone
, bio
);
1051 clone
->bi_rw
&= ~(1 << BIO_RW_BARRIER
);
1052 clone
->bi_destructor
= dm_bio_destructor
;
1053 clone
->bi_sector
= sector
;
1054 clone
->bi_idx
= idx
;
1055 clone
->bi_vcnt
= idx
+ bv_count
;
1056 clone
->bi_size
= to_bytes(len
);
1057 clone
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
1059 if (bio_integrity(bio
)) {
1060 bio_integrity_clone(clone
, bio
, GFP_NOIO
, bs
);
1062 if (idx
!= bio
->bi_idx
|| clone
->bi_size
< bio
->bi_size
)
1063 bio_integrity_trim(clone
,
1064 bio_sector_offset(bio
, idx
, 0), len
);
1070 static struct dm_target_io
*alloc_tio(struct clone_info
*ci
,
1071 struct dm_target
*ti
)
1073 struct dm_target_io
*tio
= mempool_alloc(ci
->md
->tio_pool
, GFP_NOIO
);
1077 memset(&tio
->info
, 0, sizeof(tio
->info
));
1082 static void __flush_target(struct clone_info
*ci
, struct dm_target
*ti
,
1085 struct dm_target_io
*tio
= alloc_tio(ci
, ti
);
1088 tio
->info
.flush_request
= flush_nr
;
1090 clone
= bio_alloc_bioset(GFP_NOIO
, 0, ci
->md
->bs
);
1091 __bio_clone(clone
, ci
->bio
);
1092 clone
->bi_destructor
= dm_bio_destructor
;
1094 __map_bio(ti
, clone
, tio
);
1097 static int __clone_and_map_empty_barrier(struct clone_info
*ci
)
1099 unsigned target_nr
= 0, flush_nr
;
1100 struct dm_target
*ti
;
1102 while ((ti
= dm_table_get_target(ci
->map
, target_nr
++)))
1103 for (flush_nr
= 0; flush_nr
< ti
->num_flush_requests
;
1105 __flush_target(ci
, ti
, flush_nr
);
1107 ci
->sector_count
= 0;
1112 static int __clone_and_map(struct clone_info
*ci
)
1114 struct bio
*clone
, *bio
= ci
->bio
;
1115 struct dm_target
*ti
;
1116 sector_t len
= 0, max
;
1117 struct dm_target_io
*tio
;
1119 if (unlikely(bio_empty_barrier(bio
)))
1120 return __clone_and_map_empty_barrier(ci
);
1122 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1123 if (!dm_target_is_valid(ti
))
1126 max
= max_io_len(ci
->md
, ci
->sector
, ti
);
1129 * Allocate a target io object.
1131 tio
= alloc_tio(ci
, ti
);
1133 if (ci
->sector_count
<= max
) {
1135 * Optimise for the simple case where we can do all of
1136 * the remaining io with a single clone.
1138 clone
= clone_bio(bio
, ci
->sector
, ci
->idx
,
1139 bio
->bi_vcnt
- ci
->idx
, ci
->sector_count
,
1141 __map_bio(ti
, clone
, tio
);
1142 ci
->sector_count
= 0;
1144 } else if (to_sector(bio
->bi_io_vec
[ci
->idx
].bv_len
) <= max
) {
1146 * There are some bvecs that don't span targets.
1147 * Do as many of these as possible.
1150 sector_t remaining
= max
;
1153 for (i
= ci
->idx
; remaining
&& (i
< bio
->bi_vcnt
); i
++) {
1154 bv_len
= to_sector(bio
->bi_io_vec
[i
].bv_len
);
1156 if (bv_len
> remaining
)
1159 remaining
-= bv_len
;
1163 clone
= clone_bio(bio
, ci
->sector
, ci
->idx
, i
- ci
->idx
, len
,
1165 __map_bio(ti
, clone
, tio
);
1168 ci
->sector_count
-= len
;
1173 * Handle a bvec that must be split between two or more targets.
1175 struct bio_vec
*bv
= bio
->bi_io_vec
+ ci
->idx
;
1176 sector_t remaining
= to_sector(bv
->bv_len
);
1177 unsigned int offset
= 0;
1181 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1182 if (!dm_target_is_valid(ti
))
1185 max
= max_io_len(ci
->md
, ci
->sector
, ti
);
1187 tio
= alloc_tio(ci
, ti
);
1190 len
= min(remaining
, max
);
1192 clone
= split_bvec(bio
, ci
->sector
, ci
->idx
,
1193 bv
->bv_offset
+ offset
, len
,
1196 __map_bio(ti
, clone
, tio
);
1199 ci
->sector_count
-= len
;
1200 offset
+= to_bytes(len
);
1201 } while (remaining
-= len
);
1210 * Split the bio into several clones and submit it to targets.
1212 static void __split_and_process_bio(struct mapped_device
*md
, struct bio
*bio
)
1214 struct clone_info ci
;
1217 ci
.map
= dm_get_table(md
);
1218 if (unlikely(!ci
.map
)) {
1219 if (!bio_rw_flagged(bio
, BIO_RW_BARRIER
))
1222 if (!md
->barrier_error
)
1223 md
->barrier_error
= -EIO
;
1229 ci
.io
= alloc_io(md
);
1231 atomic_set(&ci
.io
->io_count
, 1);
1234 spin_lock_init(&ci
.io
->endio_lock
);
1235 ci
.sector
= bio
->bi_sector
;
1236 ci
.sector_count
= bio_sectors(bio
);
1237 if (unlikely(bio_empty_barrier(bio
)))
1238 ci
.sector_count
= 1;
1239 ci
.idx
= bio
->bi_idx
;
1241 start_io_acct(ci
.io
);
1242 while (ci
.sector_count
&& !error
)
1243 error
= __clone_and_map(&ci
);
1245 /* drop the extra reference count */
1246 dec_pending(ci
.io
, error
);
1247 dm_table_put(ci
.map
);
1249 /*-----------------------------------------------------------------
1251 *---------------------------------------------------------------*/
1253 static int dm_merge_bvec(struct request_queue
*q
,
1254 struct bvec_merge_data
*bvm
,
1255 struct bio_vec
*biovec
)
1257 struct mapped_device
*md
= q
->queuedata
;
1258 struct dm_table
*map
= dm_get_table(md
);
1259 struct dm_target
*ti
;
1260 sector_t max_sectors
;
1266 ti
= dm_table_find_target(map
, bvm
->bi_sector
);
1267 if (!dm_target_is_valid(ti
))
1271 * Find maximum amount of I/O that won't need splitting
1273 max_sectors
= min(max_io_len(md
, bvm
->bi_sector
, ti
),
1274 (sector_t
) BIO_MAX_SECTORS
);
1275 max_size
= (max_sectors
<< SECTOR_SHIFT
) - bvm
->bi_size
;
1280 * merge_bvec_fn() returns number of bytes
1281 * it can accept at this offset
1282 * max is precomputed maximal io size
1284 if (max_size
&& ti
->type
->merge
)
1285 max_size
= ti
->type
->merge(ti
, bvm
, biovec
, max_size
);
1287 * If the target doesn't support merge method and some of the devices
1288 * provided their merge_bvec method (we know this by looking at
1289 * queue_max_hw_sectors), then we can't allow bios with multiple vector
1290 * entries. So always set max_size to 0, and the code below allows
1293 else if (queue_max_hw_sectors(q
) <= PAGE_SIZE
>> 9)
1302 * Always allow an entire first page
1304 if (max_size
<= biovec
->bv_len
&& !(bvm
->bi_size
>> SECTOR_SHIFT
))
1305 max_size
= biovec
->bv_len
;
1311 * The request function that just remaps the bio built up by
1314 static int _dm_request(struct request_queue
*q
, struct bio
*bio
)
1316 int rw
= bio_data_dir(bio
);
1317 struct mapped_device
*md
= q
->queuedata
;
1320 down_read(&md
->io_lock
);
1322 cpu
= part_stat_lock();
1323 part_stat_inc(cpu
, &dm_disk(md
)->part0
, ios
[rw
]);
1324 part_stat_add(cpu
, &dm_disk(md
)->part0
, sectors
[rw
], bio_sectors(bio
));
1328 * If we're suspended or the thread is processing barriers
1329 * we have to queue this io for later.
1331 if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD
, &md
->flags
)) ||
1332 unlikely(bio_rw_flagged(bio
, BIO_RW_BARRIER
))) {
1333 up_read(&md
->io_lock
);
1335 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) &&
1336 bio_rw(bio
) == READA
) {
1346 __split_and_process_bio(md
, bio
);
1347 up_read(&md
->io_lock
);
1351 static int dm_make_request(struct request_queue
*q
, struct bio
*bio
)
1353 struct mapped_device
*md
= q
->queuedata
;
1355 if (unlikely(bio_rw_flagged(bio
, BIO_RW_BARRIER
))) {
1356 bio_endio(bio
, -EOPNOTSUPP
);
1360 return md
->saved_make_request_fn(q
, bio
); /* call __make_request() */
1363 static int dm_request_based(struct mapped_device
*md
)
1365 return blk_queue_stackable(md
->queue
);
1368 static int dm_request(struct request_queue
*q
, struct bio
*bio
)
1370 struct mapped_device
*md
= q
->queuedata
;
1372 if (dm_request_based(md
))
1373 return dm_make_request(q
, bio
);
1375 return _dm_request(q
, bio
);
1378 void dm_dispatch_request(struct request
*rq
)
1382 if (blk_queue_io_stat(rq
->q
))
1383 rq
->cmd_flags
|= REQ_IO_STAT
;
1385 rq
->start_time
= jiffies
;
1386 r
= blk_insert_cloned_request(rq
->q
, rq
);
1388 dm_complete_request(rq
, r
);
1390 EXPORT_SYMBOL_GPL(dm_dispatch_request
);
1392 static void dm_rq_bio_destructor(struct bio
*bio
)
1394 struct dm_rq_clone_bio_info
*info
= bio
->bi_private
;
1395 struct mapped_device
*md
= info
->tio
->md
;
1397 free_bio_info(info
);
1398 bio_free(bio
, md
->bs
);
1401 static int dm_rq_bio_constructor(struct bio
*bio
, struct bio
*bio_orig
,
1404 struct dm_rq_target_io
*tio
= data
;
1405 struct mapped_device
*md
= tio
->md
;
1406 struct dm_rq_clone_bio_info
*info
= alloc_bio_info(md
);
1411 info
->orig
= bio_orig
;
1413 bio
->bi_end_io
= end_clone_bio
;
1414 bio
->bi_private
= info
;
1415 bio
->bi_destructor
= dm_rq_bio_destructor
;
1420 static int setup_clone(struct request
*clone
, struct request
*rq
,
1421 struct dm_rq_target_io
*tio
)
1423 int r
= blk_rq_prep_clone(clone
, rq
, tio
->md
->bs
, GFP_ATOMIC
,
1424 dm_rq_bio_constructor
, tio
);
1429 clone
->cmd
= rq
->cmd
;
1430 clone
->cmd_len
= rq
->cmd_len
;
1431 clone
->sense
= rq
->sense
;
1432 clone
->buffer
= rq
->buffer
;
1433 clone
->end_io
= end_clone_request
;
1434 clone
->end_io_data
= tio
;
1439 static int dm_rq_flush_suspending(struct mapped_device
*md
)
1441 return !md
->suspend_rq
.special
;
1445 * Called with the queue lock held.
1447 static int dm_prep_fn(struct request_queue
*q
, struct request
*rq
)
1449 struct mapped_device
*md
= q
->queuedata
;
1450 struct dm_rq_target_io
*tio
;
1451 struct request
*clone
;
1453 if (unlikely(rq
== &md
->suspend_rq
)) {
1454 if (dm_rq_flush_suspending(md
))
1457 /* The flush suspend was interrupted */
1458 return BLKPREP_KILL
;
1461 if (unlikely(rq
->special
)) {
1462 DMWARN("Already has something in rq->special.");
1463 return BLKPREP_KILL
;
1466 tio
= alloc_rq_tio(md
); /* Only one for each original request */
1469 return BLKPREP_DEFER
;
1475 memset(&tio
->info
, 0, sizeof(tio
->info
));
1477 clone
= &tio
->clone
;
1478 if (setup_clone(clone
, rq
, tio
)) {
1481 return BLKPREP_DEFER
;
1484 rq
->special
= clone
;
1485 rq
->cmd_flags
|= REQ_DONTPREP
;
1490 static void map_request(struct dm_target
*ti
, struct request
*rq
,
1491 struct mapped_device
*md
)
1494 struct request
*clone
= rq
->special
;
1495 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1498 * Hold the md reference here for the in-flight I/O.
1499 * We can't rely on the reference count by device opener,
1500 * because the device may be closed during the request completion
1501 * when all bios are completed.
1502 * See the comment in rq_completed() too.
1507 r
= ti
->type
->map_rq(ti
, clone
, &tio
->info
);
1509 case DM_MAPIO_SUBMITTED
:
1510 /* The target has taken the I/O to submit by itself later */
1512 case DM_MAPIO_REMAPPED
:
1513 /* The target has remapped the I/O so dispatch it */
1514 dm_dispatch_request(clone
);
1516 case DM_MAPIO_REQUEUE
:
1517 /* The target wants to requeue the I/O */
1518 dm_requeue_unmapped_request(clone
);
1522 DMWARN("unimplemented target map return value: %d", r
);
1526 /* The target wants to complete the I/O */
1527 dm_kill_unmapped_request(clone
, r
);
1533 * q->request_fn for request-based dm.
1534 * Called with the queue lock held.
1536 static void dm_request_fn(struct request_queue
*q
)
1538 struct mapped_device
*md
= q
->queuedata
;
1539 struct dm_table
*map
= dm_get_table(md
);
1540 struct dm_target
*ti
;
1544 * For noflush suspend, check blk_queue_stopped() to immediately
1545 * quit I/O dispatching.
1547 while (!blk_queue_plugged(q
) && !blk_queue_stopped(q
)) {
1548 rq
= blk_peek_request(q
);
1552 if (unlikely(rq
== &md
->suspend_rq
)) { /* Flush suspend maker */
1553 if (queue_in_flight(q
))
1554 /* Not quiet yet. Wait more */
1557 /* This device should be quiet now */
1559 blk_start_request(rq
);
1560 __blk_end_request_all(rq
, 0);
1565 ti
= dm_table_find_target(map
, blk_rq_pos(rq
));
1566 if (ti
->type
->busy
&& ti
->type
->busy(ti
))
1569 blk_start_request(rq
);
1570 spin_unlock(q
->queue_lock
);
1571 map_request(ti
, rq
, md
);
1572 spin_lock_irq(q
->queue_lock
);
1578 if (!elv_queue_empty(q
))
1579 /* Some requests still remain, retry later */
1588 int dm_underlying_device_busy(struct request_queue
*q
)
1590 return blk_lld_busy(q
);
1592 EXPORT_SYMBOL_GPL(dm_underlying_device_busy
);
1594 static int dm_lld_busy(struct request_queue
*q
)
1597 struct mapped_device
*md
= q
->queuedata
;
1598 struct dm_table
*map
= dm_get_table(md
);
1600 if (!map
|| test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
))
1603 r
= dm_table_any_busy_target(map
);
1610 static void dm_unplug_all(struct request_queue
*q
)
1612 struct mapped_device
*md
= q
->queuedata
;
1613 struct dm_table
*map
= dm_get_table(md
);
1616 if (dm_request_based(md
))
1617 generic_unplug_device(q
);
1619 dm_table_unplug_all(map
);
1624 static int dm_any_congested(void *congested_data
, int bdi_bits
)
1627 struct mapped_device
*md
= congested_data
;
1628 struct dm_table
*map
;
1630 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
1631 map
= dm_get_table(md
);
1634 * Request-based dm cares about only own queue for
1635 * the query about congestion status of request_queue
1637 if (dm_request_based(md
))
1638 r
= md
->queue
->backing_dev_info
.state
&
1641 r
= dm_table_any_congested(map
, bdi_bits
);
1650 /*-----------------------------------------------------------------
1651 * An IDR is used to keep track of allocated minor numbers.
1652 *---------------------------------------------------------------*/
1653 static DEFINE_IDR(_minor_idr
);
1655 static void free_minor(int minor
)
1657 spin_lock(&_minor_lock
);
1658 idr_remove(&_minor_idr
, minor
);
1659 spin_unlock(&_minor_lock
);
1663 * See if the device with a specific minor # is free.
1665 static int specific_minor(int minor
)
1669 if (minor
>= (1 << MINORBITS
))
1672 r
= idr_pre_get(&_minor_idr
, GFP_KERNEL
);
1676 spin_lock(&_minor_lock
);
1678 if (idr_find(&_minor_idr
, minor
)) {
1683 r
= idr_get_new_above(&_minor_idr
, MINOR_ALLOCED
, minor
, &m
);
1688 idr_remove(&_minor_idr
, m
);
1694 spin_unlock(&_minor_lock
);
1698 static int next_free_minor(int *minor
)
1702 r
= idr_pre_get(&_minor_idr
, GFP_KERNEL
);
1706 spin_lock(&_minor_lock
);
1708 r
= idr_get_new(&_minor_idr
, MINOR_ALLOCED
, &m
);
1712 if (m
>= (1 << MINORBITS
)) {
1713 idr_remove(&_minor_idr
, m
);
1721 spin_unlock(&_minor_lock
);
1725 static const struct block_device_operations dm_blk_dops
;
1727 static void dm_wq_work(struct work_struct
*work
);
1730 * Allocate and initialise a blank device with a given minor.
1732 static struct mapped_device
*alloc_dev(int minor
)
1735 struct mapped_device
*md
= kzalloc(sizeof(*md
), GFP_KERNEL
);
1739 DMWARN("unable to allocate device, out of memory.");
1743 if (!try_module_get(THIS_MODULE
))
1744 goto bad_module_get
;
1746 /* get a minor number for the dev */
1747 if (minor
== DM_ANY_MINOR
)
1748 r
= next_free_minor(&minor
);
1750 r
= specific_minor(minor
);
1754 init_rwsem(&md
->io_lock
);
1755 mutex_init(&md
->suspend_lock
);
1756 spin_lock_init(&md
->deferred_lock
);
1757 rwlock_init(&md
->map_lock
);
1758 atomic_set(&md
->holders
, 1);
1759 atomic_set(&md
->open_count
, 0);
1760 atomic_set(&md
->event_nr
, 0);
1761 atomic_set(&md
->uevent_seq
, 0);
1762 INIT_LIST_HEAD(&md
->uevent_list
);
1763 spin_lock_init(&md
->uevent_lock
);
1765 md
->queue
= blk_init_queue(dm_request_fn
, NULL
);
1770 * Request-based dm devices cannot be stacked on top of bio-based dm
1771 * devices. The type of this dm device has not been decided yet,
1772 * although we initialized the queue using blk_init_queue().
1773 * The type is decided at the first table loading time.
1774 * To prevent problematic device stacking, clear the queue flag
1775 * for request stacking support until then.
1777 * This queue is new, so no concurrency on the queue_flags.
1779 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE
, md
->queue
);
1780 md
->saved_make_request_fn
= md
->queue
->make_request_fn
;
1781 md
->queue
->queuedata
= md
;
1782 md
->queue
->backing_dev_info
.congested_fn
= dm_any_congested
;
1783 md
->queue
->backing_dev_info
.congested_data
= md
;
1784 blk_queue_make_request(md
->queue
, dm_request
);
1785 blk_queue_bounce_limit(md
->queue
, BLK_BOUNCE_ANY
);
1786 md
->queue
->unplug_fn
= dm_unplug_all
;
1787 blk_queue_merge_bvec(md
->queue
, dm_merge_bvec
);
1788 blk_queue_softirq_done(md
->queue
, dm_softirq_done
);
1789 blk_queue_prep_rq(md
->queue
, dm_prep_fn
);
1790 blk_queue_lld_busy(md
->queue
, dm_lld_busy
);
1792 md
->disk
= alloc_disk(1);
1796 atomic_set(&md
->pending
[0], 0);
1797 atomic_set(&md
->pending
[1], 0);
1798 init_waitqueue_head(&md
->wait
);
1799 INIT_WORK(&md
->work
, dm_wq_work
);
1800 init_waitqueue_head(&md
->eventq
);
1802 md
->disk
->major
= _major
;
1803 md
->disk
->first_minor
= minor
;
1804 md
->disk
->fops
= &dm_blk_dops
;
1805 md
->disk
->queue
= md
->queue
;
1806 md
->disk
->private_data
= md
;
1807 sprintf(md
->disk
->disk_name
, "dm-%d", minor
);
1809 format_dev_t(md
->name
, MKDEV(_major
, minor
));
1811 md
->wq
= create_singlethread_workqueue("kdmflush");
1815 md
->bdev
= bdget_disk(md
->disk
, 0);
1819 /* Populate the mapping, nobody knows we exist yet */
1820 spin_lock(&_minor_lock
);
1821 old_md
= idr_replace(&_minor_idr
, md
, minor
);
1822 spin_unlock(&_minor_lock
);
1824 BUG_ON(old_md
!= MINOR_ALLOCED
);
1829 destroy_workqueue(md
->wq
);
1831 del_gendisk(md
->disk
);
1834 blk_cleanup_queue(md
->queue
);
1838 module_put(THIS_MODULE
);
1844 static void unlock_fs(struct mapped_device
*md
);
1846 static void free_dev(struct mapped_device
*md
)
1848 int minor
= MINOR(disk_devt(md
->disk
));
1852 destroy_workqueue(md
->wq
);
1854 mempool_destroy(md
->tio_pool
);
1856 mempool_destroy(md
->io_pool
);
1858 bioset_free(md
->bs
);
1859 blk_integrity_unregister(md
->disk
);
1860 del_gendisk(md
->disk
);
1863 spin_lock(&_minor_lock
);
1864 md
->disk
->private_data
= NULL
;
1865 spin_unlock(&_minor_lock
);
1868 blk_cleanup_queue(md
->queue
);
1869 module_put(THIS_MODULE
);
1873 static void __bind_mempools(struct mapped_device
*md
, struct dm_table
*t
)
1875 struct dm_md_mempools
*p
;
1877 if (md
->io_pool
&& md
->tio_pool
&& md
->bs
)
1878 /* the md already has necessary mempools */
1881 p
= dm_table_get_md_mempools(t
);
1882 BUG_ON(!p
|| md
->io_pool
|| md
->tio_pool
|| md
->bs
);
1884 md
->io_pool
= p
->io_pool
;
1886 md
->tio_pool
= p
->tio_pool
;
1892 /* mempool bind completed, now no need any mempools in the table */
1893 dm_table_free_md_mempools(t
);
1897 * Bind a table to the device.
1899 static void event_callback(void *context
)
1901 unsigned long flags
;
1903 struct mapped_device
*md
= (struct mapped_device
*) context
;
1905 spin_lock_irqsave(&md
->uevent_lock
, flags
);
1906 list_splice_init(&md
->uevent_list
, &uevents
);
1907 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
1909 dm_send_uevents(&uevents
, &disk_to_dev(md
->disk
)->kobj
);
1911 atomic_inc(&md
->event_nr
);
1912 wake_up(&md
->eventq
);
1915 static void __set_size(struct mapped_device
*md
, sector_t size
)
1917 set_capacity(md
->disk
, size
);
1919 mutex_lock(&md
->bdev
->bd_inode
->i_mutex
);
1920 i_size_write(md
->bdev
->bd_inode
, (loff_t
)size
<< SECTOR_SHIFT
);
1921 mutex_unlock(&md
->bdev
->bd_inode
->i_mutex
);
1924 static int __bind(struct mapped_device
*md
, struct dm_table
*t
,
1925 struct queue_limits
*limits
)
1927 struct request_queue
*q
= md
->queue
;
1929 unsigned long flags
;
1931 size
= dm_table_get_size(t
);
1934 * Wipe any geometry if the size of the table changed.
1936 if (size
!= get_capacity(md
->disk
))
1937 memset(&md
->geometry
, 0, sizeof(md
->geometry
));
1939 __set_size(md
, size
);
1942 dm_table_destroy(t
);
1946 dm_table_event_callback(t
, event_callback
, md
);
1949 * The queue hasn't been stopped yet, if the old table type wasn't
1950 * for request-based during suspension. So stop it to prevent
1951 * I/O mapping before resume.
1952 * This must be done before setting the queue restrictions,
1953 * because request-based dm may be run just after the setting.
1955 if (dm_table_request_based(t
) && !blk_queue_stopped(q
))
1958 __bind_mempools(md
, t
);
1960 write_lock_irqsave(&md
->map_lock
, flags
);
1962 dm_table_set_restrictions(t
, q
, limits
);
1963 write_unlock_irqrestore(&md
->map_lock
, flags
);
1968 static void __unbind(struct mapped_device
*md
)
1970 struct dm_table
*map
= md
->map
;
1971 unsigned long flags
;
1976 dm_table_event_callback(map
, NULL
, NULL
);
1977 write_lock_irqsave(&md
->map_lock
, flags
);
1979 write_unlock_irqrestore(&md
->map_lock
, flags
);
1980 dm_table_destroy(map
);
1984 * Constructor for a new device.
1986 int dm_create(int minor
, struct mapped_device
**result
)
1988 struct mapped_device
*md
;
1990 md
= alloc_dev(minor
);
2000 static struct mapped_device
*dm_find_md(dev_t dev
)
2002 struct mapped_device
*md
;
2003 unsigned minor
= MINOR(dev
);
2005 if (MAJOR(dev
) != _major
|| minor
>= (1 << MINORBITS
))
2008 spin_lock(&_minor_lock
);
2010 md
= idr_find(&_minor_idr
, minor
);
2011 if (md
&& (md
== MINOR_ALLOCED
||
2012 (MINOR(disk_devt(dm_disk(md
))) != minor
) ||
2013 test_bit(DMF_FREEING
, &md
->flags
))) {
2019 spin_unlock(&_minor_lock
);
2024 struct mapped_device
*dm_get_md(dev_t dev
)
2026 struct mapped_device
*md
= dm_find_md(dev
);
2034 void *dm_get_mdptr(struct mapped_device
*md
)
2036 return md
->interface_ptr
;
2039 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
)
2041 md
->interface_ptr
= ptr
;
2044 void dm_get(struct mapped_device
*md
)
2046 atomic_inc(&md
->holders
);
2049 const char *dm_device_name(struct mapped_device
*md
)
2053 EXPORT_SYMBOL_GPL(dm_device_name
);
2055 void dm_put(struct mapped_device
*md
)
2057 struct dm_table
*map
;
2059 BUG_ON(test_bit(DMF_FREEING
, &md
->flags
));
2061 if (atomic_dec_and_lock(&md
->holders
, &_minor_lock
)) {
2062 map
= dm_get_table(md
);
2063 idr_replace(&_minor_idr
, MINOR_ALLOCED
,
2064 MINOR(disk_devt(dm_disk(md
))));
2065 set_bit(DMF_FREEING
, &md
->flags
);
2066 spin_unlock(&_minor_lock
);
2067 if (!dm_suspended(md
)) {
2068 dm_table_presuspend_targets(map
);
2069 dm_table_postsuspend_targets(map
);
2077 EXPORT_SYMBOL_GPL(dm_put
);
2079 static int dm_wait_for_completion(struct mapped_device
*md
, int interruptible
)
2082 DECLARE_WAITQUEUE(wait
, current
);
2083 struct request_queue
*q
= md
->queue
;
2084 unsigned long flags
;
2086 dm_unplug_all(md
->queue
);
2088 add_wait_queue(&md
->wait
, &wait
);
2091 set_current_state(interruptible
);
2094 if (dm_request_based(md
)) {
2095 spin_lock_irqsave(q
->queue_lock
, flags
);
2096 if (!queue_in_flight(q
) && blk_queue_stopped(q
)) {
2097 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2100 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2101 } else if (!atomic_read(&md
->pending
[0]) &&
2102 !atomic_read(&md
->pending
[1]))
2105 if (interruptible
== TASK_INTERRUPTIBLE
&&
2106 signal_pending(current
)) {
2113 set_current_state(TASK_RUNNING
);
2115 remove_wait_queue(&md
->wait
, &wait
);
2120 static void dm_flush(struct mapped_device
*md
)
2122 dm_wait_for_completion(md
, TASK_UNINTERRUPTIBLE
);
2124 bio_init(&md
->barrier_bio
);
2125 md
->barrier_bio
.bi_bdev
= md
->bdev
;
2126 md
->barrier_bio
.bi_rw
= WRITE_BARRIER
;
2127 __split_and_process_bio(md
, &md
->barrier_bio
);
2129 dm_wait_for_completion(md
, TASK_UNINTERRUPTIBLE
);
2132 static void process_barrier(struct mapped_device
*md
, struct bio
*bio
)
2134 md
->barrier_error
= 0;
2138 if (!bio_empty_barrier(bio
)) {
2139 __split_and_process_bio(md
, bio
);
2143 if (md
->barrier_error
!= DM_ENDIO_REQUEUE
)
2144 bio_endio(bio
, md
->barrier_error
);
2146 spin_lock_irq(&md
->deferred_lock
);
2147 bio_list_add_head(&md
->deferred
, bio
);
2148 spin_unlock_irq(&md
->deferred_lock
);
2153 * Process the deferred bios
2155 static void dm_wq_work(struct work_struct
*work
)
2157 struct mapped_device
*md
= container_of(work
, struct mapped_device
,
2161 down_write(&md
->io_lock
);
2163 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
2164 spin_lock_irq(&md
->deferred_lock
);
2165 c
= bio_list_pop(&md
->deferred
);
2166 spin_unlock_irq(&md
->deferred_lock
);
2169 clear_bit(DMF_QUEUE_IO_TO_THREAD
, &md
->flags
);
2173 up_write(&md
->io_lock
);
2175 if (dm_request_based(md
))
2176 generic_make_request(c
);
2178 if (bio_rw_flagged(c
, BIO_RW_BARRIER
))
2179 process_barrier(md
, c
);
2181 __split_and_process_bio(md
, c
);
2184 down_write(&md
->io_lock
);
2187 up_write(&md
->io_lock
);
2190 static void dm_queue_flush(struct mapped_device
*md
)
2192 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
2193 smp_mb__after_clear_bit();
2194 queue_work(md
->wq
, &md
->work
);
2198 * Swap in a new table (destroying old one).
2200 int dm_swap_table(struct mapped_device
*md
, struct dm_table
*table
)
2202 struct queue_limits limits
;
2205 mutex_lock(&md
->suspend_lock
);
2207 /* device must be suspended */
2208 if (!dm_suspended(md
))
2211 r
= dm_calculate_queue_limits(table
, &limits
);
2215 /* cannot change the device type, once a table is bound */
2217 (dm_table_get_type(md
->map
) != dm_table_get_type(table
))) {
2218 DMWARN("can't change the device type after a table is bound");
2223 r
= __bind(md
, table
, &limits
);
2226 mutex_unlock(&md
->suspend_lock
);
2230 static void dm_rq_invalidate_suspend_marker(struct mapped_device
*md
)
2232 md
->suspend_rq
.special
= (void *)0x1;
2235 static void dm_rq_abort_suspend(struct mapped_device
*md
, int noflush
)
2237 struct request_queue
*q
= md
->queue
;
2238 unsigned long flags
;
2240 spin_lock_irqsave(q
->queue_lock
, flags
);
2242 dm_rq_invalidate_suspend_marker(md
);
2244 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2247 static void dm_rq_start_suspend(struct mapped_device
*md
, int noflush
)
2249 struct request
*rq
= &md
->suspend_rq
;
2250 struct request_queue
*q
= md
->queue
;
2256 blk_insert_request(q
, rq
, 0, NULL
);
2260 static int dm_rq_suspend_available(struct mapped_device
*md
, int noflush
)
2263 struct request
*rq
= &md
->suspend_rq
;
2264 struct request_queue
*q
= md
->queue
;
2265 unsigned long flags
;
2270 /* The marker must be protected by queue lock if it is in use */
2271 spin_lock_irqsave(q
->queue_lock
, flags
);
2272 if (unlikely(rq
->ref_count
)) {
2274 * This can happen, when the previous flush suspend was
2275 * interrupted, the marker is still in the queue and
2276 * this flush suspend has been invoked, because we don't
2277 * remove the marker at the time of suspend interruption.
2278 * We have only one marker per mapped_device, so we can't
2279 * start another flush suspend while it is in use.
2281 BUG_ON(!rq
->special
); /* The marker should be invalidated */
2282 DMWARN("Invalidating the previous flush suspend is still in"
2283 " progress. Please retry later.");
2286 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2292 * Functions to lock and unlock any filesystem running on the
2295 static int lock_fs(struct mapped_device
*md
)
2299 WARN_ON(md
->frozen_sb
);
2301 md
->frozen_sb
= freeze_bdev(md
->bdev
);
2302 if (IS_ERR(md
->frozen_sb
)) {
2303 r
= PTR_ERR(md
->frozen_sb
);
2304 md
->frozen_sb
= NULL
;
2308 set_bit(DMF_FROZEN
, &md
->flags
);
2313 static void unlock_fs(struct mapped_device
*md
)
2315 if (!test_bit(DMF_FROZEN
, &md
->flags
))
2318 thaw_bdev(md
->bdev
, md
->frozen_sb
);
2319 md
->frozen_sb
= NULL
;
2320 clear_bit(DMF_FROZEN
, &md
->flags
);
2324 * We need to be able to change a mapping table under a mounted
2325 * filesystem. For example we might want to move some data in
2326 * the background. Before the table can be swapped with
2327 * dm_bind_table, dm_suspend must be called to flush any in
2328 * flight bios and ensure that any further io gets deferred.
2331 * Suspend mechanism in request-based dm.
2333 * After the suspend starts, further incoming requests are kept in
2334 * the request_queue and deferred.
2335 * Remaining requests in the request_queue at the start of suspend are flushed
2336 * if it is flush suspend.
2337 * The suspend completes when the following conditions have been satisfied,
2339 * 1. q->in_flight is 0 (which means no in_flight request)
2340 * 2. queue has been stopped (which means no request dispatching)
2345 * Noflush suspend doesn't need to dispatch remaining requests.
2346 * So stop the queue immediately. Then, wait for all in_flight requests
2347 * to be completed or requeued.
2349 * To abort noflush suspend, start the queue.
2354 * Flush suspend needs to dispatch remaining requests. So stop the queue
2355 * after the remaining requests are completed. (Requeued request must be also
2356 * re-dispatched and completed. Until then, we can't stop the queue.)
2358 * During flushing the remaining requests, further incoming requests are also
2359 * inserted to the same queue. To distinguish which requests are to be
2360 * flushed, we insert a marker request to the queue at the time of starting
2361 * flush suspend, like a barrier.
2362 * The dispatching is blocked when the marker is found on the top of the queue.
2363 * And the queue is stopped when all in_flight requests are completed, since
2364 * that means the remaining requests are completely flushed.
2365 * Then, the marker is removed from the queue.
2367 * To abort flush suspend, we also need to take care of the marker, not only
2368 * starting the queue.
2369 * We don't remove the marker forcibly from the queue since it's against
2370 * the block-layer manner. Instead, we put a invalidated mark on the marker.
2371 * When the invalidated marker is found on the top of the queue, it is
2372 * immediately removed from the queue, so it doesn't block dispatching.
2373 * Because we have only one marker per mapped_device, we can't start another
2374 * flush suspend until the invalidated marker is removed from the queue.
2375 * So fail and return with -EBUSY in such a case.
2377 int dm_suspend(struct mapped_device
*md
, unsigned suspend_flags
)
2379 struct dm_table
*map
= NULL
;
2381 int do_lockfs
= suspend_flags
& DM_SUSPEND_LOCKFS_FLAG
? 1 : 0;
2382 int noflush
= suspend_flags
& DM_SUSPEND_NOFLUSH_FLAG
? 1 : 0;
2384 mutex_lock(&md
->suspend_lock
);
2386 if (dm_suspended(md
)) {
2391 if (dm_request_based(md
) && !dm_rq_suspend_available(md
, noflush
)) {
2396 map
= dm_get_table(md
);
2399 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2400 * This flag is cleared before dm_suspend returns.
2403 set_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
2405 /* This does not get reverted if there's an error later. */
2406 dm_table_presuspend_targets(map
);
2409 * Flush I/O to the device. noflush supersedes do_lockfs,
2410 * because lock_fs() needs to flush I/Os.
2412 if (!noflush
&& do_lockfs
) {
2419 * Here we must make sure that no processes are submitting requests
2420 * to target drivers i.e. no one may be executing
2421 * __split_and_process_bio. This is called from dm_request and
2424 * To get all processes out of __split_and_process_bio in dm_request,
2425 * we take the write lock. To prevent any process from reentering
2426 * __split_and_process_bio from dm_request, we set
2427 * DMF_QUEUE_IO_TO_THREAD.
2429 * To quiesce the thread (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND
2430 * and call flush_workqueue(md->wq). flush_workqueue will wait until
2431 * dm_wq_work exits and DMF_BLOCK_IO_FOR_SUSPEND will prevent any
2432 * further calls to __split_and_process_bio from dm_wq_work.
2434 down_write(&md
->io_lock
);
2435 set_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
2436 set_bit(DMF_QUEUE_IO_TO_THREAD
, &md
->flags
);
2437 up_write(&md
->io_lock
);
2439 flush_workqueue(md
->wq
);
2441 if (dm_request_based(md
))
2442 dm_rq_start_suspend(md
, noflush
);
2445 * At this point no more requests are entering target request routines.
2446 * We call dm_wait_for_completion to wait for all existing requests
2449 r
= dm_wait_for_completion(md
, TASK_INTERRUPTIBLE
);
2451 down_write(&md
->io_lock
);
2453 clear_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
2454 up_write(&md
->io_lock
);
2456 /* were we interrupted ? */
2460 if (dm_request_based(md
))
2461 dm_rq_abort_suspend(md
, noflush
);
2464 goto out
; /* pushback list is already flushed, so skip flush */
2468 * If dm_wait_for_completion returned 0, the device is completely
2469 * quiescent now. There is no request-processing activity. All new
2470 * requests are being added to md->deferred list.
2473 dm_table_postsuspend_targets(map
);
2475 set_bit(DMF_SUSPENDED
, &md
->flags
);
2481 mutex_unlock(&md
->suspend_lock
);
2485 int dm_resume(struct mapped_device
*md
)
2488 struct dm_table
*map
= NULL
;
2490 mutex_lock(&md
->suspend_lock
);
2491 if (!dm_suspended(md
))
2494 map
= dm_get_table(md
);
2495 if (!map
|| !dm_table_get_size(map
))
2498 r
= dm_table_resume_targets(map
);
2505 * Flushing deferred I/Os must be done after targets are resumed
2506 * so that mapping of targets can work correctly.
2507 * Request-based dm is queueing the deferred I/Os in its request_queue.
2509 if (dm_request_based(md
))
2510 start_queue(md
->queue
);
2514 clear_bit(DMF_SUSPENDED
, &md
->flags
);
2516 dm_table_unplug_all(map
);
2520 mutex_unlock(&md
->suspend_lock
);
2525 /*-----------------------------------------------------------------
2526 * Event notification.
2527 *---------------------------------------------------------------*/
2528 void dm_kobject_uevent(struct mapped_device
*md
, enum kobject_action action
,
2531 char udev_cookie
[DM_COOKIE_LENGTH
];
2532 char *envp
[] = { udev_cookie
, NULL
};
2535 kobject_uevent(&disk_to_dev(md
->disk
)->kobj
, action
);
2537 snprintf(udev_cookie
, DM_COOKIE_LENGTH
, "%s=%u",
2538 DM_COOKIE_ENV_VAR_NAME
, cookie
);
2539 kobject_uevent_env(&disk_to_dev(md
->disk
)->kobj
, action
, envp
);
2543 uint32_t dm_next_uevent_seq(struct mapped_device
*md
)
2545 return atomic_add_return(1, &md
->uevent_seq
);
2548 uint32_t dm_get_event_nr(struct mapped_device
*md
)
2550 return atomic_read(&md
->event_nr
);
2553 int dm_wait_event(struct mapped_device
*md
, int event_nr
)
2555 return wait_event_interruptible(md
->eventq
,
2556 (event_nr
!= atomic_read(&md
->event_nr
)));
2559 void dm_uevent_add(struct mapped_device
*md
, struct list_head
*elist
)
2561 unsigned long flags
;
2563 spin_lock_irqsave(&md
->uevent_lock
, flags
);
2564 list_add(elist
, &md
->uevent_list
);
2565 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
2569 * The gendisk is only valid as long as you have a reference
2572 struct gendisk
*dm_disk(struct mapped_device
*md
)
2577 struct kobject
*dm_kobject(struct mapped_device
*md
)
2583 * struct mapped_device should not be exported outside of dm.c
2584 * so use this check to verify that kobj is part of md structure
2586 struct mapped_device
*dm_get_from_kobject(struct kobject
*kobj
)
2588 struct mapped_device
*md
;
2590 md
= container_of(kobj
, struct mapped_device
, kobj
);
2591 if (&md
->kobj
!= kobj
)
2594 if (test_bit(DMF_FREEING
, &md
->flags
) ||
2595 test_bit(DMF_DELETING
, &md
->flags
))
2602 int dm_suspended(struct mapped_device
*md
)
2604 return test_bit(DMF_SUSPENDED
, &md
->flags
);
2607 int dm_noflush_suspending(struct dm_target
*ti
)
2609 struct mapped_device
*md
= dm_table_get_md(ti
->table
);
2610 int r
= __noflush_suspending(md
);
2616 EXPORT_SYMBOL_GPL(dm_noflush_suspending
);
2618 struct dm_md_mempools
*dm_alloc_md_mempools(unsigned type
)
2620 struct dm_md_mempools
*pools
= kmalloc(sizeof(*pools
), GFP_KERNEL
);
2625 pools
->io_pool
= (type
== DM_TYPE_BIO_BASED
) ?
2626 mempool_create_slab_pool(MIN_IOS
, _io_cache
) :
2627 mempool_create_slab_pool(MIN_IOS
, _rq_bio_info_cache
);
2628 if (!pools
->io_pool
)
2629 goto free_pools_and_out
;
2631 pools
->tio_pool
= (type
== DM_TYPE_BIO_BASED
) ?
2632 mempool_create_slab_pool(MIN_IOS
, _tio_cache
) :
2633 mempool_create_slab_pool(MIN_IOS
, _rq_tio_cache
);
2634 if (!pools
->tio_pool
)
2635 goto free_io_pool_and_out
;
2637 pools
->bs
= (type
== DM_TYPE_BIO_BASED
) ?
2638 bioset_create(16, 0) : bioset_create(MIN_IOS
, 0);
2640 goto free_tio_pool_and_out
;
2644 free_tio_pool_and_out
:
2645 mempool_destroy(pools
->tio_pool
);
2647 free_io_pool_and_out
:
2648 mempool_destroy(pools
->io_pool
);
2656 void dm_free_md_mempools(struct dm_md_mempools
*pools
)
2662 mempool_destroy(pools
->io_pool
);
2664 if (pools
->tio_pool
)
2665 mempool_destroy(pools
->tio_pool
);
2668 bioset_free(pools
->bs
);
2673 static const struct block_device_operations dm_blk_dops
= {
2674 .open
= dm_blk_open
,
2675 .release
= dm_blk_close
,
2676 .ioctl
= dm_blk_ioctl
,
2677 .getgeo
= dm_blk_getgeo
,
2678 .owner
= THIS_MODULE
2681 EXPORT_SYMBOL(dm_get_mapinfo
);
2686 module_init(dm_init
);
2687 module_exit(dm_exit
);
2689 module_param(major
, uint
, 0);
2690 MODULE_PARM_DESC(major
, "The major number of the device mapper");
2691 MODULE_DESCRIPTION(DM_NAME
" driver");
2692 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2693 MODULE_LICENSE("GPL");