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/mempool.h>
18 #include <linux/slab.h>
19 #include <linux/idr.h>
20 #include <linux/hdreg.h>
21 #include <linux/delay.h>
22 #include <linux/wait.h>
23 #include <linux/kthread.h>
25 #include <trace/events/block.h>
27 #define DM_MSG_PREFIX "core"
31 * ratelimit state to be used in DMXXX_LIMIT().
33 DEFINE_RATELIMIT_STATE(dm_ratelimit_state
,
34 DEFAULT_RATELIMIT_INTERVAL
,
35 DEFAULT_RATELIMIT_BURST
);
36 EXPORT_SYMBOL(dm_ratelimit_state
);
40 * Cookies are numeric values sent with CHANGE and REMOVE
41 * uevents while resuming, removing or renaming the device.
43 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
44 #define DM_COOKIE_LENGTH 24
46 static const char *_name
= DM_NAME
;
48 static unsigned int major
= 0;
49 static unsigned int _major
= 0;
51 static DEFINE_IDR(_minor_idr
);
53 static DEFINE_SPINLOCK(_minor_lock
);
55 static void do_deferred_remove(struct work_struct
*w
);
57 static DECLARE_WORK(deferred_remove_work
, do_deferred_remove
);
59 static struct workqueue_struct
*deferred_remove_workqueue
;
63 * One of these is allocated per bio.
66 struct mapped_device
*md
;
70 unsigned long start_time
;
71 spinlock_t endio_lock
;
72 struct dm_stats_aux stats_aux
;
76 * For request-based dm.
77 * One of these is allocated per request.
79 struct dm_rq_target_io
{
80 struct mapped_device
*md
;
82 struct request
*orig
, *clone
;
83 struct kthread_work work
;
89 * For request-based dm - the bio clones we allocate are embedded in these
92 * We allocate these with bio_alloc_bioset, using the front_pad parameter when
93 * the bioset is created - this means the bio has to come at the end of the
96 struct dm_rq_clone_bio_info
{
98 struct dm_rq_target_io
*tio
;
102 union map_info
*dm_get_rq_mapinfo(struct request
*rq
)
104 if (rq
&& rq
->end_io_data
)
105 return &((struct dm_rq_target_io
*)rq
->end_io_data
)->info
;
108 EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo
);
110 #define MINOR_ALLOCED ((void *)-1)
113 * Bits for the md->flags field.
115 #define DMF_BLOCK_IO_FOR_SUSPEND 0
116 #define DMF_SUSPENDED 1
118 #define DMF_FREEING 3
119 #define DMF_DELETING 4
120 #define DMF_NOFLUSH_SUSPENDING 5
121 #define DMF_MERGE_IS_OPTIONAL 6
122 #define DMF_DEFERRED_REMOVE 7
123 #define DMF_SUSPENDED_INTERNALLY 8
126 * A dummy definition to make RCU happy.
127 * struct dm_table should never be dereferenced in this file.
134 * Work processed by per-device workqueue.
136 struct mapped_device
{
137 struct srcu_struct io_barrier
;
138 struct mutex suspend_lock
;
143 * The current mapping.
144 * Use dm_get_live_table{_fast} or take suspend_lock for
147 struct dm_table __rcu
*map
;
149 struct list_head table_devices
;
150 struct mutex table_devices_lock
;
154 struct request_queue
*queue
;
156 /* Protect queue and type against concurrent access. */
157 struct mutex type_lock
;
159 struct target_type
*immutable_target_type
;
161 struct gendisk
*disk
;
167 * A list of ios that arrived while we were suspended.
170 wait_queue_head_t wait
;
171 struct work_struct work
;
172 struct bio_list deferred
;
173 spinlock_t deferred_lock
;
176 * Processing queue (flush)
178 struct workqueue_struct
*wq
;
181 * io objects are allocated from here.
192 wait_queue_head_t eventq
;
194 struct list_head uevent_list
;
195 spinlock_t uevent_lock
; /* Protect access to uevent_list */
198 * freeze/thaw support require holding onto a super block
200 struct super_block
*frozen_sb
;
201 struct block_device
*bdev
;
203 /* forced geometry settings */
204 struct hd_geometry geometry
;
206 /* kobject and completion */
207 struct dm_kobject_holder kobj_holder
;
209 /* zero-length flush that will be cloned and submitted to targets */
210 struct bio flush_bio
;
212 /* the number of internal suspends */
213 unsigned internal_suspend_count
;
215 struct dm_stats stats
;
217 struct kthread_worker kworker
;
218 struct task_struct
*kworker_task
;
222 * For mempools pre-allocation at the table loading time.
224 struct dm_md_mempools
{
230 struct table_device
{
231 struct list_head list
;
233 struct dm_dev dm_dev
;
236 #define RESERVED_BIO_BASED_IOS 16
237 #define RESERVED_REQUEST_BASED_IOS 256
238 #define RESERVED_MAX_IOS 1024
239 static struct kmem_cache
*_io_cache
;
240 static struct kmem_cache
*_rq_tio_cache
;
241 static struct kmem_cache
*_rq_cache
;
244 * Bio-based DM's mempools' reserved IOs set by the user.
246 static unsigned reserved_bio_based_ios
= RESERVED_BIO_BASED_IOS
;
249 * Request-based DM's mempools' reserved IOs set by the user.
251 static unsigned reserved_rq_based_ios
= RESERVED_REQUEST_BASED_IOS
;
253 static unsigned __dm_get_module_param(unsigned *module_param
,
254 unsigned def
, unsigned max
)
256 unsigned param
= ACCESS_ONCE(*module_param
);
257 unsigned modified_param
= 0;
260 modified_param
= def
;
261 else if (param
> max
)
262 modified_param
= max
;
264 if (modified_param
) {
265 (void)cmpxchg(module_param
, param
, modified_param
);
266 param
= modified_param
;
272 unsigned dm_get_reserved_bio_based_ios(void)
274 return __dm_get_module_param(&reserved_bio_based_ios
,
275 RESERVED_BIO_BASED_IOS
, RESERVED_MAX_IOS
);
277 EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios
);
279 unsigned dm_get_reserved_rq_based_ios(void)
281 return __dm_get_module_param(&reserved_rq_based_ios
,
282 RESERVED_REQUEST_BASED_IOS
, RESERVED_MAX_IOS
);
284 EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios
);
286 static int __init
local_init(void)
290 /* allocate a slab for the dm_ios */
291 _io_cache
= KMEM_CACHE(dm_io
, 0);
295 _rq_tio_cache
= KMEM_CACHE(dm_rq_target_io
, 0);
297 goto out_free_io_cache
;
299 _rq_cache
= kmem_cache_create("dm_clone_request", sizeof(struct request
),
300 __alignof__(struct request
), 0, NULL
);
302 goto out_free_rq_tio_cache
;
304 r
= dm_uevent_init();
306 goto out_free_rq_cache
;
308 deferred_remove_workqueue
= alloc_workqueue("kdmremove", WQ_UNBOUND
, 1);
309 if (!deferred_remove_workqueue
) {
311 goto out_uevent_exit
;
315 r
= register_blkdev(_major
, _name
);
317 goto out_free_workqueue
;
325 destroy_workqueue(deferred_remove_workqueue
);
329 kmem_cache_destroy(_rq_cache
);
330 out_free_rq_tio_cache
:
331 kmem_cache_destroy(_rq_tio_cache
);
333 kmem_cache_destroy(_io_cache
);
338 static void local_exit(void)
340 flush_scheduled_work();
341 destroy_workqueue(deferred_remove_workqueue
);
343 kmem_cache_destroy(_rq_cache
);
344 kmem_cache_destroy(_rq_tio_cache
);
345 kmem_cache_destroy(_io_cache
);
346 unregister_blkdev(_major
, _name
);
351 DMINFO("cleaned up");
354 static int (*_inits
[])(void) __initdata
= {
365 static void (*_exits
[])(void) = {
376 static int __init
dm_init(void)
378 const int count
= ARRAY_SIZE(_inits
);
382 for (i
= 0; i
< count
; i
++) {
397 static void __exit
dm_exit(void)
399 int i
= ARRAY_SIZE(_exits
);
405 * Should be empty by this point.
407 idr_destroy(&_minor_idr
);
411 * Block device functions
413 int dm_deleting_md(struct mapped_device
*md
)
415 return test_bit(DMF_DELETING
, &md
->flags
);
418 static int dm_blk_open(struct block_device
*bdev
, fmode_t mode
)
420 struct mapped_device
*md
;
422 spin_lock(&_minor_lock
);
424 md
= bdev
->bd_disk
->private_data
;
428 if (test_bit(DMF_FREEING
, &md
->flags
) ||
429 dm_deleting_md(md
)) {
435 atomic_inc(&md
->open_count
);
437 spin_unlock(&_minor_lock
);
439 return md
? 0 : -ENXIO
;
442 static void dm_blk_close(struct gendisk
*disk
, fmode_t mode
)
444 struct mapped_device
*md
;
446 spin_lock(&_minor_lock
);
448 md
= disk
->private_data
;
452 if (atomic_dec_and_test(&md
->open_count
) &&
453 (test_bit(DMF_DEFERRED_REMOVE
, &md
->flags
)))
454 queue_work(deferred_remove_workqueue
, &deferred_remove_work
);
458 spin_unlock(&_minor_lock
);
461 int dm_open_count(struct mapped_device
*md
)
463 return atomic_read(&md
->open_count
);
467 * Guarantees nothing is using the device before it's deleted.
469 int dm_lock_for_deletion(struct mapped_device
*md
, bool mark_deferred
, bool only_deferred
)
473 spin_lock(&_minor_lock
);
475 if (dm_open_count(md
)) {
478 set_bit(DMF_DEFERRED_REMOVE
, &md
->flags
);
479 } else if (only_deferred
&& !test_bit(DMF_DEFERRED_REMOVE
, &md
->flags
))
482 set_bit(DMF_DELETING
, &md
->flags
);
484 spin_unlock(&_minor_lock
);
489 int dm_cancel_deferred_remove(struct mapped_device
*md
)
493 spin_lock(&_minor_lock
);
495 if (test_bit(DMF_DELETING
, &md
->flags
))
498 clear_bit(DMF_DEFERRED_REMOVE
, &md
->flags
);
500 spin_unlock(&_minor_lock
);
505 static void do_deferred_remove(struct work_struct
*w
)
507 dm_deferred_remove();
510 sector_t
dm_get_size(struct mapped_device
*md
)
512 return get_capacity(md
->disk
);
515 struct request_queue
*dm_get_md_queue(struct mapped_device
*md
)
520 struct dm_stats
*dm_get_stats(struct mapped_device
*md
)
525 static int dm_blk_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
527 struct mapped_device
*md
= bdev
->bd_disk
->private_data
;
529 return dm_get_geometry(md
, geo
);
532 static int dm_blk_ioctl(struct block_device
*bdev
, fmode_t mode
,
533 unsigned int cmd
, unsigned long arg
)
535 struct mapped_device
*md
= bdev
->bd_disk
->private_data
;
537 struct dm_table
*map
;
538 struct dm_target
*tgt
;
542 map
= dm_get_live_table(md
, &srcu_idx
);
544 if (!map
|| !dm_table_get_size(map
))
547 /* We only support devices that have a single target */
548 if (dm_table_get_num_targets(map
) != 1)
551 tgt
= dm_table_get_target(map
, 0);
552 if (!tgt
->type
->ioctl
)
555 if (dm_suspended_md(md
)) {
560 r
= tgt
->type
->ioctl(tgt
, cmd
, arg
);
563 dm_put_live_table(md
, srcu_idx
);
565 if (r
== -ENOTCONN
) {
573 static struct dm_io
*alloc_io(struct mapped_device
*md
)
575 return mempool_alloc(md
->io_pool
, GFP_NOIO
);
578 static void free_io(struct mapped_device
*md
, struct dm_io
*io
)
580 mempool_free(io
, md
->io_pool
);
583 static void free_tio(struct mapped_device
*md
, struct dm_target_io
*tio
)
585 bio_put(&tio
->clone
);
588 static struct dm_rq_target_io
*alloc_rq_tio(struct mapped_device
*md
,
591 return mempool_alloc(md
->io_pool
, gfp_mask
);
594 static void free_rq_tio(struct dm_rq_target_io
*tio
)
596 mempool_free(tio
, tio
->md
->io_pool
);
599 static struct request
*alloc_clone_request(struct mapped_device
*md
,
602 return mempool_alloc(md
->rq_pool
, gfp_mask
);
605 static void free_clone_request(struct mapped_device
*md
, struct request
*rq
)
607 mempool_free(rq
, md
->rq_pool
);
610 static int md_in_flight(struct mapped_device
*md
)
612 return atomic_read(&md
->pending
[READ
]) +
613 atomic_read(&md
->pending
[WRITE
]);
616 static void start_io_acct(struct dm_io
*io
)
618 struct mapped_device
*md
= io
->md
;
619 struct bio
*bio
= io
->bio
;
621 int rw
= bio_data_dir(bio
);
623 io
->start_time
= jiffies
;
625 cpu
= part_stat_lock();
626 part_round_stats(cpu
, &dm_disk(md
)->part0
);
628 atomic_set(&dm_disk(md
)->part0
.in_flight
[rw
],
629 atomic_inc_return(&md
->pending
[rw
]));
631 if (unlikely(dm_stats_used(&md
->stats
)))
632 dm_stats_account_io(&md
->stats
, bio
->bi_rw
, bio
->bi_iter
.bi_sector
,
633 bio_sectors(bio
), false, 0, &io
->stats_aux
);
636 static void end_io_acct(struct dm_io
*io
)
638 struct mapped_device
*md
= io
->md
;
639 struct bio
*bio
= io
->bio
;
640 unsigned long duration
= jiffies
- io
->start_time
;
642 int rw
= bio_data_dir(bio
);
644 generic_end_io_acct(rw
, &dm_disk(md
)->part0
, io
->start_time
);
646 if (unlikely(dm_stats_used(&md
->stats
)))
647 dm_stats_account_io(&md
->stats
, bio
->bi_rw
, bio
->bi_iter
.bi_sector
,
648 bio_sectors(bio
), true, duration
, &io
->stats_aux
);
651 * After this is decremented the bio must not be touched if it is
654 pending
= atomic_dec_return(&md
->pending
[rw
]);
655 atomic_set(&dm_disk(md
)->part0
.in_flight
[rw
], pending
);
656 pending
+= atomic_read(&md
->pending
[rw
^0x1]);
658 /* nudge anyone waiting on suspend queue */
664 * Add the bio to the list of deferred io.
666 static void queue_io(struct mapped_device
*md
, struct bio
*bio
)
670 spin_lock_irqsave(&md
->deferred_lock
, flags
);
671 bio_list_add(&md
->deferred
, bio
);
672 spin_unlock_irqrestore(&md
->deferred_lock
, flags
);
673 queue_work(md
->wq
, &md
->work
);
677 * Everyone (including functions in this file), should use this
678 * function to access the md->map field, and make sure they call
679 * dm_put_live_table() when finished.
681 struct dm_table
*dm_get_live_table(struct mapped_device
*md
, int *srcu_idx
) __acquires(md
->io_barrier
)
683 *srcu_idx
= srcu_read_lock(&md
->io_barrier
);
685 return srcu_dereference(md
->map
, &md
->io_barrier
);
688 void dm_put_live_table(struct mapped_device
*md
, int srcu_idx
) __releases(md
->io_barrier
)
690 srcu_read_unlock(&md
->io_barrier
, srcu_idx
);
693 void dm_sync_table(struct mapped_device
*md
)
695 synchronize_srcu(&md
->io_barrier
);
696 synchronize_rcu_expedited();
700 * A fast alternative to dm_get_live_table/dm_put_live_table.
701 * The caller must not block between these two functions.
703 static struct dm_table
*dm_get_live_table_fast(struct mapped_device
*md
) __acquires(RCU
)
706 return rcu_dereference(md
->map
);
709 static void dm_put_live_table_fast(struct mapped_device
*md
) __releases(RCU
)
715 * Open a table device so we can use it as a map destination.
717 static int open_table_device(struct table_device
*td
, dev_t dev
,
718 struct mapped_device
*md
)
720 static char *_claim_ptr
= "I belong to device-mapper";
721 struct block_device
*bdev
;
725 BUG_ON(td
->dm_dev
.bdev
);
727 bdev
= blkdev_get_by_dev(dev
, td
->dm_dev
.mode
| FMODE_EXCL
, _claim_ptr
);
729 return PTR_ERR(bdev
);
731 r
= bd_link_disk_holder(bdev
, dm_disk(md
));
733 blkdev_put(bdev
, td
->dm_dev
.mode
| FMODE_EXCL
);
737 td
->dm_dev
.bdev
= bdev
;
742 * Close a table device that we've been using.
744 static void close_table_device(struct table_device
*td
, struct mapped_device
*md
)
746 if (!td
->dm_dev
.bdev
)
749 bd_unlink_disk_holder(td
->dm_dev
.bdev
, dm_disk(md
));
750 blkdev_put(td
->dm_dev
.bdev
, td
->dm_dev
.mode
| FMODE_EXCL
);
751 td
->dm_dev
.bdev
= NULL
;
754 static struct table_device
*find_table_device(struct list_head
*l
, dev_t dev
,
756 struct table_device
*td
;
758 list_for_each_entry(td
, l
, list
)
759 if (td
->dm_dev
.bdev
->bd_dev
== dev
&& td
->dm_dev
.mode
== mode
)
765 int dm_get_table_device(struct mapped_device
*md
, dev_t dev
, fmode_t mode
,
766 struct dm_dev
**result
) {
768 struct table_device
*td
;
770 mutex_lock(&md
->table_devices_lock
);
771 td
= find_table_device(&md
->table_devices
, dev
, mode
);
773 td
= kmalloc(sizeof(*td
), GFP_KERNEL
);
775 mutex_unlock(&md
->table_devices_lock
);
779 td
->dm_dev
.mode
= mode
;
780 td
->dm_dev
.bdev
= NULL
;
782 if ((r
= open_table_device(td
, dev
, md
))) {
783 mutex_unlock(&md
->table_devices_lock
);
788 format_dev_t(td
->dm_dev
.name
, dev
);
790 atomic_set(&td
->count
, 0);
791 list_add(&td
->list
, &md
->table_devices
);
793 atomic_inc(&td
->count
);
794 mutex_unlock(&md
->table_devices_lock
);
796 *result
= &td
->dm_dev
;
799 EXPORT_SYMBOL_GPL(dm_get_table_device
);
801 void dm_put_table_device(struct mapped_device
*md
, struct dm_dev
*d
)
803 struct table_device
*td
= container_of(d
, struct table_device
, dm_dev
);
805 mutex_lock(&md
->table_devices_lock
);
806 if (atomic_dec_and_test(&td
->count
)) {
807 close_table_device(td
, md
);
811 mutex_unlock(&md
->table_devices_lock
);
813 EXPORT_SYMBOL(dm_put_table_device
);
815 static void free_table_devices(struct list_head
*devices
)
817 struct list_head
*tmp
, *next
;
819 list_for_each_safe(tmp
, next
, devices
) {
820 struct table_device
*td
= list_entry(tmp
, struct table_device
, list
);
822 DMWARN("dm_destroy: %s still exists with %d references",
823 td
->dm_dev
.name
, atomic_read(&td
->count
));
829 * Get the geometry associated with a dm device
831 int dm_get_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
)
839 * Set the geometry of a device.
841 int dm_set_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
)
843 sector_t sz
= (sector_t
)geo
->cylinders
* geo
->heads
* geo
->sectors
;
845 if (geo
->start
> sz
) {
846 DMWARN("Start sector is beyond the geometry limits.");
855 /*-----------------------------------------------------------------
857 * A more elegant soln is in the works that uses the queue
858 * merge fn, unfortunately there are a couple of changes to
859 * the block layer that I want to make for this. So in the
860 * interests of getting something for people to use I give
861 * you this clearly demarcated crap.
862 *---------------------------------------------------------------*/
864 static int __noflush_suspending(struct mapped_device
*md
)
866 return test_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
870 * Decrements the number of outstanding ios that a bio has been
871 * cloned into, completing the original io if necc.
873 static void dec_pending(struct dm_io
*io
, int error
)
878 struct mapped_device
*md
= io
->md
;
880 /* Push-back supersedes any I/O errors */
881 if (unlikely(error
)) {
882 spin_lock_irqsave(&io
->endio_lock
, flags
);
883 if (!(io
->error
> 0 && __noflush_suspending(md
)))
885 spin_unlock_irqrestore(&io
->endio_lock
, flags
);
888 if (atomic_dec_and_test(&io
->io_count
)) {
889 if (io
->error
== DM_ENDIO_REQUEUE
) {
891 * Target requested pushing back the I/O.
893 spin_lock_irqsave(&md
->deferred_lock
, flags
);
894 if (__noflush_suspending(md
))
895 bio_list_add_head(&md
->deferred
, io
->bio
);
897 /* noflush suspend was interrupted. */
899 spin_unlock_irqrestore(&md
->deferred_lock
, flags
);
902 io_error
= io
->error
;
907 if (io_error
== DM_ENDIO_REQUEUE
)
910 if ((bio
->bi_rw
& REQ_FLUSH
) && bio
->bi_iter
.bi_size
) {
912 * Preflush done for flush with data, reissue
915 bio
->bi_rw
&= ~REQ_FLUSH
;
918 /* done with normal IO or empty flush */
919 trace_block_bio_complete(md
->queue
, bio
, io_error
);
920 bio_endio(bio
, io_error
);
925 static void disable_write_same(struct mapped_device
*md
)
927 struct queue_limits
*limits
= dm_get_queue_limits(md
);
929 /* device doesn't really support WRITE SAME, disable it */
930 limits
->max_write_same_sectors
= 0;
933 static void clone_endio(struct bio
*bio
, int error
)
936 struct dm_target_io
*tio
= container_of(bio
, struct dm_target_io
, clone
);
937 struct dm_io
*io
= tio
->io
;
938 struct mapped_device
*md
= tio
->io
->md
;
939 dm_endio_fn endio
= tio
->ti
->type
->end_io
;
941 if (!bio_flagged(bio
, BIO_UPTODATE
) && !error
)
945 r
= endio(tio
->ti
, bio
, error
);
946 if (r
< 0 || r
== DM_ENDIO_REQUEUE
)
948 * error and requeue request are handled
952 else if (r
== DM_ENDIO_INCOMPLETE
)
953 /* The target will handle the io */
956 DMWARN("unimplemented target endio return value: %d", r
);
961 if (unlikely(r
== -EREMOTEIO
&& (bio
->bi_rw
& REQ_WRITE_SAME
) &&
962 !bdev_get_queue(bio
->bi_bdev
)->limits
.max_write_same_sectors
))
963 disable_write_same(md
);
966 dec_pending(io
, error
);
970 * Partial completion handling for request-based dm
972 static void end_clone_bio(struct bio
*clone
, int error
)
974 struct dm_rq_clone_bio_info
*info
=
975 container_of(clone
, struct dm_rq_clone_bio_info
, clone
);
976 struct dm_rq_target_io
*tio
= info
->tio
;
977 struct bio
*bio
= info
->orig
;
978 unsigned int nr_bytes
= info
->orig
->bi_iter
.bi_size
;
984 * An error has already been detected on the request.
985 * Once error occurred, just let clone->end_io() handle
991 * Don't notice the error to the upper layer yet.
992 * The error handling decision is made by the target driver,
993 * when the request is completed.
1000 * I/O for the bio successfully completed.
1001 * Notice the data completion to the upper layer.
1005 * bios are processed from the head of the list.
1006 * So the completing bio should always be rq->bio.
1007 * If it's not, something wrong is happening.
1009 if (tio
->orig
->bio
!= bio
)
1010 DMERR("bio completion is going in the middle of the request");
1013 * Update the original request.
1014 * Do not use blk_end_request() here, because it may complete
1015 * the original request before the clone, and break the ordering.
1017 blk_update_request(tio
->orig
, 0, nr_bytes
);
1021 * Don't touch any member of the md after calling this function because
1022 * the md may be freed in dm_put() at the end of this function.
1023 * Or do dm_get() before calling this function and dm_put() later.
1025 static void rq_completed(struct mapped_device
*md
, int rw
, bool run_queue
)
1027 int nr_requests_pending
;
1029 atomic_dec(&md
->pending
[rw
]);
1031 /* nudge anyone waiting on suspend queue */
1032 nr_requests_pending
= md_in_flight(md
);
1033 if (!nr_requests_pending
)
1037 * Run this off this callpath, as drivers could invoke end_io while
1038 * inside their request_fn (and holding the queue lock). Calling
1039 * back into ->request_fn() could deadlock attempting to grab the
1043 if (!nr_requests_pending
||
1044 (nr_requests_pending
>= md
->queue
->nr_congestion_on
))
1045 blk_run_queue_async(md
->queue
);
1049 * dm_put() must be at the end of this function. See the comment above
1054 static void free_rq_clone(struct request
*clone
)
1056 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1058 blk_rq_unprep_clone(clone
);
1059 if (clone
->q
&& clone
->q
->mq_ops
)
1060 tio
->ti
->type
->release_clone_rq(clone
);
1062 free_clone_request(tio
->md
, clone
);
1067 * Complete the clone and the original request.
1068 * Must be called without clone's queue lock held,
1069 * see end_clone_request() for more details.
1071 static void dm_end_request(struct request
*clone
, int error
)
1073 int rw
= rq_data_dir(clone
);
1074 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1075 struct mapped_device
*md
= tio
->md
;
1076 struct request
*rq
= tio
->orig
;
1078 if (rq
->cmd_type
== REQ_TYPE_BLOCK_PC
) {
1079 rq
->errors
= clone
->errors
;
1080 rq
->resid_len
= clone
->resid_len
;
1084 * We are using the sense buffer of the original
1086 * So setting the length of the sense data is enough.
1088 rq
->sense_len
= clone
->sense_len
;
1091 free_rq_clone(clone
);
1092 blk_end_request_all(rq
, error
);
1093 rq_completed(md
, rw
, true);
1096 static void dm_unprep_request(struct request
*rq
)
1098 struct dm_rq_target_io
*tio
= rq
->special
;
1099 struct request
*clone
= tio
->clone
;
1102 rq
->cmd_flags
&= ~REQ_DONTPREP
;
1105 free_rq_clone(clone
);
1109 * Requeue the original request of a clone.
1111 static void dm_requeue_unmapped_original_request(struct mapped_device
*md
,
1114 int rw
= rq_data_dir(rq
);
1115 struct request_queue
*q
= rq
->q
;
1116 unsigned long flags
;
1118 dm_unprep_request(rq
);
1120 spin_lock_irqsave(q
->queue_lock
, flags
);
1121 blk_requeue_request(q
, rq
);
1122 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1124 rq_completed(md
, rw
, false);
1127 static void dm_requeue_unmapped_request(struct request
*clone
)
1129 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1131 dm_requeue_unmapped_original_request(tio
->md
, tio
->orig
);
1134 static void __stop_queue(struct request_queue
*q
)
1139 static void stop_queue(struct request_queue
*q
)
1141 unsigned long flags
;
1143 spin_lock_irqsave(q
->queue_lock
, flags
);
1145 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1148 static void __start_queue(struct request_queue
*q
)
1150 if (blk_queue_stopped(q
))
1154 static void start_queue(struct request_queue
*q
)
1156 unsigned long flags
;
1158 spin_lock_irqsave(q
->queue_lock
, flags
);
1160 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1163 static void dm_done(struct request
*clone
, int error
, bool mapped
)
1166 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1167 dm_request_endio_fn rq_end_io
= NULL
;
1170 rq_end_io
= tio
->ti
->type
->rq_end_io
;
1172 if (mapped
&& rq_end_io
)
1173 r
= rq_end_io(tio
->ti
, clone
, error
, &tio
->info
);
1176 if (unlikely(r
== -EREMOTEIO
&& (clone
->cmd_flags
& REQ_WRITE_SAME
) &&
1177 !clone
->q
->limits
.max_write_same_sectors
))
1178 disable_write_same(tio
->md
);
1181 /* The target wants to complete the I/O */
1182 dm_end_request(clone
, r
);
1183 else if (r
== DM_ENDIO_INCOMPLETE
)
1184 /* The target will handle the I/O */
1186 else if (r
== DM_ENDIO_REQUEUE
)
1187 /* The target wants to requeue the I/O */
1188 dm_requeue_unmapped_request(clone
);
1190 DMWARN("unimplemented target endio return value: %d", r
);
1196 * Request completion handler for request-based dm
1198 static void dm_softirq_done(struct request
*rq
)
1201 struct dm_rq_target_io
*tio
= rq
->special
;
1202 struct request
*clone
= tio
->clone
;
1205 blk_end_request_all(rq
, tio
->error
);
1206 rq_completed(tio
->md
, rq_data_dir(rq
), false);
1211 if (rq
->cmd_flags
& REQ_FAILED
)
1214 dm_done(clone
, tio
->error
, mapped
);
1218 * Complete the clone and the original request with the error status
1219 * through softirq context.
1221 static void dm_complete_request(struct request
*rq
, int error
)
1223 struct dm_rq_target_io
*tio
= rq
->special
;
1226 blk_complete_request(rq
);
1230 * Complete the not-mapped clone and the original request with the error status
1231 * through softirq context.
1232 * Target's rq_end_io() function isn't called.
1233 * This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
1235 static void dm_kill_unmapped_request(struct request
*rq
, int error
)
1237 rq
->cmd_flags
|= REQ_FAILED
;
1238 dm_complete_request(rq
, error
);
1242 * Called with the clone's queue lock held
1244 static void end_clone_request(struct request
*clone
, int error
)
1246 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1248 if (!clone
->q
->mq_ops
) {
1250 * For just cleaning up the information of the queue in which
1251 * the clone was dispatched.
1252 * The clone is *NOT* freed actually here because it is alloced
1253 * from dm own mempool (REQ_ALLOCED isn't set).
1255 __blk_put_request(clone
->q
, clone
);
1259 * Actual request completion is done in a softirq context which doesn't
1260 * hold the clone's queue lock. Otherwise, deadlock could occur because:
1261 * - another request may be submitted by the upper level driver
1262 * of the stacking during the completion
1263 * - the submission which requires queue lock may be done
1264 * against this clone's queue
1266 dm_complete_request(tio
->orig
, error
);
1270 * Return maximum size of I/O possible at the supplied sector up to the current
1273 static sector_t
max_io_len_target_boundary(sector_t sector
, struct dm_target
*ti
)
1275 sector_t target_offset
= dm_target_offset(ti
, sector
);
1277 return ti
->len
- target_offset
;
1280 static sector_t
max_io_len(sector_t sector
, struct dm_target
*ti
)
1282 sector_t len
= max_io_len_target_boundary(sector
, ti
);
1283 sector_t offset
, max_len
;
1286 * Does the target need to split even further?
1288 if (ti
->max_io_len
) {
1289 offset
= dm_target_offset(ti
, sector
);
1290 if (unlikely(ti
->max_io_len
& (ti
->max_io_len
- 1)))
1291 max_len
= sector_div(offset
, ti
->max_io_len
);
1293 max_len
= offset
& (ti
->max_io_len
- 1);
1294 max_len
= ti
->max_io_len
- max_len
;
1303 int dm_set_target_max_io_len(struct dm_target
*ti
, sector_t len
)
1305 if (len
> UINT_MAX
) {
1306 DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
1307 (unsigned long long)len
, UINT_MAX
);
1308 ti
->error
= "Maximum size of target IO is too large";
1312 ti
->max_io_len
= (uint32_t) len
;
1316 EXPORT_SYMBOL_GPL(dm_set_target_max_io_len
);
1319 * A target may call dm_accept_partial_bio only from the map routine. It is
1320 * allowed for all bio types except REQ_FLUSH.
1322 * dm_accept_partial_bio informs the dm that the target only wants to process
1323 * additional n_sectors sectors of the bio and the rest of the data should be
1324 * sent in a next bio.
1326 * A diagram that explains the arithmetics:
1327 * +--------------------+---------------+-------+
1329 * +--------------------+---------------+-------+
1331 * <-------------- *tio->len_ptr --------------->
1332 * <------- bi_size ------->
1335 * Region 1 was already iterated over with bio_advance or similar function.
1336 * (it may be empty if the target doesn't use bio_advance)
1337 * Region 2 is the remaining bio size that the target wants to process.
1338 * (it may be empty if region 1 is non-empty, although there is no reason
1340 * The target requires that region 3 is to be sent in the next bio.
1342 * If the target wants to receive multiple copies of the bio (via num_*bios, etc),
1343 * the partially processed part (the sum of regions 1+2) must be the same for all
1344 * copies of the bio.
1346 void dm_accept_partial_bio(struct bio
*bio
, unsigned n_sectors
)
1348 struct dm_target_io
*tio
= container_of(bio
, struct dm_target_io
, clone
);
1349 unsigned bi_size
= bio
->bi_iter
.bi_size
>> SECTOR_SHIFT
;
1350 BUG_ON(bio
->bi_rw
& REQ_FLUSH
);
1351 BUG_ON(bi_size
> *tio
->len_ptr
);
1352 BUG_ON(n_sectors
> bi_size
);
1353 *tio
->len_ptr
-= bi_size
- n_sectors
;
1354 bio
->bi_iter
.bi_size
= n_sectors
<< SECTOR_SHIFT
;
1356 EXPORT_SYMBOL_GPL(dm_accept_partial_bio
);
1358 static void __map_bio(struct dm_target_io
*tio
)
1362 struct mapped_device
*md
;
1363 struct bio
*clone
= &tio
->clone
;
1364 struct dm_target
*ti
= tio
->ti
;
1366 clone
->bi_end_io
= clone_endio
;
1369 * Map the clone. If r == 0 we don't need to do
1370 * anything, the target has assumed ownership of
1373 atomic_inc(&tio
->io
->io_count
);
1374 sector
= clone
->bi_iter
.bi_sector
;
1375 r
= ti
->type
->map(ti
, clone
);
1376 if (r
== DM_MAPIO_REMAPPED
) {
1377 /* the bio has been remapped so dispatch it */
1379 trace_block_bio_remap(bdev_get_queue(clone
->bi_bdev
), clone
,
1380 tio
->io
->bio
->bi_bdev
->bd_dev
, sector
);
1382 generic_make_request(clone
);
1383 } else if (r
< 0 || r
== DM_MAPIO_REQUEUE
) {
1384 /* error the io and bail out, or requeue it if needed */
1386 dec_pending(tio
->io
, r
);
1389 DMWARN("unimplemented target map return value: %d", r
);
1395 struct mapped_device
*md
;
1396 struct dm_table
*map
;
1400 unsigned sector_count
;
1403 static void bio_setup_sector(struct bio
*bio
, sector_t sector
, unsigned len
)
1405 bio
->bi_iter
.bi_sector
= sector
;
1406 bio
->bi_iter
.bi_size
= to_bytes(len
);
1410 * Creates a bio that consists of range of complete bvecs.
1412 static void clone_bio(struct dm_target_io
*tio
, struct bio
*bio
,
1413 sector_t sector
, unsigned len
)
1415 struct bio
*clone
= &tio
->clone
;
1417 __bio_clone_fast(clone
, bio
);
1419 if (bio_integrity(bio
))
1420 bio_integrity_clone(clone
, bio
, GFP_NOIO
);
1422 bio_advance(clone
, to_bytes(sector
- clone
->bi_iter
.bi_sector
));
1423 clone
->bi_iter
.bi_size
= to_bytes(len
);
1425 if (bio_integrity(bio
))
1426 bio_integrity_trim(clone
, 0, len
);
1429 static struct dm_target_io
*alloc_tio(struct clone_info
*ci
,
1430 struct dm_target
*ti
,
1431 unsigned target_bio_nr
)
1433 struct dm_target_io
*tio
;
1436 clone
= bio_alloc_bioset(GFP_NOIO
, 0, ci
->md
->bs
);
1437 tio
= container_of(clone
, struct dm_target_io
, clone
);
1441 tio
->target_bio_nr
= target_bio_nr
;
1446 static void __clone_and_map_simple_bio(struct clone_info
*ci
,
1447 struct dm_target
*ti
,
1448 unsigned target_bio_nr
, unsigned *len
)
1450 struct dm_target_io
*tio
= alloc_tio(ci
, ti
, target_bio_nr
);
1451 struct bio
*clone
= &tio
->clone
;
1455 __bio_clone_fast(clone
, ci
->bio
);
1457 bio_setup_sector(clone
, ci
->sector
, *len
);
1462 static void __send_duplicate_bios(struct clone_info
*ci
, struct dm_target
*ti
,
1463 unsigned num_bios
, unsigned *len
)
1465 unsigned target_bio_nr
;
1467 for (target_bio_nr
= 0; target_bio_nr
< num_bios
; target_bio_nr
++)
1468 __clone_and_map_simple_bio(ci
, ti
, target_bio_nr
, len
);
1471 static int __send_empty_flush(struct clone_info
*ci
)
1473 unsigned target_nr
= 0;
1474 struct dm_target
*ti
;
1476 BUG_ON(bio_has_data(ci
->bio
));
1477 while ((ti
= dm_table_get_target(ci
->map
, target_nr
++)))
1478 __send_duplicate_bios(ci
, ti
, ti
->num_flush_bios
, NULL
);
1483 static void __clone_and_map_data_bio(struct clone_info
*ci
, struct dm_target
*ti
,
1484 sector_t sector
, unsigned *len
)
1486 struct bio
*bio
= ci
->bio
;
1487 struct dm_target_io
*tio
;
1488 unsigned target_bio_nr
;
1489 unsigned num_target_bios
= 1;
1492 * Does the target want to receive duplicate copies of the bio?
1494 if (bio_data_dir(bio
) == WRITE
&& ti
->num_write_bios
)
1495 num_target_bios
= ti
->num_write_bios(ti
, bio
);
1497 for (target_bio_nr
= 0; target_bio_nr
< num_target_bios
; target_bio_nr
++) {
1498 tio
= alloc_tio(ci
, ti
, target_bio_nr
);
1500 clone_bio(tio
, bio
, sector
, *len
);
1505 typedef unsigned (*get_num_bios_fn
)(struct dm_target
*ti
);
1507 static unsigned get_num_discard_bios(struct dm_target
*ti
)
1509 return ti
->num_discard_bios
;
1512 static unsigned get_num_write_same_bios(struct dm_target
*ti
)
1514 return ti
->num_write_same_bios
;
1517 typedef bool (*is_split_required_fn
)(struct dm_target
*ti
);
1519 static bool is_split_required_for_discard(struct dm_target
*ti
)
1521 return ti
->split_discard_bios
;
1524 static int __send_changing_extent_only(struct clone_info
*ci
,
1525 get_num_bios_fn get_num_bios
,
1526 is_split_required_fn is_split_required
)
1528 struct dm_target
*ti
;
1533 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1534 if (!dm_target_is_valid(ti
))
1538 * Even though the device advertised support for this type of
1539 * request, that does not mean every target supports it, and
1540 * reconfiguration might also have changed that since the
1541 * check was performed.
1543 num_bios
= get_num_bios
? get_num_bios(ti
) : 0;
1547 if (is_split_required
&& !is_split_required(ti
))
1548 len
= min((sector_t
)ci
->sector_count
, max_io_len_target_boundary(ci
->sector
, ti
));
1550 len
= min((sector_t
)ci
->sector_count
, max_io_len(ci
->sector
, ti
));
1552 __send_duplicate_bios(ci
, ti
, num_bios
, &len
);
1555 } while (ci
->sector_count
-= len
);
1560 static int __send_discard(struct clone_info
*ci
)
1562 return __send_changing_extent_only(ci
, get_num_discard_bios
,
1563 is_split_required_for_discard
);
1566 static int __send_write_same(struct clone_info
*ci
)
1568 return __send_changing_extent_only(ci
, get_num_write_same_bios
, NULL
);
1572 * Select the correct strategy for processing a non-flush bio.
1574 static int __split_and_process_non_flush(struct clone_info
*ci
)
1576 struct bio
*bio
= ci
->bio
;
1577 struct dm_target
*ti
;
1580 if (unlikely(bio
->bi_rw
& REQ_DISCARD
))
1581 return __send_discard(ci
);
1582 else if (unlikely(bio
->bi_rw
& REQ_WRITE_SAME
))
1583 return __send_write_same(ci
);
1585 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1586 if (!dm_target_is_valid(ti
))
1589 len
= min_t(sector_t
, max_io_len(ci
->sector
, ti
), ci
->sector_count
);
1591 __clone_and_map_data_bio(ci
, ti
, ci
->sector
, &len
);
1594 ci
->sector_count
-= len
;
1600 * Entry point to split a bio into clones and submit them to the targets.
1602 static void __split_and_process_bio(struct mapped_device
*md
,
1603 struct dm_table
*map
, struct bio
*bio
)
1605 struct clone_info ci
;
1608 if (unlikely(!map
)) {
1615 ci
.io
= alloc_io(md
);
1617 atomic_set(&ci
.io
->io_count
, 1);
1620 spin_lock_init(&ci
.io
->endio_lock
);
1621 ci
.sector
= bio
->bi_iter
.bi_sector
;
1623 start_io_acct(ci
.io
);
1625 if (bio
->bi_rw
& REQ_FLUSH
) {
1626 ci
.bio
= &ci
.md
->flush_bio
;
1627 ci
.sector_count
= 0;
1628 error
= __send_empty_flush(&ci
);
1629 /* dec_pending submits any data associated with flush */
1632 ci
.sector_count
= bio_sectors(bio
);
1633 while (ci
.sector_count
&& !error
)
1634 error
= __split_and_process_non_flush(&ci
);
1637 /* drop the extra reference count */
1638 dec_pending(ci
.io
, error
);
1640 /*-----------------------------------------------------------------
1642 *---------------------------------------------------------------*/
1644 static int dm_merge_bvec(struct request_queue
*q
,
1645 struct bvec_merge_data
*bvm
,
1646 struct bio_vec
*biovec
)
1648 struct mapped_device
*md
= q
->queuedata
;
1649 struct dm_table
*map
= dm_get_live_table_fast(md
);
1650 struct dm_target
*ti
;
1651 sector_t max_sectors
;
1657 ti
= dm_table_find_target(map
, bvm
->bi_sector
);
1658 if (!dm_target_is_valid(ti
))
1662 * Find maximum amount of I/O that won't need splitting
1664 max_sectors
= min(max_io_len(bvm
->bi_sector
, ti
),
1665 (sector_t
) queue_max_sectors(q
));
1666 max_size
= (max_sectors
<< SECTOR_SHIFT
) - bvm
->bi_size
;
1667 if (unlikely(max_size
< 0)) /* this shouldn't _ever_ happen */
1671 * merge_bvec_fn() returns number of bytes
1672 * it can accept at this offset
1673 * max is precomputed maximal io size
1675 if (max_size
&& ti
->type
->merge
)
1676 max_size
= ti
->type
->merge(ti
, bvm
, biovec
, max_size
);
1678 * If the target doesn't support merge method and some of the devices
1679 * provided their merge_bvec method (we know this by looking for the
1680 * max_hw_sectors that dm_set_device_limits may set), then we can't
1681 * allow bios with multiple vector entries. So always set max_size
1682 * to 0, and the code below allows just one page.
1684 else if (queue_max_hw_sectors(q
) <= PAGE_SIZE
>> 9)
1688 dm_put_live_table_fast(md
);
1690 * Always allow an entire first page
1692 if (max_size
<= biovec
->bv_len
&& !(bvm
->bi_size
>> SECTOR_SHIFT
))
1693 max_size
= biovec
->bv_len
;
1699 * The request function that just remaps the bio built up by
1702 static void dm_make_request(struct request_queue
*q
, struct bio
*bio
)
1704 int rw
= bio_data_dir(bio
);
1705 struct mapped_device
*md
= q
->queuedata
;
1707 struct dm_table
*map
;
1709 map
= dm_get_live_table(md
, &srcu_idx
);
1711 generic_start_io_acct(rw
, bio_sectors(bio
), &dm_disk(md
)->part0
);
1713 /* if we're suspended, we have to queue this io for later */
1714 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
))) {
1715 dm_put_live_table(md
, srcu_idx
);
1717 if (bio_rw(bio
) != READA
)
1724 __split_and_process_bio(md
, map
, bio
);
1725 dm_put_live_table(md
, srcu_idx
);
1729 int dm_request_based(struct mapped_device
*md
)
1731 return blk_queue_stackable(md
->queue
);
1734 static void dm_dispatch_clone_request(struct request
*clone
, struct request
*rq
)
1738 if (blk_queue_io_stat(clone
->q
))
1739 clone
->cmd_flags
|= REQ_IO_STAT
;
1741 clone
->start_time
= jiffies
;
1742 r
= blk_insert_cloned_request(clone
->q
, clone
);
1744 /* must complete clone in terms of original request */
1745 dm_complete_request(rq
, r
);
1748 static int dm_rq_bio_constructor(struct bio
*bio
, struct bio
*bio_orig
,
1751 struct dm_rq_target_io
*tio
= data
;
1752 struct dm_rq_clone_bio_info
*info
=
1753 container_of(bio
, struct dm_rq_clone_bio_info
, clone
);
1755 info
->orig
= bio_orig
;
1757 bio
->bi_end_io
= end_clone_bio
;
1762 static int setup_clone(struct request
*clone
, struct request
*rq
,
1763 struct dm_rq_target_io
*tio
, gfp_t gfp_mask
)
1767 r
= blk_rq_prep_clone(clone
, rq
, tio
->md
->bs
, gfp_mask
,
1768 dm_rq_bio_constructor
, tio
);
1772 clone
->cmd
= rq
->cmd
;
1773 clone
->cmd_len
= rq
->cmd_len
;
1774 clone
->sense
= rq
->sense
;
1775 clone
->end_io
= end_clone_request
;
1776 clone
->end_io_data
= tio
;
1783 static struct request
*clone_rq(struct request
*rq
, struct mapped_device
*md
,
1784 struct dm_rq_target_io
*tio
, gfp_t gfp_mask
)
1786 struct request
*clone
= alloc_clone_request(md
, gfp_mask
);
1791 blk_rq_init(NULL
, clone
);
1792 if (setup_clone(clone
, rq
, tio
, gfp_mask
)) {
1794 free_clone_request(md
, clone
);
1801 static void map_tio_request(struct kthread_work
*work
);
1803 static struct dm_rq_target_io
*prep_tio(struct request
*rq
,
1804 struct mapped_device
*md
, gfp_t gfp_mask
)
1806 struct dm_rq_target_io
*tio
;
1808 struct dm_table
*table
;
1810 tio
= alloc_rq_tio(md
, gfp_mask
);
1819 memset(&tio
->info
, 0, sizeof(tio
->info
));
1820 init_kthread_work(&tio
->work
, map_tio_request
);
1822 table
= dm_get_live_table(md
, &srcu_idx
);
1823 if (!dm_table_mq_request_based(table
)) {
1824 if (!clone_rq(rq
, md
, tio
, gfp_mask
)) {
1825 dm_put_live_table(md
, srcu_idx
);
1830 dm_put_live_table(md
, srcu_idx
);
1836 * Called with the queue lock held.
1838 static int dm_prep_fn(struct request_queue
*q
, struct request
*rq
)
1840 struct mapped_device
*md
= q
->queuedata
;
1841 struct dm_rq_target_io
*tio
;
1843 if (unlikely(rq
->special
)) {
1844 DMWARN("Already has something in rq->special.");
1845 return BLKPREP_KILL
;
1848 tio
= prep_tio(rq
, md
, GFP_ATOMIC
);
1850 return BLKPREP_DEFER
;
1853 rq
->cmd_flags
|= REQ_DONTPREP
;
1860 * 0 : the request has been processed
1861 * DM_MAPIO_REQUEUE : the original request needs to be requeued
1862 * < 0 : the request was completed due to failure
1864 static int map_request(struct dm_target
*ti
, struct request
*rq
,
1865 struct mapped_device
*md
)
1868 struct dm_rq_target_io
*tio
= rq
->special
;
1869 struct request
*clone
= NULL
;
1873 r
= ti
->type
->map_rq(ti
, clone
, &tio
->info
);
1875 r
= ti
->type
->clone_and_map_rq(ti
, rq
, &tio
->info
, &clone
);
1877 /* The target wants to complete the I/O */
1878 dm_kill_unmapped_request(rq
, r
);
1882 return DM_MAPIO_REQUEUE
;
1883 if (setup_clone(clone
, rq
, tio
, GFP_KERNEL
)) {
1885 ti
->type
->release_clone_rq(clone
);
1886 return DM_MAPIO_REQUEUE
;
1891 case DM_MAPIO_SUBMITTED
:
1892 /* The target has taken the I/O to submit by itself later */
1894 case DM_MAPIO_REMAPPED
:
1895 /* The target has remapped the I/O so dispatch it */
1896 trace_block_rq_remap(clone
->q
, clone
, disk_devt(dm_disk(md
)),
1898 dm_dispatch_clone_request(clone
, rq
);
1900 case DM_MAPIO_REQUEUE
:
1901 /* The target wants to requeue the I/O */
1902 dm_requeue_unmapped_request(clone
);
1906 DMWARN("unimplemented target map return value: %d", r
);
1910 /* The target wants to complete the I/O */
1911 dm_kill_unmapped_request(rq
, r
);
1918 static void map_tio_request(struct kthread_work
*work
)
1920 struct dm_rq_target_io
*tio
= container_of(work
, struct dm_rq_target_io
, work
);
1921 struct request
*rq
= tio
->orig
;
1922 struct mapped_device
*md
= tio
->md
;
1924 if (map_request(tio
->ti
, rq
, md
) == DM_MAPIO_REQUEUE
)
1925 dm_requeue_unmapped_original_request(md
, rq
);
1928 static void dm_start_request(struct mapped_device
*md
, struct request
*orig
)
1930 blk_start_request(orig
);
1931 atomic_inc(&md
->pending
[rq_data_dir(orig
)]);
1934 * Hold the md reference here for the in-flight I/O.
1935 * We can't rely on the reference count by device opener,
1936 * because the device may be closed during the request completion
1937 * when all bios are completed.
1938 * See the comment in rq_completed() too.
1944 * q->request_fn for request-based dm.
1945 * Called with the queue lock held.
1947 static void dm_request_fn(struct request_queue
*q
)
1949 struct mapped_device
*md
= q
->queuedata
;
1951 struct dm_table
*map
= dm_get_live_table(md
, &srcu_idx
);
1952 struct dm_target
*ti
;
1954 struct dm_rq_target_io
*tio
;
1958 * For suspend, check blk_queue_stopped() and increment
1959 * ->pending within a single queue_lock not to increment the
1960 * number of in-flight I/Os after the queue is stopped in
1963 while (!blk_queue_stopped(q
)) {
1964 rq
= blk_peek_request(q
);
1968 /* always use block 0 to find the target for flushes for now */
1970 if (!(rq
->cmd_flags
& REQ_FLUSH
))
1971 pos
= blk_rq_pos(rq
);
1973 ti
= dm_table_find_target(map
, pos
);
1974 if (!dm_target_is_valid(ti
)) {
1976 * Must perform setup, that rq_completed() requires,
1977 * before calling dm_kill_unmapped_request
1979 DMERR_LIMIT("request attempted access beyond the end of device");
1980 dm_start_request(md
, rq
);
1981 dm_kill_unmapped_request(rq
, -EIO
);
1985 if (ti
->type
->busy
&& ti
->type
->busy(ti
))
1988 dm_start_request(md
, rq
);
1991 /* Establish tio->ti before queuing work (map_tio_request) */
1993 queue_kthread_work(&md
->kworker
, &tio
->work
);
1994 BUG_ON(!irqs_disabled());
2000 blk_delay_queue(q
, HZ
/ 10);
2002 dm_put_live_table(md
, srcu_idx
);
2005 static int dm_any_congested(void *congested_data
, int bdi_bits
)
2008 struct mapped_device
*md
= congested_data
;
2009 struct dm_table
*map
;
2011 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
2012 map
= dm_get_live_table_fast(md
);
2015 * Request-based dm cares about only own queue for
2016 * the query about congestion status of request_queue
2018 if (dm_request_based(md
))
2019 r
= md
->queue
->backing_dev_info
.state
&
2022 r
= dm_table_any_congested(map
, bdi_bits
);
2024 dm_put_live_table_fast(md
);
2030 /*-----------------------------------------------------------------
2031 * An IDR is used to keep track of allocated minor numbers.
2032 *---------------------------------------------------------------*/
2033 static void free_minor(int minor
)
2035 spin_lock(&_minor_lock
);
2036 idr_remove(&_minor_idr
, minor
);
2037 spin_unlock(&_minor_lock
);
2041 * See if the device with a specific minor # is free.
2043 static int specific_minor(int minor
)
2047 if (minor
>= (1 << MINORBITS
))
2050 idr_preload(GFP_KERNEL
);
2051 spin_lock(&_minor_lock
);
2053 r
= idr_alloc(&_minor_idr
, MINOR_ALLOCED
, minor
, minor
+ 1, GFP_NOWAIT
);
2055 spin_unlock(&_minor_lock
);
2058 return r
== -ENOSPC
? -EBUSY
: r
;
2062 static int next_free_minor(int *minor
)
2066 idr_preload(GFP_KERNEL
);
2067 spin_lock(&_minor_lock
);
2069 r
= idr_alloc(&_minor_idr
, MINOR_ALLOCED
, 0, 1 << MINORBITS
, GFP_NOWAIT
);
2071 spin_unlock(&_minor_lock
);
2079 static const struct block_device_operations dm_blk_dops
;
2081 static void dm_wq_work(struct work_struct
*work
);
2083 static void dm_init_md_queue(struct mapped_device
*md
)
2086 * Request-based dm devices cannot be stacked on top of bio-based dm
2087 * devices. The type of this dm device has not been decided yet.
2088 * The type is decided at the first table loading time.
2089 * To prevent problematic device stacking, clear the queue flag
2090 * for request stacking support until then.
2092 * This queue is new, so no concurrency on the queue_flags.
2094 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE
, md
->queue
);
2096 md
->queue
->queuedata
= md
;
2097 md
->queue
->backing_dev_info
.congested_fn
= dm_any_congested
;
2098 md
->queue
->backing_dev_info
.congested_data
= md
;
2100 blk_queue_bounce_limit(md
->queue
, BLK_BOUNCE_ANY
);
2104 * Allocate and initialise a blank device with a given minor.
2106 static struct mapped_device
*alloc_dev(int minor
)
2109 struct mapped_device
*md
= kzalloc(sizeof(*md
), GFP_KERNEL
);
2113 DMWARN("unable to allocate device, out of memory.");
2117 if (!try_module_get(THIS_MODULE
))
2118 goto bad_module_get
;
2120 /* get a minor number for the dev */
2121 if (minor
== DM_ANY_MINOR
)
2122 r
= next_free_minor(&minor
);
2124 r
= specific_minor(minor
);
2128 r
= init_srcu_struct(&md
->io_barrier
);
2130 goto bad_io_barrier
;
2132 md
->type
= DM_TYPE_NONE
;
2133 mutex_init(&md
->suspend_lock
);
2134 mutex_init(&md
->type_lock
);
2135 mutex_init(&md
->table_devices_lock
);
2136 spin_lock_init(&md
->deferred_lock
);
2137 atomic_set(&md
->holders
, 1);
2138 atomic_set(&md
->open_count
, 0);
2139 atomic_set(&md
->event_nr
, 0);
2140 atomic_set(&md
->uevent_seq
, 0);
2141 INIT_LIST_HEAD(&md
->uevent_list
);
2142 INIT_LIST_HEAD(&md
->table_devices
);
2143 spin_lock_init(&md
->uevent_lock
);
2145 md
->queue
= blk_alloc_queue(GFP_KERNEL
);
2149 dm_init_md_queue(md
);
2151 md
->disk
= alloc_disk(1);
2155 atomic_set(&md
->pending
[0], 0);
2156 atomic_set(&md
->pending
[1], 0);
2157 init_waitqueue_head(&md
->wait
);
2158 INIT_WORK(&md
->work
, dm_wq_work
);
2159 init_waitqueue_head(&md
->eventq
);
2160 init_completion(&md
->kobj_holder
.completion
);
2161 md
->kworker_task
= NULL
;
2163 md
->disk
->major
= _major
;
2164 md
->disk
->first_minor
= minor
;
2165 md
->disk
->fops
= &dm_blk_dops
;
2166 md
->disk
->queue
= md
->queue
;
2167 md
->disk
->private_data
= md
;
2168 sprintf(md
->disk
->disk_name
, "dm-%d", minor
);
2170 format_dev_t(md
->name
, MKDEV(_major
, minor
));
2172 md
->wq
= alloc_workqueue("kdmflush", WQ_MEM_RECLAIM
, 0);
2176 md
->bdev
= bdget_disk(md
->disk
, 0);
2180 bio_init(&md
->flush_bio
);
2181 md
->flush_bio
.bi_bdev
= md
->bdev
;
2182 md
->flush_bio
.bi_rw
= WRITE_FLUSH
;
2184 dm_stats_init(&md
->stats
);
2186 /* Populate the mapping, nobody knows we exist yet */
2187 spin_lock(&_minor_lock
);
2188 old_md
= idr_replace(&_minor_idr
, md
, minor
);
2189 spin_unlock(&_minor_lock
);
2191 BUG_ON(old_md
!= MINOR_ALLOCED
);
2196 destroy_workqueue(md
->wq
);
2198 del_gendisk(md
->disk
);
2201 blk_cleanup_queue(md
->queue
);
2203 cleanup_srcu_struct(&md
->io_barrier
);
2207 module_put(THIS_MODULE
);
2213 static void unlock_fs(struct mapped_device
*md
);
2215 static void free_dev(struct mapped_device
*md
)
2217 int minor
= MINOR(disk_devt(md
->disk
));
2220 destroy_workqueue(md
->wq
);
2222 if (md
->kworker_task
)
2223 kthread_stop(md
->kworker_task
);
2225 mempool_destroy(md
->io_pool
);
2227 mempool_destroy(md
->rq_pool
);
2229 bioset_free(md
->bs
);
2231 cleanup_srcu_struct(&md
->io_barrier
);
2232 free_table_devices(&md
->table_devices
);
2233 dm_stats_cleanup(&md
->stats
);
2235 spin_lock(&_minor_lock
);
2236 md
->disk
->private_data
= NULL
;
2237 spin_unlock(&_minor_lock
);
2238 if (blk_get_integrity(md
->disk
))
2239 blk_integrity_unregister(md
->disk
);
2240 del_gendisk(md
->disk
);
2242 blk_cleanup_queue(md
->queue
);
2246 module_put(THIS_MODULE
);
2250 static void __bind_mempools(struct mapped_device
*md
, struct dm_table
*t
)
2252 struct dm_md_mempools
*p
= dm_table_get_md_mempools(t
);
2254 if (md
->io_pool
&& md
->bs
) {
2255 /* The md already has necessary mempools. */
2256 if (dm_table_get_type(t
) == DM_TYPE_BIO_BASED
) {
2258 * Reload bioset because front_pad may have changed
2259 * because a different table was loaded.
2261 bioset_free(md
->bs
);
2266 * There's no need to reload with request-based dm
2267 * because the size of front_pad doesn't change.
2268 * Note for future: If you are to reload bioset,
2269 * prep-ed requests in the queue may refer
2270 * to bio from the old bioset, so you must walk
2271 * through the queue to unprep.
2276 BUG_ON(!p
|| md
->io_pool
|| md
->rq_pool
|| md
->bs
);
2278 md
->io_pool
= p
->io_pool
;
2280 md
->rq_pool
= p
->rq_pool
;
2286 /* mempool bind completed, now no need any mempools in the table */
2287 dm_table_free_md_mempools(t
);
2291 * Bind a table to the device.
2293 static void event_callback(void *context
)
2295 unsigned long flags
;
2297 struct mapped_device
*md
= (struct mapped_device
*) context
;
2299 spin_lock_irqsave(&md
->uevent_lock
, flags
);
2300 list_splice_init(&md
->uevent_list
, &uevents
);
2301 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
2303 dm_send_uevents(&uevents
, &disk_to_dev(md
->disk
)->kobj
);
2305 atomic_inc(&md
->event_nr
);
2306 wake_up(&md
->eventq
);
2310 * Protected by md->suspend_lock obtained by dm_swap_table().
2312 static void __set_size(struct mapped_device
*md
, sector_t size
)
2314 set_capacity(md
->disk
, size
);
2316 i_size_write(md
->bdev
->bd_inode
, (loff_t
)size
<< SECTOR_SHIFT
);
2320 * Return 1 if the queue has a compulsory merge_bvec_fn function.
2322 * If this function returns 0, then the device is either a non-dm
2323 * device without a merge_bvec_fn, or it is a dm device that is
2324 * able to split any bios it receives that are too big.
2326 int dm_queue_merge_is_compulsory(struct request_queue
*q
)
2328 struct mapped_device
*dev_md
;
2330 if (!q
->merge_bvec_fn
)
2333 if (q
->make_request_fn
== dm_make_request
) {
2334 dev_md
= q
->queuedata
;
2335 if (test_bit(DMF_MERGE_IS_OPTIONAL
, &dev_md
->flags
))
2342 static int dm_device_merge_is_compulsory(struct dm_target
*ti
,
2343 struct dm_dev
*dev
, sector_t start
,
2344 sector_t len
, void *data
)
2346 struct block_device
*bdev
= dev
->bdev
;
2347 struct request_queue
*q
= bdev_get_queue(bdev
);
2349 return dm_queue_merge_is_compulsory(q
);
2353 * Return 1 if it is acceptable to ignore merge_bvec_fn based
2354 * on the properties of the underlying devices.
2356 static int dm_table_merge_is_optional(struct dm_table
*table
)
2359 struct dm_target
*ti
;
2361 while (i
< dm_table_get_num_targets(table
)) {
2362 ti
= dm_table_get_target(table
, i
++);
2364 if (ti
->type
->iterate_devices
&&
2365 ti
->type
->iterate_devices(ti
, dm_device_merge_is_compulsory
, NULL
))
2373 * Returns old map, which caller must destroy.
2375 static struct dm_table
*__bind(struct mapped_device
*md
, struct dm_table
*t
,
2376 struct queue_limits
*limits
)
2378 struct dm_table
*old_map
;
2379 struct request_queue
*q
= md
->queue
;
2381 int merge_is_optional
;
2383 size
= dm_table_get_size(t
);
2386 * Wipe any geometry if the size of the table changed.
2388 if (size
!= dm_get_size(md
))
2389 memset(&md
->geometry
, 0, sizeof(md
->geometry
));
2391 __set_size(md
, size
);
2393 dm_table_event_callback(t
, event_callback
, md
);
2396 * The queue hasn't been stopped yet, if the old table type wasn't
2397 * for request-based during suspension. So stop it to prevent
2398 * I/O mapping before resume.
2399 * This must be done before setting the queue restrictions,
2400 * because request-based dm may be run just after the setting.
2402 if (dm_table_request_based(t
) && !blk_queue_stopped(q
))
2405 __bind_mempools(md
, t
);
2407 merge_is_optional
= dm_table_merge_is_optional(t
);
2409 old_map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
2410 rcu_assign_pointer(md
->map
, t
);
2411 md
->immutable_target_type
= dm_table_get_immutable_target_type(t
);
2413 dm_table_set_restrictions(t
, q
, limits
);
2414 if (merge_is_optional
)
2415 set_bit(DMF_MERGE_IS_OPTIONAL
, &md
->flags
);
2417 clear_bit(DMF_MERGE_IS_OPTIONAL
, &md
->flags
);
2425 * Returns unbound table for the caller to free.
2427 static struct dm_table
*__unbind(struct mapped_device
*md
)
2429 struct dm_table
*map
= rcu_dereference_protected(md
->map
, 1);
2434 dm_table_event_callback(map
, NULL
, NULL
);
2435 RCU_INIT_POINTER(md
->map
, NULL
);
2442 * Constructor for a new device.
2444 int dm_create(int minor
, struct mapped_device
**result
)
2446 struct mapped_device
*md
;
2448 md
= alloc_dev(minor
);
2459 * Functions to manage md->type.
2460 * All are required to hold md->type_lock.
2462 void dm_lock_md_type(struct mapped_device
*md
)
2464 mutex_lock(&md
->type_lock
);
2467 void dm_unlock_md_type(struct mapped_device
*md
)
2469 mutex_unlock(&md
->type_lock
);
2472 void dm_set_md_type(struct mapped_device
*md
, unsigned type
)
2474 BUG_ON(!mutex_is_locked(&md
->type_lock
));
2478 unsigned dm_get_md_type(struct mapped_device
*md
)
2480 BUG_ON(!mutex_is_locked(&md
->type_lock
));
2484 static bool dm_md_type_request_based(struct mapped_device
*md
)
2486 unsigned table_type
= dm_get_md_type(md
);
2488 return (table_type
== DM_TYPE_REQUEST_BASED
||
2489 table_type
== DM_TYPE_MQ_REQUEST_BASED
);
2492 struct target_type
*dm_get_immutable_target_type(struct mapped_device
*md
)
2494 return md
->immutable_target_type
;
2498 * The queue_limits are only valid as long as you have a reference
2501 struct queue_limits
*dm_get_queue_limits(struct mapped_device
*md
)
2503 BUG_ON(!atomic_read(&md
->holders
));
2504 return &md
->queue
->limits
;
2506 EXPORT_SYMBOL_GPL(dm_get_queue_limits
);
2509 * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
2511 static int dm_init_request_based_queue(struct mapped_device
*md
)
2513 struct request_queue
*q
= NULL
;
2515 if (md
->queue
->elevator
)
2518 /* Fully initialize the queue */
2519 q
= blk_init_allocated_queue(md
->queue
, dm_request_fn
, NULL
);
2524 dm_init_md_queue(md
);
2525 blk_queue_softirq_done(md
->queue
, dm_softirq_done
);
2526 blk_queue_prep_rq(md
->queue
, dm_prep_fn
);
2528 /* Also initialize the request-based DM worker thread */
2529 init_kthread_worker(&md
->kworker
);
2530 md
->kworker_task
= kthread_run(kthread_worker_fn
, &md
->kworker
,
2531 "kdmwork-%s", dm_device_name(md
));
2533 elv_register_queue(md
->queue
);
2539 * Setup the DM device's queue based on md's type
2541 int dm_setup_md_queue(struct mapped_device
*md
)
2543 if (dm_md_type_request_based(md
)) {
2544 if (!dm_init_request_based_queue(md
)) {
2545 DMWARN("Cannot initialize queue for request-based mapped device");
2549 /* bio-based specific initialization */
2550 blk_queue_make_request(md
->queue
, dm_make_request
);
2551 blk_queue_merge_bvec(md
->queue
, dm_merge_bvec
);
2557 struct mapped_device
*dm_get_md(dev_t dev
)
2559 struct mapped_device
*md
;
2560 unsigned minor
= MINOR(dev
);
2562 if (MAJOR(dev
) != _major
|| minor
>= (1 << MINORBITS
))
2565 spin_lock(&_minor_lock
);
2567 md
= idr_find(&_minor_idr
, minor
);
2569 if ((md
== MINOR_ALLOCED
||
2570 (MINOR(disk_devt(dm_disk(md
))) != minor
) ||
2571 dm_deleting_md(md
) ||
2572 test_bit(DMF_FREEING
, &md
->flags
))) {
2580 spin_unlock(&_minor_lock
);
2584 EXPORT_SYMBOL_GPL(dm_get_md
);
2586 void *dm_get_mdptr(struct mapped_device
*md
)
2588 return md
->interface_ptr
;
2591 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
)
2593 md
->interface_ptr
= ptr
;
2596 void dm_get(struct mapped_device
*md
)
2598 atomic_inc(&md
->holders
);
2599 BUG_ON(test_bit(DMF_FREEING
, &md
->flags
));
2602 int dm_hold(struct mapped_device
*md
)
2604 spin_lock(&_minor_lock
);
2605 if (test_bit(DMF_FREEING
, &md
->flags
)) {
2606 spin_unlock(&_minor_lock
);
2610 spin_unlock(&_minor_lock
);
2613 EXPORT_SYMBOL_GPL(dm_hold
);
2615 const char *dm_device_name(struct mapped_device
*md
)
2619 EXPORT_SYMBOL_GPL(dm_device_name
);
2621 static void __dm_destroy(struct mapped_device
*md
, bool wait
)
2623 struct dm_table
*map
;
2628 map
= dm_get_live_table(md
, &srcu_idx
);
2630 spin_lock(&_minor_lock
);
2631 idr_replace(&_minor_idr
, MINOR_ALLOCED
, MINOR(disk_devt(dm_disk(md
))));
2632 set_bit(DMF_FREEING
, &md
->flags
);
2633 spin_unlock(&_minor_lock
);
2635 if (dm_request_based(md
))
2636 flush_kthread_worker(&md
->kworker
);
2639 * Take suspend_lock so that presuspend and postsuspend methods
2640 * do not race with internal suspend.
2642 mutex_lock(&md
->suspend_lock
);
2643 if (!dm_suspended_md(md
)) {
2644 dm_table_presuspend_targets(map
);
2645 dm_table_postsuspend_targets(map
);
2647 mutex_unlock(&md
->suspend_lock
);
2649 /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
2650 dm_put_live_table(md
, srcu_idx
);
2653 * Rare, but there may be I/O requests still going to complete,
2654 * for example. Wait for all references to disappear.
2655 * No one should increment the reference count of the mapped_device,
2656 * after the mapped_device state becomes DMF_FREEING.
2659 while (atomic_read(&md
->holders
))
2661 else if (atomic_read(&md
->holders
))
2662 DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
2663 dm_device_name(md
), atomic_read(&md
->holders
));
2666 dm_table_destroy(__unbind(md
));
2670 void dm_destroy(struct mapped_device
*md
)
2672 __dm_destroy(md
, true);
2675 void dm_destroy_immediate(struct mapped_device
*md
)
2677 __dm_destroy(md
, false);
2680 void dm_put(struct mapped_device
*md
)
2682 atomic_dec(&md
->holders
);
2684 EXPORT_SYMBOL_GPL(dm_put
);
2686 static int dm_wait_for_completion(struct mapped_device
*md
, int interruptible
)
2689 DECLARE_WAITQUEUE(wait
, current
);
2691 add_wait_queue(&md
->wait
, &wait
);
2694 set_current_state(interruptible
);
2696 if (!md_in_flight(md
))
2699 if (interruptible
== TASK_INTERRUPTIBLE
&&
2700 signal_pending(current
)) {
2707 set_current_state(TASK_RUNNING
);
2709 remove_wait_queue(&md
->wait
, &wait
);
2715 * Process the deferred bios
2717 static void dm_wq_work(struct work_struct
*work
)
2719 struct mapped_device
*md
= container_of(work
, struct mapped_device
,
2723 struct dm_table
*map
;
2725 map
= dm_get_live_table(md
, &srcu_idx
);
2727 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
2728 spin_lock_irq(&md
->deferred_lock
);
2729 c
= bio_list_pop(&md
->deferred
);
2730 spin_unlock_irq(&md
->deferred_lock
);
2735 if (dm_request_based(md
))
2736 generic_make_request(c
);
2738 __split_and_process_bio(md
, map
, c
);
2741 dm_put_live_table(md
, srcu_idx
);
2744 static void dm_queue_flush(struct mapped_device
*md
)
2746 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
2747 smp_mb__after_atomic();
2748 queue_work(md
->wq
, &md
->work
);
2752 * Swap in a new table, returning the old one for the caller to destroy.
2754 struct dm_table
*dm_swap_table(struct mapped_device
*md
, struct dm_table
*table
)
2756 struct dm_table
*live_map
= NULL
, *map
= ERR_PTR(-EINVAL
);
2757 struct queue_limits limits
;
2760 mutex_lock(&md
->suspend_lock
);
2762 /* device must be suspended */
2763 if (!dm_suspended_md(md
))
2767 * If the new table has no data devices, retain the existing limits.
2768 * This helps multipath with queue_if_no_path if all paths disappear,
2769 * then new I/O is queued based on these limits, and then some paths
2772 if (dm_table_has_no_data_devices(table
)) {
2773 live_map
= dm_get_live_table_fast(md
);
2775 limits
= md
->queue
->limits
;
2776 dm_put_live_table_fast(md
);
2780 r
= dm_calculate_queue_limits(table
, &limits
);
2787 map
= __bind(md
, table
, &limits
);
2790 mutex_unlock(&md
->suspend_lock
);
2795 * Functions to lock and unlock any filesystem running on the
2798 static int lock_fs(struct mapped_device
*md
)
2802 WARN_ON(md
->frozen_sb
);
2804 md
->frozen_sb
= freeze_bdev(md
->bdev
);
2805 if (IS_ERR(md
->frozen_sb
)) {
2806 r
= PTR_ERR(md
->frozen_sb
);
2807 md
->frozen_sb
= NULL
;
2811 set_bit(DMF_FROZEN
, &md
->flags
);
2816 static void unlock_fs(struct mapped_device
*md
)
2818 if (!test_bit(DMF_FROZEN
, &md
->flags
))
2821 thaw_bdev(md
->bdev
, md
->frozen_sb
);
2822 md
->frozen_sb
= NULL
;
2823 clear_bit(DMF_FROZEN
, &md
->flags
);
2827 * If __dm_suspend returns 0, the device is completely quiescent
2828 * now. There is no request-processing activity. All new requests
2829 * are being added to md->deferred list.
2831 * Caller must hold md->suspend_lock
2833 static int __dm_suspend(struct mapped_device
*md
, struct dm_table
*map
,
2834 unsigned suspend_flags
, int interruptible
)
2836 bool do_lockfs
= suspend_flags
& DM_SUSPEND_LOCKFS_FLAG
;
2837 bool noflush
= suspend_flags
& DM_SUSPEND_NOFLUSH_FLAG
;
2841 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2842 * This flag is cleared before dm_suspend returns.
2845 set_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
2848 * This gets reverted if there's an error later and the targets
2849 * provide the .presuspend_undo hook.
2851 dm_table_presuspend_targets(map
);
2854 * Flush I/O to the device.
2855 * Any I/O submitted after lock_fs() may not be flushed.
2856 * noflush takes precedence over do_lockfs.
2857 * (lock_fs() flushes I/Os and waits for them to complete.)
2859 if (!noflush
&& do_lockfs
) {
2862 dm_table_presuspend_undo_targets(map
);
2868 * Here we must make sure that no processes are submitting requests
2869 * to target drivers i.e. no one may be executing
2870 * __split_and_process_bio. This is called from dm_request and
2873 * To get all processes out of __split_and_process_bio in dm_request,
2874 * we take the write lock. To prevent any process from reentering
2875 * __split_and_process_bio from dm_request and quiesce the thread
2876 * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
2877 * flush_workqueue(md->wq).
2879 set_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
2881 synchronize_srcu(&md
->io_barrier
);
2884 * Stop md->queue before flushing md->wq in case request-based
2885 * dm defers requests to md->wq from md->queue.
2887 if (dm_request_based(md
)) {
2888 stop_queue(md
->queue
);
2889 flush_kthread_worker(&md
->kworker
);
2892 flush_workqueue(md
->wq
);
2895 * At this point no more requests are entering target request routines.
2896 * We call dm_wait_for_completion to wait for all existing requests
2899 r
= dm_wait_for_completion(md
, interruptible
);
2902 clear_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
2904 synchronize_srcu(&md
->io_barrier
);
2906 /* were we interrupted ? */
2910 if (dm_request_based(md
))
2911 start_queue(md
->queue
);
2914 dm_table_presuspend_undo_targets(map
);
2915 /* pushback list is already flushed, so skip flush */
2922 * We need to be able to change a mapping table under a mounted
2923 * filesystem. For example we might want to move some data in
2924 * the background. Before the table can be swapped with
2925 * dm_bind_table, dm_suspend must be called to flush any in
2926 * flight bios and ensure that any further io gets deferred.
2929 * Suspend mechanism in request-based dm.
2931 * 1. Flush all I/Os by lock_fs() if needed.
2932 * 2. Stop dispatching any I/O by stopping the request_queue.
2933 * 3. Wait for all in-flight I/Os to be completed or requeued.
2935 * To abort suspend, start the request_queue.
2937 int dm_suspend(struct mapped_device
*md
, unsigned suspend_flags
)
2939 struct dm_table
*map
= NULL
;
2943 mutex_lock_nested(&md
->suspend_lock
, SINGLE_DEPTH_NESTING
);
2945 if (dm_suspended_md(md
)) {
2950 if (dm_suspended_internally_md(md
)) {
2951 /* already internally suspended, wait for internal resume */
2952 mutex_unlock(&md
->suspend_lock
);
2953 r
= wait_on_bit(&md
->flags
, DMF_SUSPENDED_INTERNALLY
, TASK_INTERRUPTIBLE
);
2959 map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
2961 r
= __dm_suspend(md
, map
, suspend_flags
, TASK_INTERRUPTIBLE
);
2965 set_bit(DMF_SUSPENDED
, &md
->flags
);
2967 dm_table_postsuspend_targets(map
);
2970 mutex_unlock(&md
->suspend_lock
);
2974 static int __dm_resume(struct mapped_device
*md
, struct dm_table
*map
)
2977 int r
= dm_table_resume_targets(map
);
2985 * Flushing deferred I/Os must be done after targets are resumed
2986 * so that mapping of targets can work correctly.
2987 * Request-based dm is queueing the deferred I/Os in its request_queue.
2989 if (dm_request_based(md
))
2990 start_queue(md
->queue
);
2997 int dm_resume(struct mapped_device
*md
)
3000 struct dm_table
*map
= NULL
;
3003 mutex_lock_nested(&md
->suspend_lock
, SINGLE_DEPTH_NESTING
);
3005 if (!dm_suspended_md(md
))
3008 if (dm_suspended_internally_md(md
)) {
3009 /* already internally suspended, wait for internal resume */
3010 mutex_unlock(&md
->suspend_lock
);
3011 r
= wait_on_bit(&md
->flags
, DMF_SUSPENDED_INTERNALLY
, TASK_INTERRUPTIBLE
);
3017 map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
3018 if (!map
|| !dm_table_get_size(map
))
3021 r
= __dm_resume(md
, map
);
3025 clear_bit(DMF_SUSPENDED
, &md
->flags
);
3029 mutex_unlock(&md
->suspend_lock
);
3035 * Internal suspend/resume works like userspace-driven suspend. It waits
3036 * until all bios finish and prevents issuing new bios to the target drivers.
3037 * It may be used only from the kernel.
3040 static void __dm_internal_suspend(struct mapped_device
*md
, unsigned suspend_flags
)
3042 struct dm_table
*map
= NULL
;
3044 if (md
->internal_suspend_count
++)
3045 return; /* nested internal suspend */
3047 if (dm_suspended_md(md
)) {
3048 set_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3049 return; /* nest suspend */
3052 map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
3055 * Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
3056 * supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend
3057 * would require changing .presuspend to return an error -- avoid this
3058 * until there is a need for more elaborate variants of internal suspend.
3060 (void) __dm_suspend(md
, map
, suspend_flags
, TASK_UNINTERRUPTIBLE
);
3062 set_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3064 dm_table_postsuspend_targets(map
);
3067 static void __dm_internal_resume(struct mapped_device
*md
)
3069 BUG_ON(!md
->internal_suspend_count
);
3071 if (--md
->internal_suspend_count
)
3072 return; /* resume from nested internal suspend */
3074 if (dm_suspended_md(md
))
3075 goto done
; /* resume from nested suspend */
3078 * NOTE: existing callers don't need to call dm_table_resume_targets
3079 * (which may fail -- so best to avoid it for now by passing NULL map)
3081 (void) __dm_resume(md
, NULL
);
3084 clear_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3085 smp_mb__after_atomic();
3086 wake_up_bit(&md
->flags
, DMF_SUSPENDED_INTERNALLY
);
3089 void dm_internal_suspend_noflush(struct mapped_device
*md
)
3091 mutex_lock(&md
->suspend_lock
);
3092 __dm_internal_suspend(md
, DM_SUSPEND_NOFLUSH_FLAG
);
3093 mutex_unlock(&md
->suspend_lock
);
3095 EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush
);
3097 void dm_internal_resume(struct mapped_device
*md
)
3099 mutex_lock(&md
->suspend_lock
);
3100 __dm_internal_resume(md
);
3101 mutex_unlock(&md
->suspend_lock
);
3103 EXPORT_SYMBOL_GPL(dm_internal_resume
);
3106 * Fast variants of internal suspend/resume hold md->suspend_lock,
3107 * which prevents interaction with userspace-driven suspend.
3110 void dm_internal_suspend_fast(struct mapped_device
*md
)
3112 mutex_lock(&md
->suspend_lock
);
3113 if (dm_suspended_md(md
) || dm_suspended_internally_md(md
))
3116 set_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
3117 synchronize_srcu(&md
->io_barrier
);
3118 flush_workqueue(md
->wq
);
3119 dm_wait_for_completion(md
, TASK_UNINTERRUPTIBLE
);
3121 EXPORT_SYMBOL_GPL(dm_internal_suspend_fast
);
3123 void dm_internal_resume_fast(struct mapped_device
*md
)
3125 if (dm_suspended_md(md
) || dm_suspended_internally_md(md
))
3131 mutex_unlock(&md
->suspend_lock
);
3133 EXPORT_SYMBOL_GPL(dm_internal_resume_fast
);
3135 /*-----------------------------------------------------------------
3136 * Event notification.
3137 *---------------------------------------------------------------*/
3138 int dm_kobject_uevent(struct mapped_device
*md
, enum kobject_action action
,
3141 char udev_cookie
[DM_COOKIE_LENGTH
];
3142 char *envp
[] = { udev_cookie
, NULL
};
3145 return kobject_uevent(&disk_to_dev(md
->disk
)->kobj
, action
);
3147 snprintf(udev_cookie
, DM_COOKIE_LENGTH
, "%s=%u",
3148 DM_COOKIE_ENV_VAR_NAME
, cookie
);
3149 return kobject_uevent_env(&disk_to_dev(md
->disk
)->kobj
,
3154 uint32_t dm_next_uevent_seq(struct mapped_device
*md
)
3156 return atomic_add_return(1, &md
->uevent_seq
);
3159 uint32_t dm_get_event_nr(struct mapped_device
*md
)
3161 return atomic_read(&md
->event_nr
);
3164 int dm_wait_event(struct mapped_device
*md
, int event_nr
)
3166 return wait_event_interruptible(md
->eventq
,
3167 (event_nr
!= atomic_read(&md
->event_nr
)));
3170 void dm_uevent_add(struct mapped_device
*md
, struct list_head
*elist
)
3172 unsigned long flags
;
3174 spin_lock_irqsave(&md
->uevent_lock
, flags
);
3175 list_add(elist
, &md
->uevent_list
);
3176 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
3180 * The gendisk is only valid as long as you have a reference
3183 struct gendisk
*dm_disk(struct mapped_device
*md
)
3188 struct kobject
*dm_kobject(struct mapped_device
*md
)
3190 return &md
->kobj_holder
.kobj
;
3193 struct mapped_device
*dm_get_from_kobject(struct kobject
*kobj
)
3195 struct mapped_device
*md
;
3197 md
= container_of(kobj
, struct mapped_device
, kobj_holder
.kobj
);
3199 if (test_bit(DMF_FREEING
, &md
->flags
) ||
3207 int dm_suspended_md(struct mapped_device
*md
)
3209 return test_bit(DMF_SUSPENDED
, &md
->flags
);
3212 int dm_suspended_internally_md(struct mapped_device
*md
)
3214 return test_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3217 int dm_test_deferred_remove_flag(struct mapped_device
*md
)
3219 return test_bit(DMF_DEFERRED_REMOVE
, &md
->flags
);
3222 int dm_suspended(struct dm_target
*ti
)
3224 return dm_suspended_md(dm_table_get_md(ti
->table
));
3226 EXPORT_SYMBOL_GPL(dm_suspended
);
3228 int dm_noflush_suspending(struct dm_target
*ti
)
3230 return __noflush_suspending(dm_table_get_md(ti
->table
));
3232 EXPORT_SYMBOL_GPL(dm_noflush_suspending
);
3234 struct dm_md_mempools
*dm_alloc_md_mempools(unsigned type
, unsigned integrity
, unsigned per_bio_data_size
)
3236 struct dm_md_mempools
*pools
= kzalloc(sizeof(*pools
), GFP_KERNEL
);
3237 struct kmem_cache
*cachep
;
3238 unsigned int pool_size
= 0;
3239 unsigned int front_pad
;
3245 case DM_TYPE_BIO_BASED
:
3247 pool_size
= dm_get_reserved_bio_based_ios();
3248 front_pad
= roundup(per_bio_data_size
, __alignof__(struct dm_target_io
)) + offsetof(struct dm_target_io
, clone
);
3250 case DM_TYPE_REQUEST_BASED
:
3251 pool_size
= dm_get_reserved_rq_based_ios();
3252 pools
->rq_pool
= mempool_create_slab_pool(pool_size
, _rq_cache
);
3253 if (!pools
->rq_pool
)
3255 /* fall through to setup remaining rq-based pools */
3256 case DM_TYPE_MQ_REQUEST_BASED
:
3257 cachep
= _rq_tio_cache
;
3259 pool_size
= dm_get_reserved_rq_based_ios();
3260 front_pad
= offsetof(struct dm_rq_clone_bio_info
, clone
);
3261 /* per_bio_data_size is not used. See __bind_mempools(). */
3262 WARN_ON(per_bio_data_size
!= 0);
3268 pools
->io_pool
= mempool_create_slab_pool(pool_size
, cachep
);
3269 if (!pools
->io_pool
)
3272 pools
->bs
= bioset_create_nobvec(pool_size
, front_pad
);
3276 if (integrity
&& bioset_integrity_create(pools
->bs
, pool_size
))
3282 dm_free_md_mempools(pools
);
3287 void dm_free_md_mempools(struct dm_md_mempools
*pools
)
3293 mempool_destroy(pools
->io_pool
);
3296 mempool_destroy(pools
->rq_pool
);
3299 bioset_free(pools
->bs
);
3304 static const struct block_device_operations dm_blk_dops
= {
3305 .open
= dm_blk_open
,
3306 .release
= dm_blk_close
,
3307 .ioctl
= dm_blk_ioctl
,
3308 .getgeo
= dm_blk_getgeo
,
3309 .owner
= THIS_MODULE
3315 module_init(dm_init
);
3316 module_exit(dm_exit
);
3318 module_param(major
, uint
, 0);
3319 MODULE_PARM_DESC(major
, "The major number of the device mapper");
3321 module_param(reserved_bio_based_ios
, uint
, S_IRUGO
| S_IWUSR
);
3322 MODULE_PARM_DESC(reserved_bio_based_ios
, "Reserved IOs in bio-based mempools");
3324 module_param(reserved_rq_based_ios
, uint
, S_IRUGO
| S_IWUSR
);
3325 MODULE_PARM_DESC(reserved_rq_based_ios
, "Reserved IOs in request-based mempools");
3327 MODULE_DESCRIPTION(DM_NAME
" driver");
3328 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3329 MODULE_LICENSE("GPL");