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>
22 #include <linux/delay.h>
24 #include <trace/events/block.h>
26 #define DM_MSG_PREFIX "core"
29 * Cookies are numeric values sent with CHANGE and REMOVE
30 * uevents while resuming, removing or renaming the device.
32 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
33 #define DM_COOKIE_LENGTH 24
35 static const char *_name = DM_NAME;
37 static unsigned int major = 0;
38 static unsigned int _major = 0;
40 static DEFINE_SPINLOCK(_minor_lock);
43 * One of these is allocated per bio.
46 struct mapped_device *md;
50 unsigned long start_time;
51 spinlock_t endio_lock;
56 * One of these is allocated per target within a bio. Hopefully
57 * this will be simplified out one day.
66 * For request-based dm.
67 * One of these is allocated per request.
69 struct dm_rq_target_io {
70 struct mapped_device *md;
72 struct request *orig, clone;
78 * For request-based dm.
79 * One of these is allocated per bio.
81 struct dm_rq_clone_bio_info {
83 struct dm_rq_target_io *tio;
86 union map_info *dm_get_mapinfo(struct bio *bio)
88 if (bio && bio->bi_private)
89 return &((struct dm_target_io *)bio->bi_private)->info;
93 union map_info *dm_get_rq_mapinfo(struct request *rq)
95 if (rq && rq->end_io_data)
96 return &((struct dm_rq_target_io *)rq->end_io_data)->info;
99 EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
101 #define MINOR_ALLOCED ((void *)-1)
104 * Bits for the md->flags field.
106 #define DMF_BLOCK_IO_FOR_SUSPEND 0
107 #define DMF_SUSPENDED 1
109 #define DMF_FREEING 3
110 #define DMF_DELETING 4
111 #define DMF_NOFLUSH_SUSPENDING 5
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;
127 /* Protect queue and type against concurrent access. */
128 struct mutex type_lock;
130 struct gendisk *disk;
136 * A list of ios that arrived while we were suspended.
139 wait_queue_head_t wait;
140 struct work_struct work;
141 struct bio_list deferred;
142 spinlock_t deferred_lock;
145 * Processing queue (flush)
147 struct workqueue_struct *wq;
150 * The current mapping.
152 struct dm_table *map;
155 * io objects are allocated from here.
166 wait_queue_head_t eventq;
168 struct list_head uevent_list;
169 spinlock_t uevent_lock; /* Protect access to uevent_list */
172 * freeze/thaw support require holding onto a super block
174 struct super_block *frozen_sb;
175 struct block_device *bdev;
177 /* forced geometry settings */
178 struct hd_geometry geometry;
180 /* For saving the address of __make_request for request based dm */
181 make_request_fn *saved_make_request_fn;
186 /* zero-length flush that will be cloned and submitted to targets */
187 struct bio flush_bio;
191 * For mempools pre-allocation at the table loading time.
193 struct dm_md_mempools {
200 static struct kmem_cache *_io_cache;
201 static struct kmem_cache *_tio_cache;
202 static struct kmem_cache *_rq_tio_cache;
203 static struct kmem_cache *_rq_bio_info_cache;
205 static int __init local_init(void)
209 /* allocate a slab for the dm_ios */
210 _io_cache = KMEM_CACHE(dm_io, 0);
214 /* allocate a slab for the target ios */
215 _tio_cache = KMEM_CACHE(dm_target_io, 0);
217 goto out_free_io_cache;
219 _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
221 goto out_free_tio_cache;
223 _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
224 if (!_rq_bio_info_cache)
225 goto out_free_rq_tio_cache;
227 r = dm_uevent_init();
229 goto out_free_rq_bio_info_cache;
232 r = register_blkdev(_major, _name);
234 goto out_uevent_exit;
243 out_free_rq_bio_info_cache:
244 kmem_cache_destroy(_rq_bio_info_cache);
245 out_free_rq_tio_cache:
246 kmem_cache_destroy(_rq_tio_cache);
248 kmem_cache_destroy(_tio_cache);
250 kmem_cache_destroy(_io_cache);
255 static void local_exit(void)
257 kmem_cache_destroy(_rq_bio_info_cache);
258 kmem_cache_destroy(_rq_tio_cache);
259 kmem_cache_destroy(_tio_cache);
260 kmem_cache_destroy(_io_cache);
261 unregister_blkdev(_major, _name);
266 DMINFO("cleaned up");
269 static int (*_inits[])(void) __initdata = {
279 static void (*_exits[])(void) = {
289 static int __init dm_init(void)
291 const int count = ARRAY_SIZE(_inits);
295 for (i = 0; i < count; i++) {
310 static void __exit dm_exit(void)
312 int i = ARRAY_SIZE(_exits);
319 * Block device functions
321 int dm_deleting_md(struct mapped_device *md)
323 return test_bit(DMF_DELETING, &md->flags);
326 static int dm_blk_open(struct block_device *bdev, fmode_t mode)
328 struct mapped_device *md;
330 spin_lock(&_minor_lock);
332 md = bdev->bd_disk->private_data;
336 if (test_bit(DMF_FREEING, &md->flags) ||
337 dm_deleting_md(md)) {
343 atomic_inc(&md->open_count);
346 spin_unlock(&_minor_lock);
348 return md ? 0 : -ENXIO;
351 static int dm_blk_close(struct gendisk *disk, fmode_t mode)
353 struct mapped_device *md = disk->private_data;
355 spin_lock(&_minor_lock);
357 atomic_dec(&md->open_count);
360 spin_unlock(&_minor_lock);
365 int dm_open_count(struct mapped_device *md)
367 return atomic_read(&md->open_count);
371 * Guarantees nothing is using the device before it's deleted.
373 int dm_lock_for_deletion(struct mapped_device *md)
377 spin_lock(&_minor_lock);
379 if (dm_open_count(md))
382 set_bit(DMF_DELETING, &md->flags);
384 spin_unlock(&_minor_lock);
389 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
391 struct mapped_device *md = bdev->bd_disk->private_data;
393 return dm_get_geometry(md, geo);
396 static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
397 unsigned int cmd, unsigned long arg)
399 struct mapped_device *md = bdev->bd_disk->private_data;
400 struct dm_table *map = dm_get_live_table(md);
401 struct dm_target *tgt;
404 if (!map || !dm_table_get_size(map))
407 /* We only support devices that have a single target */
408 if (dm_table_get_num_targets(map) != 1)
411 tgt = dm_table_get_target(map, 0);
413 if (dm_suspended_md(md)) {
418 if (tgt->type->ioctl)
419 r = tgt->type->ioctl(tgt, cmd, arg);
427 static struct dm_io *alloc_io(struct mapped_device *md)
429 return mempool_alloc(md->io_pool, GFP_NOIO);
432 static void free_io(struct mapped_device *md, struct dm_io *io)
434 mempool_free(io, md->io_pool);
437 static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
439 mempool_free(tio, md->tio_pool);
442 static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
445 return mempool_alloc(md->tio_pool, gfp_mask);
448 static void free_rq_tio(struct dm_rq_target_io *tio)
450 mempool_free(tio, tio->md->tio_pool);
453 static struct dm_rq_clone_bio_info *alloc_bio_info(struct mapped_device *md)
455 return mempool_alloc(md->io_pool, GFP_ATOMIC);
458 static void free_bio_info(struct dm_rq_clone_bio_info *info)
460 mempool_free(info, info->tio->md->io_pool);
463 static int md_in_flight(struct mapped_device *md)
465 return atomic_read(&md->pending[READ]) +
466 atomic_read(&md->pending[WRITE]);
469 static void start_io_acct(struct dm_io *io)
471 struct mapped_device *md = io->md;
473 int rw = bio_data_dir(io->bio);
475 io->start_time = jiffies;
477 cpu = part_stat_lock();
478 part_round_stats(cpu, &dm_disk(md)->part0);
480 dm_disk(md)->part0.in_flight[rw] = atomic_inc_return(&md->pending[rw]);
483 static void end_io_acct(struct dm_io *io)
485 struct mapped_device *md = io->md;
486 struct bio *bio = io->bio;
487 unsigned long duration = jiffies - io->start_time;
489 int rw = bio_data_dir(bio);
491 cpu = part_stat_lock();
492 part_round_stats(cpu, &dm_disk(md)->part0);
493 part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
497 * After this is decremented the bio must not be touched if it is
500 dm_disk(md)->part0.in_flight[rw] = pending =
501 atomic_dec_return(&md->pending[rw]);
502 pending += atomic_read(&md->pending[rw^0x1]);
504 /* nudge anyone waiting on suspend queue */
510 * Add the bio to the list of deferred io.
512 static void queue_io(struct mapped_device *md, struct bio *bio)
516 spin_lock_irqsave(&md->deferred_lock, flags);
517 bio_list_add(&md->deferred, bio);
518 spin_unlock_irqrestore(&md->deferred_lock, flags);
519 queue_work(md->wq, &md->work);
523 * Everyone (including functions in this file), should use this
524 * function to access the md->map field, and make sure they call
525 * dm_table_put() when finished.
527 struct dm_table *dm_get_live_table(struct mapped_device *md)
532 read_lock_irqsave(&md->map_lock, flags);
536 read_unlock_irqrestore(&md->map_lock, flags);
542 * Get the geometry associated with a dm device
544 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
552 * Set the geometry of a device.
554 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
556 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
558 if (geo->start > sz) {
559 DMWARN("Start sector is beyond the geometry limits.");
568 /*-----------------------------------------------------------------
570 * A more elegant soln is in the works that uses the queue
571 * merge fn, unfortunately there are a couple of changes to
572 * the block layer that I want to make for this. So in the
573 * interests of getting something for people to use I give
574 * you this clearly demarcated crap.
575 *---------------------------------------------------------------*/
577 static int __noflush_suspending(struct mapped_device *md)
579 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
583 * Decrements the number of outstanding ios that a bio has been
584 * cloned into, completing the original io if necc.
586 static void dec_pending(struct dm_io *io, int error)
591 struct mapped_device *md = io->md;
593 /* Push-back supersedes any I/O errors */
594 if (unlikely(error)) {
595 spin_lock_irqsave(&io->endio_lock, flags);
596 if (!(io->error > 0 && __noflush_suspending(md)))
598 spin_unlock_irqrestore(&io->endio_lock, flags);
601 if (atomic_dec_and_test(&io->io_count)) {
602 if (io->error == DM_ENDIO_REQUEUE) {
604 * Target requested pushing back the I/O.
606 spin_lock_irqsave(&md->deferred_lock, flags);
607 if (__noflush_suspending(md))
608 bio_list_add_head(&md->deferred, io->bio);
610 /* noflush suspend was interrupted. */
612 spin_unlock_irqrestore(&md->deferred_lock, flags);
615 io_error = io->error;
620 if (io_error == DM_ENDIO_REQUEUE)
623 if ((bio->bi_rw & REQ_FLUSH) && bio->bi_size) {
625 * Preflush done for flush with data, reissue
628 bio->bi_rw &= ~REQ_FLUSH;
631 /* done with normal IO or empty flush */
632 trace_block_bio_complete(md->queue, bio, io_error);
633 bio_endio(bio, io_error);
638 static void clone_endio(struct bio *bio, int error)
641 struct dm_target_io *tio = bio->bi_private;
642 struct dm_io *io = tio->io;
643 struct mapped_device *md = tio->io->md;
644 dm_endio_fn endio = tio->ti->type->end_io;
646 if (!bio_flagged(bio, BIO_UPTODATE) && !error)
650 r = endio(tio->ti, bio, error, &tio->info);
651 if (r < 0 || r == DM_ENDIO_REQUEUE)
653 * error and requeue request are handled
657 else if (r == DM_ENDIO_INCOMPLETE)
658 /* The target will handle the io */
661 DMWARN("unimplemented target endio return value: %d", r);
667 * Store md for cleanup instead of tio which is about to get freed.
669 bio->bi_private = md->bs;
673 dec_pending(io, error);
677 * Partial completion handling for request-based dm
679 static void end_clone_bio(struct bio *clone, int error)
681 struct dm_rq_clone_bio_info *info = clone->bi_private;
682 struct dm_rq_target_io *tio = info->tio;
683 struct bio *bio = info->orig;
684 unsigned int nr_bytes = info->orig->bi_size;
690 * An error has already been detected on the request.
691 * Once error occurred, just let clone->end_io() handle
697 * Don't notice the error to the upper layer yet.
698 * The error handling decision is made by the target driver,
699 * when the request is completed.
706 * I/O for the bio successfully completed.
707 * Notice the data completion to the upper layer.
711 * bios are processed from the head of the list.
712 * So the completing bio should always be rq->bio.
713 * If it's not, something wrong is happening.
715 if (tio->orig->bio != bio)
716 DMERR("bio completion is going in the middle of the request");
719 * Update the original request.
720 * Do not use blk_end_request() here, because it may complete
721 * the original request before the clone, and break the ordering.
723 blk_update_request(tio->orig, 0, nr_bytes);
727 * Don't touch any member of the md after calling this function because
728 * the md may be freed in dm_put() at the end of this function.
729 * Or do dm_get() before calling this function and dm_put() later.
731 static void rq_completed(struct mapped_device *md, int rw, int run_queue)
733 atomic_dec(&md->pending[rw]);
735 /* nudge anyone waiting on suspend queue */
736 if (!md_in_flight(md))
740 blk_run_queue(md->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);
757 * Complete the clone and the original request.
758 * Must be called without queue lock.
760 static void dm_end_request(struct request *clone, int error)
762 int rw = rq_data_dir(clone);
763 struct dm_rq_target_io *tio = clone->end_io_data;
764 struct mapped_device *md = tio->md;
765 struct request *rq = tio->orig;
767 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
768 rq->errors = clone->errors;
769 rq->resid_len = clone->resid_len;
773 * We are using the sense buffer of the original
775 * So setting the length of the sense data is enough.
777 rq->sense_len = clone->sense_len;
780 free_rq_clone(clone);
781 blk_end_request_all(rq, error);
782 rq_completed(md, rw, true);
785 static void dm_unprep_request(struct request *rq)
787 struct request *clone = rq->special;
790 rq->cmd_flags &= ~REQ_DONTPREP;
792 free_rq_clone(clone);
796 * Requeue the original request of a clone.
798 void dm_requeue_unmapped_request(struct request *clone)
800 int rw = rq_data_dir(clone);
801 struct dm_rq_target_io *tio = clone->end_io_data;
802 struct mapped_device *md = tio->md;
803 struct request *rq = tio->orig;
804 struct request_queue *q = rq->q;
807 dm_unprep_request(rq);
809 spin_lock_irqsave(q->queue_lock, flags);
810 blk_requeue_request(q, rq);
811 spin_unlock_irqrestore(q->queue_lock, flags);
813 rq_completed(md, rw, 0);
815 EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request);
817 static void __stop_queue(struct request_queue *q)
822 static void stop_queue(struct request_queue *q)
826 spin_lock_irqsave(q->queue_lock, flags);
828 spin_unlock_irqrestore(q->queue_lock, flags);
831 static void __start_queue(struct request_queue *q)
833 if (blk_queue_stopped(q))
837 static void start_queue(struct request_queue *q)
841 spin_lock_irqsave(q->queue_lock, flags);
843 spin_unlock_irqrestore(q->queue_lock, flags);
846 static void dm_done(struct request *clone, int error, bool mapped)
849 struct dm_rq_target_io *tio = clone->end_io_data;
850 dm_request_endio_fn rq_end_io = tio->ti->type->rq_end_io;
852 if (mapped && rq_end_io)
853 r = rq_end_io(tio->ti, clone, error, &tio->info);
856 /* The target wants to complete the I/O */
857 dm_end_request(clone, r);
858 else if (r == DM_ENDIO_INCOMPLETE)
859 /* The target will handle the I/O */
861 else if (r == DM_ENDIO_REQUEUE)
862 /* The target wants to requeue the I/O */
863 dm_requeue_unmapped_request(clone);
865 DMWARN("unimplemented target endio return value: %d", r);
871 * Request completion handler for request-based dm
873 static void dm_softirq_done(struct request *rq)
876 struct request *clone = rq->completion_data;
877 struct dm_rq_target_io *tio = clone->end_io_data;
879 if (rq->cmd_flags & REQ_FAILED)
882 dm_done(clone, tio->error, mapped);
886 * Complete the clone and the original request with the error status
887 * through softirq context.
889 static void dm_complete_request(struct request *clone, int error)
891 struct dm_rq_target_io *tio = clone->end_io_data;
892 struct request *rq = tio->orig;
895 rq->completion_data = clone;
896 blk_complete_request(rq);
900 * Complete the not-mapped clone and the original request with the error status
901 * through softirq context.
902 * Target's rq_end_io() function isn't called.
903 * This may be used when the target's map_rq() function fails.
905 void dm_kill_unmapped_request(struct request *clone, int error)
907 struct dm_rq_target_io *tio = clone->end_io_data;
908 struct request *rq = tio->orig;
910 rq->cmd_flags |= REQ_FAILED;
911 dm_complete_request(clone, error);
913 EXPORT_SYMBOL_GPL(dm_kill_unmapped_request);
916 * Called with the queue lock held
918 static void end_clone_request(struct request *clone, int error)
921 * For just cleaning up the information of the queue in which
922 * the clone was dispatched.
923 * The clone is *NOT* freed actually here because it is alloced from
924 * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
926 __blk_put_request(clone->q, clone);
929 * Actual request completion is done in a softirq context which doesn't
930 * hold the queue lock. Otherwise, deadlock could occur because:
931 * - another request may be submitted by the upper level driver
932 * of the stacking during the completion
933 * - the submission which requires queue lock may be done
936 dm_complete_request(clone, error);
940 * Return maximum size of I/O possible at the supplied sector up to the current
943 static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
945 sector_t target_offset = dm_target_offset(ti, sector);
947 return ti->len - target_offset;
950 static sector_t max_io_len(sector_t sector, struct dm_target *ti)
952 sector_t len = max_io_len_target_boundary(sector, ti);
955 * Does the target need to split even further ?
959 sector_t offset = dm_target_offset(ti, sector);
960 boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
969 static void __map_bio(struct dm_target *ti, struct bio *clone,
970 struct dm_target_io *tio)
974 struct mapped_device *md;
976 clone->bi_end_io = clone_endio;
977 clone->bi_private = tio;
980 * Map the clone. If r == 0 we don't need to do
981 * anything, the target has assumed ownership of
984 atomic_inc(&tio->io->io_count);
985 sector = clone->bi_sector;
986 r = ti->type->map(ti, clone, &tio->info);
987 if (r == DM_MAPIO_REMAPPED) {
988 /* the bio has been remapped so dispatch it */
990 trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone,
991 tio->io->bio->bi_bdev->bd_dev, sector);
993 generic_make_request(clone);
994 } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
995 /* error the io and bail out, or requeue it if needed */
997 dec_pending(tio->io, r);
999 * Store bio_set for cleanup.
1001 clone->bi_private = md->bs;
1005 DMWARN("unimplemented target map return value: %d", r);
1011 struct mapped_device *md;
1012 struct dm_table *map;
1016 sector_t sector_count;
1020 static void dm_bio_destructor(struct bio *bio)
1022 struct bio_set *bs = bio->bi_private;
1028 * Creates a little bio that just does part of a bvec.
1030 static struct bio *split_bvec(struct bio *bio, sector_t sector,
1031 unsigned short idx, unsigned int offset,
1032 unsigned int len, struct bio_set *bs)
1035 struct bio_vec *bv = bio->bi_io_vec + idx;
1037 clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
1038 clone->bi_destructor = dm_bio_destructor;
1039 *clone->bi_io_vec = *bv;
1041 clone->bi_sector = sector;
1042 clone->bi_bdev = bio->bi_bdev;
1043 clone->bi_rw = bio->bi_rw;
1045 clone->bi_size = to_bytes(len);
1046 clone->bi_io_vec->bv_offset = offset;
1047 clone->bi_io_vec->bv_len = clone->bi_size;
1048 clone->bi_flags |= 1 << BIO_CLONED;
1050 if (bio_integrity(bio)) {
1051 bio_integrity_clone(clone, bio, GFP_NOIO, bs);
1052 bio_integrity_trim(clone,
1053 bio_sector_offset(bio, idx, offset), len);
1060 * Creates a bio that consists of range of complete bvecs.
1062 static struct bio *clone_bio(struct bio *bio, sector_t sector,
1063 unsigned short idx, unsigned short bv_count,
1064 unsigned int len, struct bio_set *bs)
1068 clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
1069 __bio_clone(clone, bio);
1070 clone->bi_destructor = dm_bio_destructor;
1071 clone->bi_sector = sector;
1072 clone->bi_idx = idx;
1073 clone->bi_vcnt = idx + bv_count;
1074 clone->bi_size = to_bytes(len);
1075 clone->bi_flags &= ~(1 << BIO_SEG_VALID);
1077 if (bio_integrity(bio)) {
1078 bio_integrity_clone(clone, bio, GFP_NOIO, bs);
1080 if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
1081 bio_integrity_trim(clone,
1082 bio_sector_offset(bio, idx, 0), len);
1088 static struct dm_target_io *alloc_tio(struct clone_info *ci,
1089 struct dm_target *ti)
1091 struct dm_target_io *tio = mempool_alloc(ci->md->tio_pool, GFP_NOIO);
1095 memset(&tio->info, 0, sizeof(tio->info));
1100 static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
1101 unsigned request_nr, sector_t len)
1103 struct dm_target_io *tio = alloc_tio(ci, ti);
1106 tio->info.target_request_nr = request_nr;
1109 * Discard requests require the bio's inline iovecs be initialized.
1110 * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
1111 * and discard, so no need for concern about wasted bvec allocations.
1113 clone = bio_alloc_bioset(GFP_NOIO, ci->bio->bi_max_vecs, ci->md->bs);
1114 __bio_clone(clone, ci->bio);
1115 clone->bi_destructor = dm_bio_destructor;
1117 clone->bi_sector = ci->sector;
1118 clone->bi_size = to_bytes(len);
1121 __map_bio(ti, clone, tio);
1124 static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti,
1125 unsigned num_requests, sector_t len)
1127 unsigned request_nr;
1129 for (request_nr = 0; request_nr < num_requests; request_nr++)
1130 __issue_target_request(ci, ti, request_nr, len);
1133 static int __clone_and_map_empty_flush(struct clone_info *ci)
1135 unsigned target_nr = 0;
1136 struct dm_target *ti;
1138 BUG_ON(bio_has_data(ci->bio));
1139 while ((ti = dm_table_get_target(ci->map, target_nr++)))
1140 __issue_target_requests(ci, ti, ti->num_flush_requests, 0);
1146 * Perform all io with a single clone.
1148 static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
1150 struct bio *clone, *bio = ci->bio;
1151 struct dm_target_io *tio;
1153 tio = alloc_tio(ci, ti);
1154 clone = clone_bio(bio, ci->sector, ci->idx,
1155 bio->bi_vcnt - ci->idx, ci->sector_count,
1157 __map_bio(ti, clone, tio);
1158 ci->sector_count = 0;
1161 static int __clone_and_map_discard(struct clone_info *ci)
1163 struct dm_target *ti;
1167 ti = dm_table_find_target(ci->map, ci->sector);
1168 if (!dm_target_is_valid(ti))
1172 * Even though the device advertised discard support,
1173 * reconfiguration might have changed that since the
1174 * check was performed.
1176 if (!ti->num_discard_requests)
1179 len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
1181 __issue_target_requests(ci, ti, ti->num_discard_requests, len);
1184 } while (ci->sector_count -= len);
1189 static int __clone_and_map(struct clone_info *ci)
1191 struct bio *clone, *bio = ci->bio;
1192 struct dm_target *ti;
1193 sector_t len = 0, max;
1194 struct dm_target_io *tio;
1196 if (unlikely(bio->bi_rw & REQ_DISCARD))
1197 return __clone_and_map_discard(ci);
1199 ti = dm_table_find_target(ci->map, ci->sector);
1200 if (!dm_target_is_valid(ti))
1203 max = max_io_len(ci->sector, ti);
1205 if (ci->sector_count <= max) {
1207 * Optimise for the simple case where we can do all of
1208 * the remaining io with a single clone.
1210 __clone_and_map_simple(ci, ti);
1212 } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
1214 * There are some bvecs that don't span targets.
1215 * Do as many of these as possible.
1218 sector_t remaining = max;
1221 for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
1222 bv_len = to_sector(bio->bi_io_vec[i].bv_len);
1224 if (bv_len > remaining)
1227 remaining -= bv_len;
1231 tio = alloc_tio(ci, ti);
1232 clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len,
1234 __map_bio(ti, clone, tio);
1237 ci->sector_count -= len;
1242 * Handle a bvec that must be split between two or more targets.
1244 struct bio_vec *bv = bio->bi_io_vec + ci->idx;
1245 sector_t remaining = to_sector(bv->bv_len);
1246 unsigned int offset = 0;
1250 ti = dm_table_find_target(ci->map, ci->sector);
1251 if (!dm_target_is_valid(ti))
1254 max = max_io_len(ci->sector, ti);
1257 len = min(remaining, max);
1259 tio = alloc_tio(ci, ti);
1260 clone = split_bvec(bio, ci->sector, ci->idx,
1261 bv->bv_offset + offset, len,
1264 __map_bio(ti, clone, tio);
1267 ci->sector_count -= len;
1268 offset += to_bytes(len);
1269 } while (remaining -= len);
1278 * Split the bio into several clones and submit it to targets.
1280 static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
1282 struct clone_info ci;
1285 ci.map = dm_get_live_table(md);
1286 if (unlikely(!ci.map)) {
1292 ci.io = alloc_io(md);
1294 atomic_set(&ci.io->io_count, 1);
1297 spin_lock_init(&ci.io->endio_lock);
1298 ci.sector = bio->bi_sector;
1299 ci.idx = bio->bi_idx;
1301 start_io_acct(ci.io);
1302 if (bio->bi_rw & REQ_FLUSH) {
1303 ci.bio = &ci.md->flush_bio;
1304 ci.sector_count = 0;
1305 error = __clone_and_map_empty_flush(&ci);
1306 /* dec_pending submits any data associated with flush */
1309 ci.sector_count = bio_sectors(bio);
1310 while (ci.sector_count && !error)
1311 error = __clone_and_map(&ci);
1314 /* drop the extra reference count */
1315 dec_pending(ci.io, error);
1316 dm_table_put(ci.map);
1318 /*-----------------------------------------------------------------
1320 *---------------------------------------------------------------*/
1322 static int dm_merge_bvec(struct request_queue *q,
1323 struct bvec_merge_data *bvm,
1324 struct bio_vec *biovec)
1326 struct mapped_device *md = q->queuedata;
1327 struct dm_table *map = dm_get_live_table(md);
1328 struct dm_target *ti;
1329 sector_t max_sectors;
1335 ti = dm_table_find_target(map, bvm->bi_sector);
1336 if (!dm_target_is_valid(ti))
1340 * Find maximum amount of I/O that won't need splitting
1342 max_sectors = min(max_io_len(bvm->bi_sector, ti),
1343 (sector_t) BIO_MAX_SECTORS);
1344 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
1349 * merge_bvec_fn() returns number of bytes
1350 * it can accept at this offset
1351 * max is precomputed maximal io size
1353 if (max_size && ti->type->merge)
1354 max_size = ti->type->merge(ti, bvm, biovec, max_size);
1356 * If the target doesn't support merge method and some of the devices
1357 * provided their merge_bvec method (we know this by looking at
1358 * queue_max_hw_sectors), then we can't allow bios with multiple vector
1359 * entries. So always set max_size to 0, and the code below allows
1362 else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
1371 * Always allow an entire first page
1373 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
1374 max_size = biovec->bv_len;
1380 * The request function that just remaps the bio built up by
1383 static int _dm_request(struct request_queue *q, struct bio *bio)
1385 int rw = bio_data_dir(bio);
1386 struct mapped_device *md = q->queuedata;
1389 down_read(&md->io_lock);
1391 cpu = part_stat_lock();
1392 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
1393 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
1396 /* if we're suspended, we have to queue this io for later */
1397 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
1398 up_read(&md->io_lock);
1400 if (bio_rw(bio) != READA)
1407 __split_and_process_bio(md, bio);
1408 up_read(&md->io_lock);
1412 static int dm_make_request(struct request_queue *q, struct bio *bio)
1414 struct mapped_device *md = q->queuedata;
1416 return md->saved_make_request_fn(q, bio); /* call __make_request() */
1419 static int dm_request_based(struct mapped_device *md)
1421 return blk_queue_stackable(md->queue);
1424 static int dm_request(struct request_queue *q, struct bio *bio)
1426 struct mapped_device *md = q->queuedata;
1428 if (dm_request_based(md))
1429 return dm_make_request(q, bio);
1431 return _dm_request(q, bio);
1434 void dm_dispatch_request(struct request *rq)
1438 if (blk_queue_io_stat(rq->q))
1439 rq->cmd_flags |= REQ_IO_STAT;
1441 rq->start_time = jiffies;
1442 r = blk_insert_cloned_request(rq->q, rq);
1444 dm_complete_request(rq, r);
1446 EXPORT_SYMBOL_GPL(dm_dispatch_request);
1448 static void dm_rq_bio_destructor(struct bio *bio)
1450 struct dm_rq_clone_bio_info *info = bio->bi_private;
1451 struct mapped_device *md = info->tio->md;
1453 free_bio_info(info);
1454 bio_free(bio, md->bs);
1457 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
1460 struct dm_rq_target_io *tio = data;
1461 struct mapped_device *md = tio->md;
1462 struct dm_rq_clone_bio_info *info = alloc_bio_info(md);
1467 info->orig = bio_orig;
1469 bio->bi_end_io = end_clone_bio;
1470 bio->bi_private = info;
1471 bio->bi_destructor = dm_rq_bio_destructor;
1476 static int setup_clone(struct request *clone, struct request *rq,
1477 struct dm_rq_target_io *tio)
1481 r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
1482 dm_rq_bio_constructor, tio);
1486 clone->cmd = rq->cmd;
1487 clone->cmd_len = rq->cmd_len;
1488 clone->sense = rq->sense;
1489 clone->buffer = rq->buffer;
1490 clone->end_io = end_clone_request;
1491 clone->end_io_data = tio;
1496 static struct request *clone_rq(struct request *rq, struct mapped_device *md,
1499 struct request *clone;
1500 struct dm_rq_target_io *tio;
1502 tio = alloc_rq_tio(md, gfp_mask);
1510 memset(&tio->info, 0, sizeof(tio->info));
1512 clone = &tio->clone;
1513 if (setup_clone(clone, rq, tio)) {
1523 * Called with the queue lock held.
1525 static int dm_prep_fn(struct request_queue *q, struct request *rq)
1527 struct mapped_device *md = q->queuedata;
1528 struct request *clone;
1530 if (unlikely(rq->special)) {
1531 DMWARN("Already has something in rq->special.");
1532 return BLKPREP_KILL;
1535 clone = clone_rq(rq, md, GFP_ATOMIC);
1537 return BLKPREP_DEFER;
1539 rq->special = clone;
1540 rq->cmd_flags |= REQ_DONTPREP;
1547 * 0 : the request has been processed (not requeued)
1548 * !0 : the request has been requeued
1550 static int map_request(struct dm_target *ti, struct request *clone,
1551 struct mapped_device *md)
1553 int r, requeued = 0;
1554 struct dm_rq_target_io *tio = clone->end_io_data;
1557 * Hold the md reference here for the in-flight I/O.
1558 * We can't rely on the reference count by device opener,
1559 * because the device may be closed during the request completion
1560 * when all bios are completed.
1561 * See the comment in rq_completed() too.
1566 r = ti->type->map_rq(ti, clone, &tio->info);
1568 case DM_MAPIO_SUBMITTED:
1569 /* The target has taken the I/O to submit by itself later */
1571 case DM_MAPIO_REMAPPED:
1572 /* The target has remapped the I/O so dispatch it */
1573 trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
1574 blk_rq_pos(tio->orig));
1575 dm_dispatch_request(clone);
1577 case DM_MAPIO_REQUEUE:
1578 /* The target wants to requeue the I/O */
1579 dm_requeue_unmapped_request(clone);
1584 DMWARN("unimplemented target map return value: %d", r);
1588 /* The target wants to complete the I/O */
1589 dm_kill_unmapped_request(clone, r);
1597 * q->request_fn for request-based dm.
1598 * Called with the queue lock held.
1600 static void dm_request_fn(struct request_queue *q)
1602 struct mapped_device *md = q->queuedata;
1603 struct dm_table *map = dm_get_live_table(md);
1604 struct dm_target *ti;
1605 struct request *rq, *clone;
1609 * For suspend, check blk_queue_stopped() and increment
1610 * ->pending within a single queue_lock not to increment the
1611 * number of in-flight I/Os after the queue is stopped in
1614 while (!blk_queue_stopped(q)) {
1615 rq = blk_peek_request(q);
1619 /* always use block 0 to find the target for flushes for now */
1621 if (!(rq->cmd_flags & REQ_FLUSH))
1622 pos = blk_rq_pos(rq);
1624 ti = dm_table_find_target(map, pos);
1625 BUG_ON(!dm_target_is_valid(ti));
1627 if (ti->type->busy && ti->type->busy(ti))
1630 blk_start_request(rq);
1631 clone = rq->special;
1632 atomic_inc(&md->pending[rq_data_dir(clone)]);
1634 spin_unlock(q->queue_lock);
1635 if (map_request(ti, clone, md))
1638 BUG_ON(!irqs_disabled());
1639 spin_lock(q->queue_lock);
1645 BUG_ON(!irqs_disabled());
1646 spin_lock(q->queue_lock);
1649 blk_delay_queue(q, HZ / 10);
1656 int dm_underlying_device_busy(struct request_queue *q)
1658 return blk_lld_busy(q);
1660 EXPORT_SYMBOL_GPL(dm_underlying_device_busy);
1662 static int dm_lld_busy(struct request_queue *q)
1665 struct mapped_device *md = q->queuedata;
1666 struct dm_table *map = dm_get_live_table(md);
1668 if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))
1671 r = dm_table_any_busy_target(map);
1678 static int dm_any_congested(void *congested_data, int bdi_bits)
1681 struct mapped_device *md = congested_data;
1682 struct dm_table *map;
1684 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
1685 map = dm_get_live_table(md);
1688 * Request-based dm cares about only own queue for
1689 * the query about congestion status of request_queue
1691 if (dm_request_based(md))
1692 r = md->queue->backing_dev_info.state &
1695 r = dm_table_any_congested(map, bdi_bits);
1704 /*-----------------------------------------------------------------
1705 * An IDR is used to keep track of allocated minor numbers.
1706 *---------------------------------------------------------------*/
1707 static DEFINE_IDR(_minor_idr);
1709 static void free_minor(int minor)
1711 spin_lock(&_minor_lock);
1712 idr_remove(&_minor_idr, minor);
1713 spin_unlock(&_minor_lock);
1717 * See if the device with a specific minor # is free.
1719 static int specific_minor(int minor)
1723 if (minor >= (1 << MINORBITS))
1726 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1730 spin_lock(&_minor_lock);
1732 if (idr_find(&_minor_idr, minor)) {
1737 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
1742 idr_remove(&_minor_idr, m);
1748 spin_unlock(&_minor_lock);
1752 static int next_free_minor(int *minor)
1756 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1760 spin_lock(&_minor_lock);
1762 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
1766 if (m >= (1 << MINORBITS)) {
1767 idr_remove(&_minor_idr, m);
1775 spin_unlock(&_minor_lock);
1779 static const struct block_device_operations dm_blk_dops;
1781 static void dm_wq_work(struct work_struct *work);
1783 static void dm_init_md_queue(struct mapped_device *md)
1786 * Request-based dm devices cannot be stacked on top of bio-based dm
1787 * devices. The type of this dm device has not been decided yet.
1788 * The type is decided at the first table loading time.
1789 * To prevent problematic device stacking, clear the queue flag
1790 * for request stacking support until then.
1792 * This queue is new, so no concurrency on the queue_flags.
1794 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
1796 md->queue->queuedata = md;
1797 md->queue->backing_dev_info.congested_fn = dm_any_congested;
1798 md->queue->backing_dev_info.congested_data = md;
1799 blk_queue_make_request(md->queue, dm_request);
1800 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
1801 blk_queue_merge_bvec(md->queue, dm_merge_bvec);
1802 blk_queue_flush(md->queue, REQ_FLUSH | REQ_FUA);
1806 * Allocate and initialise a blank device with a given minor.
1808 static struct mapped_device *alloc_dev(int minor)
1811 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
1815 DMWARN("unable to allocate device, out of memory.");
1819 if (!try_module_get(THIS_MODULE))
1820 goto bad_module_get;
1822 /* get a minor number for the dev */
1823 if (minor == DM_ANY_MINOR)
1824 r = next_free_minor(&minor);
1826 r = specific_minor(minor);
1830 md->type = DM_TYPE_NONE;
1831 init_rwsem(&md->io_lock);
1832 mutex_init(&md->suspend_lock);
1833 mutex_init(&md->type_lock);
1834 spin_lock_init(&md->deferred_lock);
1835 rwlock_init(&md->map_lock);
1836 atomic_set(&md->holders, 1);
1837 atomic_set(&md->open_count, 0);
1838 atomic_set(&md->event_nr, 0);
1839 atomic_set(&md->uevent_seq, 0);
1840 INIT_LIST_HEAD(&md->uevent_list);
1841 spin_lock_init(&md->uevent_lock);
1843 md->queue = blk_alloc_queue(GFP_KERNEL);
1847 dm_init_md_queue(md);
1849 md->disk = alloc_disk(1);
1853 atomic_set(&md->pending[0], 0);
1854 atomic_set(&md->pending[1], 0);
1855 init_waitqueue_head(&md->wait);
1856 INIT_WORK(&md->work, dm_wq_work);
1857 init_waitqueue_head(&md->eventq);
1859 md->disk->major = _major;
1860 md->disk->first_minor = minor;
1861 md->disk->fops = &dm_blk_dops;
1862 md->disk->queue = md->queue;
1863 md->disk->private_data = md;
1864 sprintf(md->disk->disk_name, "dm-%d", minor);
1866 format_dev_t(md->name, MKDEV(_major, minor));
1868 md->wq = alloc_workqueue("kdmflush",
1869 WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
1873 md->bdev = bdget_disk(md->disk, 0);
1877 bio_init(&md->flush_bio);
1878 md->flush_bio.bi_bdev = md->bdev;
1879 md->flush_bio.bi_rw = WRITE_FLUSH;
1881 /* Populate the mapping, nobody knows we exist yet */
1882 spin_lock(&_minor_lock);
1883 old_md = idr_replace(&_minor_idr, md, minor);
1884 spin_unlock(&_minor_lock);
1886 BUG_ON(old_md != MINOR_ALLOCED);
1891 destroy_workqueue(md->wq);
1893 del_gendisk(md->disk);
1896 blk_cleanup_queue(md->queue);
1900 module_put(THIS_MODULE);
1906 static void unlock_fs(struct mapped_device *md);
1908 static void free_dev(struct mapped_device *md)
1910 int minor = MINOR(disk_devt(md->disk));
1914 destroy_workqueue(md->wq);
1916 mempool_destroy(md->tio_pool);
1918 mempool_destroy(md->io_pool);
1920 bioset_free(md->bs);
1921 blk_integrity_unregister(md->disk);
1922 del_gendisk(md->disk);
1925 spin_lock(&_minor_lock);
1926 md->disk->private_data = NULL;
1927 spin_unlock(&_minor_lock);
1930 blk_cleanup_queue(md->queue);
1931 module_put(THIS_MODULE);
1935 static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
1937 struct dm_md_mempools *p;
1939 if (md->io_pool && md->tio_pool && md->bs)
1940 /* the md already has necessary mempools */
1943 p = dm_table_get_md_mempools(t);
1944 BUG_ON(!p || md->io_pool || md->tio_pool || md->bs);
1946 md->io_pool = p->io_pool;
1948 md->tio_pool = p->tio_pool;
1954 /* mempool bind completed, now no need any mempools in the table */
1955 dm_table_free_md_mempools(t);
1959 * Bind a table to the device.
1961 static void event_callback(void *context)
1963 unsigned long flags;
1965 struct mapped_device *md = (struct mapped_device *) context;
1967 spin_lock_irqsave(&md->uevent_lock, flags);
1968 list_splice_init(&md->uevent_list, &uevents);
1969 spin_unlock_irqrestore(&md->uevent_lock, flags);
1971 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
1973 atomic_inc(&md->event_nr);
1974 wake_up(&md->eventq);
1978 * Protected by md->suspend_lock obtained by dm_swap_table().
1980 static void __set_size(struct mapped_device *md, sector_t size)
1982 set_capacity(md->disk, size);
1984 i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
1988 * Returns old map, which caller must destroy.
1990 static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
1991 struct queue_limits *limits)
1993 struct dm_table *old_map;
1994 struct request_queue *q = md->queue;
1996 unsigned long flags;
1998 size = dm_table_get_size(t);
2001 * Wipe any geometry if the size of the table changed.
2003 if (size != get_capacity(md->disk))
2004 memset(&md->geometry, 0, sizeof(md->geometry));
2006 __set_size(md, size);
2008 dm_table_event_callback(t, event_callback, md);
2011 * The queue hasn't been stopped yet, if the old table type wasn't
2012 * for request-based during suspension. So stop it to prevent
2013 * I/O mapping before resume.
2014 * This must be done before setting the queue restrictions,
2015 * because request-based dm may be run just after the setting.
2017 if (dm_table_request_based(t) && !blk_queue_stopped(q))
2020 __bind_mempools(md, t);
2022 write_lock_irqsave(&md->map_lock, flags);
2025 dm_table_set_restrictions(t, q, limits);
2026 write_unlock_irqrestore(&md->map_lock, flags);
2032 * Returns unbound table for the caller to free.
2034 static struct dm_table *__unbind(struct mapped_device *md)
2036 struct dm_table *map = md->map;
2037 unsigned long flags;
2042 dm_table_event_callback(map, NULL, NULL);
2043 write_lock_irqsave(&md->map_lock, flags);
2045 write_unlock_irqrestore(&md->map_lock, flags);
2051 * Constructor for a new device.
2053 int dm_create(int minor, struct mapped_device **result)
2055 struct mapped_device *md;
2057 md = alloc_dev(minor);
2068 * Functions to manage md->type.
2069 * All are required to hold md->type_lock.
2071 void dm_lock_md_type(struct mapped_device *md)
2073 mutex_lock(&md->type_lock);
2076 void dm_unlock_md_type(struct mapped_device *md)
2078 mutex_unlock(&md->type_lock);
2081 void dm_set_md_type(struct mapped_device *md, unsigned type)
2086 unsigned dm_get_md_type(struct mapped_device *md)
2092 * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
2094 static int dm_init_request_based_queue(struct mapped_device *md)
2096 struct request_queue *q = NULL;
2098 if (md->queue->elevator)
2101 /* Fully initialize the queue */
2102 q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL);
2107 md->saved_make_request_fn = md->queue->make_request_fn;
2108 dm_init_md_queue(md);
2109 blk_queue_softirq_done(md->queue, dm_softirq_done);
2110 blk_queue_prep_rq(md->queue, dm_prep_fn);
2111 blk_queue_lld_busy(md->queue, dm_lld_busy);
2113 elv_register_queue(md->queue);
2119 * Setup the DM device's queue based on md's type
2121 int dm_setup_md_queue(struct mapped_device *md)
2123 if ((dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) &&
2124 !dm_init_request_based_queue(md)) {
2125 DMWARN("Cannot initialize queue for request-based mapped device");
2132 static struct mapped_device *dm_find_md(dev_t dev)
2134 struct mapped_device *md;
2135 unsigned minor = MINOR(dev);
2137 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
2140 spin_lock(&_minor_lock);
2142 md = idr_find(&_minor_idr, minor);
2143 if (md && (md == MINOR_ALLOCED ||
2144 (MINOR(disk_devt(dm_disk(md))) != minor) ||
2145 dm_deleting_md(md) ||
2146 test_bit(DMF_FREEING, &md->flags))) {
2152 spin_unlock(&_minor_lock);
2157 struct mapped_device *dm_get_md(dev_t dev)
2159 struct mapped_device *md = dm_find_md(dev);
2167 void *dm_get_mdptr(struct mapped_device *md)
2169 return md->interface_ptr;
2172 void dm_set_mdptr(struct mapped_device *md, void *ptr)
2174 md->interface_ptr = ptr;
2177 void dm_get(struct mapped_device *md)
2179 atomic_inc(&md->holders);
2180 BUG_ON(test_bit(DMF_FREEING, &md->flags));
2183 const char *dm_device_name(struct mapped_device *md)
2187 EXPORT_SYMBOL_GPL(dm_device_name);
2189 static void __dm_destroy(struct mapped_device *md, bool wait)
2191 struct dm_table *map;
2195 spin_lock(&_minor_lock);
2196 map = dm_get_live_table(md);
2197 idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
2198 set_bit(DMF_FREEING, &md->flags);
2199 spin_unlock(&_minor_lock);
2201 if (!dm_suspended_md(md)) {
2202 dm_table_presuspend_targets(map);
2203 dm_table_postsuspend_targets(map);
2207 * Rare, but there may be I/O requests still going to complete,
2208 * for example. Wait for all references to disappear.
2209 * No one should increment the reference count of the mapped_device,
2210 * after the mapped_device state becomes DMF_FREEING.
2213 while (atomic_read(&md->holders))
2215 else if (atomic_read(&md->holders))
2216 DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
2217 dm_device_name(md), atomic_read(&md->holders));
2221 dm_table_destroy(__unbind(md));
2225 void dm_destroy(struct mapped_device *md)
2227 __dm_destroy(md, true);
2230 void dm_destroy_immediate(struct mapped_device *md)
2232 __dm_destroy(md, false);
2235 void dm_put(struct mapped_device *md)
2237 atomic_dec(&md->holders);
2239 EXPORT_SYMBOL_GPL(dm_put);
2241 static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
2244 DECLARE_WAITQUEUE(wait, current);
2246 add_wait_queue(&md->wait, &wait);
2249 set_current_state(interruptible);
2252 if (!md_in_flight(md))
2255 if (interruptible == TASK_INTERRUPTIBLE &&
2256 signal_pending(current)) {
2263 set_current_state(TASK_RUNNING);
2265 remove_wait_queue(&md->wait, &wait);
2271 * Process the deferred bios
2273 static void dm_wq_work(struct work_struct *work)
2275 struct mapped_device *md = container_of(work, struct mapped_device,
2279 down_read(&md->io_lock);
2281 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
2282 spin_lock_irq(&md->deferred_lock);
2283 c = bio_list_pop(&md->deferred);
2284 spin_unlock_irq(&md->deferred_lock);
2289 up_read(&md->io_lock);
2291 if (dm_request_based(md))
2292 generic_make_request(c);
2294 __split_and_process_bio(md, c);
2296 down_read(&md->io_lock);
2299 up_read(&md->io_lock);
2302 static void dm_queue_flush(struct mapped_device *md)
2304 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2305 smp_mb__after_clear_bit();
2306 queue_work(md->wq, &md->work);
2310 * Swap in a new table, returning the old one for the caller to destroy.
2312 struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
2314 struct dm_table *map = ERR_PTR(-EINVAL);
2315 struct queue_limits limits;
2318 mutex_lock(&md->suspend_lock);
2320 /* device must be suspended */
2321 if (!dm_suspended_md(md))
2324 r = dm_calculate_queue_limits(table, &limits);
2330 map = __bind(md, table, &limits);
2333 mutex_unlock(&md->suspend_lock);
2338 * Functions to lock and unlock any filesystem running on the
2341 static int lock_fs(struct mapped_device *md)
2345 WARN_ON(md->frozen_sb);
2347 md->frozen_sb = freeze_bdev(md->bdev);
2348 if (IS_ERR(md->frozen_sb)) {
2349 r = PTR_ERR(md->frozen_sb);
2350 md->frozen_sb = NULL;
2354 set_bit(DMF_FROZEN, &md->flags);
2359 static void unlock_fs(struct mapped_device *md)
2361 if (!test_bit(DMF_FROZEN, &md->flags))
2364 thaw_bdev(md->bdev, md->frozen_sb);
2365 md->frozen_sb = NULL;
2366 clear_bit(DMF_FROZEN, &md->flags);
2370 * We need to be able to change a mapping table under a mounted
2371 * filesystem. For example we might want to move some data in
2372 * the background. Before the table can be swapped with
2373 * dm_bind_table, dm_suspend must be called to flush any in
2374 * flight bios and ensure that any further io gets deferred.
2377 * Suspend mechanism in request-based dm.
2379 * 1. Flush all I/Os by lock_fs() if needed.
2380 * 2. Stop dispatching any I/O by stopping the request_queue.
2381 * 3. Wait for all in-flight I/Os to be completed or requeued.
2383 * To abort suspend, start the request_queue.
2385 int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
2387 struct dm_table *map = NULL;
2389 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
2390 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
2392 mutex_lock(&md->suspend_lock);
2394 if (dm_suspended_md(md)) {
2399 map = dm_get_live_table(md);
2402 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2403 * This flag is cleared before dm_suspend returns.
2406 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2408 /* This does not get reverted if there's an error later. */
2409 dm_table_presuspend_targets(map);
2412 * Flush I/O to the device.
2413 * Any I/O submitted after lock_fs() may not be flushed.
2414 * noflush takes precedence over do_lockfs.
2415 * (lock_fs() flushes I/Os and waits for them to complete.)
2417 if (!noflush && do_lockfs) {
2424 * Here we must make sure that no processes are submitting requests
2425 * to target drivers i.e. no one may be executing
2426 * __split_and_process_bio. This is called from dm_request and
2429 * To get all processes out of __split_and_process_bio in dm_request,
2430 * we take the write lock. To prevent any process from reentering
2431 * __split_and_process_bio from dm_request and quiesce the thread
2432 * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
2433 * flush_workqueue(md->wq).
2435 down_write(&md->io_lock);
2436 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2437 up_write(&md->io_lock);
2440 * Stop md->queue before flushing md->wq in case request-based
2441 * dm defers requests to md->wq from md->queue.
2443 if (dm_request_based(md))
2444 stop_queue(md->queue);
2446 flush_workqueue(md->wq);
2449 * At this point no more requests are entering target request routines.
2450 * We call dm_wait_for_completion to wait for all existing requests
2453 r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
2455 down_write(&md->io_lock);
2457 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2458 up_write(&md->io_lock);
2460 /* were we interrupted ? */
2464 if (dm_request_based(md))
2465 start_queue(md->queue);
2468 goto out; /* pushback list is already flushed, so skip flush */
2472 * If dm_wait_for_completion returned 0, the device is completely
2473 * quiescent now. There is no request-processing activity. All new
2474 * requests are being added to md->deferred list.
2477 set_bit(DMF_SUSPENDED, &md->flags);
2479 dm_table_postsuspend_targets(map);
2485 mutex_unlock(&md->suspend_lock);
2489 int dm_resume(struct mapped_device *md)
2492 struct dm_table *map = NULL;
2494 mutex_lock(&md->suspend_lock);
2495 if (!dm_suspended_md(md))
2498 map = dm_get_live_table(md);
2499 if (!map || !dm_table_get_size(map))
2502 r = dm_table_resume_targets(map);
2509 * Flushing deferred I/Os must be done after targets are resumed
2510 * so that mapping of targets can work correctly.
2511 * Request-based dm is queueing the deferred I/Os in its request_queue.
2513 if (dm_request_based(md))
2514 start_queue(md->queue);
2518 clear_bit(DMF_SUSPENDED, &md->flags);
2523 mutex_unlock(&md->suspend_lock);
2528 /*-----------------------------------------------------------------
2529 * Event notification.
2530 *---------------------------------------------------------------*/
2531 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
2534 char udev_cookie[DM_COOKIE_LENGTH];
2535 char *envp[] = { udev_cookie, NULL };
2538 return kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
2540 snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
2541 DM_COOKIE_ENV_VAR_NAME, cookie);
2542 return kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
2547 uint32_t dm_next_uevent_seq(struct mapped_device *md)
2549 return atomic_add_return(1, &md->uevent_seq);
2552 uint32_t dm_get_event_nr(struct mapped_device *md)
2554 return atomic_read(&md->event_nr);
2557 int dm_wait_event(struct mapped_device *md, int event_nr)
2559 return wait_event_interruptible(md->eventq,
2560 (event_nr != atomic_read(&md->event_nr)));
2563 void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
2565 unsigned long flags;
2567 spin_lock_irqsave(&md->uevent_lock, flags);
2568 list_add(elist, &md->uevent_list);
2569 spin_unlock_irqrestore(&md->uevent_lock, flags);
2573 * The gendisk is only valid as long as you have a reference
2576 struct gendisk *dm_disk(struct mapped_device *md)
2581 struct kobject *dm_kobject(struct mapped_device *md)
2587 * struct mapped_device should not be exported outside of dm.c
2588 * so use this check to verify that kobj is part of md structure
2590 struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
2592 struct mapped_device *md;
2594 md = container_of(kobj, struct mapped_device, kobj);
2595 if (&md->kobj != kobj)
2598 if (test_bit(DMF_FREEING, &md->flags) ||
2606 int dm_suspended_md(struct mapped_device *md)
2608 return test_bit(DMF_SUSPENDED, &md->flags);
2611 int dm_suspended(struct dm_target *ti)
2613 return dm_suspended_md(dm_table_get_md(ti->table));
2615 EXPORT_SYMBOL_GPL(dm_suspended);
2617 int dm_noflush_suspending(struct dm_target *ti)
2619 return __noflush_suspending(dm_table_get_md(ti->table));
2621 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
2623 struct dm_md_mempools *dm_alloc_md_mempools(unsigned type)
2625 struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL);
2630 pools->io_pool = (type == DM_TYPE_BIO_BASED) ?
2631 mempool_create_slab_pool(MIN_IOS, _io_cache) :
2632 mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache);
2633 if (!pools->io_pool)
2634 goto free_pools_and_out;
2636 pools->tio_pool = (type == DM_TYPE_BIO_BASED) ?
2637 mempool_create_slab_pool(MIN_IOS, _tio_cache) :
2638 mempool_create_slab_pool(MIN_IOS, _rq_tio_cache);
2639 if (!pools->tio_pool)
2640 goto free_io_pool_and_out;
2642 pools->bs = (type == DM_TYPE_BIO_BASED) ?
2643 bioset_create(16, 0) : bioset_create(MIN_IOS, 0);
2645 goto free_tio_pool_and_out;
2649 free_tio_pool_and_out:
2650 mempool_destroy(pools->tio_pool);
2652 free_io_pool_and_out:
2653 mempool_destroy(pools->io_pool);
2661 void dm_free_md_mempools(struct dm_md_mempools *pools)
2667 mempool_destroy(pools->io_pool);
2669 if (pools->tio_pool)
2670 mempool_destroy(pools->tio_pool);
2673 bioset_free(pools->bs);
2678 static const struct block_device_operations dm_blk_dops = {
2679 .open = dm_blk_open,
2680 .release = dm_blk_close,
2681 .ioctl = dm_blk_ioctl,
2682 .getgeo = dm_blk_getgeo,
2683 .owner = THIS_MODULE
2686 EXPORT_SYMBOL(dm_get_mapinfo);
2691 module_init(dm_init);
2692 module_exit(dm_exit);
2694 module_param(major, uint, 0);
2695 MODULE_PARM_DESC(major, "The major number of the device mapper");
2696 MODULE_DESCRIPTION(DM_NAME " driver");
2697 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2698 MODULE_LICENSE("GPL");