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>
23 #include <trace/events/block.h>
25 #define DM_MSG_PREFIX "core"
29 * ratelimit state to be used in DMXXX_LIMIT().
31 DEFINE_RATELIMIT_STATE(dm_ratelimit_state,
32 DEFAULT_RATELIMIT_INTERVAL,
33 DEFAULT_RATELIMIT_BURST);
34 EXPORT_SYMBOL(dm_ratelimit_state);
38 * Cookies are numeric values sent with CHANGE and REMOVE
39 * uevents while resuming, removing or renaming the device.
41 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
42 #define DM_COOKIE_LENGTH 24
44 static const char *_name = DM_NAME;
46 static unsigned int major = 0;
47 static unsigned int _major = 0;
49 static DEFINE_IDR(_minor_idr);
51 static DEFINE_SPINLOCK(_minor_lock);
54 * One of these is allocated per bio.
57 struct mapped_device *md;
61 unsigned long start_time;
62 spinlock_t endio_lock;
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 - the bio clones we allocate are embedded in these
81 * We allocate these with bio_alloc_bioset, using the front_pad parameter when
82 * the bioset is created - this means the bio has to come at the end of the
85 struct dm_rq_clone_bio_info {
87 struct dm_rq_target_io *tio;
91 union map_info *dm_get_mapinfo(struct bio *bio)
93 if (bio && bio->bi_private)
94 return &((struct dm_target_io *)bio->bi_private)->info;
98 union map_info *dm_get_rq_mapinfo(struct request *rq)
100 if (rq && rq->end_io_data)
101 return &((struct dm_rq_target_io *)rq->end_io_data)->info;
104 EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
106 #define MINOR_ALLOCED ((void *)-1)
109 * Bits for the md->flags field.
111 #define DMF_BLOCK_IO_FOR_SUSPEND 0
112 #define DMF_SUSPENDED 1
114 #define DMF_FREEING 3
115 #define DMF_DELETING 4
116 #define DMF_NOFLUSH_SUSPENDING 5
117 #define DMF_MERGE_IS_OPTIONAL 6
120 * Work processed by per-device workqueue.
122 struct mapped_device {
123 struct rw_semaphore io_lock;
124 struct mutex suspend_lock;
131 struct request_queue *queue;
133 /* Protect queue and type against concurrent access. */
134 struct mutex type_lock;
136 struct target_type *immutable_target_type;
138 struct gendisk *disk;
144 * A list of ios that arrived while we were suspended.
147 wait_queue_head_t wait;
148 struct work_struct work;
149 struct bio_list deferred;
150 spinlock_t deferred_lock;
153 * Processing queue (flush)
155 struct workqueue_struct *wq;
158 * The current mapping.
160 struct dm_table *map;
163 * io objects are allocated from here.
173 wait_queue_head_t eventq;
175 struct list_head uevent_list;
176 spinlock_t uevent_lock; /* Protect access to uevent_list */
179 * freeze/thaw support require holding onto a super block
181 struct super_block *frozen_sb;
182 struct block_device *bdev;
184 /* forced geometry settings */
185 struct hd_geometry geometry;
190 /* zero-length flush that will be cloned and submitted to targets */
191 struct bio flush_bio;
195 * For mempools pre-allocation at the table loading time.
197 struct dm_md_mempools {
203 static struct kmem_cache *_io_cache;
204 static struct kmem_cache *_rq_tio_cache;
206 static int __init local_init(void)
210 /* allocate a slab for the dm_ios */
211 _io_cache = KMEM_CACHE(dm_io, 0);
215 _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
217 goto out_free_io_cache;
219 r = dm_uevent_init();
221 goto out_free_rq_tio_cache;
224 r = register_blkdev(_major, _name);
226 goto out_uevent_exit;
235 out_free_rq_tio_cache:
236 kmem_cache_destroy(_rq_tio_cache);
238 kmem_cache_destroy(_io_cache);
243 static void local_exit(void)
245 kmem_cache_destroy(_rq_tio_cache);
246 kmem_cache_destroy(_io_cache);
247 unregister_blkdev(_major, _name);
252 DMINFO("cleaned up");
255 static int (*_inits[])(void) __initdata = {
265 static void (*_exits[])(void) = {
275 static int __init dm_init(void)
277 const int count = ARRAY_SIZE(_inits);
281 for (i = 0; i < count; i++) {
296 static void __exit dm_exit(void)
298 int i = ARRAY_SIZE(_exits);
304 * Should be empty by this point.
306 idr_destroy(&_minor_idr);
310 * Block device functions
312 int dm_deleting_md(struct mapped_device *md)
314 return test_bit(DMF_DELETING, &md->flags);
317 static int dm_blk_open(struct block_device *bdev, fmode_t mode)
319 struct mapped_device *md;
321 spin_lock(&_minor_lock);
323 md = bdev->bd_disk->private_data;
327 if (test_bit(DMF_FREEING, &md->flags) ||
328 dm_deleting_md(md)) {
334 atomic_inc(&md->open_count);
337 spin_unlock(&_minor_lock);
339 return md ? 0 : -ENXIO;
342 static int dm_blk_close(struct gendisk *disk, fmode_t mode)
344 struct mapped_device *md = disk->private_data;
346 spin_lock(&_minor_lock);
348 atomic_dec(&md->open_count);
351 spin_unlock(&_minor_lock);
356 int dm_open_count(struct mapped_device *md)
358 return atomic_read(&md->open_count);
362 * Guarantees nothing is using the device before it's deleted.
364 int dm_lock_for_deletion(struct mapped_device *md)
368 spin_lock(&_minor_lock);
370 if (dm_open_count(md))
373 set_bit(DMF_DELETING, &md->flags);
375 spin_unlock(&_minor_lock);
380 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
382 struct mapped_device *md = bdev->bd_disk->private_data;
384 return dm_get_geometry(md, geo);
387 static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
388 unsigned int cmd, unsigned long arg)
390 struct mapped_device *md = bdev->bd_disk->private_data;
391 struct dm_table *map = dm_get_live_table(md);
392 struct dm_target *tgt;
395 if (!map || !dm_table_get_size(map))
398 /* We only support devices that have a single target */
399 if (dm_table_get_num_targets(map) != 1)
402 tgt = dm_table_get_target(map, 0);
404 if (dm_suspended_md(md)) {
409 if (tgt->type->ioctl)
410 r = tgt->type->ioctl(tgt, cmd, arg);
418 static struct dm_io *alloc_io(struct mapped_device *md)
420 return mempool_alloc(md->io_pool, GFP_NOIO);
423 static void free_io(struct mapped_device *md, struct dm_io *io)
425 mempool_free(io, md->io_pool);
428 static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
430 bio_put(&tio->clone);
433 static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
436 return mempool_alloc(md->io_pool, gfp_mask);
439 static void free_rq_tio(struct dm_rq_target_io *tio)
441 mempool_free(tio, tio->md->io_pool);
444 static int md_in_flight(struct mapped_device *md)
446 return atomic_read(&md->pending[READ]) +
447 atomic_read(&md->pending[WRITE]);
450 static void start_io_acct(struct dm_io *io)
452 struct mapped_device *md = io->md;
454 int rw = bio_data_dir(io->bio);
456 io->start_time = jiffies;
458 cpu = part_stat_lock();
459 part_round_stats(cpu, &dm_disk(md)->part0);
461 atomic_set(&dm_disk(md)->part0.in_flight[rw],
462 atomic_inc_return(&md->pending[rw]));
465 static void end_io_acct(struct dm_io *io)
467 struct mapped_device *md = io->md;
468 struct bio *bio = io->bio;
469 unsigned long duration = jiffies - io->start_time;
471 int rw = bio_data_dir(bio);
473 cpu = part_stat_lock();
474 part_round_stats(cpu, &dm_disk(md)->part0);
475 part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
479 * After this is decremented the bio must not be touched if it is
482 pending = atomic_dec_return(&md->pending[rw]);
483 atomic_set(&dm_disk(md)->part0.in_flight[rw], pending);
484 pending += atomic_read(&md->pending[rw^0x1]);
486 /* nudge anyone waiting on suspend queue */
492 * Add the bio to the list of deferred io.
494 static void queue_io(struct mapped_device *md, struct bio *bio)
498 spin_lock_irqsave(&md->deferred_lock, flags);
499 bio_list_add(&md->deferred, bio);
500 spin_unlock_irqrestore(&md->deferred_lock, flags);
501 queue_work(md->wq, &md->work);
505 * Everyone (including functions in this file), should use this
506 * function to access the md->map field, and make sure they call
507 * dm_table_put() when finished.
509 struct dm_table *dm_get_live_table(struct mapped_device *md)
514 read_lock_irqsave(&md->map_lock, flags);
518 read_unlock_irqrestore(&md->map_lock, flags);
524 * Get the geometry associated with a dm device
526 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
534 * Set the geometry of a device.
536 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
538 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
540 if (geo->start > sz) {
541 DMWARN("Start sector is beyond the geometry limits.");
550 /*-----------------------------------------------------------------
552 * A more elegant soln is in the works that uses the queue
553 * merge fn, unfortunately there are a couple of changes to
554 * the block layer that I want to make for this. So in the
555 * interests of getting something for people to use I give
556 * you this clearly demarcated crap.
557 *---------------------------------------------------------------*/
559 static int __noflush_suspending(struct mapped_device *md)
561 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
565 * Decrements the number of outstanding ios that a bio has been
566 * cloned into, completing the original io if necc.
568 static void dec_pending(struct dm_io *io, int error)
573 struct mapped_device *md = io->md;
575 /* Push-back supersedes any I/O errors */
576 if (unlikely(error)) {
577 spin_lock_irqsave(&io->endio_lock, flags);
578 if (!(io->error > 0 && __noflush_suspending(md)))
580 spin_unlock_irqrestore(&io->endio_lock, flags);
583 if (atomic_dec_and_test(&io->io_count)) {
584 if (io->error == DM_ENDIO_REQUEUE) {
586 * Target requested pushing back the I/O.
588 spin_lock_irqsave(&md->deferred_lock, flags);
589 if (__noflush_suspending(md))
590 bio_list_add_head(&md->deferred, io->bio);
592 /* noflush suspend was interrupted. */
594 spin_unlock_irqrestore(&md->deferred_lock, flags);
597 io_error = io->error;
602 if (io_error == DM_ENDIO_REQUEUE)
605 if ((bio->bi_rw & REQ_FLUSH) && bio->bi_size) {
607 * Preflush done for flush with data, reissue
610 bio->bi_rw &= ~REQ_FLUSH;
613 /* done with normal IO or empty flush */
614 trace_block_bio_complete(md->queue, bio, io_error);
615 bio_endio(bio, io_error);
620 static void clone_endio(struct bio *bio, int error)
623 struct dm_target_io *tio = bio->bi_private;
624 struct dm_io *io = tio->io;
625 struct mapped_device *md = tio->io->md;
626 dm_endio_fn endio = tio->ti->type->end_io;
628 if (!bio_flagged(bio, BIO_UPTODATE) && !error)
632 r = endio(tio->ti, bio, error);
633 if (r < 0 || r == DM_ENDIO_REQUEUE)
635 * error and requeue request are handled
639 else if (r == DM_ENDIO_INCOMPLETE)
640 /* The target will handle the io */
643 DMWARN("unimplemented target endio return value: %d", r);
649 dec_pending(io, error);
653 * Partial completion handling for request-based dm
655 static void end_clone_bio(struct bio *clone, int error)
657 struct dm_rq_clone_bio_info *info = clone->bi_private;
658 struct dm_rq_target_io *tio = info->tio;
659 struct bio *bio = info->orig;
660 unsigned int nr_bytes = info->orig->bi_size;
666 * An error has already been detected on the request.
667 * Once error occurred, just let clone->end_io() handle
673 * Don't notice the error to the upper layer yet.
674 * The error handling decision is made by the target driver,
675 * when the request is completed.
682 * I/O for the bio successfully completed.
683 * Notice the data completion to the upper layer.
687 * bios are processed from the head of the list.
688 * So the completing bio should always be rq->bio.
689 * If it's not, something wrong is happening.
691 if (tio->orig->bio != bio)
692 DMERR("bio completion is going in the middle of the request");
695 * Update the original request.
696 * Do not use blk_end_request() here, because it may complete
697 * the original request before the clone, and break the ordering.
699 blk_update_request(tio->orig, 0, nr_bytes);
703 * Don't touch any member of the md after calling this function because
704 * the md may be freed in dm_put() at the end of this function.
705 * Or do dm_get() before calling this function and dm_put() later.
707 static void rq_completed(struct mapped_device *md, int rw, int run_queue)
709 atomic_dec(&md->pending[rw]);
711 /* nudge anyone waiting on suspend queue */
712 if (!md_in_flight(md))
716 * Run this off this callpath, as drivers could invoke end_io while
717 * inside their request_fn (and holding the queue lock). Calling
718 * back into ->request_fn() could deadlock attempting to grab the
722 blk_run_queue_async(md->queue);
725 * dm_put() must be at the end of this function. See the comment above
730 static void free_rq_clone(struct request *clone)
732 struct dm_rq_target_io *tio = clone->end_io_data;
734 blk_rq_unprep_clone(clone);
739 * Complete the clone and the original request.
740 * Must be called without queue lock.
742 static void dm_end_request(struct request *clone, int error)
744 int rw = rq_data_dir(clone);
745 struct dm_rq_target_io *tio = clone->end_io_data;
746 struct mapped_device *md = tio->md;
747 struct request *rq = tio->orig;
749 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
750 rq->errors = clone->errors;
751 rq->resid_len = clone->resid_len;
755 * We are using the sense buffer of the original
757 * So setting the length of the sense data is enough.
759 rq->sense_len = clone->sense_len;
762 free_rq_clone(clone);
763 blk_end_request_all(rq, error);
764 rq_completed(md, rw, true);
767 static void dm_unprep_request(struct request *rq)
769 struct request *clone = rq->special;
772 rq->cmd_flags &= ~REQ_DONTPREP;
774 free_rq_clone(clone);
778 * Requeue the original request of a clone.
780 void dm_requeue_unmapped_request(struct request *clone)
782 int rw = rq_data_dir(clone);
783 struct dm_rq_target_io *tio = clone->end_io_data;
784 struct mapped_device *md = tio->md;
785 struct request *rq = tio->orig;
786 struct request_queue *q = rq->q;
789 dm_unprep_request(rq);
791 spin_lock_irqsave(q->queue_lock, flags);
792 blk_requeue_request(q, rq);
793 spin_unlock_irqrestore(q->queue_lock, flags);
795 rq_completed(md, rw, 0);
797 EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request);
799 static void __stop_queue(struct request_queue *q)
804 static void stop_queue(struct request_queue *q)
808 spin_lock_irqsave(q->queue_lock, flags);
810 spin_unlock_irqrestore(q->queue_lock, flags);
813 static void __start_queue(struct request_queue *q)
815 if (blk_queue_stopped(q))
819 static void start_queue(struct request_queue *q)
823 spin_lock_irqsave(q->queue_lock, flags);
825 spin_unlock_irqrestore(q->queue_lock, flags);
828 static void dm_done(struct request *clone, int error, bool mapped)
831 struct dm_rq_target_io *tio = clone->end_io_data;
832 dm_request_endio_fn rq_end_io = NULL;
835 rq_end_io = tio->ti->type->rq_end_io;
837 if (mapped && rq_end_io)
838 r = rq_end_io(tio->ti, clone, error, &tio->info);
842 /* The target wants to complete the I/O */
843 dm_end_request(clone, r);
844 else if (r == DM_ENDIO_INCOMPLETE)
845 /* The target will handle the I/O */
847 else if (r == DM_ENDIO_REQUEUE)
848 /* The target wants to requeue the I/O */
849 dm_requeue_unmapped_request(clone);
851 DMWARN("unimplemented target endio return value: %d", r);
857 * Request completion handler for request-based dm
859 static void dm_softirq_done(struct request *rq)
862 struct request *clone = rq->completion_data;
863 struct dm_rq_target_io *tio = clone->end_io_data;
865 if (rq->cmd_flags & REQ_FAILED)
868 dm_done(clone, tio->error, mapped);
872 * Complete the clone and the original request with the error status
873 * through softirq context.
875 static void dm_complete_request(struct request *clone, int error)
877 struct dm_rq_target_io *tio = clone->end_io_data;
878 struct request *rq = tio->orig;
881 rq->completion_data = clone;
882 blk_complete_request(rq);
886 * Complete the not-mapped clone and the original request with the error status
887 * through softirq context.
888 * Target's rq_end_io() function isn't called.
889 * This may be used when the target's map_rq() function fails.
891 void dm_kill_unmapped_request(struct request *clone, int error)
893 struct dm_rq_target_io *tio = clone->end_io_data;
894 struct request *rq = tio->orig;
896 rq->cmd_flags |= REQ_FAILED;
897 dm_complete_request(clone, error);
899 EXPORT_SYMBOL_GPL(dm_kill_unmapped_request);
902 * Called with the queue lock held
904 static void end_clone_request(struct request *clone, int error)
907 * For just cleaning up the information of the queue in which
908 * the clone was dispatched.
909 * The clone is *NOT* freed actually here because it is alloced from
910 * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
912 __blk_put_request(clone->q, clone);
915 * Actual request completion is done in a softirq context which doesn't
916 * hold the queue lock. Otherwise, deadlock could occur because:
917 * - another request may be submitted by the upper level driver
918 * of the stacking during the completion
919 * - the submission which requires queue lock may be done
922 dm_complete_request(clone, error);
926 * Return maximum size of I/O possible at the supplied sector up to the current
929 static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
931 sector_t target_offset = dm_target_offset(ti, sector);
933 return ti->len - target_offset;
936 static sector_t max_io_len(sector_t sector, struct dm_target *ti)
938 sector_t len = max_io_len_target_boundary(sector, ti);
939 sector_t offset, max_len;
942 * Does the target need to split even further?
944 if (ti->max_io_len) {
945 offset = dm_target_offset(ti, sector);
946 if (unlikely(ti->max_io_len & (ti->max_io_len - 1)))
947 max_len = sector_div(offset, ti->max_io_len);
949 max_len = offset & (ti->max_io_len - 1);
950 max_len = ti->max_io_len - max_len;
959 int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
961 if (len > UINT_MAX) {
962 DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
963 (unsigned long long)len, UINT_MAX);
964 ti->error = "Maximum size of target IO is too large";
968 ti->max_io_len = (uint32_t) len;
972 EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
974 static void __map_bio(struct dm_target_io *tio)
978 struct mapped_device *md;
979 struct bio *clone = &tio->clone;
980 struct dm_target *ti = tio->ti;
982 clone->bi_end_io = clone_endio;
983 clone->bi_private = tio;
986 * Map the clone. If r == 0 we don't need to do
987 * anything, the target has assumed ownership of
990 atomic_inc(&tio->io->io_count);
991 sector = clone->bi_sector;
992 r = ti->type->map(ti, clone);
993 if (r == DM_MAPIO_REMAPPED) {
994 /* the bio has been remapped so dispatch it */
996 trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone,
997 tio->io->bio->bi_bdev->bd_dev, sector);
999 generic_make_request(clone);
1000 } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
1001 /* error the io and bail out, or requeue it if needed */
1003 dec_pending(tio->io, r);
1006 DMWARN("unimplemented target map return value: %d", r);
1012 struct mapped_device *md;
1013 struct dm_table *map;
1017 sector_t sector_count;
1021 static void bio_setup_sector(struct bio *bio, sector_t sector, sector_t len)
1023 bio->bi_sector = sector;
1024 bio->bi_size = to_bytes(len);
1027 static void bio_setup_bv(struct bio *bio, unsigned short idx, unsigned short bv_count)
1030 bio->bi_vcnt = idx + bv_count;
1031 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
1034 static void clone_bio_integrity(struct bio *bio, struct bio *clone,
1035 unsigned short idx, unsigned len, unsigned offset,
1038 if (!bio_integrity(bio))
1041 bio_integrity_clone(clone, bio, GFP_NOIO);
1044 bio_integrity_trim(clone, bio_sector_offset(bio, idx, offset), len);
1048 * Creates a little bio that just does part of a bvec.
1050 static void clone_split_bio(struct dm_target_io *tio, struct bio *bio,
1051 sector_t sector, unsigned short idx,
1052 unsigned offset, unsigned len)
1054 struct bio *clone = &tio->clone;
1055 struct bio_vec *bv = bio->bi_io_vec + idx;
1057 *clone->bi_io_vec = *bv;
1059 bio_setup_sector(clone, sector, len);
1061 clone->bi_bdev = bio->bi_bdev;
1062 clone->bi_rw = bio->bi_rw;
1064 clone->bi_io_vec->bv_offset = offset;
1065 clone->bi_io_vec->bv_len = clone->bi_size;
1066 clone->bi_flags |= 1 << BIO_CLONED;
1068 clone_bio_integrity(bio, clone, idx, len, offset, 1);
1072 * Creates a bio that consists of range of complete bvecs.
1074 static void clone_bio(struct dm_target_io *tio, struct bio *bio,
1075 sector_t sector, unsigned short idx,
1076 unsigned short bv_count, unsigned len)
1078 struct bio *clone = &tio->clone;
1081 __bio_clone(clone, bio);
1082 bio_setup_sector(clone, sector, len);
1083 bio_setup_bv(clone, idx, bv_count);
1085 if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
1087 clone_bio_integrity(bio, clone, idx, len, 0, trim);
1090 static struct dm_target_io *alloc_tio(struct clone_info *ci,
1091 struct dm_target *ti, int nr_iovecs,
1092 unsigned target_bio_nr)
1094 struct dm_target_io *tio;
1097 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, ci->md->bs);
1098 tio = container_of(clone, struct dm_target_io, clone);
1102 memset(&tio->info, 0, sizeof(tio->info));
1103 tio->target_bio_nr = target_bio_nr;
1108 static void __clone_and_map_simple_bio(struct clone_info *ci,
1109 struct dm_target *ti,
1110 unsigned target_bio_nr, sector_t len)
1112 struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs, target_bio_nr);
1113 struct bio *clone = &tio->clone;
1116 * Discard requests require the bio's inline iovecs be initialized.
1117 * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
1118 * and discard, so no need for concern about wasted bvec allocations.
1120 __bio_clone(clone, ci->bio);
1122 bio_setup_sector(clone, ci->sector, len);
1127 static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
1128 unsigned num_bios, sector_t len)
1130 unsigned target_bio_nr;
1132 for (target_bio_nr = 0; target_bio_nr < num_bios; target_bio_nr++)
1133 __clone_and_map_simple_bio(ci, ti, target_bio_nr, len);
1136 static int __send_empty_flush(struct clone_info *ci)
1138 unsigned target_nr = 0;
1139 struct dm_target *ti;
1141 BUG_ON(bio_has_data(ci->bio));
1142 while ((ti = dm_table_get_target(ci->map, target_nr++)))
1143 __send_duplicate_bios(ci, ti, ti->num_flush_bios, 0);
1148 static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
1149 sector_t sector, int nr_iovecs,
1150 unsigned short idx, unsigned short bv_count,
1151 unsigned offset, unsigned len,
1152 unsigned split_bvec)
1154 struct bio *bio = ci->bio;
1155 struct dm_target_io *tio;
1156 unsigned target_bio_nr;
1157 unsigned num_target_bios = 1;
1160 * Does the target want to receive duplicate copies of the bio?
1162 if (bio_data_dir(bio) == WRITE && ti->num_write_bios)
1163 num_target_bios = ti->num_write_bios(ti, bio);
1165 for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
1166 tio = alloc_tio(ci, ti, nr_iovecs, target_bio_nr);
1168 clone_split_bio(tio, bio, sector, idx, offset, len);
1170 clone_bio(tio, bio, sector, idx, bv_count, len);
1175 typedef unsigned (*get_num_bios_fn)(struct dm_target *ti);
1177 static unsigned get_num_discard_bios(struct dm_target *ti)
1179 return ti->num_discard_bios;
1182 static unsigned get_num_write_same_bios(struct dm_target *ti)
1184 return ti->num_write_same_bios;
1187 typedef bool (*is_split_required_fn)(struct dm_target *ti);
1189 static bool is_split_required_for_discard(struct dm_target *ti)
1191 return ti->split_discard_bios;
1194 static int __send_changing_extent_only(struct clone_info *ci,
1195 get_num_bios_fn get_num_bios,
1196 is_split_required_fn is_split_required)
1198 struct dm_target *ti;
1203 ti = dm_table_find_target(ci->map, ci->sector);
1204 if (!dm_target_is_valid(ti))
1208 * Even though the device advertised support for this type of
1209 * request, that does not mean every target supports it, and
1210 * reconfiguration might also have changed that since the
1211 * check was performed.
1213 num_bios = get_num_bios ? get_num_bios(ti) : 0;
1217 if (is_split_required && !is_split_required(ti))
1218 len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
1220 len = min(ci->sector_count, max_io_len(ci->sector, ti));
1222 __send_duplicate_bios(ci, ti, num_bios, len);
1225 } while (ci->sector_count -= len);
1230 static int __send_discard(struct clone_info *ci)
1232 return __send_changing_extent_only(ci, get_num_discard_bios,
1233 is_split_required_for_discard);
1236 static int __send_write_same(struct clone_info *ci)
1238 return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
1242 * Find maximum number of sectors / bvecs we can process with a single bio.
1244 static sector_t __len_within_target(struct clone_info *ci, sector_t max, int *idx)
1246 struct bio *bio = ci->bio;
1247 sector_t bv_len, total_len = 0;
1249 for (*idx = ci->idx; max && (*idx < bio->bi_vcnt); (*idx)++) {
1250 bv_len = to_sector(bio->bi_io_vec[*idx].bv_len);
1256 total_len += bv_len;
1262 static int __split_bvec_across_targets(struct clone_info *ci,
1263 struct dm_target *ti, sector_t max)
1265 struct bio *bio = ci->bio;
1266 struct bio_vec *bv = bio->bi_io_vec + ci->idx;
1267 sector_t remaining = to_sector(bv->bv_len);
1268 unsigned offset = 0;
1273 ti = dm_table_find_target(ci->map, ci->sector);
1274 if (!dm_target_is_valid(ti))
1277 max = max_io_len(ci->sector, ti);
1280 len = min(remaining, max);
1282 __clone_and_map_data_bio(ci, ti, ci->sector, 1, ci->idx, 0,
1283 bv->bv_offset + offset, len, 1);
1286 ci->sector_count -= len;
1287 offset += to_bytes(len);
1288 } while (remaining -= len);
1296 * Select the correct strategy for processing a non-flush bio.
1298 static int __split_and_process_non_flush(struct clone_info *ci)
1300 struct bio *bio = ci->bio;
1301 struct dm_target *ti;
1305 if (unlikely(bio->bi_rw & REQ_DISCARD))
1306 return __send_discard(ci);
1307 else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
1308 return __send_write_same(ci);
1310 ti = dm_table_find_target(ci->map, ci->sector);
1311 if (!dm_target_is_valid(ti))
1314 max = max_io_len(ci->sector, ti);
1317 * Optimise for the simple case where we can do all of
1318 * the remaining io with a single clone.
1320 if (ci->sector_count <= max) {
1321 __clone_and_map_data_bio(ci, ti, ci->sector, bio->bi_max_vecs,
1322 ci->idx, bio->bi_vcnt - ci->idx, 0,
1323 ci->sector_count, 0);
1324 ci->sector_count = 0;
1329 * There are some bvecs that don't span targets.
1330 * Do as many of these as possible.
1332 if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
1333 len = __len_within_target(ci, max, &idx);
1335 __clone_and_map_data_bio(ci, ti, ci->sector, bio->bi_max_vecs,
1336 ci->idx, idx - ci->idx, 0, len, 0);
1339 ci->sector_count -= len;
1346 * Handle a bvec that must be split between two or more targets.
1348 return __split_bvec_across_targets(ci, ti, max);
1352 * Entry point to split a bio into clones and submit them to the targets.
1354 static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
1356 struct clone_info ci;
1359 ci.map = dm_get_live_table(md);
1360 if (unlikely(!ci.map)) {
1366 ci.io = alloc_io(md);
1368 atomic_set(&ci.io->io_count, 1);
1371 spin_lock_init(&ci.io->endio_lock);
1372 ci.sector = bio->bi_sector;
1373 ci.idx = bio->bi_idx;
1375 start_io_acct(ci.io);
1377 if (bio->bi_rw & REQ_FLUSH) {
1378 ci.bio = &ci.md->flush_bio;
1379 ci.sector_count = 0;
1380 error = __send_empty_flush(&ci);
1381 /* dec_pending submits any data associated with flush */
1384 ci.sector_count = bio_sectors(bio);
1385 while (ci.sector_count && !error)
1386 error = __split_and_process_non_flush(&ci);
1389 /* drop the extra reference count */
1390 dec_pending(ci.io, error);
1391 dm_table_put(ci.map);
1393 /*-----------------------------------------------------------------
1395 *---------------------------------------------------------------*/
1397 static int dm_merge_bvec(struct request_queue *q,
1398 struct bvec_merge_data *bvm,
1399 struct bio_vec *biovec)
1401 struct mapped_device *md = q->queuedata;
1402 struct dm_table *map = dm_get_live_table(md);
1403 struct dm_target *ti;
1404 sector_t max_sectors;
1410 ti = dm_table_find_target(map, bvm->bi_sector);
1411 if (!dm_target_is_valid(ti))
1415 * Find maximum amount of I/O that won't need splitting
1417 max_sectors = min(max_io_len(bvm->bi_sector, ti),
1418 (sector_t) BIO_MAX_SECTORS);
1419 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
1424 * merge_bvec_fn() returns number of bytes
1425 * it can accept at this offset
1426 * max is precomputed maximal io size
1428 if (max_size && ti->type->merge)
1429 max_size = ti->type->merge(ti, bvm, biovec, max_size);
1431 * If the target doesn't support merge method and some of the devices
1432 * provided their merge_bvec method (we know this by looking at
1433 * queue_max_hw_sectors), then we can't allow bios with multiple vector
1434 * entries. So always set max_size to 0, and the code below allows
1437 else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
1446 * Always allow an entire first page
1448 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
1449 max_size = biovec->bv_len;
1455 * The request function that just remaps the bio built up by
1458 static void _dm_request(struct request_queue *q, struct bio *bio)
1460 int rw = bio_data_dir(bio);
1461 struct mapped_device *md = q->queuedata;
1464 down_read(&md->io_lock);
1466 cpu = part_stat_lock();
1467 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
1468 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
1471 /* if we're suspended, we have to queue this io for later */
1472 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
1473 up_read(&md->io_lock);
1475 if (bio_rw(bio) != READA)
1482 __split_and_process_bio(md, bio);
1483 up_read(&md->io_lock);
1487 static int dm_request_based(struct mapped_device *md)
1489 return blk_queue_stackable(md->queue);
1492 static void dm_request(struct request_queue *q, struct bio *bio)
1494 struct mapped_device *md = q->queuedata;
1496 if (dm_request_based(md))
1497 blk_queue_bio(q, bio);
1499 _dm_request(q, bio);
1502 void dm_dispatch_request(struct request *rq)
1506 if (blk_queue_io_stat(rq->q))
1507 rq->cmd_flags |= REQ_IO_STAT;
1509 rq->start_time = jiffies;
1510 r = blk_insert_cloned_request(rq->q, rq);
1512 dm_complete_request(rq, r);
1514 EXPORT_SYMBOL_GPL(dm_dispatch_request);
1516 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
1519 struct dm_rq_target_io *tio = data;
1520 struct dm_rq_clone_bio_info *info =
1521 container_of(bio, struct dm_rq_clone_bio_info, clone);
1523 info->orig = bio_orig;
1525 bio->bi_end_io = end_clone_bio;
1526 bio->bi_private = info;
1531 static int setup_clone(struct request *clone, struct request *rq,
1532 struct dm_rq_target_io *tio)
1536 r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
1537 dm_rq_bio_constructor, tio);
1541 clone->cmd = rq->cmd;
1542 clone->cmd_len = rq->cmd_len;
1543 clone->sense = rq->sense;
1544 clone->buffer = rq->buffer;
1545 clone->end_io = end_clone_request;
1546 clone->end_io_data = tio;
1551 static struct request *clone_rq(struct request *rq, struct mapped_device *md,
1554 struct request *clone;
1555 struct dm_rq_target_io *tio;
1557 tio = alloc_rq_tio(md, gfp_mask);
1565 memset(&tio->info, 0, sizeof(tio->info));
1567 clone = &tio->clone;
1568 if (setup_clone(clone, rq, tio)) {
1578 * Called with the queue lock held.
1580 static int dm_prep_fn(struct request_queue *q, struct request *rq)
1582 struct mapped_device *md = q->queuedata;
1583 struct request *clone;
1585 if (unlikely(rq->special)) {
1586 DMWARN("Already has something in rq->special.");
1587 return BLKPREP_KILL;
1590 clone = clone_rq(rq, md, GFP_ATOMIC);
1592 return BLKPREP_DEFER;
1594 rq->special = clone;
1595 rq->cmd_flags |= REQ_DONTPREP;
1602 * 0 : the request has been processed (not requeued)
1603 * !0 : the request has been requeued
1605 static int map_request(struct dm_target *ti, struct request *clone,
1606 struct mapped_device *md)
1608 int r, requeued = 0;
1609 struct dm_rq_target_io *tio = clone->end_io_data;
1612 r = ti->type->map_rq(ti, clone, &tio->info);
1614 case DM_MAPIO_SUBMITTED:
1615 /* The target has taken the I/O to submit by itself later */
1617 case DM_MAPIO_REMAPPED:
1618 /* The target has remapped the I/O so dispatch it */
1619 trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
1620 blk_rq_pos(tio->orig));
1621 dm_dispatch_request(clone);
1623 case DM_MAPIO_REQUEUE:
1624 /* The target wants to requeue the I/O */
1625 dm_requeue_unmapped_request(clone);
1630 DMWARN("unimplemented target map return value: %d", r);
1634 /* The target wants to complete the I/O */
1635 dm_kill_unmapped_request(clone, r);
1642 static struct request *dm_start_request(struct mapped_device *md, struct request *orig)
1644 struct request *clone;
1646 blk_start_request(orig);
1647 clone = orig->special;
1648 atomic_inc(&md->pending[rq_data_dir(clone)]);
1651 * Hold the md reference here for the in-flight I/O.
1652 * We can't rely on the reference count by device opener,
1653 * because the device may be closed during the request completion
1654 * when all bios are completed.
1655 * See the comment in rq_completed() too.
1663 * q->request_fn for request-based dm.
1664 * Called with the queue lock held.
1666 static void dm_request_fn(struct request_queue *q)
1668 struct mapped_device *md = q->queuedata;
1669 struct dm_table *map = dm_get_live_table(md);
1670 struct dm_target *ti;
1671 struct request *rq, *clone;
1675 * For suspend, check blk_queue_stopped() and increment
1676 * ->pending within a single queue_lock not to increment the
1677 * number of in-flight I/Os after the queue is stopped in
1680 while (!blk_queue_stopped(q)) {
1681 rq = blk_peek_request(q);
1685 /* always use block 0 to find the target for flushes for now */
1687 if (!(rq->cmd_flags & REQ_FLUSH))
1688 pos = blk_rq_pos(rq);
1690 ti = dm_table_find_target(map, pos);
1691 if (!dm_target_is_valid(ti)) {
1693 * Must perform setup, that dm_done() requires,
1694 * before calling dm_kill_unmapped_request
1696 DMERR_LIMIT("request attempted access beyond the end of device");
1697 clone = dm_start_request(md, rq);
1698 dm_kill_unmapped_request(clone, -EIO);
1702 if (ti->type->busy && ti->type->busy(ti))
1705 clone = dm_start_request(md, rq);
1707 spin_unlock(q->queue_lock);
1708 if (map_request(ti, clone, md))
1711 BUG_ON(!irqs_disabled());
1712 spin_lock(q->queue_lock);
1718 BUG_ON(!irqs_disabled());
1719 spin_lock(q->queue_lock);
1722 blk_delay_queue(q, HZ / 10);
1727 int dm_underlying_device_busy(struct request_queue *q)
1729 return blk_lld_busy(q);
1731 EXPORT_SYMBOL_GPL(dm_underlying_device_busy);
1733 static int dm_lld_busy(struct request_queue *q)
1736 struct mapped_device *md = q->queuedata;
1737 struct dm_table *map = dm_get_live_table(md);
1739 if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))
1742 r = dm_table_any_busy_target(map);
1749 static int dm_any_congested(void *congested_data, int bdi_bits)
1752 struct mapped_device *md = congested_data;
1753 struct dm_table *map;
1755 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
1756 map = dm_get_live_table(md);
1759 * Request-based dm cares about only own queue for
1760 * the query about congestion status of request_queue
1762 if (dm_request_based(md))
1763 r = md->queue->backing_dev_info.state &
1766 r = dm_table_any_congested(map, bdi_bits);
1775 /*-----------------------------------------------------------------
1776 * An IDR is used to keep track of allocated minor numbers.
1777 *---------------------------------------------------------------*/
1778 static void free_minor(int minor)
1780 spin_lock(&_minor_lock);
1781 idr_remove(&_minor_idr, minor);
1782 spin_unlock(&_minor_lock);
1786 * See if the device with a specific minor # is free.
1788 static int specific_minor(int minor)
1792 if (minor >= (1 << MINORBITS))
1795 idr_preload(GFP_KERNEL);
1796 spin_lock(&_minor_lock);
1798 r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
1800 spin_unlock(&_minor_lock);
1803 return r == -ENOSPC ? -EBUSY : r;
1807 static int next_free_minor(int *minor)
1811 idr_preload(GFP_KERNEL);
1812 spin_lock(&_minor_lock);
1814 r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
1816 spin_unlock(&_minor_lock);
1824 static const struct block_device_operations dm_blk_dops;
1826 static void dm_wq_work(struct work_struct *work);
1828 static void dm_init_md_queue(struct mapped_device *md)
1831 * Request-based dm devices cannot be stacked on top of bio-based dm
1832 * devices. The type of this dm device has not been decided yet.
1833 * The type is decided at the first table loading time.
1834 * To prevent problematic device stacking, clear the queue flag
1835 * for request stacking support until then.
1837 * This queue is new, so no concurrency on the queue_flags.
1839 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
1841 md->queue->queuedata = md;
1842 md->queue->backing_dev_info.congested_fn = dm_any_congested;
1843 md->queue->backing_dev_info.congested_data = md;
1844 blk_queue_make_request(md->queue, dm_request);
1845 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
1846 blk_queue_merge_bvec(md->queue, dm_merge_bvec);
1850 * Allocate and initialise a blank device with a given minor.
1852 static struct mapped_device *alloc_dev(int minor)
1855 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
1859 DMWARN("unable to allocate device, out of memory.");
1863 if (!try_module_get(THIS_MODULE))
1864 goto bad_module_get;
1866 /* get a minor number for the dev */
1867 if (minor == DM_ANY_MINOR)
1868 r = next_free_minor(&minor);
1870 r = specific_minor(minor);
1874 md->type = DM_TYPE_NONE;
1875 init_rwsem(&md->io_lock);
1876 mutex_init(&md->suspend_lock);
1877 mutex_init(&md->type_lock);
1878 spin_lock_init(&md->deferred_lock);
1879 rwlock_init(&md->map_lock);
1880 atomic_set(&md->holders, 1);
1881 atomic_set(&md->open_count, 0);
1882 atomic_set(&md->event_nr, 0);
1883 atomic_set(&md->uevent_seq, 0);
1884 INIT_LIST_HEAD(&md->uevent_list);
1885 spin_lock_init(&md->uevent_lock);
1887 md->queue = blk_alloc_queue(GFP_KERNEL);
1891 dm_init_md_queue(md);
1893 md->disk = alloc_disk(1);
1897 atomic_set(&md->pending[0], 0);
1898 atomic_set(&md->pending[1], 0);
1899 init_waitqueue_head(&md->wait);
1900 INIT_WORK(&md->work, dm_wq_work);
1901 init_waitqueue_head(&md->eventq);
1903 md->disk->major = _major;
1904 md->disk->first_minor = minor;
1905 md->disk->fops = &dm_blk_dops;
1906 md->disk->queue = md->queue;
1907 md->disk->private_data = md;
1908 sprintf(md->disk->disk_name, "dm-%d", minor);
1910 format_dev_t(md->name, MKDEV(_major, minor));
1912 md->wq = alloc_workqueue("kdmflush",
1913 WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
1917 md->bdev = bdget_disk(md->disk, 0);
1921 bio_init(&md->flush_bio);
1922 md->flush_bio.bi_bdev = md->bdev;
1923 md->flush_bio.bi_rw = WRITE_FLUSH;
1925 /* Populate the mapping, nobody knows we exist yet */
1926 spin_lock(&_minor_lock);
1927 old_md = idr_replace(&_minor_idr, md, minor);
1928 spin_unlock(&_minor_lock);
1930 BUG_ON(old_md != MINOR_ALLOCED);
1935 destroy_workqueue(md->wq);
1937 del_gendisk(md->disk);
1940 blk_cleanup_queue(md->queue);
1944 module_put(THIS_MODULE);
1950 static void unlock_fs(struct mapped_device *md);
1952 static void free_dev(struct mapped_device *md)
1954 int minor = MINOR(disk_devt(md->disk));
1958 destroy_workqueue(md->wq);
1960 mempool_destroy(md->io_pool);
1962 bioset_free(md->bs);
1963 blk_integrity_unregister(md->disk);
1964 del_gendisk(md->disk);
1967 spin_lock(&_minor_lock);
1968 md->disk->private_data = NULL;
1969 spin_unlock(&_minor_lock);
1972 blk_cleanup_queue(md->queue);
1973 module_put(THIS_MODULE);
1977 static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
1979 struct dm_md_mempools *p = dm_table_get_md_mempools(t);
1981 if (md->io_pool && md->bs) {
1982 /* The md already has necessary mempools. */
1983 if (dm_table_get_type(t) == DM_TYPE_BIO_BASED) {
1985 * Reload bioset because front_pad may have changed
1986 * because a different table was loaded.
1988 bioset_free(md->bs);
1991 } else if (dm_table_get_type(t) == DM_TYPE_REQUEST_BASED) {
1993 * There's no need to reload with request-based dm
1994 * because the size of front_pad doesn't change.
1995 * Note for future: If you are to reload bioset,
1996 * prep-ed requests in the queue may refer
1997 * to bio from the old bioset, so you must walk
1998 * through the queue to unprep.
2004 BUG_ON(!p || md->io_pool || md->bs);
2006 md->io_pool = p->io_pool;
2012 /* mempool bind completed, now no need any mempools in the table */
2013 dm_table_free_md_mempools(t);
2017 * Bind a table to the device.
2019 static void event_callback(void *context)
2021 unsigned long flags;
2023 struct mapped_device *md = (struct mapped_device *) context;
2025 spin_lock_irqsave(&md->uevent_lock, flags);
2026 list_splice_init(&md->uevent_list, &uevents);
2027 spin_unlock_irqrestore(&md->uevent_lock, flags);
2029 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
2031 atomic_inc(&md->event_nr);
2032 wake_up(&md->eventq);
2036 * Protected by md->suspend_lock obtained by dm_swap_table().
2038 static void __set_size(struct mapped_device *md, sector_t size)
2040 set_capacity(md->disk, size);
2042 i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
2046 * Return 1 if the queue has a compulsory merge_bvec_fn function.
2048 * If this function returns 0, then the device is either a non-dm
2049 * device without a merge_bvec_fn, or it is a dm device that is
2050 * able to split any bios it receives that are too big.
2052 int dm_queue_merge_is_compulsory(struct request_queue *q)
2054 struct mapped_device *dev_md;
2056 if (!q->merge_bvec_fn)
2059 if (q->make_request_fn == dm_request) {
2060 dev_md = q->queuedata;
2061 if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags))
2068 static int dm_device_merge_is_compulsory(struct dm_target *ti,
2069 struct dm_dev *dev, sector_t start,
2070 sector_t len, void *data)
2072 struct block_device *bdev = dev->bdev;
2073 struct request_queue *q = bdev_get_queue(bdev);
2075 return dm_queue_merge_is_compulsory(q);
2079 * Return 1 if it is acceptable to ignore merge_bvec_fn based
2080 * on the properties of the underlying devices.
2082 static int dm_table_merge_is_optional(struct dm_table *table)
2085 struct dm_target *ti;
2087 while (i < dm_table_get_num_targets(table)) {
2088 ti = dm_table_get_target(table, i++);
2090 if (ti->type->iterate_devices &&
2091 ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL))
2099 * Returns old map, which caller must destroy.
2101 static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
2102 struct queue_limits *limits)
2104 struct dm_table *old_map;
2105 struct request_queue *q = md->queue;
2107 unsigned long flags;
2108 int merge_is_optional;
2110 size = dm_table_get_size(t);
2113 * Wipe any geometry if the size of the table changed.
2115 if (size != get_capacity(md->disk))
2116 memset(&md->geometry, 0, sizeof(md->geometry));
2118 __set_size(md, size);
2120 dm_table_event_callback(t, event_callback, md);
2123 * The queue hasn't been stopped yet, if the old table type wasn't
2124 * for request-based during suspension. So stop it to prevent
2125 * I/O mapping before resume.
2126 * This must be done before setting the queue restrictions,
2127 * because request-based dm may be run just after the setting.
2129 if (dm_table_request_based(t) && !blk_queue_stopped(q))
2132 __bind_mempools(md, t);
2134 merge_is_optional = dm_table_merge_is_optional(t);
2136 write_lock_irqsave(&md->map_lock, flags);
2139 md->immutable_target_type = dm_table_get_immutable_target_type(t);
2141 dm_table_set_restrictions(t, q, limits);
2142 if (merge_is_optional)
2143 set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
2145 clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
2146 write_unlock_irqrestore(&md->map_lock, flags);
2152 * Returns unbound table for the caller to free.
2154 static struct dm_table *__unbind(struct mapped_device *md)
2156 struct dm_table *map = md->map;
2157 unsigned long flags;
2162 dm_table_event_callback(map, NULL, NULL);
2163 write_lock_irqsave(&md->map_lock, flags);
2165 write_unlock_irqrestore(&md->map_lock, flags);
2171 * Constructor for a new device.
2173 int dm_create(int minor, struct mapped_device **result)
2175 struct mapped_device *md;
2177 md = alloc_dev(minor);
2188 * Functions to manage md->type.
2189 * All are required to hold md->type_lock.
2191 void dm_lock_md_type(struct mapped_device *md)
2193 mutex_lock(&md->type_lock);
2196 void dm_unlock_md_type(struct mapped_device *md)
2198 mutex_unlock(&md->type_lock);
2201 void dm_set_md_type(struct mapped_device *md, unsigned type)
2206 unsigned dm_get_md_type(struct mapped_device *md)
2211 struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
2213 return md->immutable_target_type;
2217 * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
2219 static int dm_init_request_based_queue(struct mapped_device *md)
2221 struct request_queue *q = NULL;
2223 if (md->queue->elevator)
2226 /* Fully initialize the queue */
2227 q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL);
2232 dm_init_md_queue(md);
2233 blk_queue_softirq_done(md->queue, dm_softirq_done);
2234 blk_queue_prep_rq(md->queue, dm_prep_fn);
2235 blk_queue_lld_busy(md->queue, dm_lld_busy);
2237 elv_register_queue(md->queue);
2243 * Setup the DM device's queue based on md's type
2245 int dm_setup_md_queue(struct mapped_device *md)
2247 if ((dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) &&
2248 !dm_init_request_based_queue(md)) {
2249 DMWARN("Cannot initialize queue for request-based mapped device");
2256 static struct mapped_device *dm_find_md(dev_t dev)
2258 struct mapped_device *md;
2259 unsigned minor = MINOR(dev);
2261 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
2264 spin_lock(&_minor_lock);
2266 md = idr_find(&_minor_idr, minor);
2267 if (md && (md == MINOR_ALLOCED ||
2268 (MINOR(disk_devt(dm_disk(md))) != minor) ||
2269 dm_deleting_md(md) ||
2270 test_bit(DMF_FREEING, &md->flags))) {
2276 spin_unlock(&_minor_lock);
2281 struct mapped_device *dm_get_md(dev_t dev)
2283 struct mapped_device *md = dm_find_md(dev);
2290 EXPORT_SYMBOL_GPL(dm_get_md);
2292 void *dm_get_mdptr(struct mapped_device *md)
2294 return md->interface_ptr;
2297 void dm_set_mdptr(struct mapped_device *md, void *ptr)
2299 md->interface_ptr = ptr;
2302 void dm_get(struct mapped_device *md)
2304 atomic_inc(&md->holders);
2305 BUG_ON(test_bit(DMF_FREEING, &md->flags));
2308 const char *dm_device_name(struct mapped_device *md)
2312 EXPORT_SYMBOL_GPL(dm_device_name);
2314 static void __dm_destroy(struct mapped_device *md, bool wait)
2316 struct dm_table *map;
2320 spin_lock(&_minor_lock);
2321 map = dm_get_live_table(md);
2322 idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
2323 set_bit(DMF_FREEING, &md->flags);
2324 spin_unlock(&_minor_lock);
2326 if (!dm_suspended_md(md)) {
2327 dm_table_presuspend_targets(map);
2328 dm_table_postsuspend_targets(map);
2332 * Rare, but there may be I/O requests still going to complete,
2333 * for example. Wait for all references to disappear.
2334 * No one should increment the reference count of the mapped_device,
2335 * after the mapped_device state becomes DMF_FREEING.
2338 while (atomic_read(&md->holders))
2340 else if (atomic_read(&md->holders))
2341 DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
2342 dm_device_name(md), atomic_read(&md->holders));
2346 dm_table_destroy(__unbind(md));
2350 void dm_destroy(struct mapped_device *md)
2352 __dm_destroy(md, true);
2355 void dm_destroy_immediate(struct mapped_device *md)
2357 __dm_destroy(md, false);
2360 void dm_put(struct mapped_device *md)
2362 atomic_dec(&md->holders);
2364 EXPORT_SYMBOL_GPL(dm_put);
2366 static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
2369 DECLARE_WAITQUEUE(wait, current);
2371 add_wait_queue(&md->wait, &wait);
2374 set_current_state(interruptible);
2376 if (!md_in_flight(md))
2379 if (interruptible == TASK_INTERRUPTIBLE &&
2380 signal_pending(current)) {
2387 set_current_state(TASK_RUNNING);
2389 remove_wait_queue(&md->wait, &wait);
2395 * Process the deferred bios
2397 static void dm_wq_work(struct work_struct *work)
2399 struct mapped_device *md = container_of(work, struct mapped_device,
2403 down_read(&md->io_lock);
2405 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
2406 spin_lock_irq(&md->deferred_lock);
2407 c = bio_list_pop(&md->deferred);
2408 spin_unlock_irq(&md->deferred_lock);
2413 up_read(&md->io_lock);
2415 if (dm_request_based(md))
2416 generic_make_request(c);
2418 __split_and_process_bio(md, c);
2420 down_read(&md->io_lock);
2423 up_read(&md->io_lock);
2426 static void dm_queue_flush(struct mapped_device *md)
2428 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2429 smp_mb__after_clear_bit();
2430 queue_work(md->wq, &md->work);
2434 * Swap in a new table, returning the old one for the caller to destroy.
2436 struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
2438 struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
2439 struct queue_limits limits;
2442 mutex_lock(&md->suspend_lock);
2444 /* device must be suspended */
2445 if (!dm_suspended_md(md))
2449 * If the new table has no data devices, retain the existing limits.
2450 * This helps multipath with queue_if_no_path if all paths disappear,
2451 * then new I/O is queued based on these limits, and then some paths
2454 if (dm_table_has_no_data_devices(table)) {
2455 live_map = dm_get_live_table(md);
2457 limits = md->queue->limits;
2458 dm_table_put(live_map);
2462 r = dm_calculate_queue_limits(table, &limits);
2469 map = __bind(md, table, &limits);
2472 mutex_unlock(&md->suspend_lock);
2477 * Functions to lock and unlock any filesystem running on the
2480 static int lock_fs(struct mapped_device *md)
2484 WARN_ON(md->frozen_sb);
2486 md->frozen_sb = freeze_bdev(md->bdev);
2487 if (IS_ERR(md->frozen_sb)) {
2488 r = PTR_ERR(md->frozen_sb);
2489 md->frozen_sb = NULL;
2493 set_bit(DMF_FROZEN, &md->flags);
2498 static void unlock_fs(struct mapped_device *md)
2500 if (!test_bit(DMF_FROZEN, &md->flags))
2503 thaw_bdev(md->bdev, md->frozen_sb);
2504 md->frozen_sb = NULL;
2505 clear_bit(DMF_FROZEN, &md->flags);
2509 * We need to be able to change a mapping table under a mounted
2510 * filesystem. For example we might want to move some data in
2511 * the background. Before the table can be swapped with
2512 * dm_bind_table, dm_suspend must be called to flush any in
2513 * flight bios and ensure that any further io gets deferred.
2516 * Suspend mechanism in request-based dm.
2518 * 1. Flush all I/Os by lock_fs() if needed.
2519 * 2. Stop dispatching any I/O by stopping the request_queue.
2520 * 3. Wait for all in-flight I/Os to be completed or requeued.
2522 * To abort suspend, start the request_queue.
2524 int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
2526 struct dm_table *map = NULL;
2528 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
2529 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
2531 mutex_lock(&md->suspend_lock);
2533 if (dm_suspended_md(md)) {
2538 map = dm_get_live_table(md);
2541 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2542 * This flag is cleared before dm_suspend returns.
2545 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2547 /* This does not get reverted if there's an error later. */
2548 dm_table_presuspend_targets(map);
2551 * Flush I/O to the device.
2552 * Any I/O submitted after lock_fs() may not be flushed.
2553 * noflush takes precedence over do_lockfs.
2554 * (lock_fs() flushes I/Os and waits for them to complete.)
2556 if (!noflush && do_lockfs) {
2563 * Here we must make sure that no processes are submitting requests
2564 * to target drivers i.e. no one may be executing
2565 * __split_and_process_bio. This is called from dm_request and
2568 * To get all processes out of __split_and_process_bio in dm_request,
2569 * we take the write lock. To prevent any process from reentering
2570 * __split_and_process_bio from dm_request and quiesce the thread
2571 * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
2572 * flush_workqueue(md->wq).
2574 down_write(&md->io_lock);
2575 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2576 up_write(&md->io_lock);
2579 * Stop md->queue before flushing md->wq in case request-based
2580 * dm defers requests to md->wq from md->queue.
2582 if (dm_request_based(md))
2583 stop_queue(md->queue);
2585 flush_workqueue(md->wq);
2588 * At this point no more requests are entering target request routines.
2589 * We call dm_wait_for_completion to wait for all existing requests
2592 r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
2594 down_write(&md->io_lock);
2596 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2597 up_write(&md->io_lock);
2599 /* were we interrupted ? */
2603 if (dm_request_based(md))
2604 start_queue(md->queue);
2607 goto out; /* pushback list is already flushed, so skip flush */
2611 * If dm_wait_for_completion returned 0, the device is completely
2612 * quiescent now. There is no request-processing activity. All new
2613 * requests are being added to md->deferred list.
2616 set_bit(DMF_SUSPENDED, &md->flags);
2618 dm_table_postsuspend_targets(map);
2624 mutex_unlock(&md->suspend_lock);
2628 int dm_resume(struct mapped_device *md)
2631 struct dm_table *map = NULL;
2633 mutex_lock(&md->suspend_lock);
2634 if (!dm_suspended_md(md))
2637 map = dm_get_live_table(md);
2638 if (!map || !dm_table_get_size(map))
2641 r = dm_table_resume_targets(map);
2648 * Flushing deferred I/Os must be done after targets are resumed
2649 * so that mapping of targets can work correctly.
2650 * Request-based dm is queueing the deferred I/Os in its request_queue.
2652 if (dm_request_based(md))
2653 start_queue(md->queue);
2657 clear_bit(DMF_SUSPENDED, &md->flags);
2662 mutex_unlock(&md->suspend_lock);
2667 /*-----------------------------------------------------------------
2668 * Event notification.
2669 *---------------------------------------------------------------*/
2670 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
2673 char udev_cookie[DM_COOKIE_LENGTH];
2674 char *envp[] = { udev_cookie, NULL };
2677 return kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
2679 snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
2680 DM_COOKIE_ENV_VAR_NAME, cookie);
2681 return kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
2686 uint32_t dm_next_uevent_seq(struct mapped_device *md)
2688 return atomic_add_return(1, &md->uevent_seq);
2691 uint32_t dm_get_event_nr(struct mapped_device *md)
2693 return atomic_read(&md->event_nr);
2696 int dm_wait_event(struct mapped_device *md, int event_nr)
2698 return wait_event_interruptible(md->eventq,
2699 (event_nr != atomic_read(&md->event_nr)));
2702 void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
2704 unsigned long flags;
2706 spin_lock_irqsave(&md->uevent_lock, flags);
2707 list_add(elist, &md->uevent_list);
2708 spin_unlock_irqrestore(&md->uevent_lock, flags);
2712 * The gendisk is only valid as long as you have a reference
2715 struct gendisk *dm_disk(struct mapped_device *md)
2720 struct kobject *dm_kobject(struct mapped_device *md)
2726 * struct mapped_device should not be exported outside of dm.c
2727 * so use this check to verify that kobj is part of md structure
2729 struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
2731 struct mapped_device *md;
2733 md = container_of(kobj, struct mapped_device, kobj);
2734 if (&md->kobj != kobj)
2737 if (test_bit(DMF_FREEING, &md->flags) ||
2745 int dm_suspended_md(struct mapped_device *md)
2747 return test_bit(DMF_SUSPENDED, &md->flags);
2750 int dm_suspended(struct dm_target *ti)
2752 return dm_suspended_md(dm_table_get_md(ti->table));
2754 EXPORT_SYMBOL_GPL(dm_suspended);
2756 int dm_noflush_suspending(struct dm_target *ti)
2758 return __noflush_suspending(dm_table_get_md(ti->table));
2760 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
2762 struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size)
2764 struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL);
2765 struct kmem_cache *cachep;
2766 unsigned int pool_size;
2767 unsigned int front_pad;
2772 if (type == DM_TYPE_BIO_BASED) {
2775 front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
2776 } else if (type == DM_TYPE_REQUEST_BASED) {
2777 cachep = _rq_tio_cache;
2778 pool_size = MIN_IOS;
2779 front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
2780 /* per_bio_data_size is not used. See __bind_mempools(). */
2781 WARN_ON(per_bio_data_size != 0);
2785 pools->io_pool = mempool_create_slab_pool(MIN_IOS, cachep);
2786 if (!pools->io_pool)
2789 pools->bs = bioset_create(pool_size, front_pad);
2793 if (integrity && bioset_integrity_create(pools->bs, pool_size))
2799 dm_free_md_mempools(pools);
2804 void dm_free_md_mempools(struct dm_md_mempools *pools)
2810 mempool_destroy(pools->io_pool);
2813 bioset_free(pools->bs);
2818 static const struct block_device_operations dm_blk_dops = {
2819 .open = dm_blk_open,
2820 .release = dm_blk_close,
2821 .ioctl = dm_blk_ioctl,
2822 .getgeo = dm_blk_getgeo,
2823 .owner = THIS_MODULE
2826 EXPORT_SYMBOL(dm_get_mapinfo);
2831 module_init(dm_init);
2832 module_exit(dm_exit);
2834 module_param(major, uint, 0);
2835 MODULE_PARM_DESC(major, "The major number of the device mapper");
2836 MODULE_DESCRIPTION(DM_NAME " driver");
2837 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2838 MODULE_LICENSE("GPL");