2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5 * This file is released under the GPL.
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/mutex.h>
14 #include <linux/moduleparam.h>
15 #include <linux/blkpg.h>
16 #include <linux/bio.h>
17 #include <linux/buffer_head.h>
18 #include <linux/mempool.h>
19 #include <linux/slab.h>
20 #include <linux/idr.h>
21 #include <linux/hdreg.h>
23 #include <trace/events/block.h>
25 #define DM_MSG_PREFIX "core"
28 * Cookies are numeric values sent with CHANGE and REMOVE
29 * uevents while resuming, removing or renaming the device.
31 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
32 #define DM_COOKIE_LENGTH 24
34 static const char *_name = DM_NAME;
36 static unsigned int major = 0;
37 static unsigned int _major = 0;
39 static DEFINE_SPINLOCK(_minor_lock);
42 * One of these is allocated per bio.
45 struct mapped_device *md;
49 unsigned long start_time;
50 spinlock_t endio_lock;
55 * One of these is allocated per target within a bio. Hopefully
56 * this will be simplified out one day.
65 * For request-based dm.
66 * One of these is allocated per request.
68 struct dm_rq_target_io {
69 struct mapped_device *md;
71 struct request *orig, clone;
77 * For request-based dm.
78 * One of these is allocated per bio.
80 struct dm_rq_clone_bio_info {
82 struct dm_rq_target_io *tio;
85 union map_info *dm_get_mapinfo(struct bio *bio)
87 if (bio && bio->bi_private)
88 return &((struct dm_target_io *)bio->bi_private)->info;
92 union map_info *dm_get_rq_mapinfo(struct request *rq)
94 if (rq && rq->end_io_data)
95 return &((struct dm_rq_target_io *)rq->end_io_data)->info;
98 EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
100 #define MINOR_ALLOCED ((void *)-1)
103 * Bits for the md->flags field.
105 #define DMF_BLOCK_IO_FOR_SUSPEND 0
106 #define DMF_SUSPENDED 1
108 #define DMF_FREEING 3
109 #define DMF_DELETING 4
110 #define DMF_NOFLUSH_SUSPENDING 5
111 #define DMF_QUEUE_IO_TO_THREAD 6
114 * Work processed by per-device workqueue.
116 struct mapped_device {
117 struct rw_semaphore io_lock;
118 struct mutex suspend_lock;
125 struct request_queue *queue;
126 struct gendisk *disk;
132 * A list of ios that arrived while we were suspended.
135 wait_queue_head_t wait;
136 struct work_struct work;
137 struct bio_list deferred;
138 spinlock_t deferred_lock;
141 * An error from the barrier request currently being processed.
146 * Protect barrier_error from concurrent endio processing
147 * in request-based dm.
149 spinlock_t barrier_error_lock;
152 * Processing queue (flush/barriers)
154 struct workqueue_struct *wq;
155 struct work_struct barrier_work;
157 /* A pointer to the currently processing pre/post flush request */
158 struct request *flush_request;
161 * The current mapping.
163 struct dm_table *map;
166 * io objects are allocated from here.
177 wait_queue_head_t eventq;
179 struct list_head uevent_list;
180 spinlock_t uevent_lock; /* Protect access to uevent_list */
183 * freeze/thaw support require holding onto a super block
185 struct super_block *frozen_sb;
186 struct block_device *bdev;
188 /* forced geometry settings */
189 struct hd_geometry geometry;
191 /* For saving the address of __make_request for request based dm */
192 make_request_fn *saved_make_request_fn;
197 /* zero-length barrier that will be cloned and submitted to targets */
198 struct bio barrier_bio;
202 * For mempools pre-allocation at the table loading time.
204 struct dm_md_mempools {
211 static struct kmem_cache *_io_cache;
212 static struct kmem_cache *_tio_cache;
213 static struct kmem_cache *_rq_tio_cache;
214 static struct kmem_cache *_rq_bio_info_cache;
216 static int __init local_init(void)
220 /* allocate a slab for the dm_ios */
221 _io_cache = KMEM_CACHE(dm_io, 0);
225 /* allocate a slab for the target ios */
226 _tio_cache = KMEM_CACHE(dm_target_io, 0);
228 goto out_free_io_cache;
230 _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
232 goto out_free_tio_cache;
234 _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
235 if (!_rq_bio_info_cache)
236 goto out_free_rq_tio_cache;
238 r = dm_uevent_init();
240 goto out_free_rq_bio_info_cache;
243 r = register_blkdev(_major, _name);
245 goto out_uevent_exit;
254 out_free_rq_bio_info_cache:
255 kmem_cache_destroy(_rq_bio_info_cache);
256 out_free_rq_tio_cache:
257 kmem_cache_destroy(_rq_tio_cache);
259 kmem_cache_destroy(_tio_cache);
261 kmem_cache_destroy(_io_cache);
266 static void local_exit(void)
268 kmem_cache_destroy(_rq_bio_info_cache);
269 kmem_cache_destroy(_rq_tio_cache);
270 kmem_cache_destroy(_tio_cache);
271 kmem_cache_destroy(_io_cache);
272 unregister_blkdev(_major, _name);
277 DMINFO("cleaned up");
280 static int (*_inits[])(void) __initdata = {
290 static void (*_exits[])(void) = {
300 static int __init dm_init(void)
302 const int count = ARRAY_SIZE(_inits);
306 for (i = 0; i < count; i++) {
321 static void __exit dm_exit(void)
323 int i = ARRAY_SIZE(_exits);
330 * Block device functions
332 int dm_deleting_md(struct mapped_device *md)
334 return test_bit(DMF_DELETING, &md->flags);
337 static int dm_blk_open(struct block_device *bdev, fmode_t mode)
339 struct mapped_device *md;
341 spin_lock(&_minor_lock);
343 md = bdev->bd_disk->private_data;
347 if (test_bit(DMF_FREEING, &md->flags) ||
348 dm_deleting_md(md)) {
354 atomic_inc(&md->open_count);
357 spin_unlock(&_minor_lock);
359 return md ? 0 : -ENXIO;
362 static int dm_blk_close(struct gendisk *disk, fmode_t mode)
364 struct mapped_device *md = disk->private_data;
365 atomic_dec(&md->open_count);
370 int dm_open_count(struct mapped_device *md)
372 return atomic_read(&md->open_count);
376 * Guarantees nothing is using the device before it's deleted.
378 int dm_lock_for_deletion(struct mapped_device *md)
382 spin_lock(&_minor_lock);
384 if (dm_open_count(md))
387 set_bit(DMF_DELETING, &md->flags);
389 spin_unlock(&_minor_lock);
394 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
396 struct mapped_device *md = bdev->bd_disk->private_data;
398 return dm_get_geometry(md, geo);
401 static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
402 unsigned int cmd, unsigned long arg)
404 struct mapped_device *md = bdev->bd_disk->private_data;
405 struct dm_table *map = dm_get_live_table(md);
406 struct dm_target *tgt;
409 if (!map || !dm_table_get_size(map))
412 /* We only support devices that have a single target */
413 if (dm_table_get_num_targets(map) != 1)
416 tgt = dm_table_get_target(map, 0);
418 if (dm_suspended_md(md)) {
423 if (tgt->type->ioctl)
424 r = tgt->type->ioctl(tgt, cmd, arg);
432 static struct dm_io *alloc_io(struct mapped_device *md)
434 return mempool_alloc(md->io_pool, GFP_NOIO);
437 static void free_io(struct mapped_device *md, struct dm_io *io)
439 mempool_free(io, md->io_pool);
442 static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
444 mempool_free(tio, md->tio_pool);
447 static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
450 return mempool_alloc(md->tio_pool, gfp_mask);
453 static void free_rq_tio(struct dm_rq_target_io *tio)
455 mempool_free(tio, tio->md->tio_pool);
458 static struct dm_rq_clone_bio_info *alloc_bio_info(struct mapped_device *md)
460 return mempool_alloc(md->io_pool, GFP_ATOMIC);
463 static void free_bio_info(struct dm_rq_clone_bio_info *info)
465 mempool_free(info, info->tio->md->io_pool);
468 static int md_in_flight(struct mapped_device *md)
470 return atomic_read(&md->pending[READ]) +
471 atomic_read(&md->pending[WRITE]);
474 static void start_io_acct(struct dm_io *io)
476 struct mapped_device *md = io->md;
478 int rw = bio_data_dir(io->bio);
480 io->start_time = jiffies;
482 cpu = part_stat_lock();
483 part_round_stats(cpu, &dm_disk(md)->part0);
485 dm_disk(md)->part0.in_flight[rw] = atomic_inc_return(&md->pending[rw]);
488 static void end_io_acct(struct dm_io *io)
490 struct mapped_device *md = io->md;
491 struct bio *bio = io->bio;
492 unsigned long duration = jiffies - io->start_time;
494 int rw = bio_data_dir(bio);
496 cpu = part_stat_lock();
497 part_round_stats(cpu, &dm_disk(md)->part0);
498 part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
502 * After this is decremented the bio must not be touched if it is
505 dm_disk(md)->part0.in_flight[rw] = pending =
506 atomic_dec_return(&md->pending[rw]);
507 pending += atomic_read(&md->pending[rw^0x1]);
509 /* nudge anyone waiting on suspend queue */
515 * Add the bio to the list of deferred io.
517 static void queue_io(struct mapped_device *md, struct bio *bio)
519 down_write(&md->io_lock);
521 spin_lock_irq(&md->deferred_lock);
522 bio_list_add(&md->deferred, bio);
523 spin_unlock_irq(&md->deferred_lock);
525 if (!test_and_set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags))
526 queue_work(md->wq, &md->work);
528 up_write(&md->io_lock);
532 * Everyone (including functions in this file), should use this
533 * function to access the md->map field, and make sure they call
534 * dm_table_put() when finished.
536 struct dm_table *dm_get_live_table(struct mapped_device *md)
541 read_lock_irqsave(&md->map_lock, flags);
545 read_unlock_irqrestore(&md->map_lock, flags);
551 * Get the geometry associated with a dm device
553 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
561 * Set the geometry of a device.
563 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
565 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
567 if (geo->start > sz) {
568 DMWARN("Start sector is beyond the geometry limits.");
577 /*-----------------------------------------------------------------
579 * A more elegant soln is in the works that uses the queue
580 * merge fn, unfortunately there are a couple of changes to
581 * the block layer that I want to make for this. So in the
582 * interests of getting something for people to use I give
583 * you this clearly demarcated crap.
584 *---------------------------------------------------------------*/
586 static int __noflush_suspending(struct mapped_device *md)
588 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
592 * Decrements the number of outstanding ios that a bio has been
593 * cloned into, completing the original io if necc.
595 static void dec_pending(struct dm_io *io, int error)
600 struct mapped_device *md = io->md;
602 /* Push-back supersedes any I/O errors */
603 if (unlikely(error)) {
604 spin_lock_irqsave(&io->endio_lock, flags);
605 if (!(io->error > 0 && __noflush_suspending(md)))
607 spin_unlock_irqrestore(&io->endio_lock, flags);
610 if (atomic_dec_and_test(&io->io_count)) {
611 if (io->error == DM_ENDIO_REQUEUE) {
613 * Target requested pushing back the I/O.
615 spin_lock_irqsave(&md->deferred_lock, flags);
616 if (__noflush_suspending(md)) {
617 if (!bio_rw_flagged(io->bio, BIO_RW_BARRIER))
618 bio_list_add_head(&md->deferred,
621 /* noflush suspend was interrupted. */
623 spin_unlock_irqrestore(&md->deferred_lock, flags);
626 io_error = io->error;
629 if (bio_rw_flagged(bio, BIO_RW_BARRIER)) {
631 * There can be just one barrier request so we use
632 * a per-device variable for error reporting.
633 * Note that you can't touch the bio after end_io_acct
635 if (!md->barrier_error && io_error != -EOPNOTSUPP)
636 md->barrier_error = io_error;
641 if (io_error != DM_ENDIO_REQUEUE) {
642 trace_block_bio_complete(md->queue, bio);
644 bio_endio(bio, io_error);
652 static void clone_endio(struct bio *bio, int error)
655 struct dm_target_io *tio = bio->bi_private;
656 struct dm_io *io = tio->io;
657 struct mapped_device *md = tio->io->md;
658 dm_endio_fn endio = tio->ti->type->end_io;
660 if (!bio_flagged(bio, BIO_UPTODATE) && !error)
664 r = endio(tio->ti, bio, error, &tio->info);
665 if (r < 0 || r == DM_ENDIO_REQUEUE)
667 * error and requeue request are handled
671 else if (r == DM_ENDIO_INCOMPLETE)
672 /* The target will handle the io */
675 DMWARN("unimplemented target endio return value: %d", r);
681 * Store md for cleanup instead of tio which is about to get freed.
683 bio->bi_private = md->bs;
687 dec_pending(io, error);
691 * Partial completion handling for request-based dm
693 static void end_clone_bio(struct bio *clone, int error)
695 struct dm_rq_clone_bio_info *info = clone->bi_private;
696 struct dm_rq_target_io *tio = info->tio;
697 struct bio *bio = info->orig;
698 unsigned int nr_bytes = info->orig->bi_size;
704 * An error has already been detected on the request.
705 * Once error occurred, just let clone->end_io() handle
711 * Don't notice the error to the upper layer yet.
712 * The error handling decision is made by the target driver,
713 * when the request is completed.
720 * I/O for the bio successfully completed.
721 * Notice the data completion to the upper layer.
725 * bios are processed from the head of the list.
726 * So the completing bio should always be rq->bio.
727 * If it's not, something wrong is happening.
729 if (tio->orig->bio != bio)
730 DMERR("bio completion is going in the middle of the request");
733 * Update the original request.
734 * Do not use blk_end_request() here, because it may complete
735 * the original request before the clone, and break the ordering.
737 blk_update_request(tio->orig, 0, nr_bytes);
740 static void store_barrier_error(struct mapped_device *md, int error)
744 spin_lock_irqsave(&md->barrier_error_lock, flags);
746 * Basically, the first error is taken, but:
747 * -EOPNOTSUPP supersedes any I/O error.
748 * Requeue request supersedes any I/O error but -EOPNOTSUPP.
750 if (!md->barrier_error || error == -EOPNOTSUPP ||
751 (md->barrier_error != -EOPNOTSUPP &&
752 error == DM_ENDIO_REQUEUE))
753 md->barrier_error = error;
754 spin_unlock_irqrestore(&md->barrier_error_lock, flags);
758 * Don't touch any member of the md after calling this function because
759 * the md may be freed in dm_put() at the end of this function.
760 * Or do dm_get() before calling this function and dm_put() later.
762 static void rq_completed(struct mapped_device *md, int rw, int run_queue)
764 atomic_dec(&md->pending[rw]);
766 /* nudge anyone waiting on suspend queue */
767 if (!md_in_flight(md))
771 blk_run_queue(md->queue);
774 * dm_put() must be at the end of this function. See the comment above
779 static void free_rq_clone(struct request *clone)
781 struct dm_rq_target_io *tio = clone->end_io_data;
783 blk_rq_unprep_clone(clone);
788 * Complete the clone and the original request.
789 * Must be called without queue lock.
791 static void dm_end_request(struct request *clone, int error)
793 int rw = rq_data_dir(clone);
795 bool is_barrier = blk_barrier_rq(clone);
796 struct dm_rq_target_io *tio = clone->end_io_data;
797 struct mapped_device *md = tio->md;
798 struct request *rq = tio->orig;
800 if (blk_pc_request(rq) && !is_barrier) {
801 rq->errors = clone->errors;
802 rq->resid_len = clone->resid_len;
806 * We are using the sense buffer of the original
808 * So setting the length of the sense data is enough.
810 rq->sense_len = clone->sense_len;
813 free_rq_clone(clone);
815 if (unlikely(is_barrier)) {
817 store_barrier_error(md, error);
820 blk_end_request_all(rq, error);
822 rq_completed(md, rw, run_queue);
825 static void dm_unprep_request(struct request *rq)
827 struct request *clone = rq->special;
830 rq->cmd_flags &= ~REQ_DONTPREP;
832 free_rq_clone(clone);
836 * Requeue the original request of a clone.
838 void dm_requeue_unmapped_request(struct request *clone)
840 int rw = rq_data_dir(clone);
841 struct dm_rq_target_io *tio = clone->end_io_data;
842 struct mapped_device *md = tio->md;
843 struct request *rq = tio->orig;
844 struct request_queue *q = rq->q;
847 if (unlikely(blk_barrier_rq(clone))) {
849 * Barrier clones share an original request.
850 * Leave it to dm_end_request(), which handles this special
853 dm_end_request(clone, DM_ENDIO_REQUEUE);
857 dm_unprep_request(rq);
859 spin_lock_irqsave(q->queue_lock, flags);
860 if (elv_queue_empty(q))
862 blk_requeue_request(q, rq);
863 spin_unlock_irqrestore(q->queue_lock, flags);
865 rq_completed(md, rw, 0);
867 EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request);
869 static void __stop_queue(struct request_queue *q)
874 static void stop_queue(struct request_queue *q)
878 spin_lock_irqsave(q->queue_lock, flags);
880 spin_unlock_irqrestore(q->queue_lock, flags);
883 static void __start_queue(struct request_queue *q)
885 if (blk_queue_stopped(q))
889 static void start_queue(struct request_queue *q)
893 spin_lock_irqsave(q->queue_lock, flags);
895 spin_unlock_irqrestore(q->queue_lock, flags);
898 static void dm_done(struct request *clone, int error, bool mapped)
901 struct dm_rq_target_io *tio = clone->end_io_data;
902 dm_request_endio_fn rq_end_io = tio->ti->type->rq_end_io;
904 if (mapped && rq_end_io)
905 r = rq_end_io(tio->ti, clone, error, &tio->info);
908 /* The target wants to complete the I/O */
909 dm_end_request(clone, r);
910 else if (r == DM_ENDIO_INCOMPLETE)
911 /* The target will handle the I/O */
913 else if (r == DM_ENDIO_REQUEUE)
914 /* The target wants to requeue the I/O */
915 dm_requeue_unmapped_request(clone);
917 DMWARN("unimplemented target endio return value: %d", r);
923 * Request completion handler for request-based dm
925 static void dm_softirq_done(struct request *rq)
928 struct request *clone = rq->completion_data;
929 struct dm_rq_target_io *tio = clone->end_io_data;
931 if (rq->cmd_flags & REQ_FAILED)
934 dm_done(clone, tio->error, mapped);
938 * Complete the clone and the original request with the error status
939 * through softirq context.
941 static void dm_complete_request(struct request *clone, int error)
943 struct dm_rq_target_io *tio = clone->end_io_data;
944 struct request *rq = tio->orig;
946 if (unlikely(blk_barrier_rq(clone))) {
948 * Barrier clones share an original request. So can't use
949 * softirq_done with the original.
950 * Pass the clone to dm_done() directly in this special case.
951 * It is safe (even if clone->q->queue_lock is held here)
952 * because there is no I/O dispatching during the completion
955 dm_done(clone, error, true);
960 rq->completion_data = clone;
961 blk_complete_request(rq);
965 * Complete the not-mapped clone and the original request with the error status
966 * through softirq context.
967 * Target's rq_end_io() function isn't called.
968 * This may be used when the target's map_rq() function fails.
970 void dm_kill_unmapped_request(struct request *clone, int error)
972 struct dm_rq_target_io *tio = clone->end_io_data;
973 struct request *rq = tio->orig;
975 if (unlikely(blk_barrier_rq(clone))) {
977 * Barrier clones share an original request.
978 * Leave it to dm_end_request(), which handles this special
982 dm_end_request(clone, error);
986 rq->cmd_flags |= REQ_FAILED;
987 dm_complete_request(clone, error);
989 EXPORT_SYMBOL_GPL(dm_kill_unmapped_request);
992 * Called with the queue lock held
994 static void end_clone_request(struct request *clone, int error)
997 * For just cleaning up the information of the queue in which
998 * the clone was dispatched.
999 * The clone is *NOT* freed actually here because it is alloced from
1000 * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
1002 __blk_put_request(clone->q, clone);
1005 * Actual request completion is done in a softirq context which doesn't
1006 * hold the queue lock. Otherwise, deadlock could occur because:
1007 * - another request may be submitted by the upper level driver
1008 * of the stacking during the completion
1009 * - the submission which requires queue lock may be done
1010 * against this queue
1012 dm_complete_request(clone, error);
1015 static sector_t max_io_len(struct mapped_device *md,
1016 sector_t sector, struct dm_target *ti)
1018 sector_t offset = sector - ti->begin;
1019 sector_t len = ti->len - offset;
1022 * Does the target need to split even further ?
1026 boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
1035 static void __map_bio(struct dm_target *ti, struct bio *clone,
1036 struct dm_target_io *tio)
1040 struct mapped_device *md;
1042 clone->bi_end_io = clone_endio;
1043 clone->bi_private = tio;
1046 * Map the clone. If r == 0 we don't need to do
1047 * anything, the target has assumed ownership of
1050 atomic_inc(&tio->io->io_count);
1051 sector = clone->bi_sector;
1052 r = ti->type->map(ti, clone, &tio->info);
1053 if (r == DM_MAPIO_REMAPPED) {
1054 /* the bio has been remapped so dispatch it */
1056 trace_block_remap(bdev_get_queue(clone->bi_bdev), clone,
1057 tio->io->bio->bi_bdev->bd_dev, sector);
1059 generic_make_request(clone);
1060 } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
1061 /* error the io and bail out, or requeue it if needed */
1063 dec_pending(tio->io, r);
1065 * Store bio_set for cleanup.
1067 clone->bi_private = md->bs;
1071 DMWARN("unimplemented target map return value: %d", r);
1077 struct mapped_device *md;
1078 struct dm_table *map;
1082 sector_t sector_count;
1086 static void dm_bio_destructor(struct bio *bio)
1088 struct bio_set *bs = bio->bi_private;
1094 * Creates a little bio that is just does part of a bvec.
1096 static struct bio *split_bvec(struct bio *bio, sector_t sector,
1097 unsigned short idx, unsigned int offset,
1098 unsigned int len, struct bio_set *bs)
1101 struct bio_vec *bv = bio->bi_io_vec + idx;
1103 clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
1104 clone->bi_destructor = dm_bio_destructor;
1105 *clone->bi_io_vec = *bv;
1107 clone->bi_sector = sector;
1108 clone->bi_bdev = bio->bi_bdev;
1109 clone->bi_rw = bio->bi_rw & ~(1 << BIO_RW_BARRIER);
1111 clone->bi_size = to_bytes(len);
1112 clone->bi_io_vec->bv_offset = offset;
1113 clone->bi_io_vec->bv_len = clone->bi_size;
1114 clone->bi_flags |= 1 << BIO_CLONED;
1116 if (bio_integrity(bio)) {
1117 bio_integrity_clone(clone, bio, GFP_NOIO, bs);
1118 bio_integrity_trim(clone,
1119 bio_sector_offset(bio, idx, offset), len);
1126 * Creates a bio that consists of range of complete bvecs.
1128 static struct bio *clone_bio(struct bio *bio, sector_t sector,
1129 unsigned short idx, unsigned short bv_count,
1130 unsigned int len, struct bio_set *bs)
1134 clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
1135 __bio_clone(clone, bio);
1136 clone->bi_rw &= ~(1 << BIO_RW_BARRIER);
1137 clone->bi_destructor = dm_bio_destructor;
1138 clone->bi_sector = sector;
1139 clone->bi_idx = idx;
1140 clone->bi_vcnt = idx + bv_count;
1141 clone->bi_size = to_bytes(len);
1142 clone->bi_flags &= ~(1 << BIO_SEG_VALID);
1144 if (bio_integrity(bio)) {
1145 bio_integrity_clone(clone, bio, GFP_NOIO, bs);
1147 if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
1148 bio_integrity_trim(clone,
1149 bio_sector_offset(bio, idx, 0), len);
1155 static struct dm_target_io *alloc_tio(struct clone_info *ci,
1156 struct dm_target *ti)
1158 struct dm_target_io *tio = mempool_alloc(ci->md->tio_pool, GFP_NOIO);
1162 memset(&tio->info, 0, sizeof(tio->info));
1167 static void __flush_target(struct clone_info *ci, struct dm_target *ti,
1170 struct dm_target_io *tio = alloc_tio(ci, ti);
1173 tio->info.flush_request = flush_nr;
1175 clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs);
1176 __bio_clone(clone, ci->bio);
1177 clone->bi_destructor = dm_bio_destructor;
1179 __map_bio(ti, clone, tio);
1182 static int __clone_and_map_empty_barrier(struct clone_info *ci)
1184 unsigned target_nr = 0, flush_nr;
1185 struct dm_target *ti;
1187 while ((ti = dm_table_get_target(ci->map, target_nr++)))
1188 for (flush_nr = 0; flush_nr < ti->num_flush_requests;
1190 __flush_target(ci, ti, flush_nr);
1192 ci->sector_count = 0;
1197 static int __clone_and_map(struct clone_info *ci)
1199 struct bio *clone, *bio = ci->bio;
1200 struct dm_target *ti;
1201 sector_t len = 0, max;
1202 struct dm_target_io *tio;
1204 if (unlikely(bio_empty_barrier(bio)))
1205 return __clone_and_map_empty_barrier(ci);
1207 ti = dm_table_find_target(ci->map, ci->sector);
1208 if (!dm_target_is_valid(ti))
1211 max = max_io_len(ci->md, ci->sector, ti);
1214 * Allocate a target io object.
1216 tio = alloc_tio(ci, ti);
1218 if (ci->sector_count <= max) {
1220 * Optimise for the simple case where we can do all of
1221 * the remaining io with a single clone.
1223 clone = clone_bio(bio, ci->sector, ci->idx,
1224 bio->bi_vcnt - ci->idx, ci->sector_count,
1226 __map_bio(ti, clone, tio);
1227 ci->sector_count = 0;
1229 } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
1231 * There are some bvecs that don't span targets.
1232 * Do as many of these as possible.
1235 sector_t remaining = max;
1238 for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
1239 bv_len = to_sector(bio->bi_io_vec[i].bv_len);
1241 if (bv_len > remaining)
1244 remaining -= bv_len;
1248 clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len,
1250 __map_bio(ti, clone, tio);
1253 ci->sector_count -= len;
1258 * Handle a bvec that must be split between two or more targets.
1260 struct bio_vec *bv = bio->bi_io_vec + ci->idx;
1261 sector_t remaining = to_sector(bv->bv_len);
1262 unsigned int offset = 0;
1266 ti = dm_table_find_target(ci->map, ci->sector);
1267 if (!dm_target_is_valid(ti))
1270 max = max_io_len(ci->md, ci->sector, ti);
1272 tio = alloc_tio(ci, ti);
1275 len = min(remaining, max);
1277 clone = split_bvec(bio, ci->sector, ci->idx,
1278 bv->bv_offset + offset, len,
1281 __map_bio(ti, clone, tio);
1284 ci->sector_count -= len;
1285 offset += to_bytes(len);
1286 } while (remaining -= len);
1295 * Split the bio into several clones and submit it to targets.
1297 static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
1299 struct clone_info ci;
1302 ci.map = dm_get_live_table(md);
1303 if (unlikely(!ci.map)) {
1304 if (!bio_rw_flagged(bio, BIO_RW_BARRIER))
1307 if (!md->barrier_error)
1308 md->barrier_error = -EIO;
1314 ci.io = alloc_io(md);
1316 atomic_set(&ci.io->io_count, 1);
1319 spin_lock_init(&ci.io->endio_lock);
1320 ci.sector = bio->bi_sector;
1321 ci.sector_count = bio_sectors(bio);
1322 if (unlikely(bio_empty_barrier(bio)))
1323 ci.sector_count = 1;
1324 ci.idx = bio->bi_idx;
1326 start_io_acct(ci.io);
1327 while (ci.sector_count && !error)
1328 error = __clone_and_map(&ci);
1330 /* drop the extra reference count */
1331 dec_pending(ci.io, error);
1332 dm_table_put(ci.map);
1334 /*-----------------------------------------------------------------
1336 *---------------------------------------------------------------*/
1338 static int dm_merge_bvec(struct request_queue *q,
1339 struct bvec_merge_data *bvm,
1340 struct bio_vec *biovec)
1342 struct mapped_device *md = q->queuedata;
1343 struct dm_table *map = dm_get_live_table(md);
1344 struct dm_target *ti;
1345 sector_t max_sectors;
1351 ti = dm_table_find_target(map, bvm->bi_sector);
1352 if (!dm_target_is_valid(ti))
1356 * Find maximum amount of I/O that won't need splitting
1358 max_sectors = min(max_io_len(md, bvm->bi_sector, ti),
1359 (sector_t) BIO_MAX_SECTORS);
1360 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
1365 * merge_bvec_fn() returns number of bytes
1366 * it can accept at this offset
1367 * max is precomputed maximal io size
1369 if (max_size && ti->type->merge)
1370 max_size = ti->type->merge(ti, bvm, biovec, max_size);
1372 * If the target doesn't support merge method and some of the devices
1373 * provided their merge_bvec method (we know this by looking at
1374 * queue_max_hw_sectors), then we can't allow bios with multiple vector
1375 * entries. So always set max_size to 0, and the code below allows
1378 else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
1387 * Always allow an entire first page
1389 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
1390 max_size = biovec->bv_len;
1396 * The request function that just remaps the bio built up by
1399 static int _dm_request(struct request_queue *q, struct bio *bio)
1401 int rw = bio_data_dir(bio);
1402 struct mapped_device *md = q->queuedata;
1405 down_read(&md->io_lock);
1407 cpu = part_stat_lock();
1408 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
1409 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
1413 * If we're suspended or the thread is processing barriers
1414 * we have to queue this io for later.
1416 if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) ||
1417 unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
1418 up_read(&md->io_lock);
1420 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) &&
1421 bio_rw(bio) == READA) {
1431 __split_and_process_bio(md, bio);
1432 up_read(&md->io_lock);
1436 static int dm_make_request(struct request_queue *q, struct bio *bio)
1438 struct mapped_device *md = q->queuedata;
1440 return md->saved_make_request_fn(q, bio); /* call __make_request() */
1443 static int dm_request_based(struct mapped_device *md)
1445 return blk_queue_stackable(md->queue);
1448 static int dm_request(struct request_queue *q, struct bio *bio)
1450 struct mapped_device *md = q->queuedata;
1452 if (dm_request_based(md))
1453 return dm_make_request(q, bio);
1455 return _dm_request(q, bio);
1459 * Mark this request as flush request, so that dm_request_fn() can
1462 static void dm_rq_prepare_flush(struct request_queue *q, struct request *rq)
1464 rq->cmd_type = REQ_TYPE_LINUX_BLOCK;
1465 rq->cmd[0] = REQ_LB_OP_FLUSH;
1468 static bool dm_rq_is_flush_request(struct request *rq)
1470 if (rq->cmd_type == REQ_TYPE_LINUX_BLOCK &&
1471 rq->cmd[0] == REQ_LB_OP_FLUSH)
1477 void dm_dispatch_request(struct request *rq)
1481 if (blk_queue_io_stat(rq->q))
1482 rq->cmd_flags |= REQ_IO_STAT;
1484 rq->start_time = jiffies;
1485 r = blk_insert_cloned_request(rq->q, rq);
1487 dm_complete_request(rq, r);
1489 EXPORT_SYMBOL_GPL(dm_dispatch_request);
1491 static void dm_rq_bio_destructor(struct bio *bio)
1493 struct dm_rq_clone_bio_info *info = bio->bi_private;
1494 struct mapped_device *md = info->tio->md;
1496 free_bio_info(info);
1497 bio_free(bio, md->bs);
1500 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
1503 struct dm_rq_target_io *tio = data;
1504 struct mapped_device *md = tio->md;
1505 struct dm_rq_clone_bio_info *info = alloc_bio_info(md);
1510 info->orig = bio_orig;
1512 bio->bi_end_io = end_clone_bio;
1513 bio->bi_private = info;
1514 bio->bi_destructor = dm_rq_bio_destructor;
1519 static int setup_clone(struct request *clone, struct request *rq,
1520 struct dm_rq_target_io *tio)
1524 if (dm_rq_is_flush_request(rq)) {
1525 blk_rq_init(NULL, clone);
1526 clone->cmd_type = REQ_TYPE_FS;
1527 clone->cmd_flags |= (REQ_HARDBARRIER | WRITE);
1529 r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
1530 dm_rq_bio_constructor, tio);
1534 clone->cmd = rq->cmd;
1535 clone->cmd_len = rq->cmd_len;
1536 clone->sense = rq->sense;
1537 clone->buffer = rq->buffer;
1540 clone->end_io = end_clone_request;
1541 clone->end_io_data = tio;
1546 static struct request *clone_rq(struct request *rq, struct mapped_device *md,
1549 struct request *clone;
1550 struct dm_rq_target_io *tio;
1552 tio = alloc_rq_tio(md, gfp_mask);
1560 memset(&tio->info, 0, sizeof(tio->info));
1562 clone = &tio->clone;
1563 if (setup_clone(clone, rq, tio)) {
1573 * Called with the queue lock held.
1575 static int dm_prep_fn(struct request_queue *q, struct request *rq)
1577 struct mapped_device *md = q->queuedata;
1578 struct request *clone;
1580 if (unlikely(dm_rq_is_flush_request(rq)))
1583 if (unlikely(rq->special)) {
1584 DMWARN("Already has something in rq->special.");
1585 return BLKPREP_KILL;
1588 clone = clone_rq(rq, md, GFP_ATOMIC);
1590 return BLKPREP_DEFER;
1592 rq->special = clone;
1593 rq->cmd_flags |= REQ_DONTPREP;
1598 static void map_request(struct dm_target *ti, struct request *clone,
1599 struct mapped_device *md)
1602 struct dm_rq_target_io *tio = clone->end_io_data;
1605 * Hold the md reference here for the in-flight I/O.
1606 * We can't rely on the reference count by device opener,
1607 * because the device may be closed during the request completion
1608 * when all bios are completed.
1609 * See the comment in rq_completed() too.
1614 r = ti->type->map_rq(ti, clone, &tio->info);
1616 case DM_MAPIO_SUBMITTED:
1617 /* The target has taken the I/O to submit by itself later */
1619 case DM_MAPIO_REMAPPED:
1620 /* The target has remapped the I/O so dispatch it */
1621 trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
1622 blk_rq_pos(tio->orig));
1623 dm_dispatch_request(clone);
1625 case DM_MAPIO_REQUEUE:
1626 /* The target wants to requeue the I/O */
1627 dm_requeue_unmapped_request(clone);
1631 DMWARN("unimplemented target map return value: %d", r);
1635 /* The target wants to complete the I/O */
1636 dm_kill_unmapped_request(clone, r);
1642 * q->request_fn for request-based dm.
1643 * Called with the queue lock held.
1645 static void dm_request_fn(struct request_queue *q)
1647 struct mapped_device *md = q->queuedata;
1648 struct dm_table *map = dm_get_live_table(md);
1649 struct dm_target *ti;
1650 struct request *rq, *clone;
1653 * For suspend, check blk_queue_stopped() and increment
1654 * ->pending within a single queue_lock not to increment the
1655 * number of in-flight I/Os after the queue is stopped in
1658 while (!blk_queue_plugged(q) && !blk_queue_stopped(q)) {
1659 rq = blk_peek_request(q);
1663 if (unlikely(dm_rq_is_flush_request(rq))) {
1664 BUG_ON(md->flush_request);
1665 md->flush_request = rq;
1666 blk_start_request(rq);
1667 queue_work(md->wq, &md->barrier_work);
1671 ti = dm_table_find_target(map, blk_rq_pos(rq));
1672 if (ti->type->busy && ti->type->busy(ti))
1675 blk_start_request(rq);
1676 clone = rq->special;
1677 atomic_inc(&md->pending[rq_data_dir(clone)]);
1679 spin_unlock(q->queue_lock);
1680 map_request(ti, clone, md);
1681 spin_lock_irq(q->queue_lock);
1687 if (!elv_queue_empty(q))
1688 /* Some requests still remain, retry later */
1697 int dm_underlying_device_busy(struct request_queue *q)
1699 return blk_lld_busy(q);
1701 EXPORT_SYMBOL_GPL(dm_underlying_device_busy);
1703 static int dm_lld_busy(struct request_queue *q)
1706 struct mapped_device *md = q->queuedata;
1707 struct dm_table *map = dm_get_live_table(md);
1709 if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))
1712 r = dm_table_any_busy_target(map);
1719 static void dm_unplug_all(struct request_queue *q)
1721 struct mapped_device *md = q->queuedata;
1722 struct dm_table *map = dm_get_live_table(md);
1725 if (dm_request_based(md))
1726 generic_unplug_device(q);
1728 dm_table_unplug_all(map);
1733 static int dm_any_congested(void *congested_data, int bdi_bits)
1736 struct mapped_device *md = congested_data;
1737 struct dm_table *map;
1739 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
1740 map = dm_get_live_table(md);
1743 * Request-based dm cares about only own queue for
1744 * the query about congestion status of request_queue
1746 if (dm_request_based(md))
1747 r = md->queue->backing_dev_info.state &
1750 r = dm_table_any_congested(map, bdi_bits);
1759 /*-----------------------------------------------------------------
1760 * An IDR is used to keep track of allocated minor numbers.
1761 *---------------------------------------------------------------*/
1762 static DEFINE_IDR(_minor_idr);
1764 static void free_minor(int minor)
1766 spin_lock(&_minor_lock);
1767 idr_remove(&_minor_idr, minor);
1768 spin_unlock(&_minor_lock);
1772 * See if the device with a specific minor # is free.
1774 static int specific_minor(int minor)
1778 if (minor >= (1 << MINORBITS))
1781 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1785 spin_lock(&_minor_lock);
1787 if (idr_find(&_minor_idr, minor)) {
1792 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
1797 idr_remove(&_minor_idr, m);
1803 spin_unlock(&_minor_lock);
1807 static int next_free_minor(int *minor)
1811 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1815 spin_lock(&_minor_lock);
1817 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
1821 if (m >= (1 << MINORBITS)) {
1822 idr_remove(&_minor_idr, m);
1830 spin_unlock(&_minor_lock);
1834 static const struct block_device_operations dm_blk_dops;
1836 static void dm_wq_work(struct work_struct *work);
1837 static void dm_rq_barrier_work(struct work_struct *work);
1840 * Allocate and initialise a blank device with a given minor.
1842 static struct mapped_device *alloc_dev(int minor)
1845 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
1849 DMWARN("unable to allocate device, out of memory.");
1853 if (!try_module_get(THIS_MODULE))
1854 goto bad_module_get;
1856 /* get a minor number for the dev */
1857 if (minor == DM_ANY_MINOR)
1858 r = next_free_minor(&minor);
1860 r = specific_minor(minor);
1864 init_rwsem(&md->io_lock);
1865 mutex_init(&md->suspend_lock);
1866 spin_lock_init(&md->deferred_lock);
1867 spin_lock_init(&md->barrier_error_lock);
1868 rwlock_init(&md->map_lock);
1869 atomic_set(&md->holders, 1);
1870 atomic_set(&md->open_count, 0);
1871 atomic_set(&md->event_nr, 0);
1872 atomic_set(&md->uevent_seq, 0);
1873 INIT_LIST_HEAD(&md->uevent_list);
1874 spin_lock_init(&md->uevent_lock);
1876 md->queue = blk_init_queue(dm_request_fn, NULL);
1881 * Request-based dm devices cannot be stacked on top of bio-based dm
1882 * devices. The type of this dm device has not been decided yet,
1883 * although we initialized the queue using blk_init_queue().
1884 * The type is decided at the first table loading time.
1885 * To prevent problematic device stacking, clear the queue flag
1886 * for request stacking support until then.
1888 * This queue is new, so no concurrency on the queue_flags.
1890 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
1891 md->saved_make_request_fn = md->queue->make_request_fn;
1892 md->queue->queuedata = md;
1893 md->queue->backing_dev_info.congested_fn = dm_any_congested;
1894 md->queue->backing_dev_info.congested_data = md;
1895 blk_queue_make_request(md->queue, dm_request);
1896 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
1897 md->queue->unplug_fn = dm_unplug_all;
1898 blk_queue_merge_bvec(md->queue, dm_merge_bvec);
1899 blk_queue_softirq_done(md->queue, dm_softirq_done);
1900 blk_queue_prep_rq(md->queue, dm_prep_fn);
1901 blk_queue_lld_busy(md->queue, dm_lld_busy);
1902 blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN_FLUSH,
1903 dm_rq_prepare_flush);
1905 md->disk = alloc_disk(1);
1909 atomic_set(&md->pending[0], 0);
1910 atomic_set(&md->pending[1], 0);
1911 init_waitqueue_head(&md->wait);
1912 INIT_WORK(&md->work, dm_wq_work);
1913 INIT_WORK(&md->barrier_work, dm_rq_barrier_work);
1914 init_waitqueue_head(&md->eventq);
1916 md->disk->major = _major;
1917 md->disk->first_minor = minor;
1918 md->disk->fops = &dm_blk_dops;
1919 md->disk->queue = md->queue;
1920 md->disk->private_data = md;
1921 sprintf(md->disk->disk_name, "dm-%d", minor);
1923 format_dev_t(md->name, MKDEV(_major, minor));
1925 md->wq = create_singlethread_workqueue("kdmflush");
1929 md->bdev = bdget_disk(md->disk, 0);
1933 /* Populate the mapping, nobody knows we exist yet */
1934 spin_lock(&_minor_lock);
1935 old_md = idr_replace(&_minor_idr, md, minor);
1936 spin_unlock(&_minor_lock);
1938 BUG_ON(old_md != MINOR_ALLOCED);
1943 destroy_workqueue(md->wq);
1945 del_gendisk(md->disk);
1948 blk_cleanup_queue(md->queue);
1952 module_put(THIS_MODULE);
1958 static void unlock_fs(struct mapped_device *md);
1960 static void free_dev(struct mapped_device *md)
1962 int minor = MINOR(disk_devt(md->disk));
1966 destroy_workqueue(md->wq);
1968 mempool_destroy(md->tio_pool);
1970 mempool_destroy(md->io_pool);
1972 bioset_free(md->bs);
1973 blk_integrity_unregister(md->disk);
1974 del_gendisk(md->disk);
1977 spin_lock(&_minor_lock);
1978 md->disk->private_data = NULL;
1979 spin_unlock(&_minor_lock);
1982 blk_cleanup_queue(md->queue);
1983 module_put(THIS_MODULE);
1987 static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
1989 struct dm_md_mempools *p;
1991 if (md->io_pool && md->tio_pool && md->bs)
1992 /* the md already has necessary mempools */
1995 p = dm_table_get_md_mempools(t);
1996 BUG_ON(!p || md->io_pool || md->tio_pool || md->bs);
1998 md->io_pool = p->io_pool;
2000 md->tio_pool = p->tio_pool;
2006 /* mempool bind completed, now no need any mempools in the table */
2007 dm_table_free_md_mempools(t);
2011 * Bind a table to the device.
2013 static void event_callback(void *context)
2015 unsigned long flags;
2017 struct mapped_device *md = (struct mapped_device *) context;
2019 spin_lock_irqsave(&md->uevent_lock, flags);
2020 list_splice_init(&md->uevent_list, &uevents);
2021 spin_unlock_irqrestore(&md->uevent_lock, flags);
2023 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
2025 atomic_inc(&md->event_nr);
2026 wake_up(&md->eventq);
2029 static void __set_size(struct mapped_device *md, sector_t size)
2031 set_capacity(md->disk, size);
2033 mutex_lock(&md->bdev->bd_inode->i_mutex);
2034 i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
2035 mutex_unlock(&md->bdev->bd_inode->i_mutex);
2039 * Returns old map, which caller must destroy.
2041 static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
2042 struct queue_limits *limits)
2044 struct dm_table *old_map;
2045 struct request_queue *q = md->queue;
2047 unsigned long flags;
2049 size = dm_table_get_size(t);
2052 * Wipe any geometry if the size of the table changed.
2054 if (size != get_capacity(md->disk))
2055 memset(&md->geometry, 0, sizeof(md->geometry));
2057 __set_size(md, size);
2059 dm_table_event_callback(t, event_callback, md);
2062 * The queue hasn't been stopped yet, if the old table type wasn't
2063 * for request-based during suspension. So stop it to prevent
2064 * I/O mapping before resume.
2065 * This must be done before setting the queue restrictions,
2066 * because request-based dm may be run just after the setting.
2068 if (dm_table_request_based(t) && !blk_queue_stopped(q))
2071 __bind_mempools(md, t);
2073 write_lock_irqsave(&md->map_lock, flags);
2076 dm_table_set_restrictions(t, q, limits);
2077 write_unlock_irqrestore(&md->map_lock, flags);
2083 * Returns unbound table for the caller to free.
2085 static struct dm_table *__unbind(struct mapped_device *md)
2087 struct dm_table *map = md->map;
2088 unsigned long flags;
2093 dm_table_event_callback(map, NULL, NULL);
2094 write_lock_irqsave(&md->map_lock, flags);
2096 write_unlock_irqrestore(&md->map_lock, flags);
2102 * Constructor for a new device.
2104 int dm_create(int minor, struct mapped_device **result)
2106 struct mapped_device *md;
2108 md = alloc_dev(minor);
2118 static struct mapped_device *dm_find_md(dev_t dev)
2120 struct mapped_device *md;
2121 unsigned minor = MINOR(dev);
2123 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
2126 spin_lock(&_minor_lock);
2128 md = idr_find(&_minor_idr, minor);
2129 if (md && (md == MINOR_ALLOCED ||
2130 (MINOR(disk_devt(dm_disk(md))) != minor) ||
2131 test_bit(DMF_FREEING, &md->flags))) {
2137 spin_unlock(&_minor_lock);
2142 struct mapped_device *dm_get_md(dev_t dev)
2144 struct mapped_device *md = dm_find_md(dev);
2152 void *dm_get_mdptr(struct mapped_device *md)
2154 return md->interface_ptr;
2157 void dm_set_mdptr(struct mapped_device *md, void *ptr)
2159 md->interface_ptr = ptr;
2162 void dm_get(struct mapped_device *md)
2164 atomic_inc(&md->holders);
2167 const char *dm_device_name(struct mapped_device *md)
2171 EXPORT_SYMBOL_GPL(dm_device_name);
2173 void dm_put(struct mapped_device *md)
2175 struct dm_table *map;
2177 BUG_ON(test_bit(DMF_FREEING, &md->flags));
2179 if (atomic_dec_and_lock(&md->holders, &_minor_lock)) {
2180 map = dm_get_live_table(md);
2181 idr_replace(&_minor_idr, MINOR_ALLOCED,
2182 MINOR(disk_devt(dm_disk(md))));
2183 set_bit(DMF_FREEING, &md->flags);
2184 spin_unlock(&_minor_lock);
2185 if (!dm_suspended_md(md)) {
2186 dm_table_presuspend_targets(map);
2187 dm_table_postsuspend_targets(map);
2191 dm_table_destroy(__unbind(md));
2195 EXPORT_SYMBOL_GPL(dm_put);
2197 static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
2200 DECLARE_WAITQUEUE(wait, current);
2202 dm_unplug_all(md->queue);
2204 add_wait_queue(&md->wait, &wait);
2207 set_current_state(interruptible);
2210 if (!md_in_flight(md))
2213 if (interruptible == TASK_INTERRUPTIBLE &&
2214 signal_pending(current)) {
2221 set_current_state(TASK_RUNNING);
2223 remove_wait_queue(&md->wait, &wait);
2228 static void dm_flush(struct mapped_device *md)
2230 dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
2232 bio_init(&md->barrier_bio);
2233 md->barrier_bio.bi_bdev = md->bdev;
2234 md->barrier_bio.bi_rw = WRITE_BARRIER;
2235 __split_and_process_bio(md, &md->barrier_bio);
2237 dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
2240 static void process_barrier(struct mapped_device *md, struct bio *bio)
2242 md->barrier_error = 0;
2246 if (!bio_empty_barrier(bio)) {
2247 __split_and_process_bio(md, bio);
2251 if (md->barrier_error != DM_ENDIO_REQUEUE)
2252 bio_endio(bio, md->barrier_error);
2254 spin_lock_irq(&md->deferred_lock);
2255 bio_list_add_head(&md->deferred, bio);
2256 spin_unlock_irq(&md->deferred_lock);
2261 * Process the deferred bios
2263 static void dm_wq_work(struct work_struct *work)
2265 struct mapped_device *md = container_of(work, struct mapped_device,
2269 down_write(&md->io_lock);
2271 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
2272 spin_lock_irq(&md->deferred_lock);
2273 c = bio_list_pop(&md->deferred);
2274 spin_unlock_irq(&md->deferred_lock);
2277 clear_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
2281 up_write(&md->io_lock);
2283 if (dm_request_based(md))
2284 generic_make_request(c);
2286 if (bio_rw_flagged(c, BIO_RW_BARRIER))
2287 process_barrier(md, c);
2289 __split_and_process_bio(md, c);
2292 down_write(&md->io_lock);
2295 up_write(&md->io_lock);
2298 static void dm_queue_flush(struct mapped_device *md)
2300 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2301 smp_mb__after_clear_bit();
2302 queue_work(md->wq, &md->work);
2305 static void dm_rq_set_flush_nr(struct request *clone, unsigned flush_nr)
2307 struct dm_rq_target_io *tio = clone->end_io_data;
2309 tio->info.flush_request = flush_nr;
2312 /* Issue barrier requests to targets and wait for their completion. */
2313 static int dm_rq_barrier(struct mapped_device *md)
2316 struct dm_table *map = dm_get_live_table(md);
2317 unsigned num_targets = dm_table_get_num_targets(map);
2318 struct dm_target *ti;
2319 struct request *clone;
2321 md->barrier_error = 0;
2323 for (i = 0; i < num_targets; i++) {
2324 ti = dm_table_get_target(map, i);
2325 for (j = 0; j < ti->num_flush_requests; j++) {
2326 clone = clone_rq(md->flush_request, md, GFP_NOIO);
2327 dm_rq_set_flush_nr(clone, j);
2328 atomic_inc(&md->pending[rq_data_dir(clone)]);
2329 map_request(ti, clone, md);
2333 dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
2336 return md->barrier_error;
2339 static void dm_rq_barrier_work(struct work_struct *work)
2342 struct mapped_device *md = container_of(work, struct mapped_device,
2344 struct request_queue *q = md->queue;
2346 unsigned long flags;
2349 * Hold the md reference here and leave it at the last part so that
2350 * the md can't be deleted by device opener when the barrier request
2355 error = dm_rq_barrier(md);
2357 rq = md->flush_request;
2358 md->flush_request = NULL;
2360 if (error == DM_ENDIO_REQUEUE) {
2361 spin_lock_irqsave(q->queue_lock, flags);
2362 blk_requeue_request(q, rq);
2363 spin_unlock_irqrestore(q->queue_lock, flags);
2365 blk_end_request_all(rq, error);
2373 * Swap in a new table, returning the old one for the caller to destroy.
2375 struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
2377 struct dm_table *map = ERR_PTR(-EINVAL);
2378 struct queue_limits limits;
2381 mutex_lock(&md->suspend_lock);
2383 /* device must be suspended */
2384 if (!dm_suspended_md(md))
2387 r = dm_calculate_queue_limits(table, &limits);
2393 /* cannot change the device type, once a table is bound */
2395 (dm_table_get_type(md->map) != dm_table_get_type(table))) {
2396 DMWARN("can't change the device type after a table is bound");
2400 map = __bind(md, table, &limits);
2403 mutex_unlock(&md->suspend_lock);
2408 * Functions to lock and unlock any filesystem running on the
2411 static int lock_fs(struct mapped_device *md)
2415 WARN_ON(md->frozen_sb);
2417 md->frozen_sb = freeze_bdev(md->bdev);
2418 if (IS_ERR(md->frozen_sb)) {
2419 r = PTR_ERR(md->frozen_sb);
2420 md->frozen_sb = NULL;
2424 set_bit(DMF_FROZEN, &md->flags);
2429 static void unlock_fs(struct mapped_device *md)
2431 if (!test_bit(DMF_FROZEN, &md->flags))
2434 thaw_bdev(md->bdev, md->frozen_sb);
2435 md->frozen_sb = NULL;
2436 clear_bit(DMF_FROZEN, &md->flags);
2440 * We need to be able to change a mapping table under a mounted
2441 * filesystem. For example we might want to move some data in
2442 * the background. Before the table can be swapped with
2443 * dm_bind_table, dm_suspend must be called to flush any in
2444 * flight bios and ensure that any further io gets deferred.
2447 * Suspend mechanism in request-based dm.
2449 * 1. Flush all I/Os by lock_fs() if needed.
2450 * 2. Stop dispatching any I/O by stopping the request_queue.
2451 * 3. Wait for all in-flight I/Os to be completed or requeued.
2453 * To abort suspend, start the request_queue.
2455 int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
2457 struct dm_table *map = NULL;
2459 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
2460 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
2462 mutex_lock(&md->suspend_lock);
2464 if (dm_suspended_md(md)) {
2469 map = dm_get_live_table(md);
2472 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2473 * This flag is cleared before dm_suspend returns.
2476 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2478 /* This does not get reverted if there's an error later. */
2479 dm_table_presuspend_targets(map);
2482 * Flush I/O to the device.
2483 * Any I/O submitted after lock_fs() may not be flushed.
2484 * noflush takes precedence over do_lockfs.
2485 * (lock_fs() flushes I/Os and waits for them to complete.)
2487 if (!noflush && do_lockfs) {
2494 * Here we must make sure that no processes are submitting requests
2495 * to target drivers i.e. no one may be executing
2496 * __split_and_process_bio. This is called from dm_request and
2499 * To get all processes out of __split_and_process_bio in dm_request,
2500 * we take the write lock. To prevent any process from reentering
2501 * __split_and_process_bio from dm_request, we set
2502 * DMF_QUEUE_IO_TO_THREAD.
2504 * To quiesce the thread (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND
2505 * and call flush_workqueue(md->wq). flush_workqueue will wait until
2506 * dm_wq_work exits and DMF_BLOCK_IO_FOR_SUSPEND will prevent any
2507 * further calls to __split_and_process_bio from dm_wq_work.
2509 down_write(&md->io_lock);
2510 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2511 set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
2512 up_write(&md->io_lock);
2515 * Request-based dm uses md->wq for barrier (dm_rq_barrier_work) which
2516 * can be kicked until md->queue is stopped. So stop md->queue before
2519 if (dm_request_based(md))
2520 stop_queue(md->queue);
2522 flush_workqueue(md->wq);
2525 * At this point no more requests are entering target request routines.
2526 * We call dm_wait_for_completion to wait for all existing requests
2529 r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
2531 down_write(&md->io_lock);
2533 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2534 up_write(&md->io_lock);
2536 /* were we interrupted ? */
2540 if (dm_request_based(md))
2541 start_queue(md->queue);
2544 goto out; /* pushback list is already flushed, so skip flush */
2548 * If dm_wait_for_completion returned 0, the device is completely
2549 * quiescent now. There is no request-processing activity. All new
2550 * requests are being added to md->deferred list.
2553 set_bit(DMF_SUSPENDED, &md->flags);
2555 dm_table_postsuspend_targets(map);
2561 mutex_unlock(&md->suspend_lock);
2565 int dm_resume(struct mapped_device *md)
2568 struct dm_table *map = NULL;
2570 mutex_lock(&md->suspend_lock);
2571 if (!dm_suspended_md(md))
2574 map = dm_get_live_table(md);
2575 if (!map || !dm_table_get_size(map))
2578 r = dm_table_resume_targets(map);
2585 * Flushing deferred I/Os must be done after targets are resumed
2586 * so that mapping of targets can work correctly.
2587 * Request-based dm is queueing the deferred I/Os in its request_queue.
2589 if (dm_request_based(md))
2590 start_queue(md->queue);
2594 clear_bit(DMF_SUSPENDED, &md->flags);
2596 dm_table_unplug_all(map);
2600 mutex_unlock(&md->suspend_lock);
2605 /*-----------------------------------------------------------------
2606 * Event notification.
2607 *---------------------------------------------------------------*/
2608 void dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
2611 char udev_cookie[DM_COOKIE_LENGTH];
2612 char *envp[] = { udev_cookie, NULL };
2615 kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
2617 snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
2618 DM_COOKIE_ENV_VAR_NAME, cookie);
2619 kobject_uevent_env(&disk_to_dev(md->disk)->kobj, action, envp);
2623 uint32_t dm_next_uevent_seq(struct mapped_device *md)
2625 return atomic_add_return(1, &md->uevent_seq);
2628 uint32_t dm_get_event_nr(struct mapped_device *md)
2630 return atomic_read(&md->event_nr);
2633 int dm_wait_event(struct mapped_device *md, int event_nr)
2635 return wait_event_interruptible(md->eventq,
2636 (event_nr != atomic_read(&md->event_nr)));
2639 void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
2641 unsigned long flags;
2643 spin_lock_irqsave(&md->uevent_lock, flags);
2644 list_add(elist, &md->uevent_list);
2645 spin_unlock_irqrestore(&md->uevent_lock, flags);
2649 * The gendisk is only valid as long as you have a reference
2652 struct gendisk *dm_disk(struct mapped_device *md)
2657 struct kobject *dm_kobject(struct mapped_device *md)
2663 * struct mapped_device should not be exported outside of dm.c
2664 * so use this check to verify that kobj is part of md structure
2666 struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
2668 struct mapped_device *md;
2670 md = container_of(kobj, struct mapped_device, kobj);
2671 if (&md->kobj != kobj)
2674 if (test_bit(DMF_FREEING, &md->flags) ||
2682 int dm_suspended_md(struct mapped_device *md)
2684 return test_bit(DMF_SUSPENDED, &md->flags);
2687 int dm_suspended(struct dm_target *ti)
2689 struct mapped_device *md = dm_table_get_md(ti->table);
2690 int r = dm_suspended_md(md);
2696 EXPORT_SYMBOL_GPL(dm_suspended);
2698 int dm_noflush_suspending(struct dm_target *ti)
2700 struct mapped_device *md = dm_table_get_md(ti->table);
2701 int r = __noflush_suspending(md);
2707 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
2709 struct dm_md_mempools *dm_alloc_md_mempools(unsigned type)
2711 struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL);
2716 pools->io_pool = (type == DM_TYPE_BIO_BASED) ?
2717 mempool_create_slab_pool(MIN_IOS, _io_cache) :
2718 mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache);
2719 if (!pools->io_pool)
2720 goto free_pools_and_out;
2722 pools->tio_pool = (type == DM_TYPE_BIO_BASED) ?
2723 mempool_create_slab_pool(MIN_IOS, _tio_cache) :
2724 mempool_create_slab_pool(MIN_IOS, _rq_tio_cache);
2725 if (!pools->tio_pool)
2726 goto free_io_pool_and_out;
2728 pools->bs = (type == DM_TYPE_BIO_BASED) ?
2729 bioset_create(16, 0) : bioset_create(MIN_IOS, 0);
2731 goto free_tio_pool_and_out;
2735 free_tio_pool_and_out:
2736 mempool_destroy(pools->tio_pool);
2738 free_io_pool_and_out:
2739 mempool_destroy(pools->io_pool);
2747 void dm_free_md_mempools(struct dm_md_mempools *pools)
2753 mempool_destroy(pools->io_pool);
2755 if (pools->tio_pool)
2756 mempool_destroy(pools->tio_pool);
2759 bioset_free(pools->bs);
2764 static const struct block_device_operations dm_blk_dops = {
2765 .open = dm_blk_open,
2766 .release = dm_blk_close,
2767 .ioctl = dm_blk_ioctl,
2768 .getgeo = dm_blk_getgeo,
2769 .owner = THIS_MODULE
2772 EXPORT_SYMBOL(dm_get_mapinfo);
2777 module_init(dm_init);
2778 module_exit(dm_exit);
2780 module_param(major, uint, 0);
2781 MODULE_PARM_DESC(major, "The major number of the device mapper");
2782 MODULE_DESCRIPTION(DM_NAME " driver");
2783 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2784 MODULE_LICENSE("GPL");