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.
9 #include "dm-bio-list.h"
10 #include "dm-uevent.h"
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/moduleparam.h>
16 #include <linux/blkpg.h>
17 #include <linux/bio.h>
18 #include <linux/buffer_head.h>
19 #include <linux/mempool.h>
20 #include <linux/slab.h>
21 #include <linux/idr.h>
22 #include <linux/hdreg.h>
23 #include <linux/blktrace_api.h>
24 #include <trace/block.h>
26 #define DM_MSG_PREFIX "core"
28 static const char *_name = DM_NAME;
30 static unsigned int major = 0;
31 static unsigned int _major = 0;
33 static DEFINE_SPINLOCK(_minor_lock);
36 * One of these is allocated per bio.
39 struct mapped_device *md;
43 unsigned long start_time;
48 * One of these is allocated per target within a bio. Hopefully
49 * this will be simplified out one day.
57 DEFINE_TRACE(block_bio_complete);
60 * For request-based dm.
61 * One of these is allocated per request.
63 struct dm_rq_target_io {
64 struct mapped_device *md;
66 struct request *orig, clone;
72 * For request-based dm.
73 * One of these is allocated per bio.
75 struct dm_rq_clone_bio_info {
80 union map_info *dm_get_mapinfo(struct bio *bio)
82 if (bio && bio->bi_private)
83 return &((struct dm_target_io *)bio->bi_private)->info;
87 #define MINOR_ALLOCED ((void *)-1)
90 * Bits for the md->flags field.
92 #define DMF_BLOCK_IO 0
93 #define DMF_SUSPENDED 1
96 #define DMF_DELETING 4
97 #define DMF_NOFLUSH_SUSPENDING 5
100 * Work processed by per-device workqueue.
103 struct work_struct work;
104 struct mapped_device *md;
107 struct mapped_device {
108 struct rw_semaphore io_lock;
109 struct mutex suspend_lock;
110 spinlock_t pushback_lock;
117 struct request_queue *queue;
118 struct gendisk *disk;
124 * A list of ios that arrived while we were suspended.
127 wait_queue_head_t wait;
128 struct bio_list deferred;
129 struct bio_list pushback;
132 * Processing queue (flush/barriers)
134 struct workqueue_struct *wq;
137 * The current mapping.
139 struct dm_table *map;
142 * io objects are allocated from here.
153 wait_queue_head_t eventq;
155 struct list_head uevent_list;
156 spinlock_t uevent_lock; /* Protect access to uevent_list */
159 * freeze/thaw support require holding onto a super block
161 struct super_block *frozen_sb;
162 struct block_device *suspended_bdev;
164 /* forced geometry settings */
165 struct hd_geometry geometry;
172 static struct kmem_cache *_io_cache;
173 static struct kmem_cache *_tio_cache;
174 static struct kmem_cache *_rq_tio_cache;
175 static struct kmem_cache *_rq_bio_info_cache;
177 static int __init local_init(void)
181 /* allocate a slab for the dm_ios */
182 _io_cache = KMEM_CACHE(dm_io, 0);
186 /* allocate a slab for the target ios */
187 _tio_cache = KMEM_CACHE(dm_target_io, 0);
189 goto out_free_io_cache;
191 _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
193 goto out_free_tio_cache;
195 _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
196 if (!_rq_bio_info_cache)
197 goto out_free_rq_tio_cache;
199 r = dm_uevent_init();
201 goto out_free_rq_bio_info_cache;
204 r = register_blkdev(_major, _name);
206 goto out_uevent_exit;
215 out_free_rq_bio_info_cache:
216 kmem_cache_destroy(_rq_bio_info_cache);
217 out_free_rq_tio_cache:
218 kmem_cache_destroy(_rq_tio_cache);
220 kmem_cache_destroy(_tio_cache);
222 kmem_cache_destroy(_io_cache);
227 static void local_exit(void)
229 kmem_cache_destroy(_rq_bio_info_cache);
230 kmem_cache_destroy(_rq_tio_cache);
231 kmem_cache_destroy(_tio_cache);
232 kmem_cache_destroy(_io_cache);
233 unregister_blkdev(_major, _name);
238 DMINFO("cleaned up");
241 static int (*_inits[])(void) __initdata = {
250 static void (*_exits[])(void) = {
259 static int __init dm_init(void)
261 const int count = ARRAY_SIZE(_inits);
265 for (i = 0; i < count; i++) {
280 static void __exit dm_exit(void)
282 int i = ARRAY_SIZE(_exits);
289 * Block device functions
291 static int dm_blk_open(struct block_device *bdev, fmode_t mode)
293 struct mapped_device *md;
295 spin_lock(&_minor_lock);
297 md = bdev->bd_disk->private_data;
301 if (test_bit(DMF_FREEING, &md->flags) ||
302 test_bit(DMF_DELETING, &md->flags)) {
308 atomic_inc(&md->open_count);
311 spin_unlock(&_minor_lock);
313 return md ? 0 : -ENXIO;
316 static int dm_blk_close(struct gendisk *disk, fmode_t mode)
318 struct mapped_device *md = disk->private_data;
319 atomic_dec(&md->open_count);
324 int dm_open_count(struct mapped_device *md)
326 return atomic_read(&md->open_count);
330 * Guarantees nothing is using the device before it's deleted.
332 int dm_lock_for_deletion(struct mapped_device *md)
336 spin_lock(&_minor_lock);
338 if (dm_open_count(md))
341 set_bit(DMF_DELETING, &md->flags);
343 spin_unlock(&_minor_lock);
348 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
350 struct mapped_device *md = bdev->bd_disk->private_data;
352 return dm_get_geometry(md, geo);
355 static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
356 unsigned int cmd, unsigned long arg)
358 struct mapped_device *md = bdev->bd_disk->private_data;
359 struct dm_table *map = dm_get_table(md);
360 struct dm_target *tgt;
363 if (!map || !dm_table_get_size(map))
366 /* We only support devices that have a single target */
367 if (dm_table_get_num_targets(map) != 1)
370 tgt = dm_table_get_target(map, 0);
372 if (dm_suspended(md)) {
377 if (tgt->type->ioctl)
378 r = tgt->type->ioctl(tgt, cmd, arg);
386 static struct dm_io *alloc_io(struct mapped_device *md)
388 return mempool_alloc(md->io_pool, GFP_NOIO);
391 static void free_io(struct mapped_device *md, struct dm_io *io)
393 mempool_free(io, md->io_pool);
396 static struct dm_target_io *alloc_tio(struct mapped_device *md)
398 return mempool_alloc(md->tio_pool, GFP_NOIO);
401 static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
403 mempool_free(tio, md->tio_pool);
406 static void start_io_acct(struct dm_io *io)
408 struct mapped_device *md = io->md;
411 io->start_time = jiffies;
413 cpu = part_stat_lock();
414 part_round_stats(cpu, &dm_disk(md)->part0);
416 dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending);
419 static void end_io_acct(struct dm_io *io)
421 struct mapped_device *md = io->md;
422 struct bio *bio = io->bio;
423 unsigned long duration = jiffies - io->start_time;
425 int rw = bio_data_dir(bio);
427 cpu = part_stat_lock();
428 part_round_stats(cpu, &dm_disk(md)->part0);
429 part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
432 dm_disk(md)->part0.in_flight = pending =
433 atomic_dec_return(&md->pending);
435 /* nudge anyone waiting on suspend queue */
441 * Add the bio to the list of deferred io.
443 static int queue_io(struct mapped_device *md, struct bio *bio)
445 down_write(&md->io_lock);
447 if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
448 up_write(&md->io_lock);
452 bio_list_add(&md->deferred, bio);
454 up_write(&md->io_lock);
455 return 0; /* deferred successfully */
459 * Everyone (including functions in this file), should use this
460 * function to access the md->map field, and make sure they call
461 * dm_table_put() when finished.
463 struct dm_table *dm_get_table(struct mapped_device *md)
467 read_lock(&md->map_lock);
471 read_unlock(&md->map_lock);
477 * Get the geometry associated with a dm device
479 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
487 * Set the geometry of a device.
489 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
491 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
493 if (geo->start > sz) {
494 DMWARN("Start sector is beyond the geometry limits.");
503 /*-----------------------------------------------------------------
505 * A more elegant soln is in the works that uses the queue
506 * merge fn, unfortunately there are a couple of changes to
507 * the block layer that I want to make for this. So in the
508 * interests of getting something for people to use I give
509 * you this clearly demarcated crap.
510 *---------------------------------------------------------------*/
512 static int __noflush_suspending(struct mapped_device *md)
514 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
518 * Decrements the number of outstanding ios that a bio has been
519 * cloned into, completing the original io if necc.
521 static void dec_pending(struct dm_io *io, int error)
526 struct mapped_device *md = io->md;
528 /* Push-back supersedes any I/O errors */
529 if (error && !(io->error > 0 && __noflush_suspending(md)))
532 if (atomic_dec_and_test(&io->io_count)) {
533 if (io->error == DM_ENDIO_REQUEUE) {
535 * Target requested pushing back the I/O.
536 * This must be handled before the sleeper on
537 * suspend queue merges the pushback list.
539 spin_lock_irqsave(&md->pushback_lock, flags);
540 if (__noflush_suspending(md))
541 bio_list_add(&md->pushback, io->bio);
543 /* noflush suspend was interrupted. */
545 spin_unlock_irqrestore(&md->pushback_lock, flags);
550 io_error = io->error;
555 if (io_error != DM_ENDIO_REQUEUE) {
556 trace_block_bio_complete(md->queue, bio);
558 bio_endio(bio, io_error);
563 static void clone_endio(struct bio *bio, int error)
566 struct dm_target_io *tio = bio->bi_private;
567 struct dm_io *io = tio->io;
568 struct mapped_device *md = tio->io->md;
569 dm_endio_fn endio = tio->ti->type->end_io;
571 if (!bio_flagged(bio, BIO_UPTODATE) && !error)
575 r = endio(tio->ti, bio, error, &tio->info);
576 if (r < 0 || r == DM_ENDIO_REQUEUE)
578 * error and requeue request are handled
582 else if (r == DM_ENDIO_INCOMPLETE)
583 /* The target will handle the io */
586 DMWARN("unimplemented target endio return value: %d", r);
592 * Store md for cleanup instead of tio which is about to get freed.
594 bio->bi_private = md->bs;
598 dec_pending(io, error);
601 static sector_t max_io_len(struct mapped_device *md,
602 sector_t sector, struct dm_target *ti)
604 sector_t offset = sector - ti->begin;
605 sector_t len = ti->len - offset;
608 * Does the target need to split even further ?
612 boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
621 static void __map_bio(struct dm_target *ti, struct bio *clone,
622 struct dm_target_io *tio)
626 struct mapped_device *md;
631 BUG_ON(!clone->bi_size);
633 clone->bi_end_io = clone_endio;
634 clone->bi_private = tio;
637 * Map the clone. If r == 0 we don't need to do
638 * anything, the target has assumed ownership of
641 atomic_inc(&tio->io->io_count);
642 sector = clone->bi_sector;
643 r = ti->type->map(ti, clone, &tio->info);
644 if (r == DM_MAPIO_REMAPPED) {
645 /* the bio has been remapped so dispatch it */
647 trace_block_remap(bdev_get_queue(clone->bi_bdev), clone,
648 tio->io->bio->bi_bdev->bd_dev,
649 clone->bi_sector, sector);
651 generic_make_request(clone);
652 } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
653 /* error the io and bail out, or requeue it if needed */
655 dec_pending(tio->io, r);
657 * Store bio_set for cleanup.
659 clone->bi_private = md->bs;
663 DMWARN("unimplemented target map return value: %d", r);
669 struct mapped_device *md;
670 struct dm_table *map;
674 sector_t sector_count;
678 static void dm_bio_destructor(struct bio *bio)
680 struct bio_set *bs = bio->bi_private;
686 * Creates a little bio that is just does part of a bvec.
688 static struct bio *split_bvec(struct bio *bio, sector_t sector,
689 unsigned short idx, unsigned int offset,
690 unsigned int len, struct bio_set *bs)
693 struct bio_vec *bv = bio->bi_io_vec + idx;
695 clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
696 clone->bi_destructor = dm_bio_destructor;
697 *clone->bi_io_vec = *bv;
699 clone->bi_sector = sector;
700 clone->bi_bdev = bio->bi_bdev;
701 clone->bi_rw = bio->bi_rw;
703 clone->bi_size = to_bytes(len);
704 clone->bi_io_vec->bv_offset = offset;
705 clone->bi_io_vec->bv_len = clone->bi_size;
706 clone->bi_flags |= 1 << BIO_CLONED;
712 * Creates a bio that consists of range of complete bvecs.
714 static struct bio *clone_bio(struct bio *bio, sector_t sector,
715 unsigned short idx, unsigned short bv_count,
716 unsigned int len, struct bio_set *bs)
720 clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
721 __bio_clone(clone, bio);
722 clone->bi_destructor = dm_bio_destructor;
723 clone->bi_sector = sector;
725 clone->bi_vcnt = idx + bv_count;
726 clone->bi_size = to_bytes(len);
727 clone->bi_flags &= ~(1 << BIO_SEG_VALID);
732 static int __clone_and_map(struct clone_info *ci)
734 struct bio *clone, *bio = ci->bio;
735 struct dm_target *ti;
736 sector_t len = 0, max;
737 struct dm_target_io *tio;
739 ti = dm_table_find_target(ci->map, ci->sector);
740 if (!dm_target_is_valid(ti))
743 max = max_io_len(ci->md, ci->sector, ti);
746 * Allocate a target io object.
748 tio = alloc_tio(ci->md);
751 memset(&tio->info, 0, sizeof(tio->info));
753 if (ci->sector_count <= max) {
755 * Optimise for the simple case where we can do all of
756 * the remaining io with a single clone.
758 clone = clone_bio(bio, ci->sector, ci->idx,
759 bio->bi_vcnt - ci->idx, ci->sector_count,
761 __map_bio(ti, clone, tio);
762 ci->sector_count = 0;
764 } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
766 * There are some bvecs that don't span targets.
767 * Do as many of these as possible.
770 sector_t remaining = max;
773 for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
774 bv_len = to_sector(bio->bi_io_vec[i].bv_len);
776 if (bv_len > remaining)
783 clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len,
785 __map_bio(ti, clone, tio);
788 ci->sector_count -= len;
793 * Handle a bvec that must be split between two or more targets.
795 struct bio_vec *bv = bio->bi_io_vec + ci->idx;
796 sector_t remaining = to_sector(bv->bv_len);
797 unsigned int offset = 0;
801 ti = dm_table_find_target(ci->map, ci->sector);
802 if (!dm_target_is_valid(ti))
805 max = max_io_len(ci->md, ci->sector, ti);
807 tio = alloc_tio(ci->md);
810 memset(&tio->info, 0, sizeof(tio->info));
813 len = min(remaining, max);
815 clone = split_bvec(bio, ci->sector, ci->idx,
816 bv->bv_offset + offset, len,
819 __map_bio(ti, clone, tio);
822 ci->sector_count -= len;
823 offset += to_bytes(len);
824 } while (remaining -= len);
833 * Split the bio into several clones.
835 static int __split_bio(struct mapped_device *md, struct bio *bio)
837 struct clone_info ci;
840 ci.map = dm_get_table(md);
841 if (unlikely(!ci.map))
843 if (unlikely(bio_barrier(bio) && !dm_table_barrier_ok(ci.map))) {
844 dm_table_put(ci.map);
845 bio_endio(bio, -EOPNOTSUPP);
850 ci.io = alloc_io(md);
852 atomic_set(&ci.io->io_count, 1);
855 ci.sector = bio->bi_sector;
856 ci.sector_count = bio_sectors(bio);
857 ci.idx = bio->bi_idx;
859 start_io_acct(ci.io);
860 while (ci.sector_count && !error)
861 error = __clone_and_map(&ci);
863 /* drop the extra reference count */
864 dec_pending(ci.io, error);
865 dm_table_put(ci.map);
869 /*-----------------------------------------------------------------
871 *---------------------------------------------------------------*/
873 static int dm_merge_bvec(struct request_queue *q,
874 struct bvec_merge_data *bvm,
875 struct bio_vec *biovec)
877 struct mapped_device *md = q->queuedata;
878 struct dm_table *map = dm_get_table(md);
879 struct dm_target *ti;
880 sector_t max_sectors;
886 ti = dm_table_find_target(map, bvm->bi_sector);
887 if (!dm_target_is_valid(ti))
891 * Find maximum amount of I/O that won't need splitting
893 max_sectors = min(max_io_len(md, bvm->bi_sector, ti),
894 (sector_t) BIO_MAX_SECTORS);
895 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
900 * merge_bvec_fn() returns number of bytes
901 * it can accept at this offset
902 * max is precomputed maximal io size
904 if (max_size && ti->type->merge)
905 max_size = ti->type->merge(ti, bvm, biovec, max_size);
912 * Always allow an entire first page
914 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
915 max_size = biovec->bv_len;
921 * The request function that just remaps the bio built up by
924 static int dm_request(struct request_queue *q, struct bio *bio)
927 int rw = bio_data_dir(bio);
928 struct mapped_device *md = q->queuedata;
931 down_read(&md->io_lock);
933 cpu = part_stat_lock();
934 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
935 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
939 * If we're suspended we have to queue
942 while (test_bit(DMF_BLOCK_IO, &md->flags)) {
943 up_read(&md->io_lock);
945 if (bio_rw(bio) != READA)
946 r = queue_io(md, bio);
952 * We're in a while loop, because someone could suspend
953 * before we get to the following read lock.
955 down_read(&md->io_lock);
958 r = __split_bio(md, bio);
959 up_read(&md->io_lock);
968 static void dm_unplug_all(struct request_queue *q)
970 struct mapped_device *md = q->queuedata;
971 struct dm_table *map = dm_get_table(md);
974 dm_table_unplug_all(map);
979 static int dm_any_congested(void *congested_data, int bdi_bits)
982 struct mapped_device *md = congested_data;
983 struct dm_table *map;
985 if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
986 map = dm_get_table(md);
988 r = dm_table_any_congested(map, bdi_bits);
996 /*-----------------------------------------------------------------
997 * An IDR is used to keep track of allocated minor numbers.
998 *---------------------------------------------------------------*/
999 static DEFINE_IDR(_minor_idr);
1001 static void free_minor(int minor)
1003 spin_lock(&_minor_lock);
1004 idr_remove(&_minor_idr, minor);
1005 spin_unlock(&_minor_lock);
1009 * See if the device with a specific minor # is free.
1011 static int specific_minor(int minor)
1015 if (minor >= (1 << MINORBITS))
1018 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1022 spin_lock(&_minor_lock);
1024 if (idr_find(&_minor_idr, minor)) {
1029 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
1034 idr_remove(&_minor_idr, m);
1040 spin_unlock(&_minor_lock);
1044 static int next_free_minor(int *minor)
1048 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1052 spin_lock(&_minor_lock);
1054 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
1058 if (m >= (1 << MINORBITS)) {
1059 idr_remove(&_minor_idr, m);
1067 spin_unlock(&_minor_lock);
1071 static struct block_device_operations dm_blk_dops;
1074 * Allocate and initialise a blank device with a given minor.
1076 static struct mapped_device *alloc_dev(int minor)
1079 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
1083 DMWARN("unable to allocate device, out of memory.");
1087 if (!try_module_get(THIS_MODULE))
1088 goto bad_module_get;
1090 /* get a minor number for the dev */
1091 if (minor == DM_ANY_MINOR)
1092 r = next_free_minor(&minor);
1094 r = specific_minor(minor);
1098 init_rwsem(&md->io_lock);
1099 mutex_init(&md->suspend_lock);
1100 spin_lock_init(&md->pushback_lock);
1101 rwlock_init(&md->map_lock);
1102 atomic_set(&md->holders, 1);
1103 atomic_set(&md->open_count, 0);
1104 atomic_set(&md->event_nr, 0);
1105 atomic_set(&md->uevent_seq, 0);
1106 INIT_LIST_HEAD(&md->uevent_list);
1107 spin_lock_init(&md->uevent_lock);
1109 md->queue = blk_alloc_queue(GFP_KERNEL);
1113 md->queue->queuedata = md;
1114 md->queue->backing_dev_info.congested_fn = dm_any_congested;
1115 md->queue->backing_dev_info.congested_data = md;
1116 blk_queue_make_request(md->queue, dm_request);
1117 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
1118 md->queue->unplug_fn = dm_unplug_all;
1119 blk_queue_merge_bvec(md->queue, dm_merge_bvec);
1121 md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
1125 md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
1129 md->bs = bioset_create(16, 0);
1133 md->disk = alloc_disk(1);
1137 atomic_set(&md->pending, 0);
1138 init_waitqueue_head(&md->wait);
1139 init_waitqueue_head(&md->eventq);
1141 md->disk->major = _major;
1142 md->disk->first_minor = minor;
1143 md->disk->fops = &dm_blk_dops;
1144 md->disk->queue = md->queue;
1145 md->disk->private_data = md;
1146 sprintf(md->disk->disk_name, "dm-%d", minor);
1148 format_dev_t(md->name, MKDEV(_major, minor));
1150 md->wq = create_singlethread_workqueue("kdmflush");
1154 /* Populate the mapping, nobody knows we exist yet */
1155 spin_lock(&_minor_lock);
1156 old_md = idr_replace(&_minor_idr, md, minor);
1157 spin_unlock(&_minor_lock);
1159 BUG_ON(old_md != MINOR_ALLOCED);
1166 bioset_free(md->bs);
1168 mempool_destroy(md->tio_pool);
1170 mempool_destroy(md->io_pool);
1172 blk_cleanup_queue(md->queue);
1176 module_put(THIS_MODULE);
1182 static void unlock_fs(struct mapped_device *md);
1184 static void free_dev(struct mapped_device *md)
1186 int minor = MINOR(disk_devt(md->disk));
1188 if (md->suspended_bdev) {
1190 bdput(md->suspended_bdev);
1192 destroy_workqueue(md->wq);
1193 mempool_destroy(md->tio_pool);
1194 mempool_destroy(md->io_pool);
1195 bioset_free(md->bs);
1196 del_gendisk(md->disk);
1199 spin_lock(&_minor_lock);
1200 md->disk->private_data = NULL;
1201 spin_unlock(&_minor_lock);
1204 blk_cleanup_queue(md->queue);
1205 module_put(THIS_MODULE);
1210 * Bind a table to the device.
1212 static void event_callback(void *context)
1214 unsigned long flags;
1216 struct mapped_device *md = (struct mapped_device *) context;
1218 spin_lock_irqsave(&md->uevent_lock, flags);
1219 list_splice_init(&md->uevent_list, &uevents);
1220 spin_unlock_irqrestore(&md->uevent_lock, flags);
1222 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
1224 atomic_inc(&md->event_nr);
1225 wake_up(&md->eventq);
1228 static void __set_size(struct mapped_device *md, sector_t size)
1230 set_capacity(md->disk, size);
1232 mutex_lock(&md->suspended_bdev->bd_inode->i_mutex);
1233 i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
1234 mutex_unlock(&md->suspended_bdev->bd_inode->i_mutex);
1237 static int __bind(struct mapped_device *md, struct dm_table *t)
1239 struct request_queue *q = md->queue;
1242 size = dm_table_get_size(t);
1245 * Wipe any geometry if the size of the table changed.
1247 if (size != get_capacity(md->disk))
1248 memset(&md->geometry, 0, sizeof(md->geometry));
1250 if (md->suspended_bdev)
1251 __set_size(md, size);
1254 dm_table_destroy(t);
1258 dm_table_event_callback(t, event_callback, md);
1260 write_lock(&md->map_lock);
1262 dm_table_set_restrictions(t, q);
1263 write_unlock(&md->map_lock);
1268 static void __unbind(struct mapped_device *md)
1270 struct dm_table *map = md->map;
1275 dm_table_event_callback(map, NULL, NULL);
1276 write_lock(&md->map_lock);
1278 write_unlock(&md->map_lock);
1279 dm_table_destroy(map);
1283 * Constructor for a new device.
1285 int dm_create(int minor, struct mapped_device **result)
1287 struct mapped_device *md;
1289 md = alloc_dev(minor);
1299 static struct mapped_device *dm_find_md(dev_t dev)
1301 struct mapped_device *md;
1302 unsigned minor = MINOR(dev);
1304 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
1307 spin_lock(&_minor_lock);
1309 md = idr_find(&_minor_idr, minor);
1310 if (md && (md == MINOR_ALLOCED ||
1311 (MINOR(disk_devt(dm_disk(md))) != minor) ||
1312 test_bit(DMF_FREEING, &md->flags))) {
1318 spin_unlock(&_minor_lock);
1323 struct mapped_device *dm_get_md(dev_t dev)
1325 struct mapped_device *md = dm_find_md(dev);
1333 void *dm_get_mdptr(struct mapped_device *md)
1335 return md->interface_ptr;
1338 void dm_set_mdptr(struct mapped_device *md, void *ptr)
1340 md->interface_ptr = ptr;
1343 void dm_get(struct mapped_device *md)
1345 atomic_inc(&md->holders);
1348 const char *dm_device_name(struct mapped_device *md)
1352 EXPORT_SYMBOL_GPL(dm_device_name);
1354 void dm_put(struct mapped_device *md)
1356 struct dm_table *map;
1358 BUG_ON(test_bit(DMF_FREEING, &md->flags));
1360 if (atomic_dec_and_lock(&md->holders, &_minor_lock)) {
1361 map = dm_get_table(md);
1362 idr_replace(&_minor_idr, MINOR_ALLOCED,
1363 MINOR(disk_devt(dm_disk(md))));
1364 set_bit(DMF_FREEING, &md->flags);
1365 spin_unlock(&_minor_lock);
1366 if (!dm_suspended(md)) {
1367 dm_table_presuspend_targets(map);
1368 dm_table_postsuspend_targets(map);
1376 EXPORT_SYMBOL_GPL(dm_put);
1378 static int dm_wait_for_completion(struct mapped_device *md)
1383 set_current_state(TASK_INTERRUPTIBLE);
1386 if (!atomic_read(&md->pending))
1389 if (signal_pending(current)) {
1396 set_current_state(TASK_RUNNING);
1402 * Process the deferred bios
1404 static void __flush_deferred_io(struct mapped_device *md)
1408 while ((c = bio_list_pop(&md->deferred))) {
1409 if (__split_bio(md, c))
1413 clear_bit(DMF_BLOCK_IO, &md->flags);
1416 static void __merge_pushback_list(struct mapped_device *md)
1418 unsigned long flags;
1420 spin_lock_irqsave(&md->pushback_lock, flags);
1421 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
1422 bio_list_merge_head(&md->deferred, &md->pushback);
1423 bio_list_init(&md->pushback);
1424 spin_unlock_irqrestore(&md->pushback_lock, flags);
1427 static void dm_wq_work(struct work_struct *work)
1429 struct dm_wq_req *req = container_of(work, struct dm_wq_req, work);
1430 struct mapped_device *md = req->md;
1432 down_write(&md->io_lock);
1433 __flush_deferred_io(md);
1434 up_write(&md->io_lock);
1437 static void dm_wq_queue(struct mapped_device *md, struct dm_wq_req *req)
1440 INIT_WORK(&req->work, dm_wq_work);
1441 queue_work(md->wq, &req->work);
1444 static void dm_queue_flush(struct mapped_device *md)
1446 struct dm_wq_req req;
1448 dm_wq_queue(md, &req);
1449 flush_workqueue(md->wq);
1453 * Swap in a new table (destroying old one).
1455 int dm_swap_table(struct mapped_device *md, struct dm_table *table)
1459 mutex_lock(&md->suspend_lock);
1461 /* device must be suspended */
1462 if (!dm_suspended(md))
1465 /* without bdev, the device size cannot be changed */
1466 if (!md->suspended_bdev)
1467 if (get_capacity(md->disk) != dm_table_get_size(table))
1471 r = __bind(md, table);
1474 mutex_unlock(&md->suspend_lock);
1479 * Functions to lock and unlock any filesystem running on the
1482 static int lock_fs(struct mapped_device *md)
1486 WARN_ON(md->frozen_sb);
1488 md->frozen_sb = freeze_bdev(md->suspended_bdev);
1489 if (IS_ERR(md->frozen_sb)) {
1490 r = PTR_ERR(md->frozen_sb);
1491 md->frozen_sb = NULL;
1495 set_bit(DMF_FROZEN, &md->flags);
1497 /* don't bdput right now, we don't want the bdev
1498 * to go away while it is locked.
1503 static void unlock_fs(struct mapped_device *md)
1505 if (!test_bit(DMF_FROZEN, &md->flags))
1508 thaw_bdev(md->suspended_bdev, md->frozen_sb);
1509 md->frozen_sb = NULL;
1510 clear_bit(DMF_FROZEN, &md->flags);
1514 * We need to be able to change a mapping table under a mounted
1515 * filesystem. For example we might want to move some data in
1516 * the background. Before the table can be swapped with
1517 * dm_bind_table, dm_suspend must be called to flush any in
1518 * flight bios and ensure that any further io gets deferred.
1520 int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
1522 struct dm_table *map = NULL;
1523 DECLARE_WAITQUEUE(wait, current);
1525 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
1526 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
1528 mutex_lock(&md->suspend_lock);
1530 if (dm_suspended(md)) {
1535 map = dm_get_table(md);
1538 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
1539 * This flag is cleared before dm_suspend returns.
1542 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
1544 /* This does not get reverted if there's an error later. */
1545 dm_table_presuspend_targets(map);
1547 /* bdget() can stall if the pending I/Os are not flushed */
1549 md->suspended_bdev = bdget_disk(md->disk, 0);
1550 if (!md->suspended_bdev) {
1551 DMWARN("bdget failed in dm_suspend");
1557 * Flush I/O to the device. noflush supersedes do_lockfs,
1558 * because lock_fs() needs to flush I/Os.
1568 * First we set the BLOCK_IO flag so no more ios will be mapped.
1570 down_write(&md->io_lock);
1571 set_bit(DMF_BLOCK_IO, &md->flags);
1573 add_wait_queue(&md->wait, &wait);
1574 up_write(&md->io_lock);
1578 dm_table_unplug_all(map);
1581 * Wait for the already-mapped ios to complete.
1583 r = dm_wait_for_completion(md);
1585 down_write(&md->io_lock);
1586 remove_wait_queue(&md->wait, &wait);
1589 __merge_pushback_list(md);
1590 up_write(&md->io_lock);
1592 /* were we interrupted ? */
1597 goto out; /* pushback list is already flushed, so skip flush */
1600 dm_table_postsuspend_targets(map);
1602 set_bit(DMF_SUSPENDED, &md->flags);
1605 if (r && md->suspended_bdev) {
1606 bdput(md->suspended_bdev);
1607 md->suspended_bdev = NULL;
1613 mutex_unlock(&md->suspend_lock);
1617 int dm_resume(struct mapped_device *md)
1620 struct dm_table *map = NULL;
1622 mutex_lock(&md->suspend_lock);
1623 if (!dm_suspended(md))
1626 map = dm_get_table(md);
1627 if (!map || !dm_table_get_size(map))
1630 r = dm_table_resume_targets(map);
1638 if (md->suspended_bdev) {
1639 bdput(md->suspended_bdev);
1640 md->suspended_bdev = NULL;
1643 clear_bit(DMF_SUSPENDED, &md->flags);
1645 dm_table_unplug_all(map);
1647 dm_kobject_uevent(md);
1653 mutex_unlock(&md->suspend_lock);
1658 /*-----------------------------------------------------------------
1659 * Event notification.
1660 *---------------------------------------------------------------*/
1661 void dm_kobject_uevent(struct mapped_device *md)
1663 kobject_uevent(&disk_to_dev(md->disk)->kobj, KOBJ_CHANGE);
1666 uint32_t dm_next_uevent_seq(struct mapped_device *md)
1668 return atomic_add_return(1, &md->uevent_seq);
1671 uint32_t dm_get_event_nr(struct mapped_device *md)
1673 return atomic_read(&md->event_nr);
1676 int dm_wait_event(struct mapped_device *md, int event_nr)
1678 return wait_event_interruptible(md->eventq,
1679 (event_nr != atomic_read(&md->event_nr)));
1682 void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
1684 unsigned long flags;
1686 spin_lock_irqsave(&md->uevent_lock, flags);
1687 list_add(elist, &md->uevent_list);
1688 spin_unlock_irqrestore(&md->uevent_lock, flags);
1692 * The gendisk is only valid as long as you have a reference
1695 struct gendisk *dm_disk(struct mapped_device *md)
1700 struct kobject *dm_kobject(struct mapped_device *md)
1706 * struct mapped_device should not be exported outside of dm.c
1707 * so use this check to verify that kobj is part of md structure
1709 struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
1711 struct mapped_device *md;
1713 md = container_of(kobj, struct mapped_device, kobj);
1714 if (&md->kobj != kobj)
1721 int dm_suspended(struct mapped_device *md)
1723 return test_bit(DMF_SUSPENDED, &md->flags);
1726 int dm_noflush_suspending(struct dm_target *ti)
1728 struct mapped_device *md = dm_table_get_md(ti->table);
1729 int r = __noflush_suspending(md);
1735 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
1737 static struct block_device_operations dm_blk_dops = {
1738 .open = dm_blk_open,
1739 .release = dm_blk_close,
1740 .ioctl = dm_blk_ioctl,
1741 .getgeo = dm_blk_getgeo,
1742 .owner = THIS_MODULE
1745 EXPORT_SYMBOL(dm_get_mapinfo);
1750 module_init(dm_init);
1751 module_exit(dm_exit);
1753 module_param(major, uint, 0);
1754 MODULE_PARM_DESC(major, "The major number of the device mapper");
1755 MODULE_DESCRIPTION(DM_NAME " driver");
1756 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
1757 MODULE_LICENSE("GPL");