2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004-2006 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 <linux/smp_lock.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);
35 * One of these is allocated per bio.
38 struct mapped_device *md;
42 unsigned long start_time;
46 * One of these is allocated per target within a bio. Hopefully
47 * this will be simplified out one day.
55 union map_info *dm_get_mapinfo(struct bio *bio)
57 if (bio && bio->bi_private)
58 return &((struct dm_target_io *)bio->bi_private)->info;
62 #define MINOR_ALLOCED ((void *)-1)
65 * Bits for the md->flags field.
67 #define DMF_BLOCK_IO 0
68 #define DMF_SUSPENDED 1
71 #define DMF_DELETING 4
72 #define DMF_NOFLUSH_SUSPENDING 5
75 * Work processed by per-device workqueue.
82 struct work_struct work;
83 struct mapped_device *md;
87 struct mapped_device {
88 struct rw_semaphore io_lock;
89 struct mutex suspend_lock;
90 spinlock_t pushback_lock;
97 struct request_queue *queue;
104 * A list of ios that arrived while we were suspended.
107 wait_queue_head_t wait;
108 struct bio_list deferred;
109 struct bio_list pushback;
112 * Processing queue (flush/barriers)
114 struct workqueue_struct *wq;
117 * The current mapping.
119 struct dm_table *map;
122 * io objects are allocated from here.
133 wait_queue_head_t eventq;
135 struct list_head uevent_list;
136 spinlock_t uevent_lock; /* Protect access to uevent_list */
139 * freeze/thaw support require holding onto a super block
141 struct super_block *frozen_sb;
142 struct block_device *suspended_bdev;
144 /* forced geometry settings */
145 struct hd_geometry geometry;
149 static struct kmem_cache *_io_cache;
150 static struct kmem_cache *_tio_cache;
152 static int __init local_init(void)
156 /* allocate a slab for the dm_ios */
157 _io_cache = KMEM_CACHE(dm_io, 0);
161 /* allocate a slab for the target ios */
162 _tio_cache = KMEM_CACHE(dm_target_io, 0);
164 kmem_cache_destroy(_io_cache);
168 r = dm_uevent_init();
170 kmem_cache_destroy(_tio_cache);
171 kmem_cache_destroy(_io_cache);
176 r = register_blkdev(_major, _name);
178 kmem_cache_destroy(_tio_cache);
179 kmem_cache_destroy(_io_cache);
190 static void local_exit(void)
192 kmem_cache_destroy(_tio_cache);
193 kmem_cache_destroy(_io_cache);
194 unregister_blkdev(_major, _name);
199 DMINFO("cleaned up");
202 static int (*_inits[])(void) __initdata = {
211 static void (*_exits[])(void) = {
220 static int __init dm_init(void)
222 const int count = ARRAY_SIZE(_inits);
226 for (i = 0; i < count; i++) {
241 static void __exit dm_exit(void)
243 int i = ARRAY_SIZE(_exits);
250 * Block device functions
252 static int dm_blk_open(struct inode *inode, struct file *file)
254 struct mapped_device *md;
256 spin_lock(&_minor_lock);
258 md = inode->i_bdev->bd_disk->private_data;
262 if (test_bit(DMF_FREEING, &md->flags) ||
263 test_bit(DMF_DELETING, &md->flags)) {
269 atomic_inc(&md->open_count);
272 spin_unlock(&_minor_lock);
274 return md ? 0 : -ENXIO;
277 static int dm_blk_close(struct inode *inode, struct file *file)
279 struct mapped_device *md;
281 md = inode->i_bdev->bd_disk->private_data;
282 atomic_dec(&md->open_count);
287 int dm_open_count(struct mapped_device *md)
289 return atomic_read(&md->open_count);
293 * Guarantees nothing is using the device before it's deleted.
295 int dm_lock_for_deletion(struct mapped_device *md)
299 spin_lock(&_minor_lock);
301 if (dm_open_count(md))
304 set_bit(DMF_DELETING, &md->flags);
306 spin_unlock(&_minor_lock);
311 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
313 struct mapped_device *md = bdev->bd_disk->private_data;
315 return dm_get_geometry(md, geo);
318 static int dm_blk_ioctl(struct inode *inode, struct file *file,
319 unsigned int cmd, unsigned long arg)
321 struct mapped_device *md;
322 struct dm_table *map;
323 struct dm_target *tgt;
326 /* We don't really need this lock, but we do need 'inode'. */
329 md = inode->i_bdev->bd_disk->private_data;
331 map = dm_get_table(md);
333 if (!map || !dm_table_get_size(map))
336 /* We only support devices that have a single target */
337 if (dm_table_get_num_targets(map) != 1)
340 tgt = dm_table_get_target(map, 0);
342 if (dm_suspended(md)) {
347 if (tgt->type->ioctl)
348 r = tgt->type->ioctl(tgt, inode, file, cmd, arg);
357 static struct dm_io *alloc_io(struct mapped_device *md)
359 return mempool_alloc(md->io_pool, GFP_NOIO);
362 static void free_io(struct mapped_device *md, struct dm_io *io)
364 mempool_free(io, md->io_pool);
367 static struct dm_target_io *alloc_tio(struct mapped_device *md)
369 return mempool_alloc(md->tio_pool, GFP_NOIO);
372 static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
374 mempool_free(tio, md->tio_pool);
377 static void start_io_acct(struct dm_io *io)
379 struct mapped_device *md = io->md;
382 io->start_time = jiffies;
384 cpu = part_stat_lock();
385 part_round_stats(cpu, &dm_disk(md)->part0);
387 dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending);
390 static int end_io_acct(struct dm_io *io)
392 struct mapped_device *md = io->md;
393 struct bio *bio = io->bio;
394 unsigned long duration = jiffies - io->start_time;
396 int rw = bio_data_dir(bio);
398 cpu = part_stat_lock();
399 part_round_stats(cpu, &dm_disk(md)->part0);
400 part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
403 dm_disk(md)->part0.in_flight = pending =
404 atomic_dec_return(&md->pending);
410 * Add the bio to the list of deferred io.
412 static int queue_io(struct mapped_device *md, struct bio *bio)
414 down_write(&md->io_lock);
416 if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
417 up_write(&md->io_lock);
421 bio_list_add(&md->deferred, bio);
423 up_write(&md->io_lock);
424 return 0; /* deferred successfully */
428 * Everyone (including functions in this file), should use this
429 * function to access the md->map field, and make sure they call
430 * dm_table_put() when finished.
432 struct dm_table *dm_get_table(struct mapped_device *md)
436 read_lock(&md->map_lock);
440 read_unlock(&md->map_lock);
446 * Get the geometry associated with a dm device
448 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
456 * Set the geometry of a device.
458 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
460 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
462 if (geo->start > sz) {
463 DMWARN("Start sector is beyond the geometry limits.");
472 /*-----------------------------------------------------------------
474 * A more elegant soln is in the works that uses the queue
475 * merge fn, unfortunately there are a couple of changes to
476 * the block layer that I want to make for this. So in the
477 * interests of getting something for people to use I give
478 * you this clearly demarcated crap.
479 *---------------------------------------------------------------*/
481 static int __noflush_suspending(struct mapped_device *md)
483 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
487 * Decrements the number of outstanding ios that a bio has been
488 * cloned into, completing the original io if necc.
490 static void dec_pending(struct dm_io *io, int error)
494 /* Push-back supersedes any I/O errors */
495 if (error && !(io->error > 0 && __noflush_suspending(io->md)))
498 if (atomic_dec_and_test(&io->io_count)) {
499 if (io->error == DM_ENDIO_REQUEUE) {
501 * Target requested pushing back the I/O.
502 * This must be handled before the sleeper on
503 * suspend queue merges the pushback list.
505 spin_lock_irqsave(&io->md->pushback_lock, flags);
506 if (__noflush_suspending(io->md))
507 bio_list_add(&io->md->pushback, io->bio);
509 /* noflush suspend was interrupted. */
511 spin_unlock_irqrestore(&io->md->pushback_lock, flags);
515 /* nudge anyone waiting on suspend queue */
516 wake_up(&io->md->wait);
518 if (io->error != DM_ENDIO_REQUEUE) {
519 blk_add_trace_bio(io->md->queue, io->bio,
522 bio_endio(io->bio, io->error);
529 static void clone_endio(struct bio *bio, int error)
532 struct dm_target_io *tio = bio->bi_private;
533 struct mapped_device *md = tio->io->md;
534 dm_endio_fn endio = tio->ti->type->end_io;
536 if (!bio_flagged(bio, BIO_UPTODATE) && !error)
540 r = endio(tio->ti, bio, error, &tio->info);
541 if (r < 0 || r == DM_ENDIO_REQUEUE)
543 * error and requeue request are handled
547 else if (r == DM_ENDIO_INCOMPLETE)
548 /* The target will handle the io */
551 DMWARN("unimplemented target endio return value: %d", r);
556 dec_pending(tio->io, error);
559 * Store md for cleanup instead of tio which is about to get freed.
561 bio->bi_private = md->bs;
567 static sector_t max_io_len(struct mapped_device *md,
568 sector_t sector, struct dm_target *ti)
570 sector_t offset = sector - ti->begin;
571 sector_t len = ti->len - offset;
574 * Does the target need to split even further ?
578 boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
587 static void __map_bio(struct dm_target *ti, struct bio *clone,
588 struct dm_target_io *tio)
592 struct mapped_device *md;
597 BUG_ON(!clone->bi_size);
599 clone->bi_end_io = clone_endio;
600 clone->bi_private = tio;
603 * Map the clone. If r == 0 we don't need to do
604 * anything, the target has assumed ownership of
607 atomic_inc(&tio->io->io_count);
608 sector = clone->bi_sector;
609 r = ti->type->map(ti, clone, &tio->info);
610 if (r == DM_MAPIO_REMAPPED) {
611 /* the bio has been remapped so dispatch it */
613 blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
614 tio->io->bio->bi_bdev->bd_dev,
615 clone->bi_sector, sector);
617 generic_make_request(clone);
618 } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
619 /* error the io and bail out, or requeue it if needed */
621 dec_pending(tio->io, r);
623 * Store bio_set for cleanup.
625 clone->bi_private = md->bs;
629 DMWARN("unimplemented target map return value: %d", r);
635 struct mapped_device *md;
636 struct dm_table *map;
640 sector_t sector_count;
644 static void dm_bio_destructor(struct bio *bio)
646 struct bio_set *bs = bio->bi_private;
652 * Creates a little bio that is just does part of a bvec.
654 static struct bio *split_bvec(struct bio *bio, sector_t sector,
655 unsigned short idx, unsigned int offset,
656 unsigned int len, struct bio_set *bs)
659 struct bio_vec *bv = bio->bi_io_vec + idx;
661 clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
662 clone->bi_destructor = dm_bio_destructor;
663 *clone->bi_io_vec = *bv;
665 clone->bi_sector = sector;
666 clone->bi_bdev = bio->bi_bdev;
667 clone->bi_rw = bio->bi_rw;
669 clone->bi_size = to_bytes(len);
670 clone->bi_io_vec->bv_offset = offset;
671 clone->bi_io_vec->bv_len = clone->bi_size;
672 clone->bi_flags |= 1 << BIO_CLONED;
678 * Creates a bio that consists of range of complete bvecs.
680 static struct bio *clone_bio(struct bio *bio, sector_t sector,
681 unsigned short idx, unsigned short bv_count,
682 unsigned int len, struct bio_set *bs)
686 clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
687 __bio_clone(clone, bio);
688 clone->bi_destructor = dm_bio_destructor;
689 clone->bi_sector = sector;
691 clone->bi_vcnt = idx + bv_count;
692 clone->bi_size = to_bytes(len);
693 clone->bi_flags &= ~(1 << BIO_SEG_VALID);
698 static int __clone_and_map(struct clone_info *ci)
700 struct bio *clone, *bio = ci->bio;
701 struct dm_target *ti;
702 sector_t len = 0, max;
703 struct dm_target_io *tio;
705 ti = dm_table_find_target(ci->map, ci->sector);
706 if (!dm_target_is_valid(ti))
709 max = max_io_len(ci->md, ci->sector, ti);
712 * Allocate a target io object.
714 tio = alloc_tio(ci->md);
717 memset(&tio->info, 0, sizeof(tio->info));
719 if (ci->sector_count <= max) {
721 * Optimise for the simple case where we can do all of
722 * the remaining io with a single clone.
724 clone = clone_bio(bio, ci->sector, ci->idx,
725 bio->bi_vcnt - ci->idx, ci->sector_count,
727 __map_bio(ti, clone, tio);
728 ci->sector_count = 0;
730 } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
732 * There are some bvecs that don't span targets.
733 * Do as many of these as possible.
736 sector_t remaining = max;
739 for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
740 bv_len = to_sector(bio->bi_io_vec[i].bv_len);
742 if (bv_len > remaining)
749 clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len,
751 __map_bio(ti, clone, tio);
754 ci->sector_count -= len;
759 * Handle a bvec that must be split between two or more targets.
761 struct bio_vec *bv = bio->bi_io_vec + ci->idx;
762 sector_t remaining = to_sector(bv->bv_len);
763 unsigned int offset = 0;
767 ti = dm_table_find_target(ci->map, ci->sector);
768 if (!dm_target_is_valid(ti))
771 max = max_io_len(ci->md, ci->sector, ti);
773 tio = alloc_tio(ci->md);
776 memset(&tio->info, 0, sizeof(tio->info));
779 len = min(remaining, max);
781 clone = split_bvec(bio, ci->sector, ci->idx,
782 bv->bv_offset + offset, len,
785 __map_bio(ti, clone, tio);
788 ci->sector_count -= len;
789 offset += to_bytes(len);
790 } while (remaining -= len);
799 * Split the bio into several clones.
801 static int __split_bio(struct mapped_device *md, struct bio *bio)
803 struct clone_info ci;
806 ci.map = dm_get_table(md);
807 if (unlikely(!ci.map))
812 ci.io = alloc_io(md);
814 atomic_set(&ci.io->io_count, 1);
817 ci.sector = bio->bi_sector;
818 ci.sector_count = bio_sectors(bio);
819 ci.idx = bio->bi_idx;
821 start_io_acct(ci.io);
822 while (ci.sector_count && !error)
823 error = __clone_and_map(&ci);
825 /* drop the extra reference count */
826 dec_pending(ci.io, error);
827 dm_table_put(ci.map);
831 /*-----------------------------------------------------------------
833 *---------------------------------------------------------------*/
835 static int dm_merge_bvec(struct request_queue *q,
836 struct bvec_merge_data *bvm,
837 struct bio_vec *biovec)
839 struct mapped_device *md = q->queuedata;
840 struct dm_table *map = dm_get_table(md);
841 struct dm_target *ti;
842 sector_t max_sectors;
848 ti = dm_table_find_target(map, bvm->bi_sector);
849 if (!dm_target_is_valid(ti))
853 * Find maximum amount of I/O that won't need splitting
855 max_sectors = min(max_io_len(md, bvm->bi_sector, ti),
856 (sector_t) BIO_MAX_SECTORS);
857 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
862 * merge_bvec_fn() returns number of bytes
863 * it can accept at this offset
864 * max is precomputed maximal io size
866 if (max_size && ti->type->merge)
867 max_size = ti->type->merge(ti, bvm, biovec, max_size);
874 * Always allow an entire first page
876 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
877 max_size = biovec->bv_len;
883 * The request function that just remaps the bio built up by
886 static int dm_request(struct request_queue *q, struct bio *bio)
889 int rw = bio_data_dir(bio);
890 struct mapped_device *md = q->queuedata;
894 * There is no use in forwarding any barrier request since we can't
895 * guarantee it is (or can be) handled by the targets correctly.
897 if (unlikely(bio_barrier(bio))) {
898 bio_endio(bio, -EOPNOTSUPP);
902 down_read(&md->io_lock);
904 cpu = part_stat_lock();
905 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
906 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
910 * If we're suspended we have to queue
913 while (test_bit(DMF_BLOCK_IO, &md->flags)) {
914 up_read(&md->io_lock);
916 if (bio_rw(bio) != READA)
917 r = queue_io(md, bio);
923 * We're in a while loop, because someone could suspend
924 * before we get to the following read lock.
926 down_read(&md->io_lock);
929 r = __split_bio(md, bio);
930 up_read(&md->io_lock);
939 static void dm_unplug_all(struct request_queue *q)
941 struct mapped_device *md = q->queuedata;
942 struct dm_table *map = dm_get_table(md);
945 dm_table_unplug_all(map);
950 static int dm_any_congested(void *congested_data, int bdi_bits)
953 struct mapped_device *md = (struct mapped_device *) congested_data;
954 struct dm_table *map = dm_get_table(md);
956 if (!map || test_bit(DMF_BLOCK_IO, &md->flags))
959 r = dm_table_any_congested(map, bdi_bits);
965 /*-----------------------------------------------------------------
966 * An IDR is used to keep track of allocated minor numbers.
967 *---------------------------------------------------------------*/
968 static DEFINE_IDR(_minor_idr);
970 static void free_minor(int minor)
972 spin_lock(&_minor_lock);
973 idr_remove(&_minor_idr, minor);
974 spin_unlock(&_minor_lock);
978 * See if the device with a specific minor # is free.
980 static int specific_minor(int minor)
984 if (minor >= (1 << MINORBITS))
987 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
991 spin_lock(&_minor_lock);
993 if (idr_find(&_minor_idr, minor)) {
998 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
1003 idr_remove(&_minor_idr, m);
1009 spin_unlock(&_minor_lock);
1013 static int next_free_minor(int *minor)
1017 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1021 spin_lock(&_minor_lock);
1023 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
1027 if (m >= (1 << MINORBITS)) {
1028 idr_remove(&_minor_idr, m);
1036 spin_unlock(&_minor_lock);
1040 static struct block_device_operations dm_blk_dops;
1043 * Allocate and initialise a blank device with a given minor.
1045 static struct mapped_device *alloc_dev(int minor)
1048 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
1052 DMWARN("unable to allocate device, out of memory.");
1056 if (!try_module_get(THIS_MODULE))
1057 goto bad_module_get;
1059 /* get a minor number for the dev */
1060 if (minor == DM_ANY_MINOR)
1061 r = next_free_minor(&minor);
1063 r = specific_minor(minor);
1067 init_rwsem(&md->io_lock);
1068 mutex_init(&md->suspend_lock);
1069 spin_lock_init(&md->pushback_lock);
1070 rwlock_init(&md->map_lock);
1071 atomic_set(&md->holders, 1);
1072 atomic_set(&md->open_count, 0);
1073 atomic_set(&md->event_nr, 0);
1074 atomic_set(&md->uevent_seq, 0);
1075 INIT_LIST_HEAD(&md->uevent_list);
1076 spin_lock_init(&md->uevent_lock);
1078 md->queue = blk_alloc_queue(GFP_KERNEL);
1082 md->queue->queuedata = md;
1083 md->queue->backing_dev_info.congested_fn = dm_any_congested;
1084 md->queue->backing_dev_info.congested_data = md;
1085 blk_queue_make_request(md->queue, dm_request);
1086 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
1087 md->queue->unplug_fn = dm_unplug_all;
1088 blk_queue_merge_bvec(md->queue, dm_merge_bvec);
1090 md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
1094 md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
1098 md->bs = bioset_create(16, 16);
1102 md->disk = alloc_disk(1);
1106 atomic_set(&md->pending, 0);
1107 init_waitqueue_head(&md->wait);
1108 init_waitqueue_head(&md->eventq);
1110 md->disk->major = _major;
1111 md->disk->first_minor = minor;
1112 md->disk->fops = &dm_blk_dops;
1113 md->disk->queue = md->queue;
1114 md->disk->private_data = md;
1115 sprintf(md->disk->disk_name, "dm-%d", minor);
1117 format_dev_t(md->name, MKDEV(_major, minor));
1119 md->wq = create_singlethread_workqueue("kdmflush");
1123 /* Populate the mapping, nobody knows we exist yet */
1124 spin_lock(&_minor_lock);
1125 old_md = idr_replace(&_minor_idr, md, minor);
1126 spin_unlock(&_minor_lock);
1128 BUG_ON(old_md != MINOR_ALLOCED);
1135 bioset_free(md->bs);
1137 mempool_destroy(md->tio_pool);
1139 mempool_destroy(md->io_pool);
1141 blk_cleanup_queue(md->queue);
1145 module_put(THIS_MODULE);
1151 static void unlock_fs(struct mapped_device *md);
1153 static void free_dev(struct mapped_device *md)
1155 int minor = MINOR(disk_devt(md->disk));
1157 if (md->suspended_bdev) {
1159 bdput(md->suspended_bdev);
1161 destroy_workqueue(md->wq);
1162 mempool_destroy(md->tio_pool);
1163 mempool_destroy(md->io_pool);
1164 bioset_free(md->bs);
1165 del_gendisk(md->disk);
1168 spin_lock(&_minor_lock);
1169 md->disk->private_data = NULL;
1170 spin_unlock(&_minor_lock);
1173 blk_cleanup_queue(md->queue);
1174 module_put(THIS_MODULE);
1179 * Bind a table to the device.
1181 static void event_callback(void *context)
1183 unsigned long flags;
1185 struct mapped_device *md = (struct mapped_device *) context;
1187 spin_lock_irqsave(&md->uevent_lock, flags);
1188 list_splice_init(&md->uevent_list, &uevents);
1189 spin_unlock_irqrestore(&md->uevent_lock, flags);
1191 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
1193 atomic_inc(&md->event_nr);
1194 wake_up(&md->eventq);
1197 static void __set_size(struct mapped_device *md, sector_t size)
1199 set_capacity(md->disk, size);
1201 mutex_lock(&md->suspended_bdev->bd_inode->i_mutex);
1202 i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
1203 mutex_unlock(&md->suspended_bdev->bd_inode->i_mutex);
1206 static int __bind(struct mapped_device *md, struct dm_table *t)
1208 struct request_queue *q = md->queue;
1211 size = dm_table_get_size(t);
1214 * Wipe any geometry if the size of the table changed.
1216 if (size != get_capacity(md->disk))
1217 memset(&md->geometry, 0, sizeof(md->geometry));
1219 if (md->suspended_bdev)
1220 __set_size(md, size);
1225 dm_table_event_callback(t, event_callback, md);
1227 write_lock(&md->map_lock);
1229 dm_table_set_restrictions(t, q);
1230 write_unlock(&md->map_lock);
1235 static void __unbind(struct mapped_device *md)
1237 struct dm_table *map = md->map;
1242 dm_table_event_callback(map, NULL, NULL);
1243 write_lock(&md->map_lock);
1245 write_unlock(&md->map_lock);
1250 * Constructor for a new device.
1252 int dm_create(int minor, struct mapped_device **result)
1254 struct mapped_device *md;
1256 md = alloc_dev(minor);
1264 static struct mapped_device *dm_find_md(dev_t dev)
1266 struct mapped_device *md;
1267 unsigned minor = MINOR(dev);
1269 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
1272 spin_lock(&_minor_lock);
1274 md = idr_find(&_minor_idr, minor);
1275 if (md && (md == MINOR_ALLOCED ||
1276 (MINOR(disk_devt(dm_disk(md))) != minor) ||
1277 test_bit(DMF_FREEING, &md->flags))) {
1283 spin_unlock(&_minor_lock);
1288 struct mapped_device *dm_get_md(dev_t dev)
1290 struct mapped_device *md = dm_find_md(dev);
1298 void *dm_get_mdptr(struct mapped_device *md)
1300 return md->interface_ptr;
1303 void dm_set_mdptr(struct mapped_device *md, void *ptr)
1305 md->interface_ptr = ptr;
1308 void dm_get(struct mapped_device *md)
1310 atomic_inc(&md->holders);
1313 const char *dm_device_name(struct mapped_device *md)
1317 EXPORT_SYMBOL_GPL(dm_device_name);
1319 void dm_put(struct mapped_device *md)
1321 struct dm_table *map;
1323 BUG_ON(test_bit(DMF_FREEING, &md->flags));
1325 if (atomic_dec_and_lock(&md->holders, &_minor_lock)) {
1326 map = dm_get_table(md);
1327 idr_replace(&_minor_idr, MINOR_ALLOCED,
1328 MINOR(disk_devt(dm_disk(md))));
1329 set_bit(DMF_FREEING, &md->flags);
1330 spin_unlock(&_minor_lock);
1331 if (!dm_suspended(md)) {
1332 dm_table_presuspend_targets(map);
1333 dm_table_postsuspend_targets(map);
1340 EXPORT_SYMBOL_GPL(dm_put);
1342 static int dm_wait_for_completion(struct mapped_device *md)
1347 set_current_state(TASK_INTERRUPTIBLE);
1350 if (!atomic_read(&md->pending))
1353 if (signal_pending(current)) {
1360 set_current_state(TASK_RUNNING);
1366 * Process the deferred bios
1368 static void __flush_deferred_io(struct mapped_device *md)
1372 while ((c = bio_list_pop(&md->deferred))) {
1373 if (__split_bio(md, c))
1377 clear_bit(DMF_BLOCK_IO, &md->flags);
1380 static void __merge_pushback_list(struct mapped_device *md)
1382 unsigned long flags;
1384 spin_lock_irqsave(&md->pushback_lock, flags);
1385 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
1386 bio_list_merge_head(&md->deferred, &md->pushback);
1387 bio_list_init(&md->pushback);
1388 spin_unlock_irqrestore(&md->pushback_lock, flags);
1391 static void dm_wq_work(struct work_struct *work)
1393 struct dm_wq_req *req = container_of(work, struct dm_wq_req, work);
1394 struct mapped_device *md = req->md;
1396 down_write(&md->io_lock);
1397 switch (req->type) {
1398 case DM_WQ_FLUSH_ALL:
1399 __merge_pushback_list(md);
1401 case DM_WQ_FLUSH_DEFERRED:
1402 __flush_deferred_io(md);
1405 DMERR("dm_wq_work: unrecognised work type %d", req->type);
1408 up_write(&md->io_lock);
1411 static void dm_wq_queue(struct mapped_device *md, int type, void *context,
1412 struct dm_wq_req *req)
1416 req->context = context;
1417 INIT_WORK(&req->work, dm_wq_work);
1418 queue_work(md->wq, &req->work);
1421 static void dm_queue_flush(struct mapped_device *md, int type, void *context)
1423 struct dm_wq_req req;
1425 dm_wq_queue(md, type, context, &req);
1426 flush_workqueue(md->wq);
1430 * Swap in a new table (destroying old one).
1432 int dm_swap_table(struct mapped_device *md, struct dm_table *table)
1436 mutex_lock(&md->suspend_lock);
1438 /* device must be suspended */
1439 if (!dm_suspended(md))
1442 /* without bdev, the device size cannot be changed */
1443 if (!md->suspended_bdev)
1444 if (get_capacity(md->disk) != dm_table_get_size(table))
1448 r = __bind(md, table);
1451 mutex_unlock(&md->suspend_lock);
1456 * Functions to lock and unlock any filesystem running on the
1459 static int lock_fs(struct mapped_device *md)
1463 WARN_ON(md->frozen_sb);
1465 md->frozen_sb = freeze_bdev(md->suspended_bdev);
1466 if (IS_ERR(md->frozen_sb)) {
1467 r = PTR_ERR(md->frozen_sb);
1468 md->frozen_sb = NULL;
1472 set_bit(DMF_FROZEN, &md->flags);
1474 /* don't bdput right now, we don't want the bdev
1475 * to go away while it is locked.
1480 static void unlock_fs(struct mapped_device *md)
1482 if (!test_bit(DMF_FROZEN, &md->flags))
1485 thaw_bdev(md->suspended_bdev, md->frozen_sb);
1486 md->frozen_sb = NULL;
1487 clear_bit(DMF_FROZEN, &md->flags);
1491 * We need to be able to change a mapping table under a mounted
1492 * filesystem. For example we might want to move some data in
1493 * the background. Before the table can be swapped with
1494 * dm_bind_table, dm_suspend must be called to flush any in
1495 * flight bios and ensure that any further io gets deferred.
1497 int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
1499 struct dm_table *map = NULL;
1500 DECLARE_WAITQUEUE(wait, current);
1502 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
1503 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
1505 mutex_lock(&md->suspend_lock);
1507 if (dm_suspended(md)) {
1512 map = dm_get_table(md);
1515 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
1516 * This flag is cleared before dm_suspend returns.
1519 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
1521 /* This does not get reverted if there's an error later. */
1522 dm_table_presuspend_targets(map);
1524 /* bdget() can stall if the pending I/Os are not flushed */
1526 md->suspended_bdev = bdget_disk(md->disk, 0);
1527 if (!md->suspended_bdev) {
1528 DMWARN("bdget failed in dm_suspend");
1534 * Flush I/O to the device. noflush supersedes do_lockfs,
1535 * because lock_fs() needs to flush I/Os.
1545 * First we set the BLOCK_IO flag so no more ios will be mapped.
1547 down_write(&md->io_lock);
1548 set_bit(DMF_BLOCK_IO, &md->flags);
1550 add_wait_queue(&md->wait, &wait);
1551 up_write(&md->io_lock);
1555 dm_table_unplug_all(map);
1558 * Wait for the already-mapped ios to complete.
1560 r = dm_wait_for_completion(md);
1562 down_write(&md->io_lock);
1563 remove_wait_queue(&md->wait, &wait);
1566 __merge_pushback_list(md);
1567 up_write(&md->io_lock);
1569 /* were we interrupted ? */
1571 dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
1574 goto out; /* pushback list is already flushed, so skip flush */
1577 dm_table_postsuspend_targets(map);
1579 set_bit(DMF_SUSPENDED, &md->flags);
1584 * Because there may be already I/Os in the pushback list,
1585 * flush them before return.
1587 dm_queue_flush(md, DM_WQ_FLUSH_ALL, NULL);
1590 if (r && md->suspended_bdev) {
1591 bdput(md->suspended_bdev);
1592 md->suspended_bdev = NULL;
1598 mutex_unlock(&md->suspend_lock);
1602 int dm_resume(struct mapped_device *md)
1605 struct dm_table *map = NULL;
1607 mutex_lock(&md->suspend_lock);
1608 if (!dm_suspended(md))
1611 map = dm_get_table(md);
1612 if (!map || !dm_table_get_size(map))
1615 r = dm_table_resume_targets(map);
1619 dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
1623 if (md->suspended_bdev) {
1624 bdput(md->suspended_bdev);
1625 md->suspended_bdev = NULL;
1628 clear_bit(DMF_SUSPENDED, &md->flags);
1630 dm_table_unplug_all(map);
1632 dm_kobject_uevent(md);
1638 mutex_unlock(&md->suspend_lock);
1643 /*-----------------------------------------------------------------
1644 * Event notification.
1645 *---------------------------------------------------------------*/
1646 void dm_kobject_uevent(struct mapped_device *md)
1648 kobject_uevent(&disk_to_dev(md->disk)->kobj, KOBJ_CHANGE);
1651 uint32_t dm_next_uevent_seq(struct mapped_device *md)
1653 return atomic_add_return(1, &md->uevent_seq);
1656 uint32_t dm_get_event_nr(struct mapped_device *md)
1658 return atomic_read(&md->event_nr);
1661 int dm_wait_event(struct mapped_device *md, int event_nr)
1663 return wait_event_interruptible(md->eventq,
1664 (event_nr != atomic_read(&md->event_nr)));
1667 void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
1669 unsigned long flags;
1671 spin_lock_irqsave(&md->uevent_lock, flags);
1672 list_add(elist, &md->uevent_list);
1673 spin_unlock_irqrestore(&md->uevent_lock, flags);
1677 * The gendisk is only valid as long as you have a reference
1680 struct gendisk *dm_disk(struct mapped_device *md)
1685 int dm_suspended(struct mapped_device *md)
1687 return test_bit(DMF_SUSPENDED, &md->flags);
1690 int dm_noflush_suspending(struct dm_target *ti)
1692 struct mapped_device *md = dm_table_get_md(ti->table);
1693 int r = __noflush_suspending(md);
1699 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
1701 static struct block_device_operations dm_blk_dops = {
1702 .open = dm_blk_open,
1703 .release = dm_blk_close,
1704 .ioctl = dm_blk_ioctl,
1705 .getgeo = dm_blk_getgeo,
1706 .owner = THIS_MODULE
1709 EXPORT_SYMBOL(dm_get_mapinfo);
1714 module_init(dm_init);
1715 module_exit(dm_exit);
1717 module_param(major, uint, 0);
1718 MODULE_PARM_DESC(major, "The major number of the device mapper");
1719 MODULE_DESCRIPTION(DM_NAME " driver");
1720 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
1721 MODULE_LICENSE("GPL");