/* * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. */ #include "dm.h" #include "dm-bio-list.h" #include <linux/init.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/moduleparam.h> #include <linux/blkpg.h> #include <linux/bio.h> #include <linux/buffer_head.h> #include <linux/mempool.h> #include <linux/slab.h> #include <linux/idr.h> #include <linux/hdreg.h> #include <linux/blktrace_api.h> #include <linux/smp_lock.h> #define DM_MSG_PREFIX "core" static const char *_name = DM_NAME; static unsigned int major = 0; static unsigned int _major = 0; static DEFINE_SPINLOCK(_minor_lock); /* * One of these is allocated per bio. */ struct dm_io { struct mapped_device *md; int error; struct bio *bio; atomic_t io_count; unsigned long start_time; }; /* * One of these is allocated per target within a bio. Hopefully * this will be simplified out one day. */ struct dm_target_io { struct dm_io *io; struct dm_target *ti; union map_info info; }; union map_info *dm_get_mapinfo(struct bio *bio) { if (bio && bio->bi_private) return &((struct dm_target_io *)bio->bi_private)->info; return NULL; } #define MINOR_ALLOCED ((void *)-1) /* * Bits for the md->flags field. */ #define DMF_BLOCK_IO 0 #define DMF_SUSPENDED 1 #define DMF_FROZEN 2 #define DMF_FREEING 3 #define DMF_DELETING 4 #define DMF_NOFLUSH_SUSPENDING 5 struct mapped_device { struct rw_semaphore io_lock; struct semaphore suspend_lock; spinlock_t pushback_lock; rwlock_t map_lock; atomic_t holders; atomic_t open_count; unsigned long flags; struct request_queue *queue; struct gendisk *disk; char name[16]; void *interface_ptr; /* * A list of ios that arrived while we were suspended. */ atomic_t pending; wait_queue_head_t wait; struct bio_list deferred; struct bio_list pushback; /* * The current mapping. */ struct dm_table *map; /* * io objects are allocated from here. */ mempool_t *io_pool; mempool_t *tio_pool; struct bio_set *bs; /* * Event handling. */ atomic_t event_nr; wait_queue_head_t eventq; /* * freeze/thaw support require holding onto a super block */ struct super_block *frozen_sb; struct block_device *suspended_bdev; /* forced geometry settings */ struct hd_geometry geometry; }; #define MIN_IOS 256 static struct kmem_cache *_io_cache; static struct kmem_cache *_tio_cache; static int __init local_init(void) { int r; /* allocate a slab for the dm_ios */ _io_cache = KMEM_CACHE(dm_io, 0); if (!_io_cache) return -ENOMEM; /* allocate a slab for the target ios */ _tio_cache = KMEM_CACHE(dm_target_io, 0); if (!_tio_cache) { kmem_cache_destroy(_io_cache); return -ENOMEM; } _major = major; r = register_blkdev(_major, _name); if (r < 0) { kmem_cache_destroy(_tio_cache); kmem_cache_destroy(_io_cache); return r; } if (!_major) _major = r; return 0; } static void local_exit(void) { kmem_cache_destroy(_tio_cache); kmem_cache_destroy(_io_cache); unregister_blkdev(_major, _name); _major = 0; DMINFO("cleaned up"); } int (*_inits[])(void) __initdata = { local_init, dm_target_init, dm_linear_init, dm_stripe_init, dm_interface_init, }; void (*_exits[])(void) = { local_exit, dm_target_exit, dm_linear_exit, dm_stripe_exit, dm_interface_exit, }; static int __init dm_init(void) { const int count = ARRAY_SIZE(_inits); int r, i; for (i = 0; i < count; i++) { r = _inits[i](); if (r) goto bad; } return 0; bad: while (i--) _exits[i](); return r; } static void __exit dm_exit(void) { int i = ARRAY_SIZE(_exits); while (i--) _exits[i](); } /* * Block device functions */ static int dm_blk_open(struct inode *inode, struct file *file) { struct mapped_device *md; spin_lock(&_minor_lock); md = inode->i_bdev->bd_disk->private_data; if (!md) goto out; if (test_bit(DMF_FREEING, &md->flags) || test_bit(DMF_DELETING, &md->flags)) { md = NULL; goto out; } dm_get(md); atomic_inc(&md->open_count); out: spin_unlock(&_minor_lock); return md ? 0 : -ENXIO; } static int dm_blk_close(struct inode *inode, struct file *file) { struct mapped_device *md; md = inode->i_bdev->bd_disk->private_data; atomic_dec(&md->open_count); dm_put(md); return 0; } int dm_open_count(struct mapped_device *md) { return atomic_read(&md->open_count); } /* * Guarantees nothing is using the device before it's deleted. */ int dm_lock_for_deletion(struct mapped_device *md) { int r = 0; spin_lock(&_minor_lock); if (dm_open_count(md)) r = -EBUSY; else set_bit(DMF_DELETING, &md->flags); spin_unlock(&_minor_lock); return r; } static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo) { struct mapped_device *md = bdev->bd_disk->private_data; return dm_get_geometry(md, geo); } static int dm_blk_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { struct mapped_device *md; struct dm_table *map; struct dm_target *tgt; int r = -ENOTTY; /* We don't really need this lock, but we do need 'inode'. */ unlock_kernel(); md = inode->i_bdev->bd_disk->private_data; map = dm_get_table(md); if (!map || !dm_table_get_size(map)) goto out; /* We only support devices that have a single target */ if (dm_table_get_num_targets(map) != 1) goto out; tgt = dm_table_get_target(map, 0); if (dm_suspended(md)) { r = -EAGAIN; goto out; } if (tgt->type->ioctl) r = tgt->type->ioctl(tgt, inode, file, cmd, arg); out: dm_table_put(map); lock_kernel(); return r; } static struct dm_io *alloc_io(struct mapped_device *md) { return mempool_alloc(md->io_pool, GFP_NOIO); } static void free_io(struct mapped_device *md, struct dm_io *io) { mempool_free(io, md->io_pool); } static struct dm_target_io *alloc_tio(struct mapped_device *md) { return mempool_alloc(md->tio_pool, GFP_NOIO); } static void free_tio(struct mapped_device *md, struct dm_target_io *tio) { mempool_free(tio, md->tio_pool); } static void start_io_acct(struct dm_io *io) { struct mapped_device *md = io->md; io->start_time = jiffies; preempt_disable(); disk_round_stats(dm_disk(md)); preempt_enable(); dm_disk(md)->in_flight = atomic_inc_return(&md->pending); } static int end_io_acct(struct dm_io *io) { struct mapped_device *md = io->md; struct bio *bio = io->bio; unsigned long duration = jiffies - io->start_time; int pending; int rw = bio_data_dir(bio); preempt_disable(); disk_round_stats(dm_disk(md)); preempt_enable(); dm_disk(md)->in_flight = pending = atomic_dec_return(&md->pending); disk_stat_add(dm_disk(md), ticks[rw], duration); return !pending; } /* * Add the bio to the list of deferred io. */ static int queue_io(struct mapped_device *md, struct bio *bio) { down_write(&md->io_lock); if (!test_bit(DMF_BLOCK_IO, &md->flags)) { up_write(&md->io_lock); return 1; } bio_list_add(&md->deferred, bio); up_write(&md->io_lock); return 0; /* deferred successfully */ } /* * Everyone (including functions in this file), should use this * function to access the md->map field, and make sure they call * dm_table_put() when finished. */ struct dm_table *dm_get_table(struct mapped_device *md) { struct dm_table *t; read_lock(&md->map_lock); t = md->map; if (t) dm_table_get(t); read_unlock(&md->map_lock); return t; } /* * Get the geometry associated with a dm device */ int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo) { *geo = md->geometry; return 0; } /* * Set the geometry of a device. */ int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo) { sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors; if (geo->start > sz) { DMWARN("Start sector is beyond the geometry limits."); return -EINVAL; } md->geometry = *geo; return 0; } /*----------------------------------------------------------------- * CRUD START: * A more elegant soln is in the works that uses the queue * merge fn, unfortunately there are a couple of changes to * the block layer that I want to make for this. So in the * interests of getting something for people to use I give * you this clearly demarcated crap. *---------------------------------------------------------------*/ static int __noflush_suspending(struct mapped_device *md) { return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); } /* * Decrements the number of outstanding ios that a bio has been * cloned into, completing the original io if necc. */ static void dec_pending(struct dm_io *io, int error) { unsigned long flags; /* Push-back supersedes any I/O errors */ if (error && !(io->error > 0 && __noflush_suspending(io->md))) io->error = error; if (atomic_dec_and_test(&io->io_count)) { if (io->error == DM_ENDIO_REQUEUE) { /* * Target requested pushing back the I/O. * This must be handled before the sleeper on * suspend queue merges the pushback list. */ spin_lock_irqsave(&io->md->pushback_lock, flags); if (__noflush_suspending(io->md)) bio_list_add(&io->md->pushback, io->bio); else /* noflush suspend was interrupted. */ io->error = -EIO; spin_unlock_irqrestore(&io->md->pushback_lock, flags); } if (end_io_acct(io)) /* nudge anyone waiting on suspend queue */ wake_up(&io->md->wait); if (io->error != DM_ENDIO_REQUEUE) { blk_add_trace_bio(io->md->queue, io->bio, BLK_TA_COMPLETE); bio_endio(io->bio, io->bio->bi_size, io->error); } free_io(io->md, io); } } static int clone_endio(struct bio *bio, unsigned int done, int error) { int r = 0; struct dm_target_io *tio = bio->bi_private; struct mapped_device *md = tio->io->md; dm_endio_fn endio = tio->ti->type->end_io; if (bio->bi_size) return 1; if (!bio_flagged(bio, BIO_UPTODATE) && !error) error = -EIO; if (endio) { r = endio(tio->ti, bio, error, &tio->info); if (r < 0 || r == DM_ENDIO_REQUEUE) /* * error and requeue request are handled * in dec_pending(). */ error = r; else if (r == DM_ENDIO_INCOMPLETE) /* The target will handle the io */ return 1; else if (r) { DMWARN("unimplemented target endio return value: %d", r); BUG(); } } dec_pending(tio->io, error); /* * Store md for cleanup instead of tio which is about to get freed. */ bio->bi_private = md->bs; bio_put(bio); free_tio(md, tio); return r; } static sector_t max_io_len(struct mapped_device *md, sector_t sector, struct dm_target *ti) { sector_t offset = sector - ti->begin; sector_t len = ti->len - offset; /* * Does the target need to split even further ? */ if (ti->split_io) { sector_t boundary; boundary = ((offset + ti->split_io) & ~(ti->split_io - 1)) - offset; if (len > boundary) len = boundary; } return len; } static void __map_bio(struct dm_target *ti, struct bio *clone, struct dm_target_io *tio) { int r; sector_t sector; struct mapped_device *md; /* * Sanity checks. */ BUG_ON(!clone->bi_size); clone->bi_end_io = clone_endio; clone->bi_private = tio; /* * Map the clone. If r == 0 we don't need to do * anything, the target has assumed ownership of * this io. */ atomic_inc(&tio->io->io_count); sector = clone->bi_sector; r = ti->type->map(ti, clone, &tio->info); if (r == DM_MAPIO_REMAPPED) { /* the bio has been remapped so dispatch it */ blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone, tio->io->bio->bi_bdev->bd_dev, sector, clone->bi_sector); generic_make_request(clone); } else if (r < 0 || r == DM_MAPIO_REQUEUE) { /* error the io and bail out, or requeue it if needed */ md = tio->io->md; dec_pending(tio->io, r); /* * Store bio_set for cleanup. */ clone->bi_private = md->bs; bio_put(clone); free_tio(md, tio); } else if (r) { DMWARN("unimplemented target map return value: %d", r); BUG(); } } struct clone_info { struct mapped_device *md; struct dm_table *map; struct bio *bio; struct dm_io *io; sector_t sector; sector_t sector_count; unsigned short idx; }; static void dm_bio_destructor(struct bio *bio) { struct bio_set *bs = bio->bi_private; bio_free(bio, bs); } /* * Creates a little bio that is just does part of a bvec. */ static struct bio *split_bvec(struct bio *bio, sector_t sector, unsigned short idx, unsigned int offset, unsigned int len, struct bio_set *bs) { struct bio *clone; struct bio_vec *bv = bio->bi_io_vec + idx; clone = bio_alloc_bioset(GFP_NOIO, 1, bs); clone->bi_destructor = dm_bio_destructor; *clone->bi_io_vec = *bv; clone->bi_sector = sector; clone->bi_bdev = bio->bi_bdev; clone->bi_rw = bio->bi_rw; clone->bi_vcnt = 1; clone->bi_size = to_bytes(len); clone->bi_io_vec->bv_offset = offset; clone->bi_io_vec->bv_len = clone->bi_size; return clone; } /* * Creates a bio that consists of range of complete bvecs. */ static struct bio *clone_bio(struct bio *bio, sector_t sector, unsigned short idx, unsigned short bv_count, unsigned int len, struct bio_set *bs) { struct bio *clone; clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs); __bio_clone(clone, bio); clone->bi_destructor = dm_bio_destructor; clone->bi_sector = sector; clone->bi_idx = idx; clone->bi_vcnt = idx + bv_count; clone->bi_size = to_bytes(len); clone->bi_flags &= ~(1 << BIO_SEG_VALID); return clone; } static void __clone_and_map(struct clone_info *ci) { struct bio *clone, *bio = ci->bio; struct dm_target *ti = dm_table_find_target(ci->map, ci->sector); sector_t len = 0, max = max_io_len(ci->md, ci->sector, ti); struct dm_target_io *tio; /* * Allocate a target io object. */ tio = alloc_tio(ci->md); tio->io = ci->io; tio->ti = ti; memset(&tio->info, 0, sizeof(tio->info)); if (ci->sector_count <= max) { /* * Optimise for the simple case where we can do all of * the remaining io with a single clone. */ clone = clone_bio(bio, ci->sector, ci->idx, bio->bi_vcnt - ci->idx, ci->sector_count, ci->md->bs); __map_bio(ti, clone, tio); ci->sector_count = 0; } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { /* * There are some bvecs that don't span targets. * Do as many of these as possible. */ int i; sector_t remaining = max; sector_t bv_len; for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) { bv_len = to_sector(bio->bi_io_vec[i].bv_len); if (bv_len > remaining) break; remaining -= bv_len; len += bv_len; } clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len, ci->md->bs); __map_bio(ti, clone, tio); ci->sector += len; ci->sector_count -= len; ci->idx = i; } else { /* * Handle a bvec that must be split between two or more targets. */ struct bio_vec *bv = bio->bi_io_vec + ci->idx; sector_t remaining = to_sector(bv->bv_len); unsigned int offset = 0; do { if (offset) { ti = dm_table_find_target(ci->map, ci->sector); max = max_io_len(ci->md, ci->sector, ti); tio = alloc_tio(ci->md); tio->io = ci->io; tio->ti = ti; memset(&tio->info, 0, sizeof(tio->info)); } len = min(remaining, max); clone = split_bvec(bio, ci->sector, ci->idx, bv->bv_offset + offset, len, ci->md->bs); __map_bio(ti, clone, tio); ci->sector += len; ci->sector_count -= len; offset += to_bytes(len); } while (remaining -= len); ci->idx++; } } /* * Split the bio into several clones. */ static void __split_bio(struct mapped_device *md, struct bio *bio) { struct clone_info ci; ci.map = dm_get_table(md); if (!ci.map) { bio_io_error(bio, bio->bi_size); return; } ci.md = md; ci.bio = bio; ci.io = alloc_io(md); ci.io->error = 0; atomic_set(&ci.io->io_count, 1); ci.io->bio = bio; ci.io->md = md; ci.sector = bio->bi_sector; ci.sector_count = bio_sectors(bio); ci.idx = bio->bi_idx; start_io_acct(ci.io); while (ci.sector_count) __clone_and_map(&ci); /* drop the extra reference count */ dec_pending(ci.io, 0); dm_table_put(ci.map); } /*----------------------------------------------------------------- * CRUD END *---------------------------------------------------------------*/ /* * The request function that just remaps the bio built up by * dm_merge_bvec. */ static int dm_request(struct request_queue *q, struct bio *bio) { int r; int rw = bio_data_dir(bio); struct mapped_device *md = q->queuedata; /* * There is no use in forwarding any barrier request since we can't * guarantee it is (or can be) handled by the targets correctly. */ if (unlikely(bio_barrier(bio))) { bio_endio(bio, bio->bi_size, -EOPNOTSUPP); return 0; } down_read(&md->io_lock); disk_stat_inc(dm_disk(md), ios[rw]); disk_stat_add(dm_disk(md), sectors[rw], bio_sectors(bio)); /* * If we're suspended we have to queue * this io for later. */ while (test_bit(DMF_BLOCK_IO, &md->flags)) { up_read(&md->io_lock); if (bio_rw(bio) == READA) { bio_io_error(bio, bio->bi_size); return 0; } r = queue_io(md, bio); if (r < 0) { bio_io_error(bio, bio->bi_size); return 0; } else if (r == 0) return 0; /* deferred successfully */ /* * We're in a while loop, because someone could suspend * before we get to the following read lock. */ down_read(&md->io_lock); } __split_bio(md, bio); up_read(&md->io_lock); return 0; } static int dm_flush_all(struct request_queue *q, struct gendisk *disk, sector_t *error_sector) { struct mapped_device *md = q->queuedata; struct dm_table *map = dm_get_table(md); int ret = -ENXIO; if (map) { ret = dm_table_flush_all(map); dm_table_put(map); } return ret; } static void dm_unplug_all(struct request_queue *q) { struct mapped_device *md = q->queuedata; struct dm_table *map = dm_get_table(md); if (map) { dm_table_unplug_all(map); dm_table_put(map); } } static int dm_any_congested(void *congested_data, int bdi_bits) { int r; struct mapped_device *md = (struct mapped_device *) congested_data; struct dm_table *map = dm_get_table(md); if (!map || test_bit(DMF_BLOCK_IO, &md->flags)) r = bdi_bits; else r = dm_table_any_congested(map, bdi_bits); dm_table_put(map); return r; } /*----------------------------------------------------------------- * An IDR is used to keep track of allocated minor numbers. *---------------------------------------------------------------*/ static DEFINE_IDR(_minor_idr); static void free_minor(int minor) { spin_lock(&_minor_lock); idr_remove(&_minor_idr, minor); spin_unlock(&_minor_lock); } /* * See if the device with a specific minor # is free. */ static int specific_minor(struct mapped_device *md, int minor) { int r, m; if (minor >= (1 << MINORBITS)) return -EINVAL; r = idr_pre_get(&_minor_idr, GFP_KERNEL); if (!r) return -ENOMEM; spin_lock(&_minor_lock); if (idr_find(&_minor_idr, minor)) { r = -EBUSY; goto out; } r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m); if (r) goto out; if (m != minor) { idr_remove(&_minor_idr, m); r = -EBUSY; goto out; } out: spin_unlock(&_minor_lock); return r; } static int next_free_minor(struct mapped_device *md, int *minor) { int r, m; r = idr_pre_get(&_minor_idr, GFP_KERNEL); if (!r) return -ENOMEM; spin_lock(&_minor_lock); r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m); if (r) { goto out; } if (m >= (1 << MINORBITS)) { idr_remove(&_minor_idr, m); r = -ENOSPC; goto out; } *minor = m; out: spin_unlock(&_minor_lock); return r; } static struct block_device_operations dm_blk_dops; /* * Allocate and initialise a blank device with a given minor. */ static struct mapped_device *alloc_dev(int minor) { int r; struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL); void *old_md; if (!md) { DMWARN("unable to allocate device, out of memory."); return NULL; } if (!try_module_get(THIS_MODULE)) goto bad0; /* get a minor number for the dev */ if (minor == DM_ANY_MINOR) r = next_free_minor(md, &minor); else r = specific_minor(md, minor); if (r < 0) goto bad1; memset(md, 0, sizeof(*md)); init_rwsem(&md->io_lock); init_MUTEX(&md->suspend_lock); spin_lock_init(&md->pushback_lock); rwlock_init(&md->map_lock); atomic_set(&md->holders, 1); atomic_set(&md->open_count, 0); atomic_set(&md->event_nr, 0); md->queue = blk_alloc_queue(GFP_KERNEL); if (!md->queue) goto bad1_free_minor; md->queue->queuedata = md; md->queue->backing_dev_info.congested_fn = dm_any_congested; md->queue->backing_dev_info.congested_data = md; blk_queue_make_request(md->queue, dm_request); blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); md->queue->unplug_fn = dm_unplug_all; md->queue->issue_flush_fn = dm_flush_all; md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache); if (!md->io_pool) goto bad2; md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache); if (!md->tio_pool) goto bad3; md->bs = bioset_create(16, 16); if (!md->bs) goto bad_no_bioset; md->disk = alloc_disk(1); if (!md->disk) goto bad4; atomic_set(&md->pending, 0); init_waitqueue_head(&md->wait); init_waitqueue_head(&md->eventq); md->disk->major = _major; md->disk->first_minor = minor; md->disk->fops = &dm_blk_dops; md->disk->queue = md->queue; md->disk->private_data = md; sprintf(md->disk->disk_name, "dm-%d", minor); add_disk(md->disk); format_dev_t(md->name, MKDEV(_major, minor)); /* Populate the mapping, nobody knows we exist yet */ spin_lock(&_minor_lock); old_md = idr_replace(&_minor_idr, md, minor); spin_unlock(&_minor_lock); BUG_ON(old_md != MINOR_ALLOCED); return md; bad4: bioset_free(md->bs); bad_no_bioset: mempool_destroy(md->tio_pool); bad3: mempool_destroy(md->io_pool); bad2: blk_cleanup_queue(md->queue); bad1_free_minor: free_minor(minor); bad1: module_put(THIS_MODULE); bad0: kfree(md); return NULL; } static void free_dev(struct mapped_device *md) { int minor = md->disk->first_minor; if (md->suspended_bdev) { thaw_bdev(md->suspended_bdev, NULL); bdput(md->suspended_bdev); } mempool_destroy(md->tio_pool); mempool_destroy(md->io_pool); bioset_free(md->bs); del_gendisk(md->disk); free_minor(minor); spin_lock(&_minor_lock); md->disk->private_data = NULL; spin_unlock(&_minor_lock); put_disk(md->disk); blk_cleanup_queue(md->queue); module_put(THIS_MODULE); kfree(md); } /* * Bind a table to the device. */ static void event_callback(void *context) { struct mapped_device *md = (struct mapped_device *) context; atomic_inc(&md->event_nr); wake_up(&md->eventq); } static void __set_size(struct mapped_device *md, sector_t size) { set_capacity(md->disk, size); mutex_lock(&md->suspended_bdev->bd_inode->i_mutex); i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT); mutex_unlock(&md->suspended_bdev->bd_inode->i_mutex); } static int __bind(struct mapped_device *md, struct dm_table *t) { struct request_queue *q = md->queue; sector_t size; size = dm_table_get_size(t); /* * Wipe any geometry if the size of the table changed. */ if (size != get_capacity(md->disk)) memset(&md->geometry, 0, sizeof(md->geometry)); if (md->suspended_bdev) __set_size(md, size); if (size == 0) return 0; dm_table_get(t); dm_table_event_callback(t, event_callback, md); write_lock(&md->map_lock); md->map = t; dm_table_set_restrictions(t, q); write_unlock(&md->map_lock); return 0; } static void __unbind(struct mapped_device *md) { struct dm_table *map = md->map; if (!map) return; dm_table_event_callback(map, NULL, NULL); write_lock(&md->map_lock); md->map = NULL; write_unlock(&md->map_lock); dm_table_put(map); } /* * Constructor for a new device. */ int dm_create(int minor, struct mapped_device **result) { struct mapped_device *md; md = alloc_dev(minor); if (!md) return -ENXIO; *result = md; return 0; } static struct mapped_device *dm_find_md(dev_t dev) { struct mapped_device *md; unsigned minor = MINOR(dev); if (MAJOR(dev) != _major || minor >= (1 << MINORBITS)) return NULL; spin_lock(&_minor_lock); md = idr_find(&_minor_idr, minor); if (md && (md == MINOR_ALLOCED || (dm_disk(md)->first_minor != minor) || test_bit(DMF_FREEING, &md->flags))) { md = NULL; goto out; } out: spin_unlock(&_minor_lock); return md; } struct mapped_device *dm_get_md(dev_t dev) { struct mapped_device *md = dm_find_md(dev); if (md) dm_get(md); return md; } void *dm_get_mdptr(struct mapped_device *md) { return md->interface_ptr; } void dm_set_mdptr(struct mapped_device *md, void *ptr) { md->interface_ptr = ptr; } void dm_get(struct mapped_device *md) { atomic_inc(&md->holders); } const char *dm_device_name(struct mapped_device *md) { return md->name; } EXPORT_SYMBOL_GPL(dm_device_name); void dm_put(struct mapped_device *md) { struct dm_table *map; BUG_ON(test_bit(DMF_FREEING, &md->flags)); if (atomic_dec_and_lock(&md->holders, &_minor_lock)) { map = dm_get_table(md); idr_replace(&_minor_idr, MINOR_ALLOCED, dm_disk(md)->first_minor); set_bit(DMF_FREEING, &md->flags); spin_unlock(&_minor_lock); if (!dm_suspended(md)) { dm_table_presuspend_targets(map); dm_table_postsuspend_targets(map); } __unbind(md); dm_table_put(map); free_dev(md); } } EXPORT_SYMBOL_GPL(dm_put); /* * Process the deferred bios */ static void __flush_deferred_io(struct mapped_device *md, struct bio *c) { struct bio *n; while (c) { n = c->bi_next; c->bi_next = NULL; __split_bio(md, c); c = n; } } /* * Swap in a new table (destroying old one). */ int dm_swap_table(struct mapped_device *md, struct dm_table *table) { int r = -EINVAL; down(&md->suspend_lock); /* device must be suspended */ if (!dm_suspended(md)) goto out; /* without bdev, the device size cannot be changed */ if (!md->suspended_bdev) if (get_capacity(md->disk) != dm_table_get_size(table)) goto out; __unbind(md); r = __bind(md, table); out: up(&md->suspend_lock); return r; } /* * Functions to lock and unlock any filesystem running on the * device. */ static int lock_fs(struct mapped_device *md) { int r; WARN_ON(md->frozen_sb); md->frozen_sb = freeze_bdev(md->suspended_bdev); if (IS_ERR(md->frozen_sb)) { r = PTR_ERR(md->frozen_sb); md->frozen_sb = NULL; return r; } set_bit(DMF_FROZEN, &md->flags); /* don't bdput right now, we don't want the bdev * to go away while it is locked. */ return 0; } static void unlock_fs(struct mapped_device *md) { if (!test_bit(DMF_FROZEN, &md->flags)) return; thaw_bdev(md->suspended_bdev, md->frozen_sb); md->frozen_sb = NULL; clear_bit(DMF_FROZEN, &md->flags); } /* * We need to be able to change a mapping table under a mounted * filesystem. For example we might want to move some data in * the background. Before the table can be swapped with * dm_bind_table, dm_suspend must be called to flush any in * flight bios and ensure that any further io gets deferred. */ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) { struct dm_table *map = NULL; unsigned long flags; DECLARE_WAITQUEUE(wait, current); struct bio *def; int r = -EINVAL; int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0; int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0; down(&md->suspend_lock); if (dm_suspended(md)) goto out_unlock; map = dm_get_table(md); /* * DMF_NOFLUSH_SUSPENDING must be set before presuspend. * This flag is cleared before dm_suspend returns. */ if (noflush) set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); /* This does not get reverted if there's an error later. */ dm_table_presuspend_targets(map); /* bdget() can stall if the pending I/Os are not flushed */ if (!noflush) { md->suspended_bdev = bdget_disk(md->disk, 0); if (!md->suspended_bdev) { DMWARN("bdget failed in dm_suspend"); r = -ENOMEM; goto flush_and_out; } } /* * Flush I/O to the device. * noflush supersedes do_lockfs, because lock_fs() needs to flush I/Os. */ if (do_lockfs && !noflush) { r = lock_fs(md); if (r) goto out; } /* * First we set the BLOCK_IO flag so no more ios will be mapped. */ down_write(&md->io_lock); set_bit(DMF_BLOCK_IO, &md->flags); add_wait_queue(&md->wait, &wait); up_write(&md->io_lock); /* unplug */ if (map) dm_table_unplug_all(map); /* * Then we wait for the already mapped ios to * complete. */ while (1) { set_current_state(TASK_INTERRUPTIBLE); if (!atomic_read(&md->pending) || signal_pending(current)) break; io_schedule(); } set_current_state(TASK_RUNNING); down_write(&md->io_lock); remove_wait_queue(&md->wait, &wait); if (noflush) { spin_lock_irqsave(&md->pushback_lock, flags); clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); bio_list_merge_head(&md->deferred, &md->pushback); bio_list_init(&md->pushback); spin_unlock_irqrestore(&md->pushback_lock, flags); } /* were we interrupted ? */ r = -EINTR; if (atomic_read(&md->pending)) { clear_bit(DMF_BLOCK_IO, &md->flags); def = bio_list_get(&md->deferred); __flush_deferred_io(md, def); up_write(&md->io_lock); unlock_fs(md); goto out; /* pushback list is already flushed, so skip flush */ } up_write(&md->io_lock); dm_table_postsuspend_targets(map); set_bit(DMF_SUSPENDED, &md->flags); r = 0; flush_and_out: if (r && noflush) { /* * Because there may be already I/Os in the pushback list, * flush them before return. */ down_write(&md->io_lock); spin_lock_irqsave(&md->pushback_lock, flags); clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); bio_list_merge_head(&md->deferred, &md->pushback); bio_list_init(&md->pushback); spin_unlock_irqrestore(&md->pushback_lock, flags); def = bio_list_get(&md->deferred); __flush_deferred_io(md, def); up_write(&md->io_lock); } out: if (r && md->suspended_bdev) { bdput(md->suspended_bdev); md->suspended_bdev = NULL; } dm_table_put(map); out_unlock: up(&md->suspend_lock); return r; } int dm_resume(struct mapped_device *md) { int r = -EINVAL; struct bio *def; struct dm_table *map = NULL; down(&md->suspend_lock); if (!dm_suspended(md)) goto out; map = dm_get_table(md); if (!map || !dm_table_get_size(map)) goto out; r = dm_table_resume_targets(map); if (r) goto out; down_write(&md->io_lock); clear_bit(DMF_BLOCK_IO, &md->flags); def = bio_list_get(&md->deferred); __flush_deferred_io(md, def); up_write(&md->io_lock); unlock_fs(md); if (md->suspended_bdev) { bdput(md->suspended_bdev); md->suspended_bdev = NULL; } clear_bit(DMF_SUSPENDED, &md->flags); dm_table_unplug_all(map); kobject_uevent(&md->disk->kobj, KOBJ_CHANGE); r = 0; out: dm_table_put(map); up(&md->suspend_lock); return r; } /*----------------------------------------------------------------- * Event notification. *---------------------------------------------------------------*/ uint32_t dm_get_event_nr(struct mapped_device *md) { return atomic_read(&md->event_nr); } int dm_wait_event(struct mapped_device *md, int event_nr) { return wait_event_interruptible(md->eventq, (event_nr != atomic_read(&md->event_nr))); } /* * The gendisk is only valid as long as you have a reference * count on 'md'. */ struct gendisk *dm_disk(struct mapped_device *md) { return md->disk; } int dm_suspended(struct mapped_device *md) { return test_bit(DMF_SUSPENDED, &md->flags); } int dm_noflush_suspending(struct dm_target *ti) { struct mapped_device *md = dm_table_get_md(ti->table); int r = __noflush_suspending(md); dm_put(md); return r; } EXPORT_SYMBOL_GPL(dm_noflush_suspending); static struct block_device_operations dm_blk_dops = { .open = dm_blk_open, .release = dm_blk_close, .ioctl = dm_blk_ioctl, .getgeo = dm_blk_getgeo, .owner = THIS_MODULE }; EXPORT_SYMBOL(dm_get_mapinfo); /* * module hooks */ module_init(dm_init); module_exit(dm_exit); module_param(major, uint, 0); MODULE_PARM_DESC(major, "The major number of the device mapper"); MODULE_DESCRIPTION(DM_NAME " driver"); MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); MODULE_LICENSE("GPL");