/* * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. */ #include "dm.h" #include "dm-uevent.h" #include #include #include #include #include #include #include #include #include #include #include #include #define DM_MSG_PREFIX "core" #ifdef CONFIG_PRINTK /* * ratelimit state to be used in DMXXX_LIMIT(). */ DEFINE_RATELIMIT_STATE(dm_ratelimit_state, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); EXPORT_SYMBOL(dm_ratelimit_state); #endif /* * Cookies are numeric values sent with CHANGE and REMOVE * uevents while resuming, removing or renaming the device. */ #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE" #define DM_COOKIE_LENGTH 24 static const char *_name = DM_NAME; static unsigned int major = 0; static unsigned int _major = 0; static DEFINE_IDR(_minor_idr); static DEFINE_SPINLOCK(_minor_lock); /* * For bio-based dm. * One of these is allocated per bio. */ struct dm_io { struct mapped_device *md; int error; atomic_t io_count; struct bio *bio; unsigned long start_time; spinlock_t endio_lock; }; /* * For bio-based dm. * 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; }; /* * For request-based dm. * One of these is allocated per request. */ struct dm_rq_target_io { struct mapped_device *md; struct dm_target *ti; struct request *orig, clone; int error; union map_info info; }; /* * For request-based dm. * One of these is allocated per bio. */ struct dm_rq_clone_bio_info { struct bio *orig; struct dm_rq_target_io *tio; }; 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; } union map_info *dm_get_rq_mapinfo(struct request *rq) { if (rq && rq->end_io_data) return &((struct dm_rq_target_io *)rq->end_io_data)->info; return NULL; } EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo); #define MINOR_ALLOCED ((void *)-1) /* * Bits for the md->flags field. */ #define DMF_BLOCK_IO_FOR_SUSPEND 0 #define DMF_SUSPENDED 1 #define DMF_FROZEN 2 #define DMF_FREEING 3 #define DMF_DELETING 4 #define DMF_NOFLUSH_SUSPENDING 5 #define DMF_MERGE_IS_OPTIONAL 6 /* * Work processed by per-device workqueue. */ struct mapped_device { struct rw_semaphore io_lock; struct mutex suspend_lock; rwlock_t map_lock; atomic_t holders; atomic_t open_count; unsigned long flags; struct request_queue *queue; unsigned type; /* Protect queue and type against concurrent access. */ struct mutex type_lock; struct target_type *immutable_target_type; struct gendisk *disk; char name[16]; void *interface_ptr; /* * A list of ios that arrived while we were suspended. */ atomic_t pending[2]; wait_queue_head_t wait; struct work_struct work; struct bio_list deferred; spinlock_t deferred_lock; /* * Processing queue (flush) */ struct workqueue_struct *wq; /* * 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; atomic_t uevent_seq; struct list_head uevent_list; spinlock_t uevent_lock; /* Protect access to uevent_list */ /* * freeze/thaw support require holding onto a super block */ struct super_block *frozen_sb; struct block_device *bdev; /* forced geometry settings */ struct hd_geometry geometry; /* sysfs handle */ struct kobject kobj; /* zero-length flush that will be cloned and submitted to targets */ struct bio flush_bio; }; /* * For mempools pre-allocation at the table loading time. */ struct dm_md_mempools { mempool_t *io_pool; mempool_t *tio_pool; struct bio_set *bs; }; #define MIN_IOS 256 static struct kmem_cache *_io_cache; static struct kmem_cache *_tio_cache; static struct kmem_cache *_rq_tio_cache; static struct kmem_cache *_rq_bio_info_cache; static int __init local_init(void) { int r = -ENOMEM; /* allocate a slab for the dm_ios */ _io_cache = KMEM_CACHE(dm_io, 0); if (!_io_cache) return r; /* allocate a slab for the target ios */ _tio_cache = KMEM_CACHE(dm_target_io, 0); if (!_tio_cache) goto out_free_io_cache; _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0); if (!_rq_tio_cache) goto out_free_tio_cache; _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0); if (!_rq_bio_info_cache) goto out_free_rq_tio_cache; r = dm_uevent_init(); if (r) goto out_free_rq_bio_info_cache; _major = major; r = register_blkdev(_major, _name); if (r < 0) goto out_uevent_exit; if (!_major) _major = r; return 0; out_uevent_exit: dm_uevent_exit(); out_free_rq_bio_info_cache: kmem_cache_destroy(_rq_bio_info_cache); out_free_rq_tio_cache: kmem_cache_destroy(_rq_tio_cache); out_free_tio_cache: kmem_cache_destroy(_tio_cache); out_free_io_cache: kmem_cache_destroy(_io_cache); return r; } static void local_exit(void) { kmem_cache_destroy(_rq_bio_info_cache); kmem_cache_destroy(_rq_tio_cache); kmem_cache_destroy(_tio_cache); kmem_cache_destroy(_io_cache); unregister_blkdev(_major, _name); dm_uevent_exit(); _major = 0; DMINFO("cleaned up"); } static int (*_inits[])(void) __initdata = { local_init, dm_target_init, dm_linear_init, dm_stripe_init, dm_io_init, dm_kcopyd_init, dm_interface_init, }; static void (*_exits[])(void) = { local_exit, dm_target_exit, dm_linear_exit, dm_stripe_exit, dm_io_exit, dm_kcopyd_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](); /* * Should be empty by this point. */ idr_remove_all(&_minor_idr); idr_destroy(&_minor_idr); } /* * Block device functions */ int dm_deleting_md(struct mapped_device *md) { return test_bit(DMF_DELETING, &md->flags); } static int dm_blk_open(struct block_device *bdev, fmode_t mode) { struct mapped_device *md; spin_lock(&_minor_lock); md = bdev->bd_disk->private_data; if (!md) goto out; if (test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) { 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 gendisk *disk, fmode_t mode) { struct mapped_device *md = disk->private_data; spin_lock(&_minor_lock); atomic_dec(&md->open_count); dm_put(md); spin_unlock(&_minor_lock); 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 block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg) { struct mapped_device *md = bdev->bd_disk->private_data; struct dm_table *map = dm_get_live_table(md); struct dm_target *tgt; int r = -ENOTTY; 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(md)) { r = -EAGAIN; goto out; } if (tgt->type->ioctl) r = tgt->type->ioctl(tgt, cmd, arg); out: dm_table_put(map); 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 void free_tio(struct mapped_device *md, struct dm_target_io *tio) { mempool_free(tio, md->tio_pool); } static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md, gfp_t gfp_mask) { return mempool_alloc(md->tio_pool, gfp_mask); } static void free_rq_tio(struct dm_rq_target_io *tio) { mempool_free(tio, tio->md->tio_pool); } static struct dm_rq_clone_bio_info *alloc_bio_info(struct mapped_device *md) { return mempool_alloc(md->io_pool, GFP_ATOMIC); } static void free_bio_info(struct dm_rq_clone_bio_info *info) { mempool_free(info, info->tio->md->io_pool); } static int md_in_flight(struct mapped_device *md) { return atomic_read(&md->pending[READ]) + atomic_read(&md->pending[WRITE]); } static void start_io_acct(struct dm_io *io) { struct mapped_device *md = io->md; int cpu; int rw = bio_data_dir(io->bio); io->start_time = jiffies; cpu = part_stat_lock(); part_round_stats(cpu, &dm_disk(md)->part0); part_stat_unlock(); atomic_set(&dm_disk(md)->part0.in_flight[rw], atomic_inc_return(&md->pending[rw])); } static void 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, cpu; int rw = bio_data_dir(bio); cpu = part_stat_lock(); part_round_stats(cpu, &dm_disk(md)->part0); part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration); part_stat_unlock(); /* * After this is decremented the bio must not be touched if it is * a flush. */ pending = atomic_dec_return(&md->pending[rw]); atomic_set(&dm_disk(md)->part0.in_flight[rw], pending); pending += atomic_read(&md->pending[rw^0x1]); /* nudge anyone waiting on suspend queue */ if (!pending) wake_up(&md->wait); } /* * Add the bio to the list of deferred io. */ static void queue_io(struct mapped_device *md, struct bio *bio) { unsigned long flags; spin_lock_irqsave(&md->deferred_lock, flags); bio_list_add(&md->deferred, bio); spin_unlock_irqrestore(&md->deferred_lock, flags); queue_work(md->wq, &md->work); } /* * 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_live_table(struct mapped_device *md) { struct dm_table *t; unsigned long flags; read_lock_irqsave(&md->map_lock, flags); t = md->map; if (t) dm_table_get(t); read_unlock_irqrestore(&md->map_lock, flags); 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; int io_error; struct bio *bio; struct mapped_device *md = io->md; /* Push-back supersedes any I/O errors */ if (unlikely(error)) { spin_lock_irqsave(&io->endio_lock, flags); if (!(io->error > 0 && __noflush_suspending(md))) io->error = error; spin_unlock_irqrestore(&io->endio_lock, flags); } if (atomic_dec_and_test(&io->io_count)) { if (io->error == DM_ENDIO_REQUEUE) { /* * Target requested pushing back the I/O. */ spin_lock_irqsave(&md->deferred_lock, flags); if (__noflush_suspending(md)) bio_list_add_head(&md->deferred, io->bio); else /* noflush suspend was interrupted. */ io->error = -EIO; spin_unlock_irqrestore(&md->deferred_lock, flags); } io_error = io->error; bio = io->bio; end_io_acct(io); free_io(md, io); if (io_error == DM_ENDIO_REQUEUE) return; if ((bio->bi_rw & REQ_FLUSH) && bio->bi_size) { /* * Preflush done for flush with data, reissue * without REQ_FLUSH. */ bio->bi_rw &= ~REQ_FLUSH; queue_io(md, bio); } else { /* done with normal IO or empty flush */ trace_block_bio_complete(md->queue, bio, io_error); bio_endio(bio, io_error); } } } static void clone_endio(struct bio *bio, int error) { int r = 0; struct dm_target_io *tio = bio->bi_private; struct dm_io *io = tio->io; struct mapped_device *md = tio->io->md; dm_endio_fn endio = tio->ti->type->end_io; 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; else if (r) { DMWARN("unimplemented target endio return value: %d", r); BUG(); } } free_tio(md, tio); bio_put(bio); dec_pending(io, error); } /* * Partial completion handling for request-based dm */ static void end_clone_bio(struct bio *clone, int error) { struct dm_rq_clone_bio_info *info = clone->bi_private; struct dm_rq_target_io *tio = info->tio; struct bio *bio = info->orig; unsigned int nr_bytes = info->orig->bi_size; bio_put(clone); if (tio->error) /* * An error has already been detected on the request. * Once error occurred, just let clone->end_io() handle * the remainder. */ return; else if (error) { /* * Don't notice the error to the upper layer yet. * The error handling decision is made by the target driver, * when the request is completed. */ tio->error = error; return; } /* * I/O for the bio successfully completed. * Notice the data completion to the upper layer. */ /* * bios are processed from the head of the list. * So the completing bio should always be rq->bio. * If it's not, something wrong is happening. */ if (tio->orig->bio != bio) DMERR("bio completion is going in the middle of the request"); /* * Update the original request. * Do not use blk_end_request() here, because it may complete * the original request before the clone, and break the ordering. */ blk_update_request(tio->orig, 0, nr_bytes); } /* * Don't touch any member of the md after calling this function because * the md may be freed in dm_put() at the end of this function. * Or do dm_get() before calling this function and dm_put() later. */ static void rq_completed(struct mapped_device *md, int rw, int run_queue) { atomic_dec(&md->pending[rw]); /* nudge anyone waiting on suspend queue */ if (!md_in_flight(md)) wake_up(&md->wait); if (run_queue) blk_run_queue(md->queue); /* * dm_put() must be at the end of this function. See the comment above */ dm_put(md); } static void free_rq_clone(struct request *clone) { struct dm_rq_target_io *tio = clone->end_io_data; blk_rq_unprep_clone(clone); free_rq_tio(tio); } /* * Complete the clone and the original request. * Must be called without queue lock. */ static void dm_end_request(struct request *clone, int error) { int rw = rq_data_dir(clone); struct dm_rq_target_io *tio = clone->end_io_data; struct mapped_device *md = tio->md; struct request *rq = tio->orig; if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { rq->errors = clone->errors; rq->resid_len = clone->resid_len; if (rq->sense) /* * We are using the sense buffer of the original * request. * So setting the length of the sense data is enough. */ rq->sense_len = clone->sense_len; } free_rq_clone(clone); blk_end_request_all(rq, error); rq_completed(md, rw, true); } static void dm_unprep_request(struct request *rq) { struct request *clone = rq->special; rq->special = NULL; rq->cmd_flags &= ~REQ_DONTPREP; free_rq_clone(clone); } /* * Requeue the original request of a clone. */ void dm_requeue_unmapped_request(struct request *clone) { int rw = rq_data_dir(clone); struct dm_rq_target_io *tio = clone->end_io_data; struct mapped_device *md = tio->md; struct request *rq = tio->orig; struct request_queue *q = rq->q; unsigned long flags; dm_unprep_request(rq); spin_lock_irqsave(q->queue_lock, flags); blk_requeue_request(q, rq); spin_unlock_irqrestore(q->queue_lock, flags); rq_completed(md, rw, 0); } EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request); static void __stop_queue(struct request_queue *q) { blk_stop_queue(q); } static void stop_queue(struct request_queue *q) { unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); __stop_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); } static void __start_queue(struct request_queue *q) { if (blk_queue_stopped(q)) blk_start_queue(q); } static void start_queue(struct request_queue *q) { unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); __start_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); } static void dm_done(struct request *clone, int error, bool mapped) { int r = error; struct dm_rq_target_io *tio = clone->end_io_data; dm_request_endio_fn rq_end_io = tio->ti->type->rq_end_io; if (mapped && rq_end_io) r = rq_end_io(tio->ti, clone, error, &tio->info); if (r <= 0) /* The target wants to complete the I/O */ dm_end_request(clone, r); else if (r == DM_ENDIO_INCOMPLETE) /* The target will handle the I/O */ return; else if (r == DM_ENDIO_REQUEUE) /* The target wants to requeue the I/O */ dm_requeue_unmapped_request(clone); else { DMWARN("unimplemented target endio return value: %d", r); BUG(); } } /* * Request completion handler for request-based dm */ static void dm_softirq_done(struct request *rq) { bool mapped = true; struct request *clone = rq->completion_data; struct dm_rq_target_io *tio = clone->end_io_data; if (rq->cmd_flags & REQ_FAILED) mapped = false; dm_done(clone, tio->error, mapped); } /* * Complete the clone and the original request with the error status * through softirq context. */ static void dm_complete_request(struct request *clone, int error) { struct dm_rq_target_io *tio = clone->end_io_data; struct request *rq = tio->orig; tio->error = error; rq->completion_data = clone; blk_complete_request(rq); } /* * Complete the not-mapped clone and the original request with the error status * through softirq context. * Target's rq_end_io() function isn't called. * This may be used when the target's map_rq() function fails. */ void dm_kill_unmapped_request(struct request *clone, int error) { struct dm_rq_target_io *tio = clone->end_io_data; struct request *rq = tio->orig; rq->cmd_flags |= REQ_FAILED; dm_complete_request(clone, error); } EXPORT_SYMBOL_GPL(dm_kill_unmapped_request); /* * Called with the queue lock held */ static void end_clone_request(struct request *clone, int error) { /* * For just cleaning up the information of the queue in which * the clone was dispatched. * The clone is *NOT* freed actually here because it is alloced from * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags. */ __blk_put_request(clone->q, clone); /* * Actual request completion is done in a softirq context which doesn't * hold the queue lock. Otherwise, deadlock could occur because: * - another request may be submitted by the upper level driver * of the stacking during the completion * - the submission which requires queue lock may be done * against this queue */ dm_complete_request(clone, error); } /* * Return maximum size of I/O possible at the supplied sector up to the current * target boundary. */ static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti) { sector_t target_offset = dm_target_offset(ti, sector); return ti->len - target_offset; } static sector_t max_io_len(sector_t sector, struct dm_target *ti) { sector_t len = max_io_len_target_boundary(sector, ti); sector_t offset, max_len; /* * Does the target need to split even further? */ if (ti->max_io_len) { offset = dm_target_offset(ti, sector); if (unlikely(ti->max_io_len & (ti->max_io_len - 1))) max_len = sector_div(offset, ti->max_io_len); else max_len = offset & (ti->max_io_len - 1); max_len = ti->max_io_len - max_len; if (len > max_len) len = max_len; } return len; } int dm_set_target_max_io_len(struct dm_target *ti, sector_t len) { if (len > UINT_MAX) { DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)", (unsigned long long)len, UINT_MAX); ti->error = "Maximum size of target IO is too large"; return -EINVAL; } ti->max_io_len = (uint32_t) len; return 0; } EXPORT_SYMBOL_GPL(dm_set_target_max_io_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; 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 */ trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone, tio->io->bio->bi_bdev->bd_dev, 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); 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; }; /* * Creates a little bio that 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_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; clone->bi_flags |= 1 << BIO_CLONED; if (bio_integrity(bio)) { bio_integrity_clone(clone, bio, GFP_NOIO, bs); bio_integrity_trim(clone, bio_sector_offset(bio, idx, offset), len); } 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_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); if (bio_integrity(bio)) { bio_integrity_clone(clone, bio, GFP_NOIO, bs); if (idx != bio->bi_idx || clone->bi_size < bio->bi_size) bio_integrity_trim(clone, bio_sector_offset(bio, idx, 0), len); } return clone; } static struct dm_target_io *alloc_tio(struct clone_info *ci, struct dm_target *ti) { struct dm_target_io *tio = mempool_alloc(ci->md->tio_pool, GFP_NOIO); tio->io = ci->io; tio->ti = ti; memset(&tio->info, 0, sizeof(tio->info)); return tio; } static void __issue_target_request(struct clone_info *ci, struct dm_target *ti, unsigned request_nr, sector_t len) { struct dm_target_io *tio = alloc_tio(ci, ti); struct bio *clone; tio->info.target_request_nr = request_nr; /* * Discard requests require the bio's inline iovecs be initialized. * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush * and discard, so no need for concern about wasted bvec allocations. */ clone = bio_alloc_bioset(GFP_NOIO, ci->bio->bi_max_vecs, ci->md->bs); __bio_clone(clone, ci->bio); if (len) { clone->bi_sector = ci->sector; clone->bi_size = to_bytes(len); } __map_bio(ti, clone, tio); } static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti, unsigned num_requests, sector_t len) { unsigned request_nr; for (request_nr = 0; request_nr < num_requests; request_nr++) __issue_target_request(ci, ti, request_nr, len); } static int __clone_and_map_empty_flush(struct clone_info *ci) { unsigned target_nr = 0; struct dm_target *ti; BUG_ON(bio_has_data(ci->bio)); while ((ti = dm_table_get_target(ci->map, target_nr++))) __issue_target_requests(ci, ti, ti->num_flush_requests, 0); return 0; } /* * Perform all io with a single clone. */ static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti) { struct bio *clone, *bio = ci->bio; struct dm_target_io *tio; tio = alloc_tio(ci, ti); 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; } static int __clone_and_map_discard(struct clone_info *ci) { struct dm_target *ti; sector_t len; do { ti = dm_table_find_target(ci->map, ci->sector); if (!dm_target_is_valid(ti)) return -EIO; /* * Even though the device advertised discard support, * that does not mean every target supports it, and * reconfiguration might also have changed that since the * check was performed. */ if (!ti->num_discard_requests) return -EOPNOTSUPP; if (!ti->split_discard_requests) len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti)); else len = min(ci->sector_count, max_io_len(ci->sector, ti)); __issue_target_requests(ci, ti, ti->num_discard_requests, len); ci->sector += len; } while (ci->sector_count -= len); return 0; } static int __clone_and_map(struct clone_info *ci) { struct bio *clone, *bio = ci->bio; struct dm_target *ti; sector_t len = 0, max; struct dm_target_io *tio; if (unlikely(bio->bi_rw & REQ_DISCARD)) return __clone_and_map_discard(ci); ti = dm_table_find_target(ci->map, ci->sector); if (!dm_target_is_valid(ti)) return -EIO; max = max_io_len(ci->sector, ti); if (ci->sector_count <= max) { /* * Optimise for the simple case where we can do all of * the remaining io with a single clone. */ __clone_and_map_simple(ci, ti); } 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; } tio = alloc_tio(ci, ti); 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); if (!dm_target_is_valid(ti)) return -EIO; max = max_io_len(ci->sector, ti); } len = min(remaining, max); tio = alloc_tio(ci, ti); 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++; } return 0; } /* * Split the bio into several clones and submit it to targets. */ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) { struct clone_info ci; int error = 0; ci.map = dm_get_live_table(md); if (unlikely(!ci.map)) { bio_io_error(bio); return; } ci.md = md; ci.io = alloc_io(md); ci.io->error = 0; atomic_set(&ci.io->io_count, 1); ci.io->bio = bio; ci.io->md = md; spin_lock_init(&ci.io->endio_lock); ci.sector = bio->bi_sector; ci.idx = bio->bi_idx; start_io_acct(ci.io); if (bio->bi_rw & REQ_FLUSH) { ci.bio = &ci.md->flush_bio; ci.sector_count = 0; error = __clone_and_map_empty_flush(&ci); /* dec_pending submits any data associated with flush */ } else { ci.bio = bio; ci.sector_count = bio_sectors(bio); while (ci.sector_count && !error) error = __clone_and_map(&ci); } /* drop the extra reference count */ dec_pending(ci.io, error); dm_table_put(ci.map); } /*----------------------------------------------------------------- * CRUD END *---------------------------------------------------------------*/ static int dm_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *biovec) { struct mapped_device *md = q->queuedata; struct dm_table *map = dm_get_live_table(md); struct dm_target *ti; sector_t max_sectors; int max_size = 0; if (unlikely(!map)) goto out; ti = dm_table_find_target(map, bvm->bi_sector); if (!dm_target_is_valid(ti)) goto out_table; /* * Find maximum amount of I/O that won't need splitting */ max_sectors = min(max_io_len(bvm->bi_sector, ti), (sector_t) BIO_MAX_SECTORS); max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size; if (max_size < 0) max_size = 0; /* * merge_bvec_fn() returns number of bytes * it can accept at this offset * max is precomputed maximal io size */ if (max_size && ti->type->merge) max_size = ti->type->merge(ti, bvm, biovec, max_size); /* * If the target doesn't support merge method and some of the devices * provided their merge_bvec method (we know this by looking at * queue_max_hw_sectors), then we can't allow bios with multiple vector * entries. So always set max_size to 0, and the code below allows * just one page. */ else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9) max_size = 0; out_table: dm_table_put(map); out: /* * Always allow an entire first page */ if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT)) max_size = biovec->bv_len; return max_size; } /* * The request function that just remaps the bio built up by * dm_merge_bvec. */ static void _dm_request(struct request_queue *q, struct bio *bio) { int rw = bio_data_dir(bio); struct mapped_device *md = q->queuedata; int cpu; down_read(&md->io_lock); cpu = part_stat_lock(); part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]); part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio)); part_stat_unlock(); /* if we're suspended, we have to queue this io for later */ if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) { up_read(&md->io_lock); if (bio_rw(bio) != READA) queue_io(md, bio); else bio_io_error(bio); return; } __split_and_process_bio(md, bio); up_read(&md->io_lock); return; } static int dm_request_based(struct mapped_device *md) { return blk_queue_stackable(md->queue); } static void dm_request(struct request_queue *q, struct bio *bio) { struct mapped_device *md = q->queuedata; if (dm_request_based(md)) blk_queue_bio(q, bio); else _dm_request(q, bio); } void dm_dispatch_request(struct request *rq) { int r; if (blk_queue_io_stat(rq->q)) rq->cmd_flags |= REQ_IO_STAT; rq->start_time = jiffies; r = blk_insert_cloned_request(rq->q, rq); if (r) dm_complete_request(rq, r); } EXPORT_SYMBOL_GPL(dm_dispatch_request); static void dm_rq_bio_destructor(struct bio *bio) { struct dm_rq_clone_bio_info *info = bio->bi_private; struct mapped_device *md = info->tio->md; free_bio_info(info); bio_free(bio, md->bs); } static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig, void *data) { struct dm_rq_target_io *tio = data; struct mapped_device *md = tio->md; struct dm_rq_clone_bio_info *info = alloc_bio_info(md); if (!info) return -ENOMEM; info->orig = bio_orig; info->tio = tio; bio->bi_end_io = end_clone_bio; bio->bi_private = info; bio->bi_destructor = dm_rq_bio_destructor; return 0; } static int setup_clone(struct request *clone, struct request *rq, struct dm_rq_target_io *tio) { int r; r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC, dm_rq_bio_constructor, tio); if (r) return r; clone->cmd = rq->cmd; clone->cmd_len = rq->cmd_len; clone->sense = rq->sense; clone->buffer = rq->buffer; clone->end_io = end_clone_request; clone->end_io_data = tio; return 0; } static struct request *clone_rq(struct request *rq, struct mapped_device *md, gfp_t gfp_mask) { struct request *clone; struct dm_rq_target_io *tio; tio = alloc_rq_tio(md, gfp_mask); if (!tio) return NULL; tio->md = md; tio->ti = NULL; tio->orig = rq; tio->error = 0; memset(&tio->info, 0, sizeof(tio->info)); clone = &tio->clone; if (setup_clone(clone, rq, tio)) { /* -ENOMEM */ free_rq_tio(tio); return NULL; } return clone; } /* * Called with the queue lock held. */ static int dm_prep_fn(struct request_queue *q, struct request *rq) { struct mapped_device *md = q->queuedata; struct request *clone; if (unlikely(rq->special)) { DMWARN("Already has something in rq->special."); return BLKPREP_KILL; } clone = clone_rq(rq, md, GFP_ATOMIC); if (!clone) return BLKPREP_DEFER; rq->special = clone; rq->cmd_flags |= REQ_DONTPREP; return BLKPREP_OK; } /* * Returns: * 0 : the request has been processed (not requeued) * !0 : the request has been requeued */ static int map_request(struct dm_target *ti, struct request *clone, struct mapped_device *md) { int r, requeued = 0; struct dm_rq_target_io *tio = clone->end_io_data; /* * Hold the md reference here for the in-flight I/O. * We can't rely on the reference count by device opener, * because the device may be closed during the request completion * when all bios are completed. * See the comment in rq_completed() too. */ dm_get(md); tio->ti = ti; r = ti->type->map_rq(ti, clone, &tio->info); switch (r) { case DM_MAPIO_SUBMITTED: /* The target has taken the I/O to submit by itself later */ break; case DM_MAPIO_REMAPPED: /* The target has remapped the I/O so dispatch it */ trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)), blk_rq_pos(tio->orig)); dm_dispatch_request(clone); break; case DM_MAPIO_REQUEUE: /* The target wants to requeue the I/O */ dm_requeue_unmapped_request(clone); requeued = 1; break; default: if (r > 0) { DMWARN("unimplemented target map return value: %d", r); BUG(); } /* The target wants to complete the I/O */ dm_kill_unmapped_request(clone, r); break; } return requeued; } /* * q->request_fn for request-based dm. * Called with the queue lock held. */ static void dm_request_fn(struct request_queue *q) { struct mapped_device *md = q->queuedata; struct dm_table *map = dm_get_live_table(md); struct dm_target *ti; struct request *rq, *clone; sector_t pos; /* * For suspend, check blk_queue_stopped() and increment * ->pending within a single queue_lock not to increment the * number of in-flight I/Os after the queue is stopped in * dm_suspend(). */ while (!blk_queue_stopped(q)) { rq = blk_peek_request(q); if (!rq) goto delay_and_out; /* always use block 0 to find the target for flushes for now */ pos = 0; if (!(rq->cmd_flags & REQ_FLUSH)) pos = blk_rq_pos(rq); ti = dm_table_find_target(map, pos); BUG_ON(!dm_target_is_valid(ti)); if (ti->type->busy && ti->type->busy(ti)) goto delay_and_out; blk_start_request(rq); clone = rq->special; atomic_inc(&md->pending[rq_data_dir(clone)]); spin_unlock(q->queue_lock); if (map_request(ti, clone, md)) goto requeued; BUG_ON(!irqs_disabled()); spin_lock(q->queue_lock); } goto out; requeued: BUG_ON(!irqs_disabled()); spin_lock(q->queue_lock); delay_and_out: blk_delay_queue(q, HZ / 10); out: dm_table_put(map); return; } int dm_underlying_device_busy(struct request_queue *q) { return blk_lld_busy(q); } EXPORT_SYMBOL_GPL(dm_underlying_device_busy); static int dm_lld_busy(struct request_queue *q) { int r; struct mapped_device *md = q->queuedata; struct dm_table *map = dm_get_live_table(md); if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) r = 1; else r = dm_table_any_busy_target(map); dm_table_put(map); return r; } static int dm_any_congested(void *congested_data, int bdi_bits) { int r = bdi_bits; struct mapped_device *md = congested_data; struct dm_table *map; if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { map = dm_get_live_table(md); if (map) { /* * Request-based dm cares about only own queue for * the query about congestion status of request_queue */ if (dm_request_based(md)) r = md->queue->backing_dev_info.state & 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 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(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(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 const struct block_device_operations dm_blk_dops; static void dm_wq_work(struct work_struct *work); static void dm_init_md_queue(struct mapped_device *md) { /* * Request-based dm devices cannot be stacked on top of bio-based dm * devices. The type of this dm device has not been decided yet. * The type is decided at the first table loading time. * To prevent problematic device stacking, clear the queue flag * for request stacking support until then. * * This queue is new, so no concurrency on the queue_flags. */ queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue); 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); blk_queue_merge_bvec(md->queue, dm_merge_bvec); } /* * Allocate and initialise a blank device with a given minor. */ static struct mapped_device *alloc_dev(int minor) { int r; struct mapped_device *md = kzalloc(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 bad_module_get; /* get a minor number for the dev */ if (minor == DM_ANY_MINOR) r = next_free_minor(&minor); else r = specific_minor(minor); if (r < 0) goto bad_minor; md->type = DM_TYPE_NONE; init_rwsem(&md->io_lock); mutex_init(&md->suspend_lock); mutex_init(&md->type_lock); spin_lock_init(&md->deferred_lock); rwlock_init(&md->map_lock); atomic_set(&md->holders, 1); atomic_set(&md->open_count, 0); atomic_set(&md->event_nr, 0); atomic_set(&md->uevent_seq, 0); INIT_LIST_HEAD(&md->uevent_list); spin_lock_init(&md->uevent_lock); md->queue = blk_alloc_queue(GFP_KERNEL); if (!md->queue) goto bad_queue; dm_init_md_queue(md); md->disk = alloc_disk(1); if (!md->disk) goto bad_disk; atomic_set(&md->pending[0], 0); atomic_set(&md->pending[1], 0); init_waitqueue_head(&md->wait); INIT_WORK(&md->work, dm_wq_work); 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)); md->wq = alloc_workqueue("kdmflush", WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0); if (!md->wq) goto bad_thread; md->bdev = bdget_disk(md->disk, 0); if (!md->bdev) goto bad_bdev; bio_init(&md->flush_bio); md->flush_bio.bi_bdev = md->bdev; md->flush_bio.bi_rw = WRITE_FLUSH; /* 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; bad_bdev: destroy_workqueue(md->wq); bad_thread: del_gendisk(md->disk); put_disk(md->disk); bad_disk: blk_cleanup_queue(md->queue); bad_queue: free_minor(minor); bad_minor: module_put(THIS_MODULE); bad_module_get: kfree(md); return NULL; } static void unlock_fs(struct mapped_device *md); static void free_dev(struct mapped_device *md) { int minor = MINOR(disk_devt(md->disk)); unlock_fs(md); bdput(md->bdev); destroy_workqueue(md->wq); if (md->tio_pool) mempool_destroy(md->tio_pool); if (md->io_pool) mempool_destroy(md->io_pool); if (md->bs) bioset_free(md->bs); blk_integrity_unregister(md->disk); 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); } static void __bind_mempools(struct mapped_device *md, struct dm_table *t) { struct dm_md_mempools *p; if (md->io_pool && md->tio_pool && md->bs) /* the md already has necessary mempools */ goto out; p = dm_table_get_md_mempools(t); BUG_ON(!p || md->io_pool || md->tio_pool || md->bs); md->io_pool = p->io_pool; p->io_pool = NULL; md->tio_pool = p->tio_pool; p->tio_pool = NULL; md->bs = p->bs; p->bs = NULL; out: /* mempool bind completed, now no need any mempools in the table */ dm_table_free_md_mempools(t); } /* * Bind a table to the device. */ static void event_callback(void *context) { unsigned long flags; LIST_HEAD(uevents); struct mapped_device *md = (struct mapped_device *) context; spin_lock_irqsave(&md->uevent_lock, flags); list_splice_init(&md->uevent_list, &uevents); spin_unlock_irqrestore(&md->uevent_lock, flags); dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj); atomic_inc(&md->event_nr); wake_up(&md->eventq); } /* * Protected by md->suspend_lock obtained by dm_swap_table(). */ static void __set_size(struct mapped_device *md, sector_t size) { set_capacity(md->disk, size); i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT); } /* * Return 1 if the queue has a compulsory merge_bvec_fn function. * * If this function returns 0, then the device is either a non-dm * device without a merge_bvec_fn, or it is a dm device that is * able to split any bios it receives that are too big. */ int dm_queue_merge_is_compulsory(struct request_queue *q) { struct mapped_device *dev_md; if (!q->merge_bvec_fn) return 0; if (q->make_request_fn == dm_request) { dev_md = q->queuedata; if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags)) return 0; } return 1; } static int dm_device_merge_is_compulsory(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct block_device *bdev = dev->bdev; struct request_queue *q = bdev_get_queue(bdev); return dm_queue_merge_is_compulsory(q); } /* * Return 1 if it is acceptable to ignore merge_bvec_fn based * on the properties of the underlying devices. */ static int dm_table_merge_is_optional(struct dm_table *table) { unsigned i = 0; struct dm_target *ti; while (i < dm_table_get_num_targets(table)) { ti = dm_table_get_target(table, i++); if (ti->type->iterate_devices && ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL)) return 0; } return 1; } /* * Returns old map, which caller must destroy. */ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t, struct queue_limits *limits) { struct dm_table *old_map; struct request_queue *q = md->queue; sector_t size; unsigned long flags; int merge_is_optional; 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)); __set_size(md, size); dm_table_event_callback(t, event_callback, md); /* * The queue hasn't been stopped yet, if the old table type wasn't * for request-based during suspension. So stop it to prevent * I/O mapping before resume. * This must be done before setting the queue restrictions, * because request-based dm may be run just after the setting. */ if (dm_table_request_based(t) && !blk_queue_stopped(q)) stop_queue(q); __bind_mempools(md, t); merge_is_optional = dm_table_merge_is_optional(t); write_lock_irqsave(&md->map_lock, flags); old_map = md->map; md->map = t; md->immutable_target_type = dm_table_get_immutable_target_type(t); dm_table_set_restrictions(t, q, limits); if (merge_is_optional) set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags); else clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags); write_unlock_irqrestore(&md->map_lock, flags); return old_map; } /* * Returns unbound table for the caller to free. */ static struct dm_table *__unbind(struct mapped_device *md) { struct dm_table *map = md->map; unsigned long flags; if (!map) return NULL; dm_table_event_callback(map, NULL, NULL); write_lock_irqsave(&md->map_lock, flags); md->map = NULL; write_unlock_irqrestore(&md->map_lock, flags); return 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; dm_sysfs_init(md); *result = md; return 0; } /* * Functions to manage md->type. * All are required to hold md->type_lock. */ void dm_lock_md_type(struct mapped_device *md) { mutex_lock(&md->type_lock); } void dm_unlock_md_type(struct mapped_device *md) { mutex_unlock(&md->type_lock); } void dm_set_md_type(struct mapped_device *md, unsigned type) { md->type = type; } unsigned dm_get_md_type(struct mapped_device *md) { return md->type; } struct target_type *dm_get_immutable_target_type(struct mapped_device *md) { return md->immutable_target_type; } /* * Fully initialize a request-based queue (->elevator, ->request_fn, etc). */ static int dm_init_request_based_queue(struct mapped_device *md) { struct request_queue *q = NULL; if (md->queue->elevator) return 1; /* Fully initialize the queue */ q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL); if (!q) return 0; md->queue = q; dm_init_md_queue(md); blk_queue_softirq_done(md->queue, dm_softirq_done); blk_queue_prep_rq(md->queue, dm_prep_fn); blk_queue_lld_busy(md->queue, dm_lld_busy); elv_register_queue(md->queue); return 1; } /* * Setup the DM device's queue based on md's type */ int dm_setup_md_queue(struct mapped_device *md) { if ((dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) && !dm_init_request_based_queue(md)) { DMWARN("Cannot initialize queue for request-based mapped device"); return -EINVAL; } 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 || (MINOR(disk_devt(dm_disk(md))) != minor) || dm_deleting_md(md) || 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; } EXPORT_SYMBOL_GPL(dm_get_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); BUG_ON(test_bit(DMF_FREEING, &md->flags)); } const char *dm_device_name(struct mapped_device *md) { return md->name; } EXPORT_SYMBOL_GPL(dm_device_name); static void __dm_destroy(struct mapped_device *md, bool wait) { struct dm_table *map; might_sleep(); spin_lock(&_minor_lock); map = dm_get_live_table(md); idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md)))); set_bit(DMF_FREEING, &md->flags); spin_unlock(&_minor_lock); if (!dm_suspended_md(md)) { dm_table_presuspend_targets(map); dm_table_postsuspend_targets(map); } /* * Rare, but there may be I/O requests still going to complete, * for example. Wait for all references to disappear. * No one should increment the reference count of the mapped_device, * after the mapped_device state becomes DMF_FREEING. */ if (wait) while (atomic_read(&md->holders)) msleep(1); else if (atomic_read(&md->holders)) DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)", dm_device_name(md), atomic_read(&md->holders)); dm_sysfs_exit(md); dm_table_put(map); dm_table_destroy(__unbind(md)); free_dev(md); } void dm_destroy(struct mapped_device *md) { __dm_destroy(md, true); } void dm_destroy_immediate(struct mapped_device *md) { __dm_destroy(md, false); } void dm_put(struct mapped_device *md) { atomic_dec(&md->holders); } EXPORT_SYMBOL_GPL(dm_put); static int dm_wait_for_completion(struct mapped_device *md, int interruptible) { int r = 0; DECLARE_WAITQUEUE(wait, current); add_wait_queue(&md->wait, &wait); while (1) { set_current_state(interruptible); if (!md_in_flight(md)) break; if (interruptible == TASK_INTERRUPTIBLE && signal_pending(current)) { r = -EINTR; break; } io_schedule(); } set_current_state(TASK_RUNNING); remove_wait_queue(&md->wait, &wait); return r; } /* * Process the deferred bios */ static void dm_wq_work(struct work_struct *work) { struct mapped_device *md = container_of(work, struct mapped_device, work); struct bio *c; down_read(&md->io_lock); while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { spin_lock_irq(&md->deferred_lock); c = bio_list_pop(&md->deferred); spin_unlock_irq(&md->deferred_lock); if (!c) break; up_read(&md->io_lock); if (dm_request_based(md)) generic_make_request(c); else __split_and_process_bio(md, c); down_read(&md->io_lock); } up_read(&md->io_lock); } static void dm_queue_flush(struct mapped_device *md) { clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); smp_mb__after_clear_bit(); queue_work(md->wq, &md->work); } /* * Swap in a new table, returning the old one for the caller to destroy. */ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table) { struct dm_table *map = ERR_PTR(-EINVAL); struct queue_limits limits; int r; mutex_lock(&md->suspend_lock); /* device must be suspended */ if (!dm_suspended_md(md)) goto out; r = dm_calculate_queue_limits(table, &limits); if (r) { map = ERR_PTR(r); goto out; } map = __bind(md, table, &limits); out: mutex_unlock(&md->suspend_lock); return map; } /* * 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->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); return 0; } static void unlock_fs(struct mapped_device *md) { if (!test_bit(DMF_FROZEN, &md->flags)) return; thaw_bdev(md->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. */ /* * Suspend mechanism in request-based dm. * * 1. Flush all I/Os by lock_fs() if needed. * 2. Stop dispatching any I/O by stopping the request_queue. * 3. Wait for all in-flight I/Os to be completed or requeued. * * To abort suspend, start the request_queue. */ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) { struct dm_table *map = NULL; int r = 0; int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0; int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0; mutex_lock(&md->suspend_lock); if (dm_suspended_md(md)) { r = -EINVAL; goto out_unlock; } map = dm_get_live_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); /* * Flush I/O to the device. * Any I/O submitted after lock_fs() may not be flushed. * noflush takes precedence over do_lockfs. * (lock_fs() flushes I/Os and waits for them to complete.) */ if (!noflush && do_lockfs) { r = lock_fs(md); if (r) goto out; } /* * Here we must make sure that no processes are submitting requests * to target drivers i.e. no one may be executing * __split_and_process_bio. This is called from dm_request and * dm_wq_work. * * To get all processes out of __split_and_process_bio in dm_request, * we take the write lock. To prevent any process from reentering * __split_and_process_bio from dm_request and quiesce the thread * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call * flush_workqueue(md->wq). */ down_write(&md->io_lock); set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); up_write(&md->io_lock); /* * Stop md->queue before flushing md->wq in case request-based * dm defers requests to md->wq from md->queue. */ if (dm_request_based(md)) stop_queue(md->queue); flush_workqueue(md->wq); /* * At this point no more requests are entering target request routines. * We call dm_wait_for_completion to wait for all existing requests * to finish. */ r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE); down_write(&md->io_lock); if (noflush) clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); up_write(&md->io_lock); /* were we interrupted ? */ if (r < 0) { dm_queue_flush(md); if (dm_request_based(md)) start_queue(md->queue); unlock_fs(md); goto out; /* pushback list is already flushed, so skip flush */ } /* * If dm_wait_for_completion returned 0, the device is completely * quiescent now. There is no request-processing activity. All new * requests are being added to md->deferred list. */ set_bit(DMF_SUSPENDED, &md->flags); dm_table_postsuspend_targets(map); out: dm_table_put(map); out_unlock: mutex_unlock(&md->suspend_lock); return r; } int dm_resume(struct mapped_device *md) { int r = -EINVAL; struct dm_table *map = NULL; mutex_lock(&md->suspend_lock); if (!dm_suspended_md(md)) goto out; map = dm_get_live_table(md); if (!map || !dm_table_get_size(map)) goto out; r = dm_table_resume_targets(map); if (r) goto out; dm_queue_flush(md); /* * Flushing deferred I/Os must be done after targets are resumed * so that mapping of targets can work correctly. * Request-based dm is queueing the deferred I/Os in its request_queue. */ if (dm_request_based(md)) start_queue(md->queue); unlock_fs(md); clear_bit(DMF_SUSPENDED, &md->flags); r = 0; out: dm_table_put(map); mutex_unlock(&md->suspend_lock); return r; } /*----------------------------------------------------------------- * Event notification. *---------------------------------------------------------------*/ int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action, unsigned cookie) { char udev_cookie[DM_COOKIE_LENGTH]; char *envp[] = { udev_cookie, NULL }; if (!cookie) return kobject_uevent(&disk_to_dev(md->disk)->kobj, action); else { snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u", DM_COOKIE_ENV_VAR_NAME, cookie); return kobject_uevent_env(&disk_to_dev(md->disk)->kobj, action, envp); } } uint32_t dm_next_uevent_seq(struct mapped_device *md) { return atomic_add_return(1, &md->uevent_seq); } 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))); } void dm_uevent_add(struct mapped_device *md, struct list_head *elist) { unsigned long flags; spin_lock_irqsave(&md->uevent_lock, flags); list_add(elist, &md->uevent_list); spin_unlock_irqrestore(&md->uevent_lock, flags); } /* * 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; } struct kobject *dm_kobject(struct mapped_device *md) { return &md->kobj; } /* * struct mapped_device should not be exported outside of dm.c * so use this check to verify that kobj is part of md structure */ struct mapped_device *dm_get_from_kobject(struct kobject *kobj) { struct mapped_device *md; md = container_of(kobj, struct mapped_device, kobj); if (&md->kobj != kobj) return NULL; if (test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) return NULL; dm_get(md); return md; } int dm_suspended_md(struct mapped_device *md) { return test_bit(DMF_SUSPENDED, &md->flags); } int dm_suspended(struct dm_target *ti) { return dm_suspended_md(dm_table_get_md(ti->table)); } EXPORT_SYMBOL_GPL(dm_suspended); int dm_noflush_suspending(struct dm_target *ti) { return __noflush_suspending(dm_table_get_md(ti->table)); } EXPORT_SYMBOL_GPL(dm_noflush_suspending); struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity) { struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL); unsigned int pool_size = (type == DM_TYPE_BIO_BASED) ? 16 : MIN_IOS; if (!pools) return NULL; pools->io_pool = (type == DM_TYPE_BIO_BASED) ? mempool_create_slab_pool(MIN_IOS, _io_cache) : mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache); if (!pools->io_pool) goto free_pools_and_out; pools->tio_pool = (type == DM_TYPE_BIO_BASED) ? mempool_create_slab_pool(MIN_IOS, _tio_cache) : mempool_create_slab_pool(MIN_IOS, _rq_tio_cache); if (!pools->tio_pool) goto free_io_pool_and_out; pools->bs = bioset_create(pool_size, 0); if (!pools->bs) goto free_tio_pool_and_out; if (integrity && bioset_integrity_create(pools->bs, pool_size)) goto free_bioset_and_out; return pools; free_bioset_and_out: bioset_free(pools->bs); free_tio_pool_and_out: mempool_destroy(pools->tio_pool); free_io_pool_and_out: mempool_destroy(pools->io_pool); free_pools_and_out: kfree(pools); return NULL; } void dm_free_md_mempools(struct dm_md_mempools *pools) { if (!pools) return; if (pools->io_pool) mempool_destroy(pools->io_pool); if (pools->tio_pool) mempool_destroy(pools->tio_pool); if (pools->bs) bioset_free(pools->bs); kfree(pools); } static const 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 "); MODULE_LICENSE("GPL");