/* * 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 #include #include #include /* for rq_end_sector() */ #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); static void do_deferred_remove(struct work_struct *w); static DECLARE_WORK(deferred_remove_work, do_deferred_remove); static struct workqueue_struct *deferred_remove_workqueue; /* * 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; struct dm_stats_aux stats_aux; }; /* * 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; struct kthread_work work; int error; union map_info info; struct dm_stats_aux stats_aux; unsigned long duration_jiffies; unsigned n_sectors; }; /* * For request-based dm - the bio clones we allocate are embedded in these * structs. * * We allocate these with bio_alloc_bioset, using the front_pad parameter when * the bioset is created - this means the bio has to come at the end of the * struct. */ struct dm_rq_clone_bio_info { struct bio *orig; struct dm_rq_target_io *tio; struct bio clone; }; #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_DEFERRED_REMOVE 6 #define DMF_SUSPENDED_INTERNALLY 7 /* * A dummy definition to make RCU happy. * struct dm_table should never be dereferenced in this file. */ struct dm_table { int undefined__; }; /* * Work processed by per-device workqueue. */ struct mapped_device { struct srcu_struct io_barrier; struct mutex suspend_lock; atomic_t holders; atomic_t open_count; /* * The current mapping. * Use dm_get_live_table{_fast} or take suspend_lock for * dereference. */ struct dm_table __rcu *map; struct list_head table_devices; struct mutex table_devices_lock; unsigned long flags; struct request_queue *queue; unsigned type; /* Protect queue and type against concurrent access. */ struct mutex type_lock; struct dm_target *immutable_target; 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; /* * io objects are allocated from here. */ mempool_t *io_pool; mempool_t *rq_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; /* kobject and completion */ struct dm_kobject_holder kobj_holder; /* zero-length flush that will be cloned and submitted to targets */ struct bio flush_bio; /* the number of internal suspends */ unsigned internal_suspend_count; struct dm_stats stats; struct kthread_worker kworker; struct task_struct *kworker_task; /* for request-based merge heuristic in dm_request_fn() */ unsigned seq_rq_merge_deadline_usecs; int last_rq_rw; sector_t last_rq_pos; ktime_t last_rq_start_time; /* for blk-mq request-based DM support */ struct blk_mq_tag_set tag_set; bool use_blk_mq; }; #ifdef CONFIG_DM_MQ_DEFAULT static bool use_blk_mq = true; #else static bool use_blk_mq = false; #endif #define DM_MQ_NR_HW_QUEUES 1 #define DM_MQ_QUEUE_DEPTH 2048 static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES; static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH; bool dm_use_blk_mq(struct mapped_device *md) { return md->use_blk_mq; } /* * For mempools pre-allocation at the table loading time. */ struct dm_md_mempools { mempool_t *io_pool; mempool_t *rq_pool; struct bio_set *bs; }; struct table_device { struct list_head list; atomic_t count; struct dm_dev dm_dev; }; #define RESERVED_BIO_BASED_IOS 16 #define RESERVED_REQUEST_BASED_IOS 256 #define RESERVED_MAX_IOS 1024 static struct kmem_cache *_io_cache; static struct kmem_cache *_rq_tio_cache; static struct kmem_cache *_rq_cache; /* * Bio-based DM's mempools' reserved IOs set by the user. */ static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS; /* * Request-based DM's mempools' reserved IOs set by the user. */ static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS; static unsigned __dm_get_module_param(unsigned *module_param, unsigned def, unsigned max) { unsigned param = ACCESS_ONCE(*module_param); unsigned modified_param = 0; if (!param) modified_param = def; else if (param > max) modified_param = max; if (modified_param) { (void)cmpxchg(module_param, param, modified_param); param = modified_param; } return param; } unsigned dm_get_reserved_bio_based_ios(void) { return __dm_get_module_param(&reserved_bio_based_ios, RESERVED_BIO_BASED_IOS, RESERVED_MAX_IOS); } EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios); unsigned dm_get_reserved_rq_based_ios(void) { return __dm_get_module_param(&reserved_rq_based_ios, RESERVED_REQUEST_BASED_IOS, RESERVED_MAX_IOS); } EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios); static unsigned dm_get_blk_mq_nr_hw_queues(void) { return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32); } static unsigned dm_get_blk_mq_queue_depth(void) { return __dm_get_module_param(&dm_mq_queue_depth, DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH); } 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; _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0); if (!_rq_tio_cache) goto out_free_io_cache; _rq_cache = kmem_cache_create("dm_clone_request", sizeof(struct request), __alignof__(struct request), 0, NULL); if (!_rq_cache) goto out_free_rq_tio_cache; r = dm_uevent_init(); if (r) goto out_free_rq_cache; deferred_remove_workqueue = alloc_workqueue("kdmremove", WQ_UNBOUND, 1); if (!deferred_remove_workqueue) { r = -ENOMEM; goto out_uevent_exit; } _major = major; r = register_blkdev(_major, _name); if (r < 0) goto out_free_workqueue; if (!_major) _major = r; return 0; out_free_workqueue: destroy_workqueue(deferred_remove_workqueue); out_uevent_exit: dm_uevent_exit(); out_free_rq_cache: kmem_cache_destroy(_rq_cache); out_free_rq_tio_cache: kmem_cache_destroy(_rq_tio_cache); out_free_io_cache: kmem_cache_destroy(_io_cache); return r; } static void local_exit(void) { flush_scheduled_work(); destroy_workqueue(deferred_remove_workqueue); kmem_cache_destroy(_rq_cache); kmem_cache_destroy(_rq_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, dm_statistics_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, dm_statistics_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_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 void dm_blk_close(struct gendisk *disk, fmode_t mode) { struct mapped_device *md; spin_lock(&_minor_lock); md = disk->private_data; if (WARN_ON(!md)) goto out; if (atomic_dec_and_test(&md->open_count) && (test_bit(DMF_DEFERRED_REMOVE, &md->flags))) queue_work(deferred_remove_workqueue, &deferred_remove_work); dm_put(md); out: spin_unlock(&_minor_lock); } 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, bool mark_deferred, bool only_deferred) { int r = 0; spin_lock(&_minor_lock); if (dm_open_count(md)) { r = -EBUSY; if (mark_deferred) set_bit(DMF_DEFERRED_REMOVE, &md->flags); } else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags)) r = -EEXIST; else set_bit(DMF_DELETING, &md->flags); spin_unlock(&_minor_lock); return r; } int dm_cancel_deferred_remove(struct mapped_device *md) { int r = 0; spin_lock(&_minor_lock); if (test_bit(DMF_DELETING, &md->flags)) r = -EBUSY; else clear_bit(DMF_DEFERRED_REMOVE, &md->flags); spin_unlock(&_minor_lock); return r; } static void do_deferred_remove(struct work_struct *w) { dm_deferred_remove(); } sector_t dm_get_size(struct mapped_device *md) { return get_capacity(md->disk); } struct request_queue *dm_get_md_queue(struct mapped_device *md) { return md->queue; } struct dm_stats *dm_get_stats(struct mapped_device *md) { return &md->stats; } 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_grab_bdev_for_ioctl(struct mapped_device *md, struct block_device **bdev, fmode_t *mode) { struct dm_target *tgt; struct dm_table *map; int srcu_idx, r; retry: r = -ENOTTY; map = dm_get_live_table(md, &srcu_idx); 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 (!tgt->type->prepare_ioctl) goto out; if (dm_suspended_md(md)) { r = -EAGAIN; goto out; } r = tgt->type->prepare_ioctl(tgt, bdev, mode); if (r < 0) goto out; bdgrab(*bdev); dm_put_live_table(md, srcu_idx); return r; out: dm_put_live_table(md, srcu_idx); if (r == -ENOTCONN && !fatal_signal_pending(current)) { msleep(10); goto retry; } return r; } 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; int r; r = dm_grab_bdev_for_ioctl(md, &bdev, &mode); if (r < 0) return r; if (r > 0) { /* * Target determined this ioctl is being issued against * a logical partition of the parent bdev; so extra * validation is needed. */ r = scsi_verify_blk_ioctl(NULL, cmd); if (r) goto out; } r = __blkdev_driver_ioctl(bdev, mode, cmd, arg); out: bdput(bdev); 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) { bio_put(&tio->clone); } static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md, gfp_t gfp_mask) { return mempool_alloc(md->io_pool, gfp_mask); } static void free_rq_tio(struct dm_rq_target_io *tio) { mempool_free(tio, tio->md->io_pool); } static struct request *alloc_clone_request(struct mapped_device *md, gfp_t gfp_mask) { return mempool_alloc(md->rq_pool, gfp_mask); } static void free_clone_request(struct mapped_device *md, struct request *rq) { mempool_free(rq, md->rq_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; struct bio *bio = io->bio; int cpu; int rw = bio_data_dir(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])); if (unlikely(dm_stats_used(&md->stats))) dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector, bio_sectors(bio), false, 0, &io->stats_aux); } 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; int rw = bio_data_dir(bio); generic_end_io_acct(rw, &dm_disk(md)->part0, io->start_time); if (unlikely(dm_stats_used(&md->stats))) dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector, bio_sectors(bio), true, duration, &io->stats_aux); /* * 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_put_live_table() when finished. */ struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx) __acquires(md->io_barrier) { *srcu_idx = srcu_read_lock(&md->io_barrier); return srcu_dereference(md->map, &md->io_barrier); } void dm_put_live_table(struct mapped_device *md, int srcu_idx) __releases(md->io_barrier) { srcu_read_unlock(&md->io_barrier, srcu_idx); } void dm_sync_table(struct mapped_device *md) { synchronize_srcu(&md->io_barrier); synchronize_rcu_expedited(); } /* * A fast alternative to dm_get_live_table/dm_put_live_table. * The caller must not block between these two functions. */ static struct dm_table *dm_get_live_table_fast(struct mapped_device *md) __acquires(RCU) { rcu_read_lock(); return rcu_dereference(md->map); } static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU) { rcu_read_unlock(); } /* * Open a table device so we can use it as a map destination. */ static int open_table_device(struct table_device *td, dev_t dev, struct mapped_device *md) { static char *_claim_ptr = "I belong to device-mapper"; struct block_device *bdev; int r; BUG_ON(td->dm_dev.bdev); bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _claim_ptr); if (IS_ERR(bdev)) return PTR_ERR(bdev); r = bd_link_disk_holder(bdev, dm_disk(md)); if (r) { blkdev_put(bdev, td->dm_dev.mode | FMODE_EXCL); return r; } td->dm_dev.bdev = bdev; return 0; } /* * Close a table device that we've been using. */ static void close_table_device(struct table_device *td, struct mapped_device *md) { if (!td->dm_dev.bdev) return; bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md)); blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL); td->dm_dev.bdev = NULL; } static struct table_device *find_table_device(struct list_head *l, dev_t dev, fmode_t mode) { struct table_device *td; list_for_each_entry(td, l, list) if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode) return td; return NULL; } int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode, struct dm_dev **result) { int r; struct table_device *td; mutex_lock(&md->table_devices_lock); td = find_table_device(&md->table_devices, dev, mode); if (!td) { td = kmalloc(sizeof(*td), GFP_KERNEL); if (!td) { mutex_unlock(&md->table_devices_lock); return -ENOMEM; } td->dm_dev.mode = mode; td->dm_dev.bdev = NULL; if ((r = open_table_device(td, dev, md))) { mutex_unlock(&md->table_devices_lock); kfree(td); return r; } format_dev_t(td->dm_dev.name, dev); atomic_set(&td->count, 0); list_add(&td->list, &md->table_devices); } atomic_inc(&td->count); mutex_unlock(&md->table_devices_lock); *result = &td->dm_dev; return 0; } EXPORT_SYMBOL_GPL(dm_get_table_device); void dm_put_table_device(struct mapped_device *md, struct dm_dev *d) { struct table_device *td = container_of(d, struct table_device, dm_dev); mutex_lock(&md->table_devices_lock); if (atomic_dec_and_test(&td->count)) { close_table_device(td, md); list_del(&td->list); kfree(td); } mutex_unlock(&md->table_devices_lock); } EXPORT_SYMBOL(dm_put_table_device); static void free_table_devices(struct list_head *devices) { struct list_head *tmp, *next; list_for_each_safe(tmp, next, devices) { struct table_device *td = list_entry(tmp, struct table_device, list); DMWARN("dm_destroy: %s still exists with %d references", td->dm_dev.name, atomic_read(&td->count)); kfree(td); } } /* * 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_iter.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->bi_error = io_error; bio_endio(bio); } } } static void disable_write_same(struct mapped_device *md) { struct queue_limits *limits = dm_get_queue_limits(md); /* device doesn't really support WRITE SAME, disable it */ limits->max_write_same_sectors = 0; } static void clone_endio(struct bio *bio) { int error = bio->bi_error; int r = error; struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone); struct dm_io *io = tio->io; struct mapped_device *md = tio->io->md; dm_endio_fn endio = tio->ti->type->end_io; if (endio) { r = endio(tio->ti, bio, error); 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(); } } if (unlikely(r == -EREMOTEIO && (bio->bi_rw & REQ_WRITE_SAME) && !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors)) disable_write_same(md); free_tio(md, tio); dec_pending(io, error); } /* * Partial completion handling for request-based dm */ static void end_clone_bio(struct bio *clone) { struct dm_rq_clone_bio_info *info = container_of(clone, struct dm_rq_clone_bio_info, clone); struct dm_rq_target_io *tio = info->tio; struct bio *bio = info->orig; unsigned int nr_bytes = info->orig->bi_iter.bi_size; int error = clone->bi_error; 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); } static struct dm_rq_target_io *tio_from_request(struct request *rq) { return (rq->q->mq_ops ? blk_mq_rq_to_pdu(rq) : rq->special); } static void rq_end_stats(struct mapped_device *md, struct request *orig) { if (unlikely(dm_stats_used(&md->stats))) { struct dm_rq_target_io *tio = tio_from_request(orig); tio->duration_jiffies = jiffies - tio->duration_jiffies; dm_stats_account_io(&md->stats, orig->cmd_flags, blk_rq_pos(orig), tio->n_sectors, true, tio->duration_jiffies, &tio->stats_aux); } } /* * 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, bool run_queue) { atomic_dec(&md->pending[rw]); /* nudge anyone waiting on suspend queue */ if (!md_in_flight(md)) wake_up(&md->wait); /* * Run this off this callpath, as drivers could invoke end_io while * inside their request_fn (and holding the queue lock). Calling * back into ->request_fn() could deadlock attempting to grab the * queue lock again. */ if (!md->queue->mq_ops && run_queue) blk_run_queue_async(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; struct mapped_device *md = tio->md; blk_rq_unprep_clone(clone); if (md->type == DM_TYPE_MQ_REQUEST_BASED) /* stacked on blk-mq queue(s) */ tio->ti->type->release_clone_rq(clone); else if (!md->queue->mq_ops) /* request_fn queue stacked on request_fn queue(s) */ free_clone_request(md, clone); /* * NOTE: for the blk-mq queue stacked on request_fn queue(s) case: * no need to call free_clone_request() because we leverage blk-mq by * allocating the clone at the end of the blk-mq pdu (see: clone_rq) */ if (!md->queue->mq_ops) free_rq_tio(tio); } /* * Complete the clone and the original request. * Must be called without clone's queue lock held, * see end_clone_request() for more details. */ 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); rq_end_stats(md, rq); if (!rq->q->mq_ops) blk_end_request_all(rq, error); else blk_mq_end_request(rq, error); rq_completed(md, rw, true); } static void dm_unprep_request(struct request *rq) { struct dm_rq_target_io *tio = tio_from_request(rq); struct request *clone = tio->clone; if (!rq->q->mq_ops) { rq->special = NULL; rq->cmd_flags &= ~REQ_DONTPREP; } if (clone) free_rq_clone(clone); else if (!tio->md->queue->mq_ops) free_rq_tio(tio); } /* * Requeue the original request of a clone. */ static void old_requeue_request(struct request *rq) { struct request_queue *q = rq->q; unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); blk_requeue_request(q, rq); blk_run_queue_async(q); spin_unlock_irqrestore(q->queue_lock, flags); } static void dm_requeue_original_request(struct mapped_device *md, struct request *rq) { int rw = rq_data_dir(rq); dm_unprep_request(rq); rq_end_stats(md, rq); if (!rq->q->mq_ops) old_requeue_request(rq); else { blk_mq_requeue_request(rq); blk_mq_kick_requeue_list(rq->q); } rq_completed(md, rw, false); } static void old_stop_queue(struct request_queue *q) { unsigned long flags; if (blk_queue_stopped(q)) return; spin_lock_irqsave(q->queue_lock, flags); blk_stop_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); } static void stop_queue(struct request_queue *q) { if (!q->mq_ops) old_stop_queue(q); else blk_mq_stop_hw_queues(q); } static void old_start_queue(struct request_queue *q) { unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); if (blk_queue_stopped(q)) blk_start_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); } static void start_queue(struct request_queue *q) { if (!q->mq_ops) old_start_queue(q); else blk_mq_start_stopped_hw_queues(q, true); } 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 = NULL; if (tio->ti) { 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 (unlikely(r == -EREMOTEIO && (clone->cmd_flags & REQ_WRITE_SAME) && !clone->q->limits.max_write_same_sectors)) disable_write_same(tio->md); 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_original_request(tio->md, tio->orig); 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 dm_rq_target_io *tio = tio_from_request(rq); struct request *clone = tio->clone; int rw; if (!clone) { rq_end_stats(tio->md, rq); rw = rq_data_dir(rq); if (!rq->q->mq_ops) { blk_end_request_all(rq, tio->error); rq_completed(tio->md, rw, false); free_rq_tio(tio); } else { blk_mq_end_request(rq, tio->error); rq_completed(tio->md, rw, false); } return; } 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 *rq, int error) { struct dm_rq_target_io *tio = tio_from_request(rq); tio->error = error; if (!rq->q->mq_ops) blk_complete_request(rq); else blk_mq_complete_request(rq, error); } /* * 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() or clone_and_map_rq() functions fail. */ static void dm_kill_unmapped_request(struct request *rq, int error) { rq->cmd_flags |= REQ_FAILED; dm_complete_request(rq, error); } /* * Called with the clone's queue lock held (for non-blk-mq) */ static void end_clone_request(struct request *clone, int error) { struct dm_rq_target_io *tio = clone->end_io_data; if (!clone->q->mq_ops) { /* * 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 (REQ_ALLOCED isn't set). */ __blk_put_request(clone->q, clone); } /* * Actual request completion is done in a softirq context which doesn't * hold the clone's 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 clone's queue */ dm_complete_request(tio->orig, 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); /* * A target may call dm_accept_partial_bio only from the map routine. It is * allowed for all bio types except REQ_FLUSH. * * dm_accept_partial_bio informs the dm that the target only wants to process * additional n_sectors sectors of the bio and the rest of the data should be * sent in a next bio. * * A diagram that explains the arithmetics: * +--------------------+---------------+-------+ * | 1 | 2 | 3 | * +--------------------+---------------+-------+ * * <-------------- *tio->len_ptr ---------------> * <------- bi_size -------> * <-- n_sectors --> * * Region 1 was already iterated over with bio_advance or similar function. * (it may be empty if the target doesn't use bio_advance) * Region 2 is the remaining bio size that the target wants to process. * (it may be empty if region 1 is non-empty, although there is no reason * to make it empty) * The target requires that region 3 is to be sent in the next bio. * * If the target wants to receive multiple copies of the bio (via num_*bios, etc), * the partially processed part (the sum of regions 1+2) must be the same for all * copies of the bio. */ void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors) { struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone); unsigned bi_size = bio->bi_iter.bi_size >> SECTOR_SHIFT; BUG_ON(bio->bi_rw & REQ_FLUSH); BUG_ON(bi_size > *tio->len_ptr); BUG_ON(n_sectors > bi_size); *tio->len_ptr -= bi_size - n_sectors; bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT; } EXPORT_SYMBOL_GPL(dm_accept_partial_bio); static void __map_bio(struct dm_target_io *tio) { int r; sector_t sector; struct mapped_device *md; struct bio *clone = &tio->clone; struct dm_target *ti = tio->ti; clone->bi_end_io = clone_endio; /* * 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_iter.bi_sector; r = ti->type->map(ti, clone); 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); free_tio(md, tio); } else if (r != DM_MAPIO_SUBMITTED) { 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; unsigned sector_count; }; static void bio_setup_sector(struct bio *bio, sector_t sector, unsigned len) { bio->bi_iter.bi_sector = sector; bio->bi_iter.bi_size = to_bytes(len); } /* * Creates a bio that consists of range of complete bvecs. */ static void clone_bio(struct dm_target_io *tio, struct bio *bio, sector_t sector, unsigned len) { struct bio *clone = &tio->clone; __bio_clone_fast(clone, bio); if (bio_integrity(bio)) bio_integrity_clone(clone, bio, GFP_NOIO); bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector)); clone->bi_iter.bi_size = to_bytes(len); if (bio_integrity(bio)) bio_integrity_trim(clone, 0, len); } static struct dm_target_io *alloc_tio(struct clone_info *ci, struct dm_target *ti, unsigned target_bio_nr) { struct dm_target_io *tio; struct bio *clone; clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs); tio = container_of(clone, struct dm_target_io, clone); tio->io = ci->io; tio->ti = ti; tio->target_bio_nr = target_bio_nr; return tio; } static void __clone_and_map_simple_bio(struct clone_info *ci, struct dm_target *ti, unsigned target_bio_nr, unsigned *len) { struct dm_target_io *tio = alloc_tio(ci, ti, target_bio_nr); struct bio *clone = &tio->clone; tio->len_ptr = len; __bio_clone_fast(clone, ci->bio); if (len) bio_setup_sector(clone, ci->sector, *len); __map_bio(tio); } static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti, unsigned num_bios, unsigned *len) { unsigned target_bio_nr; for (target_bio_nr = 0; target_bio_nr < num_bios; target_bio_nr++) __clone_and_map_simple_bio(ci, ti, target_bio_nr, len); } static int __send_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++))) __send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL); return 0; } static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti, sector_t sector, unsigned *len) { struct bio *bio = ci->bio; struct dm_target_io *tio; unsigned target_bio_nr; unsigned num_target_bios = 1; /* * Does the target want to receive duplicate copies of the bio? */ if (bio_data_dir(bio) == WRITE && ti->num_write_bios) num_target_bios = ti->num_write_bios(ti, bio); for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) { tio = alloc_tio(ci, ti, target_bio_nr); tio->len_ptr = len; clone_bio(tio, bio, sector, *len); __map_bio(tio); } } typedef unsigned (*get_num_bios_fn)(struct dm_target *ti); static unsigned get_num_discard_bios(struct dm_target *ti) { return ti->num_discard_bios; } static unsigned get_num_write_same_bios(struct dm_target *ti) { return ti->num_write_same_bios; } typedef bool (*is_split_required_fn)(struct dm_target *ti); static bool is_split_required_for_discard(struct dm_target *ti) { return ti->split_discard_bios; } static int __send_changing_extent_only(struct clone_info *ci, get_num_bios_fn get_num_bios, is_split_required_fn is_split_required) { struct dm_target *ti; unsigned len; unsigned num_bios; do { ti = dm_table_find_target(ci->map, ci->sector); if (!dm_target_is_valid(ti)) return -EIO; /* * Even though the device advertised support for this type of * request, that does not mean every target supports it, and * reconfiguration might also have changed that since the * check was performed. */ num_bios = get_num_bios ? get_num_bios(ti) : 0; if (!num_bios) return -EOPNOTSUPP; if (is_split_required && !is_split_required(ti)) len = min((sector_t)ci->sector_count, max_io_len_target_boundary(ci->sector, ti)); else len = min((sector_t)ci->sector_count, max_io_len(ci->sector, ti)); __send_duplicate_bios(ci, ti, num_bios, &len); ci->sector += len; } while (ci->sector_count -= len); return 0; } static int __send_discard(struct clone_info *ci) { return __send_changing_extent_only(ci, get_num_discard_bios, is_split_required_for_discard); } static int __send_write_same(struct clone_info *ci) { return __send_changing_extent_only(ci, get_num_write_same_bios, NULL); } /* * Select the correct strategy for processing a non-flush bio. */ static int __split_and_process_non_flush(struct clone_info *ci) { struct bio *bio = ci->bio; struct dm_target *ti; unsigned len; if (unlikely(bio->bi_rw & REQ_DISCARD)) return __send_discard(ci); else if (unlikely(bio->bi_rw & REQ_WRITE_SAME)) return __send_write_same(ci); ti = dm_table_find_target(ci->map, ci->sector); if (!dm_target_is_valid(ti)) return -EIO; len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count); __clone_and_map_data_bio(ci, ti, ci->sector, &len); ci->sector += len; ci->sector_count -= len; return 0; } /* * Entry point to split a bio into clones and submit them to the targets. */ static void __split_and_process_bio(struct mapped_device *md, struct dm_table *map, struct bio *bio) { struct clone_info ci; int error = 0; if (unlikely(!map)) { bio_io_error(bio); return; } ci.map = map; 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_iter.bi_sector; start_io_acct(ci.io); if (bio->bi_rw & REQ_FLUSH) { ci.bio = &ci.md->flush_bio; ci.sector_count = 0; error = __send_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 = __split_and_process_non_flush(&ci); } /* drop the extra reference count */ dec_pending(ci.io, error); } /*----------------------------------------------------------------- * CRUD END *---------------------------------------------------------------*/ /* * The request function that just remaps the bio built up by * dm_merge_bvec. */ static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio) { int rw = bio_data_dir(bio); struct mapped_device *md = q->queuedata; int srcu_idx; struct dm_table *map; map = dm_get_live_table(md, &srcu_idx); generic_start_io_acct(rw, bio_sectors(bio), &dm_disk(md)->part0); /* if we're suspended, we have to queue this io for later */ if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) { dm_put_live_table(md, srcu_idx); if (bio_rw(bio) != READA) queue_io(md, bio); else bio_io_error(bio); return BLK_QC_T_NONE; } __split_and_process_bio(md, map, bio); dm_put_live_table(md, srcu_idx); return BLK_QC_T_NONE; } int dm_request_based(struct mapped_device *md) { return blk_queue_stackable(md->queue); } static void dm_dispatch_clone_request(struct request *clone, struct request *rq) { int r; if (blk_queue_io_stat(clone->q)) clone->cmd_flags |= REQ_IO_STAT; clone->start_time = jiffies; r = blk_insert_cloned_request(clone->q, clone); if (r) /* must complete clone in terms of original request */ dm_complete_request(rq, r); } static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig, void *data) { struct dm_rq_target_io *tio = data; struct dm_rq_clone_bio_info *info = container_of(bio, struct dm_rq_clone_bio_info, clone); info->orig = bio_orig; info->tio = tio; bio->bi_end_io = end_clone_bio; return 0; } static int setup_clone(struct request *clone, struct request *rq, struct dm_rq_target_io *tio, gfp_t gfp_mask) { int r; r = blk_rq_prep_clone(clone, rq, tio->md->bs, gfp_mask, dm_rq_bio_constructor, tio); if (r) return r; clone->cmd = rq->cmd; clone->cmd_len = rq->cmd_len; clone->sense = rq->sense; clone->end_io = end_clone_request; clone->end_io_data = tio; tio->clone = clone; return 0; } static struct request *clone_rq(struct request *rq, struct mapped_device *md, struct dm_rq_target_io *tio, gfp_t gfp_mask) { /* * Do not allocate a clone if tio->clone was already set * (see: dm_mq_queue_rq). */ bool alloc_clone = !tio->clone; struct request *clone; if (alloc_clone) { clone = alloc_clone_request(md, gfp_mask); if (!clone) return NULL; } else clone = tio->clone; blk_rq_init(NULL, clone); if (setup_clone(clone, rq, tio, gfp_mask)) { /* -ENOMEM */ if (alloc_clone) free_clone_request(md, clone); return NULL; } return clone; } static void map_tio_request(struct kthread_work *work); static void init_tio(struct dm_rq_target_io *tio, struct request *rq, struct mapped_device *md) { tio->md = md; tio->ti = NULL; tio->clone = NULL; tio->orig = rq; tio->error = 0; memset(&tio->info, 0, sizeof(tio->info)); if (md->kworker_task) init_kthread_work(&tio->work, map_tio_request); } static struct dm_rq_target_io *prep_tio(struct request *rq, struct mapped_device *md, gfp_t gfp_mask) { struct dm_rq_target_io *tio; int srcu_idx; struct dm_table *table; tio = alloc_rq_tio(md, gfp_mask); if (!tio) return NULL; init_tio(tio, rq, md); table = dm_get_live_table(md, &srcu_idx); if (!dm_table_mq_request_based(table)) { if (!clone_rq(rq, md, tio, gfp_mask)) { dm_put_live_table(md, srcu_idx); free_rq_tio(tio); return NULL; } } dm_put_live_table(md, srcu_idx); return tio; } /* * 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 dm_rq_target_io *tio; if (unlikely(rq->special)) { DMWARN("Already has something in rq->special."); return BLKPREP_KILL; } tio = prep_tio(rq, md, GFP_ATOMIC); if (!tio) return BLKPREP_DEFER; rq->special = tio; rq->cmd_flags |= REQ_DONTPREP; return BLKPREP_OK; } /* * Returns: * 0 : the request has been processed * DM_MAPIO_REQUEUE : the original request needs to be requeued * < 0 : the request was completed due to failure */ static int map_request(struct dm_rq_target_io *tio, struct request *rq, struct mapped_device *md) { int r; struct dm_target *ti = tio->ti; struct request *clone = NULL; if (tio->clone) { clone = tio->clone; r = ti->type->map_rq(ti, clone, &tio->info); } else { r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone); if (r < 0) { /* The target wants to complete the I/O */ dm_kill_unmapped_request(rq, r); return r; } if (r != DM_MAPIO_REMAPPED) return r; if (setup_clone(clone, rq, tio, GFP_ATOMIC)) { /* -ENOMEM */ ti->type->release_clone_rq(clone); return DM_MAPIO_REQUEUE; } } 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(rq)); dm_dispatch_clone_request(clone, rq); break; case DM_MAPIO_REQUEUE: /* The target wants to requeue the I/O */ dm_requeue_original_request(md, tio->orig); 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(rq, r); return r; } return 0; } static void map_tio_request(struct kthread_work *work) { struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work); struct request *rq = tio->orig; struct mapped_device *md = tio->md; if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) dm_requeue_original_request(md, rq); } static void dm_start_request(struct mapped_device *md, struct request *orig) { if (!orig->q->mq_ops) blk_start_request(orig); else blk_mq_start_request(orig); atomic_inc(&md->pending[rq_data_dir(orig)]); if (md->seq_rq_merge_deadline_usecs) { md->last_rq_pos = rq_end_sector(orig); md->last_rq_rw = rq_data_dir(orig); md->last_rq_start_time = ktime_get(); } if (unlikely(dm_stats_used(&md->stats))) { struct dm_rq_target_io *tio = tio_from_request(orig); tio->duration_jiffies = jiffies; tio->n_sectors = blk_rq_sectors(orig); dm_stats_account_io(&md->stats, orig->cmd_flags, blk_rq_pos(orig), tio->n_sectors, false, 0, &tio->stats_aux); } /* * 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); } #define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000 ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf) { return sprintf(buf, "%u\n", md->seq_rq_merge_deadline_usecs); } ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md, const char *buf, size_t count) { unsigned deadline; if (!dm_request_based(md) || md->use_blk_mq) return count; if (kstrtouint(buf, 10, &deadline)) return -EINVAL; if (deadline > MAX_SEQ_RQ_MERGE_DEADLINE_USECS) deadline = MAX_SEQ_RQ_MERGE_DEADLINE_USECS; md->seq_rq_merge_deadline_usecs = deadline; return count; } static bool dm_request_peeked_before_merge_deadline(struct mapped_device *md) { ktime_t kt_deadline; if (!md->seq_rq_merge_deadline_usecs) return false; kt_deadline = ns_to_ktime((u64)md->seq_rq_merge_deadline_usecs * NSEC_PER_USEC); kt_deadline = ktime_add_safe(md->last_rq_start_time, kt_deadline); return !ktime_after(ktime_get(), kt_deadline); } /* * 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_target *ti = md->immutable_target; struct request *rq; struct dm_rq_target_io *tio; sector_t pos = 0; if (unlikely(!ti)) { int srcu_idx; struct dm_table *map = dm_get_live_table(md, &srcu_idx); ti = dm_table_find_target(map, pos); dm_put_live_table(md, srcu_idx); } /* * 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) return; /* 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); if ((dm_request_peeked_before_merge_deadline(md) && md_in_flight(md) && rq->bio && rq->bio->bi_vcnt == 1 && md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq)) || (ti->type->busy && ti->type->busy(ti))) { blk_delay_queue(q, HZ / 100); return; } dm_start_request(md, rq); tio = tio_from_request(rq); /* Establish tio->ti before queuing work (map_tio_request) */ tio->ti = ti; queue_kthread_work(&md->kworker, &tio->work); BUG_ON(!irqs_disabled()); } } 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)) { if (dm_request_based(md)) { /* * With request-based DM we only need to check the * top-level queue for congestion. */ r = md->queue->backing_dev_info.wb.state & bdi_bits; } else { map = dm_get_live_table_fast(md); if (map) r = dm_table_any_congested(map, bdi_bits); dm_put_live_table_fast(md); } } 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; if (minor >= (1 << MINORBITS)) return -EINVAL; idr_preload(GFP_KERNEL); spin_lock(&_minor_lock); r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT); spin_unlock(&_minor_lock); idr_preload_end(); if (r < 0) return r == -ENOSPC ? -EBUSY : r; return 0; } static int next_free_minor(int *minor) { int r; idr_preload(GFP_KERNEL); spin_lock(&_minor_lock); r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT); spin_unlock(&_minor_lock); idr_preload_end(); if (r < 0) return r; *minor = r; return 0; } 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 may not have 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); /* * Initialize data that will only be used by a non-blk-mq DM queue * - must do so here (in alloc_dev callchain) before queue is used */ md->queue->queuedata = md; md->queue->backing_dev_info.congested_data = md; } static void dm_init_old_md_queue(struct mapped_device *md) { md->use_blk_mq = false; dm_init_md_queue(md); /* * Initialize aspects of queue that aren't relevant for blk-mq */ md->queue->backing_dev_info.congested_fn = dm_any_congested; blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); } static void cleanup_mapped_device(struct mapped_device *md) { if (md->wq) destroy_workqueue(md->wq); if (md->kworker_task) kthread_stop(md->kworker_task); mempool_destroy(md->io_pool); mempool_destroy(md->rq_pool); if (md->bs) bioset_free(md->bs); cleanup_srcu_struct(&md->io_barrier); if (md->disk) { spin_lock(&_minor_lock); md->disk->private_data = NULL; spin_unlock(&_minor_lock); del_gendisk(md->disk); put_disk(md->disk); } if (md->queue) blk_cleanup_queue(md->queue); if (md->bdev) { bdput(md->bdev); md->bdev = NULL; } } /* * 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; r = init_srcu_struct(&md->io_barrier); if (r < 0) goto bad_io_barrier; md->use_blk_mq = use_blk_mq; md->type = DM_TYPE_NONE; mutex_init(&md->suspend_lock); mutex_init(&md->type_lock); mutex_init(&md->table_devices_lock); spin_lock_init(&md->deferred_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); INIT_LIST_HEAD(&md->table_devices); spin_lock_init(&md->uevent_lock); md->queue = blk_alloc_queue(GFP_KERNEL); if (!md->queue) goto bad; dm_init_md_queue(md); md->disk = alloc_disk(1); if (!md->disk) goto bad; 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); init_completion(&md->kobj_holder.completion); md->kworker_task = NULL; 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_MEM_RECLAIM, 0); if (!md->wq) goto bad; md->bdev = bdget_disk(md->disk, 0); if (!md->bdev) goto bad; bio_init(&md->flush_bio); md->flush_bio.bi_bdev = md->bdev; md->flush_bio.bi_rw = WRITE_FLUSH; dm_stats_init(&md->stats); /* 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: cleanup_mapped_device(md); bad_io_barrier: 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); cleanup_mapped_device(md); if (md->use_blk_mq) blk_mq_free_tag_set(&md->tag_set); free_table_devices(&md->table_devices); dm_stats_cleanup(&md->stats); free_minor(minor); module_put(THIS_MODULE); kfree(md); } static void __bind_mempools(struct mapped_device *md, struct dm_table *t) { struct dm_md_mempools *p = dm_table_get_md_mempools(t); if (md->bs) { /* The md already has necessary mempools. */ if (dm_table_get_type(t) == DM_TYPE_BIO_BASED) { /* * Reload bioset because front_pad may have changed * because a different table was loaded. */ bioset_free(md->bs); md->bs = p->bs; p->bs = NULL; } /* * There's no need to reload with request-based dm * because the size of front_pad doesn't change. * Note for future: If you are to reload bioset, * prep-ed requests in the queue may refer * to bio from the old bioset, so you must walk * through the queue to unprep. */ goto out; } BUG_ON(!p || md->io_pool || md->rq_pool || md->bs); md->io_pool = p->io_pool; p->io_pool = NULL; md->rq_pool = p->rq_pool; p->rq_pool = NULL; md->bs = p->bs; p->bs = NULL; out: /* mempool bind completed, no longer 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); } /* * 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; size = dm_table_get_size(t); /* * Wipe any geometry if the size of the table changed. */ if (size != dm_get_size(md)) 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)) { stop_queue(q); /* * Leverage the fact that request-based DM targets are * immutable singletons and establish md->immutable_target * - used to optimize both dm_request_fn and dm_mq_queue_rq */ md->immutable_target = dm_table_get_immutable_target(t); } __bind_mempools(md, t); old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock)); rcu_assign_pointer(md->map, t); md->immutable_target_type = dm_table_get_immutable_target_type(t); dm_table_set_restrictions(t, q, limits); if (old_map) dm_sync_table(md); return old_map; } /* * Returns unbound table for the caller to free. */ static struct dm_table *__unbind(struct mapped_device *md) { struct dm_table *map = rcu_dereference_protected(md->map, 1); if (!map) return NULL; dm_table_event_callback(map, NULL, NULL); RCU_INIT_POINTER(md->map, NULL); dm_sync_table(md); 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) { BUG_ON(!mutex_is_locked(&md->type_lock)); 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; } /* * The queue_limits are only valid as long as you have a reference * count on 'md'. */ struct queue_limits *dm_get_queue_limits(struct mapped_device *md) { BUG_ON(!atomic_read(&md->holders)); return &md->queue->limits; } EXPORT_SYMBOL_GPL(dm_get_queue_limits); static void init_rq_based_worker_thread(struct mapped_device *md) { /* Initialize the request-based DM worker thread */ init_kthread_worker(&md->kworker); md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker, "kdmwork-%s", dm_device_name(md)); } /* * 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; /* Fully initialize the queue */ q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL); if (!q) return -EINVAL; /* disable dm_request_fn's merge heuristic by default */ md->seq_rq_merge_deadline_usecs = 0; md->queue = q; dm_init_old_md_queue(md); blk_queue_softirq_done(md->queue, dm_softirq_done); blk_queue_prep_rq(md->queue, dm_prep_fn); init_rq_based_worker_thread(md); elv_register_queue(md->queue); return 0; } static int dm_mq_init_request(void *data, struct request *rq, unsigned int hctx_idx, unsigned int request_idx, unsigned int numa_node) { struct mapped_device *md = data; struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq); /* * Must initialize md member of tio, otherwise it won't * be available in dm_mq_queue_rq. */ tio->md = md; return 0; } static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd) { struct request *rq = bd->rq; struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq); struct mapped_device *md = tio->md; struct dm_target *ti = md->immutable_target; if (unlikely(!ti)) { int srcu_idx; struct dm_table *map = dm_get_live_table(md, &srcu_idx); ti = dm_table_find_target(map, 0); dm_put_live_table(md, srcu_idx); } if (ti->type->busy && ti->type->busy(ti)) return BLK_MQ_RQ_QUEUE_BUSY; dm_start_request(md, rq); /* Init tio using md established in .init_request */ init_tio(tio, rq, md); /* * Establish tio->ti before queuing work (map_tio_request) * or making direct call to map_request(). */ tio->ti = ti; /* * Both the table and md type cannot change after initial table load */ if (dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) { /* clone request is allocated at the end of the pdu */ tio->clone = (void *)blk_mq_rq_to_pdu(rq) + sizeof(struct dm_rq_target_io); (void) clone_rq(rq, md, tio, GFP_ATOMIC); queue_kthread_work(&md->kworker, &tio->work); } else { /* Direct call is fine since .queue_rq allows allocations */ if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) { /* Undo dm_start_request() before requeuing */ rq_end_stats(md, rq); rq_completed(md, rq_data_dir(rq), false); return BLK_MQ_RQ_QUEUE_BUSY; } } return BLK_MQ_RQ_QUEUE_OK; } static struct blk_mq_ops dm_mq_ops = { .queue_rq = dm_mq_queue_rq, .map_queue = blk_mq_map_queue, .complete = dm_softirq_done, .init_request = dm_mq_init_request, }; static int dm_init_request_based_blk_mq_queue(struct mapped_device *md) { unsigned md_type = dm_get_md_type(md); struct request_queue *q; int err; memset(&md->tag_set, 0, sizeof(md->tag_set)); md->tag_set.ops = &dm_mq_ops; md->tag_set.queue_depth = dm_get_blk_mq_queue_depth(); md->tag_set.numa_node = NUMA_NO_NODE; md->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE; md->tag_set.nr_hw_queues = dm_get_blk_mq_nr_hw_queues(); if (md_type == DM_TYPE_REQUEST_BASED) { /* make the memory for non-blk-mq clone part of the pdu */ md->tag_set.cmd_size = sizeof(struct dm_rq_target_io) + sizeof(struct request); } else md->tag_set.cmd_size = sizeof(struct dm_rq_target_io); md->tag_set.driver_data = md; err = blk_mq_alloc_tag_set(&md->tag_set); if (err) return err; q = blk_mq_init_allocated_queue(&md->tag_set, md->queue); if (IS_ERR(q)) { err = PTR_ERR(q); goto out_tag_set; } md->queue = q; dm_init_md_queue(md); /* backfill 'mq' sysfs registration normally done in blk_register_queue */ blk_mq_register_disk(md->disk); if (md_type == DM_TYPE_REQUEST_BASED) init_rq_based_worker_thread(md); return 0; out_tag_set: blk_mq_free_tag_set(&md->tag_set); return err; } static unsigned filter_md_type(unsigned type, struct mapped_device *md) { if (type == DM_TYPE_BIO_BASED) return type; return !md->use_blk_mq ? DM_TYPE_REQUEST_BASED : DM_TYPE_MQ_REQUEST_BASED; } /* * Setup the DM device's queue based on md's type */ int dm_setup_md_queue(struct mapped_device *md) { int r; unsigned md_type = filter_md_type(dm_get_md_type(md), md); switch (md_type) { case DM_TYPE_REQUEST_BASED: r = dm_init_request_based_queue(md); if (r) { DMWARN("Cannot initialize queue for request-based mapped device"); return r; } break; case DM_TYPE_MQ_REQUEST_BASED: r = dm_init_request_based_blk_mq_queue(md); if (r) { DMWARN("Cannot initialize queue for request-based blk-mq mapped device"); return r; } break; case DM_TYPE_BIO_BASED: dm_init_old_md_queue(md); blk_queue_make_request(md->queue, dm_make_request); /* * DM handles splitting bios as needed. Free the bio_split bioset * since it won't be used (saves 1 process per bio-based DM device). */ bioset_free(md->queue->bio_split); md->queue->bio_split = NULL; break; } return 0; } struct mapped_device *dm_get_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) { if ((md == MINOR_ALLOCED || (MINOR(disk_devt(dm_disk(md))) != minor) || dm_deleting_md(md) || test_bit(DMF_FREEING, &md->flags))) { md = NULL; goto out; } dm_get(md); } out: spin_unlock(&_minor_lock); 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)); } int dm_hold(struct mapped_device *md) { spin_lock(&_minor_lock); if (test_bit(DMF_FREEING, &md->flags)) { spin_unlock(&_minor_lock); return -EBUSY; } dm_get(md); spin_unlock(&_minor_lock); return 0; } EXPORT_SYMBOL_GPL(dm_hold); 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; int srcu_idx; might_sleep(); spin_lock(&_minor_lock); idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md)))); set_bit(DMF_FREEING, &md->flags); spin_unlock(&_minor_lock); if (dm_request_based(md) && md->kworker_task) flush_kthread_worker(&md->kworker); /* * Take suspend_lock so that presuspend and postsuspend methods * do not race with internal suspend. */ mutex_lock(&md->suspend_lock); map = dm_get_live_table(md, &srcu_idx); if (!dm_suspended_md(md)) { dm_table_presuspend_targets(map); dm_table_postsuspend_targets(map); } /* dm_put_live_table must be before msleep, otherwise deadlock is possible */ dm_put_live_table(md, srcu_idx); mutex_unlock(&md->suspend_lock); /* * 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_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; int srcu_idx; struct dm_table *map; map = dm_get_live_table(md, &srcu_idx); 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; if (dm_request_based(md)) generic_make_request(c); else __split_and_process_bio(md, map, c); } dm_put_live_table(md, srcu_idx); } static void dm_queue_flush(struct mapped_device *md) { clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); smp_mb__after_atomic(); 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 *live_map = NULL, *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; /* * If the new table has no data devices, retain the existing limits. * This helps multipath with queue_if_no_path if all paths disappear, * then new I/O is queued based on these limits, and then some paths * reappear. */ if (dm_table_has_no_data_devices(table)) { live_map = dm_get_live_table_fast(md); if (live_map) limits = md->queue->limits; dm_put_live_table_fast(md); } if (!live_map) { 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); } /* * If __dm_suspend returns 0, the device is completely quiescent * now. There is no request-processing activity. All new requests * are being added to md->deferred list. * * Caller must hold md->suspend_lock */ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, unsigned suspend_flags, int interruptible) { bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG; bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG; int r; /* * 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 gets reverted if there's an error later and the targets * provide the .presuspend_undo hook. */ 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) { dm_table_presuspend_undo_targets(map); return r; } } /* * 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). */ set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); if (map) synchronize_srcu(&md->io_barrier); /* * 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); if (md->kworker_task) flush_kthread_worker(&md->kworker); } 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, interruptible); if (noflush) clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); if (map) synchronize_srcu(&md->io_barrier); /* were we interrupted ? */ if (r < 0) { dm_queue_flush(md); if (dm_request_based(md)) start_queue(md->queue); unlock_fs(md); dm_table_presuspend_undo_targets(map); /* pushback list is already flushed, so skip flush */ } return r; } /* * 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; retry: mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING); if (dm_suspended_md(md)) { r = -EINVAL; goto out_unlock; } if (dm_suspended_internally_md(md)) { /* already internally suspended, wait for internal resume */ mutex_unlock(&md->suspend_lock); r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE); if (r) return r; goto retry; } map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock)); r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE); if (r) goto out_unlock; set_bit(DMF_SUSPENDED, &md->flags); dm_table_postsuspend_targets(map); out_unlock: mutex_unlock(&md->suspend_lock); return r; } static int __dm_resume(struct mapped_device *md, struct dm_table *map) { if (map) { int r = dm_table_resume_targets(map); if (r) return r; } 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); return 0; } int dm_resume(struct mapped_device *md) { int r = -EINVAL; struct dm_table *map = NULL; retry: mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING); if (!dm_suspended_md(md)) goto out; if (dm_suspended_internally_md(md)) { /* already internally suspended, wait for internal resume */ mutex_unlock(&md->suspend_lock); r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE); if (r) return r; goto retry; } map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock)); if (!map || !dm_table_get_size(map)) goto out; r = __dm_resume(md, map); if (r) goto out; clear_bit(DMF_SUSPENDED, &md->flags); r = 0; out: mutex_unlock(&md->suspend_lock); return r; } /* * Internal suspend/resume works like userspace-driven suspend. It waits * until all bios finish and prevents issuing new bios to the target drivers. * It may be used only from the kernel. */ static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_flags) { struct dm_table *map = NULL; if (md->internal_suspend_count++) return; /* nested internal suspend */ if (dm_suspended_md(md)) { set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags); return; /* nest suspend */ } map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock)); /* * Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is * supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend * would require changing .presuspend to return an error -- avoid this * until there is a need for more elaborate variants of internal suspend. */ (void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE); set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags); dm_table_postsuspend_targets(map); } static void __dm_internal_resume(struct mapped_device *md) { BUG_ON(!md->internal_suspend_count); if (--md->internal_suspend_count) return; /* resume from nested internal suspend */ if (dm_suspended_md(md)) goto done; /* resume from nested suspend */ /* * NOTE: existing callers don't need to call dm_table_resume_targets * (which may fail -- so best to avoid it for now by passing NULL map) */ (void) __dm_resume(md, NULL); done: clear_bit(DMF_SUSPENDED_INTERNALLY, &md->flags); smp_mb__after_atomic(); wake_up_bit(&md->flags, DMF_SUSPENDED_INTERNALLY); } void dm_internal_suspend_noflush(struct mapped_device *md) { mutex_lock(&md->suspend_lock); __dm_internal_suspend(md, DM_SUSPEND_NOFLUSH_FLAG); mutex_unlock(&md->suspend_lock); } EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush); void dm_internal_resume(struct mapped_device *md) { mutex_lock(&md->suspend_lock); __dm_internal_resume(md); mutex_unlock(&md->suspend_lock); } EXPORT_SYMBOL_GPL(dm_internal_resume); /* * Fast variants of internal suspend/resume hold md->suspend_lock, * which prevents interaction with userspace-driven suspend. */ void dm_internal_suspend_fast(struct mapped_device *md) { mutex_lock(&md->suspend_lock); if (dm_suspended_md(md) || dm_suspended_internally_md(md)) return; set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); synchronize_srcu(&md->io_barrier); flush_workqueue(md->wq); dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL_GPL(dm_internal_suspend_fast); void dm_internal_resume_fast(struct mapped_device *md) { if (dm_suspended_md(md) || dm_suspended_internally_md(md)) goto done; dm_queue_flush(md); done: mutex_unlock(&md->suspend_lock); } EXPORT_SYMBOL_GPL(dm_internal_resume_fast); /*----------------------------------------------------------------- * 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; } EXPORT_SYMBOL_GPL(dm_disk); struct kobject *dm_kobject(struct mapped_device *md) { return &md->kobj_holder.kobj; } struct mapped_device *dm_get_from_kobject(struct kobject *kobj) { struct mapped_device *md; md = container_of(kobj, struct mapped_device, kobj_holder.kobj); 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_internally_md(struct mapped_device *md) { return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags); } int dm_test_deferred_remove_flag(struct mapped_device *md) { return test_bit(DMF_DEFERRED_REMOVE, &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(struct mapped_device *md, unsigned type, unsigned integrity, unsigned per_bio_data_size) { struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL); struct kmem_cache *cachep = NULL; unsigned int pool_size = 0; unsigned int front_pad; if (!pools) return NULL; type = filter_md_type(type, md); switch (type) { case DM_TYPE_BIO_BASED: cachep = _io_cache; pool_size = dm_get_reserved_bio_based_ios(); front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone); break; case DM_TYPE_REQUEST_BASED: cachep = _rq_tio_cache; pool_size = dm_get_reserved_rq_based_ios(); pools->rq_pool = mempool_create_slab_pool(pool_size, _rq_cache); if (!pools->rq_pool) goto out; /* fall through to setup remaining rq-based pools */ case DM_TYPE_MQ_REQUEST_BASED: if (!pool_size) pool_size = dm_get_reserved_rq_based_ios(); front_pad = offsetof(struct dm_rq_clone_bio_info, clone); /* per_bio_data_size is not used. See __bind_mempools(). */ WARN_ON(per_bio_data_size != 0); break; default: BUG(); } if (cachep) { pools->io_pool = mempool_create_slab_pool(pool_size, cachep); if (!pools->io_pool) goto out; } pools->bs = bioset_create_nobvec(pool_size, front_pad); if (!pools->bs) goto out; if (integrity && bioset_integrity_create(pools->bs, pool_size)) goto out; return pools; out: dm_free_md_mempools(pools); return NULL; } void dm_free_md_mempools(struct dm_md_mempools *pools) { if (!pools) return; mempool_destroy(pools->io_pool); mempool_destroy(pools->rq_pool); if (pools->bs) bioset_free(pools->bs); kfree(pools); } static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key, u32 flags) { struct mapped_device *md = bdev->bd_disk->private_data; const struct pr_ops *ops; fmode_t mode; int r; r = dm_grab_bdev_for_ioctl(md, &bdev, &mode); if (r < 0) return r; ops = bdev->bd_disk->fops->pr_ops; if (ops && ops->pr_register) r = ops->pr_register(bdev, old_key, new_key, flags); else r = -EOPNOTSUPP; bdput(bdev); return r; } static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type, u32 flags) { struct mapped_device *md = bdev->bd_disk->private_data; const struct pr_ops *ops; fmode_t mode; int r; r = dm_grab_bdev_for_ioctl(md, &bdev, &mode); if (r < 0) return r; ops = bdev->bd_disk->fops->pr_ops; if (ops && ops->pr_reserve) r = ops->pr_reserve(bdev, key, type, flags); else r = -EOPNOTSUPP; bdput(bdev); return r; } static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type) { struct mapped_device *md = bdev->bd_disk->private_data; const struct pr_ops *ops; fmode_t mode; int r; r = dm_grab_bdev_for_ioctl(md, &bdev, &mode); if (r < 0) return r; ops = bdev->bd_disk->fops->pr_ops; if (ops && ops->pr_release) r = ops->pr_release(bdev, key, type); else r = -EOPNOTSUPP; bdput(bdev); return r; } static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key, enum pr_type type, bool abort) { struct mapped_device *md = bdev->bd_disk->private_data; const struct pr_ops *ops; fmode_t mode; int r; r = dm_grab_bdev_for_ioctl(md, &bdev, &mode); if (r < 0) return r; ops = bdev->bd_disk->fops->pr_ops; if (ops && ops->pr_preempt) r = ops->pr_preempt(bdev, old_key, new_key, type, abort); else r = -EOPNOTSUPP; bdput(bdev); return r; } static int dm_pr_clear(struct block_device *bdev, u64 key) { struct mapped_device *md = bdev->bd_disk->private_data; const struct pr_ops *ops; fmode_t mode; int r; r = dm_grab_bdev_for_ioctl(md, &bdev, &mode); if (r < 0) return r; ops = bdev->bd_disk->fops->pr_ops; if (ops && ops->pr_clear) r = ops->pr_clear(bdev, key); else r = -EOPNOTSUPP; bdput(bdev); return r; } static const struct pr_ops dm_pr_ops = { .pr_register = dm_pr_register, .pr_reserve = dm_pr_reserve, .pr_release = dm_pr_release, .pr_preempt = dm_pr_preempt, .pr_clear = dm_pr_clear, }; 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, .pr_ops = &dm_pr_ops, .owner = THIS_MODULE }; /* * 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_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools"); module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools"); module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices"); module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices"); module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices"); MODULE_DESCRIPTION(DM_NAME " driver"); MODULE_AUTHOR("Joe Thornber "); MODULE_LICENSE("GPL");