diff options
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 3397 |
1 files changed, 3397 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c new file mode 100644 index 000000000..0ec85d159 --- /dev/null +++ b/drivers/md/dm.c @@ -0,0 +1,3397 @@ +/* + * 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-core.h" +#include "dm-rq.h" +#include "dm-uevent.h" +#include "dm-ima.h" + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/sched/mm.h> +#include <linux/sched/signal.h> +#include <linux/blkpg.h> +#include <linux/bio.h> +#include <linux/mempool.h> +#include <linux/dax.h> +#include <linux/slab.h> +#include <linux/idr.h> +#include <linux/uio.h> +#include <linux/hdreg.h> +#include <linux/delay.h> +#include <linux/wait.h> +#include <linux/pr.h> +#include <linux/refcount.h> +#include <linux/part_stat.h> +#include <linux/blk-crypto.h> +#include <linux/blk-crypto-profile.h> + +#define DM_MSG_PREFIX "core" + +/* + * 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 + +/* + * For REQ_POLLED fs bio, this flag is set if we link mapped underlying + * dm_io into one list, and reuse bio->bi_private as the list head. Before + * ending this fs bio, we will recover its ->bi_private. + */ +#define REQ_DM_POLL_LIST REQ_DRV + +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; + +atomic_t dm_global_event_nr = ATOMIC_INIT(0); +DECLARE_WAIT_QUEUE_HEAD(dm_global_eventq); + +void dm_issue_global_event(void) +{ + atomic_inc(&dm_global_event_nr); + wake_up(&dm_global_eventq); +} + +DEFINE_STATIC_KEY_FALSE(stats_enabled); +DEFINE_STATIC_KEY_FALSE(swap_bios_enabled); +DEFINE_STATIC_KEY_FALSE(zoned_enabled); + +/* + * One of these is allocated (on-stack) per original bio. + */ +struct clone_info { + struct dm_table *map; + struct bio *bio; + struct dm_io *io; + sector_t sector; + unsigned int sector_count; + bool is_abnormal_io:1; + bool submit_as_polled:1; +}; + +static inline struct dm_target_io *clone_to_tio(struct bio *clone) +{ + return container_of(clone, struct dm_target_io, clone); +} + +void *dm_per_bio_data(struct bio *bio, size_t data_size) +{ + if (!dm_tio_flagged(clone_to_tio(bio), DM_TIO_INSIDE_DM_IO)) + return (char *)bio - DM_TARGET_IO_BIO_OFFSET - data_size; + return (char *)bio - DM_IO_BIO_OFFSET - data_size; +} +EXPORT_SYMBOL_GPL(dm_per_bio_data); + +struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size) +{ + struct dm_io *io = (struct dm_io *)((char *)data + data_size); + if (io->magic == DM_IO_MAGIC) + return (struct bio *)((char *)io + DM_IO_BIO_OFFSET); + BUG_ON(io->magic != DM_TIO_MAGIC); + return (struct bio *)((char *)io + DM_TARGET_IO_BIO_OFFSET); +} +EXPORT_SYMBOL_GPL(dm_bio_from_per_bio_data); + +unsigned int dm_bio_get_target_bio_nr(const struct bio *bio) +{ + return container_of(bio, struct dm_target_io, clone)->target_bio_nr; +} +EXPORT_SYMBOL_GPL(dm_bio_get_target_bio_nr); + +#define MINOR_ALLOCED ((void *)-1) + +#define DM_NUMA_NODE NUMA_NO_NODE +static int dm_numa_node = DM_NUMA_NODE; + +#define DEFAULT_SWAP_BIOS (8 * 1048576 / PAGE_SIZE) +static int swap_bios = DEFAULT_SWAP_BIOS; +static int get_swap_bios(void) +{ + int latch = READ_ONCE(swap_bios); + if (unlikely(latch <= 0)) + latch = DEFAULT_SWAP_BIOS; + return latch; +} + +struct table_device { + struct list_head list; + refcount_t count; + struct dm_dev dm_dev; +}; + +/* + * Bio-based DM's mempools' reserved IOs set by the user. + */ +#define RESERVED_BIO_BASED_IOS 16 +static unsigned int reserved_bio_based_ios = RESERVED_BIO_BASED_IOS; + +static int __dm_get_module_param_int(int *module_param, int min, int max) +{ + int param = READ_ONCE(*module_param); + int modified_param = 0; + bool modified = true; + + if (param < min) + modified_param = min; + else if (param > max) + modified_param = max; + else + modified = false; + + if (modified) { + (void)cmpxchg(module_param, param, modified_param); + param = modified_param; + } + + return param; +} + +unsigned int __dm_get_module_param(unsigned int *module_param, unsigned int def, unsigned int max) +{ + unsigned int param = READ_ONCE(*module_param); + unsigned int 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 int dm_get_reserved_bio_based_ios(void) +{ + return __dm_get_module_param(&reserved_bio_based_ios, + RESERVED_BIO_BASED_IOS, DM_RESERVED_MAX_IOS); +} +EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios); + +static unsigned int dm_get_numa_node(void) +{ + return __dm_get_module_param_int(&dm_numa_node, + DM_NUMA_NODE, num_online_nodes() - 1); +} + +static int __init local_init(void) +{ + int r; + + r = dm_uevent_init(); + if (r) + return r; + + 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(); + + return r; +} + +static void local_exit(void) +{ + destroy_workqueue(deferred_remove_workqueue); + + 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; + +#if (IS_ENABLED(CONFIG_IMA) && !IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE)) + DMWARN("CONFIG_IMA_DISABLE_HTABLE is disabled." + " Duplicate IMA measurements will not be recorded in the IMA log."); +#endif + + 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(); +} + +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_prepare_ioctl(struct mapped_device *md, int *srcu_idx, + struct block_device **bdev) +{ + struct dm_target *ti; + struct dm_table *map; + int r; + +retry: + r = -ENOTTY; + map = dm_get_live_table(md, srcu_idx); + if (!map || !dm_table_get_size(map)) + return r; + + /* We only support devices that have a single target */ + if (map->num_targets != 1) + return r; + + ti = dm_table_get_target(map, 0); + if (!ti->type->prepare_ioctl) + return r; + + if (dm_suspended_md(md)) + return -EAGAIN; + + r = ti->type->prepare_ioctl(ti, bdev); + if (r == -ENOTCONN && !fatal_signal_pending(current)) { + dm_put_live_table(md, *srcu_idx); + msleep(10); + goto retry; + } + + return r; +} + +static void dm_unprepare_ioctl(struct mapped_device *md, int srcu_idx) +{ + dm_put_live_table(md, srcu_idx); +} + +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, srcu_idx; + + r = dm_prepare_ioctl(md, &srcu_idx, &bdev); + if (r < 0) + goto out; + + if (r > 0) { + /* + * Target determined this ioctl is being issued against a + * subset of the parent bdev; require extra privileges. + */ + if (!capable(CAP_SYS_RAWIO)) { + DMDEBUG_LIMIT( + "%s: sending ioctl %x to DM device without required privilege.", + current->comm, cmd); + r = -ENOIOCTLCMD; + goto out; + } + } + + if (!bdev->bd_disk->fops->ioctl) + r = -ENOTTY; + else + r = bdev->bd_disk->fops->ioctl(bdev, mode, cmd, arg); +out: + dm_unprepare_ioctl(md, srcu_idx); + return r; +} + +u64 dm_start_time_ns_from_clone(struct bio *bio) +{ + return jiffies_to_nsecs(clone_to_tio(bio)->io->start_time); +} +EXPORT_SYMBOL_GPL(dm_start_time_ns_from_clone); + +static bool bio_is_flush_with_data(struct bio *bio) +{ + return ((bio->bi_opf & REQ_PREFLUSH) && bio->bi_iter.bi_size); +} + +static void dm_io_acct(struct dm_io *io, bool end) +{ + struct dm_stats_aux *stats_aux = &io->stats_aux; + unsigned long start_time = io->start_time; + struct mapped_device *md = io->md; + struct bio *bio = io->orig_bio; + unsigned int sectors; + + /* + * If REQ_PREFLUSH set, don't account payload, it will be + * submitted (and accounted) after this flush completes. + */ + if (bio_is_flush_with_data(bio)) + sectors = 0; + else if (likely(!(dm_io_flagged(io, DM_IO_WAS_SPLIT)))) + sectors = bio_sectors(bio); + else + sectors = io->sectors; + + if (!end) + bdev_start_io_acct(bio->bi_bdev, sectors, bio_op(bio), + start_time); + else + bdev_end_io_acct(bio->bi_bdev, bio_op(bio), start_time); + + if (static_branch_unlikely(&stats_enabled) && + unlikely(dm_stats_used(&md->stats))) { + sector_t sector; + + if (likely(!dm_io_flagged(io, DM_IO_WAS_SPLIT))) + sector = bio->bi_iter.bi_sector; + else + sector = bio_end_sector(bio) - io->sector_offset; + + dm_stats_account_io(&md->stats, bio_data_dir(bio), + sector, sectors, + end, start_time, stats_aux); + } +} + +static void __dm_start_io_acct(struct dm_io *io) +{ + dm_io_acct(io, false); +} + +static void dm_start_io_acct(struct dm_io *io, struct bio *clone) +{ + /* + * Ensure IO accounting is only ever started once. + */ + if (dm_io_flagged(io, DM_IO_ACCOUNTED)) + return; + + /* Expect no possibility for race unless DM_TIO_IS_DUPLICATE_BIO. */ + if (!clone || likely(dm_tio_is_normal(clone_to_tio(clone)))) { + dm_io_set_flag(io, DM_IO_ACCOUNTED); + } else { + unsigned long flags; + /* Can afford locking given DM_TIO_IS_DUPLICATE_BIO */ + spin_lock_irqsave(&io->lock, flags); + if (dm_io_flagged(io, DM_IO_ACCOUNTED)) { + spin_unlock_irqrestore(&io->lock, flags); + return; + } + dm_io_set_flag(io, DM_IO_ACCOUNTED); + spin_unlock_irqrestore(&io->lock, flags); + } + + __dm_start_io_acct(io); +} + +static void dm_end_io_acct(struct dm_io *io) +{ + dm_io_acct(io, true); +} + +static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio) +{ + struct dm_io *io; + struct dm_target_io *tio; + struct bio *clone; + + clone = bio_alloc_clone(NULL, bio, GFP_NOIO, &md->mempools->io_bs); + tio = clone_to_tio(clone); + tio->flags = 0; + dm_tio_set_flag(tio, DM_TIO_INSIDE_DM_IO); + tio->io = NULL; + + io = container_of(tio, struct dm_io, tio); + io->magic = DM_IO_MAGIC; + io->status = BLK_STS_OK; + + /* one ref is for submission, the other is for completion */ + atomic_set(&io->io_count, 2); + this_cpu_inc(*md->pending_io); + io->orig_bio = bio; + io->md = md; + spin_lock_init(&io->lock); + io->start_time = jiffies; + io->flags = 0; + + if (static_branch_unlikely(&stats_enabled)) + dm_stats_record_start(&md->stats, &io->stats_aux); + + return io; +} + +static void free_io(struct dm_io *io) +{ + bio_put(&io->tio.clone); +} + +static struct bio *alloc_tio(struct clone_info *ci, struct dm_target *ti, + unsigned int target_bio_nr, unsigned int *len, gfp_t gfp_mask) +{ + struct mapped_device *md = ci->io->md; + struct dm_target_io *tio; + struct bio *clone; + + if (!ci->io->tio.io) { + /* the dm_target_io embedded in ci->io is available */ + tio = &ci->io->tio; + /* alloc_io() already initialized embedded clone */ + clone = &tio->clone; + } else { + clone = bio_alloc_clone(NULL, ci->bio, gfp_mask, + &md->mempools->bs); + if (!clone) + return NULL; + + /* REQ_DM_POLL_LIST shouldn't be inherited */ + clone->bi_opf &= ~REQ_DM_POLL_LIST; + + tio = clone_to_tio(clone); + tio->flags = 0; /* also clears DM_TIO_INSIDE_DM_IO */ + } + + tio->magic = DM_TIO_MAGIC; + tio->io = ci->io; + tio->ti = ti; + tio->target_bio_nr = target_bio_nr; + tio->len_ptr = len; + tio->old_sector = 0; + + /* Set default bdev, but target must bio_set_dev() before issuing IO */ + clone->bi_bdev = md->disk->part0; + if (unlikely(ti->needs_bio_set_dev)) + bio_set_dev(clone, md->disk->part0); + + if (len) { + clone->bi_iter.bi_size = to_bytes(*len); + if (bio_integrity(clone)) + bio_integrity_trim(clone); + } + + return clone; +} + +static void free_tio(struct bio *clone) +{ + if (dm_tio_flagged(clone_to_tio(clone), DM_TIO_INSIDE_DM_IO)) + return; + bio_put(clone); +} + +/* + * 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(); +} + +static char *_dm_claim_ptr = "I belong to device-mapper"; + +/* + * Open a table device so we can use it as a map destination. + */ +static struct table_device *open_table_device(struct mapped_device *md, + dev_t dev, fmode_t mode) +{ + struct table_device *td; + struct block_device *bdev; + u64 part_off; + int r; + + td = kmalloc_node(sizeof(*td), GFP_KERNEL, md->numa_node_id); + if (!td) + return ERR_PTR(-ENOMEM); + refcount_set(&td->count, 1); + + bdev = blkdev_get_by_dev(dev, mode | FMODE_EXCL, _dm_claim_ptr); + if (IS_ERR(bdev)) { + r = PTR_ERR(bdev); + goto out_free_td; + } + + /* + * We can be called before the dm disk is added. In that case we can't + * register the holder relation here. It will be done once add_disk was + * called. + */ + if (md->disk->slave_dir) { + r = bd_link_disk_holder(bdev, md->disk); + if (r) + goto out_blkdev_put; + } + + td->dm_dev.mode = mode; + td->dm_dev.bdev = bdev; + td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev, &part_off, NULL, NULL); + format_dev_t(td->dm_dev.name, dev); + list_add(&td->list, &md->table_devices); + return td; + +out_blkdev_put: + blkdev_put(bdev, mode | FMODE_EXCL); +out_free_td: + kfree(td); + return ERR_PTR(r); +} + +/* + * Close a table device that we've been using. + */ +static void close_table_device(struct table_device *td, struct mapped_device *md) +{ + if (md->disk->slave_dir) + bd_unlink_disk_holder(td->dm_dev.bdev, md->disk); + blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL); + put_dax(td->dm_dev.dax_dev); + list_del(&td->list); + kfree(td); +} + +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) +{ + struct table_device *td; + + mutex_lock(&md->table_devices_lock); + td = find_table_device(&md->table_devices, dev, mode); + if (!td) { + td = open_table_device(md, dev, mode); + if (IS_ERR(td)) { + mutex_unlock(&md->table_devices_lock); + return PTR_ERR(td); + } + } else { + refcount_inc(&td->count); + } + mutex_unlock(&md->table_devices_lock); + + *result = &td->dm_dev; + return 0; +} + +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 (refcount_dec_and_test(&td->count)) + close_table_device(td, md); + mutex_unlock(&md->table_devices_lock); +} + +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, refcount_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) { + DMERR("Start sector is beyond the geometry limits."); + return -EINVAL; + } + + md->geometry = *geo; + + return 0; +} + +static int __noflush_suspending(struct mapped_device *md) +{ + return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); +} + +static void dm_requeue_add_io(struct dm_io *io, bool first_stage) +{ + struct mapped_device *md = io->md; + + if (first_stage) { + struct dm_io *next = md->requeue_list; + + md->requeue_list = io; + io->next = next; + } else { + bio_list_add_head(&md->deferred, io->orig_bio); + } +} + +static void dm_kick_requeue(struct mapped_device *md, bool first_stage) +{ + if (first_stage) + queue_work(md->wq, &md->requeue_work); + else + queue_work(md->wq, &md->work); +} + +/* + * Return true if the dm_io's original bio is requeued. + * io->status is updated with error if requeue disallowed. + */ +static bool dm_handle_requeue(struct dm_io *io, bool first_stage) +{ + struct bio *bio = io->orig_bio; + bool handle_requeue = (io->status == BLK_STS_DM_REQUEUE); + bool handle_polled_eagain = ((io->status == BLK_STS_AGAIN) && + (bio->bi_opf & REQ_POLLED)); + struct mapped_device *md = io->md; + bool requeued = false; + + if (handle_requeue || handle_polled_eagain) { + unsigned long flags; + + if (bio->bi_opf & REQ_POLLED) { + /* + * Upper layer won't help us poll split bio + * (io->orig_bio may only reflect a subset of the + * pre-split original) so clear REQ_POLLED. + */ + bio_clear_polled(bio); + } + + /* + * Target requested pushing back the I/O or + * polled IO hit BLK_STS_AGAIN. + */ + spin_lock_irqsave(&md->deferred_lock, flags); + if ((__noflush_suspending(md) && + !WARN_ON_ONCE(dm_is_zone_write(md, bio))) || + handle_polled_eagain || first_stage) { + dm_requeue_add_io(io, first_stage); + requeued = true; + } else { + /* + * noflush suspend was interrupted or this is + * a write to a zoned target. + */ + io->status = BLK_STS_IOERR; + } + spin_unlock_irqrestore(&md->deferred_lock, flags); + } + + if (requeued) + dm_kick_requeue(md, first_stage); + + return requeued; +} + +static void __dm_io_complete(struct dm_io *io, bool first_stage) +{ + struct bio *bio = io->orig_bio; + struct mapped_device *md = io->md; + blk_status_t io_error; + bool requeued; + + requeued = dm_handle_requeue(io, first_stage); + if (requeued && first_stage) + return; + + io_error = io->status; + if (dm_io_flagged(io, DM_IO_ACCOUNTED)) + dm_end_io_acct(io); + else if (!io_error) { + /* + * Must handle target that DM_MAPIO_SUBMITTED only to + * then bio_endio() rather than dm_submit_bio_remap() + */ + __dm_start_io_acct(io); + dm_end_io_acct(io); + } + free_io(io); + smp_wmb(); + this_cpu_dec(*md->pending_io); + + /* nudge anyone waiting on suspend queue */ + if (unlikely(wq_has_sleeper(&md->wait))) + wake_up(&md->wait); + + /* Return early if the original bio was requeued */ + if (requeued) + return; + + if (bio_is_flush_with_data(bio)) { + /* + * Preflush done for flush with data, reissue + * without REQ_PREFLUSH. + */ + bio->bi_opf &= ~REQ_PREFLUSH; + queue_io(md, bio); + } else { + /* done with normal IO or empty flush */ + if (io_error) + bio->bi_status = io_error; + bio_endio(bio); + } +} + +static void dm_wq_requeue_work(struct work_struct *work) +{ + struct mapped_device *md = container_of(work, struct mapped_device, + requeue_work); + unsigned long flags; + struct dm_io *io; + + /* reuse deferred lock to simplify dm_handle_requeue */ + spin_lock_irqsave(&md->deferred_lock, flags); + io = md->requeue_list; + md->requeue_list = NULL; + spin_unlock_irqrestore(&md->deferred_lock, flags); + + while (io) { + struct dm_io *next = io->next; + + dm_io_rewind(io, &md->disk->bio_split); + + io->next = NULL; + __dm_io_complete(io, false); + io = next; + cond_resched(); + } +} + +/* + * Two staged requeue: + * + * 1) io->orig_bio points to the real original bio, and the part mapped to + * this io must be requeued, instead of other parts of the original bio. + * + * 2) io->orig_bio points to new cloned bio which matches the requeued dm_io. + */ +static void dm_io_complete(struct dm_io *io) +{ + bool first_requeue; + + /* + * Only dm_io that has been split needs two stage requeue, otherwise + * we may run into long bio clone chain during suspend and OOM could + * be triggered. + * + * Also flush data dm_io won't be marked as DM_IO_WAS_SPLIT, so they + * also aren't handled via the first stage requeue. + */ + if (dm_io_flagged(io, DM_IO_WAS_SPLIT)) + first_requeue = true; + else + first_requeue = false; + + __dm_io_complete(io, first_requeue); +} + +/* + * Decrements the number of outstanding ios that a bio has been + * cloned into, completing the original io if necc. + */ +static inline void __dm_io_dec_pending(struct dm_io *io) +{ + if (atomic_dec_and_test(&io->io_count)) + dm_io_complete(io); +} + +static void dm_io_set_error(struct dm_io *io, blk_status_t error) +{ + unsigned long flags; + + /* Push-back supersedes any I/O errors */ + spin_lock_irqsave(&io->lock, flags); + if (!(io->status == BLK_STS_DM_REQUEUE && + __noflush_suspending(io->md))) { + io->status = error; + } + spin_unlock_irqrestore(&io->lock, flags); +} + +static void dm_io_dec_pending(struct dm_io *io, blk_status_t error) +{ + if (unlikely(error)) + dm_io_set_error(io, error); + + __dm_io_dec_pending(io); +} + +void disable_discard(struct mapped_device *md) +{ + struct queue_limits *limits = dm_get_queue_limits(md); + + /* device doesn't really support DISCARD, disable it */ + limits->max_discard_sectors = 0; +} + +void disable_write_zeroes(struct mapped_device *md) +{ + struct queue_limits *limits = dm_get_queue_limits(md); + + /* device doesn't really support WRITE ZEROES, disable it */ + limits->max_write_zeroes_sectors = 0; +} + +static bool swap_bios_limit(struct dm_target *ti, struct bio *bio) +{ + return unlikely((bio->bi_opf & REQ_SWAP) != 0) && unlikely(ti->limit_swap_bios); +} + +static void clone_endio(struct bio *bio) +{ + blk_status_t error = bio->bi_status; + struct dm_target_io *tio = clone_to_tio(bio); + struct dm_target *ti = tio->ti; + dm_endio_fn endio = ti->type->end_io; + struct dm_io *io = tio->io; + struct mapped_device *md = io->md; + + if (unlikely(error == BLK_STS_TARGET)) { + if (bio_op(bio) == REQ_OP_DISCARD && + !bdev_max_discard_sectors(bio->bi_bdev)) + disable_discard(md); + else if (bio_op(bio) == REQ_OP_WRITE_ZEROES && + !bdev_write_zeroes_sectors(bio->bi_bdev)) + disable_write_zeroes(md); + } + + if (static_branch_unlikely(&zoned_enabled) && + unlikely(bdev_is_zoned(bio->bi_bdev))) + dm_zone_endio(io, bio); + + if (endio) { + int r = endio(ti, bio, &error); + switch (r) { + case DM_ENDIO_REQUEUE: + if (static_branch_unlikely(&zoned_enabled)) { + /* + * Requeuing writes to a sequential zone of a zoned + * target will break the sequential write pattern: + * fail such IO. + */ + if (WARN_ON_ONCE(dm_is_zone_write(md, bio))) + error = BLK_STS_IOERR; + else + error = BLK_STS_DM_REQUEUE; + } else + error = BLK_STS_DM_REQUEUE; + fallthrough; + case DM_ENDIO_DONE: + break; + case DM_ENDIO_INCOMPLETE: + /* The target will handle the io */ + return; + default: + DMCRIT("unimplemented target endio return value: %d", r); + BUG(); + } + } + + if (static_branch_unlikely(&swap_bios_enabled) && + unlikely(swap_bios_limit(ti, bio))) + up(&md->swap_bios_semaphore); + + free_tio(bio); + dm_io_dec_pending(io, error); +} + +/* + * Return maximum size of I/O possible at the supplied sector up to the current + * target boundary. + */ +static inline sector_t max_io_len_target_boundary(struct dm_target *ti, + sector_t target_offset) +{ + return ti->len - target_offset; +} + +static sector_t max_io_len(struct dm_target *ti, sector_t sector) +{ + sector_t target_offset = dm_target_offset(ti, sector); + sector_t len = max_io_len_target_boundary(ti, target_offset); + + /* + * Does the target need to split IO even further? + * - varied (per target) IO splitting is a tenet of DM; this + * explains why stacked chunk_sectors based splitting via + * bio_split_to_limits() isn't possible here. + */ + if (!ti->max_io_len) + return len; + return min_t(sector_t, len, + min(queue_max_sectors(ti->table->md->queue), + blk_chunk_sectors_left(target_offset, ti->max_io_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 struct dm_target *dm_dax_get_live_target(struct mapped_device *md, + sector_t sector, int *srcu_idx) + __acquires(md->io_barrier) +{ + struct dm_table *map; + struct dm_target *ti; + + map = dm_get_live_table(md, srcu_idx); + if (!map) + return NULL; + + ti = dm_table_find_target(map, sector); + if (!ti) + return NULL; + + return ti; +} + +static long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, + long nr_pages, enum dax_access_mode mode, void **kaddr, + pfn_t *pfn) +{ + struct mapped_device *md = dax_get_private(dax_dev); + sector_t sector = pgoff * PAGE_SECTORS; + struct dm_target *ti; + long len, ret = -EIO; + int srcu_idx; + + ti = dm_dax_get_live_target(md, sector, &srcu_idx); + + if (!ti) + goto out; + if (!ti->type->direct_access) + goto out; + len = max_io_len(ti, sector) / PAGE_SECTORS; + if (len < 1) + goto out; + nr_pages = min(len, nr_pages); + ret = ti->type->direct_access(ti, pgoff, nr_pages, mode, kaddr, pfn); + + out: + dm_put_live_table(md, srcu_idx); + + return ret; +} + +static int dm_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, + size_t nr_pages) +{ + struct mapped_device *md = dax_get_private(dax_dev); + sector_t sector = pgoff * PAGE_SECTORS; + struct dm_target *ti; + int ret = -EIO; + int srcu_idx; + + ti = dm_dax_get_live_target(md, sector, &srcu_idx); + + if (!ti) + goto out; + if (WARN_ON(!ti->type->dax_zero_page_range)) { + /* + * ->zero_page_range() is mandatory dax operation. If we are + * here, something is wrong. + */ + goto out; + } + ret = ti->type->dax_zero_page_range(ti, pgoff, nr_pages); + out: + dm_put_live_table(md, srcu_idx); + + return ret; +} + +static size_t dm_dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff, + void *addr, size_t bytes, struct iov_iter *i) +{ + struct mapped_device *md = dax_get_private(dax_dev); + sector_t sector = pgoff * PAGE_SECTORS; + struct dm_target *ti; + int srcu_idx; + long ret = 0; + + ti = dm_dax_get_live_target(md, sector, &srcu_idx); + if (!ti || !ti->type->dax_recovery_write) + goto out; + + ret = ti->type->dax_recovery_write(ti, pgoff, addr, bytes, i); +out: + dm_put_live_table(md, srcu_idx); + return ret; +} + +/* + * A target may call dm_accept_partial_bio only from the map routine. It is + * allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_* zone management + * operations, REQ_OP_ZONE_APPEND (zone append writes) and any bio serviced by + * __send_duplicate_bios(). + * + * 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 ---------------> + * <----- bio_sectors -----> + * <-- 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 int n_sectors) +{ + struct dm_target_io *tio = clone_to_tio(bio); + struct dm_io *io = tio->io; + unsigned int bio_sectors = bio_sectors(bio); + + BUG_ON(dm_tio_flagged(tio, DM_TIO_IS_DUPLICATE_BIO)); + BUG_ON(op_is_zone_mgmt(bio_op(bio))); + BUG_ON(bio_op(bio) == REQ_OP_ZONE_APPEND); + BUG_ON(bio_sectors > *tio->len_ptr); + BUG_ON(n_sectors > bio_sectors); + + *tio->len_ptr -= bio_sectors - n_sectors; + bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT; + + /* + * __split_and_process_bio() may have already saved mapped part + * for accounting but it is being reduced so update accordingly. + */ + dm_io_set_flag(io, DM_IO_WAS_SPLIT); + io->sectors = n_sectors; + io->sector_offset = bio_sectors(io->orig_bio); +} +EXPORT_SYMBOL_GPL(dm_accept_partial_bio); + +/* + * @clone: clone bio that DM core passed to target's .map function + * @tgt_clone: clone of @clone bio that target needs submitted + * + * Targets should use this interface to submit bios they take + * ownership of when returning DM_MAPIO_SUBMITTED. + * + * Target should also enable ti->accounts_remapped_io + */ +void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone) +{ + struct dm_target_io *tio = clone_to_tio(clone); + struct dm_io *io = tio->io; + + /* establish bio that will get submitted */ + if (!tgt_clone) + tgt_clone = clone; + + /* + * Account io->origin_bio to DM dev on behalf of target + * that took ownership of IO with DM_MAPIO_SUBMITTED. + */ + dm_start_io_acct(io, clone); + + trace_block_bio_remap(tgt_clone, disk_devt(io->md->disk), + tio->old_sector); + submit_bio_noacct(tgt_clone); +} +EXPORT_SYMBOL_GPL(dm_submit_bio_remap); + +static noinline void __set_swap_bios_limit(struct mapped_device *md, int latch) +{ + mutex_lock(&md->swap_bios_lock); + while (latch < md->swap_bios) { + cond_resched(); + down(&md->swap_bios_semaphore); + md->swap_bios--; + } + while (latch > md->swap_bios) { + cond_resched(); + up(&md->swap_bios_semaphore); + md->swap_bios++; + } + mutex_unlock(&md->swap_bios_lock); +} + +static void __map_bio(struct bio *clone) +{ + struct dm_target_io *tio = clone_to_tio(clone); + struct dm_target *ti = tio->ti; + struct dm_io *io = tio->io; + struct mapped_device *md = io->md; + int r; + + clone->bi_end_io = clone_endio; + + /* + * Map the clone. + */ + tio->old_sector = clone->bi_iter.bi_sector; + + if (static_branch_unlikely(&swap_bios_enabled) && + unlikely(swap_bios_limit(ti, clone))) { + int latch = get_swap_bios(); + if (unlikely(latch != md->swap_bios)) + __set_swap_bios_limit(md, latch); + down(&md->swap_bios_semaphore); + } + + if (static_branch_unlikely(&zoned_enabled)) { + /* + * Check if the IO needs a special mapping due to zone append + * emulation on zoned target. In this case, dm_zone_map_bio() + * calls the target map operation. + */ + if (unlikely(dm_emulate_zone_append(md))) + r = dm_zone_map_bio(tio); + else + r = ti->type->map(ti, clone); + } else + r = ti->type->map(ti, clone); + + switch (r) { + case DM_MAPIO_SUBMITTED: + /* target has assumed ownership of this io */ + if (!ti->accounts_remapped_io) + dm_start_io_acct(io, clone); + break; + case DM_MAPIO_REMAPPED: + dm_submit_bio_remap(clone, NULL); + break; + case DM_MAPIO_KILL: + case DM_MAPIO_REQUEUE: + if (static_branch_unlikely(&swap_bios_enabled) && + unlikely(swap_bios_limit(ti, clone))) + up(&md->swap_bios_semaphore); + free_tio(clone); + if (r == DM_MAPIO_KILL) + dm_io_dec_pending(io, BLK_STS_IOERR); + else + dm_io_dec_pending(io, BLK_STS_DM_REQUEUE); + break; + default: + DMCRIT("unimplemented target map return value: %d", r); + BUG(); + } +} + +static void setup_split_accounting(struct clone_info *ci, unsigned int len) +{ + struct dm_io *io = ci->io; + + if (ci->sector_count > len) { + /* + * Split needed, save the mapped part for accounting. + * NOTE: dm_accept_partial_bio() will update accordingly. + */ + dm_io_set_flag(io, DM_IO_WAS_SPLIT); + io->sectors = len; + io->sector_offset = bio_sectors(ci->bio); + } +} + +static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci, + struct dm_target *ti, unsigned int num_bios, + unsigned *len) +{ + struct bio *bio; + int try; + + for (try = 0; try < 2; try++) { + int bio_nr; + + if (try) + mutex_lock(&ci->io->md->table_devices_lock); + for (bio_nr = 0; bio_nr < num_bios; bio_nr++) { + bio = alloc_tio(ci, ti, bio_nr, len, + try ? GFP_NOIO : GFP_NOWAIT); + if (!bio) + break; + + bio_list_add(blist, bio); + } + if (try) + mutex_unlock(&ci->io->md->table_devices_lock); + if (bio_nr == num_bios) + return; + + while ((bio = bio_list_pop(blist))) + free_tio(bio); + } +} + +static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti, + unsigned int num_bios, unsigned int *len) +{ + struct bio_list blist = BIO_EMPTY_LIST; + struct bio *clone; + unsigned int ret = 0; + + switch (num_bios) { + case 0: + break; + case 1: + if (len) + setup_split_accounting(ci, *len); + clone = alloc_tio(ci, ti, 0, len, GFP_NOIO); + __map_bio(clone); + ret = 1; + break; + default: + if (len) + setup_split_accounting(ci, *len); + /* dm_accept_partial_bio() is not supported with shared tio->len_ptr */ + alloc_multiple_bios(&blist, ci, ti, num_bios, len); + while ((clone = bio_list_pop(&blist))) { + dm_tio_set_flag(clone_to_tio(clone), DM_TIO_IS_DUPLICATE_BIO); + __map_bio(clone); + ret += 1; + } + break; + } + + return ret; +} + +static void __send_empty_flush(struct clone_info *ci) +{ + struct dm_table *t = ci->map; + struct bio flush_bio; + + /* + * Use an on-stack bio for this, it's safe since we don't + * need to reference it after submit. It's just used as + * the basis for the clone(s). + */ + bio_init(&flush_bio, ci->io->md->disk->part0, NULL, 0, + REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC); + + ci->bio = &flush_bio; + ci->sector_count = 0; + ci->io->tio.clone.bi_iter.bi_size = 0; + + for (unsigned int i = 0; i < t->num_targets; i++) { + unsigned int bios; + struct dm_target *ti = dm_table_get_target(t, i); + + atomic_add(ti->num_flush_bios, &ci->io->io_count); + bios = __send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL); + atomic_sub(ti->num_flush_bios - bios, &ci->io->io_count); + } + + /* + * alloc_io() takes one extra reference for submission, so the + * reference won't reach 0 without the following subtraction + */ + atomic_sub(1, &ci->io->io_count); + + bio_uninit(ci->bio); +} + +static void __send_changing_extent_only(struct clone_info *ci, struct dm_target *ti, + unsigned int num_bios) +{ + unsigned int len, bios; + + len = min_t(sector_t, ci->sector_count, + max_io_len_target_boundary(ti, dm_target_offset(ti, ci->sector))); + + atomic_add(num_bios, &ci->io->io_count); + bios = __send_duplicate_bios(ci, ti, num_bios, &len); + /* + * alloc_io() takes one extra reference for submission, so the + * reference won't reach 0 without the following (+1) subtraction + */ + atomic_sub(num_bios - bios + 1, &ci->io->io_count); + + ci->sector += len; + ci->sector_count -= len; +} + +static bool is_abnormal_io(struct bio *bio) +{ + enum req_op op = bio_op(bio); + + if (op != REQ_OP_READ && op != REQ_OP_WRITE && op != REQ_OP_FLUSH) { + switch (op) { + case REQ_OP_DISCARD: + case REQ_OP_SECURE_ERASE: + case REQ_OP_WRITE_ZEROES: + return true; + default: + break; + } + } + + return false; +} + +static blk_status_t __process_abnormal_io(struct clone_info *ci, + struct dm_target *ti) +{ + unsigned int num_bios = 0; + + switch (bio_op(ci->bio)) { + case REQ_OP_DISCARD: + num_bios = ti->num_discard_bios; + break; + case REQ_OP_SECURE_ERASE: + num_bios = ti->num_secure_erase_bios; + break; + case REQ_OP_WRITE_ZEROES: + num_bios = ti->num_write_zeroes_bios; + break; + default: + break; + } + + /* + * 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. + */ + if (unlikely(!num_bios)) + return BLK_STS_NOTSUPP; + + __send_changing_extent_only(ci, ti, num_bios); + return BLK_STS_OK; +} + +/* + * Reuse ->bi_private as dm_io list head for storing all dm_io instances + * associated with this bio, and this bio's bi_private needs to be + * stored in dm_io->data before the reuse. + * + * bio->bi_private is owned by fs or upper layer, so block layer won't + * touch it after splitting. Meantime it won't be changed by anyone after + * bio is submitted. So this reuse is safe. + */ +static inline struct dm_io **dm_poll_list_head(struct bio *bio) +{ + return (struct dm_io **)&bio->bi_private; +} + +static void dm_queue_poll_io(struct bio *bio, struct dm_io *io) +{ + struct dm_io **head = dm_poll_list_head(bio); + + if (!(bio->bi_opf & REQ_DM_POLL_LIST)) { + bio->bi_opf |= REQ_DM_POLL_LIST; + /* + * Save .bi_private into dm_io, so that we can reuse + * .bi_private as dm_io list head for storing dm_io list + */ + io->data = bio->bi_private; + + /* tell block layer to poll for completion */ + bio->bi_cookie = ~BLK_QC_T_NONE; + + io->next = NULL; + } else { + /* + * bio recursed due to split, reuse original poll list, + * and save bio->bi_private too. + */ + io->data = (*head)->data; + io->next = *head; + } + + *head = io; +} + +/* + * Select the correct strategy for processing a non-flush bio. + */ +static blk_status_t __split_and_process_bio(struct clone_info *ci) +{ + struct bio *clone; + struct dm_target *ti; + unsigned int len; + + ti = dm_table_find_target(ci->map, ci->sector); + if (unlikely(!ti)) + return BLK_STS_IOERR; + + if (unlikely((ci->bio->bi_opf & REQ_NOWAIT) != 0) && + unlikely(!dm_target_supports_nowait(ti->type))) + return BLK_STS_NOTSUPP; + + if (unlikely(ci->is_abnormal_io)) + return __process_abnormal_io(ci, ti); + + /* + * Only support bio polling for normal IO, and the target io is + * exactly inside the dm_io instance (verified in dm_poll_dm_io) + */ + ci->submit_as_polled = !!(ci->bio->bi_opf & REQ_POLLED); + + len = min_t(sector_t, max_io_len(ti, ci->sector), ci->sector_count); + setup_split_accounting(ci, len); + clone = alloc_tio(ci, ti, 0, &len, GFP_NOIO); + __map_bio(clone); + + ci->sector += len; + ci->sector_count -= len; + + return BLK_STS_OK; +} + +static void init_clone_info(struct clone_info *ci, struct mapped_device *md, + struct dm_table *map, struct bio *bio, bool is_abnormal) +{ + ci->map = map; + ci->io = alloc_io(md, bio); + ci->bio = bio; + ci->is_abnormal_io = is_abnormal; + ci->submit_as_polled = false; + ci->sector = bio->bi_iter.bi_sector; + ci->sector_count = bio_sectors(bio); + + /* Shouldn't happen but sector_count was being set to 0 so... */ + if (static_branch_unlikely(&zoned_enabled) && + WARN_ON_ONCE(op_is_zone_mgmt(bio_op(bio)) && ci->sector_count)) + ci->sector_count = 0; +} + +/* + * Entry point to split a bio into clones and submit them to the targets. + */ +static void dm_split_and_process_bio(struct mapped_device *md, + struct dm_table *map, struct bio *bio) +{ + struct clone_info ci; + struct dm_io *io; + blk_status_t error = BLK_STS_OK; + bool is_abnormal; + + is_abnormal = is_abnormal_io(bio); + if (unlikely(is_abnormal)) { + /* + * Use bio_split_to_limits() for abnormal IO (e.g. discard, etc) + * otherwise associated queue_limits won't be imposed. + */ + bio = bio_split_to_limits(bio); + if (!bio) + return; + } + + init_clone_info(&ci, md, map, bio, is_abnormal); + io = ci.io; + + if (bio->bi_opf & REQ_PREFLUSH) { + __send_empty_flush(&ci); + /* dm_io_complete submits any data associated with flush */ + goto out; + } + + error = __split_and_process_bio(&ci); + if (error || !ci.sector_count) + goto out; + /* + * Remainder must be passed to submit_bio_noacct() so it gets handled + * *after* bios already submitted have been completely processed. + */ + bio_trim(bio, io->sectors, ci.sector_count); + trace_block_split(bio, bio->bi_iter.bi_sector); + bio_inc_remaining(bio); + submit_bio_noacct(bio); +out: + /* + * Drop the extra reference count for non-POLLED bio, and hold one + * reference for POLLED bio, which will be released in dm_poll_bio + * + * Add every dm_io instance into the dm_io list head which is stored + * in bio->bi_private, so that dm_poll_bio can poll them all. + */ + if (error || !ci.submit_as_polled) { + /* + * In case of submission failure, the extra reference for + * submitting io isn't consumed yet + */ + if (error) + atomic_dec(&io->io_count); + dm_io_dec_pending(io, error); + } else + dm_queue_poll_io(bio, io); +} + +static void dm_submit_bio(struct bio *bio) +{ + struct mapped_device *md = bio->bi_bdev->bd_disk->private_data; + int srcu_idx; + struct dm_table *map; + + map = dm_get_live_table(md, &srcu_idx); + + /* If suspended, or map not yet available, queue this IO for later */ + if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) || + unlikely(!map)) { + if (bio->bi_opf & REQ_NOWAIT) + bio_wouldblock_error(bio); + else if (bio->bi_opf & REQ_RAHEAD) + bio_io_error(bio); + else + queue_io(md, bio); + goto out; + } + + dm_split_and_process_bio(md, map, bio); +out: + dm_put_live_table(md, srcu_idx); +} + +static bool dm_poll_dm_io(struct dm_io *io, struct io_comp_batch *iob, + unsigned int flags) +{ + WARN_ON_ONCE(!dm_tio_is_normal(&io->tio)); + + /* don't poll if the mapped io is done */ + if (atomic_read(&io->io_count) > 1) + bio_poll(&io->tio.clone, iob, flags); + + /* bio_poll holds the last reference */ + return atomic_read(&io->io_count) == 1; +} + +static int dm_poll_bio(struct bio *bio, struct io_comp_batch *iob, + unsigned int flags) +{ + struct dm_io **head = dm_poll_list_head(bio); + struct dm_io *list = *head; + struct dm_io *tmp = NULL; + struct dm_io *curr, *next; + + /* Only poll normal bio which was marked as REQ_DM_POLL_LIST */ + if (!(bio->bi_opf & REQ_DM_POLL_LIST)) + return 0; + + WARN_ON_ONCE(!list); + + /* + * Restore .bi_private before possibly completing dm_io. + * + * bio_poll() is only possible once @bio has been completely + * submitted via submit_bio_noacct()'s depth-first submission. + * So there is no dm_queue_poll_io() race associated with + * clearing REQ_DM_POLL_LIST here. + */ + bio->bi_opf &= ~REQ_DM_POLL_LIST; + bio->bi_private = list->data; + + for (curr = list, next = curr->next; curr; curr = next, next = + curr ? curr->next : NULL) { + if (dm_poll_dm_io(curr, iob, flags)) { + /* + * clone_endio() has already occurred, so no + * error handling is needed here. + */ + __dm_io_dec_pending(curr); + } else { + curr->next = tmp; + tmp = curr; + } + } + + /* Not done? */ + if (tmp) { + bio->bi_opf |= REQ_DM_POLL_LIST; + /* Reset bio->bi_private to dm_io list head */ + *head = tmp; + return 0; + } + return 1; +} + +/*----------------------------------------------------------------- + * 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 const struct block_device_operations dm_rq_blk_dops; +static const struct dax_operations dm_dax_ops; + +static void dm_wq_work(struct work_struct *work); + +#ifdef CONFIG_BLK_INLINE_ENCRYPTION +static void dm_queue_destroy_crypto_profile(struct request_queue *q) +{ + dm_destroy_crypto_profile(q->crypto_profile); +} + +#else /* CONFIG_BLK_INLINE_ENCRYPTION */ + +static inline void dm_queue_destroy_crypto_profile(struct request_queue *q) +{ +} +#endif /* !CONFIG_BLK_INLINE_ENCRYPTION */ + +static void cleanup_mapped_device(struct mapped_device *md) +{ + if (md->wq) + destroy_workqueue(md->wq); + dm_free_md_mempools(md->mempools); + + if (md->dax_dev) { + dax_remove_host(md->disk); + kill_dax(md->dax_dev); + put_dax(md->dax_dev); + md->dax_dev = NULL; + } + + dm_cleanup_zoned_dev(md); + if (md->disk) { + spin_lock(&_minor_lock); + md->disk->private_data = NULL; + spin_unlock(&_minor_lock); + if (dm_get_md_type(md) != DM_TYPE_NONE) { + struct table_device *td; + + dm_sysfs_exit(md); + list_for_each_entry(td, &md->table_devices, list) { + bd_unlink_disk_holder(td->dm_dev.bdev, + md->disk); + } + + /* + * Hold lock to make sure del_gendisk() won't concurrent + * with open/close_table_device(). + */ + mutex_lock(&md->table_devices_lock); + del_gendisk(md->disk); + mutex_unlock(&md->table_devices_lock); + } + dm_queue_destroy_crypto_profile(md->queue); + put_disk(md->disk); + } + + if (md->pending_io) { + free_percpu(md->pending_io); + md->pending_io = NULL; + } + + cleanup_srcu_struct(&md->io_barrier); + + mutex_destroy(&md->suspend_lock); + mutex_destroy(&md->type_lock); + mutex_destroy(&md->table_devices_lock); + mutex_destroy(&md->swap_bios_lock); + + dm_mq_cleanup_mapped_device(md); +} + +/* + * Allocate and initialise a blank device with a given minor. + */ +static struct mapped_device *alloc_dev(int minor) +{ + int r, numa_node_id = dm_get_numa_node(); + struct mapped_device *md; + void *old_md; + + md = kvzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id); + if (!md) { + DMERR("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->numa_node_id = numa_node_id; + md->init_tio_pdu = false; + 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); + + /* + * default to bio-based until DM table is loaded and md->type + * established. If request-based table is loaded: blk-mq will + * override accordingly. + */ + md->disk = blk_alloc_disk(md->numa_node_id); + if (!md->disk) + goto bad; + md->queue = md->disk->queue; + + init_waitqueue_head(&md->wait); + INIT_WORK(&md->work, dm_wq_work); + INIT_WORK(&md->requeue_work, dm_wq_requeue_work); + init_waitqueue_head(&md->eventq); + init_completion(&md->kobj_holder.completion); + + md->requeue_list = NULL; + md->swap_bios = get_swap_bios(); + sema_init(&md->swap_bios_semaphore, md->swap_bios); + mutex_init(&md->swap_bios_lock); + + md->disk->major = _major; + md->disk->first_minor = minor; + md->disk->minors = 1; + md->disk->flags |= GENHD_FL_NO_PART; + md->disk->fops = &dm_blk_dops; + md->disk->private_data = md; + sprintf(md->disk->disk_name, "dm-%d", minor); + + if (IS_ENABLED(CONFIG_FS_DAX)) { + md->dax_dev = alloc_dax(md, &dm_dax_ops); + if (IS_ERR(md->dax_dev)) { + md->dax_dev = NULL; + goto bad; + } + set_dax_nocache(md->dax_dev); + set_dax_nomc(md->dax_dev); + if (dax_add_host(md->dax_dev, md->disk)) + goto bad; + } + + format_dev_t(md->name, MKDEV(_major, minor)); + + md->wq = alloc_workqueue("kdmflush/%s", WQ_MEM_RECLAIM, 0, md->name); + if (!md->wq) + goto bad; + + md->pending_io = alloc_percpu(unsigned long); + if (!md->pending_io) + goto bad; + + r = dm_stats_init(&md->stats); + if (r < 0) + goto bad; + + /* 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: + kvfree(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); + + free_table_devices(&md->table_devices); + dm_stats_cleanup(&md->stats); + free_minor(minor); + + module_put(THIS_MODULE); + kvfree(md); +} + +/* + * 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); + dm_issue_global_event(); +} + +/* + * 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; + sector_t size; + int ret; + + lockdep_assert_held(&md->suspend_lock); + + 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_capacity(md->disk, size); + + dm_table_event_callback(t, event_callback, md); + + if (dm_table_request_based(t)) { + /* + * Leverage the fact that request-based DM targets are + * immutable singletons - used to optimize dm_mq_queue_rq. + */ + md->immutable_target = dm_table_get_immutable_target(t); + + /* + * There is 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. + */ + if (!md->mempools) { + md->mempools = t->mempools; + t->mempools = NULL; + } + } else { + /* + * The md may already have mempools that need changing. + * If so, reload bioset because front_pad may have changed + * because a different table was loaded. + */ + dm_free_md_mempools(md->mempools); + md->mempools = t->mempools; + t->mempools = NULL; + } + + ret = dm_table_set_restrictions(t, md->queue, limits); + if (ret) { + old_map = ERR_PTR(ret); + goto out; + } + + old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock)); + rcu_assign_pointer(md->map, (void *)t); + md->immutable_target_type = dm_table_get_immutable_target_type(t); + + if (old_map) + dm_sync_table(md); +out: + 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_ima_reset_data(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, enum dm_queue_mode type) +{ + BUG_ON(!mutex_is_locked(&md->type_lock)); + md->type = type; +} + +enum dm_queue_mode 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); + +/* + * Setup the DM device's queue based on md's type + */ +int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t) +{ + enum dm_queue_mode type = dm_table_get_type(t); + struct queue_limits limits; + struct table_device *td; + int r; + + switch (type) { + case DM_TYPE_REQUEST_BASED: + md->disk->fops = &dm_rq_blk_dops; + r = dm_mq_init_request_queue(md, t); + if (r) { + DMERR("Cannot initialize queue for request-based dm mapped device"); + return r; + } + break; + case DM_TYPE_BIO_BASED: + case DM_TYPE_DAX_BIO_BASED: + break; + case DM_TYPE_NONE: + WARN_ON_ONCE(true); + break; + } + + r = dm_calculate_queue_limits(t, &limits); + if (r) { + DMERR("Cannot calculate initial queue limits"); + return r; + } + r = dm_table_set_restrictions(t, md->queue, &limits); + if (r) + return r; + + /* + * Hold lock to make sure add_disk() and del_gendisk() won't concurrent + * with open_table_device() and close_table_device(). + */ + mutex_lock(&md->table_devices_lock); + r = add_disk(md->disk); + mutex_unlock(&md->table_devices_lock); + if (r) + return r; + + /* + * Register the holder relationship for devices added before the disk + * was live. + */ + list_for_each_entry(td, &md->table_devices, list) { + r = bd_link_disk_holder(td->dm_dev.bdev, md->disk); + if (r) + goto out_undo_holders; + } + + r = dm_sysfs_init(md); + if (r) + goto out_undo_holders; + + md->type = type; + return 0; + +out_undo_holders: + list_for_each_entry_continue_reverse(td, &md->table_devices, list) + bd_unlink_disk_holder(td->dm_dev.bdev, md->disk); + mutex_lock(&md->table_devices_lock); + del_gendisk(md->disk); + mutex_unlock(&md->table_devices_lock); + return r; +} + +struct mapped_device *dm_get_md(dev_t dev) +{ + struct mapped_device *md; + unsigned int 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) || + test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) { + 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); + + blk_mark_disk_dead(md->disk); + + /* + * 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); + set_bit(DMF_SUSPENDED, &md->flags); + set_bit(DMF_POST_SUSPENDING, &md->flags); + 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_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 bool dm_in_flight_bios(struct mapped_device *md) +{ + int cpu; + unsigned long sum = 0; + + for_each_possible_cpu(cpu) + sum += *per_cpu_ptr(md->pending_io, cpu); + + return sum != 0; +} + +static int dm_wait_for_bios_completion(struct mapped_device *md, unsigned int task_state) +{ + int r = 0; + DEFINE_WAIT(wait); + + while (true) { + prepare_to_wait(&md->wait, &wait, task_state); + + if (!dm_in_flight_bios(md)) + break; + + if (signal_pending_state(task_state, current)) { + r = -EINTR; + break; + } + + io_schedule(); + } + finish_wait(&md->wait, &wait); + + smp_rmb(); + + return r; +} + +static int dm_wait_for_completion(struct mapped_device *md, unsigned int task_state) +{ + int r = 0; + + if (!queue_is_mq(md->queue)) + return dm_wait_for_bios_completion(md, task_state); + + while (true) { + if (!blk_mq_queue_inflight(md->queue)) + break; + + if (signal_pending_state(task_state, current)) { + r = -EINTR; + break; + } + + msleep(5); + } + + 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 *bio; + + while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { + spin_lock_irq(&md->deferred_lock); + bio = bio_list_pop(&md->deferred); + spin_unlock_irq(&md->deferred_lock); + + if (!bio) + break; + + submit_bio_noacct(bio); + cond_resched(); + } +} + +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); + dm_issue_global_event(); + +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(test_bit(DMF_FROZEN, &md->flags)); + + r = freeze_bdev(md->disk->part0); + if (!r) + set_bit(DMF_FROZEN, &md->flags); + return r; +} + +static void unlock_fs(struct mapped_device *md) +{ + if (!test_bit(DMF_FROZEN, &md->flags)) + return; + thaw_bdev(md->disk->part0); + clear_bit(DMF_FROZEN, &md->flags); +} + +/* + * @suspend_flags: DM_SUSPEND_LOCKFS_FLAG and/or DM_SUSPEND_NOFLUSH_FLAG + * @task_state: e.g. TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE + * @dmf_suspended_flag: DMF_SUSPENDED or DMF_SUSPENDED_INTERNALLY + * + * 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. + */ +static int __dm_suspend(struct mapped_device *md, struct dm_table *map, + unsigned int suspend_flags, unsigned int task_state, + int dmf_suspended_flag) +{ + bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG; + bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG; + int r; + + lockdep_assert_held(&md->suspend_lock); + + /* + * 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); + else + DMDEBUG("%s: suspending with flush", dm_device_name(md)); + + /* + * 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 + * dm_split_and_process_bio from dm_submit_bio. + * + * To get all processes out of dm_split_and_process_bio in dm_submit_bio, + * we take the write lock. To prevent any process from reentering + * dm_split_and_process_bio from dm_submit_bio and quiesce the thread + * (dm_wq_work), we set DMF_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)) + dm_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_state); + if (!r) + set_bit(dmf_suspended_flag, &md->flags); + + 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)) + dm_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 int 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)); + if (!map) { + /* avoid deadlock with fs/namespace.c:do_mount() */ + suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; + } + + r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE, DMF_SUSPENDED); + if (r) + goto out_unlock; + + set_bit(DMF_POST_SUSPENDING, &md->flags); + dm_table_postsuspend_targets(map); + clear_bit(DMF_POST_SUSPENDING, &md->flags); + +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)) + dm_start_queue(md->queue); + + unlock_fs(md); + + return 0; +} + +int dm_resume(struct mapped_device *md) +{ + int r; + struct dm_table *map = NULL; + +retry: + r = -EINVAL; + 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); +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 int suspend_flags) +{ + struct dm_table *map = NULL; + + lockdep_assert_held(&md->suspend_lock); + + 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, + DMF_SUSPENDED_INTERNALLY); + + set_bit(DMF_POST_SUSPENDING, &md->flags); + dm_table_postsuspend_targets(map); + clear_bit(DMF_POST_SUSPENDING, &md->flags); +} + +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 int cookie, bool need_resize_uevent) +{ + int r; + unsigned int noio_flag; + char udev_cookie[DM_COOKIE_LENGTH]; + char *envp[3] = { NULL, NULL, NULL }; + char **envpp = envp; + if (cookie) { + snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u", + DM_COOKIE_ENV_VAR_NAME, cookie); + *envpp++ = udev_cookie; + } + if (need_resize_uevent) { + *envpp++ = "RESIZE=1"; + } + + noio_flag = memalloc_noio_save(); + + r = kobject_uevent_env(&disk_to_dev(md->disk)->kobj, action, envp); + + memalloc_noio_restore(noio_flag); + + return r; +} + +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); + + spin_lock(&_minor_lock); + if (test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) { + md = NULL; + goto out; + } + dm_get(md); +out: + spin_unlock(&_minor_lock); + + return md; +} + +int dm_suspended_md(struct mapped_device *md) +{ + return test_bit(DMF_SUSPENDED, &md->flags); +} + +static int dm_post_suspending_md(struct mapped_device *md) +{ + return test_bit(DMF_POST_SUSPENDING, &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(ti->table->md); +} +EXPORT_SYMBOL_GPL(dm_suspended); + +int dm_post_suspending(struct dm_target *ti) +{ + return dm_post_suspending_md(ti->table->md); +} +EXPORT_SYMBOL_GPL(dm_post_suspending); + +int dm_noflush_suspending(struct dm_target *ti) +{ + return __noflush_suspending(ti->table->md); +} +EXPORT_SYMBOL_GPL(dm_noflush_suspending); + +void dm_free_md_mempools(struct dm_md_mempools *pools) +{ + if (!pools) + return; + + bioset_exit(&pools->bs); + bioset_exit(&pools->io_bs); + + kfree(pools); +} + +struct dm_pr { + u64 old_key; + u64 new_key; + u32 flags; + bool abort; + bool fail_early; + int ret; + enum pr_type type; +}; + +static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn, + struct dm_pr *pr) +{ + struct mapped_device *md = bdev->bd_disk->private_data; + struct dm_table *table; + struct dm_target *ti; + int ret = -ENOTTY, srcu_idx; + + table = dm_get_live_table(md, &srcu_idx); + if (!table || !dm_table_get_size(table)) + goto out; + + /* We only support devices that have a single target */ + if (table->num_targets != 1) + goto out; + ti = dm_table_get_target(table, 0); + + if (dm_suspended_md(md)) { + ret = -EAGAIN; + goto out; + } + + ret = -EINVAL; + if (!ti->type->iterate_devices) + goto out; + + ti->type->iterate_devices(ti, fn, pr); + ret = 0; +out: + dm_put_live_table(md, srcu_idx); + return ret; +} + +/* + * For register / unregister we need to manually call out to every path. + */ +static int __dm_pr_register(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *data) +{ + struct dm_pr *pr = data; + const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops; + int ret; + + if (!ops || !ops->pr_register) { + pr->ret = -EOPNOTSUPP; + return -1; + } + + ret = ops->pr_register(dev->bdev, pr->old_key, pr->new_key, pr->flags); + if (!ret) + return 0; + + if (!pr->ret) + pr->ret = ret; + + if (pr->fail_early) + return -1; + + return 0; +} + +static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key, + u32 flags) +{ + struct dm_pr pr = { + .old_key = old_key, + .new_key = new_key, + .flags = flags, + .fail_early = true, + .ret = 0, + }; + int ret; + + ret = dm_call_pr(bdev, __dm_pr_register, &pr); + if (ret) { + /* Didn't even get to register a path */ + return ret; + } + + if (!pr.ret) + return 0; + ret = pr.ret; + + if (!new_key) + return ret; + + /* unregister all paths if we failed to register any path */ + pr.old_key = new_key; + pr.new_key = 0; + pr.flags = 0; + pr.fail_early = false; + (void) dm_call_pr(bdev, __dm_pr_register, &pr); + return ret; +} + + +static int __dm_pr_reserve(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *data) +{ + struct dm_pr *pr = data; + const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops; + + if (!ops || !ops->pr_reserve) { + pr->ret = -EOPNOTSUPP; + return -1; + } + + pr->ret = ops->pr_reserve(dev->bdev, pr->old_key, pr->type, pr->flags); + if (!pr->ret) + return -1; + + return 0; +} + +static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type, + u32 flags) +{ + struct dm_pr pr = { + .old_key = key, + .flags = flags, + .type = type, + .fail_early = false, + .ret = 0, + }; + int ret; + + ret = dm_call_pr(bdev, __dm_pr_reserve, &pr); + if (ret) + return ret; + + return pr.ret; +} + +/* + * If there is a non-All Registrants type of reservation, the release must be + * sent down the holding path. For the cases where there is no reservation or + * the path is not the holder the device will also return success, so we must + * try each path to make sure we got the correct path. + */ +static int __dm_pr_release(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *data) +{ + struct dm_pr *pr = data; + const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops; + + if (!ops || !ops->pr_release) { + pr->ret = -EOPNOTSUPP; + return -1; + } + + pr->ret = ops->pr_release(dev->bdev, pr->old_key, pr->type); + if (pr->ret) + return -1; + + return 0; +} + +static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type) +{ + struct dm_pr pr = { + .old_key = key, + .type = type, + .fail_early = false, + }; + int ret; + + ret = dm_call_pr(bdev, __dm_pr_release, &pr); + if (ret) + return ret; + + return pr.ret; +} + +static int __dm_pr_preempt(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *data) +{ + struct dm_pr *pr = data; + const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops; + + if (!ops || !ops->pr_preempt) { + pr->ret = -EOPNOTSUPP; + return -1; + } + + pr->ret = ops->pr_preempt(dev->bdev, pr->old_key, pr->new_key, pr->type, + pr->abort); + if (!pr->ret) + return -1; + + return 0; +} + +static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key, + enum pr_type type, bool abort) +{ + struct dm_pr pr = { + .new_key = new_key, + .old_key = old_key, + .type = type, + .fail_early = false, + }; + int ret; + + ret = dm_call_pr(bdev, __dm_pr_preempt, &pr); + if (ret) + return ret; + + return pr.ret; +} + +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; + int r, srcu_idx; + + r = dm_prepare_ioctl(md, &srcu_idx, &bdev); + if (r < 0) + goto out; + + ops = bdev->bd_disk->fops->pr_ops; + if (ops && ops->pr_clear) + r = ops->pr_clear(bdev, key); + else + r = -EOPNOTSUPP; +out: + dm_unprepare_ioctl(md, srcu_idx); + 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 = { + .submit_bio = dm_submit_bio, + .poll_bio = dm_poll_bio, + .open = dm_blk_open, + .release = dm_blk_close, + .ioctl = dm_blk_ioctl, + .getgeo = dm_blk_getgeo, + .report_zones = dm_blk_report_zones, + .pr_ops = &dm_pr_ops, + .owner = THIS_MODULE +}; + +static const struct block_device_operations dm_rq_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 +}; + +static const struct dax_operations dm_dax_ops = { + .direct_access = dm_dax_direct_access, + .zero_page_range = dm_dax_zero_page_range, + .recovery_write = dm_dax_recovery_write, +}; + +/* + * 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(dm_numa_node, int, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(dm_numa_node, "NUMA node for DM device memory allocations"); + +module_param(swap_bios, int, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(swap_bios, "Maximum allowed inflight swap IOs"); + +MODULE_DESCRIPTION(DM_NAME " driver"); +MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); +MODULE_LICENSE("GPL"); |