| /* |
| * 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 <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/mutex.h> |
| #include <linux/moduleparam.h> |
| #include <linux/blkpg.h> |
| #include <linux/bio.h> |
| #include <linux/buffer_head.h> |
| #include <linux/smp_lock.h> |
| #include <linux/mempool.h> |
| #include <linux/slab.h> |
| #include <linux/idr.h> |
| #include <linux/hdreg.h> |
| #include <linux/delay.h> |
| |
| #include <trace/events/block.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 |
| |
| static const char *_name = DM_NAME; |
| |
| static unsigned int major = 0; |
| static unsigned int _major = 0; |
| |
| static DEFINE_SPINLOCK(_minor_lock); |
| /* |
| * For bio-based dm. |
| * One of these is allocated per bio. |
| */ |
| struct dm_io { |
| struct mapped_device *md; |
| int error; |
| atomic_t io_count; |
| struct bio *bio; |
| unsigned long start_time; |
| spinlock_t endio_lock; |
| }; |
| |
| /* |
| * For bio-based dm. |
| * One of these is allocated per target within a bio. Hopefully |
| * this will be simplified out one day. |
| */ |
| struct dm_target_io { |
| struct dm_io *io; |
| struct dm_target *ti; |
| union map_info info; |
| }; |
| |
| /* |
| * For request-based dm. |
| * One of these is allocated per request. |
| */ |
| struct dm_rq_target_io { |
| struct mapped_device *md; |
| struct dm_target *ti; |
| struct request *orig, clone; |
| int error; |
| union map_info info; |
| }; |
| |
| /* |
| * For request-based dm. |
| * One of these is allocated per bio. |
| */ |
| struct dm_rq_clone_bio_info { |
| struct bio *orig; |
| struct dm_rq_target_io *tio; |
| }; |
| |
| union map_info *dm_get_mapinfo(struct bio *bio) |
| { |
| if (bio && bio->bi_private) |
| return &((struct dm_target_io *)bio->bi_private)->info; |
| return NULL; |
| } |
| |
| union map_info *dm_get_rq_mapinfo(struct request *rq) |
| { |
| if (rq && rq->end_io_data) |
| return &((struct dm_rq_target_io *)rq->end_io_data)->info; |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo); |
| |
| #define MINOR_ALLOCED ((void *)-1) |
| |
| /* |
| * Bits for the md->flags field. |
| */ |
| #define DMF_BLOCK_IO_FOR_SUSPEND 0 |
| #define DMF_SUSPENDED 1 |
| #define DMF_FROZEN 2 |
| #define DMF_FREEING 3 |
| #define DMF_DELETING 4 |
| #define DMF_NOFLUSH_SUSPENDING 5 |
| #define DMF_QUEUE_IO_TO_THREAD 6 |
| |
| /* |
| * Work processed by per-device workqueue. |
| */ |
| struct mapped_device { |
| struct rw_semaphore io_lock; |
| struct mutex suspend_lock; |
| rwlock_t map_lock; |
| atomic_t holders; |
| atomic_t open_count; |
| |
| unsigned long flags; |
| |
| struct request_queue *queue; |
| unsigned type; |
| /* Protect queue and type against concurrent access. */ |
| struct mutex type_lock; |
| |
| struct 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; |
| |
| /* |
| * An error from the barrier request currently being processed. |
| */ |
| int barrier_error; |
| |
| /* |
| * Protect barrier_error from concurrent endio processing |
| * in request-based dm. |
| */ |
| spinlock_t barrier_error_lock; |
| |
| /* |
| * Processing queue (flush/barriers) |
| */ |
| struct workqueue_struct *wq; |
| struct work_struct barrier_work; |
| |
| /* A pointer to the currently processing pre/post flush request */ |
| struct request *flush_request; |
| |
| /* |
| * The current mapping. |
| */ |
| struct dm_table *map; |
| |
| /* |
| * io objects are allocated from here. |
| */ |
| mempool_t *io_pool; |
| mempool_t *tio_pool; |
| |
| struct bio_set *bs; |
| |
| /* |
| * Event handling. |
| */ |
| atomic_t event_nr; |
| wait_queue_head_t eventq; |
| atomic_t uevent_seq; |
| struct list_head uevent_list; |
| spinlock_t uevent_lock; /* Protect access to uevent_list */ |
| |
| /* |
| * freeze/thaw support require holding onto a super block |
| */ |
| struct super_block *frozen_sb; |
| struct block_device *bdev; |
| |
| /* forced geometry settings */ |
| struct hd_geometry geometry; |
| |
| /* For saving the address of __make_request for request based dm */ |
| make_request_fn *saved_make_request_fn; |
| |
| /* sysfs handle */ |
| struct kobject kobj; |
| |
| /* zero-length barrier that will be cloned and submitted to targets */ |
| struct bio barrier_bio; |
| }; |
| |
| /* |
| * For mempools pre-allocation at the table loading time. |
| */ |
| struct dm_md_mempools { |
| mempool_t *io_pool; |
| mempool_t *tio_pool; |
| struct bio_set *bs; |
| }; |
| |
| #define MIN_IOS 256 |
| static struct kmem_cache *_io_cache; |
| static struct kmem_cache *_tio_cache; |
| static struct kmem_cache *_rq_tio_cache; |
| static struct kmem_cache *_rq_bio_info_cache; |
| |
| static int __init local_init(void) |
| { |
| int r = -ENOMEM; |
| |
| /* allocate a slab for the dm_ios */ |
| _io_cache = KMEM_CACHE(dm_io, 0); |
| if (!_io_cache) |
| return r; |
| |
| /* allocate a slab for the target ios */ |
| _tio_cache = KMEM_CACHE(dm_target_io, 0); |
| if (!_tio_cache) |
| goto out_free_io_cache; |
| |
| _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0); |
| if (!_rq_tio_cache) |
| goto out_free_tio_cache; |
| |
| _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0); |
| if (!_rq_bio_info_cache) |
| goto out_free_rq_tio_cache; |
| |
| r = dm_uevent_init(); |
| if (r) |
| goto out_free_rq_bio_info_cache; |
| |
| _major = major; |
| r = register_blkdev(_major, _name); |
| if (r < 0) |
| goto out_uevent_exit; |
| |
| if (!_major) |
| _major = r; |
| |
| return 0; |
| |
| out_uevent_exit: |
| dm_uevent_exit(); |
| out_free_rq_bio_info_cache: |
| kmem_cache_destroy(_rq_bio_info_cache); |
| out_free_rq_tio_cache: |
| kmem_cache_destroy(_rq_tio_cache); |
| out_free_tio_cache: |
| kmem_cache_destroy(_tio_cache); |
| out_free_io_cache: |
| kmem_cache_destroy(_io_cache); |
| |
| return r; |
| } |
| |
| static void local_exit(void) |
| { |
| kmem_cache_destroy(_rq_bio_info_cache); |
| kmem_cache_destroy(_rq_tio_cache); |
| kmem_cache_destroy(_tio_cache); |
| kmem_cache_destroy(_io_cache); |
| unregister_blkdev(_major, _name); |
| dm_uevent_exit(); |
| |
| _major = 0; |
| |
| DMINFO("cleaned up"); |
| } |
| |
| static int (*_inits[])(void) __initdata = { |
| local_init, |
| dm_target_init, |
| dm_linear_init, |
| dm_stripe_init, |
| dm_io_init, |
| dm_kcopyd_init, |
| dm_interface_init, |
| }; |
| |
| static void (*_exits[])(void) = { |
| local_exit, |
| dm_target_exit, |
| dm_linear_exit, |
| dm_stripe_exit, |
| dm_io_exit, |
| dm_kcopyd_exit, |
| dm_interface_exit, |
| }; |
| |
| static int __init dm_init(void) |
| { |
| const int count = ARRAY_SIZE(_inits); |
| |
| int r, i; |
| |
| for (i = 0; i < count; i++) { |
| r = _inits[i](); |
| if (r) |
| goto bad; |
| } |
| |
| return 0; |
| |
| bad: |
| while (i--) |
| _exits[i](); |
| |
| return r; |
| } |
| |
| static void __exit dm_exit(void) |
| { |
| int i = ARRAY_SIZE(_exits); |
| |
| while (i--) |
| _exits[i](); |
| } |
| |
| /* |
| * 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; |
| |
| lock_kernel(); |
| 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); |
| unlock_kernel(); |
| |
| return md ? 0 : -ENXIO; |
| } |
| |
| static int dm_blk_close(struct gendisk *disk, fmode_t mode) |
| { |
| struct mapped_device *md = disk->private_data; |
| |
| lock_kernel(); |
| atomic_dec(&md->open_count); |
| dm_put(md); |
| unlock_kernel(); |
| |
| return 0; |
| } |
| |
| int dm_open_count(struct mapped_device *md) |
| { |
| return atomic_read(&md->open_count); |
| } |
| |
| /* |
| * Guarantees nothing is using the device before it's deleted. |
| */ |
| int dm_lock_for_deletion(struct mapped_device *md) |
| { |
| int r = 0; |
| |
| spin_lock(&_minor_lock); |
| |
| if (dm_open_count(md)) |
| r = -EBUSY; |
| else |
| set_bit(DMF_DELETING, &md->flags); |
| |
| spin_unlock(&_minor_lock); |
| |
| return r; |
| } |
| |
| static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo) |
| { |
| struct mapped_device *md = bdev->bd_disk->private_data; |
| |
| return dm_get_geometry(md, geo); |
| } |
| |
| static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode, |
| unsigned int cmd, unsigned long arg) |
| { |
| struct mapped_device *md = bdev->bd_disk->private_data; |
| struct dm_table *map = dm_get_live_table(md); |
| struct dm_target *tgt; |
| int r = -ENOTTY; |
| |
| if (!map || !dm_table_get_size(map)) |
| goto out; |
| |
| /* We only support devices that have a single target */ |
| if (dm_table_get_num_targets(map) != 1) |
| goto out; |
| |
| tgt = dm_table_get_target(map, 0); |
| |
| if (dm_suspended_md(md)) { |
| r = -EAGAIN; |
| goto out; |
| } |
| |
| if (tgt->type->ioctl) |
| r = tgt->type->ioctl(tgt, cmd, arg); |
| |
| out: |
| dm_table_put(map); |
| |
| return r; |
| } |
| |
| static struct dm_io *alloc_io(struct mapped_device *md) |
| { |
| return mempool_alloc(md->io_pool, GFP_NOIO); |
| } |
| |
| static void free_io(struct mapped_device *md, struct dm_io *io) |
| { |
| mempool_free(io, md->io_pool); |
| } |
| |
| static void free_tio(struct mapped_device *md, struct dm_target_io *tio) |
| { |
| mempool_free(tio, md->tio_pool); |
| } |
| |
| static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md, |
| gfp_t gfp_mask) |
| { |
| return mempool_alloc(md->tio_pool, gfp_mask); |
| } |
| |
| static void free_rq_tio(struct dm_rq_target_io *tio) |
| { |
| mempool_free(tio, tio->md->tio_pool); |
| } |
| |
| static struct dm_rq_clone_bio_info *alloc_bio_info(struct mapped_device *md) |
| { |
| return mempool_alloc(md->io_pool, GFP_ATOMIC); |
| } |
| |
| static void free_bio_info(struct dm_rq_clone_bio_info *info) |
| { |
| mempool_free(info, info->tio->md->io_pool); |
| } |
| |
| static int md_in_flight(struct mapped_device *md) |
| { |
| return atomic_read(&md->pending[READ]) + |
| atomic_read(&md->pending[WRITE]); |
| } |
| |
| static void start_io_acct(struct dm_io *io) |
| { |
| struct mapped_device *md = io->md; |
| int cpu; |
| int rw = bio_data_dir(io->bio); |
| |
| io->start_time = jiffies; |
| |
| cpu = part_stat_lock(); |
| part_round_stats(cpu, &dm_disk(md)->part0); |
| part_stat_unlock(); |
| dm_disk(md)->part0.in_flight[rw] = atomic_inc_return(&md->pending[rw]); |
| } |
| |
| static void end_io_acct(struct dm_io *io) |
| { |
| struct mapped_device *md = io->md; |
| struct bio *bio = io->bio; |
| unsigned long duration = jiffies - io->start_time; |
| int pending, cpu; |
| int rw = bio_data_dir(bio); |
| |
| cpu = part_stat_lock(); |
| part_round_stats(cpu, &dm_disk(md)->part0); |
| part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration); |
| part_stat_unlock(); |
| |
| /* |
| * After this is decremented the bio must not be touched if it is |
| * a barrier. |
| */ |
| dm_disk(md)->part0.in_flight[rw] = pending = |
| atomic_dec_return(&md->pending[rw]); |
| 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) |
| { |
| down_write(&md->io_lock); |
| |
| spin_lock_irq(&md->deferred_lock); |
| bio_list_add(&md->deferred, bio); |
| spin_unlock_irq(&md->deferred_lock); |
| |
| if (!test_and_set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) |
| queue_work(md->wq, &md->work); |
| |
| up_write(&md->io_lock); |
| } |
| |
| /* |
| * Everyone (including functions in this file), should use this |
| * function to access the md->map field, and make sure they call |
| * dm_table_put() when finished. |
| */ |
| struct dm_table *dm_get_live_table(struct mapped_device *md) |
| { |
| struct dm_table *t; |
| unsigned long flags; |
| |
| read_lock_irqsave(&md->map_lock, flags); |
| t = md->map; |
| if (t) |
| dm_table_get(t); |
| read_unlock_irqrestore(&md->map_lock, flags); |
| |
| return t; |
| } |
| |
| /* |
| * Get the geometry associated with a dm device |
| */ |
| int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo) |
| { |
| *geo = md->geometry; |
| |
| return 0; |
| } |
| |
| /* |
| * Set the geometry of a device. |
| */ |
| int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo) |
| { |
| sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors; |
| |
| if (geo->start > sz) { |
| DMWARN("Start sector is beyond the geometry limits."); |
| return -EINVAL; |
| } |
| |
| md->geometry = *geo; |
| |
| return 0; |
| } |
| |
| /*----------------------------------------------------------------- |
| * CRUD START: |
| * A more elegant soln is in the works that uses the queue |
| * merge fn, unfortunately there are a couple of changes to |
| * the block layer that I want to make for this. So in the |
| * interests of getting something for people to use I give |
| * you this clearly demarcated crap. |
| *---------------------------------------------------------------*/ |
| |
| static int __noflush_suspending(struct mapped_device *md) |
| { |
| return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); |
| } |
| |
| /* |
| * Decrements the number of outstanding ios that a bio has been |
| * cloned into, completing the original io if necc. |
| */ |
| static void dec_pending(struct dm_io *io, int error) |
| { |
| unsigned long flags; |
| int io_error; |
| struct bio *bio; |
| struct mapped_device *md = io->md; |
| |
| /* Push-back supersedes any I/O errors */ |
| if (unlikely(error)) { |
| spin_lock_irqsave(&io->endio_lock, flags); |
| if (!(io->error > 0 && __noflush_suspending(md))) |
| io->error = error; |
| spin_unlock_irqrestore(&io->endio_lock, flags); |
| } |
| |
| if (atomic_dec_and_test(&io->io_count)) { |
| if (io->error == DM_ENDIO_REQUEUE) { |
| /* |
| * Target requested pushing back the I/O. |
| */ |
| spin_lock_irqsave(&md->deferred_lock, flags); |
| if (__noflush_suspending(md)) { |
| if (!(io->bio->bi_rw & REQ_HARDBARRIER)) |
| 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; |
| |
| if (bio->bi_rw & REQ_HARDBARRIER) { |
| /* |
| * There can be just one barrier request so we use |
| * a per-device variable for error reporting. |
| * Note that you can't touch the bio after end_io_acct |
| * |
| * We ignore -EOPNOTSUPP for empty flush reported by |
| * underlying devices. We assume that if the device |
| * doesn't support empty barriers, it doesn't need |
| * cache flushing commands. |
| */ |
| if (!md->barrier_error && |
| !(bio_empty_barrier(bio) && io_error == -EOPNOTSUPP)) |
| md->barrier_error = io_error; |
| end_io_acct(io); |
| free_io(md, io); |
| } else { |
| end_io_acct(io); |
| free_io(md, io); |
| |
| if (io_error != DM_ENDIO_REQUEUE) { |
| trace_block_bio_complete(md->queue, bio); |
| |
| bio_endio(bio, io_error); |
| } |
| } |
| } |
| } |
| |
| static void clone_endio(struct bio *bio, int error) |
| { |
| int r = 0; |
| struct dm_target_io *tio = bio->bi_private; |
| struct dm_io *io = tio->io; |
| struct mapped_device *md = tio->io->md; |
| dm_endio_fn endio = tio->ti->type->end_io; |
| |
| if (!bio_flagged(bio, BIO_UPTODATE) && !error) |
| error = -EIO; |
| |
| if (endio) { |
| r = endio(tio->ti, bio, error, &tio->info); |
| if (r < 0 || r == DM_ENDIO_REQUEUE) |
| /* |
| * error and requeue request are handled |
| * in dec_pending(). |
| */ |
| error = r; |
| else if (r == DM_ENDIO_INCOMPLETE) |
| /* The target will handle the io */ |
| return; |
| else if (r) { |
| DMWARN("unimplemented target endio return value: %d", r); |
| BUG(); |
| } |
| } |
| |
| /* |
| * Store md for cleanup instead of tio which is about to get freed. |
| */ |
| bio->bi_private = md->bs; |
| |
| free_tio(md, tio); |
| bio_put(bio); |
| dec_pending(io, error); |
| } |
| |
| /* |
| * Partial completion handling for request-based dm |
| */ |
| static void end_clone_bio(struct bio *clone, int error) |
| { |
| struct dm_rq_clone_bio_info *info = clone->bi_private; |
| struct dm_rq_target_io *tio = info->tio; |
| struct bio *bio = info->orig; |
| unsigned int nr_bytes = info->orig->bi_size; |
| |
| bio_put(clone); |
| |
| if (tio->error) |
| /* |
| * An error has already been detected on the request. |
| * Once error occurred, just let clone->end_io() handle |
| * the remainder. |
| */ |
| return; |
| else if (error) { |
| /* |
| * Don't notice the error to the upper layer yet. |
| * The error handling decision is made by the target driver, |
| * when the request is completed. |
| */ |
| tio->error = error; |
| return; |
| } |
| |
| /* |
| * I/O for the bio successfully completed. |
| * Notice the data completion to the upper layer. |
| */ |
| |
| /* |
| * bios are processed from the head of the list. |
| * So the completing bio should always be rq->bio. |
| * If it's not, something wrong is happening. |
| */ |
| if (tio->orig->bio != bio) |
| DMERR("bio completion is going in the middle of the request"); |
| |
| /* |
| * Update the original request. |
| * Do not use blk_end_request() here, because it may complete |
| * the original request before the clone, and break the ordering. |
| */ |
| blk_update_request(tio->orig, 0, nr_bytes); |
| } |
| |
| static void store_barrier_error(struct mapped_device *md, int error) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&md->barrier_error_lock, flags); |
| /* |
| * Basically, the first error is taken, but: |
| * -EOPNOTSUPP supersedes any I/O error. |
| * Requeue request supersedes any I/O error but -EOPNOTSUPP. |
| */ |
| if (!md->barrier_error || error == -EOPNOTSUPP || |
| (md->barrier_error != -EOPNOTSUPP && |
| error == DM_ENDIO_REQUEUE)) |
| md->barrier_error = error; |
| spin_unlock_irqrestore(&md->barrier_error_lock, flags); |
| } |
| |
| /* |
| * Don't touch any member of the md after calling this function because |
| * the md may be freed in dm_put() at the end of this function. |
| * Or do dm_get() before calling this function and dm_put() later. |
| */ |
| static void rq_completed(struct mapped_device *md, int rw, int run_queue) |
| { |
| atomic_dec(&md->pending[rw]); |
| |
| /* nudge anyone waiting on suspend queue */ |
| if (!md_in_flight(md)) |
| wake_up(&md->wait); |
| |
| if (run_queue) |
| blk_run_queue(md->queue); |
| |
| /* |
| * dm_put() must be at the end of this function. See the comment above |
| */ |
| dm_put(md); |
| } |
| |
| static void free_rq_clone(struct request *clone) |
| { |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| |
| blk_rq_unprep_clone(clone); |
| free_rq_tio(tio); |
| } |
| |
| /* |
| * Complete the clone and the original request. |
| * Must be called without queue lock. |
| */ |
| static void dm_end_request(struct request *clone, int error) |
| { |
| int rw = rq_data_dir(clone); |
| int run_queue = 1; |
| bool is_barrier = clone->cmd_flags & REQ_HARDBARRIER; |
| 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 && !is_barrier) { |
| 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); |
| |
| if (unlikely(is_barrier)) { |
| if (unlikely(error)) |
| store_barrier_error(md, error); |
| run_queue = 0; |
| } else |
| blk_end_request_all(rq, error); |
| |
| rq_completed(md, rw, run_queue); |
| } |
| |
| static void dm_unprep_request(struct request *rq) |
| { |
| struct request *clone = rq->special; |
| |
| rq->special = NULL; |
| rq->cmd_flags &= ~REQ_DONTPREP; |
| |
| free_rq_clone(clone); |
| } |
| |
| /* |
| * Requeue the original request of a clone. |
| */ |
| void dm_requeue_unmapped_request(struct request *clone) |
| { |
| int rw = rq_data_dir(clone); |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| struct mapped_device *md = tio->md; |
| struct request *rq = tio->orig; |
| struct request_queue *q = rq->q; |
| unsigned long flags; |
| |
| if (unlikely(clone->cmd_flags & REQ_HARDBARRIER)) { |
| /* |
| * Barrier clones share an original request. |
| * Leave it to dm_end_request(), which handles this special |
| * case. |
| */ |
| dm_end_request(clone, DM_ENDIO_REQUEUE); |
| return; |
| } |
| |
| dm_unprep_request(rq); |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| if (elv_queue_empty(q)) |
| blk_plug_device(q); |
| blk_requeue_request(q, rq); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| rq_completed(md, rw, 0); |
| } |
| EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request); |
| |
| static void __stop_queue(struct request_queue *q) |
| { |
| blk_stop_queue(q); |
| } |
| |
| static void stop_queue(struct request_queue *q) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| __stop_queue(q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| } |
| |
| static void __start_queue(struct request_queue *q) |
| { |
| if (blk_queue_stopped(q)) |
| blk_start_queue(q); |
| } |
| |
| static void start_queue(struct request_queue *q) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| __start_queue(q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| } |
| |
| static void dm_done(struct request *clone, int error, bool mapped) |
| { |
| int r = error; |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| dm_request_endio_fn rq_end_io = tio->ti->type->rq_end_io; |
| |
| if (mapped && rq_end_io) |
| r = rq_end_io(tio->ti, clone, error, &tio->info); |
| |
| if (r <= 0) |
| /* The target wants to complete the I/O */ |
| dm_end_request(clone, r); |
| else if (r == DM_ENDIO_INCOMPLETE) |
| /* The target will handle the I/O */ |
| return; |
| else if (r == DM_ENDIO_REQUEUE) |
| /* The target wants to requeue the I/O */ |
| dm_requeue_unmapped_request(clone); |
| else { |
| DMWARN("unimplemented target endio return value: %d", r); |
| BUG(); |
| } |
| } |
| |
| /* |
| * Request completion handler for request-based dm |
| */ |
| static void dm_softirq_done(struct request *rq) |
| { |
| bool mapped = true; |
| struct request *clone = rq->completion_data; |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| |
| if (rq->cmd_flags & REQ_FAILED) |
| mapped = false; |
| |
| dm_done(clone, tio->error, mapped); |
| } |
| |
| /* |
| * Complete the clone and the original request with the error status |
| * through softirq context. |
| */ |
| static void dm_complete_request(struct request *clone, int error) |
| { |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| struct request *rq = tio->orig; |
| |
| if (unlikely(clone->cmd_flags & REQ_HARDBARRIER)) { |
| /* |
| * Barrier clones share an original request. So can't use |
| * softirq_done with the original. |
| * Pass the clone to dm_done() directly in this special case. |
| * It is safe (even if clone->q->queue_lock is held here) |
| * because there is no I/O dispatching during the completion |
| * of barrier clone. |
| */ |
| dm_done(clone, error, true); |
| return; |
| } |
| |
| tio->error = error; |
| rq->completion_data = clone; |
| blk_complete_request(rq); |
| } |
| |
| /* |
| * Complete the not-mapped clone and the original request with the error status |
| * through softirq context. |
| * Target's rq_end_io() function isn't called. |
| * This may be used when the target's map_rq() function fails. |
| */ |
| void dm_kill_unmapped_request(struct request *clone, int error) |
| { |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| struct request *rq = tio->orig; |
| |
| if (unlikely(clone->cmd_flags & REQ_HARDBARRIER)) { |
| /* |
| * Barrier clones share an original request. |
| * Leave it to dm_end_request(), which handles this special |
| * case. |
| */ |
| BUG_ON(error > 0); |
| dm_end_request(clone, error); |
| return; |
| } |
| |
| rq->cmd_flags |= REQ_FAILED; |
| dm_complete_request(clone, error); |
| } |
| EXPORT_SYMBOL_GPL(dm_kill_unmapped_request); |
| |
| /* |
| * Called with the queue lock held |
| */ |
| static void end_clone_request(struct request *clone, int error) |
| { |
| /* |
| * For just cleaning up the information of the queue in which |
| * the clone was dispatched. |
| * The clone is *NOT* freed actually here because it is alloced from |
| * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags. |
| */ |
| __blk_put_request(clone->q, clone); |
| |
| /* |
| * Actual request completion is done in a softirq context which doesn't |
| * hold the queue lock. Otherwise, deadlock could occur because: |
| * - another request may be submitted by the upper level driver |
| * of the stacking during the completion |
| * - the submission which requires queue lock may be done |
| * against this queue |
| */ |
| dm_complete_request(clone, error); |
| } |
| |
| static sector_t max_io_len(struct mapped_device *md, |
| sector_t sector, struct dm_target *ti) |
| { |
| sector_t offset = sector - ti->begin; |
| sector_t len = ti->len - offset; |
| |
| /* |
| * Does the target need to split even further ? |
| */ |
| if (ti->split_io) { |
| sector_t boundary; |
| boundary = ((offset + ti->split_io) & ~(ti->split_io - 1)) |
| - offset; |
| if (len > boundary) |
| len = boundary; |
| } |
| |
| return len; |
| } |
| |
| static void __map_bio(struct dm_target *ti, struct bio *clone, |
| struct dm_target_io *tio) |
| { |
| int r; |
| sector_t sector; |
| struct mapped_device *md; |
| |
| clone->bi_end_io = clone_endio; |
| clone->bi_private = tio; |
| |
| /* |
| * Map the clone. If r == 0 we don't need to do |
| * anything, the target has assumed ownership of |
| * this io. |
| */ |
| atomic_inc(&tio->io->io_count); |
| sector = clone->bi_sector; |
| r = ti->type->map(ti, clone, &tio->info); |
| if (r == DM_MAPIO_REMAPPED) { |
| /* the bio has been remapped so dispatch it */ |
| |
| trace_block_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); |
| /* |
| * Store bio_set for cleanup. |
| */ |
| clone->bi_private = md->bs; |
| bio_put(clone); |
| free_tio(md, tio); |
| } else if (r) { |
| DMWARN("unimplemented target map return value: %d", r); |
| BUG(); |
| } |
| } |
| |
| struct clone_info { |
| struct mapped_device *md; |
| struct dm_table *map; |
| struct bio *bio; |
| struct dm_io *io; |
| sector_t sector; |
| sector_t sector_count; |
| unsigned short idx; |
| }; |
| |
| static void dm_bio_destructor(struct bio *bio) |
| { |
| struct bio_set *bs = bio->bi_private; |
| |
| bio_free(bio, bs); |
| } |
| |
| /* |
| * Creates a little bio that is just does part of a bvec. |
| */ |
| static struct bio *split_bvec(struct bio *bio, sector_t sector, |
| unsigned short idx, unsigned int offset, |
| unsigned int len, struct bio_set *bs) |
| { |
| struct bio *clone; |
| struct bio_vec *bv = bio->bi_io_vec + idx; |
| |
| clone = bio_alloc_bioset(GFP_NOIO, 1, bs); |
| clone->bi_destructor = dm_bio_destructor; |
| *clone->bi_io_vec = *bv; |
| |
| clone->bi_sector = sector; |
| clone->bi_bdev = bio->bi_bdev; |
| clone->bi_rw = bio->bi_rw & ~REQ_HARDBARRIER; |
| clone->bi_vcnt = 1; |
| clone->bi_size = to_bytes(len); |
| clone->bi_io_vec->bv_offset = offset; |
| clone->bi_io_vec->bv_len = clone->bi_size; |
| clone->bi_flags |= 1 << BIO_CLONED; |
| |
| if (bio_integrity(bio)) { |
| bio_integrity_clone(clone, bio, GFP_NOIO, bs); |
| bio_integrity_trim(clone, |
| bio_sector_offset(bio, idx, offset), len); |
| } |
| |
| return clone; |
| } |
| |
| /* |
| * Creates a bio that consists of range of complete bvecs. |
| */ |
| static struct bio *clone_bio(struct bio *bio, sector_t sector, |
| unsigned short idx, unsigned short bv_count, |
| unsigned int len, struct bio_set *bs) |
| { |
| struct bio *clone; |
| |
| clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs); |
| __bio_clone(clone, bio); |
| clone->bi_rw &= ~REQ_HARDBARRIER; |
| clone->bi_destructor = dm_bio_destructor; |
| clone->bi_sector = sector; |
| clone->bi_idx = idx; |
| clone->bi_vcnt = idx + bv_count; |
| clone->bi_size = to_bytes(len); |
| clone->bi_flags &= ~(1 << BIO_SEG_VALID); |
| |
| if (bio_integrity(bio)) { |
| bio_integrity_clone(clone, bio, GFP_NOIO, bs); |
| |
| if (idx != bio->bi_idx || clone->bi_size < bio->bi_size) |
| bio_integrity_trim(clone, |
| bio_sector_offset(bio, idx, 0), len); |
| } |
| |
| return clone; |
| } |
| |
| static struct dm_target_io *alloc_tio(struct clone_info *ci, |
| struct dm_target *ti) |
| { |
| struct dm_target_io *tio = mempool_alloc(ci->md->tio_pool, GFP_NOIO); |
| |
| tio->io = ci->io; |
| tio->ti = ti; |
| memset(&tio->info, 0, sizeof(tio->info)); |
| |
| return tio; |
| } |
| |
| static void __flush_target(struct clone_info *ci, struct dm_target *ti, |
| unsigned request_nr) |
| { |
| struct dm_target_io *tio = alloc_tio(ci, ti); |
| struct bio *clone; |
| |
| tio->info.target_request_nr = request_nr; |
| |
| clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs); |
| __bio_clone(clone, ci->bio); |
| clone->bi_destructor = dm_bio_destructor; |
| |
| __map_bio(ti, clone, tio); |
| } |
| |
| static int __clone_and_map_empty_barrier(struct clone_info *ci) |
| { |
| unsigned target_nr = 0, request_nr; |
| struct dm_target *ti; |
| |
| while ((ti = dm_table_get_target(ci->map, target_nr++))) |
| for (request_nr = 0; request_nr < ti->num_flush_requests; |
| request_nr++) |
| __flush_target(ci, ti, request_nr); |
| |
| ci->sector_count = 0; |
| |
| return 0; |
| } |
| |
| static int __clone_and_map(struct clone_info *ci) |
| { |
| struct bio *clone, *bio = ci->bio; |
| struct dm_target *ti; |
| sector_t len = 0, max; |
| struct dm_target_io *tio; |
| |
| if (unlikely(bio_empty_barrier(bio))) |
| return __clone_and_map_empty_barrier(ci); |
| |
| ti = dm_table_find_target(ci->map, ci->sector); |
| if (!dm_target_is_valid(ti)) |
| return -EIO; |
| |
| max = max_io_len(ci->md, ci->sector, ti); |
| |
| /* |
| * Allocate a target io object. |
| */ |
| tio = alloc_tio(ci, ti); |
| |
| if (ci->sector_count <= max) { |
| /* |
| * Optimise for the simple case where we can do all of |
| * the remaining io with a single clone. |
| */ |
| clone = clone_bio(bio, ci->sector, ci->idx, |
| bio->bi_vcnt - ci->idx, ci->sector_count, |
| ci->md->bs); |
| __map_bio(ti, clone, tio); |
| ci->sector_count = 0; |
| |
| } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { |
| /* |
| * There are some bvecs that don't span targets. |
| * Do as many of these as possible. |
| */ |
| int i; |
| sector_t remaining = max; |
| sector_t bv_len; |
| |
| for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) { |
| bv_len = to_sector(bio->bi_io_vec[i].bv_len); |
| |
| if (bv_len > remaining) |
| break; |
| |
| remaining -= bv_len; |
| len += bv_len; |
| } |
| |
| clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len, |
| ci->md->bs); |
| __map_bio(ti, clone, tio); |
| |
| ci->sector += len; |
| ci->sector_count -= len; |
| ci->idx = i; |
| |
| } else { |
| /* |
| * Handle a bvec that must be split between two or more targets. |
| */ |
| struct bio_vec *bv = bio->bi_io_vec + ci->idx; |
| sector_t remaining = to_sector(bv->bv_len); |
| unsigned int offset = 0; |
| |
| do { |
| if (offset) { |
| ti = dm_table_find_target(ci->map, ci->sector); |
| if (!dm_target_is_valid(ti)) |
| return -EIO; |
| |
| max = max_io_len(ci->md, ci->sector, ti); |
| |
| tio = alloc_tio(ci, ti); |
| } |
| |
| len = min(remaining, max); |
| |
| clone = split_bvec(bio, ci->sector, ci->idx, |
| bv->bv_offset + offset, len, |
| ci->md->bs); |
| |
| __map_bio(ti, clone, tio); |
| |
| ci->sector += len; |
| ci->sector_count -= len; |
| offset += to_bytes(len); |
| } while (remaining -= len); |
| |
| ci->idx++; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Split the bio into several clones and submit it to targets. |
| */ |
| static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) |
| { |
| struct clone_info ci; |
| int error = 0; |
| |
| ci.map = dm_get_live_table(md); |
| if (unlikely(!ci.map)) { |
| if (!(bio->bi_rw & REQ_HARDBARRIER)) |
| bio_io_error(bio); |
| else |
| if (!md->barrier_error) |
| md->barrier_error = -EIO; |
| return; |
| } |
| |
| ci.md = md; |
| ci.bio = bio; |
| ci.io = alloc_io(md); |
| ci.io->error = 0; |
| atomic_set(&ci.io->io_count, 1); |
| ci.io->bio = bio; |
| ci.io->md = md; |
| spin_lock_init(&ci.io->endio_lock); |
| ci.sector = bio->bi_sector; |
| ci.sector_count = bio_sectors(bio); |
| if (unlikely(bio_empty_barrier(bio))) |
| ci.sector_count = 1; |
| ci.idx = bio->bi_idx; |
| |
| start_io_acct(ci.io); |
| while (ci.sector_count && !error) |
| error = __clone_and_map(&ci); |
| |
| /* drop the extra reference count */ |
| dec_pending(ci.io, error); |
| dm_table_put(ci.map); |
| } |
| /*----------------------------------------------------------------- |
| * CRUD END |
| *---------------------------------------------------------------*/ |
| |
| static int dm_merge_bvec(struct request_queue *q, |
| struct bvec_merge_data *bvm, |
| struct bio_vec *biovec) |
| { |
| struct mapped_device *md = q->queuedata; |
| struct dm_table *map = dm_get_live_table(md); |
| struct dm_target *ti; |
| sector_t max_sectors; |
| int max_size = 0; |
| |
| if (unlikely(!map)) |
| goto out; |
| |
| ti = dm_table_find_target(map, bvm->bi_sector); |
| if (!dm_target_is_valid(ti)) |
| goto out_table; |
| |
| /* |
| * Find maximum amount of I/O that won't need splitting |
| */ |
| max_sectors = min(max_io_len(md, bvm->bi_sector, ti), |
| (sector_t) BIO_MAX_SECTORS); |
| max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size; |
| if (max_size < 0) |
| max_size = 0; |
| |
| /* |
| * merge_bvec_fn() returns number of bytes |
| * it can accept at this offset |
| * max is precomputed maximal io size |
| */ |
| if (max_size && ti->type->merge) |
| max_size = ti->type->merge(ti, bvm, biovec, max_size); |
| /* |
| * If the target doesn't support merge method and some of the devices |
| * provided their merge_bvec method (we know this by looking at |
| * queue_max_hw_sectors), then we can't allow bios with multiple vector |
| * entries. So always set max_size to 0, and the code below allows |
| * just one page. |
| */ |
| else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9) |
| |
| max_size = 0; |
| |
| out_table: |
| dm_table_put(map); |
| |
| out: |
| /* |
| * Always allow an entire first page |
| */ |
| if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT)) |
| max_size = biovec->bv_len; |
| |
| return max_size; |
| } |
| |
| /* |
| * The request function that just remaps the bio built up by |
| * dm_merge_bvec. |
| */ |
| static int _dm_request(struct request_queue *q, struct bio *bio) |
| { |
| int rw = bio_data_dir(bio); |
| struct mapped_device *md = q->queuedata; |
| int cpu; |
| |
| down_read(&md->io_lock); |
| |
| cpu = part_stat_lock(); |
| part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]); |
| part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio)); |
| part_stat_unlock(); |
| |
| /* |
| * If we're suspended or the thread is processing barriers |
| * we have to queue this io for later. |
| */ |
| if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) || |
| unlikely(bio->bi_rw & REQ_HARDBARRIER)) { |
| up_read(&md->io_lock); |
| |
| if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) && |
| bio_rw(bio) == READA) { |
| bio_io_error(bio); |
| return 0; |
| } |
| |
| queue_io(md, bio); |
| |
| return 0; |
| } |
| |
| __split_and_process_bio(md, bio); |
| up_read(&md->io_lock); |
| return 0; |
| } |
| |
| static int dm_make_request(struct request_queue *q, struct bio *bio) |
| { |
| struct mapped_device *md = q->queuedata; |
| |
| return md->saved_make_request_fn(q, bio); /* call __make_request() */ |
| } |
| |
| static int dm_request_based(struct mapped_device *md) |
| { |
| return blk_queue_stackable(md->queue); |
| } |
| |
| static int dm_request(struct request_queue *q, struct bio *bio) |
| { |
| struct mapped_device *md = q->queuedata; |
| |
| if (dm_request_based(md)) |
| return dm_make_request(q, bio); |
| |
| return _dm_request(q, bio); |
| } |
| |
| static bool dm_rq_is_flush_request(struct request *rq) |
| { |
| if (rq->cmd_flags & REQ_FLUSH) |
| return true; |
| else |
| return false; |
| } |
| |
| void dm_dispatch_request(struct request *rq) |
| { |
| int r; |
| |
| if (blk_queue_io_stat(rq->q)) |
| rq->cmd_flags |= REQ_IO_STAT; |
| |
| rq->start_time = jiffies; |
| r = blk_insert_cloned_request(rq->q, rq); |
| if (r) |
| dm_complete_request(rq, r); |
| } |
| EXPORT_SYMBOL_GPL(dm_dispatch_request); |
| |
| static void dm_rq_bio_destructor(struct bio *bio) |
| { |
| struct dm_rq_clone_bio_info *info = bio->bi_private; |
| struct mapped_device *md = info->tio->md; |
| |
| free_bio_info(info); |
| bio_free(bio, md->bs); |
| } |
| |
| static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig, |
| void *data) |
| { |
| struct dm_rq_target_io *tio = data; |
| struct mapped_device *md = tio->md; |
| struct dm_rq_clone_bio_info *info = alloc_bio_info(md); |
| |
| if (!info) |
| return -ENOMEM; |
| |
| info->orig = bio_orig; |
| info->tio = tio; |
| bio->bi_end_io = end_clone_bio; |
| bio->bi_private = info; |
| bio->bi_destructor = dm_rq_bio_destructor; |
| |
| return 0; |
| } |
| |
| static int setup_clone(struct request *clone, struct request *rq, |
| struct dm_rq_target_io *tio) |
| { |
| int r; |
| |
| if (dm_rq_is_flush_request(rq)) { |
| blk_rq_init(NULL, clone); |
| clone->cmd_type = REQ_TYPE_FS; |
| clone->cmd_flags |= (REQ_HARDBARRIER | WRITE); |
| } else { |
| r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC, |
| dm_rq_bio_constructor, tio); |
| if (r) |
| return r; |
| |
| clone->cmd = rq->cmd; |
| clone->cmd_len = rq->cmd_len; |
| clone->sense = rq->sense; |
| clone->buffer = rq->buffer; |
| } |
| |
| clone->end_io = end_clone_request; |
| clone->end_io_data = tio; |
| |
| return 0; |
| } |
| |
| static struct request *clone_rq(struct request *rq, struct mapped_device *md, |
| gfp_t gfp_mask) |
| { |
| struct request *clone; |
| struct dm_rq_target_io *tio; |
| |
| tio = alloc_rq_tio(md, gfp_mask); |
| if (!tio) |
| return NULL; |
| |
| tio->md = md; |
| tio->ti = NULL; |
| tio->orig = rq; |
| tio->error = 0; |
| memset(&tio->info, 0, sizeof(tio->info)); |
| |
| clone = &tio->clone; |
| if (setup_clone(clone, rq, tio)) { |
| /* -ENOMEM */ |
| free_rq_tio(tio); |
| return NULL; |
| } |
| |
| return clone; |
| } |
| |
| /* |
| * Called with the queue lock held. |
| */ |
| static int dm_prep_fn(struct request_queue *q, struct request *rq) |
| { |
| struct mapped_device *md = q->queuedata; |
| struct request *clone; |
| |
| if (unlikely(dm_rq_is_flush_request(rq))) |
| return BLKPREP_OK; |
| |
| if (unlikely(rq->special)) { |
| DMWARN("Already has something in rq->special."); |
| return BLKPREP_KILL; |
| } |
| |
| clone = clone_rq(rq, md, GFP_ATOMIC); |
| if (!clone) |
| return BLKPREP_DEFER; |
| |
| rq->special = clone; |
| rq->cmd_flags |= REQ_DONTPREP; |
| |
| return BLKPREP_OK; |
| } |
| |
| /* |
| * Returns: |
| * 0 : the request has been processed (not requeued) |
| * !0 : the request has been requeued |
| */ |
| static int map_request(struct dm_target *ti, struct request *clone, |
| struct mapped_device *md) |
| { |
| int r, requeued = 0; |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| |
| /* |
| * Hold the md reference here for the in-flight I/O. |
| * We can't rely on the reference count by device opener, |
| * because the device may be closed during the request completion |
| * when all bios are completed. |
| * See the comment in rq_completed() too. |
| */ |
| dm_get(md); |
| |
| tio->ti = ti; |
| r = ti->type->map_rq(ti, clone, &tio->info); |
| switch (r) { |
| case DM_MAPIO_SUBMITTED: |
| /* The target has taken the I/O to submit by itself later */ |
| break; |
| case DM_MAPIO_REMAPPED: |
| /* The target has remapped the I/O so dispatch it */ |
| trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)), |
| blk_rq_pos(tio->orig)); |
| dm_dispatch_request(clone); |
| break; |
| case DM_MAPIO_REQUEUE: |
| /* The target wants to requeue the I/O */ |
| dm_requeue_unmapped_request(clone); |
| requeued = 1; |
| break; |
| default: |
| if (r > 0) { |
| DMWARN("unimplemented target map return value: %d", r); |
| BUG(); |
| } |
| |
| /* The target wants to complete the I/O */ |
| dm_kill_unmapped_request(clone, r); |
| break; |
| } |
| |
| return requeued; |
| } |
| |
| /* |
| * q->request_fn for request-based dm. |
| * Called with the queue lock held. |
| */ |
| static void dm_request_fn(struct request_queue *q) |
| { |
| struct mapped_device *md = q->queuedata; |
| struct dm_table *map = dm_get_live_table(md); |
| struct dm_target *ti; |
| struct request *rq, *clone; |
| |
| /* |
| * 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_plugged(q) && !blk_queue_stopped(q)) { |
| rq = blk_peek_request(q); |
| if (!rq) |
| goto plug_and_out; |
| |
| if (unlikely(dm_rq_is_flush_request(rq))) { |
| BUG_ON(md->flush_request); |
| md->flush_request = rq; |
| blk_start_request(rq); |
| queue_work(md->wq, &md->barrier_work); |
| goto out; |
| } |
| |
| ti = dm_table_find_target(map, blk_rq_pos(rq)); |
| if (ti->type->busy && ti->type->busy(ti)) |
| goto plug_and_out; |
| |
| blk_start_request(rq); |
| clone = rq->special; |
| atomic_inc(&md->pending[rq_data_dir(clone)]); |
| |
| spin_unlock(q->queue_lock); |
| if (map_request(ti, clone, md)) |
| goto requeued; |
| |
| spin_lock_irq(q->queue_lock); |
| } |
| |
| goto out; |
| |
| requeued: |
| spin_lock_irq(q->queue_lock); |
| |
| plug_and_out: |
| if (!elv_queue_empty(q)) |
| /* Some requests still remain, retry later */ |
| blk_plug_device(q); |
| |
| out: |
| dm_table_put(map); |
| |
| return; |
| } |
| |
| int dm_underlying_device_busy(struct request_queue *q) |
| { |
| return blk_lld_busy(q); |
| } |
| EXPORT_SYMBOL_GPL(dm_underlying_device_busy); |
| |
| static int dm_lld_busy(struct request_queue *q) |
| { |
| int r; |
| struct mapped_device *md = q->queuedata; |
| struct dm_table *map = dm_get_live_table(md); |
| |
| if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) |
| r = 1; |
| else |
| r = dm_table_any_busy_target(map); |
| |
| dm_table_put(map); |
| |
| return r; |
| } |
| |
| static void dm_unplug_all(struct request_queue *q) |
| { |
| struct mapped_device *md = q->queuedata; |
| struct dm_table *map = dm_get_live_table(md); |
| |
| if (map) { |
| if (dm_request_based(md)) |
| generic_unplug_device(q); |
| |
| dm_table_unplug_all(map); |
| dm_table_put(map); |
| } |
| } |
| |
| static int dm_any_congested(void *congested_data, int bdi_bits) |
| { |
| int r = bdi_bits; |
| struct mapped_device *md = congested_data; |
| struct dm_table *map; |
| |
| if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { |
| map = dm_get_live_table(md); |
| if (map) { |
| /* |
| * Request-based dm cares about only own queue for |
| * the query about congestion status of request_queue |
| */ |
| if (dm_request_based(md)) |
| r = md->queue->backing_dev_info.state & |
| bdi_bits; |
| else |
| r = dm_table_any_congested(map, bdi_bits); |
| |
| dm_table_put(map); |
| } |
| } |
| |
| return r; |
| } |
| |
| /*----------------------------------------------------------------- |
| * An IDR is used to keep track of allocated minor numbers. |
| *---------------------------------------------------------------*/ |
| static DEFINE_IDR(_minor_idr); |
| |
| static void free_minor(int minor) |
| { |
| spin_lock(&_minor_lock); |
| idr_remove(&_minor_idr, minor); |
| spin_unlock(&_minor_lock); |
| } |
| |
| /* |
| * See if the device with a specific minor # is free. |
| */ |
| static int specific_minor(int minor) |
| { |
| int r, m; |
| |
| if (minor >= (1 << MINORBITS)) |
| return -EINVAL; |
| |
| r = idr_pre_get(&_minor_idr, GFP_KERNEL); |
| if (!r) |
| return -ENOMEM; |
| |
| spin_lock(&_minor_lock); |
| |
| if (idr_find(&_minor_idr, minor)) { |
| r = -EBUSY; |
| goto out; |
| } |
| |
| r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m); |
| if (r) |
| goto out; |
| |
| if (m != minor) { |
| idr_remove(&_minor_idr, m); |
| r = -EBUSY; |
| goto out; |
| } |
| |
| out: |
| spin_unlock(&_minor_lock); |
| return r; |
| } |
| |
| static int next_free_minor(int *minor) |
| { |
| int r, m; |
| |
| r = idr_pre_get(&_minor_idr, GFP_KERNEL); |
| if (!r) |
| return -ENOMEM; |
| |
| spin_lock(&_minor_lock); |
| |
| r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m); |
| if (r) |
| goto out; |
| |
| if (m >= (1 << MINORBITS)) { |
| idr_remove(&_minor_idr, m); |
| r = -ENOSPC; |
| goto out; |
| } |
| |
| *minor = m; |
| |
| out: |
| spin_unlock(&_minor_lock); |
| return r; |
| } |
| |
| static const struct block_device_operations dm_blk_dops; |
| |
| static void dm_wq_work(struct work_struct *work); |
| static void dm_rq_barrier_work(struct work_struct *work); |
| |
| static void dm_init_md_queue(struct mapped_device *md) |
| { |
| /* |
| * Request-based dm devices cannot be stacked on top of bio-based dm |
| * devices. The type of this dm device has not been decided yet. |
| * The type is decided at the first table loading time. |
| * To prevent problematic device stacking, clear the queue flag |
| * for request stacking support until then. |
| * |
| * This queue is new, so no concurrency on the queue_flags. |
| */ |
| queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue); |
| |
| md->queue->queuedata = md; |
| md->queue->backing_dev_info.congested_fn = dm_any_congested; |
| md->queue->backing_dev_info.congested_data = md; |
| blk_queue_make_request(md->queue, dm_request); |
| blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); |
| md->queue->unplug_fn = dm_unplug_all; |
| blk_queue_merge_bvec(md->queue, dm_merge_bvec); |
| } |
| |
| /* |
| * Allocate and initialise a blank device with a given minor. |
| */ |
| static struct mapped_device *alloc_dev(int minor) |
| { |
| int r; |
| struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL); |
| void *old_md; |
| |
| if (!md) { |
| DMWARN("unable to allocate device, out of memory."); |
| return NULL; |
| } |
| |
| if (!try_module_get(THIS_MODULE)) |
| goto bad_module_get; |
| |
| /* get a minor number for the dev */ |
| if (minor == DM_ANY_MINOR) |
| r = next_free_minor(&minor); |
| else |
| r = specific_minor(minor); |
| if (r < 0) |
| goto bad_minor; |
| |
| md->type = DM_TYPE_NONE; |
| init_rwsem(&md->io_lock); |
| mutex_init(&md->suspend_lock); |
| mutex_init(&md->type_lock); |
| spin_lock_init(&md->deferred_lock); |
| spin_lock_init(&md->barrier_error_lock); |
| rwlock_init(&md->map_lock); |
| atomic_set(&md->holders, 1); |
| atomic_set(&md->open_count, 0); |
| atomic_set(&md->event_nr, 0); |
| atomic_set(&md->uevent_seq, 0); |
| INIT_LIST_HEAD(&md->uevent_list); |
| spin_lock_init(&md->uevent_lock); |
| |
| md->queue = blk_alloc_queue(GFP_KERNEL); |
| if (!md->queue) |
| goto bad_queue; |
| |
| dm_init_md_queue(md); |
| |
| md->disk = alloc_disk(1); |
| if (!md->disk) |
| goto bad_disk; |
| |
| atomic_set(&md->pending[0], 0); |
| atomic_set(&md->pending[1], 0); |
| init_waitqueue_head(&md->wait); |
| INIT_WORK(&md->work, dm_wq_work); |
| INIT_WORK(&md->barrier_work, dm_rq_barrier_work); |
| init_waitqueue_head(&md->eventq); |
| |
| md->disk->major = _major; |
| md->disk->first_minor = minor; |
| md->disk->fops = &dm_blk_dops; |
| md->disk->queue = md->queue; |
| md->disk->private_data = md; |
| sprintf(md->disk->disk_name, "dm-%d", minor); |
| add_disk(md->disk); |
| format_dev_t(md->name, MKDEV(_major, minor)); |
| |
| md->wq = create_singlethread_workqueue("kdmflush"); |
| if (!md->wq) |
| goto bad_thread; |
| |
| md->bdev = bdget_disk(md->disk, 0); |
| if (!md->bdev) |
| goto bad_bdev; |
| |
| /* Populate the mapping, nobody knows we exist yet */ |
| spin_lock(&_minor_lock); |
| old_md = idr_replace(&_minor_idr, md, minor); |
| spin_unlock(&_minor_lock); |
| |
| BUG_ON(old_md != MINOR_ALLOCED); |
| |
| return md; |
| |
| bad_bdev: |
| destroy_workqueue(md->wq); |
| bad_thread: |
| del_gendisk(md->disk); |
| put_disk(md->disk); |
| bad_disk: |
| blk_cleanup_queue(md->queue); |
| bad_queue: |
| free_minor(minor); |
| bad_minor: |
| module_put(THIS_MODULE); |
| bad_module_get: |
| kfree(md); |
| return NULL; |
| } |
| |
| static void unlock_fs(struct mapped_device *md); |
| |
| static void free_dev(struct mapped_device *md) |
| { |
| int minor = MINOR(disk_devt(md->disk)); |
| |
| unlock_fs(md); |
| bdput(md->bdev); |
| destroy_workqueue(md->wq); |
| if (md->tio_pool) |
| mempool_destroy(md->tio_pool); |
| if (md->io_pool) |
| mempool_destroy(md->io_pool); |
| if (md->bs) |
| bioset_free(md->bs); |
| blk_integrity_unregister(md->disk); |
| del_gendisk(md->disk); |
| free_minor(minor); |
| |
| spin_lock(&_minor_lock); |
| md->disk->private_data = NULL; |
| spin_unlock(&_minor_lock); |
| |
| put_disk(md->disk); |
| blk_cleanup_queue(md->queue); |
| module_put(THIS_MODULE); |
| kfree(md); |
| } |
| |
| static void __bind_mempools(struct mapped_device *md, struct dm_table *t) |
| { |
| struct dm_md_mempools *p; |
| |
| if (md->io_pool && md->tio_pool && md->bs) |
| /* the md already has necessary mempools */ |
| goto out; |
| |
| p = dm_table_get_md_mempools(t); |
| BUG_ON(!p || md->io_pool || md->tio_pool || md->bs); |
| |
| md->io_pool = p->io_pool; |
| p->io_pool = NULL; |
| md->tio_pool = p->tio_pool; |
| p->tio_pool = NULL; |
| md->bs = p->bs; |
| p->bs = NULL; |
| |
| out: |
| /* mempool bind completed, now no need any mempools in the table */ |
| dm_table_free_md_mempools(t); |
| } |
| |
| /* |
| * Bind a table to the device. |
| */ |
| static void event_callback(void *context) |
| { |
| unsigned long flags; |
| LIST_HEAD(uevents); |
| struct mapped_device *md = (struct mapped_device *) context; |
| |
| spin_lock_irqsave(&md->uevent_lock, flags); |
| list_splice_init(&md->uevent_list, &uevents); |
| spin_unlock_irqrestore(&md->uevent_lock, flags); |
| |
| dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj); |
| |
| atomic_inc(&md->event_nr); |
| wake_up(&md->eventq); |
| } |
| |
| static void __set_size(struct mapped_device *md, sector_t size) |
| { |
| set_capacity(md->disk, size); |
| |
| mutex_lock(&md->bdev->bd_inode->i_mutex); |
| i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT); |
| mutex_unlock(&md->bdev->bd_inode->i_mutex); |
| } |
| |
| /* |
| * Returns old map, which caller must destroy. |
| */ |
| static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t, |
| struct queue_limits *limits) |
| { |
| struct dm_table *old_map; |
| struct request_queue *q = md->queue; |
| sector_t size; |
| unsigned long flags; |
| |
| size = dm_table_get_size(t); |
| |
| /* |
| * Wipe any geometry if the size of the table changed. |
| */ |
| if (size != get_capacity(md->disk)) |
| memset(&md->geometry, 0, sizeof(md->geometry)); |
| |
| __set_size(md, size); |
| |
| dm_table_event_callback(t, event_callback, md); |
| |
| /* |
| * The queue hasn't been stopped yet, if the old table type wasn't |
| * for request-based during suspension. So stop it to prevent |
| * I/O mapping before resume. |
| * This must be done before setting the queue restrictions, |
| * because request-based dm may be run just after the setting. |
| */ |
| if (dm_table_request_based(t) && !blk_queue_stopped(q)) |
| stop_queue(q); |
| |
| __bind_mempools(md, t); |
| |
| write_lock_irqsave(&md->map_lock, flags); |
| old_map = md->map; |
| md->map = t; |
| dm_table_set_restrictions(t, q, limits); |
| write_unlock_irqrestore(&md->map_lock, flags); |
| |
| return old_map; |
| } |
| |
| /* |
| * Returns unbound table for the caller to free. |
| */ |
| static struct dm_table *__unbind(struct mapped_device *md) |
| { |
| struct dm_table *map = md->map; |
| unsigned long flags; |
| |
| if (!map) |
| return NULL; |
| |
| dm_table_event_callback(map, NULL, NULL); |
| write_lock_irqsave(&md->map_lock, flags); |
| md->map = NULL; |
| write_unlock_irqrestore(&md->map_lock, flags); |
| |
| return map; |
| } |
| |
| /* |
| * Constructor for a new device. |
| */ |
| int dm_create(int minor, struct mapped_device **result) |
| { |
| struct mapped_device *md; |
| |
| md = alloc_dev(minor); |
| if (!md) |
| return -ENXIO; |
| |
| dm_sysfs_init(md); |
| |
| *result = md; |
| return 0; |
| } |
| |
| /* |
| * Functions to manage md->type. |
| * All are required to hold md->type_lock. |
| */ |
| void dm_lock_md_type(struct mapped_device *md) |
| { |
| mutex_lock(&md->type_lock); |
| } |
| |
| void dm_unlock_md_type(struct mapped_device *md) |
| { |
| mutex_unlock(&md->type_lock); |
| } |
| |
| void dm_set_md_type(struct mapped_device *md, unsigned type) |
| { |
| md->type = type; |
| } |
| |
| unsigned dm_get_md_type(struct mapped_device *md) |
| { |
| return md->type; |
| } |
| |
| /* |
| * Fully initialize a request-based queue (->elevator, ->request_fn, etc). |
| */ |
| static int dm_init_request_based_queue(struct mapped_device *md) |
| { |
| struct request_queue *q = NULL; |
| |
| if (md->queue->elevator) |
| return 1; |
| |
| /* Fully initialize the queue */ |
| q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL); |
| if (!q) |
| return 0; |
| |
| md->queue = q; |
| md->saved_make_request_fn = md->queue->make_request_fn; |
| dm_init_md_queue(md); |
| blk_queue_softirq_done(md->queue, dm_softirq_done); |
| blk_queue_prep_rq(md->queue, dm_prep_fn); |
| blk_queue_lld_busy(md->queue, dm_lld_busy); |
| blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN_FLUSH); |
| |
| elv_register_queue(md->queue); |
| |
| return 1; |
| } |
| |
| /* |
| * Setup the DM device's queue based on md's type |
| */ |
| int dm_setup_md_queue(struct mapped_device *md) |
| { |
| if ((dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) && |
| !dm_init_request_based_queue(md)) { |
| DMWARN("Cannot initialize queue for request-based mapped device"); |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| static struct mapped_device *dm_find_md(dev_t dev) |
| { |
| struct mapped_device *md; |
| unsigned minor = MINOR(dev); |
| |
| if (MAJOR(dev) != _major || minor >= (1 << MINORBITS)) |
| return NULL; |
| |
| spin_lock(&_minor_lock); |
| |
| md = idr_find(&_minor_idr, minor); |
| if (md && (md == MINOR_ALLOCED || |
| (MINOR(disk_devt(dm_disk(md))) != minor) || |
| dm_deleting_md(md) || |
| test_bit(DMF_FREEING, &md->flags))) { |
| md = NULL; |
| goto out; |
| } |
| |
| out: |
| spin_unlock(&_minor_lock); |
| |
| return md; |
| } |
| |
| struct mapped_device *dm_get_md(dev_t dev) |
| { |
| struct mapped_device *md = dm_find_md(dev); |
| |
| if (md) |
| dm_get(md); |
| |
| return md; |
| } |
| |
| void *dm_get_mdptr(struct mapped_device *md) |
| { |
| return md->interface_ptr; |
| } |
| |
| void dm_set_mdptr(struct mapped_device *md, void *ptr) |
| { |
| md->interface_ptr = ptr; |
| } |
| |
| void dm_get(struct mapped_device *md) |
| { |
| atomic_inc(&md->holders); |
| BUG_ON(test_bit(DMF_FREEING, &md->flags)); |
| } |
| |
| const char *dm_device_name(struct mapped_device *md) |
| { |
| return md->name; |
| } |
| EXPORT_SYMBOL_GPL(dm_device_name); |
| |
| static void __dm_destroy(struct mapped_device *md, bool wait) |
| { |
| struct dm_table *map; |
| |
| might_sleep(); |
| |
| spin_lock(&_minor_lock); |
| map = dm_get_live_table(md); |
| idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md)))); |
| set_bit(DMF_FREEING, &md->flags); |
| spin_unlock(&_minor_lock); |
| |
| if (!dm_suspended_md(md)) { |
| dm_table_presuspend_targets(map); |
| dm_table_postsuspend_targets(map); |
| } |
| |
| /* |
| * Rare, but there may be I/O requests still going to complete, |
| * for example. Wait for all references to disappear. |
| * No one should increment the reference count of the mapped_device, |
| * after the mapped_device state becomes DMF_FREEING. |
| */ |
| if (wait) |
| while (atomic_read(&md->holders)) |
| msleep(1); |
| else if (atomic_read(&md->holders)) |
| DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)", |
| dm_device_name(md), atomic_read(&md->holders)); |
| |
| dm_sysfs_exit(md); |
| dm_table_put(map); |
| dm_table_destroy(__unbind(md)); |
| free_dev(md); |
| } |
| |
| void dm_destroy(struct mapped_device *md) |
| { |
| __dm_destroy(md, true); |
| } |
| |
| void dm_destroy_immediate(struct mapped_device *md) |
| { |
| __dm_destroy(md, false); |
| } |
| |
| void dm_put(struct mapped_device *md) |
| { |
| atomic_dec(&md->holders); |
| } |
| EXPORT_SYMBOL_GPL(dm_put); |
| |
| static int dm_wait_for_completion(struct mapped_device *md, int interruptible) |
| { |
| int r = 0; |
| DECLARE_WAITQUEUE(wait, current); |
| |
| dm_unplug_all(md->queue); |
| |
| add_wait_queue(&md->wait, &wait); |
| |
| while (1) { |
| set_current_state(interruptible); |
| |
| smp_mb(); |
| 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; |
| } |
| |
| static void dm_flush(struct mapped_device *md) |
| { |
| dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE); |
| |
| bio_init(&md->barrier_bio); |
| md->barrier_bio.bi_bdev = md->bdev; |
| md->barrier_bio.bi_rw = WRITE_BARRIER; |
| __split_and_process_bio(md, &md->barrier_bio); |
| |
| dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE); |
| } |
| |
| static void process_barrier(struct mapped_device *md, struct bio *bio) |
| { |
| md->barrier_error = 0; |
| |
| dm_flush(md); |
| |
| if (!bio_empty_barrier(bio)) { |
| __split_and_process_bio(md, bio); |
| /* |
| * If the request isn't supported, don't waste time with |
| * the second flush. |
| */ |
| if (md->barrier_error != -EOPNOTSUPP) |
| dm_flush(md); |
| } |
| |
| if (md->barrier_error != DM_ENDIO_REQUEUE) |
| bio_endio(bio, md->barrier_error); |
| else { |
| spin_lock_irq(&md->deferred_lock); |
| bio_list_add_head(&md->deferred, bio); |
| spin_unlock_irq(&md->deferred_lock); |
| } |
| } |
| |
| /* |
| * Process the deferred bios |
| */ |
| static void dm_wq_work(struct work_struct *work) |
| { |
| struct mapped_device *md = container_of(work, struct mapped_device, |
| work); |
| struct bio *c; |
| |
| down_write(&md->io_lock); |
| |
| while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { |
| spin_lock_irq(&md->deferred_lock); |
| c = bio_list_pop(&md->deferred); |
| spin_unlock_irq(&md->deferred_lock); |
| |
| if (!c) { |
| clear_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags); |
| break; |
| } |
| |
| up_write(&md->io_lock); |
| |
| if (dm_request_based(md)) |
| generic_make_request(c); |
| else { |
| if (c->bi_rw & REQ_HARDBARRIER) |
| process_barrier(md, c); |
| else |
| __split_and_process_bio(md, c); |
| } |
| |
| down_write(&md->io_lock); |
| } |
| |
| up_write(&md->io_lock); |
| } |
| |
| static void dm_queue_flush(struct mapped_device *md) |
| { |
| clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); |
| smp_mb__after_clear_bit(); |
| queue_work(md->wq, &md->work); |
| } |
| |
| static void dm_rq_set_target_request_nr(struct request *clone, unsigned request_nr) |
| { |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| |
| tio->info.target_request_nr = request_nr; |
| } |
| |
| /* Issue barrier requests to targets and wait for their completion. */ |
| static int dm_rq_barrier(struct mapped_device *md) |
| { |
| int i, j; |
| struct dm_table *map = dm_get_live_table(md); |
| unsigned num_targets = dm_table_get_num_targets(map); |
| struct dm_target *ti; |
| struct request *clone; |
| |
| md->barrier_error = 0; |
| |
| for (i = 0; i < num_targets; i++) { |
| ti = dm_table_get_target(map, i); |
| for (j = 0; j < ti->num_flush_requests; j++) { |
| clone = clone_rq(md->flush_request, md, GFP_NOIO); |
| dm_rq_set_target_request_nr(clone, j); |
| atomic_inc(&md->pending[rq_data_dir(clone)]); |
| map_request(ti, clone, md); |
| } |
| } |
| |
| dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE); |
| dm_table_put(map); |
| |
| return md->barrier_error; |
| } |
| |
| static void dm_rq_barrier_work(struct work_struct *work) |
| { |
| int error; |
| struct mapped_device *md = container_of(work, struct mapped_device, |
| barrier_work); |
| struct request_queue *q = md->queue; |
| struct request *rq; |
| unsigned long flags; |
| |
| /* |
| * Hold the md reference here and leave it at the last part so that |
| * the md can't be deleted by device opener when the barrier request |
| * completes. |
| */ |
| dm_get(md); |
| |
| error = dm_rq_barrier(md); |
| |
| rq = md->flush_request; |
| md->flush_request = NULL; |
| |
| if (error == DM_ENDIO_REQUEUE) { |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_requeue_request(q, rq); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| } else |
| blk_end_request_all(rq, error); |
| |
| blk_run_queue(q); |
| |
| dm_put(md); |
| } |
| |
| /* |
| * Swap in a new table, returning the old one for the caller to destroy. |
| */ |
| struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table) |
| { |
| struct dm_table *map = ERR_PTR(-EINVAL); |
| struct queue_limits limits; |
| int r; |
| |
| mutex_lock(&md->suspend_lock); |
| |
| /* device must be suspended */ |
| if (!dm_suspended_md(md)) |
| goto out; |
| |
| r = dm_calculate_queue_limits(table, &limits); |
| if (r) { |
| map = ERR_PTR(r); |
| goto out; |
| } |
| |
| map = __bind(md, table, &limits); |
| |
| out: |
| mutex_unlock(&md->suspend_lock); |
| return map; |
| } |
| |
| /* |
| * Functions to lock and unlock any filesystem running on the |
| * device. |
| */ |
| static int lock_fs(struct mapped_device *md) |
| { |
| int r; |
| |
| WARN_ON(md->frozen_sb); |
| |
| md->frozen_sb = freeze_bdev(md->bdev); |
| if (IS_ERR(md->frozen_sb)) { |
| r = PTR_ERR(md->frozen_sb); |
| md->frozen_sb = NULL; |
| return r; |
| } |
| |
| set_bit(DMF_FROZEN, &md->flags); |
| |
| return 0; |
| } |
| |
| static void unlock_fs(struct mapped_device *md) |
| { |
| if (!test_bit(DMF_FROZEN, &md->flags)) |
| return; |
| |
| thaw_bdev(md->bdev, md->frozen_sb); |
| md->frozen_sb = NULL; |
| clear_bit(DMF_FROZEN, &md->flags); |
| } |
| |
| /* |
| * We need to be able to change a mapping table under a mounted |
| * filesystem. For example we might want to move some data in |
| * the background. Before the table can be swapped with |
| * dm_bind_table, dm_suspend must be called to flush any in |
| * flight bios and ensure that any further io gets deferred. |
| */ |
| /* |
| * Suspend mechanism in request-based dm. |
| * |
| * 1. Flush all I/Os by lock_fs() if needed. |
| * 2. Stop dispatching any I/O by stopping the request_queue. |
| * 3. Wait for all in-flight I/Os to be completed or requeued. |
| * |
| * To abort suspend, start the request_queue. |
| */ |
| int dm_suspend(struct mapped_device *md, unsigned suspend_flags) |
| { |
| struct dm_table *map = NULL; |
| int r = 0; |
| int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0; |
| int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0; |
| |
| mutex_lock(&md->suspend_lock); |
| |
| if (dm_suspended_md(md)) { |
| r = -EINVAL; |
| goto out_unlock; |
| } |
| |
| map = dm_get_live_table(md); |
| |
| /* |
| * DMF_NOFLUSH_SUSPENDING must be set before presuspend. |
| * This flag is cleared before dm_suspend returns. |
| */ |
| if (noflush) |
| set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); |
| |
| /* This does not get reverted if there's an error later. */ |
| dm_table_presuspend_targets(map); |
| |
| /* |
| * Flush I/O to the device. |
| * Any I/O submitted after lock_fs() may not be flushed. |
| * noflush takes precedence over do_lockfs. |
| * (lock_fs() flushes I/Os and waits for them to complete.) |
| */ |
| if (!noflush && do_lockfs) { |
| r = lock_fs(md); |
| if (r) |
| goto out; |
| } |
| |
| /* |
| * Here we must make sure that no processes are submitting requests |
| * to target drivers i.e. no one may be executing |
| * __split_and_process_bio. This is called from dm_request and |
| * dm_wq_work. |
| * |
| * To get all processes out of __split_and_process_bio in dm_request, |
| * we take the write lock. To prevent any process from reentering |
| * __split_and_process_bio from dm_request, we set |
| * DMF_QUEUE_IO_TO_THREAD. |
| * |
| * To quiesce the thread (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND |
| * and call flush_workqueue(md->wq). flush_workqueue will wait until |
| * dm_wq_work exits and DMF_BLOCK_IO_FOR_SUSPEND will prevent any |
| * further calls to __split_and_process_bio from dm_wq_work. |
| */ |
| down_write(&md->io_lock); |
| set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); |
| set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags); |
| up_write(&md->io_lock); |
| |
| /* |
| * Request-based dm uses md->wq for barrier (dm_rq_barrier_work) which |
| * can be kicked until md->queue is stopped. So stop md->queue before |
| * flushing md->wq. |
| */ |
| if (dm_request_based(md)) |
| stop_queue(md->queue); |
| |
| flush_workqueue(md->wq); |
| |
| /* |
| * At this point no more requests are entering target request routines. |
| * We call dm_wait_for_completion to wait for all existing requests |
| * to finish. |
| */ |
| r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE); |
| |
| down_write(&md->io_lock); |
| if (noflush) |
| clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); |
| up_write(&md->io_lock); |
| |
| /* were we interrupted ? */ |
| if (r < 0) { |
| dm_queue_flush(md); |
| |
| if (dm_request_based(md)) |
| start_queue(md->queue); |
| |
| unlock_fs(md); |
| goto out; /* pushback list is already flushed, so skip flush */ |
| } |
| |
| /* |
| * If dm_wait_for_completion returned 0, the device is completely |
| * quiescent now. There is no request-processing activity. All new |
| * requests are being added to md->deferred list. |
| */ |
| |
| set_bit(DMF_SUSPENDED, &md->flags); |
| |
| dm_table_postsuspend_targets(map); |
| |
| out: |
| dm_table_put(map); |
| |
| out_unlock: |
| mutex_unlock(&md->suspend_lock); |
| return r; |
| } |
| |
| int dm_resume(struct mapped_device *md) |
| { |
| int r = -EINVAL; |
| struct dm_table *map = NULL; |
| |
| mutex_lock(&md->suspend_lock); |
| if (!dm_suspended_md(md)) |
| goto out; |
| |
| map = dm_get_live_table(md); |
| if (!map || !dm_table_get_size(map)) |
| goto out; |
| |
| r = dm_table_resume_targets(map); |
| if (r) |
| goto out; |
| |
| dm_queue_flush(md); |
| |
| /* |
| * Flushing deferred I/Os must be done after targets are resumed |
| * so that mapping of targets can work correctly. |
| * Request-based dm is queueing the deferred I/Os in its request_queue. |
| */ |
| if (dm_request_based(md)) |
| start_queue(md->queue); |
| |
| unlock_fs(md); |
| |
| clear_bit(DMF_SUSPENDED, &md->flags); |
| |
| dm_table_unplug_all(map); |
| r = 0; |
| out: |
| dm_table_put(map); |
| mutex_unlock(&md->suspend_lock); |
| |
| return r; |
| } |
| |
| /*----------------------------------------------------------------- |
| * Event notification. |
| *---------------------------------------------------------------*/ |
| int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action, |
| unsigned cookie) |
| { |
| char udev_cookie[DM_COOKIE_LENGTH]; |
| char *envp[] = { udev_cookie, NULL }; |
| |
| if (!cookie) |
| return kobject_uevent(&disk_to_dev(md->disk)->kobj, action); |
| else { |
| snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u", |
| DM_COOKIE_ENV_VAR_NAME, cookie); |
| return kobject_uevent_env(&disk_to_dev(md->disk)->kobj, |
| action, envp); |
| } |
| } |
| |
| uint32_t dm_next_uevent_seq(struct mapped_device *md) |
| { |
| return atomic_add_return(1, &md->uevent_seq); |
| } |
| |
| uint32_t dm_get_event_nr(struct mapped_device *md) |
| { |
| return atomic_read(&md->event_nr); |
| } |
| |
| int dm_wait_event(struct mapped_device *md, int event_nr) |
| { |
| return wait_event_interruptible(md->eventq, |
| (event_nr != atomic_read(&md->event_nr))); |
| } |
| |
| void dm_uevent_add(struct mapped_device *md, struct list_head *elist) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&md->uevent_lock, flags); |
| list_add(elist, &md->uevent_list); |
| spin_unlock_irqrestore(&md->uevent_lock, flags); |
| } |
| |
| /* |
| * The gendisk is only valid as long as you have a reference |
| * count on 'md'. |
| */ |
| struct gendisk *dm_disk(struct mapped_device *md) |
| { |
| return md->disk; |
| } |
| |
| struct kobject *dm_kobject(struct mapped_device *md) |
| { |
| return &md->kobj; |
| } |
| |
| /* |
| * struct mapped_device should not be exported outside of dm.c |
| * so use this check to verify that kobj is part of md structure |
| */ |
| struct mapped_device *dm_get_from_kobject(struct kobject *kobj) |
| { |
| struct mapped_device *md; |
| |
| md = container_of(kobj, struct mapped_device, kobj); |
| if (&md->kobj != kobj) |
| return NULL; |
| |
| if (test_bit(DMF_FREEING, &md->flags) || |
| dm_deleting_md(md)) |
| return NULL; |
| |
| dm_get(md); |
| return md; |
| } |
| |
| int dm_suspended_md(struct mapped_device *md) |
| { |
| return test_bit(DMF_SUSPENDED, &md->flags); |
| } |
| |
| int dm_suspended(struct dm_target *ti) |
| { |
| return dm_suspended_md(dm_table_get_md(ti->table)); |
| } |
| EXPORT_SYMBOL_GPL(dm_suspended); |
| |
| int dm_noflush_suspending(struct dm_target *ti) |
| { |
| return __noflush_suspending(dm_table_get_md(ti->table)); |
| } |
| EXPORT_SYMBOL_GPL(dm_noflush_suspending); |
| |
| struct dm_md_mempools *dm_alloc_md_mempools(unsigned type) |
| { |
| struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL); |
| |
| if (!pools) |
| return NULL; |
| |
| pools->io_pool = (type == DM_TYPE_BIO_BASED) ? |
| mempool_create_slab_pool(MIN_IOS, _io_cache) : |
| mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache); |
| if (!pools->io_pool) |
| goto free_pools_and_out; |
| |
| pools->tio_pool = (type == DM_TYPE_BIO_BASED) ? |
| mempool_create_slab_pool(MIN_IOS, _tio_cache) : |
| mempool_create_slab_pool(MIN_IOS, _rq_tio_cache); |
| if (!pools->tio_pool) |
| goto free_io_pool_and_out; |
| |
| pools->bs = (type == DM_TYPE_BIO_BASED) ? |
| bioset_create(16, 0) : bioset_create(MIN_IOS, 0); |
| if (!pools->bs) |
| goto free_tio_pool_and_out; |
| |
| return pools; |
| |
| free_tio_pool_and_out: |
| mempool_destroy(pools->tio_pool); |
| |
| free_io_pool_and_out: |
| mempool_destroy(pools->io_pool); |
| |
| free_pools_and_out: |
| kfree(pools); |
| |
| return NULL; |
| } |
| |
| void dm_free_md_mempools(struct dm_md_mempools *pools) |
| { |
| if (!pools) |
| return; |
| |
| if (pools->io_pool) |
| mempool_destroy(pools->io_pool); |
| |
| if (pools->tio_pool) |
| mempool_destroy(pools->tio_pool); |
| |
| if (pools->bs) |
| bioset_free(pools->bs); |
| |
| kfree(pools); |
| } |
| |
| static const struct block_device_operations dm_blk_dops = { |
| .open = dm_blk_open, |
| .release = dm_blk_close, |
| .ioctl = dm_blk_ioctl, |
| .getgeo = dm_blk_getgeo, |
| .owner = THIS_MODULE |
| }; |
| |
| EXPORT_SYMBOL(dm_get_mapinfo); |
| |
| /* |
| * module hooks |
| */ |
| module_init(dm_init); |
| module_exit(dm_exit); |
| |
| module_param(major, uint, 0); |
| MODULE_PARM_DESC(major, "The major number of the device mapper"); |
| MODULE_DESCRIPTION(DM_NAME " driver"); |
| MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); |
| MODULE_LICENSE("GPL"); |