diff options
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 374 |
1 files changed, 270 insertions, 104 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index d21e1284604f..ac384b2a6a33 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -15,10 +15,12 @@ #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> @@ -123,6 +125,10 @@ struct mapped_device { 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]; @@ -338,6 +344,7 @@ 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; @@ -355,6 +362,7 @@ static int dm_blk_open(struct block_device *bdev, fmode_t mode) out: spin_unlock(&_minor_lock); + unlock_kernel(); return md ? 0 : -ENXIO; } @@ -362,8 +370,12 @@ out: 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; } @@ -614,7 +626,7 @@ static void dec_pending(struct dm_io *io, int error) */ spin_lock_irqsave(&md->deferred_lock, flags); if (__noflush_suspending(md)) { - if (!bio_rw_flagged(io->bio, BIO_RW_BARRIER)) + if (!(io->bio->bi_rw & REQ_HARDBARRIER)) bio_list_add_head(&md->deferred, io->bio); } else @@ -626,13 +638,19 @@ static void dec_pending(struct dm_io *io, int error) io_error = io->error; bio = io->bio; - if (bio_rw_flagged(bio, BIO_RW_BARRIER)) { + 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 && io_error != -EOPNOTSUPP) + if (!md->barrier_error && + !(bio_empty_barrier(bio) && io_error == -EOPNOTSUPP)) md->barrier_error = io_error; end_io_acct(io); free_io(md, io); @@ -792,12 +810,12 @@ static void dm_end_request(struct request *clone, int error) { int rw = rq_data_dir(clone); int run_queue = 1; - bool is_barrier = blk_barrier_rq(clone); + 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 (blk_pc_request(rq) && !is_barrier) { + if (rq->cmd_type == REQ_TYPE_BLOCK_PC && !is_barrier) { rq->errors = clone->errors; rq->resid_len = clone->resid_len; @@ -844,7 +862,7 @@ void dm_requeue_unmapped_request(struct request *clone) struct request_queue *q = rq->q; unsigned long flags; - if (unlikely(blk_barrier_rq(clone))) { + if (unlikely(clone->cmd_flags & REQ_HARDBARRIER)) { /* * Barrier clones share an original request. * Leave it to dm_end_request(), which handles this special @@ -943,7 +961,7 @@ 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(blk_barrier_rq(clone))) { + if (unlikely(clone->cmd_flags & REQ_HARDBARRIER)) { /* * Barrier clones share an original request. So can't use * softirq_done with the original. @@ -972,7 +990,7 @@ 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(blk_barrier_rq(clone))) { + if (unlikely(clone->cmd_flags & REQ_HARDBARRIER)) { /* * Barrier clones share an original request. * Leave it to dm_end_request(), which handles this special @@ -1012,17 +1030,27 @@ static void end_clone_request(struct request *clone, int error) dm_complete_request(clone, error); } -static sector_t max_io_len(struct mapped_device *md, - sector_t sector, struct dm_target *ti) +/* + * Return maximum size of I/O possible at the supplied sector up to the current + * target boundary. + */ +static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti) { - sector_t offset = sector - ti->begin; - sector_t len = ti->len - offset; + sector_t target_offset = dm_target_offset(ti, sector); + + return ti->len - target_offset; +} + +static sector_t max_io_len(sector_t sector, struct dm_target *ti) +{ + sector_t len = max_io_len_target_boundary(sector, ti); /* * Does the target need to split even further ? */ if (ti->split_io) { sector_t boundary; + sector_t offset = dm_target_offset(ti, sector); boundary = ((offset + ti->split_io) & ~(ti->split_io - 1)) - offset; if (len > boundary) @@ -1106,7 +1134,7 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector, clone->bi_sector = sector; clone->bi_bdev = bio->bi_bdev; - clone->bi_rw = bio->bi_rw & ~(1 << BIO_RW_BARRIER); + 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; @@ -1133,7 +1161,7 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector, clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs); __bio_clone(clone, bio); - clone->bi_rw &= ~(1 << BIO_RW_BARRIER); + clone->bi_rw &= ~REQ_HARDBARRIER; clone->bi_destructor = dm_bio_destructor; clone->bi_sector = sector; clone->bi_idx = idx; @@ -1164,36 +1192,96 @@ static struct dm_target_io *alloc_tio(struct clone_info *ci, return tio; } -static void __flush_target(struct clone_info *ci, struct dm_target *ti, - unsigned flush_nr) +static void __issue_target_request(struct clone_info *ci, struct dm_target *ti, + unsigned request_nr, sector_t len) { struct dm_target_io *tio = alloc_tio(ci, ti); struct bio *clone; - tio->info.flush_request = flush_nr; + tio->info.target_request_nr = request_nr; - clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs); + /* + * Discard requests require the bio's inline iovecs be initialized. + * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush + * and discard, so no need for concern about wasted bvec allocations. + */ + clone = bio_alloc_bioset(GFP_NOIO, ci->bio->bi_max_vecs, ci->md->bs); __bio_clone(clone, ci->bio); clone->bi_destructor = dm_bio_destructor; + if (len) { + clone->bi_sector = ci->sector; + clone->bi_size = to_bytes(len); + } __map_bio(ti, clone, tio); } +static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti, + unsigned num_requests, sector_t len) +{ + unsigned request_nr; + + for (request_nr = 0; request_nr < num_requests; request_nr++) + __issue_target_request(ci, ti, request_nr, len); +} + static int __clone_and_map_empty_barrier(struct clone_info *ci) { - unsigned target_nr = 0, flush_nr; + unsigned target_nr = 0; struct dm_target *ti; while ((ti = dm_table_get_target(ci->map, target_nr++))) - for (flush_nr = 0; flush_nr < ti->num_flush_requests; - flush_nr++) - __flush_target(ci, ti, flush_nr); + __issue_target_requests(ci, ti, ti->num_flush_requests, 0); ci->sector_count = 0; return 0; } +/* + * Perform all io with a single clone. + */ +static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti) +{ + struct bio *clone, *bio = ci->bio; + struct dm_target_io *tio; + + tio = alloc_tio(ci, ti); + clone = clone_bio(bio, ci->sector, ci->idx, + bio->bi_vcnt - ci->idx, ci->sector_count, + ci->md->bs); + __map_bio(ti, clone, tio); + ci->sector_count = 0; +} + +static int __clone_and_map_discard(struct clone_info *ci) +{ + struct dm_target *ti; + sector_t len; + + do { + ti = dm_table_find_target(ci->map, ci->sector); + if (!dm_target_is_valid(ti)) + return -EIO; + + /* + * Even though the device advertised discard support, + * reconfiguration might have changed that since the + * check was performed. + */ + if (!ti->num_discard_requests) + return -EOPNOTSUPP; + + len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti)); + + __issue_target_requests(ci, ti, ti->num_discard_requests, len); + + ci->sector += len; + } while (ci->sector_count -= len); + + return 0; +} + static int __clone_and_map(struct clone_info *ci) { struct bio *clone, *bio = ci->bio; @@ -1204,27 +1292,21 @@ static int __clone_and_map(struct clone_info *ci) if (unlikely(bio_empty_barrier(bio))) return __clone_and_map_empty_barrier(ci); + if (unlikely(bio->bi_rw & REQ_DISCARD)) + return __clone_and_map_discard(ci); + ti = dm_table_find_target(ci->map, ci->sector); if (!dm_target_is_valid(ti)) return -EIO; - max = max_io_len(ci->md, ci->sector, ti); - - /* - * Allocate a target io object. - */ - tio = alloc_tio(ci, ti); + max = max_io_len(ci->sector, ti); if (ci->sector_count <= max) { /* * Optimise for the simple case where we can do all of * the remaining io with a single clone. */ - clone = 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; + __clone_and_map_simple(ci, ti); } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { /* @@ -1245,6 +1327,7 @@ static int __clone_and_map(struct clone_info *ci) len += bv_len; } + tio = alloc_tio(ci, ti); clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len, ci->md->bs); __map_bio(ti, clone, tio); @@ -1267,13 +1350,12 @@ static int __clone_and_map(struct clone_info *ci) if (!dm_target_is_valid(ti)) return -EIO; - max = max_io_len(ci->md, ci->sector, ti); - - tio = alloc_tio(ci, ti); + max = max_io_len(ci->sector, ti); } len = min(remaining, max); + tio = alloc_tio(ci, ti); clone = split_bvec(bio, ci->sector, ci->idx, bv->bv_offset + offset, len, ci->md->bs); @@ -1301,7 +1383,7 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) ci.map = dm_get_live_table(md); if (unlikely(!ci.map)) { - if (!bio_rw_flagged(bio, BIO_RW_BARRIER)) + if (!(bio->bi_rw & REQ_HARDBARRIER)) bio_io_error(bio); else if (!md->barrier_error) @@ -1355,7 +1437,7 @@ static int dm_merge_bvec(struct request_queue *q, /* * Find maximum amount of I/O that won't need splitting */ - max_sectors = min(max_io_len(md, bvm->bi_sector, ti), + max_sectors = min(max_io_len(bvm->bi_sector, ti), (sector_t) BIO_MAX_SECTORS); max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size; if (max_size < 0) @@ -1414,7 +1496,7 @@ static int _dm_request(struct request_queue *q, struct bio *bio) * we have to queue this io for later. */ if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) || - unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) { + unlikely(bio->bi_rw & REQ_HARDBARRIER)) { up_read(&md->io_lock); if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) && @@ -1455,20 +1537,9 @@ static int dm_request(struct request_queue *q, struct bio *bio) return _dm_request(q, bio); } -/* - * Mark this request as flush request, so that dm_request_fn() can - * recognize. - */ -static void dm_rq_prepare_flush(struct request_queue *q, struct request *rq) -{ - rq->cmd_type = REQ_TYPE_LINUX_BLOCK; - rq->cmd[0] = REQ_LB_OP_FLUSH; -} - static bool dm_rq_is_flush_request(struct request *rq) { - if (rq->cmd_type == REQ_TYPE_LINUX_BLOCK && - rq->cmd[0] == REQ_LB_OP_FLUSH) + if (rq->cmd_flags & REQ_FLUSH) return true; else return false; @@ -1849,6 +1920,28 @@ 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. */ @@ -1874,8 +1967,10 @@ static struct mapped_device *alloc_dev(int 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); @@ -1886,34 +1981,11 @@ static struct mapped_device *alloc_dev(int minor) INIT_LIST_HEAD(&md->uevent_list); spin_lock_init(&md->uevent_lock); - md->queue = blk_init_queue(dm_request_fn, NULL); + md->queue = blk_alloc_queue(GFP_KERNEL); if (!md->queue) goto bad_queue; - /* - * 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, - * although we initialized the queue using blk_init_queue(). - * 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->saved_make_request_fn = md->queue->make_request_fn; - 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); - 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, - dm_rq_prepare_flush); + dm_init_md_queue(md); md->disk = alloc_disk(1); if (!md->disk) @@ -2128,6 +2200,72 @@ int dm_create(int minor, struct mapped_device **result) 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; @@ -2141,6 +2279,7 @@ static struct mapped_device *dm_find_md(dev_t dev) 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; @@ -2175,6 +2314,7 @@ void dm_set_mdptr(struct mapped_device *md, void *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) @@ -2183,27 +2323,55 @@ const char *dm_device_name(struct mapped_device *md) } EXPORT_SYMBOL_GPL(dm_device_name); -void dm_put(struct mapped_device *md) +static void __dm_destroy(struct mapped_device *md, bool wait) { struct dm_table *map; - BUG_ON(test_bit(DMF_FREEING, &md->flags)); + might_sleep(); - if (atomic_dec_and_lock(&md->holders, &_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); - } - dm_sysfs_exit(md); - dm_table_put(map); - dm_table_destroy(__unbind(md)); - free_dev(md); + 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); @@ -2258,7 +2426,12 @@ static void process_barrier(struct mapped_device *md, struct bio *bio) if (!bio_empty_barrier(bio)) { __split_and_process_bio(md, bio); - dm_flush(md); + /* + * 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) @@ -2296,7 +2469,7 @@ static void dm_wq_work(struct work_struct *work) if (dm_request_based(md)) generic_make_request(c); else { - if (bio_rw_flagged(c, BIO_RW_BARRIER)) + if (c->bi_rw & REQ_HARDBARRIER) process_barrier(md, c); else __split_and_process_bio(md, c); @@ -2315,11 +2488,11 @@ static void dm_queue_flush(struct mapped_device *md) queue_work(md->wq, &md->work); } -static void dm_rq_set_flush_nr(struct request *clone, unsigned flush_nr) +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.flush_request = flush_nr; + tio->info.target_request_nr = request_nr; } /* Issue barrier requests to targets and wait for their completion. */ @@ -2337,7 +2510,7 @@ static int dm_rq_barrier(struct mapped_device *md) 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_flush_nr(clone, j); + dm_rq_set_target_request_nr(clone, j); atomic_inc(&md->pending[rq_data_dir(clone)]); map_request(ti, clone, md); } @@ -2403,13 +2576,6 @@ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table) goto out; } - /* cannot change the device type, once a table is bound */ - if (md->map && - (dm_table_get_type(md->map) != dm_table_get_type(table))) { - DMWARN("can't change the device type after a table is bound"); - goto out; - } - map = __bind(md, table, &limits); out: |
