diff options
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 1142 |
1 files changed, 1003 insertions, 139 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 424f7b048c3..3c6d4ee8921 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -19,11 +19,18 @@ #include <linux/slab.h> #include <linux/idr.h> #include <linux/hdreg.h> -#include <linux/blktrace_api.h> -#include <trace/block.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; @@ -53,8 +60,6 @@ struct dm_target_io { union map_info info; }; -DEFINE_TRACE(block_bio_complete); - /* * For request-based dm. * One of these is allocated per request. @@ -73,7 +78,7 @@ struct dm_rq_target_io { */ struct dm_rq_clone_bio_info { struct bio *orig; - struct request *rq; + struct dm_rq_target_io *tio; }; union map_info *dm_get_mapinfo(struct bio *bio) @@ -83,6 +88,14 @@ union map_info *dm_get_mapinfo(struct bio *bio) 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) /* @@ -159,13 +172,31 @@ struct mapped_device { * freeze/thaw support require holding onto a super block */ struct super_block *frozen_sb; - struct block_device *suspended_bdev; + struct block_device *bdev; /* forced geometry settings */ struct hd_geometry geometry; + /* marker of flush suspend for request-based dm */ + struct request suspend_rq; + + /* 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 @@ -393,14 +424,29 @@ static void free_io(struct mapped_device *md, struct dm_io *io) mempool_free(io, md->io_pool); } -static struct dm_target_io *alloc_tio(struct mapped_device *md) +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) { - return mempool_alloc(md->tio_pool, GFP_NOIO); + return mempool_alloc(md->tio_pool, GFP_ATOMIC); } -static void free_tio(struct mapped_device *md, struct dm_target_io *tio) +static void free_rq_tio(struct dm_rq_target_io *tio) { - mempool_free(tio, md->tio_pool); + 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 void start_io_acct(struct dm_io *io) @@ -466,12 +512,13 @@ static void queue_io(struct mapped_device *md, struct bio *bio) struct dm_table *dm_get_table(struct mapped_device *md) { struct dm_table *t; + unsigned long flags; - read_lock(&md->map_lock); + read_lock_irqsave(&md->map_lock, flags); t = md->map; if (t) dm_table_get(t); - read_unlock(&md->map_lock); + read_unlock_irqrestore(&md->map_lock, flags); return t; } @@ -538,9 +585,11 @@ static void dec_pending(struct dm_io *io, int error) * Target requested pushing back the I/O. */ spin_lock_irqsave(&md->deferred_lock, flags); - if (__noflush_suspending(md)) - bio_list_add_head(&md->deferred, io->bio); - else + if (__noflush_suspending(md)) { + if (!bio_barrier(io->bio)) + bio_list_add_head(&md->deferred, + io->bio); + } else /* noflush suspend was interrupted. */ io->error = -EIO; spin_unlock_irqrestore(&md->deferred_lock, flags); @@ -555,7 +604,8 @@ static void dec_pending(struct dm_io *io, int error) * a per-device variable for error reporting. * Note that you can't touch the bio after end_io_acct */ - md->barrier_error = io_error; + if (!md->barrier_error && io_error != -EOPNOTSUPP) + md->barrier_error = io_error; end_io_acct(io); } else { end_io_acct(io); @@ -609,6 +659,262 @@ static void clone_endio(struct bio *bio, int error) dec_pending(io, error); } +/* + * Partial completion handling for request-based dm + */ +static void end_clone_bio(struct bio *clone, int error) +{ + struct dm_rq_clone_bio_info *info = clone->bi_private; + struct dm_rq_target_io *tio = info->tio; + struct bio *bio = info->orig; + unsigned int nr_bytes = info->orig->bi_size; + + bio_put(clone); + + if (tio->error) + /* + * An error has already been detected on the request. + * Once error occurred, just let clone->end_io() handle + * the remainder. + */ + return; + else if (error) { + /* + * Don't notice the error to the upper layer yet. + * The error handling decision is made by the target driver, + * when the request is completed. + */ + tio->error = error; + return; + } + + /* + * I/O for the bio successfully completed. + * Notice the data completion to the upper layer. + */ + + /* + * bios are processed from the head of the list. + * So the completing bio should always be rq->bio. + * If it's not, something wrong is happening. + */ + if (tio->orig->bio != bio) + DMERR("bio completion is going in the middle of the request"); + + /* + * Update the original request. + * Do not use blk_end_request() here, because it may complete + * the original request before the clone, and break the ordering. + */ + blk_update_request(tio->orig, 0, nr_bytes); +} + +/* + * Don't touch any member of the md after calling this function because + * the md may be freed in dm_put() at the end of this function. + * Or do dm_get() before calling this function and dm_put() later. + */ +static void rq_completed(struct mapped_device *md, int run_queue) +{ + int wakeup_waiters = 0; + struct request_queue *q = md->queue; + unsigned long flags; + + spin_lock_irqsave(q->queue_lock, flags); + if (!queue_in_flight(q)) + wakeup_waiters = 1; + spin_unlock_irqrestore(q->queue_lock, flags); + + /* nudge anyone waiting on suspend queue */ + if (wakeup_waiters) + wake_up(&md->wait); + + if (run_queue) + blk_run_queue(q); + + /* + * dm_put() must be at the end of this function. See the comment above + */ + dm_put(md); +} + +static void dm_unprep_request(struct request *rq) +{ + struct request *clone = rq->special; + struct dm_rq_target_io *tio = clone->end_io_data; + + rq->special = NULL; + rq->cmd_flags &= ~REQ_DONTPREP; + + blk_rq_unprep_clone(clone); + free_rq_tio(tio); +} + +/* + * Requeue the original request of a clone. + */ +void dm_requeue_unmapped_request(struct request *clone) +{ + struct dm_rq_target_io *tio = clone->end_io_data; + struct mapped_device *md = tio->md; + struct request *rq = tio->orig; + struct request_queue *q = rq->q; + unsigned long flags; + + dm_unprep_request(rq); + + spin_lock_irqsave(q->queue_lock, flags); + if (elv_queue_empty(q)) + blk_plug_device(q); + blk_requeue_request(q, rq); + spin_unlock_irqrestore(q->queue_lock, flags); + + rq_completed(md, 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); +} + +/* + * Complete the clone and the original request. + * Must be called without queue lock. + */ +static void dm_end_request(struct request *clone, int error) +{ + 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)) { + 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; + } + + BUG_ON(clone->bio); + free_rq_tio(tio); + + blk_end_request_all(rq, error); + + rq_completed(md, 1); +} + +/* + * Request completion handler for request-based dm + */ +static void dm_softirq_done(struct request *rq) +{ + struct request *clone = rq->completion_data; + struct dm_rq_target_io *tio = clone->end_io_data; + dm_request_endio_fn rq_end_io = tio->ti->type->rq_end_io; + int error = tio->error; + + if (!(rq->cmd_flags & REQ_FAILED) && rq_end_io) + error = rq_end_io(tio->ti, clone, error, &tio->info); + + if (error <= 0) + /* The target wants to complete the I/O */ + dm_end_request(clone, error); + else if (error == DM_ENDIO_INCOMPLETE) + /* The target will handle the I/O */ + return; + else if (error == DM_ENDIO_REQUEUE) + /* The target wants to requeue the I/O */ + dm_requeue_unmapped_request(clone); + else { + DMWARN("unimplemented target endio return value: %d", error); + BUG(); + } +} + +/* + * Complete the clone and the original request with the error status + * through softirq context. + */ +static void dm_complete_request(struct request *clone, int error) +{ + struct dm_rq_target_io *tio = clone->end_io_data; + struct request *rq = tio->orig; + + tio->error = error; + rq->completion_data = clone; + blk_complete_request(rq); +} + +/* + * Complete the not-mapped clone and the original request with the error status + * through softirq context. + * Target's rq_end_io() function isn't called. + * This may be used when the target's map_rq() function fails. + */ +void dm_kill_unmapped_request(struct request *clone, int error) +{ + struct dm_rq_target_io *tio = clone->end_io_data; + struct request *rq = tio->orig; + + rq->cmd_flags |= REQ_FAILED; + dm_complete_request(clone, error); +} +EXPORT_SYMBOL_GPL(dm_kill_unmapped_request); + +/* + * Called with the queue lock held + */ +static void end_clone_request(struct request *clone, int error) +{ + /* + * For just cleaning up the information of the queue in which + * the clone was dispatched. + * The clone is *NOT* freed actually here because it is alloced from + * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags. + */ + __blk_put_request(clone->q, clone); + + /* + * Actual request completion is done in a softirq context which doesn't + * hold the queue lock. Otherwise, deadlock could occur because: + * - another request may be submitted by the upper level driver + * of the stacking during the completion + * - the submission which requires queue lock may be done + * against this queue + */ + dm_complete_request(clone, error); +} + static sector_t max_io_len(struct mapped_device *md, sector_t sector, struct dm_target *ti) { @@ -636,11 +942,6 @@ static void __map_bio(struct dm_target *ti, struct bio *clone, sector_t sector; struct mapped_device *md; - /* - * Sanity checks. - */ - BUG_ON(!clone->bi_size); - clone->bi_end_io = clone_endio; clone->bi_private = tio; @@ -656,8 +957,7 @@ static void __map_bio(struct dm_target *ti, struct bio *clone, /* 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, - clone->bi_sector, sector); + tio->io->bio->bi_bdev->bd_dev, sector); generic_make_request(clone); } else if (r < 0 || r == DM_MAPIO_REQUEUE) { @@ -755,6 +1055,48 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector, 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 flush_nr) +{ + struct dm_target_io *tio = alloc_tio(ci, ti); + struct bio *clone; + + tio->info.flush_request = flush_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, flush_nr; + 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); + + ci->sector_count = 0; + + return 0; +} + static int __clone_and_map(struct clone_info *ci) { struct bio *clone, *bio = ci->bio; @@ -762,6 +1104,9 @@ static int __clone_and_map(struct clone_info *ci) 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; @@ -771,10 +1116,7 @@ static int __clone_and_map(struct clone_info *ci) /* * Allocate a target io object. */ - tio = alloc_tio(ci->md); - tio->io = ci->io; - tio->ti = ti; - memset(&tio->info, 0, sizeof(tio->info)); + tio = alloc_tio(ci, ti); if (ci->sector_count <= max) { /* @@ -830,10 +1172,7 @@ static int __clone_and_map(struct clone_info *ci) max = max_io_len(ci->md, ci->sector, ti); - tio = alloc_tio(ci->md); - tio->io = ci->io; - tio->ti = ti; - memset(&tio->info, 0, sizeof(tio->info)); + tio = alloc_tio(ci, ti); } len = min(remaining, max); @@ -868,7 +1207,8 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) if (!bio_barrier(bio)) bio_io_error(bio); else - md->barrier_error = -EIO; + if (!md->barrier_error) + md->barrier_error = -EIO; return; } @@ -881,6 +1221,8 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) ci.io->md = md; 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); @@ -928,6 +1270,16 @@ static int dm_merge_bvec(struct request_queue *q, */ 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); @@ -946,7 +1298,7 @@ out: * 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) +static int _dm_request(struct request_queue *q, struct bio *bio) { int rw = bio_data_dir(bio); struct mapped_device *md = q->queuedata; @@ -983,12 +1335,274 @@ static int dm_request(struct request_queue *q, struct bio *bio) return 0; } +static int dm_make_request(struct request_queue *q, struct bio *bio) +{ + struct mapped_device *md = q->queuedata; + + if (unlikely(bio_barrier(bio))) { + bio_endio(bio, -EOPNOTSUPP); + return 0; + } + + 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); +} + +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 = 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 int dm_rq_flush_suspending(struct mapped_device *md) +{ + return !md->suspend_rq.special; +} + +/* + * Called with the queue lock held. + */ +static int dm_prep_fn(struct request_queue *q, struct request *rq) +{ + struct mapped_device *md = q->queuedata; + struct dm_rq_target_io *tio; + struct request *clone; + + if (unlikely(rq == &md->suspend_rq)) { + if (dm_rq_flush_suspending(md)) + return BLKPREP_OK; + else + /* The flush suspend was interrupted */ + return BLKPREP_KILL; + } + + if (unlikely(rq->special)) { + DMWARN("Already has something in rq->special."); + return BLKPREP_KILL; + } + + tio = alloc_rq_tio(md); /* Only one for each original request */ + if (!tio) + /* -ENOMEM */ + return BLKPREP_DEFER; + + 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 BLKPREP_DEFER; + } + + rq->special = clone; + rq->cmd_flags |= REQ_DONTPREP; + + return BLKPREP_OK; +} + +static void map_request(struct dm_target *ti, struct request *rq, + struct mapped_device *md) +{ + int r; + struct request *clone = rq->special; + 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 */ + dm_dispatch_request(clone); + break; + case DM_MAPIO_REQUEUE: + /* The target wants to requeue the I/O */ + dm_requeue_unmapped_request(clone); + 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; + } +} + +/* + * 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_table(md); + struct dm_target *ti; + struct request *rq; + + /* + * For noflush suspend, check blk_queue_stopped() to immediately + * quit I/O dispatching. + */ + while (!blk_queue_plugged(q) && !blk_queue_stopped(q)) { + rq = blk_peek_request(q); + if (!rq) + goto plug_and_out; + + if (unlikely(rq == &md->suspend_rq)) { /* Flush suspend maker */ + if (queue_in_flight(q)) + /* Not quiet yet. Wait more */ + goto plug_and_out; + + /* This device should be quiet now */ + __stop_queue(q); + blk_start_request(rq); + __blk_end_request_all(rq, 0); + wake_up(&md->wait); + 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); + spin_unlock(q->queue_lock); + map_request(ti, rq, md); + spin_lock_irq(q->queue_lock); + } + + goto out; + +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_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_table(md); if (map) { + if (dm_request_based(md)) + generic_unplug_device(q); + dm_table_unplug_all(map); dm_table_put(map); } @@ -1003,7 +1617,16 @@ static int dm_any_congested(void *congested_data, int bdi_bits) if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { map = dm_get_table(md); if (map) { - r = dm_table_any_congested(map, bdi_bits); + /* + * 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); } } @@ -1126,30 +1749,32 @@ static struct mapped_device *alloc_dev(int minor) INIT_LIST_HEAD(&md->uevent_list); spin_lock_init(&md->uevent_lock); - md->queue = blk_alloc_queue(GFP_KERNEL); + md->queue = blk_init_queue(dm_request_fn, NULL); 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_ordered(md->queue, QUEUE_ORDERED_DRAIN, NULL); 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); - - md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache); - if (!md->io_pool) - goto bad_io_pool; - - md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache); - if (!md->tio_pool) - goto bad_tio_pool; - - md->bs = bioset_create(16, 0); - if (!md->bs) - goto bad_no_bioset; + 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); md->disk = alloc_disk(1); if (!md->disk) @@ -1173,6 +1798,10 @@ static struct mapped_device *alloc_dev(int minor) 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); @@ -1182,15 +1811,11 @@ static struct mapped_device *alloc_dev(int minor) return md; +bad_bdev: + destroy_workqueue(md->wq); bad_thread: put_disk(md->disk); bad_disk: - bioset_free(md->bs); -bad_no_bioset: - mempool_destroy(md->tio_pool); -bad_tio_pool: - mempool_destroy(md->io_pool); -bad_io_pool: blk_cleanup_queue(md->queue); bad_queue: free_minor(minor); @@ -1207,14 +1832,15 @@ static void free_dev(struct mapped_device *md) { int minor = MINOR(disk_devt(md->disk)); - if (md->suspended_bdev) { - unlock_fs(md); - bdput(md->suspended_bdev); - } + unlock_fs(md); + bdput(md->bdev); destroy_workqueue(md->wq); - mempool_destroy(md->tio_pool); - mempool_destroy(md->io_pool); - bioset_free(md->bs); + 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); @@ -1229,6 +1855,29 @@ static void free_dev(struct mapped_device *md) 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. */ @@ -1252,15 +1901,17 @@ static void __set_size(struct mapped_device *md, sector_t size) { set_capacity(md->disk, size); - mutex_lock(&md->suspended_bdev->bd_inode->i_mutex); - i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT); - mutex_unlock(&md->suspended_bdev->bd_inode->i_mutex); + 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); } -static int __bind(struct mapped_device *md, struct dm_table *t) +static int __bind(struct mapped_device *md, struct dm_table *t, + struct queue_limits *limits) { struct request_queue *q = md->queue; sector_t size; + unsigned long flags; size = dm_table_get_size(t); @@ -1270,8 +1921,7 @@ static int __bind(struct mapped_device *md, struct dm_table *t) if (size != get_capacity(md->disk)) memset(&md->geometry, 0, sizeof(md->geometry)); - if (md->suspended_bdev) - __set_size(md, size); + __set_size(md, size); if (!size) { dm_table_destroy(t); @@ -1280,10 +1930,22 @@ static int __bind(struct mapped_device *md, struct dm_table *t) dm_table_event_callback(t, event_callback, md); - write_lock(&md->map_lock); + /* + * 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); md->map = t; - dm_table_set_restrictions(t, q); - write_unlock(&md->map_lock); + dm_table_set_restrictions(t, q, limits); + write_unlock_irqrestore(&md->map_lock, flags); return 0; } @@ -1291,14 +1953,15 @@ static int __bind(struct mapped_device *md, struct dm_table *t) static void __unbind(struct mapped_device *md) { struct dm_table *map = md->map; + unsigned long flags; if (!map) return; dm_table_event_callback(map, NULL, NULL); - write_lock(&md->map_lock); + write_lock_irqsave(&md->map_lock, flags); md->map = NULL; - write_unlock(&md->map_lock); + write_unlock_irqrestore(&md->map_lock, flags); dm_table_destroy(map); } @@ -1402,6 +2065,8 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible) { int r = 0; DECLARE_WAITQUEUE(wait, current); + struct request_queue *q = md->queue; + unsigned long flags; dm_unplug_all(md->queue); @@ -1411,7 +2076,14 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible) set_current_state(interruptible); smp_mb(); - if (!atomic_read(&md->pending)) + if (dm_request_based(md)) { + spin_lock_irqsave(q->queue_lock, flags); + if (!queue_in_flight(q) && blk_queue_stopped(q)) { + spin_unlock_irqrestore(q->queue_lock, flags); + break; + } + spin_unlock_irqrestore(q->queue_lock, flags); + } else if (!atomic_read(&md->pending)) break; if (interruptible == TASK_INTERRUPTIBLE && @@ -1429,34 +2101,36 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible) return r; } -static int dm_flush(struct mapped_device *md) +static void dm_flush(struct mapped_device *md) { dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE); - return 0; + + 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) { - int error = dm_flush(md); + md->barrier_error = 0; - if (unlikely(error)) { - bio_endio(bio, error); - return; - } - if (bio_empty_barrier(bio)) { - bio_endio(bio, 0); - return; - } - - __split_and_process_bio(md, bio); + dm_flush(md); - error = dm_flush(md); - - if (!error && md->barrier_error) - error = md->barrier_error; + if (!bio_empty_barrier(bio)) { + __split_and_process_bio(md, bio); + dm_flush(md); + } if (md->barrier_error != DM_ENDIO_REQUEUE) - bio_endio(bio, error); + 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); + } } /* @@ -1482,10 +2156,14 @@ static void dm_wq_work(struct work_struct *work) up_write(&md->io_lock); - if (bio_barrier(c)) - process_barrier(md, c); - else - __split_and_process_bio(md, c); + if (dm_request_based(md)) + generic_make_request(c); + else { + if (bio_barrier(c)) + process_barrier(md, c); + else + __split_and_process_bio(md, c); + } down_write(&md->io_lock); } @@ -1505,6 +2183,7 @@ static void dm_queue_flush(struct mapped_device *md) */ int dm_swap_table(struct mapped_device *md, struct dm_table *table) { + struct queue_limits limits; int r = -EINVAL; mutex_lock(&md->suspend_lock); @@ -1513,19 +2192,96 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table) if (!dm_suspended(md)) goto out; - /* without bdev, the device size cannot be changed */ - if (!md->suspended_bdev) - if (get_capacity(md->disk) != dm_table_get_size(table)) - goto out; + r = dm_calculate_queue_limits(table, &limits); + if (r) + 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; + } + + /* + * It is enought that blk_queue_ordered() is called only once when + * the first bio-based table is bound. + * + * This setting should be moved to alloc_dev() when request-based dm + * supports barrier. + */ + if (!md->map && dm_table_bio_based(table)) + blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN, NULL); __unbind(md); - r = __bind(md, table); + r = __bind(md, table, &limits); out: mutex_unlock(&md->suspend_lock); return r; } +static void dm_rq_invalidate_suspend_marker(struct mapped_device *md) +{ + md->suspend_rq.special = (void *)0x1; +} + +static void dm_rq_abort_suspend(struct mapped_device *md, int noflush) +{ + struct request_queue *q = md->queue; + unsigned long flags; + + spin_lock_irqsave(q->queue_lock, flags); + if (!noflush) + dm_rq_invalidate_suspend_marker(md); + __start_queue(q); + spin_unlock_irqrestore(q->queue_lock, flags); +} + +static void dm_rq_start_suspend(struct mapped_device *md, int noflush) +{ + struct request *rq = &md->suspend_rq; + struct request_queue *q = md->queue; + + if (noflush) + stop_queue(q); + else { + blk_rq_init(q, rq); + blk_insert_request(q, rq, 0, NULL); + } +} + +static int dm_rq_suspend_available(struct mapped_device *md, int noflush) +{ + int r = 1; + struct request *rq = &md->suspend_rq; + struct request_queue *q = md->queue; + unsigned long flags; + + if (noflush) + return r; + + /* The marker must be protected by queue lock if it is in use */ + spin_lock_irqsave(q->queue_lock, flags); + if (unlikely(rq->ref_count)) { + /* + * This can happen, when the previous flush suspend was + * interrupted, the marker is still in the queue and + * this flush suspend has been invoked, because we don't + * remove the marker at the time of suspend interruption. + * We have only one marker per mapped_device, so we can't + * start another flush suspend while it is in use. + */ + BUG_ON(!rq->special); /* The marker should be invalidated */ + DMWARN("Invalidating the previous flush suspend is still in" + " progress. Please retry later."); + r = 0; + } + spin_unlock_irqrestore(q->queue_lock, flags); + + return r; +} + /* * Functions to lock and unlock any filesystem running on the * device. @@ -1536,7 +2292,7 @@ static int lock_fs(struct mapped_device *md) WARN_ON(md->frozen_sb); - md->frozen_sb = freeze_bdev(md->suspended_bdev); + md->frozen_sb = freeze_bdev(md->bdev); if (IS_ERR(md->frozen_sb)) { r = PTR_ERR(md->frozen_sb); md->frozen_sb = NULL; @@ -1545,9 +2301,6 @@ static int lock_fs(struct mapped_device *md) set_bit(DMF_FROZEN, &md->flags); - /* don't bdput right now, we don't want the bdev - * to go away while it is locked. - */ return 0; } @@ -1556,7 +2309,7 @@ static void unlock_fs(struct mapped_device *md) if (!test_bit(DMF_FROZEN, &md->flags)) return; - thaw_bdev(md->suspended_bdev, md->frozen_sb); + thaw_bdev(md->bdev, md->frozen_sb); md->frozen_sb = NULL; clear_bit(DMF_FROZEN, &md->flags); } @@ -1568,6 +2321,53 @@ static void unlock_fs(struct mapped_device *md) * 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. + * + * After the suspend starts, further incoming requests are kept in + * the request_queue and deferred. + * Remaining requests in the request_queue at the start of suspend are flushed + * if it is flush suspend. + * The suspend completes when the following conditions have been satisfied, + * so wait for it: + * 1. q->in_flight is 0 (which means no in_flight request) + * 2. queue has been stopped (which means no request dispatching) + * + * + * Noflush suspend + * --------------- + * Noflush suspend doesn't need to dispatch remaining requests. + * So stop the queue immediately. Then, wait for all in_flight requests + * to be completed or requeued. + * + * To abort noflush suspend, start the queue. + * + * + * Flush suspend + * ------------- + * Flush suspend needs to dispatch remaining requests. So stop the queue + * after the remaining requests are completed. (Requeued request must be also + * re-dispatched and completed. Until then, we can't stop the queue.) + * + * During flushing the remaining requests, further incoming requests are also + * inserted to the same queue. To distinguish which requests are to be + * flushed, we insert a marker request to the queue at the time of starting + * flush suspend, like a barrier. + * The dispatching is blocked when the marker is found on the top of the queue. + * And the queue is stopped when all in_flight requests are completed, since + * that means the remaining requests are completely flushed. + * Then, the marker is removed from the queue. + * + * To abort flush suspend, we also need to take care of the marker, not only + * starting the queue. + * We don't remove the marker forcibly from the queue since it's against + * the block-layer manner. Instead, we put a invalidated mark on the marker. + * When the invalidated marker is found on the top of the queue, it is + * immediately removed from the queue, so it doesn't block dispatching. + * Because we have only one marker per mapped_device, we can't start another + * flush suspend until the invalidated marker is removed from the queue. + * So fail and return with -EBUSY in such a case. + */ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) { struct dm_table *map = NULL; @@ -1582,6 +2382,11 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) goto out_unlock; } + if (dm_request_based(md) && !dm_rq_suspend_available(md, noflush)) { + r = -EBUSY; + goto out_unlock; + } + map = dm_get_table(md); /* @@ -1594,24 +2399,14 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) /* This does not get reverted if there's an error later. */ dm_table_presuspend_targets(map); - /* bdget() can stall if the pending I/Os are not flushed */ - if (!noflush) { - md->suspended_bdev = bdget_disk(md->disk, 0); - if (!md->suspended_bdev) { - DMWARN("bdget failed in dm_suspend"); - r = -ENOMEM; + /* + * Flush I/O to the device. noflush supersedes do_lockfs, + * because lock_fs() needs to flush I/Os. + */ + if (!noflush && do_lockfs) { + r = lock_fs(md); + if (r) goto out; - } - - /* - * Flush I/O to the device. noflush supersedes do_lockfs, - * because lock_fs() needs to flush I/Os. - */ - if (do_lockfs) { - r = lock_fs(md); - if (r) - goto out; - } } /* @@ -1637,6 +2432,9 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) flush_workqueue(md->wq); + if (dm_request_based(md)) + dm_rq_start_suspend(md, noflush); + /* * At this point no more requests are entering target request routines. * We call dm_wait_for_completion to wait for all existing requests @@ -1653,6 +2451,9 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) if (r < 0) { dm_queue_flush(md); + if (dm_request_based(md)) + dm_rq_abort_suspend(md, noflush); + unlock_fs(md); goto out; /* pushback list is already flushed, so skip flush */ } @@ -1668,11 +2469,6 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) set_bit(DMF_SUSPENDED, &md->flags); out: - if (r && md->suspended_bdev) { - bdput(md->suspended_bdev); - md->suspended_bdev = NULL; - } - dm_table_put(map); out_unlock: @@ -1699,21 +2495,20 @@ int dm_resume(struct mapped_device *md) dm_queue_flush(md); - unlock_fs(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); - if (md->suspended_bdev) { - bdput(md->suspended_bdev); - md->suspended_bdev = NULL; - } + unlock_fs(md); clear_bit(DMF_SUSPENDED, &md->flags); dm_table_unplug_all(map); - - dm_kobject_uevent(md); - r = 0; - out: dm_table_put(map); mutex_unlock(&md->suspend_lock); @@ -1724,9 +2519,19 @@ out: /*----------------------------------------------------------------- * Event notification. *---------------------------------------------------------------*/ -void dm_kobject_uevent(struct mapped_device *md) -{ - kobject_uevent(&disk_to_dev(md->disk)->kobj, KOBJ_CHANGE); +void 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) + kobject_uevent(&disk_to_dev(md->disk)->kobj, action); + else { + snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u", + DM_COOKIE_ENV_VAR_NAME, cookie); + kobject_uevent_env(&disk_to_dev(md->disk)->kobj, action, envp); + } } uint32_t dm_next_uevent_seq(struct mapped_device *md) @@ -1780,6 +2585,10 @@ struct mapped_device *dm_get_from_kobject(struct kobject *kobj) if (&md->kobj != kobj) return NULL; + if (test_bit(DMF_FREEING, &md->flags) || + test_bit(DMF_DELETING, &md->flags)) + return NULL; + dm_get(md); return md; } @@ -1800,6 +2609,61 @@ int dm_noflush_suspending(struct dm_target *ti) } 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 struct block_device_operations dm_blk_dops = { .open = dm_blk_open, .release = dm_blk_close, |