diff options
| -rw-r--r-- | drivers/md/dm-bio-list.h | 14 | ||||
| -rw-r--r-- | drivers/md/dm.c | 105 | ||||
| -rw-r--r-- | drivers/md/dm.h | 2 | ||||
| -rw-r--r-- | include/linux/device-mapper.h | 3 |
4 files changed, 114 insertions, 10 deletions
diff --git a/drivers/md/dm-bio-list.h b/drivers/md/dm-bio-list.h index bbf4615f0e30..da4349649f7f 100644 --- a/drivers/md/dm-bio-list.h +++ b/drivers/md/dm-bio-list.h @@ -44,6 +44,20 @@ static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2) bl->tail = bl2->tail; } +static inline void bio_list_merge_head(struct bio_list *bl, + struct bio_list *bl2) +{ + if (!bl2->head) + return; + + if (bl->head) + bl2->tail->bi_next = bl->head; + else + bl->tail = bl2->tail; + + bl->head = bl2->head; +} + static inline struct bio *bio_list_pop(struct bio_list *bl) { struct bio *bio = bl->head; diff --git a/drivers/md/dm.c b/drivers/md/dm.c index d8544e1a4c1f..fe7c56e10435 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -68,10 +68,12 @@ union map_info *dm_get_mapinfo(struct bio *bio) #define DMF_FROZEN 2 #define DMF_FREEING 3 #define DMF_DELETING 4 +#define DMF_NOFLUSH_SUSPENDING 5 struct mapped_device { struct rw_semaphore io_lock; struct semaphore suspend_lock; + spinlock_t pushback_lock; rwlock_t map_lock; atomic_t holders; atomic_t open_count; @@ -90,6 +92,7 @@ struct mapped_device { atomic_t pending; wait_queue_head_t wait; struct bio_list deferred; + struct bio_list pushback; /* * The current mapping. @@ -444,23 +447,50 @@ int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo) * 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) { - if (error) + unsigned long flags; + + /* Push-back supersedes any I/O errors */ + if (error && !(io->error > 0 && __noflush_suspending(io->md))) io->error = error; if (atomic_dec_and_test(&io->io_count)) { + if (io->error == DM_ENDIO_REQUEUE) { + /* + * Target requested pushing back the I/O. + * This must be handled before the sleeper on + * suspend queue merges the pushback list. + */ + spin_lock_irqsave(&io->md->pushback_lock, flags); + if (__noflush_suspending(io->md)) + bio_list_add(&io->md->pushback, io->bio); + else + /* noflush suspend was interrupted. */ + io->error = -EIO; + spin_unlock_irqrestore(&io->md->pushback_lock, flags); + } + if (end_io_acct(io)) /* nudge anyone waiting on suspend queue */ wake_up(&io->md->wait); - blk_add_trace_bio(io->md->queue, io->bio, BLK_TA_COMPLETE); + if (io->error != DM_ENDIO_REQUEUE) { + blk_add_trace_bio(io->md->queue, io->bio, + BLK_TA_COMPLETE); + + bio_endio(io->bio, io->bio->bi_size, io->error); + } - bio_endio(io->bio, io->bio->bi_size, io->error); free_io(io->md, io); } } @@ -480,7 +510,11 @@ static int clone_endio(struct bio *bio, unsigned int done, int error) if (endio) { r = endio(tio->ti, bio, error, &tio->info); - if (r < 0) + 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 */ @@ -554,8 +588,8 @@ static void __map_bio(struct dm_target *ti, struct bio *clone, clone->bi_sector); generic_make_request(clone); - } else if (r < 0) { - /* error the io and bail out */ + } 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); /* @@ -952,6 +986,7 @@ static struct mapped_device *alloc_dev(int minor) memset(md, 0, sizeof(*md)); init_rwsem(&md->io_lock); init_MUTEX(&md->suspend_lock); + spin_lock_init(&md->pushback_lock); rwlock_init(&md->map_lock); atomic_set(&md->holders, 1); atomic_set(&md->open_count, 0); @@ -1282,10 +1317,12 @@ static void unlock_fs(struct mapped_device *md) int dm_suspend(struct mapped_device *md, unsigned suspend_flags) { struct dm_table *map = NULL; + unsigned long flags; DECLARE_WAITQUEUE(wait, current); struct bio *def; int r = -EINVAL; int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0; + int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0; down(&md->suspend_lock); @@ -1294,6 +1331,13 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) map = dm_get_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); @@ -1301,11 +1345,14 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) if (!md->suspended_bdev) { DMWARN("bdget failed in dm_suspend"); r = -ENOMEM; - goto out; + goto flush_and_out; } - /* Flush I/O to the device. */ - if (do_lockfs) { + /* + * Flush I/O to the device. + * noflush supersedes do_lockfs, because lock_fs() needs to flush I/Os. + */ + if (do_lockfs && !noflush) { r = lock_fs(md); if (r) goto out; @@ -1341,6 +1388,14 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) down_write(&md->io_lock); remove_wait_queue(&md->wait, &wait); + if (noflush) { + spin_lock_irqsave(&md->pushback_lock, flags); + clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); + bio_list_merge_head(&md->deferred, &md->pushback); + bio_list_init(&md->pushback); + spin_unlock_irqrestore(&md->pushback_lock, flags); + } + /* were we interrupted ? */ r = -EINTR; if (atomic_read(&md->pending)) { @@ -1349,7 +1404,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) __flush_deferred_io(md, def); up_write(&md->io_lock); unlock_fs(md); - goto out; + goto out; /* pushback list is already flushed, so skip flush */ } up_write(&md->io_lock); @@ -1359,6 +1414,25 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) r = 0; +flush_and_out: + if (r && noflush) { + /* + * Because there may be already I/Os in the pushback list, + * flush them before return. + */ + down_write(&md->io_lock); + + spin_lock_irqsave(&md->pushback_lock, flags); + clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); + bio_list_merge_head(&md->deferred, &md->pushback); + bio_list_init(&md->pushback); + spin_unlock_irqrestore(&md->pushback_lock, flags); + + def = bio_list_get(&md->deferred); + __flush_deferred_io(md, def); + up_write(&md->io_lock); + } + out: if (r && md->suspended_bdev) { bdput(md->suspended_bdev); @@ -1445,6 +1519,17 @@ int dm_suspended(struct mapped_device *md) return test_bit(DMF_SUSPENDED, &md->flags); } +int dm_noflush_suspending(struct dm_target *ti) +{ + struct mapped_device *md = dm_table_get_md(ti->table); + int r = __noflush_suspending(md); + + dm_put(md); + + return r; +} +EXPORT_SYMBOL_GPL(dm_noflush_suspending); + static struct block_device_operations dm_blk_dops = { .open = dm_blk_open, .release = dm_blk_close, diff --git a/drivers/md/dm.h b/drivers/md/dm.h index c307ca9a4c33..2f796b1436b2 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -36,12 +36,14 @@ * Definitions of return values from target end_io function. */ #define DM_ENDIO_INCOMPLETE 1 +#define DM_ENDIO_REQUEUE 2 /* * Definitions of return values from target map function. */ #define DM_MAPIO_SUBMITTED 0 #define DM_MAPIO_REMAPPED 1 +#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE /* * Suspend feature flags diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 2e5c42346c38..499f5373e213 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -40,6 +40,7 @@ typedef void (*dm_dtr_fn) (struct dm_target *ti); * < 0: error * = 0: The target will handle the io by resubmitting it later * = 1: simple remap complete + * = 2: The target wants to push back the io */ typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, union map_info *map_context); @@ -50,6 +51,7 @@ typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, * 0 : ended successfully * 1 : for some reason the io has still not completed (eg, * multipath target might want to requeue a failed io). + * 2 : The target wants to push back the io */ typedef int (*dm_endio_fn) (struct dm_target *ti, struct bio *bio, int error, @@ -188,6 +190,7 @@ int dm_wait_event(struct mapped_device *md, int event_nr); const char *dm_device_name(struct mapped_device *md); struct gendisk *dm_disk(struct mapped_device *md); int dm_suspended(struct mapped_device *md); +int dm_noflush_suspending(struct dm_target *ti); /* * Geometry functions. |
