diff options
| -rw-r--r-- | drivers/md/dm-snap.c | 33 | ||||
| -rw-r--r-- | drivers/md/dm-snap.h | 12 |
2 files changed, 45 insertions, 0 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index d92980177b5..1c6485404db 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -39,6 +39,9 @@ */ #define SNAPSHOT_PAGES 256 +struct workqueue_struct *ksnapd; +static void flush_queued_bios(void *data); + struct pending_exception { struct exception e; @@ -488,6 +491,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) s->active = 0; s->last_percent = 0; init_rwsem(&s->lock); + spin_lock_init(&s->pe_lock); s->table = ti->table; /* Allocate hash table for COW data */ @@ -523,6 +527,9 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) goto bad6; } + bio_list_init(&s->queued_bios); + INIT_WORK(&s->queued_bios_work, flush_queued_bios, s); + /* Add snapshot to the list of snapshots for this origin */ /* Exceptions aren't triggered till snapshot_resume() is called */ if (register_snapshot(s)) { @@ -561,6 +568,8 @@ static void snapshot_dtr(struct dm_target *ti) { struct dm_snapshot *s = (struct dm_snapshot *) ti->private; + flush_workqueue(ksnapd); + /* Prevent further origin writes from using this snapshot. */ /* After this returns there can be no new kcopyd jobs. */ unregister_snapshot(s); @@ -594,6 +603,19 @@ static void flush_bios(struct bio *bio) } } +static void flush_queued_bios(void *data) +{ + struct dm_snapshot *s = (struct dm_snapshot *) data; + struct bio *queued_bios; + unsigned long flags; + + spin_lock_irqsave(&s->pe_lock, flags); + queued_bios = bio_list_get(&s->queued_bios); + spin_unlock_irqrestore(&s->pe_lock, flags); + + flush_bios(queued_bios); +} + /* * Error a list of buffers. */ @@ -1240,8 +1262,17 @@ static int __init dm_snapshot_init(void) goto bad5; } + ksnapd = create_singlethread_workqueue("ksnapd"); + if (!ksnapd) { + DMERR("Failed to create ksnapd workqueue."); + r = -ENOMEM; + goto bad6; + } + return 0; + bad6: + mempool_destroy(pending_pool); bad5: kmem_cache_destroy(pending_cache); bad4: @@ -1259,6 +1290,8 @@ static void __exit dm_snapshot_exit(void) { int r; + destroy_workqueue(ksnapd); + r = dm_unregister_target(&snapshot_target); if (r) DMERR("snapshot unregister failed %d", r); diff --git a/drivers/md/dm-snap.h b/drivers/md/dm-snap.h index 221eb8880c8..15fa2ae6cdc 100644 --- a/drivers/md/dm-snap.h +++ b/drivers/md/dm-snap.h @@ -10,7 +10,9 @@ #define DM_SNAPSHOT_H #include "dm.h" +#include "dm-bio-list.h" #include <linux/blkdev.h> +#include <linux/workqueue.h> struct exception_table { uint32_t hash_mask; @@ -112,10 +114,20 @@ struct dm_snapshot { struct exception_table pending; struct exception_table complete; + /* + * pe_lock protects all pending_exception operations and access + * as well as the snapshot_bios list. + */ + spinlock_t pe_lock; + /* The on disk metadata handler */ struct exception_store store; struct kcopyd_client *kcopyd_client; + + /* Queue of snapshot writes for ksnapd to flush */ + struct bio_list queued_bios; + struct work_struct queued_bios_work; }; /* |