diff options
| -rw-r--r-- | drivers/md/dm-snap.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index b5b9118c063..5e553c50c21 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -1467,7 +1467,19 @@ static int snapshot_iterate_devices(struct dm_target *ti, /*----------------------------------------------------------------- * Origin methods *---------------------------------------------------------------*/ -static int __origin_write(struct list_head *snapshots, struct bio *bio) + +/* + * If no exceptions need creating, DM_MAPIO_REMAPPED is returned and any + * supplied bio was ignored. The caller may submit it immediately. + * (No remapping actually occurs as the origin is always a direct linear + * map.) + * + * If further exceptions are required, DM_MAPIO_SUBMITTED is returned + * and any supplied bio is added to a list to be submitted once all + * the necessary exceptions exist. + */ +static int __origin_write(struct list_head *snapshots, sector_t sector, + struct bio *bio) { int r = DM_MAPIO_REMAPPED, first = 0; struct dm_snapshot *snap; @@ -1486,14 +1498,14 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio) goto next_snapshot; /* Nothing to do if writing beyond end of snapshot */ - if (bio->bi_sector >= dm_table_get_size(snap->ti->table)) + if (sector >= dm_table_get_size(snap->ti->table)) goto next_snapshot; /* * Remember, different snapshots can have * different chunk sizes. */ - chunk = sector_to_chunk(snap->store, bio->bi_sector); + chunk = sector_to_chunk(snap->store, sector); /* * Check exception table to see if block @@ -1543,7 +1555,8 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio) first = 1; } - bio_list_add(&primary_pe->origin_bios, bio); + if (bio) + bio_list_add(&primary_pe->origin_bios, bio); r = DM_MAPIO_SUBMITTED; } @@ -1599,7 +1612,7 @@ static int do_origin(struct dm_dev *origin, struct bio *bio) down_read(&_origins_lock); o = __lookup_origin(origin->bdev); if (o) - r = __origin_write(&o->snapshots, bio); + r = __origin_write(&o->snapshots, bio->bi_sector, bio); up_read(&_origins_lock); return r; |