The snapshot and origin targets are incapable of handling barriers and need to indicate this. http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/dm-snapshot-barriers-not-supported.patch Index: linux-2.6.14-rc2/drivers/md/dm-snap.c =================================================================== --- linux-2.6.14-rc2.orig/drivers/md/dm-snap.c 2006-01-06 14:27:50.000000000 +0000 +++ linux-2.6.14-rc2/drivers/md/dm-snap.c 2006-01-06 14:36:26.000000000 +0000 @@ -799,6 +799,9 @@ static int snapshot_map(struct dm_target if (!s->valid) return -EIO; + if (unlikely(bio_barrier(bio))) + return -EOPNOTSUPP; + /* * Write to snapshot - higher level takes care of RW/RO * flags so we should only get this if we are @@ -1065,6 +1068,9 @@ static int origin_map(struct dm_target * struct dm_dev *dev = (struct dm_dev *) ti->private; bio->bi_bdev = dev->bdev; + if (unlikely(bio_barrier(bio))) + return -EOPNOTSUPP; + /* Only tell snapshots if this is a write */ return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : 1; } -- dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
