[PATCH] device-mapper snapshot: barriers not supported
The snapshot and origin targets are incapable of handling barriers and need to
indicate this.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index ad9b61f..f3759dd7 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -792,6 +792,9 @@
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
@@ -1058,6 +1061,9 @@
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;
}