[xfstests PATCH v3 5/5] btrfs: allow it to use $SCRATCH_LOGDEV

[Jeff Layton <jlayton@redhat.com>]

With btrfs, we can't really put the log on a separate device. What we
can do however is mirror the metadata across two devices and make the
data striped across all devices. When we turn on dmerror then the
metadata can fall back to using the other mirror while the data errors
out.

Note that the current incarnation of btrfs has a fixed 64k stripe
width. If that ever changes or becomes settable, we may need to adjust
the amount of data that the test program writes.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
 common/rc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/common/rc b/common/rc
index 83765aacfb06..078270451b53 100644
--- a/common/rc
+++ b/common/rc
@@ -830,6 +830,8 @@ _scratch_mkfs()
 		;;
 	btrfs)
 		mkfs_cmd="$MKFS_BTRFS_PROG"
+		[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
+			mkfs_cmd="$mkfs_cmd -d raid0 -m raid1 $SCRATCH_LOGDEV"
 		mkfs_filter="cat"
 		;;
 	ext3)
-- 
2.9.4