[PATCH 9/6] generic/459: fix test running errors

["Darrick J. Wong" <darrick.wong@oracle.com>]

If the DISCARD of the thin device somehow fails with this message:

device-mapper: thin: Data device (dm-1) discard unsupported: Disabling discard passdown.

Then we can end up with arbitrary gunk in the thin device.  This causes
mkfs to fail because it's afraid to format the device.  Don't be afraid,
just zap it.  FWIW mkfs.xfs thinks that the thinp device has an xfs
external log because sometimes the thinp device just happen to be backed
by the log of the previous test's scratch fs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 tests/generic/459 |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/generic/459 b/tests/generic/459
index 7c10c2a..3dd3681 100755
--- a/tests/generic/459
+++ b/tests/generic/459
@@ -92,7 +92,7 @@ $LVM_PROG lvcreate  --virtualsize $virtsize \
 		    -T $vgname/$poolname \
 		    -n $lvname >>$seqres.full 2>&1
 
-_mkfs_dev /dev/mapper/$vgname-$lvname >>$seqres.full 2>&1
+_mkfs_dev -f /dev/mapper/$vgname-$lvname >>$seqres.full 2>&1
 
 
 # Running the test over the original volume doesn't reproduce the problem