tests: always zero disk header

It appear that older wipefs doesn't wipe partition table.
So ensure there is no partition on LVM_TEST_BACKING_DEVICE.

diff --git a/test/lib/aux.sh b/test/lib/aux.sh
index 1af43d03e43de2b3e3f8b889703068b5da512f05..0e59d6e2cda70bf189b21a9bcc9745af91f77111 100644 (file)
--- a/test/lib/aux.sh
+++ b/test/lib/aux.sh
@@ -497,6 +497,8 @@ prepare_devs() {
        # non-ephemeral devices need to be cleared between tests
        test -f LOOP || for d in ${DEVICES[@]}; do
                blkdiscard "$d" 2>/dev/null || true
+               # ensure disk header is always zeroed
+               dd if=/dev/zero of="$d" bs=4096 count=1
                wipefs -a "$d" 2>/dev/null || dd if=/dev/zero of="$d" bs=64K count=1
        done