debvm-create: fix --skip ext4

We were truncating the output file after generating it. Instead, split
the logic and create the file prior to running mmdebstrap to make
permission failures fail early.

1 files changed, 14 insertions, 14 deletions

diff --git a/bin/debvm-create b/bin/debvm-create
index a8d5727..0e1a969 100755
--- a/bin/debvm-create
+++ b/bin/debvm-create
@@ -409,6 +409,12 @@ else
 	}
 fi
 
+if check_skip ext4; then
+	set -- "$SUITE" "$IMAGE" "$@"
+	set -x
+	exec mmdebstrap "$@"
+fi
+
 TEMPROOT=
 cleanup() {
 	if test -n "$TEMPROOT"; then
@@ -416,23 +422,17 @@ cleanup() {
 	fi
 }
 
-if check_skip ext4; then
-	set -- "$IMAGE" "$@"
-else
-	trap cleanup EXIT
-	trap 'exit 1' HUP INT QUIT TERM
-	TEMPROOT="$(mktemp -d)"
-
-	set -- "$TEMPROOT" "$@"
-fi
+trap cleanup EXIT
+trap 'exit 1' HUP INT QUIT TERM
+TEMPROOT="$(mktemp -d)"
 
-set -- "$SUITE" "$@"
+set -- "$SUITE" "$TEMPROOT" "$@"
 
 set -ex
 
-mmdebstrap "$@"
-
 # Create and truncate the file with "normal" permission.
 : >"$IMAGE"
-check_skip ext4 ||
-	run_inside_userns /sbin/mkfs.ext4 -L debvm -d "$TEMPROOT" "$IMAGE" "$SIZE"
+
+mmdebstrap "$@"
+
+run_inside_userns /sbin/mkfs.ext4 -L debvm -d "$TEMPROOT" "$IMAGE" "$SIZE"