mdadm/Build:check the level parameter when build new array

check if user forgets to specify the --level
when build a new array. such as:
./mdadm -B /dev/md0 -n2 /dev/loop[0-1]

Signed-off-by: Zhilong Liu <zlliu@suse.com>
Signed-off-by: Jes Sorensen <Jes.Sorensen@gmail.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/Build.c b/Build.c
index 74a440e7..a5fcc06b 100644
--- a/Build.c
+++ b/Build.c
@@ -56,6 +56,10 @@ int Build(char *mddev, struct mddev_dev *devlist,
 	int uuid[4] = {0,0,0,0};
 	struct map_ent *map = NULL;
 
+	if (s->level == UnSet) {
+		pr_err("a RAID level is needed to Build an array.\n");
+		return 1;
+	}
 	/* scan all devices, make sure they really are block devices */
 	for (dv = devlist; dv; dv=dv->next) {
 		subdevs++;