diff --git a/src/zfs-auto-snapshot.sh b/src/zfs-auto-snapshot.sh
index 0c2c03c..3a3a717 100755
--- a/src/zfs-auto-snapshot.sh
+++ b/src/zfs-auto-snapshot.sh
@@ -27,6 +27,10 @@ while [ "$#" -gt 0 ]; do
 			shift 2
 			;;
 		--label)
+			if [ "$#" -lt 2 ] || [ -z "$2" ]; then
+				echo "Error: --label requires a non-empty argument" >&2
+				exit 1
+			fi
 			opt_label="$2"
 			shift 2
 			;;
@@ -42,6 +46,10 @@ while [ "$#" -gt 0 ]; do
 			shift 2
 			;;
 		--prefix)
+			if [ "$#" -lt 2 ] || [ -z "$2" ]; then
+				echo "Error: --prefix requires a non-empty argument" >&2
+				exit 1
+			fi
 			opt_prefix="$2"
 			shift 2
 			;;
@@ -60,11 +68,11 @@ done
 ZPOOL_STATUS=$(env LC_ALL=C zpool status 2>&1)
 
 # Identify pools that should NOT receive snapshots:
-# - Pools currently running a scrub (to avoid additional I/O load).
+# - Pools currently running a scrub or resilver (to avoid additional I/O load).
 # - Pools in unhealthy states (anything other than ONLINE or DEGRADED).
 ZPOOLS_EXCLUDED=$(echo "$ZPOOL_STATUS" | awk -F ': ' '
 	$1 ~ /^ *pool$/ { pool = $2 }
-	$1 ~ /^ *scan$/ && $2 ~ /scrub in progress/ { print pool }
+	$1 ~ /^ *scan$/ && $2 ~ /(scrub|resilver) in progress/ { print pool }
 	$1 ~ /^ *state$/ && $2 !~ /ONLINE|DEGRADED/ { print pool }
 ' | sort -u)