diff --git a/udev/zvol_id.c b/udev/zvol_id.c
index 5960b97878..6093495947 100644
--- a/udev/zvol_id.c
+++ b/udev/zvol_id.c
@@ -51,7 +51,7 @@ const char *__asan_default_options(void) {
 int
 main(int argc, const char *const *argv)
 {
-	if (argc != 2) {
+	if (argc != 2 || strncmp(argv[1], "/dev/zd", 7) != 0) {
 		fprintf(stderr, "usage: %s /dev/zdX\n", argv[0]);
 		return (1);
 	}
@@ -72,9 +72,10 @@ main(int argc, const char *const *argv)
 		return (1);
 	}
 
-	unsigned int dev_part = minor(sb.st_rdev) % ZVOL_MINORS;
-	if (dev_part != 0)
-		sprintf(zvol_name + strlen(zvol_name), "-part%u", dev_part);
+	const char *dev_part = strrchr(dev_name, 'p');
+	if (dev_part != NULL) {
+		sprintf(zvol_name + strlen(zvol_name), "-part%s", dev_part + 1);
+	}
 
 	for (size_t i = 0; i < strlen(zvol_name); ++i)
 		if (isblank(zvol_name[i]))