mdadm: load md_mod first

Load md_mod first before setting module parameter legacy_async_del_gendisk
Everything works well if md_mod is built in kernel. If not, create and
assemble will fail.

Signed-off-by: Xiao Ni <xni@redhat.com>

Author: XiaoNi87

mdadm.h

@@ -860,7 +860,7 @@ extern int restore_stripes(int *dest, unsigned long long *offsets,
 			   unsigned long long start, unsigned long long length,
 			   char *src_buf);
 extern bool sysfs_is_libata_allow_tpm_enabled(const int verbose);
-extern bool init_md_mod_param(void);
+extern bool init_md_mod(void);
 
 #ifndef Sendmail
 #define Sendmail "/usr/lib/sendmail -t"

mdopen.c

@@ -38,33 +38,15 @@ int create_named_array(char *devnm)
 	};
 
 	fd = open(new_array_file, O_WRONLY);
-	if (fd < 0 && errno == ENOENT) {
-		char buf[PATH_MAX] = {0};
-		char *env_ptr;
-
-		env_ptr = getenv("PATH");
-		/*
-		 * When called by udev worker context, path of modprobe
-		 * might not be in env PATH. Set sbin paths into PATH
-		 * env to avoid potential failure when run modprobe here.
-		 */
-		if (env_ptr)
-			snprintf(buf, PATH_MAX - 1, "%s:%s", env_ptr,
-				 "/sbin:/usr/sbin:/usr/local/sbin");
-		else
-			snprintf(buf, PATH_MAX - 1, "%s",
-				 "/sbin:/usr/sbin:/usr/local/sbin");
-
-		setenv("PATH", buf, 1);
-
-		if (system("modprobe md_mod") == 0)
-			fd = open(new_array_file, O_WRONLY);
-	}
 	if (fd >= 0) {
 		n = write(fd, devnm, strlen(devnm));
 		close(fd);
+	} else {
+		pr_err("Fail to open %s\n", new_array_file);
+		return 0;
 	}
-	if (fd < 0 || n != (int)strlen(devnm)) {
+
+	if (n != (int)strlen(devnm)) {
 		pr_err("Fail to create %s when using %s, fallback to creation via node\n",
 			devnm, new_array_file);
 		return 0;
@@ -148,7 +130,7 @@ int create_mddev(char *dev, char *name, int trustworthy,
 	char devnm[32];
 	char cbuf[400];
 
-	if (!init_md_mod_param()) {
+	if (!init_md_mod()) {
 		pr_err("init md module parameters fail\n");
 		return -1;
 	}

util.c

@@ -2583,10 +2583,41 @@ bool set_md_mod_parameter(const char *name, const char *value)
 	return ret;
 }
 
-/* Init kernel md_mod parameters here if needed */
-bool init_md_mod_param(void)
+/* Init kernel md_mod and parameters here if needed */
+bool init_md_mod(void)
 {
 	bool ret = true;
+	char module_path[32];
+	FILE *fp;
+
+	snprintf(module_path, sizeof(module_path), "/sys/module/md_mod");
+	fp = fopen(module_path, "r");
+	if (fp == NULL) {
+
+		char buf[PATH_MAX] = {0};
+		char *env_ptr;
+
+		env_ptr = getenv("PATH");
+		/*
+		 * When called by udev worker context, path of modprobe
+		 * might not be in env PATH. Set sbin paths into PATH
+		 * env to avoid potential failure when run modprobe here.
+		 */
+		if (env_ptr)
+			snprintf(buf, PATH_MAX - 1, "%s:%s", env_ptr,
+				 "/sbin:/usr/sbin:/usr/local/sbin");
+		else
+			snprintf(buf, PATH_MAX - 1, "%s",
+				 "/sbin:/usr/sbin:/usr/local/sbin");
+
+		setenv("PATH", buf, 1);
+
+		if (system("modprobe md_mod") != 0) {
+			pr_err("Can't load kernel module md_mod\n");
+			return false;
+		}
+	} else
+		fclose(fp);
 
 	/*
 	 * In kernel 9e59d609763f calls del_gendisk in sync way. So device