File 1115-mdopen-modprobe-md_mod-if-it-might-be-needed.patch of Package mdadm.8578

From: NeilBrown <neilb@suse.com>
Date: Mon, 25 Sep 2017 12:15:45 +1000
Subject: [PATCH] mdopen: call "modprobe md_mod" if it might be needed.

Creating an array by opening a block-device with major number of 9
will transparently load the md module if needed.
Creating an array by opening
   /sys/module/md_mod/parameters/new_array
and writing to it won't, it will just fail if md_mod isn't loaded.

So when opening that file fails with ENOENT, run "modprobe md_mod" and
try again.

This fixes a bug whereby if you have "CREATE names=yes" in mdadm.conf,
and the md modules isn't loaded, then creating or assembling an
array will not honor the "names=yes" configuration.

Signed-off-by: NeilBrown <neilb@suse.com>
---
 mdopen.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/mdopen.c
+++ b/mdopen.c
@@ -306,6 +306,10 @@ int create_mddev(char *dev, char *name,
 		int n = -1;
 		sprintf(devnm, "md_%s", cname);
 		fd = open("/sys/module/md_mod/parameters/new_array", O_WRONLY);
+		if (fd < 0 && errno == ENOENT) {
+			system("modprobe md_mod");
+			fd = open("/sys/module/md_mod/parameters/new_array", O_WRONLY);
+		}
 		if (fd >= 0) {
 			n = write(fd, devnm, strlen(devnm));
 			close(fd);