klibc - May 2006 - [patch] skip existing md devices

The following patch will ignore already configured md devices in
kinit.  The rationale is that, if an md device already exists, it was
previously assembled by some other tool (e.g. mdadm) and should remain
there.  Currently, kinit removes it and attempts to recreate it, which
can cause all sorts of issues, especially in the situation that, the
md device is further encrypted and/or is an lvm volume.

Signed-off-by: Aaron Griffin <aaron@archlinux.org>

--- a/usr/kinit/do_mounts_md.c	2006-05-08 12:59:42.000000000 -0500
+++ b/usr/kinit/do_mounts_md.c	2006-05-10 11:07:08.000000000 -0500
@@ -222,6 +222,7 @@
 		char *devname;
 		mdu_disk_info_t dinfo;
 		char name[16];
+		struct stat st;

 		dev_minor = md_setup_args[ent].minor;
 		partitioned = md_setup_args[ent].partitioned;
@@ -230,6 +231,9 @@
 		snprintf(name, sizeof name,
 			 "/dev/md%s%d", partitioned?"_d":"",
dev_minor);

+		if (stat(name,&st) == 0)
+			continue;
+
 		if (partitioned)
 			dev = makedev(mdp_major(), dev_minor << MdpMinorShift);
 		else

Aaron Griffin wrote:
> The following patch will ignore already configured md devices in
> kinit.  The rationale is that, if an md device already exists, it was
> previously assembled by some other tool (e.g. mdadm) and should remain
> there.  Currently, kinit removes it and attempts to recreate it, which
> can cause all sorts of issues, especially in the situation that, the
> md device is further encrypted and/or is an lvm volume.
I'm not sure if the existence of a device node in /dev should be sufficient
to suppress
operation on that md device.  It would probably be better off querying the md
device for
its state (via the GET_ARRAY_INFO) ioctl and skip it if it is running (or even
just
assembled?)

[Neil: do you have any opinion on this?]

	-hpa