dracut is too "clever" at identifying modules to exclude.

[Neil Brown <neilb-IBi9RG/b67k@public.gmane.org>]

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If I have booted a kernel with md/raid built in (no modules) and
I use dracut to build the initramfs for a different kernel which
has the md code compiled as separate modules, then it does not include
the required md modules in the initramfs.

As a particular instance this happen when the root filesystem is on
RAID0.  The 'raid0.ko' module is not included and boot fails.

https://bugzilla.opensuse.org/show_bug.cgi?id=935993

This only happens when 'host-only' is selected (which is the default for
openSUSE).

the modules.d/90mdraid/module-setup.sh code calls

    instmods =drivers/md

instmods calls
   module_is_host_only "raid0"
and this incorrectly fails.

If raid0.ko didn't have any alias this would succeed, but it does.

$ modinfo -F alias raid0
md-level-0
md-raid0
md-personality-2

However these aliases don't appear in any modalias file in /sys/devices,
in /proc/crypto, or in /proc/modules.

Maybe you could parse /proc/mdstat..

if [ -f /proc/mdstat ]; then
  while read _d _c _a _m _x; do
   if [ "$_c" = ':' -a "$_a" = 'active' ]; then
      host_modalias["md-$_m"]=1
   fi
  done < /proc/mdstat
fi

but it all seems rather fragile.  There are probably other modules that
might miss out accidentally. dm?

Do we really need the host_modalias stuff?

Thanks,
NeilBrown

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