When mdstat lists spare or failed raid members before active ones, mkinitrd won't see them.  If they're necessary to bring up the root device, you lose.  Big problem, especially when the member became failed because of bug 465539, or it became spare because something went wrong in the current udev(?)-based progressive bringing up of array members (that often causes members brought in a bit too late to come up as spares needing resync).

This patch strips the (S)s and (F)s from the list of md raid components, enabling a successful probing of all member devices.  Without it, findstoragedriver returns after failing to locate a /sys/block/$device for say sda1([SF]).  I found it odd that it would return rather than continue on to the next argument, so I fixed that too.  If there's a stronger reason to return, please drop that part of the patch.

--- /tmp/mkinitrd.orig	2008-10-03 05:56:07.000000000 -0300
+++ /tmp/mkinitrd	2008-10-03 16:40:46.000000000 -0300
@@ -384,7 +384,7 @@
                 sysfs=$(for x in /sys/block/* ; do findone -type d $x/ -name $device; done)
             fi
         fi
-        [ -z "$sysfs" ] && return
+        [ -z "$sysfs" ] && continue
         qpushd $sysfs
         findstoragedriverinsys
         qpopd
@@ -582,7 +582,7 @@
     fi
 
     levels=$(awk "/^$1[	 ]*:/ { print\$4 }" /proc/mdstat)
-    devs=$(gawk "/^$1[	 ]*:/ { print gensub(\"\\\\[[0-9]*\\\\]\",\"\",\"g\",gensub(\"^md.*raid[0-9]*\",\"\",\"1\")) }" /proc/mdstat)
+    devs=$(gawk "/^$1[	 ]*:/ { print gensub(\"\\\\[[0-9]*\\\\](\\\\([SF]\\\\))?\",\"\",\"g\",gensub(\"^md.*raid[0-9]*\",\"\",\"1\")) }" /proc/mdstat)
 
     for level in $levels ; do
         case $level in