95dasd_rules: print out 'rd.dasd' commandline

When a DASD is found to be required for the rootfs we should
be printing out a 'rd.dasd' commandline parameter. This not
only enables us to correctly enable the device with cio_ignore,
we can also inspect the resulting initrd to figure out which
devices are required to mount the rootfs.

Signed-off-by: Hannes Reinecke <hare@suse.de>

modules.d/95dasd_rules/module-setup.sh

@@ -1,10 +1,39 @@
 #!/bin/bash
 
+# called by dracut
+cmdline() {
+    is_dasd() {
+        local _dev=$1
+        local _devpath=$(cd -P /sys/dev/block/$_dev ; echo $PWD)
+
+        [ "${_devpath#*/dasd}" == "$_devpath" ] && return 1
+        _ccw="${_devpath%%/block/*}"
+        echo "rd.dasd=${_ccw##*/}"
+        return 0
+    }
+    [[ $hostonly ]] || [[ $mount_needs ]] && {
+        for_each_host_dev_and_slaves is_dasd || return 255
+    }
+}
+
 # called by dracut
 check() {
     local _arch=$(uname -m)
+    local found=0
+    local bdev
     [ "$_arch" = "s390" -o "$_arch" = "s390x" ] || return 1
     require_binaries /usr/lib/udev/collect || return 1
+
+    [[ $hostonly ]] || [[ $mount_needs ]] && {
+        for bdev in /sys/block/* ; do
+            case "${bdev##*/}" in
+                dasd*)
+                    found=$(($found+1));
+                    break;
+            esac
+        done
+        [ $found -eq 0 ] && return 255
+    }
     return 0
 }
 
@@ -17,6 +46,10 @@ depends() {
 # called by dracut
 install() {
     inst_hook cmdline 30 "$moddir/parse-dasd.sh"
+    if [[ $hostonly_cmdline == "yes" ]] ; then
+        local _dasd=$(cmdline)
+        [[ $_dasd ]] && printf "%s\n" "$_dasd" >> "${initdir}/etc/cmdline.d/95dasd.conf"
+    fi
     if [[ $hostonly ]] ; then
         inst_rules_wildcard 51-dasd-*.rules
         inst_rules_wildcard 41-s390x-dasd-*.rules