From 87176b057ef2ab61bb5bf420b38d4e0fd2484fc5 Mon Sep 17 00:00:00 2001
From: Philipp Kern <pkern@debian.org>
Date: Sat, 19 Sep 2015 23:44:08 +0200
Subject: [PATCH] Use mapdevfs to find the device of the root filesystem.

This no longer forces the device path for the root system to be a DASD.
Instead it infers the root device like on any other platform. (The
code is mostly the one lilo-installer uses.)

This requires sysconfig-hardware (>= 0.0.10+nmu3, or feature-equivalent)
in the target system to set the relevant DASDs online by using
configuration stored in the initrd. It is copied into the final system
by s390-sysconfig-writer.
---
 debian/changelog               |  6 ++++++
 debian/zipl-installer.postinst | 22 +++++++++++++---------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/debian/changelog b/debian/changelog
index 8d5fcb9..85d6680 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+zipl-installer (0.0.28) UNRELEASED; urgency=medium
+
+  * Use mapdevfs to find the device of the root filesystem.
+
+ -- Philipp Kern <pkern@debian.org>  Sat, 19 Sep 2015 23:41:42 +0200
+
 zipl-installer (0.0.27) unstable; urgency=medium
 
   * Log the output of zipl to syslog.
diff --git a/debian/zipl-installer.postinst b/debian/zipl-installer.postinst
index 2eeb5bd..c70ab6f 100755
--- a/debian/zipl-installer.postinst
+++ b/debian/zipl-installer.postinst
@@ -2,19 +2,23 @@
 
 . /usr/share/debconf/confmodule
 
-findfs () {
+log() {
+	logger -t zipl-installer "$@"
+}
+
+info() {
+	log "info: $@"
+}
+
+findfs() {
 	mount | grep "on /target${1%/} " | tail -n1 | cut -d' ' -f1
 }
 
-ROOT_PLAIN="$(findfs /)"
-name="${ROOT_PLAIN#/dev/}"
-disk="${name%%[0-9]*}"
-part="${name#$disk}"
-devpath=/sys/block/$disk/$(readlink /sys/block/$disk/device) 
-dev=${devpath##*/}
-ROOT=/dev/disk/by-path/ccw-$dev-part$part
+rootfs_devfs="$(findfs /)"
+rootfs="$(mapdevfs $rootfs_devfs)"
+log "Root filesystem on ${rootfs} (${rootfs_devfs})"
 
-PARAMETER="root=$ROOT"
+PARAMETER="root=${rootfs}"
 
 cat > /target/etc/zipl.conf << EOF
 [defaultboot]
-- 
2.19.1