systemd: various fixes for boot with container-arrays.

1/ Add systemd shutdown script to ensure DDF and IMSM are
   clean before we actually shutdown

2/ Get udev to tell systemd to run the [email protected]
   units when a member array appears.

   If we boot off a member array (with dracut at least),
   the mdmon started in the initramfs will lose track of
   /sys etc, so we need to restart it.
   systemd will try to forget about it too (but not actually
   kill it because we said not to do this).
   Having udev tell it to start it will allow a new mdmon to
   run which can see /sys, and systemd will know about it.

3/ Always use --offroot and --takeover when starting mdmon with
   systemd
   --offroot is needed else shutdown will hang.
   --takeover is needed incase an mdmon was started earlier
   (e.g. in initramfs).
   Neither hurt if they aren't actually needed.

Signed-off-by: NeilBrown <[email protected]>

Author: neilbrown

Makefile

@@ -288,6 +288,7 @@ install-systemd: systemd/[email protected]
 	$(INSTALL) -D -m 644 systemd/mdmonitor.service $(DESTDIR)$(SYSTEMD_DIR)/mdmonitor.service
 	$(INSTALL) -D -m 644 systemd/[email protected] $(DESTDIR)$(SYSTEMD_DIR)/[email protected]
 	$(INSTALL) -D -m 644 systemd/[email protected] $(DESTDIR)$(SYSTEMD_DIR)/[email protected]
+	$(INSTALL) -D -m 755 systemd/mdadm.shutdown $(DESTDIR)$(SYSTEMD_DIR)-shutdown/mdadm.shutdown
 	if [ -f /etc/SuSE-release -o -n "$(SUSE)" ] ;then $(INSTALL) -D -m 755 systemd/SUSE-mdadm_env.sh $(DESTDIR)$(SYSTEMD_DIR)/../scripts/mdadm_env.sh ;fi
 
 uninstall:

systemd/mdadm.shutdown

@@ -0,0 +1,4 @@
+#!/bin/sh
+# We need to ensure all md arrays with external metadata
+# (e.g. IMSM, DDF) are clean before completing the shutdown.
+/sbin/mdadm --wait-clean --scan

systemd/[email protected]

@@ -14,7 +14,15 @@ Before=initrd-switch-root.target
 # mdmon should never complain due to lack of a platform,
 # that is mdadm's job if at all.
 Environment=IMSM_NO_PLATFORM=1
-ExecStart=/sbin/mdmon %I
+# The mdmon starting in the initramfs (with dracut at least)
+# cannot see sysfs after root is mounted, so we will have to
+# 'takeover'.  As the '--offroot --takeover' don't hurt when
+# not necessary, are are useful with root-on-md in dracut,
+# have them always present.
+ExecStart=/sbin/mdmon --offroot --takeover %I
 Type=forking
-PIDFile=/run/mdadm/%I.pid
+# Don't set the PIDFile.  It isn't necessary (systemd can work
+# it out) and systemd will remove it when transitioning from
+# initramfs to rootfs.
+#PIDFile=/run/mdadm/%I.pid
 KillMode=none

udev-md-raid-arrays.rules

@@ -34,4 +34,8 @@ ENV{ID_FS_USAGE}=="filesystem|other", ENV{ID_FS_LABEL_ENC}=="?*", SYMLINK+="disk
 
 ENV{MD_LEVEL}=="raid[1-9]*", ENV{SYSTEMD_WANTS}+="mdmonitor.service"
 
+# Tell systemd to run mdmon for our container, if we need it.
+ENV{MD_LEVEL}=="raid[1-9]*", ENV{MD_CONTAINER}=="?*", PROGRAM="/usr/bin/readlink $env{MD_CONTAINER}", ENV{MD_MON_THIS}="%c"
+ENV{MD_MON_THIS}=="?*", PROGRAM="/usr/bin/basename $env{MD_MON_THIS}", ENV{SYSTEMD_WANTS}+="mdmon@%c.service"
+
 LABEL="md_end"