Systemd init support for loading cache volumes

README

@@ -27,5 +27,12 @@ This builds both the flashcache.ko and 3 utilities.
 flascache-sa-guide.txt has details on how to create and load
 flashcache volumes.
 
+Loading flashcache volumes on Systemd :
+-------------------------------------
+On folder "systemd" you will find the necessary components and a
+README file that describes how to set up those files to load
+flashcache volumes when using this init system.
+
 Mohan Srinivasan
 Paul Saab
+Manuel Bernal-Llinares

systemd/README

@@ -0,0 +1,21 @@
+Systemd bootup for Flashcache
+Author: Manuel Bernal Llinares
+------------------------------
+
+This folder contains three files for loading flashcache volumes when booting
+the system:
+    - flashcache.service, contains the service definition, usually placed at /etc/systemd/system/flashcache.service,
+    with permissions 664.
+    - flashcache_loader, this script is called by the service "start" action, it parses the flashcachetab file, and
+    calls flashcache_load to activate the cache volumes specified on the file.
+    - flashcachetab, this file contains a flashcache volume per line, with optional volume name, to be activated by
+    flashcache_loader script.
+    - flashcache_vol.conf, sysctl style file with configuration parameters for the cache volumes
+
+All these files should be installed at:
+/etc/systemd/system/flashcache.service
+/etc/init.d/flashcache_loader
+/etc/flashcache/flashcachetab
+/etc/flashcache/flashcache_vol.conf (optional)
+
+This files have been tested on a Debian 8.4, using flashcache compiled from its source code at github.com/facebookarchive/flashcache

systemd/flashcache.service

@@ -0,0 +1,15 @@
+[Unit]
+Description=Flashcache volumes loading service
+DefaultDependencies=no
+Requires=lvm2-monitor.service -.mount boot.mount lvm2-activation-early.service lvm2-activation.service systemd-fsck-root.service systemd-remount-fs.service
+After=lvm2-monintor.service -.mount boot.mount lvm2-activation-early.service lvm2-activation.service systemd-fsck-root.service systemd-remount-fs.service
+Wants=lvm2-monitor.service lvm2-activation-early.service lvm2-activation.service
+Before=checkfs.service mountall.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=no
+ExecStart=/etc/init.d/flashcache_loader
+
+[Install]
+WantedBy=default.target

systemd/flashcache_loader

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+# PATH
+#PATH=/sbin:/bin:/usr/bin
+EGREP=$(which egrep)
+SYSCTL=$(which sysctl)
+
+# File with cache volumes listing
+ETC_FLASHCACHE=/etc/flashcache
+FLASHCACHETAB=$ETC_FLASHCACHE/flashcachetab
+VOLUMES_SYSCTL_PARAMS=$ETC_FLASHCACHE/flashcache_vol.conf
+
+cat "$FLASHCACHETAB" | $EGREP -v "^#" | while read line ;
+    do
+        items=($line)
+        echo "Loading ${items[0]} (${items[1]})"
+        if flashcache_load ${items[0]} ${items[1]} 2> /dev/null; then
+           echo "Flashcache volume ${items[1]} loaded from ${items[0]}"
+        else
+            (>&2 echo "ERROR loading Flashcache volume ${items[1]} loaded from ${items[0]}") 
+        fi
+    done
+if [ -f "$VOLUMES_SYSCTL_PARAMS" ] ; then 
+    echo "Loading cache volumes configuration from $VOLUMES_SYSCTL_PARAMS"
+    $SYSCTL -p "$VOLUMES_SYSCTL_PARAMS"
+else
+    echo "No cache volumes configuration file has been found!"
+fi

systemd/flashcache_vol.conf

@@ -0,0 +1,6 @@
+# Configuration parameters for the flashcache cache volumes
+#
+# The easiest way to customize your cache volumes parameters is, once the volumes
+# have been created, run
+# sysctl -a | grep flashcache >> /etc/flashcache/flashcache_vol.conf
+# Then, edit the file to tweak the parameters for each volume

systemd/flashcachetab

@@ -0,0 +1,2 @@
+# This file contains a list of devices from which to load flashcache volumes
+# <cache_device>    <optional_cache_volume_name>