#!/bin/sh
#
# License:      GNU General Public License (GPL)
# Support:      zfs@lists.illumos.org
# Written by:   Saso Kiselkov
#
#	This script manages ZFS pools
#	It can import a ZFS pool or export it
#
#	usage: $0 {start|stop|status|monitor|validate-all|meta-data}
#
#	The "start" arg imports a ZFS pool.
#	The "stop" arg exports it.
#
#       OCF parameters are as follows
#       OCF_RESKEY_pool - the pool to import/export
#
#######################################################################
# Initialization:

: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/lib/heartbeat}
. ${OCF_FUNCTIONS_DIR}/ocf-shellfuncs

# Defaults
OCF_RESKEY_pool_default=""
OCF_RESKEY_importargs_default=""
OCF_RESKEY_importforce_default=true

: ${OCF_RESKEY_pool=${OCF_RESKEY_pool_default}}
: ${OCF_RESKEY_importargs=${OCF_RESKEY_importargs_default}}
: ${OCF_RESKEY_importforce=${OCF_RESKEY_importforce_default}}

USAGE="usage: $0 {start|stop|status|monitor|validate-all|meta-data}";

#######################################################################

meta_data() {
	cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="ZFS" version="1.0">
<version>1.0</version>
<longdesc lang="en">
This script manages ZFS pools
It can import a ZFS pool or export it
</longdesc>
<shortdesc lang="en">Manages ZFS pools</shortdesc>

<parameters>
<parameter name="pool" unique="1" required="1">
<longdesc lang="en">
The name of the ZFS pool to manage, e.g. "tank".
</longdesc>
<shortdesc lang="en">ZFS pool name</shortdesc>
<content type="string" default="${OCF_RESKEY_pool_default}" />
</parameter>
<parameter name="importargs" unique="0" required="0">
<longdesc lang="en">
Arguments to zpool import, e.g. "-d /dev/disk/by-id".
</longdesc>
<shortdesc lang="en">Import arguments</shortdesc>
<content type="string" default="${OCF_RESKEY_importargs_default}" />
</parameter>
<parameter name="importforce" unique="0" required="0">
<longdesc lang="en">
zpool import is given the -f option.
</longdesc>
<shortdesc lang="en">Import is forced</shortdesc>
<content type="boolean" default="${OCF_RESKEY_importforce_default}" />
</parameter>
</parameters>

<actions>
<action name="start"   timeout="60s" />
<action name="stop"    timeout="60s" />
<action name="monitor" depth="0"  timeout="30s" interval="5s" />
<action name="validate-all"  timeout="30s" />
<action name="meta-data"  timeout="5s" />
</actions>
</resource-agent>
END
	exit $OCF_SUCCESS
}

zpool_is_imported () {
	# Check if ZFS kstats exists
	if [ -d  /proc/spl/kstat/zfs/ ] ; then
		# Check the existence of kstats for the pool. If the stats exists, the pool was imported.
		[ -d  /proc/spl/kstat/zfs/"${OCF_RESKEY_pool}" ]
		rc=$? 
	else
		# If ZFS kstats do not exists, fallback to the standard check
		rc=$(zpool list -H "$OCF_RESKEY_pool" > /dev/null)
	fi
	return $rc
}

# Forcibly imports a ZFS pool, mounting all of its auto-mounted filesystems
# (as configured in the 'mountpoint' and 'canmount' properties)
# If the pool is already imported, no operation is taken.
zpool_import () {
	if ! zpool_is_imported; then
		ocf_log debug "${OCF_RESKEY_pool}:starting import"

		# The meanings of the options to import are as follows:
		#   -f : import even if the pool is marked as imported to another
		#        system - the system may have failed and not exported it
		#        cleanly.
		#   -o cachefile=none : the import should be temporary, so do not
		#        cache it persistently (across machine reboots). We want
		#        the CRM to explicitly control imports of this pool.
	if ocf_is_true "${OCF_RESKEY_importforce}"; then
		FORCE=-f
	else
		FORCE=""
	fi
		if zpool import $FORCE $OCF_RESKEY_importargs -o cachefile=none "$OCF_RESKEY_pool" ; then
			ocf_log debug "${OCF_RESKEY_pool}:import successful"
			return $OCF_SUCCESS
		else
			ocf_log debug "${OCF_RESKEY_pool}:import failed"
			return $OCF_ERR_GENERIC
		fi
	fi
}

# Forcibly exports a ZFS pool, unmounting all of its filesystems in the process
# If the pool is not imported, no operation is taken.
zpool_export () {
	if zpool_is_imported; then
		ocf_log debug "${OCF_RESKEY_pool}:starting export"

		# -f : force the export, even if we have mounted filesystems
		# Please note that this may fail with a "busy" error if there are
		# other kernel subsystems accessing the pool (e.g. SCSI targets).
		# Always make sure the pool export is last in your failover logic.
		if zpool export -f "$OCF_RESKEY_pool" ; then
			ocf_log debug "${OCF_RESKEY_pool}:export successful"
			return $OCF_SUCCESS
        else
			ocf_log debug "${OCF_RESKEY_pool}:export failed"
			return $OCF_ERR_GENERIC
        fi
	fi
}

# Monitors the health of a ZFS pool resource. Please note that this only
# checks whether the pool is imported and functional, not whether it has
# any degraded devices (use monitoring systems such as Zabbix for that).
zpool_monitor () {
	# If the pool is not imported, then we can't monitor its health
	if ! zpool_is_imported; then
		return $OCF_NOT_RUNNING
	fi

	# Check the pool status
	# Since version 0.7.10 status can be obtained without locks
	# https://github.com/zfsonlinux/zfs/pull/7563
	if [ -f /proc/spl/kstat/zfs/$OCF_RESKEY_pool/state ] ; then
		HEALTH=$(cat /proc/spl/kstat/zfs/$OCF_RESKEY_pool/state)
	else
		HEALTH=$(zpool list -H -o health "$OCF_RESKEY_pool")
	fi

	case "$HEALTH" in
		ONLINE|DEGRADED) return $OCF_SUCCESS;;
		FAULTED)         return $OCF_NOT_RUNNING;;
		*)               return $OCF_ERR_GENERIC;;
	esac
}

# Validates whether we can import a given ZFS pool
zpool_validate () {
	# Check that the 'zpool' command is known
	if ! which zpool > /dev/null; then
		return $OCF_ERR_INSTALLED
	fi

	# If the pool is imported, then it is obviously valid
	if zpool_is_imported; then
		return $OCF_SUCCESS
	fi

	# Check that the pool can be imported
	if zpool import $OCF_RESKEY_importargs | grep 'pool:' | grep "\\<$OCF_RESKEY_pool\\>" > /dev/null;
	then
		return $OCF_SUCCESS
	else
		return $OCF_ERR_CONFIGURED
	fi
}

usage () {
	echo "$USAGE" >&2
	return $1
}

if [ $# -ne 1 ]; then
	usage $OCF_ERR_ARGS
fi

case $1 in
	meta-data)      meta_data;;
	start)          zpool_import;;
	stop)           zpool_export;;
	status|monitor) zpool_monitor;;
	validate-all)   zpool_validate;;
	usage)          usage $OCF_SUCCESS;;
	*)              usage $OCF_ERR_UNIMPLEMENTED;;
esac

exit $?