#!/bin/ksh


#
# We maintain a list of usable cache devices that can be assigned
# to each pool as needed (think of it as an Object Pool of cache devices)
# This list lives in $ZPOOL_CACHE_DB
#


ZPOOL_CACHE_DB=/tmp/zpool_cache_devices.txt
ZPOOL_CACHE=$(cat $ZPOOL_CACHE_DB)



case $1 in

"create")
	set -A zpool_cache $ZPOOL_CACHE

	# the pool name is the first arg without a - :-)
	set -A args $@
	FOUND=""
	i=0
	while [ -z "$FOUND" ] && [ $i -le "$#" ]
	do
		i=$(($i + 1))
		FOUND=$(echo ${args[$i]} | /usr/bin/grep -v '^-')
	done	
	POOL=${args[$i]}
	/usr/sbin/zpool_real $@
	RET=$?

	if [ $RET -ne 0 ]
	then
		exit $RET
	fi
	# pull device from cache
	CACHE=${zpool_cache[0]}
	if [ -z "${CACHE}" ]
	then
		/usr/sbin/zpool_real add $POOL
	else	
		/usr/sbin/zpool_real add $POOL cache $CACHE
		cat $ZPOOL_CACHE_DB | grep -v $CACHE > ${ZPOOL_CACHE_DB}.$$
		mv ${ZPOOL_CACHE_DB}.$$ $ZPOOL_CACHE_DB
	fi	
	exit $RET
	;;

"destroy")
	# the pool name is the first arg without a - :-)
	set -A args $@
	FOUND=""
	i=0
	while [ -z "$FOUND" ] && [ $i -le "$#" ]
	do
		i=$(($i + 1))
		FOUND=$(echo ${args[$i]} | /usr/bin/grep -v '^-')
	done	
	POOL=${args[$i]}
	
	# check to see if this pool has a cache device
	CACHE_DEV=""
	/usr/sbin/zpool_real iostat -v $POOL 1 1 > /tmp/file.$$
 	grep "^cache " /tmp/file.$$ > /dev/null
	if [ $? -eq 0 ]
	then
		CACHE_DEV=$(tail -3 /tmp/file.$$ | head -1 | awk '{print $1}')
	fi
	rm /tmp/file.$$

	/usr/sbin/zpool_real $@
	RET=$?


	if [ $RET -ne 0 ]
	then
		return $RET
	fi
	
	# if we had a cache device, return it to the pool
	if [ ! -z "${CACHE_DEV}" ]
	then
		echo $CACHE_DEV >> $ZPOOL_CACHE_DB
	fi
	exit $RET
	;;
*)
	/usr/sbin/zpool_real $@
	exit $?
esac