Add cleanup option -c to zconfig.sh

Several folks have now remarked that when the regression tests
fail they leave a mess behind.  This was done intentionally at
the time to facilitate debugging the wreckage.

However, this also means that you may need to do some manual
cleanup such as removing the loopback devices before re-running
the tests.  To simplify this proceedure I've added the '-c'
option to zconfig.sh which will attempt to cleanup the mess
from a previous test before starting.

This is somewhat dangerous because it must guess as to which
loopback devices you were using.  But this risk is fairly minimal
because devices which are currently still is use can not be
cleaned up.  And because only devices with 'zpool' in the name
are considered for removal.  That said if your running parallel
copies of say zconfig.sh this may cause you some trouble.

scripts/common.sh.in

@@ -15,6 +15,7 @@ MODULES=(zlib_deflate spl splat zavl znvpair zunicode zcommon zfs)
 fi
 
 PROG="<define PROG>"
+CLEANUP=
 VERBOSE=
 VERBOSE_FLAG=
 FORCE=
@@ -207,6 +208,24 @@ unused_loop_device() {
 	die "Error: Unable to find unused loopback device"
 }
 
+#
+# This can be slightly dangerous because the loop devices we are
+# cleanup up may not be ours.  However, if the devices are currently
+# in use we will not be able to remove them, and we only remove
+# devices which include 'zpool' in the name.  So any damage we might
+# do should be limited to other zfs related testing.
+#
+cleanup_loop_devices() {
+	local TMP_FILE=`mktemp`
+
+	${LOSETUP} -a | tr -d '()' >${TMP_FILE}
+	${AWK} -F":" -v losetup="$LOSETUP" \
+	    '/zpool/ { system("losetup -d "$1) }' ${TMP_FILE}
+	${AWK} -F" " '/zpool/ { system("rm -f "$3) }' ${TMP_FILE}
+
+	rm -f ${TMP_FILE}
+}
+
 #
 # The following udev helper functions assume that the provided
 # udev rules file will create a /dev/disk/zpool/<CHANNEL><RANK>

scripts/zconfig.sh

@@ -16,7 +16,7 @@ PROG=zconfig.sh
 usage() {
 cat << EOF
 USAGE:
-$0 [hv]
+$0 [hvc]
 
 DESCRIPTION:
 	ZFS/ZPOOL configuration tests
@@ -24,11 +24,12 @@ DESCRIPTION:
 OPTIONS:
 	-h      Show this message
 	-v      Verbose
+	-c      Cleanup lo+file devices at start
 
 EOF
 }
 
-while getopts 'hv' OPTION; do
+while getopts 'hvc?' OPTION; do
 	case $OPTION in
 	h)
 		usage
@@ -37,6 +38,9 @@ while getopts 'hv' OPTION; do
 	v)
 		VERBOSE=1
 		;;
+	c)
+		CLEANUP=1
+		;;
 	?)
 		usage
 		exit
@@ -48,6 +52,12 @@ if [ $(id -u) != 0 ]; then
 	die "Must run as root"
 fi
 
+# Perform pre-cleanup is requested
+if [ ${CLEANUP} ]; then
+	cleanup_loop_devices
+	rm -f /tmp/zpool.cache.*
+fi
+
 zconfig_partition() {
 	local DEVICE=$1
 	local START=$2