+# Destroy the passed loopback devices, this is used when you know
+# the names of the loopback devices.
+#
+destroy_loop_devices() {
+ local LODEVICES="$1"
+
+ msg "Destroying ${LODEVICES}"
+ ${LOSETUP} -d ${LODEVICES} || \
+ die "Error $? destroying ${FILE} -> ${DEVICE} loopback"
+
+ rm -f ${FILES}
+ return 0
+}
+
+#
+# Check that the mdadm utilities are installed.
+#
+check_md_utils() {
+ test -f ${MDADM} || die "${MDADM} utility must be installed"
+ test -f ${PARTED} || die "${PARTED} utility must be installed"
+}
+
+check_md_partitionable() {
+ local LOFILE=`mktemp -p /tmp zpool-lo.XXXXXXXX`
+ local LODEVICE=`unused_loop_device`
+ local MDDEVICE=`unused_md_device`
+ local RESULT=1
+
+ check_md_utils
+
+ rm -f ${LOFILE}
+ dd if=/dev/zero of=${LOFILE} bs=1M count=0 seek=16 \
+ &>/dev/null || return ${RESULT}
+
+ msg "Creating ${LODEVICE} using ${LOFILE}"
+ ${LOSETUP} ${LODEVICE} ${LOFILE}
+ if [ $? -ne 0 ]; then
+ rm -f ${LOFILE}
+ return ${RESULT}
+ fi
+
+ msg "Creating ${MDDEVICE} using ${LODEVICE}"
+ ${MDADM} --build ${MDDEVICE} --level=faulty \
+ --raid-devices=1 ${LODEVICE} &>/dev/null
+ if [ $? -ne 0 ]; then
+ destroy_loop_devices ${LODEVICE}
+ rm -f ${LOFILE}
+ return ${RESULT}
+ fi
+ wait_udev ${MDDEVICE} 30
+
+ ${BLOCKDEV} --rereadpt ${MDDEVICE} 2>/dev/null
+ RESULT=$?
+
+ destroy_md_devices ${MDDEVICE}
+ destroy_loop_devices ${LODEVICE}
+ rm -f ${LOFILE}
+
+ return ${RESULT}
+}
+
+#
+# Find and return an unused md device.
+#
+unused_md_device() {
+ for (( i=0; i<32; i++ )); do
+ MDDEVICE=md${i}
+
+ # Skip active devicesudo in /proc/mdstat.
+ grep -q "${MDDEVICE} " /proc/mdstat && continue
+
+ # Device doesn't exist, use it.
+ if [ ! -e $/dev/{MDDEVICE} ]; then
+ echo /dev/${MDDEVICE}
+ return
+ fi
+
+ # Device exists but may not be in use.
+ if [ -b /dev/${MDDEVICE} ]; then
+ ${MDADM} --detail /dev/${MDDEVICE} &>/dev/null
+ if [ $? -eq 1 ]; then
+ echo /dev/${MDDEVICE}
+ return
+ fi
+ fi
+ done
+
+ die "Error: Unable to find unused md device"
+}
+
+#
+# This can be slightly dangerous because it is possible the md devices
+# we are cleaning up may not be ours. However, if the devices are
+# currently in use we will not be able to remove them, and even if
+# we remove devices which were not out we do not zero the super block
+# so you should be able to reconstruct them.
+#
+cleanup_md_devices() {
+ destroy_md_devices "`ls /dev/md* 2>/dev/null | grep -v p`"
+ udev_trigger
+}
+
+#
+# Destroy the passed md devices, this is used when you know
+# the names of the md devices.
+#
+destroy_md_devices() {
+ local MDDEVICES="$1"
+
+ msg "Destroying ${MDDEVICES}"
+ for MDDEVICE in ${MDDEVICES}; do
+ ${MDADM} --stop ${MDDEVICE} &>/dev/null
+ ${MDADM} --remove ${MDDEVICE} &>/dev/null
+ ${MDADM} --detail ${MDDEVICE} &>/dev/null
+ done
+
+ return 0
+}
+
+#
+# Check that the scsi utilities are installed.
+#
+check_sd_utils() {
+ ${INFOMOD} scsi_debug &>/dev/null || die "scsi_debug module required"
+ test -f ${LSSCSI} || die "${LSSCSI} utility must be installed"
+}
+
+#
+# Rescan the scsi bus for scsi_debug devices. It is preferable to use the
+# scsi-rescan tool if it is installed, but if it's not we can fall back to
+# removing and readding the device manually. This rescan will only effect
+# the first scsi_debug device if scsi-rescan is missing.
+#
+scsi_rescan() {
+ local AWK_SCRIPT="/scsi_debug/ { print \$1; exit }"
+
+ if [ -f ${SCSIRESCAN} ]; then
+ ${SCSIRESCAN} --forcerescan --remove &>/dev/null
+ else
+ local SCSIID=`${LSSCSI} | ${AWK} "${AWK_SCRIPT}" | tr -d '[]'`
+ local SCSIHOST=`echo ${SCSIID} | cut -f1 -d':'`
+ echo 1 >"/sys/class/scsi_device/${SCSIID}/device/delete"
+ udev_trigger
+ echo "- - -" >/sys/class/scsi_host/host${SCSIHOST}/scan
+ udev_trigger
+ fi
+}
+
+#
+# Trigger udev and wait for it to settle.
+#
+udev_trigger() {
+ if [ -f ${UDEVADM} ]; then
+ ${UDEVADM} trigger
+ ${UDEVADM} settle
+ else
+ /sbin/udevtrigger
+ /sbin/udevsettle
+ fi
+}
+
+#