#!/bin/sh
#
# Turn off disk's enclosure slot if it becomes FAULTED.
#
# Bad SCSI disks can often "disappear and reappear" causing all sorts of chaos
# as they flip between FAULTED and ONLINE.  If
# ZED_POWER_OFF_ENCLOUSRE_SLOT_ON_FAULT is set in zed.rc, and the disk gets
# FAULTED, then power down the slot via sysfs:
#
# /sys/class/enclosure/<enclosure>/<slot>/power_status
#
# We assume the user will be responsible for turning the slot back on again.
#
# Note that this script requires that your enclosure be supported by the
# Linux SCSI Enclosure services (SES) driver.  The script will do nothing
# if you have no enclosure, or if your enclosure isn't supported.
#
# Exit codes:
#   0: slot successfully powered off
#   1: enclosure not available
#   2: ZED_POWER_OFF_ENCLOUSRE_SLOT_ON_FAULT disabled
#   3: vdev was not FAULTED
#   4: The enclosure sysfs path passed from ZFS does not exist
#   5: Enclosure slot didn't actually turn off after we told it to

[ -f "${ZED_ZEDLET_DIR}/zed.rc" ] && . "${ZED_ZEDLET_DIR}/zed.rc"
. "${ZED_ZEDLET_DIR}/zed-functions.sh"

if [ ! -d /sys/class/enclosure ] ; then
	# No JBOD enclosure or NVMe slots
	exit 1
fi

if [ "${ZED_POWER_OFF_ENCLOUSRE_SLOT_ON_FAULT}" != "1" ] ; then
	exit 2
fi

if [ "$ZEVENT_VDEV_STATE_STR" != "FAULTED" ] ; then
	exit 3
fi

if [ ! -f "$ZEVENT_VDEV_ENC_SYSFS_PATH/power_status" ] ; then
	exit 4
fi

# Turn off the slot and wait for sysfs to report that the slot is off.
# It can take ~400ms on some enclosures and multiple retries may be needed.
for i in $(seq 1 20) ; do
	echo "off" | tee "$ZEVENT_VDEV_ENC_SYSFS_PATH/power_status"

	for j in $(seq 1 5) ; do
		if [ "$(cat $ZEVENT_VDEV_ENC_SYSFS_PATH/power_status)" == "off" ] ; then
			break 2
		fi
		sleep 0.1
	done
done

if [ "$(cat $ZEVENT_VDEV_ENC_SYSFS_PATH/power_status)" != "off" ] ; then
	exit 5
fi

zed_log_msg "powered down slot $ZEVENT_VDEV_ENC_SYSFS_PATH for $ZEVENT_VDEV_PATH"