mirror_zfs/cmd/zed/zed.d/statechange-led.sh
Christopher Voltz 100790a8dd Retry setting LED
If the LED is being accessed by another process when we try to update
it, the update will be lost. Add a retry loop which will read the state
of the LED and update it until the LED is in the correct state. The
number of times this will occur is limited to ensure that the ZEDlet
won't hang ZED.

Refactor to remove duplication so setting of the LED occurs in only one
place.

Cleanup a couple of the warnings generated by shellcheck which weren't
the result of specific choices by the author. Several notes and warnings
are still present but removing them would make the code less clear or
require adding lines to tell shellcheck to ignore the warning.

Remove ",i" from the documentation at the top of the file which appears
to be a typographic error.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Christopher Voltz <christopher.voltz@hpe.com>
Closes #5795
2017-02-16 13:41:48 -08:00

164 lines
4.2 KiB
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#!/bin/bash
#
# Turn off/on the VDEV's enclosure fault LEDs when the pool's state changes.
#
# Turn the VDEV's fault LED on if it becomes FAULTED, DEGRADED or UNAVAIL.
# Turn the LED off when it's back ONLINE again.
#
# This script run in two basic modes:
#
# 1. If $ZEVENT_VDEV_ENC_SYSFS_PATH and $ZEVENT_VDEV_STATE_STR are set, then
# only set the LED for that particular VDEV. This is the case for statechange
# events and some vdev_* events.
#
# 2. If those vars are not set, then check the state of all VDEVs in the pool
# and set the LEDs accordingly. This is the case for pool_import events.
#
# 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: enclosure led successfully set
# 1: enclosure leds not not available
# 2: enclosure leds administratively disabled
# 3: The led sysfs path passed from ZFS does not exist
# 4: $ZPOOL not set
[ -f "${ZED_ZEDLET_DIR}/zed.rc" ] && . "${ZED_ZEDLET_DIR}/zed.rc"
. "${ZED_ZEDLET_DIR}/zed-functions.sh"
if [ ! -d /sys/class/enclosure ] ; then
exit 1
fi
if [ "${ZED_USE_ENCLOSURE_LEDS}" != "1" ] ; then
exit 2
fi
zed_check_cmd "$ZPOOL" || exit 4
# Global used in set_led debug print
vdev=""
# check_and_set_led (file, val)
#
# Read an enclosure sysfs file, and write it if it's not already set to 'val'
#
# Arguments
# file: sysfs file to set (like /sys/class/enclosure/0:0:1:0/SLOT 10/fault)
# val: value to set it to
#
# Return
# 0 on success, 3 on missing sysfs path
#
function check_and_set_led
{
file="$1"
val="$2"
if [ ! -e "$file" ] ; then
return 3
fi
# If another process is accessing the LED when we attempt to update it,
# the update will be lost so retry until the LED actually changes or we
# timeout.
for _ in $(seq 1 5); do
# We want to check the current state first, since writing to the
# 'fault' entry always always causes a SES command, even if the
# current state is already what you want.
current=$(cat "${file}")
# On some enclosures if you write 1 to fault, and read it back,
# it will return 2. Treat all non-zero values as 1 for
# simplicity.
if [ "$current" != "0" ] ; then
current=1
fi
if [ "$current" != "$val" ] ; then
echo "$val" > "$file"
zed_log_msg "vdev $vdev set '$file' LED to $val"
else
break
fi
done
}
function state_to_val {
state="$1"
if [ "$state" == "FAULTED" ] || [ "$state" == "DEGRADED" ] || \
[ "$state" == "UNAVAIL" ] ; then
echo 1
elif [ "$state" == "ONLINE" ] ; then
echo 0
fi
}
# process_pool ([pool])
#
# Iterate through a pool (or pools) and set the VDEV's enclosure slot LEDs to
# the VDEV's state.
#
# Arguments
# pool: Optional pool name. If not specified, iterate though all pools.
#
# Return
# 0 on success, 3 on missing sysfs path
#
function process_pool
{
pool="$1"
rc=0
# Lookup all the current LED values and paths in parallel
cmd='echo led_token=$(cat "$VDEV_ENC_SYSFS_PATH/fault"),"$VDEV_ENC_SYSFS_PATH",'
out=$($ZPOOL status -vc "$cmd" "$pool" | grep 'led_token=')
while read -r vdev state read write chksum therest ; do
# Read out current LED value and path
tmp=$(echo "$therest" | sed 's/^.*led_token=//g')
IFS="," read -r current_val vdev_enc_sysfs_path <<< "$tmp"
if [ -z "$vdev_enc_sysfs_path" ] ; then
# Skip anything with no sysfs LED entries
continue
fi
if [ ! -e "$vdev_enc_sysfs_path/fault" ] ; then
rc=1
zed_log_msg "vdev $vdev '$file/fault' doesn't exist"
continue;
fi
val=$(state_to_val "$state")
if [ "$current_val" == "$val" ] ; then
# LED is already set correctly
continue;
fi
check_and_set_led "$vdev_enc_sysfs_path/fault" "$val"
(( rc |= $? ))
done <<< "$out"
if [ "$rc" == "0" ] ; then
return 0
else
# We didn't see a sysfs entry that we wanted to set
return 3
fi
}
if [ ! -z "$ZEVENT_VDEV_ENC_SYSFS_PATH" ] && [ ! -z "$ZEVENT_VDEV_STATE_STR" ] ; then
# Got a statechange for an individual VDEV
val=$(state_to_val "$ZEVENT_VDEV_STATE_STR")
vdev="$(basename $ZEVENT_VDEV_PATH)"
check_and_set_led "$ZEVENT_VDEV_ENC_SYSFS_PATH/fault" "$val"
else
# Process the entire pool
process_pool "$(zed_guid_to_pool $ZEVENT_POOL_GUID)"
fi