haarp · August 10, 2024 14:48
diff --git a/backup-zfs b/backup-zfs
 #!/bin/bash
 # ZFS-send backups v1.9.0 :D
 #
 # $1: target device (e.g. `/dev/sdg`) - if omitted, uses udev's $DEVNAME env var instead
 # $2: optional - if existing, assume we're called by udev -> obey inhibit, log to /tmp/backup-zfs_*.log instead of stdout
 # create /tmp/backup-zfs.inhibit to disable automatic udev backups
 # needs udev rule like:
 #   `ACTION=="add", KERNEL=="sd*[!0-9]", ENV{ID_SERIAL}!="?*", SUBSYSTEMS=="usb", RUN+="/usr/bin/setsid --fork /usr/local/bin/backup-zfs $env{DEVNAME} udev"`
 #
 #	status							beep	HP led			Fit-statUSB LED
 #	idle							-		-				-
 #	backup in progress				1		blue perm		blue blink
 #	backup successful				1		magenta perm	green flash/perm	(LED switches off after 4d or on disk removal)
 #	backup disabled/non-backup disk	2		orange flash	yellow flash
 #	backup failed/problems occured	5		orange perm		red perm	(LED switches off after 4d, investigate before removing disk!!)
 #
 # WARNING: Do *not* remove the disk while ZFS is imported, you *will* rape the kernel driver!
 # https://github.com/openzfs/zfs/issues/3461
 # https://github.com/openzfs/zfs/pull/11082#issuecomment-716284367
 #
 # NOTE: This will delete fs not being backed up and all snapshots but the latest on target devices!
 # TODO: Check target health. periodic scrubs?


 # naming prefixes
 SNAP_PREFIX="bzfs"		# snapshots will be created/checked against this
 POOL_PREFIX="backup"	# target pools will be checked against this
 # source pool
 SOURCE="data3"
 # non-recursive:
 EXCLUDES=( "$SOURCE/Downloads" "$SOURCE/MP3" "$SOURCE/Stuff/Low" "$SOURCE/tmp" )
 # how many most recent snapshots to keep on source
 KEEP=10


 auxiliary() {
 	echo -e "\e[43mDoing auxiliary transfers\e[49m"
 	[[ $(/sbin/zfs get -H -o value mounted "$target") == "yes" ]] || /sbin/zfs mount "$target" || { ((uhoh++)); return 1; }

 	echo "/etc/backuppc"
 	rsync -aHAX -h -R --delete "/etc/backuppc" "$(/sbin/zfs get -H -o value mountpoint "$target")"
 }

 beep() {
 	for i in $(seq 1 ${1:-1}); do
 		echo -ne "\a" > /dev/tty31
 		sleep 0.35
 	done
 }
 hp_led() {
 	# args: <off|blue|orange|magenta>
 	# or no args to check if leds exist at all
 	# https://github.com/stupidpupil/hp_n36-40-54l_health_led_drivers
 	# (re)build on new kernel with build_all_debs.sh && sudo dpkg -i dist/*.deb
 	# rmmod i2c_piix4 sp5100_tco; modprobe i2c-piix4; sleep 5; modprobe gpio-sb8xx
 	local blue orange

 	{ base_addr=$(< /sys/class/gpio/gpiochip256/base); } 2>/dev/null
 	[[ $base_addr ]] || return 1

 	case $1 in
 		off)	blue=0
 			orange=0;;
 		blue)	blue=1
 			orange=0;;
 		orange)	blue=0
 			orange=1;;
 		magenta) blue=1
 			orange=1;;
 		*)	return 0;;
 	esac

 	blue_addr=$(( $base_addr + 188 ))
 	orange_addr=$(( $base_addr + 187 ))

 	[[ -e /sys/class/gpio/gpio$blue_addr ]] || echo $blue_addr >/sys/class/gpio/export
 	[[ -e /sys/class/gpio/gpio$orange_addr ]] || echo $orange_addr >/sys/class/gpio/export

 	# invert
 	[[ $blue == 1 ]] && blue=0 || blue=1
 	[[ $orange == 1 ]] && orange=0 || orange=1

 	echo $blue >/sys/class/gpio/gpio$blue_addr/value
 	echo $orange >/sys/class/gpio/gpio$orange_addr/value
 }
 fit_led() {
 	# args: <off|red|green|blue|yellow> [cycle time in ms]
 	# or no args to check if leds exist at all
 	local string

 	local path=$(echo /dev/serial/by-id/usb-Compulab_LTD_fit_StatUSB*)
 	[[ -w $path ]] || return 1

 	case $1 in
 		off)	string="#000000";;
 		red)	string="#200000";;
 		green)	string="#002000";;
 		blue)	string="#000020";;
 		yellow)	string="#200800";;
 		*)	return 0;;
 	esac

 	[[ $2 ]] && string="B$string-$2#000000-$2"

 	stty -F "$path" 9600 raw -echo -echoe -echok -echoctl -echoke
 	echo "$string" >"$path"
 }

 status() {
 	# if no target set yet, show device instead
 	[[ "$target" ]] || local target="${device##*/}"

 	case $1 in
 		inprogress)
 			wall "${0##*/}_$target: Starting backup from $SOURCE"
 			beep 1 &
 			hp_led blue &
 			fit_led blue 750 &
 		;;
 		successful)
 			wall "${0##*/}_$target: Backup finished"
 			beep 1 &
 			hp_led magenta &
 			# flash for a while to indicate SMR possibly still being written
 			fit_led green 1500 &
 			# Switch off led after device is removed or after timeout
 			# TODO: have new instances of this script kill this
 			hp_led && { timeout 4d inotifywait -q -e delete_self "$device"; hp_led off; } &
 			fit_led && { timeout 20m inotifywait -q -e delete_self "$device"; if [[ $? == 124 ]]; then
 				fit_led green
 				timeout 4d inotifywait -q -e delete_self "$device"
 				fit_led off
 			else
 				fit_led off
 			fi; } &
 		;;
 		nobackup)
 			wall "${0##*/}_$target: Not doing backups to this disk"
 			beep 2 &
 			{ hp_led orange; sleep 1; hp_led off; } &
 			{ fit_led yellow; sleep 1; fit_led off; } &
 		;;
 		disabled)
 			wall "${0##*/}_$target: Backups disabled"
 			beep 2 &
 			{ hp_led orange; sleep 1; hp_led off; } &
 			{ fit_led yellow; sleep 1; fit_led off; } &
 		;;
 		failed)
 			if [[ $uhoh > 0 ]]; then
 				wall "${0##*/}_$target: Backup finished with $uhoh problem(s)!"
 			else
 				wall "${0##*/}_$target: Backup failed!"
 			fi
 			beep 5 &
 			hp_led orange &
 			fit_led red &
 			hp_led && { timeout 4d inotifywait -q -e delete_self "$device"; hp_led off; } &
 			fit_led && { timeout 4d inotifywait -q -e delete_self "$device"; fit_led off; } &
 		;;
 	esac
 }

 main() {
 	### findtarget

 	# Check for ZFS on device
 	# FIXME: won't work, empty output. udev hasn't filled this in yet?
 ##	if ! lsblk -n -o FSTYPE "$device" | grep -q 'zfs_member'; then
 ##		echo "No zpool found on $device, exiting."
 ##		status nobackup
 ##		exit 0
 ##	fi

 	# Find pool on device (assumes one pool on device)
 	while [[ ! "$target" ]]; do	# fake loop
 		# look at imported pools
 		# FIXME: fails when pool is already imported but on different device
 		while read d junk; do
 			if [[ ! "$junk" ]]; then
 				# it's a list header, let's look at this pool
 				pool="$d"
 			else
 				if [[ $(readlink -f "$d") =~ $(readlink -f "$device") ]]; then
 					target="$pool"	# previously found pool belongs to our device!
 					break 2
 				fi
 			fi
 		done <<< $(/sbin/zpool list -H -P -o name -v)

 		# look at importable pools
 		for d in $device*; do arg+="-d $d "; done	# scan all partitions on $device
 		target=$(/sbin/zpool import $arg 2>/dev/null | awk '/^ *pool/{print $2}')
 		break
 	done

 	if [[ "$target" == "$SOURCE" ]]; then
 		# did we just boot or import the source pool? don't clobber it!
 		echo "Source and target zpools are the same, exiting."
 		exit 2
 	elif [[ "$target" =~ ^"$POOL_PREFIX" ]]; then
 		# success
 		:
 	elif [[ "$target" ]]; then
 		echo "Target zpool $target doesn't sound like a backup, exiting."
 		status nobackup
 		exit 0	# don't exit >0 if random-ass zfs drive got attached
 	else
 		echo "Couldn't find pool to go with $device!"
 		status nobackup
 		exit 0	# don't exit >0 if random-ass non-zfs drive got attached
 	fi


 	### main-main

 	# Ensure single instance
 	LOCKFILE="/run/${0##*/}_$target.lock"
 	if { kill -0 $(< "$LOCKFILE"); } 2>/dev/null; then
 		echo "Already running, aborting!"
 		exit 1
 	fi
 	echo $$ > "$LOCKFILE"

 	# Sanity check: Would be nice for the source to exist
 	if ! /sbin/zpool list -o name "$SOURCE" &>/dev/null; then
 		echo "Source pool $SOURCE not found, aborting!"
 		status failed
 		exit 1
 	fi

 	echo -e "\e[43mStarting backup\e[49m from \e[45m$SOURCE\e[49m to \e[45m$target\e[49m"
 	status inprogress

 	# Actually do the importing if necessary
 	if ! /sbin/zpool list -o name "$target" &>/dev/null; then
 		echo "Importing pool $target..."
 		/sbin/zpool import -R /mnt "$target" || {
 			status failed
 			exit 1
 		}
 	fi

 	/sbin/zpool status "$target"
 	sleep 3

 	uhoh=0

 	auxiliary

 	fslist=()
 	while read fs; do
 		# Skip excluded fs
 		for e in ${EXCLUDES[@]}; do
 			if [[ "$fs" == "$e" ]]; then
 				##echo -e "\e[44mSkipping $fs\e[49m (excluded)"
 				continue 2
 			fi
 		done

 		fslist+=("$fs")
 	done <<< $(/sbin/zfs list -H -o name -t filesystem,volume -r "$SOURCE")

 	newsnap="${SNAP_PREFIX}_$(date '+%Y-%m-%d')"
 	echo -e "\e[43mCreating snapshots\e[49m $SOURCE@\e[45m$newsnap\e[49m"
 	# concatenate snapshot to array elements so we can still use ${foo[@]} quoting magic with spaces inside fs names
 	/sbin/zfs snapshot "${fslist[@]/%/@$newsnap}"  ##|| ((uhoh++))	# don't uhoh, snapshots might exist already

 	destroy=()

 	echo -e "\e[43mStarting transfers\e[49m"
 	for fs in "${fslist[@]}"; do
 		# Terminal title
 		[[ -t 1 ]] && echo -ne "\033]2;$target/$fs [${0##*/}]\007"

 		# Snapshots present for this fs on source
 		snaps_source=()
 		while IFS='@' read junk snap; do
 			[[ "$snap" =~ ^"${SNAP_PREFIX}"_[0-9-]+$ ]] && snaps_source+=("$snap")
 		done <<< "$(/sbin/zfs list -H -o name -t snapshot -s creation "$fs" 2>/dev/null)"
 		# Remember snapshots to destroy on source later, keeping $KEEP most recent (reverse order because faster)
 		destroy_snaps=""
 		for (( i=$(( ${#snaps_source[@]}-1 - $KEEP )); i>=0; i-- )); do
 			destroy_snaps+="${snaps_source[$i]},"	# only snapshot names may be comma-separated
 		done
 		[[ "$destroy_snaps" ]] && destroy+=("$fs@$destroy_snaps")

 		# Snapshots present for this fs on target
 		snaps_target=()
 		while IFS='@' read junk snap; do
 			[[ "$snap" =~ ^"${SNAP_PREFIX}"_[0-9-]+$ ]] && snaps_target+=("$snap")
 		done <<< "$(/sbin/zfs list -H -o name -t snapshot -s creation "$target/$fs" 2>/dev/null)"
 		# Remember snapshots to destroy on target, but not the one we're about to transfer, if it already exists
 		if [[ "${snaps_target[-1]}" == "$newsnap" ]] 2>/dev/null; then
 			[[ "${snaps_target[-2]}" ]] 2>/dev/null && destroy+=("$target/$fs@%${snaps_target[-2]}")	# % operator denotes range
 		else
 			[[ "${snaps_target[-1]}" ]] 2>/dev/null && destroy+=("$target/$fs@%${snaps_target[-1]}")
 		fi

 		# Find newest common snapshot
 		commonsnap=""
 		for (( i=${#snaps_target[@]}-1; i>=0; i-- )); do
 			# skip fs if planned snapshot already exists
 			if [[ "${snaps_target[$i]}" == "$newsnap" ]]; then
 				echo -e "\e[44mSkipping $fs\e[49m (@\e[45m$newsnap\e[49m already exists on $target)"
 				continue 2
 			fi

 			for snap in "${snaps_source[@]}"; do
 				if [[ "${snaps_target[$i]}" == "$snap" ]]; then
 					commonsnap="${snaps_target[$i]}"
 					break 2
 				fi
 			done
 		done

 		if [[ $commonsnap ]]; then
 			echo -e "\e[42mSending $fs\e[49m (incr from @\e[45m$commonsnap\e[49m to @\e[45m$newsnap\e[49m)"
 			incrparam=("-i" "$fs@$commonsnap")
 		else
 			# gotta destroy it first :/
 			# https://www.reddit.com/r/zfs/comments/dkldqr/having_trouble_using_sendreceive_on_encrypted/
 			# https://www.reddit.com/r/zfs/comments/ja0f5r/backing_up_encrypted_stream/
 			# https://www.reddit.com/r/zfs/comments/u6d3p4/rfc_notes_on_encrypted_zfs_backup_creation_and/i5h082c/
 			/sbin/zfs list "$target/$fs" &>/dev/null && {
 				/sbin/zfs destroy -v -r "$target/$fs"
 				echo "waiting a bit for space to free up..."
 				sleep 120	# this can take *much* longer tho
 			}

 			echo -e "\e[42mSending $fs\e[49m (full @\e[45m$newsnap\e[49m)"
 			incrparam=()
 		fi

 		# `zfs send -P` can mysteriously fail with `warning: cannot send 'foo': Unknown error 1030`, so handle it gracefully
 		size=$(set -o pipefail; /sbin/zfs send -n -P "${incrparam[@]}" "$fs@$newsnap" 2>/dev/null | awk '/^size/{print $2}') || size=0
 		if [[ $size -gt $(/sbin/zpool list -H -p -o free $target) ]]; then
 			echo "Not enough free space, skipping!"
 			((uhoh++))
 			continue
 		fi

 		# Transfer!
 		# always use -L: https://github.com/openzfs/zfs/issues/6224
 		/sbin/zfs send -L -w -p "${incrparam[@]}" "$fs@$newsnap" | pv -s $size -D 0.1 -i 10 | /sbin/zfs receive -F -u "$target/$fs" || ((uhoh++))
 	done

 	# Execute deletion
 	if [[ $uhoh == 0 && "${destroy[@]}" ]]; then
 		echo -e "\e[43mDestroying old snapshots on source and target\e[49m"
 		for d in "${destroy[@]}"; do
 			/sbin/zfs destroy -v "$d"
 		done
 	fi

 	# Delete old/excluded fs on target
 	destroy=()
 	while read tfs; do
 		# skip datasets not in target/source/ tree
 		[[ "$tfs" =~ ^"$target/$SOURCE" ]] || continue

 		# skip datasets subject to backup
 		for sfs in ${fslist[@]}; do
 			if [[ "$tfs" == "$target/$sfs" ]]; then
 				continue 2
 			fi
 		done

 		destroy+=("$tfs")
 	done <<< $(/sbin/zfs list -H -o name -t filesystem,volume -r "$target")
 	# Execute deletion
 	if [[ $uhoh == 0 && "${destroy[@]}" ]]; then
 		echo -e "\e[43mDestroying old/excluded fs on target\e[49m"
 		for d in "${destroy[@]}"; do
 			/sbin/zfs destroy -v -r "$d"
 		done
 	fi

 	echo -e "\e[43mFinishing backup\e[49m"
 	sleep 15	# so `used` below is sorta accurate
 	echo "Elapsed time: ${SECONDS} seconds, $(/sbin/zpool list -H -o alloc "$target")B of $(/sbin/zpool list -H -o size "$target")B in use on $target."

 	[[ -t 1 ]] && {
 		echo -n "Exporting...press Ctrl+c to cancel! "
 		for i in {5..1}; do echo -n "${i}.."; sleep 1; done; echo ""
 	}

 	if /sbin/zpool export "$target"; then
 		sync
 		sleep 5
 		echo "Unmounted and exported."
 		# TODO: have new instances of this script kill this
 		# TODO: query drive for SMR first? nope, Seagate Expansion lies about it... (/sys/block/sdX/device/scsi_disk/*/zoned_cap=none)
 		# Give SMR drives 30min to finish writing from CMR zone, then shut down spindle
 #		{ for i in {1..30}; do [[ -b "$device" ]] || exit; sleep 60; done; /sbin/hdparm -Y "$device"; } &
 	else
 		echo "Unmount/Export failed!"
 		((uhoh++))
 	fi

 	if [[ $uhoh == 0 ]]; then
 		status successful
 	else
 		echo -e "\e[41mThere were $uhoh problem(s)! destroy skipped.\e[49m"
 		status failed
 	fi

 	rm "$LOCKFILE"
 	exit 0
 }


 if [[ -b "$1" ]]; then
 	# device passed
 	device="$1"
 elif [[ "$1" ]]; then
 	echo "Don't know what to do with $1!"
 	exit 1
 else
 	echo "Don't know what to do!"
 	exit 1
 fi

 if [[ "$2" ]]; then
 	# called by udev

 	# bail out if still booting
 	runlevel=$(runlevel)
 	[[ ${runlevel#* } =~ [2-5] ]] || exit 2

 	# obey inhibit
 	if [[ -e "/tmp/backup-zfs.inhibit" ]]; then
 		status disabled
 		exit 0
 	fi

 	# strip colors
 	main 2>&1 | sed --unbuffered -E "s/[[:cntrl:]]\[[0-9]{1,3}m//g" > "/tmp/backup-zfs_$(basename "$device").log"
 else
 	main
 fi
	#!/bin/bash
	# ZFS-send backups v1.9.0 :D
	#
	# $1: target device (e.g. `/dev/sdg`) - if omitted, uses udev's $DEVNAME env var instead
	# $2: optional - if existing, assume we're called by udev -> obey inhibit, log to /tmp/backup-zfs_*.log instead of stdout
	# create /tmp/backup-zfs.inhibit to disable automatic udev backups
	# needs udev rule like:
	# `ACTION=="add", KERNEL=="sd[!0-9]", ENV{ID_SERIAL}!="?", SUBSYSTEMS=="usb", RUN+="/usr/bin/setsid --fork /usr/local/bin/backup-zfs $env{DEVNAME} udev"`
	#
	# status beep HP led Fit-statUSB LED
	# idle - - -
	# backup in progress 1 blue perm blue blink
	# backup successful 1 magenta perm green flash/perm (LED switches off after 4d or on disk removal)
	# backup disabled/non-backup disk 2 orange flash yellow flash
	# backup failed/problems occured 5 orange perm red perm (LED switches off after 4d, investigate before removing disk!!)
	#
	# WARNING: Do not remove the disk while ZFS is imported, you will rape the kernel driver!
	# https://github.com/openzfs/zfs/issues/3461
	# https://github.com/openzfs/zfs/pull/11082#issuecomment-716284367
	#
	# NOTE: This will delete fs not being backed up and all snapshots but the latest on target devices!
	# TODO: Check target health. periodic scrubs?


	# naming prefixes
	SNAP_PREFIX="bzfs" # snapshots will be created/checked against this
	POOL_PREFIX="backup" # target pools will be checked against this
	# source pool
	SOURCE="data3"
	# non-recursive:
	EXCLUDES=( "$SOURCE/Downloads" "$SOURCE/MP3" "$SOURCE/Stuff/Low" "$SOURCE/tmp" )
	# how many most recent snapshots to keep on source
	KEEP=10


	auxiliary() {
	echo -e "\e[43mDoing auxiliary transfers\e[49m"
	[[ $(/sbin/zfs get -H -o value mounted "$target") == "yes" ]] \|\| /sbin/zfs mount "$target" \|\| { ((uhoh++)); return 1; }

	echo "/etc/backuppc"
	rsync -aHAX -h -R --delete "/etc/backuppc" "$(/sbin/zfs get -H -o value mountpoint "$target")"
	}

	beep() {
	for i in $(seq 1 ${1:-1}); do
	echo -ne "\a" > /dev/tty31
	sleep 0.35
	done
	}
	hp_led() {
	# args: <off\|blue\|orange\|magenta>
	# or no args to check if leds exist at all
	# https://github.com/stupidpupil/hp_n36-40-54l_health_led_drivers
	# (re)build on new kernel with build_all_debs.sh && sudo dpkg -i dist/*.deb
	# rmmod i2c_piix4 sp5100_tco; modprobe i2c-piix4; sleep 5; modprobe gpio-sb8xx
	local blue orange

	{ base_addr=$(< /sys/class/gpio/gpiochip256/base); } 2>/dev/null
	[[ $base_addr ]] \|\| return 1

	case $1 in
	off) blue=0
	orange=0;;
	blue) blue=1
	orange=0;;
	orange) blue=0
	orange=1;;
	magenta) blue=1
	orange=1;;
	*) return 0;;
	esac

	blue_addr=$(( $base_addr + 188 ))
	orange_addr=$(( $base_addr + 187 ))

	[[ -e /sys/class/gpio/gpio$blue_addr ]] \|\| echo $blue_addr >/sys/class/gpio/export
	[[ -e /sys/class/gpio/gpio$orange_addr ]] \|\| echo $orange_addr >/sys/class/gpio/export

	# invert
	[[ $blue == 1 ]] && blue=0 \|\| blue=1
	[[ $orange == 1 ]] && orange=0 \|\| orange=1

	echo $blue >/sys/class/gpio/gpio$blue_addr/value
	echo $orange >/sys/class/gpio/gpio$orange_addr/value
	}
	fit_led() {
	# args: <off\|red\|green\|blue\|yellow> [cycle time in ms]
	# or no args to check if leds exist at all
	local string

	local path=$(echo /dev/serial/by-id/usb-Compulab_LTD_fit_StatUSB*)
	[[ -w $path ]] \|\| return 1

	case $1 in
	off) string="#000000";;
	red) string="#200000";;
	green) string="#002000";;
	blue) string="#000020";;
	yellow) string="#200800";;
	*) return 0;;
	esac

	[[ $2 ]] && string="B$string-$2#000000-$2"

	stty -F "$path" 9600 raw -echo -echoe -echok -echoctl -echoke
	echo "$string" >"$path"
	}

	status() {
	# if no target set yet, show device instead
	[[ "$target" ]] \|\| local target="${device##*/}"

	case $1 in
	inprogress)
	wall "${0##*/}_$target: Starting backup from $SOURCE"
	beep 1 &
	hp_led blue &
	fit_led blue 750 &
	;;
	successful)
	wall "${0##*/}_$target: Backup finished"
	beep 1 &
	hp_led magenta &
	# flash for a while to indicate SMR possibly still being written
	fit_led green 1500 &
	# Switch off led after device is removed or after timeout
	# TODO: have new instances of this script kill this
	hp_led && { timeout 4d inotifywait -q -e delete_self "$device"; hp_led off; } &
	fit_led && { timeout 20m inotifywait -q -e delete_self "$device"; if [[ $? == 124 ]]; then
	fit_led green
	timeout 4d inotifywait -q -e delete_self "$device"
	fit_led off
	else
	fit_led off
	fi; } &
	;;
	nobackup)
	wall "${0##*/}_$target: Not doing backups to this disk"
	beep 2 &
	{ hp_led orange; sleep 1; hp_led off; } &
	{ fit_led yellow; sleep 1; fit_led off; } &
	;;
	disabled)
	wall "${0##*/}_$target: Backups disabled"
	beep 2 &
	{ hp_led orange; sleep 1; hp_led off; } &
	{ fit_led yellow; sleep 1; fit_led off; } &
	;;
	failed)
	if [[ $uhoh > 0 ]]; then
	wall "${0##*/}_$target: Backup finished with $uhoh problem(s)!"
	else
	wall "${0##*/}_$target: Backup failed!"
	fi
	beep 5 &
	hp_led orange &
	fit_led red &
	hp_led && { timeout 4d inotifywait -q -e delete_self "$device"; hp_led off; } &
	fit_led && { timeout 4d inotifywait -q -e delete_self "$device"; fit_led off; } &
	;;
	esac
	}

	main() {
	### findtarget

	# Check for ZFS on device
	# FIXME: won't work, empty output. udev hasn't filled this in yet?
	## if ! lsblk -n -o FSTYPE "$device" \| grep -q 'zfs_member'; then
	## echo "No zpool found on $device, exiting."
	## status nobackup
	## exit 0
	## fi

	# Find pool on device (assumes one pool on device)
	while [[ ! "$target" ]]; do # fake loop
	# look at imported pools
	# FIXME: fails when pool is already imported but on different device
	while read d junk; do
	if [[ ! "$junk" ]]; then
	# it's a list header, let's look at this pool
	pool="$d"
	else
	if [[ $(readlink -f "$d") =~ $(readlink -f "$device") ]]; then
	target="$pool" # previously found pool belongs to our device!
	break 2
	fi
	fi
	done <<< $(/sbin/zpool list -H -P -o name -v)

	# look at importable pools
	for d in $device*; do arg+="-d $d "; done # scan all partitions on $device
	target=$(/sbin/zpool import $arg 2>/dev/null \| awk '/^ *pool/{print $2}')
	break
	done

	if [[ "$target" == "$SOURCE" ]]; then
	# did we just boot or import the source pool? don't clobber it!
	echo "Source and target zpools are the same, exiting."
	exit 2
	elif [[ "$target" =~ ^"$POOL_PREFIX" ]]; then
	# success
	:
	elif [[ "$target" ]]; then
	echo "Target zpool $target doesn't sound like a backup, exiting."
	status nobackup
	exit 0 # don't exit >0 if random-ass zfs drive got attached
	else
	echo "Couldn't find pool to go with $device!"
	status nobackup
	exit 0 # don't exit >0 if random-ass non-zfs drive got attached
	fi


	### main-main

	# Ensure single instance
	LOCKFILE="/run/${0##*/}_$target.lock"
	if { kill -0 $(< "$LOCKFILE"); } 2>/dev/null; then
	echo "Already running, aborting!"
	exit 1
	fi
	echo $$ > "$LOCKFILE"

	# Sanity check: Would be nice for the source to exist
	if ! /sbin/zpool list -o name "$SOURCE" &>/dev/null; then
	echo "Source pool $SOURCE not found, aborting!"
	status failed
	exit 1
	fi

	echo -e "\e[43mStarting backup\e[49m from \e[45m$SOURCE\e[49m to \e[45m$target\e[49m"
	status inprogress

	# Actually do the importing if necessary
	if ! /sbin/zpool list -o name "$target" &>/dev/null; then
	echo "Importing pool $target..."
	/sbin/zpool import -R /mnt "$target" \|\| {
	status failed
	exit 1
	}
	fi

	/sbin/zpool status "$target"
	sleep 3

	uhoh=0

	auxiliary

	fslist=()
	while read fs; do
	# Skip excluded fs
	for e in ${EXCLUDES[@]}; do
	if [[ "$fs" == "$e" ]]; then
	##echo -e "\e[44mSkipping $fs\e[49m (excluded)"
	continue 2
	fi
	done

	fslist+=("$fs")
	done <<< $(/sbin/zfs list -H -o name -t filesystem,volume -r "$SOURCE")

	newsnap="${SNAP_PREFIX}_$(date '+%Y-%m-%d')"
	echo -e "\e[43mCreating snapshots\e[49m $SOURCE@\e[45m$newsnap\e[49m"
	# concatenate snapshot to array elements so we can still use ${foo[@]} quoting magic with spaces inside fs names
	/sbin/zfs snapshot "${fslist[@]/%/@$newsnap}" ##\|\| ((uhoh++)) # don't uhoh, snapshots might exist already

	destroy=()

	echo -e "\e[43mStarting transfers\e[49m"
	for fs in "${fslist[@]}"; do
	# Terminal title
	[[ -t 1 ]] && echo -ne "\033]2;$target/$fs [${0##*/}]\007"

	# Snapshots present for this fs on source
	snaps_source=()
	while IFS='@' read junk snap; do
	[[ "$snap" =~ ^"${SNAP_PREFIX}"_[0-9-]+$ ]] && snaps_source+=("$snap")
	done <<< "$(/sbin/zfs list -H -o name -t snapshot -s creation "$fs" 2>/dev/null)"
	# Remember snapshots to destroy on source later, keeping $KEEP most recent (reverse order because faster)
	destroy_snaps=""
	for (( i=$(( ${#snaps_source[@]}-1 - $KEEP )); i>=0; i-- )); do
	destroy_snaps+="${snaps_source[$i]}," # only snapshot names may be comma-separated
	done
	[[ "$destroy_snaps" ]] && destroy+=("$fs@$destroy_snaps")

	# Snapshots present for this fs on target
	snaps_target=()
	while IFS='@' read junk snap; do
	[[ "$snap" =~ ^"${SNAP_PREFIX}"_[0-9-]+$ ]] && snaps_target+=("$snap")
	done <<< "$(/sbin/zfs list -H -o name -t snapshot -s creation "$target/$fs" 2>/dev/null)"
	# Remember snapshots to destroy on target, but not the one we're about to transfer, if it already exists
	if [[ "${snaps_target[-1]}" == "$newsnap" ]] 2>/dev/null; then
	[[ "${snaps_target[-2]}" ]] 2>/dev/null && destroy+=("$target/$fs@%${snaps_target[-2]}") # % operator denotes range
	else
	[[ "${snaps_target[-1]}" ]] 2>/dev/null && destroy+=("$target/$fs@%${snaps_target[-1]}")
	fi

	# Find newest common snapshot
	commonsnap=""
	for (( i=${#snaps_target[@]}-1; i>=0; i-- )); do
	# skip fs if planned snapshot already exists
	if [[ "${snaps_target[$i]}" == "$newsnap" ]]; then
	echo -e "\e[44mSkipping $fs\e[49m (@\e[45m$newsnap\e[49m already exists on $target)"
	continue 2
	fi

	for snap in "${snaps_source[@]}"; do
	if [[ "${snaps_target[$i]}" == "$snap" ]]; then
	commonsnap="${snaps_target[$i]}"
	break 2
	fi
	done
	done

	if [[ $commonsnap ]]; then
	echo -e "\e[42mSending $fs\e[49m (incr from @\e[45m$commonsnap\e[49m to @\e[45m$newsnap\e[49m)"
	incrparam=("-i" "$fs@$commonsnap")
	else
	# gotta destroy it first :/
	# https://www.reddit.com/r/zfs/comments/dkldqr/having_trouble_using_sendreceive_on_encrypted/
	# https://www.reddit.com/r/zfs/comments/ja0f5r/backing_up_encrypted_stream/
	# https://www.reddit.com/r/zfs/comments/u6d3p4/rfc_notes_on_encrypted_zfs_backup_creation_and/i5h082c/
	/sbin/zfs list "$target/$fs" &>/dev/null && {
	/sbin/zfs destroy -v -r "$target/$fs"
	echo "waiting a bit for space to free up..."
	sleep 120 # this can take much longer tho
	}

	echo -e "\e[42mSending $fs\e[49m (full @\e[45m$newsnap\e[49m)"
	incrparam=()
	fi

	# `zfs send -P` can mysteriously fail with `warning: cannot send 'foo': Unknown error 1030`, so handle it gracefully
	size=$(set -o pipefail; /sbin/zfs send -n -P "${incrparam[@]}" "$fs@$newsnap" 2>/dev/null \| awk '/^size/{print $2}') \|\| size=0
	if [[ $size -gt $(/sbin/zpool list -H -p -o free $target) ]]; then
	echo "Not enough free space, skipping!"
	((uhoh++))
	continue
	fi

	# Transfer!
	# always use -L: https://github.com/openzfs/zfs/issues/6224
	/sbin/zfs send -L -w -p "${incrparam[@]}" "$fs@$newsnap" \| pv -s $size -D 0.1 -i 10 \| /sbin/zfs receive -F -u "$target/$fs" \|\| ((uhoh++))
	done

	# Execute deletion
	if [[ $uhoh == 0 && "${destroy[@]}" ]]; then
	echo -e "\e[43mDestroying old snapshots on source and target\e[49m"
	for d in "${destroy[@]}"; do
	/sbin/zfs destroy -v "$d"
	done
	fi

	# Delete old/excluded fs on target
	destroy=()
	while read tfs; do
	# skip datasets not in target/source/ tree
	[[ "$tfs" =~ ^"$target/$SOURCE" ]] \|\| continue

	# skip datasets subject to backup
	for sfs in ${fslist[@]}; do
	if [[ "$tfs" == "$target/$sfs" ]]; then
	continue 2
	fi
	done

	destroy+=("$tfs")
	done <<< $(/sbin/zfs list -H -o name -t filesystem,volume -r "$target")
	# Execute deletion
	if [[ $uhoh == 0 && "${destroy[@]}" ]]; then
	echo -e "\e[43mDestroying old/excluded fs on target\e[49m"
	for d in "${destroy[@]}"; do
	/sbin/zfs destroy -v -r "$d"
	done
	fi

	echo -e "\e[43mFinishing backup\e[49m"
	sleep 15 # so `used` below is sorta accurate
	echo "Elapsed time: ${SECONDS} seconds, $(/sbin/zpool list -H -o alloc "$target")B of $(/sbin/zpool list -H -o size "$target")B in use on $target."

	[[ -t 1 ]] && {
	echo -n "Exporting...press Ctrl+c to cancel! "
	for i in {5..1}; do echo -n "${i}.."; sleep 1; done; echo ""
	}

	if /sbin/zpool export "$target"; then
	sync
	sleep 5
	echo "Unmounted and exported."
	# TODO: have new instances of this script kill this
	# TODO: query drive for SMR first? nope, Seagate Expansion lies about it... (/sys/block/sdX/device/scsi_disk/*/zoned_cap=none)
	# Give SMR drives 30min to finish writing from CMR zone, then shut down spindle
	# { for i in {1..30}; do [[ -b "$device" ]] \|\| exit; sleep 60; done; /sbin/hdparm -Y "$device"; } &
	else
	echo "Unmount/Export failed!"
	((uhoh++))
	fi

	if [[ $uhoh == 0 ]]; then
	status successful
	else
	echo -e "\e[41mThere were $uhoh problem(s)! destroy skipped.\e[49m"
	status failed
	fi

	rm "$LOCKFILE"
	exit 0
	}


	if [[ -b "$1" ]]; then
	# device passed
	device="$1"
	elif [[ "$1" ]]; then
	echo "Don't know what to do with $1!"
	exit 1
	else
	echo "Don't know what to do!"
	exit 1
	fi

	if [[ "$2" ]]; then
	# called by udev

	# bail out if still booting
	runlevel=$(runlevel)
	[[ ${runlevel#* } =~ [2-5] ]] \|\| exit 2

	# obey inhibit
	if [[ -e "/tmp/backup-zfs.inhibit" ]]; then
	status disabled
	exit 0
	fi

	# strip colors
	main 2>&1 \| sed --unbuffered -E "s/[[:cntrl:]]\[[0-9]{1,3}m//g" > "/tmp/backup-zfs_$(basename "$device").log"
	else
	main
	fi