zfsonlinux/debian/tree/zfsutils-linux/usr/lib/zfs-linux/trim

#!/bin/sh -u

# directly exit successfully when zfs module is not loaded
if ! [ -d /sys/module/zfs ]; then
	exit 0
fi

# [auto] / enable / disable
PROPERTY_NAME="org.debian:periodic-trim"

get_property () {
	# Detect the ${PROPERTY_NAME} property on a given pool.
	# We are abusing user-defined properties on the root dataset,
	# since they're not available on pools https://github.com/openzfs/zfs/pull/11680
	# TODO: use zpool user-defined property when such feature is available.
	pool="$1"
	zfs get -H -o value "${PROPERTY_NAME}" "${pool}" 2>/dev/null
}

trim_if_not_already_trimming () {
	pool="$1"
	if ! zpool status "${pool}" | grep -q "trimming"; then
		# This will error on HDD-only pools: doesn't matter
		zpool trim "${pool}"
	fi
}

# Walk up the kernel parent names:
# this will catch devices from LVM &a.
get_transp () {
	dev="$1"
	while pd="$(lsblk -dnr -o PKNAME "$dev")"; do
		if [ -z "$pd" ]; then
			break
		else
			dev="/dev/$pd"
		fi
	done
	lsblk -dnr -o TRAN "$dev"
}

pool_is_nvme_only () {
	pool="$1"
	# get a list of devices attached to the specified pool
	zpool list -vHP "${pool}" | \
		awk -F'\t' '$2 ~ "^/dev/" {print $2}' | \
	while read -r dev
	do
		[ "$(get_transp "$dev")" = "nvme" ] || return
	done
}

# TRIM all healthy pools that are not already trimming as per their configs.
zpool list -H -o health,name 2>&1 | \
	awk -F'\t' '$1 == "ONLINE" {print $2}' | \
while read -r pool
do
	# read user-defined config
	ret=$(get_property "${pool}") || continue
	case "${ret}" in
		disable);;
		enable)	trim_if_not_already_trimming "${pool}" ;;
		-|auto)	pool_is_nvme_only "${pool}" && trim_if_not_already_trimming "${pool}" ;;
		*)	cat > /dev/stderr <<EOF
$0: [WARNING] illegal value "${ret}" for property "${PROPERTY_NAME}" of ZFS dataset "${pool}".
$0: Acceptable choices for this property are: auto, enable, disable. The default is auto.
EOF
	esac
done