HAOS virtiofs hack

80-dlitz-mount-virtiofs.rules

# dlitz 2025
ACTION!="remove", DRIVER=="virtiofs", RUN{program}+="/etc/udev/rules.d/dlitz-mount-virtiofs %n"

README.md

This is meant more for reading & understanding than for running as-is.

Basically put this in a folder on the host, and set up a virtiofs filesystem on the VM pointing to that folder. If the tag name is "localdata", then do mkdir /mnt/localdata ; mount -t virtiofs localdata /mnt/localdata and then run /mnt/localdata/install-rules.sh to install the udev rule into HAOS.

dlitz-mount-virtiofs

#!/bin/sh
# dlitz 2025
set -eux
number="$1"
tag=$(cat "/sys/fs/virtiofs/${number}/tag")

case "$tag" in
#    backup|media|share|ssl)
#       mntpt=/mnt/data/supervisor/"$tag"
#       run_script=
#        ;;
    localdata)
        mntpt=/mnt/data/"$tag"
        run_script=1
        ;;
    *)
        exit 0
        ;;
esac

rc=0
systemd-run -u "dlitz-mount-virtiofs-run@${tag}.service" --slice-inherit --wait --quiet --collect \
    mount --onlyonce -t virtiofs "$tag" "$mntpt" -o rw || rc=$?

if ! ( [ "$rc" -eq 32 ] && mountpoint -q "$mntpt" ); then
    exit "$rc"
fi

if [ "${run_script:+1}" ] && [ -x "$mntpt/postmount" ]; then
        systemd-run -u "dlitz-mount-virtiofs-postmount@${tag}.service" --slice-inherit --wait --quiet --collect \
             /usr/bin/env "number=$number" "tag=$tag" "mntpt=$mntpt" "$mntpt/postmount"
fi

install-rules.sh

#!/bin/sh
# dlitz 2025
set -eu
if ! test -e /mnt/data/supervisor; then
    echo >&2 "error: This should be run inside the HaOS image."
    exit 1
fi

cp -av 80-dlitz-mount-virtiofs.rules dlitz-mount-virtiofs /etc/udev/rules.d/

postmount

#!/bin/sh
# dlitz 2025
# Performs bind mounts after the virtiofs is mounted
set -eux

run_cmd() {
    if [ "$tag" != "localdata" ]; then
        echo >&2 "would run: $*"
    else
        "$@"
    fi
}

umask 022

# Edit these to be whatever makes sense for you.
for d in \
        "addons/local" \
        "addons/data/5c53de3b_esphome" \
        "backup" \
        "media" \
        "share" \
        "ssl" \
        "homeassistant/blueprints" \
        "homeassistant/esphome" \
        "homeassistant/local" \
        "homeassistant/www/local" \
; do
    run_cmd mkdir -m000 -p /mnt/data/supervisor/"$d"
    run_cmd mount --onlyonce --bind "$mntpt/$d" /mnt/data/supervisor/"$d" || true
done

for f in \
    homeassistant/configuration.yaml \
    homeassistant/secrets.yaml \
; do
    if ! [ -e "/mnt/data/supervisor/$f" ]; then
        run_cmd touch /mnt/data/supervisor/"$f"
    fi
    run_cmd mount --onlyonce --bind "$mntpt/$f" /mnt/data/supervisor/"$f" || true
done