I’m having the same issue. I’ve installed urbackup in docker container on Synology NAS. I’ve tried everything from umount to see if it was mount with no success and even changed the permissions or at least I tried to and it still no go. I had found some where someone had created a nuke.sh, but even that didn’t work
#!/bin/sh
set -e
dir="$1"
if [ -z “$dir” ]; then
{
echo ‘This script is for destroying old /var/lib/docker directories more safely than’
echo ’ “rm -rf”, which can cause data loss or other serious issues.’
echo
echo “usage: $0 directory”
echo " ie: $0 /var/lib/docker"
} >&2
exit 1
fi
if [ “$(id -u)” != 0 ]; then
echo >&2 “error: $0 must be run as root”
exit 1
fi
if [ ! -d “$dir” ]; then
echo >&2 “error: $dir is not a directory”
exit 1
fi
dir="$(readlink -f “$dir”)"
echo
echo “Nuking $dir …”
echo ’ (if this is wrong, press Ctrl+C NOW!)’
echo
( set -x; sleep 10 )
echo
dir_in_dir() {
inner="$1"
outer="$2"
[ “${inner#$outer}” != “$inner” ]
}
let’s start by unmounting any submounts in $dir
(like -v /home:… for example - DON’T DELETE MY HOME DIRECTORY BRU!)
for mount in $(awk ‘{ print $5 }’ /proc/self/mountinfo); do
mount="$(readlink -f “$mount” || true)"
if dir_in_dir “$mount” “$dir”; then
( set -x; umount -f “$mount” )
fi
done
now, let’s go destroy individual btrfs subvolumes, if any exist
if command -v btrfs > /dev/null 2>&1; then
root="$(df “$dir” | awk ‘NR>1 { print $NF }’)"
root="${root#/}" # if root is “/”, we want it to become “”
for subvol in $(btrfs subvolume list -o “$root/” 2>/dev/null | awk -F’ path ’ ‘{ print $2 }’ | sort -r); do
subvolDir="$root/$subvol"
if dir_in_dir “$subvolDir” “$dir”; then
( set -x; btrfs subvolume delete “$subvolDir” )
fi
done
fi
finally, DESTROY ALL THINGS
( set -x; rm -rf “$dir” )