#!/bin/sh
file="$1"
file="$(readlink -f "$file")"
dir="$file"
dev=

while [ -n "$dir" ] && [ -z "$dev" ]; do
	dev=$(awk -vd="$dir" '{if($2 == d && substr($1, 1, 1) == "/")print $1}' </proc/mounts)
	if [ "x$dir" = "x/" ]; then
		break
	fi
	dir="${dir%/*}"
	[ -n "$dir" ] || dir=/

done

if [ -n "$dev" ]; then
	debugfs -R "stat $file" "$dev"
else
	echo "No device found for $file" >&2
fi