umount.sh

#!/bin/bash

# umount.sh - Unmount a disk image mounted with mount.sh
# Usage: ./umount.sh [mount_point]

set -e

if [ "$EUID" -ne 0 ]; then
    echo "Error: This script must be run as root"
    exit 1
fi

MOUNT_POINT="${1:-/mnt/img}"

if [ ! -d "$MOUNT_POINT" ]; then
    echo "Error: Mount point '$MOUNT_POINT' not found"
    exit 1
fi

# Find the loop device associated with the mount point
LOOP_DEV=$(findmnt -n -o SOURCE "$MOUNT_POINT" | grep -o '/dev/loop[0-9]*' | head -1)

if [ -z "$LOOP_DEV" ]; then
    echo "Error: Could not find loop device for mount point '$MOUNT_POINT'"
    echo "Attempting recursive unmount anyway..."
    umount -R "$MOUNT_POINT" || true
    exit 1
fi

MAPPER_DEV="/dev/mapper/$(basename $LOOP_DEV)"

echo "==> Unmounting all filesystems recursively from $MOUNT_POINT..."
umount -R "$MOUNT_POINT"

echo "==> Removing partition mappings..."
kpartx -d "$LOOP_DEV"

echo "==> Detaching loop device $LOOP_DEV..."
losetup -d "$LOOP_DEV"

echo "==> Removing mapper symlink $MAPPER_DEV..."
unlink "$MAPPER_DEV" 2>/dev/null || true

echo ""
echo "==> Successfully unmounted!"
echo "    Mount point: $MOUNT_POINT"
echo "    Loop device: $LOOP_DEV (detached)"