User:Jketreno/meego-image-resize

#!/bin/bash
TARGET=$1
[ -z ${TARGET} ] && die "Usage: $0 meego-image.bin [size in M]"
shift
SIZE=$1
[ -z ${SIZE} ] && SIZE=7600

function die {
	echo $@
	exit -1
}

function unhook {
	local path=$1
	[ -e "${path}" ] && {
		mount | grep -q "${PWD}/${path}" && {
			sudo umount "${path}" || die "Unable to unmount '${path}'"
		}
		rmdir "${path}" || die "Unable to rmdir '${path}'"
	}
	return 0
}

function hook {
	local path=$1
	local image=$2
	unhook "${path}"
	mkdir "${path}" || die "Unable to create directory '${path}'"
	local VALUE=($(echo -ne "u b\np\nq\n" | parted "${image}" | grep primary))
	local OFFSET=${VALUE[1]/B}
	sudo mount -o loop,offset=${OFFSET} "${image}" "${path}" ||
		die "Unable to mount '${image}' to '${path}'"
	return 0
}

function resize {
	local image=$1
	local size=$2
	local tmp=($(du --apparent-size -B $((1024*1024)) "${image}"))
	local current="${tmp[0]}"
	[ "${current}" != "${size}" ] && {
		echo -n "Settting '${image}' to ${size}M..."
		dd if=/dev/zero of=${image} bs=1M seek=$((size - 1)) count=1 > /dev/null
		local VALUE=($(echo -ne "u b\np\nq\n" | parted "${image}" | grep btrfs\$))
		[ -z "${VALUE[0]}" ] && die "$0 only supports BTRFS images"
		local OFFSET=${VALUE[1]/B}
		echo -e "rm 1\nmkpart primary btrfs ${OFFSET}b -1\nq" | parted "${image}" > /dev/null
		echo "done"
	}

	return 0
}

resize "${TARGET}" 7600

echo -n "Finalizing image resize..."
TMP=.tmp-resize
hook ${TMP} "${TARGET}"
sudo btrfsctl -r ${SIZE}M -A $(mount | sed -ne "s,^\([^ ]*\) .*${PWD}/${TMP}.*$,\1,p")
unhook ${TMP}
echo "done"