#!/bin/sh

set -e

SNAP_ID=$1
SNAP_MOUNTPOINT="$2"
SNAP_ORIG_PATH="$5"

CDIR=`dirname $0`

remove_overlay() {
	if test -e "$SNAP_ORIG_PATH/.overlay_2fefd007-3e48-4162-b2c6-45ccdda22f37_$SNAP_ID"
	then
		chattr -i "$SNAP_ORIG_PATH/.overlay_2fefd007-3e48-4162-b2c6-45ccdda22f37_$SNAP_ID"
		rm "$SNAP_ORIG_PATH/.overlay_2fefd007-3e48-4162-b2c6-45ccdda22f37_$SNAP_ID"
	fi
	
	if test -e "$SNAP_ORIG_PATH/.overlay_2fefd007-3e48-4162-b2c6-45ccdda22f37_$SNAP_ID-wsnap"
	then
		LODEV=`losetup -j "$SNAP_ORIG_PATH/.overlay_2fefd007-3e48-4162-b2c6-45ccdda22f37_$SNAP_ID-wsnap" | cut -d':' -f1`
        if [ "x$LODEV" != x ]
        then
            losetup -d "$LODEV"
        fi
		rm "$SNAP_ORIG_PATH/.overlay_2fefd007-3e48-4162-b2c6-45ccdda22f37_$SNAP_ID-wsnap"
	fi
}

remove_dm() {
    if ! [ -e "${SNAP_MOUNTPOINT}-name" ]
    then
        echo "Could not find snapshot device name at ${SNAP_MOUNTPOINT}-name. Cannot remove dm nodes"
        return 1
    fi

    DEVNAME=$(cat "${SNAP_MOUNTPOINT}-name")

    echo "Removing dm snapshot..."

    dmsetup remove "$DEVNAME-$SNAP_ID-wsnap" || true
    dmsetup remove "$DEVNAME-$SNAP_ID" || true

    echo "Removing snapshot cow storage..."
    dmsetup remove "$DEVNAME-$SNAP_ID-cow-storage" || true

    rm "${SNAP_MOUNTPOINT}-name"
    rm "${SNAP_MOUNTPOINT}-dev"
    rmdir "${SNAP_MOUNTPOINT}"
}

if ! test -e $SNAP_MOUNTPOINT
then
    echo "Snapshot at $SNAP_MOUNTPOINT was already removed"
    remove_dm
    remove_overlay
    exit 0
fi

TYPE=$(df -T -P | egrep " ${SNAP_MOUNTPOINT}\$" | head -n 1 | tr -s " " | cut -d" " -f2)

if [ "x$TYPE" = "x" ]
then
        if btrfs subvolume list -o "$SNAP_MOUNTPOINT" > /dev/null 2>&1
        then
                TYPE="btrfs"
        fi
fi

if [ "x$TYPE" = "xbtrfs" ]
then
    $CDIR/btrfs_remove_filesystem_snapshot "$@"
    exit $?
fi

if ! df -T -P | egrep " ${SNAP_MOUNTPOINT}\$" > /dev/null 2>&1
then
    echo "Snapshot is not mounted. Already removed"
    remove_dm
    remove_overlay
    exit 0
fi

if ! [ -e "${SNAP_MOUNTPOINT}-name" ]
then
	echo "Could not find snapshot device name at ${SNAP_MOUNTPOINT}-name"
	exit 1
fi

DEVNAME=$(cat "${SNAP_MOUNTPOINT}-name")

echo "Unmounting /dev/mapper/$DEVNAME-$SNAP_ID at /mnt/urbackup_snaps/$SNAP_ID..."

if ! umount /mnt/urbackup_snaps/$SNAP_ID
then
    lsof | grep /mnt/urbackup_snaps/$SNAP_ID || true
    echo "Unmounting /mnt/urbackup_snaps/$SNAP_ID failed. Retrying in 10s..."
    sleep 10
    umount /mnt/urbackup_snaps/$SNAP_ID
fi

remove_dm
remove_overlay
exit 0