OpenNebula

When a qcow2 (or any other non-raw image) is downloaded from a remote source, its SIZE is determined from Content-Length. This leads to incorrect SIZE attributes on IMAGEs and breaks resizing. Users are often unknowingly trying to shrink the image (which is not supported by qemu-img).

In `datastore_mad/remotes/libfs.sh`, I can see:

    http://*|https://*)
        HEADERS=`curl -LIk --max-time 60 $1 2>&1`

        if echo "$HEADERS" | grep -i -q "OpenNebula-AppMarket-Size"; then
            # An AppMarket/Marketplace URL
            SIZE=$(echo "$HEADERS" | grep -i "^OpenNebula-AppMarket-Size:" | tail -n1 | cut -d: -f2)
        else
            # Not an AppMarket/Marketplace URL
            SIZE=$(echo "$HEADERS" | grep -i "^Content-Length:" | tail -n1 | cut -d: -f2)
        fi
        error=$?
        ;;

Does this mean that you are using a workaround for OpenNebula Marketplace and setting the correct size without looking at the actual file size?
Are there any plans for getting SIZE after the file is downloaded or, at least, exposing a way to refresh this information later (on registered IMAGEs)?