Description of problem:

def create_image_minimizer(path, image, compress_type, target_size = None,
                           tmpdir = "/tmp"):
    """
    Builds a copy-on-write image which can be used to
    create a device-mapper snapshot of an image where
    the image's filesystem is as small as possible

    The steps taken are:
      1) Create a sparse COW
      2) Loopback mount the image and the COW
      3) Create a device-mapper snapshot of the image
         using the COW
      4) Resize the filesystem to the minimal size
      5) Determine the amount of space used in the COW
      6) Restroy the device-mapper snapshot
      7) Truncate the COW, removing unused space
      8) Create a squashfs of the COW
    """

Ew.

Instead, to shrink the live filesystem in use, it should just use fstrim(8) from util-linux. Should be much simpler.

Version-Release number of selected component (if applicable):

looking at git