Related to this earlier question I asked, I'd like to know what filesystems will preferentially reuse blocks that are freed when files are deleted (if any exist)?
I am only interested in stable, well-established filesystems and would prefer those that can be the boot/root partition in a Debian system (though this is not essential).
Responding to a comment, I'd like this behaviour because the fs is for a VM and is contained in a sparse raw image file on the host. If new blocks are allocated, the image file gradually loses it's sparseness over time as files are created/deleted/modified, tending towards the 'non-sparse' size, even if the total storage used on the VM remains basically constant.
According to this forum post, "XFS reuses the just freed blocks very fast". Perhaps XFS is the filesystem I am looking for?