nerdctl commit taking long time possibly because of fs.Changes walking through all files

We have an 8GB image we are trying to commit with nerdctl. It takes a long time for this to happen. It seems to be because fs.Changes implemented in continuity is not using the diff functionality from overlayfs but just walking every file.

https://github.com/containerd/continuity/blob/206f576332bc85557835d77bc18166adbe761f4e/fs/diff.go#L101

It seems like this needs to be implemented here:

https://github.com/containerd/continuity/blob/main/fs/diff_unix.go#L34

Could someone please take a look to see if our understanding is correct. If it is, what would it take to fix this code so it can work more effectively for overlayfs?