We're seeing a case in bootc where the deferred hardlink processing is failing on a particular layer.

The layer in question is over 10G ($reasons) so that was really unwieldly to debug. I ended up writing this https://gist.github.com/cgwalters/f9e9afcc8d94572554184c3b2d5b054e which trims down the layer to a mere 200M. I'm going to try minimizing it here further, but I now have it at least so

```
$ ostree commit --fsync=false -b test --tree=tar=meta.tar
```

reliably fails. Will update this issue.