NFS Challenges with the NAS

I had my SimpleShare NAS working nicely for a while, but something's changed, and I'm not sure what.

My Debian and Ubuntu machines seem to be using the NAS over NFS as only the nfsnobody (uid -2) user only. The NAS seems to be in all_squash, so I'm creating files, then I'm not able to manipulate or access some of the files. I often can't change permissions either -- operation not permitted. I used to get my regular Linux UIDs on the NAS.

Interestingly, the Mac still has full access to the NAS over NFS, and I have permissions to fix up permissions as necessary.

What's the difference between the Linux client and Mac client, and how'd I break the Linux machine?

Hopefully, I'll be able to report a fix here soon.