I basically downloaded these patches, tried to test them with my samba setup, found they silently didn't work, and discovered it was because we were getting ERANGE.
If you create the hidden/system/whatever file on the Wine side then Samba should pick it up correctly the other direction.
As long as the format has a fixed (or capped) size, which seems to be true of both the Samba 3 and Samba 4 formats, I think it'd make sense to be noisy about ERANGE, since that implies there's a new format we can't parse.
I think that `FIXME_ONCE` might be a better choice here, as you will otherwise get this output for _everything_.
And if not, we should probably be calling it in a loop until we get the whole buffer. Either way, we should complain louder if there's data there that we can't parse.
The sizes are fixed and small, I would think that one read of the maximum supported size makes the most sense.