Re: knfsd and FS_REQUIRES_DEV

[Neil Brown]

On Tuesday December 11, [e-mail] wrote:
> I'm not worried about problems where files mysteriously disappear due to
> me screwing up inode numbers in my code, only about causing kernel panics
> or other Bad Things in the server's kernel. If I were to remove the
> FS_REQUIRES_DEV check (or, more likely, submit a patch adding an nfsd
> module option to remove the check...), what are the worst things that
> could theoretically and realistically happen?

If you just removed the check, the worst that would happen is that
after a server reboot you have to remount everything on your clients.

If you submit a patch to make it an option, the worst that can happen
is that I jump on you (but I'm not a good long jumper, so you are
pretty safe).

I plan to make a change to knfsd in the near future so that you can
have an option like:
   fs=27
in /etc/exports and the the kernel puts the magic number "27" in the
filehandle instead of the device number.  Then as long as you export
each filesystem with a unique and consistant fs number, you won't need
to worry about the instability of device numbers.

NeilBrown