Re: NFS server File Handle changing upon reboot

On Thursday, September 08, 2011 9:45:17 am Rick Macklem wrote:
> Hiroki Sato spotted a problem with NFS server file handles (FHs)
> changing after a server upgrade, because the exported file
> system type(s) get configured in a different order and, therefore,
> assigned different vfs_typenum values.
> 
> A patch has been worked out, after discussion with various folks,
> that uses a hash function to assign the vfs_typenum values.
> 
> This fixes the problem, except it has one downside:
> - The first server boot after the patch has been applied will
>   result in FHs changing and, as such, NFS clients
>   will need to remount after this upgrade.
> 
> So, finally to why I am posting, which is to ask for opinions
> on what should be done with this patch?
> 1 - Ask re_at_ for permission to commit this to -current for 9.0,
>     so that the FH change happens at the 8.X->9.0 upgrade.
>     (It does seem that if some variant of this should go in, then
>      a major release seems like the correct time to do it?)
> 2 - Add a loader.conf variable to the patch, which would allow
>     a sysadmin to "flip the switch" when it is convenient for
>     them. (I do have a concern that this might just cause more
>     confusion w.r.t. when/what needs to be done.)
> 3 - Do #2, for 8.X and make the patch the default for 9.0.
> 4 - Forget the patch and leave things the way the are now.

Well, I would do 3a:  Generate the patch in 2 and merge it to 8, but in 8
have the default be the existing behavior.  In 10 you can remove the switch
altogether.

-- 
John Baldwin