RFC: new NFS mount option to work around Solaris server bug

[Konstantin Belousov]

On Wed, Dec 24, 2014 at 06:14:58PM -0500, Rick Macklem wrote:
> Hi,
> 
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=193128
> 
> This bug report discusses a bug in the Solaris NFS server
> that is tickled by the way FreeBSD currently does exclusive
> open in the NFS client.
> FreeBSD sets both the mtime to the time of the client and
> also the file's mode using a Setattr RPC done after an
> exclusive create of the file in an exclusive open.
> 
> Jason (jnaughto at ee.ryerson.ca) was able to figure out that
> the server bug can be avoided if the mtime is set to the
> server's time (xxx_TOSERVER option in the Setattr RPC request).
> 
> I'd like to propose a new mount option that forces the
> FreeBSD client to use xxx_TOSERVER for setting times,
> mostly to be used as a work around for this Solaris server bug.
> 1 - Does doing this make sense to others?
> 2 - If the answer to one is "Yes", then what do you think
>     the option should be called?
>     useservertime
>     useservtm
>     ust
>     OR ??

What are drawbacks of unconditionally using the workaround ?