I can't be sure if the patch is correct, but I definitely agree that
write gathering should be turned off for V3. For my current server,
the write gathering code is ripped out completely.

write gathering made some sense (it depended upon your configuration)
when clients were mostly V2 with lots of biods running, but that was
10 years ago. It makes no sense for V3 clients that use async writes and
a commit later and the same goes for old V2 clients (such as DOS clients)
that don't have nfsiods/biods that do bursts of write RPCs.

At this point, I'd go a step further and just strip out all the write
gathering stuff.

Just mho, rick