add a nfs_server_maxio rc variable to set vfs.nfsd.srvmaxio

[rmacklem]

Summary

vfs.nfsd.srvmaxio can only be set when the nfsd.ko is
loaded, but the nfsd is not running.

For kernels that do not have "options NFSD", putting
the setting in vfs.nfsd.srvmaxio into /etc/sysctl.conf
does not work.

This rc variable sets vfs.nfsd.srvmaxio after nfsd.ko is
loaded, but before the nfsd is started to handle the
case where a kernel does not have "options NFSD".

Test Plan

Tested with a kernel built without "options NFSD",
plus one with "options NFSD".

[0mp]

It would be great to also document this variable in rc.conf.5.

libexec/rc/rc.d/nfsd

33

The other log message in this file starts with a capital letter. I'd try to keep it consistent.

[rmacklem]

Changed the warning message to start with a capital
letter, as suggested by 0mp.

I will do a patch for rc.conf.5 as a separate review.
(Thanks for the reminder!)

[0mp]

Well, the change seems alright. Assuming that the default value for nfs_server_maxio makes sense and that sysctl vfs.nfsd.srvmaxio=${nfs_server_maxio} is useful for nfsd.

libexec/rc/rc.d/nfsd

33

I'd personally paint my bikeshed "I/O" instead of "i/o", but that's probably irrelevant ;)