rc scripts change for review

[Doug Barton]

On 04/23/2011 15:40, Rick Macklem wrote:
>>
>>> One thing I am not sure about is the REQUIRE: list in mountd.
>>> nfsserver and nfssrv essentially load the respective module. They
>>> are only
>>> used if sysctl variables need to be set and that's actually done by
>>> nfsd.
>>> (Should they be listed in mountd or nfsd or ???)
>>
>> It's not a good idea to add single scripts that only have a tiny
>> function, especially if they are only called conditionally (I.e., they
>> contain KEYWORD: nostart). It's preferred to handle these things
>> things
>> in the script that needs them, or if it's necessary in more than one
>> script to add a function to the appropriate .subr (rc, or network).
>>
>> So can you say a little more about what you're trying to accomplish?
>> It's not clear to me why instead of doing this:
>>
>> + if ! sysctl vfs.newnfs>/dev/null 2>&1; then
>> + force_depend nfssrv || return 1
>> + fi
>>
>> you would not just do this:
>>
>> + if ! sysctl vfs.newnfs>/dev/null 2>&1; then
>> + load_kld nfsd
>> + fi
>>
> Well, the intent of the above was to get the module loaded so that
> sysctl could manipulate its sysctl variables. I played with it a bit
> and it turns out that neither of the above code snippets work in the
> sense that they don't affect the outcome.
>
> What is needed to make the sysctls work is "nfssrv" has to be in the
> REQUIRED: list for either mountd or nfsd. Without it, the sysctls fail
> with unknown oid. (I'm guessing there is some delay between the load_kld
> and when the module gets its sysctl variables registered?)
>
> Now, I'm not sure whether there is any advantage to specifying "nfssrv"
> in nfsd or mountd, although both seem to work when I test them. "nfsserver"
> is in mountd, so unless you guys have a better suggestion, that's where
> I'll leave it.

 From what you're describing the reason it works by using the nfsserver 
and nfssrv scripts is simply an accident of timing. That's not a good 
thing no matter how you look at it. :)  I understand your dilemma in 
that the nfsserver "solution" was pre-existing, so you were just 
following the example you had. However I have this odd idea that we 
ought to fix broken code, not perpetuate it. Even if I weren't 
interested in this for pedantic value, the fact that it's only working 
now as an accident of timing is a good reason to fix it.

The load_kld module is safe to run unconditionally (it will simply 
return if the module is loaded). So what you could do (for both cases) 
is something like this:

load_kld nfsd
while ! sysctl vfs.newnfs >/dev/null 2>&1; do
	sleep .5
done

If that works, I think we should add that feature to load_kld itself.


Doug

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