Re: Vnode scope implementation

[Elad Efrat <elad%NetBSD.org@localhost>]

On Tue, Aug 25, 2009 at 4:00 PM, YAMAMOTO 
Takashi<yamt%mwd.biglobe.ne.jp@localhost> wrote:
> hi,
>
>> On Tue, Aug 25, 2009 at 11:43 AM, YAMAMOTO
>> Takashi<yamt%mwd.biglobe.ne.jp@localhost> wrote:
>>
>>>>> does it mean the use of the vnode scope is optional and a filesystem is
>>>>> free to choose not using it, right?
>>>>
>>>> No, what is your reasoning here?
>>>
>>> what do you mean by "No"?  it won't be optional?
>>> it can't be mandated because it's simply impossible for some filesystems.
>>
>> Just because it's impossible for *some* file-systems doesn't mean we
>> shouldn't be doing it for *all* file-systems. If NFS has limitations,
>> why should they affect file-systems that do not?
>>
>> I would rather have a note that says "security policies can't
>> explicitly allow operations on NFS mounts, as the server gets the
>> final word", than one that says "the vnode scope is not implemented
>> for ufs, ext2fs, tmpfs, etc. because NFS has certain limitations it
>> forces on what security policies can do."
>
> i guess that you misunderstand what i said.
> i'm merely saying that filesystems should be allowed to choose not
> using the vnode scope.  what's wrong with it?

My mistake: nothing is wrong with it; I misunderstood. For now I'll
just do support for the file-systems that can use it.

>>> sometimes you can't short-circuit with the suggested api because you
>>> need to get "fs_decision" first.
>>
>> We can pass -1 for fs_decision in the NFS case, or altogether leave
>> NFS out of the plans for now. I don't think it has that much weight at
>> this point.
>
> what does -1 mean?

It can mean "the file-system does not support decision-before-action".
(that's the best I can come up with now :)

Thanks,

-e.