Re: [RFC] mount flag "direct"

Daniel Phillips
2002-09-03T18:24:09Z

On Tuesday 03 September 2002 18:41, Peter T. Breuer wrote:
> > Distributed filesystems have a lot of subtle pitfalls - locking, cache
>
> Yes, thanks, I know.
>
> > coherency, journal replay to name a few - which you can hardly solve at
> > the
>
> My simple suggestion is not to cache. I am of the opinion that in
> principle that solves all coherency problems, since there would be no
> stored state that needs to "cohere". The question is how to identify
> and remove the state that is currently cached.

Well, for example, you would not be able to have the same file open in two
different kernels because the inode would be cached. So you'd have to close
the root directory on one kernel before the other could access any file. Not
only would that be horribly inefficient, you would *still* need to implement
a locking protocol between the two kernels to make it work.

There's no magic way of making this easy.

--
Daniel