Re: [RFC] mount flag "direct"

Lars Marowsky-Bree
2002-09-03T16:17:44Z

On 2002-09-03T17:44:10,
"Peter T. Breuer" <ptb@it.uc3m.es> said:

> No! I do not want /A/ fs, but /any/ fs, and I want to add the vfs
> support necessary :-).
>
> That's really what my question is driving at. I see that I need to
> make VFS ops communicate "tag requests" to the block layer, in
> order to implement locking. Now you and Rik have pointed out one
> operation that needs locking. My next question is obviously: can you
> point me more or less precisely at this operation in the VFS layer?
> I've only started studying it and I am relatively unfamiliar with it.

Your approach is not feasible.

Distributed filesystems have a lot of subtle pitfalls - locking, cache
coherency, journal replay to name a few - which you can hardly solve at the
VFS layer.

Good reading would be any sort of entry literature on clustering, I would
recommend "In search of clusters" and many of the whitepapers Google will turn
up for you, as well as the OpenGFS source.

Sincerely,
Lars Marowsky-Brée <lmb@suse.de>

--
Immortality is an adequate definition of high availability for me.
--- Gregory F. Pfister