Re: reiser4 plugins

Nikita Danilov
2005-06-22T22:32:56Z

David Masover writes:

[...]

>
> What we want is to have programs that can write small changes to one
> file or to many files, lump all those changes into a transaction, and
> have the transaction either succeed or fail.

No existing file system guarantees such behavior. Even atomicity of
single system call is not guaranteed.

>
> > it doesn't stop the system dead in its tracks waiting for some very long
> > transaction to finish?
>
> We've also discussed this. For one thing, if we can have transactions
> in databases which don't stop the database dead in its tracks, why can't
> we do it with filesystems?

Because to have such transactions databases pay huge price in both
resource consumption and available concurrency (isolation, commit-time
locks, etc.), and yet mechanism they use to deal with stuck transactions
(which is simply to abort it) is not very suitable for the file system.

>
> But anyway, if you really want to know, ask someone else or read the
> archives. I wasn't really paying attention except to remember that this
> issue was resolved.

That would be real breakthrough.

[...]

>
> >> fibretions, etc,
> >
> >
> > ???
>
> Low-level tweaking. I think the word is from some sort of calculus.

Fibration. http://marc.theaimsgroup.com/?l=linux-kernel&m=108032604606183&w=2

Nikita.