Re: [PATCH] [Request for inclusion] Filesystem in Userspace

Jan Hudec
2004-11-26T22:01:46Z

[-- Attachment #1: Type: text/plain, Size: 1492 bytes --]

On Wed, Nov 24, 2004 at 14:05:51 +0100, Miklos Szeredi wrote:
> > http://lkml.org/lkml/2004/7/26/68
> >
> > discusses a userspace filesystem (implemented as a userspace nfs server
> > mounted on a loopback nfs mount), the problem, a solution (exactly your
> > suggestion), and a more generic solution.
>
> Thanks for the pointer, very interesting read.
>
> However, I don't like the idea that the userspace filesystem must
> cooperate with the kernel in this regard. With this you lose one of
> the advantages of doing filesystem in userspace: namely that you can
> be sure, that anything you do cannot bring the system down.
>
> And I firmly believe that this can be done without having to special
> case filesystem serving processes.
>
> There are already "strange" filesystems in the kernel which cannot
> really get rid of dirty data. I'm thinking of tmpfs and ramfs.
> Neither of them are prone to deadlock, though both of them are "worse
> off" than a userspace filesystem, in the sense that they have not even
> the remotest chance of getting rid of the dirty data.
>
> Of course, implementing this is probably not trivial. But I don't see
> it as a theoretical problem as Linus does.
>
> Is there something which I'm missing here?

But they KNOW that they won't be able to get rid of the dirty data. But
fuse does not.

-------------------------------------------------------------------------------
Jan 'Bulb' Hudec <bulb@ucw.cz>

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 189 bytes --]