From joern at logfs.org  Mon Nov 10 16:14:52 2008
From: joern at logfs.org (=?utf-8?B?SsO2cm4=?= Engel)
Date: Mon, 10 Nov 2008 16:14:52 +0100
Subject: [PATCH] LogFS as root filesystem
In-Reply-To: <20081110065648.GA8761@shurick.s2s.msu.ru>
References: <20081110065648.GA8761@shurick.s2s.msu.ru>
Message-ID: <20081110151452.GA16520@logfs.org>

On Mon, 10 November 2008 09:56:48 +0300, Alexander Inyukhin wrote:
> 
> I tried to investigate issue with using LogFS as root fs.
> Patch and "proof pic" are attached.

Excellent!

> The patch is very simple. It changes three things:
> 1) Set FS_REQUIRES_DEV flag. It used by kernel to
>    distinguish between "real" and "fake" (like proc)
>    filesystems. Only former filesystems are probed
>    while kernel tries to mount root. (There is
>    rootfstype kernel option to do this manually.)
> 2) LogFS ignores ro mount option and always opens
>    device in rw mode. Probably, this is not
>    related to the issue, but I think, it should
>    be fixed too.
> 3) LogFS do not set up special inodes correctly,
>    and devices like initial console are inaccessible
>    during boot. (Probably, initramfs with udev
>    could fix this too.)

I'll take the lot.  The last one I've actually rewritten a bit to
prevent similar problems in the future.  Default action is BUG() now, so
that any unknown mode will trigger an explicit complaint instead of
silently doing something unexpected.

> root at Knoppix:/# cat /proc/mounts 
> rootfs / rootfs rw 0 0
> /dev/root / logfs rw 0 0

:)

J?rn

-- 
The only real mistake is the one from which we learn nothing.
-- John Powell