Date: Fri, 13 May 2005 14:24:51 +0200
From: =?iso-8859-1?Q?J=F6rn?= Engel <joern@wohnheim.fh-wedel.de>
To: Kyle Moffett <mrmacman_g4@mac.com>
Cc: Markus Klotzbuecher <mk@creamnet.de>, linux-kernel@vger.kernel.org
Subject: Re: [ANNOUNCE] mini_fo-0.6.0 overlay file system
Message-ID: <20050513122451.GD9255@wohnheim.fh-wedel.de>
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On Fri, 13 May 2005 07:26:14 -0400, Kyle Moffett wrote:
> 
> >It solves the biggest concern I had left for union mount.  Actually
> >implementing it, though, depends on quite a bit of infrastructure  
> >that just
> >doesn't exist yet.  Still, a very interesting idea.
> 
> For ext2/ext3, the sparse-file-support _does_ exist, so the only  
> major parts
> that need to be added are:
>     o An extra ext2/ext3 flag that indicates nonresidence (For both  
> sparse
>       files, normal files, and directories).
>     o VFS-level support for the union operation with hooks to let each
>       filesystem do something special.

That and replacing the page cache by something different.  Page cache
is referencing pages by inode,offset pairs.  Having a potentially
infinite amount of inodes to look at, in order, may require a tiny bit
of patching. ;)

J?rn

-- 
Linux [...] existed just for discussion between people who wanted
to show off how geeky they were.
-- Rob Enderle
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