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Date: Fri, 15 Jan 2016 01:29:49 -0800
From: Christoph Hellwig <hch@infradead.org>
To: Christoph Hellwig <hch@infradead.org>,
	Nikhilesh Reddy <reddyn@codeaurora.org>,
	Miklos Szeredi <miklos@szeredi.hu>,
	fuse-devel <fuse-devel@lists.sourceforge.net>,
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	linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
	Richard Weinberger <richard.weinberger@gmail.com>,
	Theodore Ts'o <tytso@mit.edu>, jack@suse.cz,
	Antonio SJ Musumeci <trapexit@spawn.link>, sven.utcke@gmx.de
Subject: Re: [PATCH] fuse: Add support for fuse stacked I/O
Message-ID: <20160115092949.GA11468@infradead.org>
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 <20160114082554.GA12489@infradead.org>
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On Thu, Jan 14, 2016 at 07:52:00AM -0800, Nikolaus Rath wrote:
> > Please write your stacked features as kernel drivers.
> 
> Could you explain in more detail? I think I don't understand either the
> why, the how, or what you mean with driver in this context (not sure
> which one it is). 
> 
> 
> (I'm not the original submitter but interested in this)


If someone is doing stacked pass through I/O, which basically is some
form of unioning or file hiding it should be using overlayfs or a new
kernel stackable file system.  That's not to say it could be prototyped
entirely in userspace, but it's not something we should add any bypasses
for.