From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH] hostfs: Use noop_fsync for directories
Date: Wed, 14 Jan 2015 00:39:51 -0800
Message-ID: <20150114083951.GA29714@infradead.org>
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 <20150113221958.GA27739@infradead.org>
 <54B59B9E.4000806@nod.at>
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Cc: Christoph Hellwig <hch@infradead.org>,
	user-mode-linux-devel@lists.sourceforge.net, dxld@darkboxed.org,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
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To: Richard Weinberger <richard@nod.at>
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On Tue, Jan 13, 2015 at 11:26:38PM +0100, Richard Weinberger wrote:
> hostfs tries do reduce the amount of syscall between guest and host as much
> as possible. For file operations it passes everything down to the host but
> for directory operations only ->iterate() does.
> 
> It is already horrible slow, if we add an ->open() for directory too it would
> get even more slower. :-(

This sounds fairlt dangerous.  At least add some good documentation
explaining these semantics.