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From: Jeff Moyer <jmoyer@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Milosz Tanski <milosz@adfin.com>, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
        Mel Gorman <mgorman@suse.de>,
        Volker Lendecke <Volker.Lendecke@sernet.de>, Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH 7/7] check for O_NONBLOCK in all read_iter instances
References: <cover.1410810247.git.milosz@adfin.com>
	<c31364dee619b2c813c84437561569441fd5fd61.1410810247.git.milosz@adfin.com>
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X-PCLoadLetter: What the f**k does that mean?
Date: Tue, 16 Sep 2014 17:24:29 -0400
In-Reply-To: <20140916210441.GC24591@infradead.org> (Christoph Hellwig's
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Christoph Hellwig <hch@infradead.org> writes:

>> Again, the right return value for the O_DIRECT case is EINVAL.
>
> Is it?  We define -EAGAIN as it would block, which is defintively true
> for O_DIRECT reads.

It will *always* block.  So I don't think it's valid to ask for a
non-blocking read on a file opened with O_DIRECT.  What am I missing?

Cheers,
Jeff