Re: [fuse-devel] [PATCH v5 7/7] add a flag for per-operation O_DSYNC semantics

From: Anand Avati <avati@gluster.org>
To: Anton Altaparmakov <aia21@cam.ac.uk>
Cc: Jeff Moyer <jmoyer@redhat.com>,
	linux-arch@vger.kernel.org, linux-aio@kvack.org,
	linux-nfs@vger.kernel.org,
	Volker Lendecke <Volker.Lendecke@sernet.de>,
	"Theodore Ts'o" <tytso@mit.edu>,
	linux-mm@kvack.org,
	"fuse-devel@lists.sourceforge.net"
	<fuse-devel@lists.sourceforge.net>,
	linux-api@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Christoph Hellwig <hch@infradead.org>, Tejun Heo <tj@kernel.org>,
	Milosz Tanski <milosz@adfin.com>,
	linux-fsdevel@vger.kernel.org,
	Michael Kerrisk <mtk.manpages@gmail.com>,
	ceph-devel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	ocfs2-devel@oss.oracle.com, Mel Gorman <mgorman@suse.de>
Subject: Re: [fuse-devel] [PATCH v5 7/7] add a flag for per-operation O_DSYNC semantics
Date: Thu, 6 Nov 2014 21:52:07 -0800	[thread overview]
Message-ID: <CAFboF2y2skt=H4crv54shfnXOmz23W-shYWtHWekK8ZUDkfP=A@mail.gmail.com> (raw)
In-Reply-To: <BF30FAEC-D4D3-4079-9ECD-2743747279BD@cam.ac.uk>

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On Thu, Nov 6, 2014 at 8:22 PM, Anton Altaparmakov <aia21@cam.ac.uk> wrote:

> > On 7 Nov 2014, at 01:46, Jeff Moyer <jmoyer@redhat.com> wrote:
> > Minor nit, but I'd rather read something that looks like this:
> >
> >       if (type == READ && (flags & RWF_NONBLOCK))
> >               return -EAGAIN;
> >       else if (type == WRITE && (flags & RWF_DSYNC))
> >               return -EINVAL;
>
> But your version is less logically efficient for the case where "type ==
> READ" is true and "flags & RWF_NONBLOCK" is false because your version then
> has to do the "if (type == WRITE" check before discovering it does not need
> to take that branch either, whilst the original version does not have to do
> such a test at all.
>

Seriously? Just focus on the code readability/maintainability which makes
the code most easily understood/obvious to a new pair of eyes, and leave
such micro-optimizations to the compiler..

Thanks

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