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Date: Wed, 12 Feb 2003 14:42:26 -0800
From: Chris Wedgwood <cw@f00f.org>
To: Bruno Diniz de Paula <diniz@cs.rutgers.edu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: O_DIRECT foolish question
Message-ID: <20030212224226.GA13129@f00f.org>
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On Wed, Feb 12, 2003 at 05:29:52PM -0500, Bruno Diniz de Paula wrote:

> But I am using multiples of page size in both buffer alignment and
> buffer size (2nd and 3rd parameters of read).  The issue is that
> when I try to read files with sizes that are NOT multiples of block
> size (and therefore also not multiples of page size), the read
> syscall returns 0, with no errors.

What filesystem?

Can you send an strace of this occurring?

> So the question remains, am I able to read just files whose size is
> a multiple of block size?

No.

You ideally should be able to read any length file with O_DIRECT.
Even a 1-byte file.



  --cw
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