From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261370AbVFFMor (ORCPT ); Mon, 6 Jun 2005 08:44:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261383AbVFFMor (ORCPT ); Mon, 6 Jun 2005 08:44:47 -0400 Received: from smtp2.rz.tu-harburg.de ([134.28.205.13]:3870 "EHLO smtp2.rz.tu-harburg.de") by vger.kernel.org with ESMTP id S261370AbVFFMo3 (ORCPT ); Mon, 6 Jun 2005 08:44:29 -0400 Message-ID: <42A44515.4020701@tu-harburg.de> Date: Mon, 06 Jun 2005 14:44:05 +0200 From: Jan Blunck User-Agent: Debian Thunderbird 1.0.2 (X11/20050331) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Christoph Hellwig CC: Andrew Morton , Linux-Kernel Mailing List Subject: Re: [PATCH] don't allow sys_readahead() on files opened with O_DIRECT References: <42A435DE.50302@tu-harburg.de> <20050606114324.GA7774@infradead.org> In-Reply-To: <20050606114324.GA7774@infradead.org> X-Enigmail-Version: 0.91.0.0 Content-Type: multipart/mixed; boundary="------------080108030505060106000608" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------080108030505060106000608 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Christoph Hellwig wrote: > your check is wrong, it's testing whether the filesystem supports O_DIRECT, not > whether sys_readahead is used on a file descriptor that has been opened with O_DIRECT D'oh! You're right. Jan --------------080108030505060106000608 Content-Type: text/x-patch; name="filemap.c_direct_IO_readahead.diff" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="filemap.c_direct_IO_readahead.diff" do_readahead() doesn't make sense if the file is opened with O_DIRECT, since only the page cache is stuffed but never used. Signed-off-by: Jan Blunck mm/filemap.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletion(-) Index: experimental-um/mm/filemap.c =================================================================== --- experimental-um.orig/mm/filemap.c +++ experimental-um/mm/filemap.c @@ -1110,7 +1110,8 @@ static ssize_t do_readahead(struct address_space *mapping, struct file *filp, unsigned long index, unsigned long nr) { - if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage) + if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage + || (filp->f_flags & O_DIRECT)) return -EINVAL; force_page_cache_readahead(mapping, filp, index, --------------080108030505060106000608--