From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Dilger Subject: Why is O_DIRECT checking deferred? Date: Sat, 22 Jun 2002 12:50:35 -0600 Sender: linux-fsdevel-owner@vger.kernel.org Message-ID: <20020622185035.GE22411@clusterfs.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: viro@math.psu.edu, linux-fsdevel@vger.kernel.org Return-path: To: andrea@suse.de Content-Disposition: inline List-Id: linux-fsdevel.vger.kernel.org Andrea, Al, I'm implementing O_DIRECT for our network filesystem, Lustre. One strange thing I noticed is that we do not check for a_ops->direct_IO until deep in the read/write path instead of failing at open time. Since not many filesystem implement O_DIRECT I was going to submit a patch to generic_direct_IO() which printk's an error if a_ops->direct_IO is not available, but it would really be better to do this at open time before allocating the kiobuf. Cheers, Andreas -- Andreas Dilger http://www-mddsp.enel.ucalgary.ca/People/adilger/ http://sourceforge.net/projects/ext2resize/