From: Olaf Kirch Subject: NFS directio Date: Thu, 30 Mar 2006 17:15:44 +0200 Message-ID: <20060330151544.GA11915@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.92] helo=mail.sourceforge.net) by sc8-sf-list2.sourceforge.net with esmtp (Exim 4.30) id 1FOytg-0005iP-Km for nfs@lists.sourceforge.net; Thu, 30 Mar 2006 07:17:16 -0800 Received: from mx2.suse.de ([195.135.220.15]) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1FOyte-0002fF-3w for nfs@lists.sourceforge.net; Thu, 30 Mar 2006 07:17:16 -0800 Received: from Relay2.suse.de (mail2.suse.de [195.135.221.8]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id 67B851D0F6 for ; Thu, 30 Mar 2006 17:17:10 +0200 (CEST) Resent-Message-ID: <20060330151710.GB11915@suse.de> To: nfs@lists.sourceforge.net Sender: nfs-admin@lists.sourceforge.net Errors-To: nfs-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: Discussion of NFS under Linux development, interoperability, and testing. List-Post: List-Help: List-Subscribe: , List-Archive: In recent kernels, NFS direct IO limits the size of a request to 4096 pages, ie 16M on most platforms. This causes growisofs from the dvd+rw-tools package (http://fy.chalmers.se/~appro/linux/DVD+RW/) to fail. Its builtin "dd" style function uses 32M buffers by default. It puzzled me a lot that it is returning -EFBIG, which means "file too big". At least that should be EINVAL, I think. EFBIG should be reserved for problems related to largefile support, IMO. We can easily work around the problem by restricting the buffer size growisofs uses on NFS, but that feels strange. I think the right way would be to increase MAX_DIRECTIO_SIZE, and if someone submits a bigger request, to loop and do that in MAX_DIRECTIO_SIZE chunks. Comments? Thanks, Olaf -- Olaf Kirch | --- o --- Nous sommes du soleil we love when we play okir@suse.de | / | \ sol.dhoop.naytheet.ah kin.ir.samse.qurax ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs