Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265507AbUABKvp (ORCPT ); Fri, 2 Jan 2004 05:51:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265510AbUABKvp (ORCPT ); Fri, 2 Jan 2004 05:51:45 -0500 Received: from smtp5.hy.skanova.net ([195.67.199.134]:33007 "EHLO smtp5.hy.skanova.net") by vger.kernel.org with ESMTP id S265507AbUABKvn (ORCPT ); Fri, 2 Jan 2004 05:51:43 -0500 To: arjanv@redhat.com Cc: Andrew Morton , axboe@suse.de, packet-writing@suse.com, linux-kernel@vger.kernel.org Subject: Re: ext2 on a CD-RW References: <20040101162427.4c6c020b.akpm@osdl.org> <1073034412.4429.1.camel@laptop.fenrus.com> From: Peter Osterlund Date: 02 Jan 2004 11:51:24 +0100 In-Reply-To: <1073034412.4429.1.camel@laptop.fenrus.com> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1482 Lines: 29 Arjan van de Ven writes: > On Fri, 2004-01-02 at 02:30, Peter Osterlund wrote: > > > The packet writing code has the restriction that a bio must not span a > > packet boundary. (A packet is 32*2048 bytes.) If the page when mapped > > to disk starts 2kb before a packet boundary, merge_bvec_fn therefore > > returns 2048, which is less than len, which is 4096 if the whole page > > is mapped, so the bio_add_page() call fails. > > devicemapper has similar restrictions for raid0 format; in that case > it's device-mappers job to split the page/bio. Just as it is UDF's task > to do the same I suspect... Old versions of the packet writing code did just that, but Jens told me that bio splitting was evil, so when the merge_bvec_fn functionality was added to the kernel, I started to use it. http://lists.suse.com/archive/packet-writing/2002-Aug/0044.html If merge_bvec_fn is not supposed to be able to handle the need of the packet writing code, I can certainly resurrect my bio splitting code. Btw, for some reason, this bug is not triggered when using the UDF filesystem on a CDRW. I've only seen it with the ext2 filesystem. -- Peter Osterlund - petero2@telia.com http://w1.894.telia.com/~u89404340 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/