Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754036AbYAFCzr (ORCPT ); Sat, 5 Jan 2008 21:55:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752558AbYAFCzj (ORCPT ); Sat, 5 Jan 2008 21:55:39 -0500 Received: from pne-smtpout1-sn1.fre.skanova.net ([81.228.11.98]:33056 "EHLO pne-smtpout1-sn1.fre.skanova.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752248AbYAFCzi (ORCPT ); Sat, 5 Jan 2008 21:55:38 -0500 To: Linus Torvalds Cc: James Bottomley , Matthew Wilcox , Ingo Molnar , linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [patch] scsi: revert "[SCSI] Get rid of scsi_cmnd->done" References: <20080102162534.GA4041@elte.hu> <1199292381.3258.32.camel@localhost.localdomain> <20080102194030.GC11638@parisc-linux.org> <1199304735.3258.53.camel@localhost.localdomain> <1199316785.3258.85.camel@localhost.localdomain> From: Peter Osterlund Date: 06 Jan 2008 03:55:16 +0100 In-Reply-To: Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.4 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2559 Lines: 57 Linus Torvalds writes: > On Wed, 2 Jan 2008, James Bottomley wrote: > > > Look at the taxonomy of the bug. This is the form of the error: > > > > buffer I/O error on device sr0, logical block 20304 > > attempt to access beyond end of device > > sr0: rw=0, want=81224, limit=40944 > > > > The last limit is the most suggestive, that comes straight from > > bdev->bd_inode->i_size>>9 and is supposed to be the size of the block > > device in 512 byte blocks. For a 4.7GB DVD, it's a little small. > > Nothing in the sr code sets this directly (although it does come from > > get_blkdev() for the first opener). pktcdvd does set it, though ... and > > probably wrongly if the drive in question isn't UDF formatted. pktcdvd sets it when opening the /dev/pktcdvd device, but when the drive is later opened as /dev/scd0, there is nothing that sets it back. (Btw, 40944 is possible if the disk is a CDRW that was formatted with "cdrwtool -m 10236".) The problem is that pktcdvd opens the cd device in non-blocking mode when pktsetup is run, and doesn't close it again until pktsetup -d is run. The effect is that if you meanwhile open the cd device, blkdev.c:do_open() doesn't call bd_set_size() because bdev->bd_openers is non-zero. I don't know the correct way to fix this. Maybe adding bd_set_size() to sr.c:get_sectorsize() which already does set_capacity() would work. > .. but you're ignoring the fact that if pktcdvd sets it wrong, then it > should be visible with the pre-commit kernel *also*. I can repeat this bug, both with and without the scsi patch that is claimed to make a difference, both with an external USB drive and an internal IDE drive. To repeat: 1. Start with an empty drive. 2. pktsetup 0 /dev/scd0 3. Insert a CD containing an isofs filesystem. 4. mount /dev/pktcdvd/0 /mnt/tmp 5. umount /mnt/tmp 6. Press the eject button. 7. Insert a DVD containing a non-writable filesystem. 8. mount /dev/scd0 /mnt/tmp 9. find /mnt/tmp -type f -print0 | xargs -0 sha1sum >/dev/null 10. If the DVD contains data beyond the physical size of a CD, you get I/O errors in the terminal, and dmesg reports lots of "attempt to access beyond end of device" errors. -- Peter Osterlund - petero2@telia.com http://web.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/