Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261826AbVD0RTx (ORCPT ); Wed, 27 Apr 2005 13:19:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261810AbVD0RTN (ORCPT ); Wed, 27 Apr 2005 13:19:13 -0400 Received: from mail.kroah.org ([69.55.234.183]:28358 "EHLO perch.kroah.org") by vger.kernel.org with ESMTP id S261824AbVD0RRp (ORCPT ); Wed, 27 Apr 2005 13:17:45 -0400 Date: Wed, 27 Apr 2005 10:16:27 -0700 From: Greg KH To: erik@debian.franken.de, Andries.Brouwer@cwi.nl Cc: linux-kernel@vger.kernel.org, stable@kernel.org, Justin Forbes , Zwane Mwaikambo , Cliff White , "Theodore Ts'o" , "Randy.Dunlap" , Chuck Wolber , torvalds@osdl.org, akpm@osdl.org, alan@lxorguk.ukuu.org.uk Subject: [04/07] partitions/msdos.c fix Message-ID: <20050427171627.GE3195@kroah.com> References: <20050427171446.GA3195@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050427171446.GA3195@kroah.com> User-Agent: Mutt/1.5.8i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2804 Lines: 71 -stable review patch. If anyone has any objections, please let us know. ------------------ Erik reports this fixes an oops on boot for him. From: Andries Brouwer A well-known kernel bug is that it guesses at the partition type and the partitions on any disk it encounters. This is bad because needless I/O is done, slowing down the boot, sometimes quite a lot, especially when I/O errors occur. And it is bad because sometimes we guess wrong. In other words, we need the user space command `partition', where "partition -t dos /dev/sda" reads a DOS-type partition table. (And "partition /dev/sda" tries all known heuristics to decide what type of partitioning might be present.) The two variants are: (i) partition tells the kernel to do the partition table reading, and (ii) partition uses partx to read the partition table and tells the kernel one-by-one about the partitions found this way. Since this is a fundamental change, a long transition period is needed, and that period could start with a kernel boot parameter telling the kernel not to do partition table parsing on a particular disk, or a particular type of disks, or all disks. This could have been the intro to a patch doing that, but is not. (It is just an RFC.) The tiny patch below prompted the above - it was suggested by Uwe Bonnes who encountered USB devices without partition table where our present heuristics did not suffice to stop partition table parsing. It causes the kernel to ignore partitions of type 0. A band-aid. I think nobody uses such partitions seriously, but nevertheless this should probably live in -mm for a while to see if anybody complains. Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman --- ===== fs/partitions/msdos.c 1.26 vs 1.27 ===== --- 1.26/fs/partitions/msdos.c 2004-11-09 12:43:17 -08:00 +++ 1.27/fs/partitions/msdos.c 2005-03-07 20:41:42 -08:00 @@ -114,6 +114,9 @@ parse_extended(struct parsed_partitions */ for (i=0; i<4; i++, p++) { u32 offs, size, next; + + if (SYS_IND(p) == 0) + continue; if (!NR_SECTS(p) || is_extended_partition(p)) continue; @@ -430,6 +433,8 @@ int msdos_partition(struct parsed_partit for (slot = 1 ; slot <= 4 ; slot++, p++) { u32 start = START_SECT(p)*sector_size; u32 size = NR_SECTS(p)*sector_size; + if (SYS_IND(p) == 0) + continue; if (!size) continue; if (is_extended_partition(p)) { - 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/