Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 2 Nov 2002 14:13:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 2 Nov 2002 14:13:42 -0500 Received: from hera.cwi.nl ([192.16.191.8]:51640 "EHLO hera.cwi.nl") by vger.kernel.org with ESMTP id ; Sat, 2 Nov 2002 14:13:41 -0500 From: Andries.Brouwer@cwi.nl Date: Sat, 2 Nov 2002 20:19:22 +0100 (MET) Message-Id: To: marcelo@connectiva.com.br, pasky@pasky.ji.cz Subject: Re: [PATCH] [2.4.19] Extended /proc/partitions Cc: Andries.Brouwer@cwi.nl, hch@lst.de, linux-kernel@vger.kernel.org, torvalds@transmeta.com, viro@math.psu.edu Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1943 Lines: 45 From pasky@machine.sinus.cz Sat Nov 2 18:18:06 2002 From: Petr Baudis This patch extends contents of /proc/partitions by starting offset of each partition. This can be terribly useful if you by some mistake over-dd'd the partition table on a disk, but the system is still up. I know that you can also dig this out by some ioctl()s, but this can make life a lot easier for those who don't know C or can't dig the ioctl codes from the kernel source code. (0) When it is too late, many people realize that they could have made a backup, either with dd to some file, or with # sfdisk -d /dev/hda both to file and printer. (1) These ioctls are used by existing programs. So, for example, # hdparm -g /dev/hda5 will give you the starting offset (in 512-byte sectors) of /dev/hda5. Even better may be a command like # blockdev --report (2) Several programs, like mount, *fdisk, blockdev, read /proc/partitions. Changing the format will break all of these. So, it is best not to change anything, but if you do, only add fields at the end. (2a) Maybe /proc/partitions is already extended with disk statistics. Certainly some vendors do so, and it is rumoured that stock 2.4.20 will (optionally) do so. Given this uncertainty about what comes after the currently present fields, it is now impossible to add anything new, unless all programs using /proc/partitions also parse the header line. It is best to consider /proc/partitions frozen. Linux 2.5 has driverfs, and although "cat /proc/partitions" is much more convenient than searching around in driverfs (sysfs), no doubt blockdev will be changed so as to report on sysfs, when that exists and is mounted. Andries - 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/