From: Eric Sandeen Subject: [PATCH] e2fsprogs: fix blkid whole-disk scanning heuristics Date: Thu, 29 Nov 2007 12:57:35 -0600 Message-ID: <474F0B9F.5070902@sandeen.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Theodore Tso To: ext4 development Return-path: Received: from sandeen.net ([209.173.210.139]:19758 "EHLO sandeen.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762883AbXK2TbP (ORCPT ); Thu, 29 Nov 2007 14:31:15 -0500 Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org The heuristics in blkid/devname.c probe_all() for scanning whole disks with no partitions assume that a device name with no digit on the end will always be present as a delineator, i.e.: sda sda1 sdb sdc In this case, when sdc is seen, it's the clue to go back and scan sdb. however, for something like: sda sda1 sdb loop0 this falls down, and sdb is never scanned. (thanks to Karel Zak for pointing this out). I believe the following patch will fix this up, but when messing with partition scanning, I don't mind a second opinion. :) Thanks, -Eric --- Addresses-Red-Hat-Bugzilla: #400321 Signed-off-by: Eric Sandeen Index: e2fsprogs-1.40.2/lib/blkid/devname.c =================================================================== --- e2fsprogs-1.40.2.orig/lib/blkid/devname.c +++ e2fsprogs-1.40.2/lib/blkid/devname.c @@ -490,10 +490,11 @@ static int probe_all(blkid_cache cache, DBG(DEBUG_DEVNAME, printf("read partition name %s\n", ptname)); - /* Skip whole disk devs unless they have no partitions - * If we don't have a partition on this dev, also + /* Skip whole disk devs unless they have no partitions. + * If base name of device has changed, also * check previous dev to see if it didn't have a partn. - * heuristic: partition name ends in a digit. + * heuristic: partition name ends in a digit, & partition + * names contain whole device name as substring. * * Skip extended partitions. * heuristic: size is 1 @@ -502,6 +503,8 @@ static int probe_all(blkid_cache cache, */ lens[which] = strlen(ptname); + + /* ends in a digit, clearly a partition, so check */ if (isdigit(ptname[lens[which] - 1])) { DBG(DEBUG_DEVNAME, printf("partition dev %s, devno 0x%04X\n", @@ -510,10 +513,15 @@ static int probe_all(blkid_cache cache, if (sz > 1) probe_one(cache, ptname, devs[which], 0, only_if_new); - lens[which] = 0; - lens[last] = 0; - } else if (lens[last] && strncmp(ptnames[last], ptname, - lens[last])) { + lens[which] = 0; /* mark as checked */ + } + + /* + * If last was not checked because it looked like a whole-disk + * dev, and the device's base name has changed, + * check last as well. + */ + if (lens[last] && strncmp(ptnames[last], ptname, lens[last])) { DBG(DEBUG_DEVNAME, printf("whole dev %s, devno 0x%04X\n", ptnames[last], (unsigned int) devs[last]));