From: akpm@osdl.org Subject: + ext3-errors-behaviour-fix.patch added to -mm tree Date: Thu, 05 Oct 2006 15:48:09 -0700 Message-ID: <200610052248.k95MmAfX007528@shell0.pdx.osdl.net> Cc: dim@openvz.org, dev@openvz.org, linux-ext4@vger.kernel.org, vvs@sw.ru Return-path: Received: from smtp.osdl.org ([65.172.181.4]:29374 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751401AbWJEWs2 (ORCPT ); Thu, 5 Oct 2006 18:48:28 -0400 To: mm-commits@vger.kernel.org Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org The patch titled ext3: errors behaviour fix has been added to the -mm tree. Its filename is ext3-errors-behaviour-fix.patch See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this ------------------------------------------------------ Subject: ext3: errors behaviour fix From: Dmitry Mishin Current error behaviour for ext2 and ext3 filesystems does not fully correspond to the documentation and should be fixed. According to man 8 mount, ext2 and ext3 file systems allow to set one of 3 different on-errors behaviours: ---- start of quote man 8 mount ---- errors=continue / errors=remount-ro / errors=panic Define the behaviour when an error is encountered. (Either ignore errors and just mark the file system erroneous and continue, or remount the file system read-only, or panic and halt the system.) The default is set in the filesystem superblock, and can be changed using tune2fs(8). ---- end of quote ---- However EXT3_ERRORS_CONTINUE is not read from the superblock, and thus ERRORS_CONT is not saved on the sbi->s_mount_opt. It leads to the incorrect handle of errors on ext3. Then we've checked corresponding code in ext2 and discovered that it is buggy as well: - EXT2_ERRORS_CONTINUE is not read from the superblock (the same); - parse_option() does not clean the alternative values and thus something like (ERRORS_CONT|ERRORS_RO) can be set; - if options are omitted, parse_option() does not set any of these options. Therefore it is possible to set any combination of these options on the ext2: - none of them may be set: EXT2_ERRORS_CONTINUE on superblock / empty mount options; - any of them may be set using mount options; - 2 any options may be set: by using EXT2_ERRORS_RO/EXT2_ERRORS_PANIC on the superblock and other value in mount options; - and finally all three options may be set by adding third option in remount. Currently ext2 uses these values only in ext2_error() and it is not leading to any noticeable troubles. However somebody may be discouraged when he will try to workaround EXT2_ERRORS_PANIC on the superblock by using errors=continue in mount options. This patch: EXT3_ERRORS_CONTINUE should be taken from the superblock as default value for error behaviour. Signed-off-by: Dmitry Mishin Acked-by: Vasily Averin Acked-by: Kirill Korotaev Cc: Signed-off-by: Andrew Morton --- fs/ext3/super.c | 2 ++ 1 files changed, 2 insertions(+) diff -puN fs/ext3/super.c~ext3-errors-behaviour-fix fs/ext3/super.c --- a/fs/ext3/super.c~ext3-errors-behaviour-fix +++ a/fs/ext3/super.c @@ -1470,6 +1470,8 @@ static int ext3_fill_super (struct super set_opt(sbi->s_mount_opt, ERRORS_PANIC); else if (le16_to_cpu(sbi->s_es->s_errors) == EXT3_ERRORS_RO) set_opt(sbi->s_mount_opt, ERRORS_RO); + else + set_opt(sbi->s_mount_opt, ERRORS_CONT); sbi->s_resuid = le16_to_cpu(es->s_def_resuid); sbi->s_resgid = le16_to_cpu(es->s_def_resgid); diff -puN /dev/null /dev/null _ Patches currently in -mm which might be from dim@openvz.org are ext3-errors-behaviour-fix.patch