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Message-Id: <200610060311.k963BZEt015374@shell0.pdx.osdl.net>
Date: Thu, 05 Oct 2006 20:11:35 -0700
From: akpm@...l.org
To: mm-commits@...r.kernel.org
Cc: dim@...nvz.org, dev@...nvz.org, linux-ext4@...r.kernel.org,
vvs@...ru
Subject: + ext4-errors-behaviour-fix.patch added to -mm tree
The patch titled
ext4: errors behaviour fix
has been added to the -mm tree. Its filename is
ext4-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: ext4: errors behaviour fix
From: Dmitry Mishin <dim@...nvz.org>
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:
EXT4_ERRORS_CONTINUE should be taken from the superblock as default value for
error behaviour.
Signed-off-by: Dmitry Mishin <dim@...nvz.org>
Acked-by: Vasily Averin <vvs@...ru>
Acked-by: Kirill Korotaev <dev@...nvz.org>
Cc: <linux-ext4@...r.kernel.org>
Signed-off-by: Andrew Morton <akpm@...l.org>
---
fs/ext4/super.c | 2 ++
1 file changed, 2 insertions(+)
diff -puN fs/ext4/super.c~ext4-errors-behaviour-fix fs/ext4/super.c
--- a/fs/ext4/super.c~ext4-errors-behaviour-fix
+++ a/fs/ext4/super.c
@@ -1526,6 +1526,8 @@ static int ext4_fill_super (struct super
set_opt(sbi->s_mount_opt, ERRORS_PANIC);
else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_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);
_
Patches currently in -mm which might be from dim@...nvz.org are
ext4-errors-behaviour-fix.patch
ext3-errors-behaviour-fix.patch
-
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