Re: 2.6.35-r5 ext3 corruptions

From: Eric Sandeen
Date: Wed Jul 21 2010 - 09:56:16 EST


Dave Chinner wrote:

> Ok, so now I know *why* that one filesystem got busted - I built a
> kernel without CONFIG_EXT3_DEFAULTS_TO_ORDERED set and it got a
> forced reboot (echo b > proc/sysrq-trigger). That'll teach me for
> trying to reproduce bugs Andrew is tripping over with his config
> files.
>
> Quite frankly, data=writeback mode for ext3 is a dangerous,
> dangerous configuration to run by default. IMO, it shouldn't be the
> default. Patch below.

I agree, though I might just remove the config option altogether,
it just obfuscates what's going on, IMHO.

Still, as far as it goes, you can add:

Acked-by: Eric Sandeen <sandeen@xxxxxxxxxx>

to the patch.

-Eric

> ext3: default to ordered mode
>
> From: Dave Chinner <dchinner@xxxxxxxxxx>
>
> data=writeback mode is dangerous and is leads to filesystem
> corruption, data loss and stale data exposure when systems crash. It
> should not be the default, especially when all major distros ensure
> their ext3 filesystems default to ordered mode. Change the default
> mode to the safer data=ordered mode, because we should be caring
> far more about avoiding corruption than performance.
>
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> ---
> fs/ext3/Kconfig | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/fs/ext3/Kconfig b/fs/ext3/Kconfig
> index 522b154..e8c6ba0 100644
> --- a/fs/ext3/Kconfig
> +++ b/fs/ext3/Kconfig
> @@ -31,6 +31,7 @@ config EXT3_FS
> config EXT3_DEFAULTS_TO_ORDERED
> bool "Default to 'data=ordered' in ext3"
> depends on EXT3_FS
> + default y
> help
> The journal mode options for ext3 have different tradeoffs
> between when data is guaranteed to be on disk and

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