Re: [ext4] Documentation patch

[Eric Sandeen <sandeen@redhat.com>]

Christoph Hellwig wrote:
> On Mon, Dec 01, 2008 at 05:46:56PM +0100, Harald Arnesen wrote:
>>      So when comparing with a metadata-only journalling filesystem, such
>> -    as ext3, use `mount -o data=writeback'.  And you might as well use
>> +    as jfs or xfs, use `mount -o data=writeback'.  And you might as well use
> 
> data=ordered comes closest to what xfs does for quite a long time..

Agreed; that whole bit which mentions other filesystem comparisons
should probably be stricken, unless it can be
proven/demonstrated/substantiated that ext3 really does "offer higher
data integrity guarantees than most" at this point.

data=ordered ensures that stale data won't be exposed on a crash; xfs
won't do this (it'd be a security bug) and I'd be surprised if jfs or
reiserfs do either.    And it probably *should* be mentioned that
data=writeback bears this risk.

And until ext3 turns on barriers by default, I don't think it's fair to
talk too much about integrity guarantees.  :)

-Eric