Re: ext4: Fix data corruption with multi-block writepages support

[Matt <jackdachef@gmail.com>]

On Mon, Feb 7, 2011 at 5:45 PM, Ted Ts'o <tytso@mit.edu> wrote:
> On Fri, Feb 04, 2011 at 10:40:47PM +0000, Matt wrote:
>>
>> So that means that the file-corruption which existed until 2.6.37-rc6
>> and got triggered (for me) more easily via "dm crypt: scale to
>> multiple CPUs"
>> is fixed now ?
>
> Well, a patch exists for it that will be merged into 2.6.38.
>
>> That should give ext4 a nice speedup for >=2.6.38 :)
>
> I'm not going to make it be the default for 2.6.38, since it's fairly
> late in the -rc features.  People who want it can explicitly enable it
> using the mount option mblk_io_submit, though.  (And let me know your
> success stories!  :-) I will be enabling it as the default in
> 2.6.39-rc1.
>

Hi Ted,

I guess it should be save to enable it with 2.6.37, dm-crypt multi-cpu
patch and the following patch ?

"ext4: Fix data corruption with multi-block writepages support"
(of course that's the minimum - it would be better to pull in the ext4
changes for 2.6.38)


For a short time I had it activated (via additional) mblk_io_submit
mount-command on my portage-partition (where the portage-ball of my
Gentoo system is).
I was curious to see what messages I would get and wondered why there
was nothing about mballoc mentioned

If I recall correctly there were always messages in the past, like:

EXT4-fs: delayed allocation enabled
EXT4-fs: file extents enabled
EXT4-fs: mballoc enabled

these are from 2.6.28 -

I'm only getting:

EXT4-fs (dm-3): mounted filesystem with ordered data mode.

or

EXT4-fs (dm-3): mounted filesystem with ordered data mode. Opts:
commit=60,barrier=1

(I like to set the barriers / flushes explicitly).

Sorry if I didn't follow development but these messages were kind of
more and more silenced ?


Thanks !


>> Reported-by: Matthias Bayer <jackdachef <at> gmail <dot> com >
>
> Sure!

Thanks !


>
>                                                - Ted
>

Regards

Matt