Re: Possible data corruption sata_sil24?

Re: Possible data corruption sata_sil24?

[Tejun Heo]

David Shaw wrote:
>>> It fails whether I use a raw /dev/sdd or partition it into one large
>>> /dev/sdd1, or partition into multiple partitions.  sata_sil24 seems to
>>> work by itself, as does dm, but as soon as I mix sata_sil24+dm, I get
>>> corruption.
>> Hmmmm.... Can you reproduce the corruption by accessing both devices
>> simultaneously without using dm?  Considering ich5 does fine, it looks
>> like hardware and/or driver problem and I really wanna rule out dm.
> 
> I think I wasn't clear enough before.  The corruption happens when I
> use dm to create two dm mappings that both reside on the same real
> device.  Using two different devices, or two different partitions on
> the same physical device works properly.  ich5 does fine with these 3
> tests, but sata_sil24 fails:
> 
>  * /dev/sdd, create 2 dm linear mappings on it, mke2fs and use those
>    dm "devices" == corruption
> 
>  * Partition /dev/sdd into /dev/sdd1 and /dev/sdd2, mke2fs and use
>    those partitions == no corruption
> 
>  * Partition /dev/sdd into /dev/sdd1 and /dev/sdd2, create 2 dm linear
>    mappings on /dev/sdd1, mke2fs and use those dm "devices" ==
>    corruption

I'm not sure whether this is problem of sata_sil24 or dm layer.  Cc'ing
linux-raid for help.  How much memory do you have?  One big difference
between ata_piix and sata_sil24 is that sil24 can handle 64bit DMA.
Maybe dma mapping or something interacts weirdly with dm there?

Thanks.

-- 
tejun

Re: Possible data corruption sata_sil24?

[David Shaw]

On Wed, Jul 18, 2007 at 05:53:39PM +0900, Tejun Heo wrote:
> David Shaw wrote:
> >>> It fails whether I use a raw /dev/sdd or partition it into one large
> >>> /dev/sdd1, or partition into multiple partitions.  sata_sil24 seems to
> >>> work by itself, as does dm, but as soon as I mix sata_sil24+dm, I get
> >>> corruption.
> >> Hmmmm.... Can you reproduce the corruption by accessing both devices
> >> simultaneously without using dm?  Considering ich5 does fine, it looks
> >> like hardware and/or driver problem and I really wanna rule out dm.
> > 
> > I think I wasn't clear enough before.  The corruption happens when I
> > use dm to create two dm mappings that both reside on the same real
> > device.  Using two different devices, or two different partitions on
> > the same physical device works properly.  ich5 does fine with these 3
> > tests, but sata_sil24 fails:
> > 
> >  * /dev/sdd, create 2 dm linear mappings on it, mke2fs and use those
> >    dm "devices" == corruption
> > 
> >  * Partition /dev/sdd into /dev/sdd1 and /dev/sdd2, mke2fs and use
> >    those partitions == no corruption
> > 
> >  * Partition /dev/sdd into /dev/sdd1 and /dev/sdd2, create 2 dm linear
> >    mappings on /dev/sdd1, mke2fs and use those dm "devices" ==
> >    corruption
> 
> I'm not sure whether this is problem of sata_sil24 or dm layer.  Cc'ing
> linux-raid for help.  How much memory do you have?  One big difference
> between ata_piix and sata_sil24 is that sil24 can handle 64bit DMA.
> Maybe dma mapping or something interacts weirdly with dm there?

The machine has 640 megs of RAM.  FWIW, I tried this with 512 megs of
RAM with the same results.  Running Memtest86+ shows the memory is
good.

David

Re: Possible data corruption sata_sil24?

[Tejun Heo]

David Shaw wrote:
>> I'm not sure whether this is problem of sata_sil24 or dm layer.  Cc'ing
>> linux-raid for help.  How much memory do you have?  One big difference
>> between ata_piix and sata_sil24 is that sil24 can handle 64bit DMA.
>> Maybe dma mapping or something interacts weirdly with dm there?
> 
> The machine has 640 megs of RAM.  FWIW, I tried this with 512 megs of
> RAM with the same results.  Running Memtest86+ shows the memory is
> good.

Hmmm... I see, so no DMA to the wrong address problem then.  Let's see
whether dm people can help us out.

Thanks.

-- 
tejun