Re: Possible data corruption sata_sil24?

[Tejun Heo <htejun@gmail.com>]

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