Re: [PATCH] extend e2fsprogs functionality to add EXT2_FLAG_DIRECT option

Michal Novotny
2010-01-12T16:51:48Z

On 01/12/2010 05:47 PM, Christoph Hellwig wrote:
> On Tue, Jan 12, 2010 at 05:43:21PM +0100, Michal Novotny wrote:
>
>> So, do you think the problem is in the Xen backend drivers and to make
>> it working right in Xen the driver fix is needed?
>>
> Yes, the Xen blkback driver just submits I/O directly without using
> the right interfaces to force cache coherency. It might be relatively
> easy to hack a call in to flush all caches when it starts up, but given
> how it bypasses all abstractions it's almost impossible to give full
> coherency as if using the normal block device interfaces.
>
>
Ok, this way the fix to the drivers should be done. Thanks for your
investigation. I just forwarded your reply to other members of my team.

Thanks,
Michal