Re: [Xen-devel] [PATCHv3] QEMU(upstream): Disable xen's use of O_DIRECT by default as it results in crashes.

[George Dunlap <george.dunlap@xxxxxxxxxxxxx>]

On 11/03/13 14:02, Alex Bligh wrote:
> --On 8 March 2013 12:54:16 +0000 George Dunlap
> <George.Dunlap@xxxxxxxxxxxxx> wrote:
>
> > On Fri, Mar 8, 2013 at 11:40 AM, Alex Bligh <alex@xxxxxxxxxxx> wrote:
> > > Due to what is almost certainly a kernel bug, writes with
> > > O_DIRECT may continue to reference the page after the write
> > > has been marked as completed, particularly in the case of
> > > TCP retransmit. In other scenarios, this "merely" risks
> > > data corruption on the write, but with Xen pages from domU
> > > are only transiently mapped into dom0's memory, resulting
> > > in kernel panics when they are subsequently accessed.
> > >
> > > This brings PV devices in line with emulated devices. Removing
> > > O_DIRECT is safe as barrier operations are now correctly passed
> > > through.
> > Not qualified to comment on the technical merits of the patch, but re
> > the commit message:
> >
> > Acked-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
> Any further thoughts on this one?
I believe that Stefano is the person to commit it, but he's on holiday 
for two weeks.
 -George

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