Re: [PATCH] aoe: end barrier bios with EOPNOTSUPP

Ed Cashin
2009-09-09T21:24:53Z

On Wed Sep 9 16:59:30 EDT 2009, jens.axboe@oracle.com wrote:
> On Wed, Sep 09 2009, Ed Cashin wrote:
...
> > To implement the barrier, [aoe] would stop generating new AoE write
> > commands, wait for AoE write responses for all the outstanding write
> > commands, issue the ATA cache flush command, wait for the response to
> > the flush, and then resume normal activity.
>
> That's how barriers work with sata to begin with, so I'd very much
> recommend that you do the same in aoe instead of just not supporting it.

This patch with EOPNOTSUPP just fixes the regression in 2.6.31-rc9.

A patch adding support for barriers would be nice. Since I have
limited time I tried to motivate that work by using the torture tests
that Chris Mason (I believe it was) posted a while ago, but I could
not get any problems to manifest using that torture test.

If I had a reproducable problem case that the barrier implementation
could fix, it would be very helpful.

--
Ed