Re: Wrong DIF guard tag on ext2 write

From: Christof Schmitt
Date: Tue Jun 08 2010 - 03:15:45 EST


On Mon, Jun 07, 2010 at 01:40:21PM -0400, Martin K. Petersen wrote:
> >>>>> "Boaz" == Boaz Harrosh <bharrosh@xxxxxxxxxxx> writes:
>
> Boaz> Do you remember some performance numbers that show degradation /
> Boaz> sameness?
>
> Boaz> What type of work loads?
>
> I haven't been using XFS much for over a year. I'm using an internal
> async I/O tool and btrfs for most of my DIX/DIF testing these days.
>
> But my original changes were along the lines of what Jan mentioned
> earlier (hooking into page_mkwrite and waiting for writeback. I could
> have sworn that I only did it for ext[23] and that XFS waited out of the
> box but git proves me wrong). Anyway, I'll try to get some benchmarking
> happening later this week.

Is there a patch with this change available somewhere? It might be
useful to patch a kernel with this XFS change for reliable DIF/DIX
testing.

> This won't fix things completely, though. ext2fs, for instance,
> frequently changes metadata buffers in flight so it trips the guard
> check in no time.
>
> --
> Martin K. Petersen Oracle Linux Engineering
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