From: Dave Chinner <david@fromorbit.com>
To: Qu Wenruo <quwenruo@cn.fujitsu.com>
Cc: fstests@vger.kernel.org, btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: Is is possible to submit binary image as fstest test case?
Date: Fri, 7 Oct 2016 21:19:25 +1100 [thread overview]
Message-ID: <20161007101925.GW27872@dastard> (raw)
In-Reply-To: <f5f273e4-6d78-9ccd-64bf-480be7f05fbc@cn.fujitsu.com>
On Fri, Oct 07, 2016 at 05:26:27PM +0800, Qu Wenruo wrote:
>
>
> At 10/07/2016 05:18 PM, Dave Chinner wrote:
> >On Thu, Oct 06, 2016 at 04:12:56PM +0800, Qu Wenruo wrote:
> >>Hi,
> >>
> >>Just as the title says, for some case(OK, btrfs again) we need to
> >>catch a file system in special timing.
> >>
> >>In this specific case, we need to grab a btrfs image undergoing
> >>balancing, just before the balance finished.
> >>
> >>Although we can use flakey to drop all write, we still don't have
> >>method to catch the timing of the that transaction.
> >>
> >>
> >>On the other hand, we can tweak our local kernel, adding
> >>msleep()/message and dump the disk during the sleep.
> >>And the image I dumped can easily trigger btrfs kernel and user-space bug.
> >>
> >>So I'm wondering if I can just upload a zipped raw image as part of
> >>the test case?
> >
> >Preferably not. We've managed to avoid pre-built images in xfstests
> >for 15 years, so there'd have to be a really good reason to start
> >doing this, especially as once we open that floodgate we'll end up
> >with everyone wanting to do this and it will blow out the size of
> >the repository in now time.
>
> Makes sense.
> For btrfs-progs, which includes test images, it already takes about
> 77M, even we have tried our best to reduce image size.
>
> >
> >If the issue is just timing or being unable to trigger an error
> >at the right time, this is what error injection frameworks or
> >debug-only sysfs hooks are for. The XFS kernel code has both,
> >xfstests use both, and they pretty much do away with the need for
> >custom binary filesystem images for such testing...
>
> So again, btrfs is lacking infrastructure for debug.
> It seems that we can only rely on images out of xfstest tree,
That's the /wrong answer/. Go and implement debug infrastructure
that btrfs needs - if you wait for someone else to do it, it will
never get done and btrfs will never stabilise....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2016-10-07 10:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-06 8:12 Is is possible to submit binary image as fstest test case? Qu Wenruo
2016-10-06 12:29 ` Brian Foster
2016-10-06 19:24 ` Theodore Ts'o
2016-10-07 15:51 ` David Sterba
2016-10-07 9:18 ` Dave Chinner
2016-10-07 9:26 ` Qu Wenruo
2016-10-07 10:19 ` Dave Chinner [this message]
2016-10-07 16:16 ` David Sterba
2016-10-08 3:28 ` Qu Wenruo
2016-10-07 16:05 ` David Sterba
2016-10-09 23:56 ` Dave Chinner
2016-10-14 18:11 ` David Sterba
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