Re: [PATCH] xfs: test log recovery for extent frees right after growfs

[Brian Foster <bfoster@redhat.com>]

On Tue, Sep 10, 2024 at 05:10:53PM +0200, Christoph Hellwig wrote:
> On Tue, Sep 10, 2024 at 10:19:50AM -0400, Brian Foster wrote:
> > No real issue with the test, but I wonder if we could do something more
> > generic. Various XFS shutdown and log recovery issues went undetected
> > for a while until we started adding more of the generic stress tests
> > currently categorized in the recoveryloop group.
> > 
> > So for example, I'm wondering if you took something like generic/388 or
> > 475 and modified it to start with a smallish fs, grew it in 1GB or
> > whatever increments on each loop iteration, and then ran the same
> > generic stress/timeout/shutdown/recovery sequence, would that eventually
> > reproduce the issue you've fixed? I don't think reproducibility would
> > need to be 100% for the test to be useful, fwiw.
> > 
> > Note that I'm assuming we don't have something like that already. I see
> > growfs and shutdown tests in tests/xfs/group.list, but nothing in both
> > groups and I haven't looked through the individual tests. Just a
> > thought.
> 
> It turns out reproducing this bug was surprisingly complicated.
> After a growfs we can now dip into reserves that made the test1
> file start filling up the existing AGs first for a while, and thus
> the error injection would hit on that and never even reach a new
> AG.
> 
> So while agree with your sentiment and like the highlevel idea, I
> suspect it will need a fair amount of work to actually be useful.
> Right now I'm too busy with various projects to look into it
> unfortunately.
> 

Fair enough, maybe I'll play with it a bit when I have some more time.

Brian