On Thu, Sep 29, 2022 at 02:04:00PM +0200, David Sterba wrote:
> On Thu, Sep 29, 2022 at 02:01:06PM +0800, Zorro Lang wrote:
> > On Thu, Sep 29, 2022 at 01:19:25PM +0900, Naohiro Aota wrote:
> > > A ZNS device limits the number of active zones, which is the number of
> > > zones can be written at the same time. To deal with the limit, btrfs's
> > > zoned mode tracks which zone (corresponds to a block group on the SINGLE
> > > profile) is active, and finish a zone if necessary.
> > >
> > > This test checks if the active zone tracking and the finishing of zones
> > > works properly. First, it fills <number of max active zones> zones
> > > mostly. And, run some data/metadata stress workload to force btrfs to use a
> > > new zone.
> > >
> > > This test fails on an older kernel (e.g, 5.18.2) like below.
> > >
> > > btrfs/292
> > > [failed, exit status 1]- output mismatch (see /host/btrfs/292.out.bad)
> > > --- tests/btrfs/292.out 2022-09-15 07:52:18.000000000 +0000
> > > +++ /host/btrfs/292.out.bad 2022-09-15 07:59:14.290967793 +0000
> > > @@ -1,2 +1,5 @@
> > > QA output created by 292
> > > -Silence is golden
> > > +stress_data_bgs failed
> > > +stress_data_bgs_2 failed
> > > +failed: '/bin/btrfs subvolume snapshot /mnt/scratch /mnt/scratch/snap825'
> > > +(see /host/btrfs/292.full for details)
> > > ...
> > > (Run 'diff -u /var/lib/xfstests/tests/btrfs/292.out /host/btrfs/292.out.bad' to see the entire diff)
> > >
> > > The failure is fixed with a series "btrfs: zoned: fix active zone tracking
> > > issues" [1] (upstream commits from 65ea1b66482f ("block: add bdev_max_segments()
> > > helper") to 2ce543f47843 ("btrfs: zoned: wait until zone is finished when
> > > allocation didn't progress")).
> >
> > If this's a regression test case for known fix, we'd better to use:
> > _fixed_by_kernel_commit 65ea1b66482f block: add bdev_max_segments (patchset)
>
> This is very misleading as the commit only adds a helper that's used in
> later commits. If anything, the last commit in the series should be
> mentioned.
Sure, I just gave an example, you learned about that patchset more than me, so
feel free to pick up a proper commit and description :)
>
