Re: [PATCH v2] md/raid0: Ignore RAID0 layout if the second zone has only one device

["NeilBrown" <neilb@suse.de>]

On Fri, 15 Apr 2022, Song Liu wrote:
> On Tue, Apr 12, 2022 at 11:54 PM Pascal Hambourg <pascal@plouf.fr.eu.org> wrote:
> >
> > The RAID0 layout is irrelevant if all members have the same size so the
> > array has only one zone. It is *also* irrelevant if the array has two
> > zones and the second zone has only one device, for example if the array
> > has two members of different sizes.
> >
> > So in that case it makes sense to allow assembly even when the layout is
> > undefined, like what is done when the array has only one zone.
> >
> > Reviewed-By: NeilBrown <neilb@suse.de>
> > Signed-off-by: Pascal Hambourg <pascal@plouf.fr.eu.org>
> 
> Thanks for the patch and thanks Neil for the review.
> 
> Applied to md-next with two minor changes:
> 
> s/ENOTSUPP/EOPNOTSUPP/

Why did you change the error code that was returned?  If you want to do
that it should be a separate patch with explanation.

> s/Reviewed-By/Review-by/

Do you mean s/Reviewed-By/Reviewed-by/  - i.e. change the B to b ??

Since v5.0 there have only be 5 "Review-by" and over 100,000
"Reviewed-by" (and about 100 "Reviewed-By").

Thanks,
NeilBrown


> 
> Thanks,
> Song
> 
> > ---
> >
> > Changes since v1:
> > - add missing Signed-off-by
> > - add missing subsystem maintainer in recipients
> >
> > ---
> >   drivers/md/raid0.c | 31 ++++++++++++++++---------------
> >   1 file changed, 16 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> > index b21e101183f4..7623811cc11c 100644
> > --- a/drivers/md/raid0.c
> > +++ b/drivers/md/raid0.c
> > @@ -128,21 +128,6 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
> >         pr_debug("md/raid0:%s: FINAL %d zones\n",
> >                  mdname(mddev), conf->nr_strip_zones);
> >
> > -       if (conf->nr_strip_zones == 1) {
> > -               conf->layout = RAID0_ORIG_LAYOUT;
> > -       } else if (mddev->layout == RAID0_ORIG_LAYOUT ||
> > -                  mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
> > -               conf->layout = mddev->layout;
> > -       } else if (default_layout == RAID0_ORIG_LAYOUT ||
> > -                  default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
> > -               conf->layout = default_layout;
> > -       } else {
> > -               pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n",
> > -                      mdname(mddev));
> > -               pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n");
> > -               err = -ENOTSUPP;
> > -               goto abort;
> > -       }
> >         /*
> >          * now since we have the hard sector sizes, we can make sure
> >          * chunk size is a multiple of that sector size
> > @@ -273,6 +258,22 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
> >                          (unsigned long long)smallest->sectors);
> >         }
> >
> > +       if (conf->nr_strip_zones == 1 || conf->strip_zone[1].nb_dev == 1) {
> > +               conf->layout = RAID0_ORIG_LAYOUT;
> > +       } else if (mddev->layout == RAID0_ORIG_LAYOUT ||
> > +                  mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
> > +               conf->layout = mddev->layout;
> > +       } else if (default_layout == RAID0_ORIG_LAYOUT ||
> > +                  default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
> > +               conf->layout = default_layout;
> > +       } else {
> > +               pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n",
> > +                      mdname(mddev));
> > +               pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n");
> > +               err = -ENOTSUPP;
> > +               goto abort;
> > +       }
> > +
> >         pr_debug("md/raid0:%s: done.\n", mdname(mddev));
> >         *private_conf = conf;
> >
> > --
> > 2.11.0
> >
>