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From:   Xiao Ni <xni@redhat.com>
Date:   Thu, 30 Mar 2023 08:10:45 +0800
Message-ID: <CALTww28X1NQecTY3Jbkz_wbHc_N7GOw3hJLEyb2YnxAmQ8PRFw@mail.gmail.com>
Subject: Re: [PATCH - mdadm] mdopen: always try create_named_array()
To:     NeilBrown <neilb@suse.de>
Cc:     Jes Sorensen <jes@trained-monkey.org>,
        Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>,
        Song Liu <song@kernel.org>,
        Linux regressions mailing list <regressions@lists.linux.dev>,
        linux-raid <linux-raid@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Nikolay Kichukov <hijacker@oldum.net>
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On Thu, Mar 30, 2023 at 5:52=E2=80=AFAM NeilBrown <neilb@suse.de> wrote:
>
> On Wed, 22 Mar 2023, NeilBrown wrote:
> > On Wed, 22 Mar 2023, Xiao Ni wrote:
> >
> > >
> > > Second, are there possibilities that the arguments "dev" and "name" o=
f
> > > function create_mddev
> > > are null at the same time?
> >
> > No.  For Build or Create, dev is never NULL.  For Assemble and
> > Incremental, name is never NULL.
> >
>
> I should clarify this a bit.  For Assemble and Incremental, "name" is
> never NULL *but* it might be an empty string.
> So:
>         if (name && name[0] =3D=3D 0)
>                 name =3D NULL;
>
> might cause it to become NULL.  So you cannot assume there is always
> either a valid "dev" or a valid "name".  "dev" might be NULL, and "name"
> might be "".
>
> NeilBrown
>

Hi Neil

The input argument name should be the metadata name. For incremental
and assemble, why are there possibilities that the metadata name is
invalid? A raid device should have a valid metadata name, right?


--=20
Best Regards
Xiao Ni