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From:   Miklos Szeredi <mszeredi@redhat.com>
Date:   Mon, 24 Jun 2019 12:53:34 +0200
Message-ID: <CAOssrKc=1FDpOzgpzO9dtkk2sTyq2VVL5ajqgowh4PafzQQJBg@mail.gmail.com>
Subject: Re: [PATCH 05/13] vfs: don't parse "silent" option
To:     David Howells <dhowells@redhat.com>
Cc:     Ian Kent <raven@themaw.net>, Al Viro <viro@zeniv.linux.org.uk>,
        Linux API <linux-api@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        lkml <linux-kernel@vger.kernel.org>
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On Mon, Jun 24, 2019 at 12:44 PM Miklos Szeredi <mszeredi@redhat.com> wrote:
>
> On Mon, Jun 24, 2019 at 12:36 PM David Howells <dhowells@redhat.com> wrote:
> >
> > Miklos Szeredi <mszeredi@redhat.com> wrote:
> >
> > > What I'm saying is that with a new interface the rules need not follow
> > > the rules of the old interface, because at the start no one is using
> > > the new interface, so no chance of breaking anything.
> >
> > Er. No.  That's not true, since the old interface comes through the new one.
>
> No, old interface sets SB_* directly from arg 4 of mount(2) and not
> via parsing arg 5.

See also 9p mess up of "posixacl" handling *on the old interface* due
to exactly because the internal API doesn't differentiate between
options coming from the old interface and ones coming from the new.

So you are right that there's breakage, but it's due to the fact that
common code parses anything, and not because it doesn't.

Thanks,
Miklos