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Date:   Tue, 17 Dec 2019 04:17:31 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Miklos Szeredi <miklos@szeredi.hu>
Cc:     Miklos Szeredi <mszeredi@redhat.com>, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 12/12] vfs: don't parse "silent" option
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On Tue, Dec 17, 2019 at 05:12:05AM +0100, Miklos Szeredi wrote:
> On Tue, Dec 17, 2019 at 4:37 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > On Thu, Nov 28, 2019 at 04:59:40PM +0100, Miklos Szeredi wrote:
> > > While this is a standard option as documented in mount(8), it is ignored by
> > > most filesystems.  So reject, unless filesystem explicitly wants to handle
> > > it.
> > >
> > > The exception is unconverted filesystems, where it is unknown if the
> > > filesystem handles this or not.
> > >
> > > Any implementation, such as mount(8), that needs to parse this option
> > > without failing can simply ignore the return value from fsconfig().
> >
> > Unless I'm missing something, that will mean that having it in /etc/fstab
> > for a converted filesystem (xfs, for example) will fail when booting
> > new kernel with existing /sbin/mount.  Doesn't sound like a good idea...
> 
> Nope, the mount(2) case is not changed (see second hunk).

How would mounting XFS end up calling legacy_parse_param(), rather than
the expected generic_parse_monolithic() -> vfs_parse_fs_string() ->
vfs_parse_fs_param() -> xfs_fc_parse_param()?