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From:   Miklos Szeredi <miklos@szeredi.hu>
Date:   Thu, 2 Apr 2020 17:24:32 +0200
Message-ID: <CAJfpegv4=wAi+mH32pHM9g8gk+JGESWa25n04BwfnkhVBf=3rA@mail.gmail.com>
Subject: Re: Upcoming: Notifications, FS notifications and fsinfo()
To:     David Howells <dhowells@redhat.com>
Cc:     Karel Zak <kzak@redhat.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>, dray@redhat.com,
        Miklos Szeredi <mszeredi@redhat.com>,
        Steven Whitehouse <swhiteho@redhat.com>,
        Jeff Layton <jlayton@redhat.com>, Ian Kent <raven@themaw.net>,
        andres@anarazel.de, keyrings@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Lennart Poettering <lennart@poettering.net>,
        Aleksa Sarai <cyphar@cyphar.com>
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On Thu, Apr 2, 2020 at 5:23 PM David Howells <dhowells@redhat.com> wrote:
>
> Miklos Szeredi <miklos@szeredi.hu> wrote:
>
> > > > Not sure what you mean.  I think it shows precisely the information
> > > > Karel asked for.
> > >
> > > It's not atomic.
> >
> > Yes it is.
>
> No, it really isn't - though it could be made so.
>
> ext4_show_mount(), for example, doesn't lock against "mount -o remount", so
> the configuration can be changing whilst it's being rendered to text.

Does s_umount nest inside namespace_sem?  I really don't see the
relation of those locks.

Thanks,
Miklos