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From:   David Howells <dhowells@redhat.com>
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To:     Miklos Szeredi <miklos@szeredi.hu>
Cc:     dhowells@redhat.com, Ian Kent <raven@themaw.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Casey Schaufler <casey@schaufler-ca.com>,
        Stephen Smalley <sds@tycho.nsa.gov>,
        Nicolas Dichtel <nicolas.dichtel@6wind.com>,
        Christian Brauner <christian@brauner.io>, andres@anarazel.de,
        Jeff Layton <jlayton@redhat.com>, dray@redhat.com,
        Karel Zak <kzak@redhat.com>, keyrings@vger.kernel.org,
        Linux API <linux-api@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org,
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        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 13/17] watch_queue: Implement mount topology and attribute change notifications [ver #5]
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Date:   Mon, 03 Aug 2020 12:49:36 +0100
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Miklos Szeredi <miklos@szeredi.hu> wrote:

> OTOH mount notification is way smaller and IMO a more mature
> interface.  So just picking the unique ID patch into this set might
> make sense.

But userspace can't retrieve the unique ID without fsinfo() as things stand.

I'm changing it so that the fields are 64-bit, but initialised with the
existing mount ID in the notifications set.  The fsinfo set changes that to a
unique ID.  I'm tempted to make the unique IDs start at UINT_MAX+1 to
disambiguate them.

David