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Date:   Thu, 26 Oct 2023 22:46:01 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Josef Bacik <josef@toxicpanda.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Amir Goldstein <amir73il@gmail.com>, Jan Kara <jack@suse.cz>,
        Christian Brauner <brauner@kernel.org>,
        Chris Mason <clm@fb.com>, David Sterba <dsterba@suse.com>,
        linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 0/3] fanotify support for btrfs sub-volumes
Message-ID: <ZTtOmWEx5neNKkez@infradead.org>
References: <20231025135048.36153-1-amir73il@gmail.com>
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 <20231025210654.GA2892534@perftesting>
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I think you're missing the point.  A bunch of statx fields might be
useful, but they are not solving the problem.  What you need is
a separate vfsmount per subvolume so that userspace sees when it
is crossing into it.  We probably can't force this onto existing
users, so it needs a mount, or even better on-disk option but without
that we're not getting anywhere.