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Date:   Wed, 1 Apr 2020 11:04:45 +0200
From:   Karel Zak <kzak@redhat.com>
To:     David Howells <dhowells@redhat.com>
Cc:     Christian Brauner <christian.brauner@ubuntu.com>,
        torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
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        keyrings@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, lennart@poettering.net,
        cyphar@cyphar.com
Subject: Re: Upcoming: Notifications, FS notifications and fsinfo()
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On Tue, Mar 31, 2020 at 10:52:52PM +0100, David Howells wrote:
> Christian Brauner <christian.brauner@ubuntu.com> wrote:
> 
> > querying all properties of a mount atomically all-at-once,
> 
> I don't actually offer that, per se.
> 
> Having an atomic all-at-once query for a single mount is actually quite a
> burden on the system.  There's potentially a lot of state involved, much of
> which you don't necessarily need.

If all means "all possible attributes" than it is unnecessary, for
example ext4 timestamps or volume uuid/label are rarely necessary.
We usually need together (as consistent set):

    source
    mountpoint
    FS type
    FS root (FSINFO_ATTR_MOUNT_PATH)
    FS options (FSINFO_ATTR_CONFIGURATION)
    VFS attributes
    VFS propagation flags
    mount ID
    parent ID
    devno (or maj:min)

 Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com