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Date:   Fri, 25 Mar 2022 10:10:49 +0100
From:   Karel Zak <kzak@redhat.com>
To:     Dave Chinner <david@fromorbit.com>
Cc:     Miklos Szeredi <miklos@szeredi.hu>,
        Miklos Szeredi <mszeredi@redhat.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Linux API <linux-api@vger.kernel.org>,
        linux-man <linux-man@vger.kernel.org>,
        LSM <linux-security-module@vger.kernel.org>,
        Ian Kent <raven@themaw.net>,
        David Howells <dhowells@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Christian Brauner <christian@brauner.io>,
        Amir Goldstein <amir73il@gmail.com>,
        James Bottomley <James.Bottomley@hansenpartnership.com>
Subject: Re: [RFC PATCH] getvalues(2) prototype
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On Fri, Mar 25, 2022 at 07:31:16AM +1100, Dave Chinner wrote:
> > What about other objects' attributes, statistics?   Remember this
> > started out as a way to replace /proc/self/mountinfo with something
> > that can query individual mount.
> 
> For individual mount info, why do we even need to query something in
> /proc? I mean, every open file in the mount has access to the mount
> and the underlying superblock, so why not just make the query
> namespace accessable from any open fd on that mount?


The current most problematic situation is in systemd. We get
generic notification (poll() on mountinfo) that something has been
modified in the mount table, and then we need to parse all the file
to get details.

So, the ideal solution would be notification that points to the FS
and interface to read information (e.g. getvalues()) about the FS.

    Karel


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