From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F2FCC04AB5 for ; Thu, 6 Jun 2019 22:38:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F96D20868 for ; Thu, 6 Jun 2019 22:38:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727711AbfFFWiY convert rfc822-to-8bit (ORCPT ); Thu, 6 Jun 2019 18:38:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37018 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726538AbfFFWiX (ORCPT ); Thu, 6 Jun 2019 18:38:23 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C91BE128B5; Thu, 6 Jun 2019 22:38:15 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-173.rdu2.redhat.com [10.10.120.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id B67827840D; Thu, 6 Jun 2019 22:38:02 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <155981411940.17513.7137844619951358374.stgit@warthog.procyon.org.uk> <3813.1559827003@warthog.procyon.org.uk> <8382af23-548c-f162-0e82-11e308049735@tycho.nsa.gov> <0eb007c5-b4a0-9384-d915-37b0e5a158bf@schaufler-ca.com> <07e92045-2d80-8573-4d36-643deeaff9ec@schaufler-ca.com> <23611.1559855827@warthog.procyon.org.uk> To: Andy Lutomirski Cc: dhowells@redhat.com, Andy Lutomirski , Casey Schaufler , Stephen Smalley , Al Viro , Greg Kroah-Hartman , USB list , raven@themaw.net, Linux FS Devel , Linux API , linux-block@vger.kernel.org, keyrings@vger.kernel.org, LSM List , LKML , Paul Moore Subject: Re: [RFC][PATCH 00/10] Mount, FS, Block and Keyrings notifications [ver #3] MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Date: Thu, 06 Jun 2019 23:38:01 +0100 Message-ID: <30567.1559860681@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Thu, 06 Jun 2019 22:38:23 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Andy Lutomirski wrote: > I mean: are there cases where some action generates a notification but does > not otherwise have an effect visible to the users who can receive the > notification. It looks like the answer is probably “no”, which is good. mount_notify(). You can get a notification that someone altered the mount topology (eg. by mounting something). A process receiving a notification could then use fsinfo(), say, to reread the mount topology tree, find out where the new mount is and wander over there to have a look - assuming they have the permissions for pathwalk to succeed. David