From mboxrd@z Thu Jan 1 00:00:00 1970 From: Karel Zak Date: Tue, 31 Mar 2020 09:49:30 +0000 Subject: Re: Upcoming: Notifications, FS notifications and fsinfo() Message-Id: <20200331094930.3aipm3zrydpqqhms@ws.net.home> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit List-Id: References: <1445647.1585576702@warthog.procyon.org.uk> <20200330211700.g7evnuvvjenq3fzm@wittgenstein> <20200331083430.kserp35qabnxvths@ws.net.home> In-Reply-To: To: Miklos Szeredi Cc: Christian Brauner , David Howells , Linus Torvalds , Al Viro , dray@redhat.com, Miklos Szeredi , Steven Whitehouse , Jeff Layton , Ian Kent , andres@anarazel.de, keyrings@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Lennart Poettering , Aleksa Sarai On Tue, Mar 31, 2020 at 10:56:35AM +0200, Miklos Szeredi wrote: > I think we are approaching this from the wrong end. Let's just > ignore all of the proposed interfaces for now and only concentrate on > what this will be used for. > > Start with a set of use cases by all interested parties. E.g. > > - systemd wants to keep track attached mounts in a namespace, as well > as new detached mounts created by fsmount() > > - systemd need to keep information (such as parent, children, mount > flags, fs options, etc) up to date on any change of topology or > attributes. > > - util linux needs to display the topology and state of mounts in the > system that corresponds to a consistent state that set of mounts - like systemd we also need in mount/umount to query one mountpoint rather than parse all /proc/self/mountinfo Karel -- Karel Zak http://karelzak.blogspot.com 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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 77FF0C43331 for ; Tue, 31 Mar 2020 09:49:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4EE31206EB for ; Tue, 31 Mar 2020 09:49:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NqjYVLaC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730161AbgCaJto (ORCPT ); Tue, 31 Mar 2020 05:49:44 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:21695 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730131AbgCaJtn (ORCPT ); Tue, 31 Mar 2020 05:49:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585648182; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Z4v/YtSm7khSMtma48XmYXMI66/O3qRGCFmAxLMn+2U=; b=NqjYVLaCD7agG9fI4rD9iLT4+kBSb2mKLUv53oxUlHQn5vWcLsuAUfe/WUX6itl6X6DJLw r0oKHhNMH+V8idDnUbLhKl4kN/2bsacxbv0zG+LwZcpPuKFojeZwKebsdTRw62OM1tfhE3 SmIP7JpBr6Bw4JQLybDIH00zaOU3ck4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-479-wsmh7QxlMIexmPjb_Lr0Pw-1; Tue, 31 Mar 2020 05:49:38 -0400 X-MC-Unique: wsmh7QxlMIexmPjb_Lr0Pw-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7F5621005509; Tue, 31 Mar 2020 09:49:36 +0000 (UTC) Received: from ws.net.home (unknown [10.40.194.51]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BB62598A21; Tue, 31 Mar 2020 09:49:32 +0000 (UTC) Date: Tue, 31 Mar 2020 11:49:30 +0200 From: Karel Zak To: Miklos Szeredi Cc: Christian Brauner , David Howells , Linus Torvalds , Al Viro , dray@redhat.com, Miklos Szeredi , Steven Whitehouse , Jeff Layton , Ian Kent , andres@anarazel.de, keyrings@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Lennart Poettering , Aleksa Sarai Subject: Re: Upcoming: Notifications, FS notifications and fsinfo() Message-ID: <20200331094930.3aipm3zrydpqqhms@ws.net.home> References: <1445647.1585576702@warthog.procyon.org.uk> <20200330211700.g7evnuvvjenq3fzm@wittgenstein> <20200331083430.kserp35qabnxvths@ws.net.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 31, 2020 at 10:56:35AM +0200, Miklos Szeredi wrote: > I think we are approaching this from the wrong end. Let's just > ignore all of the proposed interfaces for now and only concentrate on > what this will be used for. > > Start with a set of use cases by all interested parties. E.g. > > - systemd wants to keep track attached mounts in a namespace, as well > as new detached mounts created by fsmount() > > - systemd need to keep information (such as parent, children, mount > flags, fs options, etc) up to date on any change of topology or > attributes. > > - util linux needs to display the topology and state of mounts in the > system that corresponds to a consistent state that set of mounts - like systemd we also need in mount/umount to query one mountpoint rather than parse all /proc/self/mountinfo Karel -- Karel Zak http://karelzak.blogspot.com