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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A3A0DC2D0E8 for ; Fri, 3 Apr 2020 11:11:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7C82620857 for ; Fri, 3 Apr 2020 11:11:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728099AbgDCLLq (ORCPT ); Fri, 3 Apr 2020 07:11:46 -0400 Received: from gardel.0pointer.net ([85.214.157.71]:51838 "EHLO gardel.0pointer.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727898AbgDCLLq (ORCPT ); Fri, 3 Apr 2020 07:11:46 -0400 Received: from gardel-login.0pointer.net (gardel.0pointer.net [IPv6:2a01:238:43ed:c300:10c3:bcf3:3266:da74]) by gardel.0pointer.net (Postfix) with ESMTP id 89E27E80689; Fri, 3 Apr 2020 13:11:44 +0200 (CEST) Received: by gardel-login.0pointer.net (Postfix, from userid 1000) id 20B1A1614E3; Fri, 3 Apr 2020 13:11:44 +0200 (CEST) Date: Fri, 3 Apr 2020 13:11:44 +0200 From: Lennart Poettering To: Ian Kent Cc: Miklos Szeredi , David Howells , Christian Brauner , Linus Torvalds , Al Viro , dray@redhat.com, Karel Zak , Miklos Szeredi , Steven Whitehouse , Jeff Layton , andres@anarazel.de, keyrings@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Aleksa Sarai Subject: Re: Upcoming: Notifications, FS notifications and fsinfo() Message-ID: <20200403111144.GB34663@gardel-login> References: <20200330211700.g7evnuvvjenq3fzm@wittgenstein> <1445647.1585576702@warthog.procyon.org.uk> <2418286.1585691572@warthog.procyon.org.uk> <20200401144109.GA29945@gardel-login> <2590640.1585757211@warthog.procyon.org.uk> <36e45eae8ad78f7b8889d9d03b8846e78d735d28.camel@themaw.net> <27994c53034c8f769ea063a54169317c3ee62c04.camel@themaw.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <27994c53034c8f769ea063a54169317c3ee62c04.camel@themaw.net> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fr, 03.04.20 09:44, Ian Kent (raven@themaw.net) wrote: > > Currently the only way to find the mount id from a path is by parsing > > /proc/self/fdinfo/$fd. It is trivial, however, to extend statx(2) to > > return it directly from a path. Also the mount notification queue > > that David implemented contains the mount ID of the changed mount. I would love to have the mount ID exposed via statx(). In systemd we generally try name_to_handle_at() to query the mount ID first. It returns both the actual fhandle and the mount ID after all, and we then throw the fhandle away. It's not available on all fs though, but it has the benefit that it works without procfs and on a number of older kernels that didn't expose the mnt id in fdinfo. Lennart -- Lennart Poettering, Berlin