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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC0BAC4332F for ; Mon, 6 Nov 2023 17:10:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231685AbjKFRKk (ORCPT ); Mon, 6 Nov 2023 12:10:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231669AbjKFRKi (ORCPT ); Mon, 6 Nov 2023 12:10:38 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF8D01BC; Mon, 6 Nov 2023 09:10:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=2QgiGpxHYkLHxfAiCc/bL2CX3SUtRZj7hPmY4pr3NfU=; b=F7DXaqgWSc5V4Rc5RE1Sj6vPsz 9PrOOcXUwfxEShyi0lQ+5yTPHgWnTRAsq/crfqs7w1uwLd1CuEwOhqFoQaFBpKOB/dn5eXA2svEiA yFjVR/dew3gYomgNSZ+AIGx2iT3i0hmxcmVp08Emlv5sOf3QPnS/ildCVXCSLwDXScqgGLV4NlWCQ xWh9LMA5a0qcynnKi/1ual93n34+HltL21sFtJ685VGb885Y5MXnjW4Z1rUGcfWwuxEfkNTwBsMRb j9n8Hr6jNasr6Nw75WthfqPXrIQxfxtp+PhynA1TB03hjPWkWM3NjkUT9X5tqA8ll7O9l1BcJBhxQ ROPxgHig==; Received: from hch by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1r037M-00HCCv-1X; Mon, 06 Nov 2023 17:10:28 +0000 Date: Mon, 6 Nov 2023 09:10:28 -0800 From: Christoph Hellwig To: Christian Brauner Cc: Christoph Hellwig , Qu Wenruo , Josef Bacik , Amir Goldstein , Jan Kara , Chris Mason , David Sterba , linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 0/3] fanotify support for btrfs sub-volumes Message-ID: References: <20231102051349.GA3292886@perftesting> <20231102-schafsfell-denkzettel-08da41113e24@brauner> <20231103-kursleiter-proklamieren-aae0a02aa1a4@brauner> <20231106-fragment-geweigert-1d80138523e5@brauner> <49454bf2-af6e-4dcf-b9a1-22acbfdc756d@gmx.com> <20231106-postfach-erhoffen-9a247559e10d@brauner> <20231106-datei-filzstift-c62abf899f8f@brauner> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231106-datei-filzstift-c62abf899f8f@brauner> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Mon, Nov 06, 2023 at 02:05:45PM +0100, Christian Brauner wrote: > > > I think spending time engaging this claim isn't worth it. This is just > > > easily falsifiable via a simple grep for btrfs in systemd, lxc, runc, > > > util-linux. > > > > Myabe you need to get our of your little bubble. There is plenty of > > Unnecessary personal comment, let alone that I'm not in any specific > bubble just because I'm trying to be aware of what is currently going on > in userspace. Maybe you're just taking it to personal? A place where systemd, lxc, runc, and util-linux are "all software" is a very much a bubble as you won't find much userspace that stays more uptodate with particular quirks of modern Linux features. > Whatever you do here: vfsmounts or any other solution will force changes > in userspace on a larger scale and changes to the filesystem itself. If > you accommodate tar then you are fscking over other parts of userspace > which are equally important. There is no free lunch. It works for everything that knows that Linux mountpoint as exposed in /proc/mounts and proc/self/mountinfo corresponds to the posix definition of a mount point, and that one used on basically every other unix system. It might not work as-is for software that actually particularly knows how to manage btrfs subvolumes, but those are, by defintion, not the problem anyway. It's thinkgs like backup tools that run into random ino_t duplicates. That's an example we had in the past, and I would be absolutely not be surprised if there is more than more of those hiding right now.