From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4902B200A5 for ; Mon, 6 Nov 2023 13:05:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RjpR4oWz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2531C433C9; Mon, 6 Nov 2023 13:05:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1699275951; bh=ezjRNz36YPeF/BTqJXA0UO74QbjRLxn+r/wcNsolT+s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RjpR4oWzNvlwKDQ+AO6TdkFR+N4vQ7oqjQyKM2ft4f4pRzV8gVvojWbtfeZQFW9is hx1OsboYheS9qF/boy1n6uy6X7qAVNKE9ZMR5JNheiZ+TMaX9ixEar8NLmUnBHDz93 wQ7jbb02Q8nm61XBXHa3T8hwphs+p03oSOurU29GMvaze96zgNkuF2JWuKIIQH2WrU 266fmKN5x6Pmgp61W3WtO9FKtumv8k8rfRKM4h5Pz+kIB+Saa28CwJqYvR4M5GMYeu YDYpiyKiLA972OKZws7tvWQITgOkxqbJfXxcDFm6C+ZzNyjNLy6RBagH5rcUekaaPN K3C5XxT2IZiSg== Date: Mon, 6 Nov 2023 14:05:45 +0100 From: Christian Brauner To: Christoph Hellwig Cc: 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: <20231106-datei-filzstift-c62abf899f8f@brauner> References: <20231101-neigen-storch-cde3b0671902@brauner> <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> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Mon, Nov 06, 2023 at 04:30:57AM -0800, Christoph Hellwig wrote: > On Mon, Nov 06, 2023 at 11:59:22AM +0100, Christian Brauner wrote: > > > > They > > > > all know that btrfs subvolumes are special. They will need to know that > > > > btrfs subvolumes are special in the future even if they were vfsmounts. > > > > They would likely end up with another kind of confusion because suddenly > > > > vfsmounts have device numbers that aren't associated with the superblock > > > > that vfsmount belongs to. > > > > > > This looks like you are asking user space programs (especially legacy > > > ones) to do special handling for btrfs, which I don't believe is the > > > standard way. > > > > 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. > code outside the fast moving Linux Desktop and containers bubbles that > takes decades to adopt to new file systems, and then it'll take time > again to find bugs exposed by such odd behavior. So what? 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. Second, we're not going to shy away from changes just because it takes long for them to be adopted. That's just not a position for us to take.