From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from azure.uno.uk.net ([95.172.254.11]:46566 "EHLO azure.uno.uk.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753847AbdHWMLy (ORCPT ); Wed, 23 Aug 2017 08:11:54 -0400 Received: from ty.sabi.co.uk ([95.172.230.208]:39896) by azure.uno.uk.net with esmtpsa (TLSv1.2:DHE-RSA-AES128-SHA:128) (Exim 4.89) (envelope-from ) id 1dkUVk-00086b-EE for linux-btrfs@vger.kernel.org; Wed, 23 Aug 2017 13:11:52 +0100 Received: from from [127.0.0.1] (helo=tree.ty.sabi.co.uk) by ty.sabi.co.UK with esmtps(Cipher TLS1.2:DHE_RSA_AES_128_CBC_SHA1:128)(Exim 4.82 3) id 1dkU3B-0005gw-8o for ; Wed, 23 Aug 2017 12:42:21 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <22941.27164.739577.517915@tree.ty.sabi.co.uk> Date: Wed, 23 Aug 2017 12:42:20 +0100 To: Linux fs Btrfs Subject: Re: user snapshots In-Reply-To: <20170823072048.GB28319@rus.uni-stuttgart.de> References: <20170822142451.GI14804@rus.uni-stuttgart.de> <20170822214531.44538589@natsu> <20170822165725.GL14804@rus.uni-stuttgart.de> <20170822180155.GM14804@rus.uni-stuttgart.de> <22940.31139.194399.982315@tree.ty.sabi.co.uk> <20170822215343.GP14804@rus.uni-stuttgart.de> <124CEBB9-BF23-4688-B23C-294EDCAD27AA@demfloro.ru> <20170823101635.114d02d2@job> <20170823072048.GB28319@rus.uni-stuttgart.de> From: pg@btrfs.list.sabi.co.UK (Peter Grandi) Sender: linux-btrfs-owner@vger.kernel.org List-ID: > So, still: What is the problem with user_subvol_rm_allowed? As usual, it is complicated: mostly that while subvol creation is very cheap, subvol deletion can be very expensive. But then so can be creating many snapshots, as in this: https://www.spinics.net/lists/linux-btrfs/msg62760.html Also that deleting a subvol can delete a lot of stuff "inadvertently", including things that the user could not delete using UNIX style permissions. But it many of the Btrfs semantics feel a bit "arbitrary" in part because they break new ground, in part because happenstance. http://linux-btrfs.vger.kernel.narkive.com/eTtmsQdL/patch-1-2-btrfs-don-t-check-the-permission-of-the-subvolume-which-we-want-to-delete http://linux-btrfs.vger.kernel.narkive.com/nR17xtw7/patch-btrfs-allow-subvol-deletion-by-unprivileged-user-with-o-user-subvol-rm-allowed