From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([222.73.24.84]:14270 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S934159Ab3HIGKR convert rfc822-to-8bit (ORCPT ); Fri, 9 Aug 2013 02:10:17 -0400 Message-ID: <52048770.40602@cn.fujitsu.com> Date: Fri, 09 Aug 2013 14:08:48 +0800 From: Wang Shilong MIME-Version: 1.0 To: Tomasz Chmielewski CC: "linux-btrfs@vger.kernel.org" Subject: Re: btrfs qgroup destroy -> ERROR: unable to create quota group: Device or resource busy References: <20130809133933.2fbfc6e4@virtall.com> <52048483.1010809@cn.fujitsu.com> <20130809140750.59832bc4@virtall.com> In-Reply-To: <20130809140750.59832bc4@virtall.com> Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 08/09/2013 02:07 PM, Tomasz Chmielewski wrote: > On Fri, 09 Aug 2013 13:56:19 +0800 > Wang Shilong wrote: > >>> It seems that btrfs automatically assigns a qgroup to newly created >>> snapshot/subvolume, but does not destroy the qgroup when the >>> subvolume is deleted. >> >> This should be implemented. And will soon. > > Great to hear (using 3.11-rc4 now). > > >>> So I've tried to destroy the unused qgroups, with mixed success. I >>> was able to destroy most of them, but some are still failing, i.e.: >>> >>> # btrfs qgroup destroy 4494 /mnt/lxc1 >>> ERROR: unable to create quota group: Device or resource busy >> >> Just remove qgroup（4494）'s parent qgroup. then it can be removed. >> Anyway, i think this is unnecessary. > > I don't want to remove the parent qgroup, as it's in use by other subvolumes: > > # /usr/src/qgroup/btrfs-progs/btrfs qgroup show -c /mnt/lxc1 | grep 4494 > > 0/4494 839516160 18446744073709481984 --- <------ want to remove only this one > > 13/1 2142674944 2142674944 0/3973,0/3974,0/3978,0/3981,0/4355,0/4373,0/4398,0/4400,0/4401,0/4427,0/4448,0/4449,0/4457,0/4458,0/4475,0/4476,0/4487,0/4488,0/4489,0/4490,0/4491,0/4492,0/4493,0/4494,0/4495,0/4496,0/4497,0/4498,0/4499,0/4506,0/4507,0/4518 > > > Parent qgroup 13/1 makes accounting for other qgroups - therefore, I don't want to remove it. Sorry, you must destroy relation between 13/1 and 4494. then you can remove it. thanks, Wang > > > > BTW, "/usr/src/qgroup/btrfs-progs/btrfs" is from http://github.com/miaoxie/btrfs-progs.git, to support printing parent/child qgroup IDs. > > Note it shows different values than btrfs from official repository - is that expected? > > # /usr/src/qgroup/btrfs-progs/btrfs qgroup show /mnt/lxc1 | grep 4494 > 0/4494 839516160 18446744073709481984 > > # btrfs qgroup show /mnt/lxc1 | grep 4494 > 0/4494 839516160 -69632 >