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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 039EDC433DF for ; Mon, 8 Jun 2020 23:30:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4E7020775 for ; Mon, 8 Jun 2020 23:30:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591659032; bh=Ljoi6SPtp9BQsszabiJzv6FOpQKYVjz22TNrx7xiH/E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Xcpr9PlLqmVb/9wxe3qz45Amq9OB2tfJUCG83f9g4DcPcW2D5nAwhyREFV3zddeG+ uqlir7HFqcmodMCNY5DVhADuN9bJK4HFRuuTneg6CS1wNn8bvkamct2bRgt+DvKgON EZvJQ1QhO1DBny0QkwTAYVAtSDLOVOU/aPfw9ejo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732376AbgFHXaa (ORCPT ); Mon, 8 Jun 2020 19:30:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:50728 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387508AbgFHXYf (ORCPT ); Mon, 8 Jun 2020 19:24:35 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DF1BC20899; Mon, 8 Jun 2020 23:24:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658674; bh=Ljoi6SPtp9BQsszabiJzv6FOpQKYVjz22TNrx7xiH/E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ejASoqjemsbEHFaqD9mmmftna/M6mOvEPCS4OBNBUVuG331pa4Th9gdDRc6HJx/JG g2wZitxGYlHqIudqo6TYCXh+TD626p/vUYyaey4f7BFQ6AvnLT5O3wfGyKyjs3TAMh QVFW6h7pv6IP+Qyzqe7zgxug5hdSdi5qg78fxewQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Qu Wenruo , Josef Bacik , David Sterba , Sasha Levin , linux-btrfs@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 086/106] btrfs: qgroup: mark qgroup inconsistent if we're inherting snapshot to a new qgroup Date: Mon, 8 Jun 2020 19:22:18 -0400 Message-Id: <20200608232238.3368589-86-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608232238.3368589-1-sashal@kernel.org> References: <20200608232238.3368589-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Qu Wenruo [ Upstream commit cbab8ade585a18c4334b085564d9d046e01a3f70 ] [BUG] For the following operation, qgroup is guaranteed to be screwed up due to snapshot adding to a new qgroup: # mkfs.btrfs -f $dev # mount $dev $mnt # btrfs qgroup en $mnt # btrfs subv create $mnt/src # xfs_io -f -c "pwrite 0 1m" $mnt/src/file # sync # btrfs qgroup create 1/0 $mnt/src # btrfs subv snapshot -i 1/0 $mnt/src $mnt/snapshot # btrfs qgroup show -prce $mnt/src qgroupid rfer excl max_rfer max_excl parent child -------- ---- ---- -------- -------- ------ ----- 0/5 16.00KiB 16.00KiB none none --- --- 0/257 1.02MiB 16.00KiB none none --- --- 0/258 1.02MiB 16.00KiB none none 1/0 --- 1/0 0.00B 0.00B none none --- 0/258 ^^^^^^^^^^^^^^^^^^^^ [CAUSE] The problem is in btrfs_qgroup_inherit(), we don't have good enough check to determine if the new relation would break the existing accounting. Unlike btrfs_add_qgroup_relation(), which has proper check to determine if we can do quick update without a rescan, in btrfs_qgroup_inherit() we can even assign a snapshot to multiple qgroups. [FIX] Fix it by manually marking qgroup inconsistent for snapshot inheritance. For subvolume creation, since all its extents are exclusively owned, we don't need to rescan. In theory, we should call relation check like quick_update_accounting() when doing qgroup inheritance and inform user about qgroup accounting inconsistency. But we don't have good mechanism to relay that back to the user in the snapshot creation context, thus we can only silently mark the qgroup inconsistent. Anyway, user shouldn't use qgroup inheritance during snapshot creation, and should add qgroup relationship after snapshot creation by 'btrfs qgroup assign', which has a much better UI to inform user about qgroup inconsistent and kick in rescan automatically. Reviewed-by: Josef Bacik Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/qgroup.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index cbd40826f5dc..c8ed4db73b84 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -2259,6 +2259,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, struct btrfs_root *quota_root; struct btrfs_qgroup *srcgroup; struct btrfs_qgroup *dstgroup; + bool need_rescan = false; u32 level_size = 0; u64 nums; @@ -2402,6 +2403,13 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, goto unlock; } ++i_qgroups; + + /* + * If we're doing a snapshot, and adding the snapshot to a new + * qgroup, the numbers are guaranteed to be incorrect. + */ + if (srcid) + need_rescan = true; } for (i = 0; i < inherit->num_ref_copies; ++i, i_qgroups += 2) { @@ -2421,6 +2429,9 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, dst->rfer = src->rfer - level_size; dst->rfer_cmpr = src->rfer_cmpr - level_size; + + /* Manually tweaking numbers certainly needs a rescan */ + need_rescan = true; } for (i = 0; i < inherit->num_excl_copies; ++i, i_qgroups += 2) { struct btrfs_qgroup *src; @@ -2439,6 +2450,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, dst->excl = src->excl + level_size; dst->excl_cmpr = src->excl_cmpr + level_size; + need_rescan = true; } unlock: @@ -2446,6 +2458,8 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, out: if (!committing) mutex_unlock(&fs_info->qgroup_ioctl_lock); + if (need_rescan) + fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT; return ret; } -- 2.25.1