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 7216BC433EF for ; Thu, 10 Mar 2022 22:28:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245626AbiCJW3l (ORCPT ); Thu, 10 Mar 2022 17:29:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233618AbiCJW3l (ORCPT ); Thu, 10 Mar 2022 17:29:41 -0500 Received: from mail105.syd.optusnet.com.au (mail105.syd.optusnet.com.au [211.29.132.249]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9E736517FC for ; Thu, 10 Mar 2022 14:28:38 -0800 (PST) Received: from dread.disaster.area (pa49-186-150-27.pa.vic.optusnet.com.au [49.186.150.27]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 3D07910E3DF3; Fri, 11 Mar 2022 09:28:38 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1nSRGv-003x5P-NM; Fri, 11 Mar 2022 09:28:37 +1100 Date: Fri, 11 Mar 2022 09:28:37 +1100 From: Dave Chinner To: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH 2/2] xfs: reserve quota for target dir expansion when renaming files Message-ID: <20220310222837.GH3927073@dread.disaster.area> References: <164694920783.1119636.13401244964062260779.stgit@magnolia> <164694921916.1119636.2957657161513150271.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <164694921916.1119636.2957657161513150271.stgit@magnolia> X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.4 cv=e9dl9Yl/ c=1 sm=1 tr=0 ts=622a7b96 a=sPqof0Mm7fxWrhYUF33ZaQ==:117 a=sPqof0Mm7fxWrhYUF33ZaQ==:17 a=kj9zAlcOel0A:10 a=o8Y5sQTvuykA:10 a=VwQbUJbxAAAA:8 a=20KFwNOVAAAA:8 a=7-415B0cAAAA:8 a=emE5smVbIvwbOYP1doMA:9 a=CjuIK1q_8ugA:10 a=AjGcO6oz07-iQ99wixmX:22 a=biEYGPWJfzWAr4FL6Ov7:22 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Thu, Mar 10, 2022 at 01:53:39PM -0800, Darrick J. Wong wrote: > From: Darrick J. Wong > > XFS does not reserve quota for directory expansion when renaming > children into a directory. This means that we don't reject the > expansion with EDQUOT when we're at or near a hard limit, which means > that unprivileged userspace can use rename() to exceed quota. > > Rename operations don't always expand the target directory, and we allow > a rename to proceed with no space reservation if we don't need to add a > block to the target directory to handle the addition. Moreover, the > unlink operation on the source directory generally does not expand the > directory (you'd have to free a block and then cause a btree split) and > it's probably of little consequence to leave the corner case that > renaming a file out of a directory can increase its size. > > As with link and unlink, there is a further bug in that we do not > trigger the blockgc workers to try to clear space when we're out of > quota. > > Because rename is its own special tricky animal, we'll patch xfs_rename > directly to reserve quota to the rename transaction. We'll leave > cleaning up the rest of xfs_rename for the metadata directory tree > patchset. > > Signed-off-by: Darrick J. Wong > --- > fs/xfs/xfs_inode.c | 33 ++++++++++++++++++++++++++++++++- > 1 file changed, 32 insertions(+), 1 deletion(-) LGTM. Reviewed-by: Dave Chinner -- Dave Chinner david@fromorbit.com