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 86A86C433F5 for ; Wed, 9 Mar 2022 23:36:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232196AbiCIXh4 (ORCPT ); Wed, 9 Mar 2022 18:37:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238895AbiCIXhs (ORCPT ); Wed, 9 Mar 2022 18:37:48 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A458E106C8D for ; Wed, 9 Mar 2022 15:36:47 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 31112B8216F for ; Wed, 9 Mar 2022 23:36:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFFB6C340EF; Wed, 9 Mar 2022 23:36:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646869004; bh=BzB8wTd9VqTX/2R6FhQMSmGkVvwqXQoViRCNHK0la+I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hOCv1k2lThGQmIGdBouORjCpZ16ZtoKAVILV6Z/GQOkfyoo2kYdzJAd79WrMOlgJj NoZRjQwfsHfJR2HC+f8xMk7ZRyPMkoNCkVW+f99p8L1BJQ6fuyMY+o2slId74xoY+/ 8rDBCqqM8XzKwGiTy1tIYXphnu16LkpEFMmq7smnP/10X+03fDVqf/ISyt2Q0C9TqX A/rsVXE7iYJO5DnqTxxwDk2zBZiYMDsZBPS90dXxJb7streX7dokhpVr7VBWgXXqMg oXspLuvAUl++zRuIU3rHf7Who7ojm9x3tJgTTl9dAfwi1Mw/VhmcHsGUDxn33/8pUx h7apGiDpZ2BUA== Date: Wed, 9 Mar 2022 15:36:44 -0800 From: "Darrick J. Wong" To: Dave Chinner Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH 2/2] xfs: reserve quota for target dir expansion when renaming files Message-ID: <20220309233644.GF8224@magnolia> References: <164685374120.495923.2523387358442198692.stgit@magnolia> <164685375248.495923.9228795379646460264.stgit@magnolia> <20220309220553.GI661808@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220309220553.GI661808@dread.disaster.area> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Thu, Mar 10, 2022 at 09:05:53AM +1100, Dave Chinner wrote: > On Wed, Mar 09, 2022 at 11:22:32AM -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. > > Yeah, and this makes it even more tricky - the retry jumps back > across the RENAME_EXCHANGE callout/exit from xfs_rename. At some > point we need to clean up the spaghetti that rename has become. Heh. I did that as a cleanup to the directory code ahead of the metadata directory tree patchset. > > Signed-off-by: Darrick J. Wong > > --- > > fs/xfs/xfs_inode.c | 37 ++++++++++++++++++++++++++++++++++++- > > 1 file changed, 36 insertions(+), 1 deletion(-) > > > > > > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > > index a131bbfe74e4..8ff67b7aad53 100644 > > --- a/fs/xfs/xfs_inode.c > > +++ b/fs/xfs/xfs_inode.c > > @@ -3095,7 +3095,8 @@ xfs_rename( > > bool new_parent = (src_dp != target_dp); > > bool src_is_directory = S_ISDIR(VFS_I(src_ip)->i_mode); > > int spaceres; > > - int error; > > + bool retried = false; > > + int error, space_error; > > > > trace_xfs_rename(src_dp, target_dp, src_name, target_name); > > > > @@ -3119,9 +3120,12 @@ xfs_rename( > > xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip, wip, > > inodes, &num_inodes); > > > > +retry: > > + space_error = 0; > > spaceres = XFS_RENAME_SPACE_RES(mp, target_name->len); > > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_rename, spaceres, 0, 0, &tp); > > if (error == -ENOSPC) { > > + space_error = error; > > nospace_error. Fixed. > > spaceres = 0; > > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_rename, 0, 0, 0, > > &tp); > > @@ -3175,6 +3179,31 @@ xfs_rename( > > target_dp, target_name, target_ip, > > spaceres); > > > > + /* > > + * Try to reserve quota to handle an expansion of the target directory. > > + * We'll allow the rename to continue in reservationless mode if we hit > > + * a space usage constraint. If we trigger reservationless mode, save > > + * the errno if there isn't any free space in the target directory. > > + */ > > + if (spaceres != 0) { > > + error = xfs_trans_reserve_quota_nblks(tp, target_dp, spaceres, > > + 0, false); > > + if (error == -EDQUOT || error == -ENOSPC) { > > + if (!retried) { > > + xfs_trans_cancel(tp); > > + xfs_blockgc_free_quota(target_dp, 0); > > + retried = true; > > + goto retry; > > + } > > + > > + space_error = error; > > + spaceres = 0; > > + error = 0; > > + } > > + if (error) > > + goto out_trans_cancel; > > + } > > + > > /* > > * Check for expected errors before we dirty the transaction > > * so we can return an error without a transaction abort. > > @@ -3215,6 +3244,8 @@ xfs_rename( > > */ > > if (!spaceres) { > > error = xfs_dir_canenter(tp, target_dp, target_name); > > + if (error == -ENOSPC && space_error) > > + error = space_error; > > And move this error transformation to out_trans_cancel: so it only > has to be coded once. > > Other than that, it's about as clean as rename allows it to be right > now. Fixed. --D > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com