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=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 1BB96C433E0 for ; Thu, 11 Mar 2021 03:06:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDFDF64FC6 for ; Thu, 11 Mar 2021 03:06:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229767AbhCKDGE (ORCPT ); Wed, 10 Mar 2021 22:06:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:45714 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229778AbhCKDF5 (ORCPT ); Wed, 10 Mar 2021 22:05:57 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6F1D964EDB; Thu, 11 Mar 2021 03:05:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615431957; bh=WG+ja7N7H8Y/QGkwfK6rVDuuSZO88XfisSFbrls4Mgg=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=BgXruYdrnm1cqSI6u/FS3hc/1VsqANNk5Oh14+YSWpIBQXOrmirACLWYDIiq91Yp2 6cXVZcvOZ+1igG7VlpwHEwd02kXRfl09+B+oe1k6fjrXXL9s8rFKQhubsDcKITYKsP 1SwZbFedIoYaumR71WTBXEJuARwxGnJPtjz75gQYme21nhAd8Bz9hf0VxqxnenZiL7 S/++Gb7dQmp+i+P11xhXaVmNv3l2DSP5W1ox5k2dQrmFJlqkzqgyFIUS+gNSQPGIEG IMNHBhxdvKziBPdE6KtP7WZ/atK8V0r3EUO96T+OY42cRZq85MHnQVsDdnJ418uCwY EaHYFMPcOwIyQ== Subject: [PATCH 03/11] xfs: don't reclaim dquots with incore reservations From: "Darrick J. Wong" To: djwong@kernel.org Cc: linux-xfs@vger.kernel.org Date: Wed, 10 Mar 2021 19:05:57 -0800 Message-ID: <161543195719.1947934.8218545606940173264.stgit@magnolia> In-Reply-To: <161543194009.1947934.9910987247994410125.stgit@magnolia> References: <161543194009.1947934.9910987247994410125.stgit@magnolia> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Darrick J. Wong If a dquot has an incore reservation that exceeds the ondisk count, it by definition has active incore state and must not be reclaimed. Up to this point every inode with an incore dquot reservation has always retained a reference to the dquot so it was never possible for xfs_qm_dquot_isolate to be called on a dquot with active state and zero refcount, but this will soon change. Deferred inode inactivation is about to reorganize how inodes are inactivated by shunting all that work to a background workqueue. In order to avoid deadlocks with the quotaoff inode scan and reduce overall memory requirements (since inodes can spend a lot of time waiting for inactivation), inactive inodes will drop their dquot references while they're waiting to be inactivated. However, inactive inodes can have delalloc extents in the data fork or any extents in the CoW fork. Either of these contribute to the dquot's incore reservation being larger than the resource count (i.e. they're the reason the dquot still has active incore state), so we cannot allow the dquot to be reclaimed. Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_qm.c | 29 ++++++++++++++++++++++++----- fs/xfs/xfs_qm.h | 17 +++++++++++++++++ 2 files changed, 41 insertions(+), 5 deletions(-) diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c index bfa4164990b1..b3ce04dec181 100644 --- a/fs/xfs/xfs_qm.c +++ b/fs/xfs/xfs_qm.c @@ -166,9 +166,14 @@ xfs_qm_dqpurge( /* * We move dquots to the freelist as soon as their reference count - * hits zero, so it really should be on the freelist here. + * hits zero, so it really should be on the freelist here. If we're + * running quotaoff, it's possible that we're purging a zero-refcount + * dquot with active incore reservation because there are inodes + * awaiting inactivation. Dquots in this state will not be on the LRU + * but it's quotaoff, so we don't care. */ - ASSERT(!list_empty(&dqp->q_lru)); + ASSERT(!(mp->m_qflags & xfs_quota_active_flag(xfs_dquot_type(dqp))) || + !list_empty(&dqp->q_lru)); list_lru_del(&qi->qi_lru, &dqp->q_lru); XFS_STATS_DEC(mp, xs_qm_dquot_unused); @@ -411,6 +416,15 @@ struct xfs_qm_isolate { struct list_head dispose; }; +static inline bool +xfs_dquot_has_incore_resv( + struct xfs_dquot *dqp) +{ + return dqp->q_blk.reserved > dqp->q_blk.count || + dqp->q_ino.reserved > dqp->q_ino.count || + dqp->q_rtb.reserved > dqp->q_rtb.count; +} + static enum lru_status xfs_qm_dquot_isolate( struct list_head *item, @@ -427,10 +441,15 @@ xfs_qm_dquot_isolate( goto out_miss_busy; /* - * This dquot has acquired a reference in the meantime remove it from - * the freelist and try again. + * Either this dquot has incore reservations or it has acquired a + * reference. Remove it from the freelist and try again. + * + * Inodes tagged for inactivation drop their dquot references to avoid + * deadlocks with quotaoff. If these inodes have delalloc reservations + * in the data fork or any extents in the CoW fork, these contribute + * to the dquot's incore block reservation exceeding the count. */ - if (dqp->q_nrefs) { + if (xfs_dquot_has_incore_resv(dqp) || dqp->q_nrefs) { xfs_dqunlock(dqp); XFS_STATS_INC(dqp->q_mount, xs_qm_dqwants); diff --git a/fs/xfs/xfs_qm.h b/fs/xfs/xfs_qm.h index e3dabab44097..78f90935e91e 100644 --- a/fs/xfs/xfs_qm.h +++ b/fs/xfs/xfs_qm.h @@ -105,6 +105,23 @@ xfs_quota_inode(struct xfs_mount *mp, xfs_dqtype_t type) return NULL; } +static inline unsigned int +xfs_quota_active_flag( + xfs_dqtype_t type) +{ + switch (type) { + case XFS_DQTYPE_USER: + return XFS_UQUOTA_ACTIVE; + case XFS_DQTYPE_GROUP: + return XFS_GQUOTA_ACTIVE; + case XFS_DQTYPE_PROJ: + return XFS_PQUOTA_ACTIVE; + default: + ASSERT(0); + } + return 0; +} + extern void xfs_trans_mod_dquot(struct xfs_trans *tp, struct xfs_dquot *dqp, uint field, int64_t delta); extern void xfs_trans_dqjoin(struct xfs_trans *, struct xfs_dquot *);