From patchwork Thu Feb 27 13:43:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brian Foster X-Patchwork-Id: 11408769 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A510914D5 for ; Thu, 27 Feb 2020 14:48:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 79A4924691 for ; Thu, 27 Feb 2020 14:48:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WPleX09+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729625AbgB0OsL (ORCPT ); Thu, 27 Feb 2020 09:48:11 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:56947 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729959AbgB0Nn1 (ORCPT ); Thu, 27 Feb 2020 08:43:27 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582811006; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qcVU/Ad5k6xmcd73Mj8LD9ajLQszhmypF3+9/C+QKkc=; b=WPleX09+xBQd+PpM5ag+EnJ4j8kjTQHMdJsF2cz3WMtBYXlMD8CF4kwPKqgf9zSoGLyQYv ud1dkATE9TNyl3wyFh0ye/Ag9HUue21MV8Bl6tCQPM0yklN3Sy4559woc9OU2Z5KyyqlE8 nXTBGy379ruRcGw0aMAFFfttBlKkVbM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-363-kWg0Li0CM8yLDhA-GojiJw-1; Thu, 27 Feb 2020 08:43:24 -0500 X-MC-Unique: kWg0Li0CM8yLDhA-GojiJw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EC1FE1084437 for ; Thu, 27 Feb 2020 13:43:23 +0000 (UTC) Received: from bfoster.bos.redhat.com (dhcp-41-2.bos.redhat.com [10.18.41.2]) by smtp.corp.redhat.com (Postfix) with ESMTP id B53FC5DA7E for ; Thu, 27 Feb 2020 13:43:23 +0000 (UTC) From: Brian Foster To: linux-xfs@vger.kernel.org Subject: [RFC v5 PATCH 6/9] xfs: automatically relog the quotaoff start intent Date: Thu, 27 Feb 2020 08:43:18 -0500 Message-Id: <20200227134321.7238-7-bfoster@redhat.com> In-Reply-To: <20200227134321.7238-1-bfoster@redhat.com> References: <20200227134321.7238-1-bfoster@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org The quotaoff operation has a rare but longstanding deadlock vector in terms of how the operation is logged. A quotaoff start intent is logged (synchronously) at the onset to ensure recovery can handle the operation if interrupted before in-core changes are made. This quotaoff intent pins the log tail while the quotaoff sequence scans and purges dquots from all in-core inodes. While this operation generally doesn't generate much log traffic on its own, it can be time consuming. If unrelated, concurrent filesystem activity consumes remaining log space before quotaoff is able to acquire log reservation for the quotaoff end intent, the filesystem locks up indefinitely. quotaoff cannot allocate the end intent before the scan because the latter can result in transaction allocation itself in certain indirect cases (releasing an inode, for example). Further, rolling the original transaction is difficult because the scanning work occurs multiple layers down where caller context is lost and not much information is available to determine how often to roll the transaction. To address this problem, enable automatic relogging of the quotaoff start intent. This automatically relogs the intent whenever AIL pushing finds the item at the tail of the log. When quotaoff completes, wait for relogging to complete as the end intent expects to be able to permanently remove the start intent from the log subsystem. This ensures that the log tail is kept moving during a particularly long quotaoff operation and avoids the log reservation deadlock. Signed-off-by: Brian Foster --- fs/xfs/libxfs/xfs_trans_resv.c | 3 ++- fs/xfs/xfs_dquot_item.c | 7 +++++++ fs/xfs/xfs_qm_syscalls.c | 12 +++++++++++- 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c index 1f5c9e6e1afc..f49b20c9ca33 100644 --- a/fs/xfs/libxfs/xfs_trans_resv.c +++ b/fs/xfs/libxfs/xfs_trans_resv.c @@ -935,7 +935,8 @@ xfs_trans_resv_calc( resp->tr_qm_setqlim.tr_logcount = XFS_DEFAULT_LOG_COUNT; resp->tr_qm_quotaoff.tr_logres = xfs_calc_qm_quotaoff_reservation(mp); - resp->tr_qm_quotaoff.tr_logcount = XFS_DEFAULT_LOG_COUNT; + resp->tr_qm_quotaoff.tr_logcount = XFS_DEFAULT_PERM_LOG_COUNT; + resp->tr_qm_quotaoff.tr_logflags |= XFS_TRANS_PERM_LOG_RES; resp->tr_qm_equotaoff.tr_logres = xfs_calc_qm_quotaoff_end_reservation(); diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c index d60647d7197b..ea5123678466 100644 --- a/fs/xfs/xfs_dquot_item.c +++ b/fs/xfs/xfs_dquot_item.c @@ -297,6 +297,13 @@ xfs_qm_qoff_logitem_push( struct xfs_log_item *lip, struct list_head *buffer_list) { + struct xfs_log_item *mlip = xfs_ail_min(lip->li_ailp); + + if (test_bit(XFS_LI_RELOG, &lip->li_flags) && + !test_bit(XFS_LI_RELOGGED, &lip->li_flags) && + !XFS_LSN_CMP(lip->li_lsn, mlip->li_lsn)) + return XFS_ITEM_RELOG; + return XFS_ITEM_LOCKED; } diff --git a/fs/xfs/xfs_qm_syscalls.c b/fs/xfs/xfs_qm_syscalls.c index 1ea82764bf89..7b48d34da0f4 100644 --- a/fs/xfs/xfs_qm_syscalls.c +++ b/fs/xfs/xfs_qm_syscalls.c @@ -18,6 +18,7 @@ #include "xfs_quota.h" #include "xfs_qm.h" #include "xfs_icache.h" +#include "xfs_trans_priv.h" STATIC int xfs_qm_log_quotaoff( @@ -31,12 +32,14 @@ xfs_qm_log_quotaoff( *qoffstartp = NULL; - error = xfs_trans_alloc(mp, &M_RES(mp)->tr_qm_quotaoff, 0, 0, 0, &tp); + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_qm_quotaoff, 0, 0, + XFS_TRANS_RELOG, &tp); if (error) goto out; qoffi = xfs_trans_get_qoff_item(tp, NULL, flags & XFS_ALL_QUOTA_ACCT); xfs_trans_log_quotaoff_item(tp, qoffi); + xfs_trans_relog_item(&qoffi->qql_item); spin_lock(&mp->m_sb_lock); mp->m_sb.sb_qflags = (mp->m_qflags & ~(flags)) & XFS_MOUNT_QUOTA_ALL; @@ -69,6 +72,13 @@ xfs_qm_log_quotaoff_end( int error; struct xfs_qoff_logitem *qoffi; + /* + * startqoff must be in the AIL and not the CIL when the end intent + * commits to ensure it is not readded to the AIL out of order. Wait on + * relog activity to drain to isolate startqoff to the AIL. + */ + xfs_trans_relog_item_cancel(&startqoff->qql_item, true); + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_qm_equotaoff, 0, 0, 0, &tp); if (error) return error;