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 80FABC433E0 for ; Thu, 21 Jan 2021 16:51:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 313C723A3C for ; Thu, 21 Jan 2021 16:51:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387822AbhAUQuU (ORCPT ); Thu, 21 Jan 2021 11:50:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:36316 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387939AbhAUQuP (ORCPT ); Thu, 21 Jan 2021 11:50:15 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7516C23A33; Thu, 21 Jan 2021 16:49:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611247774; bh=X4nROZ75f30MW+uojAR3g+0n4YsXa28ligOVBC33oeI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sWBilSRSW0yv4fZaGViAyQvrKgDKGkjPaUcyVntMhtxko79wOPOho4RfOCQ/UHd6a UAO3OHdCgLzGm6qnvLGtDGSqQYRXGS9VkEyFsR0wogxtnm59GJb2R9bHEd0fqh6Qiv PT8YM3HF3wYtdLnAgIzTcGIeievCiUraPIHdZGCzFLnQlggig42+VA+Xx89FFUMcXc V4DyR/xF9rIg8vGlfWst4ytmGGCiGx/uetMNe8EW3llau4tm4P8uxGX7CLp1UYVAZF g1hCiZ7oLLqcGjyw9dYuAi7HOsUN+361UaDqGXNNK4oEdyd+aPJFnhbzLXc3IKlz5k es7eKNnnw9b4Q== Date: Thu, 21 Jan 2021 08:49:33 -0800 From: "Darrick J. Wong" To: Bill O'Donnell Cc: Brian Foster , linux-xfs@vger.kernel.org Subject: Re: [PATCH 1/9] xfs: sync lazy sb accounting on quiesce of read-only mounts Message-ID: <20210121164933.GA1282159@magnolia> References: <20210106174127.805660-1-bfoster@redhat.com> <20210106174127.805660-2-bfoster@redhat.com> <20210121150827.GA1118971@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210121150827.GA1118971@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Thu, Jan 21, 2021 at 09:08:27AM -0600, Bill O'Donnell wrote: > On Wed, Jan 06, 2021 at 12:41:19PM -0500, Brian Foster wrote: > > xfs_log_sbcount() syncs the superblock specifically to accumulate > > the in-core percpu superblock counters and commit them to disk. This > > is required to maintain filesystem consistency across quiesce > > (freeze, read-only mount/remount) or unmount when lazy superblock > > accounting is enabled because individual transactions do not update > > the superblock directly. > > > > This mechanism works as expected for writable mounts, but > > xfs_log_sbcount() skips the update for read-only mounts. Read-only > > mounts otherwise still allow log recovery and write out an unmount > > record during log quiesce. If a read-only mount performs log > > recovery, it can modify the in-core superblock counters and write an > > unmount record when the filesystem unmounts without ever syncing the > > in-core counters. This leaves the filesystem with a clean log but in > > an inconsistent state with regard to lazy sb counters. > > > > Update xfs_log_sbcount() to use the same logic > > xfs_log_unmount_write() uses to determine when to write an unmount > > record. We can drop the freeze state check because the update is > > already allowed during the freezing process and no context calls > > this function on an already frozen fs. This ensures that lazy > > accounting is always synced before the log is cleaned. Refactor this > > logic into a new helper to distinguish between a writable filesystem > > and a writable log. Specifically, the log is writable unless the > > filesystem is mounted with the norecovery mount option, the > > underlying log device is read-only, or the filesystem is shutdown. > > > > Signed-off-by: Brian Foster > > Reviewed-by: Gao Xiang > > works for me. > Reviewed-by: Bill O'Donnell Does this also apply to the v3 series that Brian just sent? --D > > > --- > > fs/xfs/xfs_log.c | 28 ++++++++++++++++++++-------- > > fs/xfs/xfs_log.h | 1 + > > fs/xfs/xfs_mount.c | 3 +-- > > 3 files changed, 22 insertions(+), 10 deletions(-) > > > > diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c > > index fa2d05e65ff1..b445e63cbc3c 100644 > > --- a/fs/xfs/xfs_log.c > > +++ b/fs/xfs/xfs_log.c > > @@ -347,6 +347,25 @@ xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type) > > tic->t_res_num++; > > } > > > > +bool > > +xfs_log_writable( > > + struct xfs_mount *mp) > > +{ > > + /* > > + * Never write to the log on norecovery mounts, if the block device is > > + * read-only, or if the filesystem is shutdown. Read-only mounts still > > + * allow internal writes for log recovery and unmount purposes, so don't > > + * restrict that case here. > > + */ > > + if (mp->m_flags & XFS_MOUNT_NORECOVERY) > > + return false; > > + if (xfs_readonly_buftarg(mp->m_log->l_targ)) > > + return false; > > + if (XFS_FORCED_SHUTDOWN(mp)) > > + return false; > > + return true; > > +} > > + > > /* > > * Replenish the byte reservation required by moving the grant write head. > > */ > > @@ -886,15 +905,8 @@ xfs_log_unmount_write( > > { > > struct xlog *log = mp->m_log; > > > > - /* > > - * Don't write out unmount record on norecovery mounts or ro devices. > > - * Or, if we are doing a forced umount (typically because of IO errors). > > - */ > > - if (mp->m_flags & XFS_MOUNT_NORECOVERY || > > - xfs_readonly_buftarg(log->l_targ)) { > > - ASSERT(mp->m_flags & XFS_MOUNT_RDONLY); > > + if (!xfs_log_writable(mp)) > > return; > > - } > > > > xfs_log_force(mp, XFS_LOG_SYNC); > > > > diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h > > index 58c3fcbec94a..98c913da7587 100644 > > --- a/fs/xfs/xfs_log.h > > +++ b/fs/xfs/xfs_log.h > > @@ -127,6 +127,7 @@ int xfs_log_reserve(struct xfs_mount *mp, > > int xfs_log_regrant(struct xfs_mount *mp, struct xlog_ticket *tic); > > void xfs_log_unmount(struct xfs_mount *mp); > > int xfs_log_force_umount(struct xfs_mount *mp, int logerror); > > +bool xfs_log_writable(struct xfs_mount *mp); > > > > struct xlog_ticket *xfs_log_ticket_get(struct xlog_ticket *ticket); > > void xfs_log_ticket_put(struct xlog_ticket *ticket); > > diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c > > index 7110507a2b6b..a62b8a574409 100644 > > --- a/fs/xfs/xfs_mount.c > > +++ b/fs/xfs/xfs_mount.c > > @@ -1176,8 +1176,7 @@ xfs_fs_writable( > > int > > xfs_log_sbcount(xfs_mount_t *mp) > > { > > - /* allow this to proceed during the freeze sequence... */ > > - if (!xfs_fs_writable(mp, SB_FREEZE_COMPLETE)) > > + if (!xfs_log_writable(mp)) > > return 0; > > > > /* > > -- > > 2.26.2 > > >