From: Dave Chinner <david@fromorbit.com>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 1/2] xfs: only clear log incompat flags at clean unmount
Date: Mon, 8 Apr 2024 08:48:01 +1000 [thread overview]
Message-ID: <ZhMioUHDoF9QmI/D@dread.disaster.area> (raw)
In-Reply-To: <171150379743.3216346.12598577809015628376.stgit@frogsfrogsfrogs>
On Tue, Mar 26, 2024 at 06:50:44PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> While reviewing the online fsck patchset, someone spied the
> xfs_swapext_can_use_without_log_assistance function and wondered why we
> go through this inverted-bitmask dance to avoid setting the
> XFS_SB_FEAT_INCOMPAT_LOG_SWAPEXT feature.
>
> (The same principles apply to the logged extended attribute update
> feature bit in the since-merged LARP series.)
>
> The reason for this dance is that xfs_add_incompat_log_feature is an
> expensive operation -- it forces the log, pushes the AIL, and then if
> nobody's beaten us to it, sets the feature bit and issues a synchronous
> write of the primary superblock. That could be a one-time cost
> amortized over the life of the filesystem, but the log quiesce and cover
> operations call xfs_clear_incompat_log_features to remove feature bits
> opportunistically. On a moderately loaded filesystem this leads to us
> cycling those bits on and off over and over, which hurts performance.
>
> Why do we clear the log incompat bits? Back in ~2020 I think Dave and I
> had a conversation on IRC[2] about what the log incompat bits represent.
> IIRC in that conversation we decided that the log incompat bits protect
> unrecovered log items so that old kernels won't try to recover them and
> barf. Since a clean log has no protected log items, we could clear the
> bits at cover/quiesce time.
>
> As Dave Chinner pointed out in the thread, clearing log incompat bits at
> unmount time has positive effects for golden root disk image generator
> setups, since the generator could be running a newer kernel than what
> gets written to the golden image -- if there are log incompat fields set
> in the golden image that was generated by a newer kernel/OS image
> builder then the provisioning host cannot mount the filesystem even
> though the log is clean and recovery is unnecessary to mount the
> filesystem.
>
> Given that it's expensive to set log incompat bits, we really only want
> to do that once per bit per mount. Therefore, I propose that we only
> clear log incompat bits as part of writing a clean unmount record. Do
> this by adding an operational state flag to the xfs mount that guards
> whether or not the feature bit clearing can actually take place.
>
> This eliminates the l_incompat_users rwsem that we use to protect a log
> cleaning operation from clearing a feature bit that a frontend thread is
> trying to set -- this lock adds another way to fail w.r.t. locking. For
> the swapext series, I shard that into multiple locks just to work around
> the lockdep complaints, and that's fugly.
>
> Link: https://lore.kernel.org/linux-xfs/20240131230043.GA6180@frogsfrogsfrogs/
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
> .../filesystems/xfs/xfs-online-fsck-design.rst | 3 -
> fs/xfs/xfs_log.c | 28 -------------
> fs/xfs/xfs_log.h | 2 -
> fs/xfs/xfs_log_priv.h | 3 -
> fs/xfs/xfs_log_recover.c | 15 -------
> fs/xfs/xfs_mount.c | 8 +++-
> fs/xfs/xfs_mount.h | 6 ++-
> fs/xfs/xfs_xattr.c | 42 +++-----------------
> 8 files changed, 19 insertions(+), 88 deletions(-)
Looks fine.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2024-04-07 22:48 UTC|newest]
Thread overview: 146+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-27 1:40 [PATCHBOMB v30] xfs: online fsck patches for 6.10 Darrick J. Wong
2024-03-27 1:46 ` [PATCHSET 01/15] xfs: bug fixes for 6.9 Darrick J. Wong
2024-03-27 1:50 ` [PATCH 1/1] xfs: fix potential AGI <-> ILOCK ABBA deadlock in xrep_dinode_findmode_walk_directory Darrick J. Wong
2024-03-27 16:56 ` Christoph Hellwig
2024-03-29 18:38 ` Darrick J. Wong
2024-04-03 5:18 ` [PATCHSET] xfs: bug fixes for 6.9 Darrick J. Wong
2024-04-03 5:18 ` [PATCH 1/3] xfs: pass xfs_buf lookup flags to xfs_*read_agi Darrick J. Wong
2024-04-05 14:53 ` Christoph Hellwig
2024-04-03 5:18 ` [PATCH 2/3] xfs: fix an AGI lock acquisition ordering problem in xrep_dinode_findmode Darrick J. Wong
2024-04-05 14:54 ` Christoph Hellwig
2024-04-05 16:52 ` Christoph Hellwig
2024-04-07 22:34 ` Dave Chinner
2024-04-09 22:51 ` Darrick J. Wong
2024-04-03 5:18 ` [PATCH 3/3] xfs: fix potential AGI <-> ILOCK ABBA deadlock in xrep_dinode_findmode_walk_directory Darrick J. Wong
2024-04-05 3:27 ` [PATCH 4/3] xfs: fix error bailout in xrep_abt_build_new_trees Darrick J. Wong
2024-04-05 5:17 ` Christoph Hellwig
2024-03-27 1:46 ` [PATCHSET v30.1 02/15] xfs: improve log incompat feature handling Darrick J. Wong
2024-03-27 1:50 ` [PATCH 1/2] xfs: only clear log incompat flags at clean unmount Darrick J. Wong
2024-04-07 22:48 ` Dave Chinner [this message]
2024-03-27 1:51 ` [PATCH 2/2] xfs: only add log incompat features with explicit permission Darrick J. Wong
2024-04-07 23:00 ` Dave Chinner
2024-04-09 22:53 ` Darrick J. Wong
2024-03-27 1:47 ` [PATCHSET v30.1 03/15] xfs: refactorings for atomic file content exchanges Darrick J. Wong
2024-03-27 1:51 ` [PATCH 1/7] xfs: move inode lease breaking functions to xfs_inode.c Darrick J. Wong
2024-03-27 1:51 ` [PATCH 2/7] xfs: move xfs_iops.c declarations out of xfs_inode.h Darrick J. Wong
2024-03-27 1:51 ` [PATCH 3/7] xfs: declare xfs_file.c symbols in xfs_file.h Darrick J. Wong
2024-03-27 1:52 ` [PATCH 4/7] xfs: create a new helper to return a file's allocation unit Darrick J. Wong
2024-03-27 1:52 ` [PATCH 5/7] xfs: hoist multi-fsb allocation unit detection to a helper Darrick J. Wong
2024-03-27 11:05 ` Christoph Hellwig
2024-04-07 23:07 ` Dave Chinner
2024-04-09 21:09 ` Darrick J. Wong
2024-03-27 1:52 ` [PATCH 6/7] xfs: refactor non-power-of-two alignment checks Darrick J. Wong
2024-03-27 1:52 ` [PATCH 7/7] xfs: constify xfs_bmap_is_written_extent Darrick J. Wong
2024-03-27 1:47 ` [PATCHSET v30.1 04/15] xfs: atomic file content exchanges Darrick J. Wong
2024-03-27 1:53 ` [PATCH 01/15] vfs: export remap and write check helpers Darrick J. Wong
2024-03-27 11:07 ` Christoph Hellwig
2024-03-29 19:45 ` Darrick J. Wong
2024-03-27 1:53 ` [PATCH 02/15] xfs: introduce new file range exchange ioctl Darrick J. Wong
2024-03-27 11:12 ` Christoph Hellwig
2024-03-27 1:53 ` [PATCH 03/15] xfs: create a log incompat flag for atomic file mapping exchanges Darrick J. Wong
2024-04-07 23:17 ` Dave Chinner
2024-04-09 21:12 ` Darrick J. Wong
2024-03-27 1:53 ` [PATCH 04/15] xfs: introduce a file mapping exchange log intent item Darrick J. Wong
2024-04-07 23:51 ` Dave Chinner
2024-04-09 1:18 ` Darrick J. Wong
2024-04-09 3:06 ` Darrick J. Wong
2024-03-27 1:54 ` [PATCH 05/15] xfs: create deferred log items for file mapping exchanges Darrick J. Wong
2024-03-27 1:54 ` [PATCH 06/15] xfs: bind together the front and back ends of the file range exchange code Darrick J. Wong
2024-04-08 0:05 ` Dave Chinner
2024-03-27 1:54 ` [PATCH 07/15] xfs: add error injection to test file mapping exchange recovery Darrick J. Wong
2024-03-27 1:54 ` [PATCH 08/15] xfs: condense extended attributes after a mapping exchange operation Darrick J. Wong
2024-03-27 1:55 ` [PATCH 09/15] xfs: condense directories " Darrick J. Wong
2024-03-27 1:55 ` [PATCH 10/15] xfs: condense symbolic links " Darrick J. Wong
2024-03-27 1:55 ` [PATCH 11/15] xfs: make file range exchange support realtime files Darrick J. Wong
2024-03-27 1:55 ` [PATCH 12/15] xfs: support non-power-of-two rtextsize with exchange-range Darrick J. Wong
2024-03-27 1:56 ` [PATCH 13/15] docs: update swapext -> exchmaps language Darrick J. Wong
2024-03-27 1:56 ` [PATCH 14/15] xfs: introduce new file range commit ioctls Darrick J. Wong
2024-03-27 11:06 ` Christoph Hellwig
2024-03-29 19:45 ` Darrick J. Wong
2024-03-27 1:56 ` [PATCH 15/15] xfs: enable logged file mapping exchange feature Darrick J. Wong
2024-03-27 1:47 ` [PATCHSET v30.1 05/15] xfs: create temporary files for online repair Darrick J. Wong
2024-03-27 1:57 ` [PATCH 1/4] xfs: hide private inodes from bulkstat and handle functions Darrick J. Wong
2024-03-27 11:12 ` Christoph Hellwig
2024-03-27 1:57 ` [PATCH 2/4] xfs: create temporary files and directories for online repair Darrick J. Wong
2024-03-27 1:57 ` [PATCH 3/4] xfs: refactor live buffer invalidation for repairs Darrick J. Wong
2024-03-27 1:57 ` [PATCH 4/4] xfs: add the ability to reap entire inode forks Darrick J. Wong
2024-03-27 1:47 ` [PATCHSET v30.1 06/15] xfs: online repair of realtime summaries Darrick J. Wong
2024-03-27 1:58 ` [PATCH 1/3] xfs: support preallocating and copying content into temporary files Darrick J. Wong
2024-03-27 1:58 ` [PATCH 2/3] xfs: teach the tempfile to set up atomic file content exchanges Darrick J. Wong
2024-03-27 1:58 ` [PATCH 3/3] xfs: online repair of realtime summaries Darrick J. Wong
2024-03-27 1:48 ` [PATCHSET v30.1 07/15] xfs: set and validate dir/attr block owners Darrick J. Wong
2024-03-27 1:58 ` [PATCH 01/10] xfs: add an explicit owner field to xfs_da_args Darrick J. Wong
2024-03-27 1:59 ` [PATCH 02/10] xfs: use the xfs_da_args owner field to set new dir/attr block owner Darrick J. Wong
2024-03-27 1:59 ` [PATCH 03/10] xfs: reduce indenting in xfs_attr_node_list Darrick J. Wong
2024-03-27 11:13 ` Christoph Hellwig
2024-03-28 17:39 ` Darrick J. Wong
2024-03-27 1:59 ` [PATCH 04/10] xfs: validate attr leaf buffer owners Darrick J. Wong
2024-03-27 1:59 ` [PATCH 05/10] xfs: validate attr remote value " Darrick J. Wong
2024-03-27 2:00 ` [PATCH 06/10] xfs: validate dabtree node " Darrick J. Wong
2024-03-27 2:00 ` [PATCH 07/10] xfs: validate directory leaf " Darrick J. Wong
2024-03-27 2:00 ` [PATCH 08/10] xfs: validate explicit directory data " Darrick J. Wong
2024-03-27 2:00 ` [PATCH 09/10] xfs: validate explicit directory block " Darrick J. Wong
2024-03-27 2:01 ` [PATCH 10/10] xfs: validate explicit directory free block owners Darrick J. Wong
2024-03-27 1:48 ` [PATCHSET v30.1 08/15] xfs: online repair of extended attributes Darrick J. Wong
2024-03-27 2:01 ` [PATCH 1/7] xfs: enable discarding of folios backing an xfile Darrick J. Wong
2024-03-27 2:01 ` [PATCH 2/7] xfs: create a blob array data structure Darrick J. Wong
2024-03-27 2:01 ` [PATCH 3/7] xfs: use atomic extent swapping to fix user file fork data Darrick J. Wong
2024-03-27 2:02 ` [PATCH 4/7] xfs: repair extended attributes Darrick J. Wong
2024-03-27 2:02 ` [PATCH 5/7] xfs: scrub should set preen if attr leaf has holes Darrick J. Wong
2024-03-27 2:02 ` [PATCH 6/7] xfs: flag empty xattr leaf blocks for optimization Darrick J. Wong
2024-03-27 2:03 ` [PATCH 7/7] xfs: create an xattr iteration function for scrub Darrick J. Wong
2024-03-27 11:15 ` Christoph Hellwig
2024-03-27 1:48 ` [PATCHSET v30.1 09/15] xfs: online repair of inode unlinked state Darrick J. Wong
2024-03-27 2:03 ` [PATCH 1/2] xfs: ensure unlinked list state is consistent with nlink during scrub Darrick J. Wong
2024-03-27 2:03 ` [PATCH 2/2] xfs: update the unlinked list when repairing link counts Darrick J. Wong
2024-03-27 1:48 ` [PATCHSET v30.1 10/15] xfs: online repair of directories Darrick J. Wong
2024-03-27 2:03 ` [PATCH 1/5] xfs: inactivate directory data blocks Darrick J. Wong
2024-03-27 2:04 ` [PATCH 2/5] xfs: online repair of directories Darrick J. Wong
2024-03-27 2:04 ` [PATCH 3/5] xfs: scan the filesystem to repair a directory dotdot entry Darrick J. Wong
2024-03-27 2:04 ` [PATCH 4/5] xfs: online repair of parent pointers Darrick J. Wong
2024-03-27 2:04 ` [PATCH 5/5] xfs: ask the dentry cache if it knows the parent of a directory Darrick J. Wong
2024-03-27 11:16 ` Christoph Hellwig
2024-03-29 19:52 ` Darrick J. Wong
2024-04-03 5:03 ` [PATCH v30.2 " Darrick J. Wong
2024-04-03 11:43 ` Christoph Hellwig
2024-03-27 1:49 ` [PATCHSET v30.1 11/15] xfs: move orphan files to lost and found Darrick J. Wong
2024-03-27 2:05 ` [PATCH 1/3] xfs: move orphan files to the orphanage Darrick J. Wong
2024-03-27 2:05 ` [PATCH 2/3] xfs: move files to orphanage instead of letting nlinks drop to zero Darrick J. Wong
2024-03-27 2:05 ` [PATCH 3/3] xfs: ensure dentry consistency when the orphanage adopts a file Darrick J. Wong
2024-03-27 1:49 ` [PATCHSET v30.1 12/15] xfs: online repair of symbolic links Darrick J. Wong
2024-03-27 2:05 ` [PATCH 1/1] " Darrick J. Wong
2024-03-27 16:53 ` Christoph Hellwig
2024-03-29 20:44 ` Darrick J. Wong
2024-03-29 20:58 ` Darrick J. Wong
2024-04-03 5:12 ` [PATCHSET v30.2] " Darrick J. Wong
2024-04-03 5:12 ` [PATCH 1/3] xfs: expose xfs_bmap_local_to_extents for online repair Darrick J. Wong
2024-04-03 11:43 ` Christoph Hellwig
2024-04-03 5:12 ` [PATCH 2/3] xfs: pass the owner to xfs_symlink_write_target Darrick J. Wong
2024-04-03 11:43 ` Christoph Hellwig
2024-04-03 5:12 ` [PATCH 3/3] xfs: online repair of symbolic links Darrick J. Wong
2024-04-03 11:44 ` Christoph Hellwig
2024-03-27 1:49 ` [PATCHSET v30.1 13/15] xfs: online fsck of iunlink buckets Darrick J. Wong
2024-03-27 2:06 ` [PATCH 1/3] xfs: check AGI unlinked inode buckets Darrick J. Wong
2024-03-27 2:06 ` [PATCH 2/3] xfs: hoist AGI repair context to a heap object Darrick J. Wong
2024-03-27 2:06 ` [PATCH 3/3] xfs: repair AGI unlinked inode bucket lists Darrick J. Wong
2024-03-27 1:49 ` [PATCHSET v30.1 14/15] xfs: inode-related repair fixes Darrick J. Wong
2024-03-27 2:06 ` [PATCH 1/4] xfs: check unused nlink fields in the ondisk inode Darrick J. Wong
2024-03-27 2:07 ` [PATCH 2/4] xfs: try to avoid allocating from sick inode clusters Darrick J. Wong
2024-03-27 2:07 ` [PATCH 3/4] xfs: pin inodes that would otherwise overflow link count Darrick J. Wong
2024-03-27 2:07 ` [PATCH 4/4] xfs: create subordinate scrub contexts for xchk_metadata_inode_subtype Darrick J. Wong
2024-03-27 1:50 ` [PATCHSET v30.1 15/15] xfs: less heavy locks during fstrim Darrick J. Wong
2024-03-27 2:07 ` [PATCH 1/1] xfs: fix severe performance problems when fstrimming a subset of an AG Darrick J. Wong
2024-03-27 11:35 ` Christoph Hellwig
2024-03-29 21:35 ` Darrick J. Wong
2024-03-30 5:38 ` Christoph Hellwig
2024-03-30 21:15 ` Dave Chinner
2024-03-31 22:44 ` Darrick J. Wong
2024-03-27 22:15 ` Dave Chinner
2024-03-29 22:51 ` Darrick J. Wong
2024-03-30 21:51 ` Dave Chinner
2024-03-31 22:44 ` Darrick J. Wong
2024-04-01 22:12 ` Dave Chinner
2024-04-03 5:07 ` [PATCH v30.2 " Darrick J. Wong
2024-04-04 21:46 ` Dave Chinner
-- strict thread matches above, loose matches on Subject: below --
2024-02-27 2:17 [PATCHSET v29.4 01/13] xfs: improve log incompat feature handling Darrick J. Wong
2024-02-27 2:19 ` [PATCH 1/2] xfs: only clear log incompat flags at clean unmount Darrick J. Wong
2024-02-27 18:08 ` Christoph Hellwig
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