From: Jan Kara <jack@suse.cz>
To: Theodore Ts'o <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>,
Ext4 Developers List <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH REBASED 0/7] ext4: Cleanup data=journal writeback path
Date: Fri, 3 Mar 2023 11:38:06 +0100 [thread overview]
Message-ID: <20230303103806.77ipbtzz7n5hawim@quack3> (raw)
In-Reply-To: <20230303092939.kq4mlowe2y2x6ncx@quack3>
On Fri 03-03-23 10:29:39, Jan Kara wrote:
> On Thu 02-03-23 08:37:35, Theodore Ts'o wrote:
> > On Tue, Feb 28, 2023 at 02:58:54PM +0100, Jan Kara wrote:
> > >
> > > Regarding the warning somehow there are dirty pages left after the
> > > procedures freeze_super() goes through to flush all dirty data. That is not
> > > too surprising since in data=journal mode pages get (as a surprise to
> > > freezing code) dirtied when transaction commits. I thought we have this
> > > covered by jbd2_journal_flush() call in ext4_freeze() but maybe there are
> > > some stranded PageDirty bits left? It needs more debugging...
> >
> > So the question I have is whether this is a bug that was always there,
> > or perhaps code changes affected the timing, so that it was much more
> > likely to happen (although in my testing it's still only triggering
> > about 50% of the time).
> >
> > This warning can mean that data can be lost, especially if someone was
> > doing hibernation, right? We can discuss this at today's ext4 video
> > conference, but I'm inclined to wait until the next merge cycle for
> > this patch series until we can figure out what's going on. Jan, what
> > do you think?
>
> As we discussed in the meeting, I'll have a look into the failure. For now
> I'd keep patches on hold as it is not urgent patchset.
FWIW I'm able to reproduce the issue and also as I'm looking into the
freeze to it was always there in principle. But my patches likely made it
much more probable. I'll have a look what I can do...
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2023-03-03 10:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-28 5:13 [PATCH REBASED 0/7] ext4: Cleanup data=journal writeback path Theodore Ts'o
2023-02-28 5:13 ` [PATCH 1/7] ext4: Update stale comment about write constraints Theodore Ts'o
2023-02-28 5:13 ` [PATCH 2/7] ext4: Use nr_to_write directly in mpage_prepare_extent_to_map() Theodore Ts'o
2023-02-28 5:13 ` [PATCH 3/7] ext4: Mark page for delayed dirtying only if it is pinned Theodore Ts'o
2023-02-28 5:13 ` [PATCH 4/7] ext4: Don't unlock page in ext4_bio_write_page() Theodore Ts'o
2023-02-28 5:13 ` [PATCH 5/7] ext4: Move page unlocking out of mpage_submit_page() Theodore Ts'o
2023-02-28 5:13 ` [PATCH 6/7] ext4: Move mpage_page_done() calls after error handling Theodore Ts'o
2023-02-28 5:13 ` [PATCH 7/7] ext4: Convert data=journal writeback to use ext4_writepages() Theodore Ts'o
2023-02-28 13:58 ` [PATCH REBASED 0/7] ext4: Cleanup data=journal writeback path Jan Kara
2023-03-02 13:37 ` Theodore Ts'o
2023-03-03 9:29 ` Jan Kara
2023-03-03 10:38 ` Jan Kara [this message]
2023-03-08 16:37 ` Jan Kara
2023-03-15 16:16 ` Theodore Ts'o
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