linux-ext4 - [PATCH 0/7] ext4: Cleanup data=journal writeback path

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Date:   Wed, 11 Jan 2023 16:43:24 +0100
From:   Jan Kara <jack@...e.cz>
To:     Ted Tso <tytso@....edu>
Cc:     <linux-ext4@...r.kernel.org>, Jan Kara <jack@...e.cz>
Subject: [PATCH 0/7] ext4: Cleanup data=journal writeback path

Hello,

this patch series implements promised cleanup of ext4 data=journal writeback
path. That way we can get rid of last remnants of old support for .writepage
callback and mostly unify this writeback path with standard data handling
modes. We also update some of the stale comments regarding data=journal mode
along the way.

Note that patch 3 (ext4: Mark page for delayed dirtying only if it is pinned)
currently breaks somewhat the data=journal guarantees if mapped page cache is
used as a buffer for direct IO read because that path does not pin pages yet
(David Howels is working on it). But I figured this is not a huge deal for a
cornercase usecase of a cornercase configuration and keeping marking page for
delayed dirtying unconditionally is problematic as checkpointing dirties the
page as well so it is effectively permanently added to the journal. It was
problematic already in the past and happened to work only by luck.

								Honza