From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Brian Foster <bfoster@redhat.com>,
linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org
Subject: Re: [PATCH v3 2/8] xfs: flush dirty pagecache over hole in zoned mode zero range
Date: Mon, 9 Mar 2026 23:47:23 -0700 [thread overview]
Message-ID: <aa--e9z5MZ9MOAFu@infradead.org> (raw)
In-Reply-To: <20260309172219.GM6033@frogsfrogsfrogs>
On Mon, Mar 09, 2026 at 10:22:19AM -0700, Darrick J. Wong wrote:
> Why does the mapping disappear out of both data and cow forks between
> writeback setup and completion? IIRC it is because the writeback ioend
> effectively owns the unwritten mapping. We want another writer thread
> to see the hole and reserve its own out-of-place write because the write
> mapping that writeback's working on is immutable once the disk actually
> writes it. Right?
Mostly because we don't have good code to turn a COW fork delalloc
mapping into a data fork written one. Unwritten extents do not actually
exist for zoned RT forks.
> I wonder if we could stash a delalloc mapping in the cow fork with zero
> indlen during writeback to signal "get a real zoned space reservation"?
What would that help with?
next prev parent reply other threads:[~2026-03-10 6:47 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-09 13:44 [PATCH v3 0/8] iomap, xfs: improve zero range flushing and lookup Brian Foster
2026-03-09 13:44 ` [PATCH v3 1/8] xfs: fix iomap hole map reporting for zoned zero range Brian Foster
2026-03-09 17:11 ` Darrick J. Wong
2026-03-09 18:18 ` Brian Foster
2026-03-10 14:47 ` Darrick J. Wong
2026-03-10 6:45 ` Christoph Hellwig
2026-03-09 13:45 ` [PATCH v3 2/8] xfs: flush dirty pagecache over hole in zoned mode " Brian Foster
2026-03-09 17:22 ` Darrick J. Wong
2026-03-09 18:19 ` Brian Foster
2026-03-10 6:47 ` Christoph Hellwig [this message]
2026-03-10 14:48 ` Darrick J. Wong
2026-03-10 6:45 ` Christoph Hellwig
2026-03-09 13:45 ` [PATCH v3 3/8] iomap, xfs: lift zero range hole mapping flush into xfs Brian Foster
2026-03-09 17:40 ` Darrick J. Wong
2026-03-10 6:47 ` Christoph Hellwig
2026-03-09 13:45 ` [PATCH v3 4/8] xfs: flush eof folio before insert range size update Brian Foster
2026-03-09 17:32 ` Darrick J. Wong
2026-03-09 18:24 ` Brian Foster
2026-03-09 13:45 ` [PATCH v3 5/8] xfs: look up cow fork extent earlier for buffered iomap_begin Brian Foster
2026-03-09 13:45 ` [PATCH v3 6/8] xfs: only flush when COW fork blocks overlap data fork holes Brian Foster
2026-03-09 17:47 ` Darrick J. Wong
2026-03-09 13:45 ` [PATCH v3 7/8] xfs: replace zero range flush with folio batch Brian Foster
2026-03-09 17:48 ` Darrick J. Wong
2026-03-09 13:45 ` [PATCH v3 8/8] xfs: report cow mappings with dirty pagecache for iomap zero range Brian Foster
2026-03-09 17:56 ` Darrick J. Wong
2026-03-09 18:31 ` Brian Foster
2026-03-09 18:38 ` Darrick J. Wong
2026-03-10 6:50 ` Christoph Hellwig
2026-03-10 14:52 ` Darrick J. Wong
2026-03-10 14:59 ` Christoph Hellwig
2026-03-10 6:49 ` Christoph Hellwig
2026-03-10 6:45 ` [PATCH v3 0/8] iomap, xfs: improve zero range flushing and lookup Christoph Hellwig
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