Re: allow file systems to increase the minimum writeback chunk size v2

Christian Brauner
2025-10-29T14:55:26Z

On Fri, 17 Oct 2025 05:45:46 +0200, Christoph Hellwig wrote:
> The relatively low minimal writeback size of 4MiB leads means that
> written back inodes on rotational media are switched a lot. Besides
> introducing additional seeks, this also can lead to extreme file
> fragmentation on zoned devices when a lot of files are cached relative
> to the available writeback bandwidth.
>
> Add a superblock field that allows the file system to override the
> default size, and set it to the zone size for zoned XFS.
>
> [...]

Applied to the vfs-6.19.writeback branch of the vfs/vfs.git tree.
Patches in the vfs-6.19.writeback branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-6.19.writeback

[1/3] writeback: cleanup writeback_chunk_size
https://git.kernel.org/vfs/vfs/c/151d0922bf63
[2/3] writeback: allow the file system to override MIN_WRITEBACK_PAGES
https://git.kernel.org/vfs/vfs/c/90db4d4441f5
[3/3] xfs: set s_min_writeback_pages for zoned file systems