[PATCH v3 00/16] fuse: use iomap for buffered writes + writeback

Joanne Koong
2025-06-24T02:22:58Z

This series adds fuse iomap support for buffered writes and dirty folio
writeback. This is needed so that granular uptodate and dirty tracking can
be used in fuse when large folios are enabled. This has two big advantages.
For writes, instead of the entire folio needing to be read into the page
cache, only the relevant portions need to be. For writeback, only the
dirty portions need to be written back instead of the entire folio.

This patchset is composed of two parts:
a) Christoph's iomap changes (patches 1 to 11) which are taken verbatim
from [1]
b) fuse changes to use iomap (patches 12 to 16)

Please note the following:
* this patchset version temporarily drops the CONFIG_BLOCK iomap refactoring
patches that will be needed to merge in the series. As of now, this breaks
compilation for environments where CONFIG_BLOCK is not set, but the
CONFIG_BLOCK iomap changes will be re-added back in once the core changes
in this patchset are ready to go.
* this patchset does not enable large folios yet. That will be sent out in a
separate future patchset.

This series is on top of commit 86731a2a6 ("Linux 6.16-rc3") in the linux
tree.

Thanks,
Joanne

[1] https://lore.kernel.org/linux-fsdevel/20250617105514.3393938-1-hch@lst.de/

Changeset
-------
v2 -> v3:
* Fix up fuse patches to use iomap APIs from Christoph's patches
* Drop CONFIG_BLOCK patches
* Add patch to use iomap for invalidation and partial uptodateness check
* Add patch for refactoring fuse writeback to use iomap_writepage_ctx inode
v2: https://lore.kernel.org/linux-fsdevel/20250613214642.2903225-1-joannelkoong@gmail.com/

v1 -> v2:
* Drop IOMAP_IN_MEM type and just use IOMAP_MAPPED for fuse
* Separate out new helper functions added to iomap into separate commits
* Update iomap documentation
* Clean up iomap_writeback_dirty_folio() locking logic w/ christoph's
recommendation
* Refactor ->map_blocks() to generic ->writeback_folio()
* Refactor ->submit_ioend() to generic ->writeback_complete()
* Add patch for changing 'count' to 'async_writeback'
* Rebase commits onto linux branch instead of fuse branch
v1: https://lore.kernel.org/linux-fsdevel/20250606233803.1421259-1-joannelkoong@gmail.com/

Christoph Hellwig (7):
iomap: pass more arguments using struct iomap_writepage_ctx
iomap: refactor the writeback interface
iomap: hide ioends from the generic writeback code
iomap: move all ioend handling to ioend.c
iomap: rename iomap_writepage_map to iomap_writeback_folio
iomap: export iomap_writeback_folio
iomap: replace iomap_folio_ops with iomap_write_ops

Joanne Koong (9):
iomap: cleanup the pending writeback tracking in
iomap_writepage_map_blocks
iomap: add public helpers for uptodate state manipulation
iomap: move folio_unlock out of iomap_writeback_folio
iomap: add read_folio_range() handler for buffered writes
fuse: use iomap for buffered writes
fuse: use iomap for writeback
fuse: use iomap for folio laundering
fuse: hook into iomap for invalidating and checking partial
uptodateness
fuse: refactor writeback to use iomap_writepage_ctx inode

Documentation/filesystems/iomap/design.rst | 3 -
.../filesystems/iomap/operations.rst | 51 +-
block/fops.c | 37 +-
fs/fuse/Kconfig | 1 +
fs/fuse/file.c | 327 ++++++-------
fs/gfs2/aops.c | 8 +-
fs/gfs2/bmap.c | 48 +-
fs/gfs2/bmap.h | 1 +
fs/gfs2/file.c | 3 +-
fs/iomap/buffered-io.c | 438 +++++-------------
fs/iomap/internal.h | 1 -
fs/iomap/ioend.c | 220 ++++++++-
fs/iomap/trace.h | 2 +-
fs/xfs/xfs_aops.c | 238 ++++++----
fs/xfs/xfs_file.c | 6 +-
fs/xfs/xfs_iomap.c | 12 +-
fs/xfs/xfs_iomap.h | 1 +
fs/xfs/xfs_reflink.c | 3 +-
fs/zonefs/file.c | 40 +-
include/linux/iomap.h | 81 ++--
20 files changed, 775 insertions(+), 746 deletions(-)

--
2.47.1