[PATCHSET RFC v4 4/6] fuse2fs: use fuse iomap data paths for better file I/O performance

Darrick J. Wong
2025-08-21T00:50:09Z

Hi all,

This series improves the performance (and correctness for some
filesystems) by adding the ability to cache iomap mappings in the
kernel. For filesystems that can change mapping states during pagecache
writeback (e.g. unwritten extent conversion) this is absolutely
necessary to deal with races with writes to the pagecache because
writeback does not take i_rwsem. For everyone else, it simply
eliminates roundtrips to userspace.

If you're going to start using this code, I strongly recommend pulling
from my git trees, which are linked below.

Comments and questions are, as always, welcome.

e2fsprogs git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/e2fsprogs.git/log/?h=fuse2fs-iomap-cache
---
Commits in this patchset:
* fuse2fs: enable caching of iomaps
* fuse2fs: be smarter about caching iomaps
---
misc/fuse2fs.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
misc/fuse4fs.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 91 insertions(+)