[PATCH v6 00/11] fuse: support large folios

[Joanne Koong <joannelkoong@gmail.com>]

This patchset adds support for large folios in fuse.

This does not yet switch fuse to using large folios. Using large folios in
fuse is dependent on adding granular dirty-page tracking. This will be done
in a separate patchset that will have fuse use iomap [1]. There also needs
to be a followup (also part of future work) for having dirty page balancing
not tank performance for unprivileged servers where bdi limits lead to subpar
throttling [1], before enabling large folios for fuse.

[1] https://lore.kernel.org/linux-fsdevel/CAJnrk1a38pv3OgFZRfdTiDMXuPWuBgN8KY47XfOsYHj=N2wxAg@mail.gmail.com/#t

Changelog:
v5:
https://lore.kernel.org/linux-fsdevel/20250426000828.3216220-1-joannelkoong@gmail.com/
v5 -> v6:
* Add Bernd's reviewed-bys
* Iniitalize err to 0 for refactoring fuse_fill_write_pages()
  (Dan and syzbot)
* Add comment for readahead about size of large folio (Bernd)
* Use WARN_ON for readahead size sanity-checking

v4:
https://lore.kernel.org/linux-fsdevel/20250123012448.2479372-1-joannelkoong@gmail.com/
v4 -> v5:
* Now that temp pages are removed in FUSE, resubmit v3.
 
v3:
https://lore.kernel.org/linux-fsdevel/20241213221818.322371-1-joannelkoong@gmail.com/
v3 -> v4:
* Add Jeff's reviewed-bys
* Drop writeback large folios changes, drop turning large folios on. These
  will be part of a separate future patchset

v2:
https://lore.kernel.org/linux-fsdevel/20241125220537.3663725-1-joannelkoong@gmail.com/
v2 -> v3:
* Fix direct io parsing to check each extracted page instead of assuming all
  pages in a large folio will be used (Matthew)

v1:
https://lore.kernel.org/linux-fsdevel/20241109001258.2216604-1-joannelkoong@gmail.com/
v1 -> v2:
* Change naming from "non-writeback write" to "writethrough write"
* Fix deadlock for writethrough writes by calling fault_in_iov_iter_readable()
* first
  before __filemap_get_folio() (Josef)
* For readahead, retain original folio_size() for descs.length (Josef)
* Use folio_zero_range() api in fuse_copy_folio() (Josef)
* Add Josef's reviewed-bys

Joanne Koong (11):
  fuse: support copying large folios
  fuse: support large folios for retrieves
  fuse: refactor fuse_fill_write_pages()
  fuse: support large folios for writethrough writes
  fuse: support large folios for folio reads
  fuse: support large folios for symlinks
  fuse: support large folios for stores
  fuse: support large folios for queued writes
  fuse: support large folios for readahead
  fuse: optimize direct io large folios processing
  fuse: support large folios for writeback

 fs/fuse/dev.c        | 126 ++++++++++++++++++-----------------
 fs/fuse/dir.c        |   8 +--
 fs/fuse/file.c       | 153 +++++++++++++++++++++++++++++--------------
 fs/fuse/fuse_dev_i.h |   2 +-
 4 files changed, 172 insertions(+), 117 deletions(-)

-- 
2.47.1