[0/9] f2fs: use iomap for direct I/O

Message

Eric Biggers July 16, 2021, 2:39 p.m. UTC

This series makes f2fs implement direct I/O using iomap_dio_rw() instead
of __blockdev_direct_IO().  In order to do this, it adds f2fs_iomap_ops,
since this is the first use of iomap in f2fs.

The iomap direct I/O implementation is more efficient than the
fs/direct-io.c implementation.  Switching to iomap also avoids the need
to add new features and optimizations to the old implementation.  E.g.,
see https://lore.kernel.org/r/[e-mail] and
https://lore.kernel.org/r/[e-mail].

In general, this series preserves existing f2fs behavior (such as the
conditions for falling back to buffered I/O) and is only an
implementation change.

Patches 1-5 contain cleanups and fixes for f2fs_file_write_iter().
Patch 6 adds f2fs_iomap_ops, patch 7 and 8 switch direct I/O reads and
writes to iomap, and patch 9 removes obsoleted code.

Careful review is appreciated, as I'm not an expert in all areas here.

This series has been tested with xfstests by running 'gce-xfstests -c
f2fs -g auto -X generic/017' with and without this series; no
regressions were seen.  (Some tests fail both before and after.
generic/017 hangs both before and after, so it had to be excluded.)

This series applies to v5.14-rc1.

Eric Biggers (9):
  f2fs: make f2fs_write_failed() take struct inode
  f2fs: remove allow_outplace_dio()
  f2fs: rework write preallocations
  f2fs: reduce indentation in f2fs_file_write_iter()
  f2fs: fix the f2fs_file_write_iter tracepoint
  f2fs: implement iomap operations
  f2fs: use iomap for direct I/O reads
  f2fs: use iomap for direct I/O writes
  f2fs: remove f2fs_direct_IO()

 fs/f2fs/Kconfig             |   1 +
 fs/f2fs/data.c              | 286 +++++++------------------
 fs/f2fs/f2fs.h              |  29 +--
 fs/f2fs/file.c              | 416 +++++++++++++++++++++++++++++-------
 include/trace/events/f2fs.h |  12 +-
 5 files changed, 421 insertions(+), 323 deletions(-)


base-commit: e73f0f0ee7541171d89f2e2491130c7771ba58d3