[GIT PULL] iomap: new code for 5.9-rc1

[Darrick J. Wong]

Hi Linus,

Please pull these new changes to the iomap code for 5.9.  The most
notable changes are:

1) iomap no longer invalidate the page cache when performing a direct
read, since doing so is unnecessary and the old directio code doesn't do
that either.

2) iomap embraced the use of returning ENOTBLK from a direct write to
trigger falling back to a buffered write since ext4 already did this and
btrfs wants it for their port.

3) iomap falls back to buffered writes if we're doing a direct write and
the page cache invalidation after the flush fails; this was necessary to
handle a corner case in the btrfs port.

The branch merges cleanly with your HEAD branch as of 15m ago.  Please
let me know if there are any strange problems.

--D

The following changes since commit dcb7fd82c75ee2d6e6f9d8cc71c52519ed52e258:

  Linux 5.8-rc4 (2020-07-05 16:20:22 -0700)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/fs/xfs/xfs-linux.git tags/iomap-5.9-merge-4

for you to fetch changes up to 66143873c6a0b24242f24f65fde70c643b26b4e7:

  iomap: fall back to buffered writes for invalidation failures (2020-07-23 22:45:59 -0700)

----------------------------------------------------------------
New code for 5.9:
- Make sure we call ->iomap_end with a failure code if ->iomap_begin
  failed in any way; some filesystems need to try to undo things.
- Don't invalidate the page cache during direct reads since we already
  sync'd the cache with disk.
- Make direct writes fall back to the page cache if the pre-write
  cache invalidation fails.  This avoids a cache coherency problem.

----------------------------------------------------------------
Andreas Gruenbacher (1):
      iomap: Make sure iomap_end is called after iomap_begin

Christoph Hellwig (2):
      xfs: use ENOTBLK for direct I/O to buffered I/O fallback
      iomap: fall back to buffered writes for invalidation failures

Dave Chinner (1):
      iomap: Only invalidate page cache pages on direct IO writes

 fs/ext4/file.c       |  2 ++
 fs/gfs2/file.c       |  3 ++-
 fs/iomap/apply.c     | 13 +++++++++----
 fs/iomap/direct-io.c | 37 +++++++++++++++++++++----------------
 fs/iomap/trace.h     |  1 +
 fs/xfs/xfs_file.c    |  8 ++++----
 fs/zonefs/super.c    |  7 +++++--
 7 files changed, 44 insertions(+), 27 deletions(-)