[Cluster-devel] RFC: switch iomap to an iterator model

[Christoph Hellwig]

Hi all,

this series replies the existing callback-based iomap_apply to an iter based
model.  The prime aim here is to simply the DAX reflink support, which
requires iterating through two inodes, something that is rather painful
with the apply model.  It also helps to kill an indirect call per segment
as-is.  Compared to the earlier patchset from Matthew Wilcox that this
series is based upon it does not eliminate all indirect calls, but as the
upside it does not change the file systems at all (except for the btrfs
and gfs2 hooks which have slight prototype changes).

This passes basic testing on XFS for block based file systems.  The DAX
changes are entirely untested as I haven't managed to get pmem work in
recent qemu.

Diffstat:
 b/fs/btrfs/inode.c       |    5 
 b/fs/buffer.c            |    4 
 b/fs/dax.c               |  578 ++++++++++++++++++++++-------------------------
 b/fs/gfs2/bmap.c         |    5 
 b/fs/internal.h          |    4 
 b/fs/iomap/Makefile      |    2 
 b/fs/iomap/buffered-io.c |  344 +++++++++++++--------------
 b/fs/iomap/direct-io.c   |  162 ++++++-------
 b/fs/iomap/fiemap.c      |  101 +++-----
 b/fs/iomap/iter.c        |   74 ++++++
 b/fs/iomap/seek.c        |   88 +++----
 b/fs/iomap/swapfile.c    |   38 +--
 b/fs/iomap/trace.h       |   35 +-
 b/include/linux/iomap.h  |   73 ++++-
 fs/iomap/apply.c         |   99 --------
 15 files changed, 777 insertions(+), 835 deletions(-)