RFC: map multiple blocks per ->map_blocks in iomap writeback

Christoph Hellwig
2023-11-26T12:47:33Z

Hi all,

this series overhaults a large chunk of the iomap writeback code with
the end result that ->map_blocks can now map multiple blocks at a time,
at least as long as they are all inside the same folio.

Variants of this have passed a lot of testing on XFS, but I haven't even
starting testing it with other file systems. In terms of performance
there is a very slight reduction in large write workloads, but the main
point for me was to enable other work anyway.

Diffstat:
fs/iomap/buffered-io.c | 561 +++++++++++++++++++++++--------------------------
fs/xfs/xfs_aops.c | 6
include/linux/iomap.h | 17 +
3 files changed, 287 insertions(+), 297 deletions(-)