Based-on: https://lore.kernel.org/qemu-devel/20240228141501.455989-1-vsementsov@yandex-team.ru/

Useful to make discard-source work in the context of backup fleecing
when the fleecing image has a larger granularity than the backup
target.

Backup/block-copy will use at least this granularity for copy operations
and in particular, discard requests to the backup source will too. If
the granularity is too small, they will just be aligned down in
cbw_co_pdiscard_snapshot() and thus effectively ignored.

Fiona Ebner (2):
  copy-before-write: allow specifying minimum cluster size
  backup: add minimum cluster size to performance options

 block/backup.c             |  2 +-
 block/block-copy.c         | 17 +++++++++++++----
 block/copy-before-write.c  |  5 ++++-
 block/copy-before-write.h  |  1 +
 blockdev.c                 |  3 +++
 include/block/block-copy.h |  1 +
 qapi/block-core.json       | 17 ++++++++++++++---
 7 files changed, 37 insertions(+), 9 deletions(-)

-- 
2.39.2