[Devel] [PATCH RH9 v3 0/8] allow to seek holes in block devices

[Andrey Zhadchenko]

We need to be able to know if and where the image is sparse during
backups.
Implement blockdev and dm infrastructure, add an ability to find
holes for dm-qcow2, dm-ploop, dm-push-backup
After this patches llseek with SEEK_HOLES and SEEK_DATA can be used
with block devices

Feature: dm: implement SEEK_HOLE for dm-qcow2 and dm-ploop

v2:
 - s/find_hole/llseek_hole/
 - add new patch with calc_front_qio_bytes() helper
 - rework dm-qcow2 llseek_hole function

v3:
 - add new helper blkdev_llseek_wrapper() to cover common edge cases
 - rework calc_front_qio_bytes() to increase clarity

Andrey Zhadchenko (8):
  block/fops: add llseek_hole to blockdevops
  dm: add llseek_hole infrastructure
  dm/push_backup: add llseek_hole proxy
  dm/dm-qcow2: add calc_front_qio_bytes() helper
  dm/dm-qcow2: add llseek_hole
  dm/dm-ploop: reinforce some defines
  dm/dm-ploop: allow to check if cluster is locked
  dm/dm-ploop: add llseek_hole

 block/fops.c                  |  38 +++++
 drivers/md/dm-ploop-map.c     |  44 ++++-
 drivers/md/dm-ploop-target.c  |   1 +
 drivers/md/dm-ploop.h         |   9 +-
 drivers/md/dm-push-backup.c   |  12 ++
 drivers/md/dm-qcow2-map.c     | 297 ++++++++++++++++++++++++++++++++--
 drivers/md/dm-qcow2-target.c  |   1 +
 drivers/md/dm-qcow2.h         |   2 +
 drivers/md/dm.c               |  41 +++++
 include/linux/blkdev.h        |   1 +
 include/linux/device-mapper.h |   4 +
 11 files changed, 432 insertions(+), 18 deletions(-)

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2.39.3