[Devel] [PATCH VZ10 0/6] dm-qcow: lseek improvements

Andrey Zhadchenko andrey.zhadchenko at virtuozzo.com
Mon Aug 10 15:29:54 MSK 2026


This patchset is mostly about improving dm-qcow2 lseek speed. L2 md
pages can now be scanned in batch with simple for() instead of heavy
parse_metadata(). Seek qios for backing images are now called with
a range bigger than 1 cluster if possible.
Also fix a few clamping bugs and use correct comparison for seek
modes.

Andrey Zhadchenko (6):
  drivers/md/dm-qcow2: fix lower delta seek window clamp
  drivers/md/dm-qcow2: keep seek parse window within limit
  drivers/md/dm-qcow2: fix seek constant comparison
  drivers/md/dm-qcow2: fix seek skip to the next L2 table
  drivers/md/dm-qcow2: scan lower delta in one pass over empty L1 entry
  drivers/md/dm-qcow2: seek unallocated L2 entries in one pass within md

 drivers/md/dm-qcow2-map.c | 111 ++++++++++++++++++++++++++------------
 1 file changed, 78 insertions(+), 33 deletions(-)

-- 
2.43.5



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