On Thu, Jun 18, 2026 at 03:26:14PM +0200, Pankaj Raghav (Samsung) wrote:

existing code **does not** overwrite any user data. Here is why:

- xfs_free_file_space (punch hole) punches inward (offset_ru -> end_rd)
  and zeroes out from (offset -> offset_ru) and (end_rd -> end) with
  xfs_zero_range

Ah, right.

- Luckily, even though we consider offset_rd to end_ru in
  alloc_file_space, XFS_BMAPI_ZERO will skip zeroing already written
  edge blocks and only offset_ru -> end_rd are zeroed using unmap zero range.
  ( (offset -> offset_ru) -> EXT_NORM, (offset_ru -> end_rd) -> HOLE,
  (end_rd -> end) -> EXT_NORM)

Oh.  So this was lucky because of the corner cases.  I still think doing
the proper alignment in the higher level code and only calling down for
the area that we really want to zero would be benefitial here, if only
to make the code easier to follow.