Re: [PATCH v3] xfs: fix exchange-range reflink flag clearing issue with INO1_WRITTEN

On Tue, 28 Jul 2026 15:19:10 +0800, Lin Jiapeng wrote:
> When exchanging two full-file ranges, xmi_can_exchange_reflink_flags()
> can move the reflink inode flag from the file that currently has it to
> the other file, as long as exactly one side is marked.  This assumes
> that the file contents, and therefore all shared extents, are exchanged.
> 
> That assumption is not true when XFS_EXCHMAPS_INO1_WRITTEN is set.
> xfs_exchmaps_can_skip_mapping() can skip hole and unwritten mappings
> from file1, so an exchange can complete without moving every mapping
> that the earlier flag-swap decision accounted for.  In that case the
> post-operation cleanup can clear the reflink flag from an inode that
> still owns shared written extents.  Later writes then take the
> non-reflink write path and may update blocks that should still have
> been protected by CoW, which shows up as data corruption between
> reflink-related files.
> 
> [...]

Applied to for-next, thanks!

[1/1] xfs: fix exchange-range reflink flag clearing issue with INO1_WRITTEN
      commit: b2d5a81dae385333f9734910277fbf94c78bd17f

Best regards,
-- 
Carlos Maiolino <[email protected]>