On Thu, Oct 14, 2021 at 10:38 AM Darrick J. Wong [off-list ref] wrote:

On Tue, Sep 28, 2021 at 02:23:10PM +0800, Shiyang Ruan wrote:

quoted

In fsdax mode, WRITE and ZERO on a shared extent need CoW performed.
After that, new allocated extents needs to be remapped to the file.
So, add a CoW identification in ->iomap_begin(), and implement
->iomap_end() to do the remapping work.

Signed-off-by: Shiyang Ruan <redacted>

I think this patch looks good, so:
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

A big thank you to Shiyang for persisting in getting this series
finished! :)

Judging from the conversation Christoph and I had the last time this
patchset was submitted, I gather the last big remaining issue is the use
of page->mapping for hw poison.  So I'll go take a look at "fsdax:
introduce FS query interface to support reflink" now.

The other blocker was enabling mounting dax filesystems on a
dax-device rather than a block device. I'm actively refactoring the
nvdimm subsystem side of that equation, but could use help with the
conversion of the xfs mount path. Christoph, might you have that in
your queue?