On Mon, Aug 25, 2025 at 06:37:05PM -0600, Keith Busch wrote:

On Mon, Aug 25, 2025 at 09:47:44AM +0200, Christoph Hellwig wrote:

quoted

Also with this we should be able to drop the iov_iter_alignment check
for always COW inodes in xfs_file_dio_write.  If you don't feel like
doing that yourself I can add it to my todo list.

I'm unsure about the commit that introduced that behavior, so I think
you should remove it if you know its okay. :)

Yeah.

Specifically, we have this in the comments and commit message:

  check the alignment of each individual iovec segment, as they could
  end up with different I/Os due to the way bio_iov_iter_get_pages works 

bio_iov_iter_get_pages() might submit the segments as separate IO's
anyway for other reasons. I am not sure why the alignment conditions are
handled specifically here.

I'll take another look.  Basically what this wants to prevent is
bio_iov_iter_get_pages creating bios not aligned to file system
block size.