Re: [PATCH 3/7] iomap: optional zero range dirty folio processing

[Christoph Hellwig <hch@infradead.org>]

On Tue, Jun 10, 2025 at 08:21:06AM -0400, Brian Foster wrote:
> Yes.. but I'm not totally sure wrt impact on the fbatch checks quite
> yet. The next thing I wanted to look at is addressing the same unwritten
> mapping vs. dirty folios issue in the seek data/hole path. It's been a
> little while since I last investigated there (and that was also before
> the whole granular advance approach was devised), but IIRC it would look
> rather similar to what this is doing for zero range. That may or may
> not justify just making the batch required for both operations and
> potentially simplifying this logic further. I'll keep that in mind when
> I get to it..

On thing that the batch would be extremely useful for is making
iomap_file_unshare not totally suck by reading in all folios for a
range (not just the dirty ones) similar to the filemap_read path
instead of synchronously reading one block at a time.