On 6/11/24 23:13, Christoph Hellwig wrote:

On Tue, Jun 11, 2024 at 05:47:12PM +0700, Shaun Tancheff wrote:

  	const struct address_space_operations *a_ops = mapping->a_ops;
+	size_t chunk = mapping_max_folio_size(mapping);

Better to default chunk to PAGE_SIZE for backward compat
+       size_t chunk = PAGE_SIZE;

  	long status = 0;
  	ssize_t written = 0;
  

Have fs opt in to large folio support:

+       if (mapping_large_folio_support(mapping))
+               chunk = PAGE_SIZE << MAX_PAGECACHE_ORDER;

I don't think you've actually read the code, have you?

I checked from 6.6 to linux-next with this patch and my ext4 VM does not boot without the opt-in.

Almost certainly there is something I am missing, probably not looking at the correct tree.

Thanks!
--Shaun