Subject: Re: linux-next: manual merge of the folio-iomap tree with the nvdimm tree

From: Stephen Rothwell <[email-masked]>
Date: Fri, 24 Dec 2021 17:24:21 +1100

Hi all,

On Wed, 22 Dec 2021 21:15:36 +1100 Stephen Rothwell <[email-masked]> wrote:
>
> Today's linux-next merge of the folio-iomap tree got a conflict in:
> 
>   fs/iomap/buffered-io.c
> 
> between commit:
> 
>   de291b590286 ("iomap: turn the byte variable in iomap_zero_iter into a ssize_t")
> 
> from the nvdimm tree and commits:
> 
>   a25def1fe568 ("iomap: Convert __iomap_zero_iter to use a folio")
>   4d7bd0eb72e5 ("iomap: Inline __iomap_zero_iter into its caller")
> 
> from the folio-iomap tree.

Thanks to the addition of commit

  9e05e95ca8da ("iomap: Fix error handling in iomap_zero_iter()")

to the nvdimm tree, the resolutions is now as below.

-- 
Cheers,
Stephen Rothwell

diff --cc fs/iomap/buffered-io.c
index d3b1169602fa,c6b3a148e898..000000000000
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@@ -888,19 -908,32 +907,23 @@@ static loff_t iomap_zero_iter(struct io
  		return length;
  
  	do {
- 		unsigned offset = offset_in_page(pos);
- 		ssize_t bytes = min_t(u64, PAGE_SIZE - offset, length);
- 		struct page *page;
+ 		struct folio *folio;
  		int status;
+ 		size_t offset;
+ 		size_t bytes = min_t(u64, SIZE_MAX, length);
  
- 		status = iomap_write_begin(iter, pos, bytes, &page);
 -		if (IS_DAX(iter->inode)) {
 -			s64 tmp = dax_iomap_zero(pos, bytes, iomap);
 -			if (tmp < 0)
 -				return tmp;
 -			bytes = tmp;
 -			goto good;
 -		}
 -
+ 		status = iomap_write_begin(iter, pos, bytes, &folio);
  		if (status)
  			return status;
  
- 		zero_user(page, offset, bytes);
- 		mark_page_accessed(page);
+ 		offset = offset_in_folio(folio, pos);
+ 		if (bytes > folio_size(folio) - offset)
+ 			bytes = folio_size(folio) - offset;
+ 
+ 		folio_zero_range(folio, offset, bytes);
+ 		folio_mark_accessed(folio);
  
- 		bytes = iomap_write_end(iter, pos, bytes, bytes, page);
+ 		bytes = iomap_write_end(iter, pos, bytes, bytes, folio);
 -good:
  		if (WARN_ON_ONCE(bytes == 0))
  			return -EIO;