Re: [PATCH 4/5] ceph: Convert ceph_zero_partial_page() to use a folio

[Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>]

On Thu, 2025-06-12 at 15:34 +0100, Matthew Wilcox (Oracle) wrote:
> Retrieve a folio from the pagecache instead of a page and operate on it.
> Removes several hidden calls to compound_head() along with calls to
> deprecated functions like wait_on_page_writeback() and find_lock_page().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  fs/ceph/file.c | 21 ++++++++++-----------
>  1 file changed, 10 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index a7254cab44cc..d5c674d2ba8a 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -2530,18 +2530,17 @@ static loff_t ceph_llseek(struct file *file, loff_t offset, int whence)
>  	return generic_file_llseek(file, offset, whence);
>  }
>  
> -static inline void ceph_zero_partial_page(
> -	struct inode *inode, loff_t offset, unsigned size)
> +static inline void ceph_zero_partial_page(struct inode *inode,
> +		loff_t offset, size_t size)
>  {
> -	struct page *page;
> -	pgoff_t index = offset >> PAGE_SHIFT;
> -
> -	page = find_lock_page(inode->i_mapping, index);
> -	if (page) {
> -		wait_on_page_writeback(page);
> -		zero_user(page, offset & (PAGE_SIZE - 1), size);
> -		unlock_page(page);
> -		put_page(page);
> +	struct folio *folio;
> +
> +	folio = filemap_lock_folio(inode->i_mapping, offset >> PAGE_SHIFT);
> +	if (folio) {
> +		folio_wait_writeback(folio);
> +		folio_zero_range(folio, offset_in_folio(folio, offset), size);
> +		folio_unlock(folio);
> +		folio_put(folio);
>  	}
>  }
>  

Looks really good. And filemap_lock_folio() is more efficient than
find_lock_page() now.

Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>

Thanks,
Slava.