Re: [PATCH v3 10/9] fs: Remove page_mkwrite_check_truncate()

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

On Fri, 2025-02-21 at 20:44 +0000, Matthew Wilcox (Oracle) wrote:
> All callers of this function have now been converted to use
> folio_mkwrite_check_truncate().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  include/linux/pagemap.h | 28 ----------------------------
>  1 file changed, 28 deletions(-)
> 
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index 8c52a637d42b..798e2e39c6e2 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -1579,34 +1579,6 @@ static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio,
>  	return offset;
>  }
>  
> -/**
> - * page_mkwrite_check_truncate - check if page was truncated
> - * @page: the page to check
> - * @inode: the inode to check the page against
> - *
> - * Returns the number of bytes in the page up to EOF,
> - * or -EFAULT if the page was truncated.
> - */
> -static inline int page_mkwrite_check_truncate(struct page *page,
> -					      struct inode *inode)
> -{
> -	loff_t size = i_size_read(inode);
> -	pgoff_t index = size >> PAGE_SHIFT;
> -	int offset = offset_in_page(size);
> -
> -	if (page->mapping != inode->i_mapping)
> -		return -EFAULT;
> -
> -	/* page is wholly inside EOF */
> -	if (page->index < index)
> -		return PAGE_SIZE;
> -	/* page is wholly past EOF */
> -	if (page->index > index || !offset)
> -		return -EFAULT;
> -	/* page is partially inside EOF */
> -	return offset;
> -}
> -
>  /**
>   * i_blocks_per_folio - How many blocks fit in this folio.
>   * @inode: The inode which contains the blocks.

As far as I can see, we exchanged the ceph_page_mkwrite() in [PATCH v3 2/9]:

-		if (page_mkwrite_check_truncate(page, inode) < 0) {
-			unlock_page(page);
+		if (folio_mkwrite_check_truncate(folio, inode) < 0) {
+			folio_unlock(folio);

And it was only user of page_mkwrite_check_truncate(). So, we can remove the
page_mkwrite_check_truncate() functionality.

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

Thanks,
Slava.