btrfs: convert copy_inline_to_page() to use folio

The old page API is being gradually replaced and converted to use folio
to improve code readability and avoid repeated conversion between page
and folio. Moreover find_or_create_page() is compatible API, and it can
replaced with __filemap_get_folio(). Some interfaces have been converted
to use folio before, so the conversion operation from page can be
eliminated here.

Signed-off-by: Li Zetao <[e-mail]>
Reviewed-by: David Sterba <[e-mail]>
Signed-off-by: David Sterba <[e-mail]>

fs/btrfs/reflink.c

···
 	const size_t inline_size = size - btrfs_file_extent_calc_inline_size(0);
 	char *data_start = inline_data + btrfs_file_extent_calc_inline_size(0);
 	struct extent_changeset *data_reserved = NULL;
-	struct page *page = NULL;
+	struct folio *folio = NULL;
 	struct address_space *mapping = inode->vfs_inode.i_mapping;
 	int ret;
 
···
 	if (ret)
 		goto out;
 
-	page = find_or_create_page(mapping, file_offset >> PAGE_SHIFT,
-				   btrfs_alloc_write_mask(mapping));
-	if (!page) {
+	folio = __filemap_get_folio(mapping, file_offset >> PAGE_SHIFT,
+					FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
+					btrfs_alloc_write_mask(mapping));
+	if (IS_ERR(folio)) {
 		ret = -ENOMEM;
 		goto out_unlock;
 	}
 
-	ret = set_page_extent_mapped(page);
+	ret = set_folio_extent_mapped(folio);
 	if (ret < 0)
 		goto out_unlock;
 
···
 	set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &inode->runtime_flags);
 
 	if (comp_type == BTRFS_COMPRESS_NONE) {
-		memcpy_to_page(page, offset_in_page(file_offset), data_start,
-			       datal);
+		memcpy_to_folio(folio, offset_in_folio(folio, file_offset), data_start,
+					datal);
 	} else {
-		ret = btrfs_decompress(comp_type, data_start, page_folio(page),
-				       offset_in_page(file_offset),
+		ret = btrfs_decompress(comp_type, data_start, folio,
+				       offset_in_folio(folio, file_offset),
 				       inline_size, datal);
 		if (ret)
 			goto out_unlock;
-		flush_dcache_page(page);
+		flush_dcache_folio(folio);
 	}
 
 	/*
···
 	 * So what's in the range [500, 4095] corresponds to zeroes.
 	 */
 	if (datal < block_size)
-		memzero_page(page, datal, block_size - datal);
+		folio_zero_range(folio, datal, block_size - datal);
 
-	btrfs_folio_set_uptodate(fs_info, page_folio(page), file_offset, block_size);
-	btrfs_folio_clear_checked(fs_info, page_folio(page), file_offset, block_size);
-	btrfs_folio_set_dirty(fs_info, page_folio(page), file_offset, block_size);
+	btrfs_folio_set_uptodate(fs_info, folio, file_offset, block_size);
+	btrfs_folio_clear_checked(fs_info, folio, file_offset, block_size);
+	btrfs_folio_set_dirty(fs_info, folio, file_offset, block_size);
 out_unlock:
-	if (page) {
-		unlock_page(page);
-		put_page(page);
+	if (!IS_ERR(folio)) {
+		folio_unlock(folio);
+		folio_put(folio);
 	}
 	if (ret)
 		btrfs_delalloc_release_space(inode, data_reserved, file_offset,