f2fs: convert read_node_page() to use folio

Convert to use folio, so that we can get rid of 'page->index' to
prepare for removal of 'index' field in structure page [1].

[1] https://lore.kernel.org/all/Zp8fgUSIBGQ1TN0D@casper.infradead.org/

Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: Li Zetao <lizetao1@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/node.c

@@ -1369,6 +1369,7 @@ struct page *f2fs_new_node_page(struct dnode_of_data *dn, unsigned int ofs)
  */
 static int read_node_page(struct page *page, blk_opf_t op_flags)
 {
+	struct folio *folio = page_folio(page);
 	struct f2fs_sb_info *sbi = F2FS_P_SB(page);
 	struct node_info ni;
 	struct f2fs_io_info fio = {
@@ -1381,21 +1382,21 @@ static int read_node_page(struct page *page, blk_opf_t op_flags)
 	};
 	int err;
 
-	if (PageUptodate(page)) {
+	if (folio_test_uptodate(folio)) {
 		if (!f2fs_inode_chksum_verify(sbi, page)) {
-			ClearPageUptodate(page);
+			folio_clear_uptodate(folio);
 			return -EFSBADCRC;
 		}
 		return LOCKED_PAGE;
 	}
 
-	err = f2fs_get_node_info(sbi, page->index, &ni, false);
+	err = f2fs_get_node_info(sbi, folio->index, &ni, false);
 	if (err)
 		return err;
 
 	/* NEW_ADDR can be seen, after cp_error drops some dirty node pages */
 	if (unlikely(ni.blk_addr == NULL_ADDR || ni.blk_addr == NEW_ADDR)) {
-		ClearPageUptodate(page);
+		folio_clear_uptodate(folio);
 		return -ENOENT;
 	}