ntfs3: Remove an access to page->index

Convert the first page passed to ni_write_frame() to a folio and use
folio_pos() on that instead of open-coding the access to folio->index,
cast & shift.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Konstantin Komarov <[email protected]>

Author: Matthew Wilcox (Oracle)

fs/ntfs3/frecord.c

@@ -2726,9 +2726,10 @@ int ni_write_frame(struct ntfs_inode *ni, struct page **pages,
 {
 	int err;
 	struct ntfs_sb_info *sbi = ni->mi.sbi;
+	struct folio *folio = page_folio(pages[0]);
 	u8 frame_bits = NTFS_LZNT_CUNIT + sbi->cluster_bits;
 	u32 frame_size = sbi->cluster_size << NTFS_LZNT_CUNIT;
-	u64 frame_vbo = (u64)pages[0]->index << PAGE_SHIFT;
+	u64 frame_vbo = folio_pos(folio);
 	CLST frame = frame_vbo >> frame_bits;
 	char *frame_ondisk = NULL;
 	struct page **pages_disk = NULL;