nilfs2: convert nilfs_copy_dirty_pages() to use filemap_get_folios_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pages_range_tag().  This change removes 8 calls to
compound_head().

Link: https://lkml.kernel.org/r/20230104211448.4804-22-vishal.moola@gmail.comSigned-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/nilfs2/page.c

@@ -240,42 +240,43 @@ static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
 int nilfs_copy_dirty_pages(struct address_space *dmap,
 			   struct address_space *smap)
 {
-	struct pagevec pvec;
+	struct folio_batch fbatch;
 	unsigned int i;
 	pgoff_t index = 0;
 	int err = 0;
 
-	pagevec_init(&pvec);
+	folio_batch_init(&fbatch);
 repeat:
-	if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY))
+	if (!filemap_get_folios_tag(smap, &index, (pgoff_t)-1,
+				PAGECACHE_TAG_DIRTY, &fbatch))
 		return 0;
 
-	for (i = 0; i < pagevec_count(&pvec); i++) {
-		struct page *page = pvec.pages[i], *dpage;
+	for (i = 0; i < folio_batch_count(&fbatch); i++) {
+		struct folio *folio = fbatch.folios[i], *dfolio;
 
-		lock_page(page);
-		if (unlikely(!PageDirty(page)))
-			NILFS_PAGE_BUG(page, "inconsistent dirty state");
+		folio_lock(folio);
+		if (unlikely(!folio_test_dirty(folio)))
+			NILFS_PAGE_BUG(&folio->page, "inconsistent dirty state");
 
-		dpage = grab_cache_page(dmap, page->index);
-		if (unlikely(!dpage)) {
+		dfolio = filemap_grab_folio(dmap, folio->index);
+		if (unlikely(!dfolio)) {
 			/* No empty page is added to the page cache */
 			err = -ENOMEM;
-			unlock_page(page);
+			folio_unlock(folio);
 			break;
 		}
-		if (unlikely(!page_has_buffers(page)))
-			NILFS_PAGE_BUG(page,
+		if (unlikely(!folio_buffers(folio)))
+			NILFS_PAGE_BUG(&folio->page,
 				       "found empty page in dat page cache");
 
-		nilfs_copy_page(dpage, page, 1);
-		__set_page_dirty_nobuffers(dpage);
+		nilfs_copy_page(&dfolio->page, &folio->page, 1);
+		filemap_dirty_folio(folio_mapping(dfolio), dfolio);
 
-		unlock_page(dpage);
-		put_page(dpage);
-		unlock_page(page);
+		folio_unlock(dfolio);
+		folio_put(dfolio);
+		folio_unlock(folio);
 	}
-	pagevec_release(&pvec);
+	folio_batch_release(&fbatch);
 	cond_resched();
 
 	if (likely(!err))