nilfs2: convert nilfs_btree_lookup_dirty_buffers() 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 1 call to
compound_head().

Link: https://lkml.kernel.org/r/20230104211448.4804-21-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/btree.c

@@ -2150,7 +2150,7 @@ static void nilfs_btree_lookup_dirty_buffers(struct nilfs_bmap *btree,
 	struct inode *btnc_inode = NILFS_BMAP_I(btree)->i_assoc_inode;
 	struct address_space *btcache = btnc_inode->i_mapping;
 	struct list_head lists[NILFS_BTREE_LEVEL_MAX];
-	struct pagevec pvec;
+	struct folio_batch fbatch;
 	struct buffer_head *bh, *head;
 	pgoff_t index = 0;
 	int level, i;
@@ -2160,19 +2160,19 @@ static void nilfs_btree_lookup_dirty_buffers(struct nilfs_bmap *btree,
 	     level++)
 		INIT_LIST_HEAD(&lists[level]);
 
-	pagevec_init(&pvec);
+	folio_batch_init(&fbatch);
 
-	while (pagevec_lookup_tag(&pvec, btcache, &index,
-					PAGECACHE_TAG_DIRTY)) {
-		for (i = 0; i < pagevec_count(&pvec); i++) {
-			bh = head = page_buffers(pvec.pages[i]);
+	while (filemap_get_folios_tag(btcache, &index, (pgoff_t)-1,
+				PAGECACHE_TAG_DIRTY, &fbatch)) {
+		for (i = 0; i < folio_batch_count(&fbatch); i++) {
+			bh = head = folio_buffers(fbatch.folios[i]);
 			do {
 				if (buffer_dirty(bh))
 					nilfs_btree_add_dirty_buffer(btree,
 								     lists, bh);
 			} while ((bh = bh->b_this_page) != head);
 		}
-		pagevec_release(&pvec);
+		folio_batch_release(&fbatch);
 		cond_resched();
 	}