btrfs: convert btree_write_cache_pages() to use filemap_get_folio_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pages_range_tag().

Link: https://lkml.kernel.org/r/20230104211448.4804-7-vishal.moola@gmail.comSigned-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/btrfs/extent_io.c

@@ -2865,14 +2865,14 @@ int btree_write_cache_pages(struct address_space *mapping,
 	int ret = 0;
 	int done = 0;
 	int nr_to_write_done = 0;
-	struct pagevec pvec;
-	int nr_pages;
+	struct folio_batch fbatch;
+	unsigned int nr_folios;
 	pgoff_t index;
 	pgoff_t end;		/* Inclusive */
 	int scanned = 0;
 	xa_mark_t tag;
 
-	pagevec_init(&pvec);
+	folio_batch_init(&fbatch);
 	if (wbc->range_cyclic) {
 		index = mapping->writeback_index; /* Start from prev offset */
 		end = -1;
@@ -2895,14 +2895,15 @@ int btree_write_cache_pages(struct address_space *mapping,
 	if (wbc->sync_mode == WB_SYNC_ALL)
 		tag_pages_for_writeback(mapping, index, end);
 	while (!done && !nr_to_write_done && (index <= end) &&
-	       (nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
-			tag))) {
+	       (nr_folios = filemap_get_folios_tag(mapping, &index, end,
+					    tag, &fbatch))) {
 		unsigned i;
 
-		for (i = 0; i < nr_pages; i++) {
-			struct page *page = pvec.pages[i];
+		for (i = 0; i < nr_folios; i++) {
+			struct folio *folio = fbatch.folios[i];
 
-			ret = submit_eb_page(page, wbc, &bio_ctrl, &eb_context);
+			ret = submit_eb_page(&folio->page, wbc, &bio_ctrl,
+					&eb_context);
 			if (ret == 0)
 				continue;
 			if (ret < 0) {
@@ -2917,7 +2918,7 @@ int btree_write_cache_pages(struct address_space *mapping,
 			 */
 			nr_to_write_done = wbc->nr_to_write <= 0;
 		}
-		pagevec_release(&pvec);
+		folio_batch_release(&fbatch);
 		cond_resched();
 	}
 	if (!scanned && !done) {