btrfs: convert extent_write_cache_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().  Now also supports large folios.

Link: https://lkml.kernel.org/r/20230104211448.4804-8-vishal.moola@gmail.com
Signed-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

@@ -2993,8 +2993,8 @@ static int extent_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 */
 	pgoff_t done_index;
@@ -3014,7 +3014,7 @@ static int extent_write_cache_pages(struct address_space *mapping,
 	if (!igrab(inode))
 		return 0;
 
-	pagevec_init(&pvec);
+	folio_batch_init(&fbatch);
 	if (wbc->range_cyclic) {
 		index = mapping->writeback_index; /* Start from prev offset */
 		end = -1;
@@ -3052,14 +3052,14 @@ retry:
 		tag_pages_for_writeback(mapping, index, end);
 	done_index = index;
 	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];
 
-			done_index = page->index + 1;
+			done_index = folio->index + folio_nr_pages(folio);
 			/*
 			 * At this point we hold neither the i_pages lock nor
 			 * the page lock: the page may be truncated or
@@ -3067,29 +3067,29 @@ retry:
 			 * or even swizzled back from swapper_space to
 			 * tmpfs file mapping
 			 */
-			if (!trylock_page(page)) {
+			if (!folio_trylock(folio)) {
 				submit_write_bio(bio_ctrl, 0);
-				lock_page(page);
+				folio_lock(folio);
 			}
 
-			if (unlikely(page->mapping != mapping)) {
-				unlock_page(page);
+			if (unlikely(folio->mapping != mapping)) {
+				folio_unlock(folio);
 				continue;
 			}
 
 			if (wbc->sync_mode != WB_SYNC_NONE) {
-				if (PageWriteback(page))
+				if (folio_test_writeback(folio))
 					submit_write_bio(bio_ctrl, 0);
-				wait_on_page_writeback(page);
+				folio_wait_writeback(folio);
 			}
 
-			if (PageWriteback(page) ||
-			    !clear_page_dirty_for_io(page)) {
-				unlock_page(page);
+			if (folio_test_writeback(folio) ||
+			    !folio_clear_dirty_for_io(folio)) {
+				folio_unlock(folio);
 				continue;
 			}
 
-			ret = __extent_writepage(page, wbc, bio_ctrl);
+			ret = __extent_writepage(&folio->page, wbc, bio_ctrl);
 			if (ret < 0) {
 				done = 1;
 				break;
@@ -3102,7 +3102,7 @@ retry:
 			 */
 			nr_to_write_done = wbc->nr_to_write <= 0;
 		}
-		pagevec_release(&pvec);
+		folio_batch_release(&fbatch);
 		cond_resched();
 	}
 	if (!scanned && !done) {