gfs2: convert gfs2_write_cache_jdata() to use filemap_get_folios_tag()

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

Also had to modify and rename gfs2_write_jdata_pagevec() to take in and
utilize folio_batch rather than pagevec and use folios rather than pages. 
gfs2_write_jdata_batch() now supports large folios.

Link: https://lkml.kernel.org/r/20230104211448.4804-18-vishal.moola@gmail.comSigned-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/gfs2/aops.c

@@ -195,67 +195,71 @@ static int gfs2_writepages(struct address_space *mapping,
 }
 
 /**
- * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
+ * gfs2_write_jdata_batch - Write back a folio batch's worth of folios
  * @mapping: The mapping
  * @wbc: The writeback control
- * @pvec: The vector of pages
- * @nr_pages: The number of pages to write
+ * @fbatch: The batch of folios
  * @done_index: Page index
  *
  * Returns: non-zero if loop should terminate, zero otherwise
  */
 
-static int gfs2_write_jdata_pagevec(struct address_space *mapping,
+static int gfs2_write_jdata_batch(struct address_space *mapping,
 				    struct writeback_control *wbc,
-				    struct pagevec *pvec,
-				    int nr_pages,
+				    struct folio_batch *fbatch,
 				    pgoff_t *done_index)
 {
 	struct inode *inode = mapping->host;
 	struct gfs2_sbd *sdp = GFS2_SB(inode);
-	unsigned nrblocks = nr_pages * (PAGE_SIZE >> inode->i_blkbits);
+	unsigned nrblocks;
 	int i;
 	int ret;
+	int nr_pages = 0;
+	int nr_folios = folio_batch_count(fbatch);
+
+	for (i = 0; i < nr_folios; i++)
+		nr_pages += folio_nr_pages(fbatch->folios[i]);
+	nrblocks = nr_pages * (PAGE_SIZE >> inode->i_blkbits);
 
 	ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
 	if (ret < 0)
 		return ret;
 
-	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;
+		*done_index = folio->index;
 
-		lock_page(page);
+		folio_lock(folio);
 
-		if (unlikely(page->mapping != mapping)) {
+		if (unlikely(folio->mapping != mapping)) {
 continue_unlock:
-			unlock_page(page);
+			folio_unlock(folio);
 			continue;
 		}
 
-		if (!PageDirty(page)) {
+		if (!folio_test_dirty(folio)) {
 			/* someone wrote it for us */
 			goto continue_unlock;
 		}
 
-		if (PageWriteback(page)) {
+		if (folio_test_writeback(folio)) {
 			if (wbc->sync_mode != WB_SYNC_NONE)
-				wait_on_page_writeback(page);
+				folio_wait_writeback(folio);
 			else
 				goto continue_unlock;
 		}
 
-		BUG_ON(PageWriteback(page));
-		if (!clear_page_dirty_for_io(page))
+		BUG_ON(folio_test_writeback(folio));
+		if (!folio_clear_dirty_for_io(folio))
 			goto continue_unlock;
 
 		trace_wbc_writepage(wbc, inode_to_bdi(inode));
 
-		ret = __gfs2_jdata_writepage(page, wbc);
+		ret = __gfs2_jdata_writepage(&folio->page, wbc);
 		if (unlikely(ret)) {
 			if (ret == AOP_WRITEPAGE_ACTIVATE) {
-				unlock_page(page);
+				folio_unlock(folio);
 				ret = 0;
 			} else {
 
@@ -268,7 +272,8 @@ static int gfs2_write_jdata_pagevec(struct address_space *mapping,
 				 * not be suitable for data integrity
 				 * writeout).
 				 */
-				*done_index = page->index + 1;
+				*done_index = folio->index +
+					folio_nr_pages(folio);
 				ret = 1;
 				break;
 			}
@@ -305,8 +310,8 @@ static int gfs2_write_cache_jdata(struct address_space *mapping,
 {
 	int ret = 0;
 	int done = 0;
-	struct pagevec pvec;
-	int nr_pages;
+	struct folio_batch fbatch;
+	int nr_folios;
 	pgoff_t writeback_index;
 	pgoff_t index;
 	pgoff_t end;
@@ -315,7 +320,7 @@ static int gfs2_write_cache_jdata(struct address_space *mapping,
 	int range_whole = 0;
 	xa_mark_t tag;
 
-	pagevec_init(&pvec);
+	folio_batch_init(&fbatch);
 	if (wbc->range_cyclic) {
 		writeback_index = mapping->writeback_index; /* prev offset */
 		index = writeback_index;
@@ -341,17 +346,18 @@ static int gfs2_write_cache_jdata(struct address_space *mapping,
 		tag_pages_for_writeback(mapping, index, end);
 	done_index = index;
 	while (!done && (index <= end)) {
-		nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
-				tag);
-		if (nr_pages == 0)
+		nr_folios = filemap_get_folios_tag(mapping, &index, end,
+				tag, &fbatch);
+		if (nr_folios == 0)
 			break;
 
-		ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, &done_index);
+		ret = gfs2_write_jdata_batch(mapping, wbc, &fbatch,
+				&done_index);
 		if (ret)
 			done = 1;
 		if (ret > 0)
 			ret = 0;
-		pagevec_release(&pvec);
+		folio_batch_release(&fbatch);
 		cond_resched();
 	}