[PATCH 01/19] writeback: fix done_index when hitting the wbc->nr_to_write

[Christoph Hellwig <hch@lst.de>]

When write_cache_pages finishes writing out a folio, it fails to update
done_index to account for the number of pages in the folio just written.
That means when range_cyclic writeback is restarted, it will be
restarted at this folio instead of after it as it should.  Fix that
by updating done_index before breaking out of the loop.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
---
 mm/page-writeback.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index cd4e4ae77c40ae..ef2334291a7270 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2505,6 +2505,7 @@ int write_cache_pages(struct address_space *mapping,
 			 * keep going until we have written all the pages
 			 * we tagged for writeback prior to entering this loop.
 			 */
+			done_index = folio->index + nr;
 			wbc->nr_to_write -= nr;
 			if (wbc->nr_to_write <= 0 &&
 			    wbc->sync_mode == WB_SYNC_NONE) {
-- 
2.39.2