mm: memcg: fix memcg file_dirty numa stat

The kernel updates the per-node NR_FILE_DIRTY stats on page migration
but not the memcg numa stats.

That was not an issue until recently the commit 5f9a4f4a ("mm:
memcontrol: add the missing numa_stat interface for cgroup v2") exposed
numa stats for the memcg.

So fix the file_dirty per-memcg numa stat.

Link: https://lkml.kernel.org/r/20210108155813.2914586-1-shakeelb@google.com
Fixes: 5f9a4f4a ("mm: memcontrol: add the missing numa_stat interface for cgroup v2")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/migrate.c

@@ -500,9 +500,9 @@ int migrate_page_move_mapping(struct address_space *mapping,
 			__inc_lruvec_state(new_lruvec, NR_SHMEM);
 		}
 		if (dirty && mapping_can_writeback(mapping)) {
-			__dec_node_state(oldzone->zone_pgdat, NR_FILE_DIRTY);
+			__dec_lruvec_state(old_lruvec, NR_FILE_DIRTY);
 			__dec_zone_state(oldzone, NR_ZONE_WRITE_PENDING);
-			__inc_node_state(newzone->zone_pgdat, NR_FILE_DIRTY);
+			__inc_lruvec_state(new_lruvec, NR_FILE_DIRTY);
 			__inc_zone_state(newzone, NR_ZONE_WRITE_PENDING);
 		}
 	}