page_writeback: put account_page_redirty() after set_page_dirty()

Helper account_page_redirty() fixes dirty pages counter for redirtied
pages.  This patch puts it after dirtying and prevents temporary
underflows of dirtied pages counters on zone/bdi and current->nr_dirtied.

Signed-off-by: Konstantin Khebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index fb71e9d..6a73e47 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2168,9 +2168,12 @@
  */
 int redirty_page_for_writepage(struct writeback_control *wbc, struct page *page)
 {
+	int ret;
+
 	wbc->pages_skipped++;
+	ret = __set_page_dirty_nobuffers(page);
 	account_page_redirty(page);
-	return __set_page_dirty_nobuffers(page);
+	return ret;
 }
 EXPORT_SYMBOL(redirty_page_for_writepage);