2 files changed, 8 insertions, 5 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index e3ab1e4dc442..f79f641de4ff 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1038,10 +1038,10 @@ void bdi_writeback_workfn(struct work_struct *work)
                 trace_writeback_pages_written(pages_written);
         }
 
-        if (!list_empty(&bdi->work_list) ||
-            (wb_has_dirty_io(wb) && dirty_writeback_interval))
-                queue_delayed_work(bdi_wq, &wb->dwork,
-                        msecs_to_jiffies(dirty_writeback_interval * 10));
+        if (!list_empty(&bdi->work_list))
+                mod_delayed_work(bdi_wq, &wb->dwork, 0);
+        else if (wb_has_dirty_io(wb) && dirty_writeback_interval)
+                bdi_wakeup_thread_delayed(bdi);
 
         current->flags &= ~PF_SWAPWRITE;
 }
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 502517492258..95e437435788 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -287,13 +287,16 @@ int bdi_has_dirty_io(struct backing_dev_info *bdi)
  * Note, we wouldn't bother setting up the timer, but this function is on the
  * fast-path (used by '__mark_inode_dirty()'), so we save few context switches
  * by delaying the wake-up.
+ *
+ * We have to be careful not to postpone flush work if it is scheduled for
+ * earlier. Thus we use queue_delayed_work().
  */
 void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi)
 {
         unsigned long timeout;
 
         timeout = msecs_to_jiffies(dirty_writeback_interval * 10);
-        mod_delayed_work(bdi_wq, &bdi->wb.dwork, timeout);
+        queue_delayed_work(bdi_wq, &bdi->wb.dwork, timeout);
 }
 
 /*