2 files changed, 4 insertions, 1 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 8a5807d2fb9d..7d9d06ba184b 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -68,7 +68,7 @@ int nr_pdflush_threads;
  */
 int writeback_in_progress(struct backing_dev_info *bdi)
 {
-        return !list_empty(&bdi->work_list);
+        return test_bit(BDI_writeback_running, &bdi->state);
 }
 
 static void bdi_queue_work(struct backing_dev_info *bdi,
@@ -740,6 +740,7 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
         struct wb_writeback_work *work;
         long wrote = 0;
 
+        set_bit(BDI_writeback_running, &wb->bdi->state);
         while ((work = get_next_work_item(bdi)) != NULL) {
                 /*
                  * Override sync mode, in case we must wait for completion
@@ -766,6 +767,7 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
          * Check for periodic writeback, kupdated() style
          */
         wrote += wb_check_old_data_flush(wb);
+        clear_bit(BDI_writeback_running, &wb->bdi->state);
 
         return wrote;
 }
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 7628219e5386..35b00746c712 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -31,6 +31,7 @@ enum bdi_state {
         BDI_async_congested,    /* The async (write) queue is getting full */
         BDI_sync_congested,     /* The sync queue is getting full */
         BDI_registered,         /* bdi_register() was done */
+        BDI_writeback_running,  /* Writeback is in progress */
         BDI_unused,             /* Available bits start here */
 };