writeback: bdi_writeback_task() must set task state before calling schedule()

Calling schedule without setting the task state to non-running will
return immediately, so ensure that we set it properly and check our
sleep conditions after doing so.

This is a fixup for commit 69b62d01.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 76f546d56a646d0eceb6b6147af097e00aaa1e01..437a7431b4ea6e0ac7fface79d2029d3bc9aaf27 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -978,8 +978,13 @@ int bdi_writeback_task(struct bdi_writeback *wb)
                if (dirty_writeback_interval) {
                        wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10);
                        schedule_timeout_interruptible(wait_jiffies);
-               } else
-                       schedule();
+               } else {
+                       set_current_state(TASK_INTERRUPTIBLE);
+                       if (list_empty_careful(&wb->bdi->work_list) &&
+                           !kthread_should_stop())
+                               schedule();
+                       __set_current_state(TASK_RUNNING);
+               }
 
                try_to_freeze();
        }