From: Tejun Heo <tj@kernel.org>
Date: Fri, 22 May 2015 21:13:56 +0000 (-0400)
Subject: writeback: make wakeup_dirtytime_writeback() handle multiple bdi_writeback's
X-Git-Tag: firefly_0821_release~176^2~1570^2~43
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=001fe6f617b1a352ad29cc3643384b3d8141dc07;p=firefly-linux-kernel-4.4.55.git

writeback: make wakeup_dirtytime_writeback() handle multiple bdi_writeback's

wakeup_dirtytime_writeback() currently only starts writeback on the
root wb (bdi_writeback).  For cgroup writeback support, update the
function to check all wbs.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 508e10cc3fcd..8ae212e90ec3 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1260,9 +1260,12 @@ static void wakeup_dirtytime_writeback(struct work_struct *w)
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
-		if (list_empty(&bdi->wb.b_dirty_time))
-			continue;
-		wb_wakeup(&bdi->wb);
+		struct bdi_writeback *wb;
+		struct wb_iter iter;
+
+		bdi_for_each_wb(wb, bdi, &iter, 0)
+			if (!list_empty(&bdi->wb.b_dirty_time))
+				wb_wakeup(&bdi->wb);
 	}
 	rcu_read_unlock();
 	schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ);