[PATCH 2/6] writeback: wb_start_writeback() should use WB_SYNC_ALL for WB_REASON_SYNC

From: Jens Axboe
Date: Tue Mar 22 2016 - 13:55:44 EST


If you call sync, the initial call to wakeup_flusher_threads() ends up
calling wb_start_writeback() with reason=WB_REASON_SYNC, but
wb_start_writeback() always uses WB_SYNC_NONE as the writeback mode.
Ensure that we use WB_SYNC_ALL for a sync operation.

Signed-off-by: Jens Axboe <axboe@xxxxxx>
---
fs/fs-writeback.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 5c46ed9f3e14..97a9e9987134 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -936,7 +936,10 @@ void wb_start_writeback(struct bdi_writeback *wb, long nr_pages,
return;
}

- work->sync_mode = WB_SYNC_NONE;
+ if (reason == WB_REASON_SYNC)
+ work->sync_mode = WB_SYNC_ALL;
+ else
+ work->sync_mode = WB_SYNC_NONE;
work->nr_pages = nr_pages;
work->range_cyclic = range_cyclic;
work->reason = reason;
--
2.4.1.168.g1ea28e1