From: Jan Kara <jack@xxxxxxx> Background writeback and kupdate-style writeback are easily livelockable (from a definition of their target). This is inconvenient because it can make sync(1) stall forever waiting on its queued work to be finished. Fix the problem by interrupting background and kupdate writeback if there is some other work to do. We can return to them after completing all the queued work. Signed-off-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx> --- fs/fs-writeback.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- linux-next.orig/fs/fs-writeback.c 2010-09-13 13:58:47.000000000 +0800 +++ linux-next/fs/fs-writeback.c 2010-09-13 14:03:54.000000000 +0800 @@ -643,6 +643,14 @@ static long wb_writeback(struct bdi_writ break; /* + * Background writeout and kupdate-style writeback are + * easily livelockable. Stop them if there is other work + * to do so that e.g. sync can proceed. + */ + if ((work->for_background || work->for_kupdate) && + !list_empty(&wb->bdi->work_list)) + break; + /* * For background writeout, stop when we are below the * background dirty threshold */ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>