From 4aea99c29d04c73030952743329e26c5339da51e Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 5 Nov 2013 16:55:45 +1100 Subject: [PATCH] writeback-do-not-sync-data-dirtied-after-sync-start-fix-2.txt On Wed 09-10-13 14:21:25, Andrew Morton wrote: > On Wed, 9 Oct 2013 17:03:25 +0200 Jan Kara wrote: > > > From: Jan Kara > > Date: Wed, 9 Oct 2013 15:41:50 +0200 > > Subject: [PATCH] writeback: Use older_than_this_is_set instead of magic > > older_than_this == 0 > > > > Currently we use 0 as a special value of work->older_than_this to > > indicate that wb_writeback() should set work->older_that_this to current > > time. This works but it is a bit magic. So use a special flag in > > work_struct for that. > > OK. > > > - if (!work->older_than_this) > > + if (!work->older_than_this_is_set) > > work->older_than_this = jiffies; > > It would be logical although presumably unneeded to set > older_than_this_is_set here? Yes. Updated. > > Also fixup writeback from workqueue rescuer to include all inodes. > > There's nothing in the patch which matches this sentence? The sentence is about the hunk below. writeback_inodes_wb() is special in that it directly calls queue_io() (everything else goes through wb_writeback()) and my previous patch thus resulted in using 0 as an older_than_this value => likely we wouldn't queue any inodes for writeback. I've added WARN_ON_ONCE into move_expired_inodes() to increase a chance of catching such mistakes in future (although in this particular case it wouldn't really help because writeback_inodes_wb() gets hardly ever called). Currently we use 0 as a special value of work->older_than_this to indicate that wb_writeback() should set work->older_that_this to current time. This works but it is a bit magic. So use a special flag in work_struct for that. Also fixup writeback from workqueue rescuer (writeback_inodes_wb()) to include all inodes. Currently it would use 0 as an older_than_this value thus queue_io() would likely not queue any inodes for writeback. Signed-off-by: Jan Kara Cc: Fengguang Wu Cc: Dave Chinner Signed-off-by: Andrew Morton --- 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 65e66caec76f..ba332d2c596a 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -251,6 +251,7 @@ static int move_expired_inodes(struct list_head *delaying_queue, int do_sb_sort = 0; int moved = 0; + WARN_ON_ONCE(!work->older_than_this_is_set); while (!list_empty(delaying_queue)) { inode = wb_inode(delaying_queue->prev); if (inode_dirtied_after(inode, work->older_than_this)) @@ -800,8 +801,10 @@ static long wb_writeback(struct bdi_writeback *wb, struct inode *inode; long progress; - if (!work->older_than_this_is_set) + if (!work->older_than_this_is_set) { work->older_than_this = jiffies; + work->older_than_this_is_set = 1; + } spin_lock(&wb->list_lock); for (;;) { -- 2.39.5