Revert "writeback: do not sync data dirtied after sync start"

This reverts commit c4a391b53a72d2df4ee97f96f78c1d5971b47489. Dave
Chinner <david@fromorbit.com> has reported the commit may cause some
inodes to be left out from sync(2). This is because we can call
redirty_tail() for some inode (which sets i_dirtied_when to current time)
after sync(2) has started or similarly requeue_inode() can set
i_dirtied_when to current time if writeback had to skip some pages. The
real problem is in the functions clobbering i_dirtied_when but fixing
that isn't trivial so revert is a safer choice for now.

CC: stable@vger.kernel.org # >= 3.13
Signed-off-by: Jan Kara <jack@suse.cz>

2 files changed, 4 insertions, 4 deletions

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index fc0e4320aa6d..021b8a319b9e 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -97,7 +97,7 @@ void writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
 int try_to_writeback_inodes_sb(struct super_block *, enum wb_reason reason);
 int try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
                                   enum wb_reason reason);
-void sync_inodes_sb(struct super_block *sb, unsigned long older_than_this);
+void sync_inodes_sb(struct super_block *);
 void wakeup_flusher_threads(long nr_pages, enum wb_reason reason);
 void inode_wait_for_writeback(struct inode *inode);
 
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index c7bbbe794e65..464ea82e10db 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -287,11 +287,11 @@ TRACE_EVENT(writeback_queue_io,
                 __field(int,            reason)
         ),
         TP_fast_assign(
-                unsigned long older_than_this = work->older_than_this;
+                unsigned long *older_than_this = work->older_than_this;
                 strncpy(__entry->name, dev_name(wb->bdi->dev), 32);
-                __entry->older  = older_than_this;
+                __entry->older  = older_than_this ?  *older_than_this : 0;
                 __entry->age    = older_than_this ?
-                                  (jiffies - older_than_this) * 1000 / HZ : -1;
+                                  (jiffies - *older_than_this) * 1000 / HZ : -1;
                 __entry->moved  = moved;
                 __entry->reason = work->reason;
         ),