[PATCH 2/2] btrfs: swap free() and trace point in run_ordered_work()

From: Sebastian Andrzej Siewior
Date: Wed Dec 14 2016 - 09:06:12 EST

The previous patch removed a trace point due to a use after free problem
with tracing enabled. While looking at the backtrace it took me a while
to find the right spot. While doing so I noticed that this trace point
could be used after one of two clean-up functions were invoked:
- run_one_async_free()
- async_cow_free()

Both of them free the `work' item so a later use in the tracepoint is
not possible.
This patch swaps the order so we first have the trace point and then
free the struct.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
fs/btrfs/async-thread.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index d0dfc3d2e199..6f4631bf74f8 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -288,8 +288,8 @@ static void run_ordered_work(struct __btrfs_workqueue *wq)
* we don't want to call the ordered free functions
* with the lock held though
- work->ordered_free(work);
+ work->ordered_free(work);
spin_unlock_irqrestore(lock, flags);