Btrfs: call the ordered free operation without any locks held

Each ordered operation has a free callback, and this was called with the
worker spinlock held.  Josef made the free callback also call iput,
which we can't do with the spinlock.

This drops the spinlock for the free operation and grabs it again before
moving through the rest of the list.  We'll circle back around to this
and find a cleaner way that doesn't bounce the lock around so much.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
cc: stable@kernel.org

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 42704149b72343f720af7844ec1c36a51da4140e..58b7d14b08ee1d47ec66a06243ee16f63854b676 100644 (file)
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -206,10 +206,17 @@ static noinline void run_ordered_completions(struct btrfs_workers *workers,
 
                work->ordered_func(work);
 
-               /* now take the lock again and call the freeing code */
+               /* now take the lock again and drop our item from the list */
                spin_lock(&workers->order_lock);
                list_del(&work->order_list);
+               spin_unlock(&workers->order_lock);
+
+               /*
+                * we don't want to call the ordered free functions
+                * with the lock held though
+                */
                work->ordered_free(work);
+               spin_lock(&workers->order_lock);
        }
 
        spin_unlock(&workers->order_lock);