btrfs: cleanup extent_op handling

The cleanup_extent_op function actually would run the extent_op if it
needed running, which made the name sort of a misnomer.  Change it to
run_and_cleanup_extent_op, and move the actual cleanup work to
cleanup_extent_op so it can be used by check_ref_cleanup() in order to
unify the extent op handling.
Reviewed-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent-tree.c

@@ -2424,19 +2424,32 @@ static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_ref
 	btrfs_delayed_ref_unlock(head);
 }
 
-static int cleanup_extent_op(struct btrfs_trans_handle *trans,
-			     struct btrfs_delayed_ref_head *head)
+static struct btrfs_delayed_extent_op *cleanup_extent_op(
+				struct btrfs_delayed_ref_head *head)
 {
 	struct btrfs_delayed_extent_op *extent_op = head->extent_op;
-	int ret;
 
 	if (!extent_op)
-		return 0;
-	head->extent_op = NULL;
+		return NULL;
+
 	if (head->must_insert_reserved) {
+		head->extent_op = NULL;
 		btrfs_free_delayed_extent_op(extent_op);
-		return 0;
+		return NULL;
 	}
+	return extent_op;
+}
+
+static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,
+				     struct btrfs_delayed_ref_head *head)
+{
+	struct btrfs_delayed_extent_op *extent_op;
+	int ret;
+
+	extent_op = cleanup_extent_op(head);
+	if (!extent_op)
+		return 0;
+	head->extent_op = NULL;
 	spin_unlock(&head->lock);
 	ret = run_delayed_extent_op(trans, head, extent_op);
 	btrfs_free_delayed_extent_op(extent_op);
@@ -2488,7 +2501,7 @@ static int cleanup_ref_head(struct btrfs_trans_handle *trans,
 
 	delayed_refs = &trans->transaction->delayed_refs;
 
-	ret = cleanup_extent_op(trans, head);
+	ret = run_and_cleanup_extent_op(trans, head);
 	if (ret < 0) {
 		unselect_delayed_ref_head(delayed_refs, head);
 		btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
@@ -6980,12 +6993,8 @@ static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
 	if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
 		goto out;
 
-	if (head->extent_op) {
-		if (!head->must_insert_reserved)
-			goto out;
-		btrfs_free_delayed_extent_op(head->extent_op);
-		head->extent_op = NULL;
-	}
+	if (cleanup_extent_op(head) != NULL)
+		goto out;
 
 	/*
 	 * waiting for the lock here would deadlock.  If someone else has it