Btrfs: cleanup unnecessary assignment when cleaning up all the residual transaction

When we umount a fs with serious errors, we will invoke btrfs_cleanup_transactions()
to clean up the residual transaction. At this time, It is impossible to start a new
transaction, so we needn't assign trans_no_join to 1, and also needn't clear running
transaction every time we destroy a residual transaction.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

fs/btrfs/disk-io.c

@@ -3994,7 +3994,7 @@ static int btrfs_cleanup_transaction(struct btrfs_root *root)
 
 	spin_lock(&root->fs_info->trans_lock);
 	list_splice_init(&root->fs_info->trans_list, &list);
-	root->fs_info->trans_no_join = 1;
+	root->fs_info->running_transaction = NULL;
 	spin_unlock(&root->fs_info->trans_lock);
 
 	while (!list_empty(&list)) {
@@ -4030,10 +4030,6 @@ static int btrfs_cleanup_transaction(struct btrfs_root *root)
 
 		btrfs_destroy_all_delalloc_inodes(root->fs_info);
 
-		spin_lock(&root->fs_info->trans_lock);
-		root->fs_info->running_transaction = NULL;
-		spin_unlock(&root->fs_info->trans_lock);
-
 		btrfs_destroy_marked_extents(root, &t->dirty_pages,
 					     EXTENT_DIRTY);
 
@@ -4046,9 +4042,6 @@ static int btrfs_cleanup_transaction(struct btrfs_root *root)
 		kmem_cache_free(btrfs_transaction_cachep, t);
 	}
 
-	spin_lock(&root->fs_info->trans_lock);
-	root->fs_info->trans_no_join = 0;
-	spin_unlock(&root->fs_info->trans_lock);
 	mutex_unlock(&root->fs_info->transaction_kthread_mutex);
 
 	return 0;