btrfs: simplify mutex unlocking code in btrfs_commit_transaction

No functional change rearrange the mutex_unlock.
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
[ edit subject ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/transaction.c

@@ -2265,16 +2265,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
 	}
 
 	ret = write_all_supers(fs_info, 0);
-	if (ret) {
-		mutex_unlock(&fs_info->tree_log_mutex);
-		goto scrub_continue;
-	}
-
 	/*
 	 * the super is written, we can safely allow the tree-loggers
 	 * to go about their business
 	 */
 	mutex_unlock(&fs_info->tree_log_mutex);
+	if (ret)
+		goto scrub_continue;
 
 	btrfs_finish_extent_commit(trans, fs_info);