vfs: clean up vfs_rename_dir

Simplify control flow through vfs_rename_dir.
Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

@@ -2963,7 +2963,7 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
 			  struct inode *new_dir, struct dentry *new_dentry)
 {
 	int error = 0;
-	struct inode *target;
+	struct inode *target = new_dentry->d_inode;
 
 	/*
 	 * If we are going to change the parent - check write permissions,
@@ -2979,20 +2979,24 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
 	if (error)
 		return error;
 
-	target = new_dentry->d_inode;
 	if (target)
 		mutex_lock(&target->i_mutex);
-	if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry))
-		error = -EBUSY;
-	else
-		error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
+
+	error = -EBUSY;
+	if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry))
+		goto out;
+
+	error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
+	if (error)
+		goto out;
+
 	if (target) {
-		if (!error) {
-			target->i_flags |= S_DEAD;
-			dont_mount(new_dentry);
-		}
-		mutex_unlock(&target->i_mutex);
+		target->i_flags |= S_DEAD;
+		dont_mount(new_dentry);
 	}
+out:
+	if (target)
+		mutex_unlock(&target->i_mutex);
 	if (!error)
 		if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
 			d_move(old_dentry,new_dentry);