Use deactivate_locked_super

Found by Al Viro.

Signed-off-by: Joern Engel <[e-mail]>

fs/logfs/super.c

···
 	return 0;
 
 err1:
-	up_write(&sb->s_umount);
-	deactivate_super(sb);
+	deactivate_locked_super(sb);
 	return err;
 err0:
 	kfree(super);