From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752307AbbGMPdt (ORCPT ); Mon, 13 Jul 2015 11:33:49 -0400 Received: from mga14.intel.com ([192.55.52.115]:28405 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751327AbbGMPds (ORCPT ); Mon, 13 Jul 2015 11:33:48 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,463,1432623600"; d="scan'208";a="523491876" Date: Mon, 13 Jul 2015 11:33:45 -0400 From: Matthew Wilcox To: Jan Kara Cc: Matthew Wilcox , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 07/10] dax: Add huge page fault support Message-ID: <20150713153345.GI13681@linux.intel.com> References: <1436560165-8943-1-git-send-email-matthew.r.wilcox@intel.com> <1436560165-8943-8-git-send-email-matthew.r.wilcox@intel.com> <20150713150500.GB17075@quack.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150713150500.GB17075@quack.suse.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 13, 2015 at 05:05:00PM +0200, Jan Kara wrote: > So if this is a writeable fault and we race with truncate, we can leave > stale blocks beyond i_size, can't we? Ah, looking at dax_insert_mapping() > this seems to be a documented quirk of DAX mmap code. Would be worth > mentioning here as well so that people don't wonder... Thanks! - /* Guard against a race with truncate */ + /* + * If a truncate happened while we were allocating blocks, we may + * leave blocks allocated to the file that are beyond EOF. We can't + * take i_mutex here, so just leave them hanging; they'll be freed + * when the file is deleted. + */ is what I'll commit.