From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756204AbcCaI7E (ORCPT ); Thu, 31 Mar 2016 04:59:04 -0400 Received: from mx2.suse.de ([195.135.220.15]:41247 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750971AbcCaI67 (ORCPT ); Thu, 31 Mar 2016 04:58:59 -0400 Date: Thu, 31 Mar 2016 10:59:25 +0200 From: Jan Kara To: Ross Zwisler Cc: Jan Kara , "Theodore Ts'o" , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: block allocator issue with ext4+DAX Message-ID: <20160331085925.GC11041@quack.suse.cz> References: <20160330220129.GA9101@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160330220129.GA9101@linux.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 30-03-16 16:01:29, Ross Zwisler wrote: > I've hit an issue in my testing which I believe to be related to the ext4 > block allocator when using the DAX mount option. I originally found this > issue with the generic/102 xfstest, but have reduced it to the minimal > reproducer at the bottom of this email. I've been able to reproduce this with > both BRD and with PMEM as the underlying block device. > > For this test we're running in a very small filesystem, only 512 MiB. We > fallocate() 400 MiB of that space, unlink the file, then try and rewrite that > 400 MiB file one chunk at a time. > > What actually happens is that during the rewrite we run out of memory and the > DAX call to get_block() in dax_io() fails with -ENOSPC. Yes, I have already sent a fix for this bug here: http://www.spinics.net/lists/linux-ext4/msg51649.html Ted, can you please pick it up? Thanks! Honza -- Jan Kara SUSE Labs, CR