From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f70.google.com (mail-pa0-f70.google.com [209.85.220.70]) by kanga.kvack.org (Postfix) with ESMTP id 86A846B007E for ; Mon, 25 Apr 2016 04:31:19 -0400 (EDT) Received: by mail-pa0-f70.google.com with SMTP id dx6so261586193pad.0 for ; Mon, 25 Apr 2016 01:31:19 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id u86si5506923pfa.250.2016.04.25.01.31.18 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Apr 2016 01:31:18 -0700 (PDT) Date: Mon, 25 Apr 2016 01:31:14 -0700 From: "hch@infradead.org" Subject: Re: [PATCH v2 5/5] dax: handle media errors in dax_do_io Message-ID: <20160425083114.GA27556@infradead.org> References: <1459303190-20072-1-git-send-email-vishal.l.verma@intel.com> <1459303190-20072-6-git-send-email-vishal.l.verma@intel.com> <20160420205923.GA24797@infradead.org> <1461434916.3695.7.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1461434916.3695.7.camel@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Verma, Vishal L" Cc: "hch@infradead.org" , "jmoyer@redhat.com" , "axboe@fb.com" , "jack@suse.cz" , "linux-nvdimm@ml01.01.org" , "david@fromorbit.com" , "linux-kernel@vger.kernel.org" , "xfs@oss.sgi.com" , "linux-block@vger.kernel.org" , "linux-mm@kvack.org" , "Wilcox, Matthew R" , "linux-fsdevel@vger.kernel.org" , "akpm@linux-foundation.org" , "linux-ext4@vger.kernel.org" , "viro@zeniv.linux.org.uk" On Sat, Apr 23, 2016 at 06:08:37PM +0000, Verma, Vishal L wrote: > direct_IO might fail with -EINVAL due to misalignment, or -ENOMEM due > to some allocation failing, and I thought we should return the original > -EIO in such cases so that the application doesn't lose the information > that the bad block is actually causing the error. EINVAL is a concern here. Not due to the right error reported, but because it means your current scheme is fundamentally broken - we need to support I/O at any alignment for DAX I/O, and not fail due to alignbment concernes for a highly specific degraded case. I think this whole series need to go back to the drawing board as I don't think it can actually rely on using direct I/O as the EIO fallback. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org