From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f198.google.com (mail-qk0-f198.google.com [209.85.220.198]) by kanga.kvack.org (Postfix) with ESMTP id 33E6F6B007E for ; Mon, 25 Apr 2016 11:32:13 -0400 (EDT) Received: by mail-qk0-f198.google.com with SMTP id n83so279180378qkn.0 for ; Mon, 25 Apr 2016 08:32:13 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id c70si5759321qka.36.2016.04.25.08.32.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Apr 2016 08:32:12 -0700 (PDT) From: Jeff Moyer Subject: Re: [PATCH v2 5/5] dax: handle media errors in dax_do_io 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> <20160425083114.GA27556@infradead.org> Date: Mon, 25 Apr 2016 11:32:08 -0400 In-Reply-To: <20160425083114.GA27556@infradead.org> (hch@infradead.org's message of "Mon, 25 Apr 2016 01:31:14 -0700") Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: "hch@infradead.org" Cc: "Verma, Vishal L" , "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" "hch@infradead.org" writes: > 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. The only callers of dax_do_io are direct_IO methods. Cheers, Jeff -- 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