From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f72.google.com (mail-it0-f72.google.com [209.85.214.72]) by kanga.kvack.org (Postfix) with ESMTP id F349A6B0038 for ; Thu, 15 Sep 2016 13:45:15 -0400 (EDT) Received: by mail-it0-f72.google.com with SMTP id o3so84984232ita.3 for ; Thu, 15 Sep 2016 10:45:15 -0700 (PDT) Received: from mail-oi0-x230.google.com (mail-oi0-x230.google.com. [2607:f8b0:4003:c06::230]) by mx.google.com with ESMTPS id 8si5092527otm.126.2016.09.15.10.44.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 15 Sep 2016 10:44:54 -0700 (PDT) Received: by mail-oi0-x230.google.com with SMTP id w11so80464116oia.2 for ; Thu, 15 Sep 2016 10:44:54 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20160915170942.GJ9314@birch.djwong.org> References: <147392246509.9873.17750323049785100997.stgit@dwillia2-desk3.amr.corp.intel.com> <147392247875.9873.4205533916442000884.stgit@dwillia2-desk3.amr.corp.intel.com> <20160915082615.GA9772@lst.de> <20160915170942.GJ9314@birch.djwong.org> From: Dan Williams Date: Thu, 15 Sep 2016 10:44:53 -0700 Message-ID: Subject: Re: [PATCH v2 2/3] mm, dax: add VM_DAX flag for DAX VMAs Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: "Darrick J. Wong" Cc: Christoph Hellwig , "linux-nvdimm@lists.01.org" , "linux-kernel@vger.kernel.org" , Nicholas Piggin , XFS Developers , Linux MM , linux-fsdevel On Thu, Sep 15, 2016 at 10:09 AM, Darrick J. Wong wrote: > On Thu, Sep 15, 2016 at 10:01:03AM -0700, Dan Williams wrote: >> On Thu, Sep 15, 2016 at 1:26 AM, Christoph Hellwig wrote: >> > On Wed, Sep 14, 2016 at 11:54:38PM -0700, Dan Williams wrote: >> >> The DAX property, page cache bypass, of a VMA is only detectable via the >> >> vma_is_dax() helper to check the S_DAX inode flag. However, this is >> >> only available internal to the kernel and is a property that userspace >> >> applications would like to interrogate. >> > >> > They have absolutely no business knowing such an implementation detail. >> >> Hasn't that train already left the station with FS_XFLAG_DAX? > > Seeing as FS_IOC_FSGETXATTR is a "generic" ioctl now, why not just > implement it for all the DAX fses and block devices? Aside from xflags, > the other fields are probably all zero for non-xfs (aside from project > quota id I guess). > > (Yeah, sort of awkward, I know...) It would solve the problem at hand, I'll take a look. -- 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