From patchwork Mon Jun 29 20:02:28 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Wilcox, Matthew R" X-Patchwork-Id: 6691641 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 6DBEA9F1C1 for ; Mon, 29 Jun 2015 20:02:47 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A3021205BC for ; Mon, 29 Jun 2015 20:02:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B88B7205B8 for ; Mon, 29 Jun 2015 20:02:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752907AbbF2UCn (ORCPT ); Mon, 29 Jun 2015 16:02:43 -0400 Received: from mga09.intel.com ([134.134.136.24]:4752 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752919AbbF2UCm (ORCPT ); Mon, 29 Jun 2015 16:02:42 -0400 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga102.jf.intel.com with ESMTP; 29 Jun 2015 13:02:42 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,372,1432623600"; d="scan'208";a="752737036" Received: from trhope-mobl1.amr.corp.intel.com (HELO thog.int.wil.cx) ([10.252.192.243]) by fmsmga002.fm.intel.com with SMTP; 29 Jun 2015 13:02:41 -0700 Received: by thog.int.wil.cx (Postfix, from userid 1000) id BDE495F9DA; Mon, 29 Jun 2015 16:02:40 -0400 (EDT) From: Matthew Wilcox To: linux-fsdevel@vger.kernel.org, Alexander Viro Cc: Matthew Wilcox Subject: [PATCH 1/5] dax: Add block size note to documentation Date: Mon, 29 Jun 2015 16:02:28 -0400 Message-Id: <1435608152-6982-2-git-send-email-matthew.r.wilcox@intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1435608152-6982-1-git-send-email-matthew.r.wilcox@intel.com> References: <1435608152-6982-1-git-send-email-matthew.r.wilcox@intel.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Matthew Wilcox For block devices which are small enough, mkfs will default to creating a filesystem with block sizes smaller than page size. Signed-off-by: Matthew Wilcox --- Documentation/filesystems/dax.txt | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt index baf4111..7af2851 100644 --- a/Documentation/filesystems/dax.txt +++ b/Documentation/filesystems/dax.txt @@ -18,8 +18,10 @@ Usage ----- If you have a block device which supports DAX, you can make a filesystem -on it as usual. When mounting it, use the -o dax option manually -or add 'dax' to the options in /etc/fstab. +on it as usual. The DAX code currently only supports files with a block +size equal to your kernel's PAGE_SIZE, so you may need to specify a block +size when creating the filesystem. When mounting it, use the "-o dax" +option on the command line or add 'dax' to the options in /etc/fstab. Implementation Tips for Block Driver Writers