From mboxrd@z Thu Jan 1 00:00:00 1970 From: 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> References: <1435608152-6982-1-git-send-email-matthew.r.wilcox@intel.com> Cc: Matthew Wilcox To: linux-fsdevel@vger.kernel.org, Alexander Viro Return-path: 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 In-Reply-To: <1435608152-6982-1-git-send-email-matthew.r.wilcox@intel.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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 -- 2.1.4