Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753070AbcD2Us2 (ORCPT ); Fri, 29 Apr 2016 16:48:28 -0400 Received: from g1t5424.austin.hp.com ([15.216.225.54]:55595 "EHLO g1t5424.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753023AbcD2Us1 (ORCPT ); Fri, 29 Apr 2016 16:48:27 -0400 From: Toshi Kani To: dan.j.williams@intel.com, david@fromorbit.com, jack@suse.cz Cc: tytso@mit.edu, adilger.kernel@dilger.ca, ross.zwisler@linux.intel.com, toshi.kani@hpe.com, linux-nvdimm@ml01.01.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] ext4: Add alignment check for DAX mount Date: Fri, 29 Apr 2016 14:39:33 -0600 Message-Id: <1461962375-3720-2-git-send-email-toshi.kani@hpe.com> X-Mailer: git-send-email 2.5.5 In-Reply-To: <1461962375-3720-1-git-send-email-toshi.kani@hpe.com> References: <1461962375-3720-1-git-send-email-toshi.kani@hpe.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1220 Lines: 34 When a partition is not aligned by 4KB, mount -o dax succeeds, but any read/write access to the filesystem fails, except for metadata update. Add alignment check to ext4_fill_super() when -o dax is specified. Reported-by: Micah Parrish Signed-off-by: Toshi Kani Cc: "Theodore Ts'o" Cc: Andreas Dilger Cc: Jan Kara Cc: Dan Williams Cc: Ross Zwisler --- fs/ext4/super.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 304c712..90a8670 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3421,6 +3421,12 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) "error: unsupported blocksize for dax"); goto failed_mount; } + if (sb->s_bdev->bd_part->start_sect % (PAGE_SIZE / 512) || + sb->s_bdev->bd_part->nr_sects % (PAGE_SIZE / 512)) { + ext4_msg(sb, KERN_ERR, + "error: unaligned partition for dax"); + goto failed_mount; + } if (!sb->s_bdev->bd_disk->fops->direct_access) { ext4_msg(sb, KERN_ERR, "error: device does not support dax");