From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from g1t5424.austin.hp.com ([15.216.225.54]:52578 "EHLO g1t5424.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754870AbcEBSvy (ORCPT ); Mon, 2 May 2016 14:51:54 -0400 From: Toshi Kani To: dan.j.williams@intel.com, jack@suse.cz, david@fromorbit.com Cc: hch@infradead.org, boaz@plexistor.com, tytso@mit.edu, adilger.kernel@dilger.ca, ross.zwisler@linux.intel.com, toshi.kani@hpe.com, micah.parrish@hpe.com, linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/3] ext4: Add alignment check for DAX mount Date: Mon, 2 May 2016 12:42:56 -0600 Message-Id: <1462214578-27122-2-git-send-email-toshi.kani@hpe.com> In-Reply-To: <1462214578-27122-1-git-send-email-toshi.kani@hpe.com> References: <1462214578-27122-1-git-send-email-toshi.kani@hpe.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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. Call bdev_direct_access to check the alignment 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 Cc: Christoph Hellwig Cc: Boaz Harrosh --- fs/ext4/super.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 304c712..51ac78e 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3416,14 +3416,30 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) } if (sbi->s_mount_opt & EXT4_MOUNT_DAX) { + struct blk_dax_ctl dax = { + .sector = 0, + .size = PAGE_SIZE, + }; if (blocksize != PAGE_SIZE) { ext4_msg(sb, KERN_ERR, "error: unsupported blocksize for dax"); goto failed_mount; } - if (!sb->s_bdev->bd_disk->fops->direct_access) { - ext4_msg(sb, KERN_ERR, + err = bdev_direct_access(sb->s_bdev, &dax); + if (err < 0) { + switch (err) { + case -EOPNOTSUPP: + ext4_msg(sb, KERN_ERR, "error: device does not support dax"); + break; + case -EINVAL: + ext4_msg(sb, KERN_ERR, + "error: unaligned partition for dax"); + break; + default: + ext4_msg(sb, KERN_ERR, + "error: dax access failed (%d)", err); + } goto failed_mount; } }