From patchwork Wed Feb 17 03:34:14 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ross Zwisler X-Patchwork-Id: 8334051 Return-Path: X-Original-To: patchwork-linux-block@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 9D8D69FD6F for ; Wed, 17 Feb 2016 03:36:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B910F202FE for ; Wed, 17 Feb 2016 03:36:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BBD9A20256 for ; Wed, 17 Feb 2016 03:36:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965111AbcBQDfC (ORCPT ); Tue, 16 Feb 2016 22:35:02 -0500 Received: from mga01.intel.com ([192.55.52.88]:7996 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965094AbcBQDfA (ORCPT ); Tue, 16 Feb 2016 22:35:00 -0500 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 16 Feb 2016 19:34:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,458,1449561600"; d="scan'208";a="916486830" Received: from rzwisler-desk.amr.corp.intel.com (HELO phyrexia.intel.com) ([10.254.20.43]) by fmsmga002.fm.intel.com with ESMTP; 16 Feb 2016 19:34:35 -0800 From: Ross Zwisler To: linux-kernel@vger.kernel.org Cc: Dan Williams , "J. Bruce Fields" , "Theodore Ts'o" , Alexander Viro , Andreas Dilger , Andrew Morton , Dave Chinner , Jan Kara , Jeff Layton , Jens Axboe , Matthew Wilcox , linux-block@vger.kernel.org, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org, xfs@oss.sgi.com, Jan Kara , Jens Axboe , Matthew Wilcox , Al Viro , Ross Zwisler Subject: [PATCH v3 1/6] block: disable block device DAX by default Date: Tue, 16 Feb 2016 20:34:14 -0700 Message-Id: <1455680059-20126-2-git-send-email-ross.zwisler@linux.intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1455680059-20126-1-git-send-email-ross.zwisler@linux.intel.com> References: <1455680059-20126-1-git-send-email-ross.zwisler@linux.intel.com> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Spam-Status: No, score=-6.9 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: Dan Williams The recent *sync enabling discovered that we are inserting into the block_device pagecache counter to the expectations of the dirty data tracking for dax mappings. This can lead to data corruption. We want to support DAX for block devices eventually, but it requires wider changes to properly manage the pagecache. [] dump_stack+0x85/0xc2 [] dax_writeback_mapping_range+0x60/0xe0 [] blkdev_writepages+0x3f/0x50 [] do_writepages+0x21/0x30 [] __filemap_fdatawrite_range+0xc6/0x100 [] filemap_write_and_wait+0x4a/0xa0 [] set_blocksize+0x70/0xd0 [] sb_set_blocksize+0x1d/0x50 [] ext4_fill_super+0x75b/0x3360 [] ? vsnprintf+0x201/0x4c0 [] ? snprintf+0x49/0x60 [] mount_bdev+0x180/0x1b0 [] ? ext4_calculate_overhead+0x370/0x370 [] ext4_mount+0x15/0x20 [] mount_fs+0x38/0x170 Mark the support broken so its disabled by default, but otherwise still available for testing. Cc: Jan Kara Cc: Jens Axboe Cc: Matthew Wilcox Cc: Al Viro Reported-by: Ross Zwisler Suggested-by: Dave Chinner Signed-off-by: Dan Williams Signed-off-by: Ross Zwisler Reviewed-by: Jan Kara --- block/Kconfig | 13 +++++++++++++ fs/block_dev.c | 6 +++++- 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/block/Kconfig b/block/Kconfig index 161491d..0363cd7 100644 --- a/block/Kconfig +++ b/block/Kconfig @@ -88,6 +88,19 @@ config BLK_DEV_INTEGRITY T10/SCSI Data Integrity Field or the T13/ATA External Path Protection. If in doubt, say N. +config BLK_DEV_DAX + bool "Block device DAX support" + depends on FS_DAX + depends on BROKEN + help + When DAX support is available (CONFIG_FS_DAX) raw block + devices can also support direct userspace access to the + storage capacity via MMAP(2) similar to a file on a + DAX-enabled filesystem. However, the DAX I/O-path disables + some standard I/O-statistics, and the MMAP(2) path has some + operational differences due to bypassing the page + cache. If in doubt, say N. + config BLK_DEV_THROTTLING bool "Block layer bio throttling support" depends on BLK_CGROUP=y diff --git a/fs/block_dev.c b/fs/block_dev.c index 39b3a17..31c6d10 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1201,7 +1201,11 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) bdev->bd_disk = disk; bdev->bd_queue = disk->queue; bdev->bd_contains = bdev; - bdev->bd_inode->i_flags = disk->fops->direct_access ? S_DAX : 0; + if (IS_ENABLED(CONFIG_BLK_DEV_DAX) && disk->fops->direct_access) + bdev->bd_inode->i_flags = S_DAX; + else + bdev->bd_inode->i_flags = 0; + if (!partno) { ret = -ENXIO; bdev->bd_part = disk_get_part(disk, partno);