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GET /api/patches/810302/?format=api
{ "id": 810302, "url": "http://patchwork.ozlabs.org/api/patches/810302/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-ext4/patch/20170905223541.20594-3-ross.zwisler@linux.intel.com/", "project": { "id": 8, "url": "http://patchwork.ozlabs.org/api/projects/8/?format=api", "name": "Linux ext4 filesystem development", "link_name": "linux-ext4", "list_id": "linux-ext4.vger.kernel.org", "list_email": "linux-ext4@vger.kernel.org", "web_url": null, "scm_url": null, "webscm_url": null, "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20170905223541.20594-3-ross.zwisler@linux.intel.com>", "list_archive_url": null, "date": "2017-09-05T22:35:34", "name": "[2/9] xfs: always use DAX if mount option is used", "commit_ref": null, "pull_url": null, "state": "new", "archived": true, "hash": "2c2d1c05f09c7512f0e79d55e591ace0fb075834", "submitter": { "id": 46514, "url": "http://patchwork.ozlabs.org/api/people/46514/?format=api", "name": "Ross Zwisler", "email": "ross.zwisler@linux.intel.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linux-ext4/patch/20170905223541.20594-3-ross.zwisler@linux.intel.com/mbox/", "series": [ { "id": 1660, "url": "http://patchwork.ozlabs.org/api/series/1660/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-ext4/list/?series=1660", "date": "2017-09-05T22:35:36", "name": "add ext4 per-inode DAX flag", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/1660/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/810302/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/810302/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<linux-ext4-owner@vger.kernel.org>", "X-Original-To": "patchwork-incoming@ozlabs.org", "Delivered-To": "patchwork-incoming@ozlabs.org", "Authentication-Results": "ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=linux-ext4-owner@vger.kernel.org;\n\treceiver=<UNKNOWN>)", "Received": [ "from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xn1lw51XNz9sP3\n\tfor <patchwork-incoming@ozlabs.org>;\n\tWed, 6 Sep 2017 08:36:28 +1000 (AEST)", "(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1753751AbdIEWg0 (ORCPT <rfc822;patchwork-incoming@ozlabs.org>);\n\tTue, 5 Sep 2017 18:36:26 -0400", "from mga01.intel.com ([192.55.52.88]:63245 \"EHLO mga01.intel.com\"\n\trhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP\n\tid S1752834AbdIEWgR (ORCPT <rfc822;linux-ext4@vger.kernel.org>);\n\tTue, 5 Sep 2017 18:36:17 -0400", "from fmsmga004.fm.intel.com ([10.253.24.48])\n\tby fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384;\n\t05 Sep 2017 15:36:15 -0700", "from theros.lm.intel.com ([10.232.112.77])\n\tby fmsmga004.fm.intel.com with ESMTP; 05 Sep 2017 15:36:14 -0700" ], "X-ExtLoop1": "1", "X-IronPort-AV": "E=Sophos;i=\"5.41,481,1498546800\"; d=\"scan'208\";a=\"308314868\"", "From": "Ross Zwisler <ross.zwisler@linux.intel.com>", "To": "Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org", "Cc": "Ross Zwisler <ross.zwisler@linux.intel.com>,\n\t\"Darrick J. Wong\" <darrick.wong@oracle.com>,\n\t\"Theodore Ts'o\" <tytso@mit.edu>,\n\tAndreas Dilger <adilger.kernel@dilger.ca>,\n\tChristoph Hellwig <hch@lst.de>, Dan Williams <dan.j.williams@intel.com>,\n\tDave Chinner <david@fromorbit.com>, Jan Kara <jack@suse.cz>,\n\tlinux-ext4@vger.kernel.org, linux-nvdimm@lists.01.org,\n\tlinux-xfs@vger.kernel.org, stable@vger.kernel.org", "Subject": "[PATCH 2/9] xfs: always use DAX if mount option is used", "Date": "Tue, 5 Sep 2017 16:35:34 -0600", "Message-Id": "<20170905223541.20594-3-ross.zwisler@linux.intel.com>", "X-Mailer": "git-send-email 2.9.5", "In-Reply-To": "<20170905223541.20594-1-ross.zwisler@linux.intel.com>", "References": "<20170905223541.20594-1-ross.zwisler@linux.intel.com>", "Sender": "linux-ext4-owner@vger.kernel.org", "Precedence": "bulk", "List-ID": "<linux-ext4.vger.kernel.org>", "X-Mailing-List": "linux-ext4@vger.kernel.org" }, "content": "The current code has an issue where the user can't reliably tell whether or\nnot DAX is being used to service page faults and I/O when the DAX mount\noption is used. In this case each inode within the mounted filesystem\nstarts with S_DAX set due to the mount option, but it can be cleared if\nsomeone touches the individual inode flag.\n\nFor example:\n\n # mount | grep dax\n /dev/pmem0 on /mnt type xfs\n (rw,relatime,seclabel,attr2,dax,inode64,sunit=4096,swidth=4096,noquota)\n\n # touch /mnt/a /mnt/b # both files currently use DAX\n\n # xfs_io -c \"lsattr\" /mnt/* # neither has the DAX inode option set\n ----------e----- /mnt/a\n ----------e----- /mnt/b\n\n # xfs_io -c \"chattr -x\" /mnt/a # this clears S_DAX for /mnt/a\n\n # xfs_io -c \"lsattr\" /mnt/*\n ----------e----- /mnt/a\n ----------e----- /mnt/b\n\nWe end up with both /mnt/a and /mnt/b looking identical from the point of\nview of the mount option and from lsattr, but one is using DAX and the\nother is not.\n\nFix this by always doing DAX I/O when either the mount option is set or\nwhen the DAX inode flag is set. This means that DAX will always be used\nfor all inodes on a filesystem mounted with -o dax, making the usage\nreliable and detectable.\n\nSigned-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>\nCC: stable@vger.kernel.org\n---\n fs/xfs/xfs_ioctl.c | 11 +++++++++--\n 1 file changed, 9 insertions(+), 2 deletions(-)", "diff": "diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c\nindex 9c0c7a9..8155ddc 100644\n--- a/fs/xfs/xfs_ioctl.c\n+++ b/fs/xfs/xfs_ioctl.c\n@@ -1008,7 +1008,7 @@ xfs_diflags_to_linux(\n \t\tinode->i_flags |= S_NOATIME;\n \telse\n \t\tinode->i_flags &= ~S_NOATIME;\n-\tif (xflags & FS_XFLAG_DAX)\n+\tif ((xflags & FS_XFLAG_DAX) || (ip->i_mount->m_flags & XFS_MOUNT_DAX))\n \t\tinode->i_flags |= S_DAX;\n \telse\n \t\tinode->i_flags &= ~S_DAX;\n@@ -1091,7 +1091,14 @@ xfs_ioctl_setattr_dax_invalidate(\n \t\t\treturn -EINVAL;\n \t}\n \n-\t/* If the DAX state is not changing, we have nothing to do here. */\n+\t/*\n+\t * If the DAX state is not changing, we have nothing to do here. If\n+\t * the DAX mount option was used we will update the DAX inode flag as\n+\t * the user requested but we will continue to use DAX for I/O and page\n+\t * faults regardless of how the inode flag is set.\n+\t */\n+\tif (ip->i_mount->m_flags & XFS_MOUNT_DAX)\n+\t\treturn 0;\n \tif ((fa->fsx_xflags & FS_XFLAG_DAX) && IS_DAX(inode))\n \t\treturn 0;\n \tif (!(fa->fsx_xflags & FS_XFLAG_DAX) && !IS_DAX(inode))\n", "prefixes": [ "2/9" ] }