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From:   Jeff Layton <jlayton@kernel.org>
To:     "Darrick J . Wong" <djwong@kernel.org>
Cc:     linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-nfs@vger.kernel.org, linux-integrity@vger.kernel.org,
        Dave Chinner <david@fromorbit.com>, NeilBrown <neilb@suse.de>,
        Trond Myklebust <trondmy@hammerspace.com>,
        David Wysochanski <dwysocha@redhat.com>
Subject: [PATCH] xfs: don't bump the i_version on an atime update in xfs_vn_update_time
Date:   Fri, 19 Aug 2022 07:34:50 -0400
Message-Id: <20220819113450.11885-1-jlayton@kernel.org>
MIME-Version: 1.0
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Precedence: bulk

xfs will update the i_version when updating only the atime value, which
is not desirable for any of the current consumers of i_version. Doing so
leads to unnecessary cache invalidations on NFS and extra measurement
activity in IMA.

Add a new XFS_ILOG_NOIVER flag, and use that to indicate that the
transaction should not update the i_version. Set that value in
xfs_vn_update_time if we're only updating the atime.

Cc: Dave Chinner <david@fromorbit.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Trond Myklebust <trondmy@hammerspace.com>
Cc: David Wysochanski <dwysocha@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/xfs/libxfs/xfs_log_format.h  |  2 +-
 fs/xfs/libxfs/xfs_trans_inode.c |  2 +-
 fs/xfs/xfs_iops.c               | 10 +++++++---
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
index b351b9dc6561..866a4c5cf70c 100644
--- a/fs/xfs/libxfs/xfs_log_format.h
+++ b/fs/xfs/libxfs/xfs_log_format.h
@@ -323,7 +323,7 @@ struct xfs_inode_log_format_32 {
 #define	XFS_ILOG_ABROOT	0x100	/* log i_af.i_broot */
 #define XFS_ILOG_DOWNER	0x200	/* change the data fork owner on replay */
 #define XFS_ILOG_AOWNER	0x400	/* change the attr fork owner on replay */
-
+#define XFS_ILOG_NOIVER	0x800	/* don't bump i_version */
 
 /*
  * The timestamps are dirty, but not necessarily anything else in the inode
diff --git a/fs/xfs/libxfs/xfs_trans_inode.c b/fs/xfs/libxfs/xfs_trans_inode.c
index 8b5547073379..ffe6d296e7f9 100644
--- a/fs/xfs/libxfs/xfs_trans_inode.c
+++ b/fs/xfs/libxfs/xfs_trans_inode.c
@@ -126,7 +126,7 @@ xfs_trans_log_inode(
 	 * unconditionally.
 	 */
 	if (!test_and_set_bit(XFS_LI_DIRTY, &iip->ili_item.li_flags)) {
-		if (IS_I_VERSION(inode) &&
+		if (!(flags & XFS_ILOG_NOIVER) && IS_I_VERSION(inode) &&
 		    inode_maybe_inc_iversion(inode, flags & XFS_ILOG_CORE))
 			iversion_flags = XFS_ILOG_CORE;
 	}
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 45518b8c613c..54db85a43dfb 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1021,7 +1021,7 @@ xfs_vn_update_time(
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
-	int			log_flags = XFS_ILOG_TIMESTAMP;
+	int			log_flags = XFS_ILOG_TIMESTAMP|XFS_ILOG_NOIVER;
 	struct xfs_trans	*tp;
 	int			error;
 
@@ -1041,10 +1041,14 @@ xfs_vn_update_time(
 		return error;
 
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
-	if (flags & S_CTIME)
+	if (flags & S_CTIME) {
 		inode->i_ctime = *now;
-	if (flags & S_MTIME)
+		log_flags &= ~XFS_ILOG_NOIVER;
+	}
+	if (flags & S_MTIME) {
 		inode->i_mtime = *now;
+		log_flags &= ~XFS_ILOG_NOIVER;
+	}
 	if (flags & S_ATIME)
 		inode->i_atime = *now;
 
-- 
2.37.2