linux-kernel - [RFC PATCH 3/3] xfs: mark the inode for high-res timestamp update in getattr

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Message-Id: <20230411142708.62475-4-jlayton@kernel.org>
Date:   Tue, 11 Apr 2023 10:27:08 -0400
From:   Jeff Layton <jlayton@...nel.org>
To:     Alexander Viro <viro@...iv.linux.org.uk>,
        Christian Brauner <brauner@...nel.org>,
        "Darrick J. Wong" <djwong@...nel.org>,
        Hugh Dickins <hughd@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-xfs@...r.kernel.org, linux-mm@...ck.org
Subject: [RFC PATCH 3/3] xfs: mark the inode for high-res timestamp update in getattr

When the mtime or ctime is being queried via getattr, ensure that we
mark the inode for a high-res timestamp update on the next pass. Also,
switch to current_cmtime for other c/mtime updates.

With this change, we're better off having the NFS server just ignore
the i_version field and have it use the ctime instead, so clear the
STATX_CHANGE_COOKIE flag in the result mask in ->getattr.

Signed-off-by: Jeff Layton <jlayton@...nel.org>
---
 fs/xfs/libxfs/xfs_trans_inode.c |  2 +-
 fs/xfs/xfs_acl.c                |  2 +-
 fs/xfs/xfs_inode.c              |  2 +-
 fs/xfs/xfs_iops.c               | 15 ++++++++++++---
 4 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_trans_inode.c b/fs/xfs/libxfs/xfs_trans_inode.c
index 8b5547073379..9ad7c229c617 100644
--- a/fs/xfs/libxfs/xfs_trans_inode.c
+++ b/fs/xfs/libxfs/xfs_trans_inode.c
@@ -63,7 +63,7 @@ xfs_trans_ichgtime(
 	ASSERT(tp);
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 
-	tv = current_time(inode);
+	tv = current_cmtime(inode);
 
 	if (flags & XFS_ICHGTIME_MOD)
 		inode->i_mtime = tv;
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index 791db7d9c849..461adc58cf8c 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -233,7 +233,7 @@ xfs_acl_set_mode(
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 	inode->i_mode = mode;
-	inode->i_ctime = current_time(inode);
+	inode->i_ctime = current_cmtime(inode);
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
 	if (xfs_has_wsync(mp))
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 5808abab786c..80f9d731e261 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -843,7 +843,7 @@ xfs_init_new_inode(
 	ip->i_df.if_nextents = 0;
 	ASSERT(ip->i_nblocks == 0);
 
-	tv = current_time(inode);
+	tv = current_cmtime(inode);
 	inode->i_mtime = tv;
 	inode->i_atime = tv;
 	inode->i_ctime = tv;
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 24718adb3c16..a0b07f90e16c 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -565,6 +565,15 @@ xfs_vn_getattr(
 	if (xfs_is_shutdown(mp))
 		return -EIO;
 
+	/*
+	 * XFS uses the i_version infrastructure to track any change to
+	 * the inode, including atime updates. This means that the i_version
+	 * returned by getattr doesn't conform to what the callers expect.
+	 * Clear it here so that nfsd will fake up a change cookie from the
+	 * ctime instead.
+	 */
+	stat->result_mask &= ~STATX_CHANGE_COOKIE;
+
 	stat->size = XFS_ISIZE(ip);
 	stat->dev = inode->i_sb->s_dev;
 	stat->mode = inode->i_mode;
@@ -573,8 +582,8 @@ xfs_vn_getattr(
 	stat->gid = vfsgid_into_kgid(vfsgid);
 	stat->ino = ip->i_ino;
 	stat->atime = inode->i_atime;
-	stat->mtime = inode->i_mtime;
-	stat->ctime = inode->i_ctime;
+	if (request_mask & (STATX_CTIME|STATX_MTIME))
+		fill_cmtime_and_mark(inode, stat);
 	stat->blocks = XFS_FSB_TO_BB(mp, ip->i_nblocks + ip->i_delayed_blks);
 
 	if (xfs_has_v3inodes(mp)) {
@@ -917,7 +926,7 @@ xfs_setattr_size(
 	if (newsize != oldsize &&
 	    !(iattr->ia_valid & (ATTR_CTIME | ATTR_MTIME))) {
 		iattr->ia_ctime = iattr->ia_mtime =
-			current_time(inode);
+			current_cmtime(inode);
 		iattr->ia_valid |= ATTR_CTIME | ATTR_MTIME;
 	}
 
-- 
2.39.2