linux-kernel - [PATCH 02/14] fs: lift the FMODE_NOCMTIME check into file_update_time

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Message-ID: <20251114062642.1524837-3-hch@lst.de>
Date: Fri, 14 Nov 2025 07:26:05 +0100
From: Christoph Hellwig <hch@....de>
To: Christian Brauner <brauner@...nel.org>
Cc: Al Viro <viro@...iv.linux.org.uk>,
	David Sterba <dsterba@...e.com>,
	Jan Kara <jack@...e.cz>,
	Mike Marshall <hubcap@...ibond.com>,
	Martin Brandenburg <martin@...ibond.com>,
	Carlos Maiolino <cem@...nel.org>,
	Stefan Roesch <shr@...com>,
	Jeff Layton <jlayton@...nel.org>,
	linux-kernel@...r.kernel.org,
	linux-btrfs@...r.kernel.org,
	gfs2@...ts.linux.dev,
	io-uring@...r.kernel.org,
	devel@...ts.orangefs.org,
	linux-unionfs@...r.kernel.org,
	linux-mtd@...ts.infradead.org,
	linux-xfs@...r.kernel.org,
	linux-nfs@...r.kernel.org
Subject: [PATCH 02/14] fs: lift the FMODE_NOCMTIME check into file_update_time_flags

FMODE_NOCMTIME used to be just a hack for the legacy XFS handle-based
"invisible I/O", but commit e5e9b24ab8fa ("nfsd: freeze c/mtime updates
with outstanding WRITE_ATTRS delegation") started using it from
generic callers.

I'm not sure other file systems are actually read for this in general,
so the above commit should get a closer look, but for it to make any
sense, file_update_time needs to respect the flag.

Lift the check from file_modified_flags to file_update_time so that
users of file_update_time inherit the behavior and so that all the
checks are done in one place.

Fixes: e5e9b24ab8fa ("nfsd: freeze c/mtime updates with outstanding WRITE_ATTRS delegation")
Signed-off-by: Christoph Hellwig <hch@....de>
---
 fs/inode.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 4884ffa931e7..24dab63844db 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2320,6 +2320,8 @@ static int file_update_time_flags(struct file *file, unsigned int flags)
 	/* First try to exhaust all avenues to not sync */
 	if (IS_NOCMTIME(inode))
 		return 0;
+	if (unlikely(file->f_mode & FMODE_NOCMTIME))
+		return 0;
 
 	now = current_time(inode);
 
@@ -2391,8 +2393,6 @@ static int file_modified_flags(struct file *file, int flags)
 	ret = file_remove_privs_flags(file, flags);
 	if (ret)
 		return ret;
-	if (unlikely(file->f_mode & FMODE_NOCMTIME))
-		return 0;
 	return file_update_time_flags(file, flags);
 }
 
-- 
2.47.3