linux-kernel - [PATCH 08/14] fs: exit early in generic_update

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Message-ID: <20251114062642.1524837-9-hch@lst.de>
Date: Fri, 14 Nov 2025 07:26:11 +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 08/14] fs: exit early in generic_update_time when there is no work

Exit early if not attributes are to be updated, to avoid a spurious call
to __mark_inode_dirty which can turn into a fairly expensive no-op due to
the extra checks and locking.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 fs/inode.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/inode.c b/fs/inode.c
index 74e672dd90aa..57c458ee548d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2098,6 +2098,9 @@ int generic_update_time(struct inode *inode, int flags)
 	int updated = inode_update_timestamps(inode, flags);
 	int dirty_flags = 0;
 
+	if (!updated)
+		return 0;
+
 	if (updated & (S_ATIME|S_MTIME|S_CTIME))
 		dirty_flags = inode->i_sb->s_flags & SB_LAZYTIME ? I_DIRTY_TIME : I_DIRTY_SYNC;
 	if (updated & S_VERSION)
-- 
2.47.3