Re: [PATCH 09/16] fs: exit early in generic_update_time when there is no work

Jeff Layton <[email protected]> Thu, 20 Nov 2025 08:32:33 -0500

Newsgroups	dev.linux.lists.gfs2,org.infradead.lists.linux-mtd,org.kernel.vger.io-uring,org.kernel.vger.linux-btrfs,org.kernel.vger.linux-fsdevel,org.kernel.vger.linux-kernel,org.kernel.vger.linux-nfs,org.kernel.vger.linux-unionfs,org.kernel.vger.linux-xfs
Message-ID	<[email protected]>

On Thu, 2025-11-20 at 07:47 +0100, Christoph Hellwig wrote:
> 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 <[email protected]>
> ---
>  fs/inode.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/inode.c b/fs/inode.c
> index 15a8b2cf78ef..cda78f76e1dd 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2110,6 +2110,9 @@ 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)

Reviewed-by: Jeff Layton <[email protected]>