Re: [PATCH v2 6/8] vfs: copy_file_range should update file timestamps

Darrick J. Wong
2019-05-28T16:30:59Z

On Sun, May 26, 2019 at 09:10:57AM +0300, Amir Goldstein wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Timestamps are not updated right now, so programs looking for
> timestamp updates for file modifications (like rsync) will not
> detect that files have changed. We are also accessing the source
> data when doing a copy (but not when cloning) so we need to update
> atime on the source file as well.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
> fs/read_write.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/fs/read_write.c b/fs/read_write.c
> index e16bcafc0da2..4b23a86aacd9 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -1576,6 +1576,16 @@ int generic_copy_file_range_prep(struct file *file_in, struct file *file_out)
>
> WARN_ON_ONCE(!inode_is_locked(file_inode(file_out)));
>
> + /* Update source timestamps, because we are accessing file data */
> + file_accessed(file_in);
> +
> + /* Update destination timestamps, since we can alter file contents. */
> + if (!(file_out->f_mode & FMODE_NOCMTIME)) {
> + ret = file_update_time(file_out);
> + if (ret)
> + return ret;
> + }
> +
> /*
> * Clear the security bits if the process is not being run by root.
> * This keeps people from modifying setuid and setgid binaries.

Should the file_update_time and file_remove_privs calls be factored into
a separate small function to be called by generic_{copy,remap}_range_prep?

Looks ok otherwise,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> --
> 2.17.1
>