Re: git: 54d31cfb2789 - main - mount: document atime option

On Wed, Jan 24, 2024 at 11:56 AM Ed Maste <emaste@freebsd.org> wrote:
>
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> The branch main has been updated by emaste:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=54d31cfb278982ff8c2af97a13e40b1a3ebd838e
>
> commit 54d31cfb278982ff8c2af97a13e40b1a3ebd838e
> Author:     Ed Maste <emaste@FreeBSD.org>
> AuthorDate: 2024-01-24 16:26:23 +0000
> Commit:     Ed Maste <emaste@FreeBSD.org>
> CommitDate: 2024-01-24 19:55:54 +0000
>
>     mount: document atime option
>
>     atime is enabled by default, but may be specified explicitly so that any
>     future change in the default would not have an effect on a given mount.
>
>     Reviewed by:    olce, rgrimes
>     Sponsored by:   The FreeBSD Foundation
>     Differential Revision: https://reviews.freebsd.org/D43580
> ---
>  sbin/mount/mount.8 | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/sbin/mount/mount.8 b/sbin/mount/mount.8
> index 883e0bb5caf0..e8e604ba4088 100644
> --- a/sbin/mount/mount.8
> +++ b/sbin/mount/mount.8
> @@ -25,7 +25,7 @@
>  .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
>  .\" SUCH DAMAGE.
>  .\"
> -.Dd January 15, 2024
> +.Dd January 24, 2024
>  .Dt MOUNT 8
>  .Os
>  .Sh NAME
> @@ -155,6 +155,9 @@ For this reason, the
>  .Cm async
>  flag should be used sparingly, and only when some data recovery
>  mechanism is present.
> +.It Cm atime
> +Update the file access time when reading from a file.
> +This is the default.
I'll note that, for an NFS mount, atime is not implemented. I found
out recently when Mike Karels asked. The NFS client does not
do a Setattr/atime upon every read from the buffer cache. As such,
the behaviour w.r.t. atime is largely undefined (and ahs been for decades)
and depends on the NFS server's file system configuration.
(I don't know if a "works for most file systems, but not NFS" is needed here?

rick

>  .It Cm automounted
>  This flag indicates that the file system was mounted by
>  .Xr automountd 8 .