Can't remove 'noatime' on mounted filesystem on CURRENT

[Scot Hetzel]

On 8/9/07, rodrigc at comcast.net <rodrigc at comcast.net> wrote:
> > The only way to get rid of noatime is to umount and remount the UFS
> filesystem.
>
> Hi,
>
> I have a patch pending for CURRENT which deals with this issue, but has not
> been
> approved by re@ yet.
>
> In the meantime, the workaround is to do:
>
> mount -u -o nonoatime
>
The work around works on UFS, but fails on ZFS.

I had to unmount the ZFS filesystem before it would allow me to set
noatime with mount again.  But it wouldn't allow me to unset noatime
with mount:

hp010# umount /usr/ports/distfiles
hp010# zfs mount -a
hp010# zfs get atime rootpool/usr/ports/distfiles ; mount | grep distfiles
NAME                          PROPERTY  VALUE                         SOURCE
rootpool/usr/ports/distfiles  atime     on                            default
rootpool/usr/ports/distfiles on /usr/ports/distfiles (zfs, local)
hp010# mount -u -o noatime /usr/ports/distfiles
hp010# zfs get atime rootpool/usr/ports/distfiles ; mount | grep distfiles
NAME                          PROPERTY  VALUE                         SOURCE
rootpool/usr/ports/distfiles  atime     off                           temporary
rootpool/usr/ports/distfiles on /usr/ports/distfiles (zfs, local, noatime)
hp010# mount -u -o nonoatime /usr/ports/distfiles
hp010# zfs get atime rootpool/usr/ports/distfiles ; mount | grep distfiles
NAME                          PROPERTY  VALUE                         SOURCE
rootpool/usr/ports/distfiles  atime     off                           temporary
rootpool/usr/ports/distfiles on /usr/ports/distfiles (zfs, local, noatime)
hp010# mount -u -o atime /usr/ports/distfiles
hp010# zfs get atime rootpool/usr/ports/distfiles ; mount | grep distfiles
NAME                          PROPERTY  VALUE                         SOURCE
rootpool/usr/ports/distfiles  atime     off                           temporary
rootpool/usr/ports/distfiles on /usr/ports/distfiles (zfs, local, noatime)

The only way to reset it is to use zfs inherit or zfs set:

hp010# zfs inherit -r atime rootpool/usr/ports/distfiles
hp010# zfs get atime rootpool/usr/ports/distfiles ; mount | grep distfiles
NAME                          PROPERTY  VALUE                         SOURCE
rootpool/usr/ports/distfiles  atime     on                            default
rootpool/usr/ports/distfiles on /usr/ports/distfiles (zfs, local)
hp010# mount -u -o nonoatime /usr/ports/distfiles
hp010# zfs get atime rootpool/usr/ports/distfiles ; mount | grep distfiles
NAME                          PROPERTY  VALUE                         SOURCE
rootpool/usr/ports/distfiles  atime     on                            default
rootpool/usr/ports/distfiles on /usr/ports/distfiles (zfs, local)
hp010# mount -u -o noatime /usr/ports/distfiles
hp010# zfs get atime rootpool/usr/ports/distfiles ; mount | grep distfiles
NAME                          PROPERTY  VALUE                         SOURCE
rootpool/usr/ports/distfiles  atime     on                            default
rootpool/usr/ports/distfiles on /usr/ports/distfiles (zfs, local)

Scot
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