ZFS Dataset is Busy Solutionzfs ubuntu
Solution on Ubuntu:
Using the following command and find with process is holding the dataset.
grep zroot/2013-10-15T065955229209 /proc/*/mounts
note: replace zroot/2013-10-15T065955229209 as your mount point.
Then find the process name and stop or restart the service. For me, it was systemd-timesyncd and I restarted it.
$ ps -p 11438 PID TTY TIME CMD 11438 ? 00:00:00 systemd-timesyn $ ps -ef |grep 11438 systemd+ 11438 1 0 09:11 ? 00:00:00 /lib/systemd/systemd-timesyncd $ sudo systemctl restart systemd-timesyncd