canmount property switches to noauto in user's home dataset

[Andreas Hasenack]

I can't be 100% sure about this, but I think anytime I have zsys installed and reboot, my user's dataset has its canmount property set to noauto.

That property is set to off in the parent dataset USERDATA:
$ zfs get canmount,mounted,mountpoint rpool/USERDATA
NAME PROPERTY VALUE SOURCE
rpool/USERDATA canmount off local
rpool/USERDATA mounted no -
rpool/USERDATA mountpoint / local

In mine, it's on:
$ zfs get canmount,mounted,mountpoint rpool/USERDATA/andreas_xk451a
NAME PROPERTY VALUE SOURCE
rpool/USERDATA/andreas_xk451a canmount on local
rpool/USERDATA/andreas_xk451a mounted yes -
rpool/USERDATA/andreas_xk451a mountpoint /home/andreas local

I then install zsys 0.2.2:
Get:1 http://br.archive.ubuntu.com/ubuntu eoan/universe amd64 zsys amd64 0.2.2 [1.303 kB]

And reboot.

When I login again, my home is gone, because the andreas_xk451a dataset is not mounted. Running zfs get again confirms that the canmount property changed back to noauto.

NAME PROPERTY VALUE SOURCE
rpool/USERDATA/andreas_xk451a canmount noauto local
rpool/USERDATA/andreas_xk451a mounted no -
rpool/USERDATA/andreas_xk451a mountpoint /home/andreas local

NAME PROPERTY VALUE SOURCE
rpool/USERDATA canmount off local
rpool/USERDATA mounted no -
rpool/USERDATA mountpoint / local

Since "noauto" isn't even the parent's setting, and the SOURCE of the property is marked as "local", something is doing it on purpose. My guess it's zsys, because after I remove it, this behavior stops.

[Didier Roche-Tolomelli (didrocks)]

I think the issue is that you installed before the final release, as the properties were renamed from `org.zsys` to `com.ubuntu.zsys` for property. As zsys isn't seeded by default, we were told to not migrate the handful of users having installed a pre-released.

Can you confirm that canmount is then correctly set to "on", once you rename the user's property?

[Didier Roche-Tolomelli (didrocks)]

(settings as incomplete until you confirm this is the issue)

[Andreas Hasenack (ahasenack)]

Correct, with the new property, it works correctly.

There is no way to get rid of the org.zsys one though, is there? Apparently there is no way to remove a user property in zfs.

[satmandu (satadru-umich)]

You can remove that property thus:

sudo zfs inherit org.zsys:bootfs-datasets rpool/USERDATA/<username>_<local_user_string>

[Brian Elliott Finley (finley)]

I am having the same issue with canmount=on switching to canmount=noauto on a
user's dataset, and I'm using the final release of 19.10, so perhaps this will
help.

Version Details:
------------------------------------------------------------------------
v-eight# cat /etc/issue.net
Ubuntu 19.10

v-eight# dpkg -l zfs\* zsys | grep ^ii
ii zfs-auto-snapshot 1.2.4-2 all ZFS automatic snapshot service
ii zfs-initramfs 0.8.1-1ubuntu14.2 amd64 OpenZFS root filesystem capabilities for Linux - initramfs
ii zfs-zed 0.8.1-1ubuntu14.2 amd64 OpenZFS Event Daemon
ii zfsutils-linux 0.8.1-1ubuntu14.2 amd64 command-line tools to manage OpenZFS filesystems
ii zsys 0.2.2+19.04 amd64 ZFS SYStem integration

Here's how it all went down:
-------------------------------------
I did a full disk ZFS install, then I installed zsys.

I wanted an encrypted home dir, so I created a new dataset
(rpool/USERDATA/bfinley-encrypted) and copied all of my data into it.

    As a side note, I configured boot time decryption as per option 3 in
    chungy's HOWTO (https://github.com/chungy/zfs-boottime-encryption). This
    is working great and keys are successfully loaded at boot time. Also, a
    second encrypted non-homedir dataset I created at the same time is
    successfully mounted automatically
    (rpool/ROOT/ubuntu_rkiozo/var/lib/mlocate), and retains it's 'canmount=on'
    setting.

I then changed the mountpoint for the system created homedir dataset from
'/home/bfinley' to 'none'.

And changed the mountpoint for the new homedir dataset from
'/home/bfinley-encrypted' to '/home/bfinley' and set it to 'canmount=on'.

After rebooting, the mlocate dataset mounted automatically, but the homedir
dataset did not. 'zfs get keystatus rpool/USERDATA/bfinley' showed
'available', but 'canmount' had been changed to 'noauto'.

At this point, I could 'zfs set canmount=on rpool/USERDATA/bfinley' and do a
'zfs mount -a', and it would mount.

But again, after reboot, 'canmount=on' was changed to 'canmount=noauto'.

So, I looked for other differences in the settings between the system created
homedir and new new one. The system created homedir has these additional
settings:

    com.ubuntu.zsys:bootfs-datasets rpool/ROOT/ubuntu_rkiozo
    org.zsys:bootfs-datasets rpool/ROOT/ubuntu_rkiozo
    com.ubuntu.zsys:last-used 1577134248

Based on that discovery, I added the first to settings to my new dataset
(omitting the third, as I expected it would be added automatically via zsys) and rebooted.

    zfs set com.ubuntu.zsys:bootfs-datasets=rpool/ROOT/ubuntu_rkiozo rpool/USERDATA/bfinley
    zfs set org.zsys:bootfs-datasets=rpool/ROOT/ubuntu_rkiozo rpool/USERDATA/bfinley

After reboot, my new encrypted homedir was mounted automatically!

    As a side note, I took a look and 'com.ubuntu.zsys:last-used' was indeed
    automatically set with a timestamp.

SOLUTION and Conclusions
------------------------------------------------------------------------
1) I now have a solution to the problem at hand, and hopefully others do too.
   The solution summary for me was to set 'com.ubuntu.zsys:...