Ubuntu snap cannot work on ZFS

[tomposmiko]

System information

Type	Version/Name
Distribution Name	Ubuntu Disco
Distribution Version	19.04
Linux Kernel	4.20.0-042000rc7-generic
Architecture	amd64
ZFS Version	0.8.0-rc3
SPL Version	0.8.0-rc3

Describe the problem you're observing

Snap cannot work at all if it's on ZFS:

$ vlc
cannot create user data directory: /tank/tompos/snap/vlc/770: Read-only file system

$ slack
cannot create user data directory: /tank/tompos/snap/slack/10: Permission denied

$ xonotic
cannot create user data directory: /tank/tompos/snap/xonotic/34: Read-only file system

$ lxc
cannot create user data directory: /tank/tompos/snap/lxd/9886: Read-only file system

Describe how to reproduce the problem

$ snap install

ps.: Thanks to the snap product devs for the naming.

[ghfields]

Check the zfs mailing list (Subject: ffmpeg on ZFS). Turned out ffmpeg snap app didn't work while apt version did. Seemed to be filesystem sandboxing imposed by snap.

http://list.zfsonlinux.org/pipermail/zfs-discuss/2018-December/033025.html