Evince won't work for users on ZFS file systems?
I have a couple of systems running Ubuntu Budgie 19.04. No complaints on Evince with the laptop which has ext4 file system for /home. My desktop has a pair of large drives set up with ZFS, user accounts are configured to use /bigdisks/home instead of /home, and I get this error when trying to start Evince. It's not a permissions problem, user owns the whole space, and it's not a read only file system.
"cannot create user data directory: /bigdisks/home/nealr/snap/evince/101: Read-only file system"
I checked /var/log/syslog and found this:
Jun 24 09:27:30 workstation plank.desktop[8038]: cannot create user data directory: /bigdisks/home/nealr/snap/evince/101: Read-only file system
And then I ran the app under strace and captured output.
https://gist.github.com/NetwarSystem/90239522ce412c7e59f59845f0e03945
Here are the attempts to access /home/.
newfstatat(AT_FDCWD, "/bigdisks/home/nealr/snap/evince/101", {st_mode=S_IFDIR|0755, st_size=2, ...}, 0) = 0
newfstatat(AT_FDCWD, "/bigdisks/home/nealr/snap/evince/common", {st_mode=S_IFDIR|0755, st_size=2, ...}, 0) = 0
readlinkat(AT_FDCWD, "/bigdisks/home/nealr/snap/evince/current", "101", 128) = 3
newfstatat(AT_FDCWD, "/bigdisks/home/nealr/.Xauthority", {st_mode=S_IFREG|0600, st_size=47, ...}, 0) = 0
openat(AT_FDCWD, "/bigdisks/home/nealr/.Xauthority", O_RDONLY|O_CLOEXEC) = 5
lstat("/bigdisks/home", {st_mode=S_IFDIR|0755, st_size=4, ...}) = 0
lstat("/bigdisks/home/nealr", {st_mode=S_IFDIR|0755, st_size=160, ...}) = 0
lstat("/bigdisks/home/nealr/.Xauthority", {st_mode=S_IFREG|0600, st_size=47, ...}) = 0
Spent some time wandering around, then noticed this - the /snap/ directory is owned by root and mounted RO.
mount | grep "evince"
/var/lib/snapd/snaps/evince_101.snap on /snap/evince/101 type squashfs (ro,nodev,relatime,x-gdu.hide)
nsfs on /run/snapd/ns/evince.mnt type nsfs (rw)
I only recently started using Budgie, this is first platform where I've used snap instead of apt for some packages.
Is this an Evince bug? Or clue deficit disorder for a user new to both snap and ZFS?