Not sure if this is a bug, but I can't find any documentation at http://clamfs.sourceforge.net/
Having read
https://wiki.archlinux.org/index.php/Systemd#Writing_unit_files
I have configured a root of "/home" at "/mnt/home" and set up /etc/systemd/system/multi-user.target.wants/clamfs.service
ClamFS starts on startup, but attempts to access files from /mnt/home fail, apparently for lack of read access.
syslog shows:
Jun 25 11:00:47 tommy clamd[1098]: WARNING: lstat() failed on: /home/user/.xsession-errors
Jun 25 11:00:47 tommy clamfs: (caja:3678) (user:1000) /home/user/.xsession-errors: lstat() failed: Permission denied. ERROR
Jun 25 11:00:49 tommy clamd[1098]: WARNING: lstat() failed on: /home/user/PDF/catalogue_template4.pdf
Jun 25 11:00:49 tommy clamfs: (evince-thumbnailer:3686) (user:1000) /home/user/PDF/catalogue_template4.pdf: lstat() failed: Permission denied. ERROR
Jun 25 11:00:49 tommy org.mate.atril.Daemon[2094]: RegisterDocument registered owner ':1.74' for URI 'file:///mnt/home/user/PDF/catalogue_template4.pdf'
Jun 25 11:00:49 tommy org.mate.atril.Daemon[2094]: Watch name':1.74' appeared with owner ':1.74'
Jun 25 11:00:51 tommy org.mate.atril.Daemon[2094]: UnregisterDocument URI 'file:///mnt/home/user/PDF/catalogue_template4.pdf'
Jun 25 11:01:21 tommy org.mate.atril.Daemon[2094]: Timeout; exiting daemon.
Jun 25 11:01:42 tommy clamd[1098]: WARNING: lstat() failed on: /home/user/z.txt
Jun 25 11:01:42 tommy clamfs: (kate:12445) (user:1000) /home/user/z.txt: lstat() failed: Permission denied. ERROR
With thanks