UDEV issue.. USB triggers script but USB doesn't mount

Question

So I have the UDEV rule:

ACTION=="add", SUBSYSTEMS=="block", KERNEL=="sd[a-z]1", RUN+="/usr/local/bin/script.sh"

This is saved in /etc/udev/rules.d/10-usb.rules

I want it to trigger the script when any USB key is attached.

I am testing with 3 different USB sticks.

Without the UDEV rule in place (well a blank 10-usb.rules file), the USB auto mounts fine.

With the UDEV rule in place (I use udevadm control --reload then udevadm trigger at each change), the script triggers (in the script I have some files being copied first on the Pi, before over to the USB) but the USB doesn't mount properly, hence messing up the file transfer.

Looking with tail -f /var/log/messages I can see the USB being attached, but it stays greyed out in the top right corner of the Pi (eject devices).

Any ideas as to why the mounting issue comes into play when the UDEV rule is in place?

Answer 1

I suppose the USB automount on your system also happens via UDEV rules (typically /etc/udev/rules.d/80-udisks2.rules or a similar file in /usr/lib/udev/). Since your script relies on the drive already being mounted, you could try to make sure your rule executes after udisks. I would start with renaming your UDEV rule file to /etc/udev/rules.d/99-usb.rules and checking whether that helps.