I created an udev rule that launches a shell script that creates a directory /media/my-disk when some specific USB HD is connected. It has been working many months, but after a reboot (probably some packages were updated) it shows the following message (in syslog) everytime I plug the drive in:
mkdir: cannot create directory '/media/my-disk': Read-only file system
I have added the following lines to the script:
And the result is:
root usb-mount.sh: /dev/mapper/sda3_crypt on / type btrfs (ro,relatime,ssd,space_cache,subvolid=257,subvol=/@)
So it seems udev is seeing the root filesystem as readonly, but if I execute
sudo mount manually it shows it mounted as read/write:
/dev/mapper/sda3_crypt on / type btrfs (rw,relatime,ssd,space_cache,subvolid=257,subvol=/@)
I've searched on the Internet and I've found the same exact problem but without a solution: https://www.raspberrypi.org/forums/viewtopic.php?t=210243
Restarting the udev service solves the problem until the next reboot.
What can I check solve it permanently?
NOTE: I am running Ubuntu 18.04.1 LTS