Users repeatedly complain about lost data on USB thumb drives after they unplugged them without unmounting. We run Ubuntu 14.04 LTS on our machines. Auto-mounting is enabled.
As I am tired of remembering them to do a safe removal before unplugging, I want to make Ubuntu display an alert whenever a mounted USB drive is unplugged.
I thought of adding an udev rule that runs notify-send on removal in case the drive is still mounted. How can I determine if the USB drive was mounted upon removal?
Unfortunately, that's a thing Micro$oft actually got quite right: USB removal... And you'll keep on having this problem until you:
Disable auto-mounting
If users have to mount manually, it'll be easier to train them to dismount as well.
Create a udev rule that turns off all caching on USB disks...
I like Fabby's approach, but it is good to teach people about this bad habit (They are not working all the time on controlled machines). This is similar to an OSX feature, as described here.
There is a small difference that you may use it to know if it was a safe remove:
udev variable ID_PART_TABLE_TYPE=dos is set for sdx disk node (NOT partition node sdxY) in unsafe remove.
Where it is not set in safe remove
Noticed by monitoring udev events:
udevadm monitor -u --environment
Safe remove
UDEV [8292.380554] change /devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2:1.0/host16/target16:0:0/16:0:0:0/block/sdb (block)
ACTION=change
DEVLINKS=/dev/disk/by-id/usb-ADATA_USB_Flash_Drive_8d90ec535e6663-0:0 /dev/disk/by-path/pci-0000:00:14.0-usb-0:2:1.0-scsi-0:0:0:0
DEVNAME=/dev/sdb
DEVPATH=/devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2:1.0/host16/target16:0:0/16:0:0:0/block/sdb
DEVTYPE=disk
DISK_MEDIA_CHANGE=1
ID_BUS=usb
ID_INSTANCE=0:0
ID_MODEL=USB_Flash_Drive
ID_MODEL_ENC=USB\x20Flash\x20Drive\x20
ID_MODEL_ID=c96a
ID_PATH=pci-0000:00:14.0-usb-0:2:1.0-scsi-0:0:0:0
ID_PATH_TAG=pci-0000_00_14_0-usb-0_2_1_0-scsi-0_0_0_0
ID_REVISION=0.00
ID_SERIAL=ADATA_USB_Flash_Drive_8d90ec535e6663-0:0
ID_SERIAL_SHORT=8d90ec535e6663
ID_TYPE=disk
ID_USB_DRIVER=usb-storage
ID_USB_INTERFACES=:080650:
ID_USB_INTERFACE_NUM=00
ID_VENDOR=ADATA
ID_VENDOR_ENC=ADATA\x20\x20\x20
ID_VENDOR_ID=125f
MAJOR=8
MINOR=16
SEQNUM=2989
SUBSYSTEM=block
TAGS=:systemd:
USEC_INITIALIZED=554873
Unsafe remove
UDEV [8391.320280] remove /devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/host17/target17:0:0/17:0:0:0/block/sdb (block)
ACTION=remove
DEVLINKS=/dev/disk/by-id/usb-ADATA_USB_Flash_Drive_8d90ec535e6663-0:0 /dev/disk/by-path/pci-0000:00:14.0-usb-0:3:1.0-scsi-0:0:0:0
DEVNAME=/dev/sdb
DEVPATH=/devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/host17/target17:0:0/17:0:0:0/block/sdb
DEVTYPE=disk
ID_BUS=usb
ID_INSTANCE=0:0
ID_MODEL=USB_Flash_Drive
ID_MODEL_ENC=USB\x20Flash\x20Drive\x20
ID_MODEL_ID=c96a
ID_PART_TABLE_TYPE=dos
ID_PATH=pci-0000:00:14.0-usb-0:3:1.0-scsi-0:0:0:0
ID_PATH_TAG=pci-0000_00_14_0-usb-0_3_1_0-scsi-0_0_0_0
ID_REVISION=0.00
ID_SERIAL=ADATA_USB_Flash_Drive_8d90ec535e6663-0:0
ID_SERIAL_SHORT=8d90ec535e6663
ID_TYPE=disk
ID_USB_DRIVER=usb-storage
ID_USB_INTERFACES=:080650:
ID_USB_INTERFACE_NUM=00
ID_VENDOR=ADATA
ID_VENDOR_ENC=ADATA\x20\x20\x20
ID_VENDOR_ID=125f
MAJOR=8
MINOR=16
SEQNUM=3022
SUBSYSTEM=block
TAGS=:systemd:
USEC_INITIALIZED=436355
Create a udev rule (change useranme)
$ sudo nano /etc/udev/rules.d/90-unsafe-remove-notify.rules
ACTION=="remove", KERNEL=="sd?", ENV{ID_PART_TABLE_TYPE}!="", RUN+="/usr/bin/sudo -u username DISPLAY=:0 notify-send 'Unsafe Remove' '<b><i>Your long message</b></i>' -i /usr/share/icons/gnome/48x48/emotes/face-worried.png -t 10000"
Reload rules
sudo udevadm control --reload-rules
Another way, you may use a script (python) that connect to udisks DBUS. It has all needed info you need about partition mount/unmount, disks plug/unplug...
Reference/Source: Gentoo Wiki: Udisks - USB_Thumb_Drive_Example
