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A.B.
Asked: 2015-09-07 08:24:53 +0800 CST

Ignore one partition of two of an USB stick via udev

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I have a USB stick with two partitions. After plugging the stick I use the following command to find the device.

dmesg

Example output

[11195.236020] usb 2-2: new high-speed USB device number 9 using ehci-pci
[11195.375432] usb 2-2: New USB device found, idVendor=058f, idProduct=6387
[11195.375436] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[11195.375439] usb 2-2: Product: Mass Storage
[11195.375441] usb 2-2: Manufacturer: Generic
[11195.375444] usb 2-2: SerialNumber: 605DD851
[11195.375968] usb-storage 2-2:1.0: USB Mass Storage device detected
[11195.376732] scsi host10: usb-storage 2-2:1.0
[11196.377830] scsi 10:0:0:0: Direct-Access     Generic  Flash Disk       8.07 PQ: 0 ANSI: 4
[11196.378159] sd 10:0:0:0: Attached scsi generic sg3 type 0
[11196.379647] sd 10:0:0:0: [sdc] 15769600 512-byte logical blocks: (8.07 GB/7.51 GiB)
[11196.381548] sd 10:0:0:0: [sdc] Write Protect is off
[11196.381552] sd 10:0:0:0: [sdc] Mode Sense: 23 00 00 00
[11196.383579] sd 10:0:0:0: [sdc] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[11196.390454]  sdc: sdc1 sdc2
[11196.394696] sd 10:0:0:0: [sdc] Attached SCSI removable disk

Therefore, my device is /sdc and my partitions /dev/sdc1 and /dev/sdc2

I used the both commands to get their UUIDs

udevadm info /dev/sdc1 | grep ID_FS_UUID=

Example output

E: ID_FS_UUID=dbf323e9-8d63-444c-9c11-76b9b9a0fed4

and

udevadm info /dev/sdc2 | grep ID_FS_UUID=

Example output

E: ID_FS_UUID=0eeb7004-8955-4358-a205-07d7376adb8c

Therefore my UUIDs are dbf323e9-8d63-444c-9c11-76b9b9a0fed4 and 0eeb7004-8955-4358-a205-07d7376adb8c

or per partition

/dev/sdc1 >> dbf323e9-8d63-444c-9c11-76b9b9a0fed4
/dev/sdc2 >> 0eeb7004-8955-4358-a205-07d7376adb8c

Now I created a file /etc/udev/rules.d/100-myusb.rules

sudo nano /etc/udev/rules.d/100-myusb.rules

and added the rule below

KERNEL=="sd??", ENV{ID_FS_UUID}=="0eeb7004-8955-4358-a205-07d7376adb8c", ENV{UDISKS_IGNORE}="1"

and restarted udev

sudo service udev restart

But after plugging the stick again, both partitions are shown in Files aka Nautilus

What I'm doing wrong?

Edit So 6. Sep 21:07:50 CEST 2015

The rule

KERNEL=="sd??", ENV{ID_FS_UUID}=="0eeb7004-8955-4358-a205-07d7376adb8c", RUN+="/bin/mkdir /tmp/folder1"

creates the folder /tmp/folder1

And for @Sneetsher

KERNEL=="sd??", ENV{ID_FS_UUID}=="0eeb7004-8955-4358-a205-07d7376adb8c", RUN+="/usr/bin/env > /tmp/udev-partition-env.log"

works, but the output file is env_root.output? o_O

Edit Mo 7. Sep 20:31:06 CEST 2015

Tested and doesn't works

KERNEL=="sd??", ENV{ID_FS_UUID}=="0eeb7004-8955-4358-a205-07d7376adb8c", ENV{UDISKS_AUTO}="0", ENV{UDISKS_SYSTEM}="0"

and

KERNEL=="sd??", ENV{ID_FS_UUID}=="0eeb7004-8955-4358-a205-07d7376adb8c", ENV{UDISKS_AUTO}="0"
15.04

1 Answers

  1. Best Answer

    • Finally, I setup same environment Ubuntu 15.04 in a VirtualBox machine.

      ACTION=="add", ENV{ID_FS_UUID}=="bf50cb5d-60bf-44de-9a8f-1bf74850a5a1", ENV{UDISKS_IGNORE}="1"

      It works as perfectly as expected.

    • :D I hate 3 digits prefix 100- (common/standard is 2), So I'm using 99-'s most the time. I never tried it before, renaming it to be similar to yours:

      # mv /etc/udev/rules.d/99-sneetsher-tests.rules /etc/udev/rules.d/100-myusb-sneetsher-tests.rules

      Voila! Now It does not work.

      The rule is overridden by other rules, pretty sure the system ones from /lib/udev/rules.d/

      You may try listing all rules files, to check:

      find /etc/udev/rules.d/ /lib/udev/rules.d/ -iname "*.rules" -printf "%f\n" | sort

      RULES FILES

      The udev rules are read from the files located in the system rules directory /lib/udev/rules.d, the volatile runtime directory /run/udev/rules.d and the local administration directory /etc/udev/rules.d. All rules files are collectively sorted and processed in lexical order, regardless of the directories in which they live. However, files with identical filenames replace each other. Files in /etc have the highest priority, files in /run take precedence over files with the same name in /lib. This can be used to override a system-supplied rules file with a local file if needed; a symlink in /etc with the same name as a rules file in /lib, pointing to /dev/null, disables the rules file entirely. Rule files must have the extension .rules; other extensions are ignored.

      Source: man udev

    • May be this is the best way to check using udevadm test <path>, example:

      udevadm test /sys/devices/pci0000:00/0000:00:06.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0/block/sdb/sdb2

      Test it for both names 100-myusb.rules & 99-myusb.rules, you will see which order the rules files read and which rules triggered.

      Reference: Which udev rule triggered?

    • 2