Ubuntu – Udevadm settle not working

18.04encryptionlvmmount

I just upgraded to 18.04 on my NAS. I have a script that prompts my user for a luks password and then mounts the drive after it's decrypted. This used to work:

cryptsetup luksOpen /dev/md0 md0_crypt
udevadm settle --exit-if-exists=/dev/mapper/files--vg-main
mount /dev/mapper/files--vg-main /main

However after updating to 18.04 this stopped working and I get: mount: /main: special device /dev/mapper/files--vg-main does not exist.

I have not found a solution just googling. My LUKS container is my pv. I have it in a Vol group called files-vg. I then have one logical volume with a path /dev/files-vg/main. Hence why I'm looking for /dev/mapper/files–vg-main

Edit: To clarify, the udevadm settle line does not wait long enough for the LV to become available so the mount fails. I can manually call mount and it will work afterward.

Best Answer

Here's an ugly workaround that I don't have a LUKS container to test on:

udevadm info /dev/mapper/files--vg-main

Where /dev/mapper/files--vg-main is the device you are checking for. if [ $? -eq 0 ] then the command was successful meaning the device exists and you can mount it.

else you'd have to loop and check again.

As a side note you can find some useful udev debugging ideas on this page.

Script to mount drive - `mount-menu.sh`

The mount-menu.sh script allows you to select unmounted drives/partitions for mounting. To call the script use: sudo mount-menu.sh. This screen appears tailored to your unique machine environment:

Use arrow keys to select the partition and press Enter

The menu clears and leaves this information in your terminal:

=====================================================================
Mount Device:  /dev/nvme0n1p10
Mount Name:    /mnt/mount-menu.FPRAW
File System:   ext4
ID:            Ubuntu
RELEASE:       18.04
CODENAME:      bionic
DESCRIPTION:   Ubuntu 18.04.1 LTS
 Size  Used Avail Use%
  27G  7.9G   18G  32%

Now you can use: cd /mnt/mount-menu.FPRAW to access your external drive's partition.

Then you can use cd home/YOUR_NAME being mindful not to put a / in front of home. Should you use cd /home it would take you to your boot drive and out of the external drive.

`mount-menu.sh` script contents

To create the script open the terminal and type:

sudo -H gedit /usr/local/bin/mount-menu.sh

Then copy the code below and paste it into gedit. Save the file and exit gedit.

Now mark the file as executable using:

sudo chmod a+x /usr/local/bin/mount-menu.sh

Here's the script to copy:

#!/bin/bash

# NAME: mount-menu.sh
# PATH: /usr/local/bin
# DESC: Select unmounted partition for mounting
# DATE: May 9, 2018. Modified May 11, 2018.

# $TERM variable may be missing when called via desktop shortcut
CurrentTERM=$(env | grep TERM)
if [[ $CurrentTERM == "" ]] ; then
    notify-send --urgency=critical \ 
                "$0 cannot be run from GUI without TERM environment variable."
    exit 1
fi

# Must run as root
if [[ $(id -u) -ne 0 ]] ; then echo "Usage: sudo $0" ; exit 1 ; fi

#
# Create unqique temporary file names
#

tmpMenu=$(mktemp /tmp/mount-menu.XXXXX)     # Menu list
tmpInfo=$(mktemp /tmp/mount-menu.XXXXX)     # Mount Parition Info
tmpWork=$(mktemp /tmp/mount-menu.XXXXX)     # Work file
MountName=$(mktemp -d /mnt/mount-menu.XXXXX)  # Mount directory name

#
# Function Cleanup () Removes temporary files
#

CleanUp () {
    [[ -f $tmpMenu ]] && rm -f $tmpMenu     # If temporary files created
    [[ -f $tmpInfo ]] && rm -f $tmpInfo     #  at various program stages
    [[ -f $tmpWork ]] && rm -f $tmpWork     #  remove them before exiting.
}


#
# Mainline
#

lsblk -o NAME,FSTYPE,LABEL,SIZE,MOUNTPOINT > $tmpMenu

i=0
SPACES='                                                                     '
DoHeading=true
AllPartsArr=()      # All partitions.

# Build whiptail menu tags ($i) and text ($Line) into array

while read -r Line; do
    if [[ $DoHeading == true ]] ; then
        DoHeading=false                     # First line is the heading.
        MenuText="$Line"                    # Heading for whiptail.
        FSTYPE_col="${Line%%FSTYPE*}"           
        FSTYPE_col="${#FSTYPE_col}"         # FS Type, ie `ext4`, `ntfs`, etc.
        MOUNTPOINT_col="${Line%%MOUNTPOINT*}"
        MOUNTPOINT_col="${#MOUNTPOINT_col}" # Required to ensure not mounted.
        continue
    fi

    Line="$Line$SPACES"                     # Pad extra white space.
    Line=${Line:0:74}                       # Truncate to 74 chars for menu.

    AllPartsArr+=($i "$Line")               # Menu array entry = Tag# + Text.
    (( i++ ))

done < $tmpMenu                             # Read next "lsblk" line.

#
# Display whiptail menu in while loop until no errors, or escape,
# or valid partion selection .
#

DefaultItem=0

while true ; do

    # Call whiptail in loop to paint menu and get user selection
    Choice=$(whiptail \
        --title "Use arrow, page, home & end keys. Tab toggle option" \
        --backtitle "Mount Partition" \
        --ok-button "Select unmounted partition" \
        --cancel-button "Exit" \
        --notags \
        --default-item "$DefaultItem" \
        --menu "$MenuText" 24 80 16 \
        "${AllPartsArr[@]}" \
        2>&1 >/dev/tty)

    clear                                   # Clear screen.
    if [[ $Choice == "" ]]; then            # Escape or dialog "Exit".
        CleanUp
        exit 1;
     fi

    DefaultItem=$Choice                     # whiptail start option.
    ArrNdx=$(( $Choice * 2 + 1))            # Calculate array offset.
    Line="${AllPartsArr[$ArrNdx]}"          # Array entry into $Line.

    # Validation - Don't wipe out Windows or Ubuntu 16.04:
    # - Partition must be ext4 and cannot be mounted.

    if [[ "${Line:MOUNTPOINT_col:4}" != "    " ]] ; then
        echo "Partition is already mounted."
        read -p "Press <Enter> to continue"
        continue
    fi

    # Build "/dev/Xxxxx" FS name from "├─Xxxxx" menu line
    MountDev="${Line%% *}"
    MountDev=/dev/"${MountDev:2:999}"

    # Build File System Type
    MountType="${Line:FSTYPE_col:999}"
    MountType="${MountType%% *}"

    break                                   # Validated: Break menu loop.

done                                        # Loop while errors.

#
# Mount partition
#

echo ""
echo "====================================================================="
mount -t auto $MountDev $MountName


# Display partition information.
echo "Mount Device=$MountDev" > $tmpInfo
echo "Mount Name=$MountName" >> $tmpInfo
echo "File System=$MountType" >> $tmpInfo

# Build Mount information (the partition selected for cloning to)
LineCnt=$(ls $MountName | wc -l)
if (( LineCnt > 2 )) ; then 
    # More than /Lost+Found exist so it's not an empty partition.
    if [[ -f $MountName/etc/lsb-release ]] ; then
        cat $MountName/etc/lsb-release >> $tmpInfo
    else
        echo "No LSB-Release file on Partition." >> $tmpInfo
    fi
else
    echo "Partition appears empty" >> $tmpInfo
    echo "/Lost+Found normal in empty partition" >> $tmpInfo
    echo "First two files/directories below:" >> $tmpInfo
    ls $MountName | head -n2 >> $tmpInfo
fi

sed -i 's/DISTRIB_//g' $tmpInfo      # Remove DISTRIB_ prefix.
sed -i 's/=/:=/g' $tmpInfo           # Change "=" to ":="
sed -i 's/"//g' $tmpInfo             # Remove " around "Ubuntu 16.04...".

# Align columns from "Xxxx:=Yyyy" to "Xxxx:      Yyyy"
cat $tmpInfo | column -t -s '=' > $tmpWork
cat $tmpWork > $tmpInfo

# Mount device free bytes
df -h --output=size,used,avail,pcent "$MountDev" >> $tmpInfo

# Display partition information.
cat $tmpInfo

CleanUp                             # Remove temporary files

exit 0

`umount-menu.sh` to Unmount Drives/Partitions

Repeat the file creation / execute bit marking process for the script umount-menu.sh. This script only unmounts drives / partitions that were mounted by mount-menu.sh. It has the same selection menu and completes with the message:

=====================================================================

/dev/nvme0n1p10 mounted on /mnt/mount-menu.FPRAW unmounted.

To call the script use: sudo umount-menu.sh

`umount-menu.sh` bash script:

!/bin/bash

# NAME: umount-menu.sh
# PATH: /usr/local/bin
# DESC: Select mounted partition for unmounting
# DATE: May 10, 2018. Modified May 11, 2018.

# $TERM variable may be missing when called via desktop shortcut
CurrentTERM=$(env | grep TERM)
if [[ $CurrentTERM == "" ]] ; then
    notify-send --urgency=critical \ 
                "$0 cannot be run from GUI without TERM environment variable."
    exit 1
fi

# Must run as root
if [[ $(id -u) -ne 0 ]] ; then echo "Usage: sudo $0" ; exit 1 ; fi

#
# Create unqique temporary file names
#

tmpMenu=$(mktemp /mnt/mount-menu.XXXXX)   # Menu list

#
# Function Cleanup () Removes temporary files
#

CleanUp () {
    [[ -f "$tmpMenu" ]] && rm -f "$tmpMenu" #  at various program stages
}


#
# Mainline
#

lsblk -o NAME,FSTYPE,LABEL,SIZE,MOUNTPOINT > "$tmpMenu"

i=0
SPACES='                                                                     '
DoHeading=true
AllPartsArr=()      # All partitions.

# Build whiptail menu tags ($i) and text ($Line) into array

while read -r Line; do
    if [[ $DoHeading == true ]] ; then
        DoHeading=false                     # First line is the heading.
        MenuText="$Line"                    # Heading for whiptail.
        MOUNTPOINT_col="${Line%%MOUNTPOINT*}"
        MOUNTPOINT_col="${#MOUNTPOINT_col}" # Required to ensure mounted.
        continue
    fi

    Line="$Line$SPACES"                     # Pad extra white space.
    Line=${Line:0:74}                       # Truncate to 74 chars for menu.

    AllPartsArr+=($i "$Line")               # Menu array entry = Tag# + Text.
    (( i++ ))

done < "$tmpMenu"                           # Read next "lsblk" line.

#
# Display whiptail menu in while loop until no errors, or escape,
# or valid partion selection .
#

DefaultItem=0

while true ; do

    # Call whiptail in loop to paint menu and get user selection
    Choice=$(whiptail \
        --title "Use arrow, page, home & end keys. Tab toggle option" \
        --backtitle "Mount Partition" \
        --ok-button "Select unmounted partition" \
        --cancel-button "Exit" \
        --notags \
        --default-item "$DefaultItem" \
        --menu "$MenuText" 24 80 16 \
        "${AllPartsArr[@]}" \
        2>&1 >/dev/tty)

    clear                                   # Clear screen.

    if [[ $Choice == "" ]]; then            # Escape or dialog "Exit".
        CleanUp
        exit 1;
     fi

    DefaultItem=$Choice                     # whiptail start option.
    ArrNdx=$(( $Choice * 2 + 1))            # Calculate array offset.
    Line="${AllPartsArr[$ArrNdx]}"          # Array entry into $Line.

    if [[ "${Line:MOUNTPOINT_col:15}" != "/mnt/mount-menu" ]] ; then
        echo "Only Partitions mounted by mount-menu.sh can be unounted."
        read -p "Press <Enter> to continue"
        continue
    fi

    # Build "/dev/Xxxxx" FS name from "├─Xxxxx" menu line
    MountDev="${Line%% *}"
    MountDev=/dev/"${MountDev:2:999}"

    # Build Mount Name
    MountName="${Line:MOUNTPOINT_col:999}"
    MountName="${MountName%% *}"

    break                                   # Validated: Break menu loop.

done                                        # Loop while errors.

#
# Unmount partition
#

echo ""
echo "====================================================================="
umount "$MountName" -l                      # Unmount the clone
rm  -d "$MountName"                         # Remove clone directory

echo $(tput bold)                           # Set to bold text
echo $MountDev mounted on $MountName unmounted.
echo $(tput sgr0)                           # Reset to normal text

CleanUp                                     # Remove temporary files

exit 0

Best Answer

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