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like Gecko) Chrome/67.0.3396.99 Safari/537.36
Build Identifier: 

updating tumbleweed with zypper dup to TW 2018-06-26 results in systems which
successfully loads grub. However, starting the OS fails because it cannot find
root device. The path to the root device and root device name are correct,
however, the following error is displayed before the startup process tries to
access to the root device:

"device-mapper: table 254:0 multipath: error getting device"

Not sure why device mapper is involved to begin with as I don't use a device
mapper setup. 

Reproducible: Always

Steps to Reproduce:
1. zypper dup --no-allow-vendor-change
2. reboot
3. select the default kernel image
Actual Results:  
after selecting the new TW version, a short notice is displayed stating 
"device-mapper: table 254:0 multipath: error getting device" followed by an
animated boot screen. Hitting the ESC key displays: 
a start job is running for device ..... (with device id of the root device)

The start job never finishes. The system can be rebooted with Sys-Req S,U,B

Expected Results:  
Normal startup

The current system runs kernel 4.16.0-1-default, with the following disk
layout:

UUID=7f67d2ea-51cc-4e6c-9e82-2e17c47edc86  swap                     swap  
defaults                        0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /                        btrfs 
defaults                        0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /boot/grub2/i386-pc      btrfs 
subvol=@/boot/grub2/i386-pc     0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /boot/grub2/x86_64-efi   btrfs 
subvol=@/boot/grub2/x86_64-efi  0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /opt                     btrfs 
subvol=@/opt                    0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /srv                     btrfs 
subvol=@/srv                    0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /tmp                     btrfs 
subvol=@/tmp                    0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /usr/local               btrfs 
subvol=@/usr/local              0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/cache               btrfs 
subvol=@/var/cache              0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/crash               btrfs 
subvol=@/var/crash              0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/lib/libvirt/images  btrfs 
subvol=@/var/lib/libvirt/images  0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/lib/machines        btrfs 
subvol=@/var/lib/machines       0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/lib/mailman         btrfs 
subvol=@/var/lib/mailman        0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/lib/mariadb         btrfs 
subvol=@/var/lib/mariadb        0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/lib/mysql           btrfs 
subvol=@/var/lib/mysql          0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/lib/named           btrfs 
subvol=@/var/lib/named          0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/lib/pgsql           btrfs 
subvol=@/var/lib/pgsql          0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/log                 btrfs 
subvol=@/var/log                0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/opt                 btrfs 
subvol=@/var/opt                0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/spool               btrfs 
subvol=@/var/spool              0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /var/tmp                 btrfs 
subvol=@/var/tmp                0  0
UUID=d5d82692-28ad-43d3-860c-22b4991a15cc  /.snapshots              btrfs 
subvol=@/.snapshots             0  0
UUID=CE1E-17A4                             /boot/efi                vfat  
umask=0002,utf8=true            0  0
UUID=4e9fb774-a924-4399-9539-43c17563a138  /home                    btrfs 
defaults                        0  0