Comment 11 for bug 1858802

Test :: bionic

$ lsb_release -cs
bionic

$ uname -rv
4.15.0-72-generic #81-Ubuntu SMP Tue Nov 26 12:20:02 UTC 2019

$ dpkg -s bcache-tools xfsprogs | grep -i version
Version: 1.0.8-2build1
Version: 4.9.0+nmu1ubuntu2

$ sudo hexdump -C $BACKING_DEV | grep -m2 -e XFSB -e 'fe ed ba be'
00002000 58 46 53 42 00 00 10 00 00 00 00 00 00 03 f0 00 |XFSB............|
00007000 fe ed ba be 00 00 00 01 00 00 00 02 00 00 02 00 |................|

Before:

$ dpkg -s libblkid1 | grep -i version
Version: 2.31.1-0.4ubuntu3.4

$ sudo blkid -o udev -p $BACKING_DEV
ID_FS_AMBIVALENT=other:bcache other:xfs_external_log

After:

$ dpkg -s libblkid1 | grep -i version
Version: 2.31.1-0.4ubuntu3.5

$ sudo blkid -o udev -p $BACKING_DEV
ID_FS_UUID=46a3afa8-2c87-41b0-9c35-b766e0dddd6c
ID_FS_UUID_ENC=46a3afa8-2c87-41b0-9c35-b766e0dddd6c
ID_FS_TYPE=bcache
ID_FS_USAGE=other