Comment # 28 on bug 1080485 from Martin Wilck

(In reply to Neil Rickert from comment #27)
> I am now seeing these errors on every shutdown.  This is with a KVM virtual
> machine, where I previously never could produced the problem.  And I do have
> "plymouth.enable=0".

IIUC use see these messages for a while, then they stop and the reboot succeeds
(how long? how many messages)?

If actually some library from the root FS was used by some process running
outside of it, then the error should persist and the remove ioctl should
consistently fail, causing the shutdown process to time out.

> My personal opinion:  this is all a mistake.  The system should not try to
> disassemble device mapper setup.

I'm not sure where this happens. I guess it's the stop job of
"blk-availability.service". Could you try to mask that service and see if the
problem disappears?

Wrt this being a "mistake", the blkdeactivate script was introduced to LVM by
Red Hat in 2012. I didn't find an explicit rationale, but as they're unlikely
to have written that code without a purpose, I guess they were seeing data
corruption of some sort if it's not done.