Comment 2 for bug 1780196

I found the commit where introduced this blkdeactivate: https://sourceware.org/git/?p=lvm2.git;a=commit;h=c698ee14bbb1310cf2383c8977d14a8e29139f8c

> Traverses the tree of block devices and tries to deactivate them.
> Currently, it supports device-mapper-based devices together with LVM.
> See man/blkdeactivate.8 for more info.
>
> It is targeted for use during shutdown to properly deactivate the
> whole block device stack - systemd and init scripts are provided as
> well. However, it might be used directly on command line too.

In this case, this stuff runs too early, as I think.