[systemd-devel] Systemd loads units before btrfs subvolumes are mounted

[Chris Murphy]

On Wed, May 25, 2016 at 9:21 AM, Lennart Poettering
<lennart at poettering.net> wrote:

> What I don't understand in your case though is why you use an explicit
> mount for /opt anyway... The nice thing about btrfs is that subvolumes
> behave pretty much like normal directories that just have a bit more
> features. And because of that there's no need to mount them
> explicitly. Just create a subvolume normally and everything should be
> good, it will then be available at the right place the instant the
> parent subvolume is mounted too.

Not on Fedora. The Anaconda installer creates a subvolume out of every
user defined mountpoint. The subvolumes are created at the top level
of the btrfs volume, and then fstab is populated with each of those
subvolumes and their mountpoints. So the subvolumes do not appear in a
normal FHS layout, they only end up in the FHS layout as a result of
fstab being acted upon.

And also not on openSUSE which uses subvolumes to inhibit snapshot
creation of the top level, and this includes /opt and many other
things. The fstab there looks like this:

https://da.gd/goBp

And btrfs sub list /

https://da.gd/Qjbtf



-- 
Chris Murphy