This is again caused by /etc/init.d/network bringing network interfaces down before we can cleanly unmount /usr in shutdown initrd.

We already have following code in network script that is supposed to solve the same issue for rootfs,

rootfs=$(awk '{ if ($1 !~ /^[ \t]*#/ && $2 == "/" && $3 != "rootfs") { print $3; }}' /proc/mounts)
rootopts=$(awk '{ if ($1 !~ /^[ \t]*#/ && $2 == "/") { print $4; }}' /etc/mtab)
	
if [[ "$rootfs" == nfs* || "$rootopts" =~ _r?netdev ]] ; then
	exit 1
fi

systemctl show --property=RequiredBy -- -.mount | grep -q 'remote-fs.target' && exit 1

When I added following to network script I was able to cleanly reboot the machine.

usrfs=$(awk '{ if ($1 !~ /^[ \t]*#/ && $2 == "/usr") { print $3; }}' /proc/mounts)
usropts=$(awk '{ if ($1 !~ /^[ \t]*#/ && $2 == "/usr") { print $4; }}' /etc/fstab)
	
if [[ "$usrfs" == nfs* || "$usropts" =~ _r?netdev ]] ; then
	exit 1
fi

Note that I changed how filesystem options are gathered. I think that grepping /etc/mtab for _netdev is useless, that option is never there. It is only mentioned in /etc/fstab.

Reassigning to initscripts.

PS: just adding systemctl show --property=RequiredBy -- usr.mount | grep -q 'remote-fs.target' && exit 1 wasn't enough because when non-root filesystem is mounted already from initrd is actually RequiredBy=initrd-root-fs.target

Ack for fixing this. By the way, workaround here is to disable the network service completely and use NM.

diff --git a/rc.d/init.d/network b/rc.d/init.d/network
index 541a400..7d765fd 100755
--- a/rc.d/init.d/network
+++ b/rc.d/init.d/network
@@ -165,7 +165,7 @@ case "$1" in
         rootfs=$(awk '{ if ($1 !~ /^[ \t]*#/ && $2 == "/" && $3 != "rootfs") { print $3; }}' /proc/mounts)
         rootopts=$(awk '{ if ($1 !~ /^[ \t]*#/ && $2 == "/") { print $4; }}' /etc/mtab)
        
-       if [[ "$rootfs" == nfs* || "$rootopts" =~ _r?netdev ]] || systemctl show --property=RequiredBy -- -.mount | grep -q 'remote-fs.target' ; then
+       if [[ "$rootfs" == nfs* || "$rootopts" =~ _r?netdev ]] || systemctl show --property=RequiredBy -- -.mount | grep -q 'remote-fs.target' || systemctl show --property=RequiredBy -- usr.mount | grep -q 'remote-fs.target' ; then
                net_log $"rootfs is on network filesystem, leaving network up"
                exit 1
        fi

After the dicussion of systemd and dracut developers, it was decided to keep the functionality in initscripts, and the issue will be fixed in dracut:
https://github.com/fedora-sysv/initscripts/pull/94 (BZ #1446171 has been cloned)


On the initscripts side, the patch for this is already present as a result of 9.70-sync (BZ #1392766):
https://github.com/fedora-sysv/initscripts/commit/0649ea591e8d95415847da3ceeb4c2ba49d01248#diff-29b1f2fa45d29ec13422684108bd12e6R165

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2017:2286