Description of problem:
Boot hangs on "A start job is running on /sysroot". It happens on both my vm and my host, both of them having F21 and a btrfs root filesystem. The job eventually times out ofter 4m 40s. I don't know how to provide any more information, as dracut drops me into pretty unusable shell (no /etc/fstab, no network, no disk access).


Version-Release number of selected component (if applicable):
systemd-216-21.fc21.x86_64
dracut-038-33.git20141216.fc21.x86_64


How reproducible:
Sometimes, after recent update


Steps to Reproduce:
1. Have a latest F21 installation with btrfs root.
2. Boot.


Actual results:
Boot hangs.


Expected results:
Computer boots normally.


Additional info:
On my physical computer, the problem mysteriously disappeared after undocking it and forcing a poweroff with the poweroff button. On the vm, the hang still happens.