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.
Created attachment 1008960[details]
Screenshot of the debug log
I managed to debug this a bit and ran the mount command manually with LIBMOUNT_DEBUG=0xffff. mount(2) syscall is what actuall hangs.
My system hangs in the same way so suspect this is a BTRFS mount bug of some kind. I think it's kernel related, as it works perfectly for me with 3.18.7-100 but fails with 3.18.9-100 or 3.19.3-100.