RT-3.10.6_p3 fails to boot: home.mount mounting timed out

[Light <sgsdxzy@xxxxxxxxx>]

 I am trying to build a RT kernel, however it cannot boot because it 
cannot mount /home, which is a subvolume of btrfs.  This is the entry of 
it in /etc/fstab:

/dev/sda3    /home    btrfs 
subvol=gentoohome,defaults,compress=lzo,autodefrag 0 2

I copyed my .config from a working mainline 3.10 kernel(which is able to 
boot) and used "make oldconfig". The resulting config file is almost the 
same with mainline one: I only changed IO scheduler from BFQ(from gentoo 
patchset) to deadline, without even enabling CONFIG_PREEMPT_RT. However 
the RT kernel just cannot boot.

 Could someone help me figure it out? I bought a new recording device 
and need low latency audio system. Thanks!

The attached file includes .config for RT kernel and the working 
mainline kernel, and the boot log of one failed boot.

Attachment: RT.tar.bz2
Description: application/bzip