Description of problem:
After migrating my /home from ext4 to btrfs and upgrading the kernel frpom 2.6.25(?) to 2.6.38-0.rc7 I notice oops when there is a high io on the btrfs partition.

Version-Release number of selected component (if applicable):
# rpm -q kernel btrfs-progs
kernel-2.6.37-0.rc5.git2.1.fc15.i686
kernel-2.6.38-0.rc6.git0.1.fc16.i686
kernel-2.6.38-0.rc7.git2.3.fc16.i686
btrfs-progs-0.19-13.fc15.i686
[root@proprietary ~]# uname -a
Linux proprietary.local 2.6.38-0.rc7.git2.3.fc16.i686 #1 SMP Sat Mar 5 00:09:37 UTC 2011 i686 i686 i386 GNU/Linux

How reproducible:
Quite often.

Steps to Reproduce:
1. migrate a ext4 partition (atop a lvm logvol) to btrfs using btrs-convert
2. rsync many files from that partition to an external usb drive (backup ..)
3.
  
Actual results:
the attached oopses appear

Expected results:
No oopses.

Additional info:
The btrfs partition is atop of a logvol (side effect of the migration from ext4 to btrfs).