btrfs raid1 still recognized after being overwritten by md raid1

["J. David Beutel" <list@getsu.com>]

I created an md raid1 on partitions that had a btrfs raid1, but btrfs is 
still recognized on one of those partitions.  (Is it finding some 
left-over, redundant metadata?)  I'm concerned this will confuse me or 
btrfs in the future.  How should I fix this?

Details:  after installing on btrfs for the first time, I created a 
btrfs raid1 in Fedora 13 on sda7 sdb7.  Then, while reinstalling Fedora 
13 from DVD, I created an md raid1 on those partitions, containing / 
type ext4.  After booting onto that /, btrfs is still recognized on 
sda7, but sda7 is also in md7, which is mounted on / as type ext4:

[root@pikake jdb]# cat /proc/mdstat
Personalities : [raid1]
md127 : active (auto-read-only) raid1 sdb5[1] sda5[0]
       204788 blocks super 1.0 [2/2] [UU]

md8 : active raid1 sda8[0] sdb8[1]
       218100 blocks super 1.0 [2/2] [UU]

md7 : active raid1 sda7[0] sdb7[1]
       48820156 blocks super 1.1 [2/2] [UU]
       bitmap: 1/1 pages [4KB], 65536KB chunk

md3 : active raid1 sda3[0] sdb3[1]
       12287936 blocks [2/2] [UU]

unused devices: <none>
[root@pikake jdb]# btrfs-show
failed to read /dev/sdf
failed to read /dev/sde
failed to read /dev/sdd
failed to read /dev/sdc
failed to read /dev/sr0
Label: none  uuid: 3257ab1a-45de-43d3-bd84-a01ca93d0296
     Total devices 1 FS bytes used 7.71GB
     devid    1 size 48.83GB used 14.54GB path /dev/sda6

Label: none  uuid: c25ab51a-9fec-4e67-a5d8-4968e7d2e5e8
     Total devices 2 FS bytes used 7.69GB
     devid    1 size 46.56GB used 11.40GB path /dev/sda7
     *** Some devices missing

Btrfs Btrfs v0.19
[root@pikake jdb]# mount
/dev/md7 on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/dev/md8 on /boot type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
gvfs-fuse-daemon on /home/jdb/.gvfs type fuse.gvfs-fuse-daemon 
(rw,nosuid,nodev,user=jdb)