RAID 1 with no data on it when accidentally switched HDD

[Ingo Ebel <ingo.ebel@ingoebel.de>]

Hi,

I'm not sure whether it's a bug in btrfs or my distro but I discovered 
an odd behavior today.

My Setup:

* Btrfs v3.12+20131125
* /dev/sda – Boot OS - opensuse 13.1
* Btrfs RAID 1 on /dev/sdb1 and /dev/sdc1

I added an extra HDD with an other OS and Data on it witch accidentally 
became /dev/sdc.

Btrfs got mounted at boot time without any complains but in the main 
volume was empty.
Some subvolumes still had Data.

I took the extra HDD out but still no data in the Btrfs main volume. 
Bfrfsck reported no error.
Some Parts on the (accidentally) /dev/sdc are now corrupt.

I would expect that btrfs would throw an error when getting in the kind 
of scenario.

Regards

Ingo