Comment 14 for bug 1559723

The underlying md-raid (mirroring) is fine. So according to md-raid status, there's nothing wrong with the mirrored partitions:

cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sda3[0] sdb3[1]
      2929833792 blocks super 1.2 [2/2] [UU]

Basically that means, if there is no issue with LUKS (and I don't see any), then the btrfs-balance on a full disk led to the ro-mounted, presumably corrupted file system.

I'll try to check the raid integrity, which might take a day or two.