"some devices missing" after scrub and btrfs upgrade.

I'm looking for advice on the best way to proceed. I have a two-disk raid 1 btrfs root file system into which the box boots. The file system became corrupted to the point where I was unable to boot into it. Using my rescue system I ran scrub which seemed to sort out the problem. I can now boot into the raid and the data appears to be intact. I have now upgraded to kernel version 3.19.1 with the accompanying latest btrfs-progs. Even though the data still appears to be accessible, when I run "btrfs fi show" only one disk is listed along with the message "some devices missing".