Hi, Long story short: I''ve got btrfs raid10 six disk array plus 2 other disks just having a "normal setup" btrfs filesystems. Everything was running happily under linux 3.5 and 3.7. 3.5 was a stock ubuntu kernel, 3.7 was "slightly less stock" ubuntu kernel. Now I''ve upgraded my box to 3.8 and none of btrfs file systems mounts any more. I got open_ctree errors every time I try to mount those. When I reboot system choosing old kernel from grub - everything runs smooth again. Was there any "on disk format" change or compatibility change?. Some kernel.log output: [ 13.517952] device fsid 9415cddb-e3b8-4977-804c-369553a7eda7 devid 4 transid 111130 /dev/sdh1 [ 13.518535] btrfs: disk space caching is enabled [ 13.518773] btrfs: failed to read the system array on sdh1 [ 13.523175] btrfs: open_ctree failed -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html