Thanks for helping me out. Here's an update on my system.
> How long have you had the filesystem? Was it likely created with the
> mkfs.btrfs from btrfs-progs v4.1.1 (July, 2015) as I suspect?
Unfortunately, I do not remember exactly when I created the
filesystem, but I know that it was created
I am currently running btrfs on a 2TB GPT drive. The drive is working
fine, still mounts correctly, and I have experienced no data
corruption. Whenever I run "btrfs check" on the drive, it returns
100,000+ messages stating "bad extent [###, ###), type mismatch with
chunk". Whenever I try to run "bt