When were you hitting these ENOSPC errors, and what kernel were you using when you hit them? $ df -h . Filesystem Size Used Avail Use% Mounted on /

When were you hitting these ENOSPC errors, and what kernel were you using when you hit them? $ df -h . Filesystem Size Used Avail Use% Mounted on /dev/dm-1 42G 41G 280M 100% /home $ btrfs fi df . Data, single: total=40.48GiB, used=40.21GiB System, single: total=4.00MiB, used=12.00KiB Metadata, single: total=1.01GiB, used=649.18MiB $ uname -r 3.15.2-hardened As you can see, I've been working with a pretty much full btrfs volume. It used to be TERRIBLE to deal with btrfs in such a situation, but I haven't had an ENOSPC issue in ages.