I'm new to btrfs and I am trying to delete some snapshots I made a few months ago. They're taking up about 20GB of space, and I need that space back.
This seems to list the snapshots:
↪ sudo btrfs subvolume list /
ID 257 gen 82021 top level 5 path @
ID 258 gen 82021 top level 5 path @home
ID 263 gen 81983 top level 5 path @home/.ecryptfs/mlissner/.Private/ECRYPTFS_FNEK_ENCRYPTED.FWa8iOdaTukmNEROkGj4b5OZHZ0bKOqrvAQxu4dgX.2jUELJL22wpV94oU--/ECRYPTFS_FNEK_ENCRYPTED.FWa8iOdaTukmNEROkGj4b5OZHZ0bKOqrvAQxHunTlBS-30iHyukjeY9-EE--/root_post_install_2014-04-29
ID 364 gen 81986 top level 5 path @home/.ecryptfs/mlissner/.Private/ECRYPTFS_FNEK_ENCRYPTED.FWa8iOdaTukmNEROkGj4b5OZHZ0bKOqrvAQxu4dgX.2jUELJL22wpV94oU--/ECRYPTFS_FNEK_ENCRYPTED.FWa8iOdaTukmNEROkGj4b5OZHZ0bKOqrvAQxHunTlBS-30iHyukjeY9-EE--/root_post_install_2014-05-04
ID 376 gen 81996 top level 5 path @home/.ecryptfs/mlissner/.Private/ECRYPTFS_FNEK_ENCRYPTED.FWa8iOdaTukmNEROkGj4b5OZHZ0bKOqrvAQxu4dgX.2jUELJL22wpV94oU--/ECRYPTFS_FNEK_ENCRYPTED.FWa8iOdaTukmNEROkGj4b5OZHZ0bKOqrvAQxHunTlBS-30iHyukjeY9-EE--/root_post_install_2014-05-14
How do I delete them? When I try the obvious thing, I get an error:
↪ sudo btrfs subvolume delete root_post_install_2014-04-29
Delete subvolume '/home/mlissner/.btrfs/snapshots/root_post_install_2014-04-29'
ERROR: cannot delete '/home/mlissner/.btrfs/snapshots/root_post_install_2014-04-29' - Device or resource busy
I'm feeling a bit lost and Googling is revealing no real help. I'm happy to post more information if that will help, but for now, I'm a baffled how to proceed.