On Tue, Aug 3, 2021 at 1:51 AM Sreyan Chakravarty <sreyan32(a)gmail.com> wrote:
Hi,
I am faced with a strange problem. I have a BTRFS snapshot that I want to delete but just
can't.
So I always manipulate BTRFS snapshots from a live-cd environment which I setup using the
following commands:
sudo cryptsetup open /dev/sda3 dm-crypt
<<GIVE PASSWORD>>
sudo mount /dev/mapper/dm-crypt /mnt
Now I can query the snapshots:
$ sudo btrfs subvolume list /mnt
ID 448 gen 235989 top level 5 path root
ID 449 gen 0 top level 5 path before_live_cd_exp
I want to delete the snapshot "before_live_cd_exp", which I am unable to do:
$ sudo btrfs subvolume delete /mnt/before_live_cd_exp/
ERROR: Not a Btrfs subvolume: Invalid argument
What does it mean it's not a Btrfs subvolume ? It was picked up by the list command.
I also tried via the subvolid:
$ sudo btrfs subvolume delete --subvolid 449 /mnt
Delete subvolume (no-commit): '/mnt/before_live_cd_exp'
ERROR: Could not destroy subvolume/snapshot: No such file or directory
What messages appear in dmesg and coincide with the failed command?
I haven't heard of anyone being unable to delete snapshots before. But
also suspicious about this particular snapshot (which I also haven't
ever seen) is its generation is 0. Even brand new subvolumes on a
brand new file system have non-zero generation.
This is even weirder since as you can clearly see the directory
exists in the given path.
Any suggestions on what is going wrong ?
I should tell you that a while back I had a huge BTRFS file system crash, and it took a
lot of targeted help from the community to get my system to boot.
This could be a side effect of an incomplete repair.
--
Chris Murphy