"qvm-volume info" lacks revision details on btrfs

According to Volume backup and revert | Qubes OS , if I run qvm-volume info vmname:private , I should be able to see the above list of “Available revisions (for revert)”, where the last item on the list with the largest integer is the most recent snapshot.

However, this is not the case on btrfs. I can only get how many revisions does the volume have, but I cannot get the exact revision version numbers that can be used for reverting.

[augsch@dom0 whonix-gw-16]$ qvm-volume info whonix-gw-16:root
pool               varlibqubes
vid                vm-templates/whonix-gw-16/root
rw                 True
source             
save_on_stop       True
snap_on_start      False
size               21474836480
usage              2338689024
revisions_to_keep  1
ephemeral          False
is_outdated        False
Available revisions (for revert):
  4

So, here’s my question: How can I specify one revision for qvm-volume revert on btrfs? Thanks.

You can’t revert to revision #4?

Thank! I’m such a fool :smile:. I haven’t got accustomed to btrfs’s revision scheme. I thought the revision number should be a long string of chars, like the case on LVM-thin.

I don’t think this is brtfs, I think it’s whonix, my other volumes are using the timestamp format.

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For any file-reflink volume (Btrfs/XFS) it’s always just a low integer like 123 as the revision ID that’s shown in qvm-volume info output ( → PR to clarify the header), although the filename also includes a timestamp:

/var/lib/qubes/appvms/vault/private.img.123@2023-04-05T12:34:56Z
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