Couldn't create snapshot after rolling back.

After Snapper rollback sometime ago, I deleted its new made snapshots during the rollback. And the second time I met error in rollback (the default subvolume is missing), I found the solution with --ambit classic, then the new problem comes. Snapper couldn’t create new snapshot, tells me:

Failed to create new snapshot:
.snapshots is not a btrfs subvolume; caused by 3 sender=: -> dest=: serial= reply_serial= path=; interface=; member= error_name=error.io_error

Can i fix this?

Show output of

btrfs subvolume list /
btrfs subvolume get-default /
cat /etc/fstab
Hamu:~ # btrfs subvolume list /
ID 256 gen 27324 top level 5 path @
ID 258 gen 27837 top level 256 path @/var
ID 259 gen 27338 top level 256 path @/usr/local
ID 260 gen 27837 top level 256 path @/tmp
ID 261 gen 27370 top level 256 path @/srv
ID 262 gen 27837 top level 256 path @/root
ID 263 gen 60 top level 256 path @/opt
ID 270 gen 27396 top level 256 path @/.snapshots
ID 696 gen 27837 top level 270 path @/.snapshots/196/snapshot
Hamu:~ # btrfs subvolume get-default /
ID 696 gen 27837 top level 270 path @/.snapshots/196/snapshot
Hamu:~ # cat /etc/fstab
/dev/havol/ganvo                           /           btrfs  defaults             0  0
/dev/havol/ganvo                           /var        btrfs  subvol=/@/var        0  0
/dev/havol/ganvo                           /usr/local  btrfs  subvol=/@/usr/local  0  0
/dev/havol/ganvo                           /tmp        btrfs  subvol=/@/tmp        0  0
/dev/havol/ganvo                           /srv        btrfs  subvol=/@/srv        0  0
/dev/havol/ganvo                           /root       btrfs  subvol=/@/root       0  0
/dev/havol/ganvo                           /opt        btrfs  subvol=/@/opt        0  0
/dev/havol/hme                             /home       btrfs  defaults             0  0
UUID=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX  /boot       ext4   data=ordered         0  2
UUID=XXXXXXXXXXXXXXXX                  /boot/efi   vfat   utf8                 0  2

/.snapshots mount point is missing. Add

/dev/havol/ganvo                           /.snapshots       btrfs  subvol=/@/.snapshots     0  0

to /etc/fstab, mount it and try snapper again. Check that /.snapshots mount point itself exists.

Creating snapshot is working now, you save my time, love you! So later can I delete the first snapshot and have no errer occurd when rolling back?

What is the first snapshot? Rolling back to what exactly?

You must have a base snapshot. The differences of all other shots is measured from there.

It is named “writabe copy #” is my first snapshot right now, if I delete it, rolling back didn’t work last time.

For example, if there are 2 snapshots left, which one is the base snapshot.

I am not staying behind your shoulder so I do not see what you are seeing.