Comment # 2 on bug 980962 from Uli Wortmann

(In reply to Arvin Schnell from comment #1)
> Unfortunately the report is not entirely clear to me.
> 
> "reports snapshot 475 as the current snapshot. Upon inspection of the actual
> file content, snapshot 489 is indeed mounted as current."
> 
> While doing so you booted the default subvolume and did also not change the
> default subvolume (e.g. via a rollback)?
> 
> How did you do the inspection?

OK. let me see of I can clarify this:

"snapper list" gives the current list of snapshots (465 to 489)
"btrfs sub get-default /" returns that snapshot id 475 is the current snapshot

Now, I place a text-file named "snapper_test_May_26th.txt" on the root volume
and create a new snapshot (490)

After rebooting, I go to .snapshots/490 and the the above file is there as
expected. However "btrfs sub get-default" still points to id 475.

Investigating /.snapshots/475/snapshot shows that "snapper_test_May_26th.txt"
is present there as well. So I conclude that 475 and 490 are identical.
Unfortunately, this prevents the cleanup algorithm from deleting 475 and any
other snapshot with an id > 475.

The above behavior only occurs after you boot to a previous snapshot and do a
subsequent rollback (in this case to id 475). Any subsequent snapshots will
then point to id 475 and create the above problem with the cleanup algorithm.

Happy to help, don't hesitate to get in touch

Uli