One way to see how far you've synced is to inspect the output of ./lotus sync wait
"inspection-cid" is the cid of the block header at inspection-epoch, the epoch whose parent state you want to validate.
./lotus chain head
to get your node's current head if inspection-epoch is head height. A list of cids is output, copy one of them../lotus chain list --height=<inspection-epoch> --count=1
if head is above inspection epoch. A list of cid to miner mappings is output, copy one of them.
Navigate to https://filfox.info/en/tipset/<inspection-height>
If inspection-height is not simply head height there could be a null block at this height and you will need to try another epoch
You need to do this so that ent can get access to the lotus datastore.
ent info roots <inspection-cid> 1
Note this will take a few seconds. It will output Epoch <epoch>: <state-root>
ent validate v2 <state-root> <epoch>
Note this can take several minutes. Depending on hardware and current state size > 10 minutes