Everyone:
For 2.1, we implemented our new locking service. This means that all assets uploaded into a user's sandbox are auto-locked, just as is any edited items in the web client or CIFS.
The result, however, was a significant performance degradation as locks are taken on assets. That is the issue noted by Kev. We are doing some serious performance profiling and tuning presently for our next Community drop.
As Kev notes, if you've mounted CIFS as admin you can drag-and-drop directly into Staging, where created assets do not have locks explicitly taken. This is a temporary workaround until we can correct this performance issue.
If you upload an expanded war via CIFS into Staging instead of a user's sandbox either via CIFS or the web client, you'll have anywhere between a 25 and 30x diff in performance. For example, a WAR file that will take 15s using the workaround will take ~18m because of locking.
We will keep you posted on this.
Kevin