 - Fix an unlocked call to GETATTR by slightly shuffling the code in    ffs_snapshot() around.  - Acquire the interlock before releasing the mntvnode_mtx.  Use the    interlock to protect v_usecount access.
 - Fix an unlocked call to GETATTR by slightly shuffling the code in
   ffs_snapshot() around.
 - Acquire the interlock before releasing the mntvnode_mtx.  Use the
   interlock to protect v_usecount access.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase