happens after we've droppped the sessionid_lock, and without holding a
reference on the session; so there's nothing preventing the session
being freed before we get here.
Thanks to Benny Halevy for catching a bug in an earlier version of this
patch.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Acked-by: Benny Halevy <bhalevy@panasas.com>