on error returns paths with parent still locked, which would
cause 'locking against myself' panic with nonrecursive lock
fixes problem where invalid share name would cause a panic
via smb_sm_lookup() -> smb_share_put()
many thanks to Matthias Drochner for pointing out easy way how to
trigger this problem
incorrectly bombed when the exclusive lock was help by different process
(*yuck*)
lockmgr() checks for 'locking against myself' type of locking problems itself,
so no need to do any additional checks
malloc types into a structure, a pointer to which is passed around,
instead of an int constant. Allow the limit to be adjusted when the
malloc type is defined, or with a function call, as suggested by
Jonathan Stone.
martin