very similar to the issue with nfs41_open_state, an abandoned upcall could outlive its mount. to prevent their nfs41_root from being freed, upcalls need to hold a reference until they're finished. this also keeps all of its clients/sessions/rpc connections alive
Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>
in handle_mount(), the call to nfs41_lookup() requires a mutable nfs41_abs_path because it can change on referrals, so make a copy for it
removed unused fields in struct nfs41_root and related arguments to nfs41_root_create()
Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>
