[pnfs] what error should be returned to an impatient client?

[Benny Halevy]

while reviewing the sessions text in draft-10 I realized that
it is not clear what error the server should return if the
client sent a new request on a slot that's still in use.

In the currently linux implementation (in Andy's latest patches)
nfsd4_sequence() just allows that
	status = nfs_ok;
	if (nfs41_get_slot_state(slot) != NFS4_SLOT_AVAILABLE)
		goto out;
...
out:
	dprintk("%s returns %d\n", __FUNCTION__, status);
	nfs4_unlock_state();
	return status;

I suggest returning NFS4ERR_BADSLOT or add a new error code NFS4ERR_BUSYSLOT
(other alternatives could be NFS4ERR_INVALID or NFS4ERR_SEQ_MISORDERED).

Benny