I agree the target appears incorrect.
 
This does assume that the PR IN (Read Full Status) specifies
an allocation length long enough to return the data.  Since the
Read Reservations did, I assume the Read Full did as well,
although it is possible that the initiator saw the Read Reservations
response with the additional length of 0, and just used that as
the allocation length for the Read Full Status command (and so,
the 0 length returned data is what the initiator asked for).
 
    Fred Knight
    Network Appliance

From: David Peterson [mailto:dpeterso@brocade.com]
Sent: Tuesday, February 26, 2008 1:42 PM
To: t10@t10.org
Subject: Persistent Reserve In: READ FULL STATUS response

From a trace I see the following:

 

PR In (Read Reservations)

-          PRgeneration = 00 00 00 00h

-          Additional Length = 00 00 00 00h

Good Status

 

* Given this response data there is no reservation held

  

PR In (Read Full Status)

-          no data returned

Good Status

 

* SPC-4 5.6.6.4 states:

An application client may send a PERSISTENT RESERVE IN command with READ FULL STATUS service action to receive all information about registrations and the persistent reservation, if any.

 

In response to a PERSISTENT RESERVE IN command with READ FULL STATUS service action the device server shall report the current PRgeneration value (see 6.13.2) and, for every I_T nexus that is currently registered, the

following information:

a) The registered reservation key;

b) Whether the I_T nexus is a persistent reservation holder;

c) If the I_T nexus is a persistent reservation holder, the scope and type of the persistent reservation;

d) The relative target port identifier identifying the target port of the I_T nexus; and

e) A TransportID identifying the initiator port of the I_T nexus.

 

My understanding is that although no reservation is held, the PRgeneration value (00 00 00 00h in this case) shall be returned and the Additional Length field shall be set to zero.

 

Appears this particular target implementation is not following the standard per Service Action=Read Full Status in that it simply returns no data if no reservation is held.

 

Comments?

 

…Dave