Persistent Reserve questions about ALL_TG_PT bit

Gerry.Houlder at seagate.com Gerry.Houlder at seagate.com
Wed Apr 16 12:07:23 PDT 2008


* From the T10 Reflector (t10 at t10.org), posted by:
* Gerry.Houlder at seagate.com
*
(1) If an initiator sends PR OUT command with REGISTER or REGISTER AND
IGNORE EXISTING KEY service action and the ALL_TG_PT bit set, what should
be done if that initiator is already registered on one or more other ports?
There are words added for SPEC_I_PT bit case that require CHECK CONDITION
status and the register operation is aborted but it is unclear if this
result should occur for ALL_TG_PT case as well, or if the new registration
should override the existing registration.
(2) Question 1 is even tricker if the existing registration on another port
also happens to hold a reservation. Overriding such a registration with a
new key (for instance) could affect the reservation.
(3) Doing a REGISTER with the new key set to zero is an unregister
operation. If the ALL_TG_PT bit is set, are all ports unregistered or is
this an illegal operation?
(4) Question 3 is even trickier if the registration on another port is a
reservation holder. If removing the registration would be allowed, this
would also remove a reservation that is owned by another port. Should this
be allowed or is this an illegal operation?
It seems like we have a precedent set for the SPEC_I_PT bit that makes this
bit illegal for unregister operations (i.e., an unregister can only
unregister its own I_T nexus but not any others). This precedent also makes
it illegal to create another registration (e.g., for another initiator) if
such a registration already exists. Is there any reason not to apply these
same rules to the ALL_TG_PT bit?
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