Task Management question

Elliott, Robert Robert.Elliott at COMPAQ.com
Tue Apr 2 12:30:05 PST 2002


* From the T10 Reflector (t10 at t10.org), posted by:
* "Elliott, Robert" <Robert.Elliott at COMPAQ.com>
*
Comments below...

> -----Original Message-----
> From: Ken Craig [mailto:kcraig at istor-networks.com]
> Sent: Tuesday, April 02, 2002 1:00 PM
> Subject: Task Management question
> 
> In SAM-2, revision 22, Section 6, there is a paragraph concerning
> the effects that ACCESS CONTROLS have on task management
> requests yet I can't find anything anywhere concerning task
> management requests and RESERVE/RELEASE or PERSISTENT
> RESERVE/RELEASE.  My question is "Is it really true that
> task management requests are processed without any regard to
> reservation status?"  

Yes.

> If so I am confused about why Initiators that
> normally would not be allowed access to a Logical Unit are allowed
> to affect the task sets in that Logical Unit.  In relation to ABORT
> TASK, ABORT TASK SET and CLEAR ACA and ACCESS CONTROLS how
> can all the functionality that these service actions represent be
> bypassed by an initiator with no access rights to a Logical Unit?

Reservations are for cooperating initiators sharing
a logical unit.  They shouldn't send CLEAR TASK SET,
LOGICAL UNIT RESET, or TARGET RESET (the functions that 
may affect other initiators' tasks) without good reason. 

Access controls are for non-cooperating initiators sharing
a target but not necessarily sharing logical units.  

Access controls prevents TARGET RESET from affecting 
logical units being used by other initiators.

An initiator must have access rights to a logical unit 
to run a CLEAR TASK SET or LOGICAL UNIT RESET on it;
rogue resets are prevented.

ABORT TASK, ABORT TASK SET, and CLEAR ACA affect only the
initiator sending them, so access controls doesn't change
their behavior.  If the initiator doesn't have access
rights, it also doesn't have any tasks to abort.

---
Rob Elliott, Compaq? Server Storage
Robert.Elliott at compaq.com

 
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