Re: iSCSI: RefCmdSN != CmdSN

["Mallikarjun C." <cbm@rose.hp.com>]

It isn't quite an implementation issue.  The spec *requires* 
the target to look at RefCmdSN - and that's only when the 
ITT doesn't point to a valid task.  

I believe we should have some text that specifies the target
is required to look at RefCmdSN.
--
Mallikarjun

Mallikarjun Chadalapaka
Networked Storage Architecture
Network Storage Solutions Organization
Hewlett-Packard MS 5668 
Roseville CA 95747


----- Original Message ----- 
From: "Eddy Quicksall" <Eddy_Quicksall@ivivity.com>
To: "Mallikarjun C." <cbm@rose.hp.com>
Cc: "ips@ece. cmu. edu (E-mail)" <ips@ece.cmu.edu>
Sent: Friday, March 01, 2002 6:22 AM
Subject: RE: iSCSI: RefCmdSN != CmdSN


> Yes, but I don't think the statement "Targets however must consider ..." is
> necessary because the initiator must always make them consistent and it is a
> target implementation issue as to which it actually uses.
> 
> 
> Eddy
> 
> -----Original Message-----
> From: Mallikarjun C. [mailto:cbm@rose.hp.com]
> Sent: Thursday, February 28, 2002 8:47 PM
> To: ips@ece. cmu. edu (E-mail)
> Subject: Re: iSCSI: RefCmdSN != CmdSN
> 
> 
> Eddy,
> 
> I agree that targets don't have to check both always, only when it
> is needed.
> 
> The intended role of RefCmdSN is to help identify the right command
> when the command to be aborted had not arrived - the command
> could be lost due to digest errors or as part of connection failure.
> So I think the quoted text should be rephrased to:
> 
> Section 9.5.4
> For the ABORT TASK function, initiators MUST always set this to the
> CmdSN of the task identified by the Initiator Task Tag field.  Targets
> however
> must consider the field valid only when the task indicated by the Initiator
> Task Tag field does not exist.
> 
> Section 9.6.1
> For the ABORT TASK function,
>     a) if the ITT identifies a valid task leading to a successful
> termination,
>         targets must return the "Function complete" response.
>     b)if the ITT does not identify an existing task but if the CmdSN
> indicated
>        by the RefCmdSN field in the task management function request is
> within
>        the valid CmdSN window, targets must consider the CmdSN received
>        and return the "Function complete" response.
>    c) if the ITT does not identify an existing task and if the CmdSN
> indicated
>        by the RefCmdSN field in the task management function request is
> outside
>        the valid CmdSN window, targets must return the "Task does not exist"
> response.
> 
> Comments?
> --
> Mallikarjun
> 
> Mallikarjun Chadalapaka
> Networked Storage Architecture
> Network Storage Solutions Organization
> Hewlett-Packard MS 5668
> Roseville CA 95747
> 
> ----- Original Message -----
> From: "Eddy Quicksall" <Eddy_Quicksall@ivivity.com>
> To: "ips@ece. cmu. edu (E-mail)" <ips@ece.cmu.edu>
> Sent: Thursday, February 28, 2002 4:46 PM
> Subject: iSCSI: RefCmdSN != CmdSN
> 
> 
> > Is there a reason that this check is mandated? Is there a case where this
> > can happen with bug free code?
> >
> >  If RefCmdSN does not match the CmdSN of the command to be aborted at the
> >  target, the abort action MUST NOT be performed and the response MUST
> >  be 'function rejected'.
> >
> >
> > Eddy_Quicksall@iVivity.com
> >
>