Subject: [Ips] Pending R2T's at the initiator and initiator issuing "abort task"

From: "Prasanna Aithal" <[email-masked]>
Date: Mon, 3 Dec 2007 22:29:31 -0800

RFC 3720, Section 10.5.1 says:
 
"For ABORT TASK SET and CLEAR TASK SET, the issuing initiator MUST
continue to respond to all valid target transfer tags (received via
R2T, Text Response, NOP-In, or SCSI Data-In PDUs) related to the
affected task set, even after issuing the task management request.
The issuing initiator SHOULD however terminate (i.e., by setting the
F-bit to 1) these response sequences as quickly as possible. The
target on its part MUST wait for responses on all affected target
transfer tags before acting on either of these two task management
requests. In case all or part of the response sequence is not
received (due to digest errors) for a valid TTT, the target MAY treat
it as a case of within-command error recovery class (see Section
6.1.4.1 Recovery Within-command) if it is supporting
ErrorRecoveryLevel >= 1, or alternatively may drop the connection to
complete the requested task set function."

What is expected of the initiators in case of "abort task"?. Does the
responding to "all valid target tags" apply to "abort task" also?.

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From: [email-masked]
Date: Tue, 4 Dec 2007 10:04:56 -0500

Prasanna,

> complete the requested task set function."

Please be aware that the above text was modified by Section 4 of
RFC 5048, although those modifications do not affect what is being
 
> responding to "all valid target tags" apply to "abort task" also?.

No, ABORT TASK can only be used by an initiator to abort one of its
own commands - it is required to be issued on the same TCP connection
as the command to be aborted:

   If the connection is still active (it is not undergoing an implicit
   or explicit logout), ABORT TASK MUST be issued on the same connection
   to which the task to be aborted is allegiant at the time the Task
   Management Request is issued.

This avoids any need to complete outstanding transfers because
the ABORT TASK request is synchronized with those transfers (which
also have to be on the same connection).

Thanks,
--David
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David L. Black, Distinguished Engineer
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
[email-masked]        Mobile: +1 (978) 394-7754
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