Query regarding response of UNMAP command
munjal_mistry at mentor.com
Thu Feb 19 03:18:28 PST 2015
* From the T10 Reflector (t10 at t10.org), posted by:
* Munjal Mistry <munjal_mistry at mentor.com>
I have a query regarding the response for UNMAP command when there is
mismatch of "PARAMETER LIST LENGTH" (field of UNMAP command) with "UNMAP
DATA LENGTH" or "UNMAP BLOCK DESCRIPTOR DATA LENGTH" (fields of unmap
parameter list). Here, Storage device is thin provisioning.
For example, host wants to transfer single block descriptor with UNMAP
command. In this cases following values shall be driven:
PARAMETER LIST LENGTH= 'h18 (24),
UNMAP DATA LENGTH= 'h16 (22),
UNMAP BLOCK DESCRIPTOR DATA LENGTH= 'h10 (16).
Here, if host transmits other than 'h16 value for UNMAP DATA LENGTH
field or other than 'h10 for UNMAP BLOCK DESCRIPTOR DATA LENGTH field,
then which of the following behavior of device is correct:
(1) Device ignores it's value and unmap the logical blocks described
with UNMAP block descriptor and sends GOOD response.
(2) Device ignores it's value and unmap the logical blocks described
with UNMAP block descriptor and sends failure response.
(3) Device terminates the command and sends failure response.
If device sends the failure response, as per the 2nd and 3rd behavior
then what would be the possible status, ASC and ASCQ for failure?
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