libata: SATL error processing: unrecovered read error

libata: SATL error processing: unrecovered read error

[Douglas Gilbert]

While looking at an eSATA connected external disk with
a medium error, this sense data appeared:

     READ cdb: 28 00 96 4a 7a d1 00 00 01 00
       duration=2816 ms
READ:  Descriptor format, current;  Sense key: Medium Error
  Additional sense: Unrecovered read error - auto reallocate failed
   Descriptor type: Information
     0x00000000964a7ad1
  Raw sense data (in hex):
         72 03 11 04 00 00 00 0c  00 0a 80 00 00 00 00 00
         96 4a 7a d1

That is pretty close to what I was expecting to see. If anything
there is too much information. That "Unrecovered read error -
auto reallocate failed" [asc/asq: 11h/04h] should just be
"Unrecovered read error" [asc/asq: 11h/0h]. See sat2r09.pdf table
105 or sat3r00.pdf table 105.

The problem seems to be in libata's SATL code in the sense_table[]
in ata_to_sense_error() in libata-scsi.c . Looks like some other
entries in that sense_table need adjusting as well to align them
to SAT's table 105.

Also it is good to have a reference comment as sense_data[]
does in lk 2.6.35:
   /* Based on the 3ware driver translation table */

but this would be better (if it did comply):
   /* Based on table 105 in SAT-2 rev 9 */

Doug Gilbert

Re: libata: SATL error processing: unrecovered read error

[Jeff Garzik]

On 09/05/2010 11:57 AM, Douglas Gilbert wrote:
> While looking at an eSATA connected external disk with
> a medium error, this sense data appeared:
>
> READ cdb: 28 00 96 4a 7a d1 00 00 01 00
> duration=2816 ms
> READ: Descriptor format, current; Sense key: Medium Error
> Additional sense: Unrecovered read error - auto reallocate failed
> Descriptor type: Information
> 0x00000000964a7ad1
> Raw sense data (in hex):
> 72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00
> 96 4a 7a d1
>
> That is pretty close to what I was expecting to see. If anything
> there is too much information. That "Unrecovered read error -
> auto reallocate failed" [asc/asq: 11h/04h] should just be
> "Unrecovered read error" [asc/asq: 11h/0h]. See sat2r09.pdf table
> 105 or sat3r00.pdf table 105.

If any auto-reallocate occurred on the drive's part, it definitely 
failed at that point.  And auto-reallocate is a possibility.

11h/04h seems to more accurately describe the situation.

	Jeff

Re: libata: SATL error processing: unrecovered read error

[Douglas Gilbert]

On 10-09-17 02:31 PM, Jeff Garzik wrote:
> On 09/05/2010 11:57 AM, Douglas Gilbert wrote:
>> While looking at an eSATA connected external disk with
>> a medium error, this sense data appeared:
>>
>> READ cdb: 28 00 96 4a 7a d1 00 00 01 00
>> duration=2816 ms
>> READ: Descriptor format, current; Sense key: Medium Error
>> Additional sense: Unrecovered read error - auto reallocate failed
>> Descriptor type: Information
>> 0x00000000964a7ad1
>> Raw sense data (in hex):
>> 72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00
>> 96 4a 7a d1
>>
>> That is pretty close to what I was expecting to see. If anything
>> there is too much information. That "Unrecovered read error -
>> auto reallocate failed" [asc/asq: 11h/04h] should just be
>> "Unrecovered read error" [asc/asq: 11h/0h]. See sat2r09.pdf table
>> 105 or sat3r00.pdf table 105.
>
> If any auto-reallocate occurred on the drive's part, it definitely
> failed at that point. And auto-reallocate is a possibility.
>
> 11h/04h seems to more accurately describe the situation.

Usually if you are implementing a SCSI device (lu) there
is some latitude in asc/asq codes. However for a SAT layer
they state exactly how to translate ATA errors.

There is one published SAT standard (ANSI INCITS 431-2007)
and there will soon be another one (SAT-2). The compliant
response is asc/asq: 11h/0h since in t10 documents additional
sense matches by string which is shown in upper case.


BTW I never understood what asc/asq 11h/04h was about,
auto-reallocate is something that should be attempted
on a _recovered_ read error. And that in turn might fail
if the disk had run out of spare blocks. So in a contorted
sort of way, perhaps that is what "Unrecovered read error -
auto reallocate failed" means!?  If so, you are most
likely incorrect on that count as well.

Doug Gilbert

Re: libata: SATL error processing: unrecovered read error

[Jeff Garzik]

On 09/17/2010 03:26 PM, Douglas Gilbert wrote:
> On 10-09-17 02:31 PM, Jeff Garzik wrote:
>> On 09/05/2010 11:57 AM, Douglas Gilbert wrote:
>>> While looking at an eSATA connected external disk with
>>> a medium error, this sense data appeared:
>>>
>>> READ cdb: 28 00 96 4a 7a d1 00 00 01 00
>>> duration=2816 ms
>>> READ: Descriptor format, current; Sense key: Medium Error
>>> Additional sense: Unrecovered read error - auto reallocate failed
>>> Descriptor type: Information
>>> 0x00000000964a7ad1
>>> Raw sense data (in hex):
>>> 72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00
>>> 96 4a 7a d1
>>>
>>> That is pretty close to what I was expecting to see. If anything
>>> there is too much information. That "Unrecovered read error -
>>> auto reallocate failed" [asc/asq: 11h/04h] should just be
>>> "Unrecovered read error" [asc/asq: 11h/0h]. See sat2r09.pdf table
>>> 105 or sat3r00.pdf table 105.
>>
>> If any auto-reallocate occurred on the drive's part, it definitely
>> failed at that point. And auto-reallocate is a possibility.
>>
>> 11h/04h seems to more accurately describe the situation.
>
> Usually if you are implementing a SCSI device (lu) there
> is some latitude in asc/asq codes. However for a SAT layer
> they state exactly how to translate ATA errors.
>
> There is one published SAT standard (ANSI INCITS 431-2007)
> and there will soon be another one (SAT-2). The compliant
> response is asc/asq: 11h/0h since in t10 documents additional
> sense matches by string which is shown in upper case.

Fair enough.  Wanna write a patch?  :)


> BTW I never understood what asc/asq 11h/04h was about,
> auto-reallocate is something that should be attempted
> on a _recovered_ read error. And that in turn might fail
> if the disk had run out of spare blocks. So in a contorted
> sort of way, perhaps that is what "Unrecovered read error -
> auto reallocate failed" means!? If so, you are most
> likely incorrect on that count as well.

The ATA disk hits an unrecovered read error, which by virtue of 
operation implies auto reallocate failed.  What's going on inside seems 
to match the error text quite closely.

	Jeff