Re: [dm-devel] [PATCH 1/1] multipath-tools: Change path checker for IBM IPR devices

[Brian King <brking@linux.vnet.ibm.com>]

On 10/01/2014 07:51 AM, Christoph Hellwig wrote:
> Unfortunately the patch wasn't quite correct - all TEST_UNIT_READY
> commands are sent as BLOCK_PC, so this would basically revert James'
> original fix for the SATL case.
> 
> Am I right to assume you only need the call to scsi_dh->check_sense and
> not the rest of the handling for the multipath path checker?  If that's
> the case something like the patch below sould work:

This would work if we also duplicated the 02/04/02 K/C/Q check in alua_check_sense
handler.

Wendy - can you try my patch below, along with Christoph's latest patch here
and see if that resolves the issue?

Thanks,

Brian

> 
> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
> index 5db8454..399c1c8 100644
> --- a/drivers/scsi/scsi_error.c
> +++ b/drivers/scsi/scsi_error.c
> @@ -459,14 +459,6 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
>  	if (! scsi_command_normalize_sense(scmd, &sshdr))
>  		return FAILED;	/* no valid sense data */
> 
> -	if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
> -		/*
> -		 * nasty: for mid-layer issued TURs, we need to return the
> -		 * actual sense data without any recovery attempt.  For eh
> -		 * issued ones, we need to try to recover and interpret
> -		 */
> -		return SUCCESS;
> -
>  	scsi_report_sense(sdev, &sshdr);
> 
>  	if (scsi_sense_is_deferred(&sshdr))
> @@ -482,6 +474,14 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
>  		/* handler does not care. Drop down to default handling */
>  	}
> 
> +	if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
> +		/*
> +		 * nasty: for mid-layer issued TURs, we need to return the
> +		 * actual sense data without any recovery attempt.  For eh
> +		 * issued ones, we need to try to recover and interpret
> +		 */
> +		return SUCCESS;
> +
>  	/*
>  	 * Previous logic looked for FILEMARK, EOM or ILI which are
>  	 * mainly associated with tapes and returned SUCCESS.
> 



Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
---

 drivers/scsi/device_handler/scsi_dh_alua.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff -puN drivers/scsi/device_handler/scsi_dh_alua.c~alua_allow_restart drivers/scsi/device_handler/scsi_dh_alua.c
--- linux/drivers/scsi/device_handler/scsi_dh_alua.c~alua_allow_restart	2014-10-06 10:19:16.184798305 -0500
+++ linux-bjking1/drivers/scsi/device_handler/scsi_dh_alua.c	2014-10-06 10:20:35.743165951 -0500
@@ -474,6 +474,13 @@ static int alua_check_sense(struct scsi_
 			 * LUN Not Ready -- Offline
 			 */
 			return SUCCESS;
+		if (sdev->allow_restart &&
+		    (sense_hdr->asc == 0x04) && (sense_hdr->ascq == 0x02))
+			/*
+			 * if the device is not started, we need to wake
+			 * the error handler to start the motor
+			 */
+			return FAILED;
 		break;
 	case UNIT_ATTENTION:
 		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
_