Commit 63583cca authored by Hannes Reinecke's avatar Hannes Reinecke Committed by James Bottomley
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[SCSI] Add detailed SCSI I/O errors 



Instead of just passing 'EIO' for any I/O error we should be
notifying the upper layers with more details about the cause
of this error.

Update the possible I/O errors to:

- ENOLINK: Link failure between host and target
- EIO: Retryable I/O error
- EREMOTEIO: Non-retryable I/O error
- EBADE: I/O error restricted to the I_T_L nexus

'Retryable' in this context means that an I/O error _might_ be
restricted to the I_T_L nexus (vulgo: path), so retrying on another
nexus / path might succeed.

'Non-retryable' in general refers to a target failure, so this
error will always be generated regardless of the I_T_L nexus
it was send on.

I/O errors restricted to the I_T_L nexus might be retried
on another nexus / path, but they should _not_ be queued
if no paths are available.

Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent 7a1e9d82

drivers/scsi/scsi_error.c

+17 −7
Original line number Diff line number Diff line
@@ -223,7 +223,7 @@ static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost, 
 * @scmd:	Cmd to have sense checked.

 *

 * Return value:

 * 	SUCCESS or FAILED or NEEDS_RETRY

 *	SUCCESS or FAILED or NEEDS_RETRY or TARGET_ERROR

 *

 * Notes:

 *	When a deferred error is detected the current command has
@@ -326,17 +326,19 @@ static int scsi_check_sense(struct scsi_cmnd *scmd) 
		 */

		return SUCCESS;



		/* these three are not supported */

		/* these are not supported */

	case COPY_ABORTED:

	case VOLUME_OVERFLOW:

	case MISCOMPARE:

		return SUCCESS;

	case BLANK_CHECK:

	case DATA_PROTECT:

		return TARGET_ERROR;



	case MEDIUM_ERROR:

		if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */

		    sshdr.asc == 0x13 || /* AMNF DATA FIELD */

		    sshdr.asc == 0x14) { /* RECORD NOT FOUND */

			return SUCCESS;

			return TARGET_ERROR;

		}

		return NEEDS_RETRY;
@@ -344,11 +346,9 @@ static int scsi_check_sense(struct scsi_cmnd *scmd) 
		if (scmd->device->retry_hwerror)

			return ADD_TO_MLQUEUE;

		else

			return SUCCESS;

			return TARGET_ERROR;



	case ILLEGAL_REQUEST:

	case BLANK_CHECK:

	case DATA_PROTECT:

	default:

		return SUCCESS;

	}
@@ -787,6 +787,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, 
		case SUCCESS:

		case NEEDS_RETRY:

		case FAILED:

		case TARGET_ERROR:

			break;

		case ADD_TO_MLQUEUE:

			rtn = NEEDS_RETRY;
@@ -1469,6 +1470,14 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd) 
		rtn = scsi_check_sense(scmd);

		if (rtn == NEEDS_RETRY)

			goto maybe_retry;

		else if (rtn == TARGET_ERROR) {

			/*

			 * Need to modify host byte to signal a

			 * permanent target failure

			 */

			scmd->result |= (DID_TARGET_FAILURE << 16);

			rtn = SUCCESS;

		}

		/* if rtn == FAILED, we have no sense information;

		 * returning FAILED will wake the error handler thread

		 * to collect the sense and redo the decide
@@ -1486,6 +1495,7 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd) 
	case RESERVATION_CONFLICT:

		sdev_printk(KERN_INFO, scmd->device,

			    "reservation conflict\n");

		scmd->result |= (DID_NEXUS_FAILURE << 16);

		return SUCCESS; /* causes immediate i/o error */

	default:

		return FAILED;

drivers/scsi/scsi_lib.c

+26 −2
Original line number Diff line number Diff line
@@ -667,6 +667,30 @@ void scsi_release_buffers(struct scsi_cmnd *cmd) 
}

EXPORT_SYMBOL(scsi_release_buffers);



static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)

{

	int error = 0;



	switch(host_byte(result)) {

	case DID_TRANSPORT_FAILFAST:

		error = -ENOLINK;

		break;

	case DID_TARGET_FAILURE:

		cmd->result |= (DID_OK << 16);

		error = -EREMOTEIO;

		break;

	case DID_NEXUS_FAILURE:

		cmd->result |= (DID_OK << 16);

		error = -EBADE;

		break;

	default:

		error = -EIO;

		break;

	}



	return error;

}



/*

 * Function:    scsi_io_completion()

 *
@@ -737,7 +761,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 
				req->sense_len = len;

			}

			if (!sense_deferred)

				error = -EIO;

				error = __scsi_error_from_host_byte(cmd, result);

		}



		req->resid_len = scsi_get_resid(cmd);
@@ -796,7 +820,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 
	if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)

		return;



	error = -EIO;

	error = __scsi_error_from_host_byte(cmd, result);



	if (host_byte(result) == DID_RESET) {

		/* Third party bus reset or reset for error recovery

include/scsi/scsi.h

+5 −0
Original line number Diff line number Diff line
@@ -434,6 +434,10 @@ static inline int scsi_is_wlun(unsigned int lun) 
				      * recover the link. Transport class will

				      * retry or fail IO */

#define DID_TRANSPORT_FAILFAST	0x0f /* Transport class fastfailed the io */

#define DID_TARGET_FAILURE 0x10 /* Permanent target failure, do not retry on

				 * other paths */

#define DID_NEXUS_FAILURE 0x11  /* Permanent nexus failure, retry on other

				 * paths might yield different results */

#define DRIVER_OK       0x00	/* Driver status                           */



/*
@@ -463,6 +467,7 @@ static inline int scsi_is_wlun(unsigned int lun) 
#define TIMEOUT_ERROR   0x2007

#define SCSI_RETURN_NOT_HANDLED   0x2008

#define FAST_IO_FAIL	0x2009

#define TARGET_ERROR    0x200A



/*

 * Midlevel queue return values.

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