Commit 63583cca authored by Hannes Reinecke's avatar Hannes Reinecke Committed by James Bottomley

[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
......@@ -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;
......
......@@ -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
......
......@@ -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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