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[SCSI] Add detailed SCSI I/O errors

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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: Hannes Reinecke <hare@suse.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
This commit is contained in:
Hannes Reinecke
2011-01-18 10:13:11 +01:00
committed by James Bottomley
parent 7a1e9d829f
commit 63583cca74
3 changed files with 48 additions and 9 deletions
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28
drivers/scsi/scsi_lib.c
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@ -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