[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: Hannes Reinecke <hare@suse.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9045c52..8d4ef8e 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -667,6 +667,30 @@
}
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 @@
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 @@
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