[SCSI] libosd: Error handling revamped

Administer some love to the osd_req_decode_sense function

* Fix a bad bug with osd_req_decode_sense(). If there was no scsi
  residual, .i.e the request never reached the target, then all the
  osd_sense_info members where garbage.

* Add grossly missing in/out_resid to osd_sense_info and fill them in
  properly.

* Define an osd_err_priority enum which divides the possible errors into
  7 categories in ascending severity. Each category is also assigned a
  Linux return code translation.

  Analyze the different osd/scsi/block returned errors and set the
  proper osd_err_priority and Linux return code accordingly.

* extra check a few situations so not to get stuck with inconsistent
  error view. Example an empty residual with an error code, and other
  places ...

Lots of libosd's osd_req_decode_sense clients had this logic in some
form or another. Consolidate all these into one place that should
actually know about osd returns. Thous translating it to a more
abstract error.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 25 insertions, 1 deletions

diff --git a/include/scsi/osd_initiator.h b/include/scsi/osd_initiator.h
index 3ec346e15dda..39d6d1097153 100644
--- a/include/scsi/osd_initiator.h
+++ b/include/scsi/osd_initiator.h
@@ -267,7 +267,7 @@ int osd_execute_request_async(struct osd_request *or,
  * @bad_attr_list - List of failing attributes (optional)
  * @max_attr      - Size of @bad_attr_list.
  *
- * After execution, sense + return code can be analyzed using this function. The
+ * After execution, osd_request results are analyzed using this function. The
  * return code is the final disposition on the error. So it is possible that a
  * CHECK_CONDITION was returned from target but this will return NO_ERROR, for
  * example on recovered errors. All parameters are optional if caller does
@@ -276,7 +276,31 @@ int osd_execute_request_async(struct osd_request *or,
  * of the SCSI_OSD_DPRINT_SENSE Kconfig value. Set @silent if you know the
  * command would routinely fail, to not spam the dmsg file.
  */
+
+/**
+ * osd_err_priority - osd categorized return codes in ascending severity.
+ *
+ * The categories are borrowed from the pnfs_osd_errno enum.
+ * See comments for translated Linux codes returned by osd_req_decode_sense.
+ */
+enum osd_err_priority {
+	OSD_ERR_PRI_NO_ERROR	= 0,
+	/* Recoverable, caller should clear_highpage() all pages */
+	OSD_ERR_PRI_CLEAR_PAGES = 1, /* -EFAULT */
+	OSD_ERR_PRI_RESOURCE	= 2, /* -ENOMEM */
+	OSD_ERR_PRI_BAD_CRED	= 3, /* -EINVAL */
+	OSD_ERR_PRI_NO_ACCESS	= 4, /* -EACCES */
+	OSD_ERR_PRI_UNREACHABLE	= 5, /* any other */
+	OSD_ERR_PRI_NOT_FOUND	= 6, /* -ENOENT */
+	OSD_ERR_PRI_NO_SPACE	= 7, /* -ENOSPC */
+	OSD_ERR_PRI_EIO		= 8, /* -EIO    */
+};
+
 struct osd_sense_info {
+	u64 out_resid;		/* Zero on success otherwise out residual */
+	u64 in_resid;		/* Zero on success otherwise in residual */
+	enum osd_err_priority osd_err_pri;
+
 	int key;		/* one of enum scsi_sense_keys */
 	int additional_code ;	/* enum osd_additional_sense_codes */
 	union { /* Sense specific information */