[dm-devel] [RHEL 5.3 PATCH 1/1] scsi_dh: add ALUA notification for EMC Clariion devices.

[Levy_Jerome at emc.com]

Adding sense code data decode for optimal/non-optimal path changeover.
Unfortunately in the read sense code we can't do another inquiry, so we
can't tell the user whether we are on the optimal or non-optimal path,
only that a change has occurred. 

Jerry Levy, Engineer IV
EMC Global Services Technical Support, PREM ISG
AMER Host Systems Software - UNIX
---

--- scsi_dh_emc.original.c      2008-09-17 14:50:18.000000000 -0400
+++ scsi_dh_emc.c       2008-09-17 14:54:38.000000000 -0400
@@ -435,6 +435,16 @@
                        return SUCCESS;
                break;
        case UNIT_ATTENTION:
+                if (sense_hdr->asc == 0x2A && sense_hdr->ascq == 0x06)
+                        /*
+                         * ALUA status has changed. Report to host,
+                         * no further action required... jml
+                         */
+                        sdev_printk(KERN_NOTICE, sdev,
+                                    "%s: Asymetric access state has
changed.\n",
+                                    CLARIION_NAME);
+                        return SUCCESS;
+                break;
                if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
                        /*
                         * Unit Attention Code. This is the first IO