[libvirt] RE: [RFC] Multi-IQN proposal

[Matt_Domsch at Dell.com]

Do you also need to specify the expected mapping of initiator IQN to use
for each target IQN, or is that not necessary?

--
Matt Domsch
Technology Strategist, Dell Office of the CTO
linux.dell.com & www.dell.com/linux


-----Original Message-----
From: Iyer, Shyam 
Sent: Friday, September 25, 2009 2:15 PM
To: libvir-list at redhat.com
Cc: Domsch, Matt; Bellad, Sudhir; KM, Paniraja
Subject: [RFC] Multi-IQN proposal

Would this proposal be acceptable ?

Example XML schema for an iSCSI storage pool created --

 <pool type="iscsi">
  <name>dell</name>
  <uuid>cf354733-b01b-8870-2040-94888640e24d</uuid>
  <capacity>0</capacity>
  <allocation>0</allocation>
  <available>0</available>
- <source>
  <initiator iqnname = "<initiator IQN1>">
  <initiator iqnname = "<initiator IQN2>">
  ........................................
  ........................................
  <host name="<iSCSI target hostname or Target IP address>" />
  <device path="<iSCSI Target IQN name>" />
  </source>
- <target>
  <path>/dev/disk/by-path</path>
- <permissions>
  <mode>0700</mode>
  <owner>0</owner>
  <group>0</group>
  </permissions>
  </target>
  </pool>

Each initiator iqn name can be parsed to create the unique sessions.

This should solve the following possibilities --

* possibility of multiple IQNs for a single Guest
* option for Guest's own BIOS & initiator to use these IQNs (iSCSI in
Guest)
* option for hypervisor's initiator to use these IQNs on behalf of the
guest
(Multi-IQN)


Compile tested only. Needs beatification.

diff --git a/src/storage_conf.c b/src/storage_conf.c
index cb063cc..915e897 100644
--- a/src/storage_conf.c
+++ b/src/storage_conf.c
@@ -116,6 +116,7 @@ enum {
     VIR_STORAGE_POOL_SOURCE_DIR     = (1<<2),
     VIR_STORAGE_POOL_SOURCE_ADAPTER = (1<<3),
     VIR_STORAGE_POOL_SOURCE_NAME    = (1<<4),
+    VIR_STORAGE_POOL_SOURCE_INITIATOR_IQN  = (1<<5),
 };


@@ -537,6 +538,33 @@ virStoragePoolDefParseXML(virConnectPtr conn,
             goto cleanup;
         }
     }
+
+/* Read the conf here */
+    if (options->flags & VIR_STORAGE_POOL_SOURCE_INITATOR_IQN) {
+       int niqn, i;
+
+       if ((niqn = virXPathNodeSet(conn, "./source/host/initiator",
ctxt, &nodeset)) < 0) {
+            virStorageReportError(conn, VIR_ERR_XML_ERROR,
+                        "%s", _("cannot extract storage pool source
devices"));
+            goto cleanup;
+        }
+       if (VIR_ALLOC_N(ret->source.niqn, niqn) < 0) {
+            VIR_FREE(nodeset);
+            virReportOOMError(conn);
+            goto cleanup;
+        }
+       for (i = 0 ; i < niqn ; i++ ) {
+           xmlChar *name = xmlGetProp(nodeset[i], BAD_CAST "iqnname");
+            if (path == NULL) {
+                VIR_FREE(nodeset);
+                virStorageReportError(conn, VIR_ERR_XML_ERROR,
+                        "%s", _("missing storage pool source device
path"));
+                goto cleanup;
+            }
+           ret->source.initiator[i].iqnname  = (char  *)name;
+       }
+    }
     if (options->flags & VIR_STORAGE_POOL_SOURCE_DEVICE) {
         xmlNodePtr *nodeset = NULL;
         int nsource, i;
diff --git a/src/storage_conf.h b/src/storage_conf.h
index 421d305..c2504be 100644
--- a/src/storage_conf.h
+++ b/src/storage_conf.h
@@ -202,7 +202,12 @@ struct _virStoragePoolSourceDevice {
     } geometry;
 };

-
+/* Initiator Attributes */
+typedef virStoragePoolSourceInitiatorAttr
*virStoragePoolSourceInitiatorAttrPtr;
+struct virStoragePoolSourceInitiatorAttr {
+    char *iqnname;
+    /* We could put other initiator specific things here */
+}

 typedef struct _virStoragePoolSource virStoragePoolSource;
 typedef virStoragePoolSource *virStoragePoolSourcePtr;
@@ -214,6 +219,9 @@ struct _virStoragePoolSource {
     int ndevice;
     virStoragePoolSourceDevicePtr devices;

+    /*And either one or more initiators*/
+    virStoragePoolSourceInitiatorAttrPtr initiator;
+
     /* Or a directory */
     char *dir;