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[libvirt] iSCSI Multi-IQN (Libvirt Support)



The following patch set realizes the multi-IQN concept discussed in an
earlier thread
http://www.mail-archive.com/libvir-list redhat com/msg16706.html

The patch realizes an XML schema like the one below and allows libvirt
to read through it to create storage pools. 
These XMLs when created using a virtualization manager realize unique VM
to storage LUN mappings through a single console and thus opening up
possibilities for the following scenarios -

* possibility of multiple IQNs for a single Guest
* option for hypervisor's initiator to use these IQNs on behalf of the
guest

Example Usages:
Usage 1:
VM1 - > <Init iqn1> <------------------------> <Target iqn1>
        <Init iqn2> <------------------------> <Target iqn1>
        <Init iqn3> <------------------------> <Target iqn1>
        <Init iqn4> <------------------------> <Target iqn1>

Usage 2:
VM1 - > <Init iqn1> <------------------------> <Target iqn1>
        <Init iqn2> <------------------------> <Target iqn2>
        <Init iqn3> <------------------------> <Target iqn3>
        <Init iqn4> <------------------------> <Target iqn4>

Usage 3:
VM1 - > <Init iqn1> <------------------------> <Target iqn1>

VM2 - > <Init iqn2> <------------------------> <Target iqn1>

Usage 4:
VM1 - > <Init iqn1> <------------------------> <Target iqn1>

VM2 - > <Init iqn2> <------------------------> <Target iqn2>

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>">
  iqnname = "<initiator IQN2>">
  </initiator>
  ........................................
  ........................................
  <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.

TODO:
1) Virt Manager GUI support to allow a visual mapping of iqn->storage
pool -> VM and thus creating the XML for consumption by libvirt.
Libvirt support added above can realize the same using virsh options.

2) option for Guest's own BIOS & initiator to use the initiator IQNs
(iSCSI in Guest)
	a) Libvirt support to allow iqn as an attribute for a VM's XML.
	b) Qemu Support to allow Guest's bios & initiator to use these
IQNs.


Signed-off-by: Sudhir Bellad <sudhir_bellad dell com>
Signed-off-by: Shyam Iyer <shyam_iyer dell com>

diff --git a/src/storage_backend_iscsi.c b/src/storage_backend_iscsi.c
index b516add..3f2a79d 100644
--- a/src/storage_backend_iscsi.c
+++ b/src/storage_backend_iscsi.c
@@ -39,6 +39,10 @@
 #include "storage_backend_iscsi.h"
 #include "util.h"
 #include "memory.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>

 #define VIR_FROM_THIS VIR_FROM_STORAGE

@@ -159,13 +163,57 @@ virStorageBackendISCSIConnection(virConnectPtr
conn,
                                  const char *portal,
                                  const char *action)
 {
-    const char *const cmdargv[] = {
-        ISCSIADM, "--mode", "node", "--portal", portal,
-        "--targetname", pool->def->source.devices[0].path, action, NULL
-    };
-
-    if (virRun(conn, cmdargv, NULL) < 0)
-        return -1;
+    DIR *dir;
+    struct dirent *entry;
+
+
+       if (pool->def->source.initiator[0].iqnname != NULL) {
+               int i = 0;
+               while(pool->def->source.initiator[i].iqnname != NULL){
+                       if (!(dir = opendir(IFACES_DIR))) {
+                               if (errno == ENOENT)
+                               return 0;
+                               virReportSystemError(conn, errno,
_("Failed to open dir '%s'"),
+                               IFACES_DIR);
+                               return -1;
+                       }
+                       while ((entry = readdir(dir))) {
+                               FILE *fp;
+                               char path[PATH_MAX];
+
+                               if (entry->d_name[0] == '.')
+                                       continue;
+
+                               sprintf(path,"%s", IFACES_DIR);
+                               strcat(path,(const char
*)entry->d_name);
+
+                                       if ((fp = fopen(path, "r"))){
+                                       char buff[256];
+                                       while (fp != NULL && fgets(buff,
sizeof(buff), fp) != NULL) {
+                                                       if (strstr(buff,
pool->def->source.initiator[i].iqnname) != NULL) {
+                                                       const char
*const cmdargv[] = {
+
ISCSIADM, "--mode", "node", "--portal", portal,
+
"--targetname", pool->def->source.devices[0].path, "-I", entry->d_name,
action, NULL
+                                                               };
+
+
if (virRun(conn, cmdargv, NULL) < 0)
+
return -1;
+                                                       }
+                                               }
+                                       }
+                               fclose(fp);
+                       }
+               i++;
+               }
+       }
+       else{
+               const char *const cmdargv[] = {
+               ISCSIADM, "--mode", "node", "--portal", portal,
+               "--targetname", pool->def->source.devices[0].path,
action, NULL
+               };
+               if (virRun(conn, cmdargv, NULL) < 0)
+               return -1;
+       }

     return 0;
 }
diff --git a/src/storage_backend_iscsi.h b/src/storage_backend_iscsi.h
index 665ed13..14c2c5c 100644
--- a/src/storage_backend_iscsi.h
+++ b/src/storage_backend_iscsi.h
@@ -25,7 +25,7 @@
 #define __VIR_STORAGE_BACKEND_ISCSI_H__

 #include "storage_backend.h"
-
extern virStorageBackend virStorageBackendISCSI;
+#define IFACES_DIR "/var/lib/iscsi/ifaces/"

 #endif /* __VIR_STORAGE_BACKEND_ISCSI_H__ */
diff --git a/src/storage_conf.c b/src/storage_conf.c
index 788de15..0f2ace9 100644
--- a/src/storage_conf.c
+++ b/src/storage_conf.c
@@ -106,12 +106,13 @@ struct _virStorageVolOptions {

 /* Flags to indicate mandatory components in the pool source */
 enum {
-    VIR_STORAGE_POOL_SOURCE_HOST    = (1<<0),
-    VIR_STORAGE_POOL_SOURCE_DEVICE  = (1<<1),
-    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_HOST             = (1<<0),
+    VIR_STORAGE_POOL_SOURCE_DEVICE           = (1<<1),
+    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),
+ };



@@ -179,7 +180,8 @@ static virStoragePoolTypeInfo poolTypeInfo[] = {
     { .poolType = VIR_STORAGE_POOL_ISCSI,
       .poolOptions = {
             .flags = (VIR_STORAGE_POOL_SOURCE_HOST |
-                      VIR_STORAGE_POOL_SOURCE_DEVICE),
+                      VIR_STORAGE_POOL_SOURCE_DEVICE |
+                     VIR_STORAGE_POOL_SOURCE_INITIATOR_IQN),
         },
       .volOptions = {
             .formatToString = virStoragePoolFormatDiskTypeToString,
@@ -532,6 +534,34 @@ virStoragePoolDefParseXML(virConnectPtr conn,
             goto cleanup;
         }
     }
+
+    if(options->flags & VIR_STORAGE_POOL_SOURCE_INITIATOR_IQN) {
+      xmlNodePtr *nodeset = NULL;
+      int niqn, i;
+
+      if((niqn = virXPathNodeSet(conn, "./initiator/iqnname", ctxt,
&nodeset)) < 0) {
+         virStorageReportError(conn, VIR_ERR_XML_ERROR,
+                        "%s", _("cannot extract storage pool source
devices"));
+            goto cleanup;
+        }
+        if (VIR_ALLOC_N(ret->source.initiator, niqn) < 0) {
+            VIR_FREE(nodeset);
+            virReportOOMError(conn);
+            goto cleanup;
+        }
+        for (i = 0 ; i < niqn ; i++) {
+            xmlChar *name = xmlGetProp(nodeset[i], BAD_CAST "name");
+            if (name == 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;
+       }
+        VIR_FREE(nodeset);
+      }
+
     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 9fedb12..c77d6ae 100644
--- a/src/storage_conf.h
+++ b/src/storage_conf.h
@@ -182,6 +182,13 @@ struct _virStoragePoolSourceDeviceExtent {
     int type;  /* free space type */
 };

+typedef struct _virStoragePoolSourceInitiatorAttr
virStoragePoolSourceInitiatorAttr;
+typedef virStoragePoolSourceInitiatorAttr
*virStoragePoolSourceInitiatorAttrPtr;
+struct _virStoragePoolSourceInitiatorAttr {
+    /* Initiator iqn name */
+    char *iqnname;
+};
+
 /*
  * Pools can be backed by one or more devices, and some
  * allow us to track free space on underlying devices.
@@ -223,6 +230,9 @@ struct _virStoragePoolSource {
     /* Or a name */
     char *name;

+    /* One or more initiator names */
+    virStoragePoolSourceInitiatorAttrPtr initiator;
+
     int authType;       /* virStoragePoolAuthType */
     union {
         virStoragePoolAuthChap chap;

Attachment: libvirt_changes_0.3
Description: libvirt_changes_0.3


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