Redefine pool after pool creation failure,give out err msg for non-exsisted vg when starting pool.
ref:
http://www.redhat.com/archives/libvir-list/2011-November/msg01152.html
http://www.redhat.com/archives/libvir-list/2011-November/msg01152.html

src/storage/storage_backend_logical.c:just give out err msg for non-exsisted vg,not combine pool-build in pool-create ,since undo build for kinds of pool(iscsi,multipath) when err occours cause a lot of trouble.

src/storage/storage_driver.c:add redefinition of pool,pool may change in pool-start,redefine it after free the pool

Signed-off-by: Wen Ruo Lv <lvroyce@linux.vnet.ibm.com>
---
 src/storage/storage_backend_logical.c |   10 ++++++++++
 src/storage/storage_driver.c          |   29 +++++++++++++++++++++++++----
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/src/storage/storage_backend_logical.c b/src/storage/storage_backend_logical.c
index 3c3e736..994c792 100644
--- a/src/storage/storage_backend_logical.c
+++ b/src/storage/storage_backend_logical.c
@@ -50,6 +50,16 @@ virStorageBackendLogicalSetActive(virStoragePoolObjPtr pool,
 {
     const char *cmdargv[4];
 
+    cmdargv[0] = VGS;
+    cmdargv[1] = pool->def->source.name;
+    cmdargv[2] = NULL;

+
+    if (virRun(cmdargv, NULL) < 0) {
+        virStorageReportError(VIR_ERR_INTERNAL_ERROR,
+                                  _("vg '%s' does not exsist,try pool-build"), pool->def->source.name);
+        return -1;
+    }

+
     cmdargv[0] = VGCHANGE;
     cmdargv[1] = on ? "-ay" : "-an";
     cmdargv[2] = pool->def->source.name;
diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
index 8c2d6e1..a5cbafe 100644
--- a/src/storage/storage_driver.c
+++ b/src/storage/storage_driver.c
@@ -526,6 +526,7 @@ storagePoolCreate(virConnectPtr conn,
     virStoragePoolObjPtr pool = NULL;
     virStoragePoolPtr ret = NULL;
     virStorageBackendPtr backend;
+    int duppool;
 
     virCheckFlags(0, NULL);
 
@@ -533,7 +534,7 @@ storagePoolCreate(virConnectPtr conn,
     if (!(def = virStoragePoolDefParseString(xml)))
         goto cleanup;
 
-    if (virStoragePoolObjIsDuplicate(&driver->pools, def, 1) < 0)
+    if ((duppool = virStoragePoolObjIsDuplicate(&driver->pools, def, 1)) < 0)
         goto cleanup;
 
     if (virStoragePoolSourceFindDuplicate(&driver->pools, def) < 0)
@@ -544,26 +545,46 @@ storagePoolCreate(virConnectPtr conn,
 
     if (!(pool = virStoragePoolObjAssignDef(&driver->pools, def)))
         goto cleanup;
-    def = NULL;
 
     if (backend->startPool &&
         backend->startPool(conn, pool) < 0) {
         virStoragePoolObjRemove(&driver->pools, pool);
-        pool = NULL;
+
+        if (duppool) {
+            if (!(def = virStoragePoolDefParseString(xml)))
+                goto cleanup;
+
+            pool = virStoragePoolObjAssignDef(&driver->pools, def);
+        }
+        else
+            pool = NULL;

+
+        def = NULL;
         goto cleanup;
     }
 
     if (backend->refreshPool(conn, pool) < 0) {
         if (backend->stopPool)
             backend->stopPool(conn, pool);
+
         virStoragePoolObjRemove(&driver->pools, pool);
-        pool = NULL;
+
+        if (duppool) {
+            if (!(def = virStoragePoolDefParseString(xml)))
+                goto cleanup;
+            pool = virStoragePoolObjAssignDef(&driver->pools, def);
+        }
+        else
+            pool = NULL;
+
+        def = NULL;