Revert "storage: lvm: Separate creating of the volume from building"

This reverts commit af1fb38f.
With it, creating new logical volumes fails:
https://www.redhat.com/archives/libvir-list/2014-February/msg00658.html

In the storage driver, we expect CreateVol to fill out the volume key,
but the LVM backend fills the key with the uuid reported by lvs after the
logical volume is created.

src/storage/storage_backend_logical.c

@@ -702,16 +702,32 @@ cleanup:
 
 
 static int
-virStorageBackendLogicalBuildVol(virConnectPtr conn,
-                                 virStoragePoolObjPtr pool,
-                                 virStorageVolDefPtr vol,
-                                 unsigned int flags)
+virStorageBackendLogicalCreateVol(virConnectPtr conn,
+                                  virStoragePoolObjPtr pool,
+                                  virStorageVolDefPtr vol)
 {
     int fd = -1;
     virCommandPtr cmd = NULL;
     virErrorPtr err;
 
-    virCheckFlags(0, -1);
+    if (vol->target.encryption != NULL) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       "%s", _("storage pool does not support encrypted "
+                               "volumes"));
+        return -1;
+    }
+
+    vol->type = VIR_STORAGE_VOL_BLOCK;
+
+    if (vol->target.path != NULL) {
+        /* A target path passed to CreateVol has no meaning */
+        VIR_FREE(vol->target.path);
+    }
+
+    if (virAsprintf(&vol->target.path, "%s/%s",
+                    pool->def->target.path,
+                    vol->name) == -1)
+        return -1;
 
     cmd = virCommandNewArgList(LVCREATE,
                                "--name", vol->name,
@@ -770,7 +786,7 @@ virStorageBackendLogicalBuildVol(virConnectPtr conn,
 
     return 0;
 
-error:
+ error:
     err = virSaveLastError();
     VIR_FORCE_CLOSE(fd);
     virStorageBackendLogicalDeleteVol(conn, pool, vol, 0);
@@ -780,36 +796,6 @@ error:
     return -1;
 }
 
-
-static int
-virStorageBackendLogicalCreateVol(virConnectPtr conn ATTRIBUTE_UNUSED,
-                                  virStoragePoolObjPtr pool,
-                                  virStorageVolDefPtr vol)
-{
-    if (vol->target.encryption != NULL) {
-        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
-                       _("storage pool does not support encrypted volumes"));
-        return -1;
-    }
-
-    vol->type = VIR_STORAGE_VOL_BLOCK;
-
-    VIR_FREE(vol->target.path);
-    if (virAsprintf(&vol->target.path, "%s/%s",
-                    pool->def->target.path,
-                    vol->name) == -1)
-        return -1;
-
-    if (virFileExists(vol->target.path)) {
-        virReportError(VIR_ERR_OPERATION_INVALID,
-                       _("volume target path '%s' already exists"),
-                       vol->target.path);
-        return -1;
-    }
-
-    return 0;
-}
-
 static int
 virStorageBackendLogicalBuildVolFrom(virConnectPtr conn,
                                      virStoragePoolObjPtr pool,
@@ -837,7 +823,7 @@ virStorageBackend virStorageBackendLogical = {
     .refreshPool = virStorageBackendLogicalRefreshPool,
     .stopPool = virStorageBackendLogicalStopPool,
     .deletePool = virStorageBackendLogicalDeletePool,
-    .buildVol = virStorageBackendLogicalBuildVol,
+    .buildVol = NULL,
     .buildVolFrom = virStorageBackendLogicalBuildVolFrom,
     .createVol = virStorageBackendLogicalCreateVol,
     .deleteVol = virStorageBackendLogicalDeleteVol,