storage: Add flags to allow building pool during create processing

https://bugzilla.redhat.com/show_bug.cgi?id=830056

Add flags handling to the virStoragePoolCreate and virStoragePoolCreateXML
API's which will allow the caller to provide the capability for the storage
pool create API's to also perform a pool build during creation rather than
requiring the additional buildPool step. This will allow transient pools
to be defined, built, and started.

The new flags are:

    * VIR_STORAGE_POOL_CREATE_WITH_BUILD
      Perform buildPool without any flags passed.

    * VIR_STORAGE_POOL_CREATE_WITH_BUILD_OVERWRITE
      Perform buildPool using VIR_STORAGE_POOL_BUILD_OVERWRITE flag.

    * VIR_STORAGE_POOL_CREATE_WITH_BUILD_NO_OVERWRITE
      Perform buildPool using VIR_STORAGE_POOL_BUILD_NO_OVERWRITE flag.

It is up to the backend to handle the processing of build flags. The
overwrite and no-overwrite flags are mutually exclusive.

NB:
This patch is loosely based upon code originally authored by Osier
Yang that were not reviewed and pushed, see:

https://www.redhat.com/archives/libvir-list/2012-July/msg01328.html

include/libvirt/libvirt-storage.h

@@ -57,7 +57,6 @@ typedef enum {
 # endif
 } virStoragePoolState;
 
-
 typedef enum {
     VIR_STORAGE_POOL_BUILD_NEW  = 0,   /* Regular build from scratch */
     VIR_STORAGE_POOL_BUILD_REPAIR = (1 << 0), /* Repair / reinitialize */
@@ -71,6 +70,23 @@ typedef enum {
     VIR_STORAGE_POOL_DELETE_ZEROED = 1 << 0,  /* Clear all data to zeros (slow) */
 } virStoragePoolDeleteFlags;
 
+typedef enum {
+    VIR_STORAGE_POOL_CREATE_NORMAL = 0,
+
+    /* Create the pool and perform pool build without any flags */
+    VIR_STORAGE_POOL_CREATE_WITH_BUILD = 1 << 0,
+
+    /* Create the pool and perform pool build using the
+     * VIR_STORAGE_POOL_BUILD_OVERWRITE flag. This is mutually
+     * exclusive to VIR_STORAGE_POOL_CREATE_WITH_BUILD_NO_OVERWRITE */
+    VIR_STORAGE_POOL_CREATE_WITH_BUILD_OVERWRITE = 1 << 1,
+
+    /* Create the pool and perform pool build using the
+     * VIR_STORAGE_POOL_BUILD_NO_OVERWRITE flag. This is mutually
+     * exclusive to VIR_STORAGE_POOL_CREATE_WITH_BUILD_OVERWRITE */
+    VIR_STORAGE_POOL_CREATE_WITH_BUILD_NO_OVERWRITE = 1 << 2,
+} virStoragePoolCreateFlags;
+
 typedef struct _virStoragePoolInfo virStoragePoolInfo;
 
 struct _virStoragePoolInfo {

src/libvirt-storage.c

@@ -505,7 +505,7 @@ virStoragePoolLookupByVolume(virStorageVolPtr vol)
  * virStoragePoolCreateXML:
  * @conn: pointer to hypervisor connection
  * @xmlDesc: XML description for new pool
- * @flags: extra flags; not used yet, so callers should always pass 0
+ * @flags: bitwise-OR of virStoragePoolCreateFlags
  *
  * Create a new storage based on its XML description. The
  * pool is not persistent, so its definition will disappear
@@ -670,7 +670,7 @@ virStoragePoolUndefine(virStoragePoolPtr pool)
 /**
  * virStoragePoolCreate:
  * @pool: pointer to storage pool
- * @flags: extra flags; not used yet, so callers should always pass 0
+ * @flags: bitwise-OR of virStoragePoolCreateFlags
  *
  * Starts an inactive storage pool
  *

src/storage/storage_driver.c

@@ -671,8 +671,14 @@ storagePoolCreateXML(virConnectPtr conn,
     virStoragePoolPtr ret = NULL;
     virStorageBackendPtr backend;
     char *stateFile = NULL;
+    unsigned int build_flags = 0;
 
-    virCheckFlags(0, NULL);
+    virCheckFlags(VIR_STORAGE_POOL_CREATE_WITH_BUILD |
+                  VIR_STORAGE_POOL_CREATE_WITH_BUILD_OVERWRITE |
+                  VIR_STORAGE_POOL_CREATE_WITH_BUILD_NO_OVERWRITE, NULL);
+
+    VIR_EXCLUSIVE_FLAGS_RET(VIR_STORAGE_POOL_BUILD_OVERWRITE,
+                            VIR_STORAGE_POOL_BUILD_NO_OVERWRITE, NULL);
 
     storageDriverLock();
     if (!(def = virStoragePoolDefParseString(xml)))
@@ -694,6 +700,22 @@ storagePoolCreateXML(virConnectPtr conn,
         goto cleanup;
     def = NULL;
 
+    if (backend->buildPool) {
+        if (flags & VIR_STORAGE_POOL_CREATE_WITH_BUILD_OVERWRITE)
+            build_flags |= VIR_STORAGE_POOL_BUILD_OVERWRITE;
+        else if (flags & VIR_STORAGE_POOL_CREATE_WITH_BUILD_NO_OVERWRITE)
+            build_flags |= VIR_STORAGE_POOL_BUILD_NO_OVERWRITE;
+
+        if (build_flags ||
+            (flags & VIR_STORAGE_POOL_CREATE_WITH_BUILD)) {
+            if (backend->buildPool(conn, pool, build_flags) < 0) {
+                virStoragePoolObjRemove(&driver->pools, pool);
+                pool = NULL;
+                goto cleanup;
+            }
+        }
+    }
+
     if (backend->startPool &&
         backend->startPool(conn, pool) < 0) {
         virStoragePoolObjRemove(&driver->pools, pool);
@@ -845,8 +867,14 @@ storagePoolCreate(virStoragePoolPtr obj,
     virStorageBackendPtr backend;
     int ret = -1;
     char *stateFile = NULL;
+    unsigned int build_flags = 0;
 
-    virCheckFlags(0, -1);
+    virCheckFlags(VIR_STORAGE_POOL_CREATE_WITH_BUILD |
+                  VIR_STORAGE_POOL_CREATE_WITH_BUILD_OVERWRITE |
+                  VIR_STORAGE_POOL_CREATE_WITH_BUILD_NO_OVERWRITE, -1);
+
+    VIR_EXCLUSIVE_FLAGS_RET(VIR_STORAGE_POOL_BUILD_OVERWRITE,
+                            VIR_STORAGE_POOL_BUILD_NO_OVERWRITE, -1);
 
     if (!(pool = virStoragePoolObjFromStoragePool(obj)))
         return -1;
@@ -864,6 +892,22 @@ storagePoolCreate(virStoragePoolPtr obj,
         goto cleanup;
     }
 
+    if (backend->buildPool) {
+        if (flags & VIR_STORAGE_POOL_CREATE_WITH_BUILD_OVERWRITE)
+            build_flags |= VIR_STORAGE_POOL_BUILD_OVERWRITE;
+        else if (flags & VIR_STORAGE_POOL_CREATE_WITH_BUILD_NO_OVERWRITE)
+            build_flags |= VIR_STORAGE_POOL_BUILD_NO_OVERWRITE;
+
+        if (build_flags ||
+            (flags & VIR_STORAGE_POOL_CREATE_WITH_BUILD)) {
+            if (backend->buildPool(obj->conn, pool, build_flags) < 0) {
+                virStoragePoolObjRemove(&driver->pools, pool);
+                pool = NULL;
+                goto cleanup;
+            }
+        }
+    }
+
     VIR_INFO("Starting up storage pool '%s'", pool->def->name);
     if (backend->startPool &&
         backend->startPool(obj->conn, pool) < 0)