storage: Validate the device formats at logical startup

At startup time, rather than blindly trusting the target devices are
still properly formatted, let's check to make sure the pool's target
devices are all properly formatted before attempting to start the pool.

Signed-off-by: John Ferlan <jferlan@redhat.com>

src/storage/storage_backend_logical.c

@@ -743,6 +743,19 @@ static int
 virStorageBackendLogicalStartPool(virConnectPtr conn ATTRIBUTE_UNUSED,
                                   virStoragePoolObjPtr pool)
 {
+    size_t i;
+
+    /* Let's make sure the pool's devices are properly formatted */
+    for (i = 0; i < pool->def->source.ndevice; i++) {
+        const char *path = pool->def->source.devices[i].path;
+
+        /* The blkid FS and Part probing code doesn't know "lvm2" (this
+         * pool's only format type), but it does know "LVM2_member", so
+         * we'll pass that here */
+        if (!virStorageBackendDeviceIsEmpty(path, "LVM2_member", false))
+            return -1;
+    }
+
     /* Let's make sure that the pool's name matches the pvs output and
      * that the pool's source devices match the pvs output.
      */