From a1c9a81a318f3cd558faed7fc4c4933f95c07a07 Mon Sep 17 00:00:00 2001
From: Jim Fehlig <jfehlig@suse.com>
Date: Mon, 23 May 2016 15:56:01 -0600
Subject: [PATCH] libxl: default to qemu driver for network disks

Xen only supports network-based disks with the qemu (aka qdisk) driver.
Set the driverName to 'qemu' in libxlDomainDeviceDefPostParse() if
not already set. When starting a domain with network-based disks,
ensure the driverName is 'qemu'.

Resolves: https://bugzilla.opensuse.org/show_bug.cgi?id=981094
---
 src/libxl/libxl_conf.c   | 11 +++++++----
 src/libxl/libxl_domain.c | 12 ++++++++++++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index 13e56ac1ff..a64b4c17d8 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -1058,13 +1058,18 @@ libxlMakeNetworkDiskSrc(virStorageSourcePtr src, char **srcstr)
 int
 libxlMakeDisk(virDomainDiskDefPtr l_disk, libxl_device_disk *x_disk)
 {
-    const char *driver;
-    int format;
+    const char *driver = virDomainDiskGetDriver(l_disk);
+    int format = virDomainDiskGetFormat(l_disk);
     int actual_type = virStorageSourceGetActualType(l_disk->src);
 
     libxl_device_disk_init(x_disk);
 
     if (actual_type == VIR_STORAGE_TYPE_NETWORK) {
+        if (STRNEQ_NULLABLE(driver, "qemu")) {
+            virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                           _("only the 'qemu' driver can be used with network disks"));
+            return -1;
+        }
         if (libxlMakeNetworkDiskSrc(l_disk->src, &x_disk->pdev_path) < 0)
             return -1;
     } else {
@@ -1075,8 +1080,6 @@ libxlMakeDisk(virDomainDiskDefPtr l_disk, libxl_device_disk *x_disk)
     if (VIR_STRDUP(x_disk->vdev, l_disk->dst) < 0)
         return -1;
 
-    driver = virDomainDiskGetDriver(l_disk);
-    format = virDomainDiskGetFormat(l_disk);
     if (driver) {
         if (STREQ(driver, "tap") || STREQ(driver, "tap2")) {
             switch (format) {
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
index 113942bb8e..8a3866f90f 100644
--- a/src/libxl/libxl_domain.c
+++ b/src/libxl/libxl_domain.c
@@ -364,6 +364,18 @@ libxlDomainDeviceDefPostParse(virDomainDeviceDefPtr dev,
         }
     }
 
+    /* for network-based disks, set 'qemu' as the default driver */
+    if (dev->type == VIR_DOMAIN_DEVICE_DISK) {
+        virDomainDiskDefPtr disk = dev->data.disk;
+        int actual_type = virStorageSourceGetActualType(disk->src);
+
+        if (actual_type == VIR_STORAGE_TYPE_NETWORK) {
+            if (!virDomainDiskGetDriver(disk) &&
+                virDomainDiskSetDriver(disk, "qemu") < 0)
+                return -1;
+        }
+    }
+
     return 0;
 }