[PATCH 27/35] qemuDomainAttachDiskGeneric: Refactor rollback handling

[Peter Krempa]

Modify the rollback section to use it's own monitor context so that we
can later split up the hotplug into multiple steps and move the
detachment of the extension device into the rollback section rather than
doing it inline.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 src/qemu/qemu_hotplug.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index f8c741c683..3772c5b4b8 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -699,6 +699,8 @@ qemuDomainAttachDiskGeneric(virQEMUDriver *driver,
     qemuDomainObjPrivate *priv = vm->privateData;
     g_autofree char *devstr = NULL;
     bool blockdev = virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV);
+    bool extensionDeviceAttached = false;
+    int rc;

     if (virStorageSourceGetActualType(disk->src) == VIR_STORAGE_TYPE_VHOST_USER) {
         if (!(data = qemuBuildStorageSourceChainAttachPrepareChardev(disk)))
@@ -726,16 +728,14 @@ qemuDomainAttachDiskGeneric(virQEMUDriver *driver,

     qemuDomainObjEnterMonitor(driver, vm);

-    if (qemuBlockStorageSourceChainAttach(priv->mon, data) < 0)
-        goto exit_monitor;
+    rc = qemuBlockStorageSourceChainAttach(priv->mon, data);

-    if (qemuDomainAttachExtensionDevice(priv->mon, &disk->info) < 0)
-        goto exit_monitor;
+    if (rc == 0 &&
+        (rc = qemuDomainAttachExtensionDevice(priv->mon, &disk->info)) == 0)
+        extensionDeviceAttached = true;

-    if (qemuMonitorAddDevice(priv->mon, devstr) < 0) {
-        ignore_value(qemuDomainDetachExtensionDevice(priv->mon, &disk->info));
-        goto exit_monitor;
-    }
+    if (rc == 0)
+        rc = qemuMonitorAddDevice(priv->mon, devstr);

     /* Setup throttling of disk via block_set_io_throttle QMP command. This
      * is a hack until the 'throttle' blockdev driver will support modification
@@ -743,7 +743,7 @@ qemuDomainAttachDiskGeneric(virQEMUDriver *driver,
      * As there isn't anything sane to do if this fails, let's just return
      * success.
      */
-    if (blockdev &&
+    if (blockdev && rc == 0 &&
         qemuDiskConfigBlkdeviotuneEnabled(disk)) {
         qemuDomainDiskPrivate *diskPriv = QEMU_DOMAIN_DISK_PRIVATE(disk);
         if (qemuMonitorSetBlockIoThrottle(priv->mon, NULL, diskPriv->qomName,
@@ -755,9 +755,17 @@ qemuDomainAttachDiskGeneric(virQEMUDriver *driver,
     if (qemuDomainObjExitMonitor(driver, vm) < 0)
         return -2;

+    if (rc < 0)
+        goto rollback;
+
     return 0;

- exit_monitor:
+ rollback:
+    qemuDomainObjEnterMonitor(driver, vm);
+
+    if (extensionDeviceAttached)
+        ignore_value(qemuDomainDetachExtensionDevice(priv->mon, &disk->info));
+
     qemuBlockStorageSourceChainDetach(priv->mon, data);

     if (qemuDomainObjExitMonitor(driver, vm) < 0)
-- 
2.31.1