[libvirt] [PATCH] qemu_migration: Don't error on tunelled migration with --copy-storage

[Michal Privoznik]

https://bugzilla.redhat.com/show_bug.cgi?id=979477

Since 1.0.3 we are using the new way to copy non shared storage during
migration (the NBD way). However, whether the new or old way is used is
not controllable by user but unconditionally turned on if both sides of
migration support it. Moreover, the implementation is not complete: the
combination for VIR_MIGRATE_TUNNELLED flag is missing (as we need to
open new port on the destination) in which case we just error out. This
is deadly combination: not letting users choose their destiny and
erroring out. We should not do that but VIR_WARN and turn the NBD off
instead.
---

Probably worth backporting to v1.0.3+ maint branches too.

 src/qemu/qemu_migration.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 3dedfe8..b905459 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -1994,16 +1994,15 @@ static char
 
     if (flags & (VIR_MIGRATE_NON_SHARED_DISK | VIR_MIGRATE_NON_SHARED_INC) &&
         virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_NBD_SERVER)) {
         /* TODO support NBD for TUNNELLED migration */
         if (flags & VIR_MIGRATE_TUNNELLED) {
-            virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
-                _("NBD in tunnelled migration is currently not supported"));
-            goto cleanup;
+            VIR_WARN("NBD in tunnelled migration is currently not supported");
+        } else {
+            cookieFlags |= QEMU_MIGRATION_COOKIE_NBD;
+            priv->nbdPort = 0;
         }
-        cookieFlags |= QEMU_MIGRATION_COOKIE_NBD;
-        priv->nbdPort = 0;
     }
 
     if (!(mig = qemuMigrationEatCookie(driver, vm, NULL, 0, 0)))
         goto cleanup;
 
-- 
1.8.1.5