libxl: fix leaking of allocated migration ports

Although the migration port is immediately released in the
finish phase of migration, it was never set in the domain
private object when allocated in the prepare phase. So
libxlDomainMigrationFinish() always released a 0-initialized
migrationPort, leaking any allocated port. After enough
migrations to exhaust the migration port pool, migration would
fail with

error: internal error: Unable to find an unused port in range
       'migration' (49152-49216)

Fix it by setting libxlDomainObjPrivate->migrationPort to the
port allocated in the prepare phase. While at it, also fix
leaking an allocated port if the prepare phase fails.

diff --git a/src/libxl/libxl_migration.c b/src/libxl/libxl_migration.c
index 534abb8704bb7b9a8d21f7d51865fae70055f2b3..a471d2aa1154e5b451498ba5afaddebec1a95ee8 100644 (file)
--- a/src/libxl/libxl_migration.c
+++ b/src/libxl/libxl_migration.c
@@ -594,6 +594,7 @@ libxlDomainMigrationPrepare(virConnectPtr dconn,
         if (virPortAllocatorAcquire(driver->migrationPorts, &port) < 0)
             goto error;
 
+        priv->migrationPort = port;
         if (virAsprintf(uri_out, "tcp://%s:%d", hostname, port) < 0)
             goto error;
     } else {
@@ -628,6 +629,7 @@ libxlDomainMigrationPrepare(virConnectPtr dconn,
             if (virPortAllocatorAcquire(driver->migrationPorts, &port) < 0)
                 goto error;
 
+            priv->migrationPort = port;
         } else {
             port = uri->port;
         }
@@ -690,6 +692,8 @@ libxlDomainMigrationPrepare(virConnectPtr dconn,
     }
     VIR_FREE(socks);
     virObjectUnref(args);
+    virPortAllocatorRelease(driver->migrationPorts, priv->migrationPort);
+    priv->migrationPort = 0;
 
     /* Remove virDomainObj from domain list */
     if (vm) {