[PATCH 2/2] libxl: do not automatically force detach of block devices

[Paul Durrant <paul@xxxxxxx>]

From: Paul Durrant <pdurrant@xxxxxxxxxx>

The manpage for 'xl' documents that guest co-operation is required for a (non-
forced) block-detach operation and that it may consequently fail. Currently,
however, the implementation of generic device removal means that a time-out
of a block-detach is being automatically re-tried with the force flag set
rather than failing. This patch stops such behaviour.

Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
---
Cc: Ian Jackson <iwj@xxxxxxxxxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>
Cc: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 tools/libxl/libxl_device.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index 0381c5d509..d17ca78848 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -1092,7 +1092,8 @@ static void device_backend_callback(libxl__egc *egc, 
libxl__ev_devstate *ds,
 
     if (rc == ERROR_TIMEDOUT &&
         aodev->action == LIBXL__DEVICE_ACTION_REMOVE &&
-        !aodev->force) {
+        !aodev->force &&
+        aodev->dev->kind != LIBXL__DEVICE_KIND_VBD) {
         LOGD(DEBUG, aodev->dev->domid, "Timeout reached, initiating forced 
remove");
         aodev->force = 1;
         libxl__initiate_device_generic_remove(egc, aodev);
@@ -1103,7 +1104,8 @@ static void device_backend_callback(libxl__egc *egc, 
libxl__ev_devstate *ds,
         LOGD(ERROR, aodev->dev->domid, "unable to %s device with path %s",
                     libxl__device_action_to_string(aodev->action),
                     libxl__device_backend_path(gc, aodev->dev));
-        goto out;
+        if (!aodev->force)
+            goto out;
     }
 
     device_hotplug(egc, aodev);
@@ -1319,7 +1321,8 @@ static void device_hotplug_done(libxl__egc *egc, 
libxl__ao_device *aodev)
     device_hotplug_clean(gc, aodev);
 
     /* Clean xenstore if it's a disconnection */
-    if (aodev->action == LIBXL__DEVICE_ACTION_REMOVE) {
+    if (aodev->action == LIBXL__DEVICE_ACTION_REMOVE &&
+        (aodev->force || !aodev->rc)) {
         rc = libxl__device_destroy(gc, aodev->dev);
         if (!aodev->rc)
             aodev->rc = rc;
-- 
2.20.1