[Xen-devel] [PATCH] fix restore: xenstore entries left when restore failed

[Chunyan Liu <cyliu@xxxxxxxx>]

While running libvirt-tck domain/102-broken-save-restore.t
test (save domain, corrupt saved file by truncate the last 512k,
then restore), found that restore domain failed, but domain
related xenstore entries still exist in xenstore.

Add a patch to clear xenstore entries in this case.

Signed-off-by: Chunyan Liu <cyliu@xxxxxxxx>
---
 tools/libxl/libxl.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index de23fec..447840d 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -1525,6 +1525,54 @@ static void devices_destroy_cb(libxl__egc *egc,
                                libxl__devices_remove_state *drs,
                                int rc);
 
+static void libxl_clear_xs_entry(libxl__gc *gc, uint32_t domid)
+{
+    const char *dom_path, *vm_path;
+    char *path;
+    unsigned int num_kinds, num_dev_xsentries;
+    char **kinds = NULL, **devs = NULL;
+    int i, j;
+
+    /* remove libxl path */
+    libxl__xs_rm_checked(gc, XBT_NULL, libxl__xs_libxl_path(gc, domid));
+
+    dom_path = libxl__xs_get_dompath(gc, domid);
+    if (!dom_path)
+        return;
+
+    /* remove backend entries */
+    path = GCSPRINTF("%s/device", dom_path);
+    kinds = libxl__xs_directory(gc, XBT_NULL, path, &num_kinds);
+    if (kinds && num_kinds) {
+        for (i = 0; i < num_kinds; i++) {
+            path = GCSPRINTF("%s/device/%s", dom_path, kinds[i]);
+            devs = libxl__xs_directory(gc, XBT_NULL, path, &num_dev_xsentries);
+            if (!devs)
+                continue;
+            for (j = 0; j < num_dev_xsentries; j++) {
+                path = GCSPRINTF("%s/device/%s/%s/backend",
+                                 dom_path, kinds[i], devs[j]);
+                path = libxl__xs_read(gc, XBT_NULL, path);
+                if (path)
+                    libxl__xs_rm_checked(gc, XBT_NULL, path);
+            }
+        }
+    }
+
+    path = GCSPRINTF("%s/console/backend", dom_path);
+    path = libxl__xs_read(gc, XBT_NULL, path);
+    if (path)
+        libxl__xs_rm_checked(gc, XBT_NULL, path);
+
+    /* remove vm path */
+    vm_path = libxl__xs_read(gc, XBT_NULL, GCSPRINTF("%s/vm", dom_path));
+    if (vm_path)
+        libxl__xs_rm_checked(gc, XBT_NULL, vm_path);
+
+    /* remove dom path */
+    libxl__xs_rm_checked(gc, XBT_NULL, dom_path);
+}
+
 void libxl__destroy_domid(libxl__egc *egc, libxl__destroy_domid_state *dis)
 {
     STATE_AO_GC(dis->ao);
@@ -1540,6 +1588,10 @@ void libxl__destroy_domid(libxl__egc *egc, 
libxl__destroy_domid_state *dis)
         break;
     case ERROR_INVAL:
         LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "non-existant domain %d", domid);
+        /* domain may not started successfully but some xenstore entries
+         * might be created already in earlier stage. We need to clear
+         * those entries. */
+        libxl_clear_xs_entry(gc, domid);
     default:
         goto out;
     }
-- 
1.8.4.5


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