[qemu-xen stable-4.13] tests: make filemonitor test more robust to event ordering

[patchbot@xxxxxxx]

commit 54c130493c544573253f5bbdcdb705f3d79377f0
Author:     Daniel P. Berrangé <berrange@xxxxxxxxxx>
AuthorDate: Wed Aug 21 16:14:27 2019 +0100
Commit:     Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
CommitDate: Tue Nov 12 11:59:58 2019 -0600

    tests: make filemonitor test more robust to event ordering
    
    The ordering of events that are emitted during the rmdir
    test have changed with kernel >= 5.3. Semantically both
    new & old orderings are correct, so we must be able to
    cope with either.
    
    To cope with this, when we see an unexpected event, we
    push it back onto the queue and look and the subsequent
    event to see if that matches instead.
    
    Tested-by: Peter Xu <peterx@xxxxxxxxxx>
    Tested-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
    Tested-by: Cornelia Huck <cohuck@xxxxxxxxxx>
    Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx>
    Signed-off-by: Daniel P. Berrangé <berrange@xxxxxxxxxx>
    (cherry picked from commit bf9e0313c27d8e6ecd7f7de3d63e1cb25d8f6311)
    Signed-off-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
---
 tests/test-util-filemonitor.c | 43 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 34 insertions(+), 9 deletions(-)

diff --git a/tests/test-util-filemonitor.c b/tests/test-util-filemonitor.c
index 46e781c022..301cd2db61 100644
--- a/tests/test-util-filemonitor.c
+++ b/tests/test-util-filemonitor.c
@@ -45,6 +45,11 @@ typedef struct {
     const char *filedst;
     int64_t *watchid;
     int eventid;
+    /*
+     * Only valid with OP_EVENT - this event might be
+     * swapped with the next OP_EVENT
+     */
+    bool swapnext;
 } QFileMonitorTestOp;
 
 typedef struct {
@@ -98,6 +103,10 @@ qemu_file_monitor_test_handler(int64_t id,
     QFileMonitorTestData *data = opaque;
     QFileMonitorTestRecord *rec = g_new0(QFileMonitorTestRecord, 1);
 
+    if (debug) {
+        g_printerr("Queue event id %" PRIx64 " event %d file %s\n",
+                   id, event, filename);
+    }
     rec->id = id;
     rec->event = event;
     rec->filename = g_strdup(filename);
@@ -125,7 +134,8 @@ qemu_file_monitor_test_record_free(QFileMonitorTestRecord 
*rec)
  * to wait for the event to be queued for us.
  */
 static QFileMonitorTestRecord *
-qemu_file_monitor_test_next_record(QFileMonitorTestData *data)
+qemu_file_monitor_test_next_record(QFileMonitorTestData *data,
+                                   QFileMonitorTestRecord *pushback)
 {
     GTimer *timer = g_timer_new();
     QFileMonitorTestRecord *record = NULL;
@@ -139,9 +149,15 @@ qemu_file_monitor_test_next_record(QFileMonitorTestData 
*data)
     }
     if (data->records) {
         record = data->records->data;
-        tmp = data->records;
-        data->records = g_list_remove_link(data->records, tmp);
-        g_list_free(tmp);
+        if (pushback) {
+            data->records->data = pushback;
+        } else {
+            tmp = data->records;
+            data->records = g_list_remove_link(data->records, tmp);
+            g_list_free(tmp);
+        }
+    } else if (pushback) {
+        qemu_file_monitor_test_record_free(pushback);
     }
     qemu_mutex_unlock(&data->lock);
 
@@ -158,13 +174,15 @@ static bool
 qemu_file_monitor_test_expect(QFileMonitorTestData *data,
                               int64_t id,
                               QFileMonitorEvent event,
-                              const char *filename)
+                              const char *filename,
+                              bool swapnext)
 {
     QFileMonitorTestRecord *rec;
     bool ret = false;
 
-    rec = qemu_file_monitor_test_next_record(data);
+    rec = qemu_file_monitor_test_next_record(data, NULL);
 
+ retry:
     if (!rec) {
         g_printerr("Missing event watch id %" PRIx64 " event %d file %s\n",
                    id, event, filename);
@@ -172,6 +190,11 @@ qemu_file_monitor_test_expect(QFileMonitorTestData *data,
     }
 
     if (id != rec->id) {
+        if (swapnext) {
+            rec = qemu_file_monitor_test_next_record(data, rec);
+            swapnext = false;
+            goto retry;
+        }
         g_printerr("Expected watch id %" PRIx64 " but got %" PRIx64 "\n",
                    id, rec->id);
         goto cleanup;
@@ -347,7 +370,8 @@ test_file_monitor_events(void)
           .filesrc = "fish", },
         { .type = QFILE_MONITOR_TEST_OP_EVENT,
           .filesrc = "", .watchid = &watch4,
-          .eventid = QFILE_MONITOR_EVENT_IGNORED },
+          .eventid = QFILE_MONITOR_EVENT_IGNORED,
+          .swapnext = true },
         { .type = QFILE_MONITOR_TEST_OP_EVENT,
           .filesrc = "fish", .watchid = &watch0,
           .eventid = QFILE_MONITOR_EVENT_DELETED },
@@ -493,8 +517,9 @@ test_file_monitor_events(void)
                 g_printerr("Event id=%" PRIx64 " event=%d file=%s\n",
                            *op->watchid, op->eventid, op->filesrc);
             }
-            if (!qemu_file_monitor_test_expect(
-                    &data, *op->watchid, op->eventid, op->filesrc))
+            if (!qemu_file_monitor_test_expect(&data, *op->watchid,
+                                               op->eventid, op->filesrc,
+                                               op->swapnext))
                 goto cleanup;
             break;
         case QFILE_MONITOR_TEST_OP_CREATE:
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#stable-4.13