From 58476c0b2e67824bd2108055a315f8b9ebc54e31 Mon Sep 17 00:00:00 2001

From: Kevin Wolf <kwolf@redhat.com>

Date: Wed, 10 Oct 2018 20:21:42 +0100

Subject: [PATCH 16/49] test-bdrv-drain: Graph change through parent callback

RH-Author: Kevin Wolf <kwolf@redhat.com>

Message-id: <20181010202213.7372-4-kwolf@redhat.com>

Patchwork-id: 82595

O-Subject: [RHEL-8 qemu-kvm PATCH 13/44] test-bdrv-drain: Graph change through parent callback

Bugzilla: 1637976

RH-Acked-by: Max Reitz <mreitz@redhat.com>

RH-Acked-by: John Snow <jsnow@redhat.com>

RH-Acked-by: Thomas Huth <thuth@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

(cherry picked from commit 231281ab42dad2b407b941e36ad11cbc6586e937)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

---

 tests/test-bdrv-drain.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++++

 1 file changed, 130 insertions(+)

diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c

index 38706b0..f786326 100644

--- a/tests/test-bdrv-drain.c

+++ b/tests/test-bdrv-drain.c

@@ -977,6 +977,135 @@ static void test_detach_by_drain_subtree(void)

 }

+struct detach_by_parent_data {

+    BlockDriverState *parent_b;

+    BdrvChild *child_b;

+    BlockDriverState *c;

+    BdrvChild *child_c;

+};

+

+static void detach_by_parent_aio_cb(void *opaque, int ret)

+{

+    struct detach_by_parent_data *data = opaque;

+

+    g_assert_cmpint(ret, ==, 0);

+    bdrv_unref_child(data->parent_b, data->child_b);

+

+    bdrv_ref(data->c);

+    data->child_c = bdrv_attach_child(data->parent_b, data->c, "PB-C",

+                                      &child_file, &error_abort);

+}

+

+/*

+ * Initial graph:

+ *

+ * PA     PB

+ *    \ /   \

+ *     A     B     C

+ *

+ * PA has a pending write request whose callback changes the child nodes of PB:

+ * It removes B and adds C instead. The subtree of PB is drained, which will

+ * indirectly drain the write request, too.

+ */

+static void test_detach_by_parent_cb(void)

+{

+    BlockBackend *blk;

+    BlockDriverState *parent_a, *parent_b, *a, *b, *c;

+    BdrvChild *child_a, *child_b;

+    BlockAIOCB *acb;

+    struct detach_by_parent_data data;

+

+    QEMUIOVector qiov;

+    struct iovec iov = {

+        .iov_base = NULL,

+        .iov_len = 0,

+    };

+    qemu_iovec_init_external(&qiov, &iov, 1);

+

+    /* Create all involved nodes */

+    parent_a = bdrv_new_open_driver(&bdrv_test, "parent-a", BDRV_O_RDWR,

+                                    &error_abort);

+    parent_b = bdrv_new_open_driver(&bdrv_test, "parent-b", 0,

+                                    &error_abort);

+

+    a = bdrv_new_open_driver(&bdrv_test, "a", BDRV_O_RDWR, &error_abort);

+    b = bdrv_new_open_driver(&bdrv_test, "b", BDRV_O_RDWR, &error_abort);

+    c = bdrv_new_open_driver(&bdrv_test, "c", BDRV_O_RDWR, &error_abort);

+

+    /* blk is a BB for parent-a */

+    blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);

+    blk_insert_bs(blk, parent_a, &error_abort);

+    bdrv_unref(parent_a);

+

+    /* Set child relationships */

+    bdrv_ref(b);

+    bdrv_ref(a);

+    child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_file, &error_abort);

+    child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_backing, &error_abort);

+

+    bdrv_ref(a);

+    bdrv_attach_child(parent_a, a, "PA-A", &child_file, &error_abort);

+

+    g_assert_cmpint(parent_a->refcnt, ==, 1);

+    g_assert_cmpint(parent_b->refcnt, ==, 1);

+    g_assert_cmpint(a->refcnt, ==, 3);

+    g_assert_cmpint(b->refcnt, ==, 2);

+    g_assert_cmpint(c->refcnt, ==, 1);

+

+    g_assert(QLIST_FIRST(&parent_b->children) == child_a);

+    g_assert(QLIST_NEXT(child_a, next) == child_b);

+    g_assert(QLIST_NEXT(child_b, next) == NULL);

+

+    /* Start the evil write request */

+    data = (struct detach_by_parent_data) {

+        .parent_b = parent_b,

+        .child_b = child_b,

+        .c = c,

+    };

+    acb = blk_aio_preadv(blk, 0, &qiov, 0, detach_by_parent_aio_cb, &data);

+    g_assert(acb != NULL);

+

+    /* Drain and check the expected result */

+    bdrv_subtree_drained_begin(parent_b);

+

+    g_assert(data.child_c != NULL);

+

+    g_assert_cmpint(parent_a->refcnt, ==, 1);

+    g_assert_cmpint(parent_b->refcnt, ==, 1);

+    g_assert_cmpint(a->refcnt, ==, 3);

+    g_assert_cmpint(b->refcnt, ==, 1);

+    g_assert_cmpint(c->refcnt, ==, 2);

+

+    g_assert(QLIST_FIRST(&parent_b->children) == data.child_c);

+    g_assert(QLIST_NEXT(data.child_c, next) == child_a);

+    g_assert(QLIST_NEXT(child_a, next) == NULL);

+

+    g_assert_cmpint(parent_a->quiesce_counter, ==, 1);

+    g_assert_cmpint(parent_b->quiesce_counter, ==, 1);

+    g_assert_cmpint(a->quiesce_counter, ==, 1);

+    g_assert_cmpint(b->quiesce_counter, ==, 0);

+    g_assert_cmpint(c->quiesce_counter, ==, 1);

+

+    bdrv_subtree_drained_end(parent_b);

+

+    bdrv_unref(parent_b);

+    blk_unref(blk);

+

+    /* XXX Once bdrv_close() unref's children instead of just detaching them,

+     * this won't be necessary any more. */

+    bdrv_unref(a);

+    bdrv_unref(a);

+    bdrv_unref(c);

+

+    g_assert_cmpint(a->refcnt, ==, 1);

+    g_assert_cmpint(b->refcnt, ==, 1);

+    g_assert_cmpint(c->refcnt, ==, 1);

+    bdrv_unref(a);

+    bdrv_unref(b);

+    bdrv_unref(c);

+}

+

+

 int main(int argc, char **argv)

 {

     int ret;

@@ -1027,6 +1156,7 @@ int main(int argc, char **argv)

     g_test_add_func("/bdrv-drain/deletion/drain", test_delete_by_drain);

     g_test_add_func("/bdrv-drain/detach/drain", test_detach_by_drain);

     g_test_add_func("/bdrv-drain/detach/drain_subtree", test_detach_by_drain_subtree);

+    g_test_add_func("/bdrv-drain/detach/parent_cb", test_detach_by_parent_cb);

     ret = g_test_run();

     qemu_event_destroy(&done_event);

-- 

1.8.3.1