From eae61f64dccec3d6e32a7ba8d934da629fdd8595 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Fri, 14 Sep 2018 10:55:13 +0200
Subject: [PATCH 22/49] test-bdrv-drain: Test that bdrv_drain_invoke() doesn't
poll
RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <20180914105540.18077-16-kwolf@redhat.com>
Patchwork-id: 82167
O-Subject: [RHV-7.6 qemu-kvm-rhev PATCH 15/42] test-bdrv-drain: Test that bdrv_drain_invoke() doesn't poll
Bugzilla: 1601212
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
This adds a test case that goes wrong if bdrv_drain_invoke() calls
aio_poll().
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 57320ca961c2e8488e1884b4ebbcb929b6901dc6)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
tests/test-bdrv-drain.c | 102 +++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 88 insertions(+), 14 deletions(-)
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index f786326..c4aa913 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -34,12 +34,16 @@ static QemuEvent done_event;
typedef struct BDRVTestState {
int drain_count;
AioContext *bh_indirection_ctx;
+ bool sleep_in_drain_begin;
} BDRVTestState;
static void coroutine_fn bdrv_test_co_drain_begin(BlockDriverState *bs)
{
BDRVTestState *s = bs->opaque;
s->drain_count++;
+ if (s->sleep_in_drain_begin) {
+ qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000);
+ }
}
static void coroutine_fn bdrv_test_co_drain_end(BlockDriverState *bs)
@@ -80,6 +84,22 @@ static int coroutine_fn bdrv_test_co_preadv(BlockDriverState *bs,
return 0;
}
+static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
+ const BdrvChildRole *role,
+ BlockReopenQueue *reopen_queue,
+ uint64_t perm, uint64_t shared,
+ uint64_t *nperm, uint64_t *nshared)
+{
+ /* bdrv_format_default_perms() accepts only these two, so disguise
+ * detach_by_driver_cb_role as one of them. */
+ if (role != &child_file && role != &child_backing) {
+ role = &child_file;
+ }
+
+ bdrv_format_default_perms(bs, c, role, reopen_queue, perm, shared,
+ nperm, nshared);
+}
+
static BlockDriver bdrv_test = {
.format_name = "test",
.instance_size = sizeof(BDRVTestState),
@@ -90,7 +110,7 @@ static BlockDriver bdrv_test = {
.bdrv_co_drain_begin = bdrv_test_co_drain_begin,
.bdrv_co_drain_end = bdrv_test_co_drain_end,
- .bdrv_child_perm = bdrv_format_default_perms,
+ .bdrv_child_perm = bdrv_test_child_perm,
};
static void aio_ret_cb(void *opaque, int ret)
@@ -982,13 +1002,14 @@ struct detach_by_parent_data {
BdrvChild *child_b;
BlockDriverState *c;
BdrvChild *child_c;
+ bool by_parent_cb;
};
+static struct detach_by_parent_data detach_by_parent_data;
-static void detach_by_parent_aio_cb(void *opaque, int ret)
+static void detach_indirect_bh(void *opaque)
{
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);
@@ -996,6 +1017,25 @@ static void detach_by_parent_aio_cb(void *opaque, int ret)
&child_file, &error_abort);
}
+static void detach_by_parent_aio_cb(void *opaque, int ret)
+{
+ struct detach_by_parent_data *data = &detach_by_parent_data;
+
+ g_assert_cmpint(ret, ==, 0);
+ if (data->by_parent_cb) {
+ detach_indirect_bh(data);
+ }
+}
+
+static void detach_by_driver_cb_drained_begin(BdrvChild *child)
+{
+ aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
+ detach_indirect_bh, &detach_by_parent_data);
+ child_file.drained_begin(child);
+}
+
+static BdrvChildRole detach_by_driver_cb_role;
+
/*
* Initial graph:
*
@@ -1003,17 +1043,25 @@ static void detach_by_parent_aio_cb(void *opaque, int ret)
* \ / \
* 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.
+ * by_parent_cb == true: Test that parent callbacks don't poll
+ *
+ * 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.
+ *
+ * by_parent_cb == false: Test that bdrv_drain_invoke() doesn't poll
+ *
+ * PA's BdrvChildRole has a .drained_begin callback that schedules a BH
+ * that does the same graph change. If bdrv_drain_invoke() calls it, the
+ * state is messed up, but if it is only polled in the single
+ * BDRV_POLL_WHILE() at the end of the drain, this should work fine.
*/
-static void test_detach_by_parent_cb(void)
+static void test_detach_indirect(bool by_parent_cb)
{
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 = {
@@ -1022,6 +1070,12 @@ static void test_detach_by_parent_cb(void)
};
qemu_iovec_init_external(&qiov, &iov, 1);
+ if (!by_parent_cb) {
+ detach_by_driver_cb_role = child_file;
+ detach_by_driver_cb_role.drained_begin =
+ detach_by_driver_cb_drained_begin;
+ }
+
/* Create all involved nodes */
parent_a = bdrv_new_open_driver(&bdrv_test, "parent-a", BDRV_O_RDWR,
&error_abort);
@@ -1037,6 +1091,13 @@ static void test_detach_by_parent_cb(void)
blk_insert_bs(blk, parent_a, &error_abort);
bdrv_unref(parent_a);
+ /* If we want to get bdrv_drain_invoke() to call aio_poll(), the driver
+ * callback must not return immediately. */
+ if (!by_parent_cb) {
+ BDRVTestState *s = parent_a->opaque;
+ s->sleep_in_drain_begin = true;
+ }
+
/* Set child relationships */
bdrv_ref(b);
bdrv_ref(a);
@@ -1044,7 +1105,9 @@ static void test_detach_by_parent_cb(void)
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);
+ bdrv_attach_child(parent_a, a, "PA-A",
+ by_parent_cb ? &child_file : &detach_by_driver_cb_role,
+ &error_abort);
g_assert_cmpint(parent_a->refcnt, ==, 1);
g_assert_cmpint(parent_b->refcnt, ==, 1);
@@ -1057,18 +1120,19 @@ static void test_detach_by_parent_cb(void)
g_assert(QLIST_NEXT(child_b, next) == NULL);
/* Start the evil write request */
- data = (struct detach_by_parent_data) {
+ detach_by_parent_data = (struct detach_by_parent_data) {
.parent_b = parent_b,
.child_b = child_b,
.c = c,
+ .by_parent_cb = by_parent_cb,
};
- acb = blk_aio_preadv(blk, 0, &qiov, 0, detach_by_parent_aio_cb, &data);
+ acb = blk_aio_preadv(blk, 0, &qiov, 0, detach_by_parent_aio_cb, NULL);
g_assert(acb != NULL);
/* Drain and check the expected result */
bdrv_subtree_drained_begin(parent_b);
- g_assert(data.child_c != NULL);
+ g_assert(detach_by_parent_data.child_c != NULL);
g_assert_cmpint(parent_a->refcnt, ==, 1);
g_assert_cmpint(parent_b->refcnt, ==, 1);
@@ -1076,8 +1140,8 @@ static void test_detach_by_parent_cb(void)
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_FIRST(&parent_b->children) == detach_by_parent_data.child_c);
+ g_assert(QLIST_NEXT(detach_by_parent_data.child_c, next) == child_a);
g_assert(QLIST_NEXT(child_a, next) == NULL);
g_assert_cmpint(parent_a->quiesce_counter, ==, 1);
@@ -1105,6 +1169,15 @@ static void test_detach_by_parent_cb(void)
bdrv_unref(c);
}
+static void test_detach_by_parent_cb(void)
+{
+ test_detach_indirect(true);
+}
+
+static void test_detach_by_driver_cb(void)
+{
+ test_detach_indirect(false);
+}
int main(int argc, char **argv)
{
@@ -1157,6 +1230,7 @@ int main(int argc, char **argv)
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);
+ g_test_add_func("/bdrv-drain/detach/driver_cb", test_detach_by_driver_cb);
ret = g_test_run();
qemu_event_destroy(&done_event);
--
1.8.3.1