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test-bdrv-drain: Test that bdrv_drain_invoke() doesn't poll

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This adds a test case that goes wrong if bdrv_drain_invoke() calls
aio_poll().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2018-03-23 20:10:52 +01:00
parent 0109e7e6f8
commit 57320ca961
1 changed files with 88 additions and 14 deletions
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102
tests/test-bdrv-drain.c
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@ -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)
@ -987,13 +1007,14 @@ 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);
@ -1001,6 +1022,25 @@ 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:
*
@ -1008,17 +1048,25 @@ 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 = {
@ -1027,6 +1075,12 @@ 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);
@ -1042,6 +1096,13 @@ 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);
@ -1049,7 +1110,9 @@ 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);
@ -1062,18 +1125,19 @@ 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);
@ -1081,8 +1145,8 @@ 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);
@ -1110,6 +1174,15 @@ 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)
{
@ -1162,6 +1235,7 @@ 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);