From 57320ca961c2e8488e1884b4ebbcb929b6901dc6 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 23 Mar 2018 20:10:52 +0100 Subject: [PATCH] test-bdrv-drain: Test that bdrv_drain_invoke() doesn't poll This adds a test case that goes wrong if bdrv_drain_invoke() calls aio_poll(). Signed-off-by: Kevin Wolf --- 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 abb287e597..5cc179a778 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) @@ -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);