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ab61335025
qemu-e2k/tests/unit/test-bdrv-drain.c
Stefan Hajnoczi ab61335025 block: drain from main loop thread in bdrv_co_yield_to_drain() 
For simplicity, always run BlockDevOps .drained_begin/end/poll()
callbacks in the main loop thread. This makes it easier to implement the
callbacks and avoids extra locks.

Move the function pointer declarations from the I/O Code section to the
Global State section for BlockDevOps, BdrvChildClass, and BlockDriver.

Narrow IO_OR_GS_CODE() to GLOBAL_STATE_CODE() where appropriate.

The test-bdrv-drain test case calls bdrv_drain() from an IOThread. This
is now only allowed from coroutine context, so update the test case to
run in a coroutine.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-11-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-05-30 17:32:02 +02:00

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/*
* Block node draining tests
*
* Copyright (c) 2017 Kevin Wolf <kwolf@redhat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "block/block_int.h"
#include "block/blockjob_int.h"
#include "sysemu/block-backend.h"
#include "qapi/error.h"
#include "qemu/main-loop.h"
#include "iothread.h"
static QemuEvent done_event;
typedef struct BDRVTestState {
int drain_count;
AioContext *bh_indirection_ctx;
bool sleep_in_drain_begin;
} BDRVTestState;
static void coroutine_fn sleep_in_drain_begin(void *opaque)
{
BlockDriverState *bs = opaque;
qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000);
bdrv_dec_in_flight(bs);
}
static void bdrv_test_drain_begin(BlockDriverState *bs)
{
BDRVTestState *s = bs->opaque;
s->drain_count++;
if (s->sleep_in_drain_begin) {
Coroutine *co = qemu_coroutine_create(sleep_in_drain_begin, bs);
bdrv_inc_in_flight(bs);
aio_co_enter(bdrv_get_aio_context(bs), co);
}
}
static void bdrv_test_drain_end(BlockDriverState *bs)
{
BDRVTestState *s = bs->opaque;
s->drain_count--;
}
static void bdrv_test_close(BlockDriverState *bs)
{
BDRVTestState *s = bs->opaque;
g_assert_cmpint(s->drain_count, >, 0);
}
static void co_reenter_bh(void *opaque)
{
aio_co_wake(opaque);
}
static int coroutine_fn bdrv_test_co_preadv(BlockDriverState *bs,
int64_t offset, int64_t bytes,
QEMUIOVector *qiov,
BdrvRequestFlags flags)
{
BDRVTestState *s = bs->opaque;
/* We want this request to stay until the polling loop in drain waits for
* it to complete. We need to sleep a while as bdrv_drain_invoke() comes
* first and polls its result, too, but it shouldn't accidentally complete
* this request yet. */
qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000);
if (s->bh_indirection_ctx) {
aio_bh_schedule_oneshot(s->bh_indirection_ctx, co_reenter_bh,
qemu_coroutine_self());
qemu_coroutine_yield();
}
return 0;
}
static int bdrv_test_change_backing_file(BlockDriverState *bs,
const char *backing_file,
const char *backing_fmt)
{
return 0;
}
static BlockDriver bdrv_test = {
.format_name = "test",
.instance_size = sizeof(BDRVTestState),
.supports_backing = true,
.bdrv_close = bdrv_test_close,
.bdrv_co_preadv = bdrv_test_co_preadv,
.bdrv_drain_begin = bdrv_test_drain_begin,
.bdrv_drain_end = bdrv_test_drain_end,
.bdrv_child_perm = bdrv_default_perms,
.bdrv_change_backing_file = bdrv_test_change_backing_file,
};
static void aio_ret_cb(void *opaque, int ret)
{
int *aio_ret = opaque;
*aio_ret = ret;
}
typedef struct CallInCoroutineData {
void (*entry)(void);
bool done;
} CallInCoroutineData;
static coroutine_fn void call_in_coroutine_entry(void *opaque)
{
CallInCoroutineData *data = opaque;
data->entry();
data->done = true;
}
static void call_in_coroutine(void (*entry)(void))
{
Coroutine *co;
CallInCoroutineData data = {
.entry = entry,
.done = false,
};
co = qemu_coroutine_create(call_in_coroutine_entry, &data);
qemu_coroutine_enter(co);
while (!data.done) {
aio_poll(qemu_get_aio_context(), true);
}
}
enum drain_type {
BDRV_DRAIN_ALL,
BDRV_DRAIN,
DRAIN_TYPE_MAX,
};
static void do_drain_begin(enum drain_type drain_type, BlockDriverState *bs)
{
switch (drain_type) {
case BDRV_DRAIN_ALL: bdrv_drain_all_begin(); break;
case BDRV_DRAIN: bdrv_drained_begin(bs); break;
default: g_assert_not_reached();
}
}
static void do_drain_end(enum drain_type drain_type, BlockDriverState *bs)
{
switch (drain_type) {
case BDRV_DRAIN_ALL: bdrv_drain_all_end(); break;
case BDRV_DRAIN: bdrv_drained_end(bs); break;
default: g_assert_not_reached();
}
}
static void do_drain_begin_unlocked(enum drain_type drain_type, BlockDriverState *bs)
{
if (drain_type != BDRV_DRAIN_ALL) {
aio_context_acquire(bdrv_get_aio_context(bs));
}
do_drain_begin(drain_type, bs);
if (drain_type != BDRV_DRAIN_ALL) {
aio_context_release(bdrv_get_aio_context(bs));
}
}
static BlockBackend * no_coroutine_fn test_setup(void)
{
BlockBackend *blk;
BlockDriverState *bs, *backing;
blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
&error_abort);
blk_insert_bs(blk, bs, &error_abort);
backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
bdrv_set_backing_hd(bs, backing, &error_abort);
bdrv_unref(backing);
bdrv_unref(bs);
return blk;
}
static void do_drain_end_unlocked(enum drain_type drain_type, BlockDriverState *bs)
{
if (drain_type != BDRV_DRAIN_ALL) {
aio_context_acquire(bdrv_get_aio_context(bs));
}
do_drain_end(drain_type, bs);
if (drain_type != BDRV_DRAIN_ALL) {
aio_context_release(bdrv_get_aio_context(bs));
}
}
static void test_drv_cb_common(BlockBackend *blk, enum drain_type drain_type,
bool recursive)
{
BlockDriverState *bs = blk_bs(blk);
BlockDriverState *backing = bs->backing->bs;
BDRVTestState *s, *backing_s;
BlockAIOCB *acb;
int aio_ret;
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0);
s = bs->opaque;
backing_s = backing->opaque;
/* Simple bdrv_drain_all_begin/end pair, check that CBs are called */
g_assert_cmpint(s->drain_count, ==, 0);
g_assert_cmpint(backing_s->drain_count, ==, 0);
do_drain_begin(drain_type, bs);
g_assert_cmpint(s->drain_count, ==, 1);
g_assert_cmpint(backing_s->drain_count, ==, !!recursive);
do_drain_end(drain_type, bs);
g_assert_cmpint(s->drain_count, ==, 0);
g_assert_cmpint(backing_s->drain_count, ==, 0);
/* Now do the same while a request is pending */
aio_ret = -EINPROGRESS;
acb = blk_aio_preadv(blk, 0, &qiov, 0, aio_ret_cb, &aio_ret);
g_assert(acb != NULL);
g_assert_cmpint(aio_ret, ==, -EINPROGRESS);
g_assert_cmpint(s->drain_count, ==, 0);
g_assert_cmpint(backing_s->drain_count, ==, 0);
do_drain_begin(drain_type, bs);
g_assert_cmpint(aio_ret, ==, 0);
g_assert_cmpint(s->drain_count, ==, 1);
g_assert_cmpint(backing_s->drain_count, ==, !!recursive);
do_drain_end(drain_type, bs);
g_assert_cmpint(s->drain_count, ==, 0);
g_assert_cmpint(backing_s->drain_count, ==, 0);
}
static void test_drv_cb_drain_all(void)
{
BlockBackend *blk = test_setup();
test_drv_cb_common(blk, BDRV_DRAIN_ALL, true);
blk_unref(blk);
}
static void test_drv_cb_drain(void)
{
BlockBackend *blk = test_setup();
test_drv_cb_common(blk, BDRV_DRAIN, false);
blk_unref(blk);
}
static void coroutine_fn test_drv_cb_co_drain_all_entry(void)
{
BlockBackend *blk = blk_all_next(NULL);
test_drv_cb_common(blk, BDRV_DRAIN_ALL, true);
}
static void test_drv_cb_co_drain_all(void)
{
BlockBackend *blk = test_setup();
call_in_coroutine(test_drv_cb_co_drain_all_entry);
blk_unref(blk);
}
static void coroutine_fn test_drv_cb_co_drain_entry(void)
{
BlockBackend *blk = blk_all_next(NULL);
test_drv_cb_common(blk, BDRV_DRAIN, false);
}
static void test_drv_cb_co_drain(void)
{
BlockBackend *blk = test_setup();
call_in_coroutine(test_drv_cb_co_drain_entry);
blk_unref(blk);
}
static void test_quiesce_common(BlockBackend *blk, enum drain_type drain_type,
bool recursive)
{
BlockDriverState *bs = blk_bs(blk);
BlockDriverState *backing = bs->backing->bs;
g_assert_cmpint(bs->quiesce_counter, ==, 0);
g_assert_cmpint(backing->quiesce_counter, ==, 0);
do_drain_begin(drain_type, bs);
if (drain_type == BDRV_DRAIN_ALL) {
g_assert_cmpint(bs->quiesce_counter, ==, 2);
} else {
g_assert_cmpint(bs->quiesce_counter, ==, 1);
}
g_assert_cmpint(backing->quiesce_counter, ==, !!recursive);
do_drain_end(drain_type, bs);
g_assert_cmpint(bs->quiesce_counter, ==, 0);
g_assert_cmpint(backing->quiesce_counter, ==, 0);
}
static void test_quiesce_drain_all(void)
{
BlockBackend *blk = test_setup();
test_quiesce_common(blk, BDRV_DRAIN_ALL, true);
blk_unref(blk);
}
static void test_quiesce_drain(void)
{
BlockBackend *blk = test_setup();
test_quiesce_common(blk, BDRV_DRAIN, false);
blk_unref(blk);
}
static void coroutine_fn test_quiesce_co_drain_all_entry(void)
{
BlockBackend *blk = blk_all_next(NULL);
test_quiesce_common(blk, BDRV_DRAIN_ALL, true);
}
static void test_quiesce_co_drain_all(void)
{
BlockBackend *blk = test_setup();
call_in_coroutine(test_quiesce_co_drain_all_entry);
blk_unref(blk);
}
static void coroutine_fn test_quiesce_co_drain_entry(void)
{
BlockBackend *blk = blk_all_next(NULL);
test_quiesce_common(blk, BDRV_DRAIN, false);
}
static void test_quiesce_co_drain(void)
{
BlockBackend *blk = test_setup();
call_in_coroutine(test_quiesce_co_drain_entry);
blk_unref(blk);
}
static void test_nested(void)
{
BlockBackend *blk;
BlockDriverState *bs, *backing;
BDRVTestState *s, *backing_s;
enum drain_type outer, inner;
blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
&error_abort);
s = bs->opaque;
blk_insert_bs(blk, bs, &error_abort);
backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
backing_s = backing->opaque;
bdrv_set_backing_hd(bs, backing, &error_abort);
for (outer = 0; outer < DRAIN_TYPE_MAX; outer++) {
for (inner = 0; inner < DRAIN_TYPE_MAX; inner++) {
int backing_quiesce = (outer == BDRV_DRAIN_ALL) +
(inner == BDRV_DRAIN_ALL);
g_assert_cmpint(bs->quiesce_counter, ==, 0);
g_assert_cmpint(backing->quiesce_counter, ==, 0);
g_assert_cmpint(s->drain_count, ==, 0);
g_assert_cmpint(backing_s->drain_count, ==, 0);
do_drain_begin(outer, bs);
do_drain_begin(inner, bs);
g_assert_cmpint(bs->quiesce_counter, ==, 2 + !!backing_quiesce);
g_assert_cmpint(backing->quiesce_counter, ==, backing_quiesce);
g_assert_cmpint(s->drain_count, ==, 1);
g_assert_cmpint(backing_s->drain_count, ==, !!backing_quiesce);
do_drain_end(inner, bs);
do_drain_end(outer, bs);
g_assert_cmpint(bs->quiesce_counter, ==, 0);
g_assert_cmpint(backing->quiesce_counter, ==, 0);
g_assert_cmpint(s->drain_count, ==, 0);
g_assert_cmpint(backing_s->drain_count, ==, 0);
}
}
bdrv_unref(backing);
bdrv_unref(bs);
blk_unref(blk);
}
static void test_graph_change_drain_all(void)
{
BlockBackend *blk_a, *blk_b;
BlockDriverState *bs_a, *bs_b;
BDRVTestState *a_s, *b_s;
/* Create node A with a BlockBackend */
blk_a = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR,
&error_abort);
a_s = bs_a->opaque;
blk_insert_bs(blk_a, bs_a, &error_abort);
g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
g_assert_cmpint(a_s->drain_count, ==, 0);
/* Call bdrv_drain_all_begin() */
bdrv_drain_all_begin();
g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
g_assert_cmpint(a_s->drain_count, ==, 1);
/* Create node B with a BlockBackend */
blk_b = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR,
&error_abort);
b_s = bs_b->opaque;
blk_insert_bs(blk_b, bs_b, &error_abort);
g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
g_assert_cmpint(a_s->drain_count, ==, 1);
g_assert_cmpint(b_s->drain_count, ==, 1);
/* Unref and finally delete node A */
blk_unref(blk_a);
g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
g_assert_cmpint(a_s->drain_count, ==, 1);
g_assert_cmpint(b_s->drain_count, ==, 1);
bdrv_unref(bs_a);
g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
g_assert_cmpint(b_s->drain_count, ==, 1);
/* End the drained section */
bdrv_drain_all_end();
g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
g_assert_cmpint(b_s->drain_count, ==, 0);
g_assert_cmpint(qemu_get_aio_context()->external_disable_cnt, ==, 0);
bdrv_unref(bs_b);
blk_unref(blk_b);
}
struct test_iothread_data {
BlockDriverState *bs;
enum drain_type drain_type;
int *aio_ret;
bool co_done;
};
static void coroutine_fn test_iothread_drain_co_entry(void *opaque)
{
struct test_iothread_data *data = opaque;
do_drain_begin(data->drain_type, data->bs);
g_assert_cmpint(*data->aio_ret, ==, 0);
do_drain_end(data->drain_type, data->bs);
data->co_done = true;
aio_wait_kick();
}
static void test_iothread_aio_cb(void *opaque, int ret)
{
int *aio_ret = opaque;
*aio_ret = ret;
qemu_event_set(&done_event);
}
static void test_iothread_main_thread_bh(void *opaque)
{
struct test_iothread_data *data = opaque;
/* Test that the AioContext is not yet locked in a random BH that is
* executed during drain, otherwise this would deadlock. */
aio_context_acquire(bdrv_get_aio_context(data->bs));
bdrv_flush(data->bs);
aio_context_release(bdrv_get_aio_context(data->bs));
}
/*
* Starts an AIO request on a BDS that runs in the AioContext of iothread 1.
* The request involves a BH on iothread 2 before it can complete.
*
* @drain_thread = 0 means that do_drain_begin/end are called from the main
* thread, @drain_thread = 1 means that they are called from iothread 1. Drain
* for this BDS cannot be called from iothread 2 because only the main thread
* may do cross-AioContext polling.
*/
static void test_iothread_common(enum drain_type drain_type, int drain_thread)
{
BlockBackend *blk;
BlockDriverState *bs;
BDRVTestState *s;
BlockAIOCB *acb;
Coroutine *co;
int aio_ret;
struct test_iothread_data data;
IOThread *a = iothread_new();
IOThread *b = iothread_new();
AioContext *ctx_a = iothread_get_aio_context(a);
AioContext *ctx_b = iothread_get_aio_context(b);
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0);
/* bdrv_drain_all() may only be called from the main loop thread */
if (drain_type == BDRV_DRAIN_ALL && drain_thread != 0) {
goto out;
}
blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
&error_abort);
s = bs->opaque;
blk_insert_bs(blk, bs, &error_abort);
blk_set_disable_request_queuing(blk, true);
blk_set_aio_context(blk, ctx_a, &error_abort);
aio_context_acquire(ctx_a);
s->bh_indirection_ctx = ctx_b;
aio_ret = -EINPROGRESS;
qemu_event_reset(&done_event);
if (drain_thread == 0) {
acb = blk_aio_preadv(blk, 0, &qiov, 0, test_iothread_aio_cb, &aio_ret);
} else {
acb = blk_aio_preadv(blk, 0, &qiov, 0, aio_ret_cb, &aio_ret);
}
g_assert(acb != NULL);
g_assert_cmpint(aio_ret, ==, -EINPROGRESS);
aio_context_release(ctx_a);
data = (struct test_iothread_data) {
.bs = bs,
.drain_type = drain_type,
.aio_ret = &aio_ret,
};
switch (drain_thread) {
case 0:
if (drain_type != BDRV_DRAIN_ALL) {
aio_context_acquire(ctx_a);
}
aio_bh_schedule_oneshot(ctx_a, test_iothread_main_thread_bh, &data);
/* The request is running on the IOThread a. Draining its block device
* will make sure that it has completed as far as the BDS is concerned,
* but the drain in this thread can continue immediately after
* bdrv_dec_in_flight() and aio_ret might be assigned only slightly
* later. */
do_drain_begin(drain_type, bs);
g_assert_cmpint(bs->in_flight, ==, 0);
if (drain_type != BDRV_DRAIN_ALL) {
aio_context_release(ctx_a);
}
qemu_event_wait(&done_event);
if (drain_type != BDRV_DRAIN_ALL) {
aio_context_acquire(ctx_a);
}
g_assert_cmpint(aio_ret, ==, 0);
do_drain_end(drain_type, bs);
if (drain_type != BDRV_DRAIN_ALL) {
aio_context_release(ctx_a);
}
break;
case 1:
co = qemu_coroutine_create(test_iothread_drain_co_entry, &data);
aio_co_enter(ctx_a, co);
AIO_WAIT_WHILE_UNLOCKED(NULL, !data.co_done);
break;
default:
g_assert_not_reached();
}
aio_context_acquire(ctx_a);
blk_set_aio_context(blk, qemu_get_aio_context(), &error_abort);
aio_context_release(ctx_a);
bdrv_unref(bs);
blk_unref(blk);
out:
iothread_join(a);
iothread_join(b);
}
static void test_iothread_drain_all(void)
{
test_iothread_common(BDRV_DRAIN_ALL, 0);
test_iothread_common(BDRV_DRAIN_ALL, 1);
}
static void test_iothread_drain(void)
{
test_iothread_common(BDRV_DRAIN, 0);
test_iothread_common(BDRV_DRAIN, 1);
}
typedef struct TestBlockJob {
BlockJob common;
BlockDriverState *bs;
int run_ret;
int prepare_ret;
bool running;
bool should_complete;
} TestBlockJob;
static int test_job_prepare(Job *job)
{
TestBlockJob *s = container_of(job, TestBlockJob, common.job);
/* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
bdrv_flush(s->bs);
return s->prepare_ret;
}
static void test_job_commit(Job *job)
{
TestBlockJob *s = container_of(job, TestBlockJob, common.job);
/* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
bdrv_flush(s->bs);
}
static void test_job_abort(Job *job)
{
TestBlockJob *s = container_of(job, TestBlockJob, common.job);
/* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
bdrv_flush(s->bs);
}
static int coroutine_fn test_job_run(Job *job, Error **errp)
{
TestBlockJob *s = container_of(job, TestBlockJob, common.job);
/* We are running the actual job code past the pause point in
* job_co_entry(). */
s->running = true;
job_transition_to_ready(&s->common.job);
while (!s->should_complete) {
/* Avoid job_sleep_ns() because it marks the job as !busy. We want to
* emulate some actual activity (probably some I/O) here so that drain
* has to wait for this activity to stop. */
qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 1000000);
job_pause_point(&s->common.job);
}
return s->run_ret;
}
static void test_job_complete(Job *job, Error **errp)
{
TestBlockJob *s = container_of(job, TestBlockJob, common.job);
s->should_complete = true;
}
BlockJobDriver test_job_driver = {
.job_driver = {
.instance_size = sizeof(TestBlockJob),
.free = block_job_free,
.user_resume = block_job_user_resume,
.run = test_job_run,
.complete = test_job_complete,
.prepare = test_job_prepare,
.commit = test_job_commit,
.abort = test_job_abort,
},
};
enum test_job_result {
TEST_JOB_SUCCESS,
TEST_JOB_FAIL_RUN,
TEST_JOB_FAIL_PREPARE,
};
enum test_job_drain_node {
TEST_JOB_DRAIN_SRC,
TEST_JOB_DRAIN_SRC_CHILD,
};
static void test_blockjob_common_drain_node(enum drain_type drain_type,
bool use_iothread,
enum test_job_result result,
enum test_job_drain_node drain_node)
{
BlockBackend *blk_src, *blk_target;
BlockDriverState *src, *src_backing, *src_overlay, *target, *drain_bs;
BlockJob *job;
TestBlockJob *tjob;
IOThread *iothread = NULL;
AioContext *ctx;
int ret;
src = bdrv_new_open_driver(&bdrv_test, "source", BDRV_O_RDWR,
&error_abort);
src_backing = bdrv_new_open_driver(&bdrv_test, "source-backing",
BDRV_O_RDWR, &error_abort);
src_overlay = bdrv_new_open_driver(&bdrv_test, "source-overlay",
BDRV_O_RDWR, &error_abort);
bdrv_set_backing_hd(src_overlay, src, &error_abort);
bdrv_unref(src);
bdrv_set_backing_hd(src, src_backing, &error_abort);
bdrv_unref(src_backing);
blk_src = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
blk_insert_bs(blk_src, src_overlay, &error_abort);
switch (drain_node) {
case TEST_JOB_DRAIN_SRC:
drain_bs = src;
break;
case TEST_JOB_DRAIN_SRC_CHILD:
drain_bs = src_backing;
break;
default:
g_assert_not_reached();
}
if (use_iothread) {
iothread = iothread_new();
ctx = iothread_get_aio_context(iothread);
blk_set_aio_context(blk_src, ctx, &error_abort);
} else {
ctx = qemu_get_aio_context();
}
target = bdrv_new_open_driver(&bdrv_test, "target", BDRV_O_RDWR,
&error_abort);
blk_target = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
blk_insert_bs(blk_target, target, &error_abort);
blk_set_allow_aio_context_change(blk_target, true);
aio_context_acquire(ctx);
tjob = block_job_create("job0", &test_job_driver, NULL, src,
0, BLK_PERM_ALL,
0, 0, NULL, NULL, &error_abort);
tjob->bs = src;
job = &tjob->common;
block_job_add_bdrv(job, "target", target, 0, BLK_PERM_ALL, &error_abort);
switch (result) {
case TEST_JOB_SUCCESS:
break;
case TEST_JOB_FAIL_RUN:
tjob->run_ret = -EIO;
break;
case TEST_JOB_FAIL_PREPARE:
tjob->prepare_ret = -EIO;
break;
}
aio_context_release(ctx);
job_start(&job->job);
if (use_iothread) {
/* job_co_entry() is run in the I/O thread, wait for the actual job
* code to start (we don't want to catch the job in the pause point in
* job_co_entry(). */
while (!tjob->running) {
aio_poll(qemu_get_aio_context(), false);
}
}
WITH_JOB_LOCK_GUARD() {
g_assert_cmpint(job->job.pause_count, ==, 0);
g_assert_false(job->job.paused);
g_assert_true(tjob->running);
g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
}
do_drain_begin_unlocked(drain_type, drain_bs);
WITH_JOB_LOCK_GUARD() {
if (drain_type == BDRV_DRAIN_ALL) {
/* bdrv_drain_all() drains both src and target */
g_assert_cmpint(job->job.pause_count, ==, 2);
} else {
g_assert_cmpint(job->job.pause_count, ==, 1);
}
g_assert_true(job->job.paused);
g_assert_false(job->job.busy); /* The job is paused */
}
do_drain_end_unlocked(drain_type, drain_bs);
if (use_iothread) {
/*
* Here we are waiting for the paused status to change,
* so don't bother protecting the read every time.
*
* paused is reset in the I/O thread, wait for it
*/
while (job->job.paused) {
aio_poll(qemu_get_aio_context(), false);
}
}
WITH_JOB_LOCK_GUARD() {
g_assert_cmpint(job->job.pause_count, ==, 0);
g_assert_false(job->job.paused);
g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
}
do_drain_begin_unlocked(drain_type, target);
WITH_JOB_LOCK_GUARD() {
if (drain_type == BDRV_DRAIN_ALL) {
/* bdrv_drain_all() drains both src and target */
g_assert_cmpint(job->job.pause_count, ==, 2);
} else {
g_assert_cmpint(job->job.pause_count, ==, 1);
}
g_assert_true(job->job.paused);
g_assert_false(job->job.busy); /* The job is paused */
}
do_drain_end_unlocked(drain_type, target);
if (use_iothread) {
/*
* Here we are waiting for the paused status to change,
* so don't bother protecting the read every time.
*
* paused is reset in the I/O thread, wait for it
*/
while (job->job.paused) {
aio_poll(qemu_get_aio_context(), false);
}
}
WITH_JOB_LOCK_GUARD() {
g_assert_cmpint(job->job.pause_count, ==, 0);
g_assert_false(job->job.paused);
g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
}
WITH_JOB_LOCK_GUARD() {
ret = job_complete_sync_locked(&job->job, &error_abort);
}
g_assert_cmpint(ret, ==, (result == TEST_JOB_SUCCESS ? 0 : -EIO));
aio_context_acquire(ctx);
if (use_iothread) {
blk_set_aio_context(blk_src, qemu_get_aio_context(), &error_abort);
assert(blk_get_aio_context(blk_target) == qemu_get_aio_context());
}
aio_context_release(ctx);
blk_unref(blk_src);
blk_unref(blk_target);
bdrv_unref(src_overlay);
bdrv_unref(target);
if (iothread) {
iothread_join(iothread);
}
}
static void test_blockjob_common(enum drain_type drain_type, bool use_iothread,
enum test_job_result result)
{
test_blockjob_common_drain_node(drain_type, use_iothread, result,
TEST_JOB_DRAIN_SRC);
test_blockjob_common_drain_node(drain_type, use_iothread, result,
TEST_JOB_DRAIN_SRC_CHILD);
}
static void test_blockjob_drain_all(void)
{
test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_SUCCESS);
}
static void test_blockjob_drain(void)
{
test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_SUCCESS);
}
static void test_blockjob_error_drain_all(void)
{
test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_RUN);
test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_PREPARE);
}
static void test_blockjob_error_drain(void)
{
test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_RUN);
test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_PREPARE);
}
static void test_blockjob_iothread_drain_all(void)
{
test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_SUCCESS);
}
static void test_blockjob_iothread_drain(void)
{
test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_SUCCESS);
}
static void test_blockjob_iothread_error_drain_all(void)
{
test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_RUN);
test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_PREPARE);
}
static void test_blockjob_iothread_error_drain(void)
{
test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_RUN);
test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_PREPARE);
}
typedef struct BDRVTestTopState {
BdrvChild *wait_child;
} BDRVTestTopState;
static void bdrv_test_top_close(BlockDriverState *bs)
{
BdrvChild *c, *next_c;
QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) {
bdrv_unref_child(bs, c);
}
}
static int coroutine_fn GRAPH_RDLOCK
bdrv_test_top_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
QEMUIOVector *qiov, BdrvRequestFlags flags)
{
BDRVTestTopState *tts = bs->opaque;
return bdrv_co_preadv(tts->wait_child, offset, bytes, qiov, flags);
}
static BlockDriver bdrv_test_top_driver = {
.format_name = "test_top_driver",
.instance_size = sizeof(BDRVTestTopState),
.bdrv_close = bdrv_test_top_close,
.bdrv_co_preadv = bdrv_test_top_co_preadv,
.bdrv_child_perm = bdrv_default_perms,
};
typedef struct TestCoDeleteByDrainData {
BlockBackend *blk;
bool detach_instead_of_delete;
bool done;
} TestCoDeleteByDrainData;
static void coroutine_fn test_co_delete_by_drain(void *opaque)
{
TestCoDeleteByDrainData *dbdd = opaque;
BlockBackend *blk = dbdd->blk;
BlockDriverState *bs = blk_bs(blk);
BDRVTestTopState *tts = bs->opaque;
void *buffer = g_malloc(65536);
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buffer, 65536);
/* Pretend some internal write operation from parent to child.
* Important: We have to read from the child, not from the parent!
* Draining works by first propagating it all up the tree to the
* root and then waiting for drainage from root to the leaves
* (protocol nodes). If we have a request waiting on the root,
* everything will be drained before we go back down the tree, but
* we do not want that. We want to be in the middle of draining
* when this following requests returns. */
bdrv_graph_co_rdlock();
bdrv_co_preadv(tts->wait_child, 0, 65536, &qiov, 0);
bdrv_graph_co_rdunlock();
g_assert_cmpint(bs->refcnt, ==, 1);
if (!dbdd->detach_instead_of_delete) {
blk_co_unref(blk);
} else {
BdrvChild *c, *next_c;
QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) {
bdrv_unref_child(bs, c);
}
}
dbdd->done = true;
g_free(buffer);
}
/**
* Test what happens when some BDS has some children, you drain one of
* them and this results in the BDS being deleted.
*
* If @detach_instead_of_delete is set, the BDS is not going to be
* deleted but will only detach all of its children.
*/
static void do_test_delete_by_drain(bool detach_instead_of_delete,
enum drain_type drain_type)
{
BlockBackend *blk;
BlockDriverState *bs, *child_bs, *null_bs;
BDRVTestTopState *tts;
TestCoDeleteByDrainData dbdd;
Coroutine *co;
bs = bdrv_new_open_driver(&bdrv_test_top_driver, "top", BDRV_O_RDWR,
&error_abort);
bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
tts = bs->opaque;
null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
&error_abort);
bdrv_attach_child(bs, null_bs, "null-child", &child_of_bds,
BDRV_CHILD_DATA, &error_abort);
/* This child will be the one to pass to requests through to, and
* it will stall until a drain occurs */
child_bs = bdrv_new_open_driver(&bdrv_test, "child", BDRV_O_RDWR,
&error_abort);
child_bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
/* Takes our reference to child_bs */
tts->wait_child = bdrv_attach_child(bs, child_bs, "wait-child",
&child_of_bds,
BDRV_CHILD_DATA | BDRV_CHILD_PRIMARY,
&error_abort);
/* This child is just there to be deleted
* (for detach_instead_of_delete == true) */
null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
&error_abort);
bdrv_attach_child(bs, null_bs, "null-child", &child_of_bds, BDRV_CHILD_DATA,
&error_abort);
blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
blk_insert_bs(blk, bs, &error_abort);
/* Referenced by blk now */
bdrv_unref(bs);
g_assert_cmpint(bs->refcnt, ==, 1);
g_assert_cmpint(child_bs->refcnt, ==, 1);
g_assert_cmpint(null_bs->refcnt, ==, 1);
dbdd = (TestCoDeleteByDrainData){
.blk = blk,
.detach_instead_of_delete = detach_instead_of_delete,
.done = false,
};
co = qemu_coroutine_create(test_co_delete_by_drain, &dbdd);
qemu_coroutine_enter(co);
/* Drain the child while the read operation is still pending.
* This should result in the operation finishing and
* test_co_delete_by_drain() resuming. Thus, @bs will be deleted
* and the coroutine will exit while this drain operation is still
* in progress. */
switch (drain_type) {
case BDRV_DRAIN:
bdrv_ref(child_bs);
bdrv_drain(child_bs);
bdrv_unref(child_bs);
break;
case BDRV_DRAIN_ALL:
bdrv_drain_all_begin();
bdrv_drain_all_end();
break;
default:
g_assert_not_reached();
}
while (!dbdd.done) {
aio_poll(qemu_get_aio_context(), true);
}
if (detach_instead_of_delete) {
/* Here, the reference has not passed over to the coroutine,
* so we have to delete the BB ourselves */
blk_unref(blk);
}
}
static void test_delete_by_drain(void)
{
do_test_delete_by_drain(false, BDRV_DRAIN);
}
static void test_detach_by_drain_all(void)
{
do_test_delete_by_drain(true, BDRV_DRAIN_ALL);
}
static void test_detach_by_drain(void)
{
do_test_delete_by_drain(true, BDRV_DRAIN);
}
struct detach_by_parent_data {
BlockDriverState *parent_b;
BdrvChild *child_b;
BlockDriverState *c;
BdrvChild *child_c;
bool by_parent_cb;
bool detach_on_drain;
};
static struct detach_by_parent_data detach_by_parent_data;
static void detach_indirect_bh(void *opaque)
{
struct detach_by_parent_data *data = opaque;
bdrv_dec_in_flight(data->child_b->bs);
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_of_bds, BDRV_CHILD_DATA,
&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) {
bdrv_inc_in_flight(data->child_b->bs);
detach_indirect_bh(data);
}
}
static void detach_by_driver_cb_drained_begin(BdrvChild *child)
{
struct detach_by_parent_data *data = &detach_by_parent_data;
if (!data->detach_on_drain) {
return;
}
data->detach_on_drain = false;
bdrv_inc_in_flight(data->child_b->bs);
aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
detach_indirect_bh, &detach_by_parent_data);
child_of_bds.drained_begin(child);
}
static BdrvChildClass detach_by_driver_cb_class;
/*
* Initial graph:
*
* PA PB
* \ / \
* A B C
*
* 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 BdrvChildClass 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_indirect(bool by_parent_cb)
{
BlockBackend *blk;
BlockDriverState *parent_a, *parent_b, *a, *b, *c;
BdrvChild *child_a, *child_b;
BlockAIOCB *acb;
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0);
if (!by_parent_cb) {
detach_by_driver_cb_class = child_of_bds;
detach_by_driver_cb_class.drained_begin =
detach_by_driver_cb_drained_begin;
detach_by_driver_cb_class.drained_end = NULL;
detach_by_driver_cb_class.drained_poll = NULL;
}
detach_by_parent_data = (struct detach_by_parent_data) {
.detach_on_drain = false,
};
/* 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(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
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);
child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_of_bds,
BDRV_CHILD_DATA, &error_abort);
child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_of_bds,
BDRV_CHILD_COW, &error_abort);
bdrv_ref(a);
bdrv_attach_child(parent_a, a, "PA-A",
by_parent_cb ? &child_of_bds : &detach_by_driver_cb_class,
BDRV_CHILD_DATA, &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 */
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,
.detach_on_drain = true,
};
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_drained_begin(parent_b);
bdrv_drained_begin(a);
bdrv_drained_begin(b);
bdrv_drained_begin(c);
g_assert(detach_by_parent_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) == 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);
g_assert_cmpint(parent_b->quiesce_counter, ==, 3);
g_assert_cmpint(a->quiesce_counter, ==, 1);
g_assert_cmpint(b->quiesce_counter, ==, 1);
g_assert_cmpint(c->quiesce_counter, ==, 1);
bdrv_drained_end(parent_b);
bdrv_drained_end(a);
bdrv_drained_end(b);
bdrv_drained_end(c);
bdrv_unref(parent_b);
blk_unref(blk);
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);
}
static void test_detach_by_parent_cb(void)
{
test_detach_indirect(true);
}
static void test_detach_by_driver_cb(void)
{
test_detach_indirect(false);
}
static void test_append_to_drained(void)
{
BlockBackend *blk;
BlockDriverState *base, *overlay;
BDRVTestState *base_s, *overlay_s;
blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
base = bdrv_new_open_driver(&bdrv_test, "base", BDRV_O_RDWR, &error_abort);
base_s = base->opaque;
blk_insert_bs(blk, base, &error_abort);
overlay = bdrv_new_open_driver(&bdrv_test, "overlay", BDRV_O_RDWR,
&error_abort);
overlay_s = overlay->opaque;
do_drain_begin(BDRV_DRAIN, base);
g_assert_cmpint(base->quiesce_counter, ==, 1);
g_assert_cmpint(base_s->drain_count, ==, 1);
g_assert_cmpint(base->in_flight, ==, 0);
bdrv_append(overlay, base, &error_abort);
g_assert_cmpint(base->in_flight, ==, 0);
g_assert_cmpint(overlay->in_flight, ==, 0);
g_assert_cmpint(base->quiesce_counter, ==, 1);
g_assert_cmpint(base_s->drain_count, ==, 1);
g_assert_cmpint(overlay->quiesce_counter, ==, 1);
g_assert_cmpint(overlay_s->drain_count, ==, 1);
do_drain_end(BDRV_DRAIN, base);
g_assert_cmpint(base->quiesce_counter, ==, 0);
g_assert_cmpint(base_s->drain_count, ==, 0);
g_assert_cmpint(overlay->quiesce_counter, ==, 0);
g_assert_cmpint(overlay_s->drain_count, ==, 0);
bdrv_unref(overlay);
bdrv_unref(base);
blk_unref(blk);
}
static void test_set_aio_context(void)
{
BlockDriverState *bs;
IOThread *a = iothread_new();
IOThread *b = iothread_new();
AioContext *ctx_a = iothread_get_aio_context(a);
AioContext *ctx_b = iothread_get_aio_context(b);
bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
&error_abort);
bdrv_drained_begin(bs);
bdrv_try_change_aio_context(bs, ctx_a, NULL, &error_abort);
aio_context_acquire(ctx_a);
bdrv_drained_end(bs);
bdrv_drained_begin(bs);
bdrv_try_change_aio_context(bs, ctx_b, NULL, &error_abort);
aio_context_release(ctx_a);
aio_context_acquire(ctx_b);
bdrv_try_change_aio_context(bs, qemu_get_aio_context(), NULL, &error_abort);
aio_context_release(ctx_b);
bdrv_drained_end(bs);
bdrv_unref(bs);
iothread_join(a);
iothread_join(b);
}
typedef struct TestDropBackingBlockJob {
BlockJob common;
bool should_complete;
bool *did_complete;
BlockDriverState *detach_also;
BlockDriverState *bs;
} TestDropBackingBlockJob;
static int coroutine_fn test_drop_backing_job_run(Job *job, Error **errp)
{
TestDropBackingBlockJob *s =
container_of(job, TestDropBackingBlockJob, common.job);
while (!s->should_complete) {
job_sleep_ns(job, 0);
}
return 0;
}
static void test_drop_backing_job_commit(Job *job)
{
TestDropBackingBlockJob *s =
container_of(job, TestDropBackingBlockJob, common.job);
bdrv_set_backing_hd(s->bs, NULL, &error_abort);
bdrv_set_backing_hd(s->detach_also, NULL, &error_abort);
*s->did_complete = true;
}
static const BlockJobDriver test_drop_backing_job_driver = {
.job_driver = {
.instance_size = sizeof(TestDropBackingBlockJob),
.free = block_job_free,
.user_resume = block_job_user_resume,
.run = test_drop_backing_job_run,
.commit = test_drop_backing_job_commit,
}
};
/**
* Creates a child node with three parent nodes on it, and then runs a
* block job on the final one, parent-node-2.
*
* The job is then asked to complete before a section where the child
* is drained.
*
* Ending this section will undrain the child's parents, first
* parent-node-2, then parent-node-1, then parent-node-0 -- the parent
* list is in reverse order of how they were added. Ending the drain
* on parent-node-2 will resume the job, thus completing it and
* scheduling job_exit().
*
* Ending the drain on parent-node-1 will poll the AioContext, which
* lets job_exit() and thus test_drop_backing_job_commit() run. That
* function first removes the child as parent-node-2's backing file.
*
* In old (and buggy) implementations, there are two problems with
* that:
* (A) bdrv_drain_invoke() polls for every node that leaves the
* drained section. This means that job_exit() is scheduled
* before the child has left the drained section. Its
* quiesce_counter is therefore still 1 when it is removed from
* parent-node-2.
*
* (B) bdrv_replace_child_noperm() calls drained_end() on the old
* child's parents as many times as the child is quiesced. This
* means it will call drained_end() on parent-node-2 once.
* Because parent-node-2 is no longer quiesced at this point, this
* will fail.
*
* bdrv_replace_child_noperm() therefore must call drained_end() on
* the parent only if it really is still drained because the child is
* drained.
*
* If removing child from parent-node-2 was successful (as it should
* be), test_drop_backing_job_commit() will then also remove the child
* from parent-node-0.
*
* With an old version of our drain infrastructure ((A) above), that
* resulted in the following flow:
*
* 1. child attempts to leave its drained section. The call recurses
* to its parents.
*
* 2. parent-node-2 leaves the drained section. Polling in
* bdrv_drain_invoke() will schedule job_exit().
*
* 3. parent-node-1 leaves the drained section. Polling in
* bdrv_drain_invoke() will run job_exit(), thus disconnecting
* parent-node-0 from the child node.
*
* 4. bdrv_parent_drained_end() uses a QLIST_FOREACH_SAFE() loop to
* iterate over the parents. Thus, it now accesses the BdrvChild
* object that used to connect parent-node-0 and the child node.
* However, that object no longer exists, so it accesses a dangling
* pointer.
*
* The solution is to only poll once when running a bdrv_drained_end()
* operation, specifically at the end when all drained_end()
* operations for all involved nodes have been scheduled.
* Note that this also solves (A) above, thus hiding (B).
*/
static void test_blockjob_commit_by_drained_end(void)
{
BlockDriverState *bs_child, *bs_parents[3];
TestDropBackingBlockJob *job;
bool job_has_completed = false;
int i;
bs_child = bdrv_new_open_driver(&bdrv_test, "child-node", BDRV_O_RDWR,
&error_abort);
for (i = 0; i < 3; i++) {
char name[32];
snprintf(name, sizeof(name), "parent-node-%i", i);
bs_parents[i] = bdrv_new_open_driver(&bdrv_test, name, BDRV_O_RDWR,
&error_abort);
bdrv_set_backing_hd(bs_parents[i], bs_child, &error_abort);
}
job = block_job_create("job", &test_drop_backing_job_driver, NULL,
bs_parents[2], 0, BLK_PERM_ALL, 0, 0, NULL, NULL,
&error_abort);
job->bs = bs_parents[2];
job->detach_also = bs_parents[0];
job->did_complete = &job_has_completed;
job_start(&job->common.job);
job->should_complete = true;
bdrv_drained_begin(bs_child);
g_assert(!job_has_completed);
bdrv_drained_end(bs_child);
aio_poll(qemu_get_aio_context(), false);
g_assert(job_has_completed);
bdrv_unref(bs_parents[0]);
bdrv_unref(bs_parents[1]);
bdrv_unref(bs_parents[2]);
bdrv_unref(bs_child);
}
typedef struct TestSimpleBlockJob {
BlockJob common;
bool should_complete;
bool *did_complete;
} TestSimpleBlockJob;
static int coroutine_fn test_simple_job_run(Job *job, Error **errp)
{
TestSimpleBlockJob *s = container_of(job, TestSimpleBlockJob, common.job);
while (!s->should_complete) {
job_sleep_ns(job, 0);
}
return 0;
}
static void test_simple_job_clean(Job *job)
{
TestSimpleBlockJob *s = container_of(job, TestSimpleBlockJob, common.job);
*s->did_complete = true;
}
static const BlockJobDriver test_simple_job_driver = {
.job_driver = {
.instance_size = sizeof(TestSimpleBlockJob),
.free = block_job_free,
.user_resume = block_job_user_resume,
.run = test_simple_job_run,
.clean = test_simple_job_clean,
},
};
static int drop_intermediate_poll_update_filename(BdrvChild *child,
BlockDriverState *new_base,
const char *filename,
Error **errp)
{
/*
* We are free to poll here, which may change the block graph, if
* it is not drained.
*/
/* If the job is not drained: Complete it, schedule job_exit() */
aio_poll(qemu_get_current_aio_context(), false);
/* If the job is not drained: Run job_exit(), finish the job */
aio_poll(qemu_get_current_aio_context(), false);
return 0;
}
/**
* Test a poll in the midst of bdrv_drop_intermediate().
*
* bdrv_drop_intermediate() calls BdrvChildClass.update_filename(),
* which can yield or poll. This may lead to graph changes, unless
* the whole subtree in question is drained.
*
* We test this on the following graph:
*
* Job
*
* |
* job-node
* |
* v
*
* job-node
*
* |
* backing
* |
* v
*
* node-2 --chain--> node-1 --chain--> node-0
*
* We drop node-1 with bdrv_drop_intermediate(top=node-1, base=node-0).
*
* This first updates node-2's backing filename by invoking
* drop_intermediate_poll_update_filename(), which polls twice. This
* causes the job to finish, which in turns causes the job-node to be
* deleted.
*
* bdrv_drop_intermediate() uses a QLIST_FOREACH_SAFE() loop, so it
* already has a pointer to the BdrvChild edge between job-node and
* node-1. When it tries to handle that edge, we probably get a
* segmentation fault because the object no longer exists.
*
*
* The solution is for bdrv_drop_intermediate() to drain top's
* subtree. This prevents graph changes from happening just because
* BdrvChildClass.update_filename() yields or polls. Thus, the block
* job is paused during that drained section and must finish before or
* after.
*
* (In addition, bdrv_replace_child() must keep the job paused.)
*/
static void test_drop_intermediate_poll(void)
{
static BdrvChildClass chain_child_class;
BlockDriverState *chain[3];
TestSimpleBlockJob *job;
BlockDriverState *job_node;
bool job_has_completed = false;
int i;
int ret;
chain_child_class = child_of_bds;
chain_child_class.update_filename = drop_intermediate_poll_update_filename;
for (i = 0; i < 3; i++) {
char name[32];
snprintf(name, 32, "node-%i", i);
chain[i] = bdrv_new_open_driver(&bdrv_test, name, 0, &error_abort);
}
job_node = bdrv_new_open_driver(&bdrv_test, "job-node", BDRV_O_RDWR,
&error_abort);
bdrv_set_backing_hd(job_node, chain[1], &error_abort);
/*
* Establish the chain last, so the chain links are the first
* elements in the BDS.parents lists
*/
for (i = 0; i < 3; i++) {
if (i) {
/* Takes the reference to chain[i - 1] */
bdrv_attach_child(chain[i], chain[i - 1], "chain",
&chain_child_class, BDRV_CHILD_COW, &error_abort);
}
}
job = block_job_create("job", &test_simple_job_driver, NULL, job_node,
0, BLK_PERM_ALL, 0, 0, NULL, NULL, &error_abort);
/* The job has a reference now */
bdrv_unref(job_node);
job->did_complete = &job_has_completed;
job_start(&job->common.job);
job->should_complete = true;
g_assert(!job_has_completed);
ret = bdrv_drop_intermediate(chain[1], chain[0], NULL);
aio_poll(qemu_get_aio_context(), false);
g_assert(ret == 0);
g_assert(job_has_completed);
bdrv_unref(chain[2]);
}
typedef struct BDRVReplaceTestState {
bool setup_completed;
bool was_drained;
bool was_undrained;
bool has_read;
int drain_count;
bool yield_before_read;
Coroutine *io_co;
Coroutine *drain_co;
} BDRVReplaceTestState;
static void bdrv_replace_test_close(BlockDriverState *bs)
{
}
/**
* If @bs has a backing file:
* Yield if .yield_before_read is true (and wait for drain_begin to
* wake us up).
* Forward the read to bs->backing. Set .has_read to true.
* If drain_begin has woken us, wake it in turn.
*
* Otherwise:
* Set .has_read to true and return success.
*/
static int coroutine_fn GRAPH_RDLOCK
bdrv_replace_test_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
QEMUIOVector *qiov, BdrvRequestFlags flags)
{
BDRVReplaceTestState *s = bs->opaque;
if (bs->backing) {
int ret;
g_assert(!s->drain_count);
s->io_co = qemu_coroutine_self();
if (s->yield_before_read) {
s->yield_before_read = false;
qemu_coroutine_yield();
}
s->io_co = NULL;
ret = bdrv_co_preadv(bs->backing, offset, bytes, qiov, 0);
s->has_read = true;
/* Wake up drain_co if it runs */
if (s->drain_co) {
aio_co_wake(s->drain_co);
}
return ret;
}
s->has_read = true;
return 0;
}
static void coroutine_fn bdrv_replace_test_drain_co(void *opaque)
{
BlockDriverState *bs = opaque;
BDRVReplaceTestState *s = bs->opaque;
/* Keep waking io_co up until it is done */
while (s->io_co) {
aio_co_wake(s->io_co);
s->io_co = NULL;
qemu_coroutine_yield();
}
s->drain_co = NULL;
bdrv_dec_in_flight(bs);
}
/**
* If .drain_count is 0, wake up .io_co if there is one; and set
* .was_drained.
* Increment .drain_count.
*/
static void bdrv_replace_test_drain_begin(BlockDriverState *bs)
{
BDRVReplaceTestState *s = bs->opaque;
if (!s->setup_completed) {
return;
}
if (!s->drain_count) {
s->drain_co = qemu_coroutine_create(bdrv_replace_test_drain_co, bs);
bdrv_inc_in_flight(bs);
aio_co_enter(bdrv_get_aio_context(bs), s->drain_co);
s->was_drained = true;
}
s->drain_count++;
}
static void coroutine_fn bdrv_replace_test_read_entry(void *opaque)
{
BlockDriverState *bs = opaque;
char data;
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, &data, 1);
int ret;
/* Queue a read request post-drain */
bdrv_graph_co_rdlock();
ret = bdrv_replace_test_co_preadv(bs, 0, 1, &qiov, 0);
bdrv_graph_co_rdunlock();
g_assert(ret >= 0);
bdrv_dec_in_flight(bs);
}
/**
* Reduce .drain_count, set .was_undrained once it reaches 0.
* If .drain_count reaches 0 and the node has a backing file, issue a
* read request.
*/
static void bdrv_replace_test_drain_end(BlockDriverState *bs)
{
BDRVReplaceTestState *s = bs->opaque;
if (!s->setup_completed) {
return;
}
g_assert(s->drain_count > 0);
if (!--s->drain_count) {
s->was_undrained = true;
if (bs->backing) {
Coroutine *co = qemu_coroutine_create(bdrv_replace_test_read_entry,
bs);
bdrv_inc_in_flight(bs);
aio_co_enter(bdrv_get_aio_context(bs), co);
}
}
}
static BlockDriver bdrv_replace_test = {
.format_name = "replace_test",
.instance_size = sizeof(BDRVReplaceTestState),
.supports_backing = true,
.bdrv_close = bdrv_replace_test_close,
.bdrv_co_preadv = bdrv_replace_test_co_preadv,
.bdrv_drain_begin = bdrv_replace_test_drain_begin,
.bdrv_drain_end = bdrv_replace_test_drain_end,
.bdrv_child_perm = bdrv_default_perms,
};
static void coroutine_fn test_replace_child_mid_drain_read_co(void *opaque)
{
int ret;
char data;
ret = blk_co_pread(opaque, 0, 1, &data, 0);
g_assert(ret >= 0);
}
/**
* We test two things:
* (1) bdrv_replace_child_noperm() must not undrain the parent if both
* children are drained.
* (2) bdrv_replace_child_noperm() must never flush I/O requests to a
* drained child. If the old child is drained, it must flush I/O
* requests after the new one has been attached. If the new child
* is drained, it must flush I/O requests before the old one is
* detached.
*
* To do so, we create one parent node and two child nodes; then
* attach one of the children (old_child_bs) to the parent, then
* drain both old_child_bs and new_child_bs according to
* old_drain_count and new_drain_count, respectively, and finally
* we invoke bdrv_replace_node() to replace old_child_bs by
* new_child_bs.
*
* The test block driver we use here (bdrv_replace_test) has a read
* function that:
* - For the parent node, can optionally yield, and then forwards the
* read to bdrv_preadv(),
* - For the child node, just returns immediately.
*
* If the read yields, the drain_begin function will wake it up.
*
* The drain_end function issues a read on the parent once it is fully
* undrained (which simulates requests starting to come in again).
*/
static void do_test_replace_child_mid_drain(int old_drain_count,
int new_drain_count)
{
BlockBackend *parent_blk;
BlockDriverState *parent_bs;
BlockDriverState *old_child_bs, *new_child_bs;
BDRVReplaceTestState *parent_s;
BDRVReplaceTestState *old_child_s, *new_child_s;
Coroutine *io_co;
int i;
parent_bs = bdrv_new_open_driver(&bdrv_replace_test, "parent", 0,
&error_abort);
parent_s = parent_bs->opaque;
parent_blk = blk_new(qemu_get_aio_context(),
BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
blk_insert_bs(parent_blk, parent_bs, &error_abort);
old_child_bs = bdrv_new_open_driver(&bdrv_replace_test, "old-child", 0,
&error_abort);
new_child_bs = bdrv_new_open_driver(&bdrv_replace_test, "new-child", 0,
&error_abort);
old_child_s = old_child_bs->opaque;
new_child_s = new_child_bs->opaque;
/* So that we can read something */
parent_bs->total_sectors = 1;
old_child_bs->total_sectors = 1;
new_child_bs->total_sectors = 1;
bdrv_ref(old_child_bs);
bdrv_attach_child(parent_bs, old_child_bs, "child", &child_of_bds,
BDRV_CHILD_COW, &error_abort);
parent_s->setup_completed = true;
for (i = 0; i < old_drain_count; i++) {
bdrv_drained_begin(old_child_bs);
}
for (i = 0; i < new_drain_count; i++) {
bdrv_drained_begin(new_child_bs);
}
if (!old_drain_count) {
/*
* Start a read operation that will yield, so it will not
* complete before the node is drained.
*/
parent_s->yield_before_read = true;
io_co = qemu_coroutine_create(test_replace_child_mid_drain_read_co,
parent_blk);
qemu_coroutine_enter(io_co);
}
/* If we have started a read operation, it should have yielded */
g_assert(!parent_s->has_read);
/* Reset drained status so we can see what bdrv_replace_node() does */
parent_s->was_drained = false;
parent_s->was_undrained = false;
g_assert(parent_bs->quiesce_counter == old_drain_count);
bdrv_replace_node(old_child_bs, new_child_bs, &error_abort);
g_assert(parent_bs->quiesce_counter == new_drain_count);
if (!old_drain_count && !new_drain_count) {
/*
* From undrained to undrained drains and undrains the parent,
* because bdrv_replace_node() contains a drained section for
* @old_child_bs.
*/
g_assert(parent_s->was_drained && parent_s->was_undrained);
} else if (!old_drain_count && new_drain_count) {
/*
* From undrained to drained should drain the parent and keep
* it that way.
*/
g_assert(parent_s->was_drained && !parent_s->was_undrained);
} else if (old_drain_count && !new_drain_count) {
/*
* From drained to undrained should undrain the parent and
* keep it that way.
*/
g_assert(!parent_s->was_drained && parent_s->was_undrained);
} else /* if (old_drain_count && new_drain_count) */ {
/*
* From drained to drained must not undrain the parent at any
* point
*/
g_assert(!parent_s->was_drained && !parent_s->was_undrained);
}
if (!old_drain_count || !new_drain_count) {
/*
* If !old_drain_count, we have started a read request before
* bdrv_replace_node(). If !new_drain_count, the parent must
* have been undrained at some point, and
* bdrv_replace_test_co_drain_end() starts a read request
* then.
*/
g_assert(parent_s->has_read);
} else {
/*
* If the parent was never undrained, there is no way to start
* a read request.
*/
g_assert(!parent_s->has_read);
}
/* A drained child must have not received any request */
g_assert(!(old_drain_count && old_child_s->has_read));
g_assert(!(new_drain_count && new_child_s->has_read));
for (i = 0; i < new_drain_count; i++) {
bdrv_drained_end(new_child_bs);
}
for (i = 0; i < old_drain_count; i++) {
bdrv_drained_end(old_child_bs);
}
/*
* By now, bdrv_replace_test_co_drain_end() must have been called
* at some point while the new child was attached to the parent.
*/
g_assert(parent_s->has_read);
g_assert(new_child_s->has_read);
blk_unref(parent_blk);
bdrv_unref(parent_bs);
bdrv_unref(old_child_bs);
bdrv_unref(new_child_bs);
}
static void test_replace_child_mid_drain(void)
{
int old_drain_count, new_drain_count;
for (old_drain_count = 0; old_drain_count < 2; old_drain_count++) {
for (new_drain_count = 0; new_drain_count < 2; new_drain_count++) {
do_test_replace_child_mid_drain(old_drain_count, new_drain_count);
}
}
}
int main(int argc, char **argv)
{
int ret;
bdrv_init();
qemu_init_main_loop(&error_abort);
g_test_init(&argc, &argv, NULL);
qemu_event_init(&done_event, false);
g_test_add_func("/bdrv-drain/driver-cb/drain_all", test_drv_cb_drain_all);
g_test_add_func("/bdrv-drain/driver-cb/drain", test_drv_cb_drain);
g_test_add_func("/bdrv-drain/driver-cb/co/drain_all",
test_drv_cb_co_drain_all);
g_test_add_func("/bdrv-drain/driver-cb/co/drain", test_drv_cb_co_drain);
g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all);
g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain);
g_test_add_func("/bdrv-drain/quiesce/co/drain_all",
test_quiesce_co_drain_all);
g_test_add_func("/bdrv-drain/quiesce/co/drain", test_quiesce_co_drain);
g_test_add_func("/bdrv-drain/nested", test_nested);
g_test_add_func("/bdrv-drain/graph-change/drain_all",
test_graph_change_drain_all);
g_test_add_func("/bdrv-drain/iothread/drain_all", test_iothread_drain_all);
g_test_add_func("/bdrv-drain/iothread/drain", test_iothread_drain);
g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all);
g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain);
g_test_add_func("/bdrv-drain/blockjob/error/drain_all",
test_blockjob_error_drain_all);
g_test_add_func("/bdrv-drain/blockjob/error/drain",
test_blockjob_error_drain);
g_test_add_func("/bdrv-drain/blockjob/iothread/drain_all",
test_blockjob_iothread_drain_all);
g_test_add_func("/bdrv-drain/blockjob/iothread/drain",
test_blockjob_iothread_drain);
g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain_all",
test_blockjob_iothread_error_drain_all);
g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain",
test_blockjob_iothread_error_drain);
g_test_add_func("/bdrv-drain/deletion/drain", test_delete_by_drain);
g_test_add_func("/bdrv-drain/detach/drain_all", test_detach_by_drain_all);
g_test_add_func("/bdrv-drain/detach/drain", test_detach_by_drain);
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);
g_test_add_func("/bdrv-drain/attach/drain", test_append_to_drained);
g_test_add_func("/bdrv-drain/set_aio_context", test_set_aio_context);
g_test_add_func("/bdrv-drain/blockjob/commit_by_drained_end",
test_blockjob_commit_by_drained_end);
g_test_add_func("/bdrv-drain/bdrv_drop_intermediate/poll",
test_drop_intermediate_poll);
g_test_add_func("/bdrv-drain/replace_child/mid-drain",
test_replace_child_mid_drain);
ret = g_test_run();
qemu_event_destroy(&done_event);
return ret;
}
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