From 5f50be9b5810293141bb53cfd0cb46e765367d56 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 9 Jun 2021 14:22:34 +0200 Subject: [PATCH 01/34] async: the main AioContext is only "current" if under the BQL If we want to wake up a coroutine from a worker thread, aio_co_wake() currently does not work. In that scenario, aio_co_wake() calls aio_co_enter(), but there is no current AioContext and therefore qemu_get_current_aio_context() returns the main thread. aio_co_wake() then attempts to call aio_context_acquire() instead of going through aio_co_schedule(). The default case of qemu_get_current_aio_context() was added to cover synchronous I/O started from the vCPU thread, but the main and vCPU threads are quite different. The main thread is an I/O thread itself, only running a more complicated event loop; the vCPU thread instead is essentially a worker thread that occasionally calls qemu_mutex_lock_iothread(). It is only in those critical sections that it acts as if it were the home thread of the main AioContext. Therefore, this patch detaches qemu_get_current_aio_context() from iothreads, which is a useless complication. The AioContext pointer is stored directly in the thread-local variable, including for the main loop. Worker threads (including vCPU threads) optionally behave as temporary home threads if they have taken the big QEMU lock, but if that is not the case they will always schedule coroutines on remote threads via aio_co_schedule(). With this change, the stub qemu_mutex_iothread_locked() must be changed from true to false. The previous value of true was needed because the main thread did not have an AioContext in the thread-local variable, but now it does have one. Reported-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Paolo Bonzini Message-Id: <20210609122234.544153-1-pbonzini@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy Tested-by: Vladimir Sementsov-Ogievskiy [eblake: tweak commit message per Vladimir's review] Signed-off-by: Eric Blake --- include/block/aio.h | 5 ++++- iothread.c | 9 +-------- stubs/iothread-lock.c | 2 +- stubs/iothread.c | 8 -------- stubs/meson.build | 1 - tests/unit/iothread.c | 9 +-------- util/async.c | 20 ++++++++++++++++++++ util/main-loop.c | 1 + 8 files changed, 28 insertions(+), 27 deletions(-) delete mode 100644 stubs/iothread.c diff --git a/include/block/aio.h b/include/block/aio.h index 5f342267d5..10fcae1515 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -691,10 +691,13 @@ void aio_co_enter(AioContext *ctx, struct Coroutine *co); * Return the AioContext whose event loop runs in the current thread. * * If called from an IOThread this will be the IOThread's AioContext. If - * called from another thread it will be the main loop AioContext. + * called from the main thread or with the "big QEMU lock" taken it + * will be the main loop AioContext. */ AioContext *qemu_get_current_aio_context(void); +void qemu_set_current_aio_context(AioContext *ctx); + /** * aio_context_setup: * @ctx: the aio context diff --git a/iothread.c b/iothread.c index 7f086387be..2c5ccd7367 100644 --- a/iothread.c +++ b/iothread.c @@ -39,13 +39,6 @@ DECLARE_CLASS_CHECKERS(IOThreadClass, IOTHREAD, #define IOTHREAD_POLL_MAX_NS_DEFAULT 0ULL #endif -static __thread IOThread *my_iothread; - -AioContext *qemu_get_current_aio_context(void) -{ - return my_iothread ? my_iothread->ctx : qemu_get_aio_context(); -} - static void *iothread_run(void *opaque) { IOThread *iothread = opaque; @@ -56,7 +49,7 @@ static void *iothread_run(void *opaque) * in this new thread uses glib. */ g_main_context_push_thread_default(iothread->worker_context); - my_iothread = iothread; + qemu_set_current_aio_context(iothread->ctx); iothread->thread_id = qemu_get_thread_id(); qemu_sem_post(&iothread->init_done_sem); diff --git a/stubs/iothread-lock.c b/stubs/iothread-lock.c index 2a6efad64a..5b45b7fc8b 100644 --- a/stubs/iothread-lock.c +++ b/stubs/iothread-lock.c @@ -3,7 +3,7 @@ bool qemu_mutex_iothread_locked(void) { - return true; + return false; } void qemu_mutex_lock_iothread_impl(const char *file, int line) diff --git a/stubs/iothread.c b/stubs/iothread.c deleted file mode 100644 index 8cc9e28c55..0000000000 --- a/stubs/iothread.c +++ /dev/null @@ -1,8 +0,0 @@ -#include "qemu/osdep.h" -#include "block/aio.h" -#include "qemu/main-loop.h" - -AioContext *qemu_get_current_aio_context(void) -{ - return qemu_get_aio_context(); -} diff --git a/stubs/meson.build b/stubs/meson.build index d4e9549dc9..2e79ff9f4d 100644 --- a/stubs/meson.build +++ b/stubs/meson.build @@ -16,7 +16,6 @@ stub_ss.add(files('fw_cfg.c')) stub_ss.add(files('gdbstub.c')) stub_ss.add(files('get-vm-name.c')) stub_ss.add(when: 'CONFIG_LINUX_IO_URING', if_true: files('io_uring.c')) -stub_ss.add(files('iothread.c')) stub_ss.add(files('iothread-lock.c')) stub_ss.add(files('isa-bus.c')) stub_ss.add(files('is-daemonized.c')) diff --git a/tests/unit/iothread.c b/tests/unit/iothread.c index afde12b4ef..f9b0791084 100644 --- a/tests/unit/iothread.c +++ b/tests/unit/iothread.c @@ -30,13 +30,6 @@ struct IOThread { bool stopping; }; -static __thread IOThread *my_iothread; - -AioContext *qemu_get_current_aio_context(void) -{ - return my_iothread ? my_iothread->ctx : qemu_get_aio_context(); -} - static void iothread_init_gcontext(IOThread *iothread) { GSource *source; @@ -54,9 +47,9 @@ static void *iothread_run(void *opaque) rcu_register_thread(); - my_iothread = iothread; qemu_mutex_lock(&iothread->init_done_lock); iothread->ctx = aio_context_new(&error_abort); + qemu_set_current_aio_context(iothread->ctx); /* * We must connect the ctx to a GMainContext, because in older versions diff --git a/util/async.c b/util/async.c index 674dbefb7c..5d9b7cc1eb 100644 --- a/util/async.c +++ b/util/async.c @@ -649,3 +649,23 @@ void aio_context_release(AioContext *ctx) { qemu_rec_mutex_unlock(&ctx->lock); } + +static __thread AioContext *my_aiocontext; + +AioContext *qemu_get_current_aio_context(void) +{ + if (my_aiocontext) { + return my_aiocontext; + } + if (qemu_mutex_iothread_locked()) { + /* Possibly in a vCPU thread. */ + return qemu_get_aio_context(); + } + return NULL; +} + +void qemu_set_current_aio_context(AioContext *ctx) +{ + assert(!my_aiocontext); + my_aiocontext = ctx; +} diff --git a/util/main-loop.c b/util/main-loop.c index d9c55df6f5..4ae5b23e99 100644 --- a/util/main-loop.c +++ b/util/main-loop.c @@ -170,6 +170,7 @@ int qemu_init_main_loop(Error **errp) if (!qemu_aio_context) { return -EMFILE; } + qemu_set_current_aio_context(qemu_aio_context); qemu_notify_bh = qemu_bh_new(notify_event_cb, NULL); gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD)); src = aio_get_g_source(qemu_aio_context); From 55159c34b8788ae00984341356d3ea4774912665 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 14 Jun 2021 13:02:14 +0200 Subject: [PATCH 02/34] tests: cover aio_co_enter from a worker thread without BQL taken Add a testcase for the test fixed by commit 'async: the main AioContext is only "current" if under the BQL. Signed-off-by: Paolo Bonzini Message-Id: <20210614110214.726722-1-pbonzini@redhat.com> Reviewed-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Eric Blake --- tests/unit/test-aio.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/tests/unit/test-aio.c b/tests/unit/test-aio.c index 8a46078463..6feeb9a4a9 100644 --- a/tests/unit/test-aio.c +++ b/tests/unit/test-aio.c @@ -877,6 +877,42 @@ static void test_queue_chaining(void) g_assert_cmpint(data_b.i, ==, data_b.max); } +static void co_check_current_thread(void *opaque) +{ + QemuThread *main_thread = opaque; + assert(qemu_thread_is_self(main_thread)); +} + +static void *test_aio_co_enter(void *co) +{ + /* + * qemu_get_current_aio_context() should not to be the main thread + * AioContext, because this is a worker thread that has not taken + * the BQL. So aio_co_enter will schedule the coroutine in the + * main thread AioContext. + */ + aio_co_enter(qemu_get_aio_context(), co); + return NULL; +} + +static void test_worker_thread_co_enter(void) +{ + QemuThread this_thread, worker_thread; + Coroutine *co; + + qemu_thread_get_self(&this_thread); + co = qemu_coroutine_create(co_check_current_thread, &this_thread); + + qemu_thread_create(&worker_thread, "test_acquire_thread", + test_aio_co_enter, + co, QEMU_THREAD_JOINABLE); + + /* Test aio_co_enter from a worker thread. */ + qemu_thread_join(&worker_thread); + g_assert(aio_poll(ctx, true)); + g_assert(!aio_poll(ctx, false)); +} + /* End of tests. */ int main(int argc, char **argv) @@ -903,6 +939,7 @@ int main(int argc, char **argv) g_test_add_func("/aio/timer/schedule", test_timer_schedule); g_test_add_func("/aio/coroutine/queue-chaining", test_queue_chaining); + g_test_add_func("/aio/coroutine/worker-thread-co-enter", test_worker_thread_co_enter); g_test_add_func("/aio-gsource/flush", test_source_flush); g_test_add_func("/aio-gsource/bh/schedule", test_source_bh_schedule); From 0e70260b65814fe7c016a63c3081ac39617294a0 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:31 +0300 Subject: [PATCH 03/34] co-queue: drop extra coroutine_fn marks qemu_co_queue_next() and qemu_co_queue_restart_all() just call aio_co_wake() which works well in non-coroutine context. So these functions can be called from non-coroutine context as well. And actually qemu_co_queue_restart_all() is called from nbd_cancel_in_flight(), which is called from non-coroutine context. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-2-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- include/qemu/coroutine.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h index 292e61aef0..4829ff373d 100644 --- a/include/qemu/coroutine.h +++ b/include/qemu/coroutine.h @@ -210,13 +210,15 @@ void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock); /** * Removes the next coroutine from the CoQueue, and wake it up. * Returns true if a coroutine was removed, false if the queue is empty. + * OK to run from coroutine and non-coroutine context. */ -bool coroutine_fn qemu_co_queue_next(CoQueue *queue); +bool qemu_co_queue_next(CoQueue *queue); /** * Empties the CoQueue; all coroutines are woken up. + * OK to run from coroutine and non-coroutine context. */ -void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue); +void qemu_co_queue_restart_all(CoQueue *queue); /** * Removes the next coroutine from the CoQueue, and wake it up. Unlike From 3687ad49038e13103f7382316e16dff79abddf95 Mon Sep 17 00:00:00 2001 From: Roman Kagan Date: Thu, 10 Jun 2021 13:07:32 +0300 Subject: [PATCH 04/34] block/nbd: fix channel object leak nbd_free_connect_thread leaks the channel object if it hasn't been stolen. Unref it and fix the leak. Signed-off-by: Roman Kagan Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-3-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 1 + 1 file changed, 1 insertion(+) diff --git a/block/nbd.c b/block/nbd.c index 616f9ae6c4..f4b3407587 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -381,6 +381,7 @@ static void nbd_free_connect_thread(NBDConnectThread *thr) { if (thr->sioc) { qio_channel_close(QIO_CHANNEL(thr->sioc), NULL); + object_unref(OBJECT(thr->sioc)); } error_free(thr->err); qapi_free_SocketAddress(thr->saddr); From bbba1c376b8b1ba5171bd14eb6bf212fa1173ddb Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:33 +0300 Subject: [PATCH 05/34] block/nbd: fix how state is cleared on nbd_open() failure paths We have two "return error" paths in nbd_open() after nbd_process_options(). Actually we should call nbd_clear_bdrvstate() on these paths. Interesting that nbd_process_options() calls nbd_clear_bdrvstate() by itself. Let's fix leaks and refactor things to be more obvious: - intialize yank at top of nbd_open() - move yank cleanup to nbd_clear_bdrvstate() - refactor nbd_open() so that all failure paths except for yank-register goes through nbd_clear_bdrvstate() Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Roman Kagan Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-4-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index f4b3407587..01d2c2efad 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -152,8 +152,12 @@ static void nbd_co_establish_connection_cancel(BlockDriverState *bs, static int nbd_client_handshake(BlockDriverState *bs, Error **errp); static void nbd_yank(void *opaque); -static void nbd_clear_bdrvstate(BDRVNBDState *s) +static void nbd_clear_bdrvstate(BlockDriverState *bs) { + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + + yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name)); + object_unref(OBJECT(s->tlscreds)); qapi_free_SocketAddress(s->saddr); s->saddr = NULL; @@ -2275,9 +2279,6 @@ static int nbd_process_options(BlockDriverState *bs, QDict *options, ret = 0; error: - if (ret < 0) { - nbd_clear_bdrvstate(s); - } qemu_opts_del(opts); return ret; } @@ -2288,11 +2289,6 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, int ret; BDRVNBDState *s = (BDRVNBDState *)bs->opaque; - ret = nbd_process_options(bs, options, errp); - if (ret < 0) { - return ret; - } - s->bs = bs; qemu_co_mutex_init(&s->send_mutex); qemu_co_queue_init(&s->free_sema); @@ -2301,20 +2297,23 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, return -EEXIST; } + ret = nbd_process_options(bs, options, errp); + if (ret < 0) { + goto fail; + } + /* * establish TCP connection, return error if it fails * TODO: Configurable retry-until-timeout behaviour. */ if (nbd_establish_connection(bs, s->saddr, errp) < 0) { - yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name)); - return -ECONNREFUSED; + ret = -ECONNREFUSED; + goto fail; } ret = nbd_client_handshake(bs, errp); if (ret < 0) { - yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name)); - nbd_clear_bdrvstate(s); - return ret; + goto fail; } /* successfully connected */ s->state = NBD_CLIENT_CONNECTED; @@ -2326,6 +2325,10 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, aio_co_schedule(bdrv_get_aio_context(bs), s->connection_co); return 0; + +fail: + nbd_clear_bdrvstate(bs); + return ret; } static int nbd_co_flush(BlockDriverState *bs) @@ -2369,11 +2372,8 @@ static void nbd_refresh_limits(BlockDriverState *bs, Error **errp) static void nbd_close(BlockDriverState *bs) { - BDRVNBDState *s = bs->opaque; - nbd_client_close(bs); - yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name)); - nbd_clear_bdrvstate(s); + nbd_clear_bdrvstate(bs); } /* From fb392b548eb4c6c2b2c7689e7fc6b1d2077d4f02 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:34 +0300 Subject: [PATCH 06/34] block/nbd: connect_thread_func(): do qio_channel_set_delay(false) nbd_open() does it (through nbd_establish_connection()). Actually we lost that call on reconnect path in 1dc4718d849e1a1fe "block/nbd: use non-blocking connect: fix vm hang on connect()" when we have introduced reconnect thread. Fixes: 1dc4718d849e1a1fe665ce5241ed79048cfa2cfc Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-5-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- block/nbd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/nbd.c b/block/nbd.c index 01d2c2efad..f3a036354d 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -408,6 +408,8 @@ static void *connect_thread_func(void *opaque) thr->sioc = NULL; } + qio_channel_set_delay(QIO_CHANNEL(thr->sioc), false); + qemu_mutex_lock(&thr->mutex); switch (thr->state) { From c5423704184c43cadd7b3c5ff0aea3925c5509bc Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:35 +0300 Subject: [PATCH 07/34] qemu-sockets: introduce socket_address_parse_named_fd() Add function that transforms named fd inside SocketAddress structure into number representation. This way it may be then used in a context where current monitor is not available. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-6-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake [eblake: comment tweak] Signed-off-by: Eric Blake --- include/qemu/sockets.h | 11 +++++++++++ util/qemu-sockets.c | 19 +++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h index 7d1f813576..0c34bf2398 100644 --- a/include/qemu/sockets.h +++ b/include/qemu/sockets.h @@ -111,4 +111,15 @@ SocketAddress *socket_remote_address(int fd, Error **errp); */ SocketAddress *socket_address_flatten(SocketAddressLegacy *addr); +/** + * socket_address_parse_named_fd: + * + * Modify @addr, replacing a named fd by its corresponding number. + * Needed for callers that plan to pass @addr to a context where the + * current monitor is not available. + * + * Return 0 on success. + */ +int socket_address_parse_named_fd(SocketAddress *addr, Error **errp); + #endif /* QEMU_SOCKETS_H */ diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c index c415c342c1..080a240b74 100644 --- a/util/qemu-sockets.c +++ b/util/qemu-sockets.c @@ -1164,6 +1164,25 @@ static int socket_get_fd(const char *fdstr, Error **errp) return fd; } +int socket_address_parse_named_fd(SocketAddress *addr, Error **errp) +{ + int fd; + + if (addr->type != SOCKET_ADDRESS_TYPE_FD) { + return 0; + } + + fd = socket_get_fd(addr->u.fd.str, errp); + if (fd < 0) { + return fd; + } + + g_free(addr->u.fd.str); + addr->u.fd.str = g_strdup_printf("%d", fd); + + return 0; +} + int socket_connect(SocketAddress *addr, Error **errp) { int fd; From 6cc702beac795a6de7b5f97700b140dcd9936055 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:36 +0300 Subject: [PATCH 08/34] block/nbd: call socket_address_parse_named_fd() in advance Detecting monitor by current coroutine works bad when we are not in coroutine context. And that's exactly so in nbd reconnect code, where qio_channel_socket_connect_sync() is called from thread. Monitor is needed only to parse named file descriptor. So, let's just parse it during nbd_open(), so that all further users of s->saddr don't need to access monitor. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-7-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- block/nbd.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/block/nbd.c b/block/nbd.c index f3a036354d..1c99654ef7 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -2140,6 +2140,12 @@ static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options, goto done; } + if (socket_address_parse_named_fd(saddr, errp) < 0) { + qapi_free_SocketAddress(saddr); + saddr = NULL; + goto done; + } + done: qobject_unref(addr); visit_free(iv); From e8b35bf5dc8d4e98d91855a9c7b2ed905c8e6888 Mon Sep 17 00:00:00 2001 From: Roman Kagan Date: Thu, 10 Jun 2021 13:07:37 +0300 Subject: [PATCH 09/34] block/nbd: ensure ->connection_thread is always valid Simplify lifetime management of BDRVNBDState->connect_thread by delaying the possible cleanup of it until the BDRVNBDState itself goes away. This also reverts 0267101af6 "block/nbd: fix possible use after free of s->connect_thread" as now s->connect_thread can't be cleared until the very end. Signed-off-by: Roman Kagan [vsementsov: rebase, revert 0267101af6 changes] Signed-off-by: Vladimir Sementsov-Ogievskiy [eblake: tweak comment] Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-8-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 56 ++++++++++++++++++++--------------------------------- 1 file changed, 21 insertions(+), 35 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 1c99654ef7..08ae47d83c 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -144,17 +144,31 @@ typedef struct BDRVNBDState { NBDConnectThread *connect_thread; } BDRVNBDState; +static void nbd_free_connect_thread(NBDConnectThread *thr); static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr, Error **errp); static int nbd_co_establish_connection(BlockDriverState *bs, Error **errp); -static void nbd_co_establish_connection_cancel(BlockDriverState *bs, - bool detach); +static void nbd_co_establish_connection_cancel(BlockDriverState *bs); static int nbd_client_handshake(BlockDriverState *bs, Error **errp); static void nbd_yank(void *opaque); static void nbd_clear_bdrvstate(BlockDriverState *bs) { BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + NBDConnectThread *thr = s->connect_thread; + bool thr_running; + + qemu_mutex_lock(&thr->mutex); + thr_running = thr->state == CONNECT_THREAD_RUNNING; + if (thr_running) { + thr->state = CONNECT_THREAD_RUNNING_DETACHED; + } + qemu_mutex_unlock(&thr->mutex); + + /* the runaway thread will clean up itself */ + if (!thr_running) { + nbd_free_connect_thread(thr); + } yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name)); @@ -295,7 +309,7 @@ static void coroutine_fn nbd_client_co_drain_begin(BlockDriverState *bs) s->drained = true; qemu_co_sleep_wake(&s->reconnect_sleep); - nbd_co_establish_connection_cancel(bs, false); + nbd_co_establish_connection_cancel(bs); reconnect_delay_timer_del(s); @@ -333,7 +347,7 @@ static void nbd_teardown_connection(BlockDriverState *bs) s->state = NBD_CLIENT_QUIT; if (s->connection_co) { qemu_co_sleep_wake(&s->reconnect_sleep); - nbd_co_establish_connection_cancel(bs, true); + nbd_co_establish_connection_cancel(bs); } if (qemu_in_coroutine()) { s->teardown_co = qemu_coroutine_self(); @@ -446,11 +460,6 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp) BDRVNBDState *s = bs->opaque; NBDConnectThread *thr = s->connect_thread; - if (!thr) { - /* detached */ - return -1; - } - qemu_mutex_lock(&thr->mutex); switch (thr->state) { @@ -494,12 +503,6 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp) s->wait_connect = true; qemu_coroutine_yield(); - if (!s->connect_thread) { - /* detached */ - return -1; - } - assert(thr == s->connect_thread); - qemu_mutex_lock(&thr->mutex); switch (thr->state) { @@ -547,18 +550,12 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp) * nbd_co_establish_connection_cancel * Cancel nbd_co_establish_connection asynchronously: it will finish soon, to * allow drained section to begin. - * - * If detach is true, also cleanup the state (or if thread is running, move it - * to CONNECT_THREAD_RUNNING_DETACHED state). s->connect_thread becomes NULL if - * detach is true. */ -static void nbd_co_establish_connection_cancel(BlockDriverState *bs, - bool detach) +static void nbd_co_establish_connection_cancel(BlockDriverState *bs) { BDRVNBDState *s = bs->opaque; NBDConnectThread *thr = s->connect_thread; bool wake = false; - bool do_free = false; qemu_mutex_lock(&thr->mutex); @@ -569,21 +566,10 @@ static void nbd_co_establish_connection_cancel(BlockDriverState *bs, s->wait_connect = false; wake = true; } - if (detach) { - thr->state = CONNECT_THREAD_RUNNING_DETACHED; - s->connect_thread = NULL; - } - } else if (detach) { - do_free = true; } qemu_mutex_unlock(&thr->mutex); - if (do_free) { - nbd_free_connect_thread(thr); - s->connect_thread = NULL; - } - if (wake) { aio_co_wake(s->connection_co); } @@ -2310,6 +2296,8 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } + nbd_init_connect_thread(s); + /* * establish TCP connection, return error if it fails * TODO: Configurable retry-until-timeout behaviour. @@ -2326,8 +2314,6 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, /* successfully connected */ s->state = NBD_CLIENT_CONNECTED; - nbd_init_connect_thread(s); - s->connection_co = qemu_coroutine_create(nbd_connection_entry, s); bdrv_inc_in_flight(bs); aio_co_schedule(bdrv_get_aio_context(bs), s->connection_co); From 2a25def4be09714c543713f111813b521b2356ee Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:38 +0300 Subject: [PATCH 10/34] block/nbd: nbd_client_handshake(): fix leak of s->ioc Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Roman Kagan Message-Id: <20210610100802.5888-9-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/nbd.c b/block/nbd.c index 08ae47d83c..77b85ca471 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -1889,6 +1889,8 @@ static int nbd_client_handshake(BlockDriverState *bs, Error **errp) nbd_yank, bs); object_unref(OBJECT(s->sioc)); s->sioc = NULL; + object_unref(OBJECT(s->ioc)); + s->ioc = NULL; return ret; } From 2def3edb4bdc6913c83b14beb0140c395e68ac17 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:39 +0300 Subject: [PATCH 11/34] block/nbd: BDRVNBDState: drop unused connect_err and connect_status These fields are write-only. Drop them. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Roman Kagan Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-10-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 77b85ca471..fdfb1ff7a1 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -121,8 +121,6 @@ typedef struct BDRVNBDState { bool wait_drained_end; int in_flight; NBDClientState state; - int connect_status; - Error *connect_err; bool wait_in_flight; QEMUTimer *reconnect_delay_timer; @@ -578,7 +576,6 @@ static void nbd_co_establish_connection_cancel(BlockDriverState *bs) static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) { int ret; - Error *local_err = NULL; if (!nbd_client_connecting(s)) { return; @@ -619,14 +616,14 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) s->ioc = NULL; } - if (nbd_co_establish_connection(s->bs, &local_err) < 0) { + if (nbd_co_establish_connection(s->bs, NULL) < 0) { ret = -ECONNREFUSED; goto out; } bdrv_dec_in_flight(s->bs); - ret = nbd_client_handshake(s->bs, &local_err); + ret = nbd_client_handshake(s->bs, NULL); if (s->drained) { s->wait_drained_end = true; @@ -641,11 +638,6 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) bdrv_inc_in_flight(s->bs); out: - s->connect_status = ret; - error_free(s->connect_err); - s->connect_err = NULL; - error_propagate(&s->connect_err, local_err); - if (ret >= 0) { /* successfully connected */ s->state = NBD_CLIENT_CONNECTED; From 08ea55d0681333c8c6475a82b71f7bc946042986 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:40 +0300 Subject: [PATCH 12/34] block/nbd: simplify waking of nbd_co_establish_connection() Instead of managing connect_bh, bh_ctx, and wait_connect fields, we can use a single link to the waiting coroutine with proper mutex protection. So new logic is: nbd_co_establish_connection() sets wait_co under the mutex, releases the mutex, then yield()s. Note that wait_co may be scheduled by the thread immediately after unlocking the mutex. Still, the main thread (or iothread) will not reach the code for entering the coroutine until the yield(), so we are safe. connect_thread_func() and nbd_co_establish_connection_cancel() do the following to handle wait_co: Under the mutex, if thr->wait_co is not NULL, make it NULL and schedule it. This way, we avoid scheduling the coroutine twice. Still scheduling is a bit different: In connect_thread_func() we can just call aio_co_wake under mutex, after commit [async: the main AioContext is only "current" if under the BQL] we are sure that aio_co_wake() will not try to acquire the aio context and do qemu_aio_coroutine_enter() but simply schedule the coroutine by aio_co_schedule(). nbd_co_establish_connection_cancel() will be called from non-coroutine context in further patch and will be able to go through qemu_aio_coroutine_enter() path of aio_co_wake(). So keep current behavior of waking the coroutine after the critical section. Also, this commit reduces the dependence of nbd_co_establish_connection() on the internals of bs (we now use a generic pointer to the coroutine, instead of direct use of s->connection_co). This is a step towards splitting the connection API out of nbd.c. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-11-vsementsov@virtuozzo.com> Reviewied-by: Eric Blake Signed-off-by: Eric Blake --- block/nbd.c | 55 +++++++++++++++-------------------------------------- 1 file changed, 15 insertions(+), 40 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index fdfb1ff7a1..653af62940 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -87,12 +87,6 @@ typedef enum NBDConnectThreadState { typedef struct NBDConnectThread { /* Initialization constants */ SocketAddress *saddr; /* address to connect to */ - /* - * Bottom half to schedule on completion. Scheduled only if bh_ctx is not - * NULL - */ - QEMUBHFunc *bh_func; - void *bh_opaque; /* * Result of last attempt. Valid in FAIL and SUCCESS states. @@ -101,10 +95,15 @@ typedef struct NBDConnectThread { QIOChannelSocket *sioc; Error *err; - /* state and bh_ctx are protected by mutex */ QemuMutex mutex; + /* All further fields are protected by mutex */ NBDConnectThreadState state; /* current state of the thread */ - AioContext *bh_ctx; /* where to schedule bh (NULL means don't schedule) */ + + /* + * wait_co: if non-NULL, which coroutine to wake in + * nbd_co_establish_connection() after yield() + */ + Coroutine *wait_co; } NBDConnectThread; typedef struct BDRVNBDState { @@ -138,7 +137,6 @@ typedef struct BDRVNBDState { char *x_dirty_bitmap; bool alloc_depth; - bool wait_connect; NBDConnectThread *connect_thread; } BDRVNBDState; @@ -370,15 +368,6 @@ static bool nbd_client_connecting_wait(BDRVNBDState *s) return qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTING_WAIT; } -static void connect_bh(void *opaque) -{ - BDRVNBDState *state = opaque; - - assert(state->wait_connect); - state->wait_connect = false; - aio_co_wake(state->connection_co); -} - static void nbd_init_connect_thread(BDRVNBDState *s) { s->connect_thread = g_new(NBDConnectThread, 1); @@ -386,8 +375,6 @@ static void nbd_init_connect_thread(BDRVNBDState *s) *s->connect_thread = (NBDConnectThread) { .saddr = QAPI_CLONE(SocketAddress, s->saddr), .state = CONNECT_THREAD_NONE, - .bh_func = connect_bh, - .bh_opaque = s, }; qemu_mutex_init(&s->connect_thread->mutex); @@ -427,11 +414,9 @@ static void *connect_thread_func(void *opaque) switch (thr->state) { case CONNECT_THREAD_RUNNING: thr->state = ret < 0 ? CONNECT_THREAD_FAIL : CONNECT_THREAD_SUCCESS; - if (thr->bh_ctx) { - aio_bh_schedule_oneshot(thr->bh_ctx, thr->bh_func, thr->bh_opaque); - - /* play safe, don't reuse bh_ctx on further connection attempts */ - thr->bh_ctx = NULL; + if (thr->wait_co) { + aio_co_wake(thr->wait_co); + thr->wait_co = NULL; } break; case CONNECT_THREAD_RUNNING_DETACHED: @@ -485,20 +470,14 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp) abort(); } - thr->bh_ctx = qemu_get_current_aio_context(); + thr->wait_co = qemu_coroutine_self(); qemu_mutex_unlock(&thr->mutex); - /* * We are going to wait for connect-thread finish, but * nbd_client_co_drain_begin() can interrupt. - * - * Note that wait_connect variable is not visible for connect-thread. It - * doesn't need mutex protection, it used only inside home aio context of - * bs. */ - s->wait_connect = true; qemu_coroutine_yield(); qemu_mutex_lock(&thr->mutex); @@ -553,23 +532,19 @@ static void nbd_co_establish_connection_cancel(BlockDriverState *bs) { BDRVNBDState *s = bs->opaque; NBDConnectThread *thr = s->connect_thread; - bool wake = false; + Coroutine *wait_co = NULL; qemu_mutex_lock(&thr->mutex); if (thr->state == CONNECT_THREAD_RUNNING) { /* We can cancel only in running state, when bh is not yet scheduled */ - thr->bh_ctx = NULL; - if (s->wait_connect) { - s->wait_connect = false; - wake = true; - } + wait_co = g_steal_pointer(&thr->wait_co); } qemu_mutex_unlock(&thr->mutex); - if (wake) { - aio_co_wake(s->connection_co); + if (wait_co) { + aio_co_wake(wait_co); } } From b8e8a3d116d2ba0f80ff47290604ece8c6ed09ca Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:41 +0300 Subject: [PATCH 13/34] block/nbd: drop thr->state We don't need all these states. The code refactored to use two boolean variables looks simpler. While moving the comment in nbd_co_establish_connection() rework it to give better information. Also, we are going to move the connection code to separate file and mentioning drained section would be confusing. Improve also the comment in NBDConnectThread, while dropping removed state names from it. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-12-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake [eblake: comment tweak] Signed-off-by: Eric Blake --- block/nbd.c | 140 +++++++++++++++++----------------------------------- 1 file changed, 45 insertions(+), 95 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 653af62940..f2d5b47026 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -66,38 +66,25 @@ typedef enum NBDClientState { NBD_CLIENT_QUIT } NBDClientState; -typedef enum NBDConnectThreadState { - /* No thread, no pending results */ - CONNECT_THREAD_NONE, - - /* Thread is running, no results for now */ - CONNECT_THREAD_RUNNING, - - /* - * Thread is running, but requestor exited. Thread should close - * the new socket and free the connect state on exit. - */ - CONNECT_THREAD_RUNNING_DETACHED, - - /* Thread finished, results are stored in a state */ - CONNECT_THREAD_FAIL, - CONNECT_THREAD_SUCCESS -} NBDConnectThreadState; - typedef struct NBDConnectThread { /* Initialization constants */ SocketAddress *saddr; /* address to connect to */ + QemuMutex mutex; + /* - * Result of last attempt. Valid in FAIL and SUCCESS states. - * If you want to steal error, don't forget to set pointer to NULL. + * @sioc and @err represent a connection attempt. While running + * is true, they are only used by the connection thread, and mutex + * locking is not needed. Once the thread finishes, + * nbd_co_establish_connection then steals these pointers while + * under the mutex. */ QIOChannelSocket *sioc; Error *err; - QemuMutex mutex; - /* All further fields are protected by mutex */ - NBDConnectThreadState state; /* current state of the thread */ + /* All further fields are accessed only under mutex */ + bool running; /* thread is running now */ + bool detached; /* thread is detached and should cleanup the state */ /* * wait_co: if non-NULL, which coroutine to wake in @@ -152,17 +139,19 @@ static void nbd_clear_bdrvstate(BlockDriverState *bs) { BDRVNBDState *s = (BDRVNBDState *)bs->opaque; NBDConnectThread *thr = s->connect_thread; - bool thr_running; + bool do_free = false; qemu_mutex_lock(&thr->mutex); - thr_running = thr->state == CONNECT_THREAD_RUNNING; - if (thr_running) { - thr->state = CONNECT_THREAD_RUNNING_DETACHED; + assert(!thr->detached); + if (thr->running) { + thr->detached = true; + } else { + do_free = true; } qemu_mutex_unlock(&thr->mutex); /* the runaway thread will clean up itself */ - if (!thr_running) { + if (do_free) { nbd_free_connect_thread(thr); } @@ -374,7 +363,6 @@ static void nbd_init_connect_thread(BDRVNBDState *s) *s->connect_thread = (NBDConnectThread) { .saddr = QAPI_CLONE(SocketAddress, s->saddr), - .state = CONNECT_THREAD_NONE, }; qemu_mutex_init(&s->connect_thread->mutex); @@ -395,7 +383,7 @@ static void *connect_thread_func(void *opaque) { NBDConnectThread *thr = opaque; int ret; - bool do_free = false; + bool do_free; thr->sioc = qio_channel_socket_new(); @@ -411,20 +399,13 @@ static void *connect_thread_func(void *opaque) qemu_mutex_lock(&thr->mutex); - switch (thr->state) { - case CONNECT_THREAD_RUNNING: - thr->state = ret < 0 ? CONNECT_THREAD_FAIL : CONNECT_THREAD_SUCCESS; - if (thr->wait_co) { - aio_co_wake(thr->wait_co); - thr->wait_co = NULL; - } - break; - case CONNECT_THREAD_RUNNING_DETACHED: - do_free = true; - break; - default: - abort(); + assert(thr->running); + thr->running = false; + if (thr->wait_co) { + aio_co_wake(thr->wait_co); + thr->wait_co = NULL; } + do_free = thr->detached; qemu_mutex_unlock(&thr->mutex); @@ -438,36 +419,24 @@ static void *connect_thread_func(void *opaque) static int coroutine_fn nbd_co_establish_connection(BlockDriverState *bs, Error **errp) { - int ret; QemuThread thread; BDRVNBDState *s = bs->opaque; NBDConnectThread *thr = s->connect_thread; + assert(!s->sioc); + qemu_mutex_lock(&thr->mutex); - switch (thr->state) { - case CONNECT_THREAD_FAIL: - case CONNECT_THREAD_NONE: + if (!thr->running) { + if (thr->sioc) { + /* Previous attempt finally succeeded in background */ + goto out; + } + thr->running = true; error_free(thr->err); thr->err = NULL; - thr->state = CONNECT_THREAD_RUNNING; qemu_thread_create(&thread, "nbd-connect", connect_thread_func, thr, QEMU_THREAD_DETACHED); - break; - case CONNECT_THREAD_SUCCESS: - /* Previous attempt finally succeeded in background */ - thr->state = CONNECT_THREAD_NONE; - s->sioc = thr->sioc; - thr->sioc = NULL; - yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), - nbd_yank, bs); - qemu_mutex_unlock(&thr->mutex); - return 0; - case CONNECT_THREAD_RUNNING: - /* Already running, will wait */ - break; - default: - abort(); } thr->wait_co = qemu_coroutine_self(); @@ -482,10 +451,16 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp) qemu_mutex_lock(&thr->mutex); - switch (thr->state) { - case CONNECT_THREAD_SUCCESS: - case CONNECT_THREAD_FAIL: - thr->state = CONNECT_THREAD_NONE; +out: + if (thr->running) { + /* + * The connection attempt was canceled and the coroutine resumed + * before the connection thread finished its job. Report the + * attempt as failed, but leave the connection thread running, + * to reuse it for the next connection attempt. + */ + error_setg(errp, "Connection attempt cancelled by other operation"); + } else { error_propagate(errp, thr->err); thr->err = NULL; s->sioc = thr->sioc; @@ -494,33 +469,11 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp) yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), nbd_yank, bs); } - ret = (s->sioc ? 0 : -1); - break; - case CONNECT_THREAD_RUNNING: - case CONNECT_THREAD_RUNNING_DETACHED: - /* - * Obviously, drained section wants to start. Report the attempt as - * failed. Still connect thread is executing in background, and its - * result may be used for next connection attempt. - */ - ret = -1; - error_setg(errp, "Connection attempt cancelled by other operation"); - break; - - case CONNECT_THREAD_NONE: - /* - * Impossible. We've seen this thread running. So it should be - * running or at least give some results. - */ - abort(); - - default: - abort(); } qemu_mutex_unlock(&thr->mutex); - return ret; + return s->sioc ? 0 : -1; } /* @@ -532,14 +485,11 @@ static void nbd_co_establish_connection_cancel(BlockDriverState *bs) { BDRVNBDState *s = bs->opaque; NBDConnectThread *thr = s->connect_thread; - Coroutine *wait_co = NULL; + Coroutine *wait_co; qemu_mutex_lock(&thr->mutex); - if (thr->state == CONNECT_THREAD_RUNNING) { - /* We can cancel only in running state, when bh is not yet scheduled */ - wait_co = g_steal_pointer(&thr->wait_co); - } + wait_co = g_steal_pointer(&thr->wait_co); qemu_mutex_unlock(&thr->mutex); From d33833d7af73641d26b836a40f0bc697b656859b Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:42 +0300 Subject: [PATCH 14/34] block/nbd: bs-independent interface for nbd_co_establish_connection() We are going to split connection code to a separate file. Now we are ready to give nbd_co_establish_connection() clean and bs-independent interface. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Roman Kagan Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-13-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 50 ++++++++++++++++++++++++++++++++------------------ 1 file changed, 32 insertions(+), 18 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index f2d5b47026..15b569a899 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -130,7 +130,8 @@ typedef struct BDRVNBDState { static void nbd_free_connect_thread(NBDConnectThread *thr); static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr, Error **errp); -static int nbd_co_establish_connection(BlockDriverState *bs, Error **errp); +static coroutine_fn QIOChannelSocket * +nbd_co_establish_connection(NBDConnectThread *thr, Error **errp); static void nbd_co_establish_connection_cancel(BlockDriverState *bs); static int nbd_client_handshake(BlockDriverState *bs, Error **errp); static void nbd_yank(void *opaque); @@ -416,22 +417,37 @@ static void *connect_thread_func(void *opaque) return NULL; } -static int coroutine_fn -nbd_co_establish_connection(BlockDriverState *bs, Error **errp) +/* + * Get a new connection in context of @thr: + * if the thread is running, wait for completion + * if the thread already succeeded in the background, and user didn't get the + * result, just return it now + * otherwise the thread is not running, so start a thread and wait for + * completion + */ +static coroutine_fn QIOChannelSocket * +nbd_co_establish_connection(NBDConnectThread *thr, Error **errp) { + QIOChannelSocket *sioc = NULL; QemuThread thread; - BDRVNBDState *s = bs->opaque; - NBDConnectThread *thr = s->connect_thread; - - assert(!s->sioc); qemu_mutex_lock(&thr->mutex); + /* + * Don't call nbd_co_establish_connection() in several coroutines in + * parallel. Only one call at once is supported. + */ + assert(!thr->wait_co); + if (!thr->running) { if (thr->sioc) { /* Previous attempt finally succeeded in background */ - goto out; + sioc = g_steal_pointer(&thr->sioc); + qemu_mutex_unlock(&thr->mutex); + + return sioc; } + thr->running = true; error_free(thr->err); thr->err = NULL; @@ -445,13 +461,12 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp) /* * We are going to wait for connect-thread finish, but - * nbd_client_co_drain_begin() can interrupt. + * nbd_co_establish_connection_cancel() can interrupt. */ qemu_coroutine_yield(); qemu_mutex_lock(&thr->mutex); -out: if (thr->running) { /* * The connection attempt was canceled and the coroutine resumed @@ -463,17 +478,12 @@ out: } else { error_propagate(errp, thr->err); thr->err = NULL; - s->sioc = thr->sioc; - thr->sioc = NULL; - if (s->sioc) { - yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), - nbd_yank, bs); - } + sioc = g_steal_pointer(&thr->sioc); } qemu_mutex_unlock(&thr->mutex); - return s->sioc ? 0 : -1; + return sioc; } /* @@ -541,11 +551,15 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) s->ioc = NULL; } - if (nbd_co_establish_connection(s->bs, NULL) < 0) { + s->sioc = nbd_co_establish_connection(s->connect_thread, NULL); + if (!s->sioc) { ret = -ECONNREFUSED; goto out; } + yank_register_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank, + s->bs); + bdrv_dec_in_flight(s->bs); ret = nbd_client_handshake(s->bs, NULL); From c3e77304855040ffd390cb7abaf7ec9ebb9b714c Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:43 +0300 Subject: [PATCH 15/34] block/nbd: make nbd_co_establish_connection_cancel() bs-independent nbd_co_establish_connection_cancel() actually needs only pointer to NBDConnectThread. So, make it clean. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Roman Kagan Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-14-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 15b569a899..bee615e5c4 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -132,7 +132,7 @@ static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr, Error **errp); static coroutine_fn QIOChannelSocket * nbd_co_establish_connection(NBDConnectThread *thr, Error **errp); -static void nbd_co_establish_connection_cancel(BlockDriverState *bs); +static void nbd_co_establish_connection_cancel(NBDConnectThread *thr); static int nbd_client_handshake(BlockDriverState *bs, Error **errp); static void nbd_yank(void *opaque); @@ -295,7 +295,7 @@ static void coroutine_fn nbd_client_co_drain_begin(BlockDriverState *bs) s->drained = true; qemu_co_sleep_wake(&s->reconnect_sleep); - nbd_co_establish_connection_cancel(bs); + nbd_co_establish_connection_cancel(s->connect_thread); reconnect_delay_timer_del(s); @@ -333,7 +333,7 @@ static void nbd_teardown_connection(BlockDriverState *bs) s->state = NBD_CLIENT_QUIT; if (s->connection_co) { qemu_co_sleep_wake(&s->reconnect_sleep); - nbd_co_establish_connection_cancel(bs); + nbd_co_establish_connection_cancel(s->connect_thread); } if (qemu_in_coroutine()) { s->teardown_co = qemu_coroutine_self(); @@ -488,13 +488,14 @@ nbd_co_establish_connection(NBDConnectThread *thr, Error **errp) /* * nbd_co_establish_connection_cancel - * Cancel nbd_co_establish_connection asynchronously: it will finish soon, to - * allow drained section to begin. + * Cancel nbd_co_establish_connection() asynchronously. + * + * Note that this function neither directly stops the thread nor closes the + * socket, but rather safely wakes nbd_co_establish_connection() which is + * sleeping in yield() */ -static void nbd_co_establish_connection_cancel(BlockDriverState *bs) +static void nbd_co_establish_connection_cancel(NBDConnectThread *thr) { - BDRVNBDState *s = bs->opaque; - NBDConnectThread *thr = s->connect_thread; Coroutine *wait_co; qemu_mutex_lock(&thr->mutex); From 90ddc64fb2b9b1d698efc6d76026e76d5fe224ce Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:44 +0300 Subject: [PATCH 16/34] block/nbd: rename NBDConnectThread to NBDClientConnection We are going to move the connection code to its own file, and want clear names and APIs first. The structure is shared between user and (possibly) several runs of connect-thread. So it's wrong to call it "thread". Let's rename to something more generic. Appropriately rename connect_thread and thr variables to conn. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Roman Kagan Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-15-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 134 ++++++++++++++++++++++++++-------------------------- 1 file changed, 67 insertions(+), 67 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index bee615e5c4..ce8d38d17a 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -66,7 +66,7 @@ typedef enum NBDClientState { NBD_CLIENT_QUIT } NBDClientState; -typedef struct NBDConnectThread { +typedef struct NBDClientConnection { /* Initialization constants */ SocketAddress *saddr; /* address to connect to */ @@ -91,7 +91,7 @@ typedef struct NBDConnectThread { * nbd_co_establish_connection() after yield() */ Coroutine *wait_co; -} NBDConnectThread; +} NBDClientConnection; typedef struct BDRVNBDState { QIOChannelSocket *sioc; /* The master data channel */ @@ -124,36 +124,36 @@ typedef struct BDRVNBDState { char *x_dirty_bitmap; bool alloc_depth; - NBDConnectThread *connect_thread; + NBDClientConnection *conn; } BDRVNBDState; -static void nbd_free_connect_thread(NBDConnectThread *thr); +static void nbd_free_connect_thread(NBDClientConnection *conn); static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr, Error **errp); static coroutine_fn QIOChannelSocket * -nbd_co_establish_connection(NBDConnectThread *thr, Error **errp); -static void nbd_co_establish_connection_cancel(NBDConnectThread *thr); +nbd_co_establish_connection(NBDClientConnection *conn, Error **errp); +static void nbd_co_establish_connection_cancel(NBDClientConnection *conn); static int nbd_client_handshake(BlockDriverState *bs, Error **errp); static void nbd_yank(void *opaque); static void nbd_clear_bdrvstate(BlockDriverState *bs) { BDRVNBDState *s = (BDRVNBDState *)bs->opaque; - NBDConnectThread *thr = s->connect_thread; + NBDClientConnection *conn = s->conn; bool do_free = false; - qemu_mutex_lock(&thr->mutex); - assert(!thr->detached); - if (thr->running) { - thr->detached = true; + qemu_mutex_lock(&conn->mutex); + assert(!conn->detached); + if (conn->running) { + conn->detached = true; } else { do_free = true; } - qemu_mutex_unlock(&thr->mutex); + qemu_mutex_unlock(&conn->mutex); /* the runaway thread will clean up itself */ if (do_free) { - nbd_free_connect_thread(thr); + nbd_free_connect_thread(conn); } yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name)); @@ -295,7 +295,7 @@ static void coroutine_fn nbd_client_co_drain_begin(BlockDriverState *bs) s->drained = true; qemu_co_sleep_wake(&s->reconnect_sleep); - nbd_co_establish_connection_cancel(s->connect_thread); + nbd_co_establish_connection_cancel(s->conn); reconnect_delay_timer_del(s); @@ -333,7 +333,7 @@ static void nbd_teardown_connection(BlockDriverState *bs) s->state = NBD_CLIENT_QUIT; if (s->connection_co) { qemu_co_sleep_wake(&s->reconnect_sleep); - nbd_co_establish_connection_cancel(s->connect_thread); + nbd_co_establish_connection_cancel(s->conn); } if (qemu_in_coroutine()) { s->teardown_co = qemu_coroutine_self(); @@ -360,65 +360,65 @@ static bool nbd_client_connecting_wait(BDRVNBDState *s) static void nbd_init_connect_thread(BDRVNBDState *s) { - s->connect_thread = g_new(NBDConnectThread, 1); + s->conn = g_new(NBDClientConnection, 1); - *s->connect_thread = (NBDConnectThread) { + *s->conn = (NBDClientConnection) { .saddr = QAPI_CLONE(SocketAddress, s->saddr), }; - qemu_mutex_init(&s->connect_thread->mutex); + qemu_mutex_init(&s->conn->mutex); } -static void nbd_free_connect_thread(NBDConnectThread *thr) +static void nbd_free_connect_thread(NBDClientConnection *conn) { - if (thr->sioc) { - qio_channel_close(QIO_CHANNEL(thr->sioc), NULL); - object_unref(OBJECT(thr->sioc)); + if (conn->sioc) { + qio_channel_close(QIO_CHANNEL(conn->sioc), NULL); + object_unref(OBJECT(conn->sioc)); } - error_free(thr->err); - qapi_free_SocketAddress(thr->saddr); - g_free(thr); + error_free(conn->err); + qapi_free_SocketAddress(conn->saddr); + g_free(conn); } static void *connect_thread_func(void *opaque) { - NBDConnectThread *thr = opaque; + NBDClientConnection *conn = opaque; int ret; bool do_free; - thr->sioc = qio_channel_socket_new(); + conn->sioc = qio_channel_socket_new(); - error_free(thr->err); - thr->err = NULL; - ret = qio_channel_socket_connect_sync(thr->sioc, thr->saddr, &thr->err); + error_free(conn->err); + conn->err = NULL; + ret = qio_channel_socket_connect_sync(conn->sioc, conn->saddr, &conn->err); if (ret < 0) { - object_unref(OBJECT(thr->sioc)); - thr->sioc = NULL; + object_unref(OBJECT(conn->sioc)); + conn->sioc = NULL; } - qio_channel_set_delay(QIO_CHANNEL(thr->sioc), false); + qio_channel_set_delay(QIO_CHANNEL(conn->sioc), false); - qemu_mutex_lock(&thr->mutex); + qemu_mutex_lock(&conn->mutex); - assert(thr->running); - thr->running = false; - if (thr->wait_co) { - aio_co_wake(thr->wait_co); - thr->wait_co = NULL; + assert(conn->running); + conn->running = false; + if (conn->wait_co) { + aio_co_wake(conn->wait_co); + conn->wait_co = NULL; } - do_free = thr->detached; + do_free = conn->detached; - qemu_mutex_unlock(&thr->mutex); + qemu_mutex_unlock(&conn->mutex); if (do_free) { - nbd_free_connect_thread(thr); + nbd_free_connect_thread(conn); } return NULL; } /* - * Get a new connection in context of @thr: + * Get a new connection in context of @conn: * if the thread is running, wait for completion * if the thread already succeeded in the background, and user didn't get the * result, just return it now @@ -426,38 +426,38 @@ static void *connect_thread_func(void *opaque) * completion */ static coroutine_fn QIOChannelSocket * -nbd_co_establish_connection(NBDConnectThread *thr, Error **errp) +nbd_co_establish_connection(NBDClientConnection *conn, Error **errp) { QIOChannelSocket *sioc = NULL; QemuThread thread; - qemu_mutex_lock(&thr->mutex); + qemu_mutex_lock(&conn->mutex); /* * Don't call nbd_co_establish_connection() in several coroutines in * parallel. Only one call at once is supported. */ - assert(!thr->wait_co); + assert(!conn->wait_co); - if (!thr->running) { - if (thr->sioc) { + if (!conn->running) { + if (conn->sioc) { /* Previous attempt finally succeeded in background */ - sioc = g_steal_pointer(&thr->sioc); - qemu_mutex_unlock(&thr->mutex); + sioc = g_steal_pointer(&conn->sioc); + qemu_mutex_unlock(&conn->mutex); return sioc; } - thr->running = true; - error_free(thr->err); - thr->err = NULL; + conn->running = true; + error_free(conn->err); + conn->err = NULL; qemu_thread_create(&thread, "nbd-connect", - connect_thread_func, thr, QEMU_THREAD_DETACHED); + connect_thread_func, conn, QEMU_THREAD_DETACHED); } - thr->wait_co = qemu_coroutine_self(); + conn->wait_co = qemu_coroutine_self(); - qemu_mutex_unlock(&thr->mutex); + qemu_mutex_unlock(&conn->mutex); /* * We are going to wait for connect-thread finish, but @@ -465,9 +465,9 @@ nbd_co_establish_connection(NBDConnectThread *thr, Error **errp) */ qemu_coroutine_yield(); - qemu_mutex_lock(&thr->mutex); + qemu_mutex_lock(&conn->mutex); - if (thr->running) { + if (conn->running) { /* * The connection attempt was canceled and the coroutine resumed * before the connection thread finished its job. Report the @@ -476,12 +476,12 @@ nbd_co_establish_connection(NBDConnectThread *thr, Error **errp) */ error_setg(errp, "Connection attempt cancelled by other operation"); } else { - error_propagate(errp, thr->err); - thr->err = NULL; - sioc = g_steal_pointer(&thr->sioc); + error_propagate(errp, conn->err); + conn->err = NULL; + sioc = g_steal_pointer(&conn->sioc); } - qemu_mutex_unlock(&thr->mutex); + qemu_mutex_unlock(&conn->mutex); return sioc; } @@ -494,15 +494,15 @@ nbd_co_establish_connection(NBDConnectThread *thr, Error **errp) * socket, but rather safely wakes nbd_co_establish_connection() which is * sleeping in yield() */ -static void nbd_co_establish_connection_cancel(NBDConnectThread *thr) +static void nbd_co_establish_connection_cancel(NBDClientConnection *conn) { Coroutine *wait_co; - qemu_mutex_lock(&thr->mutex); + qemu_mutex_lock(&conn->mutex); - wait_co = g_steal_pointer(&thr->wait_co); + wait_co = g_steal_pointer(&conn->wait_co); - qemu_mutex_unlock(&thr->mutex); + qemu_mutex_unlock(&conn->mutex); if (wait_co) { aio_co_wake(wait_co); @@ -552,7 +552,7 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) s->ioc = NULL; } - s->sioc = nbd_co_establish_connection(s->connect_thread, NULL); + s->sioc = nbd_co_establish_connection(s->conn, NULL); if (!s->sioc) { ret = -ECONNREFUSED; goto out; From f68729747da6b770e895fa88fedf7997666bc735 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:45 +0300 Subject: [PATCH 17/34] block/nbd: introduce nbd_client_connection_new() This is a step of creating bs-independent nbd connection interface. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Roman Kagan Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-16-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index ce8d38d17a..e7261aeaef 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -358,15 +358,18 @@ static bool nbd_client_connecting_wait(BDRVNBDState *s) return qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTING_WAIT; } -static void nbd_init_connect_thread(BDRVNBDState *s) +static NBDClientConnection * +nbd_client_connection_new(const SocketAddress *saddr) { - s->conn = g_new(NBDClientConnection, 1); + NBDClientConnection *conn = g_new(NBDClientConnection, 1); - *s->conn = (NBDClientConnection) { - .saddr = QAPI_CLONE(SocketAddress, s->saddr), + *conn = (NBDClientConnection) { + .saddr = QAPI_CLONE(SocketAddress, saddr), }; - qemu_mutex_init(&s->conn->mutex); + qemu_mutex_init(&conn->mutex); + + return conn; } static void nbd_free_connect_thread(NBDClientConnection *conn) @@ -2230,7 +2233,7 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } - nbd_init_connect_thread(s); + s->conn = nbd_client_connection_new(s->saddr); /* * establish TCP connection, return error if it fails From 248d4701989dbe8de1c06aa8f65ef38f289df87b Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:46 +0300 Subject: [PATCH 18/34] block/nbd: introduce nbd_client_connection_release() This is a last step of creating bs-independent nbd connection interface. With next commit we can finally move it to separate file. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-17-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- block/nbd.c | 45 +++++++++++++++++++++++++++------------------ 1 file changed, 27 insertions(+), 18 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index e7261aeaef..fa6e5e85bd 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -127,7 +127,7 @@ typedef struct BDRVNBDState { NBDClientConnection *conn; } BDRVNBDState; -static void nbd_free_connect_thread(NBDClientConnection *conn); +static void nbd_client_connection_release(NBDClientConnection *conn); static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr, Error **errp); static coroutine_fn QIOChannelSocket * @@ -139,22 +139,9 @@ static void nbd_yank(void *opaque); static void nbd_clear_bdrvstate(BlockDriverState *bs) { BDRVNBDState *s = (BDRVNBDState *)bs->opaque; - NBDClientConnection *conn = s->conn; - bool do_free = false; - qemu_mutex_lock(&conn->mutex); - assert(!conn->detached); - if (conn->running) { - conn->detached = true; - } else { - do_free = true; - } - qemu_mutex_unlock(&conn->mutex); - - /* the runaway thread will clean up itself */ - if (do_free) { - nbd_free_connect_thread(conn); - } + nbd_client_connection_release(s->conn); + s->conn = NULL; yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name)); @@ -372,7 +359,7 @@ nbd_client_connection_new(const SocketAddress *saddr) return conn; } -static void nbd_free_connect_thread(NBDClientConnection *conn) +static void nbd_client_connection_do_free(NBDClientConnection *conn) { if (conn->sioc) { qio_channel_close(QIO_CHANNEL(conn->sioc), NULL); @@ -414,12 +401,34 @@ static void *connect_thread_func(void *opaque) qemu_mutex_unlock(&conn->mutex); if (do_free) { - nbd_free_connect_thread(conn); + nbd_client_connection_do_free(conn); } return NULL; } +static void nbd_client_connection_release(NBDClientConnection *conn) +{ + bool do_free = false; + + if (!conn) { + return; + } + + qemu_mutex_lock(&conn->mutex); + assert(!conn->detached); + if (conn->running) { + conn->detached = true; + } else { + do_free = true; + } + qemu_mutex_unlock(&conn->mutex); + + if (do_free) { + nbd_client_connection_do_free(conn); + } +} + /* * Get a new connection in context of @conn: * if the thread is running, wait for completion From 5276c87c12f4c2a2db0bf343f6d3092816f0afc6 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Tue, 15 Jun 2021 14:07:05 -0500 Subject: [PATCH 19/34] nbd: move connection code from block/nbd to nbd/client-connection We now have bs-independent connection API, which consists of four functions: nbd_client_connection_new() nbd_client_connection_release() nbd_co_establish_connection() nbd_co_establish_connection_cancel() Move them to a separate file together with NBDClientConnection structure which becomes private to the new API. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-18-vsementsov@virtuozzo.com> [eblake: comment tweaks] Signed-off-by: Eric Blake --- block/nbd.c | 207 ----------------------------------- include/block/nbd.h | 11 ++ nbd/client-connection.c | 232 ++++++++++++++++++++++++++++++++++++++++ nbd/meson.build | 1 + 4 files changed, 244 insertions(+), 207 deletions(-) create mode 100644 nbd/client-connection.c diff --git a/block/nbd.c b/block/nbd.c index fa6e5e85bd..26914509f1 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -66,33 +66,6 @@ typedef enum NBDClientState { NBD_CLIENT_QUIT } NBDClientState; -typedef struct NBDClientConnection { - /* Initialization constants */ - SocketAddress *saddr; /* address to connect to */ - - QemuMutex mutex; - - /* - * @sioc and @err represent a connection attempt. While running - * is true, they are only used by the connection thread, and mutex - * locking is not needed. Once the thread finishes, - * nbd_co_establish_connection then steals these pointers while - * under the mutex. - */ - QIOChannelSocket *sioc; - Error *err; - - /* All further fields are accessed only under mutex */ - bool running; /* thread is running now */ - bool detached; /* thread is detached and should cleanup the state */ - - /* - * wait_co: if non-NULL, which coroutine to wake in - * nbd_co_establish_connection() after yield() - */ - Coroutine *wait_co; -} NBDClientConnection; - typedef struct BDRVNBDState { QIOChannelSocket *sioc; /* The master data channel */ QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ @@ -127,12 +100,8 @@ typedef struct BDRVNBDState { NBDClientConnection *conn; } BDRVNBDState; -static void nbd_client_connection_release(NBDClientConnection *conn); static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr, Error **errp); -static coroutine_fn QIOChannelSocket * -nbd_co_establish_connection(NBDClientConnection *conn, Error **errp); -static void nbd_co_establish_connection_cancel(NBDClientConnection *conn); static int nbd_client_handshake(BlockDriverState *bs, Error **errp); static void nbd_yank(void *opaque); @@ -345,182 +314,6 @@ static bool nbd_client_connecting_wait(BDRVNBDState *s) return qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTING_WAIT; } -static NBDClientConnection * -nbd_client_connection_new(const SocketAddress *saddr) -{ - NBDClientConnection *conn = g_new(NBDClientConnection, 1); - - *conn = (NBDClientConnection) { - .saddr = QAPI_CLONE(SocketAddress, saddr), - }; - - qemu_mutex_init(&conn->mutex); - - return conn; -} - -static void nbd_client_connection_do_free(NBDClientConnection *conn) -{ - if (conn->sioc) { - qio_channel_close(QIO_CHANNEL(conn->sioc), NULL); - object_unref(OBJECT(conn->sioc)); - } - error_free(conn->err); - qapi_free_SocketAddress(conn->saddr); - g_free(conn); -} - -static void *connect_thread_func(void *opaque) -{ - NBDClientConnection *conn = opaque; - int ret; - bool do_free; - - conn->sioc = qio_channel_socket_new(); - - error_free(conn->err); - conn->err = NULL; - ret = qio_channel_socket_connect_sync(conn->sioc, conn->saddr, &conn->err); - if (ret < 0) { - object_unref(OBJECT(conn->sioc)); - conn->sioc = NULL; - } - - qio_channel_set_delay(QIO_CHANNEL(conn->sioc), false); - - qemu_mutex_lock(&conn->mutex); - - assert(conn->running); - conn->running = false; - if (conn->wait_co) { - aio_co_wake(conn->wait_co); - conn->wait_co = NULL; - } - do_free = conn->detached; - - qemu_mutex_unlock(&conn->mutex); - - if (do_free) { - nbd_client_connection_do_free(conn); - } - - return NULL; -} - -static void nbd_client_connection_release(NBDClientConnection *conn) -{ - bool do_free = false; - - if (!conn) { - return; - } - - qemu_mutex_lock(&conn->mutex); - assert(!conn->detached); - if (conn->running) { - conn->detached = true; - } else { - do_free = true; - } - qemu_mutex_unlock(&conn->mutex); - - if (do_free) { - nbd_client_connection_do_free(conn); - } -} - -/* - * Get a new connection in context of @conn: - * if the thread is running, wait for completion - * if the thread already succeeded in the background, and user didn't get the - * result, just return it now - * otherwise the thread is not running, so start a thread and wait for - * completion - */ -static coroutine_fn QIOChannelSocket * -nbd_co_establish_connection(NBDClientConnection *conn, Error **errp) -{ - QIOChannelSocket *sioc = NULL; - QemuThread thread; - - qemu_mutex_lock(&conn->mutex); - - /* - * Don't call nbd_co_establish_connection() in several coroutines in - * parallel. Only one call at once is supported. - */ - assert(!conn->wait_co); - - if (!conn->running) { - if (conn->sioc) { - /* Previous attempt finally succeeded in background */ - sioc = g_steal_pointer(&conn->sioc); - qemu_mutex_unlock(&conn->mutex); - - return sioc; - } - - conn->running = true; - error_free(conn->err); - conn->err = NULL; - qemu_thread_create(&thread, "nbd-connect", - connect_thread_func, conn, QEMU_THREAD_DETACHED); - } - - conn->wait_co = qemu_coroutine_self(); - - qemu_mutex_unlock(&conn->mutex); - - /* - * We are going to wait for connect-thread finish, but - * nbd_co_establish_connection_cancel() can interrupt. - */ - qemu_coroutine_yield(); - - qemu_mutex_lock(&conn->mutex); - - if (conn->running) { - /* - * The connection attempt was canceled and the coroutine resumed - * before the connection thread finished its job. Report the - * attempt as failed, but leave the connection thread running, - * to reuse it for the next connection attempt. - */ - error_setg(errp, "Connection attempt cancelled by other operation"); - } else { - error_propagate(errp, conn->err); - conn->err = NULL; - sioc = g_steal_pointer(&conn->sioc); - } - - qemu_mutex_unlock(&conn->mutex); - - return sioc; -} - -/* - * nbd_co_establish_connection_cancel - * Cancel nbd_co_establish_connection() asynchronously. - * - * Note that this function neither directly stops the thread nor closes the - * socket, but rather safely wakes nbd_co_establish_connection() which is - * sleeping in yield() - */ -static void nbd_co_establish_connection_cancel(NBDClientConnection *conn) -{ - Coroutine *wait_co; - - qemu_mutex_lock(&conn->mutex); - - wait_co = g_steal_pointer(&conn->wait_co); - - qemu_mutex_unlock(&conn->mutex); - - if (wait_co) { - aio_co_wake(wait_co); - } -} - static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) { int ret; diff --git a/include/block/nbd.h b/include/block/nbd.h index 5f34d23bb0..57381be76f 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -406,4 +406,15 @@ const char *nbd_info_lookup(uint16_t info); const char *nbd_cmd_lookup(uint16_t info); const char *nbd_err_lookup(int err); +/* nbd/client-connection.c */ +typedef struct NBDClientConnection NBDClientConnection; + +NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr); +void nbd_client_connection_release(NBDClientConnection *conn); + +QIOChannelSocket *coroutine_fn +nbd_co_establish_connection(NBDClientConnection *conn, Error **errp); + +void coroutine_fn nbd_co_establish_connection_cancel(NBDClientConnection *conn); + #endif diff --git a/nbd/client-connection.c b/nbd/client-connection.c new file mode 100644 index 0000000000..f3b270d38c --- /dev/null +++ b/nbd/client-connection.c @@ -0,0 +1,232 @@ +/* + * QEMU Block driver for NBD + * + * Copyright (c) 2021 Virtuozzo International GmbH. + * + * 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/nbd.h" + +#include "qapi/qapi-visit-sockets.h" +#include "qapi/clone-visitor.h" + +struct NBDClientConnection { + /* Initialization constants */ + SocketAddress *saddr; /* address to connect to */ + + QemuMutex mutex; + + /* + * @sioc and @err represent a connection attempt. While running + * is true, they are only used by the connection thread, and mutex + * locking is not needed. Once the thread finishes, + * nbd_co_establish_connection then steals these pointers while + * under the mutex. + */ + QIOChannelSocket *sioc; + Error *err; + + /* All further fields are accessed only under mutex */ + bool running; /* thread is running now */ + bool detached; /* thread is detached and should cleanup the state */ + + /* + * wait_co: if non-NULL, which coroutine to wake in + * nbd_co_establish_connection() after yield() + */ + Coroutine *wait_co; +}; + +NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr) +{ + NBDClientConnection *conn = g_new(NBDClientConnection, 1); + + *conn = (NBDClientConnection) { + .saddr = QAPI_CLONE(SocketAddress, saddr), + }; + + qemu_mutex_init(&conn->mutex); + + return conn; +} + +static void nbd_client_connection_do_free(NBDClientConnection *conn) +{ + if (conn->sioc) { + qio_channel_close(QIO_CHANNEL(conn->sioc), NULL); + object_unref(OBJECT(conn->sioc)); + } + error_free(conn->err); + qapi_free_SocketAddress(conn->saddr); + g_free(conn); +} + +static void *connect_thread_func(void *opaque) +{ + NBDClientConnection *conn = opaque; + int ret; + bool do_free; + + conn->sioc = qio_channel_socket_new(); + + error_free(conn->err); + conn->err = NULL; + ret = qio_channel_socket_connect_sync(conn->sioc, conn->saddr, &conn->err); + if (ret < 0) { + object_unref(OBJECT(conn->sioc)); + conn->sioc = NULL; + } + + qio_channel_set_delay(QIO_CHANNEL(conn->sioc), false); + + qemu_mutex_lock(&conn->mutex); + + assert(conn->running); + conn->running = false; + if (conn->wait_co) { + aio_co_wake(conn->wait_co); + conn->wait_co = NULL; + } + do_free = conn->detached; + + qemu_mutex_unlock(&conn->mutex); + + if (do_free) { + nbd_client_connection_do_free(conn); + } + + return NULL; +} + +void nbd_client_connection_release(NBDClientConnection *conn) +{ + bool do_free = false; + + if (!conn) { + return; + } + + qemu_mutex_lock(&conn->mutex); + assert(!conn->detached); + if (conn->running) { + conn->detached = true; + } else { + do_free = true; + } + qemu_mutex_unlock(&conn->mutex); + + if (do_free) { + nbd_client_connection_do_free(conn); + } +} + +/* + * Get a new connection in context of @conn: + * if the thread is running, wait for completion + * if the thread already succeeded in the background, and user didn't get the + * result, just return it now + * otherwise the thread is not running, so start a thread and wait for + * completion + */ +QIOChannelSocket *coroutine_fn +nbd_co_establish_connection(NBDClientConnection *conn, Error **errp) +{ + QIOChannelSocket *sioc = NULL; + QemuThread thread; + + qemu_mutex_lock(&conn->mutex); + + /* + * Don't call nbd_co_establish_connection() in several coroutines in + * parallel. Only one call at once is supported. + */ + assert(!conn->wait_co); + + if (!conn->running) { + if (conn->sioc) { + /* Previous attempt finally succeeded in background */ + sioc = g_steal_pointer(&conn->sioc); + qemu_mutex_unlock(&conn->mutex); + + return sioc; + } + + conn->running = true; + error_free(conn->err); + conn->err = NULL; + qemu_thread_create(&thread, "nbd-connect", + connect_thread_func, conn, QEMU_THREAD_DETACHED); + } + + conn->wait_co = qemu_coroutine_self(); + + qemu_mutex_unlock(&conn->mutex); + + /* + * We are going to wait for connect-thread finish, but + * nbd_co_establish_connection_cancel() can interrupt. + */ + qemu_coroutine_yield(); + + qemu_mutex_lock(&conn->mutex); + + if (conn->running) { + /* + * The connection attempt was canceled and the coroutine resumed + * before the connection thread finished its job. Report the + * attempt as failed, but leave the connection thread running, + * to reuse it for the next connection attempt. + */ + error_setg(errp, "Connection attempt cancelled by other operation"); + } else { + error_propagate(errp, conn->err); + conn->err = NULL; + sioc = g_steal_pointer(&conn->sioc); + } + + qemu_mutex_unlock(&conn->mutex); + + return sioc; +} + +/* + * nbd_co_establish_connection_cancel + * Cancel nbd_co_establish_connection() asynchronously. + * + * Note that this function neither directly stops the thread nor closes the + * socket, but rather safely wakes nbd_co_establish_connection() which is + * sleeping in yield() + */ +void nbd_co_establish_connection_cancel(NBDClientConnection *conn) +{ + Coroutine *wait_co; + + qemu_mutex_lock(&conn->mutex); + + wait_co = g_steal_pointer(&conn->wait_co); + + qemu_mutex_unlock(&conn->mutex); + + if (wait_co) { + aio_co_wake(wait_co); + } +} diff --git a/nbd/meson.build b/nbd/meson.build index 2baaa36948..b26d70565e 100644 --- a/nbd/meson.build +++ b/nbd/meson.build @@ -1,5 +1,6 @@ block_ss.add(files( 'client.c', + 'client-connection.c', 'common.c', )) blockdev_ss.add(files( From e70da5ff6445bf09db55e4828c08c2a30d816137 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:48 +0300 Subject: [PATCH 20/34] nbd/client-connection: use QEMU_LOCK_GUARD We don't update connect_thread_func() to use QEMU_LOCK_GUARD, as it will get more complex critical sections logic in further commit, where QEMU_LOCK_GUARD doesn't help. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-19-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- nbd/client-connection.c | 95 +++++++++++++++++++---------------------- 1 file changed, 43 insertions(+), 52 deletions(-) diff --git a/nbd/client-connection.c b/nbd/client-connection.c index f3b270d38c..eb5cae2eae 100644 --- a/nbd/client-connection.c +++ b/nbd/client-connection.c @@ -125,14 +125,14 @@ void nbd_client_connection_release(NBDClientConnection *conn) return; } - qemu_mutex_lock(&conn->mutex); - assert(!conn->detached); - if (conn->running) { - conn->detached = true; - } else { - do_free = true; + WITH_QEMU_LOCK_GUARD(&conn->mutex) { + assert(!conn->detached); + if (conn->running) { + conn->detached = true; + } else { + do_free = true; + } } - qemu_mutex_unlock(&conn->mutex); if (do_free) { nbd_client_connection_do_free(conn); @@ -150,62 +150,55 @@ void nbd_client_connection_release(NBDClientConnection *conn) QIOChannelSocket *coroutine_fn nbd_co_establish_connection(NBDClientConnection *conn, Error **errp) { - QIOChannelSocket *sioc = NULL; QemuThread thread; - qemu_mutex_lock(&conn->mutex); + WITH_QEMU_LOCK_GUARD(&conn->mutex) { + /* + * Don't call nbd_co_establish_connection() in several coroutines in + * parallel. Only one call at once is supported. + */ + assert(!conn->wait_co); - /* - * Don't call nbd_co_establish_connection() in several coroutines in - * parallel. Only one call at once is supported. - */ - assert(!conn->wait_co); + if (!conn->running) { + if (conn->sioc) { + /* Previous attempt finally succeeded in background */ + return g_steal_pointer(&conn->sioc); + } - if (!conn->running) { - if (conn->sioc) { - /* Previous attempt finally succeeded in background */ - sioc = g_steal_pointer(&conn->sioc); - qemu_mutex_unlock(&conn->mutex); - - return sioc; + conn->running = true; + error_free(conn->err); + conn->err = NULL; + qemu_thread_create(&thread, "nbd-connect", + connect_thread_func, conn, QEMU_THREAD_DETACHED); } - conn->running = true; - error_free(conn->err); - conn->err = NULL; - qemu_thread_create(&thread, "nbd-connect", - connect_thread_func, conn, QEMU_THREAD_DETACHED); + conn->wait_co = qemu_coroutine_self(); } - conn->wait_co = qemu_coroutine_self(); - - qemu_mutex_unlock(&conn->mutex); - /* * We are going to wait for connect-thread finish, but * nbd_co_establish_connection_cancel() can interrupt. */ qemu_coroutine_yield(); - qemu_mutex_lock(&conn->mutex); - - if (conn->running) { - /* - * The connection attempt was canceled and the coroutine resumed - * before the connection thread finished its job. Report the - * attempt as failed, but leave the connection thread running, - * to reuse it for the next connection attempt. - */ - error_setg(errp, "Connection attempt cancelled by other operation"); - } else { - error_propagate(errp, conn->err); - conn->err = NULL; - sioc = g_steal_pointer(&conn->sioc); + WITH_QEMU_LOCK_GUARD(&conn->mutex) { + if (conn->running) { + /* + * The connection attempt was canceled and the coroutine resumed + * before the connection thread finished its job. Report the + * attempt as failed, but leave the connection thread running, + * to reuse it for the next connection attempt. + */ + error_setg(errp, "Connection attempt cancelled by other operation"); + return NULL; + } else { + error_propagate(errp, conn->err); + conn->err = NULL; + return g_steal_pointer(&conn->sioc); + } } - qemu_mutex_unlock(&conn->mutex); - - return sioc; + abort(); /* unreachable */ } /* @@ -220,11 +213,9 @@ void nbd_co_establish_connection_cancel(NBDClientConnection *conn) { Coroutine *wait_co; - qemu_mutex_lock(&conn->mutex); - - wait_co = g_steal_pointer(&conn->wait_co); - - qemu_mutex_unlock(&conn->mutex); + WITH_QEMU_LOCK_GUARD(&conn->mutex) { + wait_co = g_steal_pointer(&conn->wait_co); + } if (wait_co) { aio_co_wake(wait_co); From 130d49baa50655729f09efb72e77bebf09421dd7 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:49 +0300 Subject: [PATCH 21/34] nbd/client-connection: add possibility of negotiation Add arguments and logic to support nbd negotiation in the same thread after successful connection. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-20-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- block/nbd.c | 4 +- include/block/nbd.h | 9 +++- nbd/client-connection.c | 105 ++++++++++++++++++++++++++++++++++++++-- 3 files changed, 109 insertions(+), 9 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 26914509f1..df9d241313 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -357,7 +357,7 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) s->ioc = NULL; } - s->sioc = nbd_co_establish_connection(s->conn, NULL); + s->sioc = nbd_co_establish_connection(s->conn, NULL, NULL, NULL); if (!s->sioc) { ret = -ECONNREFUSED; goto out; @@ -2035,7 +2035,7 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } - s->conn = nbd_client_connection_new(s->saddr); + s->conn = nbd_client_connection_new(s->saddr, false, NULL, NULL, NULL); /* * establish TCP connection, return error if it fails diff --git a/include/block/nbd.h b/include/block/nbd.h index 57381be76f..5d86e6a393 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -409,11 +409,16 @@ const char *nbd_err_lookup(int err); /* nbd/client-connection.c */ typedef struct NBDClientConnection NBDClientConnection; -NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr); +NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr, + bool do_negotiation, + const char *export_name, + const char *x_dirty_bitmap, + QCryptoTLSCreds *tlscreds); void nbd_client_connection_release(NBDClientConnection *conn); QIOChannelSocket *coroutine_fn -nbd_co_establish_connection(NBDClientConnection *conn, Error **errp); +nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info, + QIOChannel **ioc, Error **errp); void coroutine_fn nbd_co_establish_connection_cancel(NBDClientConnection *conn); diff --git a/nbd/client-connection.c b/nbd/client-connection.c index eb5cae2eae..4ed37cd73f 100644 --- a/nbd/client-connection.c +++ b/nbd/client-connection.c @@ -30,8 +30,11 @@ #include "qapi/clone-visitor.h" struct NBDClientConnection { - /* Initialization constants */ + /* Initialization constants, never change */ SocketAddress *saddr; /* address to connect to */ + QCryptoTLSCreds *tlscreds; + NBDExportInfo initial_info; + bool do_negotiation; QemuMutex mutex; @@ -42,7 +45,9 @@ struct NBDClientConnection { * nbd_co_establish_connection then steals these pointers while * under the mutex. */ + NBDExportInfo updated_info; QIOChannelSocket *sioc; + QIOChannel *ioc; Error *err; /* All further fields are accessed only under mutex */ @@ -56,12 +61,25 @@ struct NBDClientConnection { Coroutine *wait_co; }; -NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr) +NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr, + bool do_negotiation, + const char *export_name, + const char *x_dirty_bitmap, + QCryptoTLSCreds *tlscreds) { NBDClientConnection *conn = g_new(NBDClientConnection, 1); + object_ref(OBJECT(tlscreds)); *conn = (NBDClientConnection) { .saddr = QAPI_CLONE(SocketAddress, saddr), + .tlscreds = tlscreds, + .do_negotiation = do_negotiation, + + .initial_info.request_sizes = true, + .initial_info.structured_reply = true, + .initial_info.base_allocation = true, + .initial_info.x_dirty_bitmap = g_strdup(x_dirty_bitmap), + .initial_info.name = g_strdup(export_name ?: "") }; qemu_mutex_init(&conn->mutex); @@ -77,9 +95,61 @@ static void nbd_client_connection_do_free(NBDClientConnection *conn) } error_free(conn->err); qapi_free_SocketAddress(conn->saddr); + object_unref(OBJECT(conn->tlscreds)); + g_free(conn->initial_info.x_dirty_bitmap); + g_free(conn->initial_info.name); g_free(conn); } +/* + * Connect to @addr and do NBD negotiation if @info is not null. If @tlscreds + * are given @outioc is returned. @outioc is provided only on success. The call + * may be cancelled from other thread by simply qio_channel_shutdown(sioc). + */ +static int nbd_connect(QIOChannelSocket *sioc, SocketAddress *addr, + NBDExportInfo *info, QCryptoTLSCreds *tlscreds, + QIOChannel **outioc, Error **errp) +{ + int ret; + + if (outioc) { + *outioc = NULL; + } + + ret = qio_channel_socket_connect_sync(sioc, addr, errp); + if (ret < 0) { + return ret; + } + + qio_channel_set_delay(QIO_CHANNEL(sioc), false); + + if (!info) { + return 0; + } + + ret = nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc), tlscreds, + tlscreds ? addr->u.inet.host : NULL, + outioc, info, errp); + if (ret < 0) { + /* + * nbd_receive_negotiate() may setup tls ioc and return it even on + * failure path. In this case we should use it instead of original + * channel. + */ + if (outioc && *outioc) { + qio_channel_close(QIO_CHANNEL(*outioc), NULL); + object_unref(OBJECT(*outioc)); + *outioc = NULL; + } else { + qio_channel_close(QIO_CHANNEL(sioc), NULL); + } + + return ret; + } + + return 0; +} + static void *connect_thread_func(void *opaque) { NBDClientConnection *conn = opaque; @@ -90,13 +160,18 @@ static void *connect_thread_func(void *opaque) error_free(conn->err); conn->err = NULL; - ret = qio_channel_socket_connect_sync(conn->sioc, conn->saddr, &conn->err); + conn->updated_info = conn->initial_info; + + ret = nbd_connect(conn->sioc, conn->saddr, + conn->do_negotiation ? &conn->updated_info : NULL, + conn->tlscreds, &conn->ioc, &conn->err); if (ret < 0) { object_unref(OBJECT(conn->sioc)); conn->sioc = NULL; } - qio_channel_set_delay(QIO_CHANNEL(conn->sioc), false); + conn->updated_info.x_dirty_bitmap = NULL; + conn->updated_info.name = NULL; qemu_mutex_lock(&conn->mutex); @@ -146,12 +221,24 @@ void nbd_client_connection_release(NBDClientConnection *conn) * result, just return it now * otherwise the thread is not running, so start a thread and wait for * completion + * + * If @info is not NULL, also do nbd-negotiation after successful connection. + * In this case info is used only as out parameter, and is fully initialized by + * nbd_co_establish_connection(). "IN" fields of info as well as related only to + * nbd_receive_export_list() would be zero (see description of NBDExportInfo in + * include/block/nbd.h). */ QIOChannelSocket *coroutine_fn -nbd_co_establish_connection(NBDClientConnection *conn, Error **errp) +nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info, + QIOChannel **ioc, Error **errp) { QemuThread thread; + if (conn->do_negotiation) { + assert(info); + assert(ioc); + } + WITH_QEMU_LOCK_GUARD(&conn->mutex) { /* * Don't call nbd_co_establish_connection() in several coroutines in @@ -162,6 +249,10 @@ nbd_co_establish_connection(NBDClientConnection *conn, Error **errp) if (!conn->running) { if (conn->sioc) { /* Previous attempt finally succeeded in background */ + if (conn->do_negotiation) { + *ioc = g_steal_pointer(&conn->ioc); + memcpy(info, &conn->updated_info, sizeof(*info)); + } return g_steal_pointer(&conn->sioc); } @@ -194,6 +285,10 @@ nbd_co_establish_connection(NBDClientConnection *conn, Error **errp) } else { error_propagate(errp, conn->err); conn->err = NULL; + if (conn->sioc && conn->do_negotiation) { + *ioc = g_steal_pointer(&conn->ioc); + memcpy(info, &conn->updated_info, sizeof(*info)); + } return g_steal_pointer(&conn->sioc); } } From e0e67cbe58f42500e3451c46b3caba572f2a965f Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:50 +0300 Subject: [PATCH 22/34] nbd/client-connection: implement connection retry Add an option for a thread to retry connecting until it succeeds. We'll use nbd/client-connection both for reconnect and for initial connection in nbd_open(), so we need a possibility to use same NBDClientConnection instance to connect once in nbd_open() and then use retry semantics for reconnect. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-21-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake [eblake: grammar tweak] Signed-off-by: Eric Blake --- include/block/nbd.h | 2 ++ nbd/client-connection.c | 56 +++++++++++++++++++++++++++++++---------- 2 files changed, 45 insertions(+), 13 deletions(-) diff --git a/include/block/nbd.h b/include/block/nbd.h index 5d86e6a393..5bb54d831c 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -409,6 +409,8 @@ const char *nbd_err_lookup(int err); /* nbd/client-connection.c */ typedef struct NBDClientConnection NBDClientConnection; +void nbd_client_connection_enable_retry(NBDClientConnection *conn); + NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr, bool do_negotiation, const char *export_name, diff --git a/nbd/client-connection.c b/nbd/client-connection.c index 4ed37cd73f..032b38ed3e 100644 --- a/nbd/client-connection.c +++ b/nbd/client-connection.c @@ -35,6 +35,7 @@ struct NBDClientConnection { QCryptoTLSCreds *tlscreds; NBDExportInfo initial_info; bool do_negotiation; + bool do_retry; QemuMutex mutex; @@ -61,6 +62,15 @@ struct NBDClientConnection { Coroutine *wait_co; }; +/* + * The function isn't protected by any mutex, only call it when the client + * connection attempt has not yet started. + */ +void nbd_client_connection_enable_retry(NBDClientConnection *conn) +{ + conn->do_retry = true; +} + NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr, bool do_negotiation, const char *export_name, @@ -155,24 +165,44 @@ static void *connect_thread_func(void *opaque) NBDClientConnection *conn = opaque; int ret; bool do_free; + uint64_t timeout = 1; + uint64_t max_timeout = 16; - conn->sioc = qio_channel_socket_new(); + while (true) { + conn->sioc = qio_channel_socket_new(); - error_free(conn->err); - conn->err = NULL; - conn->updated_info = conn->initial_info; + error_free(conn->err); + conn->err = NULL; + conn->updated_info = conn->initial_info; - ret = nbd_connect(conn->sioc, conn->saddr, - conn->do_negotiation ? &conn->updated_info : NULL, - conn->tlscreds, &conn->ioc, &conn->err); - if (ret < 0) { - object_unref(OBJECT(conn->sioc)); - conn->sioc = NULL; + ret = nbd_connect(conn->sioc, conn->saddr, + conn->do_negotiation ? &conn->updated_info : NULL, + conn->tlscreds, &conn->ioc, &conn->err); + + /* + * conn->updated_info will finally be returned to the user. Clear the + * pointers to our internally allocated strings, which are IN parameters + * of nbd_receive_negotiate() and therefore nbd_connect(). Caller + * shoudn't be interested in these fields. + */ + conn->updated_info.x_dirty_bitmap = NULL; + conn->updated_info.name = NULL; + + if (ret < 0) { + object_unref(OBJECT(conn->sioc)); + conn->sioc = NULL; + if (conn->do_retry) { + sleep(timeout); + if (timeout < max_timeout) { + timeout *= 2; + } + continue; + } + } + + break; } - conn->updated_info.x_dirty_bitmap = NULL; - conn->updated_info.name = NULL; - qemu_mutex_lock(&conn->mutex); assert(conn->running); From f58b2dfe3e815d0c8491b33c36622824e8a08e40 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:51 +0300 Subject: [PATCH 23/34] nbd/client-connection: shutdown connection on release Now, when a thread can do negotiation and retry, it may run relatively long. We need a mechanism to stop it, when the user is not interested in a result any more. So, on nbd_client_connection_release() let's shutdown the socket, and do not retry connection if thread is detached. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-22-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- nbd/client-connection.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/nbd/client-connection.c b/nbd/client-connection.c index 032b38ed3e..883f9cf158 100644 --- a/nbd/client-connection.c +++ b/nbd/client-connection.c @@ -168,9 +168,13 @@ static void *connect_thread_func(void *opaque) uint64_t timeout = 1; uint64_t max_timeout = 16; - while (true) { + qemu_mutex_lock(&conn->mutex); + while (!conn->detached) { + assert(!conn->sioc); conn->sioc = qio_channel_socket_new(); + qemu_mutex_unlock(&conn->mutex); + error_free(conn->err); conn->err = NULL; conn->updated_info = conn->initial_info; @@ -188,14 +192,20 @@ static void *connect_thread_func(void *opaque) conn->updated_info.x_dirty_bitmap = NULL; conn->updated_info.name = NULL; + qemu_mutex_lock(&conn->mutex); + if (ret < 0) { object_unref(OBJECT(conn->sioc)); conn->sioc = NULL; - if (conn->do_retry) { + if (conn->do_retry && !conn->detached) { + qemu_mutex_unlock(&conn->mutex); + sleep(timeout); if (timeout < max_timeout) { timeout *= 2; } + + qemu_mutex_lock(&conn->mutex); continue; } } @@ -203,7 +213,7 @@ static void *connect_thread_func(void *opaque) break; } - qemu_mutex_lock(&conn->mutex); + /* mutex is locked */ assert(conn->running); conn->running = false; @@ -237,6 +247,10 @@ void nbd_client_connection_release(NBDClientConnection *conn) } else { do_free = true; } + if (conn->sioc) { + qio_channel_shutdown(QIO_CHANNEL(conn->sioc), + QIO_CHANNEL_SHUTDOWN_BOTH, NULL); + } } if (do_free) { From e9ba7788b0c4328f7123eccb60cbb68b0b62bacb Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:52 +0300 Subject: [PATCH 24/34] block/nbd: split nbd_handle_updated_info out of nbd_client_handshake() To be reused in the following patch. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Roman Kagan Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-23-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 100 ++++++++++++++++++++++++++++++---------------------- 1 file changed, 58 insertions(+), 42 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index df9d241313..240c6e1b3d 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -314,6 +314,51 @@ static bool nbd_client_connecting_wait(BDRVNBDState *s) return qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTING_WAIT; } +/* + * Update @bs with information learned during a completed negotiation process. + * Return failure if the server's advertised options are incompatible with the + * client's needs. + */ +static int nbd_handle_updated_info(BlockDriverState *bs, Error **errp) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + int ret; + + if (s->x_dirty_bitmap) { + if (!s->info.base_allocation) { + error_setg(errp, "requested x-dirty-bitmap %s not found", + s->x_dirty_bitmap); + return -EINVAL; + } + if (strcmp(s->x_dirty_bitmap, "qemu:allocation-depth") == 0) { + s->alloc_depth = true; + } + } + + if (s->info.flags & NBD_FLAG_READ_ONLY) { + ret = bdrv_apply_auto_read_only(bs, "NBD export is read-only", errp); + if (ret < 0) { + return ret; + } + } + + if (s->info.flags & NBD_FLAG_SEND_FUA) { + bs->supported_write_flags = BDRV_REQ_FUA; + bs->supported_zero_flags |= BDRV_REQ_FUA; + } + + if (s->info.flags & NBD_FLAG_SEND_WRITE_ZEROES) { + bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP; + if (s->info.flags & NBD_FLAG_SEND_FAST_ZERO) { + bs->supported_zero_flags |= BDRV_REQ_NO_FALLBACK; + } + } + + trace_nbd_client_handshake_success(s->export); + + return 0; +} + static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) { int ret; @@ -1575,49 +1620,13 @@ static int nbd_client_handshake(BlockDriverState *bs, Error **errp) s->sioc = NULL; return ret; } - if (s->x_dirty_bitmap) { - if (!s->info.base_allocation) { - error_setg(errp, "requested x-dirty-bitmap %s not found", - s->x_dirty_bitmap); - ret = -EINVAL; - goto fail; - } - if (strcmp(s->x_dirty_bitmap, "qemu:allocation-depth") == 0) { - s->alloc_depth = true; - } - } - if (s->info.flags & NBD_FLAG_READ_ONLY) { - ret = bdrv_apply_auto_read_only(bs, "NBD export is read-only", errp); - if (ret < 0) { - goto fail; - } - } - if (s->info.flags & NBD_FLAG_SEND_FUA) { - bs->supported_write_flags = BDRV_REQ_FUA; - bs->supported_zero_flags |= BDRV_REQ_FUA; - } - if (s->info.flags & NBD_FLAG_SEND_WRITE_ZEROES) { - bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP; - if (s->info.flags & NBD_FLAG_SEND_FAST_ZERO) { - bs->supported_zero_flags |= BDRV_REQ_NO_FALLBACK; - } - } - if (!s->ioc) { - s->ioc = QIO_CHANNEL(s->sioc); - object_ref(OBJECT(s->ioc)); - } - - trace_nbd_client_handshake_success(s->export); - - return 0; - - fail: - /* - * We have connected, but must fail for other reasons. - * Send NBD_CMD_DISC as a courtesy to the server. - */ - { + ret = nbd_handle_updated_info(bs, errp); + if (ret < 0) { + /* + * We have connected, but must fail for other reasons. + * Send NBD_CMD_DISC as a courtesy to the server. + */ NBDRequest request = { .type = NBD_CMD_DISC }; nbd_send_request(s->ioc ?: QIO_CHANNEL(s->sioc), &request); @@ -1631,6 +1640,13 @@ static int nbd_client_handshake(BlockDriverState *bs, Error **errp) return ret; } + + if (!s->ioc) { + s->ioc = QIO_CHANNEL(s->sioc); + object_ref(OBJECT(s->ioc)); + } + + return 0; } /* From 6d2b0332d3a2d85bb37786a914c6865a4386ef87 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:53 +0300 Subject: [PATCH 25/34] block/nbd: use negotiation of NBDClientConnection Now that we can opt in to negotiation as part of the client connection thread, use that to simplify connection_co. This is another step on the way to moving all reconnect code into NBDClientConnection. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-24-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 44 ++++++++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 14 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 240c6e1b3d..3114716444 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -362,6 +362,7 @@ static int nbd_handle_updated_info(BlockDriverState *bs, Error **errp) static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) { int ret; + AioContext *aio_context = bdrv_get_aio_context(s->bs); if (!nbd_client_connecting(s)) { return; @@ -402,30 +403,44 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) s->ioc = NULL; } - s->sioc = nbd_co_establish_connection(s->conn, NULL, NULL, NULL); + s->sioc = nbd_co_establish_connection(s->conn, &s->info, &s->ioc, NULL); if (!s->sioc) { ret = -ECONNREFUSED; goto out; } + qio_channel_set_blocking(QIO_CHANNEL(s->sioc), false, NULL); + qio_channel_attach_aio_context(QIO_CHANNEL(s->sioc), aio_context); + if (s->ioc) { + qio_channel_set_blocking(QIO_CHANNEL(s->ioc), false, NULL); + qio_channel_attach_aio_context(QIO_CHANNEL(s->ioc), aio_context); + } else { + s->ioc = QIO_CHANNEL(s->sioc); + object_ref(OBJECT(s->ioc)); + } + yank_register_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank, s->bs); - bdrv_dec_in_flight(s->bs); + ret = nbd_handle_updated_info(s->bs, NULL); + if (ret < 0) { + /* + * We have connected, but must fail for other reasons. + * Send NBD_CMD_DISC as a courtesy to the server. + */ + NBDRequest request = { .type = NBD_CMD_DISC }; - ret = nbd_client_handshake(s->bs, NULL); + nbd_send_request(s->ioc, &request); - if (s->drained) { - s->wait_drained_end = true; - while (s->drained) { - /* - * We may be entered once from nbd_client_attach_aio_context_bh - * and then from nbd_client_co_drain_end. So here is a loop. - */ - qemu_coroutine_yield(); - } + yank_unregister_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), + nbd_yank, s->bs); + object_unref(OBJECT(s->sioc)); + s->sioc = NULL; + object_unref(OBJECT(s->ioc)); + s->ioc = NULL; + + return; } - bdrv_inc_in_flight(s->bs); out: if (ret >= 0) { @@ -2051,7 +2066,8 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } - s->conn = nbd_client_connection_new(s->saddr, false, NULL, NULL, NULL); + s->conn = nbd_client_connection_new(s->saddr, true, s->export, + s->x_dirty_bitmap, s->tlscreds); /* * establish TCP connection, return error if it fails From c2405af0e418a3f4cca0840f31161f7ac17b9697 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:54 +0300 Subject: [PATCH 26/34] block/nbd: don't touch s->sioc in nbd_teardown_connection() Negotiation during reconnect is now done in a thread, and s->sioc is not available during negotiation. Negotiation in thread will be cancelled by nbd_client_connection_release() called from nbd_clear_bdrvstate(). So, we don't need this code chunk anymore. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-25-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 3114716444..2abcedd464 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -280,10 +280,6 @@ static void nbd_teardown_connection(BlockDriverState *bs) if (s->ioc) { /* finish any pending coroutines */ qio_channel_shutdown(s->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); - } else if (s->sioc) { - /* abort negotiation */ - qio_channel_shutdown(QIO_CHANNEL(s->sioc), QIO_CHANNEL_SHUTDOWN_BOTH, - NULL); } s->state = NBD_CLIENT_QUIT; From 95a078ea3e4863c0d516cf19ebcb5130bc760f49 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:55 +0300 Subject: [PATCH 27/34] block/nbd: drop BDRVNBDState::sioc Currently sioc pointer is used just to pass from socket-connection to nbd negotiation. Drop the field, and use local variables instead. With next commit we'll update nbd/client-connection.c to behave appropriately (return only top-most ioc, not two channels). Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-26-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 98 ++++++++++++++++++++++++++--------------------------- 1 file changed, 48 insertions(+), 50 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 2abcedd464..9f193d130b 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -67,8 +67,7 @@ typedef enum NBDClientState { } NBDClientState; typedef struct BDRVNBDState { - QIOChannelSocket *sioc; /* The master data channel */ - QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ + QIOChannel *ioc; /* The current I/O channel */ NBDExportInfo info; CoMutex send_mutex; @@ -100,9 +99,11 @@ typedef struct BDRVNBDState { NBDClientConnection *conn; } BDRVNBDState; -static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr, - Error **errp); -static int nbd_client_handshake(BlockDriverState *bs, Error **errp); +static QIOChannelSocket *nbd_establish_connection(BlockDriverState *bs, + SocketAddress *saddr, + Error **errp); +static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc, + Error **errp); static void nbd_yank(void *opaque); static void nbd_clear_bdrvstate(BlockDriverState *bs) @@ -359,6 +360,7 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) { int ret; AioContext *aio_context = bdrv_get_aio_context(s->bs); + QIOChannelSocket *sioc; if (!nbd_client_connecting(s)) { return; @@ -393,27 +395,26 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) qio_channel_detach_aio_context(QIO_CHANNEL(s->ioc)); yank_unregister_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank, s->bs); - object_unref(OBJECT(s->sioc)); - s->sioc = NULL; object_unref(OBJECT(s->ioc)); s->ioc = NULL; } - s->sioc = nbd_co_establish_connection(s->conn, &s->info, &s->ioc, NULL); - if (!s->sioc) { + sioc = nbd_co_establish_connection(s->conn, &s->info, &s->ioc, NULL); + if (!sioc) { ret = -ECONNREFUSED; goto out; } - qio_channel_set_blocking(QIO_CHANNEL(s->sioc), false, NULL); - qio_channel_attach_aio_context(QIO_CHANNEL(s->sioc), aio_context); if (s->ioc) { - qio_channel_set_blocking(QIO_CHANNEL(s->ioc), false, NULL); - qio_channel_attach_aio_context(QIO_CHANNEL(s->ioc), aio_context); + /* sioc is referenced by s->ioc */ + object_unref(OBJECT(sioc)); } else { - s->ioc = QIO_CHANNEL(s->sioc); - object_ref(OBJECT(s->ioc)); + s->ioc = QIO_CHANNEL(sioc); } + sioc = NULL; + + qio_channel_set_blocking(QIO_CHANNEL(s->ioc), false, NULL); + qio_channel_attach_aio_context(QIO_CHANNEL(s->ioc), aio_context); yank_register_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank, s->bs); @@ -430,8 +431,6 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) yank_unregister_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank, s->bs); - object_unref(OBJECT(s->sioc)); - s->sioc = NULL; object_unref(OBJECT(s->ioc)); s->ioc = NULL; @@ -566,8 +565,6 @@ static coroutine_fn void nbd_connection_entry(void *opaque) qio_channel_detach_aio_context(QIO_CHANNEL(s->ioc)); yank_unregister_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank, s->bs); - object_unref(OBJECT(s->sioc)); - s->sioc = NULL; object_unref(OBJECT(s->ioc)); s->ioc = NULL; } @@ -1566,7 +1563,7 @@ static void nbd_yank(void *opaque) BDRVNBDState *s = (BDRVNBDState *)bs->opaque; qatomic_store_release(&s->state, NBD_CLIENT_QUIT); - qio_channel_shutdown(QIO_CHANNEL(s->sioc), QIO_CHANNEL_SHUTDOWN_BOTH, NULL); + qio_channel_shutdown(QIO_CHANNEL(s->ioc), QIO_CHANNEL_SHUTDOWN_BOTH, NULL); } static void nbd_client_close(BlockDriverState *bs) @@ -1581,57 +1578,64 @@ static void nbd_client_close(BlockDriverState *bs) nbd_teardown_connection(bs); } -static int nbd_establish_connection(BlockDriverState *bs, - SocketAddress *saddr, - Error **errp) +static QIOChannelSocket *nbd_establish_connection(BlockDriverState *bs, + SocketAddress *saddr, + Error **errp) { ERRP_GUARD(); - BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + QIOChannelSocket *sioc; - s->sioc = qio_channel_socket_new(); - qio_channel_set_name(QIO_CHANNEL(s->sioc), "nbd-client"); + sioc = qio_channel_socket_new(); + qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client"); - qio_channel_socket_connect_sync(s->sioc, saddr, errp); + qio_channel_socket_connect_sync(sioc, saddr, errp); if (*errp) { - object_unref(OBJECT(s->sioc)); - s->sioc = NULL; - return -1; + object_unref(OBJECT(sioc)); + return NULL; } yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), nbd_yank, bs); - qio_channel_set_delay(QIO_CHANNEL(s->sioc), false); + qio_channel_set_delay(QIO_CHANNEL(sioc), false); - return 0; + return sioc; } -/* nbd_client_handshake takes ownership on s->sioc. On failure it's unref'ed. */ -static int nbd_client_handshake(BlockDriverState *bs, Error **errp) +/* nbd_client_handshake takes ownership on sioc. */ +static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc, + Error **errp) { BDRVNBDState *s = (BDRVNBDState *)bs->opaque; AioContext *aio_context = bdrv_get_aio_context(bs); int ret; trace_nbd_client_handshake(s->export); - qio_channel_set_blocking(QIO_CHANNEL(s->sioc), false, NULL); - qio_channel_attach_aio_context(QIO_CHANNEL(s->sioc), aio_context); + qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL); + qio_channel_attach_aio_context(QIO_CHANNEL(sioc), aio_context); s->info.request_sizes = true; s->info.structured_reply = true; s->info.base_allocation = true; s->info.x_dirty_bitmap = g_strdup(s->x_dirty_bitmap); s->info.name = g_strdup(s->export ?: ""); - ret = nbd_receive_negotiate(aio_context, QIO_CHANNEL(s->sioc), s->tlscreds, + ret = nbd_receive_negotiate(aio_context, QIO_CHANNEL(sioc), s->tlscreds, s->hostname, &s->ioc, &s->info, errp); g_free(s->info.x_dirty_bitmap); g_free(s->info.name); if (ret < 0) { yank_unregister_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), nbd_yank, bs); - object_unref(OBJECT(s->sioc)); - s->sioc = NULL; + object_unref(OBJECT(sioc)); return ret; } + if (s->ioc) { + /* sioc is referenced by s->ioc */ + object_unref(OBJECT(sioc)); + } else { + s->ioc = QIO_CHANNEL(sioc); + } + sioc = NULL; + ret = nbd_handle_updated_info(bs, errp); if (ret < 0) { /* @@ -1640,23 +1644,15 @@ static int nbd_client_handshake(BlockDriverState *bs, Error **errp) */ NBDRequest request = { .type = NBD_CMD_DISC }; - nbd_send_request(s->ioc ?: QIO_CHANNEL(s->sioc), &request); + nbd_send_request(s->ioc, &request); yank_unregister_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), nbd_yank, bs); - object_unref(OBJECT(s->sioc)); - s->sioc = NULL; object_unref(OBJECT(s->ioc)); s->ioc = NULL; - return ret; } - if (!s->ioc) { - s->ioc = QIO_CHANNEL(s->sioc); - object_ref(OBJECT(s->ioc)); - } - return 0; } @@ -2048,6 +2044,7 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, { int ret; BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + QIOChannelSocket *sioc; s->bs = bs; qemu_co_mutex_init(&s->send_mutex); @@ -2069,12 +2066,13 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, * establish TCP connection, return error if it fails * TODO: Configurable retry-until-timeout behaviour. */ - if (nbd_establish_connection(bs, s->saddr, errp) < 0) { + sioc = nbd_establish_connection(bs, s->saddr, errp); + if (!sioc) { ret = -ECONNREFUSED; goto fail; } - ret = nbd_client_handshake(bs, errp); + ret = nbd_client_handshake(bs, sioc, errp); if (ret < 0) { goto fail; } From 43cb34dede464c2e9a51ea33bc246b40db5d68d4 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:56 +0300 Subject: [PATCH 28/34] nbd/client-connection: return only one io channel block/nbd doesn't need underlying sioc channel anymore. So, we can update nbd/client-connection interface to return only one top-most io channel, which is more straight forward. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-27-vsementsov@virtuozzo.com> [eblake: squash in Vladimir's fixes for uninit usage caught by clang] Signed-off-by: Eric Blake --- block/nbd.c | 13 ++----------- include/block/nbd.h | 4 ++-- nbd/client-connection.c | 38 +++++++++++++++++++++++++++++--------- 3 files changed, 33 insertions(+), 22 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 9f193d130b..411435c155 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -360,7 +360,6 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) { int ret; AioContext *aio_context = bdrv_get_aio_context(s->bs); - QIOChannelSocket *sioc; if (!nbd_client_connecting(s)) { return; @@ -399,20 +398,12 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) s->ioc = NULL; } - sioc = nbd_co_establish_connection(s->conn, &s->info, &s->ioc, NULL); - if (!sioc) { + s->ioc = nbd_co_establish_connection(s->conn, &s->info, NULL); + if (!s->ioc) { ret = -ECONNREFUSED; goto out; } - if (s->ioc) { - /* sioc is referenced by s->ioc */ - object_unref(OBJECT(sioc)); - } else { - s->ioc = QIO_CHANNEL(sioc); - } - sioc = NULL; - qio_channel_set_blocking(QIO_CHANNEL(s->ioc), false, NULL); qio_channel_attach_aio_context(QIO_CHANNEL(s->ioc), aio_context); diff --git a/include/block/nbd.h b/include/block/nbd.h index 5bb54d831c..10c8a0bcca 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -418,9 +418,9 @@ NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr, QCryptoTLSCreds *tlscreds); void nbd_client_connection_release(NBDClientConnection *conn); -QIOChannelSocket *coroutine_fn +QIOChannel *coroutine_fn nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info, - QIOChannel **ioc, Error **errp); + Error **errp); void coroutine_fn nbd_co_establish_connection_cancel(NBDClientConnection *conn); diff --git a/nbd/client-connection.c b/nbd/client-connection.c index 883f9cf158..955edafb7c 100644 --- a/nbd/client-connection.c +++ b/nbd/client-connection.c @@ -272,15 +272,14 @@ void nbd_client_connection_release(NBDClientConnection *conn) * nbd_receive_export_list() would be zero (see description of NBDExportInfo in * include/block/nbd.h). */ -QIOChannelSocket *coroutine_fn +QIOChannel *coroutine_fn nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info, - QIOChannel **ioc, Error **errp) + Error **errp) { QemuThread thread; if (conn->do_negotiation) { assert(info); - assert(ioc); } WITH_QEMU_LOCK_GUARD(&conn->mutex) { @@ -294,10 +293,19 @@ nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info, if (conn->sioc) { /* Previous attempt finally succeeded in background */ if (conn->do_negotiation) { - *ioc = g_steal_pointer(&conn->ioc); memcpy(info, &conn->updated_info, sizeof(*info)); + if (conn->ioc) { + /* TLS channel now has own reference to parent */ + object_unref(OBJECT(conn->sioc)); + conn->sioc = NULL; + + return g_steal_pointer(&conn->ioc); + } } - return g_steal_pointer(&conn->sioc); + + assert(!conn->ioc); + + return QIO_CHANNEL(g_steal_pointer(&conn->sioc)); } conn->running = true; @@ -329,11 +337,23 @@ nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info, } else { error_propagate(errp, conn->err); conn->err = NULL; - if (conn->sioc && conn->do_negotiation) { - *ioc = g_steal_pointer(&conn->ioc); - memcpy(info, &conn->updated_info, sizeof(*info)); + if (!conn->sioc) { + return NULL; } - return g_steal_pointer(&conn->sioc); + if (conn->do_negotiation) { + memcpy(info, &conn->updated_info, sizeof(*info)); + if (conn->ioc) { + /* TLS channel now has own reference to parent */ + object_unref(OBJECT(conn->sioc)); + conn->sioc = NULL; + + return g_steal_pointer(&conn->ioc); + } + } + + assert(!conn->ioc); + + return QIO_CHANNEL(g_steal_pointer(&conn->sioc)); } } From bb43694872c344e27d498c0980c50c7effcb448a Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:57 +0300 Subject: [PATCH 29/34] block-coroutine-wrapper: allow non bdrv_ prefix We are going to reuse the script to generate a nbd_ function in further commit. Prepare the script now. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-28-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- scripts/block-coroutine-wrapper.py | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/scripts/block-coroutine-wrapper.py b/scripts/block-coroutine-wrapper.py index 0461fd1c45..85dbeb9ecf 100644 --- a/scripts/block-coroutine-wrapper.py +++ b/scripts/block-coroutine-wrapper.py @@ -98,12 +98,13 @@ def snake_to_camel(func_name: str) -> str: def gen_wrapper(func: FuncDecl) -> str: - assert func.name.startswith('bdrv_') - assert not func.name.startswith('bdrv_co_') + assert not '_co_' in func.name assert func.return_type == 'int' assert func.args[0].type in ['BlockDriverState *', 'BdrvChild *'] - name = 'bdrv_co_' + func.name[5:] + subsystem, subname = func.name.split('_', 1) + + name = f'{subsystem}_co_{subname}' bs = 'bs' if func.args[0].type == 'BlockDriverState *' else 'child->bs' struct_name = snake_to_camel(name) From 51edbf537d2cbf97c8e9defd098b95ca8a18aa8c Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:58 +0300 Subject: [PATCH 30/34] block/nbd: split nbd_co_do_establish_connection out of nbd_reconnect_attempt Split out the part that we want to reuse for nbd_open(). Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210610100802.5888-29-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- block/nbd.c | 82 ++++++++++++++++++++++++++++------------------------- 1 file changed, 43 insertions(+), 39 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 411435c155..8caeafc8d3 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -356,11 +356,50 @@ static int nbd_handle_updated_info(BlockDriverState *bs, Error **errp) return 0; } +static int coroutine_fn nbd_co_do_establish_connection(BlockDriverState *bs, + Error **errp) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + int ret; + + assert(!s->ioc); + + s->ioc = nbd_co_establish_connection(s->conn, &s->info, errp); + if (!s->ioc) { + return -ECONNREFUSED; + } + + ret = nbd_handle_updated_info(s->bs, NULL); + if (ret < 0) { + /* + * We have connected, but must fail for other reasons. + * Send NBD_CMD_DISC as a courtesy to the server. + */ + NBDRequest request = { .type = NBD_CMD_DISC }; + + nbd_send_request(s->ioc, &request); + + object_unref(OBJECT(s->ioc)); + s->ioc = NULL; + + return ret; + } + + qio_channel_set_blocking(s->ioc, false, NULL); + qio_channel_attach_aio_context(s->ioc, bdrv_get_aio_context(bs)); + + yank_register_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank, + bs); + + /* successfully connected */ + s->state = NBD_CLIENT_CONNECTED; + qemu_co_queue_restart_all(&s->free_sema); + + return 0; +} + static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) { - int ret; - AioContext *aio_context = bdrv_get_aio_context(s->bs); - if (!nbd_client_connecting(s)) { return; } @@ -398,42 +437,7 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) s->ioc = NULL; } - s->ioc = nbd_co_establish_connection(s->conn, &s->info, NULL); - if (!s->ioc) { - ret = -ECONNREFUSED; - goto out; - } - - qio_channel_set_blocking(QIO_CHANNEL(s->ioc), false, NULL); - qio_channel_attach_aio_context(QIO_CHANNEL(s->ioc), aio_context); - - yank_register_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank, - s->bs); - - ret = nbd_handle_updated_info(s->bs, NULL); - if (ret < 0) { - /* - * We have connected, but must fail for other reasons. - * Send NBD_CMD_DISC as a courtesy to the server. - */ - NBDRequest request = { .type = NBD_CMD_DISC }; - - nbd_send_request(s->ioc, &request); - - yank_unregister_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), - nbd_yank, s->bs); - object_unref(OBJECT(s->ioc)); - s->ioc = NULL; - - return; - } - -out: - if (ret >= 0) { - /* successfully connected */ - s->state = NBD_CLIENT_CONNECTED; - qemu_co_queue_restart_all(&s->free_sema); - } + nbd_co_do_establish_connection(s->bs, NULL); } static coroutine_fn void nbd_co_reconnect_loop(BDRVNBDState *s) From 97cf89259e4e0455c3b2742911737de5969dc0de Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:07:59 +0300 Subject: [PATCH 31/34] nbd/client-connection: add option for non-blocking connection attempt We'll need a possibility of non-blocking nbd_co_establish_connection(), so that it returns immediately, and it returns success only if a connections was previously established in background. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-30-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 2 +- include/block/nbd.h | 2 +- nbd/client-connection.c | 8 +++++++- 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 8caeafc8d3..bf2e939314 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -364,7 +364,7 @@ static int coroutine_fn nbd_co_do_establish_connection(BlockDriverState *bs, assert(!s->ioc); - s->ioc = nbd_co_establish_connection(s->conn, &s->info, errp); + s->ioc = nbd_co_establish_connection(s->conn, &s->info, true, errp); if (!s->ioc) { return -ECONNREFUSED; } diff --git a/include/block/nbd.h b/include/block/nbd.h index 10c8a0bcca..78d101b774 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -420,7 +420,7 @@ void nbd_client_connection_release(NBDClientConnection *conn); QIOChannel *coroutine_fn nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info, - Error **errp); + bool blocking, Error **errp); void coroutine_fn nbd_co_establish_connection_cancel(NBDClientConnection *conn); diff --git a/nbd/client-connection.c b/nbd/client-connection.c index 955edafb7c..7123b1e189 100644 --- a/nbd/client-connection.c +++ b/nbd/client-connection.c @@ -266,6 +266,8 @@ void nbd_client_connection_release(NBDClientConnection *conn) * otherwise the thread is not running, so start a thread and wait for * completion * + * If @blocking is false, don't wait for the thread, return immediately. + * * If @info is not NULL, also do nbd-negotiation after successful connection. * In this case info is used only as out parameter, and is fully initialized by * nbd_co_establish_connection(). "IN" fields of info as well as related only to @@ -274,7 +276,7 @@ void nbd_client_connection_release(NBDClientConnection *conn) */ QIOChannel *coroutine_fn nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info, - Error **errp) + bool blocking, Error **errp) { QemuThread thread; @@ -315,6 +317,10 @@ nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info, connect_thread_func, conn, QEMU_THREAD_DETACHED); } + if (!blocking) { + return NULL; + } + conn->wait_co = qemu_coroutine_self(); } From a71d597b989fd701b923f09b3c20ac4fcaa55e81 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:08:00 +0300 Subject: [PATCH 32/34] block/nbd: reuse nbd_co_do_establish_connection() in nbd_open() The only last step we need to reuse the function is coroutine-wrapper. nbd_open() may be called from non-coroutine context. So, generate the wrapper and use it. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-31-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/coroutines.h | 6 +++ block/nbd.c | 103 +++------------------------------------------ 2 files changed, 11 insertions(+), 98 deletions(-) diff --git a/block/coroutines.h b/block/coroutines.h index 4cfb4946e6..514d169d23 100644 --- a/block/coroutines.h +++ b/block/coroutines.h @@ -66,4 +66,10 @@ int coroutine_fn bdrv_co_readv_vmstate(BlockDriverState *bs, int coroutine_fn bdrv_co_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); +int generated_co_wrapper +nbd_do_establish_connection(BlockDriverState *bs, Error **errp); +int coroutine_fn +nbd_co_do_establish_connection(BlockDriverState *bs, Error **errp); + + #endif /* BLOCK_COROUTINES_INT_H */ diff --git a/block/nbd.c b/block/nbd.c index bf2e939314..5e7e238b47 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -44,6 +44,7 @@ #include "block/qdict.h" #include "block/nbd.h" #include "block/block_int.h" +#include "block/coroutines.h" #include "qemu/yank.h" @@ -99,11 +100,6 @@ typedef struct BDRVNBDState { NBDClientConnection *conn; } BDRVNBDState; -static QIOChannelSocket *nbd_establish_connection(BlockDriverState *bs, - SocketAddress *saddr, - Error **errp); -static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc, - Error **errp); static void nbd_yank(void *opaque); static void nbd_clear_bdrvstate(BlockDriverState *bs) @@ -356,8 +352,8 @@ static int nbd_handle_updated_info(BlockDriverState *bs, Error **errp) return 0; } -static int coroutine_fn nbd_co_do_establish_connection(BlockDriverState *bs, - Error **errp) +int coroutine_fn nbd_co_do_establish_connection(BlockDriverState *bs, + Error **errp) { BDRVNBDState *s = (BDRVNBDState *)bs->opaque; int ret; @@ -1573,83 +1569,6 @@ static void nbd_client_close(BlockDriverState *bs) nbd_teardown_connection(bs); } -static QIOChannelSocket *nbd_establish_connection(BlockDriverState *bs, - SocketAddress *saddr, - Error **errp) -{ - ERRP_GUARD(); - QIOChannelSocket *sioc; - - sioc = qio_channel_socket_new(); - qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client"); - - qio_channel_socket_connect_sync(sioc, saddr, errp); - if (*errp) { - object_unref(OBJECT(sioc)); - return NULL; - } - - yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), nbd_yank, bs); - qio_channel_set_delay(QIO_CHANNEL(sioc), false); - - return sioc; -} - -/* nbd_client_handshake takes ownership on sioc. */ -static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc, - Error **errp) -{ - BDRVNBDState *s = (BDRVNBDState *)bs->opaque; - AioContext *aio_context = bdrv_get_aio_context(bs); - int ret; - - trace_nbd_client_handshake(s->export); - qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL); - qio_channel_attach_aio_context(QIO_CHANNEL(sioc), aio_context); - - s->info.request_sizes = true; - s->info.structured_reply = true; - s->info.base_allocation = true; - s->info.x_dirty_bitmap = g_strdup(s->x_dirty_bitmap); - s->info.name = g_strdup(s->export ?: ""); - ret = nbd_receive_negotiate(aio_context, QIO_CHANNEL(sioc), s->tlscreds, - s->hostname, &s->ioc, &s->info, errp); - g_free(s->info.x_dirty_bitmap); - g_free(s->info.name); - if (ret < 0) { - yank_unregister_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), - nbd_yank, bs); - object_unref(OBJECT(sioc)); - return ret; - } - - if (s->ioc) { - /* sioc is referenced by s->ioc */ - object_unref(OBJECT(sioc)); - } else { - s->ioc = QIO_CHANNEL(sioc); - } - sioc = NULL; - - ret = nbd_handle_updated_info(bs, errp); - if (ret < 0) { - /* - * We have connected, but must fail for other reasons. - * Send NBD_CMD_DISC as a courtesy to the server. - */ - NBDRequest request = { .type = NBD_CMD_DISC }; - - nbd_send_request(s->ioc, &request); - - yank_unregister_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), - nbd_yank, bs); - object_unref(OBJECT(s->ioc)); - s->ioc = NULL; - return ret; - } - - return 0; -} /* * Parse nbd_open options @@ -2039,7 +1958,6 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, { int ret; BDRVNBDState *s = (BDRVNBDState *)bs->opaque; - QIOChannelSocket *sioc; s->bs = bs; qemu_co_mutex_init(&s->send_mutex); @@ -2057,22 +1975,11 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags, s->conn = nbd_client_connection_new(s->saddr, true, s->export, s->x_dirty_bitmap, s->tlscreds); - /* - * establish TCP connection, return error if it fails - * TODO: Configurable retry-until-timeout behaviour. - */ - sioc = nbd_establish_connection(bs, s->saddr, errp); - if (!sioc) { - ret = -ECONNREFUSED; - goto fail; - } - - ret = nbd_client_handshake(bs, sioc, errp); + /* TODO: Configurable retry-until-timeout behaviour. */ + ret = nbd_do_establish_connection(bs, errp); if (ret < 0) { goto fail; } - /* successfully connected */ - s->state = NBD_CLIENT_CONNECTED; s->connection_co = qemu_coroutine_create(nbd_connection_entry, s); bdrv_inc_in_flight(bs); From 91e0998f5ab88e575b5d1b9bc55e0d179b9224f1 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:08:01 +0300 Subject: [PATCH 33/34] block/nbd: add nbd_client_connected() helper We already have two similar helpers for other state. Let's add another one for convenience. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-32-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 5e7e238b47..5cfb749e08 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -122,15 +122,20 @@ static void nbd_clear_bdrvstate(BlockDriverState *bs) s->x_dirty_bitmap = NULL; } +static bool nbd_client_connected(BDRVNBDState *s) +{ + return qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTED; +} + static void nbd_channel_error(BDRVNBDState *s, int ret) { if (ret == -EIO) { - if (qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTED) { + if (nbd_client_connected(s)) { s->state = s->reconnect_delay ? NBD_CLIENT_CONNECTING_WAIT : NBD_CLIENT_CONNECTING_NOWAIT; } } else { - if (qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTED) { + if (nbd_client_connected(s)) { qio_channel_shutdown(s->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); } s->state = NBD_CLIENT_QUIT; @@ -228,7 +233,7 @@ static void nbd_client_attach_aio_context(BlockDriverState *bs, * s->connection_co is either yielded from nbd_receive_reply or from * nbd_co_reconnect_loop() */ - if (qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTED) { + if (nbd_client_connected(s)) { qio_channel_attach_aio_context(QIO_CHANNEL(s->ioc), new_context); } @@ -499,7 +504,7 @@ static coroutine_fn void nbd_connection_entry(void *opaque) nbd_co_reconnect_loop(s); } - if (qatomic_load_acquire(&s->state) != NBD_CLIENT_CONNECTED) { + if (!nbd_client_connected(s)) { continue; } @@ -578,7 +583,7 @@ static int nbd_co_send_request(BlockDriverState *bs, qemu_co_queue_wait(&s->free_sema, &s->send_mutex); } - if (qatomic_load_acquire(&s->state) != NBD_CLIENT_CONNECTED) { + if (!nbd_client_connected(s)) { rc = -EIO; goto err; } @@ -605,8 +610,7 @@ static int nbd_co_send_request(BlockDriverState *bs, if (qiov) { qio_channel_set_cork(s->ioc, true); rc = nbd_send_request(s->ioc, request); - if (qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTED && - rc >= 0) { + if (nbd_client_connected(s) && rc >= 0) { if (qio_channel_writev_all(s->ioc, qiov->iov, qiov->niov, NULL) < 0) { rc = -EIO; @@ -931,7 +935,7 @@ static coroutine_fn int nbd_co_do_receive_one_chunk( s->requests[i].receiving = true; qemu_coroutine_yield(); s->requests[i].receiving = false; - if (qatomic_load_acquire(&s->state) != NBD_CLIENT_CONNECTED) { + if (!nbd_client_connected(s)) { error_setg(errp, "Connection closed"); return -EIO; } @@ -1090,7 +1094,7 @@ static bool nbd_reply_chunk_iter_receive(BDRVNBDState *s, NBDReply local_reply; NBDStructuredReplyChunk *chunk; Error *local_err = NULL; - if (qatomic_load_acquire(&s->state) != NBD_CLIENT_CONNECTED) { + if (!nbd_client_connected(s)) { error_setg(&local_err, "Connection closed"); nbd_iter_channel_error(iter, -EIO, &local_err); goto break_loop; @@ -1115,8 +1119,7 @@ static bool nbd_reply_chunk_iter_receive(BDRVNBDState *s, } /* Do not execute the body of NBD_FOREACH_REPLY_CHUNK for simple reply. */ - if (nbd_reply_is_simple(reply) || - qatomic_load_acquire(&s->state) != NBD_CLIENT_CONNECTED) { + if (nbd_reply_is_simple(reply) || !nbd_client_connected(s)) { goto break_loop; } From bbfb7c2f350262f893642433dea66352fc168295 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:08:02 +0300 Subject: [PATCH 34/34] block/nbd: safer transition to receiving request req->receiving is a flag of request being in one concrete yield point in nbd_co_do_receive_one_chunk(). Such kind of boolean flag is always better to unset before scheduling the coroutine, to avoid double scheduling. So, let's be more careful. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-33-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/nbd.c b/block/nbd.c index 5cfb749e08..3cbee762de 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -150,6 +150,7 @@ static void nbd_recv_coroutines_wake_all(BDRVNBDState *s) NBDClientRequest *req = &s->requests[i]; if (req->coroutine && req->receiving) { + req->receiving = false; aio_co_wake(req->coroutine); } } @@ -548,6 +549,7 @@ static coroutine_fn void nbd_connection_entry(void *opaque) * connection_co happens through a bottom half, which can only * run after we yield. */ + s->requests[i].receiving = false; aio_co_wake(s->requests[i].coroutine); qemu_coroutine_yield(); } @@ -934,7 +936,7 @@ static coroutine_fn int nbd_co_do_receive_one_chunk( /* Wait until we're woken up by nbd_connection_entry. */ s->requests[i].receiving = true; qemu_coroutine_yield(); - s->requests[i].receiving = false; + assert(!s->requests[i].receiving); if (!nbd_client_connected(s)) { error_setg(errp, "Connection closed"); return -EIO;