@@ -1,6 +1,7 @@
/*
* QEMU Block driver for NBD
*
+ * Copyright (c) 2019 Virtuozzo International GmbH.
* Copyright (C) 2016 Red Hat, Inc.
* Copyright (C) 2008 Bull S.A.S.
* Author: Laurent Vivier <Laurent.Vivier@bull.net>
@@ -55,6 +56,8 @@ typedef struct {
} NBDClientRequest;
typedef enum NBDClientState {
+ NBD_CLIENT_CONNECTING_WAIT,
+ NBD_CLIENT_CONNECTING_NOWAIT,
NBD_CLIENT_CONNECTED,
NBD_CLIENT_QUIT
} NBDClientState;
@@ -67,8 +70,14 @@ typedef struct BDRVNBDState {
CoMutex send_mutex;
CoQueue free_sema;
Coroutine *connection_co;
+ QemuCoSleepState *connection_co_sleep_ns_state;
+ bool drained;
+ bool wait_drained_end;
int in_flight;
NBDClientState state;
+ int connect_status;
+ Error *connect_err;
+ bool wait_in_flight;
NBDClientRequest requests[MAX_NBD_REQUESTS];
NBDReply reply;
@@ -83,10 +92,21 @@ typedef struct BDRVNBDState {
char *x_dirty_bitmap;
} BDRVNBDState;
-/* @ret will be used for reconnect in future */
+static int nbd_client_connect(BlockDriverState *bs, Error **errp);
+
static void nbd_channel_error(BDRVNBDState *s, int ret)
{
- s->state = NBD_CLIENT_QUIT;
+ if (ret == -EIO) {
+ if (s->state == NBD_CLIENT_CONNECTED) {
+ s->state = s->reconnect_delay ? NBD_CLIENT_CONNECTING_WAIT :
+ NBD_CLIENT_CONNECTING_NOWAIT;
+ }
+ } else {
+ if (s->state == NBD_CLIENT_CONNECTED) {
+ qio_channel_shutdown(s->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
+ }
+ s->state = NBD_CLIENT_QUIT;
+ }
}
static void nbd_recv_coroutines_wake_all(BDRVNBDState *s)
@@ -129,7 +149,13 @@ static void nbd_client_attach_aio_context(BlockDriverState *bs,
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
- qio_channel_attach_aio_context(QIO_CHANNEL(s->ioc), new_context);
+ /*
+ * s->connection_co is either yielded from nbd_receive_reply or from
+ * nbd_co_reconnect_loop()
+ */
+ if (s->state == NBD_CLIENT_CONNECTED) {
+ qio_channel_attach_aio_context(QIO_CHANNEL(s->ioc), new_context);
+ }
bdrv_inc_in_flight(bs);
@@ -140,24 +166,150 @@ static void nbd_client_attach_aio_context(BlockDriverState *bs,
aio_wait_bh_oneshot(new_context, nbd_client_attach_aio_context_bh, bs);
}
+static void coroutine_fn nbd_client_co_drain_begin(BlockDriverState *bs)
+{
+ BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
-static void nbd_teardown_connection(BlockDriverState *bs)
+ s->drained = true;
+ if (s->connection_co_sleep_ns_state) {
+ qemu_co_sleep_wake(s->connection_co_sleep_ns_state);
+ }
+}
+
+static void coroutine_fn nbd_client_co_drain_end(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
- assert(s->ioc);
+ s->drained = false;
+ if (s->wait_drained_end) {
+ s->wait_drained_end = false;
+ aio_co_wake(s->connection_co);
+ }
+}
+
- /* finish any pending coroutines */
- qio_channel_shutdown(s->ioc,
- QIO_CHANNEL_SHUTDOWN_BOTH,
- NULL);
+static void nbd_teardown_connection(BlockDriverState *bs)
+{
+ BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
+
+ if (s->state == NBD_CLIENT_CONNECTED) {
+ /* finish any pending coroutines */
+ assert(s->ioc);
+ qio_channel_shutdown(s->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
+ }
+ s->state = NBD_CLIENT_QUIT;
+ if (s->connection_co) {
+ if (s->connection_co_sleep_ns_state) {
+ qemu_co_sleep_wake(s->connection_co_sleep_ns_state);
+ }
+ }
BDRV_POLL_WHILE(bs, s->connection_co);
+}
- nbd_client_detach_aio_context(bs);
- object_unref(OBJECT(s->sioc));
- s->sioc = NULL;
- object_unref(OBJECT(s->ioc));
- s->ioc = NULL;
+static bool nbd_client_connecting(BDRVNBDState *s)
+{
+ return s->state == NBD_CLIENT_CONNECTING_WAIT ||
+ s->state == NBD_CLIENT_CONNECTING_NOWAIT;
+}
+
+static bool nbd_client_connecting_wait(BDRVNBDState *s)
+{
+ return s->state == NBD_CLIENT_CONNECTING_WAIT;
+}
+
+static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s)
+{
+ Error *local_err = NULL;
+
+ if (!nbd_client_connecting(s)) {
+ return;
+ }
+
+ /* Wait for completion of all in-flight requests */
+
+ qemu_co_mutex_lock(&s->send_mutex);
+
+ while (s->in_flight > 0) {
+ qemu_co_mutex_unlock(&s->send_mutex);
+ nbd_recv_coroutines_wake_all(s);
+ s->wait_in_flight = true;
+ qemu_coroutine_yield();
+ s->wait_in_flight = false;
+ qemu_co_mutex_lock(&s->send_mutex);
+ }
+
+ qemu_co_mutex_unlock(&s->send_mutex);
+
+ if (!nbd_client_connecting(s)) {
+ return;
+ }
+
+ /*
+ * Now we are sure that nobody is accessing the channel, and no one will
+ * try until we set the state to CONNECTED.
+ */
+
+ /* Finalize previous connection if any */
+ if (s->ioc) {
+ nbd_client_detach_aio_context(s->bs);
+ object_unref(OBJECT(s->sioc));
+ s->sioc = NULL;
+ object_unref(OBJECT(s->ioc));
+ s->ioc = NULL;
+ }
+
+ s->connect_status = nbd_client_connect(s->bs, &local_err);
+ error_free(s->connect_err);
+ s->connect_err = NULL;
+ error_propagate(&s->connect_err, local_err);
+
+ if (s->connect_status < 0) {
+ /* failed attempt */
+ return;
+ }
+
+ /* successfully connected */
+ s->state = NBD_CLIENT_CONNECTED;
+ qemu_co_queue_restart_all(&s->free_sema);
+}
+
+static coroutine_fn void nbd_co_reconnect_loop(BDRVNBDState *s)
+{
+ uint64_t start_time_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
+ uint64_t delay_ns = s->reconnect_delay * NANOSECONDS_PER_SECOND;
+ uint64_t timeout = 1 * NANOSECONDS_PER_SECOND;
+ uint64_t max_timeout = 16 * NANOSECONDS_PER_SECOND;
+
+ nbd_reconnect_attempt(s);
+
+ while (nbd_client_connecting(s)) {
+ if (s->state == NBD_CLIENT_CONNECTING_WAIT &&
+ qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - start_time_ns > delay_ns)
+ {
+ s->state = NBD_CLIENT_CONNECTING_NOWAIT;
+ qemu_co_queue_restart_all(&s->free_sema);
+ }
+
+ qemu_co_sleep_ns_wakeable(QEMU_CLOCK_REALTIME, timeout,
+ &s->connection_co_sleep_ns_state);
+ if (s->drained) {
+ bdrv_dec_in_flight(s->bs);
+ 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();
+ }
+ bdrv_inc_in_flight(s->bs);
+ }
+ if (timeout < max_timeout) {
+ timeout *= 2;
+ }
+
+ nbd_reconnect_attempt(s);
+ }
}
static coroutine_fn void nbd_connection_entry(void *opaque)
@@ -177,16 +329,26 @@ static coroutine_fn void nbd_connection_entry(void *opaque)
* Therefore we keep an additional in_flight reference all the time and
* only drop it temporarily here.
*/
+
+ if (nbd_client_connecting(s)) {
+ nbd_co_reconnect_loop(s);
+ }
+
+ if (s->state != NBD_CLIENT_CONNECTED) {
+ continue;
+ }
+
assert(s->reply.handle == 0);
ret = nbd_receive_reply(s->bs, s->ioc, &s->reply, &local_err);
if (local_err) {
trace_nbd_read_reply_entry_fail(ret, error_get_pretty(local_err));
error_free(local_err);
+ local_err = NULL;
}
if (ret <= 0) {
nbd_channel_error(s, ret ? ret : -EIO);
- break;
+ continue;
}
/*
@@ -201,7 +363,7 @@ static coroutine_fn void nbd_connection_entry(void *opaque)
(nbd_reply_is_structured(&s->reply) && !s->info.structured_reply))
{
nbd_channel_error(s, -EINVAL);
- break;
+ continue;
}
/*
@@ -220,10 +382,19 @@ static coroutine_fn void nbd_connection_entry(void *opaque)
qemu_coroutine_yield();
}
+ qemu_co_queue_restart_all(&s->free_sema);
nbd_recv_coroutines_wake_all(s);
bdrv_dec_in_flight(s->bs);
s->connection_co = NULL;
+ if (s->ioc) {
+ nbd_client_detach_aio_context(s->bs);
+ object_unref(OBJECT(s->sioc));
+ s->sioc = NULL;
+ object_unref(OBJECT(s->ioc));
+ s->ioc = NULL;
+ }
+
aio_wait_kick();
}
@@ -235,7 +406,7 @@ static int nbd_co_send_request(BlockDriverState *bs,
int rc, i = -1;
qemu_co_mutex_lock(&s->send_mutex);
- while (s->in_flight == MAX_NBD_REQUESTS) {
+ while (s->in_flight == MAX_NBD_REQUESTS || nbd_client_connecting_wait(s)) {
qemu_co_queue_wait(&s->free_sema, &s->send_mutex);
}
@@ -286,7 +457,11 @@ err:
s->requests[i].coroutine = NULL;
s->in_flight--;
}
- qemu_co_queue_next(&s->free_sema);
+ if (s->in_flight == 0 && s->wait_in_flight) {
+ aio_co_wake(s->connection_co);
+ } else {
+ qemu_co_queue_next(&s->free_sema);
+ }
}
qemu_co_mutex_unlock(&s->send_mutex);
return rc;
@@ -666,10 +841,15 @@ static coroutine_fn int nbd_co_receive_one_chunk(
} else {
/* For assert at loop start in nbd_connection_entry */
*reply = s->reply;
- s->reply.handle = 0;
}
+ s->reply.handle = 0;
- if (s->connection_co) {
+ if (s->connection_co && !s->wait_in_flight) {
+ /*
+ * We must check s->wait_in_flight, because we may entered by
+ * nbd_recv_coroutines_wake_all(), in this case we should not
+ * wake connection_co here, it will woken by last request.
+ */
aio_co_wake(s->connection_co);
}
@@ -781,7 +961,11 @@ break_loop:
qemu_co_mutex_lock(&s->send_mutex);
s->in_flight--;
- qemu_co_queue_next(&s->free_sema);
+ if (s->in_flight == 0 && s->wait_in_flight) {
+ aio_co_wake(s->connection_co);
+ } else {
+ qemu_co_queue_next(&s->free_sema);
+ }
qemu_co_mutex_unlock(&s->send_mutex);
return false;
@@ -927,20 +1111,26 @@ static int nbd_co_request(BlockDriverState *bs, NBDRequest *request,
} else {
assert(request->type != NBD_CMD_WRITE);
}
- ret = nbd_co_send_request(bs, request, write_qiov);
- if (ret < 0) {
- return ret;
- }
- ret = nbd_co_receive_return_code(s, request->handle,
- &request_ret, &local_err);
- if (local_err) {
- trace_nbd_co_request_fail(request->from, request->len, request->handle,
- request->flags, request->type,
- nbd_cmd_lookup(request->type),
- ret, error_get_pretty(local_err));
- error_free(local_err);
- }
+ do {
+ ret = nbd_co_send_request(bs, request, write_qiov);
+ if (ret < 0) {
+ continue;
+ }
+
+ ret = nbd_co_receive_return_code(s, request->handle,
+ &request_ret, &local_err);
+ if (local_err) {
+ trace_nbd_co_request_fail(request->from, request->len,
+ request->handle, request->flags,
+ request->type,
+ nbd_cmd_lookup(request->type),
+ ret, error_get_pretty(local_err));
+ error_free(local_err);
+ local_err = NULL;
+ }
+ } while (ret < 0 && nbd_client_connecting_wait(s));
+
return ret ? ret : request_ret;
}
@@ -981,20 +1171,24 @@ static int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
request.len -= slop;
}
- ret = nbd_co_send_request(bs, &request, NULL);
- if (ret < 0) {
- return ret;
- }
+ do {
+ ret = nbd_co_send_request(bs, &request, NULL);
+ if (ret < 0) {
+ continue;
+ }
+
+ ret = nbd_co_receive_cmdread_reply(s, request.handle, offset, qiov,
+ &request_ret, &local_err);
+ if (local_err) {
+ trace_nbd_co_request_fail(request.from, request.len, request.handle,
+ request.flags, request.type,
+ nbd_cmd_lookup(request.type),
+ ret, error_get_pretty(local_err));
+ error_free(local_err);
+ local_err = NULL;
+ }
+ } while (ret < 0 && nbd_client_connecting_wait(s));
- ret = nbd_co_receive_cmdread_reply(s, request.handle, offset, qiov,
- &request_ret, &local_err);
- if (local_err) {
- trace_nbd_co_request_fail(request.from, request.len, request.handle,
- request.flags, request.type,
- nbd_cmd_lookup(request.type),
- ret, error_get_pretty(local_err));
- error_free(local_err);
- }
return ret ? ret : request_ret;
}
@@ -1131,20 +1325,25 @@ static int coroutine_fn nbd_client_co_block_status(
if (s->info.min_block) {
assert(QEMU_IS_ALIGNED(request.len, s->info.min_block));
}
- ret = nbd_co_send_request(bs, &request, NULL);
- if (ret < 0) {
- return ret;
- }
+ do {
+ ret = nbd_co_send_request(bs, &request, NULL);
+ if (ret < 0) {
+ continue;
+ }
+
+ ret = nbd_co_receive_blockstatus_reply(s, request.handle, bytes,
+ &extent, &request_ret,
+ &local_err);
+ if (local_err) {
+ trace_nbd_co_request_fail(request.from, request.len, request.handle,
+ request.flags, request.type,
+ nbd_cmd_lookup(request.type),
+ ret, error_get_pretty(local_err));
+ error_free(local_err);
+ local_err = NULL;
+ }
+ } while (ret < 0 && nbd_client_connecting_wait(s));
- ret = nbd_co_receive_blockstatus_reply(s, request.handle, bytes,
- &extent, &request_ret, &local_err);
- if (local_err) {
- trace_nbd_co_request_fail(request.from, request.len, request.handle,
- request.flags, request.type,
- nbd_cmd_lookup(request.type),
- ret, error_get_pretty(local_err));
- error_free(local_err);
- }
if (ret < 0 || request_ret < 0) {
return ret ? ret : request_ret;
}
@@ -1163,9 +1362,9 @@ static void nbd_client_close(BlockDriverState *bs)
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
NBDRequest request = { .type = NBD_CMD_DISC };
- assert(s->ioc);
-
- nbd_send_request(s->ioc, &request);
+ if (s->ioc) {
+ nbd_send_request(s->ioc, &request);
+ }
nbd_teardown_connection(bs);
}
@@ -1808,6 +2007,8 @@ static BlockDriver bdrv_nbd = {
.bdrv_getlength = nbd_getlength,
.bdrv_detach_aio_context = nbd_client_detach_aio_context,
.bdrv_attach_aio_context = nbd_client_attach_aio_context,
+ .bdrv_co_drain_begin = nbd_client_co_drain_begin,
+ .bdrv_co_drain_end = nbd_client_co_drain_end,
.bdrv_refresh_filename = nbd_refresh_filename,
.bdrv_co_block_status = nbd_client_co_block_status,
.bdrv_dirname = nbd_dirname,
@@ -1830,6 +2031,8 @@ static BlockDriver bdrv_nbd_tcp = {
.bdrv_getlength = nbd_getlength,
.bdrv_detach_aio_context = nbd_client_detach_aio_context,
.bdrv_attach_aio_context = nbd_client_attach_aio_context,
+ .bdrv_co_drain_begin = nbd_client_co_drain_begin,
+ .bdrv_co_drain_end = nbd_client_co_drain_end,
.bdrv_refresh_filename = nbd_refresh_filename,
.bdrv_co_block_status = nbd_client_co_block_status,
.bdrv_dirname = nbd_dirname,
@@ -1852,6 +2055,8 @@ static BlockDriver bdrv_nbd_unix = {
.bdrv_getlength = nbd_getlength,
.bdrv_detach_aio_context = nbd_client_detach_aio_context,
.bdrv_attach_aio_context = nbd_client_attach_aio_context,
+ .bdrv_co_drain_begin = nbd_client_co_drain_begin,
+ .bdrv_co_drain_end = nbd_client_co_drain_end,
.bdrv_refresh_filename = nbd_refresh_filename,
.bdrv_co_block_status = nbd_client_co_block_status,
.bdrv_dirname = nbd_dirname,
Implement reconnect. To achieve this: 1. add new modes: connecting-wait: means, that reconnecting is in progress, and there were small number of reconnect attempts, so all requests are waiting for the connection. connecting-nowait: reconnecting is in progress, there were a lot of attempts of reconnect, all requests will return errors. two old modes are used too: connected: normal state quit: exiting after fatal error or on close Possible transitions are: * -> quit connecting-* -> connected connecting-wait -> connecting-nowait (transition is done after reconnect-delay seconds in connecting-wait mode) connected -> connecting-wait 2. Implement reconnect in connection_co. So, in connecting-* mode, connection_co, tries to reconnect unlimited times. 3. Retry nbd queries on channel error, if we are in connecting-wait state. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> --- block/nbd.c | 331 ++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 268 insertions(+), 63 deletions(-)