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qemu-e2k/block/nbd.c
Vladimir Sementsov-Ogievskiy 1dc4718d84 block/nbd: use non-blocking connect: fix vm hang on connect() 
This makes nbd's connection_co yield during reconnects, so that
reconnect doesn't block the main thread. This is very important in
case of an unavailable nbd server host: connect() call may take a long
time, blocking the main thread (and due to reconnect, it will hang
again and again with small gaps of working time during pauses between
connection attempts).

Realization notes:

 - We don't want to implement non-blocking connect() over non-blocking
 socket, because getaddrinfo() doesn't have portable non-blocking
 realization anyway, so let's just use a thread for both getaddrinfo()
 and connect().

 - We can't use qio_channel_socket_connect_async (which behaves
 similarly and starts a thread to execute connect() call), as it's relying
 on someone iterating main loop (g_main_loop_run() or something like
 this), which is not always the case.

 - We can't use thread_pool_submit_co API, as thread pool waits for all
 threads to finish (but we don't want to wait for blocking reconnect
 attempt on shutdown.

 So, we just create the thread by hand. Some additional difficulties
 are:

 - We want our connect to avoid blocking drained sections and aio context
 switches. To achieve this, we make it possible to "cancel" synchronous
 wait for the connect (which is a coroutine yield actually), still,
 the thread continues in background, and if successful, its result may be
 reused on next reconnect attempt.

 - We don't want to wait for reconnect on shutdown, so there is
 CONNECT_THREAD_RUNNING_DETACHED thread state, which means that the block
 layer is no longer interested in a result, and thread should close new
 connected socket on finish and free the state.

How to reproduce the bug, fixed with this commit:

1. Create an image on node1:
   qemu-img create -f qcow2 xx 100M

2. Start NBD server on node1:
   qemu-nbd xx

3. Start vm with second nbd disk on node2, like this:

  ./x86_64-softmmu/qemu-system-x86_64 -nodefaults -drive \
    file=/work/images/cent7.qcow2 -drive file=nbd+tcp://192.168.100.2 \
    -vnc :0 -qmp stdio -m 2G -enable-kvm -vga std

4. Access the vm through vnc (or some other way?), and check that NBD
   drive works:

   dd if=/dev/sdb of=/dev/null bs=1M count=10

   - the command should succeed.

5. Now, let's trigger nbd-reconnect loop in Qemu process. For this:

5.1 Kill NBD server on node1

5.2 run "dd if=/dev/sdb of=/dev/null bs=1M count=10" in the guest
    again. The command should fail and a lot of error messages about
    failing disk may appear as well.

    Now NBD client driver in Qemu tries to reconnect.
    Still, VM works well.

6. Make node1 unavailable on NBD port, so connect() from node2 will
   last for a long time:

   On node1 (Note, that 10809 is just a default NBD port):

   sudo iptables -A INPUT -p tcp --dport 10809 -j DROP

   After some time the guest hangs, and you may check in gdb that Qemu
   hangs in connect() call, issued from the main thread. This is the
   BUG.

7. Don't forget to drop iptables rule from your node1:

   sudo iptables -D INPUT -p tcp --dport 10809 -j DROP

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200812145237.4396-1-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: minor wording and formatting tweaks]
Signed-off-by: Eric Blake <eblake@redhat.com>
2020-09-02 16:47:23 -05:00

2449 lines
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/*
* 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>
*
* Some parts:
* Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
*
* 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 "trace.h"
#include "qemu/uri.h"
#include "qemu/option.h"
#include "qemu/cutils.h"
#include "qemu/main-loop.h"
#include "qapi/qapi-visit-sockets.h"
#include "qapi/qmp/qstring.h"
#include "qapi/clone-visitor.h"
#include "block/qdict.h"
#include "block/nbd.h"
#include "block/block_int.h"
#define EN_OPTSTR ":exportname="
#define MAX_NBD_REQUESTS 16
#define HANDLE_TO_INDEX(bs, handle) ((handle) ^ (uint64_t)(intptr_t)(bs))
#define INDEX_TO_HANDLE(bs, index) ((index) ^ (uint64_t)(intptr_t)(bs))
typedef struct {
Coroutine *coroutine;
uint64_t offset; /* original offset of the request */
bool receiving; /* waiting for connection_co? */
} NBDClientRequest;
typedef enum NBDClientState {
NBD_CLIENT_CONNECTING_WAIT,
NBD_CLIENT_CONNECTING_NOWAIT,
NBD_CLIENT_CONNECTED,
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 */
/*
* 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.
* If you want to steal error, don't forget to set pointer to NULL.
*/
QIOChannelSocket *sioc;
Error *err;
/* state and bh_ctx are protected by mutex */
QemuMutex mutex;
NBDConnectThreadState state; /* current state of the thread */
AioContext *bh_ctx; /* where to schedule bh (NULL means don't schedule) */
} NBDConnectThread;
typedef struct BDRVNBDState {
QIOChannelSocket *sioc; /* The master data channel */
QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
NBDExportInfo info;
CoMutex send_mutex;
CoQueue free_sema;
Coroutine *connection_co;
Coroutine *teardown_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;
BlockDriverState *bs;
/* Connection parameters */
uint32_t reconnect_delay;
SocketAddress *saddr;
char *export, *tlscredsid;
QCryptoTLSCreds *tlscreds;
const char *hostname;
char *x_dirty_bitmap;
bool wait_connect;
NBDConnectThread *connect_thread;
} BDRVNBDState;
static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
Error **errp);
static QIOChannelSocket *nbd_co_establish_connection(BlockDriverState *bs,
Error **errp);
static void nbd_co_establish_connection_cancel(BlockDriverState *bs,
bool detach);
static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc,
Error **errp);
static void nbd_clear_bdrvstate(BDRVNBDState *s)
{
object_unref(OBJECT(s->tlscreds));
qapi_free_SocketAddress(s->saddr);
s->saddr = NULL;
g_free(s->export);
s->export = NULL;
g_free(s->tlscredsid);
s->tlscredsid = NULL;
g_free(s->x_dirty_bitmap);
s->x_dirty_bitmap = NULL;
}
static void nbd_channel_error(BDRVNBDState *s, int ret)
{
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)
{
int i;
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
NBDClientRequest *req = &s->requests[i];
if (req->coroutine && req->receiving) {
aio_co_wake(req->coroutine);
}
}
}
static void nbd_client_detach_aio_context(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
qio_channel_detach_aio_context(QIO_CHANNEL(s->ioc));
}
static void nbd_client_attach_aio_context_bh(void *opaque)
{
BlockDriverState *bs = opaque;
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
/*
* The node is still drained, so we know the coroutine has yielded in
* nbd_read_eof(), the only place where bs->in_flight can reach 0, or it is
* entered for the first time. Both places are safe for entering the
* coroutine.
*/
qemu_aio_coroutine_enter(bs->aio_context, s->connection_co);
bdrv_dec_in_flight(bs);
}
static void nbd_client_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
/*
* 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);
/*
* Need to wait here for the BH to run because the BH must run while the
* node is still drained.
*/
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;
s->drained = true;
if (s->connection_co_sleep_ns_state) {
qemu_co_sleep_wake(s->connection_co_sleep_ns_state);
}
nbd_co_establish_connection_cancel(bs, false);
}
static void coroutine_fn nbd_client_co_drain_end(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
s->drained = false;
if (s->wait_drained_end) {
s->wait_drained_end = false;
aio_co_wake(s->connection_co);
}
}
static void nbd_teardown_connection(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
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;
if (s->connection_co) {
if (s->connection_co_sleep_ns_state) {
qemu_co_sleep_wake(s->connection_co_sleep_ns_state);
}
nbd_co_establish_connection_cancel(bs, true);
}
if (qemu_in_coroutine()) {
s->teardown_co = qemu_coroutine_self();
/* connection_co resumes us when it terminates */
qemu_coroutine_yield();
s->teardown_co = NULL;
} else {
BDRV_POLL_WHILE(bs, s->connection_co);
}
assert(!s->connection_co);
}
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 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);
*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);
}
static void nbd_free_connect_thread(NBDConnectThread *thr)
{
if (thr->sioc) {
qio_channel_close(QIO_CHANNEL(thr->sioc), NULL);
}
error_free(thr->err);
qapi_free_SocketAddress(thr->saddr);
g_free(thr);
}
static void *connect_thread_func(void *opaque)
{
NBDConnectThread *thr = opaque;
int ret;
bool do_free = false;
thr->sioc = qio_channel_socket_new();
error_free(thr->err);
thr->err = NULL;
ret = qio_channel_socket_connect_sync(thr->sioc, thr->saddr, &thr->err);
if (ret < 0) {
object_unref(OBJECT(thr->sioc));
thr->sioc = NULL;
}
qemu_mutex_lock(&thr->mutex);
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;
}
break;
case CONNECT_THREAD_RUNNING_DETACHED:
do_free = true;
break;
default:
abort();
}
qemu_mutex_unlock(&thr->mutex);
if (do_free) {
nbd_free_connect_thread(thr);
}
return NULL;
}
static QIOChannelSocket *coroutine_fn
nbd_co_establish_connection(BlockDriverState *bs, Error **errp)
{
QemuThread thread;
BDRVNBDState *s = bs->opaque;
QIOChannelSocket *res;
NBDConnectThread *thr = s->connect_thread;
qemu_mutex_lock(&thr->mutex);
switch (thr->state) {
case CONNECT_THREAD_FAIL:
case CONNECT_THREAD_NONE:
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;
res = thr->sioc;
thr->sioc = NULL;
qemu_mutex_unlock(&thr->mutex);
return res;
case CONNECT_THREAD_RUNNING:
/* Already running, will wait */
break;
default:
abort();
}
thr->bh_ctx = qemu_get_current_aio_context();
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);
switch (thr->state) {
case CONNECT_THREAD_SUCCESS:
case CONNECT_THREAD_FAIL:
thr->state = CONNECT_THREAD_NONE;
error_propagate(errp, thr->err);
thr->err = NULL;
res = thr->sioc;
thr->sioc = NULL;
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.
*/
res = NULL;
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 res;
}
/*
* 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)
{
BDRVNBDState *s = bs->opaque;
NBDConnectThread *thr = s->connect_thread;
bool wake = false;
bool do_free = false;
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;
}
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);
}
}
static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s)
{
int ret;
Error *local_err = NULL;
QIOChannelSocket *sioc;
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;
}
sioc = nbd_co_establish_connection(s->bs, &local_err);
if (!sioc) {
ret = -ECONNREFUSED;
goto out;
}
bdrv_dec_in_flight(s->bs);
ret = nbd_client_handshake(s->bs, sioc, &local_err);
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();
}
}
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;
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);
}
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);
} else {
qemu_co_sleep_ns_wakeable(QEMU_CLOCK_REALTIME, timeout,
&s->connection_co_sleep_ns_state);
if (timeout < max_timeout) {
timeout *= 2;
}
}
nbd_reconnect_attempt(s);
}
}
static coroutine_fn void nbd_connection_entry(void *opaque)
{
BDRVNBDState *s = opaque;
uint64_t i;
int ret = 0;
Error *local_err = NULL;
while (s->state != NBD_CLIENT_QUIT) {
/*
* The NBD client can only really be considered idle when it has
* yielded from qio_channel_readv_all_eof(), waiting for data. This is
* the point where the additional scheduled coroutine entry happens
* after nbd_client_attach_aio_context().
*
* 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);
continue;
}
/*
* There's no need for a mutex on the receive side, because the
* handler acts as a synchronization point and ensures that only
* one coroutine is called until the reply finishes.
*/
i = HANDLE_TO_INDEX(s, s->reply.handle);
if (i >= MAX_NBD_REQUESTS ||
!s->requests[i].coroutine ||
!s->requests[i].receiving ||
(nbd_reply_is_structured(&s->reply) && !s->info.structured_reply))
{
nbd_channel_error(s, -EINVAL);
continue;
}
/*
* We're woken up again by the request itself. Note that there
* is no race between yielding and reentering connection_co. This
* is because:
*
* - if the request runs on the same AioContext, it is only
* entered after we yield
*
* - if the request runs on a different AioContext, reentering
* connection_co happens through a bottom half, which can only
* run after we yield.
*/
aio_co_wake(s->requests[i].coroutine);
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;
}
if (s->teardown_co) {
aio_co_wake(s->teardown_co);
}
aio_wait_kick();
}
static int nbd_co_send_request(BlockDriverState *bs,
NBDRequest *request,
QEMUIOVector *qiov)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
int rc, i = -1;
qemu_co_mutex_lock(&s->send_mutex);
while (s->in_flight == MAX_NBD_REQUESTS || nbd_client_connecting_wait(s)) {
qemu_co_queue_wait(&s->free_sema, &s->send_mutex);
}
if (s->state != NBD_CLIENT_CONNECTED) {
rc = -EIO;
goto err;
}
s->in_flight++;
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
if (s->requests[i].coroutine == NULL) {
break;
}
}
g_assert(qemu_in_coroutine());
assert(i < MAX_NBD_REQUESTS);
s->requests[i].coroutine = qemu_coroutine_self();
s->requests[i].offset = request->from;
s->requests[i].receiving = false;
request->handle = INDEX_TO_HANDLE(s, i);
assert(s->ioc);
if (qiov) {
qio_channel_set_cork(s->ioc, true);
rc = nbd_send_request(s->ioc, request);
if (rc >= 0 && s->state == NBD_CLIENT_CONNECTED) {
if (qio_channel_writev_all(s->ioc, qiov->iov, qiov->niov,
NULL) < 0) {
rc = -EIO;
}
} else if (rc >= 0) {
rc = -EIO;
}
qio_channel_set_cork(s->ioc, false);
} else {
rc = nbd_send_request(s->ioc, request);
}
err:
if (rc < 0) {
nbd_channel_error(s, rc);
if (i != -1) {
s->requests[i].coroutine = NULL;
s->in_flight--;
}
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;
}
static inline uint16_t payload_advance16(uint8_t **payload)
{
*payload += 2;
return lduw_be_p(*payload - 2);
}
static inline uint32_t payload_advance32(uint8_t **payload)
{
*payload += 4;
return ldl_be_p(*payload - 4);
}
static inline uint64_t payload_advance64(uint8_t **payload)
{
*payload += 8;
return ldq_be_p(*payload - 8);
}
static int nbd_parse_offset_hole_payload(BDRVNBDState *s,
NBDStructuredReplyChunk *chunk,
uint8_t *payload, uint64_t orig_offset,
QEMUIOVector *qiov, Error **errp)
{
uint64_t offset;
uint32_t hole_size;
if (chunk->length != sizeof(offset) + sizeof(hole_size)) {
error_setg(errp, "Protocol error: invalid payload for "
"NBD_REPLY_TYPE_OFFSET_HOLE");
return -EINVAL;
}
offset = payload_advance64(&payload);
hole_size = payload_advance32(&payload);
if (!hole_size || offset < orig_offset || hole_size > qiov->size ||
offset > orig_offset + qiov->size - hole_size) {
error_setg(errp, "Protocol error: server sent chunk exceeding requested"
" region");
return -EINVAL;
}
if (s->info.min_block &&
!QEMU_IS_ALIGNED(hole_size, s->info.min_block)) {
trace_nbd_structured_read_compliance("hole");
}
qemu_iovec_memset(qiov, offset - orig_offset, 0, hole_size);
return 0;
}
/*
* nbd_parse_blockstatus_payload
* Based on our request, we expect only one extent in reply, for the
* base:allocation context.
*/
static int nbd_parse_blockstatus_payload(BDRVNBDState *s,
NBDStructuredReplyChunk *chunk,
uint8_t *payload, uint64_t orig_length,
NBDExtent *extent, Error **errp)
{
uint32_t context_id;
/* The server succeeded, so it must have sent [at least] one extent */
if (chunk->length < sizeof(context_id) + sizeof(*extent)) {
error_setg(errp, "Protocol error: invalid payload for "
"NBD_REPLY_TYPE_BLOCK_STATUS");
return -EINVAL;
}
context_id = payload_advance32(&payload);
if (s->info.context_id != context_id) {
error_setg(errp, "Protocol error: unexpected context id %d for "
"NBD_REPLY_TYPE_BLOCK_STATUS, when negotiated context "
"id is %d", context_id,
s->info.context_id);
return -EINVAL;
}
extent->length = payload_advance32(&payload);
extent->flags = payload_advance32(&payload);
if (extent->length == 0) {
error_setg(errp, "Protocol error: server sent status chunk with "
"zero length");
return -EINVAL;
}
/*
* A server sending unaligned block status is in violation of the
* protocol, but as qemu-nbd 3.1 is such a server (at least for
* POSIX files that are not a multiple of 512 bytes, since qemu
* rounds files up to 512-byte multiples but lseek(SEEK_HOLE)
* still sees an implicit hole beyond the real EOF), it's nicer to
* work around the misbehaving server. If the request included
* more than the final unaligned block, truncate it back to an
* aligned result; if the request was only the final block, round
* up to the full block and change the status to fully-allocated
* (always a safe status, even if it loses information).
*/
if (s->info.min_block && !QEMU_IS_ALIGNED(extent->length,
s->info.min_block)) {
trace_nbd_parse_blockstatus_compliance("extent length is unaligned");
if (extent->length > s->info.min_block) {
extent->length = QEMU_ALIGN_DOWN(extent->length,
s->info.min_block);
} else {
extent->length = s->info.min_block;
extent->flags = 0;
}
}
/*
* We used NBD_CMD_FLAG_REQ_ONE, so the server should not have
* sent us any more than one extent, nor should it have included
* status beyond our request in that extent. However, it's easy
* enough to ignore the server's noncompliance without killing the
* connection; just ignore trailing extents, and clamp things to
* the length of our request.
*/
if (chunk->length > sizeof(context_id) + sizeof(*extent)) {
trace_nbd_parse_blockstatus_compliance("more than one extent");
}
if (extent->length > orig_length) {
extent->length = orig_length;
trace_nbd_parse_blockstatus_compliance("extent length too large");
}
return 0;
}
/*
* nbd_parse_error_payload
* on success @errp contains message describing nbd error reply
*/
static int nbd_parse_error_payload(NBDStructuredReplyChunk *chunk,
uint8_t *payload, int *request_ret,
Error **errp)
{
uint32_t error;
uint16_t message_size;
assert(chunk->type & (1 << 15));
if (chunk->length < sizeof(error) + sizeof(message_size)) {
error_setg(errp,
"Protocol error: invalid payload for structured error");
return -EINVAL;
}
error = nbd_errno_to_system_errno(payload_advance32(&payload));
if (error == 0) {
error_setg(errp, "Protocol error: server sent structured error chunk "
"with error = 0");
return -EINVAL;
}
*request_ret = -error;
message_size = payload_advance16(&payload);
if (message_size > chunk->length - sizeof(error) - sizeof(message_size)) {
error_setg(errp, "Protocol error: server sent structured error chunk "
"with incorrect message size");
return -EINVAL;
}
/* TODO: Add a trace point to mention the server complaint */
/* TODO handle ERROR_OFFSET */
return 0;
}
static int nbd_co_receive_offset_data_payload(BDRVNBDState *s,
uint64_t orig_offset,
QEMUIOVector *qiov, Error **errp)
{
QEMUIOVector sub_qiov;
uint64_t offset;
size_t data_size;
int ret;
NBDStructuredReplyChunk *chunk = &s->reply.structured;
assert(nbd_reply_is_structured(&s->reply));
/* The NBD spec requires at least one byte of payload */
if (chunk->length <= sizeof(offset)) {
error_setg(errp, "Protocol error: invalid payload for "
"NBD_REPLY_TYPE_OFFSET_DATA");
return -EINVAL;
}
if (nbd_read64(s->ioc, &offset, "OFFSET_DATA offset", errp) < 0) {
return -EIO;
}
data_size = chunk->length - sizeof(offset);
assert(data_size);
if (offset < orig_offset || data_size > qiov->size ||
offset > orig_offset + qiov->size - data_size) {
error_setg(errp, "Protocol error: server sent chunk exceeding requested"
" region");
return -EINVAL;
}
if (s->info.min_block && !QEMU_IS_ALIGNED(data_size, s->info.min_block)) {
trace_nbd_structured_read_compliance("data");
}
qemu_iovec_init(&sub_qiov, qiov->niov);
qemu_iovec_concat(&sub_qiov, qiov, offset - orig_offset, data_size);
ret = qio_channel_readv_all(s->ioc, sub_qiov.iov, sub_qiov.niov, errp);
qemu_iovec_destroy(&sub_qiov);
return ret < 0 ? -EIO : 0;
}
#define NBD_MAX_MALLOC_PAYLOAD 1000
static coroutine_fn int nbd_co_receive_structured_payload(
BDRVNBDState *s, void **payload, Error **errp)
{
int ret;
uint32_t len;
assert(nbd_reply_is_structured(&s->reply));
len = s->reply.structured.length;
if (len == 0) {
return 0;
}
if (payload == NULL) {
error_setg(errp, "Unexpected structured payload");
return -EINVAL;
}
if (len > NBD_MAX_MALLOC_PAYLOAD) {
error_setg(errp, "Payload too large");
return -EINVAL;
}
*payload = g_new(char, len);
ret = nbd_read(s->ioc, *payload, len, "structured payload", errp);
if (ret < 0) {
g_free(*payload);
*payload = NULL;
return ret;
}
return 0;
}
/*
* nbd_co_do_receive_one_chunk
* for simple reply:
* set request_ret to received reply error
* if qiov is not NULL: read payload to @qiov
* for structured reply chunk:
* if error chunk: read payload, set @request_ret, do not set @payload
* else if offset_data chunk: read payload data to @qiov, do not set @payload
* else: read payload to @payload
*
* If function fails, @errp contains corresponding error message, and the
* connection with the server is suspect. If it returns 0, then the
* transaction succeeded (although @request_ret may be a negative errno
* corresponding to the server's error reply), and errp is unchanged.
*/
static coroutine_fn int nbd_co_do_receive_one_chunk(
BDRVNBDState *s, uint64_t handle, bool only_structured,
int *request_ret, QEMUIOVector *qiov, void **payload, Error **errp)
{
int ret;
int i = HANDLE_TO_INDEX(s, handle);
void *local_payload = NULL;
NBDStructuredReplyChunk *chunk;
if (payload) {
*payload = NULL;
}
*request_ret = 0;
/* Wait until we're woken up by nbd_connection_entry. */
s->requests[i].receiving = true;
qemu_coroutine_yield();
s->requests[i].receiving = false;
if (s->state != NBD_CLIENT_CONNECTED) {
error_setg(errp, "Connection closed");
return -EIO;
}
assert(s->ioc);
assert(s->reply.handle == handle);
if (nbd_reply_is_simple(&s->reply)) {
if (only_structured) {
error_setg(errp, "Protocol error: simple reply when structured "
"reply chunk was expected");
return -EINVAL;
}
*request_ret = -nbd_errno_to_system_errno(s->reply.simple.error);
if (*request_ret < 0 || !qiov) {
return 0;
}
return qio_channel_readv_all(s->ioc, qiov->iov, qiov->niov,
errp) < 0 ? -EIO : 0;
}
/* handle structured reply chunk */
assert(s->info.structured_reply);
chunk = &s->reply.structured;
if (chunk->type == NBD_REPLY_TYPE_NONE) {
if (!(chunk->flags & NBD_REPLY_FLAG_DONE)) {
error_setg(errp, "Protocol error: NBD_REPLY_TYPE_NONE chunk without"
" NBD_REPLY_FLAG_DONE flag set");
return -EINVAL;
}
if (chunk->length) {
error_setg(errp, "Protocol error: NBD_REPLY_TYPE_NONE chunk with"
" nonzero length");
return -EINVAL;
}
return 0;
}
if (chunk->type == NBD_REPLY_TYPE_OFFSET_DATA) {
if (!qiov) {
error_setg(errp, "Unexpected NBD_REPLY_TYPE_OFFSET_DATA chunk");
return -EINVAL;
}
return nbd_co_receive_offset_data_payload(s, s->requests[i].offset,
qiov, errp);
}
if (nbd_reply_type_is_error(chunk->type)) {
payload = &local_payload;
}
ret = nbd_co_receive_structured_payload(s, payload, errp);
if (ret < 0) {
return ret;
}
if (nbd_reply_type_is_error(chunk->type)) {
ret = nbd_parse_error_payload(chunk, local_payload, request_ret, errp);
g_free(local_payload);
return ret;
}
return 0;
}
/*
* nbd_co_receive_one_chunk
* Read reply, wake up connection_co and set s->quit if needed.
* Return value is a fatal error code or normal nbd reply error code
*/
static coroutine_fn int nbd_co_receive_one_chunk(
BDRVNBDState *s, uint64_t handle, bool only_structured,
int *request_ret, QEMUIOVector *qiov, NBDReply *reply, void **payload,
Error **errp)
{
int ret = nbd_co_do_receive_one_chunk(s, handle, only_structured,
request_ret, qiov, payload, errp);
if (ret < 0) {
memset(reply, 0, sizeof(*reply));
nbd_channel_error(s, ret);
} else {
/* For assert at loop start in nbd_connection_entry */
*reply = s->reply;
}
s->reply.handle = 0;
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);
}
return ret;
}
typedef struct NBDReplyChunkIter {
int ret;
int request_ret;
Error *err;
bool done, only_structured;
} NBDReplyChunkIter;
static void nbd_iter_channel_error(NBDReplyChunkIter *iter,
int ret, Error **local_err)
{
assert(local_err && *local_err);
assert(ret < 0);
if (!iter->ret) {
iter->ret = ret;
error_propagate(&iter->err, *local_err);
} else {
error_free(*local_err);
}
*local_err = NULL;
}
static void nbd_iter_request_error(NBDReplyChunkIter *iter, int ret)
{
assert(ret < 0);
if (!iter->request_ret) {
iter->request_ret = ret;
}
}
/*
* NBD_FOREACH_REPLY_CHUNK
* The pointer stored in @payload requires g_free() to free it.
*/
#define NBD_FOREACH_REPLY_CHUNK(s, iter, handle, structured, \
qiov, reply, payload) \
for (iter = (NBDReplyChunkIter) { .only_structured = structured }; \
nbd_reply_chunk_iter_receive(s, &iter, handle, qiov, reply, payload);)
/*
* nbd_reply_chunk_iter_receive
* The pointer stored in @payload requires g_free() to free it.
*/
static bool nbd_reply_chunk_iter_receive(BDRVNBDState *s,
NBDReplyChunkIter *iter,
uint64_t handle,
QEMUIOVector *qiov, NBDReply *reply,
void **payload)
{
int ret, request_ret;
NBDReply local_reply;
NBDStructuredReplyChunk *chunk;
Error *local_err = NULL;
if (s->state != NBD_CLIENT_CONNECTED) {
error_setg(&local_err, "Connection closed");
nbd_iter_channel_error(iter, -EIO, &local_err);
goto break_loop;
}
if (iter->done) {
/* Previous iteration was last. */
goto break_loop;
}
if (reply == NULL) {
reply = &local_reply;
}
ret = nbd_co_receive_one_chunk(s, handle, iter->only_structured,
&request_ret, qiov, reply, payload,
&local_err);
if (ret < 0) {
nbd_iter_channel_error(iter, ret, &local_err);
} else if (request_ret < 0) {
nbd_iter_request_error(iter, request_ret);
}
/* Do not execute the body of NBD_FOREACH_REPLY_CHUNK for simple reply. */
if (nbd_reply_is_simple(reply) || s->state != NBD_CLIENT_CONNECTED) {
goto break_loop;
}
chunk = &reply->structured;
iter->only_structured = true;
if (chunk->type == NBD_REPLY_TYPE_NONE) {
/* NBD_REPLY_FLAG_DONE is already checked in nbd_co_receive_one_chunk */
assert(chunk->flags & NBD_REPLY_FLAG_DONE);
goto break_loop;
}
if (chunk->flags & NBD_REPLY_FLAG_DONE) {
/* This iteration is last. */
iter->done = true;
}
/* Execute the loop body */
return true;
break_loop:
s->requests[HANDLE_TO_INDEX(s, handle)].coroutine = NULL;
qemu_co_mutex_lock(&s->send_mutex);
s->in_flight--;
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;
}
static int nbd_co_receive_return_code(BDRVNBDState *s, uint64_t handle,
int *request_ret, Error **errp)
{
NBDReplyChunkIter iter;
NBD_FOREACH_REPLY_CHUNK(s, iter, handle, false, NULL, NULL, NULL) {
/* nbd_reply_chunk_iter_receive does all the work */
}
error_propagate(errp, iter.err);
*request_ret = iter.request_ret;
return iter.ret;
}
static int nbd_co_receive_cmdread_reply(BDRVNBDState *s, uint64_t handle,
uint64_t offset, QEMUIOVector *qiov,
int *request_ret, Error **errp)
{
NBDReplyChunkIter iter;
NBDReply reply;
void *payload = NULL;
Error *local_err = NULL;
NBD_FOREACH_REPLY_CHUNK(s, iter, handle, s->info.structured_reply,
qiov, &reply, &payload)
{
int ret;
NBDStructuredReplyChunk *chunk = &reply.structured;
assert(nbd_reply_is_structured(&reply));
switch (chunk->type) {
case NBD_REPLY_TYPE_OFFSET_DATA:
/*
* special cased in nbd_co_receive_one_chunk, data is already
* in qiov
*/
break;
case NBD_REPLY_TYPE_OFFSET_HOLE:
ret = nbd_parse_offset_hole_payload(s, &reply.structured, payload,
offset, qiov, &local_err);
if (ret < 0) {
nbd_channel_error(s, ret);
nbd_iter_channel_error(&iter, ret, &local_err);
}
break;
default:
if (!nbd_reply_type_is_error(chunk->type)) {
/* not allowed reply type */
nbd_channel_error(s, -EINVAL);
error_setg(&local_err,
"Unexpected reply type: %d (%s) for CMD_READ",
chunk->type, nbd_reply_type_lookup(chunk->type));
nbd_iter_channel_error(&iter, -EINVAL, &local_err);
}
}
g_free(payload);
payload = NULL;
}
error_propagate(errp, iter.err);
*request_ret = iter.request_ret;
return iter.ret;
}
static int nbd_co_receive_blockstatus_reply(BDRVNBDState *s,
uint64_t handle, uint64_t length,
NBDExtent *extent,
int *request_ret, Error **errp)
{
NBDReplyChunkIter iter;
NBDReply reply;
void *payload = NULL;
Error *local_err = NULL;
bool received = false;
assert(!extent->length);
NBD_FOREACH_REPLY_CHUNK(s, iter, handle, false, NULL, &reply, &payload) {
int ret;
NBDStructuredReplyChunk *chunk = &reply.structured;
assert(nbd_reply_is_structured(&reply));
switch (chunk->type) {
case NBD_REPLY_TYPE_BLOCK_STATUS:
if (received) {
nbd_channel_error(s, -EINVAL);
error_setg(&local_err, "Several BLOCK_STATUS chunks in reply");
nbd_iter_channel_error(&iter, -EINVAL, &local_err);
}
received = true;
ret = nbd_parse_blockstatus_payload(s, &reply.structured,
payload, length, extent,
&local_err);
if (ret < 0) {
nbd_channel_error(s, ret);
nbd_iter_channel_error(&iter, ret, &local_err);
}
break;
default:
if (!nbd_reply_type_is_error(chunk->type)) {
nbd_channel_error(s, -EINVAL);
error_setg(&local_err,
"Unexpected reply type: %d (%s) "
"for CMD_BLOCK_STATUS",
chunk->type, nbd_reply_type_lookup(chunk->type));
nbd_iter_channel_error(&iter, -EINVAL, &local_err);
}
}
g_free(payload);
payload = NULL;
}
if (!extent->length && !iter.request_ret) {
error_setg(&local_err, "Server did not reply with any status extents");
nbd_iter_channel_error(&iter, -EIO, &local_err);
}
error_propagate(errp, iter.err);
*request_ret = iter.request_ret;
return iter.ret;
}
static int nbd_co_request(BlockDriverState *bs, NBDRequest *request,
QEMUIOVector *write_qiov)
{
int ret, request_ret;
Error *local_err = NULL;
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
assert(request->type != NBD_CMD_READ);
if (write_qiov) {
assert(request->type == NBD_CMD_WRITE);
assert(request->len == iov_size(write_qiov->iov, write_qiov->niov));
} else {
assert(request->type != NBD_CMD_WRITE);
}
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;
}
static int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov, int flags)
{
int ret, request_ret;
Error *local_err = NULL;
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
NBDRequest request = {
.type = NBD_CMD_READ,
.from = offset,
.len = bytes,
};
assert(bytes <= NBD_MAX_BUFFER_SIZE);
assert(!flags);
if (!bytes) {
return 0;
}
/*
* Work around the fact that the block layer doesn't do
* byte-accurate sizing yet - if the read exceeds the server's
* advertised size because the block layer rounded size up, then
* truncate the request to the server and tail-pad with zero.
*/
if (offset >= s->info.size) {
assert(bytes < BDRV_SECTOR_SIZE);
qemu_iovec_memset(qiov, 0, 0, bytes);
return 0;
}
if (offset + bytes > s->info.size) {
uint64_t slop = offset + bytes - s->info.size;
assert(slop < BDRV_SECTOR_SIZE);
qemu_iovec_memset(qiov, bytes - slop, 0, slop);
request.len -= slop;
}
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));
return ret ? ret : request_ret;
}
static int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov, int flags)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
NBDRequest request = {
.type = NBD_CMD_WRITE,
.from = offset,
.len = bytes,
};
assert(!(s->info.flags & NBD_FLAG_READ_ONLY));
if (flags & BDRV_REQ_FUA) {
assert(s->info.flags & NBD_FLAG_SEND_FUA);
request.flags |= NBD_CMD_FLAG_FUA;
}
assert(bytes <= NBD_MAX_BUFFER_SIZE);
if (!bytes) {
return 0;
}
return nbd_co_request(bs, &request, qiov);
}
static int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
int bytes, BdrvRequestFlags flags)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
NBDRequest request = {
.type = NBD_CMD_WRITE_ZEROES,
.from = offset,
.len = bytes,
};
assert(!(s->info.flags & NBD_FLAG_READ_ONLY));
if (!(s->info.flags & NBD_FLAG_SEND_WRITE_ZEROES)) {
return -ENOTSUP;
}
if (flags & BDRV_REQ_FUA) {
assert(s->info.flags & NBD_FLAG_SEND_FUA);
request.flags |= NBD_CMD_FLAG_FUA;
}
if (!(flags & BDRV_REQ_MAY_UNMAP)) {
request.flags |= NBD_CMD_FLAG_NO_HOLE;
}
if (flags & BDRV_REQ_NO_FALLBACK) {
assert(s->info.flags & NBD_FLAG_SEND_FAST_ZERO);
request.flags |= NBD_CMD_FLAG_FAST_ZERO;
}
if (!bytes) {
return 0;
}
return nbd_co_request(bs, &request, NULL);
}
static int nbd_client_co_flush(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
NBDRequest request = { .type = NBD_CMD_FLUSH };
if (!(s->info.flags & NBD_FLAG_SEND_FLUSH)) {
return 0;
}
request.from = 0;
request.len = 0;
return nbd_co_request(bs, &request, NULL);
}
static int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset,
int bytes)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
NBDRequest request = {
.type = NBD_CMD_TRIM,
.from = offset,
.len = bytes,
};
assert(!(s->info.flags & NBD_FLAG_READ_ONLY));
if (!(s->info.flags & NBD_FLAG_SEND_TRIM) || !bytes) {
return 0;
}
return nbd_co_request(bs, &request, NULL);
}
static int coroutine_fn nbd_client_co_block_status(
BlockDriverState *bs, bool want_zero, int64_t offset, int64_t bytes,
int64_t *pnum, int64_t *map, BlockDriverState **file)
{
int ret, request_ret;
NBDExtent extent = { 0 };
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
Error *local_err = NULL;
NBDRequest request = {
.type = NBD_CMD_BLOCK_STATUS,
.from = offset,
.len = MIN(QEMU_ALIGN_DOWN(INT_MAX, bs->bl.request_alignment),
MIN(bytes, s->info.size - offset)),
.flags = NBD_CMD_FLAG_REQ_ONE,
};
if (!s->info.base_allocation) {
*pnum = bytes;
*map = offset;
*file = bs;
return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
}
/*
* Work around the fact that the block layer doesn't do
* byte-accurate sizing yet - if the status request exceeds the
* server's advertised size because the block layer rounded size
* up, we truncated the request to the server (above), or are
* called on just the hole.
*/
if (offset >= s->info.size) {
*pnum = bytes;
assert(bytes < BDRV_SECTOR_SIZE);
/* Intentionally don't report offset_valid for the hole */
return BDRV_BLOCK_ZERO;
}
if (s->info.min_block) {
assert(QEMU_IS_ALIGNED(request.len, s->info.min_block));
}
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));
if (ret < 0 || request_ret < 0) {
return ret ? ret : request_ret;
}
assert(extent.length);
*pnum = extent.length;
*map = offset;
*file = bs;
return (extent.flags & NBD_STATE_HOLE ? 0 : BDRV_BLOCK_DATA) |
(extent.flags & NBD_STATE_ZERO ? BDRV_BLOCK_ZERO : 0) |
BDRV_BLOCK_OFFSET_VALID;
}
static int nbd_client_reopen_prepare(BDRVReopenState *state,
BlockReopenQueue *queue, Error **errp)
{
BDRVNBDState *s = (BDRVNBDState *)state->bs->opaque;
if ((state->flags & BDRV_O_RDWR) && (s->info.flags & NBD_FLAG_READ_ONLY)) {
error_setg(errp, "Can't reopen read-only NBD mount as read/write");
return -EACCES;
}
return 0;
}
static void nbd_client_close(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
NBDRequest request = { .type = NBD_CMD_DISC };
if (s->ioc) {
nbd_send_request(s->ioc, &request);
}
nbd_teardown_connection(bs);
}
static QIOChannelSocket *nbd_establish_connection(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;
}
qio_channel_set_delay(QIO_CHANNEL(sioc), false);
return sioc;
}
/* nbd_client_handshake takes ownership on sioc. On failure it is unref'ed. */
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);
s->sioc = sioc;
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) {
object_unref(OBJECT(sioc));
s->sioc = NULL;
return ret;
}
if (s->x_dirty_bitmap && !s->info.base_allocation) {
error_setg(errp, "requested x-dirty-bitmap %s not found",
s->x_dirty_bitmap);
ret = -EINVAL;
goto fail;
}
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(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.
*/
{
NBDRequest request = { .type = NBD_CMD_DISC };
nbd_send_request(s->ioc ?: QIO_CHANNEL(sioc), &request);
object_unref(OBJECT(sioc));
s->sioc = NULL;
return ret;
}
}
/*
* Parse nbd_open options
*/
static int nbd_parse_uri(const char *filename, QDict *options)
{
URI *uri;
const char *p;
QueryParams *qp = NULL;
int ret = 0;
bool is_unix;
uri = uri_parse(filename);
if (!uri) {
return -EINVAL;
}
/* transport */
if (!g_strcmp0(uri->scheme, "nbd")) {
is_unix = false;
} else if (!g_strcmp0(uri->scheme, "nbd+tcp")) {
is_unix = false;
} else if (!g_strcmp0(uri->scheme, "nbd+unix")) {
is_unix = true;
} else {
ret = -EINVAL;
goto out;
}
p = uri->path ? uri->path : "";
if (p[0] == '/') {
p++;
}
if (p[0]) {
qdict_put_str(options, "export", p);
}
qp = query_params_parse(uri->query);
if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
ret = -EINVAL;
goto out;
}
if (is_unix) {
/* nbd+unix:///export?socket=path */
if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
ret = -EINVAL;
goto out;
}
qdict_put_str(options, "server.type", "unix");
qdict_put_str(options, "server.path", qp->p[0].value);
} else {
QString *host;
char *port_str;
/* nbd[+tcp]://host[:port]/export */
if (!uri->server) {
ret = -EINVAL;
goto out;
}
/* strip braces from literal IPv6 address */
if (uri->server[0] == '[') {
host = qstring_from_substr(uri->server, 1,
strlen(uri->server) - 1);
} else {
host = qstring_from_str(uri->server);
}
qdict_put_str(options, "server.type", "inet");
qdict_put(options, "server.host", host);
port_str = g_strdup_printf("%d", uri->port ?: NBD_DEFAULT_PORT);
qdict_put_str(options, "server.port", port_str);
g_free(port_str);
}
out:
if (qp) {
query_params_free(qp);
}
uri_free(uri);
return ret;
}
static bool nbd_has_filename_options_conflict(QDict *options, Error **errp)
{
const QDictEntry *e;
for (e = qdict_first(options); e; e = qdict_next(options, e)) {
if (!strcmp(e->key, "host") ||
!strcmp(e->key, "port") ||
!strcmp(e->key, "path") ||
!strcmp(e->key, "export") ||
strstart(e->key, "server.", NULL))
{
error_setg(errp, "Option '%s' cannot be used with a file name",
e->key);
return true;
}
}
return false;
}
static void nbd_parse_filename(const char *filename, QDict *options,
Error **errp)
{
g_autofree char *file = NULL;
char *export_name;
const char *host_spec;
const char *unixpath;
if (nbd_has_filename_options_conflict(options, errp)) {
return;
}
if (strstr(filename, "://")) {
int ret = nbd_parse_uri(filename, options);
if (ret < 0) {
error_setg(errp, "No valid URL specified");
}
return;
}
file = g_strdup(filename);
export_name = strstr(file, EN_OPTSTR);
if (export_name) {
if (export_name[strlen(EN_OPTSTR)] == 0) {
return;
}
export_name[0] = 0; /* truncate 'file' */
export_name += strlen(EN_OPTSTR);
qdict_put_str(options, "export", export_name);
}
/* extract the host_spec - fail if it's not nbd:... */
if (!strstart(file, "nbd:", &host_spec)) {
error_setg(errp, "File name string for NBD must start with 'nbd:'");
return;
}
if (!*host_spec) {
return;
}
/* are we a UNIX or TCP socket? */
if (strstart(host_spec, "unix:", &unixpath)) {
qdict_put_str(options, "server.type", "unix");
qdict_put_str(options, "server.path", unixpath);
} else {
InetSocketAddress *addr = g_new(InetSocketAddress, 1);
if (inet_parse(addr, host_spec, errp)) {
goto out_inet;
}
qdict_put_str(options, "server.type", "inet");
qdict_put_str(options, "server.host", addr->host);
qdict_put_str(options, "server.port", addr->port);
out_inet:
qapi_free_InetSocketAddress(addr);
}
}
static bool nbd_process_legacy_socket_options(QDict *output_options,
QemuOpts *legacy_opts,
Error **errp)
{
const char *path = qemu_opt_get(legacy_opts, "path");
const char *host = qemu_opt_get(legacy_opts, "host");
const char *port = qemu_opt_get(legacy_opts, "port");
const QDictEntry *e;
if (!path && !host && !port) {
return true;
}
for (e = qdict_first(output_options); e; e = qdict_next(output_options, e))
{
if (strstart(e->key, "server.", NULL)) {
error_setg(errp, "Cannot use 'server' and path/host/port at the "
"same time");
return false;
}
}
if (path && host) {
error_setg(errp, "path and host may not be used at the same time");
return false;
} else if (path) {
if (port) {
error_setg(errp, "port may not be used without host");
return false;
}
qdict_put_str(output_options, "server.type", "unix");
qdict_put_str(output_options, "server.path", path);
} else if (host) {
qdict_put_str(output_options, "server.type", "inet");
qdict_put_str(output_options, "server.host", host);
qdict_put_str(output_options, "server.port",
port ?: stringify(NBD_DEFAULT_PORT));
}
return true;
}
static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
Error **errp)
{
SocketAddress *saddr = NULL;
QDict *addr = NULL;
Visitor *iv = NULL;
qdict_extract_subqdict(options, &addr, "server.");
if (!qdict_size(addr)) {
error_setg(errp, "NBD server address missing");
goto done;
}
iv = qobject_input_visitor_new_flat_confused(addr, errp);
if (!iv) {
goto done;
}
if (!visit_type_SocketAddress(iv, NULL, &saddr, errp)) {
goto done;
}
done:
qobject_unref(addr);
visit_free(iv);
return saddr;
}
static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
{
Object *obj;
QCryptoTLSCreds *creds;
obj = object_resolve_path_component(
object_get_objects_root(), id);
if (!obj) {
error_setg(errp, "No TLS credentials with id '%s'",
id);
return NULL;
}
creds = (QCryptoTLSCreds *)
object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
if (!creds) {
error_setg(errp, "Object with id '%s' is not TLS credentials",
id);
return NULL;
}
if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
error_setg(errp,
"Expecting TLS credentials with a client endpoint");
return NULL;
}
object_ref(obj);
return creds;
}
static QemuOptsList nbd_runtime_opts = {
.name = "nbd",
.head = QTAILQ_HEAD_INITIALIZER(nbd_runtime_opts.head),
.desc = {
{
.name = "host",
.type = QEMU_OPT_STRING,
.help = "TCP host to connect to",
},
{
.name = "port",
.type = QEMU_OPT_STRING,
.help = "TCP port to connect to",
},
{
.name = "path",
.type = QEMU_OPT_STRING,
.help = "Unix socket path to connect to",
},
{
.name = "export",
.type = QEMU_OPT_STRING,
.help = "Name of the NBD export to open",
},
{
.name = "tls-creds",
.type = QEMU_OPT_STRING,
.help = "ID of the TLS credentials to use",
},
{
.name = "x-dirty-bitmap",
.type = QEMU_OPT_STRING,
.help = "experimental: expose named dirty bitmap in place of "
"block status",
},
{
.name = "reconnect-delay",
.type = QEMU_OPT_NUMBER,
.help = "On an unexpected disconnect, the nbd client tries to "
"connect again until succeeding or encountering a serious "
"error. During the first @reconnect-delay seconds, all "
"requests are paused and will be rerun on a successful "
"reconnect. After that time, any delayed requests and all "
"future requests before a successful reconnect will "
"immediately fail. Default 0",
},
{ /* end of list */ }
},
};
static int nbd_process_options(BlockDriverState *bs, QDict *options,
Error **errp)
{
BDRVNBDState *s = bs->opaque;
QemuOpts *opts;
int ret = -EINVAL;
opts = qemu_opts_create(&nbd_runtime_opts, NULL, 0, &error_abort);
if (!qemu_opts_absorb_qdict(opts, options, errp)) {
goto error;
}
/* Translate @host, @port, and @path to a SocketAddress */
if (!nbd_process_legacy_socket_options(options, opts, errp)) {
goto error;
}
/* Pop the config into our state object. Exit if invalid. */
s->saddr = nbd_config(s, options, errp);
if (!s->saddr) {
goto error;
}
s->export = g_strdup(qemu_opt_get(opts, "export"));
if (s->export && strlen(s->export) > NBD_MAX_STRING_SIZE) {
error_setg(errp, "export name too long to send to server");
goto error;
}
s->tlscredsid = g_strdup(qemu_opt_get(opts, "tls-creds"));
if (s->tlscredsid) {
s->tlscreds = nbd_get_tls_creds(s->tlscredsid, errp);
if (!s->tlscreds) {
goto error;
}
/* TODO SOCKET_ADDRESS_KIND_FD where fd has AF_INET or AF_INET6 */
if (s->saddr->type != SOCKET_ADDRESS_TYPE_INET) {
error_setg(errp, "TLS only supported over IP sockets");
goto error;
}
s->hostname = s->saddr->u.inet.host;
}
s->x_dirty_bitmap = g_strdup(qemu_opt_get(opts, "x-dirty-bitmap"));
if (s->x_dirty_bitmap && strlen(s->x_dirty_bitmap) > NBD_MAX_STRING_SIZE) {
error_setg(errp, "x-dirty-bitmap query too long to send to server");
goto error;
}
s->reconnect_delay = qemu_opt_get_number(opts, "reconnect-delay", 0);
ret = 0;
error:
if (ret < 0) {
nbd_clear_bdrvstate(s);
}
qemu_opts_del(opts);
return ret;
}
static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
int ret;
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
QIOChannelSocket *sioc;
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);
/*
* establish TCP connection, return error if it fails
* TODO: Configurable retry-until-timeout behaviour.
*/
sioc = nbd_establish_connection(s->saddr, errp);
if (!sioc) {
return -ECONNREFUSED;
}
ret = nbd_client_handshake(bs, sioc, errp);
if (ret < 0) {
nbd_clear_bdrvstate(s);
return ret;
}
/* 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);
return 0;
}
static int nbd_co_flush(BlockDriverState *bs)
{
return nbd_client_co_flush(bs);
}
static void nbd_refresh_limits(BlockDriverState *bs, Error **errp)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
uint32_t min = s->info.min_block;
uint32_t max = MIN_NON_ZERO(NBD_MAX_BUFFER_SIZE, s->info.max_block);
/*
* If the server did not advertise an alignment:
* - a size that is not sector-aligned implies that an alignment
* of 1 can be used to access those tail bytes
* - advertisement of block status requires an alignment of 1, so
* that we don't violate block layer constraints that block
* status is always aligned (as we can't control whether the
* server will report sub-sector extents, such as a hole at EOF
* on an unaligned POSIX file)
* - otherwise, assume the server is so old that we are safer avoiding
* sub-sector requests
*/
if (!min) {
min = (!QEMU_IS_ALIGNED(s->info.size, BDRV_SECTOR_SIZE) ||
s->info.base_allocation) ? 1 : BDRV_SECTOR_SIZE;
}
bs->bl.request_alignment = min;
bs->bl.max_pdiscard = QEMU_ALIGN_DOWN(INT_MAX, min);
bs->bl.max_pwrite_zeroes = max;
bs->bl.max_transfer = max;
if (s->info.opt_block &&
s->info.opt_block > bs->bl.opt_transfer) {
bs->bl.opt_transfer = s->info.opt_block;
}
}
static void nbd_close(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
nbd_client_close(bs);
nbd_clear_bdrvstate(s);
}
/*
* NBD cannot truncate, but if the caller asks to truncate to the same size, or
* to a smaller size with exact=false, there is no reason to fail the
* operation.
*
* Preallocation mode is ignored since it does not seems useful to fail when
* we never change anything.
*/
static int coroutine_fn nbd_co_truncate(BlockDriverState *bs, int64_t offset,
bool exact, PreallocMode prealloc,
BdrvRequestFlags flags, Error **errp)
{
BDRVNBDState *s = bs->opaque;
if (offset != s->info.size && exact) {
error_setg(errp, "Cannot resize NBD nodes");
return -ENOTSUP;
}
if (offset > s->info.size) {
error_setg(errp, "Cannot grow NBD nodes");
return -EINVAL;
}
return 0;
}
static int64_t nbd_getlength(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
return s->info.size;
}
static void nbd_refresh_filename(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
const char *host = NULL, *port = NULL, *path = NULL;
size_t len = 0;
if (s->saddr->type == SOCKET_ADDRESS_TYPE_INET) {
const InetSocketAddress *inet = &s->saddr->u.inet;
if (!inet->has_ipv4 && !inet->has_ipv6 && !inet->has_to) {
host = inet->host;
port = inet->port;
}
} else if (s->saddr->type == SOCKET_ADDRESS_TYPE_UNIX) {
path = s->saddr->u.q_unix.path;
} /* else can't represent as pseudo-filename */
if (path && s->export) {
len = snprintf(bs->exact_filename, sizeof(bs->exact_filename),
"nbd+unix:///%s?socket=%s", s->export, path);
} else if (path && !s->export) {
len = snprintf(bs->exact_filename, sizeof(bs->exact_filename),
"nbd+unix://?socket=%s", path);
} else if (host && s->export) {
len = snprintf(bs->exact_filename, sizeof(bs->exact_filename),
"nbd://%s:%s/%s", host, port, s->export);
} else if (host && !s->export) {
len = snprintf(bs->exact_filename, sizeof(bs->exact_filename),
"nbd://%s:%s", host, port);
}
if (len >= sizeof(bs->exact_filename)) {
/* Name is too long to represent exactly, so leave it empty. */
bs->exact_filename[0] = '\0';
}
}
static char *nbd_dirname(BlockDriverState *bs, Error **errp)
{
/* The generic bdrv_dirname() implementation is able to work out some
* directory name for NBD nodes, but that would be wrong. So far there is no
* specification for how "export paths" would work, so NBD does not have
* directory names. */
error_setg(errp, "Cannot generate a base directory for NBD nodes");
return NULL;
}
static const char *const nbd_strong_runtime_opts[] = {
"path",
"host",
"port",
"export",
"tls-creds",
"server.",
NULL
};
static BlockDriver bdrv_nbd = {
.format_name = "nbd",
.protocol_name = "nbd",
.instance_size = sizeof(BDRVNBDState),
.bdrv_parse_filename = nbd_parse_filename,
.bdrv_co_create_opts = bdrv_co_create_opts_simple,
.create_opts = &bdrv_create_opts_simple,
.bdrv_file_open = nbd_open,
.bdrv_reopen_prepare = nbd_client_reopen_prepare,
.bdrv_co_preadv = nbd_client_co_preadv,
.bdrv_co_pwritev = nbd_client_co_pwritev,
.bdrv_co_pwrite_zeroes = nbd_client_co_pwrite_zeroes,
.bdrv_close = nbd_close,
.bdrv_co_flush_to_os = nbd_co_flush,
.bdrv_co_pdiscard = nbd_client_co_pdiscard,
.bdrv_refresh_limits = nbd_refresh_limits,
.bdrv_co_truncate = nbd_co_truncate,
.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,
.strong_runtime_opts = nbd_strong_runtime_opts,
};
static BlockDriver bdrv_nbd_tcp = {
.format_name = "nbd",
.protocol_name = "nbd+tcp",
.instance_size = sizeof(BDRVNBDState),
.bdrv_parse_filename = nbd_parse_filename,
.bdrv_co_create_opts = bdrv_co_create_opts_simple,
.create_opts = &bdrv_create_opts_simple,
.bdrv_file_open = nbd_open,
.bdrv_reopen_prepare = nbd_client_reopen_prepare,
.bdrv_co_preadv = nbd_client_co_preadv,
.bdrv_co_pwritev = nbd_client_co_pwritev,
.bdrv_co_pwrite_zeroes = nbd_client_co_pwrite_zeroes,
.bdrv_close = nbd_close,
.bdrv_co_flush_to_os = nbd_co_flush,
.bdrv_co_pdiscard = nbd_client_co_pdiscard,
.bdrv_refresh_limits = nbd_refresh_limits,
.bdrv_co_truncate = nbd_co_truncate,
.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,
.strong_runtime_opts = nbd_strong_runtime_opts,
};
static BlockDriver bdrv_nbd_unix = {
.format_name = "nbd",
.protocol_name = "nbd+unix",
.instance_size = sizeof(BDRVNBDState),
.bdrv_parse_filename = nbd_parse_filename,
.bdrv_co_create_opts = bdrv_co_create_opts_simple,
.create_opts = &bdrv_create_opts_simple,
.bdrv_file_open = nbd_open,
.bdrv_reopen_prepare = nbd_client_reopen_prepare,
.bdrv_co_preadv = nbd_client_co_preadv,
.bdrv_co_pwritev = nbd_client_co_pwritev,
.bdrv_co_pwrite_zeroes = nbd_client_co_pwrite_zeroes,
.bdrv_close = nbd_close,
.bdrv_co_flush_to_os = nbd_co_flush,
.bdrv_co_pdiscard = nbd_client_co_pdiscard,
.bdrv_refresh_limits = nbd_refresh_limits,
.bdrv_co_truncate = nbd_co_truncate,
.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,
.strong_runtime_opts = nbd_strong_runtime_opts,
};
static void bdrv_nbd_init(void)
{
bdrv_register(&bdrv_nbd);
bdrv_register(&bdrv_nbd_tcp);
bdrv_register(&bdrv_nbd_unix);
}
block_init(bdrv_nbd_init);
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