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qemu/block/nbd.c
Roman Kagan ddde5ee769 block/nbd: only enter connection coroutine if it's present 
When an NBD block driver state is moved from one aio_context to another
(e.g. when doing a drain in a migration thread),
nbd_client_attach_aio_context_bh is executed that enters the connection
coroutine.

However, the assumption that ->connection_co is always present here
appears incorrect: the connection may have encountered an error other
than -EIO in the underlying transport, and thus may have decided to quit
rather than keep trying to reconnect, and therefore it may have
terminated the connection coroutine.  As a result an attempt to reassign
the client in this state (NBD_CLIENT_QUIT) to a different aio_context
leads to a null pointer dereference:

  #0  qio_channel_detach_aio_context (ioc=0x0)
      at /build/qemu-gYtjVn/qemu-5.0.1/io/channel.c:452
  #1  0x0000562a242824b3 in bdrv_detach_aio_context (bs=0x562a268d6a00)
      at /build/qemu-gYtjVn/qemu-5.0.1/block.c:6151
  #2  bdrv_set_aio_context_ignore (bs=bs@entry=0x562a268d6a00,
      new_context=new_context@entry=0x562a260c9580,
      ignore=ignore@entry=0x7feeadc9b780)
      at /build/qemu-gYtjVn/qemu-5.0.1/block.c:6230
  #3  0x0000562a24282969 in bdrv_child_try_set_aio_context
      (bs=bs@entry=0x562a268d6a00, ctx=0x562a260c9580,
      ignore_child=<optimized out>, errp=<optimized out>)
      at /build/qemu-gYtjVn/qemu-5.0.1/block.c:6332
  #4  0x0000562a242bb7db in blk_do_set_aio_context (blk=0x562a2735d0d0,
      new_context=0x562a260c9580,
      update_root_node=update_root_node@entry=true, errp=errp@entry=0x0)
      at /build/qemu-gYtjVn/qemu-5.0.1/block/block-backend.c:1989
  #5  0x0000562a242be0bd in blk_set_aio_context (blk=<optimized out>,
      new_context=<optimized out>, errp=errp@entry=0x0)
      at /build/qemu-gYtjVn/qemu-5.0.1/block/block-backend.c:2010
  #6  0x0000562a23fbd953 in virtio_blk_data_plane_stop (vdev=<optimized
      out>)
      at /build/qemu-gYtjVn/qemu-5.0.1/hw/block/dataplane/virtio-blk.c:292
  #7  0x0000562a241fc7bf in virtio_bus_stop_ioeventfd (bus=0x562a260dbf08)
      at /build/qemu-gYtjVn/qemu-5.0.1/hw/virtio/virtio-bus.c:245
  #8  0x0000562a23fefb2e in virtio_vmstate_change (opaque=0x562a260dbf90,
      running=0, state=<optimized out>)
      at /build/qemu-gYtjVn/qemu-5.0.1/hw/virtio/virtio.c:3220
  #9  0x0000562a2402ebfd in vm_state_notify (running=running@entry=0,
      state=state@entry=RUN_STATE_FINISH_MIGRATE)
      at /build/qemu-gYtjVn/qemu-5.0.1/softmmu/vl.c:1275
  #10 0x0000562a23f7bc02 in do_vm_stop (state=RUN_STATE_FINISH_MIGRATE,
      send_stop=<optimized out>)
      at /build/qemu-gYtjVn/qemu-5.0.1/cpus.c:1032
  #11 0x0000562a24209765 in migration_completion (s=0x562a260e83a0)
      at /build/qemu-gYtjVn/qemu-5.0.1/migration/migration.c:2914
  #12 migration_iteration_run (s=0x562a260e83a0)
      at /build/qemu-gYtjVn/qemu-5.0.1/migration/migration.c:3275
  #13 migration_thread (opaque=opaque@entry=0x562a260e83a0)
      at /build/qemu-gYtjVn/qemu-5.0.1/migration/migration.c:3439
  #14 0x0000562a2435ca96 in qemu_thread_start (args=<optimized out>)
      at /build/qemu-gYtjVn/qemu-5.0.1/util/qemu-thread-posix.c:519
  #15 0x00007feed31466ba in start_thread (arg=0x7feeadc9c700)
      at pthread_create.c:333
  #16 0x00007feed2e7c41d in __GI___sysctl (name=0x0, nlen=608471908,
      oldval=0x562a2452b138, oldlenp=0x0, newval=0x562a2452c5e0
      <__func__.28102>, newlen=0)
      at ../sysdeps/unix/sysv/linux/sysctl.c:30
  #17 0x0000000000000000 in ?? ()

Fix it by checking that the connection coroutine is non-null before
trying to enter it.  If it is null, no entering is needed, as the
connection is probably going down anyway.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210129073859.683063-3-rvkagan@yandex-team.ru>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-02-03 08:17:12 -06:00

2553 lines
77 KiB
C
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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 "qemu/atomic.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"
#include "qemu/yank.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;
QEMUTimer *reconnect_delay_timer;
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 alloc_depth;
bool wait_connect;
NBDConnectThread *connect_thread;
} BDRVNBDState;
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 int nbd_client_handshake(BlockDriverState *bs, Error **errp);
static void nbd_yank(void *opaque);
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 (qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTED) {
s->state = s->reconnect_delay ? NBD_CLIENT_CONNECTING_WAIT :
NBD_CLIENT_CONNECTING_NOWAIT;
}
} else {
if (qatomic_load_acquire(&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 reconnect_delay_timer_del(BDRVNBDState *s)
{
if (s->reconnect_delay_timer) {
timer_free(s->reconnect_delay_timer);
s->reconnect_delay_timer = NULL;
}
}
static void reconnect_delay_timer_cb(void *opaque)
{
BDRVNBDState *s = opaque;
if (qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTING_WAIT) {
s->state = NBD_CLIENT_CONNECTING_NOWAIT;
while (qemu_co_enter_next(&s->free_sema, NULL)) {
/* Resume all queued requests */
}
}
reconnect_delay_timer_del(s);
}
static void reconnect_delay_timer_init(BDRVNBDState *s, uint64_t expire_time_ns)
{
if (qatomic_load_acquire(&s->state) != NBD_CLIENT_CONNECTING_WAIT) {
return;
}
assert(!s->reconnect_delay_timer);
s->reconnect_delay_timer = aio_timer_new(bdrv_get_aio_context(s->bs),
QEMU_CLOCK_REALTIME,
SCALE_NS,
reconnect_delay_timer_cb, s);
timer_mod(s->reconnect_delay_timer, expire_time_ns);
}
static void nbd_client_detach_aio_context(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
/* Timer is deleted in nbd_client_co_drain_begin() */
assert(!s->reconnect_delay_timer);
/*
* If reconnect is in progress we may have no ->ioc. It will be
* re-instantiated in the proper aio context once the connection is
* reestablished.
*/
if (s->ioc) {
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;
if (s->connection_co) {
/*
* 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 (qatomic_load_acquire(&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);
reconnect_delay_timer_del(s);
if (qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTING_WAIT) {
s->state = NBD_CLIENT_CONNECTING_NOWAIT;
qemu_co_queue_restart_all(&s->free_sema);
}
}
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)
{
NBDClientState state = qatomic_load_acquire(&s->state);
return state == NBD_CLIENT_CONNECTING_WAIT ||
state == NBD_CLIENT_CONNECTING_NOWAIT;
}
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);
*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 int coroutine_fn
nbd_co_establish_connection(BlockDriverState *bs, Error **errp)
{
int ret;
QemuThread thread;
BDRVNBDState *s = bs->opaque;
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;
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->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;
s->sioc = thr->sioc;
thr->sioc = NULL;
if (s->sioc) {
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;
}
/*
* 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;
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) {
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;
}
if (nbd_co_establish_connection(s->bs, &local_err) < 0) {
ret = -ECONNREFUSED;
goto out;
}
bdrv_dec_in_flight(s->bs);
ret = nbd_client_handshake(s->bs, &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 timeout = 1 * NANOSECONDS_PER_SECOND;
uint64_t max_timeout = 16 * NANOSECONDS_PER_SECOND;
if (qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTING_WAIT) {
reconnect_delay_timer_init(s, qemu_clock_get_ns(QEMU_CLOCK_REALTIME) +
s->reconnect_delay * NANOSECONDS_PER_SECOND);
}
nbd_reconnect_attempt(s);
while (nbd_client_connecting(s)) {
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 (s->drained) {
continue;
}
if (timeout < max_timeout) {
timeout *= 2;
}
}
nbd_reconnect_attempt(s);
}
reconnect_delay_timer_del(s);
}
static coroutine_fn void nbd_connection_entry(void *opaque)
{
BDRVNBDState *s = opaque;
uint64_t i;
int ret = 0;
Error *local_err = NULL;
while (qatomic_load_acquire(&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 (qatomic_load_acquire(&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) {
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;
}
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 (qatomic_load_acquire(&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 (qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTED &&
rc >= 0) {
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");
}
/*
* HACK: if we are using x-dirty-bitmaps to access
* qemu:allocation-depth, treat all depths > 2 the same as 2,
* since nbd_client_co_block_status is only expecting the low two
* bits to be set.
*/
if (s->alloc_depth && extent->flags > 2) {
extent->flags = 2;
}
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 (qatomic_load_acquire(&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 (qatomic_load_acquire(&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) ||
qatomic_load_acquire(&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_yank(void *opaque)
{
BlockDriverState *bs = 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);
}
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 int nbd_establish_connection(BlockDriverState *bs,
SocketAddress *saddr,
Error **errp)
{
ERRP_GUARD();
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
s->sioc = qio_channel_socket_new();
qio_channel_set_name(QIO_CHANNEL(s->sioc), "nbd-client");
qio_channel_socket_connect_sync(s->sioc, saddr, errp);
if (*errp) {
object_unref(OBJECT(s->sioc));
s->sioc = NULL;
return -1;
}
yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), nbd_yank, bs);
qio_channel_set_delay(QIO_CHANNEL(s->sioc), false);
return 0;
}
/* nbd_client_handshake takes ownership on s->sioc. On failure it's unref'ed. */
static int nbd_client_handshake(BlockDriverState *bs, 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);
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,
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;
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.
*/
{
NBDRequest request = { .type = NBD_CMD_DISC };
nbd_send_request(s->ioc ?: QIO_CHANNEL(s->sioc), &request);
yank_unregister_function(BLOCKDEV_YANK_INSTANCE(bs->node_name),
nbd_yank, bs);
object_unref(OBJECT(s->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;
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);
if (!yank_register_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name), errp)) {
return -EEXIST;
}
/*
* 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 = nbd_client_handshake(bs, errp);
if (ret < 0) {
yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name));
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);
yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name));
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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