Now that all callers are converted to use I/O channels for initial connection setup, it is possible to switch the core NBD protocol handling core over to use QIOChannel APIs for actual sockets I/O. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1455129674-17255-7-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
430 lines
12 KiB
C
430 lines
12 KiB
C
/*
|
|
* QEMU Block driver for NBD
|
|
*
|
|
* 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 "nbd-client.h"
|
|
|
|
#define HANDLE_TO_INDEX(bs, handle) ((handle) ^ ((uint64_t)(intptr_t)bs))
|
|
#define INDEX_TO_HANDLE(bs, index) ((index) ^ ((uint64_t)(intptr_t)bs))
|
|
|
|
static void nbd_recv_coroutines_enter_all(NbdClientSession *s)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
|
|
if (s->recv_coroutine[i]) {
|
|
qemu_coroutine_enter(s->recv_coroutine[i], NULL);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void nbd_teardown_connection(BlockDriverState *bs)
|
|
{
|
|
NbdClientSession *client = nbd_get_client_session(bs);
|
|
|
|
if (!client->ioc) { /* Already closed */
|
|
return;
|
|
}
|
|
|
|
/* finish any pending coroutines */
|
|
qio_channel_shutdown(client->ioc,
|
|
QIO_CHANNEL_SHUTDOWN_BOTH,
|
|
NULL);
|
|
nbd_recv_coroutines_enter_all(client);
|
|
|
|
nbd_client_detach_aio_context(bs);
|
|
object_unref(OBJECT(client->sioc));
|
|
client->sioc = NULL;
|
|
object_unref(OBJECT(client->ioc));
|
|
client->ioc = NULL;
|
|
}
|
|
|
|
static void nbd_reply_ready(void *opaque)
|
|
{
|
|
BlockDriverState *bs = opaque;
|
|
NbdClientSession *s = nbd_get_client_session(bs);
|
|
uint64_t i;
|
|
int ret;
|
|
|
|
if (!s->ioc) { /* Already closed */
|
|
return;
|
|
}
|
|
|
|
if (s->reply.handle == 0) {
|
|
/* No reply already in flight. Fetch a header. It is possible
|
|
* that another thread has done the same thing in parallel, so
|
|
* the socket is not readable anymore.
|
|
*/
|
|
ret = nbd_receive_reply(s->ioc, &s->reply);
|
|
if (ret == -EAGAIN) {
|
|
return;
|
|
}
|
|
if (ret < 0) {
|
|
s->reply.handle = 0;
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
/* 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) {
|
|
goto fail;
|
|
}
|
|
|
|
if (s->recv_coroutine[i]) {
|
|
qemu_coroutine_enter(s->recv_coroutine[i], NULL);
|
|
return;
|
|
}
|
|
|
|
fail:
|
|
nbd_teardown_connection(bs);
|
|
}
|
|
|
|
static void nbd_restart_write(void *opaque)
|
|
{
|
|
BlockDriverState *bs = opaque;
|
|
|
|
qemu_coroutine_enter(nbd_get_client_session(bs)->send_coroutine, NULL);
|
|
}
|
|
|
|
static int nbd_co_send_request(BlockDriverState *bs,
|
|
struct nbd_request *request,
|
|
QEMUIOVector *qiov, int offset)
|
|
{
|
|
NbdClientSession *s = nbd_get_client_session(bs);
|
|
AioContext *aio_context;
|
|
int rc, ret, i;
|
|
|
|
qemu_co_mutex_lock(&s->send_mutex);
|
|
|
|
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
|
|
if (s->recv_coroutine[i] == NULL) {
|
|
s->recv_coroutine[i] = qemu_coroutine_self();
|
|
break;
|
|
}
|
|
}
|
|
|
|
g_assert(qemu_in_coroutine());
|
|
assert(i < MAX_NBD_REQUESTS);
|
|
request->handle = INDEX_TO_HANDLE(s, i);
|
|
|
|
if (!s->ioc) {
|
|
qemu_co_mutex_unlock(&s->send_mutex);
|
|
return -EPIPE;
|
|
}
|
|
|
|
s->send_coroutine = qemu_coroutine_self();
|
|
aio_context = bdrv_get_aio_context(bs);
|
|
|
|
aio_set_fd_handler(aio_context, s->sioc->fd, false,
|
|
nbd_reply_ready, nbd_restart_write, bs);
|
|
if (qiov) {
|
|
qio_channel_set_cork(s->ioc, true);
|
|
rc = nbd_send_request(s->ioc, request);
|
|
if (rc >= 0) {
|
|
ret = nbd_wr_syncv(s->ioc, qiov->iov, qiov->niov,
|
|
offset, request->len, 0);
|
|
if (ret != request->len) {
|
|
rc = -EIO;
|
|
}
|
|
}
|
|
qio_channel_set_cork(s->ioc, false);
|
|
} else {
|
|
rc = nbd_send_request(s->ioc, request);
|
|
}
|
|
aio_set_fd_handler(aio_context, s->sioc->fd, false,
|
|
nbd_reply_ready, NULL, bs);
|
|
s->send_coroutine = NULL;
|
|
qemu_co_mutex_unlock(&s->send_mutex);
|
|
return rc;
|
|
}
|
|
|
|
static void nbd_co_receive_reply(NbdClientSession *s,
|
|
struct nbd_request *request, struct nbd_reply *reply,
|
|
QEMUIOVector *qiov, int offset)
|
|
{
|
|
int ret;
|
|
|
|
/* Wait until we're woken up by the read handler. TODO: perhaps
|
|
* peek at the next reply and avoid yielding if it's ours? */
|
|
qemu_coroutine_yield();
|
|
*reply = s->reply;
|
|
if (reply->handle != request->handle ||
|
|
!s->ioc) {
|
|
reply->error = EIO;
|
|
} else {
|
|
if (qiov && reply->error == 0) {
|
|
ret = nbd_wr_syncv(s->ioc, qiov->iov, qiov->niov,
|
|
offset, request->len, 1);
|
|
if (ret != request->len) {
|
|
reply->error = EIO;
|
|
}
|
|
}
|
|
|
|
/* Tell the read handler to read another header. */
|
|
s->reply.handle = 0;
|
|
}
|
|
}
|
|
|
|
static void nbd_coroutine_start(NbdClientSession *s,
|
|
struct nbd_request *request)
|
|
{
|
|
/* Poor man semaphore. The free_sema is locked when no other request
|
|
* can be accepted, and unlocked after receiving one reply. */
|
|
if (s->in_flight >= MAX_NBD_REQUESTS - 1) {
|
|
qemu_co_mutex_lock(&s->free_sema);
|
|
assert(s->in_flight < MAX_NBD_REQUESTS);
|
|
}
|
|
s->in_flight++;
|
|
|
|
/* s->recv_coroutine[i] is set as soon as we get the send_lock. */
|
|
}
|
|
|
|
static void nbd_coroutine_end(NbdClientSession *s,
|
|
struct nbd_request *request)
|
|
{
|
|
int i = HANDLE_TO_INDEX(s, request->handle);
|
|
s->recv_coroutine[i] = NULL;
|
|
if (s->in_flight-- == MAX_NBD_REQUESTS) {
|
|
qemu_co_mutex_unlock(&s->free_sema);
|
|
}
|
|
}
|
|
|
|
static int nbd_co_readv_1(BlockDriverState *bs, int64_t sector_num,
|
|
int nb_sectors, QEMUIOVector *qiov,
|
|
int offset)
|
|
{
|
|
NbdClientSession *client = nbd_get_client_session(bs);
|
|
struct nbd_request request = { .type = NBD_CMD_READ };
|
|
struct nbd_reply reply;
|
|
ssize_t ret;
|
|
|
|
request.from = sector_num * 512;
|
|
request.len = nb_sectors * 512;
|
|
|
|
nbd_coroutine_start(client, &request);
|
|
ret = nbd_co_send_request(bs, &request, NULL, 0);
|
|
if (ret < 0) {
|
|
reply.error = -ret;
|
|
} else {
|
|
nbd_co_receive_reply(client, &request, &reply, qiov, offset);
|
|
}
|
|
nbd_coroutine_end(client, &request);
|
|
return -reply.error;
|
|
|
|
}
|
|
|
|
static int nbd_co_writev_1(BlockDriverState *bs, int64_t sector_num,
|
|
int nb_sectors, QEMUIOVector *qiov,
|
|
int offset)
|
|
{
|
|
NbdClientSession *client = nbd_get_client_session(bs);
|
|
struct nbd_request request = { .type = NBD_CMD_WRITE };
|
|
struct nbd_reply reply;
|
|
ssize_t ret;
|
|
|
|
if (!bdrv_enable_write_cache(bs) &&
|
|
(client->nbdflags & NBD_FLAG_SEND_FUA)) {
|
|
request.type |= NBD_CMD_FLAG_FUA;
|
|
}
|
|
|
|
request.from = sector_num * 512;
|
|
request.len = nb_sectors * 512;
|
|
|
|
nbd_coroutine_start(client, &request);
|
|
ret = nbd_co_send_request(bs, &request, qiov, offset);
|
|
if (ret < 0) {
|
|
reply.error = -ret;
|
|
} else {
|
|
nbd_co_receive_reply(client, &request, &reply, NULL, 0);
|
|
}
|
|
nbd_coroutine_end(client, &request);
|
|
return -reply.error;
|
|
}
|
|
|
|
/* qemu-nbd has a limit of slightly less than 1M per request. Try to
|
|
* remain aligned to 4K. */
|
|
#define NBD_MAX_SECTORS 2040
|
|
|
|
int nbd_client_co_readv(BlockDriverState *bs, int64_t sector_num,
|
|
int nb_sectors, QEMUIOVector *qiov)
|
|
{
|
|
int offset = 0;
|
|
int ret;
|
|
while (nb_sectors > NBD_MAX_SECTORS) {
|
|
ret = nbd_co_readv_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
offset += NBD_MAX_SECTORS * 512;
|
|
sector_num += NBD_MAX_SECTORS;
|
|
nb_sectors -= NBD_MAX_SECTORS;
|
|
}
|
|
return nbd_co_readv_1(bs, sector_num, nb_sectors, qiov, offset);
|
|
}
|
|
|
|
int nbd_client_co_writev(BlockDriverState *bs, int64_t sector_num,
|
|
int nb_sectors, QEMUIOVector *qiov)
|
|
{
|
|
int offset = 0;
|
|
int ret;
|
|
while (nb_sectors > NBD_MAX_SECTORS) {
|
|
ret = nbd_co_writev_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
offset += NBD_MAX_SECTORS * 512;
|
|
sector_num += NBD_MAX_SECTORS;
|
|
nb_sectors -= NBD_MAX_SECTORS;
|
|
}
|
|
return nbd_co_writev_1(bs, sector_num, nb_sectors, qiov, offset);
|
|
}
|
|
|
|
int nbd_client_co_flush(BlockDriverState *bs)
|
|
{
|
|
NbdClientSession *client = nbd_get_client_session(bs);
|
|
struct nbd_request request = { .type = NBD_CMD_FLUSH };
|
|
struct nbd_reply reply;
|
|
ssize_t ret;
|
|
|
|
if (!(client->nbdflags & NBD_FLAG_SEND_FLUSH)) {
|
|
return 0;
|
|
}
|
|
|
|
if (client->nbdflags & NBD_FLAG_SEND_FUA) {
|
|
request.type |= NBD_CMD_FLAG_FUA;
|
|
}
|
|
|
|
request.from = 0;
|
|
request.len = 0;
|
|
|
|
nbd_coroutine_start(client, &request);
|
|
ret = nbd_co_send_request(bs, &request, NULL, 0);
|
|
if (ret < 0) {
|
|
reply.error = -ret;
|
|
} else {
|
|
nbd_co_receive_reply(client, &request, &reply, NULL, 0);
|
|
}
|
|
nbd_coroutine_end(client, &request);
|
|
return -reply.error;
|
|
}
|
|
|
|
int nbd_client_co_discard(BlockDriverState *bs, int64_t sector_num,
|
|
int nb_sectors)
|
|
{
|
|
NbdClientSession *client = nbd_get_client_session(bs);
|
|
struct nbd_request request = { .type = NBD_CMD_TRIM };
|
|
struct nbd_reply reply;
|
|
ssize_t ret;
|
|
|
|
if (!(client->nbdflags & NBD_FLAG_SEND_TRIM)) {
|
|
return 0;
|
|
}
|
|
request.from = sector_num * 512;
|
|
request.len = nb_sectors * 512;
|
|
|
|
nbd_coroutine_start(client, &request);
|
|
ret = nbd_co_send_request(bs, &request, NULL, 0);
|
|
if (ret < 0) {
|
|
reply.error = -ret;
|
|
} else {
|
|
nbd_co_receive_reply(client, &request, &reply, NULL, 0);
|
|
}
|
|
nbd_coroutine_end(client, &request);
|
|
return -reply.error;
|
|
|
|
}
|
|
|
|
void nbd_client_detach_aio_context(BlockDriverState *bs)
|
|
{
|
|
aio_set_fd_handler(bdrv_get_aio_context(bs),
|
|
nbd_get_client_session(bs)->sioc->fd,
|
|
false, NULL, NULL, NULL);
|
|
}
|
|
|
|
void nbd_client_attach_aio_context(BlockDriverState *bs,
|
|
AioContext *new_context)
|
|
{
|
|
aio_set_fd_handler(new_context, nbd_get_client_session(bs)->sioc->fd,
|
|
false, nbd_reply_ready, NULL, bs);
|
|
}
|
|
|
|
void nbd_client_close(BlockDriverState *bs)
|
|
{
|
|
NbdClientSession *client = nbd_get_client_session(bs);
|
|
struct nbd_request request = {
|
|
.type = NBD_CMD_DISC,
|
|
.from = 0,
|
|
.len = 0
|
|
};
|
|
|
|
if (client->ioc == NULL) {
|
|
return;
|
|
}
|
|
|
|
nbd_send_request(client->ioc, &request);
|
|
|
|
nbd_teardown_connection(bs);
|
|
}
|
|
|
|
int nbd_client_init(BlockDriverState *bs, QIOChannelSocket *sioc,
|
|
const char *export, Error **errp)
|
|
{
|
|
NbdClientSession *client = nbd_get_client_session(bs);
|
|
int ret;
|
|
|
|
/* NBD handshake */
|
|
logout("session init %s\n", export);
|
|
qio_channel_set_blocking(QIO_CHANNEL(sioc), true, NULL);
|
|
|
|
ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), export,
|
|
&client->nbdflags, &client->size, errp);
|
|
if (ret < 0) {
|
|
logout("Failed to negotiate with the NBD server\n");
|
|
return ret;
|
|
}
|
|
|
|
qemu_co_mutex_init(&client->send_mutex);
|
|
qemu_co_mutex_init(&client->free_sema);
|
|
client->sioc = sioc;
|
|
object_ref(OBJECT(client->sioc));
|
|
client->ioc = QIO_CHANNEL(sioc);
|
|
object_ref(OBJECT(client->ioc));
|
|
|
|
/* Now that we're connected, set the socket to be non-blocking and
|
|
* kick the reply mechanism. */
|
|
qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
|
|
|
|
nbd_client_attach_aio_context(bs, bdrv_get_aio_context(bs));
|
|
|
|
logout("Established connection with NBD server\n");
|
|
return 0;
|
|
}
|