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qemu/nbd.c
Paolo Bonzini 262db38871 qemu-nbd: asynchronous operation 
Using coroutines enable asynchronous operation on both the network and
the block side.  Network can be owned by two coroutines at the same time,
one writing and one reading.  On the send side, mutual exclusion is
guaranteed by a CoMutex.  On the receive side, mutual exclusion is
guaranteed because new coroutines immediately start receiving data,
and no new coroutines are created as long as the previous one is receiving.

Between receive and send, qemu-nbd can have an arbitrary number of
in-flight block transfers.  Throttling is implemented by the next
patch.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2011-12-22 11:53:59 +01:00

936 lines
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/*
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; under version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "nbd.h"
#include "block.h"
#include "block_int.h"
#include "qemu-coroutine.h"
#include <errno.h>
#include <string.h>
#ifndef _WIN32
#include <sys/ioctl.h>
#endif
#if defined(__sun__) || defined(__HAIKU__)
#include <sys/ioccom.h>
#endif
#include <ctype.h>
#include <inttypes.h>
#ifdef __linux__
#include <linux/fs.h>
#endif
#include "qemu_socket.h"
#include "qemu-queue.h"
//#define DEBUG_NBD
#ifdef DEBUG_NBD
#define TRACE(msg, ...) do { \
LOG(msg, ## __VA_ARGS__); \
} while(0)
#else
#define TRACE(msg, ...) \
do { } while (0)
#endif
#define LOG(msg, ...) do { \
fprintf(stderr, "%s:%s():L%d: " msg "\n", \
__FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
} while(0)
/* This is all part of the "official" NBD API */
#define NBD_REPLY_SIZE (4 + 4 + 8)
#define NBD_REQUEST_MAGIC 0x25609513
#define NBD_REPLY_MAGIC 0x67446698
#define NBD_SET_SOCK _IO(0xab, 0)
#define NBD_SET_BLKSIZE _IO(0xab, 1)
#define NBD_SET_SIZE _IO(0xab, 2)
#define NBD_DO_IT _IO(0xab, 3)
#define NBD_CLEAR_SOCK _IO(0xab, 4)
#define NBD_CLEAR_QUE _IO(0xab, 5)
#define NBD_PRINT_DEBUG _IO(0xab, 6)
#define NBD_SET_SIZE_BLOCKS _IO(0xab, 7)
#define NBD_DISCONNECT _IO(0xab, 8)
#define NBD_SET_TIMEOUT _IO(0xab, 9)
#define NBD_SET_FLAGS _IO(0xab, 10)
#define NBD_OPT_EXPORT_NAME (1 << 0)
/* That's all folks */
#define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
#define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false)
size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
{
size_t offset = 0;
if (qemu_in_coroutine()) {
if (do_read) {
return qemu_co_recv(fd, buffer, size);
} else {
return qemu_co_send(fd, buffer, size);
}
}
while (offset < size) {
ssize_t len;
if (do_read) {
len = qemu_recv(fd, buffer + offset, size - offset, 0);
} else {
len = send(fd, buffer + offset, size - offset, 0);
}
if (len == -1)
errno = socket_error();
/* recoverable error */
if (len == -1 && (errno == EAGAIN || errno == EINTR)) {
continue;
}
/* eof */
if (len == 0) {
break;
}
/* unrecoverable error */
if (len == -1) {
return 0;
}
offset += len;
}
return offset;
}
static void combine_addr(char *buf, size_t len, const char* address,
uint16_t port)
{
/* If the address-part contains a colon, it's an IPv6 IP so needs [] */
if (strstr(address, ":")) {
snprintf(buf, len, "[%s]:%u", address, port);
} else {
snprintf(buf, len, "%s:%u", address, port);
}
}
int tcp_socket_outgoing(const char *address, uint16_t port)
{
char address_and_port[128];
combine_addr(address_and_port, 128, address, port);
return tcp_socket_outgoing_spec(address_and_port);
}
int tcp_socket_outgoing_spec(const char *address_and_port)
{
return inet_connect(address_and_port, SOCK_STREAM);
}
int tcp_socket_incoming(const char *address, uint16_t port)
{
char address_and_port[128];
combine_addr(address_and_port, 128, address, port);
return tcp_socket_incoming_spec(address_and_port);
}
int tcp_socket_incoming_spec(const char *address_and_port)
{
char *ostr = NULL;
int olen = 0;
return inet_listen(address_and_port, ostr, olen, SOCK_STREAM, 0);
}
int unix_socket_incoming(const char *path)
{
char *ostr = NULL;
int olen = 0;
return unix_listen(path, ostr, olen);
}
int unix_socket_outgoing(const char *path)
{
return unix_connect(path);
}
/* Basic flow
Server Client
Negotiate
Request
Response
Request
Response
...
...
Request (type == 2)
*/
static int nbd_send_negotiate(int csock, off_t size, uint32_t flags)
{
char buf[8 + 8 + 8 + 128];
/* Negotiate
[ 0 .. 7] passwd ("NBDMAGIC")
[ 8 .. 15] magic (0x00420281861253)
[16 .. 23] size
[24 .. 27] flags
[28 .. 151] reserved (0)
*/
TRACE("Beginning negotiation.");
memcpy(buf, "NBDMAGIC", 8);
cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
cpu_to_be64w((uint64_t*)(buf + 16), size);
cpu_to_be32w((uint32_t*)(buf + 24),
flags | NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);
memset(buf + 28, 0, 124);
if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("write failed");
errno = EINVAL;
return -1;
}
TRACE("Negotiation succeeded.");
return 0;
}
int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
off_t *size, size_t *blocksize)
{
char buf[256];
uint64_t magic, s;
uint16_t tmp;
TRACE("Receiving negotiation.");
if (read_sync(csock, buf, 8) != 8) {
LOG("read failed");
errno = EINVAL;
return -1;
}
buf[8] = '\0';
if (strlen(buf) == 0) {
LOG("server connection closed");
errno = EINVAL;
return -1;
}
TRACE("Magic is %c%c%c%c%c%c%c%c",
qemu_isprint(buf[0]) ? buf[0] : '.',
qemu_isprint(buf[1]) ? buf[1] : '.',
qemu_isprint(buf[2]) ? buf[2] : '.',
qemu_isprint(buf[3]) ? buf[3] : '.',
qemu_isprint(buf[4]) ? buf[4] : '.',
qemu_isprint(buf[5]) ? buf[5] : '.',
qemu_isprint(buf[6]) ? buf[6] : '.',
qemu_isprint(buf[7]) ? buf[7] : '.');
if (memcmp(buf, "NBDMAGIC", 8) != 0) {
LOG("Invalid magic received");
errno = EINVAL;
return -1;
}
if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("read failed");
errno = EINVAL;
return -1;
}
magic = be64_to_cpu(magic);
TRACE("Magic is 0x%" PRIx64, magic);
if (name) {
uint32_t reserved = 0;
uint32_t opt;
uint32_t namesize;
TRACE("Checking magic (opts_magic)");
if (magic != 0x49484156454F5054LL) {
LOG("Bad magic received");
errno = EINVAL;
return -1;
}
if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
LOG("flags read failed");
errno = EINVAL;
return -1;
}
*flags = be16_to_cpu(tmp) << 16;
/* reserved for future use */
if (write_sync(csock, &reserved, sizeof(reserved)) !=
sizeof(reserved)) {
LOG("write failed (reserved)");
errno = EINVAL;
return -1;
}
/* write the export name */
magic = cpu_to_be64(magic);
if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("write failed (magic)");
errno = EINVAL;
return -1;
}
opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
LOG("write failed (opt)");
errno = EINVAL;
return -1;
}
namesize = cpu_to_be32(strlen(name));
if (write_sync(csock, &namesize, sizeof(namesize)) !=
sizeof(namesize)) {
LOG("write failed (namesize)");
errno = EINVAL;
return -1;
}
if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) {
LOG("write failed (name)");
errno = EINVAL;
return -1;
}
} else {
TRACE("Checking magic (cli_magic)");
if (magic != 0x00420281861253LL) {
LOG("Bad magic received");
errno = EINVAL;
return -1;
}
}
if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) {
LOG("read failed");
errno = EINVAL;
return -1;
}
*size = be64_to_cpu(s);
*blocksize = 1024;
TRACE("Size is %" PRIu64, *size);
if (!name) {
if (read_sync(csock, flags, sizeof(*flags)) != sizeof(*flags)) {
LOG("read failed (flags)");
errno = EINVAL;
return -1;
}
*flags = be32_to_cpup(flags);
} else {
if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
LOG("read failed (tmp)");
errno = EINVAL;
return -1;
}
*flags |= be32_to_cpu(tmp);
}
if (read_sync(csock, &buf, 124) != 124) {
LOG("read failed (buf)");
errno = EINVAL;
return -1;
}
return 0;
}
#ifdef __linux__
int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
{
TRACE("Setting NBD socket");
if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
int serrno = errno;
LOG("Failed to set NBD socket");
errno = serrno;
return -1;
}
TRACE("Setting block size to %lu", (unsigned long)blocksize);
if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
int serrno = errno;
LOG("Failed setting NBD block size");
errno = serrno;
return -1;
}
TRACE("Setting size to %zd block(s)", (size_t)(size / blocksize));
if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) == -1) {
int serrno = errno;
LOG("Failed setting size (in blocks)");
errno = serrno;
return -1;
}
if (flags & NBD_FLAG_READ_ONLY) {
int read_only = 1;
TRACE("Setting readonly attribute");
if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
int serrno = errno;
LOG("Failed setting read-only attribute");
errno = serrno;
return -1;
}
}
if (ioctl(fd, NBD_SET_FLAGS, flags) < 0
&& errno != ENOTTY) {
int serrno = errno;
LOG("Failed setting flags");
errno = serrno;
return -1;
}
TRACE("Negotiation ended");
return 0;
}
int nbd_disconnect(int fd)
{
ioctl(fd, NBD_CLEAR_QUE);
ioctl(fd, NBD_DISCONNECT);
ioctl(fd, NBD_CLEAR_SOCK);
return 0;
}
int nbd_client(int fd)
{
int ret;
int serrno;
TRACE("Doing NBD loop");
ret = ioctl(fd, NBD_DO_IT);
if (ret == -1 && errno == EPIPE) {
/* NBD_DO_IT normally returns EPIPE when someone has disconnected
* the socket via NBD_DISCONNECT. We do not want to return 1 in
* that case.
*/
ret = 0;
}
serrno = errno;
TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
TRACE("Clearing NBD queue");
ioctl(fd, NBD_CLEAR_QUE);
TRACE("Clearing NBD socket");
ioctl(fd, NBD_CLEAR_SOCK);
errno = serrno;
return ret;
}
#else
int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
{
errno = ENOTSUP;
return -1;
}
int nbd_disconnect(int fd)
{
errno = ENOTSUP;
return -1;
}
int nbd_client(int fd)
{
errno = ENOTSUP;
return -1;
}
#endif
int nbd_send_request(int csock, struct nbd_request *request)
{
uint8_t buf[4 + 4 + 8 + 8 + 4];
cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
cpu_to_be32w((uint32_t*)(buf + 4), request->type);
cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
cpu_to_be64w((uint64_t*)(buf + 16), request->from);
cpu_to_be32w((uint32_t*)(buf + 24), request->len);
TRACE("Sending request to client: "
"{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}",
request->from, request->len, request->handle, request->type);
if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("writing to socket failed");
errno = EINVAL;
return -1;
}
return 0;
}
static int nbd_receive_request(int csock, struct nbd_request *request)
{
uint8_t buf[4 + 4 + 8 + 8 + 4];
uint32_t magic;
if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("read failed");
errno = EINVAL;
return -1;
}
/* Request
[ 0 .. 3] magic (NBD_REQUEST_MAGIC)
[ 4 .. 7] type (0 == READ, 1 == WRITE)
[ 8 .. 15] handle
[16 .. 23] from
[24 .. 27] len
*/
magic = be32_to_cpup((uint32_t*)buf);
request->type = be32_to_cpup((uint32_t*)(buf + 4));
request->handle = be64_to_cpup((uint64_t*)(buf + 8));
request->from = be64_to_cpup((uint64_t*)(buf + 16));
request->len = be32_to_cpup((uint32_t*)(buf + 24));
TRACE("Got request: "
"{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
magic, request->type, request->from, request->len);
if (magic != NBD_REQUEST_MAGIC) {
LOG("invalid magic (got 0x%x)", magic);
errno = EINVAL;
return -1;
}
return 0;
}
int nbd_receive_reply(int csock, struct nbd_reply *reply)
{
uint8_t buf[NBD_REPLY_SIZE];
uint32_t magic;
memset(buf, 0xAA, sizeof(buf));
if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("read failed");
errno = EINVAL;
return -1;
}
/* Reply
[ 0 .. 3] magic (NBD_REPLY_MAGIC)
[ 4 .. 7] error (0 == no error)
[ 7 .. 15] handle
*/
magic = be32_to_cpup((uint32_t*)buf);
reply->error = be32_to_cpup((uint32_t*)(buf + 4));
reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
TRACE("Got reply: "
"{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
magic, reply->error, reply->handle);
if (magic != NBD_REPLY_MAGIC) {
LOG("invalid magic (got 0x%x)", magic);
errno = EINVAL;
return -1;
}
return 0;
}
static int nbd_send_reply(int csock, struct nbd_reply *reply)
{
uint8_t buf[4 + 4 + 8];
/* Reply
[ 0 .. 3] magic (NBD_REPLY_MAGIC)
[ 4 .. 7] error (0 == no error)
[ 7 .. 15] handle
*/
cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
cpu_to_be32w((uint32_t*)(buf + 4), reply->error);
cpu_to_be64w((uint64_t*)(buf + 8), reply->handle);
TRACE("Sending response to client");
if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("writing to socket failed");
errno = EINVAL;
return -1;
}
return 0;
}
typedef struct NBDRequest NBDRequest;
struct NBDRequest {
QSIMPLEQ_ENTRY(NBDRequest) entry;
NBDClient *client;
uint8_t *data;
};
struct NBDExport {
BlockDriverState *bs;
off_t dev_offset;
off_t size;
uint32_t nbdflags;
QSIMPLEQ_HEAD(, NBDRequest) requests;
};
struct NBDClient {
int refcount;
void (*close)(NBDClient *client);
NBDExport *exp;
int sock;
Coroutine *recv_coroutine;
CoMutex send_lock;
Coroutine *send_coroutine;
};
static void nbd_client_get(NBDClient *client)
{
client->refcount++;
}
static void nbd_client_put(NBDClient *client)
{
if (--client->refcount == 0) {
g_free(client);
}
}
static void nbd_client_close(NBDClient *client)
{
qemu_set_fd_handler2(client->sock, NULL, NULL, NULL, NULL);
close(client->sock);
client->sock = -1;
if (client->close) {
client->close(client);
}
nbd_client_put(client);
}
static NBDRequest *nbd_request_get(NBDClient *client)
{
NBDRequest *req;
NBDExport *exp = client->exp;
if (QSIMPLEQ_EMPTY(&exp->requests)) {
req = g_malloc0(sizeof(NBDRequest));
req->data = qemu_blockalign(exp->bs, NBD_BUFFER_SIZE);
} else {
req = QSIMPLEQ_FIRST(&exp->requests);
QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry);
}
nbd_client_get(client);
req->client = client;
return req;
}
static void nbd_request_put(NBDRequest *req)
{
NBDClient *client = req->client;
QSIMPLEQ_INSERT_HEAD(&client->exp->requests, req, entry);
nbd_client_put(client);
}
NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset,
off_t size, uint32_t nbdflags)
{
NBDExport *exp = g_malloc0(sizeof(NBDExport));
QSIMPLEQ_INIT(&exp->requests);
exp->bs = bs;
exp->dev_offset = dev_offset;
exp->nbdflags = nbdflags;
exp->size = size == -1 ? exp->bs->total_sectors * 512 : size;
return exp;
}
void nbd_export_close(NBDExport *exp)
{
while (!QSIMPLEQ_EMPTY(&exp->requests)) {
NBDRequest *first = QSIMPLEQ_FIRST(&exp->requests);
QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry);
qemu_vfree(first->data);
g_free(first);
}
bdrv_close(exp->bs);
g_free(exp);
}
static void nbd_read(void *opaque);
static void nbd_restart_write(void *opaque);
static int nbd_co_send_reply(NBDRequest *req, struct nbd_reply *reply,
int len)
{
NBDClient *client = req->client;
int csock = client->sock;
int rc, ret;
qemu_co_mutex_lock(&client->send_lock);
qemu_set_fd_handler2(csock, NULL, nbd_read, nbd_restart_write, client);
client->send_coroutine = qemu_coroutine_self();
if (!len) {
rc = nbd_send_reply(csock, reply);
if (rc == -1) {
rc = -errno;
}
} else {
socket_set_cork(csock, 1);
rc = nbd_send_reply(csock, reply);
if (rc != -1) {
ret = qemu_co_send(csock, req->data, len);
if (ret != len) {
errno = EIO;
rc = -1;
}
}
if (rc == -1) {
rc = -errno;
}
socket_set_cork(csock, 0);
}
client->send_coroutine = NULL;
qemu_set_fd_handler2(csock, NULL, nbd_read, NULL, client);
qemu_co_mutex_unlock(&client->send_lock);
return rc;
}
static int nbd_co_receive_request(NBDRequest *req, struct nbd_request *request)
{
NBDClient *client = req->client;
int csock = client->sock;
int rc;
client->recv_coroutine = qemu_coroutine_self();
if (nbd_receive_request(csock, request) == -1) {
rc = -EIO;
goto out;
}
if (request->len > NBD_BUFFER_SIZE) {
LOG("len (%u) is larger than max len (%u)",
request->len, NBD_BUFFER_SIZE);
rc = -EINVAL;
goto out;
}
if ((request->from + request->len) < request->from) {
LOG("integer overflow detected! "
"you're probably being attacked");
rc = -EINVAL;
goto out;
}
TRACE("Decoding type");
if ((request->type & NBD_CMD_MASK_COMMAND) == NBD_CMD_WRITE) {
TRACE("Reading %u byte(s)", request->len);
if (qemu_co_recv(csock, req->data, request->len) != request->len) {
LOG("reading from socket failed");
rc = -EIO;
goto out;
}
}
rc = 0;
out:
client->recv_coroutine = NULL;
return rc;
}
static void nbd_trip(void *opaque)
{
NBDClient *client = opaque;
NBDRequest *req = nbd_request_get(client);
NBDExport *exp = client->exp;
struct nbd_request request;
struct nbd_reply reply;
int ret;
TRACE("Reading request.");
ret = nbd_co_receive_request(req, &request);
if (ret == -EIO) {
goto out;
}
reply.handle = request.handle;
reply.error = 0;
if (ret < 0) {
reply.error = -ret;
goto error_reply;
}
if ((request.from + request.len) > exp->size) {
LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
", Offset: %" PRIu64 "\n",
request.from, request.len,
(uint64_t)exp->size, exp->dev_offset);
LOG("requested operation past EOF--bad client?");
goto invalid_request;
}
switch (request.type & NBD_CMD_MASK_COMMAND) {
case NBD_CMD_READ:
TRACE("Request type is READ");
ret = bdrv_read(exp->bs, (request.from + exp->dev_offset) / 512,
req->data, request.len / 512);
if (ret < 0) {
LOG("reading from file failed");
reply.error = -ret;
goto error_reply;
}
TRACE("Read %u byte(s)", request.len);
if (nbd_co_send_reply(req, &reply, request.len) < 0)
goto out;
break;
case NBD_CMD_WRITE:
TRACE("Request type is WRITE");
if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
TRACE("Server is read-only, return error");
reply.error = EROFS;
goto error_reply;
}
TRACE("Writing to device");
ret = bdrv_write(exp->bs, (request.from + exp->dev_offset) / 512,
req->data, request.len / 512);
if (ret < 0) {
LOG("writing to file failed");
reply.error = -ret;
goto error_reply;
}
if (request.type & NBD_CMD_FLAG_FUA) {
ret = bdrv_co_flush(exp->bs);
if (ret < 0) {
LOG("flush failed");
reply.error = -ret;
goto error_reply;
}
}
if (nbd_co_send_reply(req, &reply, 0) < 0)
goto out;
break;
case NBD_CMD_DISC:
TRACE("Request type is DISCONNECT");
errno = 0;
goto out;
case NBD_CMD_FLUSH:
TRACE("Request type is FLUSH");
ret = bdrv_co_flush(exp->bs);
if (ret < 0) {
LOG("flush failed");
reply.error = -ret;
}
if (nbd_co_send_reply(req, &reply, 0) < 0)
goto out;
break;
case NBD_CMD_TRIM:
TRACE("Request type is TRIM");
ret = bdrv_co_discard(exp->bs, (request.from + exp->dev_offset) / 512,
request.len / 512);
if (ret < 0) {
LOG("discard failed");
reply.error = -ret;
}
if (nbd_co_send_reply(req, &reply, 0) < 0)
goto out;
break;
default:
LOG("invalid request type (%u) received", request.type);
invalid_request:
reply.error = -EINVAL;
error_reply:
if (nbd_co_send_reply(req, &reply, 0) == -1)
goto out;
break;
}
TRACE("Request/Reply complete");
nbd_request_put(req);
return;
out:
nbd_request_put(req);
nbd_client_close(client);
}
static void nbd_read(void *opaque)
{
NBDClient *client = opaque;
if (client->recv_coroutine) {
qemu_coroutine_enter(client->recv_coroutine, NULL);
} else {
qemu_coroutine_enter(qemu_coroutine_create(nbd_trip), client);
}
}
static void nbd_restart_write(void *opaque)
{
NBDClient *client = opaque;
qemu_coroutine_enter(client->send_coroutine, NULL);
}
NBDClient *nbd_client_new(NBDExport *exp, int csock,
void (*close)(NBDClient *))
{
NBDClient *client;
if (nbd_send_negotiate(csock, exp->size, exp->nbdflags) == -1) {
return NULL;
}
client = g_malloc0(sizeof(NBDClient));
client->refcount = 1;
client->exp = exp;
client->sock = csock;
client->close = close;
qemu_co_mutex_init(&client->send_lock);
qemu_set_fd_handler2(csock, NULL, nbd_read, NULL, client);
return client;
}
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