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qemu-e2k/block/nbd.c
Stefan Hajnoczi e8b6535533 block: add BDRV_REQ_REGISTERED_BUF request flag 
Block drivers may optimize I/O requests accessing buffers previously
registered with bdrv_register_buf(). Checking whether all elements of a
request's QEMUIOVector are within previously registered buffers is
expensive, so we need a hint from the user to avoid costly checks.

Add a BDRV_REQ_REGISTERED_BUF request flag to indicate that all
QEMUIOVector elements in an I/O request are known to be within
previously registered buffers.

Always pass the flag through to driver read/write functions. There is
little harm in passing the flag to a driver that does not use it.
Passing the flag to drivers avoids changes across many block drivers.
Filter drivers would need to explicitly support the flag and pass
through to their children when the children support it. That's a lot of
code changes and it's hard to remember to do that everywhere, leading to
silent reduced performance when the flag is accidentally dropped.

The only problematic scenario with the approach in this patch is when a
driver passes the flag through to internal I/O requests that don't use
the same I/O buffer. In that case the hint may be set when it should
actually be clear. This is a rare case though so the risk is low.

Some drivers have assert(!flags), which no longer works when
BDRV_REQ_REGISTERED_BUF is passed in. These assertions aren't very
useful anyway since the functions are called almost exclusively by
bdrv_driver_preadv/pwritev() so if we get flags handling right there
then the assertion is not needed.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20221013185908.1297568-7-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-10-26 14:56:42 -04:00

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/*
* QEMU Block driver for NBD
*
* Copyright (c) 2019 Virtuozzo International GmbH.
* Copyright (C) 2016 Red Hat, Inc.
* Copyright (C) 2008 Bull S.A.S.
* Author: Laurent Vivier <Laurent.Vivier@bull.net>
*
* Some parts:
* Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "trace.h"
#include "qemu/uri.h"
#include "qemu/option.h"
#include "qemu/cutils.h"
#include "qemu/main-loop.h"
#include "qapi/qapi-visit-sockets.h"
#include "qapi/qmp/qstring.h"
#include "qapi/clone-visitor.h"
#include "block/qdict.h"
#include "block/nbd.h"
#include "block/block_int.h"
#include "block/coroutines.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; /* sleeping in the yield in nbd_receive_replies */
} NBDClientRequest;
typedef enum NBDClientState {
NBD_CLIENT_CONNECTING_WAIT,
NBD_CLIENT_CONNECTING_NOWAIT,
NBD_CLIENT_CONNECTED,
NBD_CLIENT_QUIT
} NBDClientState;
typedef struct BDRVNBDState {
QIOChannel *ioc; /* The current I/O channel */
NBDExportInfo info;
/*
* Protects state, free_sema, in_flight, requests[].coroutine,
* reconnect_delay_timer.
*/
QemuMutex requests_lock;
NBDClientState state;
CoQueue free_sema;
unsigned in_flight;
NBDClientRequest requests[MAX_NBD_REQUESTS];
QEMUTimer *reconnect_delay_timer;
/* Protects sending data on the socket. */
CoMutex send_mutex;
/*
* Protects receiving reply headers from the socket, as well as the
* fields reply and requests[].receiving
*/
CoMutex receive_mutex;
NBDReply reply;
QEMUTimer *open_timer;
BlockDriverState *bs;
/* Connection parameters */
uint32_t reconnect_delay;
uint32_t open_timeout;
SocketAddress *saddr;
char *export;
char *tlscredsid;
QCryptoTLSCreds *tlscreds;
char *tlshostname;
char *x_dirty_bitmap;
bool alloc_depth;
NBDClientConnection *conn;
} BDRVNBDState;
static void nbd_yank(void *opaque);
static void nbd_clear_bdrvstate(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
nbd_client_connection_release(s->conn);
s->conn = NULL;
yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name));
/* Must not leave timers behind that would access freed data */
assert(!s->reconnect_delay_timer);
assert(!s->open_timer);
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->tlshostname);
s->tlshostname = NULL;
g_free(s->x_dirty_bitmap);
s->x_dirty_bitmap = NULL;
}
/* Called with s->receive_mutex taken. */
static bool coroutine_fn nbd_recv_coroutine_wake_one(NBDClientRequest *req)
{
if (req->receiving) {
req->receiving = false;
aio_co_wake(req->coroutine);
return true;
}
return false;
}
static void coroutine_fn nbd_recv_coroutines_wake(BDRVNBDState *s)
{
int i;
QEMU_LOCK_GUARD(&s->receive_mutex);
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
if (nbd_recv_coroutine_wake_one(&s->requests[i])) {
return;
}
}
}
/* Called with s->requests_lock held. */
static void coroutine_fn nbd_channel_error_locked(BDRVNBDState *s, int ret)
{
if (s->state == NBD_CLIENT_CONNECTED) {
qio_channel_shutdown(s->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
}
if (ret == -EIO) {
if (s->state == NBD_CLIENT_CONNECTED) {
s->state = s->reconnect_delay ? NBD_CLIENT_CONNECTING_WAIT :
NBD_CLIENT_CONNECTING_NOWAIT;
}
} else {
s->state = NBD_CLIENT_QUIT;
}
}
static void coroutine_fn nbd_channel_error(BDRVNBDState *s, int ret)
{
QEMU_LOCK_GUARD(&s->requests_lock);
nbd_channel_error_locked(s, ret);
}
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;
reconnect_delay_timer_del(s);
WITH_QEMU_LOCK_GUARD(&s->requests_lock) {
if (s->state != NBD_CLIENT_CONNECTING_WAIT) {
return;
}
s->state = NBD_CLIENT_CONNECTING_NOWAIT;
}
nbd_co_establish_connection_cancel(s->conn);
}
static void reconnect_delay_timer_init(BDRVNBDState *s, uint64_t expire_time_ns)
{
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_teardown_connection(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
assert(!s->in_flight);
if (s->ioc) {
qio_channel_shutdown(s->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
yank_unregister_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name),
nbd_yank, s->bs);
object_unref(OBJECT(s->ioc));
s->ioc = NULL;
}
WITH_QEMU_LOCK_GUARD(&s->requests_lock) {
s->state = NBD_CLIENT_QUIT;
}
}
static void open_timer_del(BDRVNBDState *s)
{
if (s->open_timer) {
timer_free(s->open_timer);
s->open_timer = NULL;
}
}
static void open_timer_cb(void *opaque)
{
BDRVNBDState *s = opaque;
nbd_co_establish_connection_cancel(s->conn);
open_timer_del(s);
}
static void open_timer_init(BDRVNBDState *s, uint64_t expire_time_ns)
{
assert(!s->open_timer);
s->open_timer = aio_timer_new(bdrv_get_aio_context(s->bs),
QEMU_CLOCK_REALTIME,
SCALE_NS,
open_timer_cb, s);
timer_mod(s->open_timer, expire_time_ns);
}
static bool nbd_client_will_reconnect(BDRVNBDState *s)
{
/*
* Called only after a socket error, so this is not performance sensitive.
*/
QEMU_LOCK_GUARD(&s->requests_lock);
return s->state == NBD_CLIENT_CONNECTING_WAIT;
}
/*
* Update @bs with information learned during a completed negotiation process.
* Return failure if the server's advertised options are incompatible with the
* client's needs.
*/
static int nbd_handle_updated_info(BlockDriverState *bs, Error **errp)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
int 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);
return -EINVAL;
}
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) {
return ret;
}
}
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;
}
}
trace_nbd_client_handshake_success(s->export);
return 0;
}
int coroutine_fn nbd_co_do_establish_connection(BlockDriverState *bs,
bool blocking, Error **errp)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
int ret;
IO_CODE();
assert(!s->ioc);
s->ioc = nbd_co_establish_connection(s->conn, &s->info, blocking, errp);
if (!s->ioc) {
return -ECONNREFUSED;
}
yank_register_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank,
bs);
ret = nbd_handle_updated_info(s->bs, NULL);
if (ret < 0) {
/*
* 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, &request);
yank_unregister_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name),
nbd_yank, bs);
object_unref(OBJECT(s->ioc));
s->ioc = NULL;
return ret;
}
qio_channel_set_blocking(s->ioc, false, NULL);
qio_channel_attach_aio_context(s->ioc, bdrv_get_aio_context(bs));
/* successfully connected */
WITH_QEMU_LOCK_GUARD(&s->requests_lock) {
s->state = NBD_CLIENT_CONNECTED;
}
return 0;
}
/* Called with s->requests_lock held. */
static bool nbd_client_connecting(BDRVNBDState *s)
{
return s->state == NBD_CLIENT_CONNECTING_WAIT ||
s->state == NBD_CLIENT_CONNECTING_NOWAIT;
}
/* Called with s->requests_lock taken. */
static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s)
{
int ret;
bool blocking = s->state == NBD_CLIENT_CONNECTING_WAIT;
/*
* Now we are sure that nobody is accessing the channel, and no one will
* try until we set the state to CONNECTED.
*/
assert(nbd_client_connecting(s));
assert(s->in_flight == 1);
trace_nbd_reconnect_attempt(s->bs->in_flight);
if (blocking && !s->reconnect_delay_timer) {
/*
* It's the first reconnect attempt after switching to
* NBD_CLIENT_CONNECTING_WAIT
*/
g_assert(s->reconnect_delay);
reconnect_delay_timer_init(s,
qemu_clock_get_ns(QEMU_CLOCK_REALTIME) +
s->reconnect_delay * NANOSECONDS_PER_SECOND);
}
/* 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->ioc));
s->ioc = NULL;
}
qemu_mutex_unlock(&s->requests_lock);
ret = nbd_co_do_establish_connection(s->bs, blocking, NULL);
trace_nbd_reconnect_attempt_result(ret, s->bs->in_flight);
qemu_mutex_lock(&s->requests_lock);
/*
* The reconnect attempt is done (maybe successfully, maybe not), so
* we no longer need this timer. Delete it so it will not outlive
* this I/O request (so draining removes all timers).
*/
reconnect_delay_timer_del(s);
}
static coroutine_fn int nbd_receive_replies(BDRVNBDState *s, uint64_t handle)
{
int ret;
uint64_t ind = HANDLE_TO_INDEX(s, handle), ind2;
QEMU_LOCK_GUARD(&s->receive_mutex);
while (true) {
if (s->reply.handle == handle) {
/* We are done */
return 0;
}
if (s->reply.handle != 0) {
/*
* Some other request is being handled now. It should already be
* woken by whoever set s->reply.handle (or never wait in this
* yield). So, we should not wake it here.
*/
ind2 = HANDLE_TO_INDEX(s, s->reply.handle);
assert(!s->requests[ind2].receiving);
s->requests[ind].receiving = true;
qemu_co_mutex_unlock(&s->receive_mutex);
qemu_coroutine_yield();
/*
* We may be woken for 2 reasons:
* 1. From this function, executing in parallel coroutine, when our
* handle is received.
* 2. From nbd_co_receive_one_chunk(), when previous request is
* finished and s->reply.handle set to 0.
* Anyway, it's OK to lock the mutex and go to the next iteration.
*/
qemu_co_mutex_lock(&s->receive_mutex);
assert(!s->requests[ind].receiving);
continue;
}
/* We are under mutex and handle is 0. We have to do the dirty work. */
assert(s->reply.handle == 0);
ret = nbd_receive_reply(s->bs, s->ioc, &s->reply, NULL);
if (ret <= 0) {
ret = ret ? ret : -EIO;
nbd_channel_error(s, ret);
return ret;
}
if (nbd_reply_is_structured(&s->reply) && !s->info.structured_reply) {
nbd_channel_error(s, -EINVAL);
return -EINVAL;
}
ind2 = HANDLE_TO_INDEX(s, s->reply.handle);
if (ind2 >= MAX_NBD_REQUESTS || !s->requests[ind2].coroutine) {
nbd_channel_error(s, -EINVAL);
return -EINVAL;
}
if (s->reply.handle == handle) {
/* We are done */
return 0;
}
nbd_recv_coroutine_wake_one(&s->requests[ind2]);
}
}
static int coroutine_fn nbd_co_send_request(BlockDriverState *bs,
NBDRequest *request,
QEMUIOVector *qiov)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
int rc, i = -1;
qemu_mutex_lock(&s->requests_lock);
while (s->in_flight == MAX_NBD_REQUESTS ||
(s->state != NBD_CLIENT_CONNECTED && s->in_flight > 0)) {
qemu_co_queue_wait(&s->free_sema, &s->requests_lock);
}
s->in_flight++;
if (s->state != NBD_CLIENT_CONNECTED) {
if (nbd_client_connecting(s)) {
nbd_reconnect_attempt(s);
qemu_co_queue_restart_all(&s->free_sema);
}
if (s->state != NBD_CLIENT_CONNECTED) {
rc = -EIO;
goto err;
}
}
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
if (s->requests[i].coroutine == NULL) {
break;
}
}
assert(i < MAX_NBD_REQUESTS);
s->requests[i].coroutine = qemu_coroutine_self();
s->requests[i].offset = request->from;
s->requests[i].receiving = false;
qemu_mutex_unlock(&s->requests_lock);
qemu_co_mutex_lock(&s->send_mutex);
request->handle = INDEX_TO_HANDLE(s, i);
assert(s->ioc);
if (qiov) {
qio_channel_set_cork(s->ioc, true);
rc = nbd_send_request(s->ioc, request);
if (rc >= 0 && qio_channel_writev_all(s->ioc, qiov->iov, qiov->niov,
NULL) < 0) {
rc = -EIO;
}
qio_channel_set_cork(s->ioc, false);
} else {
rc = nbd_send_request(s->ioc, request);
}
qemu_co_mutex_unlock(&s->send_mutex);
if (rc < 0) {
qemu_mutex_lock(&s->requests_lock);
err:
nbd_channel_error_locked(s, rc);
if (i != -1) {
s->requests[i].coroutine = NULL;
}
s->in_flight--;
qemu_co_queue_next(&s->free_sema);
qemu_mutex_unlock(&s->requests_lock);
}
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 coroutine_fn
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;
ret = nbd_receive_replies(s, handle);
if (ret < 0) {
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;
nbd_recv_coroutines_wake(s);
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 coroutine_fn 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 (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) || iter->ret < 0) {
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:
qemu_mutex_lock(&s->requests_lock);
s->requests[HANDLE_TO_INDEX(s, handle)].coroutine = NULL;
s->in_flight--;
qemu_co_queue_next(&s->free_sema);
qemu_mutex_unlock(&s->requests_lock);
return false;
}
static int coroutine_fn 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 coroutine_fn 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 coroutine_fn 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 coroutine_fn 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_will_reconnect(s));
return ret ? ret : request_ret;
}
static int coroutine_fn nbd_client_co_preadv(BlockDriverState *bs, int64_t offset,
int64_t bytes, QEMUIOVector *qiov,
BdrvRequestFlags 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);
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_will_reconnect(s));
return ret ? ret : request_ret;
}
static int coroutine_fn nbd_client_co_pwritev(BlockDriverState *bs, int64_t offset,
int64_t bytes, QEMUIOVector *qiov,
BdrvRequestFlags 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 coroutine_fn nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
int64_t bytes, BdrvRequestFlags flags)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
NBDRequest request = {
.type = NBD_CMD_WRITE_ZEROES,
.from = offset,
.len = bytes, /* .len is uint32_t actually */
};
assert(bytes <= UINT32_MAX); /* rely on max_pwrite_zeroes */
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 coroutine_fn 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 coroutine_fn nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset,
int64_t bytes)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
NBDRequest request = {
.type = NBD_CMD_TRIM,
.from = offset,
.len = bytes, /* len is uint32_t */
};
assert(bytes <= UINT32_MAX); /* rely on max_pdiscard */
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_will_reconnect(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;
QEMU_LOCK_GUARD(&s->requests_lock);
qio_channel_shutdown(QIO_CHANNEL(s->ioc), QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
s->state = NBD_CLIENT_QUIT;
}
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);
}
/*
* 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;
}
if (socket_address_parse_named_fd(saddr, errp) < 0) {
qapi_free_SocketAddress(saddr);
saddr = NULL;
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 (!qcrypto_tls_creds_check_endpoint(creds,
QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT,
errp)) {
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 = "tls-hostname",
.type = QEMU_OPT_STRING,
.help = "Override hostname for validating TLS x509 certificate",
},
{
.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",
},
{
.name = "open-timeout",
.type = QEMU_OPT_NUMBER,
.help = "In seconds. If zero, the nbd driver tries the connection "
"only once, and fails to open if the connection fails. "
"If non-zero, the nbd driver will repeat connection "
"attempts until successful or until @open-timeout seconds "
"have elapsed. 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;
}
s->tlshostname = g_strdup(qemu_opt_get(opts, "tls-hostname"));
if (!s->tlshostname &&
s->saddr->type == SOCKET_ADDRESS_TYPE_INET) {
s->tlshostname = g_strdup(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);
s->open_timeout = qemu_opt_get_number(opts, "open-timeout", 0);
ret = 0;
error:
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;
s->bs = bs;
qemu_mutex_init(&s->requests_lock);
qemu_co_queue_init(&s->free_sema);
qemu_co_mutex_init(&s->send_mutex);
qemu_co_mutex_init(&s->receive_mutex);
if (!yank_register_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name), errp)) {
return -EEXIST;
}
ret = nbd_process_options(bs, options, errp);
if (ret < 0) {
goto fail;
}
s->conn = nbd_client_connection_new(s->saddr, true, s->export,
s->x_dirty_bitmap, s->tlscreds,
s->tlshostname);
if (s->open_timeout) {
nbd_client_connection_enable_retry(s->conn);
open_timer_init(s, qemu_clock_get_ns(QEMU_CLOCK_REALTIME) +
s->open_timeout * NANOSECONDS_PER_SECOND);
}
s->state = NBD_CLIENT_CONNECTING_WAIT;
ret = nbd_do_establish_connection(bs, true, errp);
if (ret < 0) {
goto fail;
}
/*
* The connect attempt is done, so we no longer need this timer.
* Delete it, because we do not want it to be around when this node
* is drained or closed.
*/
open_timer_del(s);
nbd_client_connection_enable_retry(s->conn);
return 0;
fail:
open_timer_del(s);
nbd_clear_bdrvstate(bs);
return ret;
}
static int coroutine_fn 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)
{
nbd_client_close(bs);
nbd_clear_bdrvstate(bs);
}
/*
* 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",
"tls-hostname",
"server.",
NULL
};
static void nbd_cancel_in_flight(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
reconnect_delay_timer_del(s);
qemu_mutex_lock(&s->requests_lock);
if (s->state == NBD_CLIENT_CONNECTING_WAIT) {
s->state = NBD_CLIENT_CONNECTING_NOWAIT;
}
qemu_mutex_unlock(&s->requests_lock);
nbd_co_establish_connection_cancel(s->conn);
}
static void nbd_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
BDRVNBDState *s = bs->opaque;
/* The open_timer is used only during nbd_open() */
assert(!s->open_timer);
/*
* The reconnect_delay_timer is scheduled in I/O paths when the
* connection is lost, to cancel the reconnection attempt after a
* given time. Once this attempt is done (successfully or not),
* nbd_reconnect_attempt() ensures the timer is deleted before the
* respective I/O request is resumed.
* Since the AioContext can only be changed when a node is drained,
* the reconnect_delay_timer cannot be active here.
*/
assert(!s->reconnect_delay_timer);
if (s->ioc) {
qio_channel_attach_aio_context(s->ioc, new_context);
}
}
static void nbd_detach_aio_context(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
assert(!s->open_timer);
assert(!s->reconnect_delay_timer);
if (s->ioc) {
qio_channel_detach_aio_context(s->ioc);
}
}
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_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,
.bdrv_cancel_in_flight = nbd_cancel_in_flight,
.bdrv_attach_aio_context = nbd_attach_aio_context,
.bdrv_detach_aio_context = nbd_detach_aio_context,
};
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_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,
.bdrv_cancel_in_flight = nbd_cancel_in_flight,
.bdrv_attach_aio_context = nbd_attach_aio_context,
.bdrv_detach_aio_context = nbd_detach_aio_context,
};
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_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,
.bdrv_cancel_in_flight = nbd_cancel_in_flight,
.bdrv_attach_aio_context = nbd_attach_aio_context,
.bdrv_detach_aio_context = nbd_detach_aio_context,
};
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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