/* * 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 * * Some parts: * Copyright (C) 2007 Anthony Liguori * * 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; /* * 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);