| /* |
| * QEMU Block driver for NBD |
| * |
| * Copyright (C) 2008 Bull S.A.S. |
| * Author: Laurent Vivier <Laurent.Vivier@bull.net> |
| * |
| * Some parts: |
| * Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws> |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| * THE SOFTWARE. |
| */ |
| |
| #include "qemu-common.h" |
| #include "block/nbd.h" |
| #include "qemu/uri.h" |
| #include "block/block_int.h" |
| #include "qemu/module.h" |
| #include "qemu/sockets.h" |
| #include "qapi/qmp/qjson.h" |
| #include "qapi/qmp/qint.h" |
| |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| #define EN_OPTSTR ":exportname=" |
| |
| /* #define DEBUG_NBD */ |
| |
| #if defined(DEBUG_NBD) |
| #define logout(fmt, ...) \ |
| fprintf(stderr, "nbd\t%-24s" fmt, __func__, ##__VA_ARGS__) |
| #else |
| #define logout(fmt, ...) ((void)0) |
| #endif |
| |
| #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 BDRVNBDState { |
| int sock; |
| uint32_t nbdflags; |
| off_t size; |
| size_t blocksize; |
| |
| CoMutex send_mutex; |
| CoMutex free_sema; |
| Coroutine *send_coroutine; |
| int in_flight; |
| |
| Coroutine *recv_coroutine[MAX_NBD_REQUESTS]; |
| struct nbd_reply reply; |
| |
| bool is_unix; |
| QemuOpts *socket_opts; |
| |
| char *export_name; /* An NBD server may export several devices */ |
| } BDRVNBDState; |
| |
| 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 (!strcmp(uri->scheme, "nbd")) { |
| is_unix = false; |
| } else if (!strcmp(uri->scheme, "nbd+tcp")) { |
| is_unix = false; |
| } else if (!strcmp(uri->scheme, "nbd+unix")) { |
| is_unix = true; |
| } else { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| p = uri->path ? uri->path : "/"; |
| p += strspn(p, "/"); |
| if (p[0]) { |
| qdict_put(options, "export", qstring_from_str(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(options, "path", qstring_from_str(qp->p[0].value)); |
| } else { |
| /* nbd[+tcp]://host[:port]/export */ |
| if (!uri->server) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| qdict_put(options, "host", qstring_from_str(uri->server)); |
| if (uri->port) { |
| char* port_str = g_strdup_printf("%d", uri->port); |
| qdict_put(options, "port", qstring_from_str(port_str)); |
| g_free(port_str); |
| } |
| } |
| |
| out: |
| if (qp) { |
| query_params_free(qp); |
| } |
| uri_free(uri); |
| return ret; |
| } |
| |
| static void nbd_parse_filename(const char *filename, QDict *options, |
| Error **errp) |
| { |
| char *file; |
| char *export_name; |
| const char *host_spec; |
| const char *unixpath; |
| |
| if (qdict_haskey(options, "host") |
| || qdict_haskey(options, "port") |
| || qdict_haskey(options, "path")) |
| { |
| error_setg(errp, "host/port/path and a file name may not be specified " |
| "at the same time"); |
| 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) { |
| goto out; |
| } |
| export_name[0] = 0; /* truncate 'file' */ |
| export_name += strlen(EN_OPTSTR); |
| |
| qdict_put(options, "export", qstring_from_str(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:'"); |
| goto out; |
| } |
| |
| if (!*host_spec) { |
| goto out; |
| } |
| |
| /* are we a UNIX or TCP socket? */ |
| if (strstart(host_spec, "unix:", &unixpath)) { |
| qdict_put(options, "path", qstring_from_str(unixpath)); |
| } else { |
| InetSocketAddress *addr = NULL; |
| |
| addr = inet_parse(host_spec, errp); |
| if (error_is_set(errp)) { |
| goto out; |
| } |
| |
| qdict_put(options, "host", qstring_from_str(addr->host)); |
| qdict_put(options, "port", qstring_from_str(addr->port)); |
| qapi_free_InetSocketAddress(addr); |
| } |
| |
| out: |
| g_free(file); |
| } |
| |
| static int nbd_config(BDRVNBDState *s, QDict *options) |
| { |
| Error *local_err = NULL; |
| |
| if (qdict_haskey(options, "path")) { |
| if (qdict_haskey(options, "host")) { |
| qerror_report(ERROR_CLASS_GENERIC_ERROR, "path and host may not " |
| "be used at the same time."); |
| return -EINVAL; |
| } |
| s->is_unix = true; |
| } else if (qdict_haskey(options, "host")) { |
| s->is_unix = false; |
| } else { |
| return -EINVAL; |
| } |
| |
| s->socket_opts = qemu_opts_create_nofail(&socket_optslist); |
| |
| qemu_opts_absorb_qdict(s->socket_opts, options, &local_err); |
| if (error_is_set(&local_err)) { |
| qerror_report_err(local_err); |
| error_free(local_err); |
| return -EINVAL; |
| } |
| |
| if (!qemu_opt_get(s->socket_opts, "port")) { |
| qemu_opt_set_number(s->socket_opts, "port", NBD_DEFAULT_PORT); |
| } |
| |
| s->export_name = g_strdup(qdict_get_try_str(options, "export")); |
| if (s->export_name) { |
| qdict_del(options, "export"); |
| } |
| |
| return 0; |
| } |
| |
| |
| static void nbd_coroutine_start(BDRVNBDState *s, struct nbd_request *request) |
| { |
| int i; |
| |
| /* Poor man semaphore. The free_sema is locked when no other request |
| * can be accepted, and unlocked after receiving one reply. */ |
| if (s->in_flight >= MAX_NBD_REQUESTS - 1) { |
| qemu_co_mutex_lock(&s->free_sema); |
| assert(s->in_flight < MAX_NBD_REQUESTS); |
| } |
| s->in_flight++; |
| |
| for (i = 0; i < MAX_NBD_REQUESTS; i++) { |
| if (s->recv_coroutine[i] == NULL) { |
| s->recv_coroutine[i] = qemu_coroutine_self(); |
| break; |
| } |
| } |
| |
| assert(i < MAX_NBD_REQUESTS); |
| request->handle = INDEX_TO_HANDLE(s, i); |
| } |
| |
| static int nbd_have_request(void *opaque) |
| { |
| BDRVNBDState *s = opaque; |
| |
| return s->in_flight > 0; |
| } |
| |
| static void nbd_reply_ready(void *opaque) |
| { |
| BDRVNBDState *s = opaque; |
| uint64_t i; |
| int ret; |
| |
| if (s->reply.handle == 0) { |
| /* No reply already in flight. Fetch a header. It is possible |
| * that another thread has done the same thing in parallel, so |
| * the socket is not readable anymore. |
| */ |
| ret = nbd_receive_reply(s->sock, &s->reply); |
| if (ret == -EAGAIN) { |
| return; |
| } |
| if (ret < 0) { |
| s->reply.handle = 0; |
| goto fail; |
| } |
| } |
| |
| /* There's no need for a mutex on the receive side, because the |
| * handler acts as a synchronization point and ensures that only |
| * one coroutine is called until the reply finishes. */ |
| i = HANDLE_TO_INDEX(s, s->reply.handle); |
| if (i >= MAX_NBD_REQUESTS) { |
| goto fail; |
| } |
| |
| if (s->recv_coroutine[i]) { |
| qemu_coroutine_enter(s->recv_coroutine[i], NULL); |
| return; |
| } |
| |
| fail: |
| for (i = 0; i < MAX_NBD_REQUESTS; i++) { |
| if (s->recv_coroutine[i]) { |
| qemu_coroutine_enter(s->recv_coroutine[i], NULL); |
| } |
| } |
| } |
| |
| static void nbd_restart_write(void *opaque) |
| { |
| BDRVNBDState *s = opaque; |
| qemu_coroutine_enter(s->send_coroutine, NULL); |
| } |
| |
| static int nbd_co_send_request(BDRVNBDState *s, struct nbd_request *request, |
| QEMUIOVector *qiov, int offset) |
| { |
| int rc, ret; |
| |
| qemu_co_mutex_lock(&s->send_mutex); |
| s->send_coroutine = qemu_coroutine_self(); |
| qemu_aio_set_fd_handler(s->sock, nbd_reply_ready, nbd_restart_write, |
| nbd_have_request, s); |
| if (qiov) { |
| if (!s->is_unix) { |
| socket_set_cork(s->sock, 1); |
| } |
| rc = nbd_send_request(s->sock, request); |
| if (rc >= 0) { |
| ret = qemu_co_sendv(s->sock, qiov->iov, qiov->niov, |
| offset, request->len); |
| if (ret != request->len) { |
| rc = -EIO; |
| } |
| } |
| if (!s->is_unix) { |
| socket_set_cork(s->sock, 0); |
| } |
| } else { |
| rc = nbd_send_request(s->sock, request); |
| } |
| qemu_aio_set_fd_handler(s->sock, nbd_reply_ready, NULL, |
| nbd_have_request, s); |
| s->send_coroutine = NULL; |
| qemu_co_mutex_unlock(&s->send_mutex); |
| return rc; |
| } |
| |
| static void nbd_co_receive_reply(BDRVNBDState *s, struct nbd_request *request, |
| struct nbd_reply *reply, |
| QEMUIOVector *qiov, int offset) |
| { |
| int ret; |
| |
| /* Wait until we're woken up by the read handler. TODO: perhaps |
| * peek at the next reply and avoid yielding if it's ours? */ |
| qemu_coroutine_yield(); |
| *reply = s->reply; |
| if (reply->handle != request->handle) { |
| reply->error = EIO; |
| } else { |
| if (qiov && reply->error == 0) { |
| ret = qemu_co_recvv(s->sock, qiov->iov, qiov->niov, |
| offset, request->len); |
| if (ret != request->len) { |
| reply->error = EIO; |
| } |
| } |
| |
| /* Tell the read handler to read another header. */ |
| s->reply.handle = 0; |
| } |
| } |
| |
| static void nbd_coroutine_end(BDRVNBDState *s, struct nbd_request *request) |
| { |
| int i = HANDLE_TO_INDEX(s, request->handle); |
| s->recv_coroutine[i] = NULL; |
| if (s->in_flight-- == MAX_NBD_REQUESTS) { |
| qemu_co_mutex_unlock(&s->free_sema); |
| } |
| } |
| |
| static int nbd_establish_connection(BlockDriverState *bs) |
| { |
| BDRVNBDState *s = bs->opaque; |
| int sock; |
| int ret; |
| off_t size; |
| size_t blocksize; |
| |
| if (s->is_unix) { |
| sock = unix_socket_outgoing(qemu_opt_get(s->socket_opts, "path")); |
| } else { |
| sock = tcp_socket_outgoing_opts(s->socket_opts); |
| if (sock >= 0) { |
| socket_set_nodelay(sock); |
| } |
| } |
| |
| /* Failed to establish connection */ |
| if (sock < 0) { |
| logout("Failed to establish connection to NBD server\n"); |
| return -errno; |
| } |
| |
| /* NBD handshake */ |
| ret = nbd_receive_negotiate(sock, s->export_name, &s->nbdflags, &size, |
| &blocksize); |
| if (ret < 0) { |
| logout("Failed to negotiate with the NBD server\n"); |
| closesocket(sock); |
| return ret; |
| } |
| |
| /* Now that we're connected, set the socket to be non-blocking and |
| * kick the reply mechanism. */ |
| qemu_set_nonblock(sock); |
| qemu_aio_set_fd_handler(sock, nbd_reply_ready, NULL, |
| nbd_have_request, s); |
| |
| s->sock = sock; |
| s->size = size; |
| s->blocksize = blocksize; |
| |
| logout("Established connection with NBD server\n"); |
| return 0; |
| } |
| |
| static void nbd_teardown_connection(BlockDriverState *bs) |
| { |
| BDRVNBDState *s = bs->opaque; |
| struct nbd_request request; |
| |
| request.type = NBD_CMD_DISC; |
| request.from = 0; |
| request.len = 0; |
| nbd_send_request(s->sock, &request); |
| |
| qemu_aio_set_fd_handler(s->sock, NULL, NULL, NULL, NULL); |
| closesocket(s->sock); |
| } |
| |
| static int nbd_open(BlockDriverState *bs, QDict *options, int flags) |
| { |
| BDRVNBDState *s = bs->opaque; |
| int result; |
| |
| qemu_co_mutex_init(&s->send_mutex); |
| qemu_co_mutex_init(&s->free_sema); |
| |
| /* Pop the config into our state object. Exit if invalid. */ |
| result = nbd_config(s, options); |
| if (result != 0) { |
| return result; |
| } |
| |
| /* establish TCP connection, return error if it fails |
| * TODO: Configurable retry-until-timeout behaviour. |
| */ |
| result = nbd_establish_connection(bs); |
| |
| return result; |
| } |
| |
| static int nbd_co_readv_1(BlockDriverState *bs, int64_t sector_num, |
| int nb_sectors, QEMUIOVector *qiov, |
| int offset) |
| { |
| BDRVNBDState *s = bs->opaque; |
| struct nbd_request request; |
| struct nbd_reply reply; |
| ssize_t ret; |
| |
| request.type = NBD_CMD_READ; |
| request.from = sector_num * 512; |
| request.len = nb_sectors * 512; |
| |
| nbd_coroutine_start(s, &request); |
| ret = nbd_co_send_request(s, &request, NULL, 0); |
| if (ret < 0) { |
| reply.error = -ret; |
| } else { |
| nbd_co_receive_reply(s, &request, &reply, qiov, offset); |
| } |
| nbd_coroutine_end(s, &request); |
| return -reply.error; |
| |
| } |
| |
| static int nbd_co_writev_1(BlockDriverState *bs, int64_t sector_num, |
| int nb_sectors, QEMUIOVector *qiov, |
| int offset) |
| { |
| BDRVNBDState *s = bs->opaque; |
| struct nbd_request request; |
| struct nbd_reply reply; |
| ssize_t ret; |
| |
| request.type = NBD_CMD_WRITE; |
| if (!bdrv_enable_write_cache(bs) && (s->nbdflags & NBD_FLAG_SEND_FUA)) { |
| request.type |= NBD_CMD_FLAG_FUA; |
| } |
| |
| request.from = sector_num * 512; |
| request.len = nb_sectors * 512; |
| |
| nbd_coroutine_start(s, &request); |
| ret = nbd_co_send_request(s, &request, qiov, offset); |
| if (ret < 0) { |
| reply.error = -ret; |
| } else { |
| nbd_co_receive_reply(s, &request, &reply, NULL, 0); |
| } |
| nbd_coroutine_end(s, &request); |
| return -reply.error; |
| } |
| |
| /* qemu-nbd has a limit of slightly less than 1M per request. Try to |
| * remain aligned to 4K. */ |
| #define NBD_MAX_SECTORS 2040 |
| |
| static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num, |
| int nb_sectors, QEMUIOVector *qiov) |
| { |
| int offset = 0; |
| int ret; |
| while (nb_sectors > NBD_MAX_SECTORS) { |
| ret = nbd_co_readv_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset); |
| if (ret < 0) { |
| return ret; |
| } |
| offset += NBD_MAX_SECTORS * 512; |
| sector_num += NBD_MAX_SECTORS; |
| nb_sectors -= NBD_MAX_SECTORS; |
| } |
| return nbd_co_readv_1(bs, sector_num, nb_sectors, qiov, offset); |
| } |
| |
| static int nbd_co_writev(BlockDriverState *bs, int64_t sector_num, |
| int nb_sectors, QEMUIOVector *qiov) |
| { |
| int offset = 0; |
| int ret; |
| while (nb_sectors > NBD_MAX_SECTORS) { |
| ret = nbd_co_writev_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset); |
| if (ret < 0) { |
| return ret; |
| } |
| offset += NBD_MAX_SECTORS * 512; |
| sector_num += NBD_MAX_SECTORS; |
| nb_sectors -= NBD_MAX_SECTORS; |
| } |
| return nbd_co_writev_1(bs, sector_num, nb_sectors, qiov, offset); |
| } |
| |
| static int nbd_co_flush(BlockDriverState *bs) |
| { |
| BDRVNBDState *s = bs->opaque; |
| struct nbd_request request; |
| struct nbd_reply reply; |
| ssize_t ret; |
| |
| if (!(s->nbdflags & NBD_FLAG_SEND_FLUSH)) { |
| return 0; |
| } |
| |
| request.type = NBD_CMD_FLUSH; |
| if (s->nbdflags & NBD_FLAG_SEND_FUA) { |
| request.type |= NBD_CMD_FLAG_FUA; |
| } |
| |
| request.from = 0; |
| request.len = 0; |
| |
| nbd_coroutine_start(s, &request); |
| ret = nbd_co_send_request(s, &request, NULL, 0); |
| if (ret < 0) { |
| reply.error = -ret; |
| } else { |
| nbd_co_receive_reply(s, &request, &reply, NULL, 0); |
| } |
| nbd_coroutine_end(s, &request); |
| return -reply.error; |
| } |
| |
| static int nbd_co_discard(BlockDriverState *bs, int64_t sector_num, |
| int nb_sectors) |
| { |
| BDRVNBDState *s = bs->opaque; |
| struct nbd_request request; |
| struct nbd_reply reply; |
| ssize_t ret; |
| |
| if (!(s->nbdflags & NBD_FLAG_SEND_TRIM)) { |
| return 0; |
| } |
| request.type = NBD_CMD_TRIM; |
| request.from = sector_num * 512; |
| request.len = nb_sectors * 512; |
| |
| nbd_coroutine_start(s, &request); |
| ret = nbd_co_send_request(s, &request, NULL, 0); |
| if (ret < 0) { |
| reply.error = -ret; |
| } else { |
| nbd_co_receive_reply(s, &request, &reply, NULL, 0); |
| } |
| nbd_coroutine_end(s, &request); |
| return -reply.error; |
| } |
| |
| static void nbd_close(BlockDriverState *bs) |
| { |
| BDRVNBDState *s = bs->opaque; |
| g_free(s->export_name); |
| qemu_opts_del(s->socket_opts); |
| |
| nbd_teardown_connection(bs); |
| } |
| |
| static int64_t nbd_getlength(BlockDriverState *bs) |
| { |
| BDRVNBDState *s = bs->opaque; |
| |
| return s->size; |
| } |
| |
| static BlockDriver bdrv_nbd = { |
| .format_name = "nbd", |
| .protocol_name = "nbd", |
| .instance_size = sizeof(BDRVNBDState), |
| .bdrv_parse_filename = nbd_parse_filename, |
| .bdrv_file_open = nbd_open, |
| .bdrv_co_readv = nbd_co_readv, |
| .bdrv_co_writev = nbd_co_writev, |
| .bdrv_close = nbd_close, |
| .bdrv_co_flush_to_os = nbd_co_flush, |
| .bdrv_co_discard = nbd_co_discard, |
| .bdrv_getlength = nbd_getlength, |
| }; |
| |
| static BlockDriver bdrv_nbd_tcp = { |
| .format_name = "nbd", |
| .protocol_name = "nbd+tcp", |
| .instance_size = sizeof(BDRVNBDState), |
| .bdrv_parse_filename = nbd_parse_filename, |
| .bdrv_file_open = nbd_open, |
| .bdrv_co_readv = nbd_co_readv, |
| .bdrv_co_writev = nbd_co_writev, |
| .bdrv_close = nbd_close, |
| .bdrv_co_flush_to_os = nbd_co_flush, |
| .bdrv_co_discard = nbd_co_discard, |
| .bdrv_getlength = nbd_getlength, |
| }; |
| |
| static BlockDriver bdrv_nbd_unix = { |
| .format_name = "nbd", |
| .protocol_name = "nbd+unix", |
| .instance_size = sizeof(BDRVNBDState), |
| .bdrv_parse_filename = nbd_parse_filename, |
| .bdrv_file_open = nbd_open, |
| .bdrv_co_readv = nbd_co_readv, |
| .bdrv_co_writev = nbd_co_writev, |
| .bdrv_close = nbd_close, |
| .bdrv_co_flush_to_os = nbd_co_flush, |
| .bdrv_co_discard = nbd_co_discard, |
| .bdrv_getlength = nbd_getlength, |
| }; |
| |
| 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); |