2 * Serving QEMU block devices via NBD
4 * Copyright (c) 2012 Red Hat, Inc.
6 * Author: Paolo Bonzini <pbonzini@redhat.com>
8 * This work is licensed under the terms of the GNU GPL, version 2 or
9 * later. See the COPYING file in the top-level directory.
12 #include "qemu/osdep.h"
13 #include "sysemu/blockdev.h"
14 #include "sysemu/block-backend.h"
15 #include "hw/block/block.h"
16 #include "qapi/error.h"
17 #include "qapi/qapi-commands-block-export.h"
18 #include "block/nbd.h"
19 #include "io/channel-socket.h"
20 #include "io/net-listener.h"
22 typedef struct NBDServerData {
23 QIONetListener *listener;
24 QCryptoTLSCreds *tlscreds;
26 uint32_t max_connections;
30 static NBDServerData *nbd_server;
31 static bool is_qemu_nbd;
33 static void nbd_update_server_watch(NBDServerData *s);
35 void nbd_server_is_qemu_nbd(bool value)
40 static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
42 nbd_client_put(client);
43 assert(nbd_server->connections > 0);
44 nbd_server->connections--;
45 nbd_update_server_watch(nbd_server);
48 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
51 nbd_server->connections++;
52 nbd_update_server_watch(nbd_server);
54 qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
55 nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz,
56 nbd_blockdev_client_closed);
59 static void nbd_update_server_watch(NBDServerData *s)
61 if (!s->max_connections || s->connections < s->max_connections) {
62 qio_net_listener_set_client_func(s->listener, nbd_accept, NULL, NULL);
64 qio_net_listener_set_client_func(s->listener, NULL, NULL, NULL);
68 static void nbd_server_free(NBDServerData *server)
74 qio_net_listener_disconnect(server->listener);
75 object_unref(OBJECT(server->listener));
76 if (server->tlscreds) {
77 object_unref(OBJECT(server->tlscreds));
79 g_free(server->tlsauthz);
84 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
87 QCryptoTLSCreds *creds;
89 obj = object_resolve_path_component(
90 object_get_objects_root(), id);
92 error_setg(errp, "No TLS credentials with id '%s'",
96 creds = (QCryptoTLSCreds *)
97 object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
99 error_setg(errp, "Object with id '%s' is not TLS credentials",
104 if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
106 "Expecting TLS credentials with a server endpoint");
114 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
115 const char *tls_authz, uint32_t max_connections,
119 error_setg(errp, "NBD server already running");
123 nbd_server = g_new0(NBDServerData, 1);
124 nbd_server->max_connections = max_connections;
125 nbd_server->listener = qio_net_listener_new();
127 qio_net_listener_set_name(nbd_server->listener,
130 if (qio_net_listener_open_sync(nbd_server->listener, addr, 1, errp) < 0) {
135 nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp);
136 if (!nbd_server->tlscreds) {
140 /* TODO SOCKET_ADDRESS_TYPE_FD where fd has AF_INET or AF_INET6 */
141 if (addr->type != SOCKET_ADDRESS_TYPE_INET) {
142 error_setg(errp, "TLS is only supported with IPv4/IPv6");
147 nbd_server->tlsauthz = g_strdup(tls_authz);
149 nbd_update_server_watch(nbd_server);
154 nbd_server_free(nbd_server);
158 void nbd_server_start_options(NbdServerOptions *arg, Error **errp)
160 nbd_server_start(arg->addr, arg->tls_creds, arg->tls_authz,
161 arg->max_connections, errp);
164 void qmp_nbd_server_start(SocketAddressLegacy *addr,
165 bool has_tls_creds, const char *tls_creds,
166 bool has_tls_authz, const char *tls_authz,
167 bool has_max_connections, uint32_t max_connections,
170 SocketAddress *addr_flat = socket_address_flatten(addr);
172 nbd_server_start(addr_flat, tls_creds, tls_authz, max_connections, errp);
173 qapi_free_SocketAddress(addr_flat);
176 int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args,
179 BlockExportOptionsNbd *arg = &exp_args->u.nbd;
180 BlockDriverState *bs = NULL;
181 AioContext *aio_context;
184 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
186 if (!nbd_server && !is_qemu_nbd) {
187 error_setg(errp, "NBD server not running");
191 if (!arg->has_name) {
192 arg->name = exp_args->node_name;
195 if (strlen(arg->name) > NBD_MAX_STRING_SIZE) {
196 error_setg(errp, "export name '%s' too long", arg->name);
200 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) {
201 error_setg(errp, "description '%s' too long", arg->description);
205 if (nbd_export_find(arg->name)) {
206 error_setg(errp, "NBD server already has export named '%s'", arg->name);
210 bs = bdrv_lookup_bs(NULL, exp_args->node_name, errp);
215 aio_context = bdrv_get_aio_context(bs);
216 aio_context_acquire(aio_context);
218 if (!arg->has_writable) {
219 arg->writable = false;
221 if (bdrv_is_read_only(bs) && arg->writable) {
223 error_setg(errp, "Cannot export read-only node as writable");
227 if (!exp_args->has_writethrough) {
228 exp_args->writethrough = false;
231 ret = nbd_export_new(exp, bs, arg->name, arg->description, arg->bitmap,
232 !arg->writable, !arg->writable,
233 exp_args->writethrough, errp);
238 /* The list of named exports has a strong reference to this export now and
239 * our only way of accessing it is through nbd_export_find(), so we can drop
240 * the strong reference that is @exp. */
245 aio_context_release(aio_context);
249 void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp)
252 BlockDriverState *bs;
253 BlockBackend *on_eject_blk;
254 BlockExportOptions *export_opts;
256 bs = bdrv_lookup_bs(arg->device, arg->device, errp);
262 * block-export-add would default to the node-name, but we may have to use
263 * the device name as a default here for compatibility.
265 if (!arg->has_name) {
266 arg->name = arg->device;
269 export_opts = g_new(BlockExportOptions, 1);
270 *export_opts = (BlockExportOptions) {
271 .type = BLOCK_EXPORT_TYPE_NBD,
272 .node_name = g_strdup(bdrv_get_node_name(bs)),
275 .name = g_strdup(arg->name),
276 .has_description = arg->has_description,
277 .description = g_strdup(arg->description),
278 .has_writable = arg->has_writable,
279 .writable = arg->writable,
280 .has_bitmap = arg->has_bitmap,
281 .bitmap = g_strdup(arg->bitmap),
286 * nbd-server-add doesn't complain when a read-only device should be
287 * exported as writable, but simply downgrades it. This is an error with
290 if (bdrv_is_read_only(bs)) {
291 export_opts->u.nbd.has_writable = true;
292 export_opts->u.nbd.writable = false;
295 export = blk_exp_add(export_opts, errp);
301 * nbd-server-add removes the export when the named BlockBackend used for
304 on_eject_blk = blk_by_name(arg->device);
306 nbd_export_set_on_eject_blk(export, on_eject_blk);
310 qapi_free_BlockExportOptions(export_opts);
313 void qmp_nbd_server_remove(const char *name,
314 bool has_mode, NbdServerRemoveMode mode,
318 AioContext *aio_context;
321 error_setg(errp, "NBD server not running");
325 exp = nbd_export_find(name);
327 error_setg(errp, "Export '%s' is not found", name);
332 mode = NBD_SERVER_REMOVE_MODE_SAFE;
335 aio_context = nbd_export_aio_context(exp);
336 aio_context_acquire(aio_context);
337 nbd_export_remove(exp, mode, errp);
338 aio_context_release(aio_context);
341 void qmp_nbd_server_stop(Error **errp)
344 error_setg(errp, "NBD server not running");
348 blk_exp_close_all_type(BLOCK_EXPORT_TYPE_NBD);
350 nbd_server_free(nbd_server);