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-rw-r--r--block/monitor/block-hmp-cmds.c2
-rw-r--r--blockdev-nbd.c33
-rw-r--r--include/block/nbd.h3
-rw-r--r--qapi/block-export.json10
-rw-r--r--storage-daemon/qemu-storage-daemon.c4
5 files changed, 39 insertions, 13 deletions
diff --git a/block/monitor/block-hmp-cmds.c b/block/monitor/block-hmp-cmds.c
index fb632b1189..662b7f7d00 100644
--- a/block/monitor/block-hmp-cmds.c
+++ b/block/monitor/block-hmp-cmds.c
@@ -411,7 +411,7 @@ void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
goto exit;
}
- nbd_server_start(addr, NULL, NULL, &local_err);
+ nbd_server_start(addr, NULL, NULL, 0, &local_err);
qapi_free_SocketAddress(addr);
if (local_err != NULL) {
goto exit;
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 7bcca105f9..41d5542987 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -23,23 +23,41 @@ typedef struct NBDServerData {
QIONetListener *listener;
QCryptoTLSCreds *tlscreds;
char *tlsauthz;
+ uint32_t max_connections;
+ uint32_t connections;
} NBDServerData;
static NBDServerData *nbd_server;
+static void nbd_update_server_watch(NBDServerData *s);
+
static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
{
nbd_client_put(client);
+ assert(nbd_server->connections > 0);
+ nbd_server->connections--;
+ nbd_update_server_watch(nbd_server);
}
static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
gpointer opaque)
{
+ nbd_server->connections++;
+ nbd_update_server_watch(nbd_server);
+
qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz,
nbd_blockdev_client_closed);
}
+static void nbd_update_server_watch(NBDServerData *s)
+{
+ if (!s->max_connections || s->connections < s->max_connections) {
+ qio_net_listener_set_client_func(s->listener, nbd_accept, NULL, NULL);
+ } else {
+ qio_net_listener_set_client_func(s->listener, NULL, NULL, NULL);
+ }
+}
static void nbd_server_free(NBDServerData *server)
{
@@ -88,7 +106,8 @@ static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
void nbd_server_start(SocketAddress *addr, const char *tls_creds,
- const char *tls_authz, Error **errp)
+ const char *tls_authz, uint32_t max_connections,
+ Error **errp)
{
if (nbd_server) {
error_setg(errp, "NBD server already running");
@@ -96,6 +115,7 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,
}
nbd_server = g_new0(NBDServerData, 1);
+ nbd_server->max_connections = max_connections;
nbd_server->listener = qio_net_listener_new();
qio_net_listener_set_name(nbd_server->listener,
@@ -120,10 +140,7 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,
nbd_server->tlsauthz = g_strdup(tls_authz);
- qio_net_listener_set_client_func(nbd_server->listener,
- nbd_accept,
- NULL,
- NULL);
+ nbd_update_server_watch(nbd_server);
return;
@@ -134,17 +151,19 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,
void nbd_server_start_options(NbdServerOptions *arg, Error **errp)
{
- nbd_server_start(arg->addr, arg->tls_creds, arg->tls_authz, errp);
+ nbd_server_start(arg->addr, arg->tls_creds, arg->tls_authz,
+ arg->max_connections, errp);
}
void qmp_nbd_server_start(SocketAddressLegacy *addr,
bool has_tls_creds, const char *tls_creds,
bool has_tls_authz, const char *tls_authz,
+ bool has_max_connections, uint32_t max_connections,
Error **errp)
{
SocketAddress *addr_flat = socket_address_flatten(addr);
- nbd_server_start(addr_flat, tls_creds, tls_authz, errp);
+ nbd_server_start(addr_flat, tls_creds, tls_authz, max_connections, errp);
qapi_free_SocketAddress(addr_flat);
}
diff --git a/include/block/nbd.h b/include/block/nbd.h
index f55f5b710b..acccdb3180 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -354,7 +354,8 @@ void nbd_client_get(NBDClient *client);
void nbd_client_put(NBDClient *client);
void nbd_server_start(SocketAddress *addr, const char *tls_creds,
- const char *tls_authz, Error **errp);
+ const char *tls_authz, uint32_t max_connections,
+ Error **errp);
void nbd_server_start_options(NbdServerOptions *arg, Error **errp);
/* nbd_read
diff --git a/qapi/block-export.json b/qapi/block-export.json
index 5890a94219..8aa8a01fa6 100644
--- a/qapi/block-export.json
+++ b/qapi/block-export.json
@@ -20,13 +20,16 @@
# is only resolved at time of use, so can be deleted and
# recreated on the fly while the NBD server is active.
# If missing, it will default to denying access (since 4.0).
+# @max-connections: The maximum number of connections to allow at the same
+# time, 0 for unlimited. (since 5.2; default: 0)
#
# Since: 4.2
##
{ 'struct': 'NbdServerOptions',
'data': { 'addr': 'SocketAddress',
'*tls-creds': 'str',
- '*tls-authz': 'str'} }
+ '*tls-authz': 'str',
+ '*max-connections': 'uint32' } }
##
# @nbd-server-start:
@@ -46,6 +49,8 @@
# is only resolved at time of use, so can be deleted and
# recreated on the fly while the NBD server is active.
# If missing, it will default to denying access (since 4.0).
+# @max-connections: The maximum number of connections to allow at the same
+# time, 0 for unlimited. (since 5.2; default: 0)
#
# Returns: error if the server is already running.
#
@@ -54,7 +59,8 @@
{ 'command': 'nbd-server-start',
'data': { 'addr': 'SocketAddressLegacy',
'*tls-creds': 'str',
- '*tls-authz': 'str'} }
+ '*tls-authz': 'str',
+ '*max-connections': 'uint32' } }
##
# @BlockExportOptionsNbd:
diff --git a/storage-daemon/qemu-storage-daemon.c b/storage-daemon/qemu-storage-daemon.c
index b6f678d3ab..0fcab6ed2d 100644
--- a/storage-daemon/qemu-storage-daemon.c
+++ b/storage-daemon/qemu-storage-daemon.c
@@ -101,9 +101,9 @@ static void help(void)
" configure a QMP monitor\n"
"\n"
" --nbd-server addr.type=inet,addr.host=<host>,addr.port=<port>\n"
-" [,tls-creds=<id>][,tls-authz=<id>]\n"
+" [,tls-creds=<id>][,tls-authz=<id>][,max-connections=<n>]\n"
" --nbd-server addr.type=unix,addr.path=<path>\n"
-" [,tls-creds=<id>][,tls-authz=<id>]\n"
+" [,tls-creds=<id>][,tls-authz=<id>][,max-connections=<n>]\n"
" start an NBD server for exporting block nodes\n"
"\n"
" --object help list object types that can be added\n"
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-11-21 17:00:00 +0100