virtiofsd: add --fd=FDNUM fd passing option

Although --socket-path=PATH is useful for manual invocations, management
tools typically create the UNIX domain socket themselves and pass it to
the vhost-user device backend.  This way QEMU can be launched
immediately with a valid socket.  No waiting for the vhost-user device
backend is required when fd passing is used.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2019-06-25 17:18:00 +01:00 committed by Dr. David Alan Gilbert
parent eb49d187ef
commit cee8e35d43
3 changed files with 38 additions and 10 deletions

View File

@ -68,6 +68,7 @@ struct fuse_session {
size_t bufsize;
int error;
char *vu_socket_path;
int vu_listen_fd;
int vu_socketfd;
struct fv_VuDev *virtio_dev;
};

View File

@ -2130,6 +2130,7 @@ static const struct fuse_opt fuse_ll_opts[] = {
LL_OPTION("--debug", debug, 1),
LL_OPTION("allow_root", deny_others, 1),
LL_OPTION("--socket-path=%s", vu_socket_path, 0),
LL_OPTION("--fd=%d", vu_listen_fd, 0),
FUSE_OPT_END
};
@ -2147,7 +2148,8 @@ void fuse_lowlevel_help(void)
*/
printf(
" -o allow_root allow access by root\n"
" --socket-path=PATH path for the vhost-user socket\n");
" --socket-path=PATH path for the vhost-user socket\n"
" --fd=FDNUM fd number of vhost-user socket\n");
}
void fuse_session_destroy(struct fuse_session *se)
@ -2191,6 +2193,7 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,
goto out1;
}
se->fd = -1;
se->vu_listen_fd = -1;
se->conn.max_write = UINT_MAX;
se->conn.max_readahead = UINT_MAX;
@ -2212,8 +2215,13 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,
goto out4;
}
if (!se->vu_socket_path) {
fprintf(stderr, "fuse: missing -o vhost_user_socket option\n");
if (!se->vu_socket_path && se->vu_listen_fd < 0) {
fuse_log(FUSE_LOG_ERR, "fuse: missing --socket-path or --fd option\n");
goto out4;
}
if (se->vu_socket_path && se->vu_listen_fd >= 0) {
fuse_log(FUSE_LOG_ERR,
"fuse: --socket-path and --fd cannot be given together\n");
goto out4;
}
@ -2253,7 +2261,7 @@ void fuse_session_unmount(struct fuse_session *se)
int fuse_lowlevel_is_virtio(struct fuse_session *se)
{
return se->vu_socket_path != NULL;
return !!se->virtio_dev;
}
#ifdef linux

View File

@ -638,18 +638,21 @@ int virtio_loop(struct fuse_session *se)
return 0;
}
int virtio_session_mount(struct fuse_session *se)
static int fv_create_listen_socket(struct fuse_session *se)
{
struct sockaddr_un un;
mode_t old_umask;
/* Nothing to do if fd is already initialized */
if (se->vu_listen_fd >= 0) {
return 0;
}
if (strlen(se->vu_socket_path) >= sizeof(un.sun_path)) {
fuse_log(FUSE_LOG_ERR, "Socket path too long\n");
return -1;
}
se->fd = -1;
/*
* Create the Unix socket to communicate with qemu
* based on QEMU's vhost-user-bridge
@ -682,15 +685,31 @@ int virtio_session_mount(struct fuse_session *se)
return -1;
}
se->vu_listen_fd = listen_sock;
return 0;
}
int virtio_session_mount(struct fuse_session *se)
{
int ret;
ret = fv_create_listen_socket(se);
if (ret < 0) {
return ret;
}
se->fd = -1;
fuse_log(FUSE_LOG_INFO, "%s: Waiting for vhost-user socket connection...\n",
__func__);
int data_sock = accept(listen_sock, NULL, NULL);
int data_sock = accept(se->vu_listen_fd, NULL, NULL);
if (data_sock == -1) {
fuse_log(FUSE_LOG_ERR, "vhost socket accept: %m\n");
close(listen_sock);
close(se->vu_listen_fd);
return -1;
}
close(listen_sock);
close(se->vu_listen_fd);
se->vu_listen_fd = -1;
fuse_log(FUSE_LOG_INFO, "%s: Received vhost-user socket connection\n",
__func__);