From: Stefan Hajnoczi <stefa...@redhat.com>
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 <stefa...@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
---
contrib/virtiofsd/fuse_i.h | 1 +
contrib/virtiofsd/fuse_lowlevel.c | 13 ++++++++---
contrib/virtiofsd/fuse_virtio.c | 39 +++++++++++++++++++++++--------
3 files changed, 40 insertions(+), 13 deletions(-)
diff --git a/contrib/virtiofsd/fuse_i.h b/contrib/virtiofsd/fuse_i.h
index 5b6ef09df5..4b718f1aec 100644
--- a/contrib/virtiofsd/fuse_i.h
+++ b/contrib/virtiofsd/fuse_i.h
@@ -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;
};
diff --git a/contrib/virtiofsd/fuse_lowlevel.c
b/contrib/virtiofsd/fuse_lowlevel.c
index b1f44ca17e..da2f151927 100644
--- a/contrib/virtiofsd/fuse_lowlevel.c
+++ b/contrib/virtiofsd/fuse_lowlevel.c
@@ -2077,6 +2077,7 @@ static const struct fuse_opt fuse_ll_opts[] = {
LL_OPTION("allow_root", deny_others, 1),
LL_OPTION("--socket-path=%s", vu_socket_path, 0),
LL_OPTION("vhost_user_socket=%s", vu_socket_path, 0),
+ LL_OPTION("--fd=%d", vu_listen_fd, 0),
FUSE_OPT_END
};
@@ -2095,6 +2096,7 @@ void fuse_lowlevel_help(void)
" -o allow_root allow access by root\n"
" --socket-path=PATH path for the vhost-user socket\n"
" -o vhost_user_socket=PATH path for the vhost-user socket\n"
+" --fd=FDNUM fd number of vhost-user socket\n"
" -o auto_unmount auto unmount on process termination\n");
}
@@ -2134,6 +2136,7 @@ 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;
@@ -2163,8 +2166,12 @@ 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;
}
@@ -2205,7 +2212,7 @@ 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
diff --git a/contrib/virtiofsd/fuse_virtio.c b/contrib/virtiofsd/fuse_virtio.c
index f52d815596..cc393c3cac 100644
--- a/contrib/virtiofsd/fuse_virtio.c
+++ b/contrib/virtiofsd/fuse_virtio.c
@@ -635,21 +635,20 @@ 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;
+ /* 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;
}
- /*
- * Poison the fuse FD so we spot if we accidentally use it;
- * DO NOT check for this value, check for fuse_lowlevel_is_virtio()
- */
- se->fd = 0xdaff0d11;
-
/*
* Create the Unix socket to communicate with qemu
* based on QEMU's vhost-user-bridge
@@ -675,15 +674,35 @@ 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;
+ }
+
+ /*
+ * Poison the fuse FD so we spot if we accidentally use it;
+ * DO NOT check for this value, check fuse_lowlevel_is_virtio()
+ */
+ se->fd = 0xdaff0d11;
+
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__);
se->vu_socketfd = data_sock;
--
2.23.0
