Fix for hard link creation errors on unionfs.

Since the commit [1] fusefs checks if the inodes of the source and the target
file are identical when creating a hard link. If they differ, an error is
returned. This, however, is a problem when using unionfs. Since hard links
across different file systems are not possible, unionfs copies the source file
from the r/o directory to the writeable directory first, and then creates the
hard link there.

* Install a fusefs2 kernel module which is identical to fusefs except for the
inode check.
* Let /etc/rc.d/mount_uzip unload fusefs if loaded, then load fusefs2.

1. https://cgit.freebsd.org/src/commit/sys/fs/fuse/fuse_vnops.c?h=stable/14&id=0bef4927ea858bb18b6f679bc0a36cff264dc842

build

@@ -45,6 +45,8 @@
 #
 # image       Build the NomadBSD image.
 #
+# modules     Build and install kernel modules from the "modules" directory
+#
 # ports       Build and install all ports defined in build.cfg
 #
 # pkgs        Install all packages from pkg.list
@@ -104,6 +106,7 @@ BUILD_DEPENCIES_LIST_EOF
 )
 
 BUILD_STAGES=$(cat << BUILD_STAGES_END
+build_modules
 install_packages
 install_from_git_repos
 build_setupgui
@@ -1158,6 +1161,25 @@ build_nomadbsd_update()
   umount_chroot_devfs
 }
 
+build_and_install_kmod()
+{
+  chroot "${SYSDIR}" sh -c \
+    "cd $1 && make clean; make && make install" || \
+    bail "Failed to install kernel module $1"
+}
+
+build_modules()
+{
+  local MODULES_DIR="/usr/src/sys/modules"
+
+  for m in modules/*; do
+    [ "$m" = "." -o "$m" = ".." -o ! -d "$m" ] && continue
+    cp -a "$m" "${SYSDIR}/${MODULES_DIR}/" || bail
+    mod=$(basename "$m")
+    build_and_install_kmod "${MODULES_DIR}/${mod}"
+  done
+}
+
 install_nomadbsd_reset()
 {
   local make_opts=""
@@ -1433,6 +1455,7 @@ while [ $# -gt 0 ]; do
   addusergui) build_addusergui;;
   dmconfig)   build_dmconfig;;
   chusr)      build_chusr;;
+  modules)    build_modules;;
   nbsdupdate) build_nomadbsd_update;;
   reset)      install_nomadbsd_reset;;
   src)        install_src_dist;;

build.hlp

@@ -27,6 +27,8 @@ installgui  (Re)build and (re)install nomadbsd-install-gui
 
 kernel      Build a custom kernel using kernel/NOMADBSD
 
+modules     Build and install kernel modules from the "modules" directory
+
 nbsdupdate  Install nomadbsd-update.
 
 pkgcfg      Set up configuration files and users required by installed

config/etc/rc.d/mount_uzip

@@ -102,8 +102,9 @@ do_mount_unionfs()
 		fi
 		[ ! -d "${rwdir}" ] && mkdir -p "${rwdir}"
 	fi
-	if (! kldstat -q -m fusefs && ! kldstat -q -m fuse); then
-		kldload fusefs 2>/dev/null || kldload fuse 2>/dev/null
+	kldstat -q -n fusefs && kldunload fusefs
+	if (! kldstat -q -n fusefs2 && ! kldstat -q -n fusefs); then
+		kldload fusefs2 2>/dev/null || kldload fusefs 2>/dev/null
 	fi
 	unionfs -o cow,max_files=${unionfs_maxfiles} \
 	        -o allow_other,use_ino,suid,nonempty,kernel_cache \

modules/fusefs2/Makefile

@@ -0,0 +1,7 @@
+.PATH: ${SRCTOP}/sys/modules/fusefs2
+KMOD=	fusefs2
+SRCS=	vnode_if.h \
+	fuse_node.c fuse_io.c fuse_device.c fuse_ipc.c fuse_file.c \
+	fuse_vfsops.c fuse_vnops.c fuse_internal.c fuse_main.c
+
+.include <bsd.kmod.mk>

modules/fusefs2/fuse.h

@@ -0,0 +1,95 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 2007-2009 Google Inc.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following disclaimer
+ *   in the documentation and/or other materials provided with the
+ *   distribution.
+ * * Neither the name of Google Inc. nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 
+ * Copyright (C) 2005 Csaba Henk.
+ * All rights reserved.
+ *
+ * Copyright (c) 2019 The FreeBSD Foundation
+ *
+ * Portions of this software were developed by BFF Storage Systems, LLC under
+ * sponsorship from the FreeBSD Foundation.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "fuse_kernel.h"
+
+#define FUSE_DEFAULT_DAEMON_TIMEOUT                60     /* s */
+#define FUSE_MIN_DAEMON_TIMEOUT                    0      /* s */
+#define FUSE_MAX_DAEMON_TIMEOUT                    600    /* s */
+
+/* misc */
+
+SYSCTL_DECL(_vfs_fusefs);
+SYSCTL_DECL(_vfs_fusefs_stats);
+
+/* Fuse locking */
+
+extern struct mtx fuse_mtx;
+#define FUSE_LOCK() fuse_lck_mtx_lock(fuse_mtx)
+#define FUSE_UNLOCK() fuse_lck_mtx_unlock(fuse_mtx)
+
+#define RECTIFY_TDCR(td, cred)			\
+do {						\
+	if (! (td))				\
+		(td) = curthread;		\
+	if (! (cred))				\
+		(cred) = (td)->td_ucred;	\
+} while (0)
+
+#define fuse_lck_mtx_lock(mtx) mtx_lock(&(mtx))
+#define fuse_lck_mtx_unlock(mtx) mtx_unlock(&(mtx))
+
+void fuse_ipc_init(void);
+void fuse_ipc_destroy(void);
+
+int fuse_device_init(void);
+void fuse_device_destroy(void);