Don't send FBT_DESTROY if the FUSE connection is still PENDING. Also

don't attempt to determine the size of the root inode. This is because
we don't need to know the size of directories and FBT_GETATTR will also
cause a deadlock if fuse_unmount(3) is called before the file system
has a chance to process fbufs.

Add corresponding regression test.

ok mpi@

4 files changed, 94 insertions, 14 deletions

diff --git a/regress/lib/libfuse/Makefile b/regress/lib/libfuse/Makefile
index 33f75e66357..a3c73a733b0 100644
--- a/regress/lib/libfuse/Makefile
+++ b/regress/lib/libfuse/Makefile
@@ -1,4 +1,4 @@
-#       $OpenBSD: Makefile,v 1.2 2017/11/16 13:23:13 helg Exp $
+#       $OpenBSD: Makefile,v 1.3 2018/07/17 13:12:08 helg Exp $
 
 REGRESS_TARGETS=  run-fuse-opt-add-opt
 REGRESS_TARGETS+= run-fuse-opt-add-opt-escaped
@@ -7,6 +7,8 @@ REGRESS_TARGETS+= run-fuse-opt-insert-arg
 REGRESS_TARGETS+= run-fuse-opt-match
 REGRESS_TARGETS+= run-fuse-opt-parse
 REGRESS_TARGETS+= run-fuse-parse-cmdline
+REGRESS_TARGETS+= run-fuse-null-check
+REGRESS_TARGETS+= run-fuse-mount
 
 LDFLAGS+= -lfuse
 CLEANFILES= fuse-opt-add-opt
@@ -16,6 +18,8 @@ CLEANFILES+=fuse-opt-insert-arg
 CLEANFILES+=fuse-opt-match
 CLEANFILES+=fuse-opt-parse
 CLEANFILES+=fuse-parse-cmdline
+CLEANFILES+=fuse-null-check
+CLEANFILES+=fuse-mount
 
 .PHONY: ${REGRESS_TARGETS}
 
@@ -33,5 +37,9 @@ run-fuse-opt-parse: fuse-opt-parse
 	./fuse-opt-parse
 run-fuse-parse-cmdline: fuse-parse-cmdline
 	./fuse-parse-cmdline
+run-fuse-null-check: fuse-null-check
+	./fuse-null-check
+run-fuse-mount: fuse-mount
+	./fuse-mount
 
 .include <bsd.regress.mk>
diff --git a/regress/lib/libfuse/fuse-mount.c b/regress/lib/libfuse/fuse-mount.c
new file mode 100644
index 00000000000..25cb562a6e2
--- /dev/null
+++ b/regress/lib/libfuse/fuse-mount.c
@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2018 Helg Bredow <helg@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <fuse.h>
+
+int
+main(int argc, char **argv)
+{
+	struct fuse_chan *fc;
+	const char *dir = "/mnt";
+
+	fc = fuse_mount(dir, NULL);
+	if (fc == NULL)
+		return (1);
+
+	fuse_unmount(dir, fc);
+
+	return (0);
+}
diff --git a/regress/lib/libfuse/fuse-null-check.c b/regress/lib/libfuse/fuse-null-check.c
new file mode 100644
index 00000000000..3d37001bd3f
--- /dev/null
+++ b/regress/lib/libfuse/fuse-null-check.c
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2018 Helg Bredow <helg@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <fuse.h>
+#include <stdlib.h>
+
+int
+main(void)
+{
+	fuse_main(0, NULL, NULL, NULL);
+	fuse_new(NULL, NULL, NULL, 0, NULL);
+	fuse_setup(0, NULL, NULL, 0, NULL, NULL, NULL);
+	fuse_mount(NULL, NULL);
+	fuse_remove_signal_handlers(NULL);
+	fuse_set_signal_handlers(NULL);
+	fuse_get_session(NULL);
+	fuse_is_lib_option(NULL);
+	fuse_loop(NULL);
+	fuse_chan_fd(NULL);
+	fuse_unmount(NULL, NULL);
+	fuse_destroy(NULL);
+	fuse_teardown(NULL, NULL);
+	fuse_invalidate(NULL, NULL);
+
+	return (0);
+}
diff --git a/sys/miscfs/fuse/fuse_vfsops.c b/sys/miscfs/fuse/fuse_vfsops.c
index a7f957f01dc..cf459696944 100644
--- a/sys/miscfs/fuse/fuse_vfsops.c
+++ b/sys/miscfs/fuse/fuse_vfsops.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: fuse_vfsops.c,v 1.41 2018/07/16 16:44:09 helg Exp $ */
+/* $OpenBSD: fuse_vfsops.c,v 1.42 2018/07/17 13:12:08 helg Exp $ */
 /*
  * Copyright (c) 2012-2013 Sylvestre Gallon <ccna.syl@gmail.com>
  *
@@ -157,8 +157,7 @@ fusefs_unmount(struct mount *mp, int mntflags, struct proc *p)
 	if ((error = vflush(mp, NULLVP, flags)))
 		return (error);
 
-	if (fmp->sess_init) {
-		fmp->sess_init = 0;
+	if (fmp->sess_init && fmp->sess_init != PENDING) {
 		fbuf = fb_setup(0, 0, FBT_DESTROY, p);
 
 		error = fb_queue(fmp->dev, fbuf);
@@ -168,6 +167,7 @@ fusefs_unmount(struct mount *mp, int mntflags, struct proc *p)
 
 		fb_delete(fbuf);
 	}
+	fmp->sess_init = 0;
 
 	fuse_device_cleanup(fmp->dev);
 	fuse_device_set_fmp(fmp, 0);
@@ -314,17 +314,18 @@ retry:
 
 	if (ino == FUSE_ROOTINO)
 		nvp->v_flag |= VROOT;
-
-	/*
-	 * Initialise the file size so that file size changes can be
-	 * detected during file operations.
-	 */
-	error = VOP_GETATTR(nvp, &vattr, curproc->p_ucred, curproc);
-	if (error) {
-		vrele(nvp);
-		return (error);
+	else {
+		/*
+		 * Initialise the file size so that file size changes can be
+		 * detected during file operations.
+		 */
+		error = VOP_GETATTR(nvp, &vattr, curproc->p_ucred, curproc);
+		if (error) {
+			vrele(nvp);
+			return (error);
+		}
+		ip->filesize = vattr.va_size;
 	}
-	ip->filesize = vattr.va_size;
 
 	*vpp = nvp;