diff --git a/sbin/mount_fusefs/mount_fusefs.c b/sbin/mount_fusefs/mount_fusefs.c
--- a/sbin/mount_fusefs/mount_fusefs.c
+++ b/sbin/mount_fusefs/mount_fusefs.c
@@ -34,10 +34,12 @@
  */
 
 #include <sys/param.h>
+#include <sys/event.h>
 #include <sys/mount.h>
-#include <sys/uio.h>
 #include <sys/stat.h>
 #include <sys/sysctl.h>
+#include <sys/uio.h>
+#include <sys/user.h>
 
 #include <err.h>
 #include <stdio.h>
@@ -112,6 +114,112 @@
 };
 
 #define DEFAULT_MOUNT_FLAGS ALTF_PRIVATE
+#define AUTO_UNMOUNT_OPTION 128
+
+static int
+resolve_pid(pid_t pid, struct kinfo_proc *out)
+{
+	int mib[4];
+	size_t size = sizeof(struct kinfo_proc);
+
+	mib[0] = CTL_KERN;
+	mib[1] = KERN_PROC;
+	mib[2] = KERN_PROC_PID;
+	mib[3] = pid;
+	return (sysctl(mib, 4, out, &size, NULL, 0));
+}
+
+static int
+auto_unmount_main(const char *mountpoint, const char *args)
+{
+	pid_t parent_pid;
+	struct timeval parent_start;
+	fsid_t fsid;
+	int parsed;
+	struct kinfo_proc proc_info;
+	struct statfs stat_buf;
+	int kq;
+	struct kevent kev;
+
+	/*
+	 * The caller should pass the following info for auto unmount to work:
+	 * parent's PID to monitor
+	 * parent PID's starting time to avoid races
+	 * fsid values to let us be sure we're unmounting the right FS
+	 */
+	parsed = sscanf(args, "%d,%ld,%ld,%d,%d", &parent_pid,
+	    &parent_start.tv_sec, &parent_start.tv_usec,
+	    &fsid.val[0], &fsid.val[1]);
+	if (parsed != 5) {
+		warnx("fail to parse auto-unmount args");
+		return (1);
+	}
+
+	kq = kqueue();
+	if (kq == -1) {
+		warn("fail to create kqueue");
+		return (1);
+	}
+
+	EV_SET(&kev, parent_pid, EVFILT_PROC, EV_ADD | EV_ENABLE, NOTE_EXIT,
+	    0, NULL);
+	if (kevent(kq, &kev, 1, NULL, 0, NULL) == -1) {
+		warn("fail to setup process monitor");
+		close(kq);
+		return (1);
+	}
+
+	/* If the process is already gone, unmount immediately and exit. */
+	if (resolve_pid(parent_pid, &proc_info) != 0)
+		goto unmount;
+
+	/*
+	 * It might be a different process with the same PID, so
+	 * check starting times.
+	 */
+	if (proc_info.ki_start.tv_sec != parent_start.tv_sec ||
+	    proc_info.ki_start.tv_usec != parent_start.tv_usec)
+		goto unmount;
+
+	/* Wait for the parent process to die. */
+	if (kevent(kq, NULL, 0, &kev, 1, NULL) == -1) {
+		warn("failure while waiting for process to die");
+		close(kq)
+		return (1);
+	}
+	if ((kev.fflags & NOTE_EXIT) == 0) {
+		warnx("unknown event while waiting for process to die");
+		close(kq);
+		return (1);
+	}
+
+unmount:
+	close(kq);
+
+	if (statfs(mountpoint, &stat_buf) != 0) {
+		warn("fail to statfs the mountpoint");
+		return (1);
+	}
+	/*
+	 * Do not unmount if fsid's differ - otherwise we'll unmount
+	 * someone's else FS.
+	 */
+	if (stat_buf.f_fsid.val[0] != fsid.val[0] ||
+	    stat_buf.f_fsid.val[1] != fsid.val[1])
+		return (1);
+	/* Refuse to unmount anything other than fuse. */
+	if (strncmp(stat_buf.f_fstypename, "fusefs", 6))
+		return (1);
+	/*
+	 * For usermount case we should only unmount filesystems
+	 * mounted by the same user.
+	 */
+	if (stat_buf.f_owner != proc_info.ki_ruid)
+		return (1);
+
+	unmount(mountpoint, 0);
+	return (0);
+}
 
 int
 main(int argc, char *argv[])
@@ -136,12 +244,14 @@
 		{"mountpath", required_argument, NULL, 'm'},
 		{"version", no_argument, NULL, 'V'},
 		{"help", no_argument, NULL, 'h'},
+		{"auto-unmount", required_argument, NULL, AUTO_UNMOUNT_OPTION},
 		{0,0,0,0}
 	};
-	int pid = 0;
+	pid_t pid = 0;
 	int fd = -1, fdx;
 	char *ep;
 	char *daemon_str = NULL, *daemon_opts = NULL;
+	char *auto_unmount_args = NULL;
 
 	/*
 	 * We want a parsing routine which is not sensitive to
@@ -238,6 +348,11 @@
 		case 'V':
 			showversion();
 			break;
+		case AUTO_UNMOUNT_OPTION:
+			if (auto_unmount_args)
+				errx(1, "auto-unmount args specified inconsistently");
+			auto_unmount_args = optarg;
+			break;
 		case '\0':
 			break;
 		case '?':
@@ -277,6 +392,9 @@
 	if (! (dev && dir))
 		errx(1, "missing special and/or mountpoint");
 
+	if (auto_unmount_args)
+		return (auto_unmount_main(dir, auto_unmount_args));
+
 	for (mo = mopts; mo->m_flag; ++mo) {
 		if (altflags & mo->m_flag) {
 			int iov_done = 0;