From 7435939a76a8fe102570603cc9f5118e372dd7e2 Mon Sep 17 00:00:00 2001
From: smh <smh@ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f>
Date: Wed, 6 Jan 2016 09:56:06 +0000
Subject: [PATCH] MFC: r292266 & r292947

Add flag to disable inital reboot(8) userland sync

Sponsored by:	Multiplay


git-svn-id: svn://svn.freebsd.org/base/stable/10@293232 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
---
 sbin/reboot/reboot.8 | 19 +++++++++++++++----
 sbin/reboot/reboot.c | 12 +++++++++---
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/sbin/reboot/reboot.8 b/sbin/reboot/reboot.8
index 13d7098ae..84dd887aa 100644
--- a/sbin/reboot/reboot.8
+++ b/sbin/reboot/reboot.8
@@ -29,6 +29,7 @@
 .\" $FreeBSD$
 .\"
 .Dd October 11, 2010
+.Dd Jan 06, 2016
 .Dt REBOOT 8
 .Os
 .Sh NAME
@@ -39,16 +40,16 @@
 .Nd stopping and restarting the system
 .Sh SYNOPSIS
 .Nm halt
-.Op Fl lnpq
+.Op Fl lNnpq
 .Op Fl k Ar kernel
 .Nm
-.Op Fl dlnpq
+.Op Fl dlNnpq
 .Op Fl k Ar kernel
 .Nm fasthalt
-.Op Fl lnpq
+.Op Fl lNnpq
 .Op Fl k Ar kernel
 .Nm fastboot
-.Op Fl dlnpq
+.Op Fl dlNnpq
 .Op Fl k Ar kernel
 .Sh DESCRIPTION
 The
@@ -94,6 +95,16 @@ that call
 or
 .Nm halt
 and log this themselves.
+.It Fl N
+The file system cache is not flushed during the initial process clean-up,
+however the kernel level
+.Xr reboot 2
+is still processed with a sync.
+This option can be useful for performing a
+.Dq best-effort
+reboot when devices might be unavailable.
+This can happen when devices have been disconnected, such as with
+.Xr iscsi 4 .
 .It Fl n
 The file system cache is not flushed.
 This option should probably not be used.
diff --git a/sbin/reboot/reboot.c b/sbin/reboot/reboot.c
index d927db03c..6d590ac1b 100644
--- a/sbin/reboot/reboot.c
+++ b/sbin/reboot/reboot.c
@@ -67,7 +67,7 @@ main(int argc, char *argv[])
 {
 	struct utmpx utx;
 	const struct passwd *pw;
-	int ch, howto, i, fd, lflag, nflag, qflag, sverrno;
+	int ch, howto, i, fd, lflag, nflag, qflag, sverrno, Nflag;
 	u_int pageins;
 	const char *user, *kernel = NULL;
 
@@ -76,8 +76,8 @@ main(int argc, char *argv[])
 		howto = RB_HALT;
 	} else
 		howto = 0;
-	lflag = nflag = qflag = 0;
-	while ((ch = getopt(argc, argv, "dk:lnpq")) != -1)
+	lflag = nflag = qflag = Nflag = 0;
+	while ((ch = getopt(argc, argv, "dk:lNnpq")) != -1)
 		switch(ch) {
 		case 'd':
 			howto |= RB_DUMP;
@@ -92,6 +92,10 @@ main(int argc, char *argv[])
 			nflag = 1;
 			howto |= RB_NOSYNC;
 			break;
+		case 'N':
+			nflag = 1;
+			Nflag = 1;
+			break;
 		case 'p':
 			howto |= RB_POWEROFF;
 			break;
@@ -107,6 +111,8 @@ main(int argc, char *argv[])
 
 	if ((howto & (RB_DUMP | RB_HALT)) == (RB_DUMP | RB_HALT))
 		errx(1, "cannot dump (-d) when halting; must reboot instead");
+	if (Nflag && (howto & RB_NOSYNC) != 0)
+		errx(1, "-N cannot be used with -n");
 	if (geteuid()) {
 		errno = EPERM;
 		err(1, NULL);
-- 
2.45.0