From 4409e1965d65b3cb0061cb098f32c9ba9aaff18b Mon Sep 17 00:00:00 2001
From: kn <kn@openbsd.org>
Date: Sat, 17 Jan 2026 21:20:44 +0000
Subject: [PATCH] Check absoloute free space rather than usage percentage

10% on big (single filesystem) disks can still be plenty enough;
on the flip side, e.g. 10% of 3G /usr is often still too tight.

So instead of ">= 90% used", use "< 1G free" to bail out early.

Input OK sthen
---
 usr.sbin/sysupgrade/sysupgrade.sh | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/usr.sbin/sysupgrade/sysupgrade.sh b/usr.sbin/sysupgrade/sysupgrade.sh
index e56866bad14..de1b2703b88 100644
--- a/usr.sbin/sysupgrade/sysupgrade.sh
+++ b/usr.sbin/sysupgrade/sysupgrade.sh
@@ -1,6 +1,6 @@
 #!/bin/ksh
 #
-# $OpenBSD: sysupgrade.sh,v 1.60 2025/11/12 11:22:48 deraadt Exp $
+# $OpenBSD: sysupgrade.sh,v 1.61 2026/01/17 21:20:44 kn Exp $
 #
 # Copyright (c) 1997-2015 Todd Miller, Theo de Raadt, Ken Westerback
 # Copyright (c) 2015 Robert Peichaer <rpe@openbsd.org>
@@ -118,9 +118,8 @@ $FORCE_VERSION && $SNAP &&
 $FORCE && ! $SNAP &&
 	err "incompatible options: -f without -s"
 
-USED_USR=$(df -P /usr | awk 'NR==2 {print substr($5, 1, length($5)-1)}')
-if (( ${USED_USR} >= 90 )) && ! $FORCE; then
-    err "/usr appears too small. See sysupgrade(8) manpage about PRUNING."
+if df -kP /usr | ! awk 'NR == 2 && $4 < 1*1024^2 { exit(1) }' && ! $FORCE; then
+	err "/usr appears too small. See sysupgrade(8) manpage about PRUNING."
 fi
 
 if $SNAP; then