umount: add man page note that --force is not perfect

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/umount.8 b/sys-utils/umount.8
index 8236ecddb057ec25ac21f75efced21e20ffced4c..2155f2ba52ada1366ac8fe29f4a1ae09b5c34da1 100644 (file)
--- a/sys-utils/umount.8
+++ b/sys-utils/umount.8
@@ -94,6 +94,10 @@ option.
 .BR \-f , " \-\-force"
 Force an unmount (in case of an unreachable NFS system).  (Requires kernel
 2.1.116 or later.)
+
+Note that this option does not guarantee that umount command does not hang.
+It's strongly recommended to use absolute paths without symlinks to avoid
+unwanted readlink and stat syscalls on unreachable NFS in umount.
 .TP
 .BR \-i , " \-\-internal\-only"
 Do not call the \fB/sbin/umount.\fIfilesystem\fR helper even if it exists.