From 75471fe3b7d5ea78fe465fdfe3eb64ae4ee363c8 Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Sun, 11 Sep 2016 16:41:12 +0200
Subject: scripts/restore-etc: do not mount a tmpfs on /etc if / is a ramfs

When booting an initramfs, it's pointless to mount some tmpfs everywhere
since we can already extract /etc into the / FS. We now detect that / is
a ramfs and avoid mounting the tmpfs in this case. At unmount time, we
remove the whole /etc entries if we're on a ramfs.

Note that we use stat to detect the filesystem type on /, and the script
ensures the tmpfs is still used if the "stat" binary is not present.
---
 scripts/restore-etc | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/scripts/restore-etc b/scripts/restore-etc
index 2e55690..1d00fca 100755
--- a/scripts/restore-etc
+++ b/scripts/restore-etc
@@ -125,16 +125,22 @@ list_changes() {
   fi
 }
 
-# tries to unmount /etc
+# tries to unmount /etc and to delete everything there if / is a ramfs
 unmount_etc() {
   while umount "$ROOTDIR/etc" >/dev/null 2>&1; do : ; done
+  if [ "$(stat -fc "%T" "$ROOTDIR/" 2>/dev/null)" = "ramfs" ]; then
+    rm -rf "$ROOTDIR/etc/." >/dev/null 2>&1
+  fi
 }
 
-# mount /etc unless config.rc already exists
+# mount /etc unless config.rc already exists or / is a ramfs
 mount_etc() {
   if [ ! -e "$ROOTDIR/etc/config.rc" ]; then
-    mount -n -t $FSTYPE ${MOUNTOPT:+-o $MOUNTOPT} "$ROOTDIR/etc" "$ROOTDIR/etc" || \
-      mount -n -t $FSTYPE "$ROOTDIR/etc" "$ROOTDIR/etc"
+    mkdir -p "$ROOTDIR/etc" >/dev/null 2>&1
+    if [ "$(stat -fc "%T" "$ROOTDIR/" 2>/dev/null)" != "ramfs" ]; then
+      mount -n -t $FSTYPE ${MOUNTOPT:+-o $MOUNTOPT} "$ROOTDIR/etc" "$ROOTDIR/etc" || \
+        mount -n -t $FSTYPE "$ROOTDIR/etc" "$ROOTDIR/etc"
+    fi
   fi
 }
 
-- 
1.7.12.1