fix(overlayfs): split overlayfs mount in two steps (bsc#1219778)

This commit splits the creation of required overlayfs underlaying
directories and the actual overlayfs mount. This way it is still
possible to mount the overlayfs with the generated sysroot.mount that
dmsquash-live creates.

The overlayfs tree is created in a pre-mount hook so it is executed
before sysroot.mount is started. Otherwise sysroot.mount starts and
fails before mount hooks are executed.

Signed-off-by: David Cassany <dcassany@suse.com>
(cherry picked from commit bddffed)

modules.d/90overlayfs/module-setup.sh

@@ -15,4 +15,5 @@ installkernel() {
 
 install() {
     inst_hook mount 01 "$moddir/mount-overlayfs.sh"
+    inst_hook pre-mount 01 "$moddir/prepare-overlayfs.sh"
 }

modules.d/90overlayfs/mount-overlayfs.sh

@@ -3,24 +3,11 @@
 type getarg > /dev/null 2>&1 || . /lib/dracut-lib.sh
 
 getargbool 0 rd.live.overlay.overlayfs && overlayfs="yes"
-getargbool 0 rd.live.overlay.reset -d -y reset_overlay && reset_overlay="yes"
 getargbool 0 rd.live.overlay.readonly -d -y readonly_overlay && readonly_overlay="--readonly" || readonly_overlay=""
 
 ROOTFLAGS="$(getarg rootflags)"
 
 if [ -n "$overlayfs" ]; then
-    if ! [ -e /run/rootfsbase ]; then
-        mkdir -m 0755 -p /run/rootfsbase
-        mount --bind "$NEWROOT" /run/rootfsbase
-    fi
-
-    mkdir -m 0755 -p /run/overlayfs
-    mkdir -m 0755 -p /run/ovlwork
-    if [ -n "$reset_overlay" ] && [ -h /run/overlayfs ]; then
-        ovlfsdir=$(readlink /run/overlayfs)
-        info "Resetting the OverlayFS overlay directory."
-        rm -r -- "${ovlfsdir:?}"/* "${ovlfsdir:?}"/.* > /dev/null 2>&1
-    fi
     if [ -n "$readonly_overlay" ] && [ -h /run/overlayfs-r ]; then
         ovlfs=lowerdir=/run/overlayfs-r:/run/rootfsbase
     else

modules.d/90overlayfs/prepare-overlayfs.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+
+type getarg > /dev/null 2>&1 || . /lib/dracut-lib.sh
+
+getargbool 0 rd.live.overlay.overlayfs && overlayfs="yes"
+getargbool 0 rd.live.overlay.reset -d -y reset_overlay && reset_overlay="yes"
+
+if [ -n "$overlayfs" ]; then
+    if ! [ -e /run/rootfsbase ]; then
+        mkdir -m 0755 -p /run/rootfsbase
+        mount --bind "$NEWROOT" /run/rootfsbase
+    fi
+
+    mkdir -m 0755 -p /run/overlayfs
+    mkdir -m 0755 -p /run/ovlwork
+    if [ -n "$reset_overlay" ] && [ -h /run/overlayfs ]; then
+        ovlfsdir=$(readlink /run/overlayfs)
+        info "Resetting the OverlayFS overlay directory."
+        rm -r -- "${ovlfsdir:?}"/* "${ovlfsdir:?}"/.* > /dev/null 2>&1
+    fi
+fi