do not umount root, remount it. do not mount ro if not specified

also mount /usr readonly if "ro" is specified on the command line
if /usr is a btrfs subvolume of root, use the same mount options

modules.d/95rootfs-block/mount-root.sh

@@ -15,7 +15,6 @@ filter_rootopts() {
     local v
     while [ $# -gt 0 ]; do
         case $1 in
-            rw|ro);;
             defaults);;
             *)
                 v="$v,${1}";;
@@ -82,7 +81,7 @@ mount_root() {
         # the root filesystem,
         # remount it with the proper options
         rootopts="defaults"
-        while read dev mp fs opts rest; do
+        while read dev mp fs opts dump fsck; do
             # skip comments
             [ "${dev%%#*}" != "$dev" ] && continue
 
@@ -90,6 +89,7 @@ mount_root() {
                 # sanity - determine/fix fstype
                 rootfs=$(det_fs "${root#block:}" "$fs")
                 rootopts=$opts
+                rootfsck=$fsck
                 break
             fi
         done < "$NEWROOT/etc/fstab"
@@ -99,28 +99,26 @@ mount_root() {
 
     # we want rootflags (rflags) to take precedence so prepend rootopts to
     # them; rflags is guaranteed to not be empty
-    rflags="${rootopts:+"${rootopts},"}${rflags}"
+    rflags="${rootopts:+${rootopts},}${rflags}"
 
     # backslashes are treated as escape character in fstab
     # esc_root=$(echo ${root#block:} | sed 's,\\,\\\\,g')
     # printf '%s %s %s %s 1 1 \n' "$esc_root" "$NEWROOT" "$rootfs" "$rflags" >/etc/fstab
 
     ran_fsck=0
-    if [ -z "$fastboot" -a "$READONLY" != "yes" ] && \
-            ! strstr "${rflags},${rootopts}" _netdev && \
+    if [ "$rootfsck" != "0" -a -z "$fastboot" -a "$READONLY" != "yes" ] && \
+            ! strstr "${rflags}" _netdev && \
             ! getargbool 0 rd.skipfsck; then
-        umount "$NEWROOT"
         fsck_single "${root#block:}" "$rootfs" "$rflags" "$fsckoptions"
         _ret=$?
         [ $_ret -ne 255 ] && echo $_ret >/run/initramfs/root-fsck
         ran_fsck=1
     fi
 
-    if [ -n "$rootopts" -o "$ran_fsck" = "1" ]; then
-        info "Remounting ${root#block:} with -o ${rflags}"
-        umount "$NEWROOT" &>/dev/null
-        mount -t "$rootfs" -o "$rflags" "${root#block:}" "$NEWROOT" 2>&1 | vinfo
-    fi
+    echo "${root#block:} $NEWROOT $rootfs ${rflags:-defaults} 0 $rootfsck" >> /etc/fstab
+
+    info "Remounting ${root#block:} with -o ${rflags}"
+    mount -o remount "$NEWROOT" 2>&1 | vinfo
 
     [ -f "$NEWROOT"/forcefsck ] && rm -f "$NEWROOT"/forcefsck 2>/dev/null
     [ -f "$NEWROOT"/.autofsck ] && rm -f "$NEWROOT"/.autofsck 2>/dev/null

modules.d/98usrmount/mount-usr.sh

@@ -52,6 +52,15 @@ mount_usr()
                     _dev="/dev/disk/by-uuid/${_dev#UUID=}"
                     ;;
             esac
+            if strstr "$_opts" "subvol=" && \
+                [ "${root#block:}" -ef $_dev ]
+                [ -n "$rflags" ]; then
+                # for btrfs subvolumes we have to mount /usr with the same rflags
+                _opts="${_opts:+${_opts},}${rflags}"
+            elif getarg ro; then
+                # if "ro" is specified, we want /usr to be readonly, too
+                _opts="${_opts:+${_opts},}ro"
+            fi
             echo "$_dev ${NEWROOT}${_mp} $_fs ${_opts} $_freq $_passno"
             _usr_found="1"
             break

modules.d/99base/parse-root-opts.sh

@@ -5,9 +5,11 @@
 root=$(getarg root=)
 
 if rflags="$(getarg rootflags=)"; then
-    getarg rw && rflags="${rflags},rw" || rflags="${rflags},ro"
+    getarg rw && rflags="${rflags},rw"
+    getarg ro && rflags="${rflags},ro"
 else
-    getarg rw && rflags=rw || rflags=ro
+    getarg rw && rflags=rw
+    getarg ro && rflags=ro
 fi
 
 fstype="$(getarg rootfstype=)"