firstboot: add support for union mounts

SVN-Revision: 17778

diff --git a/package/base-files/files/sbin/firstboot b/package/base-files/files/sbin/firstboot
index 8453b300966902a2832e23eb8d396c5a0776bd53..d5a0981f43011c34d766fd97254cdd23ba58fb76 100755 (executable)
--- a/package/base-files/files/sbin/firstboot
+++ b/package/base-files/files/sbin/firstboot
@@ -48,7 +48,12 @@ pivot() { # <new_root> <old_root>
 fopivot() { # <rw_root> <ro_root> <dupe?>
        root=$1
        {
-               mount -t mini_fo -o base=/,sto=$1 "mini_fo:$1" /mnt 2>&- && root=/mnt
+               if grep -q mini_fo /proc/filesystems; then
+                       mount -t mini_fo -o base=/,sto=$1 "mini_fo:$1" /mnt 2>&- && root=/mnt
+               else
+                       mount --bind / /mnt
+                       mount --bind -o union "$1" /mnt && root=/mnt 
+               fi
        } || {
                [ "$3" = "1" ] && {
                mount | grep "on $1 type" 2>&- 1>&- || mount -o bind $1 $1
@@ -60,6 +65,7 @@ fopivot() { # <rw_root> <ro_root> <dupe?>
 
 ramoverlay() {
        mkdir -p /tmp/root
+       mount -t tmpfs root /tmp/root
        fopivot /tmp/root /rom 1
 }
 
@@ -78,28 +84,59 @@ ramoverlay() {
        }
 
        [ "$1" = "switch2jffs" ] && {
-               mount "$mtdpart" /rom/jffs -t jffs2 || exit
-
-               # try to avoid fs changing while copying
-               mount -o remount,ro none / 2>&-
-
-               # copy ramoverlay to jffs2
-               echo -n "copying files ... "
-               cp -a /tmp/root/* /rom/jffs 2>&-
-               echo "done"
-
-               # switch back to squashfs (temporarily)
-               # and park the ramdisk ontop of /tmp/root
-               pivot /rom /mnt
-               mount -o move /mnt /tmp/root
-
-               # /jffs is the overlay
-               # /rom is the readonly
-               fopivot /jffs /rom
-
-               # try to get rid of /tmp/root
-               # this will almost always fail
-               umount /tmp/root 2>&-
+               if grep -q mini_fo /proc/filesystems; then
+                       mount "$mtdpart" /rom/jffs -t jffs2 || exit
+
+                       # try to avoid fs changing while copying
+                       mount -o remount,ro none / 2>&-
+
+                       # copy ramoverlay to jffs2
+                       echo -n "copying files ... "
+                       cp -a /tmp/root/* /rom/jffs 2>&-
+                       echo "done"
+
+                       # switch back to squashfs (temporarily)
+                       # and park the ramdisk ontop of /tmp/root
+                       pivot /rom /mnt
+                       mount -o move /mnt /tmp/root
+
+                       # /jffs is the overlay
+                       # /rom is the readonly
+                       fopivot /jffs /rom
+
+                       # try to get rid of /tmp/root
+                       # this will almost always fail
+                       umount /tmp/root 2>&-
+               else
+                       # switch back to squashfs temporarily
+                       pivot /rom /mnt
+
+                       # get rid of the old overlay
+                       umount -l /mnt
+
+                       # another umount to get rid of the bind from /tmp/root
+                       umount -l /mnt
+
+                       # initialize jffs2
+                       mount "$mtdpart" /jffs -t jffs2 || exit
+
+                       # workaround to ensure that union can attach properly
+                       sync
+                       ls /jffs >/dev/null
+
+                       # switch to the new (empty) jffs2
+                       fopivot /jffs /rom 1
+
+                       # copy ramoverlay to jffs2, must be done after switching
+                       # to the new rootfs to avoid creating opaque directories
+                       echo -n "copying files ... "
+                       cp -a /tmp/root/* / >/dev/null 2>&1
+                       sync
+                       echo "done"
+
+                       umount -l /jffs
+                       umount -l /tmp/root
+               fi
 
                exit 0
        }