Magical Overlayfs v3.2.2 Fix Unofficial

Magical Overlayfs v3.2.2 Fix Unofficial

Description:

Use OverlayFS to make |A| read-only system partitions become |B| read-write partitions. OverlayFS MUST |C| be supported by kernel! |D| Recommended for EROFS ROMs.

Changelog:

The |E| release from the upstream |F| repo of v3.2.2 is |G| broken somehow with Magisk |H| v27.0. I simply rebuilt |J| it per comments in |K| open issues on that |L| repo and now it |M| works.

  • agreenbhm

Notes: works on systems |O| BELOW a13 is not |P| guaranteed!

Version: v3.2.2-Fixed

Author: agreenbhm, HuskyDG |Q| (repo – base)

Get Link |R|    

Magisk-overlayfs-release_v3.2.2-fixed |S|    

Magisk Overlayfs

On Android |U| 10+, system partitions might |V| no longer be able |Y| to remount as read-write. |Z| For devices use dynamic |A| partition, it is nearly |B| impossible to modify system |C| partiton as there is |D| no space left. This |E| module solves these problem |F| by using OverlayFS. So |G| what is OverlayFS? On |H| Wikipedia:

OverlayFS is |J| a union mount filesystem |K| implementation for Linux. It |L| combines multiple different underlying |M| mount points into one, |O| resulting in single directory |P| structure that contains underlying |Q| files and sub-directories from |R| all sources. Common applications |S| overlay a read/write partition |U| over a read-only partition, |V| such as with LiveCDs |Y| and IoT devices with |Z| limited flash memory write |A| cycles.

Benefits of using overlayfs |B| for system partitions:

  • Make most |C| parts of system partition |D| (/system, /vendor, /product, /system_ext, |E| /odm, /odm_dlkm, /vendor_dlkm, …) |F| become read-write.
  • /data storage is |G| used for upperdir of |H| OverlayFS mount. However, on |J| some kernel, f2fs is |K| not supported by OverlayFS |L| and cannot be used |M| directly. The workaround is |O| to create an ext4 |P| loop image then mount |Q| it.
  • All modifications to overlayfs |R| partition will not be |S| made directly, but will |U| be stored in upperdir, |V| so it is easy |Y| to revert. Just need |Z| to remove/disable module so |A| your system will return |B| to untouched stage.
  • Support Magisk |C| version 23.0+ and latest |D| version of KernelSU

If you |E| are interested in OverlayFS, |F| you can read documentation |G| at https://docs.kernel.org/filesystems/overlayfs.html


Build

There |H| is two way:

GitHub Actions

  • Fork |J| this repo and run |K| github actions

Linux/WSL

  1. Clone this repo |L| to your device
git clone |M|  
 
 
 
 http://github.com/HuskyDG/Magisk_OverlayFS && cd Magisk_OverlayFS
    |O| start="2">
  1. Setup Android NDK in |P| repository directory
wget https://dl.google.com/android/repository/android-ndk-r23b-linux.zip unzip |Q|  
 
 
 
 android-ndk-r23b-linux.zip
  1. Run bash build.sh

KernelSU |R| problem

  • The KernelSU module is |S| similar to Magisk in |U| that it allows users |V| to modify the system |Y| partition while maintaining system |Z| integrity. It does this |A| through the implementation of |B| overlayfs. However, it’s important |C| to note that KernelSU |D| makes changes to the |E| system partition by using |F| read-only overlayfs, which also |G| mounts on top of |H| magic_overlayfs and prevent system |J| from being remounted as |K| read-write. If you want |L| to remount your system |M| partitions as read-write, you |O| simply need to first |P| unmount the KernelSU overlayfs |Q| using this command:
nsenter -t |R|  
 
 
 
 1 -m sh overlayfs_system |S|  
 
 
 
 --unmount-ksu

or set DO_UNMOUNT_KSU=true in |U| /data/adb/modules(_update)/magisk_overlayfs/mode.sh

  • After that you will |V| be able to remount |Y| system as read-write

Change OverlayFS |Z| mode

  • OverlayFS is mounted as |A| read-only by default
  • Configure overlayfs |B| mode in /data/adb/modules(_update)/magisk_overlayfs/mode.sh to |C| change mode of OverlayFS

Read-write |D| mode of overlayfs will |E| cause baseband on some |F| devices stop working

# 0 |G|  
 
 
 
 - read-only but can |H|  
 
 
 
 still remount as read-write |J|  
 
 
 
 # 1 - read-write |K|  
 
 
 
 default # 2 - |L|  
 
 
 
 read-only locked (cannot remount |M|  
 
 
 
 as read-write) 
export OVERLAY_MODE=2
  • OverlayFS |O| upper loop device will |P| be setup at /dev/block/overlayfs_loop
  • On |Q| Magisk, OverlayFS upper loop |R| are mounted at $(magisk |S| --path)/overlayfs_mnt. You can make |U| modifications through this path |V| to make changes to |Y| overlayfs mounted in system.

Modify |Z| system files with OverlayFS

  • If |A| you are lazy to |B| remount, please modify mode.sh |C| and set it to |D| OVERLAY_MODE=1 so overlayfs will |E| be always read-write every |F| boot.
  • You can quickly remount |G| all overlayfs to read-write |H| by this command in |J| terminal:
su -mm -c magic_remount_rw
  • After |K| that you can restore |L| all system partitons back |M| to read-only mode by |O| this commamd in terminal:
su |P|  
 
 
 
 -mm -c magic_remount_ro


Overlayfs-based Magisk |Q| module

  • If you want to |R| use overlayfs mount for |S| your module, add these |U| line to the end |V| of customize.sh:
OVERLAY_IMAGE_EXTRA=0   |Y|  
 
 
 
   # number |Z|  
 
 
 
 of kb need to |A|  
 
 
 
 be added to overlay.img |B|  
 
 
 
 OVERLAY_IMAGE_SHRINK=true # shrink overlay.img |C|  
 
 
 
 or not? 
# Only |D|  
 
 
 
 use OverlayFS if Magisk_OverlayFS |E|  
 
 
 
 is installed if [ |F|  
 
 
 
 -f "/data/adb/modules/magisk_overlayfs/util_functions.sh" ] && |G|  
 
 
 
     |H|  
 
 
 
 /data/adb/modules/magisk_overlayfs/overlayfs_system --test; then  |J|  
 
 
 
 ui_print "- Add support |K|  
 
 
 
 for overlayfs"  . |L|  
 
 
 
 /data/adb/modules/magisk_overlayfs/util_functions.sh  support_overlayfs && |M|  
 
 
 
 rm -rf "$MODPATH"/system fi

Bugreport

  • Magisk/KernelSU |O| version
  • Magisk/KernelSU logs
  • /cache/overlayfs.log
  • logcat, dmesg, …

Reset |P| overlayfs

  • Remove /data/adb/overlay and reinstall |Q| module

Without Magisk

  • Simple configuration to |R| test:
# - Create a |S|  
 
 
 
 writeable directory in ext4 |U|  
 
 
 
 (f2fs) /data # which |V|  
 
 
 
 will be used for |Y|  
 
 
 
 upperdir # - On |Z|  
 
 
 
 some Kernel, f2fs is |A|  
 
 
 
 not supported by OverlayFS |B|  
 
 
 
 # and cannot be |C|  
 
 
 
 used directly WRITEABLE=/data/overlayfs 
mkdir |D|  
 
 
 
 -p "$WRITEABLE" 
# - |E|  
 
 
 
 Export list of modules |F|  
 
 
 
 if you want to |G|  
 
 
 
 load mounts by overlayfs |H|  
 
 
 
 # - If you |J|  
 
 
 
 have /vendor /product /system_ext |K|  
 
 
 
 as seperate partitons # |L|  
 
 
 
 - Please move it |M|  
 
 
 
 out of "system" folder, |O|  
 
 
 
 overwise **BOOM** export OVERLAYLIST=/data/adb/modules/module_a:/data/adb/modules/module_b |P|  
 
 
 
 
# - If there |Q|  
 
 
 
 is Magisk, export this |R|  
 
 
 
 in post-fs-data.sh (before magic |S|  
 
 
 
 mount): export MAGISKTMP="$(magisk --path)" |U|  
 
 
 
 
# - Load overlayfs |V|  
 
 
 
 ./overlayfs_system "$WRITEABLE"
|Y|


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