[KERNEL] [15/04/10][5.1/3G+WIFI][Fix for empty directories after mount] [V18]

vorcers · Jan 19, 2013

Hey Guys,

mkasick released in his thread a fix for the mounting problems in Android >= 4.2.

Description of the issue:

mkasick said:
Android >= 4.2 breaks Dalvik-apps that mount file systems to be shared with other apps. This includes CifsManager, Mount Manager, essentially anything that mounts cifs shares, FUSE file sytems, etc. The symptom is that the mounted contents appear fine to app that peforms the mount operation (assuming the app itself provides the ability to browse the contents), but every other app only sees an empty directory at the mount point.

As I said - mkasick released a solution - so I compiled my own kernel. Now we can again easy mount cifs and others! All old apps should work. Only limitation: the mount point needs to be outside of /storage (and also /mnt/sdcard/). Fix for this: Mount within /data/media/0 -- android will redirect the mount so you can access the mounted-files from this folders.

The kernel is a "stock kernel" and also includes:

mkasick Patch
Built-In cifs, md4, utf8, nfs, f2fs (Since V17)
kexec hardboot patch (The full patch, allows boot as host and as guest)
As Modules: .ko: snd-usb-audio and all of its devices (Installed, but not modprobe'd since V17)
[Since V16/Android 5.0.2] Fix for baseband_xmm_power wakelock on tilapia (see Hints and Bugs since V16 / Android 5.0 / Lollipop ; for Android 4.4.4 see this post)

mkasick recommends in his thread to patch dalavik, but for the stock-roms it is easier to patch the kernel.

Known Bugs:

Since Android 5.0.X/V16: SELinux is now blocking the access of cifs/nfs even in read. Also nfs isn't loaded at boot time anymore. For more information look below.
Since Android 4.4.X: There is a known bug with mounting cifs (you can't write). The solution is (try at your own risk) here. If you want to do this workaround at boot-time, you can flash the zip linked here.
With SuperSU >= 1.50 && < 1.65 the mounted folders are empty. Please update! (For more Info see hide-box "SuperSU Information" below)

Hints and Bugs since V16 / Android 5.0 / Lollipop:

Downloads

(Kernels since v8 are only tested by me for the 3G version (tilapia) - but should also work with wifi (grouper).)

The flash of the kernel shouldn't break anything, but I recommend to backup your system.

Download-Links for grouper and tilapia:

Android 5.1: Kernel: Grouper: boot-grouper-vorcers-gf5d7b8b-v18.zip ; Tilapia: boot-tilapia-vorcers-gf5d7b8b-v18.zip
Android 5.0.2: Kernel: Grouper: boot-grouper-vorcers-g6ff7a51-v16.zip ; Tilapia: boot-tilapia-vorcers-g6ff7a51-v16.zip
Android 4.4.4: Kernel: Grouper: boot-grouper-vorcers-g1e42d16-v13.zip ; Tilapia: boot-tilapia-vorcers-g1e42d16-v13.zip

In V11 the kernel modules are placed in /data instead of /system. If you are upgrade from < V11 and you want to delete the modules in /system, you can delete the folder "/system/vorcers_kernelmodules" manually, or you use this CWM-Zip to delete.

Download-Links only for grouper: (try on tilapia at your own risk)

Android 4.3: Kernel: boot-grouper-vorcers-g1e8b3d8-v7.zip Kernelmodules: integrated
Android 4.2.2: Kernel: boot-grouper-vorcers-g05b777c-v4.zip Kernelmodules: kernelmodules-vorcers-g05b777c-v2.zip

Extra-Links:

My Repository for this Kernel (also contains old versions): https://www.mediafire.com/folder/j9iocde4l20c7/Kernel
Stock-Kernels: https://www.mediafire.com/folder/d3mj3k3v61jzu/Stock Kernels
A zip which contains the Patches and modifications I made: https://www.mediafire.com/folder/kvdmcsl16x0ox/Sources

Integration wishes for new kernelmodules to support new hardware are always welcome (you will get .ko's for my kernel)

Have a lot of fun!

Sources:
http://xdaforums.com/showthread.php?t=2106480 (Mount fix)
http://xdaforums.com/showthread.php?t=2104706 (Hardboot patch)
http://source.android.com/source/building-kernels.html
http://android-dls.com/wiki/index.php?title=HOWTO:_Unpack,_Edit,_and_Re-Pack_Boot_Images
http://nek0s.blogspot.de/2012/12/nexus-7-ramdisk.html

Changelog:

SuperSU Information:

Some gimmick: One"click"mount-Shell-Script

Thanks to:
mkasick - for the patch
farhanito - for the basic code in the .zip
glimmling - for the tasker apk's running the One"click"mount-Shell-Script
jfmcbrayer / Sgt. Meow - for the baseband_xmm_power wakelock workaround

glimmling · Jan 19, 2013

Hi and thanks for this!

I'm a Linux noob and have some questions.
If I understand it correctly, I don't need Stickmount anymore with your kernel. Do I need to mount an usb stick in the terminal or is there a way to automate this with tasker for example?
What is the correct mount command syntax?

The old way to mount a network share with cifs manager in 4.1.2 I used this guide with external modules:
http://xdaforums.com/showpost.php?p=29055478&postcount=10

Can you please show an example configuration for Cifs Manager, when I use your kernel?

Many thanks!

vorcers · Jan 19, 2013

You still can use stickmount. You will see no difference, because stickmount uses the old "debuggerd" method. (Well, I did not test stickmount with the new fix, but it should work...)

For cifs:
I already included cifs in my kernel. You don't need to load them anymore. You can now easy use cifs manager, if you are mounting under /mounts (with the v2 of my kernel)

Here an screenshot of an configuration I use with CifsManager:

It is only important, to use a path in /mounts/. As I tested, CifsManager automatically creates the mount-point inside /mounts/.

It is possible, that applications which doesn't support browsing in file system, can't access /mounts. But some provide an option to the start directory or something like that (OfficeSuite for example) the directory just need to be set to /mounts. This is the reason, why stickmount uses an mountpoint inside /mnt/sdcard ... I am using OI Filemanager. It is a quite nice application. It also supports starting apps with the selected file.

I hope, I could help you.

glimmling · Jan 19, 2013

AW: [KERNEL][WIFI][4.2.X] Included "Fix for empty app-mounted directories"

Thank you.
Cifs is working for me now, but I want to get rid of stickmount.
Since android 4.2.x I always get empty folders with stickmount, even with the latest version. I want to replace it with a new method. But I don't know the mount command and the device name to mount a standard usb-stick.

mount [devicename?] /mounts/usb ???

EDIT: I replaced stickmount with usb otg helper http://xdaforums.com/showthread.php?t=1588940. Now I can see the files of a mounted usb-stick in every app, no more empty folders.

Gesendet von meinem Nexus 7 mit Tapatalk 2

vorcers · Jan 19, 2013

Ah. I forgot USB-OTG helper. Well, with this app, the mounting of devices already worked without the fix. It also uses the "debuggerd" workaround like stickmount. You will need the kernel-fix only for mounting cifs.

I stay at my new oneclickmount-shellscript, because I want to know what the applications do ^^ I don't trust stickmount and usb-otg-helper...

glimmling · Jan 19, 2013

AW: [KERNEL][WIFI][4.2.X] Included "Fix for empty app-mounted directories"

Can you please share your script?

Gesendet von meinem Nexus 7 mit Tapatalk 2

vorcers · Jan 19, 2013

Look in the first post, I attached it there

farhanito · Jan 20, 2013

Re: [KERNEL][WIFI][4.2.X] Included "Fix for empty app-mounted directories"

Thanks vorcers,

Here is flashable zip of v2
http://www.mediafire.com/download.php?gnn4n5p8plhdkv8
Md5= 0394f49ae911ec7a2d7cf845c5916fb6

Hope you can figure out the /storage problem
Every other kernel should implement this fix

Sent from my Nexus 7 using Tapatalk 2

Doncabezon · Jan 20, 2013

This is a great! Question, since the mount point needs to be outside of /storage and /mnt/sdcard does that mean I can not use this to mount app data? ex. gameloft, etc (using Directory Bind)

bubbleguuum · Jan 20, 2013

It would be really awesome if a fix or hack to this issue (empty directories if app is not launched before mounting) could be found without requiring a kernel patch.

I tried the debuggerd method supposedly used by StickMount and found that it didn't work: app still sees empty mount if its process is started after mount.

Btw, app sees mounts if its process is started before because mounts are propagated in that case. They are just not inherited on process creation due to how zygote spawn app processes and initializes their mounts.

I never understood how hacking debuggerd could work to fix this issue as this is not much different to me than running a shell script invoking adb shell in loopback mode (requires root), since debuggerd and adbd run with identical priviledges:

Code:

setprop service.adb.tcp.port 5555
stop adbd
start adbd
adb connect localhost
adb shell mount ....

I've found a workaround that involves hijaking the obb directory by mounting whatever you want over /mnt/shell/emulated/obb. This directory is systematically bind mounted by the Zygote process in <external storage root>/Android/obb (see source code) when it spawns an app's process

Unfortunately this hack is not very usable because it has the side effect that any app expecting its data in the obb directory will not find it. And you can only mount one filesystem here.

Conclusion: with the new 4.2 multiuser support, Google made miserable all apps dealing with mounting.

YayYouFixedIt · Jan 20, 2013

Re: [KERNEL][WIFI][4.2.X] Included "Fix for empty app-mounted directories"

I havent tried this kernel yet, but it might appear by simply set the mount point to /data/media/0/MOUNTNAME
Might appear in storage that way.
worked for me using sshfsandroid mounting the pc harddrive over the wifi.
EDIT: I just flashed this kernel and its working the way I said. THANKS A BUNCH.:thumbup:
Sent from my Transformer TF101 using Tapatalk HD

vorcers · Jan 20, 2013

Half-OT: Did someone tested with the new fix the superuser-function in non-primary accounts?

----------------------------------

farhanito said:
Thanks vorcers,

Here is flashable zip of v2
http://www.mediafire.com/download.php?gnn4n5p8plhdkv8
Md5= 0394f49ae911ec7a2d7cf845c5916fb6

Hope you can figure out the /storage problem
Every other kernel should implement this fix

Sent from my Nexus 7 using Tapatalk 2

Very nice, If you don't object, I would use your zip in the future as base and would only offer .zip's.

Doncabezon said:
This is a great! Question, since the mount point needs to be outside of /storage and /mnt/sdcard does that mean I can not use this to mount app data? ex. gameloft, etc (using Directory Bind)

As mkasick said in his patch, also fixing the /storage/ folder, can cause other problems:

mkasick in his patch said:
Unfortunately bind mounts from outside /storage may retain the recursive-shared property (bug?). This means any additional namespace-specific bind mounts (e.g., /storage/emulated/0/Android/obb) will also appear, shared in all namespaces, at their respective source paths (e.g., /mnt/shell/emulated/0/Android/obb), possibly leading to hundreds of /proc/mounts-visible bind mounts. As a workaround, mark /mnt/shell/emulated also as recursive-slave so that subsequent bind mounts are confined to their namespaces.

To "fix" the /storage problem, only 6 lines of the patch need to be removed. But it also can break the multiuser-feature. I will test it in the next days.

bubbleguuum said:
It would be really awesome if a fix or hack to this issue (empty directories if app is not launched before mounting) could be found without requiring a kernel patch.

As an alternative (which is not really an alternative...) is to use the dalavik patch. But I think the Kernel-Patch is easy for stock.
Anyway, I think there will never be a 100% solution without patching. Only Google can solve this problem, by changing their multiuser architecture... (Or they mark by stock the root folder as non-slave, but that wouldn't fix the /storage problem...)

Doncabezon · Jan 21, 2013

Re: [KERNEL][WIFI][4.2.X] Included "Fix for empty app-mounted directories"

What if I don't need multiuser support. Don't care much if it becomes broke, since my son has a kindle and my wife dare not touch my tablet save for playing Temple Run Brave

Sent from my Nexus 7 using xda premium

farhanito · Jan 21, 2013

Re: [KERNEL][WIFI][4.2.X] Included "Fix for empty app-mounted directories"

vorcers said:
----------------------------------

Very nice, If you don't object, I would use your zip in the future as base and would only offer .zip's.

Of course, no problem

Sent from my Nexus 7 using Tapatalk 2

forceu · Jan 21, 2013

Thank you so much for that kernel! That is exactly what I have been looking for!

vorcers · Jan 21, 2013

I added .zip's and released a new oneclickmount.sh version. :highfive:

Doncabezon · Jan 23, 2013

Re: [KERNEL][WIFI][4.2.X] Included "Fix for empty app-mounted directories"

YayYouFixedIt said:
I havent tried this kernel yet, but it might appear by simply set the mount point to /data/media/0/MOUNTNAME
Might appear in storage that way.
worked for me using sshfsandroid mounting the pc harddrive over the wifi.
EDIT: I just flashed this kernel and its working the way I said. THANKS A BUNCH.:thumbup:
Sent from my Transformer TF101 using Tapatalk HD

So using this method, directory bind works?

Sent from my Nexus 7 using xda premium

YayYouFixedIt · Jan 23, 2013

Re: [KERNEL][WIFI][4.2.X] Included "Fix for empty app-mounted directories"

Actually it did seem too. No idea why. Both on the n7 and tf101 for sshfsandroid only.
But eventully I just made it mount to /Removable/pcharddrivefoldermountpointnamelong examplee

and that was OK for me too. Ssomone mentioned it can be mounted anywhere outside storageed
EDIT: only using this kernel and I am using dirty aokp2.8 ATM.
I just checked again and the bind works as /data/media/0/PC which wouldnbe good if you want to download directly from dolphin into the PC.

ThurstonX · Jan 25, 2013

vorcers said:
I added .zip's and released a new oneclickmount.sh version. :highfive:

Just wanted to give a HUGE THANKS for compiling your kernel and making it available, to farhanito for the flashable zip, and of course to mkasick for the concept

CIFS Manager works like a charm, and DeaDBeeF Player can see my shares, so me=HAPPY!

Nice to be on 4.2.1 now.
Y'all rule :highfive:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I'll just add that Mount Manager also works like a charm, automounting under /mounts whatever shares you define.

vorcers · Jan 30, 2013

I created a new oneclickmount version, with some bug-fixes.

http://xdaforums.com/attachment.php?attachmentid=1690089&d=1359582536

They appeared if you use more then one device at the nexus parallel. It simply only mounted one device.

I also set the standard-mountpoint to /data/media/0/mounts. With that, we can use our files also in /mnt/sdcard. :highfive: (Android re-directs it...)

This also works for bind's. I could bind /mounts/ to /data/media/0/mounts . It also works... Maybe someone helps that for using some games.

[KERNEL] [15/04/10][5.1/3G+WIFI][Fix for empty directories after mount] [V18]

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