Android N and system write

[ja_som]

Hi,
I know that is too soon to want something from Total Commander on Android N. But I only want to say, that system remount does not work, so is not possible to write to system, read works. My Nexus 5X is rooted with SuperSU 2.70, and when I try to remount system I get this error:
http://imgur.com/QpDfMD5

[ghisler(Author)]

The error isn't specific to N. It means that there are open files on that volume which prevent the mount command from re-mounting the volume.

[ja_som]

Thanks for your reply.

Here is log from CatLog app, maybe it will be more helpful

https://drive.google.com/file/d/0B0bWVvdcNSQlS0VUNjFjTmV3dmc/view?usp=sharing

[ghisler(Author)]

Well, it doesn't tell me anything new:

03-17 13:44:19.621 D/LightFlow:MainRunningService(nowJustAccessibility)( 3779): mount: '/dev/block/platform/soc.0/f9824900.sdhci/by-name/system'->'/system': Device or resource busy]

It also tells me that the partition has open files and cannot be remounted for that reason.

[ja_som]

OK, thanks again. Will see if something will change in next (maybe in final) release of N.

[ghisler(Author)]

Maybe it helps to reboot the system.

[ja_som]

I tried it now, is same as before.

[ghisler(Author)]

1. Could you try it with a button?
Command: su
Parameters: mount -o remount,rw /system
2. Could you try other apps with root support?

[ja_som]

1. If this
Image: http://i.imgur.com/kdVzPOU.jpg
is right, then it does not work
Image: http://i.imgur.com/OhDgxxq.jpg

2. I found only one file manager which works with write function to system, Root Browser
https://play.google.com/store/apps/details?id=com.jrummy.root.browserfree
Also I use Titanium Backup, f.lux, AdAway, Terminal Emulator, Flashify, FlashFire and Wakelock Detector with root rights.

[ghisler(Author)]

I have downloaded and decompiled Root Browser. It uses mount too, but seems to call it with different parameters:
mount -o remount,rw /devicename /system

You need to check in the /proc/mounts file which device is mounted as /system, and then put this in "devicename".

[ja_som]

OK
in mounts I found this:

Code: Select all

/dev/block/platform/soc.0/f9824900.sdhci/by-name/system /system ext4 ro,seclabel,noatime,data=ordered 0 0

So I use

Code: Select all

mount -o remount,rw /dev/block/platform/soc.0/f9824900.sdhci/by-name/system /system

which ends with same result as before:
Image: http://i.imgur.com/OhDgxxq.jpg


Here is full mounts file:
http://pastebin.com/5upwarbv

[ghisler(Author)]

Sorry, I really don't understand how Root Browser can remount a busy file system. I don't know enough of Linux to handle that. Therefore please use Root Browser instead of Total Commander for this operation, I cannot help you.

[ja_som]

It's OK, thank you anyway.

[ja_som]

Hello again
I talked with Chainfire (author of SuperSU) and he pointed me here:
https://plus.google.com/+Chainfire/posts/dGPQytapwe3

and I tried command

Code: Select all

mount -o rw,remount /system

which works (also on Marshmallow)

Is it possible to use this command as default in your app (so I don't need to use custom button)?

[ghisler(Author)]

That's odd, the order of the paramters (remount and rw) should not matter at all. Why would this give a "busy" error on Marshmallow? It makes no sense at all.

Is it possible to use this command as default in your app (so I don't need to use custom button)?

I will try it in beta 2. If you are on the beta channel, you should receive the beta automatically when it gets available.