[Android Q&A, Help & Troubleshooting] Nikooo777:
hey everyone.

So, I am desperately trying to force/trick google camera to write to the sd card rather than to the internal card.

my sdcard is formatted as ext4 and in its root i created the directory: DCIM_sd.

now, using ssh (as root ofc) i navigated to: /data/media/0, deleted DCIM and re-created it. gave right ownership and permissions.

At this point I executed this command:

busybox mount --bind /storage/sdcard1/DCIM_sd/ DCIM

and followed by df -h just to confirm that it was successful:

localhost 0 # df -h
Filesystem Size Used Available Use% Mounted on
tmpfs 415.8M 108.0K 415.7M 0% /dev
none 415.8M 12.0K 415.8M 0% /sys/fs/cgroup
tmpfs 415.8M 0 415.8M 0% /mnt/asec
tmpfs 415.8M 0 415.8M 0% /mnt/obb
/dev/block/mmcblk0p3 19.7M 11.3M 8.3M 58% /efs
/dev/block/mmcblk0p9 1.5G 524.3M 987.6M 35% /system
/dev/block/mmcblk0p8 1007.9M 18.8M 989.1M 2% /cache
/dev/block/mmcblk0p10
551.2M 9.2M 542.0M 2% /preload
/dev/block/mmcblk0p12
11.3G 4.1G 7.3G 36% /data
/dev/fuse 11.3G 4.1G 7.3G 36% /mnt/shell/emulated
/dev/block/vold/179:49
29.0G 15.2G 12.4G 55% /mnt/media_rw/sdcard1
/dev/block/vold/179:49
29.0G 15.2G 12.4G 55% /mnt/secure/asec
/dev/fuse 29.0G 15.2G 12.4G 55% /storage/sdcard1
[B]/dev/fuse 29.0G 15.2G 12.4G 55% /data/media/0/DCIM[/B]

At this point I launched google camera (fresh).

Unfortunately I have this toast message popping up:

My impression is that the app can't access the directory. For this reason I edited this file: /etc/permissions/platform.xml to look as the following:

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2008 The Android Open Source Project

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->

<!-- This file is used to define the mappings between lower-level system
user and group IDs and the higher-level permission names managed
by the platform.

Be VERY careful when editing this file! Mistakes made here can open
big security holes.
-->
<permissions>

<!-- ================================================================== -->
<!-- ================================================================== -->
<!-- ================================================================== -->

<!-- The following tags are associating low-level group IDs with
permission names. By specifying such a mapping, you are saying
that any application process granted the given permission will
also be running with the given group ID attached to its process,
so it can perform any filesystem (read, write, execute) operations
allowed for that group. -->

<permission name="android.permission.BLUETOOTH_ADMIN" >
<group gid="net_bt_admin" />
</permission>

<permission name="android.permission.BLUETOOTH" >
<group gid="net_bt" />
</permission>

<permission name="android.permission.BLUETOOTH_STACK" >
<group gid="net_bt_stack" />
</permission>

<permission name="android.permission.NET_TUNNELING" >
<group gid="vpn" />
</permission>

<permission name="android.permission.INTERNET" >
<group gid="inet" />
</permission>

<permission name="android.permission.READ_LOGS" >
<group gid="log" />
</permission>

<permission name="android.permission.READ_EXTERNAL_STORAGE" >
<group gid="sdcard_r" />
</permission>

<permission name="android.permission.WRITE_EXTERNAL_STORAGE" >
<group gid="sdcard_r" />
<group gid="sdcard_rw" />
<group gid="media_rw" />
</permission>

<permission name="android.permission.ACCESS_ALL_EXTERNAL_STORAGE" >
<group gid="sdcard_r" />
<group gid="sdcard_rw" />
<group gid="sdcard_all" />
</permission>

<permission name="android.permission.WRITE_MEDIA_STORAGE" >
<group gid="media_rw" />
<group gid="sdcard_rw" />
</permission>

<permission name="android.permission.ACCESS_MTP" >
<group gid="mtp" />
</permission>

<permission name="android.permission.NET_ADMIN" >
<group gid="net_admin" />
</permission>

<!-- The group that /cache belongs to, linked to the permission
set on the applications that can access /cache -->
<permission name="android.permission.ACCESS_CACHE_FILESYSTEM" >
<group gid="cache" />
</permission>

<!-- RW permissions to any system resources owned by group 'diag'.
This is for carrier and manufacture diagnostics tools that must be
installable from the framework. Be careful. -->
<permission name="android.permission.DIAGNOSTIC" >
<group gid="input" />
<group gid="diag" />
</permission>

<!-- Group that can read detailed network usage statistics -->
<permission name="android.permission.READ_NETWORK_USAGE_HISTORY">
<group gid="net_bw_stats" />
</permission>

<!-- Group that can modify how network statistics are accounted -->
<permission name="android.permission.MODIFY_NETWORK_ACCOUNTING">
<group gid="net_bw_acct" />
</permission>

<permission name="android.permission.LOOP_RADIO" >
<group gid="loop_radio" />
</permission>

<!-- Hotword training apps sometimes need a GID to talk with low-level
hardware; give them audio for now until full HAL support is added. -->
<permission name="android.permission.MANAGE_VOICE_KEYPHRASES">
<group gid="audio" />
</permission>

<permission name="android.permission.ACCESS_FM_RADIO" >
<group gid="media" />
</permission>

<!-- ================================================================== -->
<!-- ================================================================== -->
<!-- ================================================================== -->

<!-- The following tags are assigning high-level permissions to specific
user IDs. These are used to allow specific core system users to
perform the given operations with the higher-level framework. For
example, we give a wide variety of permissions to the shell user
since that is the user the adb shell runs under and developers and
others should have a fairly open environment in which to
interact with the system. -->

<assign-permission name="android.permission.MODIFY_AUDIO_SETTINGS" uid="media" />
<assign-permission name="android.permission.ACCESS_SURFACE_FLINGER" uid="media" />
<assign-permission name="android.permission.WAKE_LOCK" uid="media" />
<assign-permission name="android.permission.UPDATE_DEVICE_STATS" uid="media" />
<assign-permission name="android.permission.UPDATE_APP_OPS_STATS" uid="media" />

<assign-permission name="android.permission.ACCESS_SURFACE_FLINGER" uid="graphics" />

<!-- This is a list of all the libraries available for application
code to link against. -->

<library name="android.test.runner"
file="/system/framework/android.test.runner.jar" />
<library name="javax.obex"
file="/system/framework/javax.obex.jar"/>
<library name="javax.btobex"
file="/system/framework/javax.btobex.jar"/>

<!-- These are the standard packages that are white-listed to always have internet
access while in power save mode, even if they aren't in the foreground. -->
<allow-in-power-save package="com.android.providers.downloads" />

</permissions>

Rebooted (and remounted...), but still same issue.

What am I doing wrong? What can I do to solve this issue?

my phone: Samsung i9300

running CM 12.1-20150426-UNOFFICIAL-i9300

android version: 5.1.1

Thanks,

Niko