How to: Format your uSD-Card to share space with android

answered 2016-07-31 18:04:53 +0300

gcobb
1660 ●19 ●31 ●35

I have created a variant of this for use on the Jolla C, with SailfishOS 2.0.2.43 (Aurajoki). This has the following main differences with the original solution @chemist created:

1. The SDcard is formatted to ext4 instead of btrfs (as there is no btrfs support in this Sailfish version). I also kept a conventional partition layout (to make it more likely other systems can easily mount the card. although they need to support ext4).
2. The android directory that is overlaid is /home/nemo/android_storage instead of /data/media.
3. Bind mounts are used, instead of btrfs subvolume mounts. The Android directory is hidden in an attempt to prevent tracker indexing the files twice.

Here is my replacement for @chemist's instructions:

preparing the sdcard, should only be needed once!

first dosystemctl stop aliendalvik.service then follow this list

1. umount /dev/mmcblk1p1 - unmount the card might be another /dev or even more than one
2. mkfs.ext4 /dev/mmcblk1p1 - format the card
3. mount /dev/mmcblk1p1 /media/sdcard
4. cd /media/sdcard
5. mkdir .android - create folder called .android - this is hidden (starts with a dot) so it does not appear in directory listings

6. I like to create a file on the card to remind me what I have done: so create a file called Android.README and fill it with:

   Android files are contained in a hidden directory called .android

   See https://together.jolla.com/question/40802/how-to-format-your-usd-card-to-btrfs-and-share-space-with-android/

7. I also like to create a file with a unique name to let me easily check that Android apps are seeing the expected SD card. Something like: touch .android/GRC-128GB-SD.android

8. chown -R nemo:nemo .android/
9. chmod -R a=rwX .android/
10. cp -r -a -v /home/nemo/android_storage/* /media/sdcard/.android
11. cd ..
12. umount /dev/mmcblk1p1

preparing the system

• The next step requires knowing the Filesystem UUID for the SDcard filesystem. You can get it using lsblk -no UUID /dev/mmcblk1p1. The UUID is a string like 12345678-9abc-def0-1234-56789abcdef0. This string must be used instead of the string UUID-HERE in the file below (two occurrences).
• create (as in do create not a command) /etc/systemd/system/home-nemo-android_storage.mount and fill with:

#

[Unit]
Description=SD card bind mount for Android
ConditionPathExists=/dev/mmcblk1p1
ConditionPathExists=!/tmp/os-update-running
ConditionPathIsDirectory=/home/nemo/android_storage/
ConditionPathIsMountPoint=/media/sdcard/UUID-HERE/
Requires=local-fs.target systemd-user-sessions.service
Before=aliendalvik.service
After=mount-sd@mmcblk1p1.service
BindsTo=mount-sd@mmcblk1p1.service

[Mount]
What=/media/sdcard/UUID-HERE/.android/
Where=/home/nemo/android_storage/
Options=bind

[Install]
WantedBy=local-fs.target aliendalvik.service

Then run systemctl enable home-nemo-android_storage.mount.

• the mount file gets started every time aliendalvik is started and stops aliendalvik when it gets stopped, on boot it prevents aliendalvik from starting if it is not started yet but waits for the local-fs to be settled and actually having a mountpoint

• If you put a different SD card in, the mount file will do nothing (because the UUID does not match). The original /home/nemo/android_storage will be used. You can repeat the steps from the top, of course, for the new card.

answered 2014-06-12 19:39:58 +0300

Vuubi
1443 ●12 ●24 ●28

This is how you can make chemist's version of systemd service unit (androidsdcard.service) into systemd mount unit.

First, create /etc/systemd/system/data-media.mount file:

[Unit]
Description=SD card btrfs subvolume for Android
ConditionPathExists=/dev/mmcblk1
ConditionPathIsDirectory=/data/media
Requires=local-fs.target
Before=aliendalvik.service
After=local-fs.target mount-sd@mmcblk1.service
BindsTo=mount-sd@mmcblk1.service

[Mount]
What=/dev/mmcblk1
Where=/data/media
Options=subvol=android,compress,dirsync,noatime,users

[Install]
WantedBy=local-fs.target aliendalvik.service

Second, create /etc/systemd/system/aliendalvik.service.d/sdcard.conf file:

[Unit] 
PartOf=data-media.mount

Then run systemctl enable data-media.mount (androidsdcard.service must be disabled before that).

answered 2014-06-11 12:47:51 +0300

alci
1024 ●26 ●38 ●48

If you want to use the sdcard as an extended memory and put your /home on it, you need to make sure it is mounted at the right moment and available for the ambiance setting, etc...

I tried the solution mentioned by the OP, but it implies modifying a system script, which is not upgrade-proof. Moreover, the script is not called early enough to let ambiance and some settings work...

I have found that a much solution is this one: Maemo thread to mount sdcard as /home I am using this for 2 month and a half now, 2 upgrades, and it has worked reliably for now. Of course, YMMV :-)

answered 2015-02-22 18:36:23 +0300

jolladiho
2932 ●45 ●74 ●67

updated 2015-02-24 21:24:04 +0300

This is a workaround for 1.1.2. Someone changed it from a comment to an answer, thanks for this. I wrote it as comment, before chemist published the fix for 1.1.2 in the top thread. I recommend to use the fix from chemist.

As difference to the fix: No changes to delivered system files are necessary. You need the script and a change in the androidsdcard.service.

After reading comments from top thread, I wrote a little script, for all, who use a .service for the android-sd mount, like described in top thread. It puts some messages in the journalctl if you use it with 'mydebug=1'. Change the 'mymountoptions' var to your needs (the subvol entry at minimum!). The script waits for all alien processes, before it stops the aliendalvik.service and .path. Then it mounts the subvol to /data/media and starts the aliendalvik.path again. Use at your own risk.

If you make some mistakes, you have to know, how to start the recovery shell, mount the root subvol and remove a systemd service in that environment.

The script: /usr/local/bin/tmpfix-alien-mount-1.1.2.15.sh

#!/bin/bash
# dirty but handy
# stop android after startup, do mount and restart aliendalvik.path
# set the vars to your needs (user variables)
mymountoptions="subvol=.android,compress,dirsync,noatime,users,autodefrag,rw"
mydebug=1 # set to 1 for logging (jounalctl | grep tmpfix-alien-mount)
# no changes below needed
myservices="alien_audio_server aliensensorserver alien_bridge_server alien_gps_server alien_keyboard_server"
[ $mydebug == 1 ] && systemd-cat -t tmpfix-alien-mount /bin/echo "started with: PID=$$"
for i in $myservices
do
  mycount=$(/bin/ps -ef | /bin/grep -v grep | /bin/grep $i | wc -l)
  while [ $mycount -lt 1 ]
  do
    /bin/sleep 1
    mycount=$(/bin/ps -ef | /bin/grep -v grep | /bin/grep $i | wc -l)
  done
  [ $mydebug == 1 ] && systemd-cat -t tmpfix-alien-mount /bin/echo "$i found, counts: $mycount"
done
[ $mydebug == 1 ] && systemd-cat -t mount-sd.custom /bin/echo "all aliendalvik processes found."
/bin/sleep 1
systemctl stop aliendalvik.service
/bin/sleep 1
systemctl stop aliendalvik.path
[ $mydebug == 1 ] && systemd-cat -t tmpfix-alien-mount /bin/echo "aliendalvik stopped."
/bin/sleep 1
/bin/mount -o $mymountoptions /dev/mmcblk1 /data/media
[ $mydebug == 1 ] && systemd-cat -t tmpfix-alien-mount /bin/echo "mount with $mymountoptions done."
/bin/sleep 1
systemctl start aliendalvik.path
[ $mydebug == 1 ] && systemd-cat -t tmpfix-alien-mount /bin/echo "aliendalvik.path restarted, all done, exit."

I put it in /usr/local/bin and make it executable for user/group root.

In my androidsdcard.service I replaced the 'ExecStart' and 'ExecStop' part with.

ExecStart=/usr/local/bin/tmpfix-alien-mount-1.1.2.15.sh
ExecStop=/bin/umount /data/media

My Jolla did not shutdown correctly as I tried to add a 'systemctl stop aliendalvik.service' and .path to the ExecStop.

answered 2015-12-30 18:14:22 +0300

tyler
1250 ●20 ●26 ●31

I meet a wired problem: if I was downloading to card through an android app, software cannot write/read sd card after some time.

$ cd android_storage/    # another android app is downloading in background
$ while true; do
> date
> date > write_test
> sleep 3
> done
Wed Dec 30 23:46:46 CST 2015
Wed Dec 30 23:46:49 CST 2015
Wed Dec 30 23:46:52 CST 2015
Wed Dec 30 23:46:55 CST 2015
Wed Dec 30 23:46:58 CST 2015
Wed Dec 30 23:47:01 CST 2015
Wed Dec 30 23:47:04 CST 2015
Wed Dec 30 23:47:07 CST 2015
Wed Dec 30 23:47:10 CST 2015
Wed Dec 30 23:47:13 CST 2015    # frozen forever, android app downloading frozen
^C
$ ls    # frozen here forever

answered 2014-06-11 12:32:11 +0300

RobNas
1151 ●40 ●48 ●53

updated 2014-06-13 14:21:14 +0300

This answer is obsolete now. I've left the part of editing with VIM, for anyone who's interested. To create a file, just type in terminal: touch /to/path/filename.extension Where "/to/path/" is the location of where the file needs to be located, and "filename.extension" is, surprisingly, the filename and extension. I've edited it with VIM. How to:
pkcon install zypper - if you haven't installed vim yet
zypper in vim - if you haven't installed vim yet
vim /usr/sbin/mount-sd.sh
To edit in vim, type "i"
Now you can type your text. After editing, get out of edit-mode, by pressing ESC twice. Then enter shift twice (capslocking it) and tap z twice ("ZZ"is the command for vim to save and exit).