Alternative to Partitioning your SD Card? - G1 Android Development

Is there anyone out there who has simply created a image of an ext2 filesystem rather than physically partitioning the SD card?
I was thinking of creating an appstorage.img file and mounting via the loopback device in order to store apps on the SD card. This would allow me to keep the whole card as FAT32.
So on a linux computer, I'd do:
dd if=/dev/zero of=appstorage.img seek=500999999 bs=1 count=1
mke2fs -F appstorage.img
Then I'd copy the appstorage.img onto the SD card.
Finally I'd have to mount the new filesystem image on the phone....so using the terminal emulator app on the phone itself, I'd do something like:
mkdir /appstorage
mount -o loop appstorage.img /appstorage
mv /data/app/* /appstorage
ln -s /appstorage /data/app/
Not sure if I'd need to load an ext2 module first. If so, I'd want to insert that on bootup of the phone. Would I insert that in one of the rc.init or rc.local files to be run at boot?
Same for the mount command?

The problem is that at boot time, /data/app needs to be available the same time the ext2.ko module of a non-rooted phone becomes available.
JesusFreke added ext2.ko support into somewhere before that point. (I just checked, it's in the system.img flash file; found it in JFs build environment)
In order to use your solution, which many people including me have contemplated, you need to have loop.ko available at that very point in time. That means building your own system.img image file and flashing it with fastboot.
Hope this helps!

Thanks...it does help, although that probably puts it beyond my capabilities. I don't think I'm up to building a custom system.img....maybe it isn't as difficult as I think.
This is similar to what LucidREM did, building a custom mod to the JF build?
Wonder if this would be included as part of the next official Android release from Google/TMobile? Obviously they can't/won't want to partition people's SD cards to expand app storage....seems the filesystem image is the only way to go.

Autarkis said:
The problem is that at boot time, /data/app needs to be available the same time the ext2.ko module of a non-rooted phone becomes available.
JesusFreke added ext2.ko support into somewhere before that point. (I just checked, it's in the system.img flash file; found it in JFs build environment)
In order to use your solution, which many people including me have contemplated, you need to have loop.ko available at that very point in time. That means building your own system.img image file and flashing it with fastboot.
Click to expand...
Click to collapse
Hmm...wait a second here....maybe I don't fully understand.
But looking at the modified init.rc from a thread about moving apps to the SD card, it appears that it is mounting files via loopback and then later directly doing the insmod of the ext2.ko module prior to mounting the ext2 partition on the SD card. Take a look:
Code:
on system
mount cramfs [email protected]/system/modules/modules.cramfs /system/modules ro
mount cramfs [email protected]/system/xbin/xbin.cramfs /system/xbin ro
insmod /system/modules/2.6.25-01843-gfea26b0/kernel/fs/ext2/ext2.ko
mknod /dev/mmcblk0p2 b 179 2 1000
mount ext2 /dev/mmcblk0p2 /system/sd noatime nodiratime
Am I missing something? Are the first two lines utilizing the loopback device already, meaning it would have been loaded previously?

bump. (very curious about this thread)

A bump from me too - last night I had to format my 8Gb SD card back to Fat32 and put myself back to the standard JF RC9 build - my G1 stopped reading my SD card's Fat32 partition and no matter how many times I formatted it or re-created the partition, nothing would work.
Only after FULLY formatting and loosing my my Ext2 partition on it did it start reading it again, causing my phone to fail to boot until I put the standard JF build back on and do a full factory reset.
This is a pretty fundamental flaw of the phone - is there really a technical reason why app's can't be run off a Fat32 SD card?

I am curious to this topic as well...

wont u need to edit a file? so it would auto remount if you reboot the phone?

For those that have installed the Debian distro on their phone, you are doing almost the exact same thing. You create a debian.img file and format it as an ext2 filesystem.
Then you mount it via the loopback device as an ext2 filesystem. But that is after your phone is already booted up in Android and running.
So the question is when the loopback module for the kernel gets loaded. From Autarkis post, he indicates the loading of the loop.ko module is a problem and would require a custom boot image.
But it looks to me like the loopback module is already loaded when init.rc is called...so I'm confused as to why this won't work.
I briefly tried it on the 1GB card that came with the phone, but gave up after a few minutes. Didn't seem to be working. Dunno...maybe I'll give it another go. But I have to believe that someone else has already tried this rather than go through the pain of partitioning.

Wouldn't you then have the same disadvantage as debian.img on FAT? i.e. that you couldn't unmount the FAT (on connection to a PC) as the ext2 partition image was still mounted.
I was thinking about doing the opposite; moving my debian.img over to within the (ext2) app partition to get around this very issue, I can't really work out why you are trying to introduce this problem!

digitalspaghetti said:
A bump from me too - last night I had to format my 8Gb SD card back to Fat32 and put myself back to the standard JF RC9 build - my G1 stopped reading my SD card's Fat32 partition and no matter how many times I formatted it or re-created the partition, nothing would work.
Only after FULLY formatting and loosing my my Ext2 partition on it did it start reading it again, causing my phone to fail to boot until I put the standard JF build back on and do a full factory reset.
This is a pretty fundamental flaw of the phone - is there really a technical reason why app's can't be run off a Fat32 SD card?
Click to expand...
Click to collapse
I think there's a couple reasons the phone can't install apps on a fat32 sd card. The biggest one is that you can't make symlinks to/from a FAT32 file system, meaning even if you were google and wanted to make it possible, it'd likely have to be an all or nothing deal and they didn't want to make the phone unusable/crash without an SD. For the average hacker here, it'd just be too difficult to make the operating system read apps from FAT32.

Related

"Stale NFS file handle"

Hi all
I have all my apps and data moved to the sdcard a while back but my phone crashed and I decided to move only the apps to the sdcard.
I'm trying remove the /system/sd/data folder on the sdcard and keeps getting that error message. How to fix it?
Thanks
This should only happen if an NFS export is mounted to a linux box of some sort, and that export has changed or otherwise become inaccessible.
any idea how to fix it?
i have this problem, i'm not able to delete the data folder beacause of that error. :/
your ext2 partition is corrupted. this happens quite a lot if data is moved to the sdcard. boot up linux and run fsck on the sdcard and that should fix it.
cool. I'll give that a try.
Thanks
I'm having this problem too. Can you provide some basic instructions for how to mount and fix under linux? I have an ubuntu vmware image I can boot to on my windows pc and a usb card reader. Will that suffice?
When you plug the card into an ubuntu box it should automatically mount it as the next available drive. You'll have to figure out what device node the card shows up as, unmount it (umount /dev/<insert device name here>), and then run a filesystem check (fsck /dev/<insert device name here>) on the unmounted card. The utility will report various problems about "inodes" which you will want to say yes to fix. Once it has run through the file system should be in a consistent state and ready for use again.
You run the risk of losing stuff written to the card (which is probably corrupt anyways) when you run the fsck so you may want to take a copy of the data first.
On a side note: I am not sure what the default mount options are listed for moving the stuff onto the sd card in the faqs but I suspect it may help prevent corruption to mount the card on android with the sync option. Though, this will definitely slow writes to the card. It would definitely be a bad idea to remove the card while your G1 is running either way.
equid0x said:
On a side note: I am not sure what the default mount options are listed for moving the stuff onto the sd card in the faqs but I suspect it may help prevent corruption to mount the card on android with the sync option. Though, this will definitely slow writes to the card. It would definitely be a bad idea to remove the card while your G1 is running either way.
Click to expand...
Click to collapse
I was thinking of using the sync option, but then I read this at http://linux.die.net/man/8/mount:
sync
All I/O to the file system should be done synchronously. In case of media with limited number of write cycles (e.g. some flash drives) "sync" may cause life-cycle shortening.
Click to expand...
Click to collapse
Busybox seems to have an fsck command built in, but I don't think all the supporting stuff is there. I'd like to have a way to fsck my ext2 partition while on the go and not near my linux box.
I know that you can't fsck without unmounting the partition and of course it would be bad to unmount the partition with apps on it while the phone is running, but I was thinking it would be nice to be able to boot into the recovery console.
I tried this and attempted to do a fsck on /dev/mmcblk0p2 with the fsck in busybox as follows:
Code:
busybox fsck -t ext2 /dev/mmcblk0p2
But the error I got was that fsck.ext2, which is the actual executable that should be used, isn't there.
What would it take to get this onto the system so that I could boot into recovery and do a quick fsck and then reboot back into phone mode?
I was thinking of using the sync option, but then I read this at http://linux.die.net/man/8/mount:
Click to expand...
Click to collapse
Where flash lifetime is concerned... I agree, this will certainly have some impact. However, the amount of wear concerned really depends on the number of write cycles the particular flash you are writing to can handle, and how good any wear leveling in the memory controller is. Modern flash memory will likely last on the order of years even with tons of writing going on. If all you are moving to the card are the apps, that data will likely be written once (or maybe a few times over the life of an app) and only re-read from that point forward. The caching will eventually commit any data in the buffer to "disk" regardless of how much is actually there. The idea is to line up all the writes so they can be done efficiently. Where ext3 is concerned, the commit interval is 5 seconds by default, I am not sure what it was in ext2 but I imagine it is similar. Ext2 is not really a flash optimized filesystem, but it is readily available on basically any linux distro, and is supported on Android. A better fs for flash drives where write cycles are an issue might be something like jffs2 or yaffs.
At any rate, sd cards are cheap. Why not just throw it away when it starts to die?
But the error I got was that fsck.ext2, which is the actual executable that should be used, isn't there.
What would it take to get this onto the system so that I could boot into recovery and do a quick fsck and then reboot back into phone mode?
Click to expand...
Click to collapse
You would have to compile an ARM6 compatible version of fsck and get it onto the recovery partition so you could run it.
just turn off your phone, pull out the sdcard, boot on a linux os and
then in console type :
fsck -p /dev/your_ext2_partition
Is there any way to clear this error message on a windows xp computer?
Maybe use pargon partion manager, but where do I go to fix it in pargon?
equid0x said:
Ext2 is not really a flash optimized filesystem, but it is readily available on basically any linux distro, and is supported on Android. A better fs for flash drives where write cycles are an issue might be something like jffs2 or yaffs.
Click to expand...
Click to collapse
Hmm... Well, we know that yaffs is supported on Android because that's what the onboard storage uses. So I wonder why the tutorial for apps-on-sdcard suggests creating an ext2 partition? Couldn't we create a yaffs partition on the sdcard and use that instead?
Maybe because yaffs isn't as commonly supported in non-Android partitioning tools (which you would have to use to set up the card initially)?
In any case, if there's no real downside to having the partition be yaffs, how can I go about formatting it as such? I don't recall seeing such an option on gParted or anything, but then again I didn't look that carefully.
So can anyone clue me into how I might add yaffs/yaffs2 support to my desktop linux box? I'd like to try using a yaffs2 partition rather than ext2 to see if I get better reliability, but I need to add support for that filesystem first. Can't seem to figure out how to do that quite yet...
You will likely need to create the partition from the terminal using something like fdisk or cfdisk which will allow you to select the proper filesystem ID. The command for creating the filesystem is mkyaffs. The fstab in android will need to be modified to enable mount of this file system at boot. You will need to install all of the yaffs support tools on a linux desktop to get access to the mkyaffs command.
Yaffs is designed to be used directly on NAND or NOR flash memory (not abstracted through the controller built into an SD card) but it may work anyways. I am not very familiar with the specifics of this particular FS. Most of these flash filesystems are designed to provide a bootable root filesystem for an embedded device.
Yaffs kernel support can be built into a custom kernel with the instructions here:
http://yaffs.net/howto-incorporate-yaffs
Its not likely you will find pre-made packages for any of this in a common distro like Ubuntu. So, you will need to know how to compile it all by hand. A good starting point for a lot of linux info is The Linux Documentation Project at:
http://www.tldp.org/
FWIW I have built homebrew linux based routers for dual ISPs, IPSEC VPN and the like using a lightly modified version of CentOS and 4GB CF cards plugged into an ATA adapter. I used EXT2 on these and they were in production use at a small 13 server farm for a couple of years before being replaced with newer equipment without any failures whatsoever.
I have also used CF cards in small 200Mhz cube PCs as basic web kiosks for extended periods of time without any failures as well.
Under normal usage patterns on a mobile device probably does not require a large amount of writes in the grand scheme of things. I'd say it is fairly likely that your card will outlive the device you are using it in regardless of the filesystem in use.
If you are seeing lots of corruption I would suspect a flakey/failing SD card or some other hardware related problem. It definitely pays to buy high quality flash media. I would also suggest not allowing the phone to constantly run dead if you know things are being written to the SD card, since random power failures during a write to flash can permanently damage the media.

New and improved Apps to SD(more stable, more powerful, etc) Tutorial

Well, some of you may have heard my ramblings around here that I've been working with some of the devs here(JF and MartinFick deserve major praise, probably more than me) on getting a better way to do the whole apps to sd thing.
After 3 days of talking/discussing/working on it, I've finally reached the fruits of that investigation and thought I'd share. This new method uses the filesystem unionfs to essentially meld the /data directory with the /system/sd directory, so that they appear to be one. This has the potential to allow users to move specific apps to or from the sd card, is far more stable than the normal symlink method(will still boot, etc even if there's no SD card) and should be easier to set up. Now, onto the tutorial of setting this up.
BIG DISCLAIMER NOTE: This is a major hack of the phone and it is fully possible that it will break your phone(I've seen no permanently bricked phones but that doesn't make it impossible). Use this method, and my app along with it at your own risk.
REQUIREMENTS:
1: This only works on JF(possibly only on 1.5, not sure about the others) and The Dude's v.1.0 or greater. The Dude's 1.0 or greater actually does the steps in this tutorial for you so you can just run appstosd2 and set it all up from there if you're using his ROM.
2: This still requires you to have 2 partitions set up, first FAT32 and second ext2. Although you can use the appstosd2 app attached to this post and available in the market for $0.99 which will partition the card for you.
3: If you want your apps to go to the sd card, you must have a directory "/system/sd/app" If you didn't have apps to sd before on the ext2 partition do the following in terminal emulator or run my appstosd2 app after finishing the tutorial:
Code:
su
mkdir /system/sd/app
If you want the private-apps, or dalvik-cache moved you can replace "app" in that code with ""app-private", or "dalvik-cache" respectively. Do not copy "data" to the sd card. My script will delete it on the next reboot.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
Alright, first there's some files you need.
1: init.rc in .zip attached to this thread
2: a2sd.sh in .zip attached to this thread
All the above listed files should be put on your sd card(my tutorial will assume they are in the root directory of the sdcard(the topmost folder)
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
If you need to undo the normal apps to SD first do the following in the recovery terminal(it's not strictly necessary but I'd recommend it):
Code:
mount data
rm /data/app
mkdir /data/app
if you moved the dalvik cache, repeat steps 2-3 with "dalvik-cache" instead of app. Ditto with "data" for the data cache.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
Then go to terminal emulator and type the following:
Code:
su
cp /sdcard/init.rc /data/
cp /sdcard/a2sd.sh /data/
Then reboot and you're set. By default all future apps are installed to the sd card. In order to move an app to the internal memory do the following in terminal emulator:
Code:
su
cp /system/sd/app/[the app you want to move] /system/intmem/app/
rm /system/sd/app/[the app you want to move]
I will be incorporating this into my appstosd app soon(probably as a JF and TheDude-only version until the rest of the devs get on board).
I have included a copy of appstosd 2, which will copy all apps from internal memory to the sd card with an option to remove them from the internal memory. This will only work if you have followed this tutorial.
If you don't have partitions set up, appstosd2 will now do that for you with user-set partition sizes.
NOTE: If you're using The Dude's ROM and find yourself with an outdated version of this since he doesn't always update his ROMs at the same time I update this, do the following in terminal emulator to update(after putting a2sd.sh from the attached a2sd.zip on your sdcard):
Code:
su
mount -o remount,rw -t yaffs2 /dev/block/mtdblock3 /system
rm /system/bin/a2sd.sh
cp /sdcard/a2sd.sh /system/bin/
reboot
For JF1.5, do the following to update:
Code:
su
rm /system/intmem/a2sd.sh
rm /system/intmem/init.rc
cp /sdcard/a2sd.sh /system/intmem/
cp /sdcard/init.rc /system/intmem/
reboot
NOTE FOR UPDATERS: If you had your data on the sdcard(/system/sd/data), it WILL GET DELETED with the new version. This is a necessity in order to get both wallpaper and protected apps working. I recommend moving it back to the phone.
EDIT: And here's another tutorial from ThatsBS(might be easier for the less tech savvy to follow?):
I am still learning a lot everyday from this forum. So for people new to this process let me noobify it, if I can, as I am one too.
Start by reading the first page!! Get all the stuff you need from page 1. (apps2sd2.zip and a2sd.zip )
I started from a fresh wipe and flash of jf1.51 adp.
A newly formatted fat32, non partitioned sd.
Put the init.rc and app2sd.sh on the sd (the files NOT the zip)
Then go to the terminal emulator and typed:
su
cp /sdcard/init.rc /data/
cp /sdcard/a2sd.sh /data/
Then reboot
Next I ran the apps2sd 2 app. It will ask you how much to you want to partition. I did 3000mb the first successful time and the dreaded low mem notice would not leave the status bar. I have read not to make it more then 1500mb. Have a good connection, dont force close it. It will reboot.
Next, after the reboot, I ran the apps2sd 2 app again and pressed "copy apps to sd" (let it do its thing)
Reboot.
Next I went back to the emulator and typed:
su
mkdir /system/sd/app-private
mkdir /system/sd/dalvik-cache
Reboot.
Go back to the apps2sd 2 app and hit move dalvik-cache.
Reboot for good measure and your done.
I did this in about 10 mins. Worked flawlessly.
I have a ?, if i have been using your app what dod i do diferent or what should i change?
Thanks
Good job, thanks!
[email protected] said:
will still boot, etc even if there's no sim card
Click to expand...
Click to collapse
You mean SD card?
[email protected] said:
Alright, first there's some files you need.
1: unionfs.ko from here:
Click to expand...
Click to collapse
JF1.5 build has already unionfs.ko in it, doesn't it? Is there any difference between this unionfs.ko and the one included?
1. I hear unionfs is not really stable at this point, is it true?
2. Why do you want to move the whole /data folder to sd, instead of just /data/app, /data/app-private?
3. You might want to add a command to remove previous app2sd changes (i.e. delete symlinks, create folders.)
4. How do you put selected apps to internal memory after this? Copying to /data will copy to sd card again.
The whole idea is really interesting! Thank you for your work!
ArmandHammer said:
I have a ?, if i have been using your app what dod i do diferent or what should i change?
Thanks
Click to expand...
Click to collapse
You don't have to do anything different. It will find all the apps you put on the sd card. If you want to set the phone back to normal(so the phone memory apps can still be there), you can do the following in the recovery terminal:
Code:
mount data
rm /data/app
rm /data/dalvik-cache (only if you moved the dalvik-cache)
mkdir /data/app
mkdir /data/dalvik-cache
@Dimath: yes, I did mean SD card, good catch
1:JF didn't mention it and from a little bit of using it, it seems stable to me. Plus, no matter how much I've screwed up, I haven't managed to boot loop my phone yet.
2: You could just mount those independently. I might end up doing that eventually but for now the way it is works for reasons I'll get to.
3: True, although it's not strictly necessary. If apps2sd already works, this won't break it. I'll put in a guide on undoing the symlink method
4: Actually, no. My script sets the internal memory as the main file system in the union, so apps automatically go there. Moving apps to the sd card just involves copying them to /system/sd.
Ok, just a little confusing.
I didn't use the apps2sd to move apps over to my SD card. What I did was set it with the busybox ls command. I guess that's the symlink.
My question is, if I didn't use apps2sd, can I still use your method? I also moved the dalvik cache also, everything works fine for me now, my apps go directly to the SD card when installing since my memory stays at around 65 MB no matter what I do.
Just need some laymen terms to help me understand that if I'm NOT using apps2sd, and I just linked them with the recovery method, what's my pitfalls / advantages?
Thanks.
larrygates said:
Ok, just a little confusing.
I didn't use the apps2sd to move apps over to my SD card. What I did was set it with the busybox ls command. I guess that's the symlink.
My question is, if I didn't use apps2sd, can I still use your method? I also moved the dalvik cache also, everything works fine for me now, my apps go directly to the SD card when installing since my memory stays at around 65 MB no matter what I do.
Just need some laymen terms to help me understand that if I'm NOT using apps2sd, and I just linked them with the recovery method, what's my pitfalls / advantages?
Thanks.
Click to expand...
Click to collapse
Yes, any other method of apps to sd currently uses the same symlink method, so following the directions as if you installed my app will work. A note though is that all future apps will install to the internal memory by default. I did that because it's MUCH easier to move apps from the memory to the sd card than vice versa. You can use the code I posted if you want it the other way around.
would this also work for /data/data and app-private?
or is this particular setup only for dalvik-cache and app?
oh and before I do this, just wondering, so in theory, since I have a 1.5GB ext2 partition, my free memory will be 1.573GB (1.5GB + 73Mb internal)? The internal memory will just run down and switch over to the sdcard when needed (but be seen as one filesystem)?
andonnguyen said:
would this also work for /data/data and app-private?
or is this particular setup only for dalvik-cache and app?
Click to expand...
Click to collapse
This works for the whole /data folder and everything under it. Everything is automatically installed to the phone memory right now so you can just move over anything you don't want on it(will be making an app to do this automatically)
EDIT: oh and anything you already moved over to the sd card will still show up.
Code:
su
mount -o remount,rw /dev/block/mtdblock3 /system
cp /sdcard/unionfs.ko /system/
cp /sdcard/init.rc /data/
cp /runme.sh /data/
cp /sdcard/a2sd.sh /data/
I see, when I run these lines of code (I can do this from adb also right using adb remount) this IS the new symlink method. It's just all at one time without me having to manually link anything.
Right?
larrygates said:
Code:
su
mount -o remount,rw /dev/block/mtdblock3 /system
cp /sdcard/unionfs.ko /system/
cp /sdcard/init.rc /data/
cp /runme.sh /data/
cp /sdcard/a2sd.sh /data/
I see, when I run these lines of code (I can do this from adb also right using adb remount) this IS the new symlink method. It's just all at one time without me having to manually link anything.
Right?
Click to expand...
Click to collapse
Wrong, no symlinks here. Pure unionfs goodness. Basically it convinces the operating system that /data and /system/sd are the same thing. So anything that's on /system/sd shows up under /data but everything that's normally under /data is still there. Think of it like what happens in windows when you merge folders with the same name, but in this case in actuality everything stays exactly where it was.
New news: If you haven't seen it, I updated this tutorial(and the scripts with it) quite a bit and would now consider it to be completely fully functional.
Also The Dude will be sending me an advance copy of his next ROM tomorrow to verify it works. In his build the apps to sd will be automatic, with no user setup(although if you want apps on the sd card you'll have to make an app directory under /system/sd(mkdir /system/sd/app), ditto for dalvik-cache and data).
Finally, I will attempt to add this into my apps to sd app tonight, thus rounding out everything I can do.
After all this, the only thing left is for Haykuro to build it into his ROM and me to make an app to move specific apps to/from the sd card automatically.
This will no doubt be the method of choice in no time. Great work. Sticky?
If anyone dl'd the latest version(that fixed the race condition, etc), please download the one I just put up. I made that one in windows and I believe the funky carraige return(that indicates a new line) that windows uses screwed it up
So I got some kind of error, and I don't know what is going on.
I put in all the lines in the terminal emulator app..
but after line cp /runme.sh /data/ it gives me an error
it says "cp: cannot stat '/runme.sh': No such file or directory
Any help? I rooted my phone just so I could run my apps off of my SD card.. and now I can't figure out how to get it to work. Somebody help me please.
GTASouthPark said:
So I got some kind of error, and I don't know what is going on.
I put in all the lines in the terminal emulator app..
but after line cp /runme.sh /data/ it gives me an error
it says "cp: cannot stat '/runme.sh': No such file or directory
Any help? I rooted my phone just so I could run my apps off of my SD card.. and now I can't figure out how to get it to work. Somebody help me please.
Click to expand...
Click to collapse
Which ROM is this? JF1.5 should have runme.sh there...
[email protected] said:
Which ROM is this? JF1.5 should have runme.sh there...
Click to expand...
Click to collapse
Ok, I am going to re-partition my memory card.. and then re flash to JF1.5 and try it again.
Just tried it, one issue I'm seeing is android seems to install [email protected]@[email protected] into /system/intmem/dalvik-cache at boot. Is there anyway to have that only in my dalvik-cache on the sdcard?
Its a fairly large file at 3megs so I want it to reside solely on the sdcard and even if I delete it from intmem, whenever I reboot it gets added again.
Now when I display the internal phone storage from the settings menu, it shows up at 835 megs.
I wonder if this is possible to use unionfs and make an ext2 fs object as a file on the FAT fs. That way no 2nd partition is necessary. Plus, if you remove the sdcard, everything will still work.
Maybe we could combine unionfs and this method that uses an ext2 image on the fat32 for apps to sd.
http://forum.xda-developers.com/showpost.php?p=3402947&postcount=687
mkefs can be downloaded here:
http://sites.google.com/site/juanjosec/android
dwang said:
I wonder if this is possible to use unionfs and make an ext2 fs object as a file on the FAT fs. That way no 2nd partition is necessary. Plus, if you remove the sdcard, everything will still work.
Maybe we could combine unionfs and this method that uses an ext2 image on the fat32 for apps to sd.
http://forum.xda-developers.com/showpost.php?p=3402947&postcount=687
mkefs can be downloaded here:
http://sites.google.com/site/juanjosec/android
Click to expand...
Click to collapse
I've been looking at that possibility with JF and MartinFick as well, seems like it could be a good plan but I wanted to get this bit done first. It's a good point about the dalvik-cache, but in order to fix it JF(in this case) would have to change /init.rc to make sure to do this bit before building the dalvik-cache.
Can't download apps from market
hmm so I didn't hit any errors when doing this, but afterwards I am unable to download any apps from the market. It just continually says "Starting Download..." Everything else seems to work well.
I had this same issue when I tried to manually setup apps to sd using the symbolic links. I narrowed the issue down and figured out this only occurred after I moved the dalvik-cache over to the sd card. I'm assuming I'm doing something wrong, but can't seem to figure it out. Any pointers in a general direction would be most helpful
I'm using JFv1.50 ADP1.5, not the modded version by LucidREM. For some reason the bootloader couldn't pickup his version on my phone and --edit-- I'm pretty sure I have the SD card partitioned correctly... everything else seemed to work ok. The ext2 partition shows up as the correct size
*EDIT* So apparently my issue was the SD card as well. Just did a format of the sd card and it fixed it. I also formatted data and cache (alt+w in recovery mode). Thanks MarcusMaximus!
[email protected] said:
New news: If you haven't seen it, I updated this tutorial(and the scripts with it) quite a bit and would now consider it to be completely fully functional.
Also The Dude will be sending me an advance copy of his next ROM tomorrow to verify it works. In his build the apps to sd will be automatic, with no user setup(although if you want apps on the sd card you'll have to make an app directory under /system/sd(mkdir /system/sd/app), ditto for dalvik-cache and data).
Finally, I will attempt to add this into my apps to sd app tonight, thus rounding out everything I can do.
After all this, the only thing left is for Haykuro to build it into his ROM and me to make an app to move specific apps to/from the sd card automatically.
Click to expand...
Click to collapse
If I have apps2SD and the dalvik-cache both moved on the dudes builds already, do I still have to create those directories or will my existing setup still work fine? I would like to know what kind of issues I may run into when the dude releases .95 with this (hopefully, not getting my hopes up just in case).

data2sd

Hi All,
Here is my first contribution to the community, hope it is useful!
I've rezzed up a construct to produce a new /data on sd. It makes use of a second partition formatted ext2 or ext3 mounted to /system/sd with /system/sd/data then mounted over /data.
I've included a lengthy readme file which should explain things in greater detail.
Read the readme first to get a list of dirs & files this construct adds to the /data, then copy the files as explained and off you go!
currently my /data "volume" is 2GB and all is lovely!
Things to note:
I'm rom JF1.51 ADP1 CRB43, the sdcard is 8gb class6
The sd /data contains several scripts of my own design which if not needed can be deleted. I include my modified bootdeb.sh script as it mounts to /data/local/mnt/debian vs /data/local/mnt (that is a script I modified for my own needs which you may find useful)
Feel free to adjust any of the scripts according to your needs. Just note that if I update the construct, that your changes may be undone if you use it, so back them up in that scenario.
Also, I include my mount.ak.sh script which make use of a loopfs to accomplish the roughly the same thing, but in a single partition environment (intended as proof of concept).
**There is NO booting into recovery and wiping of the phone for this mod!**
Thanks to JesusFreak for the roms and saurik for the Debian info!
Cheers!
Wow! Nice, Going to try it out. Thanks
is that mean after running data2sd the phone's completely running on sd? and so much faster?
Hi,
To followup on xnycen's question, why would we do this? Is the benefit only in providing more space, or is there also a performance increase (or decrease)?
hate to see the sdcard fail with this change
well...
Yes, after the install you are running complete on sd,
but because of the method used, if you reboot, and take out the sdcard before the boot starts, you will be running as you were before the data2sd aka normal; put the sdcard back in, reboot and you are in data2sd mode again.
This effectively gives you two android run modes: "normal" and data2sd. If the SDCore can not be located the Android will boot in normal mode. You can of course try to keep them sync'd, but if you do the data2sd from a clean slate you can effectively have a "safemode" and if you have an issue with some app, go into this "safemode" and do some investigations or adjustments as the SDCore will mount if you put the sdcard in after the system is in "safemode" but the apps and such will not be loaded until you reboot.
The size expansion is the primary benefit of the construct. As far as speed goes, I haven't checked to see if there are any speed gains in moving /data to the sd... Can someone who's interested check that out and let us know?
Darkstrumn said:
Yes, after the install you are running complete on sd,
but because of the method used, if you reboot, and take out the sdcard before the boot starts, you will be running as you were before the data2sd aka normal; put the sdcard back in, reboot and you are in data2sd mode again.
This effectively gives you two android run modes: "normal" and data2sd. If the SDCore can not be located the Android will boot in normal mode. You can of course try to keep them sync'd, but if you do the data2sd from a clean slate you can effectively have a "safemode" and if you have an issue with some app, go into this "safemode" and do some investigations or adjustments as the SDCore will mount if you put the sdcard in after the system is in "safemode" but the apps and such will not be loaded until you reboot.
The size expansion is the primary benefit of the construct. As far as speed goes, I haven't checked to see if there are any speed gains in moving /data to the sd... Can someone who's interested check that out and let us know?
Click to expand...
Click to collapse
Speed is all I'm interested in If it speeds the device up, why not?
Anyone have anything to report about the speed? I am very interested in this
wow having this "dual boot" seems like an incredible idea... can anyone report on this?
can someone please give a more noob friendly instructions? from what I understand as of now is:
1) boot into recovery and wipe the phone (I'm assuming we can keep whatever ROM we had before)
2) place data2sd.img in root of SDcard (fat32)
3) and this is where I get lost... how exactly do I move the sh file to that location? how do I chmod it? how do I run it? what are the adb commands? thanks!
Hmmnm I thought we weren't doing this because of inheriant security risks?
Not to mention what happens when you mount your fat32 partition....are the apps no longer (as well as your data) available?
NO booting into recovery and wiping of the phone!
Hold up people!
**There is NO booting into recovery and wiping of the phone!**
My bad for not being clear on the wipe instructions!
1) (optional) If you are to wipe it (your choice it is not required), then press menu->settings->SD card & phone storage->scroll to bottom of screen and select "Factory data reset". This will wipe the /data partition only removing all apps and settings. BACKUP YOUR /data dir to sd, First or you will need to down load all your apps again to include paid apps!!
2) place data2sd.img in root of SDcard (fat32)
3) terminal in or adb shell in.
4) cp /sdcard/data2sd.sh to /data/local/bin - to copy the script to your user-space
5) chmod 0750 /data/local/bin/data2sd.sh - to make it executable
6) /data/local/bin/data2sd.sh or data2sd.sh may work to run the script
7) once the install is done it should tell you to reboot. If you had the ddms debugger running, you can observer the log as it is working.
8) done. It may boot a little longer if you clean-slate installed and then restored your apps by copying them back into /data/app and /data/app-private which has the affect of reinstalling everything, and thus the boot will take a while if you have alot of apps like I do. Again you can observe this as the Android boots if you have the debugger running.
thanks a lot man, will give this a shot in a few hours! not at my comp right now
security risks and (u)mounting /sdcard
TheDudeOfLife said:
Hmmnm I thought we weren't doing this because of inheriant security risks?
Not to mention what happens when you mount your fat32 partition....are the apps no longer (as well as your data) available?
Click to expand...
Click to collapse
Not sure why there would be any security issues, the Android is already rooted. If someone can steal the sdcard, they can steal the entire Android, and if the sdcard is left lying about, then yes it can be strolen then too.
The construction of the SDCore assumes all the original permissions, so nothing has access to things it shouldn't save the scripts that use the cache as a backup mount point, but it is given the same permissions as /data, so no worries.
With this construct in place, you can't physically remove the sdcard without first powering off the Android, or rebooting it and removing the sdcard first thing. But while the system is operational, you can mount the sdcard to usb and umount it from usb without issue as long as any mounts to the sdcard are released (loopfs, etc) prior to trying. vold will give 10 tries to umount /sdcard to include attempting to kill the processes with file locks on /sdcard when it tries to umount the volume to attach it to usb.
A a matter of fact, if you observe via teh ddms debugger during boot, the vold service is busy checking the sdcard and mounting it well after the system has already mounted the sdcp2 and begun initializing apps from the sd /data.
So, as long as "sdcard partition2" (sdcp2) remains mounted and all, you can mount the sdcard to the connected Host and back and still have access to your apps and data all you want. I reckon this is how the app2sd and dalvik2sd constructs also perform.
The only thing to really note is that the first partition must be vfat (fat32) and the second either ext2 or ext3 (currently as they support file permissions). vold only cares about the first partition which it expects to be a vfat volume. So as long as p1 is vfat and p2 is posix compliant, we're golden!
The only real question I don't have a good answer for is the speed gains question. My card is a 8GB class6 and things seem fairly responsive. I don't know how much different it would be with a class 4 or 2, or the real speed difference with the built in storage. Honestly it feels a little more responsive, but I haven't really done things that make it feel sluggish.
Oh, I saw the .img and assumed you just mounted the .img from fat32. My bad for not reading all the instructions.
Any problems with apps crashing? I have had a lot of quirky issues in the past with merging the entire partition.
Thanks for the response. I like what you've done here. I'll have to try it out for sure.
TheDudeOfLife said:
Oh, I saw the .img and assumed you just mounted the .img from fat32. My bad for not reading all the instructions.
Any problems with apps crashing? I have had a lot of quirky issues in the past with merging the entire partition.
Thanks for the response. I like what you've done here. I'll have to try it out for sure.
Click to expand...
Click to collapse
No worries; the .img file can be thought of as an install cdrom it is only used the one time during install.
As far as apps crashing, no problems!
During my experimentation building the construct, permission mangling happens if apps are moved out of /data/app, /data/app-private but /data/data and maybe /data/dalvik-cache are not cleaned up prior to copying apps back into their respective app dirs.
What happens is the app dirs are monitored. if you move an apk into the dirs android will install the app. Likewise if you delete an app from those dirs PackageManager will uninstall the app. If /data/data already has the dir for the app, it will use it. if the /data/system/packages.xml and /data/data don't have the same id assigned to that app, you get a permissions\\id conflict; the PackageManager will not manipulate the dir if the id's don't match.
The app /data/local/bin/archiveApps.sh, /data/local/bin/softWIPE.sh and /data/local/bin/restoreApps.sh scripts allow one to backup thier apps to the new /data/app-archive and /data/app-private-archive dirs, clean out /data/data/ /data/dalvik-cache, and restore the apps to their app dirs. As the apps are copied into their dirs, the PackageManager will update /data/system/packages.xml proper and rebuild /data/data and the dalvikVM will build the /dalvik-cahce proper.
Someone made a seemingly nice script (I've not used it yet) called fix_permissions.sh that will parse the /data/system/packages.xml and update the ownership id of the apps /data/data sub dir proper and thus is more scalpel like in operation, but that process doesn't make a backup of the apps; so using both may be the most effective replacing the softWIPE.sh part of the process with the fix_permissions.sh instead.
The only time you should run into issues is if say you have 10 apps installed in teh SDCore /data and 6 in Android /data and then attempt to sync them (because the 6 are different than the 10) by copying\\merging Android /data with SDCore /data the SDCore /data/data /data/dalvik-cache and /data/system/packages.xml will now be mangled.
/data/system/packages.xml will now no longer know about the 10 apps that were installed prior, and on boot PackageManager will "install" them, but /data/data will have dirs inside with now different id's from what was newly assigned them in /data/system/packages.xml, and the 10 apps will now not work correctly but the 6 will as dirs with matching id's were created when they were "installed" new.
To fix, either the softWIPE.sh process outlined above, or the fix_permissions.sh process also mentioned above.
So did anyone try this at all?
Can this be done after doing the apps2sd by marcusmaximus? I tried it but when trying to chmod 0750 /data/local/bin/data2sd.sh it said "No such file or directory" so i tried mkdir /data/local/bin and got "File Exists" so i proceeded with copying data2sd.sh to /data/local/bin again which went without showing any errors and when trying to chmod 0750 /data/local/bin/data2sd.sh again i got the same error so i tried to ls /data/local/bin and just got # what am i doing wrong?
looks interesting! might try this during the weekends ill give an update if i encounter any issues or not
interesting. I'll be looking into this!

[CONCEPT] Single Partition No-Format Apps2SD

So I was using Slax. Great LiveCD/USB linux, extremely customizable, modular, fast, and small, and has the capability of either:
- saving changes to its rootfs onto an AUFS mounted on a non-linux FS (FAT32, NTFS) using posixovl (POSIX Overlay FS) with metadata (permissions, etc.) being held in files
- saving changes to a fixed-size loop mount image.
This got me thinking.
If we could insert all the necessary modules, code, etc. for posixovl into the Android linux, and make a modified a2sd script that takes advantage of posixovl, we could effectively do away with the requirement for crazy partitioning.
It should be simple enough for ROM devs to implement, assuming it's ready and installed:
1. Create folder on main partition if it doesn't exist, something like /sdcard/system/[app, app-private, dalvik-cache, app_s]
2. In the init scripts, before the a2sd stuff, mount /sdcard/system with posixovl on /system/sd
3. Run a2sd as normal, it should automatically just work.
I'll hopefully test this once I get my phone to a stable development/testing stage, and I don't need to make phone calls for a while. Anyone else is welcome to try to implement this idea.
My current test environment:
- HTC Dream (T-mo G1) with the deadly SPL of doom
- Cyanogen Experimental, latest build
- Amon_RA's modded recovery
- Wipe /data, move all existing apps to backup, remove a2sd partition, Backup for Root Users to restore some settings and data
Anyone with ideas or improvements, please let me know.
To be tested:
- Feasibility (can it work?)
- Functionality (does it work?)
- Portability (Can it work on other ROMs and devices like Hero, Pulse, Blur etc.? If so, will likely be moved to XDA's new Android board)
- Stability (Will everything Force Close on boot? Does it run fast enough? Does anything get corrupted over time?)
Links:
- http://sourceforge.net/projects/posixovl - Sourceforge page for posixovl
In desktop linux you can create a file with the touch command, and mount the file to a mountpoint after formatting it to ext4 for example.
Maybe this is the easier way?
I have done this about 5 years ago, but I will try it today and report if it worked.
edit: ok done already:
1. create a file of the desired size, eg: dd if=/dev/zero of=filename bs=filesize count=1
2. use mke2fs to format the file
3. create a mountpoint and mount the file
thats all. Now I have a 128MB file on my PC, mountable and usable like a partition.
Archont said:
In desktop linux you can create a file with the touch command, and mount the file to a mountpoint after formatting it to ext4 for example.
Maybe this is the easier way?
I have done this about 5 years ago, but I will try it today and report if it worked.
Click to expand...
Click to collapse
As far as I know, you can do that on the mobile Android, too, and that does work in theory. This technique involves mounting a loop filesystem, and it too will allow one-partition apps2sd, but it's less flexible, and I would think slower, than the overlay method.
For a 512MB apps image:
Create empty 512MB file
# dd if=/dev/zero of=/sdcard/apps.img bs=1024k count=512
Format it to Ext2
# mke2fs -L Apps2SD /sdcard/apps.img
Unmount existing a2sd
# umount /system/sd
mount new a2sd image
# mount -t ext2 -o loop /sdcard/apps.img /system/sd
Make the usual directories, and a mountpoint for the old a2sd partition
# mkdir /system/sd/app; mkdir /system/sd/app-private; mkdir /system/sd/dalvik-cache; mkdir /system/sd/apps-tmp
Mount the old a2sd partition
# mount -t ext2 /dev/mmcblk0p2 /system/sd/apps-tmp/
Move all files from the old partition to the image file
# mv /system/sd/apps-tmp/* /system/sd/
Unmount and remove the mountpoint, we don't need it anymore
# umount /system/sd/apps-tmp
# rmdir /system/sd/apps-tmp
Finally, you add the following line to the init script where the a2sd auto mount happens, and comment out the old line.
Code:
[...]
mount -t ext2 -o loop /sdcard/apps.img /system/sd
#mount -t ext2 /dev/mmcblk0p2 /system/sd/
[...]
This should do what you described, in theory. I can't say whether it will work or not. I can't tell whether it will or won't screw up your phone, I can't be held responsible if you screw something up or overlook the details. Either of us might have made a typo somewhere; apply common sense before doing anything.
This sounds great! I think this would also be usefull for someone like me, who has a sd card that doesn't want to be partitioned anymore (cross-linked files??). Only thing possible is fat32 or ntfs.
Am I correct with my assumption?
This sounds a lot harder and more complicated then partioning. Your also talking about a lot of work needing to be done just so people can avoid doing a simple thing like partioning a sd card. I would say it would be very difficult alone to get the os to run a virtual mounting service especially since that will take up resources and slow down the phone. There is a reason they only use this technique on live cds is it works but its slow. most of the computers they are running on have 1gig of ram and 2ghz cpu's. i really dont think the g1 can push this.
I do not think that this is great, it definitely is slower than a ext4 partition on a good class 6 microSD card. And it is more vulnerable to data loss since 2 different filesystems including a 20 year old non-journaling fs at the base of this construct are involved.
Another problem that came to my mind: when you mount your SD card as external USB device to a PC, the file containing your apps will no longer be accessible, or Android will make using the phone as external data storage impossible.
Interesting.
There is, however, a major problem: What happens when you unmount the fat partition on the phone in order to connect with a computer using UMS? Answer: everything on the phone will crash and burn since the apps filesystem will suddenly disappear = BAD.
posixovl is a nice find though...
Note that aufs, loopmount linux filesystems, etc., wouldn't be needed with this since posixovl appears to be vfat with posix extensions, so you should be able to just use posixovl directly on the sdcard.
There are several problems with that though... i.e. how reliable is posixovl regarding users tampering with it?
In any case, a prerequisite for use of it would be certain other changes being planned...
You might want to contribute to this thread:
http://forum.xda-developers.com/showthread.php?t=577941
(note: the thread links to a thread at android-platform, the one here has, as expected, gone off on a tangent... just ignore the junk.)
TylTru said:
So I was using Slax. Great LiveCD/USB linux, extremely customizable, modular, fast, and small, and has the capability of either:
- saving changes to its rootfs onto an AUFS mounted on a non-linux FS (FAT32, NTFS) using posixovl (POSIX Overlay FS) with metadata (permissions, etc.) being held in files
- saving changes to a fixed-size loop mount image.
This got me thinking.
If we could insert all the necessary modules, code, etc. for posixovl into the Android linux, and make a modified a2sd script that takes advantage of posixovl, we could effectively do away with the requirement for crazy partitioning.
It should be simple enough for ROM devs to implement, assuming it's ready and installed:
1. Create folder on main partition if it doesn't exist, something like /sdcard/system/[app, app-private, dalvik-cache, app_s]
2. In the init scripts, before the a2sd stuff, mount /sdcard/system with posixovl on /system/sd
3. Run a2sd as normal, it should automatically just work.
I'll hopefully test this once I get my phone to a stable development/testing stage, and I don't need to make phone calls for a while. Anyone else is welcome to try to implement this idea.
My current test environment:
- HTC Dream (T-mo G1) with the deadly SPL of doom
- Cyanogen Experimental, latest build
- Amon_RA's modded recovery
- Wipe /data, move all existing apps to backup, remove a2sd partition, Backup for Root Users to restore some settings and data
Anyone with ideas or improvements, please let me know.
To be tested:
- Feasibility (can it work?)
- Functionality (does it work?)
- Portability (Can it work on other ROMs and devices like Hero, Pulse, Blur etc.? If so, will likely be moved to XDA's new Android board)
- Stability (Will everything Force Close on boot? Does it run fast enough? Does anything get corrupted over time?)
Links:
- http://sourceforge.net/projects/posixovl - Sourceforge page for posixovl
Click to expand...
Click to collapse
lbcoder said:
Interesting.
There is, however, a major problem: What happens when you unmount the fat partition on the phone in order to connect with a computer using UMS? Answer: everything on the phone will crash and burn since the apps filesystem will suddenly disappear = BAD.
Click to expand...
Click to collapse
I kinda overlooked that point. Oops.
Though this same problem does exist on regular apps2sd when you remove the card without dismounting it, killing all apps and their processes, and freezing Dalvik's method of autostarting some apps.
I do tend to swap cards every now and then, but only after a reboot. Dalvik re-enumerates and caches dex, which makes for a slow boot, but it seems to just work in most cases that the apk install doesn't drop the app's functional payload (helper Linux/shell utils, libraries, NDK .so's) in /data/data (like some emulators, the Android Scripting Environment)
lbcoder said:
There are several problems with that though... i.e. how reliable is posixovl regarding users tampering with it?
Click to expand...
Click to collapse
As far as I know, the metadata files are marked as hidden and system files, and begin with a '.'. And I haven't tried this, but I think modifying the actual files under Windows has no negative effects, but moving, deleting, or copying files would likely be a no-no.
Also, I don't think there's a 'fsck' for posixovl, meaning that if any metadata files were screwed with the wrong way, the entire overlay FS would be trashed.
lbcoder said:
In any case, a prerequisite for use of it would be certain other changes being planned...
You might want to contribute to this thread:
http://forum.xda-developers.com/showthread.php?t=577941
(note: the thread links to a thread at android-platform, the one here has, as expected, gone off on a tangent... just ignore the junk.)
Click to expand...
Click to collapse
I checked that out. It was actually a small inspiration for what I was thinking of.
In any case, Android's package management system needs an overhaul. The package storage needs to be de-Linuxified, as all it is is a bunch of .apk files and .dex/.odex files, the UIDs of apps are in the AndroidManifest.xml, right?
In a somewhat unrelated note, app data needs to be moved to a specified folder structure on the sdcard. My card is full of folders in the root directory with random names.
If I'm understanding you correctly, you're talking about storing an image file on the normal SD card partition(which has to be FAT32 as far as I've seen) and then mounting it, correct? This idea has been talked about at length before on at least 3 separate occasions(2 of which were on this very forum) and found to be a bad idea due primarily to massive security risks since FAT32 has no permissions.
Also, I believe cyanogen ended up dumping unionfs/aufs due to rampant memory issues.
If you are talking about mounting an image from the FAT32 partition, please don't endorse this. We don't want to be throwing in security bugs into android, especially ones such as this which can't be plugged up.
As a modification to what I said: If you're suggesting doing this(or something similar) on a separate filesystem, after that project to change the AOSP to support one with permissions is finished, then I'm in full support.
If you want to go for a single partition on the sd card, why don't you just make the entire card use ext4? Your linux desktop reads it anyway, it uses journaling and so on, I guess it would be faster compared to fat32 and it is definitely safer to use.
And i guess it is not too complicated to mount this partition and use it for pictures, music and so on.
I have not tried this (yet) and I go to bed in 20 minutes, but maybe I will start testing something in that direction tomorrow.
[email protected] said:
If I'm understanding you correctly, you're talking about storing an image file on the normal SD card partition(which has to be FAT32 as far as I've seen) and then mounting it, correct? This idea has been talked about at length before on at least 3 separate occasions(2 of which were on this very forum) and found to be a bad idea due primarily to massive security risks since FAT32 has no permissions.
Also, I believe cyanogen ended up dumping unionfs/aufs due to rampant memory issues.
If you are talking about mounting an image from the FAT32 partition, please don't endorse this. We don't want to be throwing in security bugs into android, especially ones such as this which can't be plugged up.
As a modification to what I said: If you're suggesting doing this(or something similar) on a separate filesystem, after that project to change the AOSP to support one with permissions is finished, then I'm in full support.
Click to expand...
Click to collapse
UNIX permissions don't do anything in the way of "security" unless you have no access to the actual storage device from another computer (as is the case with the unrooted Dream's internal memory), or unless encryption is used. The posixovl driver OVERLAYS Unix permissions over Fat32 filesystems. But even still, with Unix permissions, nothing's stopping someone else from mounting the Ext2 partition and using chown and chmod.
And the image file on the SD card's Fat32 partition is a complete Ext2 partition complete with Permissions. Nothing is lost.
Archont said:
If you want to go for a single partition on the sd card, why don't you just make the entire card use ext4? Your linux desktop reads it anyway, it uses journaling and so on, I guess it would be faster compared to fat32 and it is definitely safer to use.
And i guess it is not too complicated to mount this partition and use it for pictures, music and so on.
I have not tried this (yet) and I go to bed in 20 minutes, but maybe I will start testing something in that direction tomorrow.
Click to expand...
Click to collapse
We'd just have to find the part in the Android that mounts /sdcard/, and change 'vfat' to 'ext2'. The only reason I wouldn't do this, is because it would immediately make it incompatible with Windows and Mac's default FS drivers. As far as I know, the only FS's that are supported universally within Linux, Mac, and Windows, are FAT and NTFS. And NTFS can be made to have crude support for permissions through security descriptors. Although, the Dream SPL, the Recovery images, and most of Android only uses FAT32.
This is discussed in android-platform Group :
http://groups.google.com/group/andr...read/thread/bf0709c157451cd9/f6aee1830c84620f
The goal is to be able to integrate this in android.
And not having to partition the SDCard is one of the requirements so far...
Unix permissions are not stored using fat or vfat, and ntfs is not really supported in desktop linux and i guess it cannot be used in android linux.
I would not use windows anyway so this is no problem to me, and there are drivers around to mount ext systems in windows. As Mac OS is based on unix there will be a solution for this too.
Access usind adb push and pull, via ftp and so on is not touched by using ext4 on the entire sd card I guess.
And if you don't go the easy way using gparted on a live cd or usb device to create 2 partitions, you will have to live with some disadvantages anyway.
Finally I want to say that my ideas are far from being perfect or usable at all, I see this thread as a kind of brainstorming.
im not as linux or android savvy as probably any of you but before the current method of creating a swap partition became the "standard", people used a swap file on the sdcard and linked that. seems similar to what you are suggesting here.
ofcourse when mounting the fat partition elsewhere (ums in windows for example) that swap file could no longer be used within android. i dont see a way to get passed the same issue, but worse here, due to android not having crucial apps when the fat partition is mounted.
then again, i am pretty much over my head in this conversation and could be over looking something...
I'm kind of fascinated by the FUSE + posixovl method of doing this. In the long run I have a feeling that it's going to perform like ****, but I think it's worth testing.
I managed to get both libfuse and mount.posixovl built and running on Android.
posix-overlay(/sdcard/fuse) on /sdcard/fuse type fuse.posixovl (rw,nosuid,user_id=0,group_id=0,default_permissions)
Giving this a little testing now, it definitely works.
Code:
/sdcard/fuse # ls -l
drwxr-xr-x 2 1000 1000 4096 Nov 5 17:17 test
TylTru said:
UNIX permissions don't do anything in the way of "security" unless you have no access to the actual storage device from another computer (as is the case with the unrooted Dream's internal memory), or unless encryption is used. The posixovl driver OVERLAYS Unix permissions over Fat32 filesystems. But even still, with Unix permissions, nothing's stopping someone else from mounting the Ext2 partition and using chown and chmod.
And the image file on the SD card's Fat32 partition is a complete Ext2 partition complete with Permissions. Nothing is lost.
We'd just have to find the part in the Android that mounts /sdcard/, and change 'vfat' to 'ext2'. The only reason I wouldn't do this, is because it would immediately make it incompatible with Windows and Mac's default FS drivers. As far as I know, the only FS's that are supported universally within Linux, Mac, and Windows, are FAT and NTFS. And NTFS can be made to have crude support for permissions through security descriptors. Although, the Dream SPL, the Recovery images, and most of Android only uses FAT32.
Click to expand...
Click to collapse
Ya, I meant more from the standpoint of a rogue app. Since FAT32 has no permissions, what would prevent such an app from modifying the stored image file to, say, change a trusted app with superuser permissions to some new code of its own making to, for example, watch for credit card numbers and send them back to the person who made the original rogue app? I'm always hesitant with any ideas that suggest storing an image file on the sdcard for appstosd for this reason.
Forget it, it's useless.
An overlay filesystem prevents you from enabling USB storage.
If you want to play around with FUSE on Android, here's a repository for my port of libfuse..
http://github.com/cyanogen/android_external_fuse
Hi,
I have an idea. I used symbian S60 of Nokia, Symbian can install app to sdcard. I see that when I mount sdcard to PC, my phone immediately hold all activations of all applications on my phone. And they have a PC sync software that help us access sdcard but not mount sdcard (like that we copy file from computer to sdcard via debug mode on android).
I think we should find out how symbian can do it and we will use their way .
I'm not a developer, I'm just an user.
I talked to a few people about this, and some deep kernel voodoo is going to be needed for this to really happen without partitioning.
Another idea is to forge ahead with this, and ditch the "unmount fs for usb storage" and use RNDIS + Samba or something like that instead to access files on SD. I kind of like this idea.

[Q] Replace Internal Data Partition for External SD

Let me start with: I know that there have been many posts on this, but before you get mad, I was unable to find an answer to what I specifically want to do.
For reference: I am a software developer and sysadmin with a decent amount of Linux experience, but not a lot of android specific experience.
Now that the introduction is out of the way:
What I would like to do is completely remove the "USERDATA" partition (the "Internal SD card"), grow the "SYSTEM" partition to fill that space, and then mount my SD Card (external) as the SD Card that the system sees.
I'm currently on Cyanogenmod 10.1 but want to upgrade to 11 soon.
The reason I want to do this is because:
I have all if my apps that I can set to install to SD Card
Both "internal" partitions are full (only about 200MB is available for pictures/etc. and I can no longer update apps)
Camera (and pretty much everything else as well) stores to the Internal SD card by default
If the system partition was 1.1+1.4=2.5GB and all of my apps were "installed" to a real SD card, it would be a lot more comfortable.
So, here's what I am thinking *might* work (maybe not in the right order, though?):
Point the fstab entry for the internal SD card to the external SD card
I have the PIT file. I will delete the "USERDATA " and grow "SYSTEM" to fill the space
When I write it out in steps, it seems pretty simple...
My concerns:
Will a ROM update (to CM11) re-partition back to the old way (and, in the process, break a bunch of stuff)?
I don't ever plan to go back to stock android or change to another ROM (other than upgrades).
Thanks for reading this long post and for any insight you may be able to provide.
--mobrien118
It's a wonderful idea if it works.
Sent from my SAMSUNG-SGH-T769 using xda app-developers app
Modifying partitions is a bit dangerous.
But I have to ask you why do you need another GB of /system storage?
There was a line you can put in the build.prop that flips your ext. SD with the internal one on cm10 I believe.
This'd interest me if I could get rid of usbdisk and sdcard0 merged.
It would need the phone to be repartitioned though, causing issues with the backups and ROMs.
You may even have to compile cm from source.
Its a lot of trouble
Sent from my SAMSUNG-SGH-T769 using Tapatalk
I just did so on S4 Mini with cm-11 Android 4.4.
First I was thinking of using symlinks and/or bind mounts to redirect to the the external sdcard, but that's a bit of a hassle because
1) Since 4.2: both emulated and external storage is mounted with a fuse layer on top not supporting symlinks
2) Since 4.4: no more global write access on external storage
So moving data was the simplest solution. Besides providing (much) more space my sdcard is also around 20% faster in sequential writes: 8.5 MB/s internal vs 10.5 MB/s external. Is it really 2014?
I haven't yet decided what to do with the original data partition, so for the moment I left it unused. Hence I haven't touched the internal partition table.
Quick summary
partition sdcard (gdisk)
I recommend using GPT, this lets you work with partition names rather than numbers. For the sake of still having an "official" external sdcard I made two partitions. Keep in mind that it's usually the first partition which gets automatically mounted as external sdcard. So I made the 2nd partition the new home for data. This partition however has to be manually specified in the ramdisks fstab which involves flashing the boot partition.
format the new partitions (mkfs.ext4)
copy the original /data directory tree to the new data partition
extract initrd from boot.img (abootimg)
extract files from initrd (gunzip & cpio)
replace the /data entry in fstab pointing at your new data partition
re-pack initrd and boot.img (gzip, cpio & abootimg)
flash boot.img onto the boot partition (dd)
If you use recovery, you also have to edit it's fstab (analog to boot.img mentioned above)
done
Alternatively has anyone tried an init.d script? I see those scripts get executed before the mounting of data & sdcard
Meanwhile the original userdata partition got replaced by 3 new partitions: system2, cache2 & userdata2 which are now used for a dual boot ROM.
I've only changed GPT, not PIT. ROMs and Recovery don't use PIT, so as long as Heimdall/Odin isn't involved it should not cause any issues.
Hey guys,
So after read all that, I am also vry interested in what the OP has suggested. I get that the pit doesn't need to be affected, but as the OP asked, when flashing a new rom or updating an existing, would the partition be reformatted back to the way android handles it, ie; back to the system and data seperate and the sdcard not being used as the internal partition?
I am no developer and only have minimal knowledge in linux and android programing, but I am a quick study and any guide to help me sort this would be greatly appreciated.
Also I am about to get a second S4 mini specifcally for doing things like this so if I brick I don't care?
My next question is could it be possible to code the PIT file to do this for you so that you can just flash that through odin, but again would flashing roms affect this.
Cheers,
Sora.
aguaz said:
I just did so on S4 Mini with cm-11 Android 4.4.
First I was thinking of using symlinks and/or bind mounts to redirect to the the external sdcard, but that's a bit of a hassle because
1) Since 4.2: both emulated and external storage is mounted with a fuse layer on top not supporting symlinks
2) Since 4.4: no more global write access on external storage
So moving data was the simplest solution. Besides providing (much) more space my sdcard is also around 20% faster in sequential writes: 8.5 MB/s internal vs 10.5 MB/s external. Is it really 2014?
I haven't yet decided what to do with the original data partition, so for the moment I left it unused. Hence I haven't touched the internal partition table.
Quick summary
partition sdcard (gdisk)
I recommend using GPT, this lets you work with partition names rather than numbers. For the sake of still having an "official" external sdcard I made two partitions. Keep in mind that it's usually the first partition which gets automatically mounted as external sdcard. So I made the 2nd partition the new home for data. This partition however has to be manually specified in the ramdisks fstab which involves flashing the boot partition.
format the new partitions (mkfs.ext4)
copy the original /data directory tree to the new data partition
extract initrd from boot.img (abootimg)
extract files from initrd (gunzip & cpio)
replace the /data entry in fstab pointing at your new data partition
re-pack initrd and boot.img (gzip, cpio & abootimg)
flash boot.img onto the boot partition (dd)
If you use recovery, you also have to edit it's fstab (analog to boot.img mentioned above)
done
Alternatively has anyone tried an init.d script? I see those scripts get executed before the mounting of data & sdcard
Click to expand...
Click to collapse
I just managed to replace my internal sd with the external sd following your ruff guide. thank you very much! At first I struggled a bit getting it to work, because I had encrypted my data partition before -.- this seems to change something in the fstab / mounting / boot-up process, I couldn't get my S4 mini to boot with just changing the fstab.qcom in boot.img. With my recovery (TWRP) it worked from the start editing recovery.img's fstab.twrp /data mount point.
After decrypting(formatting) /data and re-editing fstab.qcom in boot.img it finally works I'm so happy! Enjoying a lot of space on my sdcard now!
usefull threads / information I learnt from:
Partition structure of S4 Mini
Encryption of ExtSD & some fstab information
Editing initrd
abootimg ReadMe
(Links last tried 28.05.2015)

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