[Q] Mount loop device on rooted android devices - General Questions and Answers

I have been trying to mount an image file on my device with no success. The image was created on a linux PC with dd and formated with a DOS partition table and a single ext2 partition. All three devices I have tried this on do not find the partition (should be /dev/block/loop5p1 according to fdisk on the android device).
Code:
busybox losetup /dev/block/loop5 /sdcard/m.img
busybox mount -t ext2 /dev/block/loop5 /sdcard/mnt
This returns invalid argument, probably because it is not a partition.
Code:
busybox losetup /dev/block/loop5 /sdcard/m.img
busybox mount -t ext2 /dev/block/loop5p1
This returns device not found because android will not find the partitions.
Is there a way to make this image mount or could I create a file system on the image without a partition table (mkfs.ext2 /dev/block/loop5) and try to mount it?

I have got the image to mount on one device by making a filesystem on the image without a partition table
Code:
mkfs.ext3 /dev/loop0
and mounted it successfully on the device by using
Code:
busybox mount /dev/block/loop0 /sdcard/mnt/
however on one of the other devices the same thing results in only the cd and ls commands being able to see the mounted files (not chroot or other android apps).
Is there anything I'm doing wrong or is it just the device?

Related

using the internal memory as a virtual sdcard

I managed to break my micro sd card in half today and I wasn't able to pickup a class 10 or 6 replacement locally so I thought I could use some of the 6gb of internal memory as a virtual filesystem to get me out of trouble.
So, after quickly looking at the android docs and the supported busybox commands I created a 2gb sdcard.img in /data and mounted to /sdcard. I copied some files to it with astro filemanager and fired up raging thunder 2 and it went ahead and downloaded the game data to /sdcard/ and worked correctly.
But, a few apps won't recognise it as an sdcard (Motorola SD card and phone storage settings applet) as well as things like PlayPro (states I have no sdcard present). I thought perhaps I could modify the /etc/vold.fstab file to auto mount the sdcard.img I created using vi but I'm a bit clueless as to what I should change on the dev_mount /sdcard line to get it automounted at boot and hopefully fool the rest of the apps into thinking it is a physical sdcard.
Can anyone possibly point me in the right direction? Not sure how to invoke cmd mode in vi using the milestone qwerty either but I'll keep digging.
What I did (roughly), maybe I'm going about it wrong but any advice would be appreciated.
1. rooted device
2. installed the free terminal app from the market
3. fired up the terminal shell
4. su
5. dd if/dev/zero of=/data/sdcard.img bs=1024 count=1 seek=2000000
6. busybox mkfs.vfat /data/sdcard.img (didn't seem to support -F 32)
7. busybox mount -o loop /data/sdcard.img /sdcard/
+ 1 for this, it would be great to can use internal storage for user data
Why do you let this nice post die.. so "flibbulator" found anything more out?.. I'd like to know more.. like if you got it to work with Music Players and Video players??
Try to mount /data/sdcard.img to /mnt/sdcard (/sdcard is a link to /mnt/sdcard)
or try "export EXTERNAL_STORAGE /sdcard"
I made in a different way: created a 4GB storage.img in /data and mounted it in /sdcard/storage, so internal storage is finally usable for user data
the problem was to set mount point on boot, I can't find a way to execute a script on boot (you can't permanently modify init.rc)
flibbulator said:
What I did (roughly), maybe I'm going about it wrong but any advice would be appreciated.
1. rooted device
2. installed the free terminal app from the market
3. fired up the terminal shell
4. su
5. dd if/dev/zero of=/data/sdcard.img bs=1024 count=1 seek=2000000
6. busybox mkfs.vfat /data/sdcard.img (didn't seem to support -F 32)
7. busybox mount -o loop /data/sdcard.img /sdcard/
Click to expand...
Click to collapse
I have actually tried this on my Droid2Global, and I get the error "unknown operand if/dev/zero" I feel like I am missing the point or do not fully understanding how to use the "dd" command?
the correct syntax is:
dd if=/dev/zero of=/data/sdcard.img bs=1024 count=4194340
4194340 --> 4GB
patton82 said:
the correct syntax is:
dd if=/dev/zero of=/data/sdcard.img bs=1024 count=4194340
4194340 --> 4GB
Click to expand...
Click to collapse
Thank you bro.
Quick question I keep getting these errors. I do have a folder in "/" named "sdcard-int"
Better Terminal Emulator Pro
/ # busybox mount -o loop /data/sdcard.img /sdcard-int/
mount: can't setup loop device: No such file or directory
/ # busybox mount -o /data/sdcard.img /sdcard-int
mount: can't read /etc/fstab: No such file or directory
/ #
Sent from my DROID2 GLOBAL using Tapatalk
you can't place anything in root folder, /sdcard is a link to /mnt/sdcard and is created by init.rc (you can't edit init.rc, it's provided by boot.img, so need to extract from boot.img and repack)
I made in this way but I have to manually execute a script or a command from terminal after every boot to mount storage.img
mkdir /sdcard/storage
su
dd if=/dev/zero of=/data/storage.img bs=1024 count=4194340
busybox mkfs.vfat /data.storage.img
mount -o loop -t vfat /data/storage.img /sdcard/storage
Will be lost anything after reboot when use this storage?
Sent from my MotoA953 using XDA App
all the stuff in img file will not be lost, as long as you put it in /data/
on the contrary the mount point must be restored after reboot
patton82 said:
you can't place anything in root folder, /sdcard is a link to /mnt/sdcard and is created by init.rc (you can't edit init.rc, it's provided by boot.img, so need to extract from boot.img and repack)
I made in this way but I have to manually execute a script or a command from terminal after every boot to mount storage.img
mkdir /sdcard/storage
su
dd if=/dev/zero of=/data/storage.img bs=1024 count=4194340
busybox mkfs.vfat /data.storage.img
mount -o loop -t vfat /data/storage.img /sdcard/storage
Click to expand...
Click to collapse
Thank you, I will use the Thank you button when I login via PC.
I still get the same error, I know that I'm doing something incorrectly or maybe I don't understand "mount" comment correctly?
/ $ su
/ # mkdir /sdcard/storage
/ # dd if=/dev/zero of=/data/storage.img bs=1024 count=41943404194340+0 recordsn
4194340+0 records out
4295004160 bytes (4.0GB) copied, 339.823883 seconds, 12.1MB/s
/ # busybox mkfs.vfat /data/storage.img
/ # mount -o loop -t vfat /data/storage.img /sdcard/storage
mount: can't setup loop device: No such file or directory
/ #
I am using my sdcard also, I'm not too sure if that makes any difference?
Sent from my DROID2 GLOBAL using Tapatalk
Better terminal pro uses BASH shell, I presume
try to switch to android shell, in preferences
or to use terminal emulator (free) from market
Okay, I tried Android Terminal Emulator, and this is a new error.
export PATH=/data/local/bin:$PATH
$ $ su
# mount -o loop -t vfat /data/storage.img /sdcard/storage
ioctl LOOP_SET_FD failed: Device or resource busy
#
Not too sure where to go now. I thank you again for all your help, and time.
Sent from my DROID2 GLOBAL using Tapatalk
resource busy, you have to reboot the phone
I use Gscript lite, add a script with the string
mount -o loop -t vfat /data/storage.img /sdcard/storage
and create a shortcut to homescreen, so when I reboot, I can mount the img file in one click
Cool mod for my ROM. Could I take it??
sure, they are simple shell commands
the best would be to do what happen with Samsung Galaxy S: internal storage mounted as sdcard and physical sdcard mounted in a folder /sdcard/sd
storage.img is 3-4 times faster than my peak 8GB class 6
There is an application "Autostart" in the market, which can automatially execute a script with root after boot up.
I up because I'm now also interested in making profit of the huge internal storage. I'd like to put my wikipedia data from wikidroyd to the internal storage. Hopefully I'm skilled enough to follow the given steps...I doubt that though
fKngFtd said:
Okay, I tried Android Terminal Emulator, and this is a new error.
export PATH=/data/local/bin:$PATH
$ $ su
# mount -o loop -t vfat /data/storage.img /sdcard/storage
ioctl LOOP_SET_FD failed: Device or resource busy
#
Not too sure where to go now. I thank you again for all your help, and time.
Click to expand...
Click to collapse
Guys, I need your help! I have exactly. The same problem:
Every time I try to mount my storage.img I get
Ioctl LOOP_SET_FD failed: Device or resource busy.
I rebooted several times and also tried to mount smaller images (first I tried 3gb then I tried 1mb).
Any solution?
Edit: I solved it myself. I always forgot to punch in busybox before the command. Now it worked for me!!
I do have a question now. With help of Gscript I made a shortcut to mount the storage.img to my sdcard. But my pc wont recognise the sdcard as long as the image is mounted. What is the command to unmount the partition so I wouldnt have to reboot my phone before connecting it to the pc...?
Any help is much appreciated! Thx
(Something like busybox unmount -o loop -t vfat...?)
Sent from my MotoA953 using XDA App

Sometimes impossible to mount system partition ?

How to explain that it is impossible to mount the system partition in recovery ? Should I format my sd card to correct that ?
the /system/ files do not reside in your sd card. They are stored in your phone. Are able to boot up your phone at all? If so you can mount it via a terminal app. You might also need busybox installed. At the terminal type the following
$ su
# mount -o rw,remount -t yaffs2 /dev/block/mtdblock1 /system

[Question] Converting MTD Partition(s): yaffs2 -> ext2/3/4

hi @all,
is there a way to convert a mtd partition to another filesystem?
i've tryed the following procedure:
1.) boot to recovery
2.) login to system via adb (adb shell)
3.) mke2fs -m 5 -b 4096 /dev/block/mtdblock1
at point 3, it gives errors and nothing is happen.
now, i've tryed to flash a ext3 filesystem on this partition via
flash_image system system.ex3.img (found a explanation on how to create a ex3 system.img), but after mounting the /dev/block/mtdblock1 on /system it shows still device as "yaffs2".
would be nice, if someone can explain me if it's definitvly not possible to convert
mtd partitions or tell me a short tip what can i test
ThX
Andy
An anything known about this in the last year BUMP

Clean Your File Systems!

Ok, lately we have had a rash of errors and undesired performance. In my opinion, this is unacceptable... So I am trying to fix it. Now, I can't fix every issue, but boy can I sure help most of them...lol
So let's get started. We will call this:
The File System Cleaner
Linux has a few tools for us to see if we have a "Dirty" or "Clean" filesystem.
They are tune2fs, e2fsck, and fsck_msdos.
Now, you can't use all of them for every file system or partition (we will refer to them all as partitions from here on out). Each one works on certain filesystems. For example, e2fsck works on ext type partitions where fsck_msdos works on vfat type partitions, and tune2fs only works on large partitions.
While tune2fs is a tool that gives detailed information about a partition, it can still give us an idea on where we stand on those larger partitions as well as change certain options/features on that partition such as journaling, mount point, mount as rw or ro, etc. But the biggest thing we are going to focus on is 1 line:
Code:
Filesystem state
If you run tune2fs and the filesystem state is anything other than clean, you have some sort of gremlin floating about it and it needs to be fixed. Now what about those partitions in which we get these errors:
t
Code:
tune2fs 1.41.11 (14-Mar-2010)
tune2fs: Attempt to read block from filesystem resulted in short read while trying to open /dev/block/mmcblk0p4
Couldn't find valid filesystem superblock.
1|[email protected]:/ # tune2fs -l /dev/block/mmcblk0p28
tune2fs 1.41.11 (14-Mar-2010)
tune2fs: Bad magic number in super-block while trying to open /dev/block/mmcblk0p28
Couldn't find valid filesystem superblock
It doesn't mean that they are corrupt. It means they are either not in a format that tune2fs can read or they are not a large partition.
So for those partitions that are not compatible with tune2fs, we can use fsck.
The fsck works much like scan disk and defrag in windows. It scans the partition for several different things like bad blocks, missing/corrupt information, etc. Although you can run tune2fs on any large partition whether it is mounted or not, you DO NOT want to fsck ANY partition that is mounted or it WILL result in TOTAL data LOSS! You have been warn!
Keep in mind all this information is at your own risk, but know that I have been using this for quite some time and it hasn't failed me yet. But then again, I follow my instructions to a TEE, as you should as well...
So, here's how we use all this.
First make sure you have adb installed on your computer
To be safe, boot into recovery, plug your phone into your computer and start adb shell
Now type:
Code:
mount /system
cp /system/bin/tune2fs /tmp
cp /system/bin/e2fsck /tmp
cp /system/bin/fsck_msdos /tmp
chmod -R 777 /tmp
cd tmp
Now that our tools are set, we can now begin cleaning house.
First and most important, make sure you umount ALL partitions.
I personally unmount them manually via mounts and storage in CWM.
In terminal (with adb running) type:
Code:
./tune2fs -l <partition>
./e2fsck <partition>
./fsck_msdos <partition>
**NOTE**If you have an error "/sbin/sh: <command>: not found" when executing one of these commands simply mount /system and copy to tmp, and chmod 777 again.**
For more information on the commands, run <command> -h. here you will see additional options for that command.
Now, I didn't break down which partitions work with tune2fs, but /system, /data, and /cache can be scanned with tune2fs.
However, I did break as to what partitions need which fsck command to be cleaned.
Code:
e2fsck
|mount point| |Filesystem type|
/dev/block/mmcblk0p21 /efs
/dev/block/mmcblk0p24 /system
/dev/block/mmcblk0p25 /data
/dev/block/mmcblk0p26 /cache
/dev/block/mmcblk0p27 /tombstones
/dev/block/mmcblk1p2 unknown
Code:
fsck_msdos
|mount point| |Filesystem type|
/dev/block/mmcblk0p4 fsinfo
/dev/block/mmcblk0p13 /system/etc/firmware/misc
/dev/block/mmcblk0p17 /system/etc/firmware/misc_mdm
/dev/block/mmcblk0p28 emmc
/dev/block/mmcblk1p1 /sdcard
Example:
Code:
/tmp # e2fsck /dev/block/mmcblk0p24
e2fsck 1.41.12 (17-May-2010)
/dev/block/mmcblk0p24: clean, 4220/38320 files, 93625/153088 blocks
This should resolve many of your laggy performance and random reboot issues. As well as the issue of freezes after a reboot.
If you are a flash addict, tuning your partitions between flashes my be a GREAT idea...
If you do not have those binaries in your ROM, let me know and I will upload them here...
Now, there is a little more destructive way to clean a partition, and that is to reformat it. Most of us format /system /cache and dalvik in CWM before flashing, but sometimes that isn't enough. All CWM does is erase the files/folders contained in one of those partitions.
Here's how we do a complete reformat:
Reboot to recovery, plug phone in and start adb shell
Type:
Code:
mount /system
cp /system/bin/make_ext4fs /tmp
chmod 777 /tmp/make_ext4fs
mount <system, data or cache partition>
./make_ext4fs <partition>
This only works with ext4 partitions, so use it ONLY on these:
Code:
/dev/block/mmcblk0p24 /system
/dev/block/mmcblk0p25 /data
/dev/block/mmcblk0p26 /cache
I know there are other ext partitions, like tombstone and efs, but DO NOT use this command on them. You may BRICK or damage your device. I will say this again, ONLY DO THIS on data, cache, system!
**NOTE** If you format system partition, you WILL have to flash your ROM and Gapps again...
I have not had windows on this pc for over 2 years now and I think ADB is MS only right? I do flash a lot but I normally run ultimate kernel cleaning script and plus run the wipes a couple times myself and sumtimes format cache partitons before I install a new rom.... I like to make sure I do most I can to clean before I flash...and I always run the LZ kernel Cause its AWESOME!! but I guess my question is how can I look to see if my partitons need to be cleaned.. on AOKP with LZ kernel at moment and it is smooth fast and no bugs or reboots. is there a way to vew the partitions with ubuntu 12.04? or dose ubuntu even need ADB... linux seems very good at haveing the right drivers and software already available without installing to many extras.
not even sure your a linux desktop user but thought I would go ahead and ask.
Many thanks for everything
woodyjlw said:
I have not had windows on this pc for over 2 years now and I think ADB is MS only right? I do flash a lot but I normally run ultimate kernel cleaning script and plus run the wipes a couple times myself and sumtimes format cache partitons before I install a new rom.... I like to make sure I do most I can to clean before I flash...and I always run the LZ kernel Cause its AWESOME!! but I guess my question is how can I look to see if my partitons need to be cleaned.. on AOKP with LZ kernel at moment and it is smooth fast and no bugs or reboots. is there a way to vew the partitions with ubuntu 12.04? or dose ubuntu even need ADB... linux seems very good at haveing the right drivers and software already available without installing to many extras.
not even sure your a linux desktop user but thought I would go ahead and ask.
Many thanks for everything
Click to expand...
Click to collapse
Yeah, I'm completely windows free too...YAY! lol
You still need to install the adb binary/command and put it in your path. The good news is, it's very simple in Linux, unlike wincrapdows...
And then just follow the tutorial to check your partitions...

Ascend G6 L11 -- use whole internal memory for apps+data

Note: This is probably only helpful for people with a computer science or linux hacking background!
We all know the single biggest issue with this phone is the lack of internal memory for apps and app data. The internal partitioning looks like this:
/system 1 GB
/data 2 GB
sdcard0 4 GB -- lots of space that competes with external SD! Let's use it!
other stuff (tmp, boot, etc.) 1 GB
persona78 provided an excellent mod of the (most recent) stock ROM that gives you root and a working init.d:
https://forum.xda-developers.com/ascend-g6/general/root-upadtekinguser-zip-modded-extras-t3349679
This mod also enables to move apps to a new ext4 partition on the external SD card. My experience however is:
dalvik cache and app data (e.g. some social media apps caching videos etc.) will still fill up the /data partition
access to external SD, even a fast one, is much slower
if you also move app data to external SD, the phone becomes unusable (slow)
So I propose the following solution, successfully tested on my phone, that will use just short of 6 GB on the internal SD card for dalvik cache, apps and their data!
This is how to do it:
backup everything important from the phone
unlock bootloader and install the ROM from persona78, linked above. Make sure root works, adb works.
connect to a Linux machine via USB that has adb installed
select mass storage mode on the phone in the USB settings
Now in mass storage mode do the following:
the phone exposes a block device without partitioning (e.g. /dev/sdb) and a block device with partitioning (e.g. /dev/sdc, /dev/sdc1). the former is the internal storage (sdcard0), the latter external storage (sdcard1).
mount /dev/sdb to /mnt/internal and /dev/sdc1 to /mnt/external
rsync -a /mnt/internal/ /mnt/external/
umount /dev/sdb
mkfs.vfat -C /var/tmp/vfat 256000
dd if=/var/tmp/vfat of=/dev/sdb bs=1M (you can delete /var/tmp/vfat after this)
losetup /dev/loop0 /dev/sdb -o 262144000
mkfs.ext4 /dev/loop0
On the phone you can now change back the USB mode to MTP (but not to charge only -- a data mode is needed for adb to work).
Now run adb shell and obtain root in the shell via 'su'. In the adb root shell:
mkdir -p /data/sdext4
losetup -o 262144000 /dev/block/loop7 /dev/block/mmcblk0p25
mount -t ext4 /dev/block/loop7 /data/sdext4
in /data/sdext4, create two directories called 'data-app' and 'data-data'. Give them the respective permissions and group,ownership as with the current /data/app and /data/data directories.
cp -a /data/app/* /data/sdext4/data-app
cp -a /data/data/* /data/sdext4/data-data
rm -r /data/app/* /data/data/*
mount -o remount,rw /system
edit /etc/init.d/01AOBoot as follows
Content of /etc/init.d/01AOBoot:
#!/system/bin/sh
CONCURRENCY=makefile
# mount sdext4
losetup -o 262144000 /dev/block/loop7 /dev/block/mmcblk0p25
mount -t ext4 /dev/block/loop7 /data/sdext4
mount -o bind /data/sdext4/data-app /data/app
mount -o bind /data/sdext4/data-data /data/data
# change dalvik permissions
chmod 773 /data/dalvik-cache
# change scaling_min_freq to 300000
echo 300000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
Click to expand...
Click to collapse
Now run adb reboot. It is done.
Explanation: Apps and their data need to reside on an ext4 partition. sdcard0 however has to be vfat, otherwise the phone will always complain and ask to format it. We can also not change the internal storage partitioning. Therefore we simply hide a large ext4 filesystem behind a small vfat filesystem on the same partition. Apps will startup fast and run fast, and all media files can be put on the external sd card.
I know this is very exotic to most, but maybe there are a few people like me with the necessary background who would like to follow my example. Happy hacking!
Are you kidding me?
This is a great work that you did. My phone keeps complaining about low disk space but I was gonna use parted to resize the data partition.

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