How to convert EXT4 to EXT3? - Android Software Development

As the title states, my SD currently runs an EXT4 partition, however after reading around on these forums not all roms support EXT4 yet and most want EXT3 in order to work properly.. Upgrading EXT is easy im using RA Recovery Image, however how do you go from an EXT4 back to an EXT3?

I would think you'd have to repartition the card, well thats how I went about it.

It's tricky. usually, once you upgrade to ext4 you can't go back to ext3 without repartitioning.. but there's a work around...
you can turn off the ext4 "features" from a ext4 partition and mount it as ext3....
"mount -t ext4 /dev/yourpartition /mnt"
that would be the basic command. Needs to be rewritten for your particular situation.
You're better off just repartitioning lol.

Related

SD Partitioning from Recovery

How long should it take? I have done it a couple times before so that I could use Apps2SD and then back to a single partition to use Froyo, then back to an ext partition set up. Now, I was trying to partition back to a single FAT32 partition, but it seems like it has been doing it for a lot longer than it previously did. Is it stuck in a loop, or should I just battery pull and assume it worked?
I just checked it. It didn't partition anything. Weird. I'll try again.
joshmerd said:
I just checked it. It didn't partition anything. Weird. I'll try again.
Click to expand...
Click to collapse
If you're checking for the partition in Windows, then you're making the same mistake that I first made. Ext2 and Ext3 partitions are Linux partitions, so windows doesn't see them. If you partitioned using Amon_RA's recovery, make sure you also converted from Ext2 to Ext3. Also, make sure you did NOT convert to Ext4--Zanfur's OC Kernel does not currently support Ext4, so this won't work on any of the Eris ROMs. Hope this helps!
Some ROMS seem to require ext2 and some require ext3 apparently. Is it possible to create a softlink so the phone would see both ext2 and ext3 or is it even possible due to differences in the filesystem structure? I'm thinking along the lines of using something like "ln -s"...

[Q] Ext3 or ext4

Is it possible to have our data sectors written as ext3 or ext4. I remember from my g1 days that they are supposed to be faster then ext2 never heard a diffenate on that though.... Personal experience is ext3 is fastest but thats just experience and imo, nothing to prove that...sorry if this had been asked I searched and dididn't come up with anything..
A tutorial on how to create a swap partition is also interesting.
Sorry for my english...
Ext2 is used because the way the data is accessed under ext3 and ext4 reduces the life of an SSD. Ext3 and Ext4 would be fine if you used HDDs, but we don't have a slot that big on our HD2s.
Thanks for the response, but I think some of us are willing to cook a sd card if it improves performance.
Sent from my HTC HD2 using XDA App
how de we create ext4 partition?

Nandroid won't backup my ext4 partition?

I'm currently using data2ext with B 0.8, and I have a 2gb ext4 partition. I tried performing a backup using BlaY0's "Customized CWM 3.0.1.3 fake-flash with ext4 support". However, I get a message saying something along the lines of "Couldn't mount sd-ext. Sd-ext backup may not be supported on this device."
Any ideas? Is it unable to backup a ext partition larger than 1gb? Is there any alternative to a nandroid backup?
EDIT: Damn, is this cause I cheated when partitioning the SD card?
I guess the problem is in ext4 feature huge_files. Even tho my customized CWM has ext4 support, it lacks huge files support (files over 2TB). This feature however is set by default when formatting ext4 partition. It can be turned off using tune2fs. Consult mr. Google on how to use tune2fs.
Sent from my HTC Legend
i tried turning off huge_file support but i still cant nandroid the ext4 partition created with the customised fake flash.
from adb shell in latest CWM recovery i tried:
tune2fs -O ^huge_file /dev/block/mmcblk0p2
/data/data/com.koushikdutta.rommanager/files/e2fsck -fpDC0 /dev/block/mmcblk0p2
Click to expand...
Click to collapse
then rebooted but still not love with nandroid mountind the ext4 partition
fixed my problem:
i had reverted to using CWM 2.5.0.7 gui / update.zip which does not support ext4
so going back to blay0's custom update.zip (3.0.1.3) I can now nandroid backup my ext4 partition. (i have still got huge_files turned off as per above)
Just dunno how to use blay0s version with rom recovery gui, but no biggie

Format & Use MicroSD W/ ext4?

Hey guys, for a couple reasons I'd like to be able to format my micro SD card with the ext4 file system.
I can format my card using a computer running Ubuntu, but the card will not mount.
I'm running CM10 on my P3113.
Is there any simple way to do this?
It seems like it'd be best to use vold to mount the sdcard, but that doesn't support ext4 I guess?
Just wondering...
Ext4 support has to come from kernel.
???
Literally every other mounted filesystem on the CM10 ROM I use is ext4...
I'm gonna try mounting via an init.d script.
We'll see if that works...
Solved this one, it was easier than I expected.
You need to format the card, and then mount it at boot via a script.
CM9 and 10 support init.d scripts, so I have a script file at /system/etc/init.d/95sdcardext4
with this contents:
Code:
#!/system/xbin/sh
# Mount SD Card Ext4 Script
mount -rw -t ext4 /dev/block/mmcblk1p1 /storage/sdcard1
This runs very early in the boot up process, and ext4 partitions mount basically instantly, so everything is working as expected so far.
More tests need to be done, but I'm fairly certain I can package this up in a flashable ZIP package.
Brilliant !
ext4 is anyways far better than fat32 except Windows/Mac compatibility.
Awaiting your stable work
It will work on a s5670 running cm10 jb4.1.1?
I just have to create a file with that lines and put it in /system/etc/init.d/95sdcardext4 ?????????
I cannot get link2sd to mount the ext4 partition.
Thx
DivinityCycle said:
Solved this one, it was easier than I expected.
You need to format the card, and then mount it at boot via a script.
CM9 and 10 support init.d scripts, so I have a script file at /system/etc/init.d/95sdcardext4
with this contents:
Code:
#!/system/xbin/sh
# Mount SD Card Ext4 Script
mount -rw -t ext4 /dev/block/mmcblk1p1 /storage/sdcard1
This runs very early in the boot up process, and ext4 partitions mount basically instantly, so everything is working as expected so far.
More tests need to be done, but I'm fairly certain I can package this up in a flashable ZIP package.
Click to expand...
Click to collapse
Sorry about that, I don't have one of these anymore. I had a P3113, but switched to a T869, which is a very similar device but has 4G and some different stuff going on under the hood.
My brief ext4 experiment was honestly not that big of a deal. I ended up going back to FAT32 because the benefits didn't outweigh the annoyances.
The biggest issue I had was I couldn't figure out how to make the file system permissions behave in the same highly permissive way that FAT32 does. I ran into several force closes and other things that resulted from apps not being to read / write stuff on the card that they should have been able to. I know you can CHMOD stuff, and a boot script could chmod everything on the card, but that seems like a bandaid.
Maybe there's a way to make the permissions behave a specific way via the mount parameters? I didn't investigate deeply enough because my life got busy, and during the changeover to the new tab it was just easier to go back to FAT32. Also my new tab has 16GB of internal storage, so I've been much less stressed about storage.
Ok folks.. ...reviving an ancient thread....from good ol days when it 'KISS' was common for Android.
What about android 7+ onward . All this stuff is deprecated. My 128gb is cut into 3 Ext4's.
(I need a journaled FS - that story a lil later )
I can mount easily but problem is apps cant see it and its all got to do with mount space concept.
I am Su'ed via Magisk
Can someone post a step by step guide to mount ext4 on 7+

/system stuck on VFAT file system

So I've been trying to do a lot of things and I must have messed up something along the way. I followed a video that tells you to change /system to vfat and then back to ext4 to fix it but now I cannot change it back to ext4 and I can't boot flash my phone since roms need system to be ext4.

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