Automounting EXT4 partition

[thameera]

I have a separate ext4 partition in my hard disk which I want to automount at login. So I added the following line in /etc/fstab:

/dev/sda4 /media/sda4 ext4 defaults 0 0

But now the device mounts in read-only mode. Need root access to change its contents. How can I mount the drive so that it does not need root privileges?

[coffeecat]

It's not actually being mounted read only, but owned by root, which is why you can't write to it.

Let it be mounted to /media/sda4, and then from a terminal:

sudo chown yourusername: /media/sda4

Substitute your login name for yourusername and don't forget the trailing colon.This has the interesting effect of changing the ownership of the ext4 filesystem rather than the mountpoint. You will now be able to write to it.

If you want other accounts to be able to write to it, you can also:

sudo chmod 777 /media/sda4

[Morbius1]

2 options:

(1) Take possession of the mount point:

sudo chown thameera /media/sda4

(2) Change permissions so everyone can access it:

sudo chmod 0777 /media/sda4

There are many variations of the two depending on your requirements.

[Morbius1]

coffeecat, You'll have to admit that was just plain spooky

[thameera]

@Morbius1, @coffeecat
Thanks a lot for the quick answers. I entered both commands in a terminal but still the contents are read-only :S
Any idea? Do I have to restart the system or something?

[coffeecat]

Thanks a lot for the quick answers. I entered both commands in a terminal but still the contents are read-only :S

Was sda4 mounted to /media/sda4? It won't work if the partition wasn't mounted. If the partition wasn't mounted you only modify the mountpoint and then those modifications get overridden when you mount it.

If you've already included that line in your /etc/fstab, then either reboot, or run:

sudo mount -a

Then run the chown and chmod commands again.

If you haven't yet edited your fstab with that line then:

sudo mount /dev/sda4 /media/sda4

... and run the chown and chmod commands.

[thameera]

No, I have already mounted the partition. Doesn't work though :S

[coffeecat]

coffeecat, You'll have to admit that was just plain spooky

No. Just great minds thinking alike.

To pick up your "take possession of the mount point", the interesting thing is that if the partition is mounted you actually take possession of the root of the filesystem, not the mountpoint (which I think is where the OP is going wrong atm). Which can be demonstrated if you do a 'ls -l' on /media before mounting the partition, after chown-ing it, and then again after unmounting it. It's a subtle but little-appreciated distinction. See my posts #7 and #12 in this thread for a little more:

http://ubuntuforums.org/showthread.php?t=1658937

Would you be so kind as to pass the word around on this? It deserves to be better known and understood.

[coffeecat]

No, I have already mounted the partition. Doesn't work though :S

OK. It should work. Let's get some more information. Post the contents of your whole /etc/fstab and the output of these commands:

sudo fdisk -lu
sudo blkid
ls -l /media
mount

[thameera]

Here are the results of the commands:


thameera@thameera-laptop:~$ sudo fdisk -lu

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x80028002

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 41015295 20506624 83 Linux
/dev/sda2 41017342 44920831 1951745 5 Extended
/dev/sda3 44920832 240232447 97655808 83 Linux
/dev/sda4 240232448 312580095 36173824 83 Linux
/dev/sda5 41017344 44920831 1951744 82 Linux swap / Solaris
thameera@thameera-laptop:~$ sudo blkid
/dev/sda5: UUID="0cad0cfe-d05f-401a-a101-802eff380e8b" TYPE="swap"
/dev/sda1: UUID="4f9d9f0f-aabd-4e4e-bb2b-bab26341fcae" TYPE="ext4"
/dev/sda3: UUID="cdfdf285-d3df-4978-b783-b908544fb41e" TYPE="ext4"
/dev/sda4: UUID="3b41917c-7475-46c1-9942-ba28a706bcd5" TYPE="ext4"
thameera@thameera-laptop:~$ ls -l /media
total 4
thameera@thameera-laptop:~$

Any ideas?