Ubuntu – Why does Ubuntu apply separate permissions to partitions mounted with the same parameters

12.04fstabmountpermissions

Here's my partition setup. I've shortened the UUIDs for readability, and, before anyone asks, I've carefully checked that I copied the correct UUIDs into /etc/fstab.

me@ubuntu:/$ sudo blkid
/dev/sda1: UUID="a6205dda..." TYPE="ext3" 
/dev/sda2: UUID="99397b94..." TYPE="ext3" LABEL="DATA1" SEC_TYPE="ext2"  
/dev/sda3: UUID="135523f8..." TYPE="ext3" LABEL="DATA2" SEC_TYPE="ext2" 
/dev/sda4: UUID="a1e4d70f..." TYPE="swap"

Here's how my fstab is configured:

me@ubuntu:/media/DATA2$ cat /etc/fstab
# <file system>     <mount point>   <type>  <options>               <dump>  <pass>
proc                /proc           proc    nodev,noexec,nosuid     0   0
UUID=a6205dda...    /               ext3    errors=remount-ro       0   1
UUID=99397b94...    /media/DATA1    ext3    rw,nosuid,nodev,user    0   0
UUID=135523f8...    /media/DATA2    ext3    rw,nosuid,nodev,user    0   0
UUID=a1e4d70f...    none            swap    sw                      0   0

(Does whitespace matter in fstab? For example, does each field have to be separated by a single tab? Or any number of tabs?)

I've set up the mount points for the partitions in the /media directory:

me@ubuntu:/media$ ls -al
drwxr-xr-x  4 root root 4096 Feb 18 09:17 .
drwxr-xr-x 23 me   me   4096 Feb 13 10:08 ..
drwxr-xr-x  2 me   me   4096 Feb 13 16:03 DATA1
drwxr-xr-x  2 me   me   4096 Feb 13 16:03 DATA2

Thanks to the entries in the fstab, I can mount the partitions as an ordinary user, without any problems:

me@ubuntu:/media$ mount DATA1
me@ubuntu:/media$ mount DATA2
me@ubuntu:/media$ mount
/dev/sda1 on / type ext3 (rw,errors=remount-ro)
/dev/sda2 on /media/DATA1 type ext3 (rw,noexec,nosuid,nodev,user=me)
/dev/sda3 on /media/DATA2 type ext3 (rw,noexec,nosuid,nodev,user=me)

But here's the problem: DATA2 is mounted as root, which means I don't have write permissions for it. Why the difference, and what can I do to ensure DATA2 is mounted with the same permissions as DATA1?

me@ubuntu:/media$ ls -al
drwxr-xr-x  4 root root 4096 Feb 18 09:17 .
drwxr-xr-x 23 me   me   4096 Feb 13 10:08 ..
drwxrwxrwx 10 me   me   4096 Feb 18 09:20 DATA1
drwxr-xr-x  3 root root 4096 Feb 13 13:57 DATA2

For reference, I'm using Ubuntu 12.04.2 LTS. Also, the order in which I mount the partitions has no effect on their permissions; they always have the permissions shown above.

Best Answer

As the ext3 file system supports Unix style permissions the permissions stored on the file system are used, just like on your / partition.

If you want all the files in DATA2 and its subfolders to belong to the user and group me you can use

chown -R me:me /media/DATA2

to change the owner.