Thread: Ubuntu Mount Root Disk Image As A Loop Device Using Offset

Hi guys..I had installed Ubuntu from wubi installer on my friends .It was messed up, as it was on top of NTFS and due to frequent power cuts..now I have root.disk file ( 30 Gib)..
Please tell me how to use that,,( mount ??) .. , btw..ubuntu will be highly stable if its installed on top of NTFS ..lol

Thanks

Do you want to access image file from Linux or Windows?

I want to access it from ubuntu..
I am trying to mount it..but getting error

root.disk is in /media/media/

sudo mount -o loop /media/media/root.disk /vdisk
mount: wrong fs type, bad option, bad superblock on /dev/loop1,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so


fdisk -l output




I want to mount it in sdb

Thanks

Run file command on it and see what it reports back:

Code:

file /media/media/root.disk

Linux rev 1.0 ext4 filesystem data, UUID=f11da96c-c02a-48f9-b6ec-37fe3c0d4611 (needs journal recovery) (extents) (large files) (huge files)

Try

Code:

mkdir /vdisk
mount -o loop -t ext4 /media/media/root.disk /vdisk

If above failed than you need to get offset and mount it with the same:

Code:

fdisk -ul /media/media/root.disk

Look out for sector number. If there are more partition you need to calculate offset and than mount it as follows:

Code:

mount -o loop,offset=XYZ  -t ext4 /media/media/root.disk /vdisk

XYZ is offset and calculated as n * 512. Consider the follwoing example:

Code:

fdisk -ul image.img
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 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: 0xf0000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048    31999999    15998976   82  Linux swap / Solaris
/dev/sda2        32002046   976771071   472384513    5  Extended
/dev/sda5        32002048   976771071   472384512   83  Linux

In this case 2048 is starting offsent for /dev/sda1 and 32002048 is for /dev/sda5 so to mount /dev/sda5 you calculate it as 32002048 * 512 = 16385048576 and mount it as follows:

Code:

mount -o loop,offset=16385048576  -t ext4 /media/media/root.disk  /vdisk

Thanks it worked

Originally Posted by nixcraft

Try

Code:

mkdir /vdisk mount -o loop -t ext4 /media/media/root.disk /vdisk

If above failed than you need to get offset and mount it with the same:

Code:

fdisk -ul /media/media/root.disk

Look out for sector number. If there are more partition you need to calculate offset and than mount it as follows:

Code:

mount -o loop,offset=XYZ  -t ext4 /media/media/root.disk /vdisk

XYZ is offset and calculated as n * 512. Consider the follwoing example:

Code:

fdisk -ul image.img 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 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: 0xf0000000     Device Boot      Start         End      Blocks   Id  System /dev/sda1   *        2048    31999999    15998976   82  Linux swap / Solaris /dev/sda2        32002046   976771071   472384513    5  Extended /dev/sda5        32002048   976771071   472384512   83  Linux

In this case 2048 is starting offsent for /dev/sda1 and 32002048 is for /dev/sda5 so to mount /dev/sda5 you calculate it as 32002048 * 512 = 16385048576 and mount it as follows:

Code:

mount -o loop,offset=16385048576  -t ext4 /media/media/root.disk  /vdisk

Oh,thanks a lot for this