problems mounting a ext2 disk image

Robert Lowe rl.sage at
Sat Jan 14 18:47:31 PST 2006


I have a dd image of a hard drive from a Linux box, which I'm trying to 
look at using a FreeBSD system. fdisk shows the following:

Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 131 (0x83),(Linux native)
     start 63, size 208782 (101 Meg), flag 80 (active)
         beg: cyl 0/ head 1/ sector 1;
         end: cyl 12/ head 254/ sector 63
The data for partition 2 is:
sysid 131 (0x83),(Linux native)
     start 208845, size 75971385 (37095 Meg), flag 0
         beg: cyl 13/ head 0/ sector 1;
         end: cyl 1023/ head 254/ sector 63
The data for partition 3 is:
sysid 130 (0x82),(Linux swap or Solaris x86)
     start 76180230, size 1975995 (964 Meg), flag 0
         beg: cyl 1023/ head 254/ sector 63;
         end: cyl 1023/ head 254/ sector 63

I was hoping that the memory disks could allow you to specify an offset 
(as is possible with Linux's loop device) and I could simply mount each 
partition directly from the entire image. However, I have not been able 
to find such an option. If such an option exists, can someone point me 
to it?

So as an alternative, I attempted the following (using the smaller /boot 
partition as a test case):

# dd bs=512 count=208782 if=111104.img of=boot.img skip=63
208782+0 records in
208782+0 records out
106896384 bytes transferred in 11.161832 secs (9576957 bytes/sec

# mdconfig -a -t vnode -f boot.img -u 0

# mount_ext2fs /dev/md0 /mnt/image/boot
mount_ext2fs: /dev/md0: Invalid argument

I have installed the e2fsprogs-1.38_1 port and running 'e2label 
boot.img' reports "/boot".

I am using FreeBSD 6, and have re-compiled my kernel (for other reasons) 
but I've ensured I included the following options:

device          md
options         EXT2FS

Am I missing something? Is md intended to be used in this way? Are there 
other methods I have overlooked? Any assistance would be greatly 

Thanks in advance,

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