how to mount an ext3 filesystem with a smaller blocksize then device blocksize?

Question

I had an ext3 filesystem on my hard disk at /dev/hdc2 with a small 1024 byte blocksize. Now I recorded the whole filesystem on a DVD like this:

dd if=/dev/hdc2 of=/tmp/image.img
wodim -dev=/dev/scd0 /tmp/image.img

Now when I am trying to mount it, ext3 complains in dmesg:

EXT3-fs: blocksize 1024 too small for device blocksize 2048.

I guess that's because the DVD sector size is not 512 (like a hard disk), but 2048.

Is there some way to mount this? Without dd-ing the data back to a hard-disk of course, as I know that solution.

Answer 1

I've never tried this and am not going to burn a CD to test, but have you tried using an intermediate loop device, which uses /dev/scd0 as the backing "file", and specifying a blocksize for the loop device, to shim things into place?

The blocker would be if one of the tools is too smart and rejects it because the loop backing is not a regular file ...

Answer 2

I think you should write your image as file on ISO fs.