mounting loop-device on a 2048 byte/sector medium fails

[Peter Niemayer]

Hi,

first I thought this was some loop-AES specific issue, but now I know
it isn't: When I try to mount a filesystem on a loop device which
is in turn using a 2048 byte/sector medium (a magneto-optical drive
in my case), the mount fails though mkfs & fsck are happy.

The following script (tests done with kernel 2.4.18):

----------------------------------------------------------------------
#!/bin/sh

echo -n "blockdev /dev/sdb result: "
blockdev --getbsz /dev/sdb

losetup /dev/loop0 /dev/sdb

echo
echo -n "blockdev /dev/loop0 result: "
blockdev --getbsz /dev/loop0

echo
echo "mkfs output:"
mkfs -t ext2 /dev/loop0

echo
echo "fsck output:"
fsck.ext2 -f /dev/loop0

echo
echo "mount output:"

mount -t ext2 /dev/loop0 /mnt/floppy
------------------------------------------------------------------------

works just fine when the medium inserted into the MO-drive is a 512 byte/sector
medium, but when I put a 2048 byte/sector medium in the drive, this is the
resulting output:

------------------------------------------------------------------------
blockdev /dev/sdb result: 2048

blockdev /dev/loop0 result: 2048

mkfs output:
mke2fs 1.23, 15-Aug-2001 for EXT2 FS 0.5b, 95/08/09
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
77600 inodes, 155176 blocks
7758 blocks (5.00%) reserved for the super user
First data block=0
5 block groups
32768 blocks per group, 32768 fragments per group
15520 inodes per group
Superblock backups stored on blocks: 
        32768, 98304

Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 31 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

fsck output:
e2fsck 1.23, 15-Aug-2001 for EXT2 FS 0.5b, 95/08/09
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/loop0: 11/77600 files (0.0% non-contiguous), 2446/155176 blocks

mount output:
mount: wrong fs type, bad option, bad superblock on /dev/loop0,
       or too many mounted file systems
------------------------------------------------------------------------

Any idea?

Regards,

Peter Niemayer