amd64/164516: unable to mount EXT2 filesystem

[vermaden]

>Number:         164516
>Category:       amd64
>Synopsis:       unable to mount EXT2 filesystem
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jan 26 15:30:11 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     vermaden
>Release:        9.0-STABLE
>Organization:
>Environment:
FreeBSD hostname 9.0-STABLE FreeBSD 9.0-STABLE #0 r230041: Fri Jan 13 09:31:26 CET 2012     root at hostname:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
Here are steps taken to create, check and (try to) mount a new EXT2 filesystem:

# dd < /dev/zero > FILE bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes transferred in 0.093486 secs (1121641617 bytes/sec)

# mdconfig.sh -c FILE
IN: created vnode at /dev/md0

# mdconfig.sh -l
md0     vnode     100M  /usr/home/vermaden/FILE

# mkfs.ext2 -I 128 /dev/md0
mke2fs 1.41.14 (22-Dec-2010)
Filesystem label=
OS type: FreeBSD
Block size=1024 (log=0)
Fragment size=1024 (log=0)
Stride=0 blocks, Stripe width=0 blocks
25688 inodes, 102400 blocks
5120 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=67371008
13 block groups
8192 blocks per group, 8192 fragments per group
1976 inodes per group
Superblock backups stored on blocks: 
        8193, 24577, 40961, 57345, 73729

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

This filesystem will be automatically checked every 21 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

# tune2fs -l /dev/md0 | grep 'Inode size'
Inode size:               128

# file -s /dev/md0
/dev/md0: Linux rev 1.0 ext2 filesystem data

# fsck.ext2 /dev/md0
e2fsck 1.41.14 (22-Dec-2010)
/dev/md0: clean, 11/25688 files, 4800/102400 blocks

# mount -t ext2 /dev/md0 /mnt/tmp0
mount: /dev/md0 : Operation not supported by device



>How-To-Repeat:
# mount -t ext2 /dev/md0 /mnt/tmp0
mount: /dev/md0 : Operation not supported by device
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: