loopback over reiserfs broken in 2.6.1-mm1

[Andy Lutomirski <luto@myrealbox.com>]

Hi-

on 2.6.1-mm1, where /var is reiserfs:

[root@luto var]# dd if=/dev/zero of=foo count=1024
1024+0 records in
1024+0 records out
[root@luto var]# losetup /dev/loop0 foo
ioctl: LOOP_SET_FD: Invalid argument

This works on ext3 and XFS, and it worked on -test11.  It does not work 
in /tmp or anything bind-mounted off reiserfs, but it does work in bind 
mounts from ext3.  Any ideas?

/proc/mounts:

rootfs / rootfs rw 0 0
/dev/root / ext3 rw,noatime 0 0
none /dev devfs rw 0 0
/proc /proc proc rw 0 0
/sys /sys sysfs rw 0 0
usbdevfs /proc/bus/usb usbdevfs rw 0 0
none /dev/pts devpts rw 0 0
none /dev/shm tmpfs rw 0 0
/dev/hda5 /usr reiserfs rw,noatime 0 0
/dev/hda6 /var reiserfs rw,nosuid 0 0
/dev/hda7 /data xfs rw,noatime,nosuid,usrquota,logbufs=8 0 0
tmpfs /dev/shm tmpfs rw 0 0
/dev/hda6 /var/tmp reiserfs rw,nosuid 0 0


--Andy