Testing new send/receive: "ERROR: could not resolve root_id for"

[Robert Buhren <robert@robertbuhren.de>]

Hello,

i wanted to test the new send/receive feature and i can't manage to send 
a snapshot to a file. I always get the error
"ERROR: could not resolve root_id for".

I'm using kernel 3.6-rc1 and the latest btrfs progs from git.

This is what i'm doing:

mount -o subvolid=0,discard,compress=lzo /dev/sda4 /mnt/ROOT_BTRFS

[root@robert-laptop mnt]# /home/robert/ArchLinux/btrfs-progs/btrfs 
subvolume list ROOT_BTRFS/
ID 256 top level 5 path btrfs_root <--- my rootfs subvolume
ID 265 top level 5 path btrfs_root-11082012-0023      <--- a "normal" 
snapshot"
ID 268 top level 5 path root_send <--- a read only snapshot i try to use 
with send

[root@robert-laptop ~]# cd /mnt/ROOT_BTRFS/
[root@robert-laptop ROOT_BTRFS]# 
/home/robert/ArchLinux/btrfs-progs/btrfs send root_send > outROOT
At subvol root_send
ERROR: could not resolve root_id for /mnt/ROOT_BTRFS/root_send

Am i somehow misunderstanding how the send/receive feature should work? 
My idea is to send the "root_send" snapshot to a file and then replay 
that file later on a backup btrfs partition. Once i've done that i can 
just send incremental differences to the backup partition. Is that how 
"send/receive" is supposed to work?

If you need further information just tell me.

Thanks in advance,

Robert


PS: Please respond to my email address as i'm not subscribed to the list.