Is there a lightweight copy from one subvolume to another?

If I have
/mnt/btrfs1/subvol1
/mnt/btrfs1/subvol2

Can I copy/move data from subvol1 to subvol2 without having to physically copy all the blocks as if it were an entirely different filesystem?

reflink doesn't work for this:
gargamel [mc]# cp -av --reflink=always misc/olympic Video/misc/
misc/olympic' -> Video/misc/olympic'
misc/olympic/file.avi' -> Video/misc/olympic/file.avi'
cp: failed to clone Video/misc/olympic/file.avi' from misc/olympic/file.avi': Invalid cross-device link

Was there another way?

Thanks,
Marc
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Due to what I understand is some VFS limitation, you can only reflink-copy between subvolumes under one Linux mountpoint. If /mnt/btrfs1 provides access to all subvolumes, you should be able to copy between them through that path, but you won't be able to copy them across mounts, even --bind ones.

Quoted 4 lines

gargamel [mc]# cp -av --reflink=always misc/olympic Video/misc/
misc/olympic' -> Video/misc/olympic'
misc/olympic/file.avi' -> Video/misc/olympic/file.avi'
cp: failed to clone Video/misc/olympic/file.avi' from misc/olympic/file.avi': Invalid cross-device link

Quoted 5 lines · Maxdamantus

Due to what I understand is some VFS limitation, you can only reflink-copy between subvolumes under one Linux mountpoint. If /mnt/btrfs1 provides access to all subvolumes, you should be able to copy between them through that path, but you won't be able to copy them across mounts, even --bind ones.

That was exactly my understanding too.

Quoted 4 lines

Quoted 4 lines

gargamel [mc]# cp -av --reflink=always misc/olympic Video/misc/
misc/olympic' -> Video/misc/olympic'
misc/olympic/file.avi' -> Video/misc/olympic/file.avi'
cp: failed to clone Video/misc/olympic/file.avi' from misc/olympic/file.avi': Invalid cross-device link

The test above was done in /mnt/btrfs_pool1 and failed as shown here.

Yet

gargamel:/mnt/btrfs_pool1# btrfs subvolume list .
ID 257 top level 5 path misc
ID 258 top level 5 path Video
ID 259 top level 5 path media
ID 260 top level 5 path Sound
ID 261 top level 5 path zoneminder
ID 262 top level 5 path other

Aah, but it looks like this was my problem:
'Preparing to replace coreutils 8.13-3.2 (using .../coreutils_8.21-1_i386.deb) ...

now cp --reflink works as expected.

Thanks,
Marc