btrfs subvolume as an iSCSI target?

I've been combing the web for a couple days, and most hits I'm finding regarding using a btrfs subvolume as an iSCSI target are posts from the 2009/2010 timeframe stating that that functionality is broken. I'm working on a couple projects here, and one of those involves the research into iSCSI targets and initiators, and the testing thereof. I have an F20 system with a 1.3TB btrfs master subvolume (across three dissimilar devices), and want to create a subvolume within that to serve as an iSCSI target. The traditional methods, specifically those mentioned in the Fedora Wiki and the tgtadm man pages, place the emphasis on using devices (/dev/sdx) or files (dd if=/dev/zero of=/array/target1 bs=1k count=1). I realize that using the file is probably the easiest thing to do in this instance, but that's not the point of my project - I am intentionally trying to designate the btrfs subvolume as the target. The issue I believe that is going to stop me is that tgtadm expects a block device as the target, and btrfs does not provide that. Is there a workaround, other than using a file in the subvolume as the target? Is there work in progress to enable this feature, either in the scsi-target-utils package or within the btrfs framework? -- Dan Mossor Systems Engineer at Large Fedora QA Team Volunteer FAS: dmossor IRC: danofsatx San Antonio, Texas, USA