On Tue, 01 Jun 2010 23:56:20 -0400 Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote: > On Wed, 2010-06-02 at 13:41 +1000, Neil Brown wrote: > > NFS needs a unique identifier for a filesystem to be able to export it. > <snip> > > Can anyone suggest a better way to get a good uuid for a btrfs filesystem? > > How about just adding the btrfs subvolid to the filehandle and using > that to remove the ambiguity? The filehandle has two parts - one part identifies the filesystem (i.e. vfsmnt), the other identifies the file (the dentry). We would need to get the btrfs subvolid into the filesystem part, and that is set (and looked-up) by mountd in user-space. I think you are suggesting getting the btrfs kernel module to put the subvolid in the filehandle, but that would only go in the 'file' part of the handle, so it would not be sufficient. We need a user-space program - preferably without too much filesystem-specific info - to be able to differentiate subvolumes. Thanks, NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
