On Wed, Jun 13, 2007 at 04:08:30AM +0100, Christoph Hellwig wrote: > On Tue, Jun 12, 2007 at 04:14:39PM -0400, Chris Mason wrote: > > > Aside from folding snapshot history into the origin's namespace... It > > > could be possible to have a mount.btrfs that allows subvolumes and/or > > > snapshot volumes to be mounted as unique roots? I'd imagine a bind > > > mount _could_ provide this too? Anyway, I'm just interested in > > > understanding the vision for managing the potentially complex nature > > > of a Btrfs namespace. > > > > One option is to put the real btrfs root into some directory in > > (/sys/fs/btrfs/$device?) and then use tools in userland to mount -o bind > > outside of that. I wanted to wait to get fancy until I had a better > > idea of how people would use the feature. > > We already support mounting into subdirectories of a filesystem for > nfs connection sharing. The patch below makes use of this to allow > mounting any subdirectory of a btrfs filesystem by specifying it in > the form of /dev/somedevice:directory and when no subdirectory > is specified uses 'default'. Neat, thanks Christoph, this will be much nicer longer term. I'll integrate it after I finish off -enospc. > To make this more useful btrfs directories > should grow some way to be marked head of a subvolume, They are already different in the btree, but maybe I'm not 100% sure what you mean by marked as the head of a subvolume? > and we'd need > a more useful way to actually create subvolumes and snapshots without > fugly ioctls. One way I can think of that doesn't involve an ioctl is to have a special subdir at the root of the subvolume: cd /mnt/default/.snaps mkdir new_snapshot rmdir old_snapshot cd /mnt mkdir new_subvol rmdir old_subvol -chris - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
