Chris Mason wrote: > On Sat, Nov 21, 2009 at 12:31:06AM +0100, Goffredo Baroncelli wrote: [...] > > My concern is about the btrfs user interface. > > The biggest difficult that I had to learn the btrfs capabilities is its "user- > > interface". I have to admit to be not the smartest person, but I spent a lot > > of time in order to understand which was the difference between a btrfs > > subvolume creation and a "mkfs + mount". > > Finally I concluded that there no is difference (except the COW behaviour and > > other implementation detail). My impression was that in some area too often > > the VFS and btrfs do the same things. [*] > > The point is that if btrfs do the same things of VFS, this may be called as > > "flexibility". > > But the history has highlight that from a long term point of view is the > > orthogonality of the subsystems that leads to the flexibility of the system.. > > Well, btrfs is using the VFS to expose the subvolumes. Basically a > subvolume is a special directory. Let me explain better: what I would say was to expose the sub-volume content *only* with a command like "mount -o subvol=<name>". To day when I create a snapshot, automatically it is placed in the btrfs filesystem with the snapshot name. IIRC when I move (rename) the directory I change the subvolume/snapshot name also. Yes, I can remount the sub-volume with the mount command anywhere and with an arbitrary name. In fact the thing that seems strange to me is that when I create a snapshot, immediately it is mounted: it is not a real problem, it is only a strange behaviour. The "standard" behaviour is to create the file-system and then mount it: two separate actions. > -chris Goffredo -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
