HI all, >----Messaggio originale---- >Da: hpa@xxxxxxxxx >Data: 20/06/2012 5.22 >A: "cwillu"<cwillu@xxxxxxxxxx> >Cc: <helmut@xxxxxxxxx>, <linux-btrfs@xxxxxxxxxxxxxxx> >Ogg: Re: Subvolumes and /proc/self/mountinfo > > >The concept of what is the "root" and what is the "path" is >straightforward for lesser filesystems: the root of the filesystem is >defined by the root inode, and the path is a unique sequence of >directories from that root. Note that this is completely independent of >how the filesystem was mounted when the boot loader was installed. For the aim of the discussion, I would like to highlight a small difference between the path of the subvolume and the subvolume-id. The latter is the specific subvolume, the former is a "functional" reference to this subvolume. For example, in my root btrfs I have two two subvolumes: __active (the root filesystem of my system) and (__rollback the last "good" copy) If I swap (via a rename) __active and __rollback, in the next boot my system uses a "good" copy of the root filesystem. This is a simple way to swap two subvolumes, without involving the boot logic Instead if I had tracked the subvolume-id, to swap the root filesystem I would have update the boot logic. I suspect that could exists other cases where it is preferable to track the subvolume-id instead the path. However what I would highlight it is the two ways aren't equal. BR G.Baroncelli -- 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
