On Fri, Jun 12, 2020 at 02:42:37PM +0800, Qu Wenruo wrote: > Currently btrfs uses unique anonymous block device for each root, which > sometimes can be overkilled, especially considering how lightweight > btrfs snapshot is. In my understanding the subvolumes must have a unique anon bdev associated, to appear as different inode number namespaces. This goes back to the beginning and we can't change that. See 3394e1607eaf870eb. > Although this brings a big user visible interface change, before this > patch each subvolume has its own bdev for stat(), now all subvolumes > shares the same bdev. > I'm not sure how many users will be affected. A 'big user visible interface change' should be a strong sign to do the research first before writing the code.
