On Wed, Nov 08, 2023 at 09:27:44AM +0100, Christian Brauner wrote: > > What is that flag going to buy us? > > The initial list that Josef provided in > https://lore.kernel.org/linux-btrfs/20231025210654.GA2892534@perftesting > asks to give users a way to figure out whether a file is located on a > subvolume. Which I think is reasonable and there's a good chunk of > software out there that could really benefit from this. Now all of the > additional info that is requested doesn't need to live in statx(). But > that flag can serve as an indicator for userspace that they are on a > subvolume and that they can go to btrfs specific ioctls if they want to > figure out more details. Well, if we want to legitimize the historic btrfs behavior the way to find out is if st_dev changes without that being a mount point, so an extra flag would be redundant.
