On Wed, Oct 18, 2023 at 02:49:58PM -0700, Parke wrote: > > Unfortunately nothing so easy - snapshots will have the same inode > > number for their root as the parent subvolume, but new (empty) > > subvolumes get new inode numbers for their root inode. > > > > Perhaps we could sketch out a proper interface for this... > > Could Bcachefs communicate whether or not a directory is subvolume > somehow via the st_rdev field? Or does bcachefs already use st_rdev > for something else? > > (I am unfamiliar with st_rdev, its uses, and what restrictions the > kernel might place upon it.)
st_rdev is for device nodes, so no, that's not available. What about testing if st_dev is different from the parent directory?
