On Wed, Jan 13, 2021 at 02:34:45PM +0000, Trond Myklebust wrote: > On Wed, 2021-01-13 at 08:12 +0000, Christoph Hellwig wrote: > > FYI, if people really want to use some sort of subtree exports, for > > XFS > > (and probably ext4) we encode the project id into the file handle and > > use the hierarchical project ID inheritance that we already use for > > project quotas. > > You'd basically need something along the lines of a NetApp qtree. > > i.e. a persisted tag that can label all the files and directories in a > subtree, and that is used to enforce a set of rules that are generally > normally associated with filesystems. So no renames from objects inside > the subtree to directories that lie outside it. No hard links that > cross the subtree boundary. That is the XFS project ID, which ext4 has also picked up a few years ago.
