On Thu, Sep 24, 2026 at 04:58:58PM +0530, Disha Goel wrote: > When overlayfs layers are passed as detached mount file descriptors > (opened with open_tree(OPEN_TREE_CLONE)), ovl_parse_layer() uses d_path() > to record the layer's path for display in mountinfo. > > d_path() walks up the mount tree to the process's filesystem root. For > detached mounts this walk stops at the anonymous namespace root instead > of the real system root, producing a short incorrect path like "/l1" > instead of the full absolute path. > > Export mnt_is_anon() from fs/namespace.c to detect detached mounts. In > ovl_parse_layer(), use dentry_path_raw() for detached mounts instead of > d_path(). dentry_path_raw() walks the dentry chain independent of mount > namespace and returns the correct fs-relative path. The path is > display-only; the actual layer_path used for mounting is always correct.
I think that's nonsensical you might end up with complete garbage. We should think about a custom format so userspace can "label" the file descriptors instead? Amir?
