On Tue, 15 Jun 2021 at 12:26, Ian Kent <raven@xxxxxxxxxx> wrote: > > Add a revision counter to kernfs directory nodes so it can be used > to detect if a directory node has changed during negative dentry > revalidation. > > There's an assumption that sizeof(unsigned long) <= sizeof(pointer) > on all architectures and as far as I know that assumption holds. > > So adding a revision counter to the struct kernfs_elem_dir variant of > the kernfs_node type union won't increase the size of the kernfs_node > struct. This is because struct kernfs_elem_dir is at least > sizeof(pointer) smaller than the largest union variant. It's tempting > to make the revision counter a u64 but that would increase the size of > kernfs_node on archs where sizeof(pointer) is smaller than the revision > counter. > > Signed-off-by: Ian Kent <raven@xxxxxxxxxx> Reviewed-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
