On Sun, Jun 10, 2018 at 6:57 AM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > On Mon, Jun 04, 2018 at 01:49:04AM -0700, Christoph Hellwig wrote: >> On Tue, May 29, 2018 at 04:43:07PM +0200, Miklos Szeredi wrote: >> > This is needed by the stacked ioctl implementation in overlayfs. >> >> EXPORT_SYMBOL_GPL for exporting random internals, please. Same >> for any following patches. > > *blink* > > Christoph, get real and RTFS - vfs_ioctl() simply calls ->unlocked_ioctl(); > all there is to it. > > This isn't even a case of "using that function establishes that the > caller is a derived work" - *anyone* who can see definition of > file_operations can bloody well open-code it. There isn't anything > establishing derivation here. > > Hell, it could've been a static inline in include/linux/fs.h and it would > neither differ from many other inlines in there nor need an export at all. > > This is really getting close to lxo-worthy levels of bogosity... > > More interesting question is why do we want to pass those ioctls to layers > in the first place, especially if it's something with different availability > (or, worse yet, argument layouts) before and after copyup. We don't. Obviously need to make sure to only ever do ioctl's in overlayfs that have a common definition across filesystems. Not a lot of those, luckily... Thanks, Miklos
