overlayfs fixes

Hi Linus,

Please pull from:

git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git overlayfs-next

This fixes minor issues with the multi-layer update in v4.0.

Thanks,
Miklos

---
hujianyang (3):
ovl: print error message for invalid mount options
ovl: check lowerdir amount for non-upper mount
ovl: upper fs should not be R/O

---
 fs/overlayfs/super.c | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)