Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs fixes from Miklos Szeredi:
 "Fix a regression in 4.14 and one in 4.13. The latter is a case when
  Docker is doing something it really shouldn't and gets away with it.
  We now print a warning instead of erroring out.

  There are also fixes to several error paths"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: fix regression caused by exclusive upper/work dir protection
  ovl: fix missing unlock_rename() in ovl_do_copy_up()
  ovl: fix dentry leak in ovl_indexdir_cleanup()
  ovl: fix dput() of ERR_PTR in ovl_cleanup_index()
  ovl: fix error value printed in ovl_lookup_index()
  ovl: fix may_write_real() for overlayfs directories

Documentation/filesystems/overlayfs.txt

@@ -210,8 +210,11 @@ path as another overlay mount and it may use a lower layer path that is
 beneath or above the path of another overlay lower layer path.
 
 Using an upper layer path and/or a workdir path that are already used by
-another overlay mount is not allowed and will fail with EBUSY.  Using
+another overlay mount is not allowed and may fail with EBUSY.  Using
 partially overlapping paths is not allowed but will not fail with EBUSY.
+If files are accessed from two overlayfs mounts which share or overlap the
+upper layer and/or workdir path the behavior of the overlay is undefined,
+though it will not result in a crash or deadlock.
 
 Mounting an overlay using an upper layer path, where the upper layer path
 was previously used by another mounted overlay in combination with a