Revert "fix mismerge with Trond's stuff (create_mnt_ns() export is gone now)"

This reverts commit e9496ff46a20a8592fdc7bdaaf41b45eb808d310. Quoth Al:

 "it's dependent on a lot of other stuff not currently in mainline
  and badly broken with current fs/namespace.c.  Sorry, badly
  out-of-order cherry-pick from old queue.

  PS: there's a large pending series reworking the refcounting and
  lifetime rules for vfsmounts that will, among other things, allow to
  rip a subtree away _without_ dissolving connections in it, to be
  garbage-collected when all active references are gone.  It's
  considerably saner wrt "is the subtree busy" logics, but it's nowhere
  near being ready for merge at the moment; this changeset is one of the
  things becoming possible with that sucker, but it certainly shouldn't
  have been picked during this cycle.  My apologies..."

Noticed-by: Eric Paris <eparis@redhat.com>
Requested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index d5b112bcf3de..ce907efc5508 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2648,13 +2648,21 @@ out_freepage:
 static int nfs_follow_remote_path(struct vfsmount *root_mnt,
                 const char *export_path, struct vfsmount *mnt_target)
 {
+        struct mnt_namespace *ns_private;
         struct nameidata nd;
         struct super_block *s;
         int ret;
 
+        ns_private = create_mnt_ns(root_mnt);
+        ret = PTR_ERR(ns_private);
+        if (IS_ERR(ns_private))
+                goto out_mntput;
+
         ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
                         export_path, LOOKUP_FOLLOW, &nd);
 
+        put_mnt_ns(ns_private);
+
         if (ret != 0)
                 goto out_err;