don't bother with propagate_mnt() unless the target is shared

If the dest_mnt is not shared, propagate_mnt() does nothing -
there's no mounts to propagate to and thus no copies to create.
Might as well don't bother calling it in that case.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 7 insertions, 10 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 9db3ce397a83..d3fb9f00576e 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1653,16 +1653,14 @@ static int attach_recursive_mnt(struct mount *source_mnt,
                 err = invent_group_ids(source_mnt, true);
                 if (err)
                         goto out;
-        }
-        err = propagate_mnt(dest_mnt, dest_mp, source_mnt, &tree_list);
-        if (err)
-                goto out_cleanup_ids;
-
-        lock_mount_hash();
-
-        if (IS_MNT_SHARED(dest_mnt)) {
+                err = propagate_mnt(dest_mnt, dest_mp, source_mnt, &tree_list);
+                if (err)
+                        goto out_cleanup_ids;
+                lock_mount_hash();
                 for (p = source_mnt; p; p = next_mnt(p, source_mnt))
                         set_mnt_shared(p);
+        } else {
+                lock_mount_hash();
         }
         if (parent_path) {
                 detach_mnt(source_mnt, parent_path);
@@ -1685,8 +1683,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
         return 0;
 
  out_cleanup_ids:
-        if (IS_MNT_SHARED(dest_mnt))
-                cleanup_group_ids(source_mnt, NULL);
+        cleanup_group_ids(source_mnt, NULL);
  out:
         return err;
 }