Merge tag 'gcc-plugins-v4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index b3b115bd4e1ee397f01bf0930f5f9900be5878bf..8bd3e4d448b9f07a8aa148c8d08c092f45471a7c 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3462,8 +3462,9 @@ static void mntns_put(struct ns_common *ns)
 static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns)
 {
        struct fs_struct *fs = current->fs;
-       struct mnt_namespace *mnt_ns = to_mnt_ns(ns);
+       struct mnt_namespace *mnt_ns = to_mnt_ns(ns), *old_mnt_ns;
        struct path root;
+       int err;
 
        if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) ||
            !ns_capable(current_user_ns(), CAP_SYS_CHROOT) ||
@@ -3474,15 +3475,18 @@ static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns)
                return -EINVAL;
 
        get_mnt_ns(mnt_ns);
-       put_mnt_ns(nsproxy->mnt_ns);
+       old_mnt_ns = nsproxy->mnt_ns;
        nsproxy->mnt_ns = mnt_ns;
 
        /* Find the root */
-       root.mnt    = &mnt_ns->root->mnt;
-       root.dentry = mnt_ns->root->mnt.mnt_root;
-       path_get(&root);
-       while(d_mountpoint(root.dentry) && follow_down_one(&root))
-               ;
+       err = vfs_path_lookup(mnt_ns->root->mnt.mnt_root, &mnt_ns->root->mnt,
+                               "/", LOOKUP_DOWN, &root);
+       if (err) {
+               /* revert to old namespace */
+               nsproxy->mnt_ns = old_mnt_ns;
+               put_mnt_ns(mnt_ns);
+               return err;
+       }
 
        /* Update the pwd and root */
        set_fs_pwd(fs, &root);