---

yaml
---
r: 177203
b: refs/heads/master
c: 3b6cee7
h: refs/heads/master
i:
  177201: e11e252
  177199: 5044ee8
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: eb4c86c6a5adec423c9e615d4937fdddd06a16c5
+refs/heads/master: 3b6cee7bc4b2f7858e9202293104acda8826bb68

trunk/fs/nfsd/vfs.c

@@ -99,8 +99,16 @@ nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
 
 	exp2 = rqst_exp_get_by_name(rqstp, &path);
 	if (IS_ERR(exp2)) {
-		if (PTR_ERR(exp2) != -ENOENT)
-			err = PTR_ERR(exp2);
+		err = PTR_ERR(exp2);
+		/*
+		 * We normally allow NFS clients to continue
+		 * "underneath" a mountpoint that is not exported.
+		 * The exception is V4ROOT, where no traversal is ever
+		 * allowed without an explicit export of the new
+		 * directory.
+		 */
+		if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
+			err = 0;
 		path_put(&path);
 		goto out;
 	}