nfsd4: nfsv4 clients should cross mountpoints

Allow NFS v4 clients to seamlessly cross mount point without
have to set either the 'crossmnt' or the 'nohide' export
options.
Signed-Off-By: Steve Dickson <steved@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

fs/nfsd/vfs.c

@@ -89,6 +89,12 @@ struct raparm_hbucket {
 #define RAPARM_HASH_MASK	(RAPARM_HASH_SIZE-1)
 static struct raparm_hbucket	raparm_hash[RAPARM_HASH_SIZE];
 
+static inline int
+nfsd_v4client(struct svc_rqst *rq)
+{
+    return rq->rq_prog == NFS_PROGRAM && rq->rq_vers == 4;
+}
+
 /* 
  * Called from nfsd_lookup and encode_dirent. Check if we have crossed 
  * a mount point.
@@ -115,7 +121,8 @@ nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
 		path_put(&path);
 		goto out;
 	}
-	if ((exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
+	if (nfsd_v4client(rqstp) ||
+		(exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
 		/* successfully crossed mount point */
 		/*
 		 * This is subtle: path.dentry is *not* on path.mnt