diff --git a/[refs] b/[refs]
index 0667d438d426..c889dc1b8f3b 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 05ffe24f5290dc095f98fbaf84afe51ef404ccc5
+refs/heads/master: 55725513b5ef9d462aa3e18527658a0362aaae83
diff --git a/trunk/fs/nfs/nfs4proc.c b/trunk/fs/nfs/nfs4proc.c
index 3c787d02131b..ba837d977a1a 100644
--- a/trunk/fs/nfs/nfs4proc.c
+++ b/trunk/fs/nfs/nfs4proc.c
@@ -4726,6 +4726,20 @@ nfs4_proc_lock(struct file *filp, int cmd, struct file_lock *request)
 
 	if (state == NULL)
 		return -ENOLCK;
+	/*
+	 * Don't rely on the VFS having checked the file open mode,
+	 * since it won't do this for flock() locks.
+	 */
+	switch (request->fl_type & (F_RDLCK|F_WRLCK|F_UNLCK)) {
+	case F_RDLCK:
+		if (!(filp->f_mode & FMODE_READ))
+			return -EBADF;
+		break;
+	case F_WRLCK:
+		if (!(filp->f_mode & FMODE_WRITE))
+			return -EBADF;
+	}
+
 	do {
 		status = nfs4_proc_setlk(state, cmd, request);
 		if ((status != -EAGAIN) || IS_SETLK(cmd))