diff --git a/0001-launch-direct-Omit-locking-option-for-non-file-disks.patch b/0001-launch-direct-Omit-locking-option-for-non-file-disks.patch
new file mode 100644
index 0000000..47b7294
--- /dev/null
+++ b/0001-launch-direct-Omit-locking-option-for-non-file-disks.patch
@@ -0,0 +1,36 @@
+From 35320dd0edb94d09d231bcded57aa883a5e7c784 Mon Sep 17 00:00:00 2001
+From: Lars Seipel <ls@slrz.net>
+Date: Thu, 23 Nov 2017 06:15:28 +0100
+Subject: [PATCH] launch: direct: Omit locking option for non-file disks
+ (RHBZ#1516094)
+
+QEMU does not accept options unrecognized by the block driver
+in use. Disable locking only for read-only disks that are
+file-backed, as that's the only block driver it is supported
+with.
+
+Signed-off-by: Lars Seipel <ls@slrz.net>
+---
+ lib/launch-direct.c | 6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+diff --git a/lib/launch-direct.c b/lib/launch-direct.c
+index 87ac121c7..678c8c68d 100644
+--- a/lib/launch-direct.c
++++ b/lib/launch-direct.c
+@@ -260,7 +260,11 @@ add_drive_standard_params (guestfs_h *g, struct backend_direct_data *data,
+     append_list ("cache=unsafe");
+     if (drv->disk_label)
+       append_list_format ("serial=%s", drv->disk_label);
+-    if (data->qemu_mandatory_locking)
++
++    /* Add the file-specific locking option only for files, as qemu
++     * won't accept options unknown to the block driver in use.
++     */
++    if (data->qemu_mandatory_locking && drv->src.protocol == drive_protocol_file)
+       append_list ("file.backing.file.locking=off");
+   }
+ 
+-- 
+2.15.1
+
diff --git a/libguestfs.spec b/libguestfs.spec
index 96f5d9d..dc4c3f4 100644
--- a/libguestfs.spec
+++ b/libguestfs.spec
@@ -36,7 +36,7 @@ Summary:       Access and modify virtual machine disk images
 Name:          libguestfs
 Epoch:         1
 Version:       1.37.34
-Release:       1%{?dist}
+Release:       3%{?dist}
 License:       LGPLv2+
 
 # Source and patches.
@@ -60,6 +60,9 @@ Source6:       yum.conf.in
 Source7:       libguestfs.keyring
 %endif
 
+# Upstream patch to fix locking on NBD drives.
+Patch1:        0001-launch-direct-Omit-locking-option-for-non-file-disks.patch
+
 # Basic build requirements for the library and virt tools.
 BuildRequires: gcc
 BuildRequires: supermin-devel >= 5.1.18
@@ -1373,6 +1376,9 @@ install -m 0644 utils/boot-benchmark/boot-benchmark.1 $RPM_BUILD_ROOT%{_mandir}/
 
 
 %changelog
+* Sun Dec  3 2017 Richard W.M. Jones <rjones@redhat.com> - 1:1.37.34-3
+- Fix locking on NBD drives.
+
 * Fri Nov 17 2017 Richard W.M. Jones <rjones@redhat.com> - 1:1.37.34-1
 - New upstream version 1.37.34.