[Libguestfs] [PATCH] lib: direct: Disable qemu locking when opening drives readonly.

[Richard W.M. Jones]

Since qemu 2.10, qemu locks all drives even when they are opened
readonly.  This disables this locking in this safe case.

Incomplete fix for
https://bugzilla.redhat.com/show_bug.cgi?id=1417306
---
 lib/launch-direct.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/launch-direct.c b/lib/launch-direct.c
index 3b848165c..e5465539d 100644
--- a/lib/launch-direct.c
+++ b/lib/launch-direct.c
@@ -221,8 +221,11 @@ add_drive_standard_params (guestfs_h *g, struct backend_direct_data *data,
     file = guestfs_int_drive_source_qemu_param (g, &drv->src);
     append_list_format ("file=%s", file);
 
-    if (drv->readonly)
+    if (drv->readonly) {
       append_list ("snapshot=on");
+      if (guestfs_int_version_ge (&data->qemu_version, 2, 10, 0))
+        append_list ("locking=off");
+    }
     append_list_format ("cache=%s",
                         drv->cachemode ? drv->cachemode : "writeback");
     if (drv->src.format)
-- 
2.13.2