1 files changed, 3 insertions, 3 deletions
diff --git a/src/guestfs.c b/src/guestfs.c
index d6c8d603..764f7298 100644
--- a/src/guestfs.c
+++ b/src/guestfs.c
@@ -836,9 +836,6 @@ int
 guestfs__add_drive_ro_with_if (guestfs_h *g, const char *filename,
                                const char *drive_if)
 {
-  size_t len = strlen (filename) + 64;
-  char buf[len];
-
   if (strchr (filename, ',') != NULL) {
     error (g, _("filename cannot contain ',' (comma) character"));
     return -1;
@@ -849,6 +846,9 @@ guestfs__add_drive_ro_with_if (guestfs_h *g, const char *filename,
     return -1;
   }
 
+  size_t len = strlen (filename) + 64;
+  char buf[len];
+
   snprintf (buf, len, "file=%s,snapshot=on,if=%s", filename, drive_if);
 
   return guestfs__config (g, "-drive", buf);