- if (qemu_supports (g, NULL) == -1)
- return -1;
-
- /* Only SCSI and virtio drivers support readonly mode.
- * This is only supported as a QEMU feature since 2010/01.
- */
- int supports_ro = 0;
- if ((STREQ (drive_if, "scsi") || STREQ (drive_if, "virtio")) &&
- qemu_supports (g, "readonly=on"))
- supports_ro = 1;
-
- size_t len = strlen (filename) + 100;
- char buf[len];
-
- snprintf (buf, len, "file=%s,snapshot=on,%sif=%s",
- filename,
- supports_ro ? "readonly=on," : "",
- drive_if);
+ snprintf (buf, len, "file=%s,snapshot=on,if=%s", filename, drive_if);