[virtio-9p] This patch implements TLERROR/RLERROR on the qemu 9P server.

Signed-off-by: NArun R Bharadwaj <arun@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

hw/virtio-9p.c

@@ -844,17 +844,24 @@ static void complete_pdu(V9fsState *s, V9fsPDU *pdu, ssize_t len)
     int8_t id = pdu->id + 1; /* Response */
 
     if (len < 0) {
-        V9fsString str;
         int err = -len;
+        len = 7;
 
-        str.data = strerror(err);
-        str.size = strlen(str.data);
+        if (s->proto_version != V9FS_PROTO_2000L) {
+            V9fsString str;
+
+            str.data = strerror(err);
+            str.size = strlen(str.data);
+
+            len += pdu_marshal(pdu, len, "s", &str);
+            id = P9_RERROR;
+        }
 
-        len = 7;
-        len += pdu_marshal(pdu, len, "s", &str);
         len += pdu_marshal(pdu, len, "d", err);
 
-        id = P9_RERROR;
+        if (s->proto_version == V9FS_PROTO_2000L) {
+            id = P9_RLERROR;
+        }
     }
 
     /* fill out the header */

hw/virtio-9p.h

@@ -13,6 +13,8 @@
 #define VIRTIO_9P_MOUNT_TAG 0
 
 enum {
+    P9_TLERROR = 6,
+    P9_RLERROR,
     P9_TSTATFS = 8,
     P9_RSTATFS,
     P9_TLOPEN = 12,