sheepdog: adopting protocol update for VDI locking

The update is required for supporting iSCSI multipath. It doesn't
affect behavior of QEMU driver but adding a new field to vdi request
struct is required.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Liu Yuan <namei.unix@gmail.com>
Cc: MORITA Kazutaka <morita.kazutaka@gmail.com>
Signed-off-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

block/sheepdog.c

@@ -103,6 +103,9 @@
 #define SD_INODE_SIZE (sizeof(SheepdogInode))
 #define CURRENT_VDI_ID 0
 
+#define LOCK_TYPE_NORMAL 0
+#define LOCK_TYPE_SHARED 1      /* for iSCSI multipath */
+
 typedef struct SheepdogReq {
     uint8_t proto_ver;
     uint8_t opcode;
@@ -166,7 +169,8 @@ typedef struct SheepdogVdiReq {
     uint8_t copy_policy;
     uint8_t reserved[2];
     uint32_t snapid;
-    uint32_t pad[3];
+    uint32_t type;
+    uint32_t pad[2];
 } SheepdogVdiReq;
 
 typedef struct SheepdogVdiRsp {
@@ -1090,6 +1094,7 @@ static int find_vdi_name(BDRVSheepdogState *s, const char *filename,
     memset(&hdr, 0, sizeof(hdr));
     if (lock) {
         hdr.opcode = SD_OP_LOCK_VDI;
+        hdr.type = LOCK_TYPE_NORMAL;
     } else {
         hdr.opcode = SD_OP_GET_VDI_INFO;
     }
@@ -1793,6 +1798,7 @@ static void sd_close(BlockDriverState *bs)
     memset(&hdr, 0, sizeof(hdr));
 
     hdr.opcode = SD_OP_RELEASE_VDI;
+    hdr.type = LOCK_TYPE_NORMAL;
     hdr.base_vdi_id = s->inode.vdi_id;
     wlen = strlen(s->name) + 1;
     hdr.data_length = wlen;