rbdtool: init rbd block id, later will be used for rename

1 files changed, 45 insertions, 0 deletions

diff --git a/src/cls_rbd.cc b/src/cls_rbd.cc
index d4cae65d2e6..a216097e3f3 100644
--- a/src/cls_rbd.cc
+++ b/src/cls_rbd.cc
@@ -18,6 +18,7 @@ cls_handle_t h_class;
 cls_method_handle_t h_snapshots_list;
 cls_method_handle_t h_snapshot_add;
 cls_method_handle_t h_snapshot_revert;
+cls_method_handle_t h_assign_bid;
 
 static int snap_read_header(cls_method_context_t hctx, bufferlist& bl)
 {
@@ -236,6 +237,47 @@ int snapshot_revert(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
   return out->length();
 }
 
+/* assign block id. This method should be called on the rbd_info object */
+int rbd_assign_bid(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  struct rbd_info info;
+  int rc;
+  bufferlist bl;
+
+  rc = cls_cxx_read(hctx, 0, sizeof(info), &bl);
+  if (rc < 0 && rc != -EEXIST)
+    return rc;
+
+  if (rc && rc < (int)sizeof(info)) {
+    CLS_LOG("bad rbd_info object, read %d bytes, expected %d", rc, sizeof(info));
+    return -EIO;
+  }
+
+  uint64_t max_id;
+  if (rc) {
+    memcpy(&info, bl.c_str(), sizeof(info));
+    max_id = info.max_id + 1;
+    info.max_id = max_id;
+  } else {
+    memset(&info, 0, sizeof(info));
+    max_id = 0;
+  }
+
+  bufferlist newbl;
+  bufferptr bp(sizeof(info));
+  memcpy(bp.c_str(), &info, sizeof(info));
+  newbl.push_back(bp);
+  rc = cls_cxx_write_full(hctx, &newbl);
+  if (rc < 0) {
+    CLS_LOG("error writing rbd_info, got rc=%d", rc);
+    return rc;
+  }
+
+  ::encode(max_id, *out);
+
+  return out->length();
+}
+
 void __cls_init()
 {
   CLS_LOG("Loaded rbd class!");
@@ -245,6 +287,9 @@ void __cls_init()
   cls_register_cxx_method(h_class, "snap_add", CLS_METHOD_RD | CLS_METHOD_WR, snapshot_add, &h_snapshot_add);
   cls_register_cxx_method(h_class, "snap_revert", CLS_METHOD_RD | CLS_METHOD_WR, snapshot_revert, &h_snapshot_revert);
 
+  /* assign a unique block id for rbd blocks */
+  cls_register_cxx_method(h_class, "assign_bid", CLS_METHOD_RD | CLS_METHOD_WR, rbd_assign_bid, &h_assign_bid);
+
   return;
 }