cls_rbd: add async version of object_map_load

Most librbd object map interactions are moving to async state machines.
The sync version must remain until the librbd image refresh operation
is converted to a state machine due to the sheer volume of locks held
blocking the AIO thread.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>

diff --git a/src/cls/rbd/cls_rbd_client.cc b/src/cls/rbd/cls_rbd_client.cc
index e4a7500aa6ad06d03536065d56ea54fc55a1d3bb..31a31a445b1372d42a6e6a19b84f647ee07e69f1 100644 (file)
--- a/src/cls/rbd/cls_rbd_client.cc
+++ b/src/cls/rbd/cls_rbd_client.cc
@@ -17,6 +17,11 @@ namespace librbd {
 
 namespace {
 
+void rados_callback(rados_completion_t c, void *arg) {
+  Context *ctx = reinterpret_cast<Context *>(arg);
+  ctx->complete(rados_aio_get_return_value(c));
+}
+
 struct C_GetChildren : public Context {
   librados::IoCtx *ioctx;
   std::string oid;
@@ -59,13 +64,46 @@ struct C_GetChildren : public Context {
     }
     on_finish->complete(r);
   }
+};
+
+struct C_ObjectMapLoad : public Context {
+  librados::IoCtx *ioctx;
+  std::string oid;
+  ceph::BitVector<2> *object_map;
+  Context *on_finish;
+  bufferlist out_bl;
+
+  C_ObjectMapLoad(librados::IoCtx *_ioctx, const std::string &_oid,
+                  ceph::BitVector<2> *_object_map, Context *_on_finish)
+    : ioctx(_ioctx), oid(_oid), object_map(_object_map), on_finish(_on_finish) {
+  }
+
+  void send() {
+    bufferlist in_bl;
+    librados::ObjectReadOperation op;
+    op.exec("rbd", "object_map_load", in_bl);
+
+    librados::AioCompletion *rados_completion =
+       librados::Rados::aio_create_completion(this, rados_callback, NULL);
+    int r = ioctx->aio_operate(oid, rados_completion, &op, &out_bl);
+    assert(r == 0);
+    rados_completion->release();
+  }
 
-  static void rados_callback(rados_completion_t c, void *arg) {
-    Context *ctx = reinterpret_cast<Context *>(arg);
-    ctx->complete(rados_aio_get_return_value(c));
+  virtual void finish(int r) {
+    if (r == 0) {
+      try {
+        bufferlist::iterator it = out_bl.begin();
+        ::decode(*object_map, it);
+      } catch (const buffer::error &err) {
+        r = -EBADMSG;
+      }
+    }
+    on_finish->complete(r);
   }
 };
 
+
 } // anonymous namespace
 
     int get_immutable_metadata(librados::IoCtx *ioctx, const std::string &oid,
@@ -783,6 +821,7 @@ struct C_GetChildren : public Context {
     int object_map_load(librados::IoCtx *ioctx, const std::string &oid,
                        ceph::BitVector<2> *object_map)
     {
+      // TODO eliminate sync version
       bufferlist in;
       bufferlist out;
       int r = ioctx->exec(oid, "rbd", "object_map_load", in, out);
@@ -799,6 +838,14 @@ struct C_GetChildren : public Context {
       return 0;
     }
 
+    void object_map_load(librados::IoCtx *ioctx, const std::string &oid,
+                         ceph::BitVector<2> *object_map, Context *on_finish)
+    {
+      C_ObjectMapLoad *req = new C_ObjectMapLoad(ioctx, oid, object_map,
+                                                 on_finish);
+      req->send();
+    }
+
     void object_map_save(librados::ObjectWriteOperation *rados_op,
                          const ceph::BitVector<2> &object_map)
     {

diff --git a/src/cls/rbd/cls_rbd_client.h b/src/cls/rbd/cls_rbd_client.h
index 660875c08d87e3ae27539a5375740778eac11e27..98bd1cfcb1f41a520fc239cf35fe82de72b667c9 100644 (file)
--- a/src/cls/rbd/cls_rbd_client.h
+++ b/src/cls/rbd/cls_rbd_client.h
@@ -129,6 +129,8 @@ namespace librbd {
     // operations on the rbd_object_map.$image_id object
     int object_map_load(librados::IoCtx *ioctx, const std::string &oid,
                        ceph::BitVector<2> *object_map);
+    void object_map_load(librados::IoCtx *ioctx, const std::string &oid,
+                         ceph::BitVector<2> *object_map, Context *on_finish);
     void object_map_save(librados::ObjectWriteOperation *rados_op,
                          const ceph::BitVector<2> &object_map);
     void object_map_resize(librados::ObjectWriteOperation *rados_op,