From: Jason Dillaman <dillaman@redhat.com>
Date: Tue, 7 May 2019 16:49:02 +0000 (-0400)
Subject: librbd: helper method to generate data object OIDs on-demand
X-Git-Tag: v15.1.0~2664^2~3
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=10bebfcac0af4c770c7e08206e63b5e37073b0c0;p=ceph.git

librbd: helper method to generate data object OIDs on-demand

The new generator avoids multiple string length and copy operations
that are currently required in the Striper.

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

diff --git a/src/librbd/ImageCtx.cc b/src/librbd/ImageCtx.cc
index a20069c6e163..5a8bf337745a 100644
--- a/src/librbd/ImageCtx.cc
+++ b/src/librbd/ImageCtx.cc
@@ -409,9 +409,7 @@ public:
   }
 
   string ImageCtx::get_object_name(uint64_t num) const {
-    char buf[object_prefix.length() + 32];
-    snprintf(buf, sizeof(buf), format_string, num);
-    return string(buf);
+    return util::data_object_name(this, num);
   }
 
   uint64_t ImageCtx::get_stripe_unit() const
diff --git a/src/librbd/Utils.h b/src/librbd/Utils.h
index c0b68b9f873a..0f9ebe3a82db 100644
--- a/src/librbd/Utils.h
+++ b/src/librbd/Utils.h
@@ -6,11 +6,13 @@
 
 #include "include/rados/librados.hpp"
 #include "include/rbd_types.h"
+#include "include/ceph_assert.h"
 #include "include/Context.h"
 #include "common/zipkin_trace.h"
 
 #include <atomic>
 #include <type_traits>
+#include <stdio.h>
 
 namespace librbd {
 
@@ -107,6 +109,19 @@ const std::string header_name(const std::string &image_id);
 const std::string old_header_name(const std::string &image_name);
 std::string unique_lock_name(const std::string &name, void *address);
 
+template <typename I>
+std::string data_object_name(I* image_ctx, uint64_t object_no) {
+  char buf[RBD_MAX_OBJ_NAME_SIZE];
+  size_t length = snprintf(buf, RBD_MAX_OBJ_NAME_SIZE,
+                           image_ctx->format_string, object_no);
+  ceph_assert(length < RBD_MAX_OBJ_NAME_SIZE);
+
+  std::string oid;
+  oid.reserve(RBD_MAX_OBJ_NAME_SIZE);
+  oid.append(buf, length);
+  return oid;
+}
+
 librados::AioCompletion *create_rados_callback(Context *on_finish);
 
 template <typename T>