From 46c200a0f470f4acd9714c60e141f85334018d25 Mon Sep 17 00:00:00 2001
From: xinxin shu <xinxin.shu@intel.com>
Date: Tue, 27 Oct 2015 11:34:25 +0800
Subject: [PATCH] optimize clone write path if object-map is enabled

Fixes : #13500

Signed-off-by: xinxin shu <xinxin.shu@intel.com>
---
 src/librbd/AioRequest.cc | 41 ++++++++++++++++++++++++++++------------
 src/librbd/AioRequest.h  |  8 +++++---
 2 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/src/librbd/AioRequest.cc b/src/librbd/AioRequest.cc
index b6fc1f918a6a1f..8405b42dc405ab 100644
--- a/src/librbd/AioRequest.cc
+++ b/src/librbd/AioRequest.cc
@@ -395,6 +395,7 @@ namespace librbd {
   void AbstractWrite::send_pre() {
     assert(m_ictx->owner_lock.is_locked());
 
+    m_object_exist = m_ictx->object_map.object_may_exist(m_object_no);
     bool write = false;
     {
       RWLock::RLocker snap_lock(m_ictx->snap_lock);
@@ -464,19 +465,16 @@ namespace librbd {
 
   void AbstractWrite::send_write() {
     ldout(m_ictx->cct, 20) << "send_write " << this << " " << m_oid << " "
-			   << m_object_off << "~" << m_object_len << dendl;
-
-    m_state = LIBRBD_AIO_WRITE_FLAT;
-    guard_write();
-    add_write_ops(&m_write);
-    assert(m_write.size() != 0);
+			   << m_object_off << "~" << m_object_len 
+                           << " object exist " << m_object_exist << dendl;
 
-    librados::AioCompletion *rados_completion =
-      librados::Rados::aio_create_completion(this, NULL, rados_req_cb);
-    int r = m_ictx->data_ctx.aio_operate(m_oid, rados_completion, &m_write,
-					 m_snap_seq, m_snaps);
-    assert(r == 0);
-    rados_completion->release();
+    if (m_object_exist) {
+      m_state = LIBRBD_AIO_WRITE_FLAT;
+      send_write_op();
+    } else {
+      m_state = LIBRBD_AIO_WRITE_GUARD;
+      complete(-ENOENT);
+    }
   }
 
   void AbstractWrite::send_copyup()
@@ -504,6 +502,18 @@ namespace librbd {
       m_ictx->copyup_list_lock.Unlock();
     }
   }
+  void AbstractWrite::send_write_op()
+  {
+    add_write_ops(&m_write);
+    assert(m_write.size() != 0);
+
+    librados::AioCompletion *rados_completion =
+      librados::Rados::aio_create_completion(this, NULL, rados_req_cb);
+    int r = m_ictx->data_ctx.aio_operate(m_oid, rados_completion, &m_write,
+					 m_snap_seq, m_snaps);
+    assert(r == 0);
+    rados_completion->release();
+  }
 
   void AioWrite::add_write_ops(librados::ObjectWriteOperation *wr) {
     if (m_ictx->enable_alloc_hint && !m_ictx->object_map.object_may_exist(m_object_no))
@@ -523,4 +533,11 @@ namespace librbd {
       AbstractWrite::guard_write();
     }
   }
+  void AioRemove::send_write() {
+    ldout(m_ictx->cct, 20) << "send_write " << this << " " << m_oid << " "
+			   << m_object_off << "~" << m_object_len << dendl;
+    m_state = LIBRBD_AIO_WRITE_FLAT;
+    guard_write();
+    send_write_op();
+  }
 }
diff --git a/src/librbd/AioRequest.h b/src/librbd/AioRequest.h
index 885cbce887684a..9021f50ab6af25 100644
--- a/src/librbd/AioRequest.h
+++ b/src/librbd/AioRequest.h
@@ -128,7 +128,6 @@ namespace librbd {
     virtual bool should_complete(int r);
     virtual void send();
 
-  private:
     /**
      * Writes go through the following state machine to deal with
      * layering and the object map:
@@ -163,6 +162,7 @@ namespace librbd {
      * The write starts in _WRITE_GUARD or _FLAT depending on whether or not
      * there is a parent overlap.
      */
+  protected:
     enum write_state_d {
       LIBRBD_AIO_WRITE_GUARD,
       LIBRBD_AIO_WRITE_COPYUP,
@@ -172,11 +172,11 @@ namespace librbd {
       LIBRBD_AIO_WRITE_ERROR
     };
 
-  protected:
     write_state_d m_state;
     librados::ObjectWriteOperation m_write;
     uint64_t m_snap_seq;
     std::vector<librados::snap_t> m_snaps;
+    bool m_object_exist;
 
     virtual void add_write_ops(librados::ObjectWriteOperation *wr) = 0;
     virtual const char* get_write_type() const = 0;
@@ -185,11 +185,12 @@ namespace librbd {
     virtual bool post_object_map_update() {
       return false;
     }
+    virtual void send_write();
+    virtual void send_write_op();
 
   private:
     void send_pre();
     bool send_post();
-    void send_write();
     void send_copyup();
   };
 
@@ -264,6 +265,7 @@ namespace librbd {
     }
 
     virtual void guard_write();
+    virtual void send_write();
 
   private:
     uint8_t m_object_state;