From 0b1e515d1c5dddf3c11eddbe6d53167d2fb6aaab Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zyan@redhat.com>
Date: Thu, 25 Jan 2018 12:08:47 +0800
Subject: [PATCH] osdc/ObjectCacher: don't merge TX buffer heads

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
---
 src/osdc/ObjectCacher.cc | 33 +++++++++++++++++----------------
 src/osdc/ObjectCacher.h  |  1 +
 2 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/src/osdc/ObjectCacher.cc b/src/osdc/ObjectCacher.cc
index 3f549f96631c8..e9040c9a0aa05 100644
--- a/src/osdc/ObjectCacher.cc
+++ b/src/osdc/ObjectCacher.cc
@@ -157,9 +157,6 @@ ObjectCacher::BufferHead *ObjectCacher::Object::split(BufferHead *left,
 void ObjectCacher::Object::merge_left(BufferHead *left, BufferHead *right)
 {
   assert(oc->lock.is_locked());
-  assert(left->end() == right->start());
-  assert(left->get_state() == right->get_state());
-  assert(left->can_merge_journal(right));
 
   ldout(oc->cct, 10) << "merge_left " << *left << " + " << *right << dendl;
   if (left->get_journal_tid() == 0) {
@@ -196,6 +193,17 @@ void ObjectCacher::Object::merge_left(BufferHead *left, BufferHead *right)
   ldout(oc->cct, 10) << "merge_left result " << *left << dendl;
 }
 
+bool ObjectCacher::Object::can_merge_bh(BufferHead *left, BufferHead *right)
+{
+  if (left->end() != right->start() ||
+      left->get_state() != right->get_state() ||
+      !left->can_merge_journal(right))
+    return false;
+  if (left->is_tx() && left->last_write_tid != right->last_write_tid)
+    return false;
+  return true;
+}
+
 void ObjectCacher::Object::try_merge_bh(BufferHead *bh)
 {
   assert(oc->lock.is_locked());
@@ -210,9 +218,7 @@ void ObjectCacher::Object::try_merge_bh(BufferHead *bh)
   assert(p->second == bh);
   if (p != data.begin()) {
     --p;
-    if (p->second->end() == bh->start() &&
-	p->second->get_state() == bh->get_state() &&
-	p->second->can_merge_journal(bh)) {
+    if (can_merge_bh(p->second, bh)) {
       merge_left(p->second, bh);
       bh = p->second;
     } else {
@@ -222,10 +228,7 @@ void ObjectCacher::Object::try_merge_bh(BufferHead *bh)
   // to the right?
   assert(p->second == bh);
   ++p;
-  if (p != data.end() &&
-      p->second->start() == bh->end() &&
-      p->second->get_state() == bh->get_state() &&
-      p->second->can_merge_journal(bh))
+  if (p != data.end() && can_merge_bh(bh, p->second))
     merge_left(bh, p->second);
 }
 
@@ -1152,12 +1155,6 @@ void ObjectCacher::bh_write_commit(int64_t poolid, sobject_t oid,
       if (bh->start() >= start+(loff_t)length)
 	break;
 
-      if (bh->start() < start &&
-	  bh->end() > start+(loff_t)length) {
-	ldout(cct, 20) << "bh_write_commit skipping " << *bh << dendl;
-	continue;
-      }
-
       // make sure bh is tx
       if (!bh->is_tx()) {
 	ldout(cct, 10) << "bh_write_commit skipping non-tx " << *bh << dendl;
@@ -1171,6 +1168,10 @@ void ObjectCacher::bh_write_commit(int64_t poolid, sobject_t oid,
 	continue;
       }
 
+      // we don't merge tx buffers. tx buffer should be within the range
+      assert(bh->start() >= start);
+      assert(bh->end() <= start+(loff_t)length);
+
       if (r >= 0) {
 	// ok!  mark bh clean and error-free
 	mark_clean(bh);
diff --git a/src/osdc/ObjectCacher.h b/src/osdc/ObjectCacher.h
index 58b3e7aafeea3..01ab8829b88ac 100644
--- a/src/osdc/ObjectCacher.h
+++ b/src/osdc/ObjectCacher.h
@@ -341,6 +341,7 @@ class ObjectCacher {
     // mid-level
     BufferHead *split(BufferHead *bh, loff_t off);
     void merge_left(BufferHead *left, BufferHead *right);
+    bool can_merge_bh(BufferHead *left, BufferHead *right);
     void try_merge_bh(BufferHead *bh);
 
     bool is_cached(loff_t off, loff_t len) const;
-- 
2.39.5