From 26151ec62f5b675ba799bcfce0027705a940b742 Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zheng.z.yan@intel.com>
Date: Tue, 13 May 2014 13:50:47 +0800
Subject: [PATCH] mds: lower IO priority of storing backtrace

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
---
 src/mds/CInode.cc  | 7 ++++++-
 src/mds/CInode.h   | 2 +-
 src/mds/journal.cc | 2 +-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/mds/CInode.cc b/src/mds/CInode.cc
index 94705de26f67e..a3d6d5eea5a7f 100644
--- a/src/mds/CInode.cc
+++ b/src/mds/CInode.cc
@@ -1026,11 +1026,14 @@ struct C_Inode_StoredBacktrace : public Context {
   }
 };
 
-void CInode::store_backtrace(Context *fin)
+void CInode::store_backtrace(Context *fin, int op_prio)
 {
   dout(10) << "store_backtrace on " << *this << dendl;
   assert(is_dirty_parent());
 
+  if (op_prio < 0)
+    op_prio = CEPH_MSG_PRIO_DEFAULT;
+
   auth_pin(this);
 
   int64_t pool;
@@ -1045,6 +1048,7 @@ void CInode::store_backtrace(Context *fin)
   ::encode(bt, bl);
 
   ObjectOperation op;
+  op.priority = op_prio;
   op.create(false);
   op.setxattr("parent", bl);
 
@@ -1071,6 +1075,7 @@ void CInode::store_backtrace(Context *fin)
       continue;
 
     ObjectOperation op;
+    op.priority = op_prio;
     op.create(false);
     op.setxattr("parent", bl);
 
diff --git a/src/mds/CInode.h b/src/mds/CInode.h
index 727d43ea7c41e..adc0bf7d364a3 100644
--- a/src/mds/CInode.h
+++ b/src/mds/CInode.h
@@ -527,7 +527,7 @@ public:
   void _fetched(bufferlist& bl, bufferlist& bl2, Context *fin);  
 
   void build_backtrace(int64_t pool, inode_backtrace_t& bt);
-  void store_backtrace(Context *fin);
+  void store_backtrace(Context *fin, int op_prio=-1);
   void _stored_backtrace(version_t v, Context *fin);
   void _mark_dirty_parent(LogSegment *ls, bool dirty_pool=false);
   void clear_dirty_parent();
diff --git a/src/mds/journal.cc b/src/mds/journal.cc
index 44e51840c1e7a..53bcc6906e69b 100644
--- a/src/mds/journal.cc
+++ b/src/mds/journal.cc
@@ -199,7 +199,7 @@ void LogSegment::try_to_expire(MDS *mds, C_GatherBuilder &gather_bld, int op_pri
     assert(in->is_auth());
     if (in->can_auth_pin()) {
       dout(15) << "try_to_expire waiting for storing backtrace on " << *in << dendl;
-      in->store_backtrace(gather_bld.new_sub());
+      in->store_backtrace(gather_bld.new_sub(), op_prio);
     } else {
       dout(15) << "try_to_expire waiting for unfreeze on " << *in << dendl;
       in->add_waiter(CInode::WAIT_UNFREEZE, gather_bld.new_sub());
-- 
2.39.5